Use RFB Framework to Choose a Good Monitor for Long Work

I  use computer primary for browsing, coding , and writing. A good monitor helps me to work more efficiently and keep my eyes comfortable. To get a good monitor for my needs, I design RFB framework stands for Resolution, Flicker, and Brightness to help.

Resolution – it’s Bi-direction

The monitor provides fixed pixels within fix dimension. Higher resolution means more detail on screen. But it’s not always higher is better, your feeling is important, too. It’s not comfortable to see small things for long time nor to click on them. There is a limit of your eye resolution.

You may change how it use each pixel to display information with different operating system.  Most may provides different resolution options on screen, and some may control how many pixels on icon which means you don’t need to sacrifice size to higher resolution.

Flicker – Read my Lips: NO!

With LED as the light source for LCD, to change the brightness means to different cycling the LED backlight. This technique is PWM. TFT Central has a great article explaining the whole story.

When the cycling is slow, you might notice flickering and feel uncomfortable after long working. Then you need a flicker free monitor. It may be achieved with much higher cycling frequency or  use DC (direct current) for backlight dimming to replace PWM.

Not every company put flickering information in spec. You may take a look at the two source to check if your monitor is flicker free.

  1. TFT Central: Flicker Free Monitor Database
  2. PC Monitors: Forum: Flicker-free monitors

Brightness – Enough is Enough

I have cataract and have one intraocular len in my right eye. Therefore, I preferred to work at lower brightness.

Most IPS and VA monitors are too bright for me. Therefore, I stay with TN.

ewaller posts an interesting reply on bbs of in topic How to adjust brightness/contrast with xorg/intel? I like how he explains brightness, contrast, color, and backlight. It helps me to understand them from a broadcast view.

“Brightness” controls the black level. If set too low, pixels that are not supposed to be black will be black. If set too high, pixels that are supposed to be black are somewhat gray. The proper way to adjust this on a CRT TV is using a color bar with a bright pluge in the lower right hand corner. On a computer LCD display, the proper way to set this is to display a pattern with gray steps and adjust the brightness such that the first bar (black) is not visible, but such that the second bar is and is distinguishable from the third. On a LCD, this is not generally a problem in that when all zeros are sent to the shutters, it is as black as it is going to get. Some drivers will allow clipping of the digital signals at the low end, but all that really does is clip things that are not supposed to be black to black.

“Contrast” on a TV actually controls the gain of the luminance (black and white part of the picture). The contrast should be adjusted such that a gray step pattern does not saturate to white until the last step in the pattern. The second to last step should be distinguishable from the last. Again,in an all digital system, this should not be an issue, but could become an issue if one is still using a VGA system.

As an aside, the “Color” control is the chrominance gain and controls the color saturation whereas “tint” (only on NTSC) controls the phase of the color subcarrier (PAL and SECAM avoid this by changing reversing the phase on every other line)

Then comes the backlight issue. In most LCD systems, the Luminance is a function of both the backlight level and the individual shutters. The real definition of contrast can be simplified as a ratio of the display luminance to the amount of ambient light reflected from the display. In low light conditions, it is easy to get a high contrast display (>1000:1), whereas the same display in high ambient light may be lucky to achieve 3:1. The only way to drive up that contrast ratio is by improving the display luminance (either by increasing backlight brighness or by improving the transmittance of the LCD.


  1. Wiki: Operating system
  2. Wiki: Eye
  3. Wiki: Light-emitting diode
  4. Wiki: Liquid-crystal display
  5. Wiki: Pulse-width modulation
  6. TFT Central
  7. TFT Central: Pulse Width Modulation
  8. TFT Central: Flicker Free Monitor Database
  9. PC Monitors: Forum: Flicker-free monitors
  10. 巴哈姆特:【討論】來討論最近很夯的BENQ GW2450HM不閃屏
  11. Wiki: Cataract
  12. Wiki: Intraocular lens
  13. T17 討論區:[心得] BenQ VA液晶顯示器體驗會 之 謎思大挑戰
  14. Wiki: Liquid-crystal display: Vertical alignment (VA)
  15. Wiki: Liquid-crystal display: IPS LCD vs AMOLED
  16. Wiki: Liquid-crystal display: Twisted nematic (TN)
  17. bbs: How to adjust brightness/contrast with xorg/intel?

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