Hotspots in an LED light box, the visible bright points where individual LEDs show through the display face as distinct concentrations of light, are caused by insufficient separation or diffusion between the LED source and the display surface. They are one of the clearest visual indicators of a low-quality unit and cannot be resolved without addressing the root cause.
Why hotspots occur
The most common cause is too little depth between the LED strip and the diffusion panel. LEDs are point light sources. At close range, they produce a focused beam rather than even illumination. For the light to spread into uniform coverage, it needs sufficient distance to travel before hitting the diffusion surface. Units designed to be very thin often compromise this distance, particularly in back-lit formats where the space between the LEDs and the face is compressed.
A secondary cause is the quality of the diffusion material itself. A single acrylic sheet with no treatment does not diffuse effectively. Proper diffusion requires a dedicated diffuser sheet, a sandblasted or frosted acrylic face, or a combination of both. This is why Boardsy units including the LED Cube Light Box use commercial-grade diffusion specification rather than single-sheet panels.
What you can do about hotspots in an existing unit
Check whether the diffusion panel is replaceable. In some units, adding or upgrading to a higher-density diffuser sheet resolves the problem without replacing the whole unit. Reduce the brightness output: hotspots are less visible at lower brightness levels because the contrast between bright points and the surrounding area decreases. If the unit has a depth of less than 25mm between the LEDs and the face in a back-lit configuration, the problem is structural and cannot be resolved without a different unit.
Boardsy’s LED Bench Light Box and LED Cube Light Box use commercial-grade diffusion panels and frame depths designed to produce even illumination. Contact the team if you need to replace a problematic existing display.