JP2006184588A - Image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display apparatus capable of being easily made small in size by adjusting the length in the optical axis direction of a projection optical system. <P>SOLUTION: The image display apparatus comprises: a light source; a condenser mirror which forms a virtual secondary light source; a color filter which creates three primary colors of light from white color light with the lapse of time; a light tunnel to which a light ray passing through the color filter is made incident; a relay lens; a reflection member; a reflective display element provided with a plurality of micromirrors which change independent of one another and are arranged in a matrix on a substrate, whereby being turned on and turned off; and a projection optical system which enlarges and projects the incident light. Therein, the angle between: either of an optical axis of the light tunnel or a straight line parallel to the optical axis which intersects the optical axis of a front group of the projection optical system; and the optical axis of the front group of the projection optical system is substantially perpendicular. The light tunnel is located at a position which corresponds to a gap between a rear group of the projection optical system and the reflection member in the direction parallel to the optical axis of the front group of the projection optical system, and is not on the optical path of the projection optical system. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image display device using a plurality of micromirrors arranged on a matrix and capable of changing the emission angle of reflected light.

  As an image display device using micromirrors arranged on a matrix, each of which can independently select incident (on state) or non-incident (off state) to the projection lens by changing the emission angle Conventionally, for example, there is the one shown in FIG.

  In this image display device, the light emitted from the condensing mirror 110 in the horizontal direction (left-right direction in FIG. 7) enters the light tunnel 113 through the cover glass 111 and the color wheel 112. The light emitted from the light tunnel 113 is reflected by being bent 90 degrees in the horizontal plane by the mirror 121 through the relay lens group 120. The reflected light is reflected by the mirror 122 in a direction that forms an angle of 45 degrees with respect to the horizontal plane (the direction from the lower left to the upper right in FIG. 7), passes through the relay lens 123, and enters the prism 124. This incident light is reflected by the inner surface of the prism 124 and enters the reflective display element 130.

The reflective display element 130 includes a plurality of micromirrors (not shown) arranged on a matrix. These micromirrors change the emission angle of the reflected light by independently changing the inclination, so that the on state in which the light enters the front group of the projection optical system 150 and the reflected light is emitted in a direction different from the on state. Any of the off states can be taken. In the mirror 140, the light beam that has passed through the front group of the projection optical system 150 is reflected in the vertical direction (vertical direction in FIG. 7) and enters the rear group of the projection optical system 150. By switching on and off as described above, a desired image can be projected and displayed by the projection optical system 150.
JP 08-146911 A

  However, in the above-described image display device, in the vertical direction (the optical axis direction of the projection optical system), the rear group of the projection optical system 150 is located above the reflective display element 130, and the condenser mirror 110, the light tunnel 113, A relay lens group 120, a mirror 121, and a mirror 122 are arranged. For this reason, even if the configuration of the projection optical system 150 is devised, the vertical size of the image display device is at least the vertical length of the projection optical system 150, the condenser mirror 110, the light tunnel 113, and the relay lens group. 120, the mirror 121, and the vertical size of the mirror 122 must be combined with each other, and the request for downsizing of the image display apparatus cannot be met.

  In order to solve the above problems, in the image display device of the present invention, a light source, a condensing mirror for condensing light rays from the light source to create a virtual secondary light source, and white light emitted from the condensing mirror A color filter that produces the three primary colors of light from time to time, a light tunnel through which light rays that have passed through the color filter enter, a relay lens through which light rays that have passed through the light tunnel pass, and a reflection that reflects light emitted from the relay lens A member and a plurality of micromirrors arranged in a matrix on the substrate are provided, and the micromirrors are turned on and off by changing the angle of reflected light to change the angle of reflected light. Are divided into a front group and a rear group in order from the reflective member side by a reflective display element on which the reflected light from the reflective member is incident and a folding mirror disposed in the middle of the optical path. A projection optical system for projecting the incident light reflected by a small mirror and enlarging the incident light, and the optical axis of the light tunnel or a straight line parallel to the optical axis before the projection optical system. The angle between the optical axis of the optical system of the group and the optical axis of the front group of the projection optical system is substantially perpendicular, and the light tunnel is in the direction parallel to the optical axis of the front group of the projection optical system. It is characterized in that it is disposed at a position corresponding to the gap between the rear group of the system and the reflecting member and not on the optical path of the projection optical system.

  The reflection member is preferably a total reflection prism.

  The reflection member may be a reflection mirror.

  The micromirror can be turned on and off by changing the emission angle of reflected light by changing the inclination in the long side direction with the short side direction of the substrate as the rotation axis. On the other hand, the on-state and the off-state can be created by changing the emission angle of the reflected light by changing the inclination in the short-side direction with the long-side direction of the substrate as the rotation axis.

The micromirror can be turned on and off by changing the angle of reflection of the reflected light by changing the inclination in the other diagonal direction with the diagonal direction of the square micromirror as the rotation axis. it can.

  According to the present invention, by adjusting the length of the rear group of the projection optical system in the optical axis direction, the size of the image display device in this direction can be changed, so that the size of the image display device can be easily reduced. Can be realized.

  Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. As shown in FIGS. 1 to 5, the image display apparatus according to the present embodiment includes a condenser mirror 10, a light tunnel 20, relay lenses 13, 14, 15, mirrors (reflective members) 30, 31, and prisms (reflective members). ) 32, the reflective display element 40, and the projection optical system 50. In this image display device, the light emitted from the condensing mirror 10 travels in the horizontal direction (H direction in FIGS. 1 to 4), but this traveling direction may be a direction other than the horizontal direction. The image display device of the invention can be realized.

  The condensing mirror 10 has a configuration in which the light tunnel 20 side is open, and a white light source is disposed therein. As the white light source, for example, a halogen lamp, a xenon lamp, a metal halide lamp, or an ultrahigh pressure mercury lamp can be used. The light emitted radially from the white light source is reflected and collected by the inner surface of the condenser mirror 10 and is emitted toward the color wheel 12 through the cover glass 11.

For example, as shown in FIG. 6, the color wheel 12 may be a disk-shaped substrate in which RGB three-color filters 12 b to 12 d are arranged at equal angular intervals with respect to the rotation axis 12 a. . When light is irradiated from the condenser mirror 10 to a certain position on the color wheel 12 while rotating the color wheel 12 at a constant speed, R is changed at each time interval corresponding to the RGB filter arrangement interval (over time). (Red), G (green), and B (blue) light are emitted toward the light tunnel 20.

The light tunnel 20 emits light having a uniform amount of light from the other end (outgoing end) by totally reflecting light incident from one end (incident end) of the cylindrical shape on the inner surface. It is something that can be done. The light emitted from the light tunnel 20 is emitted toward the mirror 30 via the relay lens 13.

  The mirror 30 has a flat plate shape, and light emitted from the light tunnel 20 is orthogonal to the horizontal plane (vertical direction (the V direction in FIGS. 1 and 3)) through the relay lens group 14 toward the mirror 31 by this plane. Reflected in such a manner that the traveling direction is bent approximately 90 degrees within the plane.

  The mirror 31 has a flat plate shape, and the light reflected by the mirror 30 and incident through the relay lens group 14 is approximately 45 with respect to the horizontal plane toward the relay lens 15 disposed immediately before the prism 32. It is reflected in a direction forming an angle of degrees (a direction from the upper right to the lower left in FIG. 1).

  As shown in FIG. 5, after the relay lens 15 arranged on the incident side, the prism 32 has a triangular prism-shaped optical member 32b and a slope 32c1 on the slope 32b2 of the optical member 32b with an air interval of 10 microns or less. And a fixed triangular prism-shaped optical member 32c. The light incident on the relay lens 15 passes through the lens 15 and enters the optical member 32b, and is totally reflected toward the reflective display element 40 by the inclined surface 32b2. The light reflected by the reflective display element 40 passes through the inclined surface 32b2 and enters the optical member 32c.

The reflective display element 40 is a semiconductor element provided with a plurality of micromirrors arranged in a matrix on a substrate. In the reflective display element 40, the inclination of each of the plurality of micromirrors is independently changed, and the emission angle of the reflected light is independently changed, so that the reflected light is emitted toward the relay lens 15. Any of the off states in which the reflected light is emitted in a direction different from the on state can be taken. The change of the emission angle is made by swinging in the long side direction or the short side direction with the short side or long side direction of the rectangular substrate on which the micromirror is arranged as the rotation axis. Alternatively, the micromirror is formed in a square shape, and one diagonal direction thereof is used as a rotation axis, and the micromirror is swung in the other diagonal direction. In this embodiment, a reflective display element having a diagonal direction as a rotation axis is used.

For example, when a digital micromirror device (DMD) manufactured by Texas Instruments is used as such a reflective display element 40, the angle of the micromirror is +12 degrees and -12 degrees with respect to the horizontal state in this device. Therefore, it is possible to take two states as the emission angle of the light reflected by this micromirror. When light reflected by the inclined surface 32b2 is incident on the reflective display element 40 having such a configuration, the light reflected by the minute mirror in the on state (+12 degrees) is directed toward the front group 51 of the projection optical system. The light reflected by the micro mirror in the off state (−12 degrees) is emitted in a direction different from that of the front group 51 of the projection optical system. Accordingly, the light reflected by the micro mirror in the on state is finally enlarged and projected on the screen via the rear group 52 of the projection optical system, and the light reflected by the micro mirror in the off state is projected on the screen. Therefore, it is possible to display a desired image on the screen by performing on / off control of the micromirrors arranged in a matrix.

The front group 51 of the projection optical system is arranged in a direction substantially orthogonal to both the horizontal direction and the vertical direction. The light incident on the front group 51 of the projection optical system from the prism 32 passes through the front group 51 of the projection optical system and then enters the flat plate-shaped mirror 33. The mirror 33 reflects the light incident from the front group 51 of the projection optical system so as to travel toward the rear group 52 of the projection optical system.

