LED Monitor is an LCD monitor equipped with LED (Light Emitting Diode) backlight. The previous version of LCD is using the CCFL (Cold Cathode Fluorescent Lamp) backlight. Before this LCD Monitor era, we are familiar with the CRT (Cathode Ray Tube) monitor.
Some well known advantage using LED monitor :
- Lower power consumption.
- Saving space, due to it's slimmer and thinner design.
- Produce less environmental pollution on disposal.
- We get higher Contrast Ratio
Several sample of LED Backlight Screen implementation :
ATM
Notebook
Cellphone
PC Monitor
TV
and many more...
But in this Blog, we'll only see LED backlight screen references from PC monitors and TVs.This video will show you the basic of how LCD Monitor works.
GENERAL TERMS
Size and Resolution
Size refers to the dimension measured diagonally. Size is stated in " mark or INCH.
Example : 21.5" or 21.5 inch, etc.
Resolution refers to the amount of pixels in a monitor.
Example : 1920x1080, 1366x768, etc.
1920x1080 means that the monitor has 1920 (one thousand nine hundred and twenty) pixels in one row from right to left and 1080 pixels in one row from bottom to top of the monitor's screen.
Aspect Ratio
Aspect Ratio is the size ratio of your monitor's width and height.
Example :
- 4 : 3 in most CRT monitors.
- 16 : 9 in latest Full HD monitors, etc.
Full HD
Stands for Full High Definiton.
Full HD refers to the 1920x1080 pixels resolution.
Usually written Full HD or 1080p in the tech spec.
Pixel
Single tiny dot that mostly contain 3 sub-pixels (red-green-blue). Except for the SHARP's Quattron technology that has 4 sub-pixels including yellow sub-pixel. This pixel can perform a specific color. Pixels will form pictures in the monitor's screen.
Pixel Diameter
Diameter that indicate a pixel size. 23" Full HD monitor surely has bigger pixel diameter than the 21.5" Full HD (1920x1080) monitor.
Example :
21.5" Full HD monitor has 0.248mm pixel diameter.
23" Full HD monitor has 0.265mm pixel diameter.
Defective Pixel
Defective Pixels are pixels that aren't performing as expected.
There are several kind of defective pixels, but in this blog, we'll go further with the dead and stuck pixels.
In a dead pixel, all three sub-pixels are permanently off. Dead pixels can result from similar manufacturing anomalies as stuck pixels, but may also occur from a non-functioning transistor resulting in complete lack of power to the pixel.
Dead pixels are much less likely to correct themselves over time or be repaired through any of several popular methods
Stuck pixels, unlike dead pixels, have been reported by LCD screen owners to disappear, and there are several popular methods purported to fix them :
- Gently rubbing the screen (in an attempt to reset the pixel). Please perform this action with the help of microfiber cloth.
- Cycling the color value of the stuck pixel rapidly (in other words, flashing bright colors on the screen). You can use Dead Pixel Tester Software to do this.
- Simply tolerating the stuck pixel until it disappears (which can take anywhere from a day to years).
Sample of a dead green sub-pixel
Please visit SOFTPEDIA if you want to download DEAD PIXEL TESTER Software for your monitor or you can GOOGLE to find others.
Please visit WIKIPEDIA if you want to read further about DEFECTIVE PIXEL.
Or you can GOOGLE to find other articles about it.
Backlight Bleed
The entire surface of an LCD panel is backlit from behind by a light source (CCFL or LED) and the LCD blocks out the light that is not needed when displaying a particular image. Backlight bleeding occurs when this light is not 100% blocked, allowing excess light to "bleed" through the LCD.
This backlight bleeding issue leaves spots of lighter areas on a dark or black background. Unfortunately, almost all LCD panels suffer from at least a small amount of backlight bleed because the opacity of LCD panels is not enough to block all light, though it only causes problems if it can be easily detected by the human eye.
Backlight Bleeding sample
Please visit PCHARDWAREHELP for further reading about backlight bleeding.
cd/m2
Stands for Candela per meter square.
This symbol is used to indicate the Light Intensity or Brightness of a monitor.
Example : 250 cd/m2 , etc.
You can adjust the light intensity of your monitor in the Brightness menu.
Contrast Ratio
Is the indicator used to show the monitor's pixel ability to perform a White Bright Dots and Black Dark Dots. Usually written in * : 1 format.
Example : 1,000,000 : 1, 5,000,000 : 1, 5M : 1 etc.
We often see STATIC and DYNAMIC Contrast Ratio in the tech spec.
STATIC
We'll get Static Contrast Ratio when the contrast ratio is measured at the same time using the same scene of the monitor.
