CN116678331B - Laser thickness measuring instrument - Google Patents
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- CN116678331B CN116678331B CN202310658197.7A CN202310658197A CN116678331B CN 116678331 B CN116678331 B CN 116678331B CN 202310658197 A CN202310658197 A CN 202310658197A CN 116678331 B CN116678331 B CN 116678331B
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- 238000003384 imaging method Methods 0.000 claims abstract description 66
- 239000000463 material Substances 0.000 claims abstract description 43
- 230000003287 optical effect Effects 0.000 claims description 31
- 230000008859 change Effects 0.000 description 9
- 238000005259 measurement Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000000712 assembly Effects 0.000 description 4
- 238000000429 assembly Methods 0.000 description 4
- 230000007547 defect Effects 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052744 lithium Inorganic materials 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 230000002441 reversible effect Effects 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 238000009683 ultrasonic thickness measurement Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 208000037265 diseases, disorders, signs and symptoms Diseases 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 231100000206 health hazard Toxicity 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 230000035699 permeability Effects 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 238000002834 transmittance Methods 0.000 description 1
Classifications
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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
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
- G01B11/06—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness for measuring thickness ; e.g. of sheet material
Abstract
The invention relates to a laser thickness measuring instrument, which comprises two light path components, an image detector and a thickness calculating device, wherein the light path components comprise a laser and an imaging lens, the laser is positioned at the object plane of the imaging lens, the laser emergent direction of the laser coincides with the thickness direction of a measured material between lasers arranged in the two light path components, the light path components also comprise a reflecting mirror and a pyramid prism, the reflecting mirror is respectively arranged corresponding to the imaging lens and the pyramid prism, the imaging lens is positioned between the laser and the reflecting mirror, the image detector is used for detecting the images of light spots reflected by the two reflecting mirrors, the light spots are formed by converging the laser emitted by the laser to the surface of the measured material, the reflecting mirror reflects the diffuse reflected light rays sequentially, the advancing direction of the diffuse reflected light rays are changed by the imaging lens, and the reflecting mirror reflects the diffuse reflected again, and the thickness calculating device is used for calculating the thickness of the measured material according to the images of the light spots. The laser thickness measuring instrument can eliminate image plane inclination error and resist deformation.
Description
Technical Field
The invention belongs to the technical field of thickness measurement, and particularly relates to a laser thickness measuring instrument.
Background
As materials such as ultrathin plates and films, such as color steel plates, electronic films, conductive glass, pole pieces of new energy lithium batteries and the like, the production and application are very wide, and the requirements on the precision of material processing are higher and higher, the high-precision online thickness measuring technology of the production line is widely applied.
The current common material thickness measuring methods include laser thickness measurement, ray thickness measurement, ultrasonic thickness measurement, eddy current thickness measurement and the like. The thickness measurement of the ray has high cost, and even if the ray is weak, the long-term use still has health hazard to operators, so that radiation diseases are caused; ultrasonic thickness measurement is greatly affected by the surface roughness of the measured object, and is not suitable for thinner measured objects; the eddy current thickness measurement is only suitable for conductive materials, and the detection result is easy to be interfered by the change of conductivity, magnetic permeability and the like of the materials, and the defects limit the online use of the thickness measurement methods. The laser thickness measuring rule is increasingly applied to online thickness measurement by virtue of the advantages of health, environmental protection, no radiation, high precision, simple operation and good instantaneity.
Referring to fig. 1, the existing laser thickness gauge includes an upper laser, a lower laser, an upper imaging lens, a lower imaging lens, an upper mirror, a lower mirror, a A, B set of mirrors, a CCD (Charge-coupled Device) and a processing system, and the working principle of the laser thickness gauge is as follows: the light emitted by the upper laser and the lower laser irradiates the upper surface and the lower surface of a certain point of the measured material respectively, and after being reflected by the upper surface and the lower surface of the measured material, the two laser beams are converged through the upper imaging lens and the lower imaging lens respectively, are reflected through the upper mirror and the lower mirror A, B respectively, and finally are converged on the CCD behind the light path to form two light spots. The processing system acquires the light spot image information of the CCD and processes the picture to obtain the thickness of the measured material.
