Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Yoshito Miyatake

Keiki Yoshitsugu

Shinya Sannohe

Kazuhiko Ishimaru

Katsu Yamada

Hiroshi Takahara

Yoshimasa Fushimi

Takaaki Tanaka

Yoshitomi Nagaoka

Yasuo Nakajima

Mamoru Takeda

Yoshiharu Yamamoto

Hideki Ohmae

Yuichi Kimura

Sadayoshi Hotta

Tsutomu Muraji

Yoshihiro Masumoto

Shin-Ichiro Ishihara

Sinya Sannohe

Akira Otsuka

Naoto Yumiki

Shigekazu Yamagishi

Takakazu Bito

Ichiro Yamashita

Hiroshi Kubota

Shusuke Ono

Hiroshi Miyai

Mitsuhiro Wada

Yoneharu Takubo

Takeo Santo

Hideki Omae

Hitoshi Noda

Mamoru Honjo

Syusuke Ono

Sinya San-Nohe

Yasuhiko Wagamitsu

Yasuhiro Horio

There are provided a camera system and an interchangeable lens that are compatible with a contrast detection method. A camera system () has an interchangeable lens unit () and a camera body (). A lens microcomputer () changes the movable range of a second lens group (L) via a focus lens drive controller () depending on whether a second holder () is driven by the focus lens drive controller () and a focus motor () on the basis of angle information inputted to a zoom ring () of the interchangeable lens unit (), or the second holder () is driven by the focus lens drive controller () on the basis of contrast information.

Camera system and interchangeable lens

A zoom lens system comprising a plurality of lens units each composed of at least one lens element, wherein the zoom lens system, in order from the object side to the image side, comprises: a first lens unit having positive optical power and comprising four lens elements; a second lens unit having negative optical power; and a third lens unit having positive optical power; wherein in zooming from a wide-angle limit to a telephoto limit at the time of image taking, at least the first lens unit is moved along an optical axis direction so as to achieve variable magnification, and wherein the conditions are satisfied: 0.30&#x3c;f/f&#x3c;0.70 and Z=f/f&#x3e;20.5 (fis a composite focal length of the first lens unit, fis a focal length of the entire system at a wide-angle limit, and fis a focal length of the entire system at a telephoto limit), an imaging device and a camera are provided.

Zoom lens system, imaging device and camera

A zoom lens system comprising a first lens unit having negative power, a second lens unit having positive power and a third lens unit having positive power, wherein: the first lens unit comprises a first lens element having a concave surface at least on the image side and negative power and a second lens element having a convex surface at least on the object side and positive power; the second lens unit comprises a first cemented lens element of two lens elements having power of mutually different signs and a second cemented lens element of two lens elements having power of mutually different signs; in zooming, all of the lens units move along an optical axis; and conditions (1): 5.0&#x3c;&#x3b1;i&#x3c;20.0 and (I-2): n&#x2267;1.9 (where, 3.2&#x3c;f/fand &#x3c9;&#x3e;35, &#x3b1;iis an incident angle of a principal ray to an image sensor at a maximum image height at a wide-angle limit, nis a refractive index of the first lens element to the d-line, &#x3c9;is a half view angle at a wide-angle limit, and fand fare focal lengths of the entire system at a telephoto limit and a wide-angle limit, respectively) are satisfied.

A zoom lens system comprising a first lens unit having negative power, a second lens unit having positive power and a third lens unit having positive power, wherein: the first lens unit comprises a first lens element having a concave surface at least on the image side and negative power and a second lens element having a convex surface at least on the object side and positive power; the second lens unit comprises a cemented lens element fabricated by two lens elements having optical power of mutually different signs and one single lens element; in zooming, all of the lens units move along an optical axis; and conditions (1): 5.0&#x3c;&#x3b1;i&#x3c;20.0 and (I-2): n&#x2267;1.9 (where, 3.2&#x3c;f/fand &#x3c9;&#x3e;35, &#x3b1;iis an incident angle of a principal ray to an image sensor at a maximum image height at a wide-angle limit, nis a refractive index of the first lens element to the d-line, &#x3c9;is a half view angle at a wide-angle limit, and fand fare focal lengths of the entire system at a telephoto limit and a wide-angle limit, respectively) are satisfied.

A zoom lens system comprising a first lens unit having negative power, a second lens unit having positive power and a third lens unit having positive power, wherein: the first lens unit comprises a first lens element having a concave surface at least on the image side and negative power and a second lens element having a convex surface at least on the object side and positive power; the second lens unit comprises a single third lens element, a cemented lens element of two lens elements having power of mutually different signs and a single sixth lens element; in zooming, all of the lens units move along an optical axis; and conditions (1): 5.0&#x3c;&#x3b1;i&#x3c;20.0 and (I-2): n&#x2267;1.9 (where, 3.2&#x3c;f/fand &#x3c9;&#x3e;35, &#x3b1;iis an incident angle of a principal ray to an image sensor at a maximum image height at a wide-angle limit, nis a refractive index of the first lens element to the d-line, &#x3c9;is a half view angle at a wide-angle limit, and fand fare focal lengths of the entire system at a telephoto limit and a wide-angle limit, respectively) are satisfied.

