KR20090107640A - Capacitive overlay touch screen apparatus and method for sensing objects thereof - Google Patents

Abstract

PURPOSE: A capacitive touch screen device and an object sensing method thereof are provided to sense an object in case it is positioned over the touch screen and measure 3D coordinates of the object. CONSTITUTION: A capacitive touch screen device comprises a sensor unit(11), a capacitance measuring unit(32) and a switch(31). The sensor unit is comprised of a plurality of sensors having capacitance variable according to the approach of an object. The capacitance measuring unit measures the capacitance of each sensor. The switch connects the sensors to the capacitance measuring unit.

Description

Capacitive overlay touch screen apparatus and method for sensing objects

The present invention relates to a capacitive touch screen device and an object sensing method thereof, and more particularly, to a capacitive touch screen device for dynamically merging a plurality of sensors by introducing a switch to a capacitive touch screen, and It relates to an object recognition method.

Current portable terminal devices, such as PDAs, PMPs, MP3 players, mobile phones, etc., are becoming smaller in size to facilitate their portability and mobility. As miniaturization of the portable terminal device proceeds, a touch screen method is adopted to allow a user to input or select information more conveniently in place of the conventional key button input method. The touch screen method is a method of directly inputting or selecting information by interfacing with a computer through a screen. When a touch of a human hand or an object is touched at a specific position of the screen, the touch screen detects coordinates of the touched position. The function corresponding to the coordinate value is executed by the software through the coordinate value. Accordingly, the touch screen provides a function as an information display unit and a function as an input unit.

The touch screen may be classified in various ways, and may be classified into a capacitive type, a resistive film type, a surface ultrasonic type, and an infrared type according to its operation principle. The resistive touch screen has a structure in which a resistive material is coated on a glass or transparent plastic plate and a polyester film is covered thereon. Insulation rods are installed at regular intervals so that the two surfaces do not touch each other. When the screen is touched, the resistance value changes and thereby the voltage is detected to detect the touch point.

The supersonic wave method is configured by attaching a transmitter that emits sound waves to one corner of the glass, a reflector that reflects sound waves at regular intervals, and a receiver on the opposite side thereof. An object such as a finger touches the screen. When it interferes with the path of sound waves, the point of time is calculated to detect the touch point.

In the infrared method, a matrix is formed by arranging an infrared LED, which is a light emitting device, and a phototransistor, which is a light receiving device, facing each other. When an object such as a finger approaches the inside of the matrix to block infrared rays, the sensor detects this and detects a touch point.

The capacitive coating generates a high frequency on the surface of the touch screen by coating a transparent special conductive metal on both sides of the glass and applying voltage to four corners of the screen. When an object such as a finger touches the screen, the controller detects a touch point by analyzing a high frequency waveform that changes. There are two types of capacitive methods: a single layer method using one ITO panel, which is a transparent conductive layer, and a dual layer method using two ITO panels.

In the conventional capacitive touch screen, when an object such as a finger touches the screen, capacitance of a plurality of sensors increases, and a capacitance measuring unit (not shown) measures the capacitance of each sensor to contact the object. can confirm.

However, the conventional capacitive touch screen has a limitation that it can operate only when an object such as a finger touches the screen surface. Some companies manufacture touch screens that support hovering function to check the proximity, but the maximum detection distance is less than 5mm, and it is difficult to commercialize due to its low stability.

One method of increasing the sensitivity of the capacitive touch screen is to increase the area of the sensor. However, if the sensor area becomes larger than the size of the object, it can be seen that the object is positioned on the sensor, but it is not possible to determine which direction on the sensor. Therefore, when the area of the sensor is largely increased, the sensitivity of the sensor is increased but the accuracy of the location information is lowered.

The present invention is to solve the above problems, the capacitive touch screen device that can detect the object and measure the three-dimensional coordinates of the object not only when the object is in contact with the surface of the screen but also located in the air And an object detection method thereby.

Another object of the present invention is to provide a capacitive touch screen device and a method for detecting an object by using the two or more capacitive measuring unit to shorten the time to measure the coordinates of the object when the object approaches the screen. do.

A capacitive touch screen device according to an embodiment of the present invention, a sensor unit consisting of a plurality of sensors whose capacitance changes in accordance with the approach of an object, a capacitance measuring unit for measuring the capacitance of the sensor, and the And a switch unit connecting a plurality of sensors to the capacitance measuring unit.

In the object detection method of the capacitive touch screen according to an embodiment of the present invention, detecting an capacitance change of a plurality of sensors constituting the sensor unit when the object approaches, some of the sensors according to the switch control sequence Connecting to the capacitance measuring unit, and measuring the capacitance of the connected sensors.

