JP2009175574A - Projector and positional deviation correcting method for optical modulation element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To dynamically correct the positional deviations of respective optical modulation elements corresponding to the respective color components of a projector, and to enable positional deviation correction with a simple configuration and a small operation amount. <P>SOLUTION: A projector includes: optical sensors OS1 to OS4 which detect the light quantity of measurement light for obtaining the positional deviation amounts of the respective optical modulation elements 150R, 150G and 150B corresponding to a plurality of color components (RGB), output from the respective optical modulation elements, in a prescribed position between the respective optical modulation elements and the projection optical system, when the measurement light is given to the respective optical modulation elements; a positional deviation detecting section which detects the positional deviation amounts and positional deviation directions of the respective optical modulation elements, on the basis of the light quantities detected by the optical sensors; and a positional deviation correction control section which corrects the positional deviations of the respective optical modulation elements, on the basis of the positional deviation amounts and positional deviation directions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a projector having a function of correcting a positional deviation of each light modulation element corresponding to a plurality of color components and a method for correcting a positional deviation of the light modulation element.

  A so-called three-plate projector having three light modulation elements (for example, a liquid crystal panel) corresponding to a plurality of color components (red, green, and blue) is known. In such a three-plate projector, the light modulation elements corresponding to red (R), green (G), and blue (B) may be displaced due to changes over time. If the position of the light modulation element is deviated, the position of the projected image is deviated from the required display position such as a screen. Furthermore, if the position of each light modulation element corresponding to RGB is relatively shifted, a shift occurs in the corresponding pixel of each light modulation element corresponding to RGB, leading to a reduction in image quality of the projected image. Recently, since the resolution of projectors is becoming higher and higher, the pixel shift of each light modulation element appears more prominently in the projected image.

  In order to eliminate such a positional shift of each light modulation element, it is necessary to adjust the position so that each RGB light modulation element is in an appropriate position. Various techniques for adjusting the positions of the RGB light modulation elements so as to be in appropriate positions have been conventionally proposed (see, for example, Patent Document 1).

  The technique disclosed in Patent Document 1 (hereinafter referred to as the prior art) provides a position adjustment signal to each liquid crystal panel as each light modulation element corresponding to RGB, and a position adjustment signal for each liquid crystal panel by a projector. The line is swept at a constant speed on the screen, the time from the start of sweeping of the line to the specific point on the screen is measured, and the position of each liquid crystal panel is adjusted based on the measurement result. It is.

JP-A-6-165224

  According to the above-described conventional technology, it is possible to quantify the relative displacement of each liquid crystal panel corresponding to RGB. However, the prior art has a signal generator for displaying bright lines that are swept at a constant speed on the screen, and the time from the start of sweeping of the bright lines to the time when the light detection means detects the light of each liquid crystal panel corresponding to RGB. It requires a large component such as a displacement detector that obtains the time difference and detects the position deviation based on the obtained time difference, and the calculation for detecting the position deviation is not easy.

  Further, it is assumed that the position adjustment in the prior art is performed in the production process of the projector. However, when the power is actually turned on when using the projector, the relative position of each liquid crystal panel may be shifted due to the influence of thermal expansion caused by the light source. Further, there may be a positional shift in each liquid crystal panel due to a change over time due to long-term use of the projector. However, the above-described conventional technology has a problem that it is difficult to cope with a positional shift that occurs when the projector is used.

In addition to the above-described conventional techniques, a technique is also proposed in which an image projected on a screen is picked up by an image pickup means such as a camera, and the picked-up image data obtained thereby is processed to correct misalignment of each liquid crystal panel. However, such a technique requires an image pickup means for picking up an image on the screen, and needs to perform complicated data processing for processing image data obtained from the image pickup means. Therefore, there is a problem that the cost is high both in terms of hardware and software.

  The present invention provides a projector and a light modulation capable of dynamically performing positional deviation correction of each light modulation element corresponding to each color component of the projector, and capable of performing positional deviation correction with a simple configuration and a small amount of calculation. An object of the present invention is to provide a method for correcting an element misalignment.

  A projector according to the present invention includes a plurality of light modulation elements corresponding to a plurality of color components, and a combination optical system that combines the color lights output from the light modulation elements of the plurality of light modulation elements and emits them as image light. A projector optical system for projecting image light emitted from the combining optical system onto a projection surface, and measuring light for obtaining a positional deviation amount of each light modulation element. An optical sensor for detecting the light quantity of the measurement light output from each light modulation element at a predetermined position between each light modulation element and the projection optical system when applied to the element, and detected by the light sensor A misregistration detection unit that detects a misregistration amount and a misregistration direction of each of the light modulation elements based on the amount of light that has been transmitted; No position to do And having a correction control unit.

