JP5262850B2 - projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector of high light use efficiency with a simple and compact configuration. <P>SOLUTION: The projector includes: a plurality of light source parts for emitting coherent light which is the color lights of mutually different wavelength regions; a CGH 12 which is a diffraction optical element for diffracting the coherent light and emitting diffracted light; a parallelizing lens 13 for parallelizing the luminous fluxes of the diffracted light; a spatial light modulator 14 for modulating the light made incident from the parallelizing lens 13 according to image signals; and a prism 16 which is a deflection means provided for at least one of the plurality of color lights from the plurality of light source parts, for deflecting the light. The incidence angle and emission angle of a main light beam in the diffraction optical element are almost the same for all of the plurality of color lights, and the light is deflected by the deflection means, the plurality of color lights parallelized by the parallelizing lens 13 being superimposed in the irradiation region of the spatial light modulator 14. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a projector, and more particularly to a projector that displays an image using diffracted light by a diffractive optical element.

  A so-called single-plate projector that modulates a plurality of color lights with a single spatial light modulation device can have a simpler configuration and a smaller size than when a plurality of spatial light modulation devices provided for each color light is used. There is an advantage. Conventionally, as one of the single-plate projectors, one that adopts a color display system that distributes each color light to each pixel by causing each color light to enter the spatial light modulator at different incident angles has been proposed ( For example, see Patent Document 1). In a single-plate projector, a technique has been proposed in which each color light is distributed to each pixel using a diffractive optical element (see, for example, Patent Document 2). The diffractive optical element diffracts the laser beam, which is coherent light, to shape and enlarge the irradiation region and to uniformize the light amount distribution in the irradiation region. By providing the diffractive optical element with a plurality of functions, the projector can be made more compact. As the diffractive optical element, for example, a computer generated hologram (CGH) is used. The advantages of CGH are that it is relatively easy to design, can produce highly accurate shapes, and can easily produce duplicates by transfer.

Japanese Patent Laid-Open No. 4-60538 JP 2007-286110 A

  It is known that the efficiency of obtaining desired diffracted light decreases as the CGH deflects the light so that the angle of the principal ray of the emitted light becomes larger than the principal ray of the incident light. When superimposing a plurality of color lights from the CGH in the irradiation region of one spatial light modulator, a reduction in light utilization efficiency due to deflection of each color light by the CGH becomes a problem. It is an object of the present invention to provide a projector with high light utilization efficiency with a simple and small configuration.

  In order to solve the above-described problems and achieve the object, a projector according to the present invention emits diffracted light by diffracting coherent light with a plurality of light source units that emit coherent light that is colored light in different wavelength ranges. A diffractive optical element, a collimating lens that collimates a light beam of diffracted light, a spatial light modulator that modulates light incident from the collimating lens according to an image signal, and a plurality of color lights from a plurality of light source units Deflection means provided for at least one of them, and deflecting the light, and the incident light and the exit angle of the principal ray in the diffractive optical element are substantially the same for each of the plurality of color lights, and the deflection means A plurality of color lights collimated by a collimating lens are superposed in the irradiation area of the spatial light modulator by deflecting the light.

  Decreasing diffraction efficiency by deflecting at least one of a plurality of color lights using a deflecting means and eliminating the change in chief ray angle in the diffractive optical element for each color light. Reduce. By reducing the decrease in diffraction efficiency of each color light, the decrease in light utilization efficiency for each color light is reduced. The projector can have a simple and compact configuration by using a spatial light modulation device that modulates a plurality of color lights and a diffractive optical element. Thereby, a projector with high light utilization efficiency can be obtained with a simple and small configuration.

  As a preferred aspect of the present invention, it is desirable that the deflecting unit is provided in an optical path between the diffractive optical element and the collimating lens, and deflects the diffracted light incident from the diffractive optical element. Thereby, at least one of the plurality of color lights can be deflected, and the respective color lights can be superimposed in the irradiation region.

