JP2019032471A - Luminaire and projector - Google Patents

Abstract

To provide a compact luminaire that can easily ensure telecentricity.SOLUTION: A luminaire of the present invention comprises: a light source unit that includes a plurality of light emitting elements and emits a bundle of rays consisting of a plurality of rays; a collimation optical system that is provided on a light path of the bundle of rays emitted from the light source unit; and a bundle of rays compression optical system that is provided on the light path of the bundle of rays passing through the collimation optical system. The bundle of rays compression optical system includes a first lens, a second lens, a third lens, and a fourth lens arranged in order from an incident side of the bundle of rays; the first lens is formed of a spherical lens having a positive power; the second lens is formed of a first anamorphic lens having a positive power; the third lens is formed of a second anamorphic lens having a negative power; and the fourth lens is formed of a spherical lens.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lighting device and a projector.

  For example, as a lighting device used for a projector, a lighting device using a light emitting element such as a semiconductor laser has been proposed. Patent Document 1 below discloses a projector including an illumination optical system including a two-dimensional laser array light source, an integrator optical system, a plurality of first lenses, and a plurality of second lenses. In this projector, a plurality of lights emitted from the two-dimensional laser array light source are superimposed by an integrator optical system and irradiated onto a light modulation element such as a liquid crystal panel.

JP 2013-15762 A

  In general, the aspect ratio of the light modulation element is different from the aspect ratio of the light emitted from the laser array light source, and the size of the light modulation element is different from the size of the light emitted from the laser array light source. Therefore, when illuminating the light modulation element, an optical system for adjusting the aspect ratio and size of the light emitted from the laser array light source is necessary. If the integrator optical system is omitted for the purpose of reducing the size of the lighting device and reducing the cost, the size must be largely changed while adjusting the cross-sectional shape of the light from the laser array light source. Therefore, even if the aspect ratio and size of the light from the laser array light source can be adjusted, it is difficult to ensure the telecentricity of the light incident on the light modulation element.

  One aspect of the present invention is made to solve the above-described problem, and an object of the present invention is to provide a small lighting device that can easily ensure telecentricity. Another aspect of the present invention is to provide a projector including the lighting device.

  In order to achieve the above object, an illumination device according to an aspect of the present invention includes a light source unit that includes a plurality of light emitting elements and that emits a light bundle composed of a plurality of lights, and the light beam emitted from the light source unit. A collimating optical system provided on the optical path of the bundle, and a light bundle compression optical system provided on the optical path of the light bundle that has passed through the collimating optical system. The light bundle compression optical system includes a first lens, a second lens, a third lens, and a fourth lens arranged in order from the incident side of the light bundle, and the first lens is a positive lens The second lens is composed of a first anamorphic lens having positive power, the third lens is composed of a second anamorphic lens having negative power, and the fourth lens is composed of a spherical lens having power. The lens is a spherical lens.

  According to the illumination device of one aspect of the present invention, an afocal optical system is configured by the first lens and the fourth lens, both of which are spherical lenses, and the light beam from the light source unit is formed by the afocal optical system. Is reduced in size while maintaining parallelism. In addition, the second lens and the third lens, both of which are anamorphic lenses, form a shape adjusting optical system, and the shape adjusting optical system adjusts the cross-sectional shape and the aspect ratio of the light beam from the light source unit. As described above, since the shape adjusting optical system composed of two anamorphic lenses is incorporated in the afocal optical system composed of two spherical lenses, it is possible to realize a small illumination device that can easily ensure telecentricity. it can.

  In the illumination device according to one aspect of the present invention, the first anamorphic lens may be composed of a first cylindrical lens, and the second anamorphic lens may be composed of a second cylindrical lens.

  According to this configuration, the cost of the lighting device can be reduced.

  In the illumination device according to one aspect of the present invention, each of the plurality of light emitting elements is formed of a semiconductor laser, and the collimating optical system is provided at a stage subsequent to a third cylindrical lens and the third cylindrical lens. A fourth cylindrical lens, and the generatrix of the third cylindrical lens and the generatrix of the fourth cylindrical lens may be orthogonal to each other.

