Abstract: In a color separation prism that includes a first and second prism blocks bonded to each other, the first and second prism blocks are bonded to the first and second adhesive portions of the first and second base plates, respectively. The first and second base plates are fixed to the first and second base plate-fixing portions of a base with the first and second base-fixing portion interposed therebetween, respectively. The second adhesive portion is disposed between the first and second base plate-fixing portions so that a direction in which the second base plate-fixing portion is displaced from the first base plate-fixing portion and a direction in which the second adhesive portion is displaced from the second base-fixing portion are opposite to each other in a case in which the base and the second base plate expand or contract due to a change in temperature.

Abstract: In a color separation prism that includes a first and second prism blocks bonded to each other, the first and second prism blocks are bonded to the first and second adhesive portions of the first and second base plates, respectively. The first and second base plates are fixed to the first and second base plate-fixing portions of a base with the first and second base-fixing portion interposed therebetween, respectively. The second adhesive portion is disposed between the first and second base plate-fixing portions so that a direction in which the second base plate-fixing portion is displaced from the first base plate-fixing portion and a direction in which the second adhesive portion is displaced from the second base-fixing portion are opposite to each other in a case in which the base and the second base plate expand or contract due to a change in temperature.

Abstract: A color separation optical assembly (3) of an image capture device (1) includes, in order from a light incidence side, a first prism (10) which has a first dichroic film (D1) and extracts blue light (LB) reflected by the first dichroic film, a second prism (20) which has a second dichroic film (D2) and extracts red light (LR) transmitted through the first dichroic film and reflected by the second dichroic film, and a third prism (30) which extracts green light (LG) transmitted through the first and second dichroic films. The first dichroic film is a multiband dichroic film which reflects light of an infrared region from a long wavelength side of a red region.

Abstract: A color separation optical assembly (3) of an image capture device (1) includes, in order from a light incidence side, a first prism (10) which has a first dichroic film (D1) and extracts blue light (LB) reflected by the first dichroic film, a second prism (20) which has a second dichroic film (D2) and extracts red light (LR) transmitted through the first dichroic film and reflected by the second dichroic film, and a third prism (30) which extracts green light (LG) transmitted through the first and second dichroic films. The first dichroic film is a multiband dichroic film which reflects light of an infrared region from a long wavelength side of a red region.

Abstract: A lens device (2) is provided with a first operating ring (11) for adjusting the opening surface area of an aperture device (15) and a second operating ring (12) for adjusting the transmittance of a variable light transmittance filter (16). The correspondence relation between the operational amount for the first operating ring and the rate of change in the amount of light transmitted by the aperture device and correspondence relation between the operational amount for the second operating ring and the rate of change in the amount of light transmitted by the variable light transmittance filter are the same.

Abstract: When a exposure controlling unit changes an aperture value of a diaphragm in a predetermined range, the exposure controlling unit also changes a transmittance of a variable ND filter so as to perform an exposure control and, after obtaining a proper exposure by changing both the aperture value and the transmittance, sets the aperture value after exposure control to Fa, and in a case where the aperture value at which a maximum resolving power is obtained is set to Fb, when a condition, Fa?Fb, is satisfied and the transmittance is neither the minimum nor the maximum, the exposure controlling unit brings the aperture value close to Fb and changes the transmittance so as to maintain the proper exposure after the exposure control.

Abstract: A lens device (2) is provided with a first operating ring (11) for adjusting the opening surface area of an aperture device (15) and a second operating ring (12) for adjusting the transmittance of a variable light transmittance filter (16). The correspondence relation between the operational amount for the first operating ring and the rate of change in the amount of light transmitted by the aperture device and correspondence relation between the operational amount for the second operating ring and the rate of change in the amount of light transmitted by the variable light transmittance filter are the same.

Abstract: When a exposure controlling unit changes an aperture value of a diaphragm in a predetermined range, the exposure controlling unit also changes a transmittance of a variable ND filter so as to perform an exposure control and, after obtaining a proper exposure by changing both the aperture value and the transmittance, sets the aperture value after exposure control to Fa, and in a case where the aperture value at which a maximum resolving power is obtained is set to Fb, when a condition, Fa?Fb, is satisfied and the transmittance is neither the minimum nor the maximum, the exposure controlling unit brings the aperture value close to Fb and changes the transmittance so as to maintain the proper exposure after the exposure control.

Abstract: A color separating optical system including first to third prisms for separating incident light from an objective lens into three primary color light components, so as to project three color-separated images of a subject onto first to third image sensors, respectively. In order to prevent ghosts from being superposed on a center area of an image frame, the color separating optical system satisfies the condition: ??(?m+?m+1)/2, wherein “?” represents a tilt angle of a second dichroic film on the second prism to a perpendicular plane to an optical axis of the objective lens, and “?m” a diffraction angle of the second light component diffractively reflected from the second image sensor and reentering the second prism.

Abstract: A color separating optical system including first to third prisms for separating incident light from an objective lens into three primary color light components, so as to project three color-separated images of a subject onto first to third image sensors, respectively. In order to prevent ghosts from being superposed on a center area of an image frame, the color separating optical system satisfies the condition: ??(?m+?m+1)/2, wherein “?” represents a tilt angle of a second dichroic film on the second prism to a perpendicular plane to an optical axis of the objective lens, and “?m” a diffraction angle of the second light component diffractively reflected from the second image sensor and reentering the second prism.

