Optical system, light source device and image display device

Abstract

To provide an optical system, a light source device and an image display device that can be constituted in a compact manner.SOLUTION: Optical systems 24, 25 and 26 are the optical systems that comprise: a dichroic mirror 24 which reflects blue light (an example of first light) emitted from a light source; and a fluorescent region 26D of a phosphor unit 26 into which the blue light reflected by the dichroic mirror 24 injects and which converts at least a portion of the blue light to fluorescent light having wavelength being different from the blue light to emit. The dichroic mirror 24 comprises: one end 33b that has an optical characteristic being transparent for the fluorescent light and that is positioned out of a light beam of the fluorescent light; and the other end 33a that is positioned within the light beam of the fluorescent light, and a mirror holder 30 holding the dichroic mirror 24 at the one end 33b is provided.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to an optical system, a light source device, and an image display device. [Background technology]

[0002] Patent Document 1 discloses a projector including a light source device 63, a display element, a projector control means, etc., in which the light source device 63 has a plurality of segment areas on a rotationally controllable base material, at least one of the segment areas of the base material is a reflective area, a phosphor layer is formed on the reflective area and receives excitation light to emit light of a predetermined wavelength band, and the segment areas on which the phosphor layer is not formed are transparent areas that transmit light, a first light source that irradiates excitation light in the visible light range to the phosphor, a second light source 82 that emits light of a wavelength band different from the fluorescent light emitted from the phosphor 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 means 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 comprising a laser light source 9 that emits excitation light, a phosphor wheel 12 that transmits a portion of the excitation light and emits fluorescence upon receiving the excitation light, and reflects the excitation light and the fluorescence, a dichroic mirror 10 provided on the optical path of the excitation light between the laser light source 9 and the phosphor wheel 12, and a 1 / 4 wavelength plate 11 provided on the optical path of the excitation light between the phosphor wheel 12 and the dichroic mirror 10, wherein the dichroic mirror 10 has a polarization separation characteristic that transmits a first polarized component of the excitation light on the outbound path and reflects the second polarized component of the excitation light and the fluorescence on the return path. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present invention is to provide an optical system, a light source device, and an image display device that can be configured compactly. [Means for solving the problem]

[0005] The invention of claim 1 provides an optical system including an optical member that reflects a first light emitted from a light source, a wavelength conversion unit that receives the first light reflected by the optical member and converts at least a part of the first light into a second light having a wavelength different from the first light and emits the second light, and a light guiding optical system between the optical member and the wavelength conversion unit that guides the first light reflected by the optical member to the wavelength conversion unit, and a holding member that holds the optical member, wherein the first light emitted from the light source is reflected by the optical member and enters the light guiding optical system from the light source side with respect to the optical axis of the light guiding optical system, passes through the light guiding optical system at an angle approaching the optical axis of the light guiding optical system and enters the wavelength conversion unit, and of the first light that is emitted from the light guiding optical system and enters the wavelength conversion unit, the first light that enters a reflecting portion in the wavelength conversion unit is specularly reflected by the reflecting portion and is guided to the light guiding optical system from the opposite side to the light source side with respect to the optical axis of the light guiding optical system. the optical member has an optical property of transmitting the second light; the optical member has an optical characteristic of transmitting the second light; the optical member has an optical path from when the first light is emitted from the light source to when the first light is incident on the reflecting section and an optical path from when the first light is specularly reflected by the reflecting section and when the first light is emitted from the light source to when the first light is incident on the reflecting section and when the first light is specularly reflected by the reflecting section and when the first light is specularly reflected by the reflecting section and when the second ... the Effect of the Invention

[0006] According to the present invention, it is possible to provide an optical system, a light source device, and an image display device that can be configured compactly. [Brief description of the drawings]

[0007] [Figure 1] 2 is a schematic configuration diagram showing an optical path of blue laser light in a light source device according to an embodiment of the present invention. FIG. [Diagram 2] 2 is a schematic diagram showing the optical path of fluorescent light in the light source device according to the embodiment; FIG. [Diagram 3] FIG. 2 is an explanatory diagram of the arrangement of dichroic mirrors according to the embodiment. [Figure 4] 3A and 3B are explanatory diagrams illustrating a configuration of a phosphor unit included in the light source device according to the embodiment. [Diagram 5] 5A to 5C are explanatory diagrams of a fixing method of a dichroic mirror according to the embodiment. [Figure 6] 13A and 13B are explanatory diagrams of a modified example of a fixing method of the dichroic mirror according to the embodiment. [Figure 7] 3 is an explanatory diagram of a dichroic mirror according to the embodiment. FIG. [Figure 8] 13A to 13C are explanatory diagrams of a modified example of a fixing method according to the embodiment. [Figure 9] 13A to 13C are explanatory diagrams of a modified example of a fixing method according to the embodiment. [Figure 10] 13A to 13C are explanatory diagrams of a modified example of a fixing method according to the embodiment. [Figure 11] 13A to 13C are explanatory diagrams of a modified example of a fixing method according to the embodiment. [Figure 12] 13A to 13C are explanatory diagrams of a modified example of a fixing method according to the embodiment. [Figure 13] 1 is a schematic diagram showing a configuration of a projector device including a light source device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] FIG. 1 is a schematic diagram showing the optical path of blue laser light in a light source device 20 according to an embodiment of the present invention.

[0009] As shown in FIG. 1, the light source device 20 has, arranged in order in the direction of light propagation, a laser light source (excitation light source) 21, a coupling lens 22, a first optical system 23, a dichroic mirror 24 (an example of an optical element), a second optical system 25 (an example of a light-guiding optical system), a phosphor unit 26, an example of a wavelength conversion unit, a refractive optical system 27, and a light tunnel 29, an example of a light mixing element.

