Objectives working distance

Microscope Objective Working Distance (mm) Spot Diameter (2 Wo, pm, for 514.5 nm laser) Observed Depth of Focus (5a ) Power Density" (W cm )... 

The standard 40x objective is the 0.65-NA version, rather than the higher resolution but shorter working distance 0.85-NA objective. 

An industrial microscope with a long-working distance 20 X objective is used for the collection of the chromatic interference patterns. They are produced by the recombination of the light beams reflected at both the glass/chromium layer and lubricant/steel ball interfaces. The contact is illuminated through the objective using an episcopic microscope illuminator with a fiber optic light source. The secondary beam splitter inserted between the microscope illuminator and an eyepiece tube enables the simultaneous use of a color video camera and a fiber optic spectrometer. 

FIGURE 8.5 Effect of dispersion compensation in two-photon depth imaging. Image acquisition of thick mouse kidney sample collected in a series of z-sections at different depths, which demonstrates that MIIPS compensated pulses attain better signal, and deeper penetration than those with GDD-only compensation. The image size is about 100 pm. The objective used is Nikon 60 x 1.45 NA, with working distance of 130 pm. (From Xi et al. Opt. Comm. 281(7) 1841-1849, 2008. Used with permission.)... 

Long work / distance /Sample surtace Focused spot l objective ... 

The nature of solid, liquid or gaseous inclusions that may be found within transparent inorganic glass or crystalline materials can be determined by Raman microprobe techniques without breaking up the sample (39). Other analytical techniques, such as mass spectroscopy or electron microscopy, that may be used to obtain such information require destruction of the original sample. This capability of the microprobe is useful if one wants to analyze inclusions in a material before and after a sample treatment. The only limitation is that the position of the inclusion in the material must be located within the working distance of the objective lens in the microscope (39). 

Microneedle puller micromanipulator and needle holder inverted microscope, preferentially equipped with both short (x 63 or X100) and long (x40) working distance phase objective lens glass capillaries ... 

Figure 12.22. Schematic of Dilor Superhead fiber-optic probe head. The objective lens may be replaced to permit different working distances and focal spot diameters.

One mitigating feature of LCP polymer microstructures is that they often are quenchable, due to the relatively slow kinetics of ciystallization. Thus one can examine microstructures at resolutions that are inaccessible while the specimen is enclosed in a heating stage. (Objectives with the highest numerical apertures have a short working distance, and all objectives should be protected from above-ambient temperatures.) However, the gain in resolving power may not be sufficient to offset the decrease in microstructural scale. 

The working distance between the specimen and objective lens is determined by magnifications of the lens. Estimate the difference in the working distance for objective lens with power of 5 x, 20 x and 50 x. 

The working distance and aperture size, illustrated in Figure 4.4, are the operation variables that strongly affect depth of field. We often need to make full use of the most important feature of an SEM the three-dimensional appearance of topographic images. Recall that the depth of field is related to the resolution (R) and the convergence angle of objective aperture (or) as (Equation 1.7). 

Figure 1.30 Varian s patented side-port adaptor and objective, allowing for the measurement of samples that are too large to be accommodated under the objective s standard 24-mm working distance, illustration courtesy of Varian Corporation.

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