JP2009229952A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device which controls brightness not to dazzle a viewer and eye-friendly color correction, by considering effects of ages, viewing distances, brightness and color temperatures of a room as human visual characteristics. <P>SOLUTION: The brightness and color correction of a display screen are set from relationship of preferable brightness and preferable color temperature obtained from experiment. Specifically, the image display device is provided with the display screen, a screen illuminance measurement part for measuring illuminance, a setting condition input part for setting viewer information, an operation part for obtaining brightness of the display screen the viewer prefers, a screen brightness control part for determining maximum brightness of the display screen, a screen color correction control part for determining a color of the display screen, and a display panel drive part for driving a display panel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image display device.

  In recent years, television receivers used in ordinary homes have been replaced with cathode ray tube displays, and flat flat panel displays such as liquid crystal display devices and plasma display devices have become widespread. Flat panel displays are becoming brighter due to improved device performance. However, increasing the brightness of the display device increases the visibility, but causes fatigue due to glare and eye fatigue.

  For these reasons, a method of mounting a light receiving element for measuring brightness on a display device and adjusting the display brightness of the screen in accordance with the surrounding brightness environment is generally performed. When the periphery is dark, the display brightness is adjusted to be low, and when it is bright, the display brightness is adjusted to be high. This suppresses visibility in bright environments and glare in dark environments.

  On the other hand, it has been reported that a person suffers from a decrease in visual acuity in terms of brightness and color as they age. As an example, it is known that blue is difficult to see. For this reason, a display device that is easy to see and preferable to the viewer is not only related to the surrounding brightness environment, but also related to the visual acuity, age, and viewing distance of the viewer. The conventional method for adjusting the brightness of the display device does not always reflect the visibility and preferences of the viewer.

  In many display devices, brightness and color can be set by a viewer's own operation. However, many viewers use a display device without adjusting these image quality settings due to the difficulty and troublesomeness of operability, resulting in suboptimal display devices that are difficult to see or result in a heavy burden on the eyes. It keeps watching with the setting of.

  For example, in a conventional display device, the viewer sets the viewer condition using a screen setting corresponding to age or a camera image on the display device, so that the surrounding environment can be set according to the age of the viewer. Adjustment of the combined display luminance was performed, and the difference in visual function with respect to the sense of brightness was automatically compensated (for example, Patent Document 1).

In another conventional display device, by operating the age dial, the color correction amount, the defocus correction amount, and the spatial frequency characteristic correction amount are independently set according to the age of the viewer, and the display screen Has been proposed (for example, Patent Document 2).
In another conventional display device, in order to set the character size and color scheme corresponding to the environment, age, and individual differences, it is presented to the user regarding the readability and resolution of characters, and based on the setting conditions A display device for setting display brightness and color correction has been proposed (for example, Patent Document 3).

JP 2007-279405 (first term, FIG. 1) Japanese Patent Laid-Open No. 9-97333 (Section 6, FIG. 3) JP2003-44033 (first term, Fig. 7)

  By the way, in the display device of Patent Document 1, brightness correction is automatically performed, but color correction is not automatically performed. Therefore, it is necessary for the viewer to perform color correction.

  In Patent Document 2, color correction is performed. Color correction was performed according to the age because it tends to be difficult to see short wavelengths when becoming elderly. However, color correction based on age has not always been a color correction preferable to individuals.

  Further, in Patent Document 3, in order to cope with this individual difference, a color correction test is performed on the user, and luminance and color correction are performed by reflecting the correction value. This is burdensome to the user because it is cumbersome to adjust until it is set. Moreover, in order to set the character size and character color scheme, the readability and resolution of the character can be evaluated, but it does not necessarily correspond to the visibility and preference of the natural image.

  In Patent Documents 2 and 3, the illumination environment is measured based on only brightness, but it does not correspond to the color temperature of surrounding illumination.

  The present invention has been made in view of the above-mentioned problems, and calculates screen brightness using parameters corresponding to visual acuity, age, the size and viewing distance of an image display device, illuminance and color temperature environment of a display surface, and the like as parameters. To provide an image display device that calculates color correction based on the brightness of the screen and the surrounding color temperature environment, adjusts the brightness of the display screen according to the brightness environment and the characteristics of the viewer, and performs color correction. Objective.

