Abstract: A polarization splitting grating coupler (PSGC) connects an optical signal from an optical element, such as a fiber, to an optoelectronic integrated circuit. The PSGC separates a received optical signal into two orthogonal polarizations and directs the two polarizations to separate waveguides on an integrated circuit. Each of the two separated polarizations can then be processed, as needed for a particular application, by the integrated circuit. A PSGC can also operate in the reverse direction, and couple two optical signals from an integrated circuit to two respective orthogonal polarizations of one optical output signal sent off chip to an optical fiber.

Abstract: When a video signal is inputted to a projector (10) through a video input terminal, a luminance peak value of an image of the video signal is detected by an image-analyzing circuit (61) to be outputted to a CPU (71). A gain-adjusting circuit (63) adjusts a luminance signal in the video signal based on a command from the CPU (71). The CPU (71) determines a gain adjustment amount based on the luminance peak value of the image obtained by the image-analyzing circuit (61) and outputs the result to the gain-adjusting circuit (63). For instance, when the luminance peak value (Ip) of the image is 50% of the upper limit (Imax) thereof, a gain-adjusting amount AG is doubled. In this case, an illuminating light volume of a light valve (44a) has to be reduced to 50%, which is achieved by light-attenuation by a light-source lamp (21) and an open/close light shield (23).

Abstract: A Mireau interference microscope is corrected for spherical and other aberrations induced by the beamsplitter and mirror support windows by incorporating a cover glass correcting-objective lens. The support windows for the beamsplitter and mirror have a combined thickness within the adjustment range of the cover glass correcting-objective lens.

Abstract: A projection system for presenting infrared scenes having biological and chemical agents, simulants and objects such as battlefield items. The generated scenes are primarily for the evaluation of infrared sensors, cameras and stand-off detectors. The system may have two or more projectors that combine various scenes into one scene having components with modified or imposed spectra signatures. Also, the system may generate a dynamic series of scenes that show synthetic scenarios of moving objects, agent clouds, non-toxic simulants and other items.

Abstract: A projection apparatus including a polarization conversion system to convert light having a first polarization component; a color recycling system, which separates the light into first and second color lights, to transmit and reflect the first and second color lights; an image forming system including a first reflective panel and a second reflective panel, which respectively modulate the first and second color lights, and a third reflective panel, which modulates the third color light; and an optical path conversion system, which splits the optical paths of fourth and fifth color lights incident from the color recycling system such that the first color light in the fourth color light is directed to the first reflective panel, the second color light in the fifth color light is directed to the second reflective panel, and the third color light in the fourth and fifth color light is directed to the third reflective panel.

Abstract: Accurate simulation of sport to quantify and train performance constructs by employing sensing electronics for determining, in essentially real time, the player's three dimensional positional changes in three or more degrees of freedom (three dimensions); and computer controlled sport specific cuing that evokes or prompts sport specific responses from the player that are measured to provide meaningful indicia of performance. The sport specific cuing is characterized as a virtual opponent that is responsive to, and interactive with, the player in real time. The virtual opponent continually delivers and/or responds to stimuli to create realistic movement challenges for the player.

Abstract: An optical pulse extender includes a delay loop formed by a plurality of mirrors and a graded reflectivity beamsplitter. The mirrors and the beamsplitter are configured and aligned such that a pulse to be broadened makes a predetermined number of round trips in the delay loop and is incident on a different zone of the beamsplitter after each round trip. The different zones of the beamsplitter have different reflection values and different transmission values. These values are selected such that the pulse extender delivers a plurality of temporally and spatially separated replica pulses each thereof having about the same energy. The delivered replica pulses together provide an extended pulse having a longer duration than the input pulse. The replica pulses may be passed through a beam homogenizer to spatially homogenize the temporal characteristics of the extended pulse.

Abstract: The present invention provides beam array controllers for changing the spatial and optical characteristics of a beam array. Beam array pitch controllers are provided which are capable of selectively adjusting the spacing between adjacent beams in a beam array. Beam array pitch controllers are provided which are capable of selectively adjusting the brightness and brightness spatial distribution of a beam array. The present invention also provides optical sources for generating a beam array having a selectively adjustable pitch, brightness and brightness spatial distribution.

