GB 17341-1998 Optics and optical instruments Lensmeter

This standard specifies the general specifications of focimeters. This standard applies to continuous display and digital display focimeters. GB 17341-1998 Optics and optical instruments Focimeters GB17341-1998 Standard download decompression password: www.bzxz.net

GB17341-1998
This standard adopts the main technical contents of ISO8598:1996 in a non-equivalent manner. This standard is proposed by the National Institute of Metrology. This standard is under the jurisdiction of the National Technical Committee for Standardization of Optics and Optical Instruments. The drafting unit of this standard is the National Institute of Metrology. The main drafters of this standard are Ma Zhenya, Wang Liru and Liu Wenli. This standard was first issued in May 1998.
1 Scope
National Standard of the People's Republic of China
Optics and Optical Instruments
Focimeters
Optics and optical instruments-Focimeters This standard specifies the general specifications of focimeters. This standard applies to continuous display and digital display focimeters. 2 Reference standards
GB 17341-1998
neq ISO 8598:1996
The clauses contained in the following standards constitute the clauses of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest versions of the following standards. GB2828-87 Sampling procedures and sampling tables for batch inspection (applicable to inspection of continuous batches) GB10050—88 Reference wavelengths for optics and optical instruments GB/T15464—1995 General technical conditions for instrument packaging ZBY002--81 Basic environmental conditions and test methods for transportation and storage of instruments JJG 580—96
Focusometer
JJG 866—94
Vertex power standard lenses
3 Definitions
This standard adopts the following definitions.
3.1 Focimeter
An instrument mainly used to measure the vertex power (D) and prism power (△) of eyeglass lenses (including contact lenses), determine the cylindrical axis direction of cylindrical lenses, print marks on uncut lenses and check whether the lenses are correctly installed in the frames. 3.2 Continuously indicating focimeter A focimeter with a continuous scale.
3.3 Digitally rounding focimeter A focimeter whose measured value is rounded to the nearest increment. 3.4 Vertex power
The reciprocal of the paraxial vertex focal length of the lens measured in meters. A lens has two vertex powers. 3.4.1 Back vertex power The reciprocal of the paraxial back vertex focal length of the lens measured in meters. 3.4.2 Front vertex power The reciprocal of the paraxial front vertex focal length of the lens measured in meters. 3.4.3 Power of a spectacle lens The back vertex power of a spectacle lens is usually defined as the vertex power of the spectacle lens. The unit of vertex power is the reciprocal of the meter (m-1), the unit name is "dimension diopter", and the symbol is "D".
Approved by the State Administration of Quality and Technical Supervision on May 5, 1998 652
Implementation on December 1, 1998
3.5 Prismatic power
GB17341-1998
The deviation of light after passing through a specific point on the lens. The unit of prismatic power is centimeters per meter (cm/m), the unit name is "prismatic diopter" and the symbol is "d".
3.6 Spherical power
The back focal power of a spherical lens is called spherical power. A spherical lens is a lens that makes the parallel rays of the paraxial line converge on one focus. This definition also applies to single-view aspherical lenses. 3.7 Astigmatic power
The difference between the two main focal powers in a cylindrical lens. A cylindrical lens is a lens that makes the parallel rays of the paraxial line converge on two mutually separated and orthogonal focal lines. Unlike a spherical lens, it has two main focal powers. One of the main focal powers can be zero, and the corresponding focal line is located at infinity. Complex curved lenses, lenses that combine spherical and cylindrical surfaces, and cylindrical lenses are all cylindrical lenses. Cylindrical lenses are also called astigmatic lenses.
