TWI436254B - Optical touch display system - Google Patents

Description

Optical touch screen system

The present invention relates to an optical touch screen system, and more particularly to an optical touch screen system suitable for multi-touch.

Today's touch screen technology has been widely used in a variety of electronic products, such as automated teller machines, handheld electronic devices and displays. In general, touch screen technology can be divided into three types: resistive, capacitive, and optical. Among them, the resistive and capacitive touch screen technology utilizes an object contact sensing device to cause an electric field change on the surface of the touch screen to position the object. The optical touch screen technology uses the object to move on the touch screen surface, causing the light path to block or the light and shadow to change and position the object.

Since the optical touch screen technology does not require special processes and components in the production process of the display device, and the cost of the optical touch technology is not affected by the size, the optical touch screen is on the medium and large screen. Production costs are lower than resistive and capacitive touch screens. In order to achieve the thinness of the design of the mechanism, the optical touch technology often places the image sensor at the corner of the touch screen and estimates the coordinates of the contact from different angles. However, for two or more contacts, the image tends to reduce the accuracy of the coordinate estimation or get the wrong coordinates (ghost) due to the shielding, which causes inconvenience in application.

The invention provides an optical touch screen system. The optical touch screen system includes a light-emitting component disposed around a touch area, and the light-emitting component is at least partially located above the touch area, such that light emitted by the light-emitting element can span the touch area; a mirror disposed around the touch area to reflect light emitted by the light emitting element and to generate a mirror image of the touch area; an image sensor disposed above the light emitting element and receiving a group located in the touch area a contact point and the mirror, the light of the light-emitting element is reflected, and a two-dimensional image is generated according to the image; wherein the two-dimensional image comprises a group of objects, the group image comprising a group of real images corresponding to the set of contact points And the light reflected by the mirror reflecting the light-emitting element generates a virtual image corresponding to the set of contact points; and a processing device for generating a position corresponding to the set of contact points according to the position of the set of real images in the two-dimensional image One group of output coordinates.

The invention further provides an optical touch screen system. The optical touch screen system includes a touch area; a light emitting element is disposed around a touch area, and the light emitting element is at least partially located above the touch area, such that light emitted by the light emitting element can span the touch An image sensor is disposed above the light emitting element to receive light reflected by the contact point of a group of the touch area and to generate a two-dimensional image; wherein the two-dimensional image comprises Corresponding to a group object image of the group of contact points; a distance measuring device connecting the light emitting element and the image sensor for controlling the light emitting element and the image sensor, and according to the group image in the second a coordinate in a first direction of the dimensional image, generating a group image distance corresponding to the group of objects; an angle measuring device connected to the image sensor for the 2D image according to the group image a coordinate in a second direction, generating a group image angle corresponding to the group image; and a processing device generating a corresponding contact point according to the group image distance and the group image angle One Output coordinates.

The invention further provides an optical touch screen system. The optical touch screen system includes a light-emitting component disposed around a touch area, and the light-emitting component is at least partially located above the touch area, such that light emitted by the light-emitting element can span the touch area; An image sensor is disposed above the light emitting element, and receives light reflected by the group of contact points of the touch area to reflect the light emitting element, and accordingly generates a first two-dimensional image; wherein the first two-dimensional image Included in the first group of real images corresponding to the set of contact points; a second image sensor disposed around the touch area, receiving the set of contact points located in the touch area to reflect the light of the light emitting element And generating a second two-dimensional image; wherein the second two-dimensional image includes a second group of real images corresponding to one of the set of contact points; and a distance measuring device connecting the light-emitting element and the first image sensor And controlling the first image sensor and the light emitting component, and generating a first one corresponding to the first group of real images according to coordinates of the first set of real images in a first direction in the two-dimensional image group And a processing device configured to generate a first set of real image lines according to the positions of the first group of real images and the first image sensor in the first two-dimensional image, and according to the second group of real images And generating a second set of real image lines at a position of the second image sensor in the second two-dimensional image, the processing device generating a corresponding line according to the first set of real image lines and the first set of real image lines A group of candidate points of the set of contact points, and according to the set of candidate coordinates and the first group of object distances, generating a group output coordinate corresponding to the set of contact points.

Please refer to Figure 1. 1 is a schematic diagram of an optical touchscreen system 100 in accordance with a first embodiment of the present invention. The optical touch screen system 100 includes an image sensor 101 , a light emitting element 102 , a touch area 103 , a light absorbing element 104 , and a processing device 120 . The processing device 120 includes a distance measuring device 105, an angle measuring device 106, and a processor 107. The optical touchscreen system 100 can detect multiple touch points. In addition, the distance measuring device 105 further controls the image sensor 101 and the light emitting element 102 through the control signal S _C . In Fig. 1, only two contact points O ₁ , O ₂ are drawn for convenience of explanation. In addition, the relative positions of the components in FIG. 1 are different from the actual settings for convenience of explanation, and the optical touch screen system 100 actually sets a lens LN on the sensing surface of the image sensor 101. So that all the light incident on the image sensor 101 passes through the lens LN, but the lens LN is not drawn in the first figure for convenience of explanation.

Preferably, the touch area 103 is set to a rectangular shape, and the light absorbing element 104 is disposed around the touch area 103 for absorbing the light of the light emitting element 102 to prevent the light of the light emitting element 102 from being reflected back to the image sensor 101. However, the touch area 103 can also be set as a trapezoid or other polygons according to user requirements. The light-emitting element 102 is disposed around the touch area 103. Preferably, a portion of the light-emitting element 102 is disposed above a corner of the touch area 103 such that light emitted by the light-emitting element 102 can traverse the touch area 103. The image sensor 101 is disposed adjacent to the light emitting element 102; preferably, the image sensor 101 is disposed above the light emitting element 102. In addition, the light-emitting element 102 can be a two-dimensional light source, including a line source and a light source conversion device, wherein the line source generates light through a laser diode or a light-emitting diode; the light source conversion device is the line The light source is converted into the two-dimensional light source to generate light that is incident on the touch area 103. The light source conversion device is a cylindrical mirror, a diffractive optical element (DOE) or a microelectromechanical mirror module.

