KR20080019769A - Method and apparatus for compensation color temperature of image displaying device - Google Patents

Abstract

An apparatus and a method for compensating color temperature of a video display device are provided to return changed color temperature to an initial setup value automatically if the color temperature is changed from the initial setup value due to long time usage of the video display device. A sensor(790) senses current color temperature. A controller(770) outputs a control signal so as to perform color temperature compensation according to whether the color temperature sensed by the sensor is consistent with preset reference color temperature. A color temperature compensator(750) compensates color temperature according to the control signal of the controller.

Description

Apparatus and method for color temperature compensation of an image display device

1 is a cross-sectional view schematically showing an image display device according to the spirit of the present invention.

2 is a partially exploded perspective view of the optical engine of FIG. 1.

3 is an exploded perspective view of the optical engine of FIG.

4 is a schematic view showing an optical path of a typical image display device.

5 is a schematic diagram showing an optical path of an image display device according to the present invention;

6 is a view showing a general waveform change of the lamp in the image display device of the present invention.

7 is a block diagram of a color temperature compensation device of an image display device according to the present invention;

8 is a flowchart of a color temperature compensation method of an image display device according to the present invention;

<Explanation of symbols for the main parts of the drawings>

700: video display device 710: tuner 720: decoder

730: ADC 740: image processing unit 750: color temperature compensation unit

760: display unit 770: control unit 780: memory

790: sensor

The present invention relates to an image display device, and in detail, in order to prevent the color temperature of a lamp provided in the image display device from being changed as the usage period elapses, a color sensor periodically detects whether the color temperature changes and feeds it back. The present invention relates to a color temperature compensating device and method for an image display device to correct a color temperature of a lamp.

Recently, due to the limitation on the screen size of the display device, development of a large-screen, ultra-thin display device has been active, and development of a projection display system has become prominent.

In such projection display systems, the development and dissemination of projectors using liquid crystal display (LCD) or digital light processing (DLP) has been rapidly increasing, so that not only for presentations in schools, corporations and government offices, but also It is used for home theater in home.

The DLP projector passes high-brightness light generated by a lamp through a color wheel so that an image is reproduced through an optical element such as a DMD.

Conventional DLP projectors drive a lamp by providing a lamp current of a constant frequency to the lamp regardless of the type of image, the frequency of the lamp current affects the amount of light emitted from the lamp, The amount affects the color temperature, which in turn affects the overall color of the screen displayed by the DLP projector.

In other words, in the case of the DLP projector that sequentially displays an image using a color wheel, the amount of light emitted from the lamp varies according to the amount of change in the lamp, and the color temperature is determined according to the amount of light. In addition, the overall color of the screen displayed on the display device is affected by the color temperature. Therefore, in order to maintain a constant color of the screen, the color temperature must be kept constant.

However, the conventional image display apparatus is manufactured so that the color temperature cannot be adjusted after the product is shipped once the color temperature is set based on the state at the time of manufacture of the product.

In other words, the color temperature may be deformed if the user's operating state of the product is changed to some extent because a problem occurs in some parts while the user is using the product and the product is replaced, or an external impact is applied to the product. However, the conventional video display device has a problem that once the color temperature is initially set, it is impossible to change it or that expensive equipment should be put therein even if it is possible to change it.

Moreover, the surrounding environment of the place where the product is used, for example, temperature, humidity, altitude, vibration, etc. are different for each user, so the operation state of the image display device may be changed slightly for each of the use environments. Therefore, there is a possibility that the color temperature is changed.

However, since the conventional image display device is manufactured such that the color temperature set during manufacture of the product cannot be changed, there is a problem in that it is not possible to actively cope with the above-mentioned parts change or the diversity of product use environment. In addition, there is a problem that the color feeling the user is constantly changing, causing fatigue to the user's eyes and may cause discomfort during viewing.

The present invention has been proposed to solve the above problems, and when the color temperature is changed from the initial setting value by long-term use of the image display device, the changed color temperature is automatically returned to the initial setting value. It is an object of the present invention to provide a color temperature guarantee device and method.

