Patent Grant
9741286
Field
The present invention relates to a display system. More particularly, embodiments of the present invention relate to interactive display panels.
Background Information
Interactive display systems are quickly becoming ubiquitous in modern electronic devices, such as cell phones, tablets, and laptop computers. A typical interactive flat panel display system includes an active matrix display panel and a separate sensor. For instance, an interactive flat panel display system typically includes an active matrix display panel and an interactive screen. The interactive screen includes a matrix of capacitors that are arranged at specific locations within the screen. The interactive screen is placed over the active matrix display panel such that the capacitors are arranged at strategic locations over the active matrix display panel. When a user interacts with the interactive screen, the capacitors output a corresponding signal to a processor. The signal is then processed as input signals and subsequently used to alter the active matrix display panel. Such interactive display systems require two separate devices to be layered together.
Other typical interactive display systems include an active matrix display panel with a separate sensor located near the active matrix display panel. These separate sensors are not layered over the active matrix display panel, but rather located adjacent to it to avoid obstructing a display region in the display panel. The sensor, such as a light sensor (e.g., a photodiode), detects intensity of light emissions and relays corresponding signals to a processor. In response, the processor calculates the received signals and controls the active matrix display panel according to the calculations. Accordingly, such interactive display systems require two separate components located adjacent one another.
Embodiments of the invention relate to methods of operating interactive display panels with light emitting diodes (LEDs) that both emit and sense light. In an embodiment, an LED is operated in a light sensing mode by selecting a sensing output data line. The sensing output data line may be coupled to a sensing circuit located on or off the display panel. In the light sensing mode, the LED is non-forward biased by the sensing circuit. The LED is coupled to both the sensing output data line and a driving circuit through a selection device. The selection device may select and deselect the sensing circuit or the driving circuit. The driving circuit operates the LED in a light emission mode to emit light. During the light sensing mode, the LED generates an output signal corresponding to an intensity of detected light that is detected by the sensing circuit. In response to the output signal, light emitted from the interactive display panel, e.g., the LED, another LED in proximity to the LED, or a number of LEDs in a subarea of the display panel area, is altered. As a result, display systems that utilize methods described herein are able to sense with emissive LEDs, as opposed to separate sensing components. The omission of separate sensing components allows for thinner, less bulky display systems.
In accordance with some embodiments, the interactive display panel described herein is a micro LED active matrix display panel formed with inorganic or organic semiconductor-based micro LEDs. For example, a micro LED active matrix display panel utilizes the performance, efficiency, and reliability of inorganic semiconductor-based LEDs for both emitting and sensing light. Furthermore, the small size of micro LEDs enables a display panel to achieve high resolutions, pixel densities, and subpixel densities. In some embodiments, the high resolutions, pixel densities, and subpixel densities are achieved due to the small size of the micro LEDs and microchips. For example, the term “micro” as used herein, particularly with regard to LEDs and microchips, refers to the descriptive size of certain devices or structures in accordance with embodiments. For example, the term “micro” may refer to the scale of 1 to 300 μm or, more specifically, 1 to 100 μm. In some embodiments, “micro” may even refer to the scale of 1 to 50 μm, 1 to 20 μm, or 1 to 10 μm. However, it is to be appreciated that embodiments of the present invention are not necessarily so limited, and that certain aspects of the embodiments may be applicable to larger, and possibly smaller size scales. For example, a 55 inch interactive television panel with 1920×1080 resolution, and 40 pixels per inch (PPI) has an approximate RBG pixel pitch of (634 μm×634 μm) and subpixel pitch of (211 μm×634 μm). In this manner, each subpixel may contain one or more micro LEDs having a maximum width of no more than 211 μm. Furthermore, where real estate is reserved for microchips in addition to micro LEDs, the size of the micro LEDs may be further reduced. For example, a 5 inch interactive display panel with 1920×1080 resolution, and 440 pixels per inch (PPI) has an approximate RBG pixel pitch of (58 μm×58 μm) and subpixel pitch of (19 μm×58 μm). In such an embodiment, not only does each subpixel contain one or more micro LEDs having a maximum width of no more than 19 μm, in order to not disturb the pixel arrangement, each microchip may additionally be reduced below the pixel pitch of 58 μm. Microchips may be arranged between pixels, subpixels, or LEDs. For example, each microchip may be characterized with a length and/or width less than the pitch between subpixels, pixels, or LEDs. In an embodiment, each microchip has a length greater than the pitch between subpixels or pixels and a width less than the pitch between subpixels or LEDs. Accordingly, some embodiments combine with efficiencies of semiconductor-based LEDs (e.g. inorganic semiconductor-based LEDs) for both emitting and sensing light with the scalability of semiconductor-based LEDs, and optionally microchips, to the micro scale for implementation into high resolution and pixel density applications.
In various embodiments, description is made with reference to figures. However, certain embodiments may be practiced without one or more of these specific details, or in combination with other known methods and configurations. In the following description, numerous specific details are set forth, such as specific configurations, dimensions and processes, etc., in order to provide a thorough understanding of embodiments of the present invention. In other instances, well-known semiconductor processes and manufacturing techniques have not been described in particular detail in order to not unnecessarily obscure embodiments of the present invention. Reference throughout this specification to “one embodiment,” “an embodiment” or the like means that a particular feature, structure, configuration, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrase “in one embodiment,” “an embodiment” or the like in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, configurations, or characteristics may be combined in any suitable manner in one or more embodiments.
In an embodiment, a display system includes a display panel with an array of LED pixels. Within each LED pixel is an array of LED subpixels. Each LED subpixel includes an LED that is coupled to a driving circuit and a sensing circuit through a sensing output data line. A selection device selects between the driving circuit and the sensing output data line to electrically couple to the LED. Accordingly, the LED is capable of being driven to emit light or sense light. In a particular embodiment, the LED is a micro LED. In some embodiments, the LED is a red, green, or blue emitting LED in a red, green, and blue (RGB) subpixel arrangement or a red, green, blue, or infrared emitting LED in a red, green, blue, and infrared (RGBIR) subpixel arrangement, although embodiments are not so limited. In an embodiment, the LED is only one color, such as a red or an infrared (IR) emitting LED that emits and senses light. Alternatively, in an embodiment, the LED is a red, green, or blue emitting LED that emits and senses light. In an embodiment, each subpixel includes a redundant pair of LEDs. Additionally, in an embodiment, each subpixel is electrically coupled with a write controller, a write driver, a sense controller, and a sense receiver. An arrangement of signals can be sent from the controllers and the drivers to each subpixel. The arrangement of signals determines what image is displayed on the display panel as well as whether the display panel is sensing light or emitting light. To sense light, an LED is operated in a light sensing mode. In an embodiment, when the LED is operated in the light sensing mode, the LED is not forward biased (“non-forward biased”). A non-forward biased LED may be driven in reverse bias with a reverse bias voltage applied by the sensing circuit, such as the sense receiver. A non-forward biased LED may be zero biased, e.g., not biased with a voltage although still operably coupled to the sensing circuit. As the LED is exposed to light during light sensing mode operation, it may generate a current or create a change in voltage or charge corresponding to an intensity of sensed light.
