JP2007012534A - Light source control device, color display device, and color display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source control device, a color display device, and a color display method, capable of adjusting brightness of light irradiated from a light source, if color temperature is changed. <P>SOLUTION: The color display device, a liquid crystal display 10 changing color temperature by changing color temperature data, is provided with a backlight 15, a control part 13 for controlling the backlight 15, and a storage part 14 for storing the color temperature data. The control part 13 is provided with a data acquisition part 16 for acquiring color temperature data coordinated to color temperature after changing, and brightness data coordinated to the color temperature data from the storing part 14, and a brightness control part 18 for adjusting brightness of light irradiated from the backlight based on the brightness data. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source control device, a color display device, and a color display method for controlling a light source according to a change in color temperature.

  Conventionally, as a method of adjusting the color temperature, there is a method of changing the color temperature by breaking the RGB color balance. In this method, for example, in the NTSC color system (color temperature 6500K), when the conversion represented by the following formula (1) is generally established in the RGB color system and the XYZ coordinate system, white (x, y) = 6500K = The ratio of RGB when displaying (0.3101, 0.3162) is obtained as approximately R: G: B = 1: 1: 1 from the equations (1) and (2).

z = 1-xy (2)
In the case of displaying 9300K white (x, y) = (0.283, 0.297) in this color system, R: G: B = 0.729: 0.845 is similarly obtained from the equation (1). : 1 is obtained. That is, by setting the ratio of RGB to the above ratio, a color temperature of 9300K can be obtained. Thus, various color temperatures can be obtained by changing the ratio of RGB.

For example, when the color temperature is converted in the liquid crystal display device, the RGB ratio (coefficient) corresponding to the color temperature after conversion is obtained in advance, and the coefficient corresponding to the selected color temperature is used. The color temperature is converted. However, the luminance may change as the color temperature is converted. On the other hand, a backlight control device that maintains stable brightness is disclosed (for example, see Patent Document 1).
Japanese Unexamined Patent Publication No. 2000-250008 (published on September 14, 2000)

  However, the backlight control device of Patent Document 1 includes a detection unit that detects the luminance of light emitted from the backlight, and the luminance is actually measured by the detection unit. And based on the brightness | luminance measured by the detection means, it controls so that the brightness | luminance of the light irradiated from a backlight may become predetermined brightness | luminance.

  That is, in the configuration of Patent Document 1, it is necessary to provide a detection means for detecting the luminance, which has a problem that the apparatus becomes complicated and large, and the cost increases. Further, the backlight control device of Patent Document 1 corrects variations in luminance due to changes in backlight luminance by the user, ambient temperature, and changes over time of lamps used in the backlight. is there. Therefore, it does not correct the luminance that changes with the control of the color temperature.

  The present invention has been made in view of the above problems, and its purpose is to emit light from a light source without providing a means for detecting luminance even when the color temperature is changed. It is to realize a light source control device, a color display device, and a color display method capable of adjusting the luminance of the light.

  In order to solve the above problems, a light source control device according to the present invention is a light source control device that includes a light source and is used in a color display device that changes a color temperature based on color temperature information, and controls the light source. An acquisition means for acquiring the color temperature information and a luminance correction value associated with the color temperature information and correcting the luminance of the light emitted from the light source; from the light source based on the luminance correction value; And a luminance adjusting means for adjusting the luminance of the emitted light.

  According to said structure, a color display apparatus changes the color temperature to display based on color temperature information, and a light source control apparatus controls the light source with which this color display apparatus is provided. The color temperature information is information for expressing the color temperature, and is information regarding the ratio of a plurality of color components. Examples of the plurality of color components include RGB.

  Further, by providing the acquisition means, it is possible to acquire color temperature information associated with the color temperature and a luminance correction value associated with the color temperature information. The brightness correction value is data for correcting the brightness of light emitted from the light source. Further, by providing the brightness adjusting means, the brightness of the light emitted from the light source can be adjusted based on the acquired brightness correction value.

  That is, when the color temperature is changed, the color temperature information of the color temperature after the change and the luminance correction value associated with the color temperature information can be acquired, and the luminance is corrected based on the luminance correction value. Since the adjustment is performed, the adjustment based on the color temperature after the change can be performed.

  Specifically, even when the color display device changes the color temperature, the light source is adjusted based on the changed color temperature, and the brightness of the screen changes before and after the change of the color temperature. Can be improved. In particular, it is possible to improve a decrease in luminance associated with a change in color temperature.

  In order to solve the above problems, a light source control device according to the present invention is a light source control device that includes a light source and is used in a color display device that changes a color temperature based on color temperature information, and controls the light source. An acquisition means for acquiring the color temperature information, a brightness correction value generation means for generating a brightness correction value for correcting the brightness of light emitted from the light source based on the color temperature information, and the brightness correction. And a luminance adjusting means for adjusting the luminance of the light emitted from the light source based on the value.

  According to said structure, a color display apparatus changes the color temperature to display based on color temperature information, and a light source control apparatus controls the light source with which this color display apparatus is provided.

  In addition, by providing the acquisition unit, the color temperature information associated with the color temperature can be acquired. Furthermore, by providing the luminance correction value generation means, it is possible to generate a luminance correction value for correcting the luminance of the light emitted from the light source based on the acquired color temperature information.

  That is, when the color temperature is changed, the brightness correction value can be generated only by acquiring the color temperature information of the color temperature after the change, and the brightness is adjusted based on the brightness correction value. The adjustment based on the color temperature after the change can be performed.

  Specifically, even when the color display device changes the color temperature, the light source is adjusted based on the changed color temperature, and the brightness of the screen changes before and after the change of the color temperature. Can be improved. In particular, it is possible to improve a decrease in luminance associated with a change in color temperature.

  In the light source control device according to the present invention, the brightness adjusting unit weights the brightness correction value associated with the changed color temperature to the value indicating the brightness associated with the changed color temperature. It is preferable. According to the above configuration, when the color temperature is changed, the luminance of the light emitted from the light source is not the luminance associated with the changed color temperature, but the luminance weighted with the luminance correction value. The light source can be adjusted as follows. That is, it becomes possible to adjust the light source based on the color temperature after the change, and it is possible to improve the luminance decrease due to the change in the color temperature.