The laser thickness gauge requires that A1 and B1, A2 and B2 in the A, B two groups of reflectors are symmetrically arranged, but in practice, due to manufacturing errors and installation errors, the inclination angles of the A1 and B1, the A2 and B2 cannot be completely symmetrical, so that the problem that the inclination amounts of the upper image surface and the lower image surface are different and cannot be overlapped exists, namely, upper light spots and lower light spots can be focused at a certain view field point at the same time, and other view fields are separated from the upper image surface and the lower image surface necessarily, so that one of the upper light spots and the lower light spots is dispersed, the inclination error of a measuring result occurs, and the measuring accuracy of the thickness of a measured material is influenced.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention aims to provide a laser thickness measuring instrument which can eliminate the inclination error and deformation resistance of an image plane and improve the measuring precision of the thickness of a measured material.
The technical scheme adopted by the invention is as follows.
The laser thickness measuring instrument comprises two light path components, an image detector and a thickness calculating device, wherein the light path components comprise a laser and an imaging lens, the laser is positioned at the object plane of the imaging lens, the laser emergent direction of the laser coincides with the thickness direction of the measured material between the lasers arranged in the two light path components, the two light path components are symmetrically arranged, the light path components further comprise a reflecting mirror and a pyramid prism,
in the optical path component, the reflecting mirror is respectively arranged corresponding to the imaging lens and the pyramid prism, the imaging lens is positioned between the laser and the reflecting mirror,
the image detectors are respectively arranged corresponding to the reflectors in the two light path components, and are used for detecting the images of light spots reflected by the reflectors in the two light path components, wherein the light spots are formed by converging diffuse reflected light rays sequentially through the imaging lens, reflecting by the reflectors, changing the advancing direction by the pyramid prism and reflecting again by the reflectors after the laser emitted by the laser irradiates the surface of the tested material,
the thickness calculating device is used for calculating the thickness of the measured material according to the images of the light spots reflected by the reflecting mirrors in the two light path components detected by the image detector.
Optionally, the optical axis of the imaging lens is perpendicular to the laser emitting direction and the sensitive surface of the image detector respectively.
Optionally, a large included angle of two reflecting mirrors in the two light path components in the length direction is opposite to the image detector, and the large included angle is larger than 180 °.
Optionally, the surface of the pyramid prism is perpendicular to the light reflected by the mirror.
Optionally, the length direction of the reflecting mirror in the two light path components is equal to the included angle of the laser emergent direction respectively.
Optionally, the imaging lens is a convex lens.
Optionally, the image detector is a charge coupled device.
The invention has the following effects: the laser thickness measuring instrument comprises two light path components, an image detector and a thickness calculating device, wherein the light path components comprise a laser, an imaging lens, a reflecting mirror and a pyramid prism; the laser emergent direction of the laser coincides with the thickness direction of the measured material between the lasers arranged in the two light path components; after laser emitted by the two lasers respectively irradiates the upper surface and the lower surface of the measured material, light diffusely reflected by the upper surface and the lower surface is correspondingly imaged by two groups of imaging lenses which are symmetrically arranged, reflected by the reflecting mirror, changed in advancing direction by the pyramid prism and reflected by the reflecting mirror to form two light spots, the two light spots are detected by the image detector to obtain images of the light spots, and the thickness calculating device calculates the thickness of the measured material according to the images of the light spots; because of the imaging characteristic of the pyramid prism, namely the pyramid prism can change the advancing direction of incident light in parallel, namely, the light reflected to the pyramid prism by the reflecting mirror returns to the reflecting mirror after rotating 180 degrees, which is equivalent to reversely reflecting the light reflected by the reflecting mirror in parallel; the imaging characteristic of the reflector is combined, and the reflected light is reversible, so that the light which is reversely reflected back to the reflector is parallel to the original incident light of the reflector and opposite in direction, namely, the light spots obtained by converging the imaging lens are rotated by 180 degrees through the cooperation of the pyramid prism and the reflector; when the inclination angles of the reflectors in the two light path components are different during installation and adjustment, or the laser thickness measuring instrument deforms during operation, so that the positions and angles of the reflectors and the pyramid prism are slightly changed, as long as the incident light rays and the reflected light rays of the pyramid prism are still within the aperture range of the pyramid prism, the light spots formed by the light paths are rotated 180 degrees, namely the light spots detected by the image detector are unchanged, and therefore the image plane inclination error and deformation resistance are eliminated, and the measuring precision of the thickness of the measured material is improved.
