JP4689948B2 - projector - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a projector, and more particularly to a projector having a tilt angle measuring and focusing device for calculating a tilt angle between an optical axis of a projection device of a projector to be used and a projection surface.
[0002]
[Prior art]
With the rapid development of liquid crystal technology and DLP (digital light processing) technology, the miniaturization and high performance of projectors have expanded the use of projectors for image projection, and large-scale replacements for display-type televisions at home. It is also attracting attention as a display device.
[0003]
However, unlike a display-type television, the projector has a screen or a wall, so that it is necessary to adjust the focus so that an image is formed on the projection surface every time the projector is installed. Since manual adjustment is complicated, automatic focus adjustment has also been proposed. Japanese Patent Application Laid-Open No. 11-1198185 has a focus adjustment mechanism for a projection lens, and a movable transmissive reflector is provided between the light source and the projection lens. In the focus adjustment mode, the movable transmissive reflector is disposed between the light source and the projection lens. An autofocus device for a liquid crystal projector is disclosed, in which reflected light from a screen is received by a light receiving element at a position equivalent to a light source, a focus position is detected and calculated by a received light output signal, and a focus adjustment mechanism is controlled. .
[0004]
In addition, unlike a display-type television, a projector has a problem in that an image is distorted due to a relative relationship between the optical axis of the projector and a projection surface because the image surface is a screen or a wall. Japanese Patent Laid-Open No. 9-281597 has a projector installation angle detection means and a distance detection means for detecting the distance between the projector and the projection target, and the angle of the liquid crystal display unit is calculated based on the angle calculated from both detection results. A method of adjusting is disclosed. Japanese Patent Application Laid-Open No. 2001-169221 discloses that a light point of a laser pointer capable of angle control is projected on a curved screen, while a point image for measurement is generated, projected from the projector onto the screen, and photographed with a camera. Coordinate conversion parameter memory by replacing the pixel coordinates on the frame memory of the point image with the coordinates on the input image of the light point when the points coincide with each other while moving the point image by measuring the position of the light spot and the point image Distortion correction methods set in the above are disclosed. In this case, it is necessary to control the angle of the laser pointer, and the structure becomes complicated.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-1198185 [Patent Document 2]
JP-A-9-281597 [Patent Document 3]
[Patent Document 1] Japanese Patent Application Laid-Open No. 2001-169 211
[Problems to be solved by the invention]
However, the autofocus device for a liquid crystal projector disclosed in Japanese Patent Application Laid-Open No. 11-1198185 has a problem that it is necessary to pull out the movable reflector every time the focus adjustment mode is selected because the brightness of the light source is reduced by the movable reflector. It was.
[0007]
Further, in the distortion correction method disclosed in Japanese Patent Laid-Open No. 9-281597, it is necessary to mechanically adjust the angle of the liquid crystal display unit. In the distortion correction method disclosed in Japanese Patent Laid-Open No. 2001-169221, a laser is used. There is a problem that the angle of the pointer needs to be controlled and the structure becomes complicated.
[0008]
On the other hand, when the vertical and horizontal inclinations of the screen with respect to the optical axis of the projector are known, a technique for projecting an image without distortion by converting the coordinates of the frame memory of the projector has been put into practical use. As a method for detecting the tilt of the projector with respect to the image, a horizontal or vertical test pattern projected from the projector is photographed with an image sensor placed away from the projection lens, and the tilt of the projector relative to the screen is determined from the tilt of the photographed test pattern. Although there is a method of detection, it is necessary to project the test pattern in advance and control the image in advance.
[0009]
In addition, until now, it has been necessary to perform the adjustment of the focus of the projection lens according to the distance between the projection apparatus and the projection surface separately from the adjustment of the distortion of the image.
[0010]
The object of the present invention is to display a test pattern with invisible light that can measure the vertical and horizontal tilt angles of the screen with respect to the optical axis of the projector during normal projection while suppressing the reduction of visible light brightness. It is another object of the present invention to provide a projector having an inclination angle measuring / focusing adjusting device capable of automatic focusing.
