JP2002189440A - Display, and computer readable recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display having a function for improving the display failure caused by existence of a defective dot effectively and at a low cost. SOLUTION: A display performing display based on input signals is provided with a signal processing part which corrects the input signals and outputs the corrected signals and a display panel 105 which is constituted by being arranged with a plurality of dots which are electrically controlled based on the signals from the signal processing part. The processing part has a LUT(lookup table) 102 in which correction data being data for compensating the display failure caused by the defective dot and data which are predetermined by being related to the input signals are stored and an arithmetic circuit 103 which, when a defective dot being a dot which can not be electrically controlled exists, obtains correction data from the LUT 102 based on the input signals and corrects the input signals of neighboring dots existing at prescribed positions in accordance with the defective dot by using obtained correction data and outputs the corrected signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a liquid crystal display (hereinafter, referred to as "LCD"), a plasma display (hereinafter, referred to as "PDP"), a digital mirror device (hereinafter, referred to as "DMD"), and an electroluminescent device. The present invention relates to a display device having a pixel structure, such as a sense display device, and more particularly to a display device having a function of suppressing display defects caused by dots whose operation (light emission state) cannot be controlled, and a computer-readable recording medium used in the display device. It is.

[0002]

2. Description of the Related Art In a display device such as an LCD, a PDP, and a DMD that displays fine dots that spatially arrange pixels, due to the manufacturing method, the ratio of electric dots is about one in millions. A dot that cannot be controlled in a controlled manner, that is, a dot whose operation in a light emitting state, a light transmitting state, a light reflecting state, and the like cannot be controlled (hereinafter referred to as a “defective dot”) occurs. Since the operation of the defective dot cannot be controlled, the light intensity at the dot cannot be freely changed at the time of display. For this reason, in the pixel having the dot as a component, the range of the luminance and the color of the emitted light is limited. Therefore, even if such a defect exists at an extremely small rate, such as one for several million pixels, the quality of a displayed image is greatly impaired. For this reason, in the display device as described above, the sorting of the shipment must be strictly performed, which raises the production cost of the entire display device.

FIG. 7 is an enlarged view of a portion including a defective dot on a display panel of a display device, and schematically shows a display state thereof. In FIG. 7, 201 is a red dot,
202 is a blue dot and 203 is a green dot. Reference numeral 204 denotes a black matrix unit. These form a display panel having a so-called vertical stripe color arrangement. FIG. 7 shows a case where blue is displayed on the entire surface, and the shining portions are hatched. That is, the following description will be made assuming that only the blue dot 202 is lit.

In FIG. 7, among the blue dots 202, a dot 202a is a defective dot.
Is assumed to be a black spot. In this case, even though the entire surface should be made to shine blue, this dot 20
2a cannot be illuminated. Therefore, color discontinuity occurs in this portion, and visual quality is degraded.

In order to solve such a problem, it is conceivable to improve the manufacturing technique itself so as to suppress the occurrence of defective dots. For example, it is conceivable to improve the precision of the manufacturing apparatus and the cleanness of the manufacturing environment.

In order to minimize the influence on the display when a defective dot occurs, the circuit is burned or sintered by a laser device or the like in accordance with the state of the defective dot, and the defective dot is removed. A countermeasure has been taken to make it inconspicuous by turning it on or off at all times.

As described above, conventionally, the defect rate of the display device has been reduced by two main approaches, namely, the improvement of the manufacturing technology itself and the countermeasure after the manufacturing, and the overall cost has been reduced.

[0008]

However, the above-mentioned conventional countermeasure has a problem in that a large cost is required for performing the countermeasure.

[0009] For example, in order to improve the cleanliness of the manufacturing environment, introduction and maintenance of the production equipment for that purpose requires extremely large costs.

[0010] Further, in measures to make defective dots less noticeable by burning or sintering the circuit with a laser device or the like, the throughput in the measures is extremely small and the manufacturing cost increases. In other words, it takes a long time and individual processing to analyze defects for each display panel, determine which circuit should be corrected for each display panel, and then actually correct it. Yes, it costs a lot to fix. Also, with this measure, the degree of improvement in display defects is small. That is, with this measure, the defective dot can only be shifted to one of the state of always lighting (bright point defect) and the state of always turning off (black point defect). For this reason, defective dots remain after the countermeasure, and the effect is still large. Furthermore, defects that can be made non-defective by this countermeasure are originally very limited defects, and it is difficult to greatly reduce the overall defect rate using only this technique. From such a problem, it is difficult to remarkably reduce the overall failure rate even if measures are taken with a laser device.

As a result, the conventional countermeasure has a problem that the cost for the countermeasure is large, and a large effect cannot be obtained.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a display device having a function of effectively reducing display defects due to the presence of defective dots at low cost and to a display device. It is an object to provide a computer-readable recording medium to be used.

[0013]

SUMMARY OF THE INVENTION A display device according to the present invention is a display device for displaying based on an input signal, and a signal processing for correcting and outputting the input signal. Unit, and a display unit in which a plurality of dots that are electrically controlled based on a signal from the signal processing unit are arranged, and the signal processing unit is caused by a defective dot that is a dot that cannot be electrically controlled. A correction data storage unit that stores correction data, which is data for compensating for display defects to be performed, and that is predetermined data in association with an input signal, and, based on the input signal, when a defective dot exists. A correction unit that obtains correction data from the correction data storage unit and corrects and outputs an input signal of a neighboring dot that is a dot at a predetermined position corresponding to a defective dot using the obtained correction data. It is characterized by having a processing unit.

In the above configuration, by adding a correction data storage unit composed of a memory and the like and a correction processing unit composed of a simple arithmetic circuit, display defects caused by defective dots can be compensated for by neighboring dots. As a result, image quality degradation can be suppressed. This makes it possible to use a display unit (display panel) that has been discarded as a defective product because the number of defective dots has exceeded the reference number by a simple change in the circuit configuration. Thus, the yield can be improved, and the cost of the entire display device can be reduced. This cost reduction is more effective for a display unit having a higher unit price such as a large area and a high density.

Further, in the above-described configuration, the correction data is stored in the correction data storage unit without any modification of the manufacturing environment or a countermeasure using a laser device as in the related art. The effect of suppressing the image quality deterioration can be obtained by an operation of registering information for specifying the position of.
Therefore, it is possible to reduce the time and steps required for compensating for display defects, and it is possible to take measures at low cost.

