# US 2014/0152641 A1 · Electrowetting display apparatus having low power consumption and method of driving the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0152641 A1 - Document ID: US20140152641A1 - Status: Published application - Kind: A1 - Application number: 13/922,405 - Filed: 2013-06-20 - Published: 2014-06-05 - Earliest claimed: 2012-12-03 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Young-jun YUN; Jung Woo KIM; Myoung-hoon JUNG - Web page: https://patentgrep.com/patent/US20140152641A1 ## CPC - G09G 3/348: {based on the deformation of a fluid drop, e.g. electrowetting} - G09G 3/035: {for flexible display surfaces} - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2300/0861: with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes - G09G 2310/061: for resetting or blanking - G09G 2380/02: Flexible displays - G09G: ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION (arrangements for transferring data between digital computers and displays G06F3/14; static indicating arrangements comprising an association of a number of separate sources or light control cells G09F9/00; static indicating arrangements comprising integral associations of a number of light sources H01J, H01K, H10H, H05B33/12; scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission, details thereof H04N1/00) ## Abstract An electrowetting display apparatus includes an electrowetting pixel configured to display an image. The electrowetting pixel includes a polar liquid and a nonpolar liquid arranged between a common electrode and a pixel electrode; and a driving circuit configured to control operations of the electrowetting pixel. The driving circuit includes a memory circuit configured to store an image to be displayed by the electrowetting pixel. The driving circuit is further configured to periodically provide a reset signal to the electrowetting pixel while the electrowetting pixel is displaying the image and provide an image stored in the memory circuit to the electrowetting pixel after the electrowetting pixel cell resets. ## Claims ### Claim 1 An electrowetting display apparatus comprising: an electrowetting pixel configured to display an image, the electrowetting pixel including a polar liquid and a nonpolar liquid arranged between a common electrode and a pixel electrode; and a driving circuit configured to control operations of the electrowetting pixel, the driving circuit including a memory circuit configured to store an image to be displayed by the electrowetting pixel, and the driving circuit further configured to, periodically provide a reset signal to the electrowetting pixel while the electrowetting pixel is displaying the image, and provide an image stored in the memory circuit to the electrowetting pixel after the electrowetting pixel cell resets. ### Claim 2 (depends on 1) The apparatus of claim 1, wherein the driving circuit comprises: a first transistor including a drain connected to a data line and a gate connected to a gate line; a second transistor including a gate connected to a source of the first transistor and a source connected to the pixel electrode of the electrowetting pixel; a capacitor having a first end and a second end, the first end connected to the first transistor and the second transistor and the second end connected to ground; a third transistor including a gate connected to a reset line, a source connected to the pixel electrode and a drain connected to the common electrode; and a fourth transistor including a source connected to a drain of the second transistor such that the fourth transistor is connected to the second transistor in series. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein a gate of the fourth transistor is connected to a reset bar line that is configured to provide a signal opposite to a signal provided to the reset line. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein a drain of the fourth transistor is grounded. ### Claim 5 (depends on 2) The apparatus of claim 2, further comprising: a gate driver configured to generate a gate signal and provide the gate signal to the gate line; a data driver configured to generate an image signal and provide the image signal to the data line; and a clock generator configured to generate a first signal and a second signal, and provide the first signal, as the reset signal, to the reset line and provide the second signal to the reset bar line, the first signal being an inverse of the second signal and the first and second signal having a desired period. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the clock generator is configured to determine the desired period such that the electrowetting pixel receives the reset signal for at least an amount of time required for the nonpolar liquid to return to a state where the nonpolar liquid is evenly spread. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the electrowetting pixel comprises: a rear substrate and a front substrate disposed facing each other; the pixel electrode disposed on a top surface of the rear substrate; a hydrophobic insulating film disposed on the pixel electrode; the nonpolar liquid disposed on the hydrophobic insulating film; the common electrode disposed on a lower surface of the front substrate; and the polar liquid filling a vacant space between the front substrate and the rear substrate. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the front substrate and the rear substrate are transparent substrates. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein the front substrate is a transparent substrate and the rear substrate is a white reflective plate. ### Claim 10 (depends on 7) The apparatus of claim 7, wherein the polar liquid is a transparent liquid and the nonpolar liquid is colored with a color. ### Claim 11 A method of driving an electrowetting display apparatus, the method comprising: displaying an image by an electrowetting pixel by applying a fixed voltage to a common electrode of the electrowetting pixel and applying a variable voltage to a pixel electrode of the electrowetting pixel according to an image signal; storing the image signal in a memory circuit included in a driving circuit of the electrowetting pixel; and resetting, by the driving circuit, the electrowetting pixel by, periodically providing a reset signal from the driving circuit to the electrowetting pixel while the electrowetting pixel is displaying the image, and providing the image signal stored in the memory circuit to the electrowetting pixel after the electrowetting pixel resets. ### Claim 12 (depends on 11) The method of claim 11, wherein the resetting provides the reset signal having a desired period, the desired period determined such that the electrowetting pixel receives the reset signal for at least an amount of time required for a nonpolar liquid included in the electrowetting pixel to return to a state where the nonpolar liquid is evenly spread. ### Claim 13 (depends on 11) The method of claim 11, wherein the resetting resets the electrowetting pixel by periodically providing the reset signal from the driving circuit and the driving circuit includes, a first transistor including a drain connected to a data line and a gate connected to a gate line; a second transistor including a gate connected to a source of the first transistor and a source connected to the pixel electrode of the electrowetting pixel; a capacitor having a first end and a second end, the first end connected to the first transistor and the second transistor and the second end connected to ground; a third transistor including a gate connected to a reset line, a source connected to the pixel electrode and a drain connected to the common electrode; and a fourth transistor including a source connected to a drain of the second transistor such that the fourth transistor is connected to the second transistor in series. ### Claim 14 (depends on 13) The method of claim 13, wherein a source of the fourth transistor is connected to a drain of the second transistor and a gate of the fourth transistor is connected to a reset bar line, and the method further comprises: providing a signal to the reset bar line that is opposite to a signal provided to the reset line. ### Claim 15 (depends on 14) The method of claim 14, wherein the storing the image signal in the memory circuit comprises: storing the image signal in the capacitor by, applying a first voltage to the gate of the first transistor via the gate line, and providing the image signal to the drain of the first transistor via the data line. ### Claim 16 (depends on 15) The method of claim 15, wherein the storing the image signal in the memory circuit further comprises: turning off the third transistor and turning on the fourth transistor while the first voltage is applied to the gate of the first transistor via the gate line, wherein the turning off the third transistor includes applying a second voltage to the gate of the third transistor via the reset line, and the turning on the fourth transistor includes applying the first voltage to the gate of the fourth transistor via the reset bar line, the first voltage being greater than the second voltage. ### Claim 17 (depends on 16) The method of claim 16, wherein the resetting further comprises: resetting the electrowetting pixel by turning off the first transistor, turning on the third transistor and simultaneously turning off the fourth transistor, wherein the turning off the first transistor includes applying the second voltage to the gate of the first transistor via the gate line, the turning on the third transistor includes applying the first voltage to the gate of the third transistor via the reset line, and the turning off the fourth transistor includes applying the second voltage to the gate of the fourth transistor via the reset bar line. ### Claim 18 (depends on 17) The method of claim 17, wherein the providing the image signal further comprises: providing, after the electrowetting pixel resets, the image signal stored in the capacitor to the electrowetting pixel by turning off the third transistor and turning on the fourth transistor, wherein the turning off the third transistor includes applying the second voltage to the gate of the third transistor via the reset line, and the turning on the fourth transistor includes applying the first voltage to the gate of the fourth transistor via the reset bar line. ### Claim 19 (depends on 17) The method of claim 17, wherein the turning on the third transistor and simultaneously turning off the fourth transistor are repeated a number of times within a desired period. ### Claim 20 (depends on 19) The method of claim 19, wherein the turning on the third transistor and simultaneously turning off the fourth transistor are performed by providing, via a clock generator, the reset line and the reset bar line with mutually opposite signals that both having the desired period.