What can measure the spectrum frequencies of a monitor?

Question

I often have adverse health effects when sitting behind a monitor for more than a short period of time. I am interested in finding out, what exactly it is that's affecting me. For example, I have certain monitors behind which adverse health effects start after 15 minutes -- even if it's couple feet away; others take a couple hours to kick in. By measuring different aspects of these monitors, I was hoping to be able to zero in on, what exactly it causing these effects.

The first thing I was planning to do was, to measure the frequency of the screen flicker by hooking up a photodiode to an oscilloscope. However, I do not expect the results to be very different from, say, a regular LED lamp. On the other hand, LED lamps do not affect my health adversely -- so, it is probably only certain wavelengths which affect me adversely.

So the other thing that I would need is, a spectrometer to measure the light from the monitor, to see which frequencies occur how often. Preferably, it should be something that can be adapted to tell me the frequency also -- but even a regular spectrometer I'll take. The only types of spectrometers I've been able to find either measure the spectrum of liquids, gases, or give only the single highest frequency. I am not familiar enough with spectroscopes to know, whether any of these types can be adapted to measure visible light.

No budget limit right now, just a matter of seeing whether it's possible.

Answer 1

For monitors, you don't need to do this at all. It's in the monitor spec. Have you ever seen a monitor boast it has a 120hz Refresh Rate? In perhaps the simplest equivalency in computing, 1 Hertz = 1 Frame each second.

Frames are the still images displayed by the screen. Just like movies, we still view our screens as a series of rapidly changing still images. This is why when you experience "graphics lag", you get visual stuttering, as the computer hangs on a frame and fails to send updates to the monitor. Low refresh rates, common in older, CRT monitors and early LCDs, can cause headaches and eye discomfort. High refresh rates allow for improved clarity, a more comfortable viewing experience, and more fluid motion.

Makers are required by law in many places to display this information on the packaging, due to the very health concerns you're experiencing. They're more than happy to provide the information, as it's an accurate measure of image quality and they're eager to show off high rates that allow for 3D Stereoscopic viewing; however, if the monitor has aged, this can degrade the monitor quality with use. It shouldn't be noticeable, but if you're like me and hang on to monitors until they go black and never turn on again, it might be something that has happened. For situations like that, you can use the computer itself to test the monitor (as it must internally just to sync its images) using tools provided by your graphic card manufacturer or websites like this one. You can just look up the monitor model online for the base spec, and you can view the monitor properties in Device Manager or Display Properties on a Windows system to see its operational Refresh Rate.

By all means, give this a try and post your rates, it might be a good supplement to the question to know your results!