Retro-reflection type photoelectric sensor based on triangulation distance measurement

Abstract

The invention provides a regression reflection type photoelectric sensor based on triangulation ranging, which belongs to the technical field of electronic engineering and comprises a transmitting module, a reflecting module and a receiving module, and the reflecting module, the transmitting module and the receiving module are triangularly arranged; the receiving module comprises a multi-pixel receiving tube and is used for generating an electric signal according to the received light; the control module is respectively connected with the transmitting module and the receiving module and is used for driving the transmitting module to transmit light, determining the intensity and distribution information of the light spots according to the electric signals and determining a detection result according to the intensity and distribution information of the light spots; the detection result at least comprises whether the to-be-detected object exists between the transmitting module and the reflecting module. The beneficial effects of the invention are that based on the triangulation ranging principle, the multi-pixel receiving tube and the reflecting plate are adopted to determine the intensity and distribution information of the light spots so as to determine whether the to-be-measured object exists between the transmitting module and the reflecting module or not, an additional polaroid is not needed, and the method has the advantages of low cost, high reliability, small blind area and the like.

Description

Technical Field

[0001] The present invention relates to the field of electronic engineering technology, and in particular to a regressive reflective photoelectric sensor. Background Art

[0002] The regressive reflective photoelectric sensor is usually composed of a sensor body and a reflector. The sensor body includes a control module and a transmitting end, a transmitting lens, a receiving lens, and a receiving end arranged along the optical path. Its working principle is: the light emitted by the transmitting end is driven by the control module to be focused by the transmitting lens and projected onto the reflector, and then reflected by the reflector to the receiving lens, and the receiving lens focuses the light to the receiving end, thereby detecting whether there is an object to be measured between the sensor body and the reflector.

[0003] Blind area is one of the important indicators for evaluating regressive reflective photoelectric sensors. Generally, if there is an object to be measured between the sensor body and the reflector, the light reflected back by the reflector cannot reach the receiving tube at the transmitting end, thus triggering the regressive reflective photoelectric sensor.

[0004] However, when the object to be measured is close to the sensor body within a certain distance range, the intensity of the diffuse reflection light generated by the surface of the object to be measured is large enough, so that even if the object to be measured is blocked between the sensor body and the reflector, the receiving tube can still receive the light diffusely reflected back to the sensor by the object to be measured. If the intensity of the diffuse reflection light exceeds the trigger threshold of the sensor, it will cause the sensor to determine that the light from the reflector is received, rather than being blocked by the object, resulting in a misjudgment of the sensor. Therefore, this distance range is the blind spot of the retro-reflective photoelectric sensor.

[0005] In order to reduce the blind area, existing retro-reflective photoelectric sensors usually use polarizers to distinguish the light reflected by the reflector from the diffusely reflected light generated by the surface of the object to be measured. Figure 1 As shown, by installing a 0-degree polarizer 100 in the transmitting circuit and a 90-degree polarizer 101 in the receiving circuit, a special reflector 102 has multiple sets of triangular cones or other optical materials on its surface to fold the emitted light by 90 degrees. Figure 1 As shown in (a), only the light reflected back to the sensor by the reflector 102 can reach the receiving tube through the 90-degree polarizer 101 of the receiving circuit. Figure 1 As shown in (b), the diffuse reflected light generated by the surface of the object 103 to be measured between the sensor body and the reflector 102 does not pass through 90 degrees of deflection, so most of it cannot reach the receiving tube of the sensor. Even if the object 103 to be measured is very close to the sensor, the light diffusely reflected back to the sensor cannot pass through the 90-degree polarizer, resulting in the received light intensity not reaching the threshold and not triggering the sensor, thereby greatly reducing the blind area of ​​the sensor.

[0006] However, this polarizer design also introduces higher costs and manufacturing complexity, and places higher requirements on both the polarizer and the reflector. If the quality of the polarizer or reflector is poor, since the combination of the polarizer and the reflector cannot achieve a 0-degree deflection of the emitted light, the light received by the receiving tube is a 90-degree deflection of the emitted light of the transmitting tube, then diffuse reflected light will enter the receiving tube, resulting in a large blind area for the sensor. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a regression-reflective photoelectric sensor based on triangulation ranging.

