JPH1115431A - Electric field emission display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an FED(field emission display) device compensating an effect of anode source voltage fluctuation for luminance without using a highly stabilized power source for an anode power source circuit. SOLUTION: This device is provided with the FED main body 1 provided with a display substrate arranged with plural pixels Pij having an electric field emission emitter driven by a gate electrode in matrix, formed with gate wiring commonly driving the pixels in the row direction and emitter wiring commonly driving emitters in the column direction, and a counter substrate arranged oppositely on this display substrate and formed with an anode electrode and a fluorescent body film, and a voltage detection circuit 7 having the anode power source circuit 2, a gate drive circuit 3 and an emitter drive circuit 4 and monitoring the anode source voltage fluctuation outputted from the anode power source circuit 2. At this time, the gate power source circuit 6 is variable controlled so that its source voltage causes the fluctuation of the polarity opposite to the anode source voltage fluctuation according to the output of the voltage detection circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field emission display device using a display substrate formed by arranging minute field emission type emitters.

[0002]

2. Description of the Related Art In recent years, as a flat panel display, a field emission display (FED) using a small emitter as an electron source has been developed.
Emission Display) is attracting attention. The FED is composed of a display substrate on which a plurality of pixels having a field emission type emitter driven by a gate electrode are formed and arranged, and an opposite substrate on which an anode electrode and a phosphor film are formed facing the display substrate. You. The space between the display substrate and the counter substrate is evacuated. A plurality of gate lines that commonly drive the pixels in the row direction on the display substrate and a plurality of emitter lines that commonly drive the field emission emitters of the pixels in the column direction are taken out. Then, for example, while sequentially driving the gate wiring, synchronously, by applying image data for each line to the emitter wiring, a so-called line-sequential driving image display is performed.

For example, by sequentially applying a positive gate voltage pulse (for example, +25 V) to the gate wiring,
Selection is performed line by line, and in synchronization with this, a negative emitter voltage pulse (for example, −25 V) is applied to each emitter wiring according to image data. +2 for gate wiring
In a pixel to which 5 V is applied and -25 V is applied to the emitter wiring, the voltage between the gate and the emitter becomes 50 V to emit electrons, and the electrons are emitted by a positive high voltage of 500 V to 6 kV.
Is accelerated toward the anode electrode side to which light is applied, and emits light by hitting the phosphor film. The gradation display of the FED can be realized by controlling the pulse width of the above-mentioned emitter voltage pulse as a PWM (pulse width modulation) pulse.

As the anode power supply circuit of the FED, for example, a DC power supply circuit of a switching inverter type is used.
The display performance of the ED is adversely affected. That is, the emission current of each pixel of the FED is accelerated by the anode power supply voltage, hits the phosphor film on the anode electrode, and the anode current flows in the range of 0 to 1 mA according to an image to be displayed. However, if the anode power supply voltage drops due to the flow of the anode current, the required brightness cannot be obtained.
Therefore, as the anode power supply circuit, a highly stabilized power supply that can obtain a constant stabilized output voltage regardless of a load change (that is, an anode current change) is desired.

[0005]

However, since the anode power supply circuit of the FED has a high voltage of 500 V to 6 kV as described above, it has a high stability by incorporating a feedback circuit for feeding back its secondary output to the primary side. When an integrated power supply circuit is configured, individual components having a high withstand voltage must be used for the resistance and the capacitor of the feedback circuit, and thus there is a problem that the anode power supply circuit becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an FED device capable of compensating for the influence of a change in anode power supply voltage on luminance without using a highly stabilized power supply in an anode power supply circuit.

[0007]

According to the present invention, there is provided an FED device in which a plurality of pixels having a field emission type emitter driven by a gate electrode are arranged in a matrix, and a plurality of gate wirings for commonly driving pixels in a row direction. And a display substrate on which a plurality of emitter wirings for commonly driving field emission emitters in the column direction are formed, and a counter substrate disposed opposite to the display substrate and having an anode electrode and a phosphor film formed thereon.
A device main body, an anode power supply circuit for applying an anode power supply voltage to the anode electrode, a gate drive circuit for selectively driving the plurality of gate lines, and an emitter drive circuit for selectively driving the plurality of emitter lines A voltage detecting means for monitoring a change in an anode power supply voltage output from the anode power supply circuit, and a gate power supply voltage supplied to the gate drive circuit, and the gate power supply voltage is changed according to the output of the voltage detecting means. A gate power supply circuit variably controlled so as to generate a change in polarity opposite to the change in the anode power supply voltage.

