Asahi Glass Company, Limited

Hiroaki Shimozono

Koichi Murata

Shoichi Takeuchi

Norihito Nakazawa

Nobuyasu Ikutame

Yuji Aizawa

An imaging lens is provided, whose lens characteristics can be switched between e.g. normal imaging and close-up imaging without requiring mechanically movable mechanism or attachment/removal of another lens. Switching of lens function is realized by combining a liquid crystal diffraction lens and a refractive lens and applying a voltage to a liquid crystal layer of the liquid crystal lens. The liquid crystal lens is constituted by two liquid crystal lenses that are laminated together so that their polarization directions producing lens functions are perpendicular to each other, which suppresses chromatic aberration and achieves good imaging characteristics by appropriately selecting focal lengths and Abbe numbers.

Imaging lens

An objective lens in which a first wavelength is used in reading a first optical disk, a second wavelength is used in recording or reading a second optical disk, and a phase shifter provided with annular step portions having a center coincident with an optical axis is formed in a single surface of the objective lens, the phase shifter producing a phase difference with respect to light having the first wavelength and light having the second wavelength, is presented. The objective lens can read well both a CD and a DVD.

Objective lens having two aspheric surfaces and a phase shifter and optical device including the same

An objective lens used in the recording of a CD or a DVD, wherein a ringed step portion is provided in a first surface of an objective lens, the step portion is provided in a first surface of an objective lens, and the step portion producing a phase difference with respect to light having a first wavelength. In addition, a ringed step portion is provided in a second surface of the objective lens. The second step portion produces a phase difference with respect to light having a second wavelength.

Objective lens and optical device

An optical device for recording or reading two optical disks,in which the thickness of a transparent substrate of a first optical disk,is different from the thickness of a transparent substrate of a second optical disk,wherein the optical device has an objective lens,for collecting light from a first light source,and light from a second light source,onto data recording surfaces,by means of respective transparent substrates,of the optical disks,; an optical material,for forwarding the light from the first light surface,and the light from the second light source,and light from a second light source,before the lights reaches the objective lens,, and an auxiliary lens,provided between the second light surface,and the optical material

Optical device

An optical device wherein when reading of CD is conducted, light from a first optical light source 1 is passed through a first auxiliary lens 2, an optical material 3 and an objective lens 4 to be converged onto a data recording surface 5a of CD and when reading of DVD is conducted, light from a second light source 6 is passed through a second auxiliary lens 7, the optical material 3 and the objective lens 4 to be converged onto a data recording surface 8a of DVD.

Optical device for recording or reading data to an optical disk

An optical pick-up for reading data in the data recording surface of an optical data recording material by collecting light from a light source by means of an objective lens, and shining reflection light from the data recording surface onto a light receiving element through the objective lens, the optical pick-up being adapted to read data in the data recording surface of first and second optical data recording materials wherein the thickness of a protective substrate is different from each other, wherein the objective lens is so determined that the aberration is corrected in response to the thickness of the protective substrate of the first optical data recording material, and in reading data in the data recording surface of the second optical data recording material which has a thickness different from that of the first optical data recording material, the object.image distance is adjustable so as to adjust the aberration.

Optical pick-up, optical data recording apparatus and objective lens for

A hed-up display comprises a light source and a liquid crystal display device for displaying an image, and a hologram arranged on a windshield glass of a vehicle to diffract the light to an observer, wherein the hologram has the half width of the diffraction spectrum so that a white light entering into the vehicle from the outside is diffracted as substantially a white light.

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Yokohama, Japan

Hiroaki Shimozono