Drawings
Fig. 1 is a schematic structural diagram of a laser thickness gauge according to the background art provided by the invention;
FIG. 2 is a schematic diagram of a laser thickness gauge according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing the deformation resistance of an optical structure of a laser thickness gauge according to an embodiment of the present invention;
fig. 4 is a schematic view of an optical structure of a variation of the laser thickness gauge according to the embodiment of the present invention.
In the figure, 1 light path component, 11 laser, 12 imaging lens, 13 reflector, 14 pyramid prism, 2 image detector, 3 thickness calculation device, 8 measured material.
Detailed Description
The invention is further described below with reference to the drawings and detailed description.
The terms involved in this embodiment are explained as follows.
The object plane refers to the plane where the object imaged by the imaging lens is located.
The image plane refers to a plane where an object is imaged by the imaging lens.
The sensitive surface refers to the sensitive surface of the image detector.
The optical axis refers to a line passing through the center of the imaging lens.
Fig. 2 is a schematic structural diagram of a laser thickness measuring apparatus according to an embodiment of the present invention, referring to fig. 2, the laser thickness measuring apparatus includes two optical path components 1, an image detector 2, and a thickness calculating device 3.
The optical path components 1 include a laser 11 and an imaging lens 12, the laser 11 is located at an object plane of the imaging lens 12, a laser light emitting direction of the laser 11 coincides with a thickness direction of the measured material 8 arranged between the lasers 11 in the two optical path components 1, and the two optical path components 1 are symmetrically arranged.
The light path assembly 1 further comprises a mirror 13 and a corner cube 14. In the optical path assembly 1, a reflecting mirror 13 is disposed corresponding to an imaging lens 12 and a corner cube 14, respectively, the imaging lens 12 being located between the laser 11 and the reflecting mirror 13.
The image detectors 2 are arranged in correspondence with the mirrors 13 in the two optical path components 1, respectively. The image detector 2 is used to detect images of the spots reflected by the mirrors 13 in the two optical path assemblies 1. The light spot is formed by converging diffuse reflected light rays sequentially through the imaging lens 12, reflecting by the reflecting mirror 13, changing the advancing direction by the pyramid prism 14 and reflecting again by the reflecting mirror 13 after the laser emitted by the laser 11 irradiates the surface of the measured material 8.
The thickness calculating device 3 is electrically connected to the image detector 2, and is used for calculating the thickness of the measured material 8 according to the images of the light spots reflected by the reflecting mirrors 13 in the two light path components 1 detected by the image detector 2.
The embodiment of the invention comprises the following steps: the laser thickness measuring instrument comprises two light path components 1, an image detector 2 and a thickness calculating device 3, wherein the light path components 1 comprise a laser 11, an imaging lens 12, a reflecting mirror 13 and a pyramid prism 14; the laser light emission direction of the laser 11 coincides with the thickness direction of the measured material 8 arranged between the lasers 11 in the two optical path components 1; after the laser emitted by the two lasers 11 irradiates the upper surface and the lower surface of the measured material 8 respectively, the light diffusely reflected by the upper surface and the lower surface is imaged by two groups of imaging lenses 12 which are symmetrically arranged correspondingly, reflected by a reflecting mirror 13, changed in advancing direction by a pyramid prism 14 and reflected by the reflecting mirror 13 again to form two light spots, and detected by an image detector 2 to obtain images of the light spots, and a thickness calculating device 3 calculates the thickness of the measured material 8 according to the images of the light spots; because of the imaging property of the pyramid prism 14, that is, the pyramid prism 14 can change the traveling direction of the incident light in parallel, that is, the light reflected by the reflecting mirror 13 to the pyramid prism 14 will be turned 180 ° and then return to the reflecting mirror 13, which is equivalent to reversely reflecting the light reflected by the reflecting mirror 13 in parallel; the reflected light is reversible by combining the imaging characteristic of the reflecting mirror 13, so that the light which is reversely reflected back to the reflecting mirror 13 is parallel to the original incident light of the reflecting mirror 13 and opposite in direction, namely, the light spots which are converged by the imaging lens 12 are rotated by 180 degrees by matching the pyramid prism 14 with the reflecting mirror 13; when the inclination angles of the reflecting mirrors 13 in the two light path components 1 are different during adjustment, or the laser thickness measuring instrument deforms during operation, so that the positions and angles of the reflecting mirrors 13 and the pyramid prism 14 slightly change, as long as the incident light rays and the reflected light rays of the pyramid prism 14 are still within the aperture range of the pyramid prism 14, light spots formed by the light paths are rotated 180 degrees, namely, the light spots detected by the image detector 2 are unchanged, and therefore, the image plane inclination error and deformation resistance are eliminated, and the thickness measuring precision of the measured material 8 is improved.
