High density pixel arrays for auto-viewed 3D displays

Abstract

A display device based on microLEDs includes a plurality of small chips. Each small chip includes one or more light pixels, and each light pixel includes a plurality of microLEDs supported on a substrate. The small chip also includes a micro-integrated circuit (microIC) electrically connected to the one or more light pixels. The microIC includes a plurality of interconnects supported on a substrate, such that when connected to a light pixel, the microIC can be used to electrically drive each of the microLEDs in the light pixel. In an embodiment, the plurality of small chips are disposed on a display substrate for use in an auto-viewing horizontal parallax-only 3D display.

Description

[Technical Field]

[0001] None [Previous Technology]

[0002] Various types of displays have been proposed to provide naked-eye stereoscopic (i.e., viewing without glasses or near-eye optics, or "auto-viewing") three-dimensional (3D) displays. One type of such auto-viewing 3D display is called a horizontal parallax-only (HPO) display, a biconvex lens display, a raster barrier display, or a parallax barrier display, combining various methods of separating different parallax views in one dimension (e.g., horizontal). These displays combine apertures or lenses to multiplex a two-dimensional (2D) pixel array to specific and limited viewing angles, thereby enabling the presentation of different parallax or animation sequence scene views to each eye. For example, the number of discrete parallax view channels is determined by the field angle of the biconvex lens used in the display, the spacing between pixels and the lens or aperture, the width of the lens or aperture, and the pixel size. Examples of existing autoviewing 3D displays are described in U.S. Patent Publication No. 2016 / 0234487 A1 by Kroon et al. and No. 2017 / 0208319 A1 by Kim et al.

[0003] When the view allocation is limited to the horizontal direction, the number of different samples in the horizontal direction in a pixel layer is at least twice as large, and sometimes as much as one hundred times or more, than the number of different samples in the vertical direction. Standard display technologies, such as those based on organic light-emitting diodes (OLEDs) or liquid crystals (LCs), are limited in the minimum size of pixels, and therefore the lens size or aperture spacing is also limited, as the pixel size is constrained by the required display brightness and the actual size of the pixel driving circuitry. Some trade-offs have been utilized, although at the cost of sacrificing display vertical resolution, by using tilted biconvex lenses (see Kroon et al., as described above) and pixels from several vertical columns (see Kim et al., as described above) to increase the number of horizontal angles and the allocation span, while potentially reducing crosstalk.

[0004] A solution is needed to overcome such problems in existing display systems. [Summary of the Invention]

[0005] The following is a simplified summary of one or more patterns to provide a basic understanding of these patterns. This summary is not a comprehensive overview of all anticipated patterns, nor is it intended to identify key or important elements of all patterns, nor is it intended to depict the scope of any or all patterns. Its purpose is to present some concepts of one or more patterns in a simplified form as a prelude to the more detailed descriptions that follow.

[0006] In an embodiment, the display device based on a micro light emitting diode (microLED) includes a plurality of small chips. Each small chip includes one or more light pixels, and each light pixel includes a plurality of microLEDs supported on a substrate. The small chip also includes a micro integrated circuit (microIC), which is electrically connected to one or more light pixels. The microIC includes a plurality of interconnects supported on a substrate, such that when connected to a light pixel, the microIC can be used to electrically drive each of the microLEDs of the light pixel. In one embodiment, the plurality of small chips are disposed on a display substrate for use in an auto-viewing horizontal parallax-only 3D display.

Implementation Method

[0017] The invention will now be described more fully with reference to the accompanying drawings, in which embodiments of the invention are shown. However, the invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for clarity.

[0018] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or portion from another region, layer, or portion. Therefore, the first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of the present invention.

[0019] For ease of description, spatial relative terms such as “below,” “under,” “lower,” “below,” “above,” “upper,” and similar terms may be used herein to describe the relationship between one element or feature illustrated in the figures and another element(s). Spatial relative terms are intended to cover different orientations of the device in use or operation other than those depicted in the figures. For example, if the device in the figures is flipped, it is described as an element of another element or feature “below,” “below,” or “below.” Thus, the exemplary terms “below” and “below” may cover above and below orientations. The device may be otherwise oriented (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein may be interpreted similarly accordingly. Furthermore, it should be understood that when a layer is referred to as “between” two layers, it may be the only layer between the two layers, or there may be one or more intermediate layers.

[0020] The terminology used herein is for describing particular embodiments only and is not intended to limit the invention. As used herein, unless the context clearly indicates otherwise, the singular forms "a," "an," and "the" are intended to include the plural forms as well. It should be further understood that when the terms "comprises" and / or "comprising" are used in this specification, the presence of the stated features, integers, steps, operations, elements, and / or components is specified, but the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof is not excluded. As used herein, the term "and / or" includes any and all combinations of one or more related listed items and may be abbreviated as " / ".

