JP5881184B2 - Display device and display method - Google Patents

Description

  The present invention relates to a display device and a display method for correcting screen unevenness based on a use environment such as backlight driving power and device internal temperature.

In a liquid crystal display device that displays an image using a backlit liquid crystal display panel, unevenness in luminance and chromaticity occurs depending on the position in the screen.
In the liquid crystal display device described in Patent Document 1, when an image is displayed using a liquid crystal display panel with a backlight, the liquid crystal display panel of the liquid crystal display panel is in accordance with compensation voltage data corresponding to a temperature distribution due to lighting of a backlight light source. The drive voltage is controlled to compensate for temperature unevenness in the panel surface.

FIG. 4 shows a configuration of a liquid crystal display device according to the background art.
In the liquid crystal display device of this example, the screen unevenness measurement value / correction value storage unit 101 of the display device stores the measurement unevenness measurement value or correction value data of the liquid crystal display device.
When using the screen unevenness measurement value stored in the display unevenness measurement value / correction value storage unit 101 of the display device, the target unevenness characteristic stores the target unevenness characteristic in which there is no screen unevenness and the screen has a uniform color. The comparison unit 103 compares the target unevenness characteristic from the storage unit 102 with the screen unevenness measurement value / correction value storage unit 101 of the display device, and the correction value calculation unit 104 corrects the correction value based on the comparison result. Is calculated and output to the correction value transmission unit 105. On the other hand, when the screen unevenness measurement value / correction value storage unit 101 stored in the display device is used, the screen unevenness measurement value / correction value storage unit 101 of the display device uses the correction value transmission unit 105. Output the correction value.

The correction value transmission unit 105 outputs the input correction value to the 3DLUT circuit 106.
The 3DLUT circuit 106 stores, in a lookup table (LUT: Look Up Table), the correspondence between the combination of the pixel gradation I and the display position x, y in the screen and the output value for the input video signal. The output value corresponding to the combination of the input pixel gradation I and the display position x, y in the screen is output to the liquid crystal panel 107. The contents of this LUT are rewritten corresponding to the correction value from the correction value transmitting unit 105 and correspond to the correction value. The display positions x and y in the screen represent coordinate values of coordinate axes that are orthogonal to each other in the screen.
The liquid crystal panel 107 displays a video (image) according to the input value from the 3DLUT circuit 106 on the display screen. The backlight light source 108 illuminates the liquid crystal panel 107 from the display back surface.

Japanese Utility Model Publication No. 2-148127

http: // www. nec. co. jp / techrep / ja / journal / g09 / n03 / 090307. html

However, in a display device that uses a backlight, even when the same individual is used, the characteristics of screen unevenness vary depending on the environmental temperature and display luminance. This is because the light emission efficiency and color of the backlight, which is a cause of screen unevenness, have temperature dependency, and the temperature of each point in the backlight varies depending on the backlight driving power and the temperature in the apparatus.
2 to 4 shown on the Web page according to Non-Patent Document 1 show the temperature-dependent characteristics of a fluorescent lamp similar to the light source for the backlight, and the emission luminance changes depending on the temperature. It can be seen that the change characteristics are different for each color of R / G / B. Also from this, it is estimated that the luminance and chromaticity distribution in the screen changes depending on the backlight driving power and the temperature in the apparatus.

In the display device as shown in FIG. 4 described above, the measurement environment for the screen unevenness of the display device is not considered at all in the setting of the measurement value or correction value of the display device, such as the backlight driving power and the temperature in the device, and the screen unevenness measurement is performed. Since the value or the correction value is fixed for each individual, there is a problem in that the unevenness of the screen due to the influence of the use environment as described above cannot be suppressed.
The objective of this invention is providing the display apparatus and display method which solve the subject mentioned above.

  A first display device according to the present invention includes a display unit that displays an image, a light source for backlight that illuminates from the back of the display unit, and backlight driving power that detects driving power of the light source for backlight. Detecting means, and screen unevenness correcting means for correcting screen unevenness by correcting the signal of the image displayed by the display unit in accordance with the driving power detected by the backlight driving power detecting means. It is characterized by that.

