KR20170133936A - Light source device and projector comprising the same - Google Patents

Abstract

The present invention provides a light source device for emitting light of at least three colors, comprising a first light source module for emitting red light, wherein the first light source module converts the wavelength of the excitation light to emit red light A phosphor substrate including a phosphor layer, a first excitation light source for emitting a first excitation light to the phosphor substrate, and a second excitation light source for emitting a second excitation light to the phosphor substrate. Device.

Description

TECHNICAL FIELD [0001] The present invention relates to a light source device and an image projection device including the light source device.

The present invention relates to a light source apparatus and an image projection apparatus including the same.

As the information age rapidly develops, the importance of a display device that realizes a large screen is emphasized. As an example of a device for realizing such a large screen, there is a projector having a function of enlarging and projecting an image.

Such a projector is becoming increasingly smaller and lighter in weight, and currently, miniature projectors such as a mini projector and a pico projector are being researched and developed.

In such a trend, the optical system of the conventional projector uses a red LED, a green LED, and a blue LED as light sources.

1 is a view showing an optical system of an image projecting apparatus including a conventional light source apparatus, specifically showing an optical system of an image projecting apparatus using a reflective display.

1, the conventional image projection apparatus 1 includes a red light source module 11 (which may include, for example, a red LED 11a) as a light source, a green light source module 13 (Which may include, for example, a green LED 13a) and a blue light source 12 (which may include a blue LED 12a, for example).

However, when the red LED 11a is included as a light source, the following problems may occur.

2A is a graph showing the thermal characteristics of a red LED, wherein an X axis indicates a junction temperature (Tj), and a Y axis indicates a light amount based on 25 deg.

As shown in FIG. 2A, since the amount of light is fixed by the junction temperature of the LED, the junction temperature of the LED must be maintained at 45 ° C or lower in order to maintain the light amount of the red LED at 80% or more based on 25 ° C.

Therefore, since the red LED needs to be cooled well, a large-capacity cooling apparatus is required for the image projection apparatus to satisfy such a cooling condition, and accordingly, a large-capacity fan is required.

In the case of the conventional image projection apparatus 1, there is a limit to the downsizing and lightening of the image projection apparatus, and vibration and noise are inevitably generated due to driving of the large-capacity fan.

Therefore, there is a need for a technique for effectively solving such a problem.

An object of the present invention is to provide a light source device capable of securing a maximum amount of light even in an environment using a low-capacity cooling device, and an image projection device including the same.

The present invention provides a light source device for emitting light of at least three colors, comprising a first light source module for emitting red light, wherein the first light source module converts the wavelength of the excitation light to emit red light A phosphor substrate including a phosphor layer, a first excitation light source for emitting a first excitation light to the phosphor substrate, and a second excitation light source for emitting a second excitation light to the phosphor substrate. Device.

According to one embodiment, the first excitation light source is disposed on one surface of the phosphor substrate and irradiates the first excitation light to the phosphor substrate, and the second excitation light source is disposed on the other surface of the phosphor substrate So that the second excitation light can be irradiated to the phosphor substrate.

According to an embodiment, the first excitation light source may be a blue light emitting diode and the second excitation light source may be a blue laser diode.

According to an embodiment, there is further provided a red dichroic mirror disposed on a light path of the second excitation light source, wherein the red dichromatic mirror reflects red light emitted by the phosphor layer to the outside of the light source device Can be reflected.

The apparatus may further include a light combining module for combining the first excitation light and the second excitation light and irradiating the synthesized light to the phosphor substrate.

According to an embodiment, the light source device may further include a second light source module for emitting green light and a third light source module for emitting blue light.

The present invention also provides an image projection apparatus including the light source device and an image conversion device for forming an image using light incident from the light source device.

According to one embodiment, the image converting apparatus may use any one of a reflective display panel, a transmissive display panel, and a DLP (Digital Light Processor) display panel.

According to the present invention, it is possible to stabilize the thermal characteristics of the LED, especially the red LED, even at a high temperature, so that the maximum amount of light can be ensured even in an environment using a low-capacity cooling device.

In addition, according to an embodiment of the present invention, it is possible to satisfy the insufficient optical power of one excitation light source, and at the same time, it is possible to provide an excitation light source having a color (blue and / or green) Even if the same optical characteristics are made the same, the size of the light source module can be downsized and the product cost can be lowered.