Abstract: An imaging system includes a first off-axis illumination source for providing a first illumination field at a surface of an illumination modulator such that when the modulator is in a first non-activated mode a zero-order reflected illumination field is directed toward a first illumination blocking device, and when the modulator is in a second activated mode one first order reflected illumination field is directed toward an imaging surface while another first order reflected illumination field is directed toward a second illumination blocking device.

Abstract: Pathlength matched optical devices (such as beam splitters) are produced by viewing optical paths through the optical devices and adjusting relative positions of optical components of the optical devices until the viewed optical paths are equivalent. The optical paths begin at markings at different locations on the optical device. The optical pathlengths are equivalent when both markings are in focus in a limited field of view camera or lens. In a beam splitting cube constructed of two prisms, markings located at precisely similar locations on different prisms are pathlength matched when coincident as viewed at a reference face of the cube. The prisms are abutted at their diagonals and are adjusted by sliding the prisms along the diagonals to the pathlength matched position. Optical adhesive between the prisms is cured after fixing the prisms at the pathlength matched position.

Abstract: The present invention relates to a method and system for expanding a laser beam. An illumination system includes a horizontal reflective multiplexer and a vertical reflective multiplexer. The horizontal reflective multiplexer replicates the input beam along a first dimension to form a first multiplexed beam. The vertical reflective multiplexer replicates the first multiplexed beam along a second dimension to form a second multiplexed beam. In one example, the horizontal reflective multiplexer includes a first beam splitter, second beam splitter, and mirror. The vertical reflective multiplexer includes a beam splitter and mirror.

Abstract: A polarization splitting grating coupler (PSGC) connects an optical signal from an optical element, such as a fiber, to an optoelectronic integrated circuit. The PSGC separates a received optical signal into two orthogonal polarizations and directs the two polarizations to separate waveguides on an integrated circuit. Each of the two separated polarizations can then be processed, as needed for a particular application, by the integrated circuit. A PSGC can also operate in the reverse direction, and couple two optical signals from an integrated circuit to two respective orthogonal polarizations of one optical output signal sent off chip to an optical fiber.

Abstract: An image display device includes a case with an opening, a luminous source image display displaying a first image, and a focusing element. The focusing element is positioned within the case, and includes a concave mirror and a mirror supporter that supports the concave mirror. The mirror supporter includes a mirror cradle. The mirror screen is mounted on the arms of the mirror cradle. The mirror cradle includes a buffering pad at the tip of each arm, and the buffering pad includes adhesive parts on both surfaces. The tip of the arms of the mirror cradle is attached to the back of the mirror screen, and the attachment is achieved with a surface contact. The mounting holes on the top and bottom plates are oblong. The oblong mounting holes are adapted to adjust the mounting position of the mirror screen of the image display device.

Abstract: A color combining optical system which can suppress occurrence of a thermal problem and increase in size is disclosed. The color combining optical system comprises a first optical element which has a first optical film reflecting light having a first polarizing direction and transmitting light in a second polarizing direction and combines the first and second color lights by the first optical film. In addition, the optical system comprises a polarizing plate which analyzes a third color light. Furthermore, the optical system comprises a second optical element which combines, by a second optical film, the third color light transmitted through the polarizing plate with the first and second color lights combined by the first optical element.

Abstract: A display apparatus for vehicle that can use a space in an instrument panel effectively, minimize a display distortion and allow a vehicle driver to adjust a position of a visible range in an eye range comprises a display unit; a frame; a case; a supporting axis; and a retractable connecting member. The display unit includes a display device, an optical member for magnifying the image, a reflecting member for reflecting the image disposed in between the display device and the optical member, and a cover. The cover is attached to a frame fixed to an opening of the instrument panel for covering the opening. The display device, the optical member and the reflecting member are accommodated in the case integrally. The case is supported rotatably by the supporting axis inside the instrument panel. The retractable connecting member connects the case to the frame.

Abstract: A micromachined pellicle beam splitter and method of manufacture thereof are disclosed. In one embodiment, the beam splitter includes a silicon frame with a silicon nitride membrane attached to the frame and covering an opening through the frame. Other materials may be utilized, however, the coefficient of thermal expansion (CTE) of the membrane should be greater than that of the frame. The beam splitter may be manufactured by coating a silicon substrate with a layer of silicon nitride, patterning an opposite side of the silicon substrate with a photoresist or a metallic layer to define an opening an etching an opening through the substrate to the silicon nitride with either a dry etch or wet etch technique. An improved tunable laser module incorporating the micromachined pellicle beam splitter and a method of tuning a laser diode are also disclosed.

