727 results about "Oblique angle" patented technology

An optical inspection system for pre-bonding inspection includes a stage having a surface on which a sample to be inspected is placed, the surface of the sample having at least parts with a two dimensional (2D) periodic pattern which may include defects, an optical head including optics, a dark-field illuminator configured to illuminate the surface of the sample at an first angle, wherein the first angle is an oblique angle, a bright-field illuminator configured to illuminate the surface at a second angle, a dark-field collection path, a bright-field collection path, and a sensor configured to detect light transmitted from the dark-field illuminator, scattered at the surface of the sample, collected by the optical head, and relayed through the dark-field collection path, and light transmitted from the bright-field illuminator, reflected at the surface of the sample, and relayed through the bright-field collection path.

The invention relates to the technical field of tool control, in particular to a tooth cutting tool parameter control system based on bevel angle cutting, which comprises a tool parameter acquisition module used for acquiring the rotating speed, the axial feeding amount and the cutting depth of a tool in real time; the force-heat prediction model is used for outputting predicted cutting force and predicted cutting tool temperature; the multi-target parameter optimization model is used for receiving constraint conditions set by a user, optimizing the rotating speed, the axial feeding amount and the cutting depth of the cutter by taking the lowest cutting force, the lowest temperature of the cutting cutter and the highest machining efficiency as targets in the constraint conditions, and integrating and outputting a regulation and control strategy; and the cutter parameter control module is used for regulating and controlling the rotating speed, the axial feeding amount and the cutting depth of the cutter based on a regulation and control strategy when the predicted cutting force and the predicted temperature of the cutting cutter exceed threshold values. According to the method, by accurately regulating and controlling the parameters of the tooth cutting tool, the machining efficiency of the tooth cutting tool can be ensured, and meanwhile the abrasion speed of the tooth cutting tool is reduced.

A bolt locking type engineering cutter head belongs to the technical field of engineering machinery cutters and comprises a cutter head, a cutter holder, a cutter bar and a lock, the cutter head is mounted on the cutter holder, and the cutter bar penetrates into the cutter holder and is connected with the cutter head through the lock. An inner cavity is formed in the tool bit, a first inclined groove and a second inclined groove are formed in the two sides of the inner cavity respectively, and the bottom of the first inclined groove is downwards communicated with the bottom face of the tool bit. A mounting seat of the tool bit is sleeved in the circular groove, a core column is arranged in the center of the tool apron, the core column is sleeved in an inner cavity of the tool bit, a through square hole is formed in the center of the core column, a tool bar is inserted into the square hole, a through large transverse groove is transversely formed in the middle of the core column, and a lock head is arranged in the large transverse groove in a penetrating manner. The cutter bar comprises a bar body and a pin rod, and the bar body penetrates through the cutter holder from bottom to top. The lock head comprises a lock block and pins, the lock block is composed of a pair of symmetrical two pieces, a butt-joint piece is arranged on the side of the middle of the lock block, a wedge block is arranged at the end of the butt-joint piece, an oblique angle is arranged on the outer side end face of the wedge block, pin holes are formed in the two sides of a positioning hole in the butt-joint piece, and the pins are installed in the pin holes.

The invention relates to the technical field of bearings, in particular to a bearing of a harmonic reducer. The operation working condition of the harmonic reducer is relatively complex, and the phenomena of oil seepage and oil leakage are serious sometimes, so that sealing failure is caused. And meanwhile, the cross bearing is not provided with a retainer, so that the rigidity and the bending resistance of the cross bearing cannot meet expected requirements. A bearing of a harmonic reducer comprises two outer rings, and the two outer rings are doubly fastened by a fixing mechanism and a guide mechanism; inner rings are arranged in the two outer rings and extend out of the outer rings; a retainer with an inclined angle is arranged between the two outer rings and the inner ring, a plurality of roller pins are arranged in the retainer, and the roller pins are of a double-row structure; and one ends of the outer ring and the inner ring are provided with sealing mechanisms with keeping elasticity. The starting torque of the retainer can be optimized by more than 10%, which is favorable for saving energy and keeping the stability of the motor. And the arrangement of the double rows of roller pins and the retainer can reduce the overflow of grease.

