Abstract: A method for designing an optical system for providing reliable, robust and successful realization of a distortion variation function is presented. In a preferred embodiment, the proposed distortion variation optical system includes at least two non-symmetrical elements, which are moving in the transverse direction. The proposed freeform lens contains two transmissive refractive surfaces. The freeform elements designed with this method have preferably a flat surface and a non-symmetrical freeform surface. The two plano-surfaces are preferably made to face each other, so that a miniature camera can be offered. The value of the non-symmetrical freeform surface is used to produce variable optical power when the two freeform elements undergo a relative movement in the vertical direction. Using this method, an optical system with an active distortion, smaller form factor, and better imaging quality can be obtained.

Abstract: Provided is a metalens including a first metasurface including a plurality of first nanostructures disposed based on a first shape distribution, and a second metasurface spaced apart from the first metasurface at a distance greater than a central wavelength of a predetermined wavelength band, the second metasurface including a plurality of second nanostructures disposed based on a second shape distribution, wherein the metalens provides chromatic aberration for light in the predetermined wavelength band.

Abstract: A puddle lamp device configured for displaying an image may include a housing; and an illumination system lens, an image film, and a plurality of image forming system lenses embedded in the housing, and sequentially arranged in one direction thereof, in which at least one image forming system lens among the plurality of image forming system lenses is made of a cycloolefin polymer (COP) material, and the present invention may make an image to be displayed clearer while performing a function of a puddle lamp, thereby improving the resolution.

Abstract: A freeform surface off-axial three-mirror imaging system comprising a primary mirror, a secondary mirror, a tertiary mirror, and an image sensor. Each reflective surface of the primary mirror, the secondary mirror, and the tertiary mirror is an xy polynomial freeform surface. A field angle of the freeform surface off-axial three-mirror imaging system is larger than or equal to 60°×1°. An F-number of the freeform surface off-axial three-mirror imaging system is less than or equal to 2.5.

Abstract: The present application discloses an imaging camera, including: a lens holder with an aperture; a first lens unit, a gasket, and a second lens unit arranged in an order from an object side of the imaging camera to an image side of the imaging camera. The second lens unit includes a main area for imaging, a supporting area extending from an edge of the main area, and a recess formed in an object side surface of the supporting area. The gasket includes a gasket body and a protrusion extending from the gasket body toward the recess, the protrusion being at least partially received in the recess. By virtue of the complementary configuration, the relationship between the second lens unit and the gasket becomes easier.

Abstract: A prism optical system has an optical element that includes, a first surface that defines a transmitting surface as an entrance surface and an internal reflecting surface as well, a second surface that defines an internal reflecting surface in opposition to the first surface, a third surface that defines an internal reflecting surface in opposition to the first surface and adjacent to the second surface, a fourth surface that defines an internal reflecting surface in opposition to the first surface and adjacent to the third surface and an internal reflecting surface closest to the image plane as well, and a fifth surface that defines a transmitting surface adjacent to the first surface and in opposition to the fourth surface; the fourth surface is defined by a rotationally asymmetric surface having a negative power in the Y-Z plane and a positive power in the X-direction perpendicular to the Y-Z plane.

Abstract: A head mounted display device includes a scanning section that forms a scan image by scanning a light beam emitted from a light source, a light guiding optical system that guides the light beam emitted from the scanning section, and a deflection member that deflects the light beam guided by the light guiding optical system toward the eye. The light guiding optical system includes an optical correction system in which a first light path length of a light beam from the scanning section to a first end portion on a nose side of the deflection member is longer than a second light path length of a light beam from the scanning section to a second end portion on an ear side of the deflection member, and that corrects scanning distortion in the scan image which cause a virtual image to have different magnifications in a horizontal direction.

Abstract: Side illumination is combined with scanning interferometry to provide a means for measuring with a single data-acquisition scan surfaces that contain sections suitable for interferometric processing as well as sections that are not suitable because of lack of fringes produced by the measurement. In the sections where no fringes are produced, the irradiance detected during the scan is processed using a depth-from-focus mapping method to yield a corresponding measurement. The result is a complete profilometric measurement of the sample surface with a single scan. In addition, by increasing sample irradiance through side illumination, the structural features of the sample become markedly more visible than when illuminated only by the object beam of the interferometer, which greatly facilitates finding focus and identifying regions of interest for the measurement.

