Showing papers on "Angular aperture published in 2011"

Lens module with low chromatic aberration

Abstract: Provided is a lens module for imaging an object on an image plane. In the order from the object side to the image side of the lens module, the lens module includes a first lens made of glass and having positive refraction power, a second lens made of plastic and having negative refraction power, a aperture stopper, a third lens having positive refraction power, and a fourth lens having negative refraction power. The lens module satisfies the following formula: Vd 1 −Vd 2 ≧35; wherein, Vd 1 is the Abbe number of the first lens in d light and Vd 2 is the Abbe number of the second lens in the d light.

Enhancement of laser interaction with vacuum for a large angular aperture.

Abstract: We study the nonlinear interaction of laser light with vacuum for a large angular aperture at electromagnetic field strengths far below the Schwinger limit. The polarization and magnetization in vacuum irradiated by a focused laser beam clearly differ from those in matter. This is due to the dependence on the Lorentz invariant, which results in a ring-shaped radiation distribution in vacuum. The number of the radiated photons increases nonlinearly with increasing angular aperture.

Hand-held colour measurement device

Abstract: The opto-electronic measuring unit (M) has an optical arrangement for receiving light emanating from a measuring object and a sensor arrangement. The measuring unit is provided with an optical axis (A) consisting of a convex entrance lens with a relatively large diameter. A lens aperture (B) lies in the focal plane of an entrance lens (L1), where an optical diffusor (D) is arranged in a beam path in immediate proximity of the lens aperture and in the focal plane of a sensor-lens (L2). An independent claim is included for a hand-held colorimeter for measuring monitors, projectors, projection surfaces and ambient light.

Passive collimating skylight

Abstract: A passive collimating skylight system includes an energy-receiving aperture defining a first plane and an energy-delivering aperture defining a second plane that is spaced apart from and non-parallel to the first plane. An energy-directing passageway extends between the energy-receiving aperture and the energy-delivering aperture to redirect radiant energy incident on the energy-collecting aperture over a range of incidence angles to the energy-delivering aperture so that the redirected radiant energy emerges from the energy-delivering aperture over a range of emergence angles that is smaller than the range of incidence angles. The passageway is defined by a wall having a first end that defines the energy-delivering aperture and a second end that defines the energy-collecting aperture, the wall tapering inwardly and having a reflective inner surface along substantially the entire length from the first end to the second end. At least a portion of the wall of the passageway can be made of a flexible reflective film.

Imaging lens, optical apparatus and method for forming image using this imaging lens

Abstract: An imaging lens includes a first lens group having a positive refractive power, an aperture stop, and a second lens group having a positive refractive power, which are disposed in order from an object. The first lens group has a first lens component having a negative refractive power and a second lens component having a positive refractive power, which are disposed in order from the object, and conditions expressed by the expressions 0.12

Tunable optofluidic aperture configured by a liquid-core/liquid-cladding structure.

Abstract: Miniaturized and tunable optical components, such as the waveguide, lens, and prism, have been of great interest for lab-on-chip systems. This Letter reports an optofluidic aperture stop formed by the liquid-core/liquid-cladding flow. The aperture size can be tuned accordingly by adjusting the flow rates. Manipulation of the aperture size allows control of the amount of light passing through the corresponding optical system as well as the angular aperture on the image side. This optofluidic aperture enables lab-on-chip optical systems to have a greater flexibility and more functionalities.

High na optical system and device

Abstract: Embodiments described herein provide an optical system having a light source (e.g., LED) and a high numerical aperture multi-element optical stack. According to one embodiment, the optical stack can reimage an entrance aperture. The multi-element optical stack can include a number of optical elements forming a series of lenses. The series of lenses comprises, a first lens positioned to receive light emitted in a first beam angle and a second lens more distal from the LED than the first lens, the second lens defining a second lens exit aperture that has at least a minimum area necessary to conserve radiance for the emission beam angle in air. The lenses in said series of lenses are configured, in combination, to successively reduce a beam angle of light from the first beam angle to the emission beam angle.

