JPS6346435B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a display control system for a plasma display panel used as a display for information processing terminal equipment. The purpose is to prevent display errors due to cell ignition failure.

For example, as shown in FIG. 1, a plasma display panel has X electrodes X ₁ , X ₂ . . . X _o and Y electrodes Y ₁ , Y ₂ . A discharge cell for displaying character information, etc. is formed at the opposite intersection with Y _o . In the mask area 2 outside the window frame 1, between the pilot electrodes _P1 to _P8 , as well as between the pilot electrodes _P1 to _P8 , the X electrodes _X1 to _Xo , and the Y electrode _Y1.
A discharge cell for pilot fire is formed at the intersection with ~ _Yo . As shown in FIG. 2, the structure of each of these discharge cells includes X electrodes x ₁ , x _{2 .} . . and Y electrodes y _i (i=1, …)
are arranged facing each other, and each electrode x ₁ , x _{2 .} . . y _i is covered with a dielectric layer 5, 6. A gas-filled gap 7 between the dielectric layers 5 and 6 is filled with a discharge gas such as argon or neon. Due to this structure, the cell portion in which the X-side electrode and the Y-side electrode face each other with a gap 7 in between and intersect with each other can be expressed as an equivalent circuit as shown in FIG. That is, the equivalent capacitances Cx and Cy formed in the dielectric layers 5 and 6 and the discharge cells formed in the gas-filled gap 7 form a series circuit.

By applying, for example, an alternating current voltage between each of these electrodes x ₁ , x _{2 .} . . and y _i , the discharge cell C ₁ in the gas-filled gap 7 is
When a voltage higher than the discharge starting voltage is applied to..., the discharge cells _C1 ... are discharged, and electrons and ions are generated in the gas-filled gap 7. Then, electrons move toward the electrode to which a positive voltage is applied, and ions move to the electrode to which a negative voltage is applied. As a result, dielectric layers 5, 6
The inner walls of the dielectric layers 5 and 6 are charged by the charged particles, and a wall voltage is generated on the inner walls of the dielectric layers 5 and 6 with a polarity opposite to that of the externally applied voltage. Therefore, discharge cell C ₁
...The voltage at both ends becomes below the discharge sustaining voltage, and the discharge stops.

By the way, since the resistance values of the dielectric layers 5 and 6 are extremely high, the charges generated on the inner walls of the dielectric layers 5 and 6 remain without being attenuated. Therefore, when a voltage of opposite polarity is next applied between the electrodes x ₁ , x _{2 .} . . and y _i , the sum of the applied voltage and the wall voltage is equivalently equal to the sum of the applied voltage and the wall voltage of the discharge cell C ₁ .
is applied to When this voltage sum is higher than the discharge start voltage of the discharge cells C _{1 .} . . , discharge occurs again.
Therefore, by repeating such operations, discharge can be maintained continuously for a long time.

In this way, the discharge cell discharges when a voltage equal to or higher than the discharge starting voltage (V _F ) is applied between its electrodes. Actually, X electrodes X ₁ and X ₂ for character information display
A discharge _sustaining voltage _{(V S ) is} always applied to _{the ...} hand,
By making the voltage sum higher than the discharge starting voltage (V _F ), the selected electrode is caused to discharge.

On the other hand, a voltage higher than the discharge starting voltage (V _F ) is constantly applied to the pilot discharge cell to keep the display area 1 of the panel P in an ionized state, and the discharge cell for displaying text information, etc. The pilot flame effect makes it easy to discharge. However, when power is turned on to panel P, there are few ions, electric charges, etc. that become the core of discharge, so the discharge of the pilot discharge cell does not occur smoothly, and various fire discharges may occur depending on the panel or within the same panel. Since there are variations in the discharge starting voltage (V _F ) depending on the cell, the pilot discharge cell may not discharge at a certain set level of discharge starting voltage (V _F ), and the pilot discharge cell may not be reliable. If a write voltage (V _W ) is applied to a discharge cell for displaying character information before it is discharged, the display discharge cell will not be discharged, resulting in a display error.

