Frequently
Asked Questions (FAQs)
FAQs
for Small Diameter (2.0 - 8.0mm)
Cold Cathode Fluorescent Lamps (CCFLs)
Q.
Do small diameter fluorescent lamps get hot?
A. When a 2.6mm diameter CCFL
is operated at the specified drive current of 6mArms, the ends
near the electrodes will be approximately 50° C above the
ambient temperature. The body will be approximately 25° to
30° C above ambient.
Q.
What is the effect of lamp length or diameter on brightness?
A. Using the same drive current,
the surface intensity of the smaller diameter lamp will be greater.
Longer lamp lengths of the same diameter, however, have greater
total light output.
Q..
What are the preferred methods of mounting small diameter fluorescent
lamps?
A. Any method that does not
put stress on the glass envelope and/or the lead-to-glass seal
on the lamp end is acceptable. Most common methods are to solder
the leads (with a strain relief bend) directly into a PC board,
or to secure the lamp ends with a custom silicon end cap.
Q.
Can small diameter fluorescent lamps be dimmed?
A. Yes. The dimming range
is predominantly a function of the inverter.
Q.
What type/size wire is needed for small diameter fluorescent lamps?
A. The wire must have an insulation
specified at, or above, the electrical characteristics of the
lamp. Typically, small gauge 22 - 26 AWG wire is acceptable.
Q.
How can I increase lamp brightness?
A. Lamp brightness may be
increased by increasing the drive, or arc, current. However, increased
arc current will shorten lamp life and may shift the output spectrum.
Q.
Are small diameter fluorescent lamps approved to UL, CSA, TUV,
VDE or other safety standards?
A. Safety agency approvals
have not been sought by LCD Lighting. Most companies obtain their
own agency approval at the system level.
Q.
How much mercury is contained in small diameter fluorescent lamps?
A. This varies by lamp diameter,
typically 3mg for 3mm diameter to 10mg for diameters larger than
9mm.
Q.
Will small diameter fluorescent lamps work at cold ambient temperatures?
A. Yes. However, the lower
the temperature, the lower the light output and the higher the
required starting voltage. We recommend using lamp heaters in
cold ambient conditions.
Q.
How long should I expect small diameter fluorescent lamps to last?
A. Typically, 5,000 to 30,000
hours is achievable when the lamp is operated within specification
parameters. Lamp life is stated as the point at when the lamp
provides less than 50% of its initial output.
Q.
How much of the lamp's overall length is actually lit?
A. The entire length gives
off illumination, except for 8 to 10mm at each end.
Q.
Are special or custom fluorescent lamps (i.e., non-standard colors,
shapes or sizes) available?
A. Special colors and/or lamp
configurations are our specialty. However, minimum order quantities
and set-up charges would likely be required.
Q.
Are there any limits on lamp length for small diameter fluorescent
lamps?
A. The limit is dependent
upon the diameter of the lamp and the availability of an inverter
to properly drive the lamp. Typically, the ranges of straight
lamp lengths are from 25mm to 450mm long. Longer lengths are available
in non-straight, such as U-shape or M-shape, configurations.
FAQs
for Small Diameter (2.0 - 8.0mm)
Cold Cathode Fluorescent Lamp (CCFL) Inverters
Q.
Can I run more than two lamps on a single inverter?
A. Yes, it is possible to
run multiple lamps on a single inverter. To obtain optimum performance,
however, advise the inverter manufacturer to determine if inverter
modifications will be required.
Q.
How far from the lamp can I position the inverter?
A. This is greatly dependent
upon the lamp/inverter combination and the proximity to a ground
plane. It is best to consult with the inverter manufacturer to
optimize the lamp-inverter connection.
Q.
Can I power fluorescent lamps directly from the wall outlet?
A. No! You must use a properly
matched inverter. All lamp specifications and operating characteristics
are based on being driven with an appropriate inverter.
Q.
Can I be shocked by the inverter or the fluorescent lamp?
A. Yes! Although current is
low, the inverter output can exceed 1000 volts. Proper precautions
should be observed when operating these lamps.
Q.
Does the fluorescent lamp/inverter produce EMI/RFI?
A. The lamp/inverter combine
to produce some RF emission. It may be necessary to shield the
inverter after determining the results of system testing.
FAQs
for Large Diameter (8.0 - 38mm) Hot Cathode and
Cold Cathode Fluorescent Lamps (HCFLs & CCFLs)
For
questions concerning HCFLs and CCFLs, please contact Rich Webster
at (203) 795-1520 x-3163 or rwebster@LCDL.com
FAQs
about Custom Colors
Q.
What do you mean by "Color Temperature"?
A. The color temperature of
light refers to the temperature to which one would have to heat
a "black body" source to produce light of similar spectral
characteristics. Color Temperature is expressed in degrees Kelvin
(K). Low color temperature implies warmer (more yellow/red) light
while high color temperature implies a colder (more blue) light.
Moreover, the "color temperature" of a lamp refers to
how reddish, greenish or bluish the lamp appears. If the lamp
appears reddish, it has a lower color temperature (e.g., 2500K-3000K)
and is considered to be "warm" in appearance. If the
lamp appears to be bluish, it has a higher color temperature (e.g.,
4000K-4500K) and is considered to be "cool" in appearance.
Q.
What is "Color Rendering Index"?
A. The Color Rendering Index,
or CRI, is a term in photometry used to describe the effect of
a light source on how well it renders colors. In essence, the
Color Rendering Index (CRI) is a numerical system that rates the
"color rendering" ability of fluorescent light in comparison
with natural daylight. If a lamp has a low color rendering index
of 50, it does not render colors very well. If, however, the lamp
has a color rendering index of 80 - 95, its ability to render
colors is thought to be very good to excellent. A CRI of 100 is
considered natural daylight and is assigned to the sun itself.
Q.
What is the Color Temperature (Kelvin) of fluorescent lamps?
A. Color temperature depends
upon the phosphor used to manufacture the lamps. The most common
industry lamp phosphors produce the following color temperatures.
Phosphor
Type Color Temperature
(Warm White) 2800° K to 3200° K
(Day Light) 6200° K to 6800° K
(Cool White) 4000° K to 4500° K
Q.
What is the best way to specify the "color" of fluorescent
lamps?
A. Fluorescent lamp "color"
is best identified through the use of coordinates on the CIE 1931
20 or 1976 UCS Chromaticity Diagrams, x, y or u', v', respectively.
