Backplane Configuration and Operation

Abstract

A backplane unit cell includes a first switch and a second switch (610, 910), a storage element (620), a comparator (810), a source (e.g., a current source or a voltage source) (630), wherein the source generates a drive signal to control the emission of a selected one of the light emitting elements (640) in a display, and wherein the drive signal is based on a power signal (975) selected by the second switch. A device includes: a backplane configured as an active matrix topology including a plurality of data columns and a plurality of row selections; and a set of electrical contacts associated with the active matrix topology and configured to electrically couple the backplane to a display having a plurality of light emitting elements configured as a passive matrix topology.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to U.S. Non-Provisional Application No. 16 / 739,740, filed on January 10, 2020, entitled “BACKPLANE CONFIGURATIONS AND OPERATIONS,” and U.S. Provisional Application No. 62 / 796,394, filed on January 24, 2019, entitled “BACKPLANE CONFIGURATIONS AND OPERATIONS,” the entire contents of which are incorporated herein by reference. Technical Field

[0003] Aspects of the present disclosure relate generally to backplanes for use with various types of displays, and more particularly to different backplane unit cells, architectures, and operations that enable high density displays, including light field displays. Background Art

[0004] An overlooked aspect of many displays is the backplane technology used to drive the pixels of the main display panel (e.g., pixel array or individual optical elements). The backplane is the design, components, or arrangement of various circuits and / or transistors responsible for turning individual pixels in the display panel on or off, and therefore plays an important role in overall display resolution, refresh rate, and power consumption.

[0005] The number of pixels in future displays is expected to increase considerably compared to current displays, which will create challenges in terms of backplane technology power consumption and overall bandwidth, which may limit the ability to realize displays with very high resolutions and pixel counts.

[0006] Therefore, techniques and devices that allow backplane technologies with low power consumption and high operating bandwidth to support high resolution displays are desirable. Summary of the invention

[0007] A simplified summary of one or more aspects is presented below to provide a basic understanding of such aspects. This summary is not a comprehensive overview of all aspects that are considered, and is not intended to identify key or important elements of all aspects, nor is it intended to delineate the scope of any or all aspects. Its purpose is to present some concepts of one or more aspects in a simplified form as a prelude to a more detailed description that is presented later.

[0008] In one aspect of the present disclosure, a backplane unit cell for driving a light-emitting element in a display is described, the backplane unit cell comprising a first switch configured to select a data signal based on a selection signal; a storage element coupled to the first switch and configured to store a value of the data signal in response to the data signal selected by the first switch; a comparator coupled to the first switch and configured to generate an output based on a comparison of the value stored in the storage element with a value of a reference signal; a second switch coupled to the comparator and configured to receive the output of the comparator to select a power signal and provide the power signal as an input to a source in response to the power signal selected by the second switch; and a source configured to generate a drive signal to control the light emission of a selected light-emitting element among the light-emitting elements in the display, the drive signal being based on the power signal, wherein the source may be a current source or a voltage source.

[0009] In another aspect of the present disclosure, a device for driving light-emitting elements in a display is described, the device comprising: a backplane configured as an active matrix topology including multiple data columns and multiple row selections; and a set of electrical contacts associated with the active matrix topology and configured to electrically couple the backplane to a display having multiple light-emitting elements configured as a passive matrix topology.

[0010] In another aspect of the present disclosure, a method of operating a backplane to drive light-emitting elements in a display is described, the method comprising the steps of sequentially selecting different rows in the backplane, and for each of a plurality of backplane unit cells associated with the different rows in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected; and, after all different rows in the backplane have been selected and the values ​​have been stored, simultaneously allowing a drive signal based on the stored value to be applied to a first row of light-emitting elements associated with each of the different rows in the backplane.

[0011] In another aspect of the present disclosure, a method of operating a backplane to drive light-emitting elements in a display is described, the method comprising: sequentially selecting different rows in the backplane, and for each of a plurality of backplane unit cells associated with different rows in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected; and for each of the different rows in the backplane, after being selected and the corresponding value is stored, sequentially allowing a drive signal based on the stored value to be applied to a first row of light-emitting elements associated with the corresponding row in the backplane. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings depict only some embodiments and are therefore not to be considered limiting in scope.

[0013] Figure 1AExamples of displays and content sources for the displays according to aspects of the present disclosure are illustrated.

[0014] Figure 1B An example of a display processing unit in a display according to aspects of the present disclosure is illustrated.

[0015] Figure 2A An example of a display having a plurality of pixels according to aspects of the present disclosure is illustrated.

[0016] Figure 2B and 2C An example of a light field display having multiple image elements according to aspects of the present disclosure is illustrated.

[0017] Figure 2D An example of a cross-sectional view of a portion of a light field display according to aspects of the present disclosure is illustrated.

[0018] Figure 3 An example of a backplane integrated with an array of light emitting elements according to aspects of the present disclosure is illustrated.

[0019] Figure 4A An example of a light emitting element array in an image element according to aspects of the present disclosure is illustrated.

[0020] Figure 4B An example of an image element having sub-image elements according to aspects of the present disclosure is illustrated.

[0021] Figure 5 An example of a backplane driver according to aspects of the present disclosure is illustrated.

[0022] Fig. 6A and 6B An example of a backplane unit cell operating using analog modulation according to aspects of the present disclosure is illustrated.

[0023] Fig. 7A and 7B An example of a backplane unit cell operating using binary coded pulse width modulation (B-PWM) according to aspects of the present disclosure is illustrated.

[0024] Fig. 8A and 8B An example of a backplane unit cell operating using single pulse width modulation (S-PWM) according to aspects of the present disclosure is illustrated.

[0025] Figures 9A-9C An example of a backplane unit cell operating using high dynamic range (HDR) pulse width modulation (HDR-PWM or H-PWM) according to aspects of the present disclosure is illustrated.

[0026] Figures 10A-10CVarious examples of backplane addressing according to aspects of the present disclosure are illustrated.

[0027] Fig.11 An example of a backplane having a hybrid matrix topology according to aspects of the present disclosure is illustrated.

[0028] Fig. 12A and 12B Different examples of driving operations of a backplane with a hybrid topology according to aspects of the present disclosure are illustrated.

[0029] Fig.13A and 13B is a flow chart illustrating different methods of driving a backplane having a hybrid topology according to aspects of the present disclosure. DETAILED DESCRIPTION

[0030] The detailed description set forth below in conjunction with the accompanying drawings is intended as an illustration of various configurations and is not intended to represent the only configuration that can be used to implement the concepts described herein. In order to provide a thorough understanding of the various concepts, the detailed description includes specific details. However, those skilled in the art will appreciate that these concepts can be implemented without these specific details. In some cases, well-known components are shown in block diagram form to avoid obscuring such concepts.

