What is Tablet PC?
Computers powered by the Windows XP Tablet PC Edition operating system, and equipped with a sensitive screen designed to interact with a complementary pen, are called Tablet PCs. Tablet PCs are fully-functional laptop PCs and more. You can use the pen directly on the screen just as you would a mouse to do things like select, drag, and open files; or in place of a keyboard to handwrite notes and communication. Unlike a touch screen, the Tablet PC screen only receives information from a special pen. It will not take information from your finger or your shirt sleeve—so you can rest your wrist on the screen and write naturally. By interacting directly with the screen, rather than with a mouse and keyboard, the PC becomes more comfortable and easy to use. There is no need to find a flat space on which to use your PC, nor does a vertical screen become a dividing wall between you and the person with you whom you are meeting. What's more, a Tablet PC can even be used while standing up, which is perfect for professionals on the move such as doctors, foremen, and sales managers.
Windows XP Tablet PC Edition 2005 includes all of the features and functionality of Windows XP Professional and Windows XP Service Pack 2. Tablet PCs do not run Windows CE or Windows XP Embedded.
A number of manufacturers produce Tablet PC models that differ in size, processing speed, design, etc. to meet anyone's need. Three different styles of Tablet PCs are available:
The convertible model Tablet PC has an attached keyboard and looks much like a conventional laptop PC. But you can also rotate the screen 180 degrees and lay it flat over the keyboard for a more comfortable reading and writing experience.
The slate model Tablet PC is designed to be slim and ultra-light without the weight and size of a permanent keyboard. Some models come with a detachable keyboard, and all include innovative docking solutions that offer access to a full-size monitor, keyboard, and mouse.
The rugged model Tablet PC is a tough mobile computer with an industrial-strength shell and shock-mounted hard drive. Rugged models are ideal for people who use their PC in a construction zone, while on patrol, in military situations, or simply for those who need something ultra durable.
Along with the options typically provided by a conventional laptop, Tablet PCs are certain to include:
| • | Mid- to high-end processors that are optimized for mobile computing |
| • | High memory capacity for most computing needs |
| • | High capacity hard drive storage space |
| • | Built-in 802.11b and/or 802.11g modem for wireless and networking connectivity |
| • | Tablet PC-compatible electronic pen |
| • | Tablet PC-compatible digitizer screen |
A Tablet PC is a notebook or slate-shaped mobile computer, first introduced by Pen Computing in the early 90s with their PenGo Tablet Computer and popularized by Microsoft. Its touchscreen or graphics tablet/screen hybrid technology allows the user to operate the computer with a stylus or digital pen, or a fingertip, instead of a keyboard or mouse.
The form factor offers a more mobile way to interact with a computer. Tablet PCs are often used where normal notebooks are impractical or unwieldy, or do not provide the needed functionality.
The Tablet PC is a culmination of advances in shrinking notebook hardware and improvements in integrated digitizers as methods of input. A digitizer is typically integrated with the screen, and correlates physical touch or digital pen interaction on the screen with the virtual information portrayed on it. A tablet's digitizer is an absolute pointing device rather than a relative pointing device like a mouse or touchpad. A target can be virtually interacted with directly at the point it appears on the screen.
Inputting data
Tablet PCs using Windows XP Tablet PC Edition or Windows Vista may utilize the Ink object as a means of data input and storage. This is a data type first created as part of the Windows XP Tablet PC Edition API that allows one to manipulate and process handwritten data, including recognition results and, in some cases, the pressure information for each part of the stroke. Properties of Ink can be changed in much the same way as properties of other objects, and the data can be saved to allow future reference. Many applications referencing the Ink object also allow handwritten notes to be filtered and searched through, based on the recognition results stored when Ink is saved.
A popular use of the Tablet PC form factor is to enable computerized manipulation, organization, and reading of large amounts of printed information. In particular, casual readers may download electronic versions of their favorite books to read on their Tablet PCs, or students may scan in the pages of textbooks and just bring their Tablet PCs to class in lieu of bulky textbooks. Universities have begun integrating Tablet PCs with shared resources such as
whiteboards, where students and teachers can interactively manipulate the same images.