The invention discloses a method for predicting dynamic mechanical properties of a tough difficult-to-machine material based on milling. The method comprises the following steps: firstly, optimizing and solving a normal shear angle of an oblique angle cutting shear plane through an iterative method: (a) setting an initial value of the normal shear angle; (b) calculating an undeformed chip thickness, a cutter instantaneous invasion angle, a cutting force component and a normal friction angle based on the normal shear angle initial value; (c) updating a normal shear angle calculation value; (d) calculating the error between the initial value and the calculated value of the normal shear angle, if the error is not within the allowable range, repeating the steps (a)-(d) until the error is within the allowable range, and outputting the final calculated value as the optimized normal shear angle; then, parameters such as the optimized normal shear angle are substituted into a related equation containing fracture toughness, yield strength and viscous toughness to solve the fracture toughness Gc of a workpiece material at a tool nose in the milling process, the yield stress sigma Y in a shear plane and the viscous toughness Ga of chip slippage at a tool-chip contact interface.

The invention relates to the technical field of optical detection, in particular to a focusing control method and system, detection equipment and a storage medium. The focusing control is realized by acquiring the mass center coordinate difference between the light spot corresponding to the real-time detection light beam and the standard light spot / monitoring light spot, determining the defocusing amount of the light spot based on the mass center coordinate difference, determining the oblique incidence angle adjustment amount through the defocusing amount, and adjusting the oblique incidence angle based on the oblique incidence angle adjustment amount. Focusing can be rapidly and accurately achieved, and meanwhile the size and the shape of a light spot can be monitored.

The invention discloses an electric arc fuse wire additive manufacturing method for a complex metal component with a protruding part, which comprises the following steps of: 1, three-dimensional modeling optimization: analyzing a three-dimensional model of the complex metal component; through local treatment, right-angle or oblique angle treatment and protruding part bottom supporting treatment, it is guaranteed that arc fuse wire additive manufacturing can be achieved; the optimized three-dimensional model is subjected to slicing treatment, and an electric arc fuse wire additive manufacturing path is obtained and optimized; and thirdly, the complex metal component with the protruding part is obtained through electric arc fuse wire additive manufacturing. According to the method, through three-dimensional modeling optimization, combined path optimization and additive manufacturing process parameter real-time adjustment, one-time additive manufacturing forming of the complex metal component with the protruding part is achieved, the continuity of the additive manufacturing process is guaranteed, the consistency of the overall performance of the complex metal component is improved, and the manufacturing method is simple in process, controllable and suitable for large-scale production. The method is suitable for the field of electric arc fuse wire additive manufacturing.

The invention provides a build-up rate intelligent prediction method and device, computer equipment and a storage medium, and the method comprises the steps: collecting the drilling and measurement data of an actual measurement point, and carrying out the data processing of the drilling and measurement data, and obtaining time series data and non-time series data; inputting the time series data and the non-time series data into a preset double-input GRU model, and calculating the time series data and the non-time series data by using the preset double-input GRU model to obtain an azimuth angle of the actual measurement point and a hole drift angle of the actual measurement point; and extracting well depth data of the actual measurement point from the drilling measurement data, and calculating the build-up rate of the actual measurement point according to the well depth data, the azimuth angle and the hole drift angle. According to the method, the skew rate is calculated by utilizing the preset double-input GRU model, so that the problems that multiple assumed conditions of a mechanism model are difficult to meet at the same time, underground mechanical behaviors are complicated and difficult to describe accurately are solved to a certain extent, and the problems that an intelligent model cannot focus key features and the generalization performance is insufficient are solved, and thus the accuracy of calculating the skew rate is improved.

A fluorescence microscopy inspection system includes light sources able to emit light that causes a specimen to fluoresce and light that does not cause a specimen to fluoresce. The emitted light is directed through one or more filters and objective channels towards a specimen. A ring of lights projects light at the specimen at an oblique angle through a darkfield channel. One of the filters may modify the light to match a predetermined bandgap energy associated with the specimen and another filter may filter wavelengths of light reflected from the specimen and to a camera. The camera may produce an image from the received light and specimen classification and feature analysis may be performed on the image.