The image sensor 101 is formed by one row of N rows of sensing units, and generates a two-dimensional image F having a resolution of M rows and N columns. More specifically, the two-dimensional image F uses a rectangular coordinate, and has M resolutions in the X-axis direction and N resolutions in the Y-axis direction.

The present invention uses a polar coordinate system in the touch area 103. As shown in FIG. 1, the origin (0, 0) of the polar coordinate system is disposed at the upper left corner of the touch area 103, and the angle reference is set to the upper boundary of the touch area 103. Preferably, the image sensor 101 is disposed at the upper left corner of the touch area, that is, the coordinates of the image sensor 101 are also the origin (0, 0); the light-emitting element 102 is also disposed at the upper left corner of the touch area. That is, the coordinates of the light-emitting element 102 are also the origin (0, 0). Therefore, the position of the object in the touch area 103 is represented by the angle θ from the upper left corner of the touch area 103 and the upper boundary.

The distance measuring device 105 and the angle measuring device 106 measure the object image distance of the contact point and the object image angle based on the object image position generated in the two-dimensional image F according to the light reflected by the contact point. More specifically, the distance measuring device 105 calculates the distance of the contact point based on the object image position in the Y-axis direction in the two-dimensional image F; the angle measuring device 106 is based on the X-axis direction in the two-dimensional image F. The object image position, the angle of the contact point is calculated. The processing device 107 then outputs the position (distance and angle) of the contact point based on the information obtained by the distance measuring device 105 and the angle measuring device 106.

Please refer to Figure 2. Figure 2 is a schematic diagram showing the optical touch screen system 100 during the calibration phase. Before the optical touch screen system 100 begins to detect the position of the contact point, a correction phase can be passed. The mode of operation of the optical touchscreen system 100 of the present invention during the calibration phase will be described below. Similarly, for convenience of explanation, the lens LN is not drawn in the second drawing.

In the correction phase, the calibrators P ₁ , P ₂ , P ₃ , and P ₄ may be disposed at each corner of the touch area 103, and the corresponding coordinates are (R _P1 , θ _P1 ), (R _P2 , θ _P2 ), (R _P3 , θ _P3 ), (R _P4 , θ _P4 ). The light-emitting elements 102 emit light to the calibrators P ₁ , P ₂ , P ₃ , and P _{4 , respectively} ; and the calibrators P ₁ , P ₂ , P ₃ , and P ₄ reflect the light emitted from the light-emitting elements 102 back to the image sensor 101. It is assumed here that the calibrators P ₁ , P ₂ , P ₃ , P ₄ are respectively imaged in the sensing units CS _{(M, 0)} , CS _{(M, N)} , CS _{(0, N)} , CS _{(0, 0)} ( This assumption is for convenience only and is different from the actual situation). That is to say, the coordinates of the corresponding objects P ₁ , P ₂ , P ₃ , and P ₄ in the two-dimensional image F are (M, 0), (M, respectively, the coordinates of the objects I _P1 , I _P2 , I _P3 , and I _P4 . , N), (0, N), (0, 0). Since the calibrators P ₁ -P _{4 are} disposed at each corner of the touch area, and the length and width of the touch area 103 are known, when the origin (0, 0) is set at the upper left corner of the touch area, the single It is mathematically derived (R _P1 , θ _P1 ), (R _P2 , θ _P2 ), (R _P3 , θ _P3 ), (R _P4 , θ _P4 ). For example, if the length of the touch region 103 is R _L and the width is W _L , then (R _P1 , θ _P1 ), (R _P2 , θ _P2 ), (R _P3 , θ _P3 ), ( R _P4 , θ _P4 ) are (0,0), (R _L ,0), ((R _L ² +W _L ² ) ^1/2 , tan ^-1 (W _L /R _L )), (W _L , 90°). In this way, in the case of the calibrators P ₃ and P ₄ , the distance measuring device 105 can know that when the phase difference N in the Y-axis direction in the two-dimensional image F, the actual distance difference is W _L and is interpolated. It is presumed that the position of an object image in the Y-axis direction in the two-dimensional image F corresponds to the distance from the origin in the touch region 103. In the case of the calibrators P ₁ and P ₃ , the angle measuring device 106 can know that when the phase difference M is in the X-axis direction in the two-dimensional image F, the actual angle difference is 90°, and an object image is estimated by interpolation. The position in the X-axis direction in the two-dimensional image F corresponds to the angle with the origin in the touch region 103. In addition, the above-mentioned correction method can be changed according to the needs of the user, such as changing the position and quantity of the calibration object, and the like.

Please refer to Figure 3. Figure 3 is a schematic diagram showing the optical touch screen system 100 of the present invention in normal operation. When in normal operation, a contact point of the light emitting element 102 emits light O _1; contact point O ₁ to the light emitting element 102 is reflected back out the light from the image sensor 101, and the photosensitive member to CS _{(X1, Y1)} on the image. That is to say, the coordinates of the corresponding object image I _O1 of the contact point O ₁ in the two-dimensional image F are (X ₁ , Y ₁ ). Since the distance measuring device 105 and the angle measuring device 106 know the coordinate relationship between the touch region 103 and the two-dimensional image F after the correction phase, the position of the contact point O ₁ in the touch region 103 can be calculated as ( R _O1 , θ _O1 ). The manner of calculating the contact point O ₂ is similar to the contact point O ₁ and will not be described here.

Please refer to Figure 4. FIG. 4 is a side view of the optical touch screen system 100. Fig. 4 is mainly used to explain the manner in which the distance measuring device 105 measures the distance R, and uses the calibrators P ₁ , P ₂ and the contact point O _T as an example. In addition, the lens LN is drawn in FIG. 4 to show that all of the light incident on the image sensor 101 passes through the lens LN, so that the image forming position is as shown in FIG. It is assumed that the distance R _L between the calibrators P ₁ and P ₂ is known, and the corresponding object images I _P1 and I _{P2 are} imaged in the two-dimensional image F, and their coordinates are (M, N) and (M, 0), respectively. At this time, the distance measuring device 105 detects the distance O _{OT of the} contact point O _T , and can use the object image I _OT in the two-dimensional image F in the Y-axis direction with respect to the positions of the object images I _P1 and I _P2 . Out. More specifically, the position of the object image I _OT is (X _T , Y _T ), so the distance R _OT can be obtained by the following equation: R _OT = (Y _T /N) × R _L .