    A display screen, a screen illuminance measuring unit for measuring the illuminance in the vicinity of the display screen, a setting condition input unit for setting information on the viewer, the illuminance in the vicinity of the display screen, the information on the viewer, and the viewing distance. Based on the calculation unit for determining the brightness of the display screen that the viewer feels preferable, and the screen brightness that determines the maximum brightness of the display screen based on the brightness of the display screen that the viewer feels preferable A controller, a screen color correction controller that determines the color of the display screen based on the brightness of the display screen that the viewer feels preferable, and a maximum brightness and color correction of the display screen that are determined by the screen brightness. There is provided an image display device comprising a display panel driving unit for driving a display panel so as to achieve the maximum luminance and chromaticity determined by the control unit and the screen color correction control unit.

  According to the image display device of the present invention, images can be displayed with preferable brightness and color according to the brightness of various brightness environments and the age group of the viewer, and long-time viewing is performed. Even in the case of the viewer, it becomes possible to reduce the fatigue of the viewer. In addition, power consumption can be reduced by suppressing the brightness of the screen.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a configuration of an image display apparatus according to Embodiment 1 of the present invention. The image display apparatus according to the first embodiment includes a screen illuminance measurement unit 1, a setting condition input unit 2, a background luminance calculation unit 3, a storage unit 4, a luminance adjustment constant calculation unit 5, a brightness sensation luminance calculation unit 6, and a screen. Luminance control unit 7, display panel drive unit 8, video signal luminance calculation unit 9, display screen 10, visual constant calculation unit 11, video signal analysis unit 12, viewing angle constant calculation unit 13, imaging unit 14, color correction calculation unit 20, A screen color correction control unit 21 and a video signal chromaticity circle remaining part 22 are provided. The background luminance calculation unit 3, the luminance adjustment constant calculation unit 5, the brightness sensation luminance calculation unit 6, the visual constant calculation unit 11, the visual angle constant calculation unit 13, and the color correction calculation unit 20 are collectively referred to as a calculation unit.

  The screen illuminance measuring unit 1 is one or a plurality of light receiving elements arranged in the vicinity of the display screen 10, and is composed of, for example, a silicon photodiode and an amplifier that have been corrected for visibility. The setting condition input unit 2 includes a remote control light receiving unit, and can receive various conditions from a remote controller (not shown) by a viewer's operation. The imaging unit 14 includes an image sensor and an image processing device, captures an image of the viewer, and obtains the distance (viewing distance) between the viewer and the display screen 10 and the age of the viewer by image processing. it can.

  Incidentally, the brightness and visibility of the display device are affected by the color of the displayed image. Here, the color tone is a white balance determined by the blending ratio of RGB, and may be described as a color temperature. In the NTSC (National Television Standards Committee) standard, 6500K is used, and in Japan, 9300K is 9300K. It is used. That is, it is necessary not only to adjust the brightness of the display device based on the viewing distance, visual acuity, and age of the viewer, but also to perform a preferable color correction process.

  In order to clarify the above, the results of preliminary experiments conducted in advance will be described in detail.

  FIG. 2 shows the result of an experiment conducted to obtain the relationship between the preferred set luminance Lw and the preferred color temperature (white color) Ct, which is the basic concept of the function incorporated in the color correction calculation unit 20. It is.

The experiment was conducted with 20 elderly people (10 men and 10 women) from 63 to 79 years old as subjects.
First, a first experiment regarding the preferable luminance Lw, which is the horizontal axis of FIG. 2, will be described. The room in which the experiment was performed was equipped with illumination having a color temperature of 6500K, and the illumination was adjusted so that the illuminance on the screen of the image display device installed in the room was 100 lx. The images displayed on the image display device are ten images with different average luminance levels, which were taken in a studio equipped with illumination with a color temperature of 6500K. The subject looked at these 10 images and adjusted the brightness of the image display device to the brightness he felt was preferable for each of the images. For example, if the image display device is a liquid crystal display device, the viewer determines the brightness of the backlight for each of ten images. Then, when the white image is displayed with the brightness of each backlight determined for each of the ten images, the luminance is measured, and the average value of the obtained ten luminances is preferable for the subject. The brightness was felt. The horizontal axis of FIG. 2 represents the brightness that the subject felt favorable.

