Abstract: The image projection apparatus includes a first, a second and a third reflective liquid crystal display element, an illumination optical system which color-separates light from a light source into first, second and third color light component and illuminating the three reflective liquid crystal display elements with the respective color light components, a projection optical system combining the color light components emerged from the three reflective liquid crystal display elements and projecting the combined color light components onto a projection surface, and an incidence side polarizing plate arranged between the light source and at least one of the three reflective liquid crystal display elements. An average value of a transmittance, in a wavelength region of 450 nm to 630 nm, of the incidence side polarizing plate for light of a polarization direction to be blocked thereby is 5% or less.

Abstract: An illumination optical system is disclosed which capable of uniformly illuminating a surface to be illuminated. The illumination optical system comprises a polarization conversion element which converts a luminous flux from a light source into a luminous flux having a certain polarization direction, a polarization beam splitter which splits the luminous flux from the polarization conversion element, and a phase plate which gives a phase difference to the luminous flux from the polarization beam splitter. The system illuminates the surface with the luminous flux from the phase plate and satisfies the conditions ?x<?y and 0°<?y<?y. ?x and ?y represent the maximum incident angles onto the surface in the x and y directions, and ?y represents an incident angle onto the phase plate at which the phase difference at a principal wavelength of the luminous flux that passes through the phase plate is 90 degrees.

Abstract: A wavelength-selective polarization conversion element is disclosed, which is capable of reducing the number of optical elements in an optical system and simplifying the configuration thereof. The polarization conversion element comprises a beam splitting film which splits light by transmission and reflection and has a characteristic in which at least its transmittance for light with a first polarization direction changes between a transmittance higher than 50% and a transmittance lower than 50% depending on wavelength regions, and a phase plate which converts the polarization direction of light from the beam splitting film between the first polarization direction and a second polarization direction. The polarization conversion element converts light of two of first, second and third wavelength regions into light with one of the first and second polarization directions and converts light of the remaining wavelength region into light with the other polarization direction.

Abstract: An image display apparatus is disclosed which is capable of obtaining a projected image having high contrast. The image display apparatus includes a luminous flux dividing system dividing light from a light source into a plurality of luminous fluxes and a condensing optical system leading the luminous fluxes emerged from the luminous flux dividing system to a reflective liquid crystal display element. The condensing optical system includes a condenser lens, a field lens making light from the condenser lens substantially telecentric, a polarization beam splitter, and a ¼ phase plate disposed between the polarization beam splitter and the liquid crystal display element. In addition, the phase difference ? that the ¼ phase plate gives to the ray made incident into the ¼ phase plate at an angle ? satisfies: ?/2×0.8<?<?/2×1.2.

Abstract: A color separating-combining optical system is configured to separate illumination light into a plurality of color spectrums, guiding these color spectrums to respective image display elements, and combining the color spectrums modulated by the image display elements. The system includes a first polarization separating optical system that reflects the first color spectrum from the separating optical system to a first image display element and transmits the first color spectrum from the first image display element to the combining optical system. Similarly, a second polarization separating optical system is provided that reflects and transmits the second color spectrum. The degree of linear polarization of a reflected color can be maintained higher than that of another, and/or an antireflection element can be included in the path of reflected light.

Abstract: In a magnetic disk device, oscillation occurring at a frequency higher than Nyquist frequency is suppressed. In one embodiment, a multi-late filter having a resonance point at a frequency higher than the intended Nyquist frequency is introduced in a previous stage of a controlled object. At that time, since a resonance characteristic of the multi-rate filter is aliased by a sampler, the multi-rate filter is designed such that the resonance point after the aliasing is stabilized in phase by a following compensator.

Abstract: A color splitting/combining optical system includes a first optical member for color splitting and a second optical member which has a polarization splitting surface for color splitting/combining, a third optical member for color combining a first color-selective wave plates and a second color-selective wave plate. The first and second color-selective wave plates convert the polarization direction of light in a first and second wavelength regions respectively by 90 degrees. The optical system satisfies ?1??2, where ?1 and ?2 represent wavelengths in which the ratio of the light component having the polarization direction converted by 90 degrees by the first and second color-selective wave plates respectively become substantially 50%.

Abstract: In one embodiment, the magnetic disk drive has a magnetic head, an actuator driving the magnetic head, and a control portion controlling a controlled object, including the magnetic head and the actuator, by creating a control signal based on a given target position signal and on a position signal played back by the magnetic head such that the magnetic head reaches a target position.

