KR100225040B1 - Brightness compensation apparatus for projection tv - Google Patents

Abstract

The present invention is a device for correcting the difference in brightness between the center of the screen and the periphery of the projection TV is to enable a simple hardware configuration to uniformly correct the brightness of the entire screen.

Conventional brightness compensators for TVs compensate for the difference in brightness caused by the characteristics of the lens and the difference from each pixel on the screen to the CRT surface, but the deviation of the lens on the screen in each TV set and the optical path for each set The exact brightness distribution due to the differential cannot be known, or even when the correction waveform for the brightness distribution characteristic is used by the memory, the deviation for each TV set cannot be corrected.

In addition, there is a problem that when the correction waveform is made by the analog method, only the correction of the tendency of the lens characteristic and the light distribution of the light path is problematic.

According to the present invention, unlike the conventional method of calibrating the difference in brightness between the center and the periphery of the screen using a camera and a computer used for the automatic adjustment of the deflection without complicated hardware configuration, it is related to the lens, CRT, and optical path deviation of each TV set. It is a device that makes the brightness of all screen areas uniform.

Description

Peripheral Brightness Compensator for Projection TV

The present invention relates to a device for compensating the brightness difference between the screen center and the periphery of a projection TV, and relates to a device for compensating the brightness of the periphery of a projection TV so that the brightness difference of the entire screen can be uniformed by a simple hardware (H / W) configuration.

As shown in FIG. 2, the configuration of the conventional brightness correction apparatus for the peripheral portion of the projection TV is as follows.

The R, G, B interface unit 1 which separates the R, G, B signals into R, G, B correction units 2a, 2b, 2c by the video signal R, G, B correction units (2a, 2b, 2c) for correcting each of the R, G, B signals separated by the R, G, B interface unit 1 with a symmetrical correction waveform, and the R And R, G, and B tubes 3a, 3b, and 3c each displaying R, G, and B signals corrected by the G, B correction units 2a, 2b, and 2c on the respective screens.

The peripheral brightness correction apparatus of the conventional projection TV configured as described above will be described with reference to FIGS. 1 and 2.

In projection TV, the light from the C, R, G and B tubes reaches the screen through the lens to form an image.

Here, when the light from the CPT passes through the image, the periphery of the lens is lower than the transmittance of the center of the lens, so that the periphery of the screen is darker than the center of the screen, and the distance from the periphery of the screen to each CRT is Because of the distance between the tubes, the brightness of the periphery is darker than the brightness of the center of the screen.

As shown in Fig. 1, when the light of the same brightness from each R, G, B CRT in the horizontal center reaches the screen through the lens, the further away from the center of the screen, the respective R, G, B The brightness of the periphery of the CRT is reduced, and the brightness distribution of R, G, B in the vertical center shows that the brightness of the periphery decreases.

Referring to FIG. 2, a peripheral correction apparatus for correcting that the peripheral portion falls from the center of the screen as described above is as follows.

The video signal is input to the R, G, and B interfaces 1 and separated into respective R, G, and B signals and applied to the R, G, and B correction units 2a, 2b, and 2c.

The R, G, and B correction units 2a, 2b, and 2c respectively display correction waveforms of signals in which the brightness distribution curve of the light and symmetrical signals shown in FIG. 1 are applied to the respective R, G, and B signals. The G, B signals are corrected and output to the respective R, G, and B tubes 3a, 3b, and 3c.

As described above, the brightness of the periphery and the center of the screen are equalized by correcting each signal by applying the correction waveform as a signal symmetrical to the brightness distribution curve of the light.

Here, the correction waveform may be made by using a horizontal parabola waveform of deflection or by using a waveform generator, and the data having the same distribution as the correction waveform is stored in a memory and used as the correction waveform.

The projection TV as described above uses a CRT tube of each of R, G, and B, so that the deflection adjustment is performed on each of the projection TVs. The configuration of the automatic deflection adjustment apparatus shown in FIG.

