WO2014174559A1

WO2014174559A1 - Light source apparatus and image display apparatus

Info

Publication number: WO2014174559A1
Application number: PCT/JP2013/061713
Authority: WO
Inventors: 啓安達; 雅千福井; 長平小野; 浩平三好
Original assignee: 日立マクセル株式会社
Priority date: 2013-04-22
Filing date: 2013-04-22
Publication date: 2014-10-30

Abstract

Provided is a light source apparatus wherein an increase of the number of constituting components is suppressed, while using a plurality of light sources. This light source apparatus is provided with: a first excitation light source that generates first excitation light; a second excitation light source that generates second excitation light; a fluorescent wheel having a fluorescent material that generates fluorescent light by being excited by means of the first and second excitation light; and an optical system, which guides the first excitation light to a first light emitting point on the fluorescent wheel, and the second excitation light to a second light emitting point on the fluorescent wheel, and which outputs fluorescent light from the first and second light emitting points as lighting light. The fluorescent wheel may be provided with a diffusion section that diffuses the first and second excitation light and generates diffused excitation light. Furthermore, the optical system may output, as the lighting light, the fluorescent light from the first and second light emitting points, and the diffused excitation light.

Description

Light source device and image display device

The present invention relates to a light source device and an image display device.

In the relevant technical field, a light source device has been proposed which converts excitation light emitted from a solid state light source into visible light by a phosphor and emits light efficiently. In Patent Document 1, excitation light (blue laser light) emitted from a light source is irradiated to a disc (phosphor wheel) on which a phosphor is formed, and a plurality of fluorescent lights (red light and green light) are emitted. A configuration for use as illumination light is disclosed.

JP, 2011-13313, A

In the light source device of Patent Document 1, in order to improve the brightness, it is conceivable to use a plurality of light source devices. However, simply using a plurality of light sources causes a problem that the number of component parts increases and the external dimensions of the image display apparatus increase and the cost increases.

Therefore, an object of the present invention is to provide a light source device in which an increase in the number of component parts is suppressed while using a plurality of light sources.

In order to solve the above-mentioned subject, one of the desirable modes of the present invention is as follows. The light source device includes a first excitation light source that generates a first excitation light, a second excitation light source that generates a second excitation light, and first and second excitation light to excite fluorescent light. A phosphor wheel having a phosphor to be generated, a first excitation light to a first emission point on the phosphor wheel, and a second excitation light to a second emission point on the phosphor wheel, An optical system is provided which emits fluorescence light from the first and second light emitting points as illumination light.

According to the present invention, it is possible to provide a light source device in which an increase in the number of component parts is suppressed while using a plurality of light sources.

FIG. 2 is a configuration diagram of a light source device in Embodiment 1. The figure which shows the example of the mirror 4. FIG. FIG. 6 is a view showing an example of the spectral characteristics of a region 41 of a mirror 4; FIG. 2 is a view showing a specific example of a phosphor wheel 1; FIG. 2 is a view showing

light emitting points

2 a and 2 b of a phosphor wheel 1. FIG. 7 is a configuration diagram of a light source device in a second embodiment. FIG. 7 is a configuration diagram of a light source device in a third embodiment. The figure which shows the light source device of FIG. 7 seen from the radiation | emission direction of the illumination light 11 (W). FIG. 16 is a configuration diagram of an optical system of a projection type video display device in a fourth embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Hereinafter, red, green, blue, yellow and white will be denoted as R, G, B, Y and W, respectively.

FIG. 1 is a block diagram of the light source device in the first embodiment. The light source device 100 has an excitation light source 5 (5a and 5b) for emitting excitation light 10 (10a and 10b), mirrors 4 (4a and 4b), and a phosphor wheel 1 as main components. The excitation light source 5 is one in which one or more solid light emitting elements such as a laser light emitting element are arranged, and emits, for example, B color laser light as excitation light.

Excitation light beams

10a and 10b (shown by solid lines) are emitted from

excitation light sources

5a and 5b, respectively, collimated by collimating

lenses

6a and 6b, respectively, and enter

parallel mirrors

4a and 4b, respectively. The excitation light emitted from one excitation light source 5 may be divided into excitation lights 10 (10a and 10b).

