KR19990028056A - Multi-gate driver for field emission indicator - Google Patents

Abstract

SUMMARY OF THE INVENTION The present invention provides a multi-gate driving device of a field emission indicator which can realize a better gray scale by dividing a plurality of gates and time-divisionally driving each multi-gate during one scan signal.

To this end, the present invention, the shift register for sequentially outputting the data input from the outside in synchronization with the clock signal, the latch for temporarily storing and outputting the data output from the shift register, and the data output from the latch for a predetermined period And a multiplexer that receives the signal from the AND gate and determines a gate to be scanned according to a selection signal, and the gate is divided into a plurality of sub-gates, so that the gate is divided into a plurality of sub-gates. Accurate gray scale implementation and better multilevel gradation processing can be performed.

Description

Multi-gate driver for field emission indicator

The present invention relates to a multi-gate driving device of a field emission indicator, and more particularly, to a multi-gate driving device of a field emission indicator in which each gate is divided into a predetermined number.

An example of a device that has recently been in the spotlight as a flat panel display is a liquid crystal display, which uses an liquid crystal to intercept this light beam from a light source so that an image is displayed. There is a designation method and an active matrix specification method.

The manual matrix designation method is a method of inputting data to pixels at intersections by applying different voltages to the upper and lower plates of the glass substrate in the liquid crystal display. According to this method, the peripheral pixels of the designated pixel are also affected. Since it requires a compensation circuit for realizing a clear screen, the driving circuit portion is complicated.

In addition, the active matrix designation method includes one cell transistor and one capacitance per pixel such that one pixel is continuously driven after the previous pixel data until the next pixel data is input, thereby improving image quality. It can be said that the method which simplifies and a drive circuit part was sought.

However, according to the active matrix designation method, it is possible to improve the image quality and simplify the driving circuit. However, since a large number of transistors and capacitances have to be planted on the glass substrate of the liquid crystal display, the process is very complicated and the yield is also low. have.

These liquid crystal displays currently occupy the largest flat panel display market, and since only a few percent of the light source actually contributes to the screen, it requires a lot of power consumption, has difficulty in making a large area, and a semi-liquid material (liquid crystal). ), It is sensitive to changes in ambient temperature, it is also weak in pressure, not bright on the screen, and has a limited resolution, so there are many limitations in the application.

As a new flat panel indicator to overcome this problem, a field emission display is proposed. The field emission indicator displays the screen in a similar way to the cathode ray tube (CRT), which displays the screen using the emitted electrons.The field emission indicator displays the thermal electron emission in terms of the use of cold electron emission. It is different from the cathode ray tube (CRT) used.

In the field emission display, field emission elements emitting electrons are provided for each pixel, and electrons from the field emission elements collide with the electrode coated with a fluorescent film so that an image is displayed. Recently, the field emission indicator has solved various problems such as power consumption problems of the liquid crystal display, problems of large area, sensitivity to changes in ambient temperature, weakness of pressure, lack of screen brightness, and limitation of resolution. It is getting the spotlight as the next generation flat panel indicator that can give.

The field emission indicator may integrate hundreds to thousands of field emission devices according to a process to form one pixel. The field emission device constituting the pixel of the field emission indicator may include a cathode electrode as shown in FIG. 1. A cathode (12) connected to (10), a gate electrode (14) provided at regular intervals above the cathode (12), and an anode plate (18) on which a fluorescent film (16) is applied on the back side. It is provided.

In this case, the fluorescent film 16 displays an image that generates light corresponding to the amount of electrons colliding with the fluorescent film 16.

In addition, the positive electrode plate 18 plays a role of attracting electrons emitted from the cathode 12, and also has transparency to transmit light by the fluorescent film 16.

In addition, the cathode 12 has the shape of a horn forming the upper part of the tent and allows electrons to be emitted from its own tent by a driving power source from the cathode electrode 10.

In addition, the gate electrode 14 induces electron emission from the cathode 12 to a vacuum state by a high voltage lower than the voltage applied to the positive electrode plate 18, and the emitted electrons are subjected to a higher voltage. Toward the positive electrode plate 18.

As a driving method of a conventional field emission indicator equipped with such a field emission device, a high voltage scan signal is applied to a gate electrode, a low voltage data signal is applied to an emitter terminal, and a pulse size of the data signal is modulated. The gray scale is realized by controlling the amount of current flowing through the emitter tip.

However, in such a conventional field emission indicator, when the electrons are emitted from the cathode, they are not emitted from the 100% cathode but are somehow lost to the gate, so that an accurate gray scale cannot be realized.

Accordingly, the present invention has been made in view of the above circumstances, and the multi-gate driving apparatus of the field emission indicator which can realize better gray scale by dividing the gate into plural gates and time-divisionally driving each multi-gate during one scan signal is provided. The purpose is to provide.

According to a preferred embodiment of the present invention to achieve the above object, a shift register for sequentially outputting the data input from the outside in synchronization with the clock signal, a latch for temporarily storing and outputting the data output from the shift register; And a multiplexer configured to hold a data output from the latch for a predetermined period of time, and a multiplexer configured to receive a signal from the AND gate and determine a gate to be scanned according to a selection signal. A multi-gate driver for a field emission indicator is provided.

