JP7189111B2 - Color deviation correction device for light guide plate and color deviation correction method - Google Patents

Description

The present invention relates to correction of color misregistration of a light guide plate used in an image display device.

2. Description of the Related Art In image display devices such as head mounted displays (HMDs), a light guide plate is used as an optical system for propagating image light emitted from a projector (image projection unit) to the user's eyes. Here, a volume holographic multiplexed-mirror (VHM) having a light diffraction function is thin and has characteristics such as wavelength selectivity and angle selectivity, so it can selectively diffract light. By adopting this as a light guide plate for an HMD, a light guide plate that is thin and has a wide field of view (FOV) can be realized. In addition, light guide plates using VHM are being considered for use in augmented reality (AR), etc., and are required to be bright and have little RGB color shift and color unevenness.

There is Patent Document 1 as a prior art document in this technical field. Japanese Patent Laid-Open No. 2002-200000 discloses a light reflector, called a skew mirror, which has a reflection axis that does not need to be constrained by the surface normal. A skew mirror is configured to have a substantially constant reflection axis over a relatively wide range of incident angles, and a method of using a light guide plate using hologram technology and a method of manufacturing the same are disclosed.

WO2017/035283

Patent Document 1 describes a method of using and manufacturing a light guide plate using a hologram, but does not consider correction of color shift of a reproduced image emitted from the light guide plate.

SUMMARY OF THE INVENTION An object of the invention is to provide a color shift correction device and a color shift correction method for reducing color shift in a reproduced image emitted from a light guide plate.

To give an example, the present invention is a color shift correction device for a light guide plate that propagates an input image and diffracts light by a hologram to output a reproduced image, and the light guide plate is fixed to an optical system fixing device. , a light source for inputting an input image to the light guide plate is movably held by an optical system fixing device, a light receiving device for receiving a reproduced image output from the light guide plate, a light receiving device driving circuit for driving the light receiving device, A light source driving circuit for driving the light source and a control device for controlling the entire system are provided. The control device controls the light source so that the input image includes white lines, and the white lines of the reproduced image output from the light guide plate received by the light receiving device are included. is obtained for each pixel, the amount of color shift is determined from the gradation data , and based on the amount of color shift, the light source drive circuit is controlled to control the incident angle of the light source to the light guide plate or position control.

According to the present invention, it is possible to provide a light guide plate color shift correction device and a color shift correction method capable of reducing color shift in a reproduced image emitted from a light guide plate.

FIG. 10 is a cross-sectional view of the light guide plate using the VHM of the HMD in the example on the one-eye side. FIG. 10 is an image diagram for explaining color misregistration detection in the embodiment; FIG. 10 is an image diagram of color shift due to chromatic aberration in the example. 1 is a schematic configuration diagram of a color misregistration correction device in an embodiment; FIG. 3 is a hardware configuration block diagram of the color misregistration correction device in the embodiment; FIG. 6 is an overall processing flowchart of color misregistration detection and color misregistration correction in the embodiment. FIG. 7 is a detailed processing flowchart of the dashed line portion in FIG. 6; FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a light guide plate using VHM for use in an HMD (hereinafter referred to as a VHM light guide plate) in this embodiment will be described. Here, VHM is a diffractive optical element having a light diffraction function that selectively diffracts light by forming a three-dimensional (volumetric) refractive index distribution by multiplex recording holograms with different interference fringe pitches. be. A VHM light guide plate is a light guide plate that outputs a reproduced image by propagating an input image and selectively diffracting light by the VHM.

FIG. 1 is a cross-sectional view of one eye side of a VHM light guide plate of an HMD. In FIG. 1 , a group of light rays forming image light emitted from an image projection unit (not shown) enters a VHM light guide plate 200 via an incident coupler 201 . The incident coupler 201 converts the direction of the group of rays incident on the VHM light guide plate into a direction in which the light rays can propagate through the VHM light guide plate 200 by total reflection. A group of light rays that have entered the VHM light guide plate 200 are propagated by repeating total reflection, and enter an output coupler 203 composed of VHM. The output coupler 203 has a light diffraction part that diffracts some light and guides the other light like a mirror, and a large number of output light beam groups 210 are replicated in the plane and output as a reproduced image. It will be delivered to the user's eyes.