[0031] As mentioned above, the number of pixels in future displays is expected to be much larger than current displays, sometimes by several orders of magnitude. Such displays will present challenges in the type of backplane that is ultimately used, particularly from a power consumption and overall bandwidth perspective, as these factors of the backplane can limit the ability to implement displays with very high resolutions and extremely large pixel counts. Aspects to consider when deciding on an appropriate backplane include different backplane technology options as well as different backplane integration options. Among the backplane technology options to consider are semiconductor technology options, modulation options, and addressing options.

[0032] Regarding backplane technology options, various possible semiconductor technologies may be considered in conjunction with the present disclosure, including amorphous silicon (a-Si), metal oxide, low temperature polysilicon (LTPS), and complementary metal oxide semiconductor (CMOS) wafers. Of these semiconductor technologies, a-Si has the smallest maximum mobility (e.g., 1 cm 2 / V·s), bandwidth (e.g. 0.1MHz), general design rules (e.g. 3μm), and panel size (e.g. 3m). Next is metal oxide (e.g. 10cm 2 / V·s, 1MHz, 3μm, and 3m), LTPS (e.g. 100cm 2 / V·s, 10MHz, 1μm, and 2m), and CMOS wafers (e.g., 1400cm 2 / V·s, 1000MHz, 0.18μm, and 0.3m). In addition, for liquid crystal displays (LCDs), a-Si uses current drive, while for light emitting diodes (LEDs), metal oxide, LTPS, and CMOS wafers use current drive. Also, a-Si uses NMOS transistors, has a relatively low cost, limited foundry support, and is generally used in active matrix LCD (AMLCD) display applications. Similarly, metal oxide uses NMOS transistors, has a relatively low cost, limited foundry support, and is generally used in large active matrix organic LED (AMOLED) display applications. In contrast, LTPS uses CMOS, has a moderate relative cost, limited foundry support, and is generally used in mobile AMOLED display applications. Finally, CMOS wafers use CMOS, have a high relative cost, foundry support is available, and are generally used in micro displays.

[0033] Among these semiconductor technologies, LTPS and CMOS wafers can provide more flexible options for the purpose of backplane bandwidth and density requirements. For example, CMOS wafers can support bandwidths in the range of 1MHz-1,000MHz and drive unit pitches in the range of 1μm-30μm. On the other hand, LTPS can support bandwidths in the range of 1MHz-15MHz and drive unit pitches in the range of 10μm-10,000μm.

[0034] There are also various modulation options that can be used in conjunction with the backplane unit cells in the backplane. For example, one possible modulation option is analog modulation (AM), which has simple circuit complexity, low bandwidth requirements, variable current for driving LEDs, smooth grayscale gradients, and no flicker. Other possible modulations include digital modulation, such as binary coded pulse width modulation (B-PWM), which also has simple circuit complexity, high bandwidth requirements, fixed current for driving LEDs, potential contouring in grayscale gradients, and potential flicker. Another potential digital modulation option is single pulse width modulation (S-PWM), which has complex circuitry, high bandwidth requirements, fixed current for driving LEDs, smooth grayscale gradients, and potential flicker. In addition, the present disclosure proposes another possible modulation option, which is described as high dynamic range (HDR) pulse width modulation (HDR-PWM or H-PWM). This proposed modulation option has a very complex circuitry, but has lower bandwidth requirements than B-PWM or S-PWM, reduced current for driving LEDs in low light, smooth grayscale gradients, and potential flicker. This modulation in the backplane unit cell may be useful for displays that require high bandwidth and low power consumption. Additional details on these modulation options are provided below and Figures 6A-9C Combined with provision.

[0035] Furthermore, there are various backplane addressing options that are also considered. For example, passive matrix addressing uses row-by-row pixel scanning, while active matrix drives all pixels at the same time. The present disclosure proposes a hybrid of the two, where active and passive schemes are combined. Additional details on these addressing options are provided below in conjunction with Figures 10A-12B Combined with provision.

[0036] In general, the present disclosure describes various techniques and devices that allow backplanes with low power consumption and high operating bandwidth to support high-resolution displays (e.g., light field displays). These techniques and devices may take into account different features, including display applications (e.g., tablet computers, phones, watches, TVs, laptops, monitors, billboards, etc.), semiconductor technologies, modulation options, and addressing options.

[0037] Described below Figures 1A-4B A general overview is provided of the types of displays to which the various backplane aspects described in this disclosure may be applicable.

[0038] Figure 1A Diagram 100a is shown, which illustrates an example of a display 110 receiving content / data 125 (e.g., image content, video content, or both) from a source 120. Display 110 may include one or more panels (see, e.g., Figure 1B ), where each panel in the display 110 is a light emitting element panel or a reflective panel. The panel may include not only light emitting elements or light reflecting elements in a certain arrangement or array, but also a backplane for driving the light emitting elements or light reflecting elements. When light emitting element panels are used, they may include a plurality of light emitting elements (see, for example, Figure 2A The light emitting elements 220 in the embodiment of the present invention are light emitting elements 220. These light emitting elements can be light emitting diodes (LEDs) made of one or more semiconductor materials. The LEDs can be inorganic LEDs. The LEDs can be, for example, micro-LEDs, also known as microLEDs, mLEDs, or μLEDs. Other display technologies from which light emitting elements can be made include liquid crystal display (LCD) technology or organic LED (OLED) technology. The terms "light emitting element", "light emitter", or simply "emitter" can be used interchangeably in the present disclosure.

[0039] Display 110 may have capabilities including ultra-high resolution capabilities (e.g., supporting 8K and higher resolutions), high dynamic range (contrast) capabilities, or light field capabilities, or a combination of these capabilities. When display 110 has light field capabilities and can operate as a light field display, display 110 may include multiple image elements (e.g., super-raxels), wherein each image element has a corresponding light turning optical element and an array of light emitting elements (e.g., sub-raxels) monolithically integrated on the same semiconductor substrate, and wherein the light emitting elements in the array are arranged into separate groups (e.g., raxels) to provide multiple views supported by the light field display (see, e.g., Figure 2A-3 ).

[0040] Figure 1B Schematic 100b is shown in FIG. Figure 1A 110 . In this example, source 120 provides content / data 125 to a display processing unit 130 integrated within display 110. The terms "display processing unit" and "processing unit" may be used interchangeably in this disclosure. In addition to the functionality described above for a display source, source 120 may also be configured to stream red-green-blue and depth (RGBD) data from a film or special camera, and may also render RGBD data from computer-generated content. Source 120 may provide content / data 125 via, for example, HDMI / DP, and content / data 125 may be 10-bit high dynamic range (HDR) data or RGBD data.

