Abstract: A two-focal-point pickup device capable of suppressing the generation of glitch or bump in reproduced signal. The optical pickup device irradiates a light beam emitted from a light source onto an optical recording medium to form a light spot on a track of a recording surface of the optical recording medium to read the optical recording medium while controlling the position of the light spot relative to the track of the recording surface. The optical pickup device includes a converging lens section coaxially disposed in an optical axis of the light beam to converge the light beam onto the recording surface; and a hologram lens section coaxially disposed in the optical axis of the light beam to diffract the light beam.

Abstract: A two-focal-point pickup device capable of suppressing the generation of glitch or bump in reproduced signal. The optical pickup device irradiates a light beam emitted from a light source onto an optical recording medium to form a light spot on a track of a recording surface of the optical recording medium to read the optical recording medium while controlling the position of the light spot relative to the track of the recording surface. The optical pickup device includes a converging lens section coaxially disposed in an optical axis of the light beam to converge the light beam onto the recording surface; and a hologram lens section coaxially disposed in the optical axis of the light beam to diffract the light beam.

Abstract: A substrate having an optical element on an input surface thereof receives a light beam not having a desired beam shape and shapes the light beam into a predetermined intensity distribution. The substrate may further include a second optical element for providing a predetermined phase pattern to the light beam provided by the first optical element. The first optical element may, for example, circularize an elliptical light beam using a soft aperture for differential power attenuation or by altering the divergence of the light beam along the different axes of the light beam. When the divergence angles are altered and the collimating optical element is provided on the output surface, the thickness of the transparent substrate is determined in accordance with a resultant difference in the divergence and/or with the initial difference in beam size along each axis and with a required circularity.

Abstract: The holographic storage and retrieval system according to the present invention comprises one convex reflector and one concave reflector having the same optical axis. The reflective surfaces of the two reflectors are opposite each other. The concave reflector is normally larger than the convex reflector. The holographic storage medium is positioned at the focal surface of the concave reflector. The spherical reflector system according to the present invention has nearly ideal performance off-axis: high bandwidth, low aberration imaging is permitted at a number of radial and axial locations. Thus, multiple SLM/CCD pairs can be placed off-axis to access the same storage medium and implement multiple interconnects.

Abstract: A method of producing an optical element including a photopolymer layer between two holograms is disclosed. The holograms have the same diffraction spacing and refractive index, but the first hologram has an efficiency of about one-half that of the second hologram, preferably about fifty per cent and ninety-five per cent respectively. The photopolymer is polymerized to adjust the refractive index of the photopolymer until output beams will overlap and cancel each other.

Abstract: A two-focal-point pickup device capable of suppressing the generation of glitch or bump in reproduced signal. The optical pickup device irradiates a light beam emitted from a light source onto an optical recording medium to form a light spot on a track of a recording surface of the optical recording medium to read the optical recording medium while controlling the position of the light spot relative to the track of the recording surface. The optical pickup device includes a converging lens section coaxially disposed in an optical axis of the light beam to converge the light beam onto the recording surface; and a hologram lens section coaxially disposed in the optical axis of the light beam to diffract the light beam.

Abstract: An optical pickup apparatus compatible with at least two types of optical recording media, using light beams having respective different wavelengths for recording and reading information, the optical pickup apparatus including two laser light sources to emit light beams having the different wavelengths, respectively, a holographic lens, including a holographic ring, to transmittal of the light beams emitted from the laser light sources in an inner region of the holographic ring, and diffracting a specific light beam among the light beams emitted from the laser light sources in an outer region relative to the inner region, an objective lens to focus the light beams passed through the holographic ring lens on the respective information recording surfaces of the two types of the optical recording media, optical elements to alter optical paths of the light beams reflected from the information recording surfaces of the optical recording media; and two photodetectors to individually detect optical information from

Abstract: A wavelength sensitive hologram which combines the 780 nm laser beam and the 650 nm laser beam to produce a compact DVD optical pickup. The 780 nm laser beam is incident on the hologram at an angle so that the first order diffraction from the hologram propagates along the optical axis of the hologram. The wavefront recorded on the hologram also contains aberration correction components so that the focused 780 nm laser beam on the CD substrate is nearly perfect or at least diffraction limited. The 650 nm laser beam is incident normal to the hologram plane so that the 0 order diffraction of the 650 nm laser beam remains propagating along the optical axis of the hologram.

