JP2022150713A - Light source device and projector - Google Patents

Abstract

To provide a light source device and a projector that can emit illumination light including green light with high purity.SOLUTION: A light source device emitting illumination light comprises: a first light source that emits blue light; a second light source that emits green light; and a wavelength conversion element that converts the wavelength of the blue light emitted from the first light source to generate fluorescent light. The illumination light includes a blue light component, a green light component, and a red light component. The blue light component includes the blue light emitted from the first light source. The green light component includes the green light emitted from the second light source. The red light component includes red light having a wavelength of 590 nm or more in the fluorescent light.SELECTED DRAWING: Figure 3

Description

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

2. Description of the Related Art Conventionally, a projector is known that modulates light emitted from a light source device to form an image according to image information and projects the formed image. As a light source device used in such a projector, a light source device including a wavelength conversion element that converts excitation light emitted from a light source into fluorescent light and emits the fluorescent light is known (see, for example, Patent Document 1).
The wavelength conversion element described in Patent Document 1 has a phosphor layer containing a plurality of phosphor particles. A phosphor particle is a particle containing a phosphor material and an activator serving as a luminescence center. Examples of activators include Ce, Eu, Pr, Cr, Gd and Ga, and examples of phosphor materials include YAG phosphor materials.

JP 2020-154031 A

However, when blue light is incident as excitation light, the fluorescence emitted from the YAG:Ce phosphor material containing Ce as an activator contains a large amount of green light components and a small amount of red light components. That is, the fluorescence emitted from the YAG:Ce phosphor material has a spectral characteristic that has a peak at about 550 nm and the light amount decreases substantially linearly until reaching about 750 nm. Therefore, for example, when fluorescence at 590 nm is divided into green light and red light, the actual chromaticity coordinate values of green light are coordinate values closer to yellow light. When a light source device having such a wavelength conversion element is used in a projector, it may not be possible to reproduce the user's desired color depending on the type of image to be formed.
There has been a demand for a light source device capable of emitting illumination light including green light with high purity.

A light source device according to a first aspect of the present disclosure is a light source device that emits illumination light, comprising: a first light source that emits blue light; a second light source that emits green light; and a wavelength conversion element that converts the wavelength of the blue light to generate fluorescence, wherein the illumination light includes a blue light component, a green light component and a red light component, and the blue light component is the first light source. The green light component includes green light emitted from the second light source, and the red light component includes red light having a wavelength of 590 nm or greater in the fluorescence.

A projector according to a second aspect of the present disclosure includes the light source device according to the first aspect, a light modulation device that modulates light emitted from the light source device, and a projector that projects the light modulated by the light modulation device. and an optical device.

1 is a schematic diagram showing the configuration of a projector according to a first embodiment; FIG. 1 is a schematic diagram showing the configuration of a light source device according to a first embodiment; FIG. FIG. 2 is a cross-sectional view showing a diffusing element, a reflecting element, and a wavelength converting element in the first embodiment; FIG. 5 is a schematic diagram showing the configuration of a light source device included in a projector according to a second embodiment;

[First embodiment]
A first embodiment of the present disclosure will be described below based on the drawings.
[Schematic configuration of the projector]
FIG. 1 is a schematic diagram showing the configuration of a projector 1 according to this embodiment.
The projector 1 according to the present embodiment modulates light emitted from a light source device 4, which will be described later, to form an image according to image information, and enlarges and projects the formed image onto a projection surface such as a screen. The projector 1 includes an exterior housing 2 and an image projection device 3 arranged in the exterior housing 2, as shown in FIG. In addition, although illustration is omitted, the projector 1 cools a control device that controls the operation of the projector 1, a power supply device that supplies power to electronic components that make up the projector 1, and a cooling target that makes up the projector 1. Equipped with a cooling device.

[Configuration of exterior housing]
The exterior housing 2 configures the exterior of the projector 1 . The exterior housing 2 accommodates the image projection device 3, a control device, a power supply device, and a cooling device. The exterior housing 2 has a top surface portion and a bottom surface portion (not shown), a front portion 21, a rear portion 22, a left side portion 23, and a right side portion 24, and is formed in a substantially rectangular parallelepiped shape.
The front portion 21 has an opening 211 that exposes a part of the projection optical device 36 to be described later, and an image projected by the projection optical device 36 passes through the opening 211 . The front portion 21 also has an exhaust port 212 through which the cooling gas that has cooled the object to be cooled in the projector 1 is discharged to the outside of the exterior housing 2 . Further, the right side surface portion 24 has an introduction port 241 through which the gas outside the exterior housing 2 is introduced into the inside as a cooling gas.

[Configuration of image projection device]
The image projection device 3 forms and projects an image according to image information. The image projection device 3 includes a light source device 4 , a homogenization device 31 , a color separation device 32 , a relay device 33 , an image forming device 34 , an optical component housing 35 and a projection optical device 36 .
The light source device 4 emits light. The configuration of the light source device 4 will be detailed later.

The homogenizing device 31 homogenizes the light emitted from the light source device 4 . The light homogenized by the uniformizing device 31 passes through the color separating device 32 and the relay device 33 and illuminates a modulation area of a light modulating device 343 (described later) of the image forming device 34 . The uniformizing device 31 comprises two lens arrays 311 , 312 , a polarization conversion element 313 and a superposing lens 314 .
The color separating device 32 separates the light incident from the uniformizing device 31 into red, green and blue colored lights. The color separator 32 includes two dichroic mirrors 321 and 322 and a reflecting mirror 323 that reflects blue light separated by the dichroic mirror 321 . Note that the dichroic mirror 322 separates green light and red light. The transmission wavelength of the dichroic mirror 322 is 590 nm or longer. Therefore, green light with a wavelength of less than 590 nm is reflected by the dichroic mirror 322 , and red light with a wavelength of 590 nm or more passes through the dichroic mirror 322 and enters the relay device 33 .

The relay device 33 is provided in the optical path of the red light, which is longer than the optical path of the blue light and the optical path of the green light, and suppresses the loss of the red light. The relay device 33 includes an incident-side lens 331 , a relay lens 333 and reflection mirrors 332 and 334 .
In this embodiment, the relay device 33 is provided in the optical path of the red light. However, the present invention is not limited to this. It is good also as a structure provided.

The image forming device 34 modulates the incident red, green and blue colored lights and combines the modulated colored lights to form an image projected by the projection optical device 36 . The image forming device 34 includes three field lenses 341, three incident-side polarizing plates 342, three light modulators 343, three exit-side polarizing plates 344, and one color synthesis unit. a device 345;
The light modulation device 343 modulates the light emitted from the light source device 4 according to image information. The three light modulators 343 include a light modulator 343R that modulates red light, a light modulator 343G that modulates green light, and a light modulator 343B that modulates blue light. In this embodiment, the light modulation device 343 is composed of a transmissive liquid crystal panel, and the incident side polarizing plate 342, the light modulation device 343 and the output side polarizing plate 344 constitute a liquid crystal light valve.
The color synthesizing device 345 synthesizes the color lights modulated by the light modulating devices 343B, 343G, and 343R to form an image. In this embodiment, the color synthesizing device 345 is composed of a cross dichroic prism, but is not limited to this, and can be composed of, for example, a plurality of dichroic mirrors.

The optical component housing 35 accommodates the homogenizing device 31, the color separation device 32, the relay device 33 and the image forming device 34 therein. An illumination optical axis Ax, which is a designed optical axis, is set in the image projection device 3, and the optical component housing 35 is provided at a predetermined position on the illumination optical axis Ax. 32 , a relay device 33 and an image forming device 34 . The light source device 4 and the projection optical device 36 are arranged at predetermined positions on the illumination optical axis Ax.

