JP2009069175A - Light projection part of image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light projection part of image display device capable of correcting deviations of position, angle etc. of arrangement relation of a light emission part, a reflection type liquid crystal display part and a polarization separation part which occur upon the assembling and, thereby, minutely adjusting them into the optimum arrangement relation. <P>SOLUTION: The light projection part 2 of an image display device 1 is made by arranging the polarization separation part (PBS) 5 between the light emission part 3 and the reflection type liquid crystal display part (LCOS) 4. The light projection part 2 is configured such that a P-polarized light component in light emitted from the light emission part 3 is transmitted by a slant face 51 of the PBS 5, thereafter, is reflected by the LCOS 4 and is made to be an S-polarized light component and the S-polarized light component is reflected by the slant face 51 of the PBS 5 to be guided to a lens 11. The light projection part 2 has an adjustment means 6 which, by relatively moving any one of the light emission part 3, LCOS 4 and PBS 5 with respect to the remaining two, adjusts the arrangement relation of the both. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light projecting unit of an image display device using a light emitting unit, a reflective liquid crystal display unit, and a polarization separation unit.

In an image display device such as a projector that performs liquid crystal display, a device using a light emitter, a reflective liquid crystal display element (LCOS), and a polarizing beam splitter (PBS) is used. is there.
For example, in the image display device of Patent Document 1, only light having a predetermined polarization component is reflected by a polarization separation element, led to a reflective liquid crystal display element, and modulated and reflected according to predetermined image information. It is disclosed that light having a polarization component orthogonal to a predetermined polarization component is transmitted through a polarization separation element and guided to an observer's pupil via an eyepiece optical system. For example, Patent Document 2 discloses an LED light source projector optical system using an LED light source, a polarization beam splitter, and LCOS.

  However, the conventional image display device described above has means for adjusting the mutual arrangement relationship of the light emitting unit, the reflective liquid crystal display unit (LCOS, etc.) and the polarization separation unit (PBS, etc.) constituting the light projecting unit that is the video engine. I don't have it. Therefore, when assembling the light projecting unit, or when adjusting the light projecting unit after assembly, etc., fine adjustment of the projected image is not possible, and it is not enough to set the light projecting unit to the optimum state Absent.

JP 2004-45787 A JP-A-2005-140847

  The present invention has been made in view of such conventional problems, and corrects misalignment of the position, angle, etc. of the arrangement relationship of the light emitting section, the reflective liquid crystal display section, and the polarization separation section that occur during assembly, etc. An object of the present invention is to provide a light projecting unit of an image display device that can finely adjust these to an optimal arrangement relationship.

The present invention comprises a light emitting unit, a reflective liquid crystal display unit, and a polarization separating unit,
The first polarized component in the light emitted from the light emitting unit is transmitted or reflected by the polarized light separating unit, and then reflected by the reflective liquid crystal display unit to be a second polarized component, and the second polarized component is In the light projecting unit of the image display device configured to be reflected or transmitted by the polarization separating unit,
There is an adjusting means that adjusts the positional relationship between the light emitting unit, the reflective liquid crystal display unit, and the polarization separation unit by moving relative to the other two. It is in the light projection part of the image display apparatus characterized by the above-mentioned (Claim 1).

In the light projecting unit of the image display device of the present invention, the adjusting unit moves any one of the light emitting unit, the reflective liquid crystal display unit, and the polarization separating unit relative to the remaining two. The arrangement relationship between the two can be adjusted. Thereby, when assembling the light projecting unit or adjusting the light projecting unit after assembly, the positional relationship between the light emitting unit, the reflective liquid crystal display unit, and the polarization separating unit is shifted in position, angle, and the like. Even at this time, it is possible to correct the deviation of the position, the angle, etc., and finely adjust these to the optimum arrangement relationship for clearly displaying the video.
Therefore, according to the light projecting unit of the image display device of the present invention, the positional relationship between the light emitting unit, the reflective liquid crystal display unit, and the polarization separating unit, which occurs during assembly, etc. These can be finely adjusted to an optimal arrangement relationship.

