JP4104578B2 - Projector device - Google Patents

Description

The present invention relates to a projection type projector apparatus that modulates light from a light source in accordance with a video signal and projects the light onto a screen.

  As a projection-type projector device, for example, a technique disclosed in Patent Document 1 below is known. In such a projector apparatus, three semiconductor lasers that emit red laser light, green laser light, and blue laser light are arranged as light sources, and each color laser light is optically modulated in accordance with a video signal, and then these are dichroic mirrored. It is synthesized and projected onto the screen with a projection lens. Light modulation of the laser light is performed using a spatial light modulator.

In addition, there is a technique in which light from a single light source is converted into three primary colors in a time-sharing manner using a flywheel, and then light-modulated according to a video signal and projected onto a screen.
Japanese Patent Laid-Open No. 11-64789

  However, according to the technique described in Patent Document 1, an optical component and a spatial light modulator are required for each of the three primary color laser beams, resulting in an increase in the number of components and an increase in cost. In addition, since it is necessary to secure an optical path for each laser beam, the size of the apparatus is increased.

  In addition, when using a flywheel, light from a single light source is converted into three primary colors in a time-sharing manner, so that the light use efficiency is reduced, causing problems such as insufficient illuminance or increased power consumption. .

Therefore, an object of the present invention is to provide a projector device that can increase the light use efficiency while suppressing an increase in the number of components and an increase in the size of the device.

  According to a first aspect of the present invention, there is provided a projector apparatus comprising: a light source; a light separating unit that separates light from the light source into three primary colors by chromatic dispersion of a prism; and a light modulating unit that modulates the separated light of each color based on a video signal. And light combining means for recombining the modulated light of each color by chromatic dispersion of the prism, and projection means for projecting the combined light on the screen.

  A projector device according to a second invention is the projector device according to the first invention, wherein the light separating means includes a group of lenses arranged in a plane and is incident on each lens out of the light incident from the light source. A first lens array that imparts a light convergence action to the partial light flux, and a first prism that separates each light flux converged by the lens array into light of three primary colors by a chromatic dispersion action, The light combining means includes a second prism that combines light of each color separated by the first prism into a light beam before separation by chromatic dispersion, and a first lens array for each of the combined light beams. It has the 2nd lens array which provides the optical effect | action which correct | amends a light convergence effect | action.

  According to a third aspect of the present invention, in the projector device according to the second aspect, the light modulation means includes a light modulation array including a group of light modulation elements arranged corresponding to the convergence positions of the light beams of the respective colors. It is characterized by that.

  According to a fourth aspect of the present invention, in the projector according to the third aspect, the light modulation array includes a shutter array that blocks the light of each color based on the video signal.

  A projector device according to a fifth invention is characterized in that, in the fourth invention, the shutter array is constituted by a liquid crystal element or a MEMS (Micro Electro Mechanical Systems) element.

  A projector device according to a sixth aspect of the present invention is the projector according to any one of the second to fifth aspects, wherein the first prism and the second prism impart a color dispersion action to the incident light flux. A saw-shaped inclined surface is formed, and the width dimension of the inclined surface is such that a predetermined number of adjacent light beams out of the group of light beams converged by the first lens array are incident on one inclined surface. It is characterized by being set.

  The features of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely an embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the following embodiment.

Note that the first prism and the second prism, which are constituent elements of the second invention, are described as the first prism array 13 and the second prism array 15 in the following embodiments.

  According to the present invention, the light from the light source is separated into the three primary colors by chromatic dispersion by the prism, and after the light of each separated color is subjected to light modulation, the light of the three primary colors is again synthesized by chromatic dispersion by the prism. Therefore, it is not necessary to prepare a semiconductor laser, its optical path, and optical system for each of the three primary colors, so that the number of parts can be reduced and the apparatus shape can be reduced.

  Further, the light use efficiency is not because light from the light source is not time-divided into three primary colors as in the prior art using the flywheel, but is divided into three primary colors by color dispersion by a prism. Is reduced, and light with sufficient illuminance can be projected onto the screen with low power consumption.

In addition, the operational effects of the present invention will be clearly understood in the description of the embodiments shown below.

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

  First, FIG. 1 shows a configuration (optical system) of a projector apparatus according to the embodiment. As shown, the projector device includes a light source 10, a collimating lens 11, a first lens array 12, a first prism array 13, a shutter array 14, a second prism array 15, and a second prism array. A lens array 16 and a projection lens 17 are included.

  The light source 10 includes, for example, a lamp that emits natural light and a reflector that efficiently guides light from the lamp forward (in the direction of the collimator lens 11). The light from the light source 10 is converted into parallel light by the collimating lens 11 and is incident on the first lens array 12.

