Abstract: In a vehicle seat, a central support member typically consisting of wire mesh or grid and supports most of the load of the vehicle occupant via spring members, and undergoes a relatively large displacement when the occupant is seated in the seat. Thus, by detecting the displacements of various parts of the central support member, preferably peripheral parts thereof, the magnitude of the total load and distribution of the load can be evaluated both reliably and accurately. Additionally, displacement sensors for measuring such large displacements are relatively inexpensive and easy to handle. Also, such sensors would not interfere with the existing seat designs, and would not be adversely affected by the equipment of the seat such as seat heaters.

Abstract: In a vehicle seat, a central support member typically consisting of wire mesh or grid and supports most of the load of the vehicle occupant via spring members, and undergoes a relatively large displacement when the occupant is seated in the seat. Thus, by detecting the displacements of various parts of the central support member, preferably peripheral parts thereof, the magnitude of the total load and distribution of the load can be evaluated both reliably and accurately. Additionally, displacement sensors for measuring such large displacements are relatively inexpensive and easy to handle. Also, such sensors would not interfere with the existing seat designs, and would not be adversely affected by the equipment of the seat such as seat heaters.

Abstract: To prevent unauthorized duplication of an information storage cards such as magnetic cards, IC cards, and optical cards, the card carries an identification region which may be identified by a simple optical sensor. The identification region may consist of holograph, diffraction grating, a multiplicity of parallel grooves and other processed surfaces having certain reflective or transmissive directivities. In particular, the identification region comprises a plurality of segments having two or more different reflective or transmissive directivities, and these segments are uniformly distributed in the identification region so that all of the segments may be accessed simultaneously by the optical sensor which comprises a light emitter and a light receiver including a plurality of parts each capable of individually detecting light reflected by or transmitted through the identification region.

Abstract: A highly simple and compact optical head for optically determining authenticity of an article by impinging a light beam upon an identification region provided on the article and having a selected reflective directivity, and receiving light reflected by the identification region. The identification region may consist of a holograph, a diffraction grating or a multiplicity of parallel grooves. The optical head comprises a light emitting element fixedly secured to a casing and a light receiving element placed coaxially in a light path of a light beam emitted from the light emitting element and having an opening for allowing the light beam to pass through the light receiving surface facing away from the light emitting element and being divided into a plurality of sectors defined around an axial center line of the light emitting element with each of the sectors being capable of individually detecting a magnitude of light impinging thereon.

Abstract: An optical head for reading and/or writing information from and in an optical recording medium having an improved sensor structure for focusing and tracking error detections. A light beam is separated into a 0th-order diffraction light beam and .+-.1st-order diffraction light beams, and these light beams are impinged upon a recording track of the optical recording medium. The light beams reflected from the optical recording medium is separated into two different directions, and the tracking and focusing error detections are carried out with multi-segment optical sensors which are connected in a complementary manner. As a result, the influence of the tracking error on the focusing error detection is eliminated, and the linearity of the focusing error detection is improved.

Abstract: An optical head structure, comprising: a light source; an optical system for projecting a first light beam from the light source upon an optical data recording medium and guiding a second light beam produced from the optical data recording medium as a result of projecting the first light beam, as a converging light beam; a light detecting element having at a photoelectric surface area divided into at least three surface parts, consisting of a central band part extending centrally and diametrally across the surface area and a pair of adjoining outer parts which are arranged on either side of the central band part, to receive the second light beam at a position in a path of the second light beam slightly displaced from a focal point of the second light beam; and a subtracter for producing a difference between an output from the central band part and a sum of outputs of the adjoining parts; the central band part being progressively narrower as it extends away from a central part of the photoelectric surface area