[0021] It should be understood that when an element or layer is referred to as being "on," "connected to," "coupled to," or "adjacent to" another element or layer, it may be directly on, connected to, coupled to, or adjacent to that other element or layer, or an intermediate element or layer may be present. Conversely, when an element is referred to as being "directly on," "directly connected to," "directly coupled to," or "immediately adjacent to" another element or layer, no intermediate element or layer exists. Similarly, when light is received or provided "from" an element, it may be directly received or provided from that element or intermediate element. On the other hand, when light is received or provided "directly from" an element, no intermediate element exists.

[0022] Embodiments of the present invention are described herein with reference to cross-sectional views that serve as schematic diagrams of idealized embodiments (and intermediate structures) of the invention. Therefore, variations in the illustrated shapes are expected due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of the invention should not be construed as limited to the specific shapes of the regions shown herein, but should include, for example, shape deviations caused by manufacturing processes. Thus, the regions shown in the figures are essentially schematic, and their shapes are not intended to illustrate the actual shapes of the regions of the device, nor are they intended to limit the scope of the invention.

[0023] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms such as those defined in common dictionaries shall be interpreted as having a meaning consistent with their meaning in the context of the relevant art and / or this specification, and shall not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0024] To produce a high-brightness autoviewing 3D HPO display (e.g., biconvex lens-shaped or grating barrier-based), the pixel density should be relatively high compared to the lens size and / or aperture spacing. Furthermore, the luminous flux of the display should be equal to or greater than that of its 2D counterpart. These requirements are inherently impractical and conflicting for organic light-emitting diodes (OLEDs) and liquid crystal-based displays (LCDs), as the minimum pixel size of such displays is constrained by brightness requirements, pixel layer physics, the practical circuit density limitations of the necessary thin-film transistor (TFT) or low-temperature polycrystalline silicon (LTPS) substrate circuitry, and, in the case of LCDs, the basic backlighting requirements for each pixel. For example, for existing displays, these constraints, along with TFT and LTPS scaling constraints, limit the size of red-green-blue (RGB) pixels to approximately 30 micrometers by 30 micrometers (e.g., the Premium OLED display on the Sony Xperia Z5), approximately 50 micrometers by 50 micrometers (e.g., the Liquid Retina display on the Apple iPhone 11), and up to approximately 110 by 110 square micrometers (e.g., the Retina display on the Apple MacBook).

[0025] While complementary metal-oxide-silicon (CMOS) substrates can provide higher density pixel driving circuitry systems, exceeding 10,000 pixels per square inch, silicon-based CMOS substrates are more expensive than TFT or LTPS substrates. Laying out large-scale LC or OLED display panels using CMOS substrates is not cost-effective. Furthermore, the mechanical tolerances in the alignment of high-density display pixels with respect to lenses or apertures can be problematic. Lenses or apertures are generally formed individually from large display pixels using techniques such as injection molding, extrusion, or printing, and applied to the display pixels using, for example, pressure-sensitive adhesives. All of these processes are inherently limited by mechanical tolerances on the order of tens of micrometers. If the number of pixels behind each lens / aperture is limited, and the ratio between the lens / aperture size and the pixel size is in the single digits, unwanted artifacts related to misalignment between the lens / aperture and the pixel cannot be compensated for by calibration or software. The large area of ​​a display compared to pixel and lens / aperture sizes exacerbates these problems, as tolerance errors accumulate from one side of the display to the other or from the center to the edges during manufacturing. Combined with these limitations in manufacturability, brightness, and driving circuitry, producing high surface resolution, high angular resolution, and high brightness HPO autoviewing 3D displays using existing technologies is a challenging path.

[0026] In contrast, inorganic micro light emitting diodes (microLEDs) can produce high brightness from a small emitting area and have proven to be a viable display pixel source. For example, see International Patent Publications Nos. WO 2019 / 209945 A1, WO 2019 / 209957 A1, and WO 2019 / 209961 by He et al., all of which are incorporated herein by reference. The emission flux of a single microLED emitter has been shown to be several orders of magnitude higher than that of larger-area OLED devices, and also higher than the emission flux practically achievable using transmissive LC and backlighting. Therefore, the emergence of smaller, higher-density, brighter, and more efficient emitting pixels provides a unique solution to the above problems.

[0027] While the size limit of a visually recognizable pixel at a typical arm-length working distance is considered to be approximately 150 micrometers (i.e., corresponding to approximately 1 arcminute / pixel), microLEDs offer extremely bright light emission in a fraction of that size. For example, a 10-micrometer by 10-micrometer square microLED can emit up to 1,000 times the luminous flux of a 10,000-square-micrometer OLED or LC pixel (e.g., 500,000 nits versus 500 nits). That is, emitters within a microLED display can be spaced apart so that full-color red-green-blue (RGB) pixel units can be located within a pitch of less than 3 micrometers, where all three colors can be emitted substantially simultaneously. Therefore, even while maintaining a total pixel size of 10,000 square micrometers, the required microLED luminous area is much smaller than that of OLED or LC pixels, while providing retina-limited resolution and even higher luminous flux.