Abstract: A high-resolution light-beam scanning apparatus utilizing only mass-producible holograms instead of utilizing auxiliary optical systems such as an optical lens or a mirror having curvature, and capable of compensating for disadvantages including scanning beam thickening and variation, failure of a rotatable hologram to rotate at a constant velocity, displacement of a scanning beam position in the scanning direction and the cross scanning direction due to a mode hop of a wavelength of a semiconductor laser, and deviation of a base of a rotatable hologram from a parallel state, which disadvantages are detrimental to efforts for increasing the resolution of a hologram scanner and lowering the cost thereof, the light-beam scanning apparatus being characterized in that provided in the rotatable hologram (1) and the fixed plate (2) arediffraction gratings for minimizing:either a sum total of values obtained by weighting:a square of an optical path length difference between a) an optical path of a light flux measure

Abstract: A method of manufacturing a fixed hologram plate of a light-beam scanning apparatus for diffracting a light incident from a light source portion by a rotatable hologram, scanning by the diffracted light through the rotation of the rotatable hologram, diffracting the resulting light by the fixed hologram plate, and for conducting a light-beam scanning on a scanning surface. The method includes the steps of preparing an interference fringe distribution of the fixed hologram plate by two waves: a first wave having a spherical aberration, a transverse aberration of the first wave is in the Y direction, the transverse wave including an astigmatism and a coma; and a second wave having a spherical aberration and astigmatism, and having a wavelength different from a wavelength of a reconstructing wave that is selected to minimize distortion, wherein a transverse aberration of the second wave is in the X direction.

Abstract: Coma of an objective lens occurs depending on the lens-forming condition when plural disks of different substrate thickness are recorded and reproduced. An objective lens according to this invention is not influenced by the coma even if the thickness of the substrates is changed. For this purpose, a diffraction grating whose aberration is corrected is formed on the first side of an aspheric objective lens. Due to this correction, light beams having different diffraction orders, e.g. 0th order diffracted light and +1st order diffracted light, are focused respectively on two kinds of substrates of different thickness. The whole objective lens is tilted to correct its axial coma, and the tilt angle is predetermined to be substantially identical with respect to plural substrates which are different in thickness.

Abstract: Bow can be minimized by an auxiliary grating in a post deflection path of the diffracted beam from the hologon which is disposed in non-parallel relationship to the plane of rotation of the hologon. The ellipticity of the spot which generates the scan line and intensity variation in the scan beam can be minimized by using a dispersive element, preferably a prism, between the hologon and the bow compensation grating with its dispersion in a direction opposite to the direction of the dispersion of the hologon and of the auxiliary grating. Another grating before the hologon can be used to correct for wavelength shift induced cross-scan error associated with the dispersion in the hologon and a bow compensation grating following the hologon.

Abstract: This invention comprises a novel apparatus for recording a holographic groove pattern on a diffraction grating blank. The recording apparatus is configured using newly developed groups of analytical equations. The invention further comprises the novel holographic diffraction grating made with the inventive recording apparatus. The invention additionally comprises monochromators and spectrometers equipped with the inventive holographic diffraction grating. Further, the invention comprises a monochromator configured to reduce aberrations using a newly developed group of analytical equations. Additionally, the invention comprises a method to reduce aberrations in monochromators and spectrometers using newly developed groups of analytical equations.

Abstract: This patent teaches a low cost imager. The imager has an refractive objective lens 10 having a surface with a color correcting diffractive pattern 16 and an infrared transmitting polymeric field lens 18 having a substantially flat surface with a first field-correcting diffractive pattern. In this imager, the first field-correcting diffractive pattern operates to reduce aberrations of an image. In some embodiments, the imager further has a second field-correcting diffractive pattern on the field lens, where the first and second field-correcting diffractive pattern cooperating to reduce aberrations of the image. Additionally, this patent teaches a refractive/diffractive achromatic lens group 30. This achromat 30 can be used in the disclosed imager or in other optical devices. The achromatic group 30 has a refractive lens 10 and a lens 28 having a substantially flat surface with a surface diffractive pattern 16, the surface diffractive pattern cooperating with the refractive lens to reduce chromatic aberrations.

