JP2006023415A - Projection type image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type image display apparatus capable of accurately focusing by preventing the erroneous detection of a sensor with a simple constitution. <P>SOLUTION: The projection type image display apparatus for modulating light emitted from a light source 1 by liquid crystal light valves 31, 32 and 33, and then, projecting an image through a projection lens 16, is provided with the sensor 29 for imaging the projected image, a control part 25 for calculating contrast data and/or angular data based on the imaging data of the sensor 29, and also, focusing and/or compensating keystone distortion, a blocking member 60 for preventing dust from sticking to the sensor 29 by covering the sensor 29, and a driving means for shifting the cover 60 up to an open state. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection display apparatus such as a liquid crystal projector.

As this type of projection display apparatus, a light emitting element and a light receiving element covered with a light emitting window and a light receiving window are provided in the projection display apparatus body, respectively, and projected from the light emitting element toward the screen. It is known that the distance between the projection display device and the screen is estimated based on the intensity of the reflected infrared light received by the light receiving element, and the focus is adjusted by adjusting the position of the projection lens based on the estimated distance. (See, for example, Patent Document 1).
JP-A-6-27431

  The light emitting element and the light receiving element are respectively covered with the light emitting window and the light receiving window, and dust can be prevented from adhering to the light emitting element and the light receiving element. Accordingly, it is possible to prevent erroneous detection of the distance between the projection display apparatus and the screen due to a change in the intensity of light received by the light receiving element due to dust adhering to the light emitting element or the light receiving element.

  However, even if there is a slight distortion on the surface of the light emitting window or the light receiving window, the light receiving intensity received by the light receiving element may change due to the diffuse reflection of light. It is necessary to employ a precise light emitting window and light receiving window, and there is a problem that costs increase.

  Even when a high-precision light-emitting window or light-receiving window without distortion is used, if the light-emitting window or light-receiving window is damaged or pride adheres to the light-emitting window or light-receiving window, the light-receiving intensity received by the light-receiving element changes. Therefore, there has been a problem of erroneously detecting the distance between the projection display apparatus and the screen.

  Accordingly, the present invention has been made to solve such a problem, and provides a projection display apparatus capable of preventing erroneous detection of a sensor and performing accurate focus adjustment with a simple configuration. Is an issue.

  Means for solving the above-described problems include a sensor that captures a projected image in a projection display apparatus that modulates light emitted from a light source with a liquid crystal light valve and projects an image with a projection lens; A control unit that calculates contrast data and / or angle data based on imaging data and performs focus adjustment and / or trapezoidal distortion correction; and a blocking member that covers the sensor and prevents dust from adhering to the sensor And a driving means for moving the closing member to the open state.

  In the means for solving the above-mentioned problems, the closing member may be configured to be opened when the sensor images a projected image.

  The closing member may be configured to be closed when the sensor does not capture the projected image.

  According to the configuration of the first aspect of the present invention, since the sensor is covered with the closing member, it is possible to prevent dust from adhering to the sensor, and to prevent erroneous detection of the sensor due to dust adhering to the sensor. As a result, it is possible to perform accurate focus adjustment and / or trapezoidal distortion correction.

  According to the configuration of the second aspect of the present invention, when the sensor captures an image, the closing member covering the sensor is opened. Therefore, when the closing member is distorted or scratched, dust adheres to the closing member. Even in this case, erroneous detection of the sensor can be prevented, and effects such as focus adjustment and / or trapezoidal distortion correction can be achieved more accurately.

  According to the configuration of claim 3 of the present invention, since the closing member is closed except when the sensor captures an image, it is possible to prevent the dust from adhering to the sensor as much as possible.

  A projection display apparatus according to an embodiment of the present invention will be described below in detail with reference to FIGS.

  FIGS. 1 and 2 are views showing a three-plate liquid crystal projector 30 as a projection display apparatus according to this embodiment. The light emitting unit in the light source 1 is composed of an ultra-high pressure mercury lamp, a metal halide lamp, a xenon lamp, or the like.

  The integrator lens 4 is composed of a pair of lens groups (fly eye lenses) 4a and 4b, and each lens portion guides light emitted from the light source 1 to the entire surfaces of liquid crystal light valves 31, 32, and 33 described later. Thus, the partial luminance unevenness existing in the light source 1 is averaged, and the light amount difference between the center of the screen and the peripheral portion is reduced. The light passing through the integrator lens 4 is guided to the first dichroic mirror 7 after passing through the polarization conversion device 5 and the condenser lens 6.