[0028] Utilizing the aforementioned characteristics of microLEDs, a novel configuration for an autoviewing HPO 3D display is disclosed. Figure 1 illustrates a concept related to a display system incorporating microLEDs according to an embodiment. As shown in Figure 1, a microLED emitter array 100 includes a plurality of microLEDs supported on a wafer 104. As shown in illustration 108, microLEDs 110A, 110B, and 110C are configured in an array, each microLED having a pitch ranging from about 10 micrometers to sub-micrometer levels. For example, microLEDs with emitter pitches of several micrometers and providing light emission in the visible wavelength range with high brightness (i.e., about hundreds of thousands of nits) have been demonstrated. MicroLEDs 110A, 110B, and 110C can each emit light energy at wavelengths different from each other. For example, microLED 110A can emit in the red wavelength range, microLED 110B can emit in the blue wavelength range, and microLED 110C can emit in the green wavelength range. Note that although microLEDs of similar colors are shown in a row in Illustration 108, microLEDs can be configured in other ways, such as in pairs, clusters, and other suitable forms for specific applications, without departing from the scope of this document.

[0029] Referring again to Figure 1, a portion of the microLED emitter array 100 is isolated as clusters or "light pixels" 120. For example, light pixels 120 can be generated by cutting the microLED array 100 into multiple light pixels. As shown in Figure 1, light pixels 120 include one microLED 110A and one microLED 110B, and two microLEDs 110C, supported on a substrate portion 122 of wafer 104. Light pixels 120 are then electrically connected to a micro integrated circuit (microIC) 130. MicroIC 130 includes a plurality of interconnects 132 supported on a base plate portion 134, such that when connected to light pixels 120, microIC 130 can be used to electrically drive each of microLEDs 110A, 110B, and 110C. When the light pixel 120 is electrically connected to the microIC 130, they together form a "microchip" 135 with a total pitch of about 10 micrometers or less.

[0030] Finally, a plurality of small chips 135 can be transferred to a display substrate to form a microLED display 140, a portion of which is shown in Figure 1. The microLED display 140 includes a plurality of horizontal busbars 142 and vertical busbars 144 respectively supported on a display substrate 146. For example, since the pitch of each small chip 135 is about 10 micrometers or less, the distance between the small chips 135 can be 50 to 100 micrometers to keep the pixel size below the 150-micrometer size limit discussed above, while providing high brightness emission at one or more wavelengths to simplify electrical connections and to leave space on the display substrate 146 for additional components, such as sensor elements and other small electronic or optical elements. In addition, microlenses or other optical elements optically coupled to the light-emitting pixels in the display to guide the light-emitting pixels to the desired location have a size of about 100 micrometers. Therefore, such optical elements simplify the optical alignment system relative to the small chips 135 compared to conventional displays where the light-emitting elements occupy most of the pixel space. Similarly, since the microlens or optical element can easily cover the microchip 135, artifacts caused by shadows or edge effects due to the edge occlusion of the microLED 110 by the microlens or optical element are eliminated.

[0031] Although Figure 1 shows light pixels 120 cut from a dense microLED array 100, light pixels 120 may also be formed by transferring individuals or groups of microLEDs from the microLED array 100 onto a substrate portion 120. In one example, the microLED array 100 may include microLEDs emitting at different wavelengths, as shown in Figure 1, or all emitting at a single wavelength.

[0032] The concept of a chiplet (e.g., chiplet 135) is extended in the embodiment shown in Figure 2. As shown in Figure 2, a portion of the display 200 includes chiplets 202. Each chiplet 202 includes a light pixel 210, which in turn includes a plurality of microLEDs 212A, 212B, and 212C supported on a substrate portion 214. Note that each light pixel 210 includes a plurality of microLEDs arranged in a row (multiple), rather than four microLEDs as shown in Figure 1, which will be described in further detail in Figure 3 below. MicroLEDs 212A, 212B, and 212C are individual examples of microLEDs 110A, 110B, and 110C. Light pixel 210 is an example of light pixel 120.

[0033] Referring again to Figure 2, each of the microLEDs 212A, 212B, and 212C emits light, which can be collected and redirected by a structure such as a light cone 216. Each of the microLEDs 212A, 212B, and 212C includes an electrical connector 218 for electrical connection to the microIC 220 via an interconnect 222. The interconnect 222 is supported on a substrate portion 224. Next, the chiplet 202 is connected to the display substrate 230 via a connector 232. For example, the connector 232 may be conductive or non-conductive. Each chiplet 202 is covered with a multi-view optics 240, which works with the chiplet to guide the light emitted from the chiplet to the desired location. The combination of the chiplet 202 and the multi-view optics 240 forms a pixel 250, as shown in Figure 2.