[0008] The technical problem solved by the present invention can be achieved by adopting the following technical solutions:

[0009] A regression-reflective photoelectric sensor based on triangulation distance measurement, comprising:

[0010] A transmitting module, a reflecting module and a receiving module, wherein the reflecting module, the transmitting module and the receiving module are arranged in a triangle;

[0011] The receiving module includes a multi-pixel receiving tube for generating an electrical signal according to the received light;

[0012] a control module, connected to the transmitting module and the receiving module respectively, and used to drive the transmitting module to emit light, and determine the intensity and distribution information of the light spot according to the electrical signal, and determine the detection result according to the intensity and distribution information of the light spot;

[0013] The detection result at least includes whether there is an object to be detected between the transmitting module and the reflecting module.

[0014] Preferably, the transmitting module comprises:

[0015] An emitting end, the emitting end is used to emit light under the driving action of the control module;

[0016] The emitting lens is arranged between the emitting end and the reflecting module, and is used for focusing the light emitted by the emitting end through the emitting lens and then emitting it toward the reflecting module.

[0017] Preferably, the emitting lens is a plano-convex lens, the plane of the emitting lens is arranged toward the emitting end, and the convex surface of the emitting lens is arranged toward the reflecting module.

[0018] Preferably, the reflection module comprises a reflection plate, and a surface of the reflection plate facing the emission module is serrated.

[0019] Preferably, the receiving module further includes:

[0020] A receiving lens is located between the multi-pixel receiving tube and the reflection module.

[0021] Preferably, the receiving lens is a plano-convex lens, the plane of the receiving lens is arranged toward the multi-pixel receiving tube, and the convex surface of the receiving lens is arranged toward the reflection module.

[0022] Preferably, the control module further includes:

[0023] A light spot centroid position determination unit, used to determine the light spot centroid position according to the intensity and distribution information of the light spot;

[0024] The distance measuring unit is connected to the light spot centroid position determining unit and is used to determine the distance between the object to be measured and the regressive reflective photoelectric sensor according to the light spot centroid position.

[0025] Preferably, the control module comprises:

[0026] A light intensity variation determination unit, used to determine the light intensity variation of the light spot relative to a preset light intensity threshold;

[0027] A first judging unit, connected to the light intensity variation determination unit, is used to judge whether the light intensity variation exceeds a preset intensity threshold, and when the light intensity variation exceeds the preset intensity threshold, output a first detection result of judging that there is an object to be detected between the transmitting module and the reflecting module;

[0028] The detection results include the first detection result.

[0029] Preferably, the control module further includes:

[0030] A second judgment unit is used to judge whether the change of the light spot position exceeds a preset position threshold when the light intensity change does not exceed the preset intensity threshold, and output a second detection result of determining whether there is an object to be detected between the transmitting module and the reflecting module when the light spot position change exceeds the preset position threshold;

[0031] The detection result includes the second detection result.

[0032] Preferably, it also includes:

[0033] A power module connected to the control module;

[0034] The communication module is connected to the power module.

[0035] The advantages or beneficial effects of the technical solution of the present invention are:

[0036] The present invention is based on the principle of triangulation ranging. It uses a multi-pixel receiving tube and a reflector to determine the intensity and distribution information of the light spot, and then determines whether there is an object to be measured between the transmitting module and the reflecting module. There is no need to use an additional polarizing plate. It has the advantages of low cost, high reliability, and a small blind area. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the principle of a retro-reflective photoelectric sensor using a polarizer in the prior art;

[0038] Figure 2 It is a structural block diagram of a regression reflective photoelectric sensor in a preferred embodiment of the present invention;

[0039] Figure 3 A structural block diagram of a transmitting module and a receiving module in a preferred embodiment of the present invention;

[0040] Figure 4 This is a structural block diagram of a control module in a preferred embodiment of the present invention;

[0041] Figure 5 This is a structural block diagram of a control module in a preferred embodiment of the present invention;

[0042] Figure 6 This is a structural block diagram of a control module in a preferred embodiment of the present invention;

