Abstract: An optical device for making light converge produces a convergent light beam with a satisfactorily great numerical aperture and acceptably small aberrations. The optical device has a plurality of diffraction gratings that each make light converge. The light shone into the optical device is passed through one after another of those diffraction gratings in such a way that the light is made to converge to a higher degree every time it passes through one of the diffraction gratings. The diffraction gratings may be all transmissive, all reflective, or a combination of both. The diffraction gratings are formed on a surface of or at an interface inside the optical device, and two diffraction gratings may be formed on a single surface. The light is made to eventually converge on the exit surface of the optical device so that the optical device functions as a solid immersion device.

Abstract: An optical module has a substrate, a waveguide, formed on the substrate, for guiding light, and a photonic crystal portion that has media having different refractive indices arranged in a periodic pattern and that is disposed in a channel of the waveguide on the substrate. Here, the photonic crystal and the substrate are integrally formed. The formation comprises the steps of forming an aluminum film on the top of a conductive substrate, forming a protective film on the aluminum film, removing the protective film from a predetermined area to form a window over the predetermined area, anodizing the aluminum film exposed through the window to form photonic crystals, removing the protective film, cladding the bottom of the substrate and forming a core layer over the cladded bottom.

Abstract: An improved optical scanning apparatus is adapted to be such that at either end of the scan range, an optical beam deflected by a reflecting surface of a scanner will pass through an anamorphic lens in scanning optics at a position spaced from its optical axis in the sub-scanning direction. The anamorphic lens has such a sectional profile in the sub-scanning direction that the lens thickness at one end of the sub-scanning direction differs from the thickness at the other end. Also, a high speed optical scanning apparatus based on the dual incidence and the oblique incidence, can prevent a positional variation of a scanning line that is due to a shift of each facet of the rotating polygonal mirror, which is caused by an offset of the rotating axis of the rotating polygonal mirror.

Abstract: A polarization conversion optical system converts light having a nonuniform plane of polarization into light having a uniform plane of polarization. The system includes a multilayer dielectric film at the side upon which the target light is incident. The film exhibits the property that it reflects one polarized component of the light and transmits a second polarized component of the light at a first angle of incidence, but transmits the first component at a second angle of incidence. Incident target light that is transmitted through the film at the first angle of incidence passes through a quarter-wavelength plate and is reflected at the second angle, whereupon it is retransmitted through the quarter-wavelength plate to be converted from one plane of polarization to the other. It is then emitted from the dielectric film in the same plane of polarization as light reflected by the film.

Abstract: A diffractive optical element has a diffraction grating formed by periodic depressions and projections on the surface of a substrate and a dielectric multilayer film on the diffraction grating. The materials of the respective layers of the film are chosen such that the depth of the depressions is an integral multiple of the sum of the thickness of the layers in one period of the film. As a result, individual layers of the film are continuous across multiple depressions and projections, to provide improved first-order reflectance.

Abstract: An optical scanner having a simple structure in which the light quantities of a plurality of light beams are not varied by differences in polarization direction among the light beams. The optical scanner scans a surface by means of a plurality of light beams in which the polarization direction of at least one of the light beams is different from the polarization directions of the other light beams. An optical element having a surface with a reflectance for s-polarized light and a reflectance for p-polarized light that are substantially the same at a given incident angle is provided in the optical paths of the light beams.

Abstract: An image forming apparatus includes a laser beam scanning unit adapted for scanning laser beams on a surface of a charged image bearing member (5). The laser beam scanning unit (53) comprises a semiconductor laser array (21) having a plurality of light emitting portions (21a) and a rotating polygon mirror adapted for deflecting laser beams emitted from the light emitting portions to the image bearing member (5). The light emitting portions (21a) are disposed two-dimensionally on a surface of the semiconductor laser array. The lighting and the amount of light of the light emitting portions (21a) are discretely controlled by a control unit. The scanning unit further includes a collimator lens having a focal length fc, where a distance between a most spaced two of the plurality of light emitting portions is .delta. max, and fc/.delta. max is 25 or more.

Abstract: A photonic crystal device including a method of forming the photonic crystal device is provided wherein the photonic crystal device comprises a first medium having a thickness and periodically defining a plurality of periodically spaced concave portions. The concave portions having a depth less than the thickness of the first medium. A second medium fills the concave portions. One layer of the device, including both the first and second medium, acts as an optical waveguide layer, or photonic crystal. Another layer is at least partially formed from the first medium, such that the first and second layers share a common medium. A method of forming the photonic crystal device including the steps of applying a resist layer to a first medium, removing portions of the resist layer and corresponding portions of the first medium to form vacancies, and filling the vacancies with a second medium.

Abstract: On a waveguide 34 formed on a substrate 33, a plurality of comblike shaped electrodes 37, 38 that generate surface acoustic waves 37a, 38a from different directions are provided. And a periodic refractive indices portion 40 is formed, where the refractive indices are periodically distributed in accordance with the wavelengths of the surface acoustic waves 37a, 38a generated by applying a voltage to the comblike shaped electrodes 37, 38. And by changing a frequency of the applying voltage for sequentially changing the wavelengths of the surface acoustic waves 37a, 38a, the exiting direction of the light exiting from the periodic refractive indices portion 40 is scanned. This makes it possible to provide an optical functional device and an optical scanning apparatus that perform light scanning less costly but at a high speed, and that can secure a wide scanning angle.

Abstract: An improved optical scanning apparatus is adapted to be such that at either end of the scan range, an optical beam deflected by a reflecting surface of a scanner will pass through an anamorphic lens 13 in scanning optics at a position spaced from its optical axis in the sub-scanning direction. The anamorphic lens has such a sectional profile in the sub-scanning direction that the lens thickness at one end of the sub-scanning direction differs from the thickness at the other end. Also, a high speed optical scanning apparatus based on the dual incidence and the oblique incidence, can prevent a positional variation of a scanning line that is due to a shift of each facet of the rotating polygonal mirror, which is caused by an offset of the rotating axis of the rotating polygonal mirror.

