Optical Directivity Design Using Through-hole Array Silicon Chip

Abstract

In this letter, we report a method of designing the optical sensor directivity without using an optical lens. The directivity is realized by attaching the designed through-hole array chip on an optical sensor surface. The through-hole array chip can be formed by a conventional semiconductor manufacturing technique. The directivity can be designed by adjusting the through-hole size and the chip thickness. Its performance is evaluated using the manufactured test chip. For visible light, when the through hole width is $25~\mu \text{m}$ and the partition wall thickness between them is $10~\mu \text{m}$ , the directivity is about 4 ° and the light transmittance is about 31%. Although directivity is slightly broad for near-infrared light, it can be designed utilizing the trade-off between directivity and transmittance. The proposed method enables us to reduce the sensor size to one-tenth or less of that using optical lenses.