5,245,794

43.50.Yw AUDIO END POINT DETECTOR FOR CHEMICAL-MECHANICAL POLISHING

AND METHOD THEREFOR

Isi Salugsugan, assignor to Advanced Micro Devices 21 September 1993 (Class $1/165.74); filed 9 April 1992

Sound generated by rubbing contact, between a polish pad and a hard surface underlying a softer material being removed, determines the polishing endpoint during chemical-mechanical planarization polishing of a wafer. The audio signal is filtered to the range 30 to 100 Hz. An integrator eliminates "transient noise spikes, and supplies a detection sig- nal only upon receiving the logic signal...to provide a predetermined over- polishing time prior to termination of polishing operations."--RWY

5,241,798

43.55.Dt DECORATIVE SUSPENDED CEILING

William J. Platt and Thomas E. Rose, assignors to National Rolling Mills

7 September 1993 (Class $2/311.2); filed 25 November 1991

The design makes the otherwise mundane "T" grid of a suspended acoustic tile ceiling into a decorative element. The bottom of the "T"

and thus the sectors conform more closely with the shape of the pipe or cable passing through the aperture. This in turn reduces the spacing between the slits and also reduces the noise which would leak through the seal.--CJR

46 37.....•$9 46

45 '38 41 43

accepts a colorful or textured strip, thus adding contrast and an appear- ance of depth to the grid.•CJR

5,241,799

43.55.Dt OPEN CELL LAY-IN PANEL

Martin D. Jahn, assignor to Chicago Metallic Corporation 7 September 1993 (Class 52/484); filed 10 December 1991

This open-cell lay-in panel is designed for use in a suspended ceiling. It is formed by at least two strip members that are connected together and are supported on flanges from the corners of the square grid opening. The strip members may be arranged to form an open cube or such, and they may have bent portions to give a different configuration to the structure.--CJR

5,243,153

43.55.Rg ACOUSTICAL BARRIER WITH ACOUSTICAL SEAL

Matthew J. Holwerda, assignor to Cascade Engineering, Incorporated

7 September 1993 {Class 181/208); filed 23 October 1991

This acoustical barrier has an aperture for a pipe or cable to pass through. The aperture has a number of radially extending slits which make sectors. One or more grooves are arranged in the sectors concen- trically about the aperture to increase the radial flexibility of the sectors,

5,239,792

43.55.Ti EAVESDROPPING-PROOF ROOM AND SOUND DAMPENING DEVICES THEREFOR

Shlomo Avni, assignor to Teletron Limited, Israel 31 August 1993 (Class $2/79.1); filed in Israel 9 June 1990

The patent describes a modular room designed to include walls that are substantially transparent (at least from one side), whereby any device implanted on the surface is immediately visible. Sound dampening devices for ventilating the rooms are also provided, which comprise a casing, a number of partitions dividing the casing into various compartments, and a number of channels connecting said compartments in such a way as to make a zigzag path of the air flowing through the device and the with- drawal of a fraction of the air from each compartment; this results in a dampening of sounds carried by the air.•CJR

5,241,512

43.55.Ti ACOUSTIC PROTECTION MATERIAL AND APPARATUS INCLUDING SUCH MATERIAL

Gilles Argy and Gustavo Alcuri, assignors to Hutchinson 2, France 31 August 1993 (Class 367/1); filed in France 25 April 1991

This material comprises a substrate with resonators formed on the substrate. The resonators have structural characteristics (density, modu- lus of elasticity, shear modulus, damping factor, piezoelectric factor, etc. ) and shape and/or size that are selected so that there is a predetermined resonance frequency associated with each resonator. This helps absorb sound energy and dissipate it in the form of mechanical heat energy and/or electrical energy.•CJR

2792 J. Acoust. Soc. Am., Vol. 95, No. 5, Pt. 1, May 1994 Review of Acoustical Patents 2792

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