JP2019061082A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device for solving various problems caused by an increase in excitation light. SOLUTION: A light source device 2 emits a first light emitting device 711B that emits a first light LB1 in a first wavelength region and a second light LR2 that emits a second light LR2 in a first polarization direction in a second wavelength region. The light source unit 70 having the light emitting device 711R of the above, and a first light that converts the first light into light including a third light LB3 in the first polarization direction and a fourth light LB4 in the second polarization direction. A wavelength conversion element 27 including a retardation element 46 and a phosphor layer 34 excited by a fourth light to generate a fifth light LG 5 in the third wavelength region, and a sixth light diffused sixth. The diffuser 301 that generates the light LR6 and the seventh light LB7 in which the third light is diffused, and the fourth light is separated from the second light and the third light and guided to the wavelength conversion element. , The second light and the third light are guided to the diffusing element, and the fifth light from the wavelength conversion element and the sixth light and the seventh light from the diffusing element are combined to generate illumination light. The separation element 50 and the like are provided. [Selection diagram] Fig. 2

Description

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

  As a light source device used for a projector, a light source device using fluorescence emitted from a phosphor when the excitation light emitted from a light emitting element such as a semiconductor laser is irradiated to the phosphor has been proposed.

  For example, in Patent Document 1 below, a semiconductor laser emitting blue light, a first retardation plate on which blue light is incident, and light from the first retardation plate are separated into two light beams having different polarization states. A lighting device comprising a first polarization separation element, a wavelength conversion element including a phosphor for converting a part of blue light into yellow light, and a diffusion element for diffusing another part of blue light is disclosed ing. In Patent Document 1, according to this illumination device, the ratio of yellow light from the wavelength conversion element to blue light from the diffusion element is adjusted by rotating the direction of the optical axis of the first retardation plate. It can be said that the white balance can be adjusted.

  Further, in Patent Document 2 below, a semiconductor laser emitting blue light, a semiconductor laser emitting red light, a polarization separation element, a phosphor layer absorbing blue light to generate green light, and blue light And a reflector configured to reflect red light. According to Patent Document 2, in this lighting device, when blue light and red light are incident on the phosphor layer through the polarization separation element, green light emitted from the phosphor using the blue light as excitation light and a reflection portion It is described that the blue light and the red light reflected by are combined to generate white light.

JP, 2015-106130, A JP, 2014-199401, A

However, the illumination devices of Patent Documents 1 and 2 have the following problems.
The wavelength conversion element described in Patent Document 1 includes a phosphor that converts blue light to yellow light, that is, a phosphor that converts blue light to light including a green light component and a red light component. Therefore, it is necessary to excite both the phosphor that emits the green light component and the phosphor that emits the red light component, and it is necessary to irradiate a large amount of excitation light to the phosphor. As a result, problems such as increase in light density and decrease in conversion efficiency of the phosphor, temperature quenching, difficulty in adjusting the color temperature, and easy damage to the phosphor arise.

  Moreover, in the illumination device described in Patent Document 2, unlike the illumination device of Patent Document 1, a phosphor that generates green light is used. However, since the fluorescent material is irradiated with blue light and red light, the light density and temperature of the fluorescent material are increased, and the same problems as in Patent Document 1 occur.

  One aspect of the present invention is made in order to solve the above-mentioned subject, and it is providing the light source device which can eliminate the various fault accompanying the increase in the excitation light irradiated to fluorescent substance. As one of the goals. Another object of the present invention is to provide a projector provided with the above light source device.

  In order to achieve the above object, a light source device according to one aspect of the present invention comprises: a first light emitting device for emitting a first light in a first wavelength range; and a second wavelength different from the first wavelength range A light source unit having a second light emitting device for emitting a second light in a first polarization direction of the region, and provided on an optical path of the first light and the second light, A first retardation element for converting the light into the light including the third light of the first polarization direction and the fourth light of the second polarization direction different from the first polarization direction, and the fourth light A wavelength conversion element that generates a fifth light of a third wavelength range that includes a phosphor excited by the first wavelength range and the second wavelength range, and the second light and the third light And a diffusion element that generates a sixth light into which the second light is diffused and a seventh light into which the third light is diffused, and The fourth light is separated from the second light and the third light among the second light, the third light, and the fourth light emitted from the phase difference element, and the wavelength conversion is performed. The light is guided to the element, the second light and the third light are guided to the diffusion element, and the fifth light emitted from the wavelength conversion element and the sixth light emitted from the diffusion element And a polarization separation element that generates illumination light by combining the seventh light.

  In the light source device according to one aspect of the present invention, the first light of the first wavelength range from the first light emitting device is subjected to the third light of the first polarization direction and the second polarization direction by the first retardation element. And the fourth light is guided to the wavelength conversion element by the polarization separation element. In the wavelength conversion element, the phosphor is excited by the fourth light to generate fifth light in the third wavelength range. On the other hand, the second light from the second light emitting device and the third light converted by the first retardation element are guided by the polarization separation element to the diffusion element, and these lights are diffused to form the sixth light source. Light and seventh light are generated respectively. The fifth light emitted from the wavelength conversion element and the sixth light and the seventh light emitted from the diffusion element are combined by the polarization separation element to become illumination light.

  As described above, in the light source device according to one aspect of the present invention, the excitation light, in which the fourth light in the first wavelength range out of the first to third wavelength ranges that is the wavelength range of the illumination light excites the phosphor As a result, fifth light in the third wavelength range is generated, and second light in the second wavelength range and third light in the first wavelength range enter the diffusion element. In other words, in the light source device according to one aspect of the present invention, a part of the first color light is made to be incident on the phosphor to generate the third color light, and the other light source of the first color light is generated. A part and the second color light are diffused by the diffusion element. As a result, in the light source device according to one aspect of the present invention, the amount of excitation light can be reduced as compared with the illumination devices of Patent Documents 1 and 2, and various problems associated with the increase of the excitation light can be eliminated. At the same time, high intensity light can be obtained.

  In the light source device according to one aspect of the present invention, the light source unit includes a plurality of first light emitting devices, a plurality of second light emitting devices, a plurality of first light emitting devices, and a plurality of second light emitting devices. A plurality of light emitting devices, and the plurality of first light emitting devices and the plurality of second light emitting devices are disposed in rotational symmetry with respect to a central axis of the light source unit. It is also good.

  According to this configuration, the incident angles when the plurality of third lights generated from the plurality of first lights enter the diffusion element, and the incident angles when the plurality of second lights enter the diffusion element And can be made approximately equal. Thereby, it is possible to suppress color unevenness regarding the first wavelength range and the second wavelength range.

  In the light source device according to one aspect of the present invention, when the first light and the second light having different wavelength ranges are incident, the first retardation element is for the first light. Therefore, it may be configured by a narrow band retardation plate which selectively gives a phase difference.

  According to this configuration, it is possible to arrange the first retardation element over the optical path of the first light and the optical path of the second light. Therefore, it is not necessary to process the shape of the first retardation element in accordance with the optical path of each light, or to arrange the first retardation element only on the optical path of the first light, and thus the first position can be obtained. The configuration of the phase difference element can be simplified.

  In the light source device according to one aspect of the present invention, the first retardation element is disposed on the optical path of the first light, and is not disposed on the optical path of the second light. It may be composed of a plate.

  According to this configuration, since the second light does not pass through the first retardation element, a retardation plate having no wavelength dependency can be used as the first retardation element. The heat resistance of the first retardation element can be secured by using, for example, quartz as a material of the retardation plate.

  In the light source device according to one aspect of the present invention, the light source unit includes a first light source unit including a plurality of the first light emitting devices, a second light source unit including a plurality of the second light emitting devices, A dichroic mirror may be provided to combine the plurality of first lights from one light source unit and the plurality of second lights from the second light source unit.

  According to this configuration, it is possible to arrange the first light source unit including the plurality of first light emitting devices and the second light source unit including the plurality of second light emitting devices at separated positions. You can increase the freedom of placement. Furthermore, according to this configuration, since the first retardation element can be disposed on the optical path of the first light between the first light source unit and the dichroic mirror, wavelength dependency as the first retardation element can be obtained. It is possible to use a retardation plate which is not provided. The heat resistance of the first retardation element can be secured by using, for example, quartz as a material of the retardation plate.

