The concept of interactive TV has been brought out as early as the establishment of cable TV. However, back then, the technology is not sophisticated enough to support the interactive TV to be commercialized. Following the advance of technology, the infrastructure for interactive TV distribution is complete that enables the broadcasting industry to experiment interactive TV in many major cities of the world. Traditional television is a one-to-many broadcast medium with passive viewers that is going to be overturned by the interactive TV which allows the viewer to interact with the television set in ways other than simply controlling the channel and the volume and handling videotapes.
The differences between the interactive TV and traditional television are listed as following:                (1) viewer participation: the interactive TV enables a viewer to comment a program while watching it and seeing the comment to be broadcasted in real time. For instance, a viewer of a ball game can vote to predict “which team is going to score next” and acknowledge to voting result instantly on the TV screen.        (2) personalized programming: the interactive TV provides a service of Video-on-demand enabling a viewer to watch any movie or program at any time convenient to him/her, by which the viewer can request a video and have it sent specifically to him/her, with VCR-like capabilities to pause, stop, rewind and fast-forward at any time, and furthermore, the viewer can save the selected videos on a central video server and play them at leisure by the playing order preferred thereby.        (3) information retrieval: a viewer can get information on everything he/she wants using interactive TV, for instance, a viewer can inquire local weather at any time, and further, the service allows quick tracking of stocks and sports teams that are of interest to the viewer, by providing customized details on stocks and teams of choosing.        (4) distance learning: interactive TV makes it possible for the whole family to educate themselves on all sorts of topics, in their own living room, at their own pace and in private. For instance, children can learn to read, see what Saturn looks like, and they will be able to see all the other students and the teacher at any moment in time in live transmissions but can learn whenever they preferred, and much more.        (5) home shopping: merchandises cataloged in an interactive TV system enable a viewer to order articles—ranging from supermarket items to clothes, and schedule to have them developed the following day, ordering it by pushing a single button on one's remote control, while sitting in your chair watching TV.        
By now it is realized that interactive TV is similar to PCs in certain aspects—both offer interactive services. It is uncertain if PCs can offer hundreds of entertainment channels like interactive TV, but PCs have processors which are more advanced than those in interactive TV, allowing it to create and run programs such as word processors, databases, spreadsheets and other application programs. Therefore, the combination of computers and digital TVs should be the trend of future development. However, the combination of computers and digital TVs also requires a combination of the two different kinds of user interface used on these two kinds of machines. Computers use keyboards and mice as input devices, but TVs use remote controls as input devices. An interactive TV requires an input device which is good both for a computer and for a TV. Thus, a good input device for interactive TV is a compact, artistic, and easy-to-use input device integrating remote control capability and the capability of manipulating a cursor position.
There are already some prior-art devices capable of being used as the input device of interactive TV. One of which is a multi-functional remote control disclosed in TW Appl. No. 81211827. The referring patent provides a easy-to-use and good-looking multi-functional remote control integrating the remote control capabilities of most common household electronic appliances, such as television, video recorder, air conditioner, fan, etc., that can be used for replacing the plural remote controls of such appliances.
Another prior-art input device is disclosed in TW Pat. No. 00538640, which is a handheld device with integrated functions of remote control and information accessing. In a preferred embodiment of the referring patent, the patented device is embedded in a handheld apparatus, such as cellular phone, PDA, and e-book, etc., for enabling the same to function as an interactive TV.
Moreover, a method for moving a displayed object on an interactive computer graphic display in response to one of pitch and yaw rotations of an input device is disclosed in U.S. Pat. No. 5,898,421, entitled “GYROSCOPIC POINTER AND METHOD”, which utilizes a gyroscope to detect rotations of hands holding the input device while converting the detected angular velocity into cursor movements. However, the competitiveness of the referring device is impaired by the expensive gyroscope, and thus limited the popularity of interactive TV.
In addition, one more such device is disclosed in U.S. Pat. No. 5,926,168, entitled “REMOTE POINTERS FOR INTERACTIVE TELEVISIONS”, which can remotely direct a cursor to move in a way similar to that of a light-gun. However, the movements of the cursor controlled by a light-gun appear to be an intermittent movement of single dot jumping around a television screen, that the intermittent movement is not applicable to most common applications, but only to shooting games. Therefore, the referring device has poor marketing potential, and thus limits the interactive TV to a specific small user group.
All the above mentioned input devices can perform the basic functions of an interactive TV, such as moving a cursor and clicking on an icon or manual. However, all these devices have one common disadvantage: the cursor position can not be controlled intuitively, comfortably or conveniently by the standard of average home users. It is therefore imperative to invent a new and better input device that provide the comfort and convenience.