JP2012058638A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device capable of emitting light of high luminance, emitting the light of high light use efficiency usable for various applications, and reducing the weight of the light source device compared with conventional light source devices.SOLUTION: This light source device includes: a plurality of solid light sources; a plurality of collimator lenses substantially parallelizing the lights generated by the plurality of solid light sources; and a condensing optical system 40 condensing the lights from the plurality of collimator lenses to a prescribed condensing position. The condensing optical system 40 comprises a small lens assembly in which each of a plurality of small lenses that has a planar incidence plane and an aspherical-convex emission plane is disposed corresponding to each of the plurality of collimator lenses; and a prescribed step is provided on one plane of the incidence plane and the emission plane of the condensing optical system 40 such that a surface of at least one small lens out of the plurality of small lenses recedes along the optical axis of the light source device.

Description

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

Conventionally, 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 parallelizing light generated by the plurality of solid-state light sources, and the plurality of collimators There is known a light source device including a condensing optical system that condenses light from a lens at a predetermined condensing position. 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, a light collecting optical system for condensing light from a plurality of solid light sources at a predetermined light condensing position is provided, so that light that can be used with high light utilization efficiency in various applications is emitted. It becomes possible to do.

JP 2010-78975 A

  However, in the conventional light source device, it is necessary to provide a large condensing optical system in order to be able to condense light from a plurality of solid state light sources at a predetermined condensing position, thereby reducing the weight of the light source device. There is a problem that it becomes difficult.

  Accordingly, the present invention has been made to solve the above-described problems, and can emit light with high luminance, and can emit light that can be used with high light utilization efficiency in various applications. And it aims at providing the light source device which can aim at weight reduction of a light source device rather than the case of the conventional light source device. It is another object of the present invention to provide a lightweight projector having such a light source device.

[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 light source device comprising a lens and a condensing optical system for condensing light from the plurality of collimator lenses at a predetermined condensing position, wherein the condensing optical system has a flat entrance surface and an exit surface A plurality of small lenses, each of which is an aspherical convex surface, is composed of a small lens assembly arranged corresponding to each of the plurality of collimator lenses, and one of the entrance surface and the exit surface of the condensing optical system The surface is provided with a predetermined step so that the surface of at least one small lens among the plurality of small lenses is in a state of being retracted along the optical axis of the light source device.

  According to the light source device of the present invention, since a plurality of solid-state light sources are provided, it is possible to emit high-luminance light as in the case of the conventional light source device.

  In addition, according to the light source device of the present invention, the light source device includes a condensing optical system that condenses light from a plurality of solid state light sources at a predetermined condensing position. It is possible to emit usable light with high light utilization efficiency.

  According to the light source device of the present invention, the condensing optical system includes a plurality of small lenses each having a plane of incidence and an aspherical convex surface of the incident surface, corresponding to each of the plurality of collimator lenses. A state in which at least one small lens surface of a plurality of small lenses is retreated along the optical axis of the light source device on one of the entrance surface and the exit surface of the condensing optical system. Since the predetermined level difference is provided so that the incident surface and the exit surface are both continuous surfaces, it is possible to reduce the weight of the condensing optical system compared to a normal condensing optical system (condensing lens) in which both are continuous surfaces. Therefore, the light source device can be made lighter than the conventional light source device.

  For this reason, the light source device of the present invention can emit high-luminance light, can emit light that can be used with high light utilization efficiency in various applications, and is a conventional light source device. The light source device can be lighter than the light source device.

  In the light source device of the present invention, the “small lens assembly” includes not only a small lens assembly configured by collecting a plurality of small lenses, but also a small lens assembly produced by integral molding by a press molding method or the like. Is also included.

In this specification, “retreat” means that, on the entrance surface, the entrance surface approaches the exit surface along the optical axis, and on the exit surface, the exit surface approaches the entrance surface along the optical axis. Say.
In addition, “the surface of at least one small lens among a plurality of small lenses is in a state of being retracted along the optical axis of the light source device” means that one of the incident surface and the exit surface has a certain small lens. It means that the surface is set back along the optical axis of the light source device with respect to the surface of at least one adjacent small lens.

[2] In the light source device of the present invention, the incident surface of the condensing optical system is a continuous surface, and the light exiting from the collimator lenses is the predetermined surface on the exit surface of the condensing optical system. It is preferable that the radius of curvature of the exit surface is set for each of the plurality of small lenses according to the retraction amount of the exit surface so that the light is condensed at the condensing position.

  As described above, in the light source device of the present invention, the radius of curvature of the exit surface is set according to the retraction amount of the exit surface for each of the plurality of small lenses, so that all the light from each collimator lens is predetermined. The light is correctly collected at the light collecting position.