  As described above, according to the projector of the present invention, the position shift detection unit that detects the position shift amount and the position shift direction of each light modulation element based on the light amount detected by the light sensor, and the position shift of each light modulation element. Since the position shift correction control unit for performing the position shift correction control of each light modulation element based on the amount and the position shift direction is provided, the position shift correction of each light modulation element can be dynamically performed. . Thereby, according to the projector of the present invention, it is possible to correct the positional deviation of each light modulation element even at an arbitrary time after the position adjustment is performed in the production process of the projector.

  In addition, the projector according to the present invention obtains the positional deviation amount of each light modulation element based on the light amount detected by the optical sensor provided in the housing of the projector, so that the image displayed on the screen is displayed. Unlike the method of calculating the amount of positional deviation by processing captured image data obtained by capturing with a camera, an imaging device such as a camera can be dispensed with and complicated image data processing is dispensed with. Can do. As a result, according to the projector of the present invention, it is possible to correct the positional deviation of the light modulation element with a simple configuration and with a small amount of calculation, and the cost can be kept low both in terms of hardware and software.

  Note that the measurement light for obtaining the positional deviation amount of each light modulation element is an area that is not used for image display that exists outside the area that each light modulation element uses for actual image display (referred to as an image formation area). It is preferable to use (referred to as a non-image forming area) for transmitting measurement light. Such a non-image forming area is generally present in the light modulation element. If there is no non-image forming area, one outermost pixel of the image forming area is used for transmitting measurement light. Even if it is used as, it can be similarly implemented.

In the projector according to the aspect of the invention, a plurality of the optical sensors may be provided, and the plurality of optical sensors may detect a light amount corresponding to a lateral displacement amount and a longitudinal displacement amount of each light modulation element. Preferably they are arranged.
As a result, it is possible to determine the horizontal and vertical misalignment amounts of each light modulation element, and the horizontal and vertical positions of each light modulation element based on the obtained horizontal and vertical misalignment amounts. The deviation can be corrected.

In the projector according to the aspect of the invention, the amount of misalignment and the direction of misalignment of each of the light modulation elements may include the amount of light detected by the light sensor when each of the light modulation elements is in an ideal position, It is preferable that the detection is performed based on a difference from the light amount detected by the optical sensor at the time of execution of the positional deviation amount acquisition process.

  As described above, the difference between the ideal light amount and the light amount obtained at the time of execution of the positional deviation amount acquisition process is obtained, and the positional deviation amount and the positional deviation direction are detected based on the obtained difference. Thus, it is possible to detect the position shift amount and the position shift direction of the light modulation element appropriately with simple calculation.

In the projector according to the aspect of the invention, it is preferable that the optical sensor is attached to an optical sensor attachment member for attaching the optical sensor.
Thus, by attaching the optical sensor to the optical sensor attachment member, the optical sensor can be easily and appropriately supported. In addition, since the optical sensor mounting member can be a component independent of other optical components of the projector, it can be installed at a position where the amount of measurement light output from each light modulation element can be optimally detected. As a result, the positional deviation amount of each light modulation element can be obtained with high accuracy.

In the projector according to the aspect of the invention, it is preferable that the optical sensor mounting member is provided between the combining optical system and the projection optical system.
As described above, by providing the optical sensor mounting member between the combining optical system and the projection optical system, it is possible to appropriately detect the amount of measurement light output from each light modulation element.

In the projector according to the aspect of the invention, it is preferable that the optical sensor mounting member is a frame-shaped member having an opening that can transmit image light emitted from the combining optical system.
With the optical sensor mounting plate having such a configuration, the image light combined by the combining optical system is displayed as an appropriate image on the screen without being blocked by the optical sensor mounting member.

In the projector according to the aspect of the invention, it is preferable that the frame member is made of a material having a light shielding effect.
By providing a light shielding effect to the frame-shaped member of the optical sensor mounting plate, when the projector is projecting an image, for example, image light emitted from the combining optical system is irregularly reflected by another member inside the projector and again. It can be expected to suppress the incident on the combining optical system and other optical systems.

In the projector according to the aspect of the invention, when the projector has a light diffusing unit between the projection optical system and the combining optical system and forms an intermediate image in the light diffusing unit, the optical sensor It is preferable to be provided in the light diffusion part.
In the projector having such a configuration, it is possible to provide a light sensor in the light diffusing unit, and thus a dedicated light sensor mounting plate can be dispensed with.

  In the projector according to the aspect of the invention, at least detection of the light amount of the measurement light among detection of the light amount of the measurement light, detection of a positional deviation amount and a positional deviation direction of each light modulation element, and positional deviation correction control of each light modulation element. Is preferably performed in a time-sharing manner for each of the light modulation elements.

  This is because when a plurality of color components are red (R), green (G), and blue (B), the light modulation elements corresponding to RGB are time-divided for each light modulation element corresponding to each color of RGB. This means that the light amount of the measurement light is sequentially detected, whereby the light amount of the measurement light corresponding to each of RGB can be detected easily and reliably.

