LED ARRAY, PRINT HEAD, AND ELECTROPHOTOGRAPHIC PRINTER

摘要

PROBLEM TO BE SOLVED: To provide an LED which radiates a large amount of light and has a small connection resistance to a p-side electrode. SOLUTION: An LED 10 has an opening part 16 in an interlayer insulating film 12 formed on an n-type semiconductor substrate. A p-type diffusion region is formed at a substrate region corresponding to the opening part 16. A p-side electrode 14 is formed to be connected with the p-type diffusion region. The LED 10 is thus constituted. The LEDs 10 are arranged linearly with a pitch P, thereby forming an LED array. In order to make both a resolution and uniformity of radiation light compatible, a breadth W0 of a surface part 17 which is a substrate surface region of the p-type diffusion region is set to satisfy 0.4P<=W0<=0.5P. An area SO of the surface part 17, an area S2 of a covering part 17a which is an area of the p-side electrode 14 covering the surface part 17, and an area S3 of a connecting part 16a which is an area of the p-side electrode 14 connected to the p-type diffusion region are set to satisfy 0.25S0<=S2<=0.5S0 and S3>=0.4S2 so as to make the amount of radiation light large and a connection resistance of the p-side electrode 14 small.