JP6973988B2 - Image display device and image display method - Google Patents

Description

The present invention relates to an image display device and an image display method for improving the contrast ratio by using two LCD panels.

In the conventional image display device using a single LCD panel, the input image is corrected by a polygonal line gamma with a panel driver to realize the linearity characteristic of the gradation visually.

However, in reality, since the brightness is expressed by transmitting the illumination of the backlight through the liquid crystal panel, the gradation characteristics in the black region are particularly poor, and the brightness is observed in a brighter direction than the ideal brightness. The so-called black floating phenomenon occurs.

This phenomenon occurs because the LCD panel is not completely shielded from light when displaying a dark area on the LCD panel, and the illumination light of the backlight leaks. A contrast ratio of about 10000: 1 is realized in the conventional CRT, and a contrast ratio of about 10000: 1 is realized in the organic EL panel. However, due to this phenomenon, a contrast ratio of only about 1500: 1 can be realized in a conventional image display device using a single LCD panel.

Therefore, in order to improve the contrast ratio of such a single LCD image display device, an image display device using two LCDs has been proposed (see, for example, Patent Documents 1 and 2). Each image display device has a configuration in which two LCDs are used, the amount of transmission of the backlight is adjusted by the LCD on the rear side, and RGB display is performed on the LCD on the front side in order to improve the contrast ratio.

Japanese Unexamined Patent Publication No. 5-88197 International Publication No. 2007/108183

However, the prior art has the following problems.
As described above, the image display device using a single LCD panel has a problem that the contrast ratio can be realized only about 1500: 1. Further, there is a big problem that faithful reproduction of an image cannot be realized with one LCD due to deterioration of color reproducibility in a dark image and deterioration of black quality.

On the other hand, an image display device using two LCD panels as in Patent Documents 1 and 2 has an effect of improving contrast and preventing blackening. However, such an image display device using two LCD panels has a problem that a positional shift occurs in the process of bonding the two LCD panels. Therefore, this problem will be described below with reference to the drawings.

FIG. 10 is a diagram for explaining a general image display device using two LCD panels. In FIG. 10, the LCD panel on the backlight side on the rear side is referred to as LV panel 2 (Light Valve Panel), and the LCD panel on the front side, which is closer to the person viewing the image, is referred to as RGB panel 1.

As shown in FIG. 10, the RGB panel 1 and the LV panel 2 are bonded to each other via the light diffusion layer 3. Here, the RGB panel 1 is composed of R, G, and B sub-pixels. On the other hand, in the LV panel 2, the sub-pixels of R, G, and B are collectively regarded as one pixel. That is, one pixel of the LV panel 2 is common to one pixel of the sub-pixels of the RGB panel 1, and there is a 1: 1 correspondence.

Then, by pasting the RGB panel 1 and the LV panel 2 back and forth and illuminating the backlight from the LV panel 2 side, the contrast ratio is improved by the effect of multiplying the light transmittances of the rear and front panels. ing.

However, in the bonding of the RGB panel 1 and the LV panel 2, if the relative positional deviation between the two panels occurs, there arises a problem that the compositely displayed image (composite image) is blurred. FIG. 11 is a diagram for explaining a misalignment problem in a conventional image display device. As shown in FIG. 11, as a result of bonding the RGB panel 1 and the LV panel 2 in a state including an alignment error, blurring occurs in the composite image for which the contrast ratio is to be improved.

A direct bonding process is required to bond the two LCD panels together. However, in this manufacturing process, it is difficult to guarantee the physical position accuracy, and there is a possibility that the image may be blurred to some extent. Further, in order to keep the alignment error within the permissible value and perform the bonding, a very expensive manufacturing device is required.

The present invention has been made to solve the above-mentioned problems, and when two LCD panels are used to improve the contrast ratio, the deterioration of the composite image due to the misalignment of the bonded images is caused. It is an object of the present invention to obtain an image display device and an image display method capable of suppressing the decrease in yield, compensating for a decrease in yield, and reducing costs.

