HSDL-3203 Datasheet, PDF (16/19 Pages) Agilent(Hewlett-Packard) – Small Profile Package IrDA Data Compliant Low Power 115.2 kbit/s Infrared Transceiver

Appendix D: Optical port dimensions from the HSDL-3203 to the back the above equation. Z' is defined
for HSDL-3203:
of the window. The distance from as:
To ensure 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˚ and the maximum size corre-
sponds to a cone angle of 60˚.
the center of the LED lens to the
center of the photodiode lens, K,
is 5.1 mm. The equations for
computing the window dimen-
sions are as follows:
X = K + 2*(Z + D)*tanA
Y = 2*(Z + D)*tanA
The above equations assume that
the thickness of the window is
negligible compared to the dis-
Z' = Z + t/n
where ‘t’ is the thickness of the
window and ‘n’ is the refractive
index of the window material.
The depth of the LED image in-
side the HSDL-3203, D, is
3.17 mm. ‘A’ is the required half
angle for viewing. For IrDA com-
pliance, the minimum is 15˚ and
In the figure below, X is the width ^{tance of the module from the}
the maximum is 30˚. Assuming
of the window, Y is the height of ^{back of the window (Z). If they}
the thickness of the window to be
the window, and Z is the distance ^{are comparable, Z' replaces Z in}
negligible, the equations result in
OPAQUE
MATERIAL
IR TRANSPARENT WINDOW
;;;;;;;; _Z
;;;;;^;_{;;;;;;;;;;;;;;;;;;; X}
IR TRANSPARENT
;; ^;;;;;^;; ^WINDOW
K
the following tables and graphs.
OPAQUE
MATERIAL
Z
A
D
16