Abstract: The invention provides a lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis, and said aperture is substantially trapezoidal.

Abstract: The invention provides a projector having a light source, a display device to modulate light emitted from the light source, a lens device to project light emitted from the light source via the display device, wherein the lens device has a diaphragm mechanism formed having an aperture, an ambient light illuminance detector to measure illuminance of ambient light, a projected image illuminance detector to measure illuminance of an image projected on the screen, an illuminance comparator to compare an illuminance detected by the ambient light illuminance detector and an illuminance detected by the projected image illuminance detector, and a diaphragm mechanism/image signal controller to control an intensity of image signals input into the display device and to control a size of an opening of the aperture of the diaphragm mechanism in accordance with a result of comparison by the illuminance comparator.

Abstract: The invention provides A lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis; and said aperture is shaped such that sides of the aperture curve inward approximately along lines that connect areas having substantially similar levels of contrast.

Abstract: The invention provides a lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis, and said aperture is substantially square.

Abstract: The invention provides a lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis, and said aperture is substantially triangular.

Abstract: The invention provides a projector having a light source, a display device to modulate light emitted from the light source, a lens device to project light emitted from the light source and modulated by the display device, wherein the lens device comprises a diaphragm mechanism, an image signal intensity detector to detect image signals input into the display device and to evaluate an intensity of the signals, a diaphragm mechanism drive control to drive the diaphragm mechanism so as to reduce the size of an aperture of the diaphragm mechanism when the image signal intensity detector ascertains that the intensity of the image signal is lower than a given level, and an image signal controller to increase the intensity of the image signal when the image signal intensity detector ascertains that the intensity of the image signal is lower than a given level.

Abstract: The invention provides a projector having a light source, a display device to modulate light emitted from the light source, a lens device to project light emitted from said light source via said display device, wherein the lens device has a diaphragm mechanism that is formed having an aperture, an object detector to detect an object between the lens device and the screen, and a diaphragm mechanism drive control to drive the diaphragm mechanism so as to reduce a size of an opening of the aperture of the diaphragm mechanism when the object detector detects an object between the lens device and the screen.

Abstract: The invention provides a lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis, and said aperture is substantially triangular.

Abstract: The invention provides a lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis, and said aperture is substantially trapezoidal.

Abstract: The invention provides A lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis; and said aperture is shaped such that sides of the aperture curve inward approximately along lines that connect areas having substantially similar levels of contrast.

Abstract: The invention provides a projector having a light source, a display device to modulate light emitted from the light source, a lens device to project light emitted from the light source and modulated by the display device, wherein the lens device comprises a diaphragm mechanism, an image signal intensity detector to detect image signals input into the display device and to evaluate an intensity of the signals, a diaphragm mechanism drive control to drive the diaphragm mechanism so as to reduce the size of an aperture of the diaphragm mechanism when the image signal intensity detector ascertains that the intensity of the image signal is lower than a given level, and an image signal controller to increase the intensity of the image signal when the image signal intensity detector ascertains that the intensity of the image signal is lower than a given level.

Abstract: The invention provides a lens device of a projector for projecting light that has been modulated and emitted by a display device, wherein said lens device has an optical axis and is arranged telecentric to rays of light emitted from said display device, said lens device has a diaphragm mechanism having an aperture at such a position that the lens device causes principal rays emitted from various locations on the display device to intersect with the optical axis, and said aperture is substantially square.

Abstract: The invention provides a projector having a light source, a display device to modulate light emitted from the light source, a lens device to project light emitted from said light source via said display device, wherein said lens device has a diaphragm mechanism formed having an aperture, an ambient light illuminance detector to measure illuminance of ambient light, a projected image illuminance detector to measure illuminance of an image projected on the screen, an illuminance comparator to compare an illuminance detected by said ambient light illuminance detector and an illuminance detected by said projected image illuminance detector, and a diaphragm mechanism/image signal controler to control an intensity of image signals input into the display device and to control a size of an opening of the aperture of the diaphragm mechanism in accordance with a result of comparison by the illuminance comparator.

Abstract: The invention provides a lens device and projector in which light passing through liquid crystal panels is projected on a screen using the lens device. The lens device includes a diaphragm mechanism. A telecentric optical system for the display device is provided between the diaphragm mechanism and the liquid crystal panels. An aperture of the diaphragm mechanism is positioned at a location where primary rays that are emitted from the liquid crystal panels parallel to an optical axis intersect with the optical axis. Contrast characteristics of the liquid crystal panels vary depending on angles and directions of incidence of rays of light. The aperture of the diaphragm mechanism is formed in a substantially triangular shape in accordance with the shape of the contrast characteristics.

Abstract: To ensure both telecentricity and a sufficiently high contrast, and to facilitate the improvement of performance characteristics of a projector that uses liquid crystal panels.

Abstract: A zoom lens focusing apparatus for a camera includes a zoom ring for adjusting a zoom lens section of the camera to different magnifications by moving a movable lens assembly therein forward and backward. A cam mechanism couples the zoom ring to the movable lens assembly, so that a change in the focal length of the zoom lens section caused by rotation of the zoom ring, is a logarithmic function of the angle of rotation of the zoom ring. A master lens section of the camera also has a movable lens assembly therein which is movable forward and backward by a driving device. The position of the zoom ring is detected while the movable lens of the zoom lens section moves backward or forward, and a sampling pulse generating circuit produces a pulse corresponding to the position of the zoom ring. A voltage which changes corresponding to the distance of the subject from the camera is applied to a charge-and-discharge circuit and the output thereof is held in a sample and hold circuit.