US-12625418-B2 - Projector

US12625418B2US 12625418 B2US12625418 B2US 12625418B2US-12625418-B2

Abstract

A projector includes a single light modulator that has a pixel region containing a plurality of pixels, and a pixel shifting device configured to switch the optical path of image light output from the light modulator between a reference optical path and a shifted optical path. A plurality of sub-pixels that are segmented by a black matrix and output light having different colors form each of the pixels in the pixel region of the light modulator. The pixel shifting device positions the image light traveling along the reference optical path at a reference display position on the projection receiving surface, and positions the image light traveling along the shifted optical path at a shifted display position on the projection receiving surface to superimpose the image light output from the sub-pixels at the shifted display position on a region corresponding to the black matrix at the reference display position.

Inventors

Shinichi Wakabayashi
Masato Kadotani

Assignees

SEIKO EPSON CORPORATION

Dates

Publication Date: 20260512
Application Date: 20231129
Priority Date: 20221129

Claims (16)

1 . A projector comprising: a light source; a single light modulator that has a pixel region containing a plurality of pixels and modulates light output from the light source to generate image light; a pixel shifting device configured to switch an optical path of the image light output from the light modulator between a reference optical path and a shifted optical path; and a projection system that projects the image light incident from the pixel shifting device onto a projection receiving surface, wherein a plurality of sub-pixels that are segmented by a black matrix and output light having different colors form each of the pixels in the pixel region of the light modulator, the pixel shifting device positions the image light traveling along the reference optical path at a reference display position on the projection receiving surface and positions the image light traveling along the shifted optical path at a shifted display position on the projection receiving surface to superimpose the image light output from the sub-pixels at the shifted display position on a region corresponding to the black matrix at the reference display position.
2 . The projector according to claim 1 , wherein the pixels in the pixel region are each formed of four of the sub-pixels, the four sub-pixels disposed on diagonal lines that intersect with each other and form two pairs.
3 . The projector according to claim 2 , wherein one of the four sub-pixels, which constitute a first pixel that is one of the plurality of pixels, is assumed to be a reference sub-pixel, and the pixel shifting device shifts the optical path of the image light output from the reference sub-pixel in one direction relative to the reference optical path to form the shifted optical path to superimpose the image light output from the reference sub-pixel at the shifted display position on a region corresponding to a first portion of the black matrix at the reference display position, the first portion surrounded by corners of the four sub-pixels, which constitute the first pixel.
4 . The projector according to claim 3 , wherein an optical axis of the image light output from the reference sub-pixel at the shifted display position is located at the center of the region corresponding to the first portion.
5 . The projector according to claim 2 , wherein one of the four sub-pixels, which constitute a first pixel that is one of the plurality of pixels, is assumed to be a reference sub-pixel, the pixel shifting device is configured to switch the optical path of the image light output from the reference sub-pixel to the shifted optical path formed of a first shifted optical path as a result of shifting the optical path of the image light in a first direction relative to the reference optical path and a second shifted optical path as a result of shifting the optical path of the image light in a second direction different from the first direction relative to the first shifted optical path, and positions the image light traveling along the first shifted optical path at a first shifted display position on the projection receiving surface, and positions the image light traveling along the second shifted optical path at a second shifted display position on the projection receiving surface, and the first shifted optical path causes the image light output from the reference sub-pixel at the first shifted display position to be superimposed on a region corresponding to a second portion of the black matrix at the reference display position, the second portion segmenting two of the sub-pixels adjacent to each other out of the four sub-pixels that constitute the first pixel, and the second shifted optical path causes the image light output from the reference sub-pixel at the second shifted display position to be shifted from the first shifted optical path and superimposed on the region corresponding to a third portion of the black matrix at the reference display position, the third portion surrounded by corners of the four sub-pixels that constitute the first pixel.
6 . The projector according to claim 5 , wherein an optical axis of the image light output from the reference sub-pixel at the first shifted display position is located at a center of the region corresponding to the second portion, and the optical axis of the image light output from the reference sub-pixel at the second shifted display position is located at a center of the region corresponding to the third portion.
