| 摘要 |
1,194,544. Indicating acoustic intensity distribution. BATTELLE DEVELOPMENT CORP. 1 Aug., 1967 [3 Aug., 1966; 8 Feb., 1967], No. 35229/67. Heading H4D. Apparatus for detecting the interference maxima and minima of two interfering ultrasonic beams comprises a thin film 25 of a cholesteric liquid (e.g. cholesterol chloride) sandwiched between two glass plates, two membranes, or a glass plate and a membrane, the optical properties of the film (reflection, transmission, birefringence, circular dichroism, optical activity, colour) being modified according to the ultrasonic intensity distribution. The apparatus may be used for detecting an ultrasonic hologram as described in Specification 1,194,543.
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