KR101423112B1 - Light generating device, display device having the same, and driving method thereof - Google Patents

Abstract

A light generating device for compensating for white light uniformity and a display device employing the same. This light generating device includes a luminance detecting portion. The luminance detector extracts luminance data from input image data. The light generating device performs a correction operation to compensate for the uniformity of white light whenever image data of a reference gradation or higher is input through the luminance detector. Therefore, the light generating device can achieve white light uniformity in real time. Further, the display device employing this light generating device provides a further improved display quality.

Description

TECHNICAL FIELD [0001] The present invention relates to a light generating device, a display device having the light generating device,

BRIEF DESCRIPTION OF THE DRAWINGS For a more complete understanding of the drawings used in the detailed description of the invention, a brief description of each drawing is provided.

1 is a block diagram showing a configuration of a light generating device according to the present invention.

2 is a diagram showing the configuration of the luminance detector shown in FIG.

Fig. 3 is a diagram showing a configuration of the light source correcting unit shown in Fig. 1. Fig.

4 is a diagram showing a configuration of the color temperature correction unit shown in FIG.

5 is a block diagram of a display device employing the light generating device shown in Fig.

6 is a flowchart showing the driving method of the light generating device shown in Figs. 1 and 5. Fig.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light generating device, a display device having the same, and a driving method thereof, and more particularly, to a light generating device for uniformly controlling light uniformity, a display device having the same and a driving method thereof.

2. Description of the Related Art Generally, a backlight unit for providing light to a display panel is widely used as a cold cathode fluorescent lamp (CCFL) and a light emitting diode (LED) .

LEDs have many advantages over CCFLs. For example, in constructing a backlight unit, LEDs are less restricted in size than CCFLs. In addition, the LEDs are individually adjustable in brightness. In addition, the CCFL has a dimming range of 25% to 100%, while the LED has a brightness control range of 0% to 100% in theory. Because of these many advantages, the use of LEDs as a backlight unit is increasing.

On the other hand, in order to provide a more improved display quality, a display device equipped with an LED uses various types of LED driving methods. Currently, LED driving methods that are mainly used are scanning-impulsive, sequential scanning, and localized dimming. Particularly, the local dimming method can overcome the limitation of the contrast ratio (CR) generated by using a backlight unit that emits light of a constant brightness.

However, the LED has an optical characteristic such as a color coordinate (or a color temperature) and a device characteristic that the luminance changes as time and temperature change. Such device characteristics degrade the white light uniformity (also referred to as "white color balancing") emitted from the LED. Therefore, the backlight unit employing LEDs must appropriately compensate for the uniformity of white light. Here, the term "uniformity of white light" refers to a degree of how white is uniformly displayed when a full white pattern is displayed on the entire display screen.

Recently, a color feedback system (hereinafter referred to as 'CFS') using an optical sensor has been developed to compensate for the uniformity of white light.

Briefly explaining this CFS, the CFS detects the amount of light emitted from the entire LED through an optical sensor mounted inside the backlight unit, and converts the detected amount of light into a voltage signal. The CFS compares the converted voltage signal and the reference signal, and outputs a control signal based on the comparison result. The LED driving circuit adjusts a driving current supplied to the LED in response to the control signal. The LED emits the target light in response to the regulated drive current.

However, it is very difficult to apply this CFS in an LED backlight driven by a split driving method. This is because a local dimming type LED backlight unit that individually adjusts the luminance of the divided areas needs to have a sensor for each divided area. Therefore, a large cost is required. Further, the LED driving unit of the divided driving type should block the light interference from the adjacent area of the area to be sensed by the sensor. Therefore, there is a technical difficulty in applying the CFS to the backlight unit of the divided driving type.

Accordingly, an object of the present invention is to provide a light generating device capable of real-time compensation of light uniformity.

Another object of the present invention is to provide a display device including the light generating device.

It is still another object of the present invention to provide a method of driving the light generating device.

According to an aspect of the present invention, there is provided a light generator including a luminance detector, a dimming signal controller, a light source driver, a light source, and a light source corrector.