  According to this configuration, compared to the case where a collimating optical system including a plurality of spherical lenses is used, the interval between the plurality of lights after the size of the light bundle is reduced is reduced, so that the illuminance uniformity of the light bundle is reduced. Can be increased.

  In the illumination device according to one aspect of the present invention, each of the plurality of light emitting elements includes a semiconductor laser, the collimating optical system includes a plurality of convex lenses, and a longitudinal direction of a light emission region of the semiconductor laser is the first direction. It may be parallel to the generatrix of one cylindrical lens and the generatrix of the second cylindrical lens.

  According to this configuration, as compared with the case where the longitudinal direction of the light emission region of the semiconductor laser is perpendicular to the bus line of the first cylindrical lens and the bus bar of the second cylindrical lens, the plurality of light beams after the size of the light beam is reduced Therefore, the uniformity of the illuminance of the light bundle can be improved.

  The illumination device according to one aspect of the present invention may further include a diffusing element that diffuses the light beam that has passed through the light beam compression optical system.

  According to this configuration, since the light beam that has passed through the light beam compression optical system is diffused by the diffusing element, the illuminance uniformity of the light beam can be improved.

  A projector according to an aspect of the present invention includes an illumination device according to an aspect of the present invention, a light modulation device that forms image light by modulating light from the illumination device according to image information, and the image light. A projection optical system.

  According to this configuration, it is possible to realize a small projector with excellent display quality.

  In the projector according to one aspect of the present invention, the light modulation device includes an image forming region having a longitudinal direction, the first anamorphic lens includes a first cylindrical lens, and the second anamorphic lens includes a second anamorphic lens. The first and second cylindrical lenses may be parallel to the longitudinal direction of the first cylindrical lens and the second cylindrical lens.

  According to this configuration, it is easy to adjust the aspect ratio and size of the light beam according to the aspect ratio and size of the image forming area.

It is a schematic block diagram of the projector of 1st Embodiment. It is a perspective view of the illuminating device of 1st Embodiment. It is a top view of an illuminating device. It is a side view of an illuminating device. It is a perspective view of a light emitting element. It is a simulation result which shows the intensity distribution of the light beam in the front | former stage of a light beam compression optical system. It is a simulation result which shows the intensity distribution of the light beam in the back | latter stage of a light beam compression optical system. It is a simulation result which shows the intensity distribution of the light beam in an image formation area. It is a perspective view of the illuminating device of 2nd Embodiment. It is a simulation result which shows the intensity distribution of the light beam in the front | former stage of a light beam compression optical system. It is a simulation result which shows the intensity distribution of the light beam in the back | latter stage of a light beam compression optical system. It is a simulation result which shows the intensity distribution of the light beam in an image formation area.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of a projector according to the present embodiment.
As shown in FIG. 1, the projector 100 includes a red light illumination device 101R, a green light illumination device 101G, a blue light illumination device 101B, a red light liquid crystal light valve 102R, and a green light liquid crystal light valve. 102G, a blue light liquid crystal light valve 102B, a field lens 106B, a field lens 106G, a field lens 106R, a color composition element 103, and a projection optical system 104.

  In the present embodiment, each of the red light illumination device 101R, the green light illumination device 101G, and the blue light illumination device 101B corresponds to an “illumination device” in the claims. Each of the liquid crystal light valve for red light 102R, the liquid crystal light valve for green light 102G, and the liquid crystal light valve for blue light 102B corresponds to the “light modulation device” in the claims.

The projector 100 generally operates as follows.
A light bundle LR composed of a plurality of red laser beams emitted from the red light illumination device 101R enters the red light liquid crystal light valve 102R via the field lens 106R and is modulated. A light bundle LG made up of a plurality of green laser beams emitted from the green light illumination device 101G is incident on the green light liquid crystal light valve 102G via the field lens 106G and modulated. A light beam LB composed of a plurality of blue laser lights emitted from the blue light illumination device 101B is incident on the blue light liquid crystal light valve 102B via the field lens 106B and modulated.