Fixed focal length lens having image stabilization function

Abstract: A fixed focal length lens has a focal length of a whole system shorter than a back focus. The fixed focal length lens includes an aperture stop, and an image-stabilizing lens unit that moves in a direction including a component of a direction orthogonal to an optical axis to reduce an image blur. The conditions of 0.1

Complex Image Method Analysis of a Plane Wave-Excited Subwavelength Circular Aperture in a Planar Screen

Abstract: A complex image method is presented for the analysis of a subwavelength circular aperture in a perfectly conducting screen of inflnitesimal thickness illuminated by a plane wave The method is based on the Bethe-Bouwkamp quasi static model of the aperture fleld and uses the spectral domain formulation as the point of departure Closed-form expressions are obtained for the electromagnetic flelds valid for all observation points Sample numerical results demonstrate the accuracy and e-ciency of the method for both normal and oblique illuminations, including an evanescent wave In the latter case, the results show a circulating power ∞ux and enhanced fleld conflnement near the aperture

Imaging lens, optical apparatus equipped therewith, and method for manufacturing imaging lens

Abstract: The imaging lens includes, in order from an object side, a first lens group having positive refractive power; and a second lens group having the positive refractive power, the first lens group being fixed with respect to an image plane, the second lens group being moved toward the object side to adjust a focus on a close object, and a given conditional expression being satisfied, thereby disclosing a downsized imaging lens having a wide angle of view, capable of preferably correcting various aberrations upon focusing on a close object from an infinitely distant object and having high optical performance over an entire picture, an optical apparatus including the imaging lens and an imaging lens manufacturing method.

3d image sensor

Abstract: An integrated image sensor capable of determining the distance to objects contained in a scene including at least a set of first pixels and a set of second pixels, the first and second pixels being alternately distributed in an array, the first pixels having a different angular aperture than the second pixels.

Image capture lens and image capture device

Abstract: The present invention is to provide an imaging lens and an imaging device that achieve optical performance high enough for high-pixel imaging elements, and have the smallest possible sizes and thicknesses. A first lens having positive refractive power, an aperture stop, a second lens having positive or negative refractive power, a third lens having negative refractive power, a fourth lens having positive refractive power, and a fifth lens having negative refractive power are provided in this order from the object side, and the following conditional expressions (1), (2), and (3) are satisfied:(1) 0.80 < f 1 /f < 1.40, (2) f 1 /|f 3 | < 1.50, and (3) -0.20 < f 1 /f 2 < 0.90, where f represents the focal length of the entire lens system, f 1 represents the focal length of the first lens, f 2 represents the focal length of the second lens, and f 3 represents the focal length of the third lens.

Adjustable-aperture infrared cameras with feedback aperture control

Abstract: A thermal infrared camera may be used under a wide variety of target-scene radiation conditions, with interchangeable or zoom lenses requiring matching or different size cold stops. A variable aperture assembly of a thermal infrared camera integrates a rigid open truss-like framework that's capped by an aperture ring and bottomed by a driving ring, and a radiation shield, located inside the framework, that contains an aperture ring at an upper side. A plurality of blades that collectively define an aperture positioned between the upper aperture rings. Opposite blade ends are coupled to respective ones of the two aperture rings, permitting pivotal movement in one ring and radial movement in the other ring, when the rings are rotated relative to one another, to change the size of the formed aperture. Both refractive and reflective infrared telescopes may be retro-fitted with variable aperture devices to enhance infrared imaging performance.

Three-Piece Optical Pickup Lens

Abstract: A three-piece optical pickup lens includes, sequentially from an object side to an image side of the three-piece optical pickup lens along an optical axis thereof, an aperture stop, a first lens, a second lens, and a third lens. The first lens is a meniscus lens of positive refractive power. The second lens has an object side and an image side, on each of which at least one inflection point is formed at a position located between a center and a periphery of the second lens. The third lens has an object side and an image side, on each of which at least one inflection point is formed at a position located between a center and a periphery of the third lens, and has positive refractive power at paraxial region of optical axis.

