JPS6015185B2 - fluorescent display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an optical display device that uses a poppy and a light body in a unit picture element for image display, and more particularly to an excitation drive method for the poppy and the light body.

BACKGROUND OF THE INVENTION Optical display devices, such as color cathode ray tubes, are widely used for receiving television broadcasts and in terminal equipment for various information processing devices.

However, the desired performance for this type of display is high brightness,
The goal is to achieve high-resolution images and increase efficiency. The present invention proposes an effective optical display device that achieves the above object, and the details of the present invention will be summarized below with reference to an embodiment of a color cathode ray tube.

．． According to the inventor's experiments, when a poppy for color cathode ray tubes and a light body, especially a poppy and a light body with a zinc sulfide base, are excited by an electron beam and emit light, their luminous properties are as shown in FIG. In response to a predetermined excitation pulse signal 1, a light emission waveform 2 having transient characteristics is exhibited, and a far rising portion and a slow falling portion are observed before and after the brightness saturation portion.

Therefore, by utilizing this phenomenon, the excitation signal for the poppy/light body is temporarily accumulated and held, and this is converted into a signal within the same time width, thereby shortening the excitation time per time to 1/n, and n
If you repeatedly make the same poppy and excite the light body,
Of the above-mentioned light emitting characteristics, light is emitted in the slow falling portion, which becomes more effective and enables high-brightness display. FIG. 2 is a block diagram of an optical display device having means for holding an excitation signal for a predetermined time and converting the excitation signal as described above. electrode) 4, shift register 5,
A time-series video signal is applied from an input terminal 9 via a buffer memory 6 as a holding means, a shift register, and a video amplifier 8.

The shift register 5 time-divides (samples) the video signal applied to the input mode 9 using a sampling pulse applied to a terminal 10 and a clock pulse applied to a terminal 11, and transfers this sampled video signal to the buffer memory 6. send to Thus, the buffer memory 6 stores and holds charges corresponding to the sampled video signal in its internal semiconductor memory element.
These operations are performed within the first horizontal scanning period. Next, during the first blanking period, both the operation of transferring the memory contents of the buffer memory 6 to the shift register 7 and the operation of erasing the memory contents of the buffer memory 6 are performed.

Then, during the next second horizontal scanning period, a clock pulse having a repetition frequency n times (n is an integer) the clock pulse of the shift register 5 is applied to the terminal 12 as a clock pulse of the shift register 7. The output of the shift register 7 is sent to the input terminal 4 of the color cathode ray tube 3 through a video amplifier 8 having a bandwidth at least n times that of the video signal.

During this time, by applying a deflection current of n times the frequency to the horizontal deflection coil 13 of the color cathode ray tube 3, the electron beam density per unit time for each picture element on the image display surface of the color cathode ray tube 3 is increased. That is,
1 of the same electron beam while keeping the excitation energy density constant.
The residence time in a pixel per cycle can be shortened to 1'n, and excitation light emission is repeated n times during one horizontal scanning period. Thus, in each horizontal scanning period and each blanking period, the circuit operations of the first horizontal scanning period and the first blanking period are repeated.

FIG. 3 is a circuit diagram showing an embodiment of the present invention, including time division means for time-series video signals for one picture element, holding means therefor, and signal conversion means.

To describe the circuit configuration shown in FIG. 3 in correspondence with FIG. 2, first, the shift register 5 (FIG. 2) has a JK flip-flop 14 as its basic configuration, and the input terminal 1 A predetermined sampling pulse is applied to the terminal 11, and a clock pulse corresponding to the number of picture elements (number of rows) in the horizontal direction is applied to the terminal 11. JK flip flop 14
The output terminal Q is connected to the drain electrode of an insulated gate field effect transistor (hereinafter abbreviated as MOS transistor) 15, to which the time-series video signal from the terminal 9 is input. The above-mentioned time-series video signal time division means is composed of a JK flip-flop 14 and a MOS transistor 15. The structure of the buffer memory 6 (FIG. 2) serving as the holding means is as follows.

The source electrode of the MOS transistor 15 is connected to the load resistor 16
is connected to ground via a high-resistance bias resistor 18 and a bias power supply 2 via a coupling capacitor 17.
0, the gate electrode of the MOS transistor 21, and the drain electrode of the MOS transistor 22, respectively. Further, the source electrode of the MOS transistor 21 is grounded via a load resistor 23, and connected to the series connection body of a high-resistance bias resistor 25 and a bias power supply 26 via a coupling capacitor 24, and the gate electrode of the MOS transistor 27. , MOS transistor 2
8 drain electrodes, respectively. Furthermore, the main component of the shift register (FIG. 2) as a signal conversion means is a charge-coupled device (hereinafter abbreviated as CCD) 29.
Each transfer element 291, 292, 2 of the CCD 29
Three-phase transfer signals are applied to each gate electrode 93.

