METHOD FOR TESTING LIQUID CRYSTAL DISPLAY DEVICE AND LIQUID CRYSTAL DISPLAY DEVICE

• US 20110175800A1
• Filed: 05/27/2009
• Published: 07/21/2011
• Est. Priority Date: 08/06/2008
• Status: Abandoned Application

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Mizumaki, Hidetaka
• Application Number:
  US13/057,189
• Publication Number:
  US 20110175800A1
• Time in Patent Office: Days
• US Class Current: 345/87
• CPC Class Codes: G01R 31/2812 Checking for open circuits or shorts, e.g. solder bridges; Testing conductivity, resistivity or impedance of connections G01R31/66
• CPC Class Codes: G02F 1/136254 Checking; Testing
• CPC Class Codes: G09G 2300/0408 Integration of the drivers onto the display substrate
• CPC Class Codes: G09G 2300/0417 Special arrangements specific to the use of low carrier mobility technology
• CPC Class Codes: G09G 2330/12 Test circuits or failure detection circuits included in a display system, as permanent part thereof
• CPC Class Codes: 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
• CPC Class Codes: G09G 3/3666 with the matrix divided into sections
• CPC Class Codes: H05K 1/0268 for electrical inspection or testing
• CPC Class Codes: H05K 2201/09781 Dummy conductors, i.e. not used for normal transport of current; Dummy electrodes of components
• CPC Class Codes: H05K 3/361 Assembling flexible printed circuits with other printed circuits

Abstract

An FPC (2) includes: wiring lines (8a) and (8b) which extend toward a display panel (1); and terminals (T1) and (T2) which are connected to the wiring lines (8a) and (8b), respectively. The display panel (1) includes a short-circuit wiring line (5) for short-circuiting the wiring lines (8a) and (8b). The EPC (2) and the display panel (1) are connected to each other so that the wiring lines (8a) and (8b) are short-circuited via the short-circuit wiring line (5) in a connection part between the FPC (2) and the display panel (1). A liquid crystal display device (30) includes a signal application circuit (31) for applying a signal to the terminal (T1) and a monitoring circuit (32) for comparing the signal applied to the terminal (T1) with a signal outputted from the terminal (T2). This provides a method of testing a liquid crystal display device and a liquid crystal display device each of which can check a connection condition between a display panel and a wiring board, such as a flexible circuit board (such as a COF and an FPC), not only while the liquid crystal display device is manufactured but also while the liquid crystal display device is in use.

Claims

1. A method for testing a liquid crystal display device,

the liquid crystal display device including:

a wiring board including (i) a signal supply line via which a signal for driving a display panel is supplied (ii) a first wiring line and a second wiring line which extend toward the display panel and (iii) a first terminal and a second terminal which are connected to the first wiring line and the second wiring line, respectively; and

a display panel including a first short-circuit wiring line via which the first wiring line and the second wiring line are to be short-circuited in a connection part between the wiring board and the display panel,

said method comprising the steps of;

(a) causing the wiring board and the display panel to be connected to each other;

(b) applying a signal to the first terminal; and

(c) comparing the signal applied to the first terminal with a signal outputted from the second terminal.

2. The method as set forth in claim 1, wherein:

in the step (a), the wiring board and the display panel are connected to each other via an intermediate substrate, which includes (i) a wiring line via which a signal is communicated between the display panel and the wiring board and (ii) a third wiring line and a fourth wiring line, so that (1) the first wiring line and the first short-circuit wiring line are electrically connected via the third wiring line and (2) the second wiring line and the first short-circuit wiring line are electrically connected via the fourth wiring line.

3. The method as set forth in claim 2, wherein:

the wiring board further includes (i) a fifth wiring line and a sixth wiring line and (ii) a third terminal and a fourth terminal which are connected to the fifth wiring line and the sixth wiring line, respectively;

the intermediate substrate further includes a second short-circuit wiring line via which the fifth wiring line and the sixth wiring line are to be short-circuited in a connection part between the wiring board and the intermediate substrate; and

said method further comprising the steps of;

causing the wiring board and the intermediate substrate to be connected to each other;

applying a signal to the third terminal; and

comparing the signal applied to the third terminal with a signal outputted from the fourth terminal.

4. The method as set forth in claim 1, wherein:

the signal applied to the first terminal is a pulse signal.

5. The method as set forth in claim 1, wherein:

the signal applied to the first terminal is a DC signal.

6. A liquid crystal display device comprising:

a wiring board including (i) a signal supply line via which a signal for driving a display panel is supplied (ii) a first wiring line and a second wiring line which extend toward the display panel and (iii) a first terminal and a second terminal which are connected to the first wiring line and the second wiring line, respectively; and

a display panel including a first short-circuit wiring line via which the first wiring line and the second wiring line are to be short-circuited in a connection part between the wiring board and the display panel,

the wiring board and the display panel being connected to each other,

said liquid crystal display device further comprising;

signal application means for applying a signal to the first terminal; and

comparison means for comparing the signal applied to the first terminal with a signal outputted from the second terminal.

7. The liquid crystal display device as set forth in claim 6, wherein:

the first wiring line and the second wiring line are provided in at least one of lateral end parts of the wiring board.

8. The liquid crystal display device as set forth in claim 6, wherein:

the wiring board and the display panel are connected to each other via an intermediate substrate, which includes (i) a wiring line via which a signal is communicated between the display panel and the wiring board and (ii) a third wiring line and a fourth wiring line, so that (1) the first wiring line and the first short-circuit wiring line are electrically connected via the third wiring line and (2) the second wiring line and the first short-circuit wiring line are electrically connected via the fourth wiring line.

9. The liquid crystal display device as set forth in claim 8, wherein:

the wiring board further includes (i) a fifth wiring line and a sixth wiring line and (ii) a third terminal and a fourth terminal which are connected to the fifth wiring line and the sixth wiring line, respectively;

the intermediate substrate further includes a second short-circuit wiring line via which the fifth wiring line and the sixth wiring line are to be short-circuited in a connection part between the wiring board and the intermediate substrate;

the signal application means applies a signal to the third terminal; and

the comparison means compares the signal applied to the third terminal with a signal outputted from the fourth terminal.

10. The liquid crystal display device as set forth in claim 8, wherein:

the intermediate substrate is made up of a plurality of intermediate substrates; and

the wiring board and the display panel are connected to each other via the plurality of intermediate substrates.

11. The liquid crystal display device as set forth in claim 9, wherein:

each of the plurality of intermediate substrates includes the fifth wiring line and the sixth wiring line in each of its lateral end parts.

12. The liquid crystal display device as set forth in claim 8, wherein:

the wiring board is a printed wiring board; and

the intermediate substrate is a wiring board in which an integrated circuit for driving the display panel is provided on a film.