The image display device according to the present invention is configured by stacking two LCD panels on the front side and an LCD panel on the rear side, and displays an image by transmitting the backlight light in the order of the LCD panel on the rear side and the LCD panel on the front side. An RGB controller that generates an RGB image signal after performing the first processing for displaying the input RGB image signal on the front LCD panel, and an input RGB. By the process of bonding the LV controller that generates the first gray image signal after the second processing for displaying the image signal on the rear side LCD panel, and the front side LCD panel and the rear side LCD panel. As the amount of misalignment, the amount of shift corresponding to the amount of horizontal and vertical displacement of the rear LCD panel with respect to the front LCD panel, and the amount of rotation corresponding to the amount of displacement of the rear LCD panel with respect to the front LCD panel in the rotation direction. It has a storage unit stored in advance, and the display position coordinate correction according to the shift amount and the rotation amount is performed on the first gray image signal generated by the LV controller to generate the second gray image signal, and the second gray is generated. It is provided with a shift / rotation correction unit that compensates for the amount of misalignment caused in the bonding process by supplying an image signal to the rear LCD panel.

Further, the image display method according to the present invention is configured by stacking two front-side LCD panels and two rear-side LCD panels, and the backlight light is transmitted through the rear-side LCD panel and the front-side LCD panel in this order. This is an image display method for displaying an image, in which a camera captures a plurality of marker positions on the front side LCD panel and a plurality of marker positions on the rear side LCD panel after the step of bonding the front side LCD panel and the rear side LCD panel. From the first step, the multiple marker positions of the front LCD panel acquired in the first step, and the multiple marker positions of the rear LCD panel, the amount of misalignment due to the bonding process is the rear LCD with respect to the front LCD panel. The second step of calculating the shift amount corresponding to the horizontal and vertical displacement amount of the panel and the rotation amount corresponding to the rotation direction deviation amount of the rear side LCD panel with respect to the front side LCD panel and storing them in the storage unit. The third step of generating an RGB image signal after performing the first processing for displaying the input RGB image signal on the front side LCD panel, and the rear side with respect to the input RGB image signal. The fourth step of generating the first gray image signal after the second processing for displaying on the LCD panel and the first gray image signal generated in the fourth step are stored in the storage unit. A second gray image signal is generated by correcting the display position coordinates according to the shift amount and the rotation amount, and the second gray image signal is supplied to the rear LCD panel to compensate for the amount of misalignment generated in the bonding process. It has 5 steps.

According to the present invention, there is a configuration in which the positional deviation generated in the process of bonding two LCD panels is corrected at the display stage by signal processing on the LV panel side. As a result, when two LCD panels are used to improve the contrast ratio, the deterioration of the composite image due to the misalignment of the bonded images can be suppressed, the yield decrease can be compensated, and the cost can be reduced. A display device and an image display method can be obtained.

It is a signal processing block diagram of an image display device configured by sticking two LCD panels together. It is a figure which shows the whole structure of the image display device in Embodiment 1 of this invention. It is a flowchart of the arithmetic processing executed by the PC in Embodiment 1 of this invention. It is a figure which showed the positional relationship of 4 points of a marker detected by the marker detection part in Embodiment 1 of this invention. It is a figure for demonstrating the calculation process of the shift amount and the rotation amount executed by the shift amount / rotation amount calculation unit in Embodiment 1 of this invention. It is a figure which showed the internal structure of the shift / rotation correction part in Embodiment 1 of this invention. It is a figure which showed 5 images by the 1st simulation result in Embodiment 1 of this invention. It is a figure which showed 5 images by the 2nd simulation result in Embodiment 1 of this invention. It is a figure which showed two images by the 3rd simulation result in Embodiment 1 of this invention. It is a figure for demonstrating a general image display apparatus using two LCD panels. It is a figure for demonstrating the position shift problem in the conventional image display apparatus.

Hereinafter, preferred embodiments of the image display device and the image display method of the present invention will be described with reference to the drawings.

In the present invention, two LCD panels are attached back and forth, and the backlight is illuminated from the back side thereof, so that the contrast ratio is improved by the effect of multiplying the light transmission rates of the back side and the front side panels. The display device and the image processing method are technically characterized by having a configuration in which the positional deviation generated in the step of bonding two LCD panels is corrected at the display stage by signal processing on the LV panel side.