Please refer to Figure 5. Figure 5 is a top view of the optical touch screen system 100. Fig. 5 is mainly used to explain the manner in which the angle measuring device 106 measures the angle θ, and uses the calibrators P ₂ , P ₃ for illustrative purposes. Since the angle θ _{P3 of the} calibrators P ₂ and P ₃ (such as tan ^-1 (W _L /R _L )) is known, and the corresponding objects like I _P2 and I _{P3 are} imaged at (M, N), (0, N). At this time, the angle measuring device 106 can detect the angle θ _{OT of the} contact point O _T by using the object image I _OT in the two-dimensional image F in the X-axis direction, compared with the positions of the object images I _P2 and I _P3 . Come to draw. More specifically, the position of the object image I _OT is (X _T , Y _T ), so the angle θ _OT can be obtained by the following equation: θ _OT = (X _T / M) × θ _P3 .

Please refer to Figure 6. Figure 6 is a schematic illustration of an optical touch screen system 600 in accordance with a second embodiment of the present invention. Compared with the optical touch screen system 100, the optical touch screen system 600 is provided with a mirror (reflecting element) 108, which is mainly used to improve the accuracy of determining the position of the contact point. In addition, the processing device 120 of the optical touch screen system 600 can optionally include a real image determining device 170. In the following description, it is assumed that the judgment of whether the object image in the two-dimensional image F is a real image is known. In addition, the relationship between the position of an object in the touch area and the position of the corresponding object image in the two-dimensional image according to the foregoing description should be deduced by those having ordinary knowledge in the art. Therefore, for convenience of explanation, the following mainly describes the position of the object in the touch area.

Please refer to Figure 7. Figure 7 is a flow chart illustrating the position of the optical touch screen system 600 to detect contact points. For convenience of explanation, only the case of the two contact points O ₁ and O ₂ will be described. In addition, the steps disclosed in FIG. 7 can be clearly explained for convenience of the related drawings, and may not actually be performed in accordance with the flow disclosed in FIG. The steps are as follows:

Step 701: The light-emitting element 102 emits light, and generates object images I _O1 , I _O2 , I _O1J , I _O2J on the two-dimensional image F via the contact points O ₁ and O ₂ and the reflection of the mirror, wherein I _O1J and I _O2J Corresponding to the mirror image (virtual image) of the contact points O ₁ and O ₂ respectively; please refer to FIG. 8 correspondingly; in FIG. 8 , the dotted line area represents the mirror image caused by the mirror 108 reflecting the light-emitting element 102 , wherein the touch point O ₁ , The corresponding mirrors of O ₂ are O _1J and O _2J . Therefore, the image sensor 101 will see four objects like I _O1 , I _O2 , I _O1J and I _O2J , where O _1J and O _2J are virtual images, as shown by the two-dimensional image F in FIG. 8 .

Step 702: The angle measuring device 106 generates the object image angles θ _O1 , θ _O2 , θ _O1J , θ _O2J according to the positions of the object images I _O1 , I _O2 , I _O1J , I _O2J in the X-axis direction of the two-dimensional image F; Please refer to Figure 9A for reference.

Step 703: The processing device 107 uses the light-emitting elements 102 as a starting point to generate real image lines SL _O1 and SL _O2 and virtual image lines SL _O1J and SL _O2J according to the object image angles θ _O1 , θ _O2 , θ _O1J , θ _O2J , _respectively ; Refer to Figure 9B.

Step 704: the processing means 107 calculates a straight line _SL O1J virtual image _S LO2J intersection with the plane in which the mirror 108 is G _1, G _2, image processing apparatus 107 to the image sensor 101 _J 101 (or a light emitting element 102 The mirror image 102 _J ), the intersection points G ₁ , G ₂ , and the virtual image lines SL _G1 and SL _{G2 are} generated; please refer to FIG. 10 .

Step 705: The processing device 107 calculates the real image lines SL _O1 , SL _O2 and the virtual image lines SL _G1 , SL _G2 , and generates four candidate coordinates O _C1 , O _C2 , O _C3 and O _C4 ; please refer to FIG. 11 . .

Step 706: The distance measuring device 105 generates the object image distances R _O1 and R _O2 according to the object images I _O1 and I _O2 at the position of the two-dimensional image F in the Y-axis direction; please refer to FIG. 12A.

Step 707: The processing device 107 selects the candidate coordinates with the smallest error between the real image line SL _O1 and the object image distance R _O1 as the coordinates of the last output contact point O ₁ ; please refer to FIG. 12B; the processing device 107 selects the real image. on a straight line with the object image SL _O2 minimum error distance R _O2 candidate coordinates as the coordinates of the contact point of the final output of the O _2; please refer to Figure 12 corresponding to B.

As can be seen from the above, the optical touch screen system 600 can first measure the object image angle through the image sensor 101 and the mirror 108, and then determine the coordinate with the smallest error among the candidate coordinates according to the distance measured by the distance measuring device 105. Take the output coordinates as the last point of contact.

In addition, the object image distance measured by the distance measuring device 105 is only used in steps 707 and 708 to determine which of the candidate coordinates is the output coordinate, so the accuracy of the measured object image distance need not be too high. In fact, the output coordinates of the contact point are still determined by the calculation of the processing device 107 from the measured angle.

In addition, the real image determining device 170 determines that the object image on the image sensor 101 corresponds to the real image or the virtual image in the touch region. More specifically, the real image determining means 170 determines whether the object image X is a real image based on whether the object image distance R _X corresponding to an object image _X and the object image angle θ _X satisfy a predetermined relationship. For example, when the relationship between the object image distance R _X and the object image angle θ _X is such that the coordinates of the object image X fall within the range of the touch region 103 , the object image X is judged as a real image, and vice versa.

