Optical mouse

Abstract: An optical translator device capable of providing information indicative of the amount and direction of relative movement between the device and a surface positioned relative thereto. The device comprises a light source for providing at least partially coherent radiation and the source radiation is directed toward an area of the surface area. The reflected coherent radiation or light at the surface area undergoes optical interference due to the texture of the surface thereby forming a speckle pattern consisting of light and dark features. A detector array at the device comprises a plurality of photodetector cells and positioned in the path to receive the reflected light and to detect the light and dark features as represented by the cells in the array detecting light features in the reflected light thereby representative of a sample of the speckle pattern. Means is provided to compare consecutively produced samples which are indicative of the translatory information. A particular application of the optical translator device is a novel optical cursor control device which derives its translatory information from movement on substantially any sufficiently reflective surface. The output of the detector array is provided to circuit means to produce signals indicative of the amount and direction of relative cursor control device movement over the surface based upon observation of changes and movement of the speckle pattern as presented to the detector array. Such a device can be characterized as a "padless optical mouse" to provide orthogonal signals to move a cursor from position to position on a display screen in response to movement of the mouse over any sufficiently reflective surface, such as a desk top.

Abstract: An optical mouse images as an array of pixels the spatial features of generally any micro textured or micro detailed work surface below the mouse. The photo detector responses are digitized and stored as a frame into memory. Motion produces successive frames of translated patterns of pixel information, which are compared by autocorrelation to ascertain the direction and amount of movement. A hold feature suspends the production of movement signals to the computer, allowing the mouse to be physically relocated on the work surface without disturbing the position on the screen of the pointer. This may be needed if the operator runs out of room to physically move the mouse further, but the screen pointer still needs to go further. The hold feature may be implemented with an actual button, a separate proximity detector or by detecting the presence of a characteristic condition in the digitized data, such as loss of correlation or velocity in excess of a selected limit. A convenient place for an actual hold button is along the sides of the mouse near the bottom, where the thumb and the opposing ring finger grip the mouse. The gripping force used to lift the mouse engages the hold function. Hold may incorporate a brief delay upon either the release of the hold button, detection of proper proximity or the return of reasonable digitized values. During that delay any illumination control or AGC servo loops stabilize. A new reference frame is taken prior to the resumption of motion detection.

Abstract: A pen-type optical mouse device indicates a cursor position or inputs writing or a movement of the pen-type optical mouse. An aspect of the pen-type optical mouse is to calculate coordinate values of the mouse device in accordance with a movement of the pen-type optical mouse device. The pen-type optical device includes an image sensor on a side of the interior of a main body of pen-type the mouse device, thereby allowing the pen-type optical mouse device to be slim and easy to hold.

Abstract: Optical sensors are used extensively for displacement measurement. A cost-effective optical displacement sensor will be invaluable in applications where very high resolutions are not required. In this work, the optical mouse has been investigated to determine its suitability for two-dimensional displacement measurement. While the mouse worked only on objects with opaque surfaces, experiments conducted with a commercial unit with 0.0635 mm resolution showed that highly linear (average R2-value of 0.9914) and low error (mean square error (M.S.E.) value below 0.018 mm2) measurements could be attained. On the flipside, the unit could only operate if placed at a distance no greater than 1.25 mm from the object surface. Overall, the optical mouse has been found to be a viable two-dimensional displacement sensor. Its efficacy was demonstrated in measuring the viscoelastic elongation of polyethylene.