JP5803412B2 - Optical element, lighting device, and projector - Google Patents

Description

  The present invention relates to an optical element, a lighting device, and a projector.

  As one of the devices that can display a large screen image, a small light modulation element that forms an optical image according to image information is illuminated with light from an illumination device, and the optical image is enlarged and displayed on a screen by a projection lens. Projectors that can be used.

  In order to improve the quality of the displayed image, it is important to illuminate the light modulation element with illumination light having a uniform intensity distribution (illuminance distribution). For this reason, the projector illumination device has an illumination light intensity distribution. For the purpose of uniformizing, an integrator optical system using a pair of lens arrays and rod lenses is used. Among these, a rod integrator using a rod lens is an optical system that obtains illumination light having a uniform intensity distribution on the exit surface of the rod lens by propagating light from the light source while reflecting the light from the inner surface of the rod lens.

  As an improved example of the rod integrator, a rod array integrator in which a plurality of rod lenses are arranged in parallel in a direction orthogonal to the optical axis of the rod lens (light propagation direction) has been proposed (for example, see Patent Document 1). In Patent Document 1, a rod array is configured by arranging small rod lenses having a small diameter in parallel in a matrix instead of a single rod lens, and a single rod having the same diameter as the rod array is formed at the exit end of the rod array. A lens is placed. In the rod array integrator configured as described above, light is incident on each of the small rod lenses, so the number of times of light reflection on the inner surface of the rod lens is dramatic compared to a rod integrator using a single rod lens. Therefore, illumination light with a more uniform intensity distribution (illuminance distribution) can be obtained at the exit end of each small rod lens. In addition, the single rod lens arranged on the exit end side of the rod array can mix the light that has passed through each small rod lens with each other, resulting in a very strong intensity distribution (illuminance distribution) in the end. Uniform illumination light can be obtained.

  In general, a rod array integrator having such a configuration is such that a rod array and a single rod lens arranged on the exit end side thereof are separately manufactured, and the exit end surface of the rod array and a single rod are formed. It is manufactured by connecting with an adhesive or the like so as not to cause a step between the incident end face of the lens.

JP 2005-140837 A

  However, it is very difficult to completely match the outer dimension and shape of the exit end face of the rod array formed by arranging a plurality of small rod lenses in a matrix in the same manner as the outer dimension and shape of the incident end face of the single rod lens. . Therefore, in the connection part of a rod array and a single rod lens, generation | occurrence | production of a level | step difference is unavoidable, this causes light leakage from a connection part, and optical transmission efficiency falls. In addition, when the level difference of the four side surfaces of the rod array integrator is different, the intensity of light leakage (illuminance distribution) obtained by the rod array integrator is deteriorated because the level of light leakage at each level difference is different. . Thus, the conventional rod array integrator has a problem that it is difficult to obtain illumination light with a uniform intensity distribution with high efficiency.

  The present invention has been made in view of the above problems, and one of the objects according to some aspects of the present invention is to obtain light with a more uniform intensity distribution than in the past with higher efficiency. It is to provide an optical element. Another object of some aspects of the present invention is to provide an illumination device and a projector including the above-described optical element.

The optical element according to the present invention is
An optical element having a first surface and a second surface facing each other,
A first rod integrator having a first end face and a second end face;
A second rod integrator having a third end face and a fourth end face;
A first medium and a second medium sandwiched between the first rod integrator and the second rod integrator;
Including
The first end surface and the third end surface constitute the first surface,
The second end surface and the fourth end surface constitute the second surface,
The first medium is located closer to the first surface than the second medium;
The second medium is located closer to the second surface than the first medium;
The refractive index of the first medium is smaller than the refractive index of the first rod integrator and the refractive index of the second rod integrator,
The refractive index of the second medium is equal to the refractive index of the first rod integrator and the refractive index of the second rod integrator.

  According to such an optical element, by having the first medium, the intensity distribution of the light incident from the first surface can be made uniform in each of the first rod integrator and the second rod integrator. By having the second medium, the light homogenized in the first rod integrator and the light homogenized in the second rod integrator can be mixed and further homogenized. Thereby, the light with uniform intensity distribution can be obtained.

  Furthermore, according to such an optical element, it is comprised by one rod integrator in the direction (direction along an optical axis) which goes to a 2nd surface from a 1st surface. That is, there is no connection portion in the direction from the first surface toward the second surface. Therefore, it is possible to prevent light leakage due to imperfection of the connection portion. Therefore, illumination light with a uniform intensity distribution can be obtained with high efficiency.

In the optical element according to the present invention,
The first medium and the second medium may be an adhesive member that joins the first rod integrator and the second rod integrator.

  According to such an optical element, the first medium and the second medium can function as an adhesive member. Therefore, for example, a member for joining the first rod integrator and the second rod integrator becomes unnecessary.

In the optical element according to the present invention,
The first medium and the second medium may be integrally formed optical members.

  According to such an optical element, the manufacturing process can be simplified.

In the optical element according to the present invention,
A third medium and a fourth medium sandwiched between the first rod integrator and the second rod integrator and located between the first medium and the second medium;
The third medium is located closer to the first medium than the fourth medium;
The fourth medium is located closer to the second medium than the third medium;
The refractive index of the third medium is equal to the refractive index of the first rod integrator and the refractive index of the second rod integrator,
The refractive index of the fourth medium may be smaller than the refractive index of the first rod integrator and the refractive index of the second rod integrator.

  According to such an optical element, the intensity distribution in each of the first rod integrator and the second rod integrator is made uniform, and the intensity in the optically integrated first rod integrator and the second rod integrator. The process of uniforming the distribution can be performed a plurality of times. Therefore, it is possible to obtain illumination light with high uniformity of intensity distribution.

