JPH0743577B2 - Dot matrix display - Google Patents

Description

TECHNICAL FIELD The present invention relates to a dot matrix display device such as a thin film EL display and a plasma display.

<Prior Art> A double insulation type thin film EL display device, which is one of dot matrix display devices, is configured as follows, for example.

As shown in FIG. ₂ , strip-shaped transparent electrodes 2, 2 ... Of In ₂ O ₃ etc. are provided in parallel with each other on a glass substrate 1, and an activator such as a dielectric substance 3, Mn etc. of Y ₂ O ₃ etc. is provided thereon. -Doped ZnS EL layer 4, Y ₂ O ₃
Etc. are formed in this order by a vapor deposition method or a sputtering method to a film thickness of 500Å to 10,000Å to form a three-layer structure. Further, the dielectric material layer 5 is orthogonal to the transparent electrodes 2, 2 ... It is a capacitive element in terms of an equivalent circuit, which is formed by providing strip-shaped back electrodes 6, 6 ...

Therefore, by applying a predetermined alternating voltage to the desired transparent electrode 2 and the back electrode 6, the minute area portion sandwiched between the intersections of both electrodes emits light, thereby displaying characters, symbols, patterns, etc. Make up one picture element.

The double-insulation thin-film EL display panel with the above configuration is capable of high-luminance light emission, longer life, and more stable than the conventional dispersed EL display panel. Are better.

In order to maintain the long-term reliability of the EL display device, the visibility of the display, the stability, etc. so as not to impair these characteristics, it is suitable for the number of electrodes on the scanning side and the data side of each EL display panel. Drive logic is required. However, it is disadvantageous to individually design drive logic devices for display panels having different numbers of electrodes from the viewpoint of cost or time constraints required for development when the drive logic device is integrated into an IC. In this regard, the applicant has already been able to apply one driving logic device to many types of EL display devices without changing the hardware, and it is necessary to change the electrode configuration of the display panel. We have proposed a driving logic device for a thin film EL display device with a minimum circuit configuration and general versatility by making a circuit part excluding a certain P-ROM and the like into a single IC.

FIG. 3 shows the structure of this driving logic device. In the figure,
11 is the thin film EL display panel described above, 12 is a scanning side driver group, 13 is a scanning side shift register and latch circuit, 14 is a data side driver group, 15 is a data side shift register and latch circuit, 16 is a modulation circuit and write drive It is a circuit, and each of these 12 to 16 elements constitutes a so-called display drive circuit section.

The portion surrounded by the broken line is the drive logic circuit. 20 is a column counter, 30 is a low counter, 35 is a row number setting switch, 40 is an oscillation circuit, 50 is a synchronizing signal interface circuit, 60 is a data signal interface circuit, 70 is a latch circuit, and 80 is a P-ROM.

The column counter 20 is a circuit that counts the cycle of one row. The period for one row is determined by the frame frequency and the number of electrodes on the scanning side. Normally, the frame frequency is determined by the number of electrodes on the scanning side in order to keep it constant.

Therefore, in order to change the period so that it can be applied to any EL display panel having a different number of electrodes on the scanning side, the oscillation frequency is made constant and the count number of the column counter 20 is changed, or the count number is made constant and the oscillation circuit is made constant. Either the oscillation frequency of 40 needs to be changed.

The number of counts of the row counter 30 must be adapted to the number of electrodes on the scanning side in line-sequential driving.

The outputs of the column counter 20 and the row counter 30 are input to the P-ROM 80 as address data. Therefore, the timing required for one row is generated by the column counter 20, and the timing required for one field is generated by sequentially reading the data of the P-ROM 80 by the row counter 30.

The latch circuit 70 not only latches the output data of the P-ROM 80 for noise removal, but also stops output due to power supply fluctuation.

The sync signal interface circuit 50 is a circuit that secures internal drive timing and synchronizes with a sync signal from the outside. Details are described in JP-A-57-42092.

The data signal interface circuit 60 is an interface for directly controlling the data side shift register / latch circuit 15 in response to external inputs of clock, data, and data valid period signals (also serving as signal H in FIG. 3). Circuit. The details of this are also disclosed in JP-A-57-42092.
It is described in Japanese Patent Publication No.

The low counter 30 does not fix the number of counts, it has a margin in the counter, and by combining it with the row number setting switch 35, the number of counts can be set arbitrarily, and various types of EL
It can be applied to the display panel.

Further, when the count cycle of the column counter 20 and the count number of the row counter 30 are changed, the P-ROM 80 may change the P-ROM data according to it without changing the hardware.

By using such a logic circuit as an IC, the circuit cost can be reduced and the productivity can be improved when the EL display device is mass-produced, and the entire device can be downsized.

<Problems to be Solved by the Invention> In the above-mentioned conventional technique, for an EL panel having a certain number of electrodes on the scanning side, the row number setting switch 35, the P-ROM 80, and the data are fixed. 640 lines x scanning side 4
If you want to display only 640 x 400 using a panel with 80 electrodes, change the line number setting switch 35 and set P-RO.
It was necessary to change the M data and even replace the scanning driver group with one that matched the number of rows. Alternatively,
It was necessary to process the signal externally to display only 640 x 400 lines.

In this way, if you want to use only a part of the scan lines in an EL display device with a large display capacity, you need to change the hardware, which is almost the same as replacing the entire display device, or operate the signal externally. The only way to change it was to change the software. Therefore, there is a problem in terms of cost and use of the device.

