GB/T 27995.2-2025Semi-finished spectacle lens blanks - Part 2: Power-variation (English PDF)

Foreword

This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting is required.

This document is Part 2 of GB/T 27995 Semi-finished lens blanks. GB/T 27995 has been published in the following parts.

--Part 1: Monofocal and multifocal;

--Part 2: Gradient zoom.

This document replaces GB 27995.2-2011 "Semi-finished spectacle lens blanks Part 2: Specification for progressive lens blanks" and Compared with GB 27995.2-2011, in addition to structural adjustments and editorial changes, the main technical changes are as follows.

a) Added normative reference GB/T 10050 (see 5.1.1);

b) The 30 mm identification area has been deleted (see 5.4.1 of the 2011 edition).

This document is modified to adopt ISO 10322-2:2016 "Ophthalmic optics semi-finished spectacle lens blanks Part 2: Progressive addition and defocusing" Specifications for spectacle lens blanks.

Compared with ISO 10322-2:2016, this document has some structural adjustments. The structural number changes between the two documents are shown in the table below.

See Appendix A for the table.

The technical differences between this document and ISO 10322-2:2016 and their reasons are as follows.

-- Replaced ISO 13666 with the normative reference GB/T 26397 and added the normative reference GB 45184 (see Chapter 3) to adapt to my country's technical conditions and increase operability;

-- The normative reference GB/T 10050 replaced ISO 7944 (see 5.1.1) to adapt to my country's technical conditions and increase operability.

Sexuality;

-- The normative reference GB/T 17341 replaces ISO 8598 (see Appendix C) to adapt to my country's technical conditions and increase the Operability;

--The basic requirements (see 5.1 of ISO 10322-2:2016) have been deleted to adapt to my country's technical conditions and increase operability;

--Added geometric dimension test methods (see 6.3) to adapt to my country's technical conditions and increase operability;

--The marking content has been changed (see Chapter 7, 7.1.1 and 7.1.2 of ISO 10322-2:2016) to adapt to my country's technical conditions;

--The marking content has been changed (see Chapter 8, 7.2 and 7.3 of ISO 10322-2:2016) to adapt to my country's technical conditions;

-- The reference notes of this part (see Chapter 8 of ISO 10322-2:2016) have been deleted to adapt to the technical conditions of my country;

--Change the informative appendix "Measurement of the focal length of the additional surface by a focalometer" to a normative appendix (see Appendix C, ISO 10322-2:2016 Appendix B) to adapt to my country's technical conditions.

The following editorial changes were made to this document.

--In order to coordinate with the existing standards in my country, the name of the standard is changed to "Semi-finished Lens Blanks Part 2: Progressive Focus";

--Added Note 2 to Table 1.

Introduction

Semi-finished lens blanks are important components of prescription customized lenses. They can not only quickly meet customers' personalized needs, but also effectively improve the quality of lenses.

Improve lens processing time, optimize lens inventory, and reduce the risk of lens aging caused by long-term storage.

GB/T 27995 "Semi-finished lens blanks" is a recommended national standard that complements the mandatory national standard and consists of two parts.

-- Part 1: Monofocal and multifocal. The purpose is to establish the optical and geometrical properties of the surfaces of monofocal and multifocal semi-finished lens blanks.

Requirements and related test methods to improve processing level.

-- Part 2: Progressive focus. The purpose is to establish requirements and related requirements for the optical and geometrical properties of the surface of progressive focus semi-finished lens blanks.

Related test methods to improve processing level.

Semi-finished lens blanks Part 2: Gradient Zoom

1 Scope

This document specifies the requirements for the optical and geometrical properties of semi-finished lens blanks with finished progressive focus surfaces.

Test method.

This document applies to progressive focus semi-finished lens blanks.

2 Normative references

The contents of the following documents constitute the essential clauses of this document through normative references in this document.

For referenced documents without a date, only the version corresponding to that date applies to this document; for referenced documents without a date, the latest version (including all amendments) applies to this document.

GB/T 10050 Reference wavelength for optics and optical instruments (GB/T 10050-2009, ISO 7944:1998, IDT) GB/T 26397 Ophthalmic Optical Terminology (GB/T 26397-2011, ISO 13666:1998, MOD) GB 45184 Safety technical specification for components of ophthalmic products

3 Terms and definitions

The terms and definitions defined in GB 45184 and GB/T 26397 apply to this document.

4 Categories

Semi-finished lens blanks are classified as follows.

a) Single-focus semi-finished lens blanks;

b) Multifocal semi-finished lens blanks;

c) Progressive focus semi-finished lens blanks.

5 Requirements