1176 results about "Fresnel lens" patented technology

Light emitting diode systems disclosed include semiconductor diodes arranged in cooperation with electrical contacts, mounting provisions, and optical couplings; where the optical couplings include at least a Fresnel lens. A Fresnel lens is further coupled to additional optical elements such as a concave or ‘negative’ lens and still further to a reflector operating via principles of total internal reflection. Both the concave lens and the reflector are aspherical in preferred versions. A cover element of single piece plastic may be formed in a molding process whereby all three of these optical elements, i.e. the Fresnel lens, the negative lens and the reflector, are formed into the single plastic piece. Further, the plastic piece may be arranged to also accommodate auxiliary systems such as alignment indexing and fastening means as well as interlocking peripheral configurations.

A head up display system for a vehicle that includes a compact image source for projecting an image. The compact image source may be foldable up toward or into a cockpit ceiling of the vehicle, be positioned within a dashboard of the vehicle, or located at another suitable position. A combiner reflects the projected image with optical power toward an observer for observation. The combiner is positioned so that the observer, in a line of sight, may see a visual exterior view of an outside scene through the combiner and the projected image in the combiner. In a preferred embodiment, the image source includes an illumination system that includes a high power light emitting diode (LED) array assembly. A Fresnel lens array is operatively associated with the LED array assembly for receiving light produced by the LED and providing a nearly collimated light output. A spatial light modulator receives the nearly collimated light output. The preferred combiner is a meniscus combiner that includes a meniscus lens; a multi-layer dichroic coating formed on a first surface of the meniscus lens; and, an anti-reflection coating formed on a second, opposite surface of the meniscus lens. The meniscus combiner preferably utilizes a non-symmetric aspheric meniscus lens.

A planar light source, Fresnel lens sheet, and louver are disposed in the stated order in a light source apparatus. The Fresnel lens sheet deflects and focuses in one dimension light that has entered from the planar light source. The louver is disposed in the optical path of the light emitted from the Fresnel lens sheet, and the directivity of the light can be increased by restricting the traveling direction of the light to the focal direction of the Fresnel lens sheet. The light utilization ratio can thereby be increased, the directivity of planarly emitted light can be increased, and the brightness can be made uniform at the point of observation.

This specification discloses an illuminating apparatus having a light source and an optical unit disposed forwardly on the object side of the light source, the optical unit being provided with an incidence surface on which light from the light source is incident, a light emergence surface provided with a Fresnel lens, and a side reflecting surface for totally reflecting the light incident on the incidence surface toward the Fresnel lens, wherein the light totally reflected by the side reflecting surface is refracted by the Fresnel lens and efficiently irradiates the object.

A light source includes a housing, an LED array of individual LED elements mounted in the housing, and a controller mounted in the housing and coupled to the LED array. The controller sequentially, intermittently pulses the LED elements of the LED array. The controller over drives the LED elements of the LED array with a current in excess of several times the continuous forward rating for the individual LED elements. The housing is a substantially closed, waterproof, tubular member and may include a power source in the housing. The light source may form a portable light source. The light source may include a fiber optic bundle coupling in the housing and a fresnel lens between the LED array and the fiber optic bundle coupling.

A Concentrating Photovoltaics (CPV) module includes a metal frame, a plurality of Fresnel lenses, a secondary reflective or refractive concentrator, multi-junction solar cells with up to 40% efficiency and a novel heat spreading material. The Fresnel lenses and the secondary concentrator focus the sun over 500 times to maximize the amount of photons collected by the solar cells and converted to electricity. A newly designed soft board material provides coefficient of thermal expansion (CTE) matched carrier for the solar cells and an efficient electrical connectivity method. The carrier board is attached to a specially formulated heat spreader made of graphite. At 40% the weight of aluminum and 18% the weight of copper, this specially formulated material offers thermal heat conductivity that is superior to copper. The combination of the above creates CPV modules with the highest efficiency and lowest cost per Watt.

A liquid crystal diffraction lens element and an optical head device, which can switch focal lengths of both of outgoing light and returning light by a single element, are provided.

