JP2021096398A - Light source device and image projection device including the same - Google Patents

Abstract

To provide a light source device that can adjust the color balance of a projected image while maintaining the brightness of the image, and an image projection device including the same.SOLUTION: A light source device has: a first light source that emits first color light; a wavelength conversion unit that converts at least partial light of the first color light into fluorescent light including the wavelengths of second color light different in wavelength from the first color light and third color light different in wavelength from the first color light and the second color light; and a second light source that emits auxiliary color light including a wavelength different from the wavelength of the first color light, and the light source device sequentially emits the first color light and the fluorescent light. The first color light and the second color light separated from fluorescent light are incident on a first image display element. The third color light separated from the fluorescent light is incident on the second image display element. The auxiliary color light is incident on a second image display element in at least partial time of the time during which the first color light is emitted.SELECTED DRAWING: Figure 1

Description

The present invention relates to a light source device and an image projection device including the light source device.

Conventionally, a two-plate image projection device is known in which two image display elements are irradiated with a light flux generated from a light source, and each image display element projects a light flux modulated according to an image signal. A two-plate image projection device is known in which a luminous flux from a blue laser diode is used as excitation light to irradiate a phosphor, and wavelength-converted fluorescent light and blue light from a blue laser diode are used as light sources. However, while the blue light is emitted from the light source device, one of the two image display elements to which the blue light is incident is used for image output, but the other image to which the blue light is not incident is used. The display element is not used effectively.

Patent Document 1 discloses an image projection device that sequentially excites a yellow phosphor and a cyan phosphor and incidents the generated yellow light and cyan light on an image display element. In the image projection device of Patent Document 1, since blue light and green light are formed from cyan light by a color separating element, green light is incident on the other image display element at the timing when the blue light is incident on one image display element. However, it is possible to eliminate the unused time of the image display element.

Special Table 2015-533225

However, in the image projection apparatus of Patent Document 1, the power of blue light contained in the fluorescent light emitted from the cyan phosphor is significantly smaller than the power of blue light of the blue laser diode. Therefore, the power of the blue light component is insufficient as compared with the yellow light component, and the white balance of the projected image may be lost. In order to avoid this, it is sufficient to lengthen the time for incident the excitation light on the cyan phosphor to increase the blue light component, but the time for incident the excitation light on the yellow phosphor is shortened. In this case, the yellow phosphor generally contains a large amount of wavelength components having a higher luminous efficiency than the cyan phosphor and also has a high quantum efficiency, so that there is a problem that the brightness of the projected image becomes dark. is there.

An object of the present invention is to provide a light source device capable of adjusting a color balance while maintaining the brightness of a projected image, and an image projection device including the same.

The light source device as one aspect of the present invention includes a first light source that emits first color light, and a second color light and first and second color light that emit at least a part of the first color light with a wavelength different from that of the first color light. It has a wavelength converter that converts light into fluorescent light that includes a wavelength of third color light that is different from the wavelength, and a second light source that emits auxiliary color light that contains a wavelength that is different from the wavelength of the first color light. The light source device that sequentially emits light and the second color light separated from the first color light and the fluorescent light enter the first image display element, and the third color light separated from the fluorescent light enters the second image display element. The incident and auxiliary color light are characterized in that they are incident on the second image display element at least a part of the time during which the first color light is emitted.

Further, the image projection device as another aspect of the present invention includes a first light source that emits first color light, a second color light that emits at least a part of the first color light, and a second color light that differs from the wavelength of the first color light. It is provided with a wavelength conversion unit that converts to fluorescent light containing a wavelength of third color light different from the wavelength of second color light, and a second light source that emits auxiliary color light containing a wavelength different from the wavelength of first color light. A light source device that sequentially emits fluorescent light, a first image display element in which a first color light and a second color light separated from the fluorescent light are incident, and a second image in which a third color light separated from the fluorescent light is incident. It has a display element, and the auxiliary color light is incident on the second image display element at least a part of the time during which the first color light is emitted.

According to the present invention, it is possible to provide a light source device capable of adjusting a color balance while maintaining the brightness of a projected image, and an image projection device including the light source device.

