JP2002299055A - Pixel structure of full color oled display element and method of manufacturing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pixel structure of a full color OLED display element, and to provide its manufacturing process. SOLUTION: This pixel structure of the full color OLED display element includes a black matrix by one piece, a color-changing medium(CCM) area by one piece, thin-film transistors by two pieces, a storage capacitor by one pieces, and an OLED element structure by one piece connected onto a base board. This manufacturing process of the full-color OLED display element pixel structure includes processes: (a) a black matrix manufacturing process, (b) a polysilicon island forming process, (c) a gate forming process, (d) an interlayer forming process, (e) a CCM process, and (f) an OLED implant (OLED deposition) process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light-emitting diode (OLED) display element, and more particularly to a pixel structure and manufacturing process of a full-color OLED display element.
s).

[0002]

2. Description of the Related Art Flat panel displays
l display) is one of the most important electronic application products at present, such as televisions, instrument display screens, and notebook computer display screens.
Organic electroluminescent (OE)
L) The display element has a light emitting
g), high luminance, wide viewin
g angle), fast response speed, high reliability, full color, low voltage drive (l
ow voltage driving), low power consumption and simple process.

[0003] This type of product is undoubtedly the best choice for next generation flat panel displays. Current,
There are many types of manufacturing methods and structures for full color organic light emitting display elements. For example, from (a) below
(e).

(A) In a low-molecular-weight system, a three-primary-color pixel array of red, green, and blue (RGB) light is obtained using a transmission precision optical mask.

(B) A white light OEL element is mainly used, and three primary colors of light are obtained through a color filter.

(C) Blue or purple OEL elements are mainly used, and the original blue light and purple light are converted to light of another color through the light conversion layer.

(D) Dielectric stack layers having different thicknesses are manufactured, and the original broadband light spectrum is converted into RGB primary colors by using the principle of physical reflection and interference of light.

(E) Based on an OEL element that transmits light on both sides, elements of three primary colors of RGB light are stacked on the same pixel.

US Pat. No. 5,550,066 discloses an organic electroluminescent (OE) device for thin film transistors (TFTs).
L) Describes a method for manufacturing a pixel structure of an element.
FIG. 1 is a schematic plan view of an OEL element of a thin film transistor.
(plan view). As shown in FIG. 1, the OEL element 100 of the thin film transistor mainly includes two thin film transistors 101 and 102 and one storage capacitor.
citor) 103 and a self-luminous OEL pad (light
emitting organic EL pad) 104. The thin film transistor 101 connects a source bus 105 to a data line (dat
a line) and the gate bus 106
(gate line). Ground bus 1
07 is below the gate bus and storage capacitor. The source electrode of the thin film transistor 101 (source electro
de) is electrically connected to the source bus. The gate electrode of the thin film transistor 101 includes a part of a gate bus. The self-luminous OEL pad 104 and the drain electrode of the thin film transistor 102 are electrically connected. The drain electrode of the thin film transistor 101 and the thin film transistor 102
Are electrically connected. The gate electrode and the storage capacitor 103 are electrically connected. The OEL element of the thin film transistor is basically composed of several pixel units forming a flat panel display.

FIG. 2 is a schematic sectional view of an OEL element 200 of a thin film transistor described in this patent document. As shown in FIG. 2, a polysilicon island (polysilicon islan
d) Implant 208 on the upper back of insulating substrate 201. Furthermore, the first gate insulating layer (gate insu
(lating layer) 202. A polysilicon gate (poly-si gate) layer 204 is implanted on the gate insulating layer 202. Ion implantatio
After n), a source electrode and a drain electrode area are formed in the gate insulating layer 202. Ion implantation
It conducts electricity with N-type impurities (dopant). The gate bus 206 is formed on the insulating layer 202, covers the second insulating layer 212 on the surface of the light emitting element, makes two contact holes in the insulating layer 212, and connects the thin film transistor with the thin film transistor using an electrode material. To form electrical conduction. The electrode material attached to the thin film transistor 102 is the top electrode of the storage capacitor 103 at the same time.
(topelectrode) 222 is formed. A source bus and a ground bus are also formed on the second insulating layer 212. The top electrode 222 contacts the drain electrode of the thin film transistor 102 and becomes an anode electrode layer 226 of OEL material. Next, a passivating layer of insulating material (passivating
layer) 224 is implanted. OEL to be used by installing a tapered edge for this isolation layer
It enhances the adhesion between the layer 232. OEL layer 232 is isolated layer 2
Implant above 24 and anode layer 226. Finally, the cathode electrode layer (cathode electrode layer) is again placed on the surface of the OEL element.
layer) 234 is implanted to form the OEL element 200.