A write timing controller may be electrically coupled to the write controller and write driver to synchronize the data being sent to the display panel for displaying a cohesive image. In addition, a sense timing controller may be electrically coupled to the sense controller and sense receiver to synchronize reception of sensing data from the display panel for sensing with the interactive display panel. The sense receiver may receive sensing output data from each individual LED or a portion of the LEDs within the display panel.
In an embodiment, once the sense receiver receives the sensing output data from the LEDs, the sense receiver sends sense data to the sense timing controller, which then sends display panel sensing data to a processer in the form of a bitmap. The processor receives the bitmap and may use it to perform a useful operation. Using the display panel sensing data, the processor, or any other computing device, can perform a number of different operations including, but not limited to: (1) brightening or dimming a display panel in response to an amount of ambient light (ambient light detection), (2) turning the light emitting portion of a display panel on or off in response to an object's proximity to the display panel by sensing ambient light (ambient light proximity detection) or reflected light (reflected light proximity detection), (3) determine the location of an object relative to the dimensions of the display panel by sensing ambient light (ambient light object location detection) or by sensing reflected light (reflected light object location determination), (4) determining a surface profile of a target object by sensing reflected light (surface profile determination), and (5) calibrating display panel uniformity (display panel calibration). The details of each operation are discussed further below. It is to be appreciated that a processor may perform one or more of the operations in this list.
The display panel 119 may include a matrix of pixels. Each pixel may include multiple subpixels that emit different colors of lights. In a red-green-blue (RGB) subpixel arrangement, each pixel includes three subpixels that emit red, green, and blue light, respectively. In an alternative red-green-blue-infrared (RGBIR) arrangement, each pixel includes four subpixels that emit red, green, blue, and infrared light, respectively. It is to be appreciated that the RGB and RGBIR arrangements are exemplary and that embodiments are not so limited. Examples of other subpixel arrangements that can be utilized include, but are not limited to, red-green-blue-yellow (RGBY), red-green-blue-yellow-infrared (RGBYIR), red-green-blue-yellow-cyan (RGBYC), red-green-blue-yellow-cyan-infrared (RGBYCIR), red-green-blue-white (RGBW), red-green-blue-white-infrared (RGBWIR), or other subpixel matrix schemes in which the pixels have different numbers and/or colors of subpixels.
The display panel 119 may be driven by display driver integrated circuitry, which may include a write driver 111 and a write controller 113. The write controller 113 may select a row of the display panel 119 at a time by providing an ON voltage to the selected row. The selected row may be activated to receive pixel image data from the write driver 111 as will be discussed further below. In one embodiment, the write driver 111 and the write controller 113 are controlled by a write timing controller 109. The write timing controller 109 may provide the write controller 113 a write control signal 110 indicating which row is to be selected next for writing data. The write timing controller 109 may also provide the write driver 111 image data 112 in the form of a row of data voltages. Each data voltage may drive a corresponding subpixel in the selected row to emit a colored light at a specified intensity.
The display system 100 includes a receiver 107 to receive data to be displayed on the display panel 119. The receiver 107 may be configured to receive data wirelessly, by a wire connection, or by an optical interconnect. Wireless operation may be implemented in any of a number of wireless standards or protocols including, but not limited to, WiFi (IEEE 802.11 family), WiMAX (IEEE 802.16 family), IEEE 802.20, long term evolution (LTE), Ev-DO, HSPA+, HSDPA+, HSUPA+, EDGE, GSM, GPRSS, CDMA, TDMA, DECT, Bluetooth, derivatives thereof, as well as any other wireless protocols that are designated as 3G, 4G, 5G, and beyond.
The receiver 107 receives display data from an input processor 101 via an interface controller 103. In one embodiment, the input processor 101 is a graphics processing unit (GPU), a general-purpose processor having a GPU located therein, or a general-purpose processor with graphics processing capabilities. The interface controller 103 may provide display data and synchronization signals to the receiver 107, which in turn may provide the display data to the write timing controller 109. The display data may be generated in real time by the input processor 101 executing one or more instructions in a software program, retrieved from a system memory 105, or generated from local memory on the display panel 119. In an embodiment, the display panel 119 is in a “Panel Self-Refresh Mode” where the interface to the display panel is turned off and the image data is constantly generated from local memory on the display panel 119.
Depending on its applications, the display system 100 may include other components, such as a power supply, e.g., battery (not shown). In various implementations, the display system 100 may be a part of a television, tablet, phone, laptop, computer monitor, automotive heads-up display, kiosk, digital camera, handheld game console, media display, or ebook display.
According to an embodiment, in addition to being driven by the display driver integrated circuitry described above, the display panel 119 is also driven by display sensor integrated circuitry, which may include a sensing circuit (i.e., sense receiver 115) and a sense controller 117. In an embodiment, the sensing circuit is integrated into the write driver 111 such that only one data line is needed for the operation of both circuits. The sense controller 117 may select one row of the display panel 119 at a time by providing an ON voltage to the selected row. The selected row may then be operated in a light sensing mode, i.e., be non-forward biased, by the sense receiver 115 in order for the selected row to sense light. Output data from the selected row may be detected by the sense receiver 115 in the form of data voltage or current signals corresponding to the intensity of light sensed by each subpixel in the selected row. These signals may be calculated by a voltage or current calculator, such as, but not limited to, a digital to analog converter, a voltage sampler or comparator, a current sampler or comparator, and a charge amplifier located, in an embodiment, within the sense receiver 115. The sense receiver 115 may present sense data 116 to a sense timing controller 121. The sense receiver 115 and the sense controller 117 may be controlled by the sense timing controller 121. The sense timing controller 121 may provide the sense controller 117 a sense control signal 118 indicating which row is to be selected next for sensing light. The sense timing controller 121 may also present a non-forward biasing signal 114 to the sense receiver 115 to indicate a non-forward biasing voltage 228, such as no bias voltage or a reverse bias voltage, is to be applied to each subpixel in the selected row for sensing light.