The incident coupler 201 is composed of a prism, and the VHM constituting the exit coupler 203 is composed of a reflection hologram.

Here, evaluation items for the VHM light guide plate include FOV, luminance, color unevenness (non-uniformity), color shift (RGB do not match), and the like.

Compared with other light guide plates using BSA (Beam Splitter Array), SRG (Surface Relief Grating), etc., the VHM light guide plate can expand the FOV and tends to cause color shift. Color misregistration requires an accuracy of several pixels, which is a problem for the VHM light guide plate. For improvement, it is necessary to devise a color misregistration evaluation method and an evaluation apparatus.

Here, a method for determining color misregistration of a reproduced image in this embodiment will be described. FIG. 2 is an image diagram for explaining color shift detection in this embodiment. In FIG. 2, (a) is an image to be input to the VHM light guide plate, which is an image having thin white lines in the vertical direction (Y-axis) and horizontal direction (X-axis) in an image that is entirely black. . An image input to this VHM light guide plate is emitted from the VHM light guide plate after being guided through the VHM light guide plate, and can be confirmed visually or with a camera as a reproduced image. (b) is a reproduced image emitted from the VHM light guide plate, and (c) is an enlarged view of the central portion indicated by the dotted line. In the input image shown in (a), the RGB colors of the white lines are the same, and the colors of the RGB cannot be seen even when enlarged. It can be seen that the color deviation of RGB is occurring. This color shift is seen in the vertical direction (horizontal line) and the horizontal direction (vertical line). (d) is a diagram showing the RGB gradation distribution within the dotted line in the horizontal direction (vertical line) in (c). Here, as shown in (f), if the peak center indicating the pixel position at the gradation Max and the bucket width are defined by the full width at half maximum, etc., in (d), the horizontal axis is the pixel and the vertical axis is the gradation . Therefore, the peak centers of RGB are shifted, and the bucket widths are also different. Similarly, (e) is a diagram showing the RGB gradation distribution within the dotted line in the vertical direction (horizontal line) in (c). Similarly, in (e), the peak centers of RGB are shifted, and the bucket widths are also different.

Therefore, in this embodiment, the gradation is acquired for each pixel of the reproduced image, and the following can be determined from the gradation data of each color of RGB both in the vertical direction (horizontal line) and in the horizontal direction (vertical line).
1) The shift amount of RGB colors is grasped from the shift amount of each peak center of RGB.
2) Grasp the degree of brightness of each color of RGB at the maximum gradation ( gradation Max), or the degree of blurring with the bucket width. If both the gradation Max and the bucket width are used for determination, it is possible to determine whether only one color of RGB is dark.

In addition to the color shift of the VHM light guide plate alone, color shift occurs due to chromatic aberration and incident angle shift to the incident coupler. Therefore, in the color shift evaluation of the VHM light guide plate alone, it is necessary to optimize the color shift caused by factors other than the VHM light guide plate.

FIG. 3 is an image diagram of color shift due to chromatic aberration. In FIG. 3, (a) is an input image to be input to the VHM light guide plate used for color misregistration determination. It is an image with white lines in units of minimum resolution (1 pixel, 2 pixels, etc.). (b) is an enlarged view of the reproduced image emitted from the VHM light guide plate, and is an enlarged view corresponding to the portion indicated by the dotted line in the peripheral portion of (a). , which indicates that RGB color misregistration has occurred. (c) is an enlarged view corresponding to the portion indicated by the dotted line in the central portion of (a), and shows that RGB color shifts due to chromatic aberration are less than in (b). Also, (d) is an enlarged view corresponding to the part indicated by the dotted line of the other peripheral part in (a), and as in (b), due to chromatic aberration, color shift of RGB indicating a white line occurs. showing the situation. In this way, the RGB color shift due to chromatic aberration increases in the peripheral portion of the image. Note that depending on the reproduction environment, color blurring may occur due to the mounting environment (such as defocus) of the reproduced image light receiving (camera, etc.), so care must be taken.

