We use monitors as our main source of output display in computers. And with LCDs becoming really popular, have you ever wondered what they are made up of?
Well heres a small presentation i had made for my college sometime back.
Thought I should share it here so it can help others incase they need one.
You can contact me via PM or post in this thread if you want the original PPT of the same.
I have tried my best to replicate the same using page breaks. Hope you like it.
[break=Introduction & Definition]
What Is A Monitor?
This is the question which is pretty simple to answer as most of us who have seen a computer know what a monitor is. But do we know the real technical defination of the same?
A monitor or a display screen or computer monitor or computer video display is a device which is used to display signals generated by the computer as images on the screen.
It is also known as the “peripheral device which is used to display information to the userâ€.
It is also the most used forms of an output device to interact with the user irrespective of the task being performed like: working in an application, surfing the internet, playing games etc. by the use of graphical and textual means.
All these are the various definations of the monitor. However, there is no fixed one defination. All the functions mentioned above are pure facts as to how the monitors are useful to us.
Types Of Monitors
CRT Monitors – The most common type of monitor which is in use at most of the places these days.
LCD Monitors – Though costly, Liquid Crystal Display is a better alternative to CRT monitors.
TFT Monitors – They are also known as Thin Film Transistor LCD monitors.
[break=Some Important Terms]
Some Important Terms
Before we actually step into the technical aspect of montiors and LCDs, its important for us to know a few basic terms which will help us understand the topic better.
Pixel: Picture Element. The basic unit from which a video or computer picture is made. Essentially a dot with a given color and brightness value.
Resolution: The number of pixels per square inch on a computer screen. Resolution is expressed by identifying the number of pixels on the horizontal axis(rows) and the number on the vertical axis(columns) (Eg: 640x480, 800x600, 1024x768).
Aspect Ratio: The aspect ratio is the ratio of the width of the image to the height of the image. For most CRT based monitors the aspect ratio is 4:3. For wide screen LCD monitors, the aspect ratio is 16:9 (or sometimes 16:10 or 15:9).
DVI: Digital Visual Interface. DVI is a standard that defines the digital interface between digital devices such as projectors and personal computers.
Color Bit Depth: The number of bits used to describe the color of a single pixel.
[break=Screen Size]
Screen Size
Screen sizes are normally measured in inches from one corner to the corner diagonally across from it. It is measured diagonally as the earlier Television manufacturers wanted to make their television specifications sound more attractive. This system has stuck on since then.
Screen size measurement however, differs for CRT monitors and for LCD monitors. Popular sizes are 15â€, 17â€, 19†and 21â€.
For CRT monitors, screen size is measured diagonally from outside edges of the display casing as shown in the figure.
For LCD monitors, screen size is measured diagonally from the inside of the beveled edge.
[break=Connectors]
To display information on the monitor, the computer sends a signal to the monitor. This can either be Analog or digital.
Most CRT monitors require an input signal in Analog form .
This signal is generated by the video adapter which is also commonly known as the graphics card.
The D-Sub Connector or the Analog connector is shown in the picture.
The table below it shows the various pins and their purpose
As the analog connector doesn’t support digital output, there is a need for a special digital connector.This connector is called the DVI connector.
DVI Stands for Digital Video Interface.
It is based on TMDS (Transitional Minimized Differential Signaling)
A transmitter on the video adapter sends the digital information to a receiver in the monitor. TMDS takes the signal from the video adapter, determines the resolution and refresh rate that the monitor is using, and spreads the signal out over the available bandwidth to optimize the data transfer from computer to monitor.
The DVI connector is of two types:
DVI-digital (DVI-D) is a digital-only format. It requires a video adapter with a DVI-D connection and a monitor with a DVI-D input.
DVI-integrated (DVI-I) supports both digital and analog transmissions. This gives you the option to connect a monitor that accepts digital input or analog input.
[break=Color Depth]
Color Depth
The combination of the display modes supported by your graphics adapter and the color capability of your monitor determine how many colors it displays.
A display that operates in SuperVGA (SVGA) mode can display up to 16,777,216 (usually rounded to 16.8 million) colors because it can process a 24-bit-long description of a pixel. With a 24-bit bit depth, eight bits are dedicated to each of the three additive primary colors -- red, green and blue. This bit depth is also called true color because it can produce the 10,000,000 colors discernible to the human eye. A 16-bit display is only capable of producing 65,536 colors. Displays jumped from 16-bit color to 24-bit color because working in eight-bit increments makes things a whole lot easier for developers and programmers.
To create a single colored pixel, an LCD display uses three sub pixels with red, green and blue filters. Through the careful control and variation of the voltage applied, the intensity of each sub pixel can range over 256 shades.
Combining the sub pixels produces a possible palette of 16.8 million colors (256 shades of red x 256 shades of green x 256 shades of blue).
