Abstract: An optical path folding element includes an incident surface, a path folding surface and an exiting surface. The incident surface allows a light ray to pass into the optical path folding element. The path folding surface folds the light ray from the incident surface. The exiting surface allows the light ray to pass through and depart from the optical path folding element. At least one of the incident surface and the exiting surface includes an optical effective portion and at least one engaging structure symmetrically disposed around the optical effective portion. The engaging structure includes an annular surface portion and an inclined surface portion. The annular surface portion surrounds the optical effective portion, and the inclined surface portion is located between the annular surface portion and the optical effective portion. An angle between the annular surface portion and the inclined surface portion satisfies a specific condition.

Abstract: An augmented reality (AR) display apparatus includes an outputter that outputs first radiation including visual information in a predetermined spectrum, a polarizing plate that absorbs a first s-polarized radiation from the first radiation and transmits a first p-polarized radiation and an optical layer that reflects at least a portion of the first p-polarized radiation incident on a first side of the optical layer with a wavelength corresponding to the predetermined spectrum.

Abstract: An optics arrangement for an endoscope is provided. The optics arrangement images an object situated in front of its distal end to the proximal end of the optics arrangement along a principal beam path having an optical axis. The optics arrangement is designed both for light from the visible spectrum and for light from the near infrared. The optics arrangement includes an aperture stop with a reflection layer in the principal beam path. The reflection layer reflects light from the visible spectrum and transmits light from the near infrared. The reflection layer is inclined in relation to the optical axis.

Abstract: To provide an image display device that is advantageous in terms of a reduction in deterioration in image quality due to birefringence in an optical element of an ocular optical system in which polarized light is used, the image display device includes an ocular optical system including a polarization element and configured to guide light from an image display element toward an eyeball of an observer. The ocular optical system includes at least one optical element that has a forming gate mark in a part of an outer periphery. The forming gate mark is disposed in a direction of an apex of an image display region of the image display element with respect to a point on an optical axis of the ocular optical system in a cross section perpendicular to the optical axis of the ocular optical system.

Abstract: A camera module, a mobile terminal and a method of controlling a camera module are provided. The camera module includes a module support, a driving device, a first reflector, a second reflector and a lens module. The first reflector, the second reflector and the lens module are in the module support. Based on the position arrangement and the connection of the multiple components including the module support, the two reflectors, the lens module and the driving device, the lens module alternately collects light passing through the first light inlet and light passing through the second light inlet, so that the camera module alternately has the function of the front camera and the function of the rear camera, and the camera module has the same high quality imaging effect in all directions.

Abstract: A dichroic prism assembly (P1-P7) configured to receive light from an object image through an entrance face of the dichroic prism assembly, includes a first prism (P3) and a further dichroic prism assembly (P5, P6, P7) for splitting light in three light components. The first prism has a cross section with at least five corners, and each corner has an inside angle of at least 90 degrees. The corners of the first prism are designed so that an incoming beam which enters the entrance face in a direction parallel to a normal of the entrance face is reflected twice inside the prism and exits the prism through an exit face parallel to a normal of the exit face.

Abstract: A backlight unit may include a turning film that receives light from a light guide layer. The turning film may have a plurality of elongated protrusions that extend across the turning film. Each protrusion may have a concave surface. The concave surface may be a curved surface that curves inward towards the interior of the turning film. Light from the light guide layer may pass through the turning film and be reflected towards a viewer by the concave surfaces of the protrusions. In a liquid crystal display, the turning film may be interposed between the light guide layer and a lower polarizer. In certain embodiments, the turning film may be the only optical layer interposed between the light guide layer and the lower polarizer. In other embodiments, the turning layer and a diffuser layer may be the only optical layers interposed between the light guide layer and the lower polarizer.

Abstract: Endoscopic light refraction imaging techniques are described for configuring a viewing trocar and/or angled endoscope with a light refracting element, such as glass and/or plastic prism for instance. The light refracting element can be utilized in and/or with the viewing trocar to refract (i.e., bend) light passing into the trocar through the trocar's window. As a result, the angled endoscope's field of view can be substantially aligned with the field of view of the trocar's window, thus allowing the angled endoscope and viewing trocar to be used together to create ports in a patient, including initial ports of endoscopic surgical procedures.