In addition, by measuring the color temperature periodically with a light sensor to check whether the color temperature is changed, and to correct it when the color temperature changes, color temperature guarantee device and method of the image display device that does not require a separate color temperature correction in the product manufacturing process It is for the purpose of being provided.

In addition, the color temperature compensation device of the video display device to maintain a constant color temperature, by maintaining a constant color of the screen that the user views, thereby reducing the fatigue of the user's eyes, the discomfort of the viewer felt as the image quality changes It is an object to provide a method.

According to an aspect of the present invention, there is provided a color temperature compensation method of an image display device, the image display device comprising: driving the image display device when a power-on command is input; Measuring a color temperature of the image display device and comparing the measured color temperature with a previously stored reference color temperature; And adjusting the driving state of the image display device such that the color temperature is equal to the pre-stored reference color temperature when the color temperature needs to be compensated as a result of the comparison.

According to another aspect of the present invention, a method for compensating a color temperature of an image display device includes periodically measuring a color temperature at an off time of the image display device when the image display device is driven, and periodically measuring the measured color temperature and a stored reference color temperature. Compared and determined, the gain value of the RGB signal is adjusted to maintain a constant color temperature of the image display device according to the determination result.

On the other hand, the color temperature compensation apparatus of the image display device according to the present invention, the sensing unit for detecting the current color temperature; A control unit for outputting a control signal to perform color temperature compensation according to whether the color temperature detected by the detection unit and a preset reference color temperature match; And a color temperature compensator for compensating the color temperature according to the control signal of the controller.

According to another aspect, an apparatus for compensating a color temperature of an image display device according to another aspect includes an image display having an optical sensor and a memory, the apparatus comprising: a tuner configured to receive a broadcast signal; A decoder for decoding an image received by the tuner; An ADC for converting the decoded image into a digital signal; An image processor converting the digital signal converted by the ADC into an RGB signal that can be viewed by a user; A color temperature compensator for adjusting a gain value of the RGB signal converted by the image processor to compensate for the color temperature; A display unit displaying a color temperature compensated screen through the color temperature compensation unit; And a controller for transmitting a control command to the color temperature compensator to control the RGB signal according to whether the current color temperature measured by the optical sensor and the reference color temperature stored in the memory coincide with each other.

According to the present invention, since the color temperature of the image display device is automatically maintained constantly, there is an advantage that the screen of constant image quality is continuously displayed.

Hereinafter, with reference to the drawings will be described a specific embodiment of the present invention;

However, the spirit of the present invention is not limited to the embodiments presented, and those skilled in the art who understand the spirit of the present invention can easily add, change, delete, and add other embodiments included in the scope of the same idea. It may be suggested that the invention fall within the scope of the present invention.

Hereinafter, an image display device according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view schematically showing an image display device according to the spirit of the present invention.

Referring to FIG. 1, a projection system 1 according to the present invention includes a cabinet 2 forming an exterior, a screen 4 mounted on the front surface of the cabinet 2, and a bottom mounted on the cabinet 2. An optical engine unit 10 and a rearview mirror 3 mounted to the inner circumferential surface of the cabinet 2 to reflect the image emitted from the optical engine unit 10 to the screen 4 are included.

In detail, the image screen formed and projected by the optical engine unit 10 is reflected by the rearview mirror 30. The reflected image is extended and projected onto the screen 4 so that the image screen is recognized by the user.

Hereinafter, the structure and function of each part of the optical engine unit 10 will be described in more detail with reference to the accompanying drawings.

2 is a partially exploded perspective view of the optical engine of FIG. 1.

Referring to FIG. 2, the optical engine unit 10 according to the present invention may include a base 11, an optical engine 20 mounted on the base 11, and various types mounted on the outside of the optical engine 20. Parts are included.

In detail, a power supply unit 15 for supplying an appropriate amount of power to various electrical components constituting the optical engine unit 10 may be provided to various components mounted on the outside of the optical engine 20, and the power supply unit 15. A power supply supporter 16 for supporting the lamp, a lamp cooling fan assembly 14 for cooling a lamp (to be described later) constituting the optical engine 20, and a ballast 13 mounted to one side of the base 11. ), A projection lens cap 17 surrounding the projection lens (to be described later) constituting the optical engine 20, and a DMD fan 12 for cooling the DMD (to be described later) constituting the optical engine 20. ) Is included.