A zoom lens system comprising a first lens unit having negative power, a second lens unit having positive power and a third lens unit having positive power, wherein: the first lens unit comprises a first lens element having a concave surface at least on the image side and negative power and a second lens element having a convex surface at least on the object side and positive power; the second lens unit comprises a cemented lens element fabricated by two lens elements having optical power of mutually different signs and one single lens element; in zooming, all of the lens units move along an optical axis; and conditions (1): 5.0&#x3c;&#x3b1;i&#x3c;20.0 and (I-2): n&#x2267;1.9 (where, 3.2&#x3c;f/fand &#x3c9;&#x3e;35, &#x3b1;iis an incident angle of a principal ray to an image sensor at a maximum image height at a wide-angle limit, nis a refractive index of the first lens element to the d-line, &#x3c9;W is a half view angle at a wide-angle limit, and fand fare focal lengths of the entire system at a telephoto limit and a wide-angle limit, respectively) are satisfied.

It is an object to provide a zoom lens made of three groups having a zoom ratio of &#xd7;2.5 to &#xd7;3.2 if the object distance is &#x221e;, an field angle at the wide-angle end of 60&#xb0; to 70&#xb0;, high resolution, and a short optical total length when not in use. The zoom lens is made of a first lens group (G) with a negative power, a second lens group (G) with a positive power, and a third lens group (G) with a positive power, arranged in that order from an object side to an image plane (S) side. The first lens group (G) is made of a first lens (L) that is a negative meniscus lens whose surface with strong curvature is facing the image plane (S) side and a second lens (L) that is a positive meniscus lens whose surface with strong curvature is facing the object side, arranged in that order from the object side. The second lens group (G) is made of a third lens (L) that is a positive lens whose convex surface is facing the object side, a fourth lens (L) that is a positive lens, a fifth lens (L) that is a negative lens, and a sixth lens (L) that is a plano-convex lens whose convex surface is facing the image plane (S) side, arranged in that order from the object side. The third lens group (G) is made of a single seventh lens (L) that is a positive lens.

Zoom lens and electronic still camera using the same

A zoom lens comprising, disposed in order from an object side to an image surface side, a negative-power first lens group, a diaphragm, a positive-power second lens group, and a positive power third lens group, characterized in that, when zooming from a wide-angle end to a telelscope end, an air gap between the first lens group and the second lens group shrinks and an air gap between the second lens group and the third lens group expands, the third lens group is movable in an optical axis direction for focusing, and a zoom ratio at a shooting distance of &#x221e; is 2.5- to 3.2-magnification.

Zoom lens and electronic still camera using it

Where a stack projection operation is carried out using first and second projection display units, it is arranged such that the first projection display unit projects a crosshatch pattern continuously in time while on the other hand, the second projection display unit projects a pattern identical with that crosshatch pattern such that the pattern flashes at given intervals of time. Thereafter, the state of superposition between the patterns projected from the two projection display units is examined to carry out inter-set convergence adjustment between the display units.

Convergence adjusting method, signal generating apparatus, and projection display unit

In the optical apparatus, the projection lens has a first lens group and a second lens group, the color synthesizing optical system has a transparent plate, dichroic mirrors and a plane mirror, the second lens group is disposed between the color synthesizing optical system and the polarization beam splitters, and the plane including the normal line of the plane of the transparent plate, the color synthesizing planes of the dichroic mirrors and the optical axis of the projection lens is perpendicular to the plane including the normal line of the polarizing and splitting planes of the polarization beam splitters and the optical axis of the projection lens.

Optical apparatus, projection display apparatus and optical compensation

In an optical system phase device such as .lambda./2 plate or a .lambda./4 plate is used to convert S polarization to P polarization and vice versa. In the projection display, a white light emitted from a light source is separated by a color separation optical system, including dichroic mirrors or a dichroic prism, into three primary colors which are modulated by optical modulation elements. Then, the modulated lights are synthesized by a color synthesis optical system and projected by a projection element onto a screen. When appropriate plates are inserted appropriately in the optical system of the projection display, the conversion between S and P polarization occurs and an optical bandwidth becomes narrow, and color purity can be improved. A thick transparent plate is preferably adhered to the optical modulation element. A light absorption film is applied to an ineffective plane of the transparent plate. The phase device is preferably inserted between an optical modulation element and a transparent plate or the like to improve contrast. The invention can be applied to liquid crystal panels such as liquid crystal/resin display panels, light beam writing type display panel or micro mirror display panel. Preferably, the phase device is set to be rotatable so as to adjust contrast appropriately.

Liquid crystal panel and projection display with use of liquid crystal

A projection lens includes sequentially from a screen side a first lens group which has a negative power, a second lens group which has a weaker power than that of the first lens group, a third lens group which has a positive power, a fourth lens group which has a positive power, and at least one transparent prism, wherein the fourth lens group is placed on the third lens group side of the transparent prism so as to be close to or in contact with the transparent prism. In the projection lens, a back focus of the main lens group is much longer compared with a focal length. A projection display apparatus using this projection lens is composed of one main lens group, three auxiliary lenses, and three polarizer-beam splitters, and a color combining optical system for combining three primary color components of red, green, and blue into one light beam is placed between the main lens group and the auxiliary lens.

Projection lens and projection display apparatus

A light valve includes a light valve layer for forming an optical image as variations in its ability to scatter light, and two substrates between which the light valve layer is sandwiched and at least one of which is transparent. The light valve satisfies the following condition: ##EQU1## where t denotes a central thickness of the at least one of the substrates, n denotes a refractive index of the at least one of the substrates and d denotes a maximum diameter of an effective display area of the light valve layer. Alternatively, a transparent plate can be optically coupled to one of the substrates by a transparent body. In this case, the same condition is satisfied except that the thickness refers to a central thickness from a face of the transparent plate remote from the transparent body to the light valve layer.

Growing community of inventors

Neyagawa, Japan

Yoshito Miyatake