Optical system, light source device and image projection device

Abstract

The present invention provides an optical system, a light source device and an image projection device that can be compactly constructed. The optical system (24), (25) and (26) are optical systems that include a dichroic mirror (24) that reflects blue light (an example of first light) emitted by a light source, and a fluorescent light region (26D) of a fluorescent light unit (26) that receives the blue light reflected by the dichroic mirror (24) and converts at least a portion of the blue light into fluorescent light of a wavelength different from that of the blue light and then emits the fluorescent light. The dichroic mirror (24) has an optical characteristic of transmitting the fluorescent light and has one end 33b located outside the fluorescent light beam and the other end (33a) located inside the fluorescent light beam. A reflector holder (30) is provided that holds the dichroic mirror (24) at one end (33b).

Description

Technical Field

[0001] The invention relates to an optical system, a light source device and an image projection device. Background Art

[0002] Patent document 1 discloses a projector comprising a light source device 63, a display element, a projector control mechanism, etc. The light source device 63 has a fluorescent wheel 71 having a plurality of segmented areas on a substrate that can be rotatably controlled, at least one of the segmented areas of the substrate being a reflecting portion, a fluorescent layer that receives excitation light and emits a predetermined wavelength band is formed on the reflecting portion, and the segmented areas where the fluorescent layer is not formed are transmissive portions that allow light to pass through; a first light source that irradiates the fluorescent body with excitation light in the visible light region; a second light source 82 that emits light of a wavelength band different from the fluorescence emitted from the fluorescent layer and the excitation light emitted from the first light source 72; a focusing optical system that focuses the light emitted from the fluorescent wheel 71 and the light emitted from the second light source 82 on the same optical path, and a light source control mechanism that controls the light emission of the first light source 72 and the second light source 82.

[0003] Patent document 2 discloses a light source device 2, which comprises: a laser light source 9 that emits excitation light; a fluorescence wheel 12 that transmits a portion of the excitation light while also receiving the excitation light to emit fluorescence, and reflects the excitation light and the fluorescence; a color dichroic mirror 10 arranged on the optical path of the excitation light between the laser light source 9 and the fluorescence wheel 12, and a 1 / 4 wave plate 11 arranged on the optical path of the excitation light between the fluorescence wheel 12 and the color dichroic mirror 10, the color dichroic mirror 10 having a polarization separation characteristic of reflecting the second polarization component of the excitation light and the fluorescence on the return path while transmitting the first polarization component of the excitation light on the outgoing path.

[0004] [Patent Document 1] (Japan) Patent No. 5803470 Summary of the invention

[0005] An object of the present invention is to provide an optical system, a light source device, and an image projection device that can be configured compactly.

[0006] A technical solution of the present invention relates to an optical system, which has an optical component that reflects a first light emitted by a light source, and a wavelength conversion portion into which the first light reflected by the optical component is incident and converts at least a portion of the first light into a second light having a wavelength different from that of the first light and then emits the second light. The optical system is characterized in that the optical component has an optical property of transmitting the second light, and has a first end located outside the beam of the second light, and a second end located inside the beam of the second light, and is provided with a holding component for holding the optical component outside the beam of the second light.

[0007] According to the present invention, it is possible to provide an optical system, a light source device, and an image projection device that can be configured compactly. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 FIG. 1 is a schematic diagram showing the optical path of blue laser light in a light source device according to an embodiment of the present invention.

[0009] Figure 2 FIG. 1 is a diagram schematically showing the optical path of fluorescent light in the light source device according to the present embodiment.

[0010] Figure 3A , Figure 3B FIG. 2 is an explanatory diagram of the arrangement of the dichroic mirrors according to the present embodiment.

[0011] Figure 4A , Figure 4B FIG. 2 is a diagram for explaining the structure of a fluorescent unit included in the light source device according to the present embodiment.

[0012] Figure 5A , Figure 5B FIG. 2 is a diagram for explaining a method of fixing the dichroic mirror according to the present embodiment.

[0013] Fig. 6A , Figure 6B FIG. 2 is an explanatory diagram of a modified example of the method of fixing the dichroic mirror according to the present embodiment.

[0014] Figure 7 FIG. 2 is an explanatory diagram of a dichroic mirror according to the present embodiment.

[0015] Fig. 8A , Figure 8B It is an explanatory diagram of a modification example of the fixing method involved in this embodiment.

[0016] Fig.9A , Fig. 9B It is an explanatory diagram of a modification example of the fixing method involved in this embodiment.

[0017] Fig.10 It is an explanatory diagram of a modification example of the fixing method involved in this embodiment.

[0018] Fig.11A , Fig. 11B It is an explanatory diagram of a modification example of the fixing method involved in this embodiment.

[0019] Fig. 12A , Fig. 12B It is an explanatory diagram of a modification example of the fixing method involved in this embodiment.

[0020] Fig.13 FIG. 1 is a schematic diagram showing the configuration of a projector device including a light source device according to the present embodiment. DETAILED DESCRIPTION

[0021] Figure 1 FIG. 2 is a schematic diagram showing the optical path of blue laser light in the light source device 20 according to the embodiment of the present invention.

[0022] like Figure 1 As shown, the light source device 20 has a laser light source (excitation light source) 21, a coupling lens 22, a first optical system 23, a color separation mirror 24 (an example of an optical part) as an example of an optical part, a second optical system 25 (an example of a light guiding optical system), a fluorescent unit 26 as an example of a wavelength conversion unit, a refractive optical system 27, and an optical channel 29 as an example of a light mixing element, which are arranged in sequence in the direction of light propagation.

[0023] The laser light source 21 is, for example, a plurality of light sources that emit laser light arranged in an array. The laser light source 21 emits, for example, light in a blue band (blue laser) whose luminous intensity is centered at 455 nm. Hereinafter, the blue laser is simply referred to as blue light. The blue light emitted from the laser light source 21 is linearly polarized light with a certain polarization direction, and is also used as excitation light for exciting the phosphor included in the phosphor unit 26 described later.

