FIELD OF INVENTION

The present disclosure relates to the field of display technologies, and particularly relates to a large-sized and top-emitting organic light emitting diode (OLED) display panel and a manufacturing method of the display panel.

Background of Invention

Organic light-emitting diode (OLED) display devices mainly include a bottom-emitting type (emitting light downward from a substrate) and a top-emitting type (emitting the light upward relative to the substrate). Compared with bottom-emitting typed OLEDs, top-emitting typed OLEDs do not emit the light through the substrate, and the light is emitted from above devices, pixel circuit designs on the substrate do not affect a luminous area of the devices, thereby preventing competition between an area of thin film transistors (TFTs) and metal circuits and the luminous area, so an aperture ratio of panels can be effectively improved, and OLED display panels with high brightness and high resolution can be manufactured. Meanwhile, an operating voltage of top-emitting typed OLEDs is lower under a same brightness, so that a service life of the devices is longer and power consumption is lower.

Technical Problems

In top-emitting OLED display devices, because light needs to pass through a cathode of the devices, in order to ensure a luminous rate, a transparency of the cathode should be increased. In prior art, the cathode of the top-emitting OLED devices is generally made of low-power functional metal or alloy (such as Ag or magnesium silver alloy), or transparent conductive oxide (TCO, such as IZO). However, above two kinds of cathodes inevitably arise a problem of high cathode sheet resistance. By using metal or alloy as the cathode of the devices, in order to prevent an influence of the cathode on a light extraction rate, the cathode is made thinner; while using the transparent conductive oxide as the cathode of the devices, the cathode is not needed to make very thin due to high transparency of material itself.

For a large-sized and top-emitting OLED display panel, the cathode sheet resistance of the devices is too large, a voltage drop (IR-drop) of the panel is serious, the farther away from a power supply on the pane, the more serious the voltage drop may be, thereby resulting in a large difference in brightness between a periphery of the panel and a center of the panel and resulting in a serious uneven brightness phenomenon on the panel. In a position where the brightness of the panel is too large, a panel heating is too large, which is easy to affect a normal operation of a thin film transistor (TFT) substrate. Moreover, the cathode sheet resistance is too large, a driving voltage of OLED devices is large, and a power consumption of the panel is increased.

TECHNICAL SOLUTIONS

One of purposes of the present disclosure is to provide a display panel, by arranging an auxiliary cathode in a non-display area and by using a parallel connection of the auxiliary cathode and the cathode, the cathode resistance of the devices is reduced to relieve an IR-Drop phenomenon and improve a brightness uniformity of the panel.

The display panel includes: an array substrate including a display area and a non-display area; a first electrode disposed on the array substrate and corresponding to the display area; a pixel definition layer disposed on the array substrate and corresponding to the non-display area; an organic functional layer disposed on the first electrode and the pixel definition layer; a second electrode disposed on the organic functional layer; a covering layer disposed on the second electrode and corresponding to the display area; and an auxiliary electrode disposed on the second electrode and corresponding to the non-display area, wherein the auxiliary electrode is connected in parallel with the second electrode.

Furthermore, a material of the covering layer includes an organic material; and a material of the auxiliary electrode includes a metal material.

Furthermore, the organic functional layer includes: a light-emitting function layer disposed on the first electrode; and an electron transport layer disposed on the light-emitting function layer and the pixel definition layer.

Furthermore, the organic functional layer includes: a hole injection layer; a hole transport layer disposed on the hole injection layer; and a light-emitting layer disposed on the hole transport layer.

Furthermore, the pixel definition layer includes: a first layer, wherein edges of the first layer cover the first electrode; and a second layer disposed on the first layer.

Another purpose of the present disclosure is to provide a manufacturing method of the display panel, the organic material can be patterned to form a covering layer without using a fine mask, and the metal material can be patterned to form the auxiliary electrode by utilizing the characteristics of self-assembled materials, thereby reducing production costs.

The manufacturing method of a display panel includes: providing an array substrate and a mask, wherein the array substrate includes a display area and a non-display area, the mask includes a light transmitting area and a non-light transmitting area; forming a first electrode on the array substrate, wherein the first electrode corresponds to the display area; forming a pixel definition layer on the array substrate, wherein the pixel definition layer corresponds to the non-display area; forming an organic functional layer on the first electrode and the pixel definition layer; forming a second electrode on the organic functional layer; vacuum evaporating an organic material on the second electrode; setting the mask above the array substrate, wherein the light transmitting area corresponds to the non-display area, and the non-light transmitting area corresponds to the display area; irradiating the mask with a laser, wherein light is transmitted through the light transmitting area to the organic material in the non-display area, the organic material in the non-display area absorbs high energy to sublimate into a gaseous state, gaseous molecules are condensed into a film in the light transmitting area, and the organic material in the display area forms a covering layer; and forming an auxiliary electrode on the second electrode of the non-display area, wherein the auxiliary electrode is connected in parallel with the second electrode.

Furthermore, the step of forming the auxiliary electrode on the second electrode of the non-display area specifically includes: vacuum evaporating a metal material on the display area and the non-display area, wherein due to repulsion between the organic material in the display area and the metal material, the metal material spontaneously forms a film in the non-luminescent area to form the auxiliary electrode.

Furthermore, the mask includes: a light transmitting substrate including alignment marks; a masking layer disposed on the light transmitting substrate and corresponding to the non-light transmitting area; and a limiting frame arranged around the light transmitting substrate and surrounding the covering layer.

Furthermore, the step of setting the mask above the array substrate includes: making the alignment marks of the mask correspond to alignment marks of the array substrate, wherein a side of the masking layer faces the array substrate, and the limiting frame is arranged at a periphery of the array substrate.

Furthermore, in the step of forming the pixel definition layer on the array substrate of the non-display area, a double-layered pixel definition layer is manufactured by using two yellow light processes; and in a step of forming the organic functional layer on the first electrode and the pixel definition layer, the organic functional layer is manufactured by a method of inkjet printing.

BENEFICIAL EFFECTS

Beneficial effects of the present disclosure are: the present disclosure provides a display panel and a manufacturing method of the display panel. By arranging an auxiliary cathode in a non-display area and using a parallel connection of the auxiliary cathode and a cathode, a cathode resistance of devices is reduced to relieve an IR-drop phenomenon and improve a brightness uniformity of a panel. The present disclosure provides the manufacturing method of the display panel, the organic material can be patterned to form a covering layer without using a fine mask, and a metal material can be patterned to form the auxiliary electrode by utilizing characteristics of self-assembled materials, thereby reducing production costs.