[0034] Further details of an example of a small chiplet used in combination with a microlens array, according to an embodiment, are shown in Figure 3. As shown in Figure 3, the small chiplet 300 includes a light pixel 320, which includes a plurality of microLEDs (such as microLEDs 110A, 110B, and 110C in Figure 1) supported on a substrate portion 322. In the example shown in Figure 3, 17 microLEDs in two columns are arranged in the light pixel 320 to form a plurality of sub-light pixels 324. The light pixel 320 is used for electrical connection to a microIC 330, which in turn includes a plurality of interconnects 332 supported on a base plate portion 334. The light pixel 320 is an example of a light pixel 210.

[0035] Furthermore, as shown in Figure 3, the chiplet 300 includes a microlens array 350 for optical alignment with the light-emitting pixels 320. The microlens array 350 includes a plurality of microlenses 352, each of which, in one example, can be optically aligned with one of the microLEDs in the light-emitting pixels 320. Alternatively, each of the microlenses 352 can be resized and aligned to cover each of the sub-light-emitting pixels 324. For example, the microlens array 350 can be incorporated into the light-emitting pixels 320 such that the chiplet 300 includes microlenses integrated thereon. Note that the microlenses 352 may be physically and functionally different from conventional lenses or optical steering elements used to separate light from different sub-light-emitting pixels 324 to form different views. That is, the microlenses 352 can be considered as part of the chiplet 300 and can provide a set of separate lenses for forming multiple views formed by the overall 3D display.

[0036] Referring now to Figure 4, a portion of the display 400 includes a plurality of small chips 300 supported on a display substrate 410. The display substrate 410 includes a plurality of horizontal buses 412 and vertical buses 414, such that a portion of the display 400 includes a four-by-four pixel array, each pixel including a small chip 300. Each of the small chips 300 is driven by the horizontal buses 412 and the vertical buses 414 to contribute to one of the multiple views generated by the display 400, such as a first view 422 and a second view 424 displayed at the right eye 432 and left eye 434 respectively using, for example, an additional lens or optical steering element (not shown).

[0037] In an embodiment, each microLED emitter has a pixel pitch of approximately a few micrometers (e.g., less than 10 micrometers, less than 5 micrometers, or less than 3 micrometers), and the light pixel 320 is supported on a similarly small CMOS substrate for addressing each microLED, with each chip having an area as small as 10 micrometers by 60 micrometers. The resulting chip 300 may include a circuit system that interfaces with an addressing array (e.g., horizontal bus 412 and vertical bus 414, respectively) on the display substrate using a specific communication protocol. Alternatively, each chip 300 may be configured to be addressable by a simpler TFT or LTPS display driving circuit, thereby significantly reducing the cost and complexity of the resulting display compared to comparable OLED or LC displays. In some embodiments, the driving circuit system may include a de-scaling circuit, an interpolator circuit, a parallax sequencing circuit, or other circuitry for providing processing functionality. Furthermore, the remaining area of ​​the display substrate 410 not covered by the chip 300 may be filled with additional electronic or optical components, such as sensors or transistors.

[0038] According to an embodiment, Figure 5 shows an alternative layout of the chiplet. As shown in Figure 5, pixel unit 500 includes chiplets 510 supported on display substrate 512. Chiplet 510 includes light pixels 520, which in turn includes a substrate portion 522 on which a plurality of microLEDs 524A, 524B, and 524C are supported. Light pixel 520 is an example of light pixel 320. Although each of microLEDs 524A, 524B, and 524C is shown emitting different colors of light in Figure 5, other configurations of microLEDs are possible, such as all microLEDs emitting a single color, only two colors, or emitting a specific color, which is converted to additional wavelengths using a color converter configuration (not shown). Light pixel 520 is electrically coupled to microIC 530 (interconnects and other components of microIC 530 are not visible in Figure 5).

[0039] Figure 6 illustrates the application of pixel 500 according to Figure 5 of the embodiment. A magnified portion of display 600 is shown in Figure 6. The portion of display 600 shown in Figure 6 includes a four-by-four array of pixel units 500. In the embodiment shown in Figure 6, display 600 further includes an array of cylindrical lenses 620 covering the respective rows of pixel units of display 600, thereby providing a horizontally parallax-only viewing by uniquely mapping the light from the pixel pixels to different angles radiating in the horizontal direction. Alternatively, the cylindrical lenses 620 may be replaced or combined with parallax barriers that can function similarly to the cylindrical lenses. Thus, the individual pixel units 500 contribute to the view viewed by viewer 630 and represented by rays 632.

[0040] In this embodiment, each pixel unit 500 has a size of 150 micrometers by 150 micrometers or smaller, such that when viewed at a working distance of 500 millimeters, the span of the pixel unit is approximately 1 arcminute or smaller. Since the width of each lens 620 is below the perceptual limit of the viewer 630, and the microLED emitters on each chip 510 are even smaller than the width of each lens 620, the display 600 is capable of generating multiple output fields with different directions. Therefore, the display 600 is operated to provide a surface resolution perception equivalent to that of a state-of-the-art 2D display, with the ability to depict high-quality, auto-viewing 3D images.

