This paper reviews optical technology in Japan and introduces the present status of Fuji Electric's optical technology in the following three categories:
(1)Light-activated devices and peripheral terminals, and devices for office machines (autofocus modules, molded laser diodes, etc.)
(2)Optical measuring, control and transmission devices and systems (optical Fieldbuses, optical control devices, bar-code readers, etc.)
(3)Devices and equipment utilizing light energy (amorphous silicon solar cells, slab type YAG laser, etc.)

Activities for the practical use of Fieldbuses have become very active. Fuji Electric has submitted a proposal of an optical Fieldbus based on the FFI system for an international standard, and is developing optical Fieldbus systems as the next generation of FFI. The optical Fieldbus has many merits compared with the electrical one. This paper describes the merits of the optical Fieldbus and Fuji Electric's activities for development.

The networks for composing control systems strongly demand transmission using optical fiber which is immune to noise and capable of high-speed, long-distance transmission. Fuji Electric is ready to offer optical transmission for the basic LANs up to field networks of control systems.
This paper outlines Fuji Electric's optical networks for control systems and also introduces new developments, an ultrahigh-speed network utilizing optical transmission (FDDI under development) and a multimedia, multiplex transmission system (FTDM).

The optical system using optical fibers based on optical technology have been applied widely to practical use making the most of its numerous merits. As a part of expansion of optical control apparatus that can take the place of conventional electrical components, Fuji Electric developed optical components using polymer-clad fiber which has realized a transmission distance of 300 m to 1 km, more than ten times longer than its former type. This paper describes an outline of the system, optical limit switches for detection optical push-button switches for operation and transceivers.

More importance is being attached to the preventive maintenance of electrical installations. Fuji Electric has developed small optical thermoswitches, new optical control devices using optical fiber's explosionproofness, high insulation and immunity to electrical noise. Their merit is that they can monitor the temperature of small live parts such as current-carrying busbar joints of terminal boards, breakers, etc. The optical system was designed with a lightray trace simulator capable of light power evaluation. Detection status is latched also on the switch side visibly. The detectable range with the series is from 60 to 120℃.

The bar-code system is an indispensable tool to the fields of POS, FA and physical distribution as an information input terminal. This paper introduces a bar-code reader "PK3" with built-in sensor and decoder which is developed for the use in the fields of FA and physical distribution where high speed and space reduction are required. This bar-code reader is characterized by its wide reading range using the twin-lens light receving system, the raster scanning immune to label stains, small size and compatibility with 100V AC, and the teaching function.

Fuji Electric has developed a molded laser diode (LD) for the compact disk player. This LD molded in organic resins can be offered at a lower price than the conventional can type LD. There had been a problem of the chip position and the beam angle being deformed by a change in the ambient temperature. The thermal deformation had been analyzed with the finite element method and was reduced enough by optimizing the clear resin thickness. The pickup test verified that the thermal deformation due to the ambient temperature of the improved LD was as low as the can type LD.

A pulsed-mode 1kW Nd : YAG slab laser has been developed for material processing. The laser oscillator consists of two YAG slab crystals which are 5.6mm thick, 18.4mm wide, and 176mm long and have a Brewster's angle edge. The resonator configuration was determined by analysis of thermal lens effect on each YAG slab crystal to inject the beam into an optical fiber with a core diameter of 0.8mm. A stainless steel plate with a thickness of 25mm was cut at a speed of 70mm/min using this laser beam through an optical fiber delivery system.

The electroluminescence (EL) display is popular in the industrial equipment market because of its high reliability and a long life span. In pursuit of "bright, easy-to-use display," Fuji Electric has developed a high-brightness EL display with a built-in interface controller utilizing field memory ICs. The display is compatible with RGB and VGA interfaces of personal computer output. The high-brightness EL display has two ASICs. The one is the controller of driver ICs for the EL panel divided in two, realizing high brightness, and the other is for exclusive use as the interface controller.

Aiming at wider application and improved productivity of solar cells for power generarion, Fuji Electric has studied an amorphous silicon solar cell fabricated on a plastic film substrate. The cell with a new monolithic series-connected structure named "SCAF" was fabricated by a newly developed fabrication process based on "stepping-roll" film deposition system. This paper describes the new process, its advantage, and the preliminary results of small-and large-area SCAF solar cells obtained from the prototype line. It also introduces the application of the SCAF solar cells to building material integrated photovoltaic modules.