FIG. 2 shows a specific example of the mirror 4 (here, two examples). The mirror 4 is composed of two areas. The first region is a dichroic coating region 41 (hatched portion) having a characteristic of reflecting the wavelength region of the excitation light (B) and transmitting the wavelength region (R, Y, G) of the fluorescent light. The second region is a wide wavelength transmission region 42 (white portion) transmitting both wavelength regions of excitation light and fluorescence light. The first region has a smaller area than the second region.

The

excitation lights

10a and 10b are reflected by the dichroic coating regions 41 of the

mirrors

4a and 4b, respectively, condensed on the

condenser lenses

3a and 3b, and enter the phosphor wheel 1, respectively. Here,

excitation light

10a and 10b are incident, and let

light emission point

2a and 2b be points which emit fluorescence light or diffusion excitation light, respectively. Then, substantially all of the fluorescent light emitted from the

light emitting points

2a and 2b and most of the diffused excitation light become

illumination lights

11a and 11b respectively to the lower side of the drawing (FIG. 1).

In the example shown in FIG. 2A, the dichroic coating area 41 is divided into a checkered pattern at the center of the incident surface of the mirror 4, and the other part is a wide wavelength transmission area 42. The number of divisions of the dichroic coating area 41 and the size and arrangement thereof are determined in accordance with the number, shape and position of the incident spots 45 (black) of the excitation light 10 from the excitation light source 5. Therefore, the excitation light 10 is reflected at the incident spot 45 and travels to the phosphor wheel 1 substantially all.

On the other hand, the fluorescent light or the diffused excitation light generated at the

light emitting points

2 a and 2 b on the phosphor wheel 1 is expanded and incident on the spot 46 (broken line) on the incident surface of the mirror 4. Among them, substantially all of the fluorescent light in the spot 46 passes through to become illumination light. On the other hand, among the diffused excitation light, the light incident on the dichroic coating region 41 can not be transmitted and becomes loss of illumination light, but most of the diffused excitation light incident on the large wavelength wide wavelength transmission region 42 is transmitted. It becomes illumination light.

The example of FIG. 2 (b) shows a form different from that of FIG. 2 (a). The difference from FIG. 2A is that a dichroic coating region 41 is provided in a rectangular (or square) shape at the center of the incident surface of the mirror 4. In this case, since the incident spot 45 is small, all the spots 45 can be accommodated in one dichroic coated area 41. As compared with FIG. 2A, since the area of the dichroic coating region 41 can be further reduced, the loss of the illumination light by the dichroic coating region 41 is further reduced.

As described above, the mirror 4 of the present embodiment selectively reflects the excitation light 10 from the excitation light source 5 by providing the dichroic coating region 41 in the wide wavelength transmission region 42, and the phosphor 4 on the phosphor wheel 1. While being led to the

light emitting points

2a and 2b, the diffused excitation light from the

light emitting points

2a and 2b can be transmitted to form

illumination lights

11a and 11b.

FIG. 3 is a diagram showing an example of the spectral characteristics of the dichroic coating region 41 of the mirror 4. The horizontal axis represents the wavelength, and the vertical axis represents the transmittance. The dichroic coating region 41 does not transmit the wavelength band of B (about 420 to 470 nm), but transmits wavelength bands (R, Y, G) larger than that. Such spectral characteristics can be realized by using dielectric multilayer films (TiO ₂ , SiO _2, etc.).

FIG. 4 is a view showing a specific example of the phosphor wheel 1. The rotatable phosphor wheel 1 has a phosphor 2 that is excited by the excitation light to emit fluorescence light of a predetermined color. The disc surface of the phosphor wheel 1 is divided into a plurality of regions in the circumferential direction, for example, eight segments, and each segment includes the R phosphor 21, the Y phosphor 22 and the G phosphor 23 as the phosphor 2. It is applied. Further, the remaining segments are provided with a diffuse reflector 24 which diffuses and reflects the excitation light and which has a diffusing function on a reflection mirror. The fluorescent substance 2 generates fluorescent light of three colors of R, Y and G from the

light emitting points

2a and 2b respectively when receiving the

excitation light

10a and 10b, and the diffused reflection light diffused from the diffuse reflection part 24 is generated. In both cases, the light is made approximately parallel light by the condenser lens 3 and is incident on the mirror 4.