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 display apparatus is constructed to make a plurality of light beams of mutually different colors incident to a display element and modulate the beams of the respective colors by the display element to form images of the respective colors. Purity of a predetermined color out of the colors is variable and a control pattern of the image display element is modified according to variation in the purity of the predetermined color.

Abstract: An illumination optical system that illuminates a plurality of image display elements comprises; a color separating optical system that separates light emitted from a light source into a plurality of color light components; and a plurality of light-guiding optical systems, each of which guides light component to a corresponding one of the plurality of image display elements. An illumination area on the image display element that is illuminated by at least one of the plurality of light-guiding optical systems is larger than those on the image display elements illuminated by the other ones of the plurality of light-guiding optical systems. This provides a compact projection type image display apparatus which can project bright images.

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 more display elements, includes a device for changing the color purity of at least one light 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: Conventionally, concentrated illumination of a central portion of an image (about 40-60% of the whole image) in which information such as letters and a picture tends to concentrate (centrally concentrated illumination) and uniform illumination of the whole image (uniform illumination) can be carried out by using two separate apparatuses, but no single conventional image display apparatus can carry out both of the two types of illumination. Accordingly, an object of the present invention is to provide a liquid crystal display apparatus which can carry out centrally concentrated illumination, uniform illumination, and various other illumination states (illumination distributions). According to the present invention, an image display apparatus (such as a liquid crystal projector) is structured such that a fly-eye lens or a part thereof in an illumination optical system for illuminating an image forming element is moved to vary the illumination distribution on the image forming element.

Abstract: An image projection apparatus includes a first reflection type liquid crystal display device for modulating and reflecting red light, a second reflection type liquid crystal display device for modulating and reflecting green light, a third reflection type liquid crystal display device for modulating and reflecting blue light, the image projection apparatus projecting colored light made of the red, green and blue lights from the first to third reflection type liquid crystal display devices, a first ¼ wave plate provided on an optical path of the red light, a second ¼ wave plate provided on an optical path of the green light, and a third ¼ wave plate provided on an optical path of the blue light, a direction of a fast axis of the third ¼ wave plate being different from a direction that minimizes leakage light of the blue light.

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: A polarization beam splitting optical system is disclosed which reduces components of the P-polarization direction that are contained in polarized light that is analyzed upon being incident on a polarization splitting film in an inclined manner with respect to an optical axis of an optical system. This optical system includes a polarization splitting film, which guides polarized light from a first optical system to a reflection type image display element and then analyzes and guides polarized light from the image display element to a projection optical system. When ? is the phase difference of P-polarized light and S-polarized light at the polarization splitting film, the polarization splitting film satisfies the condition: 120°?|?|?180°.

Abstract: An image display apparatus discloed includes a condensing optical system changing illumination light from a light source converging light; separation optical system having separation optical member reflecting color light component in specific wavelength range of the converging light and transmitting color light components the other wavelength ranges; a plurality of image display devices illuminated by a plurality of color flight components separated by the color separation optical system, respectively, color combination optical system image light components from the plurality of image plurality combining colors emanating and display devices; projection optical system for projecting image light components combined by the color combination optical system on surface on which projection is performed, light incident color separation optical member forms an angle smaller than 45 degrees with a normal to light incident surface of the color separation optical member.

Abstract: A color combining optical system which can suppress occurrence of a thermal problem and increase in size is disclosed. The color combining optical system comprises a first optical element which has a first optical film reflecting light having a first polarizing direction and transmitting light in a second polarizing direction and combines the first and second color lights by the first optical film. In addition, the optical system comprises a polarizing plate which analyzes a third color light. Furthermore, the optical system comprises a second optical element which combines, by a second optical film, the third color light transmitted through the polarizing plate with the first and second color lights combined by the first optical element.

Abstract: A post-dry etching cleaning liquid composition for cleaning a substrate after dry etching is provided, the cleaning liquid composition containing at least one type of fluorine compound, glyoxylic acid, at least one type of organic acid salt, and water. With regard to the fluorine compound, ammonium fluoride may be used. With regard to the organic acid salt, at least one of ammonium oxalate, ammonium tartarate, ammonium citrate, and ammonium acetate may be used.

Abstract: A polarization splitter includes first and second glass members, and a polarization splitting layer and an adhesive layer arranged between the first and second glass members, wherein the polarization splitter satisfies ?2×E<6000000 and K>0.5, where ? is a coefficient of linear expansion of the first and second glass members (10?7/K), E is a Young's modulus of the first and second glass members (108 N/mm2), and K is a photoelastic constant of the first and second glass members (nm/mm·mm2/N).