[0043] Figure 7 It is a structural block diagram of a regression reflective photoelectric sensor in a preferred embodiment of the present invention;

[0044] Figure 8 This is a schematic diagram of the optical path when there is no object to be measured between the sensor and the reflector in a preferred embodiment of the present invention;

[0045] Fig. 9 Schematic diagram of the optical path when there is an object to be measured between the sensor and the reflector in a preferred embodiment of the present invention;

[0046] Fig.10 This is a schematic diagram of the optical path when the object to be measured is close to the sensor in a preferred embodiment of the present invention;

[0047] Fig.11 This is a schematic diagram of the optical path when the object to be measured between the sensor and the reflector is a mirror or a highly reflective object in a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0050] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0051] See also Figure 2 In a preferred embodiment of the present invention, based on the above problems existing in the prior art, a regression reflective photoelectric sensor based on triangulation distance measurement is provided, comprising:

[0052] A transmitting module 1, a reflecting module 2 and a receiving module 3, wherein the reflecting module 2, the transmitting module 1 and the receiving module 3 are arranged in a triangle;

[0053] The receiving module 3 includes a multi-pixel receiving tube 31, which is used to generate an electrical signal according to the received light;

[0054] The control module 4 is connected to the transmitting module 1 and the receiving module 3 respectively, and is used to drive the transmitting module 1 to transmit light, and determine the intensity and distribution information of the light spot according to the electrical signal, and determine the detection result according to the intensity and distribution information of the light spot;

[0055] The detection result at least includes whether there is an object to be detected between the transmitting module 1 and the reflecting module 2.

[0056] Specifically, the regressive reflective photoelectric sensor provided in the embodiment of the present invention includes a transmitting module 1, a reflecting module 2, a receiving module 3 and a control module 4. By simultaneously measuring the distribution of the light spot intensity and the light spot position, it can accurately determine whether there is an object to be measured between the sensor and the reflecting plate 21. There is no need to use a polarizing film, thereby avoiding the misjudgment situation that may be caused in the existing regressive reflective photoelectric sensor. Even if the object is located relatively close, the misjudgment problem of the sensor can be avoided. A regressive reflective photoelectric sensor with a small blind area can be realized without using a polarizing film, thereby improving the performance of the sensor.

[0057] Furthermore, the multi-pixel receiving tube 31 can output the voltage of the received light on the receiving tube of each pixel to form the above-mentioned electrical signal, and calculate the light spot intensity and the center of mass position of the light spot on each receiving tube based on this, so as to determine whether there is an object to be measured between the sensor and the reflector 21.

[0058] When an object to be measured is blocked between the sensor and the reflector 21 , the distance between the object to be measured and the sensor can be further deduced according to the light spot intensity and the position of the light spot centroid based on the triangulation distance measurement principle.

[0059] When there is an object to be detected between the sensor and the reflective plate 21 , the detection result may further include the distance between the object to be detected and the sensor.

[0060] As a preferred embodiment, wherein Figure 3 As shown, the transmitting module 1 includes:

[0061] The transmitting end 11 is used to emit light under the driving action of the control module;

[0062] The transmitting lens 12 is disposed between the transmitting end 11 and the reflecting module 2, and is used for focusing the light emitted by the transmitting end 11 through the transmitting lens 12 and then emitting it toward the reflecting module.

[0063] Specifically, the transmitting module 1 includes a transmitting end 11 and a transmitting lens 12 which are arranged in sequence. The transmitting end 11 and the reflecting module 2 are arranged opposite to each other.

[0064] In this embodiment, the transmitting end 11 may include a light emitting device, and the light emitting device may include one or more light emitting devices.

[0065] If there are multiple light-emitting devices, the multiple light-emitting devices can be arranged in a specific manner to form an emission array to form a specific form of light source.

[0066] As a preferred embodiment, wherein Figures 8 to 11 As shown, the emitting lens 12 is a plano-convex lens, the plane of the emitting lens 12 is arranged toward the emitting end 11 , and the convex surface of the emitting lens 12 is arranged toward the reflecting module 2 .