In embodiments, a master timing controller 127 is connected to the write timing controller 109 and the sense timing controller 121. The master timing controller 127 may control the timing synchronization between the write timing controller 109 and the sense timing controller 121. In an embodiment, the master timing controller 127 sends and receives timing signals 128 to and from the write timing controller 109 and the sense timing controller 121. The timing signals 128 sent from the master timing controller 127 may indicate to the write and sense timing controllers when to send write and sense signals to the display panel 119. Additionally, timing signals 128 may be sent back to the master timing controller 127 to indicate when an operation has been completed. In an embodiment, the master timing controller 127 receives timing parameters from the interface controller 103. The master timing controller 127 may use the timing parameters to determine which timing scheme will be used to operate the display panel 119.
In an embodiment, the sense timing controller 121 consolidates the sense data 116 and sends the consolidated sense data 116 to an output processor 123 as display panel sensing data 125. The display panel sensing data 125 received by the output processor 123 may be in the form of one or more bitmaps where each bitmap corresponds to the consolidated sense data 116 from one color of subpixels, such as red subpixels, green subpixels, or blue subpixels in an RGB subpixel arrangement or red subpixels, green subpixels, blue subpixels, or IR subpixels in an RGBIR subpixel arrangement. The output processor 123 may then process the display panel sensing data 125 and optionally send feedback data 120 to the input processor 101 to alter the display properties of the display panel 119. The output processor 123 can be configured to perform a number of operations. For example, the output processor 123 can perform one or more of ambient light detection, ambient light proximity detection, reflected light proximity detection, ambient light object location determination, reflected light object location determination, surface profile determination, and display panel calibration as mentioned in the numbered list above. Although the output processor 123 is depicted as a separate processor, the input processor 101 and the output processor 123 can be a single processor that performs functions of both processors.
For the selected write row 201, the write timing controller 109 (shown in
In order for the selected sense row 202 to be operated in the light sensing mode to sense light, the sense timing controller 121 (shown in
Referring to
A selection device 603 is coupled to the driving circuit 601. The selection device 603 may be any conventional selection device, e.g., a multiplexer or a similar device that selects between more than one input circuit to connect to an output circuit. In an alternative example, the selection device 603 may be a transistor that turns ON to electrically connect and select a sensing output data line 511 coupled to the sensing circuit, such as sense receiver 115, to the LED 501, as will be discussed further below in
In
The selection device 603 is connected to a second source/drain electrode of the driving transistor T2, the sensing output data line 511, the sense signal line 509, and an anode electrode of the LED 501. A cathode of the LED 501 is connected to ground (Vss). In one embodiment, the selection device 603 is a multiplexer. Alternatively, the selection device 603 is another selection device that selects the sensing output data line 511 based upon an activated sense signal 224 applied through the sense signal line 509. In an embodiment, the write signal line 505 and the sense signal line 509 are activated for different subpixels in different rows within the display panel 119. For example, where the write signal line 505 is selected in row X, the sense signal line 509 may be selected in row X+1 (the row immediately below), X−1 (the row immediately above), or any other row within the display panel 119.
The driving transistor T2 may be connected to the LED 501 by a selection device 603, such as a multiplexer. The multiplexer can select between the driving transistor T2 and the sensing output data line 511 to electrically couple to the LED 501 depending upon the value of the sense signal 224 in the sense signal line 509. The transistors T1 and T2 can be any type of transistor, such as an NMOS or PMOS transistor. For example, as shown in
In an embodiment, the pixel image data line 507 and the sensing output data line 511 are merged into one pixel image data/sensing output data line 512, as shown in
In
Furthermore, in
In
The emission-selection transistor T3 is formed of a type of transistor, such as NMOS or PMOS transistor, that is the opposite of the type of transistor of which the sense-selection transistor T4 is formed. For example, in an embodiment, the emission-selection transistor T3 is formed of an NMOS transistor and the sense-selection transistor T4 is formed of a PMOS transistor, and vice versa. As such, when the sense signal 224 is activated through the sense signal line 509, either the emission-selection transistor T3 or the sense-selection transistor T4 is turned ON, but not both. Turning the emission-selection transistor T3 ON selects the driving circuit 601 so that the driving circuit 601 is electrically coupled to the LED 501, whereas turning the emission-selection transistor T3 OFF deselects the driving circuit 601 so that the driving circuit 601 is not electrically coupled to the LED 501. Additionally, turning the sense-selection transistor T4 ON selects the sensing output data line coupled to the sensing circuit, such as sense receiver 115, so that the sensing circuit is electrically coupled to the LED 501, whereas turning the sense-selection transistor T4 OFF deselects the sensing circuit so that the sensing circuit is not electrically coupled to the LED 501. In an embodiment depicted in
In
The transistors T3 and T4 may be formed of an NMOS or PMOS transistor, or any other type of transistor. In an embodiment, the emission-selection transistor T3 is formed of the same type of transistor as the sense-selection transistor T4. Alternatively, in an embodiment, emission-selection transistor T3 is formed of a different type of transistor as the sense-selection transistor T4. The emission-selection transistor T3 and the sense-selection transistor T4 are controlled by two separate control lines: the emission control line 514 and the sense signal line 509. As such, the emission-selection transistor T3 may be controlled independently from the sense-selection transistor T4 so that the sense-selection transistor T4 may be turned ON whether or not the emission-selection transistor T3 is turned ON or OFF. Turning the emission-selection transistor T3 and the sense-selection transistor T4 ON and OFF selects/deselects the driving circuit 601 and sensing circuit, respectively, according to the disclosure above in
A method of sensing light with an emissive LED in an interactive display panel 119 according to an embodiment is illustrated in
In an embodiment, the selection device 603 is a multiplexer within a subpixel of the display panel 119 as shown above in
Alternatively, in an embodiment, the selection device 603 is a selection transistor within a subpixel of the display panel 119 as shown above in
In an embodiment, the selection device 603 is a pair of opposite-type emission-selection and sense-selection transistors T3 and T4, respectively, within a subpixel of the display panel 119 as shown above in
Furthermore, in an embodiment, the selection device 603 is a pair of independently controlled emission- and sense-selection transistors T3 and T4, respectively, within a subpixel of the display panel 119 as shown above in
Referring again to
At 609, the sense receiver 115 detects the output signal from the LED within the sensing circuit. The output signal, in an embodiment, is a current flow with a magnitude corresponding to the intensity of light sensed by the first LED. Alternatively, in an embodiment, the output signal is a voltage with a magnitude corresponding to the intensity of light sensed by the first LED. The sense receiver 115 monitors the sensing output data line 511 and detects a change in current flow or a voltage amount from the LED when light is detected. For example, a greater intensity of sensed light results in a higher magnitude of current flow or voltage amount. In an embodiment, the sense receiver 115 sends the output signal to the output processor 123 through the sense timing controller 121.