[0024] In addition, the light emitted from the laser light source 21 can be light of a wavelength that can excite the phosphor described later, and is not limited to light in the blue wavelength band. In addition, the laser light source 21 has a plurality of light sources, but is not limited to this, and may also be composed of a single light source. In addition, the laser light source 21 may be a configuration in which a plurality of light sources are arranged in an array on a substrate, but is not limited to this, and may also be other configurations.

[0025] The coupling lens 22 is a lens that receives the blue light emitted by the laser light source 21 and converts it into parallel light (collimated light). In addition, the parallel light mentioned below is not limited to completely collimated (parallelized) light, but includes the concept of roughly parallelized light. The number of coupling lenses 22 only needs to correspond to the number of light sources of the laser light source 21, and can be increased or decreased according to the increase or decrease of the number of light sources of the laser light source 21.

[0026] In the light source device 20 involved in this embodiment, a light source unit is constituted by these laser light sources 21 and coupling lenses 22. For example, the laser light source 21 is constituted by a plurality of laser diodes arranged in rows and columns. That is, the light source unit is constituted by these laser diodes and the coupling lens 22 arranged on the emission surface side of the laser diode.

[0027] The first optical system 23 has positive refractive power as a whole, and has a large-diameter lens 23a and a negative lens 23b in sequence from the laser light source 21 side toward the fluorescent body unit 26 side. The large-diameter lens 23a is an example of a large-diameter element, and is composed of a lens having positive refractive power and focusing and synthesizing the parallel light emitted from the coupling lens 22. The negative lens 23b is an example of a parallelization element, and is composed of a lens that converts the blue light focused by the large-diameter lens 23a into parallel light. The first optical system 23 reduces the diameter of the blue light (excitation light) incident from the coupling lens 22 as approximately parallel light and guides it to the dichroic mirror 24.

[0028] The dichroic mirror 24 is arranged obliquely with respect to the propagation direction of the blue light emitted from the first optical system 23. More specifically, the front end portion is arranged in a state of being inclined downward along the propagation direction of the blue light emitted from the first optical system 23. The dichroic mirror 24 has an optical characteristic of reflecting the blue light converted into substantially parallel light by the first optical system 23 and transmitting the fluorescent light (second color light, an example of the second color light) converted by the fluorescent body unit 26. For example, a coating having the above-mentioned optical characteristics is applied to the dichroic mirror 24.

[0029] The dichroic mirror 24 has a length shorter than the width of the first optical system 23. Since the dichroic mirror 24 is short, the light source device 20 can be miniaturized.

[0030] The refractive optical system 27 is composed of a lens that focuses the light (blue light and fluorescent light) emitted from the second optical system 25. The light (blue light and fluorescent light) emitted from the fluorescent body unit 26 passes through the dichroic mirror 24, is focused (refracted) by the refractive optical system 27, and is incident on the optical channel 29.

[0031] The optical path of blue light in the light source device 20 having such a structure (hereinafter appropriately referred to as "blue light path") is described. The blue light path refers to the optical path of light reflected by the reflective portion of the fluorescent unit 26 among the excitation light emitted by the laser light source 21.

[0032] The blue light emitted from the laser light source 21 is converted into parallel light by the coupling lens 22. The blue light emitted from the coupling lens 22 is focused and synthesized by the large-aperture lens 23a of the first optical system 23, and then converted into parallel light by the negative lens 23b. The blue light emitted from the negative lens 23b is reflected by the dichroic mirror 24 and directed toward the second optical system 25. The dichroic mirror 24 constitutes a reflecting surface 24a for emitting the blue light emitted from the laser light source 21. The point P of the center of the projection image of the above-mentioned excitation light is formed in the dichroic mirror 24.

[0033] As described above, the dichroic mirror 24 is configured to deviate from the optical axis of the second optical system 25 to the first optical system 23. Therefore, the blue light path is incident on a portion of the second optical system 25 (more specifically, the positive lens 25A) on the side of the first optical system 23. Then, the blue light approaches the optical axis of the second optical system 25 at an angle, and is emitted from the second optical system 25 (more specifically, the positive lens 25B). The blue light emitted from the second optical system 25 is incident on the fluorescent body unit 26.

[0034] Here, the blue light incident on the fluorescent body unit 26 is assumed to be incident on the reflection. The blue light incident on the reflection part is reflected by the mirror surface. The blue light reflected by the mirror surface of the reflection part is incident on the part of the second optical system 25 (more specifically, the positive lens 25B) on the opposite side of the first optical system 23. Then, the blue light moves away from the optical axis of the second optical system 25 at an angle, and is emitted from the second optical system 25 (more specifically, the positive lens 25A).

[0035] The blue light emitted from the second optical system 25 (more specifically, the positive lens 25A) does not intersect the dichroic mirror 24. The light beam of the blue light reflected by the mirror surface of the fluorescent unit 26 constitutes the light beam of the excitation light emitted from the fluorescent unit 26. Since the light beam of the blue light does not intersect the dichroic mirror 24, it is possible to suppress a decrease in light utilization efficiency.

[0036] Here, one end 33 b (an example of a first end) of the dichroic mirror 24 is an end away from the blue light emitted from the second optical system 25 , and the other end 33 a (an example of a second end) of the dichroic mirror 24 is an end close to the blue light beam emitted from the second optical system 25 .

[0037] The blue light that passes through the dichroic mirror 24 without intersecting is incident on the refractive optical system 27. Then, the blue light approaches the optical axis of the refractive optical system 27 at an angle and is incident on the light tunnel 29. After being reflected multiple times and uniformized inside the light tunnel 29, the blue light is incident on the illumination optical system disposed outside the light source device 20.

[0038] Figure 2 FIG. 1 is a diagram schematically showing the optical path of fluorescent light in the light source device according to the present embodiment.