  As a preferred embodiment of the present invention, it is desirable that at least one of the plurality of color lights is incident on the collimating lens from the diffractive optical element without passing through the deflecting unit. As a result, the number of parts can be reduced as compared with the case where deflection means is provided for all color lights.

  As a preferred aspect of the present invention, it is desirable that the deflecting unit is provided in an optical path between the plurality of light source units and the diffractive optical element, and deflects the coherent light incident from the plurality of light source units. Thereby, at least one of the plurality of color lights can be deflected, and the respective color lights can be superimposed in the irradiation region.

  Moreover, as a preferable aspect of the present invention, it is desirable that the deflecting unit includes a prism. Thereby, a light beam can be deflected by refraction at the prism.

  Moreover, as a preferable aspect of the present invention, it is desirable that the deflecting unit includes a lens. Thereby, the light beam can be deflected by refraction at the lens.

  Moreover, as a preferable aspect of the present invention, it is desirable that the spatial light modulator is arranged by shifting the center position of the irradiation region from the optical axis of the collimating lens. Accordingly, it is possible to realize a configuration in which each color light incident at different incident angles is distributed to the sub-pixels by using a microlens array in which the center position of the microlens and the center position of the pixel are substantially matched.

  Moreover, as a preferable aspect of the present invention, the microlens array includes a plurality of microlenses provided at substantially the same pitch as the pixels in the irradiation region, and the microlens array has a two-dimensional direction in which the plurality of microlenses are arranged in parallel. In this case, it is desirable that the center position of the microlens is shifted from the center position of the pixel. Since each light beam of each color can pass near the center of the collimating lens, the collimating lens can be reduced in size, and aberrations caused by the collimating lens can be reduced.

  Moreover, as a preferable aspect of the present invention, the microlens array includes a plurality of microlenses provided at substantially the same pitch as the pixels in the irradiation region, and the microlens array has a two-dimensional direction in which the plurality of microlenses are arranged in parallel. In this case, it is desirable that the center position of the microlens is substantially aligned with the center position of the pixel. Thus, by arranging the spatial light modulator by shifting the center position from the optical axis, it is possible to realize a configuration in which each color light incident at different incident angles is distributed to the sub-pixels.

  Furthermore, a projector according to the present invention includes a plurality of light source units that emit coherent light that is colored light in different wavelength ranges, a diffractive optical element that diffracts coherent light incident from the plurality of light source units, and emits diffracted light. A collimating lens that collimates the light beam of the diffracted light incident from the diffractive optical element, and a spatial light modulator that modulates the light incident from the collimating lens in accordance with an image signal, However, the incident angle and the exit angle of the chief ray in the diffractive optical element are substantially the same, and the plurality of light source units emit coherent light so that the chief rays intersect at a position on the optical axis of the collimating lens. Thus, the plurality of color lights collimated by the collimating lens are superimposed on the irradiation region of the spatial light modulator.

  The light source section is arranged so that the chief rays intersect at a position on the optical axis of the collimating lens, and the change in the light utilization efficiency for each color light is reduced by eliminating the change in the angle of the chief ray in the diffractive optical element for each color light. . By appropriately setting the direction of the light source unit, the projector can superimpose each color light in the irradiation region without using an element for deflection. Thereby, a projector with high light utilization efficiency can be obtained with a simple and small configuration.

1 is a schematic diagram illustrating a schematic configuration of a projector according to Embodiment 1. FIG. It is a perspective view which shows a part of structure shown in FIG. It is a plane schematic diagram of the pixel in a spatial light modulation device. It is a figure explaining the general structure of the conventional single plate type projector. It is a figure which shows the relationship between diffraction efficiency and the difference of the incident angle of a chief ray, and an output angle. FIG. 3 is a diagram illustrating a characteristic part of the projector according to the first embodiment. It is a cross-sectional schematic diagram explaining a response | compatibility with a pixel and a micro lens. FIG. 6 is a diagram illustrating a characteristic part of a projector according to a second embodiment. It is a cross-sectional schematic diagram explaining a response | compatibility with a pixel and a micro lens. FIG. 10 is a diagram illustrating a characteristic part of a projector according to a third embodiment. FIG. 10 is a diagram illustrating a characteristic part of a projector according to a fourth embodiment.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a schematic diagram illustrating a schematic configuration of a projector 10 according to a first embodiment of the invention. The projector 10 is a so-called single-plate projector that modulates three color lights by one spatial light modulator 14. The light source unit for R light 11R, the light source unit for G light 11G, and the light source unit for B light 11B are light source units that emit laser light that is coherent light, and emit color light in different wavelength ranges. The R light source unit 11R is a laser light source that emits R light, and includes, for example, a semiconductor laser. The G light source unit 11G is a laser light source that emits G light, and includes, for example, a semiconductor pumped solid state (DPSS) laser. The B light source unit 11B is a laser light source that emits B light, and includes, for example, a semiconductor laser.

