JPH0478897A - Luminance signal transfer system - Google Patents

Abstract

PURPOSE:To decrease the number of signals transferred to a display device and to reduce electric conductors required for the signal transfer by imposing pulse-width modulation upon a load signal according to a luminance signal and transferring this signal as a signal which serves as both the load signal and luminance signal. CONSTITUTION:On a controller side, the signal generated by imposing pulse- width modulation upon the load signal with the luminance signal is sent out as the signal which serves as both the load signal and luminance signal and on a display side, the latching of display data and a turn-off period are controlled according to the load/luminance signal to make a display with brightness gradations. Therefore, only three signal lines which are a signal line for sending at least the display data, a signal line for sending a clock signal, and a signal line for sending the load/brightness signal between the controller and individual CRTs, so the number of signal lines is decreased to greatly decrease the electric conductors required for the whole display device.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a signal transfer method for display control of a display element, and more specifically to a luminance signal transfer method, by reducing the number of signals transferred to a display device and reducing the number of signals necessary for signal transfer. In order to reduce the number of wiring lines, the display device includes display data that specifies whether to turn on or off the display element, a clock signal that serves as a reference for data transfer, a load signal that specifies the latch timing of the display data, and a load signal that specifies the latch timing of the display element. In a signal transfer method for transmitting a luminance signal specifying a luminance gradation of a luminance signal to a display device, the load signal is pulse width modulated by the luminance signal, and this modulated signal is used as a signal that serves as both the load signal and the luminance signal. Configure to forward as .

[Industrial application field]

The present invention relates to a signal transfer method for display control of a display element, and more particularly to a luminance signal transfer method.

[Conventional technology]

A display device that displays characters, pictures, etc. by arranging a large number of display elements (including lamps, CRT tubes, etc., and peripheral circuits that drive the display elements) in a matrix pattern and controlling the blinking of these display elements. are known, and these display devices are used for advertisements and the like.

-C, in this type of display device, the display elements that display characters, pictures, etc., and the control device that controls the blinking of these display elements are placed separately, and the two are connected by cables, etc. There is.

In such a display device, for example, when displaying with gradations, at least a display signal that instructs the display elements to blink, a clock signal that serves as a reference for data transfer, and a latch timing of display data are determined. It is necessary to transfer a load signal and a luminance signal specifying the luminance gradation of the display element from the control device to the display element.

FIG. 4 is a diagram showing an example of a signal waveform transferred from a control device to a display element in a conventional signal transfer method.

First, display data and a clock signal are sequentially output from the control device. Thereafter, a load signal is output, and the display data transferred on the display element side is latched in synchronization with this load signal.

Further, at this time, as a luminance signal that specifies the luminance gradation of the display element, for example, a signal that specifies the lighting time or extinguishing time of the display element is output.

For example, by changing the on-width and off-width of the luminance signal by lighting the display element during the period when the luminance signal is at a high level and turning off the display element during the period when the luminance signal is at a low level, as shown in FIG. The brightness gradation of the element can be controlled.

[Problem to be solved by the invention]

By the way, there is a demand for display devices used for displaying advertisements and the like to display a variety of information in an easier-to-see manner, and the display screens tend to become larger. Along with this, the number of display elements used in one display device has also increased, posing the problem that the wiring between the control device and the display elements has become increasingly complicated.

An object of the present invention is to reduce the number of signals transferred to a display device,
The goal is to reduce the amount of wiring required for signal transfer.

[Means to solve the problem]

The present invention includes display data that specifies the display state of the display element, a clock signal that serves as a reference for data transfer, a load signal that specifies the launch timing of the display data, and a luminance that specifies the luminance gradation of the display element. In a signal transfer method for transferring a signal to a display device, the load signal is pulse width modulated based on a luminance signal, and this modulated signal is transferred as a signal that serves as both a load signal and a luminance signal.

[For production]

Based on the above-described signal transfer method, the control device side may pulse-width-modulate the load signal based on the luminance signal and send it to the display element as a signal that serves as both the load signal and the luminance signal.

Then, on the display element side, for example, the display data is latched in synchronization with the rise of the signal, and the display is performed with a brightness corresponding to the pulse width of the signal, thereby latching the display data and displaying with gradation. You can do both. In other words, display data can be latched and gradation display can be performed together with one signal.

Therefore, it is only necessary to transfer at least three types of signals or data from the control device to the display element: a signal that also serves as a load signal and a luminance signal, a clock signal, and display data. The number of wires connected to the device can be reduced, and the wires between the two can be greatly simplified.

〔Example〕

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

FIG. 1 is a diagram showing an example of a signal waveform according to the luminance signal transfer method of the present invention.

From the control device (not shown) side, as shown in Figure 1,
Display data that instructs each display element (such as a CRT) to turn on or off is sent out in synchronization with a clock signal.

Then, the load signal that specifies the launch timing of display data is pulse width modulated by the luminance signal that specifies the luminance gradation, and is sent out as a load/luminance signal that serves as both signals.

On the receiving side, first, display data is sequentially shifted in synchronization with the above-mentioned clock signal, and these display data are held.

Furthermore, the display data can be launched in synchronization with the rise of the load/luminance signal, and the luminance gradation of the display element can be controlled based on the pulse width of the load/luminance signal.

