Abstract: A miniature display system uses a reflective micro-display that reflects light perpendicular to the surface of the display to generate an image. Light from an off-axis light source is polarized and reflected by a prism to provide on-axis illumination light for the display. The prism uses total internal reflection and/or a polarizer as a beam splitting surface so as to increase the brightness of the image generated by the display. The optical system provides a virtual image with a large field of view so that the small display system can be used in portable, hand-held or head mounted systems to display a large amount of information to the user.

Abstract: A viewing optical system and an image-forming optical system, in which an intermediate image is formed once and two decentered prisms, i.e. first and second prisms, are arranged to correct each other's decentration aberrations, thereby attaining a wide viewing field angle and a short focal length. The second prism is placed closer to the image side than the first prism and has four optical surfaces, of which a first surface is an entrance surface, second and third surfaces are reflecting surfaces, and a fourth surface is an exit surface. In the second prism, an optical path crosses itself. At least one of the second and third surfaces has a rotationally asymmetric surface configuration that gives a power to a light beam and corrects aberrations due to decentration. The first prism has a reflecting surface, an entrance surface, and an exit surface. The reflecting surface has a rotationally asymmetric surface configuration that gives a power to a light beam and corrects aberrations due to decentration.

Abstract: The present invention is an optical apparatus, e.g. an image display apparatus, which enables observation of a clear image at a wide field angle with substantially no reduction in the brightness of the observation image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The optical apparatus has an image display device (6), and an ocular optical system (7) for leading an image of the image display device (6) to an observer's eyeball (1). The ocular optical system (7) includes, in order from the image side, a third surface (5) which forms an entrance surface, a first surface (3) which forms both a reflecting surface and an exit surface, and a second surface (4) which forms a reflecting surface. The first to third surfaces (3 to 5) are integrally formed with a medium put therebetween which has a refractive index larger than 1.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism placed on the object side and a second prism placed on the image side and does not form an intermediate image. The first and second prisms each have a first surface through which a light beam enters the prism, a second surface reflecting the incident light beam in the prism, a third surface reflecting the reflected light beam in the prism, and a fourth surface through which the light beam exits from the prism. At least one of the second and third surfaces has a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration. Any optical element that gives a refracting power contributing to the image-forming action of a light beam is not placed between the second prism and an image formed by the image-forming optical system.

Abstract: An optical system which is compact, lightweight and satisfactorily corrected for aberrations and may be suitably used as an imaging optical system or an ocular optical system for a head- or face-mounted image display apparatus which forms no intermediate image. The optical system includes an optical member (7) and a diffraction optical element (8), which are decentered with respect to each other. The optical member (7) has at least three adjacent optical surfaces, at least one of which is a curved surface. At least two reflections take place between the optical surfaces. The space between the optical surfaces is filled with a medium having a refractive index larger than 1. Light rays emitted from an image display device (6) enter the optical member (7) through a first transmitting surface (5) disposed to face the image display device (6) and are reflected by a first reflecting surface (3).

Abstract: A high-performance image-forming optical system made compact and thin with a minimal number of constituent optical elements and particularly suitable for use in a camera. A first prism is placed on the object side of a second prism. The first prism has a first transmitting surface, a first reflecting surface, a second reflecting surface, a third reflecting surface, and a second transmitting surface. The first transmitting surface and the third reflecting surface are the identical surface, and the first reflecting surface and the second transmitting surface are the identical surface. The second prism has an entrance surface, at least one reflecting surface, and an exit surface. The first prism and the second prism each have at least one reflecting surface with a rotationally asymmetric surface configuration that corrects decentration aberrations.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism placed on the object side and a second prism placed on the image side and does not form an intermediate image. The first prism has a first surface through which a light beam enters the first prism, a second surface reflecting the incident light beam in the prism, a third surface reflecting the reflected light beam in the prism, and a fourth surface through which the light beam exits from the prism. At least one of the second and third surfaces has a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration. The second prism has at least one reflecting surface that reflects a light beam in the prism.

Abstract: An apparatus and a method for loading and unloading a flying lens relative to the surface of an optical storage media is provided. The apparatus is comprises a flying lens, a movable optical module for supporting and positioning the lens, and a ramp that slidably engages the movable optical module to load and unload the flying lens. The flying lens is loaded, or moved into a position close to the surface of the moving optical storage media, when the speed is sufficient that aerodynamic forces prevent contact between the flying lens and the storage media. The flying lens is unloaded before the storage media slows or stops and is held in a parked position by the ramp. During the loading and unloading the alignment integrity of the optical path is maintained.

