Sensing devices

This application is a Continuation of pending U.S. patent application Ser. No. 14/601,429, filed Jan. 21, 2015 and entitled “SENSING DEVICES”, which is a Continuation of U.S. patent application Ser. No. 12/953,898, filed Nov. 24, 2010 and entitled “SENSING DEVICES” (now U.S. Pat. No. 8,970,541, issued Mar. 3, 2015).

The invention relates to a sensing device, and more particularly to a capacitive touch sensing device.

A conventional capacitive touch sensing device comprises a sensing array which consists of horizontal sensing electrodes and vertical sensing electrodes. During the operation of the sensing device, the coupling of noise onto the sensing electrodes from the surrounding environment may cause errors. For example, when the sensing device is integrated with a display device, noise may be coupled onto the sensing electrodes from display electrodes of the display device. FIG. 1 shows capacitance, which is present on the sensing electrodes when the sensing electrodes are integrated on the color filter substrate of the display device. In FIG. 1 , only one horizontal sensing electrode T 10 and one vertical sensing electrode R 10 are shown. A capacitance Cpar is formed between the horizontal sensing electrode T 10 and a voltage terminal Vcom, and another capacitance is formed between the vertical sensing electrode R 10 and the voltage terminal Vcom. When a grounded object 10 approaches the crossing point of the horizontal sensing electrode T 10 and the vertical sensing electrode R 10 , the crossing capacitance Ccross between the horizontal sensing electrode T 10 and the vertical sensing electrode R 10 is decreased. The variation of the value of the crossing capacitance Ccross can be measured by applying a transmitting signal to the horizontal sensing electrode T 10 from a transmitter 11 and by detecting the coupled signal on the vertical sensing electrode R 10 using a receiver 12 .

FIG. 2 shows a conventional pattern of horizontal sensing electrodes and vertical sensing electrodes in a capacitive touch sensing device. Between crossing points of horizontal sensing electrodes T 1 ˜T 3 and vertical sensing electrodes R 1 ˜R 3 , these sensing electrodes are widened to firm diamond shapes. Referring to FIG. 2 , all of the diamond shapes of one horizontal sensing electrode receive the same transmitting signal from a transmitter. In other words, the diamond shapes on the same horizontal row are belonged to the same horizontal sensing electrode and are not controlled independently by a transmitter, which reduces types of cross-capacitance measurement methods.

One exemplary embodiment of a sensing device is provided. The sensing device comprises at least one first receiving electrode, a plurality of first electrodes, and at least one second electrode. The at least one first receiving electrode extends in a first direction. The plurality of first electrodes are connected electrically by a first signal line. The width of each first electrode is larger than a width of the first signal line. The first signal line passes through the plurality of first electrodes. The first signal line and the plurality of first electrodes are overlapped. The plurality of first electrodes have a first voltage level. The at least one second electrode has a second voltage level. The plurality of first electrodes and the at least one second electrode are disposed on the same row which extends in a second direction intersecting the first direction. The first voltage level is different from the second voltage level. The first signal line crosses the at least one first receiving electrode and the at least one second electrode.

Another exemplary embodiment of a sensing device is provided. The sensing device comprises a plurality of first receiving electrodes, a plurality of first electrodes, and a plurality of second electrodes. The plurality of first receive electrode extending in a first direction. The plurality of first electrodes extend in a second direction intersecting the first direction. The plurality of first electrodes have a first voltage level and are electrically connected by a first signal line. The first signal line passes through the plurality of first electrodes. The first signal line and the plurality of first electrodes are overlapped. The width of each first electrode is larger than a width of the first signal line. The plurality of second electrodes extend in the second direction. The plurality of second electrodes have a second voltage level. The first voltage level is different from the second voltage level. One of the plurality of first electrodes and one of the first receiving electrode are respectively closest to one of the plurality of second electrodes, and the one of the plurality of second electrodes is disposed between the one of the plurality of first electrodes and the one of the first receiving electrode in the second direction. The first signal line crosses the plurality of first receiving electrode and the plurality of second electrode.

A detailed description is given in the following embodiments with reference to the accompanying drawings.

