CN110763135A - High-precision laser interferometer - Google Patents
High-precision laser interferometer Download PDFInfo
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- CN110763135A CN110763135A CN201911011147.XA CN201911011147A CN110763135A CN 110763135 A CN110763135 A CN 110763135A CN 201911011147 A CN201911011147 A CN 201911011147A CN 110763135 A CN110763135 A CN 110763135A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B9/00—Measuring instruments characterised by the use of optical techniques
- G01B9/02—Interferometers
- G01B9/02055—Reduction or prevention of errors; Testing; Calibration
- G01B9/02075—Reduction or prevention of errors; Testing; Calibration of particular errors
- G01B9/02076—Caused by motion
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Abstract
The invention relates to a high-precision laser interferometer which comprises a reading head, a first fixed right-angle reflecting mirror group and a second fixed right-angle reflecting mirror group, wherein the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group are respectively arranged on two sides of the reading head, the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group are arranged in a mirror symmetry mode, and the reading head comprises a laser source, a spectroscope, a reflecting mirror, a movable right-angle reflecting mirror group, a condensing lens and a photoelectric detector. Two paths of laser beams, namely the reflected laser and the transmitted laser, are interfered after being incident to a photoelectric detector through a condensing lens, and the photoelectric detector detects the interference phenomenon to obtain the relative displacement of the reading head to the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group; when the reading head moves, the interference laser realizes a difference effect, when the optical path of one laser in the two paths of interference laser is reduced, the optical path of the other laser is inevitably increased, and the amplification factor of the optical path difference of the interference laser is improved, so that the interference displacement measurement precision of the laser interferometer is improved.
Description
Technical Field
The invention relates to the technical field of measurement precision, in particular to a high-precision laser interferometer.
Background
The laser interferometer uses the laser wavelength as the known length and utilizes the Michelson interference system to measure the general length measurement of the displacement. According to the principle of laser interference, the displacement measurement precision of a classic michelson laser interferometer is half of the laser wavelength. The interferometer is required to be improved in principle for higher-precision measurement precision so as to realize higher-precision displacement measurement, and meanwhile, the existing laser interferometer is often used for machine tool detection and other works and is difficult to realize online application of equipment such as a machine tool, and new requirements are provided for the structure of the laser interferometer.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a high-precision laser interferometer for accurately measuring the precision.
In order to achieve the above object, the embodiments of the present invention provide the following technical solutions:
a high precision laser interferometer comprising: the reading head, a first fixed right-angle reflector group and a second fixed right-angle reflector group are respectively arranged on two sides of the reading head, and the first fixed right-angle reflector group and the second fixed right-angle reflector group are arranged in a mirror symmetry mode;
the reading head comprises:
a laser source for emitting a laser beam;
the spectroscope is used for receiving the laser beam emitted by the laser source, reflecting/transmitting the received laser beam to the reflecting mirror and transmitting/reflecting the received laser beam to the moving right-angle reflecting mirror group;
the reflecting mirror is used for receiving the laser beams reflected/transmitted by the spectroscope and reflecting the received laser beams to the movable right-angle reflecting mirror group;
the movable right-angle reflecting mirror group is arranged between the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, is used for receiving the laser beams reflected by the reflecting mirrors and the laser beams transmitted by the spectroscopes, respectively reflects the laser beams reflected by the reflecting mirrors and the laser beams transmitted by the spectroscopes to the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, and finally reflects the two laser beams to the condensing lens after multiple reflections between the first fixed right-angle reflecting mirror group, the second fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group;
the condensing lens is used for receiving the two laser beams reflected by the movable right-angle reflecting mirror group and transmitting the two laser beams to the photoelectric detector;
and the photoelectric detector is arranged at the focal position of the condensing lens and used for receiving the laser beam transmitted by the condensing lens.
The spectroscope receives a laser beam emitted by the laser source, the spectroscope divides the laser beam into a reflection laser and a transmission laser, the reflection laser is shot into the movable right-angle reflecting mirror group through the reflecting mirror, the transmission laser is directly shot into the movable right-angle reflecting mirror group, the reflection laser is shot into the condensing lens after being reflected for multiple times between the first fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group, the transmission laser is shot into the condensing lens after being reflected for multiple times between the second fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group, the two paths of laser beams of the reflection laser and the transmission laser are shot into the photoelectric detector through the condensing lens and then interfere with each other, and the photoelectric detector detects the interference phenomenon to obtain the relative displacement of the reading head to the first fixed right.
Or, the spectroscope receives the laser beam emitted by the laser source, the spectroscope divides the laser beam into reflected laser and transmitted laser, the transmitted laser is shot into the movable right-angle reflecting mirror group through the reflecting mirror, the reflected laser is shot into the movable right-angle reflecting mirror group directly, the transmitted laser is shot into the condensing lens after being reflected for multiple times between the first fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group, the reflected laser is shot into the condensing lens after being reflected for multiple times between the second fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group, the two paths of laser beams of the reflected laser and the transmitted laser are shot into the photoelectric detector through the condensing lens and then interfere with each other, and the photoelectric detector detects the interference phenomenon to obtain the relative displacement of the reading head to the first fixed right-angle.
