Patent ID: 9685594
Date: 2017-06-20
CPC Classifications: F21K,H01L

Claim:
1. An LED module comprising: a submount having a face in a thickness direction of the submount; an LED chip bonded to the face with a first bond; a reflective layer provided on a further face of the submount in the thickness direction for reflecting light from the LED chip; a patterned wiring circuit electrically connected to the LED chip; and an opaque substrate, the first bond allowing light emitted from the LED chip to pass therethrough, the submount being a light-transmissive member having light diffusing properties and having a planar size larger than a planar size of the LED chip, the patterned wiring circuit being provided on the face of the submount so as not to overlap the LED chip, the submount being constituted by a first ceramic layer and a second ceramic layer which are stacked in the thickness direction, the first ceramic layer and the second ceramic layer being arranged from the LED chip in order of the first ceramic layer and the second ceramic layer, the first ceramic layer being thicker than the second ceramic layer, the first ceramic layer including ceramic particles having a greater particle diameter than the second ceramic layer, while the second ceramic layer includes ceramic particles having a smaller particle diameter than the first ceramic layer and the second ceramic layer further includes pores, the first ceramic layer and the second ceramic layer having different optical properties so that the second ceramic layer which is farther from the LED chip is higher than the first ceramic layer in reflectance in a wavelength range of the light emitted from the LED chip, the submount being bonded to a surface of the opaque substrate with a second bond, a silver paste being screen printed on a ceramic green paste, the silver paste formed onto the second ceramic layer, the silver paste being sintered to form the reflective layer, while the sintering also forms the second ceramic layer from the ceramic green paste such that the reflective layer is formed onto the second ceramic layer, and the surface of the opaque substrate having one of light diffusing properties or specular reflective properties.