Liquid crystal display unit

Abstract

Abstract PURPOSE: To effectively utilize electric power, by always keeping the display contrast of display unit constant, through the control of the drive voltage by providing the video elements for normal display and detecting external light passing. CONSTITUTION: The video element 12 for normal display is provided at a part of the display of the liquid crystal display element 11, and the drive voltage is fed from the voltage generator to it at all times. The external light 16 passing through the video element 12 is detected 17 and amplified 18. The output controls the generator 13 and the drive voltage is outputted by always keeping the contrast of the video element 12. Accordingly, each video element for information display to which the drive voltage from the generator 13 via the video element selection drive circuit 14 is applied can always be displayed with a given contrast. Thus, the temperature characteristics of liquid crystal is compensated and stable display is made, and power can effectively be utilized by controlling the drive voltage to the condition not having excess or deficiency. COPYRIGHT: (C)1979,JPO&Japio

Inventors

• 👤 Tomoo Yamamoto

Bibliographic Details