Grating position sensor

Abstract

The invention relates to the technical field of sensors, and provides a grating position sensor. A scanning assembly and a light source module are relatively fixed, and an incident diaphragm and an increment detector are arranged in the scanning assembly; the increment detector is spatially divided into at least two first detector regions for detecting a first phase increment signal component and at least two second detector regions for detecting a second phase increment signal component, and the at least two first detector regions are spatially separated from each other; performing redundant detection on the first phase increment signal component; the at least two second detector areas are separated from each other in space so as to perform redundancy detection on the second phase increment signal component; the position metering element is suitable for being fixed on a measured object or a measuring datum plane and can generate relative displacement with the scanning assembly. The invention provides a grating position sensor with strong anti-pollution capability. The grating position sensor can keep a high-reliability working state for a long time in a complex or severe industrial environment.

Description

Technical Field

[0001] This invention relates to the field of sensor technology, and in particular to a grating position sensor employing the principle of optical interference. Background Technology

[0002] As modern industry develops towards high precision and sophistication, fields such as precision manufacturing, semiconductor equipment, and automated assembly are placing unprecedented demands on the accuracy of displacement and position measurements. Position sensors are used to monitor minute positional changes of critical components or to provide high-precision real-time position feedback for moving parts, and are one of the core components ensuring the overall performance, accuracy, and long-term stability of equipment.

[0003] Among various position sensors, grating position sensors are widely used due to their high resolution, high accuracy, non-contact measurement, and miniaturization potential. They utilize the diffraction and interference effects of a grating on a light beam to measure displacement.

[0004] However, existing grating position sensors are often designed to operate in clean or controlled environments by default. As application scenarios continue to expand, sensors will inevitably be exposed to environments containing potential contaminants such as dust, oil, and moisture. When contaminants adhere to the surface of the grating ruler, they can obstruct or interfere with the optical path, leading to a decrease in the amplitude of the incremental signal, a deterioration in the signal-to-noise ratio, and even incorrect counting. Summary of the Invention

[0005] This invention provides a grating position sensor to address at least one of the aforementioned deficiencies in the prior art. It provides a grating position sensor with strong anti-contamination capabilities, which can maintain a highly reliable working state for a long time in complex or harsh industrial environments, thereby overcoming the defect in the prior art where the performance of grating sensors degrades or fails due to dirt on the grating scale in non-clean environments.

[0006] This invention provides a grating position sensor, comprising: Light source module; A scanning component is fixed relative to the light source module. The scanning component contains an incident aperture and an incremental detector. The incident aperture is used to shape the incident light generated by the light source module. The incremental detector is spatially divided into at least two first detector regions for detecting a first phase increment signal component and at least two second detector regions for detecting a second phase increment signal component. The at least two first detector regions are spatially separated to redundantly detect the first phase increment signal component. The at least two second detector regions are also spatially separated to redundantly detect the second phase increment signal component. The position measuring element is suitable for being fixed to the object being measured or the measuring reference surface, and can generate relative displacement with the scanning component.

[0007] According to the grating position sensor provided by the present invention, there is a 90° phase difference between the first phase increment signal component and the second phase increment signal component.

[0008] According to the grating position sensor provided by the present invention, there is a physical deviation in the arrangement of detectors in the first detector region and the second detector region, so that a 90° phase difference is generated between the signal components detected by the two regions.

[0009] According to the grating position sensor provided by the present invention, each of the first detector regions includes at least one pair of first sub-detectors and second sub-detectors for generating differential signals; And / or, each of the second detector regions includes at least one pair of third and fourth sub-detectors for generating differential signals.

[0010] According to the grating position sensor provided by the present invention, the position measuring element has an incremental code channel for generating an incremental signal and a zero code channel for generating a zero position signal.

[0011] According to the grating position sensor provided by the present invention, the incremental code track is composed of a one-dimensional linear grating with a fixed period; The zero-position code track is composed of a one-dimensional curved grating with a fixed period.

[0012] According to the grating position sensor provided by the present invention, the period of the incremental code channel is Tz, and the period of the zero code channel is Tl, wherein: Tz>2Tl.

[0013] According to the grating position sensor provided by the present invention, the scanning assembly is further provided with a zero-position detector, which is used to receive the zero-position signal generated by the zero-position code track.

