CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. national phase of PCT Application No. PCT/CN2018/072084 filed on Jan. 10, 2018, which claims priority to Chinese Patent Application No. 201710524515.5 filed on Jun. 30, 2017, which are incorporated herein by reference in their entireties.

TECHNICAL FIELD

The present disclosure relates to the field of display technology, in particular to an organic light-emitting diode (OLED) display substrate, a manufacturing method thereof and a display device.

BACKGROUND

Layers of an OLED device include film layers such as an organic electroluminescence (OEL) layer, a transparent electrode and a substrate, and each of the film layers has a refractive index greater than air. Due to the existence of total reflection, merely parts of light beams from the OEL layer each having an incident angle at each interface in a given light-emitting direction that is smaller than a total reflection angle may exit from the OLED device directly. The light beams generated by a certain light-emitting point (or a secondary light source point) and passing through the interfaces of the film layers form a cone, i.e., an escaping cone. For the OLED device in a bottom-emission (BE) mode, the light beams within the escaping cone may exit from the OLED device directly. The light beams beyond the escaping cone may be totally reflected at different interfaces and then transmitted in the corresponding film layers in a wave guide mode. Usually, a proportion of the number of light beams transmitted in the wave guide mode to the total number of light beams is greater than the number of light beams capable of directly exiting from the OLED device to the total number of light beams. Hence, a luminous efficiency of the OLED device may be significantly adversely affected.

SUMMARY

An object of the present disclosure is to provide an OLED display substrate, a manufacturing method thereof, and a display device, so as to improve the luminous efficiency of the OLED display device.

In one aspect, the present disclosure provides in some embodiments an OLED display substrate, including a thin film transistor (TFT) array layer, a first electrode, a pixel definition layer, an OEL layer and a second electrode that are arranged on a base substrate. The pixel definition layer is configured to define a plurality of subpixel regions. A reflection structure is arranged to surround each of the subpixel regions, and is capable of reflecting light beams that are transmitted from the OEL layer and beyond an escaping cone, to enable at least parts of the reflected light beams to enter the escaping cone.

In a possible embodiment of the present disclosure, a groove surrounds each subpixel region, and the reflection structure is a reflection layer formed at a side wall of the groove.

In a possible embodiment of the present disclosure, the groove is formed in the pixel definition layer, and a depth of the groove is not greater than a thickness of the pixel definition layer.

In a possible embodiment of the present disclosure, the TFT array layer and the pixel definition layer surround each of the subpixel regions, the pixel definition layer is arranged on the TFT array layer, the groove is formed on a laminated structure consisting of the TFT array layer and the pixel definition layer surrounding each of the subpixel regions, and a depth of the groove is greater than a thickness of the pixel definition layer and not greater than a sum of the thickness of the pixel definition layer and a thickness of the TFT array layer.

In a possible embodiment of the present disclosure, the TFT array layer and the pixel definition layer surround each of the subpixel regions, the pixel definition layer is arranged on the TFT array layer, the groove is formed on a laminated structure consisting of the base substrate, the TFT array layer and the pixel definition layer surrounding each of the subpixel regions, and a depth of the groove is greater than a sum of a thickness of the TFT array layer and a thickness of the pixel definition layer, and smaller than a sum of the thickness of the pixel definition layer, the thickness of the TFT array layer and a thickness of the base substrate.

In a possible embodiment of the present disclosure, the first electrode is a transparent electrode, the second electrode is a reflective metal electrode, and the reflection layer is made of a same material as the second electrode.

In a possible embodiment of the present disclosure, the TFT array layer is provided with an opening surrounding each of subpixel regions, and a portion of the pixel definition layer is arranged in the opening.

In a possible embodiment of the present disclosure, the reflection layer comprises a first portion and a second portion, the first portion is angled relative to the TFT array layer at a first angle, the second portion is angled relative to the pixel definition layer at a second angle, and the first angle is different from the second angle.

In a possible embodiment of the present disclosure, the reflection layer is of a V-shaped or trapezoidal cross section, and the V-shaped or trapezoidal cross section is perpendicular to an extension direction of the reflection layer.

In another aspect, the present disclosure provides in some embodiments a display device including the above-mentioned display substrate.

In yet another aspect, the present disclosure provides in some embodiments a method for manufacturing an OLED display substrate, including: forming a TFT array layer, a first electrode, a pixel definition layer, an OEL layer and a second electrode sequentially on a base substrate, wherein the pixel definition layer is configured to define a plurality of subpixel regions; and forming a reflection structure surrounding each of the subpixel regions, wherein the reflection structure is capable of reflecting light beams that are transmitted from the OEL layer and beyond an escaping cone, to enable at least parts of the reflected light beams to enter the escaping cone.

In a possible embodiment of the present disclosure, the forming the TFT array layer includes: forming the TFT array layer that has an opening and surrounds each of the subpixel regions

In a possible embodiment of the present disclosure, the forming the reflection structure includes: forming a groove surrounding each of the subpixel regions, and forming a reflection layer on a side wall of the groove.

In a possible embodiment of the present disclosure, the forming the reflection layer includes: forming the second electrode and the reflection layer through a single process.

In a possible embodiment of the present disclosure, the forming the reflection layer includes: forming a first portion of the reflection layer and a second portion of the reflection layer, wherein the first portion is angled relative to the TFT array layer at a first angle, the second portion is angled relative to the pixel definition layer at a second angle, and the first angle is different from the second angle.