Please refer to Figure 13. Figure 13 is a schematic diagram of an optical touch screen system 1300 according to a third embodiment of the present invention. Compared with the optical touch screen system 100, the optical touch screen system 1300 adds an image sensor 109, which functions similarly to the mirror 108, and is mainly used to improve the accuracy of determining the position of the contact point. Preferably, the image sensor 109 can be disposed in the upper right corner of the touch area 103. The optical touch screen system 1300 operates similarly to the optical touch screen system 600, as described in detail below.

Please refer to Figure 14 and refer to Figure 15 at the same time. Figure 14 is a flow chart illustrating the position of the optical touch screen system 1300 to detect contact points. Figure 15 is a schematic diagram showing the flow of Figure 14. In addition, the steps disclosed in FIG. 14 can be clearly explained for convenience of the related drawings, and may not actually be performed according to the flow disclosed in FIG. The steps are as follows:

Step 1401: The light-emitting element 102 emits light, is reflected by the contact points O ₁ and O ₂ , and generates object images I _O11 and I _O21 on the two-dimensional image F ₁ sensed by the image sensor 101, and is also applied to the image sensor 109. The sensed two-dimensional image F ₂ produces objects like I _O19 and I _O29 .

Step 1402: The angle measuring device 106 is located in the X-axis direction according to the object images I _O11 and I _O21 in the two-dimensional image F _{1 and} in the X-axis direction according to the object images I _O19 and I _O29 in the two-dimensional image F ₂ . The position image angles θ _O11 , θ _{O21 ,} and θ _O19 , θ _O29 are respectively generated. Note that the angle reference of θ _O19 and θ _O29 is mainly the image sensor 109.

Step 1403: The processing device 107 uses the light-emitting elements 102 as a starting point to generate real-image lines SL _O11 and SL _O21 according to the object image angles θ _O11 and θ _O21 , and then uses the position of the image sensor 109 as an origin, respectively, according to the object image. The angles θ _O19 and θ _O29 generate real image lines SL _O19 and SL _O29 .

Step 1404: Next, the processor 107 calculates the real image lines SL _O11 , SL _O21 , SL _O19 , SL _O29 and the virtual image lines SL _G1 , SL _G2 , and calculates and generates four candidate coordinates O _C1 , O _C2 , O _C3 and O _C4 .

Step 1405: The distance measuring device 105 generates the object image distances R _O11 and R _O21 according to the positions of the object images I _O11 and I _O21 in the Y-axis direction of the two-dimensional image F ₁ .

Step 1406: The processor 107 selects the candidate coordinates that have the smallest error from the object image distance R _O11 on the real image line SL _O11 as the coordinates of the last output contact point O ₁ ; the processor 107 selects the object image distance on the real image line SL _O21 . The candidate coordinates with the smallest error of R _O21 are used as the coordinates of the last output contact point O ₂ .

As can be seen from the above, the optical touch screen system 1300 can first measure the object image angle through the image sensors 101 and 109, and then determine the coordinate with the smallest error among the candidate coordinates according to the distance measured by the distance measuring device 105. The output coordinate of the last contact point.

In addition, the object image distance measured by the distance measuring device 105 is only used in steps 1407 and 1408 to determine which of the candidate coordinates is the output coordinate, so the accuracy of the measured object image distance need not be too high. In fact, the output coordinates of the contact point are still determined by the calculation of the processor 107 from the measured angle.

Please refer to Figure 16 and Figure 17. 16 and 17 are schematic views for explaining the structure and operation principle of the distance measuring device 105 of the present invention. In the manner of the arrangement of Fig. 1, the distance measuring device 105 is used to measure the object image distance R _O1 between the contact point O ₁ and the light-emitting element 102. The distance measuring device 105 includes a lighting/sensing control circuit 110 and a distance calculating circuit 140. The illumination/sensing control circuit 110 is configured to generate a control signal S _C to control the light emitting element 102 and the image sensor 101. The coupling relationship between the internal components of the distance measuring device 105 is as shown in Fig. 1, and therefore will not be described again. In addition, in order to improve the accuracy, the lenses LEN ₁ and LEN _{2 may be} separately disposed in front of the image sensor 101 and the front side of the light-emitting element 102, respectively.

The control signal S _C generated by the illumination/sensing control circuit 110 includes an illumination pulse signal S _LD , a shutter pulse signal S _ST , a phase signal S _P , a read signal S _RE , and a known distance signal S _D . The distance measuring device 105 can be divided into two phases during ranging: 1. distance sensing phase; 2. noise sensing phase. When the distance measuring device 105 is in the distance sensing phase, the illuminating/sensing control circuit 110 simultaneously generates the illuminating pulse signal S _LD indicating "lighting" and the shutter pulse signal S _ST indicating "on", and the pulse widths of both are It is T _C ; then the illumination/sensing control circuit 110 simultaneously generates the read signal S _RE indicating "read" and the phase signal S _P indicating "sum", and the pulse widths of both are T _R . When the distance measuring device 105 is in the noise sensing phase, the illumination/sensing control circuit 110 generates a shutter pulse signal S _ST indicating "on" and the illumination pulse signal S _LD indicates "no illumination", and the pulse of the shutter pulse signal The width is T _C ; then the illumination/sensing control circuit 110 simultaneously generates the read signal S _RE indicating "read" and the phase signal S _P indicating "noise", and the pulse widths of both are T _R .

The illuminating element 102 is controlled by the illuminating/sensing control circuit 110 for emitting the detecting light L _ID to the contact point O ₁ according to the illuminating pulse signal S _LD such that the contact point O ₁ generates the reflected light L _RD . More specifically, when the illuminating pulse signal S _LD indicates "lighting", the illuminating element 102 emits the detecting light L _ID to the contact point O ₁ ; when the illuminating pulse signal S _LD indicates "no illuminating", the illuminating element 102 does not The detection light L _{ID is} emitted.

