Abstract: An image following information detecting device capable of obtaining information for causing a central portion of an image to follow a line-of-sight of a user. The device includes: an image display system including an image light projecting unit , and a transmissive reflection member that reflects a part of the image light toward an eyeball and transmits other parts; and a line-of-sight detection system including at least one invisible light source, a diffractive optical element provided integrally with the transmissive reflection member and including a reflective diffraction portion that reflects and diffracts invisible light toward the eyeball,and a light receiving element that receives the invisible light reflected by the eyeball . A portion irradiated with a central portion of the image light of the transmissive reflection member and the reflective diffraction portion overlap each other when viewed from a thickness direction of the transmissive reflection member.

Abstract: In some embodiments, a head mounted display is provided, comprising a light guide, at least first and second diffraction gratings, alignment marks A1 and B1 associated with the first diffraction grating, and alignment marks A2 and B2 associated with the second diffraction grating. The first diffraction grating may be disposed on a first surface of the light guide, the first surface facing away from a light input. The second diffraction grating may be disposed on a second surface of the light guide, the second surface facing towards the light input. The second diffraction grating may be adapted to diffract at least some of the light input into the light guide, and the first diffraction grating may be adapted to diffract at least some light transmitted through the light guide back into the light guide.

Abstract: In some embodiments, a head mounted display is provided, comprising a light guide, at least first and second diffraction gratings, alignment marks A1 and B1 associated with the first diffraction grating, and alignment marks A2 and B2 associated with the second diffraction grating. The first diffraction grating may be disposed on a first surface of the light guide, the first surface facing away from a light input. The second diffraction grating may be disposed on a second surface of the light guide, the second surface facing towards the light input. The second diffraction grating may be adapted to diffract at least some of the light input into the light guide, and the first diffraction grating may be adapted to diffract at least some light transmitted through the light guide back into the light guide.

Abstract: A light irradiation device includes: a focus servo control unit including a light source, a spatial light modulating unit, and a light irradiating unit, for focus servo control so that the ideal focal position of light via an objective lens is such that distance between an ideal focal position and a hologram recording medium surface is smaller than distance from the surface to the lower layer side face of the recording layer, and the focal position of light via the objective lens is constant at the ideal focal position; an objective-lens/relay-lens distance adjusting unit to adjust distance between the objective lens and a relay lens close to the objective lens; a light reception unit to receive marker light; and a constant distance control unit to control the objective-lens/relay-lens distance adjusting unit based on error between the ideal position of the marker light, and the actual position of the marker light.

Abstract: A hologram reproducing apparatus includes a first reference light path leading laser light from a laser light source so that a hologram recording medium is irradiated with first reference light; a diffracted light path leading diffracted light, generated from the hologram recording medium by irradiation with the first reference light, to a light receiving element having a plurality of pixels; and a second reference light path leading second reference light, having the same polarization direction as that of the diffracted light, from the laser light source to the light receiving element. The second reference light path is provided with a phase modulating element so that the phase difference between the diffracted light and the second reference light in a light receiving surface of the light receiving element is adjusted within a predetermined range.

Abstract: A hologram device includes: a light source for applying light to a hologram recording medium having a recording layer in which information recording is performed by interference fringes between signal light and reference light; a spatial modulation unit that generates the signal light and/or the reference light and generates a marker light in a predetermined position within an incident surface of the light from the light source by performing spatial light modulation on the light from the light source; a light applying unit that applies the light subjected to spatial light modulation by the spatial light modulation unit to the hologram recording medium via an objective lens; a light receiving unit that receives the light applied via the objective lens through the hologram recording medium; and a tilt detection unit that obtains a tilt error signal representing an error from an ideal angle of a tilt angle as an incident angle of the applied light via the objective lens to an information recording surface of the

Abstract: A hologram recording/reproducing apparatus records data as a hologram by applying signal and reference light beams to a hologram-recording medium, obtains a diffracted light beam by applying a reproduction light beam to the hologram, and reproduces the data using the diffracted light beam. The hologram recording/reproducing apparatus includes an external-cavity light source, a polarization-control element that changes a polarization angle of a light beam emitted from the external-cavity light source, a polarizing-beam-splitting element that splits the light beam to obtain two light beams and that changes a ratio between amounts of the two light beams, a photoreceptor that receives one of the two light beams, a spatial light modulator that receives the other beam and that generates signal, reference, and reproduction light beams, and a control unit that changes the polarization angle or polarization state of the light beam.