  In the light source control device according to the present invention, the brightness correction value is a coefficient calculated based on the brightness associated with the reference color temperature and the brightness associated with the changed color temperature. Is preferred. According to the above configuration, the luminance correction value can be a uniquely determined coefficient associated with the color temperature. The reference color temperature is, for example, a color temperature for calculating color temperature information or a luminance correction value. In this case, the color temperature information and the luminance correction value can be calculated based on the color temperature information and the luminance associated with the reference color temperature. Therefore, the light source can be adjusted based on the color temperature after the change.

  In order to solve the above problems, a color display device according to the present invention is a color display device that changes a color temperature based on color temperature information, and includes a light source, a light source control unit that controls the light source, and the color. Temperature information, and a storage device that stores a brightness correction value that is associated with the color temperature information and corrects the brightness of light emitted from the light source, and the light source control means includes: An acquisition unit that acquires a luminance correction value associated with the color temperature after the change, and a luminance adjustment unit that adjusts the luminance of the light emitted from the light source based on the luminance correction value acquired by the acquisition unit. It is characterized by having.

  According to said structure, a color display apparatus changes the color temperature to display based on color temperature information. In addition, the storage device stores color temperature information and a luminance correction value associated with the color temperature information.

  The color temperature information is information for expressing the color temperature, and is information regarding the ratio of a plurality of color components. The luminance correction value is data for correcting the luminance of light emitted from the light source. Examples of the plurality of color components include RGB.

  The light source control means includes an acquisition means and a brightness adjustment means. The acquisition unit acquires the color temperature information and the luminance correction value associated with the color temperature information from the storage device, and adjusts the luminance of the light emitted from the light source based on the luminance correction value acquired by the luminance adjustment unit. To do.

  As described above, when the color temperature is changed, the color temperature information associated with each color temperature and the luminance correction value associated with the color temperature information, which are stored in the storage device in advance, are acquired. Since the luminance is adjusted based on the luminance correction value, the luminance of the light emitted from the light source can be adjusted based on the changed color temperature.

  Therefore, even when the color temperature is changed, the brightness of the light source is adjusted based on the color temperature after the change, and it is improved that the brightness of the screen changes before and after the change of the color temperature. it can. In particular, it is possible to improve a decrease in luminance associated with a change in color temperature.

  Further, unlike the conventional configuration, it is not necessary to provide a means for detecting luminance such as a luminance detecting means, and the light source is controlled using a luminance correction value calculated in advance based on the color temperature information. Both the change of the color temperature and the adjustment of the luminance of the light emitted from the light source can be realized at low cost.

  In order to solve the above problems, a color display device according to the present invention is a color display device that changes a color temperature based on color temperature information, and includes a light source, a light source control unit that controls the light source, and the color. A storage device storing temperature information, wherein the light source control means acquires from the storage device color temperature information associated with the changed color temperature, and the color temperature acquired by the acquisition means. Based on the information, brightness correction value generating means for generating a brightness correction value for correcting the brightness of the light emitted from the light source, and adjusting the brightness of the light emitted from the light source based on the brightness correction value. And a luminance adjusting means.

  According to said structure, a color display apparatus changes the color temperature to display based on color temperature information. The storage device stores color temperature information. The color temperature information is information for expressing the color temperature, and is information regarding the ratio of a plurality of color components. Examples of the plurality of color components include RGB.

  The light source control unit includes an acquisition unit, a luminance correction value generation unit, and a luminance adjustment unit. The acquisition unit acquires color temperature information from the storage device, and the luminance correction value generation unit generates a luminance correction value based on the color temperature information. And the brightness | luminance of the light radiate | emitted from a light source is adjusted based on this brightness | luminance correction value. The luminance correction value is data for correcting the luminance of light emitted from the light source.

  As described above, when the color temperature is changed, the color temperature information associated with each color temperature, which is stored in advance in the storage device, is acquired, and based on the luminance correction value generated using the color temperature information. Therefore, the brightness of the light emitted from the light source can be adjusted based on the color temperature after the change.

  Therefore, even when the color temperature is changed, the brightness of the light source is adjusted based on the color temperature after the change, and it is improved that the brightness of the screen changes before and after the change of the color temperature. it can. In particular, it is possible to improve a decrease in luminance associated with a change in color temperature.

  Further, it is possible to adjust the color temperature and adjust the luminance based on the color temperature information, and it is possible to easily perform these controls. In addition, a luminance correction value is created by predicting appropriate luminance from the color temperature information, and the light source control at the time of changing the color temperature can be realized at low cost.

  The color display device according to the present invention further includes color temperature changing means for changing the color temperature to be displayed based on the color temperature information associated with the color temperature after change obtained by the obtaining means. Is preferred.

  According to said structure, since it is based on the color temperature information matched with the color temperature after a change, the color temperature to display can be changed easily.

  In the color display device according to the present invention, the brightness adjusting unit weights the brightness correction value associated with the changed color temperature to the value indicating the brightness associated with the changed color temperature. It is preferable. According to the above configuration, when the color temperature is changed, the luminance of the light emitted from the light source is not the luminance associated with the changed color temperature, but the luminance weighted with the luminance correction value. The light source can be adjusted as follows. That is, it becomes possible to adjust the light source based on the color temperature after the change, and it is possible to improve the luminance decrease due to the change in the color temperature.

  In the color display device according to the present invention, the luminance correction value is a coefficient calculated based on the luminance associated with the reference color temperature and the luminance associated with the changed color temperature. Is preferred. According to the above configuration, the luminance correction value can be a uniquely determined coefficient associated with the color temperature. Therefore, the light source can be adjusted based on the color temperature after the change.

  In order to solve the above problems, the color display method according to the present invention is a color display method for emitting light from a light source and changing the color temperature based on the color temperature information, corresponding to the changed color temperature. The attached color temperature information and a luminance correction value for correcting the luminance of the light emitted from the light source, which is associated with the color temperature information, are acquired, and are emitted from the light source based on the luminance correction value. It is characterized by adjusting the brightness of light.