At 611, the output processor 123 alters light emitted from the display panel 119 in response to the output signal received from the sense timing controller 121. In an embodiment, light emitted from the display panel 119, in whole or in part, increases or decreases. Alternatively, in an embodiment, the pattern of light emitted from the display panel 119 changes to display a different image. In embodiments, the output processor 123 is coupled to a system memory 105 carrying instructions that, when executed by the output processor, the output processor alters light emission for a number of operations. For example, the output processor 123 can alter light emission for one or more of ambient light detection, ambient light proximity detection, reflected light proximity detection, ambient light object location determination, reflected light object location determination, surface profile determination, and display panel calibration as mentioned above. Such operations are discussed in more detail below.
During operation, the LED 501 may be forward biased to emit light and non-forward biased to sense light depending upon the electrical connection made by the selection device 603.
In
In
With reference to
The frequency at which writing image data and reading sensing signals are performed may dictate the balance between sensing strength and display refresh rate. Generally, higher sensing strengths lead to more accurate sensing results whereas higher display refresh rates lead to smoother display operation.
Although the writing and reading frequencies may be the same in some embodiments, the writing and reading frequencies may be different in other embodiments. That is, the writing frequency may be higher or lower than the reading frequency.
While the display panel may write image data to and read sensing signals from all rows of the display panel in some embodiments, other embodiments may not read sense data from all rows of the display panel.
Reading and writing operations for embodiments where the pixel image data line 507 and sensing output data line 511 are integrated into a pixel image data/sensing output data line 512, as discussed above, may have different timing schemes.
A processor, such as the input processor 101 or output processor 123 from
For the read operation, at 835, the sense signal, e.g., 224 from
At 839, the sense receiver 115 non-forward biases the selected row through the sensing output data lines 511 or 512 with a non-forward biasing voltage, such as a reverse or zero bias voltage, to operate the selected row in a light sensing mode. As the selected row is exposed to light, a voltage may be generated across the LED 501 or a current may be generated through the LED 501 and into the sensing output data line 511/512. In one embodiment, the LED 501 is connected in parallel with an exposure capacitor Cx as disclosed in
In the embodiment where the LED 501 is connected in parallel with a charge capacitor Cx, at 841, the selection device 603, such as a multiplexer, disconnects the LED and the exposure capacitor Cx in the selected row. The dotted lines indicate unique operations that are performed for display panels with pixels configured with an LED 501 connected in parallel with an exposure capacitor Cx. When the LED 501 is disconnected, the LED 501 may sense light and cause the stored charge within the exposure capacitor to leak out at a rate proportionate to the amount of light sensed by the LED 501. In an embodiment, an exposure time determines the amount of time that the LED 501 and exposure capacitor Cx are disconnected. Generally, longer exposure times result in stronger, more accurate output sense signals. Once the exposure time has passed, at 843, the LED 501 and exposure capacitor Cx are reconnected to the sensing circuit.
At 845, for display panels that do not have exposure capacitors Cx, the sense receiver 115 detects the change in current or voltage from one or more LEDs within the selected row through the respective sensing output data line 511 or 512. The change in current or voltage may be the sensing output data 230, as described above, which corresponds to the intensity of light sensed by the LED 501. At 847, the sense timing controller 121 receives the sensing output data from the sense receiver 115 and builds an output data bitmap, such as display panel sensing data 125. On the other hand, for display panels that do have exposure capacitors Cx, at 845, the sense receiver 115 may detect the change in voltage from one or more exposure capacitors Cx within the selected row through the respective sensing output data line 511 or 512 and builds an output data bitmap at 847. In embodiments, the change in voltage may be the sensing output data 230, as described above, which may correspond to the intensity of light sensed by the LED 501. The sense timing controller 121 may build an output data bitmap by storing the sensing output data in its position in the bitmap.
At 849, the selection device 603 selects a driving circuit 601 based upon the sense signal 224 within the sense signal line 509. In an embodiment, the anode electrode of the LED 501 electrically couples to a driving transistor in a driving circuit, e.g., 601 in
At 851, the sense controller 117 determines whether the selected row is the last visible row in the current sense cycle. If the selected row is not the last visible row, at 853, the sense controller 117 selects the next visible row to sense light. Furthermore, the sense timing controller 121 may indicate to the master timing controller 127 that one sense operation has been completed. At 812, the master timing controller receives the indication that the sense operation has been completed and sends the next timing signal 128 to sense or write data depending on the timing scheme discussed above. If, however, the selected row is the last visible row in the display panel 119, at 855, the sense receiver 115 sends the completed output data bitmap representing the display panel sensing data 125 to the output processor 123. In an embodiment, if the selected row is the last visible row in the display panel 119, the write controller 113 can proceed to select dummy rows, if any, or to a vertical blanking phase, after which the sense receiver 115 sends the completed output data bitmap to the output processor 123.
At 857, the output processor 123 determines, based on the received display panel sensing data 125, whether or not the emission pattern or intensity of the display panel needs to be altered. Determining whether or not the emission pattern or intensity of the display panel needs to be altered can be based upon several different circumstances, as will be discussed in detail further below. If the output processor 123 determines that the display panel 119 needs to alter its emission pattern or intensity, at 861, the pixel image data 226 for one or more rows is altered. At 859, the first row of the display panel 119 is selected by the sense controller, and the method returns to the master timing controller at 812. If the output processor 123 determines that the display panel 119 does not need to alter its emission pattern or intensity, the first row is selected by the sense controller at 859, and the method returns to the master timing controller at 812.