Next, a second experiment regarding the vertical axis in FIG. 2 will be described. The environment of the room in which the experiment was performed is the same as in the first experiment. In the second experiment, the subject views images with three color temperature settings (9500K, 6500K, and 5000K) adjusted to a peak luminance of 100 cd / m ² . Then, each image was evaluated as a preferable image or an unfavorable image. The evaluation value ranges from −0.15 to +0.15, and the positive direction indicates “preferable” and the negative direction indicates “not preferable”. This evaluation value corresponds to the vertical axis of FIG.

For example subjects 600 cd / ^{m 2} about the display luminance is adjusted with preferred is answered display color temperature 9300K is preferred with respect to the image of 100 cd / ^{m 2.} Moreover, the test subject who adjusted that the display brightness | luminance of about 100 cd / m < ² > is preferable has shown that the color temperature of 5000K is preferable. The peak luminance of the image viewed by the subject in the second experiment was evaluated for the 300 cd / m ² image in addition to the 100 cd / m ² image. The experimental results showed almost the same tendency.

From this experimental result, it was found that elderly people who prefer high-brightness display prefer display with high color temperature, and elderly people who prefer low-brightness display prefer display with low color temperature. Thus, Expression (1) is obtained as a relational expression between the display luminance Lw selected as preferable and the preferable color temperature Ct.
Ct = cLw ^β + C _E (1)

Here, β is a visual constant representing the relationship between brightness and color temperature, c is a color correction adjustment constant, and _CE is a viewing environment constant. The visual constant β is a constant related to age, and different values obtained from experimental results are used for young and elderly people. The color correction adjustment constant c is a constant mainly related to visual acuity and color preference, and _CE is a constant mainly related to the color temperature and brightness of illumination in the viewing environment.

Next, the operation of the display device according to the present invention will be described.
The screen illuminance measurement unit 1 is installed toward the viewer, measures the illuminance near the center of the display screen 10 (screen illuminance Ei), and outputs this to the background luminance calculation unit 3. In addition, when it is difficult to install near the center of the display screen 10, there is no problem even if it is installed near the display screen 10 and the measured illuminance is approximated to the screen illuminance Ei.

  The setting condition input unit 2 receives information such as a viewer's age and visual acuity, a background luminance calculation constant Re used for background luminance calculation, a viewing distance, and the like by remote control operation and the received information is stored in the storage unit 4. Output to. Here, when information such as age is not input by remote control operation or the like, a predetermined default value may be used. Further, the viewing distance and age may be obtained by image processing from the image of the viewer imaged by the imaging device provided in the imaging unit 14 and output to the setting condition input unit 2.

The screen brightness illuminance Ei is input from the screen illuminance measurement unit 1 to the background brightness calculation unit 3 and the background brightness calculation constant Re is input from the storage unit 4.
La = Re × Ei (2)
Further, the background luminance La is calculated and output to the storage unit 4. The background luminance La is further output from the storage unit 4 to the brightness sensation luminance calculation unit 6.

A viewing distance L stored in the storage unit 4 is input to the viewing angle constant calculation unit 13. The video signal analysis unit 12 analyzes the video signal, calculates an effective area S of the video pattern displayed on the display screen 10, and outputs the result to the viewing angle constant calculation unit 13. From these pieces of information, the visual angle constant calculation unit 13 calculates the expression (3).
φ = 2 × Tan ⁻¹ (√ (S / π) / L) (2)
The viewing angle φ is obtained based on the above. The viewing angle φ is output to the storage unit 4 and recorded in the storage unit 4. Note that the effective area of the video pattern may be simply the area of the display screen, or the area of the display screen multiplied by a constant smaller than 1. Thereby, the video signal analysis part 12 can be made unnecessary.

  The viewing angle φ recorded in the storage unit 4 is output to the brightness adjustment constant calculation unit 5. In the luminance adjustment constant calculation unit 5, the luminance adjustment constant k is obtained from the input viewing angle φ. In obtaining the luminance adjustment constant k, a table that gives the luminance adjustment constant k from the viewing angle φ may be used, or may be obtained by an appropriate function calculation. The obtained luminance adjustment constant k is output to the storage unit 4 and recorded. The luminance adjustment constant k is mainly determined by the viewing angle φ, but also depends on the age. Therefore, the age adjustment information k is received from the storage unit 4 and the luminance adjustment constant k is obtained more accurately using the age together with the viewing angle φ. Is also effective.