The present invention makes it possible to detect the object and measure the three-dimensional coordinates of the object even when the object is located in the air of the touch screen.

According to the present invention, the area of the sensor can be adjusted in various ways by dynamically merging the plurality of sensors using the switch unit, and thus the sensitivity and accuracy of the sensor can be adjusted.

The present invention shortens the time for measuring the coordinates of an object approaching the screen using two or more capacitance measuring units.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A is an exemplary diagram of a capacitive dual layer touch screen according to an embodiment of the present invention.

As shown in FIG. 1A, the sensor unit 11 of the capacitive dual layer touch screen according to the exemplary embodiment of the present invention is configured such that two ITO panels face each other with a transparent insulating film 12 interposed therebetween. .

1B and 1C are plan views of the upper ITO panel and the lower ITO panel constituting FIG. 1A.

As shown in FIG. 1B, in the upper ITO panel, a plurality of upper sensor pads 16 are arranged on the transparent insulating layer 12, and upper sensor leads connecting upper sensor pads 16 arranged on the same axis. (15) is arranged. One upper sensor lead 15 and a plurality of upper sensor pads connected to the upper sensor lead 15 constitute one sensor 17a.

As shown in FIG. 1C, in the lower ITO panel, a plurality of lower sensor pads 13 are arranged on the transparent insulating layer 12, and the lower sensor pads (or in a direction orthogonal to the upper sensor lead line 15). A lower sensor lead 14 connecting 13 is arranged. One lower sensor lead 14 and a plurality of lower sensor pads connected to the lower sensor lead 14 constitute one sensor 17b.

FIG. 1D is a cross-sectional view of the AA ′ portion of FIG. 1A. FIG.

As illustrated in FIG. 1D, the capacitive dual layer touch screen is configured such that the upper ITO panel of FIG. 1B and the lower ITO panel of FIG. 1C face each other with the transparent insulating layer 12 therebetween. The upper sensor lead 15 and the lower sensor lead 14 are arranged to be orthogonal to each other. The sensor lead is made of ITO to have transparent conductivity similarly to the sensor pad. A plurality of sensor pads connected by one sensor lead and the one sensor lead constitute one sensor, and a plurality of sensors gather to form one sensor unit 11.

2 is a block diagram of a capacitive touch screen device according to an embodiment of the present invention.

As shown in FIG. 2, the capacitive touch screen device according to an embodiment of the present invention includes a sensor unit 11 including a plurality of sensors whose capacitance changes according to an object approach, and the capacitance of the sensor. Capacitance measurement unit 32 for measuring the capacitance, the switch unit 31 for connecting the plurality of sensors to the capacitance measurement unit 32, the capacitance measurement in various combinations of the plurality of sensors according to a switch control sequence A switch control unit 33 for controlling the switch unit to be connected to the unit, and a coordinate measuring unit 34 for measuring three-dimensional coordinates of the approached object based on the switch control sequence and the measured capacitance of the switch control sequence. It includes.

The sensor unit 11 includes a plurality of sensors, for example, an upper first sensor 17a or a lower first sensor 17b, in which capacitance is changed when a conductive object such as a finger approaches.

In an embodiment of the present invention, the sensor pads 13 and 16 of the sensor are configured in a diamond shape, but in another embodiment, the sensor pads are configured in various shapes such as polygons such as triangles and squares or circles or ellipses. Can be.

In addition, in one embodiment of the present invention, the sensors 17a and 17b are formed by connecting the diamond pad sensor pads with the sensor leads 14 and 15, but in another embodiment, form a capacitance such as a rectangular shape. It can be configured in any form that it can.

In another embodiment of the present invention, the upper sensor and the lower sensor are arranged in an orthogonal form, but in another embodiment, the upper sensor and the lower sensor may cross each other at any angle. However, since the sensitivity of the sensor decreases as the crossing area of the sensors becomes wider, the crossing area of each sensor is preferably minimized. The number of sensors may vary depending on the area of the touch screen or the precision of the coordinate measurement of the touch screen.

The capacitance measuring unit 32 measures the capacitance of each sensor constituting the sensor unit 11. The capacitance measuring unit 32 may measure the capacitance by converting the capacitance change of the sensor into a voltage change, or may measure the capacitance by converting it into a charge amount change.

The switch unit 31 connects the plurality of sensors constituting the sensor unit 11 to the capacitance measuring unit 32. According to an embodiment of the present invention, the sensor lead of the upper sensor of the sensor unit 11 and the sensor lead of the lower sensor, for example, the upper sensor lead 15 and the lower sensor lead 14 of FIG. The capacitance measuring unit 32 is connected. The switch includes a variety of switches capable of opening and closing conducting wires, such as a CMOS switch using a transistor, a vacuum switch, a solid state switch, a mercury switch, and introducing the same into a touch screen device.

