JPH08248914A - Drive circuit of field emission element - Google Patents

Abstract

PURPOSE: To improve a luminance characteristic so as to improve a luminance characteristic of a pixel which can provide a high quality image. CONSTITUTION: A driving circuit for an electric field discharge element is provided with detecting means 35, 39 detecting an electric current change in each pixel in a screen display unit, an A/D converter 41 which is connected to output terminals of the detecting means 35, 39 and converts output signals into digital signals, a memory element 45 in which information serving as a reference of a luminance characteristic to each pixel is stored, a subtracter 45 to which a signal outputted from the A/D converter 41 and a signal provided from the memory element 45 are inputted so as to be subtracted, a luminance processing unit 47 which obtains respective luminance characteristics from the signals from the subtracter 43 so as to store them, and an udder 25 adding a digitized video signal and the signal outputted from the luminance processing unit 47 together.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a field emission device (FED;
Field Eission Display) drive circuit, more specifically, to a field emission device drive circuit provided so that each pixel of the screen display unit has a constant luminance characteristic.

[0002]

2. Description of the Related Art Generally, flat panel display devices adopt a matrix type driving system due to their structural characteristics. In order to implement a gray scale, an amplitude modulation system and a pulse width modulation system are roughly classified. I am using. Both the amplitude modulation method and the pulse width modulation method are applied to the field emission device (FE).
D) can be used. However, since the pulse width modulation method has a limitation in realizing the gray scale, the amplitude modulation method is mainly used for the field emission device.

[0003]

Problems to be Solved by the Invention FIGS. 3 (A) and 3
(B) is a circuit diagram showing a conventional drive circuit for a field emission device. FIG. 3A is a drive circuit diagram of a field emission device using an amplitude modulation method, and FIG. 3B is a drive circuit diagram of a field emission device using a pulse width modulation method.

First, referring to FIG. 3A, in order to display an input video signal, an amplifier 103 for amplifying the video signal and the video signal amplified by the amplifier 103, information is displayed according to a sampling rate. Each pixel of the screen display unit 107, which is a field emission device (FED), is illuminated through a sample holder 105 that is sampled and stored to provide an image. Of course, a bias power source 109 that causes field emission is grounded in series in this circuit. In this way, the drive circuit of the field emission device using the amplitude modulation method is
The circuit structure of the FED capable of driving an existing drive voltage of 40 V or more is complicated, and there is a disadvantage that there is no standard integrated circuit.

Further, the characteristics of each pixel may be different due to a minute environmental change in the process, and a defective pixel may occur, but a compensating circuit corresponding thereto is not provided.

Next, referring to FIG. 3B, the input video signal is converted into a digital signal through the A / D converter 113, and this digital signal is converted into the pulse width modulator 1.
Each pixel of the screen display unit 117 including a field emission device (FED) is illuminated through 15 to provide an image. The pulse width modulation method is limited in the realization of a gray scale, and similar to the field emission device using the amplitude modulation method, a scale may be displayed in an image display due to a minute difference in pixel and a unique characteristic of each pixel. However, the defective pixel is not corrected and the defective pixel is not corrected. Therefore, there is a problem that the life is shortened.

The present invention has been made in view of such conventional problems, and an object thereof is to feed back information regarding the characteristics of each pixel forming a screen display portion for the purpose of extending the life. Another object of the present invention is to provide a driving circuit of a field emission device which irradiates each pixel with a video signal by adding and correcting the video signal.

[0008]

In order to achieve the above object, a first invention according to claim 1 is a detecting means for detecting a current change of each pixel of the screen display section, and a detecting means of the detecting means. An A / D converter coupled to the output terminal for converting the output signal into a digital signal, a memory element in which information as a reference of the luminance characteristic for each pixel is stored, and the A / D converter outputs the information. A subtractor for receiving and subtracting a signal and a signal provided from the memory element, a luminance processing section for obtaining and storing respective luminance characteristics from the signal provided by the subtractor, and a digitized video signal The gist of the present invention is to include an adder that adds the signal output from the brightness processing unit.

A second aspect of the present invention is provided by the luminance processing section so that the type of signal input from the luminance processing section and the type of the video signal are the same type of signal. The gist is that a D / A converter for converting the signal to be converted into an analog signal is further provided between the adder and the luminance processing unit.

According to a third aspect of the present invention, the video signal is converted into a digital signal so that the type of the signal input from the luminance processing section and the type of the video signal are the same type of signal. An A / D converter is provided at a video signal input terminal of the adder, and a D / A converter for converting a digital signal provided from the adder into an analog signal is further provided between the adder and the amplifier. The point is to be prepared.