Abstract: An optical pickup includes: a light source, an object lens, and an aberration correction unit for correcting aberration by giving a phase difference to a light beam. The aberration correction unit corrects astigmatism caused by an optical system of the optical pickup.

Abstract: There is provided an image projector including (a) a light source, (b) a reflection mirror for reflecting flux of light emitted from the light source, (c) an image display unit for forming images, and (d) a relay system for transferring the flux of light to the image display unit, the relay system including a relay lens having a first convex surface through which the flux of light enters therein and a second convex surface through which the flux of light exits therefrom, a ratio of a radius of curvature of the first convex surface to a radius of a curvature of the second convex surface being determined in such a manner that aberration out of an optical axis of the relay lens is increased to thereby cause a converging point of the flux of light to displace from a calculated focal distance. For instance, the ratio is determined in the range of about 1:2 to about 1:3.

Abstract: A high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. The image-forming optical system has a first prism placed on the object side and a second prism placed on the image side and does not form an intermediate image. The first prism has a first surface through which a light beam from an object enters the first prism, and a second surface that reflects the light beam entering through the first surface in the first prism. The first surface also reflects the light beam reflected by the second surface in the first prism. The first prism further has a third surface through which the light beam reflected by the first surface exits from the first prism. The first or second surface has a rotationally asymmetric surface configuration that gives a power to a light beam. The second prism has at least one reflecting surface that reflects a light beam in the second prism.

Abstract: A head mounted display to view a created image and an external scene includes a display displaying the image and a prism receiving the image which includes a first surface for diffracting the image, and a second and third surface reflecting the image to a user of the head mounted display.

Abstract: An image-forming optical system, e.g. a variable-magnification optical system, using a compact decentered optical system capable of providing a clear image of minimal distortion even at a wide field angle. The image-forming optical system includes a first lens unit G1 disposed on the object side and formed from a decentered optical system, and a second lens unit G2 disposed on the image side of the first lens unit G1 and having at least one lens. The decentered optical system has at least one rotationally asymmetric surface having no axis of rotational symmetry in nor out of the surface to correct rotationally asymmetric aberrations caused by decentration. In the case of a variable-magnification optical system, a magnification change is effected by changing at least one spacing between the lens units.

Abstract: A reflective collimator for a laser, such as for use in a cutting or welding machine tool. The collimator requires no more than three mirrors, and can be configured with only two. The relative positions of a convex/concave mirror pair are adjusted to adjust the divergence of the output collimated beam. Adjustment is accomplished by translating two of the mirrors in linear paths along respective beam paths established in the collimator. A linkage interconnects the two translatable mirrors and includes a coupling which incorporates the triangular geometry of the beam path established by the mirrors, so that the translatable mirrors are linked to maintain alignment throughout the range of collimator adjustment. When one of the translatable mirrors is adjusted the linkage causes the second to track the first while maintaining precise alignment in the collimator.

Abstract: A multi-color optical display system is designed with a bi-fold prism assembly in a relay lens that, together with a multi-spectrally reflecting optical combiner, longitudinally corrects a multi-colored image composed of two or more discrete wavelengths of light. The prism assembly for a preferred two-color image typically includes three light reflecting surfaces, the first of which may be flat or curved and coated with a spectrally reflective coating of a given wavelength; the second of which is flat or curved, coated with a spectrally reflective coating of a given second wavelength, and spaced a small amount from the first surface; and the third of which is flat, separated from the first two by a large distance and angle, and uncoated. The coatings are chosen to each reflect a specific wavelength range of colored light used in the display system and to transmit all other wavelengths.

Abstract: A decentered prism optical system suitable for use as an ocular optical system used in combination with an objective optical system and favorably corrected for pupil aberration. A prism optical system (7) which receives an image formed by an objective lens includes a decentered prism (7) having at least three surfaces (3 to 5) decentered with respect to each other, wherein the space between the at least three surfaces (3 to 5) is filled with a transparent medium having a refractive index not smaller than 1.3. The optical path is reflected at least twice in the optical system (7), and the optical paths of light rays do not intersect each other. At least one reflecting surface (4) has a rotationally asymmetric surface configuration having no axis of rotational symmetry in nor out of the surface. The optical system has both the function of optically transmitting a pupil (1) by image formation and the function of optically transmitting an image and is satisfactorily corrected for pupil aberration.

