Display vendor and glass
producer ally to make thin CRTs

A development and supply agreement between flat-panel display maker
Candescent Technologies (San Jose, CA) and glass manufacturer Schott (Yonkers,
NY) could assist in bringing a new display type–the thin CRT (TCRT)–to
commercial markets as early as mid 1998. In the agreement, Schott places
an undisclosed equity stake in Candescent, which has committed to a long-term
procurement arrangement of Schott's glass. The two companies will develop
glass-processing and finishing technologies to tailor an economical glass
material and supply channel for Candescent's TCRT.

The TCRT (see below ) consists of two pieces of glass–provided
by Schott–separated by a 1-mm gap. The faceplate is coated with conventional
CRT phosphors, while an array of microscopic cathodes is formed on the
baseplate using thin-film-processing technology.

Each cathode is individually addressed to generate a multitude of electron
beamlets that excite adjacent phosphor dots. Unlike conventional CRTs that
require heating to generate the electron beam, the display is made using
cold-cathode technology–a power-stingy process that generates electrons
at room temperature. Additional power efficiency is gained because TCRTs
don't require a shadow mask, which can consume up to 80% of the power.

Schott's glass–the base component of the display–is low-alkali borosilicate
glass, part number D263, which ranges in thickness from 0.03 to 1.9 mm.
Suited for several display types including TNs, STNs, TCRTs, FEDs, and
PALCs, the glass is noted for its superior surface quality and flatness
and because it requires no additional polishing. The D263 is manufactured
using a down-draw technology that enables glass widths of up to 700 mm.

Because glass is the primary cost component in flat-panel display manufacturing,
developing a manufacturing process that is compatible with a more cost-effective
glass supply has played a major role in Candescent's TCRT engineering effort.
“Schott brings a premier set of glass technologies and research capabilities
that significantly bolster our strategy of providing a high-quality display
in large volumes while retaining a low intrinsic cost,” according
to Harry Marshall, chairman, president, and CEO of Candescent.

The companies will jointly invest in a final-processing assembly facility
that will eliminate the duplicate costs typically associated with inspecting
finished glass at both supplier and OEM locations. Schott also plans to
establish a melting facility for thin glass at its subsidiary Schott Glass
Technologies (Duryea, PA). The alliance between the two companies will
assist in creating the needed infrastructure for flat-panel displays in
the United States.

For more information on Candescent's TCRT display, contact Cheryl Edwards
at 408-360-2636, send e-mail to , or circle 475.
To learn more about Schott's thin glass, contact Barbara Augenblick at
914-378-3863 or circle 476.

TCRT display performance

Candescent's thin-CRT (TCRT) 2.3-in.prototype offers a 140 x 120 resolution
and uses a flat-shaped 3.5-mm-thick tube to achieve a thickness of less
than 8 mm. The display features 80 lines/in.and offers a 5-ms response
time for full-motion video.

The latest prototype, which was displayed during SID '97, measures 4.4-in.
diagonal and provides a 320 x 240 resolution with 3-bit color. The display
features a 160° viewing angle, a brightness of 100 cd/m² ,
and a contrast ratio of greater than 300:1. Power consumption is 1.2 W.

The company estimates that a 14-in.notebook using its thin-CRT will
consume approximately 3.2 W typ, which is less than today's AMLCD notebooks.
Like their larger CRT relatives, future TCRTs will offer 8-bit color, high
resolutions, wide viewing angles, and operate over a –207 to +707C
temperature range.

Also, because of their redundant architecture the displays will be easier
to manufacture than some other flat-panel display types. The initial commercial
offering–a color 4.5-in-diagonal 1/4-VGA thin CRT–will be sampling by
the end of the year and available in production quantities by mid 1998.
Other sizes ranging from 2 to 4, 4.5 to 6, and 12 to 14-in.diagonal are
planned.