[0010] The laser light source 21 is, for example, an array of light sources that emit a plurality of laser beams. The laser light source 21 emits, for example, light in the blue band (blue laser light) with a center of emission intensity of 455 [nm]. Hereinafter, the blue laser light will be simply referred to as blue light. The blue light emitted from the laser light source 21 is linearly polarized light with a constant polarization direction, and is also used as excitation light for exciting a phosphor in the phosphor unit 26 described later.

[0011] The light emitted from the laser light source 21 may be light of a wavelength capable of exciting a phosphor described later, and is not limited to light in the blue wavelength band. The laser light source 21 has a plurality of light sources, but is not limited to this, and may be configured with a single light source. The laser light source 21 can be configured with a plurality of light sources arranged in an array on a substrate, but is not limited to this, and may be configured in other ways.

[0012] The coupling lens 22 is a lens that receives the blue light emitted from the laser light source 21 and converts it into parallel light (collimated light). In the following, the concept of parallel light is not limited to completely collimated light, but includes approximately collimated 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 an increase or decrease in the number of light sources of the laser light source 21.

[0013] In the light source device 20 according to this embodiment, the laser light source 21 and the coupling lens 22 constitute a light source unit. For example, the laser light source 21 is composed of a plurality of laser diodes arranged in rows and columns. That is, the light source unit is composed of these laser diodes and the coupling lens 22 arranged on the emission surface side of the laser diodes.

[0014] The first optical system 23 has positive power as a whole, and includes, in this order from the laser light source 21 side to the phosphor unit 26 side, a large-diameter lens 23a and a negative lens 23b. The large-diameter lens 23a constitutes an example of a large-diameter element, has positive power, and is composed of a lens that collects and combines the parallel light emitted from the coupling lens 22. The negative lens 23b constitutes an example of a collimating element, and is composed of a lens that converts the blue light collected by the large-diameter lens 23a into parallel light. The first optical system 23 reduces the diameter of the blue light (excitation light) that has become approximately parallel light from the coupling lens 22 and enters it, and guides it to the dichroic mirror 24.

[0015] The dichroic mirror 24 is disposed at an incline with respect to the propagation direction of the blue light emitted from the first optical system 23. More specifically, the dichroic mirror 24 is disposed with its front end inclined downward along the propagation direction of the blue light emitted from the first optical system 23. The dichroic mirror 24 has an optical property of reflecting the blue light that has been made substantially parallel by the first optical system 23, while transmitting the fluorescent light (an example of the second color light, the second light) converted by the phosphor unit 26. For example, the dichroic mirror 24 is coated with a coating that has the above-mentioned optical property.

[0016] The dichroic mirror 24 has a length shorter than the width of the first optical system 23. Since the dichroic mirror 24 is configured to have a short dimension, the light source device 20 can be made compact.

[0017] The refractive optical system 27 is composed of a lens that collects the light (blue light and fluorescent light) emitted from the second optical system 25. The light (blue light and fluorescent light) emitted from the phosphor unit 26 passes through and is transmitted by the dichroic mirror 24, and then is collected (refracted) by the refractive optical system 27 and enters the light tunnel 29.

[0018] The optical path of blue light in light source device 20 having such a configuration (hereinafter referred to as "blue light optical path" where appropriate) will be described. The blue light optical path refers to the optical path along which light reflected by the reflecting portion of phosphor unit 26 travels, out of the excitation light emitted by laser light source 21.

[0019] The blue light emitted from the laser light source 21 is converted into a parallel light by the coupling lens 22. The blue light emitted from the coupling lens 22 is collected and combined by the large-diameter lens 23a of the first optical system 23, and then converted into a parallel light by the negative lens 23b. The blue light emitted from the negative lens 23b is reflected by the dichroic mirror 24 and travels toward the second optical system 25. The dichroic mirror 24 forms a reflecting surface 24a that reflects the blue light emitted from the laser light source 21. A point P at the center of the projection image of the excitation light described above is formed on the dichroic mirror 24.

[0020] As described above, the dichroic mirror 24 is disposed shifted toward the first optical system 23 with respect to the optical axis of the second optical system 25. Therefore, the blue light optical path is incident on a part of the second optical system 25 (more specifically, the positive lens 25A) on the first optical system 23 side. The blue light then travels toward 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 phosphor unit 26.

[0021] Here, the blue light incident on the phosphor unit 26 is incident on the reflecting portion. The blue light incident on the reflecting portion is specularly reflected. The blue light specularly reflected by the reflecting portion is incident on a part of the second optical system 25 (more specifically, positive lens 25B) on the opposite side to the first optical system 23. The blue light then travels away from the second optical system 25 at an angle to the optical axis of the second optical system 25, and exits from the second optical system 25 (more specifically, positive lens 25A).

[0022] The blue light emitted from the second optical system 25 (more specifically, the positive lens 25A) does not intersect with the dichroic mirror 24. The blue light beam specularly reflected from the phosphor unit 26 constitutes the excitation light beam emitted from the phosphor unit 26. Because the blue light beam does not intersect with the dichroic mirror 24, a decrease in light utilization efficiency can be suppressed.

[0023] Here, one end 33b (an example of a first end) of the dichroic mirror 24 is the end farther from the blue light emitted from the second optical system 25, and the other end 33a (an example of a second end) of the dichroic mirror 24 is the end closer to the luminous flux of blue light emitted from the second optical system 25.

[0024] The blue light that passes through dichroic mirror 24 without intersecting with it enters refractive optical system 27. The blue light then travels toward refractive optical system 27 at an angle to the optical axis thereof, and enters light tunnel 29. After being reflected multiple times and homogenized inside light tunnel 29, the light enters an illumination optical system disposed outside light source device 20.

