Abstract: An optical receiver lens has a three-dimensional lens surface, for receiving the laser radiation of a laser distance measuring device, said laser radiation being reflected at an object, wherein the receiver lens can be described in a three-dimensional coordinate system having three axes x, y, z arranged at right angles with respect to one another and wherein the z-axis coincides with the optical axis of the receiver lens. At least one non-spherical area section of the lens surface can be described by addition of a first area, the flexure of which along the z-axis is a first function (f1) of x and y, in particular of (I) and a second area, the flexure of which along the z-axis is a second function (f2) of x and not of y. A distance measuring device is also described.

Abstract: A zoom lens system comprising a plurality of movable lens units which individually move along an optical axis at the time of zooming from a wide-angle limit to a telephoto limit during image taking, wherein at least two of the movable lens units are focusing lens units which move along the optical axis at the time of focusing from an infinity in-focus condition to a close-object in-focus condition in at least one zooming position, and among the focusing lens units, a lens unit having the absolute value, which is not the greatest absolute value, of a wobbling value at a wide-angle limit is a wobbling lens unit which senses a moving direction of the focusing lens units at the time of focusing by wobbling itself in a direction along the optical axis; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A projection lens system includes, in order from the magnified side to the reduced side thereof, a first lens group with negative refractive power, and a second lens group with a positive refracting power. The first lens group includes a first lens having a negative refracting power. The projection lens system satisfies the following condition: 4.5<|F1|/F<6; wherein F1 is the effective focal length of the first lens; F is the effective focal length of the projection lens system.

Abstract: An optical image capturing system includes, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, a fifth lens element, a sixth lens element and a seventh lens element. The first lens element with positive refractive power has a convex object-side surface. The second through fifth lens elements all have refractive power. The fifth lens element has a convex image-side surface. The sixth lens element with positive refractive power has both of the object-side and image-side surfaces thereof being aspheric. The seventh lens element with negative refractive power has a concave image-side surface and both of the object-side and image-side surfaces thereof being aspheric. The image-side surface of the seventh lens element changes from concave at a paraxial region to convex at a peripheral region.

Abstract: This invention provides an imaging lens system comprising two non-cemented lens elements with refractive power: a positive first lens element having a convex object-side surface at a paraxial region and a convex or flat image-side surface at the paraxial region; and a negative second lens element having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region, and both the object-side and image-side surfaces being aspheric; wherein, the shape of the image-side surface of the second lens element changes from concave when near an optical axis to convex when away from the optical axis. By such arrangement, the imaging lens system has not only a shorter total track length for compact electronic products, but also the advantage of a more comparable focusing performance between the short wavelength and long wavelength applications with improved image quality.

Abstract: An image pickup lens includes a first lens with positive refractive power having a convex object side surface, an aperture stop, a second lens with negative refractive power having a convex image side surface, a third lens with positive refractive power having a concave image side surface, a fourth lens with positive refractive power having a convex image side surface, and a fifth lens with negative refractive power as a double-sided aspheric lens having a concave image side surface near the optical axis; wherein the first lens and the second lens satisfy following conditional expressions (1) and (2); 50<?1<85??(1) 20<?2<35??(2) where ?1 represents an Abbe number of the first lens, and ?2 represents an Abbe number of the second lens, and where the second lens satisfies a following conditional expression (3); 1.55<Nd2<1.70??(3) where Nd2 represents a refractive index of d-ray of the second lens.

Abstract: In an embodiment, a low height imaging system has: one or more optical channels and a detector array, each of the optical channels (a) associated with at least one detector of the array, (b) having one or more optical components and a restrictive ray corrector, and (c) configured to direct steeper incident angle field rays onto the at least one detector.

Abstract: A macro lens and an imaging apparatus include, in the order from an object side to an image side, a first lens group, a second lens group, and a third lens group. Focusing is performed by fixing the first lens group and the third lens group, and by moving the second lens group having a positive refractive power as a whole on the optical axis in focusing from an infinite object to a close distance object. The first lens group has a plane S1 and a plane S2 of curvature radii of a same sign and satisfying a specified condition.