As described above, in the present embodiment, white vertical lines and horizontal lines are arranged in the center and the peripheral portion with the width of the minimum resolution of the incident light, and at least three or more in each of the vertical and horizontal directions are reproduced. Evaluate the color shift of This enables the following determination.
1) Horizontal RGB color misregistration can be determined by vertical lines.
2) Vertical RGB color misregistration can be determined by horizontal lines.
3) Chromatic aberration can be determined from RGB color shifts by vertical horizontal lines in the center and peripheral areas, and horizontal vertical lines.

Therefore, in this embodiment, it is possible to construct an appropriate reproduction environment by correcting the detected color shift using the color shift determination of the reproduced image.

FIG. 4 shows a schematic configuration diagram of a color misregistration correction apparatus for detecting and correcting color misregistration in this embodiment. In FIG. 4, a light receiving device 300 that receives a reproduced image emitted from the VHM light guide plate 200 and a color misregistration determination from the reproduced image from the light receiving device 300 are used to determine the optimum light source 500 for incident light to the VHM light guide plate 200. A control device 400 for outputting position information is provided, and the incident angle and position of the light source 500 are variably controlled by a drive circuit (not shown) of the light source 500 based on the position information. Note that the position of the VHM light guide plate 200 is fixed. It also has a drive circuit for controlling the position of the light receiving device 300 (not shown) for receiving the reproduced image emitted from the VHM light guide plate 200 .

Accordingly, by adjusting the incident angle and position of the light source of the incident light to the VHM light guide plate so as to correct the detected color shift, it is possible to reduce the color shift during assembly of the VHM-equipped optical system that requires the light source. Therefore, the light source can be attached to the HMD with the optimum color shift condition. In addition, by storing the optimal position information of the light source in the control device that processes the data, even if the VHM light guide plate is sold separately, the HMD can be adjusted based on the stored position information at a different timing after the sale. Assembly can also be done.

FIG. 5 is a hardware configuration block diagram of a color misregistration correction device for detecting and correcting color misregistration in this embodiment. In FIG. 5, the same components as in FIG. 4 are given the same reference numerals, and the description thereof will be omitted.

In FIG. 5, an optical system fixing device 600 serving as a base of the optical system is installed in the color misregistration correction device. A VHM light guide plate 200 including an output coupler 203 composed of recorded VHM and a light source 500 are arranged in an optical system fixing device 600, the VHM light guide plate 200 is fixed in the optical system fixing device 600, and the light source 500 is a VHM For example, it is movably held by a holding mechanism such as a mechanical arm so that the incident angle and position of light rays on the light guide plate 200 can be adjusted.

The light receiving device 300 includes an imaging device 310 that receives a reproduced image emitted from the VHM light guide plate 200 and transmits the received reproduced image to the control device 400 . Reference numeral 320 denotes a light receiving device driving circuit for driving the light receiving device 300. In order to appropriately receive the reproduced image emitted from the VHM light guide plate 200, an X-axis driving circuit 321, a Y-axis driving circuit 322, a focus It has a drive circuit 323 and receives its drive instruction from the control device 400 .

Reference numeral 510 denotes a light source driving circuit for driving the light source 500. In order to correct the detected color shift, the X It has an axis drive circuit 511 , a Y-axis drive circuit 512 , a focus drive circuit 513 and an incident angle drive circuit 514 , and receives drive instructions from the control device 400 .

