Canon Kabushiki Kaisha

Mitsumi Electric Company Ltd.

Hitachi-johnson Controls Air Conditioning, Inc.

Atsushi Okuyama

Hiroyuki Kodama

Masayuki Abe

Takashi Sudo

Saburo Sugawara

Junko Kuramochi

Tatsuo Chigira

Yu Yamauchi

Ken Wada

Shoichi Yamazaki

Shuichi Kobayashi

Masahiro Tamura

Makoto Takahashi

Hideo Yokota

Keiji Ohtaka

Yoshiaki Sato

Kenji Tamura

Akihiro Ouchi

Noriyuki Kobayashi

Kenichi Kimura

Reona Ushigome

Toshiki Ishino

Takuji Umezu

Katsumi Azusawa

Ryota Kadowaki

Makoto Matsuura

Shouichi Yamazaki

Tsutomu Kurokawa

Keiji Otaka

Koji Tsukii

Hiroyuki Okuda

A DC power supply unit is provided that allows for improving efficiency and reducing harmonic currents. A DC power supply unit includes: a bridge rectification circuit having diodes and MOSFETs; a reactor that is arranged between the AC power supply and the bridge rectifier circuit; a smoothing capacitor that is connected to an output side of the bridge rectifier circuit and smoothes a voltage; and a converter control unit that executes, based on predetermined threshold values, a diode rectification control that uses diodes and parasitic diodes of the MOSFETs, a synchronous rectification control that switches the MOSFETs in synchronization with a polarity of the voltage of the AC power supply, a partial switching control that repeats partially short-circuiting the reactor multiple times in a half cycle of the AC power supply, or a fast switching control that short-circuits the reactor at a predetermined frequency over a full AC cycle.

DC power supply unit and air conditioner using same

A lens holder driving device includes a lens holder in which a lens assembly is mounted, a driving coil fixed to the lens holder at outside circumference thereof, a magnet opposite to the driving coil, a yoke including the magnet, an elastic member supporting the lens holder in a direction of an optical axis shiftably, and a base disposed at a lower side of the lens holder. The yoke includes an outer yoke including the magnet at an inner wall surface thereof. The elastic member includes an upper elastic member disposed at an upper side of the lens holder. The upper elastic member is mounted to the inner wall of the outer yoke in a state where the upper elastic member is positioned and fitted to a spacer.

Lens holder driving device capable of easily mounting upper elastic member to outer yoke

An image pickup apparatus includes an image sensor that includes a plurality of first photoelectric conversion elements, and a plurality of second photoelectric conversion elements, a plurality of micro lenses each of which is provided for each pixel on the image sensor, and a controller configured to execute still image pickup using the plurality of second photoelectric conversion elements simultaneous with motion image pickup using the plurality of first photoelectric conversion elements. Each micro lens introduces a light flux from part of an exit pupil of the image pickup optical system to at least one first photoelectric conversion element, and a light flux from another part of the exit pupil to at least one second photoelectric conversion element.

Image pickup apparatus

The wavelength-selective polarization conversion element includes a plurality of polarization splitting surfaces each of which separates entering light into two polarized light components having polarization directions different from each other, a plurality of phase plates that causes a polarization direction of one polarized light component in the two polarized light components from the polarization splitting surfaces to coincide with a polarization direction of the other polarized light component. The element further includes a plurality of dichroic surfaces that is disposed closer to a light entrance side than the plurality of polarization splitting surfaces or between the plurality of polarization splitting surfaces and the plurality of phase plates, each dichroic surface separating entering light into two wavelength region components different from each other. The element is capable of generating light components having different polarization directions and different wavelength regions from non-polarized light while preventing a reduction of light use efficiency.

Wavelength-selective polarization conversion element for generating two light components having polarization directions and wavelength regions different from each other, illumination optical system, and image projection apparatus including the element

An optical system for image projection is disclosed which is capable of improving contrast while suppressing reduction of light amount. The optical system includes a converging optical system, and a polarization beam splitting surface transmitting an incoming light flux having a first polarization direction from the converging optical system, to introduce it to the image-forming element and causing light having a second polarization direction, of an outgoing light flux from the image-forming element, to proceed to a projection optical system. In a first cross-section parallel to a normal to the polarization beam splitting surface, the converging optical system has a configuration causing an incident angle on the splitting surface of a light ray passing through a barycenter of intensity distribution of the outgoing light flux to be larger than an incident angle thereon of a light ray passing through a barycenter of intensity distribution of the incoming light flux.

Optical system for image projection and image projection apparatus including a polarization beam splitting surface

An optical system for image projection is disclosed which is easy to be manufactured and designed and capable of projecting a bright image with high contrast. The optical system includes an illumination optical system introducing a luminous flux emitted from a light source to an image-forming element through an optical surface having a light-splitting function, and a projection optical system projecting the luminous flux from the image-forming element through the optical surface onto a projection surface. The illumination optical system includes a conversion system which respectively converts the widths of the luminous flux in first and second cross-sections into widths different from those before entering thereinto. Conversion rates in the first and second cross-sections are different from each other.

Illumination optical system including luminous flux conversion system

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 &#x3b8;x&#x3c;&#x3b8;y and 0&#xb0;&#x3c;&#x3c6;y&#x3c;&#x3b8;y. &#x3b8;x and &#x3b8;y represent the maximum incident angles onto the surface in the x and y directions, and &#x3c6;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.

Illumination optical system and image projection apparatus

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.

Wavelength-selective polarization conversion element, projection displaying optical system and image projection apparatus

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 1/4 wave plate provided on an optical path of the red light, a second 1/4 wave plate provided on an optical path of the green light, and a third 1/4 wave plate provided on an optical path of the blue light, a direction of a fast axis of the third 1/4 wave plate being different from a direction that minimizes leakage light of the blue light.

Image projection apparatus and adjusting method used for the same

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 &#x3b1;&#xd7;E&#x3c;6000000 and K&#x3e;0.5, where &#x3b1; is a coefficient of linear expansion of the first and second glass members (10/K), E is a Young's modulus of the first and second glass members (10N/mm), and K is a photoelastic constant of the first and second glass members (nm/mm&#xb7;mm/N).

Polarization splitter, optical unit and image projector

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. Each optical path of the illumination light and each optical path of the image light are different from each other in the light guide element and the color separation/combination optical system. The projection optical system is an eccentric optical system. With the configuration, the use efficiency of light can be enhanced to obtain bright and high-definition display images.

Image display optical system and projection type image display apparatus

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.

Image projection apparatus and image projection system

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 &#xbc; phase plate disposed between the polarization beam splitter and the liquid crystal display element. In addition, the phase difference &#x3c6; that the &#xbc; phase plate gives to the ray made incident into the &#xbc; phase plate at an angle &#x3b8; satisfies:&#x3c0;/2&#xd7;0.8&#x3c;&#x3c6;&#x3c;&#x3c0;/2&#xd7;1.2.

Image display apparatus having particular phase difference

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.

Color separating optical system, image display optical system, and projection image display apparatus

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 &#x3bb;, where &#x3bb;and &#x3bb;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%.

Growing community of inventors

Tokorozawa, Japan

Atsushi Okuyama