Showing papers on "Lens (optics) published in 2009"

Capturing and processing of images using monolithic camera array with heterogeneous imagers

Abstract: Systems and methods for implementing array cameras configured to perform super- resolution processing to generate higher resolution super-resolved images using a plurality of captured images and lens stack arrays that can be utilized in array cameras are disclosed. Lens stack arrays in accordance with many embodiments of the invention include lens elements formed on substrates separated by spacers, where the lens elements, substrates and spacers are configured to form a plurality of optical channels, at least one aperture located within each optical channel, at least one spectral filter located within each optical channel, where each spectral filter is configured to pass a specific spectral band of light, and light blocking materials located within the lens stack array to optically isolate the optical channels.

Planar lenses based on nanoscale slit arrays in a metallic film.

Abstract: We experimentally demonstrate planar lenses based on nanoscale slit arrays in a metallic film. Our lens structures consist of optically thick gold films with micron-size arrays of closely spaced, nanoscale slits of varying widths milled using a focused ion beam. We find excellent agreement between electromagnetic simulations of the design and confocal measurements on manufactured structures. We provide guidelines for lens design and show how actual lens behavior deviates from simple theory.

System and method for measuring irregular objects with a single camera

Abstract: An optical system for measuring an irregularly shaped object includes a dimensioning station having a base, a first wall extending from the base, and a second wall extending from the base. A collimated light is passed from each of first and second collimated light sources arranged generally parallel to the base, illuminating the first and second walls and defining first and second shadows, respectively. A camera is arranged to obtain image data representing each of the first and second shadows. The system is configured to collect the image data for determining at least one dimension of an object from each of the first and second shadows. Each of the first and second collimated light sources may be a light with a collimating lens arranged between the light and the respective wall. The light source may be an LED and the collimating lens may be a collimating Fresnel lens.

Near-field focusing and magnification through self-assembled nanoscale spherical lenses

Abstract: The performance of a light microscope is intrinsically constrained by the Abbe diffraction limit. No matter how close to optical perfection it is, an imaging system cannot resolve two objects that are beyond this natural limit, which is dependent on the wavelength of the observed light and its angular distribution. Several methods have been devised to beat the diffraction limit, but these have generally required esoteric excitation schemes, so remain impractical. Lee et al. are working on a new way of beating the limit, using nanoscale spherical lenses that self-assemble by bottom-up integration of cup-shaped organic molecules called calixarenes. Lenses produced in this way have very short focal lengths that can generate near-field magnification beyond the diffraction limit, enabling the resolution of features of the order of 200 nm. The lenses can be placed at will on a surface and, among other things, can be used to reduce the size of deep-ultraviolet lithography features. Cup-shaped molecules of calix[4]hydroquinone self-assemble on a surface into a lens shape; these lenses are shown to generate near-field magnification beyond the diffraction limit, enabling the resolution of features of the order of 200 nanometres. Such spherical nanolenses provide new pathways for lens-based near-field focusing and high-resolution optical imaging at very low intensities, which are useful for, among other things, bio-imaging and near-field lithography. It is well known that a lens-based far-field optical microscope cannot resolve two objects beyond Abbe’s diffraction limit. Recently, it has been demonstrated that this limit can be overcome by lensing effects driven by surface-plasmon excitation1,2,3, and by fluorescence microscopy driven by molecular excitation4. However, the resolution obtained using geometrical lens-based optics without such excitation schemes remains limited by Abbe’s law even when using the immersion technique5, which enhances the resolution by increasing the refractive indices of immersion liquids. As for submicrometre-scale or nanoscale objects, standard geometrical optics fails for visible light because the interactions of such objects with light waves are described inevitably by near-field optics6. Here we report near-field high resolution by nanoscale spherical lenses that are self-assembled by bottom-up integration7 of organic molecules. These nanolenses, in contrast to geometrical optics lenses, exhibit curvilinear trajectories of light, resulting in remarkably short near-field focal lengths. This in turn results in near-field magnification that is able to resolve features beyond the diffraction limit. Such spherical nanolenses provide new pathways for lens-based near-field focusing and high-resolution optical imaging at very low intensities, which are useful for bio-imaging, near-field lithography, optical memory storage, light harvesting, spectral signal enhancing, and optical nano-sensing.