In more detail, the power supply unit 15 is a switching mode power supply (SMPS), and is a modular power supply device that converts electricity supplied from the outside to match the electric device. In addition, the power supply unit 15 controls the intermittent control at a high frequency of a commercial frequency or higher and mitigates the impact by using semiconductor switching characteristics.

In addition, the ballast 13 functions to apply a high voltage when the lamp constituting the optical engine 20 is turned on and to appropriately adjust the current so that an overcurrent does not flow after the lamp is turned on.

As shown in FIG. 2, in the case of the optical engine unit 10 according to the present invention, each part except the optical engine 20 may be independently separated from the base 11. Thus, the optical engine 20 is mounted to the base 11, and then each of the components mentioned above are coupled to the base 11.

3 is an exploded perspective view of the optical engine of FIG. 1.

Referring to FIG. 3, the optical engine 20 according to the present invention includes a lamp assembly 21 in which white light is generated by a high voltage supplied by the ballast 13, and unpolarized light emitted from the lamp assembly 21. A color wheel assembly 22 for separating the red, green, and blue, a light tunnel assembly 24 for uniformly making red, green, and blue separated light while passing through the color wheel assembly 22; A condensing lens 25 through which the uniform light is collected while passing through the light tunnel assembly 24, a folding mirror 29 reflecting light passing through the condensing lens 25, and A total reflection prism 30 for reflecting the light reflected by the folding mirror 29 again, a DMD assembly 26 for collecting the light reflected by the total reflection prism 30 to form image information, and the DMD assembly ( Reflected from 26 An actuator 27 for doubling and irradiating the number of pixels of light and a projection lens 31 for enlarging the light passing through the actuator 27 are included. Here, the assembly of the lamp assembly 21, the color wheel assembly 22, the light tunnel assembly 24 and the condensing lens 25 is called an illumination system. The aggregate of the folding mirror 29 and the total reflection prism 30 is called a reflectometer, and the aggregate of the reflectometer and the DMD assembly 26 is called a synthetic system.

In more detail, the lamp assembly 21 includes a lamp 212 that emits white light and a lamp case 211 that protects the lamp 212. In addition, the reflector of the lamp 212 serves to change the light emitted from the burner of the lamp is reflected to focus at a certain distance, that is, the focal length.

In addition, the color wheel assembly 22 may be divided into red, green, and blue color wheels (also referred to as 221: RGB color filters) and rotate at high speed. A motor 223 driving the wheel 221 and a heat dissipation fin 222 for cooling the motor 223.

In detail, light emitted from the lamp 212 by the reflector of the lamp 212 is focused on the surface of the color wheel 221. In addition, the light collected by the color wheel 221 passes through the color wheel 221 and turns any color of red, blue, and green. Here, the color wheel 221 has a disk shape having a predetermined diameter, the disk is divided into red, green, blue. Accordingly, the unpolarized light reflected by the reflector has one of red, blue, and green colors due to the color of the color wheel located at the moment of condensing.

In addition, the color wheel assembly 22 and the light tunnel assembly 24 are housed inside the light tunnel housing 23.

In addition, the light tunnel assembly 24 is also called a rod lens, and serves to uniformly make colored light passing through the color wheel 221.

In detail, the light tunnel assembly 24 is formed by joining four small, long rectangular bar mirrors facing each other. The light passing through the color wheel assembly 22 is diffusely reflected while passing through the light tunnel, and the brightness distribution is uniform.

In addition, the condensing lens 25 performs a function of collecting red, green, and blue light uniformed while passing through the light tunnel assembly 24 to the DMD elements constituting the DMD assembly 26. do.

The total reflection prism 30 may also be referred to as a total internal reflection (TIR) prism, and a prism having a large refractive index and a prism having a relatively small refractive index are bonded to each other. And, due to the difference in refractive index is totally reflected or transmitted according to the incident angle of the light irradiated from the condensing lens 25.

In detail, each object has its own refractive index, and the difference in refractive index determines the critical angle at which light is totally reflected or transmitted.