Wherein the luminance detector receives a plurality of image data from the outside, detects and outputs a plurality of luminance data corresponding to the plurality of image data, compares a plurality of gradations corresponding to the plurality of image data with a reference gradation, And outputs an enable signal based on the comparison result.

The dimming signal controller receives the correction signal and the brightness data, and outputs a first dimming signal corresponding to the brightness data and a second dimming signal corrected based on the correction signal.

The light source driving unit outputs a driving signal in response to any one of the first and second dimming signals from the dimming signal control unit.

The light source unit includes a plurality of light source units for generating white light in response to the driving signal.

The light source correction unit starts driving in response to the enable signal, receives the white light emitted from the light source unit, and outputs the correction signal to correct the optical characteristics of the white light.

 According to another aspect of the present invention, there is provided a display device including a display unit and a light generator. The display unit displays an image corresponding to image data provided from the outside using white light.

The light generating device is formed below the display unit to generate the white light. The light generating device provided in the display device of the present invention has the same components and functions as the above-described light generating device. Therefore, a detailed description thereof will be omitted.

According to another aspect of the present invention, there is provided a method of driving a light emitting device, the method including receiving a plurality of image data from the outside. Extracts luminance data from the image data, and compares the gradation of the image data with a preset gradation. And outputs a dimming signal of a first dimming signal corresponding to the brightness data and a second dimming signal corrected for the first dimming signal based on the comparison result. Generates a driving signal corresponding to one of the output dimming signals, and emits a white light corresponding to the driving signal.

According to the light generating device, the display device having the same, and the driving method thereof, a correction operation for compensating for the uniformity of white light is performed every time image data of a predetermined reference gradation or higher is input.

Thus, the light generating device of the present invention compensates for the uniformity of white light in real time, thereby providing more improved white light uniformity. Furthermore, the display device of the present invention employing the above light generating device provides improved display quality.

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

In understanding each of the figures, it should be noted that like parts are denoted by the same reference numerals whenever possible. In addition, many specific details, such as the specific process flow in the following description, are set forth to provide a more thorough understanding of the present invention. And detailed descriptions of known functions and configurations that may unnecessarily obscure the gist of the present invention are omitted.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings.

1 is a block diagram showing a configuration of a light generating device 100 according to the present invention.

1, a light generating apparatus 100 according to the present invention includes a luminance detector 110 for detecting luminance data LS from image data DS, a luminance detector 110 for outputting a dimming signal corresponding to the luminance data LS, A light source driving unit 130 for outputting a driving signal corresponding to the dimming signal, a light source unit 140 for emitting white light in response to the driving signal, and a light source unit 140 for correcting the optical characteristics of the emitted white light And a light source correcting unit 150. In addition, the light-generating device 100 according to the present invention further includes a frame memory 105. The frame memory 105 stores input image data DS on a frame-by-frame basis. The stored image data DS is output to the luminance detector 110.

2 is a diagram showing a configuration of the luminance detector 110 shown in FIG.

Referring to FIG. 2, the luminance detector 110 includes a luminance data extractor 112 and an image analyzer 114.

The luminance data extracting unit 112 receives a plurality of image data DS corresponding to one frame through the frame memory 105 and receives a plurality of luminance data LS from each of the plurality of image data DS, And outputs it.

Each image data DS is digital data including image information, and includes red (R) data, green (G) data, and blue (B) data. Therefore, the luminance data LS detected from each image data DS includes red luminance data rLS, green luminance data gLS, and blue luminance data bLS.

In this embodiment, a light source made up of LED light emitting diodes of three colors (e.g., red, green, and blue) is used. Therefore, the red luminance data rLS is used to adjust the light amount of the red light emitting diode, and the green luminance data gLS is used to adjust the light amount of the green light emitting diode. The blue luminance data (bLS) is used to adjust the amount of light of the blue light emitting diode. Each light quantity of the red, green and blue light emitting diodes is mixed to form white light. Of course, a light source composed of a single-color (white) LED light-emitting diode may also be used.

