JP2011118187A - Light deflection element, light source apparatus and display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light deflection element the light utilization efficiency of which is increased satisfactorily even if a light-emitting area thereof is made smaller and the parallelism of light emitted therefrom is enhanced, and to provide a light source apparatus and a display apparatus. <P>SOLUTION: The light deflection element includes: a dichroic mirror 13 one side of which is arranged so as to face a light source for emitting light having a first wavelength through which the light having the first wavelength is transmitted and on which light having a second wavelength is reflected; an angle selective mirror 16 which is arranged at the other side of the dichroic mirror 13 through which light beams of the light having the second wavelength with enter a predetermined incident angle range are transmitted and on which light beams outside the prescribed incident angle range are reflected; and a wavelength conversion element (phosphor layer 14) which is arranged between the dichroic mirror 13 and the angle-selective mirror 16 and irradiated with the light having the first wavelength to emit the light having the second wavelength. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light deflection element that outputs a condensed light beam, a light source device, and a display device.

  A light source device using a light emitting diode (LED) is used as a light source for illumination of a projector or a liquid crystal display.

  A light source device used for a projector illuminates a display area of a display element by condensing light emitted from an LED with a lens in order to improve projection illuminance and use efficiency of light. In order to further improve the projection illuminance of the projector, a method of increasing the light source luminous flux by arranging a plurality of LEDs side by side is conceivable. However, an LED generally has a Lambert distribution light distribution characteristic and is a surface light source that emits light from the entire light emitting surface, and there is a condensing limit for condensing such a surface light source with a lens or a reflecting mirror. Exists. The illumination area that can be condensed is limited by the product of the spread angle of the LED emission light and the LED light emitting surface area, and it is difficult to collect all the light emitted from the LEDs arranged in a row and reach the display area of the display element. As a result, the light use efficiency decreases.

In recent years, LEDs have been used in light source devices for ultra-compact projectors, taking advantage of the characteristics of LEDs, which are small light sources. The display element of the ultra-small projector is small, and it is difficult to reach all the light emitted from the LED to a small display area due to the light collection limit.
In order to efficiently illuminate a desired area from a surface light source such as an LED, an LED having a high parallelism of emitted light and a small light emitting surface area is required so as not to be limited by the light collection limit.

  Moreover, as a light source device used for a liquid crystal display, a backlight using a light guide plate is used. In such a backlight, a reflection sheet is provided on one surface of the light guide plate, and a diffusion sheet and a prism sheet are provided on the other surface of the light guide plate in order from the side closer to the light guide plate. In this backlight, the illumination light incident from the side surface of the light guide plate exits the light guide plate from the surface on the side where the diffusion sheet is provided. Illumination light is emitted from the light guide plate in an oblique direction close to the horizontal, diffused by the diffusion sheet, and illumination light having an incident angle suitable for the prism sheet characteristics is deflected directly upward by the prism sheet and emitted from the backlight emission surface. Of the illumination light diffused by the diffusion sheet, a part of the illumination light having an incident angle not suitable for the prism sheet characteristics is totally reflected in the prism sheet and returned downward. The illumination light returned downward is transmitted by the diffusion sheet and the light guide plate, and then reflected by the reflection sheet. Thereafter, the reflected illumination light is incident again on the prism sheet via the light guide plate and the diffusion sheet. Here, since the illumination light is diffused by the diffusion sheet, the traveling direction of the returned illumination light is changed. Therefore, a part of the illumination light re-entering the prism sheet becomes an incident angle suitable for the prism sheet characteristics, is deflected in the upward direction by the prism sheet, and is emitted from the backlight emission surface. A part of the other illumination light is totally reflected in the prism sheet and returned again downward.

  As described above, the illumination light is repeatedly reflected between the prism sheet and the reflection sheet, so that the illumination light in a specific incident direction is emitted directly upward from the prism sheet. However, in this backlight, since the light guide plate and the diffusion sheet are provided between the prism sheet and the reflection sheet, the loss of the illumination light when the illumination light passes between the prism sheet and the reflection sheet increases.

Further, part of the illumination light having an incident angle that is not suitable for the prism sheet characteristic is a light beam having an angle that is not totally reflected in the prism sheet, and is transmitted through the prism sheet. These rays are deflected and emitted in a direction that is not directly above the backlight emission surface. In other words, in order to increase the brightness of the liquid crystal display, it is desirable that there is a lot of emission in the upward direction, but the light collection method by the prism sheet has a large amount of emitted light in a direction other than the desired direction, and the light distribution distribution is widened. High brightness is difficult.
The parallelism of the emitted light of such a backlight is lower than the parallelism of the emitted light when the LED is collected by the lens, and the light use efficiency is lower than the use efficiency of the light source device in the projector.

  In view of this, an optical deflection element having a high degree of parallelism of emitted light and a light source device having the same and having a small light emitting area have been proposed (see, for example, Patent Document 1).

  The light source device disclosed in Patent Document 1 includes a light source provided on a substrate and a light deflection element that controls the deflection direction of light emitted from the light source. The light source includes a silver layer corresponding to a reflective material layer, a p-type semiconductor layer, a light generation region, and an n-type semiconductor layer on a substrate. The silver layer reflects at least 50% of the light generated by the light generation region and impinges on the silver layer. The light deflection element is composed of a pattern layer composed of a plurality of openings, has a dielectric function that varies spatially according to the pattern, enhances the light extraction efficiency near the exit surface normal, and emits light emitted from the light deflection element However, the light emission is controlled so that the parallelism is higher than the Lambertian distribution.

