JP2013168836A - Projection type image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type image display device capable of suppressing deterioration of image quality when contrast is improved.SOLUTION: A projection type image display device includes a dynamic iris control unit 30 which controls a first diaphragm mechanism 8, and a second diaphragm mechanism 20. The dynamic iris control unit 30 includes: a video analyzing unit 31 which analyzes a video signal; a diaphragm-video setting unit 32 which sets the diaphragm amount of the first diaphragm mechanism 8, the diaphragm amount of the second diaphragm mechanism 20, and a color balance correction value on the basis of analysis data analyzed by the video analyzing unit 31; and diaphragm drive units 33, 34 which output drive signals to the first diaphragm mechanism 8 and the second diaphragm mechanism 20 so that both have the diaphragm amount set by the diaphragm-video setting unit 32. Accordingly, contrast of an image can be improved and a clear image can be displayed.

Description

  The present invention relates to a projection type image display apparatus that projects an image on a screen or the like, and more particularly to a technique for improving image quality.

  A projection-type image display device that projects an image on a screen or the like needs to change the light amount of a video signal projected on the screen in order to adjust the contrast in accordance with ambient brightness. As a method for changing the light amount, it is known to adjust the light amount of the light source lamp. However, when the light amount of the light source lamp is adjusted, there is an adverse effect that the life of the light source lamp is shortened. In order to solve this problem, what has been conventionally described in, for example, Japanese Patent Application Laid-Open No. 2003-241311 (Patent Document 1) has been proposed. In Patent Document 1, it is disclosed that the brightness of an image projected on a screen is adjusted by adjusting a light amount by providing a light amount adjusting unit on at least one of an optical path and a projection unit.

JP 2003-241311 A

  However, in the conventional example disclosed in Patent Document 1 described above, although the color balance is prevented from being lost by appropriately setting the installation position of the light amount adjusting unit and adjusting the light amount, the light actually depends on the wavelength. In such a case, the color balance may be lost by controlling the light amount adjusting unit, and a clear image may not be displayed.

  Further, Patent Document 1 does not describe specific control for dynamic driving of an input video signal or interlocking of two light quantity adjustment units. That is, when the aperture is dynamically controlled according to the input video, the color balance may change dynamically depending on the scene, and there is a problem that the image quality deteriorates. There is no mention of solving the problem.

  The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a projection type image display apparatus capable of suppressing deterioration in image quality when improving contrast. It is in.

  In order to achieve the above object, according to the first aspect of the present invention, the amount of light emitted from the light source is controlled by the first diaphragm mechanism (8), and the amount of light passing through the projection lens is second. In the projection type image display apparatus that controls the first diaphragm mechanism and the second diaphragm mechanism in the projection type image display apparatus that controls the first diaphragm mechanism and the second diaphragm mechanism by controlling by the diaphragm mechanism (20) and projects the projected image from the projection lens. Is based on the analysis data analyzed by the video analysis unit (31) that analyzes the video signal, and the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, and the color balance correction value based on the analysis data. A setting unit (32) to be set, a diaphragm driving unit (33, 34) for outputting a driving signal to the first diaphragm mechanism and the second diaphragm mechanism so as to have the diaphragm amount set by the setting unit, and a setting unit Using the set color balance correction value, Characterized by comprising an image processing unit (35), for correcting the color balance of the item.

  The invention according to claim 2 has a correspondence table in which the setting unit associates the analysis data with the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, and the color balance correction value. When analysis data is given, referring to this correspondence table, the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, and the color balance correction value are set.

  According to a third aspect of the present invention, the setting unit sets a lightness correction value based on the analysis data, and corrects the lightness of the video signal.

  In the invention according to claim 4, the setting unit associates the analysis data with the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, the color balance correction value, and the brightness correction value. When the analysis data is given, referring to this correspondence table, the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, the color balance correction value, and the brightness correction value are set. It is characterized by.