[0067] Specifically, one side of the emitting lens 12 is a plane and the other side is a convex surface. The plane faces the emitting end 11 and the convex surface faces the reflecting module 2. The convex surface focuses the light to reduce light scattering so that the light can propagate in the expected direction, thereby ensuring that the light can be accurately projected onto the reflecting module 2, thereby improving the directionality and intensity of the light.

[0068] As a preferred embodiment, wherein Figures 8 to 11 As shown, the reflection module 2 includes a reflection plate 21 , and a surface of the reflection plate 21 facing the emission module 1 is serrated.

[0069] Specifically, the surface of the reflector 102 has a plurality of triangular pyramids or other optical materials, presenting a sawtooth shape, so as to fold the light emitted by the emission module 1 by 90 degrees.

[0070] As a preferred embodiment, wherein Figure 3As shown, the receiving module 3 also includes:

[0071] The receiving lens 32 is located between the multi-pixel receiving tube 31 and the reflection module 2 .

[0072] Specifically, the receiving module 3 includes a receiving end and a receiving lens 32 arranged in sequence. The receiving end of the receiving module 3 adopts the above-mentioned multi-pixel receiving tube 31 to receive the voltage of light on the receiving tube of each pixel, and deduce the light spot intensity, the center of mass position of the light spot and the measured distance on each pixel receiving tube based on this.

[0073] In this embodiment, the multi-pixel receiving tube 31 can be implemented by a multi-pixel CMOS distance measurement sensor chip.

[0074] It should be noted that the multi-pixel CMOS distance measuring sensor chip may adopt an existing chip, such as the programmable photoelectric sensor shown in CN114440943A, but is not limited thereto and the present invention does not make any limitation thereto.

[0075] As a preferred embodiment, wherein Figures 8 to 11 As shown, the receiving lens 32 is a plano-convex lens, the plane of the receiving lens 32 is arranged toward the multi-pixel receiving tube 31 , and the convex surface of the receiving lens 32 is arranged toward the reflection module 2 .

[0076] Specifically, one side of the receiving lens 32 is a plane and the other side is a convex surface, the plane faces the multi-pixel receiving tube 31, and the convex surface faces the reflecting module 2. When the light reflected from the reflecting plate 21 or the light diffusely reflected from the surface of the obstructed object to be measured enters the receiving lens 32 through the convex surface, the light is focused and then projected from the plane onto the multi-pixel receiving tube 31.

[0077] After receiving the light, the multi-pixel receiving tube 31 converts it into an electrical signal, which is then processed and analyzed by the control module 4 to measure the reflected light intensity, the center of mass position of the light spot, and other information, and to determine whether there is an object between the sensor and the reflector 21.

[0078] As a preferred embodiment, wherein Figure 4 As shown, the control module 4 also includes:

[0079] A light spot centroid position determination unit 41, used to determine the light spot centroid position according to the intensity and distribution information of the light spot;

[0080] The distance measuring unit 42 is connected to the light spot centroid position determining unit 41 and is used to determine the distance between the object to be measured and the regressive reflective photoelectric sensor according to the light spot centroid position.

[0081] Specifically, the centroid position of the light spot is the center point of the light spot intensity distribution, representing the geometric center of the light spot on the multi-pixel receiving tube.

[0082] Furthermore, the light spot centroid position determination unit 41 may calculate the light spot centroid position by weighted average method. Specifically, the weighted sum is taken according to the intensity of light received by all pixel receiving tubes, and then divided by the total intensity value to calculate the centroid position coordinates of the light spot.

[0083] According to the position of the centroid of the light spot, the sensor can measure the distance of the object to be measured based on the principle of triangulation.

[0084] As a preferred embodiment, wherein Figure 5 As shown, the control module 4 includes:

[0085] A light intensity variation determination unit 43, used to determine a light intensity variation of the light spot intensity relative to a preset light intensity threshold;

[0086] The first judging unit 44 is connected to the light intensity variation determining unit 43, and is used to judge whether the light intensity variation exceeds a preset intensity threshold, and when the light intensity variation exceeds the preset intensity threshold, output a first detection result of determining that there is an object to be detected between the transmitting module 1 and the reflecting module 2;

[0087] The detection results include a first detection result.

