HPDL-1414 Datasheet, PDF (11/12 Pages) Agilent(Hewlett-Packard) – Four Character Smart Alphanumeric Displays

Display Blank HPDL-2416
As shown in Figure 4, the display
will be blanked if the blanking
input (BL) is held low. Note that
the display will be blanked
regardless of the state of the chip
enables (CE₁, CE₂) or write (WR)
inputs. The ASCII data stored in
the display and the cursor
memory are not affected by the
blanking input. ASCII data and
cursor data can be stored even
while the blanking input (BL) is
low. Note that while the blanking
input (BL) is low, the clear (CLR)
function is inhibited. A flashing
display can be obtained by
applying a low frequency square
wave to the blanking input (BL).
Because the blanking input (BL)
also resets the internal display
multiplex counter, the frequency
applied to the blanking input
(BL) should be much slower than
the display multiplex rate. Finally,
dimming of the display through
the blanking input (BL) is not
recommended.
For further application informa-
tion please consult Application
Note 1026.
Optical Considerations/
Contrast Enhancement
The HPDL-1414 and HPDL-2416
displays use a precision aspheric
immersion lens to provide
excellent readability and low off-
axis distortion. For the HPDL-
1414, the aspheric lens produces
a magnified character height of
2.85 mm (0.112 in.) and a
viewing angle of ± 40°. For the
HPDL-2416, the aspheric lens
produces a magnified character
height of 4.1 mm (0.160 in.) and
a viewing angle of ± 50°. These
features provide excellent
readability at distances up to 1.5
metres (4 feet) for the HPDL-
1414 and 2 metres (6 feet) for
the HPDL-2416.
Each HPDL-1414/2416 display is
tested for luminous intensity and
marked with an intensity category
on the side of the display
package. To ensure intensity
matching for multiple package
applications, mixing intensity
categories for a given panel is not
recommended.
The HPDL-1414/2416 display is
designed to provide maximum
contrast when placed behind an
appropriate contrast enhance-
ment filter. For further informa-
tion on contrast enhancement,
see Hewlett-Packard Application
Note 1015.
Mechanical and Electrical
Considerations
The HPDL-1414/2416 are dual in-
line packages that can be stacked
horizontally and vertically to
create arrays of any size. These
displays are designed to operate
continuously between -40°C to
+85°C with a maximum of 10
segments on per digit.
During continuous operation of
all four Cursors the operating
temperature should be limited to
-40°C to +55°C. At temperatures
above +55°C, the maximum
number of Cursors illuminated
continuously should be reduced
as follows: No Cursors illumin-
ated at operating temperatures
above 75°C. One Cursor can be
illuminated continuously at
operating temperatures below
75°C. Two Cursors can be
illuminated continuously at
operating temperatures below
68°C. Three Cursors can be
illuminated continuously at
operating temperatures below
60°C.
The HPDL-1414/2416 are assem-
bled by die attaching and wire
bonding the four GaAsP/GaAs
monolithic LED chips and the
CMOS IC to a high temperature
printed circuit board. An
immersion lens is formed by
placing the PC board assembly
into a nylon lens filled with
epoxy. A plastic cap creates an
air gap to protect the CMOS IC.
Backfill epoxy environmentally
seals the display package. This
package construction provides
the display with a high tolerance
to temperature cycling.
The inputs to the CMOS IC are
protected against static discharge
and input current latchup.
However, for best results
standard CMOS handling
precautions should be used. Prior
to use, the HPDL-1414/2416
should be stored in anti-static
tubes or conductive material.
During assembly a grounded
conductive work area should be
used, and assembly personnel
should wear conductive wrist
straps. Lab coats made of
synthetic material should be
avoided since they are prone to
static charge build-up. Input
current latchup is caused when
the CMOS inputs are subjected
either to a voltage below ground
(V_IN < ground) or to a voltage
higher than V_DD (V_IN > V_DD) and
when a high current is forced into
the input. To prevent input
current latchup and ESD damage,
unused inputs should be
connected either to ground or to
V_DD. Voltages should not be
applied to the inputs until V_DD
has been applied to the display.
Transient input voltages should
be eliminated.
3-185