In the present invention, a variable voltage source whose output voltage is variably controlled is used as a gate power supply circuit for applying a gate power supply voltage to the gate drive circuit, and while monitoring the anode power supply fluctuation, A change in the polarity opposite to that described above is applied to the gate power supply voltage. Therefore, according to the present invention, when the anode power supply voltage fluctuates according to the load current, the emission characteristic by controlling the gate power supply voltage is controlled in accordance with the fluctuation, whereby the brightness of the FED due to the fluctuation of the anode power supply voltage is reduced. So that the effects are offset. According to the present invention, it is not necessary to use a highly stabilized power supply having a built-in feedback circuit as the anode power supply circuit, and the power supply circuit of the FED can be reduced in size, ASIC, and cost can be reduced.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an overall configuration of an FED device according to an embodiment, FIG. 2 shows a layout of four pixels on the display substrate 10 side of the FED main body 1, and FIG.
2 shows a cross-sectional structure of the FED main body 1 at a position -A '.

As shown in FIG. 3, the FED main body 1 includes a display substrate 10 and an opposing substrate 20 disposed opposite to the display substrate. The display substrate 10 is configured using, for example, a silicon substrate 11 and includes a plurality of pixels Pij (i
= 1 to m, j = 1 to n) are arranged in a matrix. Display substrate 1
Field emission type emitter (hereinafter simply referred to as an emitter) 12 having a sharp tip at a position corresponding to each pixel Pij of 0
Are formed, for example, four by four. FIG. 3 shows only one emitter 12 for each pixel for convenience. When performing full-color image display, each pixel is composed of R, G, and B dots, and an emitter 12 is formed in each dot region.

The emitter wirings 13 for commonly driving the emitters 12 in the column direction are separated from each other by an insulating film 16.
One pixel is provided for each pixel (in the case of full color, three R, G, and B pixels are provided for each pixel), and are externally extracted as emitter terminals E (E1, E2,...). Gate wiring (electrode) 1 for commonly driving each emitter 12 in the row direction
4 is formed on a substrate 11 via an insulating film 17, and a hole 15 from which each emitter 12 is exposed is processed. Each gate line 14 has a gate terminal G (G1, G2,
…).

The opposite substrate 20 is made of a transparent substrate 21 such as glass.
The anode electrode 22 made of a transparent conductive film such as ITO is formed on the surface thereof, and the phosphor film 23 is formed on the anode electrode 22 corresponding to each pixel. The anode electrode 22 is taken out as an anode terminal A to the outside. Although not shown, the space between the display substrate 10 and the counter substrate 20 is vacuum-sealed with a sealing material such as low-melting glass. In this case, preferably, a getter material such as a barium alloy or a zirconium alloy is sealed inside the FED main body 1.

As shown in FIG. 1, as a driving circuit of the FED main body 1 configured as described above, a gate driving circuit 3 for sequentially supplying a gate voltage pulse to a gate terminal G, and in synchronization with the gate driving circuit 3, An emitter drive circuit 4 for supplying an emitter voltage pulse corresponding to image data to the emitter terminal E is provided. The controller 5 controls the synchronization of the gate drive circuit 3 and the emitter drive circuit 4. Normally, in the case of performing line-sequential image display, image data of one line is sequentially sent to the emitter driving circuit 4, and image data constituting one line are simultaneously supplied to the n emitter terminals E, and gate driving is performed. One gate terminal G is selectively driven by the circuit 3 to display an image of one line. Thereafter, the gate terminal G is selectively driven sequentially for one line of image data.

The anode power supply circuit 2 applies a positive DC high voltage of about several hundred volts to several kV to the anode terminal A, and the gate power supply circuit 6 supplies several tens of volts of positive DC power to the gate drive circuit 3. This is to give a voltage. In this embodiment, the gate power supply circuit 6 is a variable voltage source, and is provided with a voltage fluctuation detection circuit 7 for detecting a fluctuation in the output voltage of the anode power supply circuit 2. The output voltage of the power supply circuit 6 is variably controlled.

