CN110907140A - Device and method for measuring grating period - Google Patents
Device and method for measuring grating period Download PDFInfo
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- CN110907140A CN110907140A CN201911169297.3A CN201911169297A CN110907140A CN 110907140 A CN110907140 A CN 110907140A CN 201911169297 A CN201911169297 A CN 201911169297A CN 110907140 A CN110907140 A CN 110907140A
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- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000009434 installation Methods 0.000 claims description 4
- 238000012423 maintenance Methods 0.000 abstract description 5
- 238000005259 measurement Methods 0.000 description 14
- 238000010586 diagram Methods 0.000 description 11
- 230000003287 optical effect Effects 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
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- 238000002050 diffraction method Methods 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M11/00—Testing of optical apparatus; Testing structures by optical methods not otherwise provided for
- G01M11/02—Testing optical properties
- G01M11/0207—Details of measuring devices
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Abstract
The application provides a device and a method for measuring grating period. In the device, the cascade grating can be arranged above the light source, and the mounting seats can be positioned on two opposite side edges in the cascade grating and used for mounting the grating to be tested. Therefore, the light emitted by the light source is emitted from the bottom surface of the cascade grating, emitted from the top surface of the cascade grating, emitted from the bottom surface of the grating to be detected and emitted from the top surface of the grating to be detected. The interference pattern formed after light penetrates through the cascade grating and the grating to be detected can be observed through the observation window arranged above the grating to be detected, and the camera arranged above the grating to be detected is adopted to shoot the interference pattern, so that an experimenter can determine the period of the grating to be detected according to the shot interference pattern. The whole device is simple in structure, the period of the grating to be measured can be measured only by using the cascade grating, and the difficulty of use and daily maintenance is greatly reduced.
Description
Technical Field
The present disclosure relates to the field of optical technologies, and in particular, to a device and a method for measuring a grating period.
Background
The grating is an optical device composed of a large number of parallel slits of equal width and equal spacing, and can be classified into an intensity grating and a phase grating according to the modulation of light. The grating disperses light with different wavelengths mainly through the diffraction characteristics of the grating, so that the wavelength of the light is accurately measured.
At present, the measurement of the grating period mainly includes an interferometric method, a moire fringe method, a long-range profilometer method, a diffraction method and the like. However, in most conventional grating period measuring devices, interference fringes are obtained by emitting laser beams from a laser, and the grating period is calculated. The structure of the measuring device for the grating period of the structure is complicated due to the introduction of the laser, and the difficulty of use and daily maintenance of the measuring device is increased.
Based on this, there is a need for a grating period measuring device, which is used to simplify the grating period measuring device.
Disclosure of Invention
The application provides a grating period measuring device and a method, which can be used for solving the technical problems that the grating period measuring device in the prior art is complex in structure and difficult to use and maintain in daily life.
In a first aspect, an embodiment of the present application provides a device for measuring a grating period, where the device 100 includes a base 101 and a light source 102 located on the base 101; the device 100 further comprises a cascade grating 103, a mounting seat 104, an observation window 105 and a camera 106;
the cascade grating 103 is installed above the light source 102, and light emitted by the light source 102 enters from the bottom surface of the cascade grating 103 and exits from the top surface of the cascade grating 103; the cascade grating 103 is formed by cascading a plurality of fan-shaped gratings; wherein the minimum period of the fan-shaped grating is' Lambda1", the maximum period is" "A2"；
The mounting seats 104 are located on two opposite side edges of the cascade grating 103 and used for mounting a grating 107 to be tested; the grating 107 to be tested is arranged above the cascade grating 103 after being installed, and light rays emitted by the light source 102 are emitted from the top surface of the cascade grating 103, then emitted from the bottom surface of the grating 107 to be tested, and emitted from the top surface of the grating 107 to be tested;
the observation window 105 is installed above the grating 107 to be measured and is used for observing an interference pattern formed after light penetrates through the cascade grating 103 and the grating 107 to be measured;
the camera 106 is installed above the grating 107 to be measured, is close to the observation window 105, is located at the same height as the observation window 105, and is used for shooting the interference pattern, so that an experimenter can determine the period of the grating 107 to be measured according to the shot interference pattern.
