JP3150124B2 - LCD projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal projector, and more particularly to a liquid crystal projector, which separates incident light from a light source into three color components and modulates the luminous flux of each of the separated color components in accordance with image information. The present invention relates to a liquid crystal projector for optically combining and displaying images.

[0002]

2. Description of the Related Art A conventional liquid crystal projector is disclosed in
No. 60538. The liquid crystal projector described in this publication irradiates a single transmissive matrix-type liquid crystal display panel with a plurality of light beams having different wavelength ranges from different directions, and combines the plurality of light beams to perform color display on a screen. Therefore, a large-screen display is possible due to the configuration. In this liquid crystal projector, the liquid crystal display panel individually modulates each light beam transmitted at a different angle from each other. On the light emission side of the liquid crystal display panel, there is disposed an optical system for synthesizing each light beam transmitted through the liquid crystal display panel as a color image.

In the liquid crystal projector described in the above publication,
The light separating means for separating the incident light from the light source into the three primary colors of light, red, blue and green, is composed of three dichroic mirrors. The dichroic mirror includes a first dichroic mirror that reflects a red component, a second dichroic mirror that reflects a green component, and a third dichroic mirror that reflects a blue component. The first to third dichroic mirrors are fixed at a predetermined angle to each other and at a predetermined interval, and separate incident light from a light source into three color components and irradiate the liquid crystal display panel. The liquid crystal display panel modulates each color component in accordance with image information, optically synthesizes the color components with a field lens, and displays an image on a screen.

[0004]

In the above-mentioned conventional liquid crystal projector, although the luminance can be improved by irradiating the liquid crystal display panel while separating the three primary colors with three dichroic mirrors, one spot on the screen can be realized. In this case, only a single color was displayed, and a more complicated structure was required to improve the resolution.

[0005] In view of the above, it is an object of the present invention to provide a liquid crystal projector which has a simple configuration and can further improve the resolution.

[0006]

In order to achieve the above object, a liquid crystal projector according to the present invention includes light separating means for separating incident light from a light source into three color components, and the light is separated by the light separating means. In a liquid crystal projector that modulates the luminous flux of each color component according to image information and then optically synthesizes and displays the modulated luminous flux, the plurality of light separating units are arranged to be inclined at predetermined angles with respect to the incident light. Each of the dichroic mirrors is disposed at an equal angular interval with respect to the central axis, and has a reflecting / transmitting portion that reflects a specific component of the three color components and transmits another component. The plurality of dichroic mirrors rotate around a central axis synchronously with the respective reflection / transmission portions aligned in a predetermined state.

The liquid crystal projector of the present invention has a simple configuration in which each dichroic mirror is provided with reflection / transmission portions at equal angular intervals, and separates incident light in a time-division manner by synchronous rotation of a plurality of dichroic mirrors. Can be.
For example, by changing the state in response to one frame of image information signal, full-color display can be performed by time division at one spot on the screen. Obtainable.

Here, it is preferable that each dichroic mirror has a tooth surface on an outer peripheral surface, and the light separating means has a gear that meshes with the tooth surface and rotates the dichroic mirror in one direction. In this case, a mechanism for synchronously rotating a plurality of dichroic mirrors can be realized with a simple configuration.

Preferably, a total reflection mirror having a reflection surface inclined at a predetermined angle with respect to the incident light is further provided downstream of the plurality of dichroic mirrors.
In this case, for example, if two dichroic mirrors are provided, each color component transmitted through the two rotating dichroic mirrors can be reflected by the total reflection mirror.
A simpler configuration with a reduced number of dichroic mirrors can be obtained.

The liquid crystal projector according to the present invention includes light separating means for separating incident light from a light source into three color components, and modulates the luminous flux of each color component separated by the light separating means in accordance with image information. In a liquid crystal projector for optically combining and displaying images later, the light separating means has a rotation axis inclined at a predetermined angle with respect to the incident light, and has a disc-shaped optical filter which rotates about the rotation axis. A member, and a mirror member for reflecting a light beam reflected by the optical filter member in a predetermined direction, wherein the optical filter member is arranged at equal angular intervals with respect to a central axis and a specific component among the three color components is provided. First and second transmission filter portions each having three types of filters for sequentially transmitting and reflecting other components to the mirror member are provided on the inner peripheral side and the outer peripheral side, respectively; Parts are characterized by comprising adjacent to each other said filters corresponding to different specific component in the radial direction.