Abstract: To accurately position multiple tomographic image. An image processing apparatus includes a detecting unit configured to detect motion of an eye in a plurality of polarization-sensitive tomographic images, based on a predetermined region extracted from the plurality of polarization-sensitive tomographic images of the eye, and a positioning unit configured to position a plurality of tomographic luminance images corresponding to the plurality of polarization-sensitive tomographic images, based on the detected movement.

Abstract: A method and a system are for compensating optical aberrations in a telescope. The method is applicable to a telescope wherein the element for receiving a primary beam is an image acquisition device (3), and involves using an algorithm without an image processing sensor for: a) detecting optical aberrations affecting the primary focus, by analyzing the images acquired by the image acquisition device (3), and b) calculating and generating first positional correction values, by processing the detected optical aberration values. The method also includes a step c) consisting in moving, in a controlled manner, the image acquisition device (3), applying suitable control signals generated from the first positional correction values. The system is suitable for implementing the proposed method.

Abstract: A tiled head-mounted display device comprises an optical component including a plurality of prisms with free-form surfaces, and a display component including a plurality of micro-displays (6), wherein the number of the micro-displays (6) and the number of the prisms with free-form surfaces is identical, and each prism with free-form surfaces and the corresponding micro-display (6) constitute a display channel. Each prism is a wedge prism including a first surface (2), a second surface (3) and a third surface (4). The exit pupil planes of each display channel are coincident, thus avoiding pupil aberration and keeping exit pupil diameter and eye clearance same as a single ocular. There is no resolution variance throughout the entire field of view, thus preventing extra trapezoid distortion. The tiled head-mounted display device is compact and lightweight, and provides wide field of view and high resolution.

Abstract: A plastic lens, comprising: a first edge section having a first outer circumferential edge surface formed substantially parallel to an optical axis of the plastic lens; and a second edge section having a second outer circumferential edge surface formed so as to have a step with respect to the first outer circumferential edge surface, wherein the first outer circumferential edge surface is not coated with a black coating material that suppresses internal reflection of light, and at least a portion of the second outer circumferential edge surface is coated with the black coating material that suppresses internal reflection of light.

Abstract: An optical element according to the present invention includes: an optical surface at a center portion thereof; a spacer section having a predetermined thickness on an outer circumference side of the optical surface; a support plate including one or a plurality of through holes penetrating the optical surface, inside a transparent resin material; and a penetrating portion and/or a concave portion for releasing the resin material when forming resin, in a further outer peripheral portion of the support plate.

Abstract: A spherical aberration corrector is offered which permits a correction of deviation of the circularity of at least one of an image and a diffraction pattern and a correction of on-axis aberrations to be carried out independently. The spherical aberration corrector (100) is for use with a charged particle beam instrument (1) for obtaining the image and the diffraction pattern and has a hexapole field generating portion (110) for producing plural stages of hexapole fields, an octopole field superimposing portion (120) for superimposing an octopole on at least one of the plural stages of hexapole fields to correct deviation of the circularity of at least one of the image and diffraction pattern, and a deflection portion (130) for deflecting a charged particle beam.

Abstract: An image blur correction device includes a lens unit having at least one lens and rotationally moving in a first direction which is a rotation direction of a first fulcrum axis and in a second direction which is a rotation direction of a second fulcrum axis relative to an outer casing, a first driving motor which causes the lens unit to pivot in the first direction, and a second driving motor which causes the lens unit to pivot in the second direction. An auxiliary axis is disposed opposite to the first driving motor with interposing of the lens unit, the lens unit pivots in the first direction and in the second direction by the rotation of output axes of the first and second driving motors, and each output axis is rotatably supported by a pair of first bearings and each auxiliary axis is rotatably supported by a second bearing.

Abstract: A Head Up Display can be utilized to find light from an energy source. The Head Up Display includes a first waveguide having a first input coupler and a first output coupler. The Head Up Display can also include a second waveguide having a second input coupler and a second output coupler. The first waveguide has a first major surface and the second waveguide has a second major surface, which are disposed approximately parallel to each other. The first waveguide and the second waveguide are positioned as a combiner and allowing viewing an outside feed and information from an image source. The first input coupler diffracts light in the first field of view into the first waveguide and light in a second field of view reaches the second input coupler and is diffracted into the second waveguide.

