Abstract: A belt tension sensor includes an armature that is displaced in relation to belt tension and an optical sensing mechanism that detects armature displacement as a measure of belt tension. In a first mechanization, a lens element is mounted on the armature for movement therewith, and light emitted by a light source passes through the lens element before impinging on a light responsive element; the lens element variably diffuses the emitted light in relation to the belt tension, and the light impinging on the light responsive element provides a measure of the belt tension. In a second mechanization, the armature includes a protuberance that abuts and variably collapses a compressible optical waveguide to vary its optical transmissivity in relation to the armature displacement, and the optical transmissivity of the optical waveguide provides a measure of the belt tension.

Abstract: A belt tension sensor includes an armature that is displaced in relation to belt tension and an optical sensing mechanism that detects armature displacement as a measure of belt tension. In a first mechanization, a lens element is mounted on the armature for movement therewith, and light emitted by a light source passes through the lens element before impinging on a light responsive element; the lens element variably diffuses the emitted light in relation to the belt tension, and the light impinging on the light responsive element provides a measure of the belt tension. In a second mechanization, the armature includes a protuberance that abuts and variably collapses a compressible optical waveguide to vary its optical transmissivity in relation to the armature displacement, and the optical transmissivity of the optical waveguide provides a measure of the belt tension.

Abstract: A backlighting device for a backlit graphic display used in an instrument panel of an automobile. The backlighting system involves the use of a fluorescent light source and a lightpipe which is tailored for use with the fluorescent light source so as to promote uniform transmission of light to the display, and to achieve a suitable level of light intensity when backlit by a minimal number of light sources. The backlighting system further involves forming the lightpipe from a material which readily transmits light, and preferably is sensitive to ultraviolet radiation, so as to enhance the lighting capability of the light source while also producing an aesthetically pleasing appearance for the display.

Abstract: An illuminated annunciator as in a gear selector has gear designation letters always lit and a ring around each letter selectively lit to indicate the active gear range. A generally conical light pipe with a conical central cavity has at one end an annular emitting surface adjacent the ring and at the other end it is illuminated by an LED. Another LED within the conical cavity illuminates the letter directly as well as via reflection from the wall of the cavity.