  Although not shown, the blue light liquid crystal light valve 102B includes a liquid crystal panel in which a liquid crystal layer is sandwiched between a pair of glass substrates, a light incident side polarizing plate disposed on the light incident side of the liquid crystal panel, and a liquid crystal A light emission side polarizing plate disposed on the light emission side of the panel. Further, the blue light liquid crystal light valve 102B includes a rectangular image forming region having a longitudinal direction and a lateral direction. The operation mode of the liquid crystal panel is not particularly limited, such as a TN mode, a VA mode, and a horizontal electric field mode. The liquid crystal light valve for green light 102G and the liquid crystal light valve for red light 102R have the same configuration. The blue light liquid crystal light valve 102B forms image light by modulating light from the blue light illumination device 101B according to image information. The same applies to the green light liquid crystal light valve 102G and the red light liquid crystal light valve 102R.

  The red light modulated by the red light liquid crystal light valve 102R, the green light modulated by the green light liquid crystal light valve 102G, and the blue light modulated by the blue light liquid crystal light valve 102B are combined by the color combining element 103. Is done. The color synthesizing element 103 is composed of, for example, a cross dichroic prism. The light synthesized by the color synthesizing element 103 is emitted as image light and then enlarged and projected onto the screen SCR by the projection optical system 104. The projection optical system 104 includes a plurality of lenses. In this way, a full color image is displayed.

  Hereinafter, the direction in which the light beam is emitted from the blue light illumination device 101B is defined as the Y direction, the direction in which the light is emitted from the projection optical system 104 is defined as the X direction, and the direction perpendicular to the X direction and the Y direction is defined as the Z direction. explain.

Each lighting device will be described.
The blue light illuminating device 101B, the green light illuminating device 101G, and the red light illuminating device 101R are different from each other only in the color (wavelength range) of emitted light, and have the same device configuration. As an example, the blue light illumination device 101B emits light having a peak wavelength in a wavelength range of approximately 380 nm to 495 nm. The green light illuminating device 101G emits light having a peak wavelength in a wavelength range of approximately 495 nm to 585 nm. The red light illumination device 101R emits light having a peak wavelength in a wavelength range of approximately 585 nm to 720 nm.

  Accordingly, only the blue light illumination device 101B will be described below, and the description of the red light illumination device 101R and the green light illumination device 101G will be omitted.

  FIG. 2 is a perspective view of the blue light illumination device 101B. FIG. 3 is a plan view of the blue light illumination device 101B as viewed in the Z direction. FIG. 4 is a side view of the blue light illuminating device 101B as viewed in the X direction.

  As shown in FIGS. 2 to 4, the blue light illumination device 101 </ b> B includes a light source unit 11, a collimating optical system 12, a light beam compression optical system 13, and a diffusing element 14. The light source unit 11 includes a plurality of light emitting elements 111 and emits a light bundle K composed of a plurality of lights L. The collimating optical system 12 is provided on the optical path of the light beam K emitted from the light source unit 11. The light bundle compression optical system 13 is provided on the optical path of the light bundle K that has passed through the collimating optical system 12. The diffusing element 14 diffuses the light beam K that has passed through the light beam compression optical system 13.

First, the light bundle compression optical system 13 will be described.
The light bundle compression optical system 13 includes a first lens 131, a second lens 132, a third lens 133, and a fourth lens 134 that are arranged in order from the incident side of the light bundle K. The first lens 131 is a spherical lens having a positive power. The second lens 132 is composed of a first anamorphic lens having positive power. The third lens 133 is a second anamorphic lens having negative power. The fourth lens 134 is a spherical lens having negative power.

  The first lens 131 and the fourth lens 134 constitute an afocal optical system that compresses the light bundle K emitted from the collimating optical system 12. The first lens 131 is composed of a plano-convex lens having a convex surface and a flat surface. The fourth lens 134 is constituted by a plano-concave lens having a concave surface and a flat surface.