Fig. 3 is a schematic diagram showing an optical structure anti-deformation performance of a laser thickness measuring apparatus according to an embodiment of the present invention. Assuming that the positions of one mirror 13 and one pyramid prism 14 in the laser thickness gauge slightly change, see fig. 3, the dashed lines in the drawing show the original positions of the mirror 13 and the pyramid prism 14, and the solid lines in the drawing show the positions of the mirror 13 and the pyramid prism 14 after the change, it can be seen that even if the positions of the mirror 13 and the pyramid prism 14 slightly change, 180 ° rotation of the light spot can be realized, and the direction of the light spot emitted to the image detector 2 before the change is consistent.
The measured material 8 can be ultrathin plates, films and other materials, such as color steel plates, electronic films, conductive glass, pole pieces of new energy lithium batteries and the like.
For the laser 11, the lasers 11 in the two optical path assemblies 1 are coaxially aligned and focused at the midpoint of their lines. The measured material 8 may be arranged at the midpoint of their line. When the laser thickness measuring instrument works, laser light emitted by the laser 11 irradiates the upper and lower surfaces of the measured material 8 at the same time.
The perpendicular bisector of the line connecting the lasers 11 in the two optical path components 1 may be a central symmetry line of the laser thickness gauge, and the two optical path components 1 may be symmetrically arranged along the central symmetry line.
The present embodiment is not limited to the inclination angle of the imaging lens 12 with respect to the central symmetry line, and referring to fig. 2, the imaging lens 12 may be inclined at a certain angle toward the laser 11 as long as the imaging of the laser line is ensured to be parallel to the laser light emission direction. Preferably, referring to fig. 3, the optical axis of the imaging lens 12 is perpendicular to the laser light emitting direction and the sensitive surface of the image detector 2, respectively.
Referring to fig. 3, since the optical axis of the imaging lens 12 is perpendicular to the laser light emission direction, the laser line AB, that is, the object plane of the imaging lens 12, the image plane a 'B' after imaging by the lens is automatically parallel to the laser light emission direction (perpendicular to the central symmetry line MN). Further, due to the imaging characteristics of the pyramid prism 14, the object plane AB is imaged by the lens and then passes through the reflector 13, the pyramid prism 14 and the reflector 13, and then is directed to the image detector 2, the sensitive surface of the image detector 2 is parallel to the laser emitting direction, and the image plane a 'B' detected by the image detector 2 is automatically kept parallel to the laser emitting direction (perpendicular to the central symmetry line MN), so that automatic image flattening is realized. In the existing laser thickness measuring instrument (fig. 1), the image plane direction detected by the final image detector is determined by the angles of the reflecting mirror a and the reflecting mirror B, and the image plane direction may be inclined compared with the laser emitting direction due to the error necessarily existing in the actual angle, so that the light spot is defocused and dispersed to a certain extent, and the final thickness measuring precision is reduced. The laser thickness measuring instrument provided by the embodiment realizes automatic image flattening, eliminates the defect and improves the thickness measuring precision.
The present embodiment is not limited to the structure of the imaging lens 12, and the imaging lens 12 may be formed by combining two or more lens groups coaxial (the optical axis of each lens group is coaxial). Preferably, the imaging lens 12 is a convex lens. Compared with a plurality of lenses, the single convex lens does not need to be coaxial, and is convenient to debug and apply.
The reflecting mirror 13 is used for reflecting the light rays collected by the imaging lens 12 to the pyramid prism 14, and then reflecting the light rays emitted by the pyramid prism 14 to the image detector 2.
The corner cube 14 is used to change the direction of travel of the incident light in parallel, the image is rotated 180 °, but the handedness remains unchanged.
In this embodiment, the pyramid prism 14 may be an isosceles right triangle prism with the end plane facing the right angle.
