Organic light-emitting diode display

The present application provides an organic light-emitting diode display. The display includes a plurality of pixel defining units, the pixel defining unit includes a first portion formed on a switch array layer which is not covered by anode electrodes and a second portion formed on the anode electrode, a groove is defined at the first portion, and at least one opening is defined at the second portion; an organic light-emitting layer including a plurality of organic light-emitting units, the organic light-emitting layer is formed on the anode electrodes which are not covered by the second portion.

BACKGROUND OF INVENTION

Field of Invention

The present application relates to a display technical field, and particularly to an organic light-emitting diode display.

Description of Prior Art

As organic light-emitting diodes (OLEDs) have advantages of autonomous light-emitting, a wide operating temperature range, a fast response, a wide vision, high light-emitting efficiency, being able to be produced on a flexible substrate, driving voltage, and low energy consumption, they are hailed to be as the next generation display technology.

However, because of technical difficulty factors and high cost of the existing OLEDs, it is difficult to realize mass production like liquid crystal displays (LCDs), and this results a huge gap in the market. At present, organic light-emitting diode (OLED) panels are mainly manufactured by evaporation processes, but applying the evaporation processes will reduce an utilization rate of material, and for large-sized panels, especially for OLED panels applying a Fine Metal Mask (FMM) technique that it is difficult to ensure uniformity of film thickness due to bending of the substrate.

Afterwards, the OLED panels are manufactured by inkjet printing technology. The inkjet printing technology is dissolving an OLED material in a solvent or dispersing the OLED material as nanometer droplets in a solvent, and then spraying the material onto a substrate surface through a nozzle and forming a film through a drying process. The inkjet printing technology has a high material utilization rate, a simple production process, and is easy to produce large panels. However, the inkjet printing technology needs to strictly control sizes of the droplets sprayed from the printing nozzle during the manufacturing process, and to ensure its uniformity, secondly, a volume of each light-emitting layer of inkjet printing ink must be consistent to ensure the uniformity of film thickness. In addition, during the printing process, it is necessary to ensure that the light-emitting layer inkjet printing ink is accurately sprayed on a corresponding light-emitting region, and cannot be sprayed on other light-emitting regions, otherwise to cause color mixing. It can be seen that the existing inkjet printing technology is prone to uneven film thickness and color mixing.

Therefore, it is necessary to provide an organic light-emitting diode display to solve the existing technological problems.

SUMMARY OF INVENTION

An object of the present application is to provide an organic light-emitting diode (OLED) display, so as to improve a uniformity of film thickness and reduce the color mixing.

For the above-mentioned objective, the present application provides an organic light-emitting diode (OLED) display, including:

a substrate base;

a switch array layer formed on the substrate base;

a first conductive layer formed on the switch array layer, wherein the first conductive layer comprises a plurality of anode electrodes spaced from each other;

a plurality of pixel defining units, wherein the pixel defining unit comprises a first portion and a second portion, the first portion is formed on the switch array layer which is not covered by the anode electrodes, the second portion is formed on the anode electrode and located at periphery of the anode electrode; wherein a groove is defined at the first portion, at least one opening is defined at the second portion; a width of the opening is less than a width of the second portion; material of the pixel defining unit comprises at least one of organic photoresist, silicon nitride, silicon oxide, and silicon dioxide; and

an organic light-emitting layer comprising a plurality of organic light-emitting units, wherein the organic light-emitting layer is formed on the anode electrodes which are not covered by the second portions.

The OLED display of the present application, the second portion includes a first sub layer and a second sub layer, the second sub layer is formed on the first sub layer, and the opening is defined at the second sub layer.

The OLED display of the present application, a height of the opening is the same as a thickness of the second sub layer.

The OLED display of the present application, the opening is connected to light-emitting region and the groove, the light-emitting region is a region that formed in the second portion and corresponding to the anode electrode.

The OLED display of the present application, a polarity of the material of the second sub layer is opposite to that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the second sub layer is greater than 45 degreess; a polarity of the material of the first sub layer is the same as that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the first sub layer ranges from 10 degrees to 45 degrees.

The OLED display of the present application, a top of the anode electrode is higher than a horizontal top of the groove, which the horizontal top is a top of a horizontal portion of the groove, and the groove includes horizontal portion and vertical portion.

The OLED display of the present application, a height of the opening is less than that of the second portion.

The OLED display of the present application, the pixel defining layer is a single layer structure, a polarity of the material of the first portion is the same as that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the first portion ranges from 10 degrees to 45 degrees; a polarity of the material of a top surface of the second portion is opposite to that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the top surface of the second portion is greater than 45 degrees.

The OLED display of the present application, a thickness of the second portion is set according to a volume of the light-emitting layer inkjet printing ink.