It is a block diagram of the image projection apparatus equipped with the light source apparatus of Example 1. FIG. It is a block diagram of the phosphor wheel of Example 1. FIG. It is explanatory drawing of the subject of this invention. It is explanatory drawing of the effect of Example 1. FIG. It is explanatory drawing of an example of the color balance correction method of Example 1. FIG. It is explanatory drawing of another example of the color balance correction method of Example 1. FIG. It is explanatory drawing of the effect of Example 2. It is a figure which shows an example of the color balance correction method of Example 2. It is a block diagram of the image projection apparatus equipped with the light source apparatus of Example 3. FIG. It is a front view of a partial dichroic mirror. It is a spectroscopic characteristic diagram of a partial dichroic mirror. It is a block diagram of the phosphor wheel of Example 3. FIG.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In each figure, the same member is given the same reference number, and duplicate description is omitted.

FIG. 1 is a configuration diagram of an image projection device 100 equipped with the light source device 50 of this embodiment. In FIGS. 1A and 1B, the rotational positions of the phosphor wheel (wavelength conversion unit) 6 are different, and light of different colors is emitted from the light source device 50.

The image projection device 100 includes a light source device 50 and an illumination optical system. The light source device 50 includes a blue laser light source 1, a positive lens 2, 12, a negative lens 3, 13, a dichroic mirror 4, 8, a condenser lens 5, a phosphor wheel 6, a collimating lens 7, a relay lens system 9, and an optical path bending mirror. It has 10, 14 and an auxiliary light source 11. The illumination optical system includes an illumination lens 15, an optical path bending mirror 16, a total reflection prism 17, a color separation prism 18, a first image display element 19, and a second image display element 20.

The blue laser light source 1 is composed of a plurality of light sources, and each light source emits blue light having a main wavelength of 450 nm. The luminous flux emitted from each light source travels toward the positive lens 2 as a parallel luminous flux. The first color light (blue light) L1 is focused by the positive lens 12 and parallelized by the negative lens 3. As a result, the width of the luminous flux is set to an appropriate size.

The first color light L1 emitted from the negative lens 3 is incident on the dichroic mirror 4. The dichroic mirror 4 has a spectral characteristic that reflects light in a wavelength band of 470 nm or less and transmits light in a wavelength band of 470 nm or more. Therefore, the first color light L1 is reflected by the dichroic mirror 4 and is incident on the condenser lens 5. The first color light L1 incident on the condenser lens 5 is focused on the phosphor wheel 6.

FIG. 2 is a block diagram of the phosphor wheel 6 of the first embodiment. The phosphor wheel 6 sets at least a part of the light of the first color light L1 to a wavelength of the second color light L2 different from the wavelength of the first color light L1 and a wavelength of the third color light L3 different from the wavelengths of the first color light L1 and the second color light L2. Convert to include fluorescent light _Lphos. In the phosphor wheel 6, a phosphor layer 6b in which a phosphor is fixed by a silicon-based binder is formed on the circumference of a metal wheel 6a having excellent thermal conductivity such as highly reflective aluminum. A part of the region of the phosphor layer 6b is notched together with the metal wheel 6a, and a translucent diffusing layer (diffusing element) 6c is formed instead. The diffusion layer 6c may be frosted glass or a microlens array. Reference numeral 6d is a focusing spot of the first color light L1 focused on the phosphor wheel 6.

The first color light L1 is focused on the phosphor layer 6b at a certain time as shown in FIG. 2 (a). When the first color light L1 is focused on the phosphor layer 6b at the time corresponding to FIG. 2A, the phosphor absorbs the first color light L1 and is excited. The first color light L1 is converted into _{fluorescent light L phos} containing a wavelength component of 480 nm to 700 nm. Fluorescent light _Lphos is generated in all directions, but most of the components are reflected by the metal wheel 6a and travel toward the condenser lens 5.

_{In FIG. 1A, the fluorescent light Lphos} incident on the condenser lens 5 is incident on the dichroic mirror 4. As described above, since the dichroic mirror 4 has a spectral characteristic of transmitting light in a wavelength band of 470 nm or more, the fluorescent light _Lphos passes through the dichroic mirror 4 and is emitted from the light source device 50 toward the illumination lens 15. The fluorescent light _Lphos is molded into an appropriate shape by the illumination lens 15 and guided to the total reflection prism 17 via the folding mirror 16. The total reflection prism 17 is an element in which two prisms are joined via an air gap layer of about 10 μm. _{The fluorescent light Lphos} incident on the air gap layer causes total internal reflection and the optical path is bent. The bent fluorescent light L _phos is incident on the color separation prism 18.