Abstract: An image-forming optical system, e.g. a variable-magnification optical system, using a compact decentered optical system capable of providing a clear image of minimal distortion even at a wide field angle. The image-forming optical system includes a first lens unit G1 disposed on the object side and formed from a decentered optical system, and a second lens unit G2 disposed on the image side of the first lens unit G1 and having at least one lens. The decentered optical system has at least one rotationally asymmetric surface having no axis of rotational symmetry in nor out of the surface to correct rotationally asymmetric aberrations caused by decentration. In the case of a variable-magnification optical system, a magnification change is effected by changing at least one spacing between the lens units.

Abstract: An optical system capable of correcting aberrations due to three-dimensional decentration by using a rotationally asymmetric surface having no plane of symmetry. The optical system includes, from the ray bundle entrance side, a first surface (3) serving as both a first transmitting surface and a second reflecting surface, a second surface (4) as a first reflecting surface, and a third surface (5) as a second transmitting surface. The space between these surfaces is filled with a medium having a refractive index larger than 1. The first surface (3) is a three-dimensional surface having no plane of symmetry.

Abstract: A special concentric lens system having an air gap and at least one aspheric surface is provided to achieve a substantially uniform imaging performance in a wide angle of view with reduced aberrations.

Abstract: An optical system includes a two-stage aberration corrector having a static corrector lying on the optical path and a dynamic corrector lying on the optical path. The static corrector is fixed and is selected to correct the fixed aberration component of an optical beam. The dynamic corrector is controllably variable to correct the variable, angle-dependent aberration component of the beam. The dynamic corrector includes an astigmatism generator, a power generator, and a coma generator. The optical system also includes a window through which the optical path passes prior to reaching the aberration corrector, and a sensor in the optical path after the beam passes through the aberration corrector.

Abstract: Two lenses separated by an air gap provide spherical aberration compensation and focusing of a light beam to a focal point inside a data storage medium. The thickness of the air gap determines the amount of spherical aberration compensation provided. The distance between the lens pair and storage medium determines the depth of the focal point within the storage medium. The internal surfaces of the lenses which define the air gap are preferably planar. The external surfaces of the lenses are aspheric to provide accurate focusing and positive spherical aberration. The air gap between the lenses may also be formed by curved internal surfaces, in which case it is best for the focus lens to have a concave internal surface. The apparatus and method of the present invention reduces the number of optical components required for an optical data reading/writing device.

Abstract: An optical system design method determines a specific optical group having a relatively high decentering aberration error sensitivity to parallel decentering and tilt decentering, and minimizes the absolute value of the decentering aberration coefficient of that group. In a first stage, an optical system group consisting of at least one lens surface is identified which presents a problem in production because of a relatively high centering error sensitivity. A second stage calculates decentering aberration using a decentering aberration coefficient of the group identified in the first stage, and compares a decentering aberration that is obtained by the calculation with actual decentering aberration.

Abstract: A lens system is constituted by a cemented lens made of anomalous dispersion glass for correcting the secondary spectrum of axial chromatic aberration, and a plastic lens having a temperature-compensating characteristic for compensating for defocusing upon change of the lens system with respect to temperature, thereby satisfactorily correcting color and compensating for temperature at the same time in a simple configuration. The imaging lens for image readout is constituted by eight sheets of lenses L.sub.1 to L.sub.8, in which the fourth lens L.sub.4 and the fifth lens L.sub.5 form a cemented lens made of anomalous dispersion glass, whereas the first lens L.sub.1 is a substantially powerless plastic lens having a temperature-compensating characteristic for compensating for defocusing upon change in the lens system with respect to temperature.

Abstract: There is disclosed a compact lens system having four injection-molded singlet lens elements with one of the singlet lens elements having a diffractive optical surface to control axial chromatic aberrations and another of the singlet lens elements having a flint-like plastic material to control lateral chromatic aberration. The lens system includes interdigitated flange features which provides interdigitated alignment between the lens elements. A plurality of light suppression elements are used to suppress stray light paths from reaching a detector array of the lens system. Moreover, the lens system includes an anti-aliasing surface on one of the lens elements for controlling aliasing effects.