For the write operation 863, at 814, the write signal, e.g., 222 from
At 817, the selection device 603 selects a driving circuit 601. In an embodiment, selecting the driving circuit 601 is performed simultaneously with deselecting the sensing circuit. In an embodiment, the anode electrode of the LED 501 electrically couples with a driving transistor in a driving circuit, e.g., 601 in
At 821, the write controller 113 determines whether the selected row is the last visible row in the current write cycle. If the selected row is not the last visible row, at 823, the write controller 113 selects the next row to sense light. Furthermore, the write timing controller 109 indicates to the master timing controller that one write operation has been completed. At 812, the master timing controller 127 receives the indication that the write operation has been completed and sends the next timing signal 128 to sense or write data depending on the timing scheme discussed above. If, however, the selected row is the last visible row in the display panel 119, at 825, the first row of the display panel 119 is selected by the write controller, and the method returns to the master timing controller at 812. In an embodiment, if the selected row is the last visible row in the display panel 119, the write controller 113 can proceed to select dummy rows, if any, or to a vertical blanking phase, after which the method selects the first row of the display panel at 825.
The output processor 123 may be configured to perform a number of operations by utilizing the display and sensing capabilities of the interactive display panel to alter the display based upon the display panel sensing data 125 according to embodiments. As mentioned above, the output processor 123 may be configured to perform a variety of operations, such as: (1) brighten or dim a display panel in response to an amount of ambient light (ambient light detection), (2) turn a display panel on or off in response to an object's proximity to the display panel by sensing ambient light (ambient light proximity detection) or reflected light (reflected light proximity detection), (3) determine the location of an object relative to the dimensions of the display panel by sensing ambient light (ambient light object location detection) or by sensing reflected light (reflected light object location determination), (4) determine a surface profile of a target object by sensing reflected light (surface profile determination), and (5) calibrate display panel uniformity (display panel calibration). Because such operations are not exclusive of one another, the output processor 123 may be configured to perform more than one operation.
Rather than adjusting the brightness of the entire display panel 119, the output processor 123 may adjust the brightness of a portion of the display panel 119 as depicted in
An exemplary method of performing ambient light detection with an interactive display panel 119 is illustrated in
At 911, the output processor 123 determines whether the sensing output data 230 is greater than a bright control value. In an embodiment, the bright control value corresponds to a certain brightness of light determined by an algorithm programmed by a designer. The algorithm may calculate the bright control value based upon a number of different variables established by the designer. If the sensing output data 230 is greater than the bright control value, the output processor 123 determines that the ambient light sensed is too bright for the current emission intensity of an LED, such as the first LED, and/or one or more other LEDs in proximity to the LED or in a subarea of the display panel. At 913, the output processor 123 raises an emission intensity of the LED and/or one or more other LEDs in proximity to the LED to compensate for the bright ambient light. Accordingly, the display or portions thereof will be automatically adjusted to improve visibility in situations where there is bright ambient light. Alternatively, if the sensing output data 230 is not greater than the bright control value, at 915, the output processor 123 determines whether the sensing output data 230 is less than a dim control value. In an embodiment, the dim control value corresponds to a certain dimness of light determined by an algorithm programmed by the designer. The algorithm may calculate the dim control value based upon a number of different variables established by the designer. If the sensing output data 230 is dimmer than the dim control value, the output processor 123 may determine that the ambient light sensed is too dim for the current emission intensity of the LED and/or one or more other LEDs in proximity to the LED. At 917, the output processor 123 lowers an emission intensity of the LED and/or one or more other LEDs in proximity to the LED to compensate for the dim ambient light. Accordingly, the display or portions thereof will be automatically adjusted to improve visibility in situations where there is dim ambient light.
At 919, the output processor 123 determines whether the selected LED is the last LED in the display panel (or current output data bitmap). In an embodiment, the last LED is the bottom right most LED in the display panel 119. If the LED is the last LED in the display panel, then every LED in the display panel has been processed and the first LED in the display panel is selected again at 909. Alternatively, if the selected LED is not the last LED, at 921, the output processor 123 receives an output signal from the next LED corresponding to an intensity of detected light. In an embodiment, the next LED is an LED immediately to the right of the selected LED if possible, otherwise the next LED is the left most LED in the row below the selected row.
The exemplary method in
An output processor 123 configured for ambient light proximity detection turns the light emitting function of the display panel 119 on or off in response to an object's proximity to the display panel 119 by calculating an intensity of blocked ambient light. The output processor 123 may receive a bitmap or other representation of light intensities sensed by LEDs in the display panel 119 from the sense timing controller 121. As an object 1005 moves closer to the display panel 119, more ambient light is blocked. Accordingly, the LEDs may sense less ambient light as the object moves closer to the display panel 119. After receiving the bitmap, the output processor 123 may calculate the intensity of light sensed by the LEDs and compare the intensity of light to a control value. The control value may be an intensity of sensed light that represents a threshold distance 1003 to the display panel 119. In an embodiment, the control value is determined by an algorithm programmed by a designer. The algorithm may calculate the control value based upon a number of different variables established by the designer. If the intensity of sensed light is less than the control value (indicating, for instance, that the object 1005 is blocking more than a certain intensity of light), then the output processor 123 may compare the sensed light to a threshold region of the display pane 119. The threshold region of light may represent a certain portion of the display panel 119. For example, the threshold region of light may represent half of the display panel 119. As such, if a portion of the display panel 119 that is sensing an intensity of light less than the control value is greater than the threshold region of the display panel 119 (indicating that the object 1005 is blocking more than the threshold region of the display panel 119, such as half of the display panel), then the output processor 123 may send feedback data to the input processor 101 that includes a signal to turn the light emitting function of the display panel 119 off. In an alternative example, the threshold region of light can be determined by a specific location within the display panel 119. In an embodiment, the threshold region of light represents a portion of the display panel 119 near the top of the display panel 119 closest to a speaker used for talking on a phone. If, however, the intensity of sensed light is greater than the control value (indicating that the object 1005 is blocking less than the control value of light) or the area of a region of the display panel that is sensing an intensity of light less than the control value is less than a threshold region of the display panel, then the feedback data may include a signal to keep/turn the light emitting function of the display panel 119 on. In one embodiment, the output processor 123 is configured to turn the display panel 119 off when an object, such as a person's cheek or ear, is within a distance of 2 cm from a top quarter of the display panel 119 and turn back on when the cheek or ear is farther than 2 cm from the top quarter of the display panel 119. Accordingly, the display panel 119 may advantageously save battery power by not displaying an image when more than a threshold region of the display panel 119 is blocked.
