Laser displacement sensor capable of measuring mirror target

Abstract

The utility model provides a laser displacement sensor capable of measuring a mirror reflection target. The laser device enters the mirror target surface at a certain inclination angle, the linear array CMOS device and the laser device are symmetrically arranged with the normal of the mirror target surface as the symmetry axis, the attenuation product is adopted to greatly weaken the laser intensity, the simple ARM is adopted as a processor, and only simple operation is needed. The laser, the attenuation piece, the focusing mirror, the reflecting mirror and the CMOS are fixed at the same time through the integrated connecting plate, the performance is stable and reliable, assembling is convenient and fast, and the production efficiency is improved. According to the sensor, the displacement and distance measurement of a precise reflection target can be realized, the measurement precision is high, the integrated measuring head is good in integration degree, the cost is low, the cost performance is high, and the sensor has wide practicability and universality.

Description

TECHNICAL FIELD

[0001] The utility model relates to a laser displacement sensor. Specifically, it is a laser displacement sensor capable of measuring a mirror surface reflection target. BACKGROUND

[0002] The laser displacement sensor is a sensor for measuring the distance of a target based on the laser triangulation principle. It has the advantages of non-contact, high precision, high speed, and wide applicability, and is increasingly widely used.

[0003] However, the existing laser displacement sensor cannot measure the distance and displacement of a mirror surface reflection target. 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, thereby realizing displacement and distance measurement. However, for a target with a mirror surface (such as a wafer, stainless steel, or a surface-coated workpiece), 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, thus failing to measure.

[0004] Currently, some brands in the industry use a makeshift solution, i.e., directly rotating the existing laser displacement sensor by half the working angle to realize the measurement of a mirror surface target. Although this method can realize the measurement of a mirror surface target, the precision cannot be guaranteed. The reasons are as follows:

[0005] First, the receiving light path of the original laser displacement sensor is designed according to the imaging principle of the diffuse reflection target spot, while the mirror target produces reflected laser direct radiation, and the two light flows are completely different. Using one light path for another situation forcibly will greatly reduce the effect.

[0006] Second, the method of rotating the probe head by half the working angle lacks strict and accurate positioning, and the measurement precision cannot be guaranteed, and the operation is very inconvenient.

[0007] Third, after the laser is reflected by the mirror surface target, the direct radiation of the laser to the imaging surface of the photoelectric device may cause damage to the photoelectric device.

[0008] Fourth, the direct radiation of the laser to the photoelectric device causes the imaging waveform to change, and the diffuse reflection algorithm is no longer applicable, and needs to be redesigned and evaluated. INVENTION CONTENTS

[0009] The utility model discloses to the current situation that the laser displacement sensor cannot measure mirror surface reflection target, propose a kind of laser displacement sensor of measurable mirror surface reflection target.The sensor adopts laser to be incident mirror surface target surface with certain inclination angle, adopts linear array CMOS as photoelectric device, with laser to be symmetrical with mirror surface target surface normal axis arrangement, receive reflected laser signal;Adopt attenuating piece to greatly weaken laser intensity, protect photoelectric device from receiving damage;Adopt focusing mirror to converge reflected laser, meet the imaging length demand of CMOS;Adopt mirror to fold back optical path, reduce probe volume;Adopt simple ARM as processor, only need simple operation, eliminate the complex calculation of waveform positioning;Adopt integrated connecting plate to fix laser, attenuating piece, focusing mirror, mirror, CMOS, not only stable and reliable performance, and easy and fast assembly, improve production efficiency.The sensor can realize the displacement and distance measurement of precision reflection target, measurement precision is high, integrated probe integration is good, cost is low, high performance price ratio, have extensive practicality and universality.

[0010] The utility model is realized through the following technical schemes:

[0011] The utility model discloses a kind of laser displacement sensors of measurable mirror surface reflection target, and the speciality thereof is that the sensor includes laser, focusing mirror, window piece, attenuating piece, imaging mirror, CMOS device, connecting plate, processing circuit, shell several parts, wherein:

[0012] The laser is semiconductor laser diode, when measured target is in range, under the control of processing circuit, open laser, generate measurement laser beam and keep constant, complete measurement function;When measured target exceeds measurement range, under the control of processing circuit, intermittently open and close laser, realize automatic safety protection function to human eye, and can prolong the service life of laser;

[0013] The focusing mirror is collimating focusing mirror, can be made of optical glass or resin material, the divergent light beam of laser diode is converged into collimating focusing light beam, and is projected to the surface of measured mirror surface target with certain inclination angle;

[0014] The window piece is optical window piece, ensure that laser beam can pass through with low loss, simultaneously play sealing protection function;

[0015] The attenuating piece is full-waveband medium attenuating piece, can greatly attenuate the intensity of reflected laser from mirror surface target surface, reduce the risk that CMOS device occurs damage, simultaneously can filter the influence of ambient light;

[0016] The imaging mirror is aspheric imaging mirror, the reflected laser from mirror surface target surface is imaged, and is projected to CMOS device, to guarantee measurement precision;