  According to a fifth aspect of the present invention, the video analysis unit sets the analysis data based on a brightness histogram of an input signal.

  According to a sixth aspect of the present invention, the video analysis unit sets analysis data based on a peak value or an average value of a histogram.

  According to the present invention, when the diaphragm mechanism is controlled to improve the contrast of an image, it is possible to suppress deterioration in image quality by correcting the color balance.

It is explanatory drawing which shows typically the structure of the projection type image display apparatus which concerns on one Embodiment of this invention. It is a characteristic view which shows the relationship between aperture amount and chromaticity coordinates x and y. It is a block diagram which shows the detailed structure of a dynamic iris control part. It is a table which shows a response | compatibility with the 1st aperture value, 2nd aperture value, color balance correction value, and brightness correction value with respect to analysis data. It is a flowchart which shows the processing operation of the projection type image display apparatus which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram schematically showing the configuration of the projection display device according to the present embodiment. As shown in the figure, this projection type image display apparatus includes a discharge lamp 1 that irradiates light, a reflector 2 that has a reflecting surface that forms a paraboloid of revolution, and that reflects light emitted from the discharge lamp 1, and the reflector. 2 includes a cold filter 3, a first lens array 4, a first aperture mechanism 8, a second lens array 5, a polarization conversion element 6, and an overlapping lens 7 provided on the optical path of the light reflected by 2.

  The cold filter 3 removes ultraviolet rays and infrared rays contained in the light reflected by the reflector 2. The first lens array 4 has a rectangular shape similar to the display area of the reflective liquid crystal display elements 17b, 17g, and 17r, which are spatial modulation elements described later, so that the reflector 2 spatially divides the aperture from which the light beam is emitted. A plurality of shaped lens cells are two-dimensionally arranged.

The first lens array 4 condenses the illumination light on the lens cells of the second lens array 5 corresponding to the lens cells of the first lens array 4, and the first lens array 4 has a first lens on the second lens array 5. As many secondary light source images as the lens cells of the lens array 4 are formed.
The illumination light that has passed through the first lens array 4 is incident on the second lens array (fly eye lens) 5. For each lens cell of the second lens array, the second lens array 5 displays an image of the corresponding lens cell opening of the first lens array 4 on the display surface of the reflective liquid crystal display elements 17b, 17g, 17r. To form an image.

  A first diaphragm mechanism 8 is provided between the first lens array 4 and the second lens array 5. The first iris mechanism 8 has its iris amount controlled by the dynamic iris controller 30, and can adjust the contrast and brightness of the display image by the projection display device by blocking a part of the luminous flux of the illumination light. it can. The first diaphragm mechanism 8 is disposed in the vicinity of the second lens array 5 where the secondary light source image is formed.

  The illumination light emitted from the second lens array 5 is incident on the polarization conversion element 6. The polarization conversion element 6 is an optical element having a flat plate shape in which a plurality of polarization beam splitters are arranged in parallel, and converts incident light having a random polarization direction into polarized light having a certain polarization direction. Therefore, polarized light having a certain polarization direction is emitted from the polarization conversion element 6.

  Polarized light (referred to as P-polarized light) emitted from the polarization conversion element 6 is incident on the overlapping lens 7. The superposing lens 7 makes the center of the image of each lens cell of the first lens array 4 coincide with the center of the reflective liquid crystal display elements 17b, 17g, 17r, and the image of each lens cell of the first lens array 4 is The reflective liquid crystal display elements 17b, 17g, and 17r are adjusted so as to overlap each other on the display surface.

  The P-polarized light emitted from the overlapping lens 7 is separated into blue light and red / green light by the B / RG separation cross dichroic mirror 10. The optical path of the blue light is bent by the B mirror 11, passes through the blue field lens 14b, the blue WG-PBS 15b, and the blue wavelength plate 16b, and enters the blue liquid crystal display element 17b. Further, the S-polarized light component reflected and modulated by the blue liquid crystal display element 17 b is reflected by the blue WG-PBS 15 b and travels toward the cross dichroic prism 18.