[0014] According to the grating position sensor provided by the present invention, the light source module includes a light-emitting diode or a vertical cavity surface-emitting laser.

[0015] This invention provides a grating position sensor, comprising: The position measuring element has an incremental code track composed of a one-dimensional linear grating with a period of Tz and a zero-position code track composed of a one-dimensional curved grating with a period of Tl. A scanning component is used to detect the incremental signal generated by the incremental code track and the zero signal generated by the zero code track; And a signal processing circuit, used to determine the zero position based on the peak value of the zero signal generated by the zero code channel and the intensity change of the incremental signal generated by the incremental code channel at the corresponding position.

[0016] The grating position sensor provided by this invention achieves its anti-contamination capability through the redundancy and spatial separation design of the incremental detector. Specifically, by setting multiple spatially separated detector regions on the incremental detector to detect in-phase signal components separately, when one or more detector regions are obstructed by contaminants, the other unaffected regions can still output valid signals normally. The signal processing circuit can ignore the contaminated signal or perform a weighted average of multiple signals, thereby ensuring that even when there is localized contamination on the position measuring element (grating ruler), the grating position sensor can still stably output a high-quality incremental signal, improving the environmental adaptability and operational reliability of the grating position sensor.

[0017] Furthermore, a curved grating is used as the null code channel. Utilizing its beam-converging properties, the diffracted light energy is more concentrated on the null detector, forming a spot with higher energy density. This not only improves the intensity and signal-to-noise ratio of the null signal but also reduces stray light interference from the incremental code channel. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the optical path structure of the grating position sensor provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram of the scanning component in the grating position sensor provided in an embodiment of the present invention.

[0021] Figure 3 This is a schematic diagram of the position measuring element in the grating position sensor provided in an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the layout of the incremental detector in the grating position sensor provided in an embodiment of the present invention.

[0023] Figure 5This is a schematic diagram of the timing relationship between the incremental signal and the zero-position signal in the grating position sensor provided in this embodiment of the invention (the top is the periodic incremental signal, and the bottom is a Gaussian zero-position pulse signal output by the zero-position detector when the beam sweeps across the zero-position code track).

[0024] Figure label: 10. Light source module; 20. Scanning assembly; 21. Incident aperture; 22. Incremental detector; 221. First detector region; 221-1. First sub-detector; 221-2. Second sub-detector; 222. Second detector region; 222-1. Third sub-detector; 222-2. Fourth sub-detector; 23. Zero-position detector; 30. Position measuring element; 31. Incremental code track; 32. Zero position code track. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0026] In the description of the embodiments of this application, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of this application based on the specific circumstances.

[0027] In the embodiments of this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the embodiments of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0029] Figure 1 This is a schematic diagram of the optical path structure of the grating position sensor provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the scanning component in the grating position sensor provided in an embodiment of the present invention. Figure 3 This is a schematic diagram of the position measuring element in the grating position sensor provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of the layout of the incremental detector in the grating position sensor provided in an embodiment of the present invention.

[0030] See Figures 1 to 4 This invention provides a grating position sensor, a device for precise displacement measurement using optical principles. The grating position sensor mainly consists of a light source module 10, a scanning component 20, and a position measuring element 30, wherein the scanning component 20 and the position measuring element 30 are movable relative to each other.

[0031] The light source module 10 is used to provide illumination light for the entire grating position sensor. The light source module 10 can be a light-emitting diode (LED), a vertical-cavity surface-emitting laser (VCSEL), or other suitable light source. Preferably, the light source module 10 has a certain spatial expansion to form a uniform light field, ensuring stable illumination of a sufficiently large area on the position measuring element 30.

[0032] The position measuring element 30 is a reference ruler that carries position information, commonly referred to as a scale grating or grating ruler. The position measuring element 30 is suitable for fixing to the object being measured or the measurement reference surface, and can generate relative displacement with the scanning assembly 20. The surface of the position measuring element 30 is formed with a precise engraved pattern, i.e., a code track.