[3] In the light source device of the present invention, the exit surface of the condensing optical system is a continuous surface, and the entrance surface of the condensing optical system has a retraction amount set for each of the plurality of small lenses. It is preferable that

  By adopting such a configuration, the degree of weight reduction of the condensing optical system, the mechanical strength of the condensing optical system, and the manufacturing cost of the condensing optical system are comparatively weighed, and each of the small lenses has an exit surface. Can be determined as appropriate.

[4] In the light source device of the present invention, when the exit surface of the small lens is a hyperboloid, the conic coefficient of the hyperboloid is K, and the refractive index of the small lens is n, “K = −n It is preferable that the condition “ ² ” is satisfied.

  With such a configuration, light from the collimator lens can be accurately collected at a predetermined condensing position.

In the present specification, “K = −n ² ” does not only indicate that “K” and “−n ² ” are completely matched, but can be regarded as substantially matching. Indicates that the numbers are close. Specifically, when rounding off to the third decimal place, both numerical values up to the second decimal place should match.

[5] 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.

[6] In the light source device of the present invention, it is preferable that the light source device further includes a fluorescent layer that is located in the vicinity of the condensing position and generates fluorescence from part or all of the light from the condensing optical system.

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.

[7] In the light source device of the present invention, it is preferable that the light source device further includes a transmission type diffusing unit that is located in the vicinity of the condensing position and allows the light from the condensing optical system to pass through while diffusing.

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.

[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.

  Since the projector of the present invention includes the light source device of the present invention that can reduce the weight of the light source device as compared with the case of the conventional light source device, the projector becomes a lightweight projector.

FIG. 2 is a plan view showing an optical system of the projector 1000 according to the first embodiment. The figure which looked at the solid light source array 20 in Embodiment 1 from the collimator lens array 30 side. 3 is a graph showing the light emission intensity characteristics of the solid-state light source 24 and the light emission intensity characteristics of the phosphor in the first embodiment. The figure shown in order to demonstrate the shape of the condensing optical system 40 in Embodiment 1. FIG. The figure shown in order to demonstrate the condensing optical system 40a in a test example. The figure which shows the mode of the condensing by the condensing optical system 40a in a test example. FIG. 6 is a plan view showing an optical system of a light source device 12 according to a second embodiment. FIG. 6 is a diagram for explaining a shape of a condensing optical system in a second embodiment.

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

[Embodiment 1]
FIG. 1 is a plan view showing an optical system of a projector 1000 according to the first embodiment.
FIG. 2 is a diagram of the solid-state light source array 20 according to the first 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 first embodiment. FIG. 3A is a graph showing the light emission intensity characteristics of the solid-state light source 24, and FIG. 3B is a graph showing the light emission intensity characteristics of the phosphor contained in the fluorescent layer. 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 diagram for explaining the shape of the condensing optical system 40 in the first embodiment. 4A is a view of the condensing optical system 40 as viewed from the fluorescence generation unit 50 side, and FIG. 4B is a perspective view of the condensing optical system 40. In FIG. 4, a step is provided at the boundary represented by a solid line, and no step is provided at the boundary represented by a broken line. The same applies to FIG. 8 described later.
In each drawing, three directions orthogonal to each other are the z-axis direction (the illumination optical axis 100ax direction in FIG. 1), the x-axis direction (the direction parallel to the paper surface in FIG. 1 and perpendicular to the z-axis) and the y-axis. A direction (a direction perpendicular to the paper surface and perpendicular to the z-axis in FIG. 1) is displayed.

As shown in FIG. 1, the projector 1000 according to the first 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. A prism 500 and a projection optical system 600 are provided.
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, a condensing optical system 40, a fluorescence generation unit 50, and a collimator optical system 60.

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 56 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, 56 solid-state light sources 24 are arranged in a matrix of 7 rows and 8 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 56. 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 56 solid light sources 24, and each of the collimator lens arrays 30 substantially collimates the light generated by the 56 solid light sources 24. It has a meter lens 32 (only one is labeled). The 56 collimator lenses 32 are arranged in a matrix of 7 rows and 8 columns so as to correspond to the 56 solid light sources 24. Although a detailed description is omitted, the collimator lens 32 is formed of 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 56 as long as it corresponds to the number of solid light sources. Each collimator lens may be arranged discretely.