  On the other hand, the red / green light separated by the B / RG separation cross dichroic mirror 10 has its optical path bent by the RG mirror 12 and separated by the RG dichroic mirror 13 into red light and green light. As in the case of blue light, red light and green light pass through field lenses 14r and 14g, WG-PBSs 15r and 15g, and wave plates 16r and 16g, respectively, and enter the reflective liquid crystal display elements 11r and 11g. Furthermore, the S-polarized light component reflected and modulated by the reflective liquid crystal display elements 17 r and 17 g is reflected by the WG-PBS 15 r and 15 g and travels toward the cross dichroic prism 18.

  Then, the three color lights are combined in the cross dichroic prism 18 and projected onto the screen by the projection lens 19. The projection lens 19 has a second diaphragm mechanism 20, and the diaphragm amount of the second diaphragm mechanism 20 is controlled by a dynamic iris control unit 30.

  In the above configuration, when various wavelengths exist in the light and the spread of the light is not uniform for each wavelength, the aperture amount of the first aperture mechanism 8 and the second aperture mechanism 20 is changed. The color balance of the video signal projected from the projection lens 19 may be lost.

  FIG. 2 is a characteristic diagram showing changes in the chromaticity coordinates x, y with respect to the aperture amount, and the chromaticity coordinates x, y change as the aperture amount changes. Specifically, when the aperture amount increases, both the chromaticity coordinates x and y tend to increase. Therefore, when the diaphragm amounts of the first diaphragm mechanism 8 and the second diaphragm mechanism 20 are dynamically controlled according to the video signal, the color balance and brightness of the video signal are also dynamically corrected in conjunction with this. There is a need to. In the present embodiment, the dynamic iris control unit 30 sets the aperture amounts of the first aperture mechanism 8 and the second aperture mechanism 20, respectively, and further sets the color balance correction value and the brightness correction value, thereby reducing the aperture. A change in color balance and a change in lightness caused by changing the amount are suppressed, and deterioration in image quality is prevented.

  Next, a detailed configuration of the dynamic iris control unit 30 illustrated in FIG. 1 will be described. FIG. 3 is a block diagram illustrating a configuration of the dynamic iris control unit 30. As illustrated, the dynamic iris control unit 30 includes a video analysis unit 31, a diaphragm / video setting unit 32, a first diaphragm driving unit 33, a second diaphragm driving unit 34, and a video processing unit 35. ing.

  The video analysis unit 31 analyzes input video signals and creates analysis data. For example, brightness can be extracted from the video signal, a histogram for brightness can be calculated, and the maximum value of brightness can be used as analysis data from the histogram, or an average value of brightness can be used as analysis data. Furthermore, the degree of lightness distribution can be obtained and used as analysis data.

  For example, as shown in FIG. 3, the aperture / image setting unit 32 displays a correspondence table of the aperture amount of the first aperture mechanism 8, the aperture amount of the second aperture mechanism 20, the color balance correction value, and the brightness correction value with respect to the analysis data. I have. When the analysis data is output from the video analysis unit 31, the analysis data is applied to the correspondence table, whereby the aperture amount of the first aperture mechanism 8, the aperture amount of the second aperture mechanism 20, and the color balance correction. The aperture value of the first aperture mechanism 8 is output to the first aperture drive unit 33, and the aperture level of the second aperture mechanism 20 is output to the second aperture drive unit 34. Further, the color balance correction value and the brightness correction value are output to the video processing unit 35.

  Here, the “aperture amount” is a displacement amount to which the opening degree of the first and second aperture mechanisms 8 and 20 is changed, and the “aperture level” is the first and second aperture mechanisms 8. , 20 and the degree of opening. Accordingly, the aperture level is determined by the aperture initial value and the aperture amount. That is, since the aperture / image setting unit 32 is provided with the aperture initial value data, the aperture level is set based on the aperture initial value and the aperture amount obtained by referring to the correspondence table, and the first aperture mechanism. 8 is output to the first aperture driving unit 33, and the aperture level of the second aperture mechanism 20 is output to the second aperture driving unit 34.