Abstract: An optical film to visually reduce frame size of individual display units within a single large display includes four film portions connected to each other to form a rectangular frame of each individual display unit. Each film portion has strip-shaped micro-structures of triangular cross-section, and includes a bottom surface, a first side surface, and a second side surface. The bottom surfaces of the micro-structures are connected to each other. The first side surfaces and the second side surfaces are obliquely connected, the second side surface of one micro-structure being at the outermost side of each film portion. Angle ?1 between the first side and bottom surface of each micro-structure is less than angle ?2 between the first side surface and the second side surface and the sum of first and second angles ?1 and ?2 is less than 90°.

Abstract: A device includes a substrate and a plurality of unit pixels disposed in and/or on the substrate, arranged in a honeycomb pattern and separated from one another by a deep trench isolation (DTI) layer. The plurality of unit pixels may include a group of unit pixels radially arranged around and equidistant from a central unit pixel.

Abstract: An eyepiece includes a focusing apparatus for positioning the area perceived as in focus by the relaxed human eye and for correcting axial ametropia of an eye of a user of the eyepiece and a correction apparatus for adjustable correction of an astigmatism of an eye of a user of the eyepiece.

Abstract: A reconfigurable sled for a mobile device with camera is provided. The reconfigurable sled may be moved into different configurations in order to facilitate either normal or specialized use. For example, in a first configuration, the mobile device's camera is unobstructed and imaging may proceed normally. In a second configuration, on the other hand, the camera's imaging direction may be repositioned by a reflective element in the camera's optical path. The reflective element provides feedback to the mobile device via visible markings that may be imaged by the camera and detected by the mobile device. If the mobile device determines that the mirror is in the optical path, then the mobile device may respond to accommodate the mirror and enable a function, like reading an indicium.

Abstract: This patent specification describes a barcode-reading system for a mobile device. The mobile device includes a camera and a white illumination source on the backside of the mobile device. The system includes a barcode reading accessory with at least one reflective surface folding both the field of view of the camera and the field of illumination of the mobile device towards a target area beyond the top side of the mobile device.

Abstract: A camera for a vehicle, the camera including: an image sensor; and a camera lens system for imaging a coverage region on the image sensor; the camera lens system having at least one lens; and the camera lens system and the image sensor determining an optical axis of the camera. In this connection, The camera lens system further includes a nonplanar reflector element which deflects the optical axis of the camera.

Abstract: Systems and methods for capturing images are disclosed. An image capture device includes two or more apertures for directing light to an image sensor device. In some embodiments, each of the apertures admits light from a different direction relative to the image sensor device. Some embodiments include one or more electrically switchable mirror elements configured for directing light from at least one of the one or more apertures to the image sensor. Upon application of a first signal, a first electrically switchable mirror element enters a reflective mode for reflecting light from a first aperture of the one or more apertures to the image sensor device. Upon application of a second signal, the first electrically switchable mirror element enters a transmissive mode for transmitting light from a second aperture of the one or more apertures to the image sensor device.

Abstract: Exemplary embodiments of the present invention relate to a method for fixing an image sensor to a beamsplitter. An exemplary method comprises placing a first fixative agent comprising an ultraviolet adhesive between the image sensor and the beamsplitter and positioning the image sensor relative to the beamsplitter. The position of the image sensor is initially fixed relative to the beamsplitter by the first fixative agent. The exemplary method further comprises securing the image sensor to the beamsplitter with a second fixative agent.

Abstract: A photographing apparatus includes: a lens unit; a light transmission adjustment unit that adjusts light transmittance of light that passes through the lens unit; a photographing unit that is disposed a reflected light path of the light transmission adjustment unit and that generates an image data according to received light, and a view finder that is disposed on a transmitted light path of the light transmission unit.

Abstract: An image redirection system having a case that includes a body configured to removably attach to a mobile device, and an optical housing on the body, the optical housing configured to position one or more optical elements over the mobile device lens and flash unit when the case is attached to the mobile device. The optical housing is configured to enable one-handed operation such that a user can deploy and retract the optical housing with only one digit of a hand that holds the case and enable operation of the camera with another finger or thumb of the holding hand.

Abstract: A compressive imaging system including a light modulator, a light sensing device and a TIR prism. The TIR prism is configured to receive an incident light beam, to provide the incident light beam to the light modulator, to receive a modulated light beam MLB from the light modulator, and to direct the modulated light beam onto a sensing path. The light sensing device receives the modulated light beam (or at least a portion of the modulated light beam) and generates an electrical signal that represents intensity of the modulated light beam (or the “at least a portion” of the modulated light beam). The TIR prism may reduce a distance required to separate the incident light beam from the modulated light beam.