[0041] The display processing unit 130 is configured to modify the image or video content in the content / data 125 for presentation by the display 110. A display memory 135 is also shown, which stores information used by the display processing unit 130 for processing the image or video content. The display memory 135 or a portion thereof may be integrated with the display processing unit 130. The task group that can be performed by the display processing unit 130 may include tasks associated with color management, data conversion, and / or multi-view processing operations. The display processing unit 130 may provide the processed content / data to the timer controller (TCON) 140, which in turn provides the appropriate display information to the panel 150. As described above, the panel 150 (also referred to as a display panel) may include a backplane for driving the light emitting elements or light reflecting elements in the panel 150. As illustrated in the diagram 100b, there may be multiple low voltage differential signaling (LVDS) and / or MIPI interfaces for transmitting the processed content / data from the display processing unit 130 to the TCON 140. Similarly, information or signaling from the TCON 140 to the panel 150 may be parallelized.

[0042] Figure 2A Diagram 200a in 100a shows a display 210 having a plurality of light emitting elements 220 (generally referred to as pixels or display pixels). The light emitting elements 220 are generally formed in an array and adjacent to each other to provide a higher resolution of the display 210. The display 210a may be an example of the display 110 in diagrams 100a and 100b.

[0043] exist Figure 2A In the example shown in , the light emitting elements 220 can be organized or positioned into a Q×P array, where Q is the number of rows of pixels in the array, and P is the number of columns of pixels in the array. An enlarged portion of such an array is shown to the right of the display 210. For small displays, examples of array sizes can include Q≥10 and P≥10 and Q≥100 and P≥100. For larger displays, examples of array sizes can include Q≥500 and P≥500, Q≥1,000 and P≥1,000, Q≥5,000 and P≥5,000, Q≥10,000 and P≥10,000, and larger array sizes are also possible.

[0044] Although not shown, display 210 may also include a backplane for driving the array in addition to the array of light emitting elements 220. The backplane used with display 210 may be based on the features described herein that enable a backplane with low power consumption and high bandwidth operation.

[0045] Figure 2B The diagram 200b in FIG. 1 shows a light field display 210a having a plurality of image elements or super-ray pixels 225. In the present disclosure, the term "image element" and the term "super-ray pixel" may be used interchangeably to describe similar structural units in a light field display. The light field display 210a may be an example of the display 110 in diagrams 100a and 100b having light field capabilities. The light field display 210a may be used for different types of applications, and its size may vary accordingly. For example, the light field display 210a may have different sizes when used as a display for a watch, a near-eye application, a phone, a tablet computer, a laptop computer, a monitor, a television, and a billboard (to name a few). Therefore, and depending on the application, the image elements 225 in the light field display 210a may be organized into arrays, grids, or other types of ordered arrangements having different sizes. The image elements 225 of the light field display 210a may be distributed on one or more display panels.

[0046] exist Figure 2BIn the example shown in , the image elements 225 can be organized or positioned into an N×M array, where N is the number of rows of image elements in the array and M is the number of columns of image elements in the array. An enlarged portion of such an array is shown to the right of the light field display 210a. For small displays, examples of array sizes can include N≥10 and M≥10 and N≥100 and M≥100, where each image element 225 in the array has its own array or grid of light emitting elements 220 or sub-ray pixels (as shown further to the right). For larger displays, examples of array sizes can include N≥500 and M≥500, N≥1,000 and M≥1,000, N≥5,000 and M≥5,000, and N≥10,000 and M≥10,000, where each image element 225 in the array has its own array or grid of light emitting elements 220.

[0047] When the image element or super ray pixel 225 includes different LEDs generating red (R) light, green (G) light, and blue (B) light on the same semiconductor substrate as the light emitting element 220, the light field display 210a can be said to be made of monolithically integrated RGB LED super ray pixels.

[0048] Each of the image elements 225 in the light field display 210a includes its corresponding light redirecting optical element 215 ( Figure 2C 200c in Figure 200c) can represent a minimum image element size limited by the display resolution. In this regard, the array or grid of light emitting elements 220 of image element 225 can be smaller than the corresponding light redirecting optical element 215 of this image element. However, in practice, the size of the array or grid of light emitting elements 220 of image element 225 can be similar to the size of the corresponding light redirecting optical element 215 (e.g., the diameter of the microlenses or lenslets), which in turn can be similar to or the same as the pitch 230 between image elements 225.

[0049] As described above, an enlarged version of the array of light emitting elements 220 of the image element 225 is shown on the right side of the diagram 220b. The array of light emitting elements 220 can be an X×Y array, where X is the number of rows of light emitting elements 220 in the array and Y is the number of columns of light emitting elements 220 in the array. Examples of array sizes can include X≥5 and Y≥5, X≥8 and Y≥8, X≥9 and Y≥9, X≥10 and Y≥10, X≥12 and Y≥12, X≥20 and Y≥20, and X≥25 and Y≥25. In one example, the X×Y array is a 9×9 array including 81 light emitting elements or sub-ray pixels 220.

[0050] For each image element 225, the light emitting elements 220 in the array may include separate and distinct groups of light emitting elements 220 (see, e.g. Figure 2D 260 ) in the light field display, the groups being allocated or grouped (e.g., logically grouped) based on spatial and angular proximity and configured to produce different light outputs (e.g., directional light outputs) that contribute to producing a light field view provided by the light field display 210a to a viewer. The groupings of sub-ray pixels or light elements to ray pixels need not be unique. For example, during assembly or manufacturing, there may be a mapping of sub-ray pixels to specific ray pixels that best optimizes the display experience. Once deployed, similar remapping may be performed by the display to account for, for example, aging of various parts or elements of the display, including aging of light elements of different colors and / or changes in aging of light redirecting optical elements. In the present disclosure, the term "light element group" and the term "ray pixel" may be used interchangeably to describe similar structural units in a light field display. The light field view produced by the contributions of various light element groups or ray pixels may be perceived by the viewer as a continuous or discontinuous view.

[0051] Each of the groups of light emitting elements 220 in the array of light emitting elements 220 includes a light emitting element that generates at least three different light colors (e.g., red light, green light, blue light, and possibly white light). In one example, each of the groups or ray pixels includes at least one light emitting element 220 that generates red light, one light emitting element 220 that generates green light, and one light emitting element 220 that generates blue light. Alternatively, at least one light emitting element 220 that generates white light may also be included.

[0052] exist Figure 2C 2, diagram 200c shows another example of a light field display 210a, which illustrates a magnified view of a portion of an array of image elements 225 with corresponding light redirecting optical elements 215 as described above. Pitch 230 may represent the spacing or distance between image elements 225, and may be about the size of the light redirecting optical elements 215 (e.g., the size of a microlens or lenslet). Although image elements 225 are shown as separated from one another, this is only for better illustration, and they are generally constructed to be adjacent to one another.

