PD2435 Datasheet, PDF (11/11 Pages) OSRAM GmbH – 4-Character 5 x 7 Dot Matrix Alphanumeric Programmable Display™ with Built-in CMOS Control Functions

Post Solder Cleaning Procedures
The least offensive cleaning solution is hot D.l. water (60°C) for
less than 15 minutes. Addition of mild saponifiers is acceptable.
Do not use commercial dishwasher detergents.
For faster cleaning, solvents may be used. Carefully choose the
solvents as some may chemically attack the package. Maxi-
mum exposure should not exceed two minutes at elevated
temperatures. Acceptable solvents are: TF (trichlorotrifluoroet-
hane), TA, 111 Trichloroethane, and unheated acetone. ⁽¹⁾
Note:
1) _{Acceptable commercial solvents are: Basic TF Arklone P.}
Genesolv D, Genesolv DA, BlacoTron TF, Blaco-Tron TA and,
Freon TA.
Do not use solvents containing alcohol, methanol, methylene
chloride, ethanol, TP35, TCM, TMC, TMS+, TE, and TES. Since
many commercial mixtures exist, you should contact your pre-
ferred solvent vendor for chemical composition information.
Some major solvent manufacturers are: Allied Chemical Corpo-
ration, Specialty Chemical Division, Morristown, NJ; Baron-
Blakeslee, Chicago, IL; Dow Chemical, Midland, Ml; E.l. DuPont
de Nemours & Co., Wilmington, DE.
For further information refer to Appnotes 18 and 19.
An alternative to soldering and cleaning the display modules is
to use sockets. Naturally, 20 pin DIP sockets 0.600" wide with
0.100" centers work well for single displays. Multiple display
assemblies are best handled by longer SIP sockets or DIP
sockets when available for uniform package alignment. Socket
manufacturers include: Aries Electronics, Inc., Frenchtown,
NJ; Garry Manufacturing, New Brunswick, NJ; Robinson-
Nugent, New Albany, IN; and Samtec Electronic Hardware,
New Albany, IN.
For further information refer to Appnote 22.
Optical Considerations
The character heights of these displays allows readability up to
eight feet. Proper filter selection allows the user to build a dis-
play that can be used over this distance.
Filters allow the user to enhance the contrast ratio between a
lit LED and the character background. This will maximize dis-
crimination of different characters as perceived by the display
user. The only limitation is cost. So first consider the ambient
lighting environment to maximize the cost benefit ratio for
using filters.
Incandescent (with almost no green) or fluorescent (with
almost no red) lights do not have the flat spectral response of
sunlight. Plastic band-pass filters are inexpensive and effective
in optimizing contrast ratios. The PD2435/3535/4435 is high
efficiency red display and should be matched with a long
wavelength pass filter in the 570 nm to 590 nm range. The
PD2436/3536/4436 is a standard red display and should be
matched with a long wavelength pass filter in the 600 nm to
620 nm range. The PD2437/3537/4437 should be matched
with a yellow-green band-pass filter that peaks at 565 nm. For
displays of multiple colors, neutral density grey filters offer the
best compromise.
Additional contrast enhancement can be gained through shad-
ing the displays. Plastic band-pass filters with built-in louvers
offer the “next step up” in contrast improvement. Plastic filters
can be further improved with anti-reflective coatings to reduce
glare. The trade-off is “fuzzy” characters. Mounting the filters
close to the display reduces this effect. Care should be taken
not to overheat the plastic filters by allowing for proper air flow.
Optimal filter enhancements for any condition can be gained
through the use of circular polarized, anti-reflective, band-pass
filters. The circular polarizing further enhances contrast by
reducing the light that travels through the filter and reflects back
off the display to less than 1%. Proper intensity selection of the
displays will allow 10,000 foot candle sunlight viewability.
Several filter manufacturers supply quality filter materials.
Some of them are: Panelgraphic Corporation, W. Caldwell, NJ;
SGL Homalite, Wilmington, DE; 3M Company, Visual Products
Division, St. Paul, MN; Polaroid Corporation, Polarizer Division,
Cambridge, MA; Marks Polarized Corporation, Deer Park, NY;
Hoya Optics, Inc., Fremont, CA.
One last note on mounting filters: recessing display and bezel
assemblies is an inexpensive way to provide a shading effect in
overhead lighting situations. Several Bezel manufacturers are:
R.M.F. Products, Batavia, IL; Nobex Components, Griffith Plas-
tic Corp., Burlingame, CA; Photo Chemical Products of Califor-
nia, Santa Monica, CA; I.E.E.Atlas, Van Nuys, CA.
See Appnote 23.
 2001 OSRAM Opto Semiconductors Inc.• San Jose, CA
www.infineon.com/opto • 408-456-4000
OSRAM Opto Semiconductors GmbH & Co. OHG • Regensburg, Germany
www.osram-os.com • [phone]
11
PD2535/6/7, PD3535/6/7, PD4435/6/7
July 5, 2001-14