In the optical element according to the present invention,
The refractive index of the first medium may increase from the first surface side toward the second surface side.

  According to such an optical element, since light propagates while gradually mixing between the first rod integrator and the second rod integrator, light with a more uniform intensity distribution (illuminance distribution) can be obtained. Furthermore, since light reflection at the boundary surface (boundary surface where the refractive index changes discretely) between the first medium and the second medium can be reduced, light can be guided with high efficiency.

In the optical element according to the present invention,
The first rod integrator and the second rod integrator may have a cross-sectional area that increases from the first surface toward the second surface.

  According to such an optical element, each time incident light is reflected at the boundary surface between the rod integrator and the first medium, the angle of the light beam with respect to the optical axis of the optical element can be reduced. The directivity of the emitted light can be increased.

In the optical element according to the present invention,
The first rod integrator and the second rod integrator may have a cross-sectional area that decreases from the first surface toward the second surface.

  According to such an optical element, since the light beam cross section of the light emitted from the second surface can be made smaller than the light beam cross section of the light incident on the first surface, the illumination target having a small irradiated surface is illuminated. In this case, it is preferable.

The lighting device according to the present invention includes:
An optical element according to the present invention;
A light source unit for generating light incident on the first surface of the optical element;
including.

  According to such an illuminating device, illumination light with a uniform intensity distribution can be obtained with high efficiency.

In the lighting device according to the present invention,
The light source unit is
A first light emitting element for generating light incident on the first end face of the first rod integrator;
A second light emitting element for generating light incident on the third end face of the second rod integrator;
You may have.

  According to such an illuminating device, the light intensity is large and uniform light can be obtained.

The projector according to the present invention is
A lighting device according to the present invention;
A light modulation device that modulates light emitted from the illumination device according to image information;
A projection device for projecting an image formed by the light modulation device;
including.

  According to such a projector, it is possible to use, as a light source, an illumination device that can obtain illumination light with a uniform intensity distribution with high efficiency. Therefore, for example, a bright image with little illuminance unevenness can be projected.

Schematic which shows the structure of the illuminating device which concerns on 1st Embodiment. The figure for demonstrating the structure of the optical element of the illuminating device which concerns on 1st Embodiment. The figure for demonstrating the structure of the optical element of the illuminating device which concerns on 1st Embodiment. The schematic diagram which looked at the optical element of the illuminating device which concerns on the 1st modification of 1st Embodiment from the light source part side. The schematic diagram which looked at the optical element of the illuminating device which concerns on the 1st modification of 1st Embodiment from the light source part side. The schematic diagram which looked at the optical element of the illuminating device which concerns on the 2nd modification of 1st Embodiment from the light source part side. The figure which shows typically the optical element of the illuminating device which concerns on the 3rd modification of 1st Embodiment. The figure which shows typically the optical element of the illuminating device which concerns on the 3rd modification of 1st Embodiment. The figure which shows typically the optical element of the illuminating device which concerns on the 4th modification of 1st Embodiment. The figure which shows typically the optical element of the illuminating device which concerns on 2nd Embodiment. The figure which shows typically the optical element of the illuminating device which concerns on the modification of 2nd Embodiment. The figure which shows typically the optical element of the illuminating device which concerns on 3rd Embodiment. Schematic which shows the structure of the illuminating device which concerns on 4th Embodiment. FIG. 10 is a diagram schematically illustrating a projector according to a fifth embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. First embodiment 1.1. Configuration of Lighting Device First, the configuration of the lighting device according to the first embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating a configuration of an illumination device 100 according to the first embodiment. The illumination device 100 according to the first embodiment includes the optical element according to the present invention.

  As illustrated in FIG. 1, the illumination device 100 includes a light source unit 10, a condensing element 20, and an optical element 30.

  The light source unit 10 includes a light emitting element 11 and a light distribution angle control element 12.

  The light emitting element 11 generates light. The light distribution angle control element 12 has a function of converting the angle distribution (radiation angle) of the light emitted from the light emitting element 11 into a predetermined value.

  The condensing element 20 has a function of increasing the incident efficiency of light from the light source unit 10 to the optical element 30. However, the condensing element 20 may not be provided depending on the angular distribution of light emitted from the light source unit 10 or the like. The optical element 30 functions as a uniform light guiding element that makes the intensity distribution of light emitted from the optical element 30 uniform by propagating light in the z direction.

  As the light emitting element 11, for example, a semiconductor laser (Laser Diode), a super luminescent diode (Super Luminescent Diode), an LED (Light Emitting Diode), an OLED (Organic Light Emitting Diode), a discharge lamp (for example, a Xenon lamp, for example) High pressure mercury lamp). Further, as the light distribution angle control element 12 and the light condensing element 20, a lens, a mirror, a holographic element, and a combination thereof can be used.

  The light emitted from the light source unit 10 is converted into light having a predetermined angular distribution by the light distribution angle control element 12 and enters the optical element 30 through the condensing element 20. The light incident on the optical element 30 has a uniform intensity distribution while propagating in the z direction, and illuminates the illumination target 90 with illumination light having a uniform intensity distribution.

  Next, the configuration of the optical element 30 will be described.

  2 and 3 are diagrams for explaining the configuration of the optical element 30. FIG. FIG. 2A is a schematic view of the optical element 30 as viewed from the light source unit 10 side. FIG. 2B is a schematic view of the optical element 30 as viewed from the illumination object 90 side. 3 is an enlarged view of a portion surrounded by a one-dot chain line III in FIG. 2 and 3 are exaggerated for convenience, and the dimensional relationships in FIGS. 1 to 3 are not accurate.

