Abstract: A design structure is provided in the effective luminous region of a lamp device. Moreover, there is provided a unit which allows the optical path of a reflected light from a reflector to avoid the design structure is provided on the reflector. Therefore, the design structure can be positively provided in the effective luminous region of the lamp device, without affecting the light distribution, thereby increasing the degree of freedom in designing of the lamp device.

Abstract: Lenses for lamps can improve the quality of the light emitted through lens by interacting with the light bulb. Photoluminescent dyes as well as non-photoluminescent dyes may be incorporated into a polycarbonate lens in order to shift the chromaticity of the light source. Further, design features such as grooves or protrusions may be incorporated into the lens to allow light produced by the photoluminescent material to escape the lens and be added to the emitted beam to further shift the chromaticity. The emitted beam is of a legal color and intensity as defined per the SAE J578 and SAE J1383 standards. The lighting performance may also be improved in such manner as reducing discomfort glare, increasing brightness or producing a beam that enhances road visibility at night to the human eye.

Abstract: A headlight reduced in size and ensuring sufficiently high efficiency is provided. The headlight includes a light source, a cylindrical condenser lens surrounding the light source from its periphery to transmit light incident from the light source, and a reflector surrounding the light source and the cylindrical condenser lens from their backsides to reflect the light transmitted through the cylindrical condenser lens frontward.

Abstract: The present invention relates to a headlight device comprising in particular a light source, a mirror (80) exhibiting a reflecting surface and a transparent optical deflection element positioned in front of the mirror (80), the mirror (80) being capable of interacting with the light source in order to generate a beam bounded by a line of interruption, and the deflection element being capable of providing a horizontal displacement of the light without modifying the vertical distribution of the latter, the said headlight device being characterised in that it comprises and at least one detachment element (81) arranged on at least one of the surfaces of the mirror (80) or of the optical deflection element reached by the light to obtain a line of interruption (71;72) of the light beam that is not flat.

Abstract: A lens (2) disposed in front of a lamp housing (11) has a light transmitting portion (2a) thereof zoned at the rear side into a central section (X) and lateral sections (Y) at both sides thereof, the central and lateral sections (X, Y) being additionally divided into blocks (A, B, C, D, E, F, G), respectively, and prism elements (p) in the blocks are configured so that those (p) in the central section (X) control reflected light from a reflector (12) as reference light, and those (p) in the lateral sections (Y) control direct light from a light source bulb (10) as reference light, thereby providing illumination ranges (J, K) within a light distribution range (LDR) conforming to a light distribution specification (S).

Abstract: A side mirror cover for allowing flickering or illumination of lamps to be visible from relatively a wide range is provided. The side mirror cover has a mirror cover body and a cover lamp. The lamp has a lamp housing having plural light emitting elements and a translucent lamp cover for covering the elements. The housing has a curved first corner section for closing up a part of the through hole and a first principal portion for closing up the remainder thereof. The lamp cover has a second corner section facing the first corner section and a second principal portion facing the first principal portion. The light emitting elements include first LEDs and second LEDs for emitting light toward the front and the side of the vehicle, respectively. The inner surface of the lamp cover has a projected portion facing the second LED, and the inner surface of the second corner section has concavities and convexities for reflecting light.

Abstract: The present invention is a vehicular combination marker/clearance lamp for trucks and trailers using a reduced number of light-emitting diodes and an optics design using total internal reflection to produce the light intensity and angular distribution required by the Department of Transportation. The present invention accomplishes this goal by utilizing a one-piece optical system. The system possesses a collimating lens, ribbed structures, and a modified conical shape, which will concentrate and distribute the light produced by the light-emitting diodes.

Abstract: A vehicular lamp employs a single, high-flux light emitting diode as a light source, and is capable of performing stop, tail, turn and marker functions. The vehicular lamp can satisfy the Federal Motor Vehicle Safety Standard 108, as well as Society of Automotive Engineers Standards J585, J1395, J1398 and J592.

Abstract: The present invention relates to an indicator lamp for a motor vehicle comprising a plurality of light sources (10) and optical processing means (16, 18, 20) able to straighten out the light emitted by the light sources (10) so that it is propagated in a direction essentially parallel to a general direction of emission (X), the optical processing means (16, 18, 20) comprising, in association with each source (10), a first element (12, 16, 18) able to distribute the light in a plane (YZ) essentially perpendicular to the general direction of emission (X), in an essentially uniform way onto a second, generally plate-shaped, element (14, 20) able to straighten out the incident light towards the said general direction of emission (X).