4 Classification
Focusometers are divided into two categories according to the display mode: continuous display type and digital display type. According to the working principle, focalometers are divided into two categories: focalometers based on the focusing imaging principle and focalometers based on the automatic focusing principle. Based on the principle of focusing imaging, the focimeter is divided into two types according to the different observation methods: visual type and projection type. The visual focimeter uses a reading telescope system for observation; while the projection focimeter uses a projection lens and a projection screen for observation. 5 Basic parameters
5.1 Reference wavelength
The reference wavelength used to display the vertex power and prism power should be the green mercury line A = 546.07nm. 5.2 Measuring range
5.2.1 The measurement range of the vertex power is at least from -20D to +20D. 5.2.2 The measurement range of the prism power is at least from 0 to 5△. 5.2.3 The axis scale range of the cylindrical lens should be from 0° to 180°, and the baseline direction of the prism lens between 0° and 360° can be determined. 5.2.4 The measurable lens size should at least meet the requirements of measuring lenses with a diameter of 80mm and a thickness of 20mm. 5.3 Scale intervals
5.3.1 For a continuous display focal meter, the scale interval of the vertex power shall not be greater than 0.25D. The scale interval in the axial direction shall not be greater than 5° and may be interpolated to the nearest degree. The reading interval of the prism power shall not be greater than 1△. 5.3.2 For a digital display focal meter, when the measuring range is between -10D and +10D, the digital display increment of the diopter shall not be greater than 0.125D. When the measuring range exceeds ±10D, the digital display increment of the diopter shall not be greater than 0.25D. The digital display value shall reach two decimal places.
The digital display increment in the axial direction shall be 1°. The digital display increment of the prism power shall not be greater than 0.25△. 6 Technical requirements
6.1 The coordination of the movable parts of the focimeter should be moderate; the reading hand wheel should be flexible and accurately positioned, and the adjustable baffle should move smoothly; the printing mechanism should be easy to rotate, the printing mark should be clear, the dot diameter should not be greater than 0.5mm, and the lens pressing mechanism should be stable and reliable. 6.2 The imaging of the optical system of the focimeter should be clear, and the brightness in the field of view or on the projection screen and reading window should be uniform, without oil stains, water stains, mildew spots and other defects that obviously affect the reading.
6.3 The scale of the continuous display focimeter should be straight, uniform, with clear handwriting and no broken lines. The scale and the index line should be parallel and the positive and negative focal lengths should be marked with different colors. The positive and negative signs and digital display of the digital display type focal meter should be complete without broken lines, and the indication should be stable without obvious drift and flicker. 653
GB 17341-1998
6.4 When no lens is placed, the inherent prism power residual error of the focal meter shall not be greater than 0.14. 6.5 The parallax error of the visual and projection focal meters shall not be greater than 0.1A. 6.6 Requirements for the indication error of the vertex power
6.6.1 For focal meters of various display modes, the zero position error shall not be greater than ±0.03D. Among them, the zero position indication error of the spherical power and cylindrical power of the focal meter with a graduation of 0.01D shall not be greater than ±0.02D after the specified preheating time. 6.6.2 For focal meters of various display modes, the allowable difference between the measured value of the vertex power of the spherical standard lens (see JJG866-94 for regulations) and the standard value of the standard lens is shown in Table 1.
For digital focal meters, the tolerance between the measured value of the vertex power and the standard value shall be implemented according to the rounding rule with reference to Table 1. Table 1 Vertex Power Measurement Tolerance of Focimeter
Vertex Power Measurement Range
≥-10
≥-15
≥-20
6.7 Requirements for Indication Error of Prism Power
≤+10
≤+15
Diopter (D)
For focal meters with various display modes, the tolerance between the measured value of the prismatic power of prismatic standard lenses (see JJG866-94 for regulations) and the standard value of standard lenses is shown in Table 2.
