WO2021045754A1

WO2021045754A1 - Amoled panel having different subpixel circuit configurations

Info

Publication number: WO2021045754A1
Application number: PCT/US2019/049603
Authority: WO
Inventors: Sangmoo Choi; Sun-Il Chang; Jyothi KARRI; Ion Bita
Original assignee: Google Llc
Priority date: 2019-09-04
Filing date: 2019-09-04
Publication date: 2021-03-11

Abstract

A device is described that has different circuit configurations for subpixel circuits of subpixels in low pixel density region and high pixel density region of an active matrix organic light emitting diode (AMOLED) panel of the device to match brightness of the low pixel density region and the high pixel density region.

Description

AMOLED PANEL HAVING DIFFERENT SUBPIXEL CIRCUIT CONFIGURATIONS

TECHNICAL FIELD

[0001] The subject matter described herein relates to a device implementing different circuit configurations for subpixel circuits of subpixels in low pixel density region and high pixel density region of an active matrix organic light emitting diode (AMOLED) display panel to match brightness of the low pixel density region and the high pixel density region.

BACKGROUND

[0002] Conventional organic light emitting diode (OLED) display panels feature an array of separately addressable pixels that can emit different levels of light to dynamically display images. Each pixel can have two or more subpixels (e.g., red, green, and blue subpixels), each of which includes an OLED that is associated with a corresponding subpixel circuit. Traditionally, each subpixel circuit for an OLED of the same color throughout the display panel is completely or substantially identical. Such identical nature causes each subpixel circuit to provide the associated OLED with the same, or substantially the same, amount of emission current in accordance with the same data voltage, which causes each OLED of the same color to emit light brightening the panel region associated with that subpixel. Accordingly, where each subpixel features the same type of pixel circuit providing the same level of emission current, the display’s brightness can vary in the event that the density of the pixels varies across the panel. SUMMARY

[0003] Certain organic light emitting diode (OLED) display panels have different pixel densities in various regions of the display panel. For example, the density of pixels may be lower in regions where sensors are located, and higher in other regions. However, where the pixel circuit associated with each pixel (or subpixel) is designed to provide the same or substantially same emission current to the corresponding OLED, the pixel density variation can undesirably brighten regions having a high pixel density significantly more than regions having a low pixel density, thereby undesirably rendering different brightness in different regions of the display panel.

[0004] Devices are described that implement different circuit configurations for subpixel circuits of subpixels in low pixel density region and high pixel density region of an active matrix organic light emitting diode (AMOLED) panel. The different circuit configurations allow the display to match brightness of the low pixel density region and the high pixel density region. Related systems, apparatuses, articles, methods, and/or non-transitory computer programmable products are also within the scope of this disclosure.

[0005] In one aspect, a device is described that has includes an organic light emitting diode (OLED) display panel, display driver integrated circuits, and signal lines. The OLED panel includes a first region of first pixels having a first pixel density, and a second region of second pixels having a second pixel density that is less than the first pixel density. Each first pixel includes one or more subpixels, each of which includes a corresponding OLED configured to emit light of a first color and a corresponding first subpixel circuit associated with the OLED. Each second pixel includes one or more subpixels each comprising a corresponding OLED configured to emit light of the first color and a corresponding second subpixel circuit associated with the OLED. The signal lines electrically connect each subpixel with the display driver integrated circuits. The signal lines include data lines providing a data voltage to each subpixel during operation of the device. The first and second subpixel circuits and display driver integrated circuits are configured so that a brightness of the display in the first and second regions is substantially uniform when the subpixels in the first and second regions are addressed with the same data voltage.

[0006] In some variations, one or more of the following can additionally be implemented either individually or in any feasible combination. The first and second subpixel circuits have a common arrangement of one or more transistors and one or more capacitors. The arrangement includes a first capacitor. The first capacitor in the second subpixel circuit has a higher capacitance than the first capacitor in the first subpixel circuit.

