# US 12,002,427 B2 · Projection device and method for controlling projection device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,002,427 B2 - Document ID: US12002427B2 - Status: Granted - Kind: B2 - Application number: 18/153,819 - Filed: 2023-01-12 - Published: 2023-07-13 - Granted: 2024-06-04 - Earliest claimed: 2022-01-13 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Yoichi Momose - Web page: https://patentgrep.com/patent/US12002427B2 ## CPC - G09G 3/3233: with pixel circuitry controlling the current through the light-emitting element - G09G 3/002: {to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT} - G09G 3/2003: {Display of colours (specific for liquid crystal displays G09G3/3607)} - H04N 9/3138: {using arrays of modulated light sources (electroluminescent display devices G09G3/30)} - H04N 9/3188: {Scale or resolution adjustment (scaling in general G06T3/40; resolution modifying circuits for displays in general G09G5/391)} - G09G 2300/0814: used for selection purposes, e.g. logical AND for partial update - G09G 2300/0819: used for counteracting undesired variations, e.g. feedback or autozeroing - G09G 2300/0852: being a dynamic memory with more than one capacitor - G09G 2300/0871: with level shifting - G09G 2310/08: Details of timing specific for flat panels, other than clock recovery - G09G 2320/0233: Improving the luminance or brightness uniformity across the screen - G09G 2340/0407: Resolution change, inclusive of the use of different resolutions for different screen areas - 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) - H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION ## Abstract In a pixel circuit including a first capacitance element and a second capacitance element, in a writing sub-frame, a voltage corresponding to a gray scale level is held in a first capacitance element, a plurality of OLEDs are off in a vertical scanning line flyback period after the writing sub-frame, and in a light-emitting sub-frame after the vertical scanning line flyback period, a current corresponding to the voltage held in the first capacitance element is supplied to the OLED, and the voltage corresponding to the gray scale level is held in the second capacitance element. In an optical path shifting element, an optical path is shifted in the vertical scanning line flyback period, and in the light-emitting sub-frame, the optical path is stabilized. ## Claims ### Claim 1 A projection device, comprising: a display panel including a pixel circuit including a first capacitance element and a second capacitance element, and a light-emitting element that emits light, having luminance corresponding to a current, in a predetermined direction, wherein in a first period, a voltage corresponding to a current supplied to the light-emitting element is held in the first capacitance element, in a light-out period after the first period, the light-emitting element is off, in a second period after the light-out period, a current corresponding to the voltage held in the first capacitance element is supplied to the light-emitting element, and a voltage corresponding to the current supplied to the light-emitting element is held in the second capacitance element; and an optical path shifting element configured to shift an optical path of light emitted from the light-emitting element to a first and second optical paths, wherein shifting is performed from the first optical path to the second optical path in the light-out period, and the second optical path is maintained in the second period. ### Claim 2 (depends on 1) The projection device according to claim 1, wherein in the first period, a current corresponding to the voltage held in the second capacitance element is supplied to the light-emitting element, and the first optical path is maintained. ### Claim 3 (depends on 2) The projection device according to claim 2, wherein the pixel circuit is provided corresponding to an intersection of a data line and a scanning line, and further includes a first selector, a second selector, and a driving transistor, the driving transistor is configured to supply a current corresponding to a voltage of a gate node to the light-emitting element, in the first period, the first selector electrically connects one end of the first capacitance element to the data line when the scanning line is selected, the second selector electrically connects one end of the second capacitance element to the gate node, in the second period, the first selector electrically connects the one end of the second capacitance element to the data line when the scanning line is selected, and the second selector electrically connects the one end of the first capacitance element to the gate node. ### Claim 4 (depends on 3) The projection device according to claim 3, wherein the first selector includes a first switching element that is in an on state or an off state between the data line and the one end of the first capacitance element, and a second switching element that is in the on state or the off state between the data line and the one end of the second capacitance element, and the second selector includes a third switching element that is in the on state or the off state between the one end of the first capacitance element and the gate node, and a fourth switching element that is in the on state or the off state between the one end of the second capacitance element and the gate node. ### Claim 5 (depends on 4) The projection device according to claim 4, wherein the pixel circuit includes a fifth switching element connected in series to the driving transistor between a high level power supply wiring line and a low level power supply wiring line. ### Claim 6 (depends on 5) The projection device according to claim 5, wherein in all or a part of the first period or the second period, the fifth switching element is in the on state. ### Claim 7 (depends on 3) The projection device according to claim 3, wherein the pixel circuit includes a sixth switching element that brings the driving transistor into a diode-connected state. ### Claim 8 (depends on 7) The projection device according to claim 7, wherein the pixel circuit includes a third capacitance element in which a threshold voltage of the driving transistor is held, and the third capacitance element is interposed between the one end of second capacitance element and the gate node in the first period and is interposed between the one end of the second capacitance element and the gate node in the second period. ### Claim 9 A method for controlling a projection device including a display panel including a pixel circuit including a first capacitance element and a second capacitance element, and a light-emitting element that emits light, having luminance corresponding to a current, in a predetermined direction, and an optical path shifting element configured to shift an optical path of light emitted from the light-emitting element to a first optical path and a second optical path, wherein in a first period, a voltage corresponding to a current supplied to the light-emitting element is held in the first capacitance element, in a light-out period after the first period, the light-emitting element is off, and the optical path is shifted from the first optical path to the second optical path, in a second period after the light-out period, a current corresponding to the voltage held in the first capacitance element is supplied to the light-emitting element, a voltage corresponding to the current supplied to the light-emitting element is held in the second capacitance element, and the second optical path is maintained.