Heating

Infrared rays are not hot.
Contrary to the mistaken belief of many people,
the infrared rays emitted by objects such as
stoves are not hot of themselves.
So, why do they feel warm?
The answer to that question is closely related to
the nature of light.

Heating by radiation with infrared
Heat is transmitted in three ways. The first is by conduction, which requires direct contact, thesecond is by convection, in which heat is transmitted by gradually heating a medium such as air, andthe third is radiative heating, in which objects are heated by absorbing energy from radiation.
Since infrared transfers heat by radiation, direct contact is not required and thus there are noconcerns about contamination. Since radiative heat is more easily transmitted deep into matter, thesurface and interior are more easily heated than with the other types of heat transfer. Further, the lackof need for an intermediate medium means that radiative heating can be used even in a vacuum.
Also, by changing the output level, it is easy to control heating stably over any range from room
temperature to 1,000 degrees Celsius.

Halogen heater lampsHalogen heater lamps are also used insemiconductor substrate heatingsystems.

Because of these characteristics, infrared is used in heat processing systems in a wide range ofindustries, and the source on which these systems rely for infrared radiation is the halogen lamp.

Heating with flash lamps in the range from ultraviolet to visible light
Infrared is not the only type of light that can be used for heating. Flash lamps that emit radiation in
the region from infrared to visible light are also used as light sources for heating applications.
Emitting light by the same principle as the strobe lights used with cameras, high-power flash lamps
are used in combination with high capacity condensers to generate a flash of light which, during thetime it lasts, can contain the equivalent of 10 to 20 households’ energy consumption (30 kilowatts).

Flash lamp
Heating by up to 1,000 degrees Celsius injust 0.001 second.

The technology in which flash lamps are employed is one related to semiconductor manufacturing
called “flash lamp annealing.” In this process, several dozen flash lamps are used to instantaneously
raise the temperature of a thin zone at the surface of silicon wafers to 1000 degrees Celsius in just0.001 second. Viewed from another perspective, the short flash duration means that just a0.001-second deviation in the timing of flashes will result in large temperature differences at thewafer, making uniform heat processing impossible. Such precise flash timing, the power technology
required to control the depth of heating, and the optical technology required to apply this process overlarge surfaces are an area in which Ushio excels.
● Main areas of infrared application
Electronics

Heating and deposition of semiconductor and liquid crystal substrates

Office automation equipment

Fixing print and images on paper

Food processing

Cooking, drying, and temperature maintenanceForming plastics

Changing the form of plastics using heat application(such as forming plastic bottles)

Heating

Infrared heaters, Japanese kotatsu tables

New material research

New material research involving ultra-high temperatures to dissolve materials“Heating with light” The Mechanism
Radiation
Infrared light is not hot per se, but
Infrared radiation
heats by stimulating vibration of themolecules making up matter.
Reflection
This results in heat.
① Irradiation of matter with infrared.
② Light energy absorbed by matter
stimulates vibration of molecules.
Absorption③ Vibration increases collisions
between molecules, resulting inheat.
Transmission

Conduction
The phenomenon by which heattransfers from a region with higher
temperature in an object to a region
with lower temperature.

Convection
The movement of a warmer volume of
air or water which causes warming of
the entire volume.