JP2013041760A - Lighting device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device with a further improved light use efficiency than a prior art.SOLUTION: The lighting device 100 includes a light source device 110 emitting light, a first lens array 120 with a plurality of first micro lenses 122, a second lens array 130 with a plurality of second micro lenses 132 corresponding to the plurality of first micro lenses 122, and a superposing lens 150 for superposing light from the second lens array 130. In the lighting device 100, when a point where light passing through the first micro lenses 122 most gathers is a focussed point, a curvature of the first micro lens 122 is set for each lens 122 so that the focussed point is to be positioned in, or in the vicinity of, a given optical element which is situated further toward rear steps than the first lens array 120.

Description

  The present invention relates to a lighting device and a projector.

  Conventionally, a light source device that emits light, a first lens array having a plurality of first small lenses, a second lens array having a plurality of second small lenses corresponding to the plurality of first small lenses, and a second lens 2. Description of the Related Art An illumination device that includes a superimposing lens that superimposes light from an array is known. Moreover, a projector provided with such an illumination device is known (for example, refer to Patent Document 1).

  According to the conventional illumination device, the light from the first lens array having the plurality of first small lenses, the second lens array having the plurality of second small lenses corresponding to the plurality of first small lenses, and the second lens array Therefore, the in-plane light intensity distribution of the light from the light source device can be made uniform, and as a result, illumination light with less uneven brightness can be emitted.

JP 2007-219442 A

  Incidentally, in the technical field of lighting devices, it is always required to further increase the light utilization efficiency. However, the conventional lighting device has a problem that it is difficult to increase the light use efficiency.

  Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an illuminating device capable of further increasing light use efficiency as compared with the conventional art. It is another object of the present invention to provide a projector that includes the illumination device as described above and can further increase the light use efficiency.

  As a result of extensive research, the inventor of the present invention, as one of the reasons why it is difficult to increase the light utilization efficiency in the conventional lighting device, the point where the light that has passed through the first small lens gathers most is the focusing point. In the conventional illuminating device, since the focusing point is located at a position far away for each light that has passed through each first small lens, the light from the first small lens is transmitted to the optical element (second lens array) in the subsequent stage. Etc.), it was found that part of the light may be lost when passing through (see comparative examples described later). This is because, in the conventional lighting device, the same curvature is generally adopted for all the first small lenses from the viewpoint of ease of design and manufacture.

  As a result of further research, the curvature of each first small lens is set so that the focal point is located in or near the predetermined optical element that is behind the first lens array. The present invention has been conceived and the present invention has been completed. The present invention is constituted by the following matters.

[1] An illumination device of the present invention includes a light source device that emits light, a first lens array that includes a plurality of first small lenses, and a plurality of second small lenses that correspond to the plurality of first small lenses. An illuminating device comprising a second lens array and a superimposing lens for superimposing light from the second lens array, wherein a point at which the light that has passed through the first small lens gathers most is a focusing point. The curvature of one small lens is set for each of the first small lenses so that the focal point is located in or near a predetermined optical element that is subsequent to the first lens array. It is characterized by that.

  For this reason, according to the illumination device of the present invention, the curvature of the first small lens is set so that the focal point is located in or near the predetermined optical element at the rear stage of the first lens array. Since it is set for each first small lens, it is possible to prevent a part of the light from being lost when the light passes through a predetermined optical element. It becomes possible to make it higher (see the embodiment described later).

  Further, according to the illumination device of the present invention, since the first lens array, the second lens array, and the superimposing lens are provided, the in-plane light intensity distribution of the light from the light source device is obtained as in the conventional illumination device. It is possible to make uniform, and as a result, it is possible to emit illumination light with less uneven brightness.

[2] In the illumination device of the present invention, it is preferable that the first small lens is smaller than the second small lens corresponding to the first small lens.

  With such a configuration, it is possible to use a light source device that is smaller than the illuminable area of the emitted light, and as a result, it is possible to reduce the size and cost of the illumination device. .

  In the illumination device as described in [2] above, since the optical axis is expanded from the first lens array toward the second lens array, the light is incident on the first lens array so as to spread. For this reason, the spread of light incident on the first small lens in the central portion of the first lens array is different from the spread of light incident on the first small lens in the peripheral portion of the first lens array. Therefore, when the curvature of the first small lens is constant, the focusing point is located away from the optical element (see the later-described embodiments and comparative examples). Therefore, the present invention can be particularly preferably applied to the illumination device as described in [2] above.