  The second lens 132 and the third lens 133 constitute a shape adjusting optical system that adjusts the aspect ratio of the light beam K emitted from the collimating optical system 12. The second lens 132 is composed of a first cylindrical lens that is a first anamorphic lens. The first cylindrical lens is composed of a plano-convex lens having a convex surface and a flat surface, and is arranged so that the generatrix 132b faces a direction parallel to the X direction. The third lens 133 is composed of a second cylindrical lens that is a second anamorphic lens. The second cylindrical lens is composed of a plano-concave lens having a concave surface and a flat surface, and is arranged so that the generatrix 133b faces a direction parallel to the X direction.

  The bus 132b of the first cylindrical lens and the bus 133b of the second cylindrical lens are parallel to the longitudinal direction of the image forming region of the blue light liquid crystal light valve 102B corresponding to the blue light illumination device 101B.

  As shown in FIG. 4, the second lens 132 has refractive power only in a plane parallel to the YZ plane orthogonal to the generatrix 132b, so that the light L from the light emitting element 111 is parallel to the YZ plane. Refract in the plane. On the other hand, as shown in FIG. 3, the second lens 132 has no refractive power in a plane parallel to the XY plane parallel to the generatrix 132b. Therefore, the light L is transmitted through the second lens 132 without being refracted in a plane parallel to the XY plane.

  As shown in FIG. 4, the third lens 133 has refractive power only in a plane parallel to the YZ plane orthogonal to the generatrix 133b, so that the light L from the light emitting element 111 is parallel to the YZ plane. Refract in the plane. On the other hand, as shown in FIG. 3, the third lens 133 has no refractive power in a plane parallel to the XY plane parallel to the generatrix 133b. Therefore, the light L is transmitted through the third lens 133 without being refracted in a plane parallel to the XY plane.

  Therefore, the light beam K passes through the light beam compression optical system 13 and is compressed at a higher compression rate in the plane parallel to the YZ plane than in the plane parallel to the XY plane. The distance between the second lens 132 and the third lens 133, the refractive power of the second lens 132, and the refractive power of the third lens 133 are determined by the light beam K transmitted through the light beam compression optical system 13. The aspect ratio of the cross-sectional shape is set to substantially match the aspect ratio of the image forming area.

  Further, since the first lens 131 and the fourth lens 134 constitute an afocal optical system, the telecentricity before and after the light beam compression optical system 13 is maintained.

  As shown in FIG. 2, the light source unit 11 includes a base material 112, a plurality of support members 113, and a plurality of light emitting elements 111 supported by the support members 113. The base material 112 and the support member 113 are made of a metal material having excellent heat dissipation, such as aluminum and copper. The plurality of support members 113 are installed on the first surface 112 a of the base material 112.

  Each support member 113 is a plate-like member and has an upper surface 113a and a lower surface 113b. The planar shapes of the upper surface 113a and the lower surface 113b are substantially rectangular and have long sides in the X direction and short sides in the Y direction. The upper surface 113a is parallel to the XY plane and is a horizontal plane.

  Each of the plurality of light emitting elements 111 is composed of a semiconductor laser. The plurality of light emitting elements 111 are mounted on the upper surface 113a of the support member 113 at a predetermined interval along one direction (X direction). The plurality of support members 113 are fixed to the first surface 112a of the base material 112 at a predetermined interval along one direction (Z direction). In the present embodiment, as an example, the light source unit 11 includes five support members 113 each having five light emitting elements 111 mounted thereon.

  Each light emitting element 111 emits light L composed of one laser beam, and the light source unit 11 emits a light beam K including a plurality of lights L as a whole. The interval between the two lights L adjacent in the X direction and the interval between the two lights L adjacent in the Z direction are substantially the same. Therefore, the cross-sectional shape perpendicular to the central axis of the light beam K is a substantially square shape.