Therefore, light incident at an angle greater than or equal to a critical angle is totally reflected by the total reflection prism 30, and light incident at an angle smaller than or equal to a critical angle passes through the total reflection prism 30. The function of the total reflection prism 30 will be described in detail with reference to the accompanying drawings.

In addition, the DMD assembly (Digital Micro-mirror Device Assembly) 26 is composed of a DMD panel 33 and a driver board in which the DMD panel 33 is accommodated. In detail, the driver board is a device for controlling the driving of the ballast and the color wheel or controlling the image.

On the other hand, the DMD panel 33 is designed so that a minute mirror of the same amount as the resolution of the display is arranged so as to have a one-to-one correspondence with the screen.

In detail, the DMD panel 33 determines whether the red, green, and blue light transmitted through the total reflection prism 30 is to be directed toward the screen or discarded out of the screen. The DMD panel 33 is mounted in a complementary metal oxide semiconductor (CMOS) memory and driven by a signal transmitted from the CMOS memory.

In more detail, the micromirror constituting the DMD panel 33 is manufactured in the form of a fine diamond-shaped pixel of 16 μm in width and length, and tilted by ± 10 degrees according to a signal transmitted from the CMOS, so that the total reflection prism ( Light passing through 30 is reflected to the screen group or is thrown out of the screen.

In addition, the actuator 27 is disposed between the DMD panel 33 and the projection lens 31, and a mirror is mounted at the center portion. In detail, the actuator 27 performs a function of doubling the number of pixels of the image signal by refracting and dividing the image signal emitted from the DMD panel 33 by half a frame. Due to the refraction characteristics of the mirror, the resolution of the screen is increased. In addition, the actuator includes a transmission type and a reflection type.

In addition, the projection lens assembly 31 functions to enlarge the image passing through the actuator 27 toward the rearview mirror 3.

In the optical engine 20 having the above-described configuration, the actuator 27, the total reflection prism 30, and the folding mirror 29 are inserted from different surfaces of the reflector case 28 so that one reflectometer may be used. Configure. The color wheel assembly 22 and the light tunnel assembly 24 are accommodated in the light tunnel housing 23 to constitute another assembly. In addition, the lamp assembly 21 forms a separate assembly together with the lamp 212 mounted inside the lamp case 211, and the light tunnel housing 23 is in close contact with the front of the lamp assembly 21. do.

By the above configuration, the projection system is normally driven and the screen is displayed to the user.

4 is a schematic diagram illustrating an optical path of a general image display device.

Referring to FIG. 4, in the conventional image display apparatus, the light generated by the lamp 212 is projected toward the projection lens 31 by the DMD panel 33 or discarded out of the screen.

In detail, the operation principle of the lamp 212 is as follows.

First, discharge is started at the electrode in the burner of the lamp by supplying a high voltage (+/- 25 kV) for initial startup from a ballast supplying a starting voltage to the lamp. As the mercury gas is activated by the discharge and the temperature inside the burner is increased, the mercury gas is further activated to increase the amount of light. After about 90 seconds, the light reaches 80% of the normal brightness.

When the initial high voltage is applied and ignited, the impedance of the lamp 212 begins to decrease, the voltage starts to rise from several V, the current starts to decrease from several A, and when stabilized, AC 85V (90 Hz), 1.2A current flows in stable operation.

Here, the color temperature compensation device of the image display device according to the present invention is proposed to correct the change in the color temperature according to the long-term use of the image display device. That is, when the image display device is used for a long time or when some parts are replaced, the amount of light and the color temperature thereof change, and thus, the user feels the color. Therefore, in order to maintain the color of the screen viewed by the user, the light discarded by the lamp 212 is collected, and the driving state of the lamp 212 is adjusted to maintain the predetermined reference value. .

Here, the color temperature is a method of numerically displaying the light of the light source.

In detail, the color of light emitted by an ideal blackbody is determined only by temperature according to Planck's law of radiation. When an object is shining with visible light and its color looks like the color of a black body of any temperature, the temperature of the black body and the object's temperature are considered to be the same and the temperature is called the color temperature of the object. That is, the color temperature of the object is represented by the temperature (absolute temperature K) of the black body of the same color light.

