Mirror surface target displacement sensor capable of inhibiting inclination influence

Abstract

The utility model provides a mirror surface target displacement sensor capable of inhibiting inclination influence. A left laser and a right laser which are symmetrically arranged are adopted and are incident to a mirror surface target surface at the same inclination angle; a left receiving light path and a right receiving light path which are symmetrically arranged and a linear array CMOS device are adopted to receive reflected laser signals, and an attenuation piece is adopted for each path of receiving to greatly weaken the laser intensity, so that photoelectric devices are protected from being damaged. When the mirror surface target moves back and forth, the distance between the imaging waveforms generated on the left CMOS device and the right CMOS device also changes and belongs to a linear positive correlation relation, and therefore the distance value of the two imaging waveforms can be used for representing the distance of the measured target. When a measuring head or a measured mirror target is inclined, imaging waveforms on the left CMOS device and the right CMOS device are shifted in the same direction, the offset amount is the same, and therefore the distance value between the imaging waveforms on the two CMOS devices does not change, and the influence of inclination can be completely overcome.

Description

TECHNICAL FIELD

[0001] The utility model relates to a displacement sensor. Specifically, it is a mirror target displacement sensor capable of inhibiting the influence of inclination. BACKGROUND

[0002] The laser displacement sensor is a sensor for measuring the distance of a target based on the laser triangulation principle, and has the advantages of non-contact, high precision, high speed and wide application, and is applied more and more widely. However, the existing laser displacement sensor mainly measures diffuse reflection targets and cannot measure the distance and displacement of mirror reflection targets. The reason is that the laser beam emitted by the traditional laser displacement sensor is irradiated on the surface of a diffuse reflection target and forms a laser spot. The spot is imaged onto the surface of a photoelectric device through an imaging mirror on one side, so as to realize displacement and distance measurement. However, for a target with a mirror reflection surface (such as a wafer, stainless steel, a surface-coated workpiece, etc.), the laser beam vertically incident will be directly reflected to the laser, and the photoelectric device on one side cannot observe the laser spot at all, so the measurement fails.

[0003] The current solution widely used in the industry is to rotate the existing diffuse reflection laser displacement sensor by half the working angle, so that the reflected light directly enters the receiving end, thereby realizing the measurement of the mirror surface target. Although this method can realize the measurement of the mirror surface target, the precision cannot be guaranteed. The reasons are as follows:

[0004] Firstly, the receiving light path of the laser displacement sensor for measuring diffuse reflection targets belongs to the imaging light path, while the mirror target produces reflected laser direct reflection, and the two light paths are completely different. Using one light path for another situation forcibly will inevitably result in a big discount.

[0005] Secondly, the method of rotating the measuring head by half the working angle lacks strict and accurate positioning, and the measurement precision cannot be guaranteed, and the operation is very inconvenient.

[0006] Thirdly, after the laser is reflected by the mirror target surface, the direct reflection of the photoelectric device imaging surface may cause damage to the photoelectric device.

[0007] Fourthly, when the sensor measuring head or the measured target is tilted during installation, the position of the reflected light will be directly changed, thereby causing serious measurement errors. The inclination error is the largest item among all error items and is the most important factor affecting the measurement precision of the mirror target. INVENTION CONTENTS

[0008] The utility model discloses to the current laser displacement sensor cannot overcome the present situation that the probe or mirror surface target inclination has serious influence on the measuring accuracy, and proposes a mirror surface target displacement sensor that can inhibit the influence of inclination. The sensor adopts two symmetrical laser devices, and the symmetry axis is parallel to the normal line of the measured mirror surface target, and the same inclination angle is incident to the surface of the mirror surface target. The receiving light path and the linear array CMOS device are used as the photoelectric device to receive the reflected laser signal, and the symmetry axis is parallel to the normal line of the measured mirror surface target. The receiving light path and the laser beam are also axially symmetrical, and the symmetry axis is parallel to the normal line of the measured mirror surface target. Each laser device corresponds to a receiving light path and a CCD. Each receiving light path uses an attenuation sheet to greatly weaken the laser intensity, and the photoelectric device is protected from damage. Each receiving light path uses an imaging mirror to converge the reflected laser, so as to meet the imaging length requirement of the CMOS device. When the mirror surface target moves forward and backward, the distance between the imaging waveforms generated on the left and right CMOS devices also changes, and it is a linear positive correlation. Therefore, the distance value of the two imaging waveforms can be used to represent the distance of the measured target. When the probe or the measured mirror surface target is inclined, the imaging waveforms on the left and right CMOS devices will be offset in the same direction, and the offset amount is the same. Therefore, the distance value between the imaging waveforms on the two CMOS devices does not change, and the influence of inclination can be completely overcome.