Abstract: An optical beam expander with a function of laser ray power detection provides an electric signal for feedback controlling laser ray power. By testing the power stability within a temperature range of 15 to 25° C., this apparatus demonstrates that it can stabilize an unstable laser to stable range of 5% when combined with a traditional self-controlling circuit arrangement.

Abstract: A beam splitter is constructed from three light transmissive members formed of a glass or plastic that are bonded together to form a rectangular parallelepiped when taken as a whole. First and second light separating surfaces are formed at the bonding surfaces of the first and second light transmissive members and the bonding surfaces of the second and third light transmissive members, respectively. Accordingly, three light beams can easily be formed from a single beam of incident light.

Abstract: A first optical system (11) has a first beam splitter (211). The first beam splitter (211) splits light arriving through a first optical path (P1) into two light beams, and outputs one light beam to a second optical path (P2) and the other light beam to a third optical path (P3). A second optical system (21) outputs the light output from the first beam splitter (221) to the second optical path (P2) and arriving at the second optical system (21) upon giving the light an intensity change with wavelength dependence and a phase change, and has a second beam splitter (221), first reflecting mirror (223), and second reflecting mirror (222). This makes it possible to provide an optical filter (200) which can realize a characteristic excellent in isolation with a very simple arrangement.

Abstract: A projector projects pixels to form an image in accordance with image data. The projector includes a modulator which modulates light from a light source and outputs projected pixels in a plurality of color spectral bands. The projector has a light source with a non-uniform spectral power distribution with spectral energy within each of the plurality of color spectral bands. A first notch filter removes spectral energy from a first spectral range within a first color spectral band to improve gamut.

Abstract: Device comprising: matrices of reflecting elements which can be electrically driven, and means for deconstructing a beam of polychromatic light and means for reconstructing complementary reflected beams, comprising two dichroic filters with a gradient where, for at least one of these filters, the direction of the gradient HOG, H?OG? makes an angle of inclination of non-zero gradient ?, ?? with a plane (DOE, D?OE?) orthogonal to the reflecting surfaces of the matrices. By virtue of the inclination of the gradient, the chromatic performance of the device is substantially improved.

Abstract: A low-voltage electromechanical device including a tiltable microplatform, method of tilting same and array of such devices are provided. The tiltable or steerable microplatform utilizes a bent-beam actuator to achieve large tilting angles with low actuation voltages. Thin beams of the actuator are bent in such a way as to cause the microplatform to pivot around a dimple support that generates a torsional force leading to angular motion in suspension beams attached perpendicular to the thin beams and, in turn, leading to angular or tilting motion in the suspended microplatform. Some of the key features include (1) the low-voltage bent-beam actuator; (2) a dimple-supported microplatform with a hole underneath in the substrate to allow light to pass through and to allow unhindered tilting of the microplatform; and (3) a method for constructing a microprism on the tiltable transparent microplatform for color dispersion purposes in an adaptive vision system.

Abstract: A light scanning unit having a simple structure and a low-priced multi-beam shape is provided. The light scanning unit includes a composite light source in which a plurality of light sources for emitting coherent light having different wavelengths are arranged adjacent to one another and an optical axis of each light source is arranged substantially parallel to each other and which emits light at a divergence angle centering on each optical axis. The plurality of coherent emitted light comprising a light beam. The light scanning unit further comprises a collimator lens which is arranged on an approximately central axis of the optical axis of each light source and collimates the light beam emitted from the composite light source, and a cylinder lens for condensing the light beam emitted from the collimator lens, a polygonal rotating mirror for scanning the light beam condensed by the cylinder lens in a main scanning direction on an exposed surface of an exposed object.

Abstract: An optical device having one or more optical components is disclosed. A waveguide extends from an optical component to a testing port configured to receive a light signal from a position over the optical device and to insert the light signal into the waveguide. In some instances, the testing port is configured to receive a light signal from the waveguide and to direct the light signal to a location over the optical device. The optical device can be positioned on a wafer before being separated from the wafer. The waveguide can extend from an optical component over the perimeter of the optical device such that the testing ports are located outside the perimeter of the optical device.