JP-T-2006-523957 (FIGS. 1-2)

  However, the light deflection element and the light source device disclosed in Patent Document 1 have a problem that there is a lot of light that is not effectively used among the light emitted from the light generation region described above.

  In this conventional light deflection element, even when combined with a light source, the light emitted from the light generation region in the direction near the normal of the emission surface with a relatively small emission area passes through the pattern layer composed of a plurality of openings. However, the light emitted from the light generation region at a wide angle is reflected by the pattern layer, which is a light deflection element, and returned to the light generation region without being emitted from the element emission surface. A part of the light returned in the direction of the light generation region becomes light that is confined in the light generation region having a high refractive index and becomes stray light, or light that is absorbed inside the n-type or p-type semiconductor layer. It does not exit from the device.

  In addition, a part of light having an angle that cannot be emitted from the opening of the pattern layer (light reflected by the pattern layer) is guided to the silver layer on the back surface. The light that reaches the silver layer is reflected and travels toward the exit surface again, but is absorbed by the light generation region, the n-type or p-type semiconductor layer, or the power supply electrode formed on the surface of the element. Attenuated by blocked light. Here, a part of the light reflected by the silver layer is again directed to the pattern layer and can be emitted if the light beam angle can be emitted from the opening of the pattern layer, but there is no element that greatly changes the light beam angle inside the light source device. Less light can be emitted from the device.

  As described above, in the light deflecting element and the light source device of Patent Document 1, light that cannot be emitted from the light deflecting element is attenuated while reciprocating inside the light source, or the light beam angle can be efficiently changed in the target direction. For this reason, there is a problem that the light emitted from the light generation region cannot be effectively used.

Therefore, the present invention provides a light deflection element with sufficiently high utilization efficiency of light even when the parallelism of the emitted light is increased, and a light source device in which the light emission area is reduced by combining this light deflection element and a light source, Another object of the present invention is to provide a display device incorporating the light deflection element and the light source device.

  According to one aspect of the present invention, an optical deflection element is provided. The light deflection element is disposed so that one side thereof faces a light source that emits light having a first wavelength, transmits a light having a first wavelength, and reflects a light having a second wavelength. An angle selective mirror that is disposed on the other side of the dichroic mirror, transmits a light beam within a predetermined incident angle range of light of the second wavelength, and reflects a light beam outside the predetermined incident angle range; and a dichroic mirror; A wavelength conversion element that is disposed between the angle selective mirrors and emits light of the second wavelength when irradiated with light of the first wavelength.

  The light deflection element preferably further includes an angle conversion layer that changes the traveling direction of light disposed between the dichroic mirror and the angle selective mirror.

  Alternatively, in the above optical deflection element, the wavelength conversion element preferably includes a scatterer that scatters light.

  Further, each of the above-described optical deflecting elements preferably further includes a dichroic mirror that reflects the light of the first wavelength and transmits the light of the second wavelength between the wavelength conversion element and the angle selective mirror.

  According to one aspect of the present invention, a light source device is provided. The light source device includes: a light source that emits light of a first wavelength; and an angle selective mirror that transmits light rays within a predetermined incident angle range and reflects light rays outside the predetermined incident angle range. Only light rays within a predetermined incident angle range of the light of the second wavelength generated by using the light of the first wavelength are emitted. In this light source device, any one of the light deflection elements described above is arranged in the order of the light source, the dichroic mirror, the wavelength conversion element, and the angle selective mirror.

  According to still another aspect of the present invention, a display device is provided. Such a display device includes any one of the light source devices described above and a spatial light modulation device that modulates the intensity of light emitted from the light source device according to an image to be displayed.

  According to still another aspect of the present invention, a display device is provided. Such a display device includes any one of the above-described light deflection elements and a spatial light modulation device that modulates the intensity of light emitted from the light deflection elements in accordance with an image to be displayed.

  The light deflection element according to the present invention can sufficiently increase the light use efficiency even if the parallelism of the emitted light is increased. Further, when this light deflection element is combined with a light source, a light source device and a display device having a small light emitting area can be realized.

1 is a schematic configuration diagram of a light deflection element and a light source device according to a first embodiment of the present invention. It is a figure explaining operation | movement of the optical deflection | deviation element and light source device which concern on the 1st Embodiment of this invention. It is a schematic block diagram of the optical deflection element and light source device which concern on the 2nd Embodiment of this invention. It is a figure explaining operation | movement of the optical deflection | deviation element and light source device which concern on the 2nd Embodiment of this invention. It is a schematic block diagram of an example of a light deflection element and a light source device having a second dichroic mirror that reflects excitation light and transmits fluorescence. It is a schematic block diagram of a liquid crystal projector using either the light deflection element or the light source device according to each embodiment. It is a schematic block diagram of the backlight for liquid crystal displays using any of the light deflection elements by each embodiment.

Hereinafter, an optical deflection element and a light source device including the same according to one embodiment will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a light deflection element and a light source device according to the first embodiment. As shown in FIG. 1, the light source device 1 includes a light source 11 formed on a substrate 10 and a light deflecting element 12 disposed on the light source 11.