Abstract: An optical module has a substrate, a waveguide, formed on the substrate, for guiding light, and a photonic crystal portion that has media having different refractive indices arranged in a periodic pattern and that is disposed in a channel of the waveguide on the substrate. Here, the photonic crystal and the substrate are integrally formed.

Abstract: To provide an optical scanner for typical use with laser beam printers that is capable of effective correction of aberrational characteristics and which also produces a constant beam spot size, a semiconductor laser array 1 having a plurality of light-emitting portions issues a plurality of beams, which are reflected and deflected by reflecting surfaces of rotating polygonal mirror 5 and pass through imaging lens 6 to form a plurality of beam spots on the surface to be scanned 7. Both the entrance and exit surfaces of imaging lens 6 are such that the curvatures in the sub- and main scanning directions are independent of each other, with the curvature in the sub-scanning direction varying continuously in the main scanning direction over the effective area of imaging lens 6.

Abstract: An optical scanner that has a simple construction and which yet exhibits satisfactory imaging performance under varying temperature conditions. Of the two orthogonal scanning cross sections of scanning optics (i.e., the main and sub-scanning cross sections), the one that involves the greater movement of the image plane due to the temperature-dependent changes in optical characteristics (e.g. the variation in the operating wavelength of a light source, the index variation of a lens material and the thermal expansion of a lens itself) is adapted to be the same as the other cross section that involves the greater movement of the image plane due to the change in the distance from the light source to a collimator lens.

Abstract: A laser beam scanning unit (53) adapted for scanning laser beams on a surface of a charged image bearing member (5) is provided. The laser beam scanning apparatus (53) comprises a semiconductor laser array (21) having a plurality of light emitting portions (21a) and a rotating polygon mirror (3) adapted for deflecting laser beams emitted from the light emitting portions to the image bearing member (5). The light emitting portions (21a) are disposed two-dimensionally on a surface of the semiconductor laser array. The lighting and the amount of light of the light emitting portions (21a) are discretely controlled by a control unit (60).

Abstract: An optical scanner for use in laser beam printers and the like which is particularly satisfactory in imaging characteristics. A light beam from a semiconductor laser passes through a collimator lens, an aperture diaphragm and a cylindrical lens. The beam is then deflected by a rotating lens mirror and subjected to the focusing action of an imaging lens so that it is focused to form a beam spot, which scans over a scan surface as the beam is deflected. The imaging lens has aspheric surfaces in the main-scanning cross section and is designed so that the rate of change in its curvature and other relevant parameters satisfy a predetermined equation so as to lie within a predetermined range.

Abstract: The improved beam scanning apparatus has an optical element that is driven to rotate by means of a drive means so as to be capable of continuous angular displacement with respect to the beam from a light source. The optical element deflects the incident beam so that it is focused to form image on the image plane. It is provided with an entrance face, a reflecting face and an exit face which have their shape specified in such a way as to achieve effective correction of aberration, provide higher resolution, and reduce the size and cost of the apparatus.

Abstract: An optical scanner comprises: a light source; beam shaping optics for transforming an optical beam from the light source into a convergent beam; a rotating polygonal mirror having at least a first reflecting face for deflecting the convergent beam and a second reflecting face; and transmission optics having a lens, with which the optical beam deflected by the first reflecting face of the rotating polygonal mirror is allowed to be incident on the second reflecting face of the rotating polygonal mirror, with the optical beam incident on the second reflecting face of the rotating polygonal mirror being deflected therefrom to produce a scanning optical beam which scans a predetermined surface to be scanned, wherein the convergent optical beam forms a focused image at a point located between the first reflecting face of the rotating polygonal mirror and the lens in the transmission optics.

Abstract: An optical scanner that has a simple construction and which yet exhibits satisfactory imaging performance under varying temperature conditions. Of the two orthogonal scanning cross sections of scanning optics (i.e., the main and sub-scanning cross sections), the one that involves the greater movement of the image plane due to the temperature-dependent changes in optical characteristics (e.g. the variation in the operating wavelength of a light source, the index variation of a lens material and the thermal expansion of a lens itself) is adapted to be the same as the other cross section that involves the greater movement of the image plane due to the change in the distance from the light source to a collimator lens.

Abstract: An optical scanner that has a simple construction and which yet exhibits satisfactory imaging performance under varying temperature conditions. Of the two orthogonal scanning cross sections of scanning optics (i.e., the main and sub-scanning cross sections), the one that involves the greater movement of the image plane due to the temperature-dependent changes in optical characteristics (e.g. the variation in the operating wavelength of a light source, the index variation of a lens material and the thermal expansion of a lens itself) is adapted to be the same as the other cross section that involves the greater movement of the image plane due to the change in the distance from the light source to a collimator lens.

Abstract: An image forming apparatus including an image bearing member, a charging unit, a laser beam scanning apparatus and a developing unit. The laser beam scanning apparatus includes a semiconductor laser array for emitting laser beams, a collimator lens for collimating the beams, a rotating polygon mirror for deflecting the beams collimated by the lens, and an aperture stop between the laser array and the mirror. The following relations between the aforementioned elements of the apparatus are satisfied: ##EQU1## where f is a focal length of the collimator lens; s is a distance between a focal point on a mirror side of the collimator lens and the aperture stop; t is a distance between one of the light emitting portions that is spaced farthest, relative to others of the light emitting portions, from the optical axis; D is a diameter of the aperture stop, and d is a diameter of each of the laser beams collimated by the collimator lens.