On the other hand, the image data DS does not include luminance data. Accordingly, the brightness data extracting unit 112 converts the image data DS into color space data through a well-known color space conversion algorithm, and extracts the image data DS from the color space data (LS) corresponding to the luminance data DS.

The image analyzer 114 extracts a plurality of gradations from each image data DS, and compares the extracted plurality of gradations with predetermined reference gradations. The image analyzing unit 114 outputs an enable signal EN when all of the plurality of gradations are equal to or greater than the preset reference gradation. The predetermined reference gradation can be set variously by the system designer, and is preferably set to 1/2 of the entire gradation section. For example, when the total gradation is 256 gradations, the reference gradation is set to 127 gradations.

1, the dimming signal controller 120 receives luminance data LS from the luminance detector 110 and a correction signal CS from the light source corrector 150. The dimming signal controller 120 outputs a dimming signal of either the first dimming signal DIM1 corresponding to the brightness data LS or the second dimming signal DIM2 corrected for the first dimming signal.

The first dimming signal DIM1 corresponds to the first red dimming signal corresponding to the red luminance data rLS, the first blue dimming signal corresponding to the blue luminance data bLS, and the green luminance data gLS And a second green dimming signal. The second dimming signal may include a second red dimming signal corrected for the first red dimming signal, a second green dimming signal corrected for the first green dimming signal, and a second blue dimming signal corrected for the first blue dimming signal. And a dimming signal.

For reference, the dimming signal is a pulse-shaped signal generated to adjust the luminance of the white light emitted from the light source when the power saving mode or the contrast ratio (C / R) of the display screen is to be increased.

The dimming signal controller 120 adjusts the duty ratio of the dimming signals DIM1 and DIM2 to adjust the brightness of the white light of the light source. Here, duty ratio refers to the ratio of the high section to one pulse period. This method is called Pulse Width Modulation (PWM). The luminance of the white light increases as the ratio of the high section increases.

The duty ratio is set in advance according to the gradation of input image data. For example, if the total gradation is 256 gradations, a duty ratio is set for each gradation unit. Accordingly, when the luminance data corresponding to the 0th gradation is input, the dimming signal controller 120 outputs the dimming signal having the minimum duty ratio. When the luminance data corresponding to the 256th gradation is input, the dimming signal controller 120 outputs the dimming signal having the maximum duty ratio Output.

In the embodiment of the present invention, the duty ratio is not set for each of all the gradations. That is, the duty ratio is set only for the previous gradation period of the predetermined reference gradation in the entire gradation period, and is set to have the maximum duty ratio in all the remaining gradation periods. Therefore, the white light emitted from the light source unit 140 is maintained only at the maximum luminance without the brightness control at the predetermined reference gradation or higher in the entire gradation period.

The light source driving unit 130 generates a driving voltage Vd corresponding to one of the first and second dimming signals DIM1 and DIM2 provided from the dimming signal controller 120, do. The driving voltage Vd includes a red driving voltage, a green driving voltage, and a blue driving voltage.

The light source unit 140 includes the plurality of light sources that generate white light in response to the driving voltage Vd. Each of the plurality of light sources includes red, blue and green light emitting diodes (LEDs). The red, green, and blue light emitting diodes receive the red driving voltage, the green driving voltage, and the blue driving voltage, respectively, and emit the respective color lights (red light, green light, and blue light). The emitted color light is mixed according to the light amount of each of them and emits white light. Here, the plurality of light sources are divided into a plurality of groups, and the light sources provided in each of the blocks independently operate with the light sources provided in adjacent blocks.

The light source correcting unit 150 starts driving in response to the enable signal EN from the image analyzing unit 110. The light source correction unit 150 receives the white light emitted to the light source unit 140 and outputs the correction signal CS to correct the optical characteristics of the white light.

FIG. 3 is a block diagram showing a configuration of the light source correcting unit 150 shown in FIG.