[0039] The optical path of the fluorescent light in the light source device 20 (hereinafter appropriately referred to as the "fluorescent optical path") is described. Figure 2 In the figure, for the sake of convenience, a part of the optical path of the fluorescent light is omitted. The so-called fluorescent optical path refers to the optical path of the excitation light emitted by the laser light source 21, which is the light path traveled by the light after the wavelength is converted in the wavelength conversion part of the fluorescent body unit 26.

[0040] Before the blue light emitted from the laser light source 21 is guided to the fluorescent body unit 26, the fluorescent light path is the same as the above-mentioned blue light path. Here, the blue light incident on the fluorescent body unit 26 is assumed to be incident on the wavelength conversion unit. The blue light incident on the wavelength conversion unit acts on the fluorescent body as excitation light, and is converted into a wavelength by the fluorescent body, for example, while becoming fluorescent light in a wavelength region including yellow, it is Lambertian reflected by the action of the reflective coating and the fluorescent body layer.

[0041] The fluorescent light reflected by the wavelength conversion unit is converted into parallel light by the second optical system 25. The fluorescent light emitted from the second optical system 25 passes through the dichroic mirror 24 and enters the refractive optical system 27.

[0042] Here, one end 33 b of the dichroic mirror 24 is located outside the light beam of the fluorescent light, and the other end 33 a of the dichroic mirror 24 is located inside the light beam of the fluorescent light.

[0043] Then, the fluorescent light approaches the optical axis of the refractive optical system 27 at an angle and enters the light tunnel 29. After being reflected multiple times and made uniform inside the light tunnel 29, the fluorescent light enters the illumination optical system arranged outside the light source device 20.

[0044] Thus, in the light source device 20 according to the present embodiment, the optical path of the blue light emitted from the laser light source 21 is different before and after the reflection by the fluorescent unit 26. More specifically, the optical path of the blue light is formed in such a manner that the point of the center of the projection image of the blue light projected from the laser light source 21 onto the dichroic mirror 24 and the light beam of the blue light reflected from the fluorescent unit 26 do not intersect. Thus, since the light beam of the blue light emitted from the fluorescent unit 26 does not intersect the center of the projection image of the blue light emitted from the laser light source 21, it is possible to prevent the blue light from penetrating the same portion on the dichroic mirror 24, thereby suppressing the damage of the dichroic mirror 24 due to the increase in the light concentration density, and improving the reliability.

[0045] In addition, since it is not necessary to prepare a special optical element such as a phase retarder or a polarization separation element (polarization beam splitter) in order to separate the optical path of the excitation light emitted from the fluorescent body unit 26, the number of parts can be reduced, the manufacturing cost can be reduced, and the light source device 20 can be miniaturized. Furthermore, since optical components that operate the polarization of the phase retarder and the polarization separation element are not used, it is possible to suppress the reduction in light utilization efficiency caused by the reflectivity, transmittance, and absorptivity of the optical components.

[0046] Furthermore, in the light source device 20 involved in the present embodiment, the blue light emitted from the laser light source 21 is linearly polarized light with a certain polarization direction. In addition, the light source unit having a plurality of laser light sources 21 is configured so that the directions of the linearly polarized light are all the same. Therefore, the directions of the linearly polarized light of the light emitted from the light source unit are consistent. The direction of the linearly polarized light can be determined by the direction in which the light source unit is configured. When the light source unit is tilted corresponding to the tilt of the light channel 29, the direction of the linearly polarized light changes. In this way, when the direction of the linearly polarized light changes, when the polarized light is manipulated by a polarized light separation element, etc., the light utilization efficiency when passing through the polarized light separation element may be reduced. In the light source device 20 involved in the present embodiment, since a structure for manipulating polarized light is not adopted, a reduction in light utilization efficiency caused by the tilt of the laser light source 21 can be prevented.

[0047] FIG3 is an explanatory diagram showing the arrangement of the dichroic mirror 24 according to the present embodiment. Figure 1 and Figure 2 FIG3 is a diagram of the color dichroic mirror 24 and the second optical system 25 as seen from above in the vertical direction of the dichroic mirror 24. The fluorescent light emitted from the fluorescent body unit 26 propagates from the back side to the front side of the paper surface of FIG3, and after being converted into a fluorescent light beam 71 by the second optical system 25 into parallel light, it is emitted toward the refractive optical system 27. The color dichroic mirror 24 is configured to overlap with the fluorescent light beam 72 emitted from the positive lens 25A of the second optical system 25. The color dichroic mirror 24 is configured so that one end 33b thereof is located outside the fluorescent light beam 72. The other end 33a of the color dichroic mirror 24 is configured in the fluorescent light beam 72.

[0048] The blue light reflected by the fluorescent body unit 26 enters the second optical system 25, and propagates from the back side to the front side of the paper of FIG. 3 from the positive lens 25A as a blue light beam 71, and enters the refractive optical system 27. The dichroic mirror 24 is arranged outside the blue light beam 71 so as not to overlap with the blue light beam 71. The dichroic mirror 24 is arranged on the opposite side of the blue light beam 71 with respect to the optical axis 25C of the second optical system 25.

[0049] In the fluorescent light beam 72, the fluorescent light overlapping with the dichroic mirror 24 passes through the dichroic mirror 24, but a part of it is reflected or absorbed by the dichroic mirror, so the intensity becomes weak. Therefore, the fluorescent light beam 72 has an asymmetric intensity distribution with respect to the optical axis 25C of the second optical system 25. In the configuration of the dichroic mirror shown in FIG3, the intensity is weak on the side of the end 33b of the optical axis 25C (the left side of FIG3), and the intensity is strong on the opposite side of the end 33b of the optical axis 25C (the right side of FIG3).

[0050] Figure 3AThe configuration is an example in which the center line 33 in the short-side direction of the dichroic mirror 24 overlaps the optical axis 25C of the second optical system 25. With such a configuration, the intensity distribution of the fluorescent light beam 72 can be made symmetrical with respect to the center line 33 in the short-side direction of the dichroic mirror 24, so that the intensity distribution of the fluorescent light emitted from the refractive optical system 27 can be made more uniform.