Embodiment 1.
First, the overall configuration of a general liquid crystal display device in which two LCD panels are bonded together will be described. FIG. 1 is a signal processing block diagram of an image display device configured by laminating two LCD panels. The image display device shown in FIG. 1 includes an RGB controller 10 and an LV controller 20.

Here, the RGB controller 10 includes a bit expansion circuit 11, a delay circuit 12, a gradation conversion circuit 13, and a color balance controller 14, and the output from the color balance controller 14 is supplied to the RGB panel 1.

Further, the LV controller 20 includes a gray converter 21, a gradation conversion circuit 22, an edge hold circuit 23, and a low-pass filter 24, and the output from the low-pass filter 24 is supplied to the LV panel 2.

Next, the outline of signal processing by the RGB controller 10 and the LV controller 20 will be described.

As an example, the bit expansion circuit 11 performs bit expansion processing to 12 bits for an input RGB 10-bit image. This bit expansion process expands the bit length with high accuracy in advance so as not to reduce the bit accuracy in the subsequent processing. The bit expansion circuit 11 transmits the RGB image after the bit expansion to each of the delay circuit 12 and the gray converter 21.

In the configuration shown in FIG. 1, the bit expansion circuit 11 is provided inside the RGB controller 10, but the bit expansion circuit 11 is provided outside the RGB controller 10, and the RGB image after the bit expansion is referred to as the RGB controller 10. It is also possible to supply the LV controller 20.

Further, in order not to reduce the bit accuracy in the subsequent processing, it is possible to adopt a configuration in which the bit expansion circuit 11 is eliminated when the processing such as expanding the bit length with high accuracy is not required in advance.

The delay circuit 12 in the RGB controller 10 receives the RGB image after bit expansion from the bit expansion circuit 11, and applies an appropriate delay to the received RGB image after bit expansion. This "appropriate delay" is for compensating for the delay in processing by the gray converter 21, the edge hold circuit 23, and the low-pass filter 24 in the LV controller 20.

Next, the gradation conversion circuit 13 in the RGB controller 10 performs gradation conversion using a LUT (look-up table) for each color after the delay.

On the other hand, the gray converter 21 in the LV controller 20 receives the RGB image after bit expansion from the bit expansion circuit 11, and for the received RGB image after bit expansion, three values of RGB are used for each pixel. Converts to a gray image with the maximum value in.

Usually, for conversion to grayscale, luminance is often obtained by performing color matrix conversion using a multiplier and an adder. The gray converter 21 in the first embodiment detects the maximum value of R, G, and B in each pixel so that the color balance controller 14 in the RGB controller 10 can easily correct the RGB color balance. However, by outputting this as a representative value, the hardware is also simplified.

Of course, it goes without saying that the color balance correction process can be executed without any problem even when the normal matrix conversion is adopted.

Next, the gradation conversion circuit 22 in the LV controller 20 performs gradation conversion on the gray image using the LUT. Next, the edge hold circuit 23 in the LV controller 20 corrects the viewing angle of the gray image after gradation conversion, and generates a gray image (B / W image).

Further, the low-pass filter 24 in the LV controller 20 performs a process of smoothing the edge portion by performing a filter process on the gray image after the viewing angle correction by the edge hold circuit 23.

The gray image processed by the low-pass filter 24 is displayed on the LV panel 2 and transmitted to the color balance controller 14 in the RGB controller 10. Then, the color balance controller 14 in the RGB controller 10 corrects the color balance based on the signal after the gradation conversion by the gradation conversion circuit 13 and the gray image after the processing by the low-pass filter 24, and after the correction, the color balance controller 14 corrects the color balance. The RGB image is displayed on the RGB panel 1.