In the liquid crystal projector according to the present invention, the incident light is separated in a time division manner by rotating the optical filter members provided with the first and second transmission filters on the inner and outer peripheral sides with respect to the mirror member. can do. This enables full-color display by time division with one spot on the screen, so that a resolution several times higher than that of a conventional liquid crystal projector can be obtained.

[0012]

The present invention will be described in more detail with reference to the drawings. FIG. 1 is a side view showing a main configuration of a liquid crystal projector according to the first embodiment of the present invention.

The liquid crystal projector has a light source 10 such as a halogen lamp or a xenon lamp, a light separating means 28, a liquid crystal display panel 25, a field lens 26, and a projection lens 27. The light separating means 28 separates incident light from the light source 10 into three primary colors of red, green and blue light.
The liquid crystal display panel 25 is configured as a matrix transmission type, is inserted in the optical path of each color component separated by the light separating means 28, and modulates the luminous flux of three kinds of color components in accordance with input image information. . The field lens 26
The three color components transmitted through the liquid crystal display panel 25 are optically combined. The projection lens 27 displays the three color components synthesized by the field lens 26 on a screen (not shown).

The light separating means 28 comprises four dichroic mirrors 11, 12, 1 for separating and reflecting incident light in a time-division manner.
3 and 14. The dichroic mirrors 11 to 14 have the same radius as each other, are each configured in a disk shape having a tooth surface on each outer peripheral surface, and rotate in synchronization with each other about rotation axes 15 to 18. Each of the rotation axes 15 to 18 is inclined at a predetermined angle with respect to the optical axis of the incident light.
Are set to gradually decrease in this order. Thereby, the dichroic mirrors 11 to 14
It gradually rises in this order with respect to the optical axis of the incident light.

A motor 19 is provided below the dichroic mirrors 11 to 14. The motor 19 has a long rotating shaft 20 inclined at a predetermined angle with respect to the optical axis of the incident light. The rotating shaft 20 is provided at predetermined intervals with the gears 21, 2
2, 23 and 24 are fixed. The gears 21 to 24 have the same diameter, and the gear 21 meshes with the dichroic mirror 11, the gear 22 meshes with the dichroic mirror 12, the gear 23 meshes with the dichroic mirror 13, and the gear 24 meshes with the dichroic mirror 14.

FIG. 2 is a front view showing the dichroic mirror in this embodiment in detail. The dichroic mirror 11 reflects an R reflection portion (reflection / transmission portion) 11a that reflects red light (red component) and transmits other color components, and reflects blue light (blue component) and transmits other color components. The B reflecting portion 11b and the transmitting portion 11c that transmits all color components are arranged while being divided by 120 ° clockwise with respect to the rotation axis 15 (center axis). The dichroic mirror 12 includes a G reflector 12a that reflects green light (green component) and transmits other color components, an R reflector 12b similar to the R reflector 11a,
The B-reflecting portion 12c similar to the B-reflecting portion 11b is
6 are arranged in a clockwise direction by 120 °.

The dichroic mirror 13 includes a B reflector 13a similar to the B reflector 11b, a G reflector 13b similar to the G reflector 12a, and an R reflector 13c similar to the R reflector 11a. 120 ° clockwise about axis 17
Are divided and arranged. Dichroic mirror 14
Is divided into three regions by 120 ° around the rotation axis 18, but the R reflection portion 13 c of the dichroic mirror 13
, Only the G reflecting portion 14c is arranged. In the other areas 14a and 14b, neither the reflection part nor the transmission part is arranged.

The dichroic mirrors 11 to 1 having the above configuration
Numeral 4 respectively meshes the tooth surfaces of the respective outer peripheral surfaces with the gears 21 to 24, and rotates while maintaining the positional relationship shown in FIG. Each reflection part 11a, 11
b, 12a to 12c, 13a to 13c, and 14c, the tilt angles of the dichroic mirrors 11 to 14 are adjusted so that the reflected lights converge on the same spot on the liquid crystal display panel 25.

FIGS. 3 to 5 are enlarged sectional views showing the liquid crystal display panel 25, respectively. The liquid crystal display panel 25 has a transparent member 33 on the dichroic mirror side and a transparent panel 31 on the field lens 26 side.
And a liquid crystal panel 32 between them. Transparent panel 33
A plurality of micro lenses 34 are fixed to the dichroic mirror side.

