Light source device and image projection device

Abstract

To provide a light source device and an image projection device with which, while being provided with a plurality of light sources, it is possible to reduce the device size.SOLUTION: Provided is a light source device comprising: a first light source for emitting light of a first color; a second light source for emitting light of a second color; a wavelength conversion unit for converting at least a portion of light of the first color to light of a third color and emitting it; a light incidence element which the light of the first, second and third colors enters; a first filter for reflecting light of the first color toward the wavelength conversion unit; and a second filter for reflecting light of the second color toward the light incidence element. The first and the second filters are arranged separately from each other in the optical path of light of the third color between the wavelength conversion unit and the light incidence element.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a light source device and an image projection device. [Background technology]

[0002] Nowadays, projectors (image projection devices) that enlarge and project various images are widely used. A projector focuses light emitted from a light source onto a spatial light modulator such as a digital micromirror device (DMD) or a liquid crystal display element, and displays the emitted light from the spatial light modulator modulated by a video signal on a screen as a color image.

[0003] In a projector, an image is formed by irradiating an image display element such as a DMD with three primary colors, red, green, and blue. Although it is possible to generate all three colors with a laser light source, the emission efficiency of red and green lasers is lower than that of blue lasers, so the most common method is to irradiate a phosphor with blue laser as excitation light, and generate red and green light from the fluorescent light that is wavelength-converted by the phosphor.

[0004] On the other hand, the spectral width of fluorescent light is very wide, which causes a problem of poor color reproducibility compared to the case of using a laser light source. For this reason, it has been proposed recently to combine fluorescent light with red / green laser light in order to achieve both brightness and color reproducibility by reinforcing the red component of fluorescent light with red laser light and the green component with green laser light (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] China Patent Application Publication No. 110083003 Summary of the Invention [Problem to be solved by the invention]

[0006] However, when fluorescent light is combined with red / green laser light, the spectra of the fluorescent light and red / green light overlap, so that when the fluorescent light is combined with the red / green laser light, a part of the fluorescent light is cut off (vignetted), and the light utilization efficiency of the fluorescent light is reduced. In addition, the addition of multiple light sources corresponding to the red / green laser light and the restrictions on the arrangement of the multiple light sources cause a problem of an increase in the size of the device.

[0007] The present invention has been completed based on the above-mentioned awareness of the problems, and has an object to provide a light source device and an image projection device that are provided with a plurality of light sources and can be made compact. [Means for solving the problem]

[0008] The light source device of this embodiment includes a first light source that emits a first color light, a second light source that emits a second color light, a wavelength conversion unit that converts at least a part of the first color light into a third color light and emits the third color light, a light entrance element on which the first, second, and third color lights are incident, a first filter that reflects the first color light to the wavelength conversion unit, and a second filter that reflects the second color light to the light entrance element, and the first and second filters are separately disposed on an optical path of the third color light between the wavelength conversion unit and the light entrance element. a central axis of the first color light emitted from the first light source and a central axis of the second color light emitted from the second light source extend in a twisted relationship with each other on an optical path of the third color light between the wavelength conversion unit and the light incident element; It is characterized by: The light source device of this embodiment includes a first light source that emits a first color light, a second light source that emits a second color light, a wavelength conversion unit that converts at least a portion of the first color light into a third color light and emits it, a light entrance element into which the first, second, and third color lights are incident, a first filter that reflects the first color light to the wavelength conversion unit, and a second filter that reflects the second color light to the light entrance element, and is characterized in that the first and second filters are separately disposed on the optical path of the third color light between the wavelength conversion unit and the light entrance element, and the first, second, and third color lights are not located in the same plane. Effect of the Invention

[0009] According to the present invention, it is possible to provide a light source device and an image projection device that are provided with a plurality of light sources and can be made compact. [Brief description of the drawings]

[0010] [Figure 1] 2 is a diagram for explaining the definitions of the optical axis of a lens, the optical axis of a light source, and the center of a projection image. FIG. [Diagram 2] 1 is a diagram showing a configuration of a light source device according to a first embodiment. [Diagram 3]FIG. 2 is a diagram illustrating an example of the configuration of a wavelength conversion unit. [Figure 4] FIG. 11 is a diagram illustrating an example of the reflection characteristics of a second filter. [Diagram 5] FIG. 4 is a diagram showing an example of the spectrum of all light incident on a light homogenizing element. [Figure 6] 13 is a diagram showing the spots of red laser light and fluorescent light on the second collecting lens superimposed on the second filter. FIG. [Figure 7] FIG. 13 is a diagram showing a configuration of a light source device according to a second embodiment. [Figure 8] FIG. 4 is a diagram showing an example of the arrangement of first and second filters. [Figure 9] FIG. 11 is a first diagram showing the configuration of a light source device according to a third embodiment. [Figure 10] FIG. 13 is a second diagram showing the configuration of the light source device according to the third embodiment. [Figure 11] FIG. 13 is a first diagram showing the configuration of a light source device according to a fourth embodiment. [Figure 12] FIG. 13 is a second diagram showing the configuration of the light source device according to the fourth embodiment. [Figure 13] 13 is a diagram showing a configuration of a light source device according to a fifth embodiment. FIG. [Figure 14] FIG. 13 is a diagram showing a configuration of a light source device of a comparative example. [Figure 15] FIG. 1 is a diagram showing a configuration of a projector according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] <Terminology> Fig. 1A is a diagram for explaining the definition of the optical axis of a lens. As shown in Fig. 1A, the optical axis of a lens means a virtual straight line that coincides with the rotational symmetry axis of the lens. The optical axis may also be read as the central axis.