[0025] FIG. 2 is a schematic diagram showing the optical path of fluorescent light in the light source device 20 according to this embodiment.

[0026] The optical path of the fluorescent light in light source device 20 (hereinafter referred to as the "fluorescent light path" as appropriate) will be described. Note that, for convenience of explanation, part of the optical path of the fluorescent light is omitted in Fig. 2. The fluorescent light path refers to the optical path along which light that is wavelength-converted by the wavelength conversion section of phosphor unit 26, out of the excitation light emitted by laser light source 21, travels.

[0027] The fluorescent light path is the same as the above-mentioned blue light path until the blue light emitted from the laser light source 21 is guided to the phosphor unit 26. Here, the blue light incident on the phosphor unit 26 is assumed to be incident on a wavelength conversion section. The blue light incident on the wavelength conversion section acts as excitation light for the phosphor, and is wavelength-converted by the phosphor to become fluorescent light including, for example, a yellow wavelength range, and is Lambert-reflected by the action of the reflective coat and the phosphor layer.

[0028] The fluorescent light that has been Lambert-reflected by the wavelength conversion unit is converted into parallel light by the second optical system 25. The fluorescent light that has exited from the second optical system 25 passes through the dichroic mirror 24 and enters the refractive optical system 27.

[0029] Here, one end 33b of the dichroic mirror 24 is located outside the flux of the fluorescent light, and the other end 33a of the dichroic mirror 24 is located inside the flux of the fluorescent light.

[0030] The fluorescent light then approaches the optical axis of refractive optical system 27 at an angle to enter light tunnel 29. After being reflected multiple times and homogenized inside light tunnel 29, the light enters an illumination optical system located outside light source device 20.

[0031] In this way, in the light source device 20 according to this embodiment, the optical path of the blue light emitted from the laser light source 21 is made different before and after reflection from the phosphor unit 26. More specifically, the blue light optical path is formed so that the point at the center of the projection image of the blue light projected from the laser light source 21 onto the dichroic mirror 24 does not intersect with the light flux of the blue light reflected from the phosphor unit 26. As a result, the light flux of the blue light emitted from the phosphor unit 26 does not intersect with the center of the projection image of the blue light emitted from the laser light source 21, and therefore it is possible to prevent the blue light from passing through the same point on the dichroic mirror 24, and therefore it is possible to suppress a situation in which the dichroic mirror 24 is damaged due to an increase in the light collection density, and it is possible to improve reliability.

[0032] Also, since there is no need to prepare special optical elements such as a retardation plate or a polarization separation element (polarizing beam splitter) to separate the optical path of the blue light emitted from phosphor unit 26, it is possible to reduce the number of parts, reduce manufacturing costs, and miniaturize light source device 20. Furthermore, since no optical components that manipulate polarized light such as a retardation plate or a polarization separation element are used, it is possible to suppress a decrease in light utilization efficiency due to the reflectance, transmittance, absorptance, etc. of the optical components.

[0033] Furthermore, in the light source device 20 according to this embodiment, the blue light emitted from the laser light source 21 is linearly polarized light with a fixed polarization direction. In addition, the light source unit having a plurality of laser light sources 21 is arranged so that the directions of the linear polarization are all the same. Therefore, the directions of the linear polarization of the light emitted from the light source unit are uniform. The direction of the linear polarization can be determined by the direction in which the light source unit is arranged. If the light source unit is tilted according to the inclination of the light tunnel 29, the direction of the linear polarization changes. In such a situation in which the direction of the linear polarization changes, if the configuration is such that the polarization is manipulated by a polarization separation element or the like, the light utilization efficiency may decrease when passing through the polarization separation element. In the light source device 20 according to this embodiment, since the configuration for manipulating the polarization is not adopted, it is possible to prevent the light utilization efficiency from decreasing due to the inclination of the laser light source 21.

[0034] 3 is a diagram for explaining the arrangement of the dichroic mirror 24 according to the present embodiment. FIG. 3 shows the arrangement of the dichroic mirror 24 and the second optical system 25 when viewed from the position of the refractive optical system 27 to the position of the second optical system. 25 1 and 2. blue The light propagates from the back of the paper in FIG. 3 to the front, and is converted into parallel light by the second optical system 25. blue The fluorescent light is emitted as a light beam 71 toward the refractive optical system 27. The dichroic mirror 24 is disposed so as to overlap with the fluorescent light beam 72 emitted from the positive lens 25A of the second optical system 25. The dichroic mirror 24 is disposed so that one end 33b is outside the fluorescent light beam 72. The other end 33 a is disposed in the fluorescent light beam 72 .

[0035] The blue light reflected by phosphor unit 26 enters second optical system 25, and propagates from positive lens 25A as blue light beam 71 from the back side to the front side of the page in FIG. 3 to enter refractive optical system 27. Dichroic mirror 24 is disposed outside blue light beam 71 so as not to overlap with blue light beam 71. Dichroic mirror 24 is disposed on the opposite side of blue light beam 71 with respect to optical axis 25C of second optical system 25.

[0036] Of the fluorescent light beam 72, the fluorescent light that overlaps with the dichroic mirror 24 passes through the dichroic mirror 24, but a portion of the fluorescent light is reflected or absorbed by the dichroic mirror 24, resulting in a weakened intensity. 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 arrangement of the dichroic mirror shown in Fig. 3, the intensity is weak on the side of one end 33b with respect to the optical axis 25C (the left side in Fig. 3), and the intensity is strong on the opposite side of one end 33b with respect to the optical axis 25C (the right side in Fig. 3).

[0037] 3(A) is an example in which the center line 33 in the short side direction of the dichroic mirror 24 overlaps with the optical axis 25C of the second optical system 25. With this arrangement, the intensity distribution of the fluorescent light flux 72 can be made symmetrical with respect to the center line 33 in the short side direction of the dichroic mirror 24, and the intensity distribution of the fluorescent light emerging from the refractive optical system 27 can be made more uniform.

