JP2021156998A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device and a projector capable of generating bright illumination light having a desired white balance. A light source device of the present invention has a first light source that emits first light, an excitation light source that emits excitation light, and a second light source having a wavelength conversion unit that generates fluorescence, and a first light source. It is provided with a polarization separation / synthesis unit in which the first light emitted from the light source and the fluorescence emitted from the second light source are incident, and the polarization separation / synthesis unit uses the first light emitted from the first light source as the second light. Separated from the third light, the second light is incident on the wavelength conversion unit of the second light source, and the second light source fluoresces by converting the excitation light from the excitation light source and the second light into wavelength in the wavelength conversion unit. Is generated, and the polarization separation / synthesizing unit synthesizes the fluorescence and the third light to generate the illumination light. [Selection diagram] Fig. 2

Description

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

Conventionally, as a light source device used in a projector, fluorescence generated by exciting a phosphor and blue light emitted from a solid light source are combined to generate white illumination light (for example, the following). See Patent Document 1).

Japanese Patent Application Laid-Open No. 2014-507055

In the above light source device, the output of fluorescence generated by the phosphor is lower than the output of blue light emitted from a solid light source. Therefore, for example, when obtaining illumination light having a desired white balance, it is necessary to suppress the output of blue light in accordance with the output of fluorescence, and there is a problem that the brightness of the illumination light is lowered.

In order to solve the above problems, according to the first aspect of the present invention, a first light source that emits first light, an excitation light source that emits excitation light, and a wavelength conversion unit that generates fluorescence are provided. A second light source having a second light source, and a polarization separation / synthesis unit in which the first light emitted from the first light source and the fluorescence emitted from the second light source are incident are provided, and the polarization separation / synthesis unit includes the polarization separation / synthesis unit. The first light emitted from the first light source is separated into a second light and a third light, the second light is incident on the wavelength conversion unit of the second light source, and the second light source is the same. The excitation light from the excitation light source and the second light are wavelength-converted in the wavelength conversion unit to generate the fluorescence, and the polarization separation / synthesis unit synthesizes the fluorescence and the third light to illuminate the light. A light source device is provided, which comprises producing.

According to the second aspect of the present invention, the light source device of the first aspect of the present invention, the light modulation device that modulates the light from the light source device according to the image information, and the light modulated by the light modulation device are used. Provided is a projector characterized by comprising a projection optical device for projecting.

It is a figure which shows the structure of the projector of 1st Embodiment. It is a figure which shows the schematic structure of the light source apparatus of 1st Embodiment. It is a figure which shows the transmission characteristic of the dichroic mirror of the 1st Embodiment. It is a figure which shows the schematic structure of the light source apparatus of 2nd Embodiment. It is a figure which shows the transmission characteristic of the dichroic mirror of the 2nd Embodiment. It is a figure which shows the schematic structure of the light source apparatus of 3rd Embodiment. It is a figure which shows the transmission characteristic of the dichroic mirror of the 3rd Embodiment. It is a figure which shows the schematic structure of the projector of 4th Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The projector of this embodiment is an example of a projector using a liquid crystal panel as an optical modulation device.
In each of the following drawings, in order to make each component easy to see, the scale of dimensions may be different depending on the component.

(First Embodiment)
FIG. 1 is a diagram showing a configuration of a projector according to the present embodiment.
The projector 1 of the present embodiment shown in FIG. 1 is a projection type image display device that displays a color image on a screen (projected surface) SCR. The projector 1 uses three light modulators corresponding to each color light of red illumination light LR, green illumination light LG, and blue illumination light LB.

The projector 1 includes a light source device 2, a color separation optical system 3, a light modulation device 4R, a light modulation device 4G, a light modulation device 4B, a composite optical system 5, and a projection optical device 6. ..

The color separation optical system 3 includes a first dichroic mirror 7a, a second dichroic mirror 7b, a first reflection mirror 8a, a second reflection mirror 8b, a third reflection mirror 8c, and a first relay lens 9a. And a second relay lens 9b.

The first dichroic mirror 7a separates the white illumination light WL from the light source device 2 into the red illumination light LR and the other lights, the green illumination light LG and the blue illumination light LB. The first dichroic mirror 7a transmits the separated red illumination light LR and reflects other lights such as the green illumination light LG and the blue illumination light LB. On the other hand, the second dichroic mirror 7b reflects the green illumination light LG and transmits the blue illumination light LB to separate other light into the green illumination light LG and the blue illumination light LB.

The first reflection mirror 8a is arranged in the optical path of the red illumination light LR, and reflects the red illumination light LR transmitted through the first dichroic mirror 7a toward the light modulator 4R. On the other hand, the second reflection mirror 8b and the third reflection mirror 8c are arranged in the optical path of the blue illumination light LB, and guide the blue illumination light LB transmitted through the second dichroic mirror 7b to the light modulator 4B. The green illumination light LG is reflected from the second dichroic mirror 7b toward the light modulator 4G.

The first relay lens 9a is arranged between the second dichroic mirror 7b and the second reflection mirror 8b in the optical path of the blue illumination light LB. The second relay lens 9b is arranged between the second reflection mirror 8b and the third reflection mirror 8c in the optical path of the blue illumination light LB.