One of the behaviors of the image sensor 101, such as the Qth row sensing unit row CS _Q , includes N side-by-side sensing units CS _{(Q, 1)} ~ CS _{(Q, N)} , and each sense The height of the measuring unit is equal to the pixel height H _PIX , which means that the total width of the N side-by-side sensing units CS _{(Q, 1)} ~ CS _{(Q, N)} is N × H _PIX . The sensing units CS _{(Q, 1)} ~ CS _{(Q, N) are} used to sense the energy of the light condensed by the lens LEN ₁ according to the shutter pulse signal S _ST . More specifically, when the shutter pulse signal S _ST indicates "on", the sensing unit CS _{(Q, 1)} ~ CS _{(Q, N)} senses the light condensed by the lens LEN ₁ (such as background light L _B or reflection) The energy of the light L _RD ) is used to generate the light sensing signal; when the shutter pulse signal S _ST indicates “off”, the sensing unit CS _{(Q, 1)} ~ CS _{(Q, N)} does not converge the lens LEN ₁ The energy of light. For example, when the shutter pulse signal S _ST indicates "on", the sensing unit CS _{(Q, 1)} senses the energy of the light condensed by the lens LEN ₁ and generates the light sensing signal S _{LS1 accordingly} ; the sensing unit CS _{(Q, 2)} senses the energy of the light condensed by the lens LEN ₁ and generates the light sensing signal S _LS2 ; and so on, the sensing unit CS _{(Q, N)} senses the light condensed by the lens LEN ₁ The energy is generated accordingly to generate a light sensing signal S _LSN . In addition, when the read signal S _RE indicates "read", the sensing units CS _{(Q, 1)} ~ CS _{(Q, N)} respectively output the light sensing signals S _LS1 ~ S _LSN , which is the two-dimensional image F The video signal of the Qth line.

The distance calculation circuit 140 includes a plurality of storage units for storing the light sensing signals S _LS1 ~S _LSN output by the sensing units CS _{(Q, 1)} ~ CS _{(Q, N)} , and according to the phase signal S _P , Set the properties of the received light sensing signal. In the present embodiment, the distance calculation circuit 140 includes N storage units M ₁ to M _N as an example. When the phase signal S _P indicates "sum", the storage units M ₁ -M _N set the received light sensing signals S _LS1 ~S _{LSN to} be positive, that is, the received light sensing signals S _LS1 ~S _{LSN are} based on The phase signal S _P indicates "sum" and is marked as positive light sensing signal S _LS1+ ~S _LSN+ ; when the phase signal S _P indicates "noise", the storage unit M ₁ ~M _N will receive the received light sensing signal S _LS1 ~ S _{LSN is} set to be negative, that is, the received optical sensing signals S _LS1 ~ S _LSN are marked as negative light sensing signals S _LS1 ~ ~S _LSN- according to the phase signal S _P indicating "noise". The distance calculation circuit 140 can calculate the object image distance R _O1 according to the positive light sensing signal S _LS1+ ~S _LSN+ and the negative light sensing signal S _LS1 - ~S _LSN- . The operation principle of the distance calculation circuit 140 for calculating the object image distance R _O1 will be described below.

As shown in the left half of Fig. 17, during the distance sensing phase, the illumination/sensing control circuit 110 generates an illumination pulse signal S _LD representing "lighting", so that the illumination element 102 emits the detection light L _ID. The point O _{1 is} contacted so that the contact point O ₁ produces reflected light L _RD . At this time, the illumination/sensing control circuit 110 generates a shutter pulse signal S _ST representing "on", so that the sensing unit CS _{(Q, 1)} ~ CS _{(Q, N)} senses the reflected light L _RD and the background light L The energy of _B to generate the light sensing signals S _LS1 ~S _{LSN , respectively} . Then, the illumination/sensing control circuit 110 outputs a read signal S _RE representing "read", so that the image sensor 101 outputs the light sensing signals S _LS1 ~S _LSN to the distance calculation circuit 140, and emits/senses The control circuit 110 generates a phase signal S _P representing the "sum" to indicate that the light sensing signal received by the distance calculating circuit 140 is a light sensing signal in the distance sensing phase, that is, a positive light sensing signal S. _LS1+ ~S _LSN+ . In the distance sensing phase, the reflected light L _{RD is} mainly concentrated and imaged on the sensing unit CS _{(Q, K)} , and the value of the positive light sensing signal S _LS1+ ~S _LSN+ received by the distance calculating circuit 140 is 17th. As shown in the upper right half of the figure, the sensing unit CS _{(Q, K)} simultaneously senses the background light L _B and the reflected light L _RD (that is, the contact point O _{1 is} imaged on the sensing unit CS _{(Q, K)} ). Therefore, the sensing signal S _LSK+ is equal to the energy B _K accumulated by the sensing unit CS _{(Q, K)} sensing the background light L _B plus the sensing unit CS _{(Q, K)} sensing the reflected light L _RD accumulated The energy R _K , while the other sensing units only receive the background light L _B . Therefore, the sensing signal S _LS1+ is equal to the sensing unit CS _{(Q, 1)} sensing the energy B ₁ accumulated by the background light L _B ; the sensing signal S _LS2+ is equal to the sensing unit CS _{(Q, 2)} sensing the background The energy B ₂ accumulated by the light L _B ; and so on, the sensing signal S _{LSN +} is equal to the energy B _N accumulated by the sensing unit CS _{(Q, N)} sensing the background light L _B .

