Grating ruler

Abstract

The utility model belongs to the technical field of grating rulers, and discloses a grating ruler which comprises a base body and a grating layer. The grating layer comprises a light reflection modulation film, an optical parameter fine adjustment film and a light performance adjustment isolation film; the light reflection modulation film is arranged on one side of the base body, the light performance adjustment isolation film is arranged on one side, far away from the base body, of the light reflection modulation film, and the optical parameter fine adjustment film is arranged between the light reflection modulation film and the light performance adjustment isolation film. According to the utility model, through the multilayer film structure, the reflectivity difference value of bright and dark areas is improved to more than 60%, the response speed and sensitivity of a measurement system are improved, accurate detection of infinitesimal displacement change is realized, and meanwhile, the high reflectivity difference value enables light energy to be more effectively concentrated in the bright area for reflection, so that the loss of light in the grating layer is reduced, and the laser power requirement is reduced; energy consumption is reduced, adverse effects such as a high-power laser heat effect are reduced, system stability is improved, and the service life is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of grating rulers, in particular to a grating ruler. Background Art

[0002] In the current production of grating scales, a single-layer grating layer is usually etched on a substrate. Taking stainless steel as an example, a single-layer stainless steel film is etched on the stainless steel substrate as a grating layer. Although the single-layer grating layer is less difficult to produce during etching and does not require complex multi-layer deposition and interface treatment processes, saving production time and resources, the single-layer grating layer has a low reflectivity difference between the bright and dark areas. Taking a single-layer stainless steel film as the grating layer as an example, the reflectivity difference between the bright and dark areas of the grating layer is only 20% to 30%. The low reflectivity difference will cause the light signal intensity received by the photodetector to change less, making it impossible for the photodetector to capture these weak changes in a timely and accurate manner, thereby reducing the system's response speed and measurement sensitivity. In addition, due to the small reflectivity difference, the laser reflection efficiency is low, resulting in a low contrast of the interference fringes, which requires a higher laser power to obtain sufficient signal intensity, increasing the system's energy consumption. Utility Model Content

[0003] The main purpose of the utility model is to provide a grating ruler, aiming to solve the technical problems that the current grating ruler usually etches a single-layer grating layer on a substrate, resulting in low measurement sensitivity and high system power consumption.

[0004] In order to achieve the above-mentioned purpose of the utility model, the utility model provides a grating ruler, comprising a substrate and a grating layer;

[0005] The grating layer includes a light reflection modulation film, an optical parameter fine adjustment film and an optical performance adjustment isolation film;

[0006] The light reflection modulation film is arranged on one side of the substrate, the optical performance adjustment isolation film is arranged on the side of the light reflection modulation film away from the substrate, and the optical parameter fine-tuning film is arranged between the light reflection modulation film and the optical performance adjustment isolation film.

[0007] Furthermore, the light reflection modulation film is any one of a single-element chromium film, a single-element molybdenum film, a single-element nickel film and a single-element titanium film.

[0008] Furthermore, the optical parameter fine-tuning film is any one of a chromium nitride film, a molybdenum nitride film, a nickel nitride film and a titanium nitride film.

[0009] Furthermore, the optical performance adjustment isolation film is any one of a chromium oxide film, a molybdenum oxide film, a nickel oxide film and a titanium oxide film.

[0010] Furthermore, the grating ruler includes a protective film, and the protective film is arranged on a side of the optical performance adjustment isolation film away from the optical parameter fine-tuning film.

[0011] Furthermore, the thickness of the light reflection modulation film is 10-50 nm, the thickness of the optical parameter fine-tuning film is 20-70 nm, and the thickness of the optical performance adjustment isolation film is 50-110 nm.

[0012] Furthermore, the thickness of the protective film is 10-20 nm.

[0013] Furthermore, the grating ruler also includes a plurality of grating stripes, and the grating stripes are arranged at equal intervals in the light reflection modulation film, the optical parameter fine-tuning film and the optical performance adjustment isolation film.

[0014] Furthermore, the groove depth of the grating stripes is less than or equal to the thickness of the entire grating layer, and the stripe spacing between adjacent grating stripes is 1-100 μm.

[0015] Furthermore, the protective film is made of organic material.

