Surface mount components including multiple pixels and sub-pixels

Abstract

Disclosed is a light-emitting surface-mount component and method for manufacturing the same, which comprises an array of light emitters forming multicolor and white pixels, where the multicolor pixels have at least substantially the same overall pixel height and width as the white pixels in the array, thereby improving visual uniformity. The pixels comprise light emitters, such as LEDs, surface-mounted to a substrate to form a microarray. The microarray can be assembled into easily repairable light emitter tiles, which can be assembled into multi-tile video displays.

Description

Technical Field

[0001] Related Application Data This application claims the benefit of priority from U.S. Provisional Patent Application No. 63 / 012,984, filed on April 21, 2020 and entitled "Surface Mount Device (SMD) Comprising at Least a Plurality of Pixels and Sub-Pixels of Red, Green, Blue and White", the entire content of which is incorporated herein by reference.

[0002] The present disclosure generally relates to the field of LED packages. In particular, the present disclosure is directed to embodiments of a surface mount device (SMD) comprising at least a plurality of pixels and sub-pixels of red, green, blue and white.

Background Art

[0003] Video displays using light emitting diodes (LEDs) as light sources face significant challenges as resolution increases and the spacing between pixels decreases. In addition, not only are there physical challenges caused by the reduced spacing, but the small spacing also causes problems when modular tiles are adjacent to each other, increasing the possibility of physical damage during installation. Robustness and repairability of display modules are important, and these two attributes are often a trade-off against each other.

[0004] To make a display ultimately repairable, each circuit board with an LED array is composed of SMD_LED packages of a single pixel (or an even number of subpixels). For example, in a 100x100 pixel array on a circuit board, 100x100 RGB_SMD_LEDs can be used. This allows a single damaged pixel to be replaced without affecting the rest of the array. In an extreme example, assuming each pixel consists of at least one red, green, and blue, 300x300 individual subpixel SMDs could be used in the array. Even if a single subpixel is damaged, the damaged subpixel can be replaced without affecting the other subpixels. These two described methodologies have been used in the LED industry for over 20 years.

[0005] To make the display as robust as possible, it is typical to consider the use of a potting compound to cover the top of the LED array. The LED array can be made from individual SMD pixels, as in the previous example, or it can be a chip-on-board (COB) process where the diode chips are mounted directly onto the circuit board, as shown in Figure 7. In either case, a self-leveling epoxy or silicone can be placed over the entire array to make it rugged and robust. This results in a very durable array front that can withstand moderate impacts and scratches. However, the corners and edges of the array remain susceptible to impact, and when impact occurs, the mechanical properties of the sealant typically damage the RGB pixel group rather than a single pixel. Furthermore, due to the nature of the sealant as a curing adhesive, it is generally impossible (or reasonably, commercially) to repair damaged pixels. Moreover, if pixels could actually be repaired, the sealant should obviously not be reapplied in a way that prevents reapplication (i.e., the repaired surface would look different from the rest of the array). This means that if a single pixel in a 100x100 pixel array is damaged, the entire array becomes unusable. Furthermore, this means that just one damaged pixel necessitates discarding 9,999 good pixels. This is extremely inefficient, wasteful, and harmful to the environment. Another drawback of these conventional techniques is that when multiple arrays are arranged to form a large display, the edges of adjacent arrays can be very noticeable, similar to the grout boundaries in architectural / building material tiles.

[0006] Another obstacle in creating displays where pixels are very close together is that soldering the required number of red, green, and blue (and possibly white or other subpixel colors) subpixels to the PCB in an array is extremely time-consuming, even with the fastest automated machinery. In addition, when the screen resolution has a pixel pitch smaller than human vision, it may not be necessary to have all subpixel elements at each single pixel location. This allows the subpixel colors to be assimilated into halftone printing, where they are spaced in a known pattern, producing a perceptible image when viewed from a certain distance. Many LCD or OLED monitors arrange subpixels in a non-linear array or add another color to facilitate the special arrangement of pixels or contribute to the display's achievable color gamut. [Overview of the project] [Problems that the invention aims to solve]

