| 摘要 |
1,138,270. Luminescent display with a memory. NATIONAL CASH REGISTER CO. 1 Nov., 1967 [30 Nov., 1966], No. 49635/67. Heading G5C. A display device comprises a display surface 18, Fig. 2, which fluoresces in U.V. light and whose local light emitting properties vary according to the heat applied thereto; a plurality of heat applying magnetic elements 10 formed from a material having a closed hysteresis loop; a bias element 16 associated with each heating element 10 and settable by means of an information-bearing signal to one of two states to bias the elements 10 accordingly; and means for applying a switching signal to the elements 10 to cause those of them which are biased into the correct state to cycle around their hysteresis loop and thereby generate heat. Applications are described to both monogrammic and entire alphanumeric outputs. Display surface.-As described, the surface 18 is coated with a phosphor (e.g. Ag/Ni treated ZnCd sulphide) and bathed in U.V. light; such an arrangement fluoresces but is heat-quenched, as described in U.S. Specification 2,642,538, to display the required pattern. Heating application.-The heat pattern may be applied through a conducting plate shaped as an entire alphanumeric character, Fig. 7 (not shown), or directly by elements forming a monogrammic sign, Fig. 4. By applying the biasing signal to selected ones of the lines A . . . I selected fluorescent areas 41 are extinguished. Biasing.-The biasing elements 16 are each magnetically coupled to their associated heatgenerating element 10. Both exhibit uniaxial magnetic anisotropy; the coercivity of element 16 is greater than that of element 10; thus an applied field may switch the state of element 10 but not of element 16. A current passed through X-conductor 12 causes the magnetization of element 16 to rotate into the hard direction, and termination of the current results in its breakup into a multidomain state. No bias is therefore applied to element 10 and the latter is allowed to undergo heat-producing hysteresis cycles when an A.C. switching voltage is subsequently applied to Y-conductor 14. But if a current pulse along conductor 14 first causes element 16 to rotate into the easy direction, this prevents element 10 from cycling in response to the switching voltage. In the embodiment of Fig. 4, elements 39 act to bias elements 41, 38 is a common X-line, and A ... I are the Y-lines. The matrix 43 may be computer-controlled, Fig. 5 (not shown); or the bias element may be switched by means of a magnetic " writing pen ", Fig. 6 (not shown).
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