[0016] Beneficial effects:

[0017] The utility model provides a grating ruler, comprising a substrate and a grating layer; the grating layer comprises a light reflection modulation film, an optical parameter fine-tuning film and an optical performance adjustment isolation film; the light reflection modulation film is arranged on one side of the substrate, the optical performance adjustment isolation film is arranged on a side of the light reflection modulation film away from the substrate, and the optical parameter fine-tuning film is arranged between the light reflection modulation film and the optical performance adjustment isolation film. Therefore, a multi-layer film structured grating layer is formed by a light reflection modulation film, an optical parameter fine-tuning film, and an optical performance adjustment isolation film, so that the reflectivity difference between the bright and dark areas can be increased by more than 60%. The high reflectivity difference between the bright and dark areas makes the intensity of the light signal received by the photodetector vary more. When the slight deformation of the microstructure sample causes a slight displacement of the grating scale, the strong light signal change generated by the multi-layer film structured grating layer allows the photodetector to capture these slight changes more sensitively and provide timely feedback on the measurement results, thereby improving the response speed and sensitivity of the entire measurement system, making the detection of slight displacement changes more accurate and reliable. Moreover, due to the high reflectivity difference between the bright and dark areas, the light energy can be more effectively concentrated on the bright area for reflection, reducing the loss of light in the grating layer, so that at a lower laser power input, sufficient intensity of reflected light can be obtained for signal detection and the formation of interference fringes, which not only reduces the energy consumption of the system, but also reduces the adverse effects such as thermal effects that may be caused by high-power lasers, which is conducive to improving the stability and service life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1This is a schematic diagram of the overall layered structure of the grating ruler according to one embodiment of the present invention.

[0019] in:

[0020] 1. Substrate; 2. Grating layer; 3. Protective film; 4. Grating stripes;

[0021] 20. Light reflection modulation film; 21. Optical parameter fine-tuning film; 22. Optical performance adjustment isolation film.

[0022] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0023] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like, indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present invention, "multiple" means two or more, unless otherwise clearly and specifically defined.

[0025] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections, direct connections, or indirect connections through an intermediate medium; they may refer to internal communication between two components or the interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0026] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0027] Reference Figure 1 , this embodiment provides a grating ruler, comprising a substrate 1 and a grating layer 2;

[0028] The grating layer 2 includes a light reflection modulation film 20, an optical parameter fine adjustment film 21 and an optical performance adjustment isolation film 22;

[0029] The light reflection modulation film 20 is arranged on one side of the substrate 1, the optical performance adjustment isolation film 22 is arranged on the side of the light reflection modulation film 20 away from the substrate 1, and the optical parameter fine-tuning film 21 is arranged between the light reflection modulation film 20 and the optical performance adjustment isolation film 22; wherein the material of the substrate 1 is stainless steel.

[0030] In the above embodiment, the grating ruler includes a substrate 1 and a grating layer 2, wherein the substrate 1 is the basic supporting part of the grating ruler. In this embodiment, the material is stainless steel, which provides a stable attachment basis for the grating layer 2 and has good mechanical properties and chemical stability; the grating layer 2 is composed of a multi-layer film structure, including a light reflection modulation film 20, an optical parameter fine-tuning film 21 and an optical performance adjustment isolation film 22. The light reflection modulation film 20 is used to modulate the reflection of light and change the reflection characteristics of light, such as by adjusting the material and thickness of the film to achieve different reflection effects; the optical parameter fine-tuning film 21 can finely adjust various parameters of light, such as wavelength, phase, etc., to meet specific optical performance requirements; the optical performance adjustment isolation film 22 mainly plays the role of adjusting light performance and isolating In order to prevent the mutual influence of light from different areas and optimize the propagation of light in the grating layer 2, the light reflection modulation film 20 is tightly attached to one side surface of the substrate 1. As the first layer of film in direct contact with the substrate 1, the optical parameter fine-tuning film 21 is located on the light reflection modulation film 20. The two are in close contact. Through physical vapor deposition (PVD) or chemical vapor deposition (CVD) and other technologies, the light reflection modulation film 20, the optical parameter fine-tuning film 21 and the optical performance adjustment isolation film 22 are deposited in sequence from bottom to top, and grating stripes 4 are made on the deposited multi-layer film structure. The optical performance adjustment isolation film 22 covers the optical parameter fine-tuning film 21, away from the substrate 1. The design of the multi-layer structure enables the film layers to cooperate with each other to jointly achieve the high performance of the grating scale.

