Light emitting mesa structures with high aspect ratio and near-parabolic sidewalls
US7518149B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 2005 |
| Grant date | Apr 14, 2009 |
| Priority date | — |
| Expiry date | Jul 20, 2026 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E10/50
Abstract
An array of highly efficient micro-LEDs where each micro-LED is an integrated diode structure in a mesa, in which the mesa shape and the light-emitting region are chosen for optimum efficiency. A single one of the micro-LEDs includes, on a substrate and a semiconductor layer, a mesa, a light emitting layer, and an electrical contact. The micro-LEDs in this device have a very high EE because of their shape. Light is generated within the mesa, which is shaped to enhance the escape probability of the light. Very high EEs are achieved, particularly with a near parabolic mesa that has a high aspect ratio. The top of the mesa is truncated above the light-emitted layer (LEL), providing a flat surface for the electronic contact on the top of the semiconductor mesa. It has been found that the efficiency is high, provided the top contact has a good reflectivity value. Also, it has been found that efficiency is particularly high if the contact occupies an area of less than 16% of the truncated top mesa surface area. This feature also helps to achieve a more directional beam in the case of the device being an LED.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.