[break=LCD Monitors]
LCD Monitors
Liquid crystal display technology works by blocking light. An LCD is made of two pieces of polarized glass (also called substrate) that contain a liquid crystal material between them. A backlight creates light that passes through the first substrate. At the same time, electrical currents cause the liquid crystal molecules to align to allow varying levels of light to pass through to the second substrate and create the colors and images that you see.
Most LCD displays use active matrix technology.
A thin film transistor (TFT) arranges tiny transistors and capacitors in a matrix on the glass of the display. To address a particular pixel, the proper row is switched on, and then a charge is sent down the correct column. Since all of the other rows that the column intersects are turned off, only the capacitor at the designated pixel receives a charge. The capacitor is able to hold the charge until the next refresh cycle.
The other type of LCD technology is passive matrix. This type of LCD display uses a grid of conductive metal to charge each pixel. Although they are less expensive to produce, passive matrix monitors are rarely used today due to the technology's slow response time and imprecise voltage control compared to active matrix technology.
[break=LCD Features and Attributes]
LCD Features And Attributes
Native Resolution:
Well heres a small presentation i had made for my college sometime back.
Thought I should share it here so it can help others incase they need one.
You can contact me via PM or post in this thread if you want the original PPT of the same.
I have tried my best to replicate the same using page breaks. Hope you like it.
[break=Introduction & Definition]
What Is A Monitor?
This is the question which is pretty simple to answer as most of us who have seen a computer know what a monitor is. But do we know the real technical defination of the same?
A monitor or a display screen or computer monitor or computer video display is a device which is used to display signals generated by the computer as images on the screen.
It is also known as the “peripheral device which is used to display information to the userâ€.
It is also the most used forms of an output device to interact with the user irrespective of the task being performed like: working in an application, surfing the internet, playing games etc. by the use of graphical and textual means.
All these are the various definations of the monitor. However, there is no fixed one defination. All the functions mentioned above are pure facts as to how the monitors are useful to us.
Types Of Monitors
CRT Monitors – The most common type of monitor which is in use at most of the places these days.
LCD Monitors – Though costly, Liquid Crystal Display is a better alternative to CRT monitors.
TFT Monitors – They are also known as Thin Film Transistor LCD monitors.
[break=Some Important Terms]
Some Important Terms
Before we actually step into the technical aspect of montiors and LCDs, its important for us to know a few basic terms which will help us understand the topic better.
Pixel: Picture Element. The basic unit from which a video or computer picture is made. Essentially a dot with a given color and brightness value.
Resolution: The number of pixels per square inch on a computer screen. Resolution is expressed by identifying the number of pixels on the horizontal axis(rows) and the number on the vertical axis(columns) (Eg: 640x480, 800x600, 1024x768).
Aspect Ratio: The aspect ratio is the ratio of the width of the image to the height of the image. For most CRT based monitors the aspect ratio is 4:3. For wide screen LCD monitors, the aspect ratio is 16:9 (or sometimes 16:10 or 15:9).
DVI: Digital Visual Interface. DVI is a standard that defines the digital interface between digital devices such as projectors and personal computers.
Color Bit Depth: The number of bits used to describe the color of a single pixel.
[break=Screen Size]
Screen Size
Screen sizes are normally measured in inches from one corner to the corner diagonally across from it. It is measured diagonally as the earlier Television manufacturers wanted to make their television specifications sound more attractive. This system has stuck on since then.
Screen size measurement however, differs for CRT monitors and for LCD monitors. Popular sizes are 15â€, 17â€, 19†and 21â€.
For CRT monitors, screen size is measured diagonally from outside edges of the display casing as shown in the figure.
For LCD monitors, screen size is measured diagonally from the inside of the beveled edge.
[break=Connectors]
To display information on the monitor, the computer sends a signal to the monitor. This can either be Analog or digital.
Most CRT monitors require an input signal in Analog form .
This signal is generated by the video adapter which is also commonly known as the graphics card.
The D-Sub Connector or the Analog connector is shown in the picture.
The table below it shows the various pins and their purpose
As the analog connector doesn’t support digital output, there is a need for a special digital connector.This connector is called the DVI connector.
DVI Stands for Digital Video Interface.
It is based on TMDS (Transitional Minimized Differential Signaling)
A transmitter on the video adapter sends the digital information to a receiver in the monitor. TMDS takes the signal from the video adapter, determines the resolution and refresh rate that the monitor is using, and spreads the signal out over the available bandwidth to optimize the data transfer from computer to monitor.
The DVI connector is of two types:
DVI-digital (DVI-D) is a digital-only format. It requires a video adapter with a DVI-D connection and a monitor with a DVI-D input.