Abstract: An eyepiece for a HMD includes a waveguide, an ambient light polarizer, and a wire grid polarizer with a diffraction lens having a lens function patterned into the wire grid polarizer. Polarized image light is guided between eye-ward and ambient sides of the waveguide from a display source to a viewing region of the waveguide where the polarized image light is directed out of the waveguide through the eye-ward side. The viewing region passes ambient light incident on the ambient side through to the eye-ward side. The ambient light polarizer is disposed adjacent to the ambient side to polarize the ambient light into polarized ambient light having a second polarization orthogonal to the first polarization. The wire grid polarizer is disposed adjacent to the eye-ward side along the viewing region. The wire grid polarizer is oriented to applying the lens function to the polarized image light via diffraction.

Abstract: Units which respectively acquire information on an aberration generated by a display optical system and information on an aberration generated by a vision correction optical system used by an observer are arranged. Aberration correction is executed based on the two aberrations. An aberration generated by a combination of the display optical system and the vision correction optical system used by the observer can be appropriately corrected for each observer.

Abstract: Fluorescence is generated from an irradiated point on an inspection surface of a sample and the fluorescence is collected by an objective lens. Here, because of the magnification chromatic aberration of the objective lens, the fluorescence going out from the objective lens travels along a path shifted from the irradiation light and changed substantially into a non-scan light by a galvano-scanner. The fluorescence passes through a dichroic mirror into a plane-parallel plate after light of unnecessary wavelength is removed by a filter. The plane-parallel plate is driven in synchronization with the galvano-scanner by a computer and corrects the shift and inclination of the optical axis generated by the magnification chromatic aberration of the objective lens. Then, the fluorescence forms an image of the irradiation point of the inspection surface of the sample on a pin hole of a pin hole plate by using a collective lens.

Abstract: An opto-mechanical switch produces different optical paths from two optical path sections out of a plurality of optical path sections that are oriented in different spatial directions. The switch has an optical component on which one end of each optical path section impinges, and which is adapted to be moved linearly in a direction of movement at right angles to the optical path sections between different switching positions, in which it selectively couples different optical path sections optically with each other. Further provided is a measuring system for the analysis of fluids, having such an opto-mechanical switch.

Abstract: A projection lens for projecting images with high degrees of image offset while limiting the physical offset of the projection lens elements. The projection lens arrangement limits the displacement of the optical elements relative to the optical axis of the display panel and enables a very thin, efficient projector.

Abstract: A space telescope system includes, but is not limited to, a support platform configured to orbit astronomical object, a plurality of mirrors mounted to the support platform and spaced apart from one another, the plurality of mirrors being configured to reflect a plurality of focused beams, and a focal plane image combiner positioned to intersect the plurality of focused beams and configured to combine the plurality of focused beams to form a composite image.

Abstract: A luminous flux branching element includes a transparent base member arranged diagonally to an optical axis and having an incidence plane and an emission plane parallel to each other. Incident light from the incidence plane is split into a main luminous flux emitted from an emission position on the emission plane and a branched luminous flux emitted from a branch position apart from the emission position and having a smaller light quantity than of the main luminous flux. A reflecting member is arranged on the incidence plane to cause the incidence plane to reflect reflected light from the emission plane. A non-coat region in which antireflection-treatment is not performed is formed in a region of the emission plane where the incident light from the incidence plane is reached, and antireflection-treatment is performed in the emission plane excluding the non-coat region and the incidence plane.

Abstract: A system (10) for multispectral imaging includes a first optical filter (24, 20) having at least two passbands disposed in different spatial positions on the first optical filter, a second optical filter (20, 24) having another at least two passbands, and processor (32) adapted to identify an intensity of light in the at least two passband of the second optical filter.

Abstract: An array of light valves switch light by enabling and disabling total internal reflection (TIR) on a surface of the light valve. The disabling of the TIR is accomplished by putting another optical element in contact with the surface and then diffusing or changing the direction of the light. The mechanical mechanism to move the optical element is a simple one in that it only moves the optical element a small distance to change the valve from a first position to a second position.

Abstract: A confocal scanning microscope including: an objective system (second objective lens 23 and objective lens 24) illuminating a sample SA with illumination light; a scanning mechanism 31 scanning the sample SA to obtain an intensity signal; and a scanning optical system 32 provided between the scanning mechanism and the objective system. The scanning optical system composed of, in order from the scanning mechanism side, a first positive lens group G1, a second negative lens group G2, and a third positive lens group G3. The third lens group has two chromatic aberration correction portions each formed by a positive lens and a negative lens or negative lens and positive lens. Glass materials are selected such that one performs chromatization and the other performs achromatization, thereby providing a confocal scanning microscope capable of correcting lateral chromatic aberration generated in the objective system in the specific wavelength region by the scanning optical system.

