Light intensity compensation type displacement sensor

Abstract

The utility model relates to a light intensity compensation type displacement sensor, which comprises a laser used for emitting laser beams and an optical splitter arranged between the laser and a right-angle mirror group, the right-angle mirror group is arranged on a measured object, and the optical splitter is used for receiving incident laser beams and dividing the laser beams into first laser beams and second laser beams according to a proportion. The first laser beam sends moire fringes generated by the first laser beam to the first photoelectric detector through the right-angle mirror group and the grating pair to measure the light intensity, the second photoelectric detector receives and measures the light intensity of the second laser beam, and the processor compensates the first photoelectric detector according to the ratio of transmission to reflection of the optical splitter. According to the utility model, the optical splitter is arranged, so that the measurement intensity of the second laser beam split by the optical splitter in proportion is used as the constant light intensity by the second photoelectric detector, and the light intensity error measured by the first photoelectric detector is corrected by performing illumination compensation on the first laser beam processed by the grating pair through the processor.

Description

Technical Field

[0001] This utility model relates to the field of grating sensor technology, specifically to a light intensity compensated displacement sensor. Background Technology

[0002] The novel principle of displacement measurement based on optical triangulation amplification combines triangular wave optics with a high-precision PSD (Position Sensitive Device) to achieve this. Through optical triangulation amplification, a small horizontal displacement t is magnified to T on the photodetector (PSD), significantly improving the accuracy of length measurement. Optical sensors have thus become widely used tools in the field of measurement technology. However, the accuracy of these sensors is closely related to the accuracy of the PSD, and further improvements in PSD accuracy remain challenging.

[0003] Moiré fringes are characterized by their extreme sensitivity to the displacement of gratings. When the grating moves relative to the grating, the moiré fringes also move accordingly. This phenomenon is widely used in precision measurement techniques, such as grating ruler displacement sensors. By calculating the changes in the moiré fringes, the displacement and velocity of an object can be accurately measured.

[0004] In actual measurements, the more grating lines there are, the more moiré fringe signals are generated when moving the same distance, resulting in more accurate calculations. However, this also has drawbacks, such as extremely fine grating lines leading to minimal changes in light intensity and making the moiré fringe signals difficult to distinguish. Furthermore, the light intensity of the light source will also vary periodically within a certain small range, such as... Figure 1 As shown, this makes it difficult to resolve moiré fringes. Utility Model Content

[0005] The purpose of this invention is to solve the technical problem of difficulty in signal resolution of moiré fringes caused by changes in light source intensity, which leads to measurement errors. It provides a novel displacement sensor measurement system that can compare the intensity of the original laser beam emitted by a laser using a beam splitter, and compensate the light to the photodetector according to the beam splitter's splitting ratio. The main concept is as follows:

[0006] A light intensity compensated displacement sensor includes a laser, a right-angle mirror group, a beam splitter, a grating pair, a photoelectric detection component, and a processor. The beam splitter is disposed between the laser and the right-angle mirror group, and the right-angle mirror group is disposed on the object being measured.

[0007] A laser used to emit an incident laser beam;

[0008] A beam splitter is used to receive an incident laser beam and split the incident laser beam into a first laser beam and a second laser beam in proportion.

[0009] A right-angle mirror assembly is used to receive the first laser beam and reflect it twice before emitting it.

[0010] A grating pair is used to generate moiré fringes for the first laser beam;

[0011] The photoelectric detection assembly includes a first photodetector and a second photodetector. The first photodetector is used to receive and measure the light intensity of a first laser beam emitted from the grating sub, and the second photodetector is used to receive and measure the light intensity of a second laser beam.

[0012] The processor is used to calculate the light intensity change rate of the second photodetector and the first photodetector, compensate the first photodetector according to the transmission-to-reflection ratio of the beam splitter, and calculate the displacement of the compensated moiré fringes.

[0013] This scheme sets up a beam splitter so that the second photodetector uses the measured intensity of the second laser beam split by the beam splitter as a constant light intensity. Then, the processor performs illumination compensation on the first laser beam after processing the grating pair, so that the light intensity error measured by the first photodetector is corrected.

