Dual-frame decentralized fusion scanning for digital drive on-silicon microdisplays

Yang Yuchen; Ji Yuan; Chen Wendong; Mu Tingzhou; Zhang Chunyan; Ran Feng

doi:10.12086/oee.2020.190366

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Yang Y C, Ji Y, Chen W D, et al. Dual-frame decentralized fusion scanning for digital drive on-silicon microdisplays[J]. Opto-Electron Eng, 2020, 47(11): 190366. doi: 10.12086/oee.2020.190366

Citation:

Yang Y C, Ji Y, Chen W D, et al. Dual-frame decentralized fusion scanning for digital drive on-silicon microdisplays[J]. Opto-Electron Eng, 2020, 47(11): 190366. doi: 10.12086/oee.2020.190366

Dual-frame decentralized fusion scanning for digital drive on-silicon microdisplays

Microelectronic Research & Development Center, Shanghai University, Shanghai 200444, China

Fund Project: Supported by National Natural Science Foundation of China (61674100, 61774101) and Civil-military Integration Project(2019-jmrh1-kj37)

More Information

Corresponding author: Ji Yuan. E-mail:jiyuan@shu.edu.cn

Received Date 28 June 2019

Revised Date 29 November 2019

Published Date 15 November 2020

Abstract

Abstract

When the microLED is in the forward working direction, it is difficult to precisely adjust its voltage to obtain different brightness. Moreover, when the microLED/OLED is turned on, they will be in a closed state for a long time, causing the image display brightness to be deteriorated by the human eye. In order to solve these problems, this paper proposes a dual-frame decentralized fusion scanning strategy to achieve different brightness by adjusting the microLED/OLED on-time. Firstly, the method de-weights the data bits and inserts their on-times into the closed time. Then the data bit weights are double-frame fused after decentralization. Finally, the scanning order of the data bits is redefined. According to the proposed scanning strategy, we designed a scanning controller to drive digital on-silicon microdisplay. The results show that the dual-frame decentralized fusion scan proposed in this paper can accurately adjust the luminance of microLED/OLED and improve the brightness of the image observed by human eyes. Compared with other scanning strategies, the scanning strategy improves the scanning efficiency to 93.75%, the field frequency is increased to 2040 Hz, the scanning clock frequency is 102.36 MHz, and the scanning data bandwidth is reduced. The feasibility of the scan controller is proved by testing at last.
- luminance /
- dual frame decentralized fusion /
- digital drive on-silicon microdisplay /
- scan controller /
- scanning efficiency

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References

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Overview

Overview

Overview: MicroLEDs and OLEDs are the two leading edge display technologies. Compared to conventional LED technology, microLED has higher luminance and luminous efficiency, and lower power consumption at the same brightness. Both microLED and OLED luminescent materials can be grown on a silicon substrate to form an on-silicon microdisplay. When the microLED is in the forward working direction, it is difficult to precisely adjust its voltage to obtain different brightness. Moreover, the microLED/OLED will be in a closed state for a long time during working, resulting in deterioration of the brightness of the image observed by the human eye. In order to solve these problems, this paper proposes a dual-frame decentralized fusion scanning strategy to achieve different brightness by adjusting the microLED/OLED on-time. Firstly, the method de-weights the data bits and inserts their on-times into the closed time. Then the data bit weights are double-frame fused after decentralization. Finally, the scanning order of the data bits is redefined. According to the proposed scanning strategy, we designed a scanning controller to drive digital on-silicon microdisplay. The results show that the dual-frame decentralized fusion scan proposed in this paper can accurately adjust the luminance of microLED/OLED and improve the brightness of the image observed by human eyes. Compared with other scanning strategies, the scanning strategy improves the scanning efficiency to 93.75%, the field frequency is increased to 2040 Hz, the scanning clock frequency is 102.36 MHz, and the scanning data bandwidth is reduced. The digital drive on-silicon microdisplay system used in this paper is mainly divided into two parts. The first part is the microdisplay driver chip, which mainly includes row, column and pixel driver circuits. The second part is the scan controller, which will process the data signal from the video source and generate the control signal to control the operation of the microdisplay. When the video source data is entered, we need to process it in a certain way, such as image scaling, gamma correction, etc., and then transfer the data to the RAM module. The RAM module functions as a buffered data before data storage. When the cached data input to the RAM satisfies the burst length of the SDRAM, the data is input to the SDRAM module. The SDRAM module acts as an external memory for the frame buffer and rearrange the data according to the scanning policy. The scan control module receives the data transmitted by the SDRAM module and generates the timing required to control the microdisplay. Both RAM module and SDRAM are operated by ping-pong operation. Finally, the output module is used to configure the LVDS interface on the FPGA and the chip, and then transmit the control signal generated by the controller and the processed data signal to the microdisplay through the interface to display the image. The scan controller proved to be feasible by testing at last.