[0007] The first and second subpixel circuits have a common arrangement of one or more transistors and one or more capacitors. The arrangement includes a first transistor. The first transistor in the second subpixel circuit has a larger aspect ratio than the first transistor in the first subpixel circuit.

[0008] The signal lines include a set of first signal lines supplying a pixel emission supply voltage to each subpixel circuit. The display driver integrated circuits are configured to apply a higher pixel emission supply voltage to the second subpixel circuits than the first subpixel circuits.

[0009] The signal lines include a second set of signal lines supplying an initialization voltage to each subpixel circuit and the display driver integrated circuits are configured to apply a lower initialization voltage to the second subpixel circuits than the first subpixel circuits. The initialization voltage is a voltage that initializes a gate electrode of a first transistor of a corresponding subpixel circuit.

[0010] Each pixel includes two or more subpixels, each of which is configured to emit light of a different color. The first color is red, green, or blue. An area of the first region is larger than an area of the second region. The second region is located at an edge of the display panel.

[0011] The device further includes a sensor arranged behind the display panel and configured to sense electromagnetic radiation transmitted through the second region of the display panel. The sensor can be a camera. The sensor can be a facial recognition sensor. The OLED display can be an active matrix OLED display. The device can be a smartphone or a tablet computer. Each first subpixel circuit and each second subpixel circuit comprises a total of seven transistors and one capacitor.

[0012] The implementations discussed above can be advantageous. For example, the specific variation in subpixel circuits for regions with different pixel densities can result in uniform brightness throughout the AMOLED panel.

[0013] The details of one or more implementations are set forth below. Other features and advantages of the subject matter will be apparent from the detailed description, the accompanying drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a plan view of an example device having a display panel including a region having a higher density of pixels and another region having a lower density of pixels, in accordance with some implementations consistent with the present subject matter.

[0015] FIGS. 2A-2C are schematic diagrams illustrating examples of pixel clusters. [0016] FIG. 3A is an example of a circuit diagram of a subpixel circuit of a subpixel.

[0017] FIG. 3B is a plot showing an example of relative timing of SCAN signals and an EM signal for the subpixel circuit shown in FIG. 3A.

[0018] FIG. 4A is a plan view of another device that includes another example of a display panel including a region having a higher density of pixels and two other regions having lower densities of pixels.

[0019] FIG. 4B is a plan view of a device that is divided into two regions with substantially equal areas for a higher pixel density region and a lower pixel density region.

[0020] Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

[0021] FIG. 1 illustrates an example device 100 (e.g., a smartphone) having a display panel 102 including a region 104 having a first density of pixels 106 (e.g., 100 pixels per inch (PPI) or more, 200 PPI or more, 300 PPI or more) and another region 108 at the top of the display panel having a second density of pixels 110 (e.g., 50 PPI or more, 100 PPI or more, 200 PPI or more). The second pixel density 110 is lower than the first pixel density 106. For example, the pixel density 106 can be 20% or more (e.g., 50% or more, 80% or more, 100% or more) greater than pixel density 110.

[0022] Each pixel can include two or more subpixels (e.g., three subpixels, such as a red subpixel, a green subpixel, and a blue subpixel), as explained below with reference to FIGS. 2A-2C. Each subpixel has a corresponding subpixel circuit, an example of which is described below with reference to FIG. 3A-3B. The configuration of the subpixel circuit shown in FIG. 3 A is varied between region 104 and region 108, as further explained below. Such variation matches brightness of the region 108 with low pixel density 110 and the region 104 with high pixel density 106, thereby making the brightness of the entire display panel 102 uniform. The location of the region with low density of pixels can vary in other examples of display panels, examples of which are described below with reference to FIGS. 4A and 4B.