  According to the above configuration, the color display method emits light from the light source and changes the color temperature based on the color temperature information. Also, the color temperature information associated with the color temperature after the change and the luminance correction value associated with the color temperature information are acquired, and the luminance of the light emitted from the light source is calculated based on the luminance correction value. To be adjusted.

  The color temperature information is information for expressing the color temperature, and is information regarding the ratio of a plurality of color components. The luminance correction value is data for correcting the luminance of light emitted from the light source. Examples of the plurality of color components include RGB.

  That is, the color temperature information and the brightness correction value are acquired, and the brightness of the light emitted from the light source is adjusted based on the brightness correction value. Therefore, even when the color temperature is changed, the brightness of the light source is adjusted based on the color temperature after the change, and it is improved that the brightness of the screen changes before and after the change of the color temperature. it can. In particular, it is possible to improve a decrease in luminance associated with a change in color temperature.

  In order to solve the above problems, the color display method according to the present invention is a color display method for emitting light from a light source and changing the color temperature based on the color temperature information, corresponding to the changed color temperature. The attached color temperature information is acquired, and based on the acquired color temperature information, a luminance correction value for correcting the luminance of the light emitted from the light source is generated, and from the light source based on the luminance correction value The brightness of the emitted light is adjusted.

  According to the above configuration, the color display method emits light from the light source and changes the color temperature based on the color temperature information. Also, the color temperature information associated with the color temperature after the change is acquired, the brightness correction value associated with the color temperature information is generated, and the brightness of the light emitted from the light source based on the brightness correction value Is to adjust.

  The color temperature information is information for expressing the color temperature, and is information regarding the ratio of a plurality of color components. The luminance correction value is data for correcting the luminance of light emitted from the light source. Examples of the plurality of color components include RGB.

  Further, according to the above configuration, the brightness correction value is generated based on the acquired color temperature information, and the brightness of the light emitted from the light source is adjusted based on the brightness correction value. It is possible to adjust the change of the color temperature and the luminance of the light source, and each of these controls can be easily performed.

  That is, the color temperature information is acquired, and the brightness of light emitted from the light source is adjusted based on the brightness correction value generated using the color temperature information. Therefore, even when the color temperature is changed, the brightness of the light source is adjusted based on the color temperature after the change, and it is improved that the brightness of the screen changes before and after the change of the color temperature. it can. In particular, it is possible to improve a decrease in luminance associated with a change in color temperature.

  In the color display method according to the present invention, it is preferable to weight the luminance correction value associated with the color temperature after the change with respect to the value indicating the luminance associated with the color temperature after the change. According to the above configuration, when the color temperature is changed, the luminance of the light emitted from the light source is not the luminance associated with the changed color temperature, but the luminance weighted with the luminance correction value. The light source can be adjusted as follows. That is, it becomes possible to adjust the light source based on the color temperature after the change, and it is possible to improve the luminance decrease due to the change in the color temperature.

  As described above, the light source control device according to the present invention is a light source control device that controls a light source and includes a light source and is used for a color display device that changes a color temperature based on color temperature information. An acquisition unit that acquires color temperature information and a luminance correction value that is associated with the color temperature information and corrects the luminance of light emitted from the light source, and is emitted from the light source based on the luminance correction value. Since the brightness adjusting means for adjusting the brightness of the light is provided, when the color temperature is changed, the brightness can be adjusted based on the changed color temperature.

  The color display device according to the present invention is a color display device that changes the color temperature based on the color temperature information as described above, and includes a light source, a light source control unit that controls the light source, and the color temperature. And a storage device that stores brightness correction values associated with the color temperature information and for correcting the brightness of the light emitted from the light source, and the light source control means changes from the storage device. Acquisition means for acquiring a luminance correction value associated with a later color temperature, and luminance adjustment means for adjusting the luminance of light emitted from the light source based on the luminance correction value acquired by the acquisition means Therefore, there is an effect that it is possible to improve that the luminance of the screen changes before and after the change of the color temperature.

  Further, as described above, the color display method according to the present invention is a color display method that emits light from a light source and changes the color temperature based on the color temperature information, and associates the color temperature with the changed color temperature. The obtained color temperature information and a luminance correction value for correcting the luminance of the light emitted from the light source, which is associated with the color temperature information, are acquired, and emitted from the light source based on the luminance correction value. Since the brightness of the light is adjusted, it is possible to improve that the brightness of the screen changes before and after the change of the color temperature.

[Embodiment 1]
The first embodiment of the present invention will be described below with reference to FIGS.

  In this embodiment, a liquid crystal display device will be described as an example. However, the present invention is not limited to this, and other display devices capable of color display such as CRT and PDP may be used. In addition, examples of the format of video and image display signals include the color television format NTSC format, PAL format, SECAM format, and the like, and any format may be used. Now, a case where the NTSC system is used will be described.

  FIG. 1 is a block diagram showing a schematic configuration of a liquid crystal display device (color display device) 10 according to the present embodiment. As shown in FIG. 1, the liquid crystal display device 10 includes a liquid crystal display panel 11, an input unit 12, a control unit (light source control device, light source control means) 13, and a storage unit (storage device) 14.

  The liquid crystal display panel 11 is a device for displaying video and images, and includes a backlight (light source) 15 as a light source. The liquid crystal display panel 11 includes a liquid crystal display element (not shown) having a large number of TFTs (thin film transistors) for switching the liquid crystal layer, and a source for applying a display signal to the source electrode of each TFT. A driver (not shown) and a gate driver (not shown) for applying a gate voltage (scanning signal) to the gate electrode of each TFT are provided.

  The liquid crystal display panel 11 displays images and images under the control of the control unit 13. That is, the liquid crystal panel 11 displays a predetermined video or image based on a display signal or a scanning signal input from the control unit 13.

  The input unit 12 is for inputting a predetermined signal from the outside. Examples of the predetermined signal include a signal related to a change in the color temperature of an image or image displayed on the liquid crystal display panel 11.

  Further, the input unit 12 can be constituted by, for example, a liquid crystal monitor having buttons for input. That is, in this case, for example, while watching a menu displayed on the liquid crystal monitor, the setting can be changed so that the user can press the button to obtain a desired color temperature. When the color temperature setting is changed, a signal (selection signal) regarding the setting change is sent to the control unit 13.