[0007] In light of these challenges, there is still a need in the art for easily configurable and repairable flexible solutions for creating LED tiles, particularly for the creation of tile-type LED displays and large video wall-type LED displays. [Means for solving the problem]

[0008] To address the challenges presented by conventional designs, in some embodiments, a light-emitting surface-mount component includes a microarray of self-emissive pixels, each having a pair of polychromatic emitters in adjacent pixels and at least one white emitter of substantially equal height and width. The microarray comprises at least two horizontal pixels and two vertical pixels. Preferably, at least two pixels each have one white emitter, and at least two pixels each have the polychromatic emitters, which may be red / green / blue emitters forming a pair of subpixels. In some alternative embodiments, the component may comprise a microarray substrate having each emitter surface-mounted on a microarray substrate. In other alternative embodiments, the component may comprise a microarray substrate to which each polychromatic emitter is directly bonded, and a white emitter substrate having white emitters directly bonded to a white emitter substrate. In such latter embodiments, the white emitter substrate may be directly bonded to the microarray substrate.

[0009] In other embodiments, the light-emitting surface mount component includes a 2x2 pixel microarray having "a row consisting of a first pixel formed from one each of a red LED, a green LED, and a blue LED, and a second pixel formed from a single white LED" and "another row consisting of a first pixel formed from a single white LED, and a second pixel formed from one each of a red LED, a green LED, and a blue LED." Each pixel has the same overall height and overall width. Alternatively, other light-emitting material types such as OLED, PLED, AMOLED, LCD, or LEC may be used.

[0010] Further embodiments and features of the disclosed components include any configuration as a BGA package, QFN package, or PLCC package. In some embodiments, a light-transmitting encapsulation layer is arranged to cover the light-emitting element. In one preferred embodiment, the individual light-emitting surface mount components described above are 5 mm × 5 mm or less.

[0011] In further embodiments, the disclosed light-emitting surface mount components are arranged in an array on a tile substrate to form light-emitting tiles. In other disclosed embodiments, such light-emitting tiles may be assembled as an array to form a video display wall.

[0012] Furthermore, the challenges presented by prior art designs are addressed by the disclosed method for creating a light-emitting microarray. This method may comprise the steps of: configuring a plurality of polycolor pixels consisting of a set of polycolor light-emitting elements and having a total height and width r; surface mounting the polycolor pixels onto a microarray substrate; configuring a plurality of white light-emitting elements having a total height and width substantially the same as the height and width of each polycolor pixel; and surface mounting the white light-emitting elements onto the microarray substrate adjacent to the polycolor pixels to form a microarray in which polycolor pixels and white pixels alternate. In some embodiments, the method for creating a light-emitting microarray may further comprise the steps of first surface mounting the white light-emitting elements onto individual substrates, and then surface mounting the individual substrates having the white light-emitting elements onto a microarray substrate individually. In other embodiments, the method for creating a light-emitting microarray may further comprise sealing the light-emitting elements with a light-transmitting protective layer after surface mounting onto the microarray substrate. [Brief explanation of the drawing]

[0013] To illustrate this disclosure, the drawings illustrate aspects of one or more embodiments of this disclosure. However, it should be understood that this disclosure is not limited to the exact arrangements and means shown in the drawings. [Figure 1] Figure 1 is a partial schematic plan view of an LED tile according to an embodiment of the present disclosure. [Figure 2] Figure 2 is a schematic plan view of a microarray according to an embodiment of the present disclosure. [Figure 3] Figure 3 is a schematic cross-sectional view of a microarray according to an embodiment of this disclosure. [Figure 4] Figure 4 is a schematic cross-sectional view of a microarray according to another embodiment of the present disclosure. [Figure 5]Figure 5 shows the average visual acuity of adults as applied in the embodiments of this disclosure. [Figure 6] Figure 6 is a front view of an LED display according to this disclosure that utilizes tiles composed of a microarray disclosed herein. [Figure 7] Figure 7 is a partial schematic plan view of an example of a conventional LED tile. [Modes for carrying out the invention]