Abstract: A laser scanning microscope is disclosed that combines light from first and second scanning optical systems onto a common optical path using a beam combiner. A first plane-parallel transparent plate and a beam combiner are positioned on a support that may be moved relative to the common optical path. The first plane-parallel transparent plate has an optical thickness equal to the optical thickness of the beam combiner and is oriented with its surface normal lying substantially parallel with the surface normal of the beam combiner. An astigmatism-correcting optical element is provided on the common optical path, with the astigmatism-correcting optical element generating astigmatism that is equal in magnitude, but different in direction by 90 degrees, to the astigmatism generated by non-collimated light that is transmitted through the beam combiner. When the support is repositioned, spherical aberration in various light paths is maintained constant so that it may be easily corrected.

Abstract: A head-mounted device mounted on a wearer's head has a first pressing unit to press against the wearer's head from a position of his/her medulla, a second pressing unit to press against the wearer's head in an opposite direction to a pressing direction of the first pressing unit, and a mounting unit to mount the head-mounted device on the wearer's head by adjusting at least one of the first pressing unit and the second pressing unit.

Abstract: Embodiments of the present invention are directed to beamsplitters that include optical elements to correct for beam offset. In one embodiment, a beamsplitter includes a first plate having two approximately parallel and opposing planar surfaces and a partially reflective layer coating one of the planar surfaces, and a compensator plate having two approximately parallel and opposing planar surfaces. The compensator plate is positioned so that an incident beam of light passing through the compensator plate acquires a first beam offset. Subsequently, the incident beam of light with the first beam offset passing through the first plate is split into a reflected beam and a transmitted beam by the partially reflective layer where the transmitted beam has a second beam offset that substantially cancels the first beam offset such that the transmitted beam is approximately parallel to and aligned with the incident beam.

Abstract: An optical assembly uses a plastic prism with one flat surface and a collimating lens optic to provide the capability of imaging a color micro-display to the eye. The collimating optic and flat prism surface can allow for aberration-free diopter adjustment and an image with very low-magnitude, nearly-symmetric distortion. The collimating optic can also provide environmental protection of the prism involving an optical plastic device. The input illumination from the micro-display enters the prism, is reflected two times within the prism, exits the prism, and passes through the collimating optic before being viewed by the eye. Such an optical assembly can provide a field of view with eye-relief and exit pupil when viewing a full-color micro-display.

Abstract: A method for optimizing cost and performance in a lens assembly is disclosed. The method relaxes the constraints of optically correcting lateral chromatic aberration and distortion on the lens assembly and instead electronically corrects for lateral chromatic aberration and distortion. As a result the lens assembly transmissivity and MTF improve dramatically and other aberrations are reduced as a result of re-optimizing the lens assembly merit function. The cost and volume of the lens assembly are reduced as well. The optimized lens assembly could be used in rear or front projection display devices as a well as image acquisition devices.

Abstract: A see-through head-mounted optical apparatus for a viewer has at least one display module, each display module having a display energizable to form an image and a positive field lens optically coupled to the surface of the display and disposed to direct imaged light from the display toward a first surface of a prism. A curved reflector element is in the path of the imaged light through the prism and disposed at a second surface of the prism, opposite the first surface. The curved reflector element has a refractive surface and a curved reflective surface disposed to collimate imaged light received from the display and direct this light toward a beam splitter that is disposed within the prism and that is at an oblique angle to the collimated reflected light. The beam splitter redirects the incident collimated reflected light through the prism to form an entrance pupil for the viewer.

Abstract: A system (10) for multispectral imaging includes a first optical filter (24) having at least two passbands disposed in different spatial positions on the first optical filter, a second optical filter (20) having another at least two passbands, and processor (32) adapted to identify an intensity of light in the at least two passband of the second optical filter (20).

Abstract: Providing a sighting device having a simple structure, being easy to manufacture and free from parallax. A sighting device comprises, in order from a target object side, a positive meniscus lens having a convex surface facing the target object and a negative meniscus lens having a convex surface facing the target object, wherein the surface of said positive meniscus lens that faces away from said target object or the surface of said negative meniscus lens that faces toward said target object is adapted to constitute a semi-transparent reflection surface or a wavelength selective reflection surface, and a point source is provided at a focal point of a catadioptric optical system constituted by said semi-transparent reflection surface or said wavelength selective reflection surface and a refracting surface of the negative meniscus lens having with the convex surface facing said target object, the refracting surface facing away from said target object side.