Optionally, the interference pattern is moire fringes;
the cascade grating 103 is provided with scale values, and the scale values are numerical values corresponding to the centers of the moire fringes.
Optionally, when the grating 107 to be measured is a phase grating to be measured, the apparatus 100 further includes a first polarizer 108 and a second polarizer 109;
the first polarizer 108 is located below the cascade grating 103, and light emitted by the light source 102 enters the cascade grating 103 after exiting from the bottom surface of the first polarizer 108 and the top surface of the first polarizer 108;
the second polarizer 109 is located below the grating to be tested 107, and after the light emitted by the light source 102 is emitted from the top surface of the cascade grating 103, the light is emitted from the bottom surface of the second polarizer 109, emitted from the top surface of the second polarizer 109, emitted from the bottom surface of the grating to be tested 107, and emitted from the top surface of the grating to be tested 107.
Optionally, the apparatus 100 further includes a first vertical column 110, a second vertical column 111, and a cross beam 112, where the heights of the first vertical column 110 and the second vertical column 111 are both higher than the position of the top surface of the grating 107 to be measured;
one end of the first upright 110 is fixedly connected with the first side surface of the base 101, and the other end is connected with one end of the cross beam 112;
one end of the second upright 111 is fixedly connected with a second side surface of the base 101 opposite to the first side surface, and the other end is connected with the other end of the cross beam 112;
the observation window 105 and the camera 106 are respectively mounted on the beam 112.
Optionally, the apparatus 100 further comprises a slider 113;
the sliding block 113 is nested on the cross beam 112 and moves along the length direction of the cross beam 112;
the observation window 105 is connected with the sliding block 113, is mounted on the cross beam 112 through the sliding block 113, and is driven by the sliding block 113 to move along the length direction of the cross beam 112;
the camera 106 is connected with the sliding block 113, is mounted on the beam 112 through the sliding block 113, and is driven by the sliding block 113 to move along the length direction of the beam 112.
Optionally, the device 100 further comprises a first connector 114 and a second connector 115;
the other end of the first upright 110 is connected with one end of the cross beam 112 through the first connecting piece 114, and the other end of the second upright 111 is connected with the other end of the cross beam 112 through the second connecting piece 115;
the height of the cross beam 112 is adjusted by adjusting the connection position of the first connection member 114 and the cross beam 112 and the connection position of the second connection member 115 and the cross beam 112.
Optionally, the base 101 is a hollow structure;
the light source 102 is located in the hollow structure of the base 101.
Optionally, the size of the bottom surface of the cascade grating 103 is matched with the size of the light emitting surface of the light source 102;
the size of the bottom surface of the grating to be measured 107 is smaller than or equal to the size of the bottom surface of the cascade grating 103.
Optionally, the mount 104 is a rail;
the grating 107 to be measured moves along the guide rail 116.
In a second aspect, the present application provides a method for measuring a grating period, which is applied to the above-mentioned measuring apparatus 100 for a grating period; the method comprises the following steps:
installing a grating 107 to be tested on the mounting base 104;
turning on the light source 102;
observing an interference pattern formed after light penetrates through the cascade grating 103 and the grating to be detected 107 through the observation window 105;
and shooting the interference pattern by using a camera 106, and determining the period of the grating 107 to be measured according to the shot interference pattern.
By adopting the grating period measuring device provided by the embodiment of the application, the cascade grating can be arranged above the light source, and the mounting seats can be positioned on two opposite side edges in the cascade grating and used for mounting the grating to be measured. Therefore, the light emitted by the light source is emitted from the bottom surface of the cascade grating, emitted from the top surface of the cascade grating, emitted from the bottom surface of the grating to be detected and emitted from the top surface of the grating to be detected. The interference pattern formed after light penetrates through the cascade grating and the grating to be detected can be observed through the observation window arranged above the grating to be detected, and the camera arranged above the grating to be detected is adopted to shoot the interference pattern, so that an experimenter can determine the period of the grating to be detected according to the shot interference pattern. The whole device is simple in structure, the period of the grating to be measured can be measured only by using the cascade grating, and the difficulty of use and daily maintenance is greatly reduced.