[0014] Embodiments disclosed herein utilize a microarray of RGB(N)+W(red / green / blue / (other possible colors)+white) pixels, reducing the need for more sets of RGB pixels than commercially viable using conventional techniques, while providing a more robust and durable array that facilitates the repair of light-emitting diode (LED) arrays and circuit boards that may be required due to component failure or physical damage. While RGB and white LED pixels are used herein for illustrative purposes as they are common configurations, the principles of this disclosure are equally applicable to any type of light-emitting diode that uses multicolor pixels, whether it be an RGB_LED type emitter, other types of emitters (e.g., in non-limiting examples, organic light-emitting diodes (OLEDs), polymer light-emitting diodes (PLEDs), active-matrix light-emitting diodes (AMOLEDs), liquid crystal displays (LCDs), or light-emitting electrochemical cells (LECs)), or other multicolor pixel combinations (e.g., in non-limiting examples, multi-primary color pixels having four or five colors such as RGBY, RGBM, RGBC, or RGBYC). Therefore, the scope of this disclosure and the accompanying claims is not limited to the exemplary RGB LED examples.

[0015] Figure 1 shows a portion of a tile 100 according to one embodiment of the present disclosure. The tile 100 comprises an array of microarrays 102 mounted on a suitable primary tile substrate 104, the primary tile substrate 104 may be, for example, a printed circuit board (PCB) or other suitable substrate. Examples of suitable substrates for the primary tile substrate 104 include standard PCB materials such as FR4, flexible circuit materials or foils, conductive fabrics, conductive glass, or metal circuit boards. As indicated by arrows X and Y along the edge of the tile substrate 104, the tile 100 may extend in the X and Y directions respectively as needed to form a desired tile size for a particular application. For example, the tile size may consist of a 10 × 10 array of microarrays 102, or a 100 × 100 array, or any size in between, or smaller or larger than that. For microarrays 102 positioned at the edges of a larger tile array 100, the spacing to the edges of the tile substrate 104 will be half the spacing between adjacent microarrays 102, providing a visually continuous appearance when multiple tiles 100 are adjacent to each other to form a video panel. Further spacing considerations are discussed below.

[0016] Details of individual microarray 102 embodiments are shown in Figures 2, 3, and 4. As shown in Figure 2, the microarray substrate 106 is mounted with eight LEDs that form four pixels (in other words, form a 2x2 pixel array that makes up a single microarray 102). In this example, two pixels each have one red LED 110, one green LED 112, and one blue LED 114, and two pixels each have one white LED 116. In one embodiment, each of the LEDs 110, 112, 114, and 116 is bonded directly to the substrate 106, as shown in Figure 3. In another embodiment, as shown in Figure 4, the RGB_LEDs 110, 112, and 114 are bonded directly to the substrate 106, while the W_LED 116 is formed on a separate substrate 120 and then bonded to the substrate 106. For example, the W LED 116 may be formed itself as an SMD package having a small blue light-emitting element (type), as described later, to excite an illuminating material such as a phosphor that covers all or substantially all of a designated area of ​​the LED 116, providing a white illuminated area of ​​appropriate size. In yet another embodiment, the RGB_LEDs 110, 112, and 114 themselves are surface-mounted on another substrate and then bonded to the substrate 106. The substrate 106 may comprise a standard PCB itself made from FR4 material or a similar material, or it may be a wafer substrate material such as sapphire, silicon, silicon carbide, or gallium nitride. As is commonly known in the art, the substrate 106 may comprise multiple layers, including, for example, a ceramic layer 122, a metal interconnect layer 124, and a lower layer 126 comprising elements such as a thermal pad and a cathode.

[0017] Another advantage of the embodiments disclosed herein is that the microarrays may be individually sealed with a light-transmitting protective sealing layer 128 covering the LEDs, as shown in Figure 3. Examples of materials for the sealing layer 128 include silicone or epoxy resin / sealing compounds, or insulating coating agents such as parylene, paraxylene, acrylic, silicone, polyurethane, or lacquer. Furthermore, lenses 130, such as epoxy or silicone lenses, may be optionally positioned to cover the entire microarray or to cover individual light-emitting elements or groups of light-emitting elements, as shown in Figure 4. In some embodiments, the sealing layer 128 may be used in conjunction with the lenses 130.