According to a fourth aspect of the present invention, the detection means detects a resistance element provided between each of the pixels and the bias power source and a voltage difference between both ends of the resistance element. The gist of the present invention is that it comprises a differential amplifier that amplifies.

[0012]

With the above arrangement, in the drive circuit for the field emission device according to the first aspect of the present invention, the detecting means detects the current change of each pixel of the screen display section,
The / D converter is coupled to the output terminal of the detecting means and converts the output signal into a digital signal. After conversion, the subtractor
The signal output from the A / D converter and the signal provided from the memory device in which the information serving as the reference of the luminance characteristic for each pixel is stored are input and subtracted. After the subtraction, the video signal digitized by the adder and the signal output from the brightness processing unit which obtains and stores the respective brightness characteristics from the signal provided from the subtractor are added. By improving the brightness characteristics by correcting the input video signal by feeding back the information regarding the characteristics of each pixel forming the screen display section,
High quality images can be provided.

According to a second aspect of the present invention, the signal provided from the brightness processing unit is an analog signal so that the type of the signal input from the brightness processing unit and the type of the video signal are the same type of signal. Since a D / A converter for converting to A is further provided between the adder and the luminance processing unit,
The number of parts can be reduced without using the / D converter.

A third aspect of the present invention is an A / D converter for converting a video signal into a digital signal so that the type of the signal input from the luminance processing section and the type of the video signal are the same type. Is provided at a video signal input terminal of the adder, and a D / A converter for converting a digital signal provided from the adder into an analog signal is further provided between the adder and the amplifier. The voltage between both ends is differentially amplified, and the current change amount of each pixel can be detected by the voltage difference between both ends.

In a fourth aspect of the present invention, the detection means includes a resistance element provided between each of the pixels and the bias power source, and a differential amplifier for detecting and amplifying a voltage difference between both ends of the resistance element. Therefore, the form of the signal input to the adder and the form of the signal provided from the brightness processing unit can be matched.

[0016]

Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings.

In the present invention, a video signal is applied to each pixel of the screen display unit by utilizing the amplitude modulation method.

Referring to FIG. 1, an amplifier 29 for amplifying a provided video signal, a sample holder (S / H) 31 for instantaneously capturing and storing the amplified video signal and a screen display unit 33 are provided. The screen display unit 33 is provided in sequence.
A bias power supply 37 that provides field emission is provided in series between the ground and the ground.

In the circuit diagram thus constructed, a feedback loop is further provided between the bias power source 37 and the amplifier 29 in order to improve the characteristics of the pixel.

The feedback loop is a loop for detecting the amount of change in the current flowing in each pixel of the screen display unit 29 and correcting the luminance characteristic of each pixel. Therefore, the resistance element 35 is provided between the screen display unit 33 and the bias power supply 37. The current change amount of each pixel is detected by the voltage difference across the resistance element 35.

That is, the feedback loop is a differential amplifier 3 which differentially amplifies the voltage across the resistance element 35.
9, an A / D converter 41 that converts the signal amplified by the differential amplifier 39 into a digital signal, a ROM 45 that is a memory element that stores data relating to the reference luminance of the pixel, A subtractor 43 that subtracts the signal output from the A / D converter 41 and the signal provided from the memory element 45, and obtains and stores each luminance characteristic from the signal detected by the subtractor 43. The brightness processing unit 47. In addition, the feedback loop includes an adder 25 at an input terminal of an amplifier 29 provided with a video signal.
It has. The adder 25 adds the video signal and the signal provided from the luminance processing unit 47 and transmits the added video signal to the amplifier 29.

In this case, the signal provided from the brightness processing unit 47 is a digital signal, and the signal provided from the video signal is an analog signal. The adder 25
It is necessary to match the form of the signal input to the above with the form of the signal provided from the luminance processing unit 47. Therefore, the A / D converter 23 for converting the video signal input to the input terminal of the adder 25 into a digital signal is provided, and the adder 25 converts the signal input into the amplifier 29 into an analog signal. A D / A converter 27 is further provided between the amplifier and the amplifier 29.

The resistance element 35 and the differential amplifier 39 are
It may be replaced with all the sensing means for sensing the brightness change of each pixel of the screen display unit 33, and is not necessarily limited to being arranged in series between the screen display unit 33 and the bias power supply 37. Absent.

FIG. 2 is a circuit diagram showing another embodiment of the drive circuit of the field emission device according to the present invention.

