JP6427856B2 - Microlens element, light modulation device and projector - Google Patents

Description

  The present invention relates to a microlens element, a light modulation device, and a projector.

  In recent years, it has been studied to use a laser light source as a light source of a projector for the purpose of increasing the brightness of an image. However, since the light emitted from the laser light source has coherence, speckle noise is generated and display quality is deteriorated. Speckle noise is noise generated when light emitted from the projection optical system is scattered on the projection surface and the scattered light interferes.

  As means for reducing this kind of speckle noise, there has been disclosed a projection-type image display apparatus provided with a diffusion optical element for uniformizing the spatial distribution of light intensity on the exit pupil plane of the projection optical system (see below). Patent Document 1). Also, a projector that reduces speckle noise by forming a diffractive optical element or a light diffusion layer on a thin film transistor (hereinafter abbreviated as TFT) array substrate constituting a liquid crystal light valve and diffusing transmitted light. Is disclosed (see Patent Document 2 below).

  On the other hand, in a microlens array arranged facing a liquid crystal panel, a projector device is disclosed in which a plurality of types of microlenses having different radii of curvature are periodically arranged for the purpose of reducing depolarization and ensuring light use efficiency. (See Patent Document 3 below).

JP 2011-180281 A JP 2010-39137 A JP 2005-352392 A

  In projectors that use a solid-state light source such as a laser light source, reduction of speckle noise is an issue, but in addition to this, it is required to improve light utilization efficiency by reducing, for example, vignetting in the projection optical system. ing. However, the above-described prior art cannot satisfy this requirement.

  For example, in the projection display apparatus disclosed in Patent Document 1, it is necessary to dispose a diffusion optical element on the optical path in order to make the spatial distribution of light intensity uniform. In this case, the light utilization efficiency is reduced by adding the diffusing optical element. Similarly, in the projector of Patent Document 2, the light utilization efficiency is reduced by using a diffractive optical element or a light diffusion layer. Another problem is that a diffractive optical element and a light diffusion layer must be formed on the TFT substrate, which complicates the manufacturing process. The projector device of Patent Document 3 does not consider speckle noise at all, and cannot reduce speckle noise.

  One aspect of the present invention has been made to solve the above-described problem, and an object thereof is to provide a projector with low speckle noise and high light utilization efficiency. Another object is to provide a microlens element and a light modulation device suitable for use in this type of projector.

In order to achieve the above object, a microlens element according to a first aspect of the present invention is a microlens element provided in a light modulation element including a light modulation region including a plurality of pixels. A first microlens layer provided in a peripheral region of the first microlens layer; and a first microlens layer provided in a central region of the first microlens layer. Each of the first microlens and the second microlens is a plano-convex lens, and a part of the convex surface of the first microlens is a flat surface, first area of the flat surface of the microlens, the larger than the area of the flat region of the second microlenses, the first microlenses incident on the second microlens The uniformity of the angular distribution of the light emitted from the layer is higher than the uniformity of the angular distribution of the light incident on the first microlens and emitted from the first microlens layer. The central intensity of the light incident on the microlens and emitted from the first microlens layer is greater than the central intensity of the light incident on the second microlens and emitted from the first microlens layer. It is characterized by being expensive.

  In a projector, the illuminance (intensity) distribution at the exit pupil of the projection optical system affects the magnitude of speckle noise. In order to reduce speckle noise, it is effective to improve the uniformity of the illuminance distribution in the exit pupil. Further, the higher the uniformity of the angular distribution of light incident on the projection optical system, the higher the uniformity of the illuminance distribution at the exit pupil. Accordingly, when the microlens element of the first aspect of the present invention is used, the uniformity of the angular distribution of the light incident on the second microlens and emitted from the microlens element is incident on the first microlens. As a result, the uniformity of the angular distribution of the light emitted from the microlens element is higher than that in the central area of the microlens element, and the effect of reducing speckle noise is higher than the peripheral area of the microlens element.

  In the projector, a component having a large angle in the light traveling toward the projection optical system cannot be effectively used because it is lost by an optical element such as the projection optical system. However, when the microlens element of the first aspect of the present invention is used, the central intensity of the light incident on the first microlens and emitted from the microlens element is incident on the second microlens. Since it is higher than the central intensity of the light emitted from the lens element, the utilization efficiency of the light emitted from the peripheral area of the microlens element can be improved. As a result, it is possible to configure a light modulation device and a projector that have low speckle noise as a whole and high light utilization efficiency as a whole.

  In the microlens element according to the first aspect of the present invention, each of the first microlens and the second microlens is a plano-convex lens, and a part of the convex surface of the first microlens is a flat surface. There may be.

  According to the above configuration, for example, when parallel light is incident on the microlens element, the light incident on the first microlens from the flat surface is emitted as parallel light from the microlens element. Further, light that enters the first microlens from a convex surface other than a flat surface and exits from the microlens element is focused toward the focal point. As a result, for example, less light is emitted from the subsequent optical system such as a projection optical system, and the light utilization efficiency can be further improved. As a result, it is possible to configure a light modulation device and a projector that have low speckle noise as a whole and high light utilization efficiency as a whole.

  In the microlens element of the first aspect of the present invention, a part of the convex surface of the second microlens is a flat surface, and the area of the flat surface of the first microlens is the second microlens. It is good also as a structure larger than the area of the said flat surface.

  According to the above configuration, a part of the convex surface of the second microlens corresponding to the pixel in the central region of the light modulation region is also a flat surface. In this case, the light incident on the second microlens is also emitted as parallel light. However, since the area of the flat surface of the first microlens is larger than the area of the flat surface of the second microlens, the ratio of the light beam emitted as parallel light is second in the first microlens. More than a micro lens. Therefore, the second microlens is relatively larger than the first microlens for the effect of reducing speckle noise, and the first microlens is relative to the second microlens for the effect of improving the light utilization efficiency. Become bigger. As a result, it is possible to configure a light modulation device and a projector that have low speckle noise as a whole and high light utilization efficiency as a whole.

  In the microlens element according to the first aspect of the present invention, the refractive index of the first microlens may be smaller than the refractive index of the second microlens.

  According to said structure, the refractive index of the 2nd micro lens corresponding to the pixel of the center area | region of a light modulation area | region is relatively large. For this reason, the angle distribution of the light transmitted through the second microlens is widened, and the illuminance distribution at the pupil position becomes more uniform. As a result, speckle noise can be reduced. On the other hand, the refractive index of the first microlens corresponding to the pixels in the peripheral region of the light modulation region is relatively small. For this reason, the angular distribution of light transmitted through the first microlens is smaller than the angular distribution of light transmitted through the second microlens. As a result, for example, less light is emitted to the subsequent optical system such as a projection optical system, and the light use efficiency can be improved. As a result, it is possible to configure a light modulation device and a projector that have low speckle noise as a whole and high light utilization efficiency as a whole.

  The microlens element according to the first aspect of the present invention further includes a second microlens layer, and the refractive power of the second microlens layer in the peripheral region is determined by the second microlens layer in the central region. It is good also as a structure larger than the refractive power of this.

