JP2009031554A - Video display device and video display method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a video display device and a video display method thereof which allow a user to view a video free from a feeling out of place for user's vision by automatically adjusting color temperature so as to correspond to the luminance of a display unit. <P>SOLUTION: The video display device capable of adjusting the luminance and color temperature of the display unit showing the brightness of the screen of the display unit is equipped with an illuminance sensor 6 measuring ambient illuminance and outputting a signal in accordance with the illuminance, and is equipped with a luminance determination part 26 determining the luminance of the display unit from the illuminance measured by the illuminance sensor 6, a color temperature gradation curve correction part 28 correcting a gradation curve for adjusting the RGB gradation of a video signal from the determined luminance and setting it as a gradation correction curve, and a color temperature adjusting means inputting the RGB gradation of the video signal and outputting the RGB gradation converted by a functional expression showing the gradation correction curve to a liquid crystal panel driving part 17. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a video display device and a video display method thereof, and more particularly to a video display device capable of adjusting a color temperature, which is a display color of a video, according to the brightness of the screen when the video is displayed, and the video display method thereof. Is.

  Conventionally, when watching a broadcast program on a television device, the brightness of the display screen is adjusted according to the ambient brightness or the color temperature of the display screen is adjusted according to the ambient color temperature. Things are known. For example, in the invention disclosed in Patent Document 1, a sensor for detecting ambient brightness is provided, and the brightness of the backlight of the liquid crystal panel is adjusted according to the ambient brightness and the video display mode, thereby realizing easy-to-view video display. I was trying to do it. In the invention disclosed in Patent Document 2, the surrounding color temperature is measured, and the display is adjusted at the optimum color temperature for the measured color temperature, so that an easy-to-see video display is realized.

JP 2006-11366 A JP 2003-78920 A

However, in the prior art described in Patent Document 1, the brightness of the screen of the display is automatically adjusted, but the color temperature of the screen is not adjusted. For this reason, although the lighting environment is dark and the brightness of the screen of the display device is dark, the color temperature of the screen may remain high, which is uncomfortable. On the contrary, the color temperature of the screen may remain low despite the fact that the lighting environment is bright and the screen of the display is bright.
In the prior art described in Patent Document 2, the color temperature of the display screen is automatically adjusted, but the brightness of the display screen is not adjusted. For this reason, although the illumination environment is dark and the color temperature of the screen of the display device is low, the brightness of the screen of the display device may remain high, which is uncomfortable. On the other hand, the brightness of the display screen remains low despite the fact that the lighting environment is bright and the color temperature of the display screen is high.

  An object of the present invention is to automatically adjust the color temperature of the screen displayed on the display based on the brightness of the screen of the display, and to allow the user to view a video that does not feel uncomfortable for the user. It is an object to provide a video display device and a video display method thereof.

