CN112697399A - Calibration method of lens measuring meter - Google Patents
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- CN112697399A CN112697399A CN202011443313.6A CN202011443313A CN112697399A CN 112697399 A CN112697399 A CN 112697399A CN 202011443313 A CN202011443313 A CN 202011443313A CN 112697399 A CN112697399 A CN 112697399A
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- 238000005259 measurement Methods 0.000 claims abstract description 94
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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
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- G01M11/02—Testing optical properties
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Abstract
The invention provides a calibration method of a lens measuring meter, which comprises the steps of measuring the indication variability and measuring the indication error, wherein a hemisphere standard device is adopted as a measuring tool to carry out calibration work, the lens measuring meter is placed on a standard hemisphere of the hemisphere standard device to read data, the hemisphere standard device is introduced as the measuring tool, and the hemisphere standard device is adopted to replace a plurality of measuring blocks and flat crystals in the steps of measuring the indication variability and the indication error, so that the error caused by overlapping the measuring blocks and the flat crystals in the existing measuring step when in use and measurement is avoided, the measuring accuracy and precision are improved, the number of the measuring tools is reduced, the operation is simpler, and the calibration of the lens measuring meter is simple, quick and high in accuracy.
Description
Technical Field
The invention relates to the field of optical instrument detection, in particular to a calibration method of a lens measuring meter.
Background
At present, the diopter of the lens is measured by adopting a lens measuring meter which adopts a mechanical transmission conversion principle and measures the diopter of the lens by measuring the bow height difference of curved surface chords on the concave and convex surfaces of the lens, and a corresponding reading is indicated by a surface pointer. The lens measuring meter has the advantages of simple structure, convenience in carrying and the like, so that the lens measuring meter is widely applied, but most of the calibration of the current lens measuring meter needs to be carried out through professional metering and detecting units, a microscope, a dial indicator, a dynamometer, a plurality of measuring blocks, a flat crystal, a projector and other more measuring tools are adopted in the calibration process, and the measuring blocks and the flat crystal are overlapped for use, so that the calibration and the measurement are complex and are difficult to operate.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the calibration method of the lens measuring meter is provided, the number of measuring tools in the calibration process is reduced by introducing the hemispherical standard, and the calibration measuring speed and the accuracy are high.
In order to solve the technical problems, the invention adopts the technical scheme that:
a method of calibrating a lens metrology table comprising the steps of:
measuring the variability of the indication value, namely selecting a standard hemisphere of which the standard value is in the range of the measurement range of the lens measurement table on a hemisphere standard device, placing the lens measurement table on the standard hemisphere, enabling a middle pointer of the lens measurement table to be perpendicular to a tangent line of a point on the contacted standard hemisphere, reading the value on the lens measurement table, continuously performing repeated measurement for multiple times, and taking the difference between the maximum value and the minimum value read from the lens measurement table as the variability of the indication value;
and measuring indicating value errors, namely respectively placing the lens measurement tables on each standard hemisphere of the hemisphere standard device, enabling a middle pointer of the lens measurement tables to be perpendicular to a tangent line of a point on the touched standard hemisphere, reading a numerical value on the lens measurement tables, and taking a difference value obtained by subtracting a standard value of the standard hemisphere from the numerical value read on the lens measurement tables as the indicating value error of the point.
The invention has the beneficial effects that: by introducing the hemisphere standard device as a measuring tool, the hemisphere standard device is adopted to replace a plurality of measuring blocks and flat crystals in the steps of measuring indicating value variability and indicating value error, so that errors caused when the measuring blocks and the flat crystals are stacked and used for measurement in the existing measuring step are avoided, the measuring accuracy and precision are improved, the number of the measuring tools is reduced, the operation is simpler, and the calibration of the lens measuring meter is simple, quick and high in accuracy.
Drawings
Fig. 1 is a flowchart of a calibration method for a lens metrology table according to an embodiment of the present invention.
Detailed Description
In order to explain technical contents, achieved objects, and effects of the present invention in detail, the following description is made with reference to the accompanying drawings in combination with the embodiments.
