In the screenshots below, the mesh is shown in grey, with darkness indicating depth. Where the contrast is increased to better show fine structures, parts of the mesh exceeding the available range of grey tones are shown as yellow. Blue lines at the bottom and the right side are sometimes added to show the height profile along the axes of the cursor (red).
Sections:
All dimensions are in millimeters. The following sections explain how the measurements used in this drawing were obtained.
The result is that the case edge is typically between 1.9 to 2.0 mm above the PCB surface.
The case edge is typically about 2.0-2.2 mm above the PCB surface. The "step" on which the keyboard frame rests has a depth of about 1.1 to 1.2 mm and is thus roughly 1 mm above the PCB.
The measurements are between opposite points where the sensed height markedly falls off, and suggest a thickness of 1.4-1.5 mm. Given that the top of the wall is slightly curved, which can cause a drop to appear in the scan before the wall falls off in reality, some measurements are likely to be too short by up to one grid step (0.1 mm). We therefore consider the nominal wall thickness to be 1.5 mm.
The result is that the clearance varies considerably but is never smaller than 0.5 mm.
We obtain an overall wall thickness of 1.5 to 1.6 mm, and a "step" width of 0.4 to 0.5 mm. The PCB is closer to the wall than on the rear side, only 0.3 to 0.4 mm.
The first 0.5 to 0.6 mm below top of the case wall are unobstructed. Then the IR window begins, followed by the volume button with a peak at about 0.75 mm and the rest at 1.3 mm, and the camera button at about 0.9 mm.
The middle "hook" seems to be centered at the middle of the case. Most of these measurements are between edges that not perpendicular to the measurement direction and sometimes even rounded, and may therefore be fairly inexact.
The general observation is that that basic shape of this metal structure is a plane with some cut-outs into which shallow details have been stamped, and from which larger structures protrude. We can therefore measure all heights relative to this plane.
The following different features are being measured here:
At this location, the spacer is not in contact with the PCB directly, but rests on the light spreader, which has a thickness of about 150 μm. One can also see that the spacer has compressed the light spreader by about 50 μm.
These measurements show a systematic difference to the wall thickness of 1.5 mm. This can be explained by the shape of the display case, which transitions from the plateau to the wall through a small step. This step is almost invisible in the mesh at the top edge but can be clearly seen at the bottom edge:
With the scanning equipment equipment used, such a step is difficult to measure accurately due to the conical shape of the scanning needle. Combining results from the top and the bottom edge (below), we estimate the step to have a width of about 0.4±0.1 mm.
We show distances corrected for the step width in parentheses after the original measurement. The minimum distance between slider metal and the case is thus 0.1 mm, with the gap sometimes growing to about 0.5 mm (zones A a and B) or even 0.8 mm (zone C).
The measurements also show a significant difference between the distance between slider and the outside wall of the display on the left and on the right side. We did not examine this further, but consider it possible that the difference may have been caused the 0.4 mm step entering some of the measurement while being absent from the others.
Note that, while the scan shows a clearly visible rotation in the XY plane, its effect on measurements is negligible. (E.g., the real distance between the two columns is only about 0.02% larger than its X distance.)
2016-10-26 23:39:12 UTC