JPS584964B2 - display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a display device that uses a plasma display to display the magnitude of an analog input signal over the entire range of both positive and negative polarities in the form of a bar graph.

Plasma displays used in this type of display device utilize the fact that an anode and a cathode are sealed in a discharge gas, and when a voltage is applied between the two electrodes, a discharge is generated between the two electrodes, causing the cathode to light up. , a large number of cathodes are arranged on the back sheet surface of the display device at positions corresponding to the display scale, facing each other to the anode of a transparent conductive film formed on the inner surface of the windshield of the display device, and the anode has a time width proportional to the aolog signal level. By applying a pulse voltage and applying a low level (low voltage) to the cathode group from the lowest cathode to the highest cathode in a time-division manner, the number of cathodes that light up is made proportional to the time width of the anode signal, and analog input This displays the signal magnitude in a bar graph.

In order to display an analog input signal with a range of positive and negative polarities using such a plasma display, the center of the display screen is set as the zero point, and the cathode groups above or below the zero point are set to the input signal level depending on the positive or negative polarity of the analog input signal. A so-called zero-center indicator can be considered, which also displays positive and negative values by lighting a number proportional to .

By the way, some plasma display devices are of a self-scan type, which makes it easy to drive the cathode.

This self-scanning plasma display utilizes a discharge transition that allows only the cathodes adjacent to the already lit cathodes to light up even when a pulse voltage is applied to multiple cathodes for lighting. By dividing the cathodes into groups so that they belong to different groups, pulling out the cathodes of the same group as a common cathode terminal, and sequentially driving the cathode terminals of each group, the cathode groups are lit in a time-divisional manner from the lower to the upper. can be done.

As a result, the cathode can have a minimum of three external lead-out terminals, and its drive circuit can also have a simple configuration that generates three-phase pulse voltages.

In order to construct the above-mentioned zero center display using such a self-scan type plasma display, a special display and drive circuit are required, resulting in a problem of high cost.

An object of the present invention is to provide a display device that can display both the positive and negative polarities of an input signal using a general self-scan type plasma display, and can also obtain the effects described later.

In this invention, a self-scan type plasma display displays the absolute value of the input signal, and a polarity sign display provided near the display indicates the positive value of the input signal.

Negative values are displayed as signs.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the display section in this invention.

The plasma display Dp is a self-scanning type, with the input signal level at 0% at the lowest level of the cathode and 100% at the highest level, and the absolute value of the input signal is determined by lighting the number of cathodes proportional to the input signal level. Display as a bar graph.

The polarity code display Dpc displays the polarity of the input signal by causing one of the positive polarity display Dpc and the negative polarity display DP0 disposed near the plasma display DP to emit light.

A light emitting element such as a light emitting diode can be used as the polarity code display Dpc, but the plasma display DP itself can be provided with a polarity code display.

That is, the plasma display is equipped with a cathode configured in the shape of a polarity code and an anode (integrated with the anode for absolute value display) opposed to the cathode, and the polarity can be determined by selectively driving the cathode according to the polarity of the input signal. Can be displayed.

In addition, when setting the polarity sign to (+) and (-), configure the (+) shape with multiple cathodes, and selectively drive the cathodes (
It is also possible to switch between +) display and (-) display.

This can equally be applied to a display using a light emitting diode or the like.

FIG. 2 shows an embodiment of the drive section in this invention.

As shown in FIG. 5, the double integration type analog-to-digital converter AD includes an integrator 1, a comparator 2, a counter 3,
It has a built-in switch drive circuit 4.

Built-in counter 3 is connected to clock generator CL through terminal f.
Count the clocks from K.

A certain period of time TM from the start of conversion until the counter 3 reaches a certain count value is a control output of a built-in switch drive circuit 40 and is connected to a switch element S via a terminal.

Turn on.

As a result, the built-in integrator 1 integrates the analog input signal Ein for the time TM through the resistor R6 and the terminal a.

A comparator 2 is connected to the output of the integrator 1, and the comparator 2 compares the zero potential with the output of the integrator 1, determines whether the polarity of the analog input signal Ein is positive or negative, and sends the signal to the switch drive circuit. 4. The switch drive circuit 4 operates for a certain period of time T in accordance with the positive/negative determination signal of the analog input signal Ein.
After M time integration, switch element S is connected via terminal d or e.
1 or S2 is turned on, and the switch element S is connected through the terminal.

is turned OFF, and the reference voltage +Es or -Es, which has the opposite polarity to the analog input signal Ein, is applied to the integration input of the integrator 1 through the resistor R1 or R2 and the terminal C.

As a result, the output of the integrator 1 is as shown in FIG.
The comparator 2 detects that the TM time integral value of the analog input signal Ein is subtracted and integrated toward the zero point, and that the zero potential has been reached.

Upon this detection, the switch drive circuit 4 turns off the switch element Sl or S2, and turns off the switch element S.

is turned ON to start integrating the analog input signal Ein again.

At the same time, the counter 3 starts clock counting via the terminal f to obtain the output of TM for a certain period of time.

Therefore, the integration time Tx from the end of the TM time integration of the input signal Ein to the zero detection of the comparator 2 is proportional to the magnitude of the analog input signal Ein.

This time Tx corresponds to the time when the switch S1 or S2 is turned on, and therefore the switch drive circuit 4 also outputs the analog-to-digital converter AD through the terminal g for the integration time Tx.
A pulse having a time width of is output, and this pulse is applied to the anode voltage of the plasma display DP through the anode driver DA.

In Fig. 3, So, Sl, and S2 are switch elements S, respectively.

, Sl. The ON and OFF states of S2 are shown.

On the other hand, the clock of the clock generator CLK is input to the converter F, and the converter F converts it into an N-phase clock corresponding to the number N of cathode terminals of the plasma display DP.

This N-phase clock sequentially drives the grouped cathodes of the plasma display DP through the cathode driver DK.

Therefore, in the plasma display DP, as shown in FIG.
The absolute value of in can be displayed as a bar graph.

The polarity is indicated by a switch element S at the terminal d or e of the analog-to-digital converter AD depending on the polarity of the input signal Ein.
Since the signal to turn on 1 or S2 is output,
This signal is passed through resistors R3 and R4 to a light emitting element (light emitting diode in the case shown) for polarity display Dpc+ or Dpc.
This can be done by lighting -.

Note that in order to change the display span on the plasma display DP according to the polarity of the input signal Ein, the reference voltage +
This can be done by changing the value of Es or -Es depending on the desired span, or by changing the resistance value of resistor R1 or R2.

FIG. 4 shows a case where the instruction span is set to 1:2, and the scale is set according to positive and negative polarities.

As explained above, the present invention uses a self-scan type plasma display to display the absolute value of an input signal as a bar graph, and uses a polarity code display to display the polarity of the input signal, which simplifies the drive circuit for the plasma display. , an ordinary plasma display can be used, and its cost can be reduced.

In addition, the full scale of the input signal is doubled compared to the zero center display, making it possible to increase its indication accuracy (determined by the number of cathodes per unit length), or to make it easier to read the displayed amount with the same indication accuracy. There is a certain effect.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the display section in this invention,
FIG. 2 is a block diagram showing one embodiment of the driving section in this invention, FIG. 3 is a time chart for explaining the operation of FIG. 2, and FIG. 4 is a block diagram showing another embodiment of the display section in this invention. The figure shown in FIG. 5 is a circuit diagram showing a specific example of the main part of the present invention. DP: Plasma display, Dpc: Polarity code display, AD
:Analog-digital converter, DA near note driver, DK: cathode driver, CLK: clock generator,
F: Converter.

Claims (1)

[Claims] 1. A large number of cathodes are arranged at positions corresponding to the display scale, and a pulse voltage with a time width proportional to the analog input signal is applied to the anode. There is a self-scanning plasma display DP that can display the magnitude of an analog input signal in a bar graph by sequentially applying the voltage for lighting up to the cathode, and a self-scanning plasma display DP that can display the polarity of the analog input signal by placing it near the plasma display. A polarity sign indicator Dpc that can be displayed, an analog input signal Ein and a first reference signal 10Es of positive polarity or a second reference signal -Es of negative polarity are respectively connected to the switch element S. , Sl, S2, which first integrates the analog input signal and then integrates the first reference signal or the second reference signal with the opposite polarity thereto; A comparator 2 outputs a signal for determining whether the analog input signal is positive or negative by comparing it with zero potential, and a first comparator whose polarity is opposite to that of the analog input signal based on the comparator output.
a switch drive circuit 4 that controls the switch element so that a reference signal or a second reference signal is provided to the integrator;
When the integrator output reaches zero potential, clock counting is started based on the comparator output, and for a certain time TM until the count value reaches a constant count value, the clock is applied to the integrator via the switch drive circuit. a counter 3 for receiving an analog input signal; and a converter F for converting the clock into a multi-phase clock and applying it to the cathode of the plasma display; A pulse having a time width corresponding to the time Tx during which the reference signal is applied is supplied to the anode of the plasma display to display the absolute value of the analog input signal on the plasma display, and the first reference signal Alternatively, the display device is characterized in that the output of the switch driving circuit for supplying the second reference signal to the integrator is applied to the polarity sign display to display the polarity of the analog input signal.