[0014] Preferably, the right-angle mirror group includes multiple right-angle mirrors, each including an incident reflector and an exit reflector that are perpendicular to each other. The right-angle mirrors are used to reflect the first laser beam twice.

[0015] Preferably, the grating pair includes an indicator grating and a scale grating, the indicator grating and the right-angle mirror group are disposed on the object being measured, and the indicator grating and the scale grating are arranged parallel to each other.

[0016] Preferably, the indicator grating is positioned below the incident reflector of the right-angle mirror group.

[0017] Preferably, the indicator grating is positioned below the exit reflector of the right-angle mirror group.

[0018] Preferably, the beam splitter uses a non-polarizing beam splitter prism, the first laser beam is aligned with the incident laser beam, and the second laser beam is at an angle to the incident laser beam.

[0019] Preferably, the laser, scale grating, and photoelectric detection component are packaged as a measurement probe, and several measurement probes are distributed outside the right-angle mirror group, which alternately and continuously measure the displacement of the object being measured.

[0020] The beneficial effects of this utility model are as follows:

[0021] By setting up a beam splitter, the second photodetector uses the measured intensity of the second laser beam split by the beam splitter as a constant light intensity. Then, the processor performs illumination compensation on the first laser beam after processing the grating pair, so that the light intensity error measured by the first photodetector is corrected. Attached Figure Description

[0022] Figure 1 The waveform diagram is shown in the existing technology without moiré fringe signal compensation.

[0023] Figure 2 The waveform diagram after moiré fringe signal compensation in this utility model is shown.

[0024] Figure 3 This is a schematic diagram of the structure of this utility model.

[0025] The reference numerals in the attached figures include: 1. the object being measured; 2. the laser; 3. the right-angle mirror group; 4. the indicator grating; 5. the scale grating; 6. the first photodetector; 7. the beam splitter; and 8. the second photodetector. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0027] It should be noted that all actions involving the acquisition of signals, information, or data in this application are carried out in compliance with the relevant data protection laws and policies of the country where the application is located, and with the authorization granted by the owner of the relevant device.

[0028] In this disclosure, unless otherwise stated, directional terms such as "inner" and "outer" are defined based on the contours of the corresponding components. Terms such as "first" and "second" used in this disclosure are for distinguishing one element from another and do not imply sequence or importance.

[0029] Example 1

[0030] like Figures 2-3 As shown, this embodiment provides a light intensity compensated displacement sensor, including a laser 2, a right-angle mirror group 3, a beam splitter 7, a grating pair, a photoelectric detection component and a processor. The beam splitter 7 is disposed between the laser 2 and the right-angle mirror group 3, and the right-angle mirror group 3 is disposed on the object being measured 1.

[0031] Laser 2 is used to emit the incident laser beam;

[0032] Beam splitter 7 is used to receive the incident laser beam and split the incident laser beam into a first laser beam and a second laser beam in proportion.

[0033] Right-angle mirror group 3 is used to receive the first laser beam and then reflect and emit the first laser beam.

[0034] A grating pair is used to generate moiré fringes for the first laser beam;

[0035] The photoelectric detection assembly includes a first photodetector 6 and a second photodetector 8. The first photodetector 6 is used to receive and measure the light intensity of the first laser beam emitted from the grating sub, and the second photodetector 8 is used to receive and measure the light intensity of the second laser beam.

[0036] The processor is used to calculate the light intensity change rate of the second photodetector 8 and the first photodetector 6, compensate the first photodetector 6 according to the transmission-to-reflection ratio of the beam splitter 7, and calculate the displacement of the compensated moiré fringes.

[0037] In this embodiment, by setting up a beam splitter 7, the second photodetector 8 uses the measured intensity of the second laser beam split by the beam splitter 7 as a constant light intensity. After the processor performs illumination compensation on the first laser beam after processing the grating pair, the light intensity error measured by the first photodetector 6 is corrected, and an easily distinguishable moiré fringe signal is obtained.

[0038] The right-angle mirror group 3 includes multiple right-angle mirrors, including mutually perpendicular incident and exit mirrors. The right-angle mirrors are used to reflect the first laser beam twice.

[0039] The right-angle mirror causes the first laser beam to be reflected twice between the two reflective mirrors, which amplifies the displacement of the first laser beam by two times, resulting in higher measurement accuracy. Furthermore, by setting up multiple right-angle mirrors to form a right-angle mirror group 3, the measurement distance is increased.

