Image sensor unit and image taking apparatus
The present invention relates to an image sensor unit including an image sensor that generates an image signal and a filter, and to an image taking apparatus that receives light from a subject and generates an image signal. The image sensor unit and the image taking apparatus achieve excellent photographing through day and night. They are provided with a filter including a transparent layer that is transparent to light in a visible light region regardless of the state of an electric field and is transparent to light in a predetermined variable transparent region containing an infrared light region and/or an ultraviolet light region in response to the state of the electric field, and electrodes that generate the electric field in the transparent layer on the application of a voltage.
1. A image taking apparatus that receives light from a subject and generates an image signal, comprising:
(A) an image sensor unit including:
(a) an image sensor that receives the light from the subject and generates the image signal, and
(b) a filter that is disposed in front of the image sensor, having:
(b-1) a transparent layer that is transparent to light in a visible light region regardless of the state of an electric field and is transparent to light in a predetermined variable transparent region containing an infrared light region and/or an ultraviolet light region in response to the state of the electric field, and
(b-2) electrodes that generate the electric field in the transparent layer on the application of a voltage; and
(B) a filter controller that regulates the wavelength region of light passing through the filter by controlling the voltage applied to the electrodes; and
wherein the transparent layer is composed of a dispersion medium that is transparent to the light in the visible light region and the variable transparent region, and dispersoids that are dispersed in the dispersion medium, the dispersoids being impermeable to the light in the variable transparent region and transparent to the light in the visible light region.
2. The image taking apparatus according to claim 1 , further comprising:
a sensor that determines the brightness of the subject,
wherein the filter controller applies a voltage depending on a measurement obtained with the sensor.
3. The image taking apparatus of claim 1 , further comprising:
a mechanical iris on an incident light side of said filter.
4. The image sensor unit according to claim 1 , wherein the dispersoids are nanoparticles containing infrared absorbing material.
5. The image sensor unit according to claim 1 , wherein the dispersoids are polymer particles containing infrared absorbing material.
6. The image sensor unit according to claim 1 , wherein the dispersion medium is an organic dispersion medium.
7. The image sensor unit according to claim 1 , wherein the dispersion medium is a hydrocarbon-based organic dispersion medium.
8. An image taking apparatus that receives light from a subject and generates an image signal, comprising:
(A) an image sensor unit including:
(a) an image sensor that receives the light from the subject and generates the image signal, and
(b) a filter that is disposed in front of the image sensor, having:
(b-1) a transparent layer that is transparent to light in a visible light region regardless of the state of an electric field and is transparent to light in a predetermined variable transparent region containing an infrared light region and/or an ultraviolet light region in response to the state of the electric field, and
(b-2) electrodes that generate the electric field in the transparent layer on the application of a voltage; and
(B) a filter controller that regulates the wavelength region of light passing through the filter by controlling the voltage applied to the electrodes, and
wherein the transparent layer is a liquid crystal layer in which the orientation of liquid crystal molecules varies in response to the state of the electric field, and the liquid crystal layer changes between an off-state, in which the light in the visible light region and the variable transparent region passes through the liquid crystal layer, and an on-state, in which only the light in the variable transparent region is absorbed or reflected and the light in the visible light region passes through the liquid crystal layer, in a manner that depends on the orientation of the liquid crystal molecules.
9. The image sensor unit according to claim 8 , wherein the transparent layer is a holographic liquid crystal layer.
10. The image sensor unit according to claim 8 , wherein the transparent layer is a cholesteric liquid crystal layer.