Sony Corporation

Eiji Yano

Motoyuki Ohtake

Ken Tanaka

Tatsuyuki Takahashi

Takuya Tsutsumi

Tsutomu Naitou

Seiji Sato

Seizi Sato

Hisashi Suwa

Katsuyuki Koizumi

Susumu Matsubara

A lens includes a front group including a plurality of lens groups; and a rear group that is provided on an image side of the front group and that includes a negative lens and a positive lens. The positive lens has a flat lens surface on its image side, and is tiltable about a spherical center of its object side lens surface that is convex on the object side. When a lens system is inclined, the positive lens is tilted in relation to the optical axis of the lens system based on: a focal length of the overall lens system; an angle of the optical axis of the lens system after being inclined in relation to the optical axis before being inclined; a distance between the image side lens surface of the positive lens and the image plane; and a refractive index of the positive lens.

Zoom lens and imaging apparatus

A zoom lens includes: a front group including a plurality of movable lens groups; and a rear group that is provided on an image side of the front group and that includes a negative lens and a positive lens. The positive lens has a flat lens surface on its image side, and is tiltable about a spherical center of its object side lens surface that is convex on the object side. When a lens system is inclined, the positive lens is tilted in relation to the optical axis of the lens system based on: a focal length of the overall lens system; an angle of the optical axis of the lens system after being inclined in relation to the optical axis before being inclined; a distance between the image side lens surface of the positive lens and the image plane; and a refractive index of the positive lens.

A zoom lens including a varifocal lens unit having a plurality of movable lens groups, and a prism disposed on an image side of the varifocal lens unit. The prism has an incident plane on which a light flux from the varifocal lens unit enters, and an exit plane from which the light flux is emitted toward an image plane, and is configured such that the incident plane or the exit plane or both planes can be inclined with respect to an optical axis, whereby a field of view is shifted by a predetermined amount by inclining the plane.

A zoom lens includes a varifocal lens unit including a plurality of movable lens groups, and a prism disposed on an image side of the varifocal lens unit. The prism has an incident plane into which a light flux from the varifocal lens unit enters, and an exit plane from which the light flux is emitted toward an image plane, the exit plane capable of being inclined with respect to an optical axis, the exit plane inclined in accordance with a following conditional expression '&#x3b1;=&#x2212;f&#xd7;&#x3b8;/[Bf(n&#x2212;1)]', where &#x3b1;: an angle formed by a normal of the exit plane and the optical axis, f: a focus distance of a whole lens system, &#x3b8;: a turning angle of a lens system, Bf: a distance from the exit plane of the prism to the image plane along the optical axis, and n: a refraction index of the prism.

An adaptor having the same size as that of a standardized tape cassette accommodates a small-sized tape cassette for insertion into a recording and/or reproducing apparatus and includes an upper adaptor half formed to become openable and/or closable, a pair of tape withdrawing levers for withdrawing a magnetic tape from the small-sized tape cassette, and a pair of coupling members for coupling the upper adaptor half to the tape withdrawing levers, wherein when the upper adaptor half is rotated in its closing direction, the tape withdrawing levers are rotated to withdraw the magnetic tape so that the magnetic tape is extended within the adaptor.

Adaptor for a small-sized tape cassette

A small-sized tape cassette adaptor system in which a small-sized tape cassette is accommodated in an adaptor whose size is the same as that of a standardized tape cassette so that the small-sized tape cassette may be loaded into a recording and/or reproducing apparatus utilizing the standardized tape cassette. Tape withdrawing levers are provided within the small-sized tape cassette for withdrawing a magnetic tape, and a rotating member is mounted within the adaptor in a position for rotating the tape withdrawing levers, so that the tape withdrawing levers are rotated by the rotating member upon insertion of the small-sized tape cassette into the adaptor.

The present invention is concerned with a helical scan type rotary magnetic head device employed for example in a video tape recorder in which the magnetic tape is caused to run obliquely while it contacts the head and in which recording tracks are formed on the magnetic tape at a predetermined angle of inclination relative to the tape. According to the present invention, the tape guide drum along the side of which the magnetic tape is caused to run while contacting with it has a cut-out at its portion free of contact with the magnetic tape, while a rotary transformer adapted for receiving and transmitting recording and/or reproducing signals at or from a rotary magnetic head is mounted so as to be enclosed within the interior of the tape guide drum to reduce the size and thickness of the rotary magnetic head device.

Rotary magnetic head and guide drum assembly with reduce mounting height

A magnetic recording and/or reproducing apparatus which includes a rotary magnetic head device, a reel block base plate provided on a chassis plate and having a pair of reel blocks horizontally reciprocable relative to the rotary magnetic head device and operatively engaged with a pair of tape reels of a tape cassette, a cassette holder which is supported by a supporting arm on the chassis base plate so as to be vertically movable relative to the reel block and in which the tape cassette is inserted and retained, an operating mode changeover lever for selecting the various operating modes, including constant speed running, rapid feed and rewind modes, for the magnetic tape pulled out of the tape cassette and loaded into the predetermined tape path, and a drive gear driven into rotation by a driving electric motor, wherein the drive gear is operatively associated with the supporting arm and the reel block base plate. The drive gear is driven into rotation to cause vertical movement of the cassette holder and the reciprocating movement of the reel block base plate. An operating lever adapted for being turned by the drive gear is operatively associated with the operating mode changeover lever, and turned to shift the operating mode changeover lever to select one of the predetermined operating modes. In this manner, the operations of loading the tape cassette and the magnetic tape and of selecting the operating mode may be performed by one and the same driving motor to reduce the number of the driving motors and the size and the thickness of the apparatus, while the cassette attachment and detachment and magnetic tape loading and unloading operations can be performed expeditiously.

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Tokyo, Japan

Eiji Yano