  The rear group 52 of the projection optical system enlarges and projects the light reflected by the mirror 33 onto a screen (not shown). The light reflected by each micromirror corresponds to a pixel on the screen, and the light of the three primary colors is projected over time for each pixel, thereby controlling on / off of each micromirror as desired on the screen. Color images can be displayed.

In the present embodiment, an angle formed by a straight line parallel to the optical axis 20a of the light tunnel 20 that intersects the optical axis 51a of the front group 51 of the projection optical system and the optical axis 51a of the front group 51 of the projection optical system. Is almost vertical. The light tunnel 20 is a position corresponding to the gap between the rear group 52 of the projection optical system and the prism 32 in a direction parallel to the optical axis 51a of the front group 51 of the projection optical system, and It is arrange | positioned in the position which is not on an optical path (refer FIG. 4). Further, when the light tunnel 20 and the projection optical system 50 are projected onto a plane including both the horizontal direction and the vertical direction (orthogonal plane in a direction perpendicular to both), the light tunnel 20 is optical axis of the rear group 52 of the projection optical system. 52a (see FIG. 1). By configuring the positional relationship between the light tunnel 20 and the projection optical system 50 as described above, the vertical size of the image display device can be determined by the configuration from the mirror 33 to the rear group 52 of the projection optical system. it can. In other words, the vertical size of the image display device is less limited by the configuration of the light source 10, the cover glass 11, the color wheel 12, and the relay lens 13. Therefore, by configuring the projection optical system 50 so as to shorten the length of the rear group 52 of the projection optical system in the direction of the optical axis 52a, the image display device can be reduced in the vertical direction, and thus the image display device. The whole can be configured compactly.

Although the present invention has been described with reference to the above embodiment, the present invention is not limited to the above embodiment, and can be improved or modified within the scope of the purpose of the improvement or the idea of the present invention.

It is a perspective view which shows the structure of the image display apparatus which concerns on embodiment of this invention. FIG. 2 is a perspective view illustrating a configuration of an image display device according to an embodiment of the present invention, which is obtained by rotating FIG. 1 by 90 degrees around the optical axis of the condenser mirror. FIG. 3 is a perspective view illustrating a configuration of an image display device according to an embodiment of the present invention, which is obtained by rotating FIG. 2 by 90 degrees around the optical axis of the condenser mirror. FIG. 4 is a perspective view showing a configuration of an image display device according to an embodiment of the present invention, in which FIG. 3 is rotated 90 degrees around the optical axis of the condenser mirror. It is a general-view figure which shows the structure of the image display apparatus which concerns on embodiment of this invention, ignoring the reflection in each mirror, and developing in two dimensions. It is a top view which shows the structure of the color filter which concerns on embodiment of this invention. It is a perspective view which shows the structure of the conventional image display apparatus.

Explanation of symbols

10 Condensing mirror 20 Light tunnel 30 Mirror (reflective member)
31 mirror (reflective member)
32 Prism (reflective member)
40 reflective display element 50 projection optical system

Claims (6)

A light source;
A condensing mirror that condenses the light from the light source to create a virtual secondary light source;
A color filter that produces three primary colors of light over time from white light emitted from the condenser mirror;
A light tunnel into which the light beam that has passed through the color filter is incident;
A relay lens through which the light beam exiting the light tunnel passes,
A reflecting member that reflects the light emitted from the relay lens;
Provided with a plurality of micromirrors arranged in a matrix on the substrate, each of the plurality of micromirrors creates an on state and an off state by changing the inclination angle independently and changing the emission angle of the reflected light, A reflective display element on which reflected light from the reflective member is incident;
By a folding mirror disposed in the middle of the optical path, the light is divided into a front group and a rear group in order from the reflecting member side, and the on-state reflected light from the plurality of micromirrors enters, and the incident light is enlarged and projected. A projection optical system,
An angle formed by an optical axis of the light tunnel or a straight line parallel to the optical axis that intersects the optical axis of the front group of the projection optical system and an optical axis of the front group of the projection optical system is substantially vertical. An image display device,
The light tunnel is a position corresponding to a gap between the rear group of the projection optical system and the reflecting member in a direction parallel to the optical axis of the front group of the projection optical system, and is not on the optical path of the projection optical system. An image display device characterized by being arranged at a position. The image display device according to claim 1, wherein the reflection member is a total reflection prism. The image display apparatus according to claim 1, wherein the reflection member is a reflection mirror. 4. The micro mirror according to claim 1, wherein the micromirror is turned on and off by changing a tilt angle in a long side direction and changing an emission angle of reflected light with a short side direction of the substrate as a rotation axis. 2. An image display device according to item 1. 4. The micro mirror according to claim 1, wherein the micro mirror is turned on and off by changing a tilt angle in a short side direction and changing an emission angle of reflected light with a long side direction of the substrate as a rotation axis. 2. An image display device according to item 1. The micro mirror has an on-state and an off-state by changing the emission angle of reflected light by changing the inclination in the other diagonal direction with the diagonal direction of the square micro-mirror as a rotation axis. The image display apparatus of any one of 1-3.

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