[0038] FIG. 3B shows an example in which the center line of the dichroic mirror 24 in the short side direction is shifted from the optical axis 25C. Since the center of the dichroic mirror 24 is shifted upward in FIG. 3b with respect to the optical axis 25C, the intensity distribution of the fluorescent light beam 72 is stronger on the lower right side in FIG. 3b. In this case, if the orientation of the dichroic mirror 24 is not changed, the optical path of the blue light beam 71 does not change. Therefore, the arrangement of the dichroic mirror 24 in FIG. 3B can adjust the intensity distribution of the fluorescent light beam 72 regardless of the arrangement of the light source 21 and the first optical system 23. This allows the angular distribution of the fluorescent light emitted from the refractive optical system 27 to be adjusted to match the arrangement of the light tunnel 29. In this case, as described above, the distribution of the fluorescent light can be adjusted without being affected by the arrangement of the light source 21 and the first optical system 23.

[0039] Fig. 4 is an explanatory diagram of the configuration of the phosphor unit of the light source device according to this embodiment. In Fig. 4(A), the phosphor unit 26 is shown from the incident direction of blue light, and in Fig. 4(B), the phosphor unit 26 is shown from a direction perpendicular to the incident direction of blue light. Note that the configuration of the phosphor unit 26 shown in Fig. 4 is an example, and is not limited thereto and can be modified as appropriate.

[0040] 4, the phosphor unit 26 has a disk member (substrate) 26A and a drive motor (drive section) 26C that rotates about a rotation axis 26B that passes through the center of the disk member 26A and is perpendicular to the plane of the disk member 26A. The disk member 26A can be, for example, a transparent substrate or a metal substrate (such as an aluminum substrate), but is not limited thereto.

[0041] The phosphor unit 26 (disk member 26A) has a large portion in the circumferential direction (an angle range greater than 270° in the first embodiment) partitioned into a fluorescent region 26D, and a small portion in the circumferential direction (an angle range smaller than 90° in the first embodiment) partitioned into an excitation light reflecting region 26E. The excitation light reflecting region 26E is a first region that reflects (or diffusely reflects) the excitation light reflected by the dichroic mirror 24, and constitutes an example of a reflecting section. The fluorescent region 26D is a region that converts the excitation light reflected by the dichroic mirror 24 and emits fluorescent light, and constitutes an example of a wavelength converting section. The fluorescent region 26D is configured by laminating a reflective coat 26D1, a phosphor layer 26D2, and an anti-reflection coat (AR coat) 26D3 in this order from the lower layer side to the upper layer side.

[0042] The reflective coating 26D1 has a characteristic of reflecting light in the wavelength region of the fluorescent light (emitted light) produced by the phosphor layer 26D2. If the disk member 26A is made of a metal substrate with high reflectivity, the reflective coating 26D1 can be omitted. In other words, the disk member 26A can be given the function of the reflective coating 26D1.

[0043] The phosphor layer 26D2 may be, for example, a phosphor material dispersed in an organic or inorganic binder, a phosphor material crystal formed directly, or a rare earth phosphor such as Ce:YAG. The phosphor layer 26D2 constitutes an example of a wavelength conversion member that converts at least a part of the excitation light into fluorescent light having a wavelength different from that of the excitation light and emits the fluorescent light. The wavelength band of the fluorescent light (emission light) by the phosphor layer 26D2 may be, for example, yellow, blue, green, or red, but in the first embodiment, a case where fluorescent light (emission light) having a yellow wavelength band is used will be described as an example. In addition, although a phosphor is used as the wavelength conversion element in this embodiment, a phosphorescent material, a nonlinear optical crystal, or the like may also be used.

[0044] The anti-reflection coating 26D3 has the property of preventing light reflection on the surface of the phosphor layer 26D2.

[0045] A reflective coat (reflective surface) 26E1 having a characteristic of reflecting light in the wavelength region of blue light guided from the second optical system 25 is laminated on the excitation light reflection region 26E. When the disk member 26A is made of a metal substrate with high reflectivity, the reflective coat 26E1 can be omitted. In other words, the disk member 26A can be given the function of the reflective coat 26E1.

[0046] By rotating disk member 26A by drive motor 26C, the irradiation position of the blue light on phosphor unit 26 moves over time. As a result, a part of the blue light (first color light, an example of first light) incident on phosphor unit 26 is converted into fluorescent light (second color light) having a different wavelength from the blue light (first color light) in fluorescent region (wavelength conversion region) 26D and emitted. Meanwhile, the other part of the blue light incident on phosphor unit 26 is converted into fluorescent light (second color light) having a different wavelength from the blue light (first color light) in fluorescent region (wavelength conversion region) 26D. of portion Encouraged The photoreflection area 26E detects blue light. Reflected as is .

[0047] There is a degree of freedom in the number and range of fluorescent regions 26D and excitation light reflecting regions 26E, and various design modifications are possible. For example, two fluorescent regions and two excitation light reflecting regions may be alternately arranged at 90° intervals in the circumferential direction.

[0048] FIG. 5 is an explanatory diagram of a method for fixing the dichroic mirror 24 according to this embodiment.

[0049] The dichroic mirror 24 has a configuration in which it has an area that is used optically and an area that is not used optically and is used to hold 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 presser 31 that holds the dichroic mirror 24. As for the fixing method, in addition to the configuration shown in the figure, the dichroic mirror 24 may also be directly fixed by adhesive fixing, screws, etc.

[0050] 2, 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 area that is not optically used, that is, an area that does not require any optical function. The mirror holder 30 holds this area that does not require any optical function.

