Transparent display

Abstract

The present disclosure relates to a method and a pixel architecture for improving the performance of a driving display by having a pixel architecture in which a micro device is located between a driving element and an emission control element. In particular, an array structure of RGB microdevices is discussed.

Description

Technical Field

[0001] The present disclosure generally relates to transparent displays. Summary of the Invention

[0002] The present invention relates to a method for improving the performance of driving a display, the method comprising: having a pixel architecture in which a device is located between a driving element and an emission control element; having a storage element connected to the gate of the driving element; connecting a node of the storage element to a compensation element; connecting the node of the storage element to another node of the driving element or an emissive element; and controlling the programming and storage of a voltage in the storage element via a programming element. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] The foregoing and other advantages of the present disclosure will become apparent upon reading the following detailed description and referring to the accompanying drawings.

[0004] Figure 1A A pixel architecture is shown in which the emissive (or sensor) device is located between a driving element and an emission control element.

[0005] Figure 1B Emission control elements are shown that are shared between pixel circuits in each row and column.

[0006] Figure 1C Embodiments are shown where at least a portion of a pixel is shared between more than one emissive device.

[0007] Although the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the present disclosure is not intended to be limited to the particular forms disclosed. On the contrary, the present disclosure is intended to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. DETAILED DESCRIPTION

[0008] The following description describes a method and architecture for sharing transmit signals and components between multiple rows.

[0009] Micro-LEDs offer small devices compared to pixel size and are well-suited for developing transparent displays. However, a major challenge in transparent displays is using pixel circuits to drive the micro-LED devices.

[0010] The pixel circuit may have multiple components, such as programming switches, storage devices, compensation elements, driving elements and emission elements. Programming allows voltage to be stored in the storage element. The compensation element can be a combination of one or more switches that reduce the effects of non-uniformity, voltage drop or temperature by creating bias conditions. The driving element generates current and drives the micro-LED according to the stored programming voltage. The emission element controls the duty cycle and requires control signals and switches. In order to improve the performance of driving the display, a separate emission control signal can be used for each sub-pixel. This allows the performance of the pixel to be adjusted while achieving peak performance for each sub-pixel. The challenge is that the number of emission signals increases. For example, in the case of RGB, three emission signals will be used.

[0011] One embodiment of the present invention shares emission signals and components between multiple rows. To achieve this, the emission components are moved between the micro-LEDs and one of the power lines, allowing the emission signals and emission components to be shared without interfering with pixel circuit performance.

[0012] Figure 1 shows a pixel diagram where the transmit signal is shared across multiple rows and columns.

[0013] Figure 1A A pixel architecture is shown in which an emissive device (or sensor) 108 is positioned between a driving element 102 and an emission control element 112. Device 108 is a microdevice or micro-LED. Storage element 106 is connected to the gate of the driving element. Another node 140 of the storage element is connected to compensation element 110. This node 140 can be connected to another node of driving element 102 or to emissive element 108. Programming element 104 controls the programming and storage of voltages in storage element 106. Another switch may be positioned between driving element 102 and the V2 potential. The driving element may be a p-type transistor. The comp signal and program signal may be shared and controlled together. During programming time, emissive element 112 is turned off by the EM signal. Emissive element 112 is a transistor, and the EM signal is biased to turn the transistor off. Consequently, emissive device 108 is disconnected from the V1 bias. The comp switch and program switch are turned on, and the Vref and Vdata voltages are applied to storage element 106. After programming is complete, the storage element holds a potential (Vdata-Vref) and applies it to the driver element 102. The driver element converts the potential into a current and drives the emissive device, with the emission switch 112 turned on and the program switch and comp switch turned off. Since the driver element is a transistor, the storage potential is coupled to the gate-source terminals of the driver element.

[0014] In a related embodiment, the transmit switch 112 is movable between the drive element and a potential V2. During programming, the comp switch and the program switch are turned on, and the switch 112 is turned off. The drive element is disconnected from V2, and Vref is set to a bias voltage to ensure that the micro device 108 is off. The switch 112 eliminates any current from Vref to the drive element. As a result, the voltage across the storage element 106 (e.g., a capacitor) is more defined. After the programming cycle, the comp switch 110 and the program switch 104 are turned off, and the switch 112 is turned on. The voltage stored in the storage element 106 controls the current flowing through the drive element 102 of the micro device.

[0015] If one emissive device is used per pixel circuit, node 120 may be shared between pixels in several rows and columns.

[0016] Figure 1B Involved Figure 1A , wherein the emission control element 112 is shared between the individual pixel circuits 100 in each row and column (for Figure 1A : There is a shared functional portion of the pixel circuit 200). Here, the emission portion of the pixel circuit, including the emission switch 112 and the EM signal, is separated from the functional portion 110 (programming and driving) of the pixel circuit described in the previous paragraph. The functional portion includes the programming switch 104 and the comp switch 110, the storage element 106 and the driving element 102. The functional portion 110 can represent an array arrangement of a pixel array. The bias points 120 of the functional portions are connected together and controlled by a single emission portion (EM signal and emission switch 112). During programming of the formed array, the emission portion is turned off by the EM signal and the emission switch 112. When the emission portion is turned off, the programming process described in the previous paragraph is performed on all pixels associated with the array. After the programming cycle, the emission portion can be turned on by the EM signal and the emission switch 112, thereby connecting the formed array to the bias voltage of the functional portion that allows current to flow through the pixels.

[0017] In another related embodiment, the functional portions of the pixel (the programming portion and the driving portion) are shared between more than one emissive device.Here, a separate emission control element 112 is used for each emissive device.