Coordinates of the R, G, and B patterns applied by the camera 11, and a camera 11 for allowing the external computer 12 to recognize the coordinates of the R, G, and B patterns reflected on the screen by an external object. Compares the reference coordinates with the external computer 12 for outputting the adjustment data to the microcomputer 13 of the TV, and the external computer 12 applies the coordinate data for each pattern to the memory 14 by the external computer 12. The digital / analog converter 16 converts the deflection correction amount by using the microcomputer 13, the memory 14 for storing the adjustment data applied by the microcomputer 13, and the deflection adjustment data stored by the memory 14. And a digital / analog converter 16 for converting a deflection correction amount applied by the deflection correction unit 15 into an analog signal and outputting it to a deflection amplifier. Amplify and convert the analog signal converted by the analog converter 16 The deflection amplifier 17 is configured to apply a current to the incense yoke to adjust the deflection.

Unexplained symbol I ² C is a bi-directional bus connecting an external computer with a TV microcomputer.

Looking at the operation of the automatic deflection control device configured as described above are as follows.

First, when the pattern coordinates of R, G, and B are applied to the external computer 12 through the camera 11, the external computer 12 compares the input pattern coordinates of the R, G, and B with the reference coordinates. After the difference is calculated, adjustment data based on the difference value is stored in the memory 14 through the microcomputer 13 of the TV so that the pattern coordinates and the reference coordinates on the screen coincide with each other.

Here, the external computer 12 is coupled in both directions by the microcomputer 13 of the TV and the ice square (I ² C).

When the deflection correction unit 15 applies the deflection correction amount to the digital / analog converter 16 using the value stored in the memory 14, the digital / analog converter 16 converts the digital signal into an analog signal. The conversion is applied to the deflection amplifier 17.

The deflection amplifier 17 amplifies the converted analog correction signal to flow a current through the deflection yoke to adjust the deflection.

In the conventional projection TV peripheral brightness correction device, the brightness distribution on the screen of each TV set is not accurately known due to lens deviation, optical path difference between each set, and when the correction waveform is made by analog method, There is a problem that the brightness distribution is only roughly corrected by the characteristics and the optical path, and the deviation of each TV set cannot be corrected even when using the correction waveform by identifying the brightness distribution characteristic, calculating the correction amount, and storing the correction amount in the memory.

In the present invention, the peripheral brightness correction device uses a camera and a computer used for the automatic adjustment of the deflection without complicated hardware configuration, and unlike the conventional method, the brightness difference of the center and the peripheral part of the screen is different from the lens, CRT, and optical path deviation of the TV set. Regardless of this, the brightness distribution of all screen areas is uniform.

1 is a view showing the brightness distribution according to the vertical, horizontal position of the conventional screen

2 is a view showing a peripheral brightness compensation device (horizontal direction) of a conventional screen

3 is a block diagram showing a conventional automatic deflection adjustment

Figure 4 is a block diagram of a peripheral brightness correction device of the present invention

5 is a view showing the screen brightness value at the adjustment point of the present invention;

6 is a flow chart showing the process of determining the brightness correction constant of the present invention green (G)

The configuration of the brightness correction apparatus for the peripheral portion of the projection TV of the present invention will be described with reference to FIG. 4.