Each of the

phosphors

21, 22, 23 receives the excitation light 10 and emits R, Y, G fluorescence light, respectively. The diffusion function of the diffuse reflection section 34 is to mirror-reflect the base material of the phosphor wheel 1 by silver deposition or the like, attach a highly heat-resistant transmission diffusion plate on this, or diffuse it to the reflection surface (paste etc.) It can be realized by applying In this case, the diffusion plate (diffusion material) is an optical path through which the excitation light travels twice, so it is preferable to determine the degree of diffusion in consideration of this. Alternatively, the surface of the reflecting surface itself may be provided with a fine asperity to have a function of diffusing simultaneously with reflection. By diffusing the excitation light reflected by the diffuse reflection unit 24 in this manner, there is an effect of removing speckle noise in the laser light. Further, as the phosphor wheel 1 rotates, the effect of removing speckle noise is further enhanced. Although the excitation light 10 is diffused on the phosphor wheel 1 in order to remove speckle noise in this embodiment, the phosphor plate 1 is not a diffuse reflection part, but has a specular reflection part that performs regular reflection. You may.

FIG. 5 is a view showing the

light emitting points

2 a and 2 b on the phosphor wheel 1. The excitation lights 10 a and 10 b are respectively incident on the regions of the phosphor 2 (21, 22, 23) and the diffuse reflection part 24 of the phosphor wheel 1. Since the

illumination lights

11a and 11b emitted from the

light emission points

2a and 2b need to be the same color, a configuration in which the

light emission points

2a and 2b are on the same color segments (21, 22, 23, 24) That is, the

light emitting points

2a and 2b are arranged in a positional relationship of 180 degrees with respect to the rotation axis. FIG. 5 shows that the

light emitting points

2a and 2b are both on the G color phosphor 23.

The configuration is not limited to the above as long as the

illumination lights

11a and 11b have the same color. For example, the

light emitting points

2a and 2b are disposed at an arbitrary angle α with respect to the rotation axis, and the phosphor wheel 1 is configured to be a segment of the same color at every arbitrary angle α. Also, for example, when two or more excitation light sources 5 are provided and two or more (X) light emitting points are present at equal intervals, the X same colors may be provided such that the same segment comes every 360 / X degrees. Is configured so that there are segments of

Further, the segments of the phosphor wheel 1 may be configured such that the colors of the

illumination lights

11a and 11b differ depending on the conditions of the image display device used, or the positional relationship between the

light emitting points

2a and 2b may be arranged.

The temperature of the phosphor 2 is increased by the increase of the incident excitation light 10, and melting or burning may occur. The rotation of the phosphor wheel 1 lowers the temperature before the excitation light 10 is again incident on the same position of the phosphor 2, and the possibility of melting or burning of the phosphor 2 decreases. If the

light emitting points

2a and 2b are on the same circumference, the

excitation lights

10a and 10b will be incident on the same circumference, preventing the temperature from being lowered, and the possibility of melting or burning increases. As shown in FIG. 5, the temperature of the phosphor 2 is reduced by arranging so that the locus of the light emitting point 2a (dotted line) and the locus of the light emitting point 2b (dotted chain line) do not overlap on the phosphor wheel 1. The possibility of melting or burning can be reduced.

The combination of the color of the excitation light and the color of the phosphor, the number of segments, and the shape (angle) of the segments are not limited to the above example, and may be appropriately changed and used according to the required specification of the illumination light. Just do it. For example, while generating B-color laser light from an excitation light source, removing Y-color phosphor from a phosphor wheel to generate R and G fluorescence light, or other colors such as cyan and magenta as a phosphor It is also possible to add. For example, while generating laser light in the ultraviolet region from the excitation light source, it is also possible to remove the diffuse reflection part from the phosphor wheel and add the phosphor of B to generate B light.