The condensing optical system 40 condenses the light from the 56 collimator lenses at a predetermined condensing position.
As shown in FIGS. 1 and 4, the condensing optical system 40 includes 56 small lenses each having a flat entrance surface and an aspheric convex surface corresponding to each of the 56 collimator lenses 32. It consists of a small lens assembly arranged. The entrance surface of the condensing optical system 40 is a continuous surface, and the exit surface of the condensing optical system 40 is along the optical axis of the light source device 10 (in the first embodiment, coincides with the illumination optical axis 100ax) toward the center. Steps are provided so as to be largely retracted. Therefore, the condensing optical system 40 indicates that “the surface of at least one small lens among the plurality of small lenses is along the optical axis of the light source device on one of the incident surface and the exit surface of the condensing optical system. The condition that “a predetermined step is provided so as to be in a retracted state” is satisfied.

In the condensing optical system 40, the exit surface of the small lens is a hyperboloid, and when the conic coefficient of the hyperboloid is K and the refractive index of the small lens is n, the condition of “K = −n ² ” is satisfied. Fulfill. That is, for example, when 56 small lenses are made of PMMA (polymethyl methacrylate resin) with n = 1.50, the above condition is satisfied if K is −2.25.

  Further, in the condensing optical system 40, the light emitted from each collimator lens 32 is emitted in accordance with the retraction amount of the exit surface for each of the plurality of small lenses so that all the light from the collimator lenses 32 is collected at a predetermined condensing position. The radius of curvature of the surface is set.

  The fluorescence generation unit 50 is located in the vicinity of the condensing position, and red light (emission intensity peak: about 610 nm) and green light (emission intensity peak: about 550 nm) from a part of the light from the condensing optical system 40. The fluorescent layer 54 is generated (see FIG. 3B). Further, it has a transparent member 52 that carries the fluorescent layer 54. The fluorescence generation unit 50 emits light (that is, light that can be used as white light) including blue light passing through the fluorescent layer 54 together with fluorescence (red light and green light) without being involved in the generation of fluorescence. The fluorescence generation unit 50 has a square plate shape as a whole and is fixed at a predetermined position (see FIG. 1).

  The transparent member 52 allows at least light (blue light) from the condensing optical system 40 to pass therethrough. The transparent member 52 is made of optical glass, for example. Note that a layer (for example, a dielectric multilayer film) that transmits light from the condensing optical system and reflects fluorescence may be formed on the transparent member.

The fluorescent layer 54 is disposed at a position where light from the condensing optical system 40 enters the fluorescent layer 54 in a defocused state.
The fluorescent layer 54 is composed 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 54 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 54, the blue light is emitted from the fluorescence generation unit 50 as light having substantially the same distribution (so-called Lambertian distribution) characteristics as fluorescence.

The collimator optical system 60 makes the light from the fluorescence generation unit 50 substantially parallel. As shown in FIG. 1, the collimator optical system 60 includes a first lens 62 and a second lens 64.
The first lens 62 and the second lens 64 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 a 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. In the projector 1000 according to the first embodiment, the length of the optical path of the blue light is long, and thus such a configuration is adopted. However, the length of the optical path of the red light is increased, and the relay lens and the reflection mirror are made 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 form color images by modulating incident color light according to image information. It is. 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 first embodiment will be described.

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

  Further, according to the light source device 10 according to the first embodiment, the light source device 10 includes the condensing optical system 40 that condenses the light from the plurality of solid light sources 24 at a predetermined light condensing position, and thus, similarly to the case of the conventional light source device. It is possible to emit light that can be used with high light utilization efficiency in various applications.

  Further, according to the light source device 10 according to the first embodiment, in the condensing optical system 40, a plurality of small lenses whose incident surface is a flat surface and whose exit surface is an aspheric convex surface correspond to each of the plurality of collimator lenses 32. At least one small lens among a plurality of small lenses on one of the entrance surface and exit surface of the condensing optical system 40 (the exit surface in the first embodiment). Since a predetermined step is provided so that the surface of the lens is retracted along the optical axis of the light source device 10, a normal condensing optical system (condensing light) in which both the entrance surface and the exit surface are continuous surfaces. It is possible to reduce the weight of the condensing optical system as compared to the case of a lens), and thus it is possible to reduce the weight of the light source device as compared to the case of a conventional light source device.

  For this reason, the light source device 10 according to the first embodiment can emit high-luminance light, can emit light that can be used with high light utilization efficiency in various applications, and is a conventional one. The light source device can be lighter than the light source device.

  Further, according to the light source device 10 according to the first embodiment, the radius of curvature of the exit surface is set according to the retraction amount of the exit surface for each of the plurality of small lenses, so that the light from each collimator lens 32 is In either case, light is correctly collected at a predetermined light collection position.

