does anyone on this forum use LED desk lamp? I am contemplating replacing my halogen desklamp with LED lamp. Halogen lamps produce a yellowish tint which I find discomforting.

I need your feed back on LED lamps. I hope to get a LED bulb that replace my 30watt halogen bulb.

I still find most LED's give too much of a blueish tint to make them useful for something like a desk lamp.

I wonder if using a "natural light" filter would do the trick?

Most probably it won´t. LEDs produce monochromatic light. Filtering can be used to remove undesired wavelengths or change the intensity of different wavelengths.

Of course one can make an array of LEDs. For example put some white, red, yellow, green etc, together. Then one would need to have a spectrometer and adjust the wavelength by manipulating amount of various LEDs in the array to match sun's frequency.
Could be a fun project for a science class <img src="/images/graemlins/smile.gif" alt="" />

There are blue coated halogen bulbs on the market. Your eyes see them as daylight. Usually sold in craft shop's and haberdasher's. Mostly to people who need to do accurate colour matching.

Actually it would be red, green and blue. They call it additive color mixing. With PWM you could adjust the brightness of the indivual colors and mix any color you want. And yes this could be a fun project for a science class.
BTW: Sunlight doesn´t have a single frequency. It has a wide spectrum. That is why it is so hard to imitate.

No, it's blue. It's a colour temperature shift. In exactly the same way you use a Blue Wrattan Filter for night phtography in order to prevent colour shift to orange. Additve is used to generate white light from L.E.D's.

there are high power LED lamps on the market but they are too expensive.

natural light lamp use Flourescent bulb. would Fluorescent bulb cause eye fatigue?