JP2021051129A - Light source device and projector - Google Patents

Abstract

To provide a light source device and a projector that can reduce uneven illuminance.SOLUTION: A light source device comprises: a plurality of laser light sources 121, 123 that emit laser beams 11a, 11c; a light separation element 15 that transmits first light beams 17a, 17c of the laser beams 11a, 11c and reflects second light beams 18a, 18c of the laser beams 11a, 11c; a diffusion element 14 that is provided on the subsequent stage of the light separation element 15 and diffuses the incident light beams; and a reflecting element 16 that reflects the second light beams 18a, 18c reflected by the light separation element 15 toward the diffusion element 14. The first light beams 17a, 17c are converged in a convergence area 141 on the diffusion element 14, and the plurality of laser light sources 121, 123 are arranged substantially orthogonal to the diffusion element 14 and to be rotationally symmetrical to an optical axis ax0 passing through the convergence area 141.SELECTED DRAWING: Figure 5

Description

The present invention relates to a light source device and a projector.

In recent years, with the increase in brightness of projectors, projectors using a laser light source as a light source have begun to spread. Patent Document 1 discloses an image display device in which light emitted from a laser light source is diffused by a diffuser plate and the diffused light is used as a light source.

Japanese Unexamined Patent Publication No. 2008-96777

However, when diffused light is used as a light source, it becomes difficult to make the illuminance of the light uniform due to the limitation of the diffusing ability. Therefore, when diffused light is used as a light source of a display device, uneven illuminance may occur. In particular, when a plurality of laser emitting elements are used as a light source, the tendency is remarkable, and there is a problem that illuminance unevenness due to the arrangement of each laser emitting element is likely to occur.

The light source device of the present application includes a plurality of solid-state light sources that emit first light, a light separation element that transmits the first light beam of the first light and reflects the second light beam of the first light, and the light separation element. A diffusing element provided in the subsequent stage and diffusing the incident light source, and a reflecting element that reflects the second light source reflected by the light separating element toward the diffusing element, and the first light source is provided. , The reflecting element focuses the second light beam on the converging region, and the plurality of solid-state light sources are substantially orthogonal to the diffusing element and pass through the converging region. It is characterized in that it is arranged so as to be rotationally symmetric with respect to the axis.

In the above light source device, the light separation element is reflected by the reflection element and a separation region in which the first light is incident and separates the first light into the first light flux and the second light flux. It is desirable to have a transmission region through which the second luminous flux passes.

In the above light source device, it is desirable that the reflecting element has a negative power.

The light source device includes a fixing member for fixing the plurality of solid light sources, and the fixing member comprises the plurality of fixing members so that the first light flux emitted from the plurality of solid light sources is incident on the convergence region. It is desirable to fix the solid light source.

The projector of the present application is characterized by including the above-mentioned light source device, a light modulation device that modulates the light emitted from the light source device, and a projection lens that projects the light emitted from the light modulation device. ..

The schematic which shows the structure of the light source apparatus. Schematic cross-sectional view of the laser light source viewed from the side. Schematic view of the laser light source as seen from the emission side. The schematic diagram which shows the structure of the 1st fixing member which fixes a 1st laser light source, and 3rd fixing member which fixes a 3rd laser light source. The schematic diagram which shows the structure of the 2nd fixing member which fixes a 2nd laser light source, and the 4th fixing member which fixes a 4th laser light source. The schematic diagram which shows the progress state of the laser light of the light source apparatus in embodiment. The schematic diagram which shows the structure of the light source apparatus at the time of the illuminance distribution simulation in an embodiment. The schematic diagram which shows the structure of the light source apparatus at the time of the illuminance distribution simulation in the comparative example. Simulation result of two-dimensional illuminance distribution when the diffused light obtained by the light source device of the embodiment is viewed from the front. The graph of the illuminance distribution along the BB'line and CC'line of diffused light shown in FIG. 8A. Simulation result of two-dimensional illuminance distribution when the diffused light obtained by the light source device of the comparative example is viewed from the front. The graph of the illuminance distribution along the D-D'line and the E-E'line of the diffused light shown in FIG. 9A. The schematic diagram which shows the structure of the projector to which the light source device of an embodiment is applied.

Hereinafter, the light source device and the projector of the embodiment will be described with reference to the drawings. In each of the following figures, the scale of each member is different from the actual one in order to make each member recognizable in size.

FIG. 1 is a schematic view showing the configuration of the light source device 1. Hereinafter, the configuration of the light source device 1 will be described with reference to FIG.

As shown in FIG. 1, the light source device 1 is used, for example, as a light source of a projector, and includes a plurality of laser light sources 12 as solid-state light sources, a diffusion element 14, a light separation element 15, and a reflection element 16. Has.

The laser light source 12 emits a laser beam 11 as the first light. The light separation element 15 is arranged in the direction in which the laser light 11 is emitted from the laser light source 12, and the diffusion element 14 is further arranged in the subsequent stage.

Examples of the diffusing element 14 include a diffusing plate. The diffuser plate is a glass substrate having random irregularities formed on its surface, and the irregularities are formed on, for example, the surface of the glass substrate on the light emitting side. When the laser light 11 is incident on the unevenness, the laser light 11 is scattered and diffused. The diffusion element 14 is not limited to the above mode as long as the diffusion effect can be obtained. The diffusion element 14 is substantially orthogonal to the optical axis ax0 of the light source device 1, and is arranged so that the convergence region 141 described later is located on the optical axis ax0.