The present invention provides a carbon dioxide phase change directional pressure relief fracturing device for excavation and a method for using the same. The fracturing device includes a liquid storage pipe for storing liquid carbon dioxide, a filling valve, a heater and an explosion relief head; the explosion relief head includes an explosion relief pipeline of a Y-shaped structure, including a first pipeline, a second pipeline and a third pipeline that are interconnected, one end of the first pipeline is connected to the liquid storage pipe, the other end of the first pipeline is obliquely connected to the head end of the second pipeline and the third pipeline, the ends of the second pipeline and the third pipeline face the free surface of the tunnel to be excavated, the ends of the second pipeline and the third pipeline are explosion relief ports, carbon dioxide gas is vented through the explosion relief ports, and the angle between the explosion relief port and the borehole axis is less than 90°. The fracturing device is fixed in an inverted manner in the borehole, so that the explosion relief direction can impact the borehole wall along an oblique angle during the explosion process, and has the advantage that the shock wave is released toward the orifice along the reflection angle, thereby solving the problem of the stability of the existing fracturing device in the borehole. It not only reduces energy loss, but also eliminates the risk of fracturing device recoil.

The invention provides a highly-deviated horizontal well longitudinal wave time difference anisotropy correction method and system, and the method comprises the steps: building a longitudinal wave time difference anisotropy inversion model based on an elliptic equation, building a longitudinal wave time difference correction chart, and building a longitudinal wave anisotropy coefficient logging interpretation model through the longitudinal wave time difference logging information of multiple wells at the same layer in a research area; and finally, longitudinal wave time differences in the vertical direction and the horizontal direction which are not influenced by anisotropy are calculated by combining the longitudinal wave time differences measured in the high-inclination / horizontal well, natural gamma and a hole drift angle logging curve. The method has both theoretical basis and actual data, the objective rule obtained through combination of theory and reality is high in universality and precision, can be operated by general interpretation personnel, and is beneficial to rapid and large-scale application in production.

The invention discloses a visual positioning method for alignment assembly of a display screen module, and particularly relates to the technical field of automatic assembly. Acquiring multi-source image data including an orthographic vision image, an oblique angle projection image and a near-infrared image; carrying out image enhancement and feature fusion processing, and constructing a multi-dimensional joint visual feature matrix of structure edges, illumination reflection textures, material mark points and the like; identifying module key identification points based on the feature information, and constructing an adaptive error compensation model to predict and correct a positioning error; dynamically adjusting the pose of the identification point through a real-time image sequence, and generating an optimal alignment control path; in the path execution process, image feedback and encoder information are fused to monitor the positioning precision in real time, and a dynamic path re-planning mechanism is triggered to realize micro correction; the method can be widely applied to a high-precision and high-consistency display module automatic assembly scene.

A waveguide display system include a waveguide, an input coupler configured to couple display light into the waveguide, a first pupil expander, and a second pupil expander. The first pupil expander is configured to deflect, at a first plurality of locations along a first direction, the display light towards the second pupil expander. The second pupil expander is configured to deflect, at a second plurality of locations along a second direction different from the first direction, the display light from the first pupil expander towards an eyebox of the waveguide display system. At least one of the input coupler, the first pupil expander, or the second pupil expander includes transflective mirrors that are tilted within the waveguide such that the transflective mirrors are inconspicuous when viewed from an oblique angle.

The invention discloses a bubble defect detecting and positioning system and method based on X-ray enhanced partial discharge, and belongs to the technical field of nondestructive testing of insulating materials, the system comprises a shielding box slidably mounted on a three-dimensional linear guide rail, an X-ray machine and a red laser are embedded in the shielding box, and double-oblique-angle cameras are mounted on two sides of the three-dimensional linear guide rail; the laser positioning synchronization device is installed on the movable collimation X-ray scanning module, and the movable collimation X-ray scanning module emits an X-ray beam towards the basin-type insulator to be detected; the laser positioning synchronization device emits a laser beam towards the basin-type insulator to be detected; the laser beam is coaxial with the X-ray beam; the double-oblique-angle camera shoots the basin-type insulator to be detected; the pressurization circuit is respectively connected with the pressurization electrode and the partial discharge detection system, and the pressurization electrode is electrically contacted with the basin-type insulator to be detected; the intelligent control platform is connected with the voltage increasing circuit, the movable collimation X-ray scanning module, the laser positioning synchronization device, the double-oblique-angle camera and the partial discharge detection system.