Inputting data
Tablet PCs using Windows XP Tablet PC Edition or Windows Vista may utilize the Ink object as a means of data input and storage. This is a data type first created as part of the Windows XP Tablet PC Edition API that allows one to manipulate and process handwritten data, including recognition results and, in some cases, the pressure information for each part of the stroke. Properties of Ink can be changed in much the same way as properties of other objects, and the data can be saved to allow future reference. Many applications referencing the Ink object also allow handwritten notes to be filtered and searched through, based on the recognition results stored when Ink is saved.
A popular use of the Tablet PC form factor is to enable computerized manipulation, organization, and reading of large amounts of printed information. In particular, casual readers may download electronic versions of their favorite books to read on their Tablet PCs, or students may scan in the pages of textbooks and just bring their Tablet PCs to class in lieu of bulky textbooks. Universities have begun integrating Tablet PCs with shared resources such as whiteboards, where students and teachers can interactively manipulate the same images.
Handwriting recognition
Modern day processors and advances in recognition algorithms make the conversion from handwriting to text far more practical now than it was in early attempts of Tablet PCs.
Current handwriting recognition technology employed by Tablet PCs are effective at recognition of natural cursive writing, rather than letter-by-letter recognition. Letters in the context of words are recognized for finding possible sequences within an input block of handwriting. The sequences are then compared to a dictionary of words for determining the most likely sequence, with a list of alternatives presented to the user. On known (in-dictionary) words, this method is more accurate than letter recognition, however modern system also address recognition of out-of-dictionary words, notably email and web addresses, new slang terms, proper names, and domain-specific terminology. Handwriting recognition software often presents a letter recognizer option to better enable precise input.
Handwriting recognition in Windows
The integrated handwriting recognition in Windows XP Tablet PC Edition 2005 can recognize print, cursive, or mixed writing. Accuracy can be increased by configuring the recognizer to expect left-handed writing or right-handed writing. Recognition in a variety of languages is available by installing a recognizer pack. The handwriting engine cannot be trained in Windows XP, forcing the user to retrain their handwriting to be better recognized by the system.
The integrated handwriting recognition in Windows Vista is, however, trainable in a variety of ways. Vista offers the option for users to correct specific errors in recognition, provide samples for a set of common characters, or to provide a large set of handwriting samples directly on the computer. There is also the option to use automatic learning - this feature pays attention to things like which words the user includes in emails, and which recognition results they correct. It automatically adds those words to the dictionary and/or increases the likelihood of those words being recognized for improved recognition in the future.
Tablet PC Input Panel
The original Tablet PC Input Panel (TIP) included a handwriting panel, an on-screen keyboard, and a write anywhere function which allowed the user to literally write anywhere on the screen, after which the recognized data would then be sent to the currently focused input box.
The enhanced TIP introduced in the Service Pack 2 update (Windows XP Tablet PC Edition 2005) includes improved handwriting recognition, the option to correct a recognition error before it is sent to an application, and integrates the option to manually add a word to the computer's dictionary to improve its recognition in the future. The TIP can also add inline correction functionality to applications that support Advanced Text Input Services. This works by the TIP temporarily storing the recognition results from data that it inputs into the application. This version of the TIP removed the write anywhere function in favor of a floating interface. In applications which used certain supported text controls, an icon would appear when the pen was in proximity to the screen. Tapping or hovering over this icon would open the floating TIP, which would expand horizontally and vertically as needed when the user wrote to the edge of the window. For applications which could not pop up the floating TIP, the docked state was still supported, in which the TIP would stick to the top or bottom of the screen, moving all other windows out of the way (expanding downward if docked at the top).
Types of digitizers
Active digitizer
An active digitizer, used in most tablet PCs, can track the position of the pen when it is in proximity to the digitizer. This feature allows the user to "hover" over items on the screen. This can provide helpful functionality such as the ability to view tooltips and auto-hidden items, and to navigate through menus without accidentally activating an item.
Active digitizers can be installed behind the screen, allowing for maximum visibility, and most manufacturers install protectors over the screen to decrease the risk of damage to the LCD.