In the current development situation, full-color OEL
There are still some issues that must be overcome for display elements to defeat the flat panel display market. For example, it is not easy to create a display element having high resolution, high luminous efficiency, and wide viewing angle. The luminance and luminous efficiency of OEL elements made of low-molecular materials tend to be insufficient. Although an OEL element made of a polymer material has three primary colors of RGB light, the overall luminance and luminous efficiency are still inferior to those of an OEL element made of a low molecular material. Furthermore, the materials used by OEL elements are incompatible with traditional yellow light manufacturing processes. Therefore, it is essential to develop an effective and simple process and structure of a full-color organic light-emitting element.

[0012]

SUMMARY OF THE INVENTION The present invention overcomes the shortcomings of known organic light emitting diode (OLED) displays. The present invention is a kind of full color OLED
One of the important purposes is to provide a pixel structure of a display element. It is another object of the present invention to provide a manufacturing process for a full color OLED display element pixel structure.

[0013]

Means for Solving the Problems The present inventors have made intensive studies to achieve the above object, and as a result, have reached the present invention. The pixel structure of the full-color OLED display element provided by the present invention includes a black matrix (black matrix).
matrix), one color changing medium (C
CM) One area, two thin film transistors, one storage capacitor, and one OLED element structure connected on the substrate.

The process for manufacturing a full color OLED display element pixel structure provided by the present invention includes the following steps:
(a) black matrix manufacturing process, (b) polysilicon island forming process, (c) gate forming process,
(d) an interlayer forming process, (e) a CCM process, and (f) an OLED implant process.

According to the invention, the pixel structure of the OLED display element is a blue OLED or a polymer LED.
Is a light emitting material. Low temperature polysilicon
(poly Si, LTPS) A thin film transistor supplies current to the OLED display element, and the active drive (a
ctive driving) element. The CCM converts blue light into red light or green light to form a full color LED. C
By using the same process for CM and LTPS thin film transistors, it is possible to manufacture display elements with high resolution, high energy efficiency, and a wide viewing angle.

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
The present invention will be described in detail, but they do not limit the present invention.

FIG. 3 shows a full-color organic light emitting diode according to the present invention.
Schematic of the electrical circuit of the Iode (OLED) display element
FIG. This full color OLED display element
Each pixel structure 300 has two thin film transistors T₁And T₂,
Storage capacitor C_s1 piece, OLED element structure 1 piece
including. Thin film transistor T₁And T₂Are below,
Including a source electrode, a drain electrode, and a gate electrode. Thin film
Lanista T₁Gate electrode is part of gate line 301
including. Thin film transistor T₁Source electrode is
It is electrically connected to the IN 302. Also the thin film transistor T₁
Drain electrode and thin film transistor T₂The gate electrode of
Connect with electricity. Thin film transistor T ₂Gate power
The pole is the storage capacitor C_sAnd connected by electricity
You. OLED element is thin film transistor T₂Drain of
It is electrically connected to the electrodes.

FIG. 4 is a schematic plan view of a full color OLED display element according to the present invention. According to FIG.
Thin film transistor T ₂ and the OLED element series (in serie
s) and is, also the storage capacitor C _s and the thin film transistor T ₁ are in series. OLED elements are connected on one insulating substrate (not shown in this table). The black box 403 is formed on the insulating substrate. Thin film transistor T ₁ is data bus line (data bus
line) 405 to data line, gate bus line (gate busl)
ine) 406 as a gate line, and Vdd bus line 407 as a power supply bus.

In this embodiment, an LTPS thin film transistor is used.
The current is supplied to the OLED element, and the LTPS thin film transistor is used as the active drive element. The OLED element uses a blue OLED or a polymer LED as a light emitting material.

FIGS. 5 to 12 are schematic views of the cross-sectional structure along the line BB 'in FIG. FIG. 13 is a schematic diagram of a cross-sectional structure along the line AA ′ in FIG.

