KR20100127457A - Touch screen using infrared scanning - Google Patents

Abstract

PURPOSE: A touch screen device using an infrared scanning method is provided to increase accuracy of X/Y location detection without increasing the number of transmitting infrared LEDs and receiving photo transistors. CONSTITUTION: Infrared laser scanners(31,32) are installed in at least two edges of a screen to periodically scan the entire area of the screen. A light guide bar(33~35) is installed on the girth of the screen. Infrared receiving phototransistors(36,37) are installed in the end of the light guide bar. An X/Y decoder(13) calculates X/Y location information and size information of an object contacting a screen using light amount information of an infrared receiving phototransistor and laser beam angel information of the infrared laser scanner.

Description

Infrared Scanning Touch Screen Device {TOUCH SCREEN USING INFRARED SCANNING}

The present invention relates to a touch screen device using infrared rays, and more particularly, to a touch screen device including an infrared laser scanner, a light guide bar, an infrared receiving phototransistor, and an X / Y decoder.

In general, conventional methods for implementing a touch screen include a resistive film method, a capacitive method, an ultrasonic method, and an infrared matrix method. In addition, a number of methods, such as an image processing method, a piezo method, and a tension measurement method through a camera, have been proposed and commercialized.

Among these, an example of a conventional infrared matrix type touch screen will be described with reference to FIGS. 1 and 2.

1 is an exemplary diagram for describing a problem according to a multi-touch of a conventional infrared matrix type touch device, and FIG. 2 is a diagram illustrating a structure of a conventional infrared matrix type touch device.

As shown in FIG. 2, the infrared ray transmitting LED 11 and the infrared ray receiving phototransistor 12 are densely arranged up and down and left and right along the outline of the screen 10, and the infrared light is formed on the screen 10. When a matrix is formed and a certain part on the screen 10 is touched, infrared rays therein are blocked, so it is sensed and transmitted to the X / Y decoder 13 to know the X / Y position of the contacted object. That's how it works. In this method, since the infrared transmitting LED 11 and the infrared receiving phototransistor 12 are arranged in an array along the frame outside the screen, the front of the screen 10 does not need to be covered by the touch panel, thereby providing a clear screen. It has advantages, and it is relatively easy to cope with the enlargement of the screen, and has the advantage of operating regardless of the type of the object to be touched. .

The conventional infrared matrix method requires a large number of infrared LEDs and the same number of infrared phototransistors, and the number increases as the screen becomes larger, which is disadvantageous compared to other methods in terms of cost. In addition, since the positional resolution of the touch is determined by the number of LEDs and phototransistors, the cost problem arises again because the number of LEDs and phototransistors must be increased to increase the resolution.

In order to solve this problem of resolution, references 1 and 2 calculate X / Y position information by linear interpolation using the size information of light obtained from adjacent phototransistors affected when a touch is made. Attempts to improve positional accuracy. However, the size information of the light read from the phototransistor may vary depending on the brightness change or the temperature change of the environment, and may also vary depending on the light transmittance of the object in contact with the screen. The estimation method cannot guarantee accurate position accuracy.

Recently, even if two or more objects touch the screen, a multi-touch function that can recognize the picture has been important. Such a multi-touch function can provide a more intuitive and useful convenience to the user, such as zoom in, zoom out, and rotation of the screen. In the conventional infrared matrix method, since the shadow of the touch object caused by the LED light is read by the phototransistors on the opposite side, the information projected on the X and Y axes is multi-touch as shown in FIG. 1. If it happened, the touch position could not be determined. That is, when A touches the position A in FIG. 1, Ax and Ay are sensed to determine the position of the object A. If you touch the B position, Bx and By will be detected and you will know the position of B. Subsequently, when C or D is touched with the third touch point while A and B are touched, the touch cannot be detected. Since Ax, Ay and Bx, By are already used to touch A and B, the touch of C or D cannot be detected. Also, if B or D is touched while A and C are touched, the touch is detected but B and D cannot be distinguished.

As illustrated above, the conventional infrared matrix method using two X / Y axes cannot distinguish three or more multi-touches.

Accordingly, an object of the present invention is to provide an infrared scan type touch screen device that can increase the accuracy of X / Y position detection without increasing the number of the transmitting infrared LED and the receiving photo transistor in order to solve the above problems. It is done.

In addition, another object of the present invention is to provide a detection method for a multi-touch that can accurately detect each position even if three or more objects are touched at the same time.

An infrared scan type touch screen device of the present invention includes a screen on which a user can touch and view an image on or through the screen; Two or more infrared laser scanners installed at two or more edges of the screen to scan infrared the entire area of the screen at regular intervals; A light guide bar installed at an edge of the screen; An infrared reception phototransistor provided at an end of the light guide bar; An X / Y decoder for detecting X / Y coordinates; The X / Y decoder uses the information about the amount of light read from the infrared receiving phototransistor and the angle information of the laser beam read from the infrared laser scanner to obtain X / Y position information and size information of an object contacted on the screen. It is characterized by calculating.

In addition, the infrared laser scanner includes a motor; A mirror connected to the rotating shaft of the motor; An infrared laser emitted towards the mirror; And a rotation detector for detecting rotation of the motor.

Further, the light guide bar has a cylindrical or polygonal shape, and the mirror has a polygonal shape.

In addition, a screen that a user can touch and view an image on or through the screen; Two or more infrared laser scanners installed at two or more edges of the screen to scan infrared the entire area of the screen at regular intervals; A light guide bar installed at an edge of the screen and equipped with an infrared receiving phototransistor at regular intervals; An X / Y decoder for detecting X / Y coordinates; The X / Y decoder uses the information about the amount of light read from the infrared receiving phototransistor and the angle information of the laser beam read from the infrared laser scanner to obtain X / Y position information and size information of an object contacted on the screen. It is characterized by calculating.

As described above, the infrared scan type touch screen device according to the present invention uses an infrared laser scanner instead of the infrared LED array on the transmitting side, and guides instead of the phototransistor array on the receiving side, compared with the conventional infrared matrix method. By using bars and few phototransistors, there is an advantage that the number of components can be drastically reduced.

In addition, the infrared scan type touch screen device according to the present invention has an advantage in that the cost can be reduced because the size of the screen can be easily responded without increasing the parts.

In addition, the infrared scan type touch screen device according to the present invention has an advantage in that it is possible to provide a multi-touch function capable of detecting respective touch positions even when three or more objects are touched at the same time.

Hereinafter, an infrared scan type touch screen device according to the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to a client's or operator's intention or custom. Therefore, the definition should be based on the contents throughout this specification.

Like numbers refer to like elements throughout the drawings.

3 is a diagram showing the structure of an infrared scan type touch screen device according to the present invention. FIGS. 4 and 5 are diagrams showing an infrared laser scanner, and FIG. 6 is a diagram showing an infrared light propagating through a light guide bar. FIG. 7 is a diagram illustrating a coordinate detection method when two laser scanners are used, FIG. 8 is a diagram illustrating four laser scanners, and FIG. 9 is a light guide bar for supporting a large screen. It is a figure which shows the state which further arrange | positioned the infrared receiving phototransistor in the figure.

Referring to the configuration of the touch screen device of the infrared scanning method according to the present invention with reference to Figures 3 to 9, first, the infrared laser scanner (31, 32) for scanning the entire area of the screen 10 with an infrared laser beam It is provided. As shown in FIG. 4, the infrared laser scanners 31 and 32 include an ultra-compact motor 41 and a reflection mirror 43 connected to the shaft 42 of the motor 41, an infrared laser 44, and The rotation detector 45 of the motor 41 is provided. The infrared laser 44 emits a small spot beam to the mirror 43, and the spot beam reflected from the mirror 43 scans the entire screen 10 as the motor 41 rotates. In addition, the rotation detector 45 for detecting the rotation of the motor 41 generates a certain number of pulses per revolution of the motor 43, one pulse per revolution is sufficient for the implementation of the present invention. The mirror 43 is represented by a quadrilateral in this example, but in actual implementation, the mirror 43 may have any number of reflective surfaces, such as hexagonal and octagonal.

The infrared laser scanners 31 and 32 are installed at a height such that the laser scan beam of FIG. 3 can reach the light guide bars 33, 34 and 35 on the opposite side without contacting the surface of the screen 10. And the distance between the surface of the screen 10 and 5 to 10 mm. In addition, the infrared laser scanners 31 and 32 are installed at two or more corners of the screen 10, and at the same time, when four or more laser scanners are needed to distinguish many touch points, the upper, lower, left, right, middle, and middle portions of the screen 10 are separated. You can also extend the installation location to a point. The scan beam scans the infrared beam over the entire area of the screen 10 at regular intervals, the cycle of which is the number of revolutions of the motor 41 and the number of reflective surfaces of the mirror 43 (four, six, six ... ), And the scan period is typically set to dozens of scans per second.

In addition, the light guide bars 33, 34, and 35 are provided as a means for transmitting the scan beams arriving across the screen 10 to the infrared receiving phototransistors 36 and 37. Referring to FIG. 6, the light guides are provided. The form in which the infrared light propagates in the bars 33, 34, and 35 is shown in detail. In general, the material of the light guide bars 33, 34, and 35 is polymethylmethacrylate (PMMA) having good total reflection characteristics with respect to the infrared wavelength. The light guide bars 33, 34, 35 have a cylindrical shape or a rod shape having an arbitrary square shape, and can be easily machined and installed according to the size of the screen. 6 illustrates a process of propagating a scan beam when a rectangular light guide bar is used. FIG. 6A is a view from the side of the light guide bar, FIG. 6B is a view from the tip of the light guide bar, and FIG. 6C is a view of FIG. 6A rotated by 90 °. When the scan beam enters the light guide bar 33, 34, 35 at any angle through the incident surface 51, some light is scattered through scattering at the scattering surface 52 opposite to the incident surface 51. The total reflection surface 53 is reached. Part of the light reaching the total reflection surface 53 propagates to the tips of the light guide bars 33, 34, 35 through total internal reflection. The light guide bar may have various shapes and a light guiding method, and FIG. 6 is only an example of one embodiment for description.

Referring to the case where two laser scanners 31 and 32 are used as shown in FIG. 3, the operation of the infrared scan type touch screen device according to the present invention will be described. The light guide bar 33 or the light guide bar 34 is crossed across the screen 10 and sensed by the infrared receiving phototransistor 36 located at the tip through the internal reflection of the light guide bars 33 and 34. Scanning light emitted from the infrared laser scanner 32 crosses the screen 10 and reaches the light guide bar 33 or the light guide bar 35, and is reflected at the tip through the internal reflection of the light guide bars 33 and 35. It is detected by the infrared receiving phototransistor 37 located. In this case, in order to solve the interference problem in which the signal of the infrared laser scanner 31 is transmitted to the infrared receiving phototransistor 37 or the signal of the infrared laser scanner 32 is transmitted to the infrared receiving phototransistor 36, a frequency division method is used. However, a time division method can be used. In the frequency division method, the infrared laser scanners 31 and 32 emit scan light having different wavelengths, and the infrared receiving phototransistors 36 and 37 also have detection bands having different wavelengths. Light is detected only in the infrared receiving phototransistor 36 and the scan light of the infrared laser scanner 32 is detected only in the infrared receiving phototransistor 37. In addition, in the time division method, the interference problem may be solved by changing the laser emission times of the infrared laser scanners 31 and 32.

In this way, information on the size of the scan light detected by the infrared receiving phototransistors 36 and 37 is transmitted to the X / Y decoder 13. At the same time, the output of the rotation detector 45 of the infrared laser scanners 31 and 32, i.e., the rotation pulse, is also transmitted to the X / Y decoder 13, which time-divisions the interval of this rotation pulse. The rotation angle of the motor 41 is calculated. Since the motor 41 of the infrared laser scanners 31 and 32 rotates at a constant speed, it is possible to calculate the rotation angle by time-dividing the interval of the rotation pulse.

When a touch occurs on the screen 10, the amount of light transmitted to the X / Y decoder 13 decreases near the touch point. The X / Y decoder 13 has advance information on the amount of light when there is no touch. When a touch occurs, if the amount of light falls below the prior information, it is recognized that the touch occurs. Since the amount of light reaching the X / Y decoder 13 varies depending on the angle of the scan beam even when there is no touch due to the nature of the scheme of the present invention, the infrared beam is positioned at the position where the scan beam reaches the light guide bars 33, 34, 35. The farther the distance to the receiving phototransistors 36 and 37 is, the smaller the amount of light is. Therefore, the X / Y decoder 13 is arranged in advance in the form of an array in which the rotation angles of the infrared laser scanners 31 and 32 are indexed. Information will be kept.

Referring to FIG. 7, the touch position detection method in the infrared scan type touch screen device according to the present invention will be described in detail. When a touch is made at the position A, the light guide bar is sent out from the infrared laser scanner 31. The amount of light of the infrared receiving phototransistor 36 transmitted through the 33 is reduced, and the rotation angle of the motor 41 of the infrared laser scanner 31 at this moment is θ A1, and at the same time the infrared laser scanner 32 The amount of light of the infrared receiving phototransistor 37 transmitted from the light guide bar 35 is also reduced. When the rotation angle of the motor 41 of the infrared laser scanner 32 at this moment is θA2, the touch point A positioning problem,

Y = aX; Where a = tanθA1

Y = ly-bX; Here, it can be simplified to the problem of finding the intersection point of a straight line with b = tanθA2.

If the touch is made at the same time, the position of B is

Y = cX; Where a straight line with c = tanθB1

Y = ly-dX; Here, the intersection point of the straight line with d = tanθB2 can be obtained.

At this time, if the touch is made at the position of C at the same time, the touch of C cannot be detected, and if the touch of D is made, it cannot be distinguished from the touch of A and B. As a result, as in the infrared matrix method described above, the method of using two infrared laser scanners cannot distinguish three or more simultaneous touches.

In order to solve the problem of the multi-touch, Reference 3 uses a method of extending the detection axis on the plane to three or more in the capacitive method. However, as shown in FIGS. 1 and 2, the infrared matrix method cannot extend the detection axis beyond two axes in the X / Y direction.

FIG. 8 illustrates a form in which the infrared laser scanners used in the infrared scan type touch screen device according to the present invention are expanded to four. In FIG. 8, four infrared laser scanners 31, 32, 51, 52 were used and four infrared receiving phototransistors 36, 37, 38, 39 were used. In this way, four independent angles are assigned to one touch point, and as a result, the detection axis is extended to four, so that four simultaneous touch points can be recognized. If more simultaneous touch is required, the infrared laser scanner can be extended to be installed not only at the corners of the screen but also at the top, bottom, left and right middle points of the screen, thereby theoretically allowing infinite touch point recognition.

In FIG. 9, as the screen 10 is enlarged, the lengths of the light guide bars 33, 34, and 35 become longer, and thus, the infrared light receiving phototransistors 36 and 37 are transmitted through the light guide bars 33, 34, and 35. In the case where the amount of transmitted light becomes too small, a form in which the separate infrared receiving phototransistors 80, 81, 82, 83, 84 are extended in the middle of the light guide bars 33, 34, 35 is shown. In the conventional infrared matrix method, as the size of the screen 10 increases, the number of the infrared LEDs 11 and the infrared receiving phototransistors 12 should also increase in proportion thereto, whereas the infrared scan type touch screen according to the present invention. The method of the device requires only a slight increase in the number of infrared receiving phototransistors, which simplifies the structure and can provide great advantages in terms of cost.

As described above, the present invention has been described based on the preferred embodiments, but these embodiments are intended to illustrate the present invention, not to limit the present invention, so that those skilled in the art to which the present invention pertains can perform the above without departing from the technical spirit of the present invention. Various changes, modifications or adjustments to the example will be possible. Therefore, the protection scope of the present invention should be construed as including all changes, modifications or adjustments belonging to the gist of the technical idea of the present invention.

Reference 1: Measurement method of detailed coordinates and error correction method of touch panel

                (10-2006-0005932)

        2: Multipoint coordinate recognition method and contact area recognition method of infrared touch screen

                (10-2006-0095398)

        3: Capacitive sensor touch sensing electrode plate with multi-axis touch sensing line

          (10-2007-0079087)

1 is an exemplary view for explaining a problem according to the multi-touch of the conventional infrared matrix type touch device.

2 is a structural diagram of a conventional infrared matrix type touch device.

3 is a structural diagram of an infrared scan type touch screen device according to the present invention;

4 and 5 show an infrared laser scanner.

6 is a view showing a form in which infrared light propagates in the light guide bar.

7 is a diagram for explaining a coordinate detection method when using two laser scanners.

8 is a diagram showing a case where four laser scanners are used.

FIG. 9 is a view illustrating a state in which an infrared receiving phototransistor is further disposed inside a light guide bar for supporting a large screen; FIG.

Explanation of symbols on main parts of drawing

10: Screen 11: Infrared LED

12, 36. 37, 38, 39, 80, 81, 82, 83, 84: Infrared receiving phototransistor

13: X / Y decoder

31, 32, 51, 52: infrared laser scanner

33, 34, 35: Light guide bar 41: Motor

42: axis of rotation 43: mirror

44: infrared laser 45: rotation detector

Claims (4)

A screen that the user can touch and view the image on or through the screen; Two or more infrared laser scanners installed at two or more edges of the screen to scan infrared the entire area of the screen at regular intervals; A light guide bar installed at an edge of the screen; An infrared reception phototransistor provided at an end of the light guide bar; An X / Y decoder for detecting X / Y coordinates; The X / Y decoder uses the information about the amount of light read from the infrared receiving phototransistor and the angle information of the laser beam read from the infrared laser scanner to obtain X / Y position information and size information of an object contacted on the screen. Infrared scanning type touch screen device, characterized in that the calculation. The method of claim 1, wherein the infrared laser scanner, A motor; A mirror connected to the rotating shaft of the motor; An infrared laser emitted towards the mirror; Infrared scan type touch screen device, characterized in that consisting of a rotation detector for detecting the rotation of the motor. The touch screen device according to claim 1 or 2, wherein the light guide bar has a cylindrical or polygonal shape, and the mirror has a polygonal shape. A screen that the user can touch and view the image on or through the screen; Two or more infrared laser scanners installed at two or more edges of the screen to scan infrared the entire area of the screen at regular intervals; A light guide bar installed at an edge of the screen and equipped with an infrared receiving phototransistor at regular intervals; An X / Y decoder for detecting X / Y coordinates; The X / Y decoder uses the information about the amount of light read from the infrared receiving phototransistor and the angle information of the laser beam read from the infrared laser scanner to obtain X / Y position information and size information of an object contacted on the screen. Infrared scanning type touch screen device, characterized in that the calculation.

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