Laptops – What’s on your Screen?
The whole idea of a laptop (aka notebook) is to make all your digital files accessible 24/7 in a portable environment sans cables and cords. Plus, advances in WiFi have allowed college students and travelers alike the ability to browse the internet and check e-mail while in the classroom or reviewing a presentation on a redeye flight for an early morning meeting. But, what good is all that data if poor screen quality makes it difficult to read your number-crunching spreadsheet?
Laptop screens took a large step forward when they went from Passive Matrix to Active Matrix screens. The result was brighter and sharper images plus quicker response times. The screen is probably the most advanced part of your laptop and was flat panel before flat panels were cool. Active Matrix screens are perfectly flat (corner-to-corner) and are just a half-inch thick.
LIQUID CRYSTAL DISPLAY (LCD)
Yes, there really is a liquid crystal layer in the center of your LCD display inside your laptop. But how can something be liquid (fluid) and crystal (solid) at the same time? Liquid crystals are neither a liquid nor a solid but they are closer to a liquid state than a solid.
Why are liquid crystals used in LCD screens? They have molecules that align collectively along a certain direction. This collection of liquid crystals can be manipulated by magnetic influences and electrical charges. The controlled voltage application causes the liquid crystal to perform image displaying properties utilizing an electro-optic effect of the liquid crystal. Plus, they are very thin; usually restricted to 5-25 micrometers. To give you an idea of how thin the liquid crystal layer is, five micrometers is just .0001968503937007874 of an inch.
Liquid crystals are sensitive to temperature extremes at both ends of the spectrum. That’s why your laptop might act funny after sitting in your hot car or perform sluggish during exposure to cold weather. The liquid crystal layer will get too fluid during hot weather and too solid during cold weather. The screen of your laptop is actually several different panels sandwiched together.
SCREEN SIZE & RESOLUTION
For most things in America, bigger is better. But, you don’t want a screen so large you can’t place it on your flight’s tray table or actually place your laptop on … gasp, your lap. In fact, most card-carrying frequent fliers will balk at a giant desktop replacement laptop and will opt for a qualified carry-on-luggage sized screen as small as a 12 or 13-inches.
Similar to televisions, your laptop’s screen dimensions are measured diagonally, not by width. For example, the following 17-inch laptop screen measures 14.4-inches in width.
The following table shows the relationship between screen size (measured diagonally), screen resolution width and height (measured in pixels), whether the screen resolution is standard or widescreen, pixel pitch measured in pixels per inch (PPI), the aspect ratio of the screen, and the total amount of viewable megapixels on the screen.
A comparison of the four widescreens listed above.
WHAT IS BACKLIGHTING?
Let’s debunk a common misconception – laptops have either an LCD screen or an LED screen. No. All laptops have LCD screens which are backlit in two different manners; CCFL and LED. Until recently, the LCD screen on your laptop had only one option to provide the brightness and contrast – the backlighting obtained from cold-cathode fluorescent lighting (CCFL). The industry is seeing more and more LCD laptops screen being backlit with LEDs.
The glass tube contains mercury vapors which are under low pressure. When the mercury vapor becomes electrically charged (ionized), they emit ultraviolet light (which humans cannot see). The inside of the fluorescent tube that contains the mercury vapors is coated with phosphor, which is a luminescent substance. The phosphor accepts the energy from the ionized mercury vapors and then emits that new energy in the form of visible light.
The fluorescent tubes are built into the chassis of the laptop and are located above and beside the LCD screen. On some laptops, they can be found behind the LCD. To ensure a uniform distribution of the white light created by the fluorescent tubes, a white diffusion panel mounted behind the LCD redirects and scatters the light evenly.
Although CCFL is still the most common form used to backlight your LCD screen, LED backlighting is being seen more and more because of two major advantages – battery life and no mercury. To compare the average battery life power consumption of a 12 to 14-inch CCFL backlit to LED backlit widescreen laptops, the LED uses one to two fewer watts. To translate watts to battery life, that’s an extra 30-45 minutes per watt of working on homework or browsing the internet waiting for your flight to board.
Neither CCFLs nor LEDs produce heat very far above the ambient temperature inside the laptop. This makes both forms of backlighting ideal for LCD screens due to the close proximity to the internal components that can be damaged or ruined by the additional heat provided by the CCFL lamps and LEDs.
And if you thought laptops couldn’t get any thinner, think again. LED backlighting will allow laptops to not only become skinnier, but lighter. This is an added bonus to the additional battery life.
MATTE vs. GLOSSY
No, we’re not talking about the finish on your family photos; we are talking about the viewable area on your laptop. You have two types to choose from: matte or glossy.
Glossy screens are the more popular choice and have a coating applied to the screen that is reflective. The original glossy screens were distracting because they mirrored just about everything in your surroundings onto your screen. The advancement of high-gloss, but anti-reflective screens was so big, that most manufacturers have coined a moniker for their invention.
- HP/Compaq = BrightView
- Sony = XBRITE
- Toshiba = TruBright
Another upside to glossy is the reduction of the screen door effect which is caused by the black spaces between pixels. Plus, glossy improves the brightness and contrast of the images displayed on the screen.
All LCD screens have a thin sheet of film laminated to the outside layer of the glass known as a polarizer. The difference between anti-glare (traditional notebook screen) and an anti-reflective laptop screen is the type of polarizer film used in manufacturing. Basically, it is a matter of choice but with the technologies for glossy reducing the mirror-like reflections, matte might be on its way out entirely.
FINAL THOUGHTS
Shopping for a laptop is a little different than purchasing a desktop. Screen size is very important. You can find a 12-inch model which would be perfect for the traveler and screens up to 20″ that act as a desktop replacement.
If battery life is extra important in your purchase, consider an LED backlit screen that won’t be such a drag on your battery. Not to mention the environmental benefits of not having mercury in your computer. And if you’re using your glossy screen as a mirror to get dressed in the morning, it is time to find an anti-reflective model.
Still have questions? – feel free to speak with an hhgregg associate. We offer the best-educated associates in the business who are smart enough to make it simple. Price and Advice Guaranteed!