  A second display device according to the present invention includes a display unit that displays an image, a light source for backlight that illuminates from the back of the display unit, an in-device temperature detection unit that detects the temperature in the device, and the device A screen unevenness correcting means for correcting screen unevenness by correcting the signal of the image displayed by the display unit in accordance with the temperature inside the apparatus detected by the internal temperature detecting means. To do.

  In the first display method according to the present invention, the driving power of a light source for backlight that illuminates from the back of a display unit that displays an image is detected, and an image displayed by the display unit according to the detected driving power. By correcting this signal, screen unevenness is corrected.

  According to the second display method of the present invention, the temperature in the apparatus including the display unit that displays the image and the light source for the backlight that illuminates from the back of the display unit is detected, and the temperature in the apparatus is detected. The image unevenness is corrected by correcting the signal of the image displayed by the display unit.

  The display device and the display method according to the present invention have an advantage that screen unevenness can be appropriately corrected and suppressed.

1 is a schematic block diagram illustrating a configuration of a liquid crystal display device according to a first embodiment of the present invention. It is a figure which shows the example of the correction characteristic of the screen nonuniformity obtained by the liquid crystal display device which concerns on embodiment of this invention. It is a schematic block diagram which shows the structure of the liquid crystal display device which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the liquid crystal display device which concerns on background art.

A first embodiment of the present invention will be described.
FIG. 1 is a schematic block diagram showing the configuration of the liquid crystal display device according to the first embodiment of the present invention.
The liquid crystal display device includes a screen unevenness change characteristic storage unit 1, a temperature / backlight drive power information detection unit 2, a primary correction data creation unit 3, a screen unevenness characteristic storage unit 4 of the display device, and a secondary correction. A data creation unit 5, a correction value transmission unit 6, a 3DLUT circuit 7, a liquid crystal panel 8, and a backlight light source 9 are provided.

The screen unevenness change characteristic storage unit 1 stores information on the screen unevenness change characteristics of the display device with respect to changes due to the use environment such as the device internal temperature (in this embodiment, the temperature in the liquid crystal display device) and the backlight driving power.
The temperature / backlight drive power information detection unit 2 detects information about the usage environment such as the temperature in the apparatus and the backlight drive power, and outputs the detected information to the primary correction data creation unit 3.
The primary correction data creation unit 3 creates primary correction data based on the information stored in the screen unevenness change characteristic storage unit 1 and the detection result obtained from the temperature / backlight drive power information detection unit 2 to obtain the secondary correction data. Output to the correction data creation unit 5. Specifically, the primary correction data creation unit 3 refers to the information stored in the screen unevenness change characteristic storage unit 1 and corresponds to the detection result obtained from the temperature / backlight drive power information detection unit 2. Correction data for compensating for the variation characteristic of screen unevenness is created as primary correction data.

  Here, as information on the use environment stored by the screen unevenness change characteristic storage unit 1 and information on the use environment detected by the temperature / backlight drive power information detection unit 2, information on the backlight drive power and information on the temperature in the apparatus. Both are preferably used, but as another configuration example, only the information on the backlight driving power may be used, or only the information on the temperature in the apparatus may be used. Specifically, the screen unevenness change characteristic storage unit 1 stores information on the change characteristics of screen unevenness caused by changes in both the backlight drive power and the temperature in the apparatus, and the temperature / backlight drive power information detection unit 2 A configuration for detecting information on both the backlight drive power and the temperature in the apparatus, or the screen unevenness change characteristic storage unit 1 stores information on the change characteristics of the screen unevenness caused by the change in the backlight drive power. The configuration in which the backlight drive power information detection unit 2 detects information on the backlight drive power, or the screen unevenness change characteristic storage unit 1 stores information on the change characteristics of the screen unevenness caused by the change in the temperature in the apparatus. A configuration in which the temperature / backlight drive power information detection unit 2 detects information on the temperature in the apparatus can be used.

