Changchun Cedar Electronics Technology Co.

Changchun, China

Changchun Cedar Electronics Technology Co.

Changchun, China

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Tian Z.-H.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Tian Z.-H.,Changchun Cedar Electronics Technology Co. | Miao J.,Changchun Cedar Electronics Technology Co. | Mao X.-Y.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | And 3 more authors.
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2016

In order to overcome the non-uniformity defects of image vignetting captured by camera in dot-to-dot correction on LED display screen, a vignetting correction method based on LED display screen and discrete position luminance measurement was put forward. First, the process of camera image acquisition and imaging features of LED display were analyzed. From this, a correction method of camera vignetting was proposed, a fitting surface of camera vignetting was obtained. Then, a vignetting correction factor matrix corresponding pixels on camera sensor was calculated. Using the above method, an experiment of single-box luminance correction of LED display screen was conducted. Experimental results indicate that the uniformity deviation of LED display screen can be narrowed from 6.69% to 1.49% after image vignetting factor calibration. After correction of camera image vignetting, non-uniformity surface distribution can be completely eliminated. Therefore, the “center-dark, surround-bright” defect on LED display screen is overcome, and the desired correction effect for multi-screens stitching display is achieved. © 2016, Science Press. All right reserved.


Tian Z.-H.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Tian Z.-H.,Changchun Cedar Electronics Technology Co. | Chen Y.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Chen Y.,Changchun Cedar Electronics Technology Co. | Miao J.,Changchun Cedar Electronics Technology Co.
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2014

In order to eliminate the Moiré phenomenon in LED display screen of digital camera, the mechanism and the characteristics of Moiré phenomenon were analyzed. A method of eliminating the Moiré phenomenon of high-density LED display screen which uses multiple optical scattering films was proposed. The Moiré phenomenon elimination device was simulated by using optical simulation program. Moreover, the key parameters of the Moiré phenomenon elimination device were optimized. A verification experimentation was demonstrated on a P2.5 mm high-density LED display screen sample box using the optimized Moiré phenomenon elimination device. The experimental results coincided with the theoretical analysis. The optimized device can greatly reduce the contrast of the Moiré phenomenon of LED display screen. Therefore, it can be proved that the method we proposed to eliminate the Moiré phenomenon of high-density LED display screen is effective.


Tian Z.-H.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Tian Z.-H.,Changchun Cedar Electronics Technology Co. | Wang R.-G.,CAS Changchun Institute of Optics and Fine Mechanics and Physics | Wang R.-G.,Changchun Cedar Electronics Technology Co. | And 3 more authors.
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2014

In traditional LED display screen, optical energy utilization rate and imaging filling ratio are very low. Based on the theory of non-imaging optics, a structure system and a design method are developed to improve optical energy utilization rate and imaging filling ratio of full-color LED display. Using compound parabolic concentrator (CPC), light diverging angle emitted from LED chips is transformed and compressed. Therefore, total reflection loss on external surface of display module can be avoided. Accordingly, optical energy utilization rate of display system is greatly improved. Based on uniform lighting principle of integrator-rod and light distribution principle of scattering, imaging filling ratio, pixel uniformity and primary color multiplexing area of LED display screen are improved. According to the above method, a P10 mm full-color LED display module is designed. Using LIGHTTOOLS software, the display module system is simulated and analyzed. The simulation results show that, optical energy utilization rate of system is higher than 70%, imaging filling ratio closes to 100%, uniformity of unit pixel area is better than 85%. The display module has the advantages of high energy utilization rate, high imaging filling ratio, uniform and soft showing, easy manufacturability.

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