User Manual
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Figure 13a. PS Output vs. Distance at LDRIVE = 100 mA, PPULSE = 8, PGAIN =
4x, PPLEN = 8 ms, LED_BOOST = 100% with various objects. No glass in front
of the module
Figure 13a. PS Output vs. Distance at LDRIVE = 100 mA, PGAIN = 4x, PPLEN
= 8 ms, LED_BOOST = 100% with various pulses. No glass in front of the
module
Optical and Mechanical Design Consideration
Optical Transmittance of Window Material
Windows with an IR transmittance of at least 80% (mea-
sured at 950nm) are recommended for use with the APDS-
9960. Note that for aesthetic reasons, the window’s mate-
rial could be tinted or coated with a dark ink. For example,
a 20% (measured at 550nm) visible transmittance window
with 80% IR transmittance can be used. Such a coating
would have transmittance spectral response with low
transmittance within the visible range and a high trans-
mittance in the infrared range. This low to high trans-
mittance transition wavelength should be shorter than
650nm to minimize crosstalk.
Examples of recommended window material part
numbers are shown in the table below.
Table 1. Recommended Plastic Materials
Material number
Visible light
transmission Refractive index
Makrolon LQ2647 87% 1.587
Makrolon LQ3147 87% 1.587
Makrolon LQ3187 85% 1.587
Lexan OQ92S 88 - 90% -
Lexan OQ4120R 88 - 90% 1.586
Lexan OQ4320R 88 - 90% 1.586
Crosstalk and Window Air Gap
Crosstalk is PS or Gesture output caused by unwanted LED
IR rays reection without any object present. To control
crosstalk when operating the sensor in gesture mode, we
recommend that a rubber isolating barrier be tted over
the sensor. A possible design is shown in Figure 12.
The rubber consists of two cylindrical openings, one for
the LED and the other for the Photodetector. The window
thickness should not be more than 1mm. When assem-
bled the rubber barrier should form a good optical seal to
the bottom of the window.
Recommended dimensions of the barrier are:
Air Gap
PD Opening
Diameter
LED Opening
Diameter
1mm 2mm 1.5mm
Residual crosstalk of the Up, Down, Left and Right Gesture
output may be reduced by writing to the individual
GOFFSET registers. Such calibration is necessary to ensure
good gesture sensing performance.
Figure 12. Rubber Barrier
PD Opening Diameter
Optical
Barrier
Air Gap or Barrier Height
LED Opening
Diameter
Window
Thickness
0
50
100
150
200
250
300
0 5 10 15
PS Count
Distance (cm)
0
50
100
150
200
250
300
PS Count
90% Kodak Card
18% Kodak Card
Opteka Black Card
4 9 143 8 132 7 121 6 11
4P
8P
0 5 10 15
Distance (cm)
4 9 143 8 132 7 121 6 11