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

For example, a transmissive liquid crystal panel is used in the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B. Further, polarizing plates (not shown) are arranged on the incident side and the emitted side of the liquid crystal panel, respectively, so that only linearly polarized light in a specific direction can pass through.

A field lens 10R, a field lens 10G, and a field lens 10B are arranged on the incident side of the light modulation device 4R, the light modulation device 4G, and the light modulation device 4B, respectively. The field lens 10R, the field lens 10G, and the field lens 10B are the main rays of the red illumination light LR, the green illumination light LG, and the blue illumination light LB incident on the respective optical modulator 4R, optical modulator 4G, and optical modulator 4B. To parallelize.

The synthetic optical system 5 corresponds to the red illumination light LR, the green illumination light LG, and the blue illumination light LB by injecting the image light emitted from the optical modulator 4R, the optical modulator 4G, and the optical modulator 4B. The image light is synthesized, and the combined image light is emitted toward the projection optical device 6. For the composite optical system 5, for example, a cross dichroic prism is used.

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

Subsequently, the configuration of the light source device 2 will be described.
FIG. 2 is a diagram showing a schematic configuration of the light source device 2.
As shown in FIG. 2, the light source device 2 includes a first light source 21, a second light source 22, a polarization separation / synthesizing unit 23, and a uniform illumination optical system 24.

The first light source 21 includes a first light source unit 30 and a first pickup optical system 31. The first light source unit 30 is composed of an LED element or a laser element. The first light source unit 30 of the present embodiment includes at least one LED element or laser element, and emits blue light (first light) B. The blue light B is blue light having a first wavelength band, for example, a blue wavelength region of 400 nm to 480 nm, and a main wavelength of, for example, 450 nm.

The first pickup optical system 31 is composed of lenses 31a and 31b, and picks up the blue light B emitted from the first light source unit 30 and parallelizes it. Based on such a configuration, the first light source 21 emits blue illumination light LB toward the polarization separation / synthesis unit 23.

The second light source 22 includes an excitation light source 34, a wavelength conversion unit 35, and a second pickup optical system 36. In the light source device 2 of the present embodiment, the outputs of the first light source 21 and the second light source 22 can be controlled independently.

The wavelength conversion unit 35 converts the excitation light E in the excitation wavelength band, which contains at least a phosphor, into fluorescence Y in a third wavelength band different from the second wavelength band, which is the excitation wavelength. In the wavelength conversion unit 35, the excitation light E is incident from the first surface 35a facing the excitation light source 34, and the fluorescence Y is emitted from the second surface 35b facing away from the first surface 35a.

The wavelength conversion unit 35 includes a ceramic phosphor (polycrystalline phosphor) that converts the excitation light E into fluorescence Y. The wavelength band of fluorescence Y is, for example, a yellow wavelength range of 490 to 750 nm. That is, the fluorescence Y is a yellow fluorescence containing a red light component and a green light component.

The wavelength conversion unit 35 may include a single crystal phosphor instead of the polycrystalline phosphor. Alternatively, the wavelength conversion unit 35 may be made of fluorescent glass. Alternatively, the wavelength conversion unit 35 may be made of a material in which a large number of phosphor particles are dispersed in a binder made of glass or resin. The wavelength conversion unit 35 made of such a material converts the excitation light E into fluorescence Y.

Specifically, the material of the wavelength conversion unit 35 includes, for example, an yttrium aluminum garnet (YAG) -based phosphor. YAG containing cerium as an activator (Ce): Taking Ce example, as the material of the wavelength converter _35, mixed raw material powder containing _{Y 2 O 3, Al 2 O} 3, constituent elements of CeO _3, etc. Y—Al—O amorphous particles obtained by a wet method such as a co-precipitation method or a sol-gel method, and a gas phase method such as a spray drying method, a flame thermal decomposition method, or a thermal plasma method. YAG particles and the like can be used.

The excitation light source 34 has an LED element that emits excitation light E. The excitation light E is blue light having a second wavelength band, and is, for example, a blue wavelength region of 400 nm to 480 nm. In the present embodiment, the main wavelength of the excitation light E is, for example, 440 nm, which is shorter than the main wavelength of the blue light B. According to this configuration, the luminous efficiency of the fluorescence Y in the wavelength conversion unit 35 can be improved by using the excitation light E having the main wavelength on the short wavelength side having higher luminous efficiency.

In the second light source 22 of the present embodiment, the wavelength conversion unit 35 is laminated on the excitation light source 34. As a result, the excitation light E emitted from the excitation light source 34 can be efficiently incident on the wavelength conversion unit 35 to efficiently generate the fluorescence Y.

The polarization separation / synthesis unit 23 includes a dichroic mirror (light separation mirror) 50 having polarization separation characteristics for blue light B emitted from the first light source 21, a retardation plate 51, and a reflection unit 52.

The dichroic mirror 50 of the present embodiment transmits a part of the blue light B and reflects the rest of the part of the blue light B to make the blue light B an auxiliary excitation light (second light) B2 and a blue light. (Third light) Separated from B3. The dichroic mirror 50 transmits fluorescence Y regardless of the polarization direction.

FIG. 3 is a diagram showing the transmission characteristics of the dichroic mirror 50 of the present embodiment. The horizontal axis of FIG. 3 indicates the wavelength of light incident on the dichroic mirror 50. In FIG. 3, the transmission characteristic for P-polarized light is shown by a broken line, and the transmission characteristic for S-polarized light is shown by a solid line. In FIG. 3, each wavelength band of blue light B and fluorescence Y is shown.