As shown in the left half of Fig. 17, during the noise sensing phase, the illumination/sensing control circuit 110 generates a shutter pulse signal S _ST representative of "on", so that the sensing unit CS _{(Q, 1)} ~ The CS _{(Q, N)} senses the light condensed by the lens LEN ₁ to generate the light sensing signals S _LS1 ~S _LSN . However, at this time, the illumination/sensing control circuit 110 generates the illumination pulse signal S _LD representing "no illumination", so that the illumination element 102 does not emit the detection light L _ID to the contact point O ₁ , and the contact point O ₁ also No reflected light L _{RD is} produced. Then, the illumination/sensing control circuit 110 outputs a read signal S _RE representing "read", so that the image sensor 101 outputs the light sensing signals S _LS1 ~S _LSN to the distance calculation circuit 140, and emits/senses The control circuit 110 generates a phase signal S _P representing "noise" to indicate that the light sensing signal received by the distance calculating circuit 140 is a light sensing signal in the noise sensing phase, that is, a negative light perception. Test signal S _LS1- ~S _LSN- . At this time, the distance calculation circuit 140 receives the light sensing signal value S of _LS1- ~ S _LSN- As shown in the lower half of the right in FIG. 17. Since the shutter pulse signal S _ST is the same as the pulse width of the noise sensing phase and the noise sensing phase (all are the time length T _C ). Therefore _, the light sensing signals S _LS1 ~S _LSN generated by the sensing unit CS _(Q,1) ~CS _(Q,N) in the distance sensing phase and the noise sensing phase correspond to the accumulation of the background light L _B . equal. In other words, the accumulated energy of the background light in the positive light sensing signal S _LS1+ ~S _LSN+ is equal to the energy (B ₁ ~B _N ) accumulated by the background light in the negative light sensing signal S _LS1- ~S _LSN- .

After passing the distance sensing phase and the noise sensing phase, the illumination/sensing control circuit 110 generates a phase signal S _P representative of the "calculated distance". At this time, the distance calculation circuit 140 subtracts the positive light sensing signal and the negative light sensing signal in the storage unit, and selects the storage unit with the largest value stored after subtraction and determines the reflected light L _RD for image sensing. The imaging position on the device 101. That is, the values stored by the storage units M ₁ -M _{N of} the distance calculation circuit 140 are equal to the values of the positive light sensing signals S _LS1+ ~S _LSN+ minus the values of the negative light sensing signals S _LS1 - ~S _LSN- , respectively. . More specifically, the storage unit M ₁ stores the positive light sensing signal S _LS1+ and the negative light sensing signal S _LS1- , since the positive light sensing signal S _LS1+ is equal to B ₁ and the negative light sensing signal S _LS1 is equal to B ₁ , The stored value of the storage unit M ₁ is zero after the subtraction; the storage unit M ₂ stores the positive light sensing signal S _LS2+ and the negative light sensing signal S _LS2- , because the positive light sensing signal S _LS2+ is equal to B ₂ and the negative light perception The test signal S _LS2- is equal to B ₂ , so the value stored by the storage unit M ₂ after subtraction is zero; and so on, the storage unit M _K stores the positive light sensing signal S _LSK+ and the negative light sensing signal S _LSK- , Since the positive light sensing signal S _LS2+ is equal to (B _K +R _K ) and the negative light sensing signal S _LS2- is equal to B _K , the storage unit M _K stores the value R _K after the subtraction; the storage unit M _N stores The positive light sensing signal S _LSN+ and the negative light sensing signal S _LSN- , since the positive light sensing signal S _LSN+ is equal to B _N and the negative light sensing signal S _LSN− is equal to B _N , the storage unit M _N is subtracted and stored The value is zero. In other words, among the storage units M ₁ to M _N , the value of the storage unit M _K is equal to R _K , and the values of the other storage units are all equal to zero, so the distance calculation circuit 140 can select the storage unit M _K , that is, The light sensing signal stored by the storage unit M _K has an energy corresponding to the reflected light L _RD . Since the storage unit M _K is a light sensing signal generated by the storage sensing unit CS _{(Q, K)} , the distance calculation circuit 140 can determine that the reflected light L _RD generated by the contact point O ₁ is mainly concentrated and imaged in the sensing. Unit CS _{(Q, K)} . In this way, the distance calculation circuit 140 can further concentrate the image based on the reflected light L _RD generated by the contact point O ₁ on the sensing unit CS _{(Q, K)} , and derive the reflected light L _{RD in} FIG. 16 from the following equation. Imaging position D _CS : D _CS = K × H _PIX ... (1);

In addition, since the straight line L _F formed between the focus O _F of the lens LEN ₁ and the sensing unit CS _{(Q, 1)} in FIG. 16 is parallel to the detection light L _ID , the detection light L _ID and reflection are light L _RD angle θ ₁ of the straight line and the reflected light L _F L _RD is equal to the angle θ _2. In other words, the relationship between tan θ ₁ and tan θ ₂ can be expressed by the following formula:

Tan θ ₁ = L / D _M = tan θ ₂ = D _CS / D _F (2);

Wherein L represents a predetermined distance between the light-emitting element 102 and the image sensor 101 (detecting light L _ID and line L _F ), D _CS represents an imaging position of the reflected light L _RD , and D _F represents a focal length of the lens LEN ₁ . According to the formula (2), the object image distance R _O1 can be expressed by the following formula:

R _O1 = (D _F × L) / D _CS ... (3);

Therefore, the distance calculation circuit 140 can first calculate the imaging position D _CS by the equation (1), and then calculate the object image distance R _O1 according to the predetermined distance L and the focal length D _F by the equation (3).

Briefly, in the distance measuring device 105, within a distance sensing stage, the light emitting / sensing control circuit 110 controls the light emitting element 102 emits light L _ID detecting emitted to the contact point O _1, and the sensing unit CS _{( Q,1)} ~CS _(Q,N) senses the light condensed by the lens LEN ₁ (such as the reflected light L _RD and the background light L _B ) and the positive light sensing signal S _LS1+ ~S _LSN+ generated therefrom is stored in the storage unit M ₁ ~M _N . During the noise sensing phase, the illumination/sensing control circuit 110 controls the light-emitting element 102 not to emit the detection light L _ID , and the sensing unit CS ₁ ~CS _N senses the light condensed by the lens LEN ₁ (such as the background light). The negative light sensing signals S _LS1+ ~S _LSN+ generated according to L _B ) are stored in the storage units M ₁ -M _N . In this case, the storage unit M ₁ ~ M _N value will equal the positive optical sensing signal S _{LS1 +} ~ S _{LSN +} subtracting the negative-sense signal _S LS1- ~ S _LSN-. Therefore, the value of the memory cell M _K corresponding to the sensing unit CS _{(Q, K)} condensed by the reflected light L _RD may be greater than the value of the other memory cells. Thus, the distance calculation circuit 140 can determine the sensing unit CS _{(Q, K)} where the reflected light L _RD converges, and calculate the imaging position D _CS of the back-measuring light L _RD accordingly. Therefore, the distance calculation circuit 140 can calculate the object image distance R _O1 according to the imaging position D _CS , the focal length D _{F of the} lens LEN ₁ , and the predetermined distance L.

