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

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

Abstract: A prism includes a prism base member having first and second faces intersecting with each other and including calcium fluoride, an antireflection film for oblique incidence formed on the first face of the prism base member, and an antireflection film for 0° incidence formed on the second face of the prism base member. Each of the antireflection film for oblique incidence and the antireflection film for 0° incidence includes a high-refractive-index layer with a relatively high refractive index, and a low-refractive-index layer with a relatively low refractive index. The high-refractive-index layer includes thorium fluoride and the low-refractive-index layer includes aluminum fluoride.

Abstract: A laser beam attenuator and a method of attenuating a laser beam are disclosed. The laser beam attenuator includes first and second prisms, a beam dump, and a light absorbing body. An input laser beam partially refracts and partially reflects at a first surface of the first prism to form first refracted and reflected laser beams. The first reflected laser beam partially refracts and partially reflects at a second surface of the second prism to form second refracted and reflected laser beams. The beam dump and the light absorbing body absorb the first and second refracted laser beams. Thus, the second reflected laser beam forms an attenuated laser beam.

Abstract: The invention features an apparatus and method for separating an optical beam including multiple wavelength components into targeted subsets of wavelengths by causing different subsets of wavelength components either to undergo a total internal reflection (TIR) at or to transmit through internal surfaces of refractive media.

Abstract: An illumination device for transmitting and/or distributing light with an extractor that extends distally into the interior of the light guide. The illumination device includes a hollow light guide including a wall having an inner surface and a structured outer side. The structured outer side includes a plurality of prisms defining grooves that extend along a length of the light guide. An extractor extends substantially along the length of the light guide and projects distally from the inner surface towards an interior of the light guide. The extractor is operative to cause light to be released through the wall of the light guide. A method of attaching the extractor is also disclosed.

Abstract: A plurality of magnets is provided in an illumination prism carrier of a transmitted light refractometer and a corresponding plurality of magnets is provided in a sample prism housing of the refractometer to align a light exit surface of the illumination prism relative to a sample surface of the sample prism and urge the optical surfaces together in an even and uniform manner. The magnets replace mechanical biasing arrangements for positioning the optical surfaces and function to consistently reproduce a measurement optical path in the instrument for improved accuracy and repeatability of measurements.

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

Abstract: An optical switch using a refractive optical element (52) to direct a light beam in selected directions upon operation of the switch. In a preferred embodiment, the refractive optical element is an optical wedge having a first portion (67) that transmits a light beam in a selected direction, and a second portion (50) that transmits the light beam in another direction, when the first or second portions of the optical wedge are switched into the path of the light beam. The refractive optical element is less sensitive to misalignment than a reflective element, for example. In a further embodiment, the optical wedge is combined with wavelength-selective filters (118, 128) and other components to provide a channel DROP and/or ADD function with high isolation.

Abstract: A line narrowing unit for use within an excimer or molecular fluorine laser resonator includes a dispersive prism having antireflection coatings on entrance and exit surfaces. Entrance and exit angles and an apex angle are increased to enhance the dispersive power of the prism, while the antireflective coatings limit reflective losses. Preferably, a laser beam makes a non-symmetric pass through said prism. The apex angle is preferably greater than 65°, or even 75°, and the angle of incidence and the exit angle of the beam are each preferably greater than 65°. A beam expanding prism configured for enhanced beam expansion has an apex angle between within a range of 37.5° and 42.5°, and a beam incidence angle at the entrance surface of more than 65°, and an antireflection coating on preferably both the entrance and exit surfaces.

Abstract: The present invention relates to a compact and high-performance prism optical system having, in order in which light rays pass from the object side, a first transmitting surface (4), a first reflecting surface (5), a second reflecting surface (6), a third reflecting surface (7), and a second transmitting surface (8). When an axial principal ray (1) is projected onto a plane defined by three points at which the axial principal ray (1) impinges on the first transmitting surface (4), the first reflecting surface (5) and the second reflecting surface (6), the projected axial principal ray forms an optical path that bends at two consecutive reflecting surfaces (5, 6) in the same direction with respect to the direction of travel of the rays and bends at the other reflecting surface (7) in a direction different from the direction of bending at the two reflecting surfaces. At least one of the three reflecting surfaces is a rotationally asymmetric surface.

