Alps Electric Co., Ltd.

Nissho Giken Kabushiki Kaisha

Eiki Matsuo

Tatsumaro Yamashita

Hitoshi Yoshiyuki

Masamichi Hayashi

Masataka Negishi

To provide a high-brightness, small, low-cost optical apparatus which covers a wide-angle to super-wide-angle region and which reliably corrects various aberrations with a small number of lenses. At least one negative lens unit, a meniscus lensthat is convex on an object side, an aperture stop S, and a double-convex positive lensare arranged in order from the object side. At least one of the lenses positioned on the object side of the aperture stop S and the positive lensinclude respective aspherical surfaces. When va is an average Abbe number of all of the lenses excluding the meniscus lens, vb is an Abbe number of the meniscus lens, f is a focal length of the entire system, fis a combined focal length of the negative lens unit and the meniscus lens, ts is a distance between the aperture stop and the positive lens along an axis, L is a distance between a vertex of a lens surface nearest to the object side and a vertex of a lens surface nearest to the image side, tis a central thickness of the meniscus lens, &#x3b8;s is an incident angle of a chief ray that passes through the aperture stop at a maximum angle of view, 1.4&#x3c;va/vb, 0&#x3c;ts/L&#x3c;0.1, 0.2&#x3c;t/L&#x3c;0.5, &#x2212;10&#x3c;f/f&#x3c;&#x2212;1.0, and 25&#xb0;&#x3c;&#x3b8;s&#x3c;40&#xb0; are satisfied.

Optical apparatus

An actuator includes a holder having a movement hole, a lens barrel which moves within the movement hole, and driving means for driving the lens barrel. Each of the driving means is provided with driving members composed of an artificial muscle. The lens barrel can be suitably moved within the movement hole by making the driving members perform a predetermined operation.

Actuator, optical apparatus using actuator, and method of manufacturing actuator

A front group is formed of a negative first lens as a meniscus lens which is convex at the object side and a negative second lens, and a rear group is formed of a biconvex positive third lens, an aperture stop, a negative fourth lens and a biconvex positive fifth lens. The first lens is a glass lens, and the second lens is a plastic aspherical lens. The following conditions are satisfied: &#x2212;2.4&#x3c;fI/f&#x3c;&#x2212;1.55, 0.15&#x3c;f2/f1&#x3c;0.35, va&#x3c;29, and vb&#x3e;50, where f denotes a focal distance of a whole system, f1 denotes a focal distance of the first lens, f2 denotes a focal distance of the second lens, fI denotes a focal distance of the front group, va denotes an average value of abbe numbers of the third and the forth lenses, and vb denotes an average value of abbe numbers of the rest of the lenses.

Optical device

When a voltage is applied between outside electrodes and a common electrode that constitute driving parts of a driving unit provided between a holder holding a lens and a lens barrel, as shown in FIG., respective dielectric elastomers provided in the driving parts are slightly deformed in a direction that is crushed in an X&#x2013;Xdirection. Thus, the entire lens can be slightly moved in the direction of an arrow (X-direction). This enables an optical axis O'&#x2014;O&#x2032; of the lens to coincide with or get closer to a reference optical axis.

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Nagano-ken, Japan

Eiki Matsuo