As described above, the pixel structure process of the full-color OLED display element of the present invention mainly includes a black matrix forming process, a polysilicon island forming process, a gate forming process, an intermediate layer forming process, a CCM forming process, and an OLED implant process. Including.

According to the present invention, the CCM and the LTPS thin film transistor are formed in the same process, and in the CCM process,
Full color LED by converting blue light to red light or green light
To form This makes it possible to produce display elements with high resolution, high efficiency and a wide viewing angle.

The following is a cross-sectional view along the line BB ',
The procedure of each process of the full-color OLED display element of the present invention will be described with reference to FIGS.

FIG. 5 is a schematic view of a cross-sectional structure along the line BB ', and illustrates the first step of the present invention, that is, the procedure of a black matrix forming process. In this process, first, an insulating substrate 501 is prepared. The insulating substrate has a top layer surface and a bottom layer surface. The black matrix 502 is implanted on the surface of the top layer of the insulating substrate, and this is determined. In addition, a buffer layer 504 is implanted on the plaque matrix 502.

FIG. 6 is a schematic view of a cross-sectional structure along the line BB ', and illustrates a second step of the present invention, that is, a procedure of a polysilicon island forming process. In this process, first, a polysilicon layer 6 is formed on the buffer layer 504.
02 and the implant to form the source electrode and the drain electrode area of the source electrode and the drain electrode and T ₂ of the thin film transistor T _1. Finally, as shown in FIG. 6, a polycrystalline silicon island is defined and formed using a laser crystal method and an etching method.

The source electrode and the drain electrode area of the thin film transistor T ₁ is in this embodiment, formed after the ion implant, electrically conductive by inserting the N ⁺ -type impurity 604 at the top of the buffer layer 504. P The source electrode and a drain electrode area of the thin film transistor T ₂ are at the top of the buffer衝層504
Conductivity is provided by the ⁺ type impurity 606.

FIG. 7 is a schematic view of a cross-sectional structure along the line BB 'in FIG. 4, and illustrates a third step of the present invention, that is, a procedure of a gate forming process. In this process,
A gate material is formed by implanting a conductive material on top of the polysilicon island. In this embodiment, first, a gate oxide (gate oxide) 60 is formed on the polysilicon island.
Implant 8 and gate metal 706 respectively. Next, the gate layer is determined.
Determination of T ₁ gate electrode 702 of the T ₂ and 704 also include.

FIG. 8 is a schematic view of the cross-sectional structure along the line BB 'in FIG. 4, illustrating the fourth step of the present invention, the procedure of the intermediate layer forming process. In this process, first, the intermediate layer 802 is implanted again above the gate layer and the heavy polysilicon island. Thereby, the source electrode and the drain electrode are implanted and formed, and the metal area of the source electrode and the drain electrode is formed.

FIGS. 9 to 11 are schematic views of the cross-sectional structure along the line BB '.
Describes the steps of the CCM process. CCM according to the present invention
And LTPS thin film transistor unify this process. In this process, the isolation layer 902 is first deposited on the intermediate layer 802, and then the CCM is formed. The process of CCM formation includes the following three consecutive steps. (a) Etch isolation layer
(passivation etching) to form the CCM area 904 and a part of the electrode layer contact area. The results are shown in FIG.
(b) Spin coating the CCM area 904
Repeat the general photolithography technology (ph
Individual CCM pattern of red, green and blue pixels (discrete R, G, and B pixels) using otolithography technique
(pattern). FIG. 10 shows the results after the spin coating and the exposure and development of general photolithography were repeated three times. (c) a transparent conductive material layer, such as indium tin oxide, on top of the display element
(indium tin oxide, ITO) 906 etc.
er) to form the transparent conductive material layer. Figure 1 shows the results.
It is shown in FIG.

FIG. 12 is a schematic view of a cross-sectional structure along the line BB ', illustrating the procedure of the sixth step of the OLED implant process of the present invention. In this process, first, the top of the indium tin oxide layer 906 and the top of the isolation layer 902
Implant a layer of OLED material 1002. Finally,
On top of the OLED material 1002, a cathode metal layer (cathode met
al layer) 1004 is implanted. FIG. 12 shows O of the present invention.
FIG. 2 is a schematic view of a pixel structure of an LED display element, showing a complete cross-sectional structure along a line BB ′. According to the present invention, the OLED in this layer is a blue OLED or a polymer LED as a light emitting material.

