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Most “LED” … OEM or Aftermarket … Single,
Brake/Turn Signal* Lighting that are now available in the
marketplace … will almost certainly be “EPLLA” non-compliant when
all the obvious “Non-Contributing”, “Dead”, “Transparent”, “Beyond Test
Pattern”*, “Overlapping” and “Faked” faceted or not faceted areas are
subtracted from the entire exposed outer lens area … resulting in a total
EPLLA that is much below the 11-5/8 in² area required to meet FMVSS #108
mandated “EPLLA” requirements* for over 80” wide, Single Brake & Turn
Signal uses.
*Must be within the mandated 20° Left/Right; 10° Up/Down “Test Pattern” in 7
Function Tail Light Assemblies
Remember, common “Light Emitting Diodes” (LEDs),
produce only a very directional and very small cone angle of measurable
light … usually represented by a tiny ≈20° “Conal Shaped” Output …
and that’s all.
This
limited and very directional output represents only about one percent
of all the directions of output that always emanate from the length and
circumference of the typical Incandescent Bulb Filament. This means
that over a hundred 20° Cones of Output
Light Rays are generated by the typical
#1157 or #3157 Brake/Turn Bulb Filament compared to the single
≈20° Conal Output of a typical LED!
This
“very limited and very directional, Laser-Like* Output” is why
“LEDs” draw less energy and, this is also why it takes so many
LEDs to meet the mandated “Effective Projected Luminous Lens
Area” (“EPLLA”) Requirements of FMVSS #108.
*very directional … more or less, straight out
Therefore, by
using just a few “LEDs” … where each puts out only a tiny ≈20°
Cone of EPLLA qualifying light … the typical, very compact*, 7 or 3-Function
“LED” Lamp now being sold in the marketplace will almost always fail
the mandated “EPLLA” requirements of FMVSS #108.
*as
opposed to the massive sized (and very expensive) Auto and SUV Tail Light
Assemblies.
To solve
this inherent “LED” problem, “many” LEDs must be used, and the
many used … must be properly lensed so every LED properly
projects its’ output within the mandated Test Pattern, and at the
same time, not loosing significant output because of “LED Heat
Build-Up”. It’s time everyone concerned realizes that just projecting
some Red Dots of light … even if “Photometric Compliant” …
does not guarantee a FMVSS #108 “EPLLA” Compliant Brake or Turn Lamp.
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