In the color separation prism 18, a dielectric multilayer film is formed on the joint surface of the two right-angle prisms. The color separation prism 18 has a spectral characteristic of transmitting blue light in the wavelength band of 430 nm to 480 nm and red light in the wavelength band of 600 to 700 nm and reflecting green light in the wavelength band of 490 nm to 590 nm. Fluorescent light _{L phos} including a wavelength component of 480nm~700nm is by the color separation prism 18 is separated into a second color light (red light) L2 and the third color light (green light) L3. The second color light L2 and the third color light L3 are incident on the first image display element 19 and the second image display element 20, respectively.

In the first and second image display elements 19 and 20, a large number of micromirrors corresponding to pixels are arranged, and by switching the angle of each micromirror to control the ON / OFF state, the incident light is modulated and an image is displayed. It is a so-called digital micromirror device. The light reflected on each image display element is recombined by the color separation prism 18 and then re-entered into the air gap layer of the total reflection prism 17, but when the angle of the minute mirror is switched to the ON state, It is set to transmit beyond the critical angle. The light transmitted through the total reflection prism 17 is guided to a projection optical system (not shown) arranged on the transmission optical path side of the total reflection prism 17. An image based on the light guided by the projection optical system is projected onto the projected surface by the projection optical system.

As the first and second image display elements 19 and 20, reflective or transmissive liquid crystal panels may be used. In the former case, a polarizing beam splitter or the like can be used as an element for switching the optical path, and in the latter case, color separation may be performed by a dichroic mirror or the like, and color synthesis may be performed by a dichroic prism or the like of another member.

When the phosphor wheel 6 rotates from the time corresponding to FIG. 2A, the first color light L1 is focused on the diffusion layer 6c at a certain time as shown in FIG. 2B. When the first color light L1 is focused on the diffusion layer 6c at the time corresponding to FIG. 2B, the region corresponding to the diffusion layer 6c of the metal wheel 6a is cut out, so that the first color light L1 Passes through the diffusion layer 6c and is incident on the collimating lens 7.

In FIG. 1B, the first color light L1 incident on the collimating lens 7 is incident on the dichroic mirror 8. The dichroic mirror 8 has the same spectral characteristics as the dichroic mirror 4, and the first color light L1 is reflected. After that, the first color light L1 enters the dichroic mirror 4 via the relay lens system 9 and the optical path bending mirror 10. The first color light L1 is reflected by the dichroic mirror 4 and emitted from the light source device 50 toward the illumination lens 15. The first color light L1 is incident on the color separation prism 18 via the illumination lens 15, the bending mirror 16, and the total reflection prism 17. Since the color separation prism 18 has a spectral characteristic of transmitting blue light in a wavelength band of 430 nm to 480 nm, the first color light L1 is incident on the first image display element 19. Since the optical path after that is the same as that of the fluorescent light Lphos, detailed description thereof will be omitted.

FIG. 3 is an explanatory diagram of the subject of the present invention. FIG. 3A shows the light emitted from the light source device 50 over time. As described above, the light source device 50 _{sequentially emits the fluorescent light L phos} and the first color light L1 according to the rotation of the phosphor wheel 6. 3 (b) and 3 (c) show colored light sequentially incident on the first and second image display elements 19 and 20, respectively.

_{At the timing when the fluorescent light Lphos} is emitted from the light source device 50, the light is incident on both the first and second image display elements 19 and 20. On the other hand, at the timing when the first color light L1 is emitted from the light source device 50, the light is incident only on the first image display element 19, and the light is not incident on the second image display element. That is, the second image display element 20 is not used for a long time, which is not preferable from the viewpoint of light utilization efficiency. The image projection apparatus of Patent Document 1 solves the above problem by incidenting blue light and green light generated by color-separating cyan light generated by exciting a cyan phosphor on two image display elements. However, a new problem arises that the white balance deteriorates.

In order to solve such a problem, in the present invention, the light source device 50 includes an auxiliary light source 11 that emits an auxiliary color light LS including a wavelength different from the wavelength of the first color light L1. The auxiliary light source 11 is composed of a plurality of laser light sources, and each light source emits green light having a main wavelength of 515 nm. As shown in FIG. 1 (b), the light flux emitted from each light source travels toward the positive lens 12 as a parallel light flux. The auxiliary color light LS is focused by the positive lens 12 and parallelized by the negative lens 13. The auxiliary light source 11 may be a light source having a spectral distribution narrower than the wavelength band of the second color light L2 and the third color light L3 such as an LED or a quantum dot.