[0023] The subpixel circuit for each same-colored subpixel within the first region 104 can be the same. The subpixel circuit for each same-colored subpixel within the second region 108 can be the same. However, the subpixel circuit for a subpixel with a particular color within the region 108 is varied from the subpixel circuit for the subpixel with that particular color within the region 104, as explained below with reference to FIG. 3A.

[0024] At least one sensor 112 is placed underneath the region 108 where the pixel density is lower than the rest of the area 104. The at least one sensor 112 can be an image sensor (including a camera), a proximity sensor, an ambient light sensor, an accelerometer, a gyrometer, a magnetometer, a fingerprint sensor, a barometer, a Hall effect sensor, a facial recognition sensor, any other one or more sensors, and/or any combination thereof. Sensor 112 can be a front facing sensor, detecting electromagnetic radiation transmitted through display panel 102 at region 108.

[0025] The device 100 can be a mobile device, such as a phone, a tablet computer, a phablet computer, a laptop computer, a wearable device such as a smartwatch, a digital camera, any other one or more mobile device, and/or the like.

In alternate implementations, the device 100 can be any other computing device such as a desktop computer, a kiosk computer, a television, and/or any other one or more computing devices that are configured to output visual data. In some implementations, the device can be referred to as a computing device or a communications device.

[0026] The display panel 102 is an organic light emitting diode (OLED) panel. The OLED display is driven with an active matrix display scheme, and the OLED display can be referred to as an active matrix organic light emitting diode (AMOLED) panel. The active matrix display scheme can be advantageous over a passive matrix display scheme in a passive matrix organic light emitting diode (PMOLED) panel, as AMOLED panels can provide higher refresh rates, higher resolution, higher luminance than PMOLED panels, and consume significantly less power than PMOLED panels.

[0027] In general, the first and second pixel densities are selected to provide a high-resolution image in at least the region 104 and to enable sensor 112 to perform appropriately. In certain implementations, first density of pixels 106 is 100 pixels per inch (PPI) or more, (e.g., 200 PPI or more, 300 PPI or more, 500 PPI or more). In some implementations, second density of pixels 110 is 50 PPI or more (e.g., 100 PPI or more, 200 PPI or more). In one example, the density 110 can be 200 pixels per inch, and the density 106 can be 300 pixels per inch. In another example, the density 110 can be 75 pixels per inch, and the density 106 can be 250 pixels per inch. In yet another example, the density 110 can have any value between 75 pixels per inch and 225 pixels per inch, and the density 106 can have any value between 225 pixels per inch and 800 pixels per inch.

[0028] The region 108 can be toward an upper portion (e.g., toward the top) of the display panel 102. In an alternate implementation, the region 108 can be located at any other location on the display panel 102. The area occupied by the region 108 can be less than the area occupied by the region 104. In certain examples, the area occupied by the region 108 can be between 5% and 10% of the area occupied by the region 104. In some examples, the area occupied by the region 108 can be between 2% and 20% of the area occupied by the region 104. In general, region 108 is sufficiently large to facilitate satisfactory operation of sensor 112, e.g., where the sensor is a front-facing camera or facial recognition sensor.

[0029] Status symbols — such as the symbols for data saver mode, mobile network standard (e.g., LTE, which stands for long term evolution standard for broadband communication, 5G, 4G, and/or any other standard), Wi-Fi, status (e.g., launched or testing) of mobile network, connection speed, lack of cellular data, activation of a virtual assistant, capture of a screenshot, activation of keypad, activation of teletypewriter, activation of any other feature of a phone, any other one or more symbols, amount of battery remaining, and/or any combination thereof — can be displayed in the region 108. In an alternate implementation, such status symbols can be displayed in the region 104.