DVI-integrated (DVI-I) supports both digital and analog transmissions. This gives you the option to connect a monitor that accepts digital input or analog input.
[break=Color Depth]
Color Depth
The combination of the display modes supported by your graphics adapter and the color capability of your monitor determine how many colors it displays.
A display that operates in SuperVGA (SVGA) mode can display up to 16,777,216 (usually rounded to 16.8 million) colors because it can process a 24-bit-long description of a pixel. With a 24-bit bit depth, eight bits are dedicated to each of the three additive primary colors -- red, green and blue. This bit depth is also called true color because it can produce the 10,000,000 colors discernible to the human eye. A 16-bit display is only capable of producing 65,536 colors. Displays jumped from 16-bit color to 24-bit color because working in eight-bit increments makes things a whole lot easier for developers and programmers.
To create a single colored pixel, an LCD display uses three sub pixels with red, green and blue filters. Through the careful control and variation of the voltage applied, the intensity of each sub pixel can range over 256 shades.
Combining the sub pixels produces a possible palette of 16.8 million colors (256 shades of red x 256 shades of green x 256 shades of blue).
[break=LCD Monitors]
LCD Monitors
Liquid crystal display technology works by blocking light. An LCD is made of two pieces of polarized glass (also called substrate) that contain a liquid crystal material between them. A backlight creates light that passes through the first substrate. At the same time, electrical currents cause the liquid crystal molecules to align to allow varying levels of light to pass through to the second substrate and create the colors and images that you see.
Most LCD displays use active matrix technology.
A thin film transistor (TFT) arranges tiny transistors and capacitors in a matrix on the glass of the display. To address a particular pixel, the proper row is switched on, and then a charge is sent down the correct column. Since all of the other rows that the column intersects are turned off, only the capacitor at the designated pixel receives a charge. The capacitor is able to hold the charge until the next refresh cycle.
The other type of LCD technology is passive matrix. This type of LCD display uses a grid of conductive metal to charge each pixel. Although they are less expensive to produce, passive matrix monitors are rarely used today due to the technology's slow response time and imprecise voltage control compared to active matrix technology.
[break=LCD Features and Attributes]
LCD Features And Attributes
Native Resolution:
- Unlike CRT monitors, LCD monitors display information well only at the resolution they are designed for.
- If you change the resolution settings, the LCD scales the image and the quality suffers.
- Native resolutions are typically:
- 17 inch = 1024x768
- 19 inch = 1280x1024
- 20 inch = 1600x1200
Viewing Angle:- When you look at an LCD monitor from an angle, the image can look dimmer or even disappear.
- Colors can also be misrepresented. To compensate for this problem, LCD monitor makers have designed wider viewing angles.(Not the same as widescreen displays).
- The visible angle of the screen is increased.
- Ideally a LCD with a viewing angle of 120 to 170 degrees is preferred.
Contrast Ratio:
The contrast ratio rates the degree of difference of an LCD monitor's ability to produce bright whites and the dark blacks. The figure is usually expressed as a ratio, for example, 500:1. Typically, contrast ratios range from 450:1 to 600:1.
Response Rate:- The speed with which the monitor’s pixels can change colors.
- Having a faster response time is better as it reduces the ghosting effect when an image moves across the screen.
Adjustability:- LCD monitors have much more flexibility for positioning the screen the way you want it.
- LCD monitors can swivel, tilt up and down, and even rotate from landscape (with the horizontal plane longer than the vertical plane) to portrait mode (with the vertical plane longer than the horizontal plane).
- This is mainly because they are lightweight and thin, most LCD monitors have built-in brackets for wall or arm mounting.
- Some of the latest LCD monitors have other features included such as integrated speakers, built-in Universal Serial Bus (USB) ports and anti-theft locks.
[break=LCD’s Vs. CRT’s]
LCD's Vs. CRT's
LCD's- Require less power
- The average is about 45 watts for a 19-inch LCD display.
- LCDs also produce less heat.
- Smaller and weigh less
[*]An LCD monitor is significantly thinner and lighter than a CRT monitor, typically weighing less than half as much. - More adjustable
- Less eye strain
[*]LCD displays turn each pixel off individually, they do not produce a flicker like CRT displays do. In addition, LCD displays do a better job of displaying text compared with CRT displays.
CRT's- Less expensive
[*]Although LCD monitor prices have decreased, comparable CRT displays still cost less. - Better color representation
- More accurate than LCD displays.
- More responsive
- CRT monitors have had fewer problems with ghosting and blurring because they redrew the screen image faster than LCD monitors.
- Multiple resolutions
- If you have a need to change your display's resolution for different applications, CRT is better because LCD monitors don't handle multiple resolutions as well as CRTs.
- More rugged
[*]Although they are bigger and heavier than LCD displays, CRT displays are also less fragile and harder to damage.
