JP2012063488A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device which can obtain light having uniformed in-plane light intensity distribution in a predetermined minute superposition area, and which can emit light having higher brightness even when it has a fluorescent layer or the like.SOLUTION: A light source device 10 includes: a plurality of solid light sources 24; a plurality of collimator lenses 32; and an integrator optical system 40 which includes a first microlens array 50 having a plurality of first microlenses 51, a second microlens array 60 having a plurality of second microlenses 61, and a superposing optical system 70 allowing a plurality of partial light beams to be superposed on a predetermined minute superposition area. In the light source device 10, the first microlens array 50 and the second microlens array 60 respectively have a first refractive power reduction layer 58 and a second refractive power reduction layer 68 which are provided to be in contact with convex surfaces of the microlenses 51 and 61, respectively, and which have respective intermediate refractive indices between refractive indices of the microlenses 51 and 61 and a refractive index of the air.

Description

  The present invention relates to a light source device and a projector.

Conventionally, a plurality of collimator lenses provided corresponding to each of a plurality of solid light sources and a plurality of solid light sources, each of which substantially parallelizes the light generated by the plurality of solid light sources, and the plurality of collimator lenses A first microlens array having a plurality of first microlenses greater than the number, a second microlens array having a plurality of second microlenses corresponding to the plurality of first microlenses, and a plurality of second microlens arrays. There is known a light source device that includes an integrator optical system having a superimposing optical system that superimposes the partial light flux on a predetermined superimposing region, and makes light incident on a light modulation device arranged in the predetermined superimposing region. A projector including such a light source device is known (see, for example, Patent Document 1).
According to the conventional light source device, since a plurality of solid light sources are provided, it is possible to emit high-luminance light. In addition, according to the conventional light source device, since the integrator optical system described above is provided, as described above, even when a plurality of solid light sources are used to emit high-luminance light, a predetermined overlapping region is used. Thus, it is possible to obtain light with a uniform in-plane light intensity distribution.

JP 2004-220016 A

Therefore, if “light with a uniform in-plane light intensity distribution” is made incident on a fluorescent layer or the like disposed in the light source device, an excessive thermal load may be applied to a part of the light incident region. Disappear. For this reason, it becomes possible to make much light enter into a fluorescent layer etc. As a result, even when it equips with a fluorescent layer etc., it will be considered that it becomes a light source device which can inject | emit light of higher brightness.
Therefore, the inventors of the present invention changed the focal length of each optical element in the conventional light source device (for example, shortened the focal length of the superimposing optical system), and “smaller than the superimposing region in the conventional light source device”. It was considered to arrange a fluorescent layer or the like in the minute overlapping region after light is superimposed on the minute overlapping region.

  However, in the configuration as described above, as shown in a comparative example to be described later, because the "paraxial radius of curvature required in each microlens" becomes too large, it becomes extremely difficult to manufacture the integrator optical system, There is a problem in that it is impossible to obtain light with a uniform in-plane light intensity distribution in a predetermined minute overlap region, and thus it is not possible to emit light with higher brightness when a fluorescent layer or the like is provided. There was found.

  Therefore, the present invention has been made to solve the above-described problems, and can emit light with high luminance, and obtain light with a uniform in-plane light intensity distribution in a predetermined minute overlapping region. An object of the present invention is to provide a light source device that can emit light with higher luminance even when a fluorescent layer or the like is provided. It is another object of the present invention to provide a projector that includes such a light source device and that can project a projected image with high luminance and little brightness unevenness.

[1] A light source device of the present invention is provided corresponding to each of a plurality of solid light sources and the plurality of solid light sources, and a plurality of collimators that substantially parallelize the light generated by the plurality of solid light sources, respectively. A first microlens array having a lens, a plurality of first microlenses greater than the number of the plurality of collimator lenses, and a second microlens having a plurality of second microlenses corresponding to the plurality of first microlenses. And an integrator optical system having a superimposing optical system that superimposes a plurality of partial light fluxes from the second microlens array on a predetermined minute superimposing region, wherein the first microlens array includes A plurality of plano-convex microlenses as the first microlens, and the plurality of first microlenses A first refractive power reduction layer disposed in contact with the surface and having an intermediate refractive index between the refractive index of the first microlens and the refractive index of air, and the second microlens array includes The second microlens has a plurality of plano-convex microlenses, and is disposed in contact with the convex surface of the plurality of second microlenses, and has an intermediate refractive index between the refractive index of the second microlens and the refractive index of air. It further has the 2nd refractive power reduction layer which has.

  For this reason, according to the light source device of the present invention, since a plurality of solid light sources are provided, it is possible to emit high-luminance light as in the conventional light source device.

  In addition, according to the light source device of the present invention, the first microlens array having a plurality of first microlenses larger than the number of the plurality of collimator lenses, and the plurality of second microlenses corresponding to the plurality of first microlenses. And a superimposing optical system that superimposes a plurality of partial light beams from the second microlens array on a predetermined minute superimposing region, and the first microlens array is a convex surface of the plurality of first microlenses. The first microlens array further includes a first refractive power reduction layer disposed in contact with the first microlens and having an intermediate refractive index between the refractive index of the first microlens and the refractive index of air. The second microlens array includes a plurality of second microlenses. And a second refractive power reduction layer having a refractive index intermediate between the refractive index of the second microlens and the refractive index of air. Since the integrator optical system is provided, the integrator optical system can be manufactured by reducing the “paraxial radius of curvature required for each microlens” by interposing each refractive power reduction layer. It is possible to obtain light with a uniform in-plane light intensity distribution in the overlapping region.

  In addition, according to the light source device of the present invention, since the integrator optical system is provided, an excessive thermal load is not applied to a part of the region where the light is incident, so that a large amount of light is applied to the fluorescent layer or the like. As a result, even when a fluorescent layer or the like is provided, light with higher luminance can be emitted.

