Illumination device and projector

Abstract

To provide an illumination device that can prevent a reduction in the light efficiency of a light source even when the area of a light emission surface is increased.SOLUTION: An illumination device comprises: a light source device having a light emission surface that emits first light; a first light guide element including a first reflection surface that reflects the first light emitted from the light emission surface on its inner surface, and a first emission end from which the first light reflected on the first reflection surface is emitted; and a second light guide element including a second incident end on which the first light emitted from the first emission end is incident, a second emission end from which the first light incident from the second incident end is emitted, and a second reflection surface that reflects the first light incident from the second incident end on its inner surface. The first reflection surface is inclined toward an optical axis along a direction in which the first light travels. When the area of the light emission surface is defined as S1, the area of a first emission surface of the first emission end as S2, the area of a second incident surface of the second incident end as S3, and the area of a second emission surface of the second emission end as S4, the following conditional expression is satisfied. S4>S1>S3≥S2.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a lighting device and a projector. [Background technology]

[0002] An illumination device used in a projector is described in Patent Document 1. The illumination device in this document includes a light emitter that emits diffused light and a light guide element that reflects the diffused light from the light emitter on its internal surface. The light guide element includes an incident end where the diffused light is incident, a reflective surface that reflects the diffused light incident from the incident end, and an exit end that emits the diffused light reflected by the reflective surface. The reflective surface is inclined radially outward from the center of the light guide element in the direction in which the emitted light travels. The incident end is larger than the exit surface of the light emitter. The exit end is larger than the incident end. The light guide element efficiently captures the diffused light from the light emitter and efficiently narrows the radiation angle to emit bright illumination light with high directionality. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-94115 Summary of the Invention [Problem to be solved by the invention]

[0004] To further increase the brightness of the illumination light emitted from the light-guiding element, it is possible to use a light-emitting element with a larger emission surface. However, if the emission surface of the light-emitting element is enlarged, the incident end of the light-guiding element must also be enlarged, which reduces the slope of the reflecting surface and reduces the directivity of the illumination light emitted from the emission end. Therefore, even if the emission surface of the light-emitting element is enlarged, the light efficiency of the light-emitting element decreases (the etendue increases). [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the lighting device of the present invention includes a light source device having a light-emitting surface that emits first light, a first reflecting surface that internally reflects the first light emitted from the light-emitting surface, and a first light-guiding element including a first emitting end portion from which the first light reflected by the first reflecting surface is emitted, and a second incident end portion into which the first light emitted from the first emitting end portion is incident, a second emitting end portion from which the first light incident from the second incident end is emitted, and a first light-guiding element including a second incident end portion that internally reflects the first light incident from the second incident end. and a second light-guiding element having a second reflecting surface, wherein the light source device, the first light-guiding element, and the second light-guiding element are arranged in this order along the optical axis of the first light-guiding element, and the first reflecting surface is inclined toward the optical axis according to the direction in which the first light travels, and the light source device is characterized in that, when an area of the light-emitting surface is S1, an area of a first exit surface of the first exit end is S2, an area of a second entrance surface of the second entrance end is S3, and an area of the second exit surface of the second exit end is S4, the light source device satisfies the following conditional formula: S4>S1>S3≧S2

[0006] The projector of the present invention is characterized by comprising the above-mentioned lighting device, a light modulation element that modulates the first light emitted from the lighting device to form a projection image, and a projection lens that projects the projection image as an enlarged image. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic diagram of a main part of a projector according to a first embodiment. [Figure 2] FIG. 2 is a perspective view of a first light guide element. [Figure 3] FIG. 2 is a perspective view of a second light guide element. [Figure 4] FIG. 10 is a schematic diagram of a main part of a projector according to a second embodiment. [Figure 5] FIG. 10 is a schematic diagram of a main part of a projector according to a third embodiment. [Figure 6] FIG. 10 is a schematic diagram of a main part of a projector according to a fourth embodiment. [Figure 7] FIG. 10 is a schematic diagram of a main part of a projector according to a fifth embodiment. [Figure 8] FIG. 13 is a schematic diagram of a main part of a projector according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Embodiment 1] 1 is a schematic diagram of the main parts of a projector according to embodiment 1. As shown in Fig. 1, the projector 1 includes an illumination device 2, an image forming unit 3 that generates a projection image to be projected onto a screen S, a projection lens 4 that enlarges the projection image and projects it onto the screen S, and a control unit 5 that controls the operation of the image forming unit 3.

[0009] The lighting device 2 includes a light source device 10, a first light guide element 21, and a second light guide element 25. The light source device 10, the first light guide element 21, and the second light guide element 25 are arranged in this order along the optical axis N of the first light guide element 21.

[0010] The light source device 10 has a light-emitting surface 100 that emits a first light L. The light source device 10 includes a light source 111, a fluorescent layer 112 that converts the light emitted by the light source 111 into the first light L, and a substrate 113 on which the light sources 111 are arranged. The light-emitting surface 100 is an exit surface 114 of the fluorescent layer 112. The area of the light-emitting surface 100 is 0.3 mm 2 ~20mm 2 is.

[0011] The light source 111 is an LED element. The LED element emits, for example, blue light. The fluorescent layer 112 covers the light source 111 on the substrate 113. The fluorescent layer 112 converts, for example, the blue light emitted by the light source 111 into a first light L that is white light. In this case, the fluorescent layer 112 is made of a phosphor that emits red light and a phosphor that emits green light. Note that the color of the light emitted by the light source 111 is not limited to blue light. Furthermore, the first light L converted by the fluorescent layer 112 is not limited to white light.