  According to the above configuration, for example, when parallel light is incident on the light modulation element, the parallel light is converted into light having a predetermined angular distribution by the first microlens layer on the light incident side, and is applied to the light modulation element. Incident light and further incident on the second microlens layer. Since the refractive power of the second microlens layer in the peripheral region is larger than the refractive power of the second microlens layer in the central region, the light incident on the peripheral region of the second microlens layer has an angular distribution again. It is converted into narrow light and emitted from the microlens element. For this reason, for example, the amount of light that is applied to the optical element at the subsequent stage such as a projection lens is reduced, and the light use efficiency can be improved. On the other hand, the angular distribution of the light emitted from the central region of the microlens element is wider and more uniform than the angular distribution emitted from the peripheral region of the microlens element. Therefore, a high speckle noise reduction effect can be obtained. As a result, it is possible to configure a light modulation device and a projector that have low speckle noise as a whole and high light utilization efficiency as a whole.

  In the microlens element according to the first aspect of the present invention, the second microlens layer may include a first convex lens provided in the peripheral region.

  According to said structure, the structure which makes the refractive power of the 2nd micro lens layer in a peripheral region larger than the refractive power of the 2nd micro lens layer in a center region by the 1st convex lens provided in the peripheral region. Can be realized.

  In the microlens element according to the first aspect of the present invention, the second microlens layer further includes a second convex lens provided in the central region, and the refractive power of the second convex lens is the first convex lens. It is good also as a structure smaller than the refractive power of a convex lens.

  According to this configuration, since the second microlens layer includes the second convex lens provided in the central region, the light modulation region is compared with the case where the second microlens layer not including the second convex lens is used. The light emitted from the central region of the light also has an effect of being converted into light having a narrow angular distribution. Even in that case, since the refractive power of the second convex lens is smaller than the refractive power of the first convex lens, the light incident on the peripheral region of the second microlens layer has an angular distribution compared to the light incident on the central region. Is converted into narrower light.

  In the microlens element according to the first aspect of the present invention, the second microlens layer may include a concave lens provided in the central region.

  According to this configuration, the second microlens layer includes a concave lens provided in the central region, and light emitted from the central region is converted into light having a larger angular distribution by the action of the concave lens. Therefore, speckle noise can be reduced more effectively. On the other hand, the light emitted from the peripheral region does not enter the concave lens, and thus is not converted into light having a larger angular distribution. For this reason, for example, the amount of light that is applied to the subsequent optical system such as the projection optical system does not increase. In this way, speckle noise can be reduced and light utilization efficiency can be improved.

  A light modulation device according to a first aspect of the present invention includes a light modulation element including a light modulation region including a plurality of pixels, and a microlens element, and the microlens element is one aspect of the present invention. It is a microlens element.

  According to this configuration, since the light modulation device according to the first aspect of the present invention includes the microlens element according to one aspect of the present invention, speckle noise can be reduced and light utilization efficiency can be improved. be able to.

  In the light modulation device according to the first aspect of the present invention, the microlens element is a microlens element including a first microlens layer, and the microlens element is provided on a light incident side of the light modulation element. It is desirable that

  According to this configuration, light can be efficiently incident on each pixel of the light modulation element by the first microlens layer, and light utilization efficiency can be improved.

  In the light modulation device according to the first aspect of the present invention, the microlens element is a microlens element including a first microlens layer and a second microlens layer, and the first microlens layer is It is desirable that the light modulation element is provided on the light incident side, and the second microlens layer is provided on the light emission side of the light modulation element.

  According to this configuration, as the first microlens layer, for example, the same convex lens can be used in the central region and the peripheral region, and light can be efficiently incident on each pixel of the light modulation element. Efficiency can be improved.

  A projector according to an aspect of the present invention includes a light source device, a light modulation device that modulates light from the light source device, and a projection optical system that projects light modulated by the light modulation device. The modulation device is the light modulation device according to one aspect of the present invention.

  Since the projector according to one aspect of the present invention includes the light modulation device according to one aspect of the present invention, a projector having excellent display quality and high light utilization efficiency can be realized.

1 is a schematic diagram illustrating a configuration of a projector according to a first embodiment of the invention. It is a perspective view which shows the micro lens element used for the projector of 1st Embodiment. It is a top view of a micro lens element. It is a figure for demonstrating the effect | action of a micro lens element. It is a figure which shows the simulation result of the angular distribution of the emitted light from (A)-(C) liquid crystal light valve. It is a perspective view which shows the micro lens element of 2nd Embodiment. It is a top view of a micro lens element. It is a perspective view which shows the micro lens element of 3rd Embodiment. It is a top view of a micro lens element. It is a figure which shows the simulation result of the angular distribution of the emitted light from (A)-(C) liquid crystal light valve. It is a perspective view which shows the micro lens element of 4th Embodiment. It is a perspective view which shows the modification of the micro lens which comprises a micro lens element. It is a schematic diagram which shows the microlens of FIG. It is sectional drawing which shows the light modulation apparatus of 5th Embodiment. It is sectional drawing which shows the light modulation apparatus of the modification of 5th Embodiment. It is sectional drawing which shows the light modulation apparatus of 6th Embodiment. It is a top view which shows the modification of a micro lens element. It is a top view which shows the other modification of a micro lens element.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
The projector according to the present embodiment is a liquid crystal projector using a laser light source.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.

  As shown in FIG. 1, the projector 1 according to the first embodiment includes a light source device 2R that emits red light, a light source device 2G that emits green light, a light source device 2B that emits blue light, and a light modulation device for red light. 3R, a green light modulation device 3G, a blue light modulation device 3B, a color synthesis element 4, and a projection optical system 5. That is, the projector 1 includes a set of a light source device and a light modulation device for each color light of red (R), green (G), and blue (B), and a total of three sets. In this specification, the light modulator 3R for red light, the light modulator 3G for green light, and the light modulator 3B for blue light may be referred to as the light modulator 3.

The projector 1 generally operates as follows.
The color light emitted from each of the light source device 2R, the light source device 2G, and the light source device 2B is incident on the red light modulation device 3R, the green light modulation device 3G, and the blue light modulation device 3B corresponding to each color light. Then modulated. The color lights modulated by the red light modulation device 3R, the green light modulation device 3G, and the blue light modulation device 3B are incident on the color synthesis element 4 and synthesized. The light containing the image synthesized by the color synthesizing element 4 is enlarged and projected onto the projection surface 6 such as a wall or a screen by the projection optical system 5, and a full-color projection image is displayed.

Hereinafter, each component of the projector 1 will be described.
Each of the light source device 2R, the light source device 2G, and the light source device 2B includes a red light source unit 7R, a green light source unit 7G, and a blue light source unit 7B that emit corresponding color light, and a computer generated hologram 8 (Computer Generated Hologram, hereinafter referred to as CGH). Abbreviated) and a collimating lens 9. Each of the red light source unit 7R, the green light source unit 7G, and the blue light source unit 7B has a plurality of laser light sources (not shown) and emits laser light that is coherent light. In the red light source unit 7R, the green light source unit 7G, and the blue light source unit 7B, for example, by arranging a plurality of laser light sources in an array, high output laser light can be obtained. The red light source unit 7R includes a plurality of red laser light sources that emit red light. The green light source unit 7G includes a plurality of green laser light sources that emit green light. The blue light source unit 7B has a plurality of blue laser light sources that emit blue light.