For digital focal meters, the tolerance between the measured value of the correction power and the standard value shall be implemented according to the rounding rule with reference to Table 2. Table 2 Tolerance of prism power measurement of focal meter
Tolerance of prism power measurement
6.8 The deviation between the axis mark of the optical center of the lens and the optical axis of the focal meter shall not exceed 0.4mm. 6.9 The deviation between the axis mark in the direction of 0°～180° of the axis scale shall not exceed 1. 6.10 The parallelism deviation between the adjustable baffle and the axis scale in the direction of 0°～~180° shall not exceed 1°. Prism diopter (A)
6.11 The instrument shall meet the requirements of ZBY002 under the conditions of transportation and packaging, where the high temperature test shall be +40℃, the low temperature test shall be 25℃, and the free fall height shall be 250mm. 654
7 Inspection items and inspection methods
7.1 Appearance inspection
GB17341—1998
Use visual and hand feeling methods to check whether the instrument meets the requirements of 6.1 to 6.4. 7.2 Parallax inspection
7.2.1 Special inspection steps for visual focal meter7.2.1.1 Preparation steps
Use a piece of white paper to replace the inspected lens and focus the eyepiece crosshairs clearly. Then remove the white paper and focus the measurement target image of the instrument clearly. 7.2.1.2 Parallax elimination inspection
After focusing the crosshairs and target image according to 7.2.1.1, you can check whether the parallax has been eliminated. The observer moves his sight back and forth above the eyepiece and should not observe any obvious displacement between the crosshairs and the target image. 7.2.2 Use the visual method to check whether the instrument meets the requirements of 6.5. 7.3 Vertex power indication test
Use a set of spherical standard lenses (should meet the provisions of JJG866-94) to check whether the vertex power indication error meets the requirements of Table 1. 7.3.1 When no lens is placed, the vertex power indication of the instrument shall meet the requirements of 6.6.1. 7.3.2 Measure the spherical standard lenses in turn, and the vertex power indication of the instrument shall meet the requirements of 6.6.2. 7.4 Prism power indication test
Use a set of prismatic standard lenses (should meet the provisions of JJG866-94) to check whether the prismatic power indication error meets the requirements of Table 2. 7.4.1 When checking the prismatic power, the vertex power indication of the instrument should first be set to zero. 7.4.2 Measure the prismatic standard lens in turn. The prismatic power indication of the instrument shall meet the requirements of 6.7. 7.5 Inspection of the deviation between the axis mark of the optical center of the lens and the optical axis of the focal meter Use a 15D spherical standard lens (which shall meet the requirements of JJG866-94), first align the center so that the prism power is zero, and then mark the center axis. Then rotate the spherical standard lens 180°, align it again, and then mark the center axis. Half of the distance between the first and second center axis marks shall not be greater than 0.4mm. 7.6 Inspection of the deviation between the 0°～180° direction of the axis scale and the axis mark Place the cylindrical standard lens (which shall meet the requirements of JJG866-94) on the lens support seat, adjust its position, and focus so that the bright line formed by the image of the cylinder axis coincides with the 0°～180° direction of the axis scale; use the printing mechanism to mark the axis on the cylindrical standard lens. The angle between the marking line and the center line of the cylindrical standard lens shall not be greater than 1°7.7 Inspection of the parallelism deviation between the adjustable baffle and the axial scale plate in the direction of 0°~~180°Place the cylindrical standard lens (which shall comply with JJG866-94) on the lens support seat so that its reference edge is close to the adjustable baffle. Focus the cylindrical standard lens so that it forms an image in the direction of 0°~180°. Move the cylindrical standard lens and the adjustable baffle together so that the horizontal bright line passes through the center of the axial scale plate. At this time, the angular deviation of the horizontal bright line from the axial scale plate in the direction of 0°~180° (its value represents the angular deviation of the adjustable baffle from the axial scale plate in the direction of 0°~~180°) shall not be greater than 1°7.8 Transportation environment test
According to 6.11, the test is carried out according to the requirements of ZBY002. After the test, the instrument still meets the requirements of 6.6~6.10. 8 Inspection rules
8.1 Inspection classification
Product inspection is divided into factory inspection and type inspection. 8.2 Factory inspection
8.2.1 The sampling inspection of factory inspection shall be carried out in accordance with the single sampling inspection of GB2828. The special inspection level is S-3, and the qualified quality level is: AQL=4.0.