  The light source 11 is a light source that emits light rays with a wide light distribution characteristic such as a Lambertian distribution and emits excitation light having a predetermined wavelength. The predetermined wavelength can be a wavelength at which the fluorescent substance included in the light deflection element 12 can emit fluorescence, for example, a wavelength corresponding to near ultraviolet to blue. For example, the light source 11 can be a light emitting diode (LED) that emits light having a wavelength of 405 nm. The light source 11 is not limited to the above-described LED, and may be, for example, a fluorescent tube, a cold cathode tube, a high-pressure mercury lamp, or an organic electro-luminescence (Organic Electro-Luminescence, organic EL) element, and does not necessarily require light deflection. It does not have to be formed integrally with the element 12.

  The light deflection element 12 emits fluorescence by the excitation light emitted from the light source 11, collects and outputs the fluorescence. Therefore, the light deflection element 12 includes, in order from the light source 11 side, a dichroic mirror 13, a phosphor layer 14 that is an example of a wavelength conversion element, and a microlens array that is an example of an angle conversion layer that changes the traveling direction of light. 15 and an angle selective mirror 16 are stacked. It should be noted that the layers of the light deflection element 12 may be arranged so as to be in close contact with each other, or may be arranged at intervals. Moreover, the arrangement of the phosphor layer 14 and the microlens array 15 may be interchanged.

  In this light deflection element 12, the surface facing the light source 11 of the dichroic mirror 13 is the light incident surface 12a, and the outer surface of the angle selective mirror 16, that is, the surface opposite to the incident surface 12a is the light exit surface. 12b.

  The dichroic mirror 13 transmits light having a wavelength corresponding to excitation light emitted from the light source 11, and reflects light having a wavelength corresponding to fluorescence generated by the phosphor layer 14. Therefore, the dichroic mirror 13 is formed by, for example, a glass layer and a dielectric multilayer film formed on the surface of the glass layer. Alternatively, the dichroic mirror 13 may be formed of a photonic crystal whose dielectric constant changes with a period smaller than the wavelength of the excitation light emitted from the light source 11. For example, the dichroic mirror 13 has a structure in which a plurality of protrusions having a diameter of about 100 nm to 200 nm are formed at a predetermined period on the surface of a transparent member such as glass.

  The phosphor layer 14 functions as a wavelength conversion element and emits fluorescence having a predetermined wavelength by the excitation light emitted from the light source 11. For this purpose, the phosphor layer 14 has a structure in which a phosphor is coated on a glass substrate, for example. Alternatively, the phosphor layer 14 may have a structure in which a phosphor is doped in a glass substrate. Furthermore, the phosphor layer 14 may be a thin film containing a phosphor. In addition, as the wavelength conversion element, a quantum dot or the like that converts the wavelength of light input at a nanoscale may be used instead of the phosphor layer 14 described above.

An appropriate phosphor is selected according to the wavelength of the excitation light emitted from the light source 11 and the wavelength of the light to be output by the light source device 1.
For example, when the light source 11 emits light having a wavelength of 405 nm and the light source device 1 tries to output light having a wavelength corresponding to red, CaAlSiN ₃ : Eu ²⁺ can be used as the red phosphor. When the light source 11 emits light having a wavelength of 405 nm and the light source device 1 tries to output light having a wavelength corresponding to green, as a green phosphor, for example, (Ba, Sr) ₂ SiO ₄ : Eu ^{2 +} Can be used. Further, when the light source 11 emits light having a wavelength of 405 nm and the light source device 1 tries to output light having a wavelength corresponding to blue, as a blue phosphor, for example, Sr ₁₀ (PO ₄ ) ₆ Cl ₂ : Eu ²⁺ can be used.
When the light source 11 emits light having a wavelength of 455 nm and the light source device 1 tries to output light having a wavelength corresponding to yellow, as a yellow phosphor, for example, (Y, Gd) ₃ Al ₅ O ₁₂ : Ce ³⁺ can be used.

  The microlens array 15 functions as an angle conversion layer and changes the traveling direction of incident light. For this purpose, the microlens array 15 has, for example, a structure in which a plurality of minute lenses are arranged in a matrix on the surface of the transparent resin substrate. Alternatively, the glass substrate surface on which the phosphor layer 14 is formed may be a lens surface. Furthermore, the shape of the angle conversion layer is not limited to the lens shape, and may be a diffusing surface, an arbitrary curved surface, or a continuous minute prism.

  The angle selective mirror 16 transmits a light beam within a predetermined incident angle range and reflects a light beam outside the predetermined incident angle range at the emission wavelength emitted by the phosphor. For this purpose, the angle selective mirror 16 is formed of, for example, a glass layer and a dielectric multilayer film formed on the surface of the glass layer. Alternatively, the angle selective mirror 16 may be formed of a selective reflection element such as a photonic crystal in which a photonic band gap is controlled so that a transmission mode does not occur for a light beam outside a predetermined incident angle range. The angle-selective mirror 16 formed in this way transmits, for example, incident light within a range of 10 degrees with respect to the incident surface normal, while incident outside the range of 10 degrees with respect to the incident surface normal. Light rays are reflected.