[0012] Fig. 1B is a diagram for explaining the definition of the optical axis of a light source. As shown in Fig. 1B, the optical axis of a light source means a straight line perpendicularly connecting the light emitting surface of the light source and the center of the projected image of the optical element arranged immediately behind the light source. The optical axis may also be read as the central axis.

[0013] In addition to the definitions in FIG. 1A and FIG. 1B, the term "optical axis" in this specification refers to a virtual line including a virtual light ray that is representative of the light beam passing through the entire system in a certain optical system. In the case of an optical system consisting of a plurality of optical elements, the optical axis may be located on a virtual line that approximately coincides with the rotational symmetry axis of each optical element, depending on the design of the optical system. In addition, in one optical element, for example, a straight line connecting the centers of curvature of the two front and rear surfaces may coincide with the optical axis. In addition, if one of the two front and rear surfaces of one optical element is flat, a straight line passing through the center of curvature of the other surface having a curvature may coincide with the optical axis. In addition, in an optical system in which a plurality of optical elements are arranged, a virtual line approximately connecting the centers of curvature of the curved surfaces constituting each optical element may coincide with the optical axis. It goes without saying that the light (light beam) actually used does not necessarily pass along the optical axis.

[0014] Fig. 1C is a diagram for explaining the definition of the center of a projected image. As shown in Fig. 1C, the center of a projected image means the center of the smallest circumscribed circle of the light intensity distribution in the projection range of a light source, which is projected onto an optical element disposed immediately behind the light source.

[0015] In this specification, the first color light means (may be read as) a first light in a first wavelength range, the second color light means (may be read as) a second light in a second wavelength range, and the third color light means (may be read as) a third light in a third wavelength range. The first, second, and third color lights mean (may be read as) lights in a plurality of wavelength ranges. The first, second, and third wavelength ranges mean different wavelength ranges, but some of the wavelength ranges may overlap. For example, the first color light may be blue light, the second color light may be red light or green light, and the third color light may be yellow or green fluorescent light. By setting the second and third color lights in this way, for example, the red and green components of the fluorescent light can be reinforced by the red and green lights, so that a light source device with good color reproducibility can be realized.

[0016] First Embodiment 2 is a diagram showing the configuration of the light source device 1 of the first embodiment. In the following description, the X-axis, Y-axis, and Z-axis directions are based on the arrow directions shown in the figure, with the direction in which the arrows (arrows) point being the + direction and the direction in which the arrows (arrows) do not point being the - direction. The X-axis, Y-axis, and Z-axis directions form a three-dimensional space that is orthogonal to one another.

[0017] The light source device 1 has a blue laser light source (first light source) 10, a red laser light source (second light source) 20, a blue laser reduction element 30, a red laser reduction element 40, a first filter (first optical element, first dichroic mirror, first notch filter) 50, a second filter (second optical element, second dichroic mirror, second notch filter) 60, a first focusing lens (first focusing element, focusing optical system) 70, a wavelength conversion unit (phosphor unit) 80, a second focusing lens (second focusing element, focusing optical system) 90, and a light homogenizing element (light entrance element) 100.

[0018] The blue laser light source 10, the red laser light source 20, the blue laser reduction element 30, the red laser reduction element 40, the first filter 50, the second filter 60, the first focusing lens 70, the wavelength conversion unit 80, the second focusing lens 90, and the light homogenizing element 100 are positioned in the same plane including the X-axis and Y-axis directions with their positions aligned in the Z-axis direction (at least a portion of them is positioned in the same plane).

[0019] The blue laser light source 10, the blue laser reduction element 30, and the first filter 50 are arranged in order from the + side to the - side in the X-axis direction at a position on the - side in the Y-axis direction. The red laser light source 20, the red laser reduction element 40, and the second filter 60 are arranged in order from the - side to the + side in the X-axis direction at a position on the + side in the Y-axis direction.

[0020] The first condensing lens 70, the wavelength conversion unit 80, the second condensing lens 90, and the light homogenizing element 100 are aligned in the Y-axis direction with their positions in the X-axis direction being the same. More specifically, the first condensing lens 70 and the wavelength conversion unit 80 are aligned in order toward the negative side of the first filter 50 in the Y-axis direction. Moreover, the second condensing lens 90 and the light homogenizing element 100 are aligned in order toward the positive side of the second filter 60 in the Y-axis direction.

[0021] Blue laser light source 10 emits blue laser light (blue light, first colored light) toward the negative side in the X-axis direction. The blue laser light may be light of a wavelength that has a center of emission intensity of 455 nm, for example, and that can provide an excitation effect in wavelength conversion unit 80. In FIG. 1, blue laser light source 10 is depicted as having a plurality of light emission sources arranged in an array, but is not limited thereto, and blue laser light source 10 may be composed of a single (one) light emission source. In FIG. 1, the luminous flux of the blue laser light is depicted by a bold dashed line, and the optical axis of the blue laser light is indicated by 10A.

[0022] Blue laser reduction element 30 has positive lens 31 and negative lens 32. Positive lens 31 converges the blue laser light from blue laser light source 10, and negative lens 32 diverges the blue laser light from blue laser light source 10, resulting in the blue laser light from blue laser light source 10 being approximately parallelized (collimated). The luminous flux of the blue laser light approximately parallelized by blue laser reduction element 30 is preferably designed (adjusted) in accordance with the size of first filter 50.

[0023] The first filter 50 reflects the blue laser light, which has been approximately collimated by the blue laser reduction element 30, toward the negative side in the Y-axis direction, and guides it to the first focusing lens 70 and further to the wavelength conversion unit 80. The first filter 50 has the property of, for example, reflecting only blue light and transmitting fluorescent light.

