Abstract: There are provided an operation microscope and an observation prism which are capable of conducting a high-visibility observation with less glare. The operation microscope includes an objective lens opposed to an eye to be operated, a front lens which is provided between the eye to be operated and an anterior focal point of the objective lens and condenses illumination light to illuminate an interior of the eye to be operated, and the observation prism disposed near the front lens to observe fundus and its surroundings of the eye to be operated. An oblique surface (refractive surface) of the observation prism has a curved shape in which the curved shape shows a certain negative curvature in a direction to an intersection with a refractive surface. Therefore, aberrations caused on images of entrance pupils of an observation system and an image of an exit pupil of an illumination system can be corrected.

Abstract: A prism unit, which is capable of firmly fixing a plurality of prism parts in a small space, and a laser device, which is capable of enhancing output power of laser light with use of the prism unit, are provided. For this purpose, a prism unit (28) includes a plurality of prism parts (35), which refract incident light (21), and a fixed part (36) which is fixed to or formed integrally with at least two of the plurality of prism parts. Further, a laser device includes the prism unit (28), and only a wavelength in a desired range out of a plurality of oscillation wavelengths is selectively oscillated by the prism unit.

Abstract: A light guide comprising three guide sections and a light coupling element between the light guide sections. The light coupling element having an internal polarizing surface for reflecting light of a predetermined polarization state. Each light guide section has an entrance aperture, an exit aperture and at least first and second guide walls defining a light guide direction.

Abstract: A solution for fabricating a light diffusing sheet-like device capable of emitting light with superior brightness, that is a high brightness diffuser. The high brightness diffuser mainly includes at least two light diffusing pieces with ridge-shape structure arranged thereon, which can be either convex or concave. The convex ridge-shape structure having a plurality of large convex ridges and a plurality of small convex ridges, which are associated with a ridgeline existing in between two adjacent ridges where the large ridge and small are interlace-arranged, and the ridges along with the associated ridgelines can be longitudinally extended to the same direction. The concave ridge-shape structure is constituted the same way as the convex ridge-shape structure is, but having concave ridges. The high brightness diffuser is fabricated by stacking up the two light diffusing pieces and enabling an included angle to be formed between the two ridge-extending directions of the two light diffusing pieces.

Abstract: A polarization recovery system polarizes input light for use with an LCD imager. The polarization recovery system converts light of the wrong polarity to the correct polarity to add to the illumination of the LCD imager. The polarization recovery system may include: (1) an output waveguide that receives polarized light energy from the system; (2) a polarized beam splitter that receives the light energy from the input waveguide, transmitting lights energy of a first polarization type and reflecting light energy of a second polarization type, and (3) a wave plate that modifies the polarization of either the transmitted or reflected light energy to that of the correct polarization. The polarization recovery system may include one or more “gaps” of optically clear material positioned between the optical components to encourage total internal reflection and minimize the loss of the optical energy.

Abstract: A light guide comprising three guide sections and a light coupling element between the light guide sections. The light coupling element having an internal polarizing surface for reflecting light of a predetermined polarization state. Each light guide section has an entrance aperture, an exit aperture and at least first and second guide walls defining a light guide direction.

Abstract: An optical element (1) for reflecting and/or redirecting light rays (L1) entering therein and again emerging therefrom consists of a transparent base body (2) which is so structured and/or formed that, with the formation of reflection surfaces (8) bounding the base body (2), at least a part of the light rays (L1) impinging upon the reflection surfaces (8) upon emergence from the transparent base body (2) are totally reflected, and at least one cover body (9) arranged behind the reflection surfaces (8). The reflection surfaces (8), and the surfaces of the cover body or bodies (9) towards the reflection surfaces, are adapted to one another such that between them there remains a thin gap (10) or only point contacts exist.

Abstract: A truncated triangular prism has an entrance and an exit face perpendicular to each other and a reflecting face inclined at an angle ? to the entrance face where ? is about 135°??B, and where ?B is the external Brewster angle for the material of the prism at the wavelength of radiation to be reflected by the prism. A beam of p-polarized radiation directed into the prism through the entrance face at the Brewster angle is totally internally reflected from the reflecting face and leaves the exit face at the Brewster angle and at an angle of ninety degrees to the direction at which the radiation enters the prism.