  The CGH 12, which is a diffractive optical element, diffracts the laser light incident from the color light source units 11R, 11G, and 11B and emits diffracted light. The CGH 12 shapes the laser beam having a Gaussian intensity distribution into the rectangular shape of the spatial light modulator 14 and further uniformizes the light amount distribution. For example, the projector 10 displays an image by modulating the first-order diffracted light generated by the CGH 12.

  The prisms 16 serving as deflecting means are provided at positions where the R light emitted from the CGH 12 is incident and positions where the G light is incident. The prism 16 deflects the diffracted light from the CGH 12 by refraction at the interface. The collimating lens 13 collimates the B light beam incident from the CGH 12, the R light beam incident from the CGH 12 via the prism 16, and the G light beam incident from the CGH 12 via the prism 16. The CGH 12, the prism 16, and the collimating lens 13 superimpose each color light in the irradiation area of the spatial light modulator 14.

  The spatial light modulator 14 modulates the light incident from the collimating lens 13 according to the image signal. The spatial light modulator 14 is, for example, a transmissive liquid crystal display device. The spatial light modulator 14 has a microlens array (not shown) in which a plurality of microlenses are arranged in parallel. The projection lens 15 projects the light modulated by the spatial light modulator 14 onto a screen (not shown). The microlens array is not limited to the one attached to the spatial light modulator 14, and may be provided separately from the spatial light modulator 14.

  FIG. 2 is a perspective view showing a part of the configuration shown in FIG. The projector 10 includes one R light source unit 11R, one B light source unit 11B, and two G light source units 11G. The color light source units 11R, 11G, and 11B are installed so that the chief rays of the emitted light beams are substantially parallel to each other. The color light source units 11R, 11G, and 11B are arranged in a matrix of two rows and two columns in the plane direction perpendicular to the principal ray of the emitted light beam. Note that the principal ray is a ray at the center of the light beam, and is represented by an alternate long and short dash line in each figure.

  The CGH 12 is one of surface relief type diffractive optical elements having minute irregularities on the surface. Each color light from each color light source unit 11R, 11G, 11B is incident on a different area of the incident surface of CGH12. In the CHG 12, the surface conditions including the width of the unevenness and the arrangement pattern are optimized according to the wavelength of the color light for each region where the color light is incident. As a design method for optimizing the surface condition, a predetermined calculation method (simulation method) such as an iterative Fourier transform is used.

  For example, the CGH 12 is manufactured by using a so-called nanoimprint technique in which a mold having a desired shape is formed and then the shape of the mold is thermally transferred to the substrate. In addition, the CHG 12 may be manufactured by another conventionally used method as long as a desired shape can be formed. The CGH 12 may be divided for each color light. The diffractive optical element is not limited to the CGH 12, and other surface relief type diffractive optical elements, volume type diffractive optical elements manufactured by a two-beam interference method, or the like may be used.