In the projector according to the aspect of the invention, a plurality of light modulation elements corresponding to a plurality of color components, and a combination optical system that combines the color lights output from the light modulation elements of the plurality of light modulation elements and emits them as image light. A light modulation element position correction method for correcting a position shift of each light modulation element in a projector having a projection optical system that projects image light emitted from the synthesis optical system onto a projection surface, When the measurement light for obtaining the positional deviation amount of each light modulation element is given to each light modulation element, the amount of the measurement light output from each light modulation element is set to each light modulation element and the projection. A step of detecting by an optical sensor provided at a predetermined position between the optical system and a step of detecting a positional shift amount and a positional shift direction of each of the light modulation elements based on a light amount detected by the optical sensor; , On the basis of the positional deviation amount and the positional deviation direction, characterized in that a step of performing positional deviation correction control of the respective light modulating elements.

  The projector of the present invention can be realized by adopting the light modulation element misalignment correcting method of the present invention for the projector. Note that the positional deviation correction method for the light modulation element of the present invention preferably has the same characteristics as the projector of the present invention.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a plan view showing the main configuration of an optical system in a projector according to an embodiment of the invention. As shown in FIG. 1, the projector of the present invention includes an image forming unit 100, a projection optical system 200 that projects image light emitted from the image forming unit 100 onto a screen SCR as a projection surface, and a light detection unit 300 ( Details will be described later).

  The image forming unit 100 includes first to third light source devices 110 to 130, light modulation elements 150R, 150G, and 150B corresponding to the first to third light source devices 110 to 130, and light modulation elements 150R, 150G, and 150B. And a cross dichroic prism 160 as a synthesizing optical system for synthesizing the color lights modulated in (1). In the projector according to the embodiment, it is assumed that the light modulation elements 150R, 150G, and 150B are light modulation elements (liquid crystal panels) using liquid crystals.

  The first light source device 110 includes a red light source R composed of a plurality of red LEDs that emit red light, a plurality of condensing lenses 111 provided corresponding to the plurality of red LEDs constituting the red light source R, and a rod. An integrator 112 and a condenser lens 113 provided on the output side of the rod integrator 112 are included.

  The second light source device 120 includes a green light source G composed of a plurality of green LEDs that emit green light, and a plurality of condensing lenses 121 provided corresponding to the plurality of green LEDs constituting the green light source G. The rod integrator 122 and the condenser lens 123 provided on the output side of the rod integrator 122 are included.

  In addition, the third light source device 130 includes a blue light source B composed of a plurality of blue LEDs that emit blue light, and a plurality of condenser lenses 131 provided corresponding to the plurality of green LEDs constituting the blue light source B. The rod integrator 132 and the condenser lens 133 provided on the output side of the rod integrator 132 are included.

  The light source may be one light source capable of outputting light including red light, green light, and blue light. In this case, separation optics that separates light from the light source into red light, green light, and blue light. It becomes the composition which has a system.

Further, the projector according to the embodiment is provided with a misalignment correcting unit (not shown) for correcting misalignment of each of the light modulation elements 150R, 150G, and 150B. As shown in FIGS. 2A, 2B, and 2C, in the projector according to the embodiment, the positional deviation correction unit is configured to place the light modulation elements 150R, 150G, and 150B in the horizontal direction of the light modulation elements. It is assumed that the position adjustment mechanism can move in the (x direction) and the vertical direction (y direction), for example, with a minute movement unit of less than one pixel.

  The position adjustment mechanism of the light modulation element is not particularly limited as long as each light modulation element can be moved in a minute movement unit, for example, a position adjustment mechanism using a piezo element, etc. A known position adjusting mechanism can be employed.

  FIG. 3 is a diagram illustrating a configuration example of the light detection unit 300 used in the projector according to the embodiment. As shown in FIG. 3, the light detection unit 300 includes a plurality (four) of light sensors OS1 to OS4 and a light sensor mounting plate 310 to which the light sensors OS1 to OS4 are attached. .

  The optical sensor mounting plate 310 has a frame shape having a rectangular opening 320. Note that the horizontal dimension a and the vertical dimension b of the opening 320 have dimensions equivalent to the horizontal and vertical dimensions of the image light synthesized by the cross dichroic prism 160. The synthesized image light can pass through without being blocked.

  Further, the material of the optical sensor mounting plate 310 is not particularly limited, but the projector according to the embodiment uses a material having a light shielding effect and has a function as a light shielding plate. To do. Since the optical sensor mounting plate 310 has a function as a light shielding plate, when the projector is projecting an image, for example, image light emitted from the cross dichroic prism 160 is irregularly reflected by other members inside the projector. An effect of suppressing the incident on the cross dichroic prism and other optical elements can be expected.