Furthermore, in order to better implement the present invention, the reading head is connected to a moving device for driving the reading head to move in parallel towards the first fixed right-angle reflector set or towards the second fixed right-angle reflector set. The first fixed right-angle reflector group is fixed relative to the second fixed right-angle reflector group, and when the moving device drives the reading head to move towards the first fixed right-angle reflector group, the distance between the reading head and the first fixed right-angle reflector group is reduced, and the distance between the reading head and the second fixed right-angle reflector group is increased; when the moving device drives the reading head to move towards the second fixed right-angle reflecting mirror group, the distance between the reading head and the second fixed right-angle reflecting mirror group is reduced, and the distance between the reading head and the first fixed right-angle reflecting mirror group is increased.
Further, in order to better implement the present invention, the photodetector is connected with a processor for detecting an interference phenomenon on the photodetector. When the moving device drives the reading head to move, the interference laser realizes a difference effect, when the optical path of one laser beam in the two paths of interference laser is reduced, the optical path of the other laser beam is inevitably increased, and the amplification factor of the optical path difference of the interference laser is improved. Meanwhile, the fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group are folded for multiple times, so that the multiple of the optical path difference is further improved, and the measurement precision of the laser interferometer is finally improved.
Furthermore, in order to better implement the present invention, the high-precision laser interferometer is disposed in the housing, the first fixed rectangular mirror group and the second fixed rectangular mirror group are fixedly disposed in the housing, and the moving device is slidably disposed in the housing, so that the moving device can drive the reading head to move in the direction of the first fixed rectangular mirror group and the second fixed rectangular mirror group.
Furthermore, in order to better implement the present invention, the beam splitter and the laser beam emitted by the laser source form an included angle of 45 °, and the reflecting mirror and the beam splitter are arranged in parallel.
Furthermore, in order to better implement the present invention, each of the first fixed rectangular mirror group and the second fixed rectangular mirror group includes N fixed rectangular reflecting surfaces.
Further, in order to better implement the present invention, the moving rectangular mirror group includes 2N rectangular reflecting surfaces.
Furthermore, in order to better implement the present invention, the N fixed rectangular reflecting surfaces of the first fixed rectangular mirror group and the front/rear N rectangular reflecting surfaces of the moving rectangular mirror group are arranged in parallel in a one-to-one correspondence, and the N fixed rectangular reflecting surfaces of the second fixed rectangular mirror group and the rear/front N rectangular reflecting surfaces of the moving rectangular mirror group are arranged in parallel in a one-to-one correspondence.
Further, the condensing lens may be a condensing mirror.
As another possible embodiment, a high-precision laser interferometer includes:
the reading head, the moving mirror group, the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group;
the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group are respectively arranged at two sides of the movable mirror group, and the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group are in mirror symmetry;
the mobile lens group comprises:
the spectroscope is used for receiving the laser beam emitted by the laser source, transmitting the received laser beam to the first reflector and reflecting the received laser beam to the movable right-angle reflector group;
the first reflector is used for receiving the laser beam transmitted by the spectroscope and reflecting the received laser beam to the movable right-angle reflector group;
the movable right-angle reflecting mirror group is arranged between the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group and is used for receiving the laser beams reflected by the first reflecting mirror and the laser beams reflected by the spectroscope, respectively reflecting the laser beams reflected by the first reflecting mirror and the laser beams reflected by the spectroscope to the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, and finally reflecting the two laser beams to the second reflecting mirror after multiple reflections between the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group and between the movable right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group;
the second reflector is used for receiving the laser beams reflected by the movable right-angle reflector group and reflecting the received laser beams to the condensing lens;
the reading head comprises:
a laser source for emitting a laser beam;
the condensing lens is used for receiving the two laser beams reflected by the second reflector and transmitting the two laser beams to the photoelectric detector;
and the photoelectric detector is arranged at the focal position of the condensing lens and used for receiving the laser beam transmitted by the condensing lens.
The laser source, the condensing lens and the photoelectric detector are fixedly arranged relative to the fixed right-angle reflecting mirror group, when the movable mirror group moves, the condensing lens or the photoelectric detector cannot generate a tiny angle error any more, so that the interference phenomenon generated on the photoelectric detector is more accurate, and the measurement precision in the actual measurement process is further improved.
Furthermore, in order to better implement the present invention, the movable mirror group is connected to a moving device for driving the movable mirror group to move in parallel towards the first fixed right-angle mirror group or towards the second fixed right-angle mirror group.