[0030] In general, subpixels can be arranged in pixels in a variety of geometries. Pixels can also be clustered together to form pixel clusters. FIGS. 2A- 2C show three examples 202, 206, and 208 of pixel clusters. The pixel cluster 202 has one pixel 202p. The pixel 202p has three subpixels — a red subpixel 202r, a green subpixel 202g, and a blue subpixel 202b. Pixel cluster 206 has two pixels 206pl and 206p2, each of which has two subpixels. Namely, pixel 206pl has a red subpixel 206r and a green subpixel 206g. Pixel 206p2 has a blue subpixel 206b and a green subpixel 206g. Pixel cluster 208 has four pixels 208pl, 208p2, 208p3, and 208p4. Each pixel has two subpixels. Specifically, each pixel has a green subpixel 208g, while pixels 208pl and 208p4 both have red subpixels 208r and pixels 208p2 and 208p3 both have blue subpixels 208b.

[0031] In the low pixel density region 108, pixel clusters that are described above can be more sparsely located than the high pixel density region 104, in turn, the aperture between pixel clusters enables more electromagnetic radiation pass through the display panel 102 from/to the sensors behind that display panel 102.

[0032] Although a pixel cluster is described above as having two or four pixels, in alternate implementations a pixel cluster can have any other number (e.g., three, five, six, seven, eight, or any other integer) of pixels. While the colors of the subpixels have been described as red, green or blue, in other implementations other colors are also possible, such as violet, indigo, yellow, orange, and any other color, and/or any combination thereof.

[0033] Each subpixel has a corresponding subpixel circuit, one example of which shown in the circuit diagram in FIG. 3A. Generally, each subpixel circuit includes an OLED which is actively addressed by the pixel circuit. This means that the sub-pixel circuit actively maintains the emission state of the sub-pixel while the display driver circuits address (e.g., switches emission states of) other sub-pixels. Accordingly, the OLED panel may be referred to as an active matrix organic light emitting diode (AMOLED) panel. A display driver circuit is an integrated circuit that provides an interface between the OLED panel and a microprocessor.

[0034] The subpixel circuit for each same-colored subpixel within the first region 104 can be the same (or, in other implementations, similar or substantially the same). Alternatively, or additionally, the subpixel circuit for each same-colored subpixel within the second region 108 can be the same (or, in other implementations, similar or substantially the same). The subpixel circuit for a subpixel with a particular color within the first region 104 can however be different from the subpixel with that particular color within the second region 106, as explained below with respect to FIG. 3A.

[0035] FIG. 3A illustrates an example of a subpixel circuit 302 of a subpixel. The subpixel circuit 302 for each same-colored subpixel in the region 104 is same or substantially similar. The subpixel circuit is addressed by several signal lines. SCAN lines and EM signal lines are horizontally placed signal lines for each row of pixels. The signals that are transmitted by these lines are typically generated by the panel-integrated driver circuits on left/right edge of the display. The DATA line is vertically placed line for column data voltages which is generated by a display column driver IC.

[0036] The subpixel circuit 302 includes an OLED. Subpixel circuit 302 further includes seven transistors Tl, T2, T3, T4, T5, T6 and T7, and a capacitor Cl. The OLED has a parasitic capacitance, denoted in the circuit diagram as C2. Tl can also be referred to as a first transistor, T2 can also be referred to as a second transistor, T3 can also be referred to as a third transistor, T4 can also be referred to as a fourth transistor, T5 can also be referred to as a fifth transistor, T6 can also be referred to as a sixth transistor, and T7 can also be referred to as a seventh transistor. Cl can also be referred to as a first capacitor, and C2 can also be referred to as a second capacitor.