By using an active digitizer, the user's hand may rest on the screen without affecting the image or mouse pointer; only movement of the stylus affects the mouse pointer.
The most widely used digitizer, a Wacom digitizer, projects electromagnetic signals that are returned by the tablet's pen. The computer then calculates the position of the stylus based on the point in the electromagnetic field the stylus interacts with. Electronic switches inside the pen can also be sensed by the tablet.
UC Logic, Finepoint and N-Trig make other digitizers used in a few tablet PCs. Models incorporating these digitizers suffer from the lack of support in many graphics applications.
Averatec's C3500 line uses UC Logic digitizers. Compaq's TC1000 and Gateway's early convertible notebook series use Finepoint digitizers.
Finepoint's digitizer technology incorporates a battery-powered pen which actively transmits RF signals to be received by the tablet sensor. This results in lower power usage of the tablet PC itself, but greater size and weight of the pen because of the battery. The main advantage is that the accuracy problems related to interference from metal at the edge of the screen is not an issue.
Early revisions of Finepoint's digitizer, used in Compaq's TC1000, specifically suffered from the use of obscure, non-rechargeable AAAA batteries to power the pen, and did not support pressure sensitivity.
Older Gateway Convertible Notebooks (CX200/210, CX2600/2700, etc.) use Finepoint MP-800 digitizers. The batteries inside these pens are recharged by an inductance coil while the pen is stored in its compartment. Concerns over the reliability of the pen are the main problem with these models. Current Gateway models (C-140X and C-120X) use Wacom digitizers.
As on Jan 16 2008, HP's tx2000 is one tablet your writer is aware of which comes with active digitizer, which makes it easier to use programs like Ink Art. Earlier model tx1000 use the resistive passive digitizer, which is not pressure sensitive.
Passive digitizer
A passive digitizer, used in a touchscreen based tablet PC, only knows where the position of the finger is when the user presses down on it. This causes the pointer on the screen to jump to the location of the press and instantly "click". Passive digitizers are either capacitive or resistive.
The capacitive touch screen panel is coated with a material that stores electrical charges. When the panel is touched, a small amount of charge is drawn from the point of contact (the finger). Circuits located at each corner of the panel measure the charge and send the information to the controller for processing. Capacitive touch screen panels must be touched with an unprotected finger, unlike resistive, that can be operated by gloved hands or stylus.
The resistive touchscreen panel is coated with a thin metallic electrically conductive and resistive layer that causes change in the electrical current which is registered as a touch event and sent to the controller for processing. The resistive touchscreen panel can be operated by fingertip, stylus or gloved hand and does not need direct skin contact in order to operate.
Hybrid digitizer
Windows Vista adds formal support for hybrid digitizers including the ability of applications to distinguish between pen and touch input, as well as ability to turn touch input on or off.
More recently, tablet PCs have been equipped with hybrid digitizers that respond to both active pen and passive touch input. This allows the user to utilize simple finger based navigation, as well as the precision of pen input. An example of a tablet PC equipped with a hybrid digitizer is the Lenovo X60 Tablet with MultiTouch
In June 2007, TabletKiosk began shipping the Sahara Slate PC i440D, the first dual mode Slate PC with a hybrid display.
Stroking pen
The stroking pen is a combination of a regular ballpoint pen and a digitizer. While writing on a piece of paper that roughly fits onto the graphics tablet (or tablet PC) an exact digital copy is produced (as long as the paper stays in position). The advantages of this device are: a more natural writing experience, longer battery life of the tablet PC (because the display brightness can be turned down without limiting the visibility) and a spare (exact) paper copy for moments when it is needed (e.g., exams or loss of data on the tablet).
Tablets vs. traditional notebooks
The advantages and disadvantages of tablet PCs are highly subjective measures. What appeals to one user may be exactly what disappoints another. The following are commonly cited opinions of the tablet PC platform:
- More natural form of input — sketching and handwriting are a much more familiar form of input than a keyboard and mouse, especially for people who are new to computers.
- Gesture recognition — gestures (moving the stylus in special patterns over the screen) are powerful ways to increase efficiency. Many applications, or the operating system itself, can be programmed to respond in different ways to certain gestures created by the pen.