  The light source device according to one aspect of the present invention may further include a drive unit that rotates the direction of the optical axis of the first retardation element, and the drive unit rotates the direction of the optical axis. The ratio of the light amount of the third light after emitting the first retardation element to the light amount of the fourth light may be adjusted.

  According to this configuration, the seventh light emitted from the diffusion element is adjusted by adjusting the ratio between the light amount of the third light incident on the diffusion element and the light amount of the fourth light incident on the wavelength conversion element. The ratio between the light amount and the light amount of the fifth light emitted from the wavelength conversion element can be adjusted. Thereby, it is possible to suppress color unevenness caused by the color in the first wavelength range and the color in the third wavelength range.

  A light source device according to one aspect of the present invention includes a light amount detection unit that detects a light amount of the fifth light, a light amount of the sixth light, and a light amount of the seventh light that constitute the illumination light; A control unit configured to at least control the control unit and the second light emitting device, and the control unit controls the rotation of the first retardation element based on the detection result of the light amount detection unit. At least one of the angle and the light amount of the second light emitted from the second light emitting device may be adjusted.

  According to this configuration, the control unit adjusts the rotation angle of the first phase difference element based on the detection result of the light amount detection unit, thereby converting the light amount of the seventh light emitted from the diffusion element and the wavelength conversion. It is possible to adjust the ratio to the light amount of the fifth light emitted from the element, and further adjust the light amount of the second light from the second light-emitting device to obtain the sixth light emitted from the diffusion element. The amount of light can be adjusted. Thereby, it is possible to suppress color unevenness caused by the color of the first wavelength range, the color of the second wavelength range, and the color of the third wavelength range.

  The light source device according to one aspect of the present invention reflects the second light and the third light incident from the first surface of the diffusion element to generate the sixth light and the seventh light. The light emitting device is provided on the optical path of the second light and the third light between the polarization separation element and the diffusion element, and the reflection part to be emitted from the first surface, and the first wavelength band and the second light And a second phase difference element capable of giving a phase difference to both light of the wavelength range.

  According to this configuration, a reflective diffusion element can be used, so the configuration of the optical system of the light source device can be simplified.

  In the light source device according to one aspect of the present invention, the first light emitting device is composed of a solid light source emitting blue light, and the second light emitting device is composed of a solid light source emitting red light, The phosphor may be composed of a phosphor that emits green light.

  In general, a phosphor emitting green light has higher conversion efficiency than a phosphor emitting red light. In addition, a solid-state light source that emits red light has higher luminous efficiency than a solid-state light source that emits green light. Therefore, according to the above configuration, it is possible to realize a highly efficient light source device capable of emitting white light.

  A projector according to one aspect of the present invention includes a light source device according to one aspect of the present invention, a light modulation device that forms image light by modulating light from the light source device according to image information, and the image light And a projection optical system for projecting light.

  According to this configuration, a projector excellent in display quality can be realized.

It is a schematic block diagram of the projector of 1st Embodiment. It is a schematic block diagram of the light source device of 1st Embodiment. It is a perspective view of a light source part. It is a front view of the light source part seen from the X direction. It is a graph which shows the spectral characteristic of a polarization separation element. It is a front view of the light source part which shows the modification of a 1st phase difference plate. It is a schematic block diagram of the light source device of 2nd Embodiment. It is a schematic block diagram of the light source device of 3rd Embodiment.

First Embodiment
Hereinafter, a first embodiment of the present invention will be described using FIGS. 1 to 8.
The projector of the present embodiment is an example of a liquid crystal projector provided with a light source device using a semiconductor laser.
In addition, in order to make each component intelligible in the following each drawing, the reduced scale of a dimension may be changed and shown with components.

  The projector 1 of the present embodiment is a projection type image display device that displays a color image on the screen SCR. The projector 1 uses three light modulation devices corresponding to each color light of red light LR, green light LG, and blue light LB. The projector 1 uses, as a light emitting element of the light source device, a semiconductor laser capable of obtaining light with high brightness and high output.

FIG. 1 is a schematic configuration diagram of a projector 1 according to the present embodiment.
As shown in FIG. 1, the projector 1 includes a light source device 2, a color separation light guide optical system 3, a light modulation device 4R for red light, a light modulation device 4G for green light, a light modulation device 4B for blue light, a light combining optical system 5 and a projection optical system 6 are provided.

  In the present embodiment, the light source device 2 emits white illumination light WL including red light LR, green light LG, and blue light LB. The detailed configuration of the light source device 2 will be described later.

  The color separation light guide optical system 3 includes a dichroic mirror 7a, a dichroic mirror 7b, a reflection mirror 8a, a reflection mirror 8b, a reflection mirror 8c, a relay lens 9a, and a relay lens 9b. The color separation light guide optical system 3 separates the illumination light WL from the light source device 2 into red light LR, green light LG, and blue light LB, while supporting red light LR, green light LG, and blue light LB respectively. It guides to the light modulation device 4R for red light, the light modulation device 4G for green light, and the light modulation device 4B for blue light.

  A field lens 10R is disposed between the color separation light guide optical system 3 and the red light light modulation device 4R. A field lens 10G is disposed between the color separation light guide optical system 3 and the light modulation device 4G for green light. A field lens 10B is disposed between the color separation light guide optical system 3 and the blue light light modulation device 4B.

  The dichroic mirror 7a transmits the red light LR and reflects the green light LG and the blue light LB. The dichroic mirror 7b reflects the green light LG and transmits the blue light LB. The reflection mirror 8a reflects the red light LR. The reflection mirror 8 b and the reflection mirror 8 c reflect the blue light LB.

  Each of the red light light modulation device 4R, the green light light modulation device 4G, and the blue light light modulation device 4B is configured of a liquid crystal panel that modulates incident color light according to image information to form an image. ing.

  Although illustration is omitted, on the incident side between the field lens 10R, the field lens 10G, the field lens 10B and the red light light modulation device 4R, the green light light modulation device 4G, and the blue light light modulation device 4B, respectively. A polarizer is disposed. Between the light modulation device 4R for red light, the light modulation device 4G for green light, the light modulation device 4B for blue light, and the light combining optical system 5, an emission side polarization plate is disposed.

  The light combining optical system 5 is configured of a cross dichroic prism. The light combining optical system 5 combines the image light emitted from each of the red light light modulation device 4R, the green light light modulation device 4G, and the blue light light modulation device 4B to form a color image. The cross dichroic prism has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is provided at a substantially X-shaped interface in which right-angle prisms are bonded together.

  The color image emitted from the light combining optical system 5 is enlarged and projected onto the screen SCR by the projection optical system 6.

FIG. 2 is a schematic block diagram of the light source device 2.
In the following description, as the coordinate axis, the direction in which the illumination light WL is emitted from the light source device 2 is the Y direction, the direction in which the blue light LB and the red light LR are emitted from the light source unit is the X direction, and the X and Y directions And the orthogonal coordinate system in which the direction from the front to the back of the paper surface is the Z direction.

  As shown in FIG. 2, the light source device 2 includes a light source unit 70, a first retardation plate 46 (first retardation element), a motor 47 (drive unit), a homogenizer optical system 24, and polarization separation. An element 50, a first pickup optical system 26, a wavelength conversion element 27, a second retardation plate 28 (second retardation element), a second pickup optical system 29, a diffuser 30, and An integrator optical system 31, a polarization conversion element 32, a superposition optical system 33, a light amount monitor mirror 42, a light amount detection unit 43, and a control unit 44 are provided.

  Among the components described above, the light source unit 70, the first retardation plate 46, the homogenizer optical system 24, the polarization separation element 50, the second retardation plate 28, and the second pickup optical system 29 The diffusers 30 are sequentially arranged on the optical axis ax1. On the other hand, the wavelength conversion element 27, the first pickup optical system 26, the polarization separation element 50, the integrator optical system 31, the polarization conversion element 32, and the superposition optical system 33 are sequentially arranged on the optical axis ax2. It is arranged. The optical axis ax1 and the optical axis ax2 are in the same plane and in a positional relationship orthogonal to each other.