Abstract: An optical switch (10) includes a housing (3), an input port (4), an output port (5), a switching element (6), a holder (7), and a driver (63). The holder holds the input and output ports in alignment with one another and is assembled with the switching element. The switching element includes an optical component assembly (61) and a rotating mechanism (60). The optical component assembly is fixed on the rotating mechanism and is brought to move between a top stopper (85) (an upward position), wherein the optical component assembly is out of optical paths running between the input port and the output port, and a bottom stopper (86) (a downward position), wherein the optical component assembly is in the optical paths. The optical component assembly includes a prism (612), which redirects optical paths passing through it, thereby effecting switching between the input and output ports.

Abstract: Disclosed is an optical component, which comprises a prism element adjacent to a lens element, where the two elements are separated by a small air gap. In disclosed embodiments, the elements have adjacent and parallel surfaces which are substantially planar and which, with the small air gap, operate through Total Internal Reflection (“TIR”) to direct light beams that strike the planar surfaces. Light beams that strike at less than the critical angle are internally reflected, while light beams which strike at greater than the critical angle pass through. The TIR surfaces thereby separate the desired optical signals from the spurious ones. The combined TIR prism lens operates as a single and integrated component which directs desired light beams to a reflective optical processing element such as a Spatial Light Modulator and which focuses the processed light beams as they leave the combined TIR prism lens.

Abstract: A MEM device in accordance with the invention comprises one or more movable micro-structures which are preferably ribbon structures or cantilever structures. The ribbon structures or cantilever structures are preferably coupled to a substrate structure through one or more support regions comprising a plurality of anchor support features and a plurality of post support features. The MEM device is preferably an optical MEM device with a plurality of movable ribbon structures each being supported by opposing ends through support regions each comprising a plurality of anchor support features and a plurality of post support features. In accordance with the method of the embodiments, the positions of the anchor and post support features, the number of anchor and support features and the spacings between the support features can selected during fabrication of the device to determine an operating condition of the MEM device.

Abstract: A fingerprint sensor used for a fingerprint recognition system comprises a first prism or prism array including a first surface which a human finger is placed and a second surface; a lamp for irradiating the finger with light; a second prism or prism array for refracting the light which is reflected from the finger and subsequently passes through the second surface in such a way that the light refracted by the second prism or prism array travels along a path closer to a normal to the first surface of the first optical component than a path of light without refraction by the second prism or prism array; and an image sensor for receiving the light refracted by the second prism or prism array and converting fingerprint information for the finger into an electric signal.

Abstract: Systems and methods for adjusting optical path length of an optical path are provided. The systems and methods can be used to controllably adjust optical path length in an external cavity laser. A representative optical path having a first end and a second end comprises a first transparent refractive element located in the optical path between the first end and the second end. The transparent refractive element is adjustable to adjust the optical path length of the optical path without changing the physical distance between the first end and the second end. A representative method includes introducing a transparent refractive element into the optical path and adjusting the transparent refractive element to change the optical path length without changing the physical distance between the first end and the second end of the optical path.

Abstract: An illuminating apparatus has a light source emitting illumination light; and a prism having a plurality of reflecting surfaces and reflecting the illumination light from said light source by the reflecting surfaces to thereby bend an illumination optical path at an obtuse angle.

Abstract: A lamp assembly including a number of light sources each utilized in conjunction with an optical element. The optical elements include a body of light transmitting material which further includes a top surface, a bottom surface, a front surface and a plurality of facets. The facets receive light through the front surface and reflect light through the top surface. The assembly further includes a manifold defined by the optical elements. When viewed in a direction toward the top surface, a majority of the optical elements have a common shape, preferably a pie wedge shape.

