Characteristics of the rubbing process

The rubbing process is employed for the manufacturing of LCDs with compensation being made for its problems. Typical problems and the current methods to eliminate or control them are discussed in this section. 

The rubbing machine is covered with a hood, and an exhaust fan is used to prevent the diffusion of the dust from the rubbing cloth and alignment material. After the rubbing process, a cleaning process is used to wash away particles of the rubbing cloth and alignment material from the surface of the substrate. 

The baking process consists of two stages, pre-baking and hard-baking. The pre-baking is to heat the substrate after coating it with polyimide to evaporate 

Since bits of the rubbing cloth and pieces of alignment material are embedded on the substrate by the rubbing process, a cleaning step is required after rubbing. The substrates are cleaned by using a normal process with purified water and ultrasonic vibration, and then dried. 

The applied voltage on a pixel is refreshed at 60Hz for normal TFT-driven LCD panels. Therefore, each pixel should hold an electric charge for 1/60sec = 16.7 msec, like a capacitor. If the charge of the pixel changes during this 

5 2005 Kohki Takatoh, Masaki Hasegawa, Mitsuhiro Koden, Nobtijodd Itoh, Ray Hasegawa and Masanori Sakamoto 

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Figure 14-7 is an example of the course of lubricated wear as followed by surface radioactivity. The progressive accumulation of reaction product on the rubbing track in the presence of a tagged compounded lubricant is shown by the first part of the curve, and the fact that this is the net resultant of simultaneous reaction and wear processes is demonstrated by the shape of the final portion of the curve, Sakurai it at. [11, 12, 13] found such behavior to be characteristic of the following sulfur compounds, singly and in combination sulfur, dibenzyl disulfide, diphenyl disulfide, dodecyl mercaptan and also these sulfur compounds in combination with stearic acid, benzyl chloride, chlorobenzene or hexachloroethane, The qualitative observations are credible enough, but because of experimental difficulties and the complications noted... 

R. M. Matveevsky [56] discussed the influence of temperature on lubricant additive action in terms of whether the additive functions by an adsorption/desorption mechanism or by a chemical reaction mechanism. If the additive is a blend of two components, one of which acts via adsorption and the other by reaction, and if the critical temperature of desorption is lower than the temperature at which the rate of chemical reaction of the other additive will contribute substantially to the lubrication process, then the critical desorption temperature will control lubricant failure. Thus, if the load induces frictional heating at the rubbing interface so that the conjunction temperature exceeds the critical desorption temperature, this will be the critical failure load. But if the surface exposed by desorption of the first additive reacts with the second additive at the temperature prevailing there, the failure load will be raised. Cameron and his co-workers [48, 57] used these concepts, although not as explicitly proposed by Matveevsky, to explain the behavior of multicomponent compounded lubricants containing dibenzyl disulfide and a commercial calcium petroleum sulfonate as the additives. The failure temperature characteristic of the calcium sulfonate as the sole additive was 468 K (195 C), whereas failure with dibenzyl disulfide was observed at 543 K (270 C). With the two-component additive, incipient failure began at ca. 473-493 K, which seems to mark a balance between desorption of the sulfonate and chemical reaction of the disulfide. As the temperature increased above 493 K, the reactivity of the disulfide became more apparent and the coefficient of friction decreased, until at 543 K, the temperature observed for the failure of the disulfide alone, the rubbing pieces scuffed. 

Thus, the new method for studying the molecular characteristics of the thermoplastic polymer transfer and wear products makes it possible to establish the orientation of mechano-chemical processes in the rubbing zone and to find ways of dispersion and wear control. The method also enables the wear mechanisms of antifriction polymers to be studied in terms of the transfer phenomena. 

The processes that constitute life take place in water (there may be a few exceptions but never mind). There are many substances characteristic of life, both simple molecules and highly complex ones, which interact readily with water. Common examples include sucrose, table salt, ethanol, rubbing alcohol (isopropyl alcohol or 2-propanol), and cotton, for example. Such substances are hydrophilic. As we shall see, most hydrophihc substances have a structural element in common with water. This fact is frequently captured in the idea like likes like. ... 

An impactor, illustrated in Fig. 29.6, resembles a heavy-duty hammer mill except that it contains no grate or screen. Particles are broken by impact alone, without the rubbing action characteristic of a hammer mill. Impactors are often primary-reduction machines for rock and ore, processing up to 600 ton/h. They give particles that are more nearly equidimensional (more cubical ) than the slab-shaped particles from a jaw crusher or gyratory crusher. The rotor in an impactor, as in many hammer mills, may be run in either direction to prolong the life of the hammers,... 

Attributes. Qualitative characteristics of products, whose presence or absence is subject to inspection to assess the acceptance quality level of a sample. (Inspection by variables involves numerical measurement) BS 1902 Pt 3.13 relates to the attributive properties of corner, edge and surface defects in refractories. See acceptance testing. Attrition. Particle-size reduction by a process depending mainly on impact and/or a rubbing action. 

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