1 is a view showing an optical system of an image projection apparatus including a conventional light source apparatus.
2A is a graph showing the thermal characteristics of a red LED.
2B is a graph showing the thermal characteristics of the green LED.
2C is a graph showing the thermal characteristics of the blue LED.
3A is a diagram showing an optical system of an image projection apparatus including a light source device in which a conventional problem is solved.
3B is a view illustrating an optical system of an image projection apparatus including a light source device according to an embodiment of the present invention.
3C is a diagram illustrating an optical system of an image projection apparatus including a light source device according to another embodiment of the present invention.
4 is a graph showing the thermal characteristics of a blue ELD.
5A and 5B are illustrations of a phosphor substrate.
6 is a conceptual view of a phosphor substrate.
7A is a graph showing the transmittance of the red dichroic mirror according to light wavelengths.
7B is a view showing a light path for each color which transmits or reflects a red dichromatic mirror.
8A is a graph showing the transmittance of blue dichroic mirrors by light wavelength.
8B is a view showing a light path for each color that transmits or reflects a blue dichromatic mirror.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein like reference numerals are used to designate identical or similar elements, and redundant description thereof will be omitted. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role. In the following description of the embodiments of the present invention, a detailed description of related arts will be omitted when it is determined that the gist of the embodiments disclosed herein may be blurred. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. , ≪ / RTI > equivalents, and alternatives.

Terms including ordinals, such as first, second, etc., may be used to describe various elements, but the elements are not limited to these terms.

The terms are used only for the purpose of distinguishing one component from another.

It is to be understood that when an element is referred to as being "connected" or "connected" to another element, it may be directly connected or connected to the other element, . On the other hand, when an element is referred to as being "directly connected" or "directly connected" to another element, it should be understood that there are no other elements in between.

The singular expressions include plural expressions unless the context clearly dictates otherwise.

In this specification, the terms "comprises" or "having ", and the like, are intended to specify the presence of stated features, integers, steps, operations, elements, parts, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

The applicant of the present invention has filed a patent application No. 10-2015-0156916 filed on November 19, 2015 for a light source device and an image projection device including the light source device which solve the conventional problem. For better understanding of the present invention, a description thereof will be given. A specific embodiment is shown in FIG. 3A.

3A is a diagram showing an optical system of an image projection apparatus including a light source device in which a conventional problem is solved.

As shown in FIG. 3A, the image projection apparatus 100 may include light source devices 110, 120, and 130. FIG.

The light source devices 110, 120, and 130 may include at least one light source capable of outputting light of different wavelengths. The light source may be a light emitting diode (LED), but not limited thereto, a laser, a laser diode (LD), an organic light emitting diode (OLED), a non-solid light source, an ultra high pressure (UHP) Lamp. At this time, the light source devices 110, 120, and 130 may further include at least one condenser lens for collecting light from at least one light source.

The light source devices 110, 120 and 130 include a first light source module 110 for emitting red light, a second light source module 120 for emitting blue light, and a third light source module 130 for emitting green light can do.

The first light source module 110 may include an excitation light source 111 and a phosphor substrate 112 to emit excitation light to solve the above-described conventional problems.

The excitation light source 111 may be a UV light source, a blue light emitting diode (LED), a laser diode (LD), or the like using an InGaN-based material. According to one embodiment, the excitation light source 111 is preferably a blue laser diode.

The thermal characteristics of the blue laser diode (or blue ELD) are such that as the temperature Tc increases, the blue laser diode generates a current for applying the same light amount Po to the blue laser diode (If) is changed, it is not impossible to reach the maximum amount of light output by the blue laser diode.

The phosphor substrate 112 includes a phosphor layer (not shown) that converts the wavelength of the excitation light to emit red light, and can convert the wavelength of the light incident from the excitation light source 111 into visible light.

The phosphor layer is a layer formed by applying a phosphor to at least a part of a transparent substrate (see FIG. 5A), or a powdery phosphor mixed with an organic binder such as silicon is cured to form a predetermined shape (See FIG. 5B).

(N, O) 8: Eu, (Ca, Sr, Ba) Si (N, O) 2: Eu is used for converting excitation light into red light, (Ca, Sr) S: Eu, (La, Y) 2O2S: Eu, K2SiF6: Mn, Eu, (Ca, Sr, Ba) AlSi CaAlSiN: Eu can be used.