[0051] Figure 3B This is an example of disposing the center line of the short side direction of the dichroic mirror 24 offset from the optical axis 25C. Since the center of the dichroic mirror 24 is offset upward relative to the optical axis 25C in FIG. 3b, the intensity distribution of the fluorescent light beam 72 becomes stronger on the lower right side of FIG. 3b. At this time, without changing the direction of the dichroic mirror 24, the optical path of the blue light beam 71 remains unchanged. Therefore, Figure 3B The configuration of the dichroic mirror 24 can adjust the intensity distribution of the fluorescent light beam 72 regardless of the configuration of the light source 21 or the first optical system 23. Thus, the angular distribution of the fluorescent light emitted from the refractive optical system 27 can be adjusted according to the configuration of the optical channel 29. At this time, as described above, the distribution of the fluorescent light can be adjusted without being affected by the configuration of the light source 21 or the first optical system 23.

[0052] Figure 4A , Figure 4B FIG. 2 is an explanatory diagram of the structure of the fluorescent body unit included in the light source device according to the present embodiment. Figure 4A In FIG. 1 , the phosphor unit 26 is shown from the incident direction of the blue light. Figure 4B , the fluorescent unit 26 is shown from a direction orthogonal to the incident direction of the blue light. Figure 4A , Figure 4B The structure of the fluorescent body unit 26 shown in the figure is shown as an example, and it is not limited to this, and it can be changed suitably.

[0053] like Figure 4A , Figure 4B As shown, the fluorescent body unit 26 has a disk member (substrate) 26A and a drive motor (drive unit) 26C that drives the disk member 26A to rotate about a straight line perpendicular to the plane of the disk member 26A as a rotation axis 26B. The disk member 26A can be, for example, a transparent substrate or a metal substrate (aluminum substrate, etc.), but is not limited thereto.

[0054] The majority of the circumferential direction of the fluorescent body unit 26 (disk component 26A) (angle range greater than 270° in the first embodiment) is divided into a fluorescent area 26D, and a small portion of the circumferential direction (angle range less than 90° in the first embodiment) is divided into an excitation light reflection area 26E. In addition, the excitation light reflection area 26E is a first area that reflects (or diffusely reflects) the excitation light reflected by the dichroic mirror 24, constituting an example of a reflection part. The fluorescent area 26D is an area that converts the excitation light reflected by the dichroic mirror 24 and emits fluorescent light, constituting an example of a wavelength conversion part. The fluorescent area 26D is composed of a reflective coating 26D1, a fluorescent body layer 26D2, and an anti-reflection coating (AR coating) 26D3 stacked in sequence from the lower layer side to the upper layer side.

[0055] The reflective coating 26D1 has the property of reflecting light in the wavelength region of the fluorescent light (luminescent light) of the fluorescent layer 26D2. When the disk member 26A is formed of a metal substrate with a high reflectivity, the reflective coating 26D1 may be omitted. In other words, the disk member 26A may also have the function of the reflective coating 26D1.

[0056] The phosphor layer 26D2 may be, for example, a phosphor material dispersed in an organic / inorganic binder, a phosphor material crystal formed directly, or a rare earth phosphor such as Ce:YAG system. In addition, the phosphor layer 26D2 constitutes an example of a wavelength conversion component that converts at least a portion of the excitation light into fluorescent light of a wavelength different from the excitation light and emits the fluorescent light. The wavelength band of the fluorescent light (luminous light) of the phosphor layer 26D2 may be, for example, yellow, blue, green, and red wavelength bands. In the first embodiment, the case of using fluorescent light (luminous light) having a yellow wavelength band is used as an example. In addition, in the present embodiment, a phosphor is used as the wavelength conversion element, but phosphors, nonlinear optical crystals, etc. may also be used.

[0057] The anti-reflection coating 26D3 has a property of preventing light from being reflected on the surface of the phosphor layer 26D2.

[0058] A reflective coating (reflective surface) 2E1 is stacked on the excitation light reflecting region 26E, and the reflective coating 26E1 has the characteristic of reflecting light in the wavelength region of the blue light guided from the second optical system 25. When the disk member 26A is composed of a metal substrate with a high reflectivity, the reflective coating 26E1 may be omitted. In other words, the disk member 26A may also have the function of the reflective coating 26E1.

[0059] By driving the motor 26C to rotate the disk member 26A, the irradiation position of the blue light on the fluorescent body unit 26 moves with time. As a result, a part of the blue light (first color light, an example of the first color light) incident on the fluorescent body unit 26 is converted into fluorescent light (second color light) having a wavelength different from that of the blue light (first color light) in the fluorescent area (wavelength conversion area) 26D and emitted. On the other hand, the other part of the blue light incident on the fluorescent body unit 26 is directly reflected and emitted as blue light in the excitation light reflection area 26E.

[0060] In addition, there is freedom in the number and range of the fluorescent regions 26D and the excitation light reflecting regions 26E, and various design changes can be made. For example, two fluorescent regions and two excitation light reflecting regions may be alternately arranged at intervals of 90° in the circumferential direction.

[0061] Figure 5A , Figure 5B FIG. 2 is a diagram for explaining a method of fixing the dichroic mirror 24 according to the present embodiment.

[0062] The dichroic mirror 24 has an optically used region and an optically unused region for holding the dichroic mirror 24, and is fixed by a mirror holder 30 (an example of a holding member) that supports (holds) the dichroic mirror 24 and a mirror pressing member 31 that presses the dichroic mirror 24. In addition to the structure shown in the figure, the fixing method may be adhesive fixing, direct fixing of the dichroic mirror 24 by screws, etc.

[0063] like Figure 2 As shown, one end 33b of the dichroic mirror 24 is located outside the light beam of the fluorescent light emitted from the second optical system 25. The one end 33b is included in an optically unused area, that is, an area that does not need to function optically. The reflector holder 30 holds the area that does not need to function optically.

[0064] like Figure 2 As shown, the other end 33 a of the dichroic mirror 24 is located within the light beam of the fluorescent light emitted from the second optical system 25 , and is not held by the mirror holder 30 .