  FIG. 3 is a schematic plan view of the pixel 17 in the spatial light modulator 14. In the figure, four of the large number of pixels 17 in the spatial light modulator 14 are shown. The pixel 17 includes one R light sub-pixel 18R, one B light sub-pixel 18B, and two G light sub-pixels 18G. The R light sub-pixel 18R modulates the R light according to the image signal. The G light sub-pixel 18G modulates the G light according to the image signal. The B light sub-pixel 18B modulates the B light according to the image signal. The four sub-pixels 18R, 18G, and 18B constituting one pixel 17 are arranged in a matrix of two rows and two columns on the irradiated surface. The arrangement of the color light source units 11R, 11G, and 11B corresponds to the arrangement of the sub-pixels 18R, 18G, and 18B. Note that the pixel arrangement described in this embodiment is an example, and any conventionally known arrangement may be used. The projector 10 can be appropriately configured according to the pixel arrangement of the spatial light modulator 14.

  FIG. 4 illustrates a general configuration employed by a conventional single-plate projector provided with the CGH 21. In FIG. 4, R light from the R light source unit 11R and B light from the B light source unit 11B are illustrated, and illustration of the G light from the G light source unit 11G is omitted. And In general, each element constituting the optical system of the projector is arranged around the optical axis AX. The optical axis AX is the optical axis of the collimating lens 13. Each color light source unit 11R, 11G, and 11B is disposed around the optical axis AX. The center position C of the irradiation area of the spatial light modulator 14 is a position on the optical axis AX.

  The light beams of the respective colors are incident on the CGH 21 incident surface at substantially symmetrical positions with the optical axis AX as the center. The CGH 21 deflects the light beams of the respective color lights in order to superimpose the respective color lights in the irradiation region centered on the optical axis AX. Both the principal ray LR of the R light and the principal ray LB of the B light are bent toward the optical axis AX side by diffraction at the CGH 21. The principal ray of G light is also bent in the same manner as the principal ray LR of R light and the principal ray LB of B light. The difference between the incident angle and the outgoing angle of the chief ray in the CGH 21 occurs equally in each color light.

  FIG. 5 is a graph showing the relationship between the diffraction efficiency of the R light and B light by the CGH 21 and the difference between the incident angle and the outgoing angle of the principal ray in the CGH 21. The diffraction efficiency is assumed to be the ratio of the first-order diffracted light to the entire light emitted from the CGH 21. For both B light and R light, the diffraction efficiency decreases as the difference between the incident angle and the outgoing angle of the principal ray increases. The decrease in diffraction efficiency becomes more remarkable as the wavelength of light is shorter. As described above, if each color light is deflected by the CGH 21, the use efficiency of each color light is lowered.

  FIG. 6 illustrates characteristic portions of the projector 10 according to the present embodiment. Also in FIG. 6, illustration of the G light from the G light source unit 11G is omitted. Each color light source unit 11R, 11G, and 11B is disposed around the optical axis AX. Both the principal ray of each color light incident on the CGH 12 and the principal ray of each color light emitted from the CGH 12 are substantially perpendicular to the incident surface of the CGH 12 and substantially parallel to the optical axis AX. In each color light, the incident angle and the emission angle of the principal ray in the CGH 12 are substantially the same. The incident angle and the outgoing angle of the principal ray are both angles formed by the optical axis AX and the principal ray. In the present embodiment, the incident angle and the emission angle of the principal ray of each color light are both zero.

  The light beam of B light enters the collimating lens 13 from the CGH 12 without passing through the deflecting means. The principal ray LB of the B light is substantially parallel to the optical axis AX when entering the collimating lens 13 and the same as when entering the CGH 12. The spatial light modulator 14 is arranged by shifting the center position C from the optical axis AX to the principal ray LB of B light.

  On the other hand, the light beam of R light exits from the CGH 12, is deflected by passing through the prism 16, and enters the collimating lens 13. The principal ray LR of the R light is bent by the prism 16 and proceeds in a direction gradually approaching the principal ray LB of the B light. The chief ray of the G light also travels in a direction that gradually approaches the chief ray LB of the B light through the prism 16 from the CGH 12. The chief rays of each color light coincide at the center position C. The projector 10 superimposes each color light in the irradiation region of the spatial light modulator 14 through diffraction by the CGH 12, deflection by the prism 16, and parallelization by the collimating lens 13.

