Active matrix substrate and active matrix display apparatus

• US 5,343,216 A
• Filed: 03/01/1993
• Issued: 08/30/1994
• Est. Priority Date: 01/31/1989
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Kato, Hiroaki, Katayama, Mikio, Kanemori, Yuzuru, Hirobe, Toshihiko, Nagayasu, Takayoshi, Negoto, Hidenori, Imaya, Akihiko
• Primary Examiner(s): Weldon, Ulysses
• Assistant Examiner(s): Luu, Matthew
• Application Number:
  US08/024,806
• Time in Patent Office: 547 Days
• Field of Search: 359/59, 359/87, 357/23.7, 357/45, 357/4, 357/51, 340/784, 345/87, 345/92, 345/93
• US Class Current: 345/92
• CPC Class Codes: G02F 1/1309 Repairing; Testing
• CPC Class Codes: G02F 1/133345 Insulating layers G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence
• CPC Class Codes: G02F 1/134345 Subdivided pixels, e.g. for grey scale or redundancy
• CPC Class Codes: G02F 1/13624 having more than one switching element per pixel
• CPC Class Codes: G02F 1/136268 Switch defects

Abstract

An active matrix substrate comprising picture element electrodes disposed in a matrix on a substrate, each of which is composed of divided electrodes, and an electrically conductive film on which two of said divided electrodes adjacent to each other are superposed in a manner to sandwich an insulating film therebetween so as to form a connection. The connection is irradiated with laser beams from the outside of the display apparatus when one of the divided electrodes brings about a picture element defect, so that both the divided electrodes can be electrically connected to each other, thereby attaining a correction of the picture element defect. A display apparatus using the active matrix substrate is also provided.

Claims

1. An active matrix substrate comprising:

transparent picture element electrodes disposed in a matrix on an insulating substrate, each of said picture element electrodes being composed of a plurality of divided electrodes;

a gate bus wiring and a source bus wiring intersecting with each other and being connected to each of said divided electrodes through a switching element; and

an electrically conductive film being of the same material as said gate bus wiring, on which a portion of each of two of said divided electrodes that are adjacent to each other is superposed, each of said portions of the two divided electrodes and said electrically conductive film being disposed in a nonconductive state with an insulating film sandwiched therebetween, resulting in a connection portion;

wherein a pair of metal pieces, respectively, are disposed between one of said portions of the two divided electrodes and said insulating film and between the other of said portions of the two divided electrodes and said insulating film at edge portions of said divided electrodes;

wherein a hole is formed for said insulating film in a portion thereof positioned between one of said pair of metal pieces and said electrically conductive film;

wherein said connection portion is covered with a protective coat so as to be confined between said protective coat and said insulating substrate; and

wherein one of said two divided electrodes detected as a defect is capable of being electrically connected with the other of said two divided electrodes by irradiating said edge portions of the divided electrodes with laser from outside of said insulating substrate.

2. An active matrix display apparatus comprising;

a first substrate which is translucent, and a second substrate;

a display medium which is charged between said first and second substrates, the optical characteristics of said display medium being modulated in response to an applied voltage;

transparent picture element electrodes disposed in a matrix on said first substrate, each of said picture element electrodes being composed of a plurality of divided electrodes;

an opposite electrode disposed on said second substrate;

a gate bus wiring and a source bus wiring intersecting with each othe and being connected to each of said divided electrodes through a switching element; and

an electrically conductive film on which a portion of each of two of said divided electrodes that are adjacent to each other is superposed, at least one of said portions of the tow divided electrodes and said electrically conductive film being disposed in a nonconductive state with an insulating film sandwiched therebetween, resulting in a connection portion;

wherein said connection portion is covered with a protective insulating coat so as to be isolated from said display medium; and

wherein one of said two divided electrodes detected as a defect is capable of being electrically connected with the other of said two divided electrodes by irradiating said connection portion with laser from outside of said first substrate.

3. A active matrix display apparatus according to claim 2, wherein a pair of metal pieces, respectively, are disposed between one of said portions of the two divided electrodes and said insulating film and between the other of said portions of the two divided electrodes and said insulating film .

4. An active matrix display appartus as set forth in claim 3, wherein a hole is disposed in a portion of said insulating film positioned between one of said pair of metal pieces and said electrically conductive film.

5. An active matrix display apparatus according to claim 2, wherein said electrically conductive film is electrically connected with one of said portions of the two divided electrodes.

6. An active matrix display apparatus according to claim 2, wherein each of said divided electrodes comprises an upper layer divided electrode and a lower divided electrode and said electrically conductive film is disposed so that it faces each of said upper layer divided electrodes so as to sandwich said insulating film therebetween in a non-conductive state, thereby constituting said connection portion.

7. An active matrix display apparatus according to claim 6, wherein a pair of metal pieces are disposed at said connection portion between said two upper layer divided electrodes and said insulating film.

8. An active matrix display apparatus according to claim 6, wherein said lower layer divided electrode of one of said two adjacent divided electrodes and said electrically conductive film are electrically connected with each other at said connection portion.

