A photoelectric detector and a photoelectric touch positioning method thereof

Abstract

The present invention provides a photodetector, comprising: a light scanning mechanism for emitting a light beam to scan the touch area of ​​a display screen; an information processing circuit, which is electrically connected to the light scanning mechanism; a detection unit, which is arranged on one side of the display screen and is electrically connected to the information processing circuit, and is used to detect the light spot of the light beam trajectory of the light scanning mechanism; wherein the information processing circuit includes a timing unit, and the timing unit is used to obtain the time equivalent corresponding to the light spot, and then determine the angular arc of the constant speed rotation of the light beam, and then determine the coordinate position corresponding to the light spot detected by the touch member on the display screen. The photodetector of the present invention emits a light beam through a light source, a motor, and an optical element fixed at one end of the motor, which can avoid the occurrence of a scanning blind area in the touch area of ​​the display screen, and has low electromagnetic noise and weak electromagnetic interference during use, and can achieve touch positioning with high precision.

Description

Technical Field

[0001] The present invention relates to the field of touch positioning technology, and in particular to a photoelectric detector and a photoelectric touch positioning method thereof. Background Art

[0002] At present, touch screens have been promoted to many fields as the easiest human-computer interaction technology. Among the touch screen implementation schemes based on photoelectric technology, the most mature one is to arrange infrared emitting tubes and infrared receiving tubes on the four sides of the screen, forming a horizontal and vertical cross infrared matrix in one-to-one correspondence. The specific position of the touched object can be detected according to the different shielding light, and the application range is very wide. However, in order to form an effective judgment of the touch point, infrared emitting tubes and infrared receiving tubes must be arranged around the touch frame, which has a relatively complex structure and high implementation cost;

[0003] In addition, the prior art also uses light scanning to achieve touch positioning. For example, the invention patent laser scanning touch screen with publication number CN109992164A discloses the following content, including at least two laser scanning heads, the laser scanning head includes a base, and a reflective sensing group and a rotating mechanism are arranged on the base; a rotation angle detection device is also provided, and the rotating component is linked to the rotation angle detection device; the base is also provided with a photosensitive receiving head; the rotating component on the base drives the laser transmitting head to rotate, and then drives the laser beam emitted by the laser transmitting head to rotate; during the rotation of the laser transmitting head, when the laser beam irradiates the touch element, reflection will be generated to determine the parameters of one-dimensional coordinates of the touch element; through at least two laser scanning heads, the one-dimensional coordinates of the touch element are determined respectively, and then at least two-dimensional coordinates are determined, and then the coordinate position of the touch element on the touch screen is determined.

[0004] However, this technology has at least the following defects: (1) Since the receiving sensitivity of the photodiode is directional, the deviation of the incident light from the central axis of the photodiode will cause the receiving sensitivity to decrease. At the same time, the reflected light intensity will be weaker as the distance between the touch element coordinates and the receiving photosensitive device increases. At the same time, the indicator on the touch screen is not always on the optical axis of the laser scanning beam. Since the direction of the reflected light is determined by the normal of the indicator, the reflected light does not always return to the emission point. Therefore, there will be a receiving blind spot for the reception of the reflected light; (2) When measuring the angle through the code disk, the resolution of the scale is limited by the area of ​​the disk due to the calibration of the scale on the physical disk, resulting in low resolution of the code disk measuring angle, which in turn affects the touch positioning accuracy of the display screen; (3) The high-speed mechanical drive of the code disk will affect the high-speed rotation performance. Since the code disk is a physical disk, it needs to be larger in size due to the code disk scale accuracy requirements. However, the larger the diameter, the greater the electromagnetic noise generated by high-speed rotation, causing electromagnetic interference and affecting the user experience. Summary of the invention

[0005] Based on this, in order to solve the above problems, it is necessary to propose a photoelectric detector with strong versatility and applicable to display screens of various sizes, as well as a method for realizing touch positioning of the display screen with no blind area, low electromagnetic noise and high precision through the photoelectric detector.

[0006] The embodiment of the present invention is implemented by the following technical solution: a photoelectric detector, comprising:

[0007] A light scanning mechanism for emitting a light beam to scan a touch area of ​​the display screen;

[0008] An information processing circuit electrically connected to the optical scanning mechanism;

[0009] At least two detection units, disposed on one side of the display screen, both electrically connected to the information processing circuit, for detecting light spots of the light beam trajectory of the light scanning mechanism;

[0010] The information processing circuit includes a timing unit, which is used to obtain the time equivalent corresponding to the light spot, thereby determining the angular radian of the constant speed rotation of the light beam, and further determining the coordinate position corresponding to the light spot detected by the touch element on the display screen.