Abstract: A beam deflector has first and second wedge prisms having refractive indices and geometries which are similar (in the case of the geometry to within arc minutes). The prisms are rotatable about an optical axis O defined by the direction of propagation of the incident light beam, to adjust the angle through which the incident beam is deflected. A third prism has a wedge angle which is greater than that of the first and second prisms by a factor of 2. When the directions in which the first and second prisms refract the beam away from the optical axis are aligned about the optical axis at notional angles of 0° and 90° respectively, and the third prism is aligned with its direction of refractive deviation at a notional angle of 225° about the optical axis, the light beam will pass undeviated through the deflecting device.

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

Abstract: A compact image pickup optical system satisfactorily corrected for chromatic aberration as well as decentration aberrations and capable of providing a clear image with minimal distortion even at a wide field angle. The image pickup optical system includes an image pickup optical element and a diffractive optical element, which are decentered with respect to each other. The image pickup optical element has at least three optical surfaces adjacent to each other. At least one of the three optical surfaces is formed from a curved surface. At least two reflections take place between the optical surfaces.

Abstract: A bar code reader having two reading windows, i.e., a bottom window and a side window. An increased number of scanning lines are used for constituting scanning patterns for scanning bar codes, and the arrangement of the optical system is contrived to decrease the whole size of the bar code reader and, particularly, to decrease the depth of the bar code reader. A source of laser light, a splitter for splitting the laser beam emitted from the laser light source into two, a reflection mirror for transmitting one beam from the splitter to a polygon mirror, the polygon mirror which rotates to scan the incident laser beam, a mirror system for emitting the beam reflected by the polygon mirror through the reading window, and a focusing member for focusing the beam reflected by the bar code onto a detector that detects the beam reflected by the bar code, are arranged on the same line in the bar code reader. By using a concave mirror, furthermore, the beam reflected by the bar code is folded back to one detector.

Abstract: A prism for a portable optical device is provided. The optical device is used for producing a wide-angle big-size virtual image of a picture from a mini-size high-resolution display and is usually used at an eye relief of only a few centimeters by wearing it on eyes or held closely to eyes with a hand. With the prism of the optical device, a magnified virtual image of the picture on the small display is projected onto a position beyond a distance of distinct vision of the user, so that the user could utilize a mini-size display and other video and audio instruments carried along the user to enjoy a picture on a wide-angle and big-size screen.

Abstract: Viewing aids useful for doors and windows, especially in aeroplanes, comprising as an essential element a pane made of a transparent material, which pane has at least one optically active surface comprising a plurality, i.e. at least two, of prisms, or a Fresnel lens, or a combination of both.

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

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

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

Abstract: A counter-rotating anamorphic prism pair assembly with variable spacing allows the simultaneous adjustment of a prism pair using an adjustment member to circularize in cross section a range of elliptical laser beam cross sections. A first prism rotates and translates towards or away from an incident laser beam while a second prism simultaneously rotates towards or away from the laser beam in a fixed counter-rotating relationship with the first prism. The degree of rotation and translation is determined by a mechanical linkage connecting the two prisms.

Abstract: This invention relates to a scattering transflector wherein the reflectivity of a surface of the transflector is dependent on the angle at which light is incident on the surface of the transflector. This invention also relates to a display device comprising an optical modulating element and the foregoing scattering transflector.

Abstract: An illumination optical apparatus successfully realizes mutually different illumination conditions in orthogonal two directions on an illumination objective plane. A magnification-varying optical system for similarly changing the entire size of a secondary multiple light source is arranged in an optical path between a first optical integrator for forming a first multiple light source on the basis of a light beam from a light source and a second optical integrator for forming the second multiple light source having light sources of a larger number on the basis of a light beam from the first multiple light source. The apparatus further comprises an aspect ratio-changing element for changing the aspect ratio of the incoming light beam in order to change the angle of incidence of the incoming light beam into the first optical integrator in a predetermined direction.

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

Abstract: A cross dichroic prism comprises four triangular prisms having isosceles right triangular cross sections identical in shape, opposing side faces thereof being bonded and secured together with rectangular portions thereof facing each other; and a dichroic film having an X-shaped cross section formed between the bonding faces of the triangular prisms; wherein, of the four triangular prisms, a given prism and at least one of the prisms adjacent thereto have a refractive index difference therebetween of 0.00005 or less, and the remaining two prisms opposed thereto have a refractive index difference therebetween of 0.00005 or less.

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

Abstract: An image display apparatus has a display device for displaying image information and an optical system for guiding light from the display device to the eye. The optical system has a prism body of a positive refractive power including three or more surfaces with refractive powers differing depending upon azimuthal angles. The surface of the prism body closest to the display device is a surface in which refractive powers thereof differ depending upon azimuthal angles and in which a local curvature radius area having a positive refractive power on a local generating-line section (meridional section) is interposed between local curvature radius areas having a negative refractive power on the local generating-line section (meridional section).