  The storage unit 14 stores in advance a look-up table (LUT) related to color temperature data (color temperature information) and luminance data (luminance correction value) associated with various color temperatures. Here, the color temperature data is data relating to RGB necessary for irradiating light of a corresponding color temperature from the liquid crystal display panel 11. Specifically, it is a combination of a plurality of color components, and is data indicating coefficients for correcting each RGB value as a reference. The luminance data is data necessary for irradiating light with a corresponding luminance from the backlight 15. Specifically, it is data indicating a coefficient for correcting a value indicating luminance as a reference.

  These color temperature data and luminance data are data associated with each color temperature. Details of the LUT, color temperature data, and luminance data will be described later.

  The control unit 13 controls the entire liquid crystal display device 10. For example, the control unit 13 controls the liquid crystal display panel 11 to display a predetermined video or image at a predetermined color temperature or luminance. The control unit 13 includes a data acquisition unit (acquisition unit) 16, a display control unit (color temperature changing unit) 17, and a luminance control unit (luminance adjustment unit) 18.

  The data acquisition unit 16 acquires color temperature data and luminance data as necessary. When the data acquisition unit 16 receives the color temperature selection signal from the input unit 12, the data acquisition unit 16 refers to the LUT stored in the storage unit 14 and obtains the changed color temperature data and luminance data corresponding to the selection signal. The data acquisition unit 16 outputs the obtained color temperature data to the display control unit 17 and outputs luminance data to the luminance control unit 18.

  In the liquid crystal display device 10 of the present invention, the control unit 13 outputs not only the color temperature data to the display control unit 17 but also the display data related to the video or image to be displayed to the display control unit 17. Alternatively, other means other than the control unit 13 may be configured to output display data to the display control unit 17.

  The display control unit 17 performs control to change the color temperature displayed on the liquid crystal display panel 11 based on the input color temperature data. As a result, the liquid crystal display panel 11 displays a video or image that has been changed to a predetermined color temperature. Details of the method for changing the color temperature based on the color temperature data will be described later.

  The luminance control unit 18 controls the backlight 15 based on the input luminance data. The luminance control unit 18 controls the backlight 15 to adjust the luminance of the light emitted from the backlight 15, and the backlight 15 emits light having a predetermined luminance. Details of the method for controlling the backlight 15 based on the luminance data will be described later.

  Next, the LUT will be specifically described with reference to FIG. FIG. 2 is a diagram illustrating the LUT according to the present embodiment. The LUT is a table that stores settings for identifying each color temperature, and color temperature data and luminance data associated with each color temperature. As described above, the LUT according to the present embodiment is obtained by calculating luminance data in advance and storing it together with the color temperature data. In FIG. 2, for convenience of explanation, only data relating to three types of color temperatures are shown, but the number of data may be set as appropriate and is not limited to this LUT.

  As shown in FIG. 2, data (αa, βa, γa, θa), (αb, βb, γb, θb), (αc, βc, γc, θc) are set for setting A, setting B, setting C,. Are associated with each other.

  Setting A, setting B, setting C,... Are identification data for identifying the color temperature. In the LUT, each setting is associated with color temperature data and luminance data. For example, taking (αa, βa, γa, θa) as an example, αa, βa, and γa are color temperature data corresponding to the setting A, and the displayed color temperatures (R, G, B) are corrected. It is a coefficient to do.

  Here, the color temperature data is a coefficient predetermined for each color temperature (for each setting). That is, the color temperature data is a coefficient uniquely determined for each color temperature. This color temperature data is determined based on the color temperature during white display. For example, assuming that the color temperature when displaying white at 6500K is (R, G, B) and the color temperature when displaying a color is (R ′, G ′, B ′), R ′ = αaR, G ′ = βaG , B ′ = γaB, the coefficients are determined. That is, the color temperature data at the time of displaying a color in the present embodiment is (αa, βa, γa). Note that R: G: B = 1: 1: 1.

  In general, an arbitrary color can be expressed by a mixture of three primary colors, that is, R (red), G (green), and B (blue). Therefore, by setting the addition ratio of the three color components for each color, each color component can be corrected and each color temperature can be expressed.

  Θa is luminance data corresponding to setting A, and is a coefficient for correcting the luminance to correspond to the color temperature to be displayed. That is, the luminance data is also a coefficient determined in advance for each color temperature (for each setting), and is a coefficient uniquely determined for each color temperature. This luminance data is calculated as follows, for example.

A method for calculating luminance data stored in advance in the LUT will be described. In general, in the NTSC system, the relationship between RGB and luminance Y is expressed by the following equation (3):
Y = 0.22989 × R + 0.5866 × G + 0.1145 × B (3)
Can be obtained. That is, for example, the luminance Y corresponding to RGB used in 6500K white display (R: G: B = 1: 1: 1) can be obtained from the above equation (3).

On the other hand, a preferable luminance Y ′ of light emitted from the backlight 15 corresponding to the changed color temperature (color temperature corresponding to the selected setting) is expressed by the following equation (4).
Y ′ = 0.22989 × R ′ + 0.5866 × G ′ + 0.1145 × B ′ (4)
Can be obtained.

  Therefore, the luminance Y of the backlight 15 at the time of white display is obtained from the RGB values used at the time of white display, and the backlight 15 corresponding to the color temperature after the change from the value of R′G′B ′ after the change. The preferred luminance Y ′ can be obtained.

  Further, in the case of changing the color temperature, the relationship between the luminance at the time of white display Y and the luminance Y ′ after the change can be expressed as Y = θY ′ when the luminance data is θ. Therefore, θ = Y / Y ′, and the luminance data θ can be obtained. In the LUT according to the present embodiment, θ is calculated in advance using this equation.

  For example, a case where the color temperature is changed from 6500K (R = 100, G = 100, B = 100) to 9300K (R = 72.9, G = 84.5, B = 100) will be described. The color temperature data used when displaying at a color temperature of 9300K is (0.729, 0.845, 0.1) because of the relationship of R ′ = αaR, G ′ = βaG, and B ′ = γaB. . Further, from the above formulas (3) and (4), the luminance Y = 100 at 6500K and the luminance Y ′ = 82.8 at 9300K. The luminance data θ in this case can be obtained as follows. That is, since θ = Y / Y ′, the luminance data θ is 100 ÷ 82.8 = 1.2.

