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: A method and apparatus for cleaning, detecting, and/or removing contamination from the surfaces of nominally transparent materials utilizing internal illumination of those surfaces with at least one electromagnetic radiation beam at an angle of incidence equal to or greater than the critical angle for total internal reflection. With appropriate selection of light sources and materials, the technique is effective at detecting and removing water, ice, particles, films and a variety of contaminants.

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: A color image display system and a color image pickup system adapted to electronically correct the color shift of color separation images caused by a decentered optical system used to display or capture a color image. The color image display system has an image display apparatus including a color image display device for displaying a color image composed of color separation images superimposed on one another. The displayed color image is projected into an eyeball of an observer through a viewing optical system that is formed from a decentered optical system including a decentered prism having at least a decentered internally reflecting surface with a power, together with an entrance surface and an exit surface, which are transmitting surfaces. The pixel position of each color separation image to be displayed on the color image display device is shifted so as to cancel a color shift of the corresponding color separation image caused by the decentered optical system.

Abstract: A TIR prism for use in projection displays, which enables angular separation of input illumination and projection light. By controlling the critical angle of a TIR surface, a portion of the illumination cone can be made to fail TIR, thereby being removed from the system prior to overlapping the projected light and lowering the image contrast. Since this truncation of the illumination aperture is translated proportionally across all optical apertures, the input aperture can be increased to overcome the loss of image brightness due to removing this portion of the illumination. In addition, other TIR surfaces are incorporated to remove unwanted diffracted light from OFF-pixels and flat-surfaces soon after this light enters the prism, preventing it from scattering into the desired projected light path from the ON-state pixels.

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 multilayer ceramic substrate 11 is used, and a prism 14 serving as a component of a hybrid optical module and a chip 12 on which an optoelectric converting element is mounted are mounted on different layers of the multilayer ceramic substrate. The thickness of the chip on which the optoelectric converting element is mounted is substantially equal to the depth of the layer of the multilayer ceramic substrate on which the chip is mounted.

Abstract: In a vehicle periphery visual confirmation apparatus, between the vertical angle portion 5 of a prism 4 and the front end portion 28 of a case 3A is interposed a light shield portion 3a which shields light rays crossing substantially in the right and left direction in front of the prism 4. Even in case where light rays coming from the outside enter in front of the vertical angle portion 5 of the prism 4 and are going to cross in front of the prism 4, the light rays can be prevented by the light shield portion 3a. This can prevent the overlapped reflection of a vision image resulting from the fact that the light rays crossing in front of the prism are reflected by the internal surfaces of the penetration window portions and enter the interior portion of the prism.

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: The invention relates to a device for scanning an object using a scanning beam which is directed into a rotating deflector and which is diverted onto the object at a controllable diversion angle using a diverting unit that is arranged in a moveable manner. The diversion angle of the diverting unit is adjusted according to the centrifugal force acting upon said diverting unit and according to the rotational speed of the deflector.

Abstract: A prism (1) has a first inner surface (114A) and a second inner surface (122) in its interior. The first inner surface (114A) performs total reflection of all rays (20) entering from the exterior, and is disposed apart from a variable mirror element (3) disposed in the exterior, such that the reflected rays are irradiated to the variable mirror element (3). The second inner surface (122) is disposed in proximity to the variable mirror element (3), and totally reflects a bundle of OFF rays from the variable mirror element (3), while allowing a bundle of ON rays from the variable mirror element (3) to pass therethrough.

Abstract: A projector of the type which uses an optical modulator that modulates light by controlling the emitting direction of light applied to a light illumination surface in accordance with image information is provided with a reduction in size. In the projector a prism has a selective reflection/transmission surface which reflects illumination light emitted from an illumination optical system and impinging thereupon, and causes the illumination light to impinge upon the light illumination surface of an optical modulator at a predetermined angle. The prism allows the modulated light emitted from the optical modulator to be transmitted therethrough and emits the light to the projection optical system.

