Abstract: A polarizer having first and second reflecting surfaces which define an angle of 120.degree. therebetween and a beam splitting surface which lies in a bisectional plane of the first and second reflecting surfaces. The first and second reflecting surfaces and the polarization beam splitting surface are arranged to meet at a line which defines an edge of the polarizer.

Abstract: A light directing film including a first surface and a second structured surface. The structured surface includes a repeating pattern of prism zones including at least a first zone having a plurality of prism elements with peaks disposed at a first distance from a reference plane and a second zone having a plurality of prism elements with peaks disposed less than the first distance from a reference plane. The width of the first zone preferably measures less than about 300 microns.

Abstract: A lens-barrel optical system of the present invention is a lens-barrel optical system for guiding a beam emerging from an objective optical system in a focused state to an eyepiece optical system, which includes (i) a deflecting prism having three internal reflecting surfaces arranged in a triangular prism, the deflecting prism successively reflecting a beam incident in a first direction parallel to the optical axis of the objective optical system by the three reflecting surfaces to let the beam travel in a substantially M-shaped optical path, thereby letting the beam emerge in a second direction opposite to the first direction; and (ii) a reflector for reflecting the beam emerging from the deflecting prism to guide the beam to the eyepiece optical system.

Abstract: An optical system for a real image type view finder having an objective lens system and an ocular lens system, including a first deflector and a second deflector. The first deflector has a first reflection surface which reflects on-axis light, incident thereupon along an optical axis of the objective lens system, towards an optical axis of the ocular lens system. The second deflector has an incident surface upon which light, reflected by the first deflector, is made incident, and second and third reflection surface to internally reflect that light incident upon the incident surface, before emitting the light through an exit surface toward the ocular lens system. The on-axis light incident upon the first deflector and the light reflected by the first deflector defines an acute angle therebetween. The second deflector satisfies the following relationships:90.degree.<.theta.<120.degree.90.degree.<.psi.<120.degree.wherein ".theta.

Abstract: An achromatic polarization-rotating right-angle prism system for rotating the plane of polarization of an electric field, E, by 90.degree. while maintaining strict linear polarization at all wavelengths. The direction of travel of the beam may be altered by 90.degree. or the beam may continue on in the same direction and along the same line of travel. One embodiment includes two pairs of right-angle isosceles prisms. The horizontal, H, and vertical components, V, of E each undergo an equal number of s- and p-polarized reflections.

Abstract: A projection display comprising: a square column dichroic prism composed of four triangle prisms having equal refractive index together whose cross sections are right isosceles triangles such that three light valves are located adjacent to three exterior peripheral surfaces of dichroic prism to receive colored and modulated light beams therefrom and; a filter for absorbing light with a specified wavelength range, leaked from surface of dichroic prism at the opposite side of incident light surface and directed to liquid crystal light valve, the filter being located between liquid crystal light valves and surface of dichroic prism. As for construction of the dichroic prism itself, specifically, of the four aforementioned triangular prisms, the first triangular prism and the aforementioned third triangular prism are mutually affixed in a condition in which there is a first step difference in the vertical direction. The first exposed side is formed on one edge of the affixed side of the first triangular prism.

Abstract: A polarizing splitter device includes a double prism having an entry face for receiving a beam of unpolarized light, a polarizing splitter transmitting the polarized light in a first polarization direction, and reflecting the light polarized in a second polarization direction. The double prism also has a reflection face provided with a mirror receiving the light reflected by the polarizing splitter as well as an exit face for receiving and transmitting the light transmitted by the polarizing splitter and reflected by the mirror.

Abstract: An optical device comprising a glass prism that functions as a 180.degree. fold prism and a quarter-wave retarder. The optical device comprises a 180.degree. folding glass prism having first and second total internal reflecting surfaces that provides a 90.degree. phase shift of laser energy at a plurality of wavelengths propagating therethrough. The composition of the glass prism is selected so that its refractive index provides a 45.degree. shift at each of first and second total internal reflecting surfaces. Dispersion in the glass is chosen to be small enough so that the phase shift of the energy propagating therethrough is relatively insensitive to wavelength. Consequently, the prism also functions as a quarter-wave retarder at the plurality of wavelengths.