  Therefore, the light source device of the present invention can emit high-luminance light, can obtain light with a uniform in-plane light intensity distribution in a predetermined minute overlapping region, and can also emit fluorescence. Even in the case of providing a layer or the like, the light source device can emit light with higher luminance.

  In the present invention, the “microlens array” means a plurality of microlenses arranged along a predetermined plane.

  In the light source device of the present invention, the paraxial radius of curvature of each microlens is preferably 1 mm or less. By adopting such a configuration, it becomes possible to easily manufacture the integrator optical system.

  In the light source device of the present invention, when the curvature coefficient of each microlens is K, the convex surface of each microlens satisfies “−1.1 ≦ K ≦ −0.9” (that is, parabolic surface). Or a parabolic approximate curved surface). With such a configuration, it is possible to emit light with a more uniform in-plane light intensity distribution in a predetermined minute overlapping region.

  In the light source device of the present invention, when the convex surface of the first microlens and the convex surface of the second microlens are arranged to face each other, the first refractive power reduction layer and the second refractive power reduction layer are provided. However, it is also possible to use one refractive power reducing layer (that is, filling between the first microlens array and the second microlens array).

[2] In the light source device of the present invention, the refractive index of the first refractive power reduction layer is na1, the refractive index of the second refractive power reduction layer is na2, and the refractive index of the first microlens is nb1. When the refractive index of the second microlens is nb2, it is preferable that the relationship of “0 <nb1-na1 <0.1” and “0 <nb2-na2 <0.1” is satisfied.

  With such a configuration, it becomes possible to make the integrator optical system easier to manufacture by making the paraxial radius of curvature of each microlens appropriate.

  In the above case, it is more preferable to satisfy the relations “0.001 <nb1-na1 <0.05” and “0.001 <nb2-na2 <0.05”.

[3] In the light source device of the present invention, the solid-state light source is preferably composed of a semiconductor laser.

  Since semiconductor lasers are small and have high output, it is possible to obtain a light source device that is small and has high output by integrating such semiconductor lasers at high density.

[4] In the light source device of the present invention, it is preferable that the minute overlap region has a size included in a square having a side of 1 mm.

  By adopting such a configuration, it is possible to suppress a decrease in light utilization efficiency of the light source device due to a sufficiently small area of the micro-overlapping region that is too wide.

  By the way, depending on the type of object (fluorescent layer, etc.) on which light is superimposed, the superimposed light may spread and spread, and from this point of view, the minute overlapping region is included in a square with a side of 0.8 mm. More preferably, it has a size that is

[5] In the light source device of the present invention, the number of the first microlenses and the second microlenses is preferably 100 times or more the number of the collimator lenses.

  By adopting such a configuration, it becomes possible to divide the light from the collimator lens into a sufficient number of partial light beams, and as a result, the in-plane light intensity distribution is made more uniform at a predetermined overlapping position. Light can be obtained.

  From the above viewpoint, the number of the first microlenses and the second microlenses is more preferably 400 times or more the number of the collimator lenses.

[6] In the light source device of the present invention, the fluorescent layer is located at or near the position where the light from the integrator optical system is superimposed, and generates fluorescence from part or all of the light from the superimposed optical system It is preferable to further comprise.

With this configuration, it is possible to obtain desired color light using a solid light source that generates specific color light.
The above configuration is particularly effective when a lens integrator optical system is arranged at the subsequent stage of the light source device to make the in-plane light intensity distribution uniform.

  In the above case, it is more preferable that the fluorescent layer is located at a position where light from the integrator optical system is superimposed.

  By adopting the above-described configuration, light having a uniform in-plane light intensity distribution is incident on the fluorescent layer in a predetermined minute overlapping region, so that excessive heat is applied to a part of the region where the light is incident. No negative load.

[7] The light source device according to the present invention further includes a transmission type diffusing unit that is positioned at or near the position where the light from the integrator optical system is superimposed and that allows the light from the superimposed optical system to pass through while diffusing. It is preferable to provide.

With such a configuration, the color light from the solid light source that generates the specific color light can be used as it is with high light utilization efficiency in various applications.
The above configuration is also particularly effective when the lens integrator optical system is arranged in the subsequent stage of the light source device to make the in-plane light intensity distribution uniform.

  In the above case, it is more preferable that the transmission type diffusing means is located at a position where light from the integrator optical system is superimposed.

  As the transmissive diffusing means, for example, a microlens diffusing plate, a holographic diffusing plate, polished glass, or the like can be used.

  By adopting the above configuration, light having a uniform in-plane light intensity distribution is incident on the transmission type diffusing unit in a predetermined minute overlapping region. No thermal load is applied.

[8] A projector according to the present invention includes an illumination device including the light source device according to the present invention, a light modulation device that modulates light from the illumination device according to image information, and a projection that projects light from the light modulation device. And an optical system.

  For this reason, the projector of the present invention can emit high-luminance light, and can obtain light with a uniform in-plane light intensity distribution in a predetermined minute overlapping region even when a plurality of solid-state light sources are used. And a light source device capable of emitting light with higher brightness by superimposing light on a micro-overlapping area, and thus capable of projecting a projected image with high brightness and little brightness unevenness It becomes.

FIG. 2 is a plan view showing an optical system of the projector 1000 according to the embodiment. The figure which looked at the solid light source array 20 in embodiment from the collimator lens array 30 side. The graph which shows the emitted light intensity characteristic of the solid light source 24 in embodiment, and the emitted light intensity characteristic of fluorescent substance. The partial expansion perspective view of the 1st micro lens array 50 in an embodiment. The figure shown in order to demonstrate the 1st micro lens array 50 and the 2nd micro lens array 60 in embodiment. The side view of the 1st micro lens 51a in a comparative example. The side view of the 1st micro lens 51b and the 1st refractive power reduction layer 58b in the test example 1. FIG. The side view of the 1st micro lens 51c in the example 2 of a test, and the 1st refractive power reduction layer 58c. The figure which shows the mode of superimposition by the integrator optical system 40d (not shown) in Test Example 3. FIG. FIG. 9 is a partially enlarged perspective view of a first microlens array 53 in Modification 1. The top view which shows the optical system of the light source device 14 which concerns on the modification 2. FIG. The top view which shows the optical system of the light source device 16 which concerns on the modification 3. FIG. The top view which shows the optical system of the light source device 18 which concerns on the modification 4. FIG.