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 shows capacitance, which is present on the sensing electrodes when the sensing electrodes are integrated on the color filter substrate of the display device;

FIG. 2 shows a conventional pattern of horizontal sensing electrodes and vertical sensing electrodes in a capacitive touch sensing device;

FIG. 3 shows an exemplary embodiment of a sensing device;

FIG. 4 shows an exemplary embodiment of a sensing array;

FIG. 5 shows an exemplary embodiment of a sensing array;

FIG. 6 shows an exemplary embodiment of a display device; and

FIG. 7 shows an exemplary embodiment of an electronic device.

The following description is of the best-contemplated mode of carrying out the invention. This description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention is best determined by reference to the appended claims.

Sensing devices are provided. In an exemplary embodiment of a sensing device in FIG. 3 , a sensing device 3 generates a sensing signal according to a touch of an object and comprises a sensing array 30 , at least one transmitter 31 , and at least one receiver 32 . In the embodiment, the sensing device 3 is a capacitive touch sensing device. FIG. 4 shows an exemplary embodiment of the sensing array 30 . Referring to FIG. 4 , the sensing array 30 comprises a plurality of transmitting electrodes and a plurality of receiving electrodes. In the embodiment, eight receiving electrodes R 1 ˜R 8 are given as an example. The receiver 32 are coupled to the receiving electrodes R 1 ˜R 8 . The receiving electrodes R 1 ˜R 8 extend in a first direction, for example the vertical direction. The receiving electrodes R 1 ˜R 8 are arranged in turn from the left side to the right side, as shown in FIG. 4 . The transmitting electrodes are controlled by the transmitter 31 . The transmitting electrodes are disposed on rows. The rows extend in a second direction intersecting the first direction, for example the horizontal direction, and the rows are arranged in turn from the upper side to the lower side, as shown in FIG. 4 .

In FIG. 4 , four rows ROW 1 ˜ROW 4 are given as an example. For each row, transmitting electrodes are divided into four groups A˜D. Referring to FIG. 4 , in the row ROW 1 , there are transmitting electrodes T 1 A 1 and T 1 A 2 (group A), T 1 B 1 and T 1 B 2 (group B), T 1 C 1 and T 1 C 2 (group C), and T 1 D 1 and T 1 D 2 (group D). In the row ROW 2 , there are transmitting electrodes T 2 A 1 and T 2 A 2 , T 2 B 1 and T 2 B 2 , T 2 C 1 and T 2 C 2 , and T 2 D 1 and T 2 D 2 . In the row ROW 3 , there are transmitting electrodes T 3 A 1 and T 3 A 2 , T 3 B 1 and T 3 B 2 , T 3 C 1 and T 3 C 2 , and T 3 D 1 and T 3 D 2 . In the row ROW 4 , there are transmitting electrodes T 4 A 1 and T 4 A 2 , T 4 B 1 and T 4 B 2 , T 4 C 1 and T 4 C 2 , and T 4 D 1 and T 4 D 2 . In each row, one set of four transmitting electrodes respectively belonging to the groups A˜D are congregated. In FIG. 4 , two sets are given as an example for each row. For example, in the row ROW 1 , the transmitting electrodes T 1 A 1 , T 1 B 1 , T 1 C 1 , and T 1 D 1 form one set, and the transmitting electrodes T 1 A 2 , T 1 B 2 , T 1 C 2 , and T 1 D 2 form the other set. In the embodiment, there are four transmitting electrodes in one set. However, in other embodiments, based on the pattern of the transmitting electrodes in FIG. 5 , the number of transmitting electrode sets on one row and the number of transmitting electrodes in one set can be determined according to system requirement, without limitation.

Moreover, in each row, the transmitting electrodes belonging to the same group are coupled to the same signal line for receiving the same signal. For example, in the row ROW 1 , the transmitting electrodes T 1 A 1 and T 1 A 2 belonging to the group A are coupled to a signal line L 1 A, the transmitting electrodes T 1 B 1 and T 1 B 2 belonging to the group B are coupled to a signal line L 1 B, the transmitting electrodes T 1 C 1 and T 1 C 2 belonging to the group C are coupled to a signal line L 1 C, and the transmitting electrodes T 1 D 1 and T 1 D 2 belonging to the group D are coupled to a signal line LID. In the rows ROW 2 ˜ROW 4 , the signal lines L 2 A˜L 2 D, L 3 A˜L 3 D, and L 4 A˜L 4 D are coupled to the corresponding transmitting electrodes according to the previous like descriptions. Thus, related descriptions are omitted here. The signal lines L 1 A˜L 1 D, L 2 A˜L 2 D, L 3 A˜L 3 D, and L 4 A˜L 4 D are coupled to the transmitter 31 .