The liquid crystal lens element comprises transparent substrates 1a, 1b, a liquid crystal 4 sandwiched between the transparent substrates 1a, 1b, transparent electrodes 2a, 2b, birefringent Fresnel lens members 3a, 3b each having a Fresnel lens shape and made of a birefringent material, and a seal 5, wherein the extraordinary refractive index direction A of the birefringent Fresnel lens member 3a and the extraordinary refractive index direction B of the birefringent Fresnel lens member 3b are perpendicular to each other, and the alignment direction of the liquid crystal 4 at the interface between the liquid crystal 4 and the transparent substrate 1a is perpendicular to the alignment direction of the liquid crystal 4 at the interface between the liquid crystal 4 and the transparent substrate 1b.

A linear illumination unit (30) has a line of unlensed LEDs (31) which emit light spreading out. The light is focused into a line by a Fresnel lens (33) which allows spread and mixing of light in the linear direction and limits spread in the ortliogonal direction. A Fresnel lens is particularly effective for this purpose. The housings 34 have slots 36 to help control light spread, and the housings are open-ended to allow spread of light in the linear direction beyond the confines of the, geometry of the units. Thus, units (30) may be interconnected to provide seamless linear light in a modular manner.

An ultraviolet sterilizer for use during surgery is mounted in a base cabinet. The UV light source can be a laser, or an LED. An optical frequency multiplier can be used that outputs UV of less than 280 nm, or greater than 320 nm, to avoid burning the patient. A visible LED aiming light directs the UV light toward the surgery. A crosshair image can be projected to position the light.

One lamp has a housing, a cavity, a handle, and an ocular plate to pass the UV and the aiming light. An articulated arm allows selective positioning of the lamp. Another lamp has a stylus, a handle, and a tip small enough for easy insertion into a small incision for arthroscopy. A fiber optic cable connects the UV and the aiming light to the lamp. Lenses or filters can be used with the fiber optic cable.

An electronic power supply and a CPU connect to the UV and the aiming light sources. A keyboard inputs commands to the CPU. A sensor provides feedback.

Another UV sterilizer is mounted on a ceiling of the operating room. A lamp has a housing with a cavity. Either a curved or a flat substrate is mounted in the cavity. Solid state UV elements are arrayed on the substrate, along with visible LEDs for aiming. Either a curved or a flat mirror is disposed behind the substrate. An ocular plate passes the UV and the aiming light, and protects the elements from damage. The ocular plate is a diffuser, a filter, or a fresnel lens.

Using inhomogeneous sized liquid crystal (LC) droplets for lens and prisms. For forming a positive lens, the LC droplet size can gradually increase from the center to the side edges. For forming a negative lens, the LC droplet size can gradually decrease from the center to the side edges. The lens can be created by Ultra Violet light exposure to patterns. The lens can be tuned by applying voltage to the droplets. The inhomogeneous droplets can also be used in Fresnel lens and prisms. Applications of the invention can be used for eyeglasses, arrays, camera type zoom lenses and beam steering applications.

A reflective illumination device is disclosed, which is comprised of a light-guiding screen with light reflecting ability and at least a directional light source; wherein the light-guiding screen includes a reflecting surface having a semi-Fresnel lens structure arranged thereon. The semi-Fresnel lens structure, being designed basing on the principle of Fresnel lens, is the equivalent of a parabolic mirror that has spiral cut ridges for focusing light to a focal point, whereas the profile of the ridges can be a planar surface, a curved surface or the combination thereof. By arranging the reflecting surface with semi-Fresnel lens structure at the bottom of the light-guiding screen and each light source at a circumferential side wall of the light-guiding screen, the light beams emitting from each light source can be reflected out of the light-guiding screen by a specific angle as the direction of the light beams is adjusted to pour on the semi-Fresnel lens structure by a specific angle matching the configuration of the same.

A novel, high-efficiency, extremely light-weight, inflatable refractive solar concentrator for space power is described. It consists of a flexible Fresnel lens, flexible sides, and a back surface, together enclosing a volume of space which can be filled with low pressure gas to deploy the concentrator on orbit. The back surface supports the energy receiver/converter located in the focal region of the Fresnel lens. The back surface can also serve as the waste heat radiator. Prior to deployment, the deflated flexible lens and sides are folded against the back surface to form a flat, low-volume package for efficient launch into space. The inflatable concentrator can be configured to provide either a line focus or a point focus of sunlight. The new inflatable concentrator approach will provide significant advantages over the prior art in two different space power areas: photovoltaic concentrator arrays and high-temperature solar thermal conversion systems. Photovoltaic concentrator arrays using the new inflatable lens will be much lighter than prior space concentrator arrays. In addition, for photovoltaic concentrator arrays, the new inflatable lens will eliminate the need for a fragile glass superstrate to support the lens, substantially improving robustness of the lens. Solar thermal concentrator arrays using the new inflatable lens will be much lighter than prior art space concentrators which used parabolic mirrors. In addition, for solar thermal applications in space, the new inflatable lens will eliminate the need for high surface accuracy, which has been a significant problem for prior art concentrators.