Referring to fig. 1, a calibration method for a lens measurement table includes the following steps:
measuring the variability of the indication value, namely selecting a standard hemisphere of which the standard value is in the range of the measurement range of the lens measurement table on a hemisphere standard device, placing the lens measurement table on the standard hemisphere, enabling a middle pointer of the lens measurement table to be perpendicular to a tangent line of a point on the contacted standard hemisphere, reading the value on the lens measurement table, continuously performing repeated measurement for multiple times, and taking the difference between the maximum value and the minimum value read from the lens measurement table as the variability of the indication value;
and measuring indicating value errors, namely respectively placing the lens measurement tables on each standard hemisphere of the hemisphere standard device, enabling a middle pointer of the lens measurement tables to be perpendicular to a tangent line of a point on the touched standard hemisphere, reading a numerical value on the lens measurement tables, and taking a difference value obtained by subtracting a standard value of the standard hemisphere from the numerical value read on the lens measurement tables as the indicating value error of the point.
From the above description, the beneficial effects of the present invention are: by introducing the hemisphere standard device as a measuring tool, the hemisphere standard device is adopted to replace a plurality of measuring blocks and flat crystals in the steps of measuring indicating value variability and indicating value error, so that errors caused when the measuring blocks and the flat crystals are stacked and used for measurement in the existing measuring step are avoided, the measuring accuracy and precision are improved, the number of the measuring tools is reduced, the operation is simpler, and the calibration of the lens measuring meter is simple, quick and high in accuracy.
Further, in the step of measuring the indication value variability, 5 times of repeated measurement is continuously carried out on the same standard hemisphere, and the difference between the maximum value and the minimum value is taken as the indication value variability.
As can be seen from the above description, the 5-time repeated measurement is more suitable and can improve the accuracy of the measurement.
Furthermore, in the step of measuring the indicating error, repeated measurement is continuously carried out on each standard hemisphere for multiple times, and the arithmetic mean value is taken as the measured value of the standard hemisphere.
As can be seen from the above description, multiple measurements are taken and the average value is taken as the measured value, thereby reducing the accidental error of the measurement and improving the accuracy of the measurement.
Further, in the indicating error measuring step, the standard values of the standard hemispheres of the hemisphere standard device are respectively-18D, -15D, -12D, -10D, -8D, -6D, -4D, -2D and +2D, +4D, +6D, +8D, +10D, +12D, +15D and + 18D.
According to the description, the range of the common lens measuring meter is-20D to +20D, the selected standard value covers the range of the range, and the measured sample data is relatively comprehensive compared with the range, so that the calibration and detection are more accurate.
Further, the method also comprises the following steps: preparation before calibration, checking the appearance of the lens measurement table, determining that no factors influencing the calibration measurement characteristics exist, and then performing the calibration step.
As can be seen from the above description, before the detailed measurement steps are performed, the appearance of the measurement table is checked to eliminate the systematic error that may affect the measurement result, thereby improving the accuracy of the calibration measurement.
Further, the method also comprises the following steps: and measuring the stroke of the measuring rod, manually operating the measuring rod, and reading on a dial plate when the measuring rod runs to the maximum value so as to obtain the stroke of the measuring rod of the lens measuring meter.
From the above description, the stroke of the measuring rod of the lens measuring meter is measured, and whether the measuring rod is misaligned or not is detected.
Further, the method also comprises the following steps:
measuring the mutual position of the pointer and the dial, observing the mutual position of the pointer and the dial of the lens measuring instrument by eyes, and measuring the distance between the upper surface of the tail end of the pointer and the surface of the dial by using a tool microscope and an indicating instrument.
Measuring the measuring force, namely, using a clamp to make a movable measuring head of the lens measuring meter contact with a measuring head of a force measuring instrument or an auxiliary accessory of the measuring head, and reading the force measuring value by the force measuring instrument when a pointer is at a zero position, namely, the measuring force of the lens measuring meter;
and measuring the zero error, namely placing the lens measuring meter on a 2-level flat crystal, enabling the movable measuring head and the fixed measuring head to be in contact with the flat crystal at the same time, and observing a pointer indication value on the lens measuring meter at the moment, namely the zero error.
As can be seen from the above description, measuring other possible misalignments of the lens meter improves the comprehensiveness of the calibration test.
