Diffuse reflection safety grating

Abstract

The invention discloses a diffuse reflection safety grating, which comprises a control module, a driving module, a first emitter, a second emitter, a receiver, a lens module, a first object to be measured and a second object to be measured, and is characterized in that the control module is used for emitting a driving control signal; the driving module is used for driving the first transmitter or the second transmitter to transmit an optical signal according to the driving control signal, so that the first transmitter transmits the optical signal to a first to-be-measured object, or the second transmitter transmits the optical signal to a second to-be-measured object; the lens module is used for receiving a first optical signal reflected by a first to-be-measured object or receiving a second optical signal emitted by a second to-be-measured object; and the receiver is used for receiving the first optical signal or the second optical signal. Therefore, the bijection distance is farther, the unilateral diffuse reflection grating is easier to install and deploy, light focusing is not needed, the device can be used through unilateral installation, and the application range of the device is widened.

Description

Technical Field

[0001] The invention relates to the field of optical technology, in particular to a diffuse reflection safety grating. Background Art

[0002] The diffuse reflection grating module in the prior art includes a transmitting device and a receiving device, and the transmitting device and the receiving device are a one-to-one module, the cost is relatively high, and the integration is also relatively general. In addition, the diffuse reflection grating at close range is not even optically designed with an optical lens. The existing diffuse reflection grating generally adopts an off-axis transceiver system. If laser transceiver is used, there will be a blind spot in close-range detection. If infrared LED is used for transmission and phototransistor is used for receiving signals, the peak power requirement for the required response will be very high. How to make the diffuse reflection safety grating detect signals at both close and long distances and improve the accuracy and detection distance of the detected object is a problem that needs to be solved urgently. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a laser diffuse reflection safety grating.

[0004] In a first aspect, the present invention provides a diffuse reflection safety grating, the diffuse reflection safety grating comprising: a control module, a driving module, a first transmitter, a second transmitter, a receiver, a lens module, a first object to be measured and a second object to be measured, the control module is connected to the driving module, and the driving module is respectively connected to the first transmitter, the second transmitter and the receiver, wherein: The control module is used to send a drive control signal; The driving module is used to drive the first emitter or the second emitter to emit a light signal according to the driving control signal, so that the first emitter emits a light signal to the first object to be measured, or the second emitter emits a light signal to the second object to be measured; The lens module is used to receive a first light signal reflected by the first object to be measured, or to receive a second light signal emitted by the second object to be measured; The receiver is used to receive the first optical signal or the second optical signal.

[0005] Optionally, the lens module at least includes a plano-convex lens and a supplementary component, and the supplementary component is attached to the receiving surface of the plano-convex lens.

[0006] Optionally, the supplementary component includes at least any one of a glued prism sheet, a small-sized lens, a diffuse reflection patch or a plastic light guide column.

[0007] Optionally, the lens module is used to deflect light when detecting an object at a close distance, so that the light originally deviated from the receiver is converged into the receiver.

[0008] Optionally, both the first emitter and the second emitter are semiconductor lasers.

[0009] Optionally, the receiver is an APD photodetector.

[0010] Optionally, the control module is a single chip microcomputer or other signal processing module.

[0011] Optionally, the control module is used to send a time-division multiplexed drive control signal.

[0012] Optionally, the control module is further used for: When the distance between the object to be measured and the diffuse reflection safety grating is greater than the preset value, Assuming that the distance between the object to be measured and the diffuse reflection safety grating is L, the distance between the receiver and the transmitter is d, the angle is α, the radius of the plano-convex lens is r, the back focal length of the plano-convex lens is f, and the energy center position of the light spot is s, the following relationship exists: ; ; When s is less than or equal to r, it is determined that the light signal reflected by the measured object is detected.

[0013] Optionally, the control module is further used for: When s is greater than r, it is determined that the light signal reflected by the detected object is less than a preset value.

