Abstract: A rotatable rod includes a plurality of cylindrical center rods and a plurality of joints. Each joint connects between corresponding two of the plurality of center rods. Each of opposed ends of each center rod has at least one engaging projection, which projects from the end of the center rod in a direction parallel to an axial direction of the center rod. Each of opposed ends of each joint has at least one engaging recess, each of which is engaged with a corresponding one of the at least one engaging projection that is provided in an adjacent one of the ends of a corresponding one of the plurality of center rods.

Abstract: A rotatable rod includes a plurality of cylindrical center rods and a plurality of joints. Each joint connects between corresponding two of the plurality of center rods. Each of opposed ends of each center rod has at least one engaging projection, which projects from the end of the center rod in a direction parallel to an axial direction of the center rod. Each of opposed ends of each joint has at least one engaging recess, each of which is engaged with a corresponding one of the at least one engaging projection that is provided in an adjacent one of the ends of a corresponding one of the plurality of center rods.

Abstract: An optical apparatus uses an array of light-emitting elements (LEDs or ELs) and a focusing optical system. Light emitted from the light-emitting elements of the array is directed to the focusing optical system within narrowed solid angles, thereby raising overall light utilization efficiency, with the help of recesses, each shaped as an inverted conical frustum, centered at respective light-emitting elements, to collect light from the light-emitting elements and deliver it to the focusing system within narrower solid angles, as both direct light and indirect light reflected from the slanting side walls of the recesses. The side walls of the recesses can have a reflecting film to further enhance overall light utilization efficiency. Lenses can be formed integrally with the array, to further help focus the light delivered to the focusing optical system.

Abstract: The present invention relates to a LED array head which includes a base plate, and an array of protruding LED light-emitting portions formed on the base plate. Further, a mirror array including reflection mirror structures is formed on an upper circumferential surface of corresponding LED light-emitting portions, thereby narrowing a radiation angle of light emitted by the corresponding light-emitting portions. In addition, the reflection mirror structures have a circular cone frustum shape with a diameter at an upper emission side larger than a diameter at a lower emission side. The present invention also relates to a minute reflection optical elements array of an optical writing apparatus having an array of light-emitting elements formed on a base plate of an LED array head. The optical elements array includes opening portions having a tapering cross-section shape which becomes narrower in a direction toward the base plate at sides opposing corresponding light-emitting elements.

Abstract: An optical apparatus uses an array of light-emitting elements (LEDs or ELs) and a focusing optical system. Light emitted from the light-emitting elements of the array is directed to the focusing optical system within narrowed solid angles, thereby raising overall light utilization efficiency, with the help of recesses, each shaped as an inverted conical frustum, centered at respective light-emitting elements, to collect light from the light-emitting elements and deliver it to the focusing system within narrower solid angles, as both direct light and indirect light reflected from the slanting side walls of the recesses. The side walls of the recesses can have a reflecting film to further enhance overall light utilization efficiency. Lenses can be formed integrally with the array, to further help focus the light delivered to the focusing optical system.

Abstract: An optical device of the present invention includes an input aperture array formed with a plurality of input apertures at a preselected period of arrangement. An output aperture array is formed with a plurality of output apertures respectively facing the input apertures at a preselected period of arrangement. An aperture array intervenes between the input aperture array and the output aperture array and is formed with apertures respectively facing the input apertures and output apertures at a preselected period of arrangement. The aperture array satisfies the following two conditions:t2>T.multidot.(r+R)/(P+r-.rho.)t1<t2.multidot.(P-.rho.-r)/(P+.rho.-r)where T denotes a distance between the input aperture array and the output aperture array, r denotes the half-width of the input apertures, .rho.

Abstract: An optical EXCLUSIVE-OR element in which the number of basic elements is reduced which results in increased integration of the element. The optical EXCLUSIVE-OR element comprises a substrate, a first optical functional element and a second optical functional element having the same structure as that of the first optical functional element. Each of the first and second optical functional elements has a light receiving portion and a light emitting portion. The light emitting portion is formed on the light receiving portion. The light emitting portion comprises semiconductor materials having an energy gap wider than the dominant peak energy of the input light, and the light receiving portion comprises semiconductor materials having an energy gap equal to or narrower than the dominant peak energy of the input light. A first electrode is formed over the first and second optical functional elements, and has windows which allow the input light and output light to pass through.

Abstract: An optically functional device has a semiconductor substrate, a light receiving portion disposed on the semiconductor substrate for receiving input light, a light emitting portion disposed on the light receiving portion for emitting output light, a window disposed above the light emitting portion, through which input light and output light pass and a resistance layer made of a semiconductor for functioning as load resistance. The resistance layer is disposed at least in either place between the semiconductor substrate and the light receiving portion, or between the light receiving portion and the light emitting portion, or on the light emitting portion. The light emitting portion has a light emitting layer made of semiconductor material having an energy of forbidden band width of more than the energy of a main peak of input light.