# US 2020/0400993 A1 · Liquid crystal display device

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- Number: US 2020/0400993 A1
- Document ID: US20200400993A1
- Status: Published application
- Kind: A1
- Application number: 16/904,599
- Filed: 2020-06-18
- Published: 2020-12-24
- Earliest claimed: 2019-06-20
- Assignees: Japan Display Inc.
- Applicants: Japan Display Inc.
- Inventors: Takafumi FUJITA; Seiji FURUMOTO
- Web page: https://patentgrep.com/patent/US20200400993A1

## CPC

- G02F 1/13452: {Conductors connecting driver circuitry and terminals of panels}
- G09G 3/2092: {Details of a display terminals using a flat panel, the details relating to the control arrangement of the display terminal and to the interfaces thereto (suitable for both CRT and flat panel G09G5/003; specific for a CRT G09G1/165)}
- G09G 3/006: {Electronic inspection or testing of displays and display drivers, e.g. of LED or LCD displays (testing individual LED's G01R31/2635; testing lamps G01R31/44; testing of optical features of LCD displays G02F1/1309)}
- G09G 3/3648: {using an active matrix (G09G3/367 - G09G3/3696 take precedence)}
- G09G 3/3674: {Details of drivers for scan electrodes}
- G09G 3/3685: {Details of drivers for data electrodes}
- G09G 2300/0426: Layout of electrodes and connections
- G09G 2300/0857: Static memory circuit, e.g. flip-flop
- G09G 2310/06: Details of flat display driving waveforms
- G09G 2330/021: Power management, e.g. power saving
- G09G 2330/12: Test circuits or failure detection circuits included in a display system, as permanent part thereof
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00)

## Abstract

According to one embodiment, a relay substrate provided between a liquid crystal panel and a controller includes first connectors. The controller includes a microcomputer and second connectors. The relay substrate and the controller include a line pattern to form a test circuit which feeds a test signal back to an input pin of the microcomputer from an output pin of the microcomputer, and which transfers the test signal between the controller and the relay substrate in each pair of the first connectors and the second connectors. The microcomputer outputs the test signal from the output pin, and determines a connecting state of the cables that connect the relay substrate and the controller based on a state of feedback of the test signal to the input pin.

## Claims

### Claim 1

A liquid crystal display device comprising:
a liquid crystal panel;
a controller configured to control the liquid crystal panel; and
a relay substrate provided between the liquid crystal panel and the controller, wherein:
the relay substrate and the controller are connected by a plurality of cables;
the relay substrate comprises a plurality of first connectors to which one end of the cables is connected;
the controller comprises:
a microcomputer; and
a plurality of second connectors which are paired with the first connectors and to which the other end of each of the cables is connected;
the relay substrate and the controller comprise a line pattern to form a test circuit which feeds a test signal back to an input pin of the microcomputer from an output pin of the microcomputer, and which transfers the test signal from the controller to the relay substrate and returns the test signal from the relay substrate to the controller in each pair of the first connectors and the second connectors; and
the microcomputer is configured to output the test signal from the output pin, and to determine a connecting state of the cables that connect the relay substrate and the controller based on a state of feedback of the test signal to the input pin.

### Claim 2 (depends on 1)

The liquid crystal display of claim 1, wherein:
the plurality of cables are flat flexible cables;
the plurality of first connectors and the plurality of second connectors are flat flexible cable connectors; and
the line pattern forms the test circuit such that the test signal is transferred from the controller to the relay substrate and returned from the relay substrate to the controller, using first and last ones of signal lines arranged in line in the cables that are flat flexible cables, in each pair of the first connectors and the second connectors.

### Claim 3 (depends on 2)

The liquid crystal display of claim 2, wherein the microcomputer is configured to output an optional pulse waveform from the output pin as the test signal, and to determine a connecting state of the cables according to whether or not the optional pulse waveform is fed back to the input pin with a specific timing.

### Claim 4 (depends on 3)

The liquid crystal display of claim 3, wherein the microcomputer is configured to repeat, a predetermined number of times, outputting the optional pulse waveform from the output pin and determining whether or not the optional pulse waveform is fed back to the input pin with a specific timing, and to determine that the cables are normally connected when it is confirmed that the optional pulse waveform is fed back to the input pin with the specific timing in all of the determinations repeated a predetermined number of times.

### Claim 5 (depends on 4)

The liquid crystal display of claim 4, further comprising a light emitting diode (LED),
wherein the LED is turned on to report a connection failure of the cables.

### Claim 6 (depends on 3)

The liquid crystal display of claim 3, further comprising a light emitting diode (LED),
wherein the LED is turned on to report a connection failure of the cables.

### Claim 7 (depends on 2)

The liquid crystal display of claim 2, further comprising a light emitting diode (LED),
wherein the LED is turned on to report a connection failure of the cables.

### Claim 8 (depends on 1)

The liquid crystal display of claim 1, wherein the microcomputer is configured to output an optional pulse waveform from the output pin as the test signal, and to determine a connecting state of the cables according to whether or not the optional pulse waveform is fed back to the input pin with a specific timing.

### Claim 9 (depends on 8)

The liquid crystal display of claim 8, wherein the microcomputer is configured to repeat, a predetermined number of times, outputting the optional pulse waveform from the output pin and determining whether or not the optional pulse waveform is fed back to the input pin with a specific timing, and to determine that the cables are normally connected when it is confirmed that the optional pulse waveform is fed back to the input pin with the specific timing in all of the determinations repeated a predetermined number of times.

### Claim 10 (depends on 9)

The liquid crystal display of claim 9, further comprising a light emitting diode (LED),
wherein the LED is turned on to report a connection failure of the cables.

### Claim 11 (depends on 8)

The liquid crystal display of claim 8, further comprising a light emitting diode (LED),
wherein the LED is turned on to report a connection failure of the cables.

### Claim 12 (depends on 1)

The liquid crystal display of claim 1, further comprising a light emitting diode (LED),
wherein the LED is turned on to report a connection failure of the cables.

### Claim 13

A liquid crystal display device comprising:
a first substrate; and
a second substrate, wherein:
the first substrate comprises a plurality of first connectors to which one end of each of a plurality cables is connected;
the second substrate comprises:
a microcomputer; and
a plurality of second connectors which are paired with the first connectors and to which the other end of each of the cables is connected;
the first substrate and the second substrate comprise a line pattern to form a test circuit which feeds a test signal back to an input pin of the microcomputer from an output pin of the microcomputer, and which transfers the test signal from the second substrate to the first substrate and returns the test signal from the first substrate to the second substrate in each pair of the first connectors and the second connectors; and
the microcomputer is configured to output the test signal from the output pin, and to determine a connecting state of the cables that connect the first substrate and the second substrate based on a state of feedback of the test signal to the input pin.