OLED display panel, manufacturing method thereof and display apparatus

An OLED display panel, comprising:

• a substrate, a light emitting structure layer and a viewing angle improving layer which are disposed on the substrate,
• wherein:
• the light emitting structure layer is configured to emit light to the viewing angle improving layer;
• the viewing angle improving layer is disposed on one side of the light emitting structure layer away from the substrate and is configured to adjust viewing angles of the display panel to allow a viewing angle of the display panel along a first direction to satisfy a first viewing angle range and to allow a viewing angle along a second direction to satisfy a second viewing angle range, and the first viewing angle range is smaller than the second viewing angle range;
• the first direction is perpendicular to the second direction;
• the viewing angle improving layer comprises:
• a first viewing angle improving layer and a second viewing angle improving layer;
• the first viewing angle improving layer is disposed on one side of the second viewing angle improving layer close to the substrate or the first viewing angle improving layer is disposed on one side of the second viewing angle improving layer away from the substrate;
• the first viewing angle improving layer is configured to adjust the viewing angle of the display panel along the first direction to allow the viewing angle of the display panel along the first direction to satisfy the first viewing angle range;
• the second viewing angle improving layer is configured to adjust the viewing angle of the display panel along the second direction to allow the viewing angle of the display panel along the second direction to satisfy the second viewing angle range;
• the light emitting structure layer comprises:
• a pixel define layer, a plurality of light emitting structures and an encapsulation layer;
• each light emitting structure comprises:
• a first electrode, an organic light emitting layer and a second electrode, the first electrode is disposed on a side of the organic light emitting layer close to the substrate and the second electrode is disposed on a side of the organic light emitting layer away from the substrate;
• the pixel define layer is provided with a plurality of opening regions, each of the opening regions forms an effective light emitting region corresponding to the light emitting structure, and second electrodes of adjacent light emitting structures are electrically connected with each other;
• the encapsulation layer is disposed on one side of the second electrodes away from the substrate;
• the second viewing angle improving layer comprises:
• a diffusion layer and a planarization layer, the planarization layer is disposed on one side of the diffusion layer away from the substrate;
• the diffusion layer is configured to diffuse light emitted from the light emitting structure layer, and a refractive index of the diffusion layer is larger than a refractive index of the planarization layer;
• an orthographic projection of the planarization layer on the substrate covers an orthographic projection of the diffusion layer on the substrate, and a transmittance of the planarization layer is greater than 90%;
• the diffusion layer comprises:
• a plurality of diffusion structures arranged along the second direction, and the diffusion structures have strip structures extending along the first direction;
• an orthographic projection of each diffusion structure on the substrate covers an orthographic projection of the organic light emitting layer included in the corresponding light emitting structure on the substrate;
• and
• a cross section of each diffusion structure extending along the second direction and perpendicular to a plane of the substrate is an isosceles trapezoid, an included angle between a leg and a bottom base of the isosceles trapezoid is greater than or equal to 20 degrees and less than or equal to 50 degrees.