[0065] like Figure 5B As shown, an opening 30A is formed in the reflector bracket 30, from which Figure 2 The light beam of fluorescent light emitted from the second optical system 25 shown passes through the opening 30A.

[0066] In addition, from Figure 1 The blue light emitted from the second optical system 25 shown in the figure passes through a region of the opening 30A of the mirror holder 30 that does not overlap with the dichroic mirror 24 .

[0067] Fig. 6A , Figure 6B FIG. 2 is an explanatory diagram of a modified example of the method of fixing the dichroic mirror 24 according to the present embodiment.

[0068] exist Figure 5A , Figure 5B In the embodiment, the reflector holder 30 holds the dichroic mirror 24 in a manner that one end 33b is exposed, but Fig. 6A , Figure 6B In the figure, the reflector holder 30 holds the dichroic mirror 24 in such a manner that one end 33b is not exposed.

[0069] Figure 7 FIG. 2 is an explanatory diagram of the dichroic mirror 24 according to the present embodiment.

[0070] The relationship between the dichroic mirror 24, the first straight line 32 in the X direction passing through the reflector, and the second straight line 33 in the Y direction passing through the reflector is described below. The dichroic mirror 24 implements optical functions such as polarized light separation film, wavelength selective filter function, or reflection film on the surface of a transparent substrate such as glass or sapphire. In particular, in the dichroic mirror area that transmits or reflects according to the wavelength, an optical film that transmits or reflects according to the wavelength region is provided on the surface. Two virtual straight lines (32, 33) are defined on the surface.

[0071] The second straight line 33 is a straight line along the long side of the dichroic mirror 24, and the first straight line 32 is a straight line along the short side of the dichroic mirror 24, and the two are orthogonal to each other. The first straight line 32 is the center line of the long side of the dichroic mirror 24, and the second straight line 33 is also the center line of the short side of the dichroic mirror 24.

[0072] The ends of the optical element exist on two imaginary straight lines, namely, the ends 33a, 33b, 32a, and 32b.

[0073] As described above, the one end 33 b is located outside the light beam of the fluorescent light emitted from the second optical system 25 , and is held by the mirror holder 30 .

[0074] As described above, the other end 33 a is located within the light flux of the fluorescent light emitted from the second optical system 25 , and is not held by the mirror holder 30 .

[0075] Furthermore, if Figure 5A , Figure 5B and Fig. 6A , Figure 6B As shown, the one end 32 b and the other end 32 a are also located within the light beam of the fluorescent light emitted from the second optical system 25 , and are not held by the mirror holder 30 .

[0076] The position where the blue light emitted from the laser light source 21 is incident on the reflection surface 24a of the dichroic mirror 24 may also be configured in a manner that is centered in the direction of the imaginary first straight line 32. The other end 33a of the dichroic mirror 24 is located in the light beam of the fluorescent light and also in the light beam of the blue light. Therefore, the temperature of the reflection surface 24a side of the dichroic mirror 24 rises by being irradiated with the fluorescent light and the blue light. The dichroic mirror 24 is deformed due to the temperature rise on one side, and the reflection surface 24a is bent. Even in the case where the reflection surface 24a is bent, the change in the angle of the light beam relative to the blue light near the center portion in the direction of the first straight line 32 of the reflection surface 24a becomes smaller than that of the end portion in the direction of the first straight line 32 of the reflection surface 24a (near the end 32a or 32b of the reflection surface 24a). Therefore, even if the temperature of the dichroic mirror 24 rises, the change in the emission direction of the blue light reflected by the reflection surface 24a becomes smaller. As a result, the optical system of this embodiment can stabilize the emission direction of the blue light beam.

[0077] In order to make the center of the blue light beam the center in the direction of the first straight line 32 of the dichroic mirror 24, the first optical system 23 and the dichroic mirror can be arranged in such a way that the optical axis of the first optical system 23 intersects the reflecting surface 24a in the center in the direction of the imaginary line 32 of the dichroic mirror 24. Fig. 6A , Figure 6B To explain a modified example of FIG. 2 , the intersection of the first straight line 32 and the second straight line 33 of the dichroic mirror 24 intersects with the optical axis of the first optical system.

[0078] The imaginary first straight line 32 and the second straight line 33 are defined to be at an angle of approximately 90 degrees to each other, but are not limited thereto.

[0079] In addition, the optical element is described using a rectangular shape as an example, but it may also be a square, polygon, circle, or ellipse, as long as the shape of the optical element is designed to be suitable for the unit composition.

[0080] Fig. 8A , Figure 8B1 is an explanatory diagram of a modified example of the fixing method of the dichroic mirror 24 involved in the present embodiment. The dichroic mirror 24 is clamped by a mirror holder 30 and a mirror pressure plate 31, and is fixed by fastening the mirror pressure plate 31 to the mirror holder 30 with a screw 35. A recess 34c corresponding to the shape of the dichroic mirror 24 is provided in the mirror holder 30. The angle of the reflecting surface 24a is determined by the bottom surface of the recess 34c abutting against the reflecting surface 24a of the dichroic mirror 24. The recess 34c is provided with walls in three directions except for the opposite side of the one end 33b side of the dichroic mirror. The walls of these recesses 34c are fitted with the side surfaces of the dichroic mirror 24. Furthermore, a protrusion 34a is provided on the bottom surface of the recess 34c, and a hole 34b is provided in the dichroic mirror 24. The protrusion 34a and the hole 34b are engaged with each other, so that the position in the direction parallel to the reflecting surface 24a of the dichroic mirror 24 can be determined. Here, the recess 34c, the hole 34b, and the protrusion 34a are examples of positioning components that determine the position of the dichroic mirror 24 relative to the mirror holder 30. With these positioning components, even when an impact or vibration is applied to the optical system, the horizontal positional deviation will not occur, so that the blue light beam and the dichroic mirror will not interfere with each other, and the light amount of the blue light emitted by the optical system can be stabilized.