Further, the number of light emitting points and the positional relationship are not limited to the above example, and may be appropriately changed and used according to the required optical specifications and external dimensions of the image display apparatus. For example, it is also possible to increase the number of light emitting points from two to four in the above example in order to increase the brightness of the image display device.

In the second embodiment, the case where the illumination light is emitted to the opposite side of the excitation light source with the phosphor wheel in between will be described. FIG. 6 is a block diagram of the light source device in the second embodiment. The basic configuration of the light source device 100 ′ is the same as that of the first embodiment (FIG. 1), except that each segment of the phosphor wheel 1 ′ is made of a material that transmits light and does not require the mirror 4 .

The phosphor wheel 1 'may be produced by any method such as attaching the phosphor 2' to the surface of a transparent device such as glass, or using a glass containing a phosphor. Furthermore, on the phosphor wheel 1 ′, a diffusion / transmission part that diffuses and transmits the

excitation light

10 a and 10 b is provided.

In the second embodiment, the fluorescent light of R, Y, and G and the diffused excitation light are emitted to the opposite side of the excitation light source 5 across the phosphor wheel 1 and these are disposed over the phosphor wheel 1 ′. The light enters a collimating lens 32 disposed on the opposite side of 5 and becomes substantially parallel light, and becomes illumination light 11.

In the third embodiment, an optical system provided with a bypass optical path for excitation light (B-color light) will be described. FIG. 7 is a block diagram of the light source device in the third embodiment. FIG. 7A is a top view of the light source device 100 '' with respect to the light emitting point 2a, and FIG. 7B is a top view of the light source device 100 '' with respect to the light emitting point 2b. Here, FIG. 7 (a) will be described (FIG. 7 (b) is also the same as FIG. 7 (a)).

The light source device 100 ′ ′ of FIG. 7A has a bypass optical path for excitation light, and has an optical system that combines the illumination light from the bypass optical path with the illumination light reflected from the phosphor wheel 1 ′ ′. The excitation light 10a (shown by a solid line) is emitted from the excitation light source 5a, becomes approximately parallel light by the collimator lens 6a, and enters the mirror 4a ''. The mirror 4 a ′ ′ is a dichroic coated mirror having a characteristic of reflecting the wavelength range of the excitation light (B) and transmitting the wavelength range (R, Y, G) of the fluorescent light.

The excitation light 10a is reflected by the mirror 4a '', condensed by the condenser lens 31a '', and incident on the phosphor wheel 1 ''. The phosphor wheel 1 ′ ′ has a segment of a phosphor that is excited by excitation light to reflect and emit fluorescent light of a predetermined color, and a diffuse transmission part that diffuses and transmits the excitation light. When the excitation light 10a is received, fluorescent light of three colors of R, Y and G is generated from the segment of the phosphor, and the collimating lens 31a ′ ′ becomes illumination light 11a (R, Y, G) of substantially parallel light. The light is incident on the mirror 4a ''.

On the other hand, the diffused excitation light transmitted through the diffusion transmitting portion is incident on the collimating lens 32a ′ ′ and becomes substantially parallel illumination light 11a (B), and mirrors 47a, 48a, 49a that reflect the wavelength range of the excitation light (B) , And enter the mirror 4a ''. The illumination light 11a (B) is reflected by the mirror 4a ′ ′, and is combined with the illumination light 11a (R, Y, G) transmitted through the mirror 4a ′ ′ to become a W color illumination light 11a (W), as shown in FIG. The lower part of A) is irradiated.

FIG. 8 is a view of the light source device of FIG. 7 as viewed from the emission direction of the illumination light 11 (W). In FIG. 8, the upper part of the phosphor wheel 1 ′ ′ is shown in FIG. 7A, and the lower part is arranged with FIG. 7B, so that each phosphor system 1 ′ does not interfere with one phosphor wheel 1 ′. 'Can have two light emitting

points

2a and 2b.

