Backlight unit having light emitting diodes and method for manufacturing the same

• US 20060268567A1
• Filed: 05/30/2006
• Published: 11/30/2006
• Est. Priority Date: 05/30/2005
• Status: Active Grant

• Current Assignee: Suzhou Lekin Semiconductor Company Limited
• Original Assignee: LG Electronics, Inc. (LG Corporation), LG Innotek Company Limited (LG Corporation)
• Inventors: Jang, Jun Ho, Yee, Young Joo
• Granted Patent: US 7,427,145 B2
• Time in Patent Office: Days
• US Class Current: 362/555
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: Y10S 362/80 Light emitting diode

Abstract

A backlight unit having light emitting diodes and a method for manufacturing the same are disclosed, whereby a hot spot is not generated without recourse to use of a conventional lateral light emitting diode package to enable to improve a picture quality, and the method dispenses with an assembling process of placing a hot spot baffle plate to enable to simplify a manufacturing process of a backlight unit, and to reduce a thickness of the backlight unit.

Claims

1. A backlight unit having light emitting diodes comprising:

a substrate disposed thereon with conductive lines;

a plurality of light emitting diodes each bonded to an upper surface of the substrate and spaced a predetermined distance apart from the substrate, and electrically connected to the conductive lines of the substrate;

a transparent resin encompassing the plurality of light emitting diodes and formed on the upper surface of the substrate; and

optical transmission means disposed on an upper surface of the transparent resin, the means including first means for preventing light emitted from the light emitting diodes from being totally reflected by allowing an incident angle of the light to be less than a threshold angle, and second means for diffusing and emitting the light.

2. The unit as defined in claim 1, wherein the substrate is further formed thereon with a plurality of grooves, and each floor surface of the plurality of grooves is bonded to the light emitting diode.

3. The unit as defined in claim 2, wherein inner surfaces of the plurality of grooves are further coated with reflection layer.

4. The unit as defined in claim 2, wherein inner surface walls of the grooves are inclined.

5. The unit as defined in claim 1, wherein the substrate is a metal substrate, the metal substrate is further formed thereon with an insulation layer, and a conductive line of the substrate is formed on an upper surface of the insulation layer.

6. The unit as defined in claim 2, wherein each interior of the plurality of grooves is bonded to a sub-mount substrate formed thereon with a groove, a floor surface of the groove formed with a conductive pattern, and formed thereon with a conductive line electrically connected to the conductive pattern, and wherein each light emitting diode is flip-chip bonded to the conductive pattern existing on the floor surface of the groove of the sub-mount substrate, and the conductive line of the sub-mount substrate and the conductive line of the substrate are wire-bonded.

7. The unit as defined in claim 6, wherein the substrate is a metal substrate, and wherein the metal substrate is further formed thereon with an insulation layer, and the conductive line of the substrate is formed on an upper surface of the insulation layer.

8. The unit as defined in claim 1, wherein the first means of the optical transmission means is a micro lens array sheet on which a plurality of lenses are arrayed, and the second means is a light guide plate.

9. The unit as defined in claim 8, wherein the optical transmission means is configured in such a manner that the light guide plate is positioned on the transparent resin, and the light guide plate is positioned thereon with the micro lens array sheet, where a sheet surface not formed with the lenses of the micro lens array sheet contacts the light guide plate.

10. The unit as defined in claim 8, wherein the optical transmission means is configured in such a manner that the transparent resin is positioned thereon with the micro lens array sheet, and the micro lens array sheet is positioned thereon with the light guide plate, where a sheet surface formed with the lenses of the micro lens array sheet contacts the transparent resin.

11. The unit as defined in claim 8, wherein the optical transmission means is configured in such a manner that the transparent resin is positioned thereon with the light guide plate, and the light guide plate is positioned thereon with the micro lens array sheet, where a sheet surface formed with the lenses of the micro lens array sheet contacts the light guide plate.

12. The unit as defined in claim 1, wherein a margin of the substrate further comprises a ring-shaped guide part, and wherein the transparent resin is transformed in such a manner that a liquid transparent resin is coated on an inside of the guide part and the coated transparent resin is hardened to become a solid transparent resin.

