Nikon Corporation

Mitsubishi Denki Kabushiki Kaisha

Panasonic Corporation

Tetsuo Hattori

Atsushi Sekine

Masaaki Kusano

Yuji Manabe

Kiyoshi Numazaki

Shunji Watanabe

Takamitsu Fujiu

Yoshiro Oikawa

Hiroshi Maki

Kazufumi Ishibashi

Toru Fujii

Tatsushi Nomura

Yoshinori Sango

Akira Tanaka

Mikio Okamoto

Sampei Esaki

Yasuhiro Iwaguchi

Shuichi Sugai

Tadaaki Nakamura

Hideaki Shimonura

Shingo Inoue

Tsuyoshi Matsumoto

Masatoshi Sato

Motoyuki Toki

Motoi Ueda

Kou Ohno

Kenichi Muramatsu

Hideaki Shimomura

Naotaka Shimamura

Kunihiko Yoshino

Tomoko Hattori, Legal Representative

Katsuhiko Katano

Takuya Shimbo

Nobuyuki Kikuchi

When a power switch is turned on, first and second analog switches are turned on while a third analog switch is turned off. Accordingly, at the time of starting, a forced excitation driving circuit supplies to a vibrator an oscillation output pulse which is substantially at the resonance frequency of the vibrator, thereby forcibly driving the vibrator in an excitation manner. Thereafter, when the vibrator substantially attains its stationary state and thereby the charged voltage of a capacitor reaches a threshold value of an inverter, the first and second analog switches are turned off while the third analog switch is turned on. Accordingly, the output of a self-excitation circuit is supplied to the electrode of the vibrator so as to vibrate the vibrator in a self-excitation manner.

Piezoelectric vibration angular velocity meter and camera using the same

A projection type display apparatus includes: a reflection type light valve; a polarization beam splitter that emits light obtained through polarization split executed thereat on light from a light source toward the reflection type light valve, analyzes light modulated at the reflection type light valve and includes a light blocking portion disposed near an outer edge of an exit surface through which the analyzed light exits; and a projection lens through which the analyzed light is projected.

Projection type display apparatus

A projection type display apparatus includes a color separation optical system separating light emitted from a light source into first, second and third color light; reflection type light valves provided each in correspondence to one of the first through third color light; polarization beam splitters provided each in correspondence to one of the first through third color light, which executes polarization separation causing the first through third color light to enter the reflection type light valves, and analyzing light exiting from the reflection type light valves after being modulated; a color composition optical system having a first, a second and a third prism, wherein the analyzed first through third color light undergo color composition; and a projection lens projecting the resulting light from the color composition, and lengths of optical paths wherein each of the first through third color light travels are equal to one another.

In a projection display apparatus that analyzes to pick up lights emitted from a plurality of the reflective light valves, color-composes the analyzed lights and projects the color-composed light, a dichroic film is disposed in at least one of optical paths of the respective color lights between the polarizing beam splitters and the dichroic prism. The dichroic film reflects such a component of a color light derived from the composite light incident on the projection optical system that has been reflected by a surface of a lens element constituting the projection optical system and incident on the dichroic prism after passing through a quarter wave phase plate and reflected or transmitted by the dichroic film within the dichroic prism to travel along the optical path of the color light in the reverse direction, thereby deflecting the color light component out of the optical path.

Projection display apparatus

A projection display apparatus in which a light emitted from a reflective light valve is made incident on a prism member and a light having passed through the prism member is projected by a projection lens, comprises a dust proofing cover that provides a seal between an emergence surface of the reflective light valve and an incidence surface of the prism member.

An analyzing-synthesizing optical system has the structure in which for each of the three primary colors of R, G, and B, there are provided a light valve for modulating incident light and a polarization beam splitter for guiding specific polarized light to this light valve and extracting only modulated light coming from the light valve to output it, wherein these light valves and polarization beam splitters are fixed as integrated with a synthesizing optical system comprising a cross dichroic prism and wherein optical path lengths of optical paths of the respective colors are adjusted to be almost equal to each other. A projection image display apparatus comprises the analyzing-synthesizing optical unit.

A projection type display device, having a light beam flux converting optical system which makes plural beam fluxes from light emitted from a light source and converts the each beam flux into a parallel beam flux and makes the each beam flux advance in a different direction, a polarized light separating color separating optical system which polarization separates and color separates light which was emitted from the light beam flux converting optical system, plural reflecting type light valves which modulate polarized light components emitted from the polarized light separating color separating optical system based on image information and a color synthesizing and analyzing optical system performing color synthesis and analysis of modulated light which were emitted from the plural reflecting type light valves.

