C haptEr 9 design Environments and systems
356
common lighting wire, strip, and surface devices based on electroluminescent technologies, a voltage input provides an energy
stimulus that causes light to be emitted. A high electric field causes
electrons to move through the phosphor and hit ionized impurities scattered through the phosphor that in turn become excited
and emit light photons of specific color and frequency. In a typical
application, such as the backlighting of an alarm clock, phosphors
are bonded as surfaces onto substrate materials. Lighting devices
based on electroluminescent technologies provide uniformly bright
surfaces. They generate little heat and are energy efficient. Various
varieties of substrates (polymeric, glass, other) can be used as long
as an electric field can be generated. Various sizes and shapes of
“glowing” wires, strips, or surfaces can be obtained. Depending on
surface shape, different manufacturing processes (e.g., printer-based
or spin coatings) can be used to fabricate lighting devices based
on these technologies. Before the advent of LEDs, which also use
phosphors, these technologies seemed poised to provide the next
generation of lighting solutions in products and buildings, but the
several advantages of LEDs soon caused them to become dominant.
Nonetheless, they still form a highly attractive lighting solution for
many applications due to their simplicity, reliability, and uniform
light quality.
Considerable work has been done on creating “nanophosphors”
based on nanoparticles that have unique physical and chemical
properties as compared to normal phosphors. These properties are
highly dependent on particle size and shape, including their emission characteristics. Of particular importance here is that the emission bands of emitted light can potentially be finely tuned. These
nanophosphors can be synthesized by either physical methods
such as molecular beam epitaxy, sputtering, or the like or chemical methods such as sol-gel, colloidal, and so on (see Chapter 8).
Emission efficiencies can be dramatically improved compared to
normal phosphors. Luminescent semiconductor nano crystals
have been widely researched because of their unique optical
properties.
Lighting devices based on nanophosphors can potentially become
much more efficient than is currently the case. One practical
approach is to build on existing phosphor-based lighting technologies and enhance them via nanophosphors. Various kinds of
coatings with nanophosphors that could be used directly or in conjunction with traditional phosphors are under development. These
include existing LED technologies as well (see the discussion on
LEDs that follows).
356
common lighting wire, strip, and surface devices based on electroluminescent technologies, a voltage input provides an energy
stimulus that causes light to be emitted. A high electric field causes
electrons to move through the phosphor and hit ionized impurities scattered through the phosphor that in turn become excited
and emit light photons of specific color and frequency. In a typical
application, such as the backlighting of an alarm clock, phosphors
are bonded as surfaces onto substrate materials. Lighting devices
based on electroluminescent technologies provide uniformly bright
surfaces. They generate little heat and are energy efficient. Various
varieties of substrates (polymeric, glass, other) can be used as long
as an electric field can be generated. Various sizes and shapes of
“glowing” wires, strips, or surfaces can be obtained. Depending on
surface shape, different manufacturing processes (e.g., printer-based
or spin coatings) can be used to fabricate lighting devices based
on these technologies. Before the advent of LEDs, which also use
phosphors, these technologies seemed poised to provide the next
generation of lighting solutions in products and buildings, but the
several advantages of LEDs soon caused them to become dominant.
Nonetheless, they still form a highly attractive lighting solution for
many applications due to their simplicity, reliability, and uniform
light quality.
Considerable work has been done on creating “nanophosphors”
based on nanoparticles that have unique physical and chemical
properties as compared to normal phosphors. These properties are
highly dependent on particle size and shape, including their emission characteristics. Of particular importance here is that the emission bands of emitted light can potentially be finely tuned. These
nanophosphors can be synthesized by either physical methods
such as molecular beam epitaxy, sputtering, or the like or chemical methods such as sol-gel, colloidal, and so on (see Chapter 8).
Emission efficiencies can be dramatically improved compared to
normal phosphors. Luminescent semiconductor nano crystals
have been widely researched because of their unique optical
properties.
Lighting devices based on nanophosphors can potentially become
much more efficient than is currently the case. One practical
approach is to build on existing phosphor-based lighting technologies and enhance them via nanophosphors. Various kinds of
coatings with nanophosphors that could be used directly or in conjunction with traditional phosphors are under development. These
include existing LED technologies as well (see the discussion on
LEDs that follows).