In cooperation with Bunnie Studios, the blog of renowned hardware hacker Bunnie Huang (of Hacking the xbox and Chumby fame), we’re pleased to present an unusual “ware” that we acquired from one of our local Silicon Valley electronics surplus dealers.
(If you’re unfamiliar with the game, “Name that Ware” is a regular contest on Bunnie’s blog, where the goal is to learn about reverse engineering by analyzing unusual— or common but seldom-seen —hardware. You can read about the contest rules here, and you can see many pictures of past entries with this google image search, or even get a calendar featuring Name that Ware entries from prior years.)
In the detail photos that follow, we’ll show some close-up photos, and provide a little more physical description (without speculating too much as to the purpose of the different features). Can you identify this piece of hardware?
The outer edge of the object is a stainless steel frame, with a diameter of 150 mm with a flat indexing edge, giving it the basic shape of a “6 inch” IC wafer, by 2 mm in thickness.
Stretched tight across the frame is a complex flex circuit, made of multiple layers of copper and Kapton film. The kapton film covers both side of the flex circuit almost entirely, giving it a variously brown or greenish sheen, depending on how the light catches it.
If you look through the ware at a light source, here are a few things that you might want to notice: (1) There are rectangular shapes that fully transmit light through the Kapton layers— indicating that these are electrically isolated areas (2) there is a similar octagonal isolation ring around the entire “wafer,” (3) there are tiny points of white light showing, indicating the presence of drilled through-holes or vias, and (4) there is a very weak diagonal pattern of diagonal stripes visible in the background of the circuitry.
Here are a few close-up views of those front-side features:
In the last picture, you may notice a little flash of silver around those through holes.
On the bottom side of the object, the flex circuit is bonded to the steel frame.
Something else to notice if you look closely: In the gaps of the top copper layer, you can see a grid of selectively placed horizontal and vertical copper wires on different layers of the flex circuit.
So, if you have an inkling what you’re looking at, please leave your educated guesses (and reasoning) in the comments, here, or over at Bunnie Studios!
Update: We have the answer!