P-74: WITHDRAWN: P-75: Characteristics of Two-level Sustain Waveform in AC-PDP

Characteristics of Two-level Sustain Waveform in AC-PDP

Jongsun Park, Sangheum Eom, and Jungwon Kang The Department of Electronics and Electrical Engineering Dankook University,

226, Jukjeon-dong, Suji-gu, Yongin-si, Gyeonggi-do, 448-701, Korea

Abstract In this paper two-level sustain-waveforms for ac-PDP were proposed and studied. The luminance, IR emission and current of sustain discharge were measured for four different waveforms and these were compared to the results of a conventional waveform. The proposed waveform showed 20% higher luminance and 55.6% higher efficiency than the conventional.

Author Keywords Plasma Display; Driving Waveform; Sustain Waveform; IR emission; iCCD;

1. Introduction 3D and high quality contents are leading a new market of the flat panel displays. As a resolution of panel is increase, the required time of the address period is increased and the time for the sustain period is decreased. In 3D application, one TV-field needs to be separate for left-eye field and right-eye field. Therefore, due to decrement of sustain period, the luminance of panel is decreased and it can be one of issues to be solved [1-2]. In this study several two-level sustain-waveforms were designed to improve the luminance and efficiency of 3D panel. With 7-inch test panel having 50-inch full-HD resolution, the luminance and IR emissions (823 nm and 828 nm) were measured for each case. Each result was compared to the result of the conventional sustain-waveform.

Fig. 1. Experimental set-up

2. Experimental

The experimental set-up is shown in Fig. 1. The waveform generators were located at the right-side of the table and the 7 inch test panel was located on the right side of the waveform generators. The designed waveforms were transferred from a computer to the waveform generators. IR emissions during sustain period were measured with IR scope and intensified CCD which were located in front and back of the test panel.

Four different two-level sustain-waveforms are shown in Fig. 2. In (a) and (b) waveforms, the sustain-pulses were applied to scan and sustain electrode sequentially. In (c) and (d) waveforms, the sustain-pulses were applied to scan and sustain electrode simultaneously. 300 V breakdown voltage was applied to the test panel at first. In all cases 10 pairs of sustain pulses were applied to the test panel for every 1.67 ms. The period of one-pair was 12 us and its duty was 83% [3-4].

(a) Case 1

(b) Case 2

(c) Case 3

(d) Case 4

Fig. 2. Tested sustain waveform; black line is a pulse applied to scan electrode and grey line is a pulse applied

to sustain electrode

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3. Results and Discussion With the waveform in Fig. 2(a), the optimal ratio between T1 and T2 (described in Fig. 2) was investigated. The dependence of luminance on the amplitude of Vs2 (also described in Fig. 2) was investigated together. The sum of T1 and T2 was fixed at 5 us for entire experiments.

Fig. 3 shows luminance according to five different ratios of T1 to T2. Vs2 was also varied, but the total bias (Vs1 + Vs2) was fixed at 220 V. When the ratio of T1 to T2 was 1:2 and Vs2 was 55 V, the luminance was 80.2 cd/m2 and it was the highest value. The luminance of the conventional sustain-pulse was 74.9 cd/m2 and it was 7.1% less than the highest value. In general the condition of T1: T2 = 1:2 showed the good performance under various Vs2.

Fig. 3. Dependence of luminance on T1:T2 ratio and Vs2

with the case 1 waveform

Fig. 4 shows IR emissions from sustain discharge of the conventional, case 1 and case 3 waveforms. The case 3 showed faster ignition and longer-duration of discharge than other cases and also showed the strong second emission [5].

Fig. 4. IR emissions during sustain period

Fig. 5. shows iCCD images during sustain discharge period of all cases. The images were measured with 0.02 us intervals [6]. In case of 3 and 4, after the first emission occurring from sustain to scan electrode, the second emission to the opposite direction was observed. iCCD images tended to be the same as the IR emissions. Based on iCCD measurement, the second emission is due to the movement of electrons to opposite direction

Fig. 5. iCCD image during sustain period

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Fig. 6. (1) Schematic Diagram of Conventional & Case 3 Waveforms; (2) Temporal Behavior of Wall Charges within

a Cell Fig. 6. shows the schematic diagram of conventional and Case 3 waveforms and estimated temporal behavior of wall-charges varying due to applied waveforms. There is a difference of initial wall-charge distribution between conventional and Case 3 waveforms. In Case 3 positive and negative polarity pulses were applied to scan and sustain electrodes at the same time, but in conventional waveform only positive polarity pulse was applied to scan or sustain electrodes sequentially. Therefore the difference could be caused [6-7].

Fig. 7. Current measurement during sustain period with

the conventional waveform

Fig. 7. shows the measured current during the sustain period at Vs = 220 V. The discharge current (= Id) was obtained by subtracting off-state current (= IOff) from on-state current (= IOn) .

Id = IOn - IOff

Fig. 8. Measured discharge current and luminance

Fig. 8. shows the dependence of current and luminance on the sustain voltage (= Vs) for 4 different waveforms. The proposed waveforms showed lower discharge current and higher luminance than those of the conventional.

Fig. 9 . Efficiency

Fig. 9. shows the dependence of efficiency on Vs for 4 different waveforms. The proposed waveforms showed higher efficiency than the conventional. Especially the case 3 showed 55.6% higher efficiency than the conventional at Vs = 220 V.

4. Conclusions At the same voltage level (220 V), the proposed sustain-waveform (case 3) showed 20% higher luminance and 55.6% higher efficiency than those of the conventional. The proposed waveform can be a good candidate of sustain waveform for the application of 3D and high resolution PDPs.

Acknowledgement This research was supported by a grant (F0004071-2011-34) from Information Display R&D Center, one of the Knowledge Economy Frontier R&D Program funded by the Ministry of Knowledge Economy of Korean government.

(a) Conventional

(b) Case

(2)

(1)

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J.PHYS.Ⅳ FRANCE 7, 1997. [2] J. P. Boeuf, JOURNAL OF PHYSICS D:APPLIED

PHYSICS, 2003. [3] Y. Seo, T. Kosaka, H. Inoue, N. Itokawa, and Y.

Hashimoto, SID’03, pp. 137-139, 2003. [4] Jongsun Park, Jungwon Kang, IDW’11, pp. 699-702, 2011.

[5] Nak-Won Choi, Jeong Hyun Seo, IEEE Trans. ELECTRON DEVICES. VOL. 56, NO. 12, DECEMBER, 2009.

[6] Tsai-Fu Wu, Chien-Chih Chen, Wen-Fa Hsu and Chien-Chou Chen, IEEE Inductry, 334-341, vol.1, 2002.

[7] G. Veronis, U. S. Inan, IEEE Trans. ON PLASMA SCIENCE, VOL. 33, NO. 1, 2005.

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