Patent Description:
Knob devices are often used in general electronic apparatus, such as the knob for volume adjustment on an audio player, the knob for frequency adjustment on a radio and the knob for air conditioning/air volume adjustment on a car console, where many of these electronic apparatuses are equipped with a touch panel. Therefore, how to integrate the knob device and the touch panel to assist user in control has become an issue. When a touch panel is equipped with a knob, a position of the knob may be offset for some reasons. For example, the position of the knob may be offset for positioning error or deterioration of the laminated material due to the aging. The offset of the position will cause the wrong determination of the rotation angle of the knob, and further affect the stability and reliability of the knob. Thus, a novel calibration method and associated architecture are needed without introducing any side effect or in a way that is less likely to introduce a side effect.

<CIT> discloses an operation input device. <CIT> discloses a touch screen input device. <CIT> discloses an information handling system input device. <CIT> discloses a touch screen that is associated with an electronic display.

The invention aims at providing a technique for determining an accurate position of the center of a knob. This is achieved by a calibration method and an associated calibration apparatus according to the independent claims. The dependent claims pertain to corresponding further developments and improvements.

As will be seen more clearly from the detailed description below, the calibration method is for a knob applicable to a touch panel, wherein the knob comprises at least one sensing pad. The calibration method further comprises: obtaining at least one sensed position of each sensing pad of said at least one sensing pad by sensing a position of said each sensing pad through the touch panel; and calculating a position of a center of the knob by using a formula of a radius of a circumscribed circle according said at least one sensed position of said each sensing pad.

The calibration apparatus is for a knob applicable to a touch panel, wherein the knob comprises at least one sensing pad. The calibration apparatus further comprises a sensing processing circuit and a calculation circuit. The sensing processing circuit is configured to obtain at least one sensed position of each sensing pad of said at least one sensing pad by sensing a position of said each sensing pad through the touch panel. The calculation circuit is configured to calculate a position of a center of the knob by using a formula of a radius of a circumscribed circle according said at least one sensed position of said each sensing pad.

The present invention calibration method and calibration apparatus are able to obtain the new center of the knob by calculating. Through pressing or rotating the knob, the position of one or more sensing pads can be obtained. The new center of the knob can be calculated according to enough sensed positions of one or more sensing pads. The calibration method of the present invention provides an accurate position of the center of the knob, thereby preventing the rotation angle of the knob from being determined erroneously and improving the stability and reliability of the knob.

In the following, the invention is further illustrated by way of example, taking reference to the following drawings.

Refer to <FIG> is a diagram of a calibration apparatus <NUM> for a knob <NUM> applicable to a touch panel <NUM>. As shown in <FIG>, the knob <NUM> is arranged on the touch panel <NUM>, and comprises at least one sensing pad <NUM>. In one embodiment not covered by the claims, the knob <NUM> may comprise only a single sensing pad <NUM>. In another embodiment according to the invention, the knob <NUM> may comprise multiple sensing pads <NUM>. For brevity, only one sensing pad <NUM> is shown in <FIG>. Taking the knob <NUM> with only a single sensing pad <NUM> as an example, when a user operates the knob <NUM> by contacting the knob <NUM>, the knob <NUM> forms a conductive path through the sensing pad <NUM>. This path allows the user's finger touching the knob <NUM> to be connected to the touch panel <NUM> through the conductive path, which is equivalent to allowing the user to indirectly control the touch panel <NUM>. In other words, when the user touches the knob <NUM>, the touch panel <NUM> generates a sensing signal in response to a loop formed by the touch panel <NUM>, the knob <NUM> and the user. The sensing signal comprises position information of the sensing pad <NUM>. Furthermore, when the user rotates the knob <NUM>, the touch panel <NUM> generates multiple sensing signals in response to the movement and positions of the sensing pad <NUM>, such that a rotation angle may be calculated through the positions of the sensing pad <NUM>. In addition, the calibration apparatus <NUM> for the knob <NUM> is provided for performing calibration on the position of the knob. The calibration apparatus <NUM> comprises a sensing processing circuit <NUM> and a calculation circuit <NUM>. The sensing processing circuit <NUM> is configured to obtain at least one sensed position of each sensing pad <NUM> by sensing a position of each sensing pad <NUM> through the touch panel <NUM>. The calculation circuit <NUM> is configured to calculate a position of a center of the knob <NUM> by using a formula of a radius of a circumscribed circle according the at least one sensed position of each sensing pad <NUM>, such that a new position of the center of the knob <NUM> may be obtained to replace an original position of the center of the knob <NUM>.