<Means for Solving the Problems> The dot matrix display device of the present invention responds to a drive voltage applied between the scanning side electrode and the data side electrode which are arranged to intersect each other and to be opposed to each other. A display panel for executing display, a scan side driver circuit connected to the scan side electrode to apply a writing voltage, a data side driver circuit connected to the data side electrode to apply a modulation voltage, Row number setting switch for setting the number of electrodes on the scanning side, a low counter for counting the number of scanning lines and outputting a timing signal at the end of one field scanning, and the display panel receiving the timing signal In a dot matrix display device including a control drive circuit for controlling the display of, the input signal of one field is counted and the number of scanning lines of the input signal is A scanning line number discriminating circuit for detection is provided, and the row counter counts the number of scanning lines of the input signal detected by the scanning line number discriminating circuit and sets the number of scanning side electrodes of the row number setting switch. When the count ends before,
After that, the control drive circuit outputs a signal to the control drive circuit to stop the supply of the write voltage to the scan side driver circuit up to the set value of the scan side electrode of the row number setting switch. It is attached.

<Operation> When the count of the number of scanning lines of the input signal is finished before the preset value of the number of scanning electrodes is set, the writing is performed in the scanning driver circuit between that time and the preset value. Since no voltage is supplied, no indication is given during that time. Therefore, a signal can be input without being limited by the number of display lines of the display device.

<Embodiment> FIG. 1 shows the configuration of a dot matrix display device of this embodiment. The circuit is basically the same as the circuit of the conventional dot matrix display device of FIG. 3, except that a scanning side line number determination circuit 100 is added. The scanning side line number discriminating circuit 100 gives the control signals A and B to the row counter 30 and the latch circuit 70 in response to the input signals H and V. Further, the P-ROM 80 does not output a signal to the modulation circuit and the writing circuit 16 when specific address data is input from the row counter 30, and the scan side shift register 15
A signal is output only to the device, and data is written so that the transfer is performed about 100 times in a short time. The number of times of this transfer depends on the difference between the actual number of displayable lines and the number of signal lines.

The operation of the scanning side line number determination circuit 100 will be described below.

First, the output A is input to the rich circuit 70 and the output of the latch circuit 70 is stopped for one field after the signal V is input. During this period, the signal H in one field period is counted inside the scanning side line number determination circuit 100 to determine the number of scanning lines of the input signal, and the output B similar to the row number setting switch 35 is output in the next field period. To the low counter 30. The row counter 30 outputs a specific address to the P-ROM 80 when the count number reaches the value of the B input earlier than the set value of the row number setting switch 35, and as described above, the shift register 15 of the scanning side. Only the transfer is performed, and thereafter, the same drive is performed up to the set value of the row number setting switch 35,
Nothing is displayed during this period. Therefore, for example, when 400 lines are input with the number of lines set to 480, nothing is displayed for 80 lines, and the display device can be used as substantially 400 lines.

Although the driving logic circuit of the thin film EL display device has been described in the above embodiment, it goes without saying that the present invention can be applied to a dot matrix type display device having a similar configuration. Further, in the above-described embodiment, the number of lines on the scanning side is only discriminated, but if necessary, it is possible to discriminate on the data side with the same configuration.

<Advantages of the Invention> As described above, according to the present invention, even in a dot matrix display device having a large display dot configuration, a screen having a small dot configuration can be displayed without impairing the display quality, and the dot matrix display device can be displayed. It is possible to enhance the versatility of the above, and it is possible to obtain the advantage that software such as a computer having a relation with the screen configuration can be used as it is without any modification. Further, the present invention can be applied to any display signal in addition to display signals such as personal computer signals and television signals, and in this respect, it is possible to realize a highly versatile device. Further, there is no problem in terms of cost and use.

[Brief description of drawings]

 FIG. 1 is a diagram showing a circuit configuration of an embodiment of the present invention, FIG. 2 is a diagram showing a structure of a thin film EL display panel, and FIG. 3 is a diagram showing a circuit configuration of a conventional example. 11 …… EL panel 12 …… Scan side driver group 13 …… Shift register and latch circuit 14 …… Data side driver group 15 …… Shift register and latch circuit 16 …… Modulation circuit and write circuit 20 …… Column counter 30… … Low counter 40 …… Oscillation circuit 50 …… Synchronous signal interface circuit 60 …… Data signal interface circuit 70 …… Latch circuit 80 …… P-ROM 90 …… Drive logic circuit

Continuation of the front page (72) Inventor Hisami Uede 22-22 Nagaike-cho, Abeno-ku, Osaka-shi, Osaka Within Sharp Co., Ltd. (56) Reference JP-A 61-26083 (JP, A)

Claims (1)

[Claims] 1. A display panel which performs display in response to a drive voltage applied between a scanning side electrode and a data side electrode which are arranged to intersect each other and to face each other, and to the scanning side electrode. A scanning side driver circuit for connecting and applying a writing voltage, a data side driver circuit for connecting to the data side electrode and applying a modulation voltage, and a row number setting switch in which the number of scanning side electrodes for display is set in advance. And a dot-matrix display including a row counter that counts the number of scanning lines and outputs a timing signal at the end of one field scanning, and a control drive circuit that receives the timing signal and controls the display of the display panel. In the device, 1
A scanning line number discriminating circuit for counting the number of input signals of the field and detecting the scanning line number of the input signal is provided, and the row counter is the scanning line number of the input signal detected by the scanning line number discriminating circuit. When the count is finished before the set value of the number of electrodes on the scanning side of the row number setting switch, the control drive circuit is subsequently set to the set value of the electrode on the scanning side of the row number setting switch on the scanning side. A dot matrix display device, which outputs a signal for stopping the supply of a writing voltage to a driver circuit to the control drive circuit.