[0053] Figure 2D Diagram 200d in FIG. 2 shows a cross-sectional view of a portion of a light field display (eg, light field display 210a) to illustrate the present disclosure of the invention. Figure 1A1 and 2. Some of the structural units described when the display 110 in FIG. 2 is configured as a light field display. For example, diagram 200d shows three adjacent image elements or super ray pixels 225a, each with a corresponding light redirecting optical element 215. In this example, the light redirecting optical element 215 can be considered to be separate from the image element 220a, but in other cases, the light redirecting optical element 215 can be considered to be part of the image element.

[0054] like Figure 2D As shown in , each image element 225a includes a plurality of light emitting elements 220 (e.g., a plurality of sub-ray pixels), wherein several light emitting elements 220 (e.g., several sub-ray pixels) of different types may be grouped together into groups 260 (e.g., ray pixels). The groups or ray pixels may generate various components that result in a particular ray element 255, as shown by the rightmost group or ray pixel in the middle image element 225a. It is to be appreciated that the ray elements 255 generated by different groups or ray pixels in different image elements may result in a view perceived by a viewer that is far from the light field display.

[0055] Figure 2D An additional structural unit described in is the concept of a sub-picture element 270, which represents a grouping of light emitting elements 220 of the same type (eg generating the same light color) of picture element 225a.

[0056] As in the other examples above, Figure 2D Some of the components shown in diagram 200d in FIG. 2 as being separated from each other are shown as such only for better illustration, and they can generally be built adjacent to each other.

[0057] Figure 3 The diagram 300 in FIG. 1 illustrates an example of a backplane integrated with an array of light emitting elements. Figure 2D 200d in FIG. 200a. Diagram 300 shows light emitting element optics (sub-ray pixels) 220, light emitting element groups (ray pixels) 260, image elements (super-ray pixels) 225a, and light redirection optics 215. Also shown is how various rays 255 from different image elements can contribute to the generation of representations of different views (e.g., view A and view B). Also shown are the light emitting elements 220 of image element 225a forming a larger array 330, which is then connected to a backplane 310, which in turn is configured to drive each of the light emitting elements 220.

[0058] Figure 4ADiagram 400a is shown that depicts various details of one embodiment of an image element 225. For example, the image element 225 (e.g., super-ray pixel) has a corresponding light-diverting optical element 215 (shown in dashed lines) and includes an array or grid 410 of light-emitting elements 220 (e.g., sub-ray pixels) monolithically integrated on the same semiconductor substrate. The light-diverting optical element 215 can have the same or similar dimensions as the array 410, or can be slightly larger than the array 410 as shown. It is to be understood that some of the dimensions illustrated in the drawings of the present disclosure have been exaggerated for purposes of illustration and need not be considered an accurate representation of actual or relative sizes.

[0059] The light emitting elements 220 in the array 410 include different types of light emitting elements to produce light of different colors, and are arranged into separate groups 260 (eg, separate ray pixels) that provide different contributions to the multiple views produced by the light field display.

[0060] like Figure 4A As shown in FIG. 4 , array 410 has a geometric arrangement to allow two or more image elements to be placed adjacently or closely together. The geometric arrangement may be a hexagonal shape (e.g., Figure 4A ), a square shape, or a rectangular shape.

[0061] Although not shown, Figure 4A The picture element 225 in the image element 225 may also have corresponding electronic components (for example in a backplane), which include a plurality of driving circuits configured to drive the light emitting elements 220 in the picture element 225.

[0062] Figure 4B Diagram 400b is shown, which describes various details of another embodiment of image element 225. For example, Figure 4B The image element 225 (e.g., super-ray pixel) in the embodiment includes multiple sub-image elements 270 monolithically integrated on the same semiconductor substrate. Each sub-image element 270 has a corresponding light-diverting optical element 215 (shown in dashed lines) and includes an array or grid 410a of light-emitting elements 220 (e.g., sub-ray pixels) that produce the same light color. The light-diverting optical element 215 can have the same or similar size as the array 410a, or can be slightly larger than the array 410a as shown. For the image element 225, the light-diverting optical element 215 of one of the sub-image elements 270 is configured to optimize the dispersion for the light color produced by the light-emitting element 220 in the sub-image element 270. And, the light-diverting optical element 215 can be aligned and engaged with the array 410a of the corresponding sub-image element 270.

[0063] The light emitting elements 220 of the sub-image element 270 are arranged into separate groups 260 (eg, ray pixels). Figure 4B As illustrated, in one example, each group 260 may include collocated light emitting elements 220 from each of the sub-image elements 270 (e.g., the same position in each sub-image element). However, as described above, the mapping of various light emitting elements 220 to different groups 260 may vary during manufacturing and / or operation.

[0064] like Figure 4B As shown in FIG. 4 , array 410 a has a geometric arrangement to allow two or more sub-image elements to be placed adjacently. The geometric arrangement may be a hexagonal shape (e.g. Figure 4B ), a square shape, or a rectangular shape.

[0065] Although not shown, Figure 4B The picture elements 225 in the sub-picture elements 270 may also have corresponding electronic components (e.g., in a backplane) including a plurality of drive circuits configured to drive the light emitting elements 220 in the picture elements 225. In some examples, one or more common drive circuits may be used for each of the sub-picture elements 270.

[0066] Figure 5 500 in the figure illustrates an example of a simplified schematic diagram of a backplane driver (e.g., display driver 510) that can be used in a display to drive a backplane. Display driver 510 can be configured to generate signals that provide appropriate information to the backplane and pixel array in a display panel (e.g., panel 150) to operate together to reproduce image and / or video content.

[0067] The display driver 510 can generate row select signals ("Row Select"), which are provided to the row driver 520 to control the selection of rows in the pixel array 540. The display driver can also generate column data ("Column Data"), which is provided to the column driver 530, which in turn controls how the data is provided to the pixel array 540 to be reproduced. In some embodiments, the row driver 520 and the column driver 530 are considered to be part of the backplane architecture, while in other embodiments, they can be considered to be separate from the backplane architecture. The pixel array 540 can include not only the optical elements associated with each pixel, but also the corresponding backplane transistors and / or circuitry.

[0068] Fig. 6A and 6BDiagrams 600a and 600b are shown, which illustrate examples of backplane unit cells that operate using analog modulation (AM). This backplane unit cell configuration is shown in diagram 600a and includes a first switch 610, a storage element 620, and a source 630. A light-emitting element 640 electrically connected to the source 630 is also shown, but the light-emitting element 640 does not form part of the backplane architecture like the backplane unit cell. In one embodiment, the first switch 610 and the storage element 620 (also referred to as a 2T1C circuit) can be made with two transistors (2T) and a capacitor (C), respectively. Although the source 630 is shown as a current source, it can also be a current source or a voltage source depending on the light-emitting element 640 used. For example, when the light-emitting element 640 is a pixel in a liquid crystal display (LCD), the source 630 can be a voltage source. Alternatively, when the light-emitting element 640 is an LED, the source 630 can be a current source.

