Patent ID: 6224221
Filing Date: 2001-05-01
Classification: G02B,G05G,H01H,Y10S

Abstract:
A rotatable knob of a control apparatus with electric components and an illuminating arrangement,comprising a light source which is positioned before a first light-transmitting body, said first light-transmitting body being situated within the rotatable knob, possessing a light entry surface arranged at a rotational center of said rotatable knob and having a peripheral light-output portion which terminates within a transparent housing part, said transparent housing part comprising an externally visible scale,wherein said transparent housing part further contains a second light-transmitting body fixed in the transparent housing, which second light-transmitting body is disposed between the scale and the peripheral light output portion of the first light-transmitting body, andwherein said second light-transmitting body comprises a total refection surface in a light path of light traveling from said light output part to said scale, which total reflection surface comprises an outer face forming an envelope of a cup-shaped frustum on which segment-shaped 90.degree. are arranged.