Referring to FIG. 3, the light source correction unit 150 includes a light sensing unit 152, a light detection unit 154, a first correction unit 156, and a second correction unit 158. The light sensing unit 152 includes at least one light sensor for sensing the amount of white light output from a plurality of light sources.

The light sensing unit 152 converts red light, green light, and blue light constituting the sensed white light into current values Ri, Gi, and Bi, respectively, and outputs the current values.

The photodetector 154 converts the current values Ri, Gi, and Bi into voltage values Rv, Gv, and Bv, respectively, and outputs the voltage values. This is because the adjustment of the voltage values Rv, Gv, Bv is easier than the current values Ri, Gi, Bi. Hereinafter, the voltage values Rv, Gv, and Bv are referred to as photodetection signals.

The first correction unit 156 receives the light detection signals Rv, Gv, and Bv and compares the luminance values corresponding to the light detection signals Rv, Gv, and Bv with the previously stored target luminance values , And outputs the first correction data Rv1, Gv1, and Bv1 based on the comparison result.

The first correction unit 156 includes a first memory unit 156a and a brightness correction unit 156b. The first memory unit 156a stores the target luminance value in the form of a look-up table. The luminance correction unit 156b compares the difference between the stored target luminance value and the luminance value corresponding to the light detection signals Rv, Gv, and Bv, and based on the comparison value, And outputs data CS1 (Rv2, Gv2, Bv2). The output first correction data CS1 is applied to the dimming signal controller 120.

The second correction unit 158 receives the light detection signals Rv, Gv, and Bv and compares the color temperature values corresponding to the light detection signals Rv, Gv, and Bv with pre-stored target color temperature values , And outputs the second correction data (CS2: Rv2, Gv2, Bv2) based on the result of this comparison operation.

Specifically, the second correction unit 158 includes a second memory unit 158a and a color temperature correction unit 158b. The second memory unit 158a stores the target color temperature value in the form of a look-up table. In addition, the second memory unit 158a may store the target color temperature value in the form of a look-up table corresponding to the target X coordinate value and the target Y coordinate value corresponding to the CIE coordinate system.

The color temperature correction unit 158b reads the stored target color temperature value and compares the difference between the read target color temperature value and the color temperature value corresponding to the light detection signals Rv, Gv, Bv, And outputs the second correction data CS2 (Rv2, Gv2, Bv2) based on the difference value.

4 is a block diagram showing a configuration of the color temperature correction section 158b shown in FIG.

Referring to FIG. 4, the color temperature correction unit 158b includes an XYZ conversion unit 158b1, a chromaticity calculation unit 158b2, a coordinate correction unit 158b3, and a color temperature conversion unit 158b4.

The XYZ conversion unit 158b1 receives the photodetection signals Rv, Gv, and Bv and converts the photodetection signals Rv, Gv, and Bv into XYZ values of the CIE coordinate system.

The chromaticity calculation unit 158b2 calculates the raw X coordinate (X) in accordance with the distribution of the converted XYZ value to the color temperature value corresponding to the white area of the CIE coordinate system, and based on the calculated raw X coordinate (X) Thereby calculating a raw Y-coordinate (Y).

The coordinate correcting unit 158b3 reads the target X coordinate X 'and the target Y coordinate Y' of the CIE coordinate system corresponding to the target color temperature value stored in the second memory unit 158a, X ') and the target Y coordinate (Y') and the raw X coordinate (X) and the raw Y coordinate (Y) input from the chromaticity calculator 158a-2. The coordinate correcting unit 158a-3 outputs the corrected X coordinate (X ") and the corrected Y coordinate (Y") according to the comparison result.

Specifically, the coordinate correcting unit 158b3 calculates the X coordinate difference value between the raw X coordinate X and the target X coordinate X 'and the Y coordinate difference between the raw Y coordinate Y and the target Y coordinate Y' And outputs the corrected X coordinate (X ") and the corrected Y coordinate (Y") based on the X coordinate difference value and the Y coordinate difference value, respectively.

