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Light Lines

FTI manufactures standard light lines from .125″ to over 4 feet in length. Also shown next to the light line is the optional cylindrical lens, which can increase intensity by a factor of 10.

FTI standard light line with optional cylindrical lens
FTI standard light line with optional cylindrical lens

Conversion of an optical path from a spot to a line is highly desirable in many scanning applications. It allows a photo detector with a round or square active area to receive input from a long linear array.

In machine vision lighting, an inexpensive projector bulb can illuminate the entire width of a document or web. Light lines are also used frequently to “pick-up” scattered or reflecting light from a laser and rotating mirror combinations.

FTI’s concentrates its effort designing and manufacturing custom lines. However, FTI also manufactures standard Light Lines in a wide variety of sizes and shapes, with the following features:

  • Light line lengths of .125″ (3mm) or less up to lines 4 feet (122cm) long.
  • Excellent fiber packing and alignment using proprietary manufacturing techniques, compares favorably with “wound” lines in quality without associated cost.
  • The standard bundle length of 40″ (1M) is suitable for most applications.
  • Fixture holes in the all aluminum, black anodized body assist in mounting.
  • Black anodized aluminum adapter is attached to the PVC covered metal sheathing for durability and long term performance.
  • Ends of the fiber line are flush with the housing.

Light Line Design Considerations

To optimize the performance of a Light Line as emitter or receiver, it’s important to match the active area of the line to the active area of the lamp’s focal spot or the detector being used. The usual method of design begins by describing the desired line length. Then, the optimal spot size of the lamp or area of the photo detector is identified, and a line width is calculated to work best with the setup.

To ensure consistent performance, the fiber nearer the spot (proximal) end should be randomized to minimize inconsistencies of the lamp or detector, and the fiber at the line (distal) end should be parallel, tightly nested and uniformly placed to focus the output beam, minimize output skew, and maintain uniformity.

FTI uses a unique, proprietary method of creating light lines, resulting in a repeatable, high quality, cost effective product.

Occasionally an application will require more power from the line end than the device at the spot end can output. In this case, FTI will manufacture the line using two (or more) inputs with the fiber from both inputs uniformly dispersed throughout the line, maintaining consistent energy distribution. Each input disperses light energy along the entire length of the line.

Sizing Guidelines for our Light Lines

Try to select a line length longer than the area you are inspecting; all Light Lines experience light fall-off at each end.

For web scanning applications, assuming a focal spot diameter of .55″, 1 input for every 16″ (.4M) of line will create a line width of about .015″ (.38mm) – an area most traditional lamps fill with a focused spot. If you’re using a strobe, inputs with an active diameter of up to .8″ (20mm) could be used, so the line length per input can be doubled, (or the power per inch can be increased to improve processing speed and accuracy).

Of course, your particular application is the overriding determining factor, and your goal should be to optimize line performance, using as little fiber (and the fewest number of inputs) as possible to minimize cost.

To ensure effective application, we work with you to determine exactly what design will best suit your needs. Then, we’ll help determine how uniform the response must be across the face of the line for your use. Finally, each spot-to-line is scanned on our automatic transmission fixture to ensure compliance with the developed specification, or it’s checked in a custom test fixure you provide. A hard copy record of the results can be provided with each part shipped. You’ll know the quality of the part when you receive it.


FTI manufactures light lines in multiple configurations and shapes. Dual, triple and quad (or more) heads, unique housing/fixturing shapes and sizes, bundles of varying lengths, fiber of various types, and line widths of varying sizes can be produced to your specifications or one we develop for you. Finally, high heat, vacuum or pressure applications require special consideration.

FTI Light Lines

P/NLine LengthLine WidthBundle LengthView Diagram
FTISL16854-22" (50mm).035" (.9mm)40" (1M)
FTISL16854-66" (150mm).032" (.8mm)40" (1M)
FTISL16854-1010" (254mm).020" (.5mm)40" (1M)
FTISL16854-1616" (406mm).012" (.3mm)40" (1M)
FTISL16854-2424" (610mm).020" (.5mm)40" (1M) *2
FTISL16854-4848" (1.22M).015"(.38mm)40" (1M) *3
FTIDL16855-66" (150mm) Dual.020" (.5mm) 30" (762mm) legs;
18" (457mm) common.

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