GB/T 40177-2021 English PDF (GBT40177-2021)

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GB/T 40177-2021: Optics and optical instruments - Ophthalmology - Graduated dial scale
GB/T 40177-2021
Optics and optical instruments-Ophthalmology-Graduated dial scale
ICS 11.040.70
C40
National Standards of People's Republic of China
Optics and optical instruments ophthalmology index dial scale
(ISO 8429.1986, IDT)
Released on 2021-05-21
2021-12-01 implementation
State Administration of Market Supervision and Administration
Issued by the National Standardization Management Committee
Table of contents
Foreword Ⅲ
1 Scope 1
2 System description 1
3 Example 1
Preface
This standard was drafted in accordance with the rules given in GB/T 1.1-2009.
The translation method used in this standard is equivalent to ISO 8429.1986 "Optical and Optical Instruments Ophthalmology Index Scale."
Please note that some of the contents of this document may involve patents. The issuing agency of this document is not responsible for identifying these patents.
This standard is under the jurisdiction of the National Optical and Photonics Standardization Technical Committee (SAC/TC103).
Drafting organization of this standard. China Institute of Metrology.
The main drafters of this standard. Zhang Jiyan, Gao Mingliang, Dingxiang, Liu Wenli, Sun Jie, Yang Lei.
Optics and optical instruments ophthalmology index dial scale
1 Scope
This standard is used in the design of human eye optical parameters and human eye correction lens measuring instrument scales, reticles or other display methods.
The angular coordinate system is specified.
2 System description
The coordinate system specified in this standard, sometimes called the TABO system, is described as follows.
a) It is used to describe the angular direction of the cylindrical lens axis when the refractive error of the human eye or the refraction effect of the contact lens/spectacle lens;
b) When used to describe the prism effect of the contact lens/glasses lens in the polar coordinate system, the angular direction of the prism base;
c) When used to describe the curvature of a surface (such as. cornea or lens), the angular direction of the principal curvature meridian.
Regardless of whether it is for the right eye or the left eye, the coordinate system is the same. When using this coordinate system, it is described as a person observing from the outside
What the eyes and spectacle lenses look like when they are placed correctly in front of the eyes.
The 0° axis of the coordinate system is horizontal. If the number starts from 0° to 360°, the 0° axis is usually on the right part of the horizontal axis, in reverse time
An increase in the angle value of the needle direction by 90° corresponds to the vertical axis. When used to define the cylinder axis or the direction of the principal curvature meridian, the angle value should be expressed as
The value is 0°~180°. When used to define the orientation of the prism substrate, use the contact point of the prism substrate with the TABO ring to indicate the angle value.
Shown as a value from 0° to 360°.
3 Examples
Using the coordinate system described in Clause 2 above, an example of the design of the index plate scale is shown in Figure 1.Although it is indexed at a specific angle
The design is displayed, but this does not mean that other designs cannot be used, nor is it the scope and intent of this standard.