Abstract: In an optical sheet 10 having a prism surface 16 formed by providing unit prisms 14 on the upper surface of a transparent base material 12, a coating layer 18 is provided on the reverse surface of the transparent base material opposite to the prism surface 16, spherical beads 20 are arranged projecting from the surface of the coating layer 18 by 1 to 10 &mgr;m in height, and the coating layer 18 is brought into contact with the flat and smooth surface 22A of the light-transmissive material 22 through the spherical beads 20 which are put between them. The spherical beads are 1 &mgr;m or less in half bandwidth of the distribution of particle diameters and are made uniform in height projecting from the coating layer 18.

Abstract: Disclosed is an optical fingerprint acquisition apparatus capable of reducing an image distortion and a size of an optical system by deforming the shape of a prism. The prism according to the invention includes a fingerprint contacting surface to be touched by a fingerprint of a person, a totally reflecting surface facing the fingerprint contacting surface with an angle &thgr; for totally and inwardly reflecting the light scattered from the fingerprint in contact with the fingerprint contacting surface, a primarily projecting/re-incident surface linking the fingerprint contacting surface to the totally reflecting surface with an angle &phgr; for primarily projecting the light totally reflected from the totally reflecting surface so as to be re-incident from outside, and an ultimately projecting surface facing the primarily projecting/re-incident surface for ultimately projecting the light re-incident to the primarily projecting/re-incident surface toward outside.

Abstract: An extremely compact prism optical element, image observation apparatus and image display apparatus which are capable of providing an observation image that is clear and has minimal aberration and minimal distortion even at a wide field angle. Light rays emitted from an image display device (7) enter an ocular optical system (12) through a fourth surface (6) and are totally reflected toward an observer's pupil (1) by a third surface (5). The reflected light rays are reflected by a first surface (3) disposed immediately in front of the observer's pupil (1) and then reflected toward the observer's pupil (1) by a second surface (4). The reflected light rays pass through the first surface (3) and are projected into an observer's eyeball (15) with the observer's iris position as an exit pupil (1).

Abstract: A dichroic prism 10 according to the present invention comprises first to fourth right angle prisms 12, 14, 16 and 18 respectively having first side faces 28, 34, 40 and 46, and second side faces 30, 36, 42 and 48, the side faces being arranged perpendicular to each other. A second bonded face 22 and a fourth bonded face 26, each having a dichroic film for a second color light, are arranged on the same plane. The first bonded face 20 and a third bonded face 26, each having the dichroic film for a first color light, are deviated by a predetermined distance. The distance of this deviation is adjusted so that an image formed by the light having reference image information corresponds to the image of the reference image information. The light is made incident on and reflected by the first bonded face and the third bonded face. Therefore, an appropriate image quality can be obtained without depending on a right angle precision.

Abstract: The present invention relates to a high-performance image-forming optical system made compact and thin by folding an optical path using reflecting surfaces arranged to minimize the number of reflections. A prism member 10 has a first entrance surface 11, first to fourth reflecting surfaces 12 to 15, and a first exit surface 16. An optical path incident on the first reflecting surface 12 and an optical path reflected from the second reflecting surface 13 form intersecting optical paths. An optical path incident on the third reflecting surface 14 and an optical path reflected from the fourth reflecting surface 15 form intersecting optical paths. At least either one of the first reflecting surface 12 and the second reflecting surface 13 and at least either one of the third reflecting surface 14 and the fourth reflecting surface 15 have a rotationally asymmetric curved surface configuration that gives a power to a light beam and corrects aberrations due to decentration.

Abstract: An image projecting apparatus has optical switches in first optical switch unit arranged in a square matrix arrangement, and a second optical switch unit of optical switches in single file for selectively reflecting the monochromatic lights reflected from the first optical switch unit. A light source irradiates a plurality of monochromatic lights of different wavelengths and the monochromatic lights are passed through the optical switches and a square beam generator such that they are incident on a panel unit to realize a monochromatic color stripe of a predetermined size. Light utilization increases through the use of first and second optical switch units, and overlapping between monochromatic color stripes can be prevented through the use of digital micromirror device (DMD) panel or liquid crystal on silicon (LCOS) panel of fast responsiveness.