Design of an optical see-through head-mounted display with a low f-number and large field of view using a freeform prism

Abstract: It has been a challenge to design an optical see-through head-mounted display (OST-HMD) that has a wide field of view (FOV) and low f-number (f/#) while maintaining a compact, lightweight, and nonintrusive form factor. In this paper, we present an OST-HMD design using a wedge-shaped freeform prism cemented with a freeform lens. The prism, consisting of three freeform surfaces (FFSs), serves as the near-eye viewing optics that magnifies the image displayed through a microdisplay, and the freeform lens is an auxiliary element attached to the prism in order to maintain a nondistorted see-through view of a real-world scene. Both the freeform prism and the lens utilize plastic materials to achieve light weight. The overall dimension of the optical system per eye is no larger than 25 mm by 22 mm by 12 mm, and the weight is 8 g. Based on a 0.61 in. microdisplay, our system demonstrates a diagonal FOV of 53.5° and an f/# of 1.875, with an 8 mm exit pupil diameter and an 18.25 mm eye relief.

Zoom lens system, imaging device and camera

Abstract: A zoom lens system comprising a first lens unit having negative power, a second lens unit having positive power and a third lens unit having positive power, wherein in zooming from a wide-angle limit to a telephoto limit, the lens units move respectively along an optical axis in such a manner that an interval between the first lens unit and the second lens unit decreases while an interval between the second lens unit and the third lens unit changes so that variable magnification is achieved, the first lens unit comprises one object side negative lens element and one image side positive lens element with a convex surface facing the object side, which have an aspheric surface, and the conditions: n12>1.88 and ν12<26 (n12 and ν12 are refractive index and Abbe number, respectively, of the image side positive lens element of the first lens unit) are satisfied.

The sloan lens acs survey. ix. colors, lensing, and stellar masses of early-type galaxies

Abstract: We present the current photometric data set for the Sloan Lens ACS (SLACS) Survey, including Hubble Space Telescope (HST) photometry from Advanced Camera for Surveys, WFPC2, and NICMOS. These data have enabled the confirmation of an additional 15 grade "A" (certain) lens systems, bringing the number of SLACS grade "A" lenses to 85; including 13 grade "B" (likely) systems, SLACS has identified nearly 100 lenses and lens candidates. Approximately 80% of the grade "A" systems have elliptical morphologies while similar to 10% show spiral structure; the remaining lenses have lenticular morphologies. Spectroscopic redshifts for the lens and source are available for every system, making SLACS the largest homogeneous data set of galaxy-scale lenses to date. We have created lens models using singular isothermal ellipsoid mass distributions for the 11 new systems that are dominated by a single mass component and where the multiple images are detected with sufficient signal to noise; these models give a high precision measurement of the mass within the Einstein radius of each lens. We have developed a novel Bayesian stellar population analysis code to determine robust stellar masses with accurate error estimates. We apply this code to deep, high-resolution HST imaging and determine stellar masses with typical statistical errors of 0.1 dex; we find that these stellar masses are unbiased compared to estimates obtained using SDSS photometry, provided that informative priors are used. The stellar masses range from 10(10.5) to 10(11.8)M(circle dot) and the typical stellar mass fraction within the Einstein radius is 0.4, assuming a Chabrier initial mass function. The ensemble properties of the SLACS lens galaxies, e. g., stellar masses and projected ellipticities, appear to be indistinguishable from other SDSS galaxies with similar stellar velocity dispersions. This further supports that SLACS lenses are representative of the overall population of massive early-type galaxies with M* greater than or similar to 10(11) M(circle dot) , and are therefore an ideal data set to investigate the kpc-scale distribution of luminous and dark matter in galaxies out to z similar to 0.5.

Demonstration of 12 nm resolution Fresnel zone plate lens based soft x-ray microscopy

Abstract: To extend soft x-ray microscopy to a resolution of order 10 nm or better, we developed a new nanofabrication process for Fresnel zone plate lenses. The new process, based on the double patterning technique, has enabled us to fabricate high quality gold zone plates with 12 nm outer zones. Testing of the zone plate with the full-field transmission x-ray microscope, XM-1, in Berkeley, showed that the lens clearly resolved 12 nm lines and spaces. This result represents a significant step towards 10 nm resolution and beyond.

Experimental and theoretical evidence for subwavelength imaging in phononic crystals.

Abstract: We show experimentally and theoretically that super resolution can be achieved while imaging with a flat lens consisting of a phononic crystal exhibiting negative refraction. This phenomenon is related to the coupling between the incident evanescent waves and a bound slab mode of the phononic crystal lens, leading to amplification of evanescent waves by the slab mode. Super resolution is only observed when the source is located very near to the lens, and is very sensitive to the location of the source parallel to the lens surface as well as to site disorder in the phononic crystal lattice.

Advanced electro-active optic device

Abstract: Optical devices having a dynamic aperture and/or an apodization mask are provided. The aperture and/or mask may be provided by one or more electro-active elements, and may be used in an ophthalmic device that that is spaced apart from but in optical communication with an intraocular lens, a corneal inlay, a corneal onlay, or a spectacle lens that provide an optical power.