The color temperature converting unit 158b4 calculates the corrected color temperature value corresponding to the light detection signals Rv, Gv, and Bv based on the corrected X coordinate X "and the corrected Y coordinate Y" And outputs second correction data CS2 (Rv2, Gv2, Bv2) corresponding to the calculated corrected color temperature value. The output second correction data CS2 is applied to the dimming signal controller 120. [

The dimming signal controller 120 receives the luminance data LS from the luminance detector 110 and generates the first dimming signal DIM1 and the second dimming signal DIM2 based on the correction signal CS from the light source corrector 150. [ And generates and outputs a second dimming signal DIM2 corrected for the first dimming signal DIM1. The dimming signal controller 120 may further include a memory capable of storing the first and second correction data CS1 and CS2 and may control the first and second correction data CS1 and CS2 to control the dimming signal And stored in the memory as necessary reference data.

5 is a block diagram of a display device employing the light generating device 100 shown in Fig. Here, among the components shown in FIG. 5, the components shown in FIG. 1 are denoted by the same reference numerals, and a detailed description thereof will be briefly described.

5, the display device 1000 includes a display unit 200 and a light generating device 100. [

The display unit 200 includes a liquid crystal display panel 210, a gradation voltage generator 220, a data driver 230, a gate driver 240, and a signal controller 250.

The liquid crystal display panel 210 displays an image in response to second data signals D1 to Dm corresponding to the first data signals R, G and B provided from the signal controller 250.

The liquid crystal display panel 210 includes first to nth gate lines GL1 to GLn and first to mth gate lines GL1 to GLn, And data lines DL1, ..., DLm. On the liquid crystal display panel, two adjacent gate lines among the first to nth gate lines GL1 to GLn and first to mth data lines DL1 to DLm, The pixel region PA is defined by the data lines.

A thin film transistor 216 connected to first to nth gate lines GL1 to GLn and first to mth data lines DL1 to DLm is connected to the pixel region PA, (218).

The gradation voltage generator 220 generates a plurality of gradation voltages corresponding to an image signal input from the outside and provides the gradation voltages to the data driver 230.

The data driver 230 receives a gray scale voltage corresponding to the stored first data signals R, G, and B among a plurality of gray scale voltages input from the gray scale voltage generating unit 220, (D1, ..., Dm). The data driver 230 sequentially supplies the second data signals D1 to Dm to the first to mth data lines DL1 to DLm in response to a first timing signal T1. .

The gate driver 240 sequentially applies the gate driving signals G1 to Gn to the first to nth gate lines GL1 to GLn in response to the second timing signal T2. Output. Each pixel region PA of the liquid crystal display panel 210 is provided with a thin film transistor 216 which serves as a switching transistor. The thin film transistor 216 is turned on or off by the gate driving signals G1, ..., Gn. The second data signals D1, ..., Dm are transferred to the corresponding liquid crystal capacitors 218 by the switching operation of the thin film transistor 216. [

The signal controller 250 generates the first data signals R, G and B, the first timing signal T1 and the second timing signal T2 (T2) in response to the video signal DS in the form of a digital signal provided from the outside, ). The first data signals R, G, and B are R, G, and B signals in the form of digital signals. Also, the signal controller 250 includes a frame memory, and the generated first data signals R, G, and B are stored in the frame memory on a frame-by-frame basis. The stored first data signals R, G, and B are input to the luminance detector 110. [

The first timing signal T1 includes an output instruction signal TP and a second data signal D1, ..., Dm for instructing the liquid crystal display panel 210 to apply the second data signals D1, ..., Dm. (RVS) for inverting the polarity of the data voltage corresponding to the data voltage (Vcc, ..., Dm), and the like.

The second timing signal T2 includes a gate clock signal Gate for setting the period of the gate driving signals G1, ..., Gn applied to the first to nth gate lines GL1, ..., a vertical synchronization start signal STV for commanding the start of the gate driving signals G1 to Gn and an output enable signal OE for enabling the output of the gate driving unit 240. [ Out Enable).

5, the brightness detector 110 directly receives the image data DS through the frame memory 105. However, the image data DS may be received through the signal controller 250 have. In this case, the frame memory 105 shown in FIG. 5 may be replaced with a frame memory provided in the signal controller 250 itself.