[0011] Furthermore, the optical scanning mechanism includes:

[0012] A light source for generating an incident light beam;

[0013] an optical element for reflecting the incident light beam; and

[0014] A motor is used to drive the optical element to rotate.

[0015] According to a preferred embodiment, the at least two detection units include a zero-crossing detection unit and a range positioning unit, wherein:

[0016] The zero-crossing detection unit is arranged on the same horizontal line as the incident point of the light beam on the optical element, and is used to detect the light spot of the light beam trajectory and determine the starting and ending points of one cycle of light scanning.

[0017] Furthermore, the information processing circuit further includes: a first preamplifier unit, a second preamplifier unit, a clock unit, a logic control / calculation unit, a RAM unit, a radio frequency signal transceiver unit, an interface unit and a drive unit, wherein:

[0018] The input end of the first preamplifier unit is connected to the zero-crossing detection unit, and the output end is connected to the timing unit, so as to obtain the start time of the light scanning through the timing unit;

[0019] The input end of the second preamplifier unit is connected to the range positioning unit, and the output end is connected to the timing unit, so as to obtain the first time equivalent of the light scanning through the timing unit;

[0020] The first output end of the clock unit is connected to the timing unit to provide a timing pulse; the second output end is connected to the logic control / calculation unit to provide a timing clock;

[0021] One end of the driving unit is connected to the motor and the light source, and the other end is connected to the logic control / computing unit;

[0022] The RAM unit, the radio frequency signal transceiver unit and the interface unit are all connected to the logic control / calculation unit, wherein:

[0023] The RAM unit is used to cache the control process data of the logic control / computation unit, the radio frequency signal transceiver unit communicates with the touch element through radio frequency, and the interface unit is connected to the main computer of the display screen.

[0024] According to a preferred embodiment, the timing unit includes a first timer, a second timer, a third timer and a fourth timer, wherein:

[0025] The first timer is connected to the first preamplifier unit to obtain the time equivalent of one rotation of the light beam;

[0026] The second timer is connected to the second preamplifier unit to obtain the first time equivalent of the light beam from the zero-crossing detection unit to the range positioning unit;

[0027] The third timer is connected to the logic control / calculation unit to obtain a second time equivalent of the light beam from the zero-crossing detection unit to the range positioning unit corresponding to another photoelectric detector;

[0028] The fourth timer is connected to the logic control / calculation unit to obtain a third time equivalent of the light beam from the zero-crossing detection unit to the touch member.

[0029] The present invention also provides a method for photoelectric touch positioning, which is applied to the photoelectric detector as described above, and comprises the following steps:

[0030] For the image pixel area of ​​the display, the first photodetector and the second photodetector are used alternately to perform light beam scanning of two coordinate systems.

[0031] The two coordinate systems include a first coordinate system generated by a light beam trajectory emitted by the light scanning mechanism of the first photodetector passing through the zero detection unit, the range positioning unit, the touch member, and each light spot of the range positioning unit of the second photodetector, and a second coordinate system generated by a light beam trajectory emitted by the light scanning mechanism of the second photodetector passing through the zero detection unit, the range positioning unit, the touch member, and each light spot of the range positioning unit of the first photodetector;

[0032] The time taken for the light beam trajectory to pass through the zero detection unit to each of the above light spots is accumulated by the timing unit to obtain the time equivalent corresponding to each light spot, and then the angular radian of the constant speed rotation of the light beam is determined;

[0033] The first coordinate and the second coordinate are integrated, and the coordinate value of the light point corresponding to the touch element on the display screen is calculated according to the trigonometric function.

[0034] Furthermore, the timing unit accumulates the time from when the light beam trajectory passes through the zero detection unit to each of the light spots, obtains the time equivalent corresponding to each of the light spots, and then determines the angular radian of the constant speed rotation of the light beam, specifically including:

[0035] When the light beam emitted by the first photodetector reaches the zero-crossing detection unit, the zero-crossing detection unit generates a photoelectric pulse and sends it to the timing unit, starting each timer to start timing;

[0036] When the light beam reaches the range positioning unit, the range positioning unit generates a photoelectric pulse and sends it to the timing unit, controls the second timer to stop timing, obtains the first time equivalent t1, and then determines the angular radian between the zero-crossing detection unit and the range positioning unit;

[0037] When the light beam reaches the touch member, the touch member generates a photoelectric pulse and sends it to the timing unit, controls the fourth timer to stop timing, obtains a third time equivalent t3, and then determines the angular radian between the zero-crossing detection unit and the touch member;

[0038] When the light beam reaches the range positioning unit of the second photodetector, the range positioning unit generates a photoelectric pulse to the timing unit of the first photodetector, controls the third timer to stop timing, obtains the second time equivalent t2, and then determines the angular radian between the zero-crossing detection unit and the range positioning unit;

[0039] When the light beam rotates one circle and reaches the zero-crossing detection unit of the first photodetector, the zero-crossing detection unit generates a photoelectric pulse and sends it to the timing unit, controls the first timer to stop timing, and obtains the time equivalent t0 of one circle of light scanning;

[0040] The formula for calculating the angle in radians is as follows:

[0041]

[0042] In formula (1), t is the time equivalent, and t0 is the time equivalent of one light scan.