Abstract: An optical guide (10, 40, 50, 60) for horizontally aligning two vertically stacked images generated by one or two SLMs. The optical guide has a channel separator (10a) that directs both images along two different paths. A pair of aligning reflectors (10b and 10c) on each path vertically shift the images with respect to each other so that at least part of the images on the first path are aligned side-by-side with at least part of the images on the second path. The channel separator (10a) then re-directs the images to the image plane 15. Along both paths, at least two of the reflecting surfaces of channel separator (10a) or aligning reflectors (10b and 10c) are optically powered so as to change the width or height of the images.

Abstract: A beam shaper device for an optical read/write head on an optical disc drive is provided. This beam shaper device is particularly useful for shaping a laser beam originally emitted with an elliptical cross section, into having a substantially circular cross section. The beam shaper device includes only one prism and one plane mirror. The shape of the prism and the orientation of the plane mirror are specifically devised in such a way as to allow the output beam shaper device to have a circular cross section and to have its propagation axis orthogonal to that of the input laser beam.

Abstract: In detecting a focus error for an optical pickup, an inverse image generator for generating inverse images onto a light beam reflected from an optical disk is used in a focus error detecting method and apparatus thereof. The inverse image generator is composed of a semi-transmissive plane for splitting a light beam into first and second light beams, first and second prisms for inverting the phase of the second light beam, and third and fourth prisms for synthesizing the phase-inverted second light beam with the first light beam. Also, the inverse image generator has two quadrant wave plates, a polarization plane and light synthesizing plane for preventing a light loss. Since the errors due to an optical axis variation is eliminated from the focus error signal detected from the synthetic light beam radiated by the inverse generator, the optical pickup can be driven with stability.

Abstract: A multi-fold optical magnifier includes a prism with four reflecting surfaces positioned to direct light from an inlet to an outlet, and a lens positioned adjacent the prism outlet to receive light from the prism. An aspheric surface of the lens is in the light path for aberration correction and diffractive optical elements formed on the prism and lens are positioned in the light path to provide further aberration correction. The prism and lens angularly magnify an image source at the prism inlet by greater than ten. The total distance, orthogonal to the source plane, between the prism inlet and the lens outlet is 10 to 15 millimeters.

Abstract: An optical guide (10, 40, 50, 60) for horizontally aligning two vertically stacked images generated by one or two SLMs. The optical guide has a channel separator (10a) that directs both images along two different paths. A pair of aligning reflectors (10b and 10c) on each path vertically shift the images with respect to each other so that at least part of the images on the first path are aligned side-by-side with at least part of the images on the second path. The channel separator (10a) then redirects the images to the image plane 15. Along both paths, at least two of the reflecting surfaces of channel separator (10a) or aligning reflectors (10b and 10c) are optically powered so as to change the width or height of the images.

Abstract: Methods and apparatus for center masking a condenser lens of a transmitted light microscope to simultaneously maximize resolution, contrast and depth of field utilizing at a conjugate plane of the aperture plane where an image of the rear aperture of the condenser lens has been created, a plurality of light sources to illuminate two or more of the faces of a multi-face mirror in the shape of a pyramid which moves relative to the light sources to vary the amount of center masking continuously over a range including zero while directing multiple oblique beams of light onto the objective lens.

Abstract: A polarization converter P free from any particular limitation in the polarization direction of incident light or wavelength dependence, and large in the degree of freedom of selection of material is composed of polarization conversion unit P1, its united block, or combination or the like. P1 is composed of blocks of one body shape uniting three triangular columnar volume region elements having both ends in right-angled isosceles triangular form so that axial directions of triangular columns corresponding to the elements respectively may be directed in three mutually orthogonal directions. When a linear polarized light L enters vertically to surface 1a, its propagation route is in the sequence of incident point Q.fwdarw.total reflection point R1.fwdarw.total reflection point R2.fwdarw.total reflection point R3.fwdarw.exit point Q'. The incident ray L and exit ray L' are parallel to each other. The polarization direction is preserved at point R1, but is converted 90.degree.

Abstract: A double Porro prism having an incident surface, an exit surface, and a plurality of reflecting surfaces for internally reflecting light rays from the incident surface to the exit surface. The plurality of reflecting surfaces having a final reflecting surface that is positioned near the exit surface. The double Porro prism also has a ghost preventing surface that is formed between a ridge of the final reflecting surface and a ridge of the exit surface.