- Note-taking — taking handwritten notes and drawing diagrams at a class or conference increases productivity and retention of information. The notes can also be searched automatically if handwriting recognition is implemented.
- Accessibility — those who are physically unable to type can utilize the additional features of a tablet PC to be able to interact with the electronic world.
- Digital art — tablets are often necessary for professional digital artist work. For many, mouse movement is too jerky to be used as a precision tool.
- Portability — slate tablets and hybrids without keyboards are very slim and light compared to typical laptops and can easily be tucked under the arm like a book.
- Horizontal orientation — most tablet PCs do not interrupt line of sight since they lie flat on the table or in one's arms. This allows for better interaction in business meetings and conferences and also makes it easy for digital artists who wish to draw on a horizontal medium.
Disadvantages
- Higher cost — convertible tablet PCs cost roughly $300 more than their non-tablet counterparts as of 2005. This premium is expected to fall to as low as $75 by 2007. However, some models are intentionally priced at the same point or lower than equivalent notebooks without tablet functionality.
- Screen size — the size of tablet PC screens currently peaks at 14.1 inches. However, some models make up for this with very high resolution (a higher pixel density per unit area).
- Input speed — maximum handwriting speed can be significantly slower than maximum typing speed, which can be as high as 50-150 WPM.
- Screen damage risk - Because Tablet PC's are handled more than conventional laptops yet built on the frames of conventional notebooks, and because their screens also serve as input devices, many Tablet PC's run a higher risk of screen damage. PDAs carry some of the same risk.
- No built in optical drive (some Tablet PCs) — due to need for low mass
Slates
Slates, which resemble writing slates, are tablet PCs without a dedicated keyboard. Keyboards can usually be attached via a wireless or USB connection.
These tablet PCs typically incorporate small (8.4-14.1 inches/21–36 cm) LCD screens and have been popular for quite some time in vertical markets such as health care, education, and field work.
Slate models are often designed with a focus on pure mobility, that is, the less to carry, the better.
Rugged tablet PC models are usually in the slate form factor, because without a keyboard, there are fewer moving parts to break.
Thin-client slates
Thin-client slates consist of a touchscreen and an integrated wireless connection device. These units by design have limited processing power which is chiefly involved with Input/Output data processing such as video display, network communications, audio encoding/decoding, and input capture (touchscreen input, bar code reading, magnetic stripe reading (credit card swipe). The unit transmits data via a secured wireless connection to a remote server for processing.
Thin-client slates have the design advantages of a very lightweight form factor, more secure data (no data storage on the slate computer), long battery life (no processor to power). The Panasonic Toughbook 08 is representative of the application of thin-client computing to tablet PCs.
Convertibles
Convertible notebooks have a base body with an attached keyboard. They more closely resemble modern notebooks/laptops, and are usually heavier and larger than slates.
Typically, the base of a convertible attaches to the display at a single joint called a swivel hinge or rotating hinge. The joint allows the screen to rotate around 180° and fold down on top of the keyboard to provide a flat writing surface. This design, although the most common, creates a physical point of weakness on the notebook.
Some manufacturers, however, have attempted to overcome these weak points. The Panasonic Toughbook 19, for example, is advertised as a more durable convertible notebook. One model by Acer has a sliding design in which the screen slides up from the slate-like position and locks into place to provide the laptop mode.
Convertibles are by far the most popular form factor of tablet PCs, because for people who are unsure about the practicality of using the pen as the primary method of input, the convertibles still offer the keyboard and pointing device of traditional notebooks as a backup plan.
Hybrids
Hybrids, coined by users of the HP/Compaq TC1000 and TC1100 series (depicted to the right), share the features of the slate and convertible by using a detachable keyboard which operates in a similar fashion to a convertible when attached.
This is not to be confused with slate models that have a detachable keyboard—detachable keyboards for pure slate models do not rotate around to allow the tablet to rest on it like a convertible.
Despite a loyal following of users, the hybrid form factor has not received any recent updates after the TC1100 was discontinued.
No comments:
Post a Comment