Referring to FIG. 4 , near the crossing point between the receiving electrodes R 1 ˜R 8 and the rows ROW 1 ˜ROW 4 , the receiving electrodes R 1 ˜R 8 are widened to form diamond shapes and are in illustrated by dense dots, and the transmitting electrodes in the rows ROW 1 ˜ROW 4 are also widened to form diamond shapes and are in illustrated by sparse dots.

In the following, the transmitting electrodes in the row ROW 1 and the receiving electrodes R 1 ˜R 8 are given as an example for description. For the first set of transmitting electrodes in the row ROW 1 , the transmitting electrodes T 1 A 1 and T 1 B 1 are respectively disposed on the two sides of the receiving electrode R 1 , the transmitting electrodes T 1 B 1 and T 1 C 1 are respectively disposed on the two sides of the receiving electrode R 2 , and transmitting electrodes T 1 C 1 and T 1 D 1 are respectively disposed on the two sides of the receiving electrode R 3 . For the second set of the transmitting electrodes in the row ROW 1 , the transmitting electrodes T 1 A 2 and T 1 B 2 are respectively disposed on the two sides of the receiving electrode R 5 , the transmitting electrodes T 1 B 2 and T 1 C 2 are respectively disposed on the two sides of the receiving electrode R 6 , and the transmitting electrodes T 1 C 2 and T 1 D 2 are respectively disposed on the two sides of the receiving electrode R 7 . Note that the transmitting electrode T 1 D 1 of the first set and the transmitting electrode T 1 A 2 of the second set are respectively disposed on the two sides of the receiving electrode R 4 . The transmitting electrode T 1 D 2 is also disposed on one side of the receiving electrode R 8 , and another transmitting electrode T 1 A 3 which is coupled to the signal line L 1 A is disposed on the other side of the receiving electrode R 8 .

For the row ROW 1 , in one transmitting electrode set, the transmitting electrodes respectively belonging to the groups A−D are independently controlled by the transmitter 31 respectively through the signal lines L 1 A˜L 1 D. For example, when the receiver 32 measures a crossing capacitance between two adjacent transmitting electrodes on one row and a specific receiving electrode, the transmitter 31 provides a transmitting signal to the two adjacent transmitting electrodes. The receiver 32 generates the sensing signal according to the signal level of the specific receiving electrodes which is induced by the transmitting signal through the crossing capacitance. Moreover, the transmitter 31 provides a predetermined voltage level to the other transmitting electrodes on the row ROW 1 which do not receive the transmitting signal from the transmitter 31 . In the embodiment, the predetermined voltage level can be a voltage level of a ground. In another embodiment in which a differential measurement is used, when the receiver 32 measures a crossing capacitance between two adjacent transmitting electrodes on one row and a specific receiving electrode which is coupled one input terminal of the receiver 32 , the transmitter 31 provides a transmitting signal to the two adjacent transmitting electrodes. Moreover, the transmitter 31 provides a voltage level with the polarity inverse to the polarity of the voltage level of the transmitting signal to the transmitting electrodes adjacent to the receiving electrode which is coupled to the other terminal of the receiver 32 . If there are remaining transmitting electrodes which do not receive the transmitting signal and the voltage level with the inverse polarity, the transmitter 31 further provides a ground voltage level to these remaining transmitting electrodes.

Assume that a crossing capacitance between two adjacent transmitting electrodes T 1 A 1 and T 1 B 1 and the receiving electrode R 1 is measured. The transmitter 31 provides the transmitting signal to the adjacent transmitting electrodes T 1 A 1 and T 1 B 1 , respectively, through the signal lines L 1 A and L 1 B. The transmitter 31 provides the predetermined voltage level to the other transmitting electrodes T 1 C 1 , T 1 D 1 , T 1 C 2 , and T 1 D 2 which do not receive the transmitting signal from the transmitter 31 .