Abstract: The invention relates to an optical device produced by cutting a wafer-scale package comprising at least one optical module formed from a substrate (1) pierced with a plurality of through-holes (2) and optical elements disposed in the holes. According to the invention, at least one of the holes receives two lenses (3, 4) made from at least one polymer material transparent in the 400 nm-700 nm range, each of the lenses being defined by an external diopter and an internal diopter. The invention is characterised in that a space is formed between the internal diopters of two lenses and in that the substrate contains no polymer material between two adjacent through-holes.

Abstract: Embodiments are disclosed herein related to the construction of optical elements for an RGB camera system. One disclosed embodiment provides a wide-angle lens construction, comprising a first, negative stage, and a second, positive stage positioned behind the first, negative stage along an optical axis of the lens construction. The second, positive stage further comprises a first positive lens substage, a first negative lens substage, a second positive lens substage, and a second negative lens substage.

Abstract: This invention provides an imaging lens system comprising two non-cemented lens elements with refractive power: a positive first lens element having a convex object-side surface at a paraxial region and a convex or flat image-side surface at the paraxial region; and a negative second lens element having a concave object-side surface at a paraxial region and a concave image-side surface at a paraxial region, and both the object-side and image-side surfaces being aspheric; wherein, the shape of the image-side surface of the second lens element changes from concave when near an optical axis to convex when away from the optical axis. By such arrangement, the imaging lens system has not only a shorter total track length for compact electronic products, but also the advantage of a more comparable focusing performance between the short wavelength and long wavelength applications with improved image quality.

Abstract: Embodiments are disclosed herein related to the construction of optical elements for depth sensor systems. One disclosed embodiment provides a wide-angle lens construction comprising a first, negative stage, and a second, positive stage positioned behind the first, negative stage along an optical axis of the lens construction. The second, positive stage further comprises a first positive lens substage, a second positive lens substage, a third positive lens substage, the second positive lens substage positioned between the first positive lens substage and the third positive lens substage.

Abstract: A fish eye lens system and a photographing apparatus including the same, the fish eye lens system including, in an order from an object side to an image side: a first lens group having a negative refractive power; an aperture stop; and a second lens group having a positive refractive power, wherein the first lens group includes, in the order from the object side to the image side, a (1-A)-th lens group having a negative refractive power, a (1-B)-th lens group having a negative refractive power, and a (1-C)-th lens group including at least one positive lens, and wherein the (1-B)-th lens group is moved to perform focusing.

Abstract: The method includes: calculating positional and angular magnification distributions of rays reflected by a reference aspheric surface on a light-receiving sensor and on a sensor conjugate surface; measuring a first wavefront of a reference light on the sensor; and calculating a second wavefront of the reference light on the sensor based on a parameter of an optical system. The method includes: moving at least two movable elements for calibration such that a difference between rotationally symmetric components of the first and second wavefronts becomes small; measuring, after the calibration, a third wavefront of the reference light on the sensor; measuring, after the calibration, a fourth wavefront of the measurement light on the sensor; and calculating the profile of the measurement object aspheric surface by using the third and fourth wavefronts, the positional and angular magnification distributions, and the profile of the reference aspheric surface.

Abstract: Bezel-concealing display covers and display devices are disclosed. In one example, a bezel-concealing display cover includes a bezel and a display panel includes a perimeter portion having a first surface and a second surface such that the perimeter portion is configured to be offset from the bezel of the display device by a gap GA. The bezel-concealing display cover further includes a first array of prisms on at least one of the first surface or the second surface of the perimeter portion that extend from an edge of the perimeter portion to a distance L. Each prism of the first array of prisms has a prism angle ?, and the first array of prisms is configured to shift a portion of an image proximate the bezel produced by the display panel such that the shifted portion of the image appears over the bezel to an observer.