The projection optical device 36 enlarges and projects the image incident from the image forming device 34 onto the projection surface. That is, the projection optical device 36 projects light modulated by the light modulators 343B, 343G, and 343R. The projection optical device 36 is configured, for example, as a combination lens in which a plurality of lenses are accommodated in a cylindrical lens barrel.

[Configuration of light source device]
FIG. 2 is a schematic diagram showing the configuration of the light source device 4. As shown in FIG.
The light source device 4 includes, as shown in FIG. An element 49 is provided.
The light source device 4 emits illumination light to the homogenizing device 31 . The illumination light emitted by the light source device 4 is white light containing a blue light component, a green light component and a red light component. Although details will be described later, the blue light component includes blue light emitted from the first light source 41 . The green light component includes green light emitted from the second light source 42 . The red light component includes red light separated from the fluorescence FL emitted from the wavelength conversion element 49 .
In the following description, the three mutually orthogonal directions are +X direction, +Y direction and +Z direction. The +X direction is the direction in which the light source device 4 emits illumination light. Although not shown, the direction opposite to the +X direction is the -X direction, the direction opposite to the +Y direction is the -Y direction, and the direction opposite to the +Z direction is the -Z direction.

[Configuration of first light source]
The first light source 41 emits blue light BL along the +Z direction. The first light source 41 has a first solid light emitting element 411 , a first light source support substrate 412 , a first collimating lens 413 and a first afocal optical element 414 .
The first solid-state light-emitting element 411 is a solid-state light source that emits blue light BL, which is excitation light that excites the phosphor contained in the wavelength conversion element 49 . Specifically, the first solid-state light-emitting element 411 is a semiconductor laser, and the blue light BL emitted by the first solid-state light-emitting element 411 is laser light with a peak wavelength of 455 nm, for example. Note that a plurality of first solid-state light emitting devices 411 may be provided.
The first light source support substrate 412 supports the first solid light emitting device 411 . The first light source support substrate 412 is a thermally conductive metal member, and a heat dissipation member (not shown) is thermally connected to the first light source support substrate 412 . Therefore, the heat of the first solid light emitting device 411 is transferred to the heat dissipation member via the first light source support substrate 412 .

The first collimating lens 413 collimates the blue light BL emitted from the first solid-state light emitting device 411 .
The first afocal optical element 414 reduces the diameter of the blue light BL collimated by the first collimating lens 413 . The first afocal optical element 414 includes a first lens 415 that collects the blue light BL incident from the first collimating lens 413, and a second lens that collimates the blue light BL collected by the first lens 415. 416. Note that the first afocal optical element 414 may be omitted.

[Configuration of second light source]
The second light source 42 emits green light GL along the +X direction. Specifically, the second light source 42 emits the green light GL in a direction crossing the emission direction of the blue light BL from the first light source 41 . The second light source 42 has a second solid light emitting element 421 , a second light source support substrate 422 , a second collimating lens 423 and a second afocal optical element 424 .
The second solid-state light emitting device 421 is a solid-state light source that emits green light GL. More specifically, the second solid-state light-emitting element 421 is a semiconductor laser, and the green light GL emitted by the second solid-state light-emitting element 421 is laser light of 500 nm or more and 540 nm or less. Preferably, the green light GL emitted by the second solid-state light-emitting element 421 is laser light with a wavelength of 510 nm or more and 530 nm or less, and in this embodiment, laser light with a peak wavelength of 525 nm. A plurality of second solid-state light-emitting devices 421 may be provided.

The second light source support substrate 422, the second collimating lens 423, and the second afocal optical element 424 have the same configuration and function as the first light source support substrate 412, the first collimating lens 413, and the first afocal optical element 414. have
That is, the second light source support substrate 422 supports the second solid light emitting device 421 . The second light source support substrate 422 is a metal member having thermal conductivity, and transfers the heat of the second solid light emitting element 421 to a heat dissipation member (not shown).
The second parallelizing lens 423 parallelizes the green light GL emitted from the second solid-state light emitting device 421 .
The second afocal optical element 424 includes a first lens 425 that reduces the diameter of the green light GL collimated by the second collimating lens 423 and a second lens 425 that collimates the green light GL that has been reduced in diameter by the first lens 425 . 2 lenses 426 . Note that the second afocal optical element 424 may be omitted.

[Structure of light combining member]
The light combining member 43 is provided at the intersection of the optical path of the blue light BL emitted from the first light source 41 and the optical path of the green light GL emitted from the second light source 42, and separates the blue light BL and the green light GL. Synthesize. Specifically, the light combining member 43 allows the blue light BL emitted from the first light source 41 to pass through in the +Z direction, the blue light BL to pass through the light combining member 43 in the +Z direction, and the second light source 42 to emit in the +X direction. The reflected green light GL is reflected to synthesize the blue light BL and the green light GL. The light combining member 43 is composed of a dichroic mirror that transmits the blue light BL and reflects the green light GL.
Hereinafter, light obtained by synthesizing the blue light BL and the green light GL by the light synthesizing member 43 will be referred to as synthetic light SL.

[Configuration of Angle Conversion Element]
The angle conversion element 44 is arranged in the +Z direction with respect to the light combining member 43 . The angle conversion element 44 interferes with the combined light beam SL incident from the light combining member 43, and causes the traveling direction of the combined light beam SL to vary by several degrees or less. It is possible to prevent the wavelength conversion layer 491 from being damaged due to the synthesis light SL condensing at one point on the wavelength conversion layer 491 of the wavelength conversion element 49 due to variations in the traveling direction of the synthesis light SL.
Such an angle conversion element 44 may have, for example, a configuration in which parabolic concave surfaces formed in a rectangular shape when viewed from the light incident side are arranged vertically and horizontally on a plane orthogonal to the +Z direction. Alternatively, the angle conversion element 44 may have spherical concave surfaces or pyramidal concave surfaces arranged vertically and horizontally. That is, the angle conversion element 44 may have a configuration that minimizes interference of harmonics with respect to the incident light flux.

[Configuration of reflecting member]
The reflecting member 45 is arranged in the +Z direction with respect to the angle conversion element 44 . The reflecting member 45 has a reflecting portion 451 and a transmitting portion 452 .
The reflecting section 451 reflects the combined light SL incident from the angle conversion element 44 in the −X direction to enter the condensing element 46 . The dimension of the reflecting portion 451 when viewed from the −Z direction is the minimum dimension that allows all of the combined light SL emitted from the angle conversion element 44 to enter.

The transmissive portion 452 is provided outside the reflective portion 451 when viewed from the -Z direction. In this embodiment, the transmissive portion 452 is a translucent substrate that supports the reflective portion 451 .
The transmitting portion 452 transmits the green light GL, which is reflected by the reflecting element 48 and is incident from the -X direction via the diffusing element 47 and the condensing element 46, in the +X direction. The transmitting portion 452 transmits the blue light BL incident from the wavelength conversion element 49 in the +X direction through the reflecting element 48, the diffusing element 47 and the condensing element 46 from the -X direction. The transmitting portion 452 transmits the red light RL generated by the wavelength conversion element 49 and incident from the -X direction through the reflecting element 48, the diffusing element 47 and the condensing element 46 in the +X direction. Therefore, the light emitted from the reflecting member 45 in the +X direction includes blue light BL, green light GL, and red light RL.
The reflecting member 45 having such a transmitting portion 452 can be said to be a light combining member that combines green light GL, blue light BL, and red light RL and emits them in the +Z direction. Each color light transmitted through the transmitting portion 452 in the +X direction constitutes illumination light emitted from the light source device 4 .

[Construction of Condensing Element]
The condensing element 46 converges the combined light SL reflected by the reflecting portion 451 onto the wavelength conversion element 49 . Also, the condensing element 46 parallelizes the red light RL, the green light GL, and the blue light BL incident in the +X direction from the diffusion element 47 and emits them to the transmission section 452 .
In the example of FIG. 2, the condensing element 46 is composed of one lens. However, the number of lenses forming the condensing element 46 can be changed as appropriate.