Abstract: A holographic optical device having a light transmissive substrate with a first holographic optical element carried by the substrate, and a second holographic optical element also carried by the substrate but laterally offset from the first holographic optical element. The first holographic optical element diffracts waves from each data point in a display source into a collimated plane wave such that the plane wave is trapped inside the substrate by internal reflection, and the first holographic optical element also corrects field aberrations over the entire field of view by being recorded using at least one aspheric wavefront. The second holographic optical element diffracts the trapped plane waves out of the substrate.

Abstract: Reflective image-providing displays viewed with holographically diffused light are provided. As one particular and preferred embodiment, a liquid crystal display component is presented comprising a liquid crystal display element backed with a reflective transmission holographic diffuser. Images of good contrast may be displayed and viewed from the liquid crystal display component under ambient lighting conditions and without further requirement of supplemental light sources, such as edge-lighting and backlighting.

Abstract: A technique for correcting wavefront aberrations introduced by large primary optical elements in portions of the electromagnetic spectrum. The aberrations of the primary element are first transferred to a beacon beam and this aberrated beam is interfered with a reference beam in a holographic medium. These beams are then turned off and a beam from a distant object, containing the same aberrations, is allowed to diffract from the hologram. The diffracted beam from the hologram contains the image of the distant object with aberrations removed. Use of this technique permits the construction of large optical elements inexpensively, since surface tolerances of the elements can be substantially relaxed.

Abstract: This device comprises an optical source emitting a single-wavelength light beam. An index grating has been recorded in a holographic device by the interference of two plane light beams, both being beams at a single wavelength with one and the same determined value and being concurrent in the holographic device. The holographic device is illuminated by the light beam and delivers a single-wavelength beam whose radiation pattern has a limited angular passband. The wavelength of the reading beam may be different from that of the recording beams. Its orientation is then different from that of the beams.

Abstract: An achromatic optical system that preferably includes a light source for emitting light therefrom, an achromatic optical element positioned to receive light emitted from the light source, and an optical detector positioned to receive and detect light passing through the optical element. The achromatic optical element preferably includes a substrate having opposing sides, a first computer generated hologram positioned on one side of the substrate and adapted to receive light emitted from the light source, and a second computer generated hologram positionally aligned on the opposite side of the substrate and adapted to receive light passing through the substrate from the first hologram at a predetermined location thereon.

Abstract: A low weight, achromatic, athermal, long wave infrared objective lens with one element having a positive optical power and the other element having a negative optical power but with a higher thermo-optic coefficient than the thermo-optic coefficient of the first element. A diffractive color correcting optical surface is generated on one surface of one of the elements and aspheric surfaces may be included for further performance gains.

Abstract: A hologram display apparatus in which chromatic aberration hardly occurs even when light of a wide bandwidth is used as a reproducing light. The apparatus has a hologram combiner 10 with a diffraction characteristic of lens, and is adapted to receive a signal light including information to be displayed and to generate, in response to the signal light, a reproduced light to be seen and acknowledged by an observer. The hologram combiner 10 has a curved surface with a constant curvature in at least one of a first direction and a second direction perpendicular to the first direction. The center 01 of curvature of the curved surface is positioned at substantially the same position of the center 02 of curvature of the lens equivalent to the hologram 11.

Abstract: Reflective image-providing displays viewed with holographically diffused light are provided. As one particular and preferred embodiment, a liquid crystal display component is presented comprising a liquid crystal display element backed with a reflective transmission holographic diffuser. Images of good contrast may be displayed and viewed from the liquid crystal display component under ambient lighting conditions and without further requirement of supplemental light sources, such as edge-lighting and backlighting.

Abstract: A head-up display for an automobile utilizing a light transmission hologram optical device as well as a light reflection hologram optical device. The head-up display is installed in a large truck or in a special freight car, such as a container car or a ready mixed concrete car, so that the head-up display informs a driver of information of conditions of dead ground of the car. The head-up display includes a hologram optical projection system and a holographic combiner. The projection system for projecting the light has a light source, an LCD for partially transmitting and shielding the light of the light source, and a light transmission hologram optical device for projecting the light. The holographic combiner for displaying the image includes a light reflection hologram optical device.