[0011]
[Means for Solving the Problems]
A projector having a focus adjustment device according to a first aspect of the projector of the present invention,
A projector having an automatic focal point adjusting means in a projection lens of a projector using a grid display device that reflects and projects light rays from an external light source, and the light beams from the light source are incident on the grid display device. A prism having an invisible light reflecting film that separates light into invisible light refracted from the visible light, an optical insulator with a slit that shapes the invisible light into an invisible light test pattern in the path of the separated invisible light, A total reflection mirror that refracts the invisible light test pattern toward the projection lens, a digital camera that captures the invisible light test pattern projected on the projection surface at a position aligned with the projection lens at a predetermined interval, and a digital camera The imaging state of the invisible light test pattern is obtained from the image and the focal position to the projection surface is obtained. An imaging state calculation unit that adjusts the focal point of the projection lens by calculating and calculating, the distance from the display surface of the lattice display device to the projection lens, the distance from the optical insulator to the total reflection mirror, and the total reflection mirror The distance from the projection lens to the projection lens is the same.
[0012]
A projector having a tilt angle measurement which is a second aspect of the projector of the present invention,
A projector having a tilt angle measuring device for calculating a tilt angle between a projection optical axis and a projection surface of a projection device of a projector using a grid display device that reflects and projects light rays from an external light source, the light source A prism having an invisible light reflecting film that separates the light from the visible light incident on the lattice display device and the invisible light refracted from the visible light, and the invisible light in the path of the separated invisible light. Optical insulator with slit that shapes invisible light test pattern in horizontal and vertical directions, total reflection mirror that refracts invisible light test pattern toward projection lens, and invisible light test pattern projected on projection surface And a digital camera that captures images at positions that are aligned at a predetermined interval, and the output of the video display unit according to the calculated tilt angle In order to correct the distortion of the image on the projection surface by controlling the image, it has an image analysis inclination angle calculation unit that calculates the inclination angle between the projection optical axis of the projection device of the projector and the projection surface, and the image analysis The tilt angle calculation unit obtains the tilt of the invisible light test pattern on the projection surface captured by the digital camera as the difference in the number of pixels at the intersection of the invisible light test pattern and both ends of the image capture screen, and determines the test pattern from the difference in the number of pixels. And the reference angle indicating the vertical direction and the horizontal direction of the projection apparatus are analyzed, and the inclination angle between the projection optical axis of the projection apparatus of the projector and the projection surface is calculated from the inclination angle. The sum of the distance from the display surface to the projection lens, the distance from the optical insulator to the total reflection mirror, and the distance from the total reflection mirror to the projection lens is the same. That.
[0013]
A projector having an inclination angle measurement / focus adjustment device according to a third aspect of the projector of the present invention,
An automatic focus adjustment means for a projection lens of a projector using a grid display device that reflects and projects light rays from an external light source, and an inclination for calculating an inclination angle between the projection optical axis of the projector and the projection surface A projector having an angle measuring device, wherein a light beam from a light source is separated from a prism having an invisible light reflection film that separates a visible light beam incident on a lattice display device and an invisible light beam refracted from the visible light beam. An optical insulator with a slit that shapes the invisible light into a horizontal and vertical invisible light test pattern, a total reflection mirror that refracts the invisible light test pattern toward the projection lens, and a projection surface A digital camera that captures the invisible light test pattern projected on the screen at a predetermined distance from the projection lens. An imaging state calculation unit that obtains the imaging state of the invisible light test pattern from the image of the digital camera, detects and calculates the focal position to the projection surface, and adjusts the focus of the projection lens, according to the calculated inclination angle In order to correct the distortion of the image on the projection surface by controlling the output image of the image display unit, an image analysis inclination angle calculation unit for calculating the inclination angle between the projection optical axis of the projector and the projection surface is provided. Then, the image analysis inclination angle calculation unit obtains the inclination of the invisible light test pattern on the projection surface captured by the digital camera as the difference in the number of pixels at the intersection of the invisible light test pattern and both ends of the imaging screen. The inclination angle between the test pattern and the reference line indicating the vertical direction and horizontal direction of the projection device is analyzed from the difference between the projection angle and the projection optical axis of the projection device of the projector from the inclination angle. Calculate the angle of inclination with the projection surface, and the sum of the distance from the display surface of the grid display device to the projection lens, the distance from the optical insulator to the total reflection mirror, and the distance from the total reflection mirror to the projection lens are the same. It is configured to be.
[0014]
The control of the output video of the video display unit according to the tilt angle between the projection optical axis and the projection surface of the projection device of the projector is based on the correction value of the input video of the video display unit calculated in advance corresponding to the tilt angle. It may be executed by creating a control parameter and controlling the projector image processing LSI, the grid display device may be a DMD display unit, and the invisible light may be infrared.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a DLP (digital light processor) type projector using a DMD (digital micromirror device) which is a grid-like display device, and separates invisible light separated by an invisible light separation film separately from an optical path of an image by an input signal. The invisible light that has an optical path passes through the slit and displays a test pattern on the screen. Further, the optical path length from the projection lens to the slit and the projection lens to the video display device represented by DMD are displayed. The optical path length is equal, the focus of the projection lens is adjusted from the image formation state of the test pattern on the screen, and the image control unit adjusts the distortion by the inclination of the test pattern imaged by the digital camera. .
[0016]
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block configuration diagram of a projector having an inclination angle measurement / focus adjustment device according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of a projection device of the projector, and FIG. It is typical explanatory drawing of the projector which has an inclination angle measurement and a focus adjustment apparatus, (a) is a typical side view which shows a projection state, (b) is a typical front view of a projector, (c) is an imaging of a digital camera It is a schematic diagram of a screen.
[0017]
Here, a DLP (digital light processing) type projector will be described as an example. However, the present invention can be similarly applied to a projector using a grid display device that reflects and projects light rays from a light source . Although invisible light is infrared, it is not limited to infrared.
[0018]
The projector 10 includes a projection lens 21, a DMD display unit 22, a light source 23, an infrared ray separation unit 24, a color wheel 25, and a focus adjustment unit 26, and an image control unit 30 that controls an image on the DMD display unit 22. And a tilt angle measurement / focus adjustment device 40 and a CPU 60 for controlling the overall operation.
[0019]
As shown in FIG. 2, the infrared separation unit 24 includes a prism 241 having an infrared reflection film 242 provided on one surface, an optical insulator 243 with a slit, and a total reflection mirror 244, and is directed from the light source 23 toward the DMD display unit 22. The projected light beam 101 is separated into a visible light beam 102 and an infrared light beam 103 by a prism 241 having an infrared reflection film 242 provided on one surface in front of the color wheel 25, and the visible light beam 102 is directly projected on the DMD display unit 22, The separated and refracted infrared light 103 passes through the slit-shaped optical insulator 243 to become an infrared test pattern 83 in the shape of a slit. The direction of the infrared test pattern 83 is refracted in the direction of the projection lens 21 by the total reflection mirror 244, and DMD Projection lens 21 together with visible light beam 102 reflected by display unit 22 Via projects the projection surface 70.
[0020]
The tilt angle measuring / focusing adjustment device 40 analyzes the pixels of the infrared test pattern 83 of the image captured by the digital camera 50 having the infrared transmission filter 53, the imaging lens 51, and the imaging device 52, and the imaging surface 52. An image analysis inclination angle calculation unit 41 that calculates vertical and horizontal inclinations of the projection device 20 and an image formation state calculation unit 42 that detects the image formation state by analyzing pixels of the infrared test pattern 83 are provided.
[0021]
As shown in FIG. 3A, the projector 10 is usually arranged on the cradle 90 so as to be inclined in the vertical direction so that an image is projected onto a projection surface 70 such as a screen or a wall. In this case, when projection is performed in a state where the projection optical axis 27 of the projection device 20 of the projector 10 and the projection surface 70 are orthogonal to each other, the screen of the DMD display unit 22 is enlarged and projected on the projection surface as it is. When the plane orthogonal to the projection optical axis 27 and the projection plane 70 are inclined, the distance from the projection lens 21 changes depending on the position as compared with the case where the plane is orthogonal. For example, the screen is enlarged because the screen is enlarged at a distant position. There arises a problem that a trapezoidal distortion occurs on the screen. In order to solve this problem, for example, a device as described in the above-mentioned patent document has been made. In this case, if the inclination angle between the vertical plane and the projection plane 70 with respect to the projection optical axis 27 of the projection device 20 can be accurately grasped, the projection plane is obtained by moving the arrangement of the image of the DMD display section 22 to the pixels by the image control section 30. The image projected on 70 can be corrected to the correct state, and the mobility can be obtained numerically from the tilt angle by a known technique.
[0022]
The present invention aims at accurately grasping the tilt angle between the projection optical axis 27 and the projection surface 70 of the projection apparatus 20 and further adjusting the focus of the projection lens 21, and tilt angle measurement and focus adjustment described below. The purpose is achieved by the device 40.
[0023]
In the projection device 20, the light beam 101 from the light source 23 passes through the prism 241 having the infrared reflection film 242 of the infrared separator 24, so that only the visible light 102 passes through the color wheel 25 and is reflected by the mirror of the DMD display unit 22. Then, the output image passes through the projection lens 21 and is projected onto the projection surface 70. On the other hand, the infrared ray 103 included in the light beam 101 projected from the light source 23 toward the DMD display unit 22 is separated from the visible light beam 102 by the infrared reflection film 242 provided on the prism 241, and the optical axis is changed at the same time. The infrared ray 103 that has passed through the optical insulator 243 with slits becomes an infrared test pattern 83 in the shape of a slit. Further, the direction of the infrared test pattern 83 is refracted in the direction of the projection lens 21 by the total reflection mirror 244, and the DMD display unit It is projected onto the projection surface 70 via the projection lens 21 together with the visible light beam 102 reflected by the lens 22. In this case, the distance from the display surface of the DMD display unit 22 to the center of the projection lens 21, the distance from the slit of the optical insulator 243 with slit to the center of the total reflection mirror 244, and the center of the total reflection mirror 244 to the center of the projection lens 21. The sum of the distance to the distance to is the same. That is, since the distance of visible light from the DMD display unit 22 to the center of the projection lens 21 and the distance of the infrared ray 103 of the infrared test pattern 83 from the slit to the center of the projection lens 21 are the same, the visible light 102 and the infrared light 103 are under the same conditions. An image is formed on the projection surface 70. Therefore, when the imaging state of the infrared test pattern 83 is acquired and the focus of the projection lens 21 is adjusted so that this imaging state is good, the focus of the image by the visible light is also adjusted and a good image is obtained.
[0024]
Specifically, the adjustment of the focus of the projection lens 21 will be described. Since the imaging lens 51 is provided with the infrared transmission filter 53, the imaging screen 80 of the imaging device 52 has an infrared test pattern as shown in FIG. Only 83a and 83b are displayed. The imaging state calculation unit 42 of the tilt angle measurement / focus adjustment device 40 acquires the pixel distribution state of the infrared test patterns 83a and 83b on the imaging screen 80, and the pixel distribution state of the infrared test patterns 83a and 83b is less than a predetermined width. Thus, the focus adjustment unit 26 is operated via the image control unit 30.
[0025]
In this embodiment, the purpose is to measure the tilt accuracy as well as the focus adjustment, so the slit shape is a horizontal and vertical cross line, but a cross hatch composed of a plurality of cross lines may be used, and only the focus adjustment is performed. If desired, only vertical lines or horizontal lines may be used. If only the focus adjustment is intended, the image analysis tilt angle calculation unit 41 may be excluded, and the tilt angle measurement / focus adjustment device 40 may be a focus adjustment device. Except for the state calculation unit 42, the tilt angle measurement / focus adjustment device 40 may be a tilt angle measurement device.
