JPH0937280A - Shading correction circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the uniformity of white color of the entire screen and the uniformity of luminance in a projection television receiver. SOLUTION: The circuit is made up of color temperature sensors 1-7, a CPU 8 comparing a measured value from each color temperature sensor with an objective value so as to discriminate the uniformity of white color to generate a control signal controlling a waveform generating circuit 1 based on the result of discrimination, a waveform generating circuit 11 receiving the control signal from the CPU 8 and H, V pulses synchronously with a horizontal synchronizing signal and a vertical synchronizing signal to generate two kinds of optical waveforms by one field synchronously with the horizontal synchronizing signal and the vertical synchronizing signal, a memory 9 storing the control signal from the CPU 8 and a modulation circuit 12 modulating primary red, blue color signals with the waveform generated from the waveform generating circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correction circuit for improving the performance of white uniformity and brightness uniformity of the entire screen of a television receiver or the like.

[0002]

2. Description of the Related Art In recent years, the performance of television receivers has improved, and the demand for larger and wider screen sizes has increased. The projection television is an effective means for realizing the above two flows. However, the projection-type television is inferior to the direct-view television in the performance of white uniformity and luminance uniformity of the entire screen, which is a big problem in performance. The main cause of the problem is the difference in the projection distance and the trapezoidal distortion that occur because the CRTs of red, blue, and green are arranged in one row in the CRT method. Non-uniformity occurs. Further, in the liquid crystal system, the transmittance is uneven in the liquid crystal panel, which causes irregular white nonuniformity.

As a conventional countermeasure method, in the CRT method, a part of the projection lens attached to each of the red, blue, and green CRTs is covered with a sheet so that white is most uniform.
Further, in the liquid crystal method, improving the performance of the liquid crystal panel was a fundamental measure.

[0004]

[Problems to be Solved by the Invention] However, the above-mentioned CRT
In the method of the method, since the lens surface is covered with the sheet, there is an adverse effect that the brightness is reduced. Also, it was difficult to absorb variations between sets. In the above liquid crystal method, the performance of the set depends on the performance of the liquid crystal panel.

Therefore, it is an object of the present invention to improve the performance of the uniformity of white and the uniformity of brightness of the entire screen of a television receiver or the like by correction by an electric circuit, and solve the above problems. .

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the means of the present invention uses an H signal synchronized with a horizontal / vertical synchronizing signal.
A signal generating circuit for generating an arbitrary waveform for one field by a pulse and V pulse and an external control signal, a memory for storing the control signal, and primary, red, blue and green primary color signals are generated by the signal generating circuit. A modulation circuit that modulates with an arbitrary waveform, a plurality of color temperature sensors installed on the screen for detecting white balance, and the signal generation circuit so that the detection value from the color temperature sensor becomes an arbitrary value. And a CPU for controlling the.

[0007]

According to the present invention, the color temperature sensor for detecting a plurality of white balances is installed on the screen, the color temperature at each sensor position is measured, and each measured value data is controlled by the signal generating circuit. The difference between the measured color temperature value and the target color temperature value is calculated and compared with a predetermined value in consideration of measurement error and variations, and the difference between each measured value and the target color temperature value is a predetermined value or more. It is determined that the white on the screen is not uniform. If it is determined that the white on the screen is not uniform, red, blue, and green are used to bring the color temperature of the place where the difference between the measured value and the target color temperature value is equal to or more than the specified value closer to the target value. The CPU controls the modulation signals which are respectively modulating the primary color signals, and changes the drive ratio of red, blue, and green at that location. By repeating these operations, it is possible to improve the white uniformity of the entire screen.