[0088] Specifically, an eight-pixel receiving tube is taken as an example below, but the present invention is not limited thereto and does not make any limitation thereto.

[0089] like Figure 8 A schematic diagram of the optical path when there is no object to be measured between the sensor and the reflector is shown. Figure 8 In FIG, A1 is the intensity and distribution information of the light spot on the eight-pixel receiving tube when there is no object to be measured blocking it.

[0090] Specifically, when there is no object blocking the light, the intensity and position of the light spot received by the sensor will not change, or even if they change, the amplitude of the change is less than the corresponding set threshold, and the sensor can determine that there is no object to be measured between the sensor and the reflector 21.

[0091] like Fig. 9 It shows a schematic diagram of the optical path when there is an object to be measured (such as a non-mirror or non-highly reflective object B1) between the sensor and the reflector and the distance is far (ie, outside the blind area of ​​the existing regressive reflective photoelectric sensor). Fig. 9 In FIG. 1 , A2 is the intensity and distribution information of the light spot on the eight-pixel receiving tube when the object to be measured is blocked and the distance is far.

[0092] Specifically, compared to no object blocking, when there is an object (such as a non-mirror or non-high-reflective object) blocking the sensor and the reflector 21, the light intensity received by the sensor will be reduced when the diffusely reflected light generated by the surface of the non-mirror or high-reflective object reaches the sensor receiving end.

[0093] Therefore, when it is detected that the light intensity change exceeds the preset intensity threshold, or the light intensity decrease exceeds the preset intensity threshold, the sensor can determine that the change is caused by the object to be measured blocking between the sensor and the reflector 21. Therefore, it is determined that there is an object to be measured between the sensor and the reflector 21.

[0094] As a preferred embodiment, wherein Figure 6 As shown, the control module 4 also includes:

[0095] The second judgment unit 45 is used to judge whether the change of the light spot position exceeds the preset position threshold when the light intensity change does not exceed the preset intensity threshold, and output a second detection result of determining whether there is an object to be detected between the transmitting module 1 and the reflecting module 2 when the change of the light spot position exceeds the preset position threshold;

[0096] The detection result includes a second detection result.

[0097] Specifically, Fig.10 It shows a schematic diagram of the optical path when there is an object to be measured (such as a non-mirror or non-highly reflective object B1) between the sensor and the reflector and the distance is relatively close (ie, located in the blind area of ​​the existing regressive reflective photoelectric sensor). Fig.10 Among them, A3 is the intensity and distribution information of the light spot on the eight-pixel receiving tube when the object to be measured is blocked and the distance is relatively close.

[0098] If a change in the intensity of the light spot is detected, but the change in light intensity does not exceed the preset intensity threshold, but the position of the centroid of the light spot has changed, and the change in the position of the centroid of the light spot exceeds the preset position threshold, the sensor can calculate the distance of the object to be measured from the sensor based on the principle of triangulation, thereby determining that there is an object to be measured between the sensor and the reflector 21. Even if the object is close, the sensor's misjudgment problem can be avoided, and a regression-reflective photoelectric sensor with a small blind area can be realized without a polarizer.

[0099] In this embodiment, the closer the object to be measured is to the sensor, the greater the change in the position of the centroid of the light spot is, and the more accurate the distance measurement result is.

[0100] like Fig.11 It shows a schematic diagram of the optical path when there is an object to be measured (such as a mirror or a highly reflective object B2) between the sensor and the reflector. Fig.11 Among them, A4 is the intensity and distribution information of the light spot on the eight-pixel receiving tube when it is blocked by a mirror or a highly reflective object.

[0101] Specifically, when the object is a mirror or a highly reflective object, the sensor of the embodiment of the present invention can record the intensity and position of the light spot at the same time. Since the change in light intensity or the change in the light spot position due to mirror reflection exceeds the corresponding set threshold, the sensor can still determine that there is an object between the sensor and the reflector 21.

[0102] In most cases, based on the change in the light spot position or the change in light intensity exceeding a certain set threshold, the sensor can distinguish whether the light is reflected by a reflector or diffusely reflected light generated by a mirror or a highly reflective object surface, avoiding the problem of false triggering caused by diffuse reflection and improving the reliability of the sensor.

