JP2008164752A - Rear projection projector - Google Patents

Abstract

To provide a rear projection type projector that can always adjust brightness without being influenced by a video signal and can perform color adjustment with simple work without being influenced by an external environment.
Light emitted from a light source 12 is selectively passed through a color filter as red, green, and blue light, and converted into parallel light by a light tunnel 14. The light valve 20 modulates and controls the light from the light tunnel 14, and the light projection control unit 22 controls the light valve 20 based on the imaging signal. The light amount detection unit 23 detects the amount of light transmitted outside the light path in the optical path between the light tunnel 14 and the light valve 20, and the light amount adjustment unit 24 projects the light on the screen based on the light amount detected by the light amount detection unit 23. Adjust the amount of light emitted.
[Selection] Figure 1

Description

  The present invention relates to a rear projection projector that projects video and text information on a transmissive screen.

  As a kind of rear projection type projector device, light emitted from a light source is passed through a color filter, and the light passing through the light tunnel as parallel light is irradiated to a light valve, for example, a DMD (Digital Mirror Device) panel, which is reflected light. Some project image light onto a screen via a projection lens (zoom projection lens). The DMD is a digital mirror device in which hundreds of thousands of mirror elements each having a controllable tilt are mounted on a semiconductor memory cell, and an image is formed by controlling the tilt of each mirror element to control the reflection state.

  And, in a video display device that forms a large screen by combining a plurality of such rear projection projectors, brightness adjustment and color adjustment are required. This is because if the brightness and color of each rear projection type projector device is different, the brightness and color of the large screen image will vary partially, resulting in a poor-looking image. The reason is that the brightness of the light source of the rear projection type projector device changes with time, and gradually decreases from the time of product shipment. In this case, due to individual differences in the light source and optical components of the rear projection type rear projector device, the brightness and color of the video differ for each rear projection type rear projector device and do not match.

  Therefore, there is a projector that uses a DMD that always projects an image with constant brightness (for example, see Patent Document 1). In Patent Document 1, the amount of light when the DMD is in the OFF state (when tilted by 12 degrees) is detected by a sensor, the voltage level is compared with the reference voltage level, and control is performed so that they match.

On the other hand, in a multi-display device that forms a single screen by combining a plurality of projection displays, when the multi-display device is installed, the white balance and gamma characteristics, luminance unevenness, color unevenness, etc. of the display are automatically adjusted. (For example, refer to Patent Document 2). In this patent document 2, images of a multi-display device are taken with a camera, and gamma characteristics and white balance are adjusted automatically and in a short time.
JP 2003-280090 A JP-A-6-217336

  However, in Patent Document 1, since accurate light amount detection can be performed only when there is no video signal (black), the accuracy of light amount adjustment is reduced. Also, the arrangement of the light quantity sensor seems to be difficult. On the other hand, in the case of Patent Document 2, it is necessary to install a sensor (camera) outside the display device, and it is also necessary to consider the lighting environment, so the work becomes complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a rear-projection type projector that can always adjust brightness without being influenced by a video signal and can perform color adjustment with a simple operation without being affected by an external environment. is there.

  A rear projection type projector apparatus according to a first aspect of the present invention is directed to a light source; a color filter that selectively allows light emitted from the light source to pass; and light from the light source that has passed through the color filter is input and projected onto a screen. A light tunnel for converting the light into parallel light; a light valve for modulating and controlling light from the light tunnel; a light projecting control unit for controlling the light valve based on an imaging signal; and the light tunnel and the light valve. A light amount detection unit that detects the amount of light transmitted outside the light path in the intermediate light path; and a light amount adjustment unit that adjusts the light amount of light projected on the screen based on the light amount detected by the light amount detection unit. It is characterized by that.

  In the present invention and the following inventions, definitions and technical meanings of terms are as follows unless otherwise specified.

  The light source is, for example, a discharge or a light emitting diode. A color filter selectively passes light emitted from a light source as red, green, and blue light. For example, red, green, and blue color filters are attached to a disk-shaped color wheel, and the disk rotates. The light emitted from the light source is filtered in the order of red, green, and blue and output to the light tunnel.

  The light tunnel is formed in, for example, a square tube, and receives light from a light source, reflects it on a mirror surface on the inner surface of the square tube, and outputs the input light as square parallel light. The light emitted from the light tunnel is input to the light valve via a relay lens, a mirror, and a prism as necessary.

  The light valve is formed of, for example, a DMD (Digital Mirror Device) panel, and tilts the light from the light tunnel onto the screen (tilt 12 degrees) and tilts the light from the light tunnel onto the screen. It is formed of a large number of mirror elements that can take two states (−12 degrees tilt).