The utility model discloses corner cutting equipment for home furnishing manufacturing, which comprises a mounting rack, two pressure bearings are fixedly embedded in the inner side wall of the mounting rack, the inner rings of the two pressure bearings are fixedly connected with a rotating screw rod together, and the right side surface of the mounting rack is fixedly connected with a rotating motor. According to the device, a sealing bearing, an L-shaped fixing rod and an electric hydraulic rod are arranged, the pushing force of the electric hydraulic rod is utilized, a plate can be conveniently fixed, meanwhile, the electric hydraulic rod can be conveniently and randomly moved to a designated position, and an L-shaped fixing frame can conveniently drive the plate to move; by arranging the L-shaped mounting plate, the pin shaft, the mounting hole, the connecting plate and the positioning screw, the positioning screw is matched with the positioning hole, and the connecting plate is in sliding connection with the inner wall of the mounting hole, the connecting plate can be conveniently and randomly adjusted, so that the angle of the cutting disc can be changed according to different requirements; and therefore, a user can conveniently cut the oblique angle of the plate.

The present invention relates to the technical field of automotive part forming, and specifically discloses a stamping and welding process for a closed torsion beam longitudinal arm. S1. Drawing: Form a partial product profile of the longitudinal arm by means of stamping and drawing; S2. Trimming: Remove the redundant material, and at the same time stamp an oblique angle on the edge of the sheet metal; S3. Stamping and flanging; S4. Final stamping forming: Use a final forming die to directly stamp and close the free end of the product with a U-shaped cross-section. The final forming die includes an upper die and a lower die. The lower die is in concave-convex fit with the drawing part of the product. A cavity matching the shape of the designed product is provided on the upper die. Guide inclined surfaces are provided on both sides of the cross-section of the cavity of the upper die. During the die closing process of the final forming die, the oblique angle at the free end of the product automatically moves along the edge of the cavity of the upper die until the free end is closed at the top of the cavity; S5. Welding: Weld at the closed position of the product. This solution is used to solve the problem of low forming efficiency of the longitudinal arm existing in the current method of forming the longitudinal arm by means of tube rolling.

The utility model relates to the technical field of monitoring devices, and discloses a reservoir level monitoring device which comprises an installation frame, a fixing plate is fixedly installed at the top end of the installation frame, a base is arranged on the upper surface of the fixing plate, and a fixing assembly is arranged between the fixing plate and the base. The fixing assembly comprises four openings formed in the circumferential direction of the upper surface of the fixing plate at equal intervals. The electric telescopic rod ascends to drive the driving plate to move upwards, the driving plate drives the driving rod to move upwards, the driving rod drives the rotating plate to move close to each other around the rotating fulcrum through the driving groove, the rotating plate drives the pressing angle to abut against the oblique angle, and the base is firmly fixed to the upper surface of the fixing plate through abutting of the pressing angle and the oblique angle. When the base is fixed through the device, a plurality of bolts do not need to be tightened and loosened, the installation process is simple and easy to operate, and manpower and time consumption is reduced.

An endoscopy system that includes a computer system with a high definition display monitor and a handheld portion. The handheld portion includes a re-usable handle portion and a single use portion that is configured to be disposed of following a single use. The single-use portion includes a substantially straight elongated cannula with an imaging module and illumination modules at its distal tip. The imaging module is mounted such that its direction of view (DOV) is at an oblique angle from the main longitudinal axis of the cannula.

Systems and methods are provided for improving overall vision in patients suffering from a loss of vision in a portion of the retina (e.g., loss of central vision) by providing symmetric or asymmetric optic with aspheric surface which redirects and / or focuses light incident on the eye at oblique angles onto a peripheral retinal location. The intraocular lens can include a redirection element (e.g., a prism, a diffractive element, or an optical component with a decentered GRIN profile) configured to direct incident light along a deflected optical axis and to focus an image at a location on the peripheral retina. Optical properties of the intraocular lens can be configured to improve or reduce peripheral errors at the location on the peripheral retina. One or more surfaces of the intraocular lens can be a toric surface, a higher order aspheric surface, an aspheric Zernike surface or a Biconic Zernike surface to reduce optical errors in an image produced at a peripheral retinal location by light incident at oblique angles.

A method of increasing the interference contrast in interferometric scattering optical microscopy. The method comprises providing a particle detection region comprising a chamber or channel having a boundary defined by one or more interfaces, illuminating a particle in the particle detection region with coherent light using an objective lens such that the light is reflected from the interface and scattered by the particle, capturing the reflected light and the scattered light using the objective lens, and providing the captured reflected and scattered light to an imaging device to image interference between the reflected light and the scattered light. The particle is illuminated by coherent light at an oblique angle to the interface.

