# US 2017/0287397 A1 · Display device correction method and display device correction device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0287397 A1 - Document ID: US20170287397A1 - Status: Published application - Kind: A1 - Application number: 15/507,394 - Filed: 2015-08-27 - Published: 2017-10-05 - Earliest claimed: 2014-09-01 - Assignees: Joled Inc. - Applicants: Joled Inc. - Inventors: Kazuki SAWA; Hiroshi HAYASHI; Tomoyuki MAEDA - Web page: https://patentgrep.com/patent/US20170287397A1 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/2007: {Display of intermediate tones} - G09G 5/363: {Graphics controllers} - G09G 2300/043: Compensation electrodes or other additional electrodes in matrix displays related to distortions or compensation signals, e.g. for modifying TFT threshold voltage in column driver - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G 2360/16: Calculation or use of calculated indices related to luminance levels in display data - 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 A display device correction method performed by a control unit that performs display control on an organic electroluminescent (EL) panel including a plurality of display pixels, in an organic EL display which includes the organic EL panel and the control unit. The display device correction method includes: obtaining a cumulative value of a pixel signal supplied to a drive transistor which is included in a current pixel to be processed among the plurality of display pixels and supplies drive current according to the pixel signal to an organic EL element (OEL); calculating a shift amount of a threshold voltage of the drive transistor, using the cumulative value; calculating an amount of change in mobility, using the shift amount; and calculating a correction parameter for correcting a pixel signal, using the amount of change in mobility. ## Claims ### Claim 1 A display device correction method performed by a control unit that performs display control on a display panel including a plurality of display pixels, in a display device which includes the display panel and the control unit, the display device correction method comprising: obtaining a cumulative value of a pixel signal supplied to a drive transistor which is included in a current pixel to be processed among the plurality of display pixels and supplies drive current according to the pixel signal to a light emitting element; calculating a shift amount of a threshold voltage of the drive transistor, using the cumulative value; calculating an amount of change in mobility, using the shift amount; and calculating a correction parameter for correcting a gradation value of the pixel signal, using the amount of change in mobility. ### Claim 2 (depends on 1) The display device correction method according to claim 1, wherein in the calculating of the amount of change in mobility, the amount of change in mobility is calculated so as to satisfy a relational expression Δμ=C1(ΔVth)γ+C2, where ΔVth denotes the shift amount, and Δμ denotes the amount of change in mobility, and coefficients C1 and γ are each a value calculated in advance using an actual measured value of the amount of change in mobility with respect to the shift amount. ### Claim 3 (depends on 1) The display device correction method according to claim 1, wherein in the calculating of the amount of change in mobility, the amount of change in mobility is calculated using a linear relationship between the amount of change in mobility and the shift amount. ### Claim 4 (depends on 2) The display device correction method according to claim 2, wherein in the calculating of the correction parameter, a gain by which the gradation value is multiplied and an offset value added to the gradation value are each calculated as the correction parameter, and the gain is a value calculated in advance using an actual measured value of the amount of change in mobility with respect to the gain. ### Claim 5 (depends on 2) The display device correction method according to claim 2, wherein in the calculating of the shift amount, the shift amount is calculated so as to satisfy a relational expression ΔVth=A(Vgs−Vth+Voffset)αtβ, where t denotes the cumulative value, and Vgs−Vth denotes a design value of a difference between a gate-source voltage of the drive transistor and the threshold voltage, and coefficients A, Voffset, α, and β are each a value calculated in advance using a graph indicating an actual measured value of the shift amount with respect to the cumulative value. ### Claim 6 A display device correction device, comprising: a display panel including a plurality of display pixels; and a control unit configured to perform display control on the display panel, wherein each of the plurality of display pixels includes a light emitting element, and a drive transistor which supplies drive current according to a pixel signal to the light emitting element, and the control unit is configured to: obtain a cumulative value of the pixel signal supplied to the drive transistor which is included in a current pixel to be processed among the plurality of display pixels; calculate a shift amount of a threshold voltage of the drive transistor, using the cumulative value; calculate an amount of change in mobility, using the shift amount; and calculate a correction parameter for correcting a gradation value of the pixel signal, using the amount of change in mobility. ### Claim 7 (depends on 6) The display device correction device according to claim 6, wherein the drive transistor is an oxide semiconductor element.