Abstract: An optical element having a complex structure of diffraction grating, an inclined surface, a difference in level and the like and of good optical characteristics, its manufacturing method, and an optical element manufacturing metal die capable of injection molding the optical element are disclosed. By using an optical element manufacturing metal die constituted to have nestings which have mirror surface forming portions two adjoining pairs of mirror surfaces of the optical element are molded by two adjoining pairs of mirror surface forming portions which are formed on the same nesting. The optical element manufacturing metal die is constituted to include the nesting having a diffraction grating forming portion in which a predetermined concave-convex pattern for molding the diffraction grating of the optical element is formed on one surface of a substrate.

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 enhanced illumination system for a micro-display comprises an illuminator for a reflective display panel having a light source and a prism. The prism has a first substantially planar face proximate to the light source and to the display panel, so that light propagates from the light source into the prism through the first face and is redirected to the display panel through the first face. A second face of the prism is positioned opposite the light source so that light reflected from the display panel impinges on the second face and propagates to imaging optics. The illuminator may also include an auxiliary prism optically coupled to the second face of the first prism to correct for astigmatism of the reflected light from the display panel and a beam splitter between the first prism and the auxiliary prism.

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: A beam splitter has a support frame made of silicon that has a membrane inside made of silicon. The membrane has in particular openings with bridges formed between them. On the side of membrane facing the incident beam is an aluminum coating to increase the reflectability or degree of reflection of the membrane. An incident beam bundle contacts the beam splitter at angle of incidence &phgr;. A portion of the incident beam is reflected off the bridges, and the remaining portion of the beam freely passes through the openings. The beam is correspondingly divided into a reflective portion and transmitted portion.

Abstract: A viewing optical system for display apparatus allows observation of a bright displayed image favorably corrected for aberrations and is easy to assemble, resistant to impact such as vibration, lightweight and compact. An ocular optical member for leading an observation image formed by an observation image forming member to an exit pupil has a first prism member and a second prism member. The first prism member has a first entrance surface, a reflecting surface and a first exit surface disposed to face each other across a first prism medium. The second prism member has a second entrance surface and a second exit surface disposed to face each other across a second prism medium. The first and second prism members are cemented together with a holographic element interposed between the first exit surface and the second entrance surface. The reflecting surface has a positive power. The first exit surface and the second entrance surface are each formed from a plane or cylindrical surface.

Abstract: An optical film for use in transparent displays, such as reflective LCDs. The optical film has three-dimensional, prismatic structures that reflect incoming light. The prismatic structures are elongate structures configured so that the reflecting facets orient the reflected light in desired reflective light pattern. The pattern shape and intensity can be controlled by the shape and dimensions of the various reflecting facets. In one embodiment, the height of the prismatic structure varies along the elongate structure.

Abstract: A first surface of an optical component has a lens function of converging the transmission light from a light source. A second surface reflects the transmission light, converged by the lens function of the first surface, towards an end face of an optical transmission medium as the destination of transmission. The light reflected by the second surface is radaited from a coupling surface. Since the light beam from the light source is directed towards the optical transmission medium by exploiting the total reflection of light, a high-reflection multi-layer film or a polarization beam splitter film, required in a conventional apparatus employing a polarization beam splitter, is unneeded, with the result that the film forming cost or the cost in bonding two prisms used for fabricating the polarization beam splitter may be dispensed with. In this manner, the production cost or size of the apparatus can be reduced without lowering the transmission/reception performance.

Abstract: A color-separating prism for producing narrow-spectral light from broader spectral light includes first, second, and third component prisms that form first and second adjacent pairs of faces. The color-separating prism also includes first and second reflective layers disposed between the prisms. The first and second reflective layers each reflect separate portions of input light back toward the front surface. In operation, a first portion of a light beam in a first wavelength range is reflected from the first reflective layer back toward the front face of the prism, and a second portion of the light beam in a second wavelength range is reflected from the second reflective layer back toward the front face of the prism. The first and second portions are totally internally reflected from the front face and exit the color-separating prism. The color-separating prism can be used in display systems.

