Abstract: The present invention provides a display apparatus which can prevent the unevenness of the quantity of light in case of display giving priority to color reproducibility and can also correct the unevenness of the up rate to the brightness in display attaching importance to color reproducibility in case of display giving priority to brightness. In the display apparatus, light from a light source 1 is separated into three colors R, G and B by dichroic mirrors DM1, DM2, and liquid crystal display elements 8R, 8G and 8B corresponding to the color-separated three colors are illuminated with these lights, and the three color lights are modulated by these display elements to thereby form a color image, and the dichroic mirrors DM1 and DM2 include a dichroic mirror DM1 subjected to inclination correction movable in its inclined direction.

Abstract: In a cross dichroic prism wherein four square pillar prisms of which the total of the angles including the prism ridge lines is 360° are joined together with the prism ridge lines thereof made coincident with one another and prism sides forming the respective prism ridge lines are joined together so that the joined surface thereof may become two planes intersecting with each other, and dichroic film is provided on the joined surface, when the lengths of perpendiculars from a point on the prism ridge line to the non-joined surfaces of the respective square pillar prisms are defined as L1, L2, L3 and L4, L1≠L2=L3=L4 is satisfied.

Abstract: An image viewing apparatus has a stop for limiting light from an original image, and a viewing optical system for guiding the light from the original image, limited by the stop, to the eye of a viewer. The viewing optical system has a prism body including an entrance surface into which the light from the original image is incident, a reflecting surface for reflecting the incident light, and an exit surface from which the reflected light emerges. At least one of the entrance surface, reflecting surface, and exit surface is a curved surface, which is a rotationally asymmetric, aspherical surface. The apparatus satisfies the following condition: 3.

Abstract: An optical system having a first optical acting surface and a second optical acting surface in an optical path between a focal plane and a stop. In the optical path traced from the focal plane to the stop, light emitted from the focal plane is reflected by the second optical acting surface and thereafter reflected by the first optical acting surface to reach the stop. A ray connecting a center of the focal plane with a center of the stop via the first optical acting surface and the second optical acting surface is defined as a reference axis ray. The second optical acting surface is of a rotationally asymmetric, aspherical shape only one symmetry plane of which is a plane including the reference axis ray.

Abstract: This invention provides a liquid crystal display apparatus which can reduce thermal load on a polarizing plate or display element, decrease the number of components necessary for reducing the thermal load on the polarizing plate, and reduce cost by decreasing the power consumption of a cooling fan. The display apparatus has a unit for changing the color purity of at least one of a puerility of colors. A polarizing plate in the optical path of light whose color purity is changed by the color purity changing unit is formed from a heat-transfer transparent substrate having a thermal conductivity of 1.2 W/(m·K) or more.

Abstract: This specification discloses an illuminating apparatus having a condensing optical system for converting light from a light source into convergent light, a first convex lens array for receiving the convergent light, a collimating optical system for making a plurality of light beams from the first convex lens array parallel to one another, and a polarization converting element array for individually converting the plurality of light beams from the collimating optical system into polarized lights.

Abstract: A projection apparatus which is provided with a light source, a dichroic mirror for separating a light from the light source in a plurality of color lights, a display panel disposed on the optical path of each of the color lights, a first dichroic mirror for combining two color lights in the display panel illuminated with each of the color lights, a second dichroic mirror for combining and emitting the color lights emitted and combined by the first dichroic mirror and the other color lights, first and second optical units each disposed for the respective color light entering the second dichroic mirror for making the lights telecentric; and a projection lens for projecting the lights emitted and combined by the second dichroic mirror, and which is compact and suffers little from the distortion of optical performance, and particularly of an image.

Abstract: An illuminating apparatus includes a condensing optical system for converting light from a light source into convergent light, and a first convex lens array for receiving the convergent light, and a collimating optical system for making a plurality of light beams from the first convex lens array parallel to one another. In addition, a polarization converting element array individually converts the plurality of light beams from the collimating optical system into polarized lights.

Abstract: A magnetic disk device comprises at least a disk having information, at least a head for reading or writing information from or into the disk, at least a micro actuator for supporting said head and positioning said head, a coarse actuator for carrying the micro actuator and positioning the head, a controller for controlling the micro actuator and the coarse actuator based on the servo information read by the head, and a host controller for determining that information is to be read. In the case where the host controller determines that the operation is in wait mode, the positioning operation of the micro actuator is stopped.

Abstract: In a light irradiating apparatus, a first fly-eye lens and a second fly-eye lens are disposed in succession from a light source side. A first lens having negative refractive power is disposed more adjacent to the light source side than the first fly-eye lens. A second lens having positive refractive power is disposed more adjacent to the light source side than the second fly-eye lens. The specification also discloses an image projecting apparatus for illuminating an image display element by the light emerging from the light irradiating apparatus, and projecting an image displayed on the image display element.