By rotating the dichroic mirrors 11 to 14, the following reflection state is obtained. In the first reflection state, the dichroic mirror 11 and the dichroic mirror 12 correspond to the R reflection portion 11a and the G reflection portion 12 with respect to the incident light, respectively.
a, the dichroic mirror 13 positions the B reflecting portion 13a, and the dichroic mirror 14 positions the region 14a.
In this state, as shown in FIG. 3, the red light (R), the green light (G), and the blue light (B) ), R, G, B... As a result, the luminous flux of each color component is overfocused by the microlens 34, and enters the liquid crystal element 32a in the order of blue light, green light, and red light.

In the second reflection state, the dichroic mirror 11 reflects the B reflection portion 11b, the dichroic mirror 12 reflects the R reflection portion 12b, the dichroic mirror 13 reflects the G reflection portion 13b, and the dichroic mirror 14 reflects the incident light with respect to the incident light. Position each one. In this state, as shown in FIG. 4, light enters the microlens 34 in the order of B, R, G,. As a result, the luminous flux of each color component is overfocused by the microlens 34, and enters the liquid crystal element 32a in the order of green light, red light, and blue light.

In the third reflection state, the dichroic mirror 11 is a transmitting portion 11c, the dichroic mirror 12 is a B reflecting portion 12c, the dichroic mirror 13 is an R reflecting portion 13c, and the dichroic mirror 14 is a G light.
The reflecting portions 14c are located respectively. In this state, as shown in FIG.
B, R, G ...
Incident in this order. As a result, the luminous flux of each color component is overfocused by the microlens 34, and enters the liquid crystal element 32a in the order of green light, red light, and blue light. In this case, the order of the color components incident on the liquid crystal display panel 25 is the second order.
However, in the third reflection state, the light is transmitted through the transmission portion 11c one step and then reflected in the same color order as in the second reflection state, so that the incident angle with respect to the liquid crystal display panel 25 is the second angle. Is different from the reflection state.

In this embodiment, when the motor 19 rotates, the dichroic mirrors 11 to 14 rotate while maintaining the positional relationship of FIG. 2, so that the dichroic mirrors 11 to 14 in FIG. Each reflection state transitions. Accordingly, the present liquid crystal projector divides the incident light from the light source 10 into three primary colors in a time-division manner while having a simple configuration in which each of the dichroic mirrors 11 to 14 is provided with a reflection portion and a transmission portion at equal angular intervals. Thus, full color display by time division can be obtained at one spot on the screen (not shown). For this reason, according to the present liquid crystal projector, a large screen, high resolution and high brightness can be obtained, television images (moving images) can be displayed, and a conventional liquid crystal projector having no dichroic mirrors at equal angular intervals. About three times the resolution can be obtained.

In the present embodiment, the dichroic mirror 14 can be replaced with a total reflection mirror. In this case, the same effect as in the case where the dichroic mirror 14 is used can be obtained.

Next, a second embodiment of the present invention will be described. FIG. 6 is a side view illustrating a configuration of a main part of the liquid crystal projector according to the present embodiment. In the first embodiment, the light is separated using four dichroic mirrors. In the present embodiment, the light is separated using two dichroic mirrors and one total reflection mirror. In the figure, the field lens and the projection lens are not shown.

The light separating means 38 in this embodiment is
Dichroic mirrors 12, 13 and total reflection mirror 29
Having. The dichroic mirrors 12 and 13 are supported by rotating shafts 16 and 17 at a predetermined angle with respect to the incident light. Dichroic mirrors 12 and 13
Is the dichroic mirror 12 in the first embodiment.
13 has the same configuration as that of the first embodiment, and the tooth surfaces provided on the outer peripheral surface are engaged with the gears 22 and 23 provided on the rotating shaft 20 similar to the first embodiment. Dichroic mirror 1
A total reflection mirror 29 is provided at a stage subsequent to 2 and 13. 2
The reflecting portions of the dichroic mirrors 12 and 13 and the reflecting surface of the total reflection mirror 29 are set at angles at which the light flux separated from the incident light is reflected toward the liquid crystal display panel 25.

FIG. 7 is a front view showing the dichroic mirror in this embodiment in detail. In FIG. 1, for convenience, the G reflecting portion 12a of the dichroic mirror 12 is a region that reflects green light, but the dichroic mirror that reflects green light actually reflects not only green light but also red light. In this case, there is no inconvenience in the G reflecting portion 12a of the dichroic mirror 12 in the first embodiment, since the R reflecting portion 11a is located at the preceding stage. However, in the present embodiment, since the G reflecting portion 12a is located at the forefront on the incident side, when the G reflecting portion 12a and the B reflecting portion 13a enter, the red light is transmitted through the reflecting portions 12a and 13a. Must reach the total reflection mirror 29. To realize this, the G reflection section 12a in the present embodiment is configured to reflect only green light.