  As shown in FIG. 3, the optical sensors OS <b> 1 to OS <b> 4 are attached at positions along the sides on the opening 320 side of the sensor attachment plate 310 and at the center of each side. Of the optical sensors OS1 to OS4, the optical sensors OS1 and OS2 are optical sensors for detecting displacement in the lateral direction (x direction in FIG. 2) of the respective light modulation elements 150R, 150G, and 150B. OS4 is an optical sensor for detecting displacement in the vertical direction (y direction in FIG. 2) of each of the light modulation elements 150R, 150G, and 150B.

  FIG. 4 is a perspective view for explaining the positional relationship between the cross dichroic prism 160 and the light detection unit 300. The light sensor attachment 310 of the light detection unit 300 is installed so that the image light emitted from the cross dichroic prism 160 can pass through the opening 320 without being blocked.

  By the way, the light (referred to as measurement light) for obtaining the positional deviation amounts of the light modulation elements 150R, 150G, and 150B is obtained from the LED light sources of the light source devices 110, 120, and 130 (see FIG. 1) of the projector. The light from each LED light source is provided to the corresponding light modulation element. Each of the light modulation elements 150R, 150G, and 150B has an area (non-image forming area) that is not used for actual image display by a few pixels outside the area that is used for actual image display (image formation area). Therefore, it is preferable to use this non-image forming area for transmitting measurement light. If there is no non-image forming area, the outermost one pixel of the image forming area can be used for transmitting measurement light.

FIG. 5 is a diagram illustrating a configuration of a light modulation element misalignment correction processing apparatus in the projector according to the embodiment. As shown in FIG. 5, the light modulation element misalignment correction processing apparatus 500 includes a misalignment detection unit 510 and a misalignment correction control unit 520.

  The positional deviation detection unit 510 adjusts the position of each light modulation element, and the amount of light detected by each of the optical sensors OS1 to OS4 (referred to as measured light amount) and the ideal amount of light (ideal light amount) stored in the storage unit 600. And a function of detecting the positional deviation amount and the positional deviation direction of each of the light modulation elements 150R, 150G, and 150B based on the obtained difference.

The misregistration correction control unit 520 has a function of outputting a misregistration correction signal for controlling the misregistration correction means based on the misregistration amount and the misregistration direction obtained by the misregistration detection unit 510. Yes.
In the projector according to the embodiment, the position deviation correction unit is a position adjustment mechanism that can move each of the light modulation elements 150R, 150G, and 150B in minute units of movement in the horizontal and vertical directions, as described above. It is said.

  Next, a method for correcting the positional deviation of the light modulation element in the projector according to the embodiment will be specifically described. First, the amount of light detected by each optical sensor when the relative position of each optical modulation element 150R, 150G, 150B is an ideal position is determined for each optical modulation element. Then, the obtained detected light amount is stored in the storage unit 600 as an ideal light amount. Note that “the relative position of each light modulation element 150R, 150G, 150B is an ideal position” means that the light modulation element 150R corresponding to R and B is based on the position of the light modulation element 150G corresponding to G. , 150B is assumed to be a position when appropriately set.

  Here, when the relative positions of the light modulation elements 150R, 150G, and 150B are ideal positions, for example, the light amounts detected by the light sensors OS1 to OS4 for the light modulation element 150G corresponding to G are as follows. Assuming that the optical sensor OS1 is L1, the optical sensor OS2 is L2, the optical sensor OS3 is L3, and the optical sensor OS4 is L4, the ideal light amount detected by the optical sensors OS1 to OS4 for the optical modulation element 150G. Is stored in the storage unit 600. Similarly, for the light modulation elements 150R and 150B corresponding to R, the ideal light amounts detected by the respective optical sensors OS1 to OS4 are measured and stored in the storage unit 600.

  For example, when the position of each light modulation element is adjusted when the projector is used for a predetermined period, the position adjustment of each light modulation element can be performed by setting the position adjustment mode.

FIG. 6 is a flowchart showing a procedure of processing executed when the position adjustment mode is set. When setting the position adjustment mode, as shown in FIG. 6, first, measurement light is emitted (step S1), and each of the optical sensors OS1 to OS4 detects the amount of light (step S2). Then, the positional deviation detection unit 510 compares the light amount (measured light amount) detected by each of the optical sensors OS1 to OS4 with the ideal light amounts L1 to L4 to obtain a difference between the two (step S3), and the obtained difference. Based on the above, the amount of displacement and the displacement direction of each of the light modulation elements 150R, 150G, 150B are detected (step S4). Subsequently, the misregistration correction control unit 520 controls misregistration correction means based on the misregistration amount and misregistration direction detected by the misregistration detection unit 510 (step S5). As a result, the positional deviation correction is performed on the light modulation element in which the positional deviation occurs.
In this way, the positional deviation correction is performed on the light modulation element in which the positional deviation occurs, so that the relative position of each of the light modulation elements 150R, 150G, and 150B becomes an ideal position. Accordingly, there is no displacement of the corresponding pixels between the light modulation elements, and the image displayed on the screen can be of high quality.