Next, an image provided with a configuration for realizing the technical feature of the present invention, "the positional deviation generated in the process of pasting two LCD panels is corrected at the display stage by signal processing on the LV panel side". The display device will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing the overall configuration of the image display device according to the first embodiment of the present invention. The image processing apparatus according to the first embodiment shown in FIG. 2 further includes a shift / rotation correction unit 30 provided in the subsequent stage of the LV controller 20 with respect to the configuration of FIG. 1 above. The shift / rotation correction unit 30 has a signal processing function for correcting the positional deviation generated in the process of bonding the RGB panel 1 and the LV panel 2 at the display stage on the LV panel 2 side.

In order to realize this signal processing function by the shift / rotation correction unit 30, it is necessary to quantitatively calculate the amount of misalignment after the RGB panel 1 and the LV panel 2 are bonded together as the shift amount and the rotation amount. be. For this purpose, in the configuration of FIG. 2, a PC (personal computer) 40 and a camera 50 are used.

In the panel manufacturing process, the camera 50 captures the position of the marker 4 provided for alignment on each panel after the two LCD panels are bonded together. Then, the image captured by the camera 50 is taken into the PC 40, and the shift amount and the rotation amount are calculated.

The PC 40 has a marker detection unit 41 having an arithmetic processing mechanism for calculating the position of the marker 4 based on the input image, and an arithmetic processing mechanism for calculating the shift amount and the rotation amount based on the calculated position of the marker 4. It is configured to include a shift amount / rotation amount calculation unit 42.

Next, the specific arithmetic processing by the marker detection unit 41 and the shift amount / rotation amount calculation unit 42 will be described in detail with reference to the flowchart of FIG. 3 and the explanatory diagrams of FIGS. 4 and 5. FIG. 3 is a flowchart of arithmetic processing executed by the PC 40 in the first embodiment of the present invention.

First, in step S301, the marker detection unit 41 in the PC 40 captures the image captured by the camera 50. This image contains two or more markers 4 on each panel after the RGB panel 1 and the LV panel 2 are bonded together.

In the following, in order to simplify the explanation, the positions of the two marker 4s on the RGB panel 1 are P0 and P1, and the positions of the two marker 4s on the LV panel 2 are P2 and P3. The case of calculating the shift amount and the rotation amount will be described. When the four markers are pasted together without any positional deviation, the positions of P0 and P2 are the same, and the positions of P1 and P3 are the same.

Next, in step S302, the marker detection unit 41 detects the position coordinates of each marker 4 on the XY plane of each panel as the following values.
P0 (x0, y0)
P1 (x1, y1)
P2 (x2, y2)
P3 (x3, y3)

In the following, in order to simplify the explanation, P0 is the coordinate origin (0,0), and the remaining P1, P2, and P3 are the positions when P0 is the coordinate origin. FIG. 4 is a diagram showing the positional relationship of the four markers detected by the marker detection unit 41 in the first embodiment of the present invention. The positional relationship of P1 to P3 when P0 is the origin is shown, and the marker detection unit 41 detects the position coordinates of four points as shown in FIG.

Next, in step S303, the shift amount / rotation amount calculation unit 42 calculates the shift amount and the rotation amount for matching P2 with P0 and P3 with P1. FIG. 5 is a diagram for explaining the calculation process of the shift amount and the rotation amount executed by the shift amount / rotation amount calculation unit 42 in the first embodiment of the present invention.

Assuming that the coordinates after moving P2 (x2, y2) to the position corresponding to P0 (0, 0) are P2'(x2', y2'), the shift amount at that time is as clear from FIG. In addition, it is calculated by (-x2, -y2).

Further, assuming that the coordinates after shifting P3 (x3, y3) by the same amount as (-x2, -y2) are P3'(x3', y3'), the coordinates of P3'are
x3'= x3-x2
y3'= y3-y2
It is calculated by.

That is, the shift amount / rotation amount calculation unit 42 shifts the shift amount based on the coordinate value of P2: (-x2, -y2).
Can be calculated as.

Next, the angle θ between the line segment P0-P1 and the line segment P2'-P3' has the relationship of the following equation (1) from the equation of the inner product.

Therefore, the rotation amount θ is calculated by the following equation (2).

That is, the shift amount / rotation amount calculation unit 42 can calculate the rotation amount as the above equation (2) based on the coordinate values of P1, P2, and P3.