Abstract: It is disclosed that a color separation optical system improves color reproducibility by obtaining a characteristic which approximates an ideal spectral characteristic in view of influence of polarization separation caused according to the magnitude of an incidence angle. In the color separation optical system, a curve representing a characteristic of a green-reflecting dichroic film DG has a shape along the characteristic curve representing an ideal spectral characteristic corresponding to green light. Further, the characteristic of the blue-reflecting dichroic film DB is associated with that of the green-reflecting dichroic film DG. A part, in which the transmittance of the blue-reflecting dichroic film DB changes from a low transmittance to a high transmittance, in the transmittance characteristic curve representing the characteristic of the blue-reflecting dichroic film DB is included in a predetermined wavelength region associated with the characteristic of the green-reflecting dichroic film DG.

Abstract: The present invention provides a visible and infrared light image-taking optical system which can facilitate changing a wavelength of infrared light used to take an infrared video image with an infrared light camera and which can achieve an infrared video image not affected by infrared light of any wavelength other than a desired wavelength, by separating object light incident on an image-taking optical system into object light in a visible light region and object light in an infrared light region and taking an object image formed by each object light for each object light in each wavelength region decomposed by the color separation optical system.

Abstract: A curve representing a characteristic of a blue-light reflecting dichroic film DB and a curve representing a characteristic of a red-light reflecting dichroic film DR are configured to have shapes that track an ideal spectral characteristic of green. Accordingly, it is possible to obtain a characteristic approximated to the ideal spectral characteristic without using a trimming filter having a dichroic film in an exiting surface of a prism. Since it is not necessary to use the trimming filter having the dichroic film, it is possible to prevent ghost and flare from occurring due to the dichroic film of the trimming filter. Accordingly, it is possible to embody an imaging apparatus having the ideal spectral characteristic with ghost and flare being reduced.

Abstract: An ND filter, comprising: A transparent board formed in a disk shape, wherein two or more regions having light transmittances differing stepwise from one another are continuously formed in a circumferential direction of the transparent board formed in a disk shape.

Abstract: It is disclosed that a color separation optical system improves color reproducibility by obtaining a characteristic which approximates an ideal spectral characteristic in view of influence of polarization separation caused according to the magnitude of an incidence angle. In the color separation optical system, a curve representing a characteristic of a green-reflecting dichroic film DG has a shape along the characteristic curve representing an ideal spectral characteristic corresponding to green light. Further, the characteristic of the blue-reflecting dichroic film DB is associated with that of the green-reflecting dichroic film DG. A part, in which the transmittance of the blue-reflecting dichroic film DB changes from a low transmittance to a high transmittance, in the transmittance characteristic curve representing the characteristic of the blue-reflecting dichroic film DB is included in a predetermined wavelength region associated with the characteristic of the green-reflecting dichroic film DG.

Abstract: A curve representing a characteristic of a blue-light reflecting dichroic film DB and a curve representing a characteristic of a red-light reflecting dichroic film DR are configured to have shapes that track an ideal spectral characteristic of green. Accordingly, it is possible to obtain a characteristic approximated to the ideal spectral characteristic without using a trimming filter having a dichroic film in an exiting surface of a prism. Since it is not necessary to use the trimming filter having the dichroic film, it is possible to prevent ghost and flare from occurring due to the dichroic film of the trimming filter. Accordingly, it is possible to embody an imaging apparatus having the ideal spectral characteristic with ghost and flare being reduced.

Abstract: The present invention provides a visible and infrared light image-taking optical system which can facilitate changing a wavelength of infrared light used to take an infrared video image with an infrared light camera and which can achieve an infrared video image not affected by infrared light of any wavelength other than a desired wavelength, by separating object light incident on an image-taking optical system into object light in a visible light region and object light in an infrared light region and taking an object image formed by each object light for each object light in each wavelength region decomposed by the color separation optical system.

Abstract: An attachment structure is used for attaching a solid-state imaging device to a light exit end face of a color-separating prism. When bonding the light exit end face on the color-separating prism side and the light entrance face on the solid-state imaging device side to each other, an adhesive is applied to a predetermined position between these faces outside a region through which a luminous flux incident on the imaging section of the solid-state imaging device passes.

Abstract: In a color separating optical system, a first filter adapted to eliminate from light emitted from a red light exit face a light component in a wavelength range longer than a longer-wavelength-side boundary wavelength of a red visible light wavelength region is disposed at a prism surface in an optical path for guiding red region light, whereas a second filter adapted to reflect a light component in a wavelength range longer than a reference wavelength which is longer than the longer-wavelength-side boundary wavelength by a predetermined wavelength but transmit therethrough a light component in a wavelength region shorter than the reference wavelength is placed at the red light exit face.

Abstract: An attachment structure is used for attaching a solid-state imaging device to a light exit end face of a color-separating prism. When bonding the light exit end face on the color-separating prism side and the light entrance face on the solid-state imaging device side to each other, an adhesive is applied to a predetermined position between these faces outside a region through which a luminous flux incident on the imaging section of the solid-state imaging device passes.