Drawings
Fig. 1a is a schematic structural diagram of a measurement apparatus for measuring a grating period according to an embodiment of the present disclosure;
FIG. 1b is a cross-sectional view of a grating period measurement device according to an embodiment of the present disclosure;
fig. 2 is a schematic diagram illustrating a positional relationship between a base and a light source according to an embodiment of the present disclosure;
fig. 3 is a top view of a cascaded grating according to an embodiment of the present application;
fig. 4 is a schematic structural diagram of a cascaded grating with scales according to an embodiment of the present disclosure;
FIG. 5 is a schematic illustration of an interference pattern provided by an embodiment of the present application;
fig. 6 is a schematic view illustrating an observation window and a camera mounted through a cross beam according to an embodiment of the present disclosure;
FIG. 7 is a schematic structural diagram of a measurement apparatus for measuring an adjustable grating period according to an embodiment of the present disclosure;
fig. 8 is a schematic diagram illustrating a position of a polarizer in a periodic measurement apparatus for a phase grating according to an embodiment of the present disclosure;
fig. 9 is a schematic flowchart of a method for measuring a grating period according to an embodiment of the present application.
Detailed Description
To make the objects, technical solutions and advantages of the present application more clear, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.
Example one
Fig. 1a schematically shows a structural diagram of a measurement apparatus of a grating period provided in an embodiment of the present application. As shown in fig. 1a, the apparatus 100 may include a base 101, a light source 102, a cascade grating 103, a mount 104, an observation window 105, and a camera 106.
Wherein the light source 102 may be located on the base 101. Specifically, the position relationship between the light source 102 and the base 101 can be various, and in one example, as shown in fig. 1a, the base 101 can be a hollow structure, and then the light source 102 can be located in the hollow structure of the base 101 (the light source 102 is not shown in fig. 1a due to the shielding of the base 101). Further, the outer wall dimensions of the light source 102 may match the hollow inner wall dimensions of the base 101.
Fig. 1b is a cross-sectional view of a grating period measuring device according to an embodiment of the present application. It is clear from fig. 1b that the light source 102 may be located in the base 101.
Note that the observation window 105 and the camera 106 are not shown in fig. 1 b.
In another example, as shown in fig. 2, a schematic diagram of a positional relationship between a base and a light source is provided in an embodiment of the present application. The light source 102 may be located on the top surface of the base 101. Further, the bottom surface of the light source 102 may be sized to match the top surface of the base 101.
In other possible examples, the light source 102 and the base 101 may have other positional relationships, which can be determined by those skilled in the art based on experience or practical situations, and are not limited in particular.
Further, the light source 102 may be various types of light sources, such as an LED light source, without limitation.
In the embodiment of the present application, the cascade grating 103 may be installed above the light source 102, so that the light emitted from the light source 102 can enter from the bottom surface of the cascade grating 103 and exit from the top surface of the cascade grating 103.
The cascade grating 103 is formed by cascading a plurality of sector gratings. Fig. 3 is a top view of a cascaded grating according to an embodiment of the present invention. The cascade grating 103 may include four fan-shaped gratings 1031, and the side surfaces of any two adjacent fan-shaped gratings 1031 are cascaded together to form the cascade grating 103. Wherein the minimum period of the fan-shaped grating 1031 is Λ1Maximum period of Λ2。
Further, the size of the bottom surface of the cascade grating 103 may be matched to the size of the light emitting surface of the light source 102, so that any position of the cascade grating 103 may be illuminated by the light source.
As can be seen from fig. 1a, the mounting seats 104 may be located on two opposite sides of the cascaded grating 103, i.e. the first side and the second side shown in fig. 1a, which may be longer sides of the cascaded grating 103.
The mounting block 104 may be used to mount the grating 107 to be tested. After the grating 107 to be measured is installed, the grating 107 to be measured may be located above the cascade grating 103, so that the light emitted from the light source 102 may be emitted from the top surface of the cascade grating 103, then emitted from the bottom surface of the grating 107 to be measured, and emitted from the top surface of the grating 107 to be measured.
Further, the size of the bottom surface of the grating 107 to be measured may be smaller than or equal to the size of the bottom surface of the cascade grating 103.
As shown in fig. 1a, the observation window 105 may be installed above the grating 107 to be measured, and is used for observing the interference pattern formed after the light passes through the cascade grating 103 and the grating 107 to be measured.