DYNAMIC
We'll
get Dynamic Contrast Ratio when the contrast ratio is measured not
necessarily at the same time or in the same scene of the monitor.
A measurement of the whitest white in the brightly lit scene compared to the darkest dark in the low-lit scene results in the dynamic contrast ratio specification.
Response Time
Is the time written in the spec to indicate the ability of a pixel to change from certain state to the other. Example to change from color A to color B, etc.
Usually written in *ms (millisecond) and in Hz (hertz)
Example : 5ms, 2ms, etc.
Lower ms is better. Higher Hz is better.
There are many kind of Response Time
measurement. The measurement process itself can be different from one
vendor to the other. Some of the most familiar are :
Grey to Grey measurement.Means that the pixel response time is measured when pixel is in GREY color position and gradating to WHITE color and then gradating back to GREY color.
Black to Black measurement.
Means that the pixel response time is measured when pixel is in BLACK color position and gradating to WHITE color and then gradating back to BLACK color.
Black to White or White to Black measurement.
Means that the pixel response time is measured when pixel is in BLACK/WHITE color position and gradating to WHITE/BLACK color.
The gradating process itself will through millions of colors and will be influenced by the monitor's Color Support, Graphic Engine and Other classified supporting components.
Black to White or White to Black measurement will produce half the time of Black to Black measurement, because it's only half way to go than the Black to Black measurement.
Black to Black measurement will produce higher ms response time then the Grey to Grey measurement.
Example : You got 5ms response time using the Black to Black method, but you can get 2ms using the Grey to Grey method.
That's why we mostly see the Grey to Grey measurement result in the monitor spec. This is also a marketing strategy by the monitor vendors to get lower response time in the spec to attract the consumers. This measurement is usually stated in the spec. Example : 5ms GtG, 5ms G2G, 5ms grey to grey, etc.
Panels
Several Known Panels Technology :
TN ( Twisted Nematic )
The most common LCD panel.
Has a low production cost and has a good RESPONSE TIME.
Not doing very well in the VIEWING ANGLE segment.
Vertical Alignment ( VA )
This panel produce a better COLOR REPRODUCTION and VIEWING ANGLE compare to the TN panel. Two well known VA panel are Multi-domain Vertical Alignment ( MVA ) developed by FUJITSU and Patterned Vertical Alignment ( PVA ) developed by joint venture company SAMSUNG and SONY.
Advanced Fringe Field Switching ( AFFS )
This is an LCD technology derived from the IPS by Boe-Hydis of Korea. Known as fringe field switching (FFS) until 2003, advanced fringe field switching is a technology similar to IPS or S-IPS offering superior performance and colour gamut with high luminosity. Colour shift and deviation caused by light leakage is corrected by optimizing the white gamut, which also enhances white/grey reproduction. AFFS is developed by Hydis Technologies Co., Ltd, Korea (formally Hyundai Electronics, LCD Task Force).
In 2004, Hydis Technologies Co., Ltd licensed its AFFS patent to Japan's Hitachi Displays. Hitachi is using AFFS to manufacture high end panels in their product line. In 2006, Hydis also licensed its AFFS to Sanyo Epson Imaging Devices Corporation.
Hydis introduced AFFS+ which improved outdoor readability in 2007
Advanced Super View ( ASV )
Advanced super view, also called axially symmetric vertical alignment was developed by SHARP. It is a VA mode where liquid crystal molecules orient perpendicular to the substrates in the off state. The bottom sub-pixel has continuously covered electrodes, while the upper one has a smaller area electrode in the center of the subpixel. When the field is on, the liquid crystal molecules start to tilt towards the center of the sub-pixels because of the electric field; as a result, a continuous pinwheel alignment (CPA) is formed; the azimuthal angle rotates 360 degrees continuously resulting in an excellent viewing angle. The ASV mode is also called CPA mode.
Plane Line Switching ( PLS )
A new technology developed by SAMSUNG is Super PLS, which bears similarities to IPS panels and touts improved viewing angles and image quality, increased brightness and lower production costs. PLS technology first debuted in the PC display market with the release of the Samsung S27A850 and S24A850 monitors in September 2011.
In-Plane Switching ( IPS )
In-Plane Switching was developed by Hitachi Ltd. in 1996 to improve on the poor viewing angle and the poor color reproduction of TN panels at that time. Its name comes from the main difference from TN panels, that the crystal molecules move parallel to the panel plane instead of perpendicular to it. This change reduces the amount of light scattering in the matrix, which gives IPS its characteristic wide viewing angles and good color reproduction.