FIG. 3 is a perspective view of the light source unit 70. In FIG. 3, in order to make the drawing easy to see, illustration of pedestals of some semiconductor lasers is omitted.
FIG. 4 is a front view of the light source unit 70 as viewed from the X-axis direction.
As shown in FIGS. 3 and 4, the light source unit 70 includes a plurality of blue semiconductor lasers 711 B (first light emitting devices), a plurality of red semiconductor lasers 711 R (second light emitting devices), and a plurality of blue semiconductor lasers And a support member 712 for supporting the plurality of red semiconductor lasers 711R. In the present embodiment, the light source unit 70 includes three blue semiconductor lasers 711B and four red semiconductor lasers 711R. However, the number of blue semiconductor lasers 711 B and red semiconductor lasers 711 R can be changed as appropriate.

  Each of the three blue semiconductor lasers 711B emits, for example, blue light LB1 (first light in a first wavelength range) having a peak wavelength of 460 to 480 nm. That is, the blue semiconductor laser 711B is configured of a solid light source that emits blue light LB1. Each of the four red semiconductor lasers 711R emits P-polarized red light LR2 (second light in the first polarization direction in the second wavelength range) having a peak wavelength of, for example, 610 to 680 nm. That is, the red semiconductor laser 711R is configured of a solid light source that emits red light LR2. In the present specification, descriptions of polarization directions such as P polarization and S polarization are referred to as polarization directions with respect to the polarization separation element 50 unless otherwise specified.

  In the following description, the three blue lights LB1 emitted from the three blue semiconductor lasers 711B are collectively referred to as a blue light LB1. Similarly, the four red lights LR2 emitted from the four red semiconductor lasers 711R are collectively referred to as a red light LR2. That is, the light source unit 70 emits the blue light LB1 and the red light LR2.

  The blue semiconductor laser 711B and the red semiconductor laser 711R are configured of CAN package type semiconductor lasers. The package 716 is common to both of the semiconductor lasers 711 B and 711 R, and includes a pedestal 713 and a can 714. The blue semiconductor laser 711 B includes one blue semiconductor laser chip 715 B housed in a package 716. The red semiconductor laser 711R includes one red semiconductor laser chip 715R housed in a package 716. In both of the blue semiconductor laser 711B and the red semiconductor laser 711R, a collimating lens 788 (see FIG. 3) is mounted on the light emitting side of the package 716.

  The support member 712 is a disc-shaped member, and supports the plurality of blue semiconductor lasers 711B and the plurality of red semiconductor lasers 711R. Although the material of the support member 712 is not particularly limited, for example, a metal having high thermal conductivity is desirable.

  As shown in FIG. 4, when viewed from the X direction (the light emission direction), the three blue semiconductor lasers 711B and the three red semiconductor lasers 711R surround one central red semiconductor laser 711R. Is located in Further, the three blue semiconductor lasers 711 B and the three red semiconductor lasers 711 R on the outer circumferential side are alternately provided along the circumferential direction of the support member 712. One blue semiconductor laser 711 B is in contact with the adjacent red semiconductor laser 711 R. One red semiconductor laser 711R is in contact with the blue semiconductor lasers 711B on both sides. The blue semiconductor lasers 711B and the red semiconductor lasers 711R on the outer periphery are in contact with the central red semiconductor laser 711R. That is, a total of seven semiconductor lasers 711 B and 711 R are arranged in the closest packing.

  Thus, the three blue semiconductor lasers 711 B are disposed substantially rotationally symmetric about the central axis CB of the light source unit 70. Further, the four red semiconductor lasers 711R are disposed substantially rotationally symmetric about the central axis CB of the light source unit 70. Thus, the central axis of the blue light LB1 and the central axis of the red light LR2 coincide with the central axis CB of the light source unit 70. Thereby, color unevenness of the image displayed on the screen SCR is reduced. This effect will be described in detail later. In the present specification, the description “substantially rotational symmetry” includes not only a completely rotationally symmetrical arrangement but also an arrangement capable of reducing color unevenness to an acceptable degree.

  As shown in FIG. 4, the red semiconductor laser 711R is disposed in the direction in which the longitudinal direction W1 of the light emitting region 715Ra of the red semiconductor laser chip 715R is parallel to the Z axis. The red semiconductor laser chip 715R emits linearly polarized light in which the short direction W2 of the light emitting region 715Ra is the polarization direction. That is, the red semiconductor laser 711R emits linearly polarized light whose polarization direction is the Y direction, that is, P polarized light. Thus, the red light LR2 can pass through the polarization separation element 50 in the rear stage.

  In addition, the blue semiconductor laser 711B is disposed in the same direction as the longitudinal direction W1 of the light emitting region 715Ba of the blue semiconductor laser chip 715B in parallel to the Z axis, similarly to the red semiconductor laser 711R. However, the blue semiconductor laser chip 715B emits linearly polarized light in which the longitudinal direction W1 of the light emitting region 715Ba is the polarization direction due to the difference in oscillation mode from that of the red semiconductor laser chip 715R. That is, the blue semiconductor laser 711B emits linearly polarized light whose polarization direction is the Z direction, that is, S polarized light.

  The red semiconductor laser 711R must emit p-polarized light so that the red light LR2 can pass through the polarization separation element 50. On the other hand, the blue semiconductor laser 711B emits the P-polarized light because the blue light LB1 is converted into the light including the P-polarized light and the S-polarized light by the first retardation plate 46 in the latter stage. Alternatively, S-polarized light may be emitted, or light in which P-polarized light and S-polarized light are mixed may be emitted. Therefore, in the example of FIG. 4, the longitudinal direction W1 of the light emitting area 715Ba of the blue semiconductor laser chip 715B faces the Z axis, but unlike the red semiconductor laser chip 715R, the longitudinal direction of the light emitting area 715Ba of the blue semiconductor laser chip 715B W1 may point in any direction.

  As shown in FIG. 2, the first retardation plate 46 is provided on the optical path of the blue light LB1 and the red light LR2 between the light source unit 70 and the homogenizer optical system 24. As shown in FIG. 4, the planar shape of the first retardation plate 46 (shaded part) viewed from the X direction is annular, and three blue semiconductor lasers 711 B on the outer peripheral side of the light source unit 70. And the optical paths of the three red semiconductor lasers 711R, and not the optical paths of the central red semiconductor laser 711R. Therefore, the blue light LB1 emitted from the blue semiconductor laser 711B on the outer peripheral side and the red light LR2 emitted from the red semiconductor laser 711R enter the first retardation plate 46. The planar shape of the first retardation plate 46 may be circular or may overlap with the optical path of the central red semiconductor laser 711R.

  The first retardation plate 46 is configured of a narrow band retardation plate that selectively gives a phase difference to the blue light LB1 when the blue light LB1 and the red light LR2 having different wavelength ranges are incident. ing. Specifically, the first retardation plate 46 does not function as a wave plate for the red light LR2, and functions as a 1⁄2 wavelength plate only for the blue light LB1 with Color Select (registered trademark) It is composed of a so-called narrow band retarder. This type of narrow band retardation plate is made of a stretched film made of resin.

  The first retardation plate 46 is rotatably provided in the plane on which the blue light LB1 and the red light LR2 are incident. The first retardation plate 46 is disposed such that the optical axis of the first retardation plate 46 intersects with the polarization axis of the blue light LB1. The optical axis of the first retardation plate 46 may be either the fast axis or the slow axis of the first retardation plate 46.

  Therefore, when the blue light LB1 of S polarization and the red light LR2 of P polarization are incident on the first retardation plate 46, the red light LR2 of P polarization is not changed in polarization direction with respect to the red light LR2. The light is emitted from the first retardation plate 46. On the other hand, for the blue light LB1, the blue light LB1 includes the blue light LB3 of P-polarization (third light of the first polarization direction) and the blue light LB4 of S-polarization (fourth light of the second polarization direction). The light is converted into light and emitted from the first retardation plate 46.