The camera 21 detects the pattern coordinates and brightness information of each of R, G, and B and applies them to the external computer 22, and uses the pattern coordinates and brightness information of each of R, G, and B by the camera 21. After the deflection adjustment is performed, the external computer 22 outputs the difference in brightness of each pattern adjustment position to the microcomputer 23 of the TV, and the deflection information is outputted by the external computer 22 to the deflection memory 23 and the correction waveform. The microcomputer 23 output to the peripheral correction memory 26, the bias memory 24 for storing the deflection information applied by the microcomputer and applying it to the deflection processing unit 25, and the information stored in the deflection memory 24 A bias processing unit 25 for applying current to the deflection yoke by means of a current, a peripheral correction memory 26 for outputting a peripheral brightness correction amount using brightness information of each pixel read by the microcomputer 23, and the peripheral correction memory Analog signal stored in (26) The digital / analog converter 27 converts to R, G, and B correction units 29a, 29b, and 29c and outputs a correction waveform to the R, G, and B correction units. R, G, and B interface units 28 output to the B correction units 29a, 29b, and 29c, and R, G, and B signals separated by the R, G, and B interface units 28; R, G, and B correction units 29a, 29b, and 29c for receiving and correcting correction waveforms of the respective signals by the digital / analog converter 27, and the R, G, and B correction units 29a, 29b, and 29c. R, G and B CRTs 30a, 30b and 30c displayed on the screen by receiving respective R, G and B signals corrected by the "

The external computer 22 uses an automatic deflection correction calculation unit 22a for detecting a deflection correction amount for deflection adjustment using input information, and a brightness correction waveform of a peripheral portion using the brightness information for each deflection position after the deflection adjustment is completed. It is composed of a peripheral portion brightness correction amount calculating section 22b.

The present invention will be described with reference to FIGS. 4 to 6 with respect to the peripheral brightness correction device of the projection TV as follows.

First, when the brightness and pattern positions of R, G, and B are detected by the external computer 22 through the camera 21, the external computer 22 adjusts the deflection by using the signal detected through the camera 21. And a brightness correction constant.

First, the automatic deflection correction calculation unit 22A of the external computer 22 compares coordinates of each pattern of R, G, and B inputted through a camera with reference coordinates, and then detects adjustment data for calculating and matching a difference. .

In addition, the automatic peripheral brightness correction calculator 22B of the external computer 22 reads the brightness values for each position of the deflection-adjusted adjustment data separately for each of R, G, and B.

That is, as shown in FIG. 6, the brightness value of each position is represented by I _R (X, Y), I _G (X, Y), and I _B (X, Y). The brightness of the screen at the center of the screen is displayed as I _R (X ₀ , Y ₀ ), I _G (X ₀ , Y ₀ ), I _B (X ₀ , Y ₀ ), so that the brightness for each R, G, B position Will read the value.

After reading the brightness values of the R, G, and B positions as described above, the peripheral brightness correction calculator 22b adjusts the brightness of the screen peripheral part and the brightness of the center of the screen.

At this time, when the brightness of the periphery of the screen is less than the brightness at the center of the screen, the image signal applied to the CRT is increased, and when the periphery of the screen is larger than the center of the screen, the brightness of the periphery of the screen and the brightness of the center are reduced. Since there is no difference, the brightness correction amount is detected.

In the external computer 22 that detects the deflection corrected adjustment data and the peripheral brightness correction amount detected as described above, the deflection corrected adjustment data through the microcomputer 23 of the TV connected to the Isquare C (I ² C) is stored in the deflection memory ( 24, and the peripheral brightness correction amount is stored in the peripheral correction memory 26 through the microcomputer 23 of the TV.

By using the value stored in the deflection memory 24 through the microcomputer 23 of the TV, the deflection processor 25 applies deflection current to the deflection yoke to adjust deflection.

Then, the peripheral brightness correction amount of each of R, G, and B stored in the peripheral correction memory 26 through the microcomputer 23 of the TV is converted into an analog signal by the digital / analog converter 27, and the respective R, G And B brightness correction constants ((α _R , α _G , α _B ) are output to the respective R, G, and B correction units 29a, 29b, and 29c.

On the other hand, when an image signal is applied to the R, G, B interface unit 28, the R, G, B interface unit 28 separates each of the separated R, G, B signals into R, G, B correction units ( 29a, 29b, and 29c.