Further, the control device 400 is realized by a device having a processing device (CPU), a storage device (memory), and an input/output interface (I/F), which is a general information processing device. That is, the processing of the control device 400 is executed by the CPU performing software processing on those processing programs stored in the storage device. Therefore, the internal block configuration of the control device 400 shown in FIG. 5 represents functional configuration blocks for software processing. That is, reference numeral 410 denotes an image control unit, which includes an image measurement unit 412 that measures an image for color shift detection from the reproduced image received from the light receiving device 300, and determines color shift based on the measurement result to and an image analysis unit 411 having a position information generation unit 413 for generating position information for correcting the position of the image. In addition, an adhesion control unit 420 that performs adhesion control for fixing the light source 500 on the optical system fixing device 600, and an incident light source 500 that controls the light source 500 corresponding to the input image input to the VHM light guide plate used for color misregistration determination. It has a light source controller 430 .

In addition, the image control unit 410 issues a driving instruction to the light source driving circuit 510 that drives the light source 500 so that the color shift is within a predetermined range, a driving instruction to the light receiving device driving circuit 320 that drives the light receiving device 300, and , instructs the light receiving device 300 to take an image.

Further, the control device 400 drives the light source 500 via the light source driving circuit 510 and the light receiving device 300 via the light receiving driving circuit 320 based on the position information generated by the position information generating section 413, When the color misregistration falls within a predetermined range, it is determined that the position adjustment has been completed, and the adhesion control unit 420 outputs an adhesion instruction. A bonding device 440 bonds and fixes the light source 500 onto the optical system fixing device 600 with a UV curing resin by UV irradiation or the like according to the bonding instruction.

FIG. 6 is a flow chart of overall processing of color shift detection and color shift correction in this embodiment. In FIG. 6, first, in step S10, the optical system fixing device 600 is installed in the color shift correction device, the VHM light guide plate 200 and the light source 500 are arranged in the optical system fixing device 600, and the VHM light guide plate 200 is attached to the optical system fixing device. 600 and the light source 500 is movably held.

Next, in S21, incident light source information for controlling the light source 500 is set in correspondence with the input image to be input to the VHM light guide plate used for color misregistration determination, and is input to the light source 500. FIG. As a result, an input image used for color misregistration determination is input to the VHM light guide plate 200 from the light source 500, and a reproduced image emitted from the VHM light guide plate 200 is received by the light receiving device 300 and captured by the imaging device 310. (S22). Then, the image measurement unit 412 measures the image of the white line from the captured reproduced image (S23). Then, in S24, the amount of color misregistration is determined from the measurement result of the image, and image analysis is performed to determine whether the amount of color misregistration is within a desired range. Then, if the amount of color misregistration is not within the desired range, in S25, the correction device performs position correction processing, returns to S21, and repeats the processes from S21 to S24 until the amount of color misregistration is within the desired range in S24. Repeat the process.

When the amount of color misregistration falls within the desired range, the optimum position information of the light source is stored in the storage device in S50, and the propriety of adhesion for fixing the light source 500 on the optical system fixing device 600 is determined in S60. If the light source 500 can be adhered, the adhesion device 440 adheres and fixes the light source 500 onto the optical system fixing device 600 with UV curable resin, for example, by UV irradiation according to the adhesion instruction from the adhesion control unit 420 in S70.