Compared with the prior art, the invention has the beneficial effects that:
the two laser beams of the reflected laser and the transmitted laser are interfered after being incident to the photoelectric detector through the condensing lens, and the photoelectric detector detects the interference phenomenon to obtain the relative displacement of the reading head to the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group. Because the laser beams are reflected for multiple times between the movable right-angle reflecting mirror group and the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, the optical path difference of the two laser beams is also amplified; meanwhile, when the reading head moves, the interference laser realizes a difference effect, when the optical path of one laser in the two paths of interference laser is reduced, the optical path of the other laser is inevitably increased, so that the amplification factor of the optical path difference of the interference laser is further improved, and the interference displacement measurement precision of the laser interferometer is improved.
According to the invention, the laser source, the reflecting mirror, the spectroscope, the moving right-angle reflecting mirror group, the condensing lens and the photoelectric detector are arranged in the reading head, so that the mutual position relation among the optical devices is fixed, and the two fixed right-angle reflecting mirror groups are still parallel to the incident laser when reflecting the incident laser, so that when the reading head moves, the interference measurement cannot be influenced by the existing tiny angle error, and the measurement precision in the actual measurement process is also improved. More importantly, through further improvement, in the measuring process, the laser source and the photoelectric detector do not move any more, so that the related cables do not participate in moving, and the method is beneficial to practical engineering application.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.
FIG. 1 is a schematic structural diagram of a laser interferometer in embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of another laser interferometer according to embodiment 1 of the present invention;
FIG. 3 is a schematic diagram of a reading head after moving according to embodiment 1 of the present invention;
FIG. 4 is a schematic view of a mobile rectangular mirror assembly according to the present invention;
FIG. 5(a) is a schematic view of a first fixed rectangular mirror assembly according to the present invention;
FIG. 5(b) is a schematic structural view of a second fixed rectangular mirror assembly according to the present invention;
FIG. 6 is a schematic diagram of the displacement of the reading head after moving;
fig. 7 is a schematic structural diagram of a laser interferometer in embodiment 2 of the present invention.
Description of the main elements
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures. Also, in the description of the present invention, the terms "first", "second", and the like are used for distinguishing between descriptions and not necessarily for describing a relative importance or implying any actual relationship or order between such entities or operations.
Example 1:
the invention is realized by the following technical scheme that as shown in fig. 1, the high-precision laser interferometer comprises a reading head 1, and a first fixed rectangular reflector set 201 and a second fixed rectangular reflector set 202 which are respectively arranged at two sides of the reading head 1, wherein the first fixed rectangular reflector set 201 and the second fixed rectangular reflector set 202 are arranged in a mirror symmetry mode. The reading head 1 comprises a laser source 100, a beam splitter 101, a reflector 102, a moving right-angle reflector group 103, a condenser lens 104 and a photoelectric detector 105. Wherein:
a laser source 100 for emitting a laser beam to the beam splitter 101.
The spectroscope 101 is obliquely arranged at a position where the laser source emits laser beams, forms an included angle of 45 degrees with the laser beams emitted by the laser source 100, and is used for receiving the laser beams emitted by the laser source 100, reflecting the received laser beams to the reflector 102 and transmitting the reflected laser beams to the movable right-angle reflector group 103; to distinguish the two beams, the laser light reflected by the mirror 102 is defined as reflected laser light, and the laser light transmitted by the moving mirror group 103 is defined as transmitted laser light.
The reflecting mirror 102 is disposed parallel to the beam splitter 101, i.e. forms an angle of 45 ° with the laser beam emitted by the laser source 100, and is configured to receive the reflected laser beam emitted by the beam splitter 101 and reflect the received reflected laser beam to the moving right-angle reflecting mirror group 103.
The movable right-angle reflecting mirror group 103 is disposed between the first fixed right-angle reflecting mirror group 201 and the second fixed right-angle reflecting mirror group 202, and is configured to receive the reflected laser light reflected by the reflecting mirror 102 and the transmitted laser light transmitted by the beam splitter 101, and reflect the received reflected laser light and transmitted laser light to the first fixed right-angle reflecting mirror group 201 and the second fixed right-angle reflecting mirror group 202, respectively. After the reflected laser light is reflected for multiple times between the movable right-angle reflecting mirror group 103 and the first fixed right-angle reflecting mirror group 201, the movable right-angle reflecting mirror group 103 reflects the reflected laser light into the condensing lens 104; after the transmission laser light is reflected for multiple times between the movable right-angle mirror group 103 and the second fixed right-angle mirror group 202, the movable right-angle mirror group 103 reflects the transmission laser light into the condenser lens 104.
And the condenser lens 104 is used for receiving the reflected laser light and the transmitted laser light reflected by the moving right-angle reflector group 103 and transmitting the two laser beams onto the photoelectric detector 105.
And a photodetector 105 for receiving the laser beam transmitted by the condensing lens 104.