  The CGH 8 is a diffractive optical element in which a different diffraction pattern is formed for each region. The CGH 8 forms a beam so that the illumination area of the light emitted from the CGH 8 matches each of the light modulation areas of the red light modulation device 3R, the green light modulation device 3G, and the blue light modulation device 3B. To do. The collimating lens 9 collimates the laser light emitted from each of the red light source unit 7R, the green light source unit 7G, and the blue light source unit 7B, and the red light light modulation device 3R, the green light light modulation device 3G, and the blue light. The light is emitted toward the light modulator 3B.

  The light modulation device includes a red light light modulation device 3R, a green light light modulation device 3G, and a blue light light modulation device 3B. The red light modulation device 3R, the green light modulation device 3G, and the blue light modulation device 3B have the same configuration. Each of the light modulator 3R for red light, the light modulator 3G for green light, and the light modulator 3B for blue light includes an incident-side polarizing plate (not shown), a first microlens layer 11, and a liquid crystal light valve 12. And an exit side polarizing plate (not shown). The liquid crystal light valve 12 has a plurality of pixels arranged in a matrix, and the formation region of the plurality of pixels is a light modulation region. The first microlens layer 11 is disposed on the light incident side of the liquid crystal light valve 12. The first microlens layer 11 may be disposed in close contact with the light incident side surface of the liquid crystal light valve 12 or may be disposed apart from the light incident side surface of the liquid crystal light valve 12. Good. Although a well-known polarizing plate can be used for the incident side polarizing plate and the emitting side polarizing plate, for example, it is desirable to use an inorganic polarizing plate having high heat resistance. The first microlens layer 11 of the present embodiment corresponds to a microlens element in the claims, and the liquid crystal light valve 12 corresponds to a light modulation element in the claims.

  Hereinafter, for convenience of description, the peripheral region of the light modulation region and the peripheral region of the first microlens layer 11 are defined as the first region, the central region of the light modulation region and the center of the first microlens layer 11 are defined. The region may be referred to as a second region. In addition, a region between the first region and the second region may be referred to as a third region. In plan view, the peripheral region of the light modulation region and the peripheral region of the first microlens layer 11 overlap each other, and the central region of the light modulation region and the central region of the first microlens layer 11 mutually overlap. It shall overlap.

  As shown in FIG. 2, the liquid crystal light valve 12 has a TFT array substrate 14 on which a thin film transistor (hereinafter abbreviated as TFT) is formed for each pixel, a counter substrate 15, and a TFT array substrate 14. A liquid crystal layer 16 sandwiched between the substrate 15 and the substrate 15. The liquid crystal light valve 12 is composed of a transmissive liquid crystal panel. The liquid crystal light valve 12 is electrically connected to a signal source (not shown) such as a personal computer that supplies image signals. The liquid crystal light valve 12 modulates incident light for each pixel based on the image signal to form an image. The red light modulation device 3R, the green light modulation device 3G, and the blue light modulation device 3B form a red image, a green image, and a blue image, respectively. The color light modulated by each of the red light modulation device 3R, the green light modulation device 3G, and the blue light modulation device 3B is incident on the color composition element 4.

  As shown in FIG. 2, the first microlens layer 11 has a plurality of microlenses arranged in an array. Here, the liquid crystal light valve 12 has a plurality of pixels arranged in 6 rows and 6 columns, and the first microlens layer 11 has a plurality of microlenses arranged in 6 rows and 6 columns. . Each of the plurality of microlenses is arranged corresponding to the pixel position of the liquid crystal light valve 12. The plurality of microlenses are provided in the plurality of first microlenses 18 provided in the first region, the plurality of second microlenses 19 provided in the second region, and the third region. A plurality of third microlenses 20. Each of the first microlens 18, the second microlens 19, and the third microlens 20 is a plano-convex lens.

  The first microlens 18 has a truncated cone shape. Therefore, a central portion that is a part of the convex surface 18 a of the first microlens 18 is a flat surface 18 c that is substantially parallel to the flat surface 18 b of the first microlens 18. The third microlens 20 has a truncated cone shape. Therefore, a central portion that is a part of the convex surface 20 a of the third microlens 20 is a flat surface 20 c that is substantially parallel to the flat surface 20 b of the third microlens 20. The second microlens 19 has a conical shape. The convex surface 19 a of the second microlens 19 is an inclined surface that is inclined with respect to the flat surface 19 b of the second microlens 19.

  In the example of the present embodiment, as shown in FIG. 3, the first microlens 18 is arranged in the outermost first row and the outermost first column. The third microlens 20 is arranged in the second row from the outside and the second column from the outside. The second microlenses 19 are arranged in the middle 2 rows and 2 columns.

  In the following description, of the two parallel surfaces of the truncated cone forming the shape of the first microlens 18 and the third microlens 20, the surface having the smaller area is referred to as the upper surface, and the surface having the larger area is referred to as the upper surface. The surface is referred to as a lower surface, and the surface inclined with respect to the upper surface and the lower surface is referred to as an inclined surface. Further, the bottom surface of the cone forming the shape of the second microlens 19 is referred to as a lower surface, and the surface inclined with respect to the lower surface is referred to as an inclined surface.

  In all of the first microlens 18, the second microlens 19, and the third microlens 20, the inclination angle of the inclined surface with respect to the lower surface is the same. In other words, the first microlens 18 and the third microlens 20 have the shape of a truncated cone when the cone, which is the shape of the second microlens 19, is cut by a plane parallel to the lower surface (plane 19b). Have. Further, when comparing the first microlens 18 and the third microlens 20 both having a truncated cone shape, the area of the upper surface (flat surface 18c) of the first microlens 18 is the third microlens. It is larger than the area of the upper surface of 20 (flat surface 20c).

  The apex of the second microlens 19 is sharp, and the second microlens 19 does not have a flat surface. However, if the shape of the second microlens 19 is regarded as a truncated cone having an upper surface (flat surface) area of 0 (zero), the first microlens 18, the second microlens 19, and the third microlens. In other words, the area of the upper surface of 20 increases in the order of the second region, the third region, and the first region from the center to the periphery of the microlens element.

  When realizing this configuration, the first microlens 18, the second microlens 19, and the third microlens 20 have the same diameter on the bottom surface, and the height from the bottom surface to the top surface or the top is the second microlens. You may make it low toward the periphery from the center of the 1st micro lens layer 11 in order of a field, the 3rd field, and the 1st field. Alternatively, the height from the lower surface to the upper surface or the vertex is made the same, and the diameter of the lower surface is directed from the center to the periphery of the first microlens layer 11 in the order of the second region, the third region, and the first region. You can make it bigger.

  Returning to FIG. 1, the color synthesizing element 4 includes a dichroic prism or the like. The dichroic prism has a configuration in which four triangular prisms are bonded to each other. The surface on which the triangular prisms are bonded together is the inner surface of the dichroic prism. On the inner surface of the dichroic prism, a mirror surface that reflects red light and transmits green light and a mirror surface that reflects blue light and transmits green light are provided orthogonal to each other. The green light incident on the dichroic prism passes through the mirror surface and goes straight and is emitted. The red light and blue light incident on the dichroic prism are selectively reflected or transmitted by the mirror surface and emitted in the same direction as the emission direction of the green light.

In this way, the three color lights LR, color light LG, and color light LB containing the image information are superimposed and synthesized. The synthesized light is enlarged and projected onto the projection surface 6 by the projection optical system 5, and an image is formed on the projection surface 6.
The projector 1 according to the present embodiment has the above configuration.

