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Optical Comparator: What it can do for you?

Optical Comparator: What it can do for you?

What is an Optical Comparator

optical comparatorAn optical comparator projects magnified images of small product parts to identify measurement dimensions. Other than identifying dimensions, it also detects indentations, scratches, and other surface defects of the product. 

Optical comparators are widely used in the manufacturing and pharmaceutical industry. 

How Does It Work

There are three types of measurements. The simplest measurement is to shine light on the product part and project the silhouette on the optical comparator screen
Another way is to line up various points of the silhouette with the centre point of the screen and calculate how far the stage moved to reach those points. The last measurement process involves a software that analyses the dimensions of the image.

FAQs About Optical Comparators

1. What are the advantages of an optical comparator?

  • It greatly saves inspection time and eliminates parallax errors as it provides high magnification of the small, intricate parts.
  • It is budget friendly.
  • Users do not need any certification to operate it.

2. How do I use an optical comparator?

Firstly, place your product on the stage. Next, measure the product dimensions with the scale that is applied on the enlarged image.

3. Must the optical comparator be maintained or calibrated?

Regular calibration and maintenance is needed for the optical comparator to be accurate. Calibration should be done every 6 months to 3 years. The following are the most important characteristics that should be properly calibrated and verified in an optical comparator.

  • Length accuracy (X & Y axis)
  • Magnification accuracy (transmitted/contour illumination)
  • Magnification accuracy (reflected/surface illumination)
  • Squareness accuracy (X-Y axes)

Both maintenance and calibration are typically performed onsite by a technician.


The Optical Comparator remains one of the most cost effective and accurate instruments available in the market. It saves inspection time, is easy to use and very versatile. At Optical Gaging Products (OGP), we provide quality optical comparators like the QVI C-Vision to meet your various needs. Simply contact us at (65) 6741 8880 or send an email to for more information.

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