The R, G, and B correction units 29a, 29b, and 29c are respectively applied by the digital / analog converter 27 to respective R, G, and B signals applied by the R, G, and B interface units 28, respectively. The R, G, B brightness correction constants (α _R , α _G , α _B ) are multiplied, and each of the R, G, B signals and the R, G, B brightness correction constants is a signal (α _R R , α _G G, α _B B) is output to the respective R, G, B CRTs 30a, 30b, and 30c to make the brightness of the periphery and the center of the screen uniform.

FIG. 7 is a flowchart showing a process of determining a brightness correction constant α _G for equalizing brightness of a C tube, for example, at the periphery of a CRT screen and a screen center. First, brightness correction constants at all adjustment points. Is the initial value α _G (X, Y) = 1.

Brightness I _G (X, Y), read the value of the brightness I _G from the center (X _0, Y ₀₎ of the first process of comparing a value, since the first process I _G (X _0, Y ₀ in a point ), If the difference is greater than the tolerance (ε), increase the brightness correction constant α _G (X, Y) by δ, read the I _G (X, Y) again, and repeat the comparison, and the tolerance (ε) If less, the second process of comparing the value of I _G (X, Y) and the value of I _G (X ₀ , Y ₀ ), and the value of I _G (X, Y) and I _G (X ₀ , If the difference comparing Y ₀ is greater than the tolerance (ε), decrease the value of α _G (X, Y) by δ and read α _G (X, Y) at this time and then read the value of I _G (X, Y). If the value is smaller than the tolerance ε, the process proceeds to the third process of finally storing the α _G (X, Y) value in the memory.

As described above, when the brightness of the periphery is less than the brightness of the screen center, the magnitude of the video signal applied to the CRT is increased, and when the brightness of the periphery is greater than the brightness of the screen center, By reducing the size, there is no difference between the brightness of the periphery of the screen and the brightness of the center of the screen.

In this case, many adjustment points can be used. However, when the number of adjustment points is large, a lot of memory is required and the calculation time is long.

That is, the pixels other than the adjustment point have the brightness correction constant α of the adjustment point closest to each pixel, thereby making the brightness of the entire screen uniform regardless of lens deviation and optical path deviation for each set.

As described above, the present invention can correct peripheral brightness with a simple hardware configuration using a conventional deflection control device, and has the effect of making the brightness of the entire screen uniform regardless of lens deviation and optical path deviation for each TV set. have.

Claims (2)

A camera that detects information on a TV screen, an external computer that outputs the deflection and brightness adjustment information to the microcomputer using the information detected by the camera, and the deflection adjustment information by the external computer. And a deflection memory for applying a current to the deflection yoke based on information stored in the deflection memory; A peripheral brightness correction memory for storing brightness adjustment information by the microcomputer, a digital / analog converter for converting information stored in the peripheral brightness correction memory to an analog signal and outputting the analog signal to an R, G, and B correction part; An R, G, B interface unit for separating the video signal into R, G, B signals and outputting the R, G, B correction unit; R, G, and B signals, which are separated by the R, G, and B interface units, are multiplied and corrected by the respective R, G, and B brightness correction constants converted to analog by a digital / analog converter. Peripheral part of the projection TV, characterized in that consisting of a correction unit, and R, G, B CRT displayed on the screen by receiving the respective R, G, B signals corrected by the R, G, B correction unit Brightness compensator The method of claim 1, wherein the external computer compares the R, G, B pattern coordinates with the reference coordinates using the detected information, calculates a difference, and adjusts the deflection adjustment information so that the coordinates of the pattern on the screen match the reference coordinates. After comparing the output of the deflection correction operation unit and the brightness of each position of the adjustment pattern deflected by the deflection correction operation unit with the brightness value at one point and the brightness value at the center, the brightness value at one point for the difference is calculated and added to the center. Peripheral brightness correction device characterized in that it comprises a peripheral brightness correction operation unit for outputting the peripheral brightness information so that the brightness value at the same point as the brightness value at

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