Abstract: An optical information reading apparatus includes a semiconductor laser, a beam splitter, a collimating lens, a super-resolution cut-off filter, an objective lens having a high numerical aperture, and a photodetector. The super-resolution cut-off filter is disposed immediately in front of the incident side of the objective lens. The photodetector is a well-known eight-division photodetector with a signal processing circuit, reads recorded information and also outputs tracking and focusing control signals to a control circuit. The laser beam is separated into a 0-th order laser beam and ±primary laser beams, which are made incident on the objective lens, pass therethrough, and are made incident on the recording surface of a disk. The 0-th order laser beam is used to read information and to control focussing while the ±primary laser beams are used to control tracking.

Abstract: A spread illuminating apparatus combined with a liquid crystal display via a frame has a reduced thickness as a whole, thereby realizing a natural liquid crystal display image. A light conductive plate has its peripheral portion fitted in a groove of the frame, and a lamp disposed on a side surface of the light conductive plate is housed in the frame. A top side portion of the liquid crystal display is fitted into a cut-away portion of the frame by a predetermined dimension, and a space between a bottom surface of the light conductive plate and a top surface of the liquid crystal display is reduced, whereby the thickness of the entire apparatus is reduced by a dimension of the liquid crystal display fitted into the frame compared with that of the conventional configuration in which the frame is superimposed on the top surface of the liquid crystal display.

Abstract: A liquid crystal element is provided as a polarization plane rotating means between a laser beam source and a beam splitter. Light emitted from the laser beam source passes through the liquid crystal element and the beam splitter, and is converted into parallel light by a collimating lens. The collimated light is incident on a first light-selection means, is reflected at a flat first reflecting surface or a concave second reflecting surface, and is then incident on a super-resolution cut-off filter as a second light-selection means. The light having passed through the second light-selection means is incident on an objective lens, and is converged onto a recording surface. The selection of the reflecting surface of the first light-selection means is determined based on an operation mode of the liquid crystal element.

Abstract: There is provided a spread illuminating apparatus to suppress leakage of light. Light emitted from a light source, reaching a first inclined surface of grooves of a light reflection pattern and exiting out there is caught by a second inclined surface thereof at an area positioned above the first inclined surface since the distance between an upper edge of the second inclined surface and the level of a bottom thereof is set greater than the distance between an upper edge of the first inclined surface and the level of the bottom thereof. Thus, light, which will leak in case of a conventional art, can reenter a transparent substrate at the second inclined surface so as to improve illumination efficiency.

Abstract: There is provided a spread illuminating apparatus aiming to minimize the coverage of a liquid crystal screen while securely integrating a light conductive member with a transparent substrate. The light conductive member is wedge-shaped in which the width thereof is in inverse proportion to the increase in distance from a spot-like light source opposing face, and the transparent substrate is trapezoid-shaped in which a side aligned to the spot-like light source opposing face is shorter. A frame and transparent substrate overlapping part becomes larger from one side part to the other side part of the transparent substrate. Since the frame and transparent substrate overlapping part are large enough regardless of the small width of the frame than that of the prior art, the region of a liquid crystal screen can be increased accordingly.

Abstract: An information reading and recording apparatus in which recording media having respective recording densities different front each other, such as DVD, CD, CD-R/RW and the like, can be compatibly read and recorded only with a low-cost laser diode for low recording density. A laser beam from the laser diode is passed through a collimator lens via a half mirror, and there is provided a reflecting mirror for introducing the laser beam to one of two objective lenses, from which the laser beam is emitted towards the disk. One of the objective lenses is a lens having a high numerical aperture and the other one is a lens having a low numerical aperture. A super-resolution cut-off filter is disposed immediately before the objective lens having a high numerical aperture so that the objective lens and the super-resolution cut-off filter are placed in the optical path on reading DVD. On reading CD, the other lens is placed in the optical path.

Abstract: There is provided a spread illuminating apparatus to suppress the appearance of moiré fringes. A light reflection pattern of a transparent substrate is composed of grooves of substantially triangular in section and flat portions adjacent thereto. The light reflection pattern is formed substantially parallel to the optical axis of a bar-like light source and the depth of the grooves increases gradually in proportion to the increase in distance from the light source. The interval of the adjacent grooves (the groove interval) is set to vary irregularly. Thereby, the relation between the interval of grooves and the interval of mosaic pattern of liquid crystal cells is not definite, and the appearance of moiré pattern can be suppressed.

