| 摘要 |
A projection television lens system (23) has a device that distorts for telescopically adjusting a lens assembly, a tubular member (36) that carries lens elements (26, 28) of the assembly within a focus mount of the system. At one end of the lens assembly, there is provided a mounting site which is fixed in position with respect to the CRT (9). A device is then provided which connects the fixed mounting site to the tubular member (36). The thermal and structural characteristics of the device are selected so that the device itself distorts in response to temperature changes and thereby move the lens elements (26, 28) toward or away from another lens element (18) in response to, respectively, increased or decreased ambient temperature. In the most preferred embodiment, the fixed mounting site is on the focus mount at the image side of the lens assembly. The tubular member, carrying the lens elements (26, 28) and mounted within the focus mount, is connected to the focus mount by a polymer bar (41). The material of the bar and its dimensions are selected such that, in response to exposure to increased ambient temperature, the lens assembly is moved toward the other lens element (18) by an amount appropriate to maintain focus or substantially compensate for the distortion of the other lens element (18).
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