6, the first light source module 110 emits red light using the blue laser diode 111 and the phosphor substrate 112, so that the thermal characteristics of the light source are stabilized even at a high temperature, The maximum light amount of the light source can be secured even when a low-capacity cooling device is used.

At least one of the second light source module 120 and the third light source module 130 may convert the excitation light source and the wavelength of the excitation light into visible light of blue or green, The second light source module 120 and the third light source module 130 may each include a light source such as a light emitting diode (LED) that emits green and blue visible light.

This is because, as shown in Figs. 2B and 2C, the green LED and the blue LED are stable even at a high temperature.

2B and 2C are graphs showing the thermal characteristics of the green LED and blue LED, respectively. As shown in FIGS. 2B and 2C, unlike the red LED (see FIG. 2A), the green LED and the blue LED have a junction temperature of 120 ° C. Even if it is 90% or more of the luminous intensity of the LED at 25 ° C.

Therefore, it is preferable that the second light source module 120 and the third light source module 130 have no additional configuration like the phosphor substrate 112 like the first light source module 110.

1st Example  (First light source module)

3A, when the first light source module 110 includes one blue ELD 111, two or more ELDYs are required when the optical power of one ELD 111 is small .

3B, the first light source module 110 includes a first excitation light source 114a for emitting excitation light to the phosphor substrate 112, and a second excitation light source 114b for emitting excitation light to the phosphor substrate 112. [ 0.0 > 114b. ≪ / RTI >

At this time, the light combining module 115 may further include a light combining module 115 for combining the first excitation light and the second excitation light emitted from the first excitation light source 114a and the second excitation light source 114b.

The optical synthesizing module 115 may include a polarizing beam splitter (PBS), so that excitation light having an increased optical power than one eld can be irradiated to the phosphor substrate 112.

Since an emission size and an emission angle of a laser diode (LD) are smaller than an LED (Light Emitting Diode), an amount of light emitted by the fluorescent substrate 112 may be smaller than an amount of light when the LED is used have.

Accordingly, when the first light source module 110 includes the blue ELD 111, the first light source module 110 may include a second and a third light source module 120 using LEDs according to an embodiment of the present invention. Specifically between the blue ELD 111 and the phosphor substrate 112, that is, between the blue ELD 111 and the blue ELD 111 in order to make the same characteristics (light emission size and emission angle, etc.) 111) front surface or a front surface of the light combining module 115, a diffusing optical system 113 including at least one lens for evenly spreading excitation light.

In the case of the light source apparatus according to the first embodiment, there is a limitation in downsizing the optical system of the first light source module 111 due to the volume occupied by the diffusing optical system 113 or the optical combining module 115, There is a problem that the product unit price rises.

Second Example  (First light source module)

3C shows an optical system of an image projection apparatus including a light source device according to another embodiment of the present invention, which solves the problems of the foregoing embodiments.

As shown in FIG. 3C, the first light source module 110 may include a first excitation light source 116a and a second excitation light source 116b.

In this case, the first excitation light source 116a may be a UV light source, a blue light emitting diode, a laser diode, or the like as described above as the light source for irradiating the first excitation light to the phosphor substrate 112, It is preferable that the blue light emitting diode is the same as the light emitting diode 12 (see Fig. 1). Accordingly, the first light source module 110 has the same characteristics as those of the light emitting diodes included in the second and third light source modules 120 and 130 (for example, the light emission size and the light emission angle) The size of the first light source module 110 can be reduced because the diffusing optical system 113 is not required. Further, as shown in FIG. 2C, it is needless to say that the blue light emitting diode can secure the maximum light amount because the thermal characteristics are stable even at a high temperature.

Meanwhile, the first light source module 110 may further include a second excitation light source 116b for solving an insufficient optical power with only one excitation light source. The second excitation light source 116b may be a UV light source, a blue light emitting diode, a laser diode, or the like as the light source for irradiating the second excitation light to the phosphor substrate 112, but is preferably a blue laser diode .

At this time, the first excitation light source 116a is positioned on one surface of the phosphor substrate 112 to emit first excitation light to the phosphor substrate 112 of the first surface, and the second excitation light source 116b emits the first excitation light to the phosphor substrate 112 to irradiate the phosphor substrate 112 of the other surface with the second excitation light.