  Therefore, for example, when the color temperature is changed from the 6500K state to the 9300K state, the display control unit 17 adds predetermined color temperature data (0.729, 0.845, 0.1) is multiplied (weighted). That is, the liquid crystal display panel 11 is controlled so that the display control unit 17 displays at a predetermined color temperature. In addition, the luminance control unit 18 multiplies (weights) a value indicating luminance corresponding to the changed color temperature by θ = 1.2 that is luminance data. That is, the luminance control unit 18 adjusts luminance using luminance data as an argument, and controls the backlight 15 to increase the luminance of light emitted from the backlight 15 after changing the color temperature by 1.2 times. Thereby, the brightness | luminance of the backlight 15 can be adjusted, the brightness | luminance difference before and behind color temperature conversion can be minimized, and the brightness | luminance fall accompanying the change of color temperature can be improved.

  In this embodiment, the case where the color temperature is changed from 6500K to 9300K is described. However, even when the color temperature is converted from another color temperature to another color temperature, the same process is performed. be able to.

  Next, a method for changing the color temperature and the luminance when the liquid crystal display device 10 displays an image or an image will be described with reference to FIG. FIG. 3 is a flowchart showing a process of changing the color temperature and the luminance.

  First, the control unit 13 determines whether a selection signal for changing the color temperature is input from the input unit 12 to the data acquisition unit 16 (S11). Note that the selection to change the color temperature can be performed by a user operation, for example. When it is determined that the selection signal is not input to the data acquisition unit 16 (NO in S11), the control unit 13 determines whether the selection signal is input to the data acquisition unit 16 again. Do. On the other hand, when it is determined that the selection signal is input to the data acquisition unit 16 (YES in S11), the control unit 13 further determines which color temperature has been selected (S12).

  Next, the data acquisition unit 16 obtains color temperature data and luminance data corresponding to the selected color temperature from the LUT (S13). The data acquisition unit 16 outputs the obtained color temperature data to the display control unit 17 and outputs the luminance data to the luminance control unit 18 (S14).

  The display control unit 17 multiplies (weights) the input color temperature data by the currently displayed RGB and converts the RGB data (S15). That is, the currently displayed RGB is input in real time, and this RGB is multiplied by the color temperature data. Then, the display control unit 17 controls the liquid crystal display panel 11 to display a video or an image based on the multiplied RGB data (that is, R′G′B ′) (S16).

  On the other hand, the luminance control unit 18 multiplies (weights) the input luminance data by a value indicating the current luminance, and converts a value indicating the luminance of the light emitted from the backlight 15 (S17). Then, the luminance control unit 18 controls the backlight 15 so as to emit light based on the luminance after multiplication (S18).

  Thereby, the display color on the liquid crystal display panel 11 can be changed to a predetermined color temperature, and the luminance of the light emitted from the backlight 15 can be adjusted so that the luminance corresponds to the color temperature.

  Next, a method for adjusting the brightness of light by controlling the backlight 15 (light control) will be specifically described. Examples of a method for adjusting the luminance of the backlight include a DUTY driving method and a current driving method. In the present invention, any driving method can be adopted.

  The current driving method is a method of adjusting luminance by changing the amount of current flowing through the backlight 15. As the amount of current flowing through the backlight 15 increases, the brightness of light emitted from the backlight 15 increases. Therefore, the luminance can be adjusted by changing the amount of current. In addition, since the brightness | luminance obtained with respect to electric current amount changes with the backlights 15 used, what is necessary is just to set suitably so that it may become the electric current amount according to the backlight 15. Therefore, in the case of the present invention, it is possible to obtain a desired luminance by changing the current flowing through the backlight 15 so that the luminance after the change is obtained.

  On the other hand, the DUTY driving method is a method of adjusting the luminance by changing the ratio of the ON period and the OFF period of the backlight 15 with respect to a certain period. That is, by setting a certain period as one cycle and performing pulse lighting in which the lighting period of the backlight 15 is changed, the luminance can be changed according to the lighting period.

FIG. 4 is a timing chart showing the ON period and OFF period of the backlight 15 when the DUTY driving method is used. As shown in FIG. 4, when the one period and _{t 1, t 1} is adapted from the ON period _{t 2} and the OFF period _{t 3} Prefecture, the backlight 15 by varying the ratio of the _{t 2} and _{t 3} It is possible to change the luminance of the light emitted from.

Thus, the higher the brightness of the light fraction of the ON period t ₂ of the backlight 15 is emitted from the more the backlight 15 increases the more within one period of the cycle t _1. Since the luminance obtained with respect to this ratio varies depending on the backlight 15 to be used, it may be appropriately set so as to be a ratio according to the backlight 15. Therefore, in the case of the present invention, it is possible to obtain a desired luminance by varying the ON period t ₂ of the backlight 15 so that the luminance after the change.

  When the luminance changes according to the characteristics of the backlight 15 to be used, the luminance may be adjusted using a coefficient or a table corresponding to the characteristics of the backlight 15. That is, the luminance data θ is basically calculated from Y / Y ′, but θ can be further corrected according to the characteristics of the backlight 15. In this case, the accuracy of brightness adjustment can be further increased.

  For example, in the DUTY driving method, when the ON period of the backlight 15 is one cycle (when the ON period is 100%), the luminance of light emitted from the backlight 15 is 100%, and the ON period is ON. The relationship between the ON period of the backlight 15 and the output (luminance) from the backlight 15 is 1 as in the case where the luminance of light emitted from the backlight 15 is 50% when the period is 50%. When the ratio is 1, it is not necessary to perform correction according to the characteristics of the backlight 15.

  On the other hand, when the relationship between the ON period of the backlight 15 and the output (luminance) from the backlight 15 is not 1: 1, the accuracy of luminance adjustment is achieved by performing correction according to the characteristics of the backlight 15. Can be increased.

  Examples of the correction in this case include an example in which the value of the luminance data is corrected by calculating a correction coefficient using an equation or a correction table. As a method for calculating the correction coefficient, for example, when the relationship between the ON period of the backlight 15 and the output from the backlight 15 is proportional, the correction coefficient can be calculated using a mathematical formula. On the other hand, when the relationship between the ON period of the backlight 15 and the output from the backlight 15 is not proportional, the correction coefficient may be calculated using the correction table.

