JP2015102864A - Light source device and projection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a color temperature of a projection image from being changed according to characteristics change of a light source.SOLUTION: A light splitting section splits light of a first color emitted from a light source into first and second light beams of the first color. A phosphor surface is excited by the second light beam to emit a third light beam of a fourth color including a second color component and a third color component. A dichroic mirror reflects the light of the first color and transmits the light of the fourth color. The dichroic mirror reflects the second light beam on a first surface and guides it to the phosphor surface, and transmits the light of the fourth color emitted from the phosphor surface from the first surface toward a second surface. A light diffusion section arranged between the light splitting section and the dichroic mirror diffuses the second light beam emitted from the light splitting section, and emits it toward the dichroic mirror.

Description

  The present invention relates to a light source device and a projection device for projecting a full-color projection image.

2. Description of the Related Art Conventionally, there has been known a projection apparatus that has a light source that emits light of each of RGB colors of the three primary colors, and that modulates the light of each RGB color emitted from each light source with an image signal of each RGB color and projects it onto a screen or the like. Yes. A projection apparatus having such RGB light sources can obtain a higher-quality projected image than a projection apparatus that converts white light into RGB light using a color filter and projects the light.

In recent years, it has been proposed to use an LED (Light Emitting Diode) or a laser element as the light source of the projection apparatus from the viewpoints of reduction of power consumption, consideration of environmental problems, the life of the light source itself, and the like. In Patent Document 1, a blue laser element that emits blue light to a light source and a plurality of LEDs that respectively emit blue light and green light, and a phosphor that emits red light when excited by blue light are disclosed. A projection apparatus provided is disclosed.

JP 2011-221504 A

However, if the three primary colors are used as individual light sources, the ratio of the light amounts of the three primary colors changes due to variations in the amount of light for each light source and variations in the amount of light from the light source over time, causing the color temperature of the projected image to fluctuate. was there. Also in Patent Document 1, since the blue and green light sources are used, the problem that the color temperature of the projected image fluctuates according to the change in the characteristics of the light source cannot be solved.

The present invention has been made in view of the above, and an object of the present invention is to make it possible to suppress variations in the color temperature of a projected image in accordance with changes in the characteristics of a light source.

In order to solve the above-described problems and achieve the object, the present invention provides light that divides light of a first color emitted from a light source into first light and second light of the first color. A splitting unit; a phosphor surface that emits third light of a fourth color including the second color component and the third color component when excited by the second light;
Is a dichroic mirror that reflects the light of the fourth color and transmits the light of the fourth color, reflects the second light on the first surface and guides it to the phosphor surface, and emits the fourth light emitted from the phosphor surface. The dichroic mirror that transmits light of the color from the first surface toward the second surface and the light splitting unit and the dichroic mirror are disposed to diffuse the second light emitted from the light splitting unit And a light diffusing unit that emits light toward the dichroic mirror.

According to the present invention, it is possible to suppress the variation in the color temperature of the projected image according to the change in the characteristics of the light source.

FIG. 1 is a diagram illustrating a configuration of an example of a light source device according to the first embodiment. FIG. 2 is a diagram for explaining the effect of the first diffusion plate according to the first embodiment. FIG. 3 is a diagram for describing a first modification of the first embodiment. FIG. 4 is a diagram illustrating an example of a light source device using a diffraction grating element according to a first modification of the first embodiment. FIG. 5 is a diagram for explaining a second modification of the first embodiment. FIG. 6 is a diagram illustrating an example of characteristics of the first dichroic mirror applicable to the second modification example of the first embodiment. FIG. 7 is a diagram illustrating an example of a light source device when a λ / 4 wavelength plate is added according to a second modification of the first embodiment. FIG. 8 is a diagram illustrating a configuration of an example of a main part of the light source device according to the second embodiment. FIG. 9 is a diagram illustrating an example of a configuration according to the first modification of the second embodiment. FIG. 10 is a diagram illustrating an example of a configuration according to the second modification of the second embodiment.

DESCRIPTION OF EMBODIMENTS Preferred embodiments of a light source device and a projection device according to the present invention will be described below with reference to the drawings. Specific numerical values and appearance configurations shown in the embodiments are merely examples for facilitating understanding of the present invention, and do not limit the present invention unless otherwise specified. Detailed explanation and illustration of elements not directly related to the present invention are omitted.

In each embodiment of the present invention, the first color light emitted from the light source is divided into the first light and the second light, respectively. The fourth color including the second color component and the third color component by reflecting the second light of the divided light and the light of the first color on each of the first surface and the second surface. Is guided to the first surface of the dichroic mirror that transmits at least from the first surface to the second surface. The second light reflected by the first surface of the dichroic mirror is applied to the phosphor surface that is excited by the first color light and emits the fourth color light. The third light of the fourth color emitted by being excited by the second light on the phosphor surface is emitted through the dichroic mirror from the first surface toward the second surface. The first light is guided to the second surface of the dichroic mirror through the relay optical system, reflected, and emitted together with the third light transmitted through the dichroic mirror.

