Illuminance sensor chip and illuminance sensor incorporating the same

摘要

An illuminance sensor chip includes a first semiconductor layer, and a second semiconductor layer joined to the first semiconductor layer. When light is incident on the junction between the first semiconductor layer and the second semiconductor layer, the sensor chip outputs an electric signal in accordance with an amount of light incident on the junction. The thickness D of the second semiconductor layer is set to 2-4 mum for example so that the peak sensitivity wavelength in the spectral sensitivity characteristics lies in a visible light wavelength range. An illuminance sensor further includes, besides the above-described illuminance sensor chip, an additional illuminance sensor chip which is identical or generally identical to the first-mentioned illuminance sensor chip in spectral sensitivity characteristics. The additional illuminance sensor chip is provided with a visible light shielding portion for absorbing visible light. The illuminance is calculated based on the outputs from the illuminance sensor and the additional illuminance sensor.