  As described above, since there are two diaphragm mechanisms, the initial aperture value is taken into account, depending on the aperture state of one of the diaphragm mechanisms, even if the diaphragm level of the other diaphragm mechanism is changed, the amount of light is adjusted. This is because the influence may not occur. That is, it is considered to set so that no dead zone is formed in each diaphragm mechanism.

  Next, the processing operation of the projection type image display apparatus according to the present embodiment configured as described above will be described with reference to the flowchart shown in FIG.

  First, in step S11, the video analysis unit 31 acquires a video signal. Thereafter, in step S12, the video analysis unit 31 analyzes the acquired video signal and creates analysis data. In this embodiment, as an example of analysis data, a histogram for brightness is created, and the brightness that is the peak value of the histogram is used as analysis data. The analysis data is not limited to the peak value, and various data such as an average value of brightness can be used.

  In step S <b> 13, the aperture / image setting unit 32 sets the aperture amount of the first aperture mechanism 8 and the aperture amount of the second aperture mechanism 20 based on the analysis data obtained by the image analysis unit 31. This process can be determined by applying the analysis data to the correspondence table shown in FIG. Specifically, when the analysis data is A0, the aperture amount of the first aperture mechanism 8 is S10, and the aperture amount of the second aperture mechanism 20 is S20.

  In step S14, the aperture / video setting unit 32 sets a color balance correction value and a brightness correction value. This process can be determined by applying the analysis data to the correspondence table shown in FIG. Specifically, when the analysis data is A0, the color balance correction value is C0, and the brightness correction value is Y0. In the processing of steps S13 and S14, an example in which each data is acquired using the correspondence table is shown, but each data may be calculated by calculation. That is, when the analysis data is determined, the analysis data is applied to a predetermined arithmetic expression to thereby reduce the aperture amount of the first aperture mechanism 8, the aperture amount of the second aperture mechanism 20, the color balance correction value, and the brightness correction. A value may be set.

  Note that either the process of step S13 or the process of step S14 may be performed first. That is, the process of step S14 may be performed first, and then the process of step S13 may be performed.

  In step S15, the first aperture driving unit 33 outputs a control signal to the first aperture mechanism 8, and controls the aperture amount of the first aperture mechanism 8 to be the aperture amount set in the process of step S13. . Similarly, the second aperture driving unit 34 outputs a control signal to the second aperture mechanism 20 so as to control the aperture amount of the second aperture mechanism 20 to the aperture amount set in step S13. In step S <b> 16, the video processing unit 35 corrects the color balance of the video based on the color balance correction value, and further corrects the brightness of the video based on the brightness correction value.

  Note that either the process of step S15 or the process of step S16 may be performed first. That is, the process of step S16 may be executed first, and then the process of step S15 may be executed.

  Thus, by controlling the first diaphragm mechanism 8 or the second diaphragm mechanism based on the analysis data, the contrast of the image can be increased, and the color balance collapse caused by controlling the diaphragm mechanism can be prevented. .

  Here, as an example of color balance correction, for example, correction may be performed by calculation of a 3 × 3 matrix. Examples of brightness correction include, for example, adding an offset to a video signal or multiplying a gain that varies linearly. Another example is correcting the lightness using a gamma curve that changes in a curved manner. Then, the video signal that has been subjected to video processing by these corrections is output from the video processing unit 35 to a subsequent processing device.

  Note that the processing of the dynamic iris control unit 30 described above is performed in conjunction with the video signal, and thus is preferably processed for each frame of the video. However, when the amount of processing is large, the processing may be performed over a plurality of frames.