Abstract: A polarization plane rotator, for executing rotation of the plane of polarization of linearly polarized light that is incident thereon with a predetermined angle of incidence, is formed of a transparent prism or an array of such prisms, each prism having a triangular cross-sectional shape, with first, second and third surfaces having respective lines of intersection that are mutually parallel. The linearly polarized light is incident on the first surface, to be reflected twice in succession at the second and third surfaces, to be emitted from the first surface with the plane of polarization rotated by 90.degree. and the direction of propagation altered. An optical thin film is formed on the second and third surfaces, for substantially reducing an amount of phase difference between the P and S polarization components which results from reflection, thereby ensuring that the emitted light is substantially completely linearly polarized.

Abstract: An information indicator suitable for information processors such as personal computers, word processors and the like includes a light source, a scattering plate which scatters light from the light source, an indicator plate irradiated with scattered light from the scattering plate, and a prism plate operatively arranged with respect to the scattering plate and the indicator plate and having a prism-like protuberance structure formed at a side thereof. The prism plate is so disposed that the prism-like protuberance structure faces the scattering plate, and the angle 2.theta. constituting the prism-like protuberance structure is defined by the formula, 2.theta..ltoreq.2/3.times.(.pi./2+2.times.arcsin (n'/n)), in this inequality, n is the refractive index of said prism plate medium, and n' is the refractive index of a material in which the prism plate is arranged.

Abstract: An image projection system wherein light provided from a source passes through a prism and is then incident on an array of reflecting elements which are individually adjustable between a first and second position. Light reflected from each element re-enters the prism. Light from elements in the first position pass through the prism and into a lens. Light from elements in the second position travel through the prism, but do not enter the lens. The principal plane of the lens and the plane in which the elements are located are each parallel to the adjacent surface of the prism.

Abstract: To increase the measuring sensitivity of a simple-to-manufacture, multi-faced solid optical current sensor, at least one of the light-reflecting lateral faces is displaced radially inward with respect to the remaining light-reflecting lateral faces and has a lesser minimum distance from a center of the solid optical current sensor than the other lateral faces. Because of this displacement, the incident light beam does not move through a closed polygonal progression in the course of a single circuit around a recess for a current conductor, whose current intensity is to be measured by means of the Faraday effect. Helically overlapping displacements of the light circuit paths are created, which cause an increase in light sensitivity. The lateral face or another lateral face can also be displaced outwardly instead of inwardly.

Abstract: An optical guide for horizontally aligning two vertically stacked images generated by one or two SLMs. The optical guide has a channel separator that directs both images along two different paths. A pair of aligning reflectors on each path vertically shift the images with respect to each other so that at least part of the images on the first path are aligned side-by-side with at least part of the images on the second path. The channel separator then redirects the images to the image plane. Along both paths, at least two of the reflecting surfaces of channel separator or aligning reflectors are optically powered so as to change the width or height of the images.

Abstract: A rotatable polygon mirror comprising a transparent regular polygonal cylinder having the sides of a regular polygon. The sides are rotationally symmetrical with one another relative to a rotating axis of the transparent regular polygonal cylinder. The transparent regular polygonal cylinder has inner surfaces in the body of the transparent regular polygonal cylinder which correspond to the respective sides of the regular polygon, where the inner surfaces consist of total internal reflection surfaces.

Abstract: An optical beamsplitter comprises a right angle prism having a hypotenuse and two legs wherein the hypotenuse includes an optically selective coating deposited thereon. An optical element is positioned adjacent the hypotenuse such that the hypotenuse and the optical element form a beamsplitting interface. Various optical elements are utilized to achieve the desired spatial and angular relationships between incoming and outgoing light beams. Several embodiments are disclosed wherein the optical element can comprise a flat plate for providing spatial offset, a wedged plate for producing spatial and angular offset, a lens for adding optical power, or a faceted thin plate.

Abstract: A lens assembly is positioned between an illuminated scanning area and a detector. A multiple reflecting assembly positioned between the lens assembly and the illuminated scanning area defines a folded light path between the lens assembly and the illuminated scanning area. A prismic reflecting assembly is movably mounted between the lens assembly and the multiple reflecting assembly, so that the length and direction of the folded light path can be changed by moving the prismic reflecting assembly to align and focus the image of the illuminated scanning area on the surface of the detector.