Abstract: An image sensor includes a first imaging pixel for a first color having a photosensitive region disposed within a substrate of the image sensor and a second imaging pixel for a second color that is different from the first color having a photosensitive region disposed within the substrate. A refraction element disposed adjacent to the substrate, so that the refraction element refracts light of the first color to the photosensitive region of the first imaging pixel and refracts light of the second color to the photosensitive region of the second imaging pixel.

Abstract: An image capturing device includes a cube prism and three image capturing units. The cube prism includes an incident surface, a first exiting surface, a second exiting surface, and a third exiting surface orthogonal to each other, and further includes a first splitting surface, a second splitting surface, a third splitting surface, and a forth splitting surface orthogonal to each other. The light incident into the incident surface is split by the four splitting surfaces into monochromatic lights, and the monochromatic lights respectively exit from the three exiting surfaces to be received by the image capturing units to form images. The images can be combined as a multicolored image. Accordingly, the light-use efficiency and the image resolution can be improved, and the color fault of the image can be avoided.

Abstract: An optical apparatus includes a catoptric element that causes incoming light traveling from an object in a direction of a first optical axis to be refracted in a direction of a second optical axis, a motor that drives an optical member provided on the second optical axis, and a stereo microphone including a left-channel microphone and a right-channel microphone that are provided on a side of the optical apparatus opposite the motor with respect to the second optical axis when seen from an object side and arranged in a direction substantially parallel to the second optical axis.

Abstract: A lighting device configured to efficiently combine light beams emitted from a plurality of light sources, and to emit high output light while minimizing light loss, and a projection type display apparatus including the lighting device. The lighting device includes: a first light source and a second light source; two converging lenses for converging light beams emitted from the first and second light sources; two right-angle prisms for bending the light beams emitted from the first and second light sources; and a composite rod integrator for combining the light beams emitted from the first and second light sources. Between an exit surface of each right-angle prism and an incident surface of the composite rod integrator, a predetermined air gap is provided. The focal point of each converging lens is located on an incident surface of each right-angle prism.

Abstract: A biometric information acquisition apparatus includes: a light guide that guides a light beam through a plurality of light reflective surfaces; and an image pickup unit that receives the light beam output from the light guide and captures a subject image. The light guide includes an input surface that receives the subject image and is provided at a front surface side; a first light reflective surface that is opposed to the input surface and is provided at a back surface side; and a second light reflective surface that extends in a thickness direction of the light guide. A subject image can be acquired within a desired range by employing the light guide, while suppressing an increase in size of the biometric information acquisition apparatus.

Abstract: An image pickup unit according to the present invention, includes a solid-state image pickup device provided with a light receiving portion for receiving photographing light refracted and reflected by a reflection surface of an optical reflection member. The image pickup unit also includes a protection member which is surface-joined to and to protect at least the area of an effective reflection surface within the reflection surface by which the photographing light is refracted and made incident on the light receiving portion. Thereby, when the image pickup unit is provided in an electronic endoscope including the optical component for refracting and reflecting the photographing light, it is possible to improve the assembling property of the image pickup unit including the optical component, and possible to prevent the optical component from being damaged under various environment.

Abstract: Image data pixels indicative of the pixels in a noise-reduction target area having a size of 5×5 pixels is extracted from a plurality of types of CCD-RAW data having red, green and blue color components. A filter for reducing uncorrelated noise is calculated. Uncorrelated noise is removed by performing a filter operation using the calculated filter while correlativity of the CCD-RAW data is maintained. These processing steps are repeated for one frame of CCD-RAW data. After uncorrelated noise has been removed, spatial pixel processing such as an aperture correction is applied.

Abstract: Light-splitting elements are arranged in at least two columns and two rows to form two pairs 1a, 1b and 1c, 1d. Each element splits incident light into light rays and makes them fall on a portion of a photosensing section right under itself and an adjacent photosensitive cell. The element 1a splits the incident light so that a primary color ray C1 and its complementary color ray C1? enter an adjacent cell 2b and an underlying cell 2a, respectively. The element 1b makes a primary color ray C2 and its complementary color ray C2? enter an underlying cell 2a and an adjacent cell 2a, respectively. The element 1c does the same as the element 1b. And the element 1d makes a primary color ray C3 and its complementary color ray C3? enter an adjacent cell 2c and an underlying cell 2d, respectively. These photosensitive cells 2 perform photoelectric conversion, thereby outputting an electrical signal representing the intensity of the incident light.