  The light projection control unit controls the light valve based on the imaging signal and creates an image on the screen. The light amount detection unit always detects the amount of light transmitted to the outside of the light path in the light path between the light tunnel and the light valve. In this case, it is preferable to detect the amount of light after the color filter or light tunnel. The reason is that light that has passed through a light conversion unit such as a color filter or a light tunnel is light that contributes to a substantial image, and therefore light detected in the region is close to light that is actually projected. It is. Therefore, when the amount of light after the color filter or light tunnel is detected, it is easy to accurately detect and adjust the amount of light.

  Therefore, for example, light outside the optical path transmitted to the back side of the mirror disposed in the optical path between the light tunnel and the light valve is always detected. Alternatively, the light outside the optical path transmitted to the back side of the prism disposed in the optical path between the light tunnel and the light valve is always detected. The reason why the amount of light is measured outside the optical path is that if the amount of light is measured along the optical path, a shadow of the light amount detector is formed and reflected on the screen. Further, since the amount of light transmitted outside the optical path is proportional to the amount of light irradiated on the screen, the amount of light irradiated on the screen can be obtained by detecting the amount of light transmitted outside the optical path. .

  The light amount adjustment unit outputs a light amount adjustment signal for adjusting the light amount of light projected on the screen based on the light amount detected by the light amount detection unit to the light projection control unit. The light projection control unit receives a light amount adjustment signal from the light amount control unit, and outputs a signal to the light valve in consideration of the light amount adjustment signal when creating an image on the screen. The light modulated by the light valve becomes an image. As a result, the light projection control unit modulates the light from the light tunnel via the light valve when creating an image on the screen, and obtains an image in consideration of the light amount adjustment signal.

  A rear projection type projector apparatus according to a second aspect of the present invention is the rear projection type projector apparatus according to the first aspect of the present invention, wherein the rear projection type projector apparatus is disposed until the light emitted from the projection lens that projects onto the screen is projected onto the screen. A movable light color detection unit that is disposed substantially at the center of the optical path at the time of detection, and is disposed outside the light path when the light color is not detected; based on the light color detected by the light color detection unit A light color adjusting unit that adjusts the light color of the light projected on the screen.

  The projection lens is a zoom projection lens that irradiates a screen with light created by a light valve and visualized. The light color detection unit is a detector that detects the color of light and is movable. The light color detection unit is disposed until the light emitted from the projection lens that projects onto the screen is projected onto the screen. This is to measure the color of the light irradiated on the screen. The movable light color detection unit is disposed almost at the center of the optical path of the light emitted from the projection lens that projects the light only when detecting the color of the light irradiated on the screen. When not detecting, it is placed outside the optical path.

  The light color adjustment unit outputs a light color adjustment signal for adjusting the light color of the light projected on the screen based on the light color detected by the light color detection unit to the light projection control unit. The light projection control unit receives a light color adjustment signal from the light color control unit, and outputs a signal that takes into account the light color adjustment signal to the light valve when creating an image on the screen. The light modulated by the light valve becomes an image. As a result, the light projection control unit modulates the light from the light tunnel via the light valve when creating the image on the screen, and obtains an image in consideration of the light color adjustment signal.

  According to a third aspect of the present invention, there is provided a rear projection type projector apparatus according to the second aspect, wherein the light color adjusting unit projects light based on a reference video signal onto at least the light color detecting unit. To do.

  The light color adjustment unit projects light based on the reference video signal instead of light based on the video signal to the light color detection unit. Thereby, the reference color of the light irradiated on the screen can be easily understood.

  According to the first aspect of the present invention, the amount of light radiated to the screen is always detected by the light detection unit in the light path between the light tunnel and the light valve, and is detected by the light amount adjustment unit. Since the amount of light is constantly adjusted, the amount of light irradiated on the screen can be adjusted constantly without being affected by the video signal.

  According to the invention of claim 2, when the light color is detected in the optical path until the light emitted from the projection lens that projects onto the screen is projected onto the screen as the light color irradiated on the screen. The light color detector is placed at the approximate center of the optical path, and the light color adjustment unit adjusts the light color of the light projected on the screen based on the light color detected by the light color detector, so it is affected by the external environment. The light color can be adjusted with a simple operation.

  According to the third aspect of the present invention, since the light based on the reference video signal is projected onto the movable light color detection unit at the time of light color detection, the reference color of the light irradiated on the screen can be easily understood.