[0009] The utility model is realized through the following technical schemes:

[0010] The mirror surface target displacement sensor that can inhibit the influence of inclination is characterized in that the sensor comprises a laser device, a focusing mirror, a window sheet, an attenuation sheet, an imaging mirror, a CMOS device, a synchronizer, a processing circuit and a shell.

[0011] The laser device is a semiconductor laser diode, and there are two of them, located on the left and right sides of the sensor probe. They can be turned on or off under the control of the processing circuit to realize measurement and eye protection functions.

[0012] The focusing mirror is an optical collimating focusing mirror, and there are two of them, located on the left and right sides of the sensor probe and the front ends of the left and right laser devices. They are made of optical glass or resin material, and converge the divergent light beams of the left and right laser devices into two collimating focusing light beams, which are incident to the surface of the measured mirror surface target at the same inclination angle.

[0013] The window sheet is an optical window sheet, and there are two of them, located on the left and right sides of the front end of the shell and the front end of the focusing mirror. They ensure that the left and right laser beams can pass through with low loss, and also play a sealing protection role.

[0014] The attenuation pieces are neutral attenuation pieces, and there are two, which are respectively located in the middle area of the front end of the shell, and respectively receive the reflected laser beams generated by the left and right laser beams on the surface of the measured target, can greatly attenuate the intensity of the reflected laser from the mirror surface target, reduce the risk of damage to the CMOS device, and can greatly suppress the influence of ambient light;

[0015] The imaging mirrors are aspherical imaging mirrors, and there are two, which are respectively located inside the sensor probe, and the rear ends of the left and right attenuation pieces, converge the reflected laser from the mirror surface target, and respectively project to the left and right CMOS devices to realize the measurement of the target distance;

[0016] The CMOS devices are linear array CMOS devices, and there are two, which are respectively located at the rear ends of the left and right imaging mirrors, for respectively receiving two reflected laser beams from the mirror surface target, and respectively outputting an electrical signal related to the light beam irradiation centroid position, and sending into a processing circuit for subsequent processing;

[0017] The synchronizer is a pure logic circuit, which synchronously triggers the left and right CMOS devices under the control of the processing circuit, and starts to work, so as to ensure the real-time and synchronization of the imaging waveforms obtained by the left and right CMOS devices;

[0018] The processing circuit is a measurement and control circuit with ARM as the core, which on the one hand controls the left and right lasers to emit laser or close laser according to the need, and on the other hand directly synchronously triggers the left and right CMOS devices through the synchronizer, and receives the electrical signals from the left and right CMOS devices, and finally obtains the displacement value through data processing and calculation;

[0019] The shell is a high-stability integral structure, which can accurately position and reliably fix the internal components, and can also realize the positioning and fixing of the whole sensor probe; the place where the shell fixes the attenuation piece is an embedded inclined structure, which on the one hand makes the normal direction of the attenuation piece close to the optical axis of the imaging mirror, improves the imaging quality, and on the other hand can form a light shielding cylinder with the shell, and plays a certain light shielding role.