Abstract: An image pick-up optical lens assembly, sequentially arranged from an object side to an image side along an optical axis, comprises: a first lens element with a positive refractive power having a convex object-side surface, a second lens element with a negative refractive power, a third lens element with a positive refractive power, a meniscus fourth lens element with a positive refractive power having at least one aspherical optical surface, and a fifth lens element with a positive refractive power having at least one inflection point on the optical image-side surface. Additionally, the image pick-up optical lens assembly satisfies several particular conditions. The invention possesses features such as good aberration compensation, well-performed modulation transfer function and short total length of lens assembly applicable for compact cameras and mobile phones.

Abstract: An image pickup lens having a four lens configuration in which a bi-concave first lens, a bi-convex second lens, a bi-concave third lens, and a positive fourth lens are disposed in this order from an object side. Here, at least one of the first, second, third, and fourth lenses has an aspherical surface on each side. The image pickup lens satisfies Conditional Expression (1) given below when a refractive index of the second lens with respect to d-line is taken as Nd2. 1.

Abstract: Optical camera systems for nondestructive internal inspection of online, operating power generation turbines, including gas turbine combustor and turbine sections that are at high operating temperatures in the range of over 600° C. (1112° F.) and which include combustion gas contaminants. The inspection system includes one or more aspheric lenses capable of withstanding continuous operating temperatures above 600° C. The aspheric lenses, alone or in combination with spherical lenses, establish a wider field of view, and require fewer lenses in combination than lens mounts incorporating only spherical lenses. A cooling system incorporated in the inspection system facilitates continuous operation and inhibits lens external surface fouling from combustion gasses.

Abstract: A multi-layered lens having a substrate with opposing first and second surfaces. The substrate is formed of a plurality of discreet polymer layers. A cavity is formed into the first surface and is defined by a non-planar cavity surface that acts as a lens surface. The cavity extends into and exposes each of the plurality of polymer layers. The compositions of the polymer layers can vary to provide optimized focal properties. Alignment marks in the form of cavities or protrusions can be formed at the first surface or the second surface, so that multiple lenses can be stacked together in an aligned manner to form a stacked lens assembly.

Abstract: An optical imaging lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, and a fourth lens element with negative refractive power. The third lens element includes a convex image-side surface. The fourth lens element includes a concave image-side surface, and at least one of two surfaces of the fourth lens element is aspheric. Additionally, the optical imaging lens assembly also includes an aperture stop and an image sensor disposed at an image plane. By adjusting the relationship among the above-mentioned lens elements, the aperture stop, the image sensor and the image plane, the optical imaging lens assembly can effectively reduce the total optical length and correct the aberration as well as the chromatism to obtain superior imaging quality.

Abstract: A lens module includes a holder defining a cavity and a barrel retained within the cavity, and includes a first optical axis X aligned with an imaginary axis of the cavity, a frame defining a through hole and comprising several blocking portions, and a square lens possessing a second optical axis Y. The frame is coupled to the holder, and an imaginary axis of the through hole is aligned with the axis of the cavity. The square lens is connected to the frame and includes four side surfaces abutting the several blocking portions, which precisely aligns the second optical axis Y with the imaginary axis of the through hole.

Abstract: It has conventionally been difficult to reduce the size of a fast lens system having an F number of about 1.4 to 2.4. In a lens system of the present invention, a positive lens element is disposed closest to an object side. A diaphragm is disposed in a widest air space in the lens system. The lens system of the present invention satisfies the following conditions: 0.05<L_1/L—TH<0.21 1.5<L—TH/Y<8 where L_1 is an interval from a lens surface located closest to the object side to a lens surface located on the object side relative to the diaphragm; L_TH is an interval from the lens surface located closest to the object side to a lens surface located closest to an image side; and Y is a maximum image height.

