CN118363155B

CN118363155B - Optical lens and near-eye display device

Info

Publication number: CN118363155B
Application number: CN202410802562.1A
Authority: CN
Inventors: 于笑枝; 陈昭聪; 曾昊杰
Original assignee: Jiangxi Lianhao Photoelectric Co ltd
Current assignee: Jiangxi Lianhao Photoelectric Co ltd
Priority date: 2024-06-20
Filing date: 2024-06-20
Publication date: 2024-10-18
Anticipated expiration: 2044-06-20
Also published as: CN118363155A

Abstract

The invention provides an optical lens and near-eye display equipment, which sequentially comprise a first lens, a second lens, a third lens and a fourth lens along the reverse direction of light transmission; the first lens has positive focal power, the light emergent surface of the first lens is a convex surface, and the light incident surface of the first lens is a convex surface; the second lens has negative focal power, the light emergent surface of the second lens is concave at a paraxial region, and the light incident surface of the second lens is convex at a paraxial region; the third lens has negative focal power, the light emergent surface of the third lens is a concave surface at a paraxial region, and the light incident surface of the third lens is a concave surface; the fourth lens has positive focal power, the light emergent surface of the fourth lens is convex, and the light incident surface of the fourth lens is concave. The optical lens provided by the invention has the advantages of larger angle of view, shorter total optical length, larger image plane, higher resolution, excellent imaging quality and excellent sensory experience for users through specific surface shape setting and reasonable focal power distribution.

Description

Optical lens and near-eye display device

Technical Field

The present invention relates to the field of imaging lenses, and in particular, to an optical lens and a near-eye display device.

Background

With the gradual expansion of application range and scene of VR (virtual reality) technology and the wide application of VR technology in various fields of scientific research, military, industry, games, video, education and the like, VR head-mounted equipment is urgently required to be an optical engine with large field angle and light weight, so that the technical level requirements of projection optical lens products on imaging quality, optical distortion, field angle, volume and the like are increasingly improved.

The projection lens of the optical engine of the VR head-mounted device popular in the market at present has a smaller field angle, so that imaging pictures in a large field of view are difficult to obtain, and the actual requirements cannot be met; the number of lenses of many projection lenses is large, so that the cost and the volume of the lenses are high, and the projection lenses are not beneficial to popularization and application in the market.

Disclosure of Invention

In view of the foregoing, it is an object of the present invention to provide an optical lens having one or more advantages of a large angle of view, a high pixel, excellent imaging quality, and the like.

The invention adopts the technical scheme that:

An optical lens sequentially comprises a first lens, a second lens, a third lens and a fourth lens along the reverse direction of light transmission; the first lens, the second lens, the third lens and the fourth lens respectively comprise a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are oppositely arranged on the surface of each lens; the first lens has positive focal power, the light emergent surface of the first lens is a convex surface, and the light incident surface of the first lens is a convex surface; the second lens has negative focal power, the light emergent surface of the second lens is concave at a paraxial region, and the light incident surface of the second lens is convex at the paraxial region; the third lens has negative focal power, the light emergent surface of the third lens is a concave surface at a paraxial region, and the light incident surface of the third lens is a concave surface; the fourth lens has positive focal power, the light emergent surface of the fourth lens is a convex surface, and the light incident surface of the fourth lens is a concave surface; wherein, the radian θ of the effective focal length f of the optical lens and the maximum half field angle of the optical lens satisfies: 30mm/rad < f/θ <40mm/rad.

The invention also provides a near-eye display device, which sequentially comprises the following components along the transmission direction of the optical signal: an image source and the optical lens; the image source is used for emitting an optical signal, and the optical signal comprises image information; the optical lens is arranged in the light emitting direction of the image source, and the fourth lens is arranged closer to the image source than the first lens, and is used for modulating and transmitting light signals sent by the image source to human eyes.

Compared with the prior art, the optical lens provided by the invention has the advantages that through specific surface shape arrangement and reasonable focal power distribution, the optical lens has a larger visual field angle and a shorter total optical length, the thinning of near-eye display equipment is facilitated, the larger visual field angle can provide a display effect with a wide visual field, and better experience is brought to users; meanwhile, the optical lens also has a larger image surface and higher resolution power, can be matched with a large-size image source to realize high-definition imaging, improves imaging quality, and brings excellent sensory experience for users.