[0014] The diffuse reflection safety grating provided by the present invention comprises: a control module, a driving module, a first transmitter, a second transmitter, a receiver, a lens module, a first object to be measured and a second object to be measured, wherein the control module is connected to the driving module, and the driving module is respectively connected to the first transmitter, the second transmitter and the receiver, wherein: the control module is used to send a driving control signal; the driving module is used to drive the first transmitter or the second transmitter to emit a light signal according to the driving control signal, so that the first transmitter emits a light signal to the first object to be measured, or the second transmitter emits a light signal to the second object to be measured; the light emitted by the transmitter is collimated, and the divergence angle of the laser is approximately within 1°; the lens module is used to receive the first light signal reflected by the first object to be measured, or receive the second light signal emitted by the second object to be measured; the receiver is used to receive the first light signal or the second light signal. The dual-transmitting and single-receiving laser module adopts a time-division multiplexing transmission scheme, and the single-sided diffuse reflection grating adopts, which is easier to install and deploy, does not require light alignment, and can be used even if it is installed on one side, thereby improving the scope of application of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of a diffuse reflection safety grating structure provided by an embodiment of the present invention; Figure 2 A schematic diagram of another diffuse reflection safety grating provided in an embodiment of the present invention; Figure 3 A schematic diagram of the detection principle provided by an embodiment of the present invention; Figure 4 A schematic diagram of a driving signal provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0016] 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 those skilled in the art without creative work are within the scope of protection of the present invention.

[0017] See also Figure 1 The present invention provides a structural schematic diagram of a diffuse reflection safety grating, which includes a control module 101, a driving module 102, a first transmitter 103, a second transmitter 104, a receiver 105, a lens module 106, a first object to be measured 107 and a second object to be measured 108. The control module 101 is connected to the driving module 102, and the driving module 102 is respectively connected to the first transmitter 103, the second transmitter 104 and the receiver 105, wherein: The control module 101 is used to send out driving control signals; MCU (Microcontroller Unit), sometimes also called Single-Chip Microcomputer, refers to the core part of the machine. Its main functions are: receiving signals and processing them; controlling other components according to programmed instructions; The driving module 102 drives the first transmitter or the second transmitter to transmit an optical signal according to the driving control signal, so that the first transmitter (laser 1) transmits an optical signal to the first object to be measured, or the second transmitter (laser 2) transmits an optical signal to the second object to be measured; The driving module can be a chip or a circuit, as long as it meets certain functions, either a circuit or a combination of chips: ① supply power to the device, ② transmit driving signals, ③ receive signal collection, including signal preprocessing, such as filtering, noise reduction, smoothing, and analog-to-digital conversion; ④ the function of serving as a bridge between the MCU and other devices.

[0018] The lens module 106 is used to receive a first light signal reflected by a first object to be measured, or to receive a second light signal emitted by a second object to be measured; The receiver 105 is configured to receive the first optical signal or the second optical signal.

[0019] The placement of the components follows several principles: There is a receiving device in the center of the two semiconductor lasers. The optical path of the detection conforms to the conventional optical system of off-axis ranging: the optical path between the receiving and transmitting is horizontal.

[0020] The return light signals of the distant objects, i.e. the first and second objects, are considered parallel light because their return light angles are relatively small. The return light signals of the close objects are those with large return light angles, which cannot be received by default. The specific distance varies according to the actual system design.

[0021] like Figure 3 As shown, the detection principle of the embodiment of the present application is based on the radar equation, which sets the distance between the target and the laser radar as R and the divergence angle of the emitted laser beam as θ t , the solid angle is Ω t , the transmittance of the emission optical system is η t , the transmittance of the receiving optical system is η R , the transmittance of the laser pulse in the atmosphere is η a The effective area of ​​the target at the cross section of the laser beam is A. t , the solid angle is Ω r , the cross-sectional area of ​​the laser beam at the target position is A l , the normal direction of the target is O N, the optical axis of the transmitting optical system and the target normal direction O N The angle is θ target , A R is the photosensitive area of ​​the detector, assuming the reflectivity of the target is ρ t , then after diffuse reflection from the target, combined with the transmittance of the receiving system, and passing through the atmosphere again, the laser pulse power received by the receiving system is: ; Optionally, the lens module 106 at least includes a plano-convex lens and a supplementary component, and the supplementary component is attached to the receiving surface of the plano-convex lens.

[0022] Under the premise of hardly affecting the main signal in long-distance testing; the requirement for the size of the supplementary component is that its diameter is one tenth of the diameter of the main structure.

[0023] Optionally, the supplementary component includes at least one of a cemented prism sheet, a small-sized lens, a diffuse reflection patch or a plastic light guide column.