As shown in FIG. 3, the dichroic mirror 50 of the present embodiment has a P-polarized light component in a wavelength band longer than the wavelength λ1 and an S-polarized light component in a wavelength band longer than the wavelength λ2 in the blue light B. It has the property of transmitting. Further, the dichroic mirror 50 of the present embodiment has a property of reflecting the P-polarized light component in the wavelength band shorter than the wavelength λ1 and the S-polarized light component in the wavelength band shorter than the wavelength λ2 in the blue light B. The long-short relationship between the wavelength λ1 and the wavelength λ2 and the main wavelength λB of the blue light B is not particularly limited, but may be appropriately adjusted in consideration of the light amount balance between the blue light B and the excitation light E. For example, either the wavelength λ1 or the wavelength λ2 may be longer than the main wavelength (peak wavelength) λB of the blue light B. Depending on the light amount balance between the blue light B and the excitation light E, both the wavelength λ1 and the wavelength λ2 may be longer than the main wavelength (peak wavelength) λB of the blue light B, and the wavelength λ1 and the wavelength λ2 may be longer. Both may be shorter than the main wavelength (peak wavelength) λB of the blue light B.

The dichroic mirror 50 of the present embodiment constitutes the blue light B3 by transmitting light containing a large amount of components on the long wavelength side among the components contained in the blue light B, and is short of the components contained in the blue light B. The auxiliary excitation light B2 is formed by reflecting light containing a large amount of wavelength-side components.

The auxiliary excitation light B2 separated from the blue light B by the dichroic mirror 50 is incident on the second pickup optical system 36. The second pickup optical system 36 is composed of lenses 36a and 36b, and causes the auxiliary excitation light B2 to be incident on the second surface 35b of the wavelength conversion unit 35 in a condensed state. The auxiliary excitation light B2 is light in the blue wavelength region, like the excitation light E emitted from the excitation light source 34. Therefore, the auxiliary excitation light B2 acts as excitation light in the wavelength conversion unit 35. That is, the second light source 22 generates fluorescence Y by wavelength-converting the excitation light E and the auxiliary excitation light B2 from the excitation light source 34.

The fluorescence Y emitted from the wavelength conversion unit 35 is incident on the second pickup optical system 36. The second pickup optical system 36 collects and parallelizes the fluorescence Y emitted from the wavelength conversion unit 35. Based on such a configuration, the second light source 22 emits fluorescence Y toward the polarization separation / synthesis unit 23.

On the other hand, the blue light B3 separated from the blue light B by the dichroic mirror 50 is incident on the retardation plate 51. The retardation plate 51 is composed of a quarter wave plate. The P-polarized light component contained in the blue light B3 is polarized 90 degrees by the retardation plate 51, converted into, for example, clockwise circularly polarized blue light B3c1, and then incident on the reflecting portion 52.

The reflecting unit 52 is composed of, for example, a plane mirror. That is, the reflecting unit 52 reflects the optical path of the blue light B3c1 so as to fold back in the opposite direction.

Hereinafter, the blue light B3c1 reflected by the reflecting unit 52 will be referred to as blue light B3c2. For example, the clockwise circularly polarized blue light B3c1 is reflected by the reflecting unit 52 as the counterclockwise circularly polarized blue light B3c2. The blue light B3c2 is incident on the retardation plate 51 again.

The counterclockwise circularly polarized blue light B3c2 is converted into S-polarized blue light B4 by the retardation plate 51. The S-polarized blue light B4 is incident on the dichroic mirror 50. The dichroic mirror 50 transmits the fluorescence Y emitted from the second light source 22 and reflects the blue light B4, so that the fluorescence Y and the blue light B4 are emitted in the same direction. The polarization separation / synthesizing unit 23 of the present embodiment generates a white illumination light WL by synthesizing the fluorescence Y and the blue light B4.

In the light source device 2 of the present embodiment, the blue light B3 passes through the dichroic mirror 50 and the retardation plate 51, enters the reflection unit 52, is reflected by the reflection unit 52, and passes through the retardation plate 51 again. It is converted to S-polarized blue light B4. The S-polarized blue light B4 is reflected by the dichroic mirror 50, and the fluorescence Y transmitted through the dichroic mirror 50 is combined with the blue light B4 reflected by the dichroic mirror 50.

Here, as a comparative example, consider a case where the blue light B emitted from the first light source 21 and the fluorescence Y generated by the second light source 22 are combined to generate white illumination light. In this case, when comparing the outputs of the blue light B and the fluorescence Y required to set the white balance in the illumination light to a predetermined value, the output of the fluorescence Y is insufficient as compared with the output of the blue light B. That is, when synthesizing the illumination light having a predetermined white balance, the output of the blue light B becomes a surplus with respect to the output of the fluorescence Y.

On the other hand, in the light source device 2 of the present embodiment, the auxiliary excitation light B2 separated from the blue light B emitted from the first light source 21 can be used for exciting the fluorescence Y in the wavelength conversion unit 35. That is, in the light source device 2 of the present embodiment, the surplus output of the blue light B is used to excite the fluorescence Y in the wavelength conversion unit 35.