Abstract: The present invention provides a lens having broadband anti-reflective nanostructures formed using nano-island masks and a method for making the same, in which nanostructures having a size and period equal to or smaller than the light wavelength are formed on the surface of a lens to obtain a lens having decreased reflectance, increased transmittance and high efficiency. The lens having broadband anti-reflective nanostructures formed using nano-island masks comprises: a lens having a planar shape or a predetermined curvature; and anti-reflective nanostructures formed on one surface of the lens using nano-island masks, in which the horizontal and vertical cross-sections of the anti-reflective nanostructures have a size equal to or smaller than the light wavelength.

Abstract: A single focal length lens system comprising: at least a front lens unit having positive or negative power, and being fixed in focusing; a focusing lens unit having positive power, and moving along an optical axis in focusing; and a rear lens unit having negative power, and being fixed in focusing, wherein the focusing lens unit includes: a cemented lens of a negative lens and a positive lens; and a positive single lens located on the image side relative to the cemented lens and having an aspheric surface, the rear lens unit is composed of one single lens, and the condition: ?0.5<fW/fGR<?0.1 (fW, fGR: focal lengths of the entire single focal length lens system, the rear lens unit) is satisfied.

Abstract: In order to produce, for example, an image sensing module which has a resolving power enough to meet required specifications for both photographing a close object and photograph a far object, and which has a simple structure, an image sensing module includes: an imaging lens having an increased depth of field and a decreased curvature of field; and a sensor provided between (i) a location of a best image surface of the imaging lens with respect to white light from a sunflower and (ii) a location of a best image surface of the imaging lens with respect to white light from a tree.

Abstract: A lens optical system including, in a sequence from an object to an imaging device on which an image of the object is formed; a first lens having a a positive refractive power; a second lens having negative refractive power; a third lens having a a positive refractive power; and a fourth lens having a negative refractive power and an incident surface facing the object is concave and an exit surface facing the imaging device has an inflection point.

Abstract: A single focal length lens system comprising a front lens unit, an aperture diaphragm, and a rear lens unit, wherein the front lens unit is composed of three or less lenses including a negative lens located closest to the object side and a positive lens located on the image side relative to the negative lens, and does not move along an axis in focusing, the rear lens unit includes a focusing lens unit moving along the axis and a fixed lens unit not moving along the axis in focusing, and the conditions: 0.4<fW/fGF<1.5, 0.9<fW/T1<4.5, and ?0.3<fW/fG1<0.3 (fW, fGF, fGF: focal lengths of the entire single focal length lens system, the focusing lens unit, the front lens unit, T1: an axial distance from an object side lens surface of the negative lens to the aperture diaphragm) are satisfied.

Abstract: A Fresnel lens comprises a first surface, and a second surface being the reverse side surface of the first surface and having a plurality of lens surfaces. Each lens surface is configured from a part of a side surface of an elliptical cone, which has an apex located on the second surface side and a bottom surface located on the first surface side. Here, in the Fresnel lens, any normal line intersecting with the lens surface configured from the part of the side surface of the elliptical cone among normal lines of respective points on the first surface is non-parallel to a central axis of the elliptical cone corresponding to the lens surface with which the any normal line intersects.

Abstract: An optical system, in particular a projection objective, for microlithography, has an optical axis and at least one optical correction arrangement, which has a first optical correction element and at least one second optical correction element, wherein the first correction element is provided with a first aspherical surface contour, and wherein the second correction element is provided with a second aspherical surface contour, wherein the first surface contour and the second surface contour add up at least approximately to zero, wherein the correction arrangement has at least one drive for movement of at least one of the two correction elements. In this case, at least one of the two correction elements can rotate about a rotation axis which is at least approximately parallel to the optical axis, and the at least one drive is a rotary drive for rotation of one or both of the correction elements about the rotation axis.