Wherein the interference pattern may be moire fringes. Moir is the visual result of interference between two wires or two objects at a constant angle and frequency. The scientific meaning of moire refers to the difference or beat frequency pattern that results when two periodic structure patterns overlap. When the human eye cannot distinguish the two lines or objects, only the interference pattern is visible, and the pattern in this optical phenomenon is the moire fringes.
Specifically, when the grating to be detected is overlapped with the cascade grating, moire fringes can be generated, and the moire fringes have the rule that the closer the period between the grating to be detected and the cascade grating is, the larger the period of the moire fringes is; the larger the period difference between the grating to be detected and the cascade grating is, the smaller the period of the Moire fringe is.
Further, the experimenter may determine the period of the grating 107 to be measured according to the captured interference pattern (e.g., moire fringes). In order to increase the speed of determining the grating period by an experimenter, as shown in fig. 4, a scale value is set on the cascade grating 103, and the scale value may be a numerical value corresponding to the center of the moire fringe, for a structural schematic diagram of the cascade grating with scale provided in the embodiment of the present application. Therefore, when in measurement, the grating to be measured is horizontally placed above the grating ruler to form moire fringes as shown in fig. 5, and the scales corresponding to the centers of the moire fringes can be directly read through the graph 5.
The camera 106 may also be installed above the grating 107 to be measured, and is configured to capture the interference pattern, so that an experimenter can determine the period of the grating 107 to be measured according to the captured interference pattern. Furthermore, the camera 106 may be installed near the observation window 105, and at the same time, the camera 106 may be located at the same height as the observation window 105, so that the interference pattern photographed by the camera 106 is consistent with the interference pattern observed by the experimenter from the observation window 105.
It should be noted that the structure of the measurement apparatus for measuring the grating period described in fig. 1a can be applied to the case where the grating 107 to be measured is an intensity grating, and if the grating 107 to be measured is a phase grating, the measurement apparatus described in the second embodiment below can be used to perform the measurement.
By adopting the grating period measuring device provided by the embodiment of the application, the cascade grating can be arranged above the light source, and the mounting seats can be positioned on two opposite side edges in the cascade grating and used for mounting the grating to be measured. Therefore, the light emitted by the light source is emitted from the bottom surface of the cascade grating, emitted from the top surface of the cascade grating, emitted from the bottom surface of the grating to be detected and emitted from the top surface of the grating to be detected. The interference pattern formed after light penetrates through the cascade grating and the grating to be detected can be observed through the observation window arranged above the grating to be detected, and the camera arranged above the grating to be detected is adopted to shoot the interference pattern, so that an experimenter can determine the period of the grating to be detected according to the shot interference pattern. The whole device is simple in structure, the period of the grating to be measured can be measured only by using the cascade grating, and the difficulty of use and daily maintenance is greatly reduced.
In the embodiment of the present application, there are various installation manners of the observation window 105 and the camera 106, and the observation window and the camera may be installed above the grating 107 to be measured in a suspension manner. The application provides a mode of mounting through a cross beam, and an observation window 105 and a camera 106 are mounted. As shown in fig. 6, a schematic diagram of an observation window and a camera mounted through a cross beam is provided for the embodiment of the present application.
As can be seen in fig. 6, the apparatus 100 may further include a first upright 110, a second upright 111, and a cross-member 112. One end of the first upright 110 may be fixedly connected to the first side surface 1011 of the base 101, and the other end may be connected to one end of the cross beam 112; one end of the second upright 111 may be fixedly connected to the second side 1012 of the base 101, and the other end may be connected to the other end of the cross beam 112. The first side 1011 and the second side 1012 are two opposing sides.
Further, the heights of the first vertical column 110 and the second vertical column 111 may be both higher than the position of the top surface of the grating 107 to be measured.
Further, the observation window 105 and the camera 106 may be mounted on the beam 112, respectively. By adopting the method, the structure is simple, the installation is convenient, and the installation stability of the observation window 105 and the camera 106 is higher.
In consideration of the fact that when the grating period is measured, it is usually necessary for an experimenter to repeatedly adjust the observation position to obtain a satisfactory interference pattern, that is, it is necessary to adjust the position and height of the observation window 105, or adjust the position and height of the camera 106, or adjust the position of the grating 107 to be measured, so as to observe a better interference pattern.