  In the processing of steps S1 to S5, it is preferable to detect at least the amount of measurement light (step S1) in a time division manner for each of the light modulation elements 150R, 150G, and 150B. Thereby, the light quantity detection with respect to each of the light modulation elements 150R, 150G, and 150B can be appropriately performed. In the projector according to the embodiment, not only the detection of the light amount of the measurement light (step S1) but also all the processing of steps S1 to S5 are performed in a time division manner for each of the light modulation elements 150R, 150G, and 150B. . Here, it is assumed that the positional deviation correction process for the light modulation element 150G corresponding to G is performed first, and the positional deviation correction process for G for the light modulation element 150G will be described below.

  First, measurement light is applied to the light modulation element 150G. When the optical sensors OS1 to OS4 detect the light quantity of the measurement light output from the light modulation element 150G, the positional deviation detection unit 510 detects the positional deviation amount and the positional deviation direction based on the detected light quantity (actually measured light quantity). To do. The detection of the amount of displacement and the direction of displacement is performed as follows.

  Assume that the actually measured light amounts detected by the optical sensors OS1 to OS4 are L1 'in the optical sensor OS1, L2' in the optical sensor OS2, L3 'in the optical sensor OS3, and L4' in the optical sensor OS4. The positional deviation detection unit 510 calculates the difference between the actually measured light amounts L1 ′, L2 ′, L3 ′, and L4 ′ and the ideal light amounts L1, L2, L3, and L4 in the light modulation element 150G stored in the storage unit 600. Thus, the amount of displacement and the direction of displacement of the light modulation element 150G are detected from the difference.

  For example, as a result of taking the difference between the actually measured light amount L1 ′ by the optical sensor OS1 and the ideal light amount L1, L1 ′ = L1 and the difference between the actually measured light amount L2 ′ by the optical sensor OS1 and the ideal light amount L2 is obtained. As a result, if L2 ′ = L2, the amount of positional deviation in the horizontal direction (arrow x′-x axis direction in FIG. 4) is zero. In this case, the light modulation element 150G is in the horizontal direction. It is determined that the position is an ideal position.

  Further, as a result of taking the difference between the actually measured light amount L3 ′ by the optical sensor OS3 and the ideal light amount L3, L3 ′ = L3 and the difference between the actually measured light amount L4 ′ by the optical sensor OS4 and the ideal light amount L4 was obtained. As a result, if L4 ′ = L4, the amount of displacement in the vertical direction (arrow y′-y-axis direction in FIG. 4) is zero. In this case, the light modulation element 150G is It is determined that the position is an ideal position.

  On the other hand, as a result of taking the difference between the measured light quantity L1 ′ detected by the optical sensor OS1 and the ideal light quantity L1, the measured light quantity L1 ′ is larger than the ideal light quantity L1, and the measured light quantity detected by the optical sensor OS2. If the measured light amount L2 ′ is smaller than the ideal light amount L2 as a result of taking the difference between L2 ′ and the ideal light amount L2, it is determined that the light modulation element 150G is displaced in the lateral direction. . In this case, it is determined that there is a positional shift in the left direction (arrow x 'direction) shown in FIG. Further, the amount of positional deviation at that time can be obtained from the magnitude of the difference at that time.

  When the misregistration detection unit 510 detects the misregistration amount and misregistration direction in this way, the misregistration amount and misregistration direction detected are given to the misregistration correction control unit 520. The positional deviation correction control unit 520 outputs a positional deviation correction signal based on the positional deviation amount and the positional deviation direction given from the positional deviation detection unit 510 to the positional deviation correction means.

For example, in the positional deviation detection unit 510, as described above, when the actual measurement light amount L1 ′ is larger than the ideal light amount L1 and the actual measurement light amount L2 ′ is smaller than the ideal light amount L2, the positional deviation detection unit 510 starts from the positional deviation detection unit 510. , A displacement amount and a displacement direction corresponding to the obtained difference are given. Thereby, the positional deviation correction control unit 520 controls the positional adjustment mechanism corresponding to the light modulation element 150G based on the positional deviation amount and the positional deviation direction given from the positional deviation detection unit 510. In this case, since the light modulation element 150G is shifted by a predetermined positional shift amount in the direction of the arrow x ′ in FIG. 4, the positional shift correction control unit 520 moves the light modulation element 150G in the direction of the arrow x in FIG. A position deviation correction signal that is moved by an amount corresponding to the amount is output to a position adjustment mechanism for the light modulation element 150G. Thereby, the light modulation element 150G is controlled by the position adjustment mechanism so as to move in the direction of the arrow x in FIG.