Abstract: Provided are a wafer scale lens, which is so short in an optical total length with respect to an image height that it can correct an aberration satisfactory, and an optical system including the wafer scale lens and having a thin lens element on the side closest to the image. The optical system includes a first lens having a positive refractive power relative to an object, and a second lens arranged on the side of the image of the first lens and having a recessed shape on the side of the object. At least one lens is arranged on the side of the second lens.

Abstract: A wide angle photographic lens assembly comprises, in order from an object side to an image side, a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface, a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface, a third lens element, a fourth lens element with positive refractive power, a fifth lens element with negative refractive power, and a sixth lens element with positive refractive power. By adjusting the conditions among the above-mentioned lens elements, the wide angle photographic lens assembly can provide a wide-field of view and correct the aberration in order to obtain superior imaging quality.

Abstract: An optical lens assembly comprises, in order from an object side to an image side, a front lens group, a stop, and a rear lens group. The front lens group comprises a first lens element with negative refractive power having a concave object-side surface. The rear lens group comprises a second lens element with positive refractive power having a concave object-side surface and a convex image-side surface, a third lens element with positive refractive power, a fourth lens element with negative refractive power having a concave object-side surface and a convex image-side surface. At least one of two surfaces of the fourth lens element is aspheric. By adjusting the curvature radii of the object-side and the image-side surfaces of the first lens element and the focal lengths of the third lens element and the optical lens assembly, the length of the optical lens assembly is reduced, the aberration is corrected.

Abstract: A wide viewing angle optical lens assembly comprises, in order from an object side to an image side, a first lens element with negative refractive power having a convex object-side surface and a concave image-side surface, a second lens element with positive refractive power having a convex object-side surface, a third lens element with positive refractive power having a convex image-side surface. By adjusting the relationship among the above-mentioned lens elements, the wide viewing angle optical lens assembly can effectively reduce its size, obtain greater angle of view as well as superior imaging quality.

Abstract: An ocular lens used in an optical apparatus, such as a telescope optical system, includes the following lens groups sequentially arranged from the object side: a first lens group G1 having negative refracting power; a second lens group G2 including a lens component having a convex surface facing the viewer's eye side; and a third lens group G3 having positive refracting power. An object-side focal plane of the third lens group G3 is located between the second lens group G2 and the third lens group G3. The first lens group G1 includes the following lens components sequentially arranged from the object side: a first lens component G1A having a convex surface facing the object side, having negative refracting power, and having a meniscus shape; and a second lens component G1B having negative refracting power.

Abstract: Imaging optics having reduced susceptibility to thermally-induced stress birefringence for imaging an object plane to an image plane; comprising an aperture stop positioned between the object plane and the image plane; a first group of optical elements located on the object plane side of the aperture stop; and a second group of optical elements located on the image plane side of the aperture stop. The optical elements in the first and second groups that are immediately adjacent to the aperture stop are refractive lens elements fabricated using optical materials having a negligible susceptibility to thermal stress birefringence, and the other optical elements are a combination of reflective optical elements and refractive lens elements fabricated using optical materials having at most a moderate susceptibility to thermal stress birefringence.

Abstract: A lens system includes a first to fifth lenses. The second and fifth lenses have negative refractive power and the others have positive refractive power. The lens system satisfies: D/TTL>1.05; Z/Y>0; G3R1/F3>G1R1/F1>0; G1R2/F1<G3R2/F3<0; and G5R1/F5<G5R2/F5<0, where D is the diameter of the optical images of the lens system, TTL is the total length of the lens system, Z is the distance between the outer periphery of an image-side surface of the fourth lens to the center of an object-side surface of the fourth lens, Y is the distance between the outer periphery of the fourth lens to the center of the fourth lens, G1R1, G2R2, G3R1, G3R2, G5R1 G5R2 are the radii of curvature of the object-side and image-side surfaces of the first, third, fifth lenses, respectively, and F1, F3, F5 are focal lengths of the first, third, fifth lenses, respectively.