Initial iterations of IPS technology were plagued by slow response time and a low contrast ratio but later revisions have made marked improvements to these shortcomings. Because of its wide viewing angle and accurate color reproduction (with almost no off-angle color shift), IPS is widely employed in high-end monitors aimed at professional graphic artists, although with the recent fall in price it has been seen in the mainstream market as well. IPS technology was sold to Panasonic by Hitachi. Hitachi and LG is not playing game in developing their IPS panel.
HITACHI : Super TFT (IPS) 1996, Super-IPS 1998, Advanced Super IPS 2002, IPS Provectus 2004, IPS Alpha 2008, IPS Alpha Next Gen 2010.
LG : Super IPS 2001, Advanced Super IPS 2005, Horizontal IPS 2007, Enhanced IPS 2009, Professional IPS 2010, Advanced High Performance IPS 2011.
The most common panel untill now is TN, PVA and IPS. We'll see which panel technology will last. Or maybe there's going to be a new breakthrough in panel technology with a new naming involve.
This Video will show you the difference between IPS and TN Panel.
For further reading about panels technology, You can visit WIKIPEDIA and PCHARDWAREHELP
Ports/Connectors
Usual ports on PC Monitors :
Analog RGB/D-Sub/Standard VGA 15 pins
DVI-I (Digital Video Interface Integrated)
Integrated : Analogue and Digital
Integrated : Analogue and Digital
DVI-D (Digital Video Interface Digital)
Digital only
Digital only
HDMI (High Definition Multimedia Interface)
available in several version : 1.3, 1.4, etc.
Component : Video Green(Y), Blue(PB), Red(PR), Audio White and Red
Composite/AV : Video Yellow, Audio White and Red
available in several version : 1.3, 1.4, etc.
LED TV Ports sample :
Component : Video Green(Y), Blue(PB), Red(PR), Audio White and Red
Composite/AV : Video Yellow, Audio White and Red
VGA Card Ports sample :
DisplayPort - HDMI - DVI-I
If your Monitor and your VGA connectors doesn't match, you can use a converter to do things right. Please give attention to the Male or Female pins. Below is a few sample of them.
D-Sub to DVI-D Dual Link Converter
D-Sub to HDMI Converter
Dual Link DVI-D to HDMI Converter
Single Link DVI-D to HDMI Converter
DVI-I to D-Sub Converter
DVI-D Dual Link to HDMI Converter Cable
D-Sub to HDMI Converter Cable
and many other...
Viewing Angle
Written in ° (degree)
Indicates the maximum viewing angle provided by the monitor before the picture become unseen.
Example : 160°, etc.
IPS Panel has a better Viewing Angle than most TN Panel.
IPS Panel has a better Viewing Angle than most TN Panel.
Color Support/Color Gamut/Gamut Level
Indicates the maximum color supported by the monitor.
Written in % (percentage)
Example : 75%, 82%, etc
or usually written in the spec as certain rate.
Example : support 16.7M (million) color, etc.
or usually written in the spec as certain rate.
Example : support 16.7M (million) color, etc.
MAINTENANCE
Daily Use Maintenance :- Give your monitor a spare space enough for air circulation.
- Don't touch the screen (unless it's a touch screen monitor). Touching the screen can leave finger prints, dirt, grease, etc.
- Set the monitor to shut down if you plan a long time stand by. 'Blinking light' is not recommended for a long time stand by.
- Don't forget to turn off your monitor when the system is shut down.
- Arrange the monitor distance with your Speakers. Although many statement says there's no direct impact on placing speakers near LCD monitor, just play safe considering there are many metal components that taking place inside your monitor. Also not all Speakers are already magnetically shielded.
- It's better not to smoke in front of the monitor, because the smoke's chemical content in a certain period of time can give a negative impact to the screen.
- Arrange the monitor rest time.
- Clean the monitor casing and monitor stand using the microfiber cloth (glasses cloth) or soft cotton. Add a little drinking water if you wish. Squeeze the cloth or cotton until the water doesn't drop. This is important when cleaning near the air holes (usually small gaps at the back of the monitor for air circulation) to prevent water get inside your monitor.
- Use the small and clean paint brush to clean your monitor's ports from trapped dust. Avoid using water in this area.
- Clean the screen using microfiber cloth. If dirt or grease and other material present in your screen, you can add a little drinking water and squeeze the cloth until the water doesn't drop. This action will prevent the water slip between you screen and the monitor casing.
- Before cleaning, the monitor has to be in shut down position.
- Don't press the screen to hard while cleaning the screen's surface.
- Don't use any unapproved chemical materials (such as soap, alcohol, etc) for cleaning your monitor.
- Don't spray directly to your monitor, specially the screen and air circulation gaps. If you can't control the fluid being sprayed, fluid might slip inside your monitor.