| 摘要 |
PURPOSE:To ensure a high-contrast display regardless of the brightness, by using a display plate with a high degree of brightness and using a light source when the brightness is low respectively after setting the light source at the back of the display plate. CONSTITUTION:For instance, when the brightness is high around a display meter at a service station, an output signal of ''bright'' detection is fed to an AND circuit 30 from a brightness detector 28. Thereafter, a hose 25 is lowered down for the supply of oil. Thus the output signal of a pulse oscillator 19 provided to a flowmeter 18 in the middle of an oil supply tube actuates a display plate via a counter circuit 20, a display driving circuit 22, etc. to display a figure of three digits. When the brightness becomes low around the display meter, an output signal of ''dark'' is led into an AND circuit 29 from the detector 28. At the same time, an FF circuit 31 feeds the output signal to a light source and a circuit of a motor 15. Then all light sources of the display meter 13 are turned on to display a figure of three digits through display parts 12, 12' and 12''. Thus a high-contrast display is possible regardless of the brightness. |
