Multichip light emitting diode (led) and method of manufacture

Abstract

The present invention provides a multichip LED and method of manufacture in which white light is produced. Specifically, a plurality of electrically interconnected LED chips (e.g., interconnected via red metal wire) is selected for conversion of light to white light. In a typical embodiment, the LED chips comprise: a blue LED chip, a red LED chip, a green LED chip, and a target LED chip whose light output is converted to white light. A wavelength of a light output by one or more of the plurality of chips will be measured. Based on the wavelength measurement, a conformal coating is applied to the one or more of the LED chips. 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. Using the conformal coating the light output of the target LED is then converted to white light. In a typical embodiment, these steps are performed at the wafer level so that uniformity and consistency in results can be better obtained. 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. Regardless, this approach allows multiple chips to be treated simultaneously.