FIG. 7 is a detailed processing flowchart of the dashed line portion S20 in FIG. In FIG. 7, after the white line image is measured by image measurement in S23, the desired number of white lines in the reproduced image emitted from the VHM light guide plate 200 in S31 (in this embodiment, as shown in FIG. 3 vertical and horizontal lines). If the desired number of lines is not present (if any of the vertical and horizontal lines are not present), the process advances to S32 to determine whether or not there are the desired number (three) of vertical lines in the horizontal direction. If there are the desired number (3) of vertical lines, it means that there are not the desired number (3) of horizontal lines in the vertical direction. If there is, proceed to S34, drive the light source 500 along the Y-axis in the vertical direction, control the position of the light source so that the desired number (three) of vertical horizontal lines are included in the reproduced image, and return to S21. If the light receiving device has not been driven in S33, the process advances to S35, in which the light receiving device 300 is driven along the vertical Y-axis, and a desired number (three) of vertical horizontal lines are entered in the captured image received by the light receiving device 300. The position of the light receiving device is controlled as in the above, and the process returns to S21. If the desired number (3) of vertical lines is not found in S32, it means that the desired number (3) of vertical lines in the horizontal direction is not present. If it has already been driven, the process proceeds to S37, the light source 500 is driven along the horizontal X-axis, the position of the light source is controlled so that the desired number (three) of horizontal vertical lines are included in the reproduced image, and the process proceeds to S21. return. If the light receiving device has not been driven in S36, the process advances to S38 to drive the light receiving device 300 along the X axis in the horizontal direction so that the desired number (3) of vertical lines in the horizontal direction appears in the captured image received by the light receiving device 300. The position of the light receiving device is controlled so as to enter, and the process returns to S21. The above processing from S31 to S38 is repeated until the number of white lines in the reproduced image reaches the desired number in S31. The above is the initial setting of the positions of the light receiving device 300 and the light source 500 so that the minimum desired number of white lines (in this embodiment, 3 in the vertical and horizontal directions) is included in the reproduced image used for color misregistration determination.

Next, if the number of white lines in the reproduced image is the desired number in S31, the process proceeds to S39 to check the focus shift. That is, it is determined whether the bucket width explained in FIG. 2 is equal to or less than a certain width. If it is determined that the bucket width is not equal to or less than the predetermined width and there is a focus shift, the process proceeds to S40 to determine whether the light receiving device has been driven. If the light receiving device has already been driven, the process proceeds to S41, performs focus drive of the light source 500, performs focus control of the input image to be input to the VHM light guide plate, and returns to S21. On the other hand, if the light receiving device has not been driven, the process proceeds to S42, focus drive of the light receiving device 300 is performed, focus control of the captured image received by the light receiving device 300 is performed, and the process returns to S21. The above processing from S39 to S42 is repeated until it is determined in S39 that there is no defocus. The above is the processing for adjusting the color shift caused by the focus shift.

Next, if it is determined in S39 that there is no defocus, the process proceeds to S43 to confirm whether the RGB difference is within a certain range. That is, the shift amounts of the RGB colors are determined based on the shift amounts of the peak centers of the respective RGB lines on each of the vertical line and the horizontal line described with reference to FIG. If the RGB color deviation amount is not equal to or less than the predetermined width, the process advances to S44 to determine whether the horizontal vertical line RGB color deviation amount is equal to or less than the predetermined width. If the amount of RGB color shift of the horizontal vertical line is less than or equal to the predetermined width, it means that the amount of RGB color shift of the vertical horizontal line is not less than or equal to the predetermined width. , it is determined whether the light receiving device has been driven, and if the light receiving device has been driven, the process proceeds to S34, where the light source 500 is driven along the Y-axis in the vertical direction to reduce the shift amount of the RGB colors of the horizontal horizontal lines in the vertical direction. Then, control the position of the light source so as to cause the light source to return to S21. If the light receiving device has not been driven in S33, the process advances to S35 to drive the light receiving device 300 along the Y axis in the vertical direction. The position of the light receiving device is controlled so as to reduce it, and the process returns to S21.

If the amount of RGB color shift of the horizontal vertical line is not equal to or less than the predetermined width, it means that the amount of RGB color shift of the horizontal vertical line is large. If the incident angle has already been driven, the process proceeds to S36; otherwise, the process proceeds to S46, performs the incident angle drive of the light source, and returns to S21. Here, the intention of the processing in S45 and S46 is that the horizontal vertical line changes depending on the incident angle of the light source. Adjustment is made so as to reduce the deviation amount of the RGB colors of the line.