On the other hand, as described in Japanese Patent Publication No. 55-20594, a method is known in which a high voltage is applied to the pilot discharge cell when the power is turned on, and a discharge sustaining voltage is applied after a predetermined period of time. However, this method does not directly detect pilot discharge, but instead predicts pilot discharge indirectly based on the elapsed time after the power is turned on, and switches to the discharge sustaining voltage. Therefore, due to a malfunction of the timer function that detects the elapse of a predetermined period of time, etc., the pilot flame may not be discharged properly before it is discharged.
There is a risk of switching to the discharge sustaining voltage. Further, even if the timer function is normal, the time until the pilot discharge occurs will vary due to fluctuations or variations in the discharge generation conditions in the pilot discharge cells.
As a result, when display information is input with insufficient pilot discharge, a display error occurs.

The technical problem of the present invention is to solve such problems and to ensure that the display operation is performed after the pilot discharge is performed irrespective of the elapsed time. The purpose is to prevent errors in displaying information due to incorrect ignition.

In order to solve this technical problem, the technical means of the present invention includes a display discharge cell to which predetermined data is supplied and displayed, and a pilot discharge cell that facilitates discharge of the display discharge cell. In the plasma display panel, a means is provided for detecting that a pilot discharge cell has reached a proper discharge state and outputting an information receivable signal, and displays the data to be displayed using the information receivable signal. A method is adopted in which the energy is supplied to the discharge cells.

Next, an embodiment of the plasma display unit control method according to the present invention will be described with reference to the drawings.

FIG. 4 is a circuit diagram showing a first embodiment according to the present invention. Between the pilot electrodes P ₁ and P ₂ , discharge cells C ₁ , C ₂ , . . . C _o for pilot lights are connected. Transistors Tr ₁ to _{Tr 4} are switched by input signals from input terminals T ₁ to _{T 4} , respectively. Then, a voltage higher than the discharge starting voltage (V _F ) necessary to discharge the discharge cells C ₁ , C _{2 .} . . C _o is applied to the transistors Tr ₁ to
By switching Tr ₄ , a voltage is applied from the power terminal 8 between the pilot electrodes P ₁ and P ₂ . The terminal T ₅ connected to the emitter of the transistor Tr ₂ is connected to the discharge cell C ₁ ,
C ₂ ... When C _o discharges and the discharge current flows through the transistor Tr ₂ , the resistance R and the capacitor C
This is a terminal for detecting a change in the potential of the emitter of the transistor _Tr2 according to a time constant, and is connected to the level detection hold circuit 9. When the voltage at the terminal _T5 reaches or exceeds a certain set level, the level detection and hold circuit 9 holds that level and sends out an information receivable signal from the output terminal _T6 . It is not until this receivable signal arrives that the display information on the panel can be received.

Note that a signal synchronized with the discharge sustaining voltage (V _S ) applied to the display discharge cells is input to the input terminals T ₁ to _{T 4} .

Next, the operation will be explained. First, each input terminal
When a high level "1" pulse is input to _T1 to _T4 , the pulse to the input terminal _T1 is inverted to "0" via the inverter 11, and the transistor _Tr1
turns on. The pulse to the input terminal _T2 is also inverted to “0” via the inverter 12, and the transistor
Tr ₂ turns OFF. On the other hand, a "1" pulse to input terminals T ₃ and T ₄ turns off transistor Tr ₃ .
Turn on transistor Tr ₄ . Therefore, a voltage equal to or higher than the discharge starting voltage (V F ) is applied between the pilot electrodes P ₁ and P ₂ by a loop via the transistor Tr ₁ and the transistor Tr ₄ , and a voltage higher than the discharge starting voltage (V _F ) is applied between the pilot electrodes P ₁ and P ₂ .
…C _o discharges. At this time, a small charging current shown at a in FIG. 5A flows through the emitter side of the transistor _Tr2 .