FIG. 4 shows a specific configuration of the above-described anode power supply circuit 2, voltage fluctuation detection circuit 7, and gate power supply circuit 6. The anode power supply circuit 2 includes a switching inverter 41, a transformer 42 connected to the switching inverter 41, and a rectifying / smoothing circuit 43 provided on a secondary side thereof. No feedback circuit is provided for output stabilization. The voltage fluctuation detection circuit 7 includes resistors R1 and R
2 is a resistance voltage dividing circuit in which 2 are connected in series. For example, R1 =
Assuming that 6 GΩ and R2 = 6 MΩ, a change in anode power supply voltage can be detected by a very small current of about 1 μA.

The gate power supply circuit 6 includes the anode power supply circuit 2
And a rectifying / smoothing circuit 44 for rectifying and smoothing the intermediate tap output of the transformer secondary side, and the output voltage value being variably controlled by the output obtained from the voltage fluctuation detecting circuit 7 based on the rectified / smoothed output. And a log amplifier 46 for logarithmically converting the output. The variable voltage source 45 is designed such that its output voltage shows a change in the polarity opposite to the polarity of the output voltage change of the anode power supply circuit 2 (therefore, the change polarity of the output voltage of the voltage change detection circuit 7).

Although a specific relationship between the fluctuation of the voltage applied to the anode terminal A due to the load fluctuation and the fluctuation of the voltage applied to the gate terminal G by a pulse is not shown, the anode terminal A
The variable gain of the variable voltage source 45 is designed such that a change in the luminance of the FED caused by the voltage change of the FED is just offset by a change in the emission characteristic due to a change in the voltage applied to the gate terminal G. On the other hand, while the change due to the load change of the voltage applied to the anode terminal A and the luminance change have a linear relationship, the relationship between the change in the voltage applied to the gate terminal G and the emission current is represented by an exponential function. Therefore, by passing the output of the variable voltage source 45 through the log amplifier 46, the linear relationship between the fluctuation of the voltage applied to the gate terminal G and the emission current is maintained.

As described above, according to this embodiment, it is possible to compensate for the influence of the anode voltage fluctuation caused by the load fluctuation on the luminance by adjusting the gate voltage without using a highly stabilized power supply for the anode power supply circuit 2. it can. That is, when the anode voltage is reduced by the load current and the luminance is to be lowered, the gate drive voltage is increased and the emission current is increased, thereby compensating for the luminance reduction. According to this embodiment, it is not necessary to provide a feedback circuit for stabilizing the output in the anode power supply circuit 2 handling a high voltage, so that it is easy to reduce the size of the power supply circuit, to implement an ASIC, and to reduce the FED. Cost reduction is achieved.

[0019]

As described above, according to the present invention, it is possible to compensate for the influence of the load current on the luminance of the anode power supply voltage fluctuation without using a highly stabilized power supply with a built-in feedback circuit as the anode power supply circuit. Thus, an FED with reduced size and reduced cost can be obtained.

[Brief description of the drawings]

FIG. 1 shows a configuration of an FED device according to an embodiment of the present invention.

FIG. 2 shows a layout of a main part on the display substrate side of the FED main body of the embodiment.

FIG. 3 shows a sectional structure of a main part of the FED body of the embodiment.

FIG. 4 shows a configuration of an anode and gate power supply circuit section of the embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... FED main body, 2 ... Anode power circuit, 3 ... Gate drive circuit, 4 ... Emitter drive circuit, 5 ... Controller, 6
... gate power supply circuit, 7 ... voltage fluctuation detection circuit, Pij ... pixel, G ... gate terminal, E ... emitter terminal.

Claims (1)

[Claims] A plurality of pixels having a field emission type emitter driven by a gate electrode are arranged in a matrix, and a plurality of gate lines for commonly driving pixels in a row direction and a field emission type emitter for a column direction are commonly driven. A display device main body having a display substrate on which a plurality of emitter wirings are formed, an opposing substrate disposed opposite to the display substrate and having an anode electrode and a phosphor film formed thereon, and applying an anode power supply voltage to the anode electrode An anode power supply circuit; a gate drive circuit for selectively driving the plurality of gate wirings; an emitter drive circuit for selectively driving the plurality of emitter wirings; and an anode power supply voltage output from the anode power supply circuit. Voltage detection means for monitoring the fluctuation of the gate power supply, and supplying a gate power supply voltage to the gate drive circuit; Field emission display device characterized by comprising a gate power supply circuit is variably controlled to produce a variation of the change and opposite polarity of the anode power supply voltage according to the output of said voltage detecting means.