  The first dichroic mirror 7 transmits light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band that has passed through the first dichroic mirror 7 is reflected by the reflection mirror 8 to change the optical path. The red light reflected by the reflection mirror 8 is light-modulated by passing through a lens 9 and a transmissive liquid crystal light valve 31 for red light. The light in the cyan wavelength band reflected by the first dichroic mirror 7 is guided to the second dichroic mirror 10.

  The second dichroic mirror 10 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 10 is guided to the transmissive liquid crystal light valve 32 for green light through the lens 11 and is modulated by being transmitted therethrough. The light in the blue wavelength band that has passed through the second dichroic mirror 10 is guided to the blue-light transmissive liquid crystal light valve 33 through the total reflection mirror 12, total reflection mirror 13, and lens 14, and is transmitted therethrough. It is optically modulated.

  Each of the liquid crystal light valves 31, 32, 33 includes a panel portion 31b, in which liquid crystal is sealed between an incident-side polarizing plate 31a, 32a, 33a and a pair of glass substrates (with pixel electrodes and alignment films formed). 32b and 33b and output side polarizing plates 31c, 32c and 33c.

  The modulated light (each color video light) modulated by passing through the liquid crystal light valves 31, 32, 33 is synthesized by the cross dichroic prism 15 to become color video light. The color image light is enlarged and projected by the projection lens 16 and displayed on the screen 40 (see FIG. 6).

  The projection lens 16 includes a focus motor (lens driving motor) 22 for focus adjustment. When a feed direction drive signal is input to the focus motor 22 from a microcomputer 25 (described later), the projection lens 16 moves in the feed direction, and a pull direction drive signal is input to the focus motor 22. Driven in the pull-in direction.

FIG. 3 is a block diagram showing an outline of the signal processing system of the liquid crystal projector 30. The video signal processing circuit 23 inputs a video signal and performs processing such as resolution conversion and image enlargement / reduction, and also executes image processing for trapezoidal distortion correction based on a command from the microcomputer 25. Each panel driver 24R, 24G, 24B inputs (drives) a video signal (video data) to each liquid crystal light valve 31, 32, 33.

  The operation unit 27 is provided with keys for various operations. In this embodiment, an adjustment instruction key 27a for instructing focus adjustment and trapezoidal distortion correction is provided.

  An OSD (On Screen Display) circuit 28 generates video data based on character information and graphic information instructed to be output from the microcomputer 25, and writes this video data in the image memory 21. The OSD circuit 29 can project an image created on the device side other than the input image.

  The sensor 29 includes a first sensor unit 29A and a second sensor unit 29B. As shown in FIG. 4, each sensor unit 29A, 29B includes a pair of lens units 29a and a CCD line sensor 29b provided corresponding to each lens unit 29a. The pair of lens portions 29a are adapted to form images on the CCD line sensor 29b.

  As shown in FIG. 1, the first sensor unit 29A is arranged such that a pair of lens units 29a are arranged in the vertical direction, and the second sensor unit 29B is arranged so that the pair of lens units 29a are arranged in the horizontal direction. Further, as shown in FIG. 5, the sensor 29 is covered with a cover 60 as a closing member that can be freely opened and closed, and is rotated by a driving means (not shown) with a pair of shafts as rotation centers.

  The microcomputer 25 samples the imaging signal of the sensor 29 to generate imaging data, and calculates contrast data and angle data. The contrast data is a signal indicating the degree of the high frequency component on the image pickup signal output from the CCD line sensor 29b. The higher the high frequency component is obtained on the image pickup signal, the more the focus state is indicated. The angle data includes first angle data θ1 (see FIG. 6A) indicating the degree of longitudinal trapezoidal distortion obtained by the first sensor unit 29A, and lateral trapezoidal distortion obtained by the second sensor unit 29B. There is second angle data θ2 (see FIG. 6B) indicating the degree of.