The present application provides an organic light-emitting diode (OLED) display, including:

a substrate base;

a switch array layer formed on the substrate base;

a first conductive layer formed on the switch array layer, wherein the first conductive layer comprises a plurality of anode electrodes spaced from each other;

a plurality of pixel defining units, wherein the pixel defining unit comprises a first portion and a second portion, the first portion is formed on the switch array layer which is not covered by the anode electrodes, the second portion is formed on the anode electrode and located at periphery of the anode electrode; wherein a groove is defined at the first portion, at least one opening is defined at the second portion; and

an organic light-emitting layer comprising a plurality of organic light-emitting units, wherein the organic light-emitting layer is formed on the anode electrodes which are not covered by the second portions.

The OLED display of the present application, the second portion includes a first sub layer and a second sub layer, the second sub layer is formed on the first sub layer, and the opening is formed on the second sub layer.

The OLED display of the present application, a height of the opening is the same as a thickness of the second sub layer.

The OLED display of the present application, the opening is connected to light-emitting region and the groove, the light-emitting region is a region that formed in the second portion and corresponds to the anode electrode.

The OLED display of the present application, a polarity of the material of the second sub layer is opposite to that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the second sub layer is greater than 45 degrees; a polarity of the material of the first sub layer is the same as that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the first sub layer ranges from 10 degrees to 45 degrees.

The OLED display of the present application, a top of the anode electrode is higher than a horizontal top of the groove, which the horizontal top is a top of a horizontal portion of the groove, and the groove includes horizontal portion and vertical portion.

The OLED display of the present application, a height of the opening is less than that of the second portion.

The OLED display of the present application, a width of the opening is less than that of the second portion.

The OLED display of the present application, the pixel defining unit is a single layer structure, wherein a polarity of the material of the first portion is the same as that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the first portion ranges from 10 degrees to 45 degrees; a polarity of the material of a top surface of the second portion is opposite to that of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the top surface of the second portion is greater than 45 degrees.

The OLED display of the present application, wherein a thickness of the second portion is set according to a volume of the light-emitting layer inkjet printing ink.

The OLED display of the present application, wherein a thickness of the pixel defining unit ranges from 0.5 um-10 um.

An OLED display of the present application provides openings and grooves on the pixel defining units, therefore, when the nozzle is deflected, the ink printed by mistake will be sprayed into the grooves, so as to prevent the light-emitting layer inkjet printing ink from spraying into other light-emitting regions during the printing process, and to avoid color mixing; in addition, when volume of the ink is larger, an excess of light-emitting layer inkjet printing ink will flow from the openings to the grooves, thus improving a uniformity of the film thickness.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The description of following embodiment, with reference to the accompanying drawings, is used to exemplify specific embodiments which may be carried out in the present disclosure. Directional terms mentioned in the present disclosure, such as “top”, “bottom”, “front”, “back”, “left”, “right”, “inside”, “outside”, “side”, etc., are only used with reference to the orientation of the accompanying drawings. Therefore, the used directional terms are intended to illustrate, but not to limit, the present disclosure. In the drawings, the components having similar structures are denoted by same numerals.

Referring toFIG. 1toFIG. 6,FIG. 1is a schematic view of an organic light-emitting diode (OLED) display of the present application.

The OLED display of the present application includes a substrate base11, a switch array layer12, a first conductive layer, a plurality of pixel defining units14, and an organic light-emitting layer15.

The switch array layer12is formed on the substrate base11, the switch array layer12can include a plurality of switch components, for example, the switch component is a thin film transistor.

The first conductive layer is formed on the switch array layer12, the first conductive layer includes a plurality of anode electrodes13spaced from each other.

The pixel defining unit14is located between two adjacent anode electrodes, the pixel defining unit14includes a first portion141and a second portion142, the first portion141is formed on the switch array layer12which is not covered by the anode electrode, that is, the first portion includes a portion that is horizontally located on the switch array layer12and a portion that is vertically located on the switch array layer12, a shape of the first portion is a U shape. Referring toFIG. 2, the second portion142is formed on the anode electrode13and is located around a periphery of the anode electrode13, that the second portion142is located around the periphery of the anode electrode13. The second portion142is limited to the anode electrode13to define a light-emitting region, that the light-emitting region is a region that is located in the second portion142and corresponds to the anode electrode, or the light-emitting region is located on the second portion142which is not covered by the anode electrode13, and a height of the light-emitting region is less than a height of the second portion142(that is, a region located at an inner rectangle inFIG. 2).

The first portion141defines a groove22, and the groove22includes a horizontal portion and a vertical portion. A top of the anode electrode13is greater than a horizontal top of the groove22, the horizontal top is a top of a horizontal portion of the groove22, that is, the groove22includes two side walls and a bottom, and the horizontal top is a top surface of the groove22.