[0069] In this backplane unit cell configuration, a row select signal ("Row") selects a column data value ("Column"), and the selected value is stored in storage element 620. Figure 5 In the diagram 500 in FIG. 5 , the row select signal may correspond to “row select” and / or the output of the row driver 520, and the column data may correspond to “column data” and / or the output of the column driver 530. The value stored in the storage element 620 is then provided to the source 630 to drive the light emitting element 640. The intensity of the light generated by the light emitting element 640 may be based on the drive signal provided by the source 630, which in turn may be based on the value stored in the storage element 620.

[0070] The operation of the backplane unit cell in diagram 600a, generally described above, is described in more detail in timing diagram 600b. Signal 670 represents a video frame, while signal 671 represents a row selection of column data to be stored in storage element 620. Signal 672 corresponds to the column data (which may vary over time), while signal 673 (dashed line) is a value corresponding to the column data value that is stored in storage element 620 upon row selection and remains unchanged until the next row selection is made.

[0071] For this configuration of the backplane unit cell, when the light emitting element 640 is an LED, its bandwidth is proportional to the refresh frequency f used. refresh Correspondingly, the row and column bandwidths are similar to f refresh · rows, where rows is the number of rows. The AM backplane unit cell thus provides a simple circuit with low bandwidth requirements and a variable current for the LEDs as light emitting elements 640.

[0072] Fig. 7A and 7BDiagrams 700a and 700b are shown, which illustrate examples of backplane unit cells operating using binary coded pulse width modulation (B-PWM). This backplane unit cell configuration is shown in diagram 700a and includes a first switch 610, a storage element 620, and a source 630, which is similar to the above with Fig. 6A and 6B 600a and 600b in conjunction with the backplane unit cell configuration described in connection with the same configuration. A light emitting element 640 is also shown electrically connected to a source 630. However, in this example, the row select signal ("row") that selects the column data value ("column") stored in the storage element 620 is a digital signal that causes a binary coded pulse width modulation of the value stored in the storage element 620 and provided to the source 630 to drive the light emitting element 640.

[0073] The operation of the backplane unit cell in diagram 700a, generally described above, is described in more detail in timing diagram 700b. Signal 770 represents a video frame, while signal 771 represents a row selection of column data to be stored in storage element 620, where signal 771 is a binary coded signal to produce a binary coded pulse width modulation. In this example, the binary coded signal is a binary code of 1001. Signal 772 corresponds to the column data (which may change over time), while signal 773 (dashed line) is the value stored in storage element 620 at the time of row selection and remains unchanged until the next row selection is made.

[0074] For this configuration of the backplane unit cell, when the light emitting element 640 is an LED, its bandwidth and the bandwidth of the rows and columns are similar to f refresh ·rows·2 n Corresponding to, where n is the number of bits in the binary code. The B-PWM backplane unit cell thus provides a simple circuit with high bandwidth requirements and a fixed current for the LED as the light emitting element 640.

[0075] Fig. 8A and 8B Diagrams 800a and 800b are shown, which illustrate examples of backplane unit cells operating using single pulse width modulation (S-PWM). This backplane unit cell configuration is shown in diagram 800a and includes a first switch 610, a storage element 620, a source 630, and a comparator 810. A light emitting element 640 electrically connected to the source 630 is also shown.

[0076] In this backplane unit cell configuration, a row select signal ("Row") selects a column data value ("Column"), and the selected value is stored in storage element 620. The value stored in storage element 620 is then provided to comparator 810 for comparison with a reference signal ("Reference"), and the output of comparator 810 is then provided to source 630 to drive light emitting element 640. The reference signal, also known as a reference ramp, is a non-linear signal that can be used to incorporate gamma correction into this backplane unit cell configuration.

[0077] The operation of the backplane unit cell in diagram 800a, generally described above, is described in more detail in timing diagram 800b. Signal 870 represents a video frame, while signal 871 represents a row selection of column data to be stored in storage element 620. Signal 872 corresponds to the column data (which may vary over time), while signal 873 (short dashed line) is the value stored in storage element 620 upon row selection and remains unchanged until the next row selection is made.

[0078] Signal 874 corresponds to a reference signal ("reference") provided to comparator 810, while signal 875 (long dashed line) corresponds to the output of comparator 810. Signal 874 goes low and then returns again after signal 872 has finished providing all column data for the current video frame. In some embodiments, signal 874 can be low and then rise after signal 872 has finished providing all column data for the current video frame. Comparator 810 compares signals 873 and 874 such that when the value of signal 873 (column data value) is greater than the value of signal 874 (reference signal value), signal 875 is high and source 630 drives light emitting element 640. On the other hand, when the value of signal 873 is less than the value of signal 874, signal 875 is low and source 630 does not drive light emitting element 640.

[0079] For this configuration of the backplane unit cell, when the light emitting element 640 is an LED, its bandwidth is similar to f refresh 2 n corresponding to, and the row and column bandwidths are similar to f refresh The S-PWM backplane unit cell therefore requires a more complex circuit with high bandwidth requirements, fixed current for the LED as the light emitting element 640, and smooth grayscale (eg, gamma correction provided by the reference signal).

[0080] Figures 9A-9CDiagrams 900a, 900b, and 900c are shown, which illustrate examples of backplane unit cells operating using high dynamic range (HDR) pulse width modulation (H-PWM). This backplane unit cell configuration is shown in diagram 900a and includes a first switch 610, a storage element 620, a source 630, a comparator 810, and a second switch 910. A light emitting element 640 is also shown.

[0081] In this backplane unit cell configuration, a row select signal ("row") selects a column data value ("column"), and the selected value is stored in the storage element 620. The value stored in the storage element 620 is then provided to the comparator 810 for comparison with the reference signal ("reference"), and the output of the comparator 810 is then provided to the second switch 910. The second switch 910 can be used to select the power signal ("power") provided to the source 630 to drive the light emitting element 640. The reference signal (also called a reference ramp) is a nonlinear signal that can be used to incorporate gamma correction into this backplane unit cell configuration. The power signal (also called a power ramp) is a nonlinear signal that can be used to enable a high dynamic range at the same bandwidth. The reference signal can be a sublinear signal, and the power signal can be a superlinear signal.

[0082] The operation of the backplane unit cell in diagram 900a, generally described above, is described in more detail in timing diagram 900b. Signal 970 represents a video frame, while signal 971 represents a row selection of column data to be stored in storage element 620. Signal 972 corresponds to the column data (which may vary over time), while signal 973 (short dashed line) is the value stored in storage element 620 at the time of row selection and remains unchanged until the next row selection is made.