Abstract: A prism includes: a first portion made of a first material having a wavelength dependency in a refractive index; and a second portion adhered to the first portion, the second portion being made of a second material having a wavelength dependency in a refractive index which is different from the wavelength dependency in the refractive index of the first material. The first portion and the second portion have shapes such that the wavelength dependency in the refractive index of the first portion and the wavelength dependency in the refractive index of the second portion are substantially cancelled by each other.

Abstract: An optical device (29) for rotating the polarization of a linearly polarized, broadband input beam of light (3) comprises prism means (30, 37, 43). The input beam is incident normal to a first face (31) and exits normal to a second face (47) of the prism means. The prism means comprises a light transmitting material having a plurality of totally internally reflecting surfaces (32,33,34) and one or more interfaces, the totally internally reflecting surfaces are arranged such that the polarization of the exit beam is rotated by 90° relative to the input beam, each interface comprises a pair of parallel surfaces (35, 39) separated by a gap (36), the parallel surfaces are arranged substantially to satisfy the Brewster condition such that surface reflection losses are minimized and the input and exit beams are substantially collinear.

Abstract: There is disclosed an optical system for light beam amassment and concentration derived through intensification by cyclical accretion of light energy by passing a parallel light beam perpendicular to a 100% reflection double-faced conical optical glass prism repetitively cyclically via plural 100% reflective single-faced right-angle isosceles optical prisms arranged in a path surrounding said compound optical glass prism defining an endless recycled return path to and through said compound optical glass prism, the amassment occurring during the passage of said light beam through said compound conical prism to be reflected from the conical prism as an emergent amassed and concentrated light beam occasioned by each repeated pass to and from said conical portion of said compound prism and to and through a beam-splitting quadrivial prism to said return path to said compound prism and the conical prism portion thereof and emergence therefrom, an single-faced right-angle isosceles prism arranged to intercept said e

Abstract: A see-through retroreflective structure includes a transparent polymeric film, an array of retroreflective elements attached to the polymeric film, and an array of apertures through the retroreflective structure within the array of retroreflective elements. In one embodiment, the retroreflective structure includes a metalized reflective layer formed on the transparent prism elements and a support layer, such as a fabric, is attached to the metalized reflective layer. The method includes providing a transparent polymeric film. An array of retroreflective elements is attached to the polymeric film. The array of retroreflective elements and the transparent polymeric film are perforated through the retroreflective structure to form an array of apertures, thereby forming a retroreflective structure. The apertures are of sufficient size and spacing to provide a see-through capability.

Abstract: In order to provide a grism wherein even if the vertex angle of a prism increases, it does not exceed its critical angle, besides, which can elevate its efficiency, and mass-production of which is possible, whereby reduction in cost of which can be realized. The grism comprises a first prism having a high refractive index, a second prism having a high refractive index, and a volume phase grating used for a diffraction grating; and the vertex angle of the first prism being opposed to the vertex angle of the second prism so as to sandwich the volume phase grating between the first prism and the second prism.

Abstract: A light deflector/recombiner is longitudinally symmetrical with respect to an X axis perpendicular to a Z axis. An X and Z vector components inverter longitudinally symmetrical with respect to both the X axis and a Y axis perpendicular to the X and Z axes lies parallel to the deflector/recombiner. A Y vector component inverter longitudinally symmetrical with respect to the X axis lies parallel to and between the deflector/recombiner and the X and Z inverter. The Y inverter has many reflector elements. Light rays incident in the Z direction encounter an element only once during return passage between the deflector/recombiner and the X and Z inverter. The X and Z inverter directionally inverts the rays with respect to the X and Z axes and the reflector element directionally inverts them with respect to the Y axis, such that substantially all incident rays are retro-reflected with respect to the X, Y and Z axes.