On the other hand, an output processor 123 configured for reflected light proximity detection may turn the display panel 119 off in response to an object's proximity to the display panel 119 by calculating an intensity of reflected light. The output processor 123 may receive a bitmap or other representation of light intensities sensed by LEDs in the display panel 119 from the sense timing controller 121. In an embodiment, the light sensed by the LEDs includes light emitted from a source light that is reflected off the object's surface. For example, the source light may be one or more adjacent LEDs or one or more distant LEDs from within the display panel 119. After receiving the bitmap, the output processor 123 may calculate the total intensity of reflected light sensed by the LEDs and compare the total intensity of sensed light to a control value. The control value may be a certain intensity of sensed light that represents a threshold distance 1003 to the display panel 119. In an embodiment, the control value is determined by an algorithm programmed by a designer. The algorithm may calculate the control value based upon a number of different variables established by the designer. It is to be appreciated that the intensity of reflected light generally increases as the object 1005 gets closer to the display panel 119. Accordingly, if the total intensity of sensed light is greater than the control value, then the object 1005 is too close. Additionally, the output processor 123 may compare the sensed light to a threshold region of the display panel 119. The threshold region of the display panel 119 may represent a certain portion of the display panel that is being reflected by the object, such as half of the display panel 119. If more than the threshold region of the display panel 119 is reflected, then the output processor 123 may send feedback data to the input processor 101 that includes a signal to turn the light emitting function of the display panel 119 off. In an alternative example, the threshold region of the display panel 119 can be determined by a specific location within the display panel 119. In an embodiment, the threshold region of the display panel 119 represents a portion of the display panel 119 near the top of the display panel 119 closest to a speaker or an earpiece used for talking on a phone. In this manner, the display panel 119 detects proximity to a user's face. If, however, the total intensity of sensed light is less than the control value, or the portion of the display panel that his being reflected by the object is less than the threshold region of the display panel 119, then the feedback data may include a signal to turn the light emitting function of the display panel 119 on, if off, or continue emitting light with the display panel 119.
A method of performing proximity detection to control a light emitting function of the display panel 119 is illustrated in
In the case of ambient light proximity detection, at 1015, the output processor 123 determines whether the object is within a threshold distance to the display panel 119 by comparing the lowest intensity of light sensed with a control value, such as the control value disclosed above. In embodiments, ambient light proximity detection is used when ambient light exists, such as outdoors during the day or in a brightly lit room. Accordingly, ambient light proximity detection may be useful when the display is not emitting light. The control value represents a low intensity of light to indicate that an object is within the threshold distance to the display panel 119 due to a significant amount of blocked light. In an embodiment, the lowest intensity of light sensed may be an intensity of light sensed from any LED in the display panel or any group of LEDs in the display panel. For example, the lowest intensity of light sensed may be determined by one LED or the average of the lowest 10% of light sensed by all LEDs within the display panel. As such, if the lowest intensity of light sensed crosses the control value, then the object may be determined to be within the threshold distance. In an embodiment, the group of LEDs is located near the top of the display panel 119 closest to a speaker or earpiece used for talking on a phone. If the object does not block enough light, the output processor 123 determines that the object is not within the threshold distance and the output processor 123 will continue monitoring whether or not an object comes within the threshold distance to the display panel at 1013.
In the case of reflected light proximity detection, at 1015, the output processor 123 determines whether the object is within the threshold distance to the display panel by comparing the highest intensity of light sensed with a control value. In embodiments, reflected light proximity detection is used when ambient light does not exist, such as outdoors at night or in a dark room. Accordingly, reflected light proximity detection may be useful with the display is emitting light and is the only source of light in the surrounding environment. In this case, the control value represents a high intensity of light to indicate that an object is within the threshold distance to the display panel due to a significant amount of reflected light. In an embodiment, the high intensity of light is determined by light sensed by one LED or an average of the highest 10% of light sensed by all LEDs within the display panel. In an embodiment, the intensity of light is sensed by a group of LEDs located near the top of the display panel 119 closest to a speaker or earpiece used for talking on a phone. If an object does not reflect enough light, the output processor 123 may determine that the object is not within the threshold distance and the output processor 123 will continue monitoring whether or not an object comes within the threshold distance to the display panel at 1013.
Once the object comes within the threshold distance, the output processor 123, at 1017, will then determine whether or not the object blocks or reflects more than a threshold region of the display panel 119. The threshold region of the display panel 119 can be determined by a specific location within the display panel 119. In an embodiment, the threshold region of the display panel 119 is a portion of the display panel 119 near the top of the display panel 119 closest to a speaker or earpiece used for talking on a phone. Alternatively, in an embodiment, the threshold region of the display panel 119 is represented by a percentage of blocked or reflected LEDs in the display panel 119. For example, the threshold region may be 50% of the display panel 119. Accordingly, if less than 50% of the display panel 119 is blocked or reflected, the output processor will continue monitoring whether or not an object is within the threshold distance and has blocked or reflected more than the threshold region of the display panel to the display panel 119 by looping back to 1013. Alternatively, if more than the threshold region of the display panel 119 is blocked or reflected, the output processor 123 will cause the display panel 119 to stop emitting visible light at 1019. Thereafter, at 1011, the output processor will again determine whether the display panel is emitting light. In an embodiment, the threshold region of the display panel 119 is determined by a specific location within the display panel 119. In an embodiment, the threshold region of the display panel is a portion of the display panel 119 near the top of the display panel 119 closest to a speaker or earpiece used for talking on a phone.
Continuing with the example above, when the output processor determines that the display panel is not emitting visible light, at 1021, the output processor 123 receives an output signal corresponding to an intensity of detected light. In other words, the display panel 119 continues using LEDs to sense light while not emitting visible light.
Because the display panel 119 is not emitting visible light, reflected light proximity detection may not be useful. As such, ambient light proximity detection may be used instead. In the case of ambient light proximity detection, at 1023, the output processor 123 determines whether or not the object is within the threshold distance to the display panel 119 by comparing the lowest intensity of light sensed with the control value. As established above, in an embodiment, the lowest intensity of light sensed may be determined by the average of the lowest 10% of light sensed by all LEDs within the display panel 119. As such, if the lowest intensity of light sensed crosses the control value, the output processor 123 determines that an object is within the threshold distance. Thus, the output processor 123 will continue monitoring whether the object departs from within the threshold distance to the display panel at 1021.