[0008]

【Example】

(Embodiment 1) First, a first embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, color temperature sensors 1 to 7 are installed to receive the all-white signal when adjusting the set of a three-tube rear-projection TV, and to detect white balance on the screen center and on the left and right sides of the screen. To be done. The color temperature at each position on the screen is measured by each color temperature sensor, and each measured value data is stored in the CPU 8 outside the set.
Is transmitted to

The CPU 8 obtains the difference between the measured value of the color temperature sensor 1 and the measured values of the other color temperature sensors 2 to 7, and compares the difference with a predetermined value in consideration of measurement error and variations, and the difference is a predetermined value. When it is above, it is determined that the white on the screen is not uniform. For example, color temperature sensors 3-7
The difference between the measured value of the color temperature sensor 1 and the measured value of the color temperature sensor 1 is within a predetermined value, but when the difference between the measured value of the color temperature sensor 2 and the measured value of the color temperature sensor 1 is equal to or more than the predetermined value, It is determined that the white of the position of the sensor 2 is not uniform.

Subsequently, the CPU 8 generates a control signal for controlling the waveform generating circuit 11 in the set based on the determination data, and transmits the control signal to the microcomputer 9, the memory 10 and the waveform generating circuit 11 in the set. In the waveform generating circuit 11, by inputting an H pulse synchronized with a horizontal synchronizing signal, a V pulse synchronized with a vertical synchronizing signal, and a control signal from the external CPU 8, two red and blue synchronized horizontally and vertically are provided. An arbitrary waveform for one field is generated and input to the modulation circuit 12.

In the modulation circuit 12, the primary color signal is modulated by an arbitrary waveform generated by the waveform generation circuit 11, and the drive ratio of a part of red, blue and green on the screen is changed. For example, when it is determined that the white color at the position of the color temperature sensor 2 is not uniform, the CPU 8 determines whether the red color is insufficient, the blue color is insufficient, or the red color is large, based on the determination data. It is determined whether there are many.

For example, when the amount of red is large and the amount of blue is insufficient, the CPU 8 controls the waveform generating circuit 11 to generate a modulation waveform that lowers the red drive and increases the blue drive.
Generate a control signal from. The transmitted control signal is stored in the memory 10 and continues to generate the waveform set by the waveform generating circuit 11 even if the CPU 8 is removed. By repeating these operations, it is possible to improve the white uniformity of the entire screen.

(Embodiment 2) Next, a second embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, when a three-tube rear-projection television set is adjusted, an all-white signal is received and a total of 7 signals are displayed on the screen center and left and right.
Luminance sensors 13 to 19 that detect the luminance are installed at the locations. The brightness of each position on the screen is measured by each brightness sensor, and each measured value data is stored in the CPU 20 outside the set.
Is transmitted to

The CPU 20 obtains the difference between the measured value of the brightness sensor 13 and the measured values of the other brightness sensors 14 to 19, and compares the difference with a predetermined value in consideration of measurement error and variations. If so, it is determined that the brightness on the screen is not uniform. For example, the brightness sensor 15
The difference between the measured values of ˜19 and the measured value of the brightness sensor 13 is within a predetermined value, but when the difference between the measured value of the brightness sensor 14 and the measured value of the brightness sensor 13 is equal to or more than the predetermined value, the brightness sensor 14 It is determined that the luminance at the positions of is not uniform.

Subsequently, the CPU 20 generates a control signal for controlling the waveform generating circuit 23 in the set based on the determination data, and transmits the control signal to the microcomputer 21, the memory 22 and the waveform generating circuit 23 in the set. In the waveform generating circuit 23, by inputting an H pulse synchronized with a horizontal synchronizing signal, a V pulse synchronized with a vertical synchronizing signal, and a control signal from the outside, an arbitrary waveform for one field synchronized horizontally and vertically is obtained. Is generated and input to the modulation circuit 24.

In the modulation circuit 24, the luminance signal is modulated by the arbitrary waveform generated by the waveform generation circuit 23, and the drive amount of a part of the screen is changed. For example, the brightness sensor 1
When it is determined that the luminance at the position of 4 is non-uniform, CP
Based on the determination data, U20 determines whether there are insufficient drives or there are many drives. For example, when the drive is insufficient, the control signal is generated so that the waveform generation circuit 23 generates a modulation waveform that increases the drive amount.

