Browse Prior Art Database

Redundancy for TFT/LCD

IP.com Disclosure Number: IPCOM000036988D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 72K

Publishing Venue

IBM

Related People

Suzuki, H: AUTHOR [+2]

Abstract

A new redundancy method for TFT/LCD is described which enables a high process yield. One of the most serious yield detractors of a TFT/LCD is the signal line's open defect. Because of its conspicuousness, one line defect makes the LCD valueless. According to the new method, a redundant signal line upon the upper glass of the LCD provides the automatic repair of the defective signal line (Fig. 1).

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Redundancy for TFT/LCD

A new redundancy method for TFT/LCD is described which enables a high process yield. One of the most serious yield detractors of a TFT/LCD is the signal line's open defect. Because of its conspicuousness, one line defect makes the LCD valueless. According to the new method, a redundant signal line upon the upper glass of the LCD provides the automatic repair of the defective signal line (Fig. 1).

A TFT/LCD structure in common use today has no redundant circuit. Therefore, to repair the defected signal line requires an additional time- consuming operation, such as wire bonding and soldering. This operation also degrades the LCD's reliability itself.

(Image Omitted)

The new arrangement for the TFT/LCD disclosed herein is as follows:

(1) The LCD has redundant signal lines on the upper

glass of the cell (opposite the TFT fabricated

glass) (Fig. 2).

(2) Redundant signal lines are fabricated on the same

area of the Black Matrix. Therefore, the

redundant signal lines do not degrade the

transparency of the LCD (Fig. 2).

(3) Connections between the redundant signal lines and

the TFT driving signal lines are achieved by

conducting spacer particles mixed with sealing

material (Fig. 3).

This structure provides automatic repair of defective signal lines within the TFT/LCD and enables achievement of high yield without any additional operation.

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