[0041] An alternative pixel configuration using linear microchips similar to those shown in Figures 5 and 6 is discussed with reference to Figures 7 through 10. Figure 7 shows a pixel 700 including a base plate 710 on which a circuit system 712 is supported. Note that while the circuit system 712 is intended to represent a general concept of electronic components supported on the base plate 710, it does not represent a specific circuit diagram in terms of components or dimensions. Pixel 700 also includes a monochrome first microchip 722, a second microchip 724, and a third microchip 726. Each of the first microchip 722, the second microchip 724, and the third microchip 726 can be formed independently and coupled to the base plate 710. As an example, the first microchip 722 includes two rows of microLEDs emitting in the red wavelength range. The second microchip 724 includes one row of microLEDs emitting in the green wavelength range, and the third microchip 726 includes one row of microLEDs emitting in the blue wavelength range. For example, the first small chip 722 includes an additional column of red-emitting microLEDs to compensate for the typically lower efficiency and brightness of red microLEDs compared to currently available green or blue-emitting microLEDs. Pixel 700 is covered by a portion of a cylindrical lens 730 for guiding light from pixel 700 to desired locations to contribute to the multiple views provided by the overall display including pixel 700.

[0042] Figure 8 shows another variation of the pixel using linear microchips. As shown in Figure 8, pixel 800 includes many of the same components as pixel 700 in Figure 7, wherein the circuit system 712 is representative rather than specific in terms of the electronic components that can be supported on the base plate 710. However, pixel 800 includes a tri-color microchip 820, which includes three columns of microLEDs, each column of microLEDs emitting in a specific wavelength range, such that each vertical column of microLEDs provides three different colors of light emission. This columnar configuration differs from the hexagonal package structure shown in Figure 5 and enables higher density packaging of the emitters and variable spacing between colors (optional). In this case, all three columns of microLED emitters are driven as a single microchip.

[0043] Figure 9 illustrates another variation of the linear microchip pixel, used here to increase the density of different parallax output fields. Similarly, the circuit system 712 shown in Figure 9 is intended to represent a general concept of electronic components supported on the base plate 710, rather than indicating a specific circuit diagram in terms of components or dimensions. As shown in Figure 9, pixel 900 includes a first microchip 922, which includes two rows of tri-color microLEDs forming a row of sub-ray pixels 924. The sub-ray pixels 924 are an example of the sub-ray pixel 324 in Figure 3. In the example shown in Figure 9, each sub-ray pixel 924 includes at least one microLED emitting light in the red wavelength range, at least one microLED emitting light in the green wavelength range, and at least one microLED emitting light in the blue wavelength range. Although Figure 9 shows a 2x2 microLED array, other layouts and light emission combinations are also possible.

[0044] Continuing with reference to Figure 9 and Figure 10, pixel 900 further includes a second microchip 932, and also includes two columns of tri-color microLEDs forming a column of sub-pixels 934. The second microchip 932 is offset from the first microchip 922 by half a sub-pixel, as shown in the example in Figure 9. In one example, the leftmost sub-pixel of the first microchip 922 is used to provide the leftmost portion of the view, the leftmost sub-pixel of the second microchip 932 is used to provide the second leftmost portion of the view, and so on, as shown in Figure 10. That is, if the display device 1010 is formed by a plurality of pixels 900, then the view 1020 seen by the viewer 1030 is a combination of views 1, 2, 3, 4, ... (displayed as numbers adjacent to sub-pixels 924 and 934 corresponding to the first microchip 922 and the second microchip 932, respectively) provided by sub-pixels 1, 2, 3, 4, ... (forming view 1020 as shown in Figure 10). In this way, the parallax views provided by the first chiplet 922 and the second chiplet 932 can be interleaved, increasing the horizontal parallax sampling beyond the pixel pitch limit. Therefore, compared to using a single chiplet, two chiplets can be used to generate higher angular resolution for a given pixel pitch. A similar method can be applied to parallax barrier-based display systems in which chiplets are combined.

[0045] A further variation of the chiplet concept is shown in Figure 11. As shown in Figure 11, pixel 1100 includes a first chiplet 1110A and a second chiplet 1110B. The first chiplet 1110A is horizontally oriented along the top edge of pixel 1100 and includes a light pixel 1120. The light pixel 1120 is an example of the light pixel 120 in Figure 1. As described above, the light pixel 1120 is electrically coupled to a microIC (not visible in Figure 11). The light pixel 1120 includes a substrate portion 1122 on which a row of sub-light pixels 1124 are supported. Each sub-light pixel 1124 includes a first microLED 1126A, a second microLED 1126B, and a third microLED 1126C. In the example shown in Figure 11, the first microLED 1126A, the second microLED 1126B, and the third microLED 1126C emit light in different wavelength ranges, such as red, green, and blue wavelength ranges as examples. The first microchip 1110A is covered by a lens 1130. Alternatively, a parallax barrier may be provided to replace or supplement the lens 1130. The second microchip 1110B includes substantially the same components as the first microchip 1110A and is oriented vertically along the left edge of the pixel 1100, as shown in the exemplary embodiment of Figure 11.