Abstract: Illumination lenses having surfaces shaped according to given differential equations in order to distribute light in a highly controlled manner with minimum reflection losses are provided. These lenses also have surfaces angled and arranged in such a way that they can be molded with relatively simple molds.

Abstract: An image pick-up optical system, in order from an object side to an image side, along an optical axis comprising: the first lens element with negative refractive power having a convex object-side surface and a concave image-side surface, the second lens element with positive refractive power, a bi-convex third lens element with positive refractive power, the fourth lens element with negative refractive power having a concave object-side surface, a plastic fifth lens element with positive refractive power having a convex object-side surface and at least one aspherical optical surface. Additionally, the image pick-up optical system satisfies conditions related to shorten the total length and to enhance the ability of wider field of view for use in compact cameras and mobile phones.

Abstract: A device for acquiring equally blurred intermediate image to realize Extension of DOF imaging is characterized in that: the lens of said device produces space-invariant and approximately equal psf output in the designed range of the depth-of-field; the lens realizing space-invariant transfer characteristic is a multi-focal points lens with ray compensation; the angle of the ray guided by the multi-focal point changes in response to the object distance, but the corresponding position and energy distribution of the light spot on the image surface remain constant substantially.

Abstract: An optical image capturing lenses includes, in order from an object side to an image side, a front lens group, a stop, and a rear lens group. The front lens group includes, in order from the object side to the image side, at least a first lens element and a second lens element. The first lens element has a convex object-side surface and a concave image-side surface. The rear lens group includes, in order from the object side to the image side, at least a third lens element, a fourth lens element, a fifth lens element, and a sixth lens element. The sixth lens element is made of plastic material. The object-side surface and the image-side surface of the sixth lens are aspheric. The sixth lens element has at least one inflection point formed on at least one of the object-side surface and the image-side surface thereof.

Abstract: An photographing optical lens assembly includes, in order from an object side to an image side, a first lens element with positive refractive power having a convex object-side surface, a second lens element, a third lens element, a fourth lens element having at least one aspheric surface, a fifth lens element having a convex object-side surface and a concave image-side surface with at least one surface being aspheric and at least one inflection point being formed, and a sixth lens element having a concave image-side surface with at least one surface being aspheric. By adjusting the curvature radii of the fifth lens element, the photographing optical lens assembly can stay compact and correct the aberration while obtaining superior imaging quality.

Abstract: A projection display system and method is provided. One or more light sources, such as solid state lasers, generates light of various colors that is modulated by a spatial light modulator, such as a digital micro-mirror device. The projection optics of the system include a telecentric rear group of lenses followed by a pair of aspheric lenses formed of a continuous piece of material. A folding mirror, such as a single-piece or multi-piece angular mirror, is disposed along the optical path between the aspheric lenses, to reduce the depth of the enclosure, and an aspheric mirror projects the image onto a projection screen. A folding mirror may be used after the aspheric mirror to further reduce the depth of the enclosure.

Abstract: An optical system comprises, in order from the object side, an aperture stop, a first lens with positive refracting power, a second lens with negative refracting power, and a third lens, both surfaces of the third lens are an aspherical surface in which refracting power varies in accordance with distance from the optical axis in such a way that the both surfaces have a convex shape facing toward the object side in the vicinity of the optical axis and have a concave shape facing toward the object side in the vicinity of the outer circumference, and the following conditions (1) and (2) are satisfied: 2.2<d2/d3<7??(1) ?0.04<f/f3<0.04??(2) where d2 is the thickness of the first lens on the optical axis, d3 is a space distance between the first and second lenses on the optical axis, f is a focal length of the whole of the wide angle optical system, and f3 is a focal length of the third lens.

Abstract: An optical unit includes a plurality of lenses arranged along an optical path from an object side toward an image side, the plurality of lenses including at least one lens including an image side surface and an object side surface, one of which is formed to be an aspheric surface at wafer level, the aspheric surface of the at least one lens being formed to serve as one of an aperture stop surface having an aperture stop function and a light-shielding surface having a light-shielding function.