[0020] The working process of the mirror surface target displacement sensor capable of inhibiting the inclination influence is as follows: under the control of the processing circuit, two laser beams are simultaneously emitted by the left and right two lasers, are focused by the left and right two focusing mirrors, and are projected to the surface of the measured mirror surface target at the same inclination angle. The two reflected laser beams are reduced in intensity by two attenuation pieces, and are converged to the sensitive surfaces of the left and right two CMOS devices by the left and right two imaging mirrors. The processing circuit sends a synchronous control signal to the synchronizer, synchronously triggers the left and right two CMOS devices to work, and respectively outputs the electrical signals related to the imaging light spot centroids and sends the electrical signals into the processing circuit. The processing circuit finally obtains the distance value between the sensor and the measured mirror surface target through data processing.

[0021] The mirror surface target displacement sensor capable of inhibiting the inclination influence is characterized in that the included angle (i.e. the incidence angle) between the left and right two laser beams and the normal of the surface of the measured mirror surface target can be changed according to the distance and displacement range of the measured mirror surface target, so that the shell is of a unified specification and can adapt to all different specifications, thereby ensuring the good interchangeability of the full series of sensors and meeting the mass production work process requirements, so as to significantly reduce the cost.

[0022] The mirror surface target displacement sensor capable of inhibiting the inclination influence is characterized in that the left and right two laser beams are inwardly incident to the surface of the measured mirror surface target, and the distance between the two incident points should be greater than 2 times the diameter of the imaging mirror.

[0023] The mirror surface target displacement sensor capable of inhibiting the inclination influence is characterized in that the attenuation piece 4 has a high attenuation rate, which can not only avoid damaging the CMOS device 6, but also ensure that the imaging waveform has a good amplitude height and ensures the measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 is the composition schematic view of the mirror surface target displacement sensor capable of inhibiting the inclination influence of the utility model.

[0025] Figure 2 is the working principle schematic view of the mirror surface target displacement sensor capable of inhibiting the inclination influence of the utility model.

[0026] Figure 3 is the inclination inhibition optical path principle schematic view of the sensor of the utility model.

[0027] In the figure, 1 is a laser, 2 is a focusing mirror, 3 is a window piece, 4 is an attenuation piece, 5 is an imaging mirror, 6 is a CMOS device, 7 is a synchronizer, 8 is a processing circuit, 9 is a shell, 10 is a measured mirror surface target. DETAILED DESCRIPTION

[0028] The embodiments of the utility model will be described in detail below with reference to the drawings, and the embodiments are implemented on the premise of the technical scheme of the utility model, and detailed implementation modes and specific operation processes are given, but the protection scope of the utility model is not limited to the following embodiments.

[0029] The speciality of the mirror target displacement sensor capable of restraining the influence of inclination provided by the utility model lies in that the sensor comprises a laser 1, a focusing mirror 2, a window sheet 3, an attenuation sheet 4, an imaging mirror 5, a CMOS device 6, a synchronizer 7, a processing circuit 8 and a shell 9, as shown in the figure, wherein: Figure 1

[0030] The laser 1 is a semiconductor laser diode, and there are two, which are 1a and 1b respectively, and are located at the left and right sides inside the sensor probe head, can be opened or closed under the control of the processing circuit 8, and realize the measurement and eye protection functions;

[0031] The focusing mirror 2 is an optical collimating focusing mirror, and there are two, which are 2a and 2b respectively, and are located at the left and right sides inside the sensor probe head and the front ends of the left and right two lasers 1a and 1b, are made of optical glass or resin material, respectively converge the divergent light beams of the left and right two lasers 1a and 1b into two collimating focusing light beams, and are projected to the surface of the measured mirror target 10 at the same inclination angle;

[0032] The window sheet 3 is an optical window sheet, and there are two, which are 3a and 3b respectively, and are located at the left and right sides of the front end of the shell 9 and the front ends of the focusing mirrors 2a and 2b, ensure that the left and right two laser beams can pass through with low loss, and also play a sealing protection role;

[0033] The attenuation sheet 4 is a neutral attenuation sheet, and there are two, which are 4a and 4b respectively, and are located at the middle region of the front end of the shell 9, respectively receive the reflected laser beams of the left and right two laser beams on the surface of the measured target 10, can greatly attenuate the intensity of the reflected laser beams from the surface of the mirror target 10, reduce the risk of damage of the CMOS device 6, and also can greatly restrain the influence of ambient light;