[0017] The CMOS device is a linear array CMOS device, can accept reflected laser irradiation from a mirror target surface, and outputs an electrical signal related to a light beam irradiation centroid position, which is sent to a processing circuit for processing;

[0018] The connecting plate is an integrated multifunctional structural member, can accurately and reliably position and fix the laser, the focusing mirror, the imaging mirror and the CMOS device, forms a photoelectric assembly, facilitates separate assembly and debugging, improves production efficiency and reduces production cost;

[0019] The processing circuit is a measurement and control circuit with ARM as the core, on the one hand, can control the laser to emit laser or turn off the laser as needed, on the other hand, receives the electrical signal from the CMOS device and calculates the displacement value;

[0020] The shell is a high-stability integrated structural member, can accurately position and reliably fix the connecting plate, and can also position and fix the entire sensor; the place where the shell fixes the attenuation piece is an embedded inclined structure, on the one hand, makes the normal direction of the filter close to the optical axis of the imaging mirror, improves the imaging quality, and on the other hand, can form a light cylinder by the shell and play a certain light shielding role.

[0021] The working process of the laser displacement sensor capable of measuring a mirror reflection target is as follows: the laser beam emitted by the laser passes through the focusing mirror and is focused, is projected to the surface of the measured mirror target at a certain inclination angle, the reflected laser beam is greatly reduced in intensity after passing through the attenuation piece, and is imaged to the sensitive surface of the CMOS device by the imaging mirror. The CMOS device outputs an electrical signal related to the image spot and sends it to the processing circuit. The processing circuit finally obtains the distance value between the sensor and the measured mirror target through data processing.

[0022] The laser displacement sensor capable of measuring a mirror reflection target is special in that the included angle (i.e. the incidence angle) between the laser beam and the normal of the surface of the measured mirror target can be changed according to the distance of the measured mirror target and the displacement range, so that the shell is of a unified specification and can adapt to all different specifications, thereby ensuring good interchangeability of the entire series of sensors and meeting the mass production process requirements, thereby significantly reducing the cost.

[0023] The laser displacement sensor capable of measuring a mirror reflection target is special in that the attenuation piece has a high attenuation rate, can not only avoid damaging the CMOS device, but also ensure that the imaged waveform has a good amplitude height and ensure the measurement accuracy. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1It is the composition schematic view of the laser displacement sensor capable of measuring mirror surface reflection target of the utility model.

[0025] Figure 2 It is the incident angle selection principle schematic view of different range of the sensor of the utility model.

[0026] Figure 3 It is the attenuation piece principle schematic view of the sensor of the utility model.

[0027] In the figure, 1-laser, 2-focusing mirror, 3-window piece, 4-filter, 5-imaging mirror, 6-CMOS device, 7-connection plate, 8-processing circuit, 9-housing, 10-measured mirror surface target. Specific implementation

[0028] The embodiment of the utility model is described in detail below in combination with the drawings, and the embodiment is implemented on the premise of the technical scheme of the utility model, gives detailed implementation mode and specific operation process, but the protection scope of the utility model is not limited to the following embodiment.

[0029] The speciality of the laser displacement sensor capable of measuring mirror surface reflection target of the utility model lies in, the sensor includes laser 1, focusing mirror 2, window piece 3, attenuation piece 4, imaging mirror 5, CMOS device 6, connection plate 7, processing circuit 8, housing 9 several parts, as shown in Figure 1 , wherein:

[0030] The laser 1 is semiconductor laser diode, when the measured mirror surface target 10 is in the range of range, under the control of processing circuit 8, open laser 1, produce measuring laser beam and keep constant, complete measurement function, when the measured mirror surface target 10 exceeds the measurement range, under the control of processing circuit 8, intermittently open and close laser 1, realize the automatic safety protection function to human eye, and can prolong the service life of laser 1;

[0031] The focusing mirror 2 is collimating focusing mirror, can be made of optical glass or resin material, converges the divergent light beam of laser diode 1 into collimating focusing light beam, and is projected to the surface of measured mirror surface target 10 with a certain inclination angle (for example Figure 1 The θ of one kind);

[0032] The window piece 3 is optical window piece, ensures that the laser beam can pass through with low loss, and the transmittance is not less than 90%, and simultaneously plays the sealing protection function;

[0033] The attenuation piece 4 is full-waveband medium attenuation piece, can greatly attenuate the intensity of reflected laser from the surface of mirror surface target, and the attenuation rate is not less than 5%, reduces the risk of damage of CMOS device 6, and simultaneously can filter out the influence of ambient light;

[0034] The imaging mirror 5 is a non-spherical imaging mirror, which images the reflected laser from the surface of the mirror surface reflection target 10 and projects to the CMOS device 6 to ensure the measurement accuracy.

[0035] The CMOS device 6 is a linear array CMOS device, which can receive the reflected laser from the surface of the mirror surface target 10 and output an electrical signal related to the light beam irradiation centroid position, and send the electrical signal to the processing circuit 8 for processing.