[0046] The orthogonal orientation of the first chip 1110A and the second chip 1110B enables the pixel 1100 to provide a horizontally parallax-only 3D view even when the display is rotated. For example, if the display device incorporating the pixel array also includes a gyroscope, the display device can use the first chip 1110A only when the display device is in a first position, and deactivate the first chip 1110A and activate the second chip 1110B when the display device senses that it has rotated 90 degrees into a second position. This feature would be suitable for, for example, cellular phones or tablet computers that can provide an automatically viewing horizontally parallax-only view when the device is in portrait or landscape mode.

[0047] The additional space available in pixel 1100 can be used in a variety of ways. In an embodiment, pixel 1100 of Figure 11 further includes a single RGB emitter 1140. The single RGB emitter 1140 includes a substrate portion 1142 supporting sub-pixel 1144. While the substrate portion 1142 is shown as square, other shapes (e.g., hexagonal) can be used for specific applications. Sub-pixel 1144 includes a first microLED 1146A emitting light in the red wavelength range, a second microLED 1146B emitting light in the green wavelength range, and a third microLED 1146C emitting light in the blue wavelength range. For example, the single RGB emitter 1140 can be used to display standard (i.e., parallax-free) 2D images, thus eliminating the need for multi-view optics integrated thereon. The single RGB emitter 1140 can be used to display 2D images when the display device incorporating pixel 1100 is not used to display 3D images. Alternatively, 3D and 2D modes can be activated simultaneously, allowing 2D images to be displayed on the surface of the display device, while 3D images or specific portions of 2D images can be displayed as 3D objects floating above or below the surface of the display device. Additionally, extra electronic or optical components can be incorporated into the available area of ​​pixel 1100. For example, one or more sensors can be incorporated into pixel 1100 to perform tasks such as brightness sensing, motion sensing, depth sensing, and head / eye / gaze tracking.

[0048] Figures 12 through 14 illustrate alternative display architectures incorporating the chiplet concept. As shown in Figure 12, a portion of the display 1200 includes a plurality of lenses 1210 arranged in adjacent rows. A plurality of chips 1220 are directly attached to each lens 1210, rather than being supported on a display substrate. The array of lenses 1210 also includes signal conduction bus lines 1230 embedded between the optically active areas of the lenses 1210 and connected to each chiplet 1220 via branch conductors 1232. For example, the bus lines 1230 and branch conductors 1232 may be embedded within the lenses 1210 or printed onto the surface of the array of lenses 1210 using screen printing, metal deposition, or other suitable methods. Laterally adjacent chips may be offset from each other as shown in Figure 12, or aligned as shown in Figure 6.

[0049] Figure 13 shows a side cross-sectional view of a portion of the lens 1210 incorporating the chiplet 1220. As shown in Figure 13, as an example, the chiplet 1220 can be held in place by a mounting feature 1310. The mounting feature 1310 may be a clip-like feature for securely accommodating at least a portion of the chiplet 1220 therein, and may be molded during the manufacture of the chiplet 1210 or added after the manufacture of the chiplet 1210. The mounting feature 1310 may also incorporate electronic wiring for connecting the chiplet 1220 to the branch conductor 1232.

[0050] Top cross-sectional views of different portions of the lens array 1210 are shown in Figure 14. As shown in Figure 14, the microchip 1220 is attached to the lens 1210 and electrically accessed via the conductive bus 1230. As an illustrative example, as shown in Figure 14, the first portion of the upper microchip 1220 emits light, indicated by solid arrow 1410, which is guided downwards in the figure by the curvature of the lens 1210. Similarly, a different second portion of the same upper microchip 1220 emits light, indicated by dashed arrow 1412, which is guided upwards in the figure by the curvature of the lens 1210, thereby providing a different view from the first portion of the upper microchip 1220 and producing a horizontal parallax-only view.

[0051] In the configuration shown in Figures 12 to 14, the lens array 1210 (i.e., the optical layer) becomes a structural element of the display device without the need for a display substrate, thereby enabling a thinner display. Furthermore, this architecture facilitates higher-precision alignment of the chiplet 1220 with its associated optical elements, thereby reducing optical aberrations and image artifacts. Additionally, it more effectively isolates the light emission fields between pixels, thereby reducing display crosstalk and further enhancing image quality. Moreover, the manufacturability of the display device can be improved, for example, by constructing each column of lenses as strips in which chiplets and branch conductors are integrated, and then assembling the display device row by row from the strips. Those skilled in the art will understand that the same approach can be used to integrate parallax barriers, rather than lenses or a combination of both.