[0034] The imaging mirror 5 is an aspheric imaging mirror, and there are two, which are 5a and 5b respectively, and are located inside the sensor probe head and the rear ends of the left and right two attenuation sheets, converge the reflected laser beams from the surface of the mirror target, and are respectively projected to the left and right two CMOS devices to realize the measurement of the target distance;

[0035] ​The CMOS device 6 is a linear array CMOS device, and there are two, 6a and 6b respectively, which are located at the rear ends of the left and right imaging mirrors 5a and 5b respectively, and are used for receiving two reflected laser beams from the surface of the mirror target 10 respectively, and outputting electric signals related to the positions of the beam irradiation centers respectively, and sending into the processing circuit 8 for subsequent processing.

[0036] The synchronizer 7 is a pure logic circuit, which synchronously triggers the left and right CMOS devices 6a and 6b under the control of the processing circuit 8, and starts the work, so as to ensure the real-time and synchronization of the imaging waveforms obtained by the left and right CMOS devices 6a and 6b.

[0037] The processing circuit 8 is a measurement and control circuit with ARM as the core, which controls the left and right lasers 1a and 1b on one hand, and emits laser or closes the laser according to the needs, and directly synchronously triggers the left and right CMOS devices 6a and 6b through the synchronizer 7 on the other hand, and receives the electric signals from the left and right CMOS devices 6a and 6b, and finally obtains the displacement value through data processing and calculation.

[0038] The shell 9 is a high-stability integral structure, which can accurately position and reliably fix the internal components, and can also position and fix the whole sensor measuring head; the positions where the shell fixes the attenuation pieces 4a and 4b are embedded inclined structures, which can make the normal directions of the attenuation pieces 4a and 4b close to the optical axes of the imaging mirrors and improve the imaging quality, and can also form light shielding tubes by the shell and play a certain light shielding role.

[0039] The working process of the mirror target displacement sensor capable of inhibiting the influence of inclination of the utility model is as follows: Figure 2 and Figure 3 As shown in the figures, two laser beams are emitted by the left and right lasers 1a and 1b simultaneously under the control of the processing circuit 8, and are focused by the left and right focusing mirrors 2a and 2b and the window pieces 3a and 3b respectively, and are projected to the surface of the measured mirror target 10 at the same inclination angle. The two reflected laser beams are greatly reduced in intensity after passing through the two attenuation pieces 4a and 4b respectively, and are converged to the sensitive surfaces of the left and right CMOS devices 6a and 6b by the left and right imaging mirrors 5a and 5b respectively. The processing circuit 8 sends a synchronous control signal to the synchronizer 7, and synchronously triggers the left and right CMOS devices 6a and 6b to work, and outputs the electric signals related to the imaging light spot centers respectively, and sends into the processing circuit 8. The processing circuit 8 finally obtains the distance value between the sensor and the measured mirror target 10 through data processing.

[0040] The speciality of the mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model lies in that the included angle (i.e. the incidence angle) between the left and right two laser beams and the normal line of the surface of the measured mirror surface target 10 can be changed according to the distance and displacement range of the measured mirror surface target 10, so that the shell 9 is of a unified specification and can adapt to all different specifications, thereby ensuring good interchangeability of the full series of sensors and simultaneously meeting the mass production work process requirements, so as to significantly reduce the cost.

[0041] The speciality of the mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model lies in that the left and right two laser beams are inwardly incident on the surface of the measured mirror surface target 10, and the distance between the two incidence points should be greater than 2 times the diameter of the imaging mirror 5.

[0042] The speciality of the mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model lies in that the attenuation sheet is of high attenuation rate, generally not less than 80%, which can not only avoid damage to the CMOS device, but also ensure that the imaging waveform has good amplitude height and ensures the measurement accuracy.

[0043] Compared with the prior art, the mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model has the beneficial effects that:

[0044] (1) The mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model adopts a laser inclination incidence mode and a focused light path to realize distance measurement of the mirror surface target, so that the material cost of the sensor is the same as that of the traditional laser displacement sensor, and the cost performance advantage is outstanding.

