CN113161400A

CN113161400A - CPL structure for improving Micro OLED microcavity effect and preparation method thereof

Info

Publication number: CN113161400A
Application number: CN202110432943.1A
Authority: CN
Inventors: 许嵩; 刘胜芳; 赵铮涛
Original assignee: Semiconductor Integrated Display Technology Co Ltd
Current assignee: Semiconductor Integrated Display Technology Co Ltd
Priority date: 2021-04-22
Filing date: 2021-04-22
Publication date: 2021-07-23

Abstract

The invention provides a CPL structure for improving Micro OLED microcavity effect and a preparation method thereof, wherein a first capping layer is prepared on an OLED; preparing a plurality of protruding parts arranged at intervals on the first covering layer through ink-jet printing to form scattering particles so as to effectively reduce the influence of the microcavity on the OLED device and improve the WOLED color drift phenomenon; the full-color silicon-based OLED display device structure meets the product requirements.

Description

CPL structure for improving Micro OLED microcavity effect and preparation method thereof

Technical Field

The invention belongs to the field of Micro OLED display, and particularly relates to a CPL structure for improving Micro OLED microcavity effect and a preparation method thereof.

Background

Compared with the traditional AMOLED display technology, the silicon-based OLED micro-display takes the monocrystalline silicon chip as the substrate, and the pixel size is smaller and the integration level is higher by means of the mature CMOS process, so that the silicon-based OLED micro-display can be manufactured into a near-to-eye display product which is comparable to large-screen display and is widely concerned. Based on the technical advantages and wide market, in the fields of military and consumer electronics, the silicon-based OLED micro-display will raise the new wave of near-to-eye display, and bring unprecedented visual experience for users.

Limited by the manufacturing technology of metal mask, the existing full-color products of high ppi silicon-based OLEDs mostly adopt the WOLED (white OLED) plus CF (color filter) technology, and in order to realize color display, the spectrum of the WOLED usually includes 3 peaks of RGB. Since the light of three RGB colors corresponds to optical micro-cavities with different thicknesses, the WOLED with the top emission structure with a single optical thickness is prone to color shift, as shown in fig. 1 and fig. 2.

Currently, the silicon-based OLED industry generally uses an evaporation method to form the CPL layer. Because the CPL layer is thin and has little water-oxygen barrier, it cannot be patterned using conventional photolithographic techniques.

Disclosure of Invention

The invention provides a CPL structure for improving Micro OLED microcavity effect, wherein a lug boss sealing layer CPL layer is arranged between an OLED layer and a TFE layer at intervals to form scattering ions and reduce the microcavity effect on an OLED.

The invention also aims to provide a preparation method of the CPL structure for improving the Micro OLED microcavity effect, which is characterized in that the interval printing convex parts are printed by an IJP ink-jet printing mode without damaging the OLED to form scattering particles so as to effectively reduce the influence of the microcavity on an OLED device and improve the WOLED color drift phenomenon.

The specific technical scheme of the invention is as follows:

a CPL structure for improving Micro OLED microcavity effect comprises an OLED layer, wherein a first covering layer is arranged on the OLED layer; the first sealing cover layer is provided with a plurality of convex parts which are arranged at intervals.

The thickness of the first sealing cover layer is 190-220 nm; preferably 200 nm;

the height of the convex part is 80-310nm, preferably 100 nm;

the first sealing layer and the plurality of protrusions which are arranged at intervals form a sealing layer, namely a CPL structure; the total thickness of the sealing layer is controlled to be 300nm-500 nm;

the first cover sealing layer is made of a high-transmittance material, preferably a polyethylacrylate material;

the bulge material is a low-transmittance material, and is preferably a PVC material.

A thin film packaging layer, namely a TFE layer, is arranged on the convex part;

and a color filter, namely a CF layer, is arranged on the thin film packaging layer.

The preparation method of the CPL structure for improving the Micro OLED microcavity effect provided by the invention comprises the following steps:

1) preparing a first capping layer on the OLED;

2) preparing a plurality of raised parts arranged at intervals on the first sealing cover layer through ink-jet printing;

step 1) specifically adopting ink-jet printing equipment or using a first covering layer in a common evaporation way in the industry; the thickness of the first sealing cover layer is 190-220 nm; preferably 200 nm; the first cover sealing layer is made of a high-transmittance material, preferably a polyethylacrylate material;

in the step 2), the convex part is cylindrical, and the height-to-width ratio of the cylindrical column is more than 1; the larger the number of columns, the better the scattering effect. In combination with IJP device capabilities, the cylindrical diameter is 50nm to 100nm, preferably 75 nm; the height of the cylinder is 80-310nm, preferably 100 nm; in the step 2), the plurality of convex parts are arranged at intervals, and the interval distance is 100nm-150 nm; the intervals are uniform.

In the step 2), the material of the bulge part is a low-transmittance material, preferably a PVC material;

the first sealing layer and the plurality of convex parts arranged at intervals form a sealing layer together, and the total thickness of the sealing layer is controlled to be 300nm-500 nm; preferably 300 nm.