Abstract: There is provided a spread illuminating apparatus realizing both uniform light emission and high brightness. Two bar-like light conductive members made of a transparent material and each having a spot-like light source disposed on a large end thereof are disposed so as to overlap with each other in the thickness direction of a transparent substrate, thereby constituting a pair of bar-like light sources. Light emitted from the spot-like light source and entering one light conductive member of the two is directly guided into the transparent substrate without passing through the other light conductive member. Thus, light rays emitted from the two light conductive members do not interfere with each other so as to prevent generation of interference fringes, resulting in that uniform light emission and high brightness in the spread illuminating apparatus can be realized.

Abstract: There is provided a spread illuminating apparatus in which a bar-like light source radiates light more uniformly. Light scattering portions are formed to be inclined in a longitudinal direction of a light conductive member such that irradiation ranges of adjacent light scattering portions overlap partially with each other in the longitudinal direction of the light conductive member. Light ranges (La1 La2, La3, La4 and La5) in a longitudinal direction of the light conductive member per beam of light reflected at the light scattering portions and entering a transparent substrate are expanded so as to overlap partially with each other. Accordingly, the light conductive member includes no part that the light reflected at an optical path conversion means of the light conductive member does not cover in the longitudinal direction of the light conductive member. Thus, the light conductive member constitutes a light source that spreads uninterrupted linear light even on a microscopic level.

Abstract: A magnetic head exhibits a good traceability without giving damages to itself and a magnetic disk. In the magnetic head including a slider which comprises a plurality of magnetic cores having respective operating gaps for a standard recording density and a high recording density and an outrigger having a plurality of substantially rectangular slots for inserting the respective magnetic cores in, and slides against a magnetic recording medium, and in which one magnetic core for a high recording density having a spacer superposed thereon is inserted in one of the slots in such a manner as to touch a wall of the slot, the slider includes a rail surface which has a groove passing longitudinally through the spacer substantially at the center of its thickness and reaching both lengthwise ends of the slider, and which slides against the magnetic recording medium.

Abstract: A spread illuminating apparatus provides a uniform illuminance, an accurate illumination, an improved visibility, and an expanded screen size. Light sources (5a, 5b) comprising bar-like light conductive members (3a, 3b) and spot-like light sources (4a, 4b), respectively, are disposed close to end surfaces (8a, 8b) of a transparent substrate (2). A light reflection pattern (29) is formed on a surface of the transparent substrate (2) along the length of the light conductive members (3a, 3b). The light reflection pattern (29) comprises grooves (27) and flat portions (28) adjacent to the grooves. The grooves (27) are shaped trapezoidal in section, and the depth thereof increases in proportion to the increase in distance from the light sources (5a, 5b) and measures maximum at the center of the transparent substrate (2).

Abstract: There is provided a spread illuminating apparatus to suppress leakage of light. Light emitted from a light source, reaching a first inclined surface of grooves of a light reflection pattern and exiting out there is caught by a second inclined surface thereof at an area positioned above the first inclined surface since the distance between an upper edge of the second inclined surface and the level of a bottom thereof is set greater than the distance between an upper edge of the first inclined surface and the level of the bottom thereof. Thus, light, which will leak in case of a conventional art, can reenter a transparent substrate at the second inclined surface so as to improve illumination efficiency.

Abstract: There is provided a spread illuminating apparatus for improving the machinability and durability of a molding die for a transparent substrate and obtaining an excellent light reflection. In a light reflection pattern comprising grooves and substantially flat portions adjacent to the grooves and formed on an upper surface of the transparent substrate in parallel to the optical axis of a bar-like light conductive member disposed close to an end surface of the transparent substrate, the grooves are each formed substantially trapezoidal in section with their bottom surface defining a shorter side of trapezoid.

Abstract: A magnetic head that is excellently adapted to a magnetic core reduced in thickness. When a magnetic core which is reduced in thickness for adaptation to a high recording density is inserted in an opening of a size conventionally formed in a magnetic head of a standard recording density type, a spacer made of a material equivalent or identical to that of a slider is inserted between the magnetic core and the inner wall of the opening. The magnetic core is positioned by means of projections formed on the inner wall of the opening and the spacer. Then, glass as a sealing material is poured into gaps formed in the opening by the magnetic core, the inner wall of the opening and the spacer. The inserted spacer reduces a space volume for the glass to be poured. Further, since the spacer is made of the material equivalent or identical to that of the slider, a partial abrasion at a sliding surface of the slider sliding on a recording medium can be eliminated.