[0043] According to a preferred embodiment, after obtaining the time equivalent t0, the following steps are also included:

[0044] Read and cache the data of the first timer, the second timer, the third timer and the fourth timer, and reset the first timer, the second timer, the third timer and the fourth timer;

[0045] The photodetector in control stops beam emission and another photodetector is activated.

[0046] According to a preferred embodiment, before calculating the coordinate value of the light point corresponding to the touch element on the display screen, the method further includes:

[0047] The pixel resolution value of the image pixel area is obtained, and the length equivalent of the line between the two range positioning units is determined based on the pixel resolution value, and the angle between the line between the two range positioning units and a frame of the touch area is obtained.

[0048] The technical solution of the embodiment of the present invention has at least the following advantages and beneficial effects: the photoelectric detector of the present invention emits a light beam through a light source, a motor and an optical element fixed at one end of the motor, which can avoid a scanning blind area in the touch area of ​​the display screen, and has low electromagnetic noise and weak electromagnetic interference during use; the photoelectric detector emits a light beam to scan the touch area of ​​the display screen, and the light beam trajectories of the two photoelectric detectors pass through the zero-crossing detection unit, the range positioning unit and the touch member to obtain two coordinate systems through the logic control / calculation unit; based on the timing unit of the photoelectric detector, the time equivalent of each light spot is obtained, and then the angular radian of the constant speed rotation of the light beam is determined; the first coordinate and the second coordinate are integrated, and the coordinate value of the light spot corresponding to the touch member on the display screen is calculated according to the trigonometric function, that is, touch positioning can be achieved with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the structure of a photoelectric detector provided by an embodiment of the present invention;

[0050] Figure 2 A logic flow chart of a method for photoelectric touch positioning provided by an embodiment of the present invention;

[0051] Figure 3 A logic control / computing unit control timing flow chart provided for an embodiment of the present invention;

[0052] Figure 4 A schematic diagram of coordinate integration results provided by an embodiment of the present invention;

[0053] Icons: 10- optical scanning mechanism, 101- light source, 102- motor, 1021- hollow spindle, 1022- rotor, 1023- stator coil, 103- optical element, 11- zero-crossing detection unit, 12- range positioning unit, 13- information processing circuit, 131- first preamplifier unit, 132- timing unit, 1321- first timer, 1322- second timer, 1323- third timer, 1324- fourth timer, 133- driving unit, 134- second preamplifier unit, 135- clock unit, 136- logic control / calculation unit, 137- RAM unit, 138- RF signal transceiver unit, 139- interface unit. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0055] Example

[0056] See also Figure 1 As shown, this embodiment provides a photoelectric detector, including: an optical scanning mechanism 10, an information processing circuit 13, a zero-crossing detection unit 11 and a range positioning unit 12, wherein:

[0057] The zero-crossing detection unit 11 and the range positioning unit 12 are both arranged on the same side of the display screen, and in order to facilitate the calculation of the coordinate position of the touch element, the zero-crossing detection unit 11 is arranged on the same horizontal line of the light beam incident point on the optical element 103; it should be noted that in this embodiment, the zero-crossing detection unit 11, the range positioning unit 12 and the touch element all carry a photosensitive diode.

[0058] The optical scanning mechanism 10 is used to emit a light beam to scan the touch area image pixel area of ​​the display screen; specifically, the optical scanning mechanism 10 includes: a light source 101 for generating an incident light beam; an optical element 103 for reflecting the incident light beam; and a motor 102 for driving the optical element 103 to rotate.

[0059] In a preferred embodiment, the motor 102 has a hollow main shaft 1021, the optical element 103 is fixed at one end of the hollow main shaft 1021, the light source 101 is arranged at the other end of the hollow main shaft 1021, the incident light beam passes through the hollow main shaft 1021 and is incident on the optical element 103, wherein the optical element 103 is arranged such that when the hollow main shaft 1021 drives the rotation, the reflected light beam remains parallel to the touch area of ​​the display screen. The optical element 103 is a right-angle prism.

[0060] Furthermore, the motor 102 also includes a rotor 1022 and a stator coil 1023. Compared with the structure mentioned in the background technology, the rotating part of this embodiment adopts an outer rotor 1022 motor 102, and the excitation coil is installed on the stator without a mechanical commutation slip ring, which is more in line with the specifications of the electromagnetic compatibility standard.