Abstract: An optical concentrator is disclosed which includes an imaging, aplanatic optical element having a front surface with a one-way light admitting portion, a back surface with a reflective portion, and an interior region of refractive material disposed between the front and backs surfaces.

Abstract: An imaging assembly for an image sensor may include a lens, a transparent substrate and two aspherical optical coatings on each side of the substrate. The imaging assembly can also incorporate an opaque coating with an opening in-line with the lens to form an aperture, an anti-reflection coating, and an infrared filter coating.

Abstract: An absorptive coating is in contact with an optical beam splitter such that a signal beam and a reference beam incident on the beam splitter from opposite sides are can be combined to produce two interference beams having a phase difference of about ? 2 .

Abstract: A beam delivery system of a projection exposure system comprises a laser generating a beam of laser light from a plurality of longitudinal laser modes in a cavity, wherein light generated by a single longitudinal laser mode has an average line width ?lat, wherein the laser light of the beam has, at each of respective lateral positions of the beam, a second line width ?lat corresponding to lateral laser modes, and wherein the laser light of the beam has, when averaged over a whole cross section thereof, a line width ?b corresponding to plural lateral laser modes, and wherein ?m<?lat<?b, and wherein an optical delay apparatus disposed in the beam provides an optical path difference ?l, wherein 0.8 · ? 0 2 ( 2 · ? ? ? ? l ) < ? ? ? l < 1.8 · ? 0 2 ( 2 · ? ? ? ? l ) , wherein ?0 is an average wavelength of the light of the first beam of laser light, and ??lat represents the second line width.

Abstract: A beam blocking and combining optic comprising a wedged optically transparent substrate with a hard dielectric coating applied to a beam combining side of the substrate. The coating has a high reflectance at a laser wavelength and high transmittance at visible wavelengths. The single optical component can combine laser beams into a viewing path and act as a laser safety filter to protect the viewer from reflected laser radiation while providing good color balance and very low astigmatism in the viewing path and very low astigmatism in the reflected laser beam.

Abstract: A projection optical system including a projection lens, a first mirror that reflects a light from the projection lens, and a second mirror that widens an angle of a light from the first mirror by reflecting the light projects a light modulated according to an image signal from an optical engine unit. A third mirror reflects a light from the projection optical system. A screen transmits a light from the third mirror. An optical axis of the projection lens substantially matches an optical axis of the second mirror, and the light from the optical engine unit is shifted to a specific side from the optical axis of the projection lens.

Abstract: A digital image projector includes a light assembly configured to project light along a light path from at least one laser array light source, the projected light having an overlapping far field illumination in a far field illumination portion of the light path; a temporally varying optical phase shifting device configured to be in the light path; an optical integrator configured to be in the light path; a spatial light modulator located downstream of the temporally varying optical phase shifting device and the optical integrator in the light path, the spatial light modulator configured to be located in the far field illumination portion of the light path; and projection optics located downstream of the spatial light modulator in the light path, the projection optics configured to direct substantially speckle free light from the spatial light modulator toward a display surface.

Abstract: Embodiments of the present invention are directed to beamsplitters that include optical elements to correct for beam offset. In one embodiment, a beamsplitter includes a first plate having two approximately parallel and opposing planar surfaces and a partially reflective layer coating one of the planar surfaces, and a compensator plate having two approximately parallel and opposing planar surfaces. The compensator plate is positioned so that an incident beam of light passing through the compensator plate acquires a first beam offset. Subsequently, the incident beam of light with the first beam offset passing through the first plate is split into a reflected beam and a transmitted beam by the partially reflective layer where the transmitted beam has a second beam offset that substantially cancels the first beam offset such that the transmitted beam is approximately parallel to and aligned with the incident beam.

Abstract: An exemplary optical hybrid includes a 50/50 un-polarized beam splitter, a folding prism, a beam shifter, a spacer and a phase shifter such that from an input S-beam (signal) and an L-beam (reference), four outputs, S+L, S?L, S+jL and S?jL, are produced. The phase difference between the two components of each output beam produced by the S and L beams in the optical hybrid is ?+0, ?+90, ?+180, or ?+270 degrees, where ? is the phase difference of the signal beam with respect to the reference beam. In an alternative embodiment, the phase difference between the two components of each output beam produced by the S and L beams in the optical hybrid is ?+0, ?+X, ?+180, or ?+180+X degrees, where X is an arbitrary number of degrees greater than 0 and smaller than 180.

