Dike-Edge COB LED Strip: Advantages, Limitations & Beam-Angle Changes (vs. Traditional COB)

COB LED strips (Chip On Board) have become a mainstream choice for under-cabinet lighting, linear recessed channels, and commercial display applications thanks to their dot-free continuous light and soft, premium appearance. Within the COB family, dike-edge (dam-edge) COB strips are increasingly adopted—not simply because of a different coating, but because a raised edge structure provides stronger control over encapsulation boundaries and the light path. The result is a cleaner emitting surface and more controllable side spill.

This article covers structural differences, pros and cons, recommended applications, common installation issues, and—most importantly—beam-angle changes (Beam Angle / Field Angle) to support practical selection and installation decisions.

Contents

• 1. What Is a Dike-Edge COB and How Is It Different?
• 2. Advantages of Dike-Edge COB
• 3. Limitations: More Demanding on the System
• 4. Beam-Angle Changes: How Much Does It Narrow?
• 5. Application Recommendations
• 6. Common Issues & Practical Solutions
• Conclusion

1. What Is a Dike-Edge COB and How Is It Different from Traditional COB?

Traditional COB LED strips typically use a relatively flat overall coating/encapsulation process. The edges of the emitting area rely mainly on process control, so boundary consistency can be influenced by overflow, material flow, and curing variations.

A dike-edge COB LED strip introduces a “dike/dam” structure on both sides of the emitting surface (think of it as a micro barrier). During encapsulation or coating, this structure limits lateral material flow, making the emitting surface more uniform, the edges cleaner, and—to a certain extent—reducing side spill.

In one sentence: Traditional COB is like a “spread-out blanket of light,” while dike-edge COB is more like a “light panel with controlled boundaries.”

2. Advantages of Dike-Edge COB: Why It Looks More Premium and Works Better for Project Delivery

Advantage A: A more uniform emitting surface and cleaner edges

The dike-edge structure constrains the encapsulation boundary, helping reduce edge roughness and visual inconsistency caused by overflow. Linear light looks more like one continuous, clean line.

Advantage B: Better consistency for standardized project delivery

When multiple strips are installed side-by-side within the same space and the same batch is required, dike-edge COB is often easier to keep visually consistent—reducing the risk of “it looks different after installation.”

Advantage C: More friendly to surface contamination and minor abrasion (depends on materials and process)

Because the emitting gel is more “contained” within the edge boundary, fingerprints, dust, and light scuffs are less likely to affect the appearance during installation and maintenance.

Note: This does not equal an IP rating. Protection still depends on the overall system design and material matching.

3. Limitations of Dike-Edge COB: Not a Universal Upgrade—More Demanding on the System

Limitation A: Higher cost and more complex process—quality depends more on supply-chain capability

A dike-edge structure means more materials and steps. Final stability is closely tied to the factory’s encapsulation capability. Whether it is “worth it” often depends on supply-chain maturity, not just the datasheet.

Limitation B: More sensitive to heat dissipation and thermal stress (especially high power and enclosed installation)

The dike-edge plus gel participates in thermal cycling. If heat dissipation is insufficient or power density is too high, yellowing and lumen depreciation can accelerate, and encapsulation stress issues may occur.

Dike-edge COB performs best with a reasonable power level + proper aluminum profile heat sinking + controlled operating temperature system approach.

Limitation C: More limited bending and cornering

A cleaner boundary can also mean a “stiffer” structure. In small-radius bends, serpentine routing, and corner-dense cabinetry, there is a higher risk of edge irregularities, localized shadows, or reduced lifetime due to mechanical stress.

Limitation D: On-site cutting, soldering, and secondary processing are more demanding

Dike-edge COB behaves more like an engineered module. It has less tolerance for quick cuts and quick fixes. Poor cut finishing or non-standard soldering can lead to uneven edges or encapsulation damage, so installation discipline matters more.

