1. What Is a Photosensitive Receiver Tube?
The photosensitive receiver tube is the “eye” of the infrared pair — it detects the invisible light emitted by an IR LED and converts it into an electrical signal. There are two main types:
- Photodiode: ultra-fast response (nanosecond level) with excellent linearity, ideal for high-speed signal transmission and precision measurement
- Phototransistor: built-in amplification with higher sensitivity and larger output current, ideal for switching/detection applications
Common center wavelengths are 850nm / 875نانومتر / 940nm — the same as IR emitters, and they must be matched one-to-one with the emitting side.
> 💡 BOOYII Advantage: Photosensitive receiver tubes are one of Ningbo BOOYII Electronics’ two flagship product lines, backed by a 20-year stable supply history. We offer pair-tube solutions with wavelength-matched and sensitivity-matched IR emitters from our own production — factory-matched and ready to use.
2. Top 10 Application Fields of Photosensitive Receiver Tubes
1. Home Appliance Remote Receivers (The Classic Application)
After the remote control sends an infrared command, a 940nm receiver tube (combined with a decoder IC, forming a remote receiver module) completes the reception. Every TV, air conditioner, and set-top box contains one — making it the highest-volume infrared application worldwide.
2. Security Surveillance & Night-Vision Systems
At night, the camera emits 850nm IR illumination, and the reflected light completes the imaging chain through high-sensitivity photodiodes working with the image sensor. Other security uses:
- Infrared beam-break detectors (perimeter protection)
- Active infrared intrusion detection (walls, doors, windows)
- Laser beam alarm systems
3. Industrial Automation: The Receiving End of Photoelectric Switches
Paired with IR emitters to form through-beam / retro-reflective photoelectric switches, the receiver tube determines whether the light path is blocked:
- Production-line counting and missing-part detection
- Liquid-level and material-level detection
- Transparent film and glass-edge detection
- Safety-door anti-pinch and safety light curtain receivers
4. The Receiving Side of Optocouplers (Photocouplers)
An optocoupler = an IR emitter + a photosensitive receiver (usually a phototransistor) sealed in one package. The receiver converts the optical signal back into an electrical one, achieving complete electrical isolation between input and output — indispensable in switching power supplies, inverters, PLCs, and communication modules.
5. Smart Home & Human Presence Sensing
- Smart toilets: receiver tubes detect human proximity signals
- Sensor faucets / soap dispensers: receivers detect reflected IR to trigger water flow
- Robot vacuums: receiving ends of cliff detection, wall-following, and anti-collision sensors
- Air-conditioner louver position detection and optical path detection
6. Medical & Health Monitoring
- Fingertip pulse oximeters: photodiodes receive the 660nm red light and 940nm infrared light transmitted through the fingertip to calculate SpO2
- Heart-rate wristbands/watches: receivers detect light-intensity changes caused by blood pulsation (PPG — photoplethysmography)
- Optical receiving channels in biochemical and urine analyzers
- Supporting signal chains for ear-thermometer thermopiles
Medical applications impose extremely strict requirements on dark current, signal-to-noise ratio, and batch consistency — among the most technically demanding fields for receiver tubes.
7. Consumer Electronics
- TWS earbud in-ear detection (through-beam or reflective emitter+receiver sets)
- Smartphone proximity sensors (auto screen off during calls)
- IR remote receiving (set-top boxes, TV sticks)
- Optical interaction in gaming devices and toys
8. Automotive Electronics
- Ambient light / sunlight detection for automatic headlights (photodiodes)
- IR receiving chain in in-cabin driver monitoring systems (DMS)
- Rain sensing (receiver end of reflective infrared rain sensors)
- Key-fob proximity detection and welcome-light triggering
9. Ranging & Signal Acquisition
- Triangulation ranging sensors: PSD/photodiodes receive the position of reflected light spots
- Paper detection and double-sheet detection in printers and copiers
- Pulse reception in encoders and linear scales (high-speed photodiodes)
- Optical signal reception in fiber communication (PIN photodiodes, avalanche photodiodes / APDs)
10. Ambient Light & Lighting Control
- Photocell street lights and night lights: phototransistors sense ambient light intensity for automatic switching
- Auto-brightness adjustment for monitors and phones
- Light-intensity monitoring in agricultural greenhouses
- Auxiliary reception in photoelectric smoke and flame detectors
3. How to Select a Receiver Tube: A Quick Guide
| Key Parameter | Typical Value / Description | Selection Advice |
| Peak Response Wavelength | 850نانومتر / 875نانومتر / 940نانومتر | Must match the emitter’s wavelength |
| Photocurrent | 0.1–10mA class (@1mW/cm²) | Determines sensitivity and signal margin |
| Dark Current | Lower is better (nA class) | Critical for medical and precision measurement |
| Response Speed | Photodiode: ns level / Phototransistor: μs level | Choose photodiodes for high-speed transmission |
| Collector-Emitter Voltage VCEO | 20–40V | Match with the circuit supply |
| Package Type | Through-hole 3mm/5mm, SMD, with light-shield cap, side-receiving type | Remote receivers often use side-view packages with light-shield caps against ambient light |
> ⚠️ Important: Receiver tubes also respond to ambient light (sunlight, incandescent lamps). Selection must address light-shield structure design + filter wavelength matching + software filtering — a triple defense. Otherwise, you may face hidden issues such as daytime false triggering or drifting sensing distance at night. Choosing factory-matched emitter+receiver pairs systematically eliminates this risk.
4. Why Do Customers Worldwide Choose BOOYII Receiver Tubes?
- ✅ 20 Years of Focus: Dual flagship lines — receiver tubes and IR LEDs — with a stable customer base of 20 years
- ✅ Matched Pair Supply: Emitter + receiver wavelength/sensitivity matched before shipping, zero hassle in system debugging
- ✅ Certified Quality Systems: certified; CE and RoHS certifications
- ✅ Full Series Coverage: Photodiodes and phototransistors in through-hole, SMD, and side-receiving packages
- ✅ Flexible Service: OEM/ODM supported, with selection advice and fast sampling
5. Conclusion
If the IR emitter is the “voice,” the photosensitive receiver tube is the “ear.” No matter how strong the signal, without a highly sensitive and consistent receiving end, reliable product performance is impossible. With 20 years of pair-tube matching experience, BOOYII delivers the complete optical signal chain — from emission to reception.
For receiver tube / IR pair samples and technical support, contact us:
🌐 www.booyii-led.com | Ningbo BOOYII Electronics, الصين
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