[0031] The multi-layer film structure significantly increases the reflectivity difference between bright and dark areas, which can reach more than 60%, greatly enhancing the contrast of the Moire fringes. In high-precision displacement measurement applications, the measurement accuracy can be improved to a higher level. For example, in the positioning system of semiconductor manufacturing equipment, nanometer-level displacement measurement accuracy can be achieved, meeting the strict requirements for micro-machining accuracy. In addition, the high reflectivity difference increases the amplitude of the light signal intensity change received by the photodetector, making it more sensitive to detecting weak signal changes. In the mechanical properties testing equipment of the microstructure, when the sample undergoes a slight deformation causing a slight displacement of the grating scale, the strong light signal change generated by the multi-layer film structure can allow the photodetector to The detector captures these changes in a timely and accurate manner, improving the response speed and sensitivity of the entire measurement system. The light energy can be more effectively concentrated on the bright area for reflection, reducing the loss of light in the grating layer 2, so that at a lower laser power input, sufficient intensity of reflected light can be obtained for signal detection and the formation of interference fringes. Compared with the traditional single-layer grating ruler, the laser power requirement can be reduced by 40%-60%, which not only reduces the energy consumption of the system, but also reduces the adverse effects such as thermal effects that may be caused by high-power lasers, which is beneficial to improving the stability and service life of the system. It also improves the reliability of the system while reducing energy consumption and reducing maintenance costs.

[0032] Reference Figure 1In one embodiment, the light reflection modulation film 20 is any one of a single chromium film, a single molybdenum film, a single nickel film, and a single titanium film.

[0033] In the above embodiment, the light reflection modulation film 20 can be any one of a single-element chromium film, a single-element molybdenum film, a single-element nickel film, and a single-element titanium film. The single-element chromium film, the single-element molybdenum film, the single-element nickel film, and the single-element titanium film can all reflect and modulate light, providing basic reflective performance for the grating layer 2. They can change the reflection direction and intensity of light, so that the grating can produce the required optical effects, such as forming clear moiré fringes for displacement measurement. In addition, these single-element films all have adjustable reflective properties to a certain extent. By changing factors such as film thickness and deposition conditions, the intensity and direction of the reflected light can be adjusted within a certain range to meet different optical application requirements. As single-element films, they can resist the erosion of external chemicals to a certain extent and protect the internal structure of the grating layer 2.

[0034] Furthermore, the optical parameter fine-tuning film 21 can select any one of chromium nitride film, molybdenum nitride film, nickel nitride film and titanium nitride film. Chromium nitride film, molybdenum nitride film, nickel nitride film and titanium nitride film all have the ability to fine-tune the parameters of light. They can change important parameters such as the wavelength and phase of light, thereby optimizing the propagation and interaction of light in the grating layer 2. For example, in an optical measurement system based on the interference principle, these films can accurately adjust the phase difference of light and improve the measurement precision and accuracy. The nitrides of chromium, molybdenum, nickel and titanium all have a certain chemical stability. They can resist the erosion of external chemicals to a certain extent and protect the internal structure of the grating layer 2. It is very important for the grating scale to work in a complex chemical environment. It can extend the service life of the grating scale and reduce the performance degradation caused by chemical corrosion.

[0035] Furthermore, the optical performance adjustment isolation film 22 can be any one of chromium oxide film, molybdenum oxide film, nickel oxide film and titanium oxide film. Chromium oxide film, molybdenum oxide film, nickel oxide film and titanium oxide film can all adjust the propagation path of light. They can change the refractive index of light so that light propagates in the desired direction in the grating layer 2, thereby optimizing the interference and diffraction effects of light. For example, in the optical system of the grating ruler, these films can ensure the effective propagation of light between different film layers and improve the accuracy of measurement. These oxide films can also adjust the polarization characteristics of light. By changing the polarization state of light, the optical performance of the grating can be further optimized to meet the needs of different application scenarios. These oxide films also have their own physical property advantages. For example, they may have high hardness and wear resistance, which can protect the surface of the grating layer 2 from friction and scratches. At the same time, they may have good thermal stability and can maintain stable optical performance in an environment with large temperature changes, thereby improving the overall stability of the grating layer 2.