Drawings

The foregoing and/or additional aspects and advantages of the invention will become apparent and may be better understood from the following description of embodiments taken in conjunction with the accompanying drawings in which:

Fig. 1 is a schematic structural diagram of a near-eye display device according to an embodiment of the present invention.

Fig. 2 is a schematic structural diagram of an optical lens provided in embodiment 1 of the present invention.

Fig. 3 is an astigmatic curve diagram of an optical lens provided in embodiment 1 of the present invention.

Fig. 4 is an f- θ distortion graph of the optical lens provided in embodiment 1 of the present invention.

Fig. 5 is a schematic structural diagram of an optical lens provided in embodiment 2 of the present invention.

Fig. 6 is an astigmatic curve diagram of an optical lens provided in embodiment 2 of the present invention.

Fig. 7 is an f- θ distortion graph of the optical lens provided in embodiment 2 of the present invention.

Fig. 8 is a schematic structural diagram of an optical lens provided in embodiment 3 of the present invention.

Fig. 9 is an astigmatic curve diagram of an optical lens provided in embodiment 3 of the present invention.

Fig. 10 is an f- θ distortion graph of an optical lens provided in embodiment 3 of the present invention.

Fig. 11 is a schematic view of an optical path of a near-eye display device provided in embodiment 4 of the present invention.

The invention will be further described in the following detailed description in conjunction with the above-described figures.

Detailed Description

For a better understanding of the application, various aspects of the application will be described in more detail with reference to the accompanying drawings. It should be understood that these detailed description are merely illustrative of embodiments of the application and are not intended to limit the scope of the application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.

It should be noted that in the present specification, the expressions of first, second, third, etc. are only used to distinguish one feature from another feature, and do not represent any limitation on the feature. Accordingly, a first lens discussed below may also be referred to as a second lens or a third lens without departing from the teachings of the present invention.

In the drawings, the thickness, size, and shape of the lenses have been slightly exaggerated for convenience of explanation. In particular, the spherical or aspherical shape shown in the drawings is shown by way of example. That is, the shape of the spherical or aspherical surface is not limited to the shape of the spherical or aspherical surface shown in the drawings. The figures are merely examples and are not drawn to scale.

Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, then the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region.

It will be further understood that the terms "comprises," "comprising," "includes," "including," "having," "containing," and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Furthermore, when a statement such as "at least one of the following" appears after a list of features that are listed, the entire listed feature is modified instead of modifying a separate element in the list. Furthermore, when describing embodiments of the application, use of "may" means "one or more embodiments of the application. Also, the term "exemplary" is intended to refer to an example or illustration.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

It should be noted that, without conflict, the embodiments of the present application and features of the embodiments may be combined with each other. The application will be described in detail below with reference to the drawings in connection with embodiments.

The invention provides an optical lens, which is used for modulating an optical signal emitted by an image source and transmitting the optical signal to the human eye entrance pupil side, wherein the optical lens is arranged in the light emitting direction of the image source, namely, the emitting surface of the image source is the light emitting side of the optical signal. The lens assembly comprises a first lens, a second lens, a third lens and a fourth lens in sequence along the opposite direction of light transmission (namely from the human eye entrance pupil side to the image source surface), and an air gap is reserved between any two adjacent lenses. The first lens, the second lens, the third lens and the fourth lens respectively comprise a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are oppositely arranged on the surface of each lens. It will be appreciated that the surface of each lens that is close to the image source is referred to as the light entrance surface of the lens, and the surface of each lens that is close to the entrance pupil side of the human eye is referred to as the light exit surface of the lens.

In some embodiments, the first lens has positive optical power, the light exit surface of the first lens is convex, and the light entrance surface of the first lens is convex. The first lens adopts a positive focal power lens, so that light rays can be converged into human eyes more quickly, the total length of the system is reduced, and the miniaturization of the system is better realized. The second lens has negative focal power, the light emergent surface of the second lens is concave at a paraxial region, and the light incident surface of the second lens is convex at the paraxial region. The third lens has negative focal power, the light emergent surface of the third lens is a concave surface at the paraxial region, and the light incident surface of the third lens is a concave surface. The third lens adopts a biconcave lens, so that aberration and distortion brought by a previous system can be effectively corrected, and the imaging quality of the lens is improved. The fourth lens has positive focal power, the light emergent surface of the fourth lens is convex, and the light incident surface of the fourth lens is concave.