Hereinafter, the operation of the first microlens layer 11 of the present embodiment will be described.
FIG. 4 is a schematic diagram in which the first microlens 18 in the peripheral region and the second microlens 19 in the central region are extracted from the first microlens layer 11. A plane including the plane 18b of the first microlens 18 and the plane 19b of the second microlens 19 is defined as a reference plane F. Here, the light L0 incident on the first microlens layer 11 from the upper surface side of the first microlens layer 11 perpendicular to the reference plane F will be considered.

First, the effect of reducing speckle noise will be described.
As the angular distribution of the light emitted from the light modulation device 3 spreads widely and the angle dependence of the light intensity in the angle range where the light spreads is small, the speckle contrast is lowered and the flickering on the screen is reduced. Less. As described below, the effect of reducing speckle noise varies depending on the shape of the microlens.

  The first microlens 18 has a truncated cone shape, and the flat surface 18c among the surfaces on which the light L0 is incident is a plane perpendicular to the central axis of the light L0. Therefore, out of the light incident on the first microlens 18, the light L0 incident on the inclined surface is refracted and emitted from the first microlens 18, but the light L0 incident on the flat surface 18c goes straight as it is. And emitted from the first microlens 18. As described above, the first microlens 18 has a function of emitting a part of the incident light L0 without diffusing.

  On the other hand, the second microlens 19 has a conical shape, and all of the surfaces on which the light L0 is incident are inclined surfaces. Therefore, almost all components of the light L0 incident on the second microlens 19 are refracted and emitted from the second microlens 19. That is, the second microlens 19 has an action of diffusing more light than the first microlens 18.

  The present inventors performed a simulation to investigate the relationship between the effect of reducing speckle noise and the shape of the microlens. In the simulation, when light L0 having a predetermined angular distribution is incident on the first microlens layer 11 from the upper surface side of the first microlens layer 11 perpendicularly to the reference plane F, the light L0 is emitted from the microlens. The angular distribution of the emitted light was obtained. Furthermore, the uniformity of the angle distribution and the center intensity were calculated from the obtained angle distribution. As the light L0 incident on the microlens, a portion having a high intensity and a portion having a low intensity are alternately arranged, and light having a checkered flag-like angle distribution pattern as a whole is used.

  FIG. 5A, FIG. 5B, and FIG. 5C are diagrams showing the angular distribution of the intensity of light emitted from one microlens. The horizontal and vertical axes of the angle distribution diagram are the emission angles in two directions perpendicular to the optical axis and perpendicular to each other. In the angle distribution diagram, a portion that appears white indicates a portion with high strength, and a portion that appears black indicates a portion with low strength.

  FIG. 5A is an angle distribution diagram of the second microlens 19. FIG. 5B is an angle distribution diagram of the third microlens 20. FIG. 5C is an angle distribution diagram of the first microlens 18. The simulation conditions were such that the height from the lower surface to the upper surface of each microlens was the same at 6 μm, and the inclination angle of the inclined surface was the same. For the second microlens 19, the upper surface diameter was 0 (conical shape without the upper surface), and the lower surface diameter was 16.4 μm. For the third microlens 20, the upper surface diameter was 4 μm and the lower surface diameter was 20.4 μm. For the first microlens 18, the upper surface diameter was 6 μm and the lower surface diameter was 22.4 μm.

  [Table 1] shows the dimensions of the above parts, the uniformity of the angular distribution, and the center strength. The uniformity of the angular distribution is shown as a relative value when the uniformity of the angular distribution of the second microlens is 1. The center intensity indicates the ratio of the amount of light that falls within a rectangular angle range within 5 degrees from the center (0, 0) in the angle distribution diagram.

  As shown in FIG. 5, since the inclination angles of the inclined surfaces of the microlenses are the same, the spread of the angle distribution of the emitted light (the spread angle of the light bundle) is substantially the same. However, as can be seen from FIG. 5 and Table 1, in the case of the second microlens 19 having no upper surface (flat surface), the uniformity of angular distribution is relatively high and the area of the upper surface (flat surface) is large. In the case of one microlens 18, the uniformity of the angular distribution is relatively low. High uniformity of the angular distribution means that the angle dependency of the light intensity is small in the angle range where the light spreads. Thus, the second microlens 19 has a higher angular distribution uniformity than the first microlens 18 and has a high speckle noise reduction effect.

Next, the effect of improving the light use efficiency will be described.
Of the light emitted from the light modulation device 3, the component having a large emission angle is generated by the projection optical system 5 and cannot be used. As can be seen from Table 1, the first microlens 18 has a higher center intensity of emitted light than the second microlens 19, that is, has fewer components with a large emission angle. Therefore, the first microlens 18 has a higher effect of improving the light utilization efficiency than the second microlens 19. The third microlens has intermediate characteristics between the second microlens and the first microlens.

  As described above, the second microlens 19 has a higher speckle noise reduction effect than the first microlens 18, and the first microlens 18 uses light more than the second microlens 19. High efficiency improvement effect. Here, in order to reduce speckle noise in the image projected on the projection surface 6, it is conceivable to provide the second microlens 19 in all the pixels of the light modulation device 3. However, the decrease in the light use efficiency caused by the projection optical system 5 is remarkable in the peripheral region. Therefore, when the second microlenses 19 are provided in all the pixels of the light modulation device 3, the periphery of the image The area becomes darker than the central area. On the other hand, when the first microlens 18 is provided in the peripheral region, the proportion of light emitted by the projection optical system 5 is smaller than when the second microlens 19 is provided in the peripheral region.

  Therefore, the first microlens layer 11 according to the present embodiment includes the first microlens 18 in the first region and the second microlens 19 in the second region. Although the effect of reducing speckle noise is smaller than that of the second micro lens 19, the first micro lens 18 has an effect of reducing speckle noise. Therefore, by using the first microlens layer 11, it is possible to realize a projector in which speckle noise of an image is reduced as a whole and illumination light utilization efficiency is high as a whole. In the central area of the image, speckle noise is greatly reduced compared to the peripheral area of the image, and high light utilization efficiency is obtained even in the peripheral area of the image.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the projector of the second embodiment is the same as that of the first embodiment, and the configuration of the microlens element is different from that of the first embodiment.
6 and 7, the same reference numerals are given to the same components as those used in the first embodiment, and the description thereof will be omitted.

  In the first embodiment, the microlens constituting the first microlens layer has a conical shape or a truncated cone shape. On the other hand, in the present embodiment, the microlens constituting the first microlens layer has a quadrangular pyramid shape or a quadrangular pyramid shape.

  As shown in FIGS. 6 and 7, the first microlens layer 23 has a plurality of microlenses arranged in an array. Each of the plurality of microlenses is arranged corresponding to the pixel position of the liquid crystal light valve 12. The plurality of microlenses includes a plurality of first microlenses 24 provided in a first area of the light modulation area, a plurality of second microlenses 25 provided in a second area of the light modulation area, And a plurality of third microlenses 26 provided in the third region of the light modulation region. Each of the first microlens 24, the second microlens 25, and the third microlens 26 is a plano-convex lens.

  In the example of the present embodiment, as shown in FIG. 7, the first microlens 24 is arranged in the outermost first row and the outermost first column. The third microlenses 26 are arranged in the second row from the outside and the second column from the outside. The second microlenses 25 are arranged in the middle 2 rows and 2 columns.

