WO2023124812A1 - Projection device - Google Patents

Abstract

A projection device (100), comprising a light source (10), an optical engine (20), and a lens (30). The optical engine (20) comprises a light valve. The light valve is located on the light emitting side of the light source (10). The light valve is configured to modulate an illumination beam incident to the light valve into a projection beam and then reflect the projection beam. The lens (30) is located on a reflection light path of the light valve, and the lens (30) is configured to image the projection beam. The lens (30) comprises a first lens group (31) and a second lens group (32). The first lens group (31) comprises at least one sub-lens group. The at least one sub-lens group comprises at least two lenses, and the at least two lenses are cemented to each other. The second lens group (32) is located on the light emitting side of the first lens group (31).

Description

projection equipment

This application claims priority to Chinese patent application number 202111667597.1 filed on December 31, 2021; priority to Chinese patent application number 202111662486.1 filed on December 31, 2021; December 2021 The priority of the Chinese patent application with application number 202111681922.X filed on the 31st, the entire content of which is incorporated in this application by reference.

technical field

The present disclosure relates to the technical field of projection display, and in particular, to a projection device.

Background technique

With the continuous development of projection display technology, projection display products are becoming more and more popular among consumers as a substitute for TV. Projection display technology refers to a technology that controls the light source by plane image information, and uses the optical system and projection space to enlarge the image and display it on the projection screen.

Contents of the invention

A projection device is provided, and the projection device includes a light source, an optical machine and a lens. The light source is configured to emit an illumination beam. The optical machine is configured to modulate the illumination beam emitted by the light source to obtain a projection beam. The light machine includes a light valve. The light valve is located on the light exit side of the light source. The light valve is configured to modulate an illumination beam incident on the light valve into a projection beam and then reflect it. The lens is located on the reflected light path of the light valve. The lens is configured to image the projection beam. The lens includes a first lens group and a second lens group. The first lens group is located on the light exit side of the light machine. The first lens group is configured to image the projected light beam incident to the first lens group. The first lens group includes at least one sub-lens group. The at least one sub-lens group includes at least two lenses, and the at least two lenses are glued to each other. The second lens group is located on the light emitting side of the first lens group. The second lens group is configured to re-image the projection beam imaged by the first lens group and reflect it to a preset position.

Description of drawings

In order to illustrate the technical solutions in the present disclosure more clearly, the following will briefly introduce the accompanying drawings required in some embodiments of the present disclosure, however, the accompanying drawings in the following description are only drawings of some embodiments of the present disclosure , for those skilled in the art, other drawings can also be obtained according to these drawings. In addition, the drawings in the following description can be regarded as schematic diagrams, and are not limitations on the actual size of the product involved in the embodiments of the present disclosure, the actual process of the method, the actual timing of signals, and the like.

FIG. 1 is a structural diagram of a projection device according to some embodiments;

Fig. 2 is a partial structural diagram of a projection device according to some embodiments;

3 is an optical path diagram of a light source, an optical machine, and a lens in a projection device according to some embodiments;

FIG. 4 is an arrangement diagram of tiny mirrors in a digital micromirror device according to some embodiments;

FIG. 5 is a structural diagram of another projection device according to some embodiments;

FIG. 6 is a structural diagram of a lens according to some embodiments;

Fig. 7 is a schematic diagram of TV distortion of a projected picture projected by a lens according to some embodiments;

8A is a ray fan diagram of an imaging plane at a projection screen according to some embodiments;

Figure 8B is another ray fan diagram of the imaging plane at the projection screen according to some embodiments;

8C is yet another ray fan diagram of the imaging plane at the projection screen according to some embodiments;

Fig. 9 is a structural diagram of another lens according to some embodiments;

10A is a ray fan diagram of an imaging surface at a digital micromirror device according to some embodiments;

FIG. 10B is another ray fan diagram of the imaging surface at the digital micromirror device according to some embodiments;

Fig. 10C is another ray fan diagram of the imaging surface at the digital micromirror device according to some embodiments;

Fig. 11 is a structural diagram of another lens according to some embodiments;

Fig. 12A is another ray fan diagram of the imaging surface at the digital micromirror device according to some embodiments;

Fig. 12B is another ray fan diagram of the imaging surface at the digital micromirror device according to some embodiments;

Fig. 12C is yet another ray fan diagram of the imaging plane at the digital micromirror device according to some embodiments.

Detailed ways

The technical solutions in some embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are only some of the embodiments of the present disclosure, not all of them. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments provided in the present disclosure belong to the protection scope of the present disclosure.

Throughout the specification and claims, unless the context requires otherwise, the term "comprise" and other forms such as the third person singular "comprises" and the present participle "comprising" are used Interpreted as the meaning of openness and inclusion, that is, "including, but not limited to". In the description of the specification, the terms "one embodiment", "some embodiments", "exemplary embodiments", "example", "specific examples" example)" or "some examples (some examples)" etc. are intended to indicate that specific features, structures, materials or characteristics related to the embodiment or examples are included in at least one embodiment or example of the present disclosure. Schematic representations of the above terms are not necessarily referring to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be included in any suitable manner in any one or more embodiments or examples.

Hereinafter, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of indicated technical features. Thus, a feature defined as "first" and "second" may explicitly or implicitly include one or more of these features. In the description of the embodiments of the present disclosure, unless otherwise specified, "plurality" means two or more.

In describing some embodiments, the expressions and "connected" and its derivatives may be used. The term "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral body; it can be a direct connection or an indirect connection through an intermediary. The embodiments disclosed herein are not necessarily limited by the context herein.

"A and/or B" includes the following three combinations: A only, B only, and a combination of A and B.

The use of "suitable for" or "configured to" herein means open and inclusive language that does not exclude devices that are suitable for or configured to perform additional tasks or steps.

As used herein, "about", "approximately" or "approximately" includes the stated value as well as the average within the acceptable deviation range of the specified value, wherein the acceptable deviation range is as determined by one of ordinary skill in the art. Determined taking into account the measurement in question and the errors associated with the measurement of a particular quantity (ie, limitations of the measurement system).

As used herein, "parallel", "perpendicular", and "equal" include the stated situation and the situation similar to the stated situation, the range of the similar situation is within the acceptable deviation range, wherein the The stated range of acceptable deviation is as determined by one of ordinary skill in the art taking into account the measurement in question and errors associated with measurement of the particular quantity (ie, limitations of the measurement system).

Usually, the projection light beam emitted from the lens of the projection device will be projected onto a screen or a wall, and reflected into human eyes through the screen or wall, so as to realize the display of the projected picture. At present, there needs to be a certain distance between the lens of the projection device (such as a projector) and the projection screen, so that the projection picture is clear. However, if there is an object between the projection screen and the lens, the object will block the projection light beam emitted by the lens, so that the projection picture on the projection screen will be missing and the display effect will be affected. Therefore, projection equipment usually adopts an ultra-short-focus lens. However, due to the short projection distance of the ultra-short-focus lens, the requirement for a large field of view and high imaging requirements, and the cost and miniaturization of projection equipment must also be considered, making the design of the lens more difficult.