[0018] Figure 1CAn embodiment of a functional pixel portion 200 shared between at least more than one emissive microdevice 108-1, 108-2, or 108-3 is shown. Similar emissive devices in different pixels (in each row and column) share emission control elements 112-1, 112-2, and 112-3 (112 of EM1, EM2, and EM3), and corresponding nodes 120-2, 120-4, and 120-6 can be shared between pixels in several rows and columns. For example, the shared functional portion of the pixel circuit 200 is connected (via 140-1 of 108-1) to a separate red emissive device 108-1, a green emissive device 108-2, and a blue emissive device 108-3. For example, the red emissive devices in adjacent pixels have a shared emission control element 112. Here, the frame is divided into subframes. During the programming cycle of each subframe, all emissive elements are turned off. Programming is performed as described in the previous paragraph.

[0019] After the programming cycle, during each subframe, one emissive element turns on, connecting a group of emissive devices to a bias voltage that allows the current set by the functional portion of the pixel to flow through the microdevices in that group. After programming the next subframe, a different emissive element turns on, connecting a different group of microdevices to the bias voltage. This allows the current from the functional portion of the pixel circuitry to flow through the new group of microdevices.

[0020] While particular embodiments and applications of the present invention have been illustrated and described, it should be understood that the invention is not limited to the precise construction and composition disclosed herein, and that various modifications, changes, and variations will be apparent from the foregoing description without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A method for improving performance of driving a display, the method comprising: having a pixel architecture in which the microdevice is located between a driving element and an emission control element; having a storage element connected to a gate of the driving element; connecting a node of the storage element to a compensation element; connecting the node of the storage element to another node of the driver element or to an emissive element; as well as Programming and storage of voltages in the storage elements are controlled via programming elements. 2 . The method of claim 1 , wherein the emission control elements are shared between pixel circuits in rows and columns. 3 . The method of claim 1 , wherein there is more than one emissive micro device in a circuit, and a separate emission control element is used for each emissive micro device.

4. The method of claim 2, wherein similar emissive micro-devices in different pixels in each row and column share emission control elements. The method of claim 4 , wherein the shared pixel circuitry portion is connected to separate red, green, and blue emissive micro devices.

6. The method of claim 5, wherein the red emissive devices in adjacent pixels have a shared emission control element.

7. The method of claim 1, wherein there is another switch between the driving element and the V2 potential, wherein the driving element is a p-type transistor. The method of claim 7 , wherein the comp signal and the program signal are shared and controlled together.

9. The method of claim 8, wherein during the programming time, the emission element is a transistor, the emission element being turned off as the EM signal is biased to turn off the transistor.

10. The method of claim 9, wherein the emissive micro device is disconnected from V1 bias, and a comp switch and a program switch are turned on, and Vref and Vdata voltages are applied to the storage element.

11. The method of claim 10 , wherein after programming is completed, the storage element maintains a potential (Vdata-Vref) and applies it to the driving element, which converts the potential into a current and drives the emissive microdevice, while the emission switch is turned on and the program switch and the comp switch are turned off. 12 . The method of claim 11 , wherein the driving element is a transistor, and a storage potential is coupled to a gate-source terminal of the driving element.

13. The method of claim 1, wherein an emission switch moves between the drive element and a potential V2, wherein further, during programming, a comp switch and a program switch are turned on, and the emission switch is turned off.

14. The method of claim 13, wherein the driving element is disconnected from V2 and a potential Vref is set to bias the micro device to turn off, so that the emission switch eliminates any current from Vref to the driving element.

15. The method according to claim 14, wherein after programming is completed, the comp switch and the program switch are turned off, and the emission switch is turned on, wherein further, the voltage stored in the storage element controls the current of the driving element flowing through the micro device.

16. The method of claim 1, wherein the emission control elements are shared between pixel circuits in rows and columns.

17. The method of claim 16, wherein an emission portion of the pixel circuit including the emission switch and EM signal is separated from a functional portion including programming and comp switches, a storage element, and a drive element.

18. The method of claim 17, wherein the functional portions are arranged in an array representing a pixel array.

19. The method of claim 18, wherein a bias point of a functional portion is connected and controlled by the EM signal and the transmit switch.

20. The method of claim 19 , wherein during the programming of the array, the emission portion is turned off by the EM signal and the emission switch; while the emission portion is turned off, the programming process described in the previous paragraph is performed on all of the pixels associated with the array; after the programming cycle, the emission portion can be turned on by the EM signal and the emission switch 112, thereby connecting the formed array to a bias voltage that allows current to flow through the functional portion of the pixels.

21. The method of claim 20, wherein a programming process is performed on all of the pixels associated with the array when the emissive portion is off.

22. The method of claim 21, wherein after the programming process, the emission portion is turned on by the EM signal and the emission switch, thereby connecting the array to a bias voltage that allows current to flow through the functional portion of the pixel.

23. The method of claim 1, wherein the functional portions of the pixel, including the programming portion and the driving portion, are shared between more than one emissive microdevice, wherein further, a separate emission control element is used for each emissive microdevice.

24. The method of claim 23, wherein the shared functional portion is connected to separate red, green, and blue emitting micro devices.

25. The method of claim 24, wherein the red emissive micro devices in adjacent pixels have a shared emission control element, wherein a frame is divided into sub-frames.

26. The method of claim 25, wherein during the programming period of each subframe, all of the transmitting elements are turned off.

27. A method according to claim 26, wherein after the programming cycle, during each subframe, an emissive element is turned on, thereby connecting a group of emissive microdevices to a bias voltage, which allows a current set by the functional part of the pixel to flow through the microdevices in the group of microdevices.

28. A method according to claim 27, wherein after programming the next subframe, different emissive elements are turned on, thereby connecting a different set of microdevices to the bias voltage, which allows the current from the functional part of the pixel circuit to flow through the new set of microdevices.

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