Nippondenso Co., Ltd.

Tukasa Koumura

Michio Hisanaga

Tadashi Hattori

Kiyoshi Saeki

Hideaki Nishikawa

A varifocal lens whose variable focal length can be controlled by, for example, an electric signal, and suitable for use in bar code readers, etc. A varifocal lens comprises a first pressure chamber defined between a glass substrate and a transparent elastic film. The transparent elastic film is faced to the surface of the planar glass substrate having parallel surfaces with a spacer incorporated therebetween to provide the first pressure chamber. A pump is provided adjacent to the first pressure chamber via a communicating path for charging an operating liquid to the first pressure chamber from a second pressure chamber of the pump by electrically deforming the transparent elastic film to form a lens having a variable focal length. The transparent elastic film has a film thickness distribution as such to provide a spherical plane in the central portion thereof and a third order curved surface in the periphery thereof. In this manner, a lens free of aberration can be obtained when a liquid is fed into the first pressure chamber to form a spherical plane.

Varifocal lens

An optical data reader including a device for producing a light beam, and a device for changing a condensing position of the light beams before the light beam is reflected from a target such as a bar code. The device for changing the condensing position is either a variable focus lens or mirror, each adapted to change the curvature of the surface of the lens or mirror in order to move the condensing position cyclically and continuously. The variable focus mirror changes the shape of its reflecting surface in response to electrical signals from a driving circuit. Excess pressure within the mirror caused by the mirror surface being attracted inwards is expelled through intake/outlet ports formed in the drive electrode. The variable focus lens alters the focal length of the lens each time the curvature of the surface thereof is changed. Preferably, the curvature of the lens surface is changed by increasing fluid pressure within the lens, while the curvature of the variable focus mirror is electrically driven. Either the variable focus lens or mirror is disposed in the optical path between the light source and the target. The light source is usually a laser or laser diode.

Optical data reader capable of quickly changing a condensing position of

In order to perform micromachining of a precision smooth curved surface on a workpiece, light emitted from a mercury lamp is transmitted through a photomask, Fourier transform lens, aperture material, and inverse Fourier transform lens, after which it is beamed upon the workpiece material to be surface-machined and a positive photoresist layer which is formed on the surface of the workpiece material. By means of the foregoing structure, the high-frequency optical components which are included in the light emitted from the mercury lamp and which may cause roughening of curved-surface machining are made to converge at a location away from the optical axis and are removed by means of an aperture provided thereupon, with the only the residual low-frequency optical components being transmitted through the aperture, and so the intensity profile of the light which is beamed upon the positive photoresist layer is smoothed and a smooth-surface curved surface is transcribed to the positive photoresist layer.

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Toyota, Japan

Tukasa Koumura