The present invention uses a blue LED or a polymer LED as a light source, arranges a CCM process, and converts blue light into red light or green light to form a full color LED.
In addition, by unifying the CCM and the LTPS thin film transistor in the same process, it is possible to manufacture a display element having high resolution, high efficiency, and a wide viewing angle.

FIG. 13 is a schematic view of the cross-sectional structure along the line AA 'in FIG. Thin film transistor of FIG. T ₁
The source and drain electrode areas 1102 and 1104 of
N ⁺ type impurity material.

[0033] The foregoing merely describes preferred embodiments of the present invention and does not limit the scope of the claims. Any equivalents and the like depending on the claims of the present invention shall fall within the claims of the present invention.

[Brief description of the drawings]

FIG. 1 shows the OE of a well-known thin film transistor.
FIG. 3 is a schematic plan view of an L element.

FIG. 2 is a schematic sectional view of FIG. 1;

FIG. 3 is a schematic circuit diagram of a full color OLED display element according to the present invention.

FIG. 4 is a schematic plan view of a full color OLED display element according to the present invention.

FIG. 5 is a schematic view of a cross-sectional structure along a line BB ′, illustrating a procedure of a black matrix forming process of a full-color OLED display element according to the present invention.

FIG. 6 is a schematic view of a cross-sectional structure along the line BB ′, illustrating a procedure of a process of forming a polysilicon island of a full-color OLED display element according to the present invention.

FIG. 7 is a schematic view of a cross-sectional structure along a line BB ′, illustrating a procedure of a gate forming process of a full-color OLED display element according to the present invention.

FIG. 8 is a schematic view of a cross-sectional structure along a line BB ′, illustrating a procedure of an intermediate layer forming process of a full-color OLED display element according to the present invention.

FIG. 9 is a schematic diagram of a cross-sectional structure along the line BB ′, illustrating a CCM process procedure (a) of a full-color OLED display element according to the present invention.

FIG. 10 is a schematic view of a cross-sectional structure along the line BB ′, illustrating the CCM process procedure (b) of the full-color OLED display element according to the present invention.

FIG. 11 is a schematic view of a cross-sectional structure along the line BB ′, illustrating a CCM process procedure (c) of the full-color OLED display element according to the present invention.

FIG. 12 is a schematic diagram of a cross-sectional structure along the line BB ′, illustrating the procedure of an OLED implant process of a full-color OLED display element according to the present invention.

FIG. 13 is a schematic view of a cross-sectional structure along the line AA ′ in FIG. 4;

[Explanation of symbols]

100 Well-known thin-film transistor organic electroluminescence (OEL)
Element 101, 102 Thin film transistor 103 Storage capacitor 104 Self-luminous OEL pad 105 Source bus 106 106 Gate bus 107 Ground bus 201 Insulating substrate 202 First gate insulating layer 204 Polysilicon gate layer 206 Gate bus 208 Polysilicon island 212 Second insulating layer 222 Top layer electrode 224 Isolation layer 226 Anode electrode layer 232 OEL layer 234 Cathode electrode layer 300 Full color organic light emitting diode (OLED) display element pixel structure of the present invention T ₁ , T ₂ thin film transistor _CS storage capacitor 301 Gate line 302 Data line 303 OLED 403 Black matrix 405 Data bus line 406 Gate bus line 407 Vdd bus line 501 Insulating substrate 502 Black matrix 504 Buffer layer 602 Polysilicon layer 604 N ⁺ type impurity 606 P ⁺ type impurity 608 Gate oxide layer 702, 704 Gate electrode 706 Gate metal 802 During layer 902 isolating layer 904 color conversion medium (CCM) area 906 material indium tin oxide 1002 OLED 1004 metal cathode layer 1102, 1104, N ⁺ -type impurity

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H05B 33/10 H05B 33/10 33/14 33/14 A 33/22 33/22 Z F term (Reference) 3K007 AB03 AB04 AB17 AB18 BA06 BB06 CA01 CB01 CB04 DA01 DB03 EB00 FA01 GA04 5C094 AA07 AA08 AA43 AA48 AA53 BA03 BA12 BA27 BA32 CA19 CA24 DA13 DB01 EA04 EA05 EB02 ED03 FA01 FA02 FB01 FB15 FB14 FB15

Claims (15)