The drain electrode of the MOS transistor 27 is connected to a high constant voltage source via the MOS transistor 30, and the gate electrode terminals 12 of the MOS transistor 30 are connected to
A clock pulse having a repetition frequency n times the frequency of the clock pulse applied to terminal 11 is applied. C.C.
The output signal of D29 is output from terminal 31. Note that the terminals 32 and 33 are connected to a low potential point for erasing the charge stored in the buffer memory 6, and this erasing operation is performed by an erasing pulse applied to the terminals 34 and 35.

The operation of the embodiment having the above configuration will be described below.

The output terminal Q of the JK flip-flop 14 is the terminal 10,1
1 is held at a positive potential only for a time period determined by the sampling pulse and clock pulse applied to the MOS transistor 15, and generates a positive pulse voltage corresponding to the level of the video signal applied to the terminal 9 at the source electrode of the MOS transistor 15, This pulse voltage is connected to a capacitor 17 and a high bias resistor 18.
and hold it. Such operations are sequentially performed for each JK flip-flop 14 within the first horizontal scanning period,
Each capacitor 7 and each resistor 18 hold the time-divided video signal. The following operation is performed within the first horizontal retrace period.

Each capacitor 17 and each A pulse voltage corresponding to each level of the signal held by the resistor 18, that is, a time-divided signal applied to the gate electrode of each MOS transistor 21, is simultaneously generated in each resistor 23, and this pulse voltage is It is held by a capacitor 24 and a high resistance 25. This held voltage will be applied to the gate electrode of MOS transistor 27. Thereafter, by applying an erase pulse to the terminal 34, the charges held in each capacitor 17 and each resistor 18 are simultaneously erased via each MOS transistor 22. By the way, each capacitor 2
The voltage held by each capacitor 24 and each high resistance 25 is transferred and outputted by the CCD 29 during the second horizontal scanning period, but after this transfer operation is finished, the voltage is held by each capacitor 24 and each high resistance 25. It is necessary to erase the voltage that is generated.

This erasing operation is performed via the MOS transistor 28 by applying an erasing pulse to the terminal 35.
During the next second horizontal scanning period, each picture element arranged in one row on the image display surface of the color cathode ray tube is repeatedly scanned n times.

Note that one period obtained by dividing this one horizontal scanning period into n equal parts is called 1
/n scan period. That is, by applying a short pulse signal with a repetition frequency n times the horizontal scanning frequency to the terminal 12 within one horizontal scanning period, M
The OS transistor 30 is made conductive n times, and the charge corresponding to the signal voltage level held in each capacitor 24 and each high resistor 25 is transferred to the CC via the MOS transistor 27.
Inject into each transfer element 293 of D29. After that, 1/n
Charges injected into the transfer element 293 within the 1'n scanning period are sequentially transferred to the transfer elements 292 and 291 using three-phase clock pulses having a repetition period equal to the scanning period divided by the number of picture elements on one horizontal scanning line. Then, a time-divided video signal is obtained at the output terminal 31. In this way, during the second horizontal scanning period, charges corresponding to the voltage levels held by the capacitor 24 and the resistor 25 are injected n times into the CCD 29, and
A signal is output from the CCD 29 every 1'n scanning period to scan the picture element n times.As a result, the excitation energy density to each picture element is constant, and the excitation time per time for each picture element is It is abbreviated.

As described above, the first horizontal scanning period, the first horizontal retrace period, and the second
The operations described for the horizontal scanning period are summarized as follows for the first horizontal scanning period and one flyback period. {
1} The operation of time-divisionally storing the horizontal scanning period video signal in the buffer memory 6 and the operation of outputting the previous horizontal scanning period signal held in the buffer memory 6 via the CCD 29 are performed simultaneously.

[21 In the horizontal retrace period buffer memory 6, the operation of erasing the signal held by the capacitor 24 and the high resistance 25 during the previous horizontal scanning period, and the signal held by the capacitor 17 and the high resistance 18 The operation of holding the signal by the capacitor 24 and the high resistance 25 and the operation of erasing the signal held by the capacitor 17 and the high resistance 18 are sequentially performed.

In this example, the video signal is 15.75×50 HZ
The luminous efficiency of the color cathode ray tube can be increased by 40% by scanning each pixel three times in one horizontal scanning period using the time-divided video signal.
We were able to improve the brightness and increase the brightness by 40%.