[0012] The first light guide element 21 reflects the first light L incident from the light source device 10 on its inner surface and emits the first light L. The second light guide element 25 reflects the first light L incident from the first light guide element 21 on its inner surface and emits the first light L. Here, the lighting device 2 includes a reflective first polarizing plate 35 arranged between the first light guide element 21 and the second light guide element 25, and a first Fresnel lens 36 arranged on the emission side of the second light guide element 25. The first Fresnel lens 36 collimates the first light L emitted from the second light guide element 25.

[0013] The first polarizing plate 35 reflects either the P-polarized component or the S-polarized component of the polarization components contained in the first light L output from the first light guide element 21, and transmits the other. In this embodiment, the first polarizing plate 35 reflects the S-polarized component of the polarization components contained in the first light L output from the first light guide element 21, and transmits the P-polarized component. The reflected S-polarized component of the first light L passes through the fluorescent layer 112, is reflected by the surface of the substrate 113, and is output again from the fluorescent layer 112. Note that, after output from the fluorescent layer 112, the S-polarized component of the first light L becomes unpolarized light including a P-polarized component. The S-polarized component of the unpolarized first light L is reflected by the first polarizing plate 35, and the P-polarized component passes through.

[0014] The image forming unit 3 includes a light modulation element 31, a second polarizing plate 32, and a second Fresnel lens 33. The light modulation element 31 modulates the first light L from the first Fresnel lens 36 into modulated light to form a projected image. The light modulation element 31 is a liquid crystal panel 310. The size of the effective display area of the liquid crystal panel 310 is 0.3 inches to 7.0 inches. In this embodiment, the liquid crystal panel 310 is made up of a single panel and includes pixels corresponding to the respective colors of light. As a result, the liquid crystal panel 310 modulates the first light L, which is white light, in accordance with the color light corresponding to each pixel, to form full-color image light.

[0015] The second polarizing plate 32 is disposed on the output side of the light modulation element 31, and transmits either the P-polarized component or the S-polarized component of the polarized components contained in the modulated light output from the light modulation element 31. In this embodiment, the second polarizing plate 32 transmits the S-polarized component of the polarized components contained in the modulated light output from the light modulation element 31. The second Fresnel lens 33 focuses the modulated light output from the second polarizing plate 32 onto the projection lens 4.

[0016] The projection lens 4 includes a plurality of lenses. The control unit 5 operates the liquid crystal panel 310 based on an external image signal such as a video signal.

[0017] (First light guide element) FIG. 2 is a perspective view of the first light guide element 21. The first light guide element 21 is made of metal. The first light guide element 21 is formed by processing a plate member such as stainless steel, aluminum, or copper. As shown in FIGS. 1 and 2, the first light guide element 21 includes a first incident end 22 into which the first light L is incident, a first reflecting surface 24 that reflects the first light L on its inner surface, and a first exit end 23 from which the first light L reflected by the first reflecting surface 24 is emitted. The first light guide element 21 has a hollow structure and is a cylindrical reflector with openings provided at the first incident end 22 and the first exit end 23.

[0018] A first incident surface 220 is formed at the first incident end 22. A first exit surface 230 is formed at the first exit end 23. The first incident surface 220 and the first exit surface 230 are circular. When viewed from the direction along the optical axis N, the first incident surface 220 overlaps with the light emitting surface 100 of the light source device 10, and the dimensions of the first incident surface 220 are larger than or approximately the same as the dimensions of the light emitting surface 100. The area of the first exit surface 230 is 0.15 mm 2 ~10mm 2 is.

[0019] The first reflecting surface 24 is inclined toward the optical axis N from the first incident end 22 to the first exit end 23. That is, the first reflecting surface 24 is inclined toward the optical axis N in accordance with the traveling direction of the first light L. Therefore, the luminous flux width of the first light L becomes smaller in accordance with the traveling direction of the first light L, and the first light L is condensed.

[0020] The first reflecting surface 24 is an inner surface of the first light guide element 21. The first reflecting surface 24 is a curved surface 240 that curves radially outward with respect to the optical axis N of the first light guide element 21. The curved surface 240 has a shape that is rotationally symmetric with the optical axis N as the center of rotation. The first reflecting surface 24 may be mirror-finished. The first reflecting surface 24 may also be coated with a reflective film.

[0021] (Second light guide element) FIG. 3 is a perspective view of the second light guide element 25. The second light guide element 25 is made of metal. The second light guide element 25 is formed by processing a plate member such as stainless steel, aluminum, or copper. As shown in FIGS. 1 and 3 , the second light guide element 25 includes a second incident end 26 into which the first light L emitted from the first incident end 23 enters, a second exit end 27 from which the first light L incident from the second incident end 26 exits, and a second reflecting surface 28 that internally reflects the first light L incident from the second incident end 26. The second light guide element 25 has a hollow structure and is a cylindrical reflector with openings provided at the second incident end 26 and the second exit end 27. The optical axis M of the second light guide element 25 coincides with the optical axis N of the first light guide element 21.

[0022] A second incident surface 260 is formed at the second incident end 26. A second exit surface 270 is formed at the second exit end 27. The second incident surface 260 and the second exit surface 270 are rectangular. The area of the second incident surface 260 is 0.15 mm 2 ~10mm 2 The area of the second exit surface 270 is 57.1424 mm 2 ~14630.04mm 2 is.

[0023] The second reflecting surface 28 is the inner surface of the second light guide element 25. The second reflecting surface 28 is a flat surface that inclines radially outward with respect to the optical axis M from the second incident end 26 toward the second exit end 27. Therefore, the luminous flux width of the first light L increases along the direction in which the first light L travels. The second reflecting surface 28 may be mirror-finished. The second reflecting surface 28 may also be coated with a reflective film.

