Uneven SEG lighting needs a layout check, not just more wattage. Match the LED optics, source-to-fabric distance and printed fabric, then test the complete frame.
Diagnose the pattern
Bright dots near LEDs suggest insufficient mixing distance or unsuitable spacing. A dark center can indicate that edge light does not reach far enough. Dark corners may come from the layout, obstructing profiles or the graphic itself. First check that every bar is powered and that the fabric is correctly tensioned.
Choose by optical design
Direct backlighting places LEDs behind the graphic; edge lighting directs light inward from the frame perimeter. Both can work. A plug-in connector does not identify the optical type, and four-side edge lighting is not automatically better than a tested opposing-edge layout.
Test before changing the full system
Measure internal width, height and depth, plus the actual distance from LEDs to fabric. Record the lens direction, spacing, diffuser and fabric specification. Test a full-size sample with the final print; plain white fabric alone cannot reveal all print-related differences. Change one variable at a time and inspect the center, edges and corners under the intended viewing conditions.
Check the electrical layout
Keep voltage, polarity and connectors compatible. Size the driver for total load according to its instructions; verify permitted bars per run and cable ratings. Disconnect power before moving or replacing bars. Adding LEDs can exceed the electrical limit without fixing the optical problem.
A product example, not a universal spacing rule
The 14W edge-lit bar is DC24V, 313 × 24 × 16mm including the lens, with a 10°×40° asymmetric beam. These figures help check fit and lens orientation; they do not establish a universal frame depth or bar spacing. Choose one fixed CCT range and test the chosen layout.
How many bars do I need?
There is no reliable bar-per-centimeter rule for every SEG frame. Send internal dimensions, a cross-section drawing and the final fabric specification for a layout proposal. Confirm uniformity on a sample before ordering the full production quantity.
14W edge-lit LED bar · Ask about a layout
Technical background: LEDVANCE distinguishes direct and side-emitting backlighting.