The light separation element 15 transmits a part of the light flux of the incident laser light 11 and reflects the rest. The optical separation element 15 is arranged between the light source device 1 and the diffusion element 14 so that the optical axis ax0 of the light source device 1 is orthogonal to the optical axis ax0 of the light source device 1 and the optical axis ax0 of the light source device 1 passes through the center thereof. In the present specification, among the light fluxes of the laser light 11 incident on the light separation element 15, the light flux transmitted through the light separation element 15 is referred to as a first light flux 17. Further, among the light fluxes of the laser light 11 incident on the light separation element 15, the light flux reflected by the light separation element 15 is referred to as a second light flux 18.

Examples of the optical separation element 15 include a half mirror, but the transmittance of the optical separation element 15 is not particularly limited and can be changed as appropriate. Further, the light separation element 15 is not limited to the half mirror, and for example, a polarization separation film or the like may be used. In this case, the laser light source 12 may be rotated around the emission direction of the laser light 11 as a rotation axis, or the polarization distribution of the laser light 11 emitted from the laser light source 12 may be changed by using a retardation plate.

The optical separation element 15 is provided so as to surround the transmission region 151 intersecting the optical axis ax0 of the light source device 1 and the outer periphery of the transmission region 151, and has a separation region 152 that transmits a part of the incident light and reflects the rest. Have. In the embodiment, an opening is formed in the center of the separation region 152, and this opening is used as a transmission region 151. However, the transmission region 151 may be composed of a transparent member capable of transmitting the laser beam 11. ..

The reflecting element 16 is arranged at a position where the second light flux 18 reflected by the light separating element 15 can be reflected toward the convergence region 141 of the diffusing element 14. The reflecting element 16 is an optical element having a negative power, and examples thereof include a convex mirror.

FIG. 2 is a schematic cross-sectional view of the structure of the laser light source 12 as viewed from the side. Hereinafter, the structure of the laser light source 12 will be described with reference to FIG.

As shown in FIG. 2, the laser light source 12 includes a package 120, a laser emitting element 10, and a condenser lens 13.

The package 120 fixes the laser emitting element 10 and the condensing lens 13 inside and protects them.

The laser emitting element 10 emits, for example, a blue laser beam 11. Examples of the blue laser light 11 include a laser light 11 having a peak wavelength of 455 nm. The condensing lens 13 condenses the laser light 11 emitted from the laser emitting element 10. By providing the condensing lens 13, the laser light 11 can be condensed and incident on the diffusing element 14, and the size of the pseudo light source formed on the diffusing element 14 can be reduced. As a result, for example, when the light source device 1 is mounted on the projector, the light utilization efficiency can be improved.

FIG. 3 is a schematic view of the laser light source 12 as viewed from the direction along the optical axis ax0. Hereinafter, the laser light source 12 will be described with reference to FIG.

As shown in FIG. 3, the plurality of laser light sources 12 include a first laser light source 121, a second laser light source 122, a third laser light source 123, and a fourth laser light source 124, each of which emits a blue laser light. And are included.

The first laser light source 121 emits the first laser light 11a. The second laser light source 122 emits the second laser light 11b. The third laser light source 123 emits the third laser light 11c. The fourth laser light source 124 emits the fourth laser beam 11d.

The first laser light source 121, the second laser light source 122, the third laser light source 123, and the fourth laser light source 124 are light-separated among the laser beams 11a, 11b, 11c, and 11d incident on the separation region 152 of the light separation element 15. The first light beam 17 that has passed through the element 15 is arranged so as to be focused on a local region in the diffuser element 14. That is, each laser light source 12 is arranged so as to be rotationally symmetric with respect to the optical axis ax0 of the light source device 1. Hereinafter, the region in the diffusion element 14 where the first luminous flux 17 collects light is referred to as a convergence region 141. Ideally, the convergence region 141 is a point, but it may be a region having a minute size. In the embodiment, the convergence region 141 is located in the center of the diffusion element 14 in a plan view and in the vicinity of the injection surface of the diffusion element 14 in a side view.

On the other hand, of the laser beams 11a, 11b, 11c, and 11d incident on the separation region 152 of the light separation element 15, the second light beam 18 reflected by the light separation element 15 is reflected again by the reflection element 16 and is reflected by the reflection element 16. It passes through the transmission region 151 of 15 and is incident on the diffusion element 14.

FIG. 4A is a schematic view showing the configuration of the first fixing member 161 for fixing the first laser light source 121 and the third fixing member 163 for fixing the third laser light source 123. FIG. 4B is a schematic view showing the configuration of the second fixing member 162 for fixing the second laser light source 122 and the fourth fixing member 164 for fixing the fourth laser light source 124. Hereinafter, the configurations of the first fixing member 161 to the fourth fixing member 164 will be described with reference to FIGS. 4A and 4B.

As shown in FIG. 4A, the first fixing member 161 is used to fix the first laser light source 121 at a predetermined angle. Specifically, in the first laser light source 121, the first fixing member 161 of the first laser light 11a so that the first luminous flux 17 passing through the light separation element 15 is incident on the convergence region 141 of the diffusion element 14. It is fixed to.

Further, the third fixing member 163 is used to fix the third laser light source 123 at a predetermined angle. Specifically, in the third laser light source 123, the third fixing member 163 of the third laser light 11c so that the first luminous flux 17 passing through the light separation element 15 is incident on the convergence region 141 of the diffusion element 14. It is fixed to.

