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Patent Issued for Organic Light-Emitting Display with Black Matrix

May 14, 2014



By a News Reporter-Staff News Editor at Electronics Newsweekly -- Au Optronics Corp. (Hsin-Chu, TW) has been issued patent number 8710733, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventors are Lee, Hsin-hung (Hsinchu, TW); Shih, Ming-chang (Yuanlin Township, Changhua County, TW).

This patent was filed on April 5, 2010 and was published online on April 29, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "The present invention relates to a method of forming an organic light-emitting display, and more particularly, to a method of forming an organic light-emitting display having a black matrix.

"With a rapid development of monitor types, novelty and colorful monitors with high resolution, e.g., liquid crystal displays (LCDs), are indispensable components used in various electronic products such as monitors for notebook computers, personal digital assistants (PDA), digital cameras, and projectors. The demand for the novelty and colorful monitors has increased tremendously.

"Liquid crystal display (LCD) monitors control pixel luminance by adjusting voltage drop applied on a liquid crystal layer of the liquid crystal display. Differing from liquid crystal displays (LCDs), Organic Light Emitting Displays (OLEDs) determine the pixel luminance by adjusting forward bias current flowing through an LED. With self-lighting technique without requiring additional light source, OLEDs provide faster response time period than LCDs. In addition, OLEDs have the advantages of better contrast and wider visual angle. More important, OLEDs are capable of being manufactured by existing TFT-LCD process. The commonly used OLEDs utilize a low-temperature polysilicon thin film transistor (LTPS TFT) substrate or amorphous silicon (a-Si) substrate.

"Please refer to FIG. 1, which shows a structure of a thin film transistor applied in an organic light emitting displays (OLEDs) according to the prior art. In prior art, for forming an Organic Light Emitting Display (OLED) 100, a black matrix 101 with a predetermined size is formed on a glass substrate 102. Next, depositing a buffer layer 104 and an amorphous thin film (not shown) over the black matrix 101 and the glass substrate 102; the amorphous thin film is recrystallized as a poly crystalline thin film by using excimer laser annealing (ELA) process. Furthermore, etching the poly crystalline thin film to form a pattern named as the semiconductor layer 106 is performed by using a first photo-etching-process (PEP). Afterward, a gate insulator 108 is deposited on the semiconductor layer 106 and the buffer layer 104.

"Following this procedure, a gate metal 110 is formed using a metal-depositing process and a second PEP. Then, a source 103 and a drain 105 are formed by performing a Boron ion-implanting process for the semiconductor layer 106 using the gate metal 110 as a self-alignment mask. An inter-layer dielectric (ILD) 112 is deposited on the gate metal 110 and the gate insulator 108, and a third PEP is performed to remove a portion of the ILD 112 and the gate insulator 108 on source 103 and drain 105 to generate via holes 115. Next, performing a metal-depositing process and a fourth PEP to generate metal layers 114 (i.e. signal line and drain metal) which covers the via holes 115 and connecting to the source 103 and the drain 105. Then, a planarization layer 116 is deposited on the metal layer 114 and the ILD 112. And a fifth PEP is performed to remove a portion of the planarization layer 116 on the metal layer 114 connecting to the drain 105. After that, an Indium Tin Oxide (ITO) layer, serving as transparent electric conductivity film, is formed on the planarization layer 116. Then, a display electrode 118 is generated by using the sixth PEP. Finally, a light-emitting layer 120 and a cathode metal layer 122 can be sequentially performed to complete fabrication of the OLED 100.

"In general, a pixel has a light-passing region 130 and a non-light-passing region 132 including the black matrix 101. The use of the black matrix 101 is to block light, thereby enhancing chromatic contrast and facilitating photo efficiency of a polarizer. Traditionally, the black matrix 101 fabricated at the bottom of the OLED 100, is a metal film having advantages of easy etching and well light-blocking. As shown in FIG. 2, the positions of the black matrix 101 relative to other layers of a thin film transistor before and after a heating process according to the prior art. In LTPS processes, especially the recrystallization process, high temperature may make the glass substrate shrink, resulting in a misalignment of the black matrix pattern with the other layer of TFT patterns which are formed after the black matrix. The use of a costly non-anneal glass is a resolution, however, cost of the whole OLED may rise as a result of using non-anneal glass."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventors' summary information for this patent: "An objective of the present invention is to provide an organic light-emitting display and a method for forming the organic light-emitting display, to solve the problem existing in prior art.

"Briefly summarized, the claimed invention is a method for forming an organic light-emitting display (OLED). The method comprises the steps of providing a substrate, forming a black matrix on the substrate, forming a buffer layer on the black matrix, simultaneously patterning the black matrix and the buffer layer, and forming a thin film transistor and a display electrode over the buffer layer.

"According to the claimed invention, a method for forming an organic light-emitting display comprises the steps of providing a substrate, forming a black matrix on the substrate, forming a buffer layer on the black matrix, forming a semiconductor layer on the buffer layer, simultaneously patterning the black matrix and the buffer layer, and forming a display electrode over the semiconductor layer.

"According to the claimed invention, a method for forming an organic light-emitting display comprises the steps of providing a substrate, forming a black matrix on the substrate, forming a buffer layer on the black matrix, forming a gate metal over the black matrix, depositing a gate oxide layer covering the gate metal and the buffer layer, forming a semiconductor layer on the gate oxide layer, and simultaneously patterning the gate oxide layer, the black matrix and the buffer layer.

"According to the claimed invention, an organic light-emitting display comprises a substrate, a black matrix disposed on the substrate, a buffer layer covering the black matrix, a thin film transistor disposed on the buffer layer, a display electrode electrically connected to the thin film transistor, and a light-emitting diode disposed on the display electrode. The black matrix has a first pattern, and the buffer layer has a second pattern substantially equal to the first pattern of the black matrix.

"These and other objectives of the present invention will become apparent to those of ordinary skilled in the art after reading the following detailed description of the preferred embodiment that is illustrated in the various figures and drawings."

For the URL and additional information on this patent, see: Lee, Hsin-hung; Shih, Ming-chang. Organic Light-Emitting Display with Black Matrix. U.S. Patent Number 8710733, filed April 5, 2010, and published online on April 29, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=70&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=3486&f=G&l=50&co1=AND&d=PTXT&s1=20140429.PD.&OS=ISD/20140429&RS=ISD/20140429

Keywords for this news article include: Electronics, Semiconductor, Au Optronics Corp..

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Source: Electronics Newsweekly


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