The present invention provides an imaging lens device, which has a widely extended focusing range and exhibits good resolution over the entire focusing range. The imaging lens device comprises a liquid crystal lens for focusing an object at a prescribed distance, comprising a liquid crystal layer, a first transparent substrate disposed adjacent to one surface of the liquid crystal layer and having a first electrode and having Fresnel lens surface formed on the boundary with the liquid crystal layer, a second transparent substrate disposed adjacent to the other surface of the liquid crystal layer and having a second electrode; a controller for changing the refractive index of the liquid crystal layer for extraordinary ray by changing electric voltage applied between the first electrode and the second electrode; and an imaging element for taking an image of the object. The liquid crystal lens functions as a diffractive optical element for an extraordinary ray when the liquid crystal layer has a prescribed refractive index for an extraordinary ray incident upon the liquid crystal layer.

A high power LED lamp and method for retrofitting conventional traffic signal lamps. The LED lamp includes a housing, a power supply disposed in the housing, a plurality of LEDs mounted to a substantially planar mounting surface in the housing and electrically connected to the power supply for producing diverging light, and a threaded electrical connector extending from the housing. The method includes replacing a conventional incandescent light bulb with the LED lamp, and installing a Fresnel lens inside the traffic signal lamp that collimates and just fills and illuminates the outer lens of the traffic signal lamp.

A lighting device having a plurality of high flux LEDs mounted on a heat sink and surrounded by a diffuser and a power supply that provides independent power to individual sets of the LEDs. The heat sink serves to transfer heat from the LEDs to the outside environment. In one embodiment the lighting device is positioned within a fresnel lens to produce a distribution of light.

Head-mounted displays (100) are disclosed which include a frame (107), an image display system (110) supported by the frame (107), and a Fresnel lens system (115) supported by the frame (107). The HMD (100) can employ a reflective optical surface, e.g., a free-space, ultra-wide angle, reflective optical surface (a FS/UWA/RO surface) (120), supported by the frame (107), with the Fresnel lens system (115) being located between the image display system (110) and the reflective optical surface (120). The Fresnel lens system (115) can include at least one curved Fresnel lens element (820). Fresnel lens elements (30) for use in HMDs are also disclosed which have facets (31) separated by edges (32) which lie along radial lines (33) which during use of the HMD pass through a center of rotation (34) of a nominal user's eye (35) or through the center of the eye's lens (36) or are normal to the surface of the eye's cornea.

An illumination system for use in illuminating a spatial light modulator for a head up display system. The illumination system includes a high power light emitting diode (LED) array assembly; and, a Fresnel lens array operatively associated with the LED array assembly for receiving light produced by the LED and providing a nearly collimated light output for use by the spatial light modulator. Utilization of the ultra bright LED array and Fresnel lens array provides the capability of the illumination source to be made very thin, light weight, and efficient. The Fresnel lens array, which converges the light to be nearly collimated, enhances the harvest of the available flux thus increasing the system efficiency and providing a system that gives the illusion of having an image at infinity. Additional components such as holographic elements, optical compensation films, and brightness enhancement films can be used to tailor the light if required.

The invention discloses an automatic detecting system and method of flat base plate, which contains an optical module. The optical module has illuminating module and lens array leading beam to part of base plate. Lens array contains a Fresnel lens and optical module contains a camera. The camera has time delay integral (TDI) sensor, which receives reflected light producing by illuminating source and base plate. Telecentric imaging lens leads reflected light from base plate to camera. Illuminating module has a controller connected with a source containing multi-group LED (each LED can radiate light with different wavelength) and the controller control each LED independently. The invention can analyze large-scale flat base plate quickly, has high sensitivity and can provide high-resolution picture.