[0083] Signal 974 corresponds to a reference signal ("reference") provided to comparator 810, signal 975 (dashed dot line) corresponds to a power signal ("power"), and signal 976 (long dashed line) corresponds to the output of comparator 810. Comparator 810 compares signal 973 to signal 974, such that when the value of signal 973 (column data value) is greater than the value of signal 974 (reference signal value), the output of comparator 810 is high and the power signal (signal 975) is selected as the input of source 630 for driving light emitting element 640. As illustrated, when the output of the comparator is high, signal 976 follows signal 975. On the other hand, when the value of signal 973 is less than the value of signal 974, the output of comparator 810 is low and source 630 does not drive light emitting element 640. As illustrated, when the output of comparator 810 is low, so is signal 976.

[0084] Diagram 900c shows Fig. 9B973, 974, 975, and 976 in diagram 900b in more clearly illustrates the operation. When signal 973 (e.g., the stored value in storage element 620) is less than signal 974 (e.g., the reference signal), the output of comparator 810 is high, and signal 976 for source 630 to drive light emitting element 640 follows signal 975 (e.g., the power signal), which is selected using second switch 910. When signal 974 is greater than signal 973, the output of comparator 810 is low and so is signal 976, which no longer follows signal 975.

[0085] For this configuration of the backplane unit cell, when the light emitting element 640 is an LED, its bandwidth is similar to f refresh 2 n Correspondingly, the row and column bandwidths are similar to f refresh The H-PWM backplane unit cell therefore requires a more complex circuit with lower bandwidth requirements, reduced current at low intensity for the LEDs as the light emitting elements 640. Also, gamma correction and high dynamic range can be achieved using this configuration.

[0086] The above Figures 6A-9C Different modulation options that can be used in conjunction with the backplane unit cells in the backplane are shown. As described, one possible modulation option is analog modulation (AM), which has simple circuit complexity, low bandwidth requirements, variable current for driving the LEDs, smooth grayscale gradients, and no flicker (see, e.g. Fig. 6A and 6B ). Another possible modulation includes digital modulation, such as B-PWM, which also has simple circuit complexity, high bandwidth requirements, fixed current for driving LEDs, potential contours in grayscale gradients, and potential flicker (see e.g. Fig. 7A and 7B Yet another possible digital modulation option is S-PWM, which has complex circuitry, high bandwidth requirements, fixed current for driving the LEDs, smooth grayscale gradients, and potential flicker (see e.g. Fig. 8A and 8B ). In addition, the present disclosure proposes yet another possible modulation option, which is described as HDR-PWM or H-PWM. This newly proposed modulation option has the most complex circuit system, lower bandwidth requirements than B-PWM or S-PWM, reduced current for driving LEDs in low light, smooth grayscale gradients, and potential flicker, making it suitable for displays that require high bandwidth and low power consumption.

[0087] Figures 10A-10CThe diagrams 1000a, 1000b, and 1000c in Figure 1 illustrate various examples of backplane addressing. In diagram 1000a, a passive matrix configuration using row-by-row pixel scanning is shown. In this example, a pixel may refer to a sub-ray pixel as described above or an individual light emitting element. The passive matrix configuration is shown with dotted lines to indicate that it will be fully implemented on the pixel array of the display panel and will not be implemented on the backplane of the display panel. This example shows multiple row selections 1010a and 1010b, multiple columns 1020a and 1020b, and multiple light emitting elements 1030 (e.g., LEDs) at the intersection of each row selection and column.

[0088] For a passive matrix configuration, when LEDs are used for the light emitting element 1030, each LED has no driver unit or contacts, the contact geometry is rows and columns, flicker may exist on large displays, the peak current of the LED may be high, and there is no backplane matrix density. Also, the maximum LED duty cycle is 1 / (Row view ·Rpw pixel ).

[0089] In diagram 1000b, an active matrix configuration is shown where all pixels (e.g., sub-ray pixels) are driven at all times. An active matrix configuration is shown where the light emitting elements 1030 are dashed to indicate that they would be implemented entirely on the pixel array of the display panel, and solid lines are used to indicate those components that would be implemented on the backplane of the display panel. This example shows a plurality of row selects 1040a and 1040b, a plurality of columns 1050a and 1050b, and a plurality of light emitting elements 1030 (e.g., LEDs). Also, each light emitting element 1030 uses one backplane unit cell. In this example, the same backplane unit cells as described above are used. Fig. 6A and 6B A simple AM ​​backplane unit cell configuration similar to the configuration described in conjunction with the description and having a 2T1C circuit. In this case, transistor 1060 corresponds to first switch 610, capacitor 1064 corresponds to storage element 620, and transistor 1062 corresponds to source 630. Other backplane unit cells (such as the backplane unit cells described above) may also be used.

[0090] For active matrix configuration, when LEDs are used for light emitting element 1030, each LED has one driver unit or contact, the contact geometry is point and ground, there is no flicker, the peak LED current is low, and it has the highest backplane matrix density. And, the maximum LED duty cycle is 1.

[0091] Finally, in diagram 1000c, a proposed hybrid matrix configuration is shown. This configuration can be used with any type of display. When considering a light field display, the image elements or super ray pixels can use an active matrix approach, while the light emitting elements or sub ray pixels within those image elements can use a passive matrix approach. A hybrid matrix configuration is shown, where the light emitting elements 1030, columns 1020a and 1020b, and row selects 1010a and 1010b are dashed lines to indicate that they will be fully implemented on the pixel array of the display panel, while solid lines are used to indicate those components that will be implemented on the backplane of the display panel, including row selects 1040a and columns 1050a and 1050b. Each column of light emitting elements 1030 (e.g., LEDs) uses a backplane unit cell, which in this example consists of a simple AM ​​backplane unit cell with a transistor 1060, a capacitor, and a transistor 1062. Other backplane unit cells (e.g., the backplane unit cells described above) can also be used.

[0092] For a hybrid matrix configuration, when LEDs are used in the light emitting element 1030, each LED has 1 / Row view The driver unit or contact, the contact geometry is rows and columns, there may be slight flicker, the peak current of the LED may be medium, and the backplane matrix density is also medium. And the maximum LED duty cycle is 1 / Row view .

[0093] Fig.11 A diagram 1100 is shown having an example of a backplane with a hybrid matrix topology that follows Fig. 10C 1000c. Similar to diagram 1000c, dashed lines indicate those components or parts that will be fully implemented on the pixel array of the display panel, while solid lines are used to indicate those components that will be implemented on the backplane of the display panel. In this example, multiple columns 1110 for addressing light emitting elements 1130 (e.g., LEDs) are shown. Active matrix operations implemented in the backplane in the hybrid matrix topology involve AM row selections 1120, such as AM1 and AM2. Passive matrix operations implemented in the array of light emitting elements 1130 in the hybrid matrix topology involve PM row selections 1140, such as PM1.1, PM1.2, PM1.3, and PM1.4 associated with AM1, and PM2.1, PM2.2, PM2.3, and PM2.4 associated with AM2. The number of columns 1110, AM row selections 1120, and PM row selections 1140 is provided by way of illustration and not limitation.

