Printed circuit board, method for determining engagement state between printed circuit board and flexible printed circuit and display device

A printed circuit board, comprising:

• a substrate;
• a connector fixed on the substrate, and configured to be connected with a flexible printed circuit, wherein the connector comprises a plurality of first pins and at least one secondary pin, and the first pins are separate from the secondary pin;
• the first pins are configured to be engaged correspondingly with a plurality of second pins of the flexible printed circuit;
• the secondary pin is located in an extension direction of the first pin on a side of the first pin engaged in correspondence with the second pin;
• and
• a determining circuit connected with the secondary pin, wherein the determining circuit is configured to determine together with the secondary pin an engagement state between the first pins and the second pins.