  Here, the correction table is a table indicating the characteristics of the backlight 15. FIG. 5 shows a correction table. This correction table shows the relationship between the ON period of the backlight 15 and the luminance (output) from the backlight 15. In FIG. 5, when the ON period of the backlight 15 is 80%, the output from the backlight 15 is 70%, and when the ON period of the backlight 15 is 50%, the backlight The output from 15 is 60%. Therefore, the relationship between the ON period and the output is not a 1: 1 relationship and is not a proportional relationship.

  Therefore, in this case, the correction coefficient is calculated from the correction table when the luminance of the backlight 15 is adjusted. For example, when the luminance changes to 70% due to the change of the color temperature to be displayed, Y / Y ′ = 100/70 = 1.43 is used to adjust the luminance to be constant. However, in order to keep the luminance constant, it is actually necessary to set the ON period to 80%. Therefore, Y / Y ′ is multiplied by (80 ÷ 70 = 1.14), and this value is obtained. Let it be luminance data θ. By multiplying the correction coefficient by Y / Y ′ to obtain the luminance data θ, it is possible to perform more accurate luminance adjustment. This correction coefficient is a coefficient represented by (backlight ON period) / (output from backlight).

  Since the maximum ON period is one period (100%), the ON period does not exceed one period. However, it is preferable to set in advance such that the ON period corresponding to the maximum setting value of Y / Y ′ is one cycle.

  In the present invention, the backlight characteristic is taken into consideration when calculating the luminance data θ as described above, and θ after multiplication by the correction coefficient is stored in the LUT as luminance data. Alternatively, the luminance adjustment may be performed by calculating a correction coefficient and multiplying the luminance data θ and the correction coefficient at the time of luminance adjustment.

  Thereby, when changing the color temperature of the display color, the liquid crystal display device 10 according to the present embodiment can control the backlight 15 so as to emit light having a luminance corresponding to the changed color temperature. As a result, it is possible to improve the decrease in luminance associated with the change in color temperature.

[Embodiment 2]
A second embodiment of the present invention will be described below with reference to FIGS.

  The present embodiment is different from the first embodiment only in the LUT and the control unit, and the other configurations are the same. For this reason, in this embodiment, the LUT and the control unit will be mainly described. Moreover, the same code | symbol is attached | subjected to the member same as Embodiment 1, and the description is abbreviate | omitted.

  In this embodiment mode, a liquid crystal display device will be described as an example. However, the present invention is not limited to this, and a display device capable of performing other color displays such as a CRT or a PDP may be used. This embodiment will also be described using the NTSC system.

  FIG. 6 is a block diagram showing a schematic configuration of a liquid crystal display device (color display device) 20 according to the present embodiment. As shown in FIG. 6, the liquid crystal display device 20 includes a liquid crystal display panel 11, an input unit 12, a control unit (light source control device, light source control means) 23, and a storage unit (storage device) 24.

  The storage unit 24 stores a look-up table (LUT) related to color temperature data associated with various color temperatures. This color temperature data is data relating to RGB necessary for irradiating light of the corresponding color temperature from the liquid crystal display panel, and specifically indicates coefficients for correcting each RGB value as a reference. It is data.

  The control unit 23 controls the entire liquid crystal display device 20. For example, the control unit 23 controls the liquid crystal display panel 11 to display a predetermined video or image at a predetermined color temperature or luminance. is there. The control unit 24 includes a data acquisition unit (acquisition unit) 26, a display control unit (color temperature changing unit) 17, a luminance data generation unit (luminance correction value generation unit) 29, and a luminance control unit (luminance adjustment unit) 28. ing.

  The data acquisition unit 26 acquires color temperature data as necessary. When the data acquisition unit 26 receives the color temperature selection signal from the input unit 12, the data acquisition unit 26 refers to the LUT stored in the storage unit 24 and acquires the changed color temperature data corresponding to the selection signal. The data acquisition unit 26 outputs the acquired color temperature data to the display control unit 17 and the luminance data generation unit 29.

  In the liquid crystal display device 20 of the present invention, the control unit 13 not only outputs the color temperature data to the display control unit 17 and the luminance data generation unit 29, but also displays display data relating to the displayed video and image to the display control unit 17. The structure which outputs may be sufficient, and the means other than the control part 13 may output the display data to the display control part 17.

  The display control unit 17 performs control to change the color temperature displayed on the liquid crystal display panel 11 based on the input color temperature data. As a result, the liquid crystal display panel 11 displays a video or image that has been changed to a predetermined color temperature. The method for changing the color temperature based on the color temperature data can be performed in the same manner as in the first embodiment.

  In addition, the luminance data generation unit 29 generates luminance data for controlling the backlight 15 based on the input color temperature data. The luminance data is data necessary for irradiating light with a corresponding luminance from the backlight 15. Specifically, it is a coefficient for correcting the luminance to correspond to the color temperature to be displayed. This luminance data is generated based on the luminance data at the time of white display and the changed color temperature data. The luminance data generation unit 29 outputs the generated luminance data to the luminance control unit 28. Note that a method by which the luminance data generation unit 29 generates luminance data will be described later.

  The luminance control unit 28 controls the backlight 15 based on the luminance data input from the luminance data generation unit 29. The luminance control unit 28 controls the backlight 14 to adjust the luminance of light emitted from the backlight 15, and light having a predetermined luminance is emitted from the backlight 15. The method for controlling the backlight 15 based on the luminance data can be performed in the same manner as in the first embodiment.

  Next, the LUT will be specifically described with reference to FIG. FIG. 7 is a diagram showing the LUT according to the present embodiment. The LUT is a table storing settings for identifying each color temperature and color temperature data associated with each color temperature. Thus, luminance data is not stored in the LUT according to the present embodiment. In other words, the present embodiment is not configured to calculate the luminance data in advance, but is configured to calculate the corresponding luminance data when the color temperature is set and to control the backlight 15 based on the luminance data. In FIG. 7, for convenience of explanation, only data relating to three types of color temperatures is shown, but the number thereof may be set as appropriate and is not limited to this LUT.