  The first microlens 24 has a quadrangular frustum shape. Therefore, a central portion that is a part of the convex surface 24 a of the first microlens 24 is a flat surface 24 c that is substantially parallel to the flat surface 24 b of the first microlens 24. The third microlens 26 has a quadrangular frustum shape. Therefore, a central portion that is a part of the convex surface 26 a of the third microlens 26 is a flat surface 26 c that is substantially parallel to the flat surface 26 b of the third microlens 26. The second microlens 25 has a quadrangular pyramid shape. The convex surface 25 a of the second microlens 25 is an inclined surface that is inclined with respect to the flat surface 25 b of the second microlens 25.

  In the following description, the surface with the smaller area is referred to as the upper surface among the two parallel surfaces of the quadrangular pyramid that forms the first microlens 24 and the third microlens 26, and the one with the larger area. The surface is referred to as the lower surface, and the surface inclined with respect to the upper surface and the lower surface is referred to as the inclined surface. In addition, the bottom surface of the quadrangular pyramid that forms the shape of the second microlens 25 is referred to as a lower surface, and a surface inclined with respect to the lower surface is referred to as an inclined surface.

  In all of the first microlens 24, the second microlens 25, and the third microlens 26, the inclination angle of the inclined surface with respect to the lower surface is the same. Further, when comparing the first microlens 24 and the third microlens 26 having a truncated pyramid shape, the area of the flat surface 24 c of the first microlens 24 is the same as that of the flat surface 26 c of the third microlens 26. Greater than area. In other words, the first microlens 24 and the third microlens 26 have the shape of a truncated pyramid when the quadrangular pyramid, which is the shape of the second microlens 25, is cut by a plane parallel to the plane 25b. doing. Further, if the shape of the second microlens 25 is regarded as a quadrangular frustum having an upper surface (flat surface) area of 0 (zero), the first microlens 24, the second microlens 25, and the third microlens. It can also be said that the area of the upper surface of the lens 26 increases from the center to the periphery of the first microlens layer 23 in the order of the second region, the third region, and the first region.

  When this configuration is realized, the first microlens 24, the second microlens 25, and the third microlens 26 have the same bottom surface dimensions, and the height from the bottom surface to the top surface or the apex is set to the second microlens. You may make it low toward the periphery from the center of the 1st micro lens layer 23 in order of this area | region, 3rd area | region, and 1st area | region. Alternatively, the height from the lower surface to the upper surface or the vertex is made the same, and the dimensions of the lower surface are directed from the center of the first microlens layer 23 to the periphery in the order of the second region, the third region, and the first region. You can make it bigger.

  Hereinafter, the operation of the first microlens layer 23 of the present embodiment will be described. The shape of each microlens is different from the shape of each microlens of the first microlens layer 11 described in the first embodiment, but the basic characteristics are the same. That is, the first microlens 24 has a function of emitting a part of the incident light L0 without diffusing. The second microlens 25 has a function of diffusing more light than the first microlens 24.

  The inventors performed a simulation in the same manner as in the first embodiment. The difference from the simulation performed in the first embodiment is the shape of the microlens and the dimensions of each part. The results will be described below.

  In this simulation, the height from the lower surface to the upper surface of each microlens is the same at 10 μm, and the inclination angle of the inclined surface is the same. For the second microlens 25, the length of one side of the upper surface was 0 (a quadrangular pyramid having no upper surface), and the length of one side of the lower surface was 16.4 μm. For the third microlens 26, the length of one side of the upper surface was 4 μm, and the length of one side of the lower surface was 20.4 μm. For the first microlens 24, the length of one side of the upper surface was 6 μm, and the length of one side of the lower surface was 22.4 μm.

  [Table 2] shows the dimensions of the above parts, the uniformity of the angular distribution, and the center strength.

  As shown in Table 2, in the case of the second microlens 25 having no upper surface (flat surface), the uniformity of the angular distribution is relatively high and the central strength is relatively low. On the other hand, in the case of the first microlens 24 having the upper surface (flat surface), the uniformity of the angular distribution is relatively low and the central strength is relatively high. Therefore, the second microlens 25 has higher uniformity of angular distribution than the first microlens 24, and the effect of reducing speckle noise is high. In addition, the first microlens 24 has higher light utilization efficiency than the second microlens 25. The third microlens 26 has intermediate characteristics between the second microlens 25 and the first microlens 24.

  Therefore, by using the first microlens layer 23 including the first microlens 24 in the first region and the second microlens 25 in the second region, the speckle noise of the image is reduced as a whole. In addition, it is possible to realize a projector that has high overall use efficiency of illumination light.

  In the second embodiment, an example using a quadrangular pyramid or quadrangular pyramid-shaped microlens has been described. However, other pyramid-shaped or truncated pyramid-shaped microlenses such as a triangular pyramid and a pentagonal pyramid can be used. .

  In the first and second embodiments, the conical or quadrangular pyramid-shaped microlens having no flat upper surface is disposed in the central region of the microlens element, but instead of this configuration, the microlens element is also disposed in the central region of the microlens element. Similarly to the peripheral region, a microlens having a truncated cone shape or a truncated pyramid shape having a flat upper surface may be arranged. In that case, the area of the upper surface of the microlens arranged in the central region may be smaller than the area of the upper surface of the microlens arranged in the peripheral region.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to FIGS.
The basic configuration of the projector of the third embodiment is the same as that of the first embodiment, and the configuration of the microlens element is different from that of the first embodiment.
8 to 10, the same reference numerals are given to the same components as those used in the first embodiment, and the description thereof will be omitted.

  In the first embodiment and the second embodiment, the shape of the plurality of microlenses constituting the first microlens layer is different between the microlens provided in the peripheral region and the microlens provided in the central region. . On the other hand, in the present embodiment, the shapes of the plurality of microlenses constituting the first microlens layer are all the same. Further, the refractive index is different between the microlens provided in the peripheral region and the microlens provided in the central region.

  As shown in FIGS. 8 and 9, the first microlens layer 29 has a plurality of microlenses arranged in an array. Each of the plurality of microlenses is arranged corresponding to the pixel position of the liquid crystal light valve 12. The plurality of microlenses includes a plurality of first microlenses 30 provided in a first region of the light modulation region, a plurality of second microlenses 31 provided in a second region of the light modulation region, A plurality of third microlenses 32 provided in the third region of the light modulation region. The first microlens 30, the second microlens 31, and the third microlens 32 all have a conical shape.

  In the example of this embodiment, as shown in FIG. 9, the first microlenses 30 are arranged in the outermost row and the outermost column. The third microlenses 32 are arranged in the second row from the outside and the second column from the outside. The second microlenses 31 are arranged in the middle 2 rows and 2 columns.

  The refractive indexes of the first microlens 30, the second microlens 31, and the third microlens 32 are sequentially decreased from the central region toward the peripheral region. That is, assuming that the refractive index of the first microlens 30 is n1, the refractive index of the second microlens 31 is n2, and the refractive index of the third microlens 32 is n3, the relationship of n1 <n3 <n2 is satisfied. Yes.