Since the light source device according to each embodiment has the above-described configuration, it is possible to obtain light of three primary colors with one light source. Therefore, when the light source device according to each embodiment is used as the light source of the projection device, for example, it is possible to suppress the variation in the color temperature of the projected image when the characteristics of the light source change due to long-term use.

Furthermore, the light source device according to the first embodiment disperses the light irradiated on the phosphor surface so that the second light is diffused by the diffusion plate and guided to the dichroic mirror. Thereby, the reliability of the phosphor is improved and the excitation efficiency of the phosphor can be improved.

Further, in the light source device according to the second embodiment, the second surface is irradiated with the second light and the third surface is irradiated with the third light.
The optical path for obtaining the light and the relay optical path for the first light are respectively formed on the intersecting surfaces, and the optical system is configured in a three-dimensional manner. As a result, the light source device can be configured more compactly.

(First embodiment)
A configuration of the light source device according to the first embodiment will be described. FIG. 1 shows an example of the configuration of a light source device 1 according to the first embodiment. Hereinafter, as appropriate, blue light is described as B light, green light as G light, red light as R light, and yellow light as Y light.

In FIG. 1A, a light source 100 includes, for example, one or more blue laser elements, and emits light (B light) in a predetermined wavelength band that is visually recognized as blue. The light source 100 may be composed of a single blue laser element or a laser array in which a plurality of blue laser elements are arranged in an array. The B light emitted from the light source 100 passes through the condenser lens 101 and is divided into mirrors 1.
02 is incident.

The split mirror 102 splits the incident B light into first B light and second B light. That is, the split mirror 102 reflects a part of the incident B light as the first B light and transmits the remaining B light as the second B light. As the split mirror 102, for example, a derivative thin film mirror can be used. For example, a metal thin film, a reflective polarizing plate, or a dot beam splitter can be applied to the split mirror 102.

The second B light transmitted through the split mirror 102 is diffused through the first diffusion plate 103 and is incident on the first surface of the first dichroic mirror 104. This first dichroic mirror 1
04 and a second dichroic mirror 110, which will be described later, have characteristics of reflecting light in the wavelength band of B light and transmitting light in a wavelength band longer than the wavelength band of B light (for example, red light and green light). The second B light incident on the first dichroic mirror 104 is reflected by the first surface of the first dichroic mirror 104 and is rotated by the motor 202 via the condenser lenses 105 and 106. Is incident on.

FIG. 1B shows an exemplary configuration of the phosphor wheel 200. The phosphor wheel 200 is
A phosphor surface 201 is formed concentrically on the mirror-like surface. The phosphor surface 201 is coated with a phosphor that is excited by light in the wavelength band of B light and emits yellow light (Y light). In addition, since yellow is obtained by mixing green and red in the additive color method, the yellow light emitted from the phosphor surface 201 includes a red component and a green component.

Here, the second B light is diffused through the first diffusion plate 103 and then irradiated onto the phosphor surface 201. Thereby, the second B light is dispersed and irradiated on the phosphor surface 201, damage to the phosphor surface 201 by the B light is suppressed, and the reliability of the phosphor is improved. In addition, the phosphor has a characteristic that when the light density of the irradiated light exceeds a certain value, the excitation efficiency decreases due to heat generation or the like. By diffusing the second B light by the first diffusion plate 103, the light density of the second B light applied to the phosphor is lowered, and the excitation efficiency of the phosphor can be increased.

The effect of the first diffusion plate 103 according to the first embodiment will be described more specifically with reference to FIG. In FIG. 2, the same reference numerals are given to portions common to FIG. 1, and detailed description is omitted. In FIG. 2, the split mirror 102 and the first dichroic mirror 1 in FIG.
04 and the condensing lens 106 are omitted.

The light source 100 includes a plurality of blue laser elements and emits a plurality of laser beams. The plurality of laser beams are respectively diffused by the first diffusion plate 103, converted into incident light having continuously changed incident angles, and incident on the condenser lens 105. In the condenser lens 105, the incident light is refracted according to the incident angle and emitted. Therefore, the phosphor surface 201 is irradiated with the laser light emitted from the light source 100 as light having a substantially uniform light density.

The Y light emitted from the phosphor surface 101 passes through the first dichroic mirror 104, and the second light
The light is emitted from the surface and is incident on the first surface of the second dichroic mirror 110. As described above, the second dichroic mirror 110 has a characteristic of transmitting Y light. Therefore, the Y light is emitted from the second surface of the second dichroic mirror 110 as the Y light.