Then, in step S304, the shift amount / rotation amount calculation unit 42 outputs the calculated shift amount and rotation amount, and the shift / rotation correction unit 30 outputs the shift amount and rotation amount calculated by the shift amount / rotation amount calculation unit 42. By using the amount of rotation as a parameter and performing signal processing on the LV panel side, it is possible to compensate for the misalignment that occurs in the process of bonding the two LCD panels together.

Next, the detailed configuration of the shift / rotation correction unit 30 will be described with reference to the drawings. FIG. 6 is a diagram showing an internal configuration of the shift / rotation correction unit 30 according to the first embodiment of the present invention. The shift / rotation correction unit 30 shown in FIG. 6 includes a parameter memory 31, an address controller 32, an input memory 33, and a rotating coordinate conversion unit 34.

The parameter memory 31 is a memory that stores the shift amount and the rotation amount calculated by the PC 40. Here, in the following description, the shift amount set in the parameter memory 31 is (−a, −b), and the rotation amount is θ.

On the other hand, the input memory 33 is a memory for storing image data output from the LV controller 20. Then, the address controller 32 shifts the image data stored in the input memory 33 according to the shift amounts (−a, −b) stored in the parameter memory 31. This correction of the shift amount corresponds to the shift correction so that P2 and P3 match P2'and P3', respectively, as described with reference to FIG.

Further, the rotating coordinate conversion unit 34 corrects the rotation amount for the image data after the shift amount is corrected according to the rotation amount θ stored in the parameter memory 31. This correction of the amount of rotation corresponds to the rotation correction of P3'so as to match P1 as described with reference to FIG.

Then, the rotating coordinate conversion unit 34 supplies the image data after the rotation correction to the LV panel 2. As a result, by signal processing of the image data displayed on the LV panel 2 side, it is possible to eliminate the positional deviation between the image data displayed on the RGB panel 1 and the image data displayed on the LV panel 2 side, and the quality is high. It is possible to display various composite images.

In the configuration shown in FIG. 6, the shift amount is corrected (translation) and the rotation amount is corrected (rotational movement) separately, but the coordinate values of the image before the correction are set to (x, y). Assuming that the coordinate values of the image after correcting the shift amount θ and the rotation amount (-a, -b) are (x', y'), the shift amount and the rotation amount can be obtained by performing the rotation coordinate conversion of the following equation. It can also be corrected at the same time.

Next, the simulation results using the sample images will be described. FIG. 7 is a diagram showing five images obtained from the first simulation result in the first embodiment of the present invention. Specifically, in this first simulation, the improvement effect of the composite image was verified when the LV panel 2 was bonded to the RGB panel 1 in a state where the LV panel 2 was shifted by 10 pixels in each of the horizontal and vertical directions. It is a thing.

Each of the five images corresponds to an image having the following contents.
Image (7-1): Original image image (7-2) input to the display device according to the first embodiment: Image for RBG output from the RGB controller 10 Image (7-3): From the LV controller 20. Output image for LV Image (7-4): A composite image obtained from the image (7-2) and the image (7-3) without correction by the shift / rotation correction unit 30, and the original image. Image (7-5): After being corrected by the shift / rotation correction unit 30, a composite image obtained from the image (7-2) and the image (7-3) is compared with the original image.

From the result of this first simulation, it can be seen that the composite image is improved by shift-correcting the image data displayed on the LV panel 2 side in consideration of the deviation of 10 pixels as the shift amount.

Next, FIG. 8 is a diagram showing five images based on the second simulation result in the first embodiment of the present invention. Specifically, in this second simulation, the improvement effect of the composite image is verified when the LV panel 2 is attached to the RGB panel 1 in a state of being rotated by 10 ° in the rotation direction.

Each of the five images corresponds to an image having the following contents.
Image (8-1): Original image image (8-2) input to the display device according to the first embodiment: Image for RBG output from the RGB controller 10 Image (8-3): From the LV controller 20. Output image for LV Image (8-4): A composite image obtained from an image (8-2) and an image (8-3) without correction by the shift / rotation correction unit 30, and an original image. Image (8-5): After being corrected by the shift / rotation correction unit 30, a composite image obtained from the image (8-2) and the image (8-3) is compared with the original image.

