The present invention proposes a backlight module including a back bezel made of memorizing alloy materials and a heating apparatus for heating the back bezel. The back bezel is curved upon a condition that a temperature is equal or over a predetermined temperature. The back bezel is flattened upon a condition that the temperature is under the predetermined temperature. The predetermined temperature indicates to a threshold temperature of deformation of the memorizing alloy materials. The present invention also proposes an LCD device and an OLED display device. The backlight module, the LCD device and the OLED display device of the present invention are capable of switching a surface between a plane and a curve at will.