Further, in the above configuration, various corrections can be made by changing the contents of the correction data. For this reason, a defective dot can be corrected more flexibly than a measure using a conventional laser device, and a more effective measure can be taken.

In the display device according to the present invention, in the above display device, the correction data may further include a correction data associated with a combination of each value of the input signal of the defective dot and each value of the input signal of the neighboring dot. It is preferable that the correction processing unit obtains a corresponding correction signal from the correction data storage unit based on an input signal of a defective dot and an input signal of a neighboring dot, and outputs the obtained correction signal.

In the above configuration, as the processing in the correction processing section, a corresponding correction signal is obtained from the correction data storage section based on the input signal of the defective dot and the input signal of the neighboring dot, and the obtained correction signal is displayed. What is necessary is just to output to a part side. Therefore, it is not necessary for the correction processing unit to perform another operation, and the processing in the correction processing unit can be simplified and the processing speed can be increased.

Alternatively, in the display device according to the present invention, in the above-mentioned display device, the correction data may be an addition value determined in advance in association with each value of the input signal. It is preferable that a corresponding addition value is obtained from the correction data storage unit based on the input signal of the dot, and the addition value is added to the input signal of the neighboring dot and output.

In the above configuration, the correction data stored in the correction data storage section only needs to correspond to each value of the input signal of the defective dot, and the data amount of the correction data can be reduced. Therefore, the capacity required for the correction data storage unit can be small, and the cost of the apparatus can be reduced.

In the display device according to the present invention, in the display device described above, the correction data may be based on a sum of luminance from defective dots and neighboring dots in an actual display and an input signal of defective dots and neighboring dots. Is preferably determined in advance so as to further reduce the difference from the sum of the luminances.

In the above configuration, by making the luminance around the defective dot close to the original luminance indicated by the input signal, it is possible to suppress conspicuous display defects such as the presence of portions having different luminances and to suppress image quality deterioration. . in this case,
Compared with the case where colors are also close to the original colors, correction can be performed with less correction data and simpler calculations, so that an increase in the cost of the apparatus can be further suppressed.

According to the display device of the present invention, in the display device described above, the neighboring dots are dots for displaying a color different from the defective dots, and the correction data is that the defective dots and the neighboring dots are colored in an actual display. It is preferable that the data is used for an operation for further reducing the difference between the color obtained by the above operation and the original color based on the input signals of the defective dot and the neighboring dots.

In the above configuration, by making the color in addition to the luminance close to the original luminance and the color indicated by the input signal, it is possible to further suppress the deterioration of the image quality and bring the image closer to the image to be displayed.

According to another aspect of the present invention, there is provided a computer-readable recording medium storing a program according to the present invention, comprising a display unit having a plurality of dots electrically controlled based on an input signal. Is used to compensate for display defects caused by defective dots when there is a defective dot that is a dot that cannot be electrically controlled and is used in a display device that is not electrically controllable. A process of obtaining correction data based on an input signal, and using the obtained correction data, correcting and outputting an input signal of a neighboring dot which is a dot at a predetermined position corresponding to a defective dot. The processing is performed by a computer.

In the above configuration, the correction data is predetermined in association with the input signal, and when correcting the input signal, the correction data corresponding to the input signal is obtained, and the correction data is used by using the correction data. The following correction can be performed. As a result, processing by the computer can be reduced, so that an inexpensive computer can be used, and the cost of the apparatus can be reduced.

It is preferable that the computer-readable recording medium according to the present invention further records the above-mentioned correction data. Thereby, the program and the correction data can be provided integrally.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment according to the present invention will be described below with reference to FIGS.

[First Embodiment] First, the configuration of the display panel 105 of the present display device will be described with reference to FIG.
FIG. 2 shows a display panel 105 of the display device according to the present embodiment.
FIG. 4 is an enlarged view of FIG. In this display panel 105, one pixel is composed of three dots of red, blue and green, 201 is a red dot, 202
Is a blue dot and 203 is a green dot. Also, 20
4 is a black matrix part. These form a display panel 105 having a so-called vertical stripe color arrangement. FIG. 2 shows the case where blue is displayed on the entire surface, and the shining portions are hatched.

Here, the dot means RGB (R: red,
G: green, B: blue), and the like. A pixel is a minimum display unit of an image including one dot of each of RGB and the like. Each dot represents the brightness (brightness) of each color, and each pixel displays an arbitrary color and brightness. In a monochrome display device, it is usually 1
A pixel is one dot.

In FIG. 2, among the blue dots 202, a dot 202a is a defective dot.
Is assumed to be a dot (black dot) that is always off. In this case, the dot 202a cannot be made to shine although the entire surface should be made to shine blue. Therefore, color discontinuity occurs in this portion, and visual quality degradation (display failure) occurs. A method for suppressing the image quality deterioration and the dots 201a and 203a will be described later.

Next, the configuration of the present display device will be described with reference to FIG. FIG. 1 is a block diagram illustrating a circuit configuration of the display device according to the present embodiment. In FIG. 1, 10
1 is an address detection circuit, 102 is a look-up table (hereinafter, referred to as “LUT”) (correction information holding unit, correction data storage unit), 103 is an arithmetic circuit (correction processing unit), 1
Reference numeral 04 denotes an alignment circuit, and reference numeral 105 denotes a display panel (display unit). Here, the LUT 102 and the arithmetic circuit 103 constitute a signal processing unit.

In this configuration, an input signal (display signal) input to the present display device is input to the arithmetic circuit 103 and the alignment circuit 104. The arithmetic circuit 103 appropriately corrects the input signal that has been input to obtain a corrected output signal, and outputs the corrected output signal to the alignment circuit 104. The alignment circuit 104 generates an applied signal (output signal) based on the input signal and the corrected output signal, and outputs the applied signal to the display panel 105. Here, it is assumed that the input signal is an RGB signal, and the corrected output signal and the applied signal are the same type of signal as the input signal. However, other types of signals may be used. Here, the corrected output signal and the applied signal are the same signal.

The synchronization signal input to the display device is input to the address detection circuit 101. The address detection circuit 101 appropriately generates a flag signal based on the synchronization signal, and outputs the flag signal to the arithmetic circuit 103 and the alignment circuit 104.