[0036] The connecting plate 7 is an integrated multifunctional structural member, which can accurately and reliably position and fix the laser 1, the focusing mirror 2, the imaging mirror 5 and the CMOS device 6 to form an optoelectronic assembly, facilitate separate assembly and debugging, improve production efficiency and reduce production cost.

[0037] The processing circuit 8 is a measurement and control circuit with ARM as the core, which can control the laser 1 to emit laser or turn off the laser as needed, and receive the electrical signal from the CMOS device 6 to calculate the displacement value.

[0038] The housing 9 is a high-stability integrated structural member, which can accurately position and reliably fix the connecting plate 7 and realize the positioning and fixing of the entire sensor. The place where the housing 9 fixes the attenuation piece 4 is an embedded inclined structure, which makes the normal direction of the attenuation piece consistent with the optical axis of the imaging mirror to improve the imaging quality, and can form a light cylinder by the housing 9 to play a certain light shielding role.

[0039] The working process of the laser displacement sensor capable of measuring the mirror surface reflection target is as follows: the laser beam emitted by the laser 1 is focused by the focusing mirror 2 and projected to the surface of the measured mirror surface target 10 at a certain inclination angle, the reflected laser beam is greatly reduced in intensity after passing through the attenuation piece 4, and is imaged to the sensitive surface of the CMOS device 6 by the imaging mirror 5. The CMOS device 6 outputs an electrical signal related to the image spot and sends it to the processing circuit 8. The processing circuit 8 finally obtains the distance value between the sensor and the measured mirror surface target 10 through data processing.

[0040] The laser displacement sensor capable of measuring the mirror surface reflection target is also special in that the included angle (i.e. the incidence angle) between the laser beam 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, as shown in the figure. Figure 2 Thus, the housing has a unified specification and can adapt to all different specifications, so that the full series of sensors have good interchangeability and meet the mass production process requirements, thereby significantly reducing the cost.

[0041] The special laser displacement sensor for measuring mirror surface reflection target of the utility model further has the following advantages: the attenuation sheet 4 has high attenuation rate, which can not only avoid damaging the CMOS device 6, but also ensure that the imaging waveform has good amplitude height and measurement accuracy. Figure 3

[0042] Compared with the prior art, the low-cost laser displacement sensor has the following advantages:

[0043] (1) The laser displacement sensor for measuring mirror surface reflection target of the utility model adopts laser oblique incidence 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.

[0044] (2) The laser displacement sensor for measuring mirror surface reflection target of the utility model adopts a high-proportion attenuation sheet to greatly reduce the intensity of reflected laser, ensure the safety of the CMOS device, optimize the imaging waveform, and improve the measurement and control accuracy.

[0045] (3) The laser displacement sensor for measuring mirror surface reflection target 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.

[0046] Therefore, the technical scheme of the utility model has very outstanding technical advantages and progress compared with the traditional laser displacement sensor.​

Claims

1. A laser displacement sensor capable of measuring a specular mirror target, characterized by, The sensor comprises a laser, a focusing mirror, a window sheet, an attenuation sheet, an imaging mirror, a CMOS device, a connecting plate, a processing circuit, and a housing. The laser is a semiconductor laser diode. The focusing mirror is a collimating focusing mirror made of optical glass, which converges the divergent light beam of the laser diode into a collimating focusing light beam and projects it to the surface of the measured mirror target at a certain inclination angle. The window sheet is an optical window sheet, which ensures that the laser beam can pass through with low loss and also plays a sealing protection role. The attenuation sheet is a full-waveband medium attenuation sheet. The imaging mirror is an aspheric imaging mirror, which images the reflected laser from the surface of the mirror target and projects it to the CMOS device to ensure measurement accuracy. The CMOS device is a linear array CMOS device, which can receive the reflected laser from the surface of the mirror target and output an electrical signal related to the position of the light beam irradiation center to the processing circuit for processing. The connecting plate is an integrated multifunctional structural member, which can accurately and reliably position and fix the laser, the focusing mirror, the imaging mirror, and the CMOS device to form an optoelectronic assembly, facilitating separate assembly and debugging, improving production efficiency, and reducing production cost. The processing circuit is a measurement and control circuit with ARM as the core, which can control the laser to emit laser or turn it off as needed, and receive the electrical signal from the CMOS device to calculate the displacement value. The housing is a high-stability integral structural member, which can accurately position and reliably fix the connecting plate and also realize the positioning and fixing of the entire sensor. The housing is embedded with an inclined structure at the position where the attenuation sheet is fixed, which makes the normal direction of the filter close to the optical axis of the imaging mirror to improve imaging quality and also forms a light cylinder to play a certain light shielding role.

2. The laser displacement sensor capable of measuring a mirror target according to claim 1, wherein the angle between the laser beam and the normal of the surface of the measured mirror target can be changed according to the distance of the measured mirror target and the displacement range, so that the housing has a unified specification.

3. The laser displacement sensor capable of measuring a mirror target according to claim 1, wherein the attenuation sheet has a high attenuation rate. ​ ​

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