The auxiliary color light LS emitted from the negative lens 13 is incident on the dichroic mirror 8 via the bending mirror 14. Since the dichroic mirror 8 has a spectral characteristic of transmitting light in a wavelength band of 470 nm or more, the auxiliary color light LS passes through the dichroic mirror 8 and is incident on the collimating lens 7. The auxiliary color light LS incident on the collimating lens is focused on the phosphor wheel 6.

In the present invention, the auxiliary color light LS is emitted from the light source device 50 at least a part of the time during which the first color light L1 is emitted from the light source device 50. That is, the auxiliary light source 11 is turned on at least a part of the time during which the first color light L1 is focused on the diffusion layer 6c. As shown in FIG. 1B, the auxiliary color light LS passes through the diffusion layer 6c from the collimating lens 7 side toward the condenser lens 5 side and is incident on the dichroic mirror 4. The auxiliary color light LS is transmitted from the dichroic mirror 4 and emitted from the light source device 50. As described above, the time when the auxiliary light color light LS is emitted is at least a part of the time when the first color light L1 is emitted. It's time.

The auxiliary color light LS emitted from the light source device 50 is incident on the color separation prism 18 via the illumination lens 15, the bending mirror 16, and the total reflection prism 17 in the same manner as the fluorescent light LS and the first color light L1. Since the color separation prism 18 has a spectral characteristic of reflecting green light in the wavelength band of 490 nm to 590 nm, the auxiliary color light LS is incident on the second image display element 20.

FIG. 4 is an explanatory diagram of the effect of this embodiment. FIG. 4A shows the light emitted from the light source device 50 over time. _{In this embodiment, the light source device 50 sequentially emits the fluorescent light Lphos} and the first color light L1 according to the rotation of the phosphor wheel 6, and also emits the auxiliary color light LS at the time when the first color light L1 is emitted. .. 4 (b) and 4 (c) show colored light sequentially incident on the first and second image display elements 19 and 20, respectively.

According to the configuration of this embodiment, _{at the timing when the fluorescent light Lphos} is emitted from the light source device 50, the light is incident on both the first and second image display elements 19 and 20. On the other hand, at the timing when the first color light L1 is emitted from the light source device 50, the first color light L1 is incident on the first image display element 19, and the auxiliary color light LS is incident on the second image display element 20. That is, it is preferable from the viewpoint of light utilization efficiency because it is possible to eliminate the unused time of the second image display element 20.

Further, since the first color light L1 is formed by the laser light itself emitted from the blue laser light source 1, the power density of the first color light L1 is high. _{Therefore, an appropriate white balance can be maintained even if the time for emitting the fluorescent light L phos} from the light source device 50 is set sufficiently longer than the time for emitting the first color light L1. In other words, the ratio of the phosphor layer 6b in the light irradiation region on the circumference of the phosphor wheel 6 can be sufficiently increased as compared with the ratio of the diffusion layer 6c. Specifically, it is desirable that the time ratio during which the first color light is emitted from the light source device 50 is 40% or less of the total time ratio during which the first color light and the fluorescent light are emitted.

Here, an example of a specific color balance correction method will be described with reference to FIG. FIG. 5 is an explanatory diagram of an example of the color balance correction method of this embodiment. 5 (a) and 5 (b) show the colored light and the image signal incident on the first and second image display elements 19 and 20, respectively. _{The second color light L2 separated from the fluorescent light L phos} and the first color light L1 are sequentially incident on the first image display element 19. _{The third color light L3 separated from the fluorescent light L phos} and the auxiliary color light LS are sequentially input to the second image display element 20. Image signals corresponding to the first color light L1 and the second color light L2 are input to the first image display element 19. An image signal corresponding to the third color light L3 is input to the second image display element 20. Further, at the timing when the auxiliary color light LS is input to the second image display element 20, an image signal corresponding to the third color light L3 is input as an image signal corresponding to the auxiliary color light LS.