  Hereinafter, a light source device and a projector of the present invention will be described based on the embodiments shown in the drawings.

[Embodiment]
FIG. 1 is a plan view showing an optical system of a projector 1000 according to the embodiment. In FIG. 1, each microlens is enlarged and displayed for easy understanding of the orientation of each microlens. The same applies to FIGS. 11 to 13 described later.
FIG. 2 is a diagram of the solid light source array 20 in the embodiment as viewed from the collimator lens array 30 side.
FIG. 3 is a graph showing the emission intensity characteristics of the solid-state light source 24 and the emission intensity characteristics of the phosphor in the embodiment. FIG. 3A is a graph showing the emission intensity characteristics of the solid-state light source 24, and FIG. 3B is a graph showing the emission intensity characteristics of the phosphor contained in the fluorescent layer 84. The light emission intensity characteristic is a characteristic of how much light is emitted with what intensity when a voltage is applied for a light source and excitation light is incident for a phosphor. Say. The vertical axis of the graph represents relative light emission intensity, and the light emission intensity at the wavelength where the light emission intensity is strongest is 1. The horizontal axis of the graph represents the wavelength.

FIG. 4 is a partially enlarged perspective view of the first microlens array 50 in the embodiment.
FIG. 5 is a diagram for explaining the first microlens array 50 and the second microlens array 60 in the embodiment.
In the drawings describing the optical system and each optical element, three directions orthogonal to each other are the z-axis direction (illumination optical axis 100ax direction in FIG. 1) and the x-axis direction (parallel to the paper surface in FIG. 1 and the z-axis direction). And a y-axis direction (a direction perpendicular to the paper surface in FIG. 1 and a direction perpendicular to the z-axis).

As shown in FIG. 1, the projector 1000 according to the embodiment includes an illumination device 100, a color separation light guide optical system 200, three liquid crystal light modulation devices 400R, 400G, and 400B as light modulation devices, and a cross dichroic prism. 500 and a projection optical system 600.
The illumination device 100 includes a light source device 10 and a lens integrator optical system 110. The lighting device 100 emits light including red light, green light, and blue light as illumination light (that is, light that can be used as white light).

  The light source device 10 includes a solid light source array 20, a collimator lens array 30, an integrator optical system 40, a fluorescence generation unit 80, and a collimator optical system 90.

As shown in FIGS. 1 and 2, the solid light source array 20 has a plurality of solid light sources. Specifically, it has a substrate 22 and 25 solid-state light sources 24 (only one is shown with a symbol). In the solid state light source array 20, as shown in FIG. 2, 25 solid state light sources 24 are arranged in a matrix of 5 rows and 5 columns.
In the light source device of the present invention, the number of solid light sources may be plural (two or more) and is not limited to 25. Further, the plurality of solid light sources may be arranged discretely.

  The substrate 22 has a function of mounting the solid light source 24. Although detailed description is omitted, the substrate 22 has a function of mediating supply of electric power to the solid light source 24, a function of radiating heat generated by the solid light source 24, and the like.

  The solid-state light source 24 is composed of a semiconductor laser that generates blue light that serves as both excitation light and color light (peak of emission intensity: about 460 nm, see FIG. 3A). As shown in FIG. 2, the semiconductor laser has a rectangular light emitting region, and is configured such that the divergence angle along the short side direction of the light emitting region is larger than the divergence angle along the long side direction of the light emitting region. Has been.

As shown in FIG. 1, the collimator lens array 30 is provided corresponding to each of the 25 solid light sources 24, and 25 collimators that substantially parallelize the light generated by the 25 solid light sources 24. It has a meter lens 32 (only one is shown with a symbol). The 25 collimator lenses 32 are arranged in a matrix of 5 rows and 5 columns so as to correspond to the 25 solid light sources 24. The collimator lens 32 is formed of, for example, an aspherical plano-convex lens having a hyperboloidal entrance surface and a flat exit surface.
In the light source device of the present invention, the number of collimator lenses is not limited to 25 as long as it corresponds to the number of solid light sources. Each collimator lens may be arranged discretely.
The collimator lens 32 collimates the light from the solid light source 24 so as to be within a range of 5.46 mm × 5.46 mm.

  The integrator optical system 40 includes a first microlens array 50, a second microlens array 60, and a superimposing optical system 70. The first microlens array 50 and the second microlens array 60 are connected by a connecting portion 41 made of white plate glass (B270).

As shown in FIGS. 1 and 5, the first microlens array 50 includes a plurality of microlenses 51 and a first refractive power reduction layer 58.
The number of the plurality of first microlenses 51 (only one is illustrated) is larger than the number of the plurality of collimator lenses 32. Specifically, the number of the first microlenses 51 is 608400, that is, 24336 (156 × 156) for one collimator lens 32, which means that “the number of the first microlenses is The condition “the number of collimator lenses is 100 times or more” is satisfied.
The first microlens array 50 divides the light from the collimator lens array 30 into a plurality of partial light beams.