As shown in FIG. 4B, the second fixing member 162 is used to fix the second laser light source 122 at a predetermined angle. Specifically, in the second laser light source 122, the second fixing member 162 of the second laser light 11b so that the first luminous flux 17 passing through the light separation element 15 is incident on the convergence region 141 of the diffusion element 14. It is fixed to.

Further, the fourth fixing member 164 is used to fix the fourth laser light source 124 at a predetermined angle. Specifically, in the fourth laser light source 124, the fourth fixing member 164 of the fourth laser beam 11d so that the first luminous flux 17 passing through the light separation element 15 is incident on the convergence region 141 of the diffusion element 14. It is fixed to.

The material of the first fixing member 161 to the fourth fixing member 164 is composed of a high heat conductive member such as copper that can exhaust the heat generated by the laser light source 12.

In this way, the laser beams 11a to 11d emitted from the laser light sources 121 to 124 form a predetermined angle with the optical axis ax0 of the light source device 1, and the first luminous flux 17 thereof is diffused. It is arranged so as to be incident on the convergence region 141 of the element 14. As a result, the laser beams 11a to 11d included in the first luminous flux 17 are diffused with the common convergence region 141 as the base point. Therefore, each of the laser beams 11a to 11d contained in the first luminous flux 17 is diffused by the diffusing element 14 with a similar diffusion distribution. In the embodiment, the angle formed by the laser beams 11a to 11d and the optical axis ax0 of the light source device 1 is 30 °.

Further, the laser light sources 121 to 124 are arranged rotationally symmetrically with respect to the optical axis ax0 of the light source device 1. As a result, the illuminance distribution of the diffused light in which the first luminous flux 17 composed of a part of the luminous fluxes of the laser beams 11a to 11d emitted from the laser light sources 121 to 124 is diffused by the diffuser element 14 is the light of the light source device 1. It becomes rotationally symmetric with respect to the axis ax0.

FIG. 5 is a schematic view showing the progress state of the laser beam 11 in the light source device 1. Hereinafter, the progress state of the laser beam 11 will be described with reference to FIG. Note that FIG. 5 shows the laser beams 11a and 11c emitted from the first laser light source 121 and the third laser light source 123 for the sake of simplicity, but is emitted from the second laser light source 122 and the fourth laser light source 124. The same applies to the laser beams 11b and 11d.

As shown in FIG. 5, in the first laser light 11a emitted from the first laser light source 121, the first laser light 11a emitted from the laser emitting element 10 is condensed by the condenser lens 13 to be a light separation element. It is incident on the separation region 152 of 15. The first laser beam 11a incident on the separation region 152 of the light separation element 15 is separated into two light fluxes by the light separation element 15. Specifically, the first laser beam 11a includes a first luminous flux 17a that passes through the separation region 152 of the light separation element 15 and a second luminous flux 18a that is reflected by the separation region 152 of the light separation element 15 and heads toward the reflection element 16. It is separated into two parts. In the embodiment, the light separation element 15 is a partially transmissive mirror having a transmittance of 80% and a reflectance of 20%. Further, in the embodiment, the reflecting element 16 is a convex mirror in which the apex and the center of curvature of the reflecting surface are on the optical axis ax0 of the light source device 1 and the reflecting surface is directed toward the diffusion element 14. That is, the reflecting element 16 has a negative power.

The first luminous flux 17a of the first laser light 11a transmitted through the light separation element 15 is focused on the convergence region 141 of the diffusion element 14 and diffused by the diffusion element 14 to become the first diffusion light 19a. On the other hand, the second luminous flux 18a reflected by the separation region 152 of the light separation element 15 is reflected again by the reflection element 16. The second luminous flux 18a of the first laser beam 11a reflected by the reflecting element 16 passes through the transmission region 151 of the light separation element 15 and is focused on the convergence region 141 of the diffusion element 14. The second luminous flux 18a of the first laser light 11a focused on the convergence region 141 of the diffusing element 14 is diffused by the diffusing element 14 to become the second diffused light 20a.

Similarly, in the third laser light 11c emitted from the third laser light source 123, the third laser light 11c emitted from the laser emitting element 10 is condensed by the condenser lens 13, and the separation region of the light separation element 15 is condensed. It enters the 152 and is separated into two light sources in the separation region 152. Then, similarly to the first laser light 11a, in the diffusing element 14, the first diffused light 19c which is the diffused light of the first luminous flux 17c of the third laser light 11c and the diffused light of the second luminous flux 18c of the third laser light 11c. It becomes the second diffused light 20c. In FIG. 5, the first luminous flux 17a, 17c and the first diffused light 19a, 19c are indicated by broken lines, and the second luminous flux 18a, 18c and the second diffused light 20a, 20c are indicated by a two-dot chain line.

Although not shown, the second laser light 11b emitted from the second laser light source 122 includes the first diffused light 19b, which is the diffused light of the first light beam 17b transmitted through the light separating element 15, and the light separating element. It becomes the second diffused light 20b which is the diffused light of the second light source 18b reflected by 15. Further, the fourth laser light 11d emitted from the fourth laser light source 124 is the first diffused light 19d, which is the diffused light of the first light beam 17d transmitted through the light separating element 15, and the second diffused light reflected by the light separating element 15. It becomes the second diffused light 20d which is the diffused light of the light source 18d. From this point onward, the first diffused light 19a, 19b, 19c, 19d are also referred to as the first diffused light 19 without distinguishing each of them, and the second diffused light 20a, 20b, 20c, 20d is the second diffused light. Also written as 20.