[0037] Further, in the subpixel circuit 302, the voltage VINIT refers to the initiation voltage that is applied to the subpixel circuit 302 to initialize the gate electrode of transistor Tl of the subpixel circuit 302 prior to the pixel circuit 302 receives a new voltage data from a column driver IC through the DATA line. Typically, VINIT is the same for each subpixel circuit in the same region (104 or 108). The voltage level of VINIT, an initialization voltage, is sufficiently lower than the new data voltage from the column driver IC through DATA lines, DATA[k] Otherwise, depending on the voltage level at the gate electrode of transistor Tl, transistor T1 may not be turned on, in turn, transistor Tl blocks the signal path from the DATA lines, DATA[k] to the gate electrode of Tl. Generally, the data voltage can be different for each subpixel circuit in order to reproduce an image using the display. The VINIT also initializes the anode of the OLED when transistor T7 is turned on by SCAN[n] signal. The pixel emission supply voltage (also referred to as voltage VDD) refers to a positive voltage provided by a power supply (not shown) to the pixel circuit 302 and the display panel 102. The voltage VDD provides a reference level for a data voltage, in that, the OLED emission current in a subpixel, which is generated by a subpixel circuit, is determined by the relative voltage difference between VDD and the programmed voltage at the gate electrode of transistor Tl . The voltage VDD also supplies the OLED emission current in a subpixel circuit once the OLED current level is determined by the subpixel circuit. The voltage Vss refers to a negative power source (not shown) to be connected to the cathode of OLEDs in an AMOLED display panel 102. In some implementations, the voltage Vss can be a positive voltage but having lower potential than VDD. In certain implementations, the voltage Vss can be ground voltage (e.g., zero volts). The DATA[k] line provides data voltage to each pixel in the k^lh column of pixels in the display panel 102.

[0038] In the subpixel circuit 302, a voltage at the gate of each transistor of the transistors T1-T7 can control a current between the source of that transistor and drain of that transistor. The voltage at the gates of the transistors T5 and T6 is controlled by an n^th row line light emission control line EM[n] The voltage at the gates of transistors T2, T3 and T7 is controlled by the n^th scan line SCAN[n] The voltage at the gates of the transistor T4 is controlled by the (n-l)^th scan line SCAN[n- 1] The transistors T5 and T6 are turned off when corresponding EM[n] signal is high, making the pixel circuit stop supplying the OLED emission current to the corresponding OLED, since the transistors are p-channel field effect transistors, and the pixel circuit becomes ready to receive new data voltage for next image on the screen. While T5 and T6 are turned off, SCAN[n-l] which represents the SCAN signal of the n-l* row line, turns on T4, and the gate electrode of T1 is initialized to a voltage VINIT. Once SCAN[n-l] goes high, and turns off T4, SCAN[n], which is the SCAN signal for n^th row line, turns on T2, T3, and T7, and the gate electrode of T1 is charged to threshold voltage compensated data voltage by the diode connected T1 in the circuit, and, at the same time, the anode of the OLED is initialized to VINIT. In some cases, T7 can be controlled by signals other than SCAN[n] as long as T7 is turned on and turned back to off again while EM[n] is high. The relative pulse timing of signals applied using EM[n], SCAN[n], and SCAN[n-l] is shown in FIG. 3B.

[0039] The configuration of the subpixel circuit 302 is varied between region 104 and region 108 to match brightness of the region 108 with low pixel density 110 and the region 104 with high pixel density 106, thereby making the brightness of the entire display panel 102 uniform. More specifically, with respect to the subpixel circuit 302 for the subpixels in the region 104, one or more of the following changes can be made to the subpixel circuit 302 for the subpixels in the region 108: (a) the capacitor Cl for a subpixel in the region 108 can be configured to have a greater (e.g., 10% or more higher, 20% or more, higher, 50% or more higher, double or more) capacitance than the capacitor Cl for a same-colored subpixel in the region 104, (b) the transistor T1 for a subpixel in the region 108 can be configured to have a larger (e.g., 10% or more higher, 20% or more, higher, 50% or more higher, double or more, triple or more) aspect ratio (i.e., W/L) than that of the transistor T1 in the region 104, (c) the voltage VINIT for a subpixel in the region 108 can be lower (e.g., 0.5 V or more lower, 1 V or more lower, 2 V or more lower) than the voltage for initializing the subpixel circuit in the region 104, and (d) the VDD in the region 108 can be higher (e.g., e.g., 0.5 V or more higher, 1 V or more, higher, 2 V or more higher) than VDD in the region 104. Any of above four configuration can be combined together.