Hereinafter, the operations and functions of the light source device 1 and the light deflection element will be described with reference to FIG.
Excitation light L _e light source 11 is emitted is incident from the incident surface 12a of the light deflector 12 to the dichroic mirror 13. The excitation light L _e reaches transmitted through the dichroic mirror 13 into the phosphor layer 14. Phosphor layer 14, the excitation light L _e is irradiated, emits fluorescence having a longer wavelength than the wavelength of the excitation light L _e. A part of the fluorescence L _f1 emitted from the phosphor layer 14 is collected by the microlens array 15 and enters the angle selective mirror 16.

The angle selective mirror 16 transmits incident light within a range of 10 degrees with respect to the incident surface normal while reflecting incident light outside the range of 10 degrees with respect to the incident surface normal. Has characteristics. Therefore, the angle selective mirror 16 transmits the light beam L _f2 having an incident angle of 10 degrees or less out of the fluorescence L _f1 and emits it from the emission surface 12b. The microlens array 15 collects the fluorescent light L _f1 that is diffused light and increases the light beam L _f2 that passes through the angle selective mirror 16. However, it is difficult to convert all of the fluorescence L _f1 into the light beam L _f2 , and the angle selective mirror 16 reflects the light beam L _f3 having an incident angle greater than 10 degrees.

In this way, the fluorescence L _f3 reflected by the angle selective mirror 16 is transmitted through the lens surface of the microlens array 15, thereby changing the traveling direction of the light toward the dichroic mirror 13.

Wavelength of the fluorescence is longer than the wavelength of the excitation light L _e, fluorescent L _f3 dichroic mirror 13
Reflected by. The fluorescence L _f3 reflected by the dichroic mirror 13 passes through the phosphor layer 14 and the microlens array 15 again and is _collected , and then enters the angle selective mirror 16. As with the first fluorescence L _f1 , the fluorescence L _f3 that re-enters the angle selective mirror 16 transmits light with an incident angle within 10 degrees and exits from the exit surface 12 b, and reflects light with an incident angle greater than 10 degrees again. To do.

Further, the remaining part of the fluorescence emitted from the phosphor layer 14 does not go to the angle selective mirror 16 but goes to the dichroic mirror 13. This part of the fluorescence is also reflected by the dichroic mirror 13, then passes through the phosphor layer 14 and the microlens array 15 and travels toward the angle selective mirror 16. For this reason, the remaining part of the fluorescence is also transmitted through the incident angle within 10 degrees and emitted from the emission surface 12b in the same manner as the part L _{f1 of} the fluorescence directed directly from the phosphor layer 14 to the angle selective mirror 16. To do.

  In the above description, the configuration example in which the microlens array 15 corresponding to the angle conversion layer is disposed between the phosphor layer 14 and the angle selective mirror 16 is shown. However, the microlens array 15 is not provided, and Even if the parallelism of the emitted light is increased, the light deflection element has a sufficiently high light utilization efficiency. The operation in that case will be described below.

As described above, the microlens array 15 having the above-described configuration is for condensing the fluorescent light L _f1 that is the diffused light and increasing the light beam L _f2 that is transmitted through the angle selective mirror 16. 12, much light passes through the angle selective mirror 16 immediately after the fluorescent light is emitted from the phosphor layer 14. Here, when the microlens array 15 is not disposed in the light deflection element, the light reflected by the angle selective mirror 16 can be increased, but the reflected light is a fluorescence between the dichroic mirror 13 and the angle selective mirror 16. It is confined in the body layer 14 and is repeatedly reflected. Since the phosphor layer 14 has a configuration in which, for example, a phosphor is doped in a glass substrate, the reflected light gradually changes its light beam angle by transmitting or reflecting the phosphor, and after a predetermined light beam angle is reached. It passes through the angle selective mirror 16. In this way, the phosphor layer 14 also functions as an angle conversion layer, but the microlens array 15 is arranged as described above in accordance with the light emission distribution characteristics and transmission and reflection characteristics of the wavelength conversion element such as the phosphor. The structure to add and the structure which added the scatterer to the fluorescent substance layer so that it may mention later can be suitably selected as needed.

As has been described, the light deflector 12 according to the first embodiment, the excitation light L _e from the light source 11, and outputs the fluorescence L _f1 generated by the phosphor layer 14. In this optical deflecting element 12, the emitted light is controlled so that only light within a range of 10 degrees with respect to the normal of the exit surface is emitted. The light can be output.

The light source apparatus 1 having the light deflector 12, to obtain the above-described functions, the area of the exit surface 12b, can be the same size as the light source 11 emits excitation light L _e, the light emitting area Makes it possible to realize a small device.

According to the light deflection element 12, the fluorescence L _f1 emitted from the phosphor layer 14 is confined in a thin space between the angle selective mirror 16 and the dichroic mirror 13. Only the phosphor layer 14 and the microlens array 15 are used, and there are members that block light, such as materials and electrodes that have a high refractive index and cause stray light and absorption, as in conventional light source devices. do not do. Accordingly, light attenuation due to repeated reflection in the light deflecting element 12 can be suppressed as much as possible, loss of fluorescence is suppressed, and the light deflecting element 12 having the highest possible light utilization efficiency and the light source device 1 including the same. It can be.