From the result of this second simulation, it can be seen that the composite image is improved by correcting the rotation of the image data displayed on the LV panel 2 side in consideration of the deviation of 10 ° as the rotation amount.

Next, FIG. 9 is a diagram showing two images based on the third simulation result in the first embodiment of the present invention. Specifically, in this third simulation, the LV panel 2 is attached to the RGB panel 1 in a state where the LV panel 2 is shifted by 10 pixels in each of the horizontal and vertical directions and is rotated by 10 ° in the rotation direction. This is a verification of the improvement effect of the composite image in the case.

Each of the two images corresponds to an image having the following contents.
Image (8-4): Composite image obtained from RGB image and LV image without correction by shift / rotation correction unit 30 Image (8-5): After correction by shift / rotation correction unit 30, RGB Composite image obtained from image and LV image

From the result of this third simulation, the image data to be displayed on the LV panel 2 side is shifted / rotated by considering the deviation of 10 pixels as the shift amount and the deviation of 10 ° as the rotation amount. By doing so, it can be seen that the composite image is improved.

When shift correction and rotation correction are applied to the LV image, the image at the edge of the screen of the RGB panel 1 is the corrected image of the LV panel 2 according to the shift amount and the magnitude of the rotation amount. There is a risk that an area that does not overlap with will appear. Therefore, in consideration of the maximum shift amount and rotation amount that can occur in the manufacturing process, it is conceivable to increase the size of the LV panel by a plurality of pixels in the vertical and horizontal directions.

In this way, by securing the display area of the LV panel 2 several pixels larger in the vertical and horizontal directions than the display area of the RGB panel 1, even after the image data to be displayed on the LV panel 2 side is shifted / rotated corrected, RGB is displayed. A composite image can be obtained in the entire area of the image.

Further, in the first embodiment described above, a case where the shift amount and the rotation amount are obtained from the marker positions of two points per panel has been described. However, according to the present invention, it is possible to obtain the shift amount and the rotation amount from the marker positions of three or more points for each panel, and in this case, the correction accuracy can be further improved.

As described above, according to the first embodiment, after manufacturing two LCD panels, an LV image obtained by obtaining the amount of misalignment for bonding and performing shift / rotation correction so as to cancel the amount of misalignment is obtained. It has a configuration to be displayed on the LV panel side. As a result, when two LCD panels are used to improve the contrast ratio, deterioration of the composite image due to the misalignment of the bonded images can be suppressed, and the decrease in yield can be compensated and the cost can be reduced.

Furthermore, by manufacturing the LV panel so that the number of pixels of the LV panel is larger than the number of pixels of the RGB panel by several pixels in the vertical and horizontal directions, the position of the bonding is displaced over the entire display area of the RGB panel. It is possible to suppress the deterioration of the composite image caused by it.

Further, although not described in the first embodiment, when implementing translation of one pixel or less, it is conceivable to use interpolation calculation by a filter.

1 RGB panel, 2 LV panel, 3 light diffusion layer, 4 marker, 10 RGB controller, 11-bit expansion circuit, 12 delay circuit, 13 gradation conversion circuit, 14 color balance controller, 20 LV controller, 21 gray converter, 22nd floor Adjustment conversion circuit, 23 edge hold circuit, 24 low pass filter, 30 shift / rotation correction unit, 31 parameter memory, 32 address controller, 33 input memory, 34 rotation coordinate conversion unit, 41 marker detection unit, 42 shift amount / rotation amount calculation Department, 50 cameras.

