Abstract: A light demultiplexer in which a signal and a noise in each channel may be distinctly separated is provided. The light demultiplexer comprises a light-receiving element array for receiving light beams demultiplexed every wavelength from a wavelength multiplexed light beam and arranged in a straight line. The light-receiving element array includes a plurality of light-receiving elements for monitoring signals, and a plurality of light-receiving elements for monitoring noises. The light-receiving elements for monitoring signals and the light-receiving elements for monitoring noise are alternately arrayed in a straight line the direction thereof is the same as that of the arrangement of the demultiplexed light beams.

Abstract: An edge-emitting thyristor having an improved external luminous efficiency and a self-scanning light-emitting device array comprising the edge-emitting thyristor are disclosed. To improve the external luminous efficiency of an edge-emitting light-emitting thyristor, a structure where the current injected from an electrode concentrates on and near the edge of the light-emitting thyristor is adopted.

Abstract: In an optical write head, a rod lens array, a substrate support member for supporting a substrate, and a driver circuit board are fixedly held by a support member. The support member and the substrate support member are formed from metallic material, and a frame of the rod lens array is formed from a glass plate. Further, distance between a light-emitting section of a light-emitting device array and a light-incident end face of the rod lens array is adjusted, by means of rotating eccentric pins. Further, light-emitting device array chips are die-bonded on the substrate bonded at predetermined positions on the substrate support member while the position of the substrate support member is taken as a reference plane.

Abstract: A light-receiving element array is provided in which the degradation of characteristic thereof due to the crosstalk may be prevented. An n-InP layer, an i-InGaAs layer, and an n-InP layer are stacked on an n-InP substrate. Zn is diffused into the topmost n-InP layer to form a p-type diffused region, resulting in a pin-photodiode. A passivation layer is deposited on the structure to a thickness such that a nonreflective condition is satisfied. On the passivation film, a light-shielding film is provided so as to cover the area between light-receiving elements.

Abstract: An edge-emitting thyristor having an improved external luminous efficiency and a self-scanning light-emitting device array comprising the edge-emitting thyristor are disclosed. To improve the external luminous efficiency of an edge-emitting light-emitting thyristor, a structure where the current injected from an electrode concentrates on and near the edge of the light-emitting thyristor is adopted.

Abstract: A self-scanning light-emitting element array using an end face light-emitting thyristor having improved external emission efficiency is provided. To improve the external emission efficiency of the end face light-emitting thyristor, the present invention adopts such structure that the current injected from an anode is concentrated to near the end face of the light-emitting thyristor. A self-scanning light-emitting element array is implemented by using such end face light-emitting thyristor.

Abstract: A light-emitting thyristor matrix array in which the area of a chip may be decreased is provided. A plurality of three-terminal light-emitting thyristors are arrayed in one line in parallel with the long side of the chip, a plurality of bonding pads are arrayed in one line in parallel with the long side of the chip. Thereby, the area of the chip becomes smaller.

Abstract: A surface light-emitting element having improved external light emission efficiency and a self-scanning light-emitting device using this surface light-emitting element are provided. To improve external light-emission efficiency, the light-emitting center is shifted to an area where there is no light shielding layer thereon. When the surface light-emitting element is a surface light-emitting thyristor of the PNPN structure, it is necessary to have such a construction that part of the injected current is prevented from flowing toward the gate electrode to improve external light emission efficiency. The self-scanning light-emitting device of this invention is accomplished by using this type of surface light-emitting element.

Abstract: The cost of a light-emitting element matrix array is reduced by implementing a function equivalent to a light-emitting thyristor by elements different therefrom. A plurality of combinational element are arrayed in one line. The plurality of combinational elements are divided into groups n by n. The bases of transistors included in each group are separately connected to base-selecting lines and the anodes of light-emitting diodes included in each group are commonly connected to one anode terminal every group.

Abstract: A light-receiving element array is provided in which the degradation of characteristic thereof due to the crosstalk may be prevented. An n-InP layer, an i-InGaAs layer, and an n-InP layer are stacked on an n-InP substrate. Zn is diffused into the topmost n-InP layer to form a p-type diffused region, resulting in a pin-photodiode. A passivation layer is deposited on the structure to a thickness such that a nonreflective condition is satisfied. On the passivation film, a light-shielding film is provided so as to cover the area between light-receiving elements.

Abstract: A light-emitting thyristor matrix array in which the area of a chip may be decreased is provided. A plurality of three-terminal light-emitting thyristors are arrayed in one line in parallel with the long side of the chip, a plurality of bonding pads are arrayed in one line in parallel with the long side of the chip. Thereby, the area of the chip becomes smaller.