Further, according to the light source device 10 according to the first embodiment, the exit surface of the small lens is a hyperboloid and satisfies the condition of “K = −n ² ”, so that the light from the collimator lens 32 has a predetermined concentration. It becomes possible to focus light on the position with high accuracy.

  Further, according to the light source device 10 according to the first embodiment, the solid-state light source 24 is composed of a semiconductor laser. Therefore, by integrating such semiconductor lasers at a high density, a compact and high-power light source device can be obtained. It becomes possible.

  Further, according to the light source device 10 according to the first embodiment, the fluorescent light (red light and green light) is generated from a part of the light (blue light) from the condensing optical system 40 that is located in the vicinity of the condensing position. Since the fluorescent layer 54 is provided, desired color light can be obtained using the solid-state light source 24 that generates specific color light.

  According to the projector 1000 according to the first embodiment, the light source device 10 according to the first embodiment, which can reduce the weight of the light source device as compared with the case of the conventional light source device, is provided.

[Test example]
In this test example, a simulation was performed to confirm whether the condensing optical system 40a defined by the present invention can correctly collect light from a plurality of collimator lenses at a predetermined condensing position.

FIG. 5 is a diagram for explaining the condensing optical system 40a. FIG. 5A shows the optical axis thickness of a plurality of small lenses in the condensing optical system 40a, and FIG. 5B shows the relationship between the optical axis thickness of the small lens, the radius of curvature, and the back focus (bf). It is a table | surface which displays. In FIG. 5A, the optical axis thickness of the small lens is shown in a box corresponding to the small lens.
In this test example, “the optical axis thickness of the small lens” is defined as follows. That is, when a virtual plano-convex lens is constructed by extrapolating the entrance surface and the exit surface of the target small lens, the thickness on the optical axis of the plano-convex lens is referred to as “optical axis thickness of the small lens”.
In this test example, “small lens back focus” is defined as follows. That is, the distance from the exit surface on the optical axis of the plano-convex lens to the focal point.
Note that the units of numerical values of the optical axis thickness, the radius of curvature, and the back focus (bf) are all in millimeters (mm).
FIG. 6 is a diagram showing a state of light collection by the light collection optical system 40a. In FIG. 6, the closer to white, the higher the intensity of incident light.

The condensing optical system 40a basically has the same configuration as the condensing optical system 40 in the first embodiment. However, in the condensing optical system 40a, the refractive index n is set to 1.533, and the conical coefficient K is set to -2.33504. In this case, the condition of “K = −n ² ” is satisfied.

  As can be seen from FIG. 5A, the optical axis thickness of the small lens located at the four corners is the largest (25 mm), and the optical axis thickness of the small lens located at the center is the smallest (5 mm).

  In the simulation, the optical parameters of the solid light source array 20a and the collimator lens array 30a (both not shown) having the same configuration as the solid light source array 20 and the collimator lens array 30 in the first embodiment, and the above-described light collection. The measurement was performed using each optical parameter of the optical system 40a.

  As a result of the simulation, as shown in FIG. 6, when the above-described condensing optical system 40a is used, the light from the plurality of collimator lenses is collected in a sufficiently small range of a 0.4 mm square. It was confirmed that light can be emitted, that is, light from a plurality of collimator lenses can be correctly condensed at a predetermined condensing position.

[Embodiment 2]
FIG. 7 is a plan view showing an optical system of the light source device 12 according to the second embodiment.
FIG. 8 is a view for explaining the shape of the condensing optical system 42 in the second embodiment. FIG. 8A is a view of the condensing optical system 42 as viewed from the fluorescence generation unit 50 side, and FIG. 8B is a perspective view of the condensing optical system 42.

  The light source device 12 according to the second embodiment basically has the same configuration as that of the light source device 10 according to the first embodiment, but is different from the light source device 10 according to the first embodiment in that a step is provided on the incident surface. Not the case. That is, in the light source device 12 according to the second embodiment, as illustrated in FIGS. 7 and 8, the light incident surface of the condensing optical system 42 includes several small lens surfaces among the plurality of small lenses. A predetermined step is provided so as to be in a state of being retracted along the optical axis. The entrance surface of the condensing optical system 42 is set to have a retraction amount for each of the plurality of small lenses, and a step is provided so that the center side is largely retracted along the optical axis of the light source device 12. ing.

  As described above, the light source device 12 according to the second embodiment is different from the light source device 10 according to the first embodiment in that a step is provided on the incident surface. A plurality of small lenses that are flat and have an aspherical convex surface are formed by a small lens assembly arranged corresponding to each of the plurality of collimator lenses 32, and the incident surface and the exit surface of the condensing optical system 42 are arranged. One of the surfaces (incident surface in the second embodiment) has a predetermined step so that the surface of at least one small lens among the plurality of small lenses is in a state of being retracted along the optical axis of the light source device 12. Therefore, as in the case of the light source device 10 according to the first embodiment, it is possible to emit high-luminance light and emit light that can be used with high light utilization efficiency in various applications. Of conventional light source devices It becomes capable source device to reduce the weight of the light source device than if.