FIG. 5 is a perspective view of the light emitting element 111.
As shown in FIG. 5, the light emitting element 111 has a light emission surface 111 a that emits light L. The light exit surface 111a has a substantially rectangular planar shape having a longitudinal direction W1 and a lateral direction W2 when viewed from the exit direction of the principal ray Lc of the light L from the light exit surface 111a. In FIG. 5, the longitudinal direction W1 is parallel to the X direction, and the short side direction W2 is parallel to the Z direction.

  The light L emitted from the light emitting element 111 is linearly polarized light having a polarization direction parallel to the longitudinal direction W1. The spread of the light L in the short direction W2 is larger than the spread of the light L in the longitudinal direction W1. In the present embodiment, the maximum value (maximum radiation angle) of the spread angle of the light L in the longitudinal direction W1 is 20 °, for example, and the maximum value (maximum radiation angle) of the spread angle in the short direction W2 is 70 °, for example. It is. Therefore, the cross-sectional shape BS of the light L has an elliptical shape with the Z direction (short direction W2) as the major axis direction.

  As shown in FIG. 2, the light beam K emitted from the light source unit 11 enters the collimating optical system 12. The collimating optical system 12 includes a first cylindrical lens array 121 and a second cylindrical lens array 122 arranged in order from the light source unit 11 side.

  As shown in FIG. 4, the first cylindrical lens array 121 includes a plurality of third cylindrical lenses 123. The first cylindrical lens array 121 includes a number of third cylindrical lenses 123 that matches the number of light emitting elements 111 arranged in the Z direction. In the present embodiment, the first cylindrical lens array 121 includes five third cylindrical lenses 123. The plurality of third cylindrical lenses 123 may be integrally formed or may be configured separately.

  As shown in FIG. 3, the second cylindrical lens array 122 includes a plurality of fourth cylindrical lenses 124. The second cylindrical lens array 122 includes a number of fourth cylindrical lenses 124 that matches the number of light emitting elements 111 mounted on each support member 113. In the present embodiment, the second cylindrical lens array 122 includes five fourth cylindrical lenses 124. The plurality of fourth cylindrical lenses 124 may be integrally formed or may be configured separately.

  The fourth cylindrical lens 124 is arranged so that the direction of the bus bar 124 b intersects the upper surface 113 a of the support member 113. As shown in FIG. 2, when the collimating optical system 12 is viewed in the Y direction, the direction of the bus 124b of the fourth cylindrical lens 124 and the direction of the bus 123b of the third cylindrical lens 123 are orthogonal to each other. .

  The third cylindrical lens 123 has a refractive power only in a plane parallel to the YZ plane orthogonal to the generatrix 123b, so that the light L from the light emitting element 111 is collimated in a plane parallel to the YZ plane. . On the other hand, the third cylindrical lens 123 does not have refractive power in a plane parallel to the XY plane parallel to the generatrix 123b. For this reason, the light L passes through the third cylindrical lens 123 without being refracted in a plane parallel to the XY plane.

  Since the fourth cylindrical lens 124 does not have refractive power in a plane parallel to the YZ plane parallel to the generatrix 124b, the light L transmitted through the third cylindrical lens 123 is in a plane parallel to the YZ plane. Passes through the fourth cylindrical lens 124 without being refracted. On the other hand, since the fourth cylindrical lens 124 has a refractive power in a plane parallel to the XY plane orthogonal to the generating line 124b, the light L transmitted through the third cylindrical lens 123 is parallel in the plane parallel to the XY plane. Turn into.

  The distance between the third cylindrical lens 123 and the fourth cylindrical lens 124, the refractive power of the third cylindrical lens 123, and the refractive power of the fourth cylindrical lens 124 are such that the sectional shape of the light L is elliptical. It is set to convert to a substantially circular shape.

  As described above, the light beam K emitted from the light source unit 11 is converted into parallel light by the collimating optical system 12 including the two cylindrical lenses 123 and 124.