  FIG. 7 is a schematic cross-sectional view for explaining the correspondence between the pixel 17 and the microlens 19. The plurality of microlenses 19 constituting the microlens array are provided at the same pitch as the pixels 17 in the irradiation region of the spatial light modulator 14. The plurality of microlenses 19 are arranged in an array in a two-dimensional direction perpendicular to the optical axis AX. Further, as indicated by a two-dot chain line in the figure, the center position of the microlens 19 and the center position of the pixel 17 coincide with each other in a plane perpendicular to the optical axis AX. Since each color light is incident on the microlens 19 at a different incident angle for each color light, it is condensed on the sub-pixels 18R, 18G, and 18B at different positions for each color light. The projector 10 can realize a configuration in which each color light incident at different incident angles is distributed to the sub-pixels 18R, 18G, and 18B by arranging the spatial light modulator 14 by shifting the center position C from the optical axis AX. Also, by providing the microlens array, each color light incident on the microlens 19 can be condensed at different positions, and each color light can be distributed to each subpixel with high accuracy.

  The projector 10 can have a simple and small configuration by using the spatial light modulation device 14 that modulates each color light and the CGH 12. Also, the prism 16 is used to deflect the R light and the G light, and by eliminating the chief ray angle change in the CGH 12 for each color light, the reduction in diffraction efficiency due to the angle change in the CGH 12 for each color light is reduced. By reducing the decrease in diffraction efficiency of each color light, the decrease in light utilization efficiency for each color light is reduced. Thereby, there exists an effect that it can be made high light utilization efficiency with a simple and small structure. Note that the prism 16 is not limited to the case where the prism 16 is provided at a position where the R light emitted from the CGH 12 is incident and a position where the G light is incident. The prism 16 may be provided for at least one of the R light, the G light, and the B light as long as each color light can be superimposed in the irradiation region of the spatial light modulator 14. It may be provided. Further, the prism 16 may be provided for all of R light, G light, and B light. The deflecting means is not limited to the prism 16, and any element that deflects light may be used. For example, a lens may be used as the deflection unit.

  FIG. 8 illustrates a characteristic part of the projector according to the second embodiment of the invention. This embodiment is characterized in that the spatial light modulator 14 is arranged so that the center position C is on the optical axis AX. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In FIG. 8, R light from the R light source unit 11R and B light from the B light source unit 11B are illustrated, and illustration of the G light from the G light source unit 11G is omitted. And The principal ray LB of the B light substantially coincides with the optical axis AX. The light source unit 11B for B light is disposed on the optical axis AX. The chief rays of each color light intersect at the center position C of the spatial light modulator 14.

  FIG. 9 is a schematic cross-sectional view for explaining the correspondence between the pixel 17 and the microlens 19. As indicated by a two-dot chain line in the figure, the center position of the microlens 19 and the center position of the B light sub-pixel 18B coincide with each other in a plane perpendicular to the optical axis AX. In the present embodiment, the microlens array is arranged by shifting the center position of the microlens 19 from the center position of the pixel 17 to the position of the B light sub-pixel 18B in the two-dimensional direction in which the plurality of microlenses 19 are arranged in parallel. Has been.

  By matching the center position of the microlens 19 with the center position of the B light sub-pixel 18B, the B light traveling substantially parallel to the optical axis AX is condensed by the B light sub-pixel 18B. Further, the R light and the G light are incident on the micro lens 19 at different incident angles, and are condensed on the sub-pixels 18R and 18G, respectively. Also in the case of the present embodiment, the projector can have a simple and small configuration and high light utilization efficiency.

  According to the present embodiment, since the light beams of the respective color lights can pass through the central portion of the collimating lens 13, the collimating lens 13 can be reduced in size. Further, the collimating lens 13 can use only a portion where the spherical aberration can be reduced. Thereby, even when an inexpensive spherical lens is applied as the collimating lens 13, the aberration caused by the collimating lens 13 can be reduced.

  The projector according to the present embodiment is not limited to the case where the B light source unit 11B is disposed on the optical axis AX, and any one of the R light source unit 11R and the G light source unit 11G is used as the optical axis. It is good also as arrange | positioning on AX. In the microlens array, the center position of the microlens 19 coincides with either the center position of the R light subpixel 18R or the center position of the G light subpixel 18G according to the light source unit arranged on the optical axis AX. Are arranged as follows.