[0094] Also shown in diagram 1100 is a backplane unit cell 1150, which may be any of the backplane unit cells described above. For illustration purposes and to keep the hybrid matrix topology easy to read, a simple 2T1C backplane unit cell is shown.

[0095] Light emitting element group 1160 corresponding to one of column 1110 groups and AM row selection 1120 and its corresponding PM row selection 1140 may correspond to a light emitting element of an image element (super-ray pixel), in which case group 1160 is considered to correspond to the image element. Similarly, group 1150 may correspond to less than one image element (e.g., half or one quarter of the light emitting elements of the image element) or to more than one image element (e.g., one and one quarter, one and one half, twice the image element).

[0096] In the example of diagram 1100, each of the data columns and each of the row selections may be directly accessible via one or more edges of the backplane.

[0097] Fig. 12A and 12B Diagrams 1200a and 1200b are shown, which illustrate a hybrid topology (eg Fig.11 Different examples of driving operations for a backplane of a hybrid topology (described in diagram 1100 in FIG. 1 ).

[0098] Diagram 1200a is a timing diagram illustrating an example of when active matrix and passive matrix operation of a backplane hybrid topology can be performed. In this case, AM row selections (e.g., AM1, AM2, AM3) are offset from each other by one time unit, while PM row selections (e.g., PM1.1, PM2.1, PM3.1) occur at the same time. For example, AM1 is selected at time units 1, 5, 9, and 13 (cross-hatched), AM2 is selected at time units 2, 6, 10, and 14 (cross-hatched), and AM3 is selected at time units 3, 7, 11, and 15 (cross-hatched).

[0099] After selecting AM1, AM2, and AM3 at time units 1, 2, and 3, respectively, PM1.1, PM2.1, and PM3.1 are selected at time unit 4 (diagonal). After selecting AM1, AM2, and AM3 at time units 5, 6, and 7, respectively, PM1.2, PM2.2, and PM3.2 are selected at time unit 8 (diagonal). After selecting AM1, AM2, and AM3 at time units 9, 10, and 11, respectively, PM1.3, PM2.3, and PM3.3 are selected at time unit 12 (diagonal). Finally, after selecting AM1, AM2, and AM3 at time units 13, 14, and 15, respectively, PM1.4, PM2.4, and PM3.4 are selected at time unit 16 (diagonal). When there are more than three (3) AM row selections and more than four (4) PM row selections per AM row selection, a method similar to that outlined in this timing diagram may be followed.

[0100] Diagram 1200b is a timing diagram illustrating another example of when active matrix and passive matrix operation of a backplane hybrid topology can be performed. In this case, the AM row selections (e.g., AM1, AM2, AM3) are offset from each other by one time unit, as are the PM row selections (e.g., PM1.1, PM2.1, PM3.1). For example, AM1 is selected at time units 1, 4, 7, 10, and 13 (cross-hatched), AM2 is selected at time units 2, 5, 8, 11, and 14 (cross-hatched), and AM3 is selected at time units 3, 6, 9, and 12 (cross-hatched).

[0101] After selecting AM1, AM2, and AM3 at time units 1, 2, and 3, respectively, PM1.1 is selected at time units 2 and 3 (diagonal), PM2.1 is selected at time units 3 and 4 (diagonal), and PM3.1 is selected at time units 4 and 5 (diagonal). The other selections for AM1, AM2, and AM3 are similar. In this method, PM row selection does not need to wait until all AM row selections occur. When there are more than three (3) AM row selections and more than four (4) PM row selections for each AM row selection, a method similar to the method outlined in this timing diagram can be followed.

[0102] Fig.13A and 13B are flow charts illustrating methods 1300a and 1300b, respectively, of driving a backplane having a hybrid topology using the driving operations described above in conjunction with timing diagrams 1200a and 1200b.

[0103] Method 1300a is a method of operating a backplane to drive light emitting elements in a display, wherein the backplane has a hybrid topology configuration. Method 1300a is based at least in part on Fig. 12A 1200a in the timing diagram.

[0104] At 1310, method 1300a includes the steps of sequentially selecting different rows in the backplane (e.g., AM1, AM2, and AM3), and for each of a plurality of backplane unit cells associated with the different rows in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected.

[0105] At 1315, method 1300a includes the steps of: after all different rows in the backplane have been selected and the values ​​have been stored, simultaneously allowing drive signals based on the stored values ​​to be applied to the first row of light-emitting elements associated with each of the different rows in the backplane (e.g., rows selected with PM1.1, PM2.1, and PM3.1).

[0106] In one aspect, the method 1300a may include the following steps: at 1320, for each of the different rows in the backplane, simultaneously disabling the application of a drive signal to a first row of light emitting elements. The method 1300a may also include the following steps: at 1325, sequentially selecting the different rows in the backplane again, and for each of the plurality of backplane unit cells associated with the different rows in the backplane, storing the value provided in the corresponding data column when the corresponding row in the backplane is selected again. The method 1300a may further include the following steps: at 1330, after all the different rows in the backplane have been selected again and the values ​​are stored, simultaneously enabling the application of a drive signal based on the stored value to a second row of light emitting elements associated with each of the different rows in the backplane. The first row of light emitting elements and the second row of light emitting elements may be part of a subset of rows of light emitting elements in a display. The first row of light emitting elements and the second row of light emitting elements in the subset are respectively different from the light emitting elements of the first physical row and the light emitting elements of the second physical row in the display.

[0107] Method 1300a may further include, for each of the remaining rows of light emitting elements following the first row of light emitting elements in the set of light emitting element rows associated with each row in the different rows in the backplane, performing the following: simultaneously prohibiting application of a drive signal to a previous row of light emitting elements; sequentially selecting a different row in the backplane again, and for each of a plurality of backplane unit cells associated with a different row in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected again; and after all different rows in the backplane have been selected again and the values ​​have been stored, simultaneously allowing application of a drive signal based on the stored value to a current row of light emitting elements associated with each row in the different rows in the backplane.

[0108] In another aspect, the drive signal is allowed to be applied for a period of time that is longer than the period of time that each row in the backplane is selected.

[0109] Method 1300b is another method of operating a backplane to drive light emitting elements in a display, wherein the backplane has a hybrid topology configuration. Method 1300b is based at least in part on Fig. 12B See timing diagram 1200b in FIG.