[3] In the illuminating device of the present invention, the light that is disposed between the second lens array and the superimposing lens, and is composed of approximately one type of linearly polarized light in which the light from the second lens array is aligned in the polarization direction. It is preferable to further include a polarization conversion element that emits as follows.

  By adopting such a configuration, it becomes possible to emit light composed of approximately one type of linearly polarized light having a uniform polarization direction from the illumination device, and a device that uses light composed of linearly polarized light (for example, a liquid crystal light modulation device) It is possible to provide an illumination device suitable for use in a projector equipped with the projector.

[4] In the illumination device of the present invention, it is preferable that the predetermined optical element is a second lens array.

  By adopting such a configuration, it is possible to suppress the loss of part of the light when the light from the first small lens passes through the second lens array, thereby further improving the light use efficiency. It becomes possible to make it higher.

[5] In the illumination device of the present invention, it is preferable that the predetermined optical element is a polarization conversion element.

  By adopting such a configuration, it becomes possible to prevent a part of the light from being lost when the light from the first small lens passes through the polarization conversion element, thereby further improving the light utilization efficiency. It becomes possible to do.

[6] In the illuminating device of the present invention, it is preferable that the predetermined optical element is a second lens array and a polarization conversion element, and the focusing point is between the second lens array and the polarization conversion element.

  By adopting such a configuration, it is possible to prevent a part of the light from being lost when the light from the first small lens passes through both the second lens array and the polarization conversion element. Thus, the light utilization efficiency can be further increased.

  In this case, the curvature of the first small lens is set for each first small lens so that the focal point is located in the vicinity of both the optical elements of the second lens array and the polarization conversion element.

[7] In the illumination device of the present invention, it is preferable that the first small lens is a plano-convex lens having a spherical surface.

  With this configuration, the first lens array is used rather than using a first small lens having another shape (for example, a first small lens made of a biconvex lens or a first small lens made of a plano-convex lens having an aspherical curved surface). It becomes possible to make it easy to design.

[8] In the illumination device of the present invention, the first small lens is a plano-convex lens, the plurality of first small lenses are arranged in a matrix, and the curved surface of the plano-convex lens has a curvature in a row direction. It is preferable that the curved surface is composed of curved surfaces in which the curvature in the column direction is set separately.

  By setting it as such a structure, it becomes possible to adjust the position of a condensing point by setting a curvature about both the vertical and horizontal directions, As a result, it becomes possible to make light utilization efficiency still higher.

[9] A projector according to the present invention includes the illumination device according to the present invention, a light modulation device that modulates light from the illumination device according to image information, and projection optics that projects light from the light modulation device onto a projection target. And a system.

  According to the projector of the present invention, since the illumination device of the present invention that can further increase the light utilization efficiency than the conventional one is provided, the light utilization efficiency can be further enhanced as the whole projector.

FIG. 2 is a plan view showing an optical system of the projector 1000 according to the embodiment. The figure which looked at the 1st lens array 120 in an embodiment from the 2nd lens array 130 side. The figure which shows the mode of the light in the illuminating device 100 which concerns on embodiment. The figure which shows the mode of the light in the illuminating device 100a which concerns on a comparative example.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an illumination device and a projector of the present invention will be described based on 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 each drawing including FIG. 1, the light source device 110 is shown as a cross-sectional view. 1 and 2 are schematic diagrams, and the shape of the optical element in the drawings is not necessarily in accordance with reality.
FIG. 2 is a diagram of the first lens array 120 in the embodiment as viewed from the second lens array 130 side. The numbers A-1 to D-6 (small lens numbers) displayed on each first small lens 122 (not shown) in FIG. 2 are symbols for distinguishing the first small lenses 122. It does not indicate that the numbers are actually attached.
FIG. 3 is a diagram illustrating a state of light in the illumination device 100 according to the embodiment. The state of light shown in FIG. 3 is obtained by simulation. For this reason, descriptions of the light source device 110 other than the light emitting unit 13 and the reflector 20 are omitted. The same applies to FIG. 4 described later.

  In the following description, three directions orthogonal to each other are defined as a z-axis direction (illumination optical axis 100ax direction in FIG. 1), an x-axis direction (a direction parallel to the paper surface in FIG. 1 and perpendicular to the z-axis) and y, respectively. An axial direction (direction perpendicular to the paper surface in FIG. 1 and perpendicular to the z-axis) is assumed.