Abstract: A first surface of an optical component has a lens function of converging the transmission light from a light source. A second surface reflects the transmission light, converged by the lens function of the first surface, towards an end face of an optical transmission medium as the destination of transmission. The light reflected by the second surface is radaited from a coupling surface. Since the light beam from the light source is directed towards the optical transmission medium by exploiting the total reflection of light, a high-reflection multi-layer film or a polarization beam splitter film, required in a conventional apparatus employing a polarization beam splitter, is unneeded, with the result that the film forming cost or the cost in bonding two prisms used for fabricating the polarization beam splitter may be dispensed with. In this manner, the production cost or size of the apparatus can be reduced without lowering the transmission/reception performance.

Abstract: A semiconductor device lead inspection apparatus and method are provided for capturing images of the semiconductor edges and leads along two optical axes which have different directions in a plane perpendicular to the semiconductor device edge. A first image is reflected off an optical surface of a prism to a direction corresponding to the camera optical axis. A second image is reflected by two optical surfaces of the prism to a direction corresponding to the camera optical axis.

Abstract: A first surface of an optical component has a lens function of converging the transmission light from a light source. A second surface reflects the transmission light, converged by the lens: function of the first surface, towards an end face of an optical transmission medium as the destination of transmission. The light reflected by the second surface is radaited from a coupling surface. Since the light beam from the light source is directed towards the optical transmission medium by exploiting the total reflection of light, a high-reflection multi-layer film or a polarization beam splitter film, required in a conventional apparatus employing a polarization beam splitter, is unneeded, with the result that the film forming cost or the cost in bonding two prisms used for fabricating the polarization beam splitter may be dispensed with. In this manner, the production cost or size of the apparatus can be reduced withut lowering the transmission/reception performance.

Abstract: A low profile rearview mirror for a motor vehicle having a first refractor with a first refractive index and a first chromatic dispersive poser. The first refractor is disposed in a housing on the exterior of the vehicle A reflector mounted partially within the motor vehicle extends into the housing for the first refractor and the retractor is positioned to receive and reflect light from objects behind the vehicle passing through the first refractor. A second refractor having a second refractive index and a second chromatic dispersive power is mounted between the first refractor and the reflector and the first and second refractors have complementary properties of chromatic dispersion.

Abstract: A display system has a directional reflection screen with a triangularly-shaped mirror sheet as horizontal focusing for observers and stereoscopic image projecting means. The directional reflection screen has a triangularly-shaped mirror sheet with included angles at least some of which are non-right angles. This enables a plurality of observers to simultaneously obtain a stereoscopic view using a binocular parallax without wearing special glasses and without having to position themselves in a very limited number of positions relative to the screen. Vertical diffusion can also be provided by using a lens sheet. The screen can be made concave in the horizontal or vertical directions, or both.

Abstract: A method of making a micro magneto-controlled optical path-guiding platform comprises an optical path-guiding platform, couples of the optical routes, a micro magneto-flux prism located at the intersection of the optical route on the topside of the platform, and a magnetic field generator oppositely mounted under the location of the micro magneto-flux prism of the platform bottom side respectively. Therefore, the reflection ratio and refraction ratio to the incident optical signal traveling through this designed micro magneto-flux prism will be completely manipulated by adjusting the magnetic field intensity that is generated by the magnetic generator. Conclusively, this invention can be used to change the traveling orientation of the optical route or control the optical energy intensity as desired.

Abstract: An optical device for eliminating the stray light is provided at a stop of an illuminating system in an optical system of “digital light processing” (DLP). The optical system consists of a stop of an illuminating system, a “digital micromirror device” (DMD), a stop of a projection lens, and a screen while the stray light is a chromatic halo at the peripheral area on the screen. Wherein, the optical device includes a reflecting mirror designed of an adjustable angle and installed near periphery of the stop of the illuminating system. The chromatic halo is generated from the light beam at the periphery area. And, the light beam is reflected from the DMD and is transmitted into the stop of the projection lens, and then is projected on the screen.

Abstract: One embodiment of the present invention is an optical path length scanner which includes: (a) a set of prisms mounted evenly along a movable carrier; and (b) a mechanism that drives the movable carrier to move.

