Dual screen electronic device and detachable display module thereof

A detachable display module assembled to a main device that has a first casing and a display screen, wherein the display screen is located on the first casing and exposed from a first opening of the first casing, and each of two opposited edges of the first casing has a groove and the detachable display module comprises:

• a second casing detachably positioned on the first casing, wherein the second casing has a second opening, and each of two opposite edges of the second casing has a protruding rib, and the two protruding ribs are respectively coupled to the two grooves, such that the second casing is slidingly connected to the first casing;
• a power supply module arranged on the second casing;
• an electrophoretic display module fixed to the second casing or detachably positioned on the second casing, wherein the electrophoretic display module has a display region exposed from the second opening;
• when the second casing is positioned on the first casing through the two protruding ribs and the two grooves, an orthogonal projection of the electrophoretic display module on the first casing overlaps the display screen, and a first display surface of the display screen faces away from a second display surface of the electrophoretic display module;
• and
• a control module selectively located on the second casing or located on the electrophoretic display module, wherein the control module is electrically connected to the electrophoretic display module and the power supply module.