Abstract: In a reproducing apparatus adapted to reproduce data recorded on a holographic recording medium, a reference light generator generates reference light for illuminating the holographic recording medium, and a coherent light generator generates coherent light having an intensity greater than the absolute value of a minimum amplitude of a reproduced image and having a phase equal to the phase of the reproduced image. An image signal acquisition unit senses the reproduced image produced by illuminating the holographic recording medium with the reference light and the coherent light, and acquires an image signal based on the reproduced image. A square root calculation unit calculates the square root of each of values constituting the image signal. A removal unit removes the component of the coherent light from the calculated square root, whereby the data recorded on the holographic recording medium is correctly reproduced.

Abstract: A recording and reproducing apparatus for recording data to and reproducing data from a hologram recording medium is provided. The recording and reproducing apparatus includes a light emitting unit for emitting light to be directed to the recording medium set at a predetermined position, a spatial light modulation unit for performing spatial light modulation on incident light by pixels, an image sensor for receiving incident light by pixels and converting the incident light into an electrical signal, an optical system for guiding the light emitted by the light emitting unit to the recording medium via the spatial light modulation unit while guiding, to the image sensor, light reflected from the recording medium in response to the light emitted by the light emitting unit, and a determination unit for controlling the spatial light modulation unit.

Abstract: A hologram device includes: a light source for applying light to a hologram recording medium having a recording layer in which information recording is performed by interference fringes between signal light and reference light; a spatial modulation unit that generates the signal light and/or the reference light and generates a marker light in a predetermined position within an incident surface of the light from the light source by performing spatial light modulation on the light from the light source; a light applying unit that applies the light subjected to spatial light modulation by the spatial light modulation unit to the hologram recording medium via an objective lens; a light receiving unit that receives the light applied via the objective lens through the hologram recording medium; and a tilt detection unit that obtains a tilt error signal representing an error from an ideal angle of a tilt angle as an incident angle of the applied light via the objective lens to an information recording surface of the

Abstract: A light irradiation device includes: a focus servo control unit including a light source, a spatial light modulating unit, and a light irradiating unit, for focus servo control so that the ideal focal position of light via an objective lens is such that distance between an ideal focal position and a hologram recording medium surface is smaller than distance from the surface to the lower layer side face of the recording layer, and the focal position of light via the objective lens is constant at the ideal focal position; an objective-lens/relay-lens distance adjusting unit to adjust distance between the objective lens and a relay lens close to the objective lens; a light reception unit to receive marker light; and a constant distance control unit to control the objective-lens/relay-lens distance adjusting unit based on error between the ideal position of the marker light, and the actual position of the marker light.

Abstract: A hologram reproducing apparatus includes a reference-light spatial-light modulating section that displays a reference light pattern for generating reference light, an image sensor that has pixels arrayed two-dimensionally that receive diffractive light generated by irradiating the reference light on a hologram recording medium, and a control unit that processes an electric signal from the image sensor and reproduces recording data. The control unit detects a predetermined area electric signal, detects a hologram electric signal, subtracts the predetermined area electric signal from the hologram electric signal to obtain a reproduced signal after noise reduction, and reproduces the recording data from the reproduced signal after noise reduction.

Abstract: A reproduction device includes a light-emitting unit that emits reference light and coherent light, which is generated so as to have uniform light intensity and uniform phase, onto a hologram recording medium on which data is recorded by an interference pattern of signal light and the reference light, and a light-attenuating unit that attenuates the light intensity of the coherent light.