The illumination light WL synthesized by the polarization separation / synthesis unit 23 is incident on the illumination uniform optical system 24. The illumination uniform optical system 24 includes an integrator optical system 41, a polarization conversion element 42, and a superimposing lens 43.

The integrator optical system 41 is composed of, for example, a lens array 41a and a lens array 41b. Each of the lens arrays 41a and 41b includes a plurality of small lenses arranged in an array.

The illumination light WL transmitted through the integrator optical system 41 is incident on the polarization conversion element 42. The polarization conversion element 42 converts the polarization direction of the light emitted from the integrator optical system 41. Specifically, the polarization conversion element 42 is divided by the lens array 41a, and each partial luminous flux emitted from the lens array 41b is converted into linearly polarized light. The polarization conversion element 42 has a polarization separation layer and a polarization separation layer that transmit one of the polarization components contained in the illumination light WL as it is and reflect the other linear polarization component in a direction perpendicular to the optical axis. It has a reflective layer that reflects the other linearly polarized light component reflected by the light axis in a direction parallel to the optical axis, and a retardation plate that converts the other linearly polarized light component reflected by the reflective layer into one linearly polarized light component. ing.

The illumination light WL transmitted through the polarization conversion element 42 is incident on the superimposing lens 43. The superimposing lens 43 cooperates with the integrator optical system 41 to make the illuminance distribution by the illumination light WL in the illuminated region uniform. In this way, the light source device 2 of the present embodiment emits the illumination light WL.

According to the light source device 2 of the present embodiment, the following effects are obtained.
The light source device 2 of the present embodiment includes a first light source 21 that emits blue light B, an excitation light source 34 that emits excitation light E, and a second light source 22 having a wavelength conversion unit 35 that generates fluorescence Y. A polarization separation / synthesis unit 23 in which blue light B emitted from the first light source 21 and fluorescence Y emitted from the second light source 22 are incident is provided, and the polarization separation / synthesis unit 23 emits light from the first light source 21. The resulting blue light B is separated into auxiliary excitation light B2 and blue light B3, the auxiliary excitation light B2 is incident on the wavelength conversion unit 35 of the second light source 22, and the second light source 22 is excited by the excitation light source 34. The wavelength conversion unit 35 converts the light E and the auxiliary excitation light B2 into wavelengths to generate the fluorescence Y, and the polarization separation / synthesis unit 23 combines the fluorescence Y and the blue light B4 to generate the illumination light WL.

According to the light source device 2 of the present embodiment, the surplus output of the blue light B can be used for exciting the fluorescence Y in the wavelength conversion unit 35. As a result, it is possible to generate high-luminance fluorescence Y as compared with the case where the wavelength conversion unit 35 is excited only by the excitation light source 34 to generate fluorescence Y. Therefore, by synthesizing the high-luminance fluorescence Y and the blue light B4, a bright illumination light WL having a desired white balance can be generated.
Further, according to the light source device 2 of the present embodiment, the white balance of the illumination light WL can be easily adjusted by independently controlling the outputs of the first light source 21 and the second light source 22.

In the light source device 2 of the present embodiment, the polarization separation / synthesis unit 23 includes a dichroic mirror 50 having polarization separation characteristics with respect to blue light B, a retardation plate 51, and a reflection unit 52, and the blue light B is a dichroic. The auxiliary excitation light B2 and the blue light B3 are separated by the mirror 50. Further, the auxiliary excitation light B2 is reflected by the dichroic mirror 50 toward the wavelength conversion unit 35 of the second light source 22, and the blue light B3 passes through the dichroic mirror 50 and the retardation plate 51 and is incident on the reflection unit 52. , The fluorescent Y reflected by the reflecting unit 52, passed through the retardation plate 51 again, reflected by the dichroic mirror 50, and transmitted through the dichroic mirror 50 is combined with the blue light B4 reflected by the dichroic mirror 50.
According to this configuration, it is possible to realize a configuration in which the blue light B is separated into the auxiliary excitation light B2 and the blue light B3 by the polarization separation / synthesis unit 23. Further, by transmitting the retardation plate 51 twice, it is possible to obtain the blue light B4 in which the polarization direction of the blue light B3 is rotated by 90 degrees. Thereby, the illumination light WL which combines the blue light B4 and the fluorescence Y can be generated.

In the light source device 2 of the present embodiment, the wavelength of the auxiliary excitation light B2 is shorter than the wavelength of the blue light B3.
According to this configuration, as the auxiliary excitation light B2, the light on the short wavelength side, which has higher luminous efficiency of fluorescence Y, can be separated from the blue light B. As a result, the luminous efficiency of the fluorescence Y of the wavelength conversion unit 35 by the auxiliary excitation light B2 can be improved.
Further, as the blue light B3, the light on the long wavelength side contained in the blue light B can be separated. Thereby, for example, it is possible to reduce the burden on the optical component made of an organic material such as the polarizing plate provided on the incident side and the ejection side of the liquid crystal panel and to extend the life.
Further, since the blue component contained in the illumination light WL is composed of the light on the long wavelength side, light having a wavelength close to the apex on the blue side of the color triangle of sRGB is generated as the blue illumination light LB separated from the illumination light WL. NS. Therefore, since the illumination light WL that covers the color gamut of sRGB is generated, it is possible to display with excellent color reproducibility by using the illumination light WL for the image display of the projector 1.

