automatic display dimmer - constant contrast

automatic display-dimmer elektor march 1983 The clarity and legibility of a light-emitting display is governed more by its contrast with the background at minimum brightness, than by the brightness of the illuminated characters. There is a direct relationship between brightness of the background and ambient light, and so a desirable feature is for the brightness of the display to adapt itself automatically to ambient light so that the contrast remains the same. The OPL 100, a monolithic integrated display- dimmer, has been specially developed for this purpose. automatic display- dimmer constant contrast Figure 1. The OPL 100 is an opto-electronic sensor, intended for automatically matching the brightness of light-emitting displays to the ambient light. The chip is accommodated in a transparent 8-pin dual-in- line package and includes a photo-sensitive diode in addition to the necessary control electronics. /?A, //:/",,z" -•/;‘ , wave determines the apparent brightness. Even if...