  In this way, in the projection type image display apparatus according to the present embodiment, a histogram of the brightness of the video signal is created, analysis data of this histogram is obtained, the aperture amount of the first aperture mechanism 8 for the analysis data, the second When a correspondence table showing a correspondence relationship between the aperture amount of the aperture mechanism 20, the color balance correction value, and the brightness correction value is created in advance, and the video signal analysis data is created by the video analysis unit 31. By applying this analysis data to the correspondence table, the aperture amount of the first aperture mechanism 8, the aperture amount of the second aperture mechanism 20, the color balance correction value, and the brightness correction value are set. Based on these, the aperture level of the first aperture mechanism 8 and the aperture level of the second aperture mechanism are controlled, and the color balance and brightness of the video signal are further corrected.

  Accordingly, the contrast of the video can be improved, and further, the color balance and brightness of the video are corrected, so that it is possible to prevent the color balance from being lost and the brightness from being changed due to the change of the aperture level. Even when the aperture levels of the first and second aperture mechanisms 8 and 20 are changed, it is possible to project a clear image on a screen or the like without being affected by the change in the aperture level.

  Furthermore, since a brightness histogram is used as the analysis data, it is possible to control an appropriate aperture amount in accordance with the brightness balance.

  As mentioned above, although the projection type image display apparatus of the present invention has been described based on the illustrated embodiment, the present invention is not limited to this, and the configuration of each part is an arbitrary configuration having the same function. Can be replaced.

  For example, in the above-described embodiment, an example has been described in which the color balance correction value and the brightness correction value are set based on the analysis data, and the color balance and the brightness of the video signal are corrected based on these values. However, the present invention is not limited to this, and it is possible to adopt a configuration in which only the color balance correction value is corrected and the brightness is not corrected.

  The present invention can be used to improve the contrast of an image by controlling the aperture mechanism without degrading the image.

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Reflector 3 Cold filter 4 1st lens array 5 2nd lens array 6 Polarization conversion element 7 Lens 8 1st aperture mechanism 18 Cross dichroic prism 19 Projection lens 20 2nd aperture mechanism 30 Dynamic iris control part 31 Image | video Analysis unit 32 Aperture / video setting unit 33 First aperture drive unit 34 Second aperture drive unit 35 Video processing unit

Claims (6)

A projection type in which the amount of light emitted from the light source is controlled by a first diaphragm mechanism, and further, the amount of light passing through the projection lens is controlled by a second diaphragm mechanism, and the projected image is projected onto the screen from the projection lens. In an image display device,
A controller for controlling the first diaphragm mechanism and the second diaphragm mechanism;
The controller is
A video analysis unit for analyzing the video signal;
A setting unit for setting the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, and a color balance correction value based on the analysis data analyzed by the video analysis unit;
An aperture drive unit that outputs a drive signal to the first aperture mechanism and the second aperture mechanism so as to achieve the aperture amount set by the setting unit;
A video processing unit that corrects the color balance of the video signal using the color balance correction value set in the setting unit;
A projection-type image display device comprising:   The setting unit has a correspondence table in which the analysis data is associated with the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, and the color balance correction value, and the analysis data is given. 2. The projection according to claim 1, wherein, with reference to the correspondence table, the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, and the color balance correction value are set. Type image display device.   The projection type image display apparatus according to claim 1, wherein the setting unit sets a brightness correction value based on the analysis data, and the video processing unit corrects the brightness of the video signal.   The setting unit includes a correspondence table that associates the analysis data with the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, the color balance correction value, and the brightness correction value. When the analysis data is given, referring to the correspondence table, the aperture amount of the first aperture mechanism, the aperture amount of the second aperture mechanism, the color balance correction value, and the brightness correction value are set. The projection type image display apparatus according to claim 3, wherein   5. The projection type image display device according to claim 1, wherein the video analysis unit sets the analysis data based on a brightness histogram of an input signal. 6.   The projection type image display device according to claim 5, wherein the video analysis unit sets analysis data based on a peak value or an average value of the histogram.

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