When you first look at Samsung Galaxy S4 Digitizer and LCD screen assembly and Samsung Galaxy S3 Digitizer and LCD screen side by side, the most significant difference is that the outer edges of the S4 are apparently smaller than that on S3. The width between the edge and the main display area is only 1.5 mm, less than half of that of the S3 which makes more space to fit a larger screen. There is another hole on the upper left side of the Samsung Galaxy S4 which doesn’t appear on any other phones before it may be some sort of sensor or an LED notification.
When we turn over the two LCD screen assemblies, we can easily see that the flex cable connectors on the two screens are in different positions, for S4, the flex cable is on top, but for S3, the flex cable is at the bottom.
When we look at the screen assembly from this angle, we can see that both the glass lens and digitizer behind it are thinner when compared with the S3.
Now let’s take a look at the Samsung Galaxy Note II Digitizer and LCD screen compared with the Samsung Galaxy S4 Digitizer and LCD screen. The Note II is really a big phone, the edge around the screen of the Note II is 2.8mm, nearly double that of the S4 and the Note II has two flex cables on the back while S4 only has one. The thickness of Note II is much thicker than the S4, especially the glass lens.