  FIG. 1 is an explanatory diagram of a rear projection type projector apparatus according to an embodiment of the present invention. FIG. 1 (a) is a configuration diagram, and FIG. 1 (b) is a cross-sectional view taken along line AA 'in FIG. FIG. A light source 12 is housed in the projector apparatus main body 11, and light from the light source 12 passes through a color filter attached to the color wheel 13 and is output to the light tunnel 14.

  The color wheel 13 is formed in a disk shape, and for example, red, green, and blue color filters are attached thereto. A motor 16 is attached to the central shaft of the color wheel 13 and is rotated by the motor 16. By the rotation of the color wheel 13, the light emitted from the light source 12 is filtered in the order of red, green, and blue and output to the light tunnel 14.

  The light filtered into red, green, or blue by the color filter of the color wheel 13 is converted into parallel light by the light tunnel 14. As shown in FIG. 1B, the light tunnel 14 is formed in, for example, a rectangular tube, and receives light from the light source 12 and reflects it by a mirror surface on the inner surface of the rectangular tube to convert the input light into a rectangular parallel light. And output. The light emitted from the light tunnel 14 passes through the relay lens 17a, is reflected by the mirrors 18a and 18b, and is input to the prism 19 through the relay lens 17b.

  The light incident on the prism 19 is reflected and input to the light valve 20, the reflected light is adjusted by the light valve 20, and is irradiated onto an external screen via the projection lens 21.

  The light valve 20 is formed of, for example, a DMD panel. The DMD panel is composed of a large number of mirror elements, and each mirror element can take two states of a 12 degree inclination and a -12 degree inclination. On the other hand, the tilted state in which the reflected light is projected onto the screen is tilted. On the other hand, in the case of the tilt at −12 degrees, the tilted state in which the light from the light tunnel 14 is not projected onto the screen. In the DMD panel, the light projection control unit 22 controls the inclination of a large number of mirror elements. The light projection control unit 22 controls the tilt of the mirror element of the light valve 20 based on the imaging signal, and creates an image on the screen.

  Next, a light amount detector 23 is provided on the back side of the mirror 18b. The light quantity detector 23 always detects the quantity of light transmitted outside the optical path in the optical path between the light tunnel 14 and the light valve 20, and in FIG. 1A, the light quantity detector 23 is a mirror. Since it is installed on the back side of 18b, the light quantity detection unit 23 always detects the light outside the optical path transmitted through the mirror 18b. The reason why the light amount detection unit 23 is provided on the back side of the mirror 18b is that the back surface of the mirror 18b (18a) forms a part of the projector apparatus body 11, and therefore the light amount detection unit 23 can be easily attached. .

  The part other than the back surface of the mirror 18b (18a) may be the back side of the prism 19 arranged in the optical path between the light tunnel 14 and the light valve 20. In this case, light outside the optical path transmitted through the prism 19 is always detected on the back side of the prism 19. Since the prism 19 is housed in the projector apparatus main body 11, the projector apparatus main body 11 is opened and attached when the light quantity detector 23 is attached.

  Here, the amount of light is measured outside the optical path between the light tunnel 14 and the light valve 20 because when the amount of light is directly measured in the optical path, a shadow of the light amount detector 23 is formed and the shadow is reflected on the screen. Because. Further, since the amount of light transmitted outside the optical path is proportional to the amount of light irradiated on the screen, the amount of light irradiated on the screen can be obtained by detecting the amount of light transmitted outside the optical path. .

  The light amount adjustment unit 24 outputs a light amount adjustment signal for adjusting the light amount of light projected on the screen based on the light amount detected by the light amount detection unit 23 to the light projection control unit 22. The light projection control unit 22 receives the light amount adjustment signal from the light amount control unit 24 and outputs a signal that takes the light amount adjustment signal into the light valve 20 when creating an image on the screen. Then, for example, the light modulated by the light valve 20 by the combination of the 12 ° tilted state and the −12 ° tilted state of the mirror element becomes an image and is output to the projection lens 21.

  For example, in a video display device that configures a large screen by combining a plurality of rear projection type projector devices, the amount of light is adjusted so that the brightness of each rear projection type projector device is equal.

  FIG. 2 is an explanatory view of a rear projection type projector apparatus having a light color adjustment function according to the embodiment of the present invention, and FIG. 2A is a plan view of a screen irradiation image at the time of light color adjustment. 2 (b) is a side view of the rear projection type projector apparatus at the time of light color adjustment, and FIG. 2 (c) is a top view of the rear projection type projector apparatus at the time of light color adjustment.