The address detection circuit 101 recognizes which position on the display panel 105 the current input signal corresponds to based on the synchronization signal. When the address detection circuit 101 determines that the display position of the current input signal matches the position of a dot (described later) near the defective dot registered in advance in the address detection circuit 101, the current input signal is determined to be a defective dot. Is output to the arithmetic circuit 103 and the alignment circuit 104, indicating that the flag corresponds to the position of the neighboring dot. Specifically, the address detection circuit 101 can be easily configured by a simple combination of a counter circuit, a memory for storing a position, and a comparison circuit (not shown).

When receiving the flag signal, the arithmetic circuit 103 searches and acquires a correction value (correction data) registered in advance corresponding to the value of the input signal with reference to the LUT 102, and further obtains the correction value if necessary. An arithmetic operation is performed to generate a corrected output signal. Then, the arithmetic circuit 103 outputs the corrected output signal to the alignment circuit 104. Note that the correction value is data that compensates for a display defect caused by a defective dot by a dot near the defective dot.

The LUT 102 can be constituted by a storage device such as a memory or a disk device. LUT1
02 holds a registered correction value as a table, and is preferably a nonvolatile storage device. Alternatively, a storage device such as a volatile memory may be used, and the correction value may be read from another read-only memory or a non-volatile storage device such as a disk device each time the power is turned on.
Note that the LUT 102 can hold a plurality of tables as needed.

The alignment circuit 104 adjusts the timing of the input signal that does not pass through the arithmetic circuit 103 and the timing of the corrected output signal that has been corrected through the arithmetic circuit 103, and reconfigures the signal as a series of signals that match the pixel arrangement. The signal is output as an application signal to be applied to the display panel 105.

When the processing time of the arithmetic circuit 103 is negligible with respect to the interval of the input timing (the timing at which an input signal not passing through the arithmetic circuit 103 is input to the alignment circuit 104), the alignment circuit 104 It can be configured only by a switch circuit that selects any of the outputs of the system. If the processing time cannot be ignored, the alignment circuit 104 adjusts the difference between the input signal and the corrected output signal according to the processing time of the arithmetic circuit 103 and the input timing. For this purpose, the alignment circuit 104 may be configured using a storage element such as a flip-flop element or a memory element. Then, in the alignment circuit 104, the input signal for a time corresponding to the processing time of the arithmetic circuit 103 is temporarily stored in the storage element, and the signal stored in the storage element is read out in accordance with the output timing of the arithmetic circuit 103. Can adjust the above deviation.

When the alignment circuit 104 includes the storage element, not only the input signal that does not pass through the arithmetic circuit 103 but also the corrected output signal that has passed through the arithmetic circuit 103 is temporarily stored in the storage element. The stored signal is displayed on the display panel 10 at the timing of, for example, one line or one frame.
5 may be output.

Next, for the display panel 105 in which a defective dot exists, a method for suppressing the image quality deterioration due to the existence of the defective dot based on the correction value registered in the LUT 102 in advance corresponding to the display panel 105. Will be described.

In this embodiment, the value of the applied signal applied to the two adjacent dots is controlled based on the value of the input signal corresponding to the defective dot and two dots of the same color near the defective dot (neighboring dots). Then, a method of compensating the luminance in the area where these dots are located and suppressing the image quality deterioration will be described. The above-mentioned neighboring dots are dots having a predetermined positional relationship with the defective dots.

Here, the value of the correction output signal of the two neighboring dots is determined based on the values of the input signals corresponding to a total of three dots of the defective dot and the two neighboring dots corresponding to the defective dot. . Specifically, a correction output signal corresponding to each combination of the values of the input signals corresponding to the three dots is determined in advance as a correction value (in this case, particularly, a “correction signal”) and registered in the LUT 102. deep. When the display is actually performed, when an input signal corresponding to the three dots is input to the arithmetic circuit 103, a table in the LUT 102 is searched based on a combination of the input signals, and a corresponding correction signal is output. And outputs it to the alignment circuit 104.

Therefore, if the correction signal values corresponding to all combinations of the input signal values corresponding to the above three dots are registered in the LUT 102 with respect to the defective dots, it is possible to correspond to the above three dots. By performing a single search based on the value of the input signal to be obtained, a corresponding correction signal can be obtained.

At this time, the size required for the LUT 102 is 2 × 23 ^m × n (bits) at maximum if the gradation of the input signal is m bits and the gradation of the correction signal is n bits.
If the correction signal does not need to correspond to all combinations of the input signals corresponding to the three dots, the LUT 10
The size required for 2 is smaller than above.

Here, in the present embodiment, a case is considered in which correction is performed to equally distribute the luminance that a defective dot should originally represent to two neighboring dots corresponding to the defective dot. That is, the luminance represented by the input signal of the defective dot j is Y
j, the luminances represented by the input signals of the two neighboring dots i, k are Yi, Yk, and the luminances represented by the correction signals of the two neighboring dots i, k are Yi ′, Yk ′. Yi ′ = Yi + Yj / 2 Yk ′ = Yk + Yj / 2.

In this case, if the values of the input signals corresponding to Yi, Yj, Yk and the values of the correction signals corresponding to Yi ′, Yk ′ are registered in the LUT 102 in association with each other, L
By performing a single search on the UT 102, a correction signal can be obtained without performing other arithmetic processing. Y
Since the values of the correction signals corresponding to i ′ and Yk ′ each depend only on the values of two input signals, the size of the LUT 102 is 2 × 2 ^{2 m} × n (bits) at the maximum.

When the accuracy corresponding to all the gradations is not required, the size of the LUT 102 can be reduced by thinning out the gradations.

Further, if necessary, a correction signal is obtained by performing interpolation processing such as averaging on the correction value obtained by searching the LUT 102, thereby obtaining the LUT while maintaining the required accuracy.
It is also possible to reduce the size of 102. For example,
The correction value for the defective dot is set in the LUT 102 every N stages.
, And a value between the registered values may be calculated as a correction signal by linear interpolation.