Claims (5)

It is an image display device that is configured by stacking two front-side LCD panels and rear-side LCD panels, and displays images by transmitting backlight light in the order of the rear-side LCD panel and the front-side LCD panel. hand,
An RGB controller that generates an RGB image signal after the first processing for displaying the input RGB image signal on the front LCD panel is performed.
An LV controller that controls the rear side LCD panel and generates a first gray image signal after performing a second process for displaying the input RGB image signal on the rear side LCD panel.
The amount of misalignment due to the bonding process between the front LCD panel and the rear LCD panel is a shift amount corresponding to the horizontal and vertical displacement of the rear LCD panel with respect to the front LCD panel, and the front LCD. It has a storage unit in which a rotation amount corresponding to a deviation amount in the rotation direction of the rear-side LCD panel with respect to the panel is stored in advance, and the shift amount and the shift amount and the above-mentioned with respect to the first gray image signal generated by the LV controller. A second gray image signal is generated by performing display position coordinate correction according to the amount of rotation, and the second gray image signal is supplied to the rear side LCD panel to compensate for the amount of misalignment generated in the bonding step. Equipped with a shift / rotation correction unit
The front side LCD panel includes a first marker and a second marker, and the rear side LCD panel contains a third marker and a fourth marker.
The coordinate value of the first marker is (0,0), the coordinate value of the second marker is (x1, y1), and the coordinate value of the third marker is (x2, y2). The coordinate values of the 4 markers are (x3, y3).
The rotation amount θ is expressed by the following equation.

An image display device that will be calculated as. The shift / rotation correction unit is
A parameter memory for storing the shift amount and the rotation amount, and
A first coordinate conversion unit that performs shift correction on the first gray image signal based on the shift amount stored in the parameter memory, and
Based on the amount of rotation stored in the parameter memory, the second coordinate that generates the second gray image signal by performing rotation correction on the first gray image signal after shift correction by the first coordinate conversion unit. The image display device according to claim 1, further comprising a conversion unit. The shift / rotation correction unit is
A parameter memory for storing the shift amount and the rotation amount, and
The shift amount in the horizontal and vertical directions is (-a, -b), the rotation amount in the rotation direction is θ, the coordinate value of the first gray image signal is (x, y), and the second. When the coordinate value of the gray image signal is (x', y'), the following formula

The image display device according to claim 1, further comprising a coordinate conversion unit that simultaneously executes a shift correction based on the shift amount and a rotation correction based on the rotation amount by performing coordinate conversion using the above. The rear side LCD panel is configured to have a larger number of pixels than the front side LCD panel in order to display the entire image by the second gray image signal after the display position coordinate correction is performed. Item 6. The image display device according to any one of Items 1 to 3. It is an image display method in which two LCD panels on the front side and an LCD panel on the rear side are stacked, and the backlight light is transmitted in the order of the LCD panel on the rear side and the LCD panel on the front side to display an image. hand,
After the step of bonding the front side LCD panel and the rear side LCD panel, the first step of photographing the plurality of marker positions of the front side LCD panel and the plurality of marker positions of the rear side LCD panel with a camera,
From the plurality of marker positions of the front side LCD panel and the plurality of marker positions of the rear side LCD panel acquired in the first step, the position deviation amount due to the bonding step of the rear side LCD panel with respect to the front side LCD panel. The second step of calculating the shift amount corresponding to the horizontal and vertical deviation amount and the rotation amount corresponding to the rotation direction deviation amount of the rear side LCD panel with respect to the front side LCD panel and storing them in the storage unit.
The third step of generating the RGB image signal after the first processing for displaying the input RGB image signal on the front LCD panel is performed.
The fourth step of generating the first gray image signal after the second processing for displaying the input RGB image signal on the rear side LCD panel is performed.
The first gray image signal generated in the fourth step is corrected for display position coordinates according to the shift amount and the rotation amount stored in the storage unit to generate the second gray image signal. the second gray image signal possess a fifth step of compensating the positional deviation amount generated in the bonding step by supplying to the rear surface side LCD panel,
The front side LCD panel includes a first marker and a second marker, and the rear side LCD panel contains a third marker and a fourth marker.
The coordinate value of the first marker is (0,0), the coordinate value of the second marker is (x1, y1), and the coordinate value of the third marker is (x2, y2). The coordinate values of the 4 markers are (x3, y3).
The rotation amount θ is expressed by the following equation.

An image display method that will be calculated as.

Images