As shown in FIG. 4, the plurality of first microlenses 51 are arranged in a so-called lattice arrangement. The pitch of the first microlenses 51 is 35 μm.
The plurality of first microlenses 51 includes a plurality of plano-convex microlenses. The exit surfaces of the plurality of first microlenses 51 are parabolic approximate curved surfaces (elliptical surfaces) of “K1 = −0.99” when the curvature coefficient of the first microlens 51 is K1. This satisfies the condition of “−1.1 ≦ K1 ≦ −0.9”.
Further, the paraxial radius of curvature of the first microlens 51 is 0.16 mm, that is, the condition that the paraxial radius of curvature is 1 mm or less is satisfied.
The plurality of first microlenses 51 are made of white plate glass (B270) where “nb1 = 1.523” when the refractive index of the first microlens 51 is nb1.
The focal length of the first microlens 51 is 3.0 mm.

The first refractive power reduction layer 58 is disposed in contact with the convex surface of the plurality of first microlenses 51 and has a refractive index intermediate between the refractive index of the first microlens 51 and the refractive index of air.
The first refractive power reduction layer 58 is made of optical glass (BK7) that satisfies “na1 = 1.51633” when the refractive index of the first refractive power reduction layer 58 is na1.
Therefore, “nb1-na1 = 0.00667” is satisfied, which satisfies the relationship “0 <nb1-na1 <0.1”.

As shown in FIGS. 1 and 5, the second microlens array 60 has a plurality of microlenses 61 and a second refractive power reduction layer 68.
The multiple second microlenses 61 correspond to the multiple first microlenses 51.
Since the plurality of second microlenses 61 have basically the same configuration as that of the plurality of second microlenses 51, a detailed description of the configuration is omitted. Further, the second refractive power reducing layer 68 has basically the same configuration as the first refractive power reducing layer 58, and therefore a detailed description of the configuration is omitted.

From the above, the second microlens array 60 and the second microlens 61 satisfy the following conditions.
That is, the condition that “the number of second microlenses is 100 times the number of collimator lenses” is satisfied.
Further, when the curvature coefficient of the second microlens 61 is K2, it is a parabolic approximate curved surface (ellipsoid) of “K2 = −0.99”, and “−1.1 ≦ K2 ≦ −0.9”. Satisfy the condition of
The paraxial radius of curvature of the second microlens 61 is 0.16 mm, that is, the condition that the paraxial radius of curvature is 1 mm or less is satisfied.
The plurality of second microlenses 61 are made of white glass (B270) where “nb2 = 1.523” when the refractive index of the second microlens 61 is nb2, and the second refractive power reduction layer 68 is When the refractive index of the second refractive power reduction layer 68 is na2, since it is made of optical glass (BK7) that becomes “na2 = 1.51633”, it becomes “nb2−na2 = 0.00667”. The relationship 0 <nb2-na2 <0.1 is satisfied.

  In the integrator optical system 40 according to the embodiment, the first macro lens array 50 and the second micro lens array 60 are arranged so that the convex surface of the first micro lens 51 and the convex surface of the second micro lens 61 face opposite sides. Has been.

The superimposing optical system 70 superimposes a plurality of partial light beams from the second microlens array 60 on a predetermined minute superimposing region. The superimposing optical system 70 is composed of, for example, an aspherical plano-convex lens having a flat entrance surface and a hyperboloidal exit surface. The focal length of the superimposing optical system 70 is 60 mm.
Although the detailed description by illustration is abbreviate | omitted, the micro superimposition area | region by said integrator optical system 40 is a magnitude | size included by the square of 0.7 mm of one side.

The fluorescence generation unit 80 includes a transparent member 82 and a fluorescence layer 84. The fluorescence generation unit 80 has a square plate shape as a whole, and is fixed at a predetermined position (see FIG. 1).
The transparent member 82 carries the fluorescent layer 84. The transparent member 82 is made of optical glass, for example. On the transparent member, a layer (for example, a dielectric multilayer film) that transmits light from the integrator optical system and reflects fluorescence (described later) may be formed.

The fluorescent layer 84 is located at a position where light from the integrator optical system 40 overlaps, and red light (emission intensity peak: about 610 nm) and green light (emission intensity peak) from a part of the light from the integrator optical system 40. : About 550 nm) is generated (see FIG. 3B).
For this reason, the fluorescence generation unit 80 includes light (that is, light that can be used as white light) including blue light that passes through the fluorescent layer 84 without being involved in generation of fluorescence together with fluorescence (red light and green light). Eject.

The fluorescent layer 84 is made of a layer containing (Y, Gd) ₃ (Al, Ga) ₅ O ₁₂ : Ce, which is a YAG phosphor. In addition, as a fluorescent layer, the fluorescent layer containing other fluorescent substance (YAG type fluorescent substance other than the above, a silicate type fluorescent substance, a TAG type fluorescent substance etc.) can also be used. In addition, as a fluorescent layer, a phosphor that converts light from the condensing optical system into red light (for example, CaAlSiN ₃ red phosphor) and a phosphor that converts light from the condensing optical system into green (for example, β sialon green) A fluorescent layer containing (phosphor) can also be used.
A part of the blue light that passes through the fluorescent layer 84 without being involved in the generation of fluorescence is emitted together with the fluorescence. At this time, since the blue light is scattered or reflected in the fluorescent layer 84, the blue light is emitted from the fluorescence generation unit 80 as light having a distribution characteristic (so-called Lambertian distribution) substantially similar to the fluorescence.

The collimator optical system 90 makes the light from the fluorescence generation unit 80 substantially parallel. As shown in FIG. 1, the collimator optical system 90 includes a first lens 92 and a second lens 94.
The first lens 92 and the second lens 94 are biconvex lenses. Note that the shapes of the first lens and the second lens are not limited to the above shapes, and a collimator optical system including the first lens and the second lens substantially parallelizes the light from the fluorescence generation unit. Any shape can be used. Further, the number of lenses constituting the collimator optical system may be one, or three or more.

The lens integrator optical system 110 includes a first lens array 120, a second lens array 130, a polarization conversion element 140, and a superimposing lens 150.
Note that a rod integrator optical system including an integrator rod can be used instead of the lens integrator optical system.