The details are as follows. Yi, Y above
j, Yk, Yi ′, Yk ′, and the brightness represented by the correction value registered in the LUT 102 for the neighboring dot i is fi
(Yi, yj × N, Yk), LU for neighboring dot k
The luminance represented by the correction value registered in T102 is represented by fk (Yi,
yj × N, Yk). Here, yj = [Yj / N]
([] Is a Gaussian symbol, yj represents the largest integer not exceeding Yj / N), and fi (Yi, yj ×
N, Yk) and fk (Yi, yj × N, Yk) are associated with each of N stages of Yj. At this time,

[0051]

(Equation 1)

[0052]

(Equation 2)

Thus, the correction value can be calculated by linearly interpolating the correction value. At this time, LUT1
The size required for 02 is 1 / N as compared with the case where a correction signal is registered in association with all values of Yj.

Since the correction signal does not normally depend on the position of the defective dot on the display panel 105, even when there are a plurality of defective dots on the display panel 105, the arithmetic circuit 103 performs the RG operation.
One table may be provided in the LUT 102 for each B.

As described above, the correction signal is calculated in advance and LU
By registering it in T102 or the like, a correction signal can be obtained with a simple circuit configuration, and the cost of the display device can be reduced. Even when correction based on a correction value that is difficult to express in a calculation formula such as an actual measurement value is required, an appropriate correction signal can be obtained by registering the actual measurement result in the LUT 102 or the like in advance. .

Further, by making the contents registered in the LUT 102 changeable, a plurality of display devices having different correction methods can be manufactured without changing the hardware configuration.

In this embodiment, neighboring dots of the same color,
For example, a case has been described in which defective dots are compensated for by dots of the same color in adjacent pixels. However, the pixels need not always be adjacent pixels and may be adjacent pixels. For example, a neighboring pixel may be separated by one pixel from a pixel including a defective dot. Further, the adjacent pixel (neighboring pixel) is not limited to the horizontal adjacent pixel (neighboring pixel), and may be an oblique or vertical adjacent pixel (neighboring pixel). In other words, "adjacent"
("Nearby") means any of horizontal, vertical, and oblique directions. Further, the number of pixels (dots) for compensating for defective dots is not limited to two pixels (dots), but may be four pixels (dots) or more pixels (dots).

As described above, according to the present display device, in a display device configured by spatially arranging dots constituting fine pixels, visual interference caused by the presence of defective dots is reduced. It is characterized by having a means (arithmetic circuit 103) for controlling a signal to be applied to a dot near a defective dot.

According to this configuration, even when a defective dot exists on the display panel 105, by controlling the signal applied to the neighboring dot, for example, the luminance substantially equal to the original luminance of the defective dot is compensated by the neighboring dot. It becomes possible to do. As a result, it is possible to suppress visual disturbance (display failure) due to the presence of the defective dot. In addition, this makes it possible to avoid the above-described problem that has occurred in the case of a countermeasure using a conventional laser device.

This display device is a display device that performs display based on an input signal, and is electrically controlled based on a signal processing unit that corrects and outputs the input signal and a signal from the signal processing unit. Display panel 10 in which a plurality of dots are arranged
5 is provided. The LUT 102 stores correction data, which is data for compensating a display defect caused by a defective dot and is predetermined data in association with an input signal. An arithmetic circuit 103 for obtaining correction data from the LUT 102 based on the input signal, correcting the input signal of a neighboring dot at a predetermined position corresponding to the defective dot using the obtained correction data, and outputting the corrected data. have.

This makes it possible to use a display panel that has been discarded as a defective product because the number of defective dots has exceeded the reference number, with a simple circuit configuration. Thus, the yield can be improved, and the cost of the entire display device can be reduced. This cost reduction is more effective as the display panel 105 has a higher unit price such as a large area and a high density.

In the present display device, the correction data is stored in the correction data storage unit, and the operation for registering information for specifying the position of the neighboring dot corresponding to the defective dot for each display panel 105 is performed by the operation. Can suppress image quality degradation due to the presence of. Therefore, it is possible to reduce the time and steps required for compensating for display defects, and it is possible to take measures at low cost.

Further, in the present display device, various corrections can be made by changing the contents of the correction data. For this reason, a defective dot can be corrected more flexibly than a measure using a conventional laser device, and a more effective measure can be taken.

In the present display device, the sum of the luminance of the defective dot and the n (n is an integer of 1 or more) dots near the defective dot is the original luminance of the defective dot and the n dots near the defective dot. It is preferable to control the signals applied to the n dots in the vicinity of the defective dot so as to approximate (preferably, substantially equalize). As a result, a state substantially equal to the original luminance of the defective dot can be created in the vicinity of the defective dot, and display defects due to the presence of the defective dot can be suppressed. In this case, assuming that the n dots do not originally emit light at all, the sum of the luminance of the n dots is substantially equal to the original luminance of the defective dot.
The signals applied to the individual dots are controlled.

In order to control the applied signal, it is generally necessary to perform relatively complicated signal processing, so that the cost of an additional circuit required for each display device increases. On the other hand, in the present display device, by registering the correction result of the signal processing in the LUT 102 in advance, the above processing can be realized at low cost by a simple additional circuit.

In this case, even when a complicated correction that is difficult to express by a mathematical expression, such as an actual measurement value, is required,
This can be realized by registering correction results based on actual measurement values or the like in advance, and more display panels can be made non-defective.

Further, in this case, by making the contents registered in the LUT 102 changeable, it is possible to cope with a display panel requiring a different correction without changing the hardware configuration. For this reason, it is possible to select the most appropriate correction method according to the use of the display device, the state of the defective dot, and the like. As a result, since various defective dots can be handled, a display panel which was conventionally discarded as a defective product can be used as a non-defective product for a display device, and the overall defective rate can be greatly reduced. Will be possible. Further, as a result, the display quality after correction can be made much better than the conventional countermeasure in which the defective dot can only be shifted to either always-on or always-off.

[Embodiment 2] In this embodiment, based on the input signal values corresponding to a defective dot and two dots of different colors (neighboring dots) adjacent to the defective dot,
A method of controlling the value of the applied signal applied to the two neighboring dots to compensate for the luminance in the area where these dots are located and to suppress the image quality deterioration will be described.

In this embodiment, the basic configuration of the display device is the same as that shown in FIG.