Batch range
51~150
151～500
Sample size
GB 173411998
Number of qualified judgments
8.2.2 The items of factory inspection are 6.1~6.10 of this standard. 8.3 Type inspection
8.3.1 Type inspection is carried out in the following situations: a) When new products are finalized and the prototype test of old products is carried out; b) After normal production, if there are major changes in structure, materials, and processes, which may affect product performance; c) During normal production, regular inspections should be carried out after regular or accumulated fixed production; d) When the product is resumed after a long period of suspension; e) When the factory inspection results are significantly different from the last type inspection; 1) When the national quality supervision agency proposes a requirement for type inspection. Number of unqualified judgments
8.3.2 Type inspection shall include all items specified in this standard, and samples for type inspection shall be drawn from qualified products after factory inspection. 8.3.3 Sampling for type inspection: At least three samples shall be drawn for each type of product. If one of the samples fails, the product of that type shall be judged as unqualified. 9 Marking, packaging, transportation and storage
9.1 Marking
9.1.1 Product marking
a) Manufacturer's name or trademark,
b) Product name:
c) Product model,
d) Factory number.
9.1.2 Packaging marking
The packaging marking of the instrument shall comply with the requirements of GB/T15464. 9.2 Packaging
9.2.1 The packaging of the instrument shall comply with the requirements of GB/T15464. 9.2.2 The instrument's packaging box should contain the instrument's manual and certificate. The instrument's manual should indicate the standard code that the instrument complies with. 9.3 During transportation, it is strictly forbidden to expose the instrument to sunlight, tumble, or vibrate violently. The instrument should be handled and loaded with care, and it is strictly forbidden to throw it. 9.4 The storage environment should be dry and ventilated to prevent the instrument from getting wet. 656
A1 Overview
GB 17341—1998
Appendix A
(Suggestive Appendix)
Measurement of the posterior vertex power of contact lenses
The measurement of the posterior vertex power of contact lenses is divided into two methods: in air and in solution. The focal meter method used in air is to measure the contact lenses using a focal meter based on the principle of focusing and imaging (not a focal meter based on the principle of automatic focusing).
A2 The design of the contact lens support seat shall not damage the measurement accuracy due to the introduction of excessive sag error. An example of a lens support suitable for measuring contact lenses is shown in Figure A1. A3 A special contact lens spherical standard lens should be used to calibrate the focal meter for measuring the back vertex power of contact lenses. This series of spherical standard lenses includes six types: -20.00D, -15.00D, -10.00D, -5.00D, +5.00D, +10.00D, +15.00D, and +20.00D.
A4 Contact lenses should have passed optical quality tests before measurement. (h.he)
Spectacle lens support
Contact lens support
d. -(4.500.50)mm
(h.--h.)=(0.55±0.02)mm
Figure A1 Example of a contact lens support (compared with the spectacle lens support it replaces) 6575 Inspection of the deviation between the axis mark of the optical center of the lens and the optical axis of the focal meter Use a 15D spherical standard lens (which should comply with the provisions of JJG866-94), first align the center so that the prism is zero, and then mark the center axis. Then rotate the spherical standard lens 180°, align it again, and then mark the center axis. Half of the distance between the first and second center axis marks shall not be greater than 0.4mm. 7.6 Inspection of the deviation between the 0°～180° direction of the axis scale and the axis mark Place the cylindrical standard lens (which should comply with the provisions of JJG866-94) on the lens support seat, adjust its position, and focus so that the bright line formed by the image of the cylinder axis coincides with the 0°～180° direction of the axis scale; use the printing mechanism to mark the axis mark on the cylindrical standard lens. The angle between the marking line and the center line of the cylindrical standard lens shall not be greater than 1°7.7 Inspection of the parallelism deviation between the adjustable baffle and the axial scale plate in the direction of 0°~~180°Place the cylindrical standard lens (which shall comply with JJG866-94) on the lens support seat so that its reference edge is close to the adjustable baffle. Focus the cylindrical standard lens so that it forms an image in the direction of 0°~180°. Move the cylindrical standard lens and the adjustable baffle together so that the horizontal bright line passes through the center of the axial scale plate. At this time, the angular deviation of the horizontal bright line from the axial scale plate in the direction of 0°~180° (its value represents the angular deviation of the adjustable baffle from the axial scale plate in the direction of 0°~~180°) shall not be greater than 1°7.8 Transportation environment test
According to 6.11, the test is carried out according to the requirements of ZBY002. After the test, the instrument still meets the requirements of 6.6~6.10. 8 Inspection rules
8.1 Inspection classification
Product inspection is divided into factory inspection and type inspection. 8.2 Factory inspection
8.2.1 The sampling inspection of factory inspection shall be carried out in accordance with the single sampling inspection of GB2828. The special inspection level is S-3, and the qualified quality level is: AQL=4.0.
