FAQ - Light Sources

NOTE: Here is a link to our Specialty Light Source Products.

 

Voltage and Current

Please comment on how voltage and current influences filament design? 
May lamps and LEDs be operated at reduced voltages or currents than those specified?

LEDs

What is the spectral band width of LEDs?
Is packaging important for LED performance?
Explain LED lens types: Clear, Translucent and Diffused.
Can you provide cross references to your LEDs?

Lamps

What is a Halogen Lamp? 
Explain dichroic halogen lamp reflectors both parabolic and ellipsoidal.
What is the purpose of a lens-end lamp?
Which lamps and LEDs are recommended for fiberoptic applications?
What is the spectral band width of tungsten halogen lamps?
Which lamps are recommended as low cost infrared sources for gas sensor applications?
How do I select a halogen lamp holder for a known halogen lamp?
Will ILT Light Sources design a new lamp for a customer application?
Will ILT Light Sources design sub-assemblies?
What is "UV Block"?
What is a filament and what are the filament description codes?

Light Measurement Terms

Explain some of the various light measurement terms.

Distributors, Pricing, Ordering

Does ILT Light Sources have any distributors?
How can I get pricing for your parts?
What is your minimum order quantity?

 

 

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Q. Please comment on how voltage and current influences filament design?
A. When designing a filament, voltage dictates length of tungsten wire required and current determines the diameter of that wire. Consequently, a low voltage and higher current filament results in a more rugged filament construction.

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Q. May lamps and LEDs be operated at reduced voltages or currents than those specified?
A. Yes. However there will be a reduction in light output and an increase in expected life.

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Q. What is the spectral band width of LEDs?
A. LEDs are narrow band emitters. Typically, the bandwidth is 30nm wide. ILT Light Sources LEDs have spectral peaks from 430nm up to 700nm in the visible light range and 880nm and 940nm in the near infrared range.

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Q. Is packaging important for LED performance?
A. Most definitely. The T-1 3/4 package optimizes LED performance with its efficient internal reflector and integral lens. As the package becomes smaller, efficiencies are lost. Most SMT packages add little to LED performance except for our new E70 type package.

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Q. Explain LED lens types: Clear, Translucent and Diffused.
A. Clear has the appearance of window glass and results in a narrow viewing angle. Translucent has identical properties to clear, however does have small amount of color. Diffused is normally with color and more dense providing a wide viewing angle.

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Q. Can you provide cross references to your LEDs?

A. Yes, if you are using another LED manufacturer's product, just provide the part number of the other LED manufacturer and our engineers will be more than happy to assist you. It will help to expedite the process if you can also provide us with the specifications of the target LEDs.

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Q. What is a Halogen Lamp?

A. A halogen lamp is a tungsten filament lamp that is filled with a small amount of the halogen gas bromine. When the lamp is energized the evaporating tungsten molecules combine with halogen vapor to form tungsten bromine. This tungsten bromine will not condense on the lamp wall when the wall temperature is between 250° and 325° C. The result being a lamp envelope that does not blacken during life.

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Q. Explain dichroic halogen lamp reflectors both parabolic and ellipsoidal.
A. The dichroic reflector reflects visible light and absorbs the infrared. Ellipsoidal reflectors focus the light to a point. Parabolic reflectors do not focus but offer a parallel beam.

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Q. What is the purpose of a lens-end lamp?
A. To optimize light output by directing it into a useful direction. Many times a 10 - 20 watt non lens lamp can be replaced by a 1 watt lens-end lamp.

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Q. Which lamps and LEDs are recommended for fiberoptic applications?
A. ILT Light Sources recommends lamps that can direct and focus light into fiber optic wire bundles. For example: lamps matched with MR3, MR4, and MR8 reflectors, lens-end halogen lamps, and LEDs are some candidates for fiber optic applications.

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Q. What is the spectral band width of tungsten halogen lamps?
A. These lamps provide broad band emission ranging from the ultraviolet on into the infrared.

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Q. Which lamps are recommended as low cost infrared sources for gas sensor applications?
A. New lamps have been developed with thin glass walls and compact double coiled tungsten CC-6 filaments enhancing IR output. Please see miniature visible-infrared lamps.

