Abstract: A thickness of each hologram lens for forming a hologram color filter is set so as to be smaller as the wavelength of light to be diffracted by each hologram lens is shorter. A thin plate glass layer is bonded to a surface of the hologram color filter such that it is in a firm contact therewith by adhesive agent and a sum of the thickness of the thin plate glass layer and thickness of the adhesive agent is smaller than the shortest focal length of the focal lengths in glass of a plurality of the hologram lenses. As a result, light diffracted and divided by the hologram color filter is focused on a picture element electrode of a corresponding color properly thereby eliminating deterioration of color reproduction due to mixing of colors. Further, upon production of the hologram color filter from hologram recording material, an influence of a fringe rotation is compensated.

Abstract: A thickness of each hologram lens for forming a hologram color filter is set so as to be smaller as the wavelength of light to be diffracted by each hologram lens is shorter. A thin plate glass layer is bonded to a surface of the hologram color filter such that it is in a firm contact therewith by adhesive agent and a sum of the thickness of the thin plate glass layer and thickness of the adhesive agent is smaller than the shortest focal length of the focal lengths in glass of a plurality of the hologram lenses. As a result, light diffracted and divided by the hologram color filter is focused on a picture element electrode of a corresponding color properly thereby eliminating deterioration of color reproduction due to mixing of colors. Further, upon production of the hologram color filter from hologram recording material, an influence of a fringe rotation is compensated.

Abstract: A color separating/light guiding optics comprises two independent dichroic mirrors, reflection mirrors and correcting lenses. A horizontal plane region occupied by these optical components is entirely involved in a horizontal plane region occupied by a light modulating/color compositing/image projecting optics. A red beam is guided along a detoured optical path extending across a dead space below a projection lens. Although the optical path length of the red beam becomes longer than those of the blue beam and the green beam, the detoured optical path provides a sufficient space for installing the correcting lenses. The substantial optical path lengths of three primary color beams can be equalized with each other by the provision of these correcting lenses.

Abstract: A color filter includes a plurality of color pixels, and a first hologram diffracting an incident light beam into a first diffraction-resultant light beam. The color filter also includes a second hologram diffracting the first diffraction-resultant light beam into a second diffraction-resultant light beam having a plurality of light beams with different wavelengths respectively. The second hologram directs the different wavelength light beams toward the color pixels respectively.

Abstract: Novel magnetic alloys for magnetic heads are provided and are broadly of the formula, Fe-O-N. In a more specific embodiment, the alloys are of the compositional formula, Fe.sub.v N.sub.w O.sub.x M.sub.y, wherein M represents a member selected from the group consisting of Ta, Nb, Si and mixtures thereof, and v, w, x and y are, respectively, such values by atomic percent that 1.ltoreq.w.ltoreq.20, 1.ltoreq.x.ltoreq.20 and 0.5.ltoreq.y.ltoreq.6 provided that v+w+x+y=100. These alloys may further comprise at least one element of the platinum group or of group VIa of the periodic table in an amount of from 0.3 to 3 atomic percent in total so that their resistance to corrosion is improved.

Abstract: A magnetic head using an MR element and a permanent magnet for applying a bias magnetic field to the MR element, and a lead frame of the head. A sheet of metal is punched or otherwise shaped in a predetermined pattern to produce the lead frame. The lead frame includes sections mounting the MR element and permanent magnet, lead connecting sections electrically connected to connecting sections of the MR element, and tape-contact sections which are flush with a tape-contact surface of the MR element. The lead frame mounted with the MR element and permanent magnet and provided with the lead connecting sections is placed in a metal mold having a predetermined configuration and buried and fixed in place in synthetic resin.

Abstract: A magnetic recording and/or reproducing element comprises a main element body, and windings wound around the main element body. The main element body has a pair of extremely thin layers made from a ferromagnetic material, and the extremely thin layers oppose each other at respective edges thereof so as to constitute a gap. Each of the thin layers are sandwiched between a pair of support members which are made from a non-magnetic and abrasion proof material. A contact surface is formed on a vertex part of the main element body, for making contact with a magnetic recording medium so as to record and/or reproduce a signal on and/or from the magnetic recording medium. The main element body has one or a plurality of side surfaces which form a predetermined angle with respect to the contact surface and define the peripheral edge of the contact surface so that the contact surface has a predetermined shape with an extremely small area and has the gap at an approximate center of the predetermined shape.