hsdl-3201 LiteOn Technology Corp., hsdl-3201 Datasheet - Page 18

• Manufacturer Part Number: hsdl-3201
• Description: Irda Data 1.4 Low Power Compliant 115.2 Kb/s Infrared Transceiver
• Manufacturer: LiteOn Technology Corp.

Shape of the Window
From an optics standpoint, the
window should be flat. This ensures
that the window will not alter either
the radiation pattern of the LED, or
the receive pattern of the photodiode.
If the window must be curved for
mechanical design reasons, place a
curve on the back side of the window
that has the same radius as the front
side. While this will not completely
eliminate the lens effect of the front
curved surface, it will reduce the
effects. The amount of change in the
radiation pattern is dependent upon
the material chosen for the window,
the radius of the front and back
curves, and the distance from the
back surface to the transceiver. Once
these items are known, a lens design
can be made which will eliminate the
effect of the front surface curve.
The following drawings show the
effects of a curved window on the
radiation pattern. In all cases, the
center thickness of the window is 1.5
mm, the window is made of
polycarbonate plastic, and the
distance from the transceiver to the
back surface of the window is 3 mm.
18
Flat Window
(First choice)
Curved Front, Flat Back
(Do not use)
Curved Front and Back
(Second choice)