Furthermore, the tool microscope adopts a five-time objective lens, the upper surface of the pointer and the surface of the dial are respectively focused by the tool microscope micro-motion lifting device, the pointer is used for reading, and the difference value of the two readings is the distance between the upper surface of the tail end of the pointer and the surface of the dial.
As can be seen from the above description, the tool microscope is used for measuring various lengths and angles, is particularly suitable for measuring various complicated tools and parts, is more suitable for measuring the distance between the pointer and the dial plate of the lens measuring meter by the five-fold objective lens, and is easier and more accurate in measuring operation.
Furthermore, the division value of the dynamometer is less than or equal to 1N or the resolution is less than or equal to 0.1N.
From the above description, the force measurable by the lens measuring meter is small, generally not more than 2N, and the force measuring meter with the division value less than or equal to 1N or the resolution less than or equal to 0.1N is selected, so that the reading is more obvious and more accurate measuring value can be obtained.
Referring to fig. 1, a first embodiment of the present invention is:
a method of calibrating a lens metrology table comprising the steps of:
preparing before calibration, checking the appearance of a lens measuring table, determining that no factors influencing the calibration metering characteristics exist, and then performing a calibration step;
measuring the stroke of the measuring rod, manually operating the measuring rod, and reading on a dial plate when the measuring rod runs to the maximum value to obtain the stroke of the measuring rod of the lens measuring meter;
measuring the mutual positions of the pointer and the dial plate, observing the mutual positions of the pointer and the dial plate of the lens measuring meter with eyes, and measuring the distance from the upper surface of the tail end of the pointer to the surface of the dial plate by using a tool microscope and an indicating meter; during measurement, five times of objective lenses are adopted, the upper surface of the pointer and the surface of the dial are respectively focused by a micro-motion lifting device of a tool microscope, the indicating meter is used for reading, and the difference value of the two readings is the distance between the upper surface of the tail end of the pointer and the surface of the dial; measuring the width of the tail end of the pointer and the width of a dial plate reticle on a tool microscope, wherein the reticle width is measured at least at a drawing position 3;
measuring the force, namely measuring the force by using a dynamometer, measuring by using the dynamometer of which the division value is less than or equal to 1N or the resolution is less than or equal to 0.1N, contacting a movable measuring head of the lens measuring meter with a measuring head of the dynamometer or an auxiliary accessory of the measuring head by using a clamp, and reading the force measurement value by using the dynamometer when a pointer is at a zero position, wherein the force measurement value is the measurement force of the lens measuring meter;
measuring zero error, namely placing a lens measurement meter on a 2-level flat crystal, enabling a movable measuring head and a fixed measuring head to be in contact with the flat crystal at the same time, and observing a pointer indication value on the lens measurement meter at the moment, namely the zero error;
measuring the variability of the indicating value, namely selecting a standard hemisphere of which the standard value on a hemisphere standard device is within the measuring range of the lens measuring meter, placing the lens measuring meter on the standard hemisphere for measurement, enabling a middle pointer of the lens measuring meter to be perpendicular to a tangent line of a point on the contacted standard hemisphere, reading the value on the lens measuring meter, continuously performing repeated measurement for 5 times, and taking the difference between the maximum value and the minimum value as the variability of the indicating value;
and measuring the indicating value error, namely respectively placing the lens measurement table on a standard hemisphere of which the standard value of a hemisphere standard device is-18D, -15D, -12D, -10D, -8D, -6D, -4D, -2D, +4D, +6D, +8D, +10D, +12D, +15D and +18D, reading the value on the lens measurement table when the middle pointer of the lens measurement table is perpendicular to the tangent line of a point on the contacted standard hemisphere, continuously performing repeated measurement for 3 times for each reading, taking the arithmetic mean value as the measured value of the point, and obtaining the difference value obtained by subtracting the standard value of the standard hemisphere from the measured value, namely the indicating value error of the point.
In other equivalent embodiments, the order of the above steps can be arbitrarily changed to perform calibration, the standard value of the standard hemisphere is not limited to the range in the first embodiment, and other standard value standard hemispheres can be selected according to the measuring range of the lens measuring table to be calibrated.