In the preparation processes of the step 1) and the step 2), a cavity atmosphere with the concentration lower than 1ppm of water and 1ppm of oxygen is formed through a purifier; so as to prevent the bottom light-emitting layer (OLED layer) from contacting water and oxygen to lose efficacy.

The preparation method of the OLED structure comprises the following steps:

A. preparing a CMOS circuit on a silicon substrate;

B. preparing an anode layer on the CMOS circuit;

C. evaporating and plating all functional layers of the OLED on the anode layer in an evaporation mode;

after the step 2), preparing a thin film packaging layer on the sealing layer by using PECVD/ALD according to a process mature in the industry;

and finally, depositing a color filter on the thin film packaging layer according to a mature process in the industry.

According to the invention, materials with different transmittances are selected to form a CPL layer with reduced refractive index, so that the microcavity effect is reduced; light perpendicular to the CPL layer can be transmitted out through the CPL, and with the reduction of the angle, light rays at other angles are reflected or reduced by the opaque convex parts, so that the microcavity effect can be effectively reduced. The full-color silicon-based OLED display device and the full-color silicon-based OLED display method meet the requirements of high-brightness products.

Compared with the prior art, the full-color silicon-based OLED display device structure has the advantages that the CPL layer structure (between the OLED layer and the TFE layer) with the columnar interval is formed in an ink-jet printing mode, the light-emitting layer at the bottom layer of the OLED is not damaged, the microcavity effect is effectively improved, the white light color drift phenomenon of the Mirro OLED can be effectively reduced, and the product requirements are met.

Drawings

FIG. 1 is a silicon-based OLED full-color structure;

FIG. 2 is a graph of a WOLED spectrum;

FIG. 3 is a schematic structural view of CPL for improving Micro OLED Micro chamber effect according to the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Test materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

The specific techniques or conditions not specified in the examples can be performed according to the techniques or conditions described in the literature in the field or according to the product specification.

Example 1

the height of the convex part is 80-310nm, preferably 100 nm;

Example 2

A preparation method of a CPL structure for improving Micro OLED microcavity effect comprises the following steps:

1) preparing a CMOS circuit on a silicon substrate; preparing an anode layer on the CMOS circuit; evaporating and plating all functional layers of the OLED on the anode layer in an evaporation mode;

preparing a first capping layer on the OLED by using an evaporation method commonly used in the industry; the thickness of the first cover layer is 200 nm; preparing a polyethylacrylate material;

2) preparing a plurality of raised parts arranged at intervals on the first sealing cover layer through ink-jet printing; the bulge is made of PVC material and is cylindrical, and the diameter of the cylinder is 75nm in combination with the capability of IJP equipment; the height of the cylinder is 100 nm; in ink jet printing, several rows and columns of cylinders are printed, two cylinders per row being spaced apart by a distance of 100nm and two cylinders per column being spaced apart by a distance of 100 nm.

3) Preparing a thin film encapsulation layer on the capping layer by using PECVD/ALD according to a process mature in the industry;

4) the color filters are deposited on the thin film encapsulation layer according to well-established processes in the industry.

During the preparation process, a cavity atmosphere with the concentration lower than 1ppm of water and 1ppm of oxygen is formed through a purifier.

Claims

1. A CPL structure for improving Micro OLED microcavity effect is characterized by comprising an OLED layer, wherein a first capping layer is arranged on the OLED layer; the first sealing cover layer is provided with a plurality of convex parts which are arranged at intervals.

2. The CPL structure for improving the Micro OLED Micro-chamber effect as claimed in claim 1, wherein the thickness of the first capping layer is 190-220 nm.

3. A CPL structure for improving Micro OLED microchamber effect according to claim 1 or 2, wherein said protrusions have a height of 80-310 nm.

4. The CPL structure for improving the Micro OLED microchamber effect as claimed in claim 1, wherein the high transmittance material.

5. The CPL structure for improving the Micro OLED microchamber effect as claimed in claim 1, wherein the bump material is a low transmittance material.

6. A method for preparing a CPL structure for improving the Micro OLED Micro chamber effect as claimed in any one of claims 1 to 5, wherein the method comprises the following steps:

1) preparing a first capping layer on the OLED;

2) preparing a plurality of raised parts arranged at intervals on the first covering layer through ink-jet printing.

7. The method according to claim 6, wherein in step 2), the protrusions are cylindrical, and the cylindrical columnar aspect ratio > 1.

8. The method of claim 7, wherein the cylindrical shape has a diameter of 50nm to 100 nm.

9. The method for preparing a porous ceramic material according to claim 7 or 8, wherein the plurality of protrusions are spaced apart by a distance of 100nm to 150 nm; the intervals are uniform.

10. The method according to claim 7 or 8, wherein a chamber atmosphere of <1ppm below water and <1ppm below oxygen is formed by a purifier during the preparation.