The reading head 1 is connected with a moving device for driving the reading head 1 to move in parallel towards the first fixed right-angle reflector set 201 or towards the second fixed right-angle reflector set 202. The first fixed right-angle reflector set 201, the movable right-angle reflector set 103 and the second fixed right-angle reflector set 202 are on the same straight line, and when the reading head 1 is driven by the moving device to move towards the first fixed right-angle reflector set 201, the distance between the movable right-angle reflector set 103 and the first fixed right-angle reflector set 201 becomes smaller, and the distance between the movable right-angle reflector set 103 and the second fixed right-angle reflector set 202 becomes larger; when the moving device drives the reading head 1 to move towards the second fixed rectangular mirror set 202, the distance between the moving rectangular mirror set 103 and the second fixed rectangular mirror set 202 becomes smaller, and the distance between the moving rectangular mirror set 103 and the first fixed rectangular mirror set 201 becomes larger. It should be noted that, during each measurement operation, the moving device only drives the reading head 1 to move in one direction towards the first fixed rectangular mirror set 201, or to move in one direction towards the second fixed rectangular mirror set 202.
The photodetector 105 is connected to a processor for detecting an interference phenomenon generated on the photodetector 105.
The high-precision laser interferometer is arranged in a shell, a first fixed right-angle reflector group 201 and a second fixed right-angle reflector group 202 are fixedly arranged on two opposite surfaces in the shell, and a moving device is arranged on the shell in a sliding mode, so that the moving device can drive a reading head 1 to move between the first fixed right-angle reflector group 201 and the second fixed right-angle reflector group 202. It should be noted that, as shown in fig. 3, the optical devices included in the reading head 1, such as the laser source 100, the beam splitter 101, the mirror 102, the moving right-angle mirror group 103, the condensing lens 104, and the photodetector 105, are all fixed to each other, and when the moving device moves the reading head 1, these optical devices all move together.
Furthermore, the first fixed rectangular mirror set 201 and the second fixed rectangular mirror set 202 have the same structure and are arranged on two sides of the movable rectangular mirror set 103 in mirror symmetry. As shown in fig. 5(a) and 5(b), it is assumed that the first fixed rectangular mirror group 201 and the second fixed rectangular mirror group 202 each include four fixed rectangular reflecting surfaces, i.e., a first fixed rectangular reflecting surface 203, a second fixed rectangular reflecting surface 204, a third fixed rectangular reflecting surface 205, and a fourth fixed rectangular reflecting surface 206, and the first fixed rectangular reflecting surface 203 is perpendicular to the second fixed rectangular reflecting surface 204, the second fixed rectangular reflecting surface 204 is perpendicular to the third fixed rectangular reflecting surface 205, and the third fixed rectangular reflecting surface 205 is perpendicular to the fourth fixed rectangular reflecting surface 206.
If the first fixed set of rectangular mirrors 201 and the second fixed set of rectangular mirrors 202 have four fixed rectangular reflecting surfaces, respectively, then there are eight moving rectangular reflecting surfaces in the moving set of rectangular mirrors 103, which are the same as the number of fixed rectangular reflecting surfaces of the first fixed set of rectangular mirrors 201 and the second fixed set of rectangular mirrors 202 added together. As shown in fig. 4, the eight moving rectangular reflecting surfaces of the moving rectangular mirror group 103 are the first moving rectangular reflecting surface 111, the second moving rectangular reflecting surface 112, the third moving rectangular reflecting surface 113, the fourth moving rectangular reflecting surface 114, the fifth moving rectangular reflecting surface 115, the sixth moving rectangular reflecting surface 116, the seventh moving rectangular reflecting surface 117, and the eighth moving rectangular reflecting surface 118, and the first moving rectangular reflecting surface 111, the second moving rectangular reflecting surface 112, the third moving rectangular reflecting surface 113, the fourth moving rectangular reflecting surface 114 are parallel to the first fixed rectangular reflecting surface 203, the second fixed rectangular reflecting surface 204, the third fixed rectangular reflecting surface 205, and the fourth fixed rectangular reflecting surface 206 of the first fixed rectangular mirror group 201; the fifth moving rectangular reflecting surface 115, the sixth moving rectangular reflecting surface 116, the seventh moving rectangular reflecting surface 117, and the eighth moving rectangular reflecting surface 118 are parallel to the first fixed rectangular reflecting surface 203, the second fixed rectangular reflecting surface 204, the third fixed rectangular reflecting surface 205, and the fourth fixed rectangular reflecting surface 206 of the second fixed rectangular reflecting mirror group 202 one by one. In addition, every two adjacent moving rectangular reflecting surfaces in the moving rectangular mirror group 103 are perpendicular to each other.
It should be further noted that, for the convenience of principle analysis and calculation, the beam splitter 101, the reflecting mirror 102, the first moving right-angle reflecting surface 111 of the moving right-angle reflecting mirror group 103, and the first fixed right-angle reflecting surface 203 of the first fixed right-angle reflecting mirror group 201 are all arranged in parallel, and all form an included angle of 45 ° with respect to the laser beam emitted by the laser source 100.