Projection type display device

To suppress light loss without deteriorating resolution of a projected image, light is first polarized and separated by a polarizing beam splitter. Green light is separated from a light flux emitted by the polarizing beam splitter by a dichroic mirror having a green light reflection property. A light flux containing blue and red light, which is transmitted by the dichroic mirror, is separated into red light and blue light by a dichroic prism. Resultant color light is modulated and reflected by reflection light valves, returned to the corresponding dichroic mirror or dichroic prism, and combined by the dichroic mirror and the dichroic prism. Resultant combined color light is projected via the polarizing beam splitter and a projection lens. The dichroic prism transmits s-polarized light having wavelengths less than a wavelength substantially within a wavelength band of green light and reflects s-polarized light having larger wavelengths. The dichroic prism transmits p-polarized light having wavelengths less than a wavelength substantially within a wavelength band of green light and reflects p-polarized light having smaller wavelengths.

Color-projection apparatus operable to project a high-contrast image with minimal change in the state or phase of polarization of light flux

The projection type display apparatus according to the present invention has a prism for separating incident light into a plurality of light components and combining the plurality of modulated color components. The prism is constituted by a plurality of prism assemblies, each including an optical member made of an optically transparent material having a photoelastic constant whose absolute value is not greater than &plus;1.5&times;10 cm /N with respect to the incident light. More preferably, these plurality of prism assemblies are arranged such that each of a plurality of the separated color components is totally reflected by any of the prism assemblies.

Projection displays are disclosed that reduce the loss of image contrast due to angle-of-incidence and color dependencies of liquid crystal display panels, polarizing beamsplitters, and dichroic reflectors. The projection displays comprise an illumination source that provides a light flux that made uniform by an integrator. A color separation system then divides the light flux into red, green, and blue color components. The color-components are directed through field lenses to polarizing beamsplitters and then to liquid crystal light valves. The color components are reflected by the light valves back through the polarizing beamsplitters to a projection lens that forms an image. The projection lens is preferably telecentric. Field lenses are provided that direct substantially collimated color components to the liquid crystal light valves.

Projection displays with divergent chief rays at beam splitter

A cross dichroic prism comprises four triangular prisms having isosceles right triangular cross sections identical in shape, opposing side faces thereof being bonded and secured together with rectangular portions thereof facing each other; and a dichroic film having an X-shaped cross section formed between the bonding faces of the triangular prisms; wherein, of the four triangular prisms, a given prism and at least one of the prisms adjacent thereto have a refractive index difference therebetween of 0.00005 or less, and the remaining two prisms opposed thereto have a refractive index difference therebetween of 0.00005 or less.

Cross dichroic prism, method of making the same, and full-color projector using the same

A mirror comprises a transparent glass substrate and a dielectric multilayer film laminated on one surface (entrance surface) of the glass substrate. The dielectric multilayer film is formed by layers made of a high refractive index material and layers made of a low refractive index material which are alternately laminated, and is applied to a projection type display apparatus. The material and thickness of each layer are set so as to yield a polarization characteristic for causing reflected light to approach linearly polarized light.

Mirror and projection type display apparatus

The projection type display apparatus according to the present invention has a prism for separating incident light into a plurality of light components and combining the plurality of modulated color components. The prism is constituted by a plurality of prism assemblies, each including an optical member made of an optically transparent material having a photoelastic constant whose absolute value is not greater than &plus;1.5&times;10,cm,/N with respect to the incident light. More preferably, these plurality of prism assemblies are arranged such that each of a plurality of the separated color components is totally reflected by any of the prism assemblies.

Apparatus are disclosed that provide a high-luminance projected image with no color shading or uneven contrast. Light from a light source undergoes color separation by passing through a color-separation optical system (e.g., a cross-dichroic mirror or cross-dichroic prism). The light from the light source can also be split into first and second polarized lights by passage through, e.g., a first polarized-light beamsplitter (PBS). Each color-separated light is modulated by a respective color-signal light valve and undergoes color combining by, e.g., a cross-dichroic prism. The second polarized light, if formed, is modulated by a luminance-signal light valve, undergoes color combining and polarized-light combining by, e.g., a second PBS, and is projected by a projection lens (that comprises an aperture stop). The PBSs, cross-dichroic mirrors, and cross-dichroic prisms are situated where principal rays (defined by the aperture stop) are parallel to the optical axis. The first PBS (if present) and color-separation optical system are preferably arranged between a front illumination lens group and a rear illumination lens group both comprising an illumination relay optical system telecentric on both front and rear sides thereof. Field lenses and relay lenses can be included that comprise a relay optical system forming a magnified image of the color-signal light valves at a position conjugate to the luminance-signal light valve with respect to the projection lens.

Growing community of inventors

Yokohama, Japan

Tetsuo Hattori