[0036] Reference Figure 1 In one embodiment, the grating ruler includes a protective film 3 , and the protective film 3 is arranged on a side of the optical performance adjustment isolation film 22 away from the optical parameter fine-tuning film 21 .

[0037] In the above embodiment, the grating ruler includes a protective film 3, which is a film material covering a specific position of the grating ruler and is used to protect the grating layer 2 from the influence of the external environment. The protective film 3 is located on the side of the optical performance adjustment isolation film 22 away from the optical parameter fine-tuning film 21, that is, the protective film 3 is the outermost layer of film, so that the protective film 3 can directly contact the external environment and play a protective role without interfering with the optical performance adjustment and optical parameter fine-tuning process inside the grating layer 2. The protective film 3 is tightly fitted with the optical performance adjustment isolation film 22 to ensure the effectiveness of its protective effect. The protective film 3 can effectively prevent foreign substances from damaging the grating layer 2. Since its thickness is between 10-20nm, it can be used without significantly affecting light transmission. Under the condition of high temperature and high humidity, the protective film 3 can prevent dust, water vapor, chemicals and other impurities from entering the grating layer 2; the material of the protective film 3 is an organic material; wherein the organic material includes but is not limited to acrylates, polyurethanes, epoxy resins and polyvinyl alcohol. Organic materials such as acrylates, polyurethanes, epoxy resins and polyvinyl alcohol have certain chemical stability and corrosion resistance. When the grating ruler is exposed to an environment containing chemical substances, the protective film 3 can prevent these chemicals from directly contacting the grating layer 2, avoid chemical corrosion from damaging the grating layer 2, and extend the service life of the grating ruler; the existence of the protective film 3 helps to maintain the stability of the optical performance of the grating ruler, and it can reduce the interference of external factors on the grating layer 2, such as preventing the surface damage of the grating layer 2 caused by mechanical friction or scratching.

[0038] Reference Figure 1 In one embodiment, the thickness of the light reflection modulation film 20 is 10-50 nm, the thickness of the optical parameter fine-tuning film 21 is 20-70 nm, and the thickness of the optical performance adjustment isolation film 22 is 50-110 nm.

[0039] In the above embodiment, the thickness of the light reflection modulation film 20 is 10-50nm and the surface roughness is about 0.5-2nm, so that the light reflection modulation film 20 can accurately reflect and modulate the light. The appropriate thickness and roughness range can effectively change the reflection direction and intensity of the light, providing a good foundation for subsequent optical processes. For example, when the grating ruler is used for displacement measurement, it can produce clear Moire fringes and improve measurement accuracy. The thickness of the optical parameter fine-tuning film 21 is 20-70nm, and the surface roughness range is 0.3-1.5nm, so that the optical parameter fine-tuning film 21 can more accurately The optical parameters are adjusted, and the smaller surface roughness reduces interference with the light propagation path, allowing parameters such as wavelength and phase to be more precisely adjusted as light passes through the film layer. This is very important for applications requiring high-precision optical parameter control, such as optical interferometry. The optical performance adjustment isolation film 22 has a thickness of 50-110 nm and a surface roughness range of 0.8-3 nm, enabling it to effectively adjust the optical properties. The appropriate thickness and roughness can change the refractive index, polarization, and other properties of light, optimizing the light propagation path and interference and diffraction effects in the grating layer 2. The thickness and surface roughness design of each film layer facilitates close bonding between the film layers. The thickness and roughness of the light reflection modulation film 20, the optical parameter fine-tuning film 21, and the optical performance adjustment isolation film 22 are mutually adapted, allowing for good interfacial contact between adjacent film layers and reducing interlayer gaps and defects. For example, the slightly smaller surface roughness of the optical parameter fine-tuning film 21 than that of the light reflection modulation film 20 facilitates close adhesion to the light reflection modulation film 20, forming a stable structure.