As shown in fig. 1, a laser source 100 emits a laser beam to a beam splitter 101, and the laser beam is divided into a reflected laser and a transmitted laser at the beam splitter 101, wherein the reflected laser enters a reflecting mirror 102 and then enters a first moving rectangular reflecting surface 111 of a moving rectangular mirror group 103 through the reflecting mirror 102. Since the beam splitter 101 forms an angle of 45 ° with the laser beam emitted from the laser source 100, the reflected laser beam reflected by the beam splitter 101 towards the reflector 102 is perpendicular to the laser beam emitted from the laser source 100, and similarly, after the reflected laser beam reaches the first movable right-angle reflecting surface 111, the reflected laser beam is reflected to the first fixed right-angle reflecting surface 203 of the first fixed right-angle reflecting mirror set 201, the first fixed right-angle reflecting surface 203 reflects the reflected laser beam to the second fixed right-angle reflecting surface 204 of the first fixed right-angle reflecting mirror set 201, the second fixed right-angle reflecting surface 204 reflects the reflected laser beam to the second movable right-angle reflecting surface 112 of the movable right-angle reflecting mirror set 103, the second movable right-angle reflecting surface 112 reflects the reflected laser beam to the third movable right-angle reflecting surface 113, the third movable right-angle reflecting surface 113 reflects the reflected laser beam to the third fixed right-angle reflecting surface 205 of the first fixed right-angle reflecting mirror set 201, the third fixed rectangular reflecting surface 205 reflects the reflected laser light to the fourth fixed rectangular reflecting surface 206 of the first fixed rectangular mirror set 201, the fourth fixed rectangular reflecting surface 206 reflects the reflected laser light to the fourth moving rectangular reflecting surface 114 of the moving rectangular mirror set 103, and finally the fourth moving rectangular reflecting surface 114 reflects the reflected laser light to the condenser lens 104. The principle of reflection between the first fixed rectangular mirror set 201 and the movable rectangular mirror set 103 is the same, and the transmitted laser beam enters the fifth movable rectangular mirror surface 115 of the movable rectangular mirror set 103 from the beam splitter 101, and is reflected by the movable rectangular mirror set 103 and the second fixed rectangular mirror set 202, and is finally reflected to the condenser lens 104 from the eighth movable rectangular mirror surface 118 of the movable rectangular mirror set 103.
The condenser lens 104 is a convex lens, and it can be known from the refraction principle of the convex lens that light passing through the convex lens falls on the focus of the convex lens, and the photoelectric detector 105 is arranged on the focus of the condenser lens 104, so that the laser beam passing through the condenser lens 104 finally falls on the photoelectric detector 105.
Further, the condenser lens 104 may also be a condenser reflector, and the photodetector 10 is disposed at a focal point of the condenser reflector.
As can be easily seen from fig. 1, the laser beam between the first fixed set of rectangular mirrors 201 and the moving set of rectangular mirrors 103 is reflected 4 times, and the number of the fixed rectangular reflecting surfaces of the first fixed set of rectangular mirrors 201 is the same, and similarly, the laser beam between the second fixed set of rectangular mirrors 202 and the moving set of rectangular mirrors 103 is also reflected 4 times. As shown in fig. 3, the moving device (not shown in the figure) moves the reading head 1 to move in parallel in the direction of the first fixed rectangular mirror set 201, after moving, the number of reflections of the laser beam between the first fixed rectangular mirror set 201 and the moving rectangular mirror set 103 is unchanged, but the optical path of the laser beam between the first fixed rectangular mirror set 201 and the moving rectangular mirror set 103 is reduced; similarly, the number of reflections of the laser beam between the second fixed set of rectangular mirrors 202 and the moving set of rectangular mirrors 103 is not changed, but the optical path length of the laser beam between the second fixed set of rectangular mirrors 202 and the moving set of rectangular mirrors 103 is increased. It should be noted that, during the movement, the optical path of the laser reflection between the first fixed rectangular reflecting surface 203 and the second fixed rectangular reflecting surface 204 of the first fixed rectangular mirror set 201 does not change, and similarly, the optical path of the laser reflection between the second moving rectangular reflecting surface 112 and the third moving rectangular reflecting surface 113 of the moving rectangular mirror set 103 does not change.
As shown in fig. 6, it is assumed that the displacement of the reading head 1 driven by the moving device to the direction of the first fixed rectangular mirror set 201 is X, that is, the moving rectangular mirror set 103 has also moved X to the direction of the first fixed rectangular mirror set 201, in other words, the optical path of the reflected laser between the first fixed rectangular mirror set 201 and the moving rectangular mirror set 103 has decreased by 4X, then the optical path of the transmitted laser between the second fixed rectangular mirror set 202 and the moving rectangular mirror set 103 has increased by 4X, and the variation of the optical path difference between the transmitted laser and the reflected laser at this time is 8X.