[0061] Of course, in addition to the above-mentioned most preferred method, there are other implementation methods, such as setting the light source 101 on the rotating shaft of the motor 102 and setting the right-angle prism on the light source 101. Of course, since the light source 101 will also rotate during operation, and the light source 101 is a power device that requires a large current drive circuit to drive, it needs to adopt a mechanical contact method such as a brush slip ring to obtain power. It can be understood that this structure has at least the following disadvantages: (1) The mechanical contact has a large impedance relative to the large current, and the mechanical contact oxidizes after long-term operation, resulting in poor contact; (2) When the slip ring rotates at a high speed, the friction temperature of the contact point rises quickly, accelerating the aging of the electric contact; (3) When the slip ring rotates at a high speed, the high-speed wear of the contact will also cause poor contact; (4) The mechanical mechanism will also generate electromagnetic noise interference during the electrical operation process. Therefore, the laser scanning structure in the background technology is prone to circuit failure and mechanical failure, shortening the service life of the product.

[0062] Therefore, the most effective embodiment of this solution can solve the above technical problems. Laser scanning makes full use of optical principles, the laser transmitter head is fixedly installed, and the light beam is directly projected to the right-angle prism on the hollow main shaft 1021 of the motor 102 for reflection to achieve scanning, and there is no electrical connection with the rotating structure. Therefore, it is more in line with the specifications of the electromagnetic compatibility standard.

[0063] The information processing circuit 13 is electrically connected to the optical scanning mechanism 10 to drive the optical scanning mechanism 10 to operate; specifically, the information processing circuit 13 includes a timing unit 132, a first preamplifier unit 131, a second preamplifier unit 134, a clock unit 135, a logic control / calculation unit 136, a RAM unit 137, a radio frequency signal transceiver unit 138, an interface unit 139 and a driving unit 133, wherein the first preamplifier unit 131, the second preamplifier unit 134, the clock unit 135, and the logic control / calculation unit 136 are all connected to the timing unit 132.

[0064] Specifically, in the present embodiment, two photodetectors are used to perform touch positioning of the display screen, so the timing unit 132 includes a first timer 1321, a second timer 1322, a third timer 1323 and a fourth timer 1324; wherein the first timer 1321 is connected to the first preamplifier unit 131 to obtain the time equivalent of one rotation of the light beam; the second timer 1322 is connected to the second preamplifier unit 134 to obtain the first time equivalent of the light beam from the zero-crossing detection unit 11 to the range positioning unit 12; the third timer 1323 is connected to the logic control / calculation unit 136 to obtain the second time equivalent of the light beam from the zero-crossing detection unit 11 to the second preamplifier unit 134 corresponding to another photodetector; the fourth timer 1324 is connected to the logic control / calculation unit 136 to obtain the third time equivalent of the light beam from the zero-crossing detection unit 11 to the touch member.

[0065] The input end of the first preamplifier unit 131 is connected to the zero-crossing detection unit 11, and the output end is connected to the timing unit 132, so as to receive the photoelectric pulse sent by the zero-crossing detection unit 11 when detecting the light spot on the light beam trajectory, and then amplify the photoelectric pulse and transmit it to the timing unit 132 to start / end the first timer 1321, and then obtain the time equivalent of one rotation of the light beam through the accumulated time of the first timer 1321.

[0066] The input end of the second preamplifier unit 134 is connected to the range positioning unit 12, and the output end is connected to the second timer 1322, so as to receive the photoelectric pulse sent by the range positioning unit 12 when the light spot on the light beam trajectory is detected, and then the photoelectric pulse is amplified and processed, and the second timer 1322 is controlled to stop timing. The accumulated time of the second timer 1322 is the first time equivalent of the light scanning. By substituting the first time equivalent into the formula, the corresponding angular radians between the zero-crossing detection unit 11, the light beam reflection point on the optical element 103 and the range positioning unit 12 can be calculated. The calculation formula of the angular radians is as follows:

[0067]

[0068] In formula (1), t is the time equivalent, and t0 is the time equivalent of one rotation of the light beam.

[0069] The first output end of the clock unit 135 is connected to the timing unit 132 to provide a timing pulse; the second output end is connected to the logic control / calculation unit 136 to provide a timing clock.

[0070] Furthermore, one end of the driving unit 133 is connected to the motor 102 and the light source 101 , and the other end is connected to the logic control / computing unit 136 , and the logic control / computing unit drives the motor 102 and the light source 101 to operate through the driving unit 133 .

[0071] The RAM unit 137, the RF signal transceiver unit 138 and the interface unit 139 are all connected to the logic control / computation unit 136, wherein the RAM unit 137 is used to cache the control process data of the logic control / computation unit 136, the RF signal transceiver unit 138 communicates with the touch element by radio frequency, and the interface unit 139 is connected to the main computer of the display screen to send the acquired touch element coordinate position to the main computer.