[0024] The red laser light source 20 emits red laser light (red light, second color light) toward the positive side in the X-axis direction. The red laser light may be light having a wavelength that can achieve a desired color reproducibility, for example, with a center of emission intensity of 610 nm. In FIG. 1, the red laser light source 20 is depicted as having a plurality of light emission sources arranged in an array, but is not limited thereto, and the red laser light source 20 may be composed of a single (one) light emission source. In FIG. 1, the light beam of the red laser light is depicted by a bold dashed line, and the optical axis of the red laser light is indicated by 20A. Note that, although the present embodiment illustrates an example in which red laser light from the red laser light source 20 is synthesized, it is also possible to synthesize green laser light and laser light having other wavelength ranges (colors). In this case, it is preferable to change the characteristics of the second filter 60 at the same time.

[0025] The red laser reduction element 40 has a positive lens 41 and a negative lens 42. The positive lens 41 converges the red laser light from the red laser light source 20, and the negative lens 42 diverges the red laser light from the red laser light source 20, resulting in the red laser light from the red laser light source 20 being approximately parallelized (collimated). The light flux of the red laser light approximately parallelized by the red laser reduction element 40 is preferably designed (adjusted) in accordance with the size of the second filter 60.

[0026] The second filter 60 has the property of reflecting red light, and reflects the red laser light that has been approximately collimated by the red laser reduction element 40 toward the positive side of the Y-axis direction, and guides it to the second focusing lens 90 and further to the light homogenizing element 100.

[0027] The first condensing lens 70 condenses the blue laser light from the first filter 50 and guides it to the wavelength conversion unit 80. The first condensing lens 70 also approximately collimates the blue laser light and the fluorescent light (third colored light) from the wavelength conversion unit 80 and guides them to the + side in the Y-axis direction.

[0028] The first condensing lens 70 is located between the first filter 50 and the wavelength conversion unit 80, and functions as a "first condensing element" that condenses the blue laser light reflected by the first filter 50 and approximately parallelizes the blue laser light and fluorescent light emitted by the wavelength conversion unit 80. The blue laser light is incident on the wavelength conversion unit 80 through a part (the region on the positive side in the X-axis direction) of the first condensing lens (first condensing element) 70, reflected by a reflection region 83 described later, and then emitted through another part (the region on the negative side in the X-axis direction) of the first condensing lens (first condensing element) 70. This allows the blue laser light for exciting the phosphor to be used as illumination light, so that white light can be generated by combining it with the fluorescent light.

[0029] The wavelength conversion unit 80 reflects the blue laser light from the first condenser lens 70 as it is and guides it to the first condenser lens 70, and also converts the blue laser light from the first condenser lens 70 into fluorescent light (third color light) and guides it to the first condenser lens 70. In other words, the wavelength conversion unit 80 converts a part (at least a part) of the blue laser light from the first condenser lens 70 into fluorescent light and emits it.

[0030] FIG. 3 is a diagram showing an example of the configuration of the wavelength conversion unit 80. As shown in FIG. 3, the wavelength conversion unit 80 is configured as a disk member that can rotate around a rotation axis 82 along the Y-axis direction by a drive mechanism 81 (FIG. 2) including a motor unit. The wavelength conversion unit 80 is partitioned into a reflection region 83 located in a part (small part) in the circumferential direction and a fluorescent region 84 located in the other part (most part) in the circumferential direction. When the wavelength conversion unit 80 rotates around the rotation axis 82, the blue laser light is alternately incident on the reflection region 83 and the fluorescent region 84. The blue laser light incident on the reflection region 83 is reflected by the reflection region 83 and guided to the first condenser lens 70. The blue laser light incident on the fluorescent region 84 is acted on as excitation light in the fluorescent region 84, converted into fluorescent light (third color light) in a wavelength range different from the blue laser light, and then guided to the first condenser lens 70. In this way, the wavelength conversion unit 80 can temporally switch between a function of reflecting the blue laser light and guiding it to the first focusing lens 70 and a function of converting the blue laser light into fluorescent light and guiding it to the first focusing lens 70.

[0031] 3, the wavelength conversion unit 80 is divided into the reflection region 83 and the fluorescent region 84, but for example, a yellow fluorescent region and a green fluorescent region may be provided to divide the fluorescent region into two or more regions. The wavelength conversion unit 80 is not limited to a unit that rotates and emits light in a time-division manner, but may be any unit that has a function of reflecting blue laser light and a function of converting fluorescent light.

[0032] In Fig. 1, the fluorescent light beam is depicted by a grayscale filled area, and the optical axis of the fluorescent light is indicated by 80 A. As shown in Fig. 1, the range (grayscale) of the fluorescent light beam includes the blue laser light beam (bold dashed line) and the red laser light beam (bold dashed dot line).

[0033] The second condenser lens 90 condenses the red laser light (second color light) incident from the second filter 60, and the blue laser light (first color light) and the fluorescent light (third color light) incident from the wavelength conversion unit 80 and the first condenser lens 70, and guides them to the light homogenizing element 100. In Fig. 1, the optical axis of the second condenser lens 90 is indicated by 90A.

[0034] The light homogenizing element 100 is composed of, for example, a light tunnel formed so that four mirrors are inside a rectangular prism. The light homogenizing element 100 has a function of homogenizing the blue laser light (first color light), the red laser light (second color light), and the fluorescent light (third color light) incident from the second condenser lens 90 and emitting the homogenized light.

[0035] The optical paths of the blue laser light (first colored light), the red laser light (second colored light), and the fluorescent light (third colored light) will be described.

