JPH0682262B2 - Plasma display device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a plasma display device.

[Conventional technology]

A conventional plasma display device will be described with reference to FIG. The plasma display panel 1 includes m row electrodes 2 _{1 to} 2 m parallel to each other and n column electrodes 3 ₁ to 3 parallel to each other arranged in a matrix to face each other.
It has 3m and 4 display cells at each of the matrix intersections.
Are formed. The scanning signal unit 9 includes a clock generator 8
The clock pulse a is input to generate a scanning signal b having a constant cycle in synchronization with the clock pulse a. Row control unit 11, the row electrodes 2 ₁ to
The output lines corresponding to 2 m are connected to the row driver 5 and the scanning signal b is input from the scanning signal section 9 to sequentially scan the row driver 5. Row driver 5, the output terminal of the row electrodes 2 ₁ to
The discharge pulse c is input from the discharge pulse generator 7 to be connected to each 2 m, and the corresponding row electrodes 2 _{1 to} 2 m are discharged during the period of being scanned by the row controller 11. The discharge pulse c is stepped up and applied to a voltage required for the above. The data control unit 12 is connected to the column driver 6 through output lines corresponding to the column electrodes 3 _{1 to} 3 n, and the input data d output from the input data unit 10 is the row electrodes 2 ₁ to 3 n.
Each time a clock pulse a is input in response to a scan of 2 m, it is input to the data control unit 11, where it is arranged as a signal to the corresponding row electrode and output to the output line to the corresponding column driver 6. The column driver 6 inputs the output of the data controller 12 and the discharge pulse c, and applies the discharge pulse c to the selected column electrode by stepping up to the voltage required for discharging. In this case, since the discharge voltages applied to the corresponding row electrodes and column electrodes are controlled so as to have opposite phases to each other, the discharge voltages are additively applied to the display cells 4 at the intersections of both electrodes, and the display cells 4 are displayed. The cell 4 becomes higher than the discharge disclosed voltage and discharges light.

As described above, the scanning of the row electrodes 2 _{1 to} 2 m and the input timing of the input data d to the column electrodes 3 ₁ to 3 n are synchronized, and the column electrode corresponding to the row electrode to be scanned is selected according to the input data d. By controlling, the display cell 4 corresponding to the input data d on the plasma display panel 1 can be made to emit light. The emission brightness at this time depends on the frequency of the discharge pulse c output from the discharge pulse generator 7.

[Problems to be solved by the invention]

In the above-described conventional plasma display device, since the discharge pulse generator constantly generates the discharge pulse regardless of the scan signal, the number of discharge pulses applied during the scanning period of each row electrode is determined by the scan signal and the discharge pulse. 1 due to the phase relationship of
There may be one or two changes, in this case,
Since the light emission brightness of the display cell is proportional to the number of discharge pulses, it has the disadvantage that it appears as stripes of brightness unevenness in the scanning direction to the human eye. Furthermore, when the brightness is controlled from the outside, the discharge applied to both matrix electrodes Since the frequency of the pulse is changed, there is a drawback in that the above-mentioned stripes of uneven brightness similarly occur.

[Means for solving problems]

The plasma display device of the present invention counts the number of discharge pulses output for each one scanning period of the row electrode, and when the count value reaches a set value, stops the output of discharge pulses after that and outputs the count value. It has a pulse control unit for clearing and a setting unit for setting the set value of the discharge pulse in the pulse control unit.

In this way, the number of discharge pulses applied to the row electrodes and the corresponding column electrodes during one scanning period can be preset and kept constant, so that the light emission of the display panel causes stripes due to uneven brightness. Absent. Further, even if the emission brightness is changed from the outside, it is possible to prevent stripes due to uneven brightness from occurring.

〔Example〕

 Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the plasma display device of the present invention.

In this embodiment, a pulse number setting unit 13 and a pulse control unit 14 are installed in the conventional device described with reference to FIG. The pulse number setting unit 13 outputs a preset signal e using a volume or the like, and presets the number of discharge pulses c to be output by the pulse control unit 14 during one scanning period. The pulse control unit 14 inputs the scan signal b and the discharge pulse c, counts the discharge pulse c input from the start of scanning by the scan signal b, and outputs the pulse to the row driver 5 and the column driver 6 and outputs the same. When the number of the discharge pulses c becomes equal to the value set by the preset signal e, the output of the subsequent discharge pulses c is stopped and the count value is cleared,
The same operation is repeated for each scanning period.

In this way, the number of discharge pulses in one scanning period of the display cell 4 is always held at the preset value e, so that stripes do not occur and the brightness can be controlled without causing uneven brightness.

〔The invention's effect〕

As described above, the present invention presets the number of discharge pulses output during one scanning period of each row electrode by using the pulse control unit and the setting unit that sets the count value of the discharge pulse in the pulse control unit. By keeping the value constant corresponding to the set value, it is possible to control the brightness without causing stripes due to uneven brightness and without causing stripes due to uneven brightness.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the plasma display device of the present invention, and FIG. 2 is a block diagram showing a conventional plasma display device. 1 ...... plasma display panel, 2 ₁ to 2 m ...... row electrodes, 3 ₁ 3n ...... column electrodes, 4 ...... display cells, 5 ...... line driver, 6 ...... column driver, 7 ...... discharge pulse generating unit , 8 ... Clock generator, 9 ... Scan signal part, 10 ... Input data part, 11 ... Line control part, 12 ... Data control part, 13 ... Pulse number setting part, 14 ... Pulse control part , A ... Clock pulse b ... Scan signal, c ... Discharge pulse, d ... Input data, e ... Preset signal.

Claims (1)

[Claims] 1. A display cell formed by a plurality of row electrodes and a plurality of column electrodes facing each other in a matrix at an intersection thereof, the row control unit synchronizing with a clock pulse. During the period of scanning with the generated scan signal, the corresponding row electrode is applied with the discharge pulse, and the data control unit reads the input data every time the clock pulse is input, and the column electrode corresponding to the input data is selected. In the plasma display device in which the display cells discharge and emit light to display characters and figures corresponding to the input data by applying discharge pulses, the number of discharge pulses output for each scanning period of the row electrodes is displayed. The pulse control unit that counts and stops the discharge pulse output after that count value reaches the set value and clears the count value, and the pulse control unit A plasma display apparatus characterized by comprising a setting means for setting the set value.