In addition, the lens in the projection device usually adopts a telecentric optical path structure, so that the lens has better imaging quality. However, in the telecentric optical path structure, the optical path of the projected light beam modulated by the light valve needs to be incident into the lens in a direction parallel to the optical axis of the lens. Therefore, the design of the lens is complicated, and the volume of the rear end of the optical system is relatively large. Large, resulting in an increase in lens size. In addition, a larger rear working distance is required between the light valve and the lens to install a beam splitting prism to split and divert the illumination beam provided by the light source. In this way, the volume of the projection device is further increased, and the space occupied by the projection device is larger. Moreover, the cost of the dichroic prism is relatively high, which is not conducive to reducing the cost of the projection device.

In order to solve the above problems, some embodiments of the present disclosure provide a projection device 100 .

Fig. 1 is a structural diagram of a projection device according to some embodiments. As shown in FIG. 1 , the projection device 100 includes a complete machine housing 40 (only part of the complete machine housing 40 is shown in FIG. 1 ), a light source 10 assembled in the complete machine housing 40 , an optical engine 20 and a lens 30 . The light source 10 is configured to provide an illumination beam. The optical machine 20 is configured to use an image signal to modulate the illumination beam provided by the light source 10 to obtain a projection beam. The lens 30 is configured to project the projection light beam on a screen or a wall to form an image.

The light source 10, the light engine 20 and the lens 30 are sequentially connected along the light beam propagation direction, and each is wrapped by a corresponding housing. The housings of the light source 10 , the light engine 20 and the lens 30 support the corresponding optical components and make the optical components meet certain sealing or airtight requirements.

Fig. 2 is a partial structural diagram of a projection device according to some embodiments.

As shown in FIG. 2 , one end of the optical machine 20 is connected to the light source 10 , and the light source 10 and the optical machine 20 are arranged along the outgoing direction of the illumination beam of the projection device 100 (refer to the M direction in FIG. 2 ). The other end of the optical machine 20 is connected to the lens 30 , and the optical machine 20 and the lens 30 are arranged along the outgoing direction of the projection light beam of the projection device 100 (refer to the N direction in FIG. 2 ). The outgoing direction M of the illuminating light beam is approximately perpendicular to the outgoing direction N of the projection light beam. On the one hand, this connection structure can adapt to the characteristics of the optical path of the reflective light valve in the optical machine 20. On the other hand, it is also beneficial to shorten the length of the optical path in one dimension. The length is beneficial to the structural arrangement of the whole machine. For example, when the light source 10, the light engine 20 and the lens 30 are arranged in one dimension direction (such as the M direction), the length of the optical path in this dimension direction will be very long, which is not conducive to the structural arrangement of the whole machine. The reflective light valve will be described later. It should be noted that, when the projection device 100 adopts a non-telecentric structure, the angle between the emission direction M of the illumination light beam and the emission direction N of the projection light beam can also be other angles.

In some embodiments, the light source 10 can sequentially provide the three primary colors of light (other colors can also be added on the basis of the three primary colors of light). white light formed. Alternatively, the light source 10 can also output the three primary colors of light at the same time, continuously emitting white light. The light source 10 may include a laser that emits a laser beam of at least one color, such as a red laser beam, a blue laser beam or a green laser beam.

In some embodiments, the laser may comprise a monochromatic laser. That is, the laser emits a laser beam of one color. In this case, the light source 10 further includes a fluorescent wheel configured to convert the color of the laser beam under the irradiation of the laser beam emitted by the laser to obtain light of other colors. In this way, the monochromatic laser can cooperate with the fluorescent wheel to emit light of different colors in time sequence. Of course, the laser can also be a multicolor laser. That is, the laser emits laser beams of various colors. Alternatively, the light source 10 includes a plurality of lasers emitting laser beams of different colors.

Fig. 3 is an optical path diagram of a light source, an optical engine and a lens in a projection device according to some embodiments.

The illumination beam emitted by the light source 10 enters the light machine 20 . As shown in FIG. 3 , the optical machine 20 includes a lens assembly 230 and a digital micromirror device (Digital Micromirror Device, DMD) 250. The lens assembly 230 can converge the illumination beam provided by the light source 10 to the digital micromirror device 250 , and the digital micromirror device 250 modulates the illumination beam to obtain a projection beam, and reflects the projection beam to the lens 30 .

In the optical machine 20, the digital micromirror device 250 uses the image signal to modulate the illumination beam provided by the light source 10, that is, to control the projection beam to display different brightness and gray scale for different pixels of the image to be displayed, so as to finally form an optical image, Therefore, the digital micromirror device 250 is also called a light modulation device or a light valve. According to whether the light modulation device (or light valve) transmits or reflects the illumination light beam, the light modulation device can be classified into a transmissive light modulation device or a reflective light modulation device. For example, the digital micromirror device 250 shown in FIG. 3 reflects the illumination light beam, that is, it is a reflective light modulation device. The liquid crystal light valve transmits the illumination beam, so it is a transmissive light modulation device. In addition, according to the number of light modulation devices used in the optical machine 20, the optical machine 20 can be divided into a single-chip system, a two-chip system or a three-chip system.

The digital micromirror device 250 is applied in a DLP (Digital Light Processing, digital light processing) projection architecture, and the optical machine 20 shown in FIG. 3 uses a DLP projection architecture. The light modulation device in some embodiments of the present disclosure is a digital micromirror device 250 .

FIG. 4 is an arrangement diagram of tiny mirrors in a digital micromirror device according to some embodiments.

As shown in Figure 4, the digital micromirror device 250 comprises thousands of tiny mirror mirrors 2501 that can be individually driven to rotate. The lens 2501) corresponds to a pixel in the projected image to be displayed. The image signal can be converted into digital codes such as 0 and 1 after being processed, and the tiny mirror 2501 can swing in response to these digital codes. Controlling the duration of each tiny reflective mirror 2501 in the on state and the off state respectively, to realize the gray scale of each pixel in a frame of image. In this way, the digital micromirror device 250 can modulate the illuminating light beam, and then realize the display of the projected picture. The open state of the tiny reflective mirror 2501 is the state where the tiny reflective mirror 2501 is and can be maintained when the illumination light beam emitted by the light source 10 is reflected by the tiny reflective mirror 2501 and can enter the lens 30 . The off state of the tiny reflective mirror 2501 is the state that the tiny reflective mirror 2501 is in and can be maintained when the illuminating light beam sent by the light source 10 does not enter the lens 30 after being reflected by the tiny reflective mirror 2501.

In some embodiments, the digital micromirror device 250 includes a 0.47-inch or 0.66-inch 4K high-resolution digital micromirror device, so as to realize large-scale high-resolution projection display.

In some embodiments of the present disclosure, as shown in FIG. 3 , the projection device 100 adopts a non-telecentric architecture. In the non-telecentric architecture, the optical path of the projection beam modulated by the digital micromirror device 250 does not need to enter the lens 30 along a direction parallel to the optical axis of the lens 30 . In this way, there is no need to install a dichroic prism in the optical machine 20 , which simplifies the structure of the projection device 100 , reduces the volume of the projection device 100 , and reduces the design and manufacturing difficulty and cost of the projection device 100 . It should be noted that the dichroic prism can change the propagation direction of the illumination beam from the light source 10, so that the illumination beam enters the light valve. Described dichroic prism can be total internal reflection (Total Internal Reflection, TIR) prism or refraction total internal reflection (Refraction Total Internal Reflection, RTIR) prism, or also can be other types of prisms,

Fig. 5 is a structural diagram of another projection device according to some embodiments.

In some embodiments. As shown in FIG. 5 , the projection device 100 further includes a projection screen 60 . The projection screen 60 is disposed on the light emitting path of the lens 30 and is configured to receive the projection light beam emitted by the lens 30 for image display. For example, the projection screen 60 may be a curtain or a wall, which is not limited in the present disclosure.