  That is, since the polarization axis of the blue light LB1 crosses the optical axis of the first retardation plate 46, the blue light LB1 includes S-polarization and P-polarization by transmitting the first retardation plate 46. Light is generated. As a result, the blue light LB1 transmitted through the first retardation plate 46 becomes light in which the blue light LB3 of P polarization and the blue light LB4 of S polarization are mixed at a predetermined ratio. The red light LR2 from the red semiconductor laser 711R at the center of the light source unit 70 does not enter the first retardation plate 46, and therefore remains as P-polarization.

  A motor 47 for rotating the first retardation plate 46 is connected to the first retardation plate 46. The motor 47 rotates the direction of the optical axis of the first retardation plate 46 in response to a signal from the control unit 44 described later.

  The homogenizer optical system 24 is provided on the optical path of the blue light LB 3 and LB 4 and the red light LR 2 between the first retardation plate 46 and the polarization separation element 50. The homogenizer optical system 24 converts the light intensity distribution of the blue light LB3 and LB4 and the red light LR2 into a uniform light intensity distribution called, for example, a top hat type distribution on the phosphor layer 34 or the diffusion plate 301. The homogenizer optical system 24 comprises, for example, a multi-lens array 24a and a multi-lens array 24b.

  The blue light LB 3 and LB 4 and the red light LR 2 emitted from the homogenizer optical system 24 enter the polarization separation element 50. The polarization separation element 50 is disposed at an angle of 45 ° with respect to both the optical axis ax1 and the optical axis ax2. The polarization separation element 50 has a polarization separation function of separating S-polarized light and P-polarized light with respect to the blue light LB3 and LB4 and the red light LR2. Specifically, since the polarization separation element 50 has the characteristic of transmitting p-polarized light and reflecting s-polarized light, it transmits the red light LR2 and the blue light LB3 and reflects the blue light LB4.

  In addition, the polarization separation element 50 has a color separation function of transmitting green light LG5 different in wavelength band from the blue light LB3 and LB4 and the red light LR2 regardless of the polarization state.

FIG. 5 is a graph showing an example of the spectral characteristics of the polarization separation element 50 of the present embodiment. In FIG. 5, the horizontal axis is the wavelength (nm), and the vertical axis is the transmittance (%). The graph of the code GP shows the characteristics of P polarization, and the graph of the code GS shows the characteristics of S polarization.
For example, 450 to 460 nm as a blue wavelength, 500 to 600 nm as a green wavelength, and 635 to 645 nm as a red wavelength.
As shown in FIG. 5, for P-polarized light, the transmittance is 98% or more in the wavelength 450 to 460 nm region, and the transmittance is 98% or more in the wavelength 500 to 600 nm region, the wavelength 635 to 645 nm region Shows a transmittance of 98% or more. For S-polarized light, the transmittance is less than 2% in the wavelength 450-460 nm region, the transmittance is 98% or more in the wavelength 500-600 nm region, and the transmittance is less than 2% in the wavelength 635-645 nm region Indicates As described above, the polarization separation element 50 transmits P polarized light for blue light and red light, reflects S polarized light, and transmits green light regardless of the polarization state.

  Therefore, as shown in FIG. 2, the polarization separation element 50 generates blue light LB4 from red light LR2 and blue light LB3 among red light LR2 and blue light LB3 and LB4 emitted from the first retardation plate 46. Are separated, the blue light LB4 is guided to the wavelength conversion element 27, the red light LR2 and the blue light LB3 are guided to the diffusion device 30, and the green light LG5 emitted from the wavelength conversion element 27 is emitted from the diffusion device 30 The red light LR6 and the blue light LB7 are combined to generate a white illumination light WL.

  The blue light LB 4 reflected by the polarization separation element 50 is incident on the first pickup optical system 26. The first pickup optical system 26 condenses the blue light LB4 toward the phosphor layer 34 of the wavelength conversion element 27. The first pickup optical system 26 includes a pickup lens 26a and a pickup lens 26b.

  The blue light LB 4 emitted from the first pickup optical system 26 enters the wavelength conversion element 27. The wavelength conversion element 27 includes a phosphor layer 34 including a phosphor excited by the blue light LB4, and a substrate 35 supporting the phosphor layer 34. When the blue light LB4 is incident on the phosphor layer 34, the phosphor contained in the phosphor layer 34 is excited, and the green light LG5 having a wavelength range different from that of the blue light LB4 and the red light LR2 (fifth wavelength region Light) is generated. The wavelength range of the green light LG5 is, for example, 500 to 590 nm. That is, the phosphor is composed of a phosphor that emits green light LG5.

  In the wavelength conversion element 27, the phosphor layer 34 is provided between the side surface of the phosphor layer 34 and the substrate 35 in a state where the surface opposite to the side on which the blue light LB4 is incident is in contact with the substrate 35. It is fixed to the substrate 35 by an adhesive 36. A heat sink 38 for dissipating the heat of the phosphor layer 34 is provided on the surface of the substrate 35 opposite to the side on which the phosphor layer 34 is provided. The wavelength conversion element 27 of this embodiment is a fixed type wavelength conversion element.

  The green light LG5 emitted from the phosphor layer 34 is non-polarized light whose polarization directions are not aligned. Therefore, after passing through the first pickup optical system 26, the green light LG5 enters the polarization separation element 50 in the non-polarization state. The green light LG5 passes through the polarization separation element 50 and travels toward the integrator optical system 31.

  On the other hand, the blue light LB3 and the red light LR2 transmitted through the polarization separation element 50 are incident on the second retardation plate 28. The second retardation plate 28 is provided on the optical path of the red light LR2 and the blue light LB3 between the polarization separation element 50 and the diffusion device 30. The second retardation plate 28 is formed of a wide band retardation plate capable of giving a phase difference to light in both the blue region and the red region. Specifically, the second retardation plate 28 is configured of a quarter wavelength plate that provides a quarter wavelength phase difference to both the blue light LB3 and the red light LR2. Thus, the P-polarized blue light LB3 and the red light LR2 emitted from the polarization separation element 50 are converted into, for example, clockwise circularly-polarized blue light LB3 and red light LR2, and then the second pickup optical system 29 is obtained. Incident to

  The second pickup optical system 29 focuses the blue light LB3 and the red light LR2 toward the diffusion plate 301 of the diffusion device 30. The second pickup optical system 29 is composed of a pickup lens 29a and a pickup lens 29b.

  The diffusion device 30 includes a diffusion plate 301 (a diffusion element), a reflective layer 303 (a reflection portion), and a motor 302 that rotates the diffusion plate 301. The reflective layer 303 is provided on the second surface 301 b on the side opposite to the first surface 301 a on the side on which the blue light LB 3 and the red light LR 2 of the diffusion plate 301 are incident. The reflective layer 303 is made of, for example, a metal layer having a high reflectance, such as silver or aluminum. The reflective layer 303 reflects the blue light LB3 and the red light LR2 incident from the first surface 301a of the diffusion plate 301, and red light LR6 (sixth light) and blue light LB7 (seventh light) described later. Are ejected from the first surface 301a. That is, the diffusion device 30 includes a reflective diffusion plate 301.

  The diffusion plate 301 diffuses the red light LR2 and the blue light LB3 emitted from the second pickup optical system 29, and diffuses the red light LR2 with the red diffused light LR6 (sixth light), and the blue light LB3. Generates the diffused blue light LB7 (seventh light). Hereinafter, the red diffused light LR6 and the blue diffused light LB7 are simply referred to as a red light LR6 and a blue light LB7, respectively. The clockwise circularly polarized blue light LB3 and the red light LR2 are converted by the reflection layer 303 into counterclockwise circularly polarized red light LR6 and blue light LB7, respectively. The diffusion plate 301 preferably performs Lambert reflection of the red light LR2 and the blue light LB3. By using this type of diffusion plate 301, it is possible to obtain red light LR6 and blue light LB7 having uniform illuminance distribution while diffusing and reflecting red light LR2 and blue light LB3. Further, by rotating the diffusion plate 301 by the motor 302, speckle can be sufficiently suppressed.