Abstract: Disclosed is a projection system wherein light provided from a source passes through a prism and is then incident on an array of reflecting elements which are individually adjustable between a first and second position. Light reflected from each element re-enters the prism. Light from elements in the first position pass through the prism and into a lens. Light from elements in the second position travel through the prism, but do not enter the lens. The principal plane of the lens and the plane in which the elements are located are each parallel to the adjacent surface of the prism.

Abstract: A compound type cone mirror installed inside a sonde moving up and down in a borehole for observing the whole circumference of the hole wall at an arbitrary depth at a time, a combined mirror for locally observing the hole wall in detail, and an elevating sonde equipped with these mirrors are provided for observing the wall surface of a borehole In the ground. In the compound type cone mirror, a transparent truncated cone block the surface of which is finished by polishing is inserted into a concave portion or pierced hole having the same shape as said truncated cone block and formed coaxially in the axial direction in a transparent column block the surface of which is finished by polishing, and said inserting face is a mirror finished face. Moreover, in the combined mirror, a plane mirror slanted upward at 45.degree. to the axial direction is mounted onto the top face of the truncated cone block or column block of the compound type cone mirror.

Abstract: An optical device having a transparent body and including two prism surfaces formed thereon. The composite structure exhibits two axis stability in that the angular relationship between the input beam and the output beam remains fixed for slight movement of the device about two orthogonal axes.

Abstract: An information indicator suitable for information processors such as personal computers, word processors and the like includes a light source, a scattering plate which scatters light from the light source, an indicator plate irradiated with scattered light from the scattering plate, and a prism plate operatively arranged with respect to the scattering plate and the indicator plate and having a prism-like protuberance structure formed at a side thereof. The prism plate is so disposed that the prism-like protuberance structure faces the scattering plate, and the angle 2.theta. constituting the prism-like protuberance structure is defined by the formula, 2.theta.>2/3.times.(.pi./2+2.times.arcsin (n'/n)), in this inequality, n is the refractive index of said prism plate medium, and n' is the refractive index of a material in which the prism plate is arranged.

Abstract: An all-directional optical sensor apparatus 8 includes an all-directional prism 20 which has a cylindrical-shaped body with a hollow-out cone section formed in its top surface 22. The surface 28 of the cone works as a reflector 30 for rays received through side surfaces 24 of the cylindrical-shaped body. An optical sensing element is disposed adjacent to a bottom surface 26 of the prism 20. A roof plate 40 having a dimension larger than the top surface 22 of the prism is arranged for shielding the entry of any light other than an input signal into an upper portion of the prism 20.

Abstract: A rotary mirror system for angularly deflecting a light beam including an air bearing arrangement rotatably supporting a mirror body on which one or more mirror facets are provided, the mirror body being the rotor of an electric motor, wherein the mirror facets are the side surfaces of an internal pyramid or frusto-pyramid formed in and opening towards one axial end surface of the mirror body and having an axis of symmetry coinciding with the rotational axis (A) of the mirror body, the orientation of the mirror facets, relative to the incoming light beam, being such that the reflected beam leaves the internal pyramid at an inclined angle with respect to the rotational axis (A).

Abstract: An endoscope includes a disposable probe and a non-disposable focusing ocular. The probe includes a transfer module assembly including one or more relay modules, and an objective element including a distal glass window, a molded plastic prism and three molded plastic lenses. Each of the relay modules contains an entry glass rod, an intermediate glass rod, and an exit rod, each having flat end surfaces and two identical molded plastic doublets. The elements of the ocular are all of glass and include an axially movable focusing doublet and two non-movable doublets. The disposable probe introduces certain aberrations into the image. The non-disposable focusing ocular corrects these aberrations. A single curved surface is formed on the distal glass window of the probe; all other curved optical surfaces of the disposable probe are formed on molded plastic members, thereby reducing the cost of the probe sufficiently to be cost-effective for single patient, disposable use.

Abstract: A compound prism including a plurality of unit prisms which have reflective interfaces defined by outer and/or inner surfaces thereof and which are arranged so that light is reflected by an inner surface of the interface of one of the unit prisms and by an outer surface of the interface of another unit prism.

Abstract: An optical novelty device comprising a pair of wedge prisms disposed in a container having a viewing port and a light-entry port whereby an image viewed through said device appears as a symmetrical right-side-up refracted image regardless of the orientation of the device

Abstract: An optical low pass filter including a phase grating for obtaining useful picture image characteristics by provision of preferable low pass effects for each of wave form zones about the spatial frequency components beyond Nyquist limit which are required to be removed as the picture images are discretely sampled in nature in an optical system of a single tube color television camera having a color separating filter, a color video camera using solid state imaging elements, and so on, which is easier in construction to be constructed.