Abstract: An apparatus includes a zoom lens and an image pickup element. The zoom lens includes an optical path reflecting lens group including a reflecting member and having a positive refracting power, a movable negative lens group that is disposed in the optical path on the image side of the optical path reflecting lens group, has a negative refracting power, and moves during zooming, a movable positive lens group that is disposed in the optical path on the image side of the movable negative lens group, has a positive refracting power, and moves during zooming, and an aperture stop disposed in the optical path between the movable negative lens group and the movable positive lens group. The optical path reflecting lens group is a lens group located closest to the object side in the zoom lens.

Abstract: A portable electronic device includes a flat display, a transparent window, an optical element, an optical zoom lens set and an image sensing element. The flat display includes a display panel with a viewing direction. The transparent window, the optical element, the optical zoom lens set and the image sensing element are all configure in the outer frame of the flat display. The transparent window and the optical element correspond to each other and align in the viewing direction. The optical zoom lens set includes multiple lenses configured at one side of the optical element. The lenses move along a focusing direction to modify the focusing length. The focusing direction is substantially perpendicular to the viewing direction.

Abstract: An image rotation adapter that is configured to be detachably mounted between an image capturing lens and a camera main body in a camera and includes a first prism configured to invert the object image passed through the image capturing lens by reflecting an odd number of times object light passed through the image capturing lens and a second prism that is supported rotatably about the optical axis, and that is configured to further invert the object image inverted by the first prism by reflecting an odd number of times the object light passed through the first prism; an operation device configured to perform an operation to rotate the second prism; and a relay optical system configured to re-form the object image passed through the second prism on the light receiving surface of the image pickup device.

Abstract: An image pickup optical system including: a first prism including: a first incident surface where subject beam enters; a division surface for dividing the beam from the first incident surface into image-pickup beam and focus-detection beam; and a first exit surface from which reflection beam reflected on the division surface, the image-pickup beam or the focus-detection beam, exits; and a second prism including: a second incident surface on which transmission beam passing through the division surface, the image-pickup beam or focus-detection beam, enters; and a second exit surface from which the transmission beam exits, wherein the reflection beam is reflected on the division surface, reflected on the first incident surface, and reflected on the division surface to reach the first exit surface, and satisfying 0.1<DA/DB<0.5, where DA and DB indicate beam diameters of beams toward the image pickup elements for focus detection and for image pickup.

Abstract: An imaging device includes an imaging optical system including at least one movable optical element; an image sensor, an imaging surface of which lies on an image-forming plane of the imaging optical system; a circuit board on which the image sensor is mounted; and an image processing circuit for processing an image signal output from the image sensor and a drive circuit for the movable optical element, both of the image processing circuit and the drive circuit are mounted on the circuit board. The image processing circuit and the drive circuit are disposed on the circuit board in that order from a side closer to the image sensor.

Abstract: An optical system is provided. The optical system comprises a first polarizing beamsplitter (PBS), a first reflecting image-forming device, and a first quarter-wave retarding element. An optical system is also provided that comprises an image-forming device, a reflective polarizing layer, at least a first birefringent element disposed on an optical path between the image-forming device and the polarizing layer, and a quarter-wave retarding element. Further provided is an optical system comprising a color combiner unit, at least two polarizing beamsplitters (PBSs), and a first quarter-wave retarding element. The present application also provides methods of compensating for birefringence in an image projection system.

Abstract: An imaging device includes a housing including first and second photographing apertures which are open toward opposite directions; an image pickup device provided in the housing; a main optical system forming incident light from the first photographing aperture onto an imaging surface of the image pickup device; and an insertable optical element movable between an insertion position in an optical path of a main optical system and a removed position out of the optical path of the main optical system, the insertable optical element constituting at least a part of a sub-optical system which forms incident light from the second photographing aperture onto the imaging surface when at the insertion position. When the insertable optical element is positioned in the insertion position, the sub-optical axis is offset from the main optical axis toward the removed position of the insertable optical element in the inserting/removing direction.