The switch control unit 33 controls the switch unit 31 to connect the plurality of sensors to the capacitance measuring unit 32 in various combinations according to a switch control sequence. The switch control sequence may be preset in a system including a touch screen, and may be variably set by software installed in the system. The switch control sequence may be changed by the user of the system.

The coordinate measuring unit 34 measures three-dimensional coordinates of the approached object based on the switch control sequence and the measured capacitance of the switch control sequence. When the capacitance of sensors corresponding to arbitrary coordinates is measured by the switch control sequence, the coordinate measuring unit 34 compares the coordinates with the capacitance to measure coordinates on the touch screen of the approached object. .

For example, when a user's finger approaches an arbitrary position of the sensor unit 11, the switch control unit 33 connects or disconnects each switch of the switch unit 31 according to a switch control sequence in the system. Let's do it. The switch control sequence may initially connect one of the switches of x1 to the switch of x6 and one of the switches of y1 to the switch of y6 in order. However, when the finger is located in the air without contacting the touch screen, the area of the sensor is not large enough to detect the finger. In this case, the switch control sequence is connected to two switches of the switch of x1 to the switch of x6 and the switch of y1 to the switch of y6 in sequence, such as x1 and x2, x2 and x3, x3 and x4, and the like. ) Can be connected.

If the finger cannot be detected even in the above sequence, the switch control sequence may be connected to the capacitance measuring unit 32 by connecting three switches of a switch of x1 to a switch of x6 and a switch of y1 to a switch of y6. Can be.

Through the above process, the touch screen device of the present invention can adjust the area of the sensor according to the switch control sequence, and can detect an object located in the air of the touch screen. In addition, it is possible to measure the exact coordinates of the object by adjusting the area of the sensor only to the extent that the object can be detected. In addition, the capacitive touch screen device according to an embodiment of the present invention uses a conventional capacitive touch screen panel as it is, and there is no large change in other parts, so that the detection and coordinates of objects located in the air without a large increase in manufacturing cost The advantage is that measurement is possible.

Hereinafter, a process of measuring three-dimensional coordinates of an object according to an embodiment of the present invention will be described with reference to the accompanying drawings.

3 is a diagram comparing capacitance of an x-axis sensor according to each switch control sequence.

When an object approaches the touch screen and the switch control unit 33 connects or disconnects the switches of the switch unit 31 according to the switch control sequence, the capacitance measuring unit 32 performs a The capacitance of the sensors connected to the capacitance measuring unit 32 may be measured.

In FIG. 3, the capacitance in the third sequence was measured to be larger than the capacitance in the other sequence. In this case, the coordinate measuring unit 34 receives the capacitance corresponding to each sequence measured by the capacitance measuring unit 32 and confirms that the capacitance of the third sequence is the maximum. After checking the coordinates of the switch connected in the third sequence, it may be determined that the x coordinate on the touch screen of the object is the coordinate of the third sequence. For example, when the switches x3 and x4 are connected in the third sequence, the coordinate measuring unit 34 may determine coordinates corresponding to the arithmetic mean of x3 and x4. The coordinates of the y-axis may also be determined in the same manner as the x-coordinate determination process of the object.

4 is a diagram comparing the capacitance of the x-axis sensor for each switch control sequence according to the z-axis distance of the object.

The z-axis is a coordinate axis perpendicular to the x-axis and y-axis, and is defined as a coordinate axis set perpendicular to the top of the touch screen surface. The z-axis coordinate of the object is measured by changing the value of the capacitance of the sensor constituting the sensor unit 11 according to the z-axis distance when the x, y coordinates of the object on the touch screen are the same. For example, when the object is located at the same x, y coordinates on the touch screen and positioned at a distance of z1 and z2, the capacitance of the sensor according to each switch control sequence may have a distribution as shown in FIG. 4. The closer the touch screen is, the more the capacitance of the sensor increases, so the object at z1 is located closer than the object at z2. According to an embodiment of the present invention, the relationship between the capacitance previously stored in the system and the z axis distance is The defined table can be used to calculate the z-axis coordinates of the object. According to another embodiment of the present invention, the z-axis coordinate may be measured as an area that is not a numerical result. For example, when located within 1cm on the touch screen, it may be measured in the near area, in the case of located within 1cm to 2cm in the mid-distance region, at a distance greater than the far region.

5 is a block diagram of a capacitive touch screen device using two or more capacitive measuring units according to an embodiment of the present invention.

As shown in FIG. 5, the capacitive touch screen device using two or more capacitive measuring units according to an embodiment of the present invention includes a sensor unit 11 including a plurality of sensors whose capacitance varies according to the approach of an object. ), A first capacitance measuring unit 32a measuring the capacitance of some of the plurality of sensors, a second capacitance measuring unit 32b measuring the capacitance of the remaining sensors except for some of the sensors, and the partial A first switch unit 31a for connecting a sensor to the first capacitance measuring unit 32a, a second switch unit 31b for connecting the remaining sensor to the second capacitance measuring unit 32b, and a switch control sequence. Accordingly, the first switch unit 31a and the second switch unit 31b are connected to the first capacitance measuring unit 32a and the second capacitance measuring unit 32b in various combinations. Switch control unit 33 for controlling, And a coordinate measuring section 34 for measuring three-dimensional coordinates of the proximity of the object to the measured capacitance of the switch, the switch control sequence and control sequence based.

Functions of the sensor unit 11, the switch control unit 33, and the coordinate calculation unit 34 are the same as those of FIG. 2.

According to an embodiment of the present invention, the first switch unit 31a is connected to the upper sensors of the sensor unit 11, and the second switch unit 31b is a lower sensor of the sensor unit 11. Can be connected to them. According to another embodiment of the present invention, the capacitance measuring units 32a and 32b may be configured in two or more, and the switch units 31a and 31b may also be configured in two or more. By configuring two or more of the capacitance measuring units 32a and 32b, the number of coordinates of the object that can be measured per unit time may increase. For example, as shown in FIG. 5, if the capacitance measuring unit is composed of two and each of the capacitance measuring units 32a and 32b is in charge of half of the sensors constituting the sensor unit 11, the same switch control sequence may be used. Capacitance measurements can be made twice as fast as with one capacitance measurement unit.

The merge switch 51 of FIG. 5 is used when measuring capacitance by merging an x-axis sensor and a y-axis sensor. For example, when measuring the capacitance of the sensor of FIG. 5A by combining an upper first sensor 17a and a lower first sensor 17b, the merge switch 51 is connected to the first capacitance measuring unit. The capacitance may be measured at 32a or at the second capacitance measuring unit 32b.

6 is a flowchart illustrating a method of detecting an object and measuring a coordinate of a capacitive touch screen according to an embodiment of the present invention.

As shown in FIG. 6, the object sensing and coordinate measuring method of the capacitive touch screen includes detecting a change in capacitance of a plurality of sensors constituting the sensor unit 11 when an object approaches (S61); Controlling the switch unit 11 to connect the plurality of sensors to the capacitive measurement unit 32 in various combinations according to a switch control sequence (S62), and interrupting some of the sensors according to a switch control sequence Connecting to the capacitance measuring unit 32 (S63), measuring the capacitance of the connected sensor (S64), determining whether the coordinate measurement of the object is possible (S65), the switch control sequence and the corresponding switch control And measuring (S66) three-dimensional coordinates of the approached object based on the measured capacitance for the sequence.

In the step S61, when a conductive object such as a finger approaches the touch screen, capacitances of the plurality of sensors constituting the sensor unit 11 are changed to detect the proximity of the object. In the capacitive touch screen, the capacitance of the sensor increases when the object approaches, and the increase increases as the distance approaches.

In the step S62, the switch controller 33 connects the plurality of sensors constituting the sensor unit 11 to the capacitance measuring unit 32 in various combinations according to a switch control sequence. The unit 11 is controlled.

According to an embodiment of the present invention, the switch control sequence initially connects only one sensor to the capacitance measuring unit 32, and if the object cannot be detected in the sequence, the two electrostatic sensors are detected. It is connected to the capacity measuring unit 32. According to another embodiment of the present invention, the switch control sequence may connect the two sensors from the beginning, the switch control sequence may be changed by the user of the system, or may be defined by software installed in the system. May be preset in the system. However, preferably, when the area of the sensor becomes larger than the size of the object, the object can be detected, but since it is difficult to measure the exact position of the object on the sensor, a small number to a large number of switches are connected.

In step S63, the switch unit 11 connects the plurality of sensors to the capacitance measuring unit 32 according to the switch control sequence. According to an embodiment of the present invention, the switch unit 11 measures the capacitance of the sensor connected to each of the switch control sequences by connecting the plurality of sensors to the capacitance measuring unit 32 by time division. Let the part 32 measure.

In another embodiment of the present invention, the capacitance measuring unit 32 is composed of at least two or more may increase the number of coordinates of the object that can be measured per unit time. For example, when the capacitance measuring unit is composed of two, the plurality of sensors may be half connected to the two capacitance measuring units 32a and 32b. In this case, the number of coordinates of the measurable object per unit time may be doubled as compared with the case of one capacitance measuring unit in the same switch control sequence.

In the step (S64), the capacitance measuring unit 32 measures the capacitance of the plurality of sensors connected. The capacitance measuring unit 32 may convert a change in capacitance of the sensor into a voltage change and measure the change.

In the step S65, it is determined whether the coordinate measurement of the object is possible. If the number of sensors connected to the capacitance measuring unit 32 is small and the area of the sensor is not large enough to detect the object, the measurement of the coordinates of the object is impossible. Therefore, in this case, returning to step S62, the switch control unit controls the switch unit in the next switch control sequence so that the switch unit connects more sensors to the capacitance measuring unit 32.

According to an embodiment of the present invention, the object detection method of the capacitive touch screen may dynamically merge the sensor to adjust the sensitivity and accuracy of the sensor. In addition, it is possible to detect an object located in the air of the touch screen, it is possible to measure the exact coordinates of the object by adjusting the area of the sensor only to the extent that the object can be detected.

In step S66, the coordinate measuring unit 34 measures the three-dimensional coordinates of the approached object based on the switch control sequence and the measured capacitance of the switch control sequence. The coordinate measuring unit 34 receives a capacitance of the sensors measured by the capacitance measuring unit 32 with respect to the switch control sequence, and extracts a sequence having a maximum capacitance. The x, y coordinates of the object may be measured by checking the coordinates of the sensor connected to the sequence. In addition, since the capacitance of the sensor changes according to the distance of the z-axis, the z-axis coordinates of the object may be measured using a table that defines a relationship between the capacitance previously stored in the system and the z-axis distance. According to another embodiment of the present invention, the z-axis coordinates may be measured in an area other than the numerical result.

Although the present invention has been described through the above embodiments, the above embodiments are merely intended to illustrate the spirit of the present invention, and the present invention is not limited thereto. Those skilled in the art will appreciate that various modifications may be made to the embodiments described above. The scope of the invention is defined only by the interpretation of the appended claims.

1A is an exemplary diagram of a capacitive dual layer touch screen according to an embodiment of the present invention.

1B and 1C are plan views of the upper ITO panel and the lower ITO panel constituting FIG. 1A.

FIG. 1D is a cross-sectional view of the AA ′ portion of FIG. 1A. FIG.

2 is a block diagram of a capacitive touch screen device according to an embodiment of the present invention.

3 is a diagram comparing capacitance of an x-axis sensor according to each switch control sequence.

4 is a diagram comparing the capacitance of the x-axis sensor for each switch control sequence according to the z-axis distance of the object.

5 is a block diagram of a capacitive touch screen device using two or more capacitive measuring units according to an embodiment of the present invention.

FIG. 5A is an exemplary diagram of a capacitive touch screen device when measuring the capacitance of the upper first sensor and the lower first sensor of FIG. 5 according to an embodiment of the present disclosure.

6 is a flowchart illustrating a method of detecting an object and measuring a coordinate of a capacitive touch screen according to an embodiment of the present invention.

Claims (8)

A sensor unit including a plurality of sensors whose capacitance varies according to the approach of an object; A capacitance measuring unit measuring the capacitance of the sensor; And A switch unit connecting the plurality of sensors to the capacitance measuring unit; Capacitive touch screen device comprising a. The method of claim 1, And a switch controller for controlling the switch unit to connect the plurality of sensors to the capacitance measuring unit in various combinations according to a switch control sequence. The method of claim 2, And a coordinate measuring unit configured to measure three-dimensional coordinates of the approached object based on the switch control sequence and the measured capacitance of the switch control sequence. The method of claim 3, wherein Capacitive touch screen device of at least two capacitive measuring unit. The method of claim 4, wherein In case of two capacitive measuring units, each capacitive measuring unit measures the capacitance in two directions perpendicular to each other with respect to the sensor unit. Detecting a change in capacitance of the plurality of sensors constituting the sensor unit when the object approaches; Connecting some of the sensors to a capacitance measurement unit according to a switch control sequence; And Measuring capacitance of the connected sensors; Object detection method of a capacitive touch screen comprising a. The method of claim 6, wherein the connecting step, And controlling a switch unit to connect the plurality of sensors to the capacitive measurement unit in various combinations according to the switch control sequence. The method of claim 7, wherein And measuring the three-dimensional coordinates of the approached object based on the switch control sequence and the measured capacitance for the switch control sequence.

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