[0051] The other end 33a of the dichroic mirror 24 is located within the flux of the fluorescent light emitted from the second optical system 25, as shown in FIG.

[0052] As shown in FIG. 5(b), an opening 30A is formed in the mirror holder 30, and the fluorescent light flux emitted from the second optical system 25 shown in FIG. 2 passes through the opening 30A.

[0053] Moreover, the blue light emitted from the second optical system 25 shown in FIG. 1 passes through a region of the opening 30A of the mirror holder 30 that does not overlap with the dichroic mirror 24.

[0054] FIG. 6 is an explanatory diagram of a modified example of the method of fixing the dichroic mirror 24 according to the present embodiment.

[0055] In FIG. 5, the mirror holder 30 holds the dichroic mirror 24 so that one end 33b protrudes, but in FIG. 6, the mirror holder 30 holds the dichroic mirror 24 so that one end 33b does not protrude.

[0056] FIG. 7 is an explanatory diagram of the dichroic mirror 24 according to the present embodiment.

[0057] The relationship between the dichroic mirror 24, a first straight line 32 in the X direction that passes through the mirror, and a second straight line 33 in the Y direction that passes through the mirror will be described. The dichroic mirror 24 is made of a transparent substrate, such as glass or sapphire, and has optical functions such as a polarization separation film, a wavelength selective filter function, and a reflective film on its surface. In particular, an optical thin film that transmits or reflects depending on the wavelength is applied to the surface of the dichroic mirror region, which transmits or reflects depending on the wavelength. Two imaginary straight lines (32, 33) are defined on the surface.

[0058] In this example, the second straight line 33 is a straight line extending in the longitudinal direction of the dichroic mirror 24, and the first straight line 32 is a straight line extending in the lateral direction of the dichroic mirror 24, and they are perpendicular to each other. Line and the second straight line 33 is the center line of the dichroic mirror 24 in the short side direction.

[0059] Imaginary line with 2 32,33 The edge of the optical element is each exists, each The ends are 33a, 33b, 32a, and 32b. Let's say .

[0060] As described above, the one end 33b 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.

[0061] The other end 33 a is located within the flux of the fluorescent light emitted from the second optical system 25 and is not held by the mirror holder 30 as described above.

[0062] Furthermore, the one end 32b and the other end 32a are also located within the light flux of the fluorescent light emitted from the second optical system 25, as shown in FIGS.

[0063] The dichroic mirror 24 may be disposed so that the position where the blue light emitted from the laser light source 21 is incident on the reflecting surface 24a of the dichroic mirror 24 is the center in the direction of the imaginary first straight line 32. The other end 33a of the dichroic mirror 24 is located in the fluorescent light beam and in the blue light beam. Therefore, the temperature of the reflecting surface 24a side of the dichroic mirror 24 increases when the fluorescent light and the blue light are irradiated. The dichroic mirror 24 is distorted due to the increase in temperature on one side, and the reflecting surface 24a is curved. Even when the reflecting surface 24a is curved in this way, the change in angle with respect to the blue light beam near the center of the reflecting surface 24a in the direction of the first straight line 32 is smaller than that at the end of the reflecting surface 24a in the direction of the first straight line 32 (near the ends 32a and 32b of the reflecting surface 24a). Therefore, the change in the emission direction of the blue light reflected by the reflecting surface 24a is small even if the temperature of the dichroic mirror 24 increases. As a result, the optical system of this embodiment can stabilize the emission direction of the blue light beam.

[0064] In order to position the center of the blue light flux at the center in the direction of first straight line 32 of dichroic mirror 24, first optical system 23 and the dichroic mirror may be disposed so that the optical axis of first optical system 23 intersects with reflecting surface 24a at the center in the direction of virtual line 32 of dichroic mirror 24. To explain this using the modified example of Fig. 6, the intersection of first straight line 32 and second straight line 33 of dichroic mirror 24 intersects with the optical axis of the first optical system.

[0065] Although the imaginary first straight line 32 and the imaginary second straight line 33 are defined to form an angle of approximately 90 degrees with each other, this is not limited thereto.

[0066] Although the optical elements have been described as rectangular, they may be square, polygonal, circular or elliptical. The optical elements may be designed to have a shape suitable for the unit composition.

[0067] FIG. 8 is an explanatory diagram of a modified example of the fixing method of the dichroic mirror 24 according to the present embodiment. The dichroic mirror 24 is sandwiched between the mirror holder 30 and the mirror retainer 31, and is fixed by fastening the mirror retainer 31 to the mirror holder 30 with a screw 35. The mirror holder 30 is provided with a recess 34c that matches the shape of the dichroic mirror 24. The bottom surface of the recess 34c abuts against the reflecting surface 24a of the dichroic mirror 24 to determine the angle of the reflecting surface 24a. The recess 34c is provided with walls in three directions except for the opposite side to the one end 33b side of the dichroic mirror. These walls of the recess 34c fit with the side of the dichroic mirror 24. Furthermore, the bottom surface of the recess 34c is provided with a protrusion 34a, and a hole 34b is provided in the dichroic mirror 24. The protrusion 34a and the hole 34b fit with each other to determine the position of the dichroic mirror 24 in a direction parallel to the reflecting surface 24a. Here, the recess 34c, the hole 34b, and the protrusion 34a are an example of a positioning portion that determines the position of the dichroic mirror 24 relative to the position of the mirror holder 30. These positioning portions prevent horizontal positional deviation even when the optical system is subjected to shock or vibration, so that the blue light flux and the dichroic mirror do not interfere with each other, and the amount of blue light emitted by the optical system can be stabilized.

