Home | Links | Contact Us | More About Intellectual Property | Bookmark
Search patents:
Home Optical Systems Compound-objective-lens-having-two-focal-points

 Lens array and method of making same
FIG. 4 is a flowchart illustrating a method 400 in accordance with an embodiment of the present ...


 Optical signal processor, method of its control, method of its designing, and method of its production
The present invention has been accomplished in the light of the conventional technologies discussed ...


 Method and system for equalizing PMD using incremental delay switching
OF THE PREFERRED EMBODIMENTS The present invention is a PMD compensator based upon delay elements ...


 Polarization scrambler and integrated optical circuit making use thereof
What is claimed is: 1. A polarization scrambler comprising: a first splitter for splitting an ...


 Fiber optic circulator
FIGS. 3 and 4 illustrate the difference in imaging which is fundamental to the operation of the ...


 Method and apparatus for providing transformation of the polarization of light
In one aspect, the invention provides an optical apparatus for transforming the polarization of ...


 Polarization mode dispersion compensation
An object of the invention is to provide a method of PMD compensation using a polarisation ...


 Method for compensating polarization mode dispersion in a waveguide and a polarization mode dispersion compensator
The object of the present invention is thus to specify a method for PMD compensation and a PMD ...


 Film confined to a frame having relative anisotropic expansion characteristics
The following terms should be understood in the description of the present invention according to ...


 Method for formatting partially overlapping holograms
In one embodiment of the present invention, a method of writing holograms includes: numbering ...


 Compound objective lens having two focal points

Details
Inventors: Komma, Yoshiaki; Mizuno, Sadao; Nishino, Seiji;
Assignee: Matsushita Electric Industrial Co., Ltd. (Osaka, JP)
Primary Examiner: Henry; Jon W.
Assistant Examiner:
Attorney, Agent or Firm: Lowe Hauptman Gopstein Gilman & Berner

A compound objective lens is composed of a hologram lens or transmitting a part of incident light without any diffraction to form a beam of transmitted light and diffracting a remaining part of the incident light to form a beam of first-order diffracted light, and an objective lens for converging the transmitted light to form a first converging spot on a front surface of a thin type of first information medium and converging the diffracted light to form a second converging spot on a front surface of a thick type of second information medium. Because the hologram selectively functions as a concave lens for the diffracted light, a curvature of the transmitted light differs from that of the diffracted light. Therefore, even though the first and second information mediums have different thicknesses, the transmitted light incident on rear surface of the first information medium is converged on the its front surface, and the diffracted light incident on a rear surface of the second information medium is converged on the its front surface. That is, the compound objective lens has two focal points.

DETAILED DESCRIPTION A first object of the present invention is to provide, with due consideration to the drawbacks of such a conventional objective lens having a focal point, a compound objective lens having two focal points.
A second object of the present invention is to provide an imaging optical system having the compound objective lens in which light transmitting through the compound objective lens is converged at a diffraction limit on two converging spots placed at different depths of an information medium.
A third object of the present invention is to provide an optical head apparatus having the imaging optical system in which information is recorded, reproduced or erased on or from one of the converging spots of the information medium at which light is converged by the action of the imaging optical system.
A fourth object of the present invention is to provide a high density optical disk in which a series of first recording pits is formed to record pieces of information at high density on a thin substrate.
A fifth object of the present invention is to provide an optical disk apparatus in which information is recorded or reproduced on or from the optical disk with the compound objective lens regardless of whether a series of recording pits expressing pieces of information is recorded or reproduced on or from the high density optical disk having a thin thickness or a conventional compact disk having an ordinary thickness.
A sixth object of the present invention is to provide a binary focus microscope having two focal points in which two types of images drawn at different depths are simultaneously observed.
A seventh object of the present invention is to provide an alignment apparatus in which two types of images drawn at different depths are aligned with the binary focus microscope.
An eighth object of the present invention is to provide a focusing method for focusing light on an information medium with the optical head apparatus.
A ninth embodiment of the present invention is to provide an information reproducing method for reproducing a piece of recording information recorded on a high density optical disk having a thin thickness


Related patents
  Optical pickup device for reproducing discs of two types with different densities by double beam focuses of different sizes
Therefore, it is an object of the present invention to provide an optical pickup device capable of reproducing discs of two kinds having different densities by forming ...
  Multiple focus lens, an optical head apparatus and an optical information recording-reproducing apparatus
In order to solve these and other problems, this invention aims to provide a multiple focus lens designed to substantially standardize the conditions for correction of ...
  Polarizing plate and liquid-crystal display containing the same
What is claimed is: 1. A polarizing plate comprising: a protective film, 5 to 150 μm thick, composed of cyclic-olefin-based resin having an anchor coat agent ...
  Polarization independent wavelength tunable filter based on birefringence compensation
It is an object of the present invention to provide a tunable, polarization independent wavelength filter utilizing birefringence compensation. It is a further object of ...
  Wavelength division multiplexer and demultiplexer
This invention is based on the observation that many filters have the characteristic property that the filter passes incident light of wavelengths within a ...
  Tunable filtering device for optical communications
To solve the above problems, it is an objective of the present invention to provide a tunable filtering device for optical communications, which has a simple ...
  Wavelength selection switches for optical application
This invention is based on the observation that, by making use of filters that selectively passes and reflects radiation of different wavelengths, it is possible to ...
  All-optical holographic code division multiple access switch
These shortcomings and other limitations and deficiencies are obviated in accordance with the present invention by free-space optical switch, and concomitant method, ...
  Three-dimensional image display device having an elementary hologram panel and method for manufacturing the elementary hologram panel
The present invention relates to a three-dimensional image display device for displaying a three-dimensional object and particularly to a three-dimensional display ...
  Method and apparatus for displaying three-dimensional images
What is claimed is: 1. A method for producing a three-dimensional image, comprising the steps of: simultaneously modulating a--preferably spatially coherent--light beam ...

0.004

Archive: All patents - Links

Copyright (c)2006 Eipa-patents.org - All rights reserved