Abstract: A projection type display device constructed so that light source beams via a polarization beam splitter are separated of colors by a color separating/synthesizing optical system and enter light valves disposed for every color light, the light beams exiting from the respective light valves are synthesized by the color separating/synthesizing optical system, the synthesized light beams exit, the polarization beam splitter analyzes the synthesized light beams and takes out the analyzed light beams, and the analyzed light beams are projected on a screen through a projection lens. A normal line of an outgoing surface of the polarization beam splitter with respect to the light source beams exiting toward the color separating/synthesizing optical system from the polarization beam splitter, has a predetermined angle larger than zero degree with respect to an optical axis of the light source beams.

Abstract: An optical device has a mount including a mount surface with a longitudinal axis. A diode source has a first diode emitter producing a first beam, a second diode emitter producing a second beam and a third diode emitter producing a third beam. The diode source is mounted above the mount surface at an angle &thgr; relative to the longitudinal axis of the mount. A prism array has a first prism face, a second prism face and a third prism face. The prism array has an angled surface cut at the angle &thgr; relative to a longitudinal axis of the prism array. The first, second and third beams are incident on the first, second and third prism faces respectively. Optical path lengths between the first, second and third diode emitters relative to the first, second and third prism faces are equal.

Abstract: The object of the invention is to make a viewing unit of the image display compact so that it can be mounted on portable telephones or information terminals. The portable image display of the invention comprises a speaker portion, a microphone portion, an image display device 9 and a viewing optical system for forming an exit pupil to view an image displayed on the image display device and having a generally positive refracting power. The viewing optical system is constructed of at least one prism member 10 comprising an entrance surface through which a light beam emanating from the image display device 9 is entered into the prism, at least one reflecting surface at which the light beam is reflected within the prism and an exit surface through which the light beam leaves the prism. The at least one reflecting surface has a curved surface shape for imparting power to a light beam.

Abstract: A red-reflecting film and a blue-reflecting film are formed in a substantially X shape on joint surfaces defined by the respective side faces of four columnar prisms or right-angle prisms. The red-reflecting film is continuously formed without separating at an intersection of the two reflecting films. The blue-reflecting film is, on the other hand, divided into two pieces by the red-reflecting film and an adhesive. It is preferable that that four columnar prisms are obtained from one block of sheet glass. This arrangement ensures an improvement in properties of a resulting light-selective prism.

Abstract: In a cross dichroic prism wherein four square pillar prisms of which the total of the angles including the prism ridge lines is 360° are joined together with the prism ridge lines thereof made coincident with one another and prism sides forming the respective prism ridge lines are joined together so that the joined surface thereof may become two planes intersecting with each other, and dichroic film is provided on the joined surface, when the lengths of perpendiculars from a point on the prism ridge line to the non-joined surfaces of the respective square pillar prisms are defined as L1, L2, L3 and L4, L1≠L2=L3=L4 is satisfied.

Abstract: A method for installing an electro-optical device to a prism and a manufacturing method for a projector that permit improved positional accuracy, improved fixing operation efficiency, and a simplified fixing operation process of an electro-optical device are provided. The methods are provided with spacer mounting process steps for mounting a spacer via an adhesive agent between a panel frame assembly, which holds an electro-optical device, and a prism, position adjusting process steps for adjusting a position where the panel frame assembly is installed to the prism after the spacer mounting process steps, and panel frame assembly fixing process steps for fixing the panel frame assembly by hardening the adhesive agent after the position adjusting process steps.

Abstract: Disclosed is a prism having a light incident surface, a light emerging surface, and at least one light reflection surface. The light incident on the light incident surface is reflected, inside the prism, by the light reflection surface, and emerged from the light emerging surface. At least one light reflection surface has a reflecting surface which does not satisfy a total reflection condition. A reflection area is formed on the at-least-one light reflection surface by applying light reflecting material. The reflection-area corresponds to a portion on which a normal light is incident. Further, a portion of the-at least-one reflection surface other than the reflection area is formed to be a low-reflection area-which has a lower reflectance index than the reflection area.