Here, as shown in FIG. 2, when blue is displayed on the entire surface, the blue dot 202a which is a defective dot is compensated for.
Dot 201a and green dot 203 adjacent to
control a. That is, the blue dot 2 which is a defective dot
By changing the brightness of the red dot 201a and the green dot 203a adjacent to the blue dot 202a, the brightness substantially equal to the original brightness of the blue dot 202a is changed to the blue dot 2a.
By causing it near 02a, it acts so as to reduce visual disturbance due to defective dots.

Here, by applying a correction output signal corresponding to the original luminance of the blue dot 202a to the red dot 201a and the green dot 203a, the original luminance of the blue dot 202a is substantially equal. Reproduce the brightness.

Assuming that the luminance can be simply added, in order to compensate for the luminance of the blue dot 202a, the adjacent red dot 201a and green dot 203a have the original luminance of the blue dot 202a, respectively. What is necessary is just to control so that it may become 1/2. Actually, since the visibility of humans varies depending on the color, the luminance Y is expressed as Y = 0.30R + 0.59G + 0.11B. Here, R, G, and B are the values of the input signals (see FIG. 1) of the primary colors red, green, and blue, respectively, and γ was set to 1. Also, R, G and B
The primary chromaticity and the white reference chromaticity according to the NTSC television standard.

Here, γ is the value of the exponent part when the relationship between the input signal to the display device and the display characteristic (luminance characteristic) output from the display panel of the display device is expressed by an exponential function. Yes, with different values depending on the target display device or input signal.

From the above equation, for example, as shown in FIG.
Only the blue dot 202 shines and the red and green dots 2
In order to compensate for the same luminance as when the blue dot 202a, which is a defective dot, normally shines, when performing display without shining 01.203 by shining the red dot 201a and the green dot 203a. The values of R and G may be determined so as to satisfy 11B = 0.30R + 0.59G.

The red dot 201a and the green dot 203a adjacent to the blue dot 202a are not the dots that should be illuminated originally.
Assuming that the same value is applied as an application signal for compensating for a defective dot to R.a, it is possible to set R = G = K × B by using an appropriate coefficient K. 11B = (0.30 + 0.59) × K × B holds.

When the dots around the blue dot 202a are also the dots that should be illuminated, if the luminance can be simply added, the corrected output signals R2 and G2 corresponding to the input signals R1, G1 and B1 have the above K. In general, it can be expressed as follows: R2 = R1 × 10 × B1 G2 = G1 × 10 × B1

FIG. 3 is a block diagram showing a detailed configuration of the arithmetic circuit (correction processing unit) 113 for performing the above processing. This arithmetic circuit 113 is the arithmetic circuit 10 of the first embodiment.
3 has a different internal structure. Note that FIG. 3 shows only a part necessary for performing the above processing.

The correction value K × for each value of the input signal B is determined in advance.
B is calculated and registered in the LUT 102 as an added value. The search circuit 113c searches for and obtains an addition value for the blue input signal B1, and outputs it to the addition circuits 113a and 113b. The addition circuit 113a adds the addition value from the search circuit 113c and the red input signal R1 to generate a red dot 201.
and outputs a correction output signal R2 to be applied to a. Similarly, the addition circuit 113b also calculates the addition value and the green input signal G1.
And outputs a correction output signal G2 to be applied to the green dot 203a.

In this case, if the gradation of the input signal is m bits and the gradation of the output of the added value is n bits, the size of the LUT 102 is 2 ^m × n (bits) at the maximum.

As described above, according to the present display device, in a display device in which dots constituting fine pixels are spatially arranged, a display defect due to the presence of a defective dot is compensated for. In particular, one or more adjacent dots are provided, and a means (arithmetic circuit 113) for controlling a signal applied to a dot different in color from the defective dot is provided.

This display device can obtain the same effects as those obtained by the display device in the first embodiment.
Further, in the present display device, since the capacity of the LUT 102 can be smaller than that of the display device in Embodiment 1, the device can be configured at lower cost.

[Embodiment 3] In the present embodiment, not only the difference in luminance due to a defective dot is compensated, but also the color obtained by coloring n dots (neighboring dots) near the defective dot, A method of controlling a value of an applied signal applied to n dots near a defective dot so as to compensate for a difference from an original color indicated by an input signal corresponding to the defective dot and n dots in the vicinity thereof explain.

In this embodiment, the basic configuration of the display device is the same as that shown in FIG.

Here, two neighboring dots of different colors adjacent to the defective dot, that is, the dots 201a and 203a in FIG. 2 are adopted as the n dots in the vicinity of the defective dot, and are applied to the two neighboring dots. Controls the value of the applied signal. Also, as the color difference, CIE
(1976) Using L ^* a ^* b ^* color difference, C as color value
IE (1976) L ^* a ^* b ^* color values will be used.

The CIE (1976) L ^* a ^* b ^* color values are described in, for example, Japanese Patent Application Laid-Open No. 9-329495 and are well-known values, and are defined as follows.

That is, the input signals of the defective dot and two neighboring dots adjacent to the defective dot are represented by R _i ,
G _i , B _i, and tristimulus values X _i , Y _i , Z _i are calculated under the condition of 8 bits (256 gradations).

[0087]

(Equation 3)

Then, the above CIE (1976) L^*a
^*b^*L per color value^*, A^*, B ^*Are

[0089]

(Equation 4)

## EQU10 ## It should be noted that the subscript i = 1 for the input value and the subscript i = 2 for the output value.

The CIE (1976) L ^* a ^* b ^* color difference value ΔE ^* is

[0092]

(Equation 5)

Is as follows.

Here, taking the case where the red dot is a defective dot (black dot defect) as an example, the input signals (R ₁ ,
G ₁ , B ₁ ) and the corrected output signals (R ₂ , G ₂ ,
The condition for controlling G ₂ and B ₂ in B ₂ ) to minimize the color difference will be described. Further, here, it is assumed that two neighboring dots adjacent to the defective dot are not supposed to shine, and the sum of the luminances of the two neighboring dots becomes substantially equal to the original luminance based on the input signal of the defective dot. Then, a method of minimizing the color difference under the condition of ΔL ^* = 0 will be described.