  Note that when the position adjustment mechanism performs control to move the light modulation element 150G in the direction of the arrow x in FIG. 4, there may be a case where a vertical position shift may newly occur. It is determined whether or not there is (determination of whether or not L3 ′ = L3, L4 ′ = L4), and if a vertical misalignment has newly occurred, the vertical misalignment occurs. It is preferable that correction is also performed, and finally, misregistration correction is performed so that L1 ′ = L1, L2 ′ = L2, L3 ′ = L3, L4 ′ = L4.

  As described above, when the positional deviation correction for the light modulation element 150G corresponding to G is completed, the positional deviation correction for the light modulation element 150R corresponding to R is performed, and the positional deviation correction for the light modulation element 150R is performed. When the correction is completed, the positional deviation correction for the light modulation element 150B corresponding to B is subsequently performed. The positional deviation correction for the light modulation elements 150R and 150B corresponding to R and B can be performed in the same manner as in the case of the light modulation element 150G corresponding to G.

  In this way, by performing positional deviation correction for each of the light modulation elements 150R, 150G, and 150B, there is no deviation of the corresponding pixels in each of the light modulation elements 150R, 150G, and 150B, and an image displayed on the screen SCR. Can be of high quality.

  The positional deviation correction of each of the light modulation elements 150R, 150G, and 150B is such that the actually measured light amount matches the ideal light amount, that is, L1 ′ = L1, L2 ′ = L2, L3 ′ = L3, L4 ′ = L4. Sometimes it is preferable to end the misalignment correction, but when a threshold value is set for the difference between the measured light amount and the ideal light amount, and the difference between the measured light amount and the ideal light amount is equal to or less than the threshold value Alternatively, the positional deviation correction may be completed.

  By the way, the positional deviation correction described above can be performed not only when the projector is used for a predetermined period but also when the projector is used. In particular, when starting up the projector, the light modulation element may be displaced due to a sudden temperature change due to heat or the like for about several tens of minutes after the start of power-on for starting. It is preferable to perform misalignment correction when doing so. As described above, it is effective to perform misalignment correction when using the projector to maintain the quality of the displayed image.

  The present invention is not limited to the above-described embodiment, and modifications such as the following (1) to (9) are possible without departing from the gist of the present invention.

(1) In the above-described embodiment, the outer shape of the optical sensor mounting plate 310 is rectangular. However, if the opening 320 has a shape corresponding to the image light from the cross dichroic prism 160, the outer shape is rectangular. It is not limited. Further, the attachment of the optical sensors OS1 to OS4 to the optical sensor attachment plate 310 is not limited to the mode shown in FIG. 2, and may be attached as shown in FIG. 7, for example.
FIG. 7 is a view showing a modification of the attachment positions of the four optical sensors to the optical sensor mounting plate. In the example of FIG. 7, the four photosensors OS1 to OS4 are attached to the photosensor mounting plate 310 so as to be located at the corners on the opening 320 side, and the four photosensors OS1 are located at such positions. The amount of misalignment can also be acquired by attaching OS4.

(2) Although the number of photosensors is four in the above-described embodiment, the number of photosensors is not limited to four, and may be three.
FIG. 8 is a diagram exemplifying attachment positions when there are three optical sensors. Three optical sensors OS1 to OS3 are attached to the optical sensor attachment plate 310 as shown in FIGS. 8A and 8B. In this way, it is possible to detect the amount of positional deviation in the horizontal and vertical directions of each of the light modulation elements 150R, 150G, and 150B.

  (3) The material of the photosensor mounting plate 310 does not necessarily have a light shielding effect, and may be a transparent material when the main purpose is to mount the photosensor. Furthermore, for example, a configuration may be employed in which the dedicated sensor mounting plate 310 is not prepared, but is directly attached to the cross dichroic prism 160, for example.

(4) The light detection unit 300 is not limited to the structure as shown in FIG. 3, and may have a structure as shown in FIG. 9, for example.
FIG. 9 is a view showing a modification of the light detection unit 300, FIG. 9 (a) is a plan view, and FIG. 9 (b) is a cross-sectional view taken along line AA in FIG. 9 (a). 9 includes a frame-shaped photosensor mounting plate 310, mirrors M1 to M4 for bending measurement light by 90 degrees, a light shielding plate 330, and photosensors OS1 to OS4. The optical sensor mounting plate 310 is the same as the optical sensor mounting plate 310 of FIG. 2, and mirrors M1 to M4 are mounted at positions along the side on the opening 320 side. The optical sensors OS1 to OS4 are attached to the optical sensor attachment plate 310 so that the reflected light from the mirrors M1 to M4 can be received. A light shielding plate 330 is attached so that light other than the light reflected by the mirrors M1 to M4 does not enter the optical sensors OS1 to OS4.
By configuring the light detection unit 300 as shown in FIG. 9, the measurement light can be more appropriately given to the optical sensors OS1 to OS4, and the light amount can be detected with high accuracy.