In the example of FIG. 5, as the spectral distribution of light corresponding to the green component of the projected image, the third color light L3 of 490nm~590nm retrieved from the fluorescent light _{L phos,} narrowband auxiliary color lights of 515nm and dominant wavelength The spectral distribution of the light combined with the LS is acquired. By projecting the light obtained by synthesizing the auxiliary color light LS onto the third color light L3, the chromaticity coordinate of the green image becomes wider by the wavelength component having 515 nm as the main wavelength, as compared with the case where only the third color light L3 is projected. The color reproduction range can be expanded.

FIG. 6 is an explanatory diagram of another example of another color balance correction method of this embodiment. 6 (a) and 6 (b) show the colored light and the image signal incident on the first and second image display elements 19 and 20, respectively. In FIG. 6B, at the timing when the auxiliary color light LS is input, the image signal corresponding to the first color light L1 is input instead of the third color light L3 as the image signal corresponding to the auxiliary color light LS. Since the other configurations are the same as those in FIG. 5, the description thereof will be omitted.

In the example of FIG. 6, as the spectral distribution of the light corresponding to the green component in the projected image, the first color light L1 having the main wavelength of 450 nm of the blue laser light source 1 and the narrow band auxiliary color light LS having the main wavelength of 515 nm. A spectral distribution of light with two peaks combined with and is obtained. The chromaticity coordinates when the first color light L1 having the main wavelength of 450 nm of the blue laser light source 1 is a single blue color are slightly magnified with respect to the chromaticity coordinates of the blue image in the so-called sRGB chromaticity range. .. In this case, for example, when a blue image such as the sky is projected, the blue color of the sky becomes magenta-tinted, which is not preferable in terms of image quality. When a narrow band auxiliary color light LS having a main wavelength of 515 nm is combined with the first color light L1 having a main wavelength of 450 nm of the blue laser light source 1, blue in the sRGB chromaticity range is compared with the case where only the first color light L1 is projected. It can be brought closer to the chromaticity coordinates of the image. This makes it possible to project a more preferable image as a color balance.

As described above, in the example of FIG. 5, image signals corresponding to the first color light (blue light) L1 and the second color light (red light) L2 are sequentially input to the first image display element 19, and the second image. Image signals corresponding to the third color light (green light) L3 are continuously input to the display element 20. As a result, the color reproduction range of the green image can be expanded. In the example of FIG. 6, image signals corresponding to the first color light (blue light) L1 and the second color light (red light) L2 are sequentially input to the first image display element 19, and the second image display element 20 is the second. Image signals corresponding to the one-color light (blue light) L1 and the third-color light (green light) L3 are sequentially input. As a result, the wavelength components of the blue light and the auxiliary color light are combined in time, and the color balance of the blue image can be adjusted. Which correction method is used may be determined according to the image quality mode of the image projection device 100.

Further, in this embodiment, after the first color light L1 and the auxiliary color light LS are incident on the diffusion layer 6c, they are emitted in opposite directions. As a result, the auxiliary color light LS, the first color light L1 and the fluorescent light _Lphos can be emitted from the light source device 50 in the same direction, and the auxiliary color light LS emitted from the light source device 50 can be guided to the illumination optical system as coaxial. .. For example, when the auxiliary light LS is synthesized in the subsequent stage of the illumination lens 15 with a dichroic mirror or the like, the wavelength component of _{the fluorescent light Lphos corresponding to the narrow band portion of the auxiliary light LS is removed.} Therefore, with such a configuration, it is possible to efficiently adjust the color balance by the auxiliary color light LS.

The image projection device of the present embodiment basically has the same configuration as the image projection device of the first embodiment. In this embodiment, a configuration different from that of the first embodiment will be described.

In this embodiment, each light source of the auxiliary light source 11 emits red laser light having a main wavelength of 650 nm. Further, the color separation prism 18 has a spectral characteristic of transmitting blue light having a wavelength band of 430 nm to 480 nm and green light having a wavelength band of 490 nm to 590 nm and reflecting red light having a wavelength band of 600 to 700 nm.

FIG. 7 is an explanatory diagram of the effect of this embodiment. FIG. 7A shows the light emitted from the light source device 50 over time. _{As shown in FIG. 7A, fluorescent light Lphos} and first color light (blue light) L1 are sequentially emitted from the light source device 50 as the phosphor wheel 6 rotates. Further, the auxiliary color light LS is emitted at least a part of the time during which the first color light L1 is emitted from the light source device 50.

