1. Should PIR lens surfaces be matte or glossy?
The surface finish affects not only the look but also how well the lens works. Glossy surfaces transmit more infrared light, giving the sensor a stronger signal. Matte finishes cut down glare and blend better with product design, which is why many consumer devices use them. In practice, engineers usually polish the actual lens area to be glossy while leaving the non-lens areas either matte or glossy, depending on design goals.
2. How are the lens and housing joined?
For high-volume production, double-sided adhesive tape is the simplest and cheapest option. It holds the lens firmly enough for indoor products. But outdoor cameras face rain and humidity, so additional sealing is common. Depending on the design, engineers add O-rings, cut grooves in the housing, or use waterproof tape and silicone gaskets. In factories overseas, especially in Vietnam, suppliers sometimes deliver lenses with waterproof tape already applied, so assembly workers only need to press the lens in place.
3. What is the impact of adding ribs in mold design?
Ribs around the lens edge make the structure stronger and improve how well the parts stay bonded. The trade-off is that the mold becomes more complex and expensive. Without ribs, the mold is simpler, but the finished product might be weaker or harder to seal against water. Adding ribs also often requires small hook holes, which further raises mold cost. So the decision usually comes down to the waterproof rating required and the target price of the product.
4. How are IP ratings reflected in the design?
If the device is for indoor use, engineers often choose the cheapest option: tape bonding only. Outdoor devices like CCTV units need at least a basic IP rating for dust and water. That means design choices such as grooves, silicone seals, or O-rings must be considered right from the mold design stage. Skipping this step early almost always causes redesign later.
5. What tools are used for PIR lens design?
Designers start with CAD software such as SolidWorks for the mechanical layout. At Fresnel Factory, engineers also run their own calculation tools to predict how the lens will shape the infrared field. After that, ray-tracing simulations check the detection zones, the field of view, and energy distribution. Using both mechanical and optical tools helps catch mistakes early, which saves time and money once molds are made.
6. What standards apply to PIR-based motion detectors?
Most companies follow IEC 63180. It defines three key tests: Radial (movement toward the sensor), Boundary (maximum distance and angle), and Tangential (side-to-side motion). These tests are easier to repeat with automated machines than with people walking back and forth. At Fresnel Factory, the Scaled Performance Machine was built to meet IEC 63180, so results are consistent across projects.
7. How much does performance testing cost?
A full set of the three IEC tests costs around USD 2,000. That covers radial, boundary, and tangential measurements. If a customer asks for extra scenarios—for example, testing the sensor at a higher mounting height—those are priced separately.
8. How long does it take to get a test report?
From the time Fresnel Factory receives the sample, testing and reporting usually take about three weeks. That includes running the measurements, reviewing the data, and preparing the report. For urgent projects, the three-week timeline can feel long, so it’s wise to build that time into the project schedule from the beginning.
9. How is the contract typically structured?
Most development contracts require a 50% down payment to begin work. The remaining 50% is due once the customer validates the sample. Mold costs are bundled into the development fee. Although the customer holds the rights to the mold, Fresnel Factory stores and maintains the physical mold and uses it for production. This arrangement is standard in the industry, since it protects quality and avoids problems with mold transfers.
10. Why are 3D modeling files required?
Without a 3D file, designers cannot check how the lens and housing fit together. Customers usually send STEP or IGES files, which show the exterior geometry. From that, engineers create lens patterns, plan mold details, and design seals for waterproofing. Even a basic exterior file is enough to start. Later, once molds are made, prototypes confirm that the design matches expectations. Sharing these files early helps prevent design errors and saves weeks of rework.
11. What materials are used for PIR lenses?
Most PIR lenses are made from Poly FIR200 or its compounded forms like SBK150 and HGW335. Poly FIR200 has good infrared transmission at 8–14 µm and flows well in injection molding. SBK150 is formulated for outdoor use and maintains performance even after years of UV exposure. Accelerated weathering tests show SBK150 still transmits more than 93% of its original level after five years, while cheaper alternatives may drop below 50%.
12. How are lens zones designed?
PIR lenses split the detection area into zones. For example, one design might use three zones covering 35°, 15°, and 7°. This allows the sensor to detect people moving at different heights and angles. If the zones are poorly planned, blind spots appear where motion is missed. That’s why zone design is usually checked both in simulation and in field tests before finalizing.
13. What is the service life of a lens mold?
A well-maintained PIR lens mold can last around four years and produce roughly 150,000 units per year. Actual lifetime depends on the plastic used, production conditions, and how often the mold is polished. Because the lens surface has fine patterns, wear shows up as lower optical performance, not just cosmetic flaws. Regular inspection and light re-polishing extend mold life.
14. How are final product shipment tests carried out?
Before shipment, customers may request a full IEC test or rely on the factory’s own quality checks. Final inspections usually measure detection distance, angle coverage, noise resistance, and waterproofing. In large production runs, even a 0.5% increase in defect rate can mean serious financial loss. For that reason, suppliers and customers should agree on the test scope and acceptance criteria early, before the first shipment leaves the factory.