Next, a light source device according to a second embodiment will be described.
FIG. 3 is a schematic configuration diagram of the light deflection element and the light source device according to the second embodiment. As illustrated in FIG. 3, the light source device 2 includes a light source 11 formed on the substrate 10 and a light deflection element 22 disposed on the light source 11. The light deflection element 22 has a structure in which a dichroic mirror 13, a fluorescent scatterer layer 24, and an angle selective mirror 16 are stacked in order from the light source 11 side. In FIG. 3, the same reference numerals as those of the corresponding components of the light source device 1 shown in FIG.

  The light deflecting element 22 according to the second embodiment is different from the light deflecting element 12 according to the first embodiment in that the light deflecting element 22 does not have a microlens array, and a scatterer is present in the phosphor layer. The difference is that the fluorescent scatterer layer 24 is added. Therefore, in the following description, differences from the optical deflection element 12 according to the first embodiment will be described.

  The fluorescent scatterer layer 24 that is a wavelength conversion element includes a scatterer in addition to the fluorescent material. As this scatterer, for example, fine particles such as glass having a refractive index different from the refractive index of the glass substrate of the fluorescent scatterer layer 24 can be used. The fluorescent scatterer layer 24 also functions as an angle conversion layer by changing the traveling direction of light by scattering incident light. Instead of the fluorescent scatterer layer 24, an element in which a layer in which quantum dots are formed and a transparent member such as glass containing the scatterer may be used as the wavelength conversion element, or the fluorescent scatterer. The layer 24 may have a form in which no scatterer is mixed.

Next, operations and functions of the light deflection element 22 and the light source device 2 will be described with reference to FIG.
Excitation light L _e light source 11 is emitted is incident from the incident surface 22a of the light deflector 22 facing the light source 11 to the dichroic mirror 13. The excitation light L _e reaches transmitted through the dichroic mirror 13 to the fluorescent scattering layer 24. Fluorescent scattering layer 24, the excitation light L _e is irradiated, emits fluorescence having a longer wavelength than the wavelength of the excitation light L _e. A part of the fluorescence L _f1 emitted from the fluorescent scatterer layer 24 enters the angle selective mirror 16.

As in the first embodiment, the angle-selective mirror 16 transmits incident light within a range of 10 degrees with respect to the incident surface normal, while out of the range of 10 degrees with respect to the incident surface normal. Incident light has selective reflection characteristics to reflect. Therefore, the light beam L _f2 having an incident angle of 10 degrees or less of the fluorescence L _f1 is transmitted and emitted from the emission surface 22b. On the other hand, the angle selective mirror 16 reflects the light beam L _f3 having an incident angle greater than 10 degrees.

The fluorescence L _f3 reflected by the angle selective mirror 16 is scattered by the fluorescent scatterer layer 24, thereby changing the traveling direction of the light and going toward the dichroic mirror 13. The fluorescence L _f3 reflected by the dichroic mirror 13 is again scattered by the fluorescence scatterer layer 24 and then enters the angle selective mirror 16. As with the first fluorescence L _f1 , the fluorescence L _f3 re-entering the angle selective mirror 16 transmits light rays with an incident angle of 10 degrees or less and exits from the emission surface 22b, and reflects light rays with an incident angle larger than 10 degrees again. To do.

The remaining part of the fluorescence L _f1 emitted from the fluorescent scatterer layer 24 does not go to the angle selective mirror 16 but goes to the dichroic mirror 13. This part of the fluorescence L _f1 is also reflected by the dichroic mirror 13 and then passes through the fluorescence scatterer layer 24 toward the angle selective mirror 16. For this reason, the remaining part of the fluorescence L _f1 also transmits and emits a light beam with an incident angle of 10 degrees or less, like the part L _f1 of the fluorescence L _f1 directly directed from the fluorescent scatterer layer 24 to the angle selective mirror 16. The light exits from the surface 22b.

As described above, the fluorescence L _f3 is reflected by the dichroic mirror 13 and the angle selective mirror 16, and repeatedly transmits only the fluorescent scatterer layer 24 disposed therebetween. And fluorescence L _f3
Each time the light enters the angle selective mirror 16, a light beam having an incident angle within 10 degrees is transmitted through the angle selective mirror 16. Therefore, the fluorescence L _f1 and L _f3 emitted from the fluorescent scatterer layer 24 are emitted from the light deflection element 22 as condensed light beams with an emission angle of 10 degrees or less.

As described above, in the light deflection element 22 according to the second embodiment, only the fluorescent scatterer layer 24 is disposed between the angle selective mirror 16 and the dichroic mirror 13. Therefore, the fluorescence L _f3 emitted from the fluorescent scatterer layer 24 passes between the angle selective mirror 16 and the dichroic mirror 13, that is, only through the fluorescent scatterer layer 24 until it is emitted from the angle selective mirror 16. In this way, since the loss of fluorescence in the light deflection element 22 is suppressed, the light source device 2 with improved light utilization efficiency of this element can be provided.

  Further, the light source device 2 of the present embodiment can be manufactured at a lower cost as compared with the first embodiment because the microlens array 15 (FIG. 1) is not provided and the thickness of the device is reduced.