[0040] Such differences in the subpixel circuits of the regions 104 and 108 enable the region 108 with lower density 110 of pixels to emit same or similar (e.g., within 10%) brightness as the region 104 with a higher density 106 of pixels, as per the following. Any of the changes (a), (b), (c), or (d) as noted above, can result, for a same value of data voltage, VDATA for same-colored subpixels in regions 104 and 108, in a higher emission current — i.e., current generated in the subpixel circuit, then flowing to the cathode of the OLED through the anode and OLED of the subpixel — in the subpixel circuit 302 in the region 108 than the emission current in the subpixel circuit 302 of a same-colored subpixel in the region 104. The increase in the emission current in the subpixel circuit 302 in region 108 brightens up the region 108 more than the brightening by the emission current in subpixel circuit 302 in the region 104, thereby enabling the region 108 with lower density 110 of pixels to emit same brightness as the region 104 with higher density 106 of pixels.

[0041] As noted previously, the arrangement of low and high pixel density regions of a display panel can vary from the arrangement described above. For example, FIG. 4 A illustrates another device 400 that includes another example of a display panel 402 where a low density of the pixels is in two discrete regions 408. Each region can correspond to a front-facing sensor behind the display panel. The rest of the display (region 404) has a high density of the pixels.

[0042] In other examples, those locations can be anywhere else on the display panel. Furthermore, display panels can include more than two pixel density regions. For example, although the regions 408 are depicted as having the same pixel density, in alternate implementations those regions can have different pixel densities that are less than the high pixel density for the region 404.

[0043] The regions 408 can be toward an upper portion (e.g., toward the top) of the display panel 402. In an alternate implementation, each of the regions 408 can be located at any other location on the display panel 402. Each of the regions 408 can have the same area. The area occupied by the regions 408 collectively can be less than the area of the region 404. In some examples, the area of the regions 408 collectively can be between 5% and 10% of the area of the region 404. In certain examples, the area occupied by the regions 408 collectively can be between 2% and 20% of the area occupied by the region 404.

[0044] The status symbols — such as the symbols for data saver mode, mobile network standard (e.g., LTE, which stands for long term evolution standard for broadband communication, 5G, 4G, and/or any other standard), Wi-Fi, status (e.g., launched or testing) of mobile network, connection speed, lack of cellular data, activation of a virtual assistant, capture of a screenshot, activation of keypad, activation of teletypewriter, activation of any other feature of a phone, any other one or more symbols, amount of battery remaining, and/or any combination thereof — can be displayed in the region 404. In alternate implementations, such status symbols can be displayed in the region 408. [0045] FIG. 4B shows yet a further example of a device 500 in which a display panel 502 is divided into two regions with substantially equal areas. Specifically, a top region 508 of the display panel has a low pixel density, while a bottom region 504 has a higher pixel density.

[0046] Various implementations of the subject matter described herein (e.g., the devices 100, 400, and 500, and the corresponding display panels) can include digital electronic circuitry, integrated circuitry, specially designed application specific integrated circuits (ASICs), computer hardware, firmware, software, and/or combinations thereof. These various implementations can be implemented in one or more computer programs. These computer programs can be executable and/or interpreted on a programmable system. The programmable system can include at least one programmable processor, which can have a special purpose or a general purpose. The at least one programmable processor can be coupled to a storage system, at least one input device, and at least one output device. The at least one programmable processor can receive data and instructions from, and can transmit data and instructions to, the storage system, the at least one input device, and the at least one output device.

[0047] These computer programs (also known as programs, software, software applications or code) can include machine instructions for a programmable processor, and can be implemented in a high-level procedural and/or object-oriented programming language, and/or in assembly/machine language. As can be used herein, the term “machine-readable medium” can refer to any computer program product, apparatus and/or device (for example, magnetic discs, optical disks, memory, programmable logic devices (PLDs)) used to provide machine instructions and/or data to a programmable processor, including a machine-readable medium that can receive machine instructions as a machine-readable signal. The term “machine- readable signal” can refer to any signal used to provide machine instructions and/or data to a programmable processor.

