Computer monitors with extremely low electromagnetic emissions
Here are shown the results of our research for a computer monitor with no harmful electromagnetic emissions. This research started many years ago when the common computer monitors were still CRT (Cathode Ray Tube). Then around year 2000 we started using LCD monitors but we found that they still had a lot of electromagnetic radiation, so we started to try some modifications of the commercial LCD monitors.
These monitors have the same picture quality of the best commercial monitors but internally they have been modified to avoid all the electromagnetic emissions that come from the backlight lamps and cables and the monitor's main electronic board.
A low emission monitor is aimed especially to sensitive users but everyone who uses a computer, for work or hobby, for more than one hour a day, would get great benefits from removing the electromagnetic emissions from the monitor. This monitor is recommended to CAD designers, designers, writers, programmers, software developers, video technicians, researchers and all people who need computer monitors without electromagnetic emissions. This monitor is a good solution also for those special applications that need a monitor with extremely low electromagnetic emissions, like in some scientific researches.
What is the difference in these monitors
The exterior of these monitors is more or less like any other commercial LCD monitor but internally they are very different from common monitors. The CCFL (Cold Cathode Fluorescent Lamp) back light of the LCD module has been replaced with a set of white LEDs designed for this purpose. The switching power supply and the inverter have been completely removed. The monitor's main electronic board has been detached from the monitor's container and put in a separate metal box with no apertures. The small electric power for the LED backlight, and the power for the LCD module and the controller board, are provided by separate circuits of a linear power supply with very low electromagnetic noise. Such modified monitors have also a much lower energy consumption, the power drawn from the mains is just about 10 W.
Tenth version
| The tenth version of our low EMF LCD monitor is a 24". We have been able to use the original plastic structure of the monitor. The power supply box is made of aluminum alloy with black cover. The backlight of the monitor is the original one, but it's powered by a DC voltage of 20-28 V. The driver board works at 19 V DC. The results in terms of EMF are still the same. |
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Ninth version
| The ninth version of our low EMF LCD monitor is a 24". We have been able to use the original plastic structure of the monitor. We also used a custom designed steel enclosure for the power supply. The backlight of the monitor is the original one, but it's powered by a DC voltage of 20-28 V. The results in terms of EMF are still the same. |
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Eighth version
| The eighth version of our low EMF LCD monitor has the same internal components of our previous version but it has a different external structure. We have been able to use the original plastic stricture of the monitor. We also used a custom designed steel enclosure for the power supply. The backlight of the monitor is the original one, but it's powered by a DC voltage of 40-50 V. The results in terms of EMF are still the same. |
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Seventh version
| The seventh version of our low EMF LCD monitor is profoundly different from the previous version. Now the LED strip of the LCD module has not been replaced, it is just powered by a DC voltage of 40-50 V. The power supply is more complex than before. The backlight connector is different, and more robust. The results in terms of EMF are still the same. |
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Sixth version
| The sixth version of our low EMF LCD monitor is just an improvement of the fifth version. The frame is still made of solid hardwood. The metal enclosure of the main board is partially inserted into the wooden panel and it is covered by other wood panels for a better protection. |
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Fifth version
| The fifth version of our low EMF LCD monitor is based on the same principles of the previous versions but it has a nice frame made of solid wood and the picture quality is practically unchanged respect to the original monitor. |
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Fourth version
| In the fourth version we have built an entirely wooden frame to hold the LCD panel and the metal box of the main board. This is more robust than cardboard and it also has a nice look. |
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Third version
| In the third version we abandoned the original monitor's structure and started to build a different structure to contain the LCD panel and the monitor's board. This structure is like a frame and it is made of wood and cardboard and possibly other materials. The metal box is placed on the back of the frame. |
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Second version
| The second version of our modified LCD monitor was still based on the original monitor's structure but the metal box of the monitor's electronic board was attached on the back of the monitor because the internal signal cable could not be replaced. The results however was still good enough because the metal box shielding was good. |
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First version
| Our first modified LCD monitors were made using the original monitor's structure. The metal box of the monitor's electronic board was placed away from the monitor by means of an extension of the internal signal cable. |
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Comparisons with other solutions
In the past years we have seen many proposals of gadgets that promised the cancellation of electromagnetic fields emitted from computer monitors: there was who was trying to sell you an amulet, "rare earth crystals", pendants,... of course that things have small or no effect.
Some small company provided LCD monitors modified internally with MuMetal sheet to shield the magnetic field, but without removing any of the sources of electromagnetic radiation.
Our solution is much better because we have removed most of the sources of electromagnetic emissions from the LCD monitor. In this modified monitor the circuits and cables that create the strong electromagnetic fields have been removed completely, and a special power supply with very low electromagnetic noise is used.
Several people from all over the world have tried to modify a desktop LCD monitor to reduce its electromagnetic emissions. Some people tried to shield the internal parts with one or more layers of metal foil, using also different metals with different electromagnetic properties.
In our opinion the shield with thin foil is far from being enough, because the emissions coming from the controller board are quite strong, and of various kind, and so a part of them passes through the thin shield. In addition the CCFL lamps are impossible to shield because they are directly attached to the light diffuser behind the TFT panel. Finally, even if the front of the monitor is closed with transparent conductive shield the shield is not completely closed around the monitor because that materials have a little shielding effectiveness.
Our solution is much better because we have removed the electronic circuits not just the internal power supply but also the inverter, the CCFLs tubes and wires. The controller board is enclosed in a robust box made of zinced iron, with no apertures except the two holes needed for the cables.
More information
If you want to receive more detailed information about these modified monitors with very low EMF emissions, contact us.
Related pages
Arrangement of this modified monitors
External power supply of this modified monitors
Gallery of modified LCD monitors with low EMF
LCD monitor emissions