  The angle data can be obtained by a calculation process based on a distance measurement result from the sensor 29 to the adjustment projection image (screen 40). The distance measurement is performed by so-called triangulation, and can be obtained from the relative shift (phase difference) of the picked-up images on the CCD line sensors 29b of the sensor units 29A and 29B, the lens focal length, and the inter-lens distance. it can. The distance measurement can be performed for each of a plurality of areas in the imaging range of the adjustment projection image. That is, it is possible to divide the field angle range of the CCD line sensor 29b into a plurality of areas and calculate a distance measurement result for each distance measurement area. For example, distance measurement is performed for each of the uppermost area and the lowermost area (the leftmost area and the rightmost area) of the adjustment projection image. The difference in distance measurement between the uppermost area and the lowermost area (leftmost area and rightmost area) is a large value corresponding to the non-verticality between the projection optical axis and the screen. The angle data (θ1, θ2) can be calculated by obtaining the arc tangent from the difference between the distance between the areas (the leftmost area and the rightmost area) and the distance measurement value.

  The microcomputer 25 performs overall control in the liquid crystal projector 30. In particular, as control according to the present invention, adjustment control of the setting at the time of projection shown below is performed.

  After the power is turned on, the user waits for the light source to enter a sufficient light emission state, and then presses the adjustment instruction key 27a of the operation unit 27. When the microcomputer 25 detects the pressing of the adjustment instruction key 27a, it drives the driving means to open the cover 60 and draws the first adjustment projection video by the OSD circuit 28 (image data to the image memory 21). Execute (write). As shown in FIG. 7A, the first adjustment projection image is a stripe image in which white horizontal line regions and black horizontal line regions are alternately formed. Data forming such an image is directly used as the image memory. It is not written to 21.

  Specifically, the microcomputer 25 (OSD circuit 28) writes video data for one vertical line in the image memory 21. Then, the microcomputer 25 instructs the video signal processing circuit 23 to expand in the horizontal direction. If the number of horizontal pixels on one screen is 1024, the enlargement ratio is 1024 times. The video signal processing circuit 23 performs processing for multiplying the video data for one vertical line by 1024 in the horizontal direction, and supplies the video signals obtained by this processing to the panel drivers 24R, 24G, and 24B. For example, only one panel driver 24G may supply the video signal to project a green stripe image.

  Then, the microcomputer 25 gives a feeding direction drive signal to the focus motor 22 and samples the image pickup signal of the sensor 29 to generate contrast data. When starting the sampling, the microcomputer 25 starts a timer, generates contrast data at a constant time interval, and stores it in a memory (not shown). The microcomputer 25 determines the best contrast data, and acquires time information (focusing lens position information) when the contrast data is obtained. The microcomputer 25 gives a pull-in direction drive signal to the focus motor 22 for a time obtained by subtracting the time information from the total time when the feed-out direction drive signal is given to the focus motor 22. Thereby, focus adjustment is realized.

  Further, the microcomputer 25 performs trapezoidal distortion correction based on the image data of the sensor 29. The trapezoidal distortion includes a vertical trapezoidal distortion and a horizontal trapezoidal distortion. First, in the first adjustment projection image shown in FIG. 6A, processing for obtaining angle data θ1 for correcting vertical trapezoidal distortion is performed. Do. That is, the microcomputer 25 employs the output of the first sensor unit 29A, performs distance measurement for each of the uppermost area and the lowermost area of the adjustment projection image, and calculates the distance between the uppermost area and the lowermost area and the distance measurement value. The angle data θ1 is calculated from the difference.

  Next, the microcomputer 25 executes a drawing process of the second adjustment projection image by the OSD circuit 28. As shown in FIG. 6B, the second adjustment projection image is a stripe image in which white vertical line regions and black vertical line regions are alternately formed. The data forming such an image remains as it is. It is not written in the image memory 21.

  Specifically, the microcomputer 25 (OSD circuit 28) writes video data for one horizontal line in the image memory 21. Then, the microcomputer 25 instructs the video signal processing circuit 23 to enlarge in the vertical direction. If the number of vertical pixels on one screen is 768, the enlargement ratio is 768 times. The video signal processing circuit 23 performs a process of multiplying the video data for one horizontal line by 768 in the vertical direction, and gives the video signal obtained by this process to the panel drivers 24R, 24G, and 24B. For example, the image signal may be given to only one panel driver 24G to project a green one-color stripe image.

  The microcomputer 25 employs the output of the second sensor unit 29B, performs distance measurement for each of the leftmost area and the rightmost area of the adjustment projection image, and calculates the distance between the leftmost area and the rightmost area and the distance measurement value. Angle data θ2 is calculated from the difference.