Refined modeling of angular distributions of linear absorption and fluorescence in biaxial crystals

Abstract: We provide a deeply detailed description of linear absorption and fluorescence angular distributions in biaxial media; we properly take into account the distributions of the polarization eigenmode vectors around the principal plane of the dielectric frame that contains the optical singularities of the optical axes. By introducing a non-zero angular aperture of experimental detection setups and a related angular integration of absorption and fluorescence angular distributions, we provide for the first time a complete interpretation and refined modeling of former experimental measurements. Such developments should be considered to perform relevant metrology of low-symmetry biaxial materials for optics.

Angular Spacing Control for Segmented Data Pages in Angle-Multiplexed Holographic Memory

Abstract: To improve the recording density of angle-multiplexed holographic memory, it is effective to increase the numerical aperture of the lens and to shorten the wavelength of the laser source as well as to increase the multiplexing number. The angular selectivity of a hologram, which determines the multiplexing number, is dependent on the incident angle of not only the reference beam but also the signal beam to the holographic recording medium. The actual signal beam, which is a convergent or divergent beam, is regarded as the sum of plane waves that have different propagation directions, angular selectivities, and optimal angular spacings. In this paper, focusing on the differences in the optimal angular spacing, we proposed a method to control the angular spacing for each segmented data page. We investigated the angular selectivity of a hologram and crosstalk for segmented data pages using numerical simulation. The experimental results showed a practical bit-error rate on the order of 10-3.

Super wide angle lens arrangement for infrared applications

Abstract: The invention relates to high resolution, super wide angle optical assemblies for IR imaging. More particularly, a wide-angle optical assembly for an IR camera is described, comprising a lens system consisting of an object-side lens (2) and an image-side lens (3), and an aperture stop (1) on the object-side of the assembly, wherein: the object-side lens (2) and the image-side lens (3) are positive meniscus lenses; all centers of vertex radii of the lens surfaces are oriented towards the object-side, defining for each lens a concave surface and a convex surface; the thickness (8) of the object-side lens (2) is larger than 0,60 EFL; the thickness (9) of the image-side lens (3) is between 0,30 EFL and 0,70 EFL; 0.95 < BFL / EFL < 1.2; and, the EFL amounts to between 55% and 75% of the image plan diagonal. This assembly combines a wide field of view with the high spatial resolution needed to fully exploit state of the art 17 μm pixel pitch IR detectors. This is achieved using only two lenses, thus offering a cost advantage over existing many-lenses assemblies.

Apparatus for and method of imaging targets with wide angle, athermalized, achromatic, hybrid imaging lens assembly

Abstract: A wide angle, athermalized, achromatic, hybrid imaging lens assembly captures return light from a target over a field of view, and projects the captured return light onto an array of image sensors of a solid-state imager during electro-optical reading of the target. The assembly includes a plastic lens group for optical aberration compensation, a glass lens group spaced away from the plastic lens group along an optical axis, and an aperture stop between the lens groups and having an aperture through which the optical axis extends. The glass lens group has substantially all the optical power of the imaging lens assembly for thermal stability, and the plastic lens group has substantially no optical power. A holder holds the lenses and the aperture stop in front of the array.

Dome-type camera and aperture control method

Abstract: A dome-type camera includes a camera lens capable of rotating in a tilt direction, a dome cover for covering the camera lens, and an aperture control unit for controlling the amount of aperture of the camera lens. The amount of aperture is set to become smaller from an open value toward a closed value in accordance with the tilt angle of the camera lens becoming smaller from a zenith direction of the dome cover toward a horizontal direction. According to this dome-type camera, a desirable low tilt angle image with a reduced blur may be obtained even with a megapixel dome camera.