1 is a view for explaining the structure of a conventional field emission device;

2 is a diagram showing the configuration of a multi-gate driving device of a field emission indicator according to an embodiment of the present invention;

3 is a time division scan waveform diagram employed in describing an embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

10: cathode electrode, 12: cathode, 14: gate electrode, 16: fluorescent film, 18: bipolar plate, 20: shift register, 22: latch, 24: end gate, 26: multiplexer, 27-30: subgate, 31 ~ 34: cathode

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a diagram illustrating a configuration of a multi-gate driving device of a field emission indicator according to an exemplary embodiment of the present invention. The shift register 20 sequentially synchronizes externally input data with a clock signal CLK. The latch 22 temporarily stores data sequentially applied from the shift register 20 and temporarily stores the data when the operation is enabled by the enable signal ENA 1 from a controller (not shown). Data is outputted, and the AND gate 24 maintains the data applied from the latch 22 for a predetermined time and when the operation is enabled by the enable signal ENA 2 from a controller (not shown). Outputs

The multiplexer 26 receives the signal output from the AND gate 24 and receives a predetermined number (four in the embodiment of the present invention) by the selection signal SEL from a controller (not shown). , 28, 29 and 30 are time-divisionally driven.

The multiplexer 926 in the figure includes two multiplexers on each output line of the AND gate 24.

That is, two multiplexers 26a and 26b are connected in parallel to the first output line of the AND gate 24, and a selection preference SEL is applied to each of the multiplexers 26a and 26b, and each multiplexer ( 26a and 26b selectively drive the two sub gates 27, 29: 28 and 30.

As described above, multiplexers having the same configuration are also connected to other output lines of the AND gate 24.

Next, the operation of the multi-gate driving device of the field emission indicator according to the embodiment of the present invention configured as described above is as follows.

Data sequentially output from the shift register 20 is temporarily stored in the latch 22 and then applied to the AND gate 24, and the AND gate 24 enables the enable signal ENA 2 from a controller (not shown). Is input, the data input from the latch 22 is applied to the multiplexer 26, and the multiplexer 26 scans the plurality of sub gates 27, 28, 29, and 30 according to the selection signal SEL. do.

In other words, as illustrated in FIG. 3, a plurality of sub-scan signals G1 / 4, G2 / 4, G3 / 4, and G4 / 4 are inputted time-divisionally during one scan signal G1. It becomes a time constant element which modulates the driving pulse inputted to (Q).

In the embodiment of the present invention, four bits (16 grays) of gray scale display are enabled by using four resistors, but the number can be added or subtracted if necessary.

The plurality of switching elements 20, 22, 24, and 26 are analog switches, and data signals D1, D2, D3, and D4 are applied to each of the switching elements, and depending on whether the data signals are applied. The on / off of the analog switch is determined.

That is, for example, when the total resistance up to the connection point between the power supply terminal V _DD and the capacitor C and the inverter IV2 is set to Rx as exemplarily shown in FIG. The resistor Rx becomes as shown in Table 1 below according to the data signal D1, D2, D3, and D4 input states.

TABLE 1

The signal of the AND gate 24 input to the flexor 26 is processed through the multiplexer 26.

For example, a case of one output line of the AND gate 24 will be described. When the selection signal SEL is 0, the two multiplexers 26a and 26b do not operate. When the selection signal SEL is 1, the multiplexers 26a and 26b do not operate. Only the multiplexer 26b is operated. When the selection signal SEL is 10, only the multiplexer 26a is operated. When the selection signal SEL is 11, the two multiplexers 26a and 26b are operated.

When a multiplexer or two multiplexers operate by the selection signal SEL, the multiplexer drives the subgates according to the signal state from the AND gate 24 input to the multiplexers 26a and 26b. Let's go.

For example, when the multiplexer 26a is operated, if the signal of the AND gate 24 input to the multiplexer 26a is 1, the sub gate 27 is driven, and the AND gate 24 is operated. If the signal is 10, the sub gate 29 is driven. If the signal of the AND gate 24 is 11, the two sub gates 27 and 29 are driven. Of course, the same applies to other multiplexers.

When the sub gates 27, 28, 29, 30 are time-divisionally driven as described above, the sub gates 27, 28, 29, 30 are connected between the ground terminals GND according to the resistance values of the resistors R1, R2. Since the amount of current is adjusted, the number of steps of screen gradation processing is increased by the number of divided gates.

According to the present invention as described above, by employing the multiplexer and the multi-divided gate, it is possible to implement a more accurate gray scale implementation and a better multi-level gradation processing as compared with the conventional configuration.

The present invention is not limited only to the above-described embodiments, but may be modified and modified without departing from the scope of the present invention.

Claims (1)

A shift register for sequentially outputting data input from the outside in synchronization with a clock signal; A latch for temporarily storing and outputting data output from the shift register; And gates for maintaining the data output from the latch for a certain period of time, A multiplexer configured to receive a signal from the AND gate and determine a gate to be scanned according to a selection signal, And the gate is divided into a plurality of sub-gates.