The configuration of the circuit is the same as that of FIG. 1 except that the installation position of a converter for mutually converting an analog signal and a digital signal is different. In order to match the video signal and the signal transmitted from the brightness processing unit 47 to the same type, D / is provided between the adder 25 and the brightness processing unit 47.
An A converter 49 was provided.

As described above, since the D / A converter 49 is provided between the adder 25 and the brightness processing section 47,
The number of parts can be reduced without using the D converter.

[0027]

As described above, in the drive circuit for the field emission device according to the first aspect of the present invention, the detection means detects the current change of each pixel of the screen display unit, and the A / D conversion is performed. Is connected to the output terminal of the detecting means by a detector and the output signal is converted into a digital signal. After the conversion, the subtractor inputs and subtracts the signal output from the A / D converter and the signal provided from the memory element in which the information serving as the reference of the luminance characteristic for each pixel is stored. After the subtraction, the video signal digitized by the adder and the signal output from the brightness processing unit which obtains and stores the respective brightness characteristics from the signal provided from the subtractor are added. By feeding back information regarding the characteristics of each pixel forming the screen display section and correcting the input video signal, it is possible to improve the luminance characteristic and provide a high quality image.

In a second aspect, the signal provided from the brightness processing section is an analog signal so that the type of the signal input from the brightness processing section and the type of the video signal are the same type of signal. Since a D / A converter for converting to A is further provided between the adder and the luminance processing unit,
The number of parts can be reduced without using the / D converter.

A third aspect of the present invention is an A / D converter for converting a video signal into a digital signal so that the type of the signal input from the luminance processing section and the type of the video signal are the same type. Is provided at a video signal input terminal of the adder, and a D / A converter for converting a digital signal provided from the adder into an analog signal is further provided between the adder and the amplifier. The voltage between both ends is differentially amplified, and the current change amount of each pixel can be detected by the voltage difference between both ends.

In a fourth aspect of the present invention, the detection means includes a resistance element provided between each of the pixels and the bias power source, and a differential amplifier for detecting and amplifying a voltage difference between both ends of the resistance element. Therefore, the form of the signal input to the adder and the form of the signal provided from the brightness processing unit can be matched.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a drive circuit for a field emission device according to the present invention.

FIG. 2 is a circuit diagram showing another embodiment of the drive circuit of the field emission device according to the present invention.

FIG. 3 is a circuit diagram showing a drive circuit of a conventional field emission device.

[Explanation of symbols]

 23 A / D converter 25 Adder 27 D / A converter 29 Amplifier 31 Sample holder 33 Screen display section 35 Resistor element 37 Bias power supply 39 Differential amplifier 41 A / D converter 43 Subtractor 45 Memory element 47 Luminance Processing unit

Claims (4)

[Claims] 1. An amplifier for amplifying an input video signal, a sample holder for instantaneously capturing and storing the amplified video signal, and a plurality of display units for displaying the signal captured by the sample holder. In a drive circuit of a field emission device that sequentially provides a screen display unit composed of pixels and a bias power supply that causes field emission to each pixel of the screen display unit, a current change of each pixel of the screen display unit is provided. A detection unit for detecting the above, an A / D converter coupled to the output end of the detection unit for converting the output signal into a digital signal, and a memory element storing information serving as a reference of the luminance characteristic for each pixel. , A subtractor for receiving and subtracting the signal output from the A / D converter and the signal provided from the memory element, and a subtracter for each of the signals provided from the subtractor Luminance processing section and the drive circuit of the field emission device characterized by comprising an adder for adding the signal output as digitized video signal from the luminance processing unit for storing obtaining luminance characteristics of. 2. The signal provided from the brightness processing unit is converted into an analog signal so that the type of the signal input from the brightness processing unit and the type of the video signal are the same type of signal. The driving circuit of the field emission device according to claim 1, further comprising an A / A converter between the adder and the brightness processing unit. 3. An A / D for converting a video signal into a digital signal so that the type of the signal input from the luminance processing unit and the type of the video signal are the same type.
A converter is provided at a video signal input terminal of the adder, and a D / A converter for converting a digital signal provided from the adder into an analog signal is further provided between the adder and the amplifier. The drive circuit for a field emission device according to claim 1, wherein: 4. The detection means includes a resistance element provided between each of the pixels and the bias power supply, and a differential amplifier that detects and amplifies a voltage difference between both ends of the resistance element. The drive circuit for a field emission device according to claim 1, wherein: