Flexible Printed Circuit Board and Liquid Crystal Display Device Using the Same

• US 20090040415A1
• Filed: 07/03/2008
• Published: 02/12/2009
• Est. Priority Date: 07/05/2007
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Wal-Hee
• Granted Patent: US 7,929,100 B2
• Time in Patent Office: Days
• US Class Current: 349/56
• CPC Class Codes: G02F 1/133612 Electrical details
• CPC Class Codes: G02F 1/13452 Conductors connecting driver circuitry and terminals of panels
• CPC Class Codes: H05K 1/147 at least one of the printed circuits being bent or folded, e.g. by using a flexible printed circuit H05K1/148 takes precedence
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/058 Direct connection between two or more FPCs or between flexible parts of rigid PCBs
• CPC Class Codes: H05K 2201/10106 Light emitting diode [LED]
• CPC Class Codes: H05K 2203/0455 PTH for surface mount device [SMD], e.g. wherein solder flows through the PTH during mounting
• CPC Class Codes: H05K 3/281 by means of a preformed insulating foil H05K3/284 takes precedence
• CPC Class Codes: H05K 3/363 by soldering

Abstract

A flexible printed circuit board for use in a liquid crystal display device includes: a body section having a light source portion embedded therein; a leg section including a solder pad connected to an external printed circuit board, the leg section being extended from the body section and integrally formed with the body section; and a single conductive layer formed across the body section and the leg section for electrically interconnecting the light source portion and the solder pad.

Claims

1. A flexible printed circuit board comprising:

a body section having a light source portion embedded therein;

a leg section including a solder pad connected to an external printed circuit board, the leg section being extended from the body section and integrally formed with the body section; and

a single conductive layer formed across the body section and the leg section for electrically interconnecting the light source portion and the solder pad.

2. The flexible printed circuit board according to claim 1, wherein the body section further comprises a first cover layer and a second cover layer, and the single conductive layer is formed between the first cover layer and the second cover layer.

3. The flexible printed circuit board according to claim 2, wherein a region where the solder pad of the leg section is formed further includes the first cover layer, and the single conductive layer is formed between the first cover layer and the solder pad.

4. A liquid crystal display device comprising:

a first circuit board having first and second conductive layers formed therein and a first solder pad formed therein to be electrically connected to the first conductive layer; and

a second circuit board having a second solder pad formed therein to be soldered to the first solder pad and a third conductive layer formed therein to be electrically connected to the second solder pad.

5. The liquid crystal display device according to claim 4, wherein the first solder pad of the first circuit board has via holes formed therein.

6. The liquid crystal display device according to claim 5, wherein the first circuit board has a power supply unit embedded therein and positioned at one side of a region thereof where the first solder pad is formed, the power supply unit being electrically connected to the first conductive layer.

7. The liquid crystal display device according to claim 6, wherein the second circuit board has a light source portion embedded therein electrically connected to the third conductive layer.

8. The liquid crystal display device according to claim 7, wherein the light source portion comprises a light emitting diode (LED).

9. The liquid crystal display device according to claim 8, wherein the first and second solder pads are soldered to each other through the filling of a solder into the via holes in close contact with each other.

10. The liquid crystal display device according to claim 9, wherein the first and second circuit boards are flexible printed circuit boards.

11. The liquid crystal display device according to claim 9, wherein the first circuit board is a printed circuit board.

12. The liquid crystal display device according to claim 10, wherein the second circuit board further comprises:

a body section having the light source portion embedded therein; and

a leg section having the second solder pad formed therein, the leg section being extended from the body section and integrally formed with the body section, and wherein the third conductive layer is formed across the body section and the leg section for electrically interconnecting the light source portion and the second solder pad.

13. The liquid crystal display device according to claim 12, wherein the body section further comprises a first cover layer and a second cover layer, and the third conductive layer is formed between the first cover layer and the second cover layer.

14. The liquid crystal display device according to claim 13, wherein a region where the second solder pad of the leg section is formed further includes the first cover layer, and the third conductive layer is formed between the first cover layer and the second solder pad.

15. The liquid crystal display device according to claim 14, wherein the third conductive layer comprises copper.

16. The liquid crystal display device according to claim 15, wherein the second solder pad comprises nickel or gold.

17. A method of fabricating a liquid crystal display device, comprising:

providing a first circuit board having first and second conductive layers formed therein and a first solder pad formed therein electrically connected to the first conductive layer, the first solder pad having via holes formed therein;

providing a second circuit board having a second solder pad formed therein to be soldered to the first solder pad and a third conductive layer formed therein electrically connected to the second solder pad;

allowing the second solder pad of the second circuit board to be in close contact with the first solder pad having the via holes formed therein; and

soldering the first soldering pad and the second soldering pad to each other through the filling of a solder into the via holes from the first circuit board side.

18. The method according to claim 17, wherein the first circuit board has a power supply unit embedded therein positioned at one side of a region thereof where the first solder pad is formed, the power supply unit being electrically connected to the first conductive layer.

19. The method according to claim 18, wherein the second circuit board has a light source portion embedded therein electrically connected to the third conductive layer.

20. The method according to claim 19, wherein the first and second circuit boards are flexible printed circuit boards.