[Breaking Down Samsung's Printer] More Than 70 Blue LEDs on Operating Portion [Part 6]

Nov 27, 2007
Nikkei Electronics Breakdown Team
The substrate of the operating portion bonded on the face panel. Two LED controller ICs "PT6961" made by Princeton Technology Corp. of Taiwan are seen at the left upper corner of the picture. A buzzer "KPM1205A" made by Kepo Electronics Co Ltd of Taiwan is seen on the left bottom of the picture. A semi-conductor that looks like a micro computer was mounted on the right side of the buzzer. The letters "CP6688AM, 0731, KCR, 646306" are printed on the surface.
The substrate of the operating portion bonded on the face panel. Two LED controller ICs "PT6961" made by Princeton Technology Corp. of Taiwan are seen at the left upper corner of the picture. A buzzer "KPM1205A" made by Kepo Electronics Co Ltd of Taiwan is seen on the left bottom of the picture. A semi-conductor that looks like a micro computer was mounted on the right side of the buzzer. The letters "CP6688AM, 0731, KCR, 646306" are printed on the surface.
[Click to enlarge image]
A black panel appeared when the substrate of the operating portion was taken apart.
A black panel appeared when the substrate of the operating portion was taken apart.
[Click to enlarge image]
To reduce unevenness in the color, the resin board was designed with variations in thickness. The material is a mixture of ABS resin and PMMA, a kind of acrylic resin.
To reduce unevenness in the color, the resin board was designed with variations in thickness. The material is a mixture of ABS resin and PMMA, a kind of acrylic resin.
[Click to enlarge image]

The upper half of the printer has been taken apart except for the substrate of the operating portion. We looked for screws to remove the substrate from the face panel, but couldn't find any. It is not secured by claws either.

The engineer gave it a thought for a while and started to pull away the substrate of the operating portion. "Wow! It is held down from end to end by double-sided tape," the engineer said. He peeled it off carefully but forcefully. It made a crunching noise.

"Isn't it extravagant?" the engineer said. The substrate torn from the operating portion had more than 70 blue LEDs on it. The locations of the keys are indicated by controlling the luminance of these LEDs, we understood. We could not find any mechanical switches on the face of the substrate where the blue LEDs are located. How does it detect operations of users?

The substrate of the operational portion was glued on a black panel stuck on the face panel. We took apart the black panel, wondering if this black panel is related to detection of operations. This black panel is also bonded by double-faced tapes on the whole area. The crunching noise was heard again.

The black panel turned out to be a simple ABS resin board with a thickness of about 3mm. The panel has about 70 holes in it. The holes are perhaps intended for adjusting the lights generated from the blue LEDs to realize the idealistic appearance.

The thick black panel would make it difficult to detect the pressure of a user's finger. The engineers reached the conclusion that when a user touches the face panel, the capacitance of the substrate changes. This change is perhaps detected as an operation by the user.

The face panel on which the substrate of the operating portion was bonded also comes with a twist. The face panel is translucent, with the shade of shiny black piano wire. If a thick black panel is bonded to it, the bonded area would look darker. To prevent this, the thickness of the area where the black panel is bonded was made thinner than the remaining areas.

"The design clearly shows their policy of placing priority on the appearance," an engineer murmured.