The lens 30 in some embodiments of the present disclosure is described in detail below.

FIG. 6 is a block diagram of a lens according to some embodiments.

In some embodiments, as shown in FIG. 6 , the lens 30 includes a first lens group 31 and a second lens group 32 . The first lens group 31 is located on the light emitting side of the digital micromirror device 250 , and the first lens group 31 is configured to form an image of the projected light beam incident on the first lens group 31 . The second lens group 32 is positioned at the side of the first lens group 31 away from the digital micromirror device 250 (i.e. the light exit side of the first lens group 31), and the second lens group 32 is configured to form an image through the first lens group 31 The projected light beam is imaged again, and the re-imaged projected light beam is reflected to a preset position. It should be noted that the preset position may refer to the position where the projection screen 60 is located.

In some embodiments of the present disclosure, by adopting the lens 30 of the secondary imaging structure, the projected light beam emitted by the light valve (such as DMD 250) can pass through the first lens group 31 after passing through the first lens group 31 and the second lens group 32 for the first imaging, and after being reflected by the second lens group 32, the second imaging is performed on the projection screen 60 at the preset position. The projection screen 60 may be disposed on a side of the first lens group 31 away from the second lens group 32 . In this way, the distance between the lens 30 and the projection screen 60 is small, and the probability of objects appearing between the lens 30 and the projection screen 60 is small, thereby reducing the situation that the screen is blocked, saving space, and facilitating the projection device 100. miniaturization.

In some embodiments, as shown in FIG. 6 , the first lens group 31 includes a rear group lens group 3011 , a middle group lens group 3012 and a front group lens group 3013 . The rear group mirror group 3011 , the middle group mirror group 3012 and the front group mirror group 3013 are sequentially arranged along a direction away from the digital micromirror device 250 . The front group lens group 3013 is close to the second lens group 32, the middle group lens group 3012 is located on the side of the front group lens group 3013 away from the second lens group 32, and the rear group lens group 3011 is located at the side of the middle group lens group 3012 away from the front group lens One side of the group 3013, and close to the digital micromirror device 250. Moreover, the optical axes of the second lens group 32 , the rear group lens group 3011 , the middle group lens group 3012 and the front group lens group 3013 are collinear with each other.

In some embodiments, as shown in FIG. 6 , the rear group lens group 3011 includes a first lens 101 , a second lens 102 , a third lens 103 , a fourth lens 104 , a fifth lens 105 and a sixth lens 106 . The first lens 101 , the second lens 102 , the third lens 103 , the fourth lens 104 , the fifth lens 105 and the sixth lens 106 are arranged in sequence along a direction close to the second lens group 32 .

The first lens 101 is an aspheric lens. The second lens 102 , the third lens 103 , the fourth lens 104 , the fifth lens 105 and the sixth lens 106 are spherical lenses respectively. The spherical aberration and astigmatism of the lens 30 can be reduced and the resolution of the lens 30 can be improved by setting the lens (such as the first lens 101 ) close to the light incident side of the lens 30 as an aspherical lens.

The diopters of the first lens 101 , the third lens 103 , and the fifth lens 105 are respectively positive numbers, and the diopters of the second lens 102 , the fourth lens 104 , and the sixth lens 106 are respectively negative numbers. It should be noted that when light is incident from one object to another medium with a different optical density than the object, the propagation direction of the light will be deflected. This phenomenon is called refraction, and the diopter is Refers to the unit of refractive power of the medium in the refractive phenomenon.

In some embodiments, the first lens 101 includes a glass aspheric lens. Since the first lens 101 is located at the light incident side of the lens 30 and is close to the light source 10 , the temperature of the first lens 101 is relatively high during the working process of the projection device 100 . Because the glass aspheric lens has a low thermal expansion coefficient, the temperature coefficient of the refractive index of the glass aspheric lens is small, the refractive index is not easy to change with temperature, and the optical performance of the glass aspheric lens is stable. Therefore, the projection device 100 can have good imaging quality by using a glass aspherical lens.

In some embodiments, the first lens 101 is an axisymmetric aspheric lens. For example, the first lens 101 is a convex-concave aspheric lens.

In some embodiments, as shown in FIG. 6 , the third lens 103 and the fourth lens 104 are glued together to form the first sub-lens group X1 . The first sub-lens group X1 is configured to reduce the spherical aberration of different spectra in the lens 30 and correct the astigmatism and field curvature of the lens 30 . The Abbe number of the fourth lens 104 is smaller than the Abbe number of the third lens 103 , and the refractive index of the fourth lens 104 is greater than that of the third lens 103 . For example, the Abbe number VD1 of the third lens 103 is any value in the range of 50-70 (50<VD1<70), and the refractive index ND1 of the third lens 103 is greater than 1.6 (ND1>1.6). For example, the Abbe number VD1 of the third lens 103 is 50, 55, 60, 65 or 70 and so on.

It should be noted that the Abbe number is also called "dispersion coefficient", and the Abbe number is an index used to represent the dispersion ability of a transparent medium. Generally speaking, the larger the refractive index of the medium, the more serious the dispersion of light passing through the medium, and the smaller the Abbe number of the medium; the smaller the refractive index of the medium, the lighter the dispersion of light passing through the medium, and the smaller the Abbe number of the medium. The larger the Abbe number. The dispersion refers to a phenomenon in which polychromatic light is decomposed into monochromatic light to form a spectrum. For example, since different colors of light correspond to different refractive indices when propagating in the medium, the different colors of light have different propagation paths when propagating in the medium, resulting in dispersion phenomenon.

In some embodiments, as shown in FIG. 6 , the middle group lens group 3012 includes the seventh lens 107 and the eighth lens 108 . The seventh lens 107 and the eighth lens 108 are arranged in sequence along a direction close to the second lens group 32 .

The seventh lens 107 is a spherical lens, and the eighth lens 108 is an aspheric lens. The diopter of the seventh lens 107 is a positive number, and the diopter of the eighth lens 108 may be a negative number. Astigmatism and coma aberration of the lens 30 can be improved by disposing an aspheric lens (such as the eighth lens 108 ) in the middle group lens group 3012 .

In some embodiments, the eighth lens 108 is an axisymmetric aspheric lens (eg, concave-convex aspheric lens), and is made of glass material.

In some embodiments, the middle group lens group 3012 is movable. For example, the middle group lens group 3012 moves along the direction of the optical axis of the middle group lens group 3012 . Of course, since the optical axes of the second lens group 32, the rear group lens group 3011, the middle group lens group 3012, and the front group lens group 3013 are collinear with each other, the middle group lens group 3012 can also be aligned along the front group lens group 3012 or the rear lens group. The direction of the optical axis of the group lens group 3011 or the second lens group 32 moves. By adjusting the relative positions of the middle group mirror group 3012, the front group mirror group 3013 and the rear group mirror group 3011, it is possible to focus and image projection images of different sizes.

In some embodiments, as shown in FIG. 6 , the front group lens group 3013 includes a ninth lens 109 , a tenth lens 110 , an eleventh lens 111 , a twelfth lens 112 and a thirteenth lens 113 . The ninth lens 109 , the tenth lens 110 , the eleventh lens 111 , the twelfth lens 112 and the thirteenth lens 113 are arranged in sequence along a direction close to the second lens group 32 .