[0072] The radio frequency signal transceiver unit 138 is used to receive the photoelectric pulse sent when the touch member detects the light spot on the light beam trajectory, and controls the fourth timer 1324 to stop timing through the logic control / calculation unit 136. The accumulated time of the third timer 1323 is the third time equivalent of the light scanning. By substituting the third time equivalent into formula (1), the corresponding angular radians between the zero-crossing detection unit 11, the light beam reflection point on the optical element 103 and the touch member can be calculated.

[0073] The logic control / calculation unit 136 is also used to receive the photoelectric pulse sent by the range positioning unit 12 of another photodetector when detecting a light spot on the light beam trajectory, and control the third timer 1323 to stop timing. The accumulated time of the third timer 1323 is the second time equivalent of the light scanning. By substituting the second time equivalent into formula (1), the corresponding angular radians among the zero-crossing detection unit 11, the light beam reflection point on the optical element 103 and the range positioning unit 12 of another photodetector can be calculated.

[0074] See also Figure 2 As shown, this embodiment also provides a method for realizing touch positioning of a display screen using the above-mentioned photoelectric detector, which specifically includes the following steps:

[0075] For the image pixel area of ​​the display, the first photodetector and the second photodetector are alternately used to perform light beam scanning of two coordinate systems. Before calculating the coordinate value of the corresponding light point of the touch member on the display screen, it also includes: obtaining a pixel resolution value of the image pixel area, determining the length equivalent of the line between the two range positioning units 12 based on the pixel resolution value, and obtaining the angle between the line between the two range positioning units 12 and a frame of the touch area. It can be understood that, as a preferred embodiment, in order to facilitate the calculation of the coordinates of the touch member, the two range positioning units 12 are respectively set at the first pixel point and the last pixel point of the first row of the image pixel area. For example, if the pixel resolution value obtained is 1920 pixels long and 1080 pixels wide, then the length equivalent of the line between the two range positioning units 12 is 1920 pixels; at the same time, the line between the light beam incident points on the optical elements 103 of the first photodetector and the second photodetector is parallel to the line between the two range positioning units 12.

[0076] It is understandable that according to the trigonometric theorem, the angles of at least two angles and any side of the triangle need to be obtained in order to calculate the length and height of each side of the triangle, and then calculate the coordinates of each angle (point). Therefore, in this embodiment, the first photodetector and the second photodetector are used alternately to scan the light beam. After the first photodetector detects, the first angle-related parameter is obtained; after the second photodetector is started to detect, the second angle-related parameter is obtained; it is understandable that the wavelengths of the light beams emitted by the two photodetectors in this embodiment are the same. Therefore, in order to avoid the photodetector being unable to distinguish where the photoelectric pulse is emitted, the two photodetectors are controlled to detect alternately.

[0077] Specifically, the two coordinate systems include a first coordinate system generated by a light beam trajectory emitted by the optical scanning mechanism 10 of the first photodetector passing through the zero detection unit 11, the range positioning unit 12, the touch member, and each light spot of the range positioning unit 12 of the second photodetector, and a second coordinate system generated by a light beam trajectory emitted by the optical scanning mechanism 10 of the second photodetector passing through the zero detection unit 11, the range positioning unit 12, the touch member, and each light spot of the range positioning unit 12 of the first photodetector;

[0078] See also Figure 3 As shown, the time taken by the timing unit 132 for the light beam trajectory to pass through the zero detection unit 11 to each of the above light spots is accumulated to obtain the time equivalent corresponding to each light spot, thereby determining the angular radian of the constant speed rotation of the light beam; specifically, it includes:

[0079] When the light beam emitted by the first photodetector reaches the zero-crossing detection unit 11, the zero-crossing detection unit 11 generates a photoelectric pulse and sends it to the timing unit 132, starting each timer to start timing;

[0080] When the light beam reaches the range positioning unit 12, the range positioning unit 12 generates a photoelectric pulse and sends it to the timing unit 132, controls the second timer 1322 to stop timing, and obtains the first time equivalent t1 of the angular radian between the zero-crossing detection unit 11 and the range positioning unit 12;

[0081] When the light beam reaches the touch element, the touch element generates a photoelectric pulse and sends it to the timing unit 132, controls the fourth timer 1324 to stop timing, and obtains a third time equivalent t3 of the angle radian between the zero-crossing detection unit 11 and the touch element;

[0082] When the light beam reaches the range positioning unit 12 of the second photodetector, the range positioning unit 12 generates a photoelectric pulse to the timing unit 132 of the first photodetector, controls the third timer 1323 to stop timing, and obtains the second time equivalent t2 of the angular radian between the zero-crossing detection unit 11 and the range positioning unit 12;

[0083] When the light beam rotates one circle and reaches the zero-crossing detection unit 11 of the first photodetector, the zero-crossing detection unit 11 generates a photoelectric pulse and sends it to the timing unit 132, controls the first timer 1321 to stop timing, and obtains the time equivalent t0 of one light scanning circle;

[0084] Furthermore, after obtaining the time equivalent t0, the following steps are also included:

[0085] Read and cache the data of the first timer 1321, the second timer 1322, the third timer 1323 and the fourth timer 1324, and reset the first timer 1321, the second timer 1322, the third timer 1323 and the fourth timer 1324; control the ongoing photodetector to stop beam emission and start another photodetector.