[0036] The blue laser light is emitted from the blue laser light source 10, and the light flux is narrowed by the blue laser reduction element 30 to become approximately parallel light, and is reflected by the first filter 50. The blue laser light is incident on the negative half of the first focusing lens 70 in the X-axis direction, approaches the optical axis at an angle due to the refractive power of the first focusing lens 70, is focused near the optical axis of the first focusing lens 70, and is incident on the wavelength conversion unit 80. The blue laser light is reflected by the reflection region 83 of the wavelength conversion unit 80, and is incident on the positive half of the first focusing lens 70 in the X-axis direction, moves away from the optical axis at an angle due to the refractive power of the first focusing lens 70, and becomes approximately parallel light. The blue laser light then enters the positive half of the second focusing lens 90 in the X-axis direction, approaches the optical axis at an angle due to the refractive power of the second focusing lens 90, is focused near the optical axis, and enters the light homogenizing element 100 positioned near the focusing position.

[0037] Red laser light is emitted from red laser light source 20, and the light flux is narrowed by red laser reduction element 40 to become approximately parallel light, and is reflected by second filter 60. Then, the red laser light is incident on the positive half of second focusing lens 90 in the X-axis direction, approaches the optical axis at an angle due to the refractive power of second focusing lens 90, is focused near the optical axis, and is incident on light homogenizing element 100 arranged near the focusing position.

[0038] The fluorescent light is generated by exciting the blue laser light in the fluorescent region 84 of the wavelength conversion unit 80. The fluorescent light is approximately collimated by the first focusing lens 70. The negative portion of the fluorescent light in the X-axis direction passes through the first filter 50, is focused by the second focusing lens 90, and enters the light uniformizing element 100 arranged near the focusing position. The positive portion of the fluorescent light in the X-axis direction passes through the second filter 60 (part of which is reflected, as described below), is focused by the second focusing lens 90, and enters the light uniformizing element 100 arranged near the focusing position.

[0039] In the light source device 1 of this embodiment, the first filter 50 and the second filter 60 are separately arranged on the optical path (gray scale) of the fluorescent light (third color light) between the wavelength conversion unit 80 and the light homogenizing element 100. This improves the degree of freedom in the layout of the blue laser light source 10 and the red laser light source 20, and the first filter 50 and the second filter 60, and allows the light source device 1 to be miniaturized. In addition, by improving the degree of freedom in the layout of the first filter 50 and the second filter 60, the light loss caused by the first filter 50 and the second filter 60 in the optical path of the fluorescent light (third color light) is minimized, and the light utilization efficiency can be improved.

[0040] By aligning the positions of the set of the blue laser light source 10, the blue laser reduction element 30, and the first filter 50, and the set of the red laser light source 20, the red laser reduction element 40, and the second filter 60 in the Z-axis direction, shifting their positions in the Y-axis direction, and overlapping them in the X-axis direction, the light source device 1 can be made even smaller.

[0041] The first condensing lens 70 and the second condensing lens 90 form a "condensing optical system" located between the wavelength conversion unit 80 and the light homogenizing element 100, and the first filter 50 and the second filter 60 are arranged off the optical axis of the condensing optical system. In particular, the second filter 60 is arranged off the optical axis of the second condensing lens (condensing optical system) 90. Since the intensity of the fluorescent light (third color light) is strongest near the optical axis of the condensing optical system, the first filter 50 and the second filter 60 (particularly the second filter 60) are arranged away from the optical axis of the condensing optical system, thereby improving the efficiency of use of the fluorescent light.

[0042] The optical axis (center axis) 10A of the blue laser light (first color light) emitted from the blue laser light source (first light source) 10 and the optical axis (center axis) 20A of the red laser light (second color light) emitted from the red laser light source (second light source) 20 are different from each other. Specifically, the optical axis (center axis) 10A and the optical axis (center axis) 20A are located in the same plane including the X-axis direction and the Y-axis direction, and extend parallel to each other (extend in the X-axis direction) on the optical path (gray scale) of the fluorescent light (third color light) between the wavelength conversion unit 80 and the light homogenizing element 100. By disposing the blue laser light source 10, the red laser light source 20, and the cooling devices (heat sinks) of each laser light source in parallel with a shift in the Y-axis direction, it is possible to prevent the light source device 1 from becoming large in the X-axis direction. In addition, it is possible to increase the cooling efficiency of the laser light source by the cooling device.

[0043] The first filter 50 and the second filter 60 are provided so that there is no component of the fluorescent light (third color light) that passes through both the first filter 50 and the second filter 60. This makes it possible to prevent a decrease in the utilization efficiency of only a portion of the fluorescent light, and to suppress color unevenness in the fluorescent light.

[0044] The second filter 60 transmits the wavelength range of the fluorescent light (third color light) excluding the wavelength range of the red laser light (second color light) (reflects only the red component). In this way, by providing the second filter 60 with wavelength selectivity resulting in a narrow band reflection spectrum, the utilization efficiency of the fluorescent light can be improved.

[0045] Fig. 4 is a diagram showing an example of the reflection characteristic of the second filter 60. For example, when using a red laser light (red laser light source 20) with a peak at 640 nm, as shown in Fig. 4, the reflectance of the second filter 60 can be set to 96% or more in the range of 620 nm to 660 nm.

[0046] Fig. 5 is a diagram showing an example of the spectrum of all light incident on the light homogenizing element 100. In Fig. 5, the spectra of blue laser light, red laser light, and fluorescent light are depicted. Although the light utilization efficiency is reduced because the portion of the fluorescent light corresponding to the red laser light passes through the second filter 60, it can be seen that the reduction in light utilization efficiency is suppressed by optimizing the reflection characteristics, size, and arrangement of the second filter 60.