In some embodiments, the effective focal length f of the optical lens and the radian θ of the maximum half field angle of the optical lens satisfy: 30mm/rad < f/θ <40mm/rad. The lens has larger focal length and larger angle of view, can realize the balance of high pixels and large angle of view, and can realize the effect of approaching to the field of view of human eyes, thereby bringing better visual experience to users.

In some embodiments, the optical total length TTL of the optical lens and the display area length IH of the image source to which the optical lens can be matched satisfy: 1.1< TTL/IH <1.5. The optical lens meets the conditions, is beneficial to controlling the total optical length of the optical lens, and can be matched with an image source with a larger size to realize high-definition imaging, so that excellent sensory experience is brought to users.

In some embodiments, the effective focal length f of the optical lens and the focal length f1 of the first lens satisfy: 1.2< f1/f <2.5. The first lens has larger positive refractive power, more light rays can enter the rear optical system, the whole imaging quality is improved while the angle of view is increased, a larger eye movement range can be provided, and better immersion experience is provided for a user.

In some embodiments, the effective focal length f of the optical lens and the focal length f2 of the second lens satisfy: -30< f2/f < -5; the curvature radius R3 of the light emergent surface of the second lens and the curvature radius R4 of the light incident surface of the second lens satisfy the following conditions: 0.3< R3/R4<0.8. The conditions are met, so that the light rays have smaller emergence angles when exiting the second lens, the distortion of the optical lens is corrected, and the imaging quality of the lens edge view field is improved.

In some embodiments, the effective focal length f of the optical lens and the focal length f3 of the third lens satisfy: -20< f3/f < -3; the curvature radius R5 of the light exit surface of the third lens and the curvature radius R6 of the light entrance surface of the third lens satisfy the following conditions: -3< R5/R6< -0.3. The optical lens meets the conditions, is favorable for realizing better imaging quality of the lens under different diopters, and improves the imaging quality of the optical lens.

In some embodiments, the effective focal length f of the optical lens and the focal length f4 of the fourth lens satisfy: 1.2< f4/f <2.5. The conditions are met, and the fourth lens element with larger positive refractive power can effectively converge light rays emitted from the image source side, so that the image source with larger size can be matched with the image source to realize Gao Qingcheng images.

In some embodiments, the light exit surface radius of curvature R1 of the first lens and the light entrance surface radius of curvature R2 of the first lens satisfy: -0.3< R1/R2<0. The surface type of the first lens is reasonably controlled, so that light rays are favorable to have a larger visual field range after exiting from the first lens, a larger eye movement range is provided, and better immersion experience is provided for a user.

In some embodiments, the optical total length TTL of the optical lens and the back focal length BFL of the optical lens satisfy: 0.22< BFL/TTL <0.3. The lens has larger optical back focus, so that on one hand, light rays emitted from the image source side have larger bending space, the matching adaptability of the optical lens and a large-size image source is improved, meanwhile, a larger space is reserved between the image source and the optical lens, the distance between the image source and the optical lens is convenient to adjust, diopter adjustment in a larger range (from-8D to +5D) can be realized, and the wearing requirements of users with different myopia or hyperopia degrees can be met.

In some embodiments, the center thickness CT1 of the first lens and the center thickness CT2 of the second lens satisfy: 1< CT1/CT2<1.5; the center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy: 3< CT2/CT3<4. The optical thickness of each lens is reasonably set to meet the conditions, so that the lens has good imaging quality under different diopters, and meanwhile, the sensitivity of the optical lens is reduced, and the production yield is improved.

In some embodiments, the focal length f1 of the first lens and the focal length f4 of the fourth lens satisfy: 0.7< f1/f4<1.3; center thickness CT1 of the first lens and center thickness CT4 of the fourth lens: 0.9< CT1/CT4<1.5. The lens has the advantages that the focal length and thickness relations of the head lens and the tail lens are reasonably set, light rays can enter the system at a gentle angle, aberration of the optical system under different diopter conditions can be corrected, imaging quality is improved, and users with different myopia or hyperopia degrees wear the lens with better sensory experience.