[0081] Fig.9A , Fig. 9B FIG. 2 is an explanatory diagram of another modified example of the method of fixing the dichroic mirror 24 according to the present embodiment. Fig. 8A , Figure 8B Similarly, the mirror holder 30 and the mirror pressing plate 31 are clamped and positioned and fixed by fitting with the recessed portion 34c. A protrusion 34d is provided on the side of the recessed portion of the mirror holder 30, and a cutout 34e is provided on the side of the dichroic mirror 24. The cutout 34e is fitted with the protrusion 34d, so that the positions of the dichroic mirror 24 and the mirror holder 30 can be determined.

[0082] Fig.10 It is explained in Fig.9A , Fig. 9B In the embodiment of FIG. 1 , a diagram showing a modified example of the force-applying member is added. Fig.10 The dichroic mirror 24 of the modified example is provided with Fig.9A , Fig. 9BThe cutout portion 34h is the same as a modified example. When viewed from a direction perpendicular to the reflecting surface 24a of the dichroic mirror, the cutout portion 34h is in a V-shape. A force-applying component 34f is provided on the reflector bracket 30. A protrusion 34g is provided on the force-applying component 34f to engage with the cutout portion 34h. The force-applying component 34f applies force to the dichroic mirror 24 through a force-applying mechanism such as a leaf spring (not shown) to press it onto the wall portion 34i, which is an example of a reference surface of the reflector bracket 30. Here, the shape of the protrusion 34g is semicircular, and the arc of the protrusion 34g abuts against the two sides of the V-shape of the cutout portion 34h at two points. The dichroic mirror 24 and Fig.9A , Fig. 9B Similarly, the mirror holder 30 and the mirror pressing plate 31 are clamped and fixed. By providing the biasing member 34f in this way, even if the outer shape of the dichroic mirror 24 changes due to temperature changes, the position of the dichroic mirror 24 can be normally maintained.

[0083] Fig.11A , Fig. 11B FIG. 2 is an explanatory diagram of another modified example of the method of fixing the dichroic mirror 24 according to the present embodiment. Fig. 8A , Figure 8B Similarly to the modified example, the dichroic mirror 24 is fitted into the recess 34c and fixed by clamping the mirror holder 30 and the mirror pressing plate 31. Fig.11A , Fig. 11B In the modified example, the end face 34j and the end face 34k of the color dichroic mirror 24 abut against the wall portion 34i and the wall portion 34m of the recess. The end portion 34k is not parallel to the end portion 34j, and the wall portion 34m is not parallel to the wall portion 34i. After the color dichroic mirror 24 is configured to fit into the recess 34c, a force is applied to the side of one end 33b of the color dichroic mirror 24 in the direction indicated by the arrow 34n by a force-applying mechanism not shown in the figure. Since the end faces 34j and the end faces 34k are conical in shape, and the wall portions 34i and the wall portions 34m are conical in shape, the position of the color dichroic mirror 24 in a direction parallel to the reflecting surface 24a is determined by applying force to the color dichroic mirror 24. Since the color dichroic mirror 24 is always applied with force, even if the position is temporarily shifted due to vibration or impact, it will be positioned again due to the force, so that a stable position can be maintained for a long time. In addition, due to Fig.11A , Fig. 11B The dichroic mirror 24 does not require processing of a cutout portion or a hole of a special shape, so the dichroic mirror can be manufactured simply.

[0084] Fig. 12A , Fig. 12B FIG. 2 is an explanatory diagram of another modified example of the method of fixing the dichroic mirror 24 according to the present embodiment. Fig. 12A , Fig. 12B Variations of Fig.10The fixing method shown in FIG. 1 is similar to that of fixing the dichroic mirror 24 by clamping the mirror support 30 and the mirror pressure plate 31. The difference is that Fig. 12B As shown, a heat transfer component 36 is provided between the dichroic mirror 24 and the reflector bracket 30, and between the dichroic mirror 24 and the reflector pressing plate 31. The heat transfer component 36 is arranged to be in close contact with the dichroic mirror 24 above and below, and is clamped together with the dichroic mirror 24 by the reflector bracket 30 and the reflector pressing plate 31. The heat transfer component 36 arranged between the reflector bracket 30 and the dichroic mirror 24 is in thermal contact with the dichroic mirror 24 and the reflector bracket 30 respectively. Similarly, the heat transfer component arranged between the reflector pressing plate 31 and the dichroic mirror 24 is in thermal contact with the dichroic mirror 24 and the reflector pressing plate 31 respectively. Since the dichroic mirror 24 is heated by the incident blue light or fluorescent light, the temperature rises. In particular, the fluorescent light emitted from the fluorescent body unit 26 easily heats the dichroic mirror 24 because it contains infrared rays. Therefore, the surface of the dichroic mirror 24 on the light incident side is heated by the incident blue light or fluorescent light and the temperature rises. When the temperature of the dichroic mirror 24 rises, the dichroic mirror 24 will be deformed due to the thermal expansion of the material of the substrate or the material of the coating of the dichroic mirror 24. In particular, when the temperature of one side of the dichroic mirror 24 becomes high, the dichroic mirror 24 will be warped or deformed by the stress caused by the thermal expansion of the one side of the dichroic mirror 24. When the dichroic mirror is deformed, the angle of the reflecting surface 24a will change, so the direction of reflecting the incident blue light will change. In addition, when the temperature of the dichroic mirror 24 changes greatly, the position of the dichroic mirror 24 relative to the reflector bracket will change, thereby causing the problem of positional displacement.

[0085] because Fig. 12A , Fig. 12B In a modified example, the heat transfer member 36 is disposed between the dichroic mirror 24 and the mirror holder 30 and the mirror pressure plate 31, so that the heat of the dichroic mirror 24 can be effectively transferred to the mirror holder 30 and the mirror pressure plate 31, thereby reducing the temperature rise of the dichroic mirror 24. As a result, the positional deviation or deformation of the dichroic mirror 24 can be reduced.