[0103] The regressive reflective photoelectric sensor of the embodiment of the present invention can simultaneously monitor the centroid position of the light spot, the light received by each pixel receiving tube, and the ratio of the light intensity received by each pixel receiving tube, and then measure the distance between the sensor and the object to be measured based on the principle of triangulation. By combining different data, it is determined whether the object is located between the sensor and the reflector 21, and the triggering conditions of the sensor are further optimized to adapt to different application requirements.

[0104] As a preferred embodiment, wherein Figure 7 As shown, it also includes:

[0105] A power module 5 connected to the control module 4;

[0106] The communication module 6 is connected to the power module 5 .

[0107] Specifically, the regressive reflective photoelectric sensor of the embodiment of the present invention may also include a power module 5 and a communication module 6. The power module 5 is used to power the sensor, and the communication module 6 is used to communicate data with external devices, including but not limited to receiving instructions, feedback of data, etc.

[0108] The embodiment of the present invention realizes a regressive reflective photoelectric sensor that does not require a polarizer and has a small blind area, and its working process is as follows:

[0109] Set up the sensor and the reflector 21: In the initial setting stage, fix the sensor and the reflector 21 at the installation position so that the light spot of the sensor faces the reflector 21. At this time, the optical path diagram of the sensor is as follows: Figure 8 shown.

[0110] Sensor self-adjustment: After the sensor and the reflector 21 are installed, the sensor is operated in a normal state by adjusting the emission light intensity and the sensor channel gain. Specifically, the operator can automatically adjust the emission light intensity and the sensor channel gain by pressing the sensor's self-adjustment button or by communication methods such as inductance / Hall adjustment, teach in line or IO-LINK, so that the sensor voltage meets the working adjustment to ensure that the reflected light intensity reflected from the reflector 21 measured by the sensor reaches a certain threshold.

[0111] After completing the initial setting of the sensor and ensuring that the sensor works in a normal state, the sensor records the position of the reflected light spot on the multi-pixel receiving tube 31 and the intensity on each pixel receiving tube under the control of the microprocessor of the control module 4. These data are used to calculate the intensity ratio on each pixel receiving tube and the centroid position of the light spot, and then the distance between the reflector 21 and the sensor can be measured.

[0112] The sensor continuously measures the received light and monitors whether the light intensity of each pixel receiving tube changes and whether the position of the centroid of the light spot changes, thereby determining whether there is an object between the sensor and the reflector 21 .

[0113] If there is any object to be measured between the sensor and the reflector 21 , the light intensity of each pixel receiving tube, the centroid position of the light spot and the distance from the object to be measured to the sensor measured by the sensor will change, so that the sensor can determine whether there is an object to be measured between the sensor and the reflector 21 .

[0114] The sensor makes the following determinations:

[0115] When it is detected that the light intensity change does not exceed the preset intensity threshold, and the change of the centroid position of the light spot does not exceed the preset position threshold, it can be determined that there is no object to be measured blocking between the sensor and the reflector 21. Figure 8 shown.

[0116] When the light intensity variation is detected to exceed the preset intensity threshold, it can be determined that there is an obstruction between the sensor and the reflector 21. Fig. 9 A non-mirror or non-highly reflective object at a distance is shown. The change in light intensity here can be a decrease in light intensity or an increase in light intensity.

[0117] When it is detected that the light intensity change does not exceed the preset intensity threshold, but the change of the light spot centroid position exceeds the preset position threshold, it can be determined that there is an object to be detected between the sensor and the reflector 21. Fig.10 A non-specular or non-highly reflective object at a closer distance, such as Fig.11 Mirrored or highly reflective objects as shown.

[0118] Therefore, by comprehensively considering the position of the light spot and the data of the light intensity and utilizing the triangulation ranging algorithm, the retro-reflective sensor of the present invention does not require a polarizing film to reduce the sensor blind area of ​​retro-reflection, but instead determines the output of the sensor by simultaneously judging the position of the light spot of the reflected light (the distance between the sensor and the object) and the light intensity of the reflected light.