[0068] 9 is an explanatory diagram of another modified example of the method of fixing the dichroic mirror 24 according to this embodiment. The dichroic mirror 24 is positioned and fixed by fitting into the recess 34c as in FIG. 8 and being sandwiched between the mirror holder 30 and the mirror retainer 31. A protrusion 34d is provided on the side of the recess of the mirror holder 30, and a notch 34e is provided on the side of the dichroic mirror 24. The notch 34e fits into the protrusion 34d, thereby allowing the positions of the dichroic mirror 24 and the mirror holder 30 to be determined.

[0069] FIG. 10 is a diagram for explaining a modification in which a biasing member is added to the embodiment of FIG. 9. The dichroic mirror 24 of the modification of FIG. 10 is provided with a notch 34h as in the modification of FIG. 9. The notch 34h is V-shaped when viewed from a direction perpendicular to the reflecting surface 24a of the dichroic mirror. The mirror holder 30 is provided with a biasing member 34f. The biasing member 34f is provided with a protrusion 34g that fits into the notch 34h. The biasing member 34f biases the dichroic mirror 24 to press against the wall 34i, which is an example of the reference surface of the mirror holder 30, by a biasing means such as a leaf spring (not shown). Here, the shape of the protrusion 34g is semicircular, and the arc of the protrusion 34g is made to abut against two surfaces of the V-shape of the notch 34h at two points. 9, the dichroic mirror 24 is fixed by being sandwiched between the mirror holder 30 and the mirror retainer 31. By providing the biasing member 34f in this manner, the position of the dichroic mirror 24 can be kept normal even if the external shape of the dichroic mirror 24 fluctuates due to temperature change.

[0070] FIG. 11 is an explanatory diagram of another modified example of the fixing method of the dichroic mirror 24 according to the present embodiment. As in the modified example of FIG. 8, the dichroic mirror 24 is fixed by fitting into the recess 34c and being sandwiched between the mirror holder 30 and the mirror retainer 31. In the modified example of FIG. 11, the end faces 34j and 34k of the dichroic mirror 24 abut against the walls 34i and 34m of the recess. The end 34k is not parallel to the end 34j, and the wall 34m is not parallel to the wall 34i. After the dichroic mirror 24 is arranged so as to fit into the recess 34c, one end 33b of the dichroic mirror 24 is urged in the direction indicated by the arrow 34n by an urging means (not shown). End faces 34j and 34k are tapered, and wall portions 34i and 34m are tapered, so that the dichroic mirror 24 is biased to determine its position in a direction parallel to the reflecting surface 24a. Since the dichroic mirror 24 is constantly biased, even if it temporarily shifts in position due to vibration or impact, it is repositioned by the bias, so that it can maintain a stable position for a long period of time. In addition, the dichroic mirror 24 in FIG. 11 does not require the processing of specially shaped notches or holes, so the dichroic mirror can be easily manufactured.

[0071] FIG. 12 shows another modified example of the method for fixing the dichroic mirror 24 according to this embodiment. It shows 12, dichroic mirror 24 is fixed by being sandwiched between mirror holder 30 and mirror retainer 31, similar to the fixing method shown in Fig. 10, but differs in that heat transfer members 36 are provided between dichroic mirror 24 and mirror holder 30, and between dichroic mirror 24 and mirror retainer 31, as shown in Fig. 12B. Heat Transfer Materials The heat transfer members 36 are disposed above and below the dichroic mirror 24 so as to be in close contact with the dichroic mirror 24, and are sandwiched together with the dichroic mirror 24 by the mirror holder 30 and the mirror retainer 31. The heat transfer members 36 disposed between the mirror holder 30 and the dichroic mirror 24 are in thermal contact with both the dichroic mirror 24 and the mirror holder 30 by being in close contact with them. Similarly, the heat transfer members 36 disposed between the mirror retainer 31 and the dichroic mirror 2436 The dichroic mirror 24 is in close thermal contact with the dichroic mirror 24 and the mirror holder 31. The dichroic mirror 24 is heated by the incident blue light and fluorescent light, and the temperature of the dichroic mirror 24 rises. In particular, the fluorescent light emitted from the phosphor unit 26 is red outside line of Since the dichroic mirror 24 contains blue light and fluorescent light, it is easy to heat the dichroic mirror 24. Therefore, the light incident surface of the dichroic mirror 24 is heated by the incident blue light and fluorescent light, and the temperature rises. When the temperature of the dichroic mirror 24 rises, the dichroic mirror 24 is deformed due to thermal expansion of the material of the substrate and 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 warps or distorts due to stress caused by the thermal expansion of that side. Dichroic mirror 24 If the dichroic mirror 24 is distorted, the angle of the reflecting surface 24a changes, and the direction in which the incident blue light is reflected also changes. 30 The position of the dichroic mirror 24 relative to the light source 22 will fluctuate, resulting in a problem of misalignment.

[0072] 12, the heat transfer member 36 is disposed between the dichroic mirror 24 and the mirror holder 30 and mirror retainer 31, so that the heat of the dichroic mirror 24 can be efficiently transferred to the mirror holder 30 and the mirror retainer 31, thereby reducing the temperature rise of the dichroic mirror 24. This makes it possible to reduce the positional deviation and deformation of the dichroic mirror 24.

[0073] The material of the heat transfer member 36 is preferably a material that has high thermal conductivity and high adhesion to the dichroic mirror 24 and the mirror holder 30. For example, it is preferable to use a metal with relatively low rigidity such as aluminum, tin, solder, etc., a film-like resin with high thermal conductivity, or a rubber material with high thermal conductivity.