[Structure of diffusion element]
FIG. 3 is a diagram showing cross sections of the diffusing element 47, the reflecting element 48, and the wavelength converting element 49 along the XZ plane.
The diffusion element 47 diffuses and emits incident light. The diffusing element 47 is provided between the condensing element 46 and the reflecting element 48 in the optical path of the combined light SL reflected by the reflecting member 45, as shown in FIGS. More specifically, the diffusing element 47 is arranged on the incident side of the combined light SL with respect to the wavelength converting element 49 so that the gap between the diffusing element 47 and the wavelength converting element 49 is, for example, about 0.1 mm.

The +X-direction surface of the diffusing element 47 is an incident surface 471 on which the combined light SL is incident. That is, the diffusing element 47 has an incident surface 471 on which the combined light SL is incident.
The incident surface 471 has a configuration in which a plurality of minute concave curved surfaces 472 are arranged in an array when viewed from the incident side of the combined light SL. The pitch of the concave curved surface 472 is, for example, approximately 0.1 mm, and the maximum inclination angle of the concave curved surface 472 is approximately 20°.
An antireflection layer 473 is formed on the incident surface 471 provided with such a plurality of concave curved surfaces 472 . That is, the diffusing element 47 has an antireflection layer 473 .

The combined light beam SL incident on the incident surface 471 is incident on the inside of the diffusion element 47 after adding an incident angle of up to about 13° by the plurality of concave curved surfaces 472 . Also, the light emitted to the outside of the diffusion element 47 is diffused by the plurality of concave curved surfaces 472 and emitted.
In this embodiment, the diffusion element 47 is a translucent member made of glass such as quartz glass, and the dimension of the diffusion element 47 along the +X direction is approximately 0.3 mm. The plurality of concave curved surfaces 472 can be formed by etching the surface of the light-transmitting member, which serves as the incident surface 471 . However, the present invention is not limited to this, and the diffusion element 47 may be made of another material such as resin, and the plurality of concave curved surfaces 472 may be formed by other methods.

[Structure of reflective element]
The reflecting element 48 transmits part of the combined light SL incident from the diffusing element 47 and reflects the other light, and is formed of a dielectric multilayer film. Specifically, the reflecting element 48 reflects the green light GL and transmits the blue light BL of the incident combined light SL. That is, the reflective element 48 reflects green light in a wavelength band of 522 nm or more and 528 nm or less, and transmits blue light in a wavelength band of 450 nm or more and 460 nm or less and yellow light in a wavelength band of approximately 530 nm or more. Therefore, the reflective element 48 reflects substantially all of the incident green light having a wavelength of 525 nm and transmits red light having a wavelength of 590 nm or longer.
The green light GL reflected by the reflecting element 48 enters the diffusing element 47 and is diffused by a plurality of concave curved surfaces 472 provided on the incident surface 471 . The diffused green light GL enters the condensing element 46 as scattered light with an angle of up to about 60° and is collimated. As a result, the green light GL emitted from the condensing element 46 toward the reflecting member 45 is collimated as light having a width wider than that when incident on the reflecting portion 451 of the reflecting member 45 .

A reflecting layer that reflects approximately 20% of the blue light having a wavelength of approximately 455 nm may be provided on the incident side of the combined light SL in the reflecting element 48 . In this case, the chromaticity of the white light can be adjusted by reflecting part of the blue light BL of the incident combined light SL with the reflecting element 48 .
On the other hand, the reflecting element 48 may be configured to reflect the s-polarized blue light BL and the s-polarized green light GL, and transmit the p-polarized blue light BL and the p-polarized green light GL.
In addition, in this embodiment, the reflecting element 48 is provided on the surface 474 of the diffusion element 47 which is a flat surface on the wavelength conversion element 49 side. However, it is not limited to this, and may be provided on the incident surface 471 having a plurality of concave curved surfaces 472, or may be provided after forming fine convex surfaces on the incident surface 492 of the wavelength conversion element 49. FIG. Furthermore, the reflective element 48 may be provided independently between the diffusing element 47 and the wavelength converting element 49 .

[Configuration of Wavelength Conversion Element]
The wavelength conversion element 49 converts first light in a first wavelength band into second light in a second wavelength band different from the first wavelength band. Specifically, the wavelength conversion element 49 converts the wavelength of the blue light BL incident from the reflection element 48 and emits fluorescence FL, which is converted light. In this embodiment, the wavelength conversion element 49 is a reflective wavelength conversion element that emits the fluorescence FL to the incident side of the blue light BL.
The fluorescence FL is, for example, light with a peak wavelength of 500 to 700 nm, and includes green light and red light. The fluorescence FL is an example of second light in a second wavelength band different from the first wavelength band.

The wavelength conversion element 49 has a wavelength conversion layer 491 , a reflective layer 493 and a substrate 494 .
The wavelength conversion layer 491 contains a phosphor that produces fluorescence FL having a wavelength longer than that of the blue light BL. Specifically, the wavelength conversion layer 491 has a chromaticity closer to red than the chromaticity of the fluorescence generated by the wavelength conversion layer containing a YAG-containing phosphor (YAG phosphor) and Ce as an activator. It contains a phosphor that produces fluorescence. For example, the wavelength conversion layer 491 contains a phosphor containing YGdAG (YGdAG phosphor) and Ce as an activator. Further, for example, the wavelength conversion layer 491 contains a phosphor (LSN phosphor) containing La ₃ Si ₆ N ₁₁ and Ce as an activator. Further, for example, the wavelength conversion layer 491 contains a phosphor containing YAG and Cr (Cr+YAG phosphor) and Ce as an activator. Note that the wavelength conversion layer 491 may contain pores having a diameter of 1 μm or less at a volume ratio of 1% or more.

The +Z-direction surface of the wavelength conversion layer 491 is an incident surface 492 on which the blue light BL transmitted through the reflecting element 48 is incident. That is, the wavelength conversion element 49 has an incident surface 492 on which the blue light BL is incident.
When the reflective element 48 allows part of the green light GL to pass through, the green light GL that has passed through the reflective element 48 enters the wavelength conversion layer 491 . Also, the green light GL emitted from the wavelength conversion layer 491 and reflected by the reflecting element 48 enters the wavelength conversion layer 491 again. When the phosphor contained in the wavelength conversion layer 491 is a phosphor that is excited by green light, it is excited by the green light GL incident on the wavelength conversion layer 491 . In this case, the wavelength converting layer 491 produces light in the spectrum ranging from yellow to red. At this time, the luminous efficiency of the wavelength conversion layer 491 increases. Also, at this time, the light of 530 nm or less generated by the wavelength conversion layer 491 is very little, and the effect on the overall brightness and color can be ignored. Note that light of 530 nm or less may be reabsorbed and part of the light may be converted to red.

The reflective layer 493 is provided on the opposite side of the wavelength conversion layer 491 from the incident side of the blue light BL. That is, the reflective layer 493 is provided between the wavelength conversion layer 491 and the substrate 494 . The reflective layer 493 reflects the light incident from the wavelength conversion layer 491 in the +X direction.
A substrate 494 supports the wavelength converting layer 491 and the reflective layer 493 . The substrate 494 is made of a metal such as Ag having thermal conductivity, and transfers heat generated in the wavelength conversion layer 491 to a heat dissipation member (not shown). The heat dissipation member cools the wavelength conversion layer 491 by dissipating heat from the wavelength conversion layer 491 that is transmitted through the reflective layer 493 and the substrate 494 .