Abstract: An aberration correction apparatus comprising a liquid crystal device which includes a first electrode layer that is formed with regions divided concentrically, a second electrode layer that is formed with regions divided concentrically, and a liquid crystal that is sandwiched in between the first electrode layer and the second electrode layer, and which transmits an incident light beam therethrough, an objective lens which condenses the light beam transmitted through the liquid crystal device, and a liquid-crystal-device drive circuit which drives the liquid crystal device, wherein the liquid-crystal-device drive circuit impresses a potential which belongs to a predetermined region included in a liquid crystal characteristic that is a relationship between potentials impressed on the respective electrode layers sandwiching in the liquid crystal therebetween and a phase change magnitude of the light beam transmitted through the liquid crystal, on the concentric regions formed in the first electrode layer, and

Abstract: An illumination system including a coherent light source and a speckle-reducing module is provided. The coherent light source is adopted for providing a light beam. The speckle-reducing module is disposed at an optical path of the light beam. The speckle-reducing module includes a rotator, a carrier and an optical path adjusting member. The rotator is adopted for rotating on a reference plane about a spindle axis passing through the rotator. The spindle axis is substantially perpendicular to the reference plane. The carrier is disposed at the rotator. The optical path adjusting member is disposed at the carrier and at the optical path of the light beam. The optical path adjusting member has an incident surface inclined at an angle with respect to the reference plane.

Abstract: A software product includes instructions stored on computer-readable media, that when executed by a computer, perform steps for optimizing an optical system design and a digital system design. The instructions are for simulating an optical model of the optical system design, simulating a digital model of the digital system design, analyzing simulated output of the optical model and simulated output of the digital model, to produce a score, modifying the optical model and the digital model, based upon the score, controlling re-execution of the instructions for simulating the optical model, the instructions for simulating the digital model, the instructions for analyzing and the instructions for modifying to produce an optimized optical model and an optimized digital model, and outputting predicted performance of the optimized optical and digital models.

Abstract: A system and method for correcting optical aberrations in optical devices, such as wide-field microscopes, optical tweezers and optical media devices, such as DVD drives. The system uses adaptive optics to correct optical aberrations, such as spherical and space-variant aberrations. Spherical aberrations can be corrected using one adaptive optical elements and space-variant aberrations can be corrected using numerous adaptive optical elements in tandem. The adaptive optical elements may be of several types, such as a liquid lenses, deformable membrane mirrors or various liquid crystal phase and amplitude modulators. Adaptive optics can also be used to simultaneously shift the focus of the optical device and correct optical aberrations.

Abstract: A liquid crystal element for correcting wave aberration included in an optical disc apparatus, is controlled by a liquid crystal element control unit which has a memory portion that stores information about a variation with time of orientation direction of liquid crystal in the case where a voltage is applied to the liquid crystal, with respect to at least one type of voltage value. The liquid crystal element control unit has a drive voltage deciding portion that obtains time period after a predetermined drive voltage is applied to the liquid crystal element until a reproduced signal obtained by processing an electric signal converted by the light detecting unit becomes optimal, and decides a drive voltage to be applied to the liquid crystal element based on the obtained time period, the information stored in the memory portion, and the predetermined drive voltage.

Abstract: An optical device includes an elongated tube configured for insertion into a body and optical members located in the tube. The optical members are configured to have an optical invariant-to-clear aperture semidiameter ratio greater than about 0.05 and an optical path difference less than about a value of the optical invariant divided by at least 250 times a midrange wavelength in a spectral range from about 435.8 nm to about 656.3 nm, and are preferably formed of an extraordinary dispersion optical material. A method includes conducting polychromatic light through at least one optical member located in an elongated tube configured for insertion into a body, where the optical members have an optical invariant-to-clear aperture semidiameter ratio greater than about 0.05 and an optical path difference less than about a value of an optical invariant divided by at least 250 times the midrange wavelength from about 435.8 to about 656.3 nm.

Abstract: In one form, an imaging system comprises an imager that forms an image of an object in a field of view, a rotationally symmetric lens assembly disposed between the imager and the object, and an equalizer. The rotationally symmetric lens assembly provides increased collection efficiency for a given depth of field, whereby the rotationally symmetric lens assembly causes aberration, compared to a well-focused lens. The rotationally symmetric lens assembly comprises a front negative lens, a rear positive lens, and an aperture positioned between the front and rear lenses. The equalizer, which is connected to the imager, receives image data and at least partially compensates for the aberration caused by the rotationally symmetric lens assembly.