Abstract: The invention relates to an optical arrangement provided for a spectral fanning out of a light beam (1), preferably the detection beam path of a confocal microscope, especially for the subsequent splitting of the fanned out beam (2) out of the dispersion plane thereof. The optical arrangment is also provided for detecting the fanned out spectral regions (4), whereby the incoming light beam (1) is focused on a pinhole (7). The invention is characterized in that the pinhole (7) has a polygonal passageway (8) in order to realize a high dynamic response when the light beam is split into spectral regions (4) or into spectral colors.

Abstract: The present invention relates to a prism diffuser for diffracting and spreading light, and in particular to a prism diffuser for diffracting and spreading light which is capable of spreading light in a certain direction at a wider angle based on a structure combined with a prism capable of diffracting light on a surface of a medium formed of a glass which transmits or reflect light, a film formed of a transparent synthetic resin material or a metallic plate and a diffuser capable of spreading light and diffracting, spreading and transmitting light into two directions or diffracting, spreading and reflecting light in one direction.

Abstract: The present invention relates to an achromatic phase shift device (1) for introducing a wavelength independent optical phase shift in a first optical beam (40) during operation, comprising at least one dispersive element (55k) formed by first refractive means (2k) and second refractive means (4k), the first refractive means (2k) having a first refractive means input plane (6) for receiving the first optical beam (40) and a first refractive means output plane (8) being at a predetermined angle (&bgr;) to each other, the second refractive means (4k) having a second refractive means input plane (10) and a second refractive means output plane (12) being positioned parallel to the first refractive means input plane (6). The device may comprise further pairs (55k) of respective first and second refractive means (2k, 4k). The present invention also relates to an interferometer comprising at least one achromatic phase shift device.

Abstract: An optical coupler includes a housing, and includes first and second optical terminals and a prism disposed in the housing. One terminal is moveable with respect to the other, and the prism maintains an optical alignment between the terminals. Because it includes a prism instead of a more complex and delicate optical assembly, such an optical coupler can often be less expensive and more rugged, and can often have a higher connection density, than prior optical couplers.

Abstract: An optical system with improved boresight stability having optical elements and a beam expander oriented on a chassis, wherein the beam expander is mounted for minimal movement. By minimizing movement of the beam expander, the angular error of a laser beam travelling through the optical system and subject to various angular tilt errors is reduced by an amount inversely proportional to the magnification ratio of the beam expander based on optical principles. In one embodiment the beam expander is mounted on a highly stiff location on the chassis and away from thermal stresses. Another embodiment is to mount the beam expander to a structural support of a higher assembly. The present invention isolates the beam expander from the instability of individual optical elements and from deformation of the optical bench that impairs the performance and diminishes benefits otherwise gained from the optical principles.

Abstract: A TIR prism system for DMD and a projector adopting the same make a loss of incidence light be reduced, and having a small size and light weight. In a TIR prism system having the DMD and for total reflecting the incidence light to a certain direction in accordance with that the DMD is controlled, the TIR prism system of the present invention includes a first prism for receiving the incidence light on a surface set before, refracting the light, and outputting the refracted light, and a second prism coupled to the first prism for receiving the light outputted from the first prism, transmitting the light to the DMD, and outputting the transmitted light after being totally reflected in accordance with that the DMD is controlled, whereby a loss of light energy inside the system can be reduced.

Abstract: The invention provides a reflective optical element which has three or more reflecting surfaces by which a light flux from an object is successively reflected. In an area enclosed by each of the reflecting surfaces, the reference axis intersects at least two times and the light flux forms an intermediate image. The reference axis is a path of the light beam which passes through the center of an object surface, is then reflected by the reflecting surfaces, and passes through a center of a pupil. The reflective optical element satisfies the following condition: 4·f·tan&thgr;<ea wherein &thgr; is a maximum field angle that passes through the pupil in a plane that includes the reference axis, f is a focal length of an optical part between the pupil and an intermediate-image forming surface, and ea is a maximum optical effective diameter of the reflective optical element.