[0033] The position measuring element 30 includes an incremental code track 31 for generating incremental signals and a zero-position code track 32 for generating zero-position signals. The incremental code track 31 is typically a one-dimensional linear grating with a fixed period. When a light beam illuminates and sweeps across the incremental code track 31, a periodically changing incremental signal is generated for high-resolution displacement measurement. The zero-position code track 32 is used to generate an absolute reference position signal, i.e., a zero-position signal. The zero-position code track 32 can be a special pattern, such as a one-dimensional curved grating with a fixed period, used for zeroing upon startup or eliminating accumulated errors.

[0034] The scanning assembly 20 includes optical transmitting and receiving sections for reading information from the position measuring element 30, and is commonly referred to as a reading head. The scanning assembly 20 internally includes an incident aperture 21, an increment detector 22, and a zero-position detector 23.

[0035] The incident aperture 21 is located between the light source module 10 and the position measuring element 30. Its function is to perform spatial filtering and shaping on the light beam emitted by the light source, and to limit the size and shape of the light spot illuminating the code track in order to optimize the diffraction effect.

[0036] The zero-position detector 23 is an independent photodetector that is spatially aligned with the diffraction optical path of the zero-position code channel 32 and is specifically designed to receive and convert zero-position signals.

[0037] The incremental detector 22 is the core innovation of this invention. It is a photodetector array used to receive diffracted light from the incremental code channel 31 and detect interference signals. The incremental detector 22 is spatially divided into at least two first detector regions 221 for detecting the first phase incremental signal component and at least two second detector regions 222 for detecting the second phase incremental signal component. The at least two first detector regions 221 are spatially separated to redundantly detect the first phase incremental signal component; similarly, the at least two second detector regions 222 are spatially separated to redundantly detect the second phase incremental signal component.

[0038] Essentially, to enable the grating position sensor to be used in environments with potential contaminants, this invention aims to prevent contaminants from adhering to the surface of the grating ruler, which could obstruct or interfere with the optical path, leading to a decrease in the amplitude of the incremental signal, a deterioration in the signal-to-noise ratio, or even false counting. The invention creatively divides the incremental detector 22 into multiple spatially separated detector regions.

[0039] In order to determine the direction of motion and to subdivide the signal to improve resolution, grating position sensors typically need to detect at least two signals with a phase difference (usually 90°), namely sine (Sin) and cosine (Cos) signals, corresponding to the first phase increment signal component and the second phase increment signal component, respectively.

[0040] Specifically, the incremental detector 22 is divided into two first detector regions 221 and two second detector regions 222. The first detector regions 221A and 221B are spatially separated and are used to detect signal components of the same phase (e.g., a sine signal), constituting redundant detection of that signal component. In other words, the first detector regions 221A and 221B, or two or more regions, are physically designed to detect signal components of the same phase (e.g., a sine signal).

[0041] Similarly, the second detector region 222A and the second detector region 222B are also spatially separated and are used together to detect signal components of another phase (e.g., Cos signals), thus constituting redundant detection. In other words, the second detector region 222A and the second detector region 222B, or two or more regions, are also physically designed to detect signal components of another phase (e.g., Cos signals).

[0042] The spatial separation can be understood as follows: multiple detector regions (such as detector region A and detector region B) used to detect the same phase signal are not adjacent on the chip of incremental detector 22, but rather have a significant physical distance between them. They are distributed at different locations on the chip of incremental detector 22. As a result of this arrangement, the light they receive comes from reflections / diffractions from different regions on the position metering element 30.

[0043] Redundant detection is the core means by which this invention achieves anti-contamination capability. Its operation is as follows: Taking the first phase increment signal component (Sin signal) as an example, it is jointly detected by the first detector region 221A and the first detector region 221B. In an ideal clean environment, the first detector region 221A and the first detector region 221B will output signals with essentially the same amplitude and phase. The signal processing circuit can combine them, for example, by averaging, to enhance the signal-to-noise ratio.

[0044] When localized contamination (such as dust or oil stains) appears on the surface of the position measuring element 30, it is assumed that the contaminant happens to block the light path illuminating the first detector region 221A. In conventional designs, this would directly lead to distortion or disappearance of the Sin signal, causing sensor failure.

[0045] In this embodiment of the invention, since there is another detector region B with the same function but separated by space, and its corresponding optical path is located at a different position on the grating ruler, the optical path may not be blocked. Therefore, even if the signal of the first detector region 221A fails, the signal processing circuit can still obtain a complete and high-quality Sin signal from the first detector region 221B.