Abstract: A multi-ocular light composed by using a multi-ocular lens integrating a plurality of lenses and comprising one illumination light source for said multi-ocular lens, and a reflector mirror for distributing light from this single illumination light source to said respective lenses, wherein a signal light source is provided at the back of said multi-ocular lens to correspond to at least one lens of this multi-ocular lens, in order to assure the illumination function when said illumination light source is turned on, and the signal function when said signal light source is turned on.

Abstract: A vehicle indicator lamp having a transparent cover that performs horizontal light radiation at a wide angle in which a reflecting surface of a reflector is formed so as to diffusion-reflect the light from a filament of the light source into a forward direction. Horizontal deflection lens portions are formed on the center area of the transparent plain cover and near the lamp's optical axis so as to horizontally deflection-permeate the direct light from the filament in a direction away from the lamp's optical axis.

Abstract: A vehicle lamp that uses a special LED made of: translucent block body, an LED chip embedded in the translucent block body, a semi-spherical shape condenser lens provided on the front end surface of the translucent block body and positioned in front of the LED chip, and a reflector provided inside the translucent block body and forwardly reflects the light from the LED chip. The vehicle lamp includes a front lens disposed in front of the special LED so that the front lens is positioned where the direct light from the LED chip and the reflection light reflected by the reflector start to intersect with each other.

Abstract: A vehicle lamp such as a rear combination lamp comprising: a reflex reflector lens that is fitted in a front lens of the lamp so as to reflect the light from the outside the vehicle lamp back to the outside, and a light reflector that is formed in the front lens so as to face the reflex reflector lens and to entirely reflect the light from a light source toward the light source. The vehicle reflex reflector lens is made of a material that has a lower heat resistance than the front lens.

Abstract: A lane mark irradiation lamp forming a pair of light distribution patterns on left and right sides of the road surface ahead of a vehicle. The light distribution patterns are formed so as to extend along the lane marks provided on the road, and the luminous intensity distribution of the light distribution patterns in lateral direction in a first angle position that is in a downward direction at a predetermined angle with respect to a longitudinal axis of the lamp is set so as to have peaks on both sides of such a longitudinal axis.

Abstract: A headlight allowing easy adjustment of a delicate light distribution pattern during manufacturing is provided. The headlight includes a light source, a reflector surrounding the light source from its backside to reflect light incident from the light source frontward, and a front lens located in front of the light source and the reflector. The front lens is provided with at least two portions different in light transmission characteristic from each other.

Abstract: A mirror assembly security system for a vehicle includes an exterior mirror assembly and a light module removably positioned within the exterior mirror housing. The light module is moisture impervious and includes an enclosure, a light-emitting opening in the enclosure, a light source in the enclosure radiating light through the light-emitting opening, and a cover for the light-emitting opening adapted to direct the light from the light source to an area adjacent the vehicle to create a security area. The light source may be supported by a pair of electrical contacts provided on the inner surface of the enclosure. The enclosure wall supporting the electrical contacts is preferably flexible, in order to allow the light source to be captured by the contacts. Attachment of the cover adds rigidity to the enclosure to prevent further flexure of the enclosure wall in order to firmly retain the light source.

Abstract: An exterior rearview mirror assembly security system for a vehicle includes an exterior mirror assembly with a security light assembly which projects a pattern of light from the exterior mirror assembly on a ground area adjacent a door of the vehicle in order to create a lighted security zone in the area. The security system further includes a control, which is responsive to approach by a person to the vehicle and actuates the security light assembly to generate the pattern of light from the exterior mirror assembly in order to provide the lighted security zone adjacent the side of the vehicle equipped with the exterior rearview mirror assembly.

Abstract: A lens (2) disposed in front of a lamp housing (11) has a light transmitting portion (2a) thereof zoned at the rear side into a central section (X) and lateral sections (Y) at both sides thereof, the central and lateral sections (X, Y) being additionally divided into blocks (A, B, C, D, E, F, G), respectively, and prism elements (p) in the blocks are configured so that those (p) in the central section (X) control reflected light from a reflector (12) as reference light, and those (p) in the lateral sections (Y) control direct light from a light source bulb (10) as reference light, thereby providing illumination ranges (J, K) within a light distribution range (LDR) conforming to a light distribution specification (S).