[0052] Figures 15 and 16 illustrate another configuration of this microchip directly integrated with the lens. As shown in Figure 15, the flat panel display 1500 provides a horizontal parallax view to the viewer 1510. The flat panel display 1500 includes microchips 1530 supported by rows of lenses 1540. In the center of the flat panel display 1500, with the viewer 1510's eye socket vertically aligned with the flat panel display 1500, microchips 1530A reliably provide a parallax view with low aberrations. However, for example, when microchips 1530B and lenses 1540B are still aligned with the plane of the flat panel display 1500, extreme off-axis operation of the display near the edges of the flat panel display 1500 may cause visual artifacts and optical aberrations in the view presented to the viewer 1510.

[0053] Conversely, if the flat panel display is formed from strips of lenses in which small chips are integrated, and assembled row by row as described above, the orientation angles of each row of lenses (and correspondingly the orientation angles of the small chips integrated therein) can be adjusted from the center to the edge of the display to mitigate aberrations caused by the display architecture shown in Figure 15. For example, as shown in Figure 16, the small chip 1630B and lens 1640B near the center of the display can be rotated a certain amount toward the central axis, and the small chip 1630C integrated in lens 1640C near the edge of the flat panel display can be further rotated toward the central axis of the display (e.g., rotated 31 degrees), and so on. By rotating the rows of lenses and their associated small chips so that each lens faces the center of the desired eye socket, edge effects and other optical aberrations can be reduced.

[0054] A further alternative is to assemble the lens strips integrating the microchips into a curved display. As shown in Figure 17, the curved display 1700 is used to provide a horizontal parallax view to the viewer 1710. Within the curved display 1700, the curvature of the display causes the lenses, and thus the microchips integrated therein, to bend toward the eye socket of the viewer 1710 as shown in the figure.

[0055] Another display architecture, as shown in Figures 18 through 20, illustrates an alternative type of lens and a conformally curved emitter strip. For example, a Luneburg lens with a graded refractive index varying from the center to the periphery is designed to have a conjugate focal point at infinity and produce a high-quality transformation at the lens surface. As shown in Figure 18, the lens portion 1800 includes a graded-index Luneburg cylindrical lens 1810 on which a curved microcrystal 1820 is integrated.

[0056] A top cross-sectional view of the lens portion 1800 is shown in Figure 19. As shown in Figure 19, the lens 1810 is supported by a pre-bed 1910, which also includes a conductive bus 1920 for electrical coupling with the curved wafer 1820. Due to the refractive properties of the Luriber lens, light from different portions of the curved wafer 1820 produces collimated outputs, appearing from opposite surfaces, as represented by rays 1950 and 1955. Alternatively, the curved wafer 1820 can be integrated into the pre-bed 1910 to conformally contact the lens 1810 as shown in Figure 19. Furthermore, as shown in Figure 20, multiple lenses 1810 can be arranged in a row to form a display. For example, each of the curved wafers 1820 can be addressed via the bus 2010. Due to the high-quality optical performance of the Luriber lens at large angles, this Luriber method has the advantage of providing a larger field of view. This method can also provide relatively simple optical components in the manufacturing process.

[0057] While the above discussion focuses on displays based on lenses or biconvex lenses, it is recognized that these discussions are also readily applicable to parallax / grating barriers and aperture-based displays. The microLED chiplet approach for providing automated viewing 3D displays fundamentally separates the large pixel bed of the display from the parallax-generating optics by discretizing individual pixel unit emitters into their respective modules. This approach, combined with high-speed, high-resolution pick-and-place assembly systems or monolithically integrated microLED manufacturing, enables display structures and system architectures that were previously unavailable. The ratio between pixel size and pitch, lens size and pitch, lens field of view (or distribution angle), and lens focal length can be adjusted and optimized for various display applications, such as small-sized wearable displays, ultra-high-resolution displays, and large displays. Furthermore, the positioning of the emitters within the chiplet can be varied to meet the needs of specific display systems. For example, appropriate microLED layout schemes can be used to achieve non-linear spacing of parallax views or compensation for optical distortion caused by lenses.

[0058] Various alternative or additional configurations or components may be implemented in one or more of the above optical systems. Therefore, many different embodiments are derived from the above description and drawings. It should be understood that a literal description and illustration of the various combinations and sub-combinations of these embodiments would be unduly repetitive and obscure. Therefore, this specification (including the illustrations) should be interpreted as constituting a complete written description of all combinations and sub-combinations of the embodiments described herein, as well as the manner and process of their manufacture and use, and should support the scope of any patent application for any such combinations or sub-combinations. [Simplified Explanation of the Diagram]

[0007] The accompanying drawings only illustrate some implementations and should not be considered as limiting the scope.

[0008] Figure 1 illustrates the display system configuration according to an embodiment.

[0009] Figure 2 illustrates the pixel configuration of a display system including an alternative architecture according to an embodiment.