  Note that the prism 16 is not limited to the case where the prism 16 is provided at a position where the R light emitted from the CGH 12 is incident and a position where the G light is incident. The prism 16 may be provided for at least one of the R light, the G light, and the B light as long as each color light can be superimposed in the irradiation region of the spatial light modulator 14. It may be provided. Further, the prism 16 may be provided for all of R light, G light, and B light. The deflecting means is not limited to the prism 16, and any element that deflects light may be used. For example, a lens may be used as the deflection unit.

  FIG. 10 illustrates a characteristic part of the projector according to the third embodiment of the invention. The present embodiment is characterized by having a deflecting means provided in the optical path between the light source units 11R, 11G, 11B and CGH 12 for each color light. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. 10 exemplifies the R light from the R light source unit 11R and the B light from the B light source unit 11B, and omits illustration of the G light from the G light source unit 11G. And Each color light source unit 11R, 11G, and 11B is disposed around the optical axis AX. All of the principal rays of the light beams emitted from the color light source units 11R, 11G, and 11B are substantially parallel to the optical axis AX. The center position C of the irradiation area of the spatial light modulator 14 is a position on the optical axis AX.

  The convex lens 21 which is a deflecting unit is in the optical path between the R light source unit 11R and the CGH 12, in the optical path between the B light source unit 11B and the CGH 12, and in the optical path between the G light source unit 11G and the CGH 12. Each is provided. The convex lens 21 deflects each color light incident from each color light source unit 11R, 11G, 11B. The convex lens 21 is arranged so that the chief rays of each color light are incident on a position away from the center of the convex lens 21. The principal ray LR of R light, the principal ray LB of B light, and the principal ray of G light are each bent toward the optical axis AX by the refraction of the convex lens 21.

  The chief rays of each color light inclined with respect to the optical axis AX are not converted in angle before and after entering the CGH 12, and proceed with the same inclination. In each color light, the incident angle and the emission angle of the principal ray in the CGH 12 are substantially the same. The chief rays of each color light intersect at a position on the optical axis AX in the collimating lens 13. The projector superimposes each color light in the irradiation region of the spatial light modulator 14 through deflection by the convex lens 21, diffraction by the CGH 12, and parallelization by the collimating lens 13. In the case of the present embodiment, the microlens array is arranged such that the center position of the microlens 19 (see FIG. 7) and the center position of the pixel 17 (see FIG. 3) coincide in a plane perpendicular to the optical axis AX. Has been placed. Also in the case of the present embodiment, the projector can have a simple and small configuration and high light utilization efficiency.

  According to the present embodiment, high light utilization efficiency can be easily obtained by adding a deflecting means to the configuration used in the conventional single-plate projector. The convex lens 21 used as the deflecting unit reduces the diffusion angle of the light beam emitted from the semiconductor laser provided in the R light source unit 11R and the B light source unit 11B. Increasing the etendue can be suppressed by reducing the beam diameter on the incident surface of the CGH 12, and the incident angle of the light beam incident on the spatial light modulator 14 can be reduced. Since the projector can reduce the incident angle of the light beam incident on the spatial light modulator 14, the projector can efficiently modulate the light incident on the spatial light modulator 14, and high light utilization efficiency can be obtained.

  The DPSS laser included in the G light source unit 11G emits a parallel light beam. The convex lens 21 diffuses the light beam emitted from the DPSS laser. By diffusing the parallel light flux, it is possible to make the zero-order light that is not used for beam shaping and exits from the CGH 12 as it is unnoticeable. As a result, it is possible to prevent the portion where the zero-order light and the diffracted light overlap from occurring in the image as a bright and conspicuous point. The deflecting unit is not limited to the convex lens 21, and any element that deflects light may be used. For example, a prism may be used as the deflecting unit.