[0026]
In order to accurately grasp the tilt angle between the vertical plane and the projection plane 70 with respect to the projection optical axis 27 of the projection device 20, the projection lens 21 and the imaging lens 51 are illustrated so that the tilt of the infrared test pattern is displayed large. As shown in FIG. 3 (b), it is desirable that they are arranged so as to be separated in the vertical direction and the horizontal direction. Since the imaging lens 51 is provided with the infrared transmission filter 53, only the infrared test pattern is displayed on the imaging screen of the imaging device 52 even during image projection.
[0027]
FIG. 3C shows an imaging screen 80 when the vertical infrared test pattern 83a and the horizontal infrared test pattern 83b projected on the projection surface 70 are imaged by the imaging device 52 of the digital camera 50, and the projection surface 70 is projected at the top. Since the image is tilted away from the lens 21, the upper side of the vertical infrared test pattern 83a is seen in the image of the image sensor 52 taken at a position away from the projection lens 21 in the horizontal direction as shown in FIG. It is displayed at the position on the right side of the lower side. Similarly, although not shown in the drawing, the projection surface 70 is inclined in the direction away from the projection lens 21 on the left side. Therefore, in the image of the imaging element 52 imaged at a position away from the projection lens 21 in the vertical direction, horizontal infrared rays are used. The test pattern 83b is displayed at a position where the left side is higher than the right side.
[0028]
The image analysis inclination angle calculation unit 41 analyzes the vertical infrared test pattern 83a and the horizontal infrared test pattern 83b on the imaging screen 80 from the respective pixels, and calculates the projection optical axis 27 and the projection plane 70 of the projection device 20 by a predetermined calculation formula. The vertical and horizontal tilt angles are calculated and output to the image control unit 30. The image control unit 30 moves the arrangement of the image of the DMD display unit 22 to the pixels by a predetermined calculation formula based on the tilt angle. Thus, the image projected on the projection surface 70 is corrected to a correct state.
[0029]
FIG. 4 is a schematic flowchart showing a standard process for correcting the output video of the DMD display unit 22 from the difference pixel number. The image analysis inclination angle calculation unit 41 acquires the difference pixel number information about the difference pixel number 86 in the vertical direction and the difference pixel number 87 in the horizontal direction on the same line from the imaging screen 80 of the imaging element 52 (step S1). Is used to generate an inclination angle between the optical axis of the projection device 20 and the projection surface 70 (step S2), and the image control unit 30 generates an LSI control parameter in response to the generated inclination angle (step S3). By controlling the image processing LSI (step S4), the input video 28 is modified to become an output video 29 on the DMD display unit 22. When the output image 29 is projected onto the projection surface 70, the output image 29 is similar to the input image 28.
[0030]
【The invention's effect】
As described above, the present invention can easily adjust the focus of the projection lens and the tilt angle in the vertical direction and the horizontal direction between the projection optical axis and the projection surface of the projection apparatus. In addition, there is an effect that the image projected on the projection surface can be accurately corrected to a correct state by moving the arrangement of the image on the liquid crystal display unit to the pixels.
[0031]
This is an infrared ray that is separated from the visible light together with the image by the visible light from the projection lens of the projector arranged in the horizontal direction and the vertical direction away from the imaging lens of the digital camera of the tilt angle measuring / focusing device. The infrared test pattern consisting of the above is projected onto the projection surface in the vertical and horizontal directions, and only the infrared test pattern separated by the infrared transmission film is imaged with a digital camera. The vertical and horizontal tilt angles of the projection optical axis and the projection surface of the projection apparatus can be calculated by adjusting the vertical and horizontal tilts of the test pattern and generating the tilt angles using the number of differential pixels at both ends. Therefore, it is possible to control so as to eliminate the distortion of the screen of the liquid crystal display unit from the tilt angle.