[0086] The material of the heat transfer member 36 is preferably a material with high thermal conductivity and high adhesion to the dichroic mirror 24 and the mirror holder 30. For example, it is preferable to use a relatively low-rigidity metal such as aluminum, tin, or solder, or a thin film-shaped resin with high thermal conductivity or a rubber material with high thermal conductivity.

[0087] The heat transfer member 36 may be disposed on both sides of the dichroic mirror 24 or on one side. When the heat transfer member 36 is disposed on both sides, the heat of the dichroic mirror 24 can be effectively transferred, so that the temperature rise of the dichroic mirror 24 can be suppressed. When the heat transfer member 36 is disposed between the dichroic mirror 24 and the mirror pressing plate 31, the heat of the dichroic mirror 24 is difficult to transfer to the mirror holder side, so the temperature rise of the mirror holder 30 can be suppressed. In this case, since the deformation of the mirror holder due to the temperature rise of the mirror holder 30 can be suppressed, the position of the dichroic mirror 24 is stabilized.

[0088] Fig. 12A , Fig. 12B The mirror pressing plate 31 or the mirror bracket 30 may be a heat dissipation component. A heat sink for heat dissipation may be formed on the mirror pressing plate 31 or the mirror bracket 30, and a fan for air cooling or a flow path for cooling water for water cooling may also be formed.

[0089] Fig.13 1 is a schematic diagram showing the configuration of a projector device (image projection device) 1 including a light source device 20 according to the first embodiment.

[0090] The projector device 1 includes a housing 10, a light source device 20, an illumination optical system 130, an image forming element (image display element) 40, a projection optical system 50, and a cooling device 60. The housing 10 accommodates the light source device 20, the illumination optical system 130, the image forming element 40, the projection optical system 50, and the cooling device 60.

[0091] The illumination optical system 130 illuminates the image forming element 40 substantially uniformly using the light uniformized by the light channel 29 of the light source device 20. The illumination optical system 130 includes, for example, one or more lenses and one or more reflecting surfaces.

[0092] The image forming element 40 forms an image by modulating the light (the light from the light source optical system of the light source device 20) illuminated by the illumination optical system 130. The image forming element 40 is composed of, for example, a digital micromirror device (DMD) or a liquid crystal display element. The image forming element 40 drives a micro mirror in synchronization with the light (blue light, green light, red light, yellow light) irradiated by the illumination optical system 130 to generate a color image.

[0093] The projection optical system 50 enlarges and projects the image (color image) formed by the image forming element 40 onto a screen (projection surface). The projection optical system 50 includes, for example, one or more lenses. The cooling device 60 cools the various elements and devices in the projector device 1 that are heated.

[0094] Conclusion

[0095] As described above, the optical system 24, 25, 26 according to one embodiment of the present invention is an optical system including a dichroic mirror 24 (an example of an optical component) that reflects blue light (an example of first light) emitted from a light source, and a fluorescent light region 26D (an example of a wavelength conversion unit) of a fluorescent body unit 26 into which the blue light reflected by the dichroic mirror 24 is incident and at least a part of the blue light is converted into fluorescent light (an example of second light) having a wavelength different from that of the blue light and then emitted, the dichroic mirror 24 having an optical characteristic of transmitting the fluorescent light and having one end 33b (an example of a first end) located outside the light beam of the fluorescent light and the other end 33a (an example of a second end) located inside the light beam of the fluorescent light, and a reflector holder 30 (an example of a holding component) that holds the dichroic mirror 24 outside the light beam of the fluorescent light is provided. As an example, the reflector holder 30 holds the dichroic mirror 24 by the one end 33b.

[0096] Thus, the optical system can be configured more compactly compared to the case where both ends of the dichroic mirror 24 are held outside the light flux of the fluorescent light.

[0097] The other end 33a is located on the opposite side of the one end 33b. Thus, the optical system can be configured compactly in the direction connecting the other end 33a and the one end 33b.

[0098] The second end portion located in the fluorescent light beam includes not only the other end 33a located on the opposite side of the one end 33b, but also the one end 32b and the other end 32a located on the straight line 32 orthogonal to the straight line 33 connecting the one end 33b and the other end 33a. Thus, the optical system can be compactly configured in the direction of the straight line 33 and the direction of the straight line 32.

[0099] The center position of the blue light incident on the dichroic mirror 24 is located at the midpoint between the one end 32b and the other end 32a. Therefore, even if the temperature of the dichroic mirror 24 rises, the emission direction of the blue light reflected by the reflection surface 24a changes less, thereby stabilizing the emission direction of the blue light beam.

[0100] The dichroic mirror 24 is not held at the other end 33a, thereby preventing the quality of the fluorescent light from being deteriorated due to the provision of a holding member at the other end 33a.

[0101] The dichroic mirror 24 is not held at a portion located within the light beam of the fluorescent light, thereby preventing the quality of the fluorescent light from being degraded due to the provision of a holding member.

[0102] The holding structure of the one end 33 b of the dichroic mirror 24 which does not need to function optically is preferably held by bonding or sandwiching.

[0103] It is preferable to provide a structure for protecting the end 33 b of the dichroic mirror 24 that does not need to function optically and the portion of the dichroic mirror 24 that functions optically.

[0104] The fluorescent body unit 26 has an excitation light reflecting region 26E (an example of a reflecting portion) that reflects the blue light reflected by the dichroic mirror 24 , and the dichroic mirror 24 is located outside the light beam of the blue light reflected by the excitation light reflecting region 26E.

[0105] Thus, the dichroic mirror 24 prevents the quality of the blue light reflected by the excitation light reflecting region 26E from being degraded.

[0106] The dichroic mirror 24 is not held at the other end 33a close to the end of the blue light beam reflected by the excitation light reflecting area 26E. Thus, compared with the case where the dichroic mirror 24 is held at the other end 33a close to the end of the blue light beam reflected by the excitation light reflecting area 26E, the optical system can be constructed in a compact manner.

