Computer graphics processing and selective visual display system – Display peripheral interface input device – Cursor mark position control device
Reexamination Certificate
1999-02-24
2003-12-16
Chang, Kent (Department: 2673)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Cursor mark position control device
C345S157000
Reexamination Certificate
active
06664947
ABSTRACT:
BACKGROUND
1. Field of Invention
The proposed invention relates generally to hand controllers or computer display pointing devices such as mouses, joysticks, and trackballs. More specifically, it relates to ergonomically shaped pointing devices, which eliminate harmful stresses in wrist and hand joints thus providing substantially improved functionality and prevent computer related injuries.
2. Description of Prior Art
The use of pointing devices for entering signals into a computer is well known in the art. Moreover, there is a great variety of so-called ergonomically shaped devices for this purpose. The most widely known devices can be represented by examples. U.S. Pat. No. 3,835,464 to Rider (1974) discloses a hand-operated position indicator for computer controlled display system. A hemispherical housing provides a plurality of buttons and a sphere located on a bottom structure supported on the underlying structure.
Basic functions of different mouses are very similar and remain about the same for a long time. Some common problems in the use of mouses are well known in the art. After a protracted period of continuous use, there is a muscle fatigue in a forearm, soreness, and even pain in the hand. In recent years, a medical problem formerly described as wrist level median nerve entrapment, but now commonly referred to as carpal tunnel syndrome (CTS) has taken on an ever-increasing significance, particularly in monetary payoffs by states for worker's compensation claims and by insurance companies for claims related to CTS surgery. The decease usually can not be treated well without a complete stop of use of the injured hand. By a definition of the American National Institute of Health “CTS occurs when tendons in the wrist become inflamed after being aggravated. A tunnel of bones and ligaments in the wrist narrows, pinching nerves that reach the fingers. Symptoms range from a burning, tingling numbness in the fingers, especially the thumb and the fore-and middle fingers, to difficulty gripping or making a fist. Approximately one percent of individuals with carpal tunnel syndrome develops permanent injury. The majority recover completely and can avoid re-injury by changing the way they do repetitive movements, the frequency with which they do the movements, and the amount of time they rest between periods when they perform the movements.”
It is commonly believed that the cause of the decease is in that those pointing devices are not well shaped ergonomically to fit to the use's hand. Two common directions of improvements can be specified:
better accommodate pointing devices to the anatomical shape of a relaxed hand posture and to decrease bending of the forearm-wrist joint;
decrease a probability of inadvertent activation (pushing, clicking) of the control keys generating computer commands.
There are many patents issued for ergonomically shaped pointing devices improving their shape in a number of ways. U.S. Pat. No. 4,862,165 to Gart (1989) proposes an anatomical shape to fit the hand perfectly in order to avoid hand fatigue and discomfort after even a protracted period of use. This mouse is shaped so as to support the elevated palming position, support a thumb, support middle, ring, and small fingers in a relaxed wrapped position. However, the main operating forefinger is in a stretched and consequently stressed position above the push button. The user's forefinger can not relax unattended to avoid activation of a button. This is the main reason of static stress, because this mouse has no protection from unintentional activation.
U.S. Pat. No. 5,576,733 to Lo (1996) teaches that a conventional mouse requires constant muscular force to be applied to the hand, wrist, and forearm to maintain their positions twisted from neutral posture. For a three-button mouse, the fore-, middle, and ring fingers must be kept in constant tension to prevent them from resting too heavily on the buttons and depressing them inadvertently. Lo teaches that the hand is about 80-90 degree twisted left from the normal upright position with a conventional mouse. Lo supposes that the best-relaxed position of the hand on the pointing device must be vertical upright keeping the fingers in a stack position to eliminate twisting of the hand.
However, the fingers controlling the buttons are all straightened, hence, contradicting the idea of the wrapped fingers typical for a relaxed hand. Moreover, the vertical upright position is optimal for only a hand, which elbow is very close to the user's body. It is not so relaxed, when the elbow is distant from the body as in a usual situation, when the computer keyboard is in front of a user. It is easy to understand imaging a pistol grip in hand: when the elbow is squeezed to the body, then the grip is about vertical. When the elbow moved away from the body, the grip becomes substantially horizontal. Consequently, the hand on a mouse must not be turned upright too much to be vertical: it is not anatomical and, hence, limits the hand functionality. It is especially true, when the hand is operating a mouse at the desktop edge. Besides, this mouse substantially limits finger functionality.
U.S. Pat. No. 5,355,147 to Lear (1994) proposes a vertical mouse structure with a palm-wrist support. The activator switches or push-buttons are designed to be pressed by the thumb and the bent fingers wrapping a vertical grip. This mouse provides as good functionality for the fingers as any other pointing device of the type known as joystick. It is also protected from unintentional button activation in the same way as other joystick-type pointing devices. However, this device is cumbersome in comparison with conventional mouses and does not provide a possibility of using the wrist and finger functionality for fine positioning. Besides, it is rather difficult for computer users to change usual function of the middle finger to the thumb.
One more example is a well-known highly operable pistol grip. It provides at least two important functions simultaneously: a firm grip and a gentle relaxed position for the operating forefinger pulling a trigger. Pistol grips are very functional in both senses. Such grips used to be optimal for vertical controllers. They are widely used as vertical joystick devices. Such kind of grips is substantially protected from unintentional activation. In a vertical grip, the axis of rotation/bending of the forefinger is vertical. The finger can be kept standby in this position as long as needed without any power applied. Hence, there is no specific stress in the hand, which is typical for all horizontally operating mouses.
U.S. Pat. No. 5,296,871 to Paley (1994) claims a three-dimensional mouse operating in free space. This pointing device is designed essentially as a pistol grip including a thumb push button, a forefinger push button, and a grip push button. Paley has mentioned that such grips are substantially free from a danger of unintentional activation. Consequently, they can be recognized as safe grips: they don't induce the static tension in a hand and a stress in the user's brain from the necessity to continuously control the command fingers. On the other hand, these grips are safe, because they are essentially protected from generating erroneous command. That is why such grips are widely used in mission critical applications including weapon control. However, they need some constant efforts to just be held in hands.
Unfortunately, pointing devices of this kind is difficult to use on a desktop surface in comparison with conventional mouses. That is why the ergonomic mouse by Gart is not safe and has the same drawback as other conventional mouses. It was shaped essentially similar in some respect to an orthopedic pistol grip and adapted for use on a horizontal surface. That is the operating forefinger pulling the pistol trigger bends in horizontal but not in vertical plane. While it is in relaxed position in a pistol grip, it can not be relaxed with such grip in horizontal position to avoid an inadvertent action onto the u
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