The transmitted control signal is stored in the memory 22, and the waveform set in the waveform generating circuit 23 continues to be generated even if the CPU 20 is removed. By repeating these operations, it is possible to improve the uniformity of the brightness of the entire screen.

(Embodiment 3) Next, a third embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 3, when a set adjustment of a three-tube rear projection type television is received, an all-white signal is received, and a total of 7 signals at the center of the screen and at the left and right sides are received.
Luminance sensors 25 to 31 for detecting the luminance are installed at the locations. The brightness at each position on the screen is measured by each brightness sensor, and each measured value data is stored in the CPU 32 outside the set.
Is transmitted to

The CPU 32 obtains the difference between the measured value of the brightness sensor 25 and the measured values of the other brightness sensors 26 to 31, and compares the difference with a predetermined value in consideration of measurement error and variations. If so, it is determined that the brightness on the screen is not uniform. For example, the brightness sensor 27
The difference between the measured value of ~ 31 and the measured value of the brightness sensor 25 is within a predetermined value, but when the difference between the measured value of the brightness sensor 26 and the measured value of the brightness sensor 25 is equal to or more than the predetermined value, the brightness sensor 26 It is determined that the luminance at the positions of is not uniform.

Then, the CPU 32 generates a control signal for controlling the waveform generating circuit 35 in the set based on the determination data, and transmits the control signal to the microcomputer 33, the memory 34 and the waveform generating circuit 35 in the set.

In the waveform generation circuit 35, by inputting an H pulse synchronized with a horizontal synchronizing signal, a V pulse synchronized with a vertical synchronizing signal, and a control signal from the outside, red, blue, and blue synchronized with the horizontal and vertical signals are inputted. Arbitrary waveforms for one green field are generated and input to the modulation circuit 36. In the modulation circuit 36, the primary color signal is modulated by an arbitrary waveform generated by the waveform generation circuit 35, and the drive amounts of red, blue, and green on a part of the screen are changed. For example, when it is determined that the brightness of the position of the brightness sensor 26 is not uniform, the CPU 32
Then, based on the determination data, it is determined whether the number of drives is insufficient or the number of drives is large. For example, when the drive is insufficient, a control signal is generated so that the waveform generation circuit 35 generates a modulation waveform that increases the drive amounts of red, blue and green.

The transmitted control signal is stored in the memory 34, and the waveform set in the waveform generating circuit 35 continues to be generated even if the CPU 32 is removed. By repeating these operations, it is possible to improve the brightness uniformity of the entire screen without changing the brightness signal level.

(Fourth Embodiment) Next, a fourth embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 4, when a set adjustment of a three-tube rear projection type TV is performed, an all-white signal is received and a total of 7 signals are displayed on the screen center and left and right.
Sensors 37 to 43 for detecting brightness and color temperature at a location
Is installed. The brightness and color temperature of each position on the screen are measured by each sensor, and each measured value data is transmitted to the CPU 44 outside the set.

The CPU 44 obtains the difference between the measurement value of the sensor 37 and the measurement values of the other sensors 38 to 43, and compares the difference with a predetermined value in consideration of measurement error and variations.
If the difference between them is greater than or equal to a predetermined value, it is determined that the brightness and white on the screen are not uniform. For example, the sensor 40-
The difference between the measured value of 43 and the measured value of the sensor 37 is within a predetermined value, but the measured value of the brightness of the sensor 38 and the sensor 3
When the difference between the measured luminance values of 7 is a predetermined value or more, it is determined that the luminance at the position of the sensor 38 is non-uniform, and the difference between the measured color temperature of the sensor 39 and the measured value of the color temperature of the sensor 37. Is greater than or equal to a predetermined value, it is determined that the white at the position of the sensor 39 is not uniform.

Subsequently, the CPU 44 generates a control signal for controlling the waveform generating circuit 47 in the set based on the determination data and transmits the control signal to the microcomputer 45, the memory 46 and the waveform generating circuit 47 in the set.

