Pioneer Electronic Corporation

Takayuki Yoshioka

Hideki Yamamoto

Shinichi Hasegawa

Takashi Terai

Naruhiko Atsuchi

Kazuyuki Shirai

Tadashi Yoshida

Yukio Ozaki

Kazuya Akiyama

Takashi Nagashima

Noriyasu Kato

Isao Tomisawa

Akira Nitta

Tomohiko Matsushita

Saori Wagatsuma

A stereoscopic display apparatus such that when an viewing point position of an observer is moved, a stereoscopic image similar to that observed at the moved position is obtained. A plurality of images according to a plurality of viewing point positions are generated from right/left image generating apparatuses. One of the plurality of images selected by a switching device is supplied to an image display apparatus. An observer observes a stereoscopic image by a liquid crystal driving apparatus, liquid crystal polarizing plates, and polarizing spectacles. Infrared rays from infrared light emitting devices are partially obstructed by the observer and are received by infrared photosensitive devices. A position detection processing circuit judges the image according to an viewing point position of the observer from detection signals, thereby switching the switching device to the right/left image generating apparatuses.

Stereoscopic display apparatus for generating images in accordance with an observer's viewing position

A projection type picture display apparatus, includes a light source; a polarizing beam splitter capable of reflecting or transmitting an incident light; a decomposing/synthesizing prism assembly capable of receiving a reflected light from the polarizing beam splitter to decompose the incident light into red, green and blue lights, also capable of receiving reflected red, green and blue lights to synthesize these lights so as to produce a synthesized light; a plurality of reflective type liquid crystal displays capable of receiving, modulating and reflecting red, green and blue lights; a projection optical system capable of receiving a picture light passing through the polarizing beam splitter to project an enlarged picture on a screen. In particular, the decomposing/synthesizing prism assembly has a first dichroic mirror reflecting a first color light but transmitting a second and third color lights, and has a second dichroic mirror reflecting the second color light but transmitting the first and third color lights, with the first and second dichroic mirror intersected with each other at a predetermined operable angle.

Projection type picture display apparatus

A rear projection television set is disclosed which includes a screen assembly, a reflector mirror located behind the screen assembly, and a projection source having a lens system for projecting rays of light to a rear side of the screen assembly through the reflector mirror. The projection source is arranged below the reflector mirror. A ray of light emitted along an optical axis of the lens system of the projection source is reflected by the reflector mirror. A positional relationship among the screen assembly, the projection source and the reflector mirror is determined so that the reflected ray of light is incidental from an upper side to a lower side relative to the screen.

Projection system for projection TV set

A liquid cooling type projector is provided with greater flexibility to meet different screen sizes of a projection television and, thus, contributes to the reduction of production cost. The projector has a cylindrical frame containing a projection lens unit mounted by a liquid-tight member thereto and coupled at a rear end to a CRT in liquid-tight arrangement such that a liquid-sealing space is established between the projection lens and the CRT. In particular, the projection lens unit is arranged so as to be movable with respect to the frame along its optical axis. Also, the liquid-tight member is arranged to maintain the liquid-tight condition regardless of the position of the projection lens unit relative to the frame. Thus, the projection lens unit can arbitrarily be displaced towards and away from the CRT, increasing a focusing range. Accordingly, the projector will successfully be matched to different sizes of projection screens contributing to the reduction of the production cost of projection televisions.

Projector in a projection television

A projection lens has a five-group structure, in which a first-group lens is a positive lens, a second-group lens is a negative lens, third- and fourth-group lenses are respectively positive lenses, and a fifth-group lens is a negative lens. The projection lens has a half view angle of 34.degree. or greater, and satisfies the following conditions: 0.04&lt;d.sub.4 /f.sub.0 &lt;0.08, 0.2&lt;.phi..sub.1 &lt;0.9, -0.6&lt;.phi..sub.2 &lt;0, 0.7&lt;.phi..sub.3 &lt;1.0, 0&lt;.phi..sub.4 &lt;0.5, and -1.36&lt;.phi..sub.5 &lt;-0.6, where: f.sub.0 : focal distance of the overall system, d.sub.4 : on-axis interval between the second-group lens and the third-group lens, .phi..sub.1 : power of the first-group lens, .phi..sub.2 : power of the second-group lens, .phi..sub.3 : power of the third-group lens, .phi..sub.4 : power of the fourth-group lens, and .phi..sub.5 : power of the fifth-group lens, (where .phi..sub.1 -.phi..sub.5 are respectively values obtained when the optical power of the overall system is set to 1).

