Imaging system

Abstract

Provided is an imaging system that can reduce noise in received infrared light data. The imaging system includes a light source that emits infrared light, and an imaging device that images an object irradiated with the infrared light emitted from the light source, wherein: the imaging system includes a first polarizer which is provided between the light source and the object and which polarizes the infrared light emitted from the light source; the imaging device includes, from the infrared light incident side, an absorption type second polarizer that polarizes the infrared light, and an image sensor; the image sensor includes a spectral filter layer and an imaging element; the spectral filter layer includes a multi-bandpass filter having transmission bands in the visible light band and a part of the infrared light band; and the full width at half maximum of the transmission band in the infrared light band of the multi-bandpass filter is 60 nm or less.

Claims

1. An imaging system comprising: a light source that emits infrared light; and an imaging device that images an object irradiated with the infrared light emitted from the light source, wherein the imaging device has a first polarizer provided between the light source and the object for polarizing the infrared light emitted from the light source; the imaging device comprises an absorption-type second polarizer for polarizing the infrared light from the incident side of the infrared light, and an image sensor; the image sensor comprises a spectral filter layer and an image sensor; the spectral filter layer has a multibandpass filter having transmission bands in the visible light band and a part of the infrared light band, respectively; and the half-width of the transmission band in the infrared light band of the multibandpass filter is 60 nm or less.

2. The imaging system according to claim 1, wherein the spectral filter layer includes a color filter having a red band filter region, a green band filter region, and a blue band filter region patterned to correspond to each pixel of the image sensor, and comprises an infrared light selective shielding member having a notch filter region for shielding infrared light transmitted through the multibandpass filter, which is arranged to correspond to the pixels on which the red band filter region, the green band filter region, and the blue band filter region are installed.

3. The imaging system according to claim 2, wherein the color filter includes, in addition to the red band filter region, the green band filter region, and the blue band filter region patterned to correspond to each pixel of the image sensor, an infrared light pass filter region that cuts the entire visible light band and transmits a portion of the infrared light band.

4. The imaging system according to any one of claims 1 to 3, wherein the second polarizer has a maximum absorption wavelength in the infrared light band.

5. The imaging system according to any one of claims 1 to 3, wherein the difference between the wavelength at which the absorbance of the absorption spectrum in the absorption axis direction of the second polarizer is maximum and the center wavelength of the transmission spectrum in the infrared band of the multibandpass filter is 50 nm or less, and the full width at half maximum of the absorption spectrum in the absorption axis direction of the second polarizer is greater than or equal to the full width at half maximum of the transmission spectrum in the infrared band of the multibandpass filter.

6. The imaging system according to claim 2 or 3, wherein, in the wavelength range of 600 nm to 700 nm, the area of ​​the overlap between the absorption spectrum in the absorption axis direction of the second polarizer and the transmission spectrum in the red band filter region of the color filter is 20% or less of the area of ​​the transmission spectrum in the red band filter region of the color filter.

7. The imaging system according to any one of claims 1 to 3, wherein the second polarizer includes a dichroic dye.

8. The half-maximum wavelength on the short-wavelength side of the absorption spectrum in the absorption axis direction of the second polarizer is λ p50 Let λ be the center wavelength of the transmission spectrum in the infrared band of the multibandpass filter in the case of 30° oblique incidence. bd Therefore, λ p50 <λ bd The imaging system according to any one of claims 1 to 3.

9. The imaging system according to any one of claims 1 to 3, wherein the full width at half maximum of the absorption spectrum of the second polarizer in the absorption axis direction is greater than the full width at half maximum of the emission spectrum of the light source.

10. The imaging system according to claim 2 or 3, wherein the average transmittance in the visible light band of the second polarizer is equal to or greater than the average transmittance in the visible light band of the notch filter region of the infrared light selective shielding member.

Images