Site: Volga Research and Development Institute
Prospect 50 Let Oktyabrya 101
410052, Saratov, Russia
Telephone: (845-2) 13-21-35
Fax: (845-2) 13-21-33

Date Visited: October 27-28, 1993

Report Author: J. Talbot

ATTENDEES

WTEC:

D. Slobodin
J. Talbot

HOSTS:

Dr. Boris I. Gorfinkel ; Director

BACKGROUND

The Volga R&D Institute was founded in 1953 as the research center for the Reflector production company. In the 1950s and 1960s, the institute was the principal enterprise in the USSR that was developing receiver tubes. Now, the main research and development projects include vacuum cathodoluminescence displays, liquid crystal displays, and semiconductor lasers. The institute is a state enterprise, employing 1,000 people, of whom about 25 are Ph.D.s. Vacuum fluorescent displays have been designed at Volga for a variety of uses where the maximum number of lines and columns are 480 x 690, respectively. The first VFD was produced in 1971. The studies for VFD also include development of low- voltage phosphors and flat matrix VFDs with planar control electrodes. Also, cold cathodes for field emission displays are being developed. Panelists observed an operative 4"-square FED.

The development and production of LCD began in 1973, first for watches and then for PCs, produced in a factory in Minsk. LCDs with STN are being developed for use in computers and with small relaxation times for television. TFTs with a MIM design using smectic C (ferroelectric materials) and smectic A are under development. The aim is to produce active-matrix LCDs with a control element based on a-Si on a glass substrate. Also, work on electrochromic displays is underway.

The institute designs semiconductor lasers, receiver-transmitter modules, and local optical fiber links. The institute also designs silicon ICs for display driving and use in receiver- transmitter modules. A booklet listing the specifications of LCDs, VFDs, and lasers designed by Volga is available.

RESEARCH AND DEVELOPMENT ACTIVITIES

The institute also has thin- and thick-film process technologies, vacuum evaporation, substrate cleaning processes, photolithography, and design capabilities for large-scale precision masks.

The goals of the research and development at Volga are to develop large-format (up to 100 m2) information panel displays featured with full-color, low voltage, and high brightness for use in advertisements and TV broadcasts.

Nearly all the raw materials required for LCD and VFD are produced in Russia. Sheet glass is redrawn at Reflector to make thinner by vertical drawing glass of 0.1-0.2 mm thickness to 0.04 mm for LCD use. For STN displays, very flat glass is required; thus, the redrawn glass is also polished. Volga develops devices and produces them on pilot lines, and Reflector does mass production. For example, Volga produces 100,000 LCDs or VFDs, whereas Reflector produces millions per year. There is a close association between the Volga Institute and other academic institutions. Also, statistical quality control was developed at Volga for electronic production, which is applied to production for displays. An STN of 30 cm-diagonal size and full-color has been developed.

A tour of the Volga laboratories showed indium-tin-oxide evaporation equipment, a roll coater for applying the alignment organic for LCDs, a lab for developing specialized phosphors, a facility for TFT twin-diode structure development, and reactive plasma etching equipment. The Volga labs occupy the top two floors of the Reflector facility. A bag-filtration system in the labs results in a high-class local cleanliness environment.

For phosphor development, the emphasis is on low voltage using ZnO for green, Zn/Cd for red, and ZnS for blue. Low-voltage phosphors would range from 4 V to 20 V (for color). For 200-300 V applications, ZnS is used for green and blue, and Y-oxysulfide is used for red (TV analog materials). The screen processing methods used are silk-screening and electrophoretic deposition. The ZnO for green has a luminous efficiency of 10-12 lm/W. Using silk-screening techniques, lines of 100-150 şm thick of phosphor has been deposited. Volga's scientists are studying ZnS and ZnO for FEDs. Some work has been done on thick film (10 şm) Zn sulfides and oxides, but not thin-film materials. The phosphors developed at Volga are then mass-produced at the government stock company of Stavropol, 355036 Prospekt Kulakovda 8, Stavropol (Dr. Vladimir Vituk, Director).

Volga's scientists showed the TFT LCD design, which used a diode back-to-back structure and Ti and Ta metal contacts. Volga's scientists showed a 14-cm diagonal screen with 240 lines and 756 columns, and were developing an 856 x 856 display, and an 8-inch diagonal using smectic A, with a design similar to that of Crossland, et al., at the University of Manchester. This latter display has a half-spheric viewing angle, unlimited multiplexing, and 20,000 hrs of memory.

The scientists demonstrated a dry etching process for FEDs with Cr, SiO2, and Al for a 128 x 128 (1,000 pixel) display. Automated glass cleaning, with H2O2 and NH4OH, was used. For FED development, researchers are pursuing the Spindt approach with Mo tips. However, they also are investigating designs with a graphite emitter edge, with a 1 şm anode-cathode separation and with a razor edge. The scientists showed a working 4"- square FED with a green rastor.

OTHER RESEARCHERS

REFERENCES

Alieve, D.F., V.L. Aristov, V.V. Mitrokhin, and V.P. Sevostyarov. 1991. "Operating Characterization of a Smectic A LCD." Display. April:86-90.

Chubin, N.N., B. Ch. Djubua, S.I. Gorfinkel, and E.V. Rusina. 1991. "Field-Emission Array Cathodes for a Flat-Panel Display." Technical Digest of IVMC91, Japan Conference: IV-4.

Paper from Eurodisplay. "Degradation and Lifetime of Low- Voltage Phosphors."


Published: December 1994; WTEC Hyper-Librarian