  As shown in FIGS. 1 to 3, the optical element 30 includes a plurality of rod integrators 31 made of a light-transmitting medium having a refractive index n1, and two types of adhesive members having different refractive indices (refractive index n0, refractive index n1). 32A, 32B.

  The rod integrator 31 has an incident end face 3, an exit end face 4, and a connection surface 5 that connects the entrance end face 3 and the exit end face 4. In the illustrated example, the incident end face 3 and the exit end face 4 are opposed to each other. As shown in FIG. 3, the rod integrator 31 has a shape extending along the z direction from the incident end face 3 on which light generated by the light source unit 10 is incident to the exit end face 4 that emits uniformized illumination light. doing. In the illustrated example, the rod integrator 31 is a rectangular parallelepiped. The z direction is a direction along the optical axis L (the direction in which light is propagated) L of the optical element 30. The x direction is a direction orthogonal to the z direction, and the y direction is a direction orthogonal to the z direction and the x direction.

  As shown in FIGS. 2A and 2B, in the optical element 30, a plurality of rod integrators 31 having at least equal dimensions in the z direction are arranged in parallel in the x direction and the y direction. In the illustrated example, the parallel number in the x direction is 6, and the parallel number in the y direction is 6. Note that the number of parallel in the x direction and the y direction is not particularly limited.

  Between the adjacent rod integrators 31, the first adhesive member 32 </ b> A and the second adhesive member 32 </ b> B are filled without a gap, and the adjacent rod integrators 31 are integrated (bonded) via these adhesive members 32 </ b> A and 32 </ b> B. ing. That is, the plurality of rod integrators 31 are integrated by the first and second adhesive members 32A and 32B, and form an optical element 30 having a quadrangular prism shape. In the illustrated example, 36 rod integrators 31 having the same shape and the same size constitute the optical element 30.

  The optical element 30 has an incident surface (first surface) 1 on which light generated by the light source unit 10 is incident, and an exit surface (second surface) 2 that equalizes the incident light and emits it as illumination light. The entrance surface 1 and the exit surface 2 are opposed to each other.

  As shown in FIG. 2A, the incident surface (first surface) 1 of the optical element 30 includes the incident end surfaces 3 of the plurality of rod integrators 31. The shape of the incident end face 3 of the rod integrator 31 is a square in the illustrated example. The incident surface 1 of the optical element 30 is provided by, for example, arranging a plurality of incident end surfaces 3 in a close-packed manner. The shape of the incident surface 1 of the optical element 30 is, for example, a square.

  As shown in FIG. 2B, the exit surface (second surface) 2 of the optical element 30 includes the exit end surfaces 4 of the plurality of rod integrators 31. The shape of the injection end face 4 of the rod integrator 31 is a square in the illustrated example. The exit surface 2 of the optical element 30 is provided by, for example, arranging a plurality of exit end surfaces 4 in a close-packed manner. The shape of the exit surface 2 of the optical element 30 is, for example, a square.

As shown in FIG. 3, the first adhesive member 32 </ b> A and the second adhesive member 32 </ b> B are sandwiched between adjacent rod integrators 31. As shown in FIG. 3, when the adjacent rod integrators 31 of the plurality of rod integrators 31 constituting the optical element 30 are a first rod integrator 31A and a second rod integrator 31B, the first adhesive member 32A and the first The second adhesive member 32B is sandwiched between the first rod integrator 31A and the second rod integrator 31B. Specifically, the first adhesive member 32A and the second adhesive member 32B are located between the connection surface 5a of the first rod integrator 31A and the connection surface 5b of the second rod integrator 31B. As shown in FIG. 3, the incident end surface (first end surface) 3 a of the first rod integrator 31 and the incident end surface ( third end surface) 3 b of the second rod integrator 31 constitute an incident surface 1. The exit end face ( second end face) 4 a of the first rod integrator 31 and the exit end face (fourth end face) 4 b of the second rod integrator 31 constitute the exit face 2.

The first adhesive member (first medium) 32A has a refractive index n0 smaller than the refractive index n1, and the second adhesive member (second medium) 32B has a refractive index n1. That is, the refractive index of the first adhesive member 32A is smaller than the refractive index of the rod integrator 31, and the refractive index of the second adhesive member 32B is equal to the refractive index of the rod integrator 31. Here, the refractive index of the second adhesive member 32B and the refractive index of the rod integrator 31 include the case where the refractive index of the second adhesive member 32B is substantially equal to the refractive index of the rod integrator 31. . When the refractive index of the second adhesive member 32B is substantially equal to the refractive index of the rod integrator 31, the refractive index of the second adhesive member 32B is n _32B, and the refractive index of the rod integrator 31 is n ₃₁ . Then, the case where the refractive index of the second adhesive member 32B is in the range of n ₃₁ −0.01 <n _32B <n ₃₁ +0.01.

  The first adhesive member 32A and the second adhesive member 32B are, for example, translucent adhesives. Here, having translucency means having a property of transmitting light. Note that the first adhesive member 32A does not necessarily have translucency, and may be an adhesive having light absorption. The effect of using a light-absorbing adhesive will be described in a fourth embodiment described later.

  Here, the adhesive members 32A and 32B that join the first rod integrator 31A and the second rod integrator 31B are selectively used according to the position in the z direction of the optical element 30.