[0086] Specifically, the formula for calculating the angle in radians is as follows:

[0087]

[0088] In formula (1), t is the time equivalent, and t0 is the time equivalent of one light scan.

[0089] Further, the first coordinate and the second coordinate are integrated. The integration result is shown in Figure 4 As shown; the coordinate value of the light point corresponding to the touch element on the display screen is calculated based on the trigonometric function.

[0090] The following is an explanation of the method of photoelectric touch positioning using the optimal embodiment. It should be noted that, in the optimal embodiment, the line between the two range positioning units 12 is parallel to the line between the incident points of the light beams on the optical element 103 of the first photodetector and the second photodetector, and the length of the line between the two range positioning units 12 is equivalent to the length of the resolution value; the method is specifically as follows:

[0091] See also Figure 4 As shown, the integration result of the two coordinates is shown, and the following parameters are obtained from the geometric diagram: the beam emission point O of the first photodetector and the first zero-crossing detection unit P0, the beam emission point O1 of the second photodetector and the first zero-crossing detection unit P0', the first range positioning unit P1, the touch member P3, the second range positioning unit P2, the time equivalent t1 of the angle ∠P0OP1, the time equivalent t3 of the angle ∠P0OP3, the time equivalent t2 of the angle ∠P0OP2, and the time equivalent t0 of the beam emission point O rotating 2π (360°).

[0092] Substituting the time equivalent t1 and the time equivalent t0 into the formula (1), the angular radian of ∠P0OP1 is obtained; substituting the time equivalent t3 and the time equivalent t0 into the formula (1), the angular radian of ∠P0OP3 is obtained; substituting the time equivalent t2 and the time equivalent t0 into the formula (1), the angular radian of ∠P0OP2 is obtained.

[0093] After obtaining the required parameters, the coordinate values ​​of the touch components are calculated according to trigonometric functions. The specific calculation is as follows:

[0094] ① According to the trigonometric theorem, the vertical spacing OO' between P0P0' and P1P2 is calculated as:

[0095] ∵P0O∥P1O′

[0096] ∴∠P0OP1=∠OP1O′

[0097] ∴OO′=P1O′×tan∠P0OP1 (*-1)

[0098] ② According to the trigonometric theorem, the formula for the length of O′P2 is:

[0099] ∵

[0100] ∴

[0101] Substituting (*-1) into equation, we get:

[0102]

[0103] ③Calculate the length of P1O′:

[0104] ∵P1O′+O′P2=P1P2

[0105] Substitute (*-2) into the equation, and we get:

[0106]

[0107] ∴

[0108] ④Calculate the length of O1′P2:

[0109]

[0110] ∵O1O1′=OO′

[0111] Among them, O1O1′ is a vertical auxiliary line

[0112] Substituting (*-1) into the equation, we get:

[0113] O1O1′=P1O′×tan∠P0OP1 (*-4)

[0114] ∴

[0115] ⑤Calculate the length of O′P1′:

[0116]

[0117] Substituting (*-1) into equation, we get:

[0118]

[0119] ⑥Calculate the length of P2′O1′:

[0120]

[0121] ⑦ Calculate the ratio of X0P1′ and X0P2′

[0122] Y=X0P1′×tan∠X0P1′P3=X0P2′×tan∠X0P2′P3

[0123] ∠X0P1′P3=π-∠P0OP3

[0124] ∠X0P2′P3=π-∠P0′O1P3

[0125] ∴

[0126] ⑧Calculate the length of X0P1′+X0P2′

[0127] X0P1′+X0P2′=P1P2-(P1O′+O′P1′+P2′O1′+O1′P2)

[0128] ⑨Calculate the length of X0P1′

[0129] X0P1′=(X0P1′+X0P2′)×tan(π-∠P0′O1P3) / [tan(π-∠P0′O1P3)+tan(π-∠P0OP3)]