[0032]
Further, there is an effect that the adjustment of the focus of the projection lens and the calculation of the tilt angle can be executed without affecting the image even during the image projection.
[0033]
This separates the light from the light source into visible light and infrared light, and the image is projected directly from the DMD display section through the projection lens with visible light, and the separated infrared light passes through the slit through the projection lens as an infrared test pattern. Therefore, the infrared test pattern is always projected during the projection of the image, and there is no optical obstacle from the DMD display unit to the projection lens, which may affect the image. Because there is no.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a projector having an inclination angle measurement / focus adjustment apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a projector of the projector.
FIG. 3 is a schematic explanatory diagram of a projector having the tilt angle measurement / focus adjustment apparatus of the present invention.
(A) is a typical side view which shows a projection state.
FIG. 2B is a schematic front view of the projector.
(C) is a schematic diagram of the imaging screen of a digital camera.
FIG. 4 is a schematic flowchart showing a standard process for correcting an output image of a DMD display unit based on the number of difference pixels.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Projector 20 Projector 21 Projection lens 22 DMD display part 23 Light source 24 Infrared separation part 25 Color wheel 26 Focus adjustment part 27 Projection optical axis 28 Input image 29 Output image 30 Image control part 40 Inclination angle measurement and focus adjustment apparatus 41 Image analysis Inclination angle calculation unit 42 Imaging state calculation unit 50 Digital camera 51 Imaging lens 52 Imaging element 53 Infrared transmission filter 60 CPU
70 Projection Surface 80 Imaging Screen 83 Infrared Test Pattern 83a Vertical Infrared Test Pattern 83b Horizontal Infrared Test Pattern 86 Vertical Difference Pixel Number 87 Horizontal Difference Pixel Number 90 Placement 101 Light Beam 102 Visible Light Light 103 Infrared Light 241 Prism 242 Infrared Reflecting Film 243 Slit Optics Insulator 244 Total reflection mirror S1-S4 Step

Claims (5)

A projection lens, a projection apparatus having a grid-like display and a light source, and an image control means for controlling the image of the grid-like display unit, have a control unit for controlling the entire operation, the grid-like display unit A projector that projects an output image onto a projection surface through the projection lens ;
Invisible light separating means for separating invisible light from light from the light source;
A test pattern shaping unit different from the lattice-shaped display unit for shaping the invisible light separated by the invisible light separation unit into a test pattern;
Imaging means that images the invisible light test pattern shaped by the test pattern shaping means and projected onto the projection surface via the projection lens ;
The optical path length from the projection lens to the test pattern shaping means is equal to the optical path length from the projection lens to the lattice display unit,
A projector that automatically adjusts a projected image by analyzing an invisible light test pattern imaged by the imaging means. Focus adjusting means for adjusting the focus of the projection lens;
An imaging state calculation unit that analyzes the invisible light test pattern imaged by the imaging unit and operates the focus adjustment unit so that an imaging state of the invisible light test pattern on the projection surface is good; Have
The projector according to claim 1, wherein the projection image is automatically adjusted by adjusting a focus of the projection lens according to an imaging state of the invisible light test pattern on the projection surface. Analyzing the invisible light test pattern of the image captured by the imaging means, and having an inclination angle calculation means for calculating an inclination angle between the vertical plane and the projection plane with respect to the projection optical axis of the projection lens,
The projected image is automatically adjusted by moving the arrangement of the grid-like display unit to pixels according to the tilt angle so as to correct distortion of the image projected on the projection surface. The projector according to claim 1 or claim 2. The imaging means has an imaging lens,
The projector according to any one of claims 1 to 3 , wherein the projection lens and the imaging lens are arranged so as to be separated from each other at a predetermined interval. The projector according to any one of claims 1 to 4 , wherein the invisible light is an infrared ray.

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