JP4454288B2 - projector - Google Patents

Description

  The present invention relates to a projector that projects image data on a screen such as a personal computer, a camera, or a television, and in particular, projects a test pattern on the screen, and reads the image of the test pattern to correct distortion of the projected image, autofocus, etc. The present invention relates to a projector that performs processing.

  In recent years, liquid crystal projectors and DLP (Digital Light Processing) projectors are compact and lightweight devices that are excellent in portability, so that their use in various scenes is rapidly increasing.

  Unlike a stationary CRT projector, such a portable projector is supposed to be displayed in an environment in which the positional relationship between the screen and the projector is changed. In this case, it is necessary to adjust the image according to the positional relationship between the screen and the projector. Specifically, it is necessary to adjust the screen size and focal length according to the distance between the screen and the projector. In addition, it is necessary to correct the screen shape according to the inclination and curvature of the screen.

Conventionally, when performing auto focus and image distortion correction as described above, the test pattern is projected onto the screen with red, green, and blue light, and the test pattern (projected image) on the screen is imaged. The pattern was analyzed based on a known test pattern, and the focal length and image distortion were corrected (see, for example, Patent Documents 1 and 2).
JP 2000-28901 A (see paragraph numbers [0002] to [0003]) Japanese Patent No. 2538435

  However, since the test pattern image is originally an unnecessary image and is an image of R, G, and B visible light, when projected onto the screen, the original image is obstructed and is troublesome.

  For this reason, when the projected test pattern is used for autofocus and image distortion correction processing, the display of the video by the input signal is stopped and only the test pattern is displayed on the screen.

  Therefore, with a conventional projector, it is impossible to always perform autofocus and image distortion correction using a test pattern while displaying an original video.

  An object of the present invention is to provide a projector that can always perform autofocus and image distortion correction processing using a test pattern while displaying an image based on an input signal in view of the above-described problems of the prior art. .

In order to achieve the above object, a projector according to the present invention includes a light source that emits white light including invisible light,
A color wheel configured to transmit and rotate light from the light source;
An image forming means for forming an image by light passing through the color wheel;
A projection lens for enlarging and projecting an image formed by the image forming means on a screen;
A condenser lens for condensing the image projected by the projection lens for on the screen,
An invisible light transmitting filter that allows only invisible light to pass through the image collected by the condenser lens;
Detecting means for detecting an image of invisible light that has passed through the invisible light transmission filter;
An image forming means control section for controlling the image forming means to control the image forming means based on a video signal and to form a test pattern image at a predetermined cycle;
A detection means controller for controlling the detection means so as to acquire the test pattern image in synchronization with the formation of the test pattern image by the image forming means,
The color wheel includes a red transmission part that transmits red light and a blue transmission part that transmits blue light, and at least one of the red transmission part and the blue transmission part also transmits invisible light.

  In the configuration as described above, white light from the light source is incident through the rotating color wheel, and the image forming unit forms a color image by the light that has passed through the color wheel. This color image is projected onto the screen by the projection lens. When the red transmission part of the color wheel is a part that also transmits invisible light, the image forming means controls the image forming means control part for a moment while the light from the light source passes through the red transmission part of the color wheel. An image of the test pattern is formed. During this “instant”, an image of a test pattern that is invisible light on the screen and is not related to the target image is enlarged and projected by the projection lens.

  The test pattern image of the invisible light on the screen is condensed by the condensing lens in the projector main body, and only the invisible light is transmitted through the invisible light transmitting filter and enters the detecting means. The detection unit control unit operates the detection unit in synchronization with the test pattern image formation by the image forming unit control unit. Processing such as autofocus and image distortion correction is performed using the test pattern image detected by the detection means.

  In the projector, an invisible light removal filter that does not transmit invisible light is disposed in an optical path from the light source to the color wheel, and the invisible light removal filter transmits a part of light in a wavelength region of the invisible light. Those having the following characteristics are preferred.

  The image forming means can apply DMD.

  The projector can perform autofocus processing or image distortion correction processing based on a test pattern image of invisible light detected by the detection means.