Fig. 7 schematically shows a structural diagram of a measurement apparatus for measuring an adjustable grating period provided by an embodiment of the present application. As shown in fig. 7, the apparatus 100 may further include a slider 113, and the slider 113 may be nested on the beam 112 and may move along the length direction of the beam 112.
The observation window 105 can be connected with the sliding block 113, is arranged on the cross beam 112 through the sliding block 113, and moves along the length direction of the cross beam 112 under the driving of the sliding block 113; the camera 106 may also be connected to the slider 113, and is mounted on the beam 112 through the slider 113, and is driven by the slider 113 to move along the length direction of the beam 112.
By adopting the structure, the slide block 113 can drive the observation window 105 and the camera 106 to move in the horizontal direction, so that the horizontal positions of the observation window 105 and the camera 106 can be adjusted.
Further, the device 100 may also include a first connector 114 and a second connector 115.
One end of the first upright 110 may be fixedly connected to the first side surface 1011 of the base 101, and the other end may be connected to one end of the cross beam 112 through the first connecting member 114; one end of the second upright 111 may be fixedly connected to the second side 1012 of the base 101, and the other end may be connected to the other end of the cross beam 112 through the second connector 115.
In this manner, the height of the cross member 112 can be adjusted by adjusting the connecting position of the first connecting member 114 to the cross member 112 and adjusting the connecting position of the second connecting member 115 to the cross member 112.
With this structure, the height of the cross beam 112, and thus the height of the observation window 105 and the camera 106, can be adjusted by the first connection member 114 and the second connection member 115.
Further, the mounting base 104 may be a guide rail, and the grating 107 to be measured may move along the guide rail 116.
By adopting the structure, the grating 107 to be measured can be driven to move in the horizontal direction through the guide rail, so that the horizontal position of the grating 107 to be measured can be adjusted.
Example two
If the grating 107 to be measured is a phase grating, the phase grating can be converted into an intensity grating, so that the period of the phase grating can be measured. The whole structure can refer to the structure of the grating period measuring device provided in fig. 7, and unlike fig. 7, it is necessary to convert the phase grating into the intensity grating by means of orthogonal polarization, that is, two polarizing plates are added in fig. 7 from the structural point of view.
In order to describe the position of the polarizer more clearly, the period measuring apparatus of the phase grating will be described below with reference to fig. 7 and 8. Fig. 8 is a schematic diagram illustrating a position of a polarizer in a periodic measurement apparatus for a phase grating according to an embodiment of the present disclosure.
As can be seen in fig. 8, the light source 102 may be located on the base 101. The positional relationship between the light source 102 and the base 101 can refer to the description of the embodiment, and is not described herein again.
The cascade grating 103 may be mounted above the light source 102 such that light emitted from the light source 102 is incident from a bottom surface of the cascade grating 103 and emitted from a top surface of the cascade grating 103. The cascade grating 103 is formed by cascading a plurality of sector gratings, and the specific structure of the cascade grating 103 may refer to the content described in fig. 3 in the embodiment, which is not described herein again.
The first polarizer 108 may be located below the cascade grating 103, such that the light emitted from the light source 102 enters from the bottom surface of the first polarizer 108 and exits from the top surface of the first polarizer 108 to enter the cascade grating 103.
The mounting seats 104 may be located on two opposite sides of the cascaded grating 103, i.e. the first side and the second side shown in fig. 1a, which may be the longer sides of the cascaded grating 103.
The mounting block 104 may be used to mount the grating 107 to be tested. After the grating 107 to be measured is installed, the grating 107 to be measured may be located above the cascade grating 103, so that the light emitted from the light source 102 may be emitted from the top surface of the cascade grating 103, then emitted from the bottom surface of the grating 107 to be measured, and emitted from the top surface of the grating 107 to be measured.
The second polarizer 109 may be located below the grating 107 to be measured, and the light emitted from the light source 102 may be emitted from the top surface of the cascade grating 103, then enter from the bottom surface of the second polarizer 109, then exit from the top surface of the second polarizer 109, then enter from the bottom surface of the grating 107 to be measured, and finally exit from the top surface of the grating 107 to be measured.
