Electrowetting　Display（EWD）not　only　has　the　advantages　of　ultra-low　power　consumption，can　reading　under　strong　light，paper-like　reading　experience，but　also　has　the　advantages　of　high　response　speed　and　video　playback　that　Electronic　Paper　Displays（EPD）does　not　have.　However，problems　such　as　oil　splitting，oil　backflow，charge　trapping，hysteresis　effect，hinder　the　development　of　EWD.　Hysteresis　is　an　important　reason　for　the　gray　distortion　of　EWD.　Aiming　at　the　phenomenon　that　the　luminance　displayed　by　the　same　driving　voltage　is　different　in　the　voltage　rise　stage　and　the　voltage　drop　stage　due　to　the　hysteresis　characteristics　of　EWD，this　paper　proposes　a　gray　distortion　correction　method　for　the　hysteresis　characteristics　of　electrowetting　display.　Firstly，we　designed　and　built　a　test　platform.　The　test　platform　is　used　to　measure　the　change　of　EWD　aperture　ratio　under　different　voltages.　The　test　platform　consists　of　a　microscope（with　a　high-speed　CCD　camera），a　function　generator，a　power　amplifier，and　a　PC.　At　the　same　time，we　developed　a　program　to　measure　the　aperture　ratio　with　Labview，which　was　run　on　PC.　Part　of　the　function　of　the　program　is　to　output　test　voltage.　This　function　uses　PC　as　the　master　computer　and　function　generator　as　the　slave　computer，and　uses　SPCI　to　communicate　between　them.　The　output　voltage　of　the　function　generator　is　amplified　by　the　power　amplifier　and　then　applied　to　the　EWD.　The　second　part　of　the　program　is　to　detect　the　degree　of　ink　shrinkage.　This　function　uses　PC　as　the　master　computer　and　microscope　with　camera　as　the　slave　computer.　When　the　voltage　is　applied　to　the　EWD，the　ink　begins　to　shrink，and　the　camera　collects　the　ink　status　in　the　form　of　image　data　and　sends　it　back　to　the　master　computer.　The　last　part　of　the　program　is　to　calculate　the　aperture　ratio　with　Matlab.　After　the　image　data　is　collected　and　transmitted　to　Matlab，the　image　is　processed　by　using　the　program　we　wrote　in　advance　in　Matlab.　The　corresponding　aperture　ratio　at　that　applied　voltage　will　be　calculated　and　saved.　Secondly，the　influence　of　hysteresis　characteristics　on　the　photoelectric　curve　was　measured　at　different　voltage　range.　The　lowest　driving　voltage　of　EWD，above　which　the　ink　begins　to　shrink，and　the　highest　driving　voltage，above　which　the　ink　will　cross　the　pixel　wall，are　used　as　the　measurement　boundary.　The　measured　aperture　ratio　data　is　used　as　the　basis　for　curve　fitting，and　quadratic　polynomial　is　used　for　curve　fitting.　The　correction　methods　is　designed　based　on　the　obtained　curves.　The　main　correction　methods　are　as　follows：when　the　image　data　enters，it　is　converted　to　the　corresponding　gray　scale　and　the　aperture　ratio.　The　initiation　voltage　is　determined　according　to　the　changing　trend　of　the　image　data　According　to　the　difference　of　starting　voltage，select　the　appropriate　fitting　curve，calculate　the　corrected　driving　voltage，achieve　the　correct　luminance.　The　judging　method　of　the　initiation　voltage　is　as　follows：when　the　three　consecutive　frames　of　image　data　have　a　increasing-decreasing　or　increasing-decreasing　change，the　initiation　voltage　is　the　knee-point　voltage，and　vice　versa.　Finally，we　use　the　luminance　meter　to　measure　the　luminance　in　the　darkroom　environment.　The　experimental　results　show　that　the　actual　luminance　of　each　gray　scale　will　be　affected　by　the　electrowetting　hysteresis　characteristics，and　there　is　a　significant　difference　between　the　voltage　rising　stage　and　the　voltage　dropping　stage.　The　maximum　relative　luminance　difference　can　reach　20.43%.　After　correction　by　the　proposed　correction　method，the　relative　luminance　difference　of　gray　scale　decreases　from　20.07%　to　0.01%，with　a　reduction　ratio　of　99.93%.　The　relative　luminance　difference　decreased　by　10.84%　on　average，and　the　reduction　ratio　was　80.98%.　The　highest　degree　of　aperture　ratio　distortion　was　reduced　from　5.67%　to　0.13%，with　the　reduction　ratio　was　97.7%.　On　the　other　hand，using　human　eyes　to　observe　the　correction　results，it　can　be　found　that　the　actual　display　effect　after　correction　is　significantly　improved　compared　with　that　before　correction.　©　2024　Chinese　Optical　Society.　All　rights　reserved.