Abstract: An optical access device for a moving optical data storage media having a flying lens near an outer surface of the media, and an objective lens spaced from the flying lens, with the flying lens and objective lens co-operating to substantially offset a variable range of negative spherical aberration occurring in the media by forming a positive spherical aberration which substantially cancels the negative spherical aberration.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element. The first optical element magnifies the projected source object and reflects a magnified virtual image of the projected source object to the beam splitter.

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: An optical system includes a housing having an axis of elongation, and a non-spherical window affixed to the housing. An optical corrector, preferably in the form of an aspherical strip of transparent material, is positioned adjacent to the curved inner surface of the window. The optical corrector is mounted on an optical corrector support, which is rotatable about the axis of elongation. An optical rain is positioned such the the optical corrector lies between the window and the optical train. The optical train includes at least one optical element operable to alter an optical ray incident thereon, and a gimbal upon which the at least one optical element is mounted. The gimbal is pivotable about a transverse axis perpendicular to the axis of elongation. The optical train is mounted on an optical train support, which is movable independently of the optical corrector support. A sensor is positioned to receive the optical ray passing sequentially through the window, the optical corrector, and the optical train.

Abstract: The present invention is an optical apparatus, e.g. an image display apparatus, which enables observation of a clear image at a wide field angle with substantially no reduction in the brightness of the observation image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The optical apparatus has an image display device (6), and an ocular optical system (7) for leading an image of the image display device (6) to an observer's eyeball (1). The ocular optical system (7) includes, in order from the image side, a third surface (5) which forms an entrance surface, a first surface (3) which forms both a reflecting surface and an exit surface, and a second surface (4) which forms a reflecting surface. The first to third surfaces (3 to 5) are integrally formed with a medium put therebetween which has a refractive index larger than 1.

Abstract: The invention provides a prism optical system which has an image-forming action and provides a clear yet substantially undistorted image at a wide field angle. In a prism optical system 5 comprising an aperture 1 and having an action on erecting an image formed by an objective, there are provided reflecting surfaces 31, 32, 33, 41, 42, and 43 for image inversion, each of which is constructed of a curved surface having a power, and is in an irrotationally symmetric plane shape having no rotationally symmetric axis both within and outside the surface, so that decentering aberration produced by reflection of light at the curved surfaces can be corrected.

Abstract: The invention relates to an image-forming optical system which is compact and light in weight with well corrected aberrations, and is suitable for use on an image display device designed to form no intermediate image, and an optical system. This optical system comprises a prism member and a diffraction optical element that are mutually decentered. The prism member comprises at least three juxtaposed optical surfaces, at least one of which is constructed of a curved surface. Between the optical surfaces, at least two reflections occur. Spaces between the optical surfaces arc filled with a medium having a refractive index greater than 1.

Abstract: A pair of compensation lenses which provide an adjustable amount of spherical aberration. Each compensation lens has an external surface and an internal surface. The internal surfaces face each other and define an air gap spacing between them. The external surfaces are preferably planar. The internal surfaces are purely aspheric and therefore have an absence of spherical power and an absence of spherical curvature. The amount of spherical aberration compensation is determined by adjusting an air gap spacing between the internal surfaces. The spherical aberration provided by the lenses can be negative, positive, or zero. For compensation of negative spherical aberration present when focusing light into a data storage medium, the compensation lenses should provide positive spherical aberration. The absence of spherical power characteristic of the compensation lenses allows them to be located far from an objective lens which requires spherical aberration compensation.

Abstract: Methods and apparatus for enhancing the performance of reflective LCD systems. The high-contrast color-splitting prism system utilizes a "double-pass" prism assembly. Polarized light enters the prism assembly, is color-split and is emitted as separate colors to reflective imagers which reflect each color in accord with a desired image. The reflected light is passed, once again, through the prism assembly where the separate colors converge and the convergent light is emitted to a projection lens for display of the image on a screen. At least one zero-incidence waveplate compensator is positioned between one reflective imager and the prism assembly. The waveplate compensator effectively decreases the unwanted polarized light entering the prism assembly for the second pass-through, thereby increases the polarization purity of the light that is emitted from the prism assembly to the projection lens to yield a high-contrast projection image.