Abstract: To improve the consumer experience with portable electronic devices, a high-resolution digital camera function is incorporated into a multifunction portable electronic device. In exemplary embodiments, a clamshell portable electronic device, such as a mobile telephone, is provided with a digital camera/video function. The lens of the camera/video function is separated from an image sensor in a manner such that the two are not linearly aligned. Light coming through the lens is reflected by a reflective element, such as prism, onto the image sensor. The sensor is movable relative to a fixed position of the prism to provide an auto focus feature. In an exemplary embodiment, the sensor is movable along a portion of the width of the portable electronic device, the width being substantially greater in distance than the thickness of one of the clamshell portions.

Abstract: An image pickup apparatus includes an image-pickup optical system, three color separation prisms separating incident light guided by the image-pickup optical system into three-primary-color light components and emitting the light components, and three image pickup elements respectively receiving the three light components from the prisms so as to produce respective image signals. Of the three prisms, a first prism that first receives the incident light has an edge extending parallel to an incidence plane. The image-pickup optical system has a plate-like fixed aperture stop disposed between the first prism and a final lens, disposed closest to the first prism, of multiple lenses included in the image-pickup optical system. The fixed aperture stop has an aperture that limits the incident light. An edge section of the aperture has projections and depressions arranged at least in parallel to the edge, as viewed from an optical-axis direction of the final lens.

Abstract: A color separation filter (100), for a solid state image sensor includes a micro lens array (108) adapted to collect a full color spectrum light source (104), a mask layer (120) is attached to the micro lens array (108), the mask layer (120) includes plurality of openings (124), each opening is positioned in front of a single micro lens from the micro lens array. Additionally it includes a first array of prisms (204), each prism is positioned in front of each of the openings, a second array of prisms (212) is attached to the first array of prisms with an optical glue layer (208). Each prism from the first array of prisms is positioned in front of a prism from the second array of prisms to create a symmetrical optical path for the color spectrum light source (304).

Abstract: A projector includes an optical arrangement and a cooling arrangement. The optical arrangement includes a light source, a filtering component, a light modulation component and a projection lens. The filtering component filters the light emitted by the light source. The light modulation component modulates the light filtered by the filtering component to form an image. The projection lens projects the image formed by the light modulation component. The cooling arrangement is arranged relative to the optical arrangement to cool the optical arrangement. The cooling arrangement includes a blower, an air duct and a heat sink. The blower blows cooling air. The air duct guides the cooling air from the blower to the filtering component along an cooling air path. The heat sink is disposed in the cooling air path within the air duct and fixedly attached to the light modulation component to thermally contact with the light modulation component.

Abstract: A projector with reduced size and higher contrast includes a prism assembly, a light system, and a Digital Micro-mirror Device (DMD). Only In the “ON” state of DMD, the light from the light system reflects to a projection screen through the prism assembly and the DMD. The prism assembly includes two prisms and a medium layer. The prism assembly is appropriately designed so as to disable the light in the “OFF” state from reflecting to the projection screen by two-time total internal reflection in the prism assembly, and also to reduce the size of the projector.

Abstract: An image pickup device includes a color separation prism composed of prism members and which separates light into color components, solid-state image sensors fixed to the prism members, respectively, image sensor boards on which the solid-state image sensors are mounted, respectively, an image control board to which image pickup signals generated by the image sensor boards, respectively, are inputted, and a flexible board which is connected to the image control board. The flexible board includes a signal transmission layer connected to each of the image sensor boards and which contains transmission paths for transmitting the image pickup signals to the image control board, and a heat radiating layer formed of a high heat conductivity material which is connected to each of the solid-state image sensors and fixed to the signal transmission layer via an insulating layer to transfer heat generated in the solid-state image sensors.

Abstract: An image rotating adapter includes: a first prism forming a subject image transmitted through an imaging lens on a position; and a second prism further reversing the subject image reversed by the first prism. The adapter also includes: a rotation drive unit rotating the second prism; a control unit controlling the rotation drive unit; a rotation instruction unit instructing the control unit to start or stop rotation; a target position setting unit previously setting one or more target positions to stop the second prism; a preset instruction unit instructing the control unit to perform a preset function for moving the second prism to the target position; a speed control unit adjusting rotation speed of the second prism; and a detection unit detecting a rotation position and a rotation direction of the second prism.

Abstract: A lens barrel includes a fourth lens, a prism, and a sixth lens. The fourth lens receives a light flux incident along a first optical axis. The prism includes a reflecting surface reflecting the light flux passing through the fourth lens to a direction along a second optical axis intersecting with the first optical axis. The sixth lens receives the light flux reflected by the prism. A second group frame includes an opening portion, a prism retaining frame that is arranged in a more inner position than the opening portion and in which the prism is contained, and a plurality of adhesive pockets arranged on an area around the prism retaining frame and being open to the side of the opening portion. Adhesive agent is filled in the adhesive pockets.