Then, ΔE ^* is

[0096]

(Equation 6)

Here, since ΔL ^* = 0, from Y ₁ = Y ₂ ,

[0098]

(Equation 7)

Since the red dot is a defective dot, R ₂ = 0, and from the above equation (1),

[0100]

(Equation 8)

[0101] In _{^{addition, ΔL * = 0 ⇔ L 1}} * = L 2 *
よ り From Y ₁ = Y ₂ and R ₂ = 0,

[0102]

(Equation 9)

Then,

[0104]

(Equation 10)

Thus, the input signals (R ₁ , G ₁ ,
B ₁ ), so that the value on the right side of the above equation (7) becomes smaller, preferably, the value on the right side becomes minimum.
It is determined the value of the corrected output signal G ₂ green Dottohe by calculation can color difference to a minimum.

[0106] The value of the corrected output signal B ₂ of Dottohe blue can be obtained as follows. That is,
From the above equation (7),

[0107]

[Equation 11]

B ₂ that satisfies the condition may be adopted.

The G ₂ and B ₂ obtained as described above are signals to be applied to two neighboring dots (green dot and blue dot) adjacent to the red dot which is a defective dot. As a result, it is possible to reproduce a state substantially equal to the original color (color) of the red dot, which is a defective dot, in the vicinity of this dot, and it is possible to suppress image quality deterioration due to the defective dot.

The configuration of the arithmetic circuit at this time is shown in FIG.
This will be described in more detail based on FIG. 4 is a block diagram illustrating a detailed configuration of the arithmetic circuit 123 that performs the processing of the present embodiment. The arithmetic circuit 123 has a different internal structure from the arithmetic circuits 103 and 113 of the first and second embodiments. FIG. 4 shows only the parts necessary for performing the following processing. Also, in FIG.
2 is omitted (see FIG. 1 for the LUT 102).

As described above, when the red dot is a defective dot, the correction output signal G ₂ for the adjacent green dot
May be calculated in advance so that ΔE is minimized by the above equation (8), and registered in one table of the LUT 102.

In this case, the correction output signal G_TwoIs strictly
Force signal (R₁, G₁, B₁), But the total
According to the calculation, the input signal B₁With the input signal
(R₁, G ₁) Does not change much
Therefore, in this circuit configuration, the input signal (R₁,
G₁) Is approximated by the value calculated using
ing. Note that each combination of the input signals (R1, G1) is
In determining the corresponding approximation, the input signal B₁Each value of
Corrected output value G_TwoAnd the calculated corrected output value
G_TwoMay be adopted. In FIG.
The LUT 102 is searched by the search circuit 123a, and
Correction output signal G_TwoAnd output.

The correction output signal B ₂ for the blue dot adjacent to the defective red dot is given by the above equation (9).

[0114]

(Equation 12)

Can be described as follows. Therefore, f
₁ ~f operation result of the advance in the LUT 102 ₅ may be registered as a respective table, find the calculation results by the respective search circuit 123b~123f 4, the calculation result of f ₁ ~f ₅ by obtaining Can be obtained. The search circuits 123b to 123f and the addition circuit 1
And 23g and subtraction circuit 123h can be obtained a corrected output signal B ₂ by combining as shown in FIG. Specifically, the outputs of the search circuits 123c to 123e are added by an adder circuit 123g, and the output of the adder circuit 123g is added to the search circuit 123f in a subtraction circuit 123h.
Subtracting the output value, it retrieves the corrected output signal B ₂ by the search circuit 123b on the basis of the output result of the subtraction circuit 123h, may be output. Thus, the search circuits 123b to
The arithmetic circuit 123 can be configured with a simple circuit configuration including a combination of the 123f, the addition circuit 123g, and the subtraction circuit 123h. Thereby, the correction output signal B can be easily obtained.
It becomes possible to get ₂ .

In this case, the input signal is m bits, and f _{1 to} f
_If the calculation result of ₅ and the correction output signal are n bits,
The table size in the LUT 102 corresponding to the search circuit 123a is a maximum of 22 ^m × n (bits), and the search circuit 12
The size of each table corresponding to 3c to 123e is at most 2 ^m × n (bits), and the size of the table in the LUT 102 corresponding to the search circuit 123f is at most 2 ⁿ ×
n (bit) and the size of the table corresponding to the search circuit 123b are as follows.
Since there are n bits equal to the output from c to 123e,
The maximum is 2 ⁿ × n (bits). Therefore, the size of the LUT 102 in this case is a maximum (2 ^2m + 3 × 2 ^m + 2 ×
2 ⁿ ) × n (bits).

As described above, the calculation result and the like are previously stored in the LUT 1
By registering it in 02, even a complicated correction process can be performed with a simple circuit configuration. As a result, the device can be configured using a less expensive arithmetic circuit.

Further, in the present display device, a color value close to the original color value of a pixel including a defective dot is displayed, or a color value closest to the average color value is displayed in consideration of the color values. It is also possible to do so. This makes it possible to significantly reduce the degree of display defects remaining after the correction.

In this embodiment, the case where adjacent dots are used as adjacent dots has been described, but they need not always be adjacent dots. For example, they may be separated by one dot, and are not limited to adjacent dots in the horizontal direction.
Neighboring dots in an oblique direction or a vertical direction may be used. Further, not only two adjacent dots but also three or more dots may be controlled. Of course, CIE (1976) L ^*
The calculation may be performed using color values other than the a ^* b ^* color values.

[Embodiment 4] In the present invention, means for controlling a signal applied to a display panel is a CPU device or a D
It may be a general-purpose arithmetic device (computer) such as an SP device. In this case, the arithmetic device is implemented by the program (software) recorded in the display device according to the first embodiment.
What is necessary is just to operate as any of the arithmetic circuits 103, 113, and 123 described in 3 to 3. Note that this program may be supplied to the present display device by a recording medium. In this case, the recording medium may include a correction value to be registered in the LUT 102. As a recording medium,
Non-volatile memory elements such as a mask ROM, EPROM, and flash memory, and disk devices such as a hard disk are included.

FIG. 5 is a block diagram showing a circuit configuration of the display device according to the present embodiment. The display device includes a control unit 501 that determines whether an input signal corresponds to a dot near a defective dot based on a synchronization signal, and an application signal that processes the input signal and applies the signal to a display panel 505. An arithmetic unit 502 that generates the signal, a ring buffer 503 that temporarily holds the input signal, and an output unit 504 that reads and outputs the applied signal generated by the arithmetic unit 502 are provided. Note that the calculation unit 502 is configured by a general-purpose calculation device such as the CPU device or the DSP device. The calculation unit 502 also controls the control unit 501 and the output unit 504.