[0024] The light emitted by the laser is collimated, and the divergence angle of the laser is about 1°. The high-power semiconductor laser used in the laser has a peak power greater than 10W. The prism for blind spot filling at close range is completely fitted on the internal receiving surface of the plano-convex lens, and then deflects the light when detecting objects at close range, so that the light that originally deviated from the APD photosensitive surface can be converged on the APD photosensitive surface. Prism sheets can be glued, and small-sized lenses, diffuse reflection patches, plastic light guides, and other solutions are all available, thereby achieving no blind spots near and far.

[0025] The safety grating of the present invention adopts a transmitting and receiving off-axis optical solution and adds a close-range visual field blind spot compensation solution, which can detect long distances and close distances, and realizes detection without blind spots.

[0026] Optionally, the lens module 106 is used to deflect light when detecting an object at a close distance, so that the light originally deviated from the receiver is converged into the receiver.

[0027] Optionally, the first emitter 103 and the second emitter 104 are semiconductor lasers.

[0028] The embodiment of the present invention adopts semiconductor laser for emission, which has a smaller emission angle, concentrated energy and higher peak power; the reception is carried out by a high-sensitivity APD photoelectric detector, and the detection range reaches objects 10m away with no blind spots.

[0029] Optionally, the receiver 105 is an APD photodetector.

[0030] The embodiment of the present invention adopts a minimum optical module assembly solution, which is simple to install and has high reliability. In addition, two emitting lamps only use one APD photodetector, which can greatly reduce the cost.

[0031] Optionally, the control module 101 is a single chip microcomputer or other modules with suitable functions.

[0032] Optionally, the control module 101 is used to send a time-division multiplexed driving control signal.

[0033] A laser transceiver module has two lasers. In order to distinguish between laser 1 and laser 2, the MCU controls the laser driver to achieve time-division multiplexing transmission. Figure 4 As shown, Figure 4 What is displayed are the laser signals emitted by Laser 1 and Laser 2. At the same time, only one laser is turned on, that is, in the first time period, Laser 1 is turned on and sends a laser signal, while Laser 2 is turned off. In the second time period, Laser 1 is turned on and sends a laser signal, while Laser 1 is turned off. It can be seen that Laser 1 and Laser 2 are turned on at different times. In this way, it can be distinguished which transmitter's laser signal the APD receives.

[0034] Optionally, the control module 101 is further configured to: When the distance between the object to be measured and the diffuse reflection safety grating is greater than the preset value, Assuming that the distance between the object to be measured and the diffuse reflection safety grating is L, the distance between the receiver and the transmitter is d, the angle is α, the radius of the plano-convex lens is r, the back focal length of the plano-convex lens is f, and the energy center position of the light spot is s, the following relationship exists: ; ; When s is less than or equal to r, it is determined that the light signal reflected by the measured object is detected.

[0035] Optionally, the control module is further configured to: When s is greater than r, it is determined that the light signal reflected by the detected object is less than a preset value.

[0036] like Figure 2 As shown, it is the smallest laser module of the invention, that is, two lasers, laser 1 and laser 2, share a receiving APD, the position of the APD is in the middle of the two lasers, the two lasers are consistent in space, which can reduce the cost while reducing the volume and cost of the module.

[0037] Since the transmitter and receiver are off-axis systems, when the object is far away, assuming that the distance to the object is L, the distance between the APD and the laser is d, then the angle is α, the chip radius is r, the back focal length of the lens is f, and the energy center position of the light spot is s. Therefore, the following relationship exists: ; ; ; When laser 2 hits a relatively far object 2 to be measured, the angle between the light reflected from the APD and the laser's emitted light is inversely proportional to the distance. The farther the object is, the smaller the sinα angle is, and the more concentrated the light is on the APD, thus enabling long-distance detection. However, when the object is relatively close, the angle between the return light signal and the emitted light becomes larger, and thus it cannot enter the APD reception. This is the off-axis blind area, which is a prism glued to the edge of the lens, so that objects at a close distance can also be detected. When laser 1 detects a relatively close object 1 to be measured, the angle of the return light signal is large, and conventional lenses cannot normally converge the light to the center of the APD position. It can be seen that Figure 2 The "receiving lens module" changes the original refraction angle of the light by attaching a small prism to the edge of the lens, and partially converges it onto the APD photosensitive surface. In this way, the detector can receive the signal again and achieve close-range detection.