4. Beam-Angle Changes: How Much Does Dike-Edge COB Actually “Narrow” the Light?

Many people feel dike-edge COB looks more forward-focused. That’s generally true, but it must be understood correctly: the most noticeable impact is often on the side spill boundary, not necessarily turning a “120° nominal” strip into something extremely narrow.

4.1 Two key metrics: Beam Angle vs. Field Angle (plain-English explanation)

Imagine the light distribution as a “mountain of light.” Straight ahead is the peak (100%). As you move toward the sides, intensity decreases. The industry defines angles by choosing an intensity drop level as the boundary:

• Beam Angle (50% FWHM): the total angle where intensity drops to 50% of the maximum.
  Plain meaning: how wide the “core bright zone” is (the main useful beam).
• Field Angle (10%): the total angle where intensity drops to 10% of the maximum.
  Plain meaning: how wide the “light influence/spill zone” is (how far the light still affects surroundings).

In practice, the dike-edge structure most noticeably changes the 10% Field Angle first, and the 50% Beam Angle second—because the side barrier more easily blocks weaker side light.

4.2 Typical ranges (practical reference for selection)

Typical change summary:

• 50% Beam Angle often narrows by about 5°–25°
• 10% Field Angle often narrows by about 20°–60° (main reason for “less side-wall brightness and cleaner lines”)

Important: Actual values depend on dike height/width, gel shape and refractive index, emitting surface width, and the diffuser cover used in the system. For precise parameters, use IES/LDT photometric files or a photometric test report.

5. Application Recommendations: When Dike-Edge COB Is Worth It (and When Traditional COB Is Better)

Where dike-edge COB is strongly recommended

1. Linear channels / recessed ceiling lines
   Best for sharp edges, clean lines, and consistent emitting surfaces.
2. Display cases, shop windows, shelving (high chance of direct viewing)
   Cleaner emitting surface with less edge noise helps achieve a premium look.
3. Indirect wall-wash / ceiling-wash (when you want cleaner control)
   Better-controlled side spill reduces stray reflections inside the channel.

Where traditional COB is often a better choice

1. Small-radius bends and corner-heavy routing
   Traditional COB usually adapts more easily to complex routing.
2. Under-cabinet lighting where you want to illuminate side panels/interior surfaces
   Traditional COB has more side output; dike-edge COB may feel “brighter on the countertop but darker on side surfaces.”
3. Budget-sensitive, non-standard projects with frequent on-site modifications
   Traditional COB is typically more forgiving for on-site adjustments.

6. Common Issues & Practical Solutions (for Designers and Installers)

Issue 1: Shallow channel + low-haze diffuser = “bright but harsh, not uniform”

Recommendation: Increase the optical cavity height, or choose a diffuser with more appropriate haze/transmittance to improve uniformity and softness.

Issue 2: Direct-view positions may cause more glare

Because dike-edge COB can appear more forward-focused, glare can be more noticeable without a diffuser or with poor mounting angles.
Recommendation: Use a diffuser/grille in visible areas, or optimize the mounting angle and shielding structure.

Issue 3: Dual-CCT / dimming color mixing is not as expected (“doesn’t blend” or looks “layered”)

With reduced side mixing, dike-edge COB becomes more sensitive to cavity depth, diffuser material, and driver dimming curves. In some shallow profiles, it may show less uniform mixing than traditional COB.

Recommendation: Increase mixing distance (deeper channel), improve diffusion, and use a properly matched CCT driver and dimming solution.

Conclusion: Dike-Edge COB Trades Process for Consistency—and Requires a System Approach

The value of dike-edge COB is not only “brighter” or “softer,” but stronger boundary control, more stable visual consistency, and a more project-ready delivery experience. In the right application, it clearly elevates appearance and perceived quality.

However, it also demands better heat management, profile selection, and installation discipline—so it should be selected as part of a system, not as a standalone strip.

If you would like more accurate photometric guidance for your project, we recommend confirming: channel depth, whether a diffuser is used, mounting height and viewing angle, power density, and heat-sinking conditions—so the final result remains stable and consistent.