Author: Myung Joong Kim, CEO, Fresnel Factory
Quick Answer
PF25-09015A is an off-the-shelf PIR Fresnel lens designed for wall-mounted burglar alarm detectors,
PIR camera modules, and indoor surveillance motion sensors. It is specified for a 100° detectable angle,
12 m detectable distance, and 25 mm sensor-to-lens distance.
- Designed for wall-mounted, pet-immune PIR detector applications.
- Uses a multi-zone field-of-view structure shown as detection regions A through P.
- Can support cross-zone confirmation and movement-pattern filtering in PIR detector logic.
- Helps create broad room coverage compared with a narrow curtain-style detection approach.
- Suitable for burglar alarm sensors, security cameras, and indoor surveillance motion detectors.
Why is PF25-09015A suitable for wall-mounted burglar alarm sensors?
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A burglar alarm motion detector must identify meaningful human movement while avoiding unnecessary alarms
caused by pets, airflow, temperature changes, sunlight, electrical noise, or short environmental disturbances.
The PIR sensor, signal-processing circuit, installation condition, and Fresnel lens must work together as one system.
PF25-09015A is designed for wall-mounted PIR detector configurations. Its datasheet specifies a
100° detectable angle, 12 m detectable distance, and
wall-mounted, pet-immune installation. These characteristics make it a practical starting point
for indoor burglar alarms, PIR photo cameras, and room-monitoring surveillance devices.
The lens has an overall size of 57.7 × 36 mm and a nominal
sensor-to-lens distance of 25 mm. This gives enclosure and PCB designers a defined optical
reference when developing a detector housing.
How does the multi-zone field-of-view structure help reduce blind areas?
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Many conventional wall-mounted PIR detectors use a limited number of broad zones or narrow curtain-style
detection patterns. Curtain-type optics can be useful for corridors, doorways, or perimeter-crossing detection,
but they may leave coverage transitions when the objective is broad room monitoring.
The PF25-09015A field-of-view drawing shows multiple optical detection regions identified from
A through P. Rather than relying on a single narrow sensing curtain, the lens distributes
detection coverage across a wider monitored area.
This multi-zone optical structure can help a detector designer create a more continuous room-monitoring pattern.
In a properly designed system, it can reduce large coverage transitions that may occur with simplified curtain
layouts and provide more information about how a moving target crosses the field of view.
Actual blind-area performance must be verified with the final mounting height, detector tilt angle, PIR sensor
alignment, room geometry, furniture layout, and enclosure design.
How can multiple PIR detection zones support lower false-alarm risk?
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A Fresnel lens alone does not guarantee false-alarm reduction. False-alarm performance depends on the complete
detector system, including the PIR sensor, analog front end, firmware, threshold settings, installation condition,
and environmental test results.
However, a multi-zone lens structure gives the product designer more options for configuring motion-event logic.
When a target moves through several optical zones, the PIR detector can evaluate the sequence, duration, and
consistency of the signal rather than reacting to one short disturbance.
| Detector Logic Concept | How a Multi-Zone Pattern Can Help |
|---|---|
| Cross-zone confirmation | Require movement across more than one detection region before making an alarm decision. |
| Directional movement analysis | Evaluate the signal sequence as a target moves from one zone to an adjacent zone. |
| Time-based filtering | Reject very short or isolated disturbances that do not continue through the expected field of view. |
| Signal consistency check | Compare expected signal behavior across multiple optical regions. |
| Pet-filtering strategy | Combine the pet-immune lens configuration with thresholds, timing rules, and movement-pattern filtering. |
This approach is especially relevant for burglar alarm and surveillance systems where the detector must respond
to meaningful intrusion events while minimizing nuisance triggers.
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What are the key specifications of PF25-09015A?