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, and three liquid crystal light modulation devices 400R that modulate red light, green light, and blue light, respectively. 400G and 400B, a cross dichroic prism 500, and a projection optical system 600 are provided.
The illumination device 100 includes a light source device 110, a concave lens 90, a first lens array 120, a second lens array 130, a polarization conversion element 140, and a superimposing lens 150. The illumination 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) along the illumination optical axis 100ax.

  As shown in FIG. 1, the light source device 110 includes an arc tube 10 and a reflector 20. The light source device 110 emits focused light having the illumination optical axis 100ax as the central axis toward the illuminated area.

  The arc tube 10 includes a tube bulb 12 containing the light emitter 13, a pair of sealing portions 14 and 16 extending on both sides of the tube bulb 12, a pair of electrodes disposed along the illumination optical axis 100ax, and a pair of seals. A pair of metal foils respectively sealed in the stoppers 14 and 16 and a pair of lead wires electrically connected to the pair of metal foils are provided. As the arc tube 10, various arc tubes that emit light with high luminance can be employed, for example, a metal halide lamp, a high-pressure mercury lamp, an ultra-high pressure mercury lamp, or the like. The light emitting unit 13 is located in the vicinity of a first focal point of a reflection surface 24 described later. The light emitting unit 13 emits light including red light, green light, and blue light.

  Illustratively showing the conditions of the components of the arc tube 10, the tube bulb portion 12 and the sealing portions 14 and 16 are made of, for example, quartz glass, and in the bulb portion 12, mercury, rare gas, and a small amount of Halogen is enclosed. The electrode is, for example, a tungsten electrode, and the metal foil is, for example, a molybdenum foil. The lead wire is made of, for example, molybdenum or tungsten.

  The reflector 20 is disposed in the first sealing portion 14 that is one sealing portion of the pair of sealing portions 14 and 16, and reflects the light emitted from the light emitting portion 13 toward the illuminated region. The reflector 20 includes an opening 22 for inserting and fixing the first sealing portion 14 of the arc tube 10 and a reflection surface 24 that reflects light toward the illuminated area. The reflecting surface 24 is an elliptical surface, and reflects the light emitted from the light emitting unit 13 located in the vicinity of the first focal point as the condensed light gathered in the vicinity of the second focal point on the illuminated region side. The reflector 20 is disposed in the first sealing portion 14 with an inorganic adhesive such as cement filled in the opening 22.

For example, crystallized glass, alumina (Al ₂ O ₃ ), or the like can be suitably used as a material for the base material constituting the reflecting surface 24. On the inner surface of the reflecting surface 24, for example, a visible light reflecting layer made of a dielectric multilayer film of titanium oxide (TiO ₂ ) and silicon oxide (SiO ₂ ) is formed.

  As shown in FIG. 1, the concave lens 90 is arranged on the illuminated region side of the reflector 20 and is configured to emit light from the reflector 20 toward the first lens array 120. The concave lens 90 makes the light incident on the first lens array 120 so that the light spreads.

  The first lens array 120, the second lens array 130, and the superimposing lens 150 constitute a light uniformizing optical system (so-called lens integrator optical system) that uniformizes the in-plane light intensity distribution of the light incident on the light modulation device.

  As shown in FIGS. 1 to 3, the first lens array 120 has a plurality of first small lenses 122 for dividing the light from the concave lens 90 into a plurality of partial light beams. The first lens array 120 has a function as a beam splitting optical element that splits light from the light source device 110 into a plurality of partial 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 6 rows and 4 columns (see FIG. 2). Although the detailed description is omitted, the outer shape (horizontal: vertical = 4: 3 rectangle) of the first small lens 122 is substantially similar to the outer shape of the image forming area of the liquid crystal light modulators 400R, 400G, and 400B. .

  In the illuminating device 100 according to the embodiment, when the point at which the light that has passed through the first small lens 122 gathers most is the focal point, the curvature of the first small lens 122 is that the focal point is downstream of the first lens array 120. It is set for each first small lens 122 (for each of A-1 to D-6) so as to be located in a certain predetermined optical element or in the vicinity of the predetermined optical element. In the present embodiment, as shown in FIG. 3, the predetermined optical element is the second lens array 130, and the focusing point is in the vicinity of the exit surface of the second lens array 130. Note that the present invention is not limited to this, and the focal point may be in the second lens array or in the vicinity of the incident surface of the second lens array. The first small lens 122 is a plano-convex lens having a spherical curved surface.