Abstract: A blink lamp is arranged on a comer of a motor vehicle, at a side next to a headlight, and has a housing with a light-transmissive cover panel covering the housing. A prismatic light element is arranged inside the blink lamp on a side adjacent to the headlight and adjacent to the cover panel. The prismatic light element bends beams of light coming directly from the light source toward the cover panel and toward the headlight.

Abstract: An optical unit for an aircraft warning light comprising an array of LEDs, the unit comprising a transparent plastics molded body having first and second opposing faces and being provided with optical means on its first and optionally also its second face to propagate fractions of light emitted from the LEDs in selected directions in accordance with a predetermined angular distribution. The optical means may, for example, take the form of discrete convex lenses, cylindrical aspherical lenses, prisms or total internal reflection structures and combinations thereof selected according to the emission requirements for the warning light. The optical unit will therefore differ depending on whether it is for use on a navigation light or an anti-collision light and will generally be spaced at a predetermined, fixed distance from the LED array.

Abstract: The present invention relates to a component for a motor-vehicle lighting or indicator device. According to the invention, it consists of a transparent material within which light-diffusion foci consisting of local discontinuities are situated only at predetermined locations in order to diffuse the light emitted by a light source associated with the lighting or indicator device.

Abstract: An upwardly deflecting prism lens element is formed horizontally across a front-side surface of a focusing lens. The light-dark ratio of a borderline in a low-beam luminous intensity distribution pattern is reduced by upwardly deflecting a light beam, which is transmitted through the focusing lens and illuminated forwardly from the lens element. Chromatic aberration is not produced by the light beam transmitted through the lens element and radiated in the forward direction.

Abstract: A vehicle puddle light assembly is provided in an opening formed in a body panel of a vehicle. A socket including a housing and at least one contact coupled to the housing is disposed within the opening and coupled to the body panel adjacent the opening. A lamp is coupled to the contact within the housing. A lens is coupled to the socket outboard of the lamp. The lens has an opaque upper portion and a transmissive lower portion having a plurality of facets formed therein for projecting light from the assembly and a predominantly downward and outboard direction. The housing includes a reflective upper portion for directing radiation from the lamp toward the transmissive portion of the lens and a reflective lower portion for directing radiation from the lamp toward a reflective surface of the lens formed inboard of the opaque upper portion. The radiation is then redirected toward the reflective upper portion of the housing and then toward the transmissive portion of the lens.

Abstract: In a lighting system for motor vehicles, light from a HID or MPXL lamp is collected by a collector which surrounds the light source at least partly and is guided further to a separator of optical waveguide material, which separator forms a desired light beam via a specially shaped light outlet surface so as to obtain as high as possible a light output.

Abstract: A motor vehicle headlight comprises a single light source cooperating with fixed optical means to produce a fixed beam which is generally spread widthwise and which is such as to perform two functions selectively, namely to enhance a dipped passing beam produced by another headlight and to produce a further beam, such as a foglight beam, with a specific top cut-off. The beam comprises at least two regions which are bounded by at least two portions of the top cut-off line, these portions being arranged at different levels. The invention also relates to a pair of headlights of this type, one on the right of the vehicle and one on the left.

Abstract: A vehicular lamp lens having integrated lens members with a boundary therebetween. The front surface of the boundary portion side of at least one of the lens members is displaced in the rearward direction as the surface becomes closer to the boundary.

Abstract: A vehicular lamp having an inner lens is described. In an implementation, an annular wall 18A surrounding an optic axis Ax of a reflector 14 is formed on the inner lens 18 disposed between am outer lens 16 and a reflecting surface 14a of the reflector 14. The inner lens 18 is divided by the annular wall 18A into an internal zone 18B and an external zone 18C which may be different from each other in convex-concave lens shape. The internal zone 18B may be formed of a translucent lens, and a plurality of grid-type lens elements 18Cs may be formed over the entire rear surface of the external zone 18C. Thus, an observer viewing the interior of a lighting chamber from a location in front of the lamp will see that the internal zone 18B and the external zone 18C, which are divided by the annular wall 18A, are significantly different. The configuration of elements provides a vehicular lamp that is visually attractive.