Abstract: Method and apparatus are disclosed for beam dividing and shaping, in which the beams from laser diode array are divided in a plurality of sections along the slow axis and the sections of beams are then recombined along their fast axis so that the Lagrange invariant of the resulting beam increased approximately by n-fold in fast axis and reduced approximately by n-fold in slow axis. With the inclusion of above apparatus in diode laser modules, the main objectives of constructing high-efficiency solid state lasers can be achieved.

Abstract: A packaged micromirror assembly (10; 110) is disclosed. The assembly (10) includes a micromirror (70) formed of a lower element (60) having a central mounting portion (63) surrounded by an intermediate gimbal portion (62) and a frame portion (61). A magnet standoff (68) is attached to the central mounting portion (63) and an upper mirror surface (65) is attached to the magnet standoff (68). The micromirror (70) may be packaged into a body (30) with coil drivers (36). A magnetic field generated by the coil drivers (36) applies a torque to the magnet standoff (68) causing it to rotate; because of silicon hinges in the lower element (60), the upper mirror (65) can rotate in two axes. An alternative embodiment of the assembly (110) rotates a lower mirror element (130) and an upper mirror (15) attached thereto by a standoff (68) by way of an electrostatic force.

Abstract: An optical film having structures that vary in height along their length where the variations have a nominal period of less than forty times the nominal height of the structures is taught. In some embodiments of the invention the variation is random.

Abstract: An optical turning film has a first surface including an array of prisms. The array has a plurality of first prisms, with each of the first prisms having a first prism configuration, and a plurality of second prisms, with each of the second prisms having a second prism configuration different from the first prism configuration. The optical film also has a second surface opposing the first surface, and light rays incident to the first surface are directed by the plurality of first prism and the plurality of second prisms along a direction substantially parallel to a viewing axis.

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

Abstract: A steerable optical arrangement. The inventive arrangement includes a first prism mounted for rotation about an optical axis and a second prism mounted for rotation about the optical axis. In accordance with the inventive teachings, the first prism and/or the second prism have at least one surface contoured to correct for optical aberration. In the illustrative embodiment, the first and second prisms are Risley prisms. In addition, the illustrative implementation includes a first motor arrangement for rotating the first prism about the optical axis and a second motor arrangement for rotating the second prism about the optical axis. A controller is provided for activating the first and second motors to steer the beam at an angle &phgr; and nod the beam at an angle &thgr;. At least two surfaces at least one prism is contoured to correct for astigmatism, coma, trefoil and other non-rotationally symmetric aberration.

Abstract: An optical device includes a substrate 60 and three prisms 10, 20 and 30. The first prism 10 is disposed adjacent to an upper surface of the substrate 60. An incoming beam aperture 65 is positioned adjacent a first surface 12 of the first prism 10, the first surface 12 extending away from the upper surface of the substrate 60. The second prism 30 is disposed adjacent to the upper surface of the substrate 60 and is spaced from the first prism 10 by a first distance. The third prism 20 is also disposed adjacent to the upper surface of the substrate 60. The third prism 20 may be spaced from the second prism 30 by the same first distance. An outgoing beam aperture 66 is positioned adjacent a first surface 22 of the third prism 20. The substrate 60 has phase changing reflective surfaces 40 and 50 along the upper surface between the first prism 10 and the second prism 30 and between the second prism 30 and the third prism 20.

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

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

Abstract: What is described here is a system for as well as a method of geometric beam shaping of the beam profile of a light beam, comprising a first prism and a second prism optically transparent to the light beam, which prisms are so disposed in the optical path of he light beam in such a way that after the passage of the light beam through both prisms the beam profile of the light beam may be expanded or reduced in a direction orthogonal on its direction of propagation by a first factor, and by a second factor different from the first factor in a direction orthogonal on the first direction.

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

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

Abstract: To effectively make a mesh of out lines between pixels by a pixel diffusion and at the same time to facilitate a focusing of an image by the observer, an optical filter for diffusing each pixel of a display device into a plurality of parts by utilizing diffraction or refraction is interposed between the display device having an image pattern in a mosaic form and an observer. The optical filter surface performs the pixel diffusion so that a sight angle, of a gap which does not pass light between the neighboring pixel after the pixel diffusion, as viewed from the observer on the focal plane on which the image displayed by the display device is observed by the predetermined observer is substantially a recognizable limit view angle of the observer.