The second portion142defines openings21; a height H2of the opening is less than a height of the second portion142, a height of the second portion142is H2plus H1.

The opening21is configured to connect between the light-emitting region and the groove22, the light-emitting region is a region that is formed in the second portion142and corresponds to the anode electrode. Although there are four openings21that are formed in the second portion142of theFIG. 2, the present application is not limited to provide one or more openings. The opening21can be formed at an arbitrary position of the second portion142. A width of the opening21is less than a width of the second portion142, in one embodiment, a cross-section shape of the second portion142is a quadrangle, an opening21is formed on at least one side of the second portion142, a width of an opening21located on one side of the second portion142is less than a width of the corresponding side of the second portion142. For example, a width L of an opening21located on one side of the second portion142is less than a width W of one side of the second portion142. Of course, it is understandable that the cross-section shape of the second portion142can also be a round or other shapes.

A length L of an opening21located on one side of the second portion142is equal to or less than a length of the corresponding side of the second portion142. A width of an opening21located on one side of the second portion142is less than a length of a side of the second portion142.

In one embodiment, a height of an inner side of the opening21is less than a height of an outer side of the opening21. The outer side of the opening21is close to the groove22, and the inner side of an opening21is far away from the groove22.

Material of the pixel defining unit14can be made of an organic material or a inorganic material, and includes at least one of organic photoresist, silicon nitride, silicon oxide, and silicon dioxide.

In order to make more uniform of a film thickness of the organic light-emitting layer, a thickness of the second portion142is set according to a volume of the light-emitting layer inkjet printing ink. A thickness of the second portion142is correlated to a volume of the light-emitting layer inkjet printing ink, a top of the light-emitting layer inkjet printing ink in the light-emitting region is higher than a thickness of the second portion142, but not more than 50% of the thickness of the second portion142. The ink that in excess of the second portion142flows into the groove22through the opening21.

Further, a thickness of the pixel defining unit ranges from 0.5 um-10 um.

In one embodiment, referring toFIG. 3, the pixel defining unit14is a single layer structure. Both of the first portion141and the second portion142are single layer structures.

Referring toFIG. 4, a polarity of the material of the first portion141is the same as a polarity of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the first portion ranges from 10 degrees to 45 degrees; a polarity of the material of a top surface of the second portion142is opposite to a polarity of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the top surface of the second portion is greater than 45 degrees. It is understandable that a contact angle between the side wall of the second portion142and the light-emitting layer inkjet printing ink ranges from 10 degrees to 45 degrees.

The organic light-emitting layer15is formed on the anode electrode13which is not covered by the second portion142, and the organic light-emitting layer15is formed by spraying printing the light-emitting layer inkjet printing ink24on the anode electrode13which is not covered by the second portion142. Specifically, the light-emitting layer inkjet printing ink24is sprayed by a nozzle23, and the light-emitting layer inkjet printing ink24is made by dissolving the OLED material in a solvent or dispersing the OLED material in a solvent as nanometer droplets.

In the detail process, after finishing a process of forming the anode electrode13, the pixel defining unit material is coated on the surface of the anode electrode, and the pixel defining unit14is cured and formed, a polarity of the material of the pixel defining unit14is the same as a polarity of the light-emitting layer inkjet printing ink24, a contact angle between the light-emitting layer inkjet printing ink24and the pixel defining unit ranges from 10 to 45 degrees, so as to improve the uniformity of the film thickness in the organic light-emitting layer. That is, a polarity of the material of the first portion is the same as a polarity of the light-emitting layer inkjet printing ink, a contact angle between the light-emitting layer inkjet printing ink and the first portion141ranges from 10 degrees to 45 degrees;

And then, an upper surface of the second portion142is treated to obtain a surface with an opposite polarity of the material of the light-emitting layer inkjet printing ink24, and a contact angle between the light-emitting layer inkjet printing ink24and the upper surface of the second portion142is greater than 45 degrees. That is, a polarity of the material of the upper surface of the second portion142is opposite to a polarity of the light-emitting layer inkjet printing ink, and the contact angle between the light-emitting layer inkjet printing ink and the upper surface of the second portion is greater than 45 degrees.

The anode electrode13which is not covered by the second portion142is exposed and developed to form the light-emitting region. A region that needs to form the groove in the pixel defining unit14located on the switch array layer12is exposed and developed to obtain the groove22. A region that needs to form the openings21on the second portion142is exposed and developed to obtain the openings21.