The present embodiment does not limit the arrangement of the reflecting mirror 13 and the corner cube 14. Since the reflecting mirror 13 is disposed corresponding to the imaging lens 12 and the corner cube prism 14, respectively, the arrangement of the reflecting mirror 13 determines the arrangement of the corner cube prism 14. Fig. 4 is a schematic optical structure of a variation of the laser thickness gauge according to the embodiment of the present invention, referring to fig. 4, a small angle α of the reflecting mirror 13 in the length direction of the two optical path components 1 is opposite to the image detector 2, and the small angle α is smaller than 180 °, that is, the reflecting mirror 13 is inclined toward the imaging lens 12. Referring to fig. 2 and 3, the two mirrors 13 in the two optical path assemblies 1 face the image detector 2 at a large angle β in the length direction, which is larger than 180 °, i.e., the mirrors 13 are inclined away from the imaging lens 12. Comparing fig. 2, 3 and 4, it can be seen that the laser thickness gauge shown in fig. 4 has a larger volume than the laser thickness gauge shown in fig. 2 or 3, and based on this, fig. 2 or 3 is a preferred arrangement of the mirror 13, the size of the laser thickness gauge in the direction of the central symmetry line MN can be reduced.
Further, referring to fig. 2 or 3, the mirror 13 forms an angle θ (θ u And theta d ) The value of θ depends on the position of the pyramid prism 14, and should be as large as possible to reduce the size of the instrument in the direction perpendicular to the central symmetry line MN, so that the pyramid prism 14 is as close to the top of the imaging lens 12 as possible, but cannot contact the imaging lens 12, and cannot block light.
Preferably, referring to fig. 2, the surface of the corner cube 14 is perpendicular to the light reflected by the mirror 13. Such that the usable aperture of the corner cube is maximized and the light energy transmittance of the surface is maximized.
The corner cube 14 can translate in a direction perpendicular to the direction of light incidence (D in fig. 2 u And D d Shown) such that the reflected light rays of the two corner cubes 14 are respectively offset from the incident light rays by a lateral distance D u And D d ，D u And D d The size of (a) determines the position of the image a 'B' of the laser line AB on the sensitive surface of the image detector 2. Specifically, when the measuring instrument is adjusted, the D is adjusted u And D d So that the point a is imaged via both the upper and lower light paths to the midpoint a' of the sensitive surface of the image detector 2.
The pyramid prism 14 can translate along the incident direction of light, so that the distance position of the image plane can be adjusted, and the image planes of the upper imaging lens 12 and the lower imaging lens can be simultaneously overlapped with the sensitive plane of the image detector 2, namely, the overlapping of the positions of the image planes of the upper optical path and the lower optical path is realized, namely, the upper light spot and the lower light spot are simultaneously focused clearly.
During instrument installation and adjustment, the two reflectors 13 respectively form an included angle theta with the central symmetry line MN u And theta d May be different. Preferably, referring to fig. 3 and 4, the length direction of the reflecting mirror 13 in the two light path assemblies 1 is equal to the included angle delta of the laser light emitting direction. Thus, the two mirrors 13 respectively form an angle θ with the central symmetry line MN u And theta d The same applies. The advantage of symmetrical upper and lower structures is that the volume is minimized.
The image detector 2 is illustratively a charge coupled device.
The thickness calculating device 3 is used for calculating the distance between two light spots in the light spot image detected by the image detector 2; according to the formula t=m×h, the thickness of the measured material 8 is calculated, T is the thickness of the measured material 8, m is a specified coefficient, and h is the distance between two light spots in the light spot image. The specified coefficient m can be obtained through calibration.
In this embodiment, the thickness calculating device 3 may be a computer, and the computer may include a display unit, and the display unit may display the image of the foregoing light spot and information such as the thickness of the measured material 8.
The working principle of the laser thickness measuring instrument provided by the embodiment of the invention is briefly described below.
Referring to fig. 3, the light emitted by the two lasers 11 irradiates the measured material 8 respectively, and after the laser irradiation points B and a on the upper and lower surfaces of the measured material 8 are reflected by the upper and lower surfaces of the measured material 8, the light is converged and reflected by the upper and lower light paths respectively, and finally imaged on the sensitive surface of the image detector 2 to form two light spots B 'and a'. The image detector 2 transmits the light spot image signal to the thickness calculating device 3, the thickness calculating device 3 processes the light spot image, and calculates the distance h between the points A 'and B' in the light spot image, and the thickness T of the measured material 8 is as follows: t=m×h.
Compared with the prior art, the technical scheme provided by the embodiment has the following beneficial effects.