On the other hand, the first B light emitted from the split mirror 102 enters the mirror 108 via the lens 136 and the second diffusion plate 107. The second diffusion plate 107 is used for diffusing the first B light and aligning the thickness of the light beam with that of the Y light. In the light source device 1, the second diffusion plate 107 is not an essential configuration. The direction of the first B light is changed by the mirror 108 and is incident on the second surface of the second dichroic mirror 110 via the lens 109. As described above, the second dichroic mirror 110 has a characteristic of reflecting B light. Therefore, the first
The B light is reflected by the second surface of the second dichroic mirror 110, changed in direction, and emitted. The first B light is emitted in the same direction as the Y light transmitted through the second dichroic mirror 110 described above.

As described above, the lens 136, the second diffusing plate 107, the mirror 108, and the lens 109 constitute a relay optical system that guides the first B light to the second dichroic mirror 110.

Hereinafter, the first B light emitted from the second dichroic mirror 110 is simply referred to as B light.

The Y light and B light emitted from the second dichroic mirror 110 are reflected by the mirror 111 and changed in direction. Depending on the layout of the light source device 1, this mirror 111 is used.
Can be omitted.

Y light and B light emitted from the mirror 111 are fly-eye lenses 112 and 113.
Through the lens 114. When the fly-eye lenses 112 and 113 irradiate each light modulation element 119, 125, and 128, which will be described later, with each light based on Y light and B light, each light is uniformly applied to each light modulation element 119, 125, and 128. A uniform illumination optical system that disperses the light so as to be irradiated is formed.

The Y light and the B light are emitted from the lens 114, and the light separator 11 that separates the B light and the Y light.
5 is incident. For example, the light separator 115 reflects the light in the wavelength band of B light and transmits the light in the wavelength band of Y light, and reflects the light in the wavelength band of Y light and reflects the light in the wavelength band of B light. And a second dichroic mirror that transmits light. The B light separated by the light separator 115 is emitted from the light separator 115 and is incident on the mirror 116. The Y light separated by the light separator 115 is emitted from the light separator 115 and is incident on the mirror 121.

The B light incident on the mirror 116 is incident on the reflective polarizing plate 118 via the lens 117. The reflective polarizing plate 118 transmits one of the S-polarized light and the P-polarized light and reflects the other polarized light. Here, B light emitted from the lens 117 is S-polarized light, light reflected by a light modulation element 119 described later is P-polarized light, the reflective polarizing plate 118 transmits S-polarized light, and P-polarized light is reflected. It shall have the property of reflecting.

The B light transmitted through the reflective polarizing plate 118 enters the light modulation element 119. Light modulation element 1
19 is driven in accordance with the B color image signal, and modulates and reflects the incident light for each pixel and emits it. As the light modulation element 119, for example, a reflective liquid crystal element can be applied. An element applicable to the light modulation element 119 is not limited to the reflective liquid crystal element. For example, DMD (Dig
Ital Mirror Device) can also be applied to the light modulation element 119.

The B light modulated for each pixel in accordance with the B color image signal by the light modulation element 119 is reflected by the reflective polarizing plate 118, changed in direction, and emitted to the light combining prism 120 from the first surface. Is done.

The Y light separated by the light separator 115 and incident on the mirror 121 is reflected by the mirror 121, changed in direction, and emitted from the mirror 121. The Y light emitted from the mirror 121 enters the color component separator 122, and the green light component and the red light component are separated from the Y light. For example, the color component separator 122 is configured using a dichroic mirror that reflects light in the green wavelength band and transmits light in the red wavelength band.

Green component light (green light, hereinafter referred to as G light) separated from the Y light by the color component separator 122 is incident on the reflective polarizing plate 124 via the lens 123. Similarly to the B light described above, the G light is assumed to be S-polarized light, and the G light is transmitted through the reflective polarizing plate 124 and is incident on the light modulation element 125 driven according to the G color image signal. The light modulation element 125 modulates and reflects the incident G light for each pixel according to the G color image signal and emits it. The G light emitted from the light modulation element 125 is reflected by the reflective polarizing plate 124 and is incident on the light combining prism 120 from the second surface.

The red component light (red light, hereinafter referred to as R light) separated from the Y light by the color component separator 122 is incident on the reflective polarizing plate 127 via the lens 126. Similarly to the B light described above, the R light is assumed to be S-polarized light, and the R light is transmitted through the reflective polarizing plate 127 and is incident on the light modulation element 128 driven according to the R color image signal. The light modulation element 128 modulates and reflects the incident R light for each pixel in accordance with the R color image signal and emits it. The R light emitted from the light modulation element 128 is reflected by the reflective polarizing plate 127 and enters the light combining prism 120 from the third surface.

The light combining prism 120 combines the B light, G light, and R light incident from the first surface, the second surface, and the third surface, respectively, and emits the light from the fourth surface as a bundle of light beams. A light beam including R light, G light, and B light emitted from the light combining prism 120 is projected onto the projection optical system 12.
Injected to the outside through 9.

As described above, the light source device 1 according to the first embodiment uses one light source 100 to generate R light, G
Light and B light are generated. Therefore, even if the characteristics of the light source 100 change with time, the light source device 1 does not change the balance of the R light, the G light, and the B light, and suppresses the variation in the color temperature of the projection light. be able to.