The video display device of the present invention is a video display device capable of adjusting the brightness and color temperature of the screen of the display,
Brightness adjusting means for adjusting the brightness of the display screen;
Color temperature adjusting means for adjusting the color temperature of the display so that the color temperature is high when the screen brightness of the display is high and the color temperature is low when the screen brightness is low;
It is characterized by having.
In addition, it has an illuminance sensor that detects and outputs ambient illuminance,
The brightness adjusting means includes
The brightness of the screen of the display is determined from the illuminance detected by the illuminance sensor.
Further, the brightness adjusting means includes
When the illuminance detected by the illuminance sensor is high, the storage device stores an illuminance / luminance conversion table in which the illuminance and the luminance of the display screen are set so that the luminance is high when the illuminance is low and the luminance is low when the illuminance is low,
The brightness of the screen of the display is determined with reference to the illuminance / luminance conversion table.
Further, the brightness adjusting means includes
The brightness of the screen of the display is determined from the video position set by the user.
Further, the brightness adjusting means includes
A video position luminance conversion table in which the luminance of the video position and the display screen is set so that the luminance is increased when the video of the video position set by the user is bright and the luminance is decreased when the video position is dark. Storage means for storing,
The screen brightness of the display is determined with reference to the video position brightness conversion table.
In addition, it has an illuminance sensor that detects and outputs ambient illuminance,
The brightness adjusting means includes
The brightness of the screen of the display is determined from the illuminance detected by the illuminance sensor and the video position.
Further, the brightness adjusting means includes
When the illuminance detected by the illuminance sensor is high and the image at the video position is bright, the brightness of the screen of the display is increased, and when the illuminance detected by the illuminance sensor is low and the image at the video position is dark, the Storage means for storing an illuminance video position luminance conversion table set in association with the illuminance range detected by the illuminance sensor, the video position, and the luminance of the display screen so as to lower the luminance of the display screen. Prepared,
The brightness of the screen of the display is determined with reference to the illuminance video position brightness conversion table.
Further, the color temperature adjusting means includes
The color temperature of the screen of the display is adjusted by changing the gradation curve in which the correspondence between the brightness of the screen of the display and the RGB gradation of the video signal is set.
Further, the color temperature adjusting means includes
A function expression of a gradation correction curve for correcting the gradation curve so that the color temperature is increased when the screen brightness of the display is high and the color temperature is decreased when the screen brightness of the display is low. Storage means for storing the set luminance function formula conversion table;
The gradation correction curve is determined with reference to the luminance function formula conversion table.
Further, the color temperature adjusting means includes
Storage means for storing a gradation correction table in which a relation between input data and output data is set by a functional expression representing the gradation curve;
The gradation correction table stored in the storage means is
The function formula is changed so that the relationship between input data and output data changes according to the brightness of the screen of the display.
Further, the color temperature adjusting means includes
The RGB correction of the video signal is corrected with reference to the gradation correction table, and the corrected video signal is output to a display.
The indicator is
LCD panel that can adjust the color temperature of the screen,
A backlight with adjustable screen brightness,
It is characterized by having.
Also, an image display method capable of adjusting the brightness and color temperature of the display screen,
A luminance adjustment step of adjusting the luminance of the screen of the display;
A color temperature adjusting step of adjusting the color temperature of the display screen so that the color temperature is high when the display screen brightness is high and the color temperature is low when the display screen brightness is low; ,
It is characterized by having.

According to the present invention, the brightness of the display screen can be automatically adjusted according to the ambient illuminance, and the color temperature of the screen displayed on the display can be automatically adjusted based on the brightness of the display screen. Therefore, it is possible to automatically adjust the color temperature according to the ambient illuminance and the brightness of the display screen.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a functional block diagram showing the main configuration of the video display apparatus according to the first embodiment of the present invention. This video display device adjusts the RGB gradation of the video signal by converting it with a gradation curve that adjusts the RGB gradation of the received video signal. The display unit is composed of a liquid crystal panel and a backlight. The display unit outputs a video signal adjusted for RGB gradation to the liquid crystal panel, and the brightness adjusted by the illuminance measured by the illuminance sensor is used as the backlight. Output to the inverter controller.
According to the first embodiment of the present invention, in the above video display device, the backlight luminance is determined according to the illuminance measured by the illuminance sensor, and the color of the liquid crystal panel is changed with the RGB gradation having the color temperature according to the backlight luminance. This is an embodiment in which the color temperature of the screen is automatically adjusted by adjusting. The brightness of the screen of the display in the first embodiment corresponds to the brightness of the backlight.

The video display device 1 in FIG. 1 outputs a video signal received by an antenna 2 that is a device that receives broadcast signals from broadcast radio waves or a video signal of the external device 7 received from the communication interface unit 23 to the liquid crystal panel 3. Further, the video display device 1 can input an operation set by the user from the remote controller 5.
The video display device 1 is connected to an illuminance sensor 6 that measures ambient illuminance, and outputs a luminance signal of a screen corresponding to the illuminance measured by the illuminance sensor 6 to the backlight 4.

  Hereinafter, the configuration of the video display device 1 of FIG. 1 will be described.

  The tuner 11 selects and demodulates broadcast radio waves including data of a desired broadcast program, and transport stream signals (physical signals) multiplexed with video signals, audio signals, control signals, signals subjected to error correction processing, and the like. A TS packet that is a TS signal of the channel is output.

