is a "Light Pipe"?
Light pipes are
semi-transparent parts that are used to conduct light from a source
(Typically an LED of an
electronic device) to almost any desired position on the product.
Since LEDs (Light
Emitting Diodes) are most economically mounted directly on the
PCB (Circuit Board of
the product), light pipes are used in situations where the output
position desired for an
indicator is too remote to allow simply viewing the LED directly.
You probably need to
look no further than your own computer printer to find an example.
Light pipes transmit and
reflect/refract the light internally within their
Unless the geometry is very
simple (a strait tube), thorough knowledge of light transmission,
texture and wavelength effects is required to develop efficient designs.
requirement to make such a part easily moldable without destroying
the desired optical
qualities can complicate this challenge even further.
is a "Back Light"?
The type of back light
referred to here is used to conduct light from a source
(Perhaps an array of
LEDs) and disperse the light evenly beneath the surface of an
LCD (Liquid Crystal
Display) to allow viewing the display in low-light conditions.
Such separate back
lights are an economical and necessary option for smaller,
custom-sized LCDs that
do not have conventional backlight options available.
The design requirements
are similar to a very large light pipe. However because the desired
effect is to illuminate
a relatively large area very
the design challenge is greater still.
3D computer simulation is the method I use to sort through the
Followed usually by prototyping to verify the results in the real world.
I use the advanced Trace
simulation software for the most difficult work.