The second embodiment of the invention is as follows: according to the calibration method of the lens measurement table in the first embodiment, one lens measurement table is randomly selected, and an actual calibration measurement experiment of a zero error, a measurement force, an indication value variability and an indication value error is performed, wherein the experiment process and the experiment data are as follows:
1. environmental conditions
Selecting a proper laboratory environment for calibration, and calibrating the temperature of the laboratory: (20 +/-10) DEG C. Calibration chamber relative humidity: less than or equal to 80 percent. Before calibration, the lens measuring tables and the isothermal time of the calibration tool are not less than 1 h.
2. Equipment for calibration
Hemisphere standard device of lens measuring meter (precision: +/-0.08D), 2-grade plano-crystal, measuring instrument force measuring instrument (division value/resolution: 0.1N)
3. Calibration procedure
(1) Zero error
And (3) placing the lens measurement meter on a 2-level flat crystal to enable the movable measuring head and the fixed measuring head to be in the same straight line, reading on the lens measurement meter at the moment, and taking the indicating value of the lens measurement meter as a zero error.
The zero error measured in this experiment was 0D.
(2) Measuring force
And measuring by using a measuring instrument with division value less than or equal to 1N or resolution less than or equal to 0.1N. The movable measuring head of the lens measuring meter is contacted with the measuring head (or the auxiliary accessory of the measuring head) of the measuring instrument measuring meter by using the clamp, and the measuring value is read by the measuring instrument measuring meter. The measurement force is measured at a substantially zero position of the span. The measuring force can be measured by different types of measuring instrument measuring instruments or measuring head auxiliary accessories which meet the requirements.
The measured force was 1.2N.
(3) Variability of indication
The lens measurement table is placed on a +2D standard hemisphere for measurement, a middle pointer of the lens measurement table is perpendicular to a tangent line of a point on the touched hemisphere, numerical values on the lens measurement table are read, 5 times of repeated measurement are continuously carried out, and the difference between the maximum value and the minimum value is the indication value variability.
The variability of the measured index was 0D.
(4) Error in indicating value
The lens measuring table is respectively placed on each standard hemisphere (the nominal values are respectively-18D, -15D, -12D, -10D, -8D, -6D, -4D, -2D and +2D, +4D, +6D, +8D, +10D, +12D, +15D and +18D), the middle pointer of the lens measuring table is perpendicular to the tangent line of a point on the touched hemisphere, the numerical value on the lens measuring table is read, each reading is continuously measured repeatedly for 3 times, the arithmetic mean value is the measured value of the degree, and the difference value obtained by subtracting the nominal value of the standard hemisphere from the measured value is the indicating error of the point.
The error in the values is generally not in excess of the specification in Table 1.
TABLE 1 value error
Note: the calibration does not make a determination whether the measurement result is acceptable or not.
The results obtained for this error in the values are given in Table 2 below (unit: D):
TABLE 2 measurement of error in indicated values
In summary, according to the calibration method of the lens measurement meter provided by the invention, the hemispherical standard is introduced as the measurement tool, the hemispherical standard is adopted to replace a plurality of measuring blocks and flat crystals in the measurement indication value variability and indication value error steps, errors caused by stacking the measuring blocks and the flat crystals in the existing measurement steps for measurement are avoided, the measurement accuracy and precision are improved, the number of the measurement tools is reduced, the measurement operation is easier due to the adoption of the proper calibration tool in the calibration process, the method for removing the average value by multiple times of measurement is adopted, accidental errors are avoided, the detection accuracy is improved, the calibration of the lens measurement meter can be completed only by using the tool microscope, the indicator, the dynamometer, the 2-level flat crystal and the hemispherical standard, and the calibration of the lens measurement meter is simple, rapid and high in accuracy.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all equivalent changes made by using the contents of the present specification and the drawings, or applied directly or indirectly to the related technical fields, are included in the scope of the present invention.