  Further, according to the light source device 12 according to the second embodiment, since the incident surface of the condensing optical system 42 is set with a retraction amount for each of the plurality of small lenses, the degree of weight reduction of the condensing optical system, By comparing and considering the mechanical strength of the condensing optical system and the manufacturing cost of the condensing optical system, the retraction amount of the exit surface can be appropriately determined for each of the plurality of small lenses.

  The light source device 12 according to the second embodiment has the same configuration as the light source device 10 according to the first embodiment except that a step is provided on the incident surface. It has the corresponding effect as it is.

  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) In each of the above embodiments, a light source device that includes a fluorescent layer that generates fluorescence from a part of light from a condensing optical system and emits light including fluorescence is used. However, the present invention is limited to this. Is not to be done. 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. Also in this case, a light uniformizing means such as an integrator rod disposed in the vicinity of a predetermined light collecting position can be used.

(2) In each of the above embodiments, as the solid light source and the fluorescent layer, the solid light source 24 that generates blue light and the fluorescent layer 54 that generates fluorescence including red light and green light from a 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.

(3) In each of the above embodiments, the light source device 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.

(4) In each of the above embodiments, the solid light source 24 that generates blue light having a peak emission intensity of about 460 nm is used, but 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.

(5) In each of the above embodiments, 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.

(6) In each of the above embodiments, a transmissive projector is used, but 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.

(7) In each of the above embodiments, 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.

(8) In each of the above embodiments, a 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.

(9) The present invention can be 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.

(10) In each of the above embodiments, the 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 10,12 ... Light source device, 20 ... Solid light source array, 22 ... Board | substrate, 24 ... Solid light source, 30 ... Collimator lens array, 32 ... Collimator lens, 40, 42 ... Condensing optical system, 50 ... Fluorescence production | generation part, 52 ... transparent member, 54 ... fluorescent layer, 60 ... collimator optical system, 62 ... first lens, 64 ... second lens, 100 ... illuminating device, 100ax ... illumination optical axis, 110 ... lens integrator optical system, 120 ... first DESCRIPTION OF SYMBOLS 1 lens array, 122 ... 1st small lens, 130 ... 2nd lens array, 132 ... 2nd small lens, 140 ... Polarization conversion element, 150 ... Superposition lens, 200 ... Color separation light guide optical system, 210, 220 ... Dichroic Mirror, 230, 240, 250 ... reflective mirror, 260, 270 ... relay lens, 300R, 300G, 300B ... condensing lens, 400R, 40 G, 400B ... liquid crystal light modulation device, 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 light source device including a condensing optical system for condensing light from the plurality of collimator lenses at a predetermined condensing position,
The condensing optical system is composed of a small lens assembly in which a plurality of small lenses whose incident surface is a flat surface and whose exit surface is an aspheric convex surface are arranged corresponding to each of the plurality of collimator lenses,
One of the entrance surface and the exit surface of the condensing optical system is in a state where the surface of at least one small lens among the plurality of small lenses is retracted along the optical axis of the light source device. A light source device having a predetermined level difference as described above. The light source device according to claim 1,
The incident surface of the condensing optical system is a continuous surface,
The exit surface of the condensing optical system corresponds to the retraction amount of the exit surface for each of a plurality of small lenses so that all the light from each collimator lens is condensed at the predetermined condensing position. A light source device characterized in that a radius of curvature of the exit surface is set. The light source device according to claim 1,
The exit surface of the condensing optical system is a continuous surface,
The light source device according to claim 1, wherein a retraction amount is set for each of the plurality of small lenses on the incident surface of the condensing optical system. In the light source device in any one of Claims 1-3,
The exit surface of the small lens is a hyperboloid,
When the conic coefficient of the hyperboloid is K and the refractive index of the small lens is n,
A light source device satisfying a condition of “K = −n ² ”. In the light source device in any one of Claims 1-4,
The solid-state light source comprises a semiconductor laser. In the light source device according to any one of claims 1 to 5,
A light source device further comprising a fluorescent layer located near the condensing position and generating fluorescence from a part or all of the light from the condensing optical system. In the light source device according to any one of claims 1 to 5,
A light source device further comprising transmission type diffusing means that is positioned in the vicinity of the condensing position and allows light from the condensing 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.