Abstract: A projection type display apparatus is arranged to be able to implement both brightness-priority display and color-reproduction-priority display by itself. In the display apparatus, white light from a light source 1 is separated into beams of three colors by a color separation optical system comprised of a combination of dichroic mirrors DM1, DM2, total reflection mirrors M1, M2, M3, etc., and the beams of the three colors are made incident to liquid-crystal display units 8R, 8G, 8B. After that, the beams are combined by a dichroic prism 9 and images of the liquid-crystal display units 8R, 8G, 8B are projected by a projection lens 10. In this display apparatus, a dichroic filter DF for transmitting light in a region not less than a certain wavelength (for example, about 600 nm) but intercepting light in the other region is arranged so as to be able to be put into or out of an optical path immediately before the liquid-crystal display unit 8R.

Abstract: An optical low-pass filter comprises a phase advancing area which advances a phase of a wavefront of an incident pencil of rays with respect to a phase of a wavefront of a center of the incident pencil of rays, and a phase retarding area which retards the phase of the wavefront of the incident pencil of rays with respect to the phase of the wavefront of the center of the incident pencil of rays, the phase advancing area and the phase retarding area alternately existing in the optical low-pass filter, and an optical apparatus comprises an image forming optical system, an image pickup element, and such an optical low-pass filter.

Abstract: An optical member used in a color composition system of an optical instrument, such as a projector, includesa prism member formed by joining a plurality of prisms, and a plurality of image forming units fixed to the prism member, wherein joint surfaces of the plurality of prisms reflect therefrom light of a predetermined wavelength range and pass therethrough the light other than that of the predetermined wavelength range, and wherein relative positions of the plurality of prisms are shifted along the joint surfaces to adjust optical path length of the light emitting from each of the image forming units and passing through the prism member, and thereafter the plurality of prisms are fixed.

Abstract: An image observing apparatus according to the present invention includes: an optical element including a first face inclined relative to an observer, a second face composed of a reflective concave side, and a third face which the light from the image enters so as to have overall a positive refractive power; a line-of-sight detecting device for detecting a line of sight of the observer including a light source to illuminate a fore eye portion of the observer and a light receiving device for receiving an image of the fore eye portion; and a light reflecting device, provided in an observing side of the first face, for reflecting the light emanating from the light source. In this image observing apparatus, the light from the image entering the third face is reflected by the first face, is condenser-reflected at a first face side by the second face, and is irradiated from the first face.

Abstract: The present invention relates to an optical system apparatus, which has a first surface symmetric with respect to only one symmetry plane and a second surface symmetric with respect to only the symmetry plane, in which the first plane is a reflective, concave surface and is inclined relative to a reference axial ray present in the symmetry plane. Further, a local power of the second surface changes from a positive to a negative.

Abstract: The present invention relates to an image observation apparatus which comprises an optical system having a plurality of reflecting surfaces and a positive refracting power to guide light from an image to an observer and a visual axis detection system including a light source for illuminating an anterior ocular segment of the observer to detect a visual axis of the observer, a light-receiving device for receiving an image of the anterior ocular segment which is formed by light reflected by the anterior ocular segment and having passed through a portion of the optical system, and a device for correcting an aberration of the image of the anterior ocular segment which occurs when the image passes through at least a portion of the optical system.

Abstract: A projection apparatus in which in order that an original image, which is compressed in a horizontal direction, may be projected onto a screen at a predetermined location by a master lens, the original image is disposed with the center thereof deviated relative to the optical axis of the master lens and in which an anamorphic lens having an optical axis inclined with respect to the optical axis of the master lens and having refractive power in a horizontal direction is disposed on the screen side of the master lens.

Abstract: A positioning system of an optical disc apparatus includes focus error detecting part for detecting a focus error signal as a focal shift of a light spot related to an information recording surface of an optical disc, light spot moving part in the direction intersecting substantially perpendicularly to the optical disc surface, first digital arithmetic part for receiving the focus error signal and outputting a first control signal, second digital arithmetic part for receiving the focus error signal and a specified third control signal, performing arithmetic operations of a disturbance observer and outputting a second control signal, adding circuit for adding the first control signal and the second control signal and outputting the third control signal, drive circuit for driving the light spot moving part in a direction intersecting perpendicularly to the disc surface by the third control signal, wherein the first and the second digital arithmetic circuit perform arithmetic operations at different sampling per

Abstract: A zoom lens of the rear focus type is disclosed, comprising first, second, third and fourth lens units of positive, negative, positive and positive refractive powers in this order from the object side, zooming from the wide-angle end to the telephoto end being performed by moving the second lens unit toward the image side, compensation for the image shift and focusing being performed by moving the fourth lens unit, and the zoom lens satisfying the following conditions:2.2<.vertline.Fb/FW.vertline.0.8<.vertline.Fb/f3,4.vertline.<1.1where Fb is a back focal distance in the wide-angle end, FW is the shortest focal length of the entire lens system, and f3,4 is a composite focal length of the third and fourth lens units.