Batch range
51~150
151～500
Sample size
GB 173411998
Number of qualified judgments
8.2.2 The items of factory inspection are 6.1~6.10 of this standard. 8.3 Type inspection
8.3.1 Type inspection is carried out in the following situations: a) When new products are finalized and the prototype test of old products is carried out; b) After normal production, if there are major changes in structure, materials, and processes, which may affect product performance; c) During normal production, regular inspections should be carried out after regular or accumulated fixed production; d) When the product is resumed after a long period of suspension; e) When the factory inspection results are significantly different from the last type inspection; 1) When the national quality supervision agency proposes a requirement for type inspection. Number of unqualified judgments
8.3.2 Type inspection shall include all items specified in this standard, and samples for type inspection shall be drawn from qualified products after factory inspection. 8.3.3 Sampling for type inspection: At least three samples shall be drawn for each type of product. If one of the samples fails, the product of that type shall be judged as unqualified. 9 Marking, packaging, transportation and storage
9.1 Marking
9.1.1 Product marking
a) Manufacturer's name or trademark,
b) Product name:
c) Product model,
d) Factory number.
9.1.2 Packaging marking
The packaging marking of the instrument shall comply with the requirements of GB/T15464. 9.2 Packaging
9.2.1 The packaging of the instrument shall comply with the requirements of GB/T15464. 9.2.2 The instrument's packaging box should contain the instrument's manual and certificate. The instrument's manual should indicate the standard code that the instrument complies with. 9.3 During transportation, it is strictly forbidden to expose the instrument to sunlight, tumble, or vibrate violently. The instrument should be handled and loaded with care, and it is strictly forbidden to throw it. 9.4 The storage environment should be dry and ventilated to prevent the instrument from getting wet. 656
A1 Overview
GB 17341—1998
Appendix A
(Suggestive Appendix)
Measurement of the posterior vertex power of contact lenses
The measurement of the posterior vertex power of contact lenses is divided into two methods: in air and in solution. The focal meter method used in air is to measure the contact lenses using a focal meter based on the principle of focusing and imaging (not a focal meter based on the principle of automatic focusing).
A2 The design of the contact lens support seat shall not damage the measurement accuracy due to the introduction of excessive sag error. An example of a lens support suitable for measuring contact lenses is shown in Figure A1. A3 A special contact lens spherical standard lens should be used to calibrate the focal meter for measuring the back vertex power of contact lenses. This series of spherical standard lenses includes six types: -20.00D, -15.00D, -10.00D, -5.00D, +5.00D, +10.00D, +15.00D, and +20.00D.
