Difference between revisions of "AN0101 - Understanding LCD Panel Dimensions for Bezel Design"

Revision as of 11:31, 15 April 2014

In all new SIM's technical documentation you'll find a Mechanical Design Package, or "MDP". The Mechanical Design Package includes 3D STEP files that your mechanical designer can use to wrap an enclosure around a SIM.

There is also a simple 2D "blueprint style" drawing of each SIM in its MDP. For example, the SIM231 MDP has a 2D drawing which includes this diagram:

Here's a definition of the terms in this diagram:

Frame Outer

Frame Outer is the outer frame of the LCD display. Make sure if your bezel hangs down you give at least 2mm clearance outside this dimension.

Touch Panel Outer

The Touch Panel Outer dimension is the outer edge of a resistive touch panel's Mylar layers. Any pressure applied with a gasket should not overhang this edge or the outer edge of the plastic will deform and affecting the performance of the touch layers. Typically a gasket will start just inside this dimension.

Bezel Inner

The Bezel Inner dimension is the inner edge of any gasket as well as the inner edge of any bezel opening.

Touch Panel Visual Area

Touch Panel Visual Area is the area on the touch panel where inside this dimension there is no silver-looking conductive traces visible. These traces encircle a resistive touch panel and you don't want users to see this silver layer, so any bezel must come inside this dimension.

Touch Panel Active Area

Touch Panel Active Area is the area where the touch panel can be pressed. This usually extends a bit outside the LCD pixel area. If you have icons (etc) in the edges of the screen displayed, you want to make sure the full Touch Panel Active Area is accessible if possible. It helps the user press on those edges of the screen without having to dig their finger into the corner of your bezel.

LCD Active Area

The LCD active area is the actual area of the pixels. You want to center the Active Area in your bezel and work backwards from the center of the active area to where you mount the SIM. If you take the AA width or height and divide by the number of pixels (800 and 480 respectively) you’ll get the pixel pitch which should match exactly the specs in the technical reference manual (TRM) posted on the web.