Abstract: The exposure projection apparatus includes an illumination system which illuminates a mask with a light beam, and a optical projection system which projects the image of a pattern formed on the mask onto a substrate. The optical projection system includes a first barrel which holds a plurality of optical elements, at least three second barrels, each holding at least one optical element disposed between the mask and the first barrel, so that the coma, astigmatism, and distortion of the optical projection system can be adjusted, and a first optical element which is disposed between the substrate and the first barrel so that either the spherical aberration or curvature of field of the optical projection system, or both, can be adjusted.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element. The first optical element magnifies the projected source object and reflects a magnified virtual image of the projected source object to the beam splitter.

Abstract: A compact image-forming optical apparatus which is free from moire fringes and capable of providing an aberration-free, clear image of minimal distortion even at a wide field angle. The image-forming optical apparatus has an objective optical system (104) and an electronic image pickup device (108). The objective optical system (104) has at least one reflecting surface (106, 107) decentered such that the whole surface is tilted with respect to the axial principal ray. The reflecting surface has a rotationally asymmetric surface configuration that corrects rotationally asymmetric decentration aberrations caused by decentration. A low-pass member (103) is disposed in the vicinity of a pupil plane (101) closer to the object than the reflecting surface. The low-pass member cuts off a high-frequency component concerning the object image in a bundle of rays led to the electronic image pickup device (108).

Abstract: A compact image display apparatus having a wide exit pupil diameter, which enables observation of an image that is flat and clear as far as the edges of visual field at a field angle of 40.degree. or more. The apparatus includes an image display device (8) for displaying an image, a relay optical system (7) for relaying the image to form a relay image, and an ocular optical system having a reflecting surface (2) that bends a bundle of light rays emanating from the relay optical system (7) and forming an exit pupil (1) of the relay image. The ocular optical system has an entrance-side optical surface (6) provided in an optical path extending from the relay optical system (7) to the reflecting surface (2), and an exit-side optical surface (5) provided in an optical path along which the ray bundle bent by the reflecting surface travels to reach the exit pupil (1) and having a power different from that of the entrance-side optical surface (6).

Abstract: An optical system capable of correcting aberrations due to three-dimensional decentration by using a rotationally asymmetric surface having no plane of symmetry. The optical system includes, from the ray bundle entrance sides, a first surface (3) serving as both a first transmitting surface and a second reflecting surfaces a second surface (4) as a first reflecting surfaces and a third surface (5) as a second transmitting surface. The space between these surfaces is filled with a medium having a refractive index larger than 1. The first surface (3) is a three-dimensional surface having no plane of symmetry.

Abstract: A virtual image display system is provided which is made thinner through the use of an immersed beam splitter, and in one embodiment, total internal reflection. The display system includes an imaging surface on which a source object is formed, a first optical element having a reflective function and a magnification function, a second optical element having a magnification function and an immersed beam splitting element positioned between the first and second optical elements, the immersed beam splitting element including a beam splitter surrounded by an optically transparent material having a refractive index greater than that of air. An illumination source projects the source object formed at the imaging surface through the optically transparent material to the beam splitter. The beam splitter reflects the projected source object to the first optical element.

Abstract: A full color display optical system with chromatic aberration correction. The system includes a wide spectral band image source such as a cathode ray tube or Ferroelectric liquid crystal array, a field sequential Red-Green-Blue shutter, and an optical module for projection. The optical module corrects longitudinal chromatic aberration and higher order monochromatic and chromatic aberrations. Lateral chromatic aberration and chromatic distortion are compensated electronically by the color sequential shutter and the image source with a pre-distorted image.

Abstract: The present invention is an optical apparatus, e.g. an image display apparatus, which enables observation of a clear image at a wide field angle with substantially no reduction in the brightness of the observation image, and which is extremely small in size and light in weight and hence unlikely to cause the observer to be fatigued. The optical apparatus has an image display device (6), and an ocular optical system (7) for leading an image of the image display device (6) to an observer's eyeball (1). The ocular optical system (7) includes, in order from the image side, a third surface (5) which forms an entrance surface, a first surface (3) which forms both a reflecting surface and an exit surface, and a second surface (4) which forms a reflecting surface. The first to third surfaces (3 to 5) are integrally formed with a medium put therebetween which has a refractive index larger than 1.