In the light source device 2 of the present embodiment, the first light source 21 includes an LED element, and the excitation light source 34 includes an LED element.
By configuring the first light source 21 and the excitation light source 34 with LED elements, the cost of the light source device 2 can be reduced.

In the light source device 2 of the present embodiment, the blue light B is blue light having a first wavelength band, the excitation light E is blue light having a second wavelength band, and the main wavelength of the excitation light E is blue light B. Shorter than the main wavelength of.
According to this configuration, since light having a main wavelength on the short wavelength side having higher luminous efficiency is used as the excitation light E, the luminous efficiency of the fluorescence Y in the wavelength conversion unit 35 can be improved.
Further, by selecting a light source having a longer main wavelength than the excitation light source 34 as the first light source unit 30 for emitting blue light B, while obtaining high output, for example, polarized light provided on the incident side and the emission side of the liquid crystal panel is provided. The life can be extended by reducing the burden on the optical component made of an organic material such as a plate.

In the light source device 2 of the present embodiment, in the second light source 22, the wavelength conversion unit 35 is laminated on the excitation light source 34.
According to this configuration, the excitation light E emitted from the excitation light source 34 can be efficiently incident on the wavelength conversion unit 35 to efficiently generate the fluorescence Y.

The projector 1 of the present embodiment includes a light source device 2, light modulation devices 4R, 4G, 4B that modulate the light from the light source device 2 according to image information, and light modulated by the light modulation devices 4R, 4G, 4B. The projection optical device 6 for projecting the light source is provided.

According to the projector 1 of the present embodiment, since the light source device 2 that generates a bright illumination light WL having a desired white balance is provided, a bright image having an excellent color balance can be displayed.

(Second Embodiment)
Subsequently, the light source device of the second embodiment will be described. The same reference numerals are given to the configurations common to those of the first embodiment, and the details thereof will be omitted.
FIG. 4 is a diagram showing a schematic configuration of the light source device 102 of the present embodiment.
As shown in FIG. 4, the light source device 102 of the present embodiment includes a first light source 21, a second light source 22, a polarization separation / synthesizing unit 123, and a uniform illumination optical system 24.

The polarization separation / synthesis unit 123 includes a dichroic mirror (light separation mirror) 150, a retardation plate 51, and a reflection unit 52.

The dichroic mirror 150 of the present embodiment separates the blue light B emitted from the first light source 21 into the auxiliary excitation light B2 and the blue light B3. The dichroic mirror 150 transmits the fluorescence Y regardless of the polarization direction.

The dichroic mirror 150 of the present embodiment is composed of an edge path filter that reflects light in the wavelength band between the long wavelength side of blue light B and fluorescence Y, transmits the short wavelength side of blue light B, and transmits fluorescence Y. Will be done.

FIG. 5 is a diagram showing the transmission characteristics of the dichroic mirror 150 of the present embodiment. The horizontal axis of FIG. 5 indicates the wavelength of light incident on the dichroic mirror 150. In FIG. 5, the transmission characteristic for P-polarized light is shown by a solid line, and the transmission characteristic for S-polarized light is shown by a broken line. In FIG. 5, each wavelength band of blue light B and fluorescence Y is shown.

Specifically, as shown in FIG. 5, the dichroic mirror 150 of the present embodiment has an S-polarized light component having a wavelength band shorter than the wavelength λ3 and a P-polarized light component having a wavelength band shorter than the wavelength λ4 of the blue light B. And have the property of transmitting. Further, the dichroic mirror 150 of the present embodiment has a characteristic of reflecting the S-polarized light component in the wavelength band longer than the wavelength λ3 and the P-polarized light component in the wavelength band longer than the wavelength λ4 in the blue light B. For example, the wavelength λ3 is shorter than the main wavelength λB of blue light B, and the wavelength λ4 is longer than the main wavelength λB of blue light B.

The dichroic mirror 150 of the present embodiment constitutes the auxiliary excitation light B2 by transmitting light containing a large amount of short wavelength side components among the components contained in the blue light B, and among the components contained in the blue light B. The blue light B3 is formed by reflecting light containing a large amount of components on the long wavelength side. Therefore, the wavelength of the blue light B3 is longer than the wavelength of the auxiliary excitation light B2.

The blue light B3 separated from the blue light B by the dichroic mirror 150 is emitted toward the uniform illumination optical system 24.

On the other hand, the auxiliary excitation light B2 separated from the blue light B by the dichroic mirror 150 is incident on the retardation plate 51. The retardation plate 51 is composed of a quarter wave plate. The P-polarized light component contained in the auxiliary excitation light B2 is converted into, for example, clockwise circularly polarized auxiliary excitation light B2c1 by the retardation plate 51, and then incident on the reflection unit 52. The reflecting unit 52 reflects the optical path of the auxiliary excitation light B2c1 so as to fold back in the opposite direction.

Hereinafter, the auxiliary excitation light B2c1 reflected by the reflecting unit 52 is referred to as an auxiliary excitation light B2c2. For example, the clockwise circularly polarized auxiliary excitation light B2c1 is reflected by the reflecting unit 52 as the counterclockwise circularly polarized auxiliary excitation light B2c2. The auxiliary excitation light B2c2 is incident on the retardation plate 51 again.