The ninth lens 109 , the tenth lens 110 , the eleventh lens 111 and the twelfth lens 112 are respectively spherical lenses, and the thirteenth lens 113 is an aspheric lens. Astigmatism and distortion of the lens 30 can be reduced by disposing an aspheric lens (such as the thirteenth lens 113 ) in the front group lens group 3013 near the second lens group 32 .

The diopters of the ninth lens 109 , the eleventh lens 111 , and the thirteenth lens 113 are positive numbers, and the diopters of the tenth lens 110 and the twelfth lens 112 are negative numbers.

In some embodiments, the thirteenth lens 113 is an axisymmetric aspheric lens (eg, concave-convex aspheric lens).

In some embodiments, the thirteenth lens 113 includes a plastic aspherical lens. Since the aperture of the aspheric lens (the thirteenth lens 113) close to the second lens group 32 needs to be relatively large, if the thirteenth lens 113 adopts a glass aspheric lens, then the design and processing of the thirteenth lens 113 are more difficult. . In addition, because the distance between the thirteenth lens 113 and the light source 10 is relatively long, the thirteenth lens 113 is less affected by temperature. Therefore, the thirteenth lens 113 can adopt an easy-to-form plastic aspheric lens to reduce cost and manufacturing difficulty.

In some embodiments, as shown in FIG. 6 , the eleventh lens 111 and the twelfth lens 112 are cemented together to form the second sub-lens group X2. The second sub-lens group X2 is configured to correct residual lateral chromatic aberration of the lens 30 . The Abbe number of the eleventh lens 111 is smaller than the Abbe number of the twelfth lens 112 , and the refractive index of the eleventh lens 111 is greater than that of the twelfth lens 112 . For example, the Abbe number VD2 of the eleventh lens 111 is any value in the range of 15-300 (15<VD2<300). For example, the Abbe number VD2 of the eleventh lens 111 is 15, 50, 100, 150, 200, 250 or 300. And the refractive index ND2 of the eleventh lens 111 is greater than 1.85 (ND2>1.85).

In some embodiments, the front group lens group 3013 is movable. By adjusting the relative positions of the front group lens group 3013 and the second lens group 32 , the distortion of the lens 30 under projection images of different sizes can be corrected. The distortion refers to the aberration caused by the lens having different magnifications to different parts of the object when an object is imaged by the lens.

In some embodiments of the present disclosure, by arranging two doublet lens groups (such as the first sub-lens group X1 and the second sub-lens group X2) in the lens 30, chromatic aberration can be effectively corrected to solve the problems of red, green and blue light. To solve the problem of large deviation, improving the quality of the projected image can also reduce the processing accuracy requirements of the lens 30 , which facilitates the design and manufacture of the lens 30 .

It should be noted that, in the phenomenon of dispersion, light rays of different colors have different propagation paths when propagating in the medium, so there are differences between the optical paths of light rays of different colors, and the aberration caused by this difference is called chromatic aberration (referred to as chromatic aberration). The vertical chromatic aberration refers to the difference caused by different heights on the image plane after light beams of different wavelengths in the off-axis field of view pass through the lens. The spherical aberration refers to the aberration caused by the misalignment of the corresponding image points on the optical axis due to the different projection angles of the object points of the optical axis on the lens. The conical light beam emitted by the off-axis object point cannot converge into a clear point at the ideal image plane after being imaged by the optical system, but a comet-shaped spot. The imaging error of this optical system is called coma. The field curvature means that after the light beam passes through the optical system, the intersection point of the light beam does not coincide with the ideal image point. Although a clear image point can be obtained at each specific point, the entire image plane is a curved surface. This phenomenon is called the so-called Describe the field song.

In some embodiments, as shown in FIG. 6 , the second lens group 32 includes a reflector 3021 configured to reflect the projected light beam emitted by the first lens group 31 for imaging, and to reflect the re-imaged projected light beam Reflect to the preset position. By setting the reflector 3021, the optical path of the lens 30 can be folded, the length of the lens 30 can be reduced, and thus the size of the lens 30 can be reduced.

In some embodiments, the mirror 3021 may be a concave mirror. The concave reflector can reduce the divergence angle of light to realize the display of large-scale projected images. For example, the mirror 3021 is an aspheric mirror or a free-form mirror. When the second lens group 32 compresses the projected light beam in a large proportion, the lens 30 is prone to distortion, and the use of an aspheric reflector or a free-form reflector can effectively correct the astigmatism and distortion of the lens 30 and improve the display of the projected picture Effect.

In some embodiments, the total diopter between the first lens group 31 and the second lens group 32 in the lens 30 is a positive number to converge light.

In the lens 30 shown in FIG. 6, the equivalent focal length F of the lens 30, the equivalent focal length FB of the rear group lens group 3011, the equivalent focal length FM of the middle group lens group 3012, and the equivalent focal length FF of the front group lens group 3013 and the equivalent focal length FC of the second lens group 32 satisfy the following relationship:

1<|FB/F|<12;

40<|FM/F|<600;

320<|FF/F|<360;

5<|FC/F|<10.

The equivalent focal length refers to: converting the imaging angle of view on photosensitive elements of different sizes into the lens focal length corresponding to the same imaging angle of view on the 135 model camera, the converted focal length is the equivalent focal length. A 135 camera is a camera that uses 135 film. 135 film is a roll-shaped photosensitive film with a height of 35mm perforated on both sides, also known as 35mm film, or Leica (Leica) film.

In some embodiments, the throw ratio of the lens 30 adopting the non-telecentric architecture shown in FIG. 6 may be any value within the range of 0.20-0.25. For example, the throw ratio of the lens 30 is 0.20, 0.21, 0.22, 0.23, 0.24 or 0.25. The lens 30 can meet the requirement of using an ultra-short-focus projection lens, shorten the distance between the lens 30 and the projection screen 60, and can realize the display of large-scale projection images.

In some embodiments, as shown in FIG. 6 , the length L1 of the first lens group 31 and the distance L2 between the first lens group 31 and the second lens group 32 satisfy the following relationship:

1.5<L1/L2<2.

The distance L2 between the first lens group 31 and the second lens group 32, and the back working distance BFL of the lens 30 satisfy the following relationship:

0.2<BFL/L2<0.4.

The back working distance BFL of the lens 30 refers to the distance between the light valve (such as the DMD 250) and the last face in the lens 30 on which the projection beam is incident.

After performing optical simulation on the lens 30 in Fig. 6, the F number of the lens 30 is 2.35, the effective focal length (Effective Focal Length, FFL) of the lens 30 is 3.206mm, and the offset (the center of the projected light beam emitted by the light valve and the optical axis The distance between them, the ratio of the half-height of the projection light beam emitted by the light valve) is any value in the range of 140% to 150%, the resolution of the lens 30 can reach 93lp/mm, and the size of the projection screen of the projection device 100 It can be any value within the range of 90 inches to 120 inches, and the throw ratio of the lens 30 (that is, the ratio of the projection distance to the length of the projection screen) is any value within the range of 0.23 to 0.25. The projection distance refers to the shortest distance between the lens 30 and the projection screen.

Fig. 7 is a schematic diagram of TV distortion of a projected image projected by a lens according to some embodiments. TV distortion refers to the comparative relationship between the maximum value and the minimum value of the actual image height, which can reflect the degree of distortion of the projected image of the lens 30 . As shown in FIG. 7 , the intersection points of the grid represent ideal pixel positions of the projected picture, and each independent cross point represents the pixel position of the actual projected picture. When the size of the projected image is 100 inches (2214×1245mm ² ), after passing through the lens 30 provided by some embodiments of the present disclosure, the maximum TV distortion of the projected image is -0.4125%, and the display quality of the projected image is relatively high.

