3W SMD High Power UV LED Bead - 395nm to 400nm Purple Ultraviolet UVA Emitter

Specifications:

• Wavelength: 395nm - 400nm (UVA / Blacklight Spectrum)
• Power Dissipation: 3 Watts
• Forward Voltage (VF): 3.4V – 3.8V DC
• Forward Current (IF): 700mA (Constant Current Mandatory)
• Radiant Intensity: 500mW – 650mW
• Viewing Angle: 120° – 140° (Wide Flood Pattern)
• Operating Temperature: -30°C to +85°C (Requires active cooling)

Key Applications & Projects

• Blacklight Effects: High-intensity illumination for UV-reactive paints, posters, and glow-in-the-dark events.
• Currency & Document Verification: Instantly reveals security threads and watermarks on banknotes, passports, and IDs.
  UV Curing: Rapidly cures UV-sensitive glues and resins used in smartphone repairs and DIY crafts.
• Leak Detection: Detects fluorescent dyes in HVAC and automotive systems to find micro-leaks.
• Forensic Fun: Identifying organic traces or "invisible ink" messages for escape rooms and educational kits.

Project Evolution 

• Past Projects (Prerequisites): If you've used standard 5mm UV LEDs and found them too dim for large areas, this 3W bead is the next logical step.
• Feature Upgrade: Transitioning to this high-power emitter allows for Project Scaling. One 3W LED provides the equivalent radiant output of nearly 50 standard 5mm LEDs, simplifying your wiring and power management.
• Effort/Requirements: Intermediate. Requires a 700mA constant current driver and a 20mm aluminum star PCB for heat dissipation.

Virtual Technician & Wiring

• ⚠️ SAFETY WARNING: Never stare directly into the LED while powered. Even though 395nm is visible, the high-intensity UV radiation can cause eye fatigue and damage.

• Thermal Management: Do NOT operate this LED for more than 3 seconds without a proper heat sink. It will overheat and fail permanently.

Wiring Guide:

• Anode (+): Connect to the positive output of a 700mA Constant Current Driver.
• Cathode (-): Connect to the negative output.
• Power Supply: If using a 12V DC source, pair with a buck-converter LED driver for maximum efficiency.

​Packages include:

1 X3W SMD High Power UV LED Bead - 395nm to 400nm Purple Ultraviolet UVA Emitter

Frequently Asked Questions (FAQ)

1. Why does 395nm look more "purple" than 365nm?
   395nm is closer to the visible light spectrum (400nm+), resulting in a visible violet glow.
2. Can I use a 9V battery with a resistor?
   Yes, but a 3W LED draws 700mA, which will drain a standard 9V battery in minutes. Use a Li-ion pack with a driver instead.
3. Is this LED suitable for plant growth?
   While plants use some UVA, this is primarily for fluorescence and curing. Look for Full Spectrum LEDs for gardening.
4. How do I solder this to a PCB?
   Use a hot plate or a reflow station for best results, as the thermal pad underneath the LED must be bonded to the PCB.
5. Will this cure 3D printer resin?
   Most 405nm resins will cure under 395nm light, but it may take slightly longer than a dedicated 405nm source.
6. Can I use this for a pet urine detector?
   Absolutely. 395nm is perfect for making organic stains fluoresce in the dark.
7. Does it come with a lens?
   This is a raw SMD bead. You can add an external 20mm LED lens to narrow the beam from 120° to 15° or 30°.
8. What is the difference between this and a "Blacklight" tube?
   This LED is much more energy-efficient, compact, and offers a more concentrated point source of UV.
9. Can I run this at 350mA?
   Yes. It will be less bright but will run much cooler and last longer.
10. Is the wavelength exactly 395nm?
    It covers the band from 395nm to 400nm.
11. Does it work for curing UV glue on phone screens?
    Yes, it is a standard tool for LOCA (Liquid Optical Clear Adhesive) curing.
12. Is it dimmable?
    Yes, but only via a PWM-capable LED driver.
13. Will it fade my clothes?
    Prolonged exposure to any UV light will eventually cause "photodegradation" or fading of fabrics.
14. Is this LED waterproof?
    No, the bead must be protected by an enclosure for outdoor use.
15. Why do I need a constant current driver?
    LEDs are current-driven devices. A small voltage spike can cause a large current jump, burning out the LED without a driver.
16. How much heat does it produce?
    Significant. The back of the LED can reach 80°C+ within seconds without a heat sink.
17. Can I use this for photography?
    Yes, for "Blacklight Photography" to capture fluorescent colors.
18. Is it safe to use at home?
    Yes, provided you don't look directly at it and use proper heat sinks.
19. What is the lifespan?
    Rated for 50,000 hours if junction temperatures are kept below 85°C.
20. Is this UVA, UVB, or UVC?
    This is UVA, the safest and most common UV band for consumer use.