Abstract: A vehicular lamp fixture, such as an indicator lamp, having an improved external appearance and originality. Diffusion lens elements are arranged at predetermined positions offset from a lamp fixture optical axis of an inner lens. The lens element optical axes of the diffusion lens elements pass through a boundary that divides the reflective surface of a reflector into an inner peripheral area and an outer peripheral area, each of which approaches a paraboloid of revolution centered on the lamp fixture optical axis. The reflective surface is formed as a curved surface curving forward of the paraboloid of revolution P. Light from a filament is irradiated as convergent light in a radial direction onto the diffusion lens elements, causing the diffusion lens elements to shine brightly and causing an image of the filament to appear reflected at central positions of the diffusion lens elements when seen from the front of the lamp fixture.

Abstract: A vehicle lamp such as a rear combination lamp comprising: a reflex reflector lens that is fitted in a front lens of the lamp so as to reflect the light from the outside the vehicle lamp back to the outside, and a light reflector that is formed in the front lens so as to face the reflex reflector lens and to entirely reflect the light from a light source toward the light source. The vehicle reflex reflector lens is made of a material that has a lower heat resistance than the front lens.

Abstract: A vehicular headlamp utilizing a light source bulb of the H4 type and which provides a low-beam light distribution pattern which makes it easy for the driver to drive and reduces the possibility of oncoming drivers being dazzled by glare. A light source bulb is securely supported by a reflector so that left and right upper edges of a shade are located at substantially the same height and an axis of a filament is upwardly offset from an optical axis of the reflector at a predetermined angle. A reflecting surface of the reflector is provided with a downward deflective reflection zone which downwardly deflects and reflects the light that has traveled from the filament past the right upper edge of the shade and impinged on a traveling-lane-side reflection zone.

Abstract: A vehicle light assembly includes a lens cover from which light emanates. A light shaping surface microstructure is carried in a portion of the light assembly. The microstructure can be incorporated into many different surfaces of the light assembly such as a surface of the lens cover, a surface of a macro-optical structure on the lens cover, or on a reflective surface of the assembly. The microstructure homogenizes and directs light emanating from the light assembly via reflection or transmission to provide a smooth, continuous pattern of light having a predetermined distribution shape or envelope and a predetermined directionality.

Abstract: A vehicle lamp includes: a lamp chamber defined by a lamp body and a colorless transparent front lens; a light source disposed in the lamp chamber; and a printed sheet disposed inwardly of the front lens. The printed sheet includes a colorless transparent sheet main body of synthetic resin having a pattern consisting of a predetermined colored transparent layer printed on an internal surface of the front lens. The colored transparent layer and a convex three-dimensional colorless transparent layer are formed in a laminated fashion as a lower layer and an upper layer, respectively, on an external surface of the sheet main body. A plating-like printed layer and a light shielding layer are formed in a laminated fashion as a lower layer and an upper layer, respectively, on an internal surface of the sheet main body at a location matching the location of the convex three-dimensional colorless transparent layer.

Abstract: An indicator light comprises a source, an optical plate adapted to straighten out the incident light towards an average direction generally parallel to an optical axis, and a flux-distributing and recuperating cup interposed between the source and the plate in order to distribute the light over the inner surface of the plate. According to the invention, the optical plate has a height and a width of the same order of magnitude and possesses optical configurations having varied coefficients of transmission of the light, and the cup provides a given distribution of the light, both in the horizontal direction and in the vertical direction, which takes account of said coefficients. As a result, an illumination is obtained at the exit from said plate which is essentially constant in the horizontal direction as well as in the vertical direction.

Abstract: To provide a vehicle lamp having a high quality lens and a method for manufacturing the same and make it possible to reliably separate a pre-molded lens member while being securely held in the movable die during composite lens molding in a multi-color molding process.

Abstract: Lighting optics is provided for lights of vehicles, preferably motor vehicles. The lighting optics has a light-refracting lens element that is disposed in the path of rays of at least one light. The lens element has at least one aperture through which a portion of the rays of the light passes without undergoing refraction.

Abstract: An exterior rearview mirror assembly security system for a vehicle includes an exterior mirror assembly. The exterior mirror assembly includes a security light assembly, which projects a pattern of light from the assembly on an area adjacent a door of the vehicle in order to create a lighted security zone in the area. The security light assembly includes an enclosure, with a light-transmitting opening in the enclosure, and a light source for radiating light through the light-transmitting opening. The security light assembly also includes a cover for the light-transmitting opening, which comprises an optical lens having at least one non-planar optical surface.

