JPH0749666A - Display unit - Google Patents

Abstract

PURPOSE:To improve reliability by providing a second shift register circuit provided with the same number of stages as a first shift register circuit and supplying the display data to an adjacent display unit of the poststage through the second shift register circuit. CONSTITUTION:A shift resister circuit 7 connected between a connector 41 and the connector 42 is the shift register circuit (a second shift register circuit) of serial-in/serial-out, and is constituted so as to become the same number of stages as a shift register circuit 5 for display. Since a parallel output signal is eliminated by the shift register circuit 7, the number of pieces of lead wires when the circuit is made into IC is reduced, and a failure hardly occurs. Further, since no latch/drive circuit is incorporated, a calorific value is reduced, and the reliability is enhanced. Then, this unit is constituted so as to make the serial output signal of the shift register circuit 7 the display data to the next display unit. Thus, the display data are sent to the display unit of the poststage without being affected by the failure of a displaying IC.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display unit in which a plurality of light emitting diodes are used as display elements and a plurality of them are arranged in a matrix in the vertical and horizontal directions to display characters or figures by dot-spacing.

[0002]

2. Description of the Related Art Conventionally, in consideration of manufacturability and maintainability, an information display device has a display portion of an information display device 1 composed of a plurality of display units 2 as shown in FIG. 2, a plurality of light emitting diodes 3 are arranged in a vertical and horizontal matrix as shown in FIG. FIG. 6 is a block diagram showing the configuration of the display unit 2. This display unit 2 is connected to an adjacent display unit by a connector 4 for connection.
When the display data (serial input signal) in serial format is input from the connector 41, the connection is made to the shift register circuit 5 (first shift register circuit). The shift register circuit 5 takes in display data in a serial format and outputs a serial output signal and a parallel output signal.

The serial output signal of the shift register circuit 5 is supplied to the shift register circuit 5 of the next stage, and the parallel output signal is supplied to the latch drive circuit 6 and held there, and is connected as a load to the light emitting diode. 3 is driven. The shift register circuit 5 and the latch drive circuit 6 reduce assembly man-hours to improve economic efficiency and reliability,
It is often the case that both circuits are integrated into an IC. Here, in FIG. 6, a shift clock for shifting a serial signal, a latch signal for storing data in the latch drive circuit 6, and the like are well known, and therefore description and description thereof are omitted.

[0004]

In FIG. 6, the shift register circuit 5 and the latch drive circuit 6 are normally one.
Since a data processing capacity of about 6 bits is required, the display unit 2 as a whole is required to have a capacity of transferring and storing data of about 256 bits, and the shift register circuit 5 and the latch drive circuit 6 each have 16 bits. You will need one by one. When the electronic circuit is composed of an IC, the failure rate becomes small, but the failure rate takes a certain value instead of zero.
Since many shift register circuits 5 and latch drive circuits 6 are used in the entire information display device, the failure rate of the device increases as the number of ICs used increases even if they are integrated into ICs. Further, if even one shift register circuit 5 fails, data cannot be supplied to the adjacent shift register circuit 5 in the subsequent stage, so that it is impossible to display the subsequent portions. Further, if one of the shift register circuits is destroyed due to lightning surge or the like, the display data supplied to the shift register circuit of the next stage becomes abnormal, and the display of the subsequent portions may become abnormal. Further, since this shift register circuit 5 is soldered to the printed circuit board, if there is a soldering failure even at one place, the display data is not transferred to the shift register circuit 5 of the next stage, and the subsequent parts can be displayed. Disappear. In addition, the shift register circuit 5 and the latch
Although the one in which the drive circuit 6 is integrated improves the economic efficiency, there is a problem that the failure rate increases because the heat generation increases. As described above, there is a problem that the display reliability of the entire device is deteriorated when the economical efficiency is improved by making the internal circuit into an IC. The present invention has been made in view of such a situation, and is intended to improve economic efficiency and not reduce reliability.