Here, the first laser light source 121 and the third laser light source 123 are arranged rotationally symmetrically with respect to the optical axis ax0 of the light source device 1. Therefore, the first incident angle formed by the first laser beam 11a with respect to the optical axis ax0 of the light source device 1 and the second incident angle formed by the third laser beam 11c with respect to the optical axis ax0 of the light source device 1 are equal. Become. Therefore, the incident angle of the first luminous flux 17a of the first laser beam 11a with respect to the diffusing element 14 and the incident angle of the first luminous flux 17c of the third laser beam 11c with respect to the diffusing element 14 are also equal.

Further, the convergence region 141 in which the first luminous flux 17a of the first laser light 11a is focused and the convergence region 141 in which the first luminous flux 17c of the third laser light 11c is focused are the centers of the ejection surfaces of the diffusion element 14. Approximately matches. Therefore, the illuminance distributions of the first diffused light 19a of the first laser light 11a and the first diffused light 19c of the third laser light 11c are rotationally symmetric with respect to the optical axis ax0 of the light source device 1.

Further, since the first incident angle and the second incident angle are equal and the light separation element 15 is arranged so as to be orthogonal to the optical axis ax0 of the light source device 1, reflection is reflected in the separation region 152 of the light separation element 15. The reflection angle of the second light source 18a of the first laser light 11a and the reflection angle of the second light source 18c of the third laser light 11c reflected by the separation region 152 of the light separation element 15 are also equal.

In addition, in the embodiment, the convex mirror which is the reflecting element 16 is arranged so that its apex and the center of curvature are on the optical axis ax0 of the light source device 1, and its reflecting surface is arranged with respect to the optical axis ax0. It is rotationally symmetric. Therefore, the angle of incidence of the first laser beam 11a on the reflecting element 16 of the second luminous flux 18a and the angle of incidence of the third laser beam 11c on the reflecting element 16 of the second luminous flux 18c are also equal. Therefore, the reflection angle of the first laser beam 11a at the reflecting element 16 of the second luminous flux 18a and the reflection angle of the third laser beam 11c at the reflecting element 16 of the second luminous flux 18c are also equal.

Here, the curvature of the convex mirror, which is the reflecting element 16, is set so that the light flux reflected by the reflecting element 16 is focused on the convergence region 141 of the diffusing element 14. Therefore, the third incident angle, which is the angle formed by the second luminous flux 18a of the first laser beam 11a incident on the diffuser element 14 and the optical axis ax0 of the light source device 1, is the first laser beam 11a incident on the diffuser element 14. It is smaller than the first incident angle, which is the angle formed by the first luminous flux 17a of the light source device 1 and the optical axis ax0 of the light source device 1. Therefore, regarding the angle formed by the second diffused light 20a of the first laser beam 11a and the optical axis ax0 of the light source device 1, the first diffused light 19a of the first laser beam 11a and the optical axis ax0 of the light source device 1 are also formed. It is smaller than the angle formed by.

Here, the reason why the reflecting element 16 is a convex mirror having a negative power will be described with reference to FIG.

As can be seen from FIG. 5, the optical path lengths of the second luminous fluxes 18a and 18c that are reflected by the separation region 152 of the light separation element 15 and are reflected again by the reflection element 16 and then incident on the diffusion element 14 are the optical path lengths of the light separation element 15. It is longer than the optical path lengths of the first light fluxes 17a and 17c that are transmitted and incident on the diffusing element 14. When the reflecting element 16 does not have a negative power, the second luminous fluxes 18a and 18c are focused before they are incident on the diffusing element 14, so that the focused spot size of the second luminous flux 18 at the position of the convergence region 141 is large. Become. When the condensing spot becomes large, the light utilization efficiency of the optical system incorporating the light source device 1 decreases. On the other hand, when the reflecting element 16 has a negative power, the condensing position of the second luminous flux 18 is extended. Therefore, if the reflecting element 16 having a negative power is appropriately arranged on the optical path of the second luminous flux 18, the second luminous flux 18 can be focused on the convergence region 141 of the diffusing element 14.

Similarly, the fourth incident angle, which is the angle formed by the second luminous flux 18c of the third laser beam 11c incident on the diffuser element 14 and the optical axis ax0 of the light source device 1, is the third laser beam incident on the diffuser element 14. It is smaller than the second incident angle, which is the angle formed by the first luminous flux 17c of 11c and the optical axis ax0 of the light source device 1. Therefore, regarding the angle formed by the second diffused light 20c of the third laser beam 11c and the optical axis ax0 of the light source device 1, the first diffused light 19c of the third laser beam 11c and the optical axis ax0 of the light source device 1 are also formed. It is smaller than the angle formed by.

The difference in the size of the angle formed by the optical axis ax0 of the light source device 1 and the diffused light appears as a difference in the illuminance distribution of the diffused light emitted from the diffused element 14. The difference in the illuminance distribution between the first diffused light 19 and the second diffused light 20 will be described below.

First, the first diffused light 19 will be described. The first diffused light 19 having a large angle with the optical axis ax0 of the light source device 1 has an illuminance distribution such that the peak of the illuminance comes to a position away from the optical axis ax0 of the light source device 1. Therefore, the first diffused lights 19a to 19d corresponding to the laser lights 11a to 11d emitted from the laser light sources 121 to 124 hardly overlap each other. Therefore, the illuminance distribution of the entire first diffused light 19 emitted from the diffused element 14 becomes smaller in the vicinity of the optical axis ax0 of the light source device 1.