Abstract: An optical system is disclosed which focuses a polychromatic source to an extended focal pencil. The implementation makes use of two holographic optical elements (HOEs) fabricated and aligned to form a deliberate longitudinal color dispersion, but to alleviate lateral chromatic effects. Consequently, the HOE doublet focuses different wavelengths of the source to different locations along the optical axis. The strong intensity of the focused wavelengths dominate at each location, so that the overall beam has a near-diffraction-limited 1/e.sup.2 spot size and suffers only relatively weak background illumination. An alternative optical system using bulk lenses and several possible applications for the device are also described.

Abstract: An adaptive optics imaging system uses a double pumped phase conjugate mirror (DPCM) to compensate for phase, amplitude or polarization aberrations imposed upon a multi-pixel object beam. A remote reference beam is used to sample an aberrating medium through which the object beam is transmitted, and forms a shared hologram in a two-beam coupling medium with a local reference beam having known phase characteristics, generally plane-wave. An output beam is produced in the phase conjugate direction of the local reference beam, with the pixelized difference in phase characteristics between the output and local reference beams corresponding to the pixelized difference in phase characteristics between the object and remote reference beams; the remote reference beam is also preferably planar.

Abstract: An object beam is passed through an aberrating medium to produce a diffraction distorted image therein, which is imaged upon a spatial light modulator. A probe beam measures the phase aberrated wavefront within the aberrating medium and is used to produce an interference pattern which is employed to produce phase encoding signals to be fed back to the spatial light modulator for compensating in part for the phase distortion of the phase aberrated wavefront. The result is an output image having a substantially reduced degree of distortion.

Abstract: The infra-red diffractive optical lens will remedy chromatism faults and offer excellent compactness; in addition, it does not call for a cooling device. It comprises a first convergent lens made of a material corresponding to the operational infra-red band width considered and a second convergent lens formed by a surface hologram. This hologram is obtained by accurate machining of one of the diopters of the first convergent lens according to machining data optimized by digital calculations. The first lens is preferably made of zinc sulfide. This system can operate simultaneously in the 8 to 12 microns infra-red band and the 1.06 microns laser channel.

Abstract: A head mounted display having an image source, an optical relay system and a combiner for producing an image from the image source to the eye of a pilot in which the optical system includes at least one diffractive surface to compensate for aberrations and distortions in the display.

Abstract: A method and apparatus using a holographic storage medium for direct transmission of an optical image which can compensate for distortions occurring during transmission of the image.

Abstract: A holographic grating element is provided which enables tracing different scan lines. The element is divided into a plurality of sectors. A first grating pattern is provided which diffracts a beam in one direction, and a second grating pattern is next to the first and diffracts the scan beam in the reverse direction. Sectors can be produced with different sector sizes to enable scanning at different rates in the reverse direction, or in successive scans in the same direction. Angle relationships are described to produce diffraction patterns for a desired relationship between disc rotation and the angle of the scan line.

Abstract: A holographic sight which includes a base having at least one connector for mounting the base on a small arm, and a hologram of a reticle pattern, a compact laser light source for illuminating the hologram, and a power source for the laser diode, each mounted on the base. The sight also includes an achromatizer supported in the path of the light beam for reducing shifts in the position of the reticle pattern due to variations in the wavelength of the light beam emitted from the laser diode. The sight may further include means for circularizing the generally elliptical beam emitted by the laser diode to provide a uniform illumination pattern for the hologram. A brightness adjuster and position adjuster, for varying the brightness and relative position of the reticle, respectively, may also be provided.

Abstract: A non-regular reflection type holographic mirror which can reduce, when mounted as a reflection plate on a windshield of a vehicle, the inclination of a display image visually discerned by reflection and a process of manufacturing the same. The holographic mirror comprises a hologram plate including a transparent support member and a photosensitive agent layer formed on the transparent support member and having interference fringes formed therein such that the hologram plate has a function of a concave mirror at a first portion of the hologram plate and another function of a convex mirror at a second portion of the hologram plate on opposite sides of a horizontal center line. A reflection type display apparatus for a vehicle employing a non-regular reflection type hologram or a regular reflection type hologram constituting a concave mirror as a hologram combiner wherein a virtual image of a display unit is reversed into an erect image and compensated for in contraction to improve the discernibility.