Abstract: An apparatus for deflecting an optical beam is designed as a prism and has an entry face as well as two reflection faces and two exit faces. The prism is essentially symmetrically constructed with reference to a rotational axis. The entry face is oriented essentially perpendicularly relative to the rotational axis. Those sides of the prism facing away from the entry face are designed as reflection faces having an inclination relative to the rotational axis, these reflection faces adjoining one another in the region of the rotational axis. Those sides of the prism facing away from the rotational axis are designed as exit faces which adjoin the entry face and the respective reflection face and, proceeding from the entry face, extend with increasing distance from the rotational axis.

Abstract: The invention relates to an optical device which serves in particular for measuring the speed of a moved surface with the aid of a measuring beam from a laser. The measuring beam is split into two parts, directed through prisms to converge towards the moved surface and received again frequency-shifted by the Doppler effect. For each part beam there is a single prism body through which each part beam is guided outwards to intensify splitting and is deflected to bring about convergence. Each prism is preferably secured to a plane-parallel glass plate so that very good, lasting adjustment is possible.

Abstract: An apparatus for aligning a laser leveling instrument along a building line can remain standing unchanged on its base throughout both horizontal and vertical leveling operations. The light source is located in the base of the instrument. The instrument head can be swung through 90.degree. and houses a rotating prism which generates the vertical plane, and an adaptor. The adaptor includes a prism for deflecting the light from the source into the rotating prism and a triple prism which, when brought into the light path, deflects the light coming from the base perpendicular to the generated vertical plane, projecting it onto the building line.

Abstract: A pupil/image reversal prism (FIG. 2) forms a pupil at an image location. Such a prism has specific applicability in a DCR scheme for a thermal imaging system (FIG. 3a, 31 and 32) in which a passive DCR source is implemented by a pupil imager that forms a pupil onto the image of a thermal scene, thereby providing scene-average radiation to a thermal detector array. The pupil/image reversal prism including an input reflective surface (A), an output reflective surface (B) , a positive reflective surface (C) and an intermediate folding reflective surface (D). The reflective surfaces A and B use total internal reflection to provide both transmissive and reflective operation.

Abstract: A projection unit for a car head-up display comprises a display source, a curved mirror which provides the optical power of the projection unit and, in use, receives light from the display source, and a Fresnel mirror extending generally between the display source and the curved mirror and disposed to receive reflected light from the curved mirror and to reflect that light in a desired direction. The curved mirror and the Fresnel mirror may be disposed on a solid block of transparent material having one curved end coated to provide the curved mirror, the display source being located at an opposite end of the block, and the Fresnel mirror being formed in a block face extending from the opposite end of the block to the curved end of the block.

Abstract: An optical system is described for combining separate deformable mirror device images into a single image. The resulting image is a single continuous image comprising left and right halves corresponding to the original individual images. The system is particularly useful for presenting spatial light modulator images to the printing drum of a xerographic process for letter quality documents. The combined image width allows a substantially greater printing width than was previously possible.

Abstract: The invention provides an achromatic expansion prism for use in magneto-optical disk drive systems. The achromatic expansion prism comprises a first prism having a first dispersion value, an entrance surface through which a light beam enters the first prism and an outlet surface through which the light beam exits the first prism, and a constant deviation prism fixed to the outlet surface of the first prism and having a second dispersion value. The constant deviation prism reflects the light beam in a first direction to the optical disk and reflects the light beam reflected from the optical disk in a second direction to a detector. The angle between the first and the second directions is constant irrespective of the angle of incidence of the light beam on the first prism. Moreover, the first and second dispersion values are selected such that the first and second directions are independent of wavelength of the light beam.

Abstract: An image recognition apparatus comprises a support for placing thereon an inspection object, an impage pickup unit spaced from the support for detecting an image of the inspection object, and an image alternating unit arranged in an optical path extending between the support and the image pickup unit. The image alternating unit includes a quadratic prism which has a longitudinal axis substantially in parallel to the support, and the quadratic prism has two incident surfaces directed toward the support and two exit surfaces directed away from the support.