Further, the light source device 1 according to the first embodiment disperses the light irradiated on the phosphor surface 201 by diffusing the second B light by the first diffusion plate 103 and guiding it to the first dichroic mirror 104. doing. Thereby, the reliability of the phosphor is improved and the excitation efficiency of the phosphor can be improved.

Here, in the light source device 1 according to the first embodiment, means for dividing the B light emitted from the light source 100 (dividing mirror 102) and means for irradiating the phosphor surface 201 with the B light (first dichroic mirror). 104) are provided separately. A first diffusion plate 103 that diffuses B light is disposed between the split mirror 102 and the first dichroic mirror 104. Therefore, the B light irradiated on the phosphor surface 201 and the Y emitted from the phosphor surface 201
Among the light, B light for irradiating the phosphor surface 201 with the first diffusion plate 103 can be selectively applied.

The means for dividing the B light emitted from the light source and the means for irradiating the phosphor surface with the B light can be configured in common by one dichroic mirror or the like, so that the number of parts can be reduced. However, in this case, the diffusion plate for diffusing the B light irradiated on the phosphor surface is the 1
Therefore, the Y light emitted from the phosphor surface is also diffused.

Note that the phosphor wheel 200 or the condenser lens 106 is added to the configuration shown in FIG.
In addition, it is preferable to provide a position adjustment mechanism in each of 105 and 105 because the excitation efficiency on the phosphor surface 201 can be further improved. Moreover, it is desirable that each lens used in the light source device 1 satisfies the Herschel condition.

Further, the first dichroic mirror 104 and the second dichroic mirror 110 are
The blue reflection and yellow transmission types used in the light source device 1 described above are more efficient and preferable than the yellow reflection and blue transmission types.

Furthermore, when a mirror of a type using a metal thin film is applied to the split mirror 102 that splits the B light from the light source 100, the position of the split is adjusted by adjusting the position of the metal thin film having different transmission / reflection characteristics depending on the location It is possible to change. Further, when a reflective polarizing plate is used as the split mirror 102, it is possible to adjust the split ratio by adjusting the transmission / reflection characteristics by in-plane rotation adjustment.

(First modification of the first embodiment)
Next, a first modification of the first embodiment will be described. In the first modification of the first embodiment, as the first diffusion plate 103 that diffuses the B light irradiated on the phosphor surface 201, the light is diffused so as to spread within a predetermined range, and the light intensity distribution is changed. An intensity uniformizing element that uniformizes within a predetermined range is used. A first modification of the first embodiment will be described with reference to FIG.

FIG. 3A schematically shows a configuration of an example of an optical system according to the first modification of the first embodiment. Laser light emitted from a light source 300 including a plurality of blue laser elements is converted into a lens 301.
Is incident on the intensity equalizing element 310 according to the first modification, and the intensity equalizing element 3
The laser beam emitted from 10 is irradiated on the phosphor surface 304 as blue B light through the lens 303.

The phosphor surface 304 emits Y light when excited by the irradiated B light. As for this Y light, for example, R light is separated through a light component separation unit (not shown) and the like, and is incident on the illumination optical system 305. The illumination optical system 305 includes a plurality of lenses 320 and 322 and a light pipe 321. The R light incident on the illumination optical system 305 enters the light pipe 321 via the incident side lens 320. The light pipe 321 scatters the incident R light on the inner wall and emits it with uniform light intensity on the exit surface. The R light emitted from the light pipe 321 is emitted from the illumination optical system 305 through the lens 322 on the emission side, and is applied to the light modulation element 306 driven for each pixel in accordance with the R color image signal.

By using the light pipe 321, the light intensity in the pixel region of the light irradiated to the light modulation element 306 is made uniform, and a good projection image can be obtained.

In the first modification, a diffraction grating in which a diffraction pattern is set so that incident light is emitted with a substantially rectangular angular distribution is used as the intensity uniformizing element 310. As such a diffraction grating, homogenizers (Homogenizers) manufactured by Holo / Or Ltd (Israel) can be applied. By using this diffraction grating element, the light intensity distribution can be shaped into a rectangular shape.

FIG. 3B shows the case where the intensity equalizing element 310 is not used, the case where a diffusion plate is used as the intensity equalizing element 310, and the case where the intensity equalizing element 310 is described above at the predetermined position in FIG. It is the figure which compared distribution of light intensity by the case where a diffraction grating element is used.

When compared at the position of the phosphor surface 304, the light intensity distribution 400 when the intensity uniformizing element 310 is not used protrudes at the center of the phosphor surface 304, for example. On the other hand, in the case where a diffusion plate and a diffraction grating element are used as the intensity uniformizing element 310, it can be seen that they are dispersed with respect to the phosphor surface 304 as shown in the light intensity distributions 401 and 402, respectively. . In particular, when a diffraction grating element is used as the intensity uniformizing element 310, as exemplified by the light intensity distribution 402, the light intensity is made uniform to a value within a predetermined range, and is substantially 0 in other ranges.
Can be controlled.