In summary, the optical touch screen system of the present invention can determine the true coordinates of each contact point by the verification of the distance measuring device in the case of a plurality of contact points. Therefore, the optical touch screen system of the present invention can be applied to multiple contact points and accurately determine the position of each contact point, thereby providing greater convenience to the user.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

100, 600, 1300. . . Optical touch screen system

101, 109. . . Image sensor

102. . . Light-emitting element

103. . . Touch area

104. . . Absorbing element

105. . . Distance measuring device

106. . . Angle measuring device

107. . . processor

120. . . Processing device

108. . . Reflective element

S _C , S _LD , S _ST , S _RE , S _P , S _LS . . . Signal

SL. . . straight line

R. . . distance

O. . . Contact point

P. . . Calibrator

I. . . image

θ. . . angle

CS. . . Sensing unit

LEN ₁ , LEN ₂ . . . Lens

D _CS . . . Imaging position

D _F . . . focal length

L _ID , L _RD . . . Light

1 is a schematic view of an optical touch screen system according to a first embodiment of the present invention.

2 is a schematic view showing the optical touch screen system of the first embodiment of the present invention in a correction stage.

Figure 3 is a schematic view showing the optical touch screen system of the first embodiment of the present invention in normal operation.

Figure 4 is a side view of the optical touch screen system of the first embodiment of the present invention.

Figure 5 is a top plan view of the optical touch screen system of the first embodiment of the present invention.

Figure 6 is a schematic view of an optical touch screen system of a second embodiment of the present invention.

Figure 7 is a flow chart for explaining the position of the touch point of the optical touch screen system of the second embodiment of the present invention.

Figures 8-12 are schematic diagrams illustrating the flow of Figure 7.

Figure 13 is a schematic view of an optical touch screen system according to a third embodiment of the present invention.

Figure 14 is a flow chart for explaining the position of the touch point of the optical touch screen system of the third embodiment of the present invention.

Figure 15 is a schematic diagram showing the flow of Figure 14.

Fig. 16 and Fig. 17 are schematic views for explaining the structure and working principle of the distance measuring device of the present invention.

600. . . Optical touch screen system

101. . . Image sensor

102. . . Light-emitting element

103. . . Touch area

104. . . Absorbing element

105. . . Distance measuring device

106. . . Angle measuring device

107. . . processor

120. . . Processing device

108. . . Reflective element

S _C . . . Signal

R. . . distance

O. . . Contact point

θ. . . angle

Claims (27)