Once the object departs from within the threshold distance from at least a portion of the display panel 119, the output processor 123, at 1025, determines whether the object blocks more than a threshold region of the display panel 119. For example, the threshold region of the display panel 119 may be half of the display panel 119. Accordingly, if more than the threshold region of the display panel 119 is blocked, then the output processor will continue monitoring whether or not an object is within the threshold distance and has blocked more than the threshold region of the display panel 119 by looping back to 1021. Alternatively, if less than the threshold region of the display panel 119 is blocked, then the output processor 123 will cause display panel 119 to begin emitting visible light from the display panel 119 at 1027. Again thereafter, the method returns to 1011.
On the other hand, an output processor 123 configured for reflected light object location determination may determine an object's spatial location by calculating a location of reflected light. The output processor 123 may receive a bitmap 1121 (shown in
A method of performing object location determination with the display panel 119 according to an embodiment is illustrated in
At 1125, the output processor determines whether an object has moved close to the display panel. To make this determination, the output processor 123 compares an amount of sensed light with a control value. In this case, the control value may represent a complete blockage of ambient light (e.g., the darkest spot 1110 from
Once an object moves close to the display panel 119, at 1129, the output processor 123 generates a sensing bitmap representing the detected light with the object in proximity to the display panel, e.g., as illustrated in the sensing bitmap 1117 of
An exemplary method of performing surface profile determination with the interactive display panel 119 is illustrated in
Once an object moves within the threshold distance, at 1403, the output processor 123 generates a bitmap by receiving display panel sensing data 125 in the form of a bitmap corresponding to a pattern of reflected light off the object. The pattern of reflected light is created by the reflection of light off the surface profile of the object. For example, the ridges and grooves of a fingerprint will reflect light in different amounts/angles. At 1405, the output processor 123 determines the surface profile of the target object by analyzing bright and dark patterns of the bitmap.
An exemplary method of performing display panel calibration with the interactive display panel 119 is illustrated in
Alternatively, in
In an embodiment, the driving-and-selecting subpixel microchips 1601 are electrically coupled with LEDs 501 to enable the LEDs to emit and sense light. Furthermore, the driving subpixel microchips 1603 are electrically coupled with LEDs 501 to enable the LEDs 501 to emit light but not sense light. In an embodiment, alternating rows of driving-and-selecting subpixel microchips 1601 and driving subpixel microchips 1603 enables an alternating pattern of one or more rows of LEDs that emit and sense light and one or more rows of LEDs that emit light but cannot sense light. As such, depending on the desired resolution for sensing LEDs, the arrangement of driving-and-selecting microchips 1601 and driving microchips 1603 may follow accordingly.
In an embodiment, the alternating pattern of driving-and-selecting subpixel microchips 1601 and driving subpixel microchips 1603 enables a checkerboard pattern of a group of LEDs that emit and sense light and a group of LEDs that emit light but not sense light. In other embodiments, the alternating pattern can form another grid pattern of microchips 1601, 1603. As such, depending on the desired arrangement of emitting and sensing LEDs and emitting LEDs, the arrangement of driving-and-selecting subpixel microchips 1601 and driving microchips 1603 may follow accordingly.
In utilizing the various aspects of this invention, it would become apparent to one skilled in the art that combinations or variations of the above embodiments are possible for emitting and sensing light with an interactive display panel. Although the present invention has been described in language specific to structural features and/or methodological acts, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or acts described. The specific features and acts disclosed are instead to be understood as particularly graceful implementations of the claimed invention useful for illustrating the present invention.
It will be apparent from this description that aspects of the invention may be embodied, at least in part, in software. That is, the methods described with reference to
An article of manufacture may be used to store program code providing at least some of the functionality of the embodiments described above. Additionally, an article of manufacture may be used to store program code created using at least some of the functionality of the embodiments described above. An article of manufacture that stores program code may be embodied as, but is not limited to, one or more memories (e.g., one or more flash memories, random access memories—static, dynamic, or other), optical disks, CD-ROMs, DVD-ROMs, EPROMs, EEPROMs, magnetic or optical cards or other type of non-transitory machine-readable media suitable for storing electronic instructions. Additionally, embodiments may be implemented in, but not limited to, hardware or firmware utilizing an FPGA, ASIC, a processor, a computer, or a computer system including a network. Modules and components of hardware or software implementations can be divided or combined without significantly altering embodiments of the invention.
In an embodiment, a display panel includes a display substrate having a display region, and an array of light emitting diodes (LEDs) on the display substrate within the display region. The display panel also includes an array of subpixel circuits. Each subpixel circuit includes a driving circuit to operate a corresponding LED in a light emission mode and a selection device to select a sensing output data line to operate the corresponding LED in a light sensing mode. In an embodiment, each driving circuit and each selection device of the array of subpixel circuits is embedded within the display substrate. In an embodiment, the display system includes an array of driving-and-selecting microchips on the display substrate within the display region, where each driving-and-selecting microchip includes a subpixel circuit.
In an embodiment, the display panel further includes an array of driving-and-selecting microchip on the display substrate within the display region, where each driving-and-selecting microchips includes a subpixel circuit. Each driving-and-selecting microchip may be operably coupled to a plurality of LEDs within a plurality of pixels. In an embodiment, each driving-and-selecting microchip is coupled to more than one pixel within the display region. In an embodiment, each driving-and-selecting microchip has a maximum width of 1 μm to 300 μm. Each driving circuit may include a plurality of MOSFET transistors arranged to forward bias the first or second LED. The selection device may be a multiplexer, a single transistor, multiple transistors, or any other selection device capable of selecting one circuit over another.
In an embodiment, the display panel includes a second array of LEDs and an array of second subpixel circuits, each comprising a second driving circuit to operate a corresponding second LED in a light emission mode. In an embodiment, the display panel further includes a plurality of driving microchips on the display substrate within the display region, where each driving microchip contains a second subpixel circuit. In an embodiment, a first section of the display panel includes a first density of the driving-and-selecting microchips, and a second section of the display panel includes a second density of the driving-and-selecting microchips, with the second density being higher than the first density.
In an embodiment, a display system includes a sensing circuit and a display substrate having a display region. The display system may also include an array of light emitting diodes (LEDs) on the display substrate within the display region, and an array of subpixel circuits. Each subpixel circuit may include a driving circuit to operate a corresponding LED in a light emission mode and a selection device to select the sensing circuit to operate the corresponding LED in a light sensing mode.