  The red light LR6 and the blue light LB7 emitted from the diffusion device 30 pass through the second pickup optical system 29, and are incident on the second retardation plate 28 again, whereby counterclockwise circularly polarized red light LR6 The left-handed circularly polarized blue light LB7 is converted into s-polarized red light LR6 and s-polarized blue light LB7, respectively. The s-polarized red light LR6 and the s-polarized blue light LB7 enter the polarization separation element 50. The s-polarized red light LR 6 and the s-polarized blue light LB 7 are reflected by the polarization separation element 50 and travel toward the integrator optical system 31.

  Thus, the blue light LB7, the red light LR6 and the green light LG5 are emitted from the polarization separation element 50 in the same direction. As a result, the blue light LB7 and the red light LR6 are used as the illumination light WL together with the green light LG5 transmitted through the polarization separation element 50. That is, the blue light LB7, the red light LR6 and the green light LG5 are combined to obtain white illumination light WL. In other words, the polarization separation element 50 also functions as a color combining element that combines the blue light LB7, the red light LR6 and the green light LG5.

  The illumination light WL emitted from the polarization separation element 50 enters the integrator optical system 31. The integrator optical system 31 divides the illumination light WL into a plurality of small luminous fluxes. The integrator optical system 31 includes a first lens array 31a and a second lens array 31b. Each of the first lens array 31a and the second lens array 31b has a configuration in which a plurality of microlenses are arranged in an array.

  The illumination light WL (a plurality of small luminous fluxes) emitted from the integrator optical system 31 enters the polarization conversion element 32. The polarization conversion element 32 aligns the polarization directions of the illumination light WL into one. The polarization conversion element 32 is composed of a polarization separation film, a retardation plate and a mirror (not shown). The polarization conversion element 32 converts one linearly polarized light component to the other linearly polarized light component, for example, a P-polarized light component to an S-polarized light component.

  A light quantity monitoring mirror 42 is provided on the optical path between the integrator optical system 31 and the polarization conversion element 32. The light amount monitoring mirror 42 is disposed at an angle of 45 ° with respect to the optical axis ax2. The light amount monitoring mirror 42 transmits a part of the incident light and reflects the remaining light. The light transmitted through the light amount monitor mirror 42 is incident on the polarization conversion element 32, and the light reflected by the light amount monitor mirror 42 is incident on the light amount detector 43. The detailed configuration of the light amount detection unit 43 will be described later.

  The light amount monitor mirror 42 is disposed at a position where a secondary light source image of the blue light LB1 and the red light LR2 emitted from the light source unit 70 is formed. Here, an example is shown in which the light amount monitoring mirror 42 is disposed on the optical path between the integrator optical system 31 and the polarization conversion element 32. Instead of this example, the light amount monitoring mirror 42 may be disposed on the optical path between the polarization conversion element 32 and the superimposing lens 33a.

  The illumination light WL whose polarization direction is aligned by passing through the polarization conversion element 32 is incident on the superposition lens 33 a. The superimposing lens 33a superimposes a plurality of small light beams emitted from the polarization conversion element 32 on the red light light modulation device 4R, the green light light modulation device 4G, and the blue light light modulation device 4B. Thus, the illumination light WL can uniformly illuminate the red light light modulation device 4R, the green light light modulation device 4G, and the blue light light modulation device 4B. The superposing optical system 33 includes an integrator optical system 31 including a first lens array 31a and a second lens array 31b, and a superimposing lens 33a.

  In the case of the present embodiment, the light quantity monitoring mirror 42 is disposed at the formation position of the secondary light source image on the light path between the integrator optical system 31 and the polarization conversion element 32. Therefore, even if the light amount monitor mirror 42 is disposed in the light path and a part of the light is extracted, the red light light modulation device 4R, the green light light modulation device 4G, and the blue light light, which are the illumination region Irradiance unevenness does not occur on the modulation device 4B. Therefore, if the illuminance reduction for one secondary light source image can be tolerated, the light amount monitor mirror 42 does not necessarily transmit a part of the light, and does not have to reflect the rest, and reflects all the light. It may be a mirror.

  The light amount detection unit 43 includes two dichroic mirrors (not shown) and three sensors. The illumination light WL1 incident on the light amount detection unit 43 is separated into blue light component, green light component and red light component by two dichroic mirrors. A blue light sensor, a green light sensor, and a red light sensor are respectively provided on the optical paths of the blue light component, the green light component, and the red light component separated by the two dichroic mirrors. The blue light sensor detects the intensity of the blue light component. The green light sensor detects the intensity of the green light component. The red light sensor detects the intensity of the red light component. Thus, the light amount detection unit 43 detects the light amount of the blue light LB7, the light amount of the red light LR6, and the light amount of the green light LG5 included in the illumination light WL1.

  The control unit 44 controls the motor 47 that rotates the first retardation plate 46, and the blue semiconductor laser 711B and the red semiconductor laser 711R that constitute the light source unit 70. For example, in the steady state, the control unit 44 controls the rotation angle of the first retardation plate 46 and the drive current supplied to each of the blue semiconductor laser 711B and the red semiconductor laser 711R.

  Furthermore, in the control unit 44, the ratio of the light amount of the blue light LB7, the light amount of the red light LR6, and the light amount of the green light LG5 is stored in advance as a reference value for obtaining a desired white balance. When the detection result of the light amount ratio detected by the light amount detection unit 43 deviates from the reference value, the control unit 44 determines the rotation angle of the first retardation plate 46 based on the detection result of the light amount detection unit 43. And adjusting at least one of the amount of red light LR2 emitted by the red semiconductor laser 711R.

  Specifically, the control unit 44 rotates the first retardation plate 46 so that the ratio of the light intensity of the blue light LB7 to the light intensity of the green light LG5 approaches the reference value. Change the direction of the optical axis of Changing the direction of the optical axis of the first retardation plate 46 changes the ratio of the light quantity of the blue light LB3 to be incident on the diffusion device 30 to the light quantity of the blue light LB4 to be incident on the wavelength conversion element 27 As a result, the ratio between the light quantity of the blue light LB7 and the light quantity of the green light LG5 can be adjusted. In addition, the control unit 44 changes the drive current supplied to the red semiconductor laser 711R such that the ratio of the light amount of the red light LR6 to the light amount of the blue light LB7 and the light amount of the green light LG5 approaches a reference value. Thereby, the ratio of the light amount of the blue light LB7, the light amount of the green light LG5, and the light amount of the red light LR6 can be adjusted.

  The reference value of the ratio of the light intensity of the blue light LB7, the light intensity of the red light LR6, and the light intensity of the green light LG5 is determined based on the light intensity ratio at the start of use of the projector 1 measured by the light intensity detector 43. It may be a value that has been Alternatively, the design value of the projector 1 may be used as a reference value of the ratio of the light amount of the blue light LB7, the light amount of the red light LR6, and the light amount of the green light LG5.

  Here, it is assumed that, for example, the amount of light emitted from the blue semiconductor laser 711B is reduced due to the time-dependent change in use of the projector. A countermeasure for the deviation of the white balance occurring in this case will be described.

First, the basic white balance of this embodiment will be described.
Generally, the light emission efficiency of the semiconductor laser differs for each light emission color, so the light output of the semiconductor laser also differs for each light emission color. For example, the luminous efficiency of the blue semiconductor laser is higher than the luminous efficiency of the green semiconductor laser and the luminous efficiency of the red semiconductor laser. Therefore, the light output of the blue semiconductor laser is higher than the light output of the green semiconductor laser and the light output of the red semiconductor laser.

  The ability of the light output of the semiconductor laser of each color currently marketed is as shown in Table 1 below. However, the values shown in Table 1 are an example of a specific product.

  In the example of Table 1, the light output of one blue semiconductor laser (central wavelength: 455 nm) is 4.5 W, and the light output of one green semiconductor laser (central wavelength: 520 nm) is 0.7 W, The light output of one red semiconductor laser (central wavelength: 640 nm) is 1.6 W.