(5) In the above-described embodiment, as the positional deviation correction means for correcting the positional deviation of the light modulation element, the position adjustment mechanism that allows the light modulation elements 150R, 150G, and 150B to move is used. Rather than moving the modulation elements 150R, 150G, and 150B, the optical axes of the respective color lights output from the respective light modulation elements 150R, 150G, and 150B are translated in the horizontal and vertical directions (x and y directions in FIG. 2). It is also possible to use a known optical axis moving mechanism that can be used as the positional deviation correction means.
In the present invention, the positional deviation correction of the light modulation element includes not only correcting the positional deviation of the light modulation element by moving the light modulation element itself but also translating the optical axis. And This is because the displacement of the corresponding pixel between the light modulation elements is corrected as a result of correcting the displacement of the light modulation elements.

FIG. 10 is a diagram illustrating an example of the optical axis moving mechanism. FIG. 10A shows an example of an optical axis moving means that enables the optical axis to be translated by controlling the distance between the wedge-shaped transparent substrates, and FIG. 10B shows the optical axis being translated by controlling the rotation angle of the flat transparent substrate. It is an example of the optical axis moving means made possible.
As shown in FIG. 10A, the optical axis moving means by controlling the distance between the wedge-shaped transparent substrates can change the optical axis by a predetermined amount s by increasing or decreasing the distance d between the wedge-shaped transparent substrates 710a and 710b. It is a thing. Further, the optical axis moving means by controlling the distance between the flat transparent substrates can change the optical axis by a predetermined amount s by changing the rotation angle θ of the flat transparent substrate 720 as shown in FIG. 10B. Is. In any case of the wedge-shaped transparent substrate and the flat plate transparent substrate, by turning the wedge-shaped transparent substrate and the flat plate transparent substrate 90 degrees,
The moving direction of the optical axis can be moved in either the horizontal direction or the vertical direction of each of the light modulation elements 150R, 150G, 150B.

  The projector of the present invention can also be realized by providing an optical axis moving mechanism as shown in FIGS. 10A and 10B corresponding to each light modulation element. Further, by combining such an optical axis moving mechanism and the position adjusting mechanism of the light modulation element described in the above-described embodiment, it is possible to correct the positional deviation of the light modulation element.

  (6) The positions where the optical sensors OS1 to OS4 are installed are not limited to those in the above-described embodiment. For example, in a projector using a laser light source as a light source (referred to as a laser projector) or the like, output from the cross dichroic prism There is known a projector configured to form an intermediate image on a light diffusing unit provided at an image light imaging position. In the projector configured in this way, the light diffusing unit includes It is also possible to provide an optical sensor.

  FIG. 11 is a diagram schematically showing an optical system of a laser projector having a light diffusion portion. The laser projector shown in FIG. 11 includes laser light source units 810R, 810G, and 810B that generate red laser light, green laser light, and blue laser light, wavelength conversion elements 820R, 820G, and 820B, and diffractive optical elements 830R, 830G, and 830B. And optical modulation elements 840R, 840G, and 840B, a cross dichroic prism 850, an imaging optical system 860, a light diffusion unit 870, and a projection optical system 880.

  The laser projector configured as described above forms an intermediate image by forming the image light emitted from the cross dichroic prism 850 on the light diffusion unit 870 by the imaging optical system 860, and then diffuses the light in the light diffusion unit 870. The projection optical system 880 projects onto the screen SCR. In the laser projector configured as described above, the optical sensors OS1 to OS4 described in the above-described embodiments can be provided in the light diffusion unit 870, and the dedicated optical sensor mounting plate 310 can be dispensed with.

  (7) In the above-described embodiment, the case where the position of the light modulation element corresponding to RGB is adjusted in a time division manner is illustrated, but the present invention is not limited to this, and the light modulation element corresponding to each of RGB is supported. In addition to providing optical sensors, each of these optical sensors is provided with a filter that transmits the respective colors of RGB, and RGB light is applied to the corresponding light modulation elements almost simultaneously. It is also possible to detect the amount of light corresponding to the light modulation element.

  (8) In the above-described embodiment, the example in which the measurement light uses each color light of RGB from the light source has been described. However, the measurement light may be light having a wavelength exceeding the visible light range (for example, infrared light). .

  (9) In the above-described embodiment, the case where a light-transmitting light modulation element using liquid crystal is used as an example of the light modulation element. However, a reflection-type light modulation element may be used. Alternatively, a digital mirror type light modulation element may be used.

  (10) In the above-described embodiment, the absolute positional deviation of the light modulation elements is corrected. However, when only the relative positional deviation of the RGB light modulation elements is corrected, the positional deviation amount of each light modulation element. When the amount of misregistration is the same, the misalignment correction is not performed.If the misalignment amount is different, the misalignment correction is performed to the extent that the misregistration amounts match. Also good.