In this embodiment, the number of the fixed rectangular reflecting surfaces of the first fixed rectangular mirror group 201 and the second fixed rectangular mirror group 202 is not limited, but should be an even number of fixed rectangular reflecting surfaces, and if the first fixed rectangular mirror group 201 and the second fixed rectangular mirror group 202 respectively include N fixed rectangular reflecting surfaces, the moving rectangular mirror group 103 should include at least 2N moving rectangular reflecting surfaces; when the moving device drives the reading head 1 to move toward the first fixed rectangular mirror set 201 or the second fixed rectangular mirror set 202 by a displacement amount X, the optical path difference between the transmitted laser and the reflected laser is 2 NX.
According to the light interference phenomenon, when the interference is long, the optical path difference of the two beams of light is an integral multiple of the laser wavelength, the two laser beams, the reflected laser beam and the transmitted laser beam, are incident on the photoelectric detector 105 through the condenser lens 104 and interfere with each other, and the photoelectric detector 105 detects the interference phenomenon, so that the relative displacement of the reading head 1 to the first fixed right-angle reflector set 201 and the second fixed right-angle reflector set 202 can be obtained. Since the laser beams are reflected for many times between the movable right-angle reflecting mirror group 103 and the first and second fixed right-angle reflecting mirror groups 201 and 202, the optical path difference between the two laser beams is also amplified; meanwhile, when the reading head 1 moves, the interference laser realizes a difference effect, when the optical path of one laser beam in the two interference laser beams is reduced, the optical path of the other laser beam is inevitably increased, so that the amplification factor of the optical path difference of the interference laser beams is further improved, and the interference displacement measurement precision of the laser interferometer is improved.
Implementation 2:
as another possible implementation manner, as shown in fig. 2, the laser source in example 1 is disposed on a side of the beam splitter away from the reflector, and at this time, the laser beam emitted from the laser source to the beam splitter is transmitted to the reflector through the beam splitter and reflected to the movable right-angle reflector set.
Other parts of this embodiment are the same as those of the above embodiment, and thus are not described again.
Example 3:
as another possible implementation, a high-precision laser interferometer, as shown in fig. 7, includes a reading head, a moving mirror group 2, a first fixed rectangular mirror group 201, and a second fixed rectangular mirror group 202, where the reading head includes a laser light source 100, a condensing lens 104, and a photodetector 105. The movable mirror group comprises a beam splitter 101, a first reflecting mirror 106, a second reflecting mirror 107 and a movable right-angle reflecting mirror group 103. The first fixed right-angle mirror group 201 and the second fixed right-angle mirror group 202 are arranged on two sides of the movable right-angle mirror group 103 in a mirror symmetry manner. Wherein:
a laser source 100 for emitting a laser beam to the beam splitter 101.
A beam splitter 101, which is obliquely disposed at a position where the laser source 100 emits a laser beam, forms an included angle of 45 degrees with the laser beam emitted by the laser source 100, and is configured to receive the laser beam emitted by the laser source 100, transmit the received laser beam to the first reflecting mirror 106, and reflect the received laser beam to the moving right-angle reflecting mirror group 103; to facilitate the distinction of the two beams, the laser light transmitted to the first reflecting mirror 106 is defined as transmitted laser light, and the laser light reflected to the moving orthogonal mirror group 103 is defined as reflected laser light.
The first reflecting mirror 106 is disposed parallel to the beam splitter 101, and is configured to receive the transmitted laser light transmitted by the beam splitter 101 and reflect the transmitted laser light to the movable orthogonal mirror group 103.
The movable right-angle mirror group 103 is disposed between the first fixed right-angle mirror group 201 and the second fixed right-angle mirror group 202, and is configured to receive the transmission laser light reflected by the first mirror 106 and the reflection laser light reflected by the beam splitter 101, and reflect the received transmission laser light and reflection laser light to the first fixed right-angle mirror group 201 and the second fixed right-angle mirror group 202, respectively. After the transmission laser is reflected for multiple times between the movable right-angle mirror group 103 and the first fixed right-angle mirror group 201, the movable right-angle mirror group 103 reflects the transmission laser into the second mirror 107; after the reflected laser light undergoes multiple reflections between the moving mirror set 103 and the second fixed mirror set 202, the moving mirror set 103 reflects the reflected laser light to the second mirror 107.
The second reflecting mirror 107 is disposed on a side of the movable rectangular mirror set 103 away from the first reflecting mirror 106, and is parallel to or perpendicular to the first reflecting mirror 106, in this embodiment, the second reflecting mirror 107 is disposed perpendicular to the first reflecting mirror 106, and is configured to receive the transmitted laser light and the reflected laser light reflected by the movable rectangular mirror set 103, and reflect the transmitted laser light and the reflected laser light to the condenser lens 104.