A position of the knob may be offset for some reason, such that the rotation angle may be erroneously determined for an offset center of the knob. Refer to <FIG> is a diagram illustrating a position offset of the knob <NUM> and affected rotation angles. As shown in <FIG>, for example, the knob <NUM> is offset from an original position to an offset position, such that a center of the knob <NUM> is also offset. Assuming that the sensing pad <NUM> is rotated from a position A to a position B (in the offset position), the position B of the sensing pad <NUM> is the sensed position, such that the sensing pad <NUM> is determined being rotated by a rotation angle θ1 relative to the offset center. Assuming that the center of the knob <NUM> is offset and not calibrated, the position of the center is regarded as the position of the original center. As a result, since the sensed position of the sensing pad <NUM> is the position B, a rotation angle of the sensing pad <NUM> relative to the original center is calculated to be θ2, such that the rotation angle of the knob is erroneously determined as the rotation angle θ2. Therefore, the position of the center of the knob has to be corrected.

Refer to <FIG> is a flowchart <NUM> of a calibration method for the knob <NUM>. The calibration method <NUM> may be employed by the calibration apparatus <NUM> shown in <FIG>, and comprises the following steps.

The calibration method uses a formula of a radius of a circumscribed circle to calculate a new position of the center of the knob according to the multiple sensed positions of the sensing pad(s). A distribution range of the multiple sensed positions has to be not smaller (e.g., greater and equal) than a quarter circle of the knob for accuracy of calculation. Therefore, in response to the knobs having different numbers of sensing pads, the knobs are required to be rotated at different angles or be pressed.

Refer to <FIG> is a diagram illustrating the calibration method for the knob <NUM> with only a single sensing pad <NUM>. For obtaining the sensed positions distributed along a partial perimeter not smaller than a quarter circle of the knob <NUM>, the knob <NUM> with only a single sensing pad <NUM> needs to be rotated at least a quarter circle of the knob. In other words, the knob <NUM> with only a single sensing pad <NUM> needs to be rotated by at least <NUM> degrees. The sensed positions are generated in response a touch and rotation event of the knob <NUM>. An original position and a final position of the sensing pad <NUM> are distributed along a partial perimeter not smaller than a quarter circle of the knob, such that the original position, the final position and any position on the movement track of the single sensing pad <NUM> can be used to calculate the position of the center of the knob <NUM>.

Refer to <FIG> is a diagram illustrating the calibration method for the knob <NUM> with two sensing pads <NUM> according to an embodiment of the present invention. Similarly, for obtaining the sensed positions distributed along a partial perimeter not smaller than a quarter circle of the knob <NUM>, the knob <NUM> having two sensing pad 120A and 120B needs to be rotated. The sensed positions are generated in response a touch and rotation event of the knob <NUM>. The two sensing pads 120A and 120B have two rotation tracks respectively. A total track is formed by summing up the rotation tracks of the two sensing pads 120A and 120B, and the total track has to traverse at least a quarter circle of the knob. As shown in <FIG>, an original position of the sensing pad 120A and a final position of the sensing pad 120B are distributed along a partial perimeter not smaller than a quarter circle of the knob, such that the original position of the sensing pad 120A, the final position of the sensing pad 120B and any position on the rotation track of any sensing pad can be used to calculate the position of the center of the knob <NUM>. It should be noticed that an overlapped part of the two rotation tracks is considered as one rotation track in the total track.