Bayesian strong gravitational-lens modelling on adaptive grids: objective detection of mass substructure in Galaxies

Abstract: We introduce a new adaptive and fully Bayesian grid-based method to model strong gravitational lenses with extended images. The primary goal of this method is to quantify the level of luminous and dark mass substructure in massive galaxies, through their effect on highly magnified arcs and Einstein rings. The method is adaptive on the source plane, where a Delaunay tessellation is defined according to the lens mapping of a regular grid on to the source plane. The Bayesian penalty function allows us to recover the best non-linear potential-model parameters and/or a grid-based potential correction and to objectively quantify the level of regularization for both the source and potential. In addition, we implement a Nested-Sampling technique to quantify the errors on all non-linear mass model parameters - marginalized over all source and regularization parameters - and allow an objective ranking of different potential models in terms of the marginalized evidence. In particular, we are interested in comparing very smooth lens mass models with ones that contain mass substructures. The algorithm has been tested on a range of simulated data sets, created from a model of a realistic lens system. One of the lens systems is characterized by a smooth potential with a power-law density profile, 12 include a Navarro, Frenk and White (NFW) dark matter substructure of different masses and at different positions and one contains two NFW dark substructures with the same mass but with different positions. Reconstruction of the source and lens potential for all of these systems shows the method is able, in a realistic scenario, to identify perturbations with masses similar to 10(7)M(circle dot) when located on the Einstein ring. For positions both inside and outside of the ring, masses of at least 10(9)M(circle dot) are required (i.e. roughly the Einstein ring of the perturber needs to overlap with that of the main lens). Our method provides a fully novel and objective test of mass substructure in massive galaxies.

Image pickup lens, image pickup apparatus, and mobile terminal

Abstract: Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected. The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side. The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis.

Stereoscopic image display apparatus

Abstract: It is made possible to provide a stereoscopic image display apparatus capable of preventing the stereoscopic display characteristics from being degraded even if the locus of light rays between the lens and the two-dimensional display device becomes long. A stereoscopic image display apparatus includes: a plane display device having a display face formed of a plurality of pixels arranged in a matrix form; an optical plate comprising a plurality of lenses which are arranged in front of the display face of the plane display device and which have a uniaxial double refractive material inserted therein, and controlling light rays from the pixels; and a sheet polarizer provided between the plane display device and the optical plate to align a polarization direction of light ray. In the double refractive material, a maximum primary axis of refractive index is parallel to ridgelines of the lenses and is inclined in a direction opposed to a viewer.

Real-time intraoperative fluorescence imaging system using light-absorption correction

Abstract: We present a novel fluorescence imaging system developed for real-time interventional imaging applications. The system implements a correction scheme that improves the accuracy of epi-illumination fluorescence images for light intensity variation in tissues. The implementation is based on the use of three cameras operating in parallel, utilizing a common lens, which allows for the concurrent collection of color, fluorescence, and light attenuation images at the excitation wavelength from the same field of view. The correction is based on a ratio approach of fluorescence over light attenuation images. Color images and video is used for surgical guidance and for registration with the corrected fluorescence images. We showcase the performance metrics of this system on phantoms and animals, and discuss the advantages over conventional epi-illumination systems developed for real-time applications and the limits of validity of corrected epi-illumination fluorescence imaging.

High-resolution, wide-field object reconstruction with synthetic aperture Fourier holographic optical microscopy

Abstract: We utilize synthetic-aperture Fourier holographic microscopy to resolve micrometer-scale microstructure over millimeter-scale fields of view. Multiple holograms are recorded, each registering a different, limited region of the sample object's Fourier spectrum. They are "stitched together" to generate the synthetic aperture. A low-numerical-aperture (NA) objective lens provides the wide field of view, and the additional advantages of a long working distance, no immersion fluids, and an inexpensive, simple optical system. Following the first theoretical treatment of the technique, we present images of a microchip target derived from an annular synthetic aperture (NA = 0.61) whose area is 15 times that due to a single hologram (NA = 0.13); they exhibit a corresponding qualitative improvement. We demonstrate that a high-quality reconstruction may be obtained from a limited sub-region of Fourier space, if the object's structural information is concentrated there.