  The curvature of each first small lens 122 is obtained by, for example, performing a simulation to determine the curvature of each first small lens 122 at which the focal point is located in or near the predetermined optical element. It can be set based on the result. In the present invention, the curvatures of the first small lenses may all be different, or two or more first small lenses having the same curvature may be provided.

As shown in FIG. 1, the first small lens 122 is smaller than a second small lens 132 (described later) corresponding to the first small lens 122. Therefore, the first lens array 120 is smaller than the second lens array 130, and the optical axis is expanded from the first lens array 120 toward the second lens array 130.
Yes. As shown in FIG. 3, the first lens array 120 refracts light so that the optical axis of the light passing through the first small lens 122 is expanded, and the light passing through the first small lens 122 corresponds to the corresponding second small lens 132. To enter.

  The second lens array 130 has a plurality of second small lenses 132 corresponding to the plurality of first small lenses 122. 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 6 rows and 4 columns in a plane orthogonal to the illumination optical axis 100ax.

The polarization conversion element 140 emits the light from the second lens array 130 (each partial light beam divided by the first lens array 120) as light composed of approximately one type of linearly polarized light having the same polarization direction. It is.
The polarization conversion element 140 transmits one linearly polarized light component of the polarized light components included in the light from the light source device 110 as it is and reflects the other linearly polarized light 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 collects each partial light flux (originally light from the second lens array 130) from the polarization conversion element 140 and superimposes it on the vicinity of the image forming area of the liquid crystal light modulators 400R, 400G, 400B. This is an optical element. 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 further reflected by the reflection mirror 230, passes through the condenser lens 300R, and enters the image forming area 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 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 embodiment, the length of the optical path of blue light is long, and thus such a configuration is adopted. For example, the length of the optical path of red light is increased, and the relay lens and the reflection mirror are made red light. It is good also as a structure used for these optical paths.

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 outer diameter shape of the image forming region in each liquid crystal light modulation device is a rectangular shape of horizontal: vertical = 4: 3.

  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 which four right-angle prisms are bonded together when viewed from the y-axis direction, and a dielectric multilayer film is formed on a substantially X-shaped interface in which the right-angle prisms are bonded to each other. Has been. 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 to form an image on the screen SCR that is a projection target.

  Next, effects of the illumination device 100 and the projector 1000 according to the embodiment will be described.

  According to the illuminating device 100 according to the embodiment, the curvature of the first small lens 122 is determined in the predetermined optical element whose focal point is subsequent to the first lens array 120 or in the vicinity of the predetermined optical element (the second lens array 130). Is set for each first small lens so as to be positioned in the vicinity of the incident surface), a part of the light is lost when the light passes through a predetermined optical element (second lens array 120). It becomes possible to suppress this, and as a result, it becomes possible to make light utilization efficiency still higher than before.

  According to the illumination device 100 according to the embodiment, since the first lens array 120, the second lens array 130, and the superimposing lens 150 are provided, the in-plane light of the light from the light source device is provided as in the conventional illumination device. It is possible to make the intensity distribution uniform, and as a result, it is possible to emit illumination light with less brightness unevenness.

  Moreover, according to the illuminating device 100 which concerns on embodiment, since the 1st small lens 122 is smaller than the 2nd small lens 132 corresponding to the 1st small lens 122, it is small compared with the illumination possible area of the emitted light. Thus, it is possible to reduce the size and cost of the lighting device.

  Moreover, according to the illuminating device 100 which concerns on embodiment, since the polarization conversion element 140 is provided, it becomes possible to inject | emit the light which consists of substantially one type of linearly polarized light with which the polarization direction was equalized from the illuminating device, and consists of linear deflection | deviation. It is possible to provide an illumination device suitable for use in equipment that uses light.

  Moreover, according to the illuminating device 100 which concerns on embodiment, since a predetermined | prescribed optical element is the 2nd lens array 120, when the light from a 1st small lens passes a 2nd lens array, a part of the said light It is possible to suppress the loss of light and to further increase the light utilization efficiency.

