UK Client Custom Sunroof Panel Light: CRI97, UGR19, Tunable White – The Journey from Sample to Mass Production

1. Client Requirement: Not Just a "Light," But a "Sunroof Effect"

In May of this year, we received a custom inquiry from a UK-based client.

This British company was seeking a lighting solution for a high-end commercial project — they didn't want just ordinary panel lights. They wanted a lighting system that could simulate a sunroof effect.

Core Requirements:

• Size: 600×1200mm (standard commercial panel size, suitable for recessed installation)

• Anti-glare: UGR19, ensuring no visual disruption in office environments

• High color rendering: CRI97, color accuracy close to natural light

• Tunable White: 2700-6500K, full range from warm to cool light

• Smart control: DALI dimming + power supply, integrated into the intelligent lighting system

• Mounting: Recessed, flush with the ceiling

Why such high specifications?

Because this project was a lighting upgrade for a premium commercial space — the user wanted more than just "brightness." They wanted to create the feeling of natural daylight streaming through a skylight. CRI97 ensures authentic color rendition throughout the space. UGR19 ensures comfortable, non-intrusive lighting for long office hours. Tunable White enables the transition from morning to evening light tones.

This was a project about "light quality," not just "light output."

2. Sample Stage: Technical Validation and Communication

Upon receiving the requirements, our engineering team immediately began sample development.

Technical Challenges:

1. CRI97 + UGR19 combination: High color rendering and low glare present a technical trade-off in optical design. Finding the optimal balance between diffuser and lens solutions was critical.

2. Tunable White 2700-6500K: Requires precise color mixing of two CCT LED channels to ensure consistent color coordinates and no color deviation across the entire color temperature range.

3. DALI dimming: Needed seamless integration with the client's intelligent lighting system.

After sample completion, we shipped them to the UK client for testing.

Side Note: DALI Dimming vs. Flicker

After receiving the samples, the client reported an issue: "It seems there is flicker when dimming?"

Our technical support team responded immediately. After communication, we discovered that the client had misinterpreted DALI dimming's stepwise transitions as flicker.

DALI dimming operates via digital signal control — brightness adjusts in discrete steps (similar to digital volume control), rather than the continuous smooth transition of analog dimming. This "stepped" sensation can sometimes be mistaken for flicker in certain use cases.

We explained to the client:

• DALI dimming's stepped transitions are a normal operating characteristic, not flicker

• True flicker refers to rapid fluctuations in light output over time, typically caused by poor-quality drivers

• We use high-quality DALI drivers with no flicker risk

• Dimming curve parameters can be adjusted to optimize the smoothness of the step transitions

Once the client understood, they confirmed the samples were satisfactory and officially placed the mass production order.

3. Mass Production: Quality Control and Delivery Management

After the mass production order was confirmed, our production team immediately initiated scheduling.

Key Process Steps:

1. Optical material procurement: CRI97 requires high-quality LED chips and phosphor formulations. UGR19 requires custom anti-glare diffusers and louver solutions. We sourced some optical materials from Germany to ensure optical performance met specifications.

2. DALI driver matching: DALI dimming imposes stringent requirements on drivers. We ensured complete electrical compatibility between drivers and fixtures, as well as full compatibility with the client's DALI system.

3. CCT consistency control: The greatest risk for Tunable White products is CCT variation between individual fixtures. We used high-precision spectrometers to sort LEDs by CCT for each batch, ensuring color tolerance within 3SDCM.

4. Burn-in testing: All fixtures underwent 72-hour burn-in testing before shipment to ensure stability and reliability.

4. Client Factory Inspection: A Journey of Trust from the UK to China

Because this project was critically important to the client, they decided to personally visit China in July for a factory inspection.

This was both a challenge and an opportunity for us.

              
Inspection Process:

1. Visual inspection: The client examined surface finish, frame flatness, and diffuser quality on each fixture

2. Dimensional verification: Confirmed precise 600×1200mm dimensions and correct recessed mounting clip positions

3. Optical testing: Using our lab's integrating sphere spectrometer to measure CRI, CCT, luminous flux, and other parameters

4. UGR testing: Anti-glare performance testing in a dark room to confirm UGR≤19

5. DALI dimming test: Connected to the client's DALI system to test dimming linearity, smoothness, and response speed

6. Tunable White test: Full-range testing from 2700K to 6500K to verify uniformity and consistency of CCT transitions

Inspection Results: All passed.

During the inspection, the client was impressed by our production facility, quality control processes, and laboratory equipment.

Client Feedback:

"I'm impressed by Lumin's quality control system. The samples we tested all met our specifications. This gives us confidence for the project."

5. Final Delivery: A Satisfied Client, A Successful Partnership

After inspection, we proceeded with packaging and shipment according to the client's requirements.

Packaging Solution:

• Each fixture individually packed with foam protection to prevent damage during transit

• Reinforced outer cartons with "Fragile" and "This Way Up" markings

• Test reports (including CRI, CCT, UGR data) included with each shipment

The goods arrived safely in the UK. After installation, the client sent us on-site photos and feedback:

"The lights are perfect. The sunroof effect is exactly what we wanted. And the CRI97 makes the space look so natural. Thank you Lumin!"

6. Why Did the Client Choose Lumin?

This case demonstrates Lumin's core capabilities in OEM customization:

1. Precision in Meeting Complex Technical Specifications
CRI97 + UGR19 + Tunable White + DALI dimming — each parameter alone is challenging; combining them is even more demanding. Our engineering team can fully address client requirements across optical, electrical, and mechanical dimensions.

2. Professional Technical Communication and Support
When the client misinterpreted DALI dimming characteristics as flicker, we were able to provide timely, professional explanations to resolve concerns. This "technical trust" is the foundation of long-term partnerships.

3. Rigorous Quality Control
From material procurement to assembly, from burn-in testing to final inspection, every fixture undergoes stringent testing. The client's factory inspection with "100% pass" results speaks for itself.

4. Transparent Partnership Process
From sample to mass production, from online communication to on-site inspection, we ensured the client could see, touch, and trust every step of the process.

7. Conclusion

This case reminds us that OEM customization is not just "manufacturing to print" — it is a complete journey of understanding requirements, solving technical challenges, and building trust.

From the initial sample inquiry in May to the client's factory inspection in July to final delivery — every step solidified the client's trust in Lumin.

Whether you need high-CRI, low-glare panel lights or intelligent lighting systems featuring Tunable White and DALI dimming, Lumin offers professional OEM customization services.

Want to learn more about Lumin's panel light OEM customization? Download the Lumin product catalog or contact our OEM business team.

         
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