Cathode ray tube imaging

Recently, Kodak has put new inks on the market. Aluminum phthalocyanine (Figure 17.2, CAS Reg. No. 81422-13-1) is employed as the cyan colorant in this ink system. The new cyan ink exhibits a very yellowish shade of blue, almost turquoise. The absorption spectrum is compared in Figure 17.3 with that of C.I. Pigment Blue 15 3. Apparently, die absorption aroimd 550 nm is reduced compared with C.I. Pigment Blue 15 3. One of the characteristics of this ink system may be good reproducibility of cathode ray tube images widi little adjustment of colors. 

In SEM, the surface of the polymeric surface is scanned using an electron beam with the reflected or backscattered beam of electrons collected and displayed on a cathode ray tube screen. The image represents the surface contour of the scanned material. Because the surface must be conductive, most polymer surfaces must be overlaid with a conductive coating. Magnifications up to about 50,000 are carried out using SEM. 

In contrast to the TEM, the scanning electron microscope (SEM) works somewhat like a TV cathode-ray tube. An electron gun is used to scan a surface with the help of deflection coils and focusing lenses in a raster pattern, and the reflected electron signal is used synchronously to generate an image of very high magnification on a screen. The SEM has been in... 

Phosphors are an important, quality-determining component of cathode-ray tubes (Fig. 87). In the phosphor screen, modulated electrons are converted into a visible image. 

The cathode ray—a stream of electrons—has found a great number of applications. Most notably, a traditional television set (not the modern, thin, LCD screens) is a cathode ray tube with one end widened out into a phosphor-coated screen. Signals from the television station cause electrically charged plates in the tube to control the direction of the ray such that images are traced onto the screen. 

The most familiar display is a television or visual display unit associated with a computer. Both are based on the mature cathode ray tube (CRT) technology, whereby an electron beam selectively activates red, green, and blue (RGB) inorganic phosphors. It is an emissive technology and therefore produces bright images. 

In the scanning mode the electron beam focused on the sample is scanned by a set of deflection coils. Backscat-tered electrons or secondary electrons emitted from the sample are detected. As the electron beam passes over the surface of the sample, variations in composition and topology produce variations in the intensity of the secondary electrons. The raster of the electron beam is synchronized with that of a cathode ray tube, and the detected signal then produces an image on the tube. 

When the commercial OMA (Model 1205, Princeton Applied Research Corporation, Princeton, NJ) became available, we recognized its potential as a replacement for the photomultiplier detector. The vidicon detector surface was divided into 500 channels, the image could be seen on a cathode ray tube (CRT) monitor in real time, the intensity profile was available in digital form, the profile could be time-averaged for any desired number of video scans, and the final profile was stored in internal memory for transfer to an external output device. Not only had a considerable amount of work gone into its development and the verification of performance, but its potential for use for a variety of physical techniques would ensure the construction of enough units to support further development of the system. Moreover the need for low-light-level detectors for other purposes would lead to further improvements in detector devices. 

SEs and BSEs are typically detected by an Everhart-Thornley (ET) scintillator-photomultiplier secondary electron detector. The SEM image is shaped on a cathode ray tube screen, whose electron beam is scanned synchronously with the high-energy electron beam, so that an image of the surface of the specimen is formed [52], The quality of this SEM image is directly related to the intensity of the secondary and/or BSE emission detected at each x- and y-point throughout the scanning of the electron beam across the surface of the material [8],... 

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