  In addition, the light output of each semiconductor laser necessary to obtain white light with a brightness of 1000 lm, 2000 lm, and 3000 lm, and the number of each semiconductor laser necessary to obtain this white light are shown in Table 2 below. It is street.

  As shown in Table 2, for example, when calculated from the light output of each semiconductor laser necessary to obtain white light of a specific brightness and the light output of one semiconductor laser shown in Table 1, for example, the brightness The number of semiconductor lasers required to obtain white light of 1000 lm is one for the blue light semiconductor laser, three for the green light semiconductor laser, and three for the red light semiconductor laser. As described above, the number of semiconductor lasers required to obtain white light of a specific brightness is different for each emission color.

Here, the amount of light for each color light obtained by the light source device 2 of the present embodiment is calculated.
The light source device 2 includes three blue semiconductor lasers 711B that emit blue light LB1, four red semiconductor lasers 711R that emit red light LR2, and a wavelength conversion element 27 that emits green light LG5. There is. Further, by adjusting the rotation angle of the first retardation plate 46, the ratio of the light amount KB3 of the blue light LB3 to be incident on the diffusion device 30 to the light amount KB4 of the blue light LB4 to be incident on the wavelength conversion element 27 is KB3: KB4 It shall be set to 2: 8. Also, the conversion efficiency of the phosphor layer is 50%.

In this case, the light amounts of the blue light LB7, the green light LG5, and the red light LR6 that constitute the illumination light WL are calculated based on the values in Table 1 as follows.
The total light quantity KB1 of the blue light LB1 is KB1 = 4.5 (W) × 3 (pieces) = 13.5 (W), and 20% of the total light quantity KB1 is distributed to the blue light LB3 directed to the diffusion device 30 80% are distributed to the blue light LB4 directed to the wavelength conversion element 27. Therefore, the light amount KB3 of the blue light LB3 is KB3 = 13.5 (W) × 0.2 = 2.7 (W). If the loss in the diffusion device 30 or the optical system in the middle is ignored, the light amount of the blue light LB7 emitted from the diffusion device 30 becomes equal to the light amount of the blue light LB3, which is 2.7 (W).

  On the other hand, the light quantity KB4 of the blue light LB4 is KB4 = 13.5 (W) × 0.8 = 10.8 (W). In the wavelength conversion element 27, since 50% of the blue light LB4 is converted to the green light LG5, the light amount KG5 of the green light LG5 is KG5 = 10.8 (W) × 0.5 = 5.4 (W) It becomes.

  Further, the light amount KR2 of the red light LR2 is KR2 = 1.6 (W) × 4 (pieces) = 6.4 (W). If the loss in the diffusion device 30 or the optical system in the middle is ignored, the light amount of the red light LR6 emitted from the diffusion device 30 becomes equal to the light amount of the red light LR2, which is 6.4 (W).

  The light output of each semiconductor laser required to obtain white light with a brightness of 2190 lm is as shown in Table 3 below.

  According to Table 3, the light output of each semiconductor laser necessary to obtain white light with a brightness of 2190 lm is 2.7 W for the blue light semiconductor laser and 4.45 W for the green light semiconductor laser. , The red light semiconductor laser is 6.4W. Therefore, since the above calculation results substantially match the values in Table 3, in the light source device 2 of this embodiment, the ratio of the light quantity KB3 to the light quantity KB4 is set to KB3: KB4 = 2: 8. By adjusting the rotation angle of the phase difference plate 46 of No. 1 and supplying the drive current to the red semiconductor laser 711R, it is possible to obtain white light with excellent white balance up to 2190 lm in brightness.

  By the way, in the light source device 2 of the present embodiment, if the light output of the blue semiconductor laser 711 B decreases, the light amount of the blue light LB 4 for exciting the phosphor layer 34 decreases accordingly. The decrease in the light amount of the blue light LB4 is equivalent to the decrease in the light density (the light amount per unit area) of the excitation light. In general, a phosphor has a characteristic that when the light density of excitation light decreases, the conversion efficiency at the time of converting the excitation light into fluorescence increases. Therefore, even if the amount of excitation light decreases, the amount of green light LG5 emitted from the phosphor layer 34 when the increase in fluorescence due to the increase in conversion efficiency exceeds the decrease in fluorescence due to the decrease in the amount of excitation light. Will increase. Here, although the case where the light amount of the green light LG5 increases will be described as an example, the light amount of the green light LG5 may decrease. However, in either case the white balance is broken.

  Here, as the light output of the blue semiconductor laser 711B decreases, the light amount of the blue light LB3 and the light amount of the blue light LB4 both decrease. However, since the conversion efficiency of the phosphor is increased, the light amount of the green light LG5 relative to the blue light LB3 is relatively increased. As a result, the ratio between the blue light LB7 and the green light LG5 changes, and the white balance of the illumination light WL including the blue light LB7 and the green light LG5 is broken compared to before the change with time. Specifically, since the light amount of the green light LG5 is relatively increased with respect to the light amount of the blue light LB7, the illumination light WL is changed to greenish white light.

  Here, the light amount detection unit 43 measures the light amount of each of the color lights LB7, LG5, and LR6 included in the illumination light WL1 extracted from the light amount monitoring mirror. Further, as described above, the control unit 44 stores in advance the reference value of the light amount ratio determined based on the initial light amount at the start of use of the projector 1. Therefore, the control unit 44 compares the actual measurement value of the light amount ratio at present detected by the light amount detection unit 43 with the stored reference value. As a result, when the difference between the current light amount ratio and the light amount ratio of the reference value exceeds the allowable range, the first retardation plate 46 is rotated so that the current light amount ratio approaches the reference value.

  By rotating the first retardation plate 46 by a predetermined angle, the ratio of the light amount of the blue light LB3 generated by the first retardation plate 46 to the light amount of the blue light LB4 can be adjusted. Specifically, in order to increase the light amount of the blue light LB7 and reduce the light amount of the green light LG5, the light amount of the blue light LB3 may be relatively increased and the light amount of the blue light LB4 may be relatively reduced. Further, by rotating the first retardation plate 46 by a predetermined angle, the light amount of the blue light LB3 and the light amount of the blue light LB4 change, so the blue light LB7 and the green light are changed according to the change amount. The current supplied to the red semiconductor laser 711R may be adjusted so that the light amount ratio between LG5 and red light LR6 approaches the light amount ratio of the reference value. As a result, compared to when the white balance is broken, the illumination light WL becomes closer to white, and the white balance can be improved. In addition, it is possible to reduce color unevenness caused by all the colors of the blue light LB7, the green light LG5, and the red light LR6.

  In the wavelength conversion element of Patent Document 1, since a phosphor for converting blue light into yellow light is used, a problem occurs due to irradiation of a large amount of excitation light to the phosphor. Also in the wavelength conversion element of Patent Document 2, in addition to blue light, red light that does not contribute as excitation light is irradiated to the phosphor, so the amount of light irradiation to the phosphor is large, and the same problem as in Patent Document 1 Was occurring.

  On the other hand, in the light source device 2 of the present embodiment, since the phosphor layer 34 that generates the green light LG5 using the blue light LB4 as excitation light is used, compared to the light sources of Patent Documents 1 and 2 The amount of excitation light can be reduced. Therefore, the light source device 2 capable of adjusting the white balance is realized while solving the problems such as the decrease in conversion efficiency of the phosphor, the occurrence of temperature quenching, the difficulty in adjusting the color temperature, and the easy damage to the phosphor. can do.

  In the light source device 2 of the present embodiment, since the plurality of blue semiconductor lasers 711 B and the plurality of red semiconductor lasers 711 R that constitute the light source unit 70 are arranged rotationally symmetric about the central axis CB of the light source unit 70, blue The incident angle when the light LB3 enters the diffusion plate 301 and the incident angle when the red light LR2 enters the diffusion plate 301 can be made substantially equal. As a result, the angular distribution of the blue light LB7 emitted from the diffusion plate 301 and the angular distribution of the red light LR6 can also be made substantially equal, so that color unevenness can be suppressed. Furthermore, since the plurality of blue semiconductor lasers 711B and the plurality of red semiconductor lasers 711R are arranged in the closest packing, the light source device 2 can be miniaturized.