Further, at the entrance portion of the light pipe 321, when the intensity equalizing element 310 is not used, as illustrated in the light intensity distribution 400 ′, the light pipe 321 is concentrated in a very narrow range with respect to the opening diameter r. It has been done. In this case, the degree of light scattering in the light pipe 321 is considered to be low, and it is predicted that the intensity distribution on the exit surface will not be uniform. Further, when a diffusion plate is used as the intensity uniformizing element 310, the light intensity distribution 40 is obtained.
As exemplified by 1 ′, the intensity distribution protrudes with respect to the opening diameter r of the light pipe 321. This means that the light emitted toward the light pipe 321 cannot be used effectively.

On the other hand, when the above-described diffraction grating element is used as the intensity uniformizing element 310, the range of the intensity distribution of the light incident on the light pipe 321 is changed as shown in the light intensity distribution 402 ′. It is possible to control the range according to the opening diameter r. Therefore, the light emitted toward the light pipe 321 can be used effectively, and the light pipe 321 is sufficiently scattered to obtain extremely uniform emitted light on the exit surface.

FIG. 4 shows an example of a light source device in the case where the above-described diffraction grating element is used as the intensity uniformizing element 310 according to a first modification of the first embodiment. In FIG. 4, the same reference numerals are given to portions common to FIG. 1 described above, and detailed description thereof is omitted.

In FIG. 4, the light source device 1 a arranges the diffraction grating element 150 between the split mirror 102 and the first dichroic mirror 104 instead of the first diffusion plate 103 of FIG. 1. In the light source device 1a, the illumination optical systems 151, 152, and 153 including the above-described lenses 320 and 322 and the light pipe 321 are disposed at the positions of the lenses 117, 123, and 126 in FIG. By adopting such a configuration, it is possible to improve the uniformity of the B light, G light, and R light applied to each of the light modulation elements 119, 125, and 128, and when the light source device 1a is applied to a projection device. Therefore, it is possible to obtain a projected image with higher image quality.

In FIG. 4, the condenser lens 105 has been described as being a normal lens, but this is not limited to this example. For example, the condensing lens 105 may be a diffractive lens that has a condensing function by changing the diffraction pitch in the plane. The same applies to the condenser lens 106. In this case, the diffraction grating element 150 and the condensing lens 105 can be configured integrally.

(Second modification of the first embodiment)
Next, a second modification of the first embodiment will be described. In the second modification of the first embodiment, the light emitted from the light source 100 is effectively used by polarizing the light emitted to the phosphor surface 201 and the light emitted from the phosphor surface 201. ing. A second modification of the first embodiment will be described with reference to FIG.

FIG. 5 (c) shows a legend of symbols used in FIGS. 5 (a) and 5 (b). That is, “● (black circle)” indicates S-polarized linearly polarized light, up and down arrows indicate P-polarized linearly polarized light, arc-shaped arrows indicate circularly polarized light, and “●” with an up and down arrow is a symbol Random polarization is shown. 5 (a) and 5 (b), the same reference numerals are given to the portions common to FIG. 1 described above, and detailed description thereof is omitted. 5A and 5B, the condensing lens 101 and the split mirror 102 are omitted.

FIG. 5A schematically shows an example in which the second modification is not applied. The B light emitted from the light source 100 and reflected by the first dichroic mirror 104 is applied to the phosphor surface 201 via the condenser lenses 105 and 106 according to the optical path 1001, for example. Phosphor surface 20
The Y light that is excited by the B light in 1 and emitted is transmitted through the first dichroic mirror 104 along the optical path 1002 and emitted.

Here, the B light emitted from the light source 100 is first diffused after being diffused by a diffusion plate (not shown).
The light is reflected by the dichroic mirror 104 and applied to the phosphor surface 201. Therefore, there is a possibility that the B light is irradiated not only on the phosphor surface 201 but also on a position other than the phosphor surface 201 on the phosphor wheel 200. In this case, since the phosphor wheel 200 has a mirror-like surface, the B light irradiated to a position other than the phosphor surface 201 is the phosphor wheel 20.
The light is reflected by the zero mirror portion and travels toward the first dichroic mirror 104. In addition, even when the phosphor surface 201 is irradiated, there is also B light that is reflected by the phosphor surface 201 without exciting the phosphor. The B light reflected by the phosphor wheel 200 without contributing to the excitation of the phosphor is reflected by the first dichroic mirror 104 as indicated by the optical path 1004. Therefore, the B light reflected as in the optical path 1004 does not contribute to the final projection light.

FIG. 5B schematically shows an example of a configuration according to the second modification. In the second modification,
As illustrated in FIG. 5B, the first dichroic mirror 104 ′ and the condenser lens 105 are used.
A λ / 4 wave plate 160 is disposed between the two. The λ / 4 wavelength plate 160 converts circularly polarized light and linearly polarized light passing through each other. By passing through the λ / 4 wavelength plate 160 twice, the polarization direction of the linearly polarized light can be changed between P-polarized light and S-polarized light.