Refer to <FIG> is a diagram illustrating the calibration method for the knob <NUM> having three single sensing pads <NUM> with a distribution range being smaller than a quarter circle of the knob according to an embodiment of the present invention. Similarly, for obtaining the sensed positions distributed along a partial perimeter not smaller than a quarter circle of the knob <NUM>, the knob <NUM> having three sensing pad 120A, 120B and 120C needs to be rotated. The sensed positions are generated in response a touch and rotation event of the knob <NUM>. The three sensing pads 120A, 120B and 120C have three rotation tracks, respectively. A total track is formed by summing up the rotation tracks of the three sensing pads 120A, 120B and 120C, and the total track has to traverse at least a quarter circle of the knob. As shown in <FIG>, an original position of the sensing pad 120A and a final position of the sensing pad 120C are distributed along a partial perimeter not smaller than a quarter circle of the knob, such that the original position of the sensing pad 120A, the final position of the sensing pad 120C and any position on the rotation track of any sensing pad can be used to calculate the position of the center of the knob <NUM>. It should be noticed that an overlapped part of the three rotation tracks is considered as one rotation track in the total track. Furthermore, if a knob has more than three sensing pads with distribution range being smaller than a quarter circle of the knob, the total track also has to traverse at least a quarter circle of the knob, in order to obtain the necessary sensed positions.

Refer to <FIG> is a diagram illustrating the calibration method for the knob <NUM> with three single sensing pads <NUM> with a distribution range being not smaller than a quarter circle of the knob. For obtaining the sensed positions distributed along a partial perimeter not smaller than a quarter circle of the knob, the knob <NUM> having three sensing pad 120A, 120B and 120C may be directly pressed without being rotated. As shown in <FIG>, since the three sensing pad 120A, 120B and 120C are distributed along a partial perimeter not smaller than a quarter circle of the knob, the positions of the three sensing pad 120A, 120B and 120C can be used to calculate the position of the center of the knob <NUM>. The sensed positions are generated in response a touch and press event of the knob <NUM>. It should be noticed that a press event of the knob <NUM> is to obtain the positions of the three sensing pad 120A, 120B and 120C. In some embodiments, a slightly touch can let the touch panel sense the positions of the three sensing pads of the knob. Furthermore, if a knob has more than three sensing pads with a distribution range being not smaller than a quarter circle of the knob, the position of the center of the knob can be calculated according to the original positions of the sensing pads.

Specifically, there are actually some differences in the positions of the center of the knob calculated according to different sensed positions in the rotation track. Therefore, at least one other position of the center of the knob can be calculated according another sensed positions of each sensing pad, and an average position of the center of the knob can be obtain by performing average calculation on multiple calculated positions of the center of the knob to make the calibrated position of the center more accurate, where the multiple calculated positions comprise the position and the other position of the center of the knob.

Claim 1:
A calibration method for a knob (<NUM>) applicable to a touch panel (<NUM>), the knob (<NUM>) comprising at least one sensing pad (<NUM>), the calibration method comprising:
obtaining at least one sensed position of each sensing pad of said at least one sensing pad (<NUM>) by sensing a position of said each sensing pad through the touch panel (<NUM>); and
calculating a position of a center of the knob (<NUM>) by using a formula of a radius of a circumscribed circle according to said at least one sensed position of said each sensing pad (<NUM>);
wherein said at least one sensed position of said each sensing pad (<NUM>) comprises multiple sensed positions that are obtained in response to a touch and rotation event of the knob (<NUM>);
characterized in that the knob (<NUM>) comprises only two sensing pads (120A, 120B), and calculating the position of the center of the knob (<NUM>) by using the formula of the radius of the circumscribed circle according to said at least one sensed position of said each sensing pad (120A, 120B) comprises:
sensing rotation tracks of the two sensing pads (120A, 120B) according to sensed positions of the two sensing pads (120A, 120B), respectively, wherein a total track formed by summing up the rotation tracks of the two sensing pads (120A, 120B) traverses at least a quarter circle of the knob (<NUM>);
arranging the total track as a movement track of the two sensing pads (120A, 120B); and
calculating the position of the center of the knob (<NUM>) by using the formula of the radius of the circumscribed circle according to the movement track;
wherein an overlapped part of the two rotation tracks is considered as one rotation track.