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Q. How do I select a halogen lamp holder for a known halogen lamp?
A. All halogen lamps have a configuration designation as: G4, GZ4, G6.35, GY6.36, GZ6.35, GX5.3, GY9.5. Each of our lamp holders also include this designation. For example a halogen with a G4 designation will fit into any of our holders also designated G4.

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Q. Will ILT Light Sources design a new lamp for a customer application?
A. ILT Light Sources looks forward to providing light sources that fulfill OEM design requirements. If an existing ILT Light Sources light sources does not meet your specifications, our experienced engineering team can assist with specifications for a custom solution. Please contact ILT Light Sources for assistance.

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Q. Will ILT Light Sources design sub-assemblies?
A. ILT Light Sources can furnish sub-assemblies per your requirements. ILT Light Sources lamps can be customized for specific applications such as: pre-focused lamp/reflectors or lamp, lamp holder, wiring/connector assemblies. The sub-assemblies can be built, tested, and ready for easy installation into your OEM products. Call ILT Light Sources for assistance.

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Q. What is "UV Block"?
A. Most halogen lamps manufactured for general lighting applications now include "UV Block". "UV Block" requires a special quartz envelope designed to cancel the ultraviolet output of a halogen lamp. Most of our halogen lamps are manufactured from clear quartz and do not include "UV Block". ILT halogen lamp part numbers starting with "GTL-OS" are UV blocking.

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Q. What is a filament and what are the filament description codes?

A. A filament is a thin metal wire purposely positioned inside a lamp bulb, that generates radiation in the visible, infrared and ultraviolet ranges when electrical current is passed through it. Tungsten material is often used, as it has great tensile strength, is very durable, and can be heated very near its melting point without evaporating rapidly. Lamp filaments are offered in a variety of designs optimized for specific applications.

A filament description consists of a prefix letter, to indicate whether the wire is straight or coiled, followed by a number to indicate the arrangement of the filament on the supports.


Prefix letters are usually one of three options:
  • S – Straight, there is no coil to the filament
  • C – Coiled, the filament is wound into a helical coil
  • CC – Coiled Coiled, the helical coiled filament is wound again into another helical coil.

Q. Explain some of the various light measurement terms (see also the chart image below).

Photometry - The science of measurement of light intensity, where "light" refers to the total integrated range of radiation to which the eye is sensitive.

Radiometry - The science of radiation measurement. Which is the detection and measurement of radiant energy.

Luminous Intensity - Luminous flux emitted by a source in a given range of directions. The unit of measure is the lumen/steradian, known as the candela.

Lumen - The unit of luminous flux equal to the luminous flux emitted per unit solid angle by a standard point source having a luminous intensity of one candela.

Mean Spherical Candlepower (MSCP) - The MSCP rating of a lamp is measured at the design voltage and is the total amount of light given off from a light source in ALL directions. One MSCP is equivalent to all the light emitted from all directions of one standard spermaceti candle. Mean spherical candlepower is the generally accepted method of rating the total light output of miniature lamps. 1 MSCP equals 12.57 (4 pi) lumens


Lux - The unit of luminous incidence or illuminance, equal to one lumen per square meter.

Candela - The unit of luminous intensity. It is defined as one-sixtieth the normal intensity of one square centimeter of a black body at the solidification temperature of platinum. A point source of one candela intensity radiates one lumen into a solid angle of one steradian.

Steradian - The unit of a solid angle substended at the center of a sphere by an area on its surface equivalent to the square of the radius; the unit of solid angular measurement.

Footcandle - The unit of illuminance equal to one lumen per square foot.

Footlambert - The unit of illuminance equal to 1/p candela per square foot.

Nit - Unit of measurement of brightness (luminance) equal to one candle per square meter. One Nit equals 0.094 foot lambert.
Reference: The Photonics Dictionary (1994)

Reference: Lighting Handbook, Reference & Applications, 8th Edition, page 29

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Q. Does ILT Light Source have any distributors?
A. ILT Light Sources does not use distributors. If you would like more information regarding our products, or to place an order, you may contact us directly at our company headquarters either by phone, fax, or e-mail. See our Contact Us page for details.

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Q. How can I get pricing for your parts?
A. You may get the price for any of our products by contacting us by either phone ,fax, or email. Our pricing is structured to provide for OEM volume discounts.

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Q. What is your minimum order quantity?
A. The minimum order quantity for any product is determined by the package size for that item. Please contact us for details.

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