  The visual information calculation unit 11 receives the viewer's age and viewing angle φ stored in the storage unit 4. The visual information calculation unit 11 has a table for selecting a visual constant α related to luminance and a visual constant β related to color, so that the visual constants α and β suitable for the visual condition of the viewer can be obtained. Is output to the storage unit 4, and the visual constants α and β are recorded in the storage unit 4. If necessary, the visual constant and the preference of the viewer are input from the storage unit 4 and the visual constants α and β are determined according to the age and the visual angle φ of the viewer. And β can also be determined.

The background luminance La, the luminance adjustment constant k, and the visual constant α are output from the storage unit 4 to the brightness sensation luminance calculation unit 6. From this information, the brightness sensation luminance calculation unit 6 calculates the equation (4).
Lw = k × La ^α (4)
Based on the above, the luminance Lw that the viewer feels preferable is calculated, and this Lw is output to the screen luminance control unit 7 and the color correction calculation unit 20.

Visual constants α and β and visual acuity information are output from the storage unit 4 to the color correction calculation unit 20. Further, luminance Lw that the viewer feels preferable is input from the brightness sensation luminance calculation unit 6, and the color temperature Ct that the viewer feels preferable is calculated based on the expression (1) based on these pieces of information. This Ct is output to the color correction control unit 21. _CE used in the calculation of Ct is a constant related to the color temperature and brightness of the illumination in the viewing environment, so that the viewer may input a constant, or a general proof condition for the home environment is a constant. It may be.

  Here, when the brightness Lw that the viewer feels preferable is operated by remote control operation or the like, the color temperature Ct may be calculated in accordance with this Lw.

Ct is obtained based on the equation (1), but Lw may be measured from a predetermined image and obtained as a fixed value based on the measured Lw.
Ct may be a variable that measures Lw from different images and changes it stepwise instead of a continuous value.

  Thus, the color temperature can be automatically set even for the brightness condition set by the viewer, and the color setting operation becomes unnecessary.

  The screen luminance control unit 7 displays a brightness display that is not dazzling for the viewer based on the luminance distribution of the video signal obtained by the video signal luminance calculation unit 9 and the Lw obtained from the brightness sensation luminance calculation unit 6. Then, the maximum luminance value of the video signal is determined, and a signal for adjusting the brightness of the display screen 10 is output to the display panel drive unit 8. The display panel drive unit 8 controls the brightness of the display screen based on this signal.

  Based on the chromaticity of the video signal obtained by the video signal chromaticity calculation unit 22 and the Ct obtained from the color correction calculation unit 20, the screen color correction control unit 21 generates a luminance that is preferable for the viewer and a color display that is easy to see. Thus, the color of the video signal is determined, and a signal for adjusting the color of the display screen 10 is output to the display panel drive unit 8. The display panel drive unit 8 controls the color of the display screen based on this signal.

  An image display system that obtains brightness and color adapted to the visual characteristics of a viewer based on such set condition values as age, visual acuity, visual distance, display size, background luminance, room lighting, etc. It can display images with brightness and color that viewers of each age group find desirable in various brightness environments, and even when viewed for a long time, It becomes possible to reduce the fatigue of the person. In addition, power consumption can be reduced by reducing the brightness of the screen.

Embodiment 2. FIG.
FIG. 3 is a block diagram showing the configuration of the image display apparatus according to Embodiment 2 of the present invention. The image display device according to the second embodiment includes a screen illuminance measurement unit 1, a setting condition input unit 2, a background luminance calculation unit 3, a storage unit 4, a luminance adjustment constant calculation unit 5, a brightness sensation luminance calculation unit 6, and a screen. Luminance control unit 7, display panel drive unit 8, video signal luminance calculation unit 9, display screen 10, visual constant calculation unit 11, video signal analysis unit 12, viewing angle constant calculation unit 13, imaging unit 14, color correction calculation unit 20, A screen color correction control unit 21, a video signal chromaticity calculation unit 22, and a viewing environment color temperature calculation unit 31 are provided. The background luminance calculation unit 3, the luminance adjustment constant calculation unit 5, the brightness sensation luminance calculation unit 6, the visual information calculation unit 11, the visual angle constant calculation unit 13, the color correction calculation unit 20, and the viewing environment color temperature calculation unit 31 These are collectively called a calculation unit.

The screen illuminance measurement unit 1 is a plurality of light receiving elements arranged in the vicinity of the display screen 10, and outputs information C corresponding to the chromaticity of the irradiating light to the viewing environment color temperature calculation unit 31. The viewing environment color temperature calculation unit 31 outputs the environment color temperature constant _CE to the recording unit 4 based on this information.