[Claims] 1. The following 1. 1. a black matrix implanted and defined on the top surface of the insulating substrate; 2. a buffer layer implanted on top of the black matrix and defining therein the source and drain electrode areas of the first thin film transistor and the source and drain electrode areas of the second thin film transistor; 3. a polysilicon island implanted on top of the buffer layer and defined and formed using laser crystallization and etching; 4. a gate layer implanted on top of the polysilicon island, defining gate electrodes of the first and second thin film transistors therein; 5. a storage capacitor; 6. an intermediate layer that is implanted on the gate layer and the polysilicon island, on which the source and drain electrodes are implanted to define the metal area of the source and drain electrodes; 7. an isolating layer implanted on top of the intermediate layer and defining a color conversion media area therein; 8. a layer of transparent conductive material implanted on top of the isolation layer; 9. an OLED element implanted on top of the transparent conductive material layer and on the isolation layer; A pixel structure of a full-color OLED display element having a cathode metal layer implanted on the OLED material element and connected to and manufactured on a top layer surface of one insulating substrate having a top layer surface and a bottom layer surface. 2. The pixel structure of claim 1, wherein the OLED element is electrically connected to a drain electrode of the second thin film transistor. 3. The pixel structure of claim 1, wherein the drain electrode of the first TFT and the gate electrode of the second TFT are electrically connected. 4. The pixel structure of claim 1, wherein the second thin film transistor is an LTPS thin film transistor for supplying a current to the OLED element. 5. The full color OLED display element pixel structure according to claim 1, wherein the second thin film transistor is an active drive element. 6. The pixel structure of claim 1, wherein the gate electrode of the second thin film transistor is electrically connected to the storage capacitor. 7. The full color OLED display element pixel structure according to claim 1, wherein the second TFT and the OLED element are connected in series, and the straight capacitor and the first TFT are connected in series. 8. The following steps: (a) a step of preparing an insulating substrate having a top layer surface and a bottom layer surface; implanting a black matrix on the top layer surface of the insulating substrate; Implanting a buffer layer on top of the buffer layer; (b) implanting a polysilicon layer on top of the buffer layer to define the source and drain electrode areas of the first TFT and the source and drain electrode areas of the second TFT; (c) a procedure for forming a polysilicon island using a laser crystal method and an etching method; (d) a procedure for implanting a conductive material on the polysilicon island to form a gate layer; An intermediate layer is implanted on the polysilicon island, and the source electrode and the drain are (G) implanting and forming electrodes and forming metal areas for source and drain electrodes; (f) implanting an isolation layer on top of the intermediate layer and forming a color conversion medium CCM area; (g) ) Implanting a transparent conductive material layer on the isolation layer to form the transparent conductive material layer; (h) Implanting an OLED material on the transparent conductive material layer and the isolation layer; (i) The pixel structure process of the full color OLED display element, which consists of implanting a cathode metal layer on top of the OLED material. 9. In the step (b), the source electrode and the drain electrode area of the first thin film transistor are made electrically conductive by adding an N ⁺ -type impurity to the upper part of the buffer layer. 9. The pixel structure process for a full-color OLED display element according to claim 8, wherein the drain electrode area is electrically conducted by putting a P ⁺ type impurity on the buffer layer. 10. The pixel structure process for a full color OLED display element according to claim 8, wherein in step (d), the conductive material includes a gate oxide and a gate metal. 11. The method of claim 8, wherein step (d) further includes the step of defining the gate electrodes of the first and second thin film transistors in the gate layer.
Pixel structure process of LED display element. Step (f) The step of defining the CCM further includes the following steps: (f1) a step of etching the isolation layer to thereby form a part of a contact area between the CCM area and the electrode layer; (f2) ) The procedure of repeating spin coating and general photolithography on this CCM area to form individual CCM patterns of red, green and blue pixels; and (f3) Sputtering a transparent conductive material layer on top of this display element. 9. The pixel structure process for a full-color OLED display element according to claim 8, comprising a step of limiting the transparent conductive material layer. 13. The pixel structure process for a full color OLED display element according to claim 8, wherein in step (g), the transparent conductive material layer is indium tin oxide. 14. The pixel structure process of a full color OLED display element according to claim 8, wherein in step (h), the OLED is a blue OLED as a light emitting material. 15. In the step (h), the OLED is a polymer light emitting LE.
9. The pixel structure process of a full color OLED display element according to claim 8, wherein D is a light emitting material.