[0048] To provide for interaction with a user, the display panel of the disclosed devices can display data to a user. The sensors of the disclosed devices can receive data from the one or more users and/or the ambient environment. Each of the devices can thus operate based on user or other feedback, which can include sensory feedback, such as visual feedback, auditory feedback, tactile feedback, and any other feedback. To provide for interaction with the user, other devices can also be provided, such as a keyboard, a mouse, a trackball, a joystick, and/or any other device. The input from the user can be received in any form, such as acoustic input, speech input, tactile input, or any other input.

[0049] Although various implementations have been described above in detail, other modifications can be possible. For example, the logic flows described herein may not require the particular sequential order described to achieve desirable results. Other implementations are within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A device comprising: an organic light emitting diode (OLED) display panel, comprising: a first region of first pixels having a first pixel density, each first pixel comprising one or more subpixels each comprising a corresponding organic light emitting diode configured to emit light of a first color and a corresponding first subpixel circuit associated with the organic light emitting diode; and a second region of second pixels having a second pixel density less than the first pixel density, each second pixel comprising one or more subpixels each comprising a corresponding organic light emitting diode configured to emit light of the first color and a corresponding second subpixel circuit associated with the organic light emitting diode; display driver integrated circuits; and signal lines electrically connecting each subpixel with the display driver integrated circuits, the signal lines comprising data lines providing a data voltage to each subpixel during operation of the device, wherein the first and second subpixel circuits and display driver integrated circuits are configured so that a brightness of the display in the first and second regions is substantially uniform when the subpixels in the first and second regions are addressed with the same data voltage.

2. The device of claim 1, wherein the first and second subpixel circuits have a common arrangement of one or more transistors and one or more capacitors, the arrangement comprising a first capacitor, wherein the first capacitor in the second subpixel circuit has a higher capacitance than the first capacitor in the first subpixel circuit.

3. The device of claim 1, wherein the first and second subpixel circuits have a common arrangement of one or more transistors and one or more capacitors, the arrangement comprising a first transistor, wherein the first transistor in the second subpixel circuit has a larger aspect ratio than the first transistor in the first subpixel circuit.

4. The device of claim 1, wherein the signal lines comprise a set of first signal lines supplying a pixel emission supply voltage to each subpixel circuit and the display driver integrated circuits are configured to apply a higher pixel emission supply voltage to the second subpixel circuits than the first subpixel circuits.

5. The device of claim 1, wherein the signal lines comprise a second set of signal lines supplying an initialization voltage to each subpixel circuit and the display driver integrated circuits are configured to apply a lower initialization voltage to the second subpixel circuits than the first subpixel circuits, the initialization voltage being a voltage that initializes a gate electrode of a first transistor of a corresponding subpixel circuit.

6. The device of claim 1, wherein each pixel comprises two or more subpixels each configured to emit light of a different color.

7. The device of claim 1, wherein the first color is red, green, or blue.

8. The device of claim 1, wherein an area of the first region is larger than an area of the second region.

9. The device of claim 1, wherein the second region is located at an edge of the display panel.

10. The device of claim 1, further comprising a sensor arranged behind the display panel and configured to sense electromagnetic radiation transmitted through the second region of the display panel.

11. The device of claim 10, wherein the sensor is a camera.

12. The device of claim 10, wherein the sensor is a facial recognition sensor.

13. The device of claim 1, wherein the OLED display is an active matrix

OLED display.

14. The device of claim 1, wherein the device is a smartphone or a tablet computer.

15. The device of claim 1, wherein each first subpixel circuit and each second subpixel circuit comprises a total of seven transistors and one capacitor.