  As shown in FIG. 1, the first lens array 120 includes a plurality of first small lenses 122 for dividing the light from the light source device 10 into a plurality of partial light beams. The first lens array 120 has a function as a light beam splitting optical element that splits light from the light source device 10 into a plurality of partial light beams, and the plurality of first small lenses 122 are in a plane orthogonal to the illumination optical axis 100ax. It has a configuration arranged in a matrix of multiple rows and multiple columns. Although not illustrated, the outer shape of the first small lens 122 is substantially similar to the outer shape of the image forming regions of the liquid crystal light modulation devices 400R, 400G, and 400B.

  The second lens array 130 has a plurality of second small lenses 132 corresponding to the plurality of first small lenses 122 in the first lens array 120. The second lens array 130 has a function of forming the image of each first small lens 122 together with the superimposing lens 150 in the vicinity of the image forming area of the liquid crystal light modulators 400R, 400G, and 400B. The second lens array 130 has a configuration in which a plurality of second small lenses 132 are arranged in a matrix of a plurality of rows and a plurality of columns in a plane orthogonal to the illumination optical axis 100ax.

The polarization conversion element 140 is a polarization conversion element that emits each partial light beam divided by the first lens array 120 as light composed of substantially one type of linearly polarized light having a uniform polarization direction.
The polarization conversion element 140 transmits one linear polarization component of the polarization components included in the light from the light source device 10 as it is, and reflects the other linear polarization component in a direction perpendicular to the illumination optical axis 100ax. A reflection layer that reflects the other linearly polarized light component reflected by the polarization separation layer in a direction parallel to the illumination optical axis 100ax, and a position that converts the other linearly polarized light component reflected by the reflective layer into one linearly polarized light component. And a phase difference plate.

  The superimposing lens 150 is an optical element that condenses the partial light beams from the polarization conversion element 140 and superimposes them in the vicinity of the image forming regions of the liquid crystal light modulation devices 400R, 400G, and 400B. The superimposing lens 150 is disposed so that the optical axis of the superimposing lens 150 and the illumination optical axis 100ax substantially coincide. The superimposing lens may be composed of a compound lens in which a plurality of lenses are combined.

The color separation light guide optical system 200 includes dichroic mirrors 210 and 220, reflection mirrors 230, 240 and 250, and relay lenses 260 and 270. The color separation light guide optical system 200 separates the light from the illumination device 100 into red light, green light, and blue light, and the liquid crystal light modulation devices 400R and 400G that are to be illuminated with red light, green light, and blue light, respectively. , 400B.
Condensing lenses 300R, 300G, and 300B are disposed between the color separation light guide optical system 200 and the liquid crystal light modulation devices 400R, 400G, and 400B.

In the dichroic mirrors 210 and 220, a wavelength selective transmission film that reflects light in a predetermined wavelength region and passes light in other wavelength regions is formed on the substrate.
The dichroic mirror 210 reflects the red light component and transmits the green light and the blue light component.
The dichroic mirror 220 reflects the green light component and transmits the blue light component.

The red light reflected by the dichroic mirror 210 is reflected by the reflection mirror 230, passes through the condenser lens 300R, and enters the image forming region of the liquid crystal light modulation device 400R for red light.
The green light that has passed through the dichroic mirror 210 together with the blue light is reflected by the dichroic mirror 220, passes through the condenser lens 300G, and enters the image forming area of the liquid crystal light modulation device 400G for green light.
The blue light that has passed through the dichroic mirror 220 passes through the relay lens 260, the incident-side reflection mirror 240, the relay lens 270, the emission-side reflection mirror 250, and the condensing lens 300B. Incident into the area. The relay lenses 260 and 270 and the reflection mirrors 240 and 250 have a function of guiding the blue light component that has passed through the dichroic mirror 220 to the liquid crystal light modulation device 400B.

  The reason why such a relay lens 260, 270 is provided in the optical path of blue light is that the length of the optical path of blue light is longer than the length of the optical path of other color lights, so that light is used due to light divergence or the like. This is to prevent a decrease in efficiency. The projector 1000 according to the embodiment has such a configuration because the length of the optical path of blue light is long, but the length of the optical path of red light is increased so that the relay lens and the reflection mirror are made of red light. A configuration for use in the optical path is also conceivable.

The liquid crystal light modulation devices 400R, 400G, and 400B are light modulation devices that modulate light from the illumination device 100 according to image information, and modulate incident color light according to image information to form a color image. Although not shown, incident-side polarizing plates are interposed between the condenser lenses 300R, 300G, and 300B and the liquid crystal light modulation devices 400R, 400G, and 400B, respectively, so that the liquid crystal light modulation devices 400R, 400G, Between the 400B and the cross dichroic prism 500, an exit side polarizing plate is interposed. The incident-side polarizing plates, the liquid crystal light modulators, and the exit-side polarizing plates modulate the incident color light.
Each liquid crystal light modulation device is a transmission type liquid crystal light modulation device in which a liquid crystal, which is an electro-optical material, is hermetically sealed in a pair of transparent glass substrates. For example, a polysilicon TFT is used as a switching element to convert a given image signal. Accordingly, the polarization direction of one type of linearly polarized light emitted from the incident side polarizing plate is modulated.

  The cross dichroic prism 500 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the emission side polarizing plate. The cross dichroic prism 500 has a substantially square shape in plan view in which four right-angle prisms are bonded together, and a dielectric multilayer film is formed on a substantially X-shaped interface in which the right-angle prisms are bonded together. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, the red light and the blue light are bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized.

  The color image emitted from the cross dichroic prism 500 is projected by the projection optical system 600 and forms an image on the screen SCR.

  Next, effects of the light source device 10 and the projector 1000 according to the embodiment will be described.