[0005]

In order to solve the above problems, the present invention uses a light emitting diode as a display element, and arranges a plurality of light emitting diodes in a matrix to form a unit including a drive circuit. The driving circuit includes a serial-in-parallel-out first shift register circuit that transfers display data, and a latch drive circuit that stores a parallel output signal of the first shift register circuit and drives a light-emitting diode. , A serial-in-serial-out second shift register circuit having the same number of stages as the first shift register circuit is provided, and display data is transferred to the next unit by using the serial output signal of the second shift register circuit. , The influence of the IC failure on the entire display is minimized.

[0006]

A shift for display is performed by shifting the display serial input signal by the second shift register circuit having the same number of stages as the first shift register circuit for display and supplying it as a serial output signal to the adjacent display unit. Even if the portion including the register circuit fails, the display of the display units other than the display unit is performed without any trouble.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing an embodiment of the present invention, and the same parts as in FIG. The shift register circuit 7 connected between the connector 41 and the connector 42 is a serial-in-serial-out shift register circuit (second shift register circuit), and has the same number of stages as the display shift register circuit 5. Has been done. Since this shift register circuit 7 does not need a parallel output signal, the number of lead wires when integrated into an IC is small, and a failure due to a defective soldering is unlikely to occur. Also, since it does not include a latch drive circuit, it generates less heat and is highly reliable. Further, since it can be formed at a high density with a small amount of power such as CMOS, it can be formed by one IC, and can be easily formed by a programmable gate array or the like.

Therefore, by configuring the serial output signal of the shift register circuit 7 to be the display data for the next display unit, the display unit is not affected by the failure of the display IC and is displayed on the display unit in the subsequent stage. Since data (serial output signal) can be sent, a highly reliable information display device can be provided. Although the shift register circuit 7 is provided so as to correspond to the display unit in this embodiment, the present invention is not limited to this, and the shift register circuit 7 may be provided for a plurality of display units.

FIG. 2 is a block diagram showing a second embodiment. The serial output signal of the shift register circuit 5 (first serial output signal) and the serial output signal of the shift register circuit 7 (second serial output signal) are shown. Signal) is supplied to the comparison circuit 8, and the comparison circuit 8 sends out the serial output signal output from the shift register circuit 7. When the command signal is supplied from the connector 10, the comparison circuit 8 compares the both input signals and, when they do not match, also outputs the mismatch detection signal. When the command signal is not supplied from the connector 10, the data inverting circuit 9 outputs the serial output signal output from the comparison circuit 8 as it is, but the command signal is supplied and the mismatch signal is output from the comparison circuit 8. The comparison circuit 8
The logic of the serial output signal output from is inverted and output.

The comparison circuit 8 and the data inversion circuit 9
Constitutes a signal processing circuit. In the device thus configured, when the command signal is supplied to the connector 10, the comparison circuit 8 compares the serial output signals supplied from the shift register circuits 5 and 7, and if they match, the shift register circuit. The serial output signal supplied from 7 is supplied to the data inverting circuit 9, and in the case of a mismatch, in addition to the signal, a mismatch detection signal is also supplied to the data inverting circuit 9. The data inversion circuit 9 is supplied with the same command signal as that of the comparison circuit 8 at the same timing, and when the non-coincidence signal is supplied from the comparison circuit 8, the serial output of the shift register circuit 7 supplied via the comparison circuit 8. The logic "1" and "0" of the signal are inverted and supplied to the connector 42. The command signal supplied to the connector 10 determines whether or not there is an abnormality in the display unit 2. As described above, if there is an abnormality in the display unit 2, the data is inverted and the display state is disturbed. , Not shown, latches when the command signal is supplied.
It is necessary to keep the data of the drive circuit 6 unchanged.