Subsequently, the second diffused light 20 will be described. The second diffused light 20 having a small angle with the optical axis ax0 of the light source device 1 has an illuminance distribution such that the peak of the illuminance is closer to the optical axis ax0 of the light source device 1 than the first diffused light 19. Take. Therefore, most of the second diffused lights 20a to 20d corresponding to the laser lights 11a to 11d emitted from the laser light sources 121 to 124 overlap each other in the vicinity of the optical axis ax0 of the light source device 1. Therefore, the illuminance distribution of the entire second diffused light 20 emitted from the diffused element 14 is very large in the vicinity of the optical axis ax0 of the light source device 1, and the illuminance is attenuated toward the periphery.

As described above, in the light source device 1 of the embodiment, the first light flux 17 transmitted through the light separation element 15 and the second light flux 18 reflected by the light separation element 15 are incident on the diffusion element 14 at different incident angles. To do. Therefore, the illuminance distribution of the first diffused light 19 which is the diffused light of the first luminous flux 17 and the illuminance distribution of the second diffused light 20 which is the diffused light of the second luminous flux 18 are also different from each other. By superimposing these diffused lights having different illuminance distributions, it is possible to complement each other in the insufficient illuminance region in each diffused light, and it is possible to suppress illuminance unevenness. As a result, the diffuser element 14 emits diffused light 140, which is a composite light of the first diffused light 19 and the second diffused light 20 that have been diffused and transmitted, and has a uniform illuminance distribution.

FIG. 6 is a schematic view showing the configuration of the light source device 1 when the illuminance distribution of the embodiment is simulated. FIG. 7 is a schematic view showing the configuration of the light source device 101 when the illuminance distribution of the comparative example is simulated.

In addition to the configuration shown in FIG. 1, the light source device 1 and the light source device 101 shown in FIGS. 6 and 7 include a first lens 9a and a second lens 9b that parallelize the diffused light 140 diffused by the diffuser element 14. ing.

The configuration of the light source device 101 of the comparative example shown in FIG. 7 is the configuration of the light source device 1 in the embodiment excluding the light separation element 15 and the reflection element 16, and the other configurations are the same as those of the embodiment. The same is true.

8A and 8B are diagrams showing simulation results of the illuminance distribution of the light source device 1 of the embodiment. Specifically, FIG. 8A is a diagram of a two-dimensional illuminance distribution when the diffused light 140 obtained by the light source device 1 of the embodiment is viewed from a direction along the optical axis ax0 of the light source device 1. FIG. 8B is a graph showing the illuminance distribution along the BB'line and the illuminance distribution along the CC'line of the diffused light 140 shown in FIG. 8A.

The figure shown in FIG. 8A shows the result of simulating the illuminance distribution in the configuration of the light source device 1 of the embodiment in black and white gradation. The intersection of the BB'line and the CC' line is the optical axis ax0 of the light source device 1.

The illuminance distribution shown in FIG. 8A indicates that the irradiance increases as the color becomes whiter. In the graph shown in FIG. 8B, the horizontal axis shows the distance from the optical axis ax0, and the vertical axis shows the magnitude of irradiance. As can be seen from the illuminance distribution shown in FIG. 8B, in the simulation of the illuminance distribution based on the configuration of the light source device 1 of the embodiment, there is no remarkable peak in the illuminance, and the illuminance distribution is uniform over a wide range of the diffused light 140. You can see that.

On the other hand, FIGS. 9A and 9B are diagrams showing simulation results of the illuminance distribution of the light source device 101 of the comparative example. Specifically, FIG. 9A is a diagram of a two-dimensional illuminance distribution when the diffused light 140 obtained by the light source device 101 of the comparative example is viewed from a direction along the optical axis of the light source device 101. FIG. 9B is a graph showing the illuminance distribution along the D-D'line and the illuminance distribution along the E-E'line of the diffused light shown in FIG. 9A.

The figure shown in FIG. 9A shows the result of simulating the illuminance distribution in the configuration of the light source device 101 of the comparative example in black and white gradation. The intersection of the D-D'line and the E-E'line is the optical axis of the light source device 101.

The illuminance distribution shown in FIG. 9A indicates that the irradiance increases as the color becomes whiter. In the graph shown in FIG. 9B, the horizontal axis shows the distance from the optical axis ax0, and the vertical axis shows the magnitude of irradiance. As can be seen from the illuminance distribution shown in FIG. 9B, in the simulation of the illuminance distribution based on the configuration of the light source device 101 of the comparative example, there are two peaks at positions away from the optical axis, while the illuminance is located near the optical axis. It can be seen that there is a decrease and the illuminance distribution is uneven.

As described above, in the light source device 1 of the embodiment, the light separation element 15 and the reflection element 16 are arranged between the laser light source 12 and the diffusion element 14 as compared with the light source device 101 of the comparative example. Therefore, diffused light 140 having a uniform illuminance distribution can be obtained.

FIG. 10 is a schematic view showing the configuration of the projector 2 to which the light source device 1 of the embodiment is applied. Hereinafter, the configuration of the projector 2 will be described with reference to FIG.