Next, processing for suppressing image quality deterioration due to defective dots by the above-described apparatus configuration will be described with reference to FIGS. FIG. 6 is a flowchart showing the flow of processing by the display device of FIG.

First, the control unit 501 recognizes to which position the current input signal corresponds on the display panel 505 based on the synchronization signal, and determines the dot at the corresponding position as a dot near the defective dot. It is determined whether or not there is (Step S1). This process can be easily realized by using a counter, for example, and comparing it with a value registered in advance as a position of a dot in the vicinity of a defective dot.

If the dot corresponding to the current input signal is not a dot in the vicinity of the defective dot, the arithmetic unit 502
To store the input signal as an applied signal at the position of the storage address of the ring buffer 503 (step S).
3). On the other hand, if the dot corresponding to the current input signal is a dot in the vicinity of the defective dot, the arithmetic unit 502 performs a correction process on the input signal (step S5).
2), the result is used as an applied signal as a ring buffer 503
And the storage address of the ring buffer 503 is advanced (step S3).

This processing is executed, for example, by a program stored in a storage device in the arithmetic unit 502 and readable by the arithmetic unit 502. This program causes the arithmetic unit 502 to operate as one of the arithmetic circuits 103, 113, and 123 in the first to third embodiments. The program may be recorded on a recording medium and supplied to the display device.

Then, it is determined whether or not the dot subjected to the above processing is the dot at the end of the screen (step S4). If it is the dot at the end of the screen, the storage address is reset so that the next applied signal is stored as the first dot on the screen (step S5).

Thereafter, the output timing (display panel 50
5, the output unit 504 reads out the stored application signal stored at the read address of the ring buffer 503, outputs the signal to the display panel 505, and advances the read address of the ring buffer 503. (Step S6).

Then, it is determined whether or not the dot to which the applied signal has been output is the dot at the end of the screen (step S7). If it is the dot at the end of the screen, the read address is reset and the next applied signal is read from the head of the ring buffer 503 (step S).
8).

It should be noted that the operation timing of the arithmetic
When the arithmetic processing in 02 is short enough, the ring buffer 503 may be omitted and the arithmetic unit 502 may directly output to the output unit 504. Further, if the arithmetic processing in the arithmetic unit 502 is longer than the timing at which the input signal is sent, the input signal may be missed. May need to be written to the ring buffer 503 in some cases.

In the present embodiment, the correction processing and the control processing of each unit are processed by software using the arithmetic unit 502. However, these control processing is processed by hardware using another circuit, and the correction processing is performed. Only a part of processing such as calculation for processing and timing adjustment accompanying the processing may be processed by software using the calculation unit 502.

As described above, in the present display device, correction values are registered in advance, so that a low-cost display device having a relatively low-speed arithmetic circuit can perform correction processing by software processing. It becomes possible.

In the present embodiment, a program used for a display device having a display unit (display panel 505) in which a plurality of dots electrically controlled based on an input signal are arranged, or a computer storing the program Use a readable recording medium. In this program,
If there is a defective dot that cannot be electrically controlled, in step S2, this is data for compensating for display defects caused by the defective dot by the method described in the first to third embodiments. A process of acquiring correction data that is predetermined data in association with the input signal, and using the acquired correction data, a neighboring dot that is a dot at a predetermined position corresponding to the defective dot. And outputting the corrected input signal to the computer.

By executing this program in the arithmetic section 502, the correction data is predetermined in association with the input signal, and when correcting the input signal, the correction data corresponding to the input signal is obtained. The correction as described in the first to third embodiments can be performed using the correction data. Accordingly, processing by the computer can be reduced, so that an inexpensive computer can be used, and the cost of the display device can be reduced.

Further, the above-described correction data may be included in a computer-readable recording medium on which the program is recorded. Thus, the program and the correction value can be provided integrally.

Note that the display device according to the present invention is, for example,
It can be suitably used for CD, but is not limited to this, and may be used for PDP, D
The present invention can be similarly applied to other display devices such as an MD and an electroluminescence display device. In addition, the present invention is not limited to a display device that performs color display with one display panel, but includes a plurality of panels (display units) corresponding to each color, and performs color display by combining light from these panels. The present invention can be similarly applied to a projection display device (for example, a liquid crystal projector). The present invention is not limited to color display,
The present invention is also suitably applied to a monochrome display device.

Although the case where the defective dot is a black dot defect has been mainly described above, the present invention can similarly be applied to the case where the defective dot is a bright spot defect. In other words, the correction may be performed so as to reduce the luminance of the adjacent dot so that the sum of the luminance of the defective dot having the bright spot defect and the luminance of the neighboring dot becomes the closest to the total of the luminance when the defective dot is normally lit. However, since human eyes are more sensitive to bright spots than black spots, the above correction may not provide a sufficient effect compared to the case of black spot failure. In such a case, the bright spot defect may be changed to a black spot defect by a measure using the above-described laser device, and then the correction may be performed by the above method. As a result, it is possible to obtain a sufficient effect even for a defective bright spot.

[0137]

As described above, the display device according to the present invention includes the signal processing unit and the display unit, and the signal processing unit associates the input signal with the input signal in order to compensate for a display defect caused by a defective dot. A correction data storage unit for storing the obtained correction data, and a correction data storage unit for obtaining correction data from the correction data storage unit based on the input signal, and using the obtained correction data, a neighboring dot at a predetermined position corresponding to the defective dot. And a correction processing unit that corrects and outputs the input signal.

In the above configuration, by adding a correction data storage section composed of a memory or the like and a correction processing section composed of a simple arithmetic circuit, a display defect caused by a defective dot can be compensated for by neighboring dots. As a result, image quality degradation can be suppressed.

Further, in the above configuration, the effect of suppressing the image quality deterioration can be obtained by an operation of storing correction data in the correction data storage unit and registering information for specifying the position of the defective dot for each display unit. Can be Therefore, it is possible to reduce the time and steps required for compensating for display defects, and it is possible to take measures at low cost.

Further, in the above configuration, various corrections can be made by changing the contents of the correction data. For this reason, a defective dot can be corrected more flexibly than a measure using a conventional laser device, and a more effective measure can be taken.