After proceeding to S36 when the incident angle has been driven in S45, it is determined whether or not the light receiving device has been driven as described above. The position of the light source is controlled so as to drive along the X-axis and reduce the amount of deviation of the RGB colors of the vertical lines in the horizontal direction, and the process returns to S21. If the light receiving device has not been driven in S36, the process advances to S38 to drive the light receiving device 300 along the X-axis in the horizontal direction, and calculate the amount of RGB color deviation of the horizontal vertical lines in the captured image received by the light receiving device 300. is reduced, and the process returns to S21. The above processing from S43 to S46 is repeated until the RGB difference becomes equal to or less than a certain width in S43. The above is the processing for adjusting the color misregistration of RGB.

As described above, according to this embodiment, it is possible to provide a light guide plate color shift correction device and a color shift correction method capable of reducing color shift in a reproduced image emitted from a VHM light guide plate.

Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the described configurations.

200: VHM light guide plate, 201: Incident coupler, 203: Output coupler, 210: Output light beam group, 300: Light receiving device, 310: Imaging device, 320: Light receiving device drive circuit, 321, 511: X-axis drive circuit, 322, 512: Y-axis drive circuit, 323, 513: focus drive circuit, 400: control device, 410: image control unit, 411: image analysis unit, 412: image measurement unit, 413: position information generation unit, 420: adhesion control unit , 430: incident light source controller, 440: bonding device, 500: light source, 510: light source driving circuit, 514: incident angle driving circuit, 600: optical system fixing device.

Claims (15)