Abstract: The light-emitting thyristor matrix array may be provided in which wiring are crossed without being electrically connected to each other. An array of three-terminal light-emitting thyristors in which a substrate is used as a common cathode or anode is divided into blocks n by n (n is an integer≧2), gates of n light-emitting thyristors included in each block are separately connected to n gate-selecting lines, and anodes or cathodes of n light-emitting thyristors included in each block are commonly connected to one terminal, respectively.

Abstract: A method for setting the amount of light in an array of light-emitting thyristors, each thyristor having I-L characteristic in which a luminous efficiency is decreased in a lower current field, is provided. According to the method, the amount of light emitted from a light-emitting thyristor is set so that a predetermined exposure energy may be obtained without decreasing a luminous efficiency of a light-emitting thyristor. The density D of a current to be supplied to the light-emitting thyristor to obtain a predetermined exposure energy is selected so as to satisfy the range of 3×Dth<D<100 MA/m2, wherein Dth is a threshold current density for light emission which is defined as a current density corresponding to the value of a current at a point where a tangent drawn at the value of a current corresponding to a current density of 50 MA/m2 with respect to the curve of the I-L characteristic intersects a current axis.

Abstract: A self-scanning light-emitting device is provided in which the amounts of light of light-emitting elements may be corrected to make the distribution of amounts of light in a luminescent chip or among luminescent chips uniform. The correction for amounts of light of light-emitting elements may be carried out by regulating the time duration of on-state of a light-emitting element or the voltage of a write signal applied to a light-emitting element. According to the present invention, the distribution of amounts of light becomes uniform, so that the printing quality of a printer using such self-scanning light-emitting device is improved.

Abstract: An optical printer head is provided in which light exposure of one pixel may be increased. An optical printer head for exposing a photosensitive drum to form pixels thereon comprises a light-emitting element array including two or more lines of light-emitting points, and a rod-lens array for projecting light emitted from the light-emitting array onto the photosensitive drum to form a line of light spots. Each of the lines of light-emitting points has the same pitch in a main-scanning direction in parallel with an axis of rotation of the photosensitive drum, and the light-emitting points of respective lines of light-emitting points are arranged so as to be lined up in a sub-scanning direction perpendicular to the axis of rotation of the photosensitive drum.

Abstract: A method of designing an optimum mask pattern for forming a metal line by an etching process, the metal line also effectively serving as a light-shielding layer, is provided. In this method, assuming that a mask pattern for forming a first metal line on a transparent insulating film has a width of “L1” overlapped with a first control electrode in a direction perpendicular to an array direction of of transfer elements, “L1” is selected so as to satisfy the following relation L1>(S+dS)+a, wherein “S” is the distance of side etching of the first metal line, “dS” is the dispersion of the distance of the side etching, and “a” is the misalignment of the mask pattern.

Abstract: The cost of a light-emitting element matrix array is reduced by implementing a function equivalent to a light-emitting thyristor by elements different therefrom. A plurality of combinational element are arrayed in one line. The plurality of combinational elements are divided into groups n by n. The bases of transistors included in each group are separately connected to base-selecting lines and the anodes of light-emitting diodes included in each group are commonly connected to one anode terminal every group.

Abstract: A method for setting the amount of light in an array of light-emitting thyristors, each thyristor having I-L characteristic in which a luminous efficiency is decreased in a lower current field, is provided. According to the method, the amount of light emitted from a light-emitting thyristor is set so that a predetermined exposure energy may be obtained without decreasing a luminous efficiency of a light-emitting thyristor. The density D of a current to be supplied to the light-emitting thyristor to obtain a predetermined exposure energy is selected so as to satisfy the range of 3×Dth<D<100 MA/m2, wherein Dth is a threshold current density for light emission which is defined as a current density corresponding to the value of a current at a point where a tangent drawn at the value of a current corresponding to a current density of 50 MA/m2 with respect to the curve of the I-L characteristic intersects a current axis.

Abstract: In an optical write head, a rod lens array, a substrate support member for supporting a substrate, and a driver circuit board are fixedly held by a support member. The support member and the substrate support member are formed from metallic material, and a frame of the rod lens array is formed from a glass plate. Further, distance between a light-emitting section of a light-emitting device array and a light-incident end face of the rod lens array is adjusted, by means of rotating eccentric pins. Further, light-emitting device array chips are die-bonded on the substrate bonded at predetermined positions on the substrate support member while the position of the substrate support member is taken as a reference plane.

Abstract: A method for dicing a semiconductor wafer into chips is provided, in which the peeling-off of a hard protective film on the surface of a semiconductor substrate may be avoided. Two parallel grooves are formed at a dicing area around a chip by an etching process. Then, SiO2 film is deposited on the GaAs substrate as a protective film. At this time, a bending portion at the interface between the protective films on the inner surface of the groove and the surface of the substrate. When the part between two grooves is cut by a dicing blade, a stress to the protective film caused by the edge of the blade is concentrated to the bending portion, resulting in a crack along the bending portion.