  The diffusing element 14 converts the light beam K emitted from the light beam compression optical system 13 into a diffused light beam and emits it toward the liquid crystal light valve 102B for blue light. The uniformity of the illuminance distribution of the light flux K in the image forming region of the blue light liquid crystal light valve 102B is enhanced by the diffusing element 14. As the diffusing element 14, for example, a polished glass plate made of optical glass is used.

  According to the illumination device 101B of the present embodiment, an afocal optical system is configured by the first lens 131 and the fourth lens 134, and the light bundle K from the light source unit 11 has a parallelism by the afocal optical system. The size is reduced while being maintained. The second lens 132 and the third lens 133 constitute a shape adjusting optical system, and the shape adjusting optical system sets the aspect ratio of the light flux K from the light source unit 11 to the aspect of the image forming area of the liquid crystal light valve 102B. It is adjusted so as to substantially match the ratio. As described above, in the light bundle compression optical system 13, the shape adjusting optical system composed of two cylindrical lenses is incorporated in the afocal optical system composed of two spherical lenses, so that the telecentricity can be easily secured. The lighting device 101B can be realized.

In order to verify the effect of the light beam compression optical system 13 of the present embodiment, the inventor performed a simulation of the intensity distribution of the light beam K in the front stage, the rear stage, and the image forming area of the light beam compression optical system 13. The result will be described.
FIG. 6 is a simulation result showing the intensity distribution of the light beam K in the previous stage of the light beam compression optical system 13. FIG. 7 is a simulation result showing the intensity distribution of the light beam K in the latter stage of the light beam compression optical system 13. FIG. 8 is a simulation result showing the intensity distribution of the light flux K in the image forming area. The scales in FIGS. 6, 7 and 8 are different from each other.

  In the preceding stage of the light bundle compression optical system 13, as shown in FIG. 6, the width Wx1 in the X direction and the width Wz1 in the Z direction of the light bundle K are substantially equal, and the arrangement of the plurality of lights L constituting the light bundle K Became a substantially square shape. In addition, as described above, the use of the collimating optical system 12 including two sets of cylindrical lens arrays allows the cross-sectional shape of each light L constituting the light bundle K to be elongated immediately after being emitted from the light emitting element 111. It changed from an ellipse (see FIG. 5) to a circle.

  Since the compression ratio in the Z direction of the light beam compression optical system 13 is larger than the compression ratio in the X direction, in the subsequent stage of the light beam compression optical system 13, as shown in FIG. Is smaller than the width Wx2 in the X direction, and the arrangement of the plurality of lights L constituting the light bundle K is rectangular. Further, the cross-sectional shape of each light L constituting the light bundle K is an ellipse having a longitudinal direction in the X direction. The shape (aspect ratio) and size of the cross section of the light beam K are approximately the same as the shape and size of the image forming area H, respectively.

  When the light beam K having the intensity distribution shown in FIG. 7 is transmitted through the diffusing element 14, the intensity distribution in the image forming region H becomes substantially uniform as shown in FIG.

  Thus, according to the light beam compression optical system 13 of the present embodiment, it has been found that the size and aspect ratio of the light beam K from the light source unit 11 can be optimized.

  In the illumination device 101B of the present embodiment, the first anamorphic lens that constitutes the second lens 132 is constituted by the first cylindrical lens, and the second anamorphic lens that constitutes the third lens 133 is the first. Since it is comprised from 2 cylindrical lenses, the cost of an illuminating device can be reduced.

  In the illumination device 101B of the present embodiment, the collimating optical system 12 includes a third cylindrical lens and a fourth cylindrical lens, and therefore a collimating optical system including a plurality of convex lenses (spherical lenses) is used. As shown in FIG. 7, the interval between the plurality of lights L after the size of the light beam K is reduced is smaller than the case where the light beams K are present. Thereby, the illuminance uniformity of the light beam K can be improved.