  As shown in FIG. 7, data (αa, βa, γa), (αb, βb, γb), (αc, βc, γc),... Are associated with setting A, setting B, setting C. ing. Setting A, setting B, setting C,... Are identification data for identifying the color temperature.

  That is, in the LUT, each setting is associated with each color temperature data. For example, (αa, βa, γa) will be described as an example. Αa, βa, and γa are color temperature data corresponding to the setting A, and are used to correct the displayed color temperature (R, G, B). Is the coefficient.

  When changing the color temperature, if the color temperature at the time of white display at 6500 K is (R, G, B), the color temperature (R ′, G ′, B ′) after the change (a color display) is (ΑaR, βaG, γaB). That is, R ′ = αaR, G ′ = βaG, B ′ = γaB, and by using the color temperature at the time of white display of 6500K and the coefficient corresponding to the changed color temperature, the changed color temperature (R ', G', B ') can be calculated. Note that R: G: B = 1: 1: 1.

  Next, a method in which the luminance data generation unit 29 generates the luminance data θ based on the color temperature data will be described.

  First, as in the first embodiment, for example, the relationship between RGB and luminance Y when displaying white at 6500 K can be obtained by the above equation (3). That is, the luminance Y corresponding to RGB used in 6500K white display (R: G: B = 1: 1: 1) can be obtained from the above equation (3).

  On the other hand, the preferable luminance Y ′ of the light emitted from the backlight 15 corresponding to the changed color temperature (color temperature corresponding to the selected setting) can be obtained by the above equation (4). That is, the luminance data generation unit 29 obtains a preferable luminance Y ′ of the backlight 15 corresponding to the changed color temperature using the changed value of R′G′B ′.

  Furthermore, since θ = Y / Y ′, the luminance data generation unit 29 can calculate the luminance data θ based on the Y and Y ′. Then, the luminance data generation unit 29 outputs the calculated luminance data θ to the luminance control unit 28, and the luminance control unit 28 controls the backlight 15 based on the luminance data θ. Thereby, the brightness emitted from the backlight 15 can be adjusted.

  As in the first embodiment, the color temperature from 6500K (R = 100, G = 100, B = 100) to 9300K (R = 72.9, G = 84.5, B = 100). In the case of changing to, the luminance data θ is 100 ÷ 82.8 = 1.2.

  Accordingly, the luminance data generation unit 29 calculates the luminance data θ = 1.2, and the luminance control unit 28 controls the backlight 15 to increase the luminance by 1.2 (the luminance corresponding to the changed color temperature). By multiplying the brightness data θ = 1.2 by the value indicating the brightness of the light source, it is possible to control the backlight 15 to adjust the brightness of the light emitted from the backlight 15 and to improve the brightness reduction. it can.

  Also in the present embodiment, as in the first embodiment, when the luminance changes according to the characteristics of the backlight 15, the luminance is calculated using a coefficient or a table corresponding to the characteristics of the backlight 15. You may adjust. This brightness adjustment method can be performed in the same manner as in the first embodiment.

  Here, the calculation method of the luminance data θ will be specifically described. There are three types of color temperatures that can be set (setting A, setting B, setting C), (αa, βa, γa) of setting A is (1, 1, 1), and (αb, βb, γb) of setting B is A case where (1, 0.9, 0.8) and (αc, βc, γc) of setting C is (1, 0.8, 0.7) will be described.

  First, the luminance of light emitted from the backlight 15 when the liquid crystal display device 20 displays white at a color temperature of 6500K is set to Y = 1. Here, assuming that the brightness data when the color temperature is changed from the setting A to the setting B is θb, Y ′ = 1.09 from the above equation (4), so θb = Y / Y ′ = 0.919. Become. If the luminance data when changing the color temperature from setting A to setting C is θc, Y ′ = 1.18 from the above equation (4), and θc = Y / Y ′ = 0.847. . In this way, the luminance data θ can be calculated.

  Next, a method for changing the color temperature and the luminance when the liquid crystal display device 20 displays an image or an image will be described with reference to FIG. FIG. 8 is a flowchart showing a process of changing the color temperature and the luminance.

  First, the control unit 23 determines whether a selection signal for changing the color temperature is input from the input unit 12 to the data acquisition unit 26 (S21). Note that the selection to change the color temperature can be performed by a user operation, for example. When it is determined that the selection signal is not input to the data acquisition unit 26 (NO in S21), the control unit 23 determines whether the selection signal is input to the data acquisition unit 26 again. Do. On the other hand, when it is determined that the selection signal has been input to the data acquisition unit 26 (YES in S21), the control unit 23 further determines which color temperature has been selected (S22).

  Next, the data acquisition unit 26 acquires color temperature data corresponding to the selected color temperature from the LUT (S23). The data acquisition unit 26 outputs the obtained color temperature data to the display control unit 17 and the luminance data generation unit 29 (S24).

  The display control unit 17 multiplies (weights) the input color temperature data by the currently displayed RGB and converts the RGB data (S25). That is, the currently displayed RGB is input in real time, and this RGB is multiplied by the color temperature data. Then, the display control unit 17 controls the liquid crystal display panel 11 to display a video or an image based on the multiplied RGB data (that is, R′G′B ′) (S26).

  On the other hand, the luminance data generation unit 29 generates luminance data based on the input color temperature data and outputs the luminance data to the luminance control unit 28 (S27). Then, the luminance control unit 28 multiplies (weights) the input luminance data by a value indicating the current luminance, and converts a value indicating the luminance of the light emitted from the backlight 15 (S28). Next, the luminance control unit 28 controls the backlight 15 to emit light based on the luminance after multiplication (S29).

  Thereby, the display color on the liquid crystal display panel 11 can be changed to a predetermined color temperature, and the luminance of the light emitted from the backlight 15 can be adjusted so that the luminance corresponds to the color temperature.

  In addition, the method of adjusting the luminance of light by controlling the backlight 15 (dimming) can be performed using, for example, a DUTY driving method or a current driving method, as in the first embodiment.

  Thereby, when changing the color temperature of the display color, the liquid crystal display device 20 according to the present embodiment can control the backlight 15 so as to emit light having a luminance corresponding to the changed color temperature. As a result, it is possible to improve the decrease in luminance associated with the change in color temperature.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention.