Further, the light source device 2 having the light deflector 22, to obtain the above-described functions, the exit area, as large Satoshi a light source 11 that emits excitation light L _e, emission area enabling the implementation of the small device structure And

Next, an optical deflection element and an optical device according to the third embodiment will be described.
In the optical device of the third embodiment, excitation emitted from the light source 11 on either the light emitting side or the light incident side of the angle selective mirror 16 in the optical devices 1 and 2 in the first or second embodiment. reflects light L _e, excitation light emitted from the phosphor layer 14 (FIG. 2) or a fluorescent scattering layer 24 "second dichroic mirror" for transmitting the fluorescence L _f1 emitted (Figure 4), or the light source 11 to absorb the L _e was a structure in which to place the "wavelength filter". In the following description, an example in which the “second dichroic mirror” is arranged will be described. However, the above “wavelength filter” may be arranged instead.

FIG. 5 is a schematic configuration diagram of an example of a light deflection element and a light source device having a second dichroic mirror that reflects excitation light emitted from a light source and transmits fluorescence emitted from a phosphor.
A light source device 3 illustrated in FIG. 5 includes a light source 11 formed on a substrate 10 and a light deflection element 32 disposed on the light source 11. The light deflection element 32 has a structure in which the first dichroic mirror 13, the fluorescent scatterer layer 24, the second dichroic mirror 37, and the angle selective mirror 16 are laminated in order from the light source 11 side. In FIG. 5, the same reference numerals as those of the corresponding components of the light source device shown in FIG.

  The light deflecting element 32 according to the present embodiment emits fluorescence by the excitation light emitted from the light source 11, and collects and outputs the fluorescence. The light deflection element 32 is different from the light deflection element 22 included in the light source device 2 according to the second embodiment in that it includes a second dichroic mirror 37. Therefore, in the following description, differences from the optical deflection element 22 according to the second embodiment will be described.

  In the light deflection element 32 in the present embodiment, the second dichroic mirror 37 reflects light having a wavelength corresponding to the excitation light emitted from the light source 11, while receiving light having a wavelength corresponding to fluorescence generated by the fluorescent scatterer layer 24. To Penetrate. For this purpose, the second dichroic mirror 37 is formed of, for example, a glass layer and a dielectric multilayer film or photonic crystal formed on the surface of the glass layer, like the first dichroic mirror 13.

In the fluorescent scatterer layer 24, if the amount of the phosphor contained in this layer is increased, the excitation light emitted from the light source 11 is so small that the excitation light that is wavelength-converted into fluorescence and reaches the angle selective mirror 16 can be ignored. Become. However, such an amount of the phosphor needs to be noted because it may reduce the light use efficiency of the light source device. This is because if the amount of the phosphor contained in the fluorescent scatterer layer 24 is too large, the fluorescence emitted from the phosphor easily hits other phosphors, and the transmittance of the fluorescent scatterer layer 24 is lowered. The second dichroic mirror 37 transmits the fluorescent scatterer layer 24 and selects the angle when the concentration of the fluorescent substance contained in the fluorescent scatterer layer 24 is optimized so that the light emission efficiency of the light source device 3 is increased. The excitation light reaching the directional mirror 16 is reflected.

  In this way, the light deflection element 32 composed of the first dichroic mirror 13, the fluorescent scatterer layer 24, the second dichroic mirror 37, and the angle selective mirror 16 allows the short wavelength excitation light to be transmitted to other elements. While preventing damage, the fall of the transmittance | permeability of the fluorescent scatterer layer 24 can be suppressed, and the utilization efficiency of light can be improved.

  As a result, the light deflection element 32 is arranged such that light with a short wavelength (for example, near-ultraviolet light) emitted from the light source 11 passes through the angle selective mirror 16 and is disposed at a predetermined interval on the emission surface 12b side. Thus, it is possible to suppress the arrival to another optical member (not shown), and to suppress the damage of the other optical member due to the short wavelength light as much as possible.

  In each of the first to third embodiments, the phosphor layer or the fluorescent scatterer layer may include a substrate such as glass and a phosphor formed as a columnar crystal on the substrate. In this case, the columnar crystal is formed so that the longitudinal direction of the columnar crystal is substantially orthogonal to the reflection surface of the dichroic mirror. By forming the phosphor in this way, a part of the fluorescence propagates while being totally reflected in the columnar crystal. As a result, the amount of fluorescent components incident substantially perpendicular to the reflecting surface of the dichroic mirror increases, so that loss due to the dichroic mirror can be reduced.

Next, a display device according to the fourth embodiment will be described.
FIG. 6 is a diagram showing an example of a display device using any one of the light source devices according to the above-described embodiments according to the fourth embodiment. In FIG. 6, a schematic configuration of a liquid crystal projector is shown. The display device of this embodiment is configured to include any of the light source devices according to the above-described embodiments and a liquid crystal panel that is a spatial light modulator.

  The liquid crystal projector 4 shown in FIG. 6 includes light source devices 41g, 41b, and 41r, dichroic mirrors 42b and 42r, a liquid crystal panel 43, a drive circuit 44, a controller 45, a synchronization circuit 46, and a projection optical system 47. Have.

  The light source devices 41g, 41b, and 41r are each a light source device according to any of the above embodiments. Among these, the light source device 41g is disposed behind the liquid crystal panel 43 with the dichroic mirrors 42b and 42r interposed therebetween. The light source device 41g outputs the condensed emitted light having a wavelength corresponding to green. Therefore, the phosphor layer or the fluorescent scatterer layer of the light deflection element 411g included in the light source device 41g includes a phosphor that emits light having a wavelength corresponding to green.