The utility model relates to the technical field of walking type electric stackers, and discloses an anti-toppling structure of a walking type electric stacker, which comprises a base, a stacker body is arranged on the upper surface of the base, an anti-toppling plate is arranged on the inner wall of the stacker body, a second groove is formed in the anti-toppling plate, and the second groove is communicated with the base. A rotating shaft is fixedly connected to the interior of the fork truck body, a sliding rail is fixedly connected to the inner wall of the anti-falling plate, a rotating disc is arranged on the outer wall of the sliding rail, a sliding block is slidably connected to the inner wall of the sliding rail, a limiting column is fixedly connected to the inner wall of the sliding block, and a first groove is formed in the rotating disc; and the inner wall of the rotating disc is fixedly connected with a threaded rod. According to the utility model, the nut is rotated to drive the threaded rod to rotate, and then the turntable rotates along with the rotation of the threaded rod, so that the purpose of forming an oblique angle between the anti-toppling plate and the base is finally realized, and the anti-toppling plate supports the stacker body, thereby achieving the effect of preventing the stacker body from toppling due to the change of the gravity center in the stacking process.

The invention discloses an optical receiving assembly, an optical module and a communication device, the optical receiving assembly is used for receiving an optical signal transmitted by an APC optical fiber, the optical receiving assembly is composed of a light guide element and a photoelectric detector, the emergent end surface of the APC optical fiber is an inclined surface, and the emergent light beam enters the light guide element at an inclined angle; the light path adjusting structure is arranged in the light guide element, the direction of the light path can be changed, and the light beam emitted by the APC optical fiber can enter the photosensitive surface of the photoelectric detector at a vertical angle after being transmitted by the light guide element. According to the optical receiving assembly, the offset and loss of the optical signal in the transmission process can be reduced, the sensitivity and the signal transmission efficiency of the optical receiving assembly are improved, and the performance of the whole optical module is further improved; and the overall performance of the communication equipment is optimized, so that the communication equipment is more suitable for high-speed and large-data-volume transmission requirements.

The invention relates to the field of mowers, and provides a collision detection method and a collision detection structure. A first polarity Hall plate is rotatably mounted on a shell in the height direction, so that an inclined angle is formed between the first polarity Hall plate and the front-back direction; a first magnetic piece is arranged on the buffer frame and located on one side of the first polarity Hall plate, a first distance is formed between the first magnetic piece and the first polarity Hall plate in the front-back direction, and a second distance is formed in the left-right direction; the ratio of the first distance to the second distance is changed by adjusting the inclination angle of the first polarity Hall plate, so that the detection sensitivity in the front-back direction and the left-right direction is controlled. A first polarity Hall plate is rotatably arranged in the height direction, and a first magnetic piece and the first polarity Hall plate form a first distance in the front-back direction and form a second distance in the left-right direction; the proportion of the first distance and the second distance is controlled by adjusting the inclination angle of the first polarity Hall plate, so that the collision source direction is distinguished, and the sensitivity in the front direction and the left-right direction is controlled.

This invention provides a system and method for imaging a surface, moving in a motion direction, with a vision system having at least a first camera, defining an optical axis, transmitting acquired images of the surface to a vision system processor. At least a first bar illuminator extends in a direction transverse to the motion direction. The bar illuminator defines opposing, interleaved arrays of localized solid state light sources (e.g. LEDs). Each of the arrays is oriented to propagate light at a respective, opposing oblique angle with respect to the optical axis, which can be independently activated as respective image(s) are acquired. The first bar illuminator is oriented with respect to the surface so as to project arrays that propagate light along a first plane defining a first non-parallel angle versus the optical axis. The two non-parallel angles can each define opposing angles with respect to the optical axis.

The invention discloses a steel pipe piece vertical plate multi-angle cutting rapid positioning device which comprises a plurality of cutting workbenches, connecting plates are arranged in the cutting workbenches, a plurality of cutting sawtooth plates are connected to the connecting plates in a clamped mode, waste grooves are formed among the cutting sawtooth plates, and waste boxes are arranged at the bottoms of the cutting workbenches. An angle adjusting piece is arranged on the cutting workbench, the vertical plate is positioned on the cutting sawtooth plate through the angle adjusting piece, a cutting mechanical arm is arranged on the front side of the cutting workbench, and a laser cutting head is arranged on the cutting mechanical arm. The vertical plate is placed on the cutting sawtooth plate, meanwhile, the angle adjusting piece is used for positioning the vertical plate, when bevel angles of different angles need to be cut, only the connecting plate needs to be rotated, then the vertical plate is driven to rotate, then the laser cutting head is used for cutting the vertical plate at the corresponding angle, and the structure can be adjusted through the angle adjusting piece; and the vertical plate is positioned at different angles and is matched with cutting of the laser cutting head, so that different oblique angles are cut, and the applicability is improved.