[0107] The dichroic mirror 24 and the reflector holder 30 may also include a hole 34a and a protrusion 34b as positioning parts for determining the relative positions. Thus, the position of the dichroic mirror 24 is stabilized by the engagement of the hole 34b of the dichroic mirror with the protrusion 34a of the reflector holder, and the quality of the blue light reflected by the dichroic mirror 24 can be prevented from being reduced.

[0108] The dichroic mirror 24 may include a cutout 34e as a positioning portion, and the mirror holder 30 may include a protrusion 34d that fits into the cutout 34e. This prevents the dichroic mirror 24 from being displaced relative to the mirror holder 30, and prevents the quality of the blue light reflected by the dichroic mirror 24 from being degraded.

[0109] The mirror holder 30 may include an urging member 34f for urging the dichroic mirror 24. Thus, the dichroic mirror 24 is urged to come into contact with the reference surface 34i of the mirror holder 30, thereby stabilizing the position of the dichroic mirror 24 and preventing degradation of the quality of blue light.

[0110] A heat transfer member 36 is provided between the mirror holder 30 and the dichroic mirror 24. Alternatively, the mirror holder 30 includes a heat dissipation member for dissipating the heat of the dichroic mirror 24. Thus, positional deviation or deformation of the dichroic mirror 24 can be reduced.

[0111] A second optical system 25 (an example of a light guiding optical system) is provided between the dichroic mirror 24 and the fluorescent region 26D, and guides the blue light reflected by the dichroic mirror 24 to the fluorescent region 26D. The second optical system 25 converts the fluorescent light incident from the fluorescent region 26D into parallel light and emits the parallel light. The optical axis of the second optical system 25 is located between one end 32b and the other end 32a of the dichroic mirror 24. Thus, the intensity distribution of the fluorescent light beam 72 can be made symmetrical with respect to the center line 33 of the short side direction of the dichroic mirror 24.

[0112] A second optical system 25 is provided between the dichroic mirror 24 and the fluorescent region 26D, and guides the blue light reflected by the dichroic mirror 24 to the fluorescent region 26D. The second optical system 25 converts the fluorescent light incident from the fluorescent region 26D into parallel light and emits the parallel light. The optical axis of the second optical system 25 is offset from the middle of one end 32b and the other end 32a of the dichroic mirror 24. Thus, the intensity distribution of the fluorescent light beam 72 can be adjusted regardless of the arrangement of the light source 21 or the first optical system 23.

[0113] The light source device 20 can be configured compactly by including the laser light source 21 (an example of a light source) and the above-mentioned optical system.

[0114] The projector device 1 (an example of an image projection device) can be compactly constructed by having a light source device 20, an illumination optical system 130 that guides light emitted from the light source device 20 toward an image display element, and a projection optical system 50 that projects an image generated through an image display element 40 using the light guided by the illumination optical system 130.

Claims

1. An optical system comprising an optical component for reflecting first light emitted by a light source, and a wavelength conversion unit into which the first light reflected by the optical component is incident and into which at least a portion of the first light is converted into second light of a wavelength different from that of the first light, and then emitted, wherein: The optical component has an optical property of transmitting the second light, and has a first end located outside the beam of the second light, and a second end, a third end, and a fourth end located within the beam of the second light, the first end and the second end are respectively located at two ends of the optical component, the third end and the fourth end are respectively located at the other two ends of the optical component, and the other two ends where the third end and the fourth end are located are different from the two ends where the first end and the second end are located, and a holding component is provided to hold the optical component in an area outside the beam of the second light including the first end; wherein, The holding member is used to hold the first end portion, but is not used to hold the second end portion, the third end portion, and the fourth end portion.

2. The optical system according to claim 1, characterized in that: The center position of the first light incident on the optical component is located at a midpoint between the third end and the fourth end.

3. The optical system according to any one of claims 1 and 2, characterized in that: The optical component is not retained at the second end.

4. The optical system according to any one of claims 1 and 2, characterized in that: A portion of the optical component located within the light beam of the second light is not held.

5. The optical system according to any one of claims 1 and 2, characterized in that: The wavelength conversion unit includes a reflection unit for reflecting the first light. The optical component is located outside the light beam of the first light reflected by the reflecting portion.

6. The optical system according to claim 5, characterized in that: The second end portion is an end portion close to the light beam of the first light reflected by the reflecting portion.

7. The optical system according to claim 6, characterized in that: The optical component has a reflecting surface that reflects the first light, Furthermore, the optical component has a positioning portion to determine the position of the optical component relative to the holding component in a direction parallel to the reflection surface.

8. The optical system according to claim 7, characterized in that: The holding member includes a biasing member that biases the optical member in a direction parallel to the reflecting surface.

9. The optical system according to any one of claims 6 to 8, characterized in that: The holding member includes a heat transfer member between the holding member and the optical member.

10. The optical system according to any one of claims 6 to 8, characterized in that: The holding member includes a heat dissipation member that dissipates heat of the optical member.

11. The optical system according to claim 1, characterized in that: A light guiding optical system is provided between the optical component and the wavelength converter for guiding the first light reflected by the optical component to the wavelength converter. The light guide optical system converts the second light incident from the wavelength conversion unit into parallel light and emits the parallel light. The optical axis of the light guiding optical system is located between the third end and the fourth end of the optical component.

12. The optical system according to claim 1, characterized in that: A light guiding optical system is provided between the optical component and the wavelength converter to guide the first light reflected by the optical component to the wavelength converter. The light guide optical system converts the second light incident from the wavelength conversion unit into parallel light and emits the parallel light. The optical axis of the light guiding optical system is offset from a middle portion between the third end portion and the fourth end portion of the optical component.

13. A light source device, characterized in that include: A light source and an optical system as claimed in any one of claims 1 to 12.

14. An image projection device, characterized in that include: The light source device according to claim 13; an illumination optical system for guiding the light emitted from the light source device toward the image display element, and A projection optical system projects an image generated by the image display element using the light guided by the illumination optical system.

Images