Abstract: An image processing device and an image processing method capable of generating a moving image having a high resolution and a high frame rate are provided by suppressing the reduction in the amount of light incident on each camera.

Abstract: The shooting, recording and playback system 100 of the present invention receives incoming light 101, stores an image shot, and then subjects the image shot to be reproduced to resolution raising processing, thereby outputting RGB images with high spatial resolution and high temporal resolution (ROUT GOUT BOUT) 102. The system 100 includes a shooting section 103, a color separating section 104, an R imaging sensor section 105, a G imaging sensor section 106, a B imaging sensor section 107, an image shot storage section 108, an image shot writing section 109, a memory section 110, an image shot reading section 111, a spatial resolution upconverter section 112, a temporal resolution upconverter section 113, an output section 114, and a line recognition signal generating section 185. The system can get image data with high spatial resolution and high temporal resolution without getting the camera configuration complicated and without decreasing the optical efficiency.

Abstract: An image capture apparatus is provided. The image capture apparatus includes a prism that separates light incident through a lens into at least two color components of light to be output and an image capture device that converts light separated by and output from the prism into a captured image signal. The image capture apparatus includes a fixing plate attached to the image capture device mounted on a substrate. In addition, the image capture apparatus includes a plurality of fixing members for fixing an unattached surface of the fixing plate, which is unattached to the image capture device, on a side surface of the prism through an adhesive.

Abstract: Image data pixels indicative of the pixels in a noise-reduction target area having a size of 5×5 pixels is extracted from a plurality of types of CCD-RAW data having red, green and blue color components. A filter for reducing uncorrelated noise is calculated. Uncorrelated noise is removed by performing a filter operation using the calculated filter while correlativity of the CCD-RAW data is maintained. These processing steps are repeated for one frame of CCD-RAW data. After uncorrelated noise has been removed, spatial pixel processing such as an aperture correction is applied.

Abstract: A solid-state image sensor includes a first image sensing device, a first flexible substrate connected to the first image sensing device, a second solid-state image sensing device, and a second flexible substrate connected to the second solid-state image sensing device. The solid-state image sensing devices are disposed adjacently to each other such that light receiving surfaces are perpendicular to each other. The second solid-state image sensing device directly receives incident light. However, the first solid-state image sensing device receives the incident light reflected by a mirror. Electronic components are mounted on the two flexible substrates. The first flexible substrate is bent at two bending positions to face the second flexible substrate and electrically connected thereto.

Abstract: An image pickup apparatus and method is disclosed by which moving pictures of a high frame rate can be displayed. The image pickup apparatus for picking up moving pictures, includes: a distribution section for distributing light incoming through an optical lens to n directions; n image pickup elements for converting the light distributed by the distribution section into signals at time intervals of 1/m second to pick up images; and a control section for controlling timings at which the light is to be converted into the signals by the image pickup elements; the control section controlling the n image pickup elements to convert the light into the signals at timings successively displaced by 1/m×n second to pick up images.

Abstract: An image pickup device includes: a prism ii including light entrance holes (16, 16) and a light exit hole (17) for exiting incident light by refracting the incident light from the light entrance holes (16, 16) and; a lens (12) located on a light exit hole (17) side of the prism (11); a camera (13) located on an opposite side to the prism (11) with respect to the lens (12), and a base (14) that supports the prism (11), the lens (12), and the camera (13). The light exit hole (16) of the prism (11), the lens (12), and the camera (13) are arranged on the same optical axis (10). Any one or both of the prism (11) and the lens (12) and/or the lens (12) and the camera (13) are separated from each other.

Abstract: An optical system is provided. The optical system comprises a first polarizing beamsplitter (PBS), a first reflecting image-forming device, and a first quarter-wave retarding element. An optical system is also provided that comprises an image-forming device, a reflective polarizing layer, at least a first birefringent element disposed on an optical path between the image-forming device and the polarizing layer, and a quarter-wave retarding element. Further provided is an optical system comprising a color combiner unit, at least two polarizing beamsplitters (PBSs), and a first quarter-wave retarding element. The present application also provides methods of compensating for birefringence in an image projection system.