The color correction calculation unit 20 uses the environmental color temperature constant _CE obtained by the visual environment color temperature calculation unit 31, the luminance Lw, visual acuity information, and visual information β that are determined to be preferable and obtained by the brightness sensation luminance calculation unit 6. Originally, the color correction value is obtained by the equation (1) and output to the screen color correction control unit 21.

  Based on the chromaticity of the video signal obtained by the video signal chromaticity calculation unit 22 and the Ct obtained from the color correction calculation unit 20, the screen color correction control unit 21 generates a color display that is not dazzling for the viewer and easy to see. Thus, the color of the video signal is determined, and a signal for adjusting the color of the display screen 10 is output to the display panel drive unit 8. The display panel drive unit 8 controls the color of the display screen based on this signal.

  Based on such setting conditions such as age, visual acuity, visual distance, display size, background brightness, room illumination color temperature, etc. By installing it in a display device, it is possible to display images with brightness and color that viewers of each age group find desirable in various brightness environments and color temperature environments. Even when viewed, it is possible to reduce the fatigue of the viewer. In addition, power consumption can be reduced by reducing the brightness of the screen.

Embodiment 3 FIG.

  The brightness that young people and elderly people find desirable is generally different. For example, the optimum visual constant α value is about α = 0.31 to 0.43 for young people and α = 0.26 to 0.35 for elderly people. It is also possible to obtain a fixed value for each age. In general, by using the respective intermediate values, it is possible to facilitate the calculation and reduce the memory.

  By setting the visual constant α to a fixed value, the calculation of the visual constant calculation unit 11 can be facilitated, and the visual constant calculation unit 11 can be deleted.

  The value of the viewing angle constant β is normally set to 1, so that the calculation can be facilitated and the memory can be reduced. Also, by making β lower than 1, the color temperature can always be set higher with respect to the display luminance, and by making it higher than 1, the color temperature can always be set lower.

The value of the environmental color temperature constant _CE corresponding to the color temperature is experimentally found to be appropriate when a preferable color temperature is calculated by applying usually 1000 or more.

It is a block diagram which shows the image display apparatus which concerns on Embodiment 1 of this invention. It is a graph showing the result of the subjective evaluation experiment which calculated | required the relationship between preferable brightness | luminance and preferred color temperature. It is a block diagram which shows the image display apparatus which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screen illumination intensity measurement part 2 Setting condition input part 3 Background luminance calculation part 4 Memory | storage part 5 Brightness adjustment constant calculation part 6 Brightness sensation luminance calculation part 7 Screen brightness control part
DESCRIPTION OF SYMBOLS 8 Display panel drive part 9 Video signal brightness | luminance calculating part 10 Display screen 11 Visual information calculating part 12 Video signal analyzing part 13 Visual angle constant calculating part 14 Imaging part 20 Color correction calculating part 21 Screen color correction control part 22 Video signal chromaticity calculating part 31 Visual environment color temperature calculation unit

Claims (7)

A display screen;
A screen illuminance measurement unit for measuring the illuminance in the vicinity of the display screen;
A setting condition input section for setting information of the viewer;
Based on the illumination intensity near the display screen and the information and viewing distance of the viewer, a calculation unit for obtaining the brightness of the display screen that the viewer feels preferable,
A screen brightness control unit that determines the maximum brightness of the display screen based on the brightness of the display screen that the viewer feels preferable;
A screen color correction control unit that determines the color of the display screen based on the brightness of the display screen that the viewer feels preferable;
A display panel driving unit that drives the display panel so that the maximum luminance and color correction of the display screen are equal to the maximum luminance and chromaticity determined by the screen luminance control unit and the screen color correction control unit. An image display device characterized by the above.   The image display apparatus according to claim 1, wherein the information on the viewer includes an age of the viewer.   The image display apparatus according to claim 1, wherein the information of the viewer includes a visual acuity of the viewer.   The image display apparatus according to claim 1, wherein the information on the viewer includes a viewing distance of the viewer.   5. The image display device according to claim 1, wherein the color determined by the screen color correction control unit is set by a maximum luminance input by the setting condition input unit. 6. .   The image display device according to claim 1, wherein a color temperature of a viewing environment is calculated based on information obtained from the screen illuminance measurement unit.   The image display device according to claim 1, wherein color correction is performed based on color temperature information of the viewing environment.

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