[0018] The embodiments described herein are, of course, suitable for various types of surface mount packaging, as they may be optimized for specific applications. For example, the embodiments disclosed herein may be provided as various types of flat leadless packages, such as ball grid array (BGA) packages and quad flat leadless (QFN) packages, or various chip carrier packages, such as plastic leaded chip carrier (PLCC) packages.

[0019] One feature of the embodiments disclosed herein is that the size of the white LED 116, i.e., the overall external dimensions (height and width), is at least substantially the same as the combined size (combined height and width) of the RGB_LEDs 110, 112, and 114, providing a smooth and consistent visual appearance under all lighting conditions. This means that, in various embodiments, the combined height and width of the multicolor pixels and the height and width of the white pixels vary from each other, if not identical, not exceeding about 1% to about 20% (within plus / minus 0%). In some embodiments, the combined height and width of the multicolor pixels are within about 5% to about 10% of the height and width of the white pixels.

[0020] The spacing and size of the microarrays 102 may be obtained based on the visual acuity of an observer. Typical visual acuity of an adult is 1 minute of arc or approximately 2 pixels per degree, as shown in FIG. 5. In general, the microarray size should be selected such that an observer does not perceive the boundaries of the microarrays. Parameters to be considered in sizing the microarrays 102 include an array size that is sufficiently large to provide improved durability and robustness, yet small enough that arrays on a PCB can be repaired.

[0021] As reflected in FIG. 5, the distance from the observer to the screen directly correlates to the ideal array size, and in general, pixel pitch is also selected based on this distance. In one example, a 100×100 pixel array may be formed in accordance with the present disclosure using an array of microarrays 102 having pixels as small as subpixels and 2×2 arrays, and as large as 16×16 arrays, such that the microarray size need not exceed 5 mm×5 mm. For a 2×2 microarray, the SMD footprint is four times more robust than a single RGB SMD pixel, yet sufficiently small that the array can be replaced for repair without being commercially impractical. It is also sufficiently small to fall within visual acuity such that an observer cannot see physical patterns or divisions in a very large array (in other words, the "texture" on the front surface of a very large display appears uniform).

[0022] In one example, the dimensions of the microarray 102 may be about 5 mm or less × 5 mm or less. For a 5×5 mm microarray, in some embodiments, the individual pixel size may range from about 2×2 mm to about 2.4×2.4 mm. By way of example, the white LED 116 may comprise a 6504 Kelvin or 2700 Kelvin LED. A further feature of the embodiments disclosed herein is that, as shown in FIG. 3, each microarray 102 may be individually sealed. Therefore, if an LED fails on one microarray, only that particular microarray needs to be replaced. And since any change in the sealing layer is contained within each microarray, the replaced microarray provides a more uniform appearance to the existing microarrays. Furthermore, when a single LED fails, only a single microarray, for example just eight LEDs in one embodiment, needs to be replaced, which is far more efficient and less wasteful compared to conventional designs.

[0023] FIG. 6 shows an example of a video display or a portion of a video display composed of the microarrays 102 disclosed herein. In this embodiment, the video display 140 comprises an array of tiles 100, each tile being composed of an array of microarrays 102. In this example, for illustrative purposes only, six tiles 100 are shown, each including sixteen microarrays 102. A typical real-world device will comprise a much larger array, as will be appreciated by those skilled in the art.

[0024] In addition to the array sizes described above, as explained above, the embodiments disclosed herein do not utilize a simple set of RGB for pixels. A white pixel 116 is added at at least one color temperature instead of one set of RGB. In other words, instead of attempting to further reduce subpixel spacing by adding another subpixel color, embodiments of the present disclosure replace three subpixels with fewer components but different colors. This may facilitate achieving higher efficiency and result in a uniform planar area white point for the video display.

[0025] The embodiments disclosed herein are A surface mount component comprising a microarray of self-emissive pixels, each containing a set of red / green / blue light-emitting elements in adjacent pixels and at least one white light-emitting element of substantially equal size in area, wherein the array has at least two horizontal pixels and two vertical pixels. • Surface mount component including multiple pixels and at least red, green, blue, and white subpixels • Surface mount components configured for use in surface mount technology processing. • Surface mount component equipped with a microarray of RGB+W light-emitting elements, with the microarray measuring 5mm x 5mm or less. Includes.