The counterclockwise circularly polarized auxiliary excitation light B2c2 is converted into S-polarized auxiliary excitation light B5 by the retardation plate 51. The S-polarized auxiliary excitation light B5 is incident on the dichroic mirror 150. The dichroic mirror 150 reflects a component of the auxiliary excitation light B5 on the shorter wavelength side than the wavelength λ3 toward the second light source 22.

The auxiliary excitation light B5 reflected by the dichroic mirror 150 is incident on the second pickup optical system 36. The second pickup optical system 36 causes the auxiliary excitation light B5 to be incident on the second surface 35b of the wavelength conversion unit 35 in a condensed state. The auxiliary excitation light B5 is light in the blue wavelength region, like the excitation light E emitted from the excitation light source 34. Therefore, the auxiliary excitation light B5 acts as excitation light in the wavelength conversion unit 35. That is, the second light source 22 generates fluorescence Y by wavelength-converting the excitation light E and the auxiliary excitation light B5 from the excitation light source 34. The fluorescence Y passes through the dichroic mirror 150 and is emitted toward the uniform illumination optical system 24.

As described above, in the polarization separation / synthesis unit 123 of the present embodiment, the P polarization component contained in the auxiliary excitation light B2 passes through the dichroic mirror 150 and the retardation plate 51 and is incident on the reflection unit 52, and is incident on the reflection unit 52 by the reflection unit 52. It is reflected and passes through the retardation plate 51 again to be converted into S-polarized auxiliary excitation light B5. The S-polarized auxiliary excitation light B5 is reflected by the dichroic mirror 150 toward the wavelength conversion unit 35 of the second light source 22.

The fluorescence Y transmitted through the dichroic mirror 150 is combined with the blue light B3 reflected by the dichroic mirror 150. The polarization separation / synthesizing unit 123 of the present embodiment generates a white illumination light WL by synthesizing the fluorescence Y and the blue light B3.

According to the light source device 102 of the present embodiment, the following effects are obtained.
In the light source device 102 of the present embodiment, the blue light B3 separated from the blue light B in the dichroic mirror 150 can be directly incident on the integrator optical system 41 of the illumination uniform optical system 24. Here, the blue light B emitted from the first light source unit 30 is substantially parallelized by the first pickup optical system 31, but also contains a divergent component in which the luminous flux is slightly expanded. That is, the blue light B3 separated from the blue light B also contains a divergent component as well.

According to the configuration of the present embodiment, the distance from the first light source unit 30 that emits the blue light B to the integrator optical system 41 is shorter than that of the configuration of the first embodiment. Therefore, the light loss can be reduced by incorporating the divergent component contained in the blue light B3 into the lens array 41a of the integrator optical system 41.

Further, also in the light source device 102 of the present embodiment, high-luminance fluorescence Y can be generated by using the surplus output of blue light B for excitation of fluorescence Y in the wavelength conversion unit 35. Therefore, by synthesizing the high-luminance fluorescence Y and the blue light B3, a bright illumination light WL having a desired white balance can be generated.

The polarization separation / synthesis unit 123 can generate the auxiliary excitation light B5 in which the polarization direction of the auxiliary excitation light B2 is rotated by 90 degrees by transmitting the retardation plate 51 twice. As a result, the auxiliary excitation light B2 can be incident on the wavelength conversion unit 35 of the second light source 22 as excitation light.

Among the components contained in the blue light B, the light on the short wavelength side having high luminous efficiency of fluorescence Y can be used as the auxiliary excitation light B5. As a result, the luminous efficiency of the fluorescence Y of the wavelength conversion unit 35 can be improved. Further, as the blue light B3, the light on the long wavelength side contained in the blue light B can be separated, so that the burden on the optical component made of an organic material can be reduced and the life can be extended as in the first embodiment. can.

(Third Embodiment)
Subsequently, the light source device of the third embodiment will be described. The same reference numerals are given to the configurations common to those of the first embodiment, and the details thereof will be omitted.
FIG. 6 is a diagram showing a schematic configuration of the light source device 202 of the present embodiment.
As shown in FIG. 6, the light source device 202 of the present embodiment includes a first light source 21, a second light source 22, a polarization separation / synthesizing unit 223, and a uniform illumination optical system 24.

The polarization separation / synthesis unit 223 includes a dichroic mirror (light separation mirror) 250, a retardation plate 51, and a reflection unit 52.

The dichroic mirror 250 of the present embodiment separates the blue light B emitted from the first light source 21 into the auxiliary excitation light B2 and the blue light B3. The dichroic mirror 250 reflects the fluorescence Y regardless of the polarization direction.

FIG. 7 is a diagram showing the transmission characteristics of the dichroic mirror 250 of the present embodiment. The horizontal axis of FIG. 7 indicates the wavelength of light incident on the dichroic mirror 250. In FIG. 7, the transmission characteristic for P-polarized light is shown by a solid line, and the transmission characteristic for S-polarized light is shown by a broken line. In FIG. 7, each wavelength band of blue light B and fluorescence Y is shown.

Specifically, as shown in FIG. 7, the dichroic mirror 250 of the present embodiment has a property of transmitting a P-polarized light component of blue light B and an S-polarized light component in a wavelength band shorter than the wavelength λ5. Further, the dichroic mirror 250 of the present embodiment has a characteristic of reflecting the S polarization component of the blue light B having a wavelength band longer than the wavelength λ5. The wavelength λ5 is not particularly limited to the main wavelength λB of the blue light B, but may be appropriately adjusted in consideration of the light amount balance between the blue light B and the excitation light E. For example, the wavelength λ5 may be longer than the main wavelength λB of blue light B. Alternatively, λ5 may be shorter than λB depending on the light amount balance between the blue light B and the excitation light E.