FIG. 6 shows an example of characteristics of the first dichroic mirror 104 ′ applicable to the second modification. The first dichroic mirror 104 ′ has different transmittance characteristics between P-polarized light and S-polarized light. The first dichroic mirror 104 ′ has a low transmittance T for light having a shorter wavelength than the lower limit of the wavelength band of the blue laser light emitted from the light source 100. On the other hand, for S-polarized light, the transmittance T is higher for light having a longer wavelength than the upper limit of the wavelength band of blue laser light. In other words, the first dichroic mirror 104 ′ transmits blue laser light with P-polarized light, but S
Reflected with polarized light.

In the second modification, this characteristic of the first dichroic mirror 104 ′ and the above-described λ /
Using the four-wave plate 160, the B light reflected by the mirror portion of the phosphor wheel 200 is effectively utilized.

Referring to FIG. 5B, it is assumed that the B light emitted from the light source 100 is linearly polarized light / S polarized light. This B light is reflected by the first dichroic mirror 104 ′ according to the description of FIG. 6, passes through the λ / 4 wavelength plate 160, and is converted into circularly polarized light. When this circularly polarized B light is reflected by the phosphor wheel 200 and passes through the λ / 4 wavelength plate 160 again, it is converted into linearly polarized light. At this time, the B light is equivalent to having passed through the λ / 4 wavelength plate 160 twice, and S-polarized light emitted from the light source 100 is converted to P-polarized light, and the first dichroic mirror 104 follows the optical path 1012. 'Injected from. According to the description of FIG. 6, the P-polarized B light can pass through the first dichroic mirror 104 ′.

FIG. 7 shows an example of a light source device when a λ / 4 wavelength plate is added according to the configuration shown in FIG. In FIG. 7, the same reference numerals are given to the same parts as those in FIG. 1 described above, and detailed description thereof is omitted.

In FIG. 7, the light source device 1b is a first dichroic mirror 1 according to the example of FIG.
A λ / 4 wavelength plate 160 is disposed between 04 ′ and the condenser lens 105. As described with reference to FIG. 5B, the B light reflected by the phosphor wheel 200 is converted to P-polarized light by the λ / 4 wavelength plate 160 and passes through the first dichroic mirror 104 ′. The B light transmitted through the first dichroic mirror 104 ′ is incident on the second dichroic mirror 110 ′.

Here, the characteristics of the second dichroic mirror 110 ′ are represented by the first dichroic mirror 10.
If the characteristics are the same as those of 4 ′, the B light transmitted through the first dichroic mirror 104 ′ and incident on the second dichroic mirror 110 ′ is transmitted through the second dichroic mirror 110 ′ and emitted. Accordingly, the B light coming from the first dichroic mirror 104 ′ is emitted from the second dichroic mirror 110 ′ together with the first B light reflected by the mirror 108 and incident on the second dichroic mirror 110 ′.

As described above, in the second modification, the B light reflected without contributing to excitation in the phosphor wheel 200 can be effectively used, and when the light source device 1b is applied to the projection device,
A higher quality projected image can be obtained.

(Second Embodiment)
Next, a second embodiment will be described. In the first embodiment described above, the first optical path for irradiating the phosphor wheel 200 with the B light from the light source 100 via the first dichroic mirror 104, and the first dichroic mirror 104 and the phosphor wheel with the B light. 200
The second optical path by the relay optical system that bypasses without involving the above is configured on the same plane or a plane parallel to one plane. In contrast, in the second embodiment, the first
The second optical path and the second optical path are configured in two planes that intersect each other.

FIG. 8 shows a configuration of an example of a main part of the light source device according to the second embodiment. 8A is a front view of the main part, and FIG. 8B is a side view of the configuration of FIG. 8A viewed from the direction of the arrow “A”. Hereinafter, unless otherwise specified, FIG. 8 (a) and FIG. 8 (b) are collectively shown in FIG.
Will be described.

The configuration in FIG. 8 corresponds to the configuration from the light source 100 to the second dichroic mirror 110 in the configuration of the light source device 1 in FIG. 1 described above. Since the configuration from the mirror 111 to the projection optical system 129 in FIG. 1 can be applied to the second embodiment as it is, description thereof is omitted here.

In FIG. 8, the B light emitted from the light source 500 including one or more blue laser elements is incident on the split mirror 502 via the condenser lens 501. The split mirror 502 corresponds to the split mirror 102 described above, and splits the incident B light into first B light and second B light. Hereinafter, for easy identification in the drawings, the first B light is described as B ₁ light and the second B light is described as B ₂ light.