  The invisible light is infrared light or ultraviolet light.

  A CCD, CMOS sensor or PSD can be used as the detection means.

  According to the present invention, an image of a test pattern is projected on a screen while light from a light source passes through a red transmissive portion or a blue transmissive portion that transmits invisible light of a color wheel, and the image of the test pattern is projected. Can be input to the detection means, and processing such as autofocus and image distortion correction can be performed while a color image is displayed on the screen.

  Furthermore, in the present invention, either the red transmission part or the blue transmission part of the color wheel is made an area that also transmits invisible light. With this configuration, in a conventional DLP projector using three color wheels of R, G, and B, three images (red (R) including infrared) can be obtained without changing the number of colors constituting the color wheel. 3 image, green (G) image, and blue (B) image) can be combined into a single color image, so a conventional DLP projector using three color wheels of R, G, and B Compared with, it is not necessary to reduce the image brightness.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic diagram showing a schematic configuration of a DLP projector according to a first embodiment of the present invention, and FIG. 2 is a configuration diagram of a color wheel shown in FIG.

  Referring to FIG. 1, a projector 11 according to this embodiment includes a light source 1 such as a high-pressure mercury lamp that emits white light, a color wheel 2 on which light from the light source 1 is incident, and each color light passing through the color wheel 2 has a period. Formed by a DMD 3 which is an image forming means for forming a dot matrix image, a DMD control unit 31 for controlling the DMD 3, a video input unit 9 for inputting a video signal to the DMD control unit 31, and a DMD 3 A projection lens 4 for enlarging and projecting the projected image on the screen 5, a condenser lens 6 for condensing the image projected on the screen 5, and infrared light that passes only infrared light out of the light passing through the condenser lens 6. A light transmission filter 7, an image sensor 8 that captures an image of infrared light that has passed through the infrared light transmission filter 7, and an image sensor that controls the image sensor 81 in synchronization with the test pattern image formation by the DMD 3. And a device control unit 81.

  A CCD (Charge Coupled Device), a CMOS sensor (Complementary Metal Oxide Semiconductor), or the like can be used for the imaging device 8.

  Although not shown, a converging lens is disposed in the optical path between the light source 1 and the color wheel 2 and between the color wheel 2 and the DMD 3.

  The screen 5 is installed at a position away from the projector 11.

  The projection lens 4 and the condenser lens 6 are arranged at a position facing the screen 5.

  The color wheel 2 is a disk-shaped color filter that is driven to rotate.

  The DMD 3 is provided with micron-sized micromirrors tilted to ± 10 degrees according to on / off of input signals based on image data, which are spread over hundreds of thousands to millions. Each micromirror switches (on / off) the reflected light toward the screen 5 based on the image data, thereby forming a projection image. By making white light from the light source enter the DMD 3 through the rotating color wheel 2, the projected image becomes a color. At this time, one micromirror is in charge of one pixel of the projected image, and takes charge of each color of R, G, and B in a time division manner. For example, in order to display a color image of 60 frames per second, the color wheel 2 is rotated at a cycle that is three times that, and R, G, and B are displayed in a time-sharing manner. That is, R, G, and B images are projected onto the screen in 1/180 second units. In this case, the actual color composition is processed by the human brain. Note that image data serving as an input signal to the DMD 3 is output from a personal computer, digital video, or the like.

  As shown in FIG. 2, red (R) of the three primary colors of red (R), green (G), and blue (B) is transmitted to the outer periphery of the color wheel 2 across which the light from the light source 1 crosses. In addition, the infrared and red transmission part 21 that transmits infrared light, the green transmission part 22 that transmits green (G), and the blue transmission part 23 that transmits blue (B) are divided into the same area. Yes.

  Next, the operation of the projector according to the present embodiment will be described. FIG. 4 is a flowchart for explaining the operation of the characteristic part of the projector according to the present embodiment.

  The DMD control unit 31 controls the micromirrors of the DMD 3 based on the video signal input from the video input unit 9 and forms an image with the reflected light of the micromirrors of the DMD 3.