  The light source device 41 b is arranged so that the light output from the light source device 41 b is reflected by the dichroic mirror 42 b and reaches the liquid crystal panel 43. The light source device 41b outputs the condensed emitted light having a wavelength corresponding to blue. Therefore, the phosphor layer or the fluorescent scatterer layer of the light deflection element 411b included in the light source device 41b includes a phosphor that emits light having a wavelength corresponding to blue.

Further, the light source device 41 r is arranged so that the light output from the light source device 41 r is reflected by the dichroic mirror 42 r and reaches the liquid crystal panel 43. The light source device 41r outputs the condensed emitted light having a wavelength corresponding to red. Therefore, the light source device 41
The phosphor layer 14 (FIG. 1) or the fluorescence scatterer layer 24 (FIG. 3) of the light deflection element 411r included in r includes a phosphor that emits light having a wavelength corresponding to red.

  The dichroic mirror 42b reflects light having a wavelength equal to or shorter than the wavelength corresponding to blue, and transmits light having a wavelength longer than the wavelength corresponding to blue. The dichroic mirror 42r reflects light having a wavelength equal to or greater than the wavelength corresponding to red, and transmits light having a wavelength shorter than the wavelength corresponding to red. Therefore, the light output from the light source device 41 g passes through the dichroic mirrors 42 b and 42 r and reaches the liquid crystal panel 43. On the other hand, the light output from the light source device 41 b is reflected by the dichroic mirror 42 b and reaches the liquid crystal panel 43. The light output from the light source device 41 r is reflected by the dichroic mirror 42 r and reaches the liquid crystal panel 43.

  Although the dichroic mirrors 42b and 42r are illustrated as overlapping, the dichroic mirrors 42b and 42r may be disposed so as not to overlap each other. Further, instead of the dichroic mirrors 42b and 42r, dichroic prisms having the same functions as those two dichroic mirrors 42r and 42b may be used.

  The controller 45 controls the drive circuit 44 and the light source devices 41b, 41g, and 41r based on an image signal input from an external device connected to the liquid crystal projector 4 via an interface circuit (not shown). In the present embodiment, the controller 45 controls the liquid crystal panel 43 and the light source devices 41b, 41g, and 41r by a color sequential driving method. Therefore, the controller 45 generates a single color image signal corresponding to a red image, a blue image, and a green image from the input image signal. Then, the controller 45 outputs each single color image signal to the drive circuit 44.

  The controller 45 adjusts the light emission timing of each light source device based on the synchronization signal supplied from the synchronization circuit 46. Then, the controller 45 turns on the light source device 41 b at a timing when a blue image is displayed on the liquid crystal panel 43. Similarly, the controller 45 turns on the light source device 41g when the green image is displayed on the liquid crystal panel 43, and turns on the light source device 41r when the red image is displayed on the liquid crystal panel 43.

  The drive circuit 44 generates a drive signal for driving the liquid crystal panel 43 based on an image signal input from the controller 45 and corresponding to an image to be displayed. Based on the synchronization signal supplied from the synchronization circuit 46, the drive circuit 44 outputs a drive signal corresponding to each of the red image, the green image, and the blue image, and the timing when the light source devices 41r, 41g, and 41b are turned on. Synchronize with.

  The synchronization circuit 46 generates a synchronization signal for synchronizing the timing at which each light source device outputs red light, blue light, and green light and the timing at which the liquid crystal panel 43 displays a red image, blue image, and green image, The generated synchronization signal is output to the controller 45 and the drive circuit 44, respectively.

  The liquid crystal panel 43 functions as a two-dimensional array spatial light modulator. Then, the liquid crystal panel 43 changes the transmittance for the illumination light emitted from each light source device in units of pixels in accordance with the drive signal supplied from the drive circuit 44, and the light from each light source device that passes through the liquid crystal panel 43. An image is displayed by modulating the light intensity.

  The projection optical system 47 projects the image displayed on the liquid crystal panel 43 onto a screen installed at a predetermined distance from the liquid crystal projector 4.

Next, a configuration example of another display device according to the fourth embodiment will be described.
The light deflection elements included in the light source devices 41r, 41g, and 41b according to each of the above embodiments can be used as a brightness enhancement sheet that increases the amount of light in the upward direction in a backlight for a liquid crystal display.

  FIG. 7 is a diagram showing another example of a display device using any of the light deflection elements according to each embodiment of the present invention. In FIG. 7, a schematic configuration of a liquid crystal display is shown. The display device of this embodiment is configured to include any of the light deflection elements according to the above-described embodiments and a liquid crystal panel which is a spatial light modulation device.

  The liquid crystal display 5 illustrated in FIG. 7 includes a liquid crystal display backlight 50, a liquid crystal panel 54, and a controller 55. The liquid crystal display backlight 50 includes a light source 51, a light guide plate 52, and a brightness enhancement sheet 53 configured by the light deflection element according to any of the above embodiments.

  The light source 51 includes, for example, a fluorescent tube, a cold cathode tube, or an LED, and an excitation having a wavelength capable of causing the fluorescent material included in the fluorescent material layer or the fluorescent scatterer layer included in the brightness enhancement sheet 53 to emit fluorescence. Emits light.