  In the light source device 2 of the present embodiment, since the first retardation plate 46 is configured of a narrow band retardation plate that selectively applies a retardation to the blue light LB1, the first retardation plate is There is no need to process the shape of 46 in accordance with the optical path of each light or to arrange the first retardation plate 46 only on the optical path of the blue light LB1, and the configuration of the first retardation plate 46 is simplified. Can be

  In the light source device 2 of the present embodiment, the diffusion device 30 includes the reflective layer 303, and includes the second retardation plate 28 capable of providing a phase difference to light in both the blue wavelength range and the red wavelength range. Because of this, a reflective diffuser plate 301 can be used. Thereby, the configuration of the optical system of the light source device 2 can be simplified.

  Instead of the configuration of the present embodiment, a modification of the modified example includes a light source unit including a blue semiconductor laser and a green semiconductor laser, and a wavelength conversion element including a phosphor layer that emits red light using blue light as excitation light. A light source device may be used. However, in the present technology, a phosphor emitting green light has higher conversion efficiency than a phosphor emitting red light. In addition, the red semiconductor laser has higher luminous efficiency than the green semiconductor laser. Therefore, according to the light source device 2 of the present embodiment, higher efficiency can be obtained compared to the light source device of the above-described modified example.

  The projector 1 according to the present embodiment includes the light source device 2 configured as described above, so that a projector with excellent display quality can be realized.

In place of the first retardation plate 46 used in the present embodiment, a first retardation plate 49 described below may be used.
FIG. 6 is a front view of a light source unit 70 showing a first retardation plate 49 of a modification. The configuration of the light source unit 70 is the same as that of the first embodiment.
As shown in FIG. 6, the first retardation plate 49 includes an annular portion 49 c and three overhang portions 49 h projecting outward from the annular portion 49 c. The annular portion 49c is disposed at a position avoiding the light path of the blue light LB1 and the light path of the red light LR2. Each of the three overhanging portions 49h is disposed on the optical path of the blue light LB1 emitted from the three blue semiconductor lasers 711B. That is, the first retardation plate 49 is disposed on the optical path of the blue light LB1, and has a shape not disposed on the optical path of the red light LR2. The first retardation plate 49 can be manufactured, for example, by cutting out a region corresponding to the optical path of the red light LR2 of the first retardation plate 46 of the first embodiment.

  According to the first retardation plate 49 of this modification, since the red light LR2 does not pass through the first retardation plate 49, it is not necessary to use the narrow band retardation plate as in the first embodiment, and the wavelength A general retardation plate having no dependency can be used. Therefore, as the first retardation plate 49, not only a resin retardation plate but also a retardation plate made of, for example, quartz can be used, and the heat resistance of the first retardation plate 49 can be secured. .

Second Embodiment
Hereinafter, a second embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector of the second embodiment is the same as that of the first embodiment, and the configuration of the light source device is different from that of the first embodiment. Therefore, the description of the projector is omitted, and only the light source device is described.
FIG. 7 is a schematic block diagram of the light source device 12 of the second embodiment.
7, the same code | symbol is attached | subjected to the same component as drawing used in 1st Embodiment, and detailed description is abbreviate | omitted.

  As shown in FIG. 7, the components included in the light source device 12 of the present embodiment are the same as the light source device 2 of the first embodiment, and in the light source device 12 of the present embodiment, the second retardation plate 28 and The positions of the components between the diffusion device 30 and the positions of the components between the first pickup optical system 26 and the wavelength conversion element 27 are replaced from those of the light source device 2 of the first embodiment.

  That is, in the light source device 12 of the present embodiment, the light source unit 72, the first retardation plate 46, the homogenizer optical system 24, the polarization separation element 50, the first pickup optical system 26, and the wavelength conversion element 27. And are sequentially arranged side by side on the optical axis ax1. On the other hand, the diffuser 30, the second pickup optical system 29, the second retardation plate 28, the polarization separation element 50, the integrator optical system 31, the polarization conversion element 32, and the superposition optical system 33 The optical axes ax2 are sequentially arranged side by side.

  The light source unit 70 according to the first embodiment includes a red semiconductor laser that emits red light LR2 as P-polarized light. On the other hand, the light source unit 72 of the present embodiment includes a red semiconductor laser that emits red light LR2s (second light in the first polarization direction of the second wavelength range) as S-polarization. That is, in the red semiconductor laser of the present embodiment, the longitudinal direction W1 of the light emitting region 715Ra of the red semiconductor laser chip 715R shown in FIG. 4 is rotated 90 ° from the direction shown in FIG. It is arranged parallel to the Y axis. The red semiconductor laser chip 715R emits linearly polarized light whose polarization direction is the short direction W2 of the light emitting region 715Ra, so the red semiconductor laser 711R emits S polarized light whose polarization direction is the Z direction. As a result, the red light LR2s emitted from the red semiconductor laser 711R is reflected by the polarization separation element 50 and travels toward the diffusion device 30.

  As for the blue semiconductor laser 711B, as in the first embodiment, the polarization direction of the blue light LB1 (first light in the first wavelength range) emitted from the blue semiconductor laser 711B may be indeterminate, and the first retardation plate After passing through the light source 46, blue light LB3s of S polarization (third light of first polarization direction) and blue light LB4p of P polarization (fourth light of second polarization direction) are mixed at a predetermined ratio. Just do it. Therefore, unlike the red semiconductor laser 711R, the blue semiconductor laser 711B may have the same direction as the light emitting region 715Ba of the blue semiconductor laser chip 715B shown in FIG. 4 in the present embodiment. Thereby, the blue light LB3 s of S-polarization is reflected by the polarization separation element 50 and travels toward the diffusion device 30. The P-polarized blue light LB 4 p passes through the polarization separation element 50 and travels toward the wavelength conversion element 27.

  For example, clockwise circularly polarized blue light LB3s and red light LR2s are converted into left-handed circularly polarized red light LR6 and blue light LB7 by being reflected by the reflective layer 303, respectively. The red light LR6 and the blue light LB7 emitted from the diffusion device 30 pass through the second pickup optical system 29, and are incident on the second retardation plate 28 again, whereby counterclockwise circularly polarized red light LR6 The left-handed circularly polarized blue light LB7 is converted to P-polarized red light LR6 and P-polarized blue light LB7, respectively. The P-polarized red light LR6 and the P-polarized blue light LB7 pass through the polarization separation element 50 and travel toward the integrator optical system 31.

The polarization separation element 50 reflects green light regardless of the polarization state. Therefore, after passing through the first pickup optical system 26, the green light LG5 enters the polarization separation element 50 in the non-polarization state, is reflected by the polarization separation element 50, and travels toward the integrator optical system 31. .
The other configuration of the light source device 12 is the same as that of the first embodiment.

  Also in this embodiment, the same effect as that of the first embodiment can be obtained such that the light source device 12 capable of adjusting the white balance can be realized while solving the problems associated with the increase in the excitation light irradiated to the phosphor. Be

Third Embodiment
Hereinafter, a third embodiment of the present invention will be described with reference to FIG.
The basic configuration of the projector of the third embodiment is the same as that of the first embodiment, and the configuration of the light source device is different from that of the first embodiment. Therefore, the description of the projector is omitted, and only the light source device is described.
FIG. 8 is a schematic block diagram of the light source device 14 of the third embodiment.
In FIG. 8, the same components as those in the drawing used in the first embodiment are given the same reference numerals, and the detailed description is omitted.

  As shown in FIG. 8, the light source device 14 includes a light source unit 15, a first retardation plate 16 (first retardation element), a motor 47 (drive unit), a homogenizer optical system 24, and polarization separation. An element 50, a first pickup optical system 26, a wavelength conversion element 27, a second retardation plate 28 (second retardation element), a second pickup optical system 29, a diffuser 30, and An integrator optical system 31, a polarization conversion element 32, a superposition optical system 33, a light amount monitor mirror 42, a light amount detection unit 43, and a control unit 44 are provided.

