IPS vs. LPS Screen

IPS ((In-Plane Switching technology): was originally developed by Hitachi and had been in use from the mind nineties. Earlier to this twisted nematic (TN) technology was used to make panels for monitors. Hitachi introduced the IPS technology for liquid crystal display (LCD) panels. This technology was used to overcome limitations faced by TN matrices, which included slow response, small viewing angles and low quality colour reproduction. The new technology of In-Plane Switching (IPS) introduced arrangement and switching of the molecules of the liquid crystal (LC) layer between the glass substrates in a plane parallel to these glass plates. This technology made a lot improvement in the colours schemes and the resolution in the technology used in twisted nematic (TN) monitors. It provided a better viewing angles and better resistance to touching. Hitachi went on making improvements in this technology making the IPS displays quite popular among the users. 

In 2010, Samsung emerged as Hitachi's main competitor by introducing yet another new technology called PLS (Plane-to-Line Switching). The intention of Samsung was quite clear. It wanted to supersede and overtake the conventional IPS technology introduced by Hitachi in the mid nineties. PLS technology introduced by Samsung became the company's wide-viewing angle technology. Samsung has claimed that the PLS technology has further improved the viewing angle. It claims to have increased 10 percent increase in brightness. The company also boasts of 15 per cent decrease in the production costs. There is increase in image quality and in the flexibility of the panel.

Both the IPS and PLS technologies are almost similar, and it is very difficult for the common user to know as to which technology has been used in the display screens. However, the PLS screens are known to be brighter and have better viewing angles. The PLS panels do not change colour on touching them. They do not leave a trail when the user drags his or her finger across the panel. The difference in both the panels is more of a technical and practical value. They are very small and mostly insignificant in the real life situations.

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How to Fix a Stuck Pixel on an LCD Monitor

If your LCD screen has a stuck or dead pixel (a point on the screen that is always lit or always dark), it is usually due to a transistor malfunction or uneven distribution of liquid in the liquid crystal display (TFT LCD). This can often be fixed.

Steps....

Software Method

1. Try running pixel fixing software (see Sources and Citations). Stuck pixels can often be re-energized by rapidly turning them on and off. If this fails, complete the following steps.

Pressure Method

1. Turn off your computer's monitor.
2. Get yourself a damp washcloth, so that you don't scratch your screen.
3. Take a household pen, pencil, screwdriver, or some other sort of instrument with a focused, but relatively dull, point. A very good tool would be a PDA stylus.
4. Fold the washcloth to make sure you don't accidentally puncture it and scratch the screen.
5. Apply pressure through the folded washcloth with the instrument to exactly where the stuck pixel is. Try not to put pressure anywhere else, as this may make more stuck pixels.
6. While applying pressure, turn on your computer and screen.
7. Remove pressure and the stuck pixel should be gone. This works as the liquid in the liquid crystal has not spread into each little pixel. This liquid is used with the backlight on your monitor, allowing different amounts of light through, which creates the different colors.

Tapping Method

1. Turn on the computer and LCD screen.
2. Display a black image, which will show the stuck pixel very clearly against the background. (It is very important that you are showing a black image and not just a blank signal, as you need the backlighting of the LCD to be illuminating the back of the panel).
3. Find a pen with a rounded end. A Sharpie marker with the cap on should be fine for this.
4. Use the rounded end of the pen to gently tap where the stuck pixel is - not too hard to start with, just enough to see a quick white glow under the point of contact. If you didn't see a white glow, then you didn't tap hard enough, so use just slightly more pressure this time.
5. Start tapping gently. Increase the pressure on the taps gradually for 5-10 taps until the pixel rights itself.
6. Display a white image (an empty text document is good for this) to verify that you haven't accidentally caused more damage than you fixed.

Tips....

• If the pressure and tapping don't work directly on the stuck pixel, start moving outward around the stuck pixel. If you see the pixel flicker while doing this then you know where you can focus the pressure and tapping techniques rather than directly on the pixel.
• Many people report success with this technique but these instructions won't work in every case. It may take a few attempts to make sure you are pressing exactly on the stuck pixel.
• These instructions will fix "stuck" pixels, not "dead" ones. Dead pixels appear black while stuck pixels can be one constant color like red, blue or green.
• An alternative, but similar technique involves gently massaging the stuck pixel with a warm damp (not wet) soft cloth.
• Alternative technique to tapping: Using a rounded pencil eraser, push with moderate pressure into screen at stuck pixel.
• If these instructions don't work, you can hopefully get the monitor replaced through your manufacturer. If your monitor falls under the specifications of replacement, get in contact with the manufacturer to set up replacement plans.
  