  The light source 51 is disposed close to the side surface of the light guide plate 52. Therefore, the excitation light emitted from the light source 51 propagates through the light guide plate 52 and is emitted from the surface 52 a of the light guide plate 52 toward the brightness enhancement sheet 53. It should be noted that a reflection sheet is disposed on the lower surface side of the light guide plate 52, a diffusion sheet is disposed between the light guide plate 52 and the brightness enhancement sheet 53, and a reflective polarizing element is disposed between the brightness enhancement sheet 53 and the liquid crystal panel 54. Good.

  The excitation light emitted from the light guide plate 52 is incident on the incident surface 53 a of the brightness enhancement sheet 53, whereby fluorescence is emitted in the brightness enhancement sheet 53. In order to generate white light in the brightness enhancement sheet 53, for example, the excitation light of the light source 51 is set to near ultraviolet rays, and the wavelength conversion element included in the brightness enhancement sheet 53 includes red phosphor, green phosphor, and blue phosphor 3 It is preferable that a kind of phosphor is included.

  The fluorescence generated in the brightness enhancement sheet 53 is collected and emitted from the exit surface 53 b of the brightness enhancement sheet 53. The condensed emitted light is incident on the liquid crystal panel 54 disposed in the vicinity of the emission surface 53b of the backlight 50 for the liquid crystal display.

  The liquid crystal panel 54 functions as a two-dimensional array spatial light modulator. The liquid crystal panel 54 changes the transmittance with respect to the irradiation light from the brightness enhancement sheet 53 in units of pixels in accordance with the drive signal supplied from the controller 55, and the light from the brightness enhancement sheet 53 that is transmitted through the liquid crystal panel 54. The image is displayed by modulating the intensity.

  The controller 55 controls the liquid crystal panel 54 based on an image signal input from an external device connected to the liquid crystal display 5 via an interface circuit (not shown). Therefore, the controller 55 generates a drive signal corresponding to the input image signal and outputs the drive signal to the liquid crystal panel 54.

  The brightness enhancement sheet 53 converts the excitation light emitted from the light guide plate 52 in an oblique direction close to the horizontal to white light, deflects the light directly above the emission surface of the backlight 50 for the liquid crystal display, and collects and parallels the light. A high degree of outgoing light is emitted.

  If a reflective polarizing element is disposed between the brightness enhancing sheet 53 and the liquid crystal panel 54 for polarization control, the return light from the reflective polarizing element does not return to the light guide plate 52 but within the brightness enhancing sheet 53. It can be reflected and re-entered on the liquid crystal panel 54. According to this configuration, the return light of polarization control can be transmitted through only a member with a small loss through a short path and re-enter the liquid crystal panel 54. Therefore, the light utilization efficiency can be further increased.

  Thus, according to this embodiment, a liquid crystal panel is disposed in the vicinity of the exit surface of the brightness enhancement sheet, thereby realizing a display device with high light utilization efficiency and high brightness.

  As described above, those skilled in the art can make various modifications in accordance with the embodiment to be implemented within the scope of the present invention.

1, 2, 3 Light source device 4 Liquid crystal projector 5 Liquid crystal display 10 Substrate 11 Light source 12, 22, 32 Light deflection element 13 (First) dichroic mirror 14 Phosphor layer 15 Micro lens array 16 Angle selective mirror 24 Fluorescent scatterer Layer 37 Second dichroic mirror 41b, 41g, 41r Light source device 42b, 42r Dichroic mirror 43 Liquid crystal panel 44 Drive circuit 45 Controller 46 Synchronization circuit 47 Projection optical system 50 Backlight 51 Light source 52 Light guide plate 53 Brightness increasing sheet 54 Liquid crystal panel 55 controller

Claims (7)

A dichroic mirror disposed on one side to face a light source that emits light of a first wavelength, transmits light of the first wavelength, and reflects light of a second wavelength;
An angle selective mirror that is disposed on the other side of the dichroic mirror, transmits a light beam within a predetermined incident angle range of the light of the second wavelength, and reflects a light beam outside the predetermined incident angle range;
A wavelength conversion element that is disposed between the dichroic mirror and the angle selective mirror and emits light of the second wavelength by being irradiated with light of the first wavelength;
An optical deflection element comprising:   The optical deflection element according to claim 1, further comprising an angle conversion layer that is disposed between the dichroic mirror and the angle selective mirror and changes a traveling direction of light.   The light deflection element according to claim 1, wherein the wavelength conversion element includes a scatterer that scatters light.   The wavelength conversion element further includes a dichroic mirror that reflects the light of the first wavelength and transmits the light of the second wavelength between the wavelength conversion element and the angle selective mirror. The optical deflection element according to any one of claims 1 to 3. A light source that emits light of a first wavelength;
An angle selective mirror that transmits light rays within a predetermined incident angle range and reflects light rays outside a predetermined incident angle range;
In the light source device that emits only the light beam within the predetermined incident angle range of the light of the second wavelength generated by using the light of the first wavelength from the light source,
The light deflection element according to any one of claims 1 to 4,
The light source device, wherein the light source, the dichroic mirror, the wavelength conversion element, and the angle selective mirror are arranged in this order. A light source device according to claim 5;
A spatial light modulation device for displaying the image by modulating the intensity of the light emitted from the light source device according to the image to be displayed;
A display device comprising: An optical deflection element according to any one of claims 1 to 4,
A spatial light modulator that displays the image by modulating the intensity of the light emitted from the light deflection element according to the image to be displayed;
A display device comprising:

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