Imaging lens, imaging device and portable terminal

Abstract: Provided is a small-sized five-element image pickup lens which ensures a sufficient lens speed of about F2 and exhibits various aberrations being excellently corrected The image pickup lens is composed of, in order from the object side, a first lens with a positive refractive power, including a convex surface facing the object side; a second lens with a negative refractive power, including a concave surface facing the image side; a third lens with a positive or negative refractive power; a fourth lens with a positive refractive power, including a convex surface facing the image side; and a fifth lens with a negative refractive power, including a concave surface facing the image side The image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with the optical axis

Freeform surface lens for LED uniform illumination.

Abstract: A method using a freeform surface lens for LED secondary optic design is proposed in this paper. By Snell's Law, the differential equations are given to build the relationship between the normal direction of a freeform surface and its input/output ray vectors. Runge-Kutta formulas are used to calculate the differential equations to design the freeform surface. Moreover, the optical model for uniform illumination is simulated and optical performance is analyzed. A practical freeform surface lens for LED uniform illumination is fabricated using an injection molding method. By the process, our system demonstrates a uniform illumination with a divergence half-angle of 6° and an efficiency of 78.6%.

Zoom lens and imaging apparatus having the same

Abstract: PROBLEM TO BE SOLVED: To provide a zoom lens 50 suppressing a flare ghost even if a pair of facing internal walls of a casing are arranged close to an optical axis for high magnification. SOLUTION: The zoom lens includes a lens-barrel 50k; a first lens group LG1 fixed to one end side of the lens-barrel 50k; and a second lens group LG2 for variable power moving on an optical axis CL of the first lens group LG1 away from and close to the first lens group LG1. A first recess 11 and a second recess 12 made in a direction away from the optical axis CL are provided near the first lens group LG1 in the internal walls 50f, 50g of the lens-barrel 50k, in this order from the first lens group LG1 side, and a relationship between the depth t1 of the first recess 11, the depth t2 of the second recess 12 and the thickness t of the internal walls is t1>t>t2. COPYRIGHT: (C)2009,JPO&INPIT

Multiscale lens design

Abstract: While lenses of aperture less than 1000lambda frequently form images with pixel counts approaching the space-bandwidth limit, only heroic designs approach the theoretical information capacity at larger scales. We propose to use the field processing capabilities of small-scale secondary lens arrays to correct aberrations due to larger scale objective lenses, with an ultimate goal of achieving diffraction-limited imaging for apertures greater than 10,000lambda .We present an example optical design using an 8 mm entrance pupil capable of resolving 20 megapixels.

Millimeter-wave quasi light integration dielectric lens antenna and array thereof

Abstract: The utility model relates to the technical field of radars, in particular to a millimeter wave quasi-optical integrated dielectric lens antenna and an array thereof. The millimeter wave quasi-optical integrated dielectric lens antenna comprises a micro-strip integrated antenna, a dielectric lens, an objective lens, an array base, a reflecting mirror, a shield and a wave beam switcher; one end surface of the dielectric lens is in the shape a hemisphere or an ellipsoid, and the other end surface thereof adopts a cylindrical section; the micro-strip integrated antenna is generated by the dielectric substrates; the front side which is tightly stuck on the cylindrical section of the dielectric lens serves as a feed source; the back side is grounded; the semi-sphere or ellipsoid end surface of the dielectric lens servrs as an antenna radiating surface; the length of the cylindrical part of the dielectric lens can be changed; the antenna array is designed as a line array or a surface array; the array base and the reflecting mirror adopt cone-shaped quasi-optical reflecting mirror surfaces; the focal point of the objective lens of the line array or the surface array is aligned with the center line of the dielectric lens; the shield is arranged outside; and the antenna array is controlled by the wave beam switcher. The antenna structure has the advantages of strong anti-shake property and dustproof property, and is suitable for receiving/transmitting sense of radars and telecommunication devices of millimeter wave airplanes, automobiles and ships.

Dielectric antenna with an electromagnetic feed element and with an ellipsoidal lens made of a dielectric material

Abstract: A dielectric antenna with an electromagnetic feed element ( 2 ) and with a lens ( 3 ) made of a dielectric material, the feed element ( 2 ) emitting electromagnetic radiation ( 4 ) and the lens ( 3 ) being supplied with electromagnetic radiation ( 4 ) in the feed region ( 5 ), the lens ( 3 ) relaying the electromagnetic radiation ( 4 ) and radiating it with the transmission region ( 6 ). To configure these dielectric antennas such that the disadvantages of the dielectric antennas known from the prior art are at least partially avoided, first of all, the lens ( 3 ) is shaped essentially ellipsoidally at least in the transmission region ( 6 ) and the lens ( 3 ) is arranged relative to the feed element ( 2 ) such that the electromagnetic radiation ( 4 ) emitted by the lens ( 3 ) in the direction of maximum radiation ( 7 ) of the antenna has an essentially planar phase front.