Further assume that a crossing capacitance between two adjacent transmitting electrodes T 1 C 1 and T 1 D 1 and the receiving electrode R 3 is measured. The transmitter 31 provides a transmitting signal to the adjacent transmitting electrodes T 1 C 1 and T 1 D 1 respectively through the signal lines L 1 C and L 1 D. The transmitter 31 provides the predetermined voltage level to the other transmitting electrodes T 1 A 1 , T 1 B 1 , T 1 A 2 , and T 1 B 2 which do not receive signals from the transmitter 31 .

Assume the sensing array in FIG. 4 is applied in a differential measurement, the receiver 32 is implemented by is a differential receiver circuit with two input terminals. When a crossing capacitance between two adjacent transmitting electrodes T 1 A 1 and T 1 B 1 and the receiving electrode R 1 is measured. The transmitter 31 provides the transmitting signal to the adjacent transmitting electrodes T 1 A 1 and T 1 B 1 , respectively, through the signal lines L 1 A and L 1 B. One input terminal of the receiver 32 is coupled to the receiving electrode R 1 , and the other input terminal thereof is coupled to the receiving electrode R 3 separated from the transmitting electrodes T 1 A 1 and T 1 B 1 , as shown in Table 1. Moreover, the other transmitting electrodes T 1 C 1 , T 1 D 1 , T 1 C 2 , and T 1 D 2 which do not receive signals from the transmitter 31 are connected to the fixed voltage level, such as a voltage level of a ground. When a crossing capacitance between two adjacent transmitting electrodes T 1 C 1 and T 1 D 1 and the receiving electrode R 3 is measured. The transmitter 31 provides a transmitting signal to the adjacent transmitting electrodes T 1 C 1 and T 1 D 1 respectively through the signal lines L 1 C and L 1 D. One input terminal of the receiver 32 is coupled to the receiving electrode R 3 , and the other terminal thereof is coupled to the receiving electrode R 5 or R 1 separated from the transmitting electrodes T 1 C 1 and T 1 D 1 , as shown in Table 1. Moreover, the other transmitting electrodes T 1 A 1 , T 1 B 1 , T 1 A 2 , and T 1 B 2 which do not receive signals from the transmitter 31 are connected to the fixed voltage level. According to the differential capacitance measurement, when the sensing device 3 with the sensing array of FIG. 4 is integrated with a display device, the noise on the measured receiving electrode resulted from display electrodes of the display device or from other sources can be eliminated.

FIG. 5 shows another exemplary embodiment of the sensing array 30 . Referring to FIG. 5 , the sensing array 30 comprises a plurality of transmitting electrodes and a plurality of receiving electrodes. In the embodiment, four receiving electrodes R 1 ′˜R 4 ′ are given as an example. The receiver 32 are coupled to the receiving electrodes R 1 ′˜R 4 ′. The receiving electrodes R 1 ′˜R 4 ′ extends in a first direction, for example the vertical direction. The receiving electrodes R 1 ′˜R 4 ′ are arranged in turn from the left side to the right side, as shown in FIG. 5 . The transmitting electrodes are controlled by the transmitter 31 . The transmitting electrodes are disposed on rows. The rows extend in a second direction intersecting the first direction, for example the horizontal direction, and the rows are arranged in turn from the upper side to the lower side, as shown in FIG. 5 .

In FIG. 5 , four rows ROW 1 ′˜ROW 4 ′ are given as an example. For each row, transmitting electrodes are divided into two groups A′ and B′. Referring to FIG. 5 , in the row ROW 1 ′, there are transmitting electrodes T 1 A′ 1 ˜T 1 A′ 4 (group A) and T 1 B′ 1 ˜T 1 B′ 4 (group B′). In the row ROW 2 ′, there are transmitting electrodes T 2 A′ 1 ˜T 2 ′A 4 and T 2 B′ 1 ˜T 2 B′ 4 . In the row ROW 3 ′, there are transmitting electrodes T 3 A′ 1 ˜T 3 A′ 4 and T 3 B′ 1 ˜T 3 B′ 4 . In the row ROW 4 ′, there are transmitting electrodes T 4 A′ 1 ˜T 4 A′ 4 and T 4 B′ 1 ˜T 4 B′ 4 . In each row, one set of the four transmitting electrodes, two transmitting electrodes belonging to the group A and the other two transmitting electrodes belonging to the group B, are congregated. In FIG. 5 , two sets are given as example for each row. For example, in the row ROW 1 ′, the transmitting electrodes T 1 A′ 1 ˜T 1 A′ 2 and T 1 B′ 1 ˜T 1 B′ 2 form one set, and the transmitting electrodes T 1 A′ 3 ˜T 1 A′ 4 and T 1 B′ 3 ˜T 1 B′ 4 form the other set. In the embodiment, there are four transmitting electrodes belonging to the two groups A and Bin one set. However, in other embodiments, based on the pattern of the transmitting electrodes in FIG. 5 , the number of transmitting electrodes in one set and the number of groups of the transmitting electrodes in one set can be determined according to system requirement, without limitation.