  Specifically, in the first region A1 from the incident surface 1 to the boundary portion 34 of the optical element 30, the first adhesive member 32A having a refractive index n0 smaller than the refractive index n1 of the rod integrator 31 is used. Yes. Here, the boundary portion 34 is a boundary between the first adhesive member 32A and the second adhesive member 32B, and is a portion where the first adhesive member 32A and the second adhesive member 32B are in contact with each other. On the other hand, a second adhesive member 32B having a refractive index n1 equal to the refractive index n1 of the rod integrator 31 is used in the second region A2 from the boundary 34 to the exit surface 2. Note that the position of the boundary 34 in the z direction can be arbitrarily set. The first region A1 is a region closer to the incident surface 1 than the boundary 34 in the z direction, and the second region A2 is a region closer to the exit surface 2 than the boundary 34 in the z direction. That is, the first adhesive member 32A is located on the incident surface 1 side with respect to the second adhesive member 32B, and the second adhesive member 32B is located on the emission surface 2 side with respect to the first adhesive member 32A. Yes.

  Thereby, in the first region A1 of the optical element 30, the refractive index n0 of the first adhesive member 32A is smaller than the refractive index n1 of the rod integrator 31, and therefore the physical relationship between the rod integrator 31 and the first adhesive member 32A. A typical boundary surface 33A (see FIG. 3) exists optically as an interface. Therefore, the light incident on the rod integrator 31 propagates in the z direction while being totally reflected at the interface (boundary surface 33A) between the rod integrator 31 and the first adhesive member 32A. More specifically, among the light incident on the rod integrator 31, the light propagating in the z direction while being totally reflected by the boundary surface 33A has the refractive index n1 of the rod integrator 31 and the refractive index n0 of the first adhesive member 32A. It is limited to light that satisfies the specified total reflection condition (critical angle that causes total reflection). When it can be considered that a substantial refractive index difference exists between the rod integrator 31 and the first adhesive member 32A (for example, a refractive index difference> 0.02), the critical angle with respect to the boundary surface 33A is sufficiently larger than 90 °. Therefore, most of the light incident on the rod integrator 31 is totally reflected at the boundary surface 33A.

  On the other hand, in the second region A2 of the optical element 30, the refractive index n1 of the second adhesive member 32B is equal to the refractive index n1 of the rod integrator 31, and thus the physical relationship between the rod integrator 31 and the second adhesive member 32B. The boundary surface 33B (see FIG. 3) does not exist optically as an interface and can be regarded as being integrated. More specifically, when it can be considered that there is no substantial refractive index difference between the rod integrator 31 and the first adhesive member 32A (for example, refractive index difference <0.02), the critical angle with respect to the boundary surface 33B is Since it approaches 90 degrees as much as possible, most of the light incident on the rod integrator 31 passes through the boundary surface 33B. Therefore, when the light propagating through the rod integrator 31 reaches the second region A2, there is no optical interface that can be a reflecting surface between the adjacent rod integrators 31A and 31B. Light propagates while being mixed with each other between the rod integrators 31A and 31B adjacent to each other via 32B. Of course, on the outermost surface 39 of the optical element 30 (see FIG. 1), the rod integrator 31 is in contact with air (the critical angle with respect to the outermost surface 39 is sufficiently smaller than 90 °). The light is totally reflected and propagates in the optical element 30 in the z direction.

  In other words, the optical element 30 changes the refractive index of the adhesive members 32A and 32B that are in contact with the rod integrator 31 before and after the boundary portion 34 so that it is not between the boundary portion 34 and the exit surface 2 (second region A2). In spite of using a plurality of rod integrators 31 arranged in parallel in the direction (x, y direction) orthogonal to the z direction, it can be considered that it is optically composed of one rod integrator. Therefore, two types of rod integrators with different cross-sectional dimensions (multiple rod integrators with a small cross-sectional shape and one rod integrator with a large cross-sectional shape) can be used in the z direction without changing the physical dimensions and materials of the rod integrator. An optically similar function can be realized with an optical element connected to the optical element.

  The light incident on the optical element 30 is incident on the incident surface 1 separately for each rod integrator 31, and is totally reflected by the boundary surface 33A between the rod integrator 31 and the first adhesive member 32A in each rod integrator 31. However, the intensity distribution is converted into uniform light while propagating in the z direction, and the adhesive member reaches the boundary 34 where the first adhesive member 32A changes to the second adhesive member 32B (arrayed rod integrators). 31) The process of homogenizing the intensity distribution within 31). Since there is no optical interface between the adjacent rod integrators 31 (between the rod integrator 31 and the second adhesive member 32B) between the boundary part 34 and the exit surface 2, the exit surface 2 is exposed from the boundary part 34. The light traveling to the side is mixed with each other between the adjacent rod integrators 31 and becomes light with a more uniform intensity distribution on the exit surface 2 of the optical element 30 (intensity in the optically integrated rod integrator 31). Distribution homogenization process).

  The optical element 30 has a function optically equivalent to an optical element configured by connecting a rod array in which a plurality of small diameter rod integrators are arranged in parallel and a single large diameter rod integrator. Since there is no connection between the rod array and the large-diameter rod integrator, light leakage due to imperfection of the connection does not occur. Therefore, according to the optical element 30 according to the present embodiment, illumination light with a uniform intensity distribution (illuminance distribution) can be obtained with high efficiency.

  The illumination device 100 and the optical element 30 according to the present embodiment have the following features, for example.

  According to the optical element 30, by having the first adhesive member 32A, the intensity distribution of the light incident from the incident surface 1 can be made uniform in each rod integrator, and the second adhesive member 32B is provided. Thus, the light uniformized in each rod integrator can be mixed and further uniformed. Thereby, the light with uniform intensity distribution can be obtained.

  Furthermore, according to the optical element 30, as described above, the optical element 30 is configured by one rod integrator in the optical axis L direction (z direction) from the incident surface 1 toward the exit surface 2. That is, there is no connection portion in the optical axis L direction (z direction). Therefore, light leakage due to imperfection of the connection portion does not occur. Therefore, illumination light with a uniform intensity distribution can be obtained with high efficiency.