A light collection device assembled with a light-processing unit comprises a fresnel lens unit, an anti-reflection layer and a light-processing unit. The fresnel lens unit has a light-incident surface and a light-emitting surface. The light-processing unit is positioned with the light-emitting surface for transmitting or converting a light emitted from the fresnel lens unit. The anti-reflection layer is mounted or formed on the light-incident surface of the fresnel lens unit.

This invention increases the longevity and performance of solar concentrators, optical switches; and reflection, illumination, and projection equipment in general. To achieve long lifetimes this equipment is sealed to prevent egress of internal lubricant or ingress of undesirable fluids. The rotational elements are sealed to increase their abrasion resistance. Many plastic materials if not sealed as taught in the instant invention are vulnerable to UV degradation, static dust attraction, poor weatherability, and ineffective abrasion resistance resulting in damage in the field and during cleaning. This invention improves the above optical equipment by sealing them with a tough, thin, transparent film. Even in equipment with no internal lubricant, tailored sealants as described in the instant invention can improve the performance of the mirrored elements, Fresnel lenses, and parabolic reflectors. For all the devices, the sealant of the instant invention hardens the surface to prevent scratching, and furthermore can be tailored to be an anti-fogant to keep water vapor off.

A forehead thermometer includes: a main body having a probe formed on a front portion of the main body, a thermal-mass sleeve concentrically formed in a central hole of the probe, a Fresnel lens formed on a front end portion of the probe for focusing an incoming infrared temperature signal as emitted from the temperature sensing area on a patient's forehead to an infrared sensor secured to a bottom portion of the sleeve, an electronic circuit connected with the sensor and secured in the main body, and a lamp connected to the circuit and formed in the main body juxtapositioned to the sensor for projecting light forwardly to be parallel to a longitudinal axis of the Fresnel lens and the sensor for optically aiming a reference target area approximating the temperature sensing area for quickly locating the temperature sensing area for hygienically measuring a patient's body temperature.

A liquid crystal lens element is provided, which can realize a small sized element having no moving part, and which has a lens function of switching the focal length among multiple focal lengths of at least 3 types according to an applied voltage.

A liquid crystal lens element 10 is provided, which comprises a pair of transparent substrates 11 and 12 and a liquid crystal layer sandwiched between these substrates, wherein focal lengths of light transmitted through the liquid crystal 16 is changed depending on a voltage applied to the liquid crystal 16, the liquid crystal lens element 10 has a Fresnel lens-shaped concave-convex portion 17 and a liquid crystal layer 16A, and configured so that the refractive index n of the liquid crystal layer 16A changes from a refractive index n₁ at a time of no application to a refractive index n₂ at a time of voltage application, a refractive index n_s of the concave-convex portion 17 is a value between the refractive indexes n₁ and n₂ and satisfies a predetermined relation, and the maximum depth d of the concave-convex portion 17 satisfies a predetermined relation, the focal length can be switched by switching an applied voltage to the liquid crystal layer 16A under the predetermined conditions.

There is provided an illuminating device which includes: a surface light source including a plurality of light emitting diodes disposed two-dimensionally; a light condensing means comprising a plurality of Fresnel lenses which are disposed corresponding to respective light emitting diodes, and each of which converts a light from each light emitting diode into a substantially collimated light; and a light diffusing means disposed at the stage consequent to the light condensing means, and including a plurality of Fresnel lenses which have a smaller diameter and are arranged in a higher density than the Fresnel lenses of the light condensing means. The illuminating device is adapted to emit a highly bright light with excellence in brightness uniformity, and a light source unit incorporating the illuminating device disposed behind a liquid crystal panel is suitably used in an HUD.

A mask blank inspection tool includes an AFO having a diffractive lens and a refractive lens formed on a common substrate. The diffractive lens is a Fresnel zone plate and the refractive lens is a refractive Fresnel lens. The AFO is used to image light from a defect particle on a multilayer mask blank or the surface of the multilayer mask blank to a detector.