Abstract: In a reproduction apparatus, a modulation control generates reference light by performing a drive control on respective pixels in reference light areas of a spatial light modulator and a phase modulator and also generates DC light added to a reproduction image by performing a drive control in a signal light area of a spatial light modulator to apply a spatial light intensity modulation at a same modulation amount in all pixels and performing a drive control in a signal light area of the phase modulator while setting one part of phase modulation amounts as a phase modulation amount for setting a same phase as a reference phase in the reproduction image obtained from a hologram recording medium in accordance with irradiation of the reference light and setting the other part of the phase modulation amounts as a phase modulation amount different by ? with respect to the one part of the phase modulation amounts.

Abstract: A recording and reproducing device performs recording and reproduction on a hologram recording medium on which data is recorded by the use of interference fringes formed by signal light and reference light. The device includes: a light generation device including a spatial light modulator which performs spatial light modulation on incident light, and generating the signal and reference lights in the recording and the reference light in the reproduction; an image sensor for receiving the incident light and obtaining a light reception signal; an optical system for guiding the signal and reference lights to the hologram recording medium and reproduction light to the image sensor; and a band limiting device inserted on a Fourier plane in an optical path of the optical system, and having a transmittance set to be lower in a central area thereof than in a peripheral area thereof, to perform band limitation on the incident light.

Abstract: A hologram recording/reproducing apparatus records data as a hologram by applying signal and reference light beams to a hologram-recording medium, obtains a diffracted light beam by applying a reproduction light beam to the hologram, and reproduces the data using the diffracted light beam. The hologram recording/reproducing apparatus includes an external-cavity light source, a polarization-control element that changes a polarization angle of a light beam emitted from the external-cavity light source, a polarizing-beam-splitting element that splits the light beam to obtain two light beams and that changes a ratio between amounts of the two light beams, a photoreceptor that receives one of the two light beams, a spatial light modulator that receives the other beam and that generates signal, reference, and reproduction light beams, and a control unit that changes the polarization angle or polarization state of the light beam.

Abstract: A hologram reproducing apparatus includes a reference-light spatial-light modulating section that displays a reference light pattern for generating reference light, an image sensor that has pixels arrayed two-dimensionally that receive diffractive light generated by irradiating the reference light on a hologram recording medium, and a control unit that processes an electric signal from the image sensor and reproduces recording data. The control unit detects a predetermined area electric signal, detects a hologram electric signal, subtracts the predetermined area electric signal from the hologram electric signal to obtain a reproduced signal after noise reduction, and reproduces the recording data from the reproduced signal after noise reduction.

Abstract: A hologram reproducing apparatus includes a first reference light path leading laser light from a laser light source so that a hologram recording medium is irradiated with first reference light; a diffracted light path leading diffracted light, generated from the hologram recording medium by irradiation with the first reference light, to a light receiving element having a plurality of pixels; and a second reference light path leading second reference light, having the same polarization direction as that of the diffracted light, from the laser light source to the light receiving element. The second reference light path is provided with a phase modulating element so that the phase difference between the diffracted light and the second reference light in a light receiving surface of the light receiving element is adjusted within a predetermined range.

Abstract: In a reproducing apparatus adapted to reproduce data recorded on a holographic recording medium, a reference light generator generates reference light for illuminating the holographic recording medium, and a coherent light generator generates coherent light having an intensity greater than the absolute value of a minimum amplitude of a reproduced image and having a phase equal to the phase of the reproduced image. An image signal acquisition unit senses the reproduced image produced by illuminating the holographic recording medium with the reference light and the coherent light, and acquires an image signal based on the reproduced image. A square root calculation unit calculates the square root of each of values constituting the image signal. A removal unit removes the component of the coherent light from the calculated square root, whereby the data recorded on the holographic recording medium is correctly reproduced.

Abstract: A recording and reproducing apparatus for recording data to and reproducing data from a hologram recording medium is provided. The recording and reproducing apparatus includes a light emitting unit for emitting light to be directed to the recording medium set at a predetermined position, a spatial light modulation unit for performing spatial light modulation on incident light by pixels, an image sensor for receiving incident light by pixels and converting the incident light into an electrical signal, an optical system for guiding the light emitted by the light emitting unit to the recording medium via the spatial light modulation unit while guiding, to the image sensor, light reflected from the recording medium in response to the light emitted by the light emitting unit, and a determination unit for controlling the spatial light modulation unit.