[0046] Similarly, redundant detection of the second phase increment signal component (Cos signal) follows the same principle. As long as the contaminant is not large enough to simultaneously cover all first detector regions 221 (A and B) or all second detector regions 222 (A and B), the grating position sensor can continue to operate normally, thus achieving the grating position sensor's anti-contamination capability to maintain normal operation in the presence of local contamination.

[0047] It should be noted that, in the embodiments of the present invention, redundant detection and spatially separated arrangement should not be understood in isolation as any form of arrangement or combination of multiple detectors. Rather, it should be interpreted as a functional structure with a specific technical purpose: through a physically separated layout, backup detection of the same phase signal is achieved, so that when a signal channel is interrupted due to contamination, a backup channel is still available, ultimately achieving the invention's objective of anti-contamination.

[0048] Based on the above detailed description, those skilled in the art can clearly understand that in order to realize the present invention, when designing a photodetector chip, it is necessary to arrange multiple photosensitive unit groups (regions) for generating Sin signals and multiple photosensitive unit groups (regions) for generating Cos signals in a distributed and decentralized manner on the chip, and design corresponding signal processing logic to select or fuse these redundant signals.

[0049] In the operation of the grating position sensor provided in this embodiment of the invention, the light beam emitted by the light source module 10 is shaped by the incident aperture 21 inside the scanning assembly 20 and then illuminates the code track of the position measuring element 30. The light beam undergoes diffraction or reflection on the code track, and the light beam carrying position information returns to the scanning assembly 20, where it is received by the incremental detector 22 and the zero-position detector 23. When the scanning assembly 20 and the position measuring element 30 undergo relative displacement, the light intensity received by the detector will change periodically (e.g., sine or cosine) as an incremental signal. By processing these light signals, the accurate displacement value can be calculated.

[0050] For example, when the light beam shines on the incremental code channel 31, diffraction occurs. The ±1st order diffracted light and the 0th order diffracted light return to the scanning component 20 and interfere on the surface of the incremental detector 22, forming alternating bright and dark interference fringes.

[0051] When the beam scans to the zero-position code channel 32, since the zero-position code channel 32 is a curved grating, it not only diffracts / deflects the beam but also has a lens effect, which can converge the diffracted beam into a line or dot-shaped light spot, illuminating the independent zero-position detector 23. This converging effect makes the energy density of the zero-position signal much higher than that of the diffuse incremental signal background light, thereby obtaining a zero-position pulse signal with an extremely high signal-to-noise ratio.

[0052] It is understood that the grating position sensor provided in this embodiment of the invention achieves its anti-fouling capability through the redundancy and spatial separation design of the incremental detector 22. Specifically, by setting multiple spatially separated detector regions on the incremental detector 22 to detect in-phase signal components separately, when one or more detector regions are obscured by contaminants, the other unaffected regions can still output valid signals normally. The signal processing circuit can ignore the contaminated signal or perform a weighted average of multiple signals, thereby ensuring that even when there is localized dirt on the position measuring element 30 (grating ruler), the grating position sensor can still stably output a high-quality incremental signal, improving the environmental adaptability and operational reliability of the grating position sensor.

[0053] Furthermore, by employing a curved grating as the null code channel 32, and utilizing its beam-converging properties, the diffracted light energy is more concentrated on the null detector 23, forming a light spot with higher energy density. This not only improves the intensity and signal-to-noise ratio of the null signal, but also reduces stray light interference from the incremental code channel 31.

[0054] Continue reading Figure 4 In some embodiments of the present invention, a 90° phase difference exists between the first phase increment signal component and the second phase increment signal component. This further defines the electrical characteristic relationship between the two increment signal components detected by the first detector region 221 and the second detector region 222.

[0055] Specifically, these two signals are orthogonal in time (or displacement), meaning that when one signal (e.g., the Sin signal) is at its peak or trough, the other signal (e.g., the Cos signal) is exactly at its zero point, and vice versa. Such signals with a 90° (or π / 2) phase difference are commonly referred to as orthogonal signals. Generating orthogonal signals is crucial for achieving high-precision measurements in grating position sensors.