Figure 8A is a ray fan diagram of an imaging plane at a projection screen according to some embodiments. Figure 8B is another ray fan diagram of an imaging plane at a projection screen according to some embodiments. 8C is yet another ray fan diagram of an imaging plane at a projection screen according to some embodiments. Fig. 8A, Fig. 8B and Fig. 8C respectively show that the wavelength is 450nm, 525nm, 620nm under the conditions of normalized minimum field of view, center field of view and maximum field of view, and the dominant wavelength light on the horizontal axis and vertical axis respectively The aberration value between .

As shown in FIGS. 8A to 8C , the two graphs in each field of view are the light fan graphs of the lens 30 in the meridional direction and the sagittal direction respectively, and the light fan graphs are centered on the optical axis. The horizontal axes P _X , P _Y in each graph represent the pupil height under the condition of the field of view, and the vertical axes _EX , E _Y represent the X component and Y component of the lateral aberration between the light of each wavelength and the chief ray. The optical fan diagrams in FIGS. 8A to 8C have a maximum scale of ±1000 μm.

As shown in FIG. 8A , FIG. 8B and FIG. 8C , the coincidence degree of the curves of different wavelengths in each field of view is high, and the maximum value of the vertical axis is also small. Therefore, the lens 30 of some embodiments of the present disclosure can effectively improve the color shift and improve the display effect of the projected picture.

In some embodiments of the present disclosure, the aberration of a large field of view is corrected by setting an aspheric lens, an aspheric mirror or a free-form mirror, thereby improving the resolution of the lens, thereby realizing the display of high-resolution projected images. Moreover, by setting the surface type (such as spherical surface and aspherical surface) and diopter of each optical lens, and controlling the number of optical lenses, the miniaturization of the projection device 100 can be realized, and the projection device 100 can perform full-color laser projection display. By arranging two doublet lens groups and three aspherical lenses, the complexity and volume of the lens 30 structure can be reduced, and the cost and processing difficulty can be reduced. Moreover, through two doublet lens groups, the problem of large chromatic aberration deviation of monochromatic lenses can be solved.

In the foregoing, the lens 30 includes two doublet lens groups (for example, the first sub-lens group X1 and the second sub-lens group X2), and the rear group lens group 3011 and the front group lens group 3013 respectively include a doublet lens group as an example Be explained. Of course, the present disclosure is not limited thereto, and in some embodiments, the rear group lens group 3011 may include two doublet lens groups.

Fig. 9 is a structural diagram of another lens according to some embodiments.

In some embodiments, as shown in FIG. 9, the rear group lens group 3011 includes a third sub-lens group X3 and a fourth sub-lens group X4, and the third sub-lens group X3 and the fourth sub-lens group X4 are doublet lenses respectively. Group. The third sub-lens group X3 is configured to improve spherical aberration of different spectra in the lens 30 , and to correct axial chromatic aberration and vertical chromatic aberration of the lens 30 . The fourth sub-lens group X4 is configured to correct residual spherical aberration and astigmatism of the lens 30 .

For example, as shown in FIG. 9, the rear group lens group 3011 includes a first lens 201, a second lens 202, a third lens 203, a fourth lens 204, a fifth lens 205, a sixth lens 206, a seventh lens 207, a Eight lenses 208 , ninth lenses 209 and tenth lenses 210 . The first lens 201, the second lens 202, the third lens 203, the fourth lens 204, the fifth lens 205, the sixth lens 206, the seventh lens 207, the eighth lens 208, the ninth lens 209 and the tenth lens 210 along the The directions close to the second lens group 32 are arranged in sequence.

The first lens 201 is an aspherical lens. The second lens 202 , the third lens 203 , the fourth lens 204 , the fifth lens 205 , the sixth lens 206 , the seventh lens 207 , the eighth lens 208 , the ninth lens 209 and the tenth lens 210 are spherical lenses. When the first lens 201 is an aspheric lens, the function is the same as that when the first lens 101 is an aspheric lens, and will not be repeated here.

The diopters of the first lens 201, the fourth lens 204, the fifth lens 205, the sixth lens 206, the eighth lens 208 and the tenth lens 210 are positive numbers, and the second lens 202, the third lens 203, the seventh lens 207 and The diopter of the ninth lens 209 is a negative number.

In some embodiments, the first lens 201 includes a glass aspheric lens. The function of the glass aspheric lens has been described above and will not be repeated here.

In some embodiments, the first lens 201 is an axisymmetric aspheric lens. For example, the first lens 201 is a biconvex aspherical lens.

The third lens 203 and the fourth lens 204 are cemented together to form the third sub-lens group X3. The Abbe number of the fourth lens 204 is greater than the Abbe number of the third lens 203 , and the refractive index of the fourth lens 204 is smaller than that of the third lens 203 . For example, the Abbe number VD3 of the third lens 203 is any value in the range of 20-40 (20<VD3<40), and the refractive index ND3 of the third lens 203 is greater than 1.8 (ND3>1.8). For example, the Abbe number VD3 of the third lens 203 is 20, 25, 30, 35 or 40 and so on.

The eighth lens 208 and the ninth lens 209 are glued together to form the fourth sub-lens group X4. The Abbe number VD4 of the eighth lens 208 and the Abbe number VD5 of the ninth lens 209 are any value in the range of 20-40 (20<VD4(VD5)<40). For example, the Abbe number VD4 of the eighth lens 208 and the Abbe number VD5 of the ninth lens 209 are 20, 25, 30, 35, or 40, respectively. The refractive index ND4 of the eighth lens 208 and the refractive index ND5 of the ninth lens 209 are respectively greater than 1.7 (Nd4(ND5)>1.7). The refractive index ND4 of the eighth lens 208 is smaller than the refractive index ND5 of the ninth lens 209 , and the Abbe number VD4 of the eighth lens 208 is smaller than the Abbe number VD5 of the ninth lens 209 .

In this case, as shown in FIG. 9 , the middle group lens group 3012 includes the eleventh lens 211 and the twelfth lens 212 . The eleventh lens 211 and the twelfth lens 212 are arranged in sequence along a direction close to the second lens group 32 . The eleventh lens 211 and the twelfth lens 212 are spherical lenses respectively. The diopter of the eleventh lens 211 is a positive number, and the diopter of the twelfth lens 212 is a negative number.

Moreover, as shown in FIG. 9 , the front group lens group 3013 includes a thirteenth lens 213 and a fourteenth lens 214 . The thirteenth lens 213 and the fourteenth lens 214 are arranged in sequence along a direction close to the second lens group 32 . The thirteenth lens 213 and the fourteenth lens 214 are aspherical lenses respectively, and the diopters of the thirteenth lens 213 and the fourteenth lens 214 are negative numbers respectively. Astigmatism and distortion of the lens 30 can be reduced by disposing aspheric lenses (such as the thirteenth lens 213 and the fourteenth lens 214 ) in the front group lens group 3013 near the second lens group 32 .

In some embodiments, the thirteenth lens 213 and the fourteenth lens 214 are respectively axisymmetric aspheric lenses, for example, the thirteenth lens 213 and the fourteenth lens 214 are respectively biconcave aspheric lenses.