FIG. 8 is a sectional view showing the liquid crystal display panel 25 in an enlarged manner. The liquid crystal display panel 25 has the same configuration as the first embodiment. Dichroic mirror 1
The next reflection state is obtained by the synchronous rotation of 2, 13 at 120 ° each.

In the first reflection state, the dichroic mirror 12 positions the G reflection portion 12a and the dichroic mirror 13 positions the B reflection portion 13a with respect to the incident light. In this state, as shown in FIG.
The green light, the blue light, the red light,...
Incident in this order. As a result, each light beam is
The light is overfocused at 4, and is incident on each liquid crystal element 32a in the order of red light, blue light, and green light.

In the second reflection state, the dichroic mirror 12 positions the R reflection portion 12b and the dichroic mirror 13 positions the G reflection portion 13b with respect to the incident light. In this state, red light, green light, blue light,... Are incident on the microlens 34 in this order from the near side in the incident direction of the light from the light source 10. As a result, each light beam is overfocused by the micro lens 34, and each liquid crystal element 32a
, Blue light, green light, and red light in this order.

In the third reflection state, the dichroic mirror 12 positions the B reflection portion 12c and the dichroic mirror 13 positions the R reflection portion 13c with respect to the incident light. In this state, the blue light, the red light, the green light, and so on are incident on the microlens 34 from the near side in the incident direction of the light from the light source 10. As a result, each light beam is overfocused by the micro lens 34, and each liquid crystal element 32a
, Green light, red light, and blue light in this order. According to the present embodiment described above, it is possible to obtain a liquid crystal projector that can improve the resolution with a simpler configuration than the first embodiment.

Next, a third embodiment of the present invention will be described. FIG. 9 is a side view illustrating a main configuration of the liquid crystal projector according to the present embodiment. In the present embodiment,
Instead of a plurality of dichroic mirrors, light is separated using one optical filter and a total reflection mirror. The liquid crystal projector includes one optical filter 40 whose rotation axis is inclined at a predetermined angle with respect to the incident light 39 from the light source, and a total reflection mirror 41 that guides the reflected light from the optical filter 40 to the liquid crystal display panel 25. Prepare.

FIG. 10 is a front view showing the structure of the optical filter in detail. The optical filter 40 has a disk shape as a whole, and includes a first transmission filter 43a that transmits only blue light and a first transmission filter 44a that transmits only green light on an inner peripheral side around the rotation axis 42. And the first transmission filter 45a that transmits only red light at equal angular intervals in a counterclockwise direction. Further, on the outer peripheral side of the optical filter 40, a second transmission filter 43b transmitting only blue light, a second transmission filter 44b transmitting only green light, and a second transmission filter 45b transmitting only red light are provided. They are arranged counterclockwise at equal angular intervals. The second transmission filters 43b to 45b are arranged to be displaced by 120 ° counterclockwise with respect to the first transmission filters 43a to 45a, respectively. Thereby, the first transmission filters 43a to 45a and the second transmission filter 4
Portions corresponding to different specific components among 3b to 45b are adjacent to each other in the radial direction.

As shown in FIG. 9, the total reflection mirror 41 is
A first reflection surface 41a that totally reflects the light fluxes respectively reflected on the back surfaces of the first transmission filters 43a to 45a to each of the second transmission filters 43b to 45b;
and a second reflection surface 41b for guiding the light fluxes respectively reflected on the back surfaces of b to 45b to the liquid crystal display panel 25. First reflective surface 4
1a shows a part of the totally reflected light beam as a second transmission filter 43.
liquid crystal display panel 2 after transmitting any one of
5, the tilt angle is adjusted so that the light beam reflected on any of the back surfaces of the second transmission filters 43b to 45b is directed to the second reflection surface 41b.

