Datasheet

17
Window Design
To insure IrDA compliance, some
constraints on the height and
width of the window exist. The
minimum dimensions ensure that
the IrDA cone angles are met
without vignetting. The
maximum dimensions minimize
the effects of stray light. The
minimum size corresponds to a
cone angle of 30 degrees, the
maximum, to a cone angle of 60
degrees.
X is the width of the window, Y is
the height of the window, and Z is
the distance from the HSDL-3201
to the back of the window. The
distance from the center of the
LED lens to the center of the
photodiode lens is 5.1 mm. The
equations for the size of the
window are as follows:
X = 5.1 +2(Z + D) tan θ
Y = 2(Z + D) tan θ
Where θ is the required half
angle for viewing. For the IrDA
minimum, it is 15 degrees, for the
IrDA maximum it is 30 degrees.
(D is the depth of the LED image
inside the part, 3.17 mm). These
equations result in the following
tables and graphs:
Minimum and Maximum Window Sizes
Dimensions are in mm.
Depth (Z) Y min. X min. Y max. X max.
0 1.70 6.80 3.66 8.76
1 2.23 7.33 4.82 9.92
2 2.77 7.87 5.97 11.07
3 3.31 8.41 7.12 12.22
4 3.84 8.94 8.28 13.38
5 4.38 9.48 9.43 14.53
6 4.91 10.01 10.59 15.69
7 5.45 10.55 11.74 16.84
8 5.99 11.09 12.90 18.00
9 6.52 11.62 14.05 19.15
10 7.06 12.16 15.21 20.31
Window Height Y vs. Module Depth Z
Window Width X vs. Module Depth Z
Y
X
Z
WINDOW HEIGHT Y – mm
16
MODULE DEPTH Z – mm
6
48
0
2
14
010
10
26
12
8
4
ACCEPTABLE
RANGE
60° CONE
30° CONE
WINDOW WIDTH X – mm
22
MODULE DEPTH Z – mm
12
48
6
8
20
010
16
26
18
14
10
ACCEPTABLE
RANGE
60° CONE
30° CONE