The TS decoder 12 extracts a video signal and an audio signal of a desired broadcast program from the TS packet. The video signal and audio signal extracted by the TS decoder 12 are digital data compressed and encoded by the MPEG-2 compression technique. In FIG. 1, only the video signal output to the video decoder is shown, and other audio signals are not shown.

The video decoder 13 decompresses and decodes the video signal compressed and encoded by the MPEG-2 compression technique input from the TS decoder 12. The video decoder 13 inputs the video signal of the external device 7 from the communication interface unit 23 when being switched to input the video signal from the communication interface unit 23 according to a command from the system controller 19. The video decoder 13 handles the video signal after converting it into the following Y, Cb, and Cr.
Y: represents a luminance signal and screen luminance.
Cb: B-Y color difference signal, B (blue)
Cr: RY color difference signal, R (red)

  The luminance / color difference / gradation conversion unit 14 calculates Y, Cb, and Cr, which are the luminance and color difference of the video signal output from the video decoder 13, for each of R (red), G (green), and B (blue) for each pixel. The image is converted to 256 gradations (RGB gradation of the video signal).

In the gradation correction table 15, as shown in FIG. 2, 256 gradations of the video signal are set for the input gradation x, and the RGB gradation converted by a functional expression representing a predetermined gradation curve for the output gradation y. Set each. While the video display device 1 is adjusting the color temperature, the RGB gradation of the video signal corrected based on the R, G, and B gradation correction curves corresponding to the color temperature is set as the output gradation. .
A backup table is prepared in the gradation correction table 15, and when the color temperature adjustment is completed, the data can be copied from the backup table to the gradation correction table 15 and returned to normal data that is not subjected to the color temperature adjustment.

The gradation correction unit 16 refers to the gradation correction table 15 shown in FIG. 2 and performs correction for converting the RGB gradation of the video signal input from the luminance / color difference gradation conversion unit 14 into the output gradation y. That is, each gradation of the R, G, and B signals of the input video signal is converted into R (red), G (green), and B (blue) according to the input gradation x. For example, when the input gradation x is 2, R (red) = y _r2 , G (green) = y _g2 , and B (blue) = y _b2 are set. Although the input gradation x shown in FIG. 2 is 0 to 255, it is obvious that the present invention is not limited to this.

The liquid crystal panel drive unit 17 receives the R, G, and B tone signals from the tone correction unit 16, and synchronizes the R, G, and B tone signals based on the horizontal and vertical sync signals. Signals are sequentially output to the liquid crystal panel 3.

The backlight inverter control unit 18 controls light emission driving of the backlight 4 according to a command from the system controller 19.

The system controller 19 controls the entire video display device 1. A program executed by the system controller 19 and temporary data during the program operation are stored in the memory 20. The remote control receiving unit 21 receives an operation signal such as start / end of color temperature adjustment set by the user from the remote control 5 and outputs the operation signal to the system controller 19. The illuminance sensor receiving unit 22 receives the illuminance measured by the illuminance sensor 6 and outputs it to the system controller 19. The communication interface unit 23 is an interface for exchanging video signals and audio signals with an external device 7 such as a personal computer or an external storage device (DVD, video device, HDD (hard disk), semiconductor memory, etc.). The system bus 24 connects each part and processes signals and data transferred by the video display device 1.

A configuration for automatically adjusting the color temperature of the screen in the video display device 1 of FIG. 1 will be described below.
The illuminance / luminance conversion table 25 is a table for setting the luminance of the backlight in accordance with the surrounding illuminance range as shown in FIG. In the illuminance / luminance conversion table 25, the illuminance range (lx) is divided such that the illuminance is 0 ≦ l <l ₁ , l ₁ ≦ l <l ₂ ,..., And luminance (cd / m ² ) are set as k ₁ , k ₂ , k ₃ .

The luminance determination unit 26 inputs the illuminance measured by the illuminance sensor 6, and determines the luminance of the backlight with reference to the illuminance luminance conversion table 25 having the configuration shown in FIG.