Image pickup lens, image pickup apparatus, and portable terminal device

Abstract: An image pickup lens includes a first lens having a positive meniscus shape convex toward an object side, a second lens disposed on an image side of the first lens and has a meniscus shape convex toward the image side, and an aperture stop disposed on the object side of the image side surface of the first lens, and satisfies conditional expressions given below, in which f is a focal length of the entire system, f1 is a focal length of the first lens, f2 is a focal length of the second lens, R5 is a paraxial radius of curvature of the object side surface of the second lens, and R6 is a paraxial radius of curvature of the image side surface of the second lens 100< f 1 /f <150 11< f 2 /f 1 <39 20<( R 5 +R 6 )/( R 5 −R 6 )<54

Ophthalmologic imaging device

Abstract: An ophthalmologic imaging device can shoot a diagnostically important area from the macula to the optic papilla in a wide angle of view without flares without trouble by a single imaging operation. An optical illumination system (25) includes a cornea aperture (34), an iris aperture (35), and a lens aperture (36) conjugate to the cornea (C) of the subject eye (E), the iris of the subject eye (E), and the posterior surface of the lens, respectively, and an split mark projection system (41) for focusing on the fundus (Ef) of the subject eye (E). A light source (37) is controlled by a controller to emit light for being able to obtain at least two consecutive fundus images. An inner aperture image (q3') corresponding to the lens aperture (36) is projected on the posterior surface of the lens. The controller (23) controls the lens aperture (36) so that for obtaining a second fundus image, the inner aperture image (q3') is projected at a position shifted relative to the optical axis of an optical observatory or imaging system (27, 26) from a position at which the aperture image is projected for obtaining a first fundus image.

Light-scanning systems

Abstract: Various light-scanning systems that can be used to perform rapid point-by-point illumination of a focal plane within a specimen are disclosed. The light-scanning systems can be incorporated in confocal microscopy instruments to create an excitation beam pivot axis that lies within an aperture at the back plate of an objective lens. The light-scanning systems receive a beam of excitation light from a light source and direct the excitation beam to pass through the pivot point in the aperture of the back plate of the objective lens while continuously scanning the focused excitation beam across a focal plane.

A Study on the Resonant Transmission through a Ridge-Loaded Small Circular Aperture

Abstract: In this paper, the electromagnetic wave transmission through a ridge-loaded small circular aperture is considered. The transmission problem when a plane wave is normally incident on the aperture in an infinite conducting plane is solved by a method of moments(MoM). From the results for the transmitted power and the patterns of radiation from the aperture, the transmission characteristics of a small sub-wavelength circular aperture, a ridge-loaded circular aperture, and a half wavelength slot are compared. In addition, the theoretical study is verified through the experiments for the apertures fabricated on an Flexible Printed Circuit Board(FPCB), which shows fairly good agreements with the simulated results.

Projection lens system with long back focal length

Abstract: A projection lens system, in the order from a magnified side to a reduced side, includes a first lens group with negative refraction power and a second lens group with positive refraction power. The projection lens system satisfies the formulas: −1.55

Fixed focal length lens having image stabilization function and optical apparatus

Abstract: A fixed focal length lens has a focal length of a whole system shorter than a back focus. The fixed focal length lens includes an aperture stop, and an image-stabilizing lens unit that moves in a direction including a component of a direction orthogonal to an optical axis to reduce an image blur. The conditions of 0.1

Spherical aberration of planar square aperture microlens array

Abstract: Ion thermal diffusion theory was applied to analyze the influence on numerical aperture and focal length of planar square aperture microlens array (PMLA). Moreover, numerical aperture and focal length with different ion-exchanging time but the same size of mask aperture were measured experimentally. Then, we measured the longitudinal and transverse spherical aberration by the method of parallel light incidence and emergent light pupil and improved the aberration of square-aperture PMLA by annealing treatment. Experiment results show that the spherical aberration is decreased obviously after annealing process. Meanwhile, imaging resolution is also improved more greatly. PMLA optical system with continuously adjustable focal length was proposed, which was made up of two pieces of square aperture PMLA and an aspherical lens and focal length can be adjusted continuously just by precisely adjusting the distance between the two pieces of square aperture PMLA.

Three-dimensional image sensor

Abstract: An integrated image sensor capable of determining the distance to objects contained in a scene including at least a set of first pixels and a set of second pixels, the first and second pixels being alternately distributed in an array, the first pixels having a different angular aperture than the second pixels.