The dichroic mirror 250 of the present embodiment constitutes the auxiliary excitation light B2 by transmitting light containing a large amount of short wavelength side components among the components contained in the blue light B, and among the components contained in the blue light B. The blue light B3 is formed by reflecting light containing a large amount of components on the long wavelength side.

The blue light B3 reflected by the dichroic mirror 250 and separated from the blue light B is incident on the retardation plate 51. The blue light B3 composed of the S-polarized light component is converted into, for example, counterclockwise circularly polarized blue light B3c3 by the retardation plate 51, and then incident on the reflecting unit 52 and reflected. The counterclockwise circularly polarized blue light B3c3 is reflected by the reflecting unit 52 as clockwise circularly polarized blue light B3c4. The blue light B3c4 is incident on the retardation plate 51 again. The clockwise circularly polarized blue light B3c4 is converted into P-polarized blue light B6 by the retardation plate 51. The P-polarized blue light B6 passes through the dichroic mirror 250.

On the other hand, the auxiliary excitation light B2 separated from the blue light B by passing through the dichroic mirror 250 is incident on the second pickup optical system 36, and is incident on the second surface 35b of the wavelength conversion unit 35 in a condensed state. The second light source 22 generates fluorescence Y by wavelength-converting the excitation light E and the auxiliary excitation light B2 from the excitation light source 34. The fluorescence Y is reflected by the dichroic mirror 250 toward the uniform illumination optical system 24.

As described above, in the polarization separation / synthesis unit 223 of the present embodiment, the auxiliary excitation light B2 passes through the dichroic mirror 250 and is incident on the wavelength conversion unit 35 of the second light source 22, and the blue light B3 is transmitted by the dichroic mirror 250. It is reflected, passes through the retardation plate 51, enters the reflection unit 52, is reflected by the reflection unit 52, passes through the retardation plate 51 again, and passes through the dichroic mirror 250 as blue light B6. The fluorescence Y emitted from the second light source 22 is reflected by the dichroic mirror 250, and the fluorescence Y reflected by the dichroic mirror 250 is combined with the blue light B6 transmitted through the dichroic mirror 250. The polarization separation synthesis unit 223 of the present embodiment generates a white illumination light WL by synthesizing the fluorescence Y and the blue light B6.

Also in the light source device 202 of the present embodiment, high-luminance fluorescence Y can be generated by using the surplus output of blue light B for excitation of fluorescence Y in the wavelength conversion unit 35. Therefore, by synthesizing the high-luminance fluorescence Y and the blue light B3, a bright illumination light WL having a desired white balance can be generated.

Further, according to the light source device 202 of the present embodiment, since the first light source 21 and the second light source 22 are arranged so as to sandwich the illumination light axis AX of the light source device 202, the dimensions in the direction along the illumination light axis AX are determined. Can be made smaller. Therefore, the light source device 202 whose dimensions in the direction along the illumination optical axis AX are miniaturized is provided. By using the miniaturized light source device 202, the degree of freedom in layout when incorporating the light source device 202 into the projector 1 is increased.

(Fourth Embodiment)
Subsequently, the projector of the fourth embodiment will be described.
FIG. 8 is a diagram showing a schematic configuration of the projector 101 of the present embodiment.
As shown in FIG. 8, the projector 101 of the present embodiment includes the light source device 2 of the first embodiment, a condenser lens 70, a color wheel 71, a rod lens 72, a relay optical system 73, and a micromirror type. It includes an optical modulator 74, a total reflection prism 75, and a projection optical device 76.

The light source device 2 emits white illumination light WL toward the condenser lens 70. The condenser lens 70 causes the illumination light WL to enter the color wheel 71. The color wheel 71 includes a color filter corresponding to red light, green light, and blue light, and generates and emits red illumination light LR, green illumination light LG, and blue illumination light LB from the white illumination light WL in chronological order. The red illumination light LR, the green illumination light LG, and the blue illumination light LB emitted from the color wheel 71 in chronological order are incident on the rod lens 72.

The rod lens 72 includes a light incident surface 72a and a light emitting surface 72b. The rod lens 72 totally reflects the light incident on the inside from the light incident surface 72a on the inner surface, and then emits the light from the light emitting surface 72b to make the light intensity distribution uniform.

The relay optical system 73 cooperates with the rod lens 72 to emit red illumination light LR, green illumination light LG, and blue illumination light LB having a uniform intensity distribution toward the total reflection prism 75. The total reflection prism 75 is composed of a translucent member and includes a reflection surface 75a. The angle of the reflecting surface 75a is set so as to totally reflect the red illumination light LR, the green illumination light LG, and the blue illumination light LB that are incident in time sequence toward the micromirror type optical modulator 74.

The micromirror type optical modulator 74 is composed of, for example, a DMD (Digital Micromirror Device). A DMD is a matrix in which a plurality of micromirrors are arranged. The DMD switches the reflection direction of the incident light between the direction transmitted through the reflecting surface 75a and the direction reflected by the reflecting surface 75a by switching the tilting direction of the plurality of micromirrors.