7 (b) and 7 (c) show the colored light incident on the first and second image display elements 19 and 20, respectively. The second color light (green light) L2 separated from _{the fluorescent light Lphos} and the first color light L1 are sequentially incident on the first image display element 19. The third color light (red light) L3 separated from _{the fluorescent light Lphos} and the auxiliary color light Ls are sequentially incident on the second image display element 20.

In this embodiment, as in the first embodiment, the unused time of the first image display element 19 can be eliminated, which is preferable from the viewpoint of light utilization efficiency. Further, since the first color light L1 is formed by the laser light itself emitted from the blue laser light source 1 _{, the time for emitting the fluorescent light Lphos} from the light source device 50 is compared with the time for emitting the first color light L1. Even if it is set long enough, an appropriate white balance can be maintained.

FIG. 8 is a diagram showing an example of a color balance correction method of this embodiment. 8 (a) and 8 (b) show the colored light and the image signal incident on the first and second image display elements 19 and 20, respectively. _{The second color light L2 separated from the fluorescent light L phos} and the first color light L1 are sequentially incident on the first image display element 19. _{The third color light L3 separated from the fluorescent light L phos} and the auxiliary color light LS are sequentially input to the second image display element 20. Image signals corresponding to the first color light L1 and the third color light L3 are input to the first image display element 19. An image signal corresponding to the second color light L2 is input to the second image display element 20. Further, at the timing when the auxiliary color light LS is input to the second image display element 20, an image signal corresponding to the second color light L2 is input as an image signal corresponding to the auxiliary color light LS.

As the wavelength component of the red light in the projected image, the wavelength component _{of the second color light L2 of 600 nm to 700 nm extracted from the fluorescent light Lphos} and the wavelength component of the narrow band having the auxiliary color light LS of 650 nm as the main wavelength are synthesized. Wavelength component is acquired. By projecting the light obtained by synthesizing the auxiliary color light LS onto the second color light L2, the chromaticity coordinate of the red image becomes wider by the wavelength component whose main wavelength is 650 nm, as compared with the case where only the second color light L2 is projected. The color reproduction range can be expanded.

As described above, the auxiliary color light LS may be red light instead of green light, and the second color light and the third color light may be red light and green light, respectively, depending on the spectral characteristics of the color separation prism 18. ..

FIG. 9 is a configuration diagram of an image projection device 200 equipped with the light source device 60 of this embodiment. In FIGS. 9A and 9B, the rotational positions of the phosphor wheel (wavelength conversion unit) 27 are different, and light of different colors is emitted from the light source device 60.

The image projection device 200 includes a light source device 60 and an illumination optical system. The light source device 60 includes a blue laser light source 21, an auxiliary light source 22, a positive lens 23, a negative lens 24, a partial dichroic mirror 25, a condenser lens 26, a phosphor wheel 27, a collimating lens 28, a relay lens system 29, and an optical path bending mirror. Has 30. The illumination optical system includes an illumination lens 31, a mirror 32, a total reflection prism 33, a color separation prism 34, a first image display element 35, and a second image display element 36.

The configuration of the present embodiment is different from the configuration of the first embodiment in that the auxiliary light source 22 that emits the auxiliary color light LS including the wavelength different from the wavelength of the first color light L1 is arranged between the blue laser light sources 21. Further, the configuration differs from that of the first embodiment in that the first color light L1 and the auxiliary color light LS are incident on the phosphor wheel 27 (diffusion layer 27c) from the same direction.

The blue laser light source 21 is composed of a plurality of light sources, and each light source emits blue light having a main wavelength of 450 nm. The luminous flux emitted from each light source travels toward the positive lens 23 as a parallel luminous flux. The first color light (blue light) L1 is focused by the positive lens 23 and parallelized by the negative lens 24. As a result, the width of the luminous flux is set to an appropriate size. The first color light L1 emitted from the negative lens 24 is incident on the partial dichroic mirror 25.

The auxiliary light source 22 is composed of a plurality of laser light sources, and each light source emits red light having a main wavelength of 650 nm. The luminous flux emitted from each light source travels toward the positive lens 23 as a parallel luminous flux. The auxiliary color light LS is focused by the positive lens 23 and parallelized by the negative lens 24. As a result, the width of the luminous flux is set to an appropriate size. The auxiliary color light LS emitted from the negative lens 24 is incident on the partial dichroic mirror 25.

