GA/T 1670-2019 in English

VALID

Forensic sciences—General technical specifications for comparison microscopes

Issued on:2019-10-14
Implemented on:2019-12-01
File Format:PDF
Delivery:Via email within 1~3 business days

Price(USD)： $160.00
$156.00

Standard No:	GA/T 1670-2019
Document status:	VALID
Title in English:	Forensic sciences—General technical specifications for comparison microscopes
Title in Chinese:	法庭科学比较显微镜通用技术要求
Language:	English
File Format:	Electronic (PDF)
Delivery:	Via email within 1~3 business days
Issued on:	2019-10-14
Implemented on:	2019-12-01
ICS Classification:	13.310-Protection against crime
Chinese Classification:	A92-Crime judging technology
Professional Classification:	GA-Security
Related Keywords:	standard technical dimensions standard requirements significance key technical indicators standard technical specifications comparison microscopes introduction analysis comparison microscope
Related Topics:	Microscopy Compare Microscope Optical System scientific testing techniques Microscope Optical System field microscope Super+ Contrast Microscope New Contrast Microscope comparison microscope Microscope focus Automated Contrast Microscope Fracture Microscopy Requirements for the use of high power mirrors Comparison of Several Microscopes Premium Comparison Microscope Microscope use requirements Microscope split ratio Microscope focus Microscope scientific ratio Comparison of Various Microscopes forensic science modern microscope technology microscope comparison comparison microscope Microscope standard use method Electron Microscope Specific Surface Optical microscope 2 forensic science Department of Technology and Science Novel Microscopy Requirements for Microscope Use Microscope Measurement Technology How to use a microscope Portable Comparison Microscope Mobile Contrast Microscope Mobile Comparison Microscope Stationary Contrast Microscope Super Microscopy Microscope distance ratio Focusing of the microscope court channel contrast microscope lower microhardness Microscopic testing technology use of comparative microscopes microscope profile How to use the microscope: Microscope split ratio microscopic defect Comparison of various microscopes focusing microscope illuminated microscope than microscope field microscope more than a microscope illuminated microscope Microscope use requirements Microscope Quality Requirements Near Field Microscopy Environmental Microscopy Comparison of Various Microscopes Technology Court Applied Technical Requirements Other requirements for prisms - general technical requirements for optical parts Leica contrast microscope Microscope lighting system Microscopy What are the microscopy techniques? international forensic science Microscopy Metrology Microscopy technology standards Methodological comparison of microcolumn gel method ga/t1012-2019 How to use a microscope How to use a microscope ga/t49-2019 How to use the microscope

本标准规定了法庭科学比较显微镜的基本参数、一般要求、试验方法、检验规则、标志、包装、运输和贮存。
本标准适用于具有两个物方视场和双光路的光学比较显微镜。

Introduction

Analysis of core parameters of the standard

Technical dimensions	Standard requirements	Significance for criminal investigation
Consistency of magnification	Difference in magnification of left and right objective lenses≤1.5%	Ensure no visual error when comparing physical evidence such as ballistic traces
Intersection of optical axes	Up and down≤20′/left and right≤60′	Maintain spatial consistency in observation of three-dimensional physical evidence
Resolution	≥1800NA line pairs/mm	Meet the inspection requirements of trace evidence (such as fibers and handwriting)

Detailed explanation of key technical indicators

Standard 4.2.7 clause specifically emphasizes that the comparison microscope must be equipped with a magnification correction mechanism, and the correction plate is used to achieve strict consistency of the magnification of the left and right system objective lenses. This requirement stems from the lesson learned in a gun-related case in 2018, in which the number of positive lines of the bullet was misjudged due to the magnification deviation of the equipment.

Standard evolution analysis

Compared with the old version of the standard, this version adds the electric focusing stability requirement (4.2.12), which responds to the demand for real-time transmission of microscopic images in the construction of digital courts. Typical applications include a cultural relic appraisal case in Hangzhou in 2020, in which electric focusing was used to achieve remote collaborative inspection of inspection materials.

Implementation suggestions

Key points for procurement verification:

When testing the photographic center offset according to Clause 5.2.9, it is recommended to use a digital micrometer with a 0.01mm accuracy
The transportation test should simulate the extreme environment of -40℃ to 55℃ (Clause 4.4)

More samples: NB/T 47013.2-2015 GB 50021-2001(2009) JGJ 94-2008

Sample only — not a preview of GA/T 1670-2019

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