Abstract: An optical system (20) provides a variable dispersion that helps to collect multi-spectral information on an object within the field of view. The system (20) includes at least two sets (24, 26) of optical elements (42x 42y, 44x, 44y) that have minimal deviation of a center wavelength and a non-zero deviation of at least one other wavelength. By rotating the sets of optical elements (24, 26) relative to one another or together, the degree of wavelength dispersion and the direction of the wavelength dispersion can be varied, respectively. By selectively rotating the sets of optical elements, the system also can be operated in a non-dispersed “white light” mode with no net dispersion at the image plane.

Abstract: Systems and methods for adjusting optical path length of an optical path are provided. The systems and methods can be used to controllably adjust optical path length in an external cavity laser. A representative optical path having a first end and a second end comprises a first transparent refractive element located in the optical path between the first end and the second end. The transparent refractive element is adjustable to adjust the optical path length of the optical path without changing the physical distance between the first end and the second end. A representative method includes introducing a transparent refractive element into the optical path and adjusting the transparent refractive element to change the optical path length without changing the physical distance between the first end and the second end of the optical path.

Abstract: In a device and method, the optical path length through an optical element is adjustable with high precision. The optical element has a first segment formed from a first optical material, the first segment having a first face at a first end and a second face at a second end opposing the first face, the second face being non-parallel with the first. The first and second faces are disposed on a beam path. The element also includes a second segment formed from a second optical material, having a third face at a third end and a fourth face at a fourth end opposing the third face, the third face being non-parallel with the fourth face. At least one of the first and second segments is translatable across the beam path so as to change an optical path length through the optical element.

Abstract: An optical element (10, 10′, 10″) for deflecting light beams (18, 19), which enter and re-emerge from the latter, in such a way that their angle of emergence (&ggr;) is limited, in particular for use as a luminaire-cover, having a plate-like core (11, 11′, 11″) of transparent material which on one side is occupied by microprisms (12, 13) that taper—starting from their root (15)—forming furrows (22), wherein all of the top surfaces (14) of the microprisms form the light-entry face and the other side (21) of the core forms the light-emergence face, and wherein the top surfaces (14) of the microprisms are formed convexly or concavely in a continuous or non-continuous manner, and also a method for producing the optical element (10, 10′, 10″).

Abstract: In an optical sheet 10 having a prism surface 16 formed by providing unit prisms 14 on the upper surface of a transparent base material 12, a coating layer 18 is provided on the reverse surface of the transparent base material opposite to the prism surface 16, spherical beads 20 are arranged projecting from the surface of the coating layer 18 by 1 to 10 &mgr;m in height, and the coating layer 18 is brought into contact with the flat and smooth surface 22A of the light-transmissive material 22 through the spherical beads 20 which are put between them. The spherical beads are 1 &mgr;m or less in half bandwidth of the distribution of particle diameters and are made uniform in height projecting from the coating layer 18.

Abstract: The multi-beam scanning device includes first and second light emitting elements that emit first and second light beams, respectively, a polygon mirror that deflects the first and second light beams to simultaneously scan the first and second light beams across an object. A prism having a light entrance portion and a light exit portion is located between the light emitting elements and the polygon mirror such that the first light beam enters the first prism through the light entrance portion and exits from the first prism through the light exit portion toward the polygon mirror. The light exit portion is inserted into the optical path of the second light beam to prevent a part of the second light beam from proceeding toward the polygon mirror.

Abstract: A pair of prisms arranged in a complementary relationship provides for anamorphic magnification and cooperates with a curved refractive element, the later of which generates an aberration that at least partially compensates an aberration generated by the pair of prisms. Examples of the curved refractive element include, but are not limited to, a cylindrical lens, a curved substrate of optical material, a pair of counter-rotatable cylindrical lenses, a fluid-filled cylindrical lens with variable power incorporating a substrate that is deformed by a clamp mechanism over a fulcrum or curved surface, and at least one curved surface of fixed or variable curvature of the prisms, the later of which may be fluid-filled. In one embodiment, a color image is generated as a composite of images from different image modulators, each modulating a different color, and chromatic aberration is compensated by electronically scaling or shifting images from different image modulators differently.