A preferred embodiment of the present invention described above will be described.
The adjusting means may be structured to move the light emitting unit relative to the reflective liquid crystal display unit and the polarization separating unit fixed to a housing or the like. Further, the adjusting means may be structured to move the reflective liquid crystal display unit and the polarization separation unit with respect to the light emitting unit fixed to a housing or the like. In addition to the above, the adjusting means moves any one of the light emitting unit, the reflective liquid crystal display unit, and the polarization separating unit relative to the remaining two in various patterns. be able to.

The light emitting unit is preferably a light emitting diode (LED). In this case, the light emitting unit can be reduced in size, weight, and power consumption.
In the polarization separation unit, a polarization filter (polarization conversion element) can be disposed on an incident surface on which light is incident from the light emitting unit. In this case, the use efficiency can be improved by converting the light of the light emitting unit to only the necessary polarized light by the polarizing filter.

  In addition, a light tunnel in which a passage cross-sectional area for allowing light to pass through as the distance from the light emitting unit increases can be disposed between the light emitting unit and the polarization separating unit. Further, a condensing lens can be used instead of the light tunnel between the light emitting unit and the polarization separating unit.

Hereinafter, embodiments of the light projecting unit of the image display apparatus according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 and 2, the light projecting unit 2 (video engine) of the image display apparatus 1 of the present example includes a light emitting unit 3 that emits light, and a reflective liquid crystal display unit (LCOS) that reflects light and displays an image. ) 4, a polarization separation unit (PBS) 5 that divides light into two polarization components is arranged. The light projecting unit 2 transmits the P-polarized light component, which is the first polarized light component in the light emitted from the light-emitting unit 3, through the polarized light separating element provided on the inclined surface 51 of the PBS 5 to the LCOS 4, and then reflects it by the LCOS 4. Thus, the S-polarized light component as the second polarized light component is used, and this S-polarized light component is reflected by the polarization separation element provided on the inclined surface 51 of the PBS 5 and guided to the lens 11.
In addition, the light projecting unit 2 includes an adjusting unit 6 that adjusts the positional relationship between the light emitting unit 3, the LCOS 4 and the PBS 5 by moving any one of the light emitting unit 3, the LCOS 4 and the PBS 5 relative to the remaining two. Yes.

Hereinafter, the light projecting unit 2 of the image display apparatus 1 of this example will be described in detail with reference to FIGS.
As shown in FIGS. 1 and 2, the light emitting unit 3 of this example is configured using light emitting diodes of three primary colors of red, blue, and green. In the light emitting unit 3 of this example, two green light emitting diodes are arranged diagonally, a red light emitting diode and a blue light emitting diode are arranged diagonally, and the light emitting diodes are arranged in a square shape. Do it.

The reflective liquid crystal display unit (element) (LCOS) 4 of this example has the property of reflecting the liquid crystal by rotating the polarization axis by 90 ° by the phase difference of the liquid crystal.
The polarization separation unit 5 of this example has a cube-shaped polarization beam formed in a cube shape (cuboid shape) by arranging and joining polarization separation elements (thin films) between 45 ° inclined surfaces 51 of two right-angle prisms. Splitter (PBS). Further, the PBS 5 transmits the P-polarized light component, which is the first polarized light component, by the polarized light separation element on the inclined surface 51, while reflecting the S-polarized light component, which is the second polarized light component, by the polarized light separating element on the inclined surface 51. have. In FIG. 2, the S-polarized component is indicated by an arrow S, and the P-polarized component is indicated by an arrow P.

  As shown in FIG. 2, the light projecting unit 2 of this example is used as a video engine of a liquid crystal projector as the image display device 1. The light projecting unit 2 is housed in a casing 12 of a liquid crystal projector, and is configured to project an image displayed by the LCOS 4 from a lens 11 provided in the casing 12 on a screen or the like.

