Abstract: A color combining optical system is disclosed, with which light of a plurality of colors can be combined while reducing the loss of light due to fluctuations in the incidence angle on a polarization color combining film. The color combining optical system, which combines a first color light and a second color light, includes a polarization color combining film made of a multilayer film. The polarization color combining film combines a first polarization component of the first color light and a second polarization component of the second color light, which has a polarization direction substantially perpendicular to the first polarization component, with an efficiency of 90% or more in a predetermined incidence angle range.

Abstract: An image display apparatus disclosed includes:

Abstract: A display apparatus of the type which forms a color image by modulating a plurality of lights different from each other in color by one or a plurality of display elements, includes a device for changing the color purity of at least one of the plurality of lights by inserting or extracting a wavelength selection element into or out of the optical path of at least one of the plurality of lights or changing the attitude of the wavelength selection element, and a device for supplying information as to whether the wavelength selection element is in the optical path of the at least one color light or information on the attitude of the wavelength selection element in the optical path of the at least one color light.

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 the head and positioning the 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 a wait mode, the positioning operation of the micro actuator is stopped.

Abstract: An information recording/reproducing system in which a host system making access to a magnetic disk apparatus can be limited to a specific one. A magnetic disk apparatus includes an authentication key generating block for generating an authentication key on the basis of physical characteristic(s) of the magnetic disk apparatus itself. The magnetic disk apparatus and the host system have, respectively, authentication key recording block for recording the authentication key and authentication data generating block for generating authentication data on the basis of the authentication key. Access from the host system to information of the magnetic disk apparatus is controlled based on the authentication data of the host system and the authentication data of the magnetic disk apparatus.

Abstract: A magnetic disk apparatus includes a requesting unit for requesting the magnetic disk apparatus to re-set a value of specification information capable of determining performance of the magnetic disk apparatus in combination with either identification result or flag information; a performance unit for causing the magnetic disk apparatus which receives the request to re-set the own specification; a detecting unit for detecting an internal condition of the disk apparatus; a processing unit for processing the detection result; a conversion unit for converting the internal condition of the magnetic disk apparatus into states of a numeral value, a figure, a color, and a sound in combination with the process result, and for notifying the converted condition to a user; and a battery.

Abstract: In a positioning control device for a two-stage actuator having a coarse-movement actuator and a fine-movement actuator, a notch filter having a cutoff frequency fn is provided to a coarse-movement control loop, and the fine-movement actuator is driven by a sine wave of the frequency fn. At the frequency fn, a head position signal becomes identical with an output signal of the fine-movement actuator, by which the gain of the fine-movement actuator can be estimated by an adaptive identification unit with high accuracy based on the control input to the fine-movement actuator and the head position signal.

Abstract: An image display apparatus includes a light source for emitting illumination light, an image display element for displaying an image by reflecting incident light, an illumination optical element which reflects the illumination light from the light source toward the image display element and through which image light from the image display element is transmitted, an observation optical element for guiding the image light transmitted through the illumination optical element to an eye of an observer, and a light-shielding member for blocking at least one of unnecessary light which is contained in the illumination light from the light source and travels outside an effective image display area of the image display element and unnecessary light which is contained in the image light from the image display element and travels outside an effective observation space.

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: An image display apparatus includes: a color separation optical system having a color separation optical member for reflecting a color light component in a specific wavelength range of the converging light and transmitting color light components in the other wavelength ranges. An optical axis of light incident on the color separation optical member forms an angle smaller than 45 degrees with a normal to a light incident surface of the color separation optical member.

Abstract: In a projection apparatus, an optical integrator is illuminated with light from a light source, one or more image display elements is irradiated with a plurality of beams from the integrator, and image light from the image display element or elements is projected by a projection optical system. The illuminating range of some of the plurality of beams is made smaller than the illuminating range of the other beams.

Abstract: In an illuminating device in which a light from a light source is separated into three color lights differing in optical path from one another by a color separating system, and light modulating elements conforming to the respective color lights are illuminated with the color lights, at least one of the optical paths of the three color lights has therein a reflecting system having positive power for reflecting the color light passing therethrough.

Abstract: There is disclosed a display apparatus including a polarizing beam splitter for splitting light from a light source, a reflective liquid crystal display element illuminated by light of a predetermined polarizing direction through the polarizing beam splitter, and a double refractive phase compensation element arranged between the polarizing beam splitter and the reflective liquid crystal display element.

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: In an image observation apparatus, image light is guided to an observer's eye by using a first refractive surface on which the image light from an image display device is made incident, a reflective surface for reflecting the image light made incident from the first refractive surface, and an optical element having a second refractive surface for emitting the image light reflected from the reflective surface. A diffraction optical part is provided in front of the reflective surface of the optical element.

Abstract: When light from a reflection image display element is incident on a polarization split surface at an angle other than 45°, leakage light that decreases the contrast of an image is produced.

Abstract: In a projection type image display apparatus, when the angle of light incident on the multi-layer film of a polarizing beam splitter for synthesizing an optical path becomes uneven, the loss of the light occurs.

Abstract: An image display apparatus includes a light source for supplying illumination light, a reflection type display element for modulating the illumination light into image light by reflecting the light, an illumination optical system for guiding the illumination light to the reflection type display element, and a projection optical system for guiding the image light to an observer. The image light is incident on the projection optical system via at least a portion of said illumination optical system. The projection optical system includes a member for correcting an optical path length difference between rays of the image light caused when the image light is incident on the projection optical system via at least a portion of the illumination optical system.

Abstract: An image display optical system according to the present invention has an illumination optical system, a plurality of image display elements, a color separation/combination optical system, and a projection optical system. The image display optical system also has a light guide element which reflects illumination light from the illumination optical system with a reflectivity of substantially 100% to guide the reflected light to the color separation/combination optical system and transmits image light from the color separation/combination optical system to the projection optical system.

Abstract: There is provided a color separating-combining optical system having: