摘要:
In the disclosed holographic recording method, when multiplex recording of data of a plurality of pages is performed, exposure time of a hologram of a final page to be recorded is fixed irrespective of a degree of multiplicity while an exposure time of each page is changed and diffraction efficiencies of the holograms of the plurality of pages becomes equal.
摘要:
An optical recording/reproducing apparatus having excellent resistance against vibration and noise is provided. In recording, coherent light is polarization-modulated with a spatial light modulator to generate signal light and reference light whose polarization directions are crossed at right angles with each other. The signal light permeates a polarizing beam splitter, and is incident to a quarter wavelength plate. The reference light passes through a passing hole, is diffused by a light diffuser and is incident to the quarter wavelength plate. The reference and signal light are converted into circularly polarized light which revolve in directions opposite to each other and condensed by a condenser lens, and then a predetermined area of an optical recording medium is irradiated with the reference and signal light. Thus, the reference and signal light are generated by modulating the incident light from the same light source and are coaxially incident to the polarizing beam splitter.
摘要:
A holographic recording and/or retrieval method and apparatus are provided. An optical recording medium is used which has a recording layer, formed on a surface of a transparent substrate, through which light having an incident angle of a predetermined value or more with respect to the surface is guided, and which changes a refractive index or absorption coefficient upon simultaneous irradiation of signal light of a predetermined wavelength and reference light, and can record holograms by holding the changed refractive index or absorption coefficient. During recording, a hologram is recorded by simultaneously irradiating the recording layer with signal light of predetermined wavelength and reference light. During retrieval, reading light of wavelength that does not change a refractive index or absorption coefficient of the recording layer is guided through the recording layer, and a hologram is retrieved by diffracted light produced when the reading light is guided through the recording layer.
摘要:
Information recorded as a hologram in a predetermined position of an optical recording medium is reproduced, and subsequently the reproduced information is re-recorded and retained in the same position as the predetermined position as a hologram. Alternatively, information recorded as a hologram in a predetermined position of an optical recording medium is reproduced, and subsequently the reproduced information is re-recorded and retained in a position different from the predetermined position as a hologram easily.
摘要:
A hologram is recorded by irradiating, with a reference light beam, a region corresponding to an intensity distribution of a signal light beam on an optical recording medium. For example, the reference light beam having the intensity distribution which substantially coincides with the intensity distribution of the signal light beam is generated, and only the region which substantially coincides with the region irradiated by the signal light beam (i.e., the signal light beam defocused region) is irradiated with the reference light beam. This enables only the necessary region to be exposed and the regions which need not be exposed not to be exposed. Accordingly, the hologram can be recorded without losing information of the signal light beam and thus high-density recording can be realized.
摘要:
The present invention relates to a method for producing an optical recording medium. In the method, on the surface of a recording layer formed by spin-coating a first coating solution containing a photo-isomerizable component, a second coating solution that contains a photo-isomerizable component that can be isomerized by radiation having the same wavelength as radiation used for isomerizing the photo-isomerizable component contained in the recording layer and incapable of dissolving the recording layer is spin-coated to form an intermediate layer. Since the intermediate layer thus formed cannot be dissolved by the first coating solution, a recording layer is further laminated on this layer. Thus, it becomes possible to make the recording layer thicker and also to provide a high-density recording characteristic.
摘要:
The present invention discloses a hologram erasing method, in which a predetermined hologram is erased by irradiating a predetermined region of a hologram recording medium in which the hologram to be erased is recorded with a reference light beam and a signal light beam holding a random data pattern at the same time. In this method, the signal light beam and the reference light beam interfere with each other in the medium, and a Fourier transform hologram recorded in the region where the interference occurs is destroyed and erased by interference light beam. That is, a data page for erasing including a random pattern is overwritten to erase an original data page. According to the present invention, the hologram recorded in the optical recording medium can be selectively and completely erased in a simple method.
摘要:
The present invention relates to a method for producing an optical recording medium. In the method, on the surface of a recording layer formed by spin-coating a first coating solution containing a photo-isomerizable component, a second coating solution that contains a photo-isomerizable component that can be isomerized by radiation having the same wavelength as radiation used for isomerizing the photo-isomerizable component contained in the recording layer and incapable of dissolving the recording layer is spin-coated to form an intermediate layer. Since the intermediate layer thus formed cannot be dissolved by the first coating solution, a recording layer is further laminated on this layer. Thus, it becomes possible to make the recording layer thicker and also to provide a high-density recording characteristic.
摘要:
Laser light output from a laser light source is irradiated onto a transmission-type scale. Due to movement of the transmission-type scale, a polarization angle of transmitted light varies in accordance with variations in orientations of half-wave plates arrayed in a longitudinal direction. It is difficult for the polarization angle to be affected by noise factors such as external light or the like. Light intensity of a polarized light component, which is transmitted through an analyzer and detected at a photo-detector, varies in accordance with the polarization angle. Thus, the light intensity varies as the transmission-type scale moves, and a detection signal is output to a movement amount computing device. When an amount of movement is computed on the basis of the signal, the exact amount of movement can be detected.
摘要:
The present invention discloses a hologram erasing method, in which a predetermined hologram is erased by irradiating a predetermined region of a hologram recording medium in which the hologram to be erased is recorded with a reference light beam and a signal light beam holding a random data pattern at the same time. In this method, the signal light beam and the reference light beam interfere with each other in the medium, and a Fourier transform hologram recorded in the region where the interference occurs is destroyed and erased by interference light beam. That is, a data page for erasing including a random pattern is overwritten to erase an original data page. According to the present invention, the hologram recorded in the optical recording medium can be selectively and completely erased in a simple method.