Referring toFIG. 4, when the nozzle23prints the light-emitting layer inkjet printing ink24on the light-emitting region of the above base, if a height of the light-emitting layer inkjet printing ink24located on the light-emitting region is higher than a height of the opening21of the second portion142, an excess of the light-emitting layer inkjet printing ink24flows into the groove22. Then the light-emitting layer inkjet printing ink24is baked to form a film, and further the organic light-emitting layer15is formed by a film layer printing process or vacuum coating process.

In another embodiment, referring toFIG. 5, a portion of the pixel defining unit14is a double layer structure, and that is, the second portion142is a double layer structure. The second portion142includes a first sub layer31and a second sub layer32, the second sub layer32is formed on the first sub layer31, and the openings21are formed on the second sub layer32.

Preferably, in order to simplify the production process and reduce the production cost, a height of the opening21is the same as a thickness of the second sub layer32.

In one embodiment, in order to improve the film thickness uniformity of the organic light-emitting layer, a height of the inner side of the opening21is less than a height of the outer side of the opening21. The outer side of the opening21is close to the groove22, and the inner side of the opening21is far away from the groove22.

In the specific process, after finishing the process of forming the anode electrode13, a material of the first sub layer31is coated on a surface of the base containing the anode electrode, and cured to form the first sub layer31, the polarity of the material of the first sub layer31is the same as the polarity of the inkjet printing ink24of the light-emitting layer, a contact angle between the inkjet printing ink24of the light-emitting layer and the first sub layer31ranges from 10 to 45 degrees.

The anode electrode13which is not covered by the second portion142is exposed and developed to form the light-emitting region. The region that needs to form a groove in the first sub layer31located on the switch array layer12is exposed and developed to obtain the groove22.

A material of the second sub layer32is coated on the surface of the base, and cured, exposed, and developed to form the second sub layer32, and then a region that needs to form the opening on the second sub layer32is exposed and developed to obtain the opening22. Depending on the photoresist used, the time of exposing and developing is different. The polarity of the material of the second sub layer32is opposite to the polarity of the inkjet printing ink24of the light-emitting layer, a contact angle between the light-emitting layer inkjet printing ink24and the second sub layer32is greater than 45 degrees.

During the process of printing, there may be a difference in the volume of ink ejected from the nozzle, and the ink volume in each light-emitting region between the whole panel and the substrate is different to make uneven film thicknesses and affect the light-emitting uniformity, so the present application accurately calculates the height of the opening21according to concentration of the ink, and during the printing process, the planned volume of the ink is more than the actual required volume of the ink, the excess of ink flows into the groove22through the openings21, so finally the amount of each light-emitting region is correlated to the height of the openings, that is, the heights of the openings of each pixel defining unit are same to make the thicknesses of the light-emitting layer to be the same.

As the first portion141provides a groove22, so the excess of ink in the light-emitting region flows into the groove22, when the amount of ink in the each light-emitting region is more, the excess of the ink flows into the groove22through the opening21on the second portion by controlling the height of the groove22, that is the remain amount of ink in each light-emitting is correlated to the height of opening on the second portion, so the height of the opening is controlled to ensure the uniformity of the organic light-emitting film thickness.

Referring toFIG. 6, when the nozzle23prints the light-emitting layer inkjet printing ink24on the light-emitting region of the above base, if a height of the light-emitting layer inkjet printing ink24located on the light-emitting region is higher than a height of the opening21of the second portion142, an excess of the light-emitting layer inkjet printing ink24flows into the groove22through the openings21. Then the light-emitting layer inkjet printing ink24is baked to form a film, and further the organic light-emitting layer15is formed by a film layer printing process or vacuum coating process.

Referring toFIG. 6, when the location of the nozzle23is deflecting during the OLED printing process, on the one hand, the light-emitting layer inkjet printing ink24(hereinafter referred to as ink) with error printing will be printed into the groove22to avoid color mixing; on the other hand, the ink24printed on the second portion142flows into the groove, and does not flow to the light-emitting region of other corresponding colors, so as to avoid color mixing. And more, the excess amount of the ink flows into the groove through the opening on the second portion when too much ink is printed on the light-emitting region, and so as to avoid the uneven film thickness of the organic light-emitting layer caused by volume of the ink droplets is different.

An OLED display of the present application provides openings and grooves on the pixel defining units, therefore, when the nozzle is deflected, the ink printed by mistake will be sprayed into the grooves, so as to prevent the light-emitting layer inkjet printing ink from spraying into other light-emitting regions during the printing process, and to avoid color mixing; in addition, when volume of the ink is larger, an excess of light-emitting layer inkjet printing ink will flow from the openings to the grooves, thus improving a uniformity of the film thickness.

The above embodiment does not constitute a limitation of the scope of protection of the present technology solution. Any modifications, equivalent replacements and improvements based on the spirit and principles of the above embodiments should also be included in the protection scope of the present technology solution.