[Illumination Light Emitted from Light Source Device]
As described above, the combined light SL reflected by the reflecting portion 451 of the reflecting member 45 is incident on the reflecting element 48 via the diffusing element 47 . Of the combined light SL incident on the reflecting element 48, the blue light BL passes through the reflecting element 48 and enters the wavelength conversion element 49, and the green light GL is reflected by the reflecting element 48 toward the diffusion element 47 side. be done. The green light GL incident on the diffusing element 47 becomes scattered light by a plurality of concave curved surfaces 472 provided on the incident surface 471 of the diffusing element 47 when emitted to the outside of the diffusing element 47, and is emitted in the +X direction. be done. The scattered green light GL is collimated by the condensing element 46 and passes through the transmitting portion 452 of the reflecting member 45 in the +X direction.

At least part of the blue light BL that has passed through the reflecting element 48 enters the wavelength conversion layer 491 of the wavelength conversion element 49 and is converted into fluorescence FL. Fluorescence FL includes green light GL and red light RL, as described above.
The green light GL generated by the wavelength conversion layer 491 is directly emitted from the wavelength conversion layer 491 to the outside, or is reflected by the reflective layer 493 and emitted to the outside of the wavelength conversion layer 491 . The green light GL emitted from the wavelength conversion layer 491 to the outside is reflected by the reflecting element 48 and enters the wavelength conversion layer 491 again. When the phosphor contained in the wavelength conversion layer 491 is excited by this green light, red light RL is generated as described above.

The red light RL generated in the wavelength conversion layer 491 is emitted from the wavelength conversion layer 491 to the outside as scattered light. The red light RL emitted from the wavelength conversion layer 491 is transmitted through the reflective element 48 and further scattered in the course of passing through the diffusion element 47 in the +X direction. The red light RL scattered by the diffusing element 47 is collimated by the condensing element 46 and passes through the transmitting portion 452 of the reflecting member 45 in the +X direction.

Here, in the present embodiment, the +Z-direction dimension of the wavelength conversion layer 491 is the dimension that allows approximately 20% of the incident blue light BL to be emitted to the outside. That is, 20% of the blue light BL incident on the wavelength conversion layer 491 is emitted outside the wavelength conversion layer 491 without being converted into fluorescence FL by the wavelength conversion layer 491 .
Like the red light RL emitted from the wavelength conversion layer 491 , such blue light BL passes through the reflecting element 48 in the +Z direction and enters the diffusing element 47 . The blue light BL incident on the diffusing element 47 is scattered by the diffusing element 47 . The blue light BL scattered by the diffusing element 47 is collimated by the condensing element 46 and passes through the transmitting portion 452 of the reflecting member 45 in the +X direction.

In this way, the red light RL, green light GL, and blue light BL that have passed through the transmitting portion 452 are emitted from the light source device 4 as white light. The white light emitted from the light source device 4 enters the homogenizing device 31 as illumination light.
Therefore, the illumination light emitted by the light source device 4 contains a blue light component, a green light component and a red light component. The blue light component includes the blue light BL emitted from the first light source 41, the green light component includes the green light GL emitted from the second light source 42, and the red light component includes the wavelength conversion element 49. It contains the red light RL contained in the emitted fluorescence FL. The red light RL contained in the fluorescence FL includes red light RL having a wavelength of 590 nm or longer that can pass through the reflecting element 48 and the dichroic mirror 322 .

[Emission characteristics by phosphor]
Here, the emission characteristics when the YAG phosphor, the YGdAG phosphor, and the LSN phosphor are each irradiated with blue light will be described. Note that Ce is added as an activator to each phosphor.
A YAG phosphor irradiated with blue light emits fluorescence having a wavelength characteristic that has a peak at approximately 530 nm and that the intensity decreases approximately linearly as the wavelength increases.
For this reason, when the fluorescence emitted from the YAG phosphor is separated into green light having a wavelength of less than 590 nm and red light having a wavelength of 590 nm or more, the balance between the intensity of the green light and the intensity of the red light is, for example, an image. Good balance for formation.

However, the separated green light becomes green light containing yellow light of 550 nm or more and less than 590 nm. That is, the separated green light becomes yellowish green light, and the purity of the green light is low.
On the other hand, the chromaticity of the white light obtained by synthesizing the green light and red light separated from the fluorescence generated by the YAG phosphor and the blue light emitted from the solid-state light-emitting element has a value close to the target value. However, if the white light is combined with the green light emitted from the solid-state light emitting device in order to increase the purity of the green light, there is a problem that the chromaticity of the white light tends to be green.

On the other hand, the YGdAG phosphor irradiated with blue light emits fluorescence having a wavelength characteristic that has a peak at approximately 545 nm and that the intensity decreases approximately linearly as the wavelength increases. Also, the LSN phosphor irradiated with blue light emits fluorescence having a wavelength characteristic that has a peak at approximately 560 nm and that the intensity decreases approximately linearly as the wavelength increases. That is, the wavelength characteristics of the fluorescence generated by the YGdAG phosphor and the wavelength characteristics of the fluorescence generated by the LSN phosphor are the wavelength characteristics in which the wavelength characteristics of the fluorescence generated by the YAG phosphor are shifted to the high wavelength side. Become.
For this reason, if the fluorescence emitted from the YGdAG phosphor or the LSN phosphor is separated into green light with a wavelength of less than 590 nm and red light with a wavelength of 590 nm or more, the amount of green light emitted from the fluorescence emitted from the YGdAG phosphor or the LSN phosphor is reduced compared to when the YAG phosphor is used. decreases and the intensity of red light increases. In this case, the intensity of green light is reduced with respect to the intensity of red light.

On the other hand, by synthesizing the red light separated from the fluorescence emitted from the wavelength conversion layer containing the YGdAG phosphor or the LSN phosphor and the green light emitted from the second light source 42, In addition to being able to adjust the balance between the intensity and the intensity of the red light, the purity of the green light can be increased. By synthesizing the red light and the green light with the blue light emitted from the first light source 41, the chromaticity of the white light can be adjusted to the target value.
In addition, the wavelength conversion layer 491 containing the LSN phosphor is formed by firing an LSN powder phosphor having a particle size of 20 μm or more and 30 μm or less on a low-melting glass to form a bulk and fixing it on the reflective layer 493 . Manufactured by Low-melting glass is glass with a melting point of 600° C. or lower.

On the other hand, a YAG phosphor containing Cr in addition to Ce as an activator (Cr+YAG phosphor) has a maximum peak at approximately 550 nm when irradiated with blue light, and exhibits a substantially linear distribution as the wavelength increases. As the intensity decreases, fluorescence with wavelength characteristics having a second peak at approximately 690 nm is emitted.
For this reason, if light with a wavelength of less than 590 nm is separated as green light and light with a wavelength of 590 nm or more is separated as red light from the fluorescence emitted from the Cr+YAG phosphor, the intensity of the green light is lower than when the YAG phosphor is used. decreases and the intensity of red light increases. In this case, the intensity of green light is reduced with respect to the intensity of red light.

On the other hand, as in the case of using the YGdAG phosphor or the LSN phosphor, the red light separated from the fluorescence emitted from the wavelength conversion layer containing the Cr+YAG phosphor and the green light emitted from the second light source 42 By combining the light, the balance between the intensity of the green light and the intensity of the red light can be adjusted, and the purity of the green light can be increased. By synthesizing the red light and the green light with the blue light emitted from the first light source 41, the chromaticity of the white light can be adjusted to the target value.
The Cr+YAG phosphor is excited by light in a wavelength band of approximately 350 nm or more and 460 nm or less and light in a wavelength band of approximately 510 nm or more and 600 nm or less. The excitation spectrum of such a Cr+YAG phosphor has a maximum peak at approximately 410 nm and a second peak at approximately 555 nm. Therefore, the Cr+YAG phosphor is excited not only by blue light but also by green light. For this reason, in order not to excite the Cr+YAG phosphor even when the light is incident on the Cr+YAG phosphor, the second solid-state light emitting element 421 of the second light source 42 preferably emits a green laser beam having a peak at approximately 510 nm. .