[0047] The amount of red laser light (second color light) reflected by the second filter 60 is greater than the amount of fluorescent light (third color light) reflected by the second filter 60. In the second filter 60, by making the amount of combined red laser light greater than the amount of lost fluorescent light, it is possible to improve color reproducibility while maintaining brightness.

[0048] 6A, 6B, and 6C are diagrams showing the spots of the red laser light and the fluorescent light in the second collecting lens 90 superimposed on the second filter 60. Figs. 6A to 6C show the positional relationship when viewed from the - side in the Y-axis direction, and components that will not be described are omitted from the illustration.

[0049] 6A to 6C, the optical axis 90A of the second collecting lens 90 is a virtual straight line that coincides with the axis of rotational symmetry of the second collecting lens 90. The spot of the fluorescent light in the second collecting lens 90 is formed in a wide range across almost the entire effective optical surface, centered on the optical axis 90A of the second collecting lens 90. In contrast, the spot of the red laser light in the second collecting lens 90 is located to the left of the optical axis 90A of the second collecting lens 90, and falls within the range of the reflecting surface of the imaginary second filter 60.

[0050] In this way, by making the spot of the red laser light on the second condenser lens 90 smaller than the spot of the fluorescent light on the second condenser lens 90, it is possible to improve the efficiency of using the fluorescent light.

[0051] More specifically, when the projected area of ​​the fluorescent light (third color light) on the second focusing lens (second focusing element) 90 is PSA3 and the projected area of ​​the red laser light (second color light) on the second focusing lens (second focusing element) 90 is PSA2, it is preferable to satisfy conditional formula (1). (1) 0.100≦PSA2 / PSA3≦0.375

[0052] By satisfying conditional expression (1), the red light beam can be narrowed and the second filter 60 can be made smaller, thereby reducing costs, improving the efficiency of use of the fluorescent light, and preventing color unevenness in the red light. If the upper limit of conditional expression (1) is exceeded, the red light beam becomes too wide and the second filter becomes too large, which makes it unavoidable to increase costs and significantly reduces the efficiency of use of the fluorescent light. If the lower limit of conditional expression (1) is exceeded, it is necessary to narrow the red laser light, which causes color unevenness in the red light.

[0053] In Fig. 6A, the entire area of ​​the second filter 60 contributes to the reflection of the red laser light, but when the second filter 60 is held outside the fluorescent light spot, it is also possible to form the second filter 60 in a filter formation portion (filter non-formation portion) that does not contribute to the reflection of the fluorescent light, as shown in Fig. 6B and Fig. 6C. In Fig. 6B, the second filter 60 is extended to the outside of the fluorescent light spot (the left side in the figure), and the portion that overlaps with the fluorescent light spot does not contribute to reflection. Part 6 1. The portion that does not overlap with the phosphor spot is a non-reflection contributing portion (a portion where a filter is formed, a portion where a filter is not formed) 62. In Fig. 6C, the second filter 60 is formed on a glass substrate 63 as a separate member, and the glass substrate 63 extends to the outside of the fluorescent light spot (the left side in the figure). The glass substrate 63 corresponds to the non-reflection contributing portion (a portion where a filter is formed, a portion where a filter is not formed).

[0054] Furthermore, since the amount of fluorescent light is generally greatest near the optical axis 90A of the second focusing lens (second focusing element) 90, positioning the spot of the red laser light so that it does not overlap with the optical axis 90A of the second focusing lens 90, in other words, positioning the second filter 60 so that it does not overlap with the optical axis 90A of the second focusing lens 90, can suppress a decrease in the light utilization efficiency of the fluorescent light.

[0055] <Second embodiment> A light source device 1 of the second embodiment will be described with reference to Fig. 7 and Fig. 8. Fig. 7 is a diagram showing the configuration of the light source device 1 of the second embodiment. Figs. 8A and 8B are diagrams showing an example of the arrangement of the first filter 50 and the second filter 60. Descriptions of overlapping parts with the light source device 1 of the first embodiment will be omitted.

[0056] In the light source device 1 of the second embodiment, the set of the blue laser light source 10, the blue laser reduction element 30, and the first filter 50, and the set of the red laser light source 20, the red laser reduction element 40, and the second filter 60 are arranged side by side in the X-axis direction with their Y-axis positions aligned. The set of the blue laser light source 10, the blue laser reduction element 30, and the first filter 50 is located on the + side in the X-axis direction, and the set of the red laser light source 20, the red laser reduction element 40, and the second filter 60 is located on the - side in the X-axis direction. The first filter 50 and the second filter 60 are arranged back to back with the backs of their reflective surfaces facing each other.

[0057] Since the first filter 50 and the second filter 60 are arranged so as to overlap part of the optical path (grayscale) of the fluorescent light (third color light) between the wavelength conversion unit 80 and the light homogenizing element 100, the area on the optical path of the fluorescent light that is not passed through the filter is increased, thereby improving the utilization efficiency of the fluorescent light.

[0058] As shown in FIG. 8A and FIG. 8B, the first filter 50 is provided on one surface of a substrate 50A made of glass or the like, and the second filter 60 is provided on one surface of a substrate 60A made of glass or the like. FIG. 8A shows an example in which the back surface of the substrate 50A on which the first filter 50 is not formed and the back surface of the substrate 60A on which the second filter 60 is not formed are opposed to each other with a gap therebetween. FIG. 8B shows an example in which the back surface of the substrate 50A on which the first filter 50 is not formed and the back surface of the substrate 60A on which the second filter 60 is not formed are bonded together. In the embodiment of FIG. 8B relating to the bonding, the loss of light at the interface between the substrates 50A and 60A can be reduced, and the decrease in the efficiency of use of fluorescent light can be suppressed.

