AN0101 - Understanding LCD Panel Dimensions for Bezel Design

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 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 Visual Area is the area you can expose to the user. It is inside the conductive trace layer which looks silver to the eye and you don’t want the customer to see – your bezel edge should be inside that.

The Bezel Inner dimension is the critical dimension – that should be where your bezel comes exactly to.

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.

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.