Next, FIG. 2 is a diagram schematically showing a cross section of the display section to which the above-mentioned signals and data are transferred.

This display section consists of a large number of CRTs arranged in a matrix.
Each CRTI is a CRT installed in panel 2.
It is arranged to be removably attached to the socket 3.

The CRT socket 3 is connected by a cord to a branch printed board 4, and the branch printed board 4 is further connected by a cord to a control device that outputs the above-mentioned display data and signals related to the display.

Next, FIG. 3 is a circuit diagram of a display driver circuit provided on the branch printed board 4. As shown in FIG.

The display data and signal sent from the control unit are as follows:
The signals are input to the D input terminal and clock terminal of the shift register 5 through the buffer 7, respectively.

Further, the load/luminance signal is input to the latch circuit 6 via the buffer 7.

The shift register 5 is, for example, a circuit in which a plurality of D flip-flops are connected in series, and the display data inputted from the D input terminal is sequentially shifted to the next flip-flop in synchronization with a clock signal, and the data is transferred to the next flip-flop. hold.

The latch circuit 6 is composed of registers corresponding to the number of outputs of the shift register 5, and latches the data output from the shift register 5 in synchronization with the rising edge of the load/luminance signal, and performs an AND operation on the data output from the shift register 5. Gate group 8
Output to.

The AND gate group 8 includes a number of AND gates corresponding to the number of outputs of the latch circuit 6, and the output of each AND gate is connected to the grid G of the CRTI via a buffer 9.

The input terminal of this AND gate group 8 is connected to the output signal of the latch circuit 6 and the load/luminance signal to the inverter 10.
The inverted signal is input, and the ANDed signal of both signals is output to the buffer 9.

Next, we will explain the operation of the display drive circuit configured as above in the first step.
This will be explained with reference to FIG. 3 and FIG.

During a period until the load/brightness signal is sent out (a period in which the load/brightness signal is inactive), display data sent from the control device is sequentially taken into the shift register 5 in synchronization with the clock.

Also, the load/brightness signal is inactive (low level).
During the period, the inverted load/ff degree signal becomes active (high level), the AND gate group 8 opens, and the display data latched in the launch circuit 6 at that time is output to the buffer 9.

As a result, a drive signal corresponding to the display data is given to Glycid G of the CRTI, and if the display data is "1", the CRTI is turned on, and if the display data is "0", the CRTI is turned off. Become.

On the other hand, when the load/luminance signal switches from inactive to active, the display data held in the shift register 5 at that time is latched into the latch circuit 6 in synchronization with the rising edge of the load/luminance signal.

Further, while the load/luminance signal is active, its inverted signal is inactive, so the AND gate group 8 is closed.

As a result, the display data held in the latch circuit 6 at that time is not output to the buffer 9, and the output of the buffer 9 becomes low level.

Therefore, while the load/brightness signal is at low level, the CRT
The grid G of I becomes low level, and the CRTl goes out.

In this way, the display data is the data that instructs lighting ('I
J) and while the load/luminance signal is inactive,
The CRT 1 is turned on, and the CRTI is turned off while the load/ff degree signal is active.

That is, by changing the inactive period of the load/luminance signal, that is, its on width, the ratio of the CRTI lighting period to the lighting period is changed, and each CRTI
The brightness gradation can be controlled.

As described above, on the control device side, a signal obtained by pulse width modulating the load signal with a luminance signal is sent out as a signal that serves as both a load signal and a luminance signal, and on the display side, the load/luminance signal is
By controlling display data latching and extinguishing period based on the luminance signal, display with luminance gradation can be performed.

Therefore, it is only necessary to have at least three signal lines between the control device and each CRTI: a signal line for sending display data, a signal line for sending clock signals, and a signal line for sending load/luminance signals. Therefore, the number of signal lines can be reduced and the number of wirings required for the entire display device can be significantly reduced.

Note that in the above embodiment, CR is determined based on the load/luminance signal.
Although the case where the lighting period and the lighting period of the CRT are changed has been described, for example, the grid voltage may be controlled based on the load/brightness signal to control the brightness when the CRT is turned on and change the gradation.

[Effects of the Invention] According to the present invention, the number of signals sent to the display element is reduced,
The number of wiring lines required for signal transfer can be significantly reduced.

[Brief Description of the Drawings] Fig. 1 is a diagram showing an example of a signal waveform according to the luminance signal transfer method of the present invention, Fig. 2 is a schematic vertical cross-sectional view of a display device according to an embodiment, and Fig. 3 is a display FIG. 4, a circuit configuration diagram of the drive circuit, is a diagram showing an example of a signal waveform according to a conventional signal transfer method. 2 bars 1 ・ ・ ・ CRT, 5...Shift register, 6...Latch circuit. Award 1 color Iboku front small thorn holder model Rokujin” Front view Figure 2 Patent applicant: Fujitsu Kiden Ltd.

Claims (1)

[Claims] Display data that specifies whether to turn on or off a display element; a clock signal that serves as a reference for data transfer; a load signal that specifies latch timing of the display data; and a luminance gradation of the display element. In a signal transfer method for transferring a specified luminance signal to a display device, the load signal is pulse width modulated by the luminance signal, and this modulated signal is transferred as a signal that serves as both the load signal and the luminance signal. Features a luminance signal transfer method.