The directions in which the fluorescent light (R, Y, G) and the excitation light (B) are emitted from the phosphor wheel 1 ′ ′ are not limited to those in this embodiment, and each direction may be any direction according to the situation. It goes without saying that it may be emitted to

In the fourth embodiment, an example in which the light source device is applied to a projection type video display device will be described. FIG. 9 is a block diagram of an optical system of a projection type image display apparatus in a fourth embodiment. Among them, the portion of the light source device 100 has the same configuration as that of the first embodiment (FIG. 1). The illumination light (diffuse excitation light) 11 transmitted through the mirror 4 of the light source device 100 is condensed on the condensing lens 71 and is incident on the multiple reflection element 72.

The illumination light 11 that has entered the multiple reflection element 72 is reflected a plurality of times in the multiple reflection element 72, and becomes light having a uniform illuminance distribution. The illumination light emitted from the emission aperture plane of the multiple reflection element 72 is transmitted through the condenser lens 73, reflected by the reflection mirror 74, and then irradiated onto the image display element 75 with a uniform illuminance distribution.

The image display element 75 is, for example, a DMD (Digital Mirror Device). In this case, R light, G light, and B light are time-divisionally irradiated. The excitation light source 5 is a solid light emitting element having a high response speed, and time-division control is possible, so that each color light is time-divisionally modulated by the image display element 75 for each color light. Each color light reflected by the image display element 75 becomes image light, enters the projection lens 76, and is projected on a screen (not shown).

The image display element 75 may use a transmissive or reflective liquid crystal panel. Further, in FIG. 9, the light source device of FIG. 6 or 7 may be used instead of the light source device 100. In addition, the image display apparatus may be configured to have an optical system that combines the illumination light from the light source device of the present invention and the illumination light from another solid light emitting element such as an LED.

The light source device of the present embodiment is compact and can realize high luminance, and contributes to the miniaturization and high performance of the projection type image display device.

1: phosphor wheel 2: 2: phosphor 2a / 2b: emission point on phosphor 3: 3: condenser lens 4: 4: mirror 5: excitation light source 6: 6: collimate lens 10: excitation light 11: illumination Light (fluorescent light and diffuse excitation light), 41: dichroic coated area (first area), 42: wide wavelength transmission area (second area), 100: light source device.

Claims

A first excitation light source generating a first excitation light;
A second excitation light source generating a second excitation light;
A phosphor wheel having a phosphor which is excited by the first and second excitation lights to generate fluorescence light;
The first excitation light is directed to a first light emitting point on the phosphor wheel, the second excitation light is directed to a second light emitting point on the phosphor wheel, and the first and second light emissions are provided. A light source device comprising an optical system that emits fluorescence light from a point as illumination light.
The light source device according to claim 1, wherein the phosphor wheel further includes a diffusion unit that diffuses the first and second excitation lights to generate diffused excitation light.
The light source device according to claim 2, wherein the optical system emits fluorescence light and diffused excitation light from the first and second light emitting points as illumination light.
The light source device according to any one of claims 1 to 3, wherein the illumination light is emitted to the same side as the first and second excitation light sources with the phosphor wheel interposed therebetween.
The light source device according to any one of claims 1 to 3, wherein the illumination light is emitted to the opposite side of the first and second excitation light sources with the phosphor wheel interposed therebetween.
The optical path according to any one of claims 1 to 3, further comprising a bypass optical path for excitation light from the opposite side of the first and second excitation light sources with the phosphor wheel interposed therebetween to the first and second excitation light sources. The light source device as described in.
The light source device according to claim 6, wherein the fluorescent light from the first and second light emitting points and the diffused excitation light having passed through the bypass light path are emitted as illumination light.
The light source device according to any one of claims 1 to 7, wherein the first and second light emitting points are configured not to be located on the same circumference on the phosphor wheel.
The light source device according to any one of claims 1 to 8, wherein the first and second light emitting points are arranged to emit illumination light of the same color.
The light source device according to any one of claims 1 to 9.
Illumination means for combining the plurality of illumination lights;
An image display element that modulates each color light according to an input signal;
And a projection unit configured to project light modulated by the image display element.