  Since the light source device 10 according to the embodiment includes the plurality of solid light sources 24, it is possible to emit high-luminance light as in the conventional light source device.

  Further, according to the light source device 10 according to the embodiment, the first microlens array 50 having the plurality of first microlenses 51 larger than the number of the plurality of collimator lenses 32 corresponds to the plurality of first microlenses 51. A second microlens array 60 having a plurality of second microlenses 61, and a superimposing optical system 70 for superimposing a plurality of partial light beams from the second microlens array 60 on a predetermined minute superimposing region, the first microlens array 50 further includes a first refractive power reduction layer 58 disposed in contact with the convex surface of the plurality of first microlenses 51 and having an intermediate refractive index between the refractive index of the first microlens 51 and the refractive index of air. The second microlens array 60 is disposed in contact with the convex surface of the plurality of second microlenses 61 and is refracted by the second microlens 61 Since the integrator optical system 40 further includes the second refractive power reduction layer 68 having a refractive index intermediate between that of air and the refractive index of air, the “in each microlens 51, 61” is interposed by the refractive power reduction layers 58, 68. By reducing the “required paraxial radius of curvature”, the integrator optical system 40 can be manufactured. As a result, it is possible to obtain light in which the in-plane light intensity distribution is uniform in a predetermined minute overlapping region. Become.

  In addition, according to the light source device 10 according to the embodiment, since the integrator optical system 40 is provided, an excessive thermal load is not applied to a part of the region where the light is incident. As a result, even when a fluorescent layer or the like is provided, it is possible to emit light with higher luminance.

  Due to the above effects, the light source device 10 according to the embodiment can emit light with high luminance, and can obtain light with a uniform in-plane light intensity distribution in a predetermined minute overlapping region. In addition, even when a fluorescent layer or the like is provided, the light source device can emit light with higher luminance.

  Further, according to the light source device 10 according to the embodiment, since the paraxial radius of curvature of each microlens is 1 mm or less, it becomes possible to easily manufacture the integrator optical system.

  Further, according to the light source device 10 according to the embodiment, the convex surface of each microlens satisfies “−1.1 ≦ K ≦ −0.9”, and thus the in-plane light intensity distribution is further increased in a predetermined minute overlapping region. It becomes possible to emit uniform light.

  Further, according to the light source device 10 according to the embodiment, the paraxial radius of curvature of each microlens is satisfied in order to satisfy the relationship of “0 <nb1-na1 <0.1” and “0 <nb2-na2 <0.1”. Therefore, it is possible to make the integrator optical system easier to manufacture.

  In addition, according to the light source device 10 according to the embodiment, the solid light source 24 is made of a semiconductor laser. Therefore, by integrating such semiconductor lasers at a high density, it is possible to obtain a light source device with a small size and a high output. It becomes.

  Further, according to the light source device 10 according to the embodiment, since the minute overlapping region has a size included in a square having a side of 1 mm, the minute overlapping region is too wide with the area of the minute overlapping region being sufficiently small. Accordingly, it is possible to suppress a decrease in light use efficiency of the light source device.

  Further, according to the light source device 10 according to the embodiment, the number of the first microlenses 51 and the second microlenses 61 is 100 times or more the number of the collimator lenses 32, so that the light from the collimator lenses 32 is sufficient. As a result, it is possible to obtain light with a more uniform in-plane light intensity distribution at a predetermined overlapping position.

  Moreover, according to the light source device 10 according to the embodiment, the light source device 10 includes the fluorescent layer 84 that is located at a position where the light from the integrator optical system 40 is superimposed and generates fluorescence from a part of the light from the superimposing optical system 70. It is possible to obtain desired color light by using the solid light source 24 that generates specific color light.

  The projector 1000 according to the embodiment can emit high-luminance light, and can obtain light with a uniform in-plane light intensity distribution in a predetermined overlapping region even when a plurality of solid-state light sources are used. In addition, since the light source device 10 according to the embodiment capable of emitting light with higher luminance by superimposing light on a minute overlapping region is provided, a projected image with high luminance and less unevenness in brightness is projected. It becomes a possible projector.

[Comparative Example, Test Example 1 and Test Example 2]
In Comparative Example, Test Example 1 and Test Example 2, the case where the first microlens does not have the first refractive power reduction layer (Comparative Example) and the case where it has (Test Example 1 and Test Example 2) are compared, When the first refractive power reduction layer was used, a simulation was performed to confirm that the paraxial radius of curvature of the first microlens can be made sufficiently small.

FIG. 6 is a side view of the first microlens 51a in the comparative example.
FIG. 7 is a side view of the first microlens 51b and the first refractive power reduction layer 58b in Test Example 1.
FIG. 8 is a side view of the first microlens 51c and the first refractive power reduction layer 58c in Test Example 2.

  In the following Comparative Examples, Test Example 1 and Test Example 2, simulation was performed assuming that the parts (particularly not described) have the same configuration (parameters) as the light source device 10 according to the embodiment.

  The first microlens array 50a (not shown; made of white plate glass (B270)) in the comparative example does not have the first refractive power reduction layer. In this case, the paraxial radius of curvature required for the first microlens 51a is 11.6 mm. The convex surface of the first microlens 51a was almost flat as shown in FIG.

  The first microlens array 50b (not shown; made of white plate glass (B270)) in Test Example 1 has a first refractive power reduction layer 58b (made of optical glass (BK7)). The first microlens 51b is a planoconvex microlens having a spherical convex surface. In this case, the paraxial radius of curvature required for the first microlens 51b is 0.16 mm. On the convex surface of the first microlens 51b, a clear curved surface was seen as shown in FIG.

