FOOD QUALITY EXAMINATION DEVICE, FOOD COMPONENT EXAMINATION DEVICE, FOREIGN MATTER COMPONENT EXAMINATION DEVICE, TASTE EXAMINATION DEVICE, AND CHANGED STATE EXAMINATION DEVICE

摘要

There is provided, for example, a food quality examination device configured to inspect the quality of food with high sensitivity using an InP-based photodiode in which a dark current is decreased without a cooling mechanism and the sensitivity is extended to a wavelength of 1.8 µm or more. An absorption layer 3 has a multiquantum well structure composed of a III-V group semiconductor. A pn junction is formed by selectively diffusing an impurity element into the absorption layer. The concentration of the impurity in the absorption layer is 5 × 10 16 /cm 3 or less. The food quality examination device receives light having at least one wavelength of 3 µm or less within the absorption band of water, thereby performing the inspection.