[0024] Here, if the area of the light-emitting surface 100 is S1, the area of the first exit surface 230 of the first exit end 23 is S2, the area of the second incident surface 260 of the second incident end 26 is S3, and the area of the second exit surface 270 of the second exit end 27 is S4, the following conditional formula is satisfied. S4>S1>S3≧S2

[0025] (Action and effect) The projector 1 of this embodiment includes a light source device 10 having a light-emitting surface 100 that emits a first light L, a first light guide element 21 that includes a first reflecting surface 24 that internally reflects the first light emitted from the light-emitting surface 100 and a first exit end 23 from which the first light L reflected by the first reflecting surface 24 is emitted, and a second light guide element 25 that includes a second incident end 26 into which the first light L emitted from the first exit end 23 is incident, a second exit end 27 from which the first light L incident from the second incident end 26 is emitted, and a second reflecting surface 28 that internally reflects the first light L incident from the second incident end 26. The light source device 10, the first light guide element 21, and the second light guide element 25 are arranged in this order along an optical axis N of the first light guide element 21. The first reflecting surface 24 is inclined toward the optical axis N in accordance with the direction in which the first light L travels. If the area of the light-emitting surface 100 is S1, the area of the first exit surface 230 of the first exit end 23 is S2, the area of the second incident surface 260 of the second incident end 26 is S3, and the area of the second exit surface 270 of the second exit end 27 is S4, the following conditional formula is satisfied. S4>S1>S3≧S2

[0026] According to this embodiment, the first light guide element 21 can emit the first light L, the luminous flux width of which has been reduced by the first reflecting surface 24, from the first exit surface 230. Therefore, even when the area of the light-emitting surface 100 is larger than the area of the second incident surface 260, the second light guide element 25 can take in the first light L from the first light guide element 21 without increasing the area of the second incident surface 260. As a result, even when the area of the light-emitting surface 100 is increased, a decrease in the optical efficiency of the light source device 10 (an increase in Etendue) can be suppressed. Furthermore, since the area of the second incident surface 260 is equal to or larger than the area of the first exit surface 230, the second light guide element 25 can effectively take in the first light L when taking in the first light L from the first light guide element 21. Furthermore, since the area of the second exit surface 270 is larger than the area of the light-emitting surface 100, an increase in the size of the lighting device 2 is suppressed.

[0027] The first reflecting surface 24 includes a curved surface 240 that curves radially outward with respect to the optical axis N of the first light guide element 21. With this, the curved surface 240 of the first light guide element 21 can make the first light L emitted from the first emission surface 230 uniform, and can reduce the radiation angle of the first light L emitted from the first light guide element 21, thereby suppressing a decrease in the optical efficiency of the light source device 10.

[0028] The light source device 10 includes a light source 111 that emits light, and a fluorescent layer 112 that converts the light emitted by the light source 111 into first light L. The light-emitting surface 100 is the emission surface of the fluorescent layer 112. This allows the fluorescent layer 112 to convert the wavelength of the first light L.

[0029] The lighting device 2 includes a reflective first polarizing plate 35 disposed between the first exit end 23 and the second entrance end 26. This allows the size of the first polarizing plate 35 to be smaller than when the first polarizing plate 35 is disposed on the exit side of the second light guide element 25. Furthermore, because the first polarizing plate 35 is reflective, among the polarized components contained in the first light L, light of the polarized component reflected by the first polarizing plate 35 passes through the fluorescent layer 112, is reflected by the surface of the substrate 113 of the light source 111, and is again emitted from the fluorescent layer 112 to reach the first polarizing plate 35. Here, the first light L that has again reached the first polarizing plate 35 becomes unpolarized on the way to the first polarizing plate 35. This allows the utilization efficiency of the first light L to be improved even when the first polarizing plate 35 is disposed between the first exit end 23 and the second entrance end 26.

[0030] The second light exit surface 270 has a rectangular shape. This allows the luminous flux of the first light L exiting from the second light exit surface 270 to have a rectangular shape, so that when the illumination device 2 illuminates the liquid crystal panel 310 used in the projector 1, the liquid crystal panel 310 can be illuminated efficiently.

[0031] The first light guide element 21 and the second light guide element 25 are made of metal. This allows the interior to be a reflective surface. Furthermore, the first light guide element 21 and the second light guide element 25 are easy to manufacture. Furthermore, the component strength of the first light guide element 21 and the second light guide element 25 can be increased.

[0032] The first light guide element 21 has a hollow structure, which can reduce the weight of the first light guide element 21. In addition, since the inside of the first light guide element 21 is hollow, the heat dissipation effect of the first light guide element 21 can be improved by flowing air inside the first light guide element 21.

[0033] The second light guide element 25 has a hollow structure, which can reduce the weight of the second light guide element 25. In addition, since the inside of the second light guide element 25 is hollow, the heat dissipation effect of the second light guide element 25 can be improved by flowing air inside the second light guide element 25.

[0034] The lighting device 2 includes a first Fresnel lens 36 that collimates the first light L emitted from the second light guide element 25. This allows a luminous flux larger than that of the light emitting surface 100 to be converted into parallel light.

[0035] The projector 1 of this embodiment includes an illumination device 2, a light modulation element 31 that modulates the first light L emitted from the illumination device 2 to form a projection image, and a projection lens 4 that projects the projection image as an enlarged image. As a result, the first light L emitted from the illumination device 2 is prevented from becoming large in size, which reduces light loss in the light modulation element 31 and the projection lens 4. As a result, a bright projector 1 can be realized.

[0036] The area of the light-emitting surface 100 is 0.3 mm 2 ~20mm 2 The area of the first light exit surface 230 is 0.15 mm 2 ~10mm 2 The area of the second incident surface 260 is 0.15 mm 2 ~10mm 2 The area of the second exit surface 270 is 57.1424 mm 2 ~14630.04mm 2 This makes it possible to prevent the projector 1 from becoming large while ensuring the brightness of the projector 1.

