High power ultraviolet LED experiments

Summary

The script describes experiments conducted with a high-power 395nm purple LED purchased for UV curing applications. Various capacitors are placed in series with the LED to observe the effect on light output and power. Initial power is 45W. A 100nF capacitor drops this to 0.6W with visibly dim output. Larger capacitors proportionally increase brightness and power, up to 5.9W with 1μF. Motor run capacitors of 2mF and 4mF further limit power to 11.5W and 23W respectively while maintaining useful brightness, potentially increasing LED life by reducing heat.

Takeaways

• 😀 The video covers experiments on controlling the brightness of a 395nm purple LED using capacitors
• 😎 The goal is to reduce LED power to extend its life while still emitting useful UV light
• 💡 The stock LED draws 45W at full power
• 🔋 Adding a 100nF capacitor drops power to 0.6W
• 🔋 A 220nF capacitor allows 1.3W, and 330nF allows 1.9W
• 🔋 Larger capacitors continue to increase power, with 1μF yielding 5.9W
• 🤔 Motor run capacitors allow even more control of LED power and light output
• ⚡ A 2mF motor capacitor runs the LED at 11.5W
• ⚡ A 4mF capacitor runs it at 24W, halving the stock power
• 💡 The experiments show capacitors can easily control LED power and life versus output

Q & A

What type of LED is being experimented with?

A 395nm wavelength (deep violet) high power 50 watt UV LED module intended for 3D printer resin curing.

How is the LED module powered and current regulated?

It uses a mosfet and l1015 chip to regulate drive current instead of multiple linear current regulator chips.

Why use flip chip LEDs in the module?

Flip chip LEDs connect directly to pads on the surface so don't need wire bonds, allowing for compact size.

What capacitance values were tested in series?

100nF, 220nF, 330nF, 470nF, 1μF, 2μF and 4μF motor run capacitors.

How did adding capacitors in series impact brightness and power?

Increasing capacitance increased brightness and power up to about half rating, extending LED life by reducing drive level.

What was the no-load power draw of the LED module?

45 watts initially with no series capacitors.

What safety precautions were taken?

Wearing insulating gloves when handling powered connections.

How can the capacitors be safely discharged after testing?

By shorting leads with insulated handles and checking voltage decays to safe level.

What benefits did the testing show?

That LED brightness and power can be easily adjusted for specific applications by adding series capacitors.

What ideas did the experiments give for future work?

Building the LED and capacitors into a case to make a adjustable output UV curing light.