Etendue enhancement for light emitting diode subpixels

US10707374B2 · kind B2 · utility

Assignee

• GLO AB · SE

Inventors

• Fariba Danesh · Los Altos Hills, US
• Benjamin Leung · Sunnyvale, US
• Tsun LAU · Sunnyvale, US
• Zulal TEZCAN · Sunnyvale, US
• Miao-Chan Tsai · Sunnyvale, US
• Max Batres · Lompoc, US
• Michael J. Cich · Fremont, US

Key dates

• Filing date: Sep 6, 2018
• Grant date: Jul 7, 2020
• Expiry date: Sep 6, 2038

Classification

• Technology area (CPC H): Electricity
• CPC primary: H10H20/0363
• WIPO field: Semiconductors
• WIPO sector: Electrical engineering

Abstract

A method of forming a light emitting device includes forming a growth mask layer including openings on a doped compound semiconductor layer, forming first light emitting diode (LED) subpixels by forming a plurality of active regions and second conductivity type semiconductor material layers employing selective epitaxy processes, and transferring each first LED subpixel to a backplane. An anode contact electrode may be formed on the second conductivity type semiconductor material layers for redundancy. The doped compound semiconductor layer may be patterned with tapered sidewalls to enhance etendue. An optically clear encapsulation matrix may be formed on the doped compound semiconductor material layer to enhance etendue. Lift-off processes may be employed for the active regions. Cracking of the LEDs may be suppressed employing a thick reflector layer.