  The above effects can also be obtained in the lighting devices 101G and 101R.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The configuration of the projector of the second embodiment is substantially the same as that of the first embodiment, but the configuration of the illumination device is different from that of the first embodiment. Therefore, description of the whole projector is omitted, and only different parts will be described.
FIG. 9 is a perspective view of the blue light illumination device 201B of the present embodiment.
In FIG. 9, the same components as those used in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

As shown in FIG. 9, the blue light illumination device 201 </ b> B includes a light source unit 11, a collimating optical system 16, a light bundle compression optical system 13, and a diffusing element 14. The collimating optical system 16 includes a plurality of spherical convex lenses 161 equal in number to the plurality of light emitting elements 111. Each of the plurality of spherical convex lenses 161 has a spherical convex surface and a flat surface, and is provided corresponding to each of the plurality of light emitting elements 111. The longitudinal direction of the light emission region of the semiconductor laser that constitutes the light emitting element 111 is parallel to the generatrix of the first cylindrical lens that constitutes the second lens 132 and the generatrix of the second cylindrical lens that constitutes the third lens 133. It is.
Other configurations of the blue light illumination device 201B are the same as those in the first embodiment.

  Also in this embodiment, the same effect as 1st Embodiment that the small illuminating device which can ensure telecentricity easily is realizable is acquired.

In order to verify the effect of the light beam compression optical system 13 of the present embodiment, the inventor performed a simulation of the intensity distribution of the light beam K in the front stage, the rear stage, and the image forming area of the light beam compression optical system 13. The result will be described.
FIG. 10 is a simulation result showing the intensity distribution of the light beam K in the previous stage of the light beam compression optical system 13. FIG. 11 is a simulation result showing the intensity distribution of the light beam K in the latter stage of the light beam compression optical system 13. FIG. 12 is a simulation result showing the intensity distribution of the light flux K in the image forming area. The scales in FIGS. 10, 11 and 12 are different from each other.

  In the preceding stage of the light bundle compression optical system 13, as shown in FIG. 10, the width Wx3 in the X direction and the width Wz3 in the Z direction of the light bundle K are substantially equal, and the arrangement of the plurality of lights L constituting the light bundle K Became a substantially square shape. Further, unlike the first embodiment, since the collimating optical system 16 including a plurality of spherical convex lenses 161 is used, the cross-sectional shape of each light L constituting the light bundle K is just after being emitted from the light emitting element 111. Similarly, it is an elongated ellipse (see FIG. 5).

  In the subsequent stage of the light bundle compression optical system 13, as shown in FIG. 11, the width Wz4 in the Z direction of the light bundle K is smaller than the width Wx4 in the X direction, and the arrangement of the plurality of lights L constituting the light bundle K is as follows. It became a rectangular shape. Further, the cross-sectional shape of each light L constituting the light bundle K is an ellipse, but is shorter than the cross-sectional shape of each light L in the previous stage of the light bundle compression optical system 13 shown in FIG. The ratio of the length in the major axis direction to the length in the axial direction (aspect ratio) has decreased. The shape (aspect ratio) and size of the cross section of the light beam K are approximately the same as the shape and size of the image forming area H, respectively.

  When the light beam K having the intensity distribution shown in FIG. 11 is transmitted through the diffusing element 14, the intensity distribution in the image forming region becomes substantially uniform as shown in FIG.

  Thus, according to the light beam compression optical system 13 of the present embodiment, it has been found that the size and aspect ratio of the light beam from the light source unit 11 can be optimized.

  Further, in the illumination device of the present embodiment, the longitudinal direction of the light emission region of the semiconductor laser is parallel to the generatrix of the first cylindrical lens and the generatrix of the second cylindrical lens. Is smaller than the vertical axis of the first cylindrical lens and the second cylindrical lens, the aspect ratio of the ellipse, which is the cross-sectional shape of each light L, becomes smaller, and the size of the light bundle is reduced. The interval between the plurality of lights L is reduced. Thereby, the uniformity of the illuminance of the light beam K can be further increased.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the light bundle compression optical system includes both the first anamorphic lens that constitutes the second lens and the second anamorphic lens that constitutes the third lens, and these cylindrical lenses. In the plane parallel to the generatrix (XY plane), the first anamorphic lens having the refractive power in both the XY plane and the YZ plane and the second are replaced with this configuration. The anamorphic lens may be used. In this case, it is desirable that the refractive power in the YZ plane is larger than the refractive power in the XY plane. According to this configuration, the power shortage of the first lens and the fourth lens can be compensated by the first anamorphic lens and the second anamorphic lens.