  As shown in FIG. 2, in the first lens array 12, microlenses 121 are arranged in rows and columns so as to be adjacent to each other. The focal lengths of the micro lenses 121 are all set to be the same. Of the light incident from the collimating lens 11, the partial light beams incident on the respective microlenses 121 are converged by the microlens 121 and then incident on the first prism array 13.

  As shown in FIG. 2, the first prism array 13 includes a prism 131 and a prism 132. The prism 131 and the prism 132 are arranged to face each other with a constant interval (air). The first prism 131 has a prism surface 131a having a sawtooth cross section on the light emission side. The second prism 132 has a prism surface 132a having a sawtooth cross section on the light incident side. These prism surfaces 131a and 131b have the same shape and the inclined directions are reversed. The inclination angles of the prism surfaces 131a and 131b are all set to the same angle. The prism 131 and the prism 132 are made of the same material, and the refractive indexes of both are the same.

  FIG. 3 shows the color dispersion action by the prism surfaces 131a and 132a. In the figure, for the sake of convenience, only one prism surface of the series of prism surfaces formed on the prisms 131 and 132 is shown.

  When the partial light beam converged by the microlens 121 is incident on the prism surface 131a, the light beam is refracted by the prism surface 131a and emitted to the outside due to the difference between the refractive index in the prism 131 and the refractive index of the outside (air). The Here, since the refraction angles by the prism surface 131a differ for each wavelength, the light beams of the three primary colors of red (R), green (G), and blue (B) among natural light have different refraction angles as shown in the figure. The light is emitted to the outside (air).

  When the light beams of these three primary colors are incident on the prism surface 132a arranged to face each other, the light is refracted by the prism surface 132a. Here, since the prism surface 131a and the prism surface 132a are parallel and the refractive indexes of the prism 131 and the prism 132 are the same, the light beams of the three primary colors refracted by the prism surface 132a are parallel to each other. It travels in the same direction as the light beam incident on the prism 131.

  Due to this optical action, the light beams of the respective colors after passing through the prism 132 have fixed optical axis gaps D1 and D2. Here, the optical axis gaps D1 and D2 depend on the refractive index of the prisms 131 and 132, the refraction angle of the angular luminous flux due to the inclination angle θ of the prism surfaces 131a and 132a, and the arrangement interval D0 of the prisms 131 and 132. As the arrangement interval D0 is increased, the optical axis gaps D1 and D2 are increased.

  Returning to FIG. 1, the light beams of the three primary colors divided in this way are incident on the shutter array 14 and modulated. At this time, the light beams of the respective colors are converged by the microlens 121 as described above. The shutter array 14 is disposed in the vicinity of the convergence position of the light beams so that each shutter element can individually receive the light beams of the respective colors.

  FIG. 4 shows the light modulation action by the shutter array 14. In the figure, the positional relationship among the microlens 121, the prism 131, the prism 132, and the shutter array 14 is schematically shown. In the drawing, the red light beam is indicated by a solid line, the green light beam is indicated by a dotted line, and the blue light beam is indicated by a one-dot chain line.

  The partial light beams that have been subjected to the converging action by the microlens 121 are separated into the three primary colors by the prisms 131 and 132 as described above, and then converged on the shutter elements 141a, 141b, and 141c of the shutter array 14, respectively. The shutter elements 141a, 141b, and 141c correspond to the red pixel, the green pixel, and the blue pixel of the reproduced image frame, respectively. Each shutter element is turned ON / OFF according to the video signal. The light beams of the three primary colors are transmitted through the shutter element only while the shutter element is ON. The intensity of each pixel color is controlled by the length of the ON period of each shutter element in one frame period. The shutter elements 141a, 141b, and 141c can be configured using, for example, liquid crystal elements.

  In the figure, the width dimension of the prism surface 131a is set so that three rows of microlenses 121 are arranged corresponding to one prism surface 131a. Correspondingly, the prism surface 132a is also set to have a width dimension so that three primary color light beams for three rows are incident on one prism surface 132a. One microlens 121 is arranged corresponding to a pixel set including one shutter element 141a, 141b, and 141c. The focal length of the microlens 121 and the size of the optical axis gaps D1 and D2 between the three primary colors by the prisms 131 and 132 described above are such that the light beams of these three primary colors enter the shutter elements 141a, 141b, and 141c in one pixel set. It is adjusted and set so that it converges properly.

  Returning to FIG. 1, the light beams of the three primary colors transmitted through the shutter array 14 are combined by the second prism array 15 and returned to the original light beam. Then, the light convergence effect imparted by the first lens array 12 is corrected by the second lens array 16 disposed on the exit surface of the second prism 15 and converted into parallel light.

  The configuration of the assembly including the second prism array 15 and the second lens array 16 is the same as the configuration of the assembly including the first prism array 13 and the first lens array 12 described above. Both assemblies are arranged so as to be symmetric with respect to the light flux converging surface on the shutter array 14. As a result, the optical action introduced by the assembly composed of the first prism array 13 and the first lens array 12 is restored by the assembly composed of the first prism array 13 and the first lens array 12. .