[0056] By determining the leading or lagging relationship between the two signals, the relative motion direction between the scanning component 20 and the position measuring element 30 can be determined. For example, when the first phase increment signal component (Sin) leads the second phase increment signal component (Cos) by 90°, it may represent forward motion; conversely, it represents reverse motion.

[0057] Multiple or even hundreds of position points can be interpolated within one period of the incremental signal. Even if the physical marking period of the grating ruler (e.g., 20 micrometers) is fixed, by electronically subdividing the 90° orthogonal signal, a measurement resolution far exceeding the physical period (down to the nanometer level) can be obtained.

[0058] Continue reading Figure 4In some embodiments of the present invention, the detectors in the first detector region 221 and the second detector region 222 are physically misaligned to create a 90° phase difference between the signal components detected by the two regions. It is explicitly stated that this phase difference is achieved by spatially misaligning the different detector regions on the detector chip. Here, "physical misalignment" does not refer to manufacturing error, but rather to a deliberate design offset.

[0059] Those skilled in the art will understand that when the scanning assembly 20 and the position measuring element 30 move relative to each other, alternating bright and dark moving interference fringes are formed on the surface of the incremental detector 22. These fringes have a spatial period, which we call P. The phase change of one period is 360°. To generate a 90° phase difference, it is only necessary to shift the detector area used to detect the second phase increment signal component (Cos) relative to the detector area used to detect the first phase increment signal component (Sin) along the moving direction of the interference fringes by a distance of one-quarter (1 / 4) of a fringe period, i.e., physical deviation = P / 4.

[0060] With this configuration, when the Sin region detects the center of a bright fringe (0° or 360° phase), the Cos region detects the boundary between bright and dark areas (90° or 270° phase), thus naturally ensuring a stable 90° phase difference between the output signals.

[0061] Continue reading Figure 4 In some embodiments of the present invention, each first detector region 221 includes at least one pair of first sub-detectors 221-1 and second sub-detectors 221-2 for generating differential signals; and / or, each second detector region 222 includes at least one pair of third sub-detectors 222-1 and fourth sub-detectors 222-2 for generating differential signals, further optimizing the microstructure inside each detector region.

[0062] That is, each region (whether used to detect Sin or Cos signals) consists of at least one pair of sub-detectors designed for differential signal detection. The main purpose of differential detection is to suppress common-mode noise, thereby significantly improving the signal-to-noise ratio (SNR) and measurement stability.

[0063] Specifically, in the arrangement of a pair of sub-detectors (e.g., the first sub-detector 221-1 and the second sub-detector 221-2), the received optical signals are arranged so that they are 180° out of phase. This can also be achieved through physical offset, i.e., making the spatial distance between them half the period of the interference fringe (P / 2). In this way, when the first sub-detector 221-1 detects the brightest point, the second sub-detector 221-2 happens to detect the darkest point.

[0064] Continue reading Figure 3 In some embodiments of the present invention, the period of the incremental code channel 31 is Tz, and the period of the zero code channel 32 is Tl, wherein Tz > 2Tl. The large period difference allows the diffracted light of the incremental code channel 31 and the diffracted light of the zero code channel 32 to be separated on the detector surface, thereby reducing mutual interference.

[0065] Figure 5 This is a schematic diagram of the timing relationship between the incremental signal and the zero-position signal in the grating position sensor provided in this embodiment of the invention (the top is the periodic incremental signal, and the bottom is a Gaussian zero-position pulse signal output by the zero-position detector 23 when the beam sweeps across the zero-position code track 32).

[0066] See Figure 5 The present invention also provides a grating position sensor, which includes a position measuring element 30, a scanning component 20, and a signal processing circuit.

[0067] The position measuring element 30 has an incremental code track 31 composed of a one-dimensional linear grating with a period of Tz and a zero-position code track 32 composed of a one-dimensional curved grating with a period of Tl. The scanning component 20 is used to detect the incremental signal generated by the incremental code track 31 and the zero-position signal generated by the zero-position code track 32. The signal processing circuit is used to determine the zero-position position based on the peak value of the zero-position signal generated by the zero-position code track 32 and the intensity change of the incremental signal generated by the incremental code track 31 at the corresponding position.

