This year Google has launched Google Nexus 7 tablet. The device has a 7 inch screen with 1920 x 1080 resolution. Amazon is not far behind. They launched Amazon Kindle Fire HDX tablet which has a screen with the same resolution as Nexus 7.
Apple needed something better to remain competitive, so brought to the market iPad Mini with Retina Display. The screen resolution is 2048 x 1536 and it has a much higher resolution than competing tablets, including here the Samsung Galaxy Note 8.