Specifications

12 ExtroNews 13.2 April – June 2002
Perhaps I was fortunate. Most of my
friends didn’t have “space command” in
their homes. And, while the clicker didn’t
need batteries, we did have to replace the
springs once in a while and put up with that
motorized, ratcheting mechanical tuner.
What if we couldn’t find the clicker?
Through her own early research and
development in remote control, Mom
discovered that if she took the large soup
spoon and struck it with the paring knife
she could change channels.
Thus began the era of the remote control
in the home. In the US, most all remote
controls for TVs began as ultrasonic (above
human hearing) controls. These mechanical
controls with limited functions evolved into
electronic ultrasonic remotes with
additional functionality. Then, in the late
1970s, infrared light became the method of
choice when light emitting diodes became
available. Why infrared? What is infrared
exactly?
I Am, Therefore IR
The light emitting diode is a marvel. In
the 70s, integrated circuit (IC) development
was in its infancy. One of the curious
byproducts of activated ICs was that some
IR Control — The Invisible Frontier
TECHNICALLY SPEAKING...
by Steve Somers, Vice President of Engineering
H
ow many of you grew up like me in a house with “the clicker”?
Dad: “Steve, bring me the clicker. Perry Mason is about to start on
channel eight… oh, thanks.” <Click!> ker-chunk, ker-chunk, ker-chunk...
<Click!> ker-chunk…
portions would emit light while operating.
Researchers could see this strange light
emission under laboratory conditions
using electron microscopes. By the late
70s, semiconductor channel structures
were designed to emit light when small
voltage potentials were applied. While
quite large compared to current
fabrication technology, these silicon
channel structures translate to wide gaps,
or long wavelengths that can generate
energy in the infrared, or what we call the
IR region.
This portion of the light spectrum is
called “infrared” since it comprises the
region between visible red and the
microwave (radio) region. See Figure 1.
The infrared region is relatively wide—
extending from about 0.75 micrometers
to over 100 micrometers. The most widely
used infrared range for control is from
0.78 to 1.5 micrometers, or microns.
All objects not at 0° Kelvin (absolute
zero) emit energy in the infrared region.
Heat travels from one object to another
via radiation, convection, or conduction.
The sensation of heat is produced by
infrared energy. While conduction
Figure 1. Infrared energy resides between visible red and microwave radio.