In some embodiments, the optical total length TTL of the optical lens and the effective focal length f of the optical lens satisfy: 1.35< TTL/f <1.8. The ratio of the total length to the effective focal length of the optical lens can be reasonably controlled, so that the optical lens has a shorter total length, the volume of the system is effectively reduced, and the optical lens is better carried on VR equipment for use.

In some embodiments, the focal length f1 of the first lens and the focal length f2 of the second lens satisfy: -0.3< f1/f2<0; the focal length f3 of the third lens and the focal length f4 of the fourth lens satisfy: -8< f3/f4< -3; the focal length f2 of the second lens and the focal length f3 of the third lens satisfy: 1< f2/f3<3. The focal length relation of the four lenses is reasonably distributed, so that the turning degree of light rays can be effectively increased, and the system has a larger field angle, thereby realizing the effect of approaching to the field of vision of human eyes; meanwhile, the aberration of the optical system is corrected, and the imaging quality of the optical system is improved.

In some embodiments, the center thickness CT1 of the first lens and the edge thickness ET1 of the first lens satisfy: 2.5< CT1/ET1<3.5. The lens meets the conditions, is beneficial to improving the convergence capacity of light rays with large fields of view, adjusting the focusing position of the light rays, shortening the total optical length and realizing the miniaturization of the lens.

In some embodiments, the center thickness CT2 of the second lens and the edge thickness ET2 of the second lens satisfy: 2.5< CT2/ET2<3.5. The method meets the conditions, is beneficial to the processing and production of the lens and improves the assembly yield.

In some embodiments, the center thickness CT3 of the third lens and the edge thickness ET3 of the third lens satisfy: 0.3< CT3/ET3<0.6. The imaging system meets the conditions, is beneficial to correcting various aberrations of the system and improves the imaging quality.

In some embodiments, the center thickness CT4 of the fourth lens and the edge thickness ET4 of the fourth lens satisfy: 0.9< CT4/ET4<1.6. The deflection angle of the main light can be reasonably controlled to improve the matching degree with a large-size image source.

In some embodiments, the light exit surface radius of curvature R7 of the fourth lens and the light entrance surface radius of curvature R8 of the fourth lens satisfy: 0.5< R7/R8<1.5. The above conditions are met, and the surface shape of the fourth lens is reasonably arranged, so that the improvement of the resolution quality of the paraxial visual field is facilitated, the reduction of the total length of the optical lens is facilitated, and the balance of high imaging quality and miniaturization of the optical lens is realized.

In some embodiments, the optical lens satisfies the conditional expression: 28mm < TTL <35mm,18mm < f <22mm; wherein TTL represents the total optical length of the optical lens, and f represents the effective focal length of the optical lens. The conditions are satisfied, which indicates that the optical lens provided by the embodiment of the invention has at least long focal length characteristics and miniaturization characteristics.

In some embodiments, the lens material in the optical lens provided by the present invention may be glass or plastic. When the lens is made of plastic, the production cost can be effectively reduced. In addition, when the lens is made of glass, the geometrical chromatic aberration of the optical system can be effectively corrected through the characteristic of low chromatic dispersion of the glass. The optical lens provided by the invention can adopt a full plastic lens structure, so that the lens has excellent imaging performance, the structure of the lens is compact, and the miniaturization and the high image quality balance of the lens can be better realized.

In some embodiments, the first lens, the second lens, the third lens and the fourth lens may be spherical lenses or aspherical lenses, and the aspherical structure can effectively reduce the aberration of the optical system compared with the spherical structure, thereby reducing the number of lenses and the size of the lenses, and better realizing miniaturization of the lens. More specifically, the first lens, the second lens, the third lens and the fourth lens can be aspheric lenses, so that the aberration of the optical lens can be effectively reduced, the number of lenses is reduced, the size of the lenses is reduced, and miniaturization of the lens is better realized.

In various embodiments of the present invention, when an aspherical lens is used as the lens, each aspherical surface shape of the optical lens satisfies the following equation:

；

Wherein z is the distance between the curved surface and the curved surface vertex in the optical axis direction, h is the distance between the optical axis and the curved surface, c is the curvature of the curved surface vertex, K is the quadric surface coefficient, B, C, D, E, F, G, H is the fourth-order, sixth-order, eighth-order, tenth-order, fourteen-order and sixteen-order curved surface coefficients respectively.