And a condenser lens 104 for receiving the reflected laser light and the transmitted laser light reflected by the second mirror 107 and transmitting the two laser beams onto a photodetector 105.
And a photodetector 105 for receiving the laser beam transmitted by the condensing lens 104. The condenser lens 104 is a convex lens, and it can be known from the refraction principle of the convex lens that light passing through the convex lens falls on the focus of the convex lens, and the photoelectric detector 105 is arranged on the focus of the condenser lens 104, so that the laser beam passing through the condenser lens 104 finally falls on the photoelectric detector 105.
Further, the condenser lens 104 may be a reflective condenser lens.
The photodetector 105 is connected to a processor for detecting an interference phenomenon generated on the photodetector 105.
The movable mirror assembly 2 is connected to a moving device for driving the movable mirror assembly 2 to move towards the first fixed right-angle mirror assembly 201 or the second fixed right-angle mirror assembly 202, the first fixed right-angle mirror assembly 201, the second fixed right-angle mirror assembly 202, and the movable right-angle mirror assembly 103 in this embodiment have the same structure as that in embodiment 1, and the transmission laser is reflected between the first fixed rectangular mirror set 201 and the moving rectangular mirror set 103, and the reflection of the reflected laser light between the second fixed rectangular mirror group 202 and the moving rectangular mirror group 103 are the same as those in embodiment 1, the transmitted laser light is finally reflected from the fourth moving rectangular reflecting surface 114 of the moving rectangular mirror group 103 to the second reflecting mirror 107, and the reflected laser light is finally reflected from the eighth moving rectangular reflecting surface 118 of the moving rectangular mirror group 103 to the second reflecting mirror 107.
During the measurement, the moving device only drives the moving mirror group 2 to move in one direction towards the first fixed rectangular mirror group 201, or to move in one direction towards the second fixed rectangular mirror group 202. When the movable mirror group 2 moves towards the first fixed right-angle mirror group 201, the optical path between the first fixed right-angle mirror group 201 and the movable right-angle mirror group 103 is reduced, that is, the optical path of the transmitted laser light is reduced, and the optical path between the second fixed right-angle mirror group 202 and the movable right-angle mirror group 103 is increased, that is, the optical path of the reflected laser light is increased; the reverse is true.
The high-precision laser interferometer is arranged in a shell, a first fixed right-angle reflector group 201 and a second fixed right-angle reflector group 202 are respectively and fixedly arranged in two opposite directions in the shell, a laser source 100, a condensing lens 104 and a photoelectric detector 105 are also fixedly arranged in the shell, and a moving device is arranged on the shell in a sliding mode, so that the moving device can drive a moving mirror group 2 to move between the first fixed right-angle reflector group 201 and the second fixed right-angle reflector group 202.
It should be noted that, different from embodiment 1, in this embodiment, the movable mirror group 2 is not arranged in the reading head any more, the reading head includes the laser source 100, the condensing lens 104, and the photodetector 105, and when performing measurement, the moving device only drives the movable mirror group 2 to move in parallel, and the reading head composed of the laser source 100, the condensing lens 104, and the photodetector 105 is fixed relative to the housing.
The advantage of the structure of this embodiment over embodiment 1 is that when the movable mirror group 2 moves, a slight angle error may be generated by the condenser lens 104 or the photodetector 105, so that the interference phenomenon generated on the photodetector 105 in embodiment 1 is less accurate than the interference phenomenon generated after the photodetector 105 is fixed in this embodiment, which further improves the measurement accuracy in the actual measurement process. More importantly, in the measuring process, the laser source and the photoelectric detector do not move, so that the cable does not participate in moving, and the practical application is facilitated.
Other parts of this embodiment are the same as those of the above embodiment, and thus are not described again.
The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (10)
1. A high precision laser interferometer, comprising: the method comprises the following steps: the reading head, a first fixed right-angle reflector group and a second fixed right-angle reflector group are respectively arranged on two sides of the reading head, and the first fixed right-angle reflector group and the second fixed right-angle reflector group are arranged in a mirror symmetry mode;
the reading head comprises:
a laser source for emitting a laser beam;
the spectroscope is used for receiving the laser beam emitted by the laser source, reflecting/transmitting the received laser beam to the reflecting mirror and transmitting/reflecting the received laser beam to the moving right-angle reflecting mirror group;
the reflecting mirror is used for receiving the laser beams reflected/transmitted by the spectroscope and reflecting the received laser beams to the movable right-angle reflecting mirror group;
the movable right-angle reflecting mirror group is arranged between the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, is used for receiving the laser beams reflected by the reflecting mirrors and the laser beams transmitted by the spectroscopes, respectively reflects the laser beams reflected by the reflecting mirrors and the laser beams transmitted by the spectroscopes to the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, and finally reflects the two laser beams to the condensing lens after multiple reflections between the first fixed right-angle reflecting mirror group, the second fixed right-angle reflecting mirror group and the movable right-angle reflecting mirror group;
the condensing lens is used for receiving the two laser beams reflected by the movable right-angle reflecting mirror group and transmitting the two laser beams to the photoelectric detector;
and the photoelectric detector is arranged at the focal position of the condensing lens and used for receiving the laser beam transmitted by the condensing lens.