In some embodiments, the thirteenth lens 213 and the fourteenth lens 214 respectively include plastic aspheric lenses. Since the apertures of the aspheric lenses (the thirteenth lens 213 and the fourteenth lens 214) close to the second lens group 32 need to be larger, if the thirteenth lens 213 and the fourteenth lens 214 adopt glass aspheric lenses, Therefore, the design and processing of the thirteenth lens 213 and the fourteenth lens 214 are more difficult. Since the distance between the thirteenth lens 213 and the fourteenth lens 214 is far from the light source 10 , the thirteenth lens 213 and the fourteenth lens 214 are less affected by temperature. Therefore, the thirteenth lens 213 and the fourteenth lens 214 can use plastic aspheric lenses that are easy to form, so as to reduce cost and manufacturing difficulty.

In the lens 30 shown in FIG. 9, the equivalent focal length F of the lens 30, the equivalent focal length FB of the rear group lens group 3011, the equivalent focal length FM of the middle group lens group 3012, and the equivalent focal length FF of the front group lens group 3013 and the equivalent focal length FC of the second lens group 32 satisfy the following relationship:

1<|FB/F|<15;

110<|FM/F|<130;

5<|FF/F|<20;

5<|FC/F|<15.

In some embodiments, the throw ratio of the lens 30 adopting the non-telecentric architecture shown in FIG. 9 can be any value within the range of 0.20-0.30. For example, the throw ratio of the lens 30 is 0.20, 0.22, 0.24, 0.26, 0.28 or 0.30. The lens 30 can meet the requirement of using an ultra-short-focus projection lens, shorten the distance between the lens 30 and the projection screen 60 , and can realize the display of a large-sized projected image.

In some embodiments, as shown in FIG. 9 , the length L1 of the first lens group 301 and the distance L2 between the first lens group 31 and the second lens group 32 satisfy the following relationship:

1.0<L1/L2<1.4.

The distance L2 between the first lens group 31 and the second lens group 32, and the back working distance BFL of the lens 30 satisfy the following relationship:

0.15<BFL/L2<0.35.

After performing optical simulation on the lens 30 in Fig. 9, the F-number of the lens 30 is 2.25, the effective focal length of the lens 30 is 3.06mm, the offset is 140%-150%, and the resolution of the lens 30 can reach 93 lp/mm. The size of the projection screen of the projection device 100 is any value within the range of 90 inches to 120 inches, and the throw ratio of the lens 30 is any value within the range of 0.23 to 0.25.

Moreover, when the size of the projected image is 100 inches, after passing through the lens 30 in FIG. 9 , the maximum value of the TV distortion of the projected image is -0.2395%, and the display quality of the projected image is relatively high.

Fig. 10A is a ray fan diagram of an imaging surface at a digital micromirror device according to some embodiments, Fig. 10B is another ray fan diagram of an imaging surface at a digital micromirror device according to some embodiments, and Fig. 10C is a ray fan diagram according to some embodiments Yet another ray fan diagram of the imaging plane at the digital micromirror device of the embodiment. Fig. 10A, Fig. 10B and Fig. 10C respectively show that the wavelength is 450nm, 525nm, 620nm under the conditions of normalized minimum field of view, central field of view and maximum field of view, and the main wavelength light is respectively on the horizontal axis and the vertical axis The aberration value between . The fan diagrams in FIGS. 10A to 10C have a maximum scale of ±10 μm.

As shown in Fig. 10A to Fig. 10C, the coincidence degree of the curves of different wavelengths in each field of view is relatively high, and the maximum value of the vertical axis is also small. Therefore, the use of the lens 30 in Fig. 9 can effectively improve the color shift and improve the projection The display effect of the screen.

In the lens 30 shown in FIG. 9 , by setting the surface type (such as spherical surface and aspherical surface) and diopter of each optical lens, and controlling the number of optical lenses, it is possible to achieve full color while realizing the miniaturization of the projection device 100. Laser projection display. By arranging two doublet lens groups and three aspherical lenses, the complexity and volume of the lens 30 structure can be reduced, and the cost and processing difficulty can be reduced. Moreover, through two doublet lens groups, the problem of large chromatic aberration deviation of monochromatic lenses can be solved.

In the foregoing, the rear group lens group 3011 of the lens 30 includes two doublet lens groups (eg, the third sub-lens group X3 and the fourth sub-lens group X4 ) as an example for illustration. Of course, the present disclosure is not limited thereto. In some embodiments, the lens 30 may also include a triplet lens group.

Fig. 11 is a structural diagram of another lens according to some embodiments.

In some embodiments, as shown in FIG. 11 , the rear group lens group 3011 includes a fifth sub-lens group X5, and the fifth sub-lens group X5 is a triplet lens group. The fifth sub-lens group X5 is configured to improve spherical aberration of different spectra in the lens 30 and correct coma and astigmatism of the lens 30 .

For example, as shown in Figure 11, the rear group lens group 3011 includes a first lens 301, a second lens 302, a third lens 303, a fourth lens 304, a fifth lens 305, a sixth lens 306, a seventh lens 307 and a Eight lenses 308 . The first lens 301, the second lens 302, the third lens 303, the fourth lens 304, the fifth lens 305, the sixth lens 306, the seventh lens 307 and the eighth lens 308 are arranged in sequence along the direction close to the second lens group 32 .

The first lens 301 is an aspheric lens. The second lens 302 , the third lens 303 , the fourth lens 304 , the fifth lens 305 , the sixth lens 306 , the seventh lens 307 and the eighth lens 308 are spherical lenses respectively.

The diopters of the first lens 301 , the third lens 303 , the fifth lens 305 and the eighth lens 308 are positive numbers, and the diopters of the second lens 302 , the fourth lens 304 , the sixth lens 306 and the seventh lens 307 are negative numbers.

The structure and function of the first lens 301 in FIG. 11 are similar to the structure and function of the first lens 201 in FIG. 9 above, and will not be repeated here.

The second lens 302 , the third lens 303 and the fourth lens 304 are cemented together to form a fifth sub-lens group X5 (triple cemented lens group). The refractive index of the third lens 303 is smaller than that of the second lens 302 and the fourth lens 304 . The Abbe number of the third lens 303 is greater than the Abbe numbers of the second lens 302 and the fourth lens 304. For example, the Abbe number VD6 of the third lens 303 is any value in the range of 50-70 (50<VD6<70), and the refractive index ND6 of the third lens 303 is greater than 1.5 (ND6>1.5). For example, the Abbe number VD6 of the third lens 303 is 50, 55, 60, 65 or 70.

In this case, as shown in FIG. 11 , the middle group lens group 3012 includes the ninth lens 309 . The ninth lens 309 is a spherical lens, and the diopter of the ninth lens 309 is a positive number.

Moreover, as shown in FIG. 11 , the front group lens group 3013 includes a tenth lens 310 , an eleventh lens 311 , a twelfth lens 312 and a thirteenth lens 313 . The tenth lens 310 , the eleventh lens 311 , the twelfth lens 312 and the thirteenth lens 313 are arranged in sequence along a direction close to the second lens group 32 . The tenth lens 310 and the eleventh lens 311 are respectively spherical lenses, and the twelfth lens 312 and the thirteenth lens 313 are respectively aspherical lenses. The diopter of the tenth lens 310 is a positive number, and the diopter of the eleventh lens 311 , the twelfth lens 312 and the thirteenth lens 313 are negative. Astigmatism and distortion of the lens 30 can be reduced by disposing aspheric lenses (such as the twelfth lens 312 and the thirteenth lens 313 ) in the front group lens group 3013 near the second lens group 32 .