Abstract: A microscope with incident light input coupling, wherein the light provided for the incident illumination is directed onto the partially reflecting layer of a beam splitter cube and is directed from there through the objective onto the specimen, while the light reflected and/or emitted by the specimen travels back to the partially reflecting layer and passes through the latter into the imaging beam path. In a microscope of this type, the beam splitter cube is provided with a negative spherical curvature at its outer surface facing the objective. Further, instead of the conventional tube lens, there is a combination formed of a converging lens and a diverging lens, wherein the surface curvatures of the converging lens and the diverging lens and the negative spherical curvature effected at the beam splitter cube are adapted to one another in such a way that the back-reflections of the incident illumination in the intermediate image plane are limited to a minimum.

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

Abstract: This invention relates to an optical apparatus for observation which is provided with drive control means for driving a variable angle prism on the basis of an output signal from vibration detecting means and in which the variable angle prism is installed between an objective lens and an erect prism.

Abstract: An angular positional data of binoculars in a lateral irection is calculated by integrating output of a gyro sensor. A positional data of correction lenses in the lateral direction is calculated by multiplying a driving step number of a rotor of a stepping motor which drives the correction lenses in the lateral direction, by a driving amount of the lens holding frame, which holds the correction lens, according to a one step rotation of the stepping motor. A difference between the angular positional data and the positional data of the correction lenses is calculated. If the difference is within a range from a positive threshold value to a negative threshold value, an electric power supply to a driving circuit of the stepping motor is stopped. With respect to a lengthwise direction, a similar operation to that of the lateral direction is performed.

Abstract: An asymmetric prism sheet, surface light source and LCD to which the asymmetric prism sheet is applied is provided. A cold cathode tube backed by a reflector supplies light to an incidence surface of a directional emission guide plate. A polarization separation sheet and a liquid crystal panel are disposed outside of the asymmetric prism sheet, with the reflector disposed along a back face. First and second slopes of each asymmetric prism element rows have inclination angles &phgr;a, &phgr;b which are selected as to allow a secondary ray to exist inside a main ray emitted from a frontal face in a manner such that the main ray is deflected toward a generally frontal direction by way of internal reflection of the second slope while the secondary ray is deflected toward a generally frontal direction by way of double internal reflection of the first and second slopes. An outer face provides an uneven face such as non-glare-processed face, orthogonal prismatic face or lens face.

Abstract: The present invention is related to a Wollaston prism (WP) comprising two birefringent wedges (W1, W2) joined by their hypotenuse to form a composite block, said wedges having optic axes (OA1, OA2) to each other at right angle. According to the invention, the optic axes (OA1, OA2) of said wedges (W1, W2) are rotated by an angle of 45° or 135°, respectively, with regard to a position wherein one of the optic axes (OA1, OA2) lies parallel to the plane formed by the hypotenuse. In an embodiment of the present invention, liquid crystal is used as material for the wedges (W1, W2) resulting in inexpensive and easy to handle Wollaston prisms.

Abstract: A beam shape compensation optical system includes a first anamorphic beam expander which expands a cross section of a parallel beam incident along a predetermined direction at a first magnification ratio M1 at least in a first direction which is perpendicular to the predetermined direction, and a second anamorphic beam expander which expands a cross section of a parallel beam incident along the predetermined direction at a second magnification ratio M2 at least in a second direction which is perpendicular to the predetermined direction. The first and second anamorphic beam expander are rotatable so that an angle between the first direction and the second direction on a plane perpendicular to the predetermined direction is changeable.

Abstract: Disclosed is a multi-beam optical system, which has a light source having a plurality of light emitting portions from which a plurality of light beams are emitted, respectively; a collimating lens which collimates the plurality of light beams into a plurality of parallel light beams; a beam shaping optical system including at least one wedge prism, the beam shaping optical system shaping cross section of the plurality of parallel beams; an image forming optical system which converges the plurality of parallel beams transmitted through the beam shaping optical system. In such a multi-beam optical system, a plurality of light emitting portions are aligned in a direction perpendicular to a principal section of the wedge prism.

Abstract: A compact optical system for microscope, endscope and binoculars capable of providing a clear image of minimal distortion even at a wide field angle. The optical system is a decentered optical system. Curved surfaces constituting the optical system include at least one rotationally asymmetric surface having no axis of rotational symmetry in or out of the surface. To correct rotationally asymmetric aberrations due to decentration by the rotationally asymmetric surface, the following condition is satisfied: −1000<FX/FXn<1000 where FX is the focal length in the X-direction of the optical system, and FXn is the focal length in the X-direction of a portion of the rotationally asymmetric surface on which an axial principal ray strikes.

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