In addition, as a method of detecting information on the backlight driving power, for example, a method of calculating the backlight driving power from the control value of the backlight light source 9 based on characteristics measured in advance can be used. As the control value of such a light source, one or more of voltage, current, blinking duty, etc. can be used. As a simple example, the control value of the light source and the backlight driving power when the control value is used are stored in association with each other, and the backlight corresponding to the control value when the control value of the light source is detected. By reading the driving power, the backlight driving power can be calculated.
When the backlight is multi-primary, it is preferable to use the total or average value of the backlight driving power for each color as the backlight driving power, but other configurations may be used.

Further, as an example, the temperature in the apparatus is detected by a temperature sensor provided in the apparatus.
In addition, any position may be used as a position for detecting the temperature in the apparatus. For example, a configuration for detecting a temperature at an arbitrary position of the liquid crystal panel 8 or a temperature at an arbitrary position of the backlight light source 9 may be used. It is preferable to use a configuration for detecting. As another example, a configuration for detecting the temperature at an arbitrary position on the main board (not shown) can be used.
Note that the temperature inside the apparatus is determined approximately by the room temperature and the backlight driving power. Further, since there may be a delay in the transmission of temperature, even when the temperature of the backlight light source 9 is used as the internal temperature of the apparatus, the information on the backlight driving power is also used together with the information, and the screen unevenness Is preferably corrected.

The screen unevenness characteristic storage unit 4 of the display device stores information on the screen unevenness characteristics of the display device when the use environment such as the internal temperature and the backlight driving power is set to a predetermined fixed value.
Here, as in this embodiment, when both the in-device temperature and the backlight drive power information are used in the screen unevenness change characteristic storage unit 1 and the temperature / backlight drive power information detection unit 2, the display device As the information in the screen unevenness characteristic storage unit 4, information in which both of them are fixed values is used. As another configuration example, when only the information on the backlight driving power is used in the screen unevenness change characteristic storage unit 1 or the temperature / backlight driving power information detection unit 2, the screen unevenness characteristic storage unit 4 of the display device. As this information, at least the backlight driving power is used as a fixed value. In addition, when information on only the in-device temperature is used in the screen unevenness change characteristic storage unit 1 or the temperature / backlight drive power information detection unit 2, the information in the screen unevenness characteristic storage unit 4 of the display device is at least in the device. A fixed temperature is used.

The secondary correction data creation unit 5 creates secondary correction data based on the primary correction data from the primary correction data creation unit 3 and the information stored in the screen unevenness characteristic storage unit 4 of the display device, thereby correcting the correction value. Output to the transmitter 6. Specifically, the secondary correction data creation unit 5 considers the characteristics of the variation represented by the primary correction data with respect to the characteristics of the screen unevenness stored in the screen unevenness characteristic storage unit 4 of the display device. Are created as secondary correction data. That is, from the fixed value of the information on the screen unevenness characteristic of the display device when the use environment such as the internal temperature of the device and the backlight driving power is set to a predetermined fixed value (information of the screen unevenness characteristic storage unit 4 of the display device). From the information (primary correction data) corresponding to the amount of change, correction data (secondary correction data) considering both of these is created.
Here, the secondary correction data creation unit 5 may obtain an output value by performing a predetermined calculation using, for example, two input values as parameters, or a combination of two input values and one output value. The correspondence may be stored, and the output value may be obtained from the two input values based on the stored contents.

  The information stored in the screen unevenness change characteristic storage unit 1 and the information stored in the screen unevenness characteristic storage unit 4 of the display device are, for example, the results of measurements performed in advance or theoretical simulations. It is determined based on the result. As an example, as information in the screen unevenness characteristic storage unit 4 of the display device, information can be set when the device is warmed up at the time of factory shipment or the like and the internal temperature and backlight drive power are set to a constant value. .