[0130] ⑩Calculate the horizontal coordinate X of point P3

[0131] X=P1O′+O′P1′+X0P1′

[0132] Calculate the ordinate Y of point P3

[0133] Y=X0P1′×tan∠X0P1′P3

[0134] Thus, the coordinate value (X, Y) of the touch member P3 is obtained. It can be understood that the present invention uses two photodetectors to emit light beams from two vertices of the flat display frame. The light beams pass through the zero-crossing detection unit 11, the range positioning unit 12 and the touch member to form two coordinate systems. The coordinate value of the touch member can be calculated using trigonometric functions according to the angular radian of the angle between the zero-crossing detection unit 11, the range positioning unit 12 and the touch member and the light beam emission point, and the length equivalent of P1P2 is the pixel resolution value of the first row of the image pixel area. The calculation steps are simplified and clear; and compared with arranging infrared emitting tubes and infrared receiving tubes on the four sides of the screen to form a horizontally and vertically crossed infrared matrix in one-to-one correspondence, the specific position of the touch object can be detected according to the different shielding of light, which is lower in cost.

[0135] In summary, the photodetector of the present invention emits a light beam through a light source 101, a motor 102, and an optical element 103 fixed at one end of the motor 102, which can avoid a scanning blind spot in the touch area of ​​the display screen, and has low electromagnetic noise and weak electromagnetic interference during use; the photodetector emits a light beam to scan the touch area of ​​the display screen, and the light beam trajectories of the two photodetectors pass through the zero-crossing detection unit 11, the range positioning unit 12, and the touch member to obtain two coordinate systems through the logic control / calculation unit 136; based on the timing unit 132 of the photodetector, the time equivalent of each light spot is obtained, and then the angular radian of the constant speed rotation of the light beam is determined; the first coordinate and the second coordinate are integrated, and the coordinate value of the light spot corresponding to the touch member on the display screen is calculated according to the trigonometric function, that is, touch positioning can be achieved with high precision. In addition, the photodetector provided by the present invention is universal and can be applied to flat-panel displays of different sizes (similar to the display screen of a computer or electronic whiteboard, etc.).

[0136] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A photoelectric detector, characterized in that: include: An optical scanning mechanism (10) for emitting a light beam to scan a touch area of ​​a display screen; An information processing circuit (13) electrically connected to the optical scanning mechanism (10); A detection unit, arranged on one side of the display screen, electrically connected to the information processing circuit (13), and used to detect a light spot on the light beam trajectory of the light scanning mechanism (10); The information processing circuit (13) comprises a timing unit (132), and the timing unit (132) is used to obtain the time equivalent corresponding to the light spot, thereby determining the angular arc of the constant speed rotation of the light beam, and thereby determining the coordinate position corresponding to the light spot detected by the touch element on the display screen; the light scanning mechanism (10) comprises: A light source (101) for generating an incident light beam; an optical element (103) for reflecting the incident light beam; and a motor (102) for driving the optical element (103) to rotate, the motor (102) having a hollow main shaft (1021), the optical element (103) being fixed at one end of the hollow main shaft (1021), the light source (101) being arranged at the other end of the hollow main shaft (1021), the incident light beam passing through the hollow main shaft (1021) and incident on the optical element (103), wherein the optical element (103) is arranged such that when the hollow main shaft (1021) drives the optical element (103) to rotate, the light beam reflected by the optical element (103) remains parallel to the touch area of ​​the display screen; The detection unit comprises at least one zero-crossing detection unit (11) and at least one range positioning unit (12), wherein the zero-crossing detection unit (11) and the range positioning unit (12) are both arranged on the same side of a display screen, and the zero-crossing detection unit (11) is arranged on the same horizontal line of a light beam incident point on the optical element (103) to detect a light spot on a light beam trajectory and determine a start and end point of a light scanning cycle.

2. The photodetector according to claim 1, wherein The information processing circuit (13) further comprises: a first preamplifier unit (131), a second preamplifier unit (134), a clock unit (135), a logic control / calculation unit (136), a RAM unit (137), a radio frequency signal transceiver unit (138), an interface unit (139) and a drive unit (133), wherein: The input end of the first preamplifier unit (131) is connected to the zero-crossing detection unit (11), and the output end is connected to the timing unit (132), so as to obtain the start time of the light scanning through the timing unit (132); The input end of the second preamplifier unit (134) is connected to the range positioning unit (12), and the output end is connected to the timing unit (132), so as to obtain the first time equivalent of the light scanning through the timing unit (132); The first output end of the clock unit (135) is connected to the timing unit (132) to provide a timing pulse; the second output end is connected to the logic control / calculation unit (136) to provide a timing clock; One end of the driving unit (133) is connected to the motor (102) and the light source (101), and the other end is connected to the logic control / calculation unit (136); The RAM unit (137), the radio frequency signal transceiver unit (138) and the interface unit (139) are all connected to the logic control / calculation unit (136), wherein: The RAM unit (137) is used to cache the control process data of the logic control / computation unit (136), the radio frequency signal transceiver unit (138) communicates with the touch element via radio frequency, and the interface unit (139) is connected to the main computer of the display screen.