In addition, the invention also provides near-eye display equipment, which sequentially comprises the following components along the transmission direction of the optical signal: an image source and the optical lens; the image source is for emitting an optical signal, the optical signal comprising image information. The optical lens is arranged in the light emitting direction of the image source, and the fourth lens is arranged closer to the image source than the first lens, and the optical lens is used for modulating and transmitting the light signals sent by the image source to human eyes.

The invention is further illustrated in the following examples. In various embodiments, the thickness, radius of curvature, and material selection portion of each lens in the optical lens may vary, and for specific differences, reference may be made to the parameter tables of the various embodiments. The following examples are merely preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the following examples, and any other changes, substitutions, combinations or simplifications that do not depart from the gist of the present invention are intended to be equivalent substitutes within the scope of the present invention.

Example 1

Referring to fig. 1, a schematic structure diagram of a near-eye display device 400 provided in an embodiment of the present invention is shown, referring to fig. 2, a schematic structure diagram of an optical lens 100 provided in embodiment 1 of the present invention is shown, the optical lens 100 is used for modulating an optical signal emitted from an image source 10 and transmitting the modulated optical signal to an entrance pupil side of a human eye, and the optical lens 100 is disposed in an emitting direction of the image source 10, that is, an emitting surface of the image source 10 is an emitting side of the optical signal. As can be seen from fig. 2, the optical lens 100 sequentially comprises, along the opposite direction of light transmission (i.e., from the human eye entrance pupil side to the image source surface S9): a first lens L1, a second lens L2, a third lens L3, and a fourth lens L4. The first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 each include a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are disposed on the surface of each lens. It will be appreciated that the surface of each lens that is adjacent to the image source 10 is referred to as the light entry surface of the lens, and the surface of each lens that is adjacent to the entrance pupil side of the human eye is referred to as the light exit surface of the lens.

The first lens L1 has positive focal power, the light-emitting surface S1 of the first lens is a convex surface, and the light-entering surface S2 of the first lens is a convex surface;

The second lens L2 has negative focal power, the light emergent surface S3 of the second lens is concave at a paraxial region, and the light incident surface S4 of the second lens is convex at a paraxial region;

the third lens L3 has negative focal power, the light emergent surface S5 of the third lens is a concave surface at a paraxial region, and the light incident surface S6 of the third lens is a concave surface;

the fourth lens L4 has positive focal power, the light emergent surface S7 of the fourth lens is a convex surface, and the light incident surface S8 of the fourth lens is a concave surface;

in order to better realize small volume of the lens and reduce cost, the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4 are all plastic aspheric lenses.

In order to meet wearing requirements of users with different Qu Guangcheng degrees, the adjustment of the optical system between different diopters can be realized by dynamically adjusting the air interval CTw between the whole lens group (comprising the first lens L1, the second lens L2, the third lens L3 and the fourth lens L4) and the image source surface S9 on the optical axis, so that wearing requirements of users with different Qu Guangcheng degrees can be well met.

The relevant parameters of each lens in the optical lens 100 in embodiment 1 are shown in table 1-1.

TABLE 1-1

The surface profile parameters of the aspherical lens of the optical lens 100 in example 1 are shown in tables 1-2.

TABLE 1-2

Referring to fig. 3, an astigmatic diagram of an optical lens 100 is shown, in which the horizontal axis represents the amount of shift (in mm) and the vertical axis represents the angle of view (in degrees). As can be seen from fig. 3, the meridional field curvature and the sagittal field curvature of different wavelengths are within ±0.4mm, which means that the astigmatism of the optical lens 100 is well corrected.

Referring to fig. 4, an f- θ distortion graph of the optical lens 100 is shown, wherein the horizontal axis represents the distortion percentage and the vertical axis represents the angle of view (in degrees). As can be seen from fig. 4, the f- θ distortion at different image heights on the imaging plane is controlled within-6%, which indicates that the distortion of the optical lens 100 is well corrected.