  FIG. 11 illustrates a characteristic part of the projector according to the fourth embodiment of the invention. This embodiment is characterized in that each color light source unit 11R, 11G, and 11B emits laser light in different directions. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In FIG. 11, R light from the R light source unit 11R and B light from the B light source unit 11B are illustrated, and illustration of the G light from the G light source unit 11G is omitted. And

  Each color light source unit 11R, 11G, and 11B is disposed around the optical axis AX. In addition, the light source units 11R, 11G, and 11B for each color light are arranged such that the surface on which the laser light is emitted is slightly inclined toward the optical axis AX side. The principal ray of each color light emitted from each color light source unit 11R, 11G, 11B is tilted so as to gradually approach the optical axis AX. The center position C of the irradiation area of the spatial light modulator 14 is a position on the optical axis AX.

  The chief rays of each color light inclined with respect to the optical axis AX are not converted in angle before and after entering the CGH 12, and proceed with the same inclination. In each color light, the incident angle and the emission angle of the principal ray in the CGH 12 are substantially the same. The chief rays of each color light intersect at a position on the optical axis AX in the collimating lens 13. The projector superimposes in the irradiation area of the spatial light modulator 14 by diffracting each color light from each inclined light source unit 11R, 11G, 11B by the CGH 12 and making it parallel by the collimating lens 13. Let

  In the case of the present embodiment, the microlens array is arranged such that the center position of the microlens 19 (see FIG. 7) and the center position of the pixel 17 (see FIG. 3) coincide in a plane perpendicular to the optical axis AX. Has been placed. According to the present embodiment, by appropriately setting the direction of the light source unit, it is possible to superimpose each color light in the irradiation area without using an element for deflection. Also in the case of the present embodiment, the projector can have a simple and small configuration and high light utilization efficiency.

  The projector may be either a front projection type projector or a rear projector. A front projection type projector is a projector for viewing an image by projecting light on a screen and observing light reflected on the screen. The rear projector is a projector that appreciates an image by supplying light to one surface of the screen and observing light emitted from the other surface of the screen.

  DESCRIPTION OF SYMBOLS 10 Projector, 11R R light source part, 11G G light source part, 11B B light source part, 12 CGH, 13 Parallelizing lens, 14 Spatial light modulation device, 15 Projection lens, 16 Prism, 17 pixels, 18R R Light subpixel, 18G G light subpixel, 18B B light subpixel, 19 Micro lens, 21 Convex lens, AX optical axis, C center position, LR, LB chief ray

Claims (3)

A plurality of light source units that emit coherent light that is colored light in different wavelength ranges;
A diffractive optical element that diffracts the coherent light and emits the diffracted light;
A collimating lens that collimates the light beam of the diffracted light;
A spatial light modulator that modulates light incident from the collimating lens according to an image signal;
Deflection means provided for at least one of the plurality of color lights from the plurality of light source units and deflecting the light,
In any of the plurality of color lights, the incident angle and the exit angle of the principal ray in the diffractive optical element are substantially the same,
By deflecting light by the deflecting means, the plurality of color lights collimated by the collimating lens are superimposed on an irradiation area of the spatial light modulator ,
The deflecting unit includes a prism, is provided in an optical path between the diffractive optical element and the collimating lens, deflects the diffracted light incident from the diffractive optical element,
At least one of the plurality of color lights enters the collimating lens from the diffractive optical element without passing through the deflecting unit,
The projector is characterized in that the spatial light modulator is arranged by shifting the center position of the irradiation area from the optical axis of the collimating lens . Having a microlens array comprising a plurality of microlenses provided at substantially the same pitch as the pixels in the irradiation region;
The microlens array, in a two-dimensional direction to parallel the plurality of microlenses, the center position of the micro lenses, according to claim 1, characterized in that it is arranged is shifted from the center position of the pixel projector. Having a microlens array comprising a plurality of microlenses provided at substantially the same pitch as the pixels in the irradiation region;
The microlens array, in a two-dimensional direction to parallel the plurality of micro lenses, according to claim 1, wherein the center position of the microlens, characterized in that it is arranged substantially aligned with the center position of the pixel Projector.

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