  The refractive index of a general transparent material constituting the microlens is, for example, about 1.5 to 1.6. For example, if the microlens is made of a resin having a refractive index of 1.5 and air is present on the light incident side of the microlens, the light is made up of air having a refractive index of 1.0 and a resin having a refractive index of 1.5. The light passes through the interface and enters the microlens. Therefore, when the refractive index of the microlens is large, the difference in refractive index from the substance existing on the light incident side becomes large, and the light incident on the microlens is refracted at a large angle. On the contrary, when the refractive index of the microlens is small, the difference in refractive index from the substance existing on the light incident side is small, and the light incident on the microlens is refracted at a small angle. This tendency is not limited to the case where air is present on the light incident side of the microlens, and the same is true when a substance having a refractive index smaller than that of the microlens is present.

  Therefore, a microlens with a high refractive index has a large degree of light diffusion, and the spread of the angular distribution of light emitted from the microlens is large. In the case of the present embodiment, the second microlens 31 in the central region has a relatively high refractive index, and thus has a great effect of reducing speckle noise. On the other hand, a microlens having a low refractive index has a small degree of light diffusion, and the spread of the angular distribution of light emitted from the microlens is small. In the present embodiment, since the first microlens 30 in the peripheral region has a relatively small refractive index, the light emission angle is relatively small. For this reason, less light is applied to the subsequent optical element, and the light utilization efficiency is higher than when the second microlens 31 is provided in the peripheral region. By using the first microlens layer 29 of the present embodiment, it is possible to realize a projector in which speckle noise of an image is reduced as a whole and illumination light usage efficiency is high as a whole.

  The inventors performed a simulation in the same manner as in the first embodiment. The difference from the simulation performed in the first embodiment is the shape and refractive index of the microlens. The results will be described below.

  FIG. 10A, FIG. 10B, and FIG. 10C are diagrams showing the angular distribution of the intensity of light emitted from one microlens.

  FIG. 10A is an angle distribution diagram of the first microlens 30. FIG. 10B is an angle distribution diagram of the third microlens 32. FIG. 10C is an angle distribution diagram of the second microlens 31. In the simulation, it is assumed that the shape of each microlens is a conical shape and a substance having a refractive index of 1.46 exists on the light incident side of the microlens. The substance having a refractive index of 1.46 is assumed to be an optical adhesive for fixing the microlens to another member, for example. The refractive index of the first microlens 30 was set to 1.5. The refractive index of the third microlens 32 was 1.55. The refractive index of the second microlens 31 was 1.62.

  Table 3 shows the refractive index and the uniformity of the angular distribution and the center intensity. The uniformity of the angular distribution is shown as a relative value when the uniformity of the angular distribution of the first microlens 30 is 1.

  As shown in FIG. 10, the shape of each microlens is the same, but the refractive index is different. Therefore, the spread of the angle distribution of the emitted light (the spread angle of the light beam) differs depending on the microlens. As can be seen from FIG. 10 and Table 3, in the case of the second microlens 31, the uniformity of the angular distribution is relatively high and the center intensity is relatively low. In the case of the first microlens 30, the uniformity of the angular distribution is relatively low and the central strength is relatively high. Thus, it was confirmed that the second microlens 31 having a high refractive index has higher uniformity of angular distribution and a high effect of reducing speckle noise than the first microlens 30 having a low refractive index. On the other hand, it was confirmed that the first microlens 30 having a low refractive index has a higher center intensity of emitted light than the second microlens 31 having a high refractive index, and has a high effect of improving the light utilization efficiency. It was confirmed that the third microlens 32 has an intermediate characteristic between the second microlens 31 and the first microlens 30.

[Fourth Embodiment]
Hereinafter, a fourth embodiment of the present invention will be described with reference to FIG.
The shape of each microlens of the microlens element of the fourth embodiment is different from that of the third embodiment.
In FIG. 11, the same components as those used in the third embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the third embodiment, the shape of the microlens constituting the first microlens layer is conical. On the other hand, in 4th Embodiment, the micro lens which comprises a 1st micro lens layer is a quadrangular pyramid shape.

  As shown in FIG. 11, the first microlens layer 35 has a plurality of microlenses arranged in an array. Each of the plurality of microlenses is arranged corresponding to the pixel position of the liquid crystal light valve 12. The plurality of microlenses include a plurality of first microlenses 36 provided in a first area in the light modulation area of the liquid crystal light valve 12, and a plurality of second microlenses 37 provided in a second area. And a plurality of third microlenses 38 provided in the third region. The first microlens 36, the second microlens 37, and the third microlens 38 all have a quadrangular pyramid shape.

  In the example of this embodiment, as shown in FIG. 11, the first microlenses 36 are arranged in the outermost row and the outermost column. The third microlenses 38 are arranged in the second row from the outside and the second column from the outside. The second microlenses 37 are arranged in the middle 2 rows and 2 columns.

  The refractive indexes of the first microlens 36, the second microlens 37, and the third microlens 38 are gradually decreased from the central region toward the peripheral region. That is, assuming that the refractive index of the first microlens 36 is n1, the refractive index of the second microlens 37 is n2, and the refractive index of the third microlens 38 is n3, the relationship of n1 <n3 <n2 is satisfied. Yes.

  In the present embodiment as well, the use of the first microlens layer 35 reduces the speckle noise of the image as a whole and realizes a projector having a high utilization efficiency of illumination light as a whole. The same effect as the embodiment can be obtained.

  In the third embodiment and the fourth embodiment, the shape of the microlens is a conical shape or a quadrangular pyramid shape, but the shape of the microlens is not limited thereto. As a modification of the microlens, for example, as shown in FIG. 12, a central lens 42a may be a convex lens having a curved surface, and a peripheral lens 42b may be a microlens 42 having a truncated cone shape.

The inventors also performed a simulation for the microlens of the present modification as in the first embodiment. The results will be described below.
As various parameters of the micro lens 42, as shown in FIG. 13, the height t from the lower surface to the apex of the central portion 42a is 4.1 μm, the inclination angle θ of the inclined surface of the peripheral portion 42b is 52 °, The diameter w was 11.4 μm, and the distance z between the lower surface of the microlens 42 and the liquid crystal light valve 12 was 14 μm. Similar to the fourth embodiment, the refractive index of the microlens was changed depending on the location. The refractive index of the first microlens was 1.5. The refractive index of the third microlens was 1.55. The refractive index of the second microlens was 1.62.

  The refractive index and the uniformity of the angular distribution and the central intensity are shown in [Table 4]. The uniformity of the angular distribution is shown as a relative value when the uniformity of the angular distribution of the second microlens is 1.

  As shown in Table 4, the second microlens with a high refractive index has higher uniformity of angular distribution and a higher speckle noise reduction effect than the first microlens with a low refractive index. The first microlens having a low refractive index has a higher center intensity than the second microlens having a high refractive index, and has a high effect of improving light utilization efficiency. The third microlens has intermediate characteristics between the second microlens and the first microlens. Therefore, it was found that the same tendency as in the third embodiment and the fourth embodiment was exhibited according to the difference in refractive index regardless of the shape of the microlens.

[Fifth Embodiment]
Hereinafter, a fifth embodiment of the present invention will be described with reference to FIG.
The configuration of the light modulation device of the fifth embodiment is the same as that of the first embodiment, but the configuration of the microlens element is different from that of the first embodiment.
In FIG. 14, the same components as those used in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Although the detailed description of the liquid crystal light valve is omitted in the above embodiment, the liquid crystal light valve includes a light shielding layer that partitions a plurality of pixels arranged in a matrix, a so-called black matrix. In order to increase the light use efficiency in the liquid crystal light valve, it is necessary to prevent the light incident on the liquid crystal light valve from being scattered by the black matrix. Therefore, it is important to provide a microlens on the light incident side of the liquid crystal light valve for collecting incident parallel light at the opening of the black matrix. From this viewpoint, in the first to fourth embodiments, the first microlens layer is provided on the light incident side of the liquid crystal light valve.