In this embodiment, the brightness detector 110 is designed to be separated from the signal controller 250. However, the brightness controller 110 may be designed to be provided in the signal controller 250.

6 is a flowchart showing the driving method of the light generating device 100 shown in Figs. 1 and 5. Fig.

Referring to FIG. 6, a plurality of image data is received from the outside (S610).

A plurality of luminance data is extracted from the received plurality of image data, and a plurality of gradations corresponding to the plurality of image data are extracted in order to analyze the image pattern of the received plurality of image data (S620).

Thereafter, the image patterns of the plurality of image data are analyzed by comparing the extracted plurality of gradations with predetermined reference gradations. Specifically, if the extracted plurality of gradations is larger than the reference gradation, the image pattern is determined as a full white pattern (S630). On the other hand, if at least one of the extracted plurality of gradations is smaller than the reference gradation, the received image pattern is not a full white pattern.

 If the received image pattern is not a full white pattern, the first dimming signal DIM1 corresponding to the extracted luminance data is output (S640). If the received image pattern is a full white pattern, The first dimming signal corresponding to the extracted brightness data is corrected and output as the second dimming signal DIM2 (S650).

A driving voltage corresponding to one of the first and second dimming signals is generated (S660). White light corresponding to the generated driving voltage is generated (S670).

As described above, according to the light generating device, the display device having the same, and the control method thereof, the light generating device compensates for the uniformity of the white light every time the image data of the reference gradation or higher is input through the brightness detecting portion And performs a correction operation.

As described above, the light generating device according to the present invention compensates for the uniformity of white light in real time to provide improved white light uniformity.

Further, the display device of the present invention employing the above light generating device provides an improved display quality.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. Accordingly, the true scope of protection of the present invention should be determined by the technical idea of the appended claims.

Claims (19)