FIG. 10 is a front view of the partial dichroic mirror 25. The partial dichroic mirror 25 is an element in which the first region 25a and the second region 25b are formed on the same flat plate, which have different spectral characteristics from each other. The power arrangement of the lens system of the positive lens 23 and the negative lens 24 and the blue laser light source 21 and the auxiliary light source so that the first color light L1 is incident on the first region 25a and the auxiliary color light LS is incident on the second region 25b. The arrangement of 22 is set.

FIG. 11 is a spectral characteristic diagram of the partial dichroic mirror 25. 11 (a) and 11 (b) show the spectral characteristics of the first region 25a and the second region 25b, respectively. The first region 25a has a spectral characteristic that reflects light in a wavelength band of 470 nm or less and transmits light in a wavelength band of 470 nm or more. The second region 25b has a spectral characteristic that reflects light in the wavelength band of 400 nm to 470 nm and light in the wavelength band of 640 to 700 nm and transmits light in the wavelength band of 470 nm to 640 nm. As a result, both the first color light L1 and the auxiliary color light LS are reflected by the partial dichroic mirror 25 and incident on the condenser lens 26. The first color light L1 and the auxiliary color light LS incident on the condenser lens 26 are focused on the phosphor wheel 27.

FIG. 12 is a block diagram of the phosphor wheel 27 of this embodiment. The phosphor wheel 27 sets at least a part of the light of the first color light L1 to a wavelength of the second color light L2 different from the wavelength of the first color light L1 and a wavelength of the third color light L3 different from the wavelengths of the first color light L1 and the second color light L2. Convert to include fluorescent light _Lphos. In the phosphor wheel 27, the phosphor layer 27b is formed on the circumference of the metal wheel 27a. A part of the region of the phosphor layer 27b is notched together with the metal wheel 27a, and a translucent diffusing layer (diffusing element) 27c is formed instead. Reference numeral 27d is a focusing spot of the first color light L1 focused on the phosphor wheel 27.

The first color light L1 is focused on the phosphor layer 27b at a certain time as shown in FIG. 12 (a). When the first color light L1 is focused on the phosphor layer 6b at the time corresponding to FIG. 12A, the phosphor absorbs the first color light L1 and is excited. The first color light L1 is converted into _{fluorescent light L phos} containing a wavelength component of 480 nm to 700 nm. Fluorescent light _Lphos is generated in all directions, but most of the components are reflected by the metal wheel 6a and travel toward the condenser lens 26.

When the phosphor wheel 27 rotates from the time corresponding to FIG. 12 (a), the first color light L1 is focused on the diffusion layer 27c at a certain time as shown in FIG. 12 (b). When the first color light L1 is focused on the diffusion layer 27c at the time corresponding to FIG. 12B, the region corresponding to the diffusion layer 27c of the metal wheel 27a is cut out, so that the first color light L1 Passes through the diffusion layer 27c and enters the collimating lens 28. The first color light L1 incident on the collimating lens 28 from the phosphor wheel 27 is incident on the partial dichroic mirror 25 via the relay lens system 29 and the optical path bending mirror 30, reflected by the partial dichroic mirror 25, and then on the illumination lens 31. Incident.

In this embodiment, unlike the first and second embodiments, a dichroic layer (optical element) 27e that transmits blue light and reflects the auxiliary color light LS is provided on the emission surface side of the first color light L1 of the diffusion layer 27c. ing. When the auxiliary light source 22 is turned on at the timing when the first color light L1 is incident on the diffusion layer 27c, the auxiliary color light LS is also incident on the diffusion layer 27c. The auxiliary color light LS is reflected by the dichroic layer 27e, travels in the direction opposite to that of the first color light L1, and is incident on the condenser lens 26.

The auxiliary color light LS is reflected by the dichroic layer 27e, but is reflected from the diffusion layer 27c with a larger light distribution than when it is incident because it is transmitted through the diffusion layer 27c. Therefore, the auxiliary color light LS is parallelized by the condenser lens 26 and is incident on the partial dichroic mirror 25 as a thick luminous flux straddling the first region 25a and the second region 25b. Of the auxiliary color light LS re-entering the partial dichroic mirror 25, the component incident on the second region 25b is reflected and returned to the side of the auxiliary light source 22, but the component incident on the first region 25a is transmitted and transmitted to the illumination lens 31. Incident in.