Abstract: A vehicle lamp can include a tube-like lamp element that has an aperture, a reflector having a focus located approximately at the aperture, and a front lens. The lamp can be disposed in a vehicle body space that has a small width from the front view and a small depth from a side view of the vehicle body. A blind or shade is not necessary to cover non-aesthetic portions of the lamp. The lamp can be tube-like in shape and can include an optical system that has at least two ellipse group reflecting surfaces that are combined to form a multi-reflex optical system. An aperture can be formed by the reflecting surfaces to allow light rays to be guided outside of the lamp. A light source is preferably located on a common first focus of the at least two ellipse group reflecting surfaces. One of the ellipse group reflecting surfaces can have a longer focal distance than, and a different longitudinal direction from, those of other ellipse group reflecting surface(s).

Abstract: A multi-chamber lamp has a lamp housing with a plurality of reflectors. A closure pane is provided on the lamp housing. An intermediate pane, located between the reflectors and the closure pane extends over an entire light emergence plane of at least one reflector. The closure pane as well as the intermediate pane are at least partially free of optical function. The intermediate pane supports a shield device for the light source associated with the at least one reflector, which is surrounded by an optics-free area. A cover apparatus completely encompasses the at least one reflector provided with the intermediate pane and covers also a peripheral rim of the intermediate pane as well as shields an interior of the lamp housing from view from the outside.

Abstract: The reflective surface of a reflector 16 is divided through steps into a plurality of vertically elongated reflective surface elements. In each of those reflective surface elements, the light incidence section to which the output light of a light source bulb is applied is made up a convex cylindrical curved surface and a concave cylindrical curved surface which are arranged substantially in parallel with the step adjacent to the light incidence section. Accordingly, when the lamp is turned on, and the reflector is observed from the front, the light incidence sections function as follows; that is, the apex portions of the cylindrical curves surfaces look glittered as bright sections. Therefore, the reflective surface looks more sparkling.

Abstract: An indicator light for a motor vehicle has a point source, an intermediate screen which receives the light directly from the source, and a cover glass outside the screen. The intermediate screen comprises a series of optical cells, each of which has, on an internal face, a curved surface for straightening and spreading the light. Each cell further has, on an outer face, a set of at least two flat facets which are oblique with respect to a plane of the intermediate screen.

Abstract: A grid defining illumination cells having areas to pass light from a source for use in generation of a lines, wherein the grid is defined by first lines extending about one axis defined by the source, and second lines emanating from the axis to intersect first lines, each cell having four edges defined by successive of first lines and successive of second lines, the cells having one of the following: i) equal areas ii) areas that increase in direction away from the source.

Abstract: A lamp for vehicle that includes a light source, a housing, a reflector and a lens is disclosed. The lens is made by the process that includes the steps of (a) assuming an imaginary plane with a cross hatching pattern made of crossing groups of plural lines disposed in parallel at a constant pitch, (b) deforming the imaginary plane by a desired shape consisting of a convex surface, a concave surface or a combination of both surfaces, so that the cross hatching pattern is deformed into a process surface, and (c) processing a lens cut in accordance with the cross hatching pattern when the process surface is orthographically projected onto the lens surface. The deformation given to the imaginary plane is performed so that the maximum pitch of the cross hatching pattern orthographically projected onto the lens surface is 1.5 times or more and 20 times or less the minimum pitch. The lens cut may have curvatures of the same diffusion coefficient regardless of the pitch of the cross hatching pattern.

Abstract: A double-focus lens is disclosed in which double-focus lens cuts (for example, cuts in which elements of the lens cuts formed on one of the surfaces of the lens include convex cuts in a first direction and concave cuts in the direction substantially perpendicular to the first direction) are formed on at least a portion of the lens. A vehicular lamp device can be constructed using the double-focus lens as an outer lens. Accordingly, a vehicular lamp device with a feeling of three-dimensional depth can be realized by using a lens that forms focal points in two locations, i.e., oil the front side of the lens and on the back side of the lens, without sacrificing light distribution characteristics.