[0040] Example 2

[0041] like Figure 3 As shown, the grating pair in this embodiment includes an indicator grating 4 and a scale grating 5. The indicator grating 4 and the right-angle mirror group 3 are disposed on the object being measured 1, and the indicator grating 4 and the scale grating 5 are arranged in parallel relative to each other.

[0042] The indicator grating 4 is positioned below the incident mirror of the right-angle mirror group 3. The indicator grating 4 receives the first laser beam that has not yet entered the right-angle mirror for reflection.

[0043] Example 3

[0044] In this embodiment, the beam splitter 7 uses a non-polarizing beam splitter prism. The first laser beam is aligned with the direction of the incident laser beam, while the second laser beam is at an angle to the incident laser beam.

[0045] Preferably, the laser 2, the scale grating 5, and the photoelectric detection component are packaged as a measuring probe, and several measuring probes are distributed outside the right-angle mirror group 3. The several measuring probes alternately and continuously measure the displacement of the object 1 being measured.

[0046] The specific operation method of this utility model is as follows:

[0047] S1. Start laser 2 to emit a laser beam, which is then sent to beam splitter 7 for splitting. The laser beam processed by beam splitter 7 is proportionally dispersed into a first laser beam and a second laser beam.

[0048] S2. The first laser beam is emitted to the right-angle mirror group 3. The first laser beam passes through the right-angle mirror group 3 and the grating pair. The moiré fringes generated by the grating pair are incident on the first photodetector 6. At the same time, the second laser beam is emitted to the second photodetector 8.

[0049] S3. The intensity of the first laser beam measured by the first photodetector 6 is L1, and the intensity of the second laser beam measured by the second photodetector 8 is L2. The light intensity of L1 and L2 is compared.

[0050] S4. The rate of change of L2 is compensated into L1 measured by the first photodetector 6 according to the transmission and reflection ratio of the beam splitter 7.

[0051] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A light intensity compensated displacement sensor, characterized in that, It includes a laser, a right-angle mirror group, a beam splitter, a grating pair, a photoelectric detection component, and a processor. The beam splitter is disposed between the laser and the right-angle mirror group, and the right-angle mirror group is disposed on the object being measured. A laser used to emit an incident laser beam; A beam splitter is used to receive an incident laser beam and split the incident laser beam into a first laser beam and a second laser beam in proportion. A right-angle mirror assembly is used to receive the first laser beam and reflect it twice before emitting it. A grating pair is used to generate moiré fringes for the first laser beam; The photoelectric detection assembly includes a first photodetector and a second photodetector. The first photodetector is used to receive and measure the light intensity of a first laser beam emitted from the grating sub, and the second photodetector is used to receive and measure the light intensity of a second laser beam. The processor is used to calculate the light intensity change rate of the second photodetector and the first photodetector, compensate the first photodetector according to the transmission-to-reflection ratio of the beam splitter, and calculate the displacement of the compensated moiré fringes.

2. The light intensity compensated displacement sensor according to claim 1, characterized in that: The right-angle mirror group includes multiple right-angle mirrors, each including an incident mirror and an exit mirror that are perpendicular to each other. The right-angle mirrors are used to reflect the first laser beam twice.

3. The light intensity compensated displacement sensor according to claim 1, characterized in that: The grating pair includes an indicator grating and a scale grating. The indicator grating and the right-angle mirror group are set on the object being measured, and the indicator grating and the scale grating are arranged parallel to each other.

4. The light intensity compensated displacement sensor according to claim 3, characterized in that: The indicator grating is positioned below the incident reflector of the right-angle mirror group.

5. A light intensity compensated displacement sensor according to claim 1, characterized in that: The beam splitter uses a non-polarized beam splitter prism, with the first laser beam aligned with the incident laser beam and the second laser beam having an angle with the incident laser beam.

6. A light intensity compensated displacement sensor according to any one of claims 1-5, characterized in that: The laser, scale grating, and photoelectric detection components are packaged as a measurement probe. Several measurement probes are distributed outside the right-angle mirror group, and these probes alternately and continuously measure the displacement of the object being measured.

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