Abstract: Disclosed is an improved photo detector, which includes a substrate, a light reception chip, and a coating layer. The substrate includes a first electrode member and a second electrode member. The light reception chip is set on the substrate and is electrically connected to the first and second electrode members of the substrate. The coating layer is formed on the light reception chip and functions to filter out visible light and allows only invisible light to transmit therethrough. As such, efficacies of receiving only visible light and minimizing the overall size can be realized.