9. An active matrix display apparatus comprising:

a first substrate which is translucent, and a second substrate;

a display medium charged between said first and second substrates, the optical characteristics of said display medium being modulated in response to an applied voltage;

transparent picture element electrodes disposed in a matrix on said first substrate, each of said picture element electrodes being composed of a pair of divided electrodes;

an opposite electrode disposed on said second substrate;

a gate bus wiring disposed between said divided electrodes, and a source bus wiring intersecting with said gate bus wiring, said gate bus wiring and said source bus wiring being connected to each of said divided electrodes through a switching element; and

an electrically conductive film on which a portion of each of two of said divided electrodes is superposed, said two divided electrodes constituting two of said picture element electrodes that are adjacent to each other, said electrically conductive film being of the same material as said gate bus wiring;

wherein a pair of metal pieces are superposed on both ends of said electrically conductive film so as to sandwich an insulating film therebetween, in a non-conductive state, and said portions of the divided electrodes are superposed on said metal pieces in a conductive state respectively, resulting in a connection portion;

wherein said connection portion is covered with a protective insulating coat so as to be isolated from said display medium; and

wherein one of said two divided electrodes detected as a defect is capable of being electrically connected with the other of said two divided electrodes by irradiating said connection portion with laser from outside of said first substrate.

10. A method of correcting a picture element defect of an active matrix display apparatus, comprising the steps of:

assembling an active matrix display apparatus which comprises a first substrate which is translucent and a second substrate, a display medium which is charged between said first and second substrates, the optical characteristics of said display medium being modulated in response to an applied voltage, picture element electrodes disposed in a matrix on said first substrate, each of said picture element electrodes being composed of a plurality of divided electrodes, an opposite electrode disposed on the other of said substrates, a gate bus wiring and a source bus wiring intersecting with each other and being connected to each of said divided electrodes through a switching element, and an electrically conductive film on which a portion of each of two of said divided electrodes that are adjacent to each other is superposed, at least one of said portions of the two divided electrodes and said electrically conductive film being disposed in a non-conductive state with an insulating film sandwiched therebetween, resulting in a connection portion, wherein said connection portion is covered with a protective insulating coat so as to be isolated from said display medium;

putting the entire display picture plane of said active matrix display apparatus in a display state so as to detect a picture element defect which occurred in one of said two divided electrodes; and

irradiating said connection portion with laser from outside of said first substrate so as to electrically connect said divided electrode detected as a defect with the other of said two divided electrodes.

11. A correcting method according to claim 10, wherein a pair of metal pieces, respectively, are disposed between one of said portions of the two divided electrodes and said insulating film and between the other of said portions of the two divided electrodes and said insulating film.

12. A correcting method according to claim 11, wherein a hole is disposed in a portion of said insulating film positioned between one of said pair of metal pieces and said electrically conductive film.

13. A correcting method according to claim 10, wherein said electrically conductive film is electrically connected with one of said portions of the two divided electrodes.

14. A correcting method according to claim 10, wherein each of said divided electrodes comprises an upper layer divided electrode and a lower layer divided electrode and said electrically conductive film is disposed so that it faces each of said upper layer divided electrodes so as to sandwich said insulating film therebetween in a non-conductive state, thereby constituting said connection portion.

15. A correcting method according to claim 14, wherein a pair of metal pieces are disposed at said connection portion between said two upper layer divided electrodes and said insulating film.

16. A correcting method according to claim 14, wherein said lower layer divided electrode of one of said two adjacent divided electrodes and said electrically conductive film are electrically connected with each other at said connection portion.

17. A method of correcting a picture element defect of an active matrix display apparatus, comprising the steps of:

assembling an active matrix display apparatus which comprises a first substrate which is translucent, a display medium charged betwen said first and second substrates, the optical characteristics of said display medium being modulated in response to an applied voltage, transparent picture element electrodes disposed in a matrix on said first substrate, each of said picture element electrodes being composed of a pair of divided electrodes, an opposite electrode disposed on the other hand of said substrates, a gate bus wiring disposed between said divided electrodes, and a source bus wiring intersecting with said gate bus wiring, said gate bus wiring and said source bus wiring being connected to each of said divided electrodes through a switching element, and an electrically conductive film on which a portion of each of two of said divided electrodes is superposed, said two divided electrodes constituting two of said picture element electrodes that are adjacent to each other, said electrically conductive film being of the same material as said gate bus wiring, wherein a pair of metal pieces are superposed on both ends of said electrically conductive film so asto sandwich an insulating film therebetween, in a non-conductive state, and said portions of the divided electrodes are superposed on said metal pieces in a conductive state respectively, resulting in a connection portion, wherein said connection portion is covered with a protective insulating coat as to be isolated from display medium;

putting the entire display picture plane of said active matrix display apparatus in a display state so as to detect a picture element defect which occurred in one of said two divided electrodes; and

irradiating said connection portion with laser from outside of said first substrate so as to electrically connect said divided electrode detected as a defect with the other of said two divided electrodes.