[0074] The heat transfer member 36 may be disposed on either side or both sides of the dichroic mirror 24. When the heat transfer member 36 is disposed on both sides, the heat of the dichroic mirror 24 can be efficiently 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 holder 31, the heat of the dichroic mirror 24 is efficiently transferred to the mirror holder 31. 30 In this case, the temperature rise of the mirror holder 30 is suppressed because the heat is hardly transferred to the mirror holder 30 side. 30 The deformation of Since the position of the dichroic mirror 24 can be suppressed, the position of the dichroic mirror 24 is stable.

[0075] 12 may be a heat dissipation member. The mirror retainer 31 or the mirror holder 30 may be provided with fins for heat dissipation, or may be provided with a fan for air cooling or a flow path for cooling water.

[0076] FIG. 13 is a schematic configuration diagram showing a projector device (image projection device) 1 including a light source device 20 according to the first embodiment.

[0077] The projector device 1 has 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 houses 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.

[0078] The illumination optical system 130 substantially uniformly illuminates the image forming element 40 with light homogenized by the light tunnel 29 of the light source device 20. The illumination optical system 130 has, for example, one or more lenses and one or more reflective surfaces.

[0079] The image forming element 40 forms an image by modulating the light illuminated by the illumination optical system 130 (light from the light source optical system of the light source device 20). 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 micromirror surface in synchronization with the light (blue light, green light, red light, yellow light) irradiated from the illumination optical system 130 to generate a color image.

[0080] 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 has, for example, one or more lenses. The cooling device 60 cools each element and device in the projector device 1 that generates heat.

[0081] ●Summary● As described above, the optical systems 24, 25, and 26 according to an embodiment of the present invention are optical systems including a dichroic mirror 24 (an example of an optical member) that reflects blue light (an example of a first light) emitted from a light source, and a fluorescent region 26D (an example of a wavelength conversion section) of a phosphor unit 26 that receives the blue light reflected by the dichroic mirror 24, converts at least a part of the blue light into fluorescent light (an example of a second light) having a wavelength different from that of the blue light, and emits the fluorescent light. The dichroic mirror 24 has an optical characteristic of transmitting the fluorescent light, and includes one end 33b (an example of a first end) located outside the light flux of the fluorescent light, and the other end 33a (an example of a second end) located inside the light flux of the fluorescent light. A mirror holder 30 (an example of a holding member) that holds the dichroic mirror 24 outside the light flux of the fluorescent light is provided. As an example, the mirror holder 30 holds the dichroic mirror 24 at one end 33b.

[0082] This allows the optical system to be configured more compactly than when both ends of the dichroic mirror 24 are held outside the fluorescent light beam.

[0083] The other end 33a is located on the opposite side to the one end 33b, whereby the optical system can be configured compactly in the direction connecting the other end 33a and the one end 33b.

[0084] The second end located within the fluorescent light flux includes not only the other end 33a located opposite the one end 33b, but also one end 32b and the other end 32a located on a straight line 32 perpendicular to the straight line 33 connecting the one end 33b and the other end 33a. This allows the optical system to be configured compactly in the directions of the straight line 33 and the straight line 32.

[0085] The center position of the blue light incident on dichroic mirror 24 is the midpoint between one end 32b and the other end 32a. As a result, even if the temperature of dichroic mirror 24 rises, the change in the emission direction of the blue light reflected by reflective surface 24a becomes small, and the emission direction of the blue light beam can be stabilized.

[0086] The dichroic mirror 24 is not held at the other end 33a, which prevents a decrease in the quality of the fluorescent light caused by providing a holding member at the other end 33a.

[0087] The dichroic mirror 24 is not supported at a portion located within the flux of fluorescent light, thereby preventing a decrease in the quality of the fluorescent light due to the provision of a support member.

[0088] The holding structure for one end 33b of the dichroic mirror 24, which does not require any optical function, is preferably held by adhesion or clamping.

[0089] It is preferable to provide a structure for protecting one end 33b of the dichroic mirror 24 that does not require any optical function and the optically functional portion of the dichroic mirror 24.

[0090] The phosphor unit 26 has an excitation light reflecting region 26E (an example of a reflecting section) 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.

[0091] This prevents the dichroic mirror 24 from degrading the quality of the blue light reflected by the excitation light reflection region 26E.

[0092] The dichroic mirror 24 is not held at the other end 33a, which is the end closer to the blue light flux reflected by the excitation light reflecting region 26E. This allows the optical system to be configured more compactly than when the dichroic mirror 24 is held at the other end 33a, which is the end closer to the blue light flux reflected by the excitation light reflecting region 26E.

[0093] The dichroic mirror 24 and the mirror holder 30 may have a hole 34a and a protrusion 34b that are positioning parts that determine their relative positions. With this, the hole 34b of the dichroic mirror and the protrusion 34a of the mirror holder fit together, stabilizing the position of the dichroic mirror 24 and preventing a decrease in the quality of the blue light reflected by the dichroic mirror 24.

[0094] The dichroic mirror 24 may have a notch 34e as a positioning portion, and the mirror holder 30 may have a protrusion 34d that fits into the notch 34e. This makes it possible to prevent the dichroic mirror 24 from being misaligned with respect to the mirror holder 30, and to prevent a decrease in the quality of the blue light reflected by the dichroic mirror 24.

[0095] The mirror holder 30 may include a biasing member 34f that biases the dichroic mirror 24. As a result, the dichroic mirror 24 is biased so as to abut against the reference surface 34i of the mirror holder 30, so that the position of the dichroic mirror 24 can be stabilized and degradation of the quality of the blue light can be prevented.

[0096] The mirror holder 30 has a heat transfer member 36 between it and the dichroic mirror 24. Alternatively, the mirror holder 30 includes a heat dissipation member that dissipates heat from the dichroic mirror 24. This can reduce positional deviation and deformation of the dichroic mirror 24.