  In the optical element 30, the first adhesive member 32 </ b> A and the second adhesive member 32 </ b> B function as a medium between the rod integrators 31 as described above. When the medium is not an adhesive member (for example, glass), for example, a member for joining the rod integrators 31 is required. According to the optical element 30, since the medium can also serve as an adhesive member, for example, a member for joining the rod integrators 31 becomes unnecessary.

  Since the illumination device 100 according to this embodiment includes the optical element 30 according to this embodiment, it is possible to obtain illumination light with a uniform intensity distribution with high efficiency.

1.2. Modified Example Next, a lighting device according to a modified example of the first embodiment will be described. Hereinafter, in the illuminating device according to the modification of the first embodiment, differences from the above-described example of the illuminating device 100 will be described, and the same points will be denoted by the same reference numerals and description thereof will be omitted.

(1) First Modification First, a first modification will be described. FIG. 4 is a schematic view of the optical element 301 of the illumination device according to this modification as viewed from the light source unit 10 side. FIG. 5 is a schematic view of the optical element 302 of the illumination device according to this modification as viewed from the light source unit 10 side.

  In the example of the illumination device 100, as shown in FIGS. 1 to 3, the shapes of the entrance end surface 3 and the exit end surface 4 of the rod integrator 31 are square, but the shapes of the entrance end surface 3 and the exit end surface 4 are particularly It is not limited, For example, a rectangle, a triangle, a circle, an ellipse etc. may be sufficient.

  In the optical element 301, as shown in FIG. 4, the shape of the incident end face 3 of the rod integrator 31 is a rectangle. Although not shown, the shape of the exit end face 4 of the rod integrator 31 is a rectangle like the entrance end face 3. That is, it can be said that the optical element 301 is configured by laminating the plate-shaped rod integrator 31 in the thickness direction. The incident surface 1 of the optical element 301 is composed of a plurality of rectangular incident end surfaces 3, and the shape thereof is a square.

  In the optical element 301, the number of rod integrators 31 in parallel in the x direction may be different from the number of rod integrators 31 in parallel in the y direction. In the illustrated example, the parallel number in the x direction is 1, and the parallel number in the y direction is 6. The optical element 301 only needs to be configured as an integrated optical element from the outside by the plurality of rod integrators 31 and the adhesive members 32A and 32B disposed in the gaps between the plurality of rod integrators 31. Since the parallel number of the rod integrators 31 in the x direction and the y direction is proportional to the uniformity of the illumination light, by adjusting the parallel number of the rod integrators 31 in the x direction and the y direction, illumination is performed in the x direction and the y direction. The degree of uniformity of the light intensity distribution can be controlled.

  Moreover, in the optical element 302, as shown in FIG. 5, the shape of the incident end surface 3 of the rod integrator 31 is a triangle. Although not shown, the shape of the exit end face 4 of the rod integrator 31 is a triangle like the entrance end face 3. The incident surface 1 of the optical element 302 is composed of a plurality of triangular incident end surfaces 3, and the shape thereof is a square.

  In the optical elements 301 and 302, the shape of the incident surface 1 is not limited to a square, and may be, for example, a rectangle or other polygons. Moreover, the shape of the emission surface 2 is not limited to a square, and may be, for example, a rectangle or other polygons.

(2) Second Modification Next, a second modification will be described. FIG. 6 is a schematic view of the optical element 303 of the illumination device according to this modification as viewed from the light source unit 10 side.

  In the example of the illumination device 100, as shown in FIGS. 1 to 3, the optical element 30 includes a plurality of rod integrators 31 having the same shape and the same size, but different shapes and different sizes. A plurality of rod integrators 31 having a thickness may be included.

  As shown in FIG. 6, the optical element 303 includes a rod integrator 31 and a rod integrator 31 </ b> S having different incident end surfaces 3. In the illustrated example, the rod integrator 31 having a large area of the incident end face 3 is arranged so as to surround the periphery of the rod integrator 31S having a small area of the incident end face 3.

  As described above, by changing at least one of the shape and size of the incident end surface 3 according to the position on the incident surface 1, the degree of uniformity of the intensity distribution of the illumination light can be controlled on the xy plane.

(3) Third Modification Next, a third modification will be described. FIG. 7 is a diagram schematically showing the optical element 304 of the illumination device according to this modification. FIG. 8 is a diagram schematically showing the optical element 305 of the illumination device according to this modification.

  In the example of the illumination device 100, the rod integrator 31 has a constant cross-sectional shape and dimensions without changing its cross-sectional shape and dimensions from the incident end face 3 toward the exit end face 4 along the z direction. The cross-sectional shape and dimensions may change from the incident end face 3 toward the exit end face 4.

  In the optical element 304, as shown in FIG. 7, a part or all of the rod integrators 31 have a tapered shape whose cross-sectional area increases from the incident end surface 3 toward the exit end surface 4. Here, the cross-sectional area of the rod integrator 31 is an area on a plane (xy plane) orthogonal to a direction (z direction) from the incident end face 3 toward the exit end face 4. Accordingly, the optical element 304 has a tapered shape in which the cross-sectional area gradually increases from the incident surface 1 toward the exit surface 2. In the illustrated example, the cross-sectional area of some rod integrators 31 gradually increases from the incident end surface 3 toward the exit end surface 4. For this reason, the cross-sectional area of the optical element 304 gradually increases from the incident surface 1 toward the exit surface 2.

  Further, in the optical element 305, as shown in FIG. 8, the rod integrator 31 has a tapered shape whose cross-sectional area increases from the incident end face 3 toward the exit end face 4. Specifically, the cross-sectional area of the rod integrator 31 increases from the incident end surface 3 toward the boundary portion 34, and has a certain size from the boundary portion 34 to the emission end surface 4. For this reason, the cross-sectional area of the optical element 305 increases from the incident surface 1 toward the boundary portion 34, and has a certain size from the boundary portion 34 to the exit surface 2.