Claims (9)
1. A method of calibrating a lens metrology table comprising the steps of:
measuring the variability of the indication value, namely selecting a standard hemisphere of which the standard value is in the range of the measurement range of the lens measurement table on a hemisphere standard device, placing the lens measurement table on the standard hemisphere, enabling a middle pointer of the lens measurement table to be perpendicular to a tangent line of a point on the contacted standard hemisphere, reading the value on the lens measurement table, continuously performing repeated measurement for multiple times, and taking the difference between the maximum value and the minimum value read from the lens measurement table as the variability of the indication value;
and measuring indicating value errors, namely respectively placing the lens measurement tables on each standard hemisphere of the hemisphere standard device, enabling a middle pointer of the lens measurement tables to be perpendicular to a tangent line of a point on the touched standard hemisphere, reading a numerical value on the lens measurement tables, and taking a difference value obtained by subtracting a standard value of the standard hemisphere from the numerical value read on the lens measurement tables as the indicating value error of the point.
2. The method of claim 1, wherein the step of measuring the variability of the indication value comprises continuously repeating the measurement 5 times on the same standard hemisphere, and the difference between the maximum value and the minimum value is the variability of the indication value.
3. The method of claim 1, wherein the step of measuring the reading error comprises repeating the measurement on each standard hemisphere a plurality of times in succession and averaging the measurements of the standard hemisphere.
4. The method of claim 1, wherein in the step of measuring the index error, the standard value of each standard hemisphere of the hemisphere etalon is-18D, -15D, -12D, -10D, -8D, -6D, -4D, -2D and +2D, +4D, +6D, +8D, +10D, +12D, +15D and +18D, respectively.
5. The method of calibrating a lens meter of claim 1, further comprising the steps of: preparation before calibration, checking the appearance of the lens measurement table, determining that no factors influencing the calibration measurement characteristics exist, and then performing the calibration step.
6. The method of calibrating a lens meter of claim 1, further comprising the steps of: and measuring the stroke of the measuring rod, manually operating the measuring rod, and reading on a dial plate when the measuring rod runs to the maximum value so as to obtain the stroke of the measuring rod of the lens measuring meter.
7. The method of calibrating a lens meter of claim 1, further comprising the steps of:
measuring the mutual positions of the pointer and the dial plate, observing the mutual positions of the pointer and the dial plate of the lens measuring meter with eyes, and measuring the distance from the upper surface of the tail end of the pointer to the surface of the dial plate by using a tool microscope and an indicating meter;
measuring the measuring force, namely, using a clamp to make a movable measuring head of the lens measuring meter contact with a measuring head of a force measuring instrument or an auxiliary accessory of the measuring head, and reading the force measuring value by the force measuring instrument when a pointer is at a zero position, namely, the measuring force of the lens measuring meter;
and measuring the zero error, namely placing the lens measuring meter on a 2-level flat crystal, enabling the movable measuring head and the fixed measuring head to be in contact with the flat crystal at the same time, and observing a pointer indication value on the lens measuring meter at the moment, namely the zero error.
8. The method of claim 7, wherein said tool microscope uses a five-fold objective lens, said tool microscope fine movement raising and lowering means is used to focus the upper surface of the pointer and the scale surface separately, and the difference between the two readings is the distance between the upper surface of the end of the pointer and the scale surface.
9. The method of claim 7, wherein the force gauge has a division value of 1N or less or a resolution of 0.1N or less.
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| GB586851A (en) * | 1944-06-14 | 1947-04-02 | British Thomson Houston Co Ltd | Improvements relating to optical systems |
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| CN104279946A (en) * | 2014-09-16 | 2015-01-14 | 大连理工大学 | Calibration method for spherical surface displacement measurement through electrical vortex sensor |
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2020
- 2020-12-08 CN CN202011443313.6A patent/CN112697399A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB586851A (en) * | 1944-06-14 | 1947-04-02 | British Thomson Houston Co Ltd | Improvements relating to optical systems |
| CN2095416U (en) * | 1991-02-09 | 1992-02-05 | 上海市商业科学技术研究所 | Degree measuring meter for ultra-thin glasses |
| JP2003227713A (en) * | 2002-02-05 | 2003-08-15 | Canon Inc | Three-dimensional shape measuring apparatus and its error calibration method |
| CN104279946A (en) * | 2014-09-16 | 2015-01-14 | 大连理工大学 | Calibration method for spherical surface displacement measurement through electrical vortex sensor |
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| [美]蒋百川: "《几何光学与视觉光学》", 30 November 2016 * |
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Application publication date: 20210423 |