High-Q | חטיף 2

20

חטיף מס '2

אנגלית

Text II (Questions 18-22)

Of the dozens of flat-panel computer display technologies under development, organic semiconductors may be the most promising. With active layers only about a thousandth the thickness of a human hair, these displays were already demonstrated in their present form just over 10 years ago. Already the best of them are many times brighter per unit of area than conventional picture tubes, and can operate for over 30,000 hours. Significantly, 5 organic displays are fast enough to handle full-motion video, making them suitable for use not only as computer monitors but also as televisions. The most significant feature of these displays, however, is made possible by the basic characteristics of organic semiconductors themselves. Weak bonding between molecules in these materials permits the active layers to be deposited on thin, flexible plastic surfaces. 10 The resulting displays could be rolled up when not in use, or made to fit various different shapes. Both the active layers and their plastic foundation are so light that the weight of a computer monitor could conceivably be reduced to a few grams. The ability of organic semiconductors to form high-quality thin films on practically any flat surface could transform the display industry, because it allows engineers to deposit 15 display devices over large areas at very low cost - a critical requirement for large-area flat-panel displays. Conventional semiconductors, on the other hand, must be made on costly crystal structures known as wafers, chosen because their crystalline geometry is similar to that of the film. Someday it may be possible to create organic displays the size of an entire wall of a room, although so far the largest color displays, all of which are 20 experimental, measure about 12 centimeters diagonally.

18. The primary topic of the passage above is -

(1) the various uses of semiconductors in computer industry (2) the importance of computer displays (3) new technologies for computer displays (4) problems with current computer displays

19 . According to the passage, the feature of organic displays which makes them appropriate for television is their -

(1) size (2) speed (3) cost (4) weak molecular bonds

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