Pixel size of pyramidal pixel

In addition, the relationship between gain factor and pixel size of ALEL, as illustrated in Fig. 5.10, was investingated. From the results, the case of the pixel size of ALEL equal to the pixel size of OLED panel obtained the maximal gain factor, and the pixel spacing effect appeared in the smaller pixel size of ALEL.

0.8

Pixel size of ALEL : Pixel size of OLED panel = 1:1

Pixel

Fig. 5.10 Illustration of the relationship between gain factor and pixel size.

5.3 Comparison

For comparison, two OLED panels with ALELs were demonstrated in Fig. 5.11, and the CPT OLED panel with the optimized ALEL showed a gain factor of 2.03, which was based on the process limitation. Because the pixel size of ALEL was different from that of X company, pixel spacing effect would cause more serious moire patterns and larger gain factor loss on X company’s OLED panel.

Fig. 5.11 Photographs of OLED panels with ALELs (a) CPT 7” OLED panel and (b) ‘X’

company 1.5” OLED panel.

‘X' company 1.5” OLED Panel

OLED Panel ALEL

CPT 7” OLED Panel

CPT 7” OLED Panel

5.4 Summary

The experiments, including ALEL fabrication, measurements from Chromameter and Conoscope, were implemented and successfully demonstrated the improvements of luminance and angular distribution of the proposed ALEL, designed for the CPT OLED panel. Based on one pixel size of ALEL fitting one pixel size of OLED panel, ALEL shifts along x and y axes are allowed for the OLED panel to be free from moiré pattern. Meanwhile, the measured results of several alignment cases were investigated and explained as the pixel spacing effect.

According to the experimental curves of gain factor versus variables of ALEL, the higher luminance efficiency correlates to smaller opening area ratio, narrower pixel spacing, which agrees with the simulated results. Furthermore, the CPT OLED panel with the optimized pyramidal ALEL yields a gain factor of 2.0.

Chapter 6

Conclusions and future work

hancing layer designed for on CPT OLED panel was proposed and successfully demonstrated. In simulations, we analyzed the transmittance at the interface between the top-glass substrate and air to confirm that the Fresnel equations are necessary for modelling a pyramidal ALEL. Several important features of design rules for ideal ALEL alignment on OLED panel can be derived from the results:

(a) smaller opening area ratio (b) narrower pixel spacing (c) tilt angle of 50º~55º.

Optimized pyramidal ALEL yields a gain factor of 1.7 which produces higher light efficiency than other structures in our simulation results. For alignment issue, the area of pixel spacing cross light source was the main factor of the gain factor loss (pixel spacing effect).

The entire fabrication processes we utilized to fabricate the ALEL include the typical

material, p S), for replication is considered to have a similar refraction index as optical glass. As a result, based on one pixel size of ALEL fitting one pixel size of OLED panel, ALEL shifts along x and y axes are allowed for the OLED panel to be free from moiré pattern. Meanwhile, the measured results of several alignment cases were investigated and explained as the pixel spacing effect. According to the experimental results of gain factor versus variables of ALEL, the higher luminance efficiency correlates to smaller 6.1 Conclusions

The pyramidal array light-en

semiconductor fabrication processes and plastic modeling replication techniques. The plastic oly-dimethyl-siloxane (PDM

opening area ratio, narrower pixel spacing, which agrees with the simulated results.

OLED panel with the optimized pyramidal ALEL yields a gain factor of 2.0. From

red by UV light simultaneously. Thereafter the UV-gel-coated substrate is peeled off from the roller and then the prisms are formed. The materials are considered for high throughput and yield rate of mass production. The future work is to replicate the ALEL by various thicknesses of PET and various recipes of UV gel and to evaluate improvements of luminance efficiency of the PET-based ALEL on CPT OLED panel.

Fig. 6.1 The current manufacturing process and materials of BEF.

Furthermore, the CPT

the mentioned analyses, the structure of ALEL has the distinguished capability to eliminate the total internal reflection effect, thus, light efficiency and gain factor of OLED panel can be increased significantly.

6.2 Future work

6.2.1 New ALEL fabrication process

A fabrication process to manufacture brightness enhancing film(BEF) is as illustrated in Fig.6.1. The thin film of UV gel coated on a polyethylene terephthalate (PET) substrate is pressed by a roller with microstructures and cu

Polyethylene terephthalate (PET)

6.2.2 New pixel size design for ALEL

t to fit one pixel of an OLED panel, and m. However, in order to keep high yield ass production, the height of microstructure should be limited to match the demolding process. For example, the height of BEF is optimized to be less than 30 µm. T

In this study, the pixel size of ALEL had been se the height of ALEL had been optimized as 150~200 µ rate and high throughput of m

herefore, the new pixel size of ALEL will be designed to fit the “subpixel” of an OLED panel, as shown in Fig. 6.2. The future works are to simulate the new design by ASAP^TM and to fabricate new ALEL in order to obtain the maximum gain factor.

~200 µm

1 pixel

1

1 subpixel size of OLED panel

size of ALEL

pixel size of OLED panel

Fig. 6.2 The new pixel size design for ALEL.

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Vita

A. GENERAL INFORMATION Name: Ming-Lung Chen / 陳明倫

E-mail Address : amitaallen.iod93g@nctu.edu.tw B. EDUCATION

◆M.S. in Photonics and Display Technologies Chiao Tung University, Hsinchu, Taiwan Advisor: Prof. Han-Ping D. Shieh

Feb.05’~ July 06’

◆M.S. in Chemical Engineering & Materials Science Yuan Ze University, Taoyuan, Taiwan

Advisor: Prof. Sheng-Hsiung Lin

Sep. 94’~ June 96’

◆B.S. in Chemical Engineering & Materials Science Yuan Ze University, Taoyuan, Taiwan.

Sep. 90’~ June 94’

C. AWARD

◆ Student Paper Award, Optics & Photonics Taiwan 2005 D. PUBLICATION

◆ Ming-Lung Chen, An-Chi Wei, and Han-Ping D. Shieh, "Optimization of micro-structured light-enhanced layer for OLED panel," OPT 2005.

◆ Ming-Lung Chen, An-Chi Wei, and Han-Ping D. Shieh, "Improved output coupling efficiency of OLED panel using array light-enhanced layer," TDC 2006.