7 . The projector according to claim 5 , wherein the pixel shifting device is configured to further switch the optical path of the image light output from the reference sub-pixel to a third shifted optical path, as the shifted optical path, as a result of shifting the optical path of the image light in a third direction different from the first and second directions relative to the reference optical path, and positions the image light traveling along the third shifted optical path at a third shifted display position on the projection receiving surface, and the third shifted optical path causes the image light output from the reference sub-pixel at the third shifted display position to be shifted from the second shifted optical path and superimposed on a region corresponding to a fourth portion of the black matrix different from the second portion at the reference display position, the fourth portion segmenting two of the sub-pixels adjacent to each other out of the four sub-pixels that constitute the first pixel.
8 . The projector according to claim 7 , wherein the optical axis of the image light output from the reference sub-pixel at the third shifted display position is located at a center of the region corresponding to the fourth portion of the black matrix.
9 . The projector according to claim 1 , wherein the plurality of pixels in the pixel region of the light modulator are arranged in a row direction and a column direction perpendicular to each other, the plurality of pixels include a first pixel and a second pixel adjacent to each other in the column direction, and the first pixel and the second pixel each include at least three of the sub-pixels sequentially arranged in the row direction.
10 . The projector according to claim 9 , wherein one of the plurality of sub-pixels in the first pixel is assumed to be a reference sub-pixel, and the pixel shifting device shifts the optical path of the image light output from the reference sub-pixel in one direction relative to the reference optical path to form the shifted optical path to superimpose the image light output from the reference sub-pixel at the shifted display position on a region corresponding to a fifth portion of the black matrix at the reference display position, the fifth portion surrounded by corners of two sub-pixels adjacent to each other in the first pixel and corners of two sub-pixels in the second pixel that are adjacent to the two sub-pixels adjacent to each other in the first pixel.
11 . The projector according to claim 10 , wherein the optical axis of the image light output from the reference sub-pixel at the shifted display position is located at a center of the region corresponding to the fifth portion.
12 . The projector according to claim 9 , wherein one of the plurality of sub-pixels in the first pixel is assumed to be a reference sub-pixel, the pixel shifting device is configured to switch the optical path of the image light output from the reference sub-pixel to the shifted optical path formed of a first shifted optical path as a result of shifting the optical path of the image light in a first direction relative to the reference optical path and a second shifted optical path as a result of shifting the optical path of the image light in a second direction different from the first direction relative to the first shifted optical path, and positions the image light traveling along the first shifted optical path at a first shifted display position on the projection receiving surface, and positions the image light traveling along the second shifted optical path at a second shifted display position on the projection receiving surface, the first shifted optical path causes the image light output from the reference sub-pixel at the first shifted display position to be superimposed on a region corresponding to a sixth portion of the black matrix at the reference display position, the sixth portion segmenting two sub-pixels adjacent to each other in the first pixel, and the second shifted optical path causes the image light output from the reference sub-pixel at the second shifted display position to be shifted from the first shifted optical path and superimposed on a region corresponding to a seventh portion of the black matrix at the reference display position, the seventh portion surrounded by corners of two sub-pixels adjacent to each other in the first pixel and corners of two sub-pixels in the second pixel that are adjacent to the two sub-pixels adjacent to each other in the first pixel.
13 . The projector according to claim 12 , wherein the optical axis of the image light output from the reference sub-pixel and traveling along the first shifted optical path is located at a center of the region corresponding to the sixth portion, and the optical axis of the image light output from the reference sub-pixel and traveling along the second shifted optical path is located at a center of the region corresponding to the seventh portion.
14 . The projector according to claim 12 , wherein an amount of shift in the first direction differs from an amount of shift in the second direction.
15 . The projector according to claim 12 , wherein the pixel shifting device is configured to further switch the optical path of the image light output from the reference sub-pixel to a third shifted optical path, as the shifted optical path, as a result of shifting the optical path of the image light in a third direction different from the first and second directions relative to the reference optical path, and positions the image light traveling along the third shifted optical path at a third shifted display position on the projection receiving surface, and the third shifted optical path causes the image light output from the reference sub-pixel at the third shifted display position to be shifted from the second shifted optical path and superimposed on a region corresponding to an eighth portion of the black matrix at the reference display position, the eighth portion segmenting the reference sub-pixel of the first pixel and the sub-pixel of the second pixel that is adjacent to the reference sub-pixel of the first pixel.
16 . The projector according to claim 15 , wherein the optical axis of the image light output from the reference sub-pixel and traveling along the third shifted optical path is located at a center of the region corresponding to the eighth portion.