The microcomputer 25 performs trapezoidal distortion correction based on the first angle data θ1 and the second angle data θ2. The angle and the degree of trapezoidal distortion are in a proportional relationship. If the angle is known, it can be determined how much correction should be performed on the image. For example, the video signal processing circuit 23 receives the angle data from the microcomputer 25, and performs pixel interpolation of the input video data so as to have a trapezoidal distortion that is opposite to the trapezoidal distortion that is assumed to be caused by projection at the angle / Execute pixel thinning processing. When the focus adjustment and the trapezoidal distortion correction are completed, the driving unit is driven to return the cover 60 to the closed state.

  As described above, it is not necessary to write the entire projection image data for adjustment in the image memory 21, and only a part of the projection image data needs to be written. Therefore, the drawing time (data writing time) is remarkably increased. Therefore, the adjustment image can be projected quickly.

  Further, since the sensor 29 is covered with the cover 60, it is possible to prevent dust from adhering to the sensor 29, and it is possible to prevent erroneous detection of the sensor 29 due to dust adhering to the sensor 29 and to perform accurate focus adjustment. And trapezoidal distortion correction can be performed.

  In addition, when the sensor 29 captures an image, the cover 60 covering the sensor 29 is opened, so that even if the cover 60 is distorted or scratched or dust is attached to the cover 60, the sensor 29 is erroneously detected. Thus, focus adjustment and trapezoidal distortion correction can be performed more accurately.

  Further, since the cover 60 is closed except when the sensor 29 captures an image, it is possible to prevent dust from adhering to the sensor 29 as much as possible.

  Note that the focus adjustment and trapezoidal distortion correction methods described above are not limited in any way, and any method may be used. Further, although a transmissive liquid crystal projector has been shown as a projection display apparatus, a reflective liquid crystal projector may be used, and the present invention is not limited to a liquid crystal projector. It is good also as a type | mold video display apparatus.

  In this embodiment, the microcomputer 25 that performs overall control in the liquid crystal projector 30 performs adjustment control of the above-described setting during projection. However, a dedicated microcomputer is provided in the sensor 29, and focus adjustment and The microcomputer 25 may perform processing such as calculation of angle data, and the microcomputer 25 may allocate processing capacity for other processing. Moreover, not only a CCD line sensor but a planar CCD or the like may be used. Further, the present invention is not limited to displaying the first adjustment video and the second adjustment video separately.

  Further, the cover 60 is not limited to the cover 60 that can rotate as a closing member that covers the sensor 29, but may be configured by a slidable shutter, a blind that can be rotated about a plurality of axes, or the like. Further, the present invention is not limited to a projection display apparatus that performs both focus adjustment and trapezoidal distortion correction.

1 is an external perspective view of a liquid crystal projector according to an embodiment of the present invention. It is the block diagram which showed the optical system of the liquid crystal projector. It is the block diagram which showed the signal processing system of the liquid crystal projector. It is a schematic block diagram of the sensor of the liquid crystal projector. It is a figure which shows the open / close state of the cover of the liquid-crystal projector, the figure (a) shows the state which closed the cover, and the figure (b) shows the state which opened the cover. The figure (a) of the liquid crystal projector is an explanatory view showing the state of occurrence of vertical trapezoidal distortion, and the figure (b) is an explanatory view showing the state of occurrence of horizontal trapezoidal distortion. The figure (a) of the liquid crystal projector is an explanatory diagram showing that vertical trapezoidal distortion has occurred in the first adjustment projection image projected on the screen, and the figure (b) is projected on the screen. It is explanatory drawing which showed that horizontal trapezoid distortion had arisen in the 2nd projection image for adjustment.

Explanation of symbols

1 Light source 16 Projection lens 25 Microcomputer (control unit)
29 Sensor 31 Liquid crystal light valve 32 Liquid crystal light valve 33 Liquid crystal light valve 60 Cover (blocking means)

Claims (3)

In a projection display apparatus that modulates light emitted from a light source with a liquid crystal light valve and projects an image with a projection lens, a sensor that captures the projected image, contrast data based on the image data of the sensor, and / or A controller that calculates angle data and performs focus adjustment and / or trapezoidal distortion correction, a closing member that prevents dust from adhering to the sensor by covering the sensor, and moves the closing member to an open state And a driving means. The projection display apparatus according to claim 1, wherein the closing member is configured to be opened when the sensor captures a projected image. 3. The projection display apparatus according to claim 1, wherein the closing member is configured to be closed when the sensor does not capture the projected image.