An optical touch screen system includes: a touch area; a light emitting element disposed around the touch area, and the light emitting element is at least partially located above the touch area, so that the light emitted by the light emitting element can span The touch area is disposed on at least a portion of the touch area to reflect light emitted by the light emitting element and to generate a mirror image of the touch area; an image sensor disposed above the light emitting element Receiving a set of contact points located in the touch area and the mirror, reflecting the light of the light emitting element, and generating a two-dimensional image; wherein the two-dimensional image comprises a set of object images, the group image includes a corresponding image Forming a real image of the set of contact points and the light reflected by the mirror to the light emitting element to generate a virtual image corresponding to the set of contact points; and processing means for using the set of real images and the set of virtual images in the second a position in the dimensional image, generating a set of output coordinates corresponding to the set of contact points, the processing device comprising: a distance measuring device connecting the image sensor and the hair And an element for controlling the light-emitting element and the image sensor, and generating a group object image distance corresponding to the group image according to the coordinates of the group image in the first direction in the two-dimensional image image An angle measuring device connected to the image sensor for displaying the image according to the group a coordinate in a second direction in the two-dimensional image, generating a group image angle corresponding to the group image; and a processor connecting the distance measuring device and the angle measuring device for using the group The object image distance and the group image angle produce the set of output coordinates. The optical touch screen system of claim 1, wherein the processing device generates a set of real image lines according to the set of real images and the position of the image sensor in the two-dimensional image, and according to the set of virtual images and the image sense The image of the detector is imaged in the two-dimensional image to generate a first set of virtual image lines, and the processing device generates the set of output coordinates according to the set of real image lines and the first set of virtual image lines. The optical touch screen system of claim 2, wherein the plurality of intersections of the set of real image lines and the set of virtual image lines are a set of candidate coordinates, and the candidate coordinates are selected according to a distance from the image sensor. At least one of the group of candidate coordinates is labeled as the output coordinate of the group. The optical touch screen system of claim 1, wherein the first real image line of the set of real image lines corresponds to one of the first real images of the set of real images, and the first real image system corresponds to one of the set of contact points. a contact point; the first object image distance of the group image corresponds to the first object image of the group object image, and the first object image angle of the group image angle corresponds to the first object image . The optical touch screen system of claim 4, wherein the first object image distance represents a distance between the first object image and the distance measuring device; wherein the distance measuring device is adjacent to the image sensor. The optical touch screen system of claim 5, further comprising a real image determining device electrically connected to the distance measuring device and the angle measuring device, according to whether the first object image distance and the first object image angle are consistent with one The predetermined relationship determines whether the first object image is the first real image. The optical touch screen system of claim 6, wherein the set of candidate coordinates is located in the first real image line as a first set of candidate coordinates, and the processing device selects the first of the first set of candidate coordinates to be closest to the first object. The first candidate coordinate of the image distance is used as the output coordinate of the first contact point. The optical touch screen system of claim 1, further comprising a light absorbing element disposed around the touch area to prevent light of the light emitting element from being reflected to the image sensor. The optical touch screen system of claim 1, wherein the image sensor is located adjacent to the light emitting element. The optical touch screen system of claim 1, wherein the light emitting element is a two-dimensional light source. The optical touch screen system of claim 10, wherein the two-dimensional light source comprises: a line source; and a light source element conversion device; wherein the light element conversion device converts the line source into the two-dimensional source to generate Illuminating the light in the touch area. The optical touch screen system of claim 11, wherein the line source generates light through a laser diode or a light emitting diode. The optical touch screen system of claim 10, wherein the light source conversion device is a cylindrical mirror or a microelectromechanical mirror module. An optical touch screen system includes: a touch area; a light emitting element disposed around a touch area, and the light emitting element is at least partially located above the touch area, so that the light emitted by the light emitting element can span The touch area is disposed above the light emitting element, and receives light reflected by the contact point of the group of the touch area to generate a two-dimensional image; wherein the two-dimensional image is generated; The image includes a group image corresponding to the group of contact points; a distance measuring device connecting the light emitting component and the image sensor for controlling The light-emitting element and the image sensor generate a group image object distance corresponding to the group image according to the coordinates of the group image in the first direction in the two-dimensional image; an angle measuring device, Connecting the image sensor to generate a group image angle corresponding to the group image according to coordinates of the group image in a second direction in the two-dimensional image; and a processor according to the The group image distance and the group image angle produce a set of output coordinates corresponding to the group of contact points. The optical touch screen system of claim 14, wherein the first object image of the group image corresponds to a first contact point of the set of contact points; the first object image distance of the group image distance The angle of the object image corresponds to the first object image. The optical touch screen system of claim 15 further comprising a first lens for concentrating a background light or light reflected by the first contact point, wherein the image sensor is configured to sense the first The energy of the light concentrated by a lens to generate M light sensing signals, the distance measuring device comprising: a light emitting/sensing control circuit connected to the light emitting element for controlling the light emitting element during a distance sensing phase Illuminating, and simultaneously controlling the image sensor to sense the energy of the light concentrated by the first lens to generate M first light sensing signals, controlling the light emitting element to emit light during a noise sensing phase, and Simultaneously controlling the image sensor to sense the energy of the light concentrated by the first lens to generate M second light sensing signals; Wherein M represents a positive integer; and a distance calculation circuit is coupled to the image sensor for determining the first contact point reflection according to the M first light sensing signals and the M second light sensing signals Light on the image sensor in an image forming position in the first direction, and according to the imaging position, a focal length of the first lens, a predetermined distance between the light emitting element and the image sensor, To calculate the first object image distance. The optical touch screen system of claim 16, wherein the distance calculation circuit calculates the first object image distance according to the following formula: R _O1 = (D _F × L) / D _CS ; wherein R _O1 represents the first An object image distance, D _F represents the focal length of the first lens, L represents the predetermined distance between the light emitting element and the image sensor, and D _CS represents the image forming position. An optical touch screen system includes: a touch area; a light emitting element disposed around the touch area, and the light emitting element is at least partially located above the touch area, so that the light emitted by the light emitting element can span The first image sensor is disposed above the light-emitting element, and receives light reflected by the group of contact points of the touch area to reflect the light-emitting component, and accordingly generates a first two-dimensional image; The first two-dimensional image includes a first group of real images corresponding to the set of contact points; a second image sensor is disposed around the touch area to receive the set of contact points located in the touch area. Reflecting light of the illuminating element and generating a second two-dimensional image; wherein the second two-dimensional image comprises a second set of real images corresponding to one of the set of contact points; and a distance measuring device connecting the illuminating element with The first image sensor is configured to control the first image sensor and the light emitting element, and generate a coordinate corresponding to the first image according to a coordinate of the first set of real images in a first direction in the two-dimensional image. a first set of object image distances of a set of real images; a processor configured to generate a first set of real image lines according to the positions of the first set of real images and the first image sensor in the first two-dimensional image And generating a second set of real image lines according to the positions of the second group of real images and the second image sensor in the second two-dimensional image, the processing device according to the first group of real image lines and the first The group is a solid line and is generated corresponding to the group a set of candidate coordinates, and according to the set of candidate coordinates and the first set of object distances, generating a set of output coordinates corresponding to the set of contact points; a first angle measuring device connecting the first image sensor And generating a first group image angle corresponding to one of the set of contact points according to the coordinates of the first group of real images in a second direction in the first two-dimensional image; and a second angle measuring device connecting the The second image sensor generates a first group image angle corresponding to one of the set of contact points according to the coordinates of the second group of real images in the second direction in the second two-dimensional image. The optical touch screen system of claim 18, wherein the first group image distance represents a distance between the set of contact points and the distance measuring device; wherein the distance measuring device is adjacent to the image sensor. The optical touch screen system of claim 18, wherein one of the first set of real image straight lines corresponds to a third contact point of the set of contact points, and the first set of image distances is one of The three object image distance corresponds to the third contact point. The optical touch screen system of claim 20, wherein the set of candidate coordinates is located in the third real image line as a third set of candidate coordinates, and the processing device selects the third of the third set of candidate coordinates closest to the third object. The third candidate coordinate of the image distance is used as the output coordinate of the third contact point. The optical touch screen system of claim 18, further comprising a light absorbing element disposed around the touch area to prevent light of the light emitting element from being reflected to the image sensor. The optical touch screen system of claim 18, wherein the image sensor is located adjacent to the light emitting element. The optical touch screen system of claim 18, wherein the light emitting element is a two-dimensional light source. The optical touch screen system of claim 24, wherein the two-dimensional light emitting element comprises: a line source; and a light element switching device; wherein the light source converting device converts the line source into the two-dimensional source and generates Illuminating the light in the touch area. The optical touch screen system of claim 25, wherein the line source generates light through a laser diode or a light emitting diode. The optical touch screen system of claim 25, wherein the light source conversion device is a cylindrical mirror or a microelectromechanical mirror module.