In the display device according to the present invention, in the display device described above, the correction data may further include a correction data associated with a combination of each value of the input signal of the defective dot and each value of the input signal of the neighboring dot. It is preferable that the correction processing unit obtains a corresponding correction signal from the correction data storage unit based on the input signal of the defective dot and the input signal of the neighboring dot, and outputs the obtained correction signal.

In the above configuration, as the processing in the correction processing section, the corresponding correction signal is obtained from the correction data storage section based on the input signal of the defective dot and the input signal of the neighboring dot, and the obtained correction signal is displayed. What is necessary is just to output to a part side. Therefore, it is not necessary for the correction processing unit to perform another operation, and the processing in the correction processing unit can be simplified and the processing speed can be increased.

Alternatively, in the display device according to the present invention, in the above-mentioned display device, the correction data may be an addition value determined in advance in association with each value of the input signal. It is preferable that a corresponding addition value is obtained from the correction data storage unit based on the input signal of (1), and the addition value is added to the input signal of the neighboring dot and output.

In the above configuration, the correction data stored in the correction data storage section only needs to correspond to each value of the input signal of the defective dot, and the data amount of the correction data can be reduced. Therefore, the capacity required for the correction data storage unit can be small, and the cost of the apparatus can be reduced.

According to the display device of the present invention, in the display device described above, the correction data is further based on the sum of the luminance from the defective dot and the neighboring dot in the actual display and the input signal of the defective dot and the neighboring dot. Is preferably set so as to make the difference from the sum of the luminances smaller.

In the above configuration, by making the luminance around the defective dot close to the original luminance indicated by the input signal, it is possible to suppress a conspicuous display defect in which a portion having a different luminance is present, and to suppress image quality deterioration. .

According to the display device of the present invention, in the display device described above, the neighboring dots are dots that display a color different from the defective dots, and the correction data is that the defective dots and the neighboring dots in the actual display are colored. It is preferable that the data is used for an operation for further reducing the difference between the color obtained by the above operation and the original color based on the input signals of the defective dot and the neighboring dots.

In the above configuration, by making the color in addition to the luminance close to the original luminance and the color indicated by the input signal, it is possible to further suppress the deterioration of the image quality and bring the image closer to the image to be displayed.

The computer-readable recording medium on which the program according to the present invention is recorded is data for compensating for a display defect caused by a defective dot when there is a defective dot. A process of acquiring correction data, which is predetermined data, based on an input signal, and a process of correcting and outputting an input signal of a neighboring dot at a predetermined position corresponding to a defective dot using the acquired correction data. And a program that causes a computer to execute the program.

In the above configuration, the correction data is predetermined in association with the input signal, and when correcting the input signal, the correction data corresponding to the input signal is obtained, and the correction data is used by using the correction data. The following correction can be performed. As a result, processing by the computer can be reduced, so that an inexpensive computer can be used, and the cost of the apparatus can be reduced.

The computer-readable recording medium according to the present invention preferably further records the correction data. Thereby, the program and the correction data can be provided integrally.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a circuit configuration of a display device according to a first embodiment of the present invention.

2 is an enlarged view of a display panel of the display device of FIG. 1 and schematically shows a display state thereof.

FIG. 3 is a block diagram showing a detailed configuration of an arithmetic circuit of a display device according to a second embodiment of the present invention.

FIG. 4 is a block diagram showing a detailed configuration of an arithmetic circuit of a display device according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a circuit configuration of a display device according to a third embodiment of the present invention.

6 is a flowchart showing a flow of processing in the display device of FIG.

FIG. 7 is an enlarged view of a portion including a defective dot on a display panel of the display device, and schematically shows a display state thereof.

[Explanation of symbols]

 Reference Signs List 101 address detection circuit 102 LUT 103 arithmetic circuit 113 arithmetic circuit 123 arithmetic circuit 104 alignment circuit 105 display panel (display unit) 501 control unit 502 arithmetic unit 503 ring buffer 504 output unit

Claims (7)

[Claims] 1. A display device for performing display based on an input signal, comprising: a signal processing unit for correcting and outputting the input signal; and a plurality of dots electrically controlled based on a signal from the signal processing unit. The signal processing unit is a data for compensating for a display defect caused by a defective dot which is a dot that cannot be electrically controlled, and is a data set in advance corresponding to an input signal. A correction data storage unit for storing the correction data, and when a defective dot exists, obtains correction data from the correction data storage unit based on the input signal and uses the obtained correction data to respond to the defective dot. A correction processing unit for correcting and outputting an input signal of a neighboring dot which is a dot at a predetermined position. 2. The display device according to claim 1, wherein the correction data is a correction signal associated with a combination of each value of the input signal of the defective dot and each value of the input signal of the adjacent dot. A display device, wherein the correction processing unit obtains a corresponding correction signal from the correction data storage unit based on an input signal of a defective dot and an input signal of a neighboring dot, and outputs the obtained correction signal. 3. The display device according to claim 1, wherein the correction data is an addition value determined in advance in association with each value of the input signal; A corresponding addition value is obtained from the correction data storage unit, and the addition value is added to an input signal of a neighboring dot and output. 4. The display device according to claim 1, wherein the correction data is a sum of luminance from a defective dot and a neighboring dot in an actual display, and an input signal of the defective dot and a neighboring dot. A display device which is determined in advance so as to reduce the difference from the original luminance sum based on the display device. 5. The display device according to claim 1, wherein the neighboring dot is a dot for displaying a color different from the defective dot, and the correction data is obtained by coloring the defective dot and the neighboring dot in an actual display. The display device is data used for an operation for further reducing a difference between a color to be obtained and an original color based on input signals of defective dots and neighboring dots. 6. A method according to claim 1, wherein said display device includes a display unit having a plurality of dots electrically controlled on the basis of an input signal. A process of acquiring correction data, which is data for compensating display defects caused by defective dots and is predetermined data in association with an input signal, based on the input signal, and using the acquired correction data, A computer-readable recording medium on which a program for causing a computer to execute a process of correcting and outputting an input signal of a neighboring dot which is a dot at a predetermined position corresponding to a defective dot is recorded. 7. The computer-readable recording medium according to claim 6, wherein the correction data is recorded.