BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 (Prior Art) is a schematic illustration showing a conventional organic light-emitting display device.
FIG. 2A˜2C (Prior Art) is a schematic illustration showing a defect in the process of the conventional display device.
FIG. 3 (Prior Art) is a schematic illustration showing another defect of the conventional display device.
FIG. 4 is a schematic illustration showing a display device according to the invention.
FIG. 5 is a flow chart showing a method of manufacturing the display device according to the invention.
FIGS. 6A to 6G are schematic illustrations showing steps of FIG. 5.
FIG. 7 is a schematic illustration showing a display device whose switch element if formed by amorphous silicon process according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
The invention provides a display device and a manufacturing process by removing the film stacked in the light-emitting region of a sub-pixel. The particles and the unsmooth surface encapsulated or deposited in the film are simultaneously removed by etching the stacked film. In order to remove the particles and the unsmooth surface completely, the substrate is over etched such that a part of the first electrode is disposed in a recess region of the substrate and the bottom surface of the first electrode is lower than the substrate upper surface. Thus, it is possible to ensure that the particles and the unsmooth surface can be removed completely. The display device and the method of manufacturing the same according to the invention will be described with reference to two preferred embodiments, which illustrate how the particles and the unsmooth surface are removed completely.
First Embodiment
FIG. 4 is a schematic illustration showing a display device 300 according to the invention. Referring to FIG. 4, a display device 300 includes a substrate 340 and a plurality of sub-pixel 310. The substrate 340 has a substrate upper surface 340a. The sub-pixel 310 includes a light-emitting element 330 and a switch element 320. Herein, the structure of the sub-pixel 310 is illustrated by taking only one of the switch elements 320 and the light-emitting elements 330 as an example. The light-emitting element 330 includes a first electrode 331, a light-emitting layer 333 and a second electrode 332. The first electrode 331 has a first electrode bottom surface 331a. The light-emitting layer 333 is disposed on the first electrode 331. The second electrode 332 is disposed on the light-emitting layer 333. The switch element 320 is disposed on the substrate upper surface 340a, and the switch element 320 is electrically connected to the light-emitting element 330.
In the display device 300 of the invention, the substrate 340 further has a recess region 341, which is lower than the substrate upper surface 340a of the substrate 340. In addition, the first electrode 331 is disposed on the recess region 341. That is to say, the films on the substrate 340 in a light-emitting region A330 of the sub-pixel 310 is completely removed, such that a part of the first electrode bottom surface 331a is lower than the substrate upper surface 340a.
In this embodiment, the switch element 320 is a thin film transistor (TFT) and the light-emitting element 330 is an organic light emitting diode (OLED).
As shown in FIG. 4, the recess region 341 has the following features. The recess region 341 has a recess region bottom surface 341a and an inclined surface 341b, which inclines from the substrate upper surface 340a to the recess region bottom surface 341a. In addition, the inclined surface 341b has a top end T and a bottom end B, and a horizontal distance HD between the top end T and the bottom end B is greater than a vertical distance VD between the top end T and the bottom end B.
In addition, a cross-sectional profile of the above-mentioned inclined surface 341b is non-linear. As shown in FIG. 4, the cross-sectional profile is a curve.
In the method of manufacturing the display device according to the invention, how the structure of the display device 300 of FIG. 4 is formed and how the particles and the unsmooth surface encapsulated in the film are effectively removed will be described with reference to the following drawings.
Please refer to FIGS. 5 and 6A to 6G. FIG. 5 is a flow chart showing a method of manufacturing the display device according to the invention. FIGS. 6A to 6G are schematic illustrations showing steps of FIG. 5. In step S1˜S3 of FIG. 5, please refer to FIG. 6A. Firstly a substrate 340 having a substrate upper surface 340a is provided. The substrate 340 may be a hard glass substrate or a flexible soft substrate. In this embodiment, the substrate 340 is a hard glass substrate, for example. Next, in step S2 of FIG. 5, a switch element 320 is formed on the substrate 340.
Next, in step S3 of FIG. 5, a recess region 341, which is lower than the substrate upper surface 340a, is formed on the substrate 340, as shown in FIG. 6A. The recess region 341 may be formed by way of wet etching, dry etching, dry plus wet etching, which combines the dry etching process with the wet etching process. Preferably, a better effect may be obtained using the wet etching process.
Preferably, the recess region 341 is formed by removing a 0.01-to-10 μm thickness of the substrate 340 downward from the substrate upper surface 340a. The downwardly removed thickness may be properly adjusted according to different processing parameters and the materials of the film and the particles.
In this step, removing the insulating layer 312, the insulating layer 311 and a part of the substrate 340 downward can remove the particles 191 interposed between the film layers. In addition, a clean recess region bottom surface 341a without any particle is left.