  According to the optical elements 304 and 305, the rod integrator 31 has a tapered shape in which the cross-sectional area increases from the incident end surface 3 toward the exit end surface 4, so that the incident light has a boundary surface 33 </ b> A of the rod integrator 31. Since the angle of the light beam with respect to the optical axis L becomes smaller each time the light is reflected, the directivity of the illumination light can be improved. For example, in projectors, the angle range of light that can be modulated by a light modulator and the angle range of light that can be captured by a projection optical system are limited. Available. Therefore, when a lighting device including the optical elements 304 and 305 is used in a projector, light with a small light beam angle can be increased, and a bright projection image can be obtained with high light utilization efficiency.

  Further, according to the optical elements 304 and 305, the incident surface 1 side can be reduced in diameter and the exit surface 2 side can be increased in diameter. For example, when the illumination target 90 is larger than the light source unit 10, The generated light can be made uniform, and the illumination light can be efficiently supplied to the illumination object 90.

(4) Fourth Modification Next, a fourth modification will be described. FIG. 9 is a diagram schematically showing the optical element 306 of the illumination device according to this modification.

  In the example of the illumination device 100, the rod integrator 31 has a constant cross-sectional shape and dimensions without changing its cross-sectional shape and dimensions from the incident end face 3 toward the exit end face 4 along the z direction. The cross-sectional shape and dimensions may change from the incident end face 3 toward the exit end face 4.

  In the optical element 306, as shown in FIG. 9, a part or all of the rod integrators 31 have a tapered shape in which a cross-sectional area (area on the xy plane) decreases from the incident end face 3 toward the exit end face 4. . Therefore, the optical element 306 has a tapered shape in which the cross-sectional area gradually decreases from the incident surface 1 toward the exit surface 2. In the illustrated example, the cross-sectional area of some of the rod integrators 31 gradually decreases from the incident end face 3 toward the exit end face 4. For this reason, the cross-sectional area of the optical element 306 gradually decreases from the incident surface 1 toward the exit surface 2. Although not shown, the cross-sectional area of the rod integrator 31 decreases from the incident end surface 3 toward the boundary portion 34, and the boundary portion 34 to the emission end surface 4 may have a certain size.

  According to the optical element 306, since the exit surface 2 side can be reduced in diameter with respect to the entrance surface 1 side, the light beam cross section of the illumination light can be reduced with respect to the incident light. Therefore, for example, when the illumination target 90 is smaller than the light source unit 10, the light generated by the light source unit 10 can be efficiently irradiated onto the illumination target 90.

(5) Fifth Modification Next, a fifth modification will be described.

  In the example of the lighting device 100, the first adhesive member 32A having the refractive index n0 and the second adhesive member 32B having the refractive index n1 are used. However, the medium (first medium) having the refractive index n0 and the refractive index n1 are used. If it is a medium (2nd medium) which has this, it will not be limited to this. Examples of such a medium include glass and resin in addition to the above-described adhesive members 32A and 32B. In addition, when using glass as a medium, you may join by the interface joining which joins the interfaces of the adjacent rod integrator 31 directly, without using an adhesive member. Further, for example, air may be used as a medium (first medium) having a refractive index n0. In this case, a medium having a refractive index n1 between the rod integrators 31 adjacent between the entrance surface 1 and the boundary portion 34 and a refractive index n1 between the rod integrators 31 adjacent between the boundary portion 34 and the exit surface 2 (first 2 medium), and the optical element is integrated by this medium (second medium).

  Further, for example, the first medium and the second medium may be composed of different members, or may be configured integrally. For example, the first medium and the second medium may be integrally formed optical members. Thereby, a manufacturing process can be simplified. Examples of such an optical member include glass and resin including a region having a refractive index n0 and a region having a refractive index n1.

2. Second Embodiment 2.1. Next, the configuration of the illumination device according to the second embodiment will be described with reference to the drawings. FIG. 10 is a diagram schematically illustrating the optical element 307 of the illumination apparatus according to the second embodiment. In FIG. 10, the shade of the color of the first adhesive member 32A indicates the refractive index, and the darker the color, the smaller the refractive index. FIG. 10 corresponds to FIG. Hereinafter, in the illuminating device according to the second embodiment, points different from the example of the illuminating device 100 described above will be described.

  In the optical element 307, as shown in FIG. 10, the refractive index of the first adhesive member 32A changes from the incident surface 1 side toward the emission surface 2 side. In the illustrated example, the refractive index of the first adhesive member 32A continuously increases from the incident surface 1 side toward the exit surface 2 side. The boundary 34 is set in the vicinity of the exit surface 2, and the refractive index continuously changes from the entrance surface 1 to the exit surface 2 by the first adhesive member 32A and the second adhesive member 32B. ing. However, the second adhesive member 32B located between the boundary portion 34 and the exit surface 2 takes a constant refractive index regardless of the position in the z direction.

  For example, an adhesive having fluidity is used as an adhesive member before curing, an adhesive having a refractive index lower than the refractive index n1 is injected from the incident surface 1 side, and a refractive index n1 is provided from the exit surface 2 side. Since these adhesives are mixed by injecting the adhesive, after the curing, the first adhesive member 32A whose refractive index continuously changes from the incident surface 1 side to the exit surface 2 side is obtained. .

  For example, the first adhesive member 32A may be obtained using a plurality of adhesives having different refractive indexes.