Abstract: A vehicle lamp having a hollow body lens unit constructed by integrally forming a lamp body and a front lens which constitute a lamp chamber, a light source provided in the body lens unit, and a diffusion step such as a cylindrical step having step elements, each of which has constant directivity, the diffusion step being provided on the outer surface of the lens portion of the body lens unit. The step elements of the diffusion step on the outer surface of the lens portion are lined up in a predetermined direction and each have directivity, so that the mud and dust do not easily stick to each step element.

Abstract: A lighting module for a motor vehicle headlight, in which light from a light source is received by the input end of a light guide having a plurality of oblique facets, which are reflective by total reflection and cooperating with lenses. The light guide comprises a set of transparent strips stacked together, and the module includes a reference member comprising a first portion which defines a horizontal reference plane, and a second portion which defines a vertical reference plane. The stacked transparent strips are abutted against these two portions of the reference member in a predetermined position on the longitudinal axis of the light guide, so that their facets will cooperate with the lenses to project in the emission direction images corresponding to the facets.

Abstract: A headlight for a vehicle operating in accordance with the projection principle, the headlight has a reflector, a light source, a lens through which a light reflected by the reflector passes, at least one partially light-permeable element which surrounds the lens at least over a part of its periphery, so that light which is emitted by the light source and not engaged by the reflector passes through and is collected by the at least one element, wherein, the reflector and the lens being formed so that light which is reflected by the reflector and passes through the lens forms an upper bright-dark limit, the element being formed at least locally as a fresnel lens with ring-shaped optical profiles, and further optical profiles arranged at least in a part of a beam path of the light passing through the element and deviating the light so that it illuminates a region in front of the vehicle above the bright-dark limit formed by the light reflected by the reflector and passing through the lens.

Abstract: There is provided a lamp comprising a light source, a horizontal double ellipsoidal reflector composed of two reflecting surface units joined horizontally in opposing relation to each other and each formed from a spheroid, and aspheric lenses. Each of the two reflecting surface units is formed by cutting, radially around the center axis of the light source, a portion from the spheroid having a first focal point located on the center axis and adjacent the light source and a second focal point located on a line passing through the first focal point and tilted appropriately from the light-source center axis such that the cut portion spans, around the center axis, a range of 5.degree. to 9.degree. in either vertical direction from a horizontal line. The aspheric lenses are provided horizontally to correspond to the respective second focal points of the reflecting surface units of the ellipsoidal reflector and converge reflected light beams from the respective reflecting surface units.

Abstract: A mirror assembly security system for a vehicle includes an exterior mirror assembly and a light module removably positioned within the exterior mirror housing. The light module is moisture impervious and includes an enclosure, a light-emitting opening in the enclosure, a light source in the enclosure radiating light through the light-emitting opening, and a cover for the light-emitting opening adapted to direct the light from the light source to an area adjacent the vehicle to create a security area. The light source may be supported by a pair of electrical contacts provided on the inner surface of the enclosure. The enclosure wall supporting the electrical contacts is preferably flexible, in order to allow the light source to be captured by the contacts. Attachment of the cover adds rigidity to the enclosure to prevent further flexure of the enclosure wall in order to firmly retain the light source.

Abstract: A vehicle lamp has a housing, a light-transmissive shield covering the housing that extends across a corner area of the vehicle, at least one lamp chamber in the housing in which a light source is positioned, and a Fresnel lens having concentrically arranged prism rings located between the light source and the light-transmissive shield adjacent to the light-transmissive shield in at least partial area. The Fresnel lens has at least one curved partial area, in order to make manufacturing as simple as possible while achieving an optimal illumination and maintaining proper light distribution. The Fresnel lens is comprised of a first curved partial area having a center of the concentrically arranged prism rings and a second partial area extending up to a side area of the lamp chamber. The partial areas have differing surface geometries and are separated from each other by vertical separating lines.

Abstract: A vehicular lamp including a lamp body having a U-shaped recess portion defining a lamp chamber and an opening; a light source disposed in the lamp chamber; a lens covering the opening of the lamp body; a fish-eye lens portion formed of at least one fish-eye lens; a cylindrical lens portion formed of at least one cylindrical lens, the fish-eye lens portion and the cylindrical lens portion arranged on a surface of the lens with a thickness of the fish-eye lens portion being substantially equal to a thickness of the cylindrical lens portion.