CompTIA A+ Certification 901 chp 8 Display Devices
List the three most common different liquid-crystal technologies LCD monitors use:
*Twisted Nematic *In-Plane Switching (ISP) *Vertical Alignment (VA)
What should you do if there is a video card and an onboard video port?
You must disable one or the other in the BIOS/UEFI
what are dead pixels?
when pixels won't change colors. a voltage issue
OLED Displays (Organic Light Emitting Diode)
•Thinner and lighter than LCDs - no glass needed •The organic compound provides no Back-lighting needed to see in low-lighting conditions •Used for smaller mobile devices due to cost *Not as bright back-lit LCDs *Best picture quality because it's ability to produce deep, dark blacks. *Have a wide 160 degree viewing angle *A very high contrast ratio of 1.000.000.1 and quick response time *Can be slightly curved at the sides *More expensive than LCDs *Have problems with the material used to produce the color blue. *It degrades much faster than the other colors *This effects the display's color balance /reduces it's overall brightness.
OLED (Organic Light Emitting Diode) display Substrate (Structure and framework)
*The substrate, which acts as the structural framework *red, green, blue tinted plastic layers are added to the substrate to produce color
LCD (Liquid Crystal Display)
*Uses billions of liquid crystal molecules solution *The liquid crystals are sandwiched two polarizing filters and glass panels *Using [electrical currents] which straightens and twist them to achieve the desired color
Plasma tv
*Uses noble gases and phosphors to create color *An [electrical current] is applied to the gas *Then a tiny bit of plasma (charged gas) illuminates a pixel
OLED (Organic Light Emitting Diodes)
*Uses organic substance as semiconductor material in LEDs *Using [electrical currents], protons move through the organic substance and emit a bright light *unlike LEDs, which uses an array of individual LED bulbs *OLED uses a series of thin, light emitting films. *OLED are more common in laptops
OLED (Organic Light Emitting Diode) display cathode electrons, anode electrons,
*anode draws electrons *cathode provides electrons
Blank monitor troubleshooting
*chk power *data cable *use windows advanced boot menu. *chk card drivers *chk device manager
Digital Light Processing (DLP) display projector technology
*the newer technology *Uses the a single chip *Uses reflective surface composed of thousands of tiny mirrors corresponding to individual pixels controlling the amount of light. *Projects colors by passing the light from the lamp through a rotating wheel with Red, Green, and Blue filters.
OLED (Organic Light Emitting Diode) display organic layer
*two layers with the organic layer: *conducting layer (in which the electrons move) *emissive layer (which produces light)
what is keystone button use for on projectors?
distorted geometry
Aspect ratio explained
The relationship of width to height in a picture or shape. 16:9 4:3 used mostly by older TVs
What might cause display artifacts?
Overheated graphics card
when adding a second display monitor on a laptop, how can you scroll through to choose which monitor to use?
By pressing the FN key + the appropriate # key which typically has a picture of a laptop and a box(monitor) behind it.
In LCDs, How are the red, green, or blue colors created for each pixel?
Billions of liquid crystal molecules are constantly and independently being very rapidly pulsed on/off at different rate of power.
Which display issues does running a screen saver help prevent?
Burn-in Dead pixels
what causes phosphor?
Burn-in or permanent image appear on screen
Windows display settings
By default, Windows uses the optimal display setting based on the graphics card and display device you have installed.
Which display projector technology has less pixilation, allowing for smoother motion graphics?
DLP(Digital Light Processing)
If you connect an external monitor to your laptop, you must configure it with identical display settings to the internal screen. TRUE or FALSE
FALSE
If you have a DVI monitor and a VGA graphics port, you can't install your monitor. TRUE or FALSE
FALSE
If you have a blank monitor screen, it is most likely due to monitor failure. TRUE or FALSE
FALSE
LCD monitors suffers from flicker (redraw). TRUE or FALSE
FALSE, LCD monitors often have a standard refresh rate that locked at 60 Hz and isn't adjustable.
VGA connections are designed to be hot-swappable. TRUE or FALSE
FALSE, you should power down before connecting a VGA monitor
which LCD (Liquid Crystal Display) technology produces the more accurate colors?
IPS In-Plane Switching)
If you are concerned about security and don't wan't your laptop screen easily viewed by others, what type of display should you select?
TN (Twisted Nematic)
List the three prominent technologies used for modern display devices for computers.
"They all need an [electric current] for them to work" *LCD (Liquid Crystal Display) *OLED (Organic Light Emitting Diodes) *Plasma
What is Active Matrix LCD?
*Active Matrix LCD are always backlit *This consists of transistors behind each pixel that stimulate electrodes that rearrange the liquid crystals. *Transistors require less electrical current to control pixels. *Allowing the current to be switched on/off more frquently *Improving screen refresh time *Provides a better image resolution and smoother graphic motions than passive matrix *But more expensive *LCD Inexpensive panels often suffer from reduced contrast and poor black levels when compared to other display technology , such as Plasma.
LCD display projectors technology
*An older technology *Uses mirrors and prisms to direct light *Primary colors are Red, Green, and Blue transparent glass panels *Three LCD panels *Individual pixels are opened/closed to allow light through or block it *similar to an old slide projector
when Display devices comparing, what should you take into effect?
*Analog or digital connection *Aspect ratio *Brightness *Filters *Refresh rate *Resolution
Filters explained
*Attached or applied to the surface of a display to reduce glare *can be permanently installed or purchased as an accessory *Also reduce the viewing angle of the display *advantage is it decreases people's ability to surreptitiously view the display from the side, increasing privacy in the work enivronment
Why do LCDs (Liquid Crystal Display) use less power than OLED (Organic Light Emitting Diodes) and Plasma display technologies?