  In the above embodiment, the light beam compression optical system uses a spherical lens (concave lens) having negative power as the fourth lens, but a spherical lens (convex lens) having positive power is used. May be.

  In addition, the number, arrangement, shape, material, size, and the like of each component of the light source unit, the illumination device, and the projector exemplified in the above embodiment can be changed as appropriate.

  In the above embodiment, a projector including three light modulation devices has been illustrated, but the present invention can also be applied to a projector that displays a color image with one light modulation device. A digital mirror device may be used as the light modulation device.

  Moreover, in the said embodiment, although the example which applies the illuminating device by this invention to a projector was shown, it is not restricted to this. The lighting device according to the present invention can also be applied to lighting fixtures such as automobile headlights.

  DESCRIPTION OF SYMBOLS 11 ... Light source part, 12, 16 ... Collimating optical system, 13 ... Light bundle compression optical system, 14 ... Diffusing element, 100 ... Projector, 101B ... Illuminating device for blue light (illuminating device), 101G ... Illuminating device for green light ( Illumination device), 101R ... red light illumination device (illumination device), 102B ... blue light liquid crystal light valve (light modulation device), 102G ... green light liquid crystal light valve (light modulation device), 102R ... red light liquid crystal Light valve (light modulation device), 104 ... projection optical system, 111 ... light emitting element, 131 ... first lens, 132 ... second lens, 133 ... third lens, 134 ... fourth lens, K ... light beam Bundle, L ... light.

Claims (7)

A light source unit that includes a plurality of light emitting elements and emits a light bundle composed of a plurality of lights;
A collimating optical system provided on an optical path of the light beam emitted from the light source unit;
A light bundle compression optical system provided on an optical path of the light bundle that has passed through the collimating optical system;
With
The light bundle compression optical system includes a first lens, a second lens, a third lens, and a fourth lens arranged in order from the incident side of the light bundle,
The first lens comprises a spherical lens having positive power;
The second lens comprises a first anamorphic lens having positive power;
The third lens comprises a second anamorphic lens having negative power;
The illumination device, wherein the fourth lens is a spherical lens. The first anamorphic lens comprises a first cylindrical lens;
The lighting device according to claim 1, wherein the second anamorphic lens includes a second cylindrical lens. Each of the plurality of light emitting elements comprises a semiconductor laser,
The collimating optical system includes a third cylindrical lens, and a fourth cylindrical lens provided at a subsequent stage of the third cylindrical lens,
The lighting device according to claim 1, wherein a bus line of the third cylindrical lens and a bus bar of the fourth cylindrical lens are orthogonal to each other. Each of the plurality of light emitting elements comprises a semiconductor laser,
The collimating optical system includes a plurality of convex lenses,
3. The illumination device according to claim 2, wherein a longitudinal direction of a light emission region of the semiconductor laser is parallel to a generatrix of the first cylindrical lens and a generatrix of the second cylindrical lens.   The illumination device according to any one of claims 1 to 4, further comprising a diffusing element that diffuses the light beam that has passed through the light beam compression optical system. A lighting device according to any one of claims 1 to 5,
A light modulation device that forms image light by modulating the light flux from the illumination device according to image information;
A projection optical system that projects the image light. The light modulation device includes an image forming region having a longitudinal direction,
The first anamorphic lens comprises a first cylindrical lens;
The second anamorphic lens comprises a second cylindrical lens;
The projector according to claim 6, wherein a generating line of the first cylindrical lens and a generating line of the second cylindrical lens are parallel to the longitudinal direction.