The correction value transmission unit 6 outputs a correction value corresponding to the input secondary correction data to the 3DLUT circuit 7. Here, the value of the secondary correction data and the correction value may be the same value or different values.
The 3DLUT circuit 7 stores, in a look-up table (LUT), a correspondence relationship between a combination of a pixel gradation I and display positions x and y in the screen and an output value with respect to an input video signal. An output value corresponding to a combination of the pixel gradation I and the display position x, y in the screen is output to the liquid crystal panel 8. The contents of this LUT are rewritten corresponding to the correction value from the correction value transmission unit 6 and correspond to the correction value. The display positions x and y in the screen represent coordinate values of coordinate axes that are orthogonal to each other in the screen.

Here, the 3DLUT circuit 7 is realized by using a 3DLUT that changes a video signal, and includes 3 inputs of the gradation I of the pixel, the x position in the pixel screen, and the y position thereof. A corresponding pixel gradation signal is output. With this configuration, a correction value corresponding to the pixel gradation and the display position can be used.
The liquid crystal panel 8 displays a video (image) according to the input value from the 3DLUT circuit 7 on the display screen. The backlight light source 9 illuminates the liquid crystal panel 8 from the back of the display.

In the present embodiment, the 3DLUT circuit 7 corrects the pixel gradation I in accordance with the correction value from the correction value transmission unit 6 for the input video signal, and outputs the corrected video signal. Thereby, the correction amount of each point in the screen can be changed based on the current use environment (in this embodiment, the backlight driving power and the temperature in the apparatus). Uniform display can be realized by correcting luminance unevenness and color unevenness in the image.
Here, for example, both luminance and chromaticity may be used as targets for correcting screen unevenness, or only luminance may be used, or only chromaticity may be used. Note that the gradation information includes, for example, luminance information and chromaticity information.

  As described above, in the liquid crystal display device according to the present embodiment, by using the driving power of the backlight light source 9 and the temperature in the device as parameters, by changing the correction value for correcting the screen unevenness, for example, Further, it is possible to control screen unevenness correction according to the result of simply estimating the temperature change of the backlight. In the liquid crystal display device according to the present embodiment, the display color can be made uniform (suppressed) by suppressing unevenness in luminance and chromaticity at each point in the screen. Note that, as an aspect of making the luminance and chromaticity constant, an aspect in which the luminance and chromaticity are not necessarily strictly constant but substantially constant may be used.

Here, for correction of screen unevenness, for example, ideally, it is desirable to install a temperature sensor at each point of the light source and perform correction based on the measured temperature distribution. In many cases, it is difficult to realize the structure because the cost is too high. On the other hand, in the screen unevenness correction in the present embodiment, it is not always necessary to install a temperature sensor at each point of the light source. Therefore, the structure can be simplified and the cost can be reduced.
In the industrial field where strict color reproduction is required, for example, periodic calibration using the characteristics of the center of the screen of the display device may be performed. However, in such a method, due to screen unevenness due to environmental temperature or display brightness. It is difficult to obtain desired color characteristics over the entire screen. On the other hand, in the screen unevenness correction in the present embodiment, it is possible to obtain desired color characteristics over the entire screen.

  In the liquid crystal display device according to the present embodiment, the liquid crystal panel 8 is used as the display unit, and the backlight driving power detection unit and the in-device temperature detection unit are configured by the function of the temperature / backlight driving power information detection unit 2. Depending on the functions of the screen unevenness change characteristic storage unit 1, the primary correction data creation unit 3, the screen unevenness characteristic storage unit 4, the secondary correction data creation unit 5, the correction value transmission unit 6 and the 3DLUT circuit 7 of the display device. Screen unevenness correcting means is configured.