A plurality of luminance data corresponding to the plurality of image data is detected and output, a plurality of gradations corresponding to the plurality of image data are compared with a reference gradation, A luminance detector for outputting an enable signal based on the enable signal; A dimming signal controller for receiving a correction signal and the plurality of luminance data and outputting a first dimming signal corresponding to the luminance data and a second dimming signal corrected for the first dimming signal based on the correction signal; A light source driver for outputting a driving signal in response to any one of the first and second dimming signals from the dimming signal controller; A light source unit including a plurality of light sources for generating white light in response to the driving signal; And And a light source correction unit for starting driving in response to the enable signal and receiving the white light emitted from the light source and outputting the correction signal to correct the optical characteristics of the white light. The method according to claim 1, Further comprising a frame memory for storing image data corresponding to at least one frame and providing the stored image data to the luminance detector. The method according to claim 1, And the optical characteristic of the white light is a luminance value. The method according to claim 1, Wherein the optical characteristic of the white light is any one of a color coordinate and a color temperature. The method according to claim 1, Wherein the reference gradation is a gradation corresponding to 1/2 of the entire gradation section. 6. The method of claim 5, Wherein the dimming signal controller outputs a dimming signal having a predetermined duty ratio if all of the plurality of image data are equal to or greater than the reference gray-scale level. The method according to claim 1, Wherein the luminance detector comprises: An image analyzer receiving the plurality of image data and generating and outputting the enable signal when a plurality of gradations corresponding to the plurality of image data are all higher than a reference gradation; And And a brightness data extracting unit that extracts a plurality of brightness data from each of the plurality of video data. The light generating device of claim 1, wherein each of the plurality of light sources includes red, green, and blue light emitting diodes. 2. The method of claim 1, wherein the correction signal comprises first and second correction data, Wherein the light source correcting unit comprises: A light sensing unit for sensing a light amount of the white light; A photodetector for outputting a photodetection signal corresponding to the sensed amount of light; A first correction unit that receives the light detection signal, compares a luminance value of the light detection signal with a previously stored target luminance value, and outputs the first correction data based on the comparison result; And And a second correction unit that receives the light detection signal and compares the color temperature value of the light detection signal with a predetermined target color temperature value and outputs the second correction signal based on the comparison result . 10. The method of claim 9, Wherein the first correction unit comprises: A first memory unit storing the target luminance value; And And a control unit configured to read the stored target luminance value, calculate a difference value between the read target luminance value and the luminance value of the optical detection signal, and correct the luminance value of the optical detection signal based on the difference value, And a luminance correction unit for outputting data, Wherein the second correction unit comprises: A second memory unit storing the target color coordinate value; And And a second color coordinate value calculating unit for calculating a difference value between the read target color coordinate value and a color coordinate value corresponding to the light detection signal by reading the stored target color coordinate value and correcting the color temperature value of the light detection signal based on the difference value, And a color temperature correction section for outputting the correction data. The color temperature correction apparatus according to claim 10, An XYZ transformer receiving the light detection signal and converting the input light detection signal into an XYZ value of a CIE coordinate system; A chromaticity calculation unit for calculating a raw X coordinate of the photodetection signal based on the distribution of color temperature values of the CIE coordinate system and calculating a raw Y coordinate based on the calculated raw X coordinate; A target color temperature value stored in the second memory unit is read out to calculate a target X coordinate and a target Y coordinate corresponding to the read target color temperature value and an X coordinate difference value between the target X coordinate and the raw X coordinate, A difference between a Y coordinate difference between the Y coordinate and the original Y coordinate is calculated and a corrected X coordinate and a corrected Y coordinate obtained by correcting the raw X coordinate and the raw Y coordinate respectively based on the X coordinate difference value and the Y coordinate difference value, A coordinate correcting unit for outputting the coordinate; And And a color temperature converting unit for correcting the color temperature value of the light detection signal based on the corrected X coordinate and the corrected Y coordinate and outputting the second correction data corresponding to the corrected color temperature value, . A display unit for displaying an image corresponding to a video signal provided from an external video signal source using white light; And And a light generating device formed under the display unit to generate the white light, The light- A plurality of image data, a plurality of luminance data corresponding to the plurality of image data is detected and output, a plurality of gradations corresponding to the plurality of image data are compared with a reference gradation, A luminance detector for outputting an enable signal; A dimming signal controller for receiving a correction signal and the brightness data and outputting a first dimming signal corresponding to the brightness data and a second dimming signal for correcting the first dimming signal based on the correction signal; A light source driver for outputting a driving signal in response to any one of the first and second dimming signals from the dimming signal controller; A light source unit including a plurality of light sources for generating white light in response to the driving signal; And And a light source corrector for starting driving in response to the enable signal and receiving the white light emitted from the light source and outputting the correction signal to correct the optical characteristics of the white light. 13. The method of claim 12, Wherein each of the plurality of light sources includes a red light emitting diode, a green light emitting diode, and a blue light emitting diode. 13. The image pickup apparatus according to claim 12, An enable signal generator for receiving the plurality of image data and generating and outputting the enable signal when a plurality of gradations corresponding to the plurality of image data are all greater than the reference gradation; And And a luminance data extracting unit for extracting luminance data from the image data. 13. The method of claim 12, And the optical characteristic of the white light is a luminance value. 13. The method of claim 12, Wherein the optical characteristic of the white light is any one of a color coordinate and a color temperature. 13. The method of claim 12, Wherein the reference gradation is a gradation corresponding to 1/2 of the entire gradation period. 18. The method of claim 17, Wherein the dimming signal controller outputs a dimming signal having a predetermined duty ratio if all of the plurality of image data are equal to or greater than the reference gray-scale level. A driving method of a light generating device including a plurality of light source units for generating white light in response to a driving signal, Receiving image data from outside; Extracting luminance data from the image data, and comparing the gradation of the image data with a reference gradation; Outputting a dimming signal selected from the first dimming signal corresponding to the brightness data and the second dimming signal corrected based on the comparison result; Generating the driving signal corresponding to one of the output dimming signals; And And outputting white light from the light source unit in response to the drive signal.

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