For example, the light of the bulb is 2,800K, the fluorescent light is 4,500 ~ 6,500K, the noon sun light is 5,400K, the cloudy daytime light is 6500 ~ 7000K, and the clear blue sky is about 12,000 ~ 18,000K. Color temperature. Color temperature measurements are established internationally and are measured using suitable colored glass filters and standard light sources.

On the other hand, the color means a feeling received from the color. In general, the color is measured based on which color is felt as white. The color may be different from each other depending on the region of use and the environment of use of the image display device. In other words, users of a country may feel that a blue-white white is closer to white, and users of a country may be more red-white. Therefore, the color temperatures that the user feels to be white may be different from each other. In Korea, when the color temperature is generally 9300K, it is called white light.

On the other hand, the operation principle of the DMD panel 33 is as follows.

The DMD panel 33 is designed such that a minute mirror of the same amount as the resolution of the display is arranged so as to have a one-to-one correspondence with the screen. In addition, the DMD panel 33 determines whether the red, green, and blue light transmitted through the total reflection prism 30 is emitted toward the screen or discarded out of the screen.

More specifically, the micro mirror constituting the DMD panel 33 is manufactured in the form of a fine diamond-shaped pixel of 16 μm in width and width, and is tilted by ± 10 degrees according to a signal transmitted from a complementary metal oxide semiconductor (CMOS). Light passing through the total reflection prism 30 is reflected toward the screen or thrown out of the screen.

Here, the light reflected toward the screen passes through the projection lens 31 to implement an image on the screen, and the light discarded out of the screen is absorbed by the light absorber 41 and discharged to the outside. That is, in the conventional image display apparatus as described above, the light discarded by the DMD panel 33 is discharged to the outside as waste heat and discarded without any role.

FIG. 5 is a schematic view showing an optical path of an image display device according to the present invention, and FIG. 6 is a view showing a general waveform change of a lamp in the image display device of the present invention.

Referring to FIG. 5, in the image display device according to the present invention, the light generated by the lamp 212 is projected toward the projection lens 31 when the DMD panel 33 is turned on, whereas the DMD panel 33 Is turned off, it is projected toward the optical sensor 42. Then, the light projected toward the optical sensor 42 is collected by the optical sensor 42 to detect whether or not the color temperature is changed, and when the result of the detection requires compensation of the color temperature, an analog digital converter (ADC) 43 and an image are required. The color temperature is corrected by the processor 44 and displayed on the screen.

Meanwhile, the general waveform change of the lamp in the image display device is shown in FIG. 6. Referring to FIG. 6, the light emitted from the lamp 212 is focused on the surface of the color wheel (see 221 of FIG. 3) which is divided into red / green / blue and rotates at high speed. In addition, the unpolarized light emitted from the lamp 212 may have any color of red / blue / green due to the color of the color wheel located at the moment of condensing. That is, the lights of the red 630, the green 620, and the blue 610 are repeatedly displayed as shown in FIG. 6.

At this time, in the middle of the cycle in which the red, blue, and green are repeated, there is an off time 640 in which no light is emitted every certain period. That is, there is an area where light emitted from the lamp 212 and incident on the DMD panel 33 is reflected as it is incident and transmitted to the optical sensor 42.

In the present invention, the color temperature is compensated for by using the light in the off time region 640. In other words, since the light emitted from the off-time 640 region is a region in which light emitted from the lamp is incident on the optical sensor 42 without loss, the light of the off-time 640 region becomes white light. Therefore, the color temperature of the light incident on the off-time 640 is measured by the optical sensor 42, by calculating how the measured color temperature is changed from the reference value to compensate for this, so that a constant color temperature can be maintained at all times It is.

7 is a block diagram of a color temperature compensation device of an image display device according to the present invention. Here, the color temperature compensation device of the image display device will be described using the case of a TV as an example, but it will be obvious that the present invention is generally applicable to a display device using a reflective panel instead of only a projection TV.