[0119] Furthermore, if the regressive reflective photoelectric sensor of the embodiment of the present invention still uses a polarizer, since the sensor of the embodiment of the present invention can simultaneously monitor the light intensity and the centroid position of the light spot, it can comprehensively judge whether there is an object blocking the light based on the changes in the light intensity and the centroid position of the light spot. Therefore, the sensor's requirements for the quality / installation / optical path of the polarizer are reduced.

[0120] If the same quality polarizer is used, the sensor will be more reliable when measuring high-brightness / high-reflection / specular-reflection objects.

[0121] The regressive reflective photoelectric sensor of the embodiment of the present invention has the advantages of low cost, high reliability, small blind area, etc. It can replace the existing regressive reflective photoelectric sensor with polarizer and is widely used in industrial automation control.

[0122] The advantages or beneficial effects of adopting the above technical solution are: the present invention is based on the principle of triangulation ranging, and uses a multi-pixel receiving tube and a reflector to determine the intensity and distribution information of the light spot, and then determines whether there is an object to be measured between the transmitting module and the reflecting module. There is no need to use an additional polarizing plate, and has the advantages of low cost, high reliability, and small blind area.

[0123] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of this specification and illustrations should be included in the protection scope of the present invention.

Claims

1. A regressive reflective photoelectric sensor based on triangulation, characterized in that: include: A transmitting module, a reflecting module and a receiving module, wherein the reflecting module, the transmitting module and the receiving module are arranged in a triangle; The receiving module includes a multi-pixel receiving tube for generating an electrical signal according to the received light; a control module, connected to the transmitting module and the receiving module respectively, and used to drive the transmitting module to emit light, and determine the intensity and distribution information of the light spot according to the electrical signal, and determine the detection result according to the intensity and distribution information of the light spot; The detection result at least includes whether there is an object to be detected between the transmitting module and the reflecting module.

2. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 1, characterized in that: The transmitting module comprises: An emitting end, the emitting end is used to emit light under the driving action of the control module; The emitting lens is arranged between the emitting end and the reflecting module, and is used for focusing the light emitted by the emitting end through the emitting lens and then emitting it toward the reflecting module.

3. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 2, characterized in that: The emitting lens is a plano-convex lens, the plane of the emitting lens is arranged toward the emitting end, and the convex surface of the emitting lens is arranged toward the reflecting module.

4. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 1, characterized in that: The reflection module comprises a reflection plate, and a surface of the reflection plate facing the emission module is serrated.

5. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 1, characterized in that: The receiving module also includes: A receiving lens is located between the multi-pixel receiving tube and the reflection module.

6. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 5, characterized in that: The receiving lens is a plano-convex lens, the plane of the receiving lens is arranged toward the multi-pixel receiving tube, and the convex surface of the receiving lens is arranged toward the reflection module.

7. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 1, characterized in that: The control module also includes: A light spot centroid position determination unit, used to determine the light spot centroid position according to the intensity and distribution information of the light spot; The distance measuring unit is connected to the light spot centroid position determining unit and is used to determine the distance between the object to be measured and the regression reflective photoelectric sensor according to the light spot centroid position.

8. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 1, characterized in that: The control module comprises: A light intensity variation determination unit, used to determine the light intensity variation of the light spot relative to a preset light intensity threshold; A first judging unit, connected to the light intensity variation determination unit, is used to judge whether the light intensity variation exceeds a preset intensity threshold, and when the light intensity variation exceeds the preset intensity threshold, output a first detection result of judging that there is an object to be detected between the transmitting module and the reflecting module; The detection results include the first detection result.

9. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 8, characterized in that: The control module also includes: A second judgment unit is used to judge whether the change of the light spot position exceeds a preset position threshold when the light intensity change does not exceed the preset intensity threshold, and output a second detection result of determining whether there is an object to be detected between the transmitting module and the reflecting module when the light spot position change exceeds the preset position threshold; The detection result includes the second detection result.

10. The regressive reflective photoelectric sensor based on triangulation distance measurement according to claim 1, characterized in that: Also includes: A power module connected to the control module; The communication module is connected to the power module.

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