Light guide structure, direct type backlight module and display panel

A light guide structure, comprising:

• a first waveguide layer having a first light incident surface and a first light exiting surface;
• a polarization beam-splitting structure disposed on the first light exiting surface, and configured to split light emitted from a light source into first polarized light and second polarized light;
• a first polarization coupling grating disposed on the first light incident surface and configured to deflect the first polarized light and allow the first polarized light to be totally reflected in the first waveguide layer;
• a second waveguide layer having a second light incident surface and a second light exiting surface and disposed on the polarization beam-splitting structure;
• and
• a second polarization coupling grating disposed between the second light incident surface and the polarization beam-splitting structure and configured to deflect the second polarized light and allow the second polarized light to be totally reflected in the second waveguide layer.