Mysterious glass plate component

[Mr Evil]

I pulled this thing out of an old VCR. It consists of a glass plate with a grid of blobs deposited on the surface of both sides. There are metal strips along the angled edges on the right hand side, to which the wires are soldered.

What is it?

[DigitalJunkie]

I had a whole bunch of those when I was younger,never could figure them out..My best guess is some kind of delay-line? *Shrug*

[c2cthomas]

If you can get your hands on a service manual for that vcr the parts list might provide a clue. I'm guessing delay line but a path that short would make for a very short delay. Perhaps some type of filter?

[head_spaz]

It's a SAW filter/device.
Surface Acoustic Wave filter

A surface acoustic wave (SAW) is an acoustic wave traveling along the surface of a material exhibiting elasticity, with an amplitude that typically decays exponentially with depth into the substrate.

SAWs were first explained in 1885 by Lord Rayleigh, who described the surface acoustic mode of propagation and predicted its properties in his classic paper.[1] Named after their discoverer, Rayleigh waves have a longitudinal and a vertical shear component that can couple with any media in contact with the surface. This coupling strongly affects the amplitude and velocity of the wave, allowing SAW sensors to directly sense mass and mechanical properties.

[Steerpike]

It's a delay line. Usually used to delay the video signal for the time period of one TV scan line, so the VCR has simultaneous access to two adjacent TV lines for various signal processing tricks or dropout concealment.

[Mr Evil]

Thanks.