A4 Contact lenses should have passed optical quality tests before measurement. (h.he)
Spectacle lens support
Contact lens support
d. -(4.500.50)mm
(h.--h.)=(0.55±0.02)mm
Figure A1 Example of a contact lens support (compared with the spectacle lens support it replaces) 6575 Inspection of the deviation between the axis mark of the optical center of the lens and the optical axis of the focal meter Use a 15D spherical standard lens (which should comply with the provisions of JJG866-94), first align the center so that the prism is zero, and then mark the center axis. Then rotate the spherical standard lens 180°, align it again, and then mark the center axis. Half of the distance between the first and second center axis marks shall not be greater than 0.4mm. 7.6 Inspection of the deviation between the 0°～180° direction of the axis scale and the axis mark Place the cylindrical standard lens (which should comply with the provisions of JJG866-94) on the lens support seat, adjust its position, and focus so that the bright line formed by the image of the cylinder axis coincides with the 0°～180° direction of the axis scale; use the printing mechanism to mark the axis mark on the cylindrical standard lens. The angle between the marking line and the center line of the cylindrical standard lens shall not be greater than 1°7.7 Inspection of the parallelism deviation between the adjustable baffle and the axial scale plate in the direction of 0°~~180°Place the cylindrical standard lens (which shall comply with JJG866-94) on the lens support seat so that its reference edge is close to the adjustable baffle. Focus the cylindrical standard lens so that it forms an image in the direction of 0°~180°. Move the cylindrical standard lens and the adjustable baffle together so that the horizontal bright line passes through the center of the axial scale plate. At this time, the angular deviation of the horizontal bright line from the axial scale plate in the direction of 0°~180° (its value represents the angular deviation of the adjustable baffle from the axial scale plate in the direction of 0°~~180°) shall not be greater than 1°7.8 Transportation environment test
According to 6.11, the test is carried out according to the requirements of ZBY002. After the test, the instrument still meets the requirements of 6.6~6.10. 8 Inspection rules
8.1 Inspection classification
Product inspection is divided into factory inspection and type inspection. 8.2 Factory inspection
8.2.1 The sampling inspection of factory inspection shall be carried out in accordance with the single sampling inspection of GB2828. The special inspection level is S-3, and the qualified quality level is: AQL=4.0.
Batch range
51~150
151～500
Sample size
GB 173411998
Number of qualified judgments
8.2.2 The items of factory inspection are 6.1~6.10 of this standard. 8.3 Type inspection
8.3.1 Type inspection is carried out in the following situations: a) When new products are finalized and the prototype test of old products is carried out; b) After normal production, if there are major changes in structure, materials, and processes, which may affect product performance; c) During normal production, regular inspections should be carried out after regular or accumulated fixed production; d) When the product is resumed after a long period of suspension; e) When the factory inspection results are significantly different from the last type inspection; 1) When the national quality supervision agency proposes a requirement for type inspection. Number of unqualified judgments
8.3.2 Type inspection shall include all items specified in this standard, and samples for type inspection shall be drawn from qualified products after factory inspection. 8.3.3 Sampling for type inspection: At least three samples shall be drawn for each type of product. If one of the samples fails, the product of that type shall be judged as unqualified. 9 Marking, packaging, transportation and storage
9.1 Marking
9.1.1 Product marking
a) Manufacturer's name or trademark,
b) Product name:
c) Product model,
d) Factory number.
9.1.2 Packaging marking
The packaging marking of the instrument shall comply with the requirements of GB/T15464. 9.2 Packaging
9.2.1 The packaging of the instrument shall comply with the requirements of GB/T15464. 9.2.2 The instrument's packaging box should contain the instrument's manual and certificate. The instrument's manual should indicate the standard code that the instrument complies with. 9.3 During transportation, it is strictly forbidden to expose the instrument to sunlight, tumble, or vibrate violently. The instrument should be handled and loaded with care, and it is strictly forbidden to throw it. 9.4 The storage environment should be dry and ventilated to prevent the instrument from getting wet. 656
A1 Overview
GB 17341—1998
Appendix A
(Suggestive Appendix)
Measurement of the posterior vertex power of contact lenses
The measurement of the posterior vertex power of contact lenses is divided into two methods: in air and in solution. The focal meter method used in air is to measure the contact lenses using a focal meter based on the principle of focusing and imaging (not a focal meter based on the principle of automatic focusing).