[0037] The size of the effective display area of the light modulation element 31 is 0.3 to 7.0 inches. This makes it possible to prevent the light modulation element 31 from becoming too large, while also preventing the light efficiency of the light source device 10 from decreasing.

[0038] [Embodiment 2] 4 is a schematic diagram of the main parts of a projector 1A of embodiment 2. The projector 1A of embodiment 2 differs from the projector 1 of embodiment 1 in a first light guide element 21A and a second light guide element 25A. Therefore, in embodiment 2, the same components as those in embodiment 1 are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0039] 4, the lighting device 2 includes a light source device 10, a first light guide element 21A, and a second light guide element 25A. The light source device 10, the first light guide element 21A, and the second light guide element 25A are arranged in this order along the optical axis N of the first light guide element 21.

[0040] The lighting device 2 includes a reflective first polarizing plate 35 disposed between the first light guide element 21A and the second light guide element 25A, and a first Fresnel lens 36 disposed on the exit side of the second light guide element 25A.

[0041] The first light guide element 21A is made of resin or glass. As shown in Fig. 4, the first light guide element 21A includes a first incident end 22 into which the first light L is incident, a first reflecting surface 24 that internally reflects the first light L, and a first exit end 23 from which the first light L reflected by the first reflecting surface 24 is emitted. The first light guide element 21A has a solid structure and is an internal reflection type optical rod.

[0042] A first incident surface 220 is formed at the first incident end 22. A first exit surface 230 is formed at the first exit end 23. The first incident surface 220 and the first exit surface 230 are circular. When viewed from the direction along the optical axis N, the first incident surface 220 overlaps with the light emitting surface 100 of the light source device 10, and the dimensions of the first incident surface 220 are larger than or approximately the same as the dimensions of the light emitting surface 100. The area of the first exit surface 230 is 0.15 mm 2 ~10mm 2 is.

[0043] The first reflecting surface 24 is formed by providing a reflective coating layer on the outer surface of the first light guide element 21A. The first reflecting surface 24 is inclined toward the optical axis N from the first incident end 22 to the first exit end 23. That is, the first reflecting surface 24 is inclined toward the optical axis N in accordance with the traveling direction of the first light L. Therefore, the luminous flux width of the first light L becomes smaller in accordance with the traveling direction of the first light L, and the first light L is condensed. The first reflecting surface 24 is a curved surface 240 that curves radially outward with respect to the optical axis N of the first light guide element 21. The curved surface 240 has a shape that is rotationally symmetrical with the optical axis N as the center of rotation.

[0044] The second light guide element 25A is made of resin or glass. As shown in Fig. 4, the second light guide element 25A includes a second incident end 26 into which the first light L emitted from the first incident end 23 enters, a second incident end 27 from which the first light L incident from the second incident end 26 exits, and a second reflecting surface 28 that internally reflects the first light L incident from the second incident end 26. The second light guide element 25 has a solid structure and is an internal reflection type optical rod. The optical axis M of the second light guide element 25 coincides with the optical axis N of the first light guide element 21.

[0045] A second incident surface 260 is formed at the second incident end 26. A second exit surface 270 is formed at the second exit end 27. The second incident surface 260 and the second exit surface 270 are rectangular. The area of the second incident surface 260 is 0.15 mm 2 ~10mm 2 The area of the second exit surface 270 is 57.1424 mm 2 ~14630.04mm 2 is.

[0046] The second reflecting surface 28 is formed by providing a reflective coating layer on the outer surface of the second light guide element 25A. In this embodiment, the second reflecting surface 28 is a flat surface that is inclined radially outward with respect to the optical axis M from the second incident end portion 26 toward the second output end portion 27. Therefore, the luminous flux width of the first light L increases along the traveling direction of the first light L.

[0047] Here, if the area of the light-emitting surface 100 is S1, the area of the first exit surface 230 of the first exit end 23 is S2, the area of the second incident surface 260 of the second incident end 26 is S3, and the area of the second exit surface 270 of the second exit end 27 is S4, the following conditional formula is satisfied. S4>S1>S3≧S2

[0048] (Action and effect) The first light guide element 21A has a solid structure. The second light guide element 25A has a solid structure. This can increase the component strength of the first light guide element 21A and the second light guide element 25A. The second embodiment has the same configuration as the first embodiment and can achieve the same effects as the first embodiment.

[0049] [Embodiment 3] 5 is a schematic diagram of the main parts of a projector 1B of embodiment 3. The projector 1B of embodiment 3 differs from the projector 1 of embodiment 1 in a first light guide element 21B and a second light guide element 25B. Therefore, in embodiment 3, the same components as those in embodiment 1 are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0050] 5, the lighting device 2 includes a light source device 10, a first light guide element 21B, and a second light guide element 25B. The light source device 10, the first light guide element 21B, and the second light guide element 25B are arranged in this order along the optical axis N of the first light guide element 21. In this embodiment, the first light guide element 21B and the second light guide element 25B are integrally formed.

[0051] The lighting device 2 includes a reflective first polarizing plate 35 arranged on the light-emitting side of the second light guide element 25, and a first Fresnel lens 36 arranged on the light-emitting side of the first polarizing plate 35.

[0052] The first polarizing plate 35 reflects one of the P-polarized component and the S-polarized component among the polarization components contained in the first light L output from the second light guide element 25, and transmits the other. In this embodiment, the first polarizing plate 35 reflects the S-polarized component among the polarization components contained in the first light L output from the second light guide element 25, and transmits the P-polarized component.