FIG. 3 is a plan view showing the main configuration of the optical system in the projector according to the embodiment of the invention. The figure explaining the moving direction of the light modulation element by the position adjustment mechanism of a light modulation element. FIG. 3 is a diagram illustrating a configuration example of a light detection unit 300 used in the projector according to the embodiment. The perspective view explaining the positional relationship between the cross dichroic prism 160 and the optical sensor mounting plate 300. FIG. FIG. 3 is a diagram illustrating a configuration of a light modulation element misalignment correction processing apparatus in the projector according to the embodiment. The flowchart which shows the procedure of the process performed when the position adjustment mode is set. The figure which shows the modification of the attachment position to the optical sensor attachment board of four optical sensors. The figure which shows the example of the attachment position at the time of using three optical sensors. The side view which shows the modification of an optical sensor mounting plate. The figure which shows the example of an optical axis moving means. The figure which shows typically the optical system of the laser projector which has a light-diffusion part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 100 ... Image forming unit, 110-130 ... 1st-3rd light source device, 150R, 150G, 150B ... Light modulation element, 160 ... Cross dichroic prism, 200 ... Projection optical system, DESCRIPTION OF SYMBOLS 300 ... Light detection part, 310 ... Optical sensor mounting plate, 320 ... Opening part, 330 ... Light-shielding plate, 500 ... Misalignment correction processing apparatus, 510 ... Misalignment detection part, 520... Position displacement correction control unit, 710a, 710b... Wedge-shaped transparent substrate, 720... Flat plate transparent substrate, 860... Imaging optical system, 870. ..Optical sensors, M1 to M4 ... mirrors

Claims (10)

A plurality of light modulation elements corresponding to a plurality of color components; a combination optical system that combines the color lights output from the light modulation elements of the plurality of light modulation elements and emits them as image light; and the combination optical system. A projector having a projection optical system for projecting emitted image light onto a projection surface,
When the measurement light for obtaining the positional deviation amount of each light modulation element is given to each light modulation element, the amount of the measurement light output from each light modulation element is set to each light modulation element and the light modulation element. An optical sensor for detecting at a predetermined position between the projection optical system and
A displacement detector that detects a displacement amount and a displacement direction of each of the light modulation elements based on a light amount detected by the optical sensor;
A positional deviation correction control unit that performs positional deviation correction control of each of the light modulation elements based on the positional deviation amount and the positional deviation direction;
A projector comprising: The projector according to claim 1, wherein
A plurality of the optical sensors are provided, and the plurality of optical sensors are arranged so as to be able to detect a light amount corresponding to a lateral displacement amount and a longitudinal displacement amount of each light modulation element. Projector. The projector according to claim 1 or 2,
The positional deviation amount and the positional deviation direction of each light modulation element are the amount of light detected by the optical sensor when each light modulation element is in an ideal position, and processing for obtaining the positional deviation amount of the light modulation element. And a projector that detects the difference based on a difference from the amount of light detected by the optical sensor. The projector according to any one of claims 1 to 3,
The projector is characterized in that the optical sensor is attached to an optical sensor attachment member for attaching the optical sensor. The projector according to claim 4, wherein
The projector, wherein the optical sensor mounting member is provided between the combining optical system and the projection optical system. The projector according to claim 5, wherein
The projector according to claim 1, wherein the optical sensor mounting member is a frame-shaped member having an opening that can transmit image light emitted from the combining optical system. The projector according to claim 6, wherein
The projector according to claim 1, wherein the frame member is made of a material having a light shielding effect. The projector according to any one of claims 1 to 3,
When the projector has a light diffusing unit between the projection optical system and the combining optical system and forms an intermediate image in the light diffusing unit, the light sensor is provided in the light diffusing unit. A projector characterized by that. The projector according to any one of claims 1 to 8,
Among the detection of the light quantity of the measurement light, the detection of the positional deviation amount and the positional deviation direction of each light modulation element, and the positional deviation correction control of each light modulation element, at least the detection of the light quantity of the measurement light is performed A projector characterized by performing time division for each element. A plurality of light modulation elements corresponding to a plurality of color components; a combination optical system that combines the color lights output from the light modulation elements of the plurality of light modulation elements and emits them as image light; and the combination optical system. In the projector having a projection optical system for projecting the emitted image light onto the projection surface, a position shift correction method for the light modulation element for correcting the position shift of each light modulation element,
When the measurement light for obtaining the positional deviation amount of each light modulation element is given to each light modulation element, the amount of the measurement light output from each light modulation element is set to each light modulation element and the light modulation element. Detecting by an optical sensor provided at a predetermined position between the projection optical system and
Detecting a positional deviation amount and a positional deviation direction of each light modulation element based on a light amount detected by the optical sensor;
Performing positional deviation correction control of each of the light modulation elements based on the positional deviation amount and the positional deviation direction;
A positional deviation correction method for a light modulation element in a projector, comprising: