HK1153830B - Coordinate locating method and apparatus - Google Patents

Description

Coordinate positioning method and equipment

Technical Field

The present invention relates generally to a coordinate locating device and a coordinate locating method, and more particularly, to a coordinate locating device capable of locating coordinates of a plurality of objects and a coordinate locating method thereof.

Background

Various coordinate locating devices for locating the coordinates of an object are known. Some coordinate locating devices may detect the coordinates of an object from a pointing instrument (e.g., a pen, a fingertip, or a particular device used in conjunction with such devices). Thus, a user may input information with a pointing instrument.

Common techniques used in conventional coordinate locating devices for locating the coordinates of an object include mechanical buttons, crossed beams, surface acoustic waves, capacitive sensing, and resistive materials. Among these devices, the device using the cross beam is not limited by the size of the display panel, and thus is competitive in terms of cost.

For example, U.S. patent No. 4,820,050 to griffin discloses a solid-state optical position determining apparatus having an LED light source and an image sensor. However, the apparatus can locate only the coordinates of one object, resulting in a certain limitation of application.

Another example is the device disclosed by United states patent number 5,484,966 entitled "Sensing stylus position using single one-dimensional image sensor" of West root (Segen). The device utilizes two mirrors and an image sensor, but can only locate the coordinates of one object.

To solve the above-mentioned problems of the two conventional technologies, U.S. patent publication No. 2009/0,066,662 proposes a system capable of distinguishing a plurality of touch points, and U.S. patent publication No. 2008/0143682 also proposes a display device having a multi-touch recognition function. However, both of the above patent publications require at least three image sensors, which greatly increases the manufacturing cost.

To overcome the above disadvantages, U.S. patent application No. 12/700,598 provides a coordinate locating apparatus capable of locating coordinates of a plurality of objects by detecting mirror images of the objects using only two detectors and a mirror, thereby reducing manufacturing costs. However, the complexity of the calculation increases with the number of touch points to be located.

Disclosure of Invention

In view of the above, a coordinate locating apparatus is provided that has the ability to locate the coordinates of two or more objects, is less costly to manufacture than devices using conventional techniques, and reduces the complexity of the calculations.

In one aspect, a coordinate locating device for locating at least one touch point on a plane is provided. The coordinate locating apparatus comprises: a first detection unit including a first light emitting element and a first light receiving element, the first detection unit being arranged at a first position of the plane; a second detection unit including a second light emitting element and a second light receiving element, the second detection unit being arranged at a second position of the plane; a first optical element disposed along an edge of the plane for reflecting and retro-reflecting light from the first and the second light emitting elements; and second and third optical elements arranged along two edges of the plane for performing at least one of reflecting and retro-reflecting light from the first and second light emitting elements or light reflected from the first optical element, the two edges both being adjacent to an edge along which the first optical element is arranged, wherein the at least one touch point is located based on the detected intensity of light received by the first and second light receiving elements, and the detected intensity of light is compared to a first threshold value and a second threshold value.

In another aspect, a coordinate locating method for locating at least one touch point on a plane is provided. The method comprises the following steps: generating a plurality of first signals corresponding to intensities of light emitted by the first light-emitting element and detected by the first light-receiving element at different angles; generating a plurality of second signals corresponding to intensities of light emitted by the second light emitting element and detected by the second light receiving element at different angles; obtaining a plurality of first candidate touch points based on a comparison of the first signal to a first threshold and a second threshold; obtaining a plurality of second candidate touch points based on a comparison of the second signal to the first threshold and the second threshold; and locating the at least one touch point based on the overlap of the first and second candidate touch points.

These and other features, aspects, and embodiments are described below in the section entitled "detailed description of certain embodiments".

Drawings

Features, aspects, and embodiments are described in conjunction with the appended drawings, in which:

FIG. 1 is a schematic diagram showing a plan view of the structure of a coordinate positioning apparatus according to an embodiment;

FIG. 2 is a cross-sectional view of the coordinate locating apparatus taken along line AA' of FIG. 1;

fig. 3A is a diagram showing a relationship between the number of pixels in the detection unit implemented as an image sensor and a detection angle;

FIG. 3B is a schematic diagram of a conventional image sensor;

FIG. 3C is a schematic diagram of a conventional laser scanning unit;

FIG. 4 is a side view of a coordinate positioning apparatus in a preferred embodiment;

fig. 5A is a diagram illustrating an operation of the detection unit when there is a touch point;

FIG. 5B is a diagram illustrating the signals generated by the receiving elements of the detection unit;

FIG. 6A is a diagram illustrating the operation of the coordinate locating device when there are two touch points;

FIG. 6B is a diagram illustrating the signals generated by the receiving elements of the detection unit;

FIG. 6C is a diagram illustrating a signal generated by a receiving element of another detection unit;

FIG. 7A is a flow chart of a coordinate locating method in accordance with the preferred embodiments;

FIG. 7B is a diagram illustrating the location of a first candidate touch point;

FIG. 7C is a diagram illustrating the location of a second candidate touch point;

FIG. 8A is a diagram illustrating another operation of the coordinate locating device when there are two touch points;

FIG. 8B is a diagram illustrating the signals generated by the receiving elements of the detection unit;

FIG. 8C is a diagram illustrating a signal generated by a receiving element of another detection unit;

FIG. 9A is a flow chart of a coordinate locating method according to another preferred embodiment;

FIG. 9B is a diagram illustrating the location of a first candidate touch point according to another preferred embodiment; and

FIG. 9C is a diagram illustrating the location of a second candidate touch point according to another preferred embodiment.

Detailed Description

Fig. 1 is a schematic diagram showing a plan view of the structure of a coordinate positioning apparatus 100 according to an embodiment. FIG. 2 shows a cross-sectional view of coordinate locating apparatus 100 along line AA' in FIG. 1. The coordinate positioning apparatus 100 includes detection units 2 and 4; the optical elements 6, 8, 10 and 12 (which may be omitted) and a processing unit (not shown in the figure). The optical elements are arranged on a touch substrate of the coordinate positioning apparatus 100. Take fig. 2 as an example. The optical elements 6 and 12 are over a touch substrate 14.

Each of the detection units 2 and 4 includes a light emitting element and a light receiving element. The light emitting elements are used to emit light from different angles. The light receiving elements are used for receiving light from different angles and further generating signals based on the intensity of the light from different angles. When a pointing instrument (e.g., a pen, a fingertip, or a specific device) touches a touch substrate (or touch panel), light emitted toward a touch point is blocked. That is, the intensity of the signal corresponding to the direction indicating the touch point is removed. Therefore, the direction indicating the touch point can be detected by the light receiving element. Since both the detection units 2 and 4 detect a direction indicating a touch point, the position of the touch point can be determined by the intersection of the two determined directions.

In a preferred embodiment, the detection units 2 and 4 may be two laser scanning units, two image sensor units, or one laser scanning unit and one image sensor unit. Please refer to fig. 3A, which is a diagram showing the operation of the image sensor. Fig. 3A depicts the relationship between the number of pixels in a detection unit implemented as an image sensor and the detection angle. The image sensor has a plurality of pixels each configured so as to detect light intensity at a corresponding angle denoted "θ". Signals representing the intensity of light from different angles are generated based on the detection result of each pixel. Fig. 3B illustrates a schematic diagram of a conventional image sensor. As depicted, the image sensor includes an LED, an aperture stop, a lens, and a sensor for receiving light.

The operation of the laser scanning unit is different from that of the image sensor. Fig. 3C is a schematic diagram of a conventional laser scanning unit. The laser scanning unit includes a laser source, a beam splitter, a detector, and a MEMS mirror. The angle of the light emitted by the laser scanning unit can be changed by rotating the MEMS mirror. Since the laser scanning unit is a conventional technique, details of the operation of each component of the laser scanning unit are omitted. The application of different types of laser scanning units is also omitted here, as those skilled in the art can easily apply different types of laser scanning units to the present invention based on the general knowledge in this technical field.

Referring to FIGS. 1 and 4, FIG. 4 illustrates a side view of a preferred embodiment coordinate positioning apparatus 100. In fig. 4, optical element 6 includes two retroreflector layers 32 sandwiching a mirror layer 34. In a preferred embodiment, the optical element 6 is arranged along an edge opposite to the edge connected by the corners on which the detection units 2 and 4 are located, and the optical elements 8, 10 are retroreflectors and are arranged adjacent to the optical element 6. In another embodiment, the optical element 12 may be arranged at the edge opposite to the optical element 6, if necessary. The operation of the coordinate locating apparatus 100 of the preferred embodiment is depicted in FIG. 1. In FIG. 1, when a beam is emitted along path 22 from the detection unit 2 to the first optical element 6, a portion of the beam is retroreflected on path 24 by retroreflector 32, and a portion of the beam is reflected by mirror 34 along path 26 to optical element 10, and then retroreflected back along path 28 by the third optical element 10 to the image sensor. Note that the positions of the detection units 2 and 4 and the composition of the optical element 6 are not limited to the above preferred embodiment. For example, the detection cells may be placed anywhere along one edge of the plane. The optical element 6 may comprise a layer of retroreflectors and a layer of mirrors, or the optical element 6 may comprise a plurality of retroreflectors and a plurality of mirrors arranged alternately. All optical elements have at least one retroreflector and at least one mirror capable of reflecting and retroreflecting light, and thus can function as the optical element 6.

Referring to fig. 5A and 5B, fig. 5A illustrates the operation of the detecting unit 2 when there is a touch point. Fig. 5B illustrates the signals generated by the receiving elements of the detection unit 2. When a pointing instrument (e.g., a pen, a fingertip, or a specific device) touches the touch point 50, it is at an angle θ₁₁The emitted light is blocked at the touch point. Thus, in 5B, the angle θ is shown₁₁Signal S of received light intensity₁₁Approximately zero. About at an angle theta₁₂Emitted light, a portion of the energy of which is reflected by the retroreflector of the optical element 6 to the detection unit 2, and the remaining energy is reflected by the mirror of the optical element 6 and then blocked at the point of touch. Thus, in FIG. 5B, the angle θ is shown₁₂Signal S of received light intensity₁₂Is between the magnitude of the signal S₁₁Between the magnitude of the other signals. In the preferred embodiment, two thresholds, Vth1 and Vth2, are used to classify the signals. If the intensity of a signal corresponding to a certain direction is lower than the threshold Vth2, it is determined that a real object is detected in the direction. If the intensity of the signal corresponding to a certain direction is lower than the threshold Vth1 but higher than the threshold Vth2, it is determined that an image of an object is detected in the direction. In fig. 5B, when the detection unit 2 is an image sensor, the x-axis of the graph indicates the number of pixels of the image sensor. Each pixel is configured so as to detect light intensity at a corresponding angle denoted "θ". That is, signals representing the intensities of light from different angles in fig. 5 are generated based on the detection result of each pixel. Such asIf the detection unit 2 is a laser scanning unit, the x-axis of the graph in FIG. 5B will change to represent time (not shown). Since the scanning speed of the laser scanner is predetermined, the intensities of light from different angles are obtained according to the time point at which the signal is detected and the predetermined scanning speed.

Please refer to fig. 6A, 6B and 6C. FIG. 6A illustrates the operation of the coordinate locating device 100 when there are two touch points. Fig. 6B illustrates the signals generated by the receiving elements of the detection unit 2. Fig. 6C illustrates the signals generated by the receiving elements of the detection unit 4. It can be seen that in the detection unit 2, the signal S₁₁Meaning that the object at touch point B is detected; signal S₁₂Meaning that an object at touch point a is detected; signal S₁₃Meaning that an image of the object on B' is detected; and S₁₄Meaning that an image of the object on a' is detected. With respect to the detection unit 4, the signal S₂₁Meaning that an object at touch point a is detected; signal S₂₂Meaning that the object at touch point B is detected; signal S₂₃Means that an image of the object on a' is detected; and signal S₂₄Meaning that an image of the object on B' is detected.

FIG. 7A illustrates a flow chart of a coordinate locating method of the preferred embodiment. When signals are generated by the sensing units 2 and 4, the processing units electrically connected to the sensing units 2 and 4 compare each signal to the thresholds Vth1 and Vth2 (step 702). Signals having an intensity below the threshold Vth2 are classified into a first group, and signals having an intensity below the threshold Vth1 and greater than the threshold Vth2 are classified into a second group (step 704). The signals in the first group indicate that a real object is detected at an angle represented by the signals. The signals in the second group indicate that an image of the object is detected at the angle represented by the signal.

In fig. 7A, after the grouping step, a plurality of first candidate touch points 72, 74, 76, and 78 are obtained based on the signal generated by the detection unit 2 (step 706). Please refer to fig. 7B. Signals in the first group having an intensity below the threshold Vth2 may be used to determine the optical path L₁₁To L₁₂. Optical path L₁₁To L₁₂Is a substantially straight line and is the path of light that is directly blocked by an object at the point of touch. Signals in the second group having intensities below the threshold Vth1 and above the threshold Vth2 may be used to determine the optical path M₁₃To M₁₄. Optical path M₁₃To M₁₄To the path of the light emitted from the detection unit 2, then reflected by the mirror of the optical element 6 and finally blocked by the object. Optical path L₁₁To L₁₂And the optical path M₁₃To M₁₄Are determined as first candidate touch points 72, 74, 76, and 78.

In the same way, a plurality of second candidate touch points 74, 78, 82, and 84 may be obtained based on the signal generated by the detection unit 4 (step 708). After determining the first candidate touch points 72, 74, 76, and 78 and the second candidate touch points 82, 74, 86, 78, touch points A and B may be determined by the overlaps 74 and 78 of the first candidate touch points 72, 74, 76, and 78 and the second candidate touch points 74, 78, 82, and 84 (step 710).

However, under certain conditions, the above method cannot locate all existing touch points. Please refer to fig. 8A, 8B and 8C. In fig. 8A, four paths may be determined based on the signal generated by the detection unit 2 (as in fig. 6A). However, as shown in fig. 8C, only three paths can be determined based on the signal generated by the detection unit 4 because the reflection path reaching the touch point a is in the shadow of the touch point B when viewed from the detection unit 4.

To overcome the problems mentioned above, another preferred embodiment of the coordinate locating method of the present invention is provided in FIG. 9A. Steps 902, 904, 906, 908, and 910 in fig. 9A are the same as steps 702, 704, 706, 708, and 710 in fig. 7A. After performing the first five steps, if only one touch point is located after the overlap determination (step 912), the method in fig. 9A further compares the number of candidate touch points generated from the signal of the detection unit 2 with the number of candidate touch points generated from the signal of the detection unit 4 (step 914). If the numbers are different, then the candidate touch point opposite the located touch point is selected as another touch point (step 916). As depicted in fig. 9B and 9C, the overlap of the first candidate touch points 92, 94, 96, and 98 and the second candidate touch points 91 and 98 is the candidate touch point 98. Thus, the candidate touch point 94 opposite the candidate touch point 98 is selected as another touch point.

The coordinate locating apparatus in the present invention can locate the coordinates of a plurality of objects by using only two detectors and an optical element capable of retro-reflecting and reflecting light to detect mirror images of the objects, compared to the conventional art requiring the use of three or more detectors, and thus is less costly to manufacture. Furthermore, the signal corresponding to the object is distinguished from the signal corresponding to the image of the object by means of two thresholds, since the optical element has at least one retroreflector and at least one mirror. The computational complexity is significantly reduced compared to U.S. patent application No. 12/700,598. In other words, faster touch response speed and lower computing hardware cost are achieved.

Although in the preferred embodiment mentioned above the optical elements 8, 10 and 12 are retroreflectors and the optical element 6 has two retroreflectors 32 and a mirror 34, the arrangement of the optical elements is not limited by the preferred embodiment. For example, in another embodiment, optical elements 8 and 10 may be retroreflectors, mirrors, or a combination thereof, and each of optical elements 6 and 12 has at least one retroreflector and at least one mirror; in another embodiment, optical elements 6 and 8 may be retroreflectors, mirrors, or a combination thereof, and each of optical elements 10 and 12 has at least one retroreflector and at least one mirror. Since a person having ordinary knowledge in the art can derive the appropriate threshold values depending on the arrangement of the optical elements, the details of the above-mentioned embodiments can be derived from the disclosure of the specification of the present application.

While some embodiments have been described above, it will be understood that the described embodiments are only examples. Accordingly, the devices and methods disclosed herein should not be limited to the specific embodiments, and should be construed based on the appended claims in conjunction with the foregoing description and accompanying drawings.

Claims (19)

1. Coordinate locating device for locating at least one touch point on a plane, characterized in that it comprises at least:

a first detection unit including a first light emitting element and a first light receiving element, the light being emitted by the first light emitting element and the light being detected by the first light receiving element at different angles, the first detection unit being arranged at a first position on an edge of the plane;

a second detection unit including a second light emitting element and a second light receiving element, the light being emitted by the second light emitting element and the light being detected by the second light receiving element at different angles, the second detection unit being arranged at a second position on an edge of the plane;

a first optical element disposed along an edge of the plane for reflecting and retro-reflecting light from the first and the second light emitting elements; and

second and third optical elements arranged along two edges of the plane for performing at least one of reflecting and retro-reflecting light from the first and the second light emitting elements or light reflected from the first optical element, the two edges both being adjacent to the edge along which the first optical element is arranged,

wherein the at least one touch point is located based on a detected intensity of light received by the first and the second light receiving elements and the detected intensity of light is compared with a first threshold and a second threshold,

a plurality of first candidate touch points and a plurality of second candidate touch points are obtained based on the first and second thresholds, respectively, and the at least one touch point is located based on an overlap of the first and second candidate touch points.

2. A coordinate positioning apparatus according to claim 1 wherein the first location is at a first corner of the plane.

3. A coordinate positioning apparatus according to claim 1 wherein the second location is at a second corner of the plane.

4. A coordinate positioning apparatus according to claim 1 wherein the first optical element is arranged along an edge opposite to the edge connected by the first and second locations.

5. A coordinate positioning apparatus according to claim 4 wherein a fourth optical element is arranged on the edge connected by the first and the second locations.

6. The coordinate positioning apparatus of claim 1 further comprising a processing unit electrically connected to the first and second detection units, wherein the processing unit determines that a real object is detected when the detected intensity of light is below the second threshold and determines that an image of the object is detected when the detected intensity of light is below the first threshold and above the second threshold.

7. The coordinate positioning apparatus of claim 1 wherein the first optical element comprises a retroreflector to retroreflect light and a mirror to reflect light.

8. The coordinate positioning apparatus of claim 1 wherein the second optical element and the third optical element are retroreflectors, mirrors, or combinations thereof.

9. The coordinate positioning apparatus of claim 1 wherein the first and second detection units are laser scanning units, image sensor units, or a combination thereof.

10. A coordinate locating method for locating at least one touch point on a plane, the method comprising at least:

generating a plurality of first signals corresponding to intensities of light emitted by the first light-emitting element and detected by the first light-receiving element at different angles;

generating a plurality of second signals corresponding to intensities of light emitted by the second light emitting element and detected by the second light receiving element at different angles;

obtaining a plurality of first candidate touch points based on a comparison of the first signal to a first threshold and a second threshold;

obtaining a plurality of second candidate touch points based on a comparison of the second signal to the first threshold and the second threshold; and

locating the at least one touch point based on an overlap of the first and second candidate touch points.

11. The coordinate positioning method of claim 10, wherein the step of generating the plurality of first signals comprises:

emitting light from different angles with the first light emitting element;

receiving light from different angles with the first light receiving element; and

generating the plurality of first signals with the first light receiving element based on intensities of light from different angles.

12. The coordinate positioning method of claim 10, wherein the step of generating the plurality of second signals comprises:

emitting light from different angles with the second light emitting element;

receiving light from different angles with the second light receiving element; and

generating the plurality of second signals with the second light receiving element based on intensities of light from different angles.

13. The coordinate positioning method of claim 10, wherein the step of obtaining the plurality of first candidate touch points comprises:

comparing each of the plurality of first signals to the first threshold and the second threshold;

dividing the plurality of first signals into two groups, wherein first signals having an intensity below the second threshold are divided into a first group and first signals having an intensity below the first threshold but above the second threshold are divided into a second group;

obtaining a plurality of first optical paths of the first signals in the first group;

obtaining a plurality of second optical paths of the first signals in the second group; and

obtaining intersections of the plurality of first optical paths and the plurality of second optical paths as the plurality of first candidate touch points.

14. The coordinate positioning method of claim 10, wherein the step of obtaining the second plurality of candidate touch points comprises:

comparing each of the plurality of second signals to the first threshold and the second threshold;

dividing the plurality of second signals into two groups, wherein second signals having an intensity below the second threshold are divided into a first group, and second signals having an intensity below the first threshold but above the second threshold are divided into a second group;

obtaining a plurality of first optical paths of the second signals in the first group;

obtaining a plurality of second optical paths of the second signals in the second group; and

obtaining intersections of the plurality of first optical paths and the plurality of second optical paths as the plurality of second candidate touch points.

15. The coordinate positioning method of claim 13, wherein the plurality of first optical paths are light rays emitted from a first light emitting element.

16. The coordinate positioning method of claim 14, wherein the plurality of first optical paths are light rays emitted from a second light emitting element.

17. The coordinate positioning method of claim 13, wherein the plurality of second optical paths are reflected by a first optical element, and the first optical element reflects and retroreflects the light emitted from the first and the second light emitting elements.

18. The coordinate positioning method of claim 14 wherein the plurality of second optical paths are reflected by a first optical element, and the first optical element reflects and retroreflects the light emitted from the first and second light emitting elements.

19. The coordinate locating method according to claim 10, wherein if only one touch point is located and the number of the plurality of first candidate touch points is different from the number of the plurality of second candidate touch points, one of the first and second candidate touch points opposite to the located touch point is selected as the other touch point.