[0053] The first light guide element 21B and the second light guide element 25B are made of metal. The first light guide element 21B and the second light guide element 25B are formed by processing a plate member such as stainless steel, aluminum, or copper. As shown in FIG. 5 , the first light guide element 21B includes a first incident end 22 into which the first light L is incident, a first reflecting surface 24 that internally reflects the first light L, and a first exit end 23 from which the first light L reflected by the first reflecting surface 24 is emitted. The first light guide element 21B has a hollow structure and is a cylindrical reflector with openings provided at the first incident end 22 and the first exit end 23.

[0054] A first incident surface 220 is formed at the first incident end 22. A first exit surface 230 is formed at the first exit end 23. The first incident surface 220 has a circular shape. When viewed from the direction along the optical axis N, the first incident surface 220 overlaps with the light emitting surface 100 of the light source device 10, and the dimensions of the first incident surface 220 are larger than or approximately the same as the dimensions of the light emitting surface 100. The area of the first exit surface 230 is 0.15 mm 2 ~10mm 2 is.

[0055] The first reflecting surface 24 is inclined toward the optical axis N from the first incident end 22 to the first exit end 23. That is, the first reflecting surface 24 is inclined toward the optical axis N in accordance with the traveling direction of the first light L. Therefore, the luminous flux width of the first light L becomes smaller in accordance with the traveling direction of the first light L, and the first light L is condensed. The first reflecting surface 24 is a curved surface 240 that curves radially outward with respect to the optical axis N of the first light guide element 21. The curved surface 240 has a shape that is rotationally symmetrical with the optical axis N as the center of rotation.

[0056] 5, second light guide element 25B includes second incident end 26 into which first light L emitted from first output end 23 enters, second output end 27 from which first light L incident from second incident end 26 exits, and second reflecting surface 28 that internally reflects first light L incident from second incident end 26. Second light guide element 25 has a hollow structure and is a cylindrical reflector having openings at second incident end 26 and second output end 27. Optical axis M of second light guide element 25 coincides with optical axis N of first light guide element 21.

[0057] A second incident surface 260 is formed at the second incident end 26. A second exit surface 270 is formed at the second exit end 27. The second exit surface 270 is rectangular. The second incident surface 260 has the same shape as the first exit surface 230. The first exit surface 230 and the second incident surface 260 may be circular, rectangular, elliptical, polygonal, or the like. The area of the second incident surface 260 is 0.15 mm 2 ~10mm 2 The area of the second exit surface 270 is 57.1424 mm 2 ~14630.04mm 2 is.

[0058] The second reflecting surface 28 is a flat surface that inclines radially outward with respect to the optical axis M from the second incident end 26 toward the second exit end 27. Therefore, the luminous flux width of the first light L increases along the direction in which the first light L travels. The second reflecting surface 28 is formed by mirror-finishing the inside of the second light guide element 25. Alternatively, the second reflecting surface 28 may be formed by coating the inside of the second light guide element 25 with a reflective film.

[0059] Here, if the area of the light-emitting surface 100 is S1, the area of the first exit surface 230 of the first exit end 23 is S2, the area of the second incident surface 260 of the second incident end 26 is S3, and the area of the second exit surface 270 of the second exit end 27 is S4, the following conditional formula is satisfied. S4>S1>S3≧S2

[0060] (Action and effect) In this embodiment, the first light guide element 21B and the second light guide element 25B are integrally formed. This allows the first light guide element 21B and the second light guide element 25B to be formed as a single component, thereby reducing component costs. Furthermore, the second light guide element 25B can take in all of the first light L from the first light guide element 21A. This reduces light loss and makes the first light L emitted from the second light guide element 25B brighter than when the first light guide element 21A and the second light guide element 25B are formed separately. The third embodiment has the same configuration as the first embodiment and can achieve the same effects as the first embodiment.

[0061] [Embodiment 4] 6 is a schematic diagram of the main parts of a projector 1C of embodiment 4. The projector 1C of embodiment 4 differs from the projector 1 of embodiment 1 in a light source device 10C and a first light guide element 21C. Therefore, in embodiment 4, the same components as those of embodiment 1 are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0062] 6, the lighting device 2 includes a light source device 10C, a first light guide element 21C, and a second light guide element 25. The light source device 10C, the first light guide element 21C, and the second light guide element 25 are arranged in this order along the optical axis N of the first light guide element 21C.

[0063] The light source device 10C has a light-emitting surface 100 that emits a first light L. The light source device 10C includes a light source 111, a fluorescent layer 112 that converts the light emitted by the light source 111 into the first light L, and a substrate 113 on which the light sources 111 are arranged. The light source 111 is an LED element. The fluorescent layer 112 is disposed inside the first light guide element 21C. The light-emitting surface 100 is an exit surface 114 of the fluorescent layer 112. The area of the light-emitting surface 100 is 0.3 mm 2 ~20mm 2 is.

[0064] The first light guide element 21C has the same configuration as the first light guide element 21 of the first embodiment, except that a fluorescent layer 112 is disposed inside. In this embodiment, the entire internal space of the first light guide element 21C is filled with the fluorescent layer 112. The light-emitting surface 100 includes a portion in contact with the first reflecting surface 24. Note that only a portion of the internal space of the first light guide element 21C may be filled with the fluorescent layer 112.

[0065] Here, if the area of the light-emitting surface 100 is S1, the area of the first exit surface 230 of the first exit end 23 is S2, the area of the second incident surface 260 of the second incident end 26 is S3, and the area of the second exit surface 270 of the second exit end 27 is S4, the following conditional formula is satisfied. S4>S1>S3≧S2

[0066] (Action and effect) Even when the phosphor layer 112 is disposed in the internal space of the first light guide element 21C, the fourth embodiment can achieve the same effects as the first embodiment.

[0067] [Embodiment 5] 7 is a schematic diagram of the main parts of a projector 1D of embodiment 5. Projector 1D of embodiment 5 differs from projector 1 of embodiment 1 in that a light source device 10D is different. Therefore, in embodiment 5, the same components as those in embodiment 1 are given the same reference numerals, and descriptions thereof may be omitted.