  As shown in FIG. 2B, the light color detection unit 25 is attached to the movable table 26, and the movable light color detection unit 25 is configured such that light emitted from the projection lens 21 that projects the screen 27 is emitted from the screen. 27 until it is projected onto the screen. When detecting the light color, the movable base 26 is raised so as to block the irradiation surface of the screen 27, and as shown in FIG. 2 (a), the light color detection unit 25 is arranged at substantially the center position of the optical path. . Therefore, the color adjustment is performed when the video by the rear projection type projector device is stopped, that is, when the video is stopped or during inspection adjustment.

  On the other hand, when the light color is not detected, the movable base 26 is tilted so that the light color detector 25 is located outside the optical path. Thereby, in the normal video state in which the rear projection type projector device projects the video on the screen 27, the light color detection unit 25 does not become a shadow of the video.

  As described above, the detection of the light color is performed when the image is stopped or inspected / adjusted. The change in the light amount (attenuation) of the light applied to the screen 27 and the change in the color are more drastic in the light amount attenuation and the variation is large. Because. That is, as shown in FIG. 1, it is preferable that the light amount is always detected by the light amount detection unit 23 and is always controlled by the light amount control unit 24 as shown in FIG. It can be said that adjustment is sufficient. Therefore, the color adjustment is performed when the video by the rear projection type projector device is stopped, that is, when the video is stopped or at the time of inspection and adjustment.

  As described above, when detecting the light color, the movable base 26 is raised so as to be blocked by the irradiation surface of the screen 27, and as shown in FIG. Try to be in the center position. In this state, light from the video signal is emitted from the light projection control unit 22 toward the screen 27. Light from the video signal is detected by the light color detection unit 25 and input to the light color adjustment unit 28. The light color adjustment unit 28 adjusts the light color of the light projected on the screen 27 based on the light color detected by the light color detection unit 25.

  At that time, the light color adjusting unit 28 irradiates the light color detecting unit 25 with light based on the reference video signal. FIG. 2A shows a case where the light Lr based on the reference video signal is irradiated to the region at the substantially central position of the optical path where the light color detection unit 25 is located, and the light Lv based on the video signal is irradiated to both sides of the region. Yes. In this way, by irradiating the light color detection unit 25 with light based on the reference video signal, the reference color of the light irradiated on the screen can be easily understood.

  According to the embodiment of the present invention, while the light emitted from the light source 12 is incident on the light valve (DMD panel) through the light tunnel 13, the light amount detection unit 23 is prevented from being shaded by the video signal. Since the amount of light applied to the screen is always corrected by the light amount adjusting unit 24, the amount of light irradiated onto the screen can be adjusted constantly.

  In addition, a movable light color detection unit is arranged until the light emitted from the projection lens 21 is projected onto the screen 27, and the light color adjustment unit 28 corrects the light color at the time of arbitrary inspection and adjustment. The light color can be adjusted by simple work without being affected by the external environment. At that time, by irradiating the light color detection unit 25 with light based on the reference video signal, the reference color of the light irradiated on the screen can be easily understood.

Explanatory drawing of an example of the rear projection type projector apparatus concerning embodiment of this invention. Explanatory drawing of the other example of the rear projection type projector apparatus concerning embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Projector apparatus main body, 12 ... Light source, 13 ... Color wheel, 14 ... Light tunnel, 16 ... Motor, 17 ... Relay lens, 18 ... Mirror, 19 ... Prism, 20 ... Light valve, 21 ... Projection lens, 22 ... Throw Light control unit, 23 ... light amount detection unit, 24 ... light amount adjustment unit, 25 ... light color detection unit, 26 ... movable stand, 27 ... screen, 28 ... light color adjustment unit

Claims (3)

With a light source;
A color filter for selectively passing light emitted from the light source;
A light tunnel that inputs light from a light source that has passed through the color filter and converts the light into parallel light that is projected onto a screen;
A light valve for modulating and controlling light from the light tunnel;
A light projection control unit for controlling the light valve based on an imaging signal;
A light amount detector for detecting the amount of light transmitted outside the light path in the light path between the light tunnel and the light valve;
A light amount adjusting unit that adjusts the amount of light projected on the screen based on the light amount detected by the light amount detecting unit;
A rear projection type projector apparatus comprising: When the light emitted from the projection lens that projects on the screen is projected until it is projected onto the screen, and is positioned at the approximate center position of the optical path when detecting the light color, and when the light color is not detected Is a movable light color detector disposed outside the optical path;
The rear projection projector according to claim 1, further comprising: a light color adjustment unit that adjusts a light color of light projected on the screen based on the light color detected by the light color detection unit.   The rear projection projector according to claim 2, wherein the light color adjustment unit projects light based on a reference video signal on at least the light color detection unit.

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