Abstract: Refracting optical system 1 and 2 relatively shift the second laser beam groups together with respect to the first laser beam groups along the layering direction. The transmission/reflecting optical system for alignment 1R, 2R, 1S and 2S are used, so that the laser beam patterns comprised of the first and second laser beam groups which are emitted from the transmission/reflecting optical systems 1R, 2R, 1S and 2S are shaped to be long in the layering direction of the laser bar, and since separate optical systems are used for shift and alignment, respectively, an individual optical system has a simple configuration.

Abstract: The invention provides a display-service providing system in which an image display apparatus, such as a projector, simultaneously displays a plurality of image data on a display section and the display sizes of the image data can be controlled. The invention provides such an image display apparatus. A display-service providing system is formed of instructing apparatuses to provide operation instructions to a projector serving as a service providing apparatus; a virtual-object management apparatus to control operations related to virtual objects, such as setting the virtual objects and giving the instructing apparatuses a right of instructing the projector; the projector to display images corresponding to the contents of instructions sent from the instructing apparatuses, on a display section; and a network to allow data communications to be performed between the above-mentioned apparatuses.

Abstract: A light consolidating system is provided for converging light emitted from at least one lamp positioned at the focus of an ellipse. A light guiding means is provided in the system for guiding the converged light to the output side. The system is characterized by the focusing feature of the ellipse lamps and therefore increases the efficiency of consolidating light.

Abstract: An optical system (10) comprises a camera (11) having an imaging means that in use faces downwardly, and an optical assembly. The optical assembly includes a support (14) that extends outwardly from the camera (11) and which has a lumen therethrough to allow transmission of light through the support (14) to the imaging means of the camera (11). The assembly further includes an optical unit (16) mountable to the support (14) and movable relative thereto towards and away from the imaging means of the camera (11). The optical unit (16) includes at least one lens (17) and a mirror assembly ( 22, 23) adapted to reflect at least some light entering the unit (16) that is at approximately a right angle to the orientation of the camera (11), through the lens (17) and into the lumen of the support (14) to the imaging means. The system (10) can be mounted to a headpiece worn by a user, such as a surgeon.

Abstract: The present invention relates to a color separating-combining optical system of a configuration having a separating optical system which separates light from a light source into a plurality of color spectrums; a combining optical system which combines light spectrums from a plurality of image display elements illuminated by the respective color spectrums; a filter which transmits a color spectrum of a specific wavelength band out of the plurality of color spectrums separated by the separating optical system; and a plurality of polarizing elements each disposed on the light entrance side of the plurality of image display elements, the polarizing elements being adapted to analyze the corresponding color spectrums incident to the respective image display elements. The color separating-combining optical system is further characterized in that the filter is placed apart from the polarizing element corresponding to the color spectrum transmitted by the filter.

Abstract: A display system is disclosed that includes a light source, an integrator rod receiving a light beam from the light source and producing an integrated light beam, a beam splitting device splitting the integrated light beam into at least a first cone of light and a second cone of light, the cones of light having complementary intensity distributions, and at least a first spatial light modulator and a second spatial light modulator, wherein the first spatial light modulator is capable of selectively reflecting portions of the first cone of light in an ON direction and the second spatial light modulator is capable of selectively reflecting portions of the second cone of light in an ON direction. The display system further includes a combining device for combining the selectively reflected portions of the cones of light in the ON direction and projection optics for projecting the combined reflected cones of light.

Abstract: A viewing optical system of an optical apparatus has an objective system for forming an image of an object and an eyepiece system for enlarging and directing the image to the pupil. The viewing optical system also has a hologram combiner comprising holograms of the volume type, phase type, and reflective type and having optical power for constructing a surface which is optically equivalent to the image surface at a different position than the image when viewed from the pupil. The system also includes an information display means for displaying information at the position of the equivalent surface, wherein the hologram combiner transmits light from the image and reflects light from the information display means so as to allow viewing of an image together with the information display overlaid onto the image.

Abstract: An apparatus is described for controlling the optical path length in an optical device, e.g. an interferometer, and more importantly to maintaining the optical path length difference in an interferometer. The apparatus may include an adjustable plate optically coupled with a beamsplitter. The plate may be rotated such that its surface receives light propagated from the beamsplitter at a non-zero incident angle. In one embodiment, temperature sensitivity is addressed by ensuring that the refractive index of the plate is greater than the refractive index of the beamsplitter. In another embodiment, the apparatus includes combination spacers having a component selected in dependence upon a composition, thickness, and orientation of the adjustable plate.