[0045] (2) The mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model adopts two mechanisms and expensive receiving light paths, which are arranged in axial symmetry and form a differential structure, so that the measurement error caused by the inclination of the measuring head or the measured target can be completely eliminated, and the user experience and practicality are greatly improved.

[0046] (3) The mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model adopts a high-proportion attenuation sheet, which greatly reduces the intensity of the reflected laser light, ensures the safety of the CMOS device, optimizes the imaging waveform and improves the measurement and control accuracy.

[0047] (4) The mirror surface target displacement sensor capable of inhibiting the influence of inclination of the utility model can select different incidence angles according to the distance of the target, so as to ensure the same span, so that the size of the shell remains the same, the production cost is reduced, and the cost performance is maintained.

[0048] It can be seen that the technical scheme of the utility model has very outstanding technical advantages and progress compared with the traditional laser displacement sensor.

Claims

1. A mirror target displacement sensor capable of suppressing tilt effects, characterized in that, The sensor comprises a laser, a focusing mirror, a window sheet, an attenuation sheet, an imaging mirror, a CMOS device, a synchronizer, a processing circuit, and a shell, wherein: The laser is a semiconductor laser diode, and there are two lasers located on the left and right sides inside the sensor head, which can be turned on or off under the control of the processing circuit to realize measurement and eye protection functions. The focusing mirror is an optical collimating focusing mirror, and there are two focusing mirrors located on the left and right sides inside the sensor head and in front of the two lasers, which are made of optical glass or resin material, and converge the divergent light beams of the two lasers into two collimating focusing beams with the same inclination angle and project them onto the surface of the measured mirror target. The window sheet is an optical window sheet, and there are two window sheets located on the left and right sides of the front end of the shell and in front of the focusing mirrors, which ensure that the two laser beams can pass through with low loss and also play a sealing protection role. The attenuation sheet is a neutral attenuation sheet, and there are two attenuation sheets located in the middle region of the front end of the shell, which receive the reflected laser beams from the surface of the measured target. The imaging mirror is an aspheric imaging mirror, and there are two imaging mirrors located inside the sensor head and behind the two attenuation sheets, which converge the reflected laser beams from the surface of the mirror target and project them onto the two CMOS devices to realize the measurement of the target distance. The CMOS device is a linear array CMOS device, and there are two CMOS devices located behind the two imaging mirrors, which receive the two reflected laser beams from the surface of the mirror target and output electrical signals related to the light beam irradiation centroid position to the processing circuit for subsequent processing. The synchronizer is a pure logic circuit that synchronously triggers the two CMOS devices under the control of the processing circuit to start work, so as to ensure the real-time and synchronization of the imaging waveforms obtained by the two CMOS devices. The processing circuit is a measurement and control circuit with ARM as the core, which controls the two lasers to emit laser beams or turn off the laser beams as needed, synchronously triggers the two CMOS devices through the synchronizer, receives the electrical signals from the two CMOS devices, and finally obtains the displacement value through data processing and calculation. The shell is a high-stability integral structure that can accurately position and reliably fix the internal components and also realize the positioning and fixing of the entire sensor head. The part where the shell fixes the attenuation sheet is an embedded inclined structure, which makes the normal direction of the attenuation sheet close to the optical axis of the imaging mirror to improve the imaging quality, and also forms a light shield cylinder to play a certain light shielding role.

2. The mirror target displacement sensor according to claim 1, further characterized by: The angle between the laser beam and the normal of the surface of the measured mirror target can be changed according to the distance and displacement range of the measured mirror target, so that the shell has a unified specification and can adapt to all different specifications.

3. The mirror target displacement sensor according to claim 1, further characterized by: The two laser beams are incident inward to the surface of the measured mirror target, and the distance between the two incident points should be greater than 2 times the diameter of the imaging mirror.

4. The mirror target displacement sensor according to claim 1, further characterized by: The attenuation sheet has a high attenuation rate.

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