Hitachi, Ltd.

Shigeru Inaoka

Koji Hirata

Shigeru Mori

Kazunari Nakagawa

Masahiko Yatsu

Mikio Shiraishi

Naoyuki Ogura

Hiroki Yoshikawa

Yasuo Otsuka

Toru Numata

Masayuki Muranaka

Isao Yoshizaki

Takahiko Yoshida

Kiyoshi Wada

Tooru Numata

Kyohei Fukuda

Hiroshi Jitsukata

Yoji Nakayama

A screen for use in a projection-type image display apparatus having an image displaying element which includes a plurality of pixels for modulating light from a light source so as to form an enlarged picture on the screen. The screen includes a Fresnel lens sheet, a first sheet disposed on the light emission side of the Fresnel lens sheet, and a second sheet disposed on a light emission side of the first sheet. The first sheet includes a plurality of lenticular lenses which extend in a longitudinal direction and are arranged in a horizontal direction, with light passing window portions being formed at positions opposing the lenticular lenses and with light absorbing portions provided therebetween.

Projection-type picture display apparatus and screen used thereby

A screen for use in a projection-type image display apparatus having an image displaying element which includes a plurality of pixels for modulating light from a light source so as to form an enlarged picture on the screen. The screen includes a Fresnel lens sheet having Fresnel lenses on a light emission side, a first sheet disposed on the light emission side of the Fresnel lens sheet, and a second sheet disposed on a light emission side of the first sheet and adhered thereto. The first sheet includes a plurality of lenticular lenses formed on a light incident side which extend in a longitudinal direction and are arranged in a horizontal direction, with light passing window portions being formed at positions opposing the lenticular lenses and with light absorbing portions provided therebetween. The second sheet includes a light scattering element therein.

A screen for allowing light generated by a light source and modulated by a picture display device having pixels laid out to form a matrix to produce an image thereon to be projected on the screen as an enlarged picture. The screen has a Fresnel lens sheet forming Fresnel lenses at an emission side, a first member for receiving light emitted from the Fresnel lens sheet having light passing windows, and a plurality of light absorbing layers and a second member placed on the emission side of the first member. A pitch of the light absorbing layers is made smaller than a pitch in a first direction of pixels projected and enlarged on the screen, and a pitch in a second direction of the pixels is at least twice of a pitch of the Fresnel lenses.

For obtaining both high brightness under condition of small-sized and simplified structure and suppression of increase in temperature of liquid crystal display elements and polarizing elements, in a liquid crystal display apparatus, comprising: a liquid crystal display element for converting light from a light source into display picture depending on a driving signal; an optical projection system containing a first optical element and for projecting said light signal toward an object of projection; exit side polarizing elements ; a holding member for holding them with the liquid crystal display element ; and cooling medium incident side polarizing elements , wherein, a space is defined by either one of the incident side polarizing elements and the liquid crystal display element , the first optical element , between the liquid crystal display element and the first optical element , and the holding member , and said space is filled up with the cooling medium

Liquid crystal display apparatus and optical device for use therein

A projection optical system is used for projecting a light generated by a light source and modulated by a picture display device comprising pixels laid out to form a matrix on a screen as an enlarged picture. The screen is provided with a Fresnel lens sheet placed on an emission side of the picture display device, a first configuration element and a light passing plate fixed on the emission side of the first configuration element. The first configuration element has lenticular lenses and light absorbing layers. The lenticular lenses are provided on an incidence side of a light passing through the Fresnel lens sheet. The light absorbing layers are each provided at a place in close proximity to the focal point of one of the lenticular lenses and are separated from each other by a predetermined distance for forming light passing windows.

For obtaining both high brightness under condition of small-sized and simplified structure and suppression of increase in temperature of liquid crystal display elements and polarizing elements, in a liquid crystal display apparatus, comprising: a liquid crystal display element for converting light from a light source into display picture depending on a driving signal; an optical projection system containing a first optical element and for projecting said light signal toward an object of projection; exit side polarizing elements ; a holding member for holding them with the liquid crystal display element ; and cooling medium ; incident side polarizing elements , wherein, a space is defined by either one of the incident side polarizing elements and the liquid crystal display element , the first optical element , between the liquid crystal display element and the first optical element , and the holding member , and said space is filled up with the cooling medium

Liquid crystal display apparatus having liquid crystal display element immersed in cooling medium

Rear projection display apparatus and translucent screen for use therein

For obtaining both high brightness under condition of small size and simplified structure, and for achieving suppression of increase in temperature of liquid crystal display elements and polarizing elements in a liquid crystal display apparatus, a liquid crystal display element converts light from a light source into a display picture depending on a driving signal, and an optical projection system contains a first optical element and projects a light signal toward an object of projection. A space is defined by an incident side polarizing element or the liquid crystal display element, the first optical element and a holding member, and the space is filled up with a cooling medium.

In a projection lens device having at least two plastic lenses for magnification-projecting an original image displayed on a display screen onto a screen, one of the two plastic lens is convex at a center thereof toward the screen and concave at a periphery thereof, and the other lens has a weak positive refractive power toward the screen at a center thereof and a stronger positive refractive power at a periphery thereof. A variation of a lens power due to a change of a surrounding environment is cancelled out by the concave shape at the periphery of the one lens and the positive refractive power at the periphery of the other lens.

Temperature compensating lens system for projection television

Disclosed is a projection lens system for use in an optical system for magnifying and projecting original images displayed on plural image display devices onto a screen through projection lenses provided in corresponding relation to the image display devices, which projection lens system comprises plural lens elements and in which according to colors or degrees of fineness of original images, the number of constituent lenses, or the shape of lens surface, or an effective aperture of at least one constituent lens element surface, or the number of constituent lenses and the shape of lens surface, or the number of constituent lenses and an effective aperture of at least one constituent lens element surface, or the shape of lens surface and an effective aperture of at least one constituent lens element surface, or the number of constituent lenses, the shape of lens surface and an effective aperture of at least one constituent lens element surface, are changed at a time.

Video projector with optical color balance

In a projection system wherein an optical system comprising a first lens for correcting a spherical aberration dependent on the aperture length, a second lens for enlargement and a third lens for correcting a field curvature, projects an image reproduced on a CRT having a curved phosphor surface, onto a screen, the third lens is spaced from the CRT so that the region of the phosphor surface which again totally reflects a light which has been totally reflected by a screen-side surface of the third lens is limited to the edge portion of an effective region of the phosphor surface.

Growing community of inventors

Yokohama, Japan

Shigeru Inaoka