In this way, the wavelength conversion layer 491 irradiated with blue light contains at least one of the YGdAG phosphor, the LSN phosphor, and the Cr+YAG phosphor, and an activator such as Ce, thereby producing white light. chromaticity can be adjusted to a target value, and the purity of green light can be increased.

[Effect of the first embodiment]
The projector 1 according to this embodiment described above has the following effects.
The projector 1 includes a light source device 4 , a light modulation device 343 that modulates light emitted from the light source device 4 , and a projection optical device 36 that projects the light modulated by the light modulation device 343 .
The light source device 4 emits illumination light that illuminates the light modulation device 343 . The light source device 4 includes a first light source 41 that emits blue light BL, a second light source 42 that emits green light GL, and converts the wavelength of the blue light BL emitted from the first light source 41 to generate fluorescence FL. and a wavelength conversion element 49 that The illumination light emitted from the light source device 4 contains a blue light component, a green light component and a red light component. The blue light component includes blue light emitted from the first light source 41 . The green light component includes green light GL emitted from the second light source 42 . The red light component includes red light RL having a wavelength of 590 nm or longer in fluorescence FL.

According to such a configuration, the blue light component contained in the illumination light can be made into blue light with high purity, and the green light component contained in the illumination light can be made into green light with high purity. Further, since the red light component contained in the illumination light is red light having a wavelength of 590 nm or more, the red light component can also be red light with high purity. Therefore, each color light contained in the illumination light can be made into color light with high purity. Moreover, this can improve the color reproducibility of the image projected by the projector 1 .

In the light source device 4, the wavelength conversion element 49 may contain a phosphor containing YGdAG (YGdAG phosphor) and Ce as an activator.
Here, the peak wavelength of the fluorescence FL emitted from the wavelength conversion element 49 containing the YGdAG phosphor and Ce is emitted from the wavelength conversion element containing the phosphor containing YAG (YAG phosphor) and Ce. Larger than the fluorescence peak wavelength. Therefore, when the light amount of the fluorescence FL emitted from the wavelength conversion element 49 containing the YGdAG phosphor and the light amount of the fluorescence emitted from the wavelength conversion element containing the YAG phosphor are the same, the wavelength conversion The amount of red light RL in the fluorescence FL emitted from the element 49 can be increased.

In the light source device 4, the wavelength conversion element 49 may contain a phosphor (LSN phosphor) containing La ₃ Si ₆ N ₁₁ and Ce as an activator.
According to such a configuration, the peak wavelength of the fluorescence FL emitted from the wavelength conversion element 49 containing the LSN phosphor and Ce is the peak wavelength of the fluorescence emitted from the wavelength conversion element containing the YAG phosphor and Ce. Larger than the peak wavelength. Therefore, when the amount of fluorescence FL emitted from the wavelength conversion element 49 containing the LSN phosphor and the amount of fluorescence emitted from the wavelength conversion element containing the YAG phosphor are the same, the wavelength conversion The amount of red light RL in the fluorescence FL emitted from the element 49 can be increased.

In the light source device 4, the wavelength conversion element 49 may contain a phosphor containing YAG and Cr (Cr+YAG phosphor) and Ce as an activator.
Here, the light amount of the red light component in the fluorescence FL emitted from the wavelength conversion element 49 containing the Cr+YAG phosphor and Ce is the red light in the fluorescence emitted from the wavelength conversion element containing the YAG phosphor and Ce. Greater than the light intensity of the component. Therefore, when the amount of fluorescence FL emitted from the wavelength conversion element 49 containing the Cr+YAG phosphor and the amount of fluorescence emitted from the wavelength conversion element containing the YAG phosphor are the same, the wavelength conversion The amount of red light RL in the fluorescence FL emitted from the element 49 can be increased.

The light source device 4 includes a light combining member 43 , a diffusion element 47 and a reflection element 48 . The light synthesizing member 43 emits synthesized light SL obtained by synthesizing the blue light BL emitted from the first light source 41 and the green light GL emitted from the second light source 42 . The diffusion element 47 is provided on the incident side of the combined light SL with respect to the wavelength conversion element 49, and diffuses the incident light. The reflecting element 48 is provided between the diffusing element 47 and the wavelength converting element 49 and reflects at least part of the incident green light GL.
According to such a configuration, the green light GL emitted from the second light source 42 and diffused by the diffusion element 47 can be included in the illumination light emitted from the light source device 4 . Therefore, green light with high purity can be included in the illumination light.

In the light source device 4 , the wavelength conversion element 49 has a wavelength conversion layer 491 and a reflective layer 493 . The wavelength conversion layer 491 converts the blue light BL in the combined light SL into fluorescence FL. The reflective layer 493 includes a reflective layer 493 that is provided on the opposite side of the wavelength conversion layer 491 from the incident side of the blue light BL and that reflects incident light. The wavelength conversion layer 491 emits a part of blue light BL out of the incident blue light BL.
According to such a configuration, the fluorescence FL generated by the wavelength conversion element 49 can be incident on the diffusion element 47 via the reflection element 48 and diffused by the diffusion element 47 . In addition, since the wavelength conversion layer 491 emits a part of the incident blue light BL, the blue light BL emitted from the wavelength conversion layer 491 is caused to enter the diffusion element 47 via the reflection element 48, and the diffusion element It can be diffused at 47 . Therefore, the illuminance distribution of the illumination light emitted from the light source device 4 can be made uniform. Although the reflecting element 48 is used in this embodiment, the wavelength conversion layer 491 contains 1% or more, preferably 2% or more by volume of pores having a diameter smaller than 1 μm, which is twice the wavelength. You may let Before the blue light BL is wavelength-converted into fluorescent light FL, part of the blue light BL is irregularly reflected and reflected in the light incident direction of the blue light BL, thereby causing Mie scattering by the pores. The function can be substituted, in which case the reflective element 48 can be omitted.

[Second embodiment]
Next, a second embodiment of the present disclosure will be described.
The projector according to this embodiment has the same configuration as the projector 1 according to the first embodiment, but differs in the configuration of the light source device. In the following description, the same or substantially the same parts as those already described are denoted by the same reference numerals, and the description thereof is omitted.

[Configuration of light source device]
FIG. 4 is a schematic diagram showing the configuration of the light source device 5 included in the projector according to this embodiment.
The projector according to the present embodiment has the same configuration and functions as the projector 1 according to the first embodiment, except that the light source device 5 shown in FIG. 4 is provided instead of the light source device 4 according to the first embodiment.
Like the light source device 4 , the light source device 5 emits illumination light for illuminating the light modulation device 343 to the homogenization device 31 . The light source device 5 includes a first light source 41, a wavelength conversion element 51, a first collimating element 52, a second light source 53, a condensing element 54, a diffusion device 55, a second collimating element 56, a light combining element 57, and a reflecting element 58. have

The light source device 5 has a first illumination optical axis along the direction of emission of blue light from the first light source 41 and a second illumination optical axis that intersects with the first illumination optical axis. The first illumination optical axis is an optical axis along the +X direction, and the second illumination optical axis is an optical axis along the +Z direction.
The first light source 41, the wavelength converting element 51, the first collimating element 52 and the photosynthesizing element 57 are arranged on the first illumination optical axis.
A second light source 53, a condensing element 54, a diffuser 55, a second collimating element 56, a light combining element 57 and a reflecting element 58 are arranged on the second illumination optical axis.
The photosynthesis element 57 is arranged at the intersection of the first illumination optical axis and the second illumination optical axis.

[Configuration of Wavelength Conversion Element]
The wavelength conversion element 51 is excited by the blue light BL emitted from the first light source 41 and emits fluorescence FL having a wavelength band different from that of the blue light BL. In the wavelength conversion element 51 as well, the blue light BL is an example of first light in a first wavelength band, and the fluorescence FL is an example of second light in a second wavelength band different from the first wavelength band.

The wavelength conversion element 51 has a wavelength conversion layer 511 , a reflective layer 512 and a substrate 513 . The wavelength conversion element 51 is arranged on the first illumination optical axis so that the substrate 513, the reflective layer 512, and the wavelength conversion layer 511 are arranged in order of incidence of the blue light BL.
In the wavelength conversion layer 511, part of the blue light BL is converted into fluorescent light FL, and the rest of the blue light BL is emitted toward the first parallelizing element 52 side. The wavelength conversion layer 511 contains at least one of YGdAG phosphor, LSN phosphor and Cr+YAG phosphor, and Ce as an activator. Therefore, the fluorescence FL emitted from the wavelength conversion layer 511 mainly contains yellow light YL and red light RL, and also contains a small amount of green light GL.
Note that the dimension of the wavelength conversion layer 511 along the +X direction is such that the blue light that is not converted into fluorescence FL, out of the blue light BL incident on the wavelength conversion layer 511, is scattered and emitted from the wavelength conversion layer 511. Dimensions. In this embodiment, the dimension of the wavelength conversion layer 511 along the +X direction is such that 20% of the blue light BL incident on the wavelength conversion layer 511 is emitted.
When the wavelength conversion layer 511 contains an LSN phosphor, the wavelength conversion layer 511 is formed by sintering an LSN phosphor powder having a particle size of 10 μm or more and 30 μm or less with boric acid glass or low-melting glass, and forming it on the substrate 513 . It is constructed by applying to

A reflective layer 512 is disposed between the substrate 513 and the wavelength converting layer 511 . The reflective layer 512 is formed of a dielectric multilayer film having a transmission wavelength of 530 nm or less. The reflective layer 512 transmits blue light BL incident on the wavelength conversion layer 511 from the first light source 41, and reflects fluorescence FL generated in the wavelength conversion layer 511 and incident in the −X direction in the +X direction.
Among the blue light BL scattered by the wavelength conversion layer 511 and emitted, the blue light BL incident on the reflection layer 512 is the angle of the blue light BL incident from the first light source 41 via the substrate 513. is incident on the reflective layer 512 at a large angle compared to . Therefore, since the transmission wavelength of the dielectric multilayer film constituting the reflective layer 512 is 530 nm or less, the transmission wavelength of the dielectric multilayer film for the blue light BL traveling through the reflective layer 512 toward the substrate 513 is a lower wavelength. shift to Therefore, the amount of blue light passing through the reflective layer 512 to the substrate 513 side can be reduced, and more blue light can enter the first parallelizing element 52 from the wavelength conversion layer 511 .

The substrate 513 is formed of a translucent substrate that transmits at least the blue light BL, and is a sapphire substrate in this embodiment. The substrate 513 supports the wavelength conversion layer 511 and the reflective layer 512 and radiates heat transferred from the wavelength conversion layer 511 through the reflective layer 512 . A heat dissipation member may be provided that is connected to a region other than the incident region of the blue light BL on the substrate 513 and that dissipates heat transferred from the substrate 513 .

[Configuration of First Parallelizing Element]
The first parallelizing element 52 is arranged in the +X direction with respect to the wavelength conversion element 51 . The first collimating element 52 collimates the blue light BL and fluorescence FL emitted from the wavelength conversion element 51 in the +X direction. The blue light BL and fluorescence FL collimated by the first collimating element 52 enter the photosynthesis element 57 along the +X direction.

[Configuration of second light source]
The second light source 53 emits green light GL along the +Z direction. That is, the second light source 53 emits the green light GL in a direction crossing the emission direction of the blue light BL from the first light source 41 . The second light source 53 has a second solid state light emitting device 421 , a second light source support substrate 422 and a second collimating lens 423 . That is, the second light source 53 has the same configuration and functions as the second light source 42 except that the second afocal optical element 424 is not provided. That is, the second light source 53 has a second solid light emitting device 421 , a second light source support substrate 422 and a second collimating lens 423 .
The second solid-state light-emitting element 421 emits green light GL combined with fluorescence FL emitted from the wavelength conversion element 51 in the +Z direction.

[Construction of Condensing Element, Diffusion Device, and Second Collimating Element]
The condensing element 54 converges the green light GL emitted from the second light source 53 onto the diffusion device 55 .
The diffusing device 55 diffuses the green light GL incident from the condensing element 54 . The diffusing device 55 has a diffusing element 551 that diffuses and transmits the green light GL, and a drive element 552 such as a motor that rotates the diffusing element 551 about a rotation axis along the second illumination optical axis. Rotation of the diffusion element 551 by the drive element 552 can suppress speckle noise from occurring in the green light GL. The diffusion element 551 can be exemplified by etching the surface of quartz glass to a depth of approximately 10 μm and a width of approximately 100 μm.
The second collimating element 56 collimates the green light GL incident from the diffusion device 55 . The green light GL collimated by the second collimating element 56 is incident on the photosynthesis element 57 along the +Z direction.

[Structure of Photosynthesis Device]
The photosynthesis element 57 synthesizes part of the blue light BL emitted from the first light source 41, the fluorescence FL generated by the wavelength conversion element 51, and the green light GL emitted from the second light source 53. More specifically, the photosynthesis element 57 combines blue light BL that passes through the wavelength conversion element 51 and enters from the first parallelization element 52 and fluorescence generated by the wavelength conversion element 51 that enters from the first parallelization element 52 . The FL and the green light GL incident from the second collimating element 56 are combined.
Specifically, the photosynthesis element 57 is a band-pass filter that reflects light in a wavelength band corresponding to green light and transmits light in other wavelength bands, and has a dielectric multilayer film provided on a translucent substrate. have a configuration. Therefore, the blue light BL incident from the first collimating element 52 and the yellow light YL and red light RL excluding the green light GL among the fluorescence FL incident from the first collimating element 52 are allowed to pass through in the +X direction. , reflect the green light GL incident from the second collimating element 56 in the +X direction. That is, the blue light BL, yellow light YL, and red light RL derived from the blue light BL emitted from the first light source 41 and the green light GL emitted from the second light source 53 are synthesized by the photosynthesis element 57. , is emitted from the light source device 5 .

[Structure of reflective element]
The reflective element 58 is arranged in the +Z direction with respect to the photosynthetic element 57 . The reflecting element 58 reflects toward the photosynthesis element 57 the green light GL incident on the photosynthesis element 57 in the +X direction and reflected in the +Z direction. That is, the photosynthesis element 57 reflects the green light GL contained in the fluorescence FL to the photosynthesis element 57 .
The green light GL that has entered the photosynthesis element 57 from the reflection element 58 enters the wavelength conversion layer 511 of the wavelength conversion element 51 and excites the phosphor contained in the wavelength conversion layer 511 . Note that, as described above, depending on the type of phosphor, the phosphor is not excited by the green light GL.
The photosynthesis element 57 may transmit at least part of the green light contained in the fluorescence FL incident from the first parallelizing element 52 in the +X direction. In this case, the reflective element 58 may be omitted.

Such a light source device 5 emits illumination light including each color light emitted from the photosynthesis element 57 in the +X direction. Therefore, the illumination light emitted by the light source device 5 contains a blue light component, a green light component and a red light component. The blue light component includes the blue light BL emitted from the first light source 41, the green light component includes the green light GL emitted from the second light source 53, and the red light component is emitted from the wavelength conversion element 51. red light RL included in the fluorescence FL. The red light RL contained in the fluorescence FL includes red light having a wavelength of 590 nm or longer that can pass through the photosynthesis element 57 and the dichroic mirror 322 .