The first microlens array 50c (not shown; made of white plate glass (B270)) in Test Example 2 has a first refractive power reducing layer 58c (made of optical glass (BK7)). The first micro lens 51 c is a plano-convex micro lens having a paraboloidal approximate curved surface (ellipsoidal surface) whose convex surface is “K1 = −0.99”. Even in this case, the paraxial radius of curvature required for the first microlens 51c was 0.16 mm. Also on the convex surface of the first microlens 51c, a clear curved surface could be seen as shown in FIG.
The first micro lens 51c in Test Example 2 has the same configuration as the first micro lens 51 in the embodiment.

As a result of the simulation, as shown in FIGS. 6 to 8, when the refractive power reducing layer having an appropriate refractive index is used, the paraxial radius of curvature of the first microlens can be made sufficiently small. It was confirmed that there was.
Note that the comparative example and each test example can be similarly applied to the second microlens.

[Test Example 3]
In Test Example 3, a simulation was performed to confirm that the integrator optical system of the present invention can correctly superimpose a plurality of partial light beams on a predetermined minute superimposition region.

FIG. 9 is a diagram showing a state of superposition by the integrator optical system 40d (not shown) in Test Example 3. In FIG. 9, the closer to white, the higher the intensity of incident light.
In Test Example 3 below, simulation was performed assuming that the parts (particularly not described) have the same configuration (parameters) as those of the light source device 10 according to the embodiment.

  The integrator optical system 40d in Test Example 3 includes a second microlens having the first microlens array 50c in Test Example 2 and a plurality of second microlenses 61c (not shown) corresponding to the first microlens 51c. An array 60c (not shown) and a superimposing optical system 70d (not shown) for superimposing a plurality of partial light beams from the plurality of second microlenses 61c on a predetermined minute superimposing region are provided.

The second microlens array 60c is arranged such that the convex surface of the second microlens 61c faces the opposite side of the convex surface of the first microlens 51c in the first macrolens array 50c, and the first refractive power reduction layer Except for having a second refractive power reducing layer 68c (not shown) instead of 58c, it has the same configuration as the first microlens array 50c.
The second refractive power reduction layer 68c has the same configuration as the first refractive power reduction layer 58c except that the second refractive power reduction layer 68c is disposed in contact with the convex surface of the plurality of second microlenses 61c.

  In the superimposing optical system 70d, the entrance surface is an elliptical surface having a curvature coefficient of -0.917, a paraxial radius of curvature of 31.547 mm, and a thickness along the optical axis of 28 mm, and the exit surface is a flat aspherical plano-convex lens. It was. The superposition optical system 70d is made of optical glass (BK7) having a refractive index of 1.51633. The focal length of the superimposing optical system 70d was 60 mm.

  As a result of the simulation, as shown in FIG. 9, it was confirmed that the integrator optical system 40d described above can correctly superimpose a plurality of partial light beams on a predetermined minute superposition region.

  As mentioned above, although this invention was demonstrated based on said embodiment, this invention is not limited to said embodiment. The present invention can be carried out in various modes without departing from the spirit thereof, and for example, the following modifications are possible.

(1) The dimensions, the number, the material, and the shape of each component described in the above embodiment are exemplifications, and can be changed within a range not impairing the effects of the present invention.

(2) In the above embodiment, each microlens (see FIG. 4) arranged in a so-called lattice arrangement is used. However, the present invention is not limited to this. FIG. 10 is a partially enlarged perspective view of the first microlens array 53 in the first modification. For example, as shown in FIG. 10, each microlens arranged in a so-called staggered arrangement may be used.

(3) In the above embodiment, the first microlens array 50 and the second microlens array 60 connected by the connecting portion 41 are used. However, the present invention is not limited to this. FIG. 11 is a plan view showing an optical system of the light source device 14 according to the second modification. For example, as shown in FIG. 11, a first microlens array and a second microlens array that are not connected by a connecting portion may be used.

(4) In the above embodiment, the integrator optical system 40 is used in which the convex surface of the first microlens 51 and the convex surface of the second microlens 61 face the opposite side. It is not limited. FIG. 12 is a plan view showing an optical system of the light source device 16 according to the third modification. For example, as shown in FIG. 12, an integrator optical system in which the convex surface of the first microlens and the convex surface of the second microlens face each other may be used. In the above case, the first refractive power reduction layer and the second refractive power reduction layer (that is, the space between the first microlens array and the second microlens array is filled). One refractive power reducing layer may be used.

(5) In the above embodiment, the separate second microlens array 60 and the superimposing optical system 70 are used.
However, the present invention is not limited to this. FIG. 13 is a plan view showing an optical system of the light source device 18 according to Modification 4. As shown in FIG. For example, as shown in FIG. 13, when the convex surface of the first microlens and the convex surface of the second microlens are arranged to face each other, and the incident surface of the superimposing optical system is a plane, the superimposing optical system A surface in which the second microlens array is formed on the plane may be used.

(6) In the above embodiment, the light source device 10 that includes the fluorescent layer 84 that generates fluorescence from a part of the light from the condensing optical system and emits light including fluorescence is used. It is not limited. Instead of the fluorescent layer described above, a light source device that includes transmission type diffusing means that allows light from the condensing optical system to pass through while diffusing, and emits light generated by the solid light source as it is may be used. With such a configuration, the color light from the solid light source that generates the specific color light can be used as it is with high light utilization efficiency in various applications.

(7) In the above embodiment, the fluorescence generation unit 80 solid at a predetermined position is used. However, the present invention is not limited to this. You may use the fluorescence production | generation part or the transmissive | pervious diffusion means comprised so that rotation around the predetermined rotating shaft was possible.

(8) In the above embodiment, as the solid light source and the fluorescent layer, the solid light source 24 that generates blue light and the fluorescent layer 84 that generates fluorescence including red light and green light from part of the blue light are used. However, the present invention is not limited to this. For example, as the solid light source and the fluorescent layer, a solid light source that generates violet light or ultraviolet light and a fluorescent layer that generates color light including red light, green light, and blue light from violet light or ultraviolet light may be used.