[0059] <Third embodiment> A light source device 1 of the third embodiment will be described with reference to Fig. 9 and Fig. 10. Fig. 9 and Fig. 10 are first and second diagrams showing the configuration of the light source device 1 of the third embodiment. Fig. 9 is a diagram seen from the - side in the Z axis direction, and Fig. 10 is a diagram seen from the - side in the X axis direction. Descriptions of parts that overlap with the light source devices 1 of the first and second embodiments will be omitted.

[0060] In the light source device 1 of the third embodiment, the blue laser light (first color light), the red laser light (second color light), and the fluorescent light (third color light) are not positioned on the same plane (are arranged three-dimensionally). Also, the optical axis (center axis) 10A of the blue laser light (first color light) emitted from the blue laser light source (first light source) 10 and the optical axis (center axis) 20A of the red laser light (second color light) emitted from the red laser light source (second light source) 20 extend in a twisted relationship with each other on the optical path (gray scale) of the fluorescent light (third color light) between the wavelength conversion unit 80 and the light homogenizing element 100.

[0061] In other words, the light source device 1 of the third embodiment corresponds to the light source device 1 of the first embodiment, in which a set of a red laser light source 20, a red laser reduction element 40, and a second filter 60 is rotated 90 degrees along a rotation axis in the Y-axis direction.

[0062] In addition, in the light source device 1 of the third embodiment, a blue laser heat sink 10B is provided on the back surface of the blue laser light source 10, and a red laser heat sink 20B is provided on the back surface of the red laser light source 20. However, the blue laser heat sink 10B and the red laser heat sink 20B may also be provided in the light source device 1 of the first embodiment.

[0063] According to the light source device 1 of the third embodiment, the blue laser light source 10 and the red laser light source 20, and thus the blue laser light and the red laser light, are arranged three-dimensionally, thereby further increasing the freedom in arranging the light sources and making it possible to miniaturize the entire optical system.

[0064] In the light source device 1 of the third embodiment, the optical axis of the red laser light source 20 is rotated 90° relative to the optical axis of the blue laser light source 10, and the second filter 60 is also rotated 90° accordingly. This allows the light source device 1 to be made compact in the X-axis direction. Also in the Z-axis direction, the red laser light source 20 is disposed in the space created by the wavelength conversion unit 80 (the red laser light source 20 does not protrude from the wavelength conversion unit 80 in the Z-axis direction), resulting in an optical configuration that fits well overall.

[0065] In the light source device 1 of the third embodiment, the optical axis of the red laser light source 20 is rotated 90° relative to the optical axis of the blue laser light source 10, but this rotation angle is not limited to 90° and can be changed (determined) arbitrarily depending on, for example, the design of the heat sink (cooling device), etc.

[0066] <Fourth embodiment> A light source device 1 of the fourth embodiment will be described with reference to Fig. 11 and Fig. 12. Fig. 11 and Fig. 12 are first and second diagrams showing the configuration of the light source device 1 of the fourth embodiment. Fig. 11 is a diagram seen from the - side in the Z-axis direction, and Fig. 12 is a diagram seen from the - side in the X-axis direction. Descriptions of parts that overlap with the light source devices 1 of the first to third embodiments will be omitted.

[0067] The light source device 1 of the fourth embodiment is the light source device 1 of the third embodiment, in which the optical axis (central axis) 10A of the blue laser light (first colored light) and the optical axis (central axis) 80A of the fluorescent light (third colored light) are shifted in the Z-axis direction (the shift in the Z-axis direction between the optical axis 10A and the optical axis 80A can be seen by comparing FIG. 10 with FIG. 12). In this way, by freely arranging the optical axes of the blue laser light, the red laser light, and the fluorescent light three-dimensionally, the degree of freedom in arranging the light source increases, and the entire light source device can be made smaller.

[0068] <Fifth embodiment> A light source device 1 according to a fifth embodiment will be described with reference to Fig. 13. Fig. 13 is a diagram showing the configuration of a light source device 1 according to the fifth embodiment.

[0069] In the light source device 1 of the fifth embodiment, the set of the blue laser light source 10, the blue laser reduction element 30, and the first filter 50, and the set of the red laser light source 20, the red laser reduction element 40, and the second filter 60 are aligned in the Y-axis direction with their positions in the X-axis direction being the same. The order of the blue laser light source 10, the blue laser reduction element 30, and the first filter 50, and the order of the red laser light source 20, the red laser reduction element 40, and the second filter 60 are aligned from the + side to the - side in the X-axis direction. In other words, the set of the blue laser light source 10, the blue laser reduction element 30, and the first filter 50, and the set of the red laser light source 20, the red laser reduction element 40, and the second filter 60 are aligned completely in parallel. In the light source device 1 of the fifth embodiment, the cooling airflow used for one of the heat sinks, the heat sink 10B for the blue laser and the heat sink 20B for the red laser, can also be used to cool the other heat sink, thereby achieving high cooling efficiency and also making the device smaller and less expensive by reducing the number of fans.

[0070] Up to this point, the light source device 1 of the first to fifth embodiments has been described as an example. However, variations in which the first filter 50 and the second filter 60 are separately arranged on the optical path (gray scale) of the fluorescent light (third color light) between the wavelength conversion unit 80 and the light homogenizing element 100 are conceivable other than the light source device 1 of the first to fifth embodiments, and various design modifications can be made. In any case, by shifting the position of the laser light source, it is possible to prevent the light source device from becoming large in one direction and to arrange it with good cooling efficiency, so that the heat sink, etc. can be made smaller, and the device can be made smaller and lighter.

