Cold cathode discharge display apparatus

Abstract

A cold cathode discharge display apparatus in which a main electrode whose anode consists of a plurality of electrodes while whose cathode is of a plate having a plurality of perforations for discharge space, and a trigger electrode are provided the trigger electrode consisting of a first electrode group for column and a second electrode group for raw, whereby in the display or write operation, a voltage lower than firing voltage but higher than a voltage for sustaining a discharge is applied between the main electrodes and at the same time a drive voltage is applied between the trigger electrodes while in the read-out operation, a voltage lower than firing voltage but higher than the voltage for sustaining the discharge is applied between the trigger electrodes.

Description

BACKGROUND OF THE INVENTION

The present invention relates to a cold cathode discharge display apparatus, and more particularly to a cold cathode discharge display apparatus with memory function.

A cold cathode discharge display apparatus is known in which a plurality of discharge tubes are arranged in dots or specific patterns. In this apparatus, desired patterns displayed by utilizing the discharge occurring between a pair of electrodes which are disposed in inert gas such as argon or neon. In the conventional cold cathode discharge display apparatus a plurality of display units are disposed side by side in the envelope. Each unit consists of a plurality of segment electrodes and a counter electrode disposed to oppose the segment electrodes with a predetermined spacing therebetween. Such a display apparatus is used to display patterns of a plurality of digits by selectively operating the display units on the time division basis at such a high speed that does not cause flickering.

However, because such a display device lacks memory function it is necessary to provide an independent memory device thereby increasing the cost of manufacturing and complicating the construction of the display device.

SUMMARY OF THE INVENTION

Therefore, it is an object of this invention to provide a new and improved cold cathode discharge display apparatus with a memory function without using any expensive external memory device.

Another object of this invention is to provide an improved cold cathode discharge display apparatus capable of compact construction and of manifesting a memory function.

Yet another object of this invention is to provide an improved cold cathode discharge display device which is readily applicable to an associated apparatus such as a computer in reading out the display information thereof.

These and other objects, features and advantages of this invention will become more apparent upon a reading of the following detailed description and the accompanying drawings, in which;

FIG. 1 is a schematic diagram showing the operation of this invention in principle,

FIG. 2 is a perspective view broken away in part showing the electrode structure of a cold cathode discharge display device according to this invention,

FIG. 3 shows a discharge characteristic between the main electrodes, which will aid to understand the operation of this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIG. 1, there is shown a schematic diagram to explain the principle operation of this invention. A main electrode consists of a main cathode electrode a and a main anode electrode b. The main cathode electrode a is connected to one end of a source Ea while the main anode electrode b is connected to one end of a source Eb by way of a resistor R.sub.1. The other ends of the sources Eaand Eb are connected to ground. A trigger electrode consists of a trigger anode electrode X and a trigger cathode electrode Y. The trigger cathode electrode Y is connected to a source terminal Eti and one terminal of a switch S1. The other terminal of the switch S1 is coupled to ground. The trigger anode electrode X is coupled to a source terminal Et2 and is also connected to one terminal of a switch S2 through a resistor R2. The switch S2 is connected to ground at the other terminal. A proper switching means such as transistor may be employed for those switches S1 and S2.

FIG. 2 illustrates an electrode arrangement of an embodiment according to this invention, in which a plurality of main anode electrodes 11, 12, 21 and 22 are disposed at the lowermost part, a main cathode electrode a is of a plate having a plurality of perforations 11a, 12a, 21a and 22a, each of those perforations are formed so as to aligne with the corresponding main anode electrode. One group of trigger cathode electrodes Y1 and Y2 are disposed under the other group of trigger anode electrodes X1 and X2 to form a matrix. Each of those electrodes has a plurality of perforations 11x, 11y, 12x, 12y, 21x, 21y, 22x and 22y. Those perforations are prepared at the cross points of the matrix. For example, the perforation 12x of the trigger anode electrode X2 and the perforation 12y of the trigger cathode electrode Y1 are formed at the cross point of the cathode electrode Y1 and the anode electrode X2. It is noted that those perforations 12x and 12y, the perforation 12a of the main cathode electrode a and the main anode electrode 12 are aligned in a common axis, and all other perforations formed in those electrodes are aligned with the corresponding the main anode electrodes in this manner. Those perforations aligned in this way form a discharge space, respectively. Although there is no description in the drawing, it should be noted that insulating material occupies the space among those electrodes except the discharge space portions.

In FIG. 3, there is illustrated the change in the voltage Vp between the main anode electrode b and the main cathode electrode a when change in made in the applied voltage therebetween, i.e. the resultant voltage Vq of the source Ea and the source Eb. The voltage Vp may be measured between the point 21p and the main cathode electrode a, for example, in FIG. 1. From the FIG. 3, it may be seen that the voltage Vp increases till the voltage Ez and suddenly decreases to the voltage Eb, as the voltage Vq increases, while the voltage Ez does not change in the value even if the voltage Vq increases. That is, the Ez is a firing voltage and the Eb is a voltage for sustaining a discharge.