The brightness function formula conversion table 27 is a table in which a function formula of a tone correction curve obtained by correcting the tone curve according to the brightness range of the backlight with a correction amount according to the color temperature as shown in FIG. 4 is set. is there. The gradation curve is for adjusting the RGB gradation of the video signal, and the gradation curve is expressed by a functional expression. The correction amount of the gradation curve is a correction amount for correcting the gradation curve so as to correspond to the color temperature. Here, the tone curve means a characteristic curve that is not corrected for color temperature, and the tone correction curve means that the tone curve is corrected with the correction amount for each input tone to correspond to the color temperature. To do.
FIG. 5 shows examples of reference gradation curves (shown by dotted lines), gradation curve correction amounts (correction amounts r, g, b), and R, G, B gradation correction curves. FIG. 5 shows an example of a screen with a high color temperature and bluish tint. Shown are gradation correction curves for R, G, and B in which the output gradation is corrected with respect to a predetermined reference gradation curve. As shown in FIG. 5, the correction amounts for the gradation correction curve when the input gradation x = 255 of the gradation correction curves for R, G, and B are r (%), g (%), and b (%). It becomes. As shown in the example of FIG. 5, the higher the color temperature, the smaller the B correction amount and the R correction amount (that is, the proportion of B increases and bluish). Although not shown, on the contrary, the lower the color temperature, the smaller the correction amount of R and the larger the correction amount of B (that is, the proportion of R becomes larger and reddish). ). In this way, for each range of luminance of the backlight, the gradation correction curves for R, G, and B corresponding to the luminance in that range are verified and determined in advance. In the function expression of the gradation correction curve of the luminance function expression conversion table 27 in FIG. 4, gradation correction curves of R, G, and B as shown in FIG. 5 are set corresponding to the luminance range.

The color temperature gradation curve correction unit 28 refers to the luminance function expression conversion table 27 having the configuration shown in FIG. 4 and converts the gradation correction curve of the color temperature corresponding to the backlight luminance to a function expression for R (red). Function expressions f _{1g to} f _ng for f _{1r to} f _nr and G (green) are determined as function expressions f _{1b to} f _nb for B (blue), and the determined function expressions are output to the gradation correction table 15. To do.

  FIG. 6 is a flowchart showing the flow of color temperature adjustment processing in the first embodiment of the present invention. The following description is based on the order of steps shown in the flowchart of FIG.

In the color temperature adjustment that automatically adjusts the color temperature of the screen according to the ambient illuminance, when the power of the video display device is turned on and the user performs a color temperature adjustment start operation from the remote controller 5, the system controller 19 periodically Color temperature adjustment is performed. When the user performs an operation for finishing the color temperature adjustment from the remote controller 5, the system controller 19 copies the data from the backup table of the gradation correction table 15 and executes the color temperature adjustment on the gradation correction table 15. Return to normal data and end the color temperature adjustment.

  When the color temperature adjustment is started, the system controller 19 inputs the illuminance measured by the illuminance sensor 6 from the illuminance sensor receiver 22 and stores the input illuminance in the memory 20 (step A1).

The system controller 19 instructs the luminance determination unit 26 to determine the backlight luminance from the illuminance measured by the illuminance sensor 6. The luminance determination unit 26 extracts the illuminance stored in the memory 20 by the system controller 19 in step A1, checks which illuminance range of the illuminance luminance conversion table 25 shown in FIG. To decide. Next, the luminance determining unit 26 extracts the luminance corresponding to the illuminance range determined in the illuminance / luminance conversion table 25 and stores it in the memory 20. This luminance becomes the luminance of the backlight corresponding to the ambient illuminance (step A2).

Next, the system controller 19 instructs the color temperature gradation curve correction unit 28 to correct the gradation curve for adjusting the RGB gradation of the video signal so as to correspond to the color temperature. The color temperature gradation curve correction unit 28 takes out the backlight luminance determined in step A2 from the memory 20 and checks which luminance range of the luminance function formula conversion table 27 shown in FIG. Determine the corresponding luminance range. Next, the color temperature gradation curve correction unit 28 performs R, G, B of the gradation correction curve of the color temperature corresponding to the luminance range determined in the luminance function formula conversion table 27, for example, S _m−1 ≦ k <S _m. Each function expression f _mr , f _mg , f _mb is taken out (step A3). The R, G, and B function formulas are tone correction curve function equations that change the tone curve shown in FIG. 5 to correspond to the color temperature (step A3).