The B ₂ light reflected and split by the split mirror 502 is incident on the second surface of the dichroic mirror 505 via a relay optical system including the lens 503, the mirror 504, the mirror 506, the lens 507, and the mirror 508. . The optical path on the relay optical system is configured on the first plane. Not limited to this, the optical path on the relay optical system may be configured on the first plane and on another plane parallel to the first plane.

The dichroic mirror 505 corresponds to the first dichroic mirror described above, reflects light in the wavelength band of B light, and light in a wavelength band longer than the wavelength band of B light (for example, red light or green light). It has the property of transmitting light.

On the other hand, the B ₁ light transmitted through the split mirror 502 and split is dichroic mirror 505.
Is incident on the first surface.

Here, in the second embodiment, the dichroic mirror 505 converts the incident light into the first
It is provided so as to reflect in a direction intersecting with the plane. In the example of FIG. 8A, the dichroic mirror 505 reflects the reflected light from the front side of FIG. 8A that reflects the B ₁ light that is emitted from the light source 500, transmitted through the split mirror 502, and split. It is provided so as to proceed along the optical path toward the side. That is, the optical path by the light reflected by the dichroic mirror 505 is
It is comprised on the 2nd plane which mutually cross | intersects with respect to a 1st plane.

The B ₁ light reflected by the dichroic mirror 505 is incident on the phosphor wheel 600 via the condenser lenses 509 and 510. The phosphor wheel 600 corresponds to the phosphor wheel 200 described above. A phosphor surface 601 is formed concentrically on a mirror-like surface and is driven to rotate by a motor 602. The phosphor surface 601 is coated with a phosphor that emits yellow light (Y light) by being excited by light in the wavelength band of B light in the same manner as the phosphor surface 201 described above.

A diffusion plate can be disposed between the split mirror 502 and the dichroic mirror 505. As a result, as described in the first embodiment, B on the phosphor surface 601
₁ light is dispersed and irradiated, damage to the phosphor is suppressed, the reliability of the phosphor is improved, and the excitation efficiency of the phosphor can be increased.

The Y light emitted from the phosphor surface 601 is incident on the first surface of the dichroic mirror 505 via the condenser lenses 510 and 509. The Y light passes through the dichroic mirror 505 and is emitted from the second surface of the dichroic mirror 505. In the example of FIG.
At the position of the dichroic mirror 505, Y light is emitted from the back side toward the front side.

Here, as described above, B ₂ light is incident on the second surface of the dichroic mirror 505 via the relay optical system. The B ₂ light is reflected by the second surface of the dichroic mirror 505 and is emitted in the same direction as the Y light. That is, the direction of the optical path of B ₂ light is changed by the dichroic mirror 505 from the optical path on the first plane to the optical path on the second plane.

The Y light and B ₂ light emitted from the dichroic mirror 505 in this way follow the optical path after the mirror 111 in FIG. 1, for example, and the Y light is separated into R light and G light so that R, G, B
Light of each color is formed. The light of each RGB color is modulated by a light modulation element driven by an image signal of each RGB color, and emitted from the projection optical system.

Thus, also in the second embodiment, one light source 5 is provided, as in the first embodiment.
00 is used to generate R light, G light and B light. Therefore, in the light source device to which the second embodiment is applied, the balance of the R light, the G light, and the B light does not change even when the characteristics of the light source 500 change with time, for example. Variation in color temperature can be suppressed.

In the second embodiment, the first optical path for irradiating the phosphor wheel 600 with the B light from the light source 500 via the dichroic mirror 505 and the dichroic mirror 505 and the phosphor wheel 600 are involved. 2nd relay optical system that bypasses
The three-dimensional structure is formed in each of two planes that intersect each other. Therefore, only one dichroic mirror is required, and a more compact configuration is possible. In addition, by enabling a three-dimensional structure, the degree of freedom of layout of each component increases, and this also enables a more compact configuration.

In the above description, the dichroic mirror 505 reflects the B ₁ light in a direction perpendicular to the surface of the optical path by the relay optical system, but this is not limited to this example. That is, the dichroic mirror 505 can be arranged to reflect the B ₁ light at other angles.

(First Modification of Second Embodiment)
Next, a first modification of the second embodiment will be described. Also in the configuration of the second embodiment, B ₁ irradiated to the phosphor surface 601 is the same as the first modification of the first embodiment described above.
In order to diffuse light, a diffraction grating element can be arranged as an intensity uniformizing element.

FIG. 9 shows an example of a configuration according to the first modification of the second embodiment. FIG. 9 shows an example in which a diffraction grating element is arranged with respect to the configuration of the second embodiment. Note that, in FIG. 9, the same reference numerals are given to portions common to FIG. 8 described above, and detailed description thereof is omitted. 9A is a front view, and FIG. 9B is a side view as seen from the direction indicated by the arrow A in FIG. 9A.

As illustrated in FIG. 9, a diffraction grating element 550 having characteristics equivalent to those of the above-described diffraction grating element 150 is disposed between the split mirror 502 and the dichroic mirror 505. Also,
Although illustration is omitted, illumination optical systems 151, 152, and 153 are arranged in the optical paths of the R light, G light, and B light toward the light modulation elements in the same manner as in FIG.

As a result, even in the configuration of the second embodiment, the B that irradiates the light modulation elements of the respective RGB colors
The uniformity of light, G light, and R light can be improved, and when the light source device according to the second embodiment is applied to a projection device, a higher quality projection image can be obtained.

(Second modification of the second embodiment)
Next, a second modification of the second embodiment will be described. Also in the configuration of the second embodiment, similarly to the second modification of the first embodiment described above, the light emitted from the phosphor surface 601 and the light emitted from the phosphor surface 601 are polarized, and the light source 500 It is possible to employ a configuration that makes effective use of the B light emitted from.

FIG. 10 shows an example of a configuration according to the second modification of the second embodiment. This FIG. 10 shows the second
This is an example in which a λ / 4 wavelength plate is arranged with respect to the configuration of the embodiment. In FIG. 10, the same reference numerals are given to the portions common to FIG. 8 described above, and detailed description thereof is omitted. Also, FIG.
(A) is a front view, FIG.10 (b) shows the side view seen from the direction shown by arrow A in Fig.10 (a).

As illustrated in FIG. 10, the λ / 4 wavelength plate 560 is disposed between the dichroic mirror 505 ′ and the condenser lens 509. The dichroic mirror 505 ′ has the characteristics described with reference to FIG. The light source 500 emits S-polarized blue laser light.

In this configuration, as in the second modification of the first embodiment, the B ₁ light split by the split mirror 502 and reflected by the dichroic mirror 505 ′ is converted to circularly polarized light by the λ / 4 wavelength plate 560. And enters the phosphor wheel 600. The B ₁ light reflected by the phosphor wheel 600 without contributing to the excitation of the phosphor passes again through the λ / 4 wavelength plate 560, and at that time, the polarized light is converted into P-polarized light. The B ₁ light converted into the P-polarized light is converted into the dichroic mirror 50.
5 is emitted in the same direction as the Y light emitted by the excitation of the phosphor.

As described above, also in the second modification of the second embodiment, the B light reflected without contributing to excitation in the phosphor wheel 600 can be used effectively, and the second embodiment of the second embodiment can be used. 2
When the light source device according to the modified example is applied to a projection device, a higher quality projection image can be obtained.

1, 1a, 1b Light source device 100, 300, 500 Light source 101, 105, 106, 501 Condensing lens 102, 502 Split mirror 103 First diffuser plate 104, 104 ′ First dichroic mirror 107 Second diffuser plate 108, 111, 116, 121, 504, 506, 508 Mirrors 109, 114, 117, 123, 126, 301, 303, 320, 322, 503
507 Lens 110, 110 ′ Second dichroic mirror 112, 113 Fly eye lens 115 Light separator 118, 124, 127 Reflective polarizing plate 119, 125, 128, 306 Light modulator 120 Light combining prism 122 Color component separator 129 Projection optics System 150, 550 Diffraction grating element 151, 152, 153 Illumination optical system 160, 560 λ / 4 wavelength plate 200, 600 Phosphor wheel 201, 304, 601 Phosphor surface 310 Intensity equalizing element 321 Light pipe 505, 505 ′ Dichroic mirror

Claims (3)

A light dividing unit that divides light of the first color emitted from the light source into first light and second light of the first color;
A phosphor surface that is excited by the second light and emits third light of a fourth color including a second color component and a third color component;
A dichroic mirror that reflects the light of the first color and transmits the light of the fourth color, reflects the second light on the first surface and guides it to the phosphor surface, and A dichroic mirror that transmits the light of the fourth color emitted from the body surface from the first surface toward the second surface;
A light diffusing unit that is disposed between the light dividing unit and the dichroic mirror, diffuses the second light emitted from the light dividing unit, and emits the light toward the dichroic mirror;
A λ / 4 wave plate disposed between the dichroic mirror and the phosphor surface;
Have
The second light emitted from the light splitting unit is S-polarized light,
The dichroic mirror is
A light source device that reflects the S-polarized light of the first color and further transmits the P-polarized light of the first color. The first color is blue;
The phosphor surface is
The light source device according to claim 1, wherein the light source device emits yellow light when excited by blue light. The light source device according to claim 1 or 2,
A light separation unit that separates the third light transmitted from the dichroic mirror into a fourth light of the second color component and a fifth light of the third color component;
A first light modulation element that modulates the first light in accordance with a first image signal corresponding to the first color;
A second light modulation element that modulates the fourth light in accordance with a second image signal corresponding to the second color;
A third light modulation element for modulating the fifth light in accordance with a third image signal corresponding to the third color;
The first light modulated by the first light modulation element, the fourth light modulated by the second light modulation element, and the fifth light modulated by the third light modulation element And a projection optical system that guides and emits the light in the direction of 1.

Images