[0068] 7, the lighting device 2 includes a light source device 10D, a first light guide element 21, and a second light guide element 25. The light source device 10D, the first light guide element 21, and the second light guide element 25 are arranged in this order along the optical axis N of the first light guide element 21.

[0069] The light source device 10D has a light-emitting surface 100 that emits a first light L. The light source device 10D includes a light source 111, a diffusion plate 115 that diffuses the light emitted by the light source 111, a fluorescent layer 116 that converts the light diffused by the diffusion plate 115 into the first light L, and a substrate 113 on which the light sources 111 are arranged. The light source 111 is a semiconductor laser. The semiconductor laser emits, for example, blue light. The fluorescent layer 116 is disposed on the emission side of the diffusion plate 115. The light-emitting surface 100 is an emission surface 117 of the fluorescent layer 116. The area of the light-emitting surface 100 is 0.3 mm 2 ~20mm 2 The fluorescent layer 116 converts, for example, the blue light diffused by the diffusion plate 115 into the first light L, which is white light. In this case, the fluorescent layer 116 is made of a phosphor that emits red light and a phosphor that emits green light. Note that the color of the light emitted by the light source 111 is not limited to blue light. Furthermore, the first light L converted by the fluorescent layer 116 is not limited to white light.

[0070] Here, if the area of the light-emitting surface 100 is S1, the area of the first exit surface 230 of the first exit end 23 is S2, the area of the second incident surface 260 of the second incident end 26 is S3, and the area of the second exit surface 270 of the second exit end 27 is S4, the following conditional formula is satisfied. S4>S1>S3≧S2

[0071] (Action and effect) In this embodiment, the light source device 10 includes a diffuser plate 115 between the light source 111 and the fluorescent layer 116, which diffuses the light emitted by the light source 111. The light source 111 is a semiconductor laser. This increases the intensity of the light from the light source 111, thereby improving the efficiency of conversion into the first light L in the fluorescent layer 116. Furthermore, the diffuser plate 115 increases the diffusion angle of the light incident on the fluorescent layer 116, thereby suppressing bleeding that occurs when the fluorescent layer 116 emits the first light L. With a configuration similar to that of the first embodiment, the fifth embodiment can achieve the same effects as the first embodiment.

[0072] [Embodiment 6] Fig. 8 is a schematic diagram of the main parts of a projector 1E according to a sixth embodiment. As shown in Fig. 8, the projector 1E causes light from three light sources to enter three light modulation elements via light guide elements, and combines and projects three image lights. The projector 1E includes three lighting devices 2, three image forming units 3, a light combining element 9, a projection lens 4, and a control unit that controls the operation of the image forming units 3.

[0073] The illumination device 2 includes a first illumination device 2A, a second illumination device 2B, and a third illumination device 2C. Each of the first illumination device 2A, the second illumination device 2B, and the third illumination device 2C includes a light source device 10, a first light guide element 21, and a second light guide element 25. The first light guide element 21 and the second light guide element 25 are similar to those in the projector 1 of the first embodiment.

[0074] The light source device 10G of the first illumination device 2A emits a first light. The light source device 10R of the second illumination device 2B emits a second light different from the first light. The light source device 10B of the third illumination device 2C emits a third light different from the first light and the second light. The first light is green light. The second light is red light. The third light is blue light. The basic configuration of each light source device 10 is the same as that of the light source device 10 of the first embodiment.

[0075] Each light source 111 is an LED element. Each fluorescent layer 112 converts the light emitted by the light source 111 according to the color of the light emitted by each light source device 10.

[0076] The image forming unit 3 includes a first image forming unit 3A, a second image forming unit 3B, and a third image forming unit 3C. The first image forming unit 3A, the second image forming unit 3B, and the third image forming unit 3C each include a light modulation element 31, a second polarizing plate 32, and a second Fresnel lens 33. The second polarizing plate 32 and the second Fresnel lens 33 are the same as those in the projector 1 of the first embodiment.

[0077] The light modulation element 31G of the first image forming unit 3A modulates green light into modulated light to form a projection image. The light modulation element 31R of the second image forming unit 3B modulates red light into modulated light to form a projection image. The light modulation element 31B of the third image forming unit 3C modulates blue light into modulated light to form a projection image. Each light modulation element 31 is a liquid crystal panel 310.

[0078] The three modulated lights are incident on the light combining element 9 from different directions. The projector 1E projects the full-color projection image output from the light combining element 9 onto the screen S as an enlarged image.

[0079] (Action and effect) Even in a projector using three liquid crystal panels 310 as in this embodiment, the sixth embodiment can achieve the same effects as the first embodiment.

[0080] [Variations] The projector according to the modification of the first embodiment may employ the first light guide element 21A of the second embodiment instead of the first light guide element 21 of the first embodiment. Also, the projector according to the modification of the first embodiment may employ the second light guide element 25A of the second embodiment instead of the second light guide element 25 of the first embodiment.

[0081] The projector according to the modification of the first embodiment may include a transparent cover member that closes the opening of the first emission end portion 23.

[0082] In the projector 1 of Embodiment 1, the first light guide element 21 is made of metal, but in a projector according to a modification of Embodiment 1, the first light guide element 21 may be made of resin or glass. In this case, the first reflecting surface 24 is formed by coating the inside of the first light guide element 21 with a reflective film.

[0083] In the projector 1 of the first embodiment, the second light guide element 25 is made of metal, but in a projector of a modified example of the first embodiment, the second light guide element 25 may be made of resin or glass. In this case, the second reflecting surface 28 is formed by coating the inside of the second light guide element 25 with a reflective film.