More specifically, according to an embodiment of the present invention, when a red dichroic mirror is included to output red light emitted by the first light source module 110 to the outside of the light source device, The second excitation light source 116b may be disposed such that the red dichromatic mirror 210 is positioned on the optical path where the excitation light is formed from the second excitation light source 116b to the phosphor substrate 112. [

That is, the first excitation light source 116a and the second excitation light source 116b are disposed to face each other with the phosphor substrate 112 therebetween, and the second excitation light is transmitted through the red dichromatic mirror 210 to the phosphor substrate 112 and the first excitation light can reach the phosphor substrate 112 without passing through the red dichroic mirror 210. [

Accordingly, the red light emitted by the phosphor substrate 112 is reflected by the red dichroic mirror 210 and can be emitted to the outside of the light source device.

The first light source module 110 includes the phosphor substrate 112, the first excitation light source 116a, and the second excitation light source 116b, and includes a diffusing optical system 113, Module 115 is not an essential component, it is possible to reduce the size of the optical system, lower the product cost, and solve the optical power problem that has the same optical characteristics as other color light sources, but is insufficient.

Image projection device

Hereinafter, an image projection apparatus including the light source apparatus described in the foregoing embodiments will be described, but the description overlapping with the preceding description will be omitted and the description will be omitted.

3A, 3B, or 3C, an image projection apparatus including a light source apparatus according to an exemplary embodiment of the present invention may include a color combining unit 200, an illumination system 300, And a projection lens unit 400 may be included.

However, it is needless to say that the components shown in Figs. 3A, 3B or 3C are not essential, so that an image projection apparatus having components having more or fewer components can be implemented.

Hereinafter, each component will be described.

The description of the light source devices 110, 120, and 130 will be omitted.

According to an embodiment of the present invention, the light source apparatuses 110, 120, and 130 may further include a color combination unit 200.

The color combining unit 200 is a means for combining at least two colors and is disposed between the light source devices 110, 120 and 130 and the illumination system 300 including the image conversion device, To the image conversion device.

That is, the color combining unit 200 may be colored light or white light having two or more different colors combined, and the light irradiated by the plurality of light source modules may be cross-output light according to time. At this time, it is needless to say that the light output by the color combining unit 200 is not limited to visible light, but may be infrared light or ultraviolet light.

The color combining section 200 may include at least two or more dichroic mirrors as shown in Figures 3A to 3C and may include a red dichroic mirror 210 and a blue dichroic mirror 220 according to one embodiment. .

FIG. 7A is a graph showing the transmittance of the red dichroic mirror 210 and the blue dichroic mirror 220 according to light wavelengths of the red dichromatic mirror, An optical path is shown in Fig. 7B.

As shown in FIGS. 7A and 7B, the red dichroic mirror 210 transmits or reflects light according to the wavelength of the incident light, so that the red light transmits the reflection, blue, and green depending on the color.

8A is a graph showing the transmittance of the blue dichroic mirror at each light wavelength, and FIG. 8B is a view showing a light path of each color transmitting or reflecting the blue dichromatic mirror, wherein blue transmits reflection, red and green .

The red dichroic mirror 210 and the blue dichroic mirror 220 are arranged such that light illuminated by the third light source module 130 illuminates the red dichroic mirror 210 and the blue dichroic mirror 220 The first light source module 110 and the second light source module 120 may be disposed side by side on the optical path of the third light source module 130 regardless of the order so that the light is emitted outside the light source device. The red dichroic mirror 210 and the blue dichromatic mirror 220 are respectively incident on the red dichroic mirror 210 and the blue dichroic mirror 220 so that red and blue are emitted from the light source unit. As shown in FIG.

It is needless to say that the color combination and arrangement of the dichroic mirror is not limited to this, and it is of course possible to include different kinds of dichroic mirrors depending on the arrangement of the light source modules, or the arrangement thereof may be different.

The illumination system 300 may include an image conversion device and may be configured to form an image using light incident from the light source devices 110, 120, and 130. At this time, the image conversion device can perform color conversion or color separation on the light incident from the light source devices 110, 120 and 130, for example, and convert the light into an image using the display device.

The image converting apparatus can use various methods for giving images to light. For example, the image converting apparatus can use any one of a reflective display panel (e.g., LCOS), a transmissive display panel (e.g., HTPS-LCD), and a DLP have.

Hereinafter, it will be described based on the case where the illumination system 300 uses the reflective display panel 350, but the scope of the present invention is not intended to be limited thereto.