Next, the color temperature gradation curve correction unit 28 is input to the gradation correction table 15 shown in FIG. 2 with the function formulas f _mr , f _mg , and f _mb for R, G, and B determined in step A3. The gradation x is converted into output gradations y _ri , y _gi , and y _bi as shown below, and the output gradations y _ri , y _gi , and y _bi are converted to R, G, and B in the gradation correction table 15. Output gradations R (red), G (green), and B (blue) are set (step A4).
y _ri = f _mr (x) (x = 0 to 255 , Y _ri : i = 0 to 255)
y _gi = f _mg (x) (x = 0 to 255 , Y _gi : i = 0 to 255)
y _bi = f _mb (x) (x = 0 to 255 , Y _bi : i = 0 to 255)

As described above, in the gradation correction table 15, the R, G, and B gradations corrected based on the respective R, G, and B gradation correction curves corresponding to the color temperature are set as output gradations. The gradation correction unit 16 checks which input gradation of the gradation correction table 15 each of R, G, and B input from the luminance / color difference gradation conversion unit 14 is equal to, and determines an equal input gradation. To do. Output gradations for each of R, G, and B corresponding to the determined input gradation are extracted and output to the liquid crystal panel drive unit 17. The color temperature is adjusted to the luminance of the liquid crystal panel 3 corresponding to the ambient illuminance by the RGB gradation of the output video signal.

According to the first embodiment, the brightness of the backlight of the liquid crystal panel is adjusted based on the ambient illuminance, and the color temperature of the screen displayed on the liquid crystal panel is automatically adjusted based on the brightness of the backlight. Can be adjusted. Accordingly, it is possible to provide a video display apparatus and a video display method for automatically adjusting the color temperature to match the ambient brightness without any sense of discomfort to the user's vision.

(Second Embodiment)
The functional block diagram of the video display device of the second embodiment is the same as the functional block diagram of the video display device of FIG. 1 according to the first embodiment, but the illuminance / luminance conversion table 25 is changed to the video position / luminance conversion table 29. The changes are different. Except for this changed part, the function block diagram is the same as that of the first embodiment in FIG. 1, and the parts not related to the video position luminance conversion table 29 are the same as those described in the function block diagram of the first embodiment. is there.

  In the second embodiment of the present invention, the backlight brightness is determined according to the video position set by the user from the remote control, and the liquid crystal panel is adjusted with the RGB gradation having the color temperature according to the backlight brightness. This is an embodiment for automatically adjusting the color temperature of the screen. The video position refers to R, G, and B gradations set according to user preference, and can be arbitrarily set by the user with a video position button or the like provided on the remote controller.

The video position luminance conversion table 29 of the video display device of the second embodiment is a table in which the luminance of the backlight is set according to the video position set by the user having the configuration shown in FIG. In the second embodiment, the luminance determining unit 26 inputs the video position set by the user from the remote controller, and determines the luminance of the backlight with reference to the video position luminance conversion table 29 having the configuration shown in FIG. The main video types of video positions are shown below.

Video position Video type
1: Standard (image quality and sound quality are standard values)
2: Movie (video with reduced contrast)
3: Game (video that is easy on the eyes with reduced brightness)
4: PC (screen mode for PC)

  FIG. 8 is a flowchart showing the flow of color temperature adjustment processing in the second embodiment of the present invention. FIG. 8 is the same as the flowchart of the first embodiment except that step A1 in FIG. 6 is changed to step B1, and step A2 is changed to step B2. Therefore, step B1 and step B2 will be described below. Step A3 and step A4 shown in the flowchart of FIG. 8 are the same as those in the flowchart of the first embodiment.

The color temperature adjustment for automatically adjusting the color temperature of the screen according to the video position is started when the video display device is turned on and the user sets the button of the corresponding video position on the remote controller 5. When the video position is set during the color temperature adjustment, the system controller 19 executes the color temperature adjustment at a constant period, and the gradation correction table 15 is corrected so as to correspond to the color temperature. When the user performs an operation for finishing the color temperature adjustment from the remote controller 5, the system controller 19 copies the data from the backup table of the gradation correction table 15 and executes the color temperature adjustment on the gradation correction table 15. Return to normal data and end the color temperature adjustment.