  According to the optical element 307, as the refractive index of the first adhesive member 32A approaches the refractive index n1 of the rod integrator 31, light propagates while admixing gradually between the adjacent rod integrators 31, so the optical element 307 Illumination light having a more uniform intensity distribution (illuminance distribution) can be obtained on the exit surface 2. Further, since there is no boundary surface (a boundary surface where the refractive index changes discretely) between the adhesive members 32A and 32B and there is no light reflection at the boundary surface, light can be guided with high efficiency.

  Further, when polarized light is incident on the rod integrator, the polarization state is affected by total reflection (for example, linearly polarized light is elliptically knitted), but at the boundary surface between the first adhesive member 32A and the rod integrator 31. Since the refractive index difference is gradually reduced, the influence of the polarization state can be reduced, and the intensity distribution (illuminance distribution) can be made uniform while maintaining the polarization state at a high rate.

2.2. Modified Example Next, an illumination device according to a modified example of the second embodiment will be described. FIG. 11 is a diagram schematically showing an optical element 308 according to this modification. In FIG. 11, the shade of color of the first adhesive member 32A indicates the refractive index, and the darker the color, the smaller the refractive index. Hereinafter, in the illuminating device and the optical element 308 according to the modified example of the second embodiment, differences from the above-described examples of the illuminating device 100 and the optical element 307 will be described, and similar points will be described with the same reference numerals. Is omitted.

  In the example of the optical element 307, as shown in FIG. 10, the refractive index of the first adhesive member 32A continuously changed from the incident surface 1 side to the exit surface 2 side. The distribution of the member 32A is not particularly limited as long as the refractive index of the member 32A is smaller than the refractive index of the rod integrator 31.

  In the optical element 308, as shown in FIG. 11, the first adhesive member 32A has a constant refractive index on the incident surface 1 side, and the refractive index gradually changes (becomes larger) in the vicinity of the boundary 34. The refractive index is the same as that of the second adhesive member 32B.

  Even in such a case, the same effect as the optical element 307 described above can be obtained.

3. Third Embodiment Next, a configuration of a lighting apparatus according to a third embodiment will be described with reference to the drawings. FIG. 12 is a diagram schematically illustrating an optical element 309 of the illumination device according to the third embodiment. Hereinafter, in the illuminating device according to the third embodiment, points different from the example of the illuminating device 100 described above will be described, and description of similar points will be omitted.

  In the optical element 309, in addition to the first adhesive member 32A and the second adhesive member 32B, the optical element 309 is further sandwiched between the rod integrators 31 and between the first adhesive member 32A and the second adhesive member 32B. Further included are a third adhesive member 32C and a fourth adhesive member 32D. Further, the third adhesive member 32C is located closer to the first adhesive member 32A than the fourth adhesive member 32D, and the fourth adhesive member 32D is second than the third adhesive member 32C. It is located on the adhesive member 32B side. That is, in the optical element 309, the first adhesive member 32A, the third adhesive member 32C, the fourth adhesive member 32D, and the second adhesive member 32B are arranged in this order along the z direction from the incident surface 1 side. Yes.

  The refractive index of the third adhesive member 32C is equal to the refractive index of the rod integrator 31. That is, the third adhesive member 32C has the same refractive index n1 as the refractive index of the second adhesive member 32B.

  The refractive index of the fourth adhesive member 32 </ b> D is smaller than the refractive index of the rod integrator 31. For example, the fourth adhesive member 32D has the same refractive index n0 as the first adhesive member 32A. The refractive index of the fourth adhesive member 32D is not particularly limited as long as it is smaller than the refractive index of the rod integrator 31, and may have a refractive index different from that of the first adhesive member 32A.

  The optical element 309 can be said to be a multi-stage (two stages in the illustrated example) of the optical element 30 shown in FIGS. Here, the optical element 30 has two stages, but the number of stages is not particularly limited, and may be three or more.

  According to the optical element 309, by providing the adhesive members 32A, 32B, 32C, and 32D, the process of homogenizing the intensity distribution in each arrayed rod integrator 31 and the optically integrated rod integrator 31 are provided. There can be a plurality (two times in the illustrated example) of the intensity distribution homogenization process. Therefore, illumination light with a more uniform intensity distribution can be obtained on the exit surface 2 of the optical element 309.

  Furthermore, according to the optical element 309, since there is no connection portion in the z direction from the incident surface 1 to the exit surface 2, light leakage due to imperfection of the connection portion does not occur. Therefore, illumination light with a uniform intensity distribution can be obtained with high efficiency.

4). 4th Embodiment Next, the structure of the illuminating device which concerns on 4th Embodiment is demonstrated, referring drawings. FIG. 13 is a schematic diagram illustrating a configuration of an illumination device 200 according to the fourth embodiment. Hereinafter, in the illuminating device 200 which concerns on 4th Embodiment, a different point from the example of the illuminating device 100 mentioned above is demonstrated, the same code | symbol is attached | subjected about the same point, and description is abbreviate | omitted.

  In the example of the illumination device 100, the light source unit 10 has one light emitting element 11 as illustrated in FIG. 1. On the other hand, in the lighting device 200, the light source unit 10 has a plurality of light emitting elements 11. Specifically, in the lighting device 200, one light emitting element 11 is provided for one rod integrator 31, and the light generated by one light emitting element 11 is incident on the incident end face of one corresponding rod integrator 31. 3 so as to be incident on 3. Thereby, illumination light with a large light intensity can be obtained. Moreover, since the intensity | strength of the light which injects into each rod integrator 31 can be equalized compared with the case where light injects from a single light source, the illumination light with which intensity | strength distribution was made more uniform can be obtained. In addition, when the light incident on the optical element 30 is polarized light, the light is incident only on the rod integrator 31 from the viewpoint of maintaining the degree of polarization, or adjacent to the boundary 34 from the incident surface 1. As a medium (first medium) disposed between the rod integrators 31, it is desirable to use a medium having a light absorption property. When light is incident on a translucent medium disposed between adjacent rod integrators 31, the light may decrease the degree of polarization while traveling in the z direction and may enter the rod integrator 31. Therefore, the degree of polarization of the light emitted from the optical element 30 can be maintained at a high level by absorbing the light having a lowered degree of polarization using a light-absorbing medium.