As shown in FIGS. 1 and 2, the lens 11 is disposed to face the PBS 5 in a direction orthogonal to the direction in which the PBS 5, the light emitting unit 3, and the LCOS 4 face each other.
The adjusting means 6 of this example is configured so that PBS 5 and LCOS 4 are integrated by an assembly member or the like, and the light emitting unit 3 is moved with respect to the integrated PBS 5 and LCOS 4 so as to adjust the positional relationship between them. is there. The adjusting means 6 of this example is configured to slide the movable base 72 provided with the light emitting unit 3 with respect to the fixed base 71 in which the PBS 5 and the LCOS 4 are integrated using a worm gear mechanism. The worm gear mechanism includes a worm (screw gear) 61 and a worm wheel (helical gear) 62 that meshes with the worm (screw gear) 61. A large reduction ratio can be obtained by the worm gear mechanism, and the accuracy of movement adjustment of the movable base 72 can be improved.
In addition, after adjusting the arrangement relationship by the adjusting means 6, the movable base 72 can be fixed to the fixed base 71 with screws or the like.

In the light projecting unit 2 of the image display apparatus 1 of the present example, the adjusting unit 6 can move the light emitting unit 3 relative to the LCOS 4 and the PBS 5 to adjust the positional relationship between them. Thereby, when the light projecting unit 2 is assembled or when adjusting the light projecting unit 2 after the assembly, even when a positional or angular shift occurs in the arrangement relationship between the light emitting unit 3 and the LCOS 4 and the PBS 5. The position, the angle, and the like are corrected, and these can be finely adjusted to the optimum arrangement relationship for clearly displaying the video.
Therefore, according to the light projecting unit 2 of the image display apparatus 1 of the present example, the positional relationship between the light emitting unit 3, the LCOS 4 and the PBS 5 and the positional deviation, which are generated at the time of assembling, etc. Can be fine-tuned to various arrangement relationships.

In addition to the worm gear mechanism, the adjusting means 6 may be various mechanisms that can adjust the arrangement relationship. In addition to the mechanism that performs the slide movement, the adjusting means 6 may be a mechanism that performs the rotational movement as long as the position and angle of the arrangement relationship can be adjusted.
In addition to the cube-type PBS, the polarization separation unit 5 can be a polarization separation element having various structures that can be polarized. Moreover, the light emission part 3 can be used as various light emission sources, such as a lamp, besides LED. In addition, a light tunnel, a condenser lens, or the like can be disposed between the light emitting unit 3 and the polarization separating unit 5.

  In addition, the light projecting unit 2 may be configured by arranging the light emitting unit 3 and the reflective liquid crystal display unit (LCOS) 4 at 90 ° angles with respect to the polarization separating unit (PBS) 5. . Then, the light projecting unit 2 reflects the S-polarized component in the light emitted from the light emitting unit 3 by the polarization separation element provided on the inclined surface 51 of the PBS 5 and guides it to the LCOS 4, and then reflects the S-polarized component by the LCOS 4 to form the P-polarized component. The P-polarized component may be guided to the lens 11 through the polarization separation element provided on the inclined surface 51 of the PBS 5.

The perspective view which shows typically the light projection part of the image display apparatus in an Example. Explanatory drawing which shows typically the state which looked at the light projection part of the image display apparatus in the Example from the side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Image display apparatus 11 Lens 2 Light projection part 3 Light emission part 4 Reflective type liquid crystal display part (LCOS)
5 Polarization separator (PBS)
51 slope 6 adjusting means 71 fixed base 72 movable base PP polarization component SS polarization component

Claims (1)

A light emitting unit, a reflective liquid crystal display unit, and a polarization separating unit are arranged,
The first polarized component in the light emitted from the light emitting unit is transmitted or reflected by the polarized light separating unit, and then reflected by the reflective liquid crystal display unit to be a second polarized component, and the second polarized component is In the light projecting unit of the image display device configured to be reflected or transmitted by the polarization separating unit,
There is an adjusting means that adjusts the positional relationship between the light emitting unit, the reflective liquid crystal display unit, and the polarization separation unit by moving relative to the other two. The light projection part of the image display apparatus characterized by the above-mentioned.

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