  When the color temperature adjustment start operation and the video position are set, the system controller 19 inputs the video position data from the remote control receiver 21, and stores the input video position data in the memory 20 (step B1).

The system controller 19 issues a command for determining the backlight luminance from the video position to the luminance determining unit 26. The luminance determination unit 26 extracts the video position data stored in the memory 20 by the system controller 19 in step B1, and checks which video position in the video position luminance conversion table 29 shown in FIG. To do. Then, the luminance corresponding to the same video position is extracted from the video position luminance conversion table 29 and stored in the memory 20. This luminance becomes the luminance of the backlight corresponding to the video position (step B2).
The process of determining the tone correction curve function formula corresponding to the color temperature from the backlight luminance performed in step A3 of the flowchart of FIG. 8 and the tone correction curve function formula performed in step A4 correct the RGB tone. The processing is the same as in the first embodiment.

  According to the second embodiment, the brightness of the backlight of the liquid crystal panel is adjusted based on the video position set by the user, and the color temperature of the screen displayed on the liquid crystal panel is further based on the brightness of the backlight. It is possible to provide a video display device and a video display method for automatically adjusting the video.

(Third embodiment)
The third embodiment of the present invention determines the backlight luminance according to both the illuminance measured by the illuminance sensor and the video position set by the user from the remote control, and the RGB gradation that provides the color temperature according to the backlight luminance. In this embodiment, the color temperature of the screen is automatically adjusted by adjusting the hue of the liquid crystal panel.

  The functional block diagram of the video display device of the third embodiment is the same as the functional block diagram of the video display device of FIG. 1 according to the first embodiment, but the illuminance / luminance conversion table 25 is changed to the illuminance / video position / luminance conversion table. The point of changing to 30 is different. Except for this change, it is the same as the functional block diagram of the first embodiment of FIG.

In the illuminance video position luminance conversion table 30 of the video display device of the third embodiment, the illuminance measured by the illuminance sensor and the luminance of the backlight corresponding to the video position set by the user are set as shown in FIG. It is a table. In the third embodiment, the luminance determination unit 26 inputs the illuminance measured by the illuminance sensor and the video position set by the user from the remote controller, and refers to the illuminance video position luminance conversion table 30 having the configuration shown in FIG. Determine the brightness.

  Regarding the flowchart of color temperature adjustment in the third embodiment of the present invention, step A1 of FIG. 6 which is the flowchart of the first embodiment and step B1 of FIG. 8 which is the flowchart of the second embodiment are performed. The screen color temperature is changed so as to determine the luminance from the illuminance measured by the illuminance sensor and the video position set by the user from the remote control. The subsequent processing is the same as the processing for correcting the RGB gradation using the functional expression of the gradation correction curve corresponding to the color temperature from the backlight luminance performed in step A3 and subsequent steps in the flowchart of the first embodiment.

  Although described in the first to third embodiments of the present invention, the function expression of the gradation correction curve may be an arithmetic expression, and the function expression is expressed by a table corresponding to input and output. It may be.

  The present invention is suitable for a video display device and a video display method thereof, but is not limited to a video display device and a video display method thereof.

1 is a functional block diagram of a video display apparatus according to a first embodiment of the present invention. Configuration diagram showing an example of a gradation correction table Configuration diagram showing an example of illuminance / luminance conversion table Configuration diagram showing an example of a luminance function formula conversion table Diagram showing an example of the tone correction curve Flow chart showing the process of automatically adjusting the color temperature of the screen The block diagram which shows an example of the video position brightness | luminance conversion table in the 2nd Embodiment of this invention. Flow chart showing the process of automatically adjusting the color temperature of the screen Illuminance video position luminance conversion table in the third embodiment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Video display device 2 ... Antenna 3 ... Liquid crystal panel 4 ... Backlight 5 ... Remote control 6 ... Illuminance sensor 7 ... External device 11 ・ Tuner 12 ・ ・ TS decoder 13.. Video decoder 14 .. Luminance color difference gradation conversion unit 15 .. Gradation correction table 16 .. Gradation correction unit 17 .. Liquid crystal panel drive unit 18 .. Backlight inverter control unit 19 .. System controller 20. -Memory 21-Remote control receiver 22-Illuminance sensor receiver 23-Communication interface unit 24-System bus 25-Illuminance luminance conversion table 26-Luminance determination unit 27-Luminance function formula conversion table 28- Color temperature gradation curve correction unit 29 .. Video position luminance conversion table 30 .. Illuminance video position luminance conversion table