[0038] The embodiment of the present application adopts a low-cost, highly integrated dual-transmitter and single-receiver module to form a grating, adopts semiconductor laser emission and APD reception to solve the problem of long-distance detection, and adds a solution for short-distance blind spot fill light, which can accurately detect objects at close range, thereby achieving the safety standard of detection without blind spots. To solve the problem that traditional safety gratings are difficult to install in some scenes and it is very difficult to align the light when installed at a long distance, the diffuse reflection grating of this product can be installed on one side without the need for aligning the light.

[0039] The diffuse reflection safety grating provided by the present invention comprises: a control module, a driving module, a first transmitter, a second transmitter, a receiver, a lens module, a first object to be measured and a second object to be measured, the control module is connected to the driving module, and the driving module is respectively connected to the first transmitter, the second transmitter and the receiver, wherein: the control module is used to send a driving control signal; the driving module is used to drive the first transmitter or the second transmitter to transmit a light signal according to the driving control signal, so that the first transmitter transmits a light signal to the first object to be measured, or the second transmitter transmits a light signal to the second object to be measured; the lens module is used to receive the first light signal reflected by the first object to be measured, or receive the second light signal emitted by the second object to be measured; the receiver is used to receive the first light signal or the second light signal. The dual-transmitting and single-receiving laser module adopts a time-division multiplexing transmission scheme, adopts a semiconductor laser as a light source, and has a corresponding optical design, with a longer shooting distance, and a single-sided diffuse reflection grating, which is easier to install and deploy, and can be used without light alignment and single-sided installation, thereby improving the scope of application of the device.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A diffuse reflection safety grating, characterized in that: The diffuse reflection safety grating includes: a control module, a driving module, a first transmitter, a second transmitter, a receiver, a lens module, a first object to be measured and a second object to be measured, wherein the control module is connected to the driving module, and the driving module is connected to the first transmitter, the second transmitter and the receiver respectively, wherein: The control module is used to send a drive control signal; The driving module is used to drive the first emitter or the second emitter to emit a light signal according to the driving control signal, so that the first emitter emits a light signal to the first object to be measured, or the second emitter emits a light signal to the second object to be measured; The lens module is used to receive a first light signal reflected by the first object to be measured, or to receive a second light signal emitted by the second object to be measured; The receiver is used to receive the first optical signal or the second optical signal.

2. The diffuse reflection safety grating according to claim 1, characterized in that: The lens module at least includes a plano-convex lens and a supplementary component, and the supplementary component is attached to the receiving surface of the plano-convex lens.

3. The diffuse reflection safety grating according to claim 2, characterized in that: The supplementary components include at least one of a cemented prism sheet, a small-sized lens, a diffuse reflection patch or a plastic light guide column.

4. The diffuse reflection safety grating according to claim 2, characterized in that: The lens module is used to deflect light when detecting an object at a close distance, so that the light originally deviated from the receiver is converged into the receiver.

5. The diffuse reflection safety grating according to claim 1, characterized in that: The first emitter and the second emitter are semiconductor lasers.

6. The diffuse reflection safety grating according to claim 1, characterized in that: The receiver is an APD photodetector.

7. The diffuse reflection safety grating according to claim 1, characterized in that: The control module is a single chip microcomputer or a control module capable of realizing the same function.

8. The diffuse reflection safety grating according to claim 1, characterized in that: The control module is used to send out time-division multiplexed drive control signals.

9. The diffuse reflection safety grating according to claim 1, characterized in that: The control module is also used for: When the distance between the object to be measured and the diffuse reflection safety grating is greater than the preset value, Assuming that the distance between the object to be measured and the diffuse reflection safety grating is L, the distance between the receiver and the transmitter is d, the angle is α, the radius of the plano-convex lens is r, the back focal length of the plano-convex lens is f, and the energy center position of the light spot is s, the following relationship exists: ； ； When s is less than or equal to r, it is determined that the light signal reflected by the measured object is detected.

10. The diffuse reflection safety grating according to claim 9, characterized in that: The control module is also used for: When s is greater than r, it is determined that the light signal reflected by the detected object is less than a preset value.

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