Abstract: A 4-prism color management device (600) comprised of first, second, third, and fourth prisms (610, 612, 614, 616). The first prism (610) is adjacent to the second prism (612) with an air gap (620) interposed therebetween, the second prism (612) is adjacent to the third prism (614) with an air gap (624) interposed therebetween, and the third (614) prism is adjacent to the fourth prism (616) with an air gap (626) interposed therebetween. The first prism (610) includes a first surface (630) for inputting and outputting a beam of light. The second prism (612) includes a first dichroic surface (642) mounted at a first angle (&bgr;) with respect to the first surface (630) for reflecting light of a first color and for transmitting light of a second color and light of a third color. The third prism (614) includes a second dichroic surface (644) mounted at a second angle (&khgr;) with respect to the first surface (630) for reflecting light of the second color and for transmitting light of the third color.

Abstract: An optical wedge compensates for a vertically drifting laser beam in response to ambient temperature fluctuations. A slit sensor is formed onto a surface of the wedge to separate a single light pulse from a plurality of light pulses. A reflective filter layer is applied to a side opposite the slit sensor so an incident laser beam is attenuated thereby precluding damage to the slit sensor. The reflective filter coating further filters out unwanted light energy. The wedge is shaped so as to maintain a position of a focal point of a laser beam on the slit sensor and to prevent reflected light from damaging a laser source.

Abstract: An observation system having a positive refracting power as a whole comprises a first unit G1 with a positive refracting power and a second unit G2 and forms an exit pupil for observation of an electronic image displayed on an image display element 5. The first unit G1 comprises a prism 4 with a positive refracting power and a transmission-type volume hologram 6 and has an action of imaging an observation image for obtaining a relay image. The second unit G2 is composed of a reflection-type volume hologram 3 and has an action of forming the exit pupil 1 so as to introduce the relay image to an observer. At least one of reflecting surfaces and an exit surface of the prism 4 is shaped as a rotationally asymmetric surface which exerts a power on bundles of rays, to compensate aberrations generated by decentering.

Abstract: An optical system comprises, in succession from the object side, a first optical element of negative optical power, a second optical element of positive optical power, and a third optical element of negative optical power, at least one of the first to third optical elements being a refracting optical element having a reflecting curved surface.

Abstract: The invention provides a numerical aperture limiter for an optical thermal imaging system, comprising at least one pair of wedge-like prisms made of a transparent material having a known index of refraction, the prisms of the pair being disposed in close mutual proximity and in opposite orientation with the narrow end of one prism adjacent to the wide end of the other prism, the prism surfaces facing one another of the pair of prisms being spaced apart from one another by a distance at least equal to the wavelength of the light used by the imaging system, with the vertex angle of each one of the prisms being a function of the desired numerical aperture and the index of refraction.

Abstract: Prism elements having TIR surfaces placed in close proximity to the active area of a SLM device 302 to separate unwanted off-state 324 and/or flat-state 326 light from the projection ON-light bundle 322. The TIR critical angle of these prisms is selected to affect either the off-state light or additionally, any portion of flat-state light reflected from the SLM. These TIR surfaces are placed to immediately reflect the unwanted light as it comes off the SLM, thereby preventing the contamination of light along the projection path, which tends to degrade the system contrast. To further improve the optical performance of the system, these TIR prisms can be attached directly to the SLM package 300, completely eliminating the package window.

Abstract: Disclosed is an optical component, which comprises a prism element adjacent to a lens element, where the two elements are separated by a small air gap. In disclosed embodiments, the elements have adjacent and parallel surfaces which are substantially planar and which, with the small air gap, operate through Total Internal Reflection (“TIR”) to direct light beams that strike the planar surfaces. Light beams that strike at less than the critical angle are internally reflected, while light beams which strike at greater than the critical angle pass through. The TIR surfaces thereby separate the desired optical signals from the spurious ones. The combined TIR prism lens operates as a single and integrated component which directs desired light beams to a reflective optical processing element such as a Spatial Light Modulator and which focuses the processed light beams as they leave the combined TIR prism lens.