Abstract: A laser process system with multiple, independently steerable laser beamlets and including a laser and beam shaper for generating a shaped source beam, a splitter stage for generating a plurality of beamlets from the shaped source beam, a beamlet controller including an independently steerable beamlet steering mirror for and corresponding to each beamlet for independently directing the corresponding beamlet, a mirror controller for controlling each beamlet steering mirror, and an optical path including a scanning lens for directing each steered beamlet to a target area of a workpiece. Each beamlet steering mirror is a multi-axis micro-electro-mechanical mirror and the system further includes a beam dump located in the optical path for intercepting a beamlet steered into the beam dump by the corresponding beamlet steering mirror.

Abstract: A laser level includes a pair of level units arranged side by side and disposed in different oriented directions. Each laser level includes a laser light source adapted to emit a laser beam, a beam splitter adapted to simultaneously split the beam into first and second light beams along perpendicular first and second directions, and a first and a second aspheric-cylindrical lenses respectively arranged in the first and the second directions. The first and the second aspheric-cylindrical lenses have two optical axes respectively extending along the first and second directions.

Abstract: The small field-of-view (FOV) limitation of current coherent beam combiner technology is overcome, enabling beam combining over significantly larger fields of view. The system includes an input to receive an input wavefront, a local oscillator to generate a reference wavefront, and an optical combiner such as a beam splitter to combine the input wavefront and the reference wavefront to produce an output wavefront which is received by a detector. According to the invention, an optical element is supported to receive the reference wavefront and generate, in effect, a plurality of local oscillator point sources which provide a set of wavefronts that cover the required wider FOV. In the preferred embodiment, the optical element is a diffuser, and may optionally include a mechanism for rotating the diffuser to reduce speckle. In an alternative embodiment the optical element is a lenslet array.

Abstract: An optical arrangement is disclosed for obtaining information from a sample or an observed object which comprises a light source for illuminating the sample or observed object and a reception device for the light proceeding from the sample or observed object. At least one beam splitter is included having a splitter surface with a transmittive area and a reflective area. Light from the source is directed to the splitter surface, reflected by the reflective area of the splitter surface to a concave mirror, focused by the concave mirror onto the transmittive area and passes through the latter, or the light is focused onto the transmittive area, passes through the latter to a concave mirror, is directed from the concave mirror to the splitter surface and is deflected by the reflective area of the latter. The focusing is influenced by the geometry of the mirror surface of the concave mirror and the distance between the concave mirror and the splitter surface.

Abstract: An automated optical inspection system with improved accuracy achieved by reducing the negative effects of extraneous light. The system includes a light trap behind a two-way mirror.

Abstract: Accurate simulation of sport to quantify and train performance constructs by employing sensing electronics for determining, in essentially real time, the player's three dimensional positional changes in three or more degrees of freedom (three dimensions); and computer controlled sport specific cuing that evokes or prompts sport specific responses from the player that are measured to provide meaningful indicia of performance. The sport specific cuing is characterized as a virtual opponent that is responsive to, and interactive with, the player in real time. The virtual opponent continually delivers and/or responds to stimuli to create realistic movement challenges for the player.

Abstract: An optical device for processing radiation that includes a beam splitter and a plurality of radiation processing parts arranged to process the characteristics of different radiation components separately, The polarizing beam splitter includes a wire grid polarizer, a first transparent plate arranged adjacent one side of the polarizer and a second transparent plate arranged adjacent the other side. Each of the first and second plates have substantially equal optical thickness profile.

Abstract: The invention is an apparatus for lengthening the path of a light beam. The apparatus includes an at least partially enclosed chamber having a first opening and a second opening. A first reflective surface is disposed within the chamber and is obliquely oriented with respect to an incoming path of the beam. The beam reflects off of the first reflective surface after the beam enters the chamber through the first opening. Second and third reflective surfaces are disposed within the chamber and are generally parallel to the incoming path of the beam. The beam is reflected a plurality of times between the second and third reflective surfaces after the beam is reflected by the first reflective surface. A fourth reflective surface is disposed within the chamber and is obliquely oriented with respect to the incoming path of the beam. The fourth reflective surface directs the beam through the second opening after the beam has been reflected a plurality of times between the second and third reflective surfaces.