Abstract: A configuration of prisms is capable of spectral division, or spectral color combination, or both simultaneously even with reflected light that undergoes a change of polarization. The configuration includes first and second prisms each with pairs of faces that respectively form first and second prism angles. One face of one prism is engaged against one face of the other prism with no air gap between. Light of a first spectral range is incidence substantially perpendicular on the other prism face of the first prism after entering the first prism and undergoing a double reflection before leaving the first prism. Light of a second and third spectral range are also incident on the other face of the first prism and pass substantially unreflected through the first prism. Light of the second spectral range after leaving the first prism and entering the second prism is double reflected in the second prism. Light of the third spectral range substantially passes through the second prism as well without reflection.

Abstract: An optical system and, more specifically, an image pick-up optical system having a small size and satisfactory aberration, in which an optical system includes an optical unit having a light incident surface on which light is incident, a light reflecting surface having a curvature to reflect the light incident from the light incident surface, and a light exit surface from which the light reflected by the light reflecting surface emerges, and has a refractive index distribution, is disclosed.

Abstract: An optical scanner including a scanner head, a roller engaged by a record, the roller including optically readable marks, light sources and sensor which illuminate and sense both roller and the record, a lens for focusing light from the record onto the sensor, and a lens mirror for focusing light from the roller onto the sensor.

Abstract: A composite optical device comprises an optical element bonded onto a support body with an adhesive, at least a part of surfaces of the optical element being covered by a film made of a hydrophilic material. A method for manufacturing a composite optical device having an optical element bonded onto a support body with an adhesive, comprises the steps of: preparing a bar-shaped optical element having a length not less than twice the width thereof and having surfaces at least a part of which is covered by a film made of a hydrophilic material, and bonding the bar-shaped optical element on the support body with the adhesive; and cutting the bar-shaped optical element, the adhesive and the support body while applying a liquid containing water at least to portions where they are cut.

Abstract: An optical unit for projecting an image including first and second locating lines for substantially eliminating the introduction of visual parallax error. In one preferred form, the optical unit is incorporated into a machine for performing a forming operation on a workpiece and is operative to project an image of a portion of a scale to a position easily read by the user during machine operation. The optical unit includes a prism portion having a first side disposed adjacent the scale, a second side at an angle to the first side for reflecting the image and a third side through which the projected image may be viewed. The first locating line is disposed on the first side and the second locating line is disposed on the third side such that visual alignment eliminates the introduction of visual parallax error associated with reading a scale.

Abstract: A heat-treatable dichroic mirror, comprising a transparent substrate having a glass transition temperature in the range of 650-800° C., and a plurality of sputtered films carried on said substrate and forming at least two pairs of contiguous films in which the films of each pair have disparate refractive indices differing by at least about 0.2 so as to provide between them a reflective interface. The films include an oxide of a metal such as titanium, a second film comprising an oxidizable metal or semi-metal such as silicon, and a protective overcoat of a thickness and composition sufficient to substantially prevent permeation of oxygen therethrough when heat treated at said glass transition temperature. The mirror, after said heat treatment, exhibits a transmittance of at least 24% in the wavelength range of 550-650 nm, a reflectance of at least 45%, and a haze of not greater than about 1%.

Abstract: A fingerprint imaging system includes a light source, an optical platen having a light receiving face positioned such that the light from the source impinges thereon, and a finger receiving face positioned such that light from the light source through the light receiving face impinges on the finger receiving face. A light detector is positioned to receive light from the light source reflected from the finger receiving face. The light receiving surface of the platen is configured to avoid reflection of external light passing through the finger receiving face and impinging on the light receiving face.

Abstract: Polarization preserving optical systems for use in deviating plane polarized beams through preselected angles without changing their linear state of polarization. The optical systems have a variety of applications and are particularly suitable for use in the field of distance measuring interferometry (DMI) to enhance measurement accuracy by reducing undesirable polarization effects that can introduce errors associated with an otherwise present undesirable polarization rotation found in classical retroreflectors. Prismatic optical elements are preferably used to construct assemblies which can include polarization beam splitting coating arrangements and/or birefringent materials to enhance the extinction ratio between orthogonally polarized beams propagating through such systems.