Moreover, in each row, the transmitting electrodes belonging to the same group are coupled to the same signal line for receiving the same signal. For example, in the row ROW 1 ′, the transmitting electrodes T 1 A′ 1 ˜T 1 A′ 4 belonging to the group A are coupled to a signal line L 1 A′, and the transmitting electrodes T 1 B′ 1 ˜T 1 B′ 4 belonging to the group B are coupled to a signal line L 1 B′. In the rows ROW 2 ′˜ROW 4 ′, signal lines L 2 A′˜L 2 B′, L 3 A′˜L 3 B′, and L 4 A′˜L 4 B′ are coupled to the corresponding transmitting electrodes according to the previous like descriptions. Thus, related descriptions are omitted here. The signal lines L 1 A′˜L 1 B′, L 2 A′˜L 2 B′, L 3 A′˜L 3 B′, and L 4 A′˜L 4 B′ are coupled to the transmitter 31 .

Referring to FIG. 5 , near the crossing point between the receiving electrodes R 1 ′˜R 4 ′ and the rows ROW 1 ′˜ROW 4 ′, the receiving electrodes R 1 ′˜R 4 ′ are widened to form diamond shapes and are in illustrated by dense dots, and the transmitting electrodes in the rows ROW 1 ′˜ROW 4 ′ are also widened to form triangular shapes and are in illustrated by sparse dots.

In the following, the transmitting electrodes in the row ROW 1 ′ and the receiving electrodes R 1 ′˜R 4 ′ are given as an example for description. For the first set of transmitting electrodes in the row ROW 1 ′, the transmitting electrodes T 1 A′ 1 and T 1 A′ 2 are respectively disposed on the two sides of the receiving electrode R 1 ′, and the transmitting electrodes T 1 B′ 1 and T 1 B′ 2 are respectively disposed on the two sides of the receiving electrode R 2 ′. For the second set of transmitting electrodes in the row ROW 1 ′, the transmitting electrodes T 1 A′ 3 and T 1 A′ 4 are respectively disposed on the two sides of the receiving electrode R 3 ′, and the transmitting electrodes T 1 B′ 3 and T 1 B′ 4 are respectively disposed on the two sides of the receiving electrode R 4 ′.

For the row ROW 1 ′, in one transmitting electrode set, the transmitting electrodes respectively belonging to the groups A˜B are independently controlled by the transmitter 31 respectively through the signal lines L 1 A′˜L 1 B′. For example, when the receiver 32 measures a crossing capacitance between two adjacent transmitting electrodes on one row and a specific receiving electrode, the transmitter 31 provides transmitting signals to the two adjacent transmitting electrodes. The receiver 32 generates a sensing signal according to the signal level of the specific receiving electrodes which is induced by the transmitting signal through the crossing capacitance. Moreover, the transmitter 31 provides a predetermined voltage level to the other transmitting electrodes on the row ROW 1 ′ which do not receive the transmitting signal from the transmitter 31 . In the embodiment, the predetermined voltage level can be a voltage level of a ground. In another embodiment in which a differential measurement is used, when the receiver 32 measures a crossing capacitance between two adjacent transmitting electrodes on one row and a specific receiving electrode which is coupled one input terminal of the receiver 32 , the transmitter 31 provides a transmitting signal to the two adjacent transmitting electrodes. Moreover, the transmitter 31 provides a voltage level with the polarity inverse to the polarity of the voltage level of the transmitting signal to the transmitting electrodes adjacent to the receiving electrode which is coupled to the other terminal of the receiver 32 . If there are remaining transmitting electrodes which do not receive the transmitting signal and the voltage level with the inverse polarity, the transmitter 31 further provides a ground voltage level to these remaining transmitting electrodes.

