| 摘要 |
PURPOSE:To obtain the same brightness even with an irregularity in a light-emitting element by a method wherein the light-emitting element composed of a compound semiconductor layer and a photodetector composed of a compound semiconductor layer and positioned so as to detect a beam from the light-emitting element are installed on an Si substrate and, in addition, a drive circuit used to make an optical output of the light-emitting element constant by using an output signal of the photodetector is installed. CONSTITUTION:A light-emitting element 201 such as an LED or the like and a photodetector 202 such as a photodiode or the like are formed on a compound semiconductor layer which has been epitaxially grown on an Si substrate. During this process, a position of the element 202 is limited in an area where a beam of light from the element 201 can be detected. In addition, a drive circuit 203 composed of a MOSFET or the like is installed to be adjacent to these elements; a beam of light emitted from the light-emitting element 201 by a drive current I from the drive circuit is detected by using the photodetector 202; a photoelectric current Ip corresponding to the light intensity is applied to the circuit 203; the I is controlled in such a way that the Ip becomes constant; the optical output is kept always stable. By this setup, even when temperature is changed, the current Ip is made constant and a device is made long-lived as a whole. |