A2 The design of the contact lens support seat shall not damage the measurement accuracy due to the introduction of excessive sag error. An example of a lens support suitable for measuring contact lenses is shown in Figure A1. A3 A special contact lens spherical standard lens should be used to calibrate the focal meter for measuring the back vertex power of contact lenses. This series of spherical standard lenses includes six types: -20.00D, -15.00D, -10.00D, -5.00D, +5.00D, +10.00D, +15.00D, and +20.00D.
A4 Contact lenses should have passed optical quality tests before measurement. (h.he)
Spectacle lens support
Contact lens supportwwW.bzxz.Net
d. -(4.500.50)mm
(h.--h.)=(0.55±0.02)mm
Figure A1 Example of a contact lens support (compared with the spectacle lens support it replaces) 6572 The instrument's packaging box should contain the instrument's manual and certificate. The instrument's manual should indicate the standard code that the instrument complies with. 9.3 During transportation, it is strictly forbidden to expose the instrument to sunlight, tumble, or vibrate violently. The instrument should be handled and loaded with care, and it is strictly forbidden to throw it. 9.4 The storage environment should be dry and ventilated to prevent the instrument from getting wet. 656
A1 Overview
GB 17341—1998
Appendix A
(Suggestive Appendix)
Measurement of the posterior vertex power of contact lenses
The measurement of the posterior vertex power of contact lenses is divided into two methods: in air and in solution. The focal meter method used in air is to measure the contact lenses using a focal meter based on the principle of focusing and imaging (not a focal meter based on the principle of automatic focusing).
A2 The design of the contact lens support seat shall not damage the measurement accuracy due to the introduction of excessive vector height errors. An example of a lens support suitable for measuring contact lenses is shown in Figure A1. A3 A special contact lens spherical standard lens should be used to calibrate the focal meter for measuring the back vertex power of contact lenses. This series of spherical standard lenses includes six types: -20.00D, -15.00D, -10.00D, -5.00D, +5.00D, +10.00D, +15.00D, and +20.00D.
A4 Contact lenses should have passed optical quality tests before measurement. (h.he)
Spectacle lens support
Contact lens support
d. -(4.500.50)mm
(h.--h.)=(0.55±0.02)mm
Figure A1 Example of a contact lens support (compared with the spectacle lens support it replaces) 6572 The instrument's packaging box should contain the instrument's manual and certificate. The instrument's manual should indicate the standard code that the instrument complies with. 9.3 During transportation, it is strictly forbidden to expose the instrument to sunlight, tumble, or vibrate violently. The instrument should be handled and loaded with care, and it is strictly forbidden to throw it. 9.4 The storage environment should be dry and ventilated to prevent the instrument from getting wet. 656
A1 Overview
GB 17341—1998
Appendix A
(Suggestive Appendix)
Measurement of the posterior vertex power of contact lenses
The measurement of the posterior vertex power of contact lenses is divided into two methods: in air and in solution. The focal meter method used in air is to measure the contact lenses using a focal meter based on the principle of focusing and imaging (not a focal meter based on the principle of automatic focusing).
A2 The design of the contact lens support seat shall not damage the measurement accuracy due to the introduction of excessive vector height errors. An example of a lens support suitable for measuring contact lenses is shown in Figure A1. A3 A special contact lens spherical standard lens should be used to calibrate the focal meter for measuring the back vertex power of contact lenses. This series of spherical standard lenses includes six types: -20.00D, -15.00D, -10.00D, -5.00D, +5.00D, +10.00D, +15.00D, and +20.00D.
A4 Contact lenses should have passed optical quality tests before measurement. (h.he)
Spectacle lens support
Contact lens support
d. -(4.500.50)mm
(h.--h.)=(0.55±0.02)mm
Figure A1 Example of a contact lens support (compared with the spectacle lens support it replaces) 657
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