Then, in step S4 of FIG. 5, a light-emitting element 330 is formed in the recess region 341, as shown in FIGS. 6B to 6G. The light-emitting element 330 is electrically connected to the switch element 320. In FIG. 6B, an insulating layer 313 covering a source/drain connecting wiring 322 of switch element 320 as well as the recess region 341 is formed. Then, as shown in FIG. 6C, a contact hole 313a for exposing a part of the source/drain connecting wiring 322 is formed. Meanwhile, the insulating layer 313 of the recess region 341 is also exposed the recess region bottom surface 341a substantially corresponding the light-emitting region A330. Next, as shown in FIG. 6D, a first electrode 331 is formed on the recess region 341 and the contact hole 313a such that the first electrode bottom surface 331a contacts the substrate 340. In addition, the first electrode bottom surface 331a is lower than the substrate upper surface 340a by 0.01 to 10 μm. Heretofore, the first electrode 331 of the light-emitting element 330 is formed.
Next, as shown in FIG. 6E, an insulating layer 314 covering the switch element 320 and a part of the first electrode 331 is formed. The insulating layer 314 exposes the first electrode 331 of the light-emitting region A330. Then, as shown in FIG. 6F, a light-emitting layer 333 is formed on the first electrode 331. The contact portion between the light-emitting layer 333 and the first electrode 331 is located in the light-emitting region A330. Heretofore, the light-emitting layer 333 of the light-emitting element 330 is formed.
Then, as shown in FIG. 6G, a second electrode 332 is formed on the light-emitting layer 333. The second electrode 332 contacts the light-emitting layer 333 for forming the light-emitting element 330. Thus a display device 300 is constituted.
According to the method of manufacturing the display device 300, it is possible to effectively remove the particles deposited on the film in the light-emitting region A330.
Second Embodiment
In addition, a display device whose switch is formed by a amorphous silicon process may also be applied in the invention. In the process of manufacturing the display device, which applies the amorphous silicon process, how to form the structure of the display device 300 of FIG. 4 and how to remove the unsmooth surface encapsulated in the film effectively. The structure of the display device whose switch element is formed by the amorphous silicon process will be described with reference to the following drawings.
The difference between the structure of the display device 400 in the second and the display device 300 in the first embodiments is the structure of the switch element 420, so detailed descriptions of the same processes will be omitted
Please refer to FIG. 7. FIG. 7 is a schematic illustration showing a display device whose switch element if formed by amorphous silicon process according to the invention. The switch element 420 comprises a gate electrode 421 and two source/drain 422 is disposed on the substrate 340 and the switch element 320 is electrically connected to the light-emitting element 330. Wherein the switch element 420 which formed by the amorphous silicon process is a bottom-gate type structure, for example. In the display device 400 of the invention, the substrate 340 further has a recess region 341, which is lower than the substrate upper surface 340a of the substrate 340. In addition, the first electrode 331 is disposed on the recess region 341. That is to say, the films on the substrate 340 in a light-emitting region A330 of the sub-pixel 410 is completely removed, such that a part of the first electrode bottom surface 331a is lower than the substrate upper surface 340a.
In the display device and the method of manufacturing the same according to the embodiments, the film stacked in the light-emitting region of the sub-pixel is removed and a recess region lower than the substrate upper surface is formed, or a part of the first electrode is configured to directly contact the substrate and be lower than the substrate upper surface. Thus, the in-film particles or the unsmooth surface encapsulated in the film can be completely removed according to the above-mentioned method. Accordingly, the display device and the method of manufacturing the same according to the invention have the following advantages.
First, the particles encapsulated in the film layer and the unsmooth surface of the buffer layer on the substrate can be completely removed. No matter what the material of the particle is and the quantity of the unsmooth surface, removing the stacked film in the light-emitting region can completely remove the particles and the unsmooth surface encapsulated in the film layer.
Second, the yield can be greatly improved. The particles and the unsmooth surface encapsulated in the light-emitting region are always the main reason of producing the bad display device. This is because the short-circuited phenomenon between the first electrode and the second electrode caused by the protruding projection and the phenomenon of light scattering or light absorption owing to the above-mentioned defects have become a serious proof against the product quality. According to the display device and the method of manufacturing the same in this invention, the product yield can be greatly improved, and the stable quality of the product can be obtained.
Third, the manufacturing cost can be greatly reduced. The bad display device usually cannot be reworked, or wastes a lot of human works, materials and apparatus cost when it is reworked. According to the display device and the method of manufacturing the same in this invention, the product yield can be improved and the manufacturing cost can be reduced.
While the invention has been described by way of examples and in terms of referred embodiments, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Patent Application
20080023694
