Method of driving a display device

• US 5,233,340 A
• Filed: 06/19/1992
• Issued: 08/03/1993
• Est. Priority Date: 09/16/1989
• Status: Expired due to Term

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Yamaguchi, Hisashi, Shoji, Kazuo, Yamamoto, Kioichi, Sakamoto, Atsushi, Ohba, Toshihiro, Uede, Hisashi
• Primary Examiner(s): Oberley, Alvin E.
• Assistant Examiner(s): WU, XIAO MIN
• Application Number:
  US07/900,754
• Time in Patent Office: 410 Days
• Field of Search: 340/793, 340/781, 340/767, 340/805, 340/811, 340/825.81, 315/169.3
• US Class Current: 345/690
• CPC Class Codes: G09G 3/30 using electroluminescent panels

Abstract

A method of driving a display device with a plurality of scanning side electrodes and a plurality of data side electrodes which are disposed in directions intersecting each other, and a dielectric layer interposed between the scanning side electrodes and the data side electrodes, and including steps of applying modulation voltages corresponding to display data to the data side electrodes, and also applying writing voltages of positive or negative polarity to the scanning side electrodes through line sequence, so as to cause picture elements composed of the dielectric layer to emit light. The driving method further includes steps of thinning out the display data, and applying a plurality of kinds of modulation voltages different in amplitude according to each frame, so as to cause the picture elements to effect gradation display of different brightness in multi-stages.

Claims

1. A method of driving a display device with a plurality of scanning side electrodes and a plurality of data side electrodes which are disposed in directions intersecting each other, and a dielectric layer means interposed between said scanning side electrodes and said data side electrode, and including steps of applying plural frames per drive cycle of modulation voltages corresponding to display data to said data side electrodes, and also applying plural frames per drive cycle of writing voltages of positive or negative polarity to said scanning side electrodes through line sequencing, so as to cause picture elements composed of said dielectric layer means to emit light in response to an applied voltage which is higher than a light emitting threshold voltage,

said driving method further comprising steps of thinning out the display data by selecting the number of frames to be impressed in one drive cycle with the applied voltages higher than said threshold voltage, applying a plurality of kinds of modulation voltages which are different in amplitude in each frame, wherein said voltages applied to said picture elements are different in each frame when the number of frames selected to be impressed in one cycle with applied voltages higher than said threshold voltage includes each frame, thereby to cause the picture elements to effect gradation display of a number of different brightnesses in multi-stages and wherein the number of said plural number of frames per drive cycle do not correspond to said number of different brightnesses.

2. A method as in claim 1 wherein said different amplitude signals are applied in the respective frames and said voltage applied to said picture elements is equivalent to the difference between said applied modulation voltages and said writing voltages.

3. A method as in claim 2 wherein said writing voltages are Vw1 or -Vw2, said modulation voltages are OV, a voltage of a set amplitude greater than OV and less than V_M, V_M, Vw1=Vw2+V_M, and said threshold voltage is greater than or equal to Vw2 but less than or equal to Vw1.

4. A method as in claim 3 wherein said picture elements are caused to effect gradation display in three or more levels of brightness.

5. A method of cyclically driving a display device, said device including plural scanning side electrodes, plural data side electrodes disposed in directions intersecting said scanning side electrodes, a dielectric layer means interposed between said scanning side and said data side electrodes, and picture elements composed of said dielectric layer means interposed between said scanning side and said data side electrodes for emitting light in response to an applied voltage which is higher than or equal to a threshold voltage V_th, said method comprising:

applying plural frames of modulation voltages OV, a voltage of a set amplitude greater than OV and less than V_M, or V_M to said data side electrodes for each driving cycle, wherein said modulation voltages are different in amplitude in each of said plural frames and correspond to the display data;

applying plural frames of positive or negative writing voltages, Vw1 or -Vw2 respectively, to said scanning side electrodes, wherein Vw1=Vw2+V_M and V_th is greater than or equal to Vw2 but less than or equal to Vw1,

whereby said picture elements are caused to obtain gradation display of at least three brightness levels by applying plural frames of modulation and writing voltages for each drive cycle that are each lesser in number than the number of brightness levels obtained.