The illumination system 300 includes a fly's eye array (FEA) that optically homogenizes the light emitted from the color combination unit 200 to improve illumination and color uniformity with respect to light emitted from the color combination unit 200, : Fly's Eye Array 310). The fly eye array may be a square in which a plurality of convex micro lenses are arrayed. A fly eye array in which a plurality of micro lenses are arranged may include an objective array arranged in the order in which light from the light source is incident, array and a field array.

When the reflective display panel 350 is used in the image conversion apparatus, the illumination system 300 is provided with a polarizing plate 300 for reducing light loss on one side (specifically, the display panel side) of the fly's eye array 310, The conversion device 320 may further be included. The polarized light conversion apparatus may be constituted by a polarizing beam splitter array (PBSA) comprising a plurality of polarizing beam splitters arranged in parallel, and the polarizing beam splitter array includes a polarizing separation film and a retardation plate (1/2?) . Each polarization splitting film of the polarizing beam splitter array may pass, for example, P polarized light among the light from the fly's eye lens 310 and change the S polarized light to 90 degrees. The S-polarized light whose optical path has been changed is reflected by the adjacent polarization splitting film and is output as it is, and the P-polarized light transmitted through the polarization splitting film is converted into S-polarized light by the phase difference plate provided on the front side (light output side) That is, according to one example, the light from the fly's eye lens 310 can be polarized into S polarized light.

Accordingly, the illumination system 300 transmits the light emitted from the polarizing beam splitter array to the reflective display panel 350, enters the light having the image formed by the reflective display panel 350, 400, as shown in FIG.

On the other hand, the DMD of the reflective display panel does not use polarized light, so that the polarization beam splitter array is not used, and may include only a fly's eye array. The beam splitter cube 360 may be replaced with a total internal reflection prism that separates the path of the beam according to the angle.

The projection lens unit 400 can enlarge and project the image input from the polarization beam splitter cube 360, such as an external screen, to the illumination system 300 in detail.

As described above, the present embodiment is based on the case where the illumination system 300 uses an image conversion apparatus using a reflection type display panel, but the scope of the present invention is not limited to this, and the transmissive display panel, The present invention can be applied to a light source device using different colors as a light source and an image projection device including the same.

The preferred embodiments of the present invention have been described in detail with reference to the drawings. It will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing detailed description, and all changes or modifications derived from the meaning, range, and equivalence of the claims are included in the scope of the present invention Should be interpreted.

110, 120, 130: light source device 110: first light source module
111, 114a, 114b: excitation light source 116a: first excitation light source
116b: second excitation light source 112: phosphor substrate
113: diffusion optical system 115: optical combining module
120: second light source module 130: third light source module
200: Color combining unit 300: Illumination system
310: fly's eye array 320: polarized light conversion device
350: reflective display panel 360: polarizing beam splitter cube
400: projection lens unit

Claims (8)

A light source device for emitting light of at least three colors,
A first light source module for emitting red light;
≪ / RTI >
The first light source module includes:
A phosphor substrate including a phosphor layer that converts a wavelength of excitation light to emit red light;
A first excitation light source for emitting a first excitation light to the phosphor substrate; And
A second excitation light source for emitting a second excitation light to the phosphor substrate;
And a light source unit for emitting light. The method according to claim 1,
The first excitation light source is disposed on one surface of the phosphor substrate and irradiates the first excitation light to the phosphor substrate,
Wherein the second excitation light source is located on the other surface of the phosphor substrate and irradiates the second excitation light to the phosphor substrate. 3. The method of claim 2,
The first excitation light source is a blue light emitting diode,
And the second excitation light source is a blue laser diode. 4. The method according to any one of claims 1 to 3,
A red dichroic mirror disposed on the optical path of the second excitation light source;
, ≪ / RTI >
Wherein the red dichromatic mirror reflects red light emitted by the phosphor layer to the outside of the light source device. The method according to claim 1,
A light synthesizing module for synthesizing the first excitation light and the second excitation light and irradiating the synthesized light to the phosphor substrate;
The light source device further comprising: The method according to claim 1,
The light source device includes:
A second light source module for emitting green light; And
A third light source module for emitting blue light;
The light source device further comprising: A light source device according to at least one of claims 1 to 6; And
An image converting device for forming an image using light incident from the light source device;
And an image projection device. 8. The method of claim 7,
Wherein the image conversion apparatus comprises:
A reflection type display panel, a transmissive display panel, and a DLP (Digital Light Processor) display panel.

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