[Effect of Second Embodiment]
The projector according to the present embodiment described above can achieve the same effects as the projector 1 according to the first embodiment, and also has the following effects.
The light source device 5 includes a photosynthesis element 57 that synthesizes the light emitted from the wavelength conversion element 51 and the green light GL emitted from the second light source 53 . The wavelength conversion element 51 has a wavelength conversion layer 511 and a reflective layer 512 . The wavelength conversion layer 511 converts blue light BL emitted from the first light source 41 into fluorescence FL. The reflective layer 512 is provided between the first light source 41 and the wavelength conversion layer 511 , transmits blue light BL emitted from the first light source 41 , and reflects fluorescence FL incident from the wavelength conversion layer 511 . The wavelength conversion layer 511 emits the fluorescence FL and part of the blue light BL emitted from the first light source 41 toward the photosynthesis element 57 .
According to such a configuration, the blue light BL emitted from the first light source 41, the red light RL contained in the fluorescent light FL, and the green light GL emitted from the second light source 42 are synthesized by the photosynthesis element 57. can be emitted by Therefore, illumination light containing highly pure colored light can be emitted from the light source device 5 .

[Modification of Embodiment]
The present disclosure is not limited to the above-described embodiments, and includes modifications, improvements, and the like within a range that can achieve the purpose of the present disclosure.
In the first embodiment, depending on the configuration of the reflecting element 48, the green light component of the illumination light emitted from the light source device 4 may be emitted from the wavelength conversion element 49 in addition to the green light GL emitted from the second light source 42. It is assumed that the green light contained in the obtained fluorescent FL is included. In the second embodiment, depending on the configuration of the photosynthesis element 57, the green light component of the illumination light emitted from the light source device 5 includes the green light contained in the fluorescence FL generated by the wavelength conversion element 51. . However, not limited to this, the green light component of the illumination light emitted from the light source devices 4 and 5 may be green light emitted from the second light sources 42 and 53 . That is, the green light component of the illumination light emitted from the light source devices 4 and 5 may or may not contain the green light derived from the fluorescence FL.

In each of the above embodiments, the wavelength conversion layers 491 and 511 of the wavelength conversion elements 49 and 51 are assumed to contain one of YGdAG phosphor, LSN phosphor and Cr+YAG phosphor and Ce as an activator. . However, the phosphor contained in the wavelength conversion element is not limited to this, and may be other phosphors, and the wavelength conversion element may contain a plurality of types of phosphors. Moreover, the activator is not limited to Ce, and may be at least one of Eu, Pr, Cr, Gd and Ga, for example.

In the above-described first embodiment, the light source device 4 generates combined light SL by combining the blue light BL emitted from the first light source 41 and the green light GL emitted from the second light source 42 by the light combining member 43. Then, the combined light SL is made incident on the diffusing element 47 and the reflecting element 48 , and the blue light BL included in the combined light SL is made incident on the wavelength conversion element 49 . However, without being limited to this, the blue light BL emitted from the first light source 41 and the green light GL emitted from the second light source 42 are not synthesized by the light combining member 43, and the blue light BL is sent to the wavelength conversion element 49. The blue light BL and fluorescence FL emitted from the wavelength conversion element 49 and the green light GL emitted from the second light source 42 may be combined.
That is, the light combining member 43, the diffusion element 47 and the reflection element 48 may be omitted.

In the first embodiment, the wavelength conversion element 49 has the wavelength conversion layer 491 , the reflection layer 493 and the substrate 494 . However, without being limited to this, the light source device 4 may be provided with a transmissive wavelength conversion element that emits the fluorescence FL along the incident direction of the blue light BL, similarly to the light source device 5 . That is, the optical components constituting the light source device 4 and the layout of the optical components are not limited to the above. Therefore, at least one of the angle conversion element 44, the reflecting member 45, and the condensing element 46 may be omitted, and may be replaced with another optical component.

In the second embodiment, the light source device 5 includes the photosynthesis element 57 that synthesizes the fluorescence FL and blue light BL emitted from the wavelength conversion element 51 and the green light GL emitted from the second light source 53. . Further, the wavelength conversion element 51 is provided between a wavelength conversion layer 511 that converts the blue light BL emitted from the first light source 41 into fluorescence FL, and between the first light source 41 and the wavelength conversion layer 511. and a reflective layer 512 that transmits the blue light BL emitted from the wavelength conversion layer 511 and reflects the fluorescence FL incident from the wavelength conversion layer 511 . Furthermore, it is assumed that the wavelength conversion layer 511 emits the fluorescence FL and part of the blue light BL emitted from the first light source 41 toward the photosynthesis element 57 . However, the present invention is not limited to this, and the wavelength conversion element 51 may emit only fluorescence FL without emitting blue light BL. In this case, the light combining element 57 is a cross dichroic prism, and part of the blue light BL emitted from the first light source 41 or blue light emitted from another light source is incident on the cross dichroic prism from the -X direction. You may let In this case, the cross dichroic prism transmits the fluorescence FL incident along the +X direction in the +X direction, reflects the green light GL emitted in the +Z direction from the second light source 53 in the +X direction, and enters from the −Z direction. By reflecting the blue light in the +X direction, combined light containing each color light can be emitted as illumination light.
That is, the optical components constituting the light source device 5 and the layout of the optical components are not limited to the above.

In each of the embodiments described above, the projector is assumed to include three light modulators 343 (343R, 343G, and 343B). However, the present disclosure is not limited to this, and can be applied to a projector including two or less or four or more light modulation devices.
In each of the above embodiments, the image projection device 3 has been described as having the configuration and layout shown in FIG. However, the configuration and layout of the image projection device 3 are not limited to the above.

In each of the embodiments described above, the light modulation device 343 is provided with a transmissive liquid crystal panel in which the light incident surface and the light exit surface are different. However, the light modulation device 343 is not limited to this, and may be provided with a reflective liquid crystal panel in which the light incident surface and the light exit surface are the same. In addition, as long as it is an optical modulation device that can modulate an incident light beam to form an image according to image information, a device using a micromirror, such as a device using a DMD (Digital Micromirror Device), etc., can be used. It may be a modulator.

In each of the embodiments described above, an example in which the light source devices 4 and 5 of the present disclosure are applied to a projector has been given. However, the light source device of the present disclosure is not limited to this, and can be employed in, for example, lighting fixtures, headlights of automobiles, and the like.

[Summary of this disclosure]
A summary of the present disclosure is added below.
A light source device according to a first aspect of the present disclosure is a light source device that emits illumination light, comprising: a first light source that emits blue light; a second light source that emits green light; and a wavelength conversion element that converts the wavelength of the blue light to generate fluorescence, wherein the illumination light includes a blue light component, a green light component and a red light component, and the blue light component is the first light source. The green light component includes green light emitted from the second light source, and the red light component includes red light having a wavelength of 590 nm or greater in the fluorescence.

According to such a configuration, of the illumination light emitted from the light source device, the blue light component includes the blue light emitted from the first light source, and the green light component includes the green light emitted from the second light source. including. According to this, the blue light component contained in the illumination light can be made into blue light with high purity, and the green light component contained in the illumination light can be made into green light with high purity. Further, since the red light component contained in the illumination light is red light having a wavelength of 590 nm or more, the red light component can also be red light with high purity. Therefore, each color light contained in the illumination light can be made into color light with high purity.

In the first aspect, the wavelength conversion element may contain a phosphor containing YGdAG and Ce as an activator.
Here, the peak wavelength of the fluorescence emitted from the wavelength conversion element containing the phosphor containing YGdAG (YGdAG phosphor) and Ce as an activator is determined by the phosphor containing YAG (YAG phosphor) and Ce. It is higher than the peak wavelength of fluorescence emitted from the contained wavelength conversion element. Therefore, when the amount of fluorescence emitted from the wavelength conversion element containing the YGdAG phosphor and the amount of fluorescence emitted from the wavelength conversion element containing the YAG phosphor are the same, the wavelength conversion element The amount of red light in emitted fluorescence can be increased.

