Abbe principle

In the late nineteenth century. Dr Ernst Abbe and Dr Carl Zeiss worked together to create one of the world s foremost precision optics companies. The Abbe principle resulted in observations about measurement errors. 

The Abbe principle states that the reading axis and the measuring axis of a measuring instrument must be co-axial for maximum accuracy. Any separation of the two may lead to an error. 

The micrometer is one instrument which complies with the Abbe principle (Fig. 6.1) since the graduations are located along the same axis as the measurement being taken. 

In Figure 18.3, the optical system of Abbe Refractometer has been shown based on the critical angle principle. 

Until the advent of superresolution microscopes the only way to observe the minute world was based on the common Fourier-type microscopes. The maximum theoretical resolution limit for these apparatuses was established by Abbe, applying the Rayleigh-Fourier diffraction resolution rule [28]. The basic principle underlying the operational working of these ordinary microscopes is, in the eyes of Niels Bohr, a textbook example of Heisenberg uncertainty relations. 

Chapter 1 is concerned with the fundamental principles of image formation by a lens. These principles were first formulated by Ernst Abbe in 1873 and are basic to the chapters that follow. According to the Abbe theory, the image of an illuminated object is the result of a twofold diffraction process. First, the Fraunhofer diffraction pattern of the object is formed in the back focal plane of the lens. Second, the light waves travel... 

The principle of an electron microscope is based on the light microscope except that electrons are used instead of light. The resolving power of any microscope is given by Abbe s equation... 

FIG. 19.14. Working principle of ABB-Atom SECURE inherently safe district heating reactor. 

For sin 6 > nz/fti, total reflection of the light occurs at the bovmdary. This phenomenon is the principle of the popular Abbe refractometer (see Figure 4). A small amount of liquid sample is introduced between prisms Pi and P2. Usually, the prisms are kept at constant temperature using thermostated water. The light beam illuminates the prisms from below with the help of the mirror M. The prisms Pi and P2 are attached to a rotatable arm, A, which carries a marker and magnifier to facilitate accurate readings. 

The vernier caliper does not comply with this principle (Fig. 6.2). To ensure greatest accuracy of measurement, the workpiece being measured should be moved as close to the main beam as possible. The vernier depth gauge, however, does comply with Abbe s principle. 

Do not measure a workpiece at a position near the outer end of the jaws. Move the workpiece as close to the beam as possible to ensure greatest accuracy of measurement (see Abbe s principle Fig. 6.2). 

Vernier calipers Large measuring range on one instrument. Capable of internal, external, step and depth measurements. Resolution of LCD model 0.01 mm Resolution 0.02 mm. Point of measuring contact not in line with adjusting nut (Abbe s principle). Jaws can spring. Lack of feel. Length of jaws limits measurement to short distance from end of workpiece. No adjustment for wear... 

S. Nunns, Principles for Proof Testing of Safety Instrumented Systems in the Chemical Industry, Prepared by ABB Ltd. for the Health and Safety Executive Contract research report 428/2002, 2002, http //www.hse.gov.uk/research/crr pdf/2002/crt02428.pdf. 

The principle of an ebulliating catalyst bed is embodied in some proprietary designs, in contrast with the fixed-catalyst beds used in other versions of hydrocracking. The H-Oil process of Hydrocarbon Research, Inc. and the LC-Fining process jointly licensed by ABB Lummus Crest Inc., Oxy Research Development Co., and Amoco Corp. are examples of... 

Measurement of Refractive Indexes. Some of the techniques used to measure refractive indexes are the Becke line method (94), interference microscopy (95,96), Abbe refractometer (40,94,97-99), and ellipsometry (100). The Abbe re-fractometer (Fig. 5) can be used to determine the refractive indexes of materials belonging to all three optical symmetries. Its principle is based on the total reflection phenomenon occurring between a known and unknown isotropic media ... 

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