[0071] <Comparative Example> FIG. 14 is a diagram showing the configuration of a light source device of a comparative example.

[0072] In the light source device of the comparative example, a dichroic mirror is placed between the blue laser and the red laser, and the blue laser, dichroic mirror, and red laser are aligned in a straight line from top to bottom in Fig. 14 (the optical axes of the blue laser and the red laser located above and below the dichroic mirror are aligned). This makes the light source device itself larger in the vertical direction in Fig. 14. Furthermore, it is necessary to provide a heat sink for the blue laser and a heat sink for the red laser on the back of the blue laser and the red laser, which further increases the size of the light source device itself in the vertical direction in Fig. 14.

[0073] In addition, since it is necessary to reflect the blue laser and the red laser with a single dichroic mirror, the dichroic mirror must be made large. In addition, the reflection spectrum of the dichroic mirror is wide, and the width of the dichroic mirror is wide in the light beam width of the fluorescent light. Therefore, there is a concern that the fluorescent light from the phosphor will be blocked (vignetted) by the dichroic mirror, resulting in a decrease in the light utilization efficiency. Furthermore, due to the constraint of reflecting the blue laser and the red laser with a single dichroic mirror, it is difficult to change the characteristics, size, and arrangement of the filter, which also results in a decrease in the light utilization efficiency of the fluorescent light.

[0074] In the light source device of the comparative example, there are significant restrictions on the placement of the blue and red laser light sources, making it difficult to configure the light source device as a whole to fit snugly in place. In addition, restrictions on the placement of the light sources make it difficult to achieve a placement with good cooling efficiency, which results in the heat sink becoming larger and heavier.

[0075] In the light source device of the comparative example, one or two filters (coatings applied to a dichroic mirror) are provided on one side of the fluorescent light. Although blue-reflecting filters and red-reflecting filters transmit the fluorescent light, the transmittance of a dichroic mirror is generally about 96%, so the light utilization efficiency on one side of the optical path of the fluorescent light drops to a maximum of about 93%, which can result in color unevenness in the optical path of the fluorescent light.

[0076] <Projector (image projection device)> Fig. 15 is a diagram showing the configuration of a projector (image projection device) 200 of this embodiment. The projector 200 in Fig. 15 has a composite light source device that combines two light source devices: a light source device 1R that combines a blue laser light source 10 and a red laser light source 20, and a light source device 1G that combines a blue laser light source 10 and a green laser light source 20G. In addition, the light source device 1R and the light source device 1G share the light uniformizing element 100.

[0077] In the light source device 1R, the blue laser light emitted by the blue laser light source 10 is reflected by the first filter 50, and separated into blue laser light and fluorescent light by the wavelength conversion unit 80. Also, the red laser light emitted by the red laser light source 20 is reflected by the second filter 60. In Fig. 15, the light flux of the blue laser light is depicted by a dashed line, the light flux of the red laser light is depicted by a dashed line, and the light flux of the fluorescent light is depicted by a grayscale fill.

[0078] In light source device 1G, the blue laser light emitted by blue laser light source 10 is reflected by first filter 50 and separated into blue laser light and fluorescent light by wavelength conversion unit 80. Also, the green laser light emitted by green laser light source (second light source) 20G is reflected by second filter (second optical element, second dichroic mirror, second notch filter) 60G. In Fig. 15, the light flux of the blue laser light is drawn by a dashed line, the light flux of the green laser light is drawn by a two-dot chain line, and the light flux of the fluorescent light is drawn by a grayscale fill.

[0079] The blue laser light, red laser light and fluorescent light from light source device 1R, and the blue laser light, green laser light and fluorescent light from light source device 1G are combined by a light path combining element 210 having two mirrors and are guided to the light uniformizing element 100.

[0080] The projector 200 includes an illumination optical system 220, an image display element 230, a cooling device (heat sink) 240, and a projection optical system 250.

[0081] The illumination optical system 220 guides the light emitted from the light source devices 1R and 1G, which is incident via the light homogenizing element 100, to the image display element 230. The image display element 230 generates (outputs) an image using the light guided by the illumination optical system 220 (by modulating the illumination light). The cooling device 240 cools the image display element 230. The projection optical system 250 projects an image generated by the image display element 230 using the light guided by the illumination optical system 220 (by enlarging the light emitted from the image display element 230 and projecting it onto a screen).

[0082] According to the projector of this embodiment, since the red laser light and the green laser light are combined while suppressing the decrease in the light utilization efficiency of the fluorescent light, it is possible to achieve both brightness and color reproducibility. In addition, since the size of the projector is determined by the arrangement of the optical system and the cooling device other than the light source device, the arrangement of the light source can be arbitrarily determined, and this, combined with the advantage that the arrangement of the light source can be arbitrarily determined, allows the projector to be made compact.

[0083] As described above, in this embodiment, for a light source device used in an image projection device such as a projector, a reflection filter that guides multiple light beams emitted from multiple laser light sources is arranged for each laser light source, thereby increasing the degree of freedom in arranging the laser light sources, and since a reflection filter that reflects only the wavelength band of each laser can be selected as the reflection filter, even when the wavelength bands of the laser and fluorescence overlap, the loss of fluorescence can be reduced. In particular, by providing a reflection filter for each light source, the degree of freedom in layout is improved, making thermal design (heat dissipation design of the light source) easier and allowing for miniaturization of the device.