As shown in FIG. 10, the projector 2 is a projection type image display device that displays a color image on the screen SCR, and includes a blue lighting device 21, a yellow lighting device 22, a color separation optical system 3, and light. It includes a modulator 4B, an optical modulator 4R, an optical modulator 4G, a composite optical system 5, and a projection optical system 6 as a projection lens.

The blue illumination device 21 includes a light source device 1, a first pickup optical system 211, a first integrator optical system 212, and a first superimposing lens 213, which are sequentially arranged on the optical axis ax1. ing.

The blue light BL1 emitted from the light source device 1 is parallelized by the first pickup optical system 211 and incident on the first integrator optical system 212. The first integrator optical system 212 is composed of, for example, a lens array 212a and a lens array 212b. Each of the lens arrays 212a and 212b includes a plurality of small lenses arranged in an array.

The blue light BL1 transmitted through the first integrator optical system 212 is incident on the first superimposing lens 213. The first superimposing lens 213 cooperates with the first integrator optical system 212 to make the illuminance distribution by the blue light BL1 in the illuminated region uniform. In this way, the blue light BL1 is emitted from the blue lighting device 21.

The yellow illumination device 22 includes a light source device 1b, a second integrator optical system 223, a polarization conversion element 224, and a second superimposing lens 225.

The light source device 1b includes a light source unit 231, a dichroic mirror 7b, a second pickup optical system 232, and a fluorescence light emitting element 233. In the yellow lighting device 22, the light source unit 231 and the dichroic mirror 7b are sequentially arranged on the optical axis ax2.

Further, the fluorescence light emitting element 233, the second pickup optical system 232, the dichroic mirror 7b, the second integrator optical system 223, the polarization conversion element 224, and the second superimposing lens 225 are sequentially arranged on the optical axis ax3. Has been done. The optical axis ax1, the optical axis ax2, and the optical axis ax3 are in the same plane, and the optical axis ax2 and the optical axis ax3 are orthogonal to each other. The optical axis ax1 corresponds to the illumination optical axis of the blue illumination device 21, and the optical axis ax3 corresponds to the illumination optical axis of the yellow illumination device 22.

The light source unit 231 includes a plurality of laser light emitting elements 10b that emit blue light rays BL2, and a plurality of collimator lenses 32. The plurality of collimator lenses 32 are provided in each optical path of the plurality of laser light emitting elements 10b. The collimator lens 32 is composed of a convex lens. The collimator lens 32 parallelizes the light rays emitted from the corresponding laser emitting element 10b. Based on such a configuration, the light source unit 231 emits a plurality of parallelized light rays BL2.

The dichroic mirror 7b is arranged so as to form an angle of 45 ° with respect to the optical axis ax2 and the optical axis ax3, respectively. The dichroic mirror 7b has a color separation function that reflects the blue light BL2 and transmits the fluorescent light YL emitted from the fluorescent light emitting element 233. The blue light ray BL2 emitted from the light source unit 231 is reflected by the dichroic mirror 7b and is incident on the fluorescence light emitting element 233 via the second pickup optical system 232.

The fluorescent light emitting element 233 is excited by the blue light BL2 and emits fluorescent light (yellow light) YL having a peak wavelength in the wavelength range of, for example, 500 to 700 nm. The fluorescent light YL is emitted toward the second pickup optical system 232. The second pickup optical system 232 is located near the fluorescence emitting surface of the fluorescence emitting element 233 in order to parallelize the fluorescence light YL emitted from the fluorescence emitting element 233.

The fluorescent light YL parallelized by the second pickup optical system 232 passes through the dichroic mirror 7b and is incident on the second integrator optical system 223. Like the first integrator optical system 212, the second integrator optical system 223 is also composed of a plurality of lens arrays, and each of the lens arrays includes a plurality of small lenses arranged in an array.

The fluorescent light YL transmitted through the second integrator optical system 223 is incident on the polarization conversion element 224. The polarization conversion element 224 is composed of a plurality of polarization separation membranes and a plurality of retardation plates. The polarization conversion element 224 converts unpolarized fluorescent light YL into linearly polarized light.

The fluorescent light YL transmitted through the polarization conversion element 224 is incident on the second superimposing lens 225. Similar to the first superimposed lens 213, the second superimposed lens 225 also cooperates with the second integrator optical system 223 to make the illuminance distribution by the fluorescent light YL in the illuminated region uniform. In this way, the yellow lighting device 22 emits fluorescent light YL.

The blue lighting device 21 emits blue light BL1 toward the color separation optical system 3. The yellow lighting device 22 emits the red light LR and the fluorescent light YL including the green light LG toward the color separation optical system 3.

The color separation optical system 3 includes a dichroic mirror 7r, a total reflection mirror 8b, a total reflection mirror 8r, and a total reflection mirror 8g. The color separation optical system 3 guides the blue light BL1 emitted from the light source device 1 to the light modulation device 4B. Further, the color separation optical system 3 separates the yellow fluorescent light YL emitted from the yellow lighting device 22 into red light LR and green light LG, and guides them to the corresponding light modulation device 4R and light modulation device 4G.

The dichroic mirror 7r separates the fluorescent light YL from the yellow lighting device 22 into red light LR and green light LG. The dichroic mirror 7r reflects the red light LR and transmits the green light LG.

The total reflection mirror 8b reflects the blue light BL1 toward the light modulation device 4B. The total reflection mirror 8r reflects the red light LR toward the light modulation device 4R. The total reflection mirror 8g reflects the green light LG toward the light modulator 4G.

