Patent ID: 11921038
Assignee: ASAHI KASEI MICRODEVICES CORPORATION
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. An optical device comprising:
an optical filter having a substrate and a multilayer film having a plurality of layers with different refractive indexes formed on at least one side of the substrate; and
an infrared light emitting and receiving device having a semiconductor layer of a first conductive type, an active layer, and a semiconductor layer of a second conductive type; wherein
the multilayer film has a structure in which a first layer and a second layer are alternately stacked, the first layer has a refractive index of 1.2 or more and 2.5 or less in a wavelength range of 2400 nm to 6000 nm, and the second layer has a refractive index of 3.2 or more and 4.2 or less in a wavelength range of 2400 nm to 6000 nm; and
the optical filter includes a wavelength range having an average transmittance of 70% or more with a width of 50 nm or more in a wavelength range of 2400 nm to 6000 nm, and has a maximum transmittance of 5% or more in a wavelength range of 6000 nm to 8000 nm.