Abstract: A projection type image display apparatus comprises a light source unit; an integrator unit for mixing luminous fluxes emitted from the light source unit so as to homogenize their light quantity distribution; a curved mirror for bending the optical path of luminous fluxes, which are turned into uniform light by the integrator unit, toward a projection unit; and the projection unit for causing the luminous fluxes to carry image information and projecting these luminous fluxes onto a screen.

Abstract: An optical arrangement for directing illumination light to a sample and for directing the detection light proceeding from the sample to a detector has a spectrally selective influencing means in the beam path of the detection light, which influences the polarization properties of the illumination light reflected or scattered from the sample in such a way that a polarizing beam splitter splits the illumination light reflected or scattered from the sample out of the detection light.

Abstract: A micromachined pellicle beam splitter and method of manufacture thereof are disclosed. In one embodiment, the beam splitter includes a silicon frame with a silicon nitride membrane attached to the frame and covering an opening through the frame. Other materials may be utilized, however, the coefficient of thermal expansion (CTE) of the membrane should be greater than that of the frame. The beam splitter may be manufactured by coating a silicon substrate with a layer of silicon nitride, patterning an opposite side of the silicon substrate with a photoresist or a metallic layer to define an opening an etching an opening through the substrate to the silicon nitride with either a dry etch or wet etch technique. An improved tunable laser module incorporating the micromachined pellicle beam splitter and a method of tuning a laser diode are also disclosed.

Abstract: A three element prism system and method for splitting/combining three different colors of light arranged such that the size of a selected one of the color prism, such as for example, the red prism and, consequently the clear aperture, are increased without a corresponding increase in the size of the other prisms (e.g., the blue and green prisms). This is accomplished by adjusting the air gap A2 of the selected light path (e.g., red) so that the effective total selected light path T, which includes the selected light air gap A2 and the selected light glass path G2 is the same as the total path length T of both the other light paths (e.g., green and blue) comprised of air gap A1 plus glass path G1.

Abstract: A laser beam incident on a rod lens has a greater cross-sectional diameter than that of a rod lens main body, and mirrors are provided near the rod lens main body to reflect incident light toward the same. Since light of a strong beam intensity reflected onto the rod lens main body by the mirrors produces a greater angle than light of weak beam intensity, this configuration has an effect of increasing the light intensity on the ends of a resulting line beam and, thus, expands the spreading angle of visible light in the line beam.

Abstract: A head-mounted display comprises monocular or binocular display chambers. Each display chamber is equipped with an optical engine that displays images. The mechanism of the optical engine is as follows: cast rays from a light source onto an LCoS device through a first polarizer, and an image is formed with rays, which reflect off the bottom of the LCoS device. The reflective rays penetrate the first polarizer and a film-coated beam splitter. With a concave mirror, the image is magnified and projected onto the surface of the beam splitter. Finally, the magnified image is formed in a viewer's eyeballs by means of the beam splitter.

Abstract: A projection display apparatus in which a light emitted from a reflective light valve is made incident on a prism member and a light having passed through the prism member is projected by a projection lens, comprises a dust proofing cover that provides a seal between an emergence surface of the reflective light valve and an incidence surface of the prism member.

Abstract: The light emitted from a warning display unit 16 is passed through a front glass 18 formed at the opening of a dash board 17 and a semi-permeable combiner 12 having a first polarizing plate 12b in this order so that it is guided to a driver's view point I. A second polarizing plate having the same polarizing direction as that of the first polarizing plate 12b is formed on the surface of the front glass 18. In this configuration, the wash-out in the warning display unit, i.e. a light emitting source, arranged behind a combiner can be prevented and visual recognition of the light emitting source can be improved.

Abstract: A catadioptric objective is provided with a beam splitter surrounded at least partially by a mount, with a mirror, with a plurality of lenses and with a &lgr;/4 plate arranged between the mirror and the beam splitter.

Abstract: A microscope having at least one beam splitter in the microscope beam path and a scattered light reducing device comprises as the scattered light reducing device a black glass plate that has a polished surface on which an antireflection coating is applied. The black glass plate is preferably arranged behind the beam splitter at a slight inclination with respect to the direction of the incoming illumination beam, so that a residual reflection occurring at the black glass plate is reflected out of the microscope beam path by the beam splitter.