The light modulation device 4B modulates the blue light BL1 according to the image information to form blue image light. The optical modulation device 4R modulates the red light LR according to the image information to form the red image light. The light modulator 4G modulates the green light LG according to the image information to form the green image light.

For the optical modulation device 4B, the optical modulation device 4R, and the optical modulation device 4G, for example, a transmissive liquid crystal panel is used. Further, polarizing plates (not shown) are arranged on each of the incident side and the ejection side of the liquid crystal panel.

Further, a field lens 23B, a field lens 23R, and a field lens 23G are arranged on the incident side of the light modulation device 4B, the light modulation device 4R, and the light modulation device 4G, respectively.

Each image light from the optical modulation device 4B, the optical modulation device 4R, and the optical modulation device 4G is incident on the synthetic optical system 5. The synthetic optical system 5 synthesizes each image light and emits the combined image light toward the projection optical system 6. For example, a cross dichroic prism is used in the synthetic optical system 5.

The projection optical system 6 is composed of a group of projection lenses, and magnifies and projects the image light synthesized by the composite optical system 5 toward the screen SCR. As a result, an enlarged color image is displayed on the screen SCR.

As described above, according to the light source device 1 and the projector 2 of the embodiment, the following effects can be obtained.

(1) According to the embodiment, the first light flux 17 transmitted through the light separation element 15 and the second light flux 18 reflected by the light separation element 15 are incident on the diffusion element 14 at different incident angles. Therefore, the illuminance distribution of the first diffused light 19 which is the diffused light of the first luminous flux 17 and the illuminance distribution of the second diffused light 20 which is the diffused light of the second luminous flux 18 are also different from each other. By superimposing these diffused lights having different illuminance distributions, it is possible to complement each other in the insufficient illuminance region in each diffused light, and it is possible to suppress illuminance unevenness.

(2) According to the embodiment, since the light separation element 15 has a separation region 152 that reflects the second light flux 18 and a transmission region 151 through which the second light flux 18 passes, the laser light source 12 is moved to the separation region 152. The second luminous flux 18 of each incident laser beam 11 is reflected toward the reflecting element 16, while the second luminous flux 18 reflected by the reflecting element 16 and directed toward the diffusing element 14 can pass through the transmission region 151.

(3) According to the embodiment, since the reflecting element 16 has a negative power, the condensing position of the second luminous flux 18 whose optical path length is longer than that of the optical path length of the first luminous flux 17 can be extended. , The second luminous flux 18 can be focused on the same convergence region 141 as the first luminous flux 17. Therefore, the spot size of the second luminous flux 18 in the convergence region 141 can be reduced, so that the light utilization efficiency can be improved.

(4) According to the embodiment, the first fixing member 161 to the fourth fixing member 164 for fixing the laser light source 12 are provided, and the first fixing member 161 to the fourth fixing member 164 are the first fixed members 164 emitted from the laser light source 12. The laser light source 12 is fixed so that 1 light flux 17 is directed toward the convergence region 141. Therefore, all of the first luminous flux 17 of the laser beams 11a to 11d emitted from the laser light sources 121 to 124 are diffused with the convergence region 141 of the emission surface of the diffusion element 14 as the base point. Therefore, the illuminance distribution of the diffused light over the first luminous flux 17 can be shaped symmetrically with respect to the optical axis ax0 of the light source device 1.

(5) According to the embodiment, since the laser beam 11 is incident on the light modulation devices 4R, 4G, and 4B as the liquid crystal device with a uniform illuminance distribution, it is possible to provide the projector 2 with less uneven illuminance.

(Modification example)
Moreover, the said embodiment may be changed as follows.

In the above embodiment, the condenser lens 13 is configured as a part of the laser light source 12, but the present invention is not limited to this. For example, the condenser lens 13 may be separately arranged at a position where the laser light 11 emitted from the laser light source 12 can be focused on the convergence region 141 of the diffusion element 14.

In the above embodiment, four laser light sources 12 are used, but the present invention is not limited to this configuration, and the laser light sources 12 may be arranged rotationally symmetrically with respect to the optical axis ax0 of the light source device 1. That is, it suffices that two or more laser light sources 12 are arranged. By changing the number of the laser light sources 12, the distributed shape of the diffused light 140 obtained by the light source device 1 can be changed according to the purpose.

In the above embodiment, the light source device 1 is used only for the blue optical path of the projector 2, but the present invention is not limited to this, and if the red light source and the green light source are laser light sources, the red optical path and the green optical path are also independent, and the projector 2 is used. It may be used in the same configuration as the blue optical path of. According to this, since the illuminance distribution emitted from the pickup optical system can obtain the same illuminance distribution in the red optical path, the green optical path, and the blue optical path, it is possible to project the image light with less color unevenness onto the screen SCR. ..

The contents derived from the embodiment are described below.

The light source device includes a plurality of solid light sources that emit the first light, an optical separation element that transmits the first light beam of the first light and reflects the second light beam of the first light, and a subsequent stage of the light separation element. A diffusing element for diffusing an incident light source and a reflecting element for reflecting the second light source reflected by the light separating element toward the diffusing element. The light is focused on the converging region of the diffusing element, the reflecting element condenses the second light beam on the converging region, and the plurality of solid light sources are substantially orthogonal to the diffusing element and are on an axis passing through the converging region. It is characterized in that it is arranged so as to be rotationally symmetric.