Referring to FIG. 7, the image display device includes a tuner 710 for receiving a broadcast signal, a decoder 720 for decoding an image received from the tuner 710, and an ADC for converting the decoded image into a digital signal. 730, an image processor 740 that receives the digital signal converted by the ADC 730 and converts the signal into an " RGB " signal that can be viewed by the user, and the " RGB " signal of the image converted by the image processor 740. A color temperature compensator 750 for adjusting a gain value, a display unit 760 on which a color temperature compensated screen is displayed by the color temperature compensator 750, and controlling the process as a whole and correcting the color temperature A control unit 770 which transmits a control command for performing correction of an "RGB" signal to the color temperature compensator 750, various data and processing programs are stored, and a reference value for color compensation according to a lamp driving state is stored. Includes a memory 780 and a sensor 790 that detects a current color temperature and transmits the detected color temperature to the controller 770.

In detail, when the current color temperature measured by the sensor 790 does not match the reference color temperature stored in the memory 780, it is necessary to correct the color temperature by adjusting the gain value of the "RGB" signal.

Here, a PWM method is used to adjust the color temperature.

PWM (pulse width modulation), also known as pulse width modulation, is one of the pulse modulation method, a method of modulating by changing the width of the pulse in accordance with the size of the modulation signal. In other words, when the amplitude of the signal wave is large, the width of the pulse becomes wider, and when the amplitude of the signal wave is small, the width of the pulse becomes narrow. However, the position and amplitude of the pulse do not change.

In the image display device of the present invention, color is adjusted using the PWM method. That is, image quality is compensated by adjusting whether the DMD panel (see 33 in FIG. 5) is turned on or off and the on / off speed.

In detail, when the respective colors are fully turned off in the DMD panel (see 33 of FIG. 5), that is, light flowing into the optical sensor (see 42 of FIG. 5) in the off time (see 640 of FIG. 6) is RGBYCM. (888888), and this is white light (R + G + B + Y + C + M = White).

By the way, when the color temperature of the lamp changes due to the long time of use of the lamp, the amount of light emitted by the wavelength band of the lamp changes, and the color temperature at this time is different from the color temperature in the reference state.

In this case, to adjust the color temperature, adjust the gain amount of each color. For example, if the green light is too high and the color temperature is 6000K, lower the green light, that is, adjust the on / off speed of the DMD panel when the light emitted from the lamp passes the green area of the color wheel. Adjust to 9300K. RGBYCM (888888-> 848888)

In other words, the amount of gain of each color is adjusted to maintain a constant color temperature.

According to the configuration described above, by measuring the color temperature periodically by measuring the color temperature with an optical sensor to check whether the color temperature changes, and to correct it when changing the color temperature, there is an advantage that a separate color temperature correction is unnecessary in the product manufacturing process. .

With reference to the above-described structure will be described in more detail the operation to action according to the present invention.

First, when the power on button of the image display apparatus 700 is input by a user, the image display apparatus 700 starts to be driven.

When the image display apparatus 700 is driven, the color temperature of the off time is periodically measured by the sensor 790 and transmitted to the controller 770.

In addition, the controller 770 compares the value of the reference color temperature stored in the memory 780 with the value of the color temperature in the off time measured by the sensor 790 to determine whether the correction of the color temperature is necessary.

As a result of the determination, if the color temperature of the off time is different from the reference value, the controller 770 controls the color temperature compensator 750 to correct the color temperature by the PWM method.

In the above manner, by periodically measuring the color temperature of the image display device 700 is changed from the reference value and correcting it, there is an advantage that the user can continuously watch the screen of a certain color sense.

8 is a flowchart illustrating a color temperature compensation method of an image display device according to the present invention.

First, when a power-on button of the image display device 700 is input by a user, the image display device 700 starts to be driven. (Steps S810 to S820).

When the image display apparatus 700 is driven, the color temperature of the off time is periodically measured by the sensor 790 and transmitted to the control unit 770 (step S830).

In detail, when the image display apparatus 700 is driven, the light emitted from the lamp is projected toward the projection lens by the DMD panel or discarded out of the screen. Here, the light emitted from the lamp is concentrated on the surface of the color wheel divided into red, green, and blue, so that any color of red, blue, or green may be caused by the color of the color wheel located at the moment of condensing. do. At this time, in the middle of the cycle in which the red, blue, and green are repeated, there is an off time in which no light is emitted every certain period. That is, there is an area where light emitted from the lamp and incident on the DMD panel is reflected as it is incident and transmitted to the optical sensor.