2. A high accuracy laser interferometer according to claim 1 wherein: the reading head is connected with a moving device and used for driving the reading head to move in parallel towards the first fixed right-angle reflector group or the second fixed right-angle reflector group.
3. A high accuracy laser interferometer according to claim 2 wherein: the photoelectric detector is connected with a processor and used for detecting interference phenomena on the photoelectric detector.
4. A high accuracy laser interferometer according to claim 1 wherein: the high-precision laser interferometer is arranged in a shell, a first fixed right-angle reflector group and a second fixed right-angle reflector group are fixedly arranged in the shell, a reading head is arranged in the shell, and the reading head can move towards the first fixed right-angle reflector group and the second fixed right-angle reflector group in the shell.
5. A high accuracy laser interferometer according to claim 1 wherein: the spectroscope is 45 contained angles with the laser beam that the laser source sent, just speculum and spectroscope parallel arrangement.
6. A high accuracy laser interferometer according to claim 1 wherein: the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group respectively comprise N fixed right-angle reflecting surfaces.
7. A high accuracy laser interferometer according to claim 6 wherein: the movable right-angle reflecting mirror group comprises 2N right-angle reflecting surfaces.
8. A high accuracy laser interferometer according to claim 7 wherein: the N fixed right-angle reflecting surfaces of the first fixed right-angle reflecting mirror group and the front/rear N right-angle reflecting surfaces of the movable right-angle reflecting mirror group are arranged in parallel in a one-to-one correspondence mode, and the N fixed right-angle reflecting surfaces of the second fixed right-angle reflecting mirror group and the rear/front N right-angle reflecting surfaces of the movable right-angle reflecting mirror group are arranged in parallel in a one-to-one correspondence mode.
9. A high precision laser interferometer, comprising: the method comprises the following steps:
the reading head, the moving mirror group, the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group;
the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group are respectively arranged at two sides of the movable mirror group, and the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group are in mirror symmetry;
the mobile lens group comprises:
the spectroscope is used for receiving the laser beam emitted by the laser source, transmitting the received laser beam to the first reflector and reflecting the received laser beam to the movable right-angle reflector group;
the first reflector is used for receiving the laser beam transmitted by the spectroscope and reflecting the received laser beam to the movable right-angle reflector group;
the movable right-angle reflecting mirror group is arranged between the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group and is used for receiving the laser beams reflected by the first reflecting mirror and the laser beams reflected by the spectroscope, respectively reflecting the laser beams reflected by the first reflecting mirror and the laser beams reflected by the spectroscope to the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group, and finally reflecting the two laser beams to the second reflecting mirror after multiple reflections between the first fixed right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group and between the movable right-angle reflecting mirror group and the second fixed right-angle reflecting mirror group;
the second reflector is used for receiving the laser beams reflected by the movable right-angle reflector group and reflecting the received laser beams to the condensing lens;
the reading head comprises:
a laser source for emitting a laser beam;
the condensing lens is used for receiving the two laser beams reflected by the second reflector and transmitting the two laser beams to the photoelectric detector;
and the photoelectric detector is arranged at the focal position of the condensing lens and used for receiving the laser beam transmitted by the condensing lens.
10. A high accuracy laser interferometer according to claim 9 wherein: the movable mirror group is connected with a moving device and used for driving the movable mirror group to move in parallel towards the first fixed right-angle reflecting mirror group or towards the second fixed right-angle reflecting mirror group.
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| CN201911011147.XA CN110763135A (en) | 2019-10-23 | 2019-10-23 | High-precision laser interferometer |
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| CN201911011147.XA CN110763135A (en) | 2019-10-23 | 2019-10-23 | High-precision laser interferometer |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108444397A (en) * | 2018-05-18 | 2018-08-24 | 北方民族大学 | New Displacement Transducer and its measurement method |
| CN111537453A (en) * | 2020-04-23 | 2020-08-14 | 山东省科学院激光研究所 | Two-dimensional multi-point reflection long-optical-path gas sensor probe and gas sensor |
-
2019
- 2019-10-23 CN CN201911011147.XA patent/CN110763135A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108444397A (en) * | 2018-05-18 | 2018-08-24 | 北方民族大学 | New Displacement Transducer and its measurement method |
| CN108444397B (en) * | 2018-05-18 | 2024-02-27 | 深邦智能科技集团(青岛)有限公司 | Displacement sensor and measuring method thereof |
| CN111537453A (en) * | 2020-04-23 | 2020-08-14 | 山东省科学院激光研究所 | Two-dimensional multi-point reflection long-optical-path gas sensor probe and gas sensor |
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