Since the optical axis of the imaging lens is parallel to the central symmetry line MN of the measuring instrument, the laser line AB, that is, the image plane a 'B' of the object plane of the imaging lens after imaging by the lens is automatically perpendicular to the central symmetry line MN of the measuring instrument. Because of the imaging characteristic of the pyramid prism, the image plane A 'B' can be automatically kept perpendicular to the central line MN of the measuring instrument no matter what the value of the included angle theta between the reflecting mirror and the central symmetry line is, the object plane AB is imaged by the lens and then is shot to the image detector after passing through the reflecting mirror, the pyramid prism and the reflecting mirror, and thus, the automatic image flattening is realized.
When the measuring instrument works, if deformation such as thermal deformation occurs, the included angle theta between the reflecting mirror and the central symmetry line MN is slightly changed, and the position and the angle of the pyramid prism are slightly changed, so long as the incident light ray and the reflected light ray of the pyramid prism are still within the aperture range of the pyramid prism, the imaging surface A 'B' formed by the light path still can be automatically kept perpendicular to the central line MN of the measuring instrument, and the deformation resistance function is realized.
Because a single image detector is used for simultaneously detecting images of two laser irradiation points on the upper surface and the lower surface of the measured material, the synchronism of the image acquisition and the processing of the upper optical path and the lower optical path is ensured, the problem that the upper independent measuring system and the lower independent measuring system of the traditional double-laser triangulation method are difficult to synchronize is thoroughly solved, and the influence of the up-and-down vibration of the measured material on the measurement is naturally eliminated.
In general, the laser thickness gauge utilizes the combination of a pyramid reflector (pyramid prism) and a plane reflector (reflecting mirror) to gather the upper image surface and the lower image surface together without inclination and defocus, so that the defocus error and the tilt error of the upper image surface and the lower image surface are eliminated in principle, and the defocus error and the tilt error caused by the deformation of micro thermal deformation, force deformation and the like of a measuring instrument device can be eliminated.
The above-described embodiments are merely exemplary, and it should be understood by those skilled in the art that the methods and systems described herein are not limited to the examples described in the detailed description. Other embodiments will occur to those skilled in the art from consideration of the specification of the invention, which is also within the scope of the invention as claimed.
Claims (7)
1. The laser thickness measuring instrument comprises two light path components (1), an image detector (2) and a thickness calculating device (3), wherein the light path components (1) comprise a laser (11) and an imaging lens (12), the laser (11) is positioned at the object plane of the imaging lens (12), the laser emergent direction of the laser (11) coincides with the thickness direction of a measured material between the lasers (11) arranged in the two light path components (1), the two light path components (1) are symmetrically arranged,
the light path component (1) also comprises a reflecting mirror (13) and a pyramid prism (14),
in the optical path component (1), the reflecting mirror (13) is respectively arranged corresponding to the imaging lens (12) and the pyramid prism (14), the imaging lens (12) is positioned between the laser (11) and the reflecting mirror (13),
the image detector (2) is respectively arranged corresponding to the reflecting mirrors (13) in the two light path components (1), the image detector (2) is used for detecting images of light spots reflected by the reflecting mirrors (13) in the two light path components (1), the light spots are formed by converging diffuse reflection light rays sequentially through the imaging lens (12), reflecting by the reflecting mirrors (13), changing the advancing direction by the pyramid prism (14) and reflecting again by the reflecting mirrors (13) after laser emitted by the laser (11) irradiates the surface of the tested material,
the thickness calculating device (3) is used for calculating the thickness of the measured material according to the images of the light spots reflected by the reflecting mirrors (13) in the two light path components (1) detected by the image detector (2).
2. The laser thickness gauge as claimed in claim 1, characterized in that the optical axis of the imaging lens (12) is perpendicular to the laser light exit direction and the sensitive surface of the image detector (2), respectively.
3. The laser thickness gauge as claimed in claim 1 or 2, characterized in that the two mirrors (13) of the two light path components (1) face the image detector (2) at a large angle in the length direction, the large angle being greater than 180 °.
4. The laser thickness gauge as claimed in claim 1 or 2, characterized in that the surface of the corner cube (14) is perpendicular to the light reflected by the mirror (13).
5. The laser thickness measuring instrument according to claim 1 or 2, wherein the length direction of the reflecting mirror (13) in the two optical path components (1) is equal to the included angle of the laser light outgoing direction, respectively.
6. The laser thickness gauge as claimed in claim 1 or 2, characterized in that the imaging lens (12) is a convex lens.
7. The laser thickness gauge according to claim 1 or 2, characterized in that the image detector (2) is a charge coupled device.
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