Ki-Hyung Park

High-speed driving method using bipolar scan waveform in AC plasma display panel

This paper proposes a new high-speed driving method using the bipolar scan waveform with a scan width of 1 /spl mu/s in an ac-plasma display panel. The bipolar scan waveform in an address period consists of a two-step pulse with two different polarities, i.e., a forward scan pulse with a negative polarity and reverse scan pulse with a positive polarity, which can produce two address discharges, including a primary address discharge for generating wall charges and secondary address discharge for accumulating wall charges. To produce the fast address discharge stably using the bipolar scan pulse during an address period, a new reset waveform is designed based on a V/sub t/ close curve analysis, and the address discharge characteristics examined under various reset and address waveforms. As a result of adopting the proposed driving method, a high-speed address with a scan width of 1 /spl mu/s is successfully obtained when using a checkered pattern on a 4-in test panel.

Improvement of luminous efficiency using high helium content in full-HD plasma-display panels

— The influence of the Xe (15%) and He (70%) fractions on the discharge and driving characteristics was compared in 50-in. full-HD plasma-display panels. The same improvement in the luminous efficacy was obtained when increasing either the Xe or He fraction. However, the discharge current with a high He fraction was smaller than that with a high Xe fraction. While the breakdown voltage was hardly influenced by an increase in the He fraction, it was significantly changed when increasing the Xe fraction. The formative and statistical time lags were only slightly changed with a high He fraction, yet significantly increased with a high Xe fraction. In addition, the relatively low luminance and driving-margin characteristics with a high He fraction were compensated for by controlling the capacitance of the upper dielectric layer.

Comparison of temporal dark image sticking produced by face‐to‐face and coplanar sustain electrode structures

Abstract The temporal dark image sticking phenomena are examined and compared for the two different electrode structures such as the face‐to‐face and coplanar sustain electrode structure. To compare the temporal dark image sticking phenomena for both structures, the differences in the infrared emission profile, luminance, and perceived luminance of the image sticking cells and the non image sticking cells were measured. It is observed that the temporal dark image sticking is mitigated for the face‐to‐face structure. The mitigation of the temporal dark image sticking for the face‐to‐face structure is due to the slight increase in the panel temperature induced by the ITO‐less electrode structure.

Analysis of Reset Discharge Characteristics in AC-Plasma Display Panel With Various Sustain Gaps Using

The effects of various sustain gaps on the reset discharge characteristics, particularly the discharge stability, are examined based on a Vt close-curve analysis. The Vt close-curve analysis shows that the reset discharge region producing a stable discharge under an MgO cathode condition is reduced in proportion to the increase in the sustain gap, resulting in discharge instability when a conventional reset waveform is applied with a wide-sustain-gap (over 200 mum) structure. Based on the Vt close-curve analysis, a modified reset waveform suitable for a wide-sustain-gap (= 200 mum) structure is proposed to prevent an unstable discharge. The effects of two parameters Vadd-bias and Vcom-bias in the modified reset waveform on the reset discharge as well as the address and first sustain discharges, are examined in detail.

V_{t}

To investigate the discharge characteristics such as a firing voltage and wall voltage condition by the conventional driving waveform in the ultra fine AC-PDP cells, the Vt close-curves are measured. Using the shape and shift of the Vt close curves measured from the various PDP cell sizes such as 50-in. full HD, 50-in. HD, and 42-in. HD grades, the discharge characteristics are analyzed in detail.

Close-Curve

A new first subfield waveform is proposed to enhance the low gray level linearity in AC-PDP. The proposed first subfield uses a ramp pulse instead of a square sustain pulse, thereby generating the lower minimum-luminance level stably and reducing the low gray level contour.

P‐96: Analysis of Discharge Characteristics on 50‐in. Full HD, 50‐in. HD, and 42‐in. HD PDP Cells using Vt Close‐Curve

The influence of plasma display panel (PDP) cell size on discharge characteristics is investigated in 50-in high-definition (HD) and full-HD (FHD) ac-PDPs using experiments and a 2-D simulation. When increasing the resolution of the 50-in PDP from HD to FHD, the discharge volume in a cell was reduced, yet the phosphor area per unit area was not reduced. The comparative experimental results showed a decreased luminous efficacy and IR efficiency for the FHD test panel of about 25%-29% and 26%-29%, respectively, indicating that the decreased luminous efficacy was mainly due to a decreased discharge efficiency, rather than the phosphor area. Meanwhile, the simulation results revealed that the degradation of the vacuum ultraviolet efficiency in the FHD cells was due to a decrease in the electron heating efficiency and Xe-excitation efficiency of the electrons. Specifically, the decrease in the electron heating efficiency was more critical, which was related to a smaller discharge space and shorter discharge path.

New first subfield waveform for improving low gray level linearity in AC-plasma display panel

This paper proposes a modified selective reset driving waveform that can lower the potential difference between the scan and address electrodes by applying the address-bias voltage (Va-bias) to the address electrode during the application of the rising pulse of Y-electrode in the selective reset-period. This address-bias voltage (Va-bias) plays a role in suppressing the wall-charge accumulation on the address electrode during the selective reset-period, thereby contributing to minimizing the wall-voltage variation during the address-period and as such allowing the higher voltage difference (=ΔVy) between the scan low voltage (Vsl) and the negative falling ramp voltage (Vnf) during an address-period without any misfiring discharge. When adopting the proposed selective reset waveform, the address discharge delay time is observed to be reduced by about 120 ns.

Influence of Cell Size on Discharge Characteristics in ac-PDPs With HD and full-HD Resolution

Abstract Auxiliary address pulse driving scheme is proposed for controlling and improving the color temperature of the 42‐inch WVGA ac‐plasma display panel (ac‐PDP) without sacrificing total luminance. Under a white‐background, the color temperature of 42‐inch ac‐PDP is improved by about 1,700 K, whereas under a black‐background, the color temperature of 42‐inch ac‐PDP is improved by about 3,200 K. In addition, by properly controlling the luminance in the R, G, and B cells, the color temperature of 42‐inch ac‐PDP can be raised from 5,827K to 10,705K.

P‐140: A Modified Selective Reset‐Waveform to Minimize Wall‐Voltage Variation During Address‐Period in Full‐HD PDP

A new bipolar ramp waveform that can reduce the minimum luminance level considerably is proposed to improve the low gray level expression in AC-PDP. In the new bipolar ramp waveform, the conventional first subfield with a sustain-period is replaced by the new first subfield that consists of the first negative square pulse and second positive ramp pulse during a scan-period. The weak discharge produced by the second positive ramp pulse is used to generate and control the low luminance level stably.