  Accordingly, the parallel light in which the light at each pixel position is modulated by the shutter array 14 enters the projection lens 17 and is projected onto the screen. As a result, an image corresponding to the image signal is projected on the screen.

  According to the present embodiment, the light from the light source 10 is separated into the three primary colors R, G, and B by chromatic dispersion by the first prism array 13, and light modulation is applied to the separated light of each color by the shutter array 14. Then, again, the original light is synthesized by chromatic dispersion by the second prism array 15, so that the semiconductor laser, its optical path, and optical system for each of the three primary colors as in the prior art (Patent Document 1). Therefore, it is possible to reduce the number of parts and downsize the apparatus.

  In addition, since the optical path is divided into three primary colors by chromatic dispersion by the prism, the light use efficiency does not decrease as in the prior art using the flywheel, and light with sufficient illuminance with low power consumption. Can be projected onto the screen.

  Further, in the above-described embodiment, the first lens array 12 is arranged so that the light beams of the three primary colors are separated and converged on the switching elements 141a, 141b, and 141c arranged corresponding to the frame pixels. As a result, the light beams of the three primary colors can be modulated for each frame pixel, so that a high-definition image can be projected on the screen.

  As described above, according to the present embodiment, high-definition video reproduction can be realized while reducing the number of parts and cost, downsizing the device shape, and reducing power consumption.

  In the above embodiment, the shutter array 14 is a transmissive type, but it can also be configured as a reflective type. In this case, the shutter array 14 can be configured using an existing DMS (Digital Micro-mirror System) using MEMS technology.

  FIG. 5 shows a configuration example in such a case.

  In this configuration example, a surface emitting laser array 30 is used as a light source. The surface emitting laser array 30 is configured by arranging a laser element group that emits red laser light, green laser light, and blue laser light in a matrix so that laser beams of the respective colors are evenly mixed. The laser beams emitted from the respective laser elements are adjusted so that their polarization planes are parallel to each other.

  The light emitted from the surface emitting laser array 30 is incident on the polarization beam splitter (polarization BS) 21. The polarized light BS21 is adjusted so as to transmit almost all the light incident from the surface emitting laser array 30. The light transmitted through the polarization BS 21 is converted into circularly polarized light by the λ / 4 plate 22 and then incident on the first lens array 12.

  As described above, the light incident on the first lens array 12 is converged by the first lens array 12 and then separated into three primary colors by the first prism array 13, and the shutter array 23. Converged on. In the shutter array 23, as described above, shutter element groups are arranged corresponding to the pixel positions of the frame image. In this configuration example, the shutter element group is configured by a light reflection type element (DMS). The configuration of DMS is described in, for example, Japanese Patent Laid-Open No. 5-150173. DMS is a technique that is already used in a projection type projector apparatus.

  FIG. 6 shows a configuration example when the shutter array 23 is configured using DMS. In the figure, the front side of the shutter array 23 is cut away so that the configuration of one shutter element can be seen.

  In the figure, the upper surfaces of the beam portion 233 and the plate-like portions 234a and 234b are mirror surfaces 231. Further, electrodes 232a and 232b are arranged to face the pair of plate-like portions 234a and 234b.

  For example, when a plus potential is applied to the electrode 232a while keeping the pair of plate-like portions 234a and 234b at a minus potential, a Coulomb force in the attracting direction is generated between the plate-like portion 234a and the electrode 232a. At this time, when a negative potential is applied to the electrode 232b, a Coulomb force in a repulsive direction is generated between the plate-like portion 234b and the electrode 232b.

  Due to the Coulomb force, the mirror surface 231 rotates in the downward arrow direction in FIG. When a potential having a polarity opposite to that described above is applied to the pair of plate-like portions 234a and 234b, the mirror surface 231 rotates in the upward arrow direction with the beam portion 233 as an axis.

  In this way, by tilting the mirror surface 231, the reflection direction of the light converged on the mirror surface 231 can be deflected sideways.

  As described above, the shutter elements shown in the figure are arranged corresponding to the pixel positions of the frame image, and the light beams of the three primary colors are converged respectively. Therefore, the light beams of the three primary colors are reflected in the direction reverse to the incident optical path only while the shutter element is ON (while the mirror surface is not tilted), and are on the side while it is OFF (while the mirror surface is tilted). Kicked by The intensity of each pixel color is controlled by the length of the ON period of each shutter element in one frame period.

  Returning to FIG. 5, the light beams of the three primary colors reflected by the shutter array 23 are returned to the original light beam by going back in the incident optical path. That is, the light of the three primary colors is synthesized into the original light flux by going back through the first prism array 13, and returned to parallel light by going back through the first lens array 12. Further, the polarization plane is rotated by the λ / 4 plate 22 so as to be orthogonal to the polarization plane at the time of incidence, and almost totally reflected by the polarization BS21. Then, the light is projected on the screen by the projection lens 17.