In the first aspect, the wavelength conversion element may contain a phosphor containing La ₃ Si ₆ N ₁₁ and Ce as an activator.
According to such a configuration, the peak wavelength of the fluorescence emitted from the wavelength conversion element containing the phosphor containing La ₃ Si ₆ N ₁₁ (LSN phosphor) and the activator Ce is the same as that of the YAG phosphor. It is higher than the peak wavelength of fluorescence emitted from the wavelength conversion element containing Ce. Therefore, similarly to the wavelength conversion element containing the YGdAG phosphor, the amount of fluorescence emitted from the wavelength conversion element containing the LSN phosphor and the amount of fluorescence emitted from the wavelength conversion element containing the YAG phosphor are are the same, the amount of red light in the fluorescence emitted from the wavelength conversion element can be increased.

In the first aspect, the wavelength conversion element may contain a phosphor containing YAG and Cr, and Ce as an activator.
Here, the light amount of the red light component in the fluorescence emitted from the wavelength conversion element containing Ce and a phosphor containing YAG and Cr (Cr+YAG phosphor) is obtained from the wavelength conversion element containing YAG phosphor and Ce. It is larger than the light amount of the red light component in the emitted fluorescence. Therefore, similarly to the wavelength conversion element containing the YGdAG phosphor or the LSN phosphor, the amount of fluorescence emitted from the wavelength conversion element containing the Cr+YAG phosphor and the amount of light emitted from the wavelength conversion element containing the YAG phosphor When the light amount of the fluorescence emitted from the wavelength conversion element is the same, the light amount of the red light in the fluorescence emitted from the wavelength conversion element can be increased.

In the first aspect, the light combining member for outputting combined light obtained by combining the blue light emitted from the first light source and the green light emitted from the second light source; A diffusing element provided on a light incident side for diffusing incident light; and a reflecting element provided between the diffusing element and the wavelength conversion element for reflecting at least part of the incident green light. may
According to such a configuration, the green light emitted from the second light source and diffused by the diffusion element can be included in the illumination light emitted from the light source device. Therefore, green light with high purity can be included in the illumination light.

In the first aspect, the wavelength conversion element is provided on a wavelength conversion layer that converts blue light out of the combined light into the fluorescent light, and on the opposite side of the wavelength conversion layer to the blue light incident side, and the wavelength conversion element is provided on the side opposite to the wavelength conversion layer. and a reflective layer that reflects light, and the wavelength conversion layer may emit part of the blue light that is incident.
According to such a configuration, fluorescence generated by the wavelength conversion element can be incident on the diffusion element via the reflection element and diffused by the diffusion element. In addition, since the wavelength conversion layer emits part of the incident blue light, the blue light emitted from the wavelength conversion layer can enter the diffusion element via the reflection element and be diffused by the diffusion element. can. Therefore, the illuminance distribution of the illumination light emitted from the light source device can be made uniform.

In the first aspect, the light combining element is provided for combining the light emitted from the wavelength conversion element and the green light emitted from the second light source, and the wavelength conversion element is the blue light emitted from the first light source. a wavelength conversion layer that converts light into fluorescence; and a wavelength conversion layer that is provided between the first light source and the wavelength conversion layer, transmits blue light emitted from the first light source, and enters from the wavelength conversion layer. and a reflective layer that reflects fluorescence, and the wavelength conversion layer may emit the fluorescence and part of the blue light emitted from the first light source toward the photosynthesis element.
According to such a configuration, the blue light emitted from the first light source, the red light contained in the fluorescence, and the green light emitted from the second light source can be synthesized by the photosynthesis element and emitted. Therefore, illumination light containing highly pure colored light can be emitted from the light source device.

A projector according to a second aspect of the present disclosure includes the light source device according to the first aspect, a light modulation device that modulates light emitted from the light source device, and a projector that projects the light modulated by the light modulation device. and an optical device.
According to such a configuration, it is possible to obtain the same effect as that of the light source device according to the first aspect, thereby improving the color reproducibility of the projected image.

DESCRIPTION OF SYMBOLS 1... Projector 343 (343R, 343G, 343B)... Optical modulation apparatus 36... Projection optical apparatus 4, 5... Light source apparatus 41... First light source 411... First solid-state light emitting element 412... First light source support Substrate 413 First collimating lens 414 First afocal optical element 415 First lens 416 Second lens 42 Second light source 421 Second solid-state light emitting element 422 Second light source Support substrate 423 Second collimating lens 424 Second afocal optical element 425 First lens 426 Second lens 43 Light combining member 44 Angle conversion element 45 Reflecting member 451 Reflective part 452 Transmissive part 46 Condensing element 47 Diffusion element 471 Incident surface 472 Concave curved surface 473 Antireflection layer 48 Reflective element 49 Wavelength conversion element 491 Wavelength conversion Layer 492 Incident surface 493 Reflective layer 494 Substrate 5 Light source device 51 Wavelength conversion element 511 Wavelength conversion layer 512 Reflective layer 513 Substrate 52 First collimating element 53... Second light source, 54... Condensing element, 55... Diffusion device, 551... Diffusion element, 552... Driving element, 56... Second collimating element, 57... Photosynthesis element, 58... Reflecting element, BL... Blue light, FL... fluorescence, GL... green light, RL... red light, SL... synthetic light.

Claims (8)

A light source device that emits illumination light,
a first light source that emits blue light;
a second light source that emits green light;
a wavelength conversion element that converts the wavelength of blue light emitted from the first light source to generate fluorescence,
the illumination light includes a blue light component, a green light component and a red light component;
the blue light component includes blue light emitted from the first light source;
the green light component includes green light emitted from the second light source;
The light source device, wherein the red light component includes red light having a wavelength of 590 nm or more in the fluorescence. In the light source device according to claim 1,
The light source device, wherein the wavelength conversion element contains a phosphor containing YGdAG and Ce as an activator. In the light source device according to claim 1,
The light source device, wherein the wavelength conversion element contains a phosphor containing La ₃ Si ₆ N ₁₁ and Ce as an activator. In the light source device according to claim 1,
A light source device, wherein the wavelength conversion element contains a phosphor containing YAG and Cr, and Ce as an activator. In the light source device according to any one of claims 1 to 4,
a light synthesizing member that emits synthesized light obtained by synthesizing the blue light emitted from the first light source and the green light emitted from the second light source;
a diffusion element provided on the incident side of the combined light with respect to the wavelength conversion element and diffusing the incident light;
and a reflecting element provided between the diffusing element and the wavelength converting element for reflecting at least part of the incident green light. In the light source device according to claim 5,
The wavelength conversion element is
a wavelength conversion layer that converts blue light out of the combined light into the fluorescent light;
a reflective layer that is provided on the opposite side of the wavelength conversion layer from the blue light incident side and that reflects incident light;
The light source device, wherein the wavelength conversion layer emits part of the blue light that is incident thereon. In the light source device according to any one of claims 1 to 5,
a photosynthesis element that synthesizes the light emitted from the wavelength conversion element and the green light emitted from the second light source;
The wavelength conversion element is
a wavelength conversion layer that converts blue light emitted from the first light source into the fluorescence;
a reflective layer that is provided between the first light source and the wavelength conversion layer, transmits blue light emitted from the first light source, and reflects the fluorescence incident from the wavelength conversion layer;
The light source device, wherein the wavelength conversion layer emits the fluorescence and part of the blue light emitted from the first light source toward the photosynthesis element. a light source device according to any one of claims 1 to 7;
a light modulating device that modulates light emitted from the light source device;
and a projection optical device that projects the light modulated by the light modulation device.

Images