For other structures in the period measuring device of the phase grating, reference may be made to the description in fig. 7, which is not repeated herein.
By adopting the phase grating period measuring device provided by the embodiment of the application, the two-phase grating can be converted into the intensity grating through the first polaroid and the second polaroid, the whole device is simple in structure, the period of the grating to be measured can be measured only by using the cascade grating, and the difficulty of use and daily maintenance is greatly reduced.
EXAMPLE III
Based on the same inventive concept, the present application further provides a method for measuring a grating period, which can be applied to the apparatus 100 for measuring a grating period described in the first embodiment (or the second embodiment). As shown in fig. 9, a schematic flow chart of a method for measuring a grating period is further provided in the embodiment of the present application, which specifically includes the following steps:
step 901, mounting the grating 107 to be tested on the mounting base 104.
Step 902, turn on the light source 102.
Step 903, observing an interference pattern formed after light penetrates through the cascade grating 103 and the grating to be detected 107 through the observation window 105.
In the process of performing step 903, the position of the first connecting element 114 and the second connecting element 115 can be adjusted by moving the sliding block 113, and the grating 107 to be measured is moved, so that a better interference pattern can be observed from the observation window 105.
And 904, shooting the interference pattern by using the camera 106, and determining the period of the grating 107 to be measured according to the shot interference pattern.
Further, if the cascade grating 103 has scale values, experimenters can intuitively and quickly read out the scales corresponding to the centers of the moire fringes, so that the measurement speed of the grating period is accelerated.
By adopting the grating period measuring device provided by the embodiment of the application, the cascade grating can be arranged above the light source, and the mounting seats can be positioned on two opposite side edges in the cascade grating and used for mounting the grating to be measured. Therefore, the light emitted by the light source is emitted from the bottom surface of the cascade grating, emitted from the top surface of the cascade grating, emitted from the bottom surface of the grating to be detected and emitted from the top surface of the grating to be detected. The interference pattern formed after light penetrates through the cascade grating and the grating to be detected can be observed through the observation window arranged above the grating to be detected, and the camera arranged above the grating to be detected is adopted to shoot the interference pattern, so that an experimenter can determine the period of the grating to be detected according to the shot interference pattern. When the device is used for grating measurement, the method is simple and convenient to measure, and the step of measuring the grating period by experimenters is greatly simplified.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any variations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.
It will be understood that the present disclosure is not limited to the precise arrangements described above and shown in the drawings and that various modifications and changes may be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.
Claims (10)
1. A device for measuring the period of a grating, characterized in that the device (100) comprises a base (101) and a light source (102) located on the base (101); the device (100) further comprises a cascade grating (103), a mounting seat (104), an observation window (105) and a camera (106);
the cascade grating (103) is arranged above the light source (102), and light rays emitted by the light source (102) are emitted from the bottom surface of the cascade grating (103) and emitted from the top surface of the cascade grating (103); the cascade grating (103) is formed by cascading a plurality of fan-shaped gratings; wherein the minimum period of the fan-shaped grating is' Lambda1", the maximum period is" "A2"；
The mounting seats (104) are positioned on two opposite side edges in the cascade grating (103) and used for mounting a grating (107) to be tested; the grating (107) to be tested is arranged above the cascade grating (103) after being installed, and light rays emitted by the light source (102) are emitted from the top surface of the cascade grating (103), then emitted from the bottom surface of the grating (107) to be tested and emitted from the top surface of the grating (107) to be tested;
the observation window (105) is arranged above the grating (107) to be measured and is used for observing an interference pattern formed after light penetrates through the cascade grating (103) and the grating (107) to be measured;
the camera (106) is installed above the grating (107) to be measured, is close to the observation window (105), is located at the same height with the observation window (105), and is used for shooting the interference pattern, so that an experimenter can determine the period of the grating (107) to be measured according to the shot interference pattern.
2. The device of claim 1, wherein the interference pattern is a moire pattern;
the cascade grating (103) is provided with scale values, and the scale values are numerical values corresponding to the centers of the moire fringes.