  The DMD 3 displays an image of the test pattern by the DMD control unit 31 for a moment while the light from the light source 1 passes through the infrared and red transmission unit 21 of the color wheel 2 within the above image formation period. (Step S1 in FIG. 4). Then, an image of a test pattern unrelated to the target image is enlarged and projected on the screen 5 by the projection lens 4 with red and infrared light. As shown in FIG. 3, the “instantaneous” period in which the DMD 3 displays the test pattern image is about 10 μS according to the response speed when controlling the micromirrors of the DMD 3. Therefore, the DMD 3 can perform the micromirror operation 1500 times (= 1/60 [s] / 10 [μS]) in the display period (1/60 seconds) of one frame of video. Since the color wheel 2 is divided into three parts and the DMD 3 displays the test pattern image by one micromirror operation when the light passes through the infrared and red transmission parts 21 of the color wheel 2, the test pattern image is Only a period of 1/500 or less of the red display period (1/180 seconds) is displayed on the screen 5. For this reason, the visible light image on the screen 5 is hardly influenced by the image of the test pattern.

  Next, the test pattern image of red and infrared light on the screen 5 is condensed by the condenser lens 6 in the main body of the projector 11 and only infrared light is transmitted by the infrared light transmission filter 7 and imaged. Element 8 is entered.

  The DMD control unit 31 causes the DMD 3 to form a test pattern image and outputs a signal for operating the image sensor control unit 81 while the test pattern image is being formed. For this reason, the image sensor 8 can capture an image only while the DMD 3 forms an image of a test pattern (step S2 in FIG. 4). When a CCD or CMOS sensor is used for the image sensor 8, the test pattern image formed by the DMD 3 is an image of a pattern such as a rectangle, a lattice, or a combination of vertical and horizontal lines.

  In the present embodiment, the image sensor 8 is used as a test pattern detection unit. However, the present invention is not limited to this, and a PSD (Position Sensitive Device) can be used. The PSD is a device that returns the position as a current value when there is a single light spot on the element. Therefore, one point is used as a test pattern when the PSD is used.

  As described above, the test pattern is detected by a detection unit such as a CCD, a CMOS sensor, or a PSD, and processing such as autofocus and image distortion correction is performed using the detected test pattern.

  When performing autofocus, for example, the distance to the screen 5 is measured based on a test pattern imaged by the image sensor 8, and the focus of the projection lens 4 is adjusted based on the distance measurement data (by the applicant). (See Japanese Patent Application No. 2003-303826 for which it was filed).

  When image distortion correction is performed, for example, a test pattern composed of a plurality of points is used, and the inclination angle between the straight line connecting the points imaged by the image sensor 8 and the reference line is analyzed from the imaging screen of the image sensor 8. Then, the tilt angle between the optical axis of the projection lens 4 and the screen 5 is calculated from the tilt angle, and the image distortion on the screen 5 is corrected by controlling the output video according to the calculated tilt angle (by the applicant). (See Japanese Patent Application No. 2003-143501 filed).

  According to the present embodiment, a test pattern image is displayed on the screen 5 for a moment while the light from the light source 1 is passing through the infrared and red transmission portions 21 of the color wheel 2, and this test pattern image is displayed. Can be input to the image sensor 8, and processing such as autofocus and image distortion correction can be performed while a color image is displayed on the screen 5.

(Second Embodiment)
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 5 is a schematic diagram showing a schematic configuration of a DLP projector according to the second embodiment of the present invention, and FIG. 6 is a graph showing the relationship between light transmittance and wavelength of the infrared light removal filter shown in FIG. is there. In these drawings, the same reference numerals are used for the same components as those in the second embodiment.

  In the projector of the present embodiment, an infrared light removal filter 10 is disposed in the optical path from the light source 1 to the color wheel 2 to remove heat rays as shown in FIG. The infrared light removal filter 10 is a filter that does not transmit infrared light. However, since an image of the infrared light test pattern is captured by the image sensor 8, one of the infrared wavelength regions as shown in FIG. Part of light (light in the vicinity of a wavelength of about 900 nm) is transmitted.