In some embodiments, the twelfth lens 312 and the thirteenth lens 313 are respectively axisymmetric aspheric lenses, for example, the twelfth lens 312 and the thirteenth lens 313 are biconcave aspheric lenses respectively.

In some embodiments, the twelfth lens 312 and the thirteenth lens 313 respectively include plastic aspheric lenses, so as to reduce cost and manufacturing difficulty.

In the lens 30 shown in FIG. 11 , the equivalent focal length F of the lens 30, the equivalent focal length FB of the rear group lens group 3011, the equivalent focal length FM of the middle group lens group 3012, and the equivalent focal length FF of the front group lens group 3013 and the equivalent focal length FC of the second lens group 32 satisfy the following relationship:

1<|FB/F|<15;

10<|FM/F|<25;

10<|FF/F|<25;

5<|FC/F|<15.

In some embodiments, the throw ratio of the lens 30 adopting the non-telecentric architecture shown in FIG. 11 can be any value within the range of 0.20-0.30. For example, the throw ratio of the lens 30 is 0.20, 0.23, 0.25, 0.26, 0.28 or 0.30. The lens 30 can meet the requirement of using an ultra-short-focus projection lens, shorten the distance between the lens 30 and the projection screen 60 , and can realize the display of a large-sized projected image.

In some embodiments, as shown in FIG. 11 , the length L1 of the first lens group 301 and the distance L2 between the first lens group 31 and the second lens group 32 satisfy the following relationship:

1.0<L1/L2<1.3.

The distance L2 between the first lens group 31 and the second lens group 32, and the back working distance BFL of the lens 30 satisfy the following relationship:

0.1<BFL/L2<0.3.

After performing optical simulation on the lens 30 in Fig. 11, the F-number of the lens 30 is 2.25, the effective focal length of the lens 30 is 2.726mm, the offset is 140%-150%, and the resolution of the lens 30 can reach 93 lp/mm. The size of the projection screen of the projection device 100 is any value within the range of 90 inches to 120 inches, and the throw ratio of the lens 30 is any value within the range of 0.23 to 0.25.

Moreover, when the size of the projected image is 100 inches, after passing through the lens 30 in FIG. 11 , the maximum value of the TV distortion of the projected image is -0.2064%, and the display quality of the projected image is relatively high.

Fig. 12A is a ray fan diagram of an imaging surface at a digital micromirror device according to some embodiments, Fig. 12B is a ray fan diagram of an imaging surface at a digital micromirror device according to some embodiments, and Fig. 12C is a ray fan diagram according to some embodiments Ray fan diagram of the imaging plane at the digital micromirror device. Fig. 12A, Fig. 12B and Fig. 12C respectively show that the wavelength is 450nm, 525nm, 620nm under the conditions of normalized minimum field of view, central field of view and maximum field of view, and the main wavelength light is respectively on the horizontal axis and the vertical axis The aberration value between the . The fan diagrams in FIGS. 12A to 12C use a maximum scale of ±10 μm.

As shown in Fig. 12A to Fig. 12C, the coincidence degree of the curves of different wavelengths in each field of view is relatively high, and the maximum value of the vertical axis is also small. Therefore, the use of the lens 30 in Fig. 11 can effectively improve the color shift and improve the projection The display effect of the screen.

In the lens 30 shown in FIG. 11 , by setting the surface type (such as spherical surface and aspherical surface) and diopter of each optical lens, and controlling the number of optical lenses, it is possible to achieve full color while realizing the miniaturization of the projection device 100. Laser projection display. By setting a triplet lens group and three aspheric lenses, the complexity and volume of the lens 30 structure can be reduced, and the cost and processing difficulty can be reduced. Moreover, through two doublet lens groups, the problem of large chromatic aberration deviation of monochromatic lenses can be solved. Moreover, the lens 30 only includes a cemented lens group, which can effectively shorten the length of the lens 30 .

It should be noted that, during optical design, materials can be selected according to the Abbe number or the range of the refractive index of each lens for processing.

Those skilled in the art will understand that the disclosed scope of the present invention is not limited to the specific embodiments described above, and some elements of the embodiments can be modified and replaced without departing from the spirit of the application. The scope of the application is limited by the appended claims.

Claims (20)