  According to this configuration example, the assembly of the second prism array 15 and the second lens array 16 can be reduced as compared with the above embodiment. Since the size of one element of DMS can be made smaller than that of a liquid crystal element, the shutter array 23 can be easily reduced in size and integrated. Therefore, even if the distance D0 (see FIG. 3) between the prisms is reduced and the gaps D1 and D2 between the optical axes are reduced, the light beams of the three primary colors can be received by the corresponding shutter elements. Therefore, in this configuration example, it is possible to reduce the size of the optical system by reducing the distance D0 between the prisms. In this case, since the distance between the first lens array 12 and the shutter array 23 is reduced, the focal length of the microlens 121 arranged in the first lens array 12 can be reduced.

  In the above embodiment, a plurality of prism surfaces 131a and 132a are formed on the prisms 131 and 132. However, as shown in FIGS. 7 and 8, one prism surface 401a and 402a is provided for each prism 401 and 402. It is also possible to perform color separation of all light beams (all partial light beams converged by the microlens group) on this prism surface. In this case, the prisms constituting the second prism array 41 are similarly configured.

  In this case, since the prism surface can be easily formed as compared with the above embodiment, the manufacturing cost of the prism can be suppressed. However, in this case, since the thicknesses of the prisms constituting the first and second prism arrays are increased, the shape dimensions of the optical system are increased. In accordance with this, there also arises an inconvenience that the focal length of the microlens 121 has to be set considerably large.

  The prism thickness decreases as the number of inclined surfaces is increased to decrease the number of light beams incident on one inclined surface. Ultimately, if the width dimension of the inclined surface 131a is set so that the partial luminous flux converged by the one row of microlenses 121 is incident on one inclined surface 131a, the thickness of the prism 131 is minimized. If the width of the inclined surface 131a is reduced, the inclined surface cannot be formed smoothly, and there is a concern that the characteristics may be lowered or the manufacturing cost may be increased. The width dimension of the inclined surface 131a is appropriately set in consideration of these factors. In the above embodiment (see FIG. 4), the width dimension of the inclined surface 131a is set so that the partial light beams from the three rows of microlenses 121 are incident on one inclined surface 131a.

In addition to the above, the embodiment of the present invention can be appropriately modified in various ways within the scope of the technical idea shown in the claims.

The figure which shows the structure of the projector apparatus which concerns on embodiment The figure which shows the structure of a 1st lens array and a 1st prism array. The figure which shows the color dispersion effect | action by a 1st prism array The figure explaining the light modulation action by a shutter array The figure which shows the other structural example of the projector apparatus which concerns on embodiment The figure which shows the structure of the shutter array in the said structural example The figure which shows the further another structural example of the projector apparatus which concerns on embodiment. The figure which shows the structure of the 1st lens array in the said structure, and a 1st prism array.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Light source 12 1st lens array 13 1st prism array 14 Shutter array 15 2nd prism array 16 2nd lens array 23 Shutter array 40 1st prism array 41 2nd prism array 131a Prism surface 132a Prism surface

Claims (6)

A light source;
Light separating means for separating light from the light source into three primary colors by chromatic dispersion of the prism;
Light modulation means for modulating the separated light of each color based on the video signal;
Photosynthesis means for recombining the modulated light of each color by chromatic dispersion of the prism;
Projection means for projecting the synthesized light onto the screen;
A projector apparatus comprising: In claim 1,
The light separating means includes a first lens array that includes a group of lenses arranged in a plane and that imparts a light convergence effect to partial light beams incident on each lens out of the light incident from the light source, A first prism that separates each light beam converged by the lens array into three primary colors by chromatic dispersion;
The light combining means includes a second prism that combines light of each color separated by the first prism into a light beam before separation by chromatic dispersion action, and the first lens array for each of the combined light beams. Having a second lens array that provides an optical action to correct the light convergence effect;
A projector device characterized by that. In claim 2,
The light modulation means comprises a light modulation array comprising a group of light modulation elements arranged corresponding to the convergence positions of the light of each color,
A projector device characterized by that. In claim 3,
The light modulation array includes a shutter array that blocks the light of each color based on the video signal.
A projector device characterized by that. In claim 4,
The shutter array is configured by a liquid crystal element or a MEMS element.
A projector device characterized by that. In any of claims 2 to 5,
The first prism and the second prism are formed with a sawtooth inclined surface having a chromatic dispersion function for an incident light beam, and the group of the light beams converged by the first lens array. The width of the inclined surface is set so that a predetermined number of adjacent light beams out of the light beams are incident on one inclined surface.
A projector device characterized by that.

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