In the waveform generating circuit 47, by inputting an H pulse synchronized with a horizontal synchronizing signal, a V pulse synchronized with a vertical synchronizing signal, and a control signal from the outside, red, blue, and blue synchronized with the horizontal and vertical signals are inputted. Arbitrary waveforms for three green fields are generated and input to the modulation circuit 48.

In the modulation circuit 48, the primary color signal is modulated by an arbitrary waveform generated by the waveform generation circuit 47, and the drive amount of a part of red, blue and green on the screen is changed. For example, when it is determined that the brightness of the position of the brightness sensor 38 is non-uniform, the CPU 44 determines whether the number of drives is insufficient or the number of drives is large based on the determination data. For example, if there are insufficient drives, red, blue,
A control signal is generated so that the waveform generation circuit 35 generates a modulation waveform that increases the green drive amount.

If it is determined that the white position of the sensor 39 is not uniform, the CPU 44 determines whether red is insufficient or blue is insufficient based on the determination data.
It is determined whether there is much red or blue. For example, when the amount of red is large and the amount of blue is insufficient, the control signal is generated so that the waveform generation circuit 47 generates a modulation waveform that lowers the drive of red and raises the drive of blue.

The control signal thus transmitted is stored in the memory 46, and the waveform set in the waveform generating circuit 47 continues to be generated even if the CPU 44 is removed. By repeating these operations, it is possible to simultaneously improve the brightness of the entire screen and the uniformity of white.

(Fifth Embodiment) Next, a fifth embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 5, a light receiving unit 50 that receives a signal from the remote controller 49 for setting adjustment, a microcomputer 51 that processes the remote controller signal into a control signal that controls the waveform generation circuit 53, and a memory 52 that records the control signal. By inputting the H pulse synchronized with the horizontal synchronization signal, the V pulse synchronized with the vertical synchronization signal, and the control signal from the outside,
Arbitrary waveform and adjustment mode for 3 fields of blue and green
Waveform generation circuit 53 for generating an on-screen signal for clearly indicating the color, a modulation circuit 54 for respectively modulating the primary color signal with an arbitrary waveform generated by the waveform generation circuit 53, and an on-screen signal generated by the waveform generation circuit 53. Is incorporated in the primary color signal by a switching circuit 55.

The operation of this embodiment configured as described above will be described with reference to FIGS. 5 (a) and 5 (b). Microcomputer 51
The processing mode is a brightness correction mode in which the control signal generated by the microcomputer 51 is changed in the same manner simultaneously by the operation of the remote controller 49 to generate the waveforms generated by the waveform generation circuit 53 in the red, blue and green directions. It is set to a color temperature correction mode in which the generated waveform of the circuit 53 is changed for red, blue and green separately. For example,
When the all-white signal is received during set adjustment of the three-tube rear-projection television, and there is a point 57 on the screen 56 where the brightness is lower than the center of the screen, the remote controller 49
Operation, the processing mode of the microcomputer 51 is set to the brightness correction, the adjustment point displayed by the on-screen is aligned with the point 57, and the modulation circuit 54 is adjusted so that the red, blue and green drive amounts become high. Adjust the modulation waveform input to.

Further, when there is a point 58 on the screen 56 where the color temperature is lower than the center of the screen, the processing mode of the microcomputer 51 is set to the color temperature correction by operating the remote controller 49 and the on-screen display is performed. The adjustment point is adjusted to the point 58, the modulation waveform input to the modulation circuit 54 is adjusted so that the color temperature approaches the center of the screen, and the red / blue drive amount is adjusted.

The control signal set in this way is stored in the memory 52, and even if the control signal is output from the waveform generating circuit 53.
The waveform set to is continuously generated. By repeating these operations, it is possible to simultaneously improve the brightness of the entire screen and the uniformity of white. In addition, after installation on the market, it is possible to make adjustments using the remote control without an adjustment jig.

