| 摘要 |
In an indicating instrument (1) for a vehicle, a pointer P indicating e.g. vehicle speed or engine revolutions, is formed by light. The front surface (2A) of the dial, having graduations (2b), is part-spherical such that it sticks out forwardly as its distance from the rotation shaft (4a) increases, and a light source (22) is disposed in front of the dial outwardly of the graduations (2b) to direct a light beam on to a mirror (21b) on the rotation shaft (4a) which reflects it onto the dial to form an optical point (P). Instead of being spherical, the dial may have a series of concentric circles of sawtooth cross-section (Figs 4, 5) or may be a holographic optical plate (Figs 6, 7) to reflect diffracting beams in a direction normal to the dial. A multi- dial indicating instrument system (Figs 3, 12, 13) comprises a cylindrical lens (22c) for converting a beam from a point light source to a substantially linear beam, first and second mirrors (13a, 13b) for dividing the linear beam, third and fourth mirrors (14A, 14B) for reflecting the divided beams to respective pointer forming reflectors (15b) of dials (2). The mirror (21b) may be pivoted to its shaft and urged by a spring (23) to a first position (Fig 9) casting a short optical pointer (Fig 11a). A bimetallic element (24) acts e.g. when ignition is switched on, to move the mirror to cast a long optical pointer (Figs 10, 11c) on to the graduations. <IMAGE>
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