Abstract: An auto-focusing lens module includes an object lens, a liquid zooming unit, and an image lens group. The object lens and the liquid zooming unit receive an object image in front and condense the image into a first-stage output light. A zoom quantity is determined by an external control on the liquid zooming unit. The image lens group including a first and second lens receives the first-stage output light to transmit a second-stage output light. The first lens has a first and second surface, in which the second surface is farther than the first surface to the liquid zooming unit and has a convex curving surface protruding toward an image sensor. The second lens has a first and second surface, in which the first surface has a concave curving surface indenting toward the image sensor to adapt at least a portion of the convex curving surface of the first lens.

Abstract: An optical lens system comprises, in order from the object side to the image side: a first lens element with a positive refractive power having a convex object-side surface, one of the object-side surface and an image-side surface being aspheric; a stop; a second lens element with a negative refractive power having a concave object-side surface, one of the object-side surface and an image-side surface being aspheric; a third lens element with a positive refractive power having a concave image-side surface, one of an object-side surface and the image-side surface being aspheric. Focal lengths of the first, second and third lens elements are f1, f2, f3, respectively, they satisfy the relations: 0.4<|f1|/|f2|<1.0; 0.5<|f2|/|f3|<1.3. If |f1|/|f2| and |f2|/|f3| satisfy the above relations, it can provide a wide field of view and improve the resolution. Contrarily, the performance and resolution of the optical lens system will be reduced.

Abstract: A single-focal-length imaging lens system achieves focusing by, while keeping first and third lens groups stationary relative to the image plane, moving a second lens group along the optical axis. The second lens group includes a positive lens element. The third lens group includes an aspherically shaped lens element having an inflection point at a position other than the intersection with the optical axis. The first and second air lenses formed by the intervals between the first and second and between the second and third lens groups have negative and positive refractive powers respectively. The conditional formula 0?|Fi1/Fi2|?|Fm1/Fm2|?10 is fulfilled (Fi1 and Fi2 representing the focal lengths of the first and second air lenses, respectively, when focusing on the infinite object distance; Fm1 and Fm2 representing the focal lengths of the first and second air lenses, respectively, when focusing on the closest object distance).

Abstract: An object of the present invention is to provide illumination optics that enables improvement in brightness and reestablishment of an irradiation state which is provided with illumination light and which corresponds with a display area, and is to provide illumination optics including a first fly-eye lens and a second fly-eye lens where emission light from the first fly-eye lens enter, wherein at least one of lens elements configuring the second fly-eye lens covers an irradiation area smaller than an irradiation area provided by the second fly-eye lens.

Abstract: A directional light distributing optical element includes a light incident surface and a light emission curved surface. The light incident surface receives a light emitted by a light source. The light emission curved surface and a first plane are intersected to form a first curve. The first curve has a plurality of first curve segments, and each first curve segment includes at least three first tangent points. After passing each first tangent point along a connecting line of the light source and each first tangent point, the light exits along a first axis, and an included angle formed between the first axis and an optic axis is greater than ?15° and smaller than 15°. Thus, the light after passing the directional light distributing optical element forms a one-dimensional directional light.

Abstract: A method for designing an objective lens includes: designing a first objective lens, having no annular zone formed on an incident surface on an opposite side to an optical-disc-facing side according to a first optical design with which a laser beam is condensed on a layer between first and second signal recording layers of an optical disc, under conditions including a third temperature between first and second temperatures, and including a third wavelength between first and second wavelengths; and designing a second objective lens, having an annular zone formed on the incident surface of the first objective lens, according to a second optical design with which the laser beam is condensed on the second signal recording layer under the conditions including the second temperature and wavelength the annular zone having such an aspheric coefficient that spherical aberration becomes smaller than that of the first objective lens.