Laser repairing method of electroluminescent display device

• US 7,611,745 B2
• Filed: 01/16/2004
• Issued: 11/03/2009
• Est. Priority Date: 01/21/2003
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Nagata, Ryozo, Ogawa, Takashi, Nishikawa, Ryuji
• Primary Examiner(s): Meeks; Timothy H
• Assistant Examiner(s): LIN, JAMES
• Application Number:
  US10/758,598
• Publication Number:
  US 20040202777A1
• Time in Patent Office: 2,118 Days
• Field of Search: 427/66, 427/140, 427554-556, 445/3, 445/2
• US Class Current: 427/66
• 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: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/861 Repairing

Abstract

The invention is directed to repairing of a defective portion caused by a short circuit without generating a dark spot by a pin hole. Laser beams are irradiated to an irradiating region set in a peripheral region of a foreign substance. This prevents damaging of an organic EL element which the foreign substance adheres to and formation of the pin hole. By irradiating laser beams to the peripheral region at a distance from the foreign substance, energy of the laser beams spreads concentrically around the irradiating region, and is also supplied to the foreign substance indirectly. Therefore, the high resistive region can be formed between an anode layer and a cathode layer so that the defective portion caused by the short circuit by the foreign substance can be repaired.

Claims

1. A method of repairing an electroluminescent display panel using laser, comprising:

providing a panel to be assembled into an electroluminescent display device, the panel comprising a plurality of pixels each including an electroluminescent element having an electroluminescent layer formed between an anode layer and a cathode layer;

detecting a foreign substance adhering to the electroluminescent element; and

irradiating with a laser beam a region of the display panel that is away from the foreign substance so that a high resistivity region is formed as a result of a melting by the laser beam of the electroluminescent layer between the anode layer and the cathode layer and around the foreign substance,

wherein the laser beam is not directly incident on the detected foreign substance but the energy that spreads concentrically from the laser beam is irradiated on the foreign substance such that the laser energy is supplied to the foreign substance indirectly,

the electroluminescent layer comprises a layered structure of a hole transport layer, an emissive layer and an electron transport layer, and during the melting of the electroluminescent layer the hole transport layer, the emissive layer and the electron transport layer are melted together so that the layered structure disappears and the high resistivity region comprising melted constituents of the hole transport layer, the emissive layer and the electron transport layer is formed between the anode layer and the cathode layer, and

at the portion of the electroluminescent element on which the laser beam is incident, the anode layer and the cathode do not lose a layer structure thereof and remain on and below the melted constituents.

2. The method of claim 1, wherein the laser beam irradiation is repeated a plurality of times so that a plurality regions of the display panel around the foreign substance is irradiated.

3. The method of claim 2, wherein a wavelength of the laser beam is 532 nm or lower.

4. The method of claim 2, wherein the irradiated region of the display panel is away from the foreign substance by a distance between 5 μ

m and 10 μ

m.

5. The method of claim 1, wherein a wavelength of the laser beam is 532 nm or lower.

6. The method of claim 1, wherein the irradiated region of the display panel is away from the foreign substance by a distance between 5 μ

m and 10 μ

m.

7. The method of claim 1, wherein the irradiation with the laser beam is performed so that the high resistivity region is in contact with an entire lateral edge of the foreign substance.