  As shown in FIG. 14, the light modulation device 45 of this embodiment includes a liquid crystal light valve 12, a first microlens layer 46, and a second microlens layer 47. The first microlens layer 46 and the second microlens layer 47 constitute a microlens element. The liquid crystal light valve 12 includes a light modulation region including a plurality of pixels. The first microlens layer 46 is provided on the light incident side of the liquid crystal light valve 12. The second microlens layer 47 is provided on the light emission side of the liquid crystal light valve 12. 14 to 16, for convenience, the liquid crystal light valve 12 is illustrated as having a plurality of pixels arranged in 3 rows and 3 columns. In this case, the area where one central pixel is arranged corresponds to the central area, and the area where the remaining pixels are arranged corresponds to the peripheral area.

  The first microlens layer 46 includes a plurality of microlenses 48 provided corresponding to all the pixels in the light modulation region of the liquid crystal light valve 12. One microlens 48 is provided for one pixel. The first microlens layer 46 of the present embodiment is different from the first microlens layers of the first to fourth embodiments, and the shape and refractive index of all the microlenses 48 constituting the first microlens layer 46. Are the same. The shape of the micro lens 48 is not particularly limited. For example, a convex lens having a general shape having a spherical surface may be used, or a plano-convex lens having a shape as used in the first to fourth embodiments may be used. Also good.

  The second microlens layer 47 is provided on the TFT array substrate 14. The second microlens layer 47 includes a region 47a corresponding to the peripheral region and a region 47b corresponding to the central region. A plurality of first convex lenses 49 are provided in the region 47a. The region 47b is provided with an air layer, and the refractive power of the region 47b can be regarded as zero. Therefore, the refractive power of the region 47a is larger than the refractive power of the region 47b. The plurality of first convex lenses 49 are provided corresponding to the plurality of pixels in the peripheral region of the light modulation region of the liquid crystal light valve 12. One first convex lens 49 is provided for one pixel in the peripheral region. The region 47b is disposed in the central region of the light modulation region of the liquid crystal light valve 12. That is, the refractive power of the second microlens layer 47 in the peripheral region is larger than the refractive power of the second microlens layer 47 in the central region. The shape of the first convex lens 49 is not particularly limited, and for example, a general convex lens having a spherical surface can be used. In this embodiment, the air layer is provided in the region 47b. However, a light transmissive member having no refractive power may be provided in the region 47b instead of the air layer. Further, the region from which the first convex lens 49 is provided to the region from the outermost periphery can be appropriately determined without any particular limitation. That is, the boundary between the peripheral region and the central region can be determined as appropriate.

  In the case of the light modulation device 45 of this embodiment, the light L0 incident on each microlens 48 of the first microlens layer 46 on the light incident side is focused to such an extent that it can pass through an opening of a black matrix (not shown). The liquid crystal light valve 12 emits light with a predetermined angular distribution. Light emitted from the peripheral region of the liquid crystal light valve 12 is converted into light L1 having a narrower angular distribution, that is, light L1 closer to parallel light, by passing through the first convex lens 49 of the second microlens layer 47. , And emitted from the microlens element (second microlens layer 47). On the other hand, the light L2 emitted from the central region of the liquid crystal light valve 12 with a predetermined angular distribution passes through the region 47b and is emitted from the microlens element while maintaining a relatively wide angular distribution. .

  In the light modulation device 45 of the present embodiment, the light L2 emitted from the central region of the light modulation region has a wider angular distribution and a higher angular distribution uniformity than the light L1 emitted from the peripheral region of the light modulation region. have. Therefore, a higher speckle noise reduction effect is obtained in the central region than in the peripheral region. On the other hand, the light L1 emitted from the peripheral region of the light modulation region has a narrower angular distribution than the light L2 emitted from the central region of the light modulation region. Therefore, in the peripheral region, less light is directed to the projection optical system at the subsequent stage, and a relatively high light utilization efficiency can be obtained. By using the light modulation device 45, it is possible to realize a projector in which the speckle noise of the image is reduced as a whole and the illumination light utilization efficiency is high as a whole.

  The light modulation device 45 of this embodiment does not include the first convex lens 49 in the central region on the light emission side of the liquid crystal light valve 12. On the other hand, as shown in FIG. 15, in the light modulation device 52 of the modified example, the second microlens layer 53 is added to the first convex lens 49 provided in the region 53 a having a relatively large refractive power. The second convex lens 54 may be provided in the region 53b having a relatively small refractive power. However, the refractive power of the second convex lens 54 is smaller than the refractive power of the first convex lens 49. In this case, the light L3 emitted from the central region of the liquid crystal light valve 12 is transmitted through the second convex lens 54 of the second microlens layer 53 in the same manner as the light L1 emitted from the peripheral region. Narrower light, that is, light that is closer to parallel light is converted and emitted.

  However, when the angular distribution of the emitted light is compared between the central region and the peripheral region, the second convex lens 54 has a refractive power smaller than that of the first convex lens 49. Therefore, the angular distribution of the emitted light L3 in the central region is It is wider than the angular distribution of the emitted light L1 in the region. As a result, a higher speckle noise reduction effect is obtained in the central region than in the peripheral region. On the other hand, the light L1 emitted from the peripheral region of the light modulation region has a narrower angular distribution than the light L3 emitted from the central region of the light modulation region. Therefore, in the peripheral region, less light is directed to the projection optical system in the subsequent stage than in the central region, and a relatively high light utilization efficiency can be obtained.

[Sixth Embodiment]
Hereinafter, a sixth embodiment of the present invention will be described with reference to FIG.
The basic configuration of the light modulation device of the sixth embodiment is the same as that of the fifth embodiment, and the configuration of the second microlens layer on the light emission side is different from that of the fifth embodiment.
In FIG. 16, the same components as those in FIG. 14 used in the fifth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 16, the light modulation device 57 of this embodiment includes a liquid crystal light valve 12, a first microlens layer 46, and a second microlens layer 58. The first microlens layer 46 and the second microlens layer 58 constitute a microlens element. The liquid crystal light valve 12 includes a light modulation region including a plurality of pixels. The first microlens layer 46 is provided on the light incident side of the liquid crystal light valve 12. The second microlens layer 58 is provided on the light emission side of the liquid crystal light valve 12. The configuration of the first microlens layer 46 is the same as that of the fifth embodiment.

  The second microlens layer 58 includes a region 58a corresponding to the peripheral region and a region 58b corresponding to the central region. The region 58a is provided with an air layer, and the refractive power of the region 58a can be regarded as zero. A concave lens 59 having a negative refractive power is provided in the region 58b. Therefore, it can be said that the refractive power of the region 58a is larger than the refractive power of the region 58b. The plurality of concave lenses 59 are provided corresponding to the pixels in the central region of the light modulation region of the liquid crystal light valve 12. One concave lens 59 is provided for one pixel in the central region. The region 58a is disposed in the peripheral region of the light modulation region of the liquid crystal light valve 12. That is, the refractive power of the second microlens layer 58 in the peripheral region is larger than the refractive power of the second microlens layer 58 in the central region. The shape of the concave lens is not particularly limited, and for example, a general concave lens having a spherical surface can be used. In the present embodiment, an air layer is provided in the region 58a. However, a light transmissive member having no refractive power may be provided in the region 58a instead of the air layer. Further, the formation range of the concave lens is not particularly limited and can be determined as appropriate. That is, the boundary between the peripheral region and the central region can be determined as appropriate.