*Because they use a technology that works by blocking light rather than emitting it.
Plasma display devices
*Contains a neon/xenon gas mixture sealed between two glass plates. *within the plates is a grid of cells in which the gas mixture is charged. *charged gas breaks down, produces ionized plasma. *emits UV radiation *The UV radiation activates color phosphors to produce red, green, or blue sub-pixels. *it's possible a plasma display to produce over 16 million different colors with a wide 160 degree viewing angle *free of distortion at edges of screen *better at displaying motion graphics without blur. *down side not as bright as other displays and consume more power
What causes display Artifacts?
*Crashed Pc, *check data cable connection *check overheating Graphic card *check for corrupt drivers
In-Plane Switching (IPS) liquid-crystal technologies LCD monitor
*Crystals are horizontally aligned with the screen rather than vertically as in the TN (Twisted Nematic) LCD. *The reason is this allows the polarized crystal to move more freely into the desired alignment . *IPS uses two transistors per pixel to improve the viewing angle over TN (Twisted Nematic). *Disadvantage: is this increase power consumption and decreases battery life in laptops and they have the slowest response time. *Advantage: is the best viewing angles of all LCP display technologies and ability to produce the most accurate colors.
Vertical Alignment liquid-crystal technologies LCD monitor
*Crystals are vertically aligned (producing black light blocks light) when there is no electrical current and horizontally aligned when there is current (producing white light allowing light to pass through producing a white image) *No twisting of the crystals *they are vertical/horizontal *Give an Advantage of high-contrast ratio - maximum brightness -Wide viewing angle -Good color production *Disadvantage: is it's response time is slower than TN (Twisted Nematic), and VA (Vertical Alignment) monitors are typically more expensive
What is the purpose of Backlit Technology?
*LCDs can be reflective or back-lit. *A light below a translucent reflector shines light toward the user making the display readable in low light situation. *Back-lit source can be LEDs, an electroluminescent Panel (ELP), or a variety of fluorescent light types.
What is Reflective Technology?
*LCDs can be reflective or back-lit. *A mirror in the rear bounces ambient light back to the user. *This technology is cheaper to implement *but in dimly lit rooms, reflective displays are difficult to impossible to read.
Brightness explained
*Measurement of the intensity of the energy output of a visible light source pure white having the maximum brightness and pure black the maximum brightness based on the amount of ambient light
Refresh rate explained
*Measures how often the display image is updated per second in hertz (Hz) *common display refresh rates are 60, 75, 85, and 100 Hz *The higher the refresh rate the less redrawn (flicker) there is. *The maximum refresh rate you can choose is also affected by the display's resolution. *800 x600 resolution supports higher refresh rates than higher resolutions 1600 x 1200.
What colors can Backlights come in?
*Monochrome LCDs might have yellow, green, blue, or white back-light, and color LCDs use white back-lights covering most of the color spectrum
What are the three main advantages LCD display projectors have DLP (Digital Light Processing) projectors?
*Moore accurate colors because of a clear section in to the DLP color wheel. *It boots brightness, but reduces color saturation. *Slightly sharper images than DLP at same resolution *Brighter image than DLP at same wattage lamp
Twisted Nematic (TN) liquid-crystal technologies LCD monitor
*Perpendicular orientation confined between two plates of polarized glass *Most common and oldest LCD *Advantage: -shortest response time -low power draw -high brightness when combined with LED back-lighting -inexpensive to manufacture *Disadvantage: -The colors distort as you view the screen from the side and from above *Commonly have a viewing angle of less than 100 degrees.
What are some advantages DLP (Digital Light Processing) projectors have over LCD display projectors ?
*Smaller and more portable because of the mirror chip instead of panel. *Produces deeper blacks and higher contrast. *Less pixilation allow smoother motion graphics *More reliable as there are few parts to break
Display Resolution (individual points of light or color)
*The displayable number of pixels, expressed as horizontal pixels and vertical pixels numbers, such as 1024 × 768, 1152 × 864, and 1280 × 1024. *Has to do with sharpness
name the OLED (Organic Light Emitting Diode) display four primary layers:
*The substrate *The anode *The cathode *The organic layer
If you are working in a room with high ambient light, which display setting would you adjust to be able to see the screen better?
Brightness
Analog or digital connection explained
If possible, use a digital connection, such as DVI HDMI DisplayPort
Display projectors have two display projectors technologies:
LCD Digital Light Processing (DLP)
Which display setting is not adjustable on LCD (Liquid Crystal Display) display?
Refresh rate, also called "native resolution"
If the colors on your monitor appear faded, muted, too dark, or too light, you can adjust the color depth using Windows Control Panel Display applet. TRUE or FALSE
TRUE
Native Resolution
The actual (and fixed) number of pixels built into an LCD monitor. For the clearest display, always set the resolution to the native resolution.
How do Laptops small circuit board (Screen inverter) that attach to the display screen work?
The inverter direct current from the MB and converts it into alternating current which is the * [electrical current] used to control the pixels and generate the images
What will happen if you select a refresh rate not supported by the display?
The screen will go blank/distort the image
What is the refresh rate controlled by?
The video card, however, the rate you choose must be supported by both the video card/display device.
What is Passive Matrix LCD?
This consists of a series of circuits that intersect one another. At each intersection, a single LCD element enables light to pass through or block it. This is an older technology. *Liquid crystals at that location twist or staighten