  The light source unit 15 includes a blue light source unit 15B (first light source unit), a red light source unit 15R (second light source unit), and a dichroic mirror 17. The blue light source unit 15B includes a plurality of blue semiconductor lasers 711B (first light emitting devices). The red light source unit 15R includes a plurality of red semiconductor lasers 711R (second light emitting devices). The red light source unit 15R is disposed such that the chief ray of each red light LR2 emitted from each red semiconductor laser 711R is orthogonal to the optical axis ax1.

  In the blue light source unit 15B, the plurality of blue semiconductor lasers 711B are arranged in the closest packing as shown in FIG. Similarly, in the red light source unit 15R, the plurality of red semiconductor lasers 711R are arranged in the closest packing as shown in FIG. Each red semiconductor laser 711R emits red light LR2 as P polarization. The polarization direction of the blue light LB1 emitted from the blue semiconductor laser 711B may be indefinite. The number of blue semiconductor lasers 711 B and red semiconductor lasers 711 R is not particularly limited, and is appropriately set.

  The dichroic mirror 17 combines the plurality of blue lights LB1 emitted from the blue light source unit 15B and the plurality of red lights LR2 emitted from the red light source unit 15R. The dichroic mirror 17 transmits the blue light LB1 and reflects the red light LR2. Thereby, the blue light LB1 and the red light LR2 are synthesized, and travel toward the homogenizer optical system 24.

The first retardation plate 16 is disposed on the optical path of the blue light LB1 between the blue light source unit 15B and the dichroic mirror 17. The first retardation plate 16 is disposed over the optical path of the plurality of blue lights LB1 emitted from the plurality of blue semiconductor lasers 711B. The blue light LB1 is p-polarized blue light LB3 (third light in the first polarization direction) and s-polarized blue light LB4 (fourth light in the second polarization direction) by the first retardation plate 16 The light is converted to light including and emitted from the first retardation plate 16.
The other configuration of the light source device is the same as that of the first embodiment.

  Also in the present embodiment, the light source device 14 capable of adjusting the white balance can be realized while solving the problems associated with the increase in the excitation light irradiated to the phosphor, and the same effect as the first embodiment is obtained. Be

  Furthermore, in the light source device 14 of the present embodiment, the blue light source unit 15B including the plurality of blue semiconductor lasers 711B and the red light source unit 15R including the plurality of red semiconductor lasers 711R are disposed at separate positions. The degree of freedom in the arrangement of the lasers 711 B and 711 R can be increased. Furthermore, according to this configuration, since the first retardation plate 16 is disposed on the optical path corresponding to only the blue light LB1, the red light LR2 does not enter the first retardation plate 16; As the first retardation plate 16, a general retardation plate having no wavelength dependency can be used. Further, as the first retardation plate 16, not only a resin retardation plate but also a retardation plate made of, for example, quartz can be used, and the heat resistance of the first retardation plate 16 can be enhanced.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the present invention.
In the above embodiment, an example in which the light source device includes the reflection type wavelength conversion element has been described. However, the transmission type wavelength conversion element may be provided. Moreover, although the example which the light source device provided with the reflection type diffusion plate was given, you may be equipped with the transmission type diffusion plate.

  Further, although the light source unit in which the plurality of semiconductor lasers are arranged in a circle is provided in the above embodiment, for example, a light source unit in which a plurality of semiconductor lasers are arranged in an array may be provided.

  Further, the number, the arrangement, the shape, the material, the dimensions, and the like of the components of the light source device and the projector exemplified in the above embodiment can be appropriately changed.

  Although the projector including the three light modulation devices is illustrated in the above embodiment, it is also possible to apply to a projector which displays a color image by one light modulation device. Also, a digital mirror device may be used as the light modulation device.

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

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2, 12, 14 ... Light source device, 4B ... Light modulation device for blue light, 4G ... Light modulation device for green light, 4R ... Light modulation device for red light, 6 .... Projection optical system, 15, 70, 72: light source unit, 15B: blue light source unit (first light source unit), 15R: red light source unit (second light source unit), 16, 46: first retardation plate (first retardation element), 17: Dichroic mirror, 27: wavelength conversion element, 28: second retardation plate (second phase difference element), 43: light quantity detection unit, 44: control unit, 47: motor (drive unit), 50: polarization separation element 301: diffusion plate (diffuse element) 303: reflection layer (reflection portion) 712: support member LB1 blue light (first light) LB3, LB3s blue light (third light) LB4, LB4p: blue light (fourth light), LB7: blue light (seventh light), LG5: green (Fifth optical), LR2, LR2s ... red light (second light), LR6 ... red light (sixth light), WL, WL1 ... illumination light.

Claims (10)

A first light emitting device for emitting a first light in a first wavelength range; and a second light emitting device for emitting a second light in a first polarization direction of a second wavelength range different from the first wavelength range; A light source unit having
The first light is provided on the optical path of the first light and the second light, and the first light is converted to the third light of the first polarization direction and the second light of the second polarization direction different from the first polarization direction. A first retardation element that converts light into light including
A wavelength conversion element including a phosphor excited by the fourth light and generating fifth light of a third wavelength range different from the first wavelength range and the second wavelength range;
A diffusion element for diffusing the second light and the third light, and generating a sixth light into which the second light is diffused and a seventh light into which the third light is diffused; ,
The fourth light is separated from the second light and the third light among the second light, the third light, and the fourth light emitted from the first retardation element. And guides the second light and the third light to the diffusion element, and guides the fifth light emitted from the wavelength conversion element and the light emitted from the diffusion element. A polarization separation element that combines illumination light with a sixth light and the seventh light;
A light source device comprising: The light source unit includes a plurality of first light emitting devices, a plurality of second light emitting devices, a support member supporting the plurality of first light emitting devices, and the plurality of second light emitting devices. Equipped with
The light source device according to claim 1, wherein the plurality of first light emitting devices and the plurality of second light emitting devices are disposed in rotational symmetry around a central axis of the light source unit.   The first retardation element is configured of a retardation plate that provides a phase difference to the first light when the first light and the second light having different wavelength ranges are incident. The light source device according to claim 2, characterized in that:   3. The device according to claim 2, wherein the first retardation element is disposed on the optical path of the first light and not disposed on the optical path of the second light. The light source device as described.   The light source unit includes a first light source unit including a plurality of the first light emitting devices, a second light source unit including a plurality of the second light emitting devices, and a plurality of the first light source units from the first light source unit. The light source device according to claim 1, further comprising: a dichroic mirror that combines light and the plurality of second lights from the second light source unit. And a drive unit configured to rotate the direction of the optical axis of the first retardation element.
The drive unit adjusts the ratio of the light amount of the third light to the light amount of the fourth light after emitting the first retardation element by rotating the direction of the optical axis. The light source device according to any one of claims 1 to 5, wherein A light amount detection unit configured to detect a light amount of the fifth light, a light amount of the sixth light, and a light amount of the seventh light, which constitute the illumination light;
A control unit that controls at least the drive unit and the second light emitting device;
And further
The control unit adjusts at least one of the rotation angle of the first phase difference element and the light amount of the second light emitted from the second light emitting device based on the detection result of the light amount detection unit. The light source device according to claim 6, characterized in that: A reflecting unit that reflects the second light and the third light incident from the first surface of the diffusion element and emits the sixth light and the seventh light from the first surface;
It is provided on the optical path of the second light and the third light between the polarization separation element and the diffusion element, and is positioned with respect to both the light of the first wavelength band and the light of the second wavelength band. A second retardation element capable of providing a phase difference;
The light source device according to any one of claims 1 to 7, further comprising: The first light emitting device comprises a solid light source emitting blue light,
The second light emitting device comprises a solid state light source for emitting red light,
The light source device according to any one of claims 1 to 8, wherein the phosphor is made of a phosphor that emits green light. A light source device according to any one of claims 1 to 9;
A light modulation device that forms image light by modulating light from the light source device according to image information;
And a projection optical system for projecting the image light.

Images