A color shift correction device for a light guide plate that outputs a reproduced image by propagating an input image and diffracting light with a hologram,
The light guide plate is fixed to an optical system fixing device, and a light source for inputting the input image to the light guide plate is movably held by the optical system fixing device,
a light receiving device for receiving a reproduced image output from the light guide plate;
a light receiving device driving circuit for driving the light receiving device;
a light source driving circuit for driving the light source;
Equipped with a control device that controls the whole
The control device controls the light source so that the input image includes a white line, and outputs RGB color gradation data that constitutes the white line of the reproduced image output from the light guide plate received by the light receiving device for each pixel. and determining the amount of color shift from the gradation data, and based on the amount of color shift, controlling the light source drive circuit to control the incident angle or position of the light source on the light guide plate. A device for correcting color misregistration of a light guide plate. The color misregistration correction device for a light guide plate according to claim 1,
The control device controls that the input image input from the light source to the light guide plate is a white vertical line and a white horizontal line arranged at the center and the periphery of the input image, and at least three lines are arranged in each of the vertical and horizontal directions. A device for correcting color deviation of a light guide plate, wherein the light source is controlled so as to produce an image having white lines. The color misregistration correction device for a light guide plate according to claim 2,
A color deviation correction device for a light guide plate, wherein the control device determines the amount of color deviation based on the amount of deviation between peak centers of the respective RGB gradation data. The color misregistration correction device for a light guide plate according to claim 2,
The color deviation correction device for a light guide plate, wherein the control device determines the amount of color deviation based on the bucket width of each of the RGB gradation data. The device for correcting color misregistration for a light guide plate according to claim 3,
The control device controls the light source or the light receiving device to reproduce the input image or the reproduced image by the light receiving device driving circuit or the light source driving circuit when the amount of RGB color shift in the vertical direction indicated by the horizontal line is greater than or equal to a predetermined range. driven to move longitudinally,
If the amount of RGB color shift in the horizontal direction of the vertical line is greater than or equal to a predetermined range, the light source drive circuit drives the incident angle of the light source to be variable if the incident angle of the light source to the light guide plate has not been driven. and when the incident angle has already been driven, the light source or the light receiving device is driven by the light receiving device driving circuit or the light source driving circuit so as to move in the lateral direction of the input image or the reproduced image. A device for correcting color misregistration for a light guide plate. The color misregistration correction device for a light guide plate according to claim 4,
When the bucket width of the gradation data is equal to or greater than a predetermined width, the control device drives the light source or the light receiving device to move in the focus direction by the light receiving device drive circuit or the light source drive circuit. A device for correcting color misregistration for a light guide plate. The color misregistration correction device for a light guide plate according to claim 2,
When the received reproduced image does not have the desired number of horizontal lines in the vertical direction, the control device controls the light source or the light receiving device to vertically shift the input image or the reproduced image by the light receiving device driving circuit or the light source driving circuit. drive to move in the direction of
When the received reproduced image does not have a desired number of vertical lines in the horizontal direction, the light source or the light receiving device is moved in the horizontal direction of the input image or the reproduced image by the light receiving device driving circuit or the light source driving circuit. A color misregistration correction device for a light guide plate, characterized in that it is driven as follows. The color misregistration correction device for a light guide plate according to claim 1,
a bonding device for bonding the light source to the optical system fixing device;
When the control device determines that the color shift is within a predetermined range by controlling the incident angle or position of the light source on the light guide plate, the control device determines that the position adjustment is completed, and outputs a bonding instruction to the bonding device. 2. A color misregistration correcting device for a light guide plate, wherein said bonding device bonds said light source to said optical system fixing device. A color shift correction method for a light guide plate that outputs a reproduced image by propagating an input image and diffracting light with a hologram,
the input image is input to the light guide plate by light emitted from a light source;
the input image includes a white line;
receiving a reproduced image output from the light guide plate;
Acquiring grayscale data for each of the RGB colors forming the white line of the received reproduced image for each pixel,
determining the amount of color shift from the gradation data;
A method for correcting color shift in a light guide plate, comprising: controlling an incident angle or position of the light source to the light guide plate based on the amount of color shift. A method for correcting color misregistration for a light guide plate according to claim 9,
The light guide plate, wherein the input image is an image having white vertical lines and horizontal lines arranged in the center and the periphery of the input image, and having at least three white lines in each of the vertical and horizontal directions. color shift correction method. A method for correcting color misregistration for a light guide plate according to claim 10,
A method of correcting color shift for a light guide plate, wherein the determination of the amount of color shift is based on the amount of shift between peak centers of the RGB tone data. A method for correcting color misregistration for a light guide plate according to claim 10,
A method of correcting color shift for a light guide plate, wherein the determination of the amount of color shift is based on bucket widths of the grayscale data for each of the RGB. The method for correcting color misregistration for a light guide plate according to claim 11,
driving the light source or the light receiving device for receiving the reproduced image so as to move the input image or the reproduced image in the vertical direction when the RGB color shift amount in the vertical direction of the horizontal line is greater than or equal to a predetermined range;
If the amount of RGB color shift in the horizontal direction of the vertical line is greater than or equal to a predetermined range, driving is performed so that the incident angle of the light source to the light guide plate is variable if the incident angle of the light source to the light guide plate has not been driven; is already driven, driving the light source or the light receiving device for receiving the reproduced image so as to move in the horizontal direction of the input image or the reproduced image. A method for correcting color shift of a light guide plate according to claim 12,
A color misregistration correcting method for a light guide plate, wherein when the bucket width of the gradation data is equal to or larger than a predetermined width, the light source or the light receiving device for receiving the reproduced image is driven to move in the focus direction. A method for correcting color misregistration for a light guide plate according to claim 10,
driving the light source or the light-receiving device for receiving the reproduced image so as to move in the vertical direction of the input image or the reproduced image when the number of horizontal lines in the vertical direction of the received reproduced image is less than the desired number;
driving the light source or the light-receiving device for receiving the reproduced image so as to move the input image or the reproduced image in the horizontal direction when the number of vertical lines in the horizontal direction of the received reproduced image is not a desired number; A method for correcting color shift of a light guide plate.

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