FIG. 3 is a block diagram of an information display device using the display unit shown in FIG. 2. When the control unit 11 receives a display command from the central unit 13 via the transmission line 12, the connector 41 of the display unit 2 receives it. Send and display the display data.
In addition, the control unit 11 sends a command signal to the connector 10 of the display unit 2 in response to a command from the central unit 13 or periodically, and takes in a serial output signal from the connector 42 of the display unit 2 at the final stage. Output the shift clock for. When the control unit 11 fetches the data for all the display units, it compares the fetched data with the display data output to the connector 41 of the display unit 2 first. If there is no abnormality in the display unit 2, no inconsistency is detected, but if any one of the display units 2 has an abnormality and the display unit 2 receives the command signal and the comparison circuit 8 detects an inconsistency, the data inversion circuit 9 causes Since the data inversion is performed, the control unit 11 can detect the display unit in which the data is inverted, that is, the abnormal display unit 2 by comparing with the display data.

The control unit 11 can inform the central unit 13 of the abnormality of the display unit 2 by seeing the transmission line 12.
This makes it possible to easily replace the abnormal display unit 2 and provide a device with good maintainability. In the above description, the control unit 11 compares the display data and the serial-out data of the display unit 2, but the serial-out data of the display unit 2 is sent to the central unit 13 via the transmission line 12, and the central unit 13 is sent. The central device 13 may detect the abnormality of the display unit 2 by comparing the display data with the display data.

[0013]

As described above, according to the present invention, the second shift register circuit having the same number of stages as the first shift register circuit for display is provided, and the display data are adjacent to each other via the second shift register circuit. It is designed to be supplied to the display unit in the subsequent stage. Therefore, the second shift register circuit does not require a circuit for display and the amount of heat generated is reduced, so that the reliability is improved and the reliability of the display data supplied to the subsequent stage is improved. Further, even if the display circuit is integrated into an IC to improve the economical efficiency and the reliability is lowered, the display failure occurs only in the defective display unit. In the other display units, the display failure occurs. Since the display can be performed normally, the influence of the failure of one display unit on the entire display becomes extremely small, and the reliability of the entire display device is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of another embodiment of the present invention.

FIG. 3 is a block diagram of a display device configured by using the device of FIG.

FIG. 4 is a diagram showing an entire display surface of a display device.

5 is a diagram showing a display surface of a display unit used in the device of FIG.

FIG. 6 is a block diagram showing an example of a conventional display unit.

[Explanation of symbols]

 1 Information Display Device 2 Display Unit 3 Light Emitting Diode 5, 7 Shift Register Circuit 6 Latch Drive Circuit 8 Comparison Circuit 9 Data Inversion Circuit 10 Connector 11 Controller 13 Central Unit 12 Transmission Line

 ─────────────────────────────────────────────────── ─── Continuation of front page (71) Applicant 390010054 Koito Industry Co., Ltd. 100, Maeda-cho, Totsuka-ku, Yokohama-shi, Kanagawa (72) Inventor Takehisa Seki 1-2-6 Hatchobori, Chuo-ku, Tokyo 72) Inventor Kotaro Nakajima 36 Shindaike, Terada, Joyo-shi, Kyoto Within Seiwa Electric Co., Ltd. Inside the factory (72) Inventor Kazuhisa Murata 492 Minosho-cho, Yamatokoriyama City, Nara Sharp Co., Ltd. (72) Inventor Mitsuru Sakai 100 Maeda-cho, Totsuka-ku, Yokohama-shi, Kanagawa Koito Industry Co., Ltd.

Claims (2)

[Claims] 1. A parallel output signal generated by shifting a serial input signal by a first shift register circuit to arbitrarily control display states of a plurality of light emitting diodes and to output a serial output signal of the same format as the serial input signal. And a second shift register circuit which has the same number of stages as the first shift register circuit and which outputs a serial input signal as a serial output signal having the same format as the first shift register circuit. unit. 2. The contents of both signals according to claim 1, wherein a first serial output signal output from the first shift register circuit and a second serial output signal output from the second shift register circuit are supplied. A signal that outputs the second serial output signal when the two signals do not match and a command signal is supplied from the outside when a logic signal of the second serial output signal is inverted. A display unit comprising a processing circuit.