5. Fifth Embodiment Next, a projector according to a fifth embodiment will be described with reference to the drawings. FIG. 14 is a diagram schematically showing a projector 1000 according to the fifth embodiment. In FIG. 14, for convenience, illustration of a housing that constitutes the projector 1000 is omitted.

  In the projector 1000, a red light source (illumination device) 200R that emits red light, green light, and blue light, a green light source (illumination device) 200G, and a blue light source (illumination device) 200B are an illumination device (for example, an illumination device) according to the present invention. 200).

  The projector 1000 includes transmissive liquid crystal light valves (light modulation devices) 1010R, 1010G, and 1010B that modulate light emitted from the light sources 200R, 200G, and 200B according to image information, and liquid crystal light valves 1010R, 1010G, and 1010B. A projection lens (projection device) 1030 that magnifies and projects the image formed by the projection onto a screen (display surface). In addition, the projector 1000 can include a cross dichroic prism (color light combining unit) 1020 that combines the light emitted from the liquid crystal light valves 1010R, 1010G, and 1010B and guides the light to the projection lens 1030.

  The three color lights modulated by the liquid crystal light valves 1010R, 1010G, and 1010B are incident on the cross dichroic prism 1020. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are arranged in a cross shape on the inner surface thereof. These dielectric multilayer films combine the three color lights to form light representing a color image. Then, the synthesized light is projected on a screen by a projection lens 1030 which is a projection optical system, and an enlarged image is displayed.

  According to the projector 1000, as described above, the illumination device 200 that can obtain illumination light with uniform intensity distribution (illuminance distribution) with high efficiency can be used as a light source. Therefore, the projector 1000 can project a bright image with little illuminance unevenness.

  In the above example, a transmissive liquid crystal light valve is used as the light modulation device. However, a light valve other than liquid crystal may be used, or a reflective light valve may be used. Examples of such a light valve include a reflective liquid crystal light valve and a digital micromirror device in which a large number of micromirrors are arranged in a matrix. Further, the configuration of the projection optical system is appropriately changed depending on the type of light valve used.

  In addition, embodiment mentioned above and a modification are examples, Comprising: It is not necessarily limited to these. For example, a plurality of embodiments and modifications can be combined as appropriate.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

A1 first region, A2 second region, 1 entrance surface, 2 exit surface,
3, 3a, 3b entrance end face, 4, 4a, 4b exit end face, 5 connection face, 10 light source part,
11 Light emitting element, 12 Light distribution angle control element, 20 Light condensing element, 30 Optical element,
31, 31A, 31B Rod integrator, 32A First adhesive member,
32B second adhesive member, 33A interface, 33B interface, 34 interface,
39 outermost surface, 90 lighting object, 100, 200 lighting device,
301, 302, 303, 304, 305, 306, 307, 308, 309 optical element, 1000 projector,
1010R, 1010G, 1010B liquid crystal light valve (light modulation device),
1020 Cross dichroic prism, 1030 Projection lens (projection device)

Claims (10)

An optical element having a first surface and a second surface facing each other,
A first rod integrator having a first end face and a second end face;
A second rod integrator having a third end face and a fourth end face;
A first medium and a second medium sandwiched between the first rod integrator and the second rod integrator;
Including
The first end surface and the third end surface constitute the first surface,
The second end surface and the fourth end surface constitute the second surface,
The first medium is located closer to the first surface than the second medium;
The second medium is located closer to the second surface than the first medium;
The refractive index of the first medium is smaller than the refractive index of the first rod integrator and the refractive index of the second rod integrator,
The optical element, wherein the refractive index of the second medium is equal to the refractive index of the first rod integrator and the refractive index of the second rod integrator.   The optical element according to claim 1, wherein the first medium and the second medium are adhesive members that join the first rod integrator and the second rod integrator.   The optical element according to claim 1, wherein the first medium and the second medium are integrally formed optical members. A third medium and a fourth medium sandwiched between the first rod integrator and the second rod integrator and located between the first medium and the second medium;
The third medium is located closer to the first medium than the fourth medium;
The fourth medium is located closer to the second medium than the third medium;
The refractive index of the third medium is equal to the refractive index of the first rod integrator and the refractive index of the second rod integrator,
4. The optical element according to claim 1, wherein a refractive index of the fourth medium is smaller than a refractive index of the first rod integrator and a refractive index of the second rod integrator. 5. . The refractive index of the first medium, the increases in accordance with a first surface toward the second surface side, the optical element according to any one of claims 1 to 3, characterized in that.   The cross section of the first rod integrator and the second rod integrator gradually increases from the first surface toward the second surface, according to any one of claims 1 to 5. Optical element.   6. The first rod integrator and the second rod integrator each have a gradually decreasing cross-sectional area from the first surface toward the second surface. 6. Optical element. An optical element according to any one of claims 1 to 7,
A light source unit for generating light incident on the first surface of the optical element;
A lighting device comprising: The light source unit is
A first light emitting element for generating light incident on the first end face of the first rod integrator;
A second light emitting element for generating light incident on the third end face of the second rod integrator;
The lighting device according to claim 8, comprising: The lighting device according to claim 8 or 9,
A light modulation device that modulates light emitted from the second surface of the illumination device according to image information;
A projection device for projecting an image formed by the light modulation device;
Including a projector.