According to this configuration, the first light flux transmitted through the light separation element and the second light flux reflected by the light separation element are incident on the diffusion element at different angles of incidence. Therefore, the illuminance distribution of the first diffused light, which is the diffused light of the first luminous flux, and the illuminance distribution of the second diffused light, which is the diffused light of the second luminous flux, are also different from each other. By superimposing these diffused lights having different illuminance distributions, it is possible to complement each other in the insufficient illuminance region in each diffused light, and it is possible to suppress illuminance unevenness.

In the above light source device, the light separation element is reflected by the reflection element and a separation region in which the first light is incident and separates the first light into the first light flux and the second light flux. It is desirable to have a transmission region through which the second luminous flux passes.

According to this configuration, the second luminous flux of each laser beam incident on the separation region from the laser light source is reflected toward the reflecting element, while the second luminous flux reflected by the reflecting element and directed toward the diffusing element passes through the transmission region. can do.

In the above light source device, it is desirable that the reflecting element has a negative power.

According to this configuration, the focusing position of the second luminous flux whose optical path length is longer than that of the optical path length of the first luminous flux can be extended, so that the second luminous flux is focused on the convergence region of the first luminous flux. Can be done. Therefore, the spot size of the second luminous flux in the convergence region can be reduced, so that the light utilization efficiency can be improved.

The light source device includes a fixing member for fixing the plurality of solid light sources, and the fixing member comprises the plurality of fixing members so that the first light flux emitted from the plurality of solid light sources is incident on the convergence region. It is desirable to fix the solid light source.

According to this configuration, all of the first luminous flux of each laser beam emitted from the laser light source is diffused with the convergence region of the diffusing element as a base point. Therefore, the illuminance distribution of the diffused light of the entire first luminous flux can be made symmetrical with respect to the optical axis of the light source device.

The projector of the present application is characterized by including the above-mentioned light source device, a light modulation device that modulates the light emitted from the light source device, and a projection lens that projects the light emitted from the light modulation device. ..

According to this configuration, since the laser light is incident on the liquid crystal device with a uniform illuminance distribution, it is possible to provide a projector with less illuminance unevenness.

1,1b ... light source device, 2 ... projector, 3 ... color separation optical system, 4B, 4G, 4R ... optical modulator, 5 ... synthetic optical system, 6 ... projection optical system, 7b, 7r ... dichroic mirror, 8b, 8g , 8r ... Total reflection mirror, 9a ... 1st lens, 9b ... 2nd lens, 10,10b ... Laser emitting element, 11 ... Laser light, 11a ... 1st laser light, 11b ... 2nd laser light, 11c ... 3rd Laser light, 11d ... 4th laser light, 12 ... Laser light source, 13 ... Condensing lens, 14 ... Diffusing element, 15 ... Light separating element, 16 ... Reflecting element, 17, 17a to 17d ... First light beam, 18, 18a ~ 18d ... Second light beam, 19, 19a ~ 19d ... First diffused light, 20, 20a ~ 20d ... Second diffused light, 21 ... Blue lighting device, 22 ... Yellow lighting device, 23B, 23G, 23R ... Field Lens, 32 ... Collimeter lens, 120 ... Package, 121 ... 1st laser light source, 122 ... 2nd laser light source, 123 ... 3rd laser light source, 124 ... 4th laser light source, 140 ... Diffuse light, 141 ... Convergence region, 151 ... Transmission region, 152 ... Separation region, 161 ... First fixing member, 162 ... Second fixing member, 163 ... Third fixing member, 164 ... Fourth fixing member, 211 ... First pickup optical system, 212 ... First Integrator optical system, 212a, 212b ... Lens array, 213 ... 1st superimposition lens, 223 ... 2nd integrator optical system, 224 ... Polarization conversion element, 225 ... 2nd superimposition lens, 231 ... Light source unit, 232 ... 2nd pickup optical System, 233 ... Fluorescent light emitting element, BL1 ... Blue light, LG ... Green light, LR ... Red light, YL ... Fluorescent light, ax0, ax1, ax2, ax3 ... Optical axis, SCR ... Screen.

Claims (5)

Multiple solid-state light sources that emit the first light,
An optical separation element that transmits the first luminous flux of the first light and reflects the second luminous flux of the first light.
A diffusing element provided after the optical separation element and diffusing an incident luminous flux,
A reflecting element that reflects the second luminous flux reflected by the light separating element toward the diffusing element is provided.
The first luminous flux is focused on the convergence region of the diffusing element,
The reflecting element focuses the second luminous flux on the convergent region.
A light source device characterized in that the plurality of solid-state light sources are arranged so as to be substantially orthogonal to the diffusion element and rotationally symmetric with respect to an axis passing through the convergence region. The light source device according to claim 1.
The optical separation element has a separation region in which the first light is incident and separates the first light into the first light source and the second light source, and the second light beam reflected by the reflection element. A light source device characterized by having a transparent region through which it passes. The light source device according to claim 1 or 2.
The light source device is characterized in that the reflecting element has a negative power. The light source device according to any one of claims 1 to 3.
A fixing member for fixing the plurality of solid light sources is provided.
The fixing member is a light source device for fixing the plurality of solid light sources so that the first light flux emitted from the plurality of solid light sources is incident on the convergence region. The light source device according to any one of claims 1 to 4.
An optical modulation device that modulates the light emitted from the light source device, and
A projection lens that projects the light emitted from the light modulator and
A projector characterized by being equipped with.

Images