Light emitting diode (LED) and method of manufacture

• US 8,227,274 B2
• Filed: 01/26/2010
• Issued: 07/24/2012
• Est. Priority Date: 01/26/2010
• Status: Active Grant

• Current Assignee: Lightizer Co., Ltd.
• Original Assignee: Lightizer Korea Co.
• Inventors: Cho, Byoung gu
• Primary Examiner(s): Mandala, Victor A
• Assistant Examiner(s): Schoenholtz, Joseph
• Application Number:
  US12/693,632
• Publication Number:
  US 20110180829A1
• Time in Patent Office: 910 Days
• Field of Search: None
• US Class Current: 438/29
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• 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: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

The present invention provides an LED and method of manufacture in which white light is produced. Specifically, under the present invention, a wavelength of a light output by an LED (e.g., blue or ultra-violet (UV)) is measured (e.g., at the wafer level). Based on the wavelength measurement, a conformal coating is applied to the LED. The conformal coating has a phosphor ratio that is based on the wavelength. Moreover, the phosphor ratio is comprised of at least one of the following colors: yellow, green, or red. The light output of the LED is then converted to white light using the conformal coating. In a typical embodiment, these steps are performed at the wafer level so that uniformity and consistency in results can be better obtained. However, it should be understood that the same teachings could be applied at the chip level. Moreover, several different approaches can be implemented for isolating the coating area. Examples include the use of a paraffin wax, a silk screen, or a photo resist.

Claims

1. A method for manufacturing a light emitting diode (LED), comprising:

taking a measurement for the LED;

isolating an area of the LED using at least one of the following;

paraffin wax, a silk screen, or a photo resist;

applying a conformal coating to the area, the conformal coating having a phosphor ratio that is based on the measurement for each chip of the wafer; and

converting a light output of the LED to white light using the conformal coating.

2. The method of claim 1, wherein the measurement comprises a wavelength of the light output by the LED.

3. The method of claim 1, wherein the LED comprises a blue LED.

4. The method of claim 1, wherein the LED comprises an ultra-violet LED.

5. The method of claim 1, the conformal coating having a phosphor ratio comprising at least one of the following colors:

yellow, green, or red.

6. The method of claim 1, the LED being disposed on a wafer with a plurality of other LEDS, the conformal coating being applied to the wafer.

11. A light emitting diode (LED), manufactured according to the process of claim 1.

12. The LED of claim 11, wherein a phosphor ratio of the conformal coating is comprised of at least one of the following colors:

yellow, green, or red.

7. A method for manufacturing a light emitting diode (LED), comprising:

measuring a wavelength of a light output by the LED;

isolating an area of the LED using at least one of the following;

paraffin wax, a silk screen, or a photo resist;

applying a conformal coating to the area, the conformal coating having a phosphor ratio that is based on the wavelength, and the phosphor ratio comprised of at least one of the following colors;

yellow, green, or red; and

converting the light output of the LED to white light using the conformal coating.

8. The method of claim 7, the LED comprising a blue LED.

9. The method of claim 7, the LED comprising an ultra-violet LED.

10. A light-emitting diode (LED) manufactured according the process of claim 7.