FIG. 2 shows a liquid crystal display device (the proposed device) according to the present embodiment and a liquid crystal display device (comparative device) as shown in FIG. 4, using a liquid crystal panel (LCD: Liquid Crystal Display). An example of screen unevenness correction characteristics (in this case, gradation correction amount) in the case where control is performed so as to achieve uniform luminance and chromaticity in the screen is shown.
As shown in FIG. 2, in the comparison device, the correction characteristic is fixed even when the backlight driving power changes, but in this embodiment, when the backlight driving power changes, the unevenness characteristic in the screen changes. Corresponding to the change (not shown), the correction characteristic (map shape) changes for each backlight driving power. According to this configuration, for example, an effect that screen unevenness can be appropriately suppressed even when the environmental temperature or the display luminance changes is obtained.

  The screen unevenness correction in the present embodiment is also effective in suppressing screen unevenness during long-term use, for example. As a specific example, in color management applications that maintain a constant display brightness, the light emission efficiency of the backlight light source decreases with age and the internal temperature and backlight drive power change (increase). The unevenness correction can appropriately cope with such a case.

A second embodiment of the present invention will be described.
FIG. 3 is a schematic block diagram showing the configuration of the liquid crystal display device according to the second embodiment of the present invention.
The liquid crystal display device according to this embodiment includes a plurality of n display device screen unevenness characteristic storage units 11-1 to 11-n, a temperature / backlight power information detection unit 12, and a correction value selection / calculation unit 13. As a component similar to that shown in FIG. 1, a correction value transmission unit 6, a 3DLUT circuit 7, a liquid crystal panel 8, and a backlight light source 9 are provided. .

The screen unevenness characteristic storage units 11-1 to 11-n of the respective display devices respectively display information on the screen unevenness characteristics of the display device when the usage environment such as the device internal temperature and the backlight driving power is set to a predetermined fixed value. Remember. Here, the screen unevenness characteristic storage units 11-1 to 11-n of each display device store information on the screen unevenness characteristics corresponding to different usage environments (in this embodiment, the internal temperature and backlight driving power). I remember it.
The temperature / backlight power information detection unit 12 detects information about the usage environment such as the temperature in the apparatus and the backlight driving power, and outputs the detected information to the correction value selection / calculation unit 13.
The correction value selection / calculation unit 13 generates correction data based on information from the screen unevenness characteristic storage units 11-1 to 11-n of the display device and information from the temperature / backlight power information detection unit 12, and corrects the correction data. Output to the value transmitter 6. Specifically, the correction value selection / calculation unit 13 includes one storage unit corresponding to information from the temperature / backlight power information detection unit 12 (the screen unevenness characteristic storage units 11-1 to 11-n of the display device). Any one of them) is selected, and reference is made to the information in the selected storage unit, and correction data that compensates for the variation characteristic of screen unevenness is calculated and created. Alternatively, correction data may be calculated by interpolating from data in two adjacent screen unevenness characteristic storage units.

Here, as in the case of the first embodiment, information on the use environment stored in the screen unevenness characteristic storage units 11-1 to 11-n of the display device and the use detected by the temperature / backlight power information detection unit 12. As the environmental information, it is preferable to use both the backlight driving power information and the apparatus internal temperature information as in this embodiment, but as another configuration example, only the backlight driving power information is used. Alternatively, only information on the temperature in the apparatus may be used.
The operations of the correction value transmission unit 6, the 3DLUT circuit 7, the liquid crystal panel 8, and the backlight light source 9 are the same as those in the first embodiment. The correction value transmission unit 6 inputs the secondary correction data in the first embodiment, whereas in the present embodiment, the correction value transmission unit 6 inputs the correction data from the correction value selection / calculation unit 13 and uses it as correction data. Is the same as the secondary correction data in the first embodiment.

As described above, also in the liquid crystal display device according to this embodiment, the same effect as that of the first embodiment can be obtained with respect to correction of screen unevenness.
In the liquid crystal display device according to this embodiment, the liquid crystal panel 8 is used as a display unit, and the function of the temperature / backlight power information detection unit 12 constitutes a backlight driving power detection unit and an in-device temperature detection unit. The screen unevenness correction means is configured by the functions of the screen unevenness characteristic storage units 11-1 to 11-n, the correction value selection / calculation unit 13, the correction value transmission unit 6, and the 3DLUT circuit 7 of the display device.