A three-dimensional (3D) display, system, and method of fabrication and use thereof are described. The display includes a display panel having an array of subpixels of different colors that displays an image to a viewer. A ratio of spacing between subpixels of a particular color are different between orthogonal directions of the array, for example between 4:3 and 3:4. The subpixels can have a chevron, pentile or diamond pentile shape. Subpixels of each color in the diamond pentile subpixel arrangement have respective different pixel sizes. A parallax-generating optic directs light to the viewer and is invariant along an optical axis having a slant angle relative to an axis of the array of subpixels that is near but not equal to 45 degrees. The parallax-generating optic includes a lenticular lens array or a parallax barrier having transmissive slits.

The utility model relates to the technical field of plastic trays, and discloses an integrated shared tray with a matts-shaped bottom, which comprises an upper plate surface, the matts-shaped bottom and bottom feet, the upper plate surface, the matts-shaped bottom and the bottom feet are integrally formed, the lower end of the upper plate surface is connected with the bottom feet, the bottom feet are connected with the matts-shaped bottom, and the upper plate surface is connected with the upper plate surface. The plane of the upper plate face is composed of a grid formed by a plane shaped like a Chinese character'ri 'and block-shaped reinforcing ribs, the bottom face of each block-shaped reinforcing rib is an inclined face, a fork inlet assembly is fixedly arranged at the front end of the bottom shaped like the Chinese character'tian', sharp-angled edges are fixedly arranged at the inner end of the bottom shaped like the Chinese character'tian ', and oblique angles are arranged on cross beams of the bottom shaped like the Chinese character'tian'. According to the integrated shared tray with the bottom shaped like the Chinese character'tian ', the upper plate face is designed to be the large plane, enough space is guaranteed to prevent goods of various shapes and sizes, meanwhile, the large plane is assembled with the anti-skid plane, optimization treatment is conducted, and the purposes of skid resistance, durability, easy cleaning and the like are achieved so as to adapt to different environments and use scenes.

There is provided a processor device that performs a type determination method for an endoscope by a processor using an endoscope color adjustment jig, the endoscope color adjustment jig including an insertion portion that includes at least one insertion hole into which a distal end portion of the endoscope is inserted, a lid portion that is disposed to face the insertion portion in an insertion direction of the distal end portion, and an outer peripheral portion that is in contact with the insertion portion and the lid portion to form an internal space, the lid portion including a chart that includes a mark on an inner surface facing the internal space, in which the processor is configured to, based on a shape of the mark imaged by the endoscope inserted from the insertion portion, determine an oblique angle of the endoscope.

A paper cutter is disclosed, including a barrel. The barrel is configured with an opening on one side, and a bottom of the opening is configured to be mounted with a removable blade. The removable blade is composed of a detachable base, a paper guiding slot and a blade. The paper guiding slot is configured on a top of the detachable base, the blade is mounted on an inside of the paper guiding slot at an oblique angle, and the barrel is configured with a groove on an inside wall. The present disclosure belongs to the technical field of a cutting device for paper products, specifically refers to a paper cutter, it is easy to replace blade accessories, the removable blade is placed separately to ensure that there is no exposure and also can ensure safety. The paper cutter also has high cutting efficiency and a flat cutting surface.

A near-eye display includes a light-guide optical element (LOE) (10) having first and second major external surfaces (11A, 11B) that are planar and mutually parallel. An image projector (2) introduces into the LOE illumination corresponding to an image so that the illumination propagates within said LOE by internal reflection at the major external surfaces. A coupling-out arrangement couples the illumination out of the LOE towards the eye of the observer. The coupling-out arrangement may be a set of mutually-parallel, partially-reflective surfaces (12A) deployed at an oblique angle within the LOE. Various arrangements for suppressing reflections of ambient light sources include obstructing baffles oriented so as to avoid reduction of peripheral field of view, various non-reflective coatings and various deployments of polarization filters.