[0110] At 1350, method 1300b includes the steps of sequentially selecting different rows in the backplane (e.g., AM1, AM2, and AM3), and for each of a plurality of backplane unit cells associated with the different rows in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected.

[0111] At 1355, method 1300b includes the following steps: for each of the different rows in the backplane, after being selected and the corresponding value is stored, sequentially allowing a drive signal based on the stored value to be applied to a first row of light-emitting elements associated with the corresponding row in the backplane (e.g., a row selected with PM1.1, PM2.1, and PM3.1).

[0112] In one aspect, method 1300b includes the following steps: At 1360, the drive signal remains enabled to be applied to the first row of light emitting elements until the corresponding row in the backplane is selected again.

[0113] In another aspect, the method 1300b may include, at 1365, sequentially disabling application of a drive signal to a first row of light emitting elements for different rows in the backplane. The method 1300b may also include, at 1370, sequentially selecting different rows in the backplane again, and for each of a plurality of backplane unit cells associated with different rows in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected again. The method 1300b may further include, at 1375, for each of the different rows in the backplane, after being selected and the corresponding value being stored, enabling application of a drive signal based on the stored value to a second row of light emitting elements associated with the corresponding row in the backplane. And, the method 1300b may also include, at 1380, maintaining enabling application of a drive signal to a second row of light emitting elements until the corresponding row in the backplane is selected again. The first row of light emitting elements and the second row of light emitting elements may be part of a subset of rows of light emitting elements in a display. The first row of light emitting elements and the second row of light emitting elements in the subset are respectively different from the light emitting elements of the first physical row and the light emitting elements of the second physical row in the display.

[0114] Method 1300b may further include: for each of the remaining rows of light-emitting elements after the first row of light-emitting elements in the set of light-emitting element rows associated with each row in the different rows in the backplane, performing the following: for the different rows in the backplane, sequentially prohibiting the application of a drive signal to a previous row of light-emitting elements; sequentially selecting the different rows in the backplane again, and for each of the multiple backplane unit cells associated with the different rows in the backplane, storing a value provided in a corresponding data column when the corresponding row in the backplane is selected again; and for each of the different rows in the backplane, after being selected again and the corresponding value is stored, allowing the drive signal based on the stored value to be applied to the current row of light-emitting elements associated with the corresponding row in the backplane.

[0115] This disclosure describes various techniques and devices that enable backplanes that may have low power consumption and high operating bandwidth for use with high-resolution displays, such as light field displays.

[0116] Therefore, although the present disclosure has been provided according to the illustrated embodiments, those skilled in the art will readily recognize that there may be variations of the embodiments, and those variations will fall within the scope of the present disclosure. Therefore, those skilled in the art may make many modifications without departing from the scope of the appended claims.

Claims

1. A device comprising a backplane, the backplane comprising a plurality of backplane unit cells for driving light-emitting elements in a display, each backplane unit cell comprising: a first switch configured to select a data signal based on a selection signal; a storage element coupled to the first switch and configured to store a value of a selected data signal in response to the data signal selected by the first switch; a comparator coupled to the first switch and configured to generate an output based on a comparison of the value stored in the storage element and a value of a reference signal; a second switch coupled to the comparator and configured to receive the output of the comparator to select a power signal, and to provide the power signal as an input of a source in response to the power signal selected by the second switch; as well as The source is configured to generate a driving signal to control the light emission of a selected light emitting element among the light emitting elements in the display, the driving signal is based on the power signal, and the source is a current source or a voltage source; The reference signal and the power signal are both nonlinear signals. 2 . The apparatus of claim 1 , wherein the reference signal is a global reference signal provided to more than one backplane unit cell in the backplane. 3 . The apparatus of claim 1 , wherein the power signal is a global power signal provided to more than one backplane unit cell in the backplane.

4. The apparatus according to claim 1, wherein: The reference signal is a sublinear signal, and The power signal is a super linear signal.

5. The device of claim 1, wherein the storage element comprises at least one capacitor. 6 . The apparatus of claim 1 , wherein the storage element is configured to store the value of the data signal until a next value is stored in response to a next selection signal selecting a next data signal at the first switch.

7. The apparatus of claim 1, wherein: The data signal is a backplane column select signal, and The selection signal is a backplane row selection signal.

8. The apparatus of claim 1, wherein: The light emitting element is a light emitting diode LED, and The source is configured to drive the LED.

9. The device of claim 8, wherein the LED is an inorganic LED.

10. A method of operating a device according to any one of claims 1 to 9 to drive a light emitting element in a display, comprising: within the backplane unit cell, storing a value of a data signal on a storage element in response to a select signal; comparing, by the backplane unit cell, the value stored in the storage element with a value of a reference signal to generate an output of the comparison; selecting a power signal via said backplane unit cell and said output based on said comparison; as well as A drive signal for a selected one of the light emitting elements in the display is generated by the backplane unit cell, the drive signal being generated based on the power signal and configured to adjust one or more operating characteristics of the selected light emitting element. The method of claim 10 , wherein the selection signal is aligned with a frame operation of the display.

12. The method according to claim 11, further comprising: receiving a next selection signal; as well as Within the backplane unit cell, a next value of a data signal is stored on the storage element in response to receiving the next select signal, wherein the select signal and the next select signal are aligned with a frame operation of the display.

13. The method of claim 10, wherein the one or more operating characteristics of the selected light emitting elements include one or more of the following: bandwidth, Current, Gamma correction, or Dynamic range. 14 . The method of claim 10 , wherein generating the driving signal comprises generating a pulse signal with a variable width to adjust the one or more operating characteristics of the light emitting element.

15. The method of claim 10, wherein the reference signal and the power signal are applied at the same time during a frame operation of the display and after a data signal for the frame operation has been provided to a corresponding backplane unit cell including the backplane unit cell.

16. A display device, comprising: a display having a plurality of light emitting elements arranged in a passive matrix topology; The apparatus of any one of claims 1 to 9, wherein the backplane is configured in an active matrix topology including a plurality of data columns and a plurality of row selects; as well as A set of electrical contacts is associated with the active matrix topology and is configured to electrically couple the backplane to the display.

17. The display device of claim 16, wherein each of the data columns and each of the row selections are directly accessible via one or more edges of the backplane.

18. The display device according to claim 16, further comprising a plurality of backplane unit cells, wherein: Each backplane unit cell is connected to one of the data columns and one of the row selects in the backplane, and Each backplane unit cell is configured to connect to a subset of light emitting elements in the display via corresponding electrical contacts.

19. The display device of claim 16, wherein each electrical contact in the set of electrical contacts comprises a bonding site.

20. The display device of claim 16, wherein each of the plurality of light emitting elements is a light emitting diode lacking a dedicated driving unit.

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