Abstract: The present invention comprises of a circular prism having beveled periphery and center faces cooperating with multiple other prisms to form a light capacitor. The present invention allows a user to collect and hold the light in a storage-type device for use in a concentrated way when desired.

Abstract: A prism unit, which is capable of firmly fixing a plurality of prism parts in a small space, and a laser device, which is capable of enhancing output power of laser light with use of the prism unit, are provided. For this purpose, a prism unit (28) includes a plurality of prism parts (35), which refract incident light (21), and a fixed part (36) which is fixed to or formed integrally with at least two of the plurality of prism parts. Further, a laser device includes the prism unit (28), and only a wavelength in a desired range out of a plurality of oscillation wavelengths is selectively oscillated by the prism unit.

Abstract: A beam shaping optical system which is provided with a first wedge prism having two refractive surfaces defining a first principal section, and a second wedge prism having two refractive surfaces defining a second principal section that is parallel to the first principal section, wherein a reference ray of light forms incident angles at each of the refractive surfaces of the prisms satisfying the following condition (1): &LeftBracketingBar; ∑ j = 1 L ⁢ α j &RightBracketingBar; < 0.020 .

Abstract: In an optical sheet 10 having a prism surface 16 formed by providing unit prisms 14 on the upper surface of a transparent base material 12, a coating layer 18 is provided on the reverse surface of the transparent base material opposite to the prism surface 16, spherical beads 20 are arranged projecting from the surface of the coating layer 18 by 1 to 10 &mgr;m in height, and the coating layer 18 is brought into contact with the flat and smooth surface 22A of the light-transmissive material 22 through the spherical beads 20 which are put between them. The spherical beads are 1 &mgr;m or less in half bandwidth of the distribution of particle diameters and are made uniform in height projecting from the coating layer 18.

Abstract: An optical coupler comprises a fiber optic prism (FOP) comprising first, second, and third side surfaces, the FOP being adapted to receive light through the first side surface, reflect the received light from the third side surface, and transmit the reflected light through the second side surface. The FOP may be used in an optical coupling arrangement comprising a substrate including a light element and a wave guide overlying the substrate, with the optical being situated such that one of the first and second side surfaces is adjacent the light element and the other of the first and second side surfaces is adjacent the wave guide.

Abstract: An achromatic beam shaping prism is disclosed which compensates for a fluctuation in oscillating wavelength of a semiconductor laser source of a recording type optical disc system using a single prism having a diffraction grating with a specified pitch so as to make the beam shaping prism achromatic. Two equations are given for specifying the pitch d or d′ of the diffraction grating, depending on whether the diffraction grating is applied to the output surface or the input surface of the prism, respectively.

Abstract: An optical path splitting element for splitting a light beam from a single object into at least two optical paths is made compact in size by using a three-dimensional optical system and given a power to reduce the number of components thereof. An image display apparatus uses the optical path splitting element. The optical path splitting element has a prism member having an entrance surface through which the light beam from the object enters the prism member, at least one reflecting surface reflecting the light beam within the prism member, and an exit surface through which the light beam exits the prism member. The prism member has at least one rotationally asymmetric surface. At least one optical functional surface is a discontinuous surface formed from at least two surfaces adjacent to each other. The other optical functional surfaces are common to the at least two optical paths.

Abstract: An optical sheet to be used for a back light unit of a liquid crystal display having at least a lamp and a light guiding plate has the following structure. The optical sheet is constituted by a lower base portion and an upper fitting portion which are fitted each other in a vertical direction with less margin, and the base portion and the fitting portion are formed of materials having different refractive indices. The base portion is provided with a large number of triangular portions having a triangular sectional shape in parallel, the triangular portion having a first side surface positioned on the left side and a second side surface positioned on the right side. Moreover, the first side surface of the triangular portion has an angle which is equal to or greater than an angle formed between a direction taking a peak of a ray refracted and incident on an inside of the base portion through a light guiding plate and the transverse direction.