Abstract: The holographic element of the present invention includes a holographic grating pattern that is impressed in the media of the element utilizing beams of electromagnetic energy of wavelength .lambda..sub.o. The holographic grating pattern is capable of manipulating a beam of electromagnetic energy having a wavelength .lambda..sub.c at which the media is not necessarily suitable for recording. The method for manufacturing the holographic element utilizes an object beam and a reference beam having aspherical wavefronts of wavelength .lambda..sub.o to create the grating pattern in the media. In the preferred embodiment, the aspherical object beam and reference beam are created utilizing parent holographic devices recorded with spherical beams. An alternative embodiment of the present invention is a doublet holographic device which incorporates two holographic elements that are formed in accordance with the present invention to manipulate a beam of electromagnetic energy of wavelength .lambda..sub.

Abstract: An optimized design method of a holographic optical element by calculating a correction coefficient so that an evaluating amount of a reconstructed light reconstructed by the holographic optical element can be minimized, the correction coefficient determining an aspheric term included in a phase transfer function, the phase transfer function representing a shape of an interference fringe recorded on the holographic optical element. According to the method, the wavefront aberration is expressed via a linear function of the correction coefficient by positioning a main axis point on a characteristic evaluating surface onto which the reconstructed light is projected, so that a wavefront aberration of the reconstructed light can be minimized. Then, the correction coefficient is calculated based on the linear function so that the evaluating amount can minimized.

Abstract: A laser diode distance measurement device includes a laser diode 10 which emits light 20 to a lens 22 which provides focussed light 24 incident on a target 26. The light 24 is reflected from the target 26 back to the laser diode 10 which causes the laser diode 10 to emit a light 28 which exhibits intensity pulses (due to coherent interference) related to the distance L to the target 26. A photodetector 30 provides a feedback signal indicative of the intensity of the light 28 to a distance measurement circuit 18. The laser diode 10 is driven by an up-ramp signal that reduces electronic processing and at a frequency that reduces speckle noise. The distance measurement circuit 18 blanks-out a portion of the feedback signal during discontinuities of the laser diode drive signal to minimize associated noise from distorting the distance measurement.

Abstract: A holographic laser beam scanning apparatus capable of removing astigmatism created by a hologram disc of the apparatus due to discordance of wave fronts of the laser beams, thereby allowing precise scanning to be effected. The apparatus includes a focusing lens for focusing a laser beam generated by a laser generator, and a hologram for converting the focused beam into a parallel beam, both the lens and hologram being disposed between the laser generator for generating the laser beam and the hologram disc for irradiating the parallel beam as a diffracted beam.

Abstract: A low-cost head-up display suitable for automobiles consists of a transmitting diffractive element (3) located below an observer's line of sight for diffracting light from an information display (2)onto a combiner glass or the windscreen (1) of the automobile, and an opaque mask (4) positioned close to the diffractive (3) element so that specular reflections from the display (2) are screened from the observer's field of view.

Abstract: A hologram scanner includes a reproducing light source for generating a collimated reproducing light beam, a hologram disk being adapted to rotate, and a hologram disposed on the hologram disk for deflecting the reproducing light beam by diffraction so as to scan an image surface by the deflected reproducing light beam during a rotation of the hologram disk. The hologram has interference fringes recorded by a mutual interference of an object light of divergent spherical wave and a reference light of divergent spherical wave. The object light is generated by an object light source positioned at a first position apart from a hologram recording plane of the hologram disk, on which the hologram is to be recorded, by a first distance. The reference light is generated by a reference light source positioned at a second position apart from the hologram recording plane by a second distance.

Abstract: Optical structures are disclosed that comprise selected combinations of refractive and diffractive type optical elements wherein net chromatic aberrational effects are minimized in images formed by said structures. With the disclosed structures, chromatic aberrational contributions from each type of optical element, having characteristically opposite algebraic sense, are essentially cancelled out by means of proper distribution of optical power plus suitable arrangement and relative location of the said optical elements. Advantages over the prior art are demonstrated in four general types of optical structures.

Abstract: A head-up display for a vehicle, including a primary image reflection hologram supported by a transparent substrate located in the vehicle operator's field of view for the ambient scene in front of the vehicle, a light source for providing playback illumination to the primary image hologram, and a guard hologram in front of the primary image hologram for substantially reflecting ambient illumination that otherwise could spuriously turn on the first reflection hologram, the guard hologram having an angular bandwidth and a spectral bandwidth that are greater than the angular bandwidth and the spectral bandwidth of the primary image hologram, and having an optical density of 2.0 or greater. The guard hologram can be parallel fringe reflection hologram or a slant fringe reflection hologram.