Your iPod, iPhone and tablet are commonly known to have three key components: a glass panel, digitizer (aka touch screen) and LCD. What are the differences? Let’s clearly define these layers:
- Layer #1: Glass panel – the topmost layer
- Layer #2: Digitizer (also known as touch screen) – just under the glass and fused with it
- Layer #3: LCD – located under the digitizer
Glass – The outermost layer is the glass, typically less than one millimeter thick. If you drop your device, the cracked glass ends up resembling an elaborate spiderweb.
Digitizer – The digitizer is located just under the glass screen. It is the electrical force that senses and responds to touch. When you tap your fingertip or swipe it across the screen, the mere touch acts as data input to the device’s center. If your device fails to respond to touch, it’s time for a new digitizer. The digitizer is an electrical mechanism that is fused with the glass screen; so if you need to replace the digitizer, you’ll have to replace the glass, too, and vice versa. UEG offers a Front Glass (Digitizer Touch Screen) Repair Service on tablets.
Touch Screen – The term touch screen is interchangeable with the term digitizer. You’ll often see the combined terms Digitizer Touch Screen offered as a repair service.
LCD – LCD is an acronym for liquid crystal display. The LCD is the visual component underneath the glass that displays the image on the screen. UEG offers LCD repairs on tablets, iPhones and iPods.
THE DIFFERENCE BETWEEN THE TOUCHSCREEN AND AN LCD SCREEN
A touchscreen is an electronic input device that the user can control with single or multi-touch gestures. The touchscreen enables the user to interact directly with what is being displayed, rather than using a mouse, touchpad, or any other intermediate device.
Some touchscreens can be controlled by fingers; others may require the use of gloves with a particular type of coating, or the use of a special stylus pen.
The touchscreen prototype was developed in 1977 by Ben Stumpe, a Danish electronics engineer. Multi-touch technology development began in 1982, when the University of Toronto’s Input Research Group introduced the first human-input multi-touch system. It was using a glass panel with a camera placed behind the glass. Later, in 1985, the University of Toronto group including Bill Buxton developed a multi-touch tablet that used capacitance rather than bulky camera-based optical sensing systems.
Nowadays, touchscreen devices have established themselves as an industry standard for most smartphones, tablets and a large fraction of laptops. Most households will have at least one device with a touchscreen, and our customers are no exception.
As a result of the wide popularity, these screens brake on an occasion. What many users fail to take into the consideration, is that the touchscreen and the actual LCD screen are two independent parts.
So:
Touchscreen (AKA digitizer) is the thin transparent layer of plastic, which reads the signal from the touch and transports it to the processing unit. It is the part that you can touch without disassembling the device.
LCD screen is the panel that is inside the device, which displays the image. You can not get to the LCD without taking the device apart first.
When only the touch screen is broken, you should still see what is happening on the screen, and the screen should still function as normal.
When only the LCD is broken, you can still use the touchscreen, but the panel will have dark blobs or spiderweb-looking cracks (or both).
When both LCD and touchscreen are damaged, you may still be able to use portions of the touchscreen, and some parts of the LCD may display the image, but you will incur obvious difficulties in using the device as normal.
What Is a Touch-Screen Digitizer?
Although modern PCs are tied to their keyboards, touch-screen technology takes the place of a keyboard and mouse for smartphones and a host of other devices. To sense the position of your fingertips, the touch screen employs a digitizer, a component that turns the screen into a set of coordinates on a grid. The digitizer tracks the movement of your fingers in real time, to control actions such as tapping out a text message, shooting a target in a game or bringing up the latest weather report.
Form and Location
Typically, a touch-screen digitizer is one piece in a multilayered "sandwich." In modern devices, the screen that produces the images is found at the bottom layer; the digitizer is a transparent sheet that occupies a middle layer on top of the screen, and a thin sheet of hard, protective glass forms the top layer.
Action
The digitizer layer contains a set of microscopically small sensors arranged in regular rows and columns all over its surface. Touching the screen triggers sensors immediately under your fingertip; a specialized electronic circuit receives signals from these sensors and converts them into a specific location on the screen as X and Y coordinates. The circuit sends the location to software that interprets the touch and location according to the app you're using. For example, when you dial a phone number, your fingers touch the numbers on a virtual keypad on the phone's screen. The software compares the locations touched against the keypad and generates a phone number one digit at a time.
Touch-Screen Devices
Devices that use touch-screen technology include smartphones and tablet computers. Because they don't require a dedicated keyboard, the usable screen size is maximized without compromising any capabilities. Graphics tablets used by artists and industrial designers also employ digitizers, as do ATMs and information kiosks. Because traditional keyboards and mice can be vulnerable in dusty or dirty environments, some industrial machines use touch screens for monitoring and control.
Multitouch
In recent years, an improved digitizer system called multitouch has brought more convenience to smartphones and other mobile devices. Multitouch tracks two or more fingers on the screen at the same time, allowing sophisticated gestures such as shrinking a picture by pinching it.
How the Digitizer / Touch Screen Works
There are two layers of glass for the digitizer assembly. The first is simply glass, which is what you touch. The second is attached to the glass and senses the touch via an electrical field which transmits and receives based on the "return" from your finger or stylus. The digitizer and LCD work independently from one another. So if one fails, it won’t necessarily cause the other part to fail. With cracked glass, you can see the content on your screen, but there is broken glass which makes it hard to see. Cracks, splinters, and shattered glass can be present while the digitizer is still responsive. However, the digitizer can fail over time.
Preventive measures include using a case for your phone that creates separation between objects and the screen. Cases that don´t create a ridge on the glass side of the screen may be fashionable, but they don't protect the glass. And screen protectors will only prevent scratches.
Digitizer (Touchscreen) Failure is when a phone stops responding to touchscreen commands. This can occur with impact damage (usually associated with cracks in the glass), extreme heat (such as lying in the sun for extended periods of time) or water damage to the device.
Remember that glass can scratch from a variety of things, including keys and rough surfaces such as concrete or pavement. Glass can be replaced to make your cell phone look new again. But try not to drop your phone!
Use a screen protector to prevent any kind of damages, but remember a hard case is always better. It's always cheaper to buy a case than having to replace or repair your device.