[0084] In the projector 1 of the first embodiment, the first polarizing plate 35 is disposed between the first light guide element 21 and the second light guide element 25, but in the projector of the modified example of the first embodiment, the first polarizing plate 35 may be disposed on the output side of the second light guide element 25. Similarly, in the projector of the modified example of the second embodiment, the first polarizing plate 35 may be disposed on the output side of the second light guide element 25A.

[0085] In the above embodiment, the first reflecting surface 24 is a curved surface 240 that curves radially outward relative to the optical axis N of the first light-guiding element 21, but the first reflecting surface 24 may also be a surface that extends linearly radially outward relative to the optical axis N.

[0086] In the above embodiment, first incident surface 220 and first exit surface 230 are circular, but first incident surface 220 and first exit surface 230 may be rectangular, elliptical, or polygonal.

[0087] In the above embodiment, second exit surface 270 is rectangular, but second entrance surface 260 and second exit surface 270 may be circular, elliptical, or polygonal.

[0088] Summary of this disclosure A summary of this disclosure is provided below.

[0089] (Appendix 1) a light source device having a light emitting surface that emits a first light; a first light guide element including a first reflecting surface that reflects the first light emitted from the light emitting surface on an inner surface thereof, and a first emitting end portion from which the first light reflected by the first reflecting surface is emitted; a second light guide element including a second incident end into which the first light emitted from the first emitting end is incident, a second emitting end from which the first light incident from the second incident end is emitted, and a second reflecting surface that internally reflects the first light incident from the second incident end; Equipped with the light source device, the first light guide element, and the second light guide element are arranged in this order along an optical axis of the first light guide element; the first reflecting surface is inclined toward the optical axis in accordance with the direction in which the first light travels, An illumination device characterized in that the area of the light-emitting surface is S1, the area of the first exit surface of the first exit end is S2, the area of the second entrance surface of the second entrance end is S3, and the area of the second exit surface of the second exit end is S4, satisfying the following conditional formula: S4>S1>S3≧S2

[0090] As a result, the first light guide element can emit the first light, the luminous flux width of which has been reduced by the first reflecting surface, from the first exit surface. Therefore, even if the area of the light-emitting surface is larger than the area of the second incident surface, the second light guide element can capture the first light from the first light guide element without increasing the area of the second incident surface. As a result, even if the area of the light-emitting surface is increased, a decrease in the light efficiency of the light source device (increase in Etendue) can be suppressed. Furthermore, because the area of the second incident surface is equal to or larger than the area of the first exit surface, the second light guide element can effectively capture the first light when capturing the first light from the first light guide element. Furthermore, because the area of the second exit surface is larger than the area of the light-emitting surface, an increase in the size of the lighting device is suppressed.

[0091] (Appendix 2) 2. The lighting device according to claim 1, wherein the first reflecting surface has a curved surface that curves radially outward with respect to the optical axis of the first light guide element.

[0092] As a result, the curved surface of the first light guide element can make the first light emitted from the first emission surface uniform, and can reduce the radiation angle of the first light emitted from the first light guide element, thereby preventing a decrease in the light efficiency of the light source device.

[0093] (Appendix 3) the light source device includes a light source that emits light and a fluorescent layer that converts the light emitted by the light source into the first light; 3. The lighting device according to claim 1, wherein the light-emitting surface is an exit surface of the fluorescent layer.

[0094] This allows the fluorescent layer to convert the wavelength of the first light.

[0095] (Appendix 4) the light source device includes a diffusion plate between the light source and the fluorescent layer that diffuses the light emitted from the light source, 4. The lighting device according to claim 3, wherein the light source is a semiconductor laser.

[0096] This increases the intensity of light from the light source, thereby improving the efficiency of conversion into the first light in the fluorescent layer. In addition, the diffusion plate increases the diffusion angle of light incident on the fluorescent layer, thereby suppressing bleeding that occurs when the fluorescent layer emits the first light.

[0097] (Appendix 5) 5. The lighting device according to claim 1, further comprising a reflective polarizing plate disposed between the first exit end and the second entrance end.

[0098] This allows the size of the polarizing plate to be smaller than when the polarizing plate is disposed on the output side of the second light guide element. Furthermore, since the polarizing plate is reflective, among the polarized components contained in the first light, the polarized component light reflected by the polarizing plate passes through the fluorescent layer, is reflected by the surface of the light source, and is again emitted from the fluorescent layer to reach the polarizing plate. Here, the first light that reaches the polarizing plate again becomes unpolarized on the way to the polarizing plate. This allows the utilization efficiency of the first light to be improved even when the polarizing plate is disposed between the first output end and the second input end.

[0099] (Appendix 6) 5. The lighting device according to claim 1, wherein the first light guide element and the second light guide element are integrally formed.

[0100] This allows the first light guide element and the second light guide element to be integrated into one component, thereby reducing component costs. Also, since the second light guide element can take in all of the first light from the first light guide element, light loss can be reduced compared to when the first light guide element and the second light guide element are configured separately, and the first light emitted from the second light guide element can be brighter.

[0101] (Appendix 7) 7. The lighting device according to claim 1, wherein the second light exit surface is rectangular.

[0102] This allows the luminous flux of the first light emitted from the second exit surface to be rectangular, so that when the lighting device illuminates, for example, a liquid crystal panel used in a projector, the liquid crystal panel can be illuminated efficiently.

[0103] (Appendix 8) 8. The lighting device according to claim 1, wherein the first light guide element and the second light guide element are made of metal.

[0104] This allows the interior to be a reflective surface, facilitating the manufacture of the first light guide element and the second light guide element, and increasing the component strength of the first light guide element and the second light guide element.

[0105] (Appendix 9) 9. The lighting device according to claim 1, wherein the first light guide element has a hollow structure.