[0040] Reference Figure 1 In one embodiment, the grating scale further includes a plurality of grating stripes 4, and the grating stripes 4 are arranged at equal intervals within the light reflection modulation film 20, the optical parameter fine-tuning film 21 and the optical performance adjustment isolation film 22.

[0041] In the above embodiment, the grating ruler also includes a plurality of grating stripes 4. The grating stripes 4 are periodically arranged structures on the grating ruler. They realize displacement measurement by diffraction and interference of light. The plurality of grating stripes 4 are arranged at equal intervals within the light reflection modulation film 20, the optical parameter fine adjustment film 21, and the optical performance adjustment isolation film 22. This means that the grating stripes 4 penetrate these three layers of film and are closely integrated with them. The groove depth of the grating stripes 4 is less than or equal to the thickness of the entire grating layer 2 (composed of three layers of film), which ensures the reasonable placement of the grating stripes 4 in the grating layer 2. Embedding will not destroy the film structure. The stripe spacing between adjacent grating stripes 4 is between 1-100μm, among which the stripe spacing is preferably 20μm, 30μm, 35μm, and 45μm. The width of the grating stripe 4 is also between 1-100μm, among which the stripe width is preferably 20μm, 30μm, 35μm, and 45μm. This size design is closely related to the optical performance and measurement accuracy of the grating layer 2. The grating stripes 4 are equidistantly arranged in the multilayer film, combined with the functions of each film layer, which significantly improves the optical performance of the grating ruler. The light reflection modulation film 20 provides basic reflection modulation for the grating stripes 4, the optical parameter fine-tuning film 21 further fine-tunes the optical parameters, and the optical performance adjustment isolation film 22 ensures the stable propagation of light, so that the light diffraction and interference effects at the grating stripes 4 are better. In the optical measurement system, it can improve the measurement resolution and accuracy, and more accurately detect small displacements. The reasonable stripe spacing and width design, as well as the grating duty cycle in the range of 0.01-0.99, enable the grating scale to adapt to different measurement requirements. Narrower stripe spacing and width can improve the measurement sensitivity, while a larger duty cycle can improve the utilization efficiency of light in some applications, thereby optimizing the measurement results.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A grating ruler, characterized in that: including a substrate and a grating layer; The grating layer includes a light reflection modulation film, an optical parameter fine adjustment film and an optical performance adjustment isolation film; The light reflection modulation film is arranged on one side of the substrate, the optical performance adjustment isolation film is arranged on the side of the light reflection modulation film away from the substrate, and the optical parameter fine-tuning film is arranged between the light reflection modulation film and the optical performance adjustment isolation film.

2. The grating ruler according to claim 1, characterized in that The light reflection modulation film is any one of a single-element chromium film, a single-element molybdenum film, a single-element nickel film, and a single-element titanium film.

3. The grating ruler according to claim 1, characterized in that The optical parameter fine-tuning film is any one of a chromium nitride film, a molybdenum nitride film, a nickel nitride film and a titanium nitride film.

4. The grating ruler according to claim 1, characterized in that The optical performance adjustment isolation film is any one of a chromium oxide film, a molybdenum oxide film, a nickel oxide film and a titanium oxide film.

5. The grating ruler according to claim 1, characterized in that: The grating scale includes a protective film, which is arranged on a side of the optical performance adjustment isolation film away from the optical parameter fine-tuning film.

6. The grating ruler according to claim 1, characterized in that The thickness of the light reflection modulation film is 10-50 nm, the thickness of the optical parameter fine-tuning film is 20-70 nm, and the thickness of the optical performance adjustment isolation film is 50-110 nm.

7. The grating ruler according to claim 5, characterized in that The thickness of the protective film is 10-20 nm.

8. The grating ruler according to claim 1, characterized in that The grating scale also includes a plurality of grating stripes, and the grating stripes are arranged at equal intervals within the light reflection modulation film, the optical parameter fine-tuning film and the optical performance adjustment isolation film.

9. The grating ruler according to claim 8, characterized in that: The groove depth of the grating stripes is less than or equal to the thickness of the entire grating layer, and the stripe spacing between adjacent grating stripes is 1-100 μm.

10. The grating ruler according to claim 5, characterized in that: The material of the protective film is organic material.

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