[0010] Figures 3 and 4 illustrate an alternative display system configuration according to an embodiment.

[0011] Figures 5 and 6 illustrate another variation of the pixel configuration of the display system according to the embodiment.

[0012] Figures 7 through 10 illustrate additional variations of the pixel configuration of the display system according to a further embodiment.

[0013] Figure 11 illustrates another alternative embodiment of the system pixel configuration.

[0014] Figures 12 to 14 illustrate another exemplary display system configuration according to an embodiment.

[0015] Figures 15 to 17 illustrate an additional display system configuration according to a further embodiment.

[0016] Figures 18 to 20 illustrate yet another display system configuration according to an embodiment. [Biomaterial Storage]

[0060] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A display system comprising: a plurality of chiplets, each chiplet including a chiplet comprising a plurality of miniature light-emitting diodes aligned along a direction; the chiplet having a width dimension orthogonal to the direction, the width dimension being greater than a height dimension aligned along the direction; a display substrate subdivided into a plurality of pixel units, at least one of the plurality of pixel units configured to support the chiplet; and a steering element optically coupled to the chiplet and configured to guide light along a first portion of a direction from a first portion of the chiplet and a second portion of a direction from a second portion of the chiplet.

2. The display system as claimed in claim 1, wherein the plurality of micro-light-emitting diodes are arranged in a micro-light-emitting diode array, the micro-light-emitting diode array having a micro-light-emitting diode pitch of less than 10 micrometers between adjacent micro-light-emitting diodes.

3. The display system as claimed in claim 1, wherein the plurality of small chips are configured as a two-dimensional chip grid having a chip pitch of less than 150 micrometers between adjacent small chips.

4. The display system as claimed in claim 1, further comprising: a sensor disposed on a portion of the display substrate between adjacent chips of the plurality of chips, the sensor including at least one of a brightness sensor, a motion sensor, a depth sensor, an eye sensor, and a gaze tracking sensor.

5. The display system as claimed in claim 1, wherein the steering element is included in a steering element array having a steering element pitch of less than 150 micrometers between adjacent steering elements.

6. The display system as described in claim 1, wherein the steering element is a lens.

7. The display system as claimed in claim 6, wherein the lens has a width dimension of approximately 100 micrometers.

8. The display system as claimed in claim 1, comprising at least one pixel unit of the plurality of pixel units in the display substrate supporting a first chiplet and a second chiplet of the plurality of chiplets.

9. The display system as claimed in claim 1, wherein the plurality of miniature light-emitting diodes includes a red emitter, a green emitter, and a blue emitter.

10. The display system as claimed in claim 1, wherein the steering element includes a cylindrical lens.

11. The display system as described in claim 1, wherein the steering element includes a parallax barrier.

12. The display system as claimed in claim 1, wherein when viewed from a distance of 500 mm, at least one of the plurality of pixel units spans one arcmin or less.

13. The display system as claimed in claim 1, wherein the plurality of pixel units comprises a pixel pitch of less than 150 micrometers.

14. The display system as described in claim 1, wherein the steering element is configured to define a parallax view.

15. The display system as claimed in claim 1, wherein the plurality of small chips is a first plurality of small chips, the direction is a first direction, the plurality of micro-light-emitting diodes is a first plurality of micro-light-emitting diodes, and the display system further comprises: A second plurality of small chips, comprising the second plurality of micro light-emitting diodes aligned along one of the second directions not parallel to the first direction.

16. The display system as claimed in claim 15, wherein the steering element is a first steering element and the second plurality of wafers are optically coupled to a second steering element.

17. The display system as described in claim 15, wherein the first direction is orthogonal to the second direction.

18. A display system comprising: a plurality of small chips, each including a small chip including a plurality of micro light-emitting diodes aligned along a line, the small chip having a width dimension orthogonal to the line, the width dimension being greater than a height dimension aligned along the line; a display substrate subdivided into a plurality of pixel units, at least one of the plurality of pixel units configured to support the small chip; and a steering element optically coupled to the small chip and configured to guide light along a first portion of a line from a first portion of the small chip and along a second portion of a line from a second portion of the small chip.

19. The display system as claimed in claim 18, wherein the small chip is electrically coupled to a micro-integrated circuit board, which is electrically coupled to the display board.

20. A display system comprising: a plurality of microchips, each microchip including a plurality of microlight-emitting diodes aligned along a line, the microchip having a width dimension orthogonal to the line, the width dimension being greater than a height dimension aligned along the line; a display substrate subdivided into a plurality of pixel units, at least one of the plurality of pixel units configured to support the microchip; and a steering element optically coupled to the microchip and configured to guide emission from one of the first microlight-emitting diodes at a first angle and to guide emission from one of the second microlight-emitting diodes at a second angle different from the first angle.

21. The display system as claimed in claim 20, wherein the emission from the first micro-light-emitting diode and the emission from the second micro-light-emitting diode correspond to a parallax view.

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