Polycarbonate LED diffuser sheet: the three numbers that decide the look
An LED diffuser is specified by three figures — light transmission, haze, and the light-mixing distance behind the panel. Get them right and the fixture shows an even glow with no visible dots; get them wrong and you see either hotspots or a dim, milky panel. These three, not the material name, are what a lighting engineer actually needs to quote against.
Transmission versus haze — they pull against each other
Transmission is how much light gets through; haze is how much it is scattered. A clear sheet passes ~88% of light but hides nothing — every LED is a visible dot. A heavily diffusing sheet hides the dots but can drop transmission below 60%, wasting lumens and heat. The usable range for most fixtures is a diffuser passing 60–75% transmission at 90%+ haze: enough scatter to erase the dots, enough transmission to keep the fixture efficient.
| Diffuser grade | Light transmission | Haze | Best for |
|---|---|---|---|
| Light (clear-ish) | 80–86% | 50–70% | Indirect fixtures, deep cavities |
| Standard opal | 65–75% | 90–95% | General panel and troffer lighting |
| Heavy opal | 55–65% | 96–99% | Shallow fixtures, LEDs close to surface |
Mixing distance: the spec everyone forgets
The gap between the LEDs and the diffuser is what actually hides the dots. As a working rule, the LED pitch (centre-to-centre spacing) should not exceed the cavity depth — keep LED spacing ≤ the distance to the diffuser. LEDs 20 mm apart need at least 20 mm of depth behind a standard opal sheet. Less depth than that, and you move to a heavier haze grade to compensate, at the cost of transmission. Tell us the LED pitch and cavity depth and we will recommend the grade rather than guessing.
Why polycarbonate over acrylic for diffusers
Acrylic diffuses well and costs less, but it is brittle and yellows faster under continuous heat and UV. Polycarbonate takes the heat close to high-output LEDs without warping, survives handling and installation without cracking, and holds its colour longer in fixtures that run all day. For fixtures that are hard to reach or expensive to replace, the longer service life usually outweighs the material cost.
What to send for an LED diffuser quote
- Target transmission and haze, or the fixture type if you are unsure
- LED pitch and cavity depth — the two numbers that set the grade
- Sheet thickness and panel size, flat or formed
- Whether the edge is lit (edge-lit panels have different requirements)
- Operating temperature near the LEDs
Send the fixture geometry and we will match a diffuser grade to it, with transmission and haze figures stated, before you commit to a sample run.
Why Choose Our PC LED Diffuser Sheets?
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Zero HotspotsEliminate pixelation for uniform illumination. |
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UL94 V-0 SafetyCertified flame retardant for public projects. |
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Heat StabilityStable up to 120°C, outperforming Acrylic. |
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High Trans.Light transmission from 60% up to 90%. |
Pro Tip: Polycarbonate diffusers are 250x more impact-resistant than glass, making them the safest choice for vandal-proof lighting.
Technical Specifications
Standard and customizable optical properties for professional LED lighting applications.
| Properties | Testing Method | Values & Data |
|---|---|---|
| Material | - | Optical Grade Polycarbonate (PC) |
| Light Transmission | ASTM D1003 | 60% - 90% (Customizable) |
| Haze / Diffusion Degree | ASTM D1003 | 98% - 99.5% |
| Fire Retardancy | UL 94 | V-0 / V-2 / HB |
| Heat Deflection Temp. | ASTM D648 | 120°C - 135°C |
| Thickness Range | Micrometer | 0.5mm - 5.0mm |
| Impact Strength | ISO 179/1eA | 850 J/m (Virtually Unbreakable) |
Need a Detailed TDS?
Download the full Technical Data Sheet for complete optical and physical properties.
Core Applications for LED Diffuser Sheets
Engineered for optical precision, our PC diffusers are the preferred choice for high-end lighting projects globally.
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FAQ: LED Light Diffuser Solutions
Everything you need to know about selecting the right optical polycarbonate sheets.
Q: Is Polycarbonate better than Acrylic (PMMA) for LED diffusion?
A: Yes, for most industrial and commercial applications. While Acrylic has slightly higher clarity, Polycarbonate (PC) offers far superior heat resistance (up to 120°C) and is virtually unbreakable (250x stronger than glass). This makes PC the safer choice for high-power LED fixtures and public environments.
Q: How do I choose the right light transmission rate?
A: It depends on the distance between the LEDs and the diffuser. For slim profiles, a lower transmission (60-70%) is better to hide hotspots. For deep fixtures, higher transmission (80-90%) can be used to maximize brightness while maintaining a uniform "line of light."
Q: Do you provide custom cut-to-size and CNC services?
A: Absolutely. We provide professional CNC routing and laser cutting services. Whether you need circular discs for downlights or complex shapes for architectural fixtures, we can provide precision-cut pieces based on your CAD drawings.
Q: Are your LED diffuser sheets fire-rated?
A: Yes. Our optical grade polycarbonate is available with UL94 V-0 or V-2 fire ratings. This is a critical requirement for safety compliance in commercial buildings, airports, and industrial facilities.
Still have technical questions? Contact our engineering team for a detailed consultation.
PC LED Diffuser Sheet for Fixture Projects
Bakway can manufacture PC LED diffuser sheet for lighting fixtures and panels. The selected grade is confirmed from the LED type and pitch, source-to-sheet distance, required uniformity, glare or hotspot tolerance, colour, thickness and dimensions.
Bakway can manufacture market-available diffuser-sheet grades. Bakway can manufacture to this specification; final availability, compliance and order details are confirmed against the project specification.
The minimum order quantity is 1 pallet; configuration varies by product. For texture or appearance choices, see the textured and light-diffusing sheet options.
PC LED Diffuser Plate Specifications
| Thickness | Light transmission | Haze | Typical use |
|---|---|---|---|
| 0.8–1.2 mm film | 85–92% | 60–75% | LED strip covers, signage |
| 1.5–2.0 mm sheet | 75–88% | 75–90% | Panel lights, troffers |
| 2.0–3.0 mm sheet | 65–80% | 85–95% | High-power LED panels, UGR<19 |
| 3.0–5.0 mm sheet | 55–70% | 90–97% | Industrial luminaires, outdoor |
Haze and transmission are matched to your LED layout — we tune the diffuser recipe so you get uniform light with minimum loss. Samples A4 are sent within 48 hours.
OEM/ODM Diffuser Manufacturing
Bakway manufactures diffuser plates on dedicated extrusion lines with in-house texture roller options: prismatic, micro-lens, matte and opal. We supply LED panel makers and luminaire brands worldwide with cut-to-size parts, edge finishing and light-meter test reports per batch. Custom light transmission targets (e.g. 70% ± 2%) are held on production with inline haze measurement.
What is the best light transmission for a PC LED diffuser?
For panel lights, 70–85% transmission with 85–95% haze is the standard balance between brightness and uniformity. Higher transmission (85–92%) suits strip covers; lower (55–70%) suits anti-glare industrial luminaires.
Can you make custom-size LED diffuser plates?
Yes — cut to size from 100×100 mm samples up to 2100×12000 mm sheets, with CNC edge finishing, protective film and batch light-meter reports.
What is the difference between diffuser sheet and frosted acrylic?
PC diffuser sheet combines impact resistance with precisely tuned haze, while frosted acrylic is brittle and hazes unpredictably. PC also withstands LED operating temperatures better.