3. The photodetector according to claim 2, wherein: The timing unit (132) includes a first timer (1321), a second timer (1322), a third timer (1323) and a fourth timer (1324), wherein: The first timer (1321) is connected to the first preamplifier unit (131) to obtain the time equivalent of one rotation of the light beam; The second timer (1322) is connected to the second preamplifier unit (134) to obtain the first time equivalent of the light beam from the zero-crossing detection unit (11) to the range positioning unit (12); The third timer (1323) is connected to the logic control / calculation unit (136) to obtain a second time equivalent of the light beam from the zero-crossing detection unit (11) to the range positioning unit (12) corresponding to another photoelectric detector; The fourth timer (1324) is connected to the logic control / calculation unit (136) to obtain a third time equivalent of the light beam from the zero-crossing detection unit (11) to the touch member.

4. A method for photoelectric touch positioning, applied to the photoelectric detector according to any one of claims 1 to 3, characterized in that: The steps include: For the image pixel area of ​​the display, the first photodetector and the second photodetector are used alternately to perform light beam scanning of two coordinate systems. The two coordinate systems include a first coordinate system generated by a light beam trajectory emitted by a light scanning mechanism (10) of a first photodetector passing through a zero detection unit (11), a range positioning unit (12), a touch member, and light points of the range positioning unit (12) of a second photodetector, and a second coordinate system generated by a light beam trajectory emitted by a light scanning mechanism (10) of a second photodetector passing through a zero detection unit (11), a range positioning unit (12), a touch member, and light points of the range positioning unit (12) of the first photodetector; The time taken for the light beam trajectory to pass through the zero detection unit (11) to each of the above light spots is accumulated by a timing unit (132) to obtain the time equivalent corresponding to each light spot, thereby determining the angular radian of the constant speed rotation of the light beam; The first coordinate and the second coordinate are integrated, and the coordinate value of the light point corresponding to the touch element on the display screen is calculated according to the trigonometric function.

5. The photoelectric touch positioning method according to claim 4, characterized in that: The timing unit (132) accumulates the time from the light beam trajectory passing through the zero detection unit (11) to each of the above light spots, obtains the time equivalent corresponding to each light spot, and then determines the angular radian of the constant speed rotation of the light beam, specifically including: When the light beam emitted by the first photodetector reaches the zero-crossing detection unit (11), the zero-crossing detection unit (11) generates a photoelectric pulse and sends it to the timing unit (132), thereby starting each timer to start timing; When the light beam reaches the range positioning unit (12), the range positioning unit (12) generates a photoelectric pulse and sends it to the timing unit (132), controls the second timer (1322) to stop timing, and obtains a first time equivalent. t 1, and then determining the angular radian between the zero-crossing detection unit (11) and the range positioning unit (12); When the light beam reaches the touch element, the touch element generates a photoelectric pulse which is sent to the timing unit (132), and controls the fourth timer (1324) to stop timing, thereby obtaining a third time equivalent. t 3, and then determining the angular arc between the zero-crossing detection unit (11) and the touch member; When the light beam reaches the range positioning unit (12) of the second photoelectric detector, the range positioning unit (12) generates a photoelectric pulse to the timing unit (132) of the first photoelectric detector, controls the third timer (1323) to stop timing, and obtains a second time equivalent. t 2 and then determining the angular arc between the zero-crossing detection unit (11) and the range positioning unit (12); When the light beam rotates one circle and reaches the zero-crossing detection unit (11) of the first photodetector, the zero-crossing detection unit (11) generates a photoelectric pulse and sends it to the timing unit (132), controlling the first timer (1321) to stop timing, thereby obtaining the time equivalent of one circle of light scanning. t 0; The formula for calculating the angle in radians is as follows: （1） In formula (1), t is the time equivalent, t 0 is the time equivalent of one optical scan.

6. The photoelectric touch positioning method according to claim 5, characterized in that: Getting time equivalent t After 0, the following steps are also included: Read and cache the data of the first timer (1321), the second timer (1322), the third timer (1323) and the fourth timer (1324), and reset the first timer (1321), the second timer (1322), the third timer (1323) and the fourth timer (1324); The photodetector in control stops beam emission and another photodetector is activated.

7. The photoelectric touch positioning method according to claim 6, characterized in that: Before calculating the coordinate value of the light point corresponding to the touch element on the display screen, it also includes: The pixel resolution value of the image pixel area is obtained, and the length equivalent of the line between the two range positioning units (12) is determined based on the pixel resolution value, and the angle between the line between the two range positioning units (12) and a frame of the touch area is obtained.

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