5–6

DLR/DLO/DLG2416

Design Considerations

For details on design and applications of the DLX2416 using

standard bus configurations in multiple display systems, or

parallel I/O devices, such as the 8255 with an 8080 or memory

mapped addressing on processors such as the 8080, Z80,

6502, or 6800, refer to Appnote 15 in the current Siemens

Optoelectronics Data Book.

Electrical and Mechanical Considerations

Voltage Transient Suppression

We recommend that the same power supply be used for the

display and the components that interface with the display to

cause transients in the power supply line while they change

display states. The common practice is to place .01 mF capac-

itors close to the displays across VCC and GND, one for each

display, and one 10 mF capacitor for every second display.

ESD Protection

The silicon gate CMOS IC of the DLX2416 is quite resistant to

ESD damage and capable of withstanding discharges greater

than 2 KV. However, take all the standard precautions, normal

for CMOS components. These include properly grounding per-

sonnel, tools, tables, and transport carriers that come in con-

tact with unshielded parts. If these conditions are not, or

cannot be met, keep the leads of the device shorted together

or the parts in anti-static packaging.

Soldering Considerations

The DLX2416 can be hand soldered with SN63 solder using a

grounded iron set to 260

°C.

Wave soldering is also possible following these conditions:

Preheat that does not exceed 93

°C on the solder side of the PC

board or a package surface temperature of 85

°C. Water solu-

ble organic acid flux (except carboxylic acid) or resin-based

RMA flux without alcohol can be used.

Wave temperature of 245

°C ±5°C with a dwell between 1.5

sec. to 3.0 sec. Exposure to the wave should not exceed tem-

peratures above 260

°C for five seconds at 0.063" below the

seating plane. The packages should not be immersed in the

wave.

Post Solder Cleaning Procedures

The least offensive cleaning solution is hot D.I. water (60

°C) for

less than 15 minutes. Addition of mild saponifiers is accept-

able. Do not use commercial dishwasher detergents.

For faster cleaning, solvents may be used. Carefully select any

solvent as some may chemically attack the nylon package.

Maximum exposure should not exceed two minutes at elevated

temperatures. Acceptable solvents are TF (trichorotribluore-

thane), TA, 111 Trichloroethane, and unheated acetone.

Note:

Acceptable commercial solvents are: Basic TF, Arklone,

P. Genesolv, D. Genesolv DA, Blaco-Tron TF, Blaco-Tron TA,

and Freon TA.

Unacceptable solvents contain alcohol, methanol, methylene

chloride, ethanol, TP35, TCM, TMC, TMS+, TE, or TES. Since

many commercial mixtures exist, contact a solvent vendor for

chemical composition information. Some major solvent manu-

facturers are: Allied Chemical Corportation, Specialty Chemical

Division, Morristown, NJ; Baron-Blakeslee, Chicago, IL; Dow

Chemical, Midland, MI; E.I. DuPont de Nemours & Co., Wilm-

ington, DE.

For further information refer to Siemens Appnotes 18 and 19.

An alternative to soldering and cleaning the display modules

is to use sockets. Standard pin DIP sockets .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 are Aries Electronics, Inc., French-

town, NJ; Garry Manufacturing, New Brunswich, NJ; Robin-

son-Nugent, New Albany, IN; and Samtec Electronic

Hardware, New Albany, IN.

For further information refer to Siemens Appnote 22.

Optical Considerations

The 0.200" high characters of the DLX2416 gives readability

up to eight feet. Proper filter selection enhances readability

over this distance.

Filters enhance the contrast ratio between a lit LED and the

character background intensifying the discrimination of differ-

ent characters. The only limitation is cost. Take into consider-

ation the ambient lighting environment for the best cost/

benefit ratio for 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 an inexpensive and

effective way to strengthen contrast ratios.

The DLR2416 is a standard red display and should be

matched with long wavelength pass filter in the 600 nm to

620 nm range. The DLO2416 is a high efficiency red display

and should be matched with a long wavelength pass filter in

the 470 nm to 590 range. The DLG2416 should be matched

with a yellow-green band-pass filter that peaks at 565 nm. For

displays of multiple colors, neutral density gray filters offer

the best compromise.

Additional contrast enhancement is gained by shading the

displays. Plastic band-pass filters with built-in louvers offer

the next step up in contrast improvement. Plastic filters can

be improved further with anti-reflective coatings to reduce

glare. The trade-off is fuzzy characters. Mounting the filters

close to the display reduces this effect. Take care not to over-

heat the plastic filter by allowing for proper air flow.

Optimal filter enhancements are gained by using circular

polarized, anti-reflective, band-pass filters. Circular polariz-

ing further enhances contrast by reducing the light that trav-

els through the filter and relfects back off the display to less

than 1%.

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, Polar-

izer Division, Cambridge, MA; Marks Polarized Corporation,

Deer Park, NY, Hoya Optics, Inc., Fremont, CA.

One last note on mounting filters: recessing displays and

bezel assemblies is an inexpensive way to provide a shading

effect in overhead lighting situations. Several Bezel manufac-

turers are: R.M.F. Products, Batavia, IL; Nobex Components,

Griffith Plastic Corp., Burlingame, CA; Photo Chemical Prod-

ucts of California, Santa Monica, CA; .E.E.-Atlas, Van Nuys,

CA.

Refer to Siemens Appnote 23 for further information.