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: After the resist stripping liquid is supplied to the surface of the substrate which is being rotated at a first rotational speed, the rotational speed of the substrate is reduced from the first rotational speed to a second rotational speed with the supply of the resist stripping liquid to the surface of the substrate continued, thereby forming a liquid film by a mount of the resist stripping liquid on the surface of the substrate and then, maintaining a state where the liquid film is formed.

Abstract: A color combining optical system according to this invention aims at reducing the size of an optical system and suppressing the occurrence of color unevenness. According to this invention, there is provided a color combining optical system for combining color light reflected by a dichroic film and color light transmitted through the dichroic film. The optical thickness of the dichroic film increases or decreases from one end side to the other end side in the inclining direction of the dichroic film with respect to the incident optical axis of the color light reflected by the dichroic film.

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: 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: 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: 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: A method of manufacturing different types of image display apparatuses includes the steps of producing a lens barrel (housing) for holding optical elements, the lens barrel being commonly usable in the different types of image display apparatuses; selecting one type of image display apparatus to be manufactured among the different types of image display apparatuses; and manufacturing the one type of image display apparatus using the common lens barrel. In the image display apparatus manufactured by the method mentioned above, selective use of retainers for retaining the optical elements included in the illumination system, when arranging at least two different types of the illumination systems varying according to whether or not microlenses are provided, enables the different types of illumination systems to be easily constituted in accordance with the characteristics of image display elements varying according to whether or not microlenses are provided, and so on.

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 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: 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 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: 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: An image display apparatus includes a light source for supplying illumination light, a reflection type display device which reflects the illumination light and modulates the illumination light into image light, and an illumination optical system for guiding the illumination light to the reflection type display device. The illumination optical system includes a first optical member for directing the illumination light toward the reflection type display device, and a second optical member. The second optical member includes a part generating a secondary light source with the illumination light emitted from the light source, in which the light from the part emerges toward the first optical member, and a reflecting surface which guides illumination light which is not incident directly on the part to the part. In addition, a projection optical system guides the image light to an observer.

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: A color splitting/combining optical system is disclosed, which has a color-selective wave plate and a polarization splitting surface, and in which light leakage can be decreased when displayed in black. The 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, and a third optical member for color combining. Further, the optical system has a first color-selective wave plate and a second color-selective wave plate. The first color-selective wave plate converts the polarization direction of light in a first wavelength region by 90 degrees, and the second color-selective wave plate converts the polarization direction of light in the second wavelength region by 90 degrees. The optical system satisfies &lgr;1≠&lgr;2.

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 &dgr; is the phase difference of P-polarized light and S-polarized light at the polarization splitting film, the polarization splitting film satisfies the condition: 102°≦|&dgr;|≦180°.

Abstract: An actuator control device is provided for performing some modifications such as making the output of a disturbance observer zero for quickly restoring the proper tracking control if the out-of-track state takes place and if the outside force exceeding the maximum force generated by an actuator is applied to the device itself. In the actuator control device, a disturbance observer estimates disturbance added to the actuator. The second control signal corresponding to the estimated disturbance is added to the first control signal. The added signal is made to be a third control signal. Further, the second control signal is stored in a storage unit. The stored value is further added to the third control signal as the fifth control signal. By performing some modifications such as making the second control signal zero according to the abnormal state, this arrangement makes it possible to quickly restore the proper tracking control even if the out-of-track state takes place.

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.