  Moreover, according to the illuminating device 100 which concerns on embodiment, since the 1st small lens 122 consists of a plano-convex lens with a curved surface, it is the 1st small lens of another shape (For example, the 1st small lens and curved surface which consist of a biconvex lens, for example) The first lens array can be designed more easily than using a first small lens made of an aspheric plano-convex lens.

  According to the projector 1000 according to the embodiment, since the illumination device 100 according to the embodiment 1 is provided, the entire projector is provided with the illumination device 100 according to the embodiment 1 that can further increase the light utilization efficiency as compared with the related art. However, the light utilization efficiency can be further increased.

[Comparative example]
FIG. 4 is a diagram illustrating a state of light in the illumination device 100a according to the comparative example.
As a comparative example, a simulation for confirming the position of the focusing point was performed for the lighting device 100a having the same configuration as the conventional lighting device.
About the illuminating device 100a, the said simulation was performed as what has the structure similar to the illuminating device 100 which concerns on embodiment except the curvature of a 1st small lens. That is, in the illumination device 100a according to the comparative example, the curvatures of the first small lenses 122a in the first lens array 120a are all set equal.

  As a result of the simulation, as shown in FIG. 4, in the illumination device 100a having the same configuration as the conventional illumination device, the first lens array 120a to the second lens array are similar to the illumination device 100 according to the first embodiment. Since the optical axis is expanded toward 130, the light is incident on the first lens array 120a so that the light is expanded. Therefore, the spread of light incident on the first small lens 122a in the central portion of the first lens array 120a is different from the spread of light incident on the first small lens 122a in the peripheral portion of the first lens array 120a. Become. That is, in the first small lens 122a in the vicinity of the center, the difference in the incident angle of the incident light is larger than that in the first small lens 122a in the peripheral portion. In the first small lens 122a, the difference in the incident angle of incident light is smaller than that of the first small lens in the central portion, so that the position of the focal point becomes closer, and as a result, the focal point becomes the first small lens. It was found that each light passing through 122a is located at a position far away (in this case, the front stage of the second lens array 130 and the rear stage of the polarization conversion element 140). For this reason, when the light from the first small lens 122a passes through the second lens array 130, part of the light may be lost. In the illumination device 100a having the same configuration as the conventional illumination device, It becomes difficult to increase the light utilization efficiency.

  On the other hand, in the illuminating device according to the present invention, as shown in the above-described embodiment, the curvature of the first small lens is the same as that in the predetermined optical element whose focusing point is behind the first lens array or in the predetermined lens. It is set for each first small lens so as to be positioned in the vicinity of the optical element (see FIG. 3). For this reason, it becomes possible to make light utilization efficiency high.

  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, the present invention has been described by taking the illumination device 100 including the first small lens 122 made of a plano-convex lens having a curved surface as an example, but the present invention is not limited to this. For example, the first small lens is a plano-convex lens, a plurality of first small lenses are arranged in a matrix, and the plano-convex lens has a curved surface in which the curvature in the row direction and the curvature in the column direction are set separately. It is good also as an illuminating device provided with a thing. By setting it as such a structure, it becomes possible to adjust the position of a condensing point by setting a curvature about both the vertical and horizontal directions, As a result, it becomes possible to make light utilization efficiency still higher.

(3) In the above embodiment, the liquid crystal light modulation devices 400R, 400G, and 400B that modulate red light, green light, and blue light are used as the light modulation devices, but the present invention is not limited to this. Absent. You may use the liquid crystal light modulation apparatus which modulates another color light (yellow light etc.).

(4) In the above embodiment, a light source device may be used that further includes a secondary mirror that reflects part or all of the light that is not directly incident on the reflector out of the light emitted from the light emitting unit.

(5) In the above-described embodiment, the reflector whose reflecting surface is an elliptical surface is used, but the present invention is not limited to this. For example, a reflector whose reflecting surface is a parabolic surface may be used. In this case, since parallel light can be emitted from the reflector, an optical element corresponding to the concave lens 90 in the embodiment may not be provided.

(6) 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.

(7) 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.

(8) 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.

(9) In the above embodiment, the predetermined optical element is the second lens array, but the present invention is not limited to this. For example, the predetermined optical element may be a polarization conversion element. By adopting such a configuration, it becomes possible to prevent a part of the light from being lost when the light from the first small lens passes through the polarization conversion element, thereby further improving the light utilization efficiency. It becomes possible to do. More specifically, when a light shielding film is formed on the incident side corresponding to the reflective layer of the polarization conversion element, it corresponds to the polarization separation layer when light from the first small lens enters the polarization conversion element. It is possible to suppress the occurrence of light that is incident on the portion corresponding to the reflective layer instead of being incident on the portion, and is blocked by the light-shielding film and part of the light is lost. In addition, when the light shielding film is not formed on the incident side corresponding to the reflective layer, the light incident on the reflective layer becomes a different polarization from the light incident on the polarization separation layer and is emitted from the polarization conversion element. It is possible to suppress that the polarization directions of some polarizations are different, and consequently, it is possible to suppress the loss of light having different polarizations.

(10) In the above embodiment, the predetermined optical element is the second lens array, but the present invention is not limited to this. For example, the predetermined optical element may be a second lens array and a polarization conversion element. In this case, the focusing point may be located between the second lens array and the polarization conversion element. By adopting such a configuration, it is possible to prevent a part of the light from being lost when the light from the first small lens passes through both the second lens array and the polarization conversion element. Thus, the light utilization efficiency can be further increased.

(11) In the above embodiment, the light source device having an arc tube is used, but the present invention is not limited to this. For example, a light source device having a solid light source (light emitting diode (LED), semiconductor laser (LD), etc.) may be used.

(12) In each of the above embodiments, the example in which the illumination 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 lighting device of the present invention can be applied to other optical devices (for example, an optical disk device, a car headlamp, a lighting device, etc.).

(13) 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.

DESCRIPTION OF SYMBOLS 10 ... Light emission tube, 12 ... Tube part, 13 ... Light emission part, 14 ... 1st sealing part, 16 ... 2nd sealing part, 20 ... Reflector, 22 ... Opening part, 24 ... Reflecting surface, 90 ... Concave lens, DESCRIPTION OF SYMBOLS 100, 100a ... Illuminating device, 100ax ... Illumination optical axis, 110 ... Light source device, 120, 120a ... 1st lens array, 122, 122a ... 1st small lens, 130 ... 2nd lens array, 132 ... 2nd small lens, DESCRIPTION OF SYMBOLS 140 ... Polarization conversion element, 150 ... Superposition lens, 200 ... Color separation light guide optical system, 210, 220 ... Dichroic mirror, 230, 240, 250 ... Reflection mirror, 260, 270 ... Relay lens, 300R, 300G, 300B ... Collection Optical lens, 400R, 400G, 400B ... Liquid crystal light modulator, 500 ... Cross dichroic prism, 600 ... Projection optical system, 1000 ... Projector , SCR ... screen

Claims (9)

A light source device that emits light, a first lens array having a plurality of first small lenses, a second lens array having a plurality of second small lenses corresponding to the plurality of first small lenses, and the second lens An illumination device comprising a superimposing lens for superimposing light from the array,
When the point where the light that has passed through the first small lens gathers most is a focusing point,
The curvature of the first small lens is set for each of the first small lenses so that the focal point is located in or near a predetermined optical element that is subsequent to the first lens array. A lighting device characterized by that. The lighting device according to claim 1.
The lighting device according to claim 1, wherein the first small lens is smaller than the second small lens corresponding to the first small lens. In the illuminating device in any one of Claim 1 or 2,
A polarization conversion element that is disposed between the second lens array and the superimposing lens and that emits light from the second lens array as light of substantially one type of linearly polarized light having a uniform polarization direction; A lighting device. In the illuminating device in any one of Claims 1-3,
The illumination device according to claim 1, wherein the predetermined optical element is a second lens array. The lighting device according to claim 3.
The illumination device, wherein the predetermined optical element is a polarization conversion element. The lighting device according to claim 3.
The predetermined optical elements are a second lens array and a polarization conversion element,
The illuminating device characterized in that the focal point is between the second lens array and the polarization conversion element. In the illuminating device in any one of Claims 1-6,
The lighting device according to claim 1, wherein the first small lens is a plano-convex lens having a curved surface. In the illuminating device in any one of Claims 1-6,
The first small lens is a plano-convex lens,
The plurality of first small lenses are arranged in a matrix,
The curved surface of the plano-convex lens includes a curved surface in which a curvature in a row direction and a curvature in a column direction are set separately. The lighting device according to any one of claims 1 to 8,
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 onto a projection target.

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