In this embodiment, the first color light L1 and the auxiliary color light LS are incident on the diffusion layer 27c from the same direction and emitted in opposite directions. Therefore, as in Examples 1 and 2, a compression lens system for the auxiliary light source 22. And there is no need to place a mirror. With such a configuration, the auxiliary color light LS, the first color light L1 and the fluorescent light _Lphos can be emitted from the light source device 60 in the same direction, and the auxiliary color light LS emitted from the light source device 60 is coaxially guided to the illumination optical system. Therefore, the light source device 60 can be miniaturized. Further, since the blue laser light source 21 and the auxiliary light source 22 are arranged at the same place, a common cooling device can be used, and the light source device 60 can be further miniaturized.

Since the optical path and configuration in which the first color light L1, the fluorescent light _Lphos, and the auxiliary color light LS travel from the light source device 60 to the illumination optical system and the method for obtaining the effect of the invention are the same as those in the second embodiment, the description thereof will be omitted.

In this embodiment, the auxiliary light source 22 is a red laser light source, but a green laser light source may be used by changing the color separation configuration of the color separation prism. Further, the color balance can be appropriately set by inputting an image signal corresponding to red, green, or blue to the second image display element 20 according to the purpose.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and modifications can be made within the scope of the gist thereof.

L1 First color light L2 Second color light L3 Third color light L _phos Fluorescent light LS Auxiliary color light 1,21 Blue laser light source (first light source)
6,27 Fluorescent wheel (wavelength converter)
11,22 Auxiliary light source (second light source)
19 First image display element 20 Second image display element 50, 60 Light source device

Claims (12)

The first light source that emits the first color light and
A wavelength conversion unit that converts at least a part of the first color light into fluorescent light including a second color light having a wavelength different from that of the first color light and a third color light having a wavelength different from that of the first and second color light. ,
A light source device having a second light source that emits auxiliary color light including a wavelength different from the wavelength of the first color light, and sequentially emitting the first color light and the fluorescent light.
The second color light separated from the first color light and the fluorescent light is incident on the first image display element, and is incident on the first image display element.
The third color light separated from the fluorescent light is incident on the second image display element, and the third color light is incident on the second image display element.
The light source device, characterized in that the auxiliary color light is incident on the second image display element at least a part of the time during which the first color light is emitted. The light source according to claim 1, wherein the time ratio during which the first color light is emitted is 40% or less with respect to the total time ratio during which the first color light and the fluorescent light are emitted. apparatus. The light source device according to claim 1 or 2, wherein the wavelength band of the auxiliary color light is narrower than the wavelength band of the second color light or the third color light. The wavelength conversion unit includes a diffusing element that diffuses the first color light and the auxiliary color light.
The light source device according to any one of claims 1 to 3, wherein the first color light and the auxiliary color light are emitted in opposite directions after being incident on the diffusing element. The light source device according to claim 4, wherein the first color light and the auxiliary color light are incident on the diffusion element from opposite directions. The light source device according to claim 4, wherein the first color light and the auxiliary color light are incident on the diffusion element from the same direction. The light source according to claim 6, wherein the wavelength conversion unit includes an optical element that transmits the first color light and reflects the auxiliary color light on the side of the emission surface of the first color light of the diffusion element. apparatus. A first light source that emits first color light, a second color light that emits at least a part of the first color light with a wavelength different from that of the first color light, and a third color light wavelength different from the wavelengths of the first and second color lights. A light source device that includes a wavelength conversion unit that converts the first color light into fluorescent light and a second light source that emits auxiliary color light including a wavelength different from the wavelength of the first color light, and sequentially emits the first color light and the fluorescent light. ,
A first image display element to which the second color light separated from the first color light and the fluorescent light is incident, and
It has a second image display element on which the third color light separated from the fluorescent light is incident.
An image projection device characterized in that the auxiliary color light is incident on the second image display element at least a part of the time during which the first color light is emitted. Image signals corresponding to the first and second color lights are sequentially input to the first image display element.
The image projection device according to claim 8, wherein image signals corresponding to the third color light and the auxiliary color light are sequentially input to the second image display element. The image projection device according to claim 9, wherein the image signal corresponding to the auxiliary color light is an image signal corresponding to the third color light. The image projection device according to claim 9, wherein the image signal corresponding to the auxiliary color light is an image signal corresponding to the first color light. The image projection apparatus according to any one of claims 9 to 11, further comprising a projection optical system for projecting an image based on light from the first and second image display elements onto a projected surface. ..

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