Development of High Performance and High Definition Display Manufacturing Technology for Large Size Flat Panel Display by Selective Laser Annealing

For just started 4K8K broadcasting, the number of pixels in the display are 16 times as many as Full High Definition Display. FPD for large size TV by the usual display technology cannot be applied. In this project, new functions needed for FPD mass production have been developed based on the technology to improve the performance of thin film transistor (TFT) for switching each pixels of FPD by means of selective laser annealing method. The new annealing system is expected to become an essential technology of FPD manufacturing for large size TV, because it leads to improve definition, narrow frame width and reduce manufacturing cost.

JST (President, Michinari Hamaguchi) has recognized the results of NexTEP’s project, “Laser Annealing Technology for Large size Flat Panel Display” as success. This development task was based on the research of Professor Junji Kido, Graduate School of Organic Materials Science, Yamagata University from March 2015 through March 2018. The research proceeded with the aim of practical application through V technology Co., Ltd (President: Shigeto Sugimoto, Address: 9F East Tower, YBP, 134 Godo-cho, Hodogaya-ku, Yokohama, Capital fund: 28 hundred million yen).

[Recent Issue]

To display the image signal of 4K8K broadcasting ^{Key Word 1}, the number of pixels is increased in proportion to the resolution so that the on-time of TFT of each pixel is shorter than the conventional amorphous silicon ^{Key Word 2} TFT ^{Key Word 3} devices. In this situation, if a laser annealing process is applied to large size FPD ^{Key Word 4} production, the annealed silicon TFT is improved and can be applied for high definition display. However, the investment and running cost are very high and cannot apply the annealing process for large size TV manufacturing.

[Result of this project]

The following new functions have been developed based on the technology to improve the performance of TFT by a selective laser annealing method. One of the developed functions is to in-situ monitor the annealed TFT performance in the annealing system and feedback to control the laser irradiation conditions. All these functions are installed in the prototype selective laser annealing system and confirmed the advantage of this functions to real large size panel.

[Impact]

Only adding this system to product line of large size FPD that uses the conventional amorphous silicon TFT, it leads to improve high definition, narrow frame width and reduce manufacturing cost. Then, the new annealing system is expected to become an essential technology of FPD manufacturing for large size TV.

<Explanation of Key Word>

Key Word 1) 4K8K
It shows 3840×2160 pixels for 4K, 7680 x 4320 pixels for 8K of resolution on monitor or others.

Key Word 2) Amorphous Silicon Film
It is the non-crystalline form of silicon.

Key Word 3) TFT device
It shows semiconductor switching device of amorphous silicon film on glass plate or others.

Key Word 4) FPD
It shows flat display device, such as wall mounted TV.