Light emitting device and manufacturing method thereof, backlight module, display panel and display device

A manufacturing method of a light emitting device for display, comprising:

• providing a substrate;
• forming a circuit layer on a side of the substrate;
• providing at least one switching element and at least one light emitting element;
• and
• electrically connecting the switching element and the light emitting element to the circuit layer;
• wherein the circuit layer comprises a first power signal line, a second power signal line, and a pulse width modulation signal line;
• wherein the switching element comprises a control terminal, a first terminal and a second terminal;
• wherein the control terminal is electrically connected to the pulse width modulation signal line,
• wherein the first terminal is electrically connected to the first power signal line, and the second terminal is electrically connected to the second power signal line;
• wherein (i) the light emitting element is electrically connected to the first terminal and the first power signal line, or (ii) the light emitting element is electrically connected to the second terminal and the second power signal line;
• wherein the circuit layer comprises a binding layer away from the substrate;
• wherein electrically connecting the switching element and the light emitting element to the circuit layer comprises:
• binding and electrically connecting the switching element to the binding layer;
• and
• binding and electrically connecting the light emitting element to the binding layer;
• wherein the circuit layer further comprises a weld assisting layer, wherein the weld assisting layer is formed on one side of the binding layer facing away from the substrate;
• and
• wherein the manufacturing method further comprises:
• providing a resistor;
• and
• electrically connecting the resistor to the circuit layer, wherein the resistor and the light emitting element are electrically connected in series between the first power signal line and the second power signal line.