A projection device comprising: a light source configured to emit an illumination beam; An optical machine, the optical machine is configured to modulate the illumination beam emitted by the light source to obtain a projection beam, and the optical machine includes: a light valve located on the light output side of the light source, the light valve configured to modulate the illumination beam incident on the light valve into a projected beam and then reflect; and A lens, located on the reflection light path of the light valve, the lens is configured to image the projected light beam, and the lens includes: The first lens group is located on the light exit side of the optical machine, the first lens group is configured to image the projection beam incident to the first lens group, and the first lens group includes: at least one sub-lens group comprising at least two lenses cemented to each other; and The second lens group is located on the light emitting side of the first lens group, and the second lens group is configured to re-image the projected light beam imaged by the first lens group and reflect it to a preset position. The projection device according to claim 1, wherein the first lens group comprises: The front group lens group includes a first sub-lens group, the first sub-lens group is a doublet lens group, and the first sub-lens group is configured to reduce the spherical aberration of different spectra in the lens, and correct all Astigmatism and curvature of field of the above lens; middle lens group; and The rear group lens group includes a second sub-lens group, the second sub-lens group is a doublet lens group, and the second sub-lens group is configured to correct the residual lateral chromatic aberration of the lens, and the rear group lens group, the middle group lens group and the front group lens group are sequentially arranged along the direction away from the optical machine. The projection device according to claim 2, wherein the rear group lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, the first lens, the The second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are sequentially arranged along a direction close to the second lens group; wherein The diopters of the first lens, the third lens, and the fifth lens are positive numbers, and the diopters of the second lens, the fourth lens, and the sixth lens are negative numbers; The third lens and the fourth lens are cemented together to form the second sub-lens group, the refractive index of the fourth lens is greater than that of the third lens, and the Abbe of the fourth lens is number is less than the Abbe number of the third lens; The first lens is an aspheric lens, and the second lens, the third lens, the fourth lens, the fifth lens and the sixth lens are spherical lenses respectively. The projection device according to claim 2, wherein the middle group lens group comprises: The seventh lens is a spherical lens; and The eighth lens is an aspheric lens, the seventh lens and the eighth lens are sequentially arranged along the direction close to the second lens group, the diopter of the seventh lens is a positive number, and the eighth lens diopters are negative. The projection device according to claim 2, wherein the front group lens group comprises a ninth lens, a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens, the ninth lens, the The tenth lens, the eleventh lens, the twelfth lens, and the thirteenth lens are sequentially arranged along a direction close to the second lens group; wherein, The diopter of the ninth lens, the eleventh lens, and the thirteenth lens is positive, and the diopter of the tenth lens and the twelve lens is negative; The eleventh lens and the twelfth lens are cemented together to form the first sub-lens group, and the refractive index of the twelfth lens is smaller than that of the eleventh lens; The Abbe number of the second lens is greater than the Abbe number of the eleventh lens; The ninth lens, the tenth lens, the eleventh lens and the twelfth lens are respectively spherical lenses, and the thirteenth lens is an aspherical lens. The projection device according to any one of claims 2 to 5, wherein the equivalent focal length of the lens, the equivalent focal length of the rear group lens group, the equivalent focal length of the middle group lens group, the The equivalent focal length of the front group lens group and the equivalent focal length of the second lens group satisfy the following relationship: 1<|FB/F|<12; 40<|FM/F|<600; 320<|FF/F|<360; 5<|FC/F|<10; Wherein, F represents the equivalent focal length of the lens, FB represents the equivalent focal length of the rear group lens group, FM represents the equivalent focal length of the middle group lens group, and FF represents the equivalent focal length of the front group lens group , FC represents the equivalent focal length of the second lens group. Projection apparatus according to any one of claims 2 to 6, wherein, The throw ratio of the lens is any value in the range of 0.2 to 0.25; The first lens group and the second lens group satisfy the following relationship: 1.5<L1/L2<2; The rear working distance of the lens satisfies the following relationship: 0.2<BFL/L2<0.4; Wherein, L1 represents the total length of the first lens group, L2 represents the distance between the first lens group and the second lens group, and BFL represents the back working distance of the lens. The projection device according to claim 1, wherein the first lens group comprises: Front group mirror group; middle lens group; and The rear group lens group, the rear group lens group, the middle group lens group and the front group lens group are sequentially arranged along the direction away from the optical machine, and the rear group lens group includes a third sub-lens group and a fourth sub-lens group, the third sub-lens group and the fourth sub-lens group are two doublet lens groups respectively, and the third sub-lens group is configured to improve spherical lenses of different spectra in the lens aberration, and to correct the axial chromatic aberration and the vertical axis chromatic aberration of the lens, the fourth sub-lens group is configured to correct the residual spherical aberration and astigmatism of the lens. The projection device according to claim 8, wherein the rear group lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens , the ninth lens and the tenth lens, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens , the eighth lens, the ninth lens, and the tenth lens are sequentially arranged along a direction close to the second lens group; wherein The diopters of the first lens, the fourth lens, the fifth lens, the sixth lens, the eighth lens and the tenth lens are positive numbers, and the second lens, the first lens The diopters of the three lenses, the seventh lens and the ninth lens are negative numbers; The third lens and the fourth lens are cemented together to form the third sub-lens group, the refractive index of the fourth lens is smaller than that of the third lens, and the Abbe number of the fourth lens is greater than the Abbe number of the third lens; The eighth lens and the ninth lens are cemented together to form the fourth sub-lens group, the refractive index of the eighth lens is smaller than that of the ninth lens, and the Abbe number of the eighth lens is less than the Abbe number of said ninth lens; The first lens is an aspherical lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens The lens, the ninth lens and the tenth lens are respectively spherical lenses. The projection device according to claim 8, wherein the middle group mirror group comprises: The eleventh lens is a spherical lens; and The twelfth lens is a spherical lens, and the eleventh lens and the twelfth lens are sequentially arranged along a direction close to the second lens group; wherein The diopter of the eleventh lens is a positive number, and the diopter of the twelfth lens is a negative number. The projection device according to claim 8, wherein the front group lens group comprises: The thirteenth lens is an aspherical lens; and The fourteenth lens is an aspheric lens, and the thirteenth lens and the fourteenth lens are sequentially arranged along a direction close to the second lens group; wherein The diopters of the thirteenth lens and the fourteenth lens are negative numbers. The projection device according to any one of claims 8 to 11, wherein the equivalent focal length of the lens, the equivalent focal length of the rear group lens group, the equivalent focal length of the middle group lens group, the The equivalent focal length of the front group lens group and the equivalent focal length of the second lens group satisfy the following relationship: 1<|FB/F|<15; 110<|FM/F|<130; 5<|FF/F|<20; 5<|FC/F|<15; Wherein, F represents the equivalent focal length of the lens, FB represents the equivalent focal length of the rear group lens group, FM represents the equivalent focal length of the middle group lens group, and FF represents the equivalent focal length of the front group lens group , FC represents the equivalent focal length of the second lens group. Projection apparatus according to any one of claims 8 to 12, wherein, The throw ratio of the lens is any value in the range of 0.2 to 0.3; The first lens group and the second lens group satisfy the following relationship: 1.0<L1/L2<1.4; The rear working distance of the lens satisfies the following relationship: 0.15<BFL/L2<0.35; Wherein, L1 represents the total length of the first lens group, L2 represents the distance between the first lens group and the second lens group, and BFL represents the back working distance of the lens. The projection device according to claim 1, wherein the first lens group comprises: Front group mirror group; middle lens group; and The rear group lens group, the rear group lens group, the middle group lens group and the front group lens group are sequentially arranged along the direction away from the optical machine, and the rear group lens group includes a fifth sub-lens group , the fifth sub-lens group is a triplet lens group, and the fifth sub-lens group is configured to improve spherical aberration of different spectra in the lens, and to correct coma and astigmatism of the lens. The projection device according to claim 14, wherein the rear group lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens , the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens along The directions close to the second lens group are arranged in sequence; wherein The diopters of the first lens, the third lens, the fifth lens and the eighth lens are positive numbers, and the second lens, the fourth lens, the sixth lens and the first lens The diopters of the seven lenses are negative; The second lens, the third lens and the fourth lens are cemented together to form the fifth sub-lens group, and the third lens has a lower refractive index than the second lens and the fourth lens The refractive index, the Abbe number of the third lens is greater than the Abbe number of the second lens and the fourth lens; The first lens is an aspheric lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens The lenses are respectively spherical lenses. The projection device according to claim 14, wherein the middle group mirror group comprises: The ninth lens is a spherical lens, and the diopter of the ninth lens is a positive number. The projection device according to claim 14, wherein the front group lens group comprises a tenth lens, an eleventh lens, a twelfth lens and a thirteenth lens, the tenth lens, the eleventh lens , the twelfth lens and the thirteenth lens are sequentially arranged along a direction close to the second lens group; wherein The diopter of the tenth lens is a positive number, and the diopter of the eleventh lens, the twelve lens, and the thirteenth lens is a negative number; The tenth lens and the eleventh lens are spherical lenses, and the twelfth lens and the thirteenth lens are aspherical lenses. The projection device according to any one of claims 14 to 17, wherein the equivalent focal length of the lens, the equivalent focal length of the rear group lens group, the equivalent focal length of the middle group lens group, the The equivalent focal length of the front group lens group and the equivalent focal length of the second lens group satisfy the following relationship: 1<|FB/F|<15; 10<|FM/F|<25; 10<|FF/F|<25; 5<|FC/F|<15; Wherein, F represents the equivalent focal length of the lens, FB represents the equivalent focal length of the rear group lens group, FM represents the equivalent focal length of the middle group lens group, and FF represents the equivalent focal length of the front group lens group , FC represents the equivalent focal length of the second lens group. Projection apparatus according to any one of claims 14 to 18, wherein, The throw ratio of the lens is any value in the range of 0.2 to 0.3; The first lens group and the second lens group satisfy the following relationship: 1.0<L1/L2<1.3; The rear working distance of the lens satisfies the following relationship: 0.1<BFL/L2<0.3; Wherein, L1 represents the total length of the first lens group, L2 represents the distance between the first lens group and the second lens group, and BFL represents the back working distance of the lens. The projection device according to any one of claims 1 to 19, wherein the second lens group comprises a concave reflector, and the concave reflector is an aspheric reflector or a free-form surface reflector.

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