[0097] Between dichroic mirror 24 and fluorescent region 26D, second optical system 25 (an example of a light guiding optical system) is provided which guides the blue light reflected by dichroic mirror 24 to fluorescent region 26D, and second optical system 25 converts the fluorescent light incident from fluorescent region 26D into parallel light and emits it, and the optical axis of second optical system 25 is midway between one end 32b and the other end 32a of dichroic mirror 24. This makes it possible to make the intensity distribution of fluorescent light flux 72 symmetrical with respect to center line 33 in the short side direction of dichroic mirror 24.

[0098] Between dichroic mirror 24 and fluorescent region 26D, second optical system 25 is provided which guides the blue light reflected by dichroic mirror 24 to fluorescent region 26D, and second optical system 25 converts the fluorescent light incident from fluorescent region 26D into parallel light and emits it, and the optical axis of second optical system 25 is shifted from the midpoint between one end 32b and the other end 32a of dichroic mirror 24. This makes it possible to adjust the intensity distribution of luminous flux 72 of fluorescent light regardless of the arrangement of light source 21 and first optical system 23.

[0099] 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.

[0100] The projector device 1 (an example of an image projection device) can be configured compactly by including a light source device 20, an illumination optical system 130 that guides light emitted from the light source device 20 to an image display element, and a projection optical system 50 that projects an image generated by the image display element 40 using the light guided by the illumination optical system 130. [Explanation of symbols]

[0101] 1: Projector device 10: Housing 20:Light source device 21: Laser light source 22: Coupling lens 23: First optical system 23a: Large aperture lens 23b: Negative lens 24: Dichroic mirror (an example of an optical component) 25: Second optical system (light guiding optical system) 25A, 25B: Positive lens 26: Phosphor unit 26D: Fluorescent region (an example of a wavelength conversion section) 26E: Excitation light reflection area (an example of a reflection part) 27: Refractive optical system 29: Light Tunnel 30: Mirror holder (an example of a holding member) 31: Mirror presser 32: The first line in the X direction that passes through the mirror 33: A second line in the Y direction that passes through the mirror 33a: The other end (second end) 33b: One end (first end) 34a, 34d: protrusions (examples of positioning parts) 34b: Hole (an example of a positioning part) 34c: Recess 34e, 34g: Protrusions (examples of positioning parts) 34f: biasing member 36 Heat transfer materials 40: Image forming element 50: Projection optical system 60: Cooling device 130: Illumination optical system [Prior art documents] [Patent documents]

[0102] [Patent Document 1] Patent No. 4711156 [Patent Document 2] Patent No. 5817109

Claims

1. an optical member that reflects a first light emitted from the light source; a wavelength conversion unit that receives the first light reflected by the optical member, converts at least a part of the first light into a second light having a wavelength different from that of the first light, and outputs the second light; a light guiding optical system between the optical member and the wavelength converting unit, the light guiding optical system guiding the first light reflected by the optical member to the wavelength converting unit; A holding member for holding the optical member; An optical system comprising: The first light emitted from the light source is reflected by the optical member to enter the light-guiding optical system from the light source side with respect to the optical axis of the light-guiding optical system, passes through the light-guiding optical system at an angle approaching the optical axis of the light-guiding optical system, and enters the wavelength conversion unit, Of the first light emitted from the light-guiding optical system and incident on the wavelength conversion unit, the first light incident on a reflecting portion in the wavelength conversion unit is specularly reflected by the reflecting portion, enters a part of the light-guiding optical system from the side opposite to the light source side with respect to the optical axis of the light-guiding optical system, passes through the light-guiding optical system at an angle away from the optical axis of the light-guiding optical system, and does not intersect with the optical member after being emitted from the light-guiding optical system, an optical path of the first light from being emitted from the light source to being incident on the reflecting unit and an optical path of the first light after being specularly reflected by the reflecting unit and being emitted from the light-guiding optical system do not intersect with each other, the optical member has an optical property of transmitting the second light, when one end of the optical member in a longitudinal direction is defined as a first end, the other end of the optical member in the longitudinal direction is defined as a second end, one end of the optical member in a lateral direction is defined as a third end, and the other end of the optical member in the lateral direction is defined as a fourth end, the optical member is held by the holding member only at the first end, the holding member is not present on an optical path of the second light, An optical system, wherein the first end is an end located on the light source side, and the second end is an end located on the optical axis side of the light guiding optical system.

2. The optical system described in claim 1, characterized in that the central position of the first light incident on the optical element is at the midpoint between the third end and the fourth end.

3. The optical member has a reflective surface that reflects the first light, 3. The optical system according to claim 1, wherein the optical member has a positioning portion that determines a position of the optical member relative to the holding member in a direction parallel to the reflecting surface.

4. The optical system described in claim 3, characterized in that the holding member has a biasing member that biases the optical element in a direction parallel to the reflecting surface.

5. An optical system described in any one of claims 1 to 4, characterized in that the holding member has a heat transfer member between the optical member and the holding member.

6. An optical system described in any one of claims 1 to 4, characterized in that the holding member is provided with a heat dissipation member that dissipates heat from the optical member.

7. An optical system described in any one of claims 1 to 6, characterized in that the light-guiding optical system converts the second light incident from the wavelength conversion unit into parallel light and emits it, and the optical axis of the light-guiding optical system is midway between the third end and the fourth end of the optical element.

8. An optical system described in any one of claims 1 to 6, characterized in that the light-guiding optical system converts the second light incident from the wavelength conversion unit into parallel light and emits it, and the optical axis of the light-guiding optical system is shifted from the midpoint between the third end and the fourth end of the optical element.

9. A light source device comprising the light source and an optical system described in any one of claims 1 to 8.

10. A light source device according to claim 9, an illumination optical system that guides light emitted from the light source device to an image display element; a projection optical system that projects an image generated by the image display element using the light guided by the illumination optical system.

Images