3. The device according to claim 1, wherein when the grating under test (107) is a phase grating under test, the device (100) further comprises a first polarizer (108) and a second polarizer (109);
the first polarizer (108) is positioned below the cascade grating (103), and light emitted by the light source 102 is incident from the bottom surface of the first polarizer (108) and is incident into the cascade grating (103) after being emitted from the top surface of the first polarizer (108);
the second polaroid (109) is located below the grating (107) to be tested, and light emitted by the light source (102) is emitted from the top surface of the cascade grating (103), then is emitted from the bottom surface of the second polaroid (109), is emitted from the top surface of the second polaroid (109), is emitted from the bottom surface of the grating (107) to be tested, and is emitted from the top surface of the grating (107) to be tested.
4. The device according to claim 1, wherein the device (100) further comprises a first upright column (110), a second upright column (111) and a cross beam (112), wherein the heights of the first upright column (110) and the second upright column (111) are higher than the position of the top surface of the grating (107) to be measured;
one end of the first upright post (110) is fixedly connected with the first side surface of the base (101), and the other end of the first upright post is connected with one end of the cross beam (112);
one end of the second upright post (111) is fixedly connected with a second side surface of the base (101) opposite to the first side surface, and the other end of the second upright post is connected with the other end of the cross beam (112);
the observation window (105) and the camera (106) are respectively arranged on the cross beam (112).
5. The device according to claim 4, wherein the device (100) further comprises a slider (113);
the sliding block (113) is nested on the cross beam (112) and moves along the length direction of the cross beam (112);
the observation window (105) is connected with the sliding block (113), is arranged on the cross beam (112) through the sliding block (113), and is driven by the sliding block (113) to move along the length direction of the cross beam (112);
the camera (106) is connected with the sliding block (113), is arranged on the cross beam (112) through the sliding block (113), and moves along the length direction of the cross beam (112) under the driving of the sliding block (113).
6. The device according to claim 4, wherein the device (100) further comprises a first connector (114) and a second connector (115);
the other end of the first upright post (110) is connected with one end of the cross beam (112) through the first connecting piece (114), and the other end of the second upright post (111) is connected with the other end of the cross beam (112) through the second connecting piece (115);
the height of the cross beam (112) is adjusted by adjusting the connecting position of the first connecting piece (114) and the cross beam (112) and the connecting position of the second connecting piece (115) and the cross beam (112).
7. The device according to claim 1, characterized in that said base (101) is a hollow structure;
the light source (102) is located in a hollow structure of the base (101).
8. The device according to claim 1, wherein the size of the bottom surface of the cascade grating (103) matches the size of the light emitting surface of the light source (102);
the size of the bottom surface of the grating (107) to be detected is smaller than or equal to the size of the bottom surface of the cascade grating (103).
9. The device of claim 1, wherein the mounting base (104) is a rail;
the grating (107) to be measured moves along the guide rail.
10. A method for measuring a grating period, characterized in that the method is applied to a device (100) for measuring a grating period according to any one of the preceding claims 1 to 9; the method comprises the following steps:
installing a grating (107) to be tested on an installation seat (104);
turning on a light source (102);
observing an interference pattern formed after light penetrates through the cascade grating (103) and the grating (107) to be detected through an observation window 105;
and shooting the interference pattern by using a camera (106), and determining the period of the grating (107) to be measured according to the shot interference pattern.
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| CN201911169297.3A CN110907140B (en) | 2019-11-25 | Grating period measuring device and method |
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| CN201911169297.3A CN110907140B (en) | 2019-11-25 | Grating period measuring device and method |
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| CN110907140A true CN110907140A (en) | 2020-03-24 |
| CN110907140B CN110907140B (en) | 2024-10-29 |
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| CN115808197A (en) * | 2023-02-06 | 2023-03-17 | 长春长光启衡传感技术有限公司 | Grating inspection device |
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| CN103630077A (en) * | 2013-12-12 | 2014-03-12 | 哈尔滨工业大学 | Two-axis grating displacement measurement system adopting double-frequency laser |
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| JP2004069702A (en) * | 2002-08-07 | 2004-03-04 | Dr Johannes Heidenhain Gmbh | Interference type position-measuring instrument |
| US20070183581A1 (en) * | 2006-02-01 | 2007-08-09 | Bjorn Heismann | Focus/detector system of an X-ray apparatus for generating phase contrast recordings |
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