[0068] By setting one or more zero-point marks on the grating ruler, an absolute reference point can be provided during measurement. This is crucial for zeroing upon power-on, eliminating accumulated errors, and ensuring the accuracy and repeatability of long-term measurements. The accuracy of zero-point determination directly affects the reliability of the entire grating position sensor.

[0069] In this embodiment of the invention, a dual verification mechanism is added to the zero-position confirmation by using a method that coordinates the determination of incremental signal strength and the peak value of the zero-position signal. Only when the zero-position signal reaches its peak value and the incremental signal strength exhibits the expected characteristic change is it confirmed as a valid zero position. This method effectively filters out false zero-position signals caused by noise or interference, ensuring the uniqueness and accuracy of the zero-position determination.

[0070] Understandably, traditional methods determine the occurrence of a zero-position pulse by setting a threshold. However, this method is susceptible to noise interference. In contrast, this invention uses a method that combines incremental signal intensity and zero-position signal peak value for determination. When the light beam passes through the zero-position code channel 32, some of the light energy is diffracted by the zero-position code channel 32 to the zero-position detector 23, resulting in a corresponding reduction in the energy reaching the incremental detector 22. This causes a noticeable dip or valley in the envelope (intensity) of the incremental signal at that position.

[0071] The signal processing circuit of this invention utilizes this phenomenon. Its determination logic is configured such that the true zero position is finally confirmed only when the zero-position detector 23 detects a signal peak and the signal strength output by the incremental detector 22 exhibits a preset valley characteristic at the same or very close moments. This dual-safety mechanism effectively eliminates false zero-position signals caused by electrical noise and other reasons, greatly improving the reliability and accuracy of zero-position determination.

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A grating position sensor, characterized in that, include: Light source module; A scanning component is fixed relative to the light source module. The scanning component contains an incident aperture and an incremental detector. The incident aperture is used to shape the incident light generated by the light source module. The incremental detector is spatially divided into at least two first detector regions for detecting a first phase increment signal component and at least two second detector regions for detecting a second phase increment signal component. The at least two first detector regions are spatially separated to redundantly detect the first phase increment signal component. The at least two second detector regions are also spatially separated to redundantly detect the second phase increment signal component. The position measuring element is suitable for being fixed to the object being measured or the measuring reference surface, and can generate relative displacement with the scanning component.

2. The grating position sensor according to claim 1, characterized in that, There is a 90° phase difference between the first phase increment signal component and the second phase increment signal component.

3. The grating position sensor according to claim 2, characterized in that, There is a physical deviation in the arrangement of detectors in the first detector region and the second detector region, so that there is a 90° phase difference between the signal components detected by the two regions.

4. The grating position sensor according to claim 1, characterized in that, Each of the first detector regions includes at least one pair of first and second sub-detectors for generating differential signals; And / or, each of the second detector regions includes at least one pair of third and fourth sub-detectors for generating differential signals.

5. The grating position sensor according to claim 1, characterized in that, The position measuring element has an incremental code channel for generating incremental signals and a zero code channel for generating zero signals.

6. The grating position sensor according to claim 5, characterized in that, The incremental code track is composed of a one-dimensional linear grating with a fixed period; The zero-position code track is composed of a one-dimensional curved grating with a fixed period.

7. The grating position sensor according to claim 6, characterized in that, The period of the incremental code channel is Tz, and the period of the zero code channel is Tl, where Tz > 2Tl.

8. The grating position sensor according to claim 5, characterized in that, The scanning component is also equipped with a zero-position detector, which is used to receive the zero-position signal generated by the zero-position code track.

9. The grating position sensor according to any one of claims 1 to 8, characterized in that, The light source module includes a light-emitting diode or a vertical-cavity surface-emitting laser.

10. A grating position sensor, characterized in that, include: The position measuring element has an incremental code track composed of a one-dimensional linear grating with a period of Tz and a zero-position code track composed of a one-dimensional curved grating with a period of Tl. A scanning component is used to detect the incremental signal generated by the incremental code track and the zero signal generated by the zero code track; And a signal processing circuit, used to determine the zero position based on the peak value of the zero signal generated by the zero code channel and the intensity change of the incremental signal generated by the incremental code channel at the corresponding position.

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