Patent ID: 7524074

Claim:
A control knob comprising: a light guide ( 1 ) inserted between a light source ( 2 ) and an index ( 3 ) free to move in rotation about an axis (A), said light guide ( 1 ) comprising at least one entry surface ( 4 ) for light rays emitted by the light source ( 2 ), a first exit surface ( 6 ) of light rays towards the index ( 3 ), and said light guide ( 1 ) comprising a first optical part ( 4 , 8 , 15 , 16 ) to orient received light rays approximately parallel to the rotation axis (A) of the index ( 3 ), and a second optical part ( 5 , 22 , 14 , 17 , 18 , 19 , 20 ) to focus light rays towards at least the first exit surface ( 6 ); and a rotary body ( 35 ) hollowed out in the axial direction fitted with a reception part for reception of the light guide ( 1 ) sliding in a socket joint; the reception part including a recess ( 36 ) formed in the internal surface of the body ( 35 ) and an axial support part for axially supporting this light guide ( 1 ); and the axial support part comprising a plate ( 39 ) formed on the light guide ( 1 ) and support tabs ( 40 ) for this plate ( 39 ) formed on the body ( 35 ).