[0034]

According to the present invention, it is possible to improve the non-uniformity of white on the left and right of the screen and the decrease in the brightness around the screen which occur in the three-tube rear integrated projection television. Further, in the liquid crystal system, it is possible to improve irregular white nonuniformity due to unevenness of transmittance in the liquid crystal panel and reduction in luminance around the screen.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a second embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a third embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a fourth embodiment of the present invention.

FIG. 5 is an explanatory diagram showing a fifth embodiment of the present invention.

[Explanation of symbols]

1, 2, 3, 4, 5, 6, 7 Color temperature sensor 8 CPU 9 Microcomputer 10 Memory 11 Waveform generation circuit 12 Modulation circuit 13, 14, 15, 16, 17, 18, 19 Brightness sensor 20 CPU 21 Microcomputer 22 Memory 23 waveform generation circuit 24 modulation circuit 25, 26, 27, 28, 29, 30, 31 color temperature sensor 32 CPU 33 microcomputer 34 memory 35 waveform generation circuit 36 modulation circuit 37, 38, 39, 40, 41, 42, 43 luminance Dual color temperature sensor 44 CPU 45 Microcomputer 46 Memory 47 Waveform generation circuit 48 Modulation circuit 49 Remote control 50 Light receiving section 51 Microcomputer 52 Memory 53 Waveform generation circuit 54 Modulation circuit 55 Switching circuit 56 Screen 57, 58 Adjustment points

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H04N 9/73 H04N 9/73 Z

Claims (5)

[Claims] 1. A plurality of color temperature sensors for detecting white balance, an external CPU for controlling the detected values from the color temperature sensors to be arbitrary values, and an H pulse synchronized with a horizontal / vertical synchronizing signal. And a V pulse and a control signal from the external CPU to generate two kinds of arbitrary waveforms for one field, a memory for storing the control signal, and red and blue primary color signals in the signal generation circuit. A shading correction circuit including a modulation circuit that modulates each generated arbitrary waveform. 2. A plurality of brightness sensors for detecting brightness,
An external CPU that controls the detected value from the brightness sensor to be an arbitrary value, an H pulse and a V pulse that are synchronized with a horizontal / vertical synchronization signal, and a control signal from the external CPU for an arbitrary one field. A signal generating circuit for generating one kind of waveform, a memory for storing the control signal,
A shading correction circuit comprising a modulation circuit that modulates a luminance signal with an arbitrary waveform generated by the signal generation circuit. 3. A plurality of brightness sensors for detecting brightness,
An external CPU that controls the detected value from the brightness sensor to be an arbitrary value, an H pulse and a V pulse that are synchronized with a horizontal / vertical synchronization signal, and a control signal from the external CPU for an arbitrary one field. A signal generating circuit for generating three types of waveforms, a memory for storing the control signal,
A shading correction circuit comprising a modulation circuit that modulates red, blue, and green primary color signals with arbitrary waveforms generated by the signal generation circuit. 4. A plurality of sensors for detecting brightness and color temperature, an external CPU for controlling the detection values from the sensors to be arbitrary values, and an H pulse and V synchronized with horizontal / vertical synchronization signals. A signal generating circuit for generating three kinds of arbitrary waveforms for one field by a pulse and a control signal from the external CPU, a memory for storing the control signal, and red, blue, and green primary color signals are generated by the signal generating circuit. A shading correction circuit that includes a modulation circuit that modulates each with an arbitrary waveform. 5. A microcomputer for receiving a remote control signal and processing a control signal for controlling a waveform generating circuit, which will be described later, a memory for storing the control signal, and H and V pulses synchronized with horizontal and vertical synchronizing signals. With the control signal, a waveform generating circuit for generating an on-screen signal for clearly indicating an arbitrary waveform for three fields of red, blue, and green and an adjustment mode, and an arbitrary waveform generated by the waveform generating circuit. Shading correction circuit comprising a modulation circuit for respectively modulating the primary color signals with the waveform of 1. and a switching circuit for incorporating the on-screen signal generated by the waveform generation circuit into the primary color signals.