[0106] This reduces the weight of the first light guide element. In addition, since the inside of the first light guide element is hollow, the heat dissipation effect of the first light guide element can be improved by flowing air inside the first light guide element.

[0107] (Appendix 10) 10. The lighting device according to claim 1, wherein the second light guide element has a hollow structure.

[0108] This reduces the weight of the second light guide element. In addition, since the second light guide element is hollow, the heat dissipation effect of the second light guide element can be improved by allowing air to flow inside the second light guide element.

[0109] (Appendix 11) 11. The lighting device according to claim 1, further comprising a collimator lens that collimates the first light emitted from the second light guide element.

[0110] This allows a luminous flux larger than the light emitting surface to be converted into parallel light.

[0111] (Appendix 12) An illumination device according to any one of Supplementary Notes 1 to 11; a light modulation element that modulates the first light emitted from the illumination device to form a projection image; a projection lens that projects the projected image as an enlarged image; A projector comprising:

[0112] This makes it possible to realize a bright projector by using an illumination device that prevents the Etendue from becoming too large.

[0113] (Appendix 13) The area of the light-emitting surface is 0.3 mm 2 ~20mm 2 and The area of the first exit surface is 0.15 mm 2 ~10mm 2 and The area of the second incident surface is 0.15 mm 2 ~10mm 2 and The area of the second exit surface is 57.1424 mm 2 ~14630.04mm 2 13. The projector according to claim 12,

[0114] This makes it possible to prevent the projector from becoming too large while ensuring the brightness of the projector.

[0115] (Appendix 14) 14. The projector according to claim 12 or 13, wherein the size of the effective display area of the light modulation element is 0.3 to 7.0 inches.

[0116] This makes it possible to prevent the optical modulation element from becoming larger, while also preventing the light efficiency of the light source device from decreasing. [Explanation of symbols]

[0117] REFERENCE SIGNS LIST 1, 1A, 1B, 1C, 1D, 1E...projector, 2...illumination device, 2A...first illumination device, 2B...second illumination device, 2C...third illumination device, 3...image forming section, 3A...first image forming section, 3B...second image forming section, 3C...third image forming section, 4...projection lens, 5...control section, 10, 10C, 10D, 10G, 10R, 10B...light source device, 21, 21A, 21B, 21C...first light guide element, 22...first incident end portion, 23...first exit end portion, 24...first reflecting surface, 25, 25A, 25B...second light guide element, 26...second incident end portion, 27...second exit end portion, 28 ...second reflecting surface, 31, 31G, 31R, 31B...light modulation element, 32...second polarizing plate, 33...second Fresnel lens, 35...first polarizing plate, 36...first Fresnel lens, 100...light emitting surface, 111...light source, 112...fluorescent layer, 113...substrate, 113...surface, 114...exit surface, 115...diffuser, 116...fluorescent layer, 117...exit surface, 220...first incident surface, 230...first exit surface, 240...curved surface, 260...second incident surface, 270...second exit surface, 310...liquid crystal panel, L...first light, N...optical axis of first light guide element, M...optical axis of second light guide element, S...screen.

Claims

1. a light source device having a light emitting surface that emits a first light; a first light guide element including a first reflecting surface that reflects the first light emitted from the light emitting surface on an inner surface thereof, and a first emitting end portion from which the first light reflected by the first reflecting surface is emitted; a second light guide element including a second incident end into which the first light emitted from the first emitting end is incident, a second emitting end from which the first light incident from the second incident end is emitted, and a second reflecting surface that internally reflects the first light incident from the second incident end; Equipped with the light source device, the first light guide element, and the second light guide element are arranged in this order along an optical axis of the first light guide element; the first reflecting surface is inclined toward the optical axis in accordance with the traveling direction of the first light, an illumination device characterized in that, when an area of the light-emitting surface is S1, an area of a first exit surface of the first exit end is S2, an area of a second incident surface of the second incident end is S3, and an area of the second exit surface of the second exit end is S4, the following conditional expression is satisfied: S4>S1>S3≧S2

2. The lighting device according to claim 1 , wherein the first reflecting surface has a curved surface that curves radially outward with respect to the optical axis of the first light guide element.

3. the light source device includes a light source that emits light; and a fluorescent layer that converts the light emitted by the light source into the first light, 3. The lighting device according to claim 1, wherein the light emitting surface is an exit surface of the fluorescent layer.

4. the light source device includes a diffusion plate between the light source and the fluorescent layer that diffuses the light emitted from the light source, 4. The lighting device according to claim 3, wherein the light source is a semiconductor laser.

5. 10. The lighting device of claim 1, further comprising a reflective polarizer disposed between the first exit end and the second entrance end.

6. The lighting device according to claim 1 , wherein the first light guide element and the second light guide element are integrally formed.

7. The lighting device according to claim 1 , wherein the second light exit surface is rectangular.

8. The lighting device according to claim 1 , wherein the first light guide element and the second light guide element are made of metal.

9. The lighting device according to claim 1 , wherein the first light guide element has a hollow structure.

10. The lighting device according to claim 1 , wherein the second light guide element has a hollow structure.

11. The lighting device according to claim 1 , further comprising a collimator lens that collimates the first light emitted from the second light guide element.

12. The lighting device according to claim 1 ; a light modulation element that modulates the first light emitted from the illumination device to form a projection image; a projection lens that projects the projected image as an enlarged image; A projector comprising:

13. The area of the light emitting surface is 0.3 mm ２ ~20mm ２ and The area of the first exit surface is 0.15 mm ２ ~10mm ２ and The area of the second incident surface is 0.15 mm ２ ~10mm ２ and The area of the second exit surface is 57.1424 mm ２ ~14630.04mm ２ The projector according to claim 12,

14. 14. The projector according to claim 12, wherein the size of the effective display area of the light modulation element is 0.3 to 7.0 inches.

Images