Example 2

Referring to fig. 5, a schematic structural diagram of an optical lens 200 provided in embodiment 2 of the present invention is shown, and the main difference between the present embodiment and embodiment 1 is that: the optical parameters such as the radius of curvature and the lens thickness are different for each lens surface.

The relevant parameters of each lens in the optical lens 200 in example 2 are shown in table 2-1.

TABLE 2-1

The surface profile parameters of the aspherical lens of the optical lens 200 in example 2 are shown in table 2-2.

TABLE 2-2

Referring to fig. 6, an astigmatic diagram of the optical lens 200 is shown, and as can be seen from fig. 6, both the meridional field curvature and the sagittal field curvature of different wavelengths are within ±0.4mm, which indicates that the astigmatism of the optical lens 200 is well corrected.

Referring to fig. 7, an f- θ distortion graph of the optical lens 200 is shown, and as can be seen from fig. 7, the f- θ distortion at different image heights on the imaging plane is controlled within-6%, which indicates that the distortion of the optical lens 200 is well corrected.

Example 3

Referring to fig. 8, a schematic structural diagram of an optical lens 300 provided in embodiment 3 of the present invention is shown, and the main difference between the present embodiment and embodiment 1 is that: the optical parameters such as the radius of curvature and the lens thickness are different for each lens surface.

The relevant parameters of each lens in the optical lens 300 in example 3 are shown in table 3-1.

TABLE 3-1

The surface profile parameters of the aspherical lens of the optical lens 300 in example 3 are shown in table 3-2.

TABLE 3-2

Referring to fig. 9, an astigmatic diagram of the optical lens 300 is shown, and as can be seen from fig. 9, both the meridional field curvature and the sagittal field curvature of different wavelengths are within ±0.6mm, which indicates that the astigmatism of the optical lens 300 is well corrected.

Referring to fig. 10, an f- θ distortion graph of the optical lens 300 is shown, and as can be seen from fig. 10, the f- θ distortion at different image heights on the imaging plane is controlled within-6%, which indicates that the distortion of the optical lens 300 is well corrected.

Referring to table 4, the optical characteristics corresponding to the above embodiments include the effective focal length f, the total optical length TTL, the aperture value Fno, the maximum field angle FOV, the exit pupil distance ED, the entrance pupil diameter EPD, and the display area length IH of the image source that the optical lens can match with the values corresponding to each conditional expression in the embodiments.

TABLE 4 Table 4

In summary, the optical lens provided by the present invention has at least the following advantages:

(1) Through specific surface shape setting and reasonable focal power distribution, the optical lens has a larger field of view angle (FOV is more than or equal to 70 ℃) and a shorter total optical length (TTL is less than 32.1 mm), which is beneficial to the light and thin of near-eye display equipment, and the larger field of view angle can provide a display effect with a wide field of view, thereby bringing better experience to users.

(2) The optical axis optical lens system has the advantages that the space interval distance between the lens group and the image source on the optical axis can be adjusted, different diopter adjustment (-8D to +5D) can be achieved, the imaging quality is high, the requirements of different myopic users can be met, meanwhile, the exit pupil distance (ED >12.5 mm) is large, and better experience feeling can be provided for the users.

(3) The optical lens also has a larger image surface, smaller distortion (distortion is within-6%) and higher resolution, can be matched with a large-size image source to realize high-definition imaging, and brings excellent sensory experience for users.

Example 4

Referring to fig. 11, an optical path diagram of a near-eye display device 400 according to an embodiment of the application is shown, where the near-eye display device 400 includes an image source 10 and an optical lens (e.g., the optical lens 100) according to any of the foregoing embodiments of the application, and the optical lens 100 is located between a human eye 20 and the image source 10. The image information sent from the image source 10 enters the human eye 20 through the optical lens 100 to be imaged, and a high-definition amplified virtual image can be observed in the human eye 20, so that the human eye has a very realistic sensory experience.

The image source 10 is arranged to emit an optical signal comprising image information. Specifically, the image source 10 may be one of Micro LEDs, OLED, LCD, LCOS, M-OLED, etc., and more specifically, in this embodiment, the image source 10 may use a Micro OLED display screen of 1.3 inches, which can provide high-definition image information for the optical lens 100.