Description

The present application is based on, and claims priority from JP Application Serial Number 2022-190074, filed Nov. 29, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety. BACKGROUND 1. Technical Field The present disclosure relates to a projector. 2. Related Art JP-A-7-319066 discloses a projector using a single liquid crystal panel as a light modulation apparatus. In the projector, the light output from a light source enters the liquid crystal panel, image light modulated by the liquid crystal panel is caused to exit out of a projection lens, and the image light having exited out of the projection lens is reflected off a mirror to redirect the projected image light. JP-A-7-319066 is an example of the related art. Such a single-panel projector using a single liquid crystal panel has advantages of compactness, lightweight, excellent portability, and low cost. On the other hand, the single-panel projector has a problem of poorer resolution than that of a three-panel projector using three liquid crystal panels. It has therefore been desired to provide a new technology that can increase the resolution while maintaining the advantages of the single-panel projector. SUMMARY According to an aspect of the present disclosure, there is provided a projector including a light source, a single light modulator that has a pixel region containing a plurality of pixels and modulates light output from the light source to generate image light, a pixel shifting device configured to switch an optical path of the image light output from the light modulator between a reference optical path and a shifted optical path, and a projection system that projects the image light incident from the pixel shifting device onto a projection receiving surface. A plurality of sub-pixels that are segmented by a black matrix and output light having different colors form each of the pixels in the pixel region of the light modulator. The pixel shifting device positions the image light traveling along the reference optical path at a reference display position on the projection receiving surface, and positions the image light traveling along the shifted optical path at a shifted display position on the projection receiving surface to superimpose the image light output from the sub-pixels at the shifted display position on a region corresponding to the black matrix at the reference display position. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a schematic configuration of a projector according to a first embodiment. FIG. 2 is a plan view of a pixel shifting device. FIG. 3 is a plan view showing key portions of the structure of the pixels of a liquid crystal panel. FIG. 4 describes the principle of an increase in the resolution of an image. FIG. 5 is a plan view of the pixel shifting device in a second embodiment. FIG. 6 describes the principle of an increase in the resolution of an image. FIG. 7 is a plan view showing the structure of the pixels of the liquid crystal panel in a first variation. FIG. 8 describes the principle of an increase in the resolution of an image in the first variation. FIG. 9 shows key portions of a displayed image achieved by the pixel shifting in a second variation. FIG. 10 shows key portions of a displayed image achieved by the pixel shifting in a third variation. FIG. 11A shows pixel shift operation in a fourth variation. FIG. 11B shows the pixel shift operation in the fourth variation. FIG. 11C shows the pixel shift operation in the fourth variation. DESCRIPTION OF EMBODIMENTS Embodiments of the present disclosure will be described below in detail with reference to the drawings. In the drawings used in the description below, a characteristic portion is enlarged for convenience in some cases for clarity of the characteristic thereof, and the dimension ratio and other factors of each component are therefore not always equal to actual values. First Embodiment FIG. 1 shows a schematic configuration of a projector 100 according to the present embodiment. The projector 100 according to the present embodiment is a projection-type image display apparatus that displays a color image on a screen SCR, which is a projection receiving surface, as shown in FIG. 1. The projector 100 includes a light source unit 1, an image generator 2, a projection system 3, a pixel shifting device 4, a fan 5, an inner enclosure 6, and an exterior enclosure 7. In the following description, an XYZ coordinate system shown in FIG. 1 is used in some cases to describe the arrangement of the members described above. In FIG. 1, the axis X is an axis extending along a first optical axis AX1, which is a first reference axis along which some of the optical parts in the projector 100 are arranged. The axis Y is perpendicular to the axis X, is an axis extending along a second optical axis AX2, which is a second reference axis along which some of the other optical parts in the projector 100 are arranged, and is an axis extending