  Finally, each block of the control units 13 and 23, in particular, the display control unit 17, the luminance control unit 18, and the luminance data generation unit 29 may be configured by hardware logic, or software using a CPU as follows. It may be realized by.

  That is, the control units 13 and 23 are a CPU (central processing unit) that executes instructions of a control program for realizing each function, a ROM (read only memory) that stores the program, and a RAM (random access memory) that expands the program. ), A storage device (recording medium) such as a memory for storing the program and various data. An object of the present invention is a recording medium in which the program code (execution format program, intermediate code program, source program) of the control program of the control units 13 and 23, which is software that realizes the functions described above, is recorded in a computer-readable manner. Can also be achieved by reading the program code recorded on the recording medium and executing it by the computer (or CPU or MPU).

  Examples of the recording medium include a tape system such as a magnetic tape and a cassette tape, a magnetic disk such as a floppy (registered trademark) disk / hard disk, and an optical disk such as a CD-ROM / MO / MD / DVD / CD-R. Card system such as IC card, IC card (including memory card) / optical card, or semiconductor memory system such as mask ROM / EPROM / EEPROM / flash ROM.

  The control units 13 and 23 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Also, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

  As described above, the light source control device and the color display device of the present invention can keep the luminance of the light emitted from the light source constant when the color temperature is converted. The present invention can be widely applied to an image display device provided in a device, a car navigation system, or the like. Therefore, the present invention can be suitably used not only in the industrial field for manufacturing display devices, but also in the industrial field for manufacturing various electronic / electrical devices and parts thereof.

1 is a block diagram illustrating a schematic configuration of a liquid crystal display device according to an embodiment of the present invention. 1 is a diagram illustrating an LUT according to an embodiment of the present invention. 4 is a flowchart illustrating a process of changing a color temperature and luminance according to an embodiment of the present invention. FIG. 2 is a timing chart illustrating an embodiment of the present invention and illustrating an ON period and an OFF period of a backlight. FIG. 3 is a diagram illustrating a correction table according to an embodiment of the present invention. FIG. 24, showing another embodiment of the present invention, is a block diagram illustrating a schematic configuration of a liquid crystal display device. FIG. 10 is a diagram showing an LUT according to another embodiment of the present invention. FIG. 10 is a flowchart illustrating another embodiment of the present invention and a process of changing color temperature and luminance.

Explanation of symbols

10.20 Liquid crystal display device (color display device)
DESCRIPTION OF SYMBOLS 11 Liquid crystal display panel 12 Input part 13.23 Control part (light source control apparatus, light source control means)
14.24 Storage unit (storage device)
15 Backlight (light source)
16.26 Data acquisition unit (acquisition means)
17 Display controller (color temperature changing means)
18.28 Luminance control unit (luminance adjustment means)
29 Luminance data generation unit (luminance correction value generation means)

Claims (12)

A light source control device that includes a light source and is used in a color display device that changes a color temperature based on color temperature information and controls the light source,
Acquisition means for acquiring the color temperature information and a luminance correction value associated with the color temperature information and correcting the luminance of light emitted from the light source;
A light source control apparatus comprising: a brightness adjusting unit that adjusts the brightness of light emitted from the light source based on the brightness correction value. A light source control device that includes a light source and is used in a color display device that changes a color temperature based on color temperature information and controls the light source,
Obtaining means for obtaining the color temperature information;
A luminance correction value generating means for generating a luminance correction value for correcting the luminance of the light emitted from the light source based on the color temperature information;
A light source control apparatus comprising: a brightness adjusting unit that adjusts the brightness of light emitted from the light source based on the brightness correction value.   The brightness adjustment means weights a brightness correction value associated with the color temperature after the change to a value indicating the brightness associated with the color temperature after the change. The light source control device according to 2.   4. The luminance correction value is a coefficient calculated based on a luminance associated with a reference color temperature and a luminance associated with a changed color temperature. The light source control device according to any one of the above. A color display device that changes color temperature based on color temperature information,
A light source;
Light source control means for controlling the light source;
A storage device that stores the color temperature information and a brightness correction value that is associated with the color temperature information and corrects the brightness of the light emitted from the light source;
The light source control means obtains a brightness correction value associated with the changed color temperature from the storage device;
A color display device comprising: a luminance adjusting unit that adjusts the luminance of the light emitted from the light source based on the luminance correction value acquired by the acquiring unit. A color display device that changes color temperature based on color temperature information,
A light source;
Light source control means for controlling the light source;
A storage device storing the color temperature information,
The light source control means obtains color temperature information associated with the changed color temperature from the storage device;
A luminance correction value generating means for generating a luminance correction value for correcting the luminance of the light emitted from the light source based on the color temperature information acquired by the acquisition means;
A color display device comprising: luminance adjusting means for adjusting the luminance of light emitted from the light source based on the luminance correction value.   The color temperature changing means for changing the color temperature to be displayed based on the color temperature information associated with the color temperature after the change obtained by the obtaining means is further provided. The color display device described in 1.   6. The brightness adjustment unit weights a brightness correction value associated with the color temperature after the change to a value indicating the brightness associated with the color temperature after the change. 8. The color display device according to any one of items 7.   9. The luminance correction value is a coefficient calculated based on a luminance associated with a reference color temperature and a luminance associated with a converted color temperature. The color display device according to any one of the above. A color display method for emitting light from a light source and changing the color temperature based on the color temperature information,
Obtaining color temperature information associated with the color temperature after the change, and a luminance correction value for correcting the luminance of the light emitted from the light source associated with the color temperature information;
A color display method comprising adjusting the luminance of light emitted from a light source based on the luminance correction value. A color display method for emitting light from a light source and changing the color temperature based on the color temperature information,
Obtain color temperature information associated with the changed color temperature,
Based on the acquired color temperature information, generate a luminance correction value for correcting the luminance of the light emitted from the light source,
A color display method comprising adjusting the luminance of light emitted from a light source based on the luminance correction value.   The color according to claim 10 or 11, wherein a luminance correction value associated with the color temperature after the change is weighted with respect to a value indicating the luminance associated with the color temperature after the change. Display method.

Images