  In the case of the light modulation device 57 of the present embodiment, the light incident on the microlens 48 of the first microlens layer 46 on the light incident side is focused to such an extent that it can be transmitted through an opening of a black matrix (not shown). Light is emitted from the light valve 12 with a predetermined angular distribution. The light emitted from the peripheral area of the liquid crystal light valve 12 passes through the area 58a and is emitted from the microlens element while maintaining the angular distribution determined by the microlens 48. On the other hand, the light emitted from the central region of the liquid crystal light valve 12 is converted to the light L4 having a wider angular distribution by passing through the concave lens 59 of the second microlens layer 58, and emitted from the microlens element. .

  In the light modulation device 57 of the present embodiment, the light L4 emitted from the central region of the light modulation region has a wider angular distribution and a higher angular distribution uniformity than the light L2 emitted from the peripheral region of the light modulation region. have. Therefore, a higher speckle noise reduction effect is obtained in the central region than in the peripheral region. On the other hand, the light L2 emitted from the peripheral region of the light modulation region has a narrower angular distribution than the light L4 emitted from the central region of the light modulation region. Therefore, in the peripheral region, less light is directed to the projection optical system at the subsequent stage, and a relatively high light utilization efficiency can be obtained. By using the light modulation device 57, it is possible to realize a projector in which the speckle noise of the image is reduced as a whole and the illumination light utilization efficiency is high as a whole.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first to fourth embodiments, the outline of each of the first area, the second area, and the third area is rectangular with respect to the rectangular light modulation area. I can't. As shown in FIG. 17, for the rectangular light modulation region M, the first region contour R1, the second region contour R2, and the third region contour R3 may be circular, for example.

  Further, as shown in FIG. 18, the rectangular light modulation region M may be divided in the longitudinal direction, and the two first regions H1 may be arranged so as to sandwich the second region H2. Further, it is not always necessary to set the third area. That is, the third microlens is not essential.

  In the above-described embodiment, the microlens element having a configuration in which either the shape or the refractive index of the microlens is different between the peripheral region and the central region of the light modulation region is illustrated, but instead of this configuration, the light modulation region A microlens element having a configuration in which both the shape and the refractive index of the microlens are different between the peripheral region and the central region may be employed. For example, the area of the upper surface of the microlens in the peripheral region of the light modulation region may be increased and the refractive index may be decreased, the area of the upper surface of the microlens in the central region may be decreased, and the refractive index may be increased.

  In the first and second embodiments, the inclination angle of the inclined surface with respect to the lower surface is the same in the first microlens and the second microlens, but the present invention is not limited to this. The tilt angle of the first microlens may be smaller than the tilt angle of the second microlens.

  In the modification of the fifth embodiment shown in FIG. 15, the first convex lens 49 and the second convex lens 54 are provided, but the present invention is not limited to this. Instead of the second convex lens 54, a concave lens 59 shown in FIG. 16 may be provided.

  In addition, the shape, number, arrangement, material, and the like of the various components of the first microlens layer, the second microlens layer, the light modulation device, and the projector are not limited to those exemplified in the above embodiment, and may be appropriately selected. It can be changed.

  DESCRIPTION OF SYMBOLS 1 ... Projector, 2R, 2G, 2B ... Light source device, 3R, 3G, 3B, 45, 52, 57 ... Light modulation device, 5 ... Projection optical system, 11, 23, 29, 35 ... 1st micro lens layer, DESCRIPTION OF SYMBOLS 12 ... Liquid crystal light valve (light modulation element) 18, 24, 30, 36 ... 1st micro lens, 19, 25, 31, 37 ... 2nd micro lens, 42 ... Micro lens, 47, 53, 58 ... 2nd micro lens layer, 49 ... 1st convex lens, 54, 59 ... 2nd convex lens

Claims (11)

A microlens element provided in a light modulation element having a light modulation region including a plurality of pixels,
Comprising a first microlens layer;
The first microlens layer includes a first microlens provided in a peripheral region of the first microlens layer, and a second microlens provided in a central region of the first microlens layer. Including,
Each of the first microlens and the second microlens is composed of a plano-convex lens,
A part of the convex surface of the first microlens is a flat surface,
A part of the convex surface of the second microlens is a flat surface,
An area of the flat surface of the first microlens is larger than an area of the flat surface of the second microlens;
The uniformity of the angular distribution of the light incident on the second microlens and emitted from the first microlens layer is incident on the first microlens and emitted from the first microlens layer. Higher than the uniformity of the angular distribution of light,
The central intensity of the light incident on the first microlens and emitted from the first microlens layer is the intensity of the light incident on the second microlens and emitted from the first microlens layer. A microlens element having a higher central strength. A microlens element provided in a light modulation element having a light modulation region including a plurality of pixels,
Comprising a first microlens layer;
The first microlens layer includes a first microlens provided in a peripheral region of the first microlens layer, and a second microlens provided in a central region of the first microlens layer. Including,
Each of the first microlens and the second microlens is composed of a plano-convex lens,
A part of the convex surface of the first microlens is a flat surface,
The convex surface of the second microlens is composed of an inclined surface having a conical shape, does not have a flat surface,
The uniformity of the angular distribution of the light incident on the second microlens and emitted from the first microlens layer is incident on the first microlens and emitted from the first microlens layer. Higher than the uniformity of the angular distribution of light,
The central intensity of the light incident on the first microlens and emitted from the first microlens layer is the intensity of the light incident on the second microlens and emitted from the first microlens layer. A microlens element having a higher central strength.   The microlens element according to claim 1 or 2, wherein a refractive index of the first microlens is smaller than a refractive index of the second microlens. A second microlens layer;
2. The microlens element according to claim 1, wherein a refractive power of the second microlens layer in the peripheral region is larger than a refractive power of the second microlens layer in the central region. The microlens element according to claim 4, wherein the second microlens layer includes a first convex lens provided in the peripheral region. The second microlens layer further includes a second convex lens provided in the central region,
6. The microlens element according to claim 5, wherein the refractive power of the second convex lens is smaller than the refractive power of the first convex lens.   The microlens element according to claim 4, wherein the second microlens layer includes a concave lens provided in the central region. A light modulation element including a light modulation region including a plurality of pixels;
A microlens element provided in the light modulation element,
8. The light modulation device according to claim 1, wherein the microlens element is the microlens element according to any one of claims 1 to 7. The microlens element is the microlens element according to any one of claims 1 to 3,
The light modulation device according to claim 8, wherein the microlens element is provided on a light incident side of the light modulation element. The microlens element is the microlens element according to any one of claims 4 to 7,
The first microlens layer is provided on the light incident side of the light modulation element,
The light modulation device according to claim 8, wherein the second microlens layer is provided on a light emission side of the light modulation element. A light source device;
A light modulation device for modulating light from the light source device;
A projection optical system that projects the light modulated by the light modulation device,
The projector according to claim 8, wherein the light modulation device is the light modulation device according to claim 8.