Optical lens, light emitting device package using the optical lens, and backlight unit

• US 20060238884A1
• Filed: 04/26/2006
• Published: 10/26/2006
• Est. Priority Date: 04/26/2005
• 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, Seo, Jung Hoon
• Granted Patent: US 7,602,559 B2
• Time in Patent Office: Days
• US Class Current: 359/653
• CPC Class Codes: F21V 5/04 of lens shape
• CPC Class Codes: F21V 7/0091 using total internal reflection
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0061 the light source comprising a LED semiconductor devices with at least one potential-jump barrier or surface barrier specially adapted for light emission H01L33/00
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 19/0071 adapted to illuminate a complete hemisphere or a plane extending 360 degrees around the source
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133605 including specially adapted reflectors

Abstract

An optical lens, a light emitting device package using the optical lens and a backlight unit are disclosed, whereby light irradiated upward of a light emitting device is refracted from a bottom refraction surface to allow reaching a reflection surface, and an optical lens is mounted for reflecting the light sideways of the lens from the reflection surface to minimize an amount of light irradiated upward of the lens while increasing the amount of light irradiated toward the lateral surface of the lens, thereby limiting the generation of a hot spot to the maximum. The present invention dispenses with a hot spot baffle plate and a complicated assembly process to enable to reduce the number of parts and to decrease the thickness of a panel.

Claims

1. An optical lens comprising:

a reflection surface formed thereon for reflecting light emitted upwards from a bottom thereof; and

a bottom refraction surface for refracting the light emitted upwards from the bottom thereof to allow reaching the reflection surface.

2. The lens as defined in claim 1, wherein the reflection surface is inclined, and the bottom refraction surface is symmetrically inclined from the reflection surfaces with respect to a horizontal line.

3. The lens as defined in claim 1 further comprising an external refraction surface laterally formed for refracting the light reflected from the reflection surface and the light irradiated toward a bottom lateral surface thereof to allow laterally being emitted.

4. The lens as defined in claim 3, wherein a body of the optical lens including the reflection surface, the bottom refraction surface and the external refraction surface is shaped of a hemisphere.

5. The lens as defined in claim 1, wherein the reflection surface is coated with a reflective film.

6. A light emitting device package comprising:

a light emitting device for emitting light; and

an optical lens disposed with a reflection surface formed thereon for reflecting light emitted upwards from the light emitting device and a bottom refraction surface for refracting the light emitted upwards from the light emitting device and allowing the light to reach the reflection surface.

7. The package as defined in claim 6 further comprising:

a base member on which the light emitting devices are bonded;

terminals electrically connected to the light emitting devices; and

a molding unit for partially exposing the terminals and encompassing the light emitting devices and the base member, wherein the optical lens is attached to an upper surface of the molding unit.

8. The package as defined in claim 7, wherein the base member is a hit slug or a sub-mount substrate.

9. The package as defined in claim 7, wherein the light emitting device is made of one of a group consisting of:

devices including a blue light emitting device for emitting blue light and a yellow light emitting device for emitting yellow light;

devices including a red light emitting device for emitting red light, a green light emitting device for emitting green light and a blue light emitting device for emitting blue light; and

a single light emitting device for emitting white light.

10. The package as defined in claim 6 further comprising an external refraction surface formed at a lateral surface of the optical lens for refracting light reflected from the reflection surface and light irradiated to the lateral surface of the light emitting device to be irradiated to the lateral surface of the optical lens.

11. The package as defined in claim 10, wherein the body of the optical lens composed of the reflection surface, the bottom refraction surface and the external refraction surface is shaped of a hemisphere.

12. The package as defined in claim 6, wherein the reflection surface is inclined, and the bottom refraction surface has an inclination symmetrically inclined from the reflection surface.

14. The package as defined in claim 6, wherein the bottom refraction surface is concaved.

15. The package as defined in claim 6, wherein the reflection surface is coated with a reflective film.

16. The package as defined in claim 15, wherein the reflective film is further coated thereon with non-permeable material film.

13. The package as defined in 12, wherein the bottom reflection surface further comprises a marginal refraction surface symmetrically inclined from the bottom refraction surface relative to a perpendicular line for refracting light in such a manner that light emitted from an upper margin of the light emitting device can have a path on which the light is reflected from the reflection surface.

17. A backlight unit comprising:

a substrate;

a plurality of light emitting devices packaged in the substrate for emitting light;

a plurality of optical lenses disposed with a reflection surface formed thereon for reflecting light emitted upwards from the plurality of light emitting devices and a bottom refraction surface for refracting the light emitted upwards from the plurality of light emitting devices and allowing the light to reach the reflection surface; and

a diffusion plate disposed on the plurality of optical lenses.

18. The backlight unit as defined in claim 17, wherein the diffusion plate is disposed thereon with a liquid crystal display panel.

19. The backlight unit as defined in claim 17 further comprising an external refraction surface formed at a lateral surface of the optical lens for refracting light reflected from the reflection surface and light irradiated to the lateral surface of the light emitting device to be irradiated to the lateral surface of the optical lens.

20. The backlight unit as defined in claim 19, wherein the body of the optical lens composed of the reflection surface, the bottom refraction surface and the external refraction surface is shaped of a hemisphere.