Orientable lens for a led fixture

Abstract: A mounting surface for mounting a plurality of LEDs has a plurality of orientable lenses each individually affixed about a single LED. Each orientable lens has a primary reflector and a refracting lens that direct light emitted from a single LED to a reflective surface of the orientable lens that reflects the light off a primary LED light output axis.

Comparative analysis of different secondary optical elements for aspheric primary lenses.

Abstract: The performance of different reflexive and refractive secondaries optimized for the same primary lens is studied by using ray-tracing simulation. Different solutions are approached according to materials and manufacturing processes currently available in the market, which can be potentially cost-effective for concentrator photovoltaic (CPV) modules. They are compared in terms of system optical efficiency and acceptance angle. In addition, irradiance distribution over the cell is also studied.

Flat panel lens

Abstract: A flat panel lens system as a tapered light guide that has minimal or no margin for fan out. The tapered light guide includes a thin end, and a thick end of which is a bevelled mirror or an optical equivalent. Light is injected into the thin end and the mirror is such that rays injected through a point at the thin end emerge collimated from one of the light guide surfaces, and that collimated rays injected at an appropriate angle through one of the light guide surfaces emerge from a point at the thin end. Bragg gratings can be utilized for color implementations as well. The tapered light guide can be fabricated as a single piece, by extrusion, injection molding, or the combination/variation of extrusion and injection molding, as well as other commonly known techniques.

Analytic models of plausible gravitational lens potentials

Abstract: Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses.

Ophthalmic device with embedded microcontroller

Abstract: This invention discloses methods and apparatus for providing an ophthalmic lens (200) with a microcontroller (204) and an energy source (208) incorporated within the ophthalmic lens. The energy source is capable of powering the micro-controller included within the ophthalmic lens. In some embodiments, an ophthalmic lens is cast molded from a silicone hydrogel.

Optical lens compression via transformation optics

Abstract: Transformation optics is widely associated with the design of unconventional electromagnetic devices, such as electromagnetic cloaks or concentrators. However, a wide range of conventional optical devices with potentially advantageous properties can be designed by the transformation optical approach. For example, a coordinate transformation can be introduced that compresses a region of space, resulting in an overall decrease in the thickness of an optical instrument such as a lens. The optical properties of a transformed lens, such as Fresnel reflection or aberration profile, are equivalent to those of the original lens, while the transformed lens and the bounding transformation optical material are thinner than the original lens. This approach to flattening the profile of a lens represents an advantage over the use of a higher dielectric material because it does not introduce greater Fresnel reflections or require a redesign of the basic optic. Though transformation optical media are generally anisotropic, with both electric and magnetic response, it is possible to arrive at a dielectric-only transformation optical distribution for a lens interacting with transverse-magnetic (TM) polarized light. The dielectric-only distribution can be implemented using broad-band, low-loss metamaterials. Lens designs for both a full transformation and a dielectric-only implementation are discussed and confirmed via finite-element simulations.

Method for adjusting position of image sensor, method and apparatus for manufacturing a camera module, and camera module

Abstract: A lens unit (15) and a sensor unit (16) are held by a lens holding mechanism (44) and a sensor shift mechanism (45). As the sensor unit (16) is moved in a Z axis direction on a second slide stage (76), a chart image is captured with an image sensor (12) through a taking lens (6) so as to obtain in-focus coordinate values in at least five imaging positions on an imaging surface (12a). An approximate imaging plane is calculated from the relative position of plural evaluation points which are defined by transforming the in-focus coordinate value of each imaging position in a three dimensional coordinate system. The second slide stage (76) and a biaxial rotation stage (74) adjust the position and tilt of the sensor unit (16) so that the imaging surface (12a) overlaps with the approximate imaging plane.

Imaging optical lens assembly

Abstract: The present invention provides an imaging optical lens assembly including, in order from the object side to the image side: a first lens group comprising a first lens element with positive refractive power, no lens element with refractive power being disposed between the first lens element and an imaged object, the first lens element being the only lens element with refractive power in the first lens group; and a second lens group comprising, in order from the object side to the image side: a second lens element with negative refractive power; a third lens element; and a fourth lens element; wherein focusing adjustment is performed by moving the first lens element along an optical axis, such that as a distance between the imaged object and the imaging optical lens assembly changes from far to near, a distance between the first lens element and an image plane changes from near to far; and wherein the number of the lens elements with refractive power in the imaging optical lens assembly is N, and it satisfies the relation: 4≦N≦5. The abovementioned arrangement of optical elements and focusing adjustment method enable the imaging optical lens assembly to obtain good image quality and consume less power.