The optical lens 100 is disposed in the light emitting direction of the image source 10, and the fourth lens in the optical lens 100 is disposed closer to the image source 10 than the first lens, and the optical lens 100 is configured to modulate and transmit the light signal emitted from the image source 10 to the human eye 20.

The near-eye display device 400 may be VR glasses, VR helmets, head-mounted display devices, and the like, and the optical lens has a larger viewing angle and a shorter total optical length, so that the near-eye display device is favorable for lightening and thinning the near-eye display device, the larger viewing angle can provide a display effect with a wide viewing field, and the immersion sense of a user is improved, so that better experience is brought to the user, and meanwhile, the optical lens also has a larger exit pupil distance, a larger image plane and higher resolution power, and the optical signal image modulated by the optical lens is bright and clear, has a better effect, and projects a clearer picture to human eyes, so that the near-eye display device with the optical lens has the characteristics of miniaturization, wide viewing field and high image quality, and can effectively improve the visual experience and comfort of the user.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The foregoing examples illustrate only a few embodiments of the invention and are described in detail herein without thereby limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. The optical lens comprises a first lens, a second lens, a third lens and a fourth lens in sequence along the reverse direction of light transmission; the first lens, the second lens, the third lens and the fourth lens respectively comprise a light incident surface and a light emergent surface, and the light incident surface and the light emergent surface are oppositely arranged on the surface of each lens;

The first lens has positive focal power, the light emergent surface of the first lens is a convex surface, and the light incident surface of the first lens is a convex surface;

The second lens has negative focal power, the light emergent surface of the second lens is concave at a paraxial region, and the light incident surface of the second lens is convex at the paraxial region;

the third lens has negative focal power, the light emergent surface of the third lens is a concave surface at a paraxial region, and the light incident surface of the third lens is a concave surface;

the fourth lens has positive focal power, the light emergent surface of the fourth lens is a convex surface, and the light incident surface of the fourth lens is a concave surface;

Wherein, the radian θ of the effective focal length f of the optical lens and the maximum half field angle of the optical lens satisfies: 30mm/rad < f/θ <40mm/rad; the total optical length TTL of the optical lens and the display area length IH of the image source that the optical lens can match satisfy: 1.1< TTL/IH <1.5.

2. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f1 of the first lens satisfy: 1.2< f1/f <2.5.

3. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f2 of the second lens satisfy: -30< f2/f < -5; the curvature radius R3 of the light exit surface of the second lens and the curvature radius R4 of the light entrance surface of the second lens satisfy the following conditions: 0.3< R3/R4<0.8.

4. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f3 of the third lens satisfy: -20< f3/f < -3; the curvature radius R5 of the light exit surface of the third lens and the curvature radius R6 of the light entrance surface of the third lens satisfy the following conditions: -3< R5/R6< -0.3.

5. The optical lens of claim 1, wherein an effective focal length f of the optical lens and a focal length f4 of the fourth lens satisfy: 1.2< f4/f <2.5.

6. The optical lens of claim 1, wherein a light exit surface curvature radius R1 of the first lens and a light entrance surface curvature radius R2 of the first lens satisfy: -0.3< R1/R2<0.

7. The optical lens of claim 1, wherein an optical total length TTL of the optical lens and a back focal length BFL of the optical lens satisfy: 0.22< BFL/TTL <0.3.

8. The optical lens of claim 1, wherein a center thickness CT1 of the first lens and a center thickness CT2 of the second lens satisfy: 1< CT1/CT2<1.5; the center thickness CT2 of the second lens and the center thickness CT3 of the third lens satisfy: 3< CT2/CT3<4.

9. The optical lens of claim 1, wherein a focal length f1 of the first lens and a focal length f4 of the fourth lens satisfy: 0.7< f1/f4<1.3; a center thickness CT1 of the first lens and a center thickness CT4 of the fourth lens: 0.9< CT1/CT4<1.5.

10. A near-eye display device characterized by comprising, in order along an optical signal transmission direction: an image source, an optical lens as claimed in any one of claims 1 to 9;

The image source is used for emitting an optical signal, and the optical signal comprises image information;

The optical lens is arranged in the light emitting direction of the image source, and the fourth lens is arranged closer to the image source than the first lens, and is used for modulating and transmitting light signals sent by the image source to human eyes.