In an embodiment, the display system further includes a processor and memory (e.g., a non-transitory machine-readable media) with instructions that, when executed, causes the processor to adjust an emission intensity of the first LED or a second LED within the display panel in response to a comparison of the detected light with a control value. The control value may be determined by an algorithm. Additionally, in an embodiment, the display system further includes a processor and memory with instructions that, when executed, causes the processor to alter a light emitting function of the display panel to stop an emission of visible light in response to comparing the detected light with a control value and determining that an object covers more than a threshold region of the display panel. The threshold region may be a portion of the display panel located at a top of the display panel. In an embodiment, the display system further includes a processor and memory with instructions that, when executed, causes the processor to determine a surface profile of a target object by detecting a pattern within the detected light, the detected light including light reflected off a surface of the target object. The light reflected off a surface of the target object may emit from a source LED located within the display panel.
Furthermore, in an embodiment, the sensing circuit generates a control bitmap representing light detected by the display panel without an object in proximity to the display panel and generates a sensing bitmap representing light detected by the display panel with the object in proximity to the display panel. The display system further includes a processor and memory with instructions that, when executed, causes the processor to compare the control bitmap with the sensing bitmap to find common variations in sensed light intensity, generate a corrected bitmap by masking out the common variations of light intensity found in both the control bitmap and the sensing bitmap, and output a set of touch coordinates based on a location in the corrected bitmap having a highest contrast. In an embodiment, the display system further includes a processor and memory with instructions that, when executed, causes the processor to adjust an amount of light emitted from a portion of the display panel in response to a comparison of the intensity of detected light sensed in the portion of the display panel with a control value.
Additionally, in an embodiment, the display system further includes a processor and memory with instructions that, when executed, causes the processor to increase a driving voltage applied to the first LED or a second LED within the display panel in response to determining that the intensity of detected light sensed by the first LED within the display panel is less than a control value. The display system may further include a master timing controller capable of synchronizing a write timing controller and a sense timing controller. The write timing controller may write image data to a storage capacitor within the display panel by operating a write controller and a write driver. In an embodiment, the sense timing controller gathers sensing output data form the display panel by operating a sense receiver and a sense controller. The sense receiver may include the sensing circuit. The write timing controller and the sense timing controller may be decoupled from one another. In an embodiment, the driving circuit and the selection device are located in a microchip. The microchip may be located on the display substrate within the display region. Additionally, in an embodiment, the sensing circuit is a sense receiver located outside of the display region. In one embodiment, the sensing circuit is integrated into a write driver located outside of the display region. The driving circuit and the selection device may be embedded within the display substrate within the display region.
In an embodiment, a method of operating a display panel includes operating a first light emitting diode (LED) in a light emission mode. Operating the first LED in a light emission mode may include forward biasing the first LED. Additionally, operating the display panel includes operating the first LED in a light sensing mode. Operating the first LED in a light sensing mode may be performed by selecting a sensing circuit in response to a sense signal and operating the first LED in a non-forward bias mode, such as a reverse or zero bias mode. An output signal corresponding to an intensity of detected light is then detected. Light emitting from the display panel is then altered in response to the output signal.
In an embodiment, the method includes emitting light with a second LED within the display panel while detecting light with the first LED. In an embodiment, detecting an intensity of light with the first LED includes detecting light emitted from the second LED of the display panel. In an embodiment, the method includes emitting light with the first LED while detecting light with a second LED within the display panel. The method may include generating a sense signal to select the sensing circuit, and generating a write signal from another driving circuit to cause the second LED to emit light, such that the sense signal and the write signal are sent at a same frequency. In an embodiment, the method includes generating the sense signal to select the sensing circuit, and generating a write signal from another driving circuit to cause the second LED to emit light, such that the sense signal is generated at a lower frequency than the write signal. The detected light may comprise light emitting from the second LED, such as a red, a green, and a blue emitting LED. In an embodiment, the detected light includes ambient light. Additionally, in an embodiment, the first LED is an emitting LED, such as a red, a green, a blue, and an infrared (IR) emitting LED. In an embodiment, the output signal is a current or voltage signal.
Altering the light emitted from the display panel in response to the output signal may include adjusting an emission intensity of the first LED and/or a second LED within the display panel in response to a comparison of the intensity of detected light with a control value. The second LED may include a group of LEDs in a subarea of the display panel. Additionally, in an embodiment, altering the light emitted from the display panel in response to the output includes altering a light emitting function of the display panel to stop an emission of visible light in response to comparing the detected light with a control value and determining that an object covers more than a threshold region of the display panel. In an embodiment, the method includes determining a surface profile of a target object by detecting a pattern within the detected light, the detected light comprising light reflected off a surface of the target object. Furthermore, in an embodiment, the method includes generating a control bitmap representing the detected light without an object in proximity to the display panel, generating a sensing bitmap representing the detected light with the object in proximity to the display panel when the object moves close to the display panel, then generating a corrected bitmap by subtracting values of intensity of detected light in the control bitmap from corresponding values in the sensing bitmap, and thereafter, outputting a set of touch coordinates based on a location in the corrected bitmap having a highest contrast.
In an embodiment, altering the light emitting from the display panel in response to the output signal includes adjusting an amount of light emitted from a portion of the display panel in response to a comparison of the intensity of detected light sensed in the portion of the display panel with a control value. Additionally, in an embodiment, altering the light emitted from the display panel in response to the output signal includes increasing a driving voltage applied to the first LED or a second LED within the display panel in response to determining that the intensity of detected light sensed by the first LED or the second LED within the display panel is less than a control value. In an embodiment, the output signal is detected from the first LED. Furthermore, in an embodiment, the output signal is detected from an exposure capacitor connected in parallel with the first LED. Moreover, in an embodiment, the sensing circuit stores charge on the exposure capacitor when operating the first LED in the reverse or zero bias mode. In an embodiment, the exposure capacitor leaks an amount of charge proportionate to an amount of light sensed by the first LED. Additionally, in an embodiment, detecting light with the first LED is performed at the same time a storage capacitor in the driving circuit for the first LED is being written with image data. Additionally, in an embodiment, the method further includes selecting the sensing circuit and deselecting the driving circuit. In an embodiment, the method further includes selecting the driving circuit and deselecting the sensing circuit. Furthermore, in an embodiment, the method further includes selecting both the driving circuit and the sensing circuit.
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