Abstract: A magnetic head which can improve workability in coil formation, prevent wiring errors and is compatibly applicable to recording media having respective recording densities different from each other. Twelve cut-outs (11) are formed on four walls (10) at respective edges of a back yoke (5) and lead wires (15a, 15b) of a read/write coil (15) and lead wires (16a, 16b) of a read/write coil (16) are let separately through the respective cut-outs (11), whereby the lead wires (15a, 15b and 16a, 16b) are not mistaken for each other in wiring. Since first and second magnetic cores (2 and 3) and the read/write coils (15 and 16) corresponding thereto are provided, the magnetic head is capable of reading and writing on two recording media having respective recording densities different from each other, thereby providing compatibility for magnetic recording.

Abstract: An optical servo magnetic head in which the rigidity in a slider is maintained, and a servo error due to dust particles is suppressed. In a separate type magnetic head (1) generally composed of a slider (2) and a back yoke (3), the slider (2) is provided with magnetic cores (11 and 12) for standard recording density and high recording density, respectively, in order to cover, with a single unit of magnetic head, a plurality of recording media having respective recording densities different from each other. A laser beam is used to guide the magnetic head to a prescribed track position, and passage-holes (5 and 6) for permitting the laser beam to pass through are formed through the slider (2) and the back yoke (3), respectively, by molding or machining.

Abstract: A cut out 23 is formed at the corner portion 22 which is formed between the second long side 822 and each of the first and second short sides 811 and 812 of the back yoke 5, in which the terminal stands 20d of the bobbins 20 of the read/write coil 6 and the erasing coil 7 are disposed respectively, a shield cover 32 is provided in such a manner as it is coupled with the first, second and third leg portions 10a, 10b and 10c including the wiring 6A of the read/write coil 6 and the wiring 7A of the erasing coil 7 and the front core 3 is bonded to the outer body 8 and the shield cover 32. Thereby, the bridging portion which has been necessary in the conventional example is almost eliminated, as a result, the strength of the front core 3 is increased to prevent it from being broken due to any shocking force.

Abstract: In a transparent and spread illuminating apparatus 1, a light reflection pattern 7 consisting of the concave and convex is formed on the front surface 6 of a transparent substrate 2 so that the emission light is allowed to be uniformly irradiated on the face of the transparent substrate 2 regardless of a distance from a light source lamp 4, and the light is facially irradiated on a reflection type liquid crystal display element L. In addition, a transparent member 11 for changing the progressing direction of the light reflected from the transparent substrate 2 is disposed between the reflection type liquid crystal display element L and the transparent substrate 2 so as to be in close contact with both surfaces thereof. As a result, the degradation of the contrast which makes the observation of an image difficult and the generation of the moire pattern can be prevented.

Abstract: A spread illuminating apparatus 1 according to the present invention includes a transparent substrate, a linear light source made up of a light reflector 16 as an optical path conversion portion and/or a light conductor 13 made of a linear transparent material and having optical path conversion portion at least, on either side and disposed closely along at least one side end surface 3 of a transparent substrate 2, and a dot-shaped light source 12 disposed on one end portion 14 of the light conductor 13. The light emitted from the dot-shaped light source 12 enters the light conductor 13/or reflected on the light reflector, and the light emitted from a surface 18 opposing to the transparent substrate 2 enters the transparent substrate 2, to thereby become a linear light source as a whole. Accordingly, since a fluorescent lamp which has been employed as a conventional light source is not used, impact resistance is improved, and illumination is enabled at a low voltage.

Abstract: A floating magnetic head comprising a substantially rectangular slider made of a non-magnetic substance and having leading and trailing ends. The slider is provided with a groove which gradually increases in depth along one side of the slider extending toward the trailing end and has an opening at the trailing end. The slider has rails mounted on a surface of the slider that is opposite to a magnetic recording medium to produce a floating force. A magnetic head core is bonded to one side of the slider. The core has a read/write gap, first and second legs, an inclined face opposite to the bonding surface, and a track width on the surface opposite to the magnetic recording medium. The second leg is located at the trailing end of the slider without protruding from the trailing end.