Assume that a crossing capacitance between two adjacent transmitting electrodes T 1 A′ 1 and T 1 A′ 2 and the receiving electrode R 1 ′ is measured. The transmitter 31 provides a transmitting signal to the adjacent transmitting electrodes T 1 A′ 1 and T 1 A′ 2 through the signal line L 1 A′. The transmitter 31 provides the predetermined voltage level to the other transmitting electrodes T 1 B′ 1 ˜T 1 B′ 4 which do not receive the transmitting signal from the transmitter 31 .

Further assume that a crossing capacitance between two adjacent transmitting electrodes T 1 B′ 1 and T 1 B′ 2 and the receiving electrode R 2 is measured. The transmitter 31 provides a transmitting signal to the adjacent transmitting electrodes T 1 B′ 1 and T 1 B′ 2 through the signal line L 1 B′. The transmitter 31 provides the predetermined voltage level to the other transmitting electrodes T 1 A′ 1 ˜T 1 A′ 4 which do not receive the transmitting signal from the transmitter 31 are connected to the fixed voltage level.

Assume the sensing array in FIG. 5 is applied in a differential measurement, the receiver 32 is implemented by is a differential receiver circuit with two input terminals. Assume that a crossing capacitance between two adjacent transmitting electrodes T 1 A′ 1 and T 1 A′ 2 and the receiving electrode R 1 ′ is measured. The transmitter 31 provides a transmitting signal to the adjacent transmitting electrodes T 1 A′ 1 and T 1 A′ 2 through the signal line L 1 A′. One input terminal of the receiver 32 is coupled to the receiving electrode R 1 ′, and the other terminal thereof is coupled to the receiving electrode R 2 ′ adjacent to the receiving electrode R 1 ′, as shown in Table 2. Moreover, the other transmitting electrodes T 1 B′ 1 ˜T 1 B′ 4 which do not receive signals from the transmitter 31 are connected to the predetermined voltage level. Assume that a crossing capacitance between two adjacent transmitting electrodes T 1 B′ 1 and T 1 B′ 2 and the receiving electrode R 2 is measured. The transmitter 31 provides a transmitting signal to the adjacent transmitting electrodes T 1 B′ 1 and T 1 B′ 2 through the signal line L 1 B′. One input terminal of the receiver 32 is coupled to the receiving electrode R 2 ′, and the other terminal thereof is coupled to the receiving electrode R 1 ′ or R 3 ′ adjacent to the specific receiving electrode R 2 ′, as shown in Table 2. Moreover, the other transmitting electrodes T 1 A′ 1 ˜T 1 A′ 4 which do not receive signals from the transmitter 31 are connected to the predetermined voltage level. In some embodiments, the predetermined voltage level can be a voltage level of a ground or a voltage level with the polarity inverse to the polarity of the voltage level of the transmitting signal. In the case in which the predetermined voltage level is a voltage level with the polarity inverse to the polarity of the voltage level of the transmitting signal, according to the differential capacitance measurement, the output signal of the receiver 32 represents the sum of the two cross capacitance values related to the measured receiving electrodes due to the two signals with complementary polarities. Moreover, according to the differential capacitance measurement, when the sensing device 3 with the sensing array of FIG. 5 is integrated with a display device, the noise on the measured receiving electrode resulted from display electrodes of the display device or from other sources can be eliminated.

FIG. 6 schematically shows a display apparatus 6 employing the disclosed sensing device 3 with the sensing array of FIG. 4 or FIG. 5 . Generally, the apparatus 6 includes a controller 60 and the sensing device 3 shown in FIG. 3 , etc. The controller 60 is operatively coupled to the sensing device 3 and provides control signals to the sensing device 3 .

FIG. 7 schematically shows an electronic device 7 employing the disclosed display apparatus 6 . The electronic device 7 may be a portable device such as a PDA, digital camera, notebook computer, tablet computer, cellular phone, a display monitor device, or similar. Generally, the electronic device 7 comprises an input unit 70 and the display apparatus 6 shown in FIG. 6 , etc. Further, the input unit 70 is operatively coupled to the display apparatus 6 and provides input signals to the display apparatus 6 . The controller 60 of the display apparatus 6 provides the control signals to the sensing device 3 according to the input signals.

While the invention has been described by way of example and in terms of the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.