  Here, one or more processing units (for example, the primary correction data creation unit 3, the secondary correction data creation unit 5, and the correction value transmission unit 6) shown in FIG. 1 or one or more processing units shown in FIG. With regard to the processing unit (for example, the correction value selection / calculation unit 13 and the correction value transmission unit 6), a program for realizing the function of the corresponding processing unit is recorded on a computer-readable recording medium and recorded on this recording medium. The screen unevenness correction may be performed by causing the computer system to read and execute the program. Here, the “computer system” includes an OS and hardware such as peripheral devices.

Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used.
The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Further, the “computer-readable recording medium” includes a medium that holds a program for a certain period of time, such as a volatile memory inside a computer system serving as a server or a client. Further, the program may be for realizing a part of the functions described above, and may be capable of realizing the functions described above in combination with a program already recorded in the computer system. . Alternatively, the program may be stored in a predetermined server, and the program may be distributed (downloaded or the like) via a communication line in response to a request from another device.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.

The present invention can be applied not only to a direct-view display device and display method using a liquid crystal panel, but also to a projection display device and display method such as a projector, and also to other display devices and display methods. May be.
The present invention exhibits an excellent effect particularly in a field where a display device and a display method for performing stable color reproduction are required, such as a graphic design, a printing shop, and a medical display.

DESCRIPTION OF SYMBOLS 1 Screen unevenness change characteristic memory | storage part 2 Temperature / backlight drive electric power information detection part 3 Primary correction data creation part 4 Screen unevenness characteristic memory | storage part 5 Secondary correction data creation part 6 Correction value transmission part 7 3DLUT circuit 8 Liquid crystal Panel 9 Light source for backlight 11-1 to 11-n Screen unevenness characteristic storage unit of display device 12 Temperature / backlight power information detection unit 13 Correction value selection / calculation unit 101 Screen unevenness measurement value / correction value storage unit of display device DESCRIPTION OF SYMBOLS 102 Target nonuniformity memory | storage part 103 Comparison part 104 Correction value calculation part 105 Correction value transmission part 106 3DLUT circuit 107 Liquid crystal panel 108 Light source for backlights

Claims (2)

A display for displaying an image;
A light source for backlight that illuminates from the back of the display unit;
Backlight driving power detection means for detecting the driving power of the light source for the backlight;
In-apparatus temperature detecting means for detecting the temperature in the apparatus;
Screen unevenness change characteristic storage means for storing information of change characteristics of screen unevenness with respect to changes in the driving power and the temperature;
Screen unevenness characteristic storage means for storing information on the characteristics of screen unevenness when the driving power and the temperature are set to predetermined fixed values;
According to the drive power detected by the backlight drive power detection means, the temperature in the apparatus detected by the in-apparatus temperature detection means, and the screen unevenness change characteristic information stored in the screen unevenness change characteristic storage means Correction data creation means for creating correction data,
By correcting the signal of the image displayed by the display unit in accordance with the correction data created by the correction data creating means and the screen unevenness characteristic information stored in the screen unevenness characteristic storage means, the screen unevenness is corrected. Screen unevenness correction means for correcting
A display device comprising: While detecting the driving power of the light source for the backlight that illuminates from the back of the display unit that displays the image, the temperature in the device is detected,
Stores information on change characteristics of screen unevenness with respect to changes in the driving power and the temperature,
Stores information on screen unevenness characteristics when the driving power and the temperature are set to predetermined fixed values.
Create correction data according to the detected drive power, the temperature in the device, and the information of the stored change characteristics of the screen unevenness,
In accordance with the created correction data and stored information on the characteristics of the screen unevenness, by correcting the signal of the image displayed by the display unit, the screen unevenness is corrected,
A display method characterized by that.

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