(9) In the above embodiment, the light source device 10 emits “light that can be used as white light”, but the present invention is not limited to this. A light source device that emits light other than “light that can be used as white light” (for example, light composed of red light and green light, or light including a large amount of specific color light components) may be used.

(10) In the above embodiment, the solid light source 24 that generates blue light having a peak emission intensity of about 460 nm is used. However, the present invention is not limited to this. For example, a solid light source that generates blue light having a light emission intensity peak of 440 nm to 450 nm may be used. With such a configuration, it is possible to improve the fluorescence generation efficiency in the phosphor.

(11) In the above embodiment, the solid light source 24 made of a semiconductor laser is used as the solid light source, but the present invention is not limited to this. For example, you may use the solid light source which consists of a light emitting diode as a solid light source.

(12) Although the transmissive projector is used in the above embodiment, the present invention is not limited to this. For example, a reflective projector may be used. Here, “transmission type” means that a light modulation device as a light modulation means such as a transmission type liquid crystal light modulation device or the like is a type that transmits light, and “reflection type” means This means that the light modulation device as the light modulation means, such as a reflective liquid crystal light modulation device, is a type that reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(13) In the above embodiment, the liquid crystal light modulation device is used as the light modulation device of the projector, but the present invention is not limited to this. In general, the light modulation device only needs to modulate incident light according to image information, and a micromirror light modulation device or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

(14) In the above embodiment, the projector using three liquid crystal light modulation devices has been described as an example, but the present invention is not limited to this. The present invention can also be applied to a projector using one, two, four or more liquid crystal light modulation devices.

(15) The present invention is applied to a rear projection type projector that projects from a side opposite to the side that observes the projected image, even when applied to a front projection type projector that projects from the side that observes the projected image. Is also possible.

(16) In the above embodiment, an example in which the light source device of the present invention is applied to a projector has been described, but the present invention is not limited to this. For example, the light source device of the present invention can also be applied to other optical devices (for example, an optical disk device, an automobile headlamp, a lighting device, etc.).

DESCRIPTION OF SYMBOLS 10, 14, 16, 18 ... Light source device, 20 ... Solid light source array, 22 ... Board | substrate, 24 ... Solid light source, 30 ... Collimator lens array, 32 ... Collimator lens, 40, 44, 46, 48 ... Integrator optical system , 41 ... connecting portion, 50, 53, 54, 55 ... first microlens array, 51, 51a, 51b, 51c, 56 ... first microlens, 58, 58b, 58c, 59 ... first refractive power reducing layer, 60, 64, 65, 67 ... 2nd micro lens array, 61, 66 ... 2nd micro lens, 68, 69 ... 2nd refractive power reduction layer, 70 ... Superimposition lens, 80 ... Fluorescence production | generation part, 82 ... Transparent member, 84 ... Fluorescent layer, 90 ... Collimator optical system, 92 ... First lens, 94 ... Second lens, 100 ... Illuminator, 100ax ... Illumination optical axis, 110 ... Lens integrator Academic system, 120 ... first lens array, 122 ... first small lens, 130 ... second lens array, 132 ... second small lens, 140 ... polarization conversion element, 150 ... superimposed lens, 200 ... color separation light guide optical system 210, 220 ... Dichroic mirror, 230, 240, 250 ... Reflection mirror, 260, 270 ... Relay lens, 300R, 300G, 300B ... Condensing lens, 400R, 400G, 400B ... Liquid crystal light modulator, 500 ... Cross dichroic prism , 600 ... projection optical system, 1000 ... projector, SCR ... screen

Claims (8)

A plurality of solid state light sources;
A plurality of collimator lenses provided corresponding to each of the plurality of solid state light sources, and substantially collimating light generated by the plurality of solid state light sources, respectively;
A first microlens array having a plurality of first microlenses greater than the number of the plurality of collimator lenses; a second microlens array having a plurality of second microlenses corresponding to the plurality of first microlenses; A light source device including an integrator optical system having a superimposing optical system that superimposes a plurality of partial light beams from a plurality of second microlenses on a predetermined minute superimposing region,
The first microlens array includes a plurality of plano-convex microlenses as the plurality of first microlenses, and is disposed in contact with a convex surface of the plurality of first microlenses, and a refractive index of the first microlens. A first refractive power reduction layer having a refractive index intermediate to that of air;
The second microlens array includes a plurality of planoconvex microlenses as the plurality of second microlenses, and is disposed in contact with the convex surface of the plurality of second microlenses, and the refractive index of the second microlens. A light source device further comprising a second refractive power reduction layer having a refractive index intermediate to that of air. The light source device according to claim 1,
The refractive index of the first refractive power reduction layer is na1, the refractive index of the second refractive power reduction layer is na2, the refractive index of the first microlens is nb1, and the refractive index of the second microlens is nb2. The light source device satisfies the relationship of “0 <nb1-na1 <0.1” and “0 <nb2-na2 <0.1”. The light source device according to claim 1 or 2,
The solid-state light source comprises a semiconductor laser. In the light source device in any one of Claims 1-3,
The light source device, wherein the small overlap region has a size included in a square having a side of 1 mm. In the light source device in any one of Claims 1-4,
The number of the first micro lenses and the second micro lenses is 100 times or more the number of the collimator lenses. In the light source device according to any one of claims 1 to 5,
A light source device further comprising a fluorescent layer that is located at or near the position where light from the integrator optical system is superimposed and generates fluorescence from part or all of the light from the superimposing optical system. In the light source device according to any one of claims 1 to 5,
A light source device further comprising a transmission type diffusing unit that is positioned at or near the position where the light from the integrator optical system is superimposed and allows the light from the superimposing optical system to pass through while diffusing. A lighting device comprising the light source device according to any one of claims 1 to 7,
A light modulation device that modulates light from the illumination device according to image information;
A projector comprising: a projection optical system that projects light from the light modulation device.