Light emitting diode having a wavelength shift layer and method of manufacture

• US 8,017,417 B1
• Filed: 03/31/2010
• Issued: 09/13/2011
• Est. Priority Date: 03/31/2010
• Status: Active Grant

• Current Assignee: Lightizer Co., Ltd.
• Original Assignee: Lightizer Korea Co.
• Inventors: Cho, Byoung gu
• Primary Examiner(s): Geyer; Scott B
• Application Number:
  US12/750,816
• Publication Number:
  US 20110241024A1
• Time in Patent Office: 531 Days
• Field of Search: None
• US Class Current: 438/26
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• 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 2924/12044 OLED
• CPC Class Codes: H01L 2933/0041 relating to wavelength conversion elements
• CPC Class Codes: H01L 33/50 Wavelength conversion elements

Abstract

Embodiments of the present invention provide an LED having a Wavelength Shift Layer (WSL) and method of manufacture. Specifically, under embodiment of the present invention, a WSL layer is applied over an LED chip. The WSL itself typically comprises two layers: an adhesion layer applied over a set (at least one) of LED chips, and a conformal coating over the adhesion layer. The adhesion layer provides improved adhesive effect of the conformal coating to the LED chip(s). The conformal coating is comprised of a particular phosphor ratio that is determined based on a wavelength measurement of the underlying LED chip(s). Specifically, under the present invention, a wavelength of a light output by an LED chip(s) (e.g., blue or ultra-violet (UV)) is measured (e.g., at the wafer level). Typically, the phosphor ratio of is comprised of at least one of the following colors: yellow, green, or red. Regardless, this conformal coating is applied over a glue layer that itself is applied over the LED chip.

Claims

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

taking a measurement for a set of LED chips;

applying an adhesion layer over the set of LED chips;

isolating an area of the set of LED chips using at least one of;

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

applying a conformal coating to the isolated area over the adhesion layer, the conformal coating having a phosphor ratio that is based on the measurement; and

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

2. The method of claim 1, the adhesion layer comprising an adhesive selected from a group consisting of:

a silicon resin, an epoxy resin, an organic polymer, and a glass resin.

3. The method of claim 1, the measurement comprising a measurement of a wavelength of the light output by the set of LED chips.

4. The method of claim 1, further comprising applying a passivation layer over the conformal coating.

5. The method of claim 1, the set of LED chips comprising a blue set of LED chips.

6. The method of claim 1, the set of LED chips comprising an ultra-violet set of LED chips.

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

yellow, green, or red.

8. The method of claim 1, the set of LED chips being disposed on a wafer with a plurality of other sets of LED chips, the conformal coating being applied to the wafer.

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

measuring a wavelength of a light output by a set of LED chips;

applying an adhesion layer over the set of LED chips, the adhesion layer comprising an adhesive selected from a group consisting of;

a silicon resin, an epoxy resin, an organic polymer, and a glass resin;

isolating an area of the set of LED chips using at least one of;

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

applying a conformal coating to the isolated area of the set of LED chips, 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 set of LED chips to white light using the conformal coating.

10. The method of claim 9, further applying a passivation layer over the conformal coating.