Abstract: A display system employs rear projection to a curved, translucent display or image screen. A lens between the projecting device and the display screen eliminates or reduces distortion by altering a convergence of the projected image, transforming the projected image from diverging to converging for a convex rear projection screen surface or further diverging the image for a concave rear projection screen surface. A lightweight and economical Fresnel lens may be employed for this purpose.

Abstract: In a projection exposure apparatus, two plane-parallel plates, which are equal in thickness and refractive index, are interposed between a projection optical system and a wafer. By tilting these two plane-parallel plates at the same angle in opposite directions with respect to the optical axis of the optical system by means of an adjusting device, astigmatism caused in the optical system by exposure is corrected. The amount of astigmatism is calculated by a calculating device based on the amount of light incident on the optical system per unit of time which is obtained according to the output of a light amount sensor.

Abstract: An optical system is provided that has an enclosure which is substantially filled with a fluid. The enclosure also has an aperture for receiving an electromagnetic wave that is altered by an optical component contained in the enclosure. The enclosure also has an aperture mask and blocker that are at least partially immersed in the fluid.

Abstract: A beam shaping device for a laser device is provided. The laser device has a beam with a first beam quality factor M.sub.x.sup.2 in a first direction, and a second beam quality factor M.sub.y.sup.2 in an orthogonal direction. The beam shaping device includes at least one reflecting surface diverting at least a first part of the beam in order to reconfigure at least one of the first and second beam qualities M.sub.x.sup.2 and M.sub.y.sup.2.

Abstract: An objective lens system of a quite simple construction with fewer lenses cyomplying with a continuous variation in thickness of the disk. The system records and reproduces information on a high-density and mass storage optical information medium while providing excellent performance. The system comprises a single positive lens element, a positive objective lens element and a disk arranged in that sequence from the side of a light source, in which the single positive lens is moved on an optical axis to improve the aberration that has increased as a result of a variation in thickness of the disk and the objective lens is moved by a slight distance on the optical axis to be in-focus state in response to the movement of the image point resulting from the variation in the thickness of the disk.

Abstract: A Michelson-type interferometer which includes apparatus for producing a suitable collimated interferometer input beam; a beam splitter and recombiner for first splitting the input beam into two beams which have components arranged to travel along parallel forward paths and then to recombine them into a single output beam as they are returned along reverse paths to the beam splitter and recombiner; an OPD scanner for scanning the optical path difference between the two split beams travelling along said paths while substantially maintaining the parallelism between the components, and a beam reverser common to the parallel beam components for reversing their direction of travel along the reverse paths and returning them for recombination into the single output beam at the beam splitter and recombiner.

Abstract: A head- or face-mounted image display apparatus having compact and wide-field ocular optical systems designed to form readily fusible virtual images. When ocular optical systems having curvature of field are used for observer's right and left eyes, right and left virtual images (13R and 13L) are curved. The right and left ocular optical systems (11R and 11L) having curvature of field are disposed such that the positions of right and left virtual image surfaces are approximately coincident with each other in an area where the right and left virtual image surfaces overlap each other. With this arrangement, a wide field can be ensured, and moreover, the right and left virtual images can be readily fused because the right and left image surface positions are approximately coincident with each other in an area where the right and left image surfaces overlap each other. Accordingly, the user can perform observation with both eyes without fatigue.

Abstract: An improved particle lens has an axis that is shifted to follow the central ray of the beam as it is deflected through the lens creating, in effect, a variable curvilinear optical axis for the lens and introducing aberrations depending on the object size and the distance off the lens symmetry axis. These aberrations are corrected by a set of wire pairs perpendicular to the system axis to add a gradient of the z-component of the magnetic field by which aberrations are generated of the same type but opposite direction as those inherent in the system.

Abstract: Analytical optical system design optimization implements an optical material selection module (302), a thin lens power calculation module (304), a prescription module (306), a figure of merit determination module (308), a bending adjustment module (310), and a focal length scaling module (312). The optical material selection module (302) selects a set of optical materials that are appropriate for use together in an optical system using the dispersion coefficients of the materials. Potential optical designs are screened according to thin lens power criteria. For each design with acceptable power distribution, a lens prescription is arranged and thickness is added to each lens by the prescription module (306) to provide a thick lens assembly. Designs can then be analyzed according to a figure of merit that evidences optical system performance by the figure of merit determination module (308). In an exemplary embodiment the polychromatic RMS spot radius for each design is analyzed.