Abstract: A wide field-of-view optical element 12 suitable for use in a laser warning system including a frusto-conical block of optically transparent material having a first surface 14 and a second surface 16. The first surface 14 is parallel with the second surface 16 and coaxial therewith. The radius R.sub.1 of the first surface 14 is less than the radius R.sub.2 of the second surface such that the sides of the element 12 are slanted. Reflective material is coated on the interior 17 of the first surface 14 for directing incident optical energy toward a detector 20 mounted at the second surface 16. Similarly, a reflective material is coated on the interior 18 of the second surface 16 for directing incident optical energy to the detector 20 via the first surface 14. The second reflective coating on the second surface is disposed between the outer periphery thereof and a nonzero distance R.sub.3 from the center thereof to provide an aperture at which the detector 20 may be mounted.

Abstract: A focus detecting optical system comprises two imaging optical systems which are composed of an integrally molded prism, and is adapted to perform focus detection on the basis of relative positional relationship between an image of an object formed with one of the imaging optical systems and another image of the object formed with the other imaging optical system. Ineffective optical path regions of the surfaces of the prism which allow transmission or reflection of the rays entering the prism are designed as light diffusing surfaces and/or surfaces coated with a light absorption substance. An aperture stop arranged before each surface of incidence of light is arranged eccentrically with regard to the optical axis of incident rays or each surface of incidence of light has a refractive power asymmetrical with regard to said optical axis so that all the rays incident on the totally reflecting surfaces arranged in the two imaging optical systems are totally reflected.

Abstract: An optical low-pass filter comprising at least two boundary surfaces arranged substantially parallel to each other which can split incident light into two components or reflect it and at least one of which has color dependency, in order to make it possible to be favorably used to an objective optical system for for endoscopes, to have wavelength dependency to response, and to minimize the generation of color moire. The optical low-pass filter is constructed in the form of various shaped prisms and can also have two-dimensional filter characteristics.

Abstract: A compound prism including a plurality of unit prisms which have reflective interfaces defined by outer and/or inner surfaces thereof and which are arranged so that light is reflected by an inner surface of the interface of one of the unit prisms and by an outer surface of the interface of another unit prism.

Abstract: A mount for use by optical elements in a laser tooling alignment system. The mount provides a high degree of isolation from external rotational disturbances about any horizontal axis (i.e., pitch and roll) by retaining optical components in a fixed relationship to the local gravity gradient. The mount is a passive gravity referencing two stage, fluid damped pendulum. When a constant deviation optic (e.g. pentaprism beam splitter) is attached to the mount, effective isolation from yaw disturbances is also achieved.

Abstract: An assembly for rotating an image formed by a group of light rays has a first prism with a transparent first facet through which the light rays enter. The image light rays entering the first facet strike a second facet at angles of incidence greater than the critical angle and are reflected toward a third facet. The third facet is silvered to reflect substantially all of the image light rays back toward the second facet so that the light rays strike the second facet at less than the critical angle and exit the first prism. A second prism is spaced from the first prism to receive light rays from second facet. After entering the second prism, such light rays strike one of its facets and are reflected toward and through an exit facet. The facets of the second prism are angled to minimize image distortion and compensate for lateral offset of the light rays exiting the assembly. A version of the assembly is described in which the second prism is replaced by a mirror.

Abstract: An optical system for use in conjunction with a one or two dimensional array of high brightness sources where such sources are individually rotated by multiple reflective elements and in turn may be captured by beam filling optics and subsequently re-imaged by symmetric and asymmetric optics where the asymmetric optics preferentially image a single dimension while leaving the focus in the second dimension largely unaffected. In this manner and by properly selecting the spacing as well as the width of the line sources, and by properly designing the symmetric and asymmetric optics, the array of high brightness sources can be reformatted in a brightness conserving manner that allows the reformatted beam to simultaneously have an arbitrary ratio of image length to image width and arbitrary divergences in the respective dimensions.

Abstract: A light beam scanner comprises a light beam generating unit for generating a light beam, a first scanning unit for guiding the light beam in a first scanning direction, a second scanning unit composed of a deflection prism for guiding the light beam in a second scanning direction that is different from the first scanning direction, and an object lens. The second scanning unit is movable in an optical direction in parallel with an optical axis or turnable around the optical axis, so that the light beam entering the second scanning unit may be deflected in any direction when exiting from the second scanning unit.