Computer graphics processing and selective visual display system – Display peripheral interface input device – Cursor mark position control device
Patent
1996-08-13
1999-09-28
Swarthout, Brent A.
Computer graphics processing and selective visual display system
Display peripheral interface input device
Cursor mark position control device
345145, 345168, G09G 508
Patent
active
059596120
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to computer pointing devices, in particular to such devices as used in portable computers.
2. Background and Prior Art
The presently used pointing devices like the mouse, the joystick or trackball use mechanical moving parts to translate the operator's hand movements into the movements of the computer cursor. However, in small and portable computers, like laptop computers, the space on the keyboard is inadequate for mounting of such devices which are of dimensions suitable for easy and unrestrained actuation. During operation, the operator's hand often covers the keyboard or an essential part of it and the pointing device is too small compared to the hand to precisely control the movement. In computers and control panels designed for operation under adverse conditions (water, dust, body liquids, etc.) it may be bard to make the system tight and protected. Other solutions include pointing devices to be used at the screen, like the light pen. Such a device has the disadvantage of being a separate additional device, sometimes hard to use on a tilted screen. Yet other pointing devices, such as digitizers, have been invented and are in use in precision digitalization. These include acoustic tablets, where two orthogonal microphones detect the relative position of a sound source (e.g. an electrical discharge at the tip of a pen-like device) based on the time elapsed for the sound to reach the respective microphones. In all cases known to us, the pointing device is movable or separate device, often requiring the possibility and space to lean the hand and arm against a fixed object in order to closely control the movements of the hand controlling the pointing device.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide for a computer pointing device which enables the control of the cursor movements by activation of a device containing no moving parts and thus overcome the problems of the present small or separate pointing device actuators mentioned above. The pointing or control device shall be compact and protected from impairement by water, dust, body liquids etc. within a housing.
The invention is characterized by the features of claim 1. Advantageous embodiments of the invention are described in the remaining claims.
The apparatus according to the invention enables the control of the cursor movements by activation of devices without moving parts and thus overcomes the problems of the present small pointing device actuators in the following way:
The movement of the object may be detected and conveyed to the computer memory by an optical movement detection device at the bottom of a recess on the computer housing or by a set of ultrasonic transceivers at the same place. These devices may be mounted onto a protrusion from the computer housing as well. In both cases the detectors use waves (mechanical or electromagnetic) to detect the movement of, for example, the operator's hand in front of the device as illustrated in FIG. 1.
The optical system contains light transmitters and receivers that can detect movements of objects moving in front of them. This detection is designed in such a way as to particularly detect the movement of the operator's palm leaned against the recess. The transmitter's and the receiver's directivity characteristics are focused and intersect at the level of the palm surface as the palm is moved in front of the recess. The transmitter-receiver sets are arranged orthogonally so that each of the sets can detect one (Cartesian) coordinate of the movement. Other angular arrangements have a lower sensitivity. The movement detection is done by the calculation of the cross correlation of the detected light levels at pairs of light receivers which are a known distance apart and detection of the time delay corresponding to the speed of the object passing in front of the detectors. The crosscorelation function has an extreme at the delay which corresponds to the time needed for the two light reflect
REFERENCES:
patent: 5059959 (1991-10-01), Barry
patent: 5168531 (1992-12-01), Sigel
Breyer Branko
Ferek-Petric Bozidar
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