• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.1
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• pp.48-52
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• 2012

The charged particle type display device is a kind of the reflectivity type display and shows an image by absorption and reflection of external light source. The charged particle is important factor for driving of the display and quantity of charge per mass of the charged particle determines the driving voltage, contrast ratio, response time, etc. But it is easy for the charged particles to be damaged in the putting process of the display and the damages cause lumping phenomenon of the charged particles. Because the lumping phenomenon makes high driving voltage, low quality of optical properties, short life time, etc, so the charged particles must be filled by stable putting methods. In this paper, we filled the charged particles into the panels by electric fields to improve the electrical and optical characteristics of the display. Also, we analyzed the driving characteristics of the charged particles according to the applied putting voltages.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.85-86
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• 2008

We have developed charged particle type display using opposite-charged two particles. We fabricated the charged particle type display to be controlled the addressing layers by putting voltage. To get the effect of number of layers, we measured driving voltage, reflectivity, viewing angle, and color characteristics, for 1~2 layer. Reflectivity was different according to the number of layers and wavelength of yellow particles is alike to that.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.53-54
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• 2007

Charged particle type display using particles which have opposite charge and color is based on effect of reversible optical property due to electric field. we designed mask pattern for fabrication of the charged particle type display based on glass substrate and investigated cell gap dependent of driving voltage and selectively driving method. the panel driven by our selectively driving method, we could obtain image which had vary little crosstalk caused by electrical interference and conform the last image maintained by memory effect without additional voltage.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.2
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• pp.169-173
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• 2009

We studied driving characteristics according to the ratio of mass and charging (m/q) value for charged toner particles with black and yellow color in charged particle type display panel. After biasing rectangle pulse to the transparency electrodes of putted panel with toner particles, its response time and contrast ratio are simultaneously measured using a laser as a optical source, photodiode as a detector and reflective system. As a results, contrast ratio is largest at the shortest response time region which is different to the particle because of m/q. We proposed relational equation for response time, m/q, cell gap and biasing voltage. It has not been studied and reported to analyze the relationship of response time, biasing voltage, lumping phenomena, cell gap, and contrast ratio for toner particle type display.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.66-67
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• 2007

We have developed reflective information display using opposite-charged two particles. An appropriate amount of both the yellow and the black powers are putted between the ITO patterned glass substrate separated with cell gap. The rib maintains the cell gap and prevents the interference between the pixels. When a negative voltage is applied to the upper ITO electrode, the positively charged black powder moves to the upper electrode viewing a black appearance. In case of positive voltage is applied to this electrode white particle is observed. So we analyzed the electrical and optical properties of our charged particle type display panel.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.35-40
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• 2008

In this paper, fundamental driving method and selective driving each cells of charged particle type display are described. To fabricate panel, mask patterns with cell area of $500{\mu}m{\times}500{\mu}m$ are designed. Gain of driving voltage due to increase of cell gap is observed on the basis of fundamental driving method. To selectively drive each cells of charged particle type display that is driven by passive matrix method, selective driving of charged particle type display is achieved after establishing interrelation of voltage of select cell and unselect. And than crosstalk of the driven panel is observed. It can be found that the last image is maintained without additional voltage by memory effect.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.25 no.2
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• pp.129-134
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• 2012

We analyzed the movement and response time of charged particles according to particle-inserting methods to understand the variation of quantity of q/m of charged particles, which is a very important factor in electrical and optical characteristics of the charged particle type display, such as lifetime, response time, contrast ratio, reflectivity, etc. For our study we used white and black charged particles of which diameter is $20{\mu}m$, prepared pieces of ITO(indium tin oxide) coated glass substrate, and formed ribs on the glass substrates. The width of a rib is $30{\mu}m$ and the cell size is $220{\mu}m{\times}220{\mu}m$. As the particle-inserting methods, the white and black charged particles were respectively inserted into a front and a rear panel with a very small electric field and also the mixture of the white and black charged particles were inserted into a rear panel. As a result of the driving characteristics of charged particles, the factors about variation of quantity of q/m according to the particle inserting method was experimentally demonstrate, showing very different driving voltage, response time, the particle movement, etc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.72-73
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• 2007

The charged particle have characteristics of high-contrast ratio and wide-view angle, quick-response time. When positive voltage is applied to the upper electrode, the yellow particles with negative charge move toward the upper substrate and the black particles with positive charge move toward opposite direction. We have developed the putting method that can fill particles in cell of panel and control the amount of charged particles. We investigated putting method, fabrication process, aging and driving for charged particle type display.

• Transactions on Electrical and Electronic Materials
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• v.15 no.6
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• pp.333-337
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• 2014

In this study, the use of a discharging process for charged particles is proposed to achieve an ideal electrical balance or neutralization and to improve the electrical and optical properties of a reflective electronic display. Here, negatively charged particles (white) and positively charged particles (black) are used. The q/m (charge per mass for a particle) values of the black and white particles are $+4.5{\mu}C/g$ and $-4.5{\mu}C/g$, respectively. We compared the movement of the charged particles by varying their discharging time. Stable movement of the charged particles is obtained with an appropriate discharging time, which resulted in improvements of the optical properties of the panel.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.1
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• pp.63-67
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• 2008

The charged particle type display is a kind of electronic paper showing information images using positive and negative charged particles ($<10{\mu}m$). In this work we used yellow(-) and black(+) particles which are respectively addressed to the cells of a upper and a rear substrate by using electric field. Our independent addressing method has strong points compared to the mixed particle putting method. The packaging with two orthogonal substrates and the aging process is followed by addressing process. The panel is sequentially driven by matrix method for each 4-unit cells. Layers of particles are controlled by barrier ribs and must be addressed to minimum 2 layers.