  In the present embodiment, unlike the first embodiment, since a color image from which heat rays have been removed is displayed on the screen, even if the image on the screen is a still image for a long time, screen burn hardly occurs.

  As described above, the DLP projector has been described as an example of the projector according to the present invention. However, the present invention can be applied to a projector using a dot matrix display (lattice display) such as a liquid crystal panel. For example, in the configuration shown in FIGS. 1 and 5, by replacing the DMD 3 with a reflective liquid crystal panel, it is possible to perform processes such as autofocus and image distortion correction using a test pattern in the same manner as described above. .

  Moreover, although the structural example which uses an infrared test pattern was shown, it is sufficient to use invisible light that does not hinder the visual recognition of the image on the screen, it can be applied even with ultraviolet light.

  In the case of the DLP projector according to the first embodiment (FIG. 1), the infrared and red transmission portions 21 are made red transmission portions and the blue transmission portions 23 are made ultraviolet in the region where the outer peripheral portion of the color wheel 2 is divided into three. In place of the blue transmission part, the infrared light transmission filter 7 may be replaced with an ultraviolet light transmission filter. In the case of the DLP projector (FIG. 4) according to the second embodiment, in addition to such a change, the infrared light removal filter 10 has an ultraviolet characteristic that transmits part of light in the ultraviolet wavelength region. The configuration is replaced with a light removal filter.

It is a figure which shows schematic structure of the DLP projector by the 1st Embodiment of this invention. It is a block diagram of the color wheel shown in FIG. 2A and 2B are diagrams illustrating display periods of R, G, and B image components that constitute one frame of an image projected by the projector illustrated in FIG. 1, in which FIG. The test pattern display period during the red display period at the time of display, (c) shows the photographing timing of the image sensor. 3 is a flowchart for explaining an operation of a characteristic part of the projector shown in FIG. 1. It is a figure which shows schematic structure of the DLP projector by the 2nd Embodiment of this invention. It is a graph which shows the light transmittance and wavelength relationship of the infrared light removal filter shown in FIG.

Explanation of symbols

1 Light source 2 Color wheel 3 DMD
4 Projection lens 5 Screen 6 Condensing lens 7 Infrared light transmission filter 8 Image sensor 9 Video input unit 10 Infrared light removal filter 11 Projector 21 Infrared and red transmission unit 22 Green transmission unit 23 Blue transmission unit 31 DMD control unit 81 Image sensor control unit

Claims (7)

A light source that emits white light including invisible light;
A color wheel configured to transmit and rotate light from the light source;
An image forming means for forming an image by light passing through the color wheel;
A projection lens for enlarging and projecting an image formed by the image forming means on a screen;
A condenser lens for condensing the image projected by the projection lens for on the screen,
An invisible light transmitting filter that allows only invisible light to pass through the image collected by the condenser lens;
Detecting means for detecting an image of invisible light that has passed through the invisible light transmission filter;
An image forming means control section for controlling the image forming means to control the image forming means based on a video signal and to form a test pattern image at a predetermined cycle;
A detection means controller for controlling the detection means so as to acquire the test pattern image in synchronization with the formation of the test pattern image by the image forming means,
The color wheel includes a red transmission part that transmits red light and a blue transmission part that transmits blue light, and at least one of the red transmission part and the blue transmission part also transmits invisible light. An invisible light removal filter that does not transmit invisible light is disposed in an optical path from the light source to the color wheel, and the invisible light removal filter has a characteristic of transmitting a part of light in the wavelength region of the invisible light. The projector according to claim 1 . It said image forming means projector according to claim 1 or 2 which is DMD. Implementing the autofocus processing based on the test pattern image of the invisible light detected by said detecting means, the projector according to any one of claims 1 to 3. Implementing an image distortion correction process on the basis of the test pattern image of the detected non-visible light by the detecting means, the projector according to any one of claims 1 to 3. The invisible light is an infrared or ultraviolet light, the projector according to any one of claims 1 to 5. The projector according to any one of claims 1 to 6 for use CCD, a CMOS sensor or PSD to said detecting means.

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