Magnifiers and Comparators Application Notes

Comparators

Comparators are a class of magnifiers that have a Meauring Reticle at their base. The Reticle is right-reading looking through the glass to enable contact inspection and measurement. Features, such as scales, circles, lines, grids, and angles contained on the Precision Reticle Pattern can be compared to features on the part being inspected.

In general the Field of View of a Comparator, (FOV) is directly related to the magnification of the Comparator. Within the same form factor or size, a 6X Comparator with a 25.4mm FOV will have a 19mm FOV at at 9X and a FOV of 15.8mm at 12X. Some reticle patterns, when partially obscured by high magnification Comparators are still very useful. With others the usefulness diminishes as the magnification increases.

Because of this relationship of Magnification to Field of View, all of the Reticle Pattern Types for the same form factor or size comparator may not be suitable for all magnifications that are associated with this Comparator. To help in determining the suitability of a particular and Reticle and Magnification combination for the Comparators that we sell, we have provided a cross-reference index and a set of usage notes in PDF format that will assist you in selecting the best combination of Comparators and Reticles for your application. This cross-reference guide also includes some of the comparators sold by others under their own brand name.

The optical quality of a Magnifier becomes very critical when used as a Comparator with a Reticle. Single simple lens systems are not satisfactory as the innate Chromatic Aberration and Focal Point changes that occur as you go off axis have a significant effect on the "In-Focus" part of the Reticle Pattern. The Field of View quickly becomes distorted as you move off the axis of the lens system; therefore, the "Sweet Spot" of the lens becomes very small and you become limited to a very small inspection area in the center of the lens. This is due to the Flatness of the Field and Wavelength span across the visible spectrum changing very rapidly as you go off axis. Color corrected Achromatic, anti-reflection coated lens systems with multiple elements are required for reasonable off-axis lens system performance.

All of the Magnifiers that we sell for use with our Reticles have high-quality, anti-reflection coated Achromatic Multiple Lens optics.

Simple Magnifiers, Lupes and Hastings Triplets

Magnifiers without reading reticles are generally referred to as Lupes, however some comparators are also called Lupes. All of the comparators we sell can have their Reticles removed and can serve as simple inspection Lupes.

There are various Lupes available for purchase. The Wide Field Inspection and Assembly Magnifier (MA003) has a 103mm X 129mm 2X lens, a 20mm X 25mm 5X lens, and a 15mm diameter 15X lens. This magnifier is ideal for manual inspection and assembly tasks. It can also be used with a wide array of our targets for measuring feature size and location on flat objects. In this application a Clear Optical Path Target can be placed pattern down against the object to be measured and the measurement can then be taken.

The Hastings Triplets (MA015, MA016, MA017) are the most popular High-Power Magnifiers available today. The next step up from the 20X Hastings is the Microscope. These Hastings feature a wide field, distortion-free, color corrected three element lens design offered in 7X, 10X and 20X magnification. Because of their flat, distortion-free large Field of View, they can be used for long periods of time without incurring excess eye strain and discomfort usually associated with lesser quality optics. These Pocket Magnifiers have extensive use in Printing, Manufacturing, Aerospace, Laboratory and Research Environments.