Display Devices Flashcards
A flat panel screen that uses a liquid crystal solution sandwiched between two polarizing filters and glass panels
LCD liquid crystal display
A flat panel screen that uses an organic substance as the semiconductor material in LEDs
OLED organic light emitting diode display
A flat panel screen that uses small cells filled with noble gases and phosphors to create color
Plasma
Contains a large vacuum tube with a flat end covered in phosphors
CRT Cathode Ray Tube
Uses a grid of horizontal and vertical wires with an LCD element at each intersection
Passive Matrix
There is a transistor at each intersection which controls the light for each pixel
Active Matrix
What are the two technologies to polarize the liquid crystals in an LCD?
Passive & Active Matrix
What are three ways of illuminating an LCD panel
Reflective
Transmissive
Transflective
A mirror behind the panel bounces ambient light back to the user
Reflective LCD backlighting
A backlight behind the panel shines light toward the user, making the display readable in low light situations
Transmissive LCD backlighting
Uses both a backlight and a partially reflective layer between the backlight and the LCD display to capture ambient light
Transflective LCD backlighting
What is the purpose of a screen inverter in a laptop?
The inverter takes DC from the motherboard and converts it into AC for the backlighting.
Three common types of liquid-crystal technology
TN (Twisted Nematic)
IPS (In-Plane Switching)
VA (Vertical Alignment)
Use crystals which are horizontally aligned with the screen, best viewing angles and able to produce the most accurate colors. Increased power consumption and slower response times
IPS: In-Plane Switching displays
Displays that have crystals which are vertically aligned when there is no electrical current and horizontally aligned when current is applied
VA: Vertical Alignment displays
Newer technology that uses a single chip with a reflective surface composed of thousands of tiny mirrors corresponding to individual pixels
Digital Light Processing (DLP)
Older technology that uses mirrors and prisms to direct light through LCD panels and towards the projector’s lens
LCD
LCD projector advantages
Colors are more accurate. This is due to a clear section into the DLP color wheel. It boosts brightness, but reduces color saturation.
Slightly sharper images than the DLP at the same resolution.
Produces a brighter image than DLP using the same wattage lamp.
DLP projector advantages
Smaller and more portable due to the use of the mirror chip instead of panels.
Produces deeper blacks than LCD, giving them a higher contrast.
Less pixelation, allowing for smoother motion graphics.
Higher reliability due to fewer moving parts.
A 3D display containing stereoscopic displays, one for each eye, along with stereo output. Motion tracking uses internal gyroscopes and accelerometers, and may include more advanced features such as eye tracking sensors
Virtual reality systems
Allow you to perceive your surroundings normally, but augment it with images, sounds, or other sensory information provided by the computer.
AR augmented reality
The measurement describing the width and height ratio of an image on the screen, expressed in width:height format
Aspect Ratio
A measurement of the intensity of the energy output of a visible light source with pure white being the max and pure black the minimum.
Brightness
A measurement of how often the display image is updated per second. It is expressed in hertz (Hz)
Refresh Rate
What controls the monitors refresh rate?
GPU
The number of pixels (individual points of light or color) displayed on a screen. The measurement is documented as horizontal pixels x vertical pixels.
Resolution
What determines how sharp an image appears to the human eye
size of display and resolution
Often expressed as pixels per inch (ppi) in a display’s statistics
Pixel Density
Higher ________ provides more image detail, while high ________ provides a sharper image
resolution, pixel density
Which display port is not hot-swappable?
VGA
This mode loads minimal video drivers and uses a low-resolution setting (640 × 480), allowing you to diagnose and fix video card problems
Windows Advanced Boot menu to boot into VGA mode
What can you do if you can see the initial boot screen when you turn on your computer, but it goes blank once Windows starts to load?
boot into Safe Mode and use System Restore to repair Windows
What might cause display artifacts?
Overheated Graphics Card
Troubleshoot “no image on screen”
Caused by a dead monitor or no signal being received from the computer
Troubleshoot “overheat shutdown”. Image on the display may appear garbled or flicker
Clean inside of the case and ensure all fans are working. Replace video card if problem persist.
Troubleshoot “dead pixels”
Replace the monitor with a known-good unit.
Troubleshoot “artifacts”
Replace the video card with a known-good card.
Troubleshoot “Color patterns incorrect”
If display colors are incorrect only after PC loads windows, then check display settings. Otherwise, it is a hardware problem.
Troubleshoot “flickering”
Make sure that all your cables are seated properly. If that does not fix the issue, replace the cables. Can be caused if the refresh rate is not compatible with the high resolution. Increase the refresh rate.
Troubleshoot “distorted image”
Caused by power issues. Replace the power cable