The operation of the embodiment of this invention will next be explained with above-mentioned drawings.

The operation of this invention in principle will be descriped with reference to FIG. 1. The inert gas such as argon or neon is provided in the discharge space. The resultant voltage of the sources Ea and Eb is adjusted to a voltage lower than the firing voltage but higher than the discharge sustaining voltage. The trigger anode is impressed with a voltage higher than the firing voltage Ez while the trigger cathode electrode is biased with a predetermined voltage. Under this condition, when the switch S1 is closed a discharge occurs between the trigger electrodes X and Y. This discharge exicites the inert gas in the discharge space which in turn initiates a discharge between the main electrodes. The latter discharge will not cease even if the former discharge ceases. This is a memory function. A display is carried out by the discharge occurring between the main electrodes. A picture element is formed by a main anode electrode and the corresponding charge space which is formed by the perforations of the main cathode electrode and the trigger cathode and anode electrodes.

If the voltage lower than the firing voltage but higher than the discharge sustaining voltage is impressed upon between the trigger electrodes when the main electrodes have a discharge therebetween, the discharge also occurs between the trigger electrodes. However, when no discharge is performed between the main electrodes, even if such value of voltage is impressed upon the trigger electrodes, no discharge occurs between the trigger electrodes. As described in the above, when the discharge occurs, the voltage between the electrodes, at the firing point of the discharge, will breakdown to the discharge sustaining voltage. Consequently, if the voltage between the trigger electrodes is detected by a proper means, it can be detected whether the main electrodes take a discharge or not. In FIG. 1, such detection may be performed by measuring the voltage drop across the resistor R2.

The operation of the embodiment as shown in FIG. 2 will next be described. In the display or write operation, the voltage higher than the discharge sustaining voltage and lower than the firing voltage is applied between the main electrodes, and at the same time some of the trigger electrodes forming matrix, for example, the electrodes Y1, X1 and X2, are energised by an electrical signal higher than the firing voltage Ez. As a result, the discharge occurs between the main anode electrode 11 and the main cathode on the perforation 11a, and occurs between the main anode electrode 12 and the main cathode electrode a at the perforation 12a. Accordingly, the pattern formed by the two discharge dots is obtained. Such pattern remains in display if the electrical signal for the trigger electrodes is removed. In other words, this pattern is at memorized state.

In read-out operation of the information of such pattern, the trigger anode electrodes X1 and X2, and the cathode electrodes, Y1 and Y2 for forming columns and raws, respectively are successively scanned with the electrical signal of the voltage lower than the firing voltage but the discharge sustaining voltage. As in the above description, the voltage between the trigger electrodes is dropped to the discharge sustaining voltage Eb when those electrodes have the perforations corresponding to the now discharging main electrodes. Accordingly, the read-out operation is accomplished by detecting the voltage drop. That is, in this case the voltage drop is found between the electrodes Y1 and X1, and between the electrodes Y1 and X2.

Having described a specific embodiment of our bearing, it is believed obvious that modification and variation of our invention is possible in light of the above teaching.

Claims

1. A cold cathode discharge display apparatus:

a plurality of first electrodes;

second electrode having a plurality of perforations, each of which is arranged so as to substantially confront each of said first electrodes;

a plurality of third electrodes which are arranged in parallel with each other and are oriented in the first direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said second electrodes; and

a plurality of fourth electrodes which are arranged in parallel with each other and are oriented in the second direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said third electrodes;

whereby when the voltage lower than firing voltage but higher than voltage for sustaining the discharge, is applied between said first and said second electrodes and at the same time said third and said fourth electrodes which are properly selected, are energized by an electrical

2. A cold cathode display apparatus as claimed in claim 1, in which said

3. A cold cathode display apparatus as claimed in claim 1, in which one of said perforations of the said first, second, third and one of first

4. A cold cathode display apparatus as claimed in claim 1, in which one of said perforations of the said first, second, third and one of first

5. A cold cathode discharge display apparatus; a plurality of first electrodes;

second electrode having a plurality of perforations, each of which is arranged so as to substantially confront each of said first electrodes;

a plurality of third electrodes which are arranged in parallel to each other and are oriented in a first direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said second electrodes;

a plurality of fourth electrodes which are arranged in parallel to each other and are oriented in a second direction, each of those electrodes having a plurality of perforations substantially aligned with the corresponding said perforations of said third electrodes; and

a voltage detecting means to detect the voltage change between said third electrodes and said fourth electrodes;

whereby when the voltage lower than firing voltage but higher than voltage for sustaining the discharge, is applied between said first and said second electrodes and at the same time said third and said fourth electrodes which are properly selected, are energized by an electrical signal, a proper pattern is formed in display while when the voltage lower than firing voltage but higher than the discharge sustaining voltage is applied between said third electrodes and said fourth electrodes, a

6. A cold cathode display apparatus as claimed in claim 5, in which said second electrode is formed of a plate.