In this way, the micromirror type optical modulator 74 composed of the DMD sequentially modulates the red illumination light LR, the green illumination light LG, and the blue illumination light LB generated in time by the color wheel 71, and sequentially modulates the green image light and the red illumination. Generates image light and blue image light. The projection optical device 76 projects green image light, red image light, and blue image light onto a screen (not shown).

As described above, according to the projector 101 of the present embodiment, when the micromirror type optical modulation device 74 is used, a bright image having a desired white balance can be displayed.

As the light source device of the projector 101 of the present embodiment, the light source device 102 of the second embodiment or the light source device 202 of the third embodiment may be used.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the case where the first light source unit 30 of the first light source 21 includes an LED element has been described as an example, but the first light source unit 30 may be composed of a laser element. When a laser element is used as the first light source unit 30, it is desirable to provide a diffusing member for diffusing blue light composed of laser light between the dichroic mirror and the reflecting unit.

Further, in the second light source 22, the case where the excitation light source 34 and the wavelength conversion unit 35 are laminated is given as an example, but the wavelength conversion unit is composed of a rod-shaped phosphor and is excited from the side surface of the rod-shaped phosphor. A structure in which the excitation light of the light source is incident may be adopted.

Further, in the above embodiment, an example in which the light source device of the present invention is mounted on a projector is shown, but the present invention is not limited to this. The light source device of the present invention can also be applied to lighting equipment, automobile headlights, and the like.

1,101 ... Projector, 2,102,202 ... Light source device, 4B, 4G, 4R ... Light modulator, 6,76 ... Projection optical device, 21 ... First light source, 22 ... Second light source, 23,123,223 ... Polarization separation / synthesis unit, 34 ... Excitation light source, 35 ... Wavelength converter, 50, 150, 250 ... Dycroic mirror (light separation mirror), 51 ... Phase difference plate, 52 ... Reflection unit, B, B3, B4, B6 B3c1, B3c2, B3c3, B3c4 ... blue light, B ... blue light (first light), B2 ... auxiliary excitation light (second light), B3 ... blue light (third light), E ... excitation light, WL ... illumination Light, Y ... fluorescence, λ1, λ2, λ3, λ4, λ5 ... wavelength, λB ... main wavelength.

Claims (10)

The first light source that emits the first light and
A second light source having an excitation light source that emits excitation light and a wavelength conversion unit that generates fluorescence.
A polarization separation / synthesizing unit in which the first light emitted from the first light source and the fluorescence emitted from the second light source are incident is provided.
The polarization separation / synthesizing unit separates the first light emitted from the first light source into a second light and a third light.
The second light is incident on the wavelength conversion unit of the second light source, and the second light is incident on the wavelength conversion unit.
The second light source generates the fluorescence by wavelength-converting the excitation light from the excitation light source and the second light in the wavelength conversion unit.
The polarization separation / synthesizing unit is a light source device characterized in that the fluorescence and the third light are combined to generate illumination light. The polarization separation / synthesis unit includes a light separation mirror having polarization separation characteristics with respect to the first light, a retardation plate, and a reflection unit.
The light source device according to claim 1, wherein the first light is separated into the second light and the third light by the light separation mirror. The second light is reflected by the light separation mirror toward the wavelength conversion unit of the second light source.
The third light passes through the light separation mirror and the retardation plate, enters the reflection portion, is reflected by the reflection portion, passes through the retardation plate again, and is reflected by the light separation mirror.
The light source device according to claim 2, wherein the fluorescence transmitted through the light separation mirror is combined with the third light reflected by the light separation mirror. The second light passes through the light separation mirror and the retardation plate, enters the reflection portion, is reflected by the reflection portion, passes through the retardation plate again, and is passed through the retardation plate again by the light separation mirror. It is reflected toward the wavelength conversion part of the light source and
The light source device according to claim 2, wherein the fluorescence transmitted through the light separation mirror is reflected by the light separation mirror and combined with the third light separated from the first light. The second light passes through the light separation mirror and is incident on the wavelength conversion unit of the second light source.
The third light is reflected by the light separation mirror, passes through the retardation plate, enters the reflection portion, is reflected by the reflection portion, passes through the retardation plate again, and passes through the retardation plate to pass through the light separation mirror. Transparent,
The fluorescence emitted from the second light source is reflected by the light separation mirror and is reflected by the light separation mirror.
The light source device according to claim 2, wherein the fluorescence reflected by the light separation mirror is combined with the third light transmitted through the light separation mirror. The light source device according to any one of claims 1 to 3, wherein the wavelength of the second light is shorter than the wavelength of the third light. The first light source includes an LED element or a laser element, and includes an LED element or a laser element.
The light source device according to any one of claims 1 to 4, wherein the excitation light source includes an LED element. The first light is blue light having a first wavelength band.
The excitation light is blue light having a second wavelength band, and is
The light source device according to any one of claims 1 to 5, wherein the main wavelength of the excitation light is shorter than the main wavelength of the first light. The light source device according to any one of claims 1 to 6, wherein in the second light source, the wavelength conversion unit is laminated on the excitation light source. The light source device according to any one of claims 1 to 7.
An optical modulation device that modulates the light from the light source device according to image information,
A projector including a projection optical device that projects light modulated by the light modulation device.

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