Claims (13)

A video display device capable of adjusting the brightness and color temperature of the display screen,
Brightness adjusting means for adjusting the brightness of the display screen;
Color temperature adjusting means for adjusting the color temperature of the display so that the color temperature is high when the screen brightness of the display is high and the color temperature is low when the screen brightness is low;
A video display device comprising: It has an illuminance sensor that detects and outputs ambient illuminance,
The brightness adjusting means includes
The video display device according to claim 1, wherein brightness of a screen of the display is determined from illuminance detected by the illuminance sensor. The brightness adjusting means includes
When the illuminance detected by the illuminance sensor is high, the storage device stores an illuminance / luminance conversion table in which the illuminance and the luminance of the display screen are set so that the luminance is high when the illuminance is low and the luminance is low when the illuminance is low,
The video display device according to claim 2, wherein the brightness of the screen of the display is determined with reference to the illuminance / luminance conversion table. The brightness adjusting means includes
The video display device according to claim 1, wherein the brightness of the screen of the display device is determined from a video position where a user sets a video type. The brightness adjusting means includes
A video position luminance conversion table in which the luminance of the video position and the display screen is set so that the luminance is increased when the video of the video position set by the user is bright and the luminance is decreased when the video position is dark. Storage means for storing,
The video display device according to claim 4, wherein the luminance of the screen of the display is determined with reference to the video position luminance conversion table. It has an illuminance sensor that detects and outputs ambient illuminance,
The brightness adjusting means includes
The video display device according to claim 4, wherein the brightness of the screen of the display is determined from the illuminance detected by the illuminance sensor and the video position. The brightness adjusting means includes
When the illuminance detected by the illuminance sensor is high and the image at the video position is bright, the brightness of the screen of the display is increased, and when the illuminance detected by the illuminance sensor is low and the image at the video position is dark, the Storage means for storing an illuminance video position luminance conversion table set in association with the illuminance range detected by the illuminance sensor, the video position, and the luminance of the display screen so as to lower the luminance of the display screen. Prepared,
The video display device according to claim 6, wherein the luminance of the screen of the display is determined with reference to the illuminance video position luminance conversion table. The color temperature adjusting means is
The color temperature of the screen of the display is adjusted by changing a gradation curve in which the correspondence between the brightness of the screen of the display and the RGB gradation of the video signal is set. The video display device according to claim 7. The color temperature adjusting means is
A function expression of a gradation correction curve for correcting the gradation curve so that the color temperature is increased when the screen brightness of the display is high and the color temperature is decreased when the screen brightness of the display is low. Storage means for storing the set luminance function formula conversion table;
9. The video display device according to claim 8, wherein the gradation correction curve is determined with reference to the luminance function formula conversion table. The color temperature adjusting means is
Storage means for storing a gradation correction table in which a relation between input data and output data is set by a functional expression representing the gradation curve;
The gradation correction table stored in the storage means is
The video display device according to claim 8 or 9, wherein the function expression is changed so that a relationship between input data and output data changes according to a luminance of a screen of the display. The color temperature adjusting means is
11. The video display apparatus according to claim 10, wherein the gradation correction table is referenced to correct the RGB gradation of the video signal, and the corrected video signal is output to a display device. The indicator is
LCD panel that can adjust the color temperature of the screen,
A backlight with adjustable screen brightness,
The video display device according to claim 1, further comprising: An image display method capable of adjusting the brightness and color temperature of the display screen,
A luminance adjustment step of adjusting the luminance of the screen of the display;
A color temperature adjusting step of adjusting the color temperature of the display screen so that the color temperature is high when the display screen brightness is high and the color temperature is low when the display screen brightness is low; ,
A video display method characterized by comprising:

Images