A method and apparatus for correcting vision, including a corneal-pocket keratome device to create a corneal pocket and a lens to be inserted and retained in the corneal pocket to effect correction. The corneal-pocket keratome includes a drive unit having cutting head elements which contact the subject eye during corneal pocket formation. The cutting head elements may be removeable and may be disposable. The cutting head elements include a corneal restraint device, which may be a positioning ring to position an eyeball with the cornea protruding through the ring; a keratome blade assembly with a corneal-pocket blade; and may also include an applanation shoe surface to restrain the cornea, in addition or instead of the positioning ring. The applanation shoe may be pivotable away from the surgical area. The corneal-pocket blade may include a guide which travels with the blade. The blade assembly oscillates laterally while extending forward into the cornea to form the pocket, and the amplitude of the lateral oscillation is preferably increased as the blade goes beyond an opening incision into the cornea. Lenses for this invention preferably include a feature to impede accidental lens movement after the lens is disposed within the corneal pocket, which may be a swelling after insertion or a circumferential irregularity. Lenses may be of Fresnel or non-Fresnel type, and may employ annular changes in the index of refraction of the lens material, as well as changes in refractive shape which may be annular or not, to effect variations in focal length for relieving presbyopia, astigmatism, and combinations of those as well as myopia and hyperopia. Drive control and vacuum for the positioning ring are provided under user command by a control unit having user inputs.

A liquid crystal lens element is provided, which does not produce change of transmission wavefront regardless of polarization state of incident light when it is off-state at a time of no voltage application, and which exhibits concave lens function for extraordinarily polarized incident light when it is on-state at a time of voltage application.

In a liquid crystal lens element 10 comprising a pair of transparent substrates 11 and 12 and a liquid crystal layer 16 sandwiched between the transparent substrates, which is configured to change convergent point of light transmitted through the element according to the magnitude of voltage applied to the liquid crystal layer 16, the liquid crystal lens element 10 further comprises a Fresnel lens 17 having a concave-convex-shaped cross section formed on the transparent substrate 11, a first transparent electrode 13 formed on a flat surface of the transparent substrate 11 on which the Fresnel lens 17 is formed, and a second transparent electrode 14 formed on a flat surface of the other transparent substrate 12.

A lens member includes a central axis, a light-incident side including a Fresnel-lens surface provided with a plurality of annular prisms concentrically arranged with respect to the central axis, and a light-exit surface opposite to the light-incident side. The Fresnel-lens surface further includes an annular lens portion that is concentrically arranged with respect to the central axis and that is extended to be longer and wider than the plurality of annular prisms. Provided is an optical unit in which a light source and a lens member are combined, and parts are disposed in a space provided in an outer periphery of the annular lens portion.

The invention relates to a light-gathering wind and light complementary power station with an automatic sun tracking function and a maximum power point tracking function, which comprises a light-gathering device, a photovoltaic cell array device, a tracking driving device, a photovoltaic controller with a maximum power point tracking function, and a wind generating set, wherein the light-gathering device and the photovoltaic cell array device comprise a frame consisting of a Fresnel lens light-gathering device array and a photovoltaic cell array respectively; the tracking driving device comprises an intelligent control system for driving the light-gathering device and the photovoltaic cell array device to move in a sun-tracking manner, and a mechanical control and transmission device; the photovoltaic controller with the maximum power point tracking function consists of a voltage sampling circuit, a current sampling circuit and a microprocessor in which a multiplier and a comparator are arranged; and the wind generating set consists of a wind-driven generator and a wind turbine controller. The light-gathering wind and light complementary power station has high automation degree, light weight and high photoelectric conversion efficiency. By adopting the photovoltaic controller with the maximum power point tracking function, the investment cost of photoelectric power generation can be greatly lowered, and the power generating efficiency is greatly increased.

By using high and low refractive index materials, a planarized reflective-refractive Fresnel lens and a planarized refractive lenticular lens can be created. These flat screen components eliminate the need for an air-gap, thus reducing the screen thickness. Additionally, this allows for the screen to be manufactured on a roll-to-roll process that can significantly reduce the screen cost. By adding the capability of planarizing the elements, they can be combined in a final structure on a roll-to-roll process. Since the Fresnel lens can be combined with the lenticular lens before exposure of the black stripe region, the exposure of the black stripe region can account for any deviation from true collimation or non-normal angle of incidence of the light path in the projection system design.

A lithography apparatus having achromatic Fresnel objective (AFO) that combines a Fresnel zone plate and a refractive Fresnel lens. The zone plate provides high resolution for imaging and focusing, while the refractive lens takes advantage of the refraction index change properties of appropriate elements near absorption edges to recombine the electromagnetic radiation of different energies dispersed by the zone plate. This compound lens effectively solves the high chromatic aberration problem of zone plates. The lithography apparatus allows the use of short wavelength radiation in the 1-15 nm spectral range to print high resolution features as small as 20 nm.