Industrial Technology Research Institute

Epistar Corporation

Fei-Chang Hwang

Ming-Te Lin

Chia-Tai Kuo

Sheng-Pan Huang

Chao-Nien Huang

Chiu-Ling Chen

Chin-Yuan Chen

Eric G Lean

Ming-Huang Hong

An arrangement of light emitting diodes including a first micro-die, a second micro-die, a first bridge, a second bridge and a substrate supporting the first micro-die and the second micro die. The first micro-die includes a first edge having a first end and a second end, a second edge opposite and not parallel to the first edge, a first connecting portion near the first end, and a second connecting portion near the second end.

Structure of AC light-emitting diode dies

A structure of light-emitting diode (LED) dies having an AC loop (a structure of AC LED dies), which is formed with at least one unit of AC LED micro-dies disposed on a chip. The unit of AC LED micro-dies comprises two LED micro-dies arranged in mutually reverse orientations and connected with each other in parallel, to which an AC power supply may be applied so that the LED unit may continuously emit light in response to a positive-half wave voltage and a negative-half wave voltage in the AC power supply. Since each AC LED micro-die is operated forwardly, the structure of AC LED dies also provides protection from electrical static charge (ESD) and may operate under a high voltage.

A life test device comprises an oven, a current source, a voltage meter, a control module, and a process module. A light-emitting diode (LED) is disposed in the oven. The temperature of the oven is gradually changed in a first period and remains at a set temperature in a second period. The current source provides a first current and a second current to the LED. The voltage meter measures forward voltages of the LED. The control module controls the current source to output the first or second current to the LED and controls the voltage meter to measure the forward voltages of the LED. The process module calculates a junction temperature of the LED according to the forward voltages and a variation relationship formula between the forward voltages and the temperature of the oven.

Devices and methods for LED life test

A white light-emitting diode and a method of fabricating the same diode are disclosed. The white light-emitting diode is fabricated by epitaxy, which can produce two peaks in the spectrum at the P-N junction by appropriately adjusting epitaxial parameters such as temperature, pressure, NH.sub.3 flux and the ratio of H.sub.2 to N.sub.2 or the concentration of dopant, such as Mg or Si. The diode can thus radiate white light by adjusting the wavelength and the intensity of the principal peak in the two peaks. Further, quantum well structure can be formed in the diode. By appropriately adjusting the epitaxial parameters, the spectrum of the quantum well structures may have more than one peak. Therefore, white light can be generated by combining the light with wavelengths at two or three different peaks. The white LED can radiate white light itself and need not involve combining many LEDs, so that the cost and the difficulty of fabricating the white LED lamp can be reduced. Moreover, the white LED can radiate white light itself, and does not need to excite fluorescent material to radiate white light. Accordingly, the lifetime of the white LED lamp is not limited by the relatively short lifetime of fluorescent material.

Growing community of inventors

Hsinchu, Taiwan

Fei-Chang Hwang