Image projection lens

A coupled lens assembly comprises a plurality of lens units coupled by an intermediate layer disposed between the adjoining lens units, the intermediate layers being formed of an additional type silicone filler. A coupled lens assembly comprises a plurality of lens units coupled by an intermediate layer disposed between the adjoining lens units and formed of a bonding agent. Each of the lens units has a central lens portion and a peripheral portion surrounding the central lens portion and wherein one of the adjoining lens units has a flanged portion formed to a peripheral portion and the other one of the adjoining lens units has an engaging portion formed to the peripheral portion to be engaged with the flanged portion when both the lens units are coupled with optical axes of both the lens units being aligned. A groove is formed to at least one of the peripheral portions of the adjoining lens units for receiving an excessive fillet such as bonding agent when the filler is excessively applied and/or a discharge passage is formed to at least one of the peripheral portions of the adjoining lens units for discharging the excessive filler outward the coupled lens assembly. The groove may be formed so as to communicate with the discharge passage.

Coupled lens assembly

A three tube type projection television display device comprising red, green and blue projection tubes, wherein optical axes of projection lenses for the inclined projection tubes are off centered, instead of preparing a number of optical couplers of different sizes, from that of the inclined projection tubes by an eccentricity of .delta. when a projection picture size is varied for correcting a trapezoidal distortion in the same way as in the Scheimpflug rule, providing good registration on the screen and also bringing the projected pictures into focus on the entire screen.

Three tube color television projection display device

A projection lens consists of a first lens group including a positive lens, a second lens group including a meniscus type lens having a comparatively low refractive power, a third lens group including a bonded negative lens, a fourth lens group including a double convex lens, a fifth lens group including a lens having a comparatively low positive refractive power and a sixth lens group including a negative lens having a concave surface at the screen side, whereby, when a lens power of the whole lens system is 1 and a lens power of each lens group is designated by .psi..sub.X (1-6), respective lens powers will be given by the following a-e:

Projection lens

A projection lens system including seven lens elements for use in a projection television which comprises, in order from the screen side, a first lens unit composed of a positive lens element, a second lens unit composed of an aspherical lens element made of plastic in a meniscus form having at least one aspherical surface, a third lens unit composed of a concave lens element, a fourth lens unit composed of a positive cemented lens having a convex surface on both sides, a fifth lens unit composed of a positive lens element made of plastic in meniscus form having at least one aspherical surface, and a sixth lens unit composed of a negative lens element which has a concave surface directed toward the screen, the sixth lens unit being made of a plastic lens in meniscus form having at least one aspherical surface.

Projection lens systems for use in projection television

A temperature-compensated lens system of positive power includes a plastic lens having a convex surface, and a liquid lens of negative power made of a liquid or gel material and held against the convex surface of the plastic lens, the liquid lens having a temperature coefficient dn/dT ranging from -4.times.10.sup.-4 to -2.0.times.10.sup.-4 /.degree.C. indicating the temperature-dependent variation in the refractive index of the liquid lens. The lens system is highly resistant to temperature-dependent variations.

Temperature-compensated lens system

A projection lens system is disclosed which comprises, in order from a screen side, a first lens element having a positive focal length, a second lens element having a negative focal length, a third lens element having a positive focal length, a fourth lens element having a positive focal length and a fifth lens element having a negative focal length and a concave surface directed toward the screen side. The first and second lens element are made of plastic. Lens surfaces of the first and second lens elements are aspherical. Lens surfaces of the third and fourth lens elements are aspherical. The fifth lens element may be made of plastic. Lens surfaces of the fifth lens unit are aspherical. The system meets the following conditions:

Projection lens system

A projection lens system is disclosed which comprises in order from a screen side, a first lens unit having a positive focal length, a second lens unit having a negative focal length, a third lens unit having a positive focal length, a fourth lens unit having a positive focal length and a fifth lens unit having a negative focal length and a concave surface directed toward the screen side. The first and second lens units being made of plastic. At least one of lens surfaces of the first and second lens unit is aspherical. At least one of lens surfaces of the third and fourth lens units is aspherical. The fifth lens unit is made of plastic and at least one of lens surfaces of the fifth lens unit is aspherical.

Growing community of inventors

Tokyo, Japan

Takayuki Yoshioka