Next, when the polarity of the pulse applied to the input terminals T ₁ to _{T 4} is reversed, “0” is applied to the input terminals T ₁ and T ₂ .
The pulses are inverted to "1" via inverters 11 and 12, respectively. Therefore, transistor Tr ₁
is turned OFF, and transistor Tr ₂ is turned ON. On the other hand, due to the "0" pulse to the input terminals T ₃ and T ₄ , the transistor Tr ₃ is turned on, and the transistor Tr _{4 is} turned on.
is turned off. As a result, a voltage equal to or higher than the discharge starting voltage (V _F ) is applied between the pilot electrodes P ₂ and P ₁ with the opposite polarity to that in the above case through the loop via the transistors Tr ₃ and _Tr 2. , each discharge cell C ₁ , C ₂ . . . C _o discharges again. At this time, the resistor R on the emitter side of the transistor Tr ₂ and the capacitor C form a loop through which the discharge current of each discharge cell C ₁ , C _{2 .} . . A discharge current flows. Therefore, as the discharge by each discharge cell C ₁ , C _{2 . .} . going up. When the voltage across the capacitor C exceeds the level preset in the level detection and hold circuit 9, a high level signal as shown in Figure C is output from the output terminal _T6 . This signal indicates the receivable state of information to be displayed.

Note that a 4-input AND gate corresponding to the various fire electrodes P ₁ , P ₂ , P ₃ , P ₄ , P ₅ , P ₆ , P ₇ , and P ₈ is provided after the level detection hold circuit 9, and It is also possible to send out the receivable signal after all the pilot electrodes are in a proper discharge state by logically ANDing the receivable signals from the .

FIG. 6 is a block diagram showing a second embodiment according to the present invention. P ₁ and P ₂ are pilot electrodes, and discharge cells C ₁ , C ₂ . . . C _o for pilot lights are connected to both ends of the pilot electrodes. 20 is a discharge cell between the pilot poles P ₁ and P ₂ .
C ₁ , _{C 2 .} . . This is a cell drive circuit for applying a voltage higher than the discharge starting voltage (V _F ) of Co. 21 is a phototransistor provided at a position suitable for receiving light from the discharge of pilot discharge cells C ₁ , C ₂ . . . C _o , and V _B is its power source. Reference numeral 22 denotes an amplifier for amplifying the electrical signal to a specified level when the optical signal is converted into an electrical signal by the phototransistor 21. 23 is a level detection hold circuit for holding the level of the signal output from the amplifier 22 if it reaches a specified level and sending out a signal that allows writing. In this configuration as well, the phototransistor 21, which is a light receiving element, detects that the pilot discharge cells C ₁ , C _{2 .} . . As the cell reaches a state where it is easy to discharge,
Only when the receivable signal outputted from the level detection and hold circuit 23 arrives, information to be displayed on the panel is received, and the panel is driven to perform display.

As explained above, according to the present invention, the discharge cell for the pilot fire is reliably ignited, and the display area of the panel is ionized by the discharge gas caused by the pilot fire.
Since display information for driving the display discharge cells to perform display can be received after the display discharge cells are in a state where they are easy to discharge, mistakes in displaying information immediately after initial ignition can be prevented. Ru.

In particular, in the present invention, regardless of the elapsed time after the power is turned on, display information is displayed after detecting whether a pilot discharge has actually occurred and confirming that the display discharge cells can be driven. Since the information is received, there is no fear of display errors due to fluctuations in the timer function or pilot discharge start conditions, unlike in the past, and the reliability of the display operation is extremely high.

[Brief explanation of the drawing]

FIG. 1 is a perspective plan view of a plasma display panel, FIG. 2 is a partially enlarged sectional view of FIG. 1, and FIG. 3 is an equivalent circuit diagram between electrodes. 4 to 6 show embodiments of a display control system for a plasma display panel according to the present invention. FIG. 4 is a circuit diagram showing the first embodiment, and FIG. 5 shows the various parts of FIG. FIG. 6 is a block diagram showing the second embodiment. In the figure, P is a display panel, X ₁ ~
X _o is an X electrode, Y ₁ to _{Y o} are Y electrodes, P ₁ to _{P 8} are pilot electrodes, C ₁ to _{C o} are discharge cells, Tr ₁ to _{Tr 4} are transistors, C is a capacitor, and 9 and 23 are A level detection hold circuit, 20 a cell drive circuit, and 21 a phototransistor.

Claims (1)

[Claims] 1. In a plasma display panel having a display discharge cell to which predetermined data is supplied and displayed, and a pilot discharge cell to facilitate discharge of the display discharge cell, the pilot discharge cell is brought into an appropriate discharge state. A display control method for a plasma display panel, characterized in that a means is provided for detecting that the information has been reached and outputting an information receivable signal, and supplies data to be displayed to a display discharge cell using the information receivable signal. .