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| Specification | PF25-09015A |
|---|---|
| Product Type | PIR Fresnel Lens |
| Installation | Wall-mounted, Pet Immune |
| Detectable Angle | 100° |
| Detectable Distance | 12 m |
| Sensor-to-Lens Distance | 25 mm |
| Overall Size | 57.7 × 36 mm |
| Material | Poly FIR200 |
| General Tolerance | ±0.2 mm |
How does PF25-09015A compare with a basic curtain-type PIR lens?
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| Design Consideration | PF25-09015A | Basic Curtain-Type Lens |
|---|---|---|
| Primary Application | Broad wall-mounted room monitoring | Corridor, doorway, or perimeter crossing |
| Detection Pattern | Multiple field-of-view regions shown from A to P | Often focused on narrow crossing zones |
| Coverage Approach | Distributed coverage for general room monitoring | Focused coverage along a selected path |
| Motion Analysis | Supports cross-zone and directional logic concepts | Provides fewer optical regions for movement sequence analysis |
| Pet-Immune Configuration | Specified as pet immune in the datasheet | Depends on the specific lens and detector design |
A curtain lens remains a suitable solution for narrow-path applications. PF25-09015A is more appropriate when
the goal is broad wall-mounted coverage for a room, burglar alarm detector, or surveillance motion sensor.
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What should be validated before releasing a PIR detector to production?
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- Sensor alignment: Maintain the intended 25 mm sensor-to-lens distance and optical-axis alignment.
- Installation height and tilt angle: Confirm coverage using the actual wall-mounted installation position.
- Pet-immunity testing: Test with the intended pet size, movement speed, detector height, and alarm settings.
- Human detection testing: Verify the required coverage and detection behavior across the final room layout.
- Nuisance-alarm testing: Evaluate HVAC airflow, sunlight, thermal reflections, insects, electrical noise, and rapid temperature changes.
- Final enclosure validation: Confirm that the housing aperture, decorative cover, adhesive, gasket, and mechanical tolerances do not influence the optical pattern.
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Why use an off-the-shelf PIR Fresnel lens before developing a custom lens?
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PF25-09015A can be used as an initial optical platform before committing to a custom Fresnel lens project.
An off-the-shelf lens helps engineering teams evaluate PIR sensor selection, optical depth, field-of-view coverage,
pet-filtering algorithms, and detector electronics before finalizing the mechanical enclosure.
A custom Fresnel lens may be required when the product needs a different mounting height, enclosure shape,
sensor arrangement, field-of-view pattern, detection distance, or installation angle.
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Frequently Asked Questions
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Is PF25-09015A designed for wall-mounted PIR detectors?
Yes. The PF25-09015A datasheet specifies wall-mounted installation.
What is the detectable angle of PF25-09015A?
The datasheet specifies a detectable angle of 100°.
What is the detectable distance of PF25-09015A?
The datasheet specifies a detectable distance of 12 m.
Is PF25-09015A a pet-immune PIR lens?
The datasheet identifies PF25-09015A as a wall-mounted, pet-immune lens. Final pet-immunity performance
must be validated with the complete detector system.
Can PF25-09015A independently eliminate false alarms?
No. False-alarm performance depends on the PIR sensor, electronics, signal-processing algorithm,
mounting condition, and environmental test results. The multi-zone pattern can support filtering logic
such as cross-zone confirmation.
Does PF25-09015A remove every blind spot?
No PIR lens removes every blind spot in all installations. Its multi-zone field-of-view pattern can help reduce
coverage transitions compared with a simplified curtain-type layout when used for broad room monitoring.
What is the required sensor-to-lens distance?
The datasheet specifies a 25 mm sensor-to-lens distance.
What are the overall dimensions of PF25-09015A?
The overall size is 57.7 × 36 mm with a general tolerance of ±0.2 mm.
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Evaluate PF25-09015A for Your PIR Security Sensor
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PF25-09015A is suitable for engineers developing wall-mounted burglar alarm sensors, PIR cameras,
and indoor surveillance motion detectors that require broad coverage, pet-immune configuration,
and multi-zone motion analysis.
Request PF25-09015A evaluation samples
Request a technical review or custom PIR lens consultation
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