13. The unit as defined in claim 12, wherein an inner wall of the ring-shaped guide part is inclined.

14. A backlight unit having light emitting diodes comprising:

a substrate;

a plurality of light emitting diodes each packaged to an upper surface of and spaced a predetermined distance apart from the substrate;

a guide substrate formed therein with a plurality of through holes each correspondingly positioned to the plurality of light emitting diodes, and bonded to an upper surface of the substrate; and

optical transmission means disposed on an upper surface of the guide substrate, the means including first means for preventing light emitted from the light emitting diodes from being totally reflected by allowing an incident angle of the light to be less than a threshold angle, and second means for diffusing and emitting the light.

15. The unit as defined in claim 14, wherein an inner wall of each through hole at the guide substrate is inclined.

16. The unit as defined in claim 14, wherein the substrate is a metal substrate, and wherein the metal substrate is further formed thereon with an insulation layer, and a conductive line of the substrate is formed on an upper surface of the insulation layer.

17. The unit as defined in claim 14, wherein the through holes of the guide substrate further comprise a transparent resin layer wrapping and coated on the light emitting diode.

18. The unit as defined in claim 14, wherein the first means of the optical transmission means is a micro lens array sheet on which a plurality of lenses are arrayed, and the second means is a light guide plate.

19. The unit as defined in claim 14, wherein the optical transmission means is configured in such a manner that the light guide plate is positioned on the guide substrate, and the light guide plate is positioned thereon with the micro lens array sheet, where a sheet surface not formed with the lenses of the micro lens array sheet contacts the light guide plate.

20. The unit as defined in claim 14, wherein the optical transmission means is configured in such a manner that the guide substrate is positioned thereon with the micro lens array sheet, and the micro lens array sheet is positioned thereon with the light guide plate, where a sheet surface formed with the lenses of the micro lens array sheet contacts the transparent resin.

21. The unit as defined in claim 14, wherein the optical transmission means is configured in such a manner that the guide substrate is positioned thereon with the light guide plate, and the light guide plate is positioned thereon with the micro lens array sheet, where a sheet surface formed with the lenses of the micro lens array sheet contacts the light guide plate.

22. A method for manufacturing a backlight unit having light emitting diodes comprising:

bonding a plurality of light emitting diodes to an upper surface of a substrate where conductive lines are disposed, each diode spaced a predetermined distance apart, and electrically connecting the plurality of light emitting diodes to the conductive lines of the substrate;

encompassing the plurality of light emitting diodes and forming a transparent resin layer on the upper surface of the substrate; and

positioning optical transmission means on an upper surface of the transparent resin layer, the means including first means for preventing light emitted from the light emitting diodes from being totally reflected by allowing an incident angle of the light to be less than a threshold angle, and second means for diffusing and emitting the light.

26. The method as defined in claim 22, wherein the first means of the optical transmission means is a micro lens array sheet on which a plurality of lenses are arrayed, and the second means is a light guide plate.

23. A method for manufacturing a backlight unit having light emitting diodes comprising:

packaging a plurality of light emitting diodes on an upper surface of a substrate, each diode spaced a predetermined distance apart;

preparing a guide plate formed with a plurality of through holes each hole spaced a predetermined distance apart;

bonding to the substrate the guide plate formed with the plurality of through holes so that each light emitting diode can be correspondingly positioned at each inner side of the through holes of the guide plate; and

positioning optical transmission means on an upper surface of the guide substrate, the means including first means for preventing light emitted from the light emitting diodes from being totally reflected by allowing an incident angle of the light to be less than a threshold angle, and second means for diffusing and emitting the light.

24. The method as defined in claim 23 further comprising a coating step of the transparent resin so that the light emitting diodes in the through holes of the guide plate can be wrapped by the transparent resin, in between the step of bonding the guide plate to the upper surface of the substrate and the step of positioning the optical transmission means.

25. The method as defined in claim 23, wherein each inner wall of the through holes of the guide plate is inclined.

27. The method as defined in claim 23, wherein the first means of the optical transmission means is a micro lens array sheet on which a plurality of lenses are arrayed, and the second means is a light guide plate.