In the liquid crystal projector according to the present embodiment, when the incident light 39 enters while the optical filter 40 is rotated in one direction about the rotation axis 42 by the motor,
It works as follows. For example, the first transmission filter 45
a and the second transmission filter 44b reach the incident position, the red light transmitted through the first transmission filter 45a enters the liquid crystal display panel 25, and the luminous flux reflected on the back surface of the first transmission filter 45a becomes the first reflection surface. The light is further reflected at 41a and travels to the second transmission filter 44b. At this time, the green light passes through the second transmission filter 44b and goes to the liquid crystal display panel 25,
Further, the light beam reflected on the back surface of the second transmission filter 44b is further reflected on the second reflection surface 41b, and travels toward the liquid crystal display panel 25 as blue light from which red light and green light have been removed.
Hereinafter, even when another transmission filter is positioned with respect to the incident light 39, the same operation as described above is performed.

Although the present invention has been described based on the preferred embodiment, the liquid crystal projector of the present invention is not limited to the configuration of the above-described embodiment, and is not limited to the configuration of the above-described embodiment. A liquid crystal projector with various modifications and changes is also included in the scope of the present invention.

[0037]

As described above, according to the liquid crystal projector of the present invention, the resolution can be further improved while having a simple structure.

[Brief description of the drawings]

FIG. 1 is a side view showing a main configuration of a liquid crystal projector according to a first embodiment of the present invention.

FIG. 2 is a front view showing a dichroic mirror in the first embodiment in detail;

FIG. 3 is an enlarged sectional view showing a liquid crystal display panel.

FIG. 4 is an enlarged sectional view showing a liquid crystal display panel.

FIG. 5 is an enlarged sectional view showing a liquid crystal display panel.

FIG. 6 is a side view illustrating a main configuration of a liquid crystal projector according to a second embodiment of the present invention.

FIG. 7 is a front view showing a dichroic mirror in a second embodiment in detail;

FIG. 8 is an enlarged cross-sectional view illustrating a liquid crystal display panel according to a second embodiment.

FIG. 9 is a side view illustrating a main configuration of a liquid crystal projector according to a third embodiment of the present invention.

FIG. 10 is a front view showing in detail a structure of an optical filter according to a third embodiment.

[Explanation of symbols]

 10: Light source 11 to 14: Dichroic mirror 11a: R reflection part 11b: B reflection part 11c: Transmission part 12a: G reflection part 12b: R reflection part 12c: B reflection part 13a: B reflection part 13b: G reflection part 13c: R reflection part 14c: G reflection part 14a, 14b: area 15-18: rotation axis 19: motor 20: rotation axis 21-24: gear 25: liquid crystal display panel 26: field lens 27: projection lens 28, 38: light separation Means 39: incident light 40: optical filter 41: total reflection mirror 41a: first reflection surface 41b: second reflection surface 42: rotation axis 43a to 45a: first transmission filter 43b to 45b: second transmission filter

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G02F 1/1335 G02B 26/00 G02F 1/13 505

Claims (4)

(57) [Claims] 1. A light separating means for separating incident light from a light source into three color components, wherein the light flux of each color component separated by the light separating means is modulated in accordance with image information and then optically combined. In the liquid crystal projector, the light separating means includes a plurality of disk-shaped dichroic mirrors each arranged at a predetermined angle with respect to the incident light, and each dichroic mirror is arranged with respect to a center axis. A plurality of dichroic mirrors arranged at predetermined intervals to reflect specific components of the three color components and transmit other components; A liquid crystal projector characterized in that the liquid crystal projector rotates about a central axis in a synchronized state. 2. The apparatus according to claim 1, wherein each of the dichroic mirrors has a tooth surface on an outer peripheral surface, and the light separating means has a gear meshing with the tooth surface to rotate each of the dichroic mirrors in one direction. The liquid crystal projector as described. 3. The liquid crystal according to claim 1, further comprising a total reflection mirror having a reflection surface inclined at a predetermined angle with respect to the incident light, subsequent to the plurality of dichroic mirrors. projector. 4. A light separating means for separating incident light from a light source into three color components, wherein the light flux of each color component separated by the light separating means is modulated according to image information and then optically combined. A liquid crystal projector, wherein the light separating means has a rotation axis inclined at a predetermined angle with respect to the incident light, and a disk-shaped optical filter member that rotates about the rotation axis; A mirror member for reflecting a light beam reflected by the filter member in a predetermined direction, wherein the optical filter member is arranged at equal angular intervals with respect to a central axis, and sequentially transmits a specific component among the three color components, and Are provided on the inner peripheral side and the outer peripheral side, respectively, having three types of filters for reflecting the component on the mirror member, respectively. To the component A liquid crystal projector comprising a plurality of corresponding filters radially adjacent to each other.