Display device and manufacturing method thereof

Abstract

A lower substrate including a first electrode and an upper substrate including a second electrode are opposed to each other, and a space between the two substrates is partitioned by a partition wall into pixels. In the lower substrate, a piezoelectric material is sandwiched between a third electrode and the first electrode, thereby forming a vibration-generating portion. In the space, negatively charged black particles and positively charged white particles are contained. In a display operation, a signal voltage corresponding to an image signal is applied between the first and second electrodes, generating an electric field, whereby the black particles and the white particles travel between the electrodes and adhere to the respective electrode surfaces to perform the display operation. In rewriting the display, a high-frequency sine wave voltage is applied between the first electrode and the third electrode. Thereby, the piezoelectric material causes a piezoelectric effect, and consequently the vibration-generating portion generates vibration. By transmitting this vibration to the black particles and the white particles, aggregated particles are dissociated and particles adhering to the electrode surfaces are detached therefrom, and these particles are dispersed in the space to erase the display. After erasing the display, a signal voltage corresponding to an image signal is newly applied between the first electrode and the second electrode to perform a display operation.

Description

technical field [0001] The present invention relates to a reversible display device having a display element that performs display by moving a plurality of colored particles by an electric field between a pair of opposing substrates, and a manufacturing method thereof. Background technique [0002] Conventionally, twisted nematic liquid crystal (hereinafter referred to as TN liquid crystal) display devices and organic electroluminescence (hereinafter referred to as organic EL) devices are known as thin, low-power display devices used in portable information terminals. The TN liquid crystal display element changes the alignment state of the liquid crystal molecules in the liquid crystal layer only when a voltage is applied, and thereby controls the transmittance of light passing through the liquid crystal layer to perform display. Therefore, operating power for display is always required, and images cannot be displayed in a power-off state. In addition, since an organic EL e...

AI Technical Summary

Problems solved by technology

Here, when moving particles between electrodes of opposite polarity according to polarity, the Coulomb force of the electric field provided by the application of the image signal voltage must be greater than the adhesion force (specifically, van der Waals force) between the particles attached to one electrode and the electrode. Or mirror image force) is large, and the particles cannot be drawn away from the electrode and moved to the other electrode. Therefore, a very large operating voltage is required when the display image is transformed.

Therefore, in the display element that further requires the operating voltage of the vibration supply device, the operating voltage is further increased, and if the applied voltage is low, the contrast decreases and display spots occur.

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