Considering this result, it can be understood that the light emission due to the slow falling part of the light emission characteristics of the phosphor of each feeding element acts more effectively on high-intensity display. FIG. 4 is a block diagram showing another embodiment of the present invention.
This figure shows a method in which a video signal is selectively applied to the signal input terminal 4 by a switching circuit 40.

That is, according to this configuration, the video signal is held and delayed for one horizontal scanning period by the delay circuit 41 serving as a holding means, and the normal video signal and the delayed video signal are transferred to the switching circuit 4. In addition, within the switching circuit 40, the phase shifted 2
Both of the above video signals are selected by two gate signals (a, b), and when a normal video signal is input, the gate signal a
is activated, and gate signal b is activated for input of delayed video signal.
is activated. At this time, the vertical deflector 42 of the cathode ray tube 3
For the vertical deflection current 4 as shown in FIG.
2, the electron beam is sequentially meandered over the screen surface to perform high-speed scanning. As a result, in one horizontal scanning period, the picture elements arranged in two rows are switched and scanned in a very short period of time, so each picture element is excited twice in one horizontal scanning period, and the excitation energy to each picture element is reduced. The density is constant, and each picture element is scanned by shortening the excitation time per time. Therefore, the energy density of the electron beam injected per unit area per unit time remains unchanged, resulting in an increase in the amount of light emitted.
According to the experiments of this example, this method can improve
A brightness improvement of 0% was provided. As is clear from the above embodiments, the device of the present invention, in summary, is provided with a poppy light body corresponding to a large number of picture elements two-dimensionally, and excites the picture elements with a predetermined energy signal. A fluorescent display device for displaying an image, comprising a holding means for accumulating and holding an excitation signal for exciting each picture element for each predetermined time period, and a conversion means for converting the excitation signal into a high-speed scanning signal, Keeping the excitation energy density to the picture element constant,
This is a poppy light display device that is characterized by shortening the excitation time per cycle.This makes it possible to effectively utilize the light emission of the slow falling part of the light emitting characteristics of the poppy light body, and to maintain the same level as the conventional one. The excitation energy can significantly improve the brightness of the image display surface. Furthermore, according to the present invention, it is expected that the total amount of light emitted by the phosphor will increase, so it is possible to increase the resolution by controlling the density of the electron beam, and furthermore, even if the input is slightly reduced, it is possible to Considering that high brightness can be obtained, poppies are also useful for improving the efficiency of optical display devices.

Note that the device of the present invention is not limited to the solid color cathode ray tube described in each embodiment, but in general, the phosphor used for the picture element has a light emission time (emission fall time) that is longer than the rise time of excitation emission. ) can be applied to optical display devices, including monochrome poppies, optical cathode ray tubes, fluorescent plasma displays, etc.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the excitation energy of the poppy and light body according to the present invention and the corresponding changes in the luminescence characteristics over time, Fig. 2 is a block diagram of an embodiment of the present invention, and Fig. 3 is a diagram showing the corresponding changes in the emission characteristics over time. A specific circuit configuration diagram of one embodiment of the present invention, FIG. 4 is a main part circuit configuration block diagram of another embodiment of the present invention, FIGS. 5 and 6.
The figure is a diagram showing operating voltage waveforms of the main parts of the same embodiment. 1...Excitation pulse signal, 2...Emission characteristics, 3...Color cathode ray tube, 4...
Signal input terminal, 5...Shift register, 6...
...Buffer memory (holding means), 7...
Shift register (conversion means), 8... Wideband video amplifier, 9... Video signal input terminal, 13...
...Horizontal deflection coil, 40...Switching circuit, 41...Delay circuit, 42...Vertical deflection current. Figure 1 Figure 5 Figure 6 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1 Attach a phosphor that corresponds to a large number of pixels two-dimensionally,
In a fluorescent display device that displays an image by repeatedly scanning and exciting the picture elements for each column with a predetermined energy signal, an excitation signal for scanning and exciting each picture element is accumulated and held for a scanning period of each column of the picture elements. an accumulation/holding means, a conversion means for converting the excitation signal held by the accumulation/holding means into a high-speed scanning signal, and a sawtooth wave having a number of steps equal to the number of rows of picture elements in the slope part of the vertical scanning sawtooth wave. and a vertical scanning means for generating vertical scanning, in which the excitation energy density to each picture element is kept constant, and the excitation time per time of each picture element is scanned once for each row of the picture elements. A fluorescent display device that is characterized by its short size.