[0084] In this embodiment, the dichroic mirrors (first filter 50 and second filter 60) are as small as possible with respect to the optical path of the fluorescent light, and are arranged to avoid the optical axis 80A of the fluorescent light. The reflection spectrum of the dichroic mirror (second filter 60) corresponding to the red laser is narrowed. Furthermore, the dichroic mirror (second filter 60) corresponding to the red laser is arranged separately from the mirror (first filter 50) corresponding to the blue laser.

[0085] The light source device and image projection device of this embodiment can be applied, for example, to a light source module mounted in a high-output projector using a laser light source, but can also be applied to other lighting light sources that require high output.

[0086] In addition, although each of the above-mentioned embodiments shows a preferred embodiment of the present invention, the present invention is not limited to the contents thereof. In particular, the specific shapes and numerical values ​​of each part exemplified in each embodiment are merely examples of the embodiment of the present invention, and the technical scope of the present invention should not be interpreted in a limited manner based on these. Thus, the present invention is not limited to the contents described in the present embodiment, and can be appropriately modified within the scope of the gist of the present invention. [Explanation of symbols]

[0087] 1 1R 1G Light source device 10 Blue laser light source (first light source) 20 Red laser light source (second light source) 20G green laser light source (second light source) 30 Blue laser reduction element 40 Red laser reduction element 50 First filter (first optical element, first dichroic mirror, first notch filter) 60 Second filter (second optical element, second dichroic mirror, second notch filter) 60G 2nd Filter (2nd Optical Element, 2nd Dichroic Mirror, 2nd Notch Filter) 61 Reflection Contribution Department 62 Reflection non-contributing portion (filter formed portion, filter non-formed portion) 63 Glass substrate (non-reflective portion, filter-formed portion, non-filter-formed portion) 70 First focusing lens (first focusing element, focusing optical system) 80 Wavelength conversion unit (phosphor unit) 81 Drive mechanism 82 Rotation axis 83 Reflection area 84 Fluorescent Area 90 Second focusing lens (second focusing element, focusing optical system) 100 Light uniformizing element (light entrance element) 200 Projector (image projection device) 210 Optical path synthesis element 220 Illumination optical system 230 Image display element 240 Cooling device (heat sink) 250 Projection optical system

Claims

1. a first light source that emits a first color light; a second light source that emits a second color light; a wavelength conversion unit that converts at least a part of the first color light into a third color light and outputs the third color light; a light incident element onto which the first, second, and third color lights are incident; a first filter that reflects the first color light to the wavelength converting unit; a second filter that reflects the second color light to the light entrance element; having the first and second filters are separately disposed on an optical path of the third color light between the wavelength converting unit and the light incident element; a central axis of the first color light emitted from the first light source and a central axis of the second color light emitted from the second light source extend in a twisted relationship with each other on an optical path of the third color light between the wavelength conversion unit and the light incident element; A light source device characterized by:

2. a first light source that emits a first color light; a second light source that emits a second color light; a wavelength conversion unit that converts at least a part of the first color light into a third color light and outputs the third color light; a light incident element onto which the first, second, and third color lights are incident; a first filter that reflects the first color light to the wavelength converting unit; a second filter that reflects the second color light to the light entrance element; having the first and second filters are separately disposed on an optical path of the third color light between the wavelength converting unit and the light incident element; The first, second and third color lights are not located in the same plane. A light source device characterized by:

3. the second filter transmits a wavelength range of the third color light excluding the wavelength range of the second color light; 3. The light source device according to claim 1 or 2.

4. The wavelength conversion unit further includes a focusing optical system located between the wavelength conversion unit and the light entrance element, The second filter is disposed off the optical axis of the focusing optical system.

4. The light source device according to claim 1, wherein the light source device is a light source unit.

5. a central axis of the first color light emitted from the first light source and a central axis of the second color light emitted from the second light source are different from each other; 5. The light source device according to claim 1, wherein the light source device is a light source unit.

6. a second light collecting element located between the second filter and the light entrance element; When a projected area of ​​the third color light on the second light-collecting element is PSA3 and a projected area of ​​the second color light on the second light-collecting element is PSA2, conditional formula (1) is satisfied.

6. The light source device according to claim 1, wherein the light source device is a light source unit. (1) 0.100≦PSA2 / PSA3≦0.375

7. the second filter has a reflection contributing portion that contributes to the reflection of the second color light and a reflection non-contributing portion that does not contribute to the reflection of the second color light, 7. The light source device according to claim 1, wherein the light source device is a light source unit.

8. an amount of the second color light reflected by the second filter is greater than an amount of the third color light reflected by the second filter; 8. The light source device according to claim 1, wherein the light source device is a light source unit.

9. the first and second filters are provided such that there is no component of the third color light transmitted through both the first and second filters; 9. The light source device according to claim 1, wherein the light source device is a light source unit.

10. the first color light is blue light; the second color light is red light or green light, The third color light is a yellow or green fluorescent light.

10. The light source device according to claim 1, wherein the light source device is a light source unit.

11. the wavelength converting unit has a reflective area that reflects the first color light, a first focusing element located between the first filter and the wavelength converting unit, for focusing the first color light reflected by the first filter and for substantially parallelizing the first and third color lights emitted by the wavelength converting unit; The first color light is incident on the wavelength conversion unit through a portion of the first light-collecting element, reflected by the reflection area, and then emitted through another portion of the first light-collecting element.

11. The light source device according to claim 1,

12. A light source device according to any one of claims 1 to 11, an illumination optical system that guides light emitted from the light source device to an image display element; a projection optical system that projects an image generated by the image display element using the light guided by the illumination optical system.

Images