Site: Nippon Sheet Glass Co., Ltd. (NSG)
Tsukuba Research Center
5.4, Tokodai, Tsukuba City
Ibaraki Pref. 300-26, Japan

Date Visited: November 15, 1995

Report Author: S. Esener



S. Esener
D. Keck
G. Saxonhouse


Dr. Yoshinobu Mitsuhashi
General Manager, Technical Planning and Administration Department
Kenjiro Hamanaka
Senior Researcher, R&D group


Nippon Sheet Glass (see the preceding site report on NSG's Sagamihara facility for overall NSG background description) has three research centers: its central research facility in Itami, its technical center at Sagamihara, and its optoelectronics devices and thin-film technology research center in Tsukuba. Of NSG's 300 or so researchers, about 20% are doing optoelectronics work. The Tsukuba facility has 40 scientists, down from 60 in 1991.

NSG's Tsukuba Research Center aims to develop solar energy control and intelligent glass as well as to undertake research in micro-optics and optoelectronics. The center's focus is on light and heat control through glass, providing substrates for recording media, and displaying information on glass by LCDs. The center is focusing on LCDs and has nearly abandoned electroluminescence for displays. The center's scientists depend heavily on their vacuum coating technologies. They are applying the SELFOC lens concept to micro-optics leading to microlens arrays, optical waveguides, and silicon bench technologies such as OBIS (Optical Bus Interconnection System).

NSG Techno Research (NSG-TR), which is in the same building, was spun-off from the Tsukuba Research Center to provide services such as evaluation and measurements for other groups inside and outside NSG. NSG-TR started in April 1994, and it has significant interaction with Tsukuba Research Center personnel.


Smart Glass

NSG sells automobile glass to all manufacturers, but the profits come from high-priced cars, which was a shrinking market. Low-cost requirements hit the company, which found that vacuum deposition equipment is too costly for mass production. The company's main technical success in 1994 was a water repellent coating for the windows, using a sol-gel technology with a dopant. The company's representatives showed the JTEC panel very large (entire auto window) LCD windows. They also showed very large area grating layers put in the glass to alter angle of view. This can be used in building glasses for privacy.

Glass Disks For Data Storage

NSG supplies glass disks to Hitachi-Maxell for optical data storage. NSG also supplies magnetic hard disks using glass substrates. These disks are ion exchanged for strength and must be polished for flatness. The company's scientists are experimenting with sol-gel coatings that can be patterned for grooving the disks, presently viewed as very expensive.

Vacuum Coating

NSG has developed an antistatic and antireflection coating for CRTs. It expects to be able to apply to the front panel before sealing. The JTEC team witnessed the dramatic difference in the performance of coated and noncoated displays.


The panel was shown 2-D lens arrays fabricated by the Iga process to be used with projection LCDs. The center is making 4 x 5 units with 300,000 lenslets in each. The lens array diagonal is 3 in. The lenslet array significantly improves the display luminance.

Waveguide Couplers

(See discussion in previous NSG report, page 279.)

Imaging Fibers

NSG has also a joint venture with Olympus to do imaging fibers. It has close to $10 million in sales/year from one furnace. A SELFOC lens is attached to the fiber bundle.

Evaluation Facilities

As evaluation and characterization facilities, the Tsukuba center provides electron microscopes (TEM and SEM), an X-ray microanalyzer, SIMS, FT-IR, and an induction coupled spectrophotometer.

MITI-Funded Projects

NLO project (Koyama)

NSG has had a project doing layered semiconductor doping. Particles of CdTe are layered with SiO 2 in a repeated fashion using laser-assisted PECVD. NSG scientists can control the particle size, and it showed a distribution from 2 to 5 nm with an average of 3 nm. JTEC's hosts quoted values of x=3 - 2.7E-7 esu and alpha = 800 cm -1. Response times were about 1 psec. The equipment for the experiment came from MITI.

OBIS project (Hamanaka)

The OBIS project is aimed at packaging efficiently free-space optical interconnect concepts. It uses lines of SELFOC lenses (casted in a steel package) and partially transmitting prisms to deflect collimated beams out of the line to various 2-D receivers of transmitter arrays. Various components such as beam splitters are inserted into grooves that are fabricated by a diamond cutter. The SELFOC lenses are 4 mm in diameter. Thus far, they can transmit 130 x 130 pixels (16 microns diameter pixels) along each line.

Optical fiber sensors

About 10 years ago, MITI funded a program in optical fiber sensors. Currently no MITI program exists, and NSG has no program in optical fiber sensors


Regarding technology transfer, NSG's research cycle is about 5 years long. Fifty to seventy percent of people rotate to production and transfer forward and back to research.

Published: February 1996; WTEC Hyper-Librarian