Since the light in the off-time area is an area in which the light emitted from the lamp is incident to the sensor 790 without loss, the light in the off-time area is immediately white light. Thus, the off-time color temperature is used as a comparison object for determining whether the current color temperature is changed compared to the color temperature of the reference state.

Next, the off-time color temperature transmitted to the control unit 770 is compared with the reference color temperature (for example, 9300K) stored in the memory 780 by the control unit, and the difference between the measured color temperatures of the reference color temperature. Is generated, and if a difference occurs, it is determined how long it has occurred. (S840 to S850).

As a result of the determination, if a difference occurs between the measured color temperature and the reference color temperature, the controller adjusts a gain value of the "RGB" signal so that the color temperature is corrected to the reference value (step S860).

And, until the image display device is powered off (step S870), the step S830 or less is periodically repeated to adjust the color temperature of the lamp to maintain a constant reference value, thereby maintaining the color of the screen.

According to the apparatus and method for compensating the color temperature of an image display device according to the present invention, when the color temperature is changed from an initial setting value by long-term use of the image display device, the changed color temperature is automatically returned to the initial setting value. An apparatus and method for guaranteeing color temperature of a display device are provided.

In addition, by using the waste heat of the off-time area discarded in the DMD panel to perform color temperature compensation, there is an advantage that the recycling of resources can be implemented.

In addition, by having a light sensor to periodically check the color temperature while checking the color temperature change, and to correct it when the color temperature changes, there is an effect that a separate color temperature correction is unnecessary in the product manufacturing process.

In addition, since the color temperature is kept constant, the color of the screen viewed by the user is kept constant, thereby reducing the fatigue of the user's eyes and reducing the discomfort of the viewer felt as the image quality is changed.

Claims (13)

In the video display device, A detector for detecting a current color temperature; A control unit for outputting a control signal to perform color temperature compensation according to whether the color temperature detected by the detection unit and a preset reference color temperature match; And, And a color temperature compensator for compensating the color temperature according to the control signal of the controller. The method of claim 1, The sensing unit is a color temperature compensation device of a video display device, characterized in that the color temperature is detected at a predetermined period. The method of claim 1, And a memory in which the preset reference color temperature is stored. The method of claim 1, Color temperature compensation apparatus of the image display device, characterized in that the color temperature compensation is performed by the PWM method in the color temperature compensation unit. The method of claim 1, And the sensing unit is configured as an optical sensor. In the image display with an optical sensor and a memory, A tuner for receiving a broadcast signal; A decoder for decoding an image received by the tuner; An ADC for converting the decoded image into a digital signal; An image processor converting the digital signal converted by the ADC into an RGB signal that can be viewed by a user; A color temperature compensator for adjusting a gain value of the RGB signal converted by the image processor to compensate for the color temperature; A display unit displaying a color temperature compensated screen through the color temperature compensation unit; And And a controller configured to transmit a control command to the color temperature compensator to control the RGB signal according to whether the current color temperature measured by the optical sensor and the reference color temperature stored in the memory coincide with each other. Device color temperature compensation device. The method of claim 6, And a color temperature detected by the optical sensor is a color temperature at off time. The method of claim 6, And color temperature compensation by adjusting an on / off speed of a panel provided in the image display device such that the color temperature is maintained at a predetermined reference value through the color temperature compensator. In the video display device, Driving the image display device when a power-on command is input; Measuring a color temperature of the image display device and comparing the measured color temperature with a previously stored reference color temperature; And, And adjusting a driving state of the image display device such that a color temperature is equal to the pre-stored reference color temperature when the color temperature needs to be compensated as a result of the comparison. The method of claim 9, The measured color temperature is a color temperature in the off time color temperature compensation method of the image display device. The method of claim 9, And the previously stored reference color temperature is a color temperature of white light. The method of claim 9, And adjusting the driving state of the image display device such that the color temperature is equal to a pre-stored reference color temperature by a PWM method. When the image display device is driven, the color temperature at the off time of the image display device is periodically measured, and the measured color temperature and the stored reference color temperature are periodically compared and determined, and the color temperature of the image display device is determined according to the determination result. The gain value of the RGB signal is adjusted so that it is kept constant.

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