Warning....

• Do not attempt to open the monitor as it will void the warranty and the manufacturer will not replace it.
• Make sure you don't get any electrical equipment wet or it may break.
• Some people claim that touching the screen can cause more pixels to become stuck, although this has not been proven.

  

• Sub-Pixel Layers
  LCD Displays are composed of multiple layers. Each layer is separated by ve ry small glass spacers. These spacers and the individual layers are very delicate. Rubbing an LCD panel with a finger or even a cloth can cause the spacers to break and cause further issues beyond the original pixel fault. As such most repair technicians with service certifications are trained not to use the rub or tap methods - use them at your own risk.
• Most LCD manufacturer warranties for LCD displays will cover replacement of the panel when the display reaches a certain number of pixel anomalies. These warranties however generally will not cover damage caused by rubbing the screen so use extreme caution and contact the manufacturer before proceeding to see if you qualify for repair or replacement.

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What is a CRT Monitor?

CRT stands for cathode ray tube, describing the technology inside an analog computer monitor or television set. A CRT monitor or TV is readily recognizable by its bulky form. LCD monitors and plasma television sets, or flat panel displays, use newer digital technologies.

The CRT monitor creates a picture out of many rows or lines of tiny colored dots. These are technically not the same thing as pixels, but the terms are often used interchangeably. The more lines of dots per inch, the higher and clearer the resolution. Therefore 1024 x 768 resolution will be sharper than 800 x 600 resolution because the former uses more lines creating a denser, more detailed picture. Higher resolutions are important for displaying the subtle detail of graphics. For text, resolution isn't as critical.

But how do those colored dots appear on the screen?

Inside a CRT monitor is a picture tube that narrows at the rear into a bottleneck. In the bottleneck is a negative charged filament or cathode enclosed in a vacuum. When electricity is supplied, the filament heats up and a stream or "ray" of electrons pour off the element into the vacuum. The negatively charged electrons are attracted to positively charged anodes which focus the particles into three narrow beams, accelerating them to strike the phosphor-coated screen. Phosphor will glow when exposed to any kind of radiation, absorbing ultraviolet light and emitting visible light of fluorescent color. Phosphors that emit red, green and blue light are used in a color monitor, arranged as "stripes" made up of dots of color. The three beams are used to excite the three colors in combinations needed to create the various hues that form the picture.

To precisely direct the beams, copper steering coils are used to create magnetic fields inside the tube. The fields move the electron beams vertically or horizontally. By applying varying voltages to the steering coils, a beam can be positioned at any point on the screen. Each image is painted on the screen -— and repainted -- several times each second by scanning the electron beams across the screen at incredible rates. This must be done even when the picture being displayed is unchanging, because the phosphor only glows for a very short time.

The refresh rate indicates how many times per second the screen is repainted. Though monitors differ in their capabilities, lower resolutions normally have higher refresh rates because it takes less time to paint a lower resolution. Therefore a setting of 800 x 600 might have a refresh rate of 85Hz, (the screen will be repainted or refresh 85 times per second), while a resolution setting of 1024 x 768 may have a refresh rate of 72Hz. Still higher resolutions usually have refresh rates closer to 60Hz. Anything less than 60Hz is generally considered inadequate, and some people will detect "flicker" even with acceptable refresh rates. Generally speaking, high-end monitors have higher refresh rates overall than lower-end models.Another specification regarding CRT monitors is "dot pitch" which relates to the tightness or sharpness of the picture. A lower dot pitch such as .25 is preferable over a higher dot pitch. In the heydey of the CRT monitor this was an issue because some models were sold with .32 dot pitch, resulting in "fuzzy" text. By the end of the CRT era, virtually all displays had .28 or better and today's CRT monitors can have dot pitches as low as .21.

The CRT monitor comes in 15-inch to 21-inch sizes (38 — 53 cm) and larger, though the actual viewing screen is about 1 inch (2.5 cm) smaller than the rated size. Screens are measured diagonally from corner to corner, including the case.

Tried, true, dependable and economical, CRT technology ruled for decades before its dethroning in the late 1990s - early 2000s. Negatives of the CRT include radiation emission, high power consumption, weight and bulk.

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