[0026] The above is a detailed description of exemplary embodiments of the present disclosure. Note that in this specification and the claims appended herein, connecting terms such as “at least one of X, Y, and Z” and “one or more of X, Y, and Z” mean, unless otherwise specified or indicated, that each item in the connecting list may exist in any number other than all other items in the list, or in any number combined with any or all other items in the connecting list, and each of these may also exist in any number. Applying this general rule, the connecting terms in the above examples where the connecting list consists of X, Y, and Z shall include each of “one or more X, one or more Y, one or more Z, one or more X and one or more Y, one or more Z, one or more X and one or more Y, and one or more Z.”

[0027] Various modifications and additions can be made without departing from the spirit and scope of this disclosure. Each feature of the various embodiments described above may be combined as necessary with features of other described embodiments to provide numerous feature combinations in any new embodiments relating to the present invention. Furthermore, although several distinct embodiments are described above, what is described herein is merely illustrative of the application of the principles of this disclosure. Furthermore, while certain methods herein may be illustrated and / or described as being performed in a particular order, the order is usually highly variable within the art to achieve the aspects of this disclosure. Therefore, this description is intended to be interpreted as an example only and is not intended to limit the scope of this disclosure.

[0028] Representative embodiments are disclosed above and shown in the accompanying drawings. Those skilled in the art will understand that various modifications, omissions, and additions can be made to the embodiments specifically disclosed herein without departing from the spirit and scope of this disclosure.

Claims

1. A microarray of at least four self-emissive pixels mounted on a microarray substrate in an array of at least 2x2, having at least two horizontal pixels and at least two vertical pixels, White light-emitting substrate and Equipped with, At least two of the pixels are white light-emitting pixels, and at least two of the pixels are multicolor pixels that include a set of multicolor light-emitting elements. The white light-emitting pixel includes at least one white light-emitting element having a height and width that is at least substantially equal to the sum of the height and width occupied by the set of multicolor light-emitting elements of the adjacent multicolor pixels. The multi-color light-emitting element and the white light-emitting element are each surface-mounted on the microarray substrate. The white light-emitting substrate has the white light-emitting element directly bonded to the white light-emitting substrate, and is also directly bonded to the microarray substrate. The microarray substrate is configured such that each of the multicolor light-emitting elements is directly bonded to it, and that multiple microarrays are mounted on a tile substrate as an array. Light-emitting components packaged as surface-mount components.

2. Each of the multiple rows and multiple columns of the microarray in the surface mount component alternately includes the white light-emitting pixels and the multicolor pixels in the microarray of the surface mount component. The light-emitting component according to claim 1.

3. The microarray substrate is configured to be mounted on a tile substrate as an array of multiple microarrays. The light-emitting component according to claim 1 or 2.

4. The white light-emitting device comprises a white LED, The aforementioned multi-color light-emitting device comprises a set of red LEDs, green LEDs, and blue LEDs. The light-emitting component according to any one of claims 1 to 3.

5. The sum of the height and width occupied by the set of multicolor light-emitting elements for each multicolor pixel is approximately 1% to 20% of the height and width of the adjacent white pixel, and the height and width of each white pixel is approximately 1% to 20% of the sum of the height and width occupied by the adjacent multicolor pixels. The light-emitting component according to any one of claims 1 to 4.

6. The sum of the height and width occupied by the set of multicolor light-emitting elements for each multicolor pixel is approximately 5% to 10% of the height and width of the adjacent white pixel, and the height and width of each white pixel is approximately 5% to 10% of the sum of the height and width occupied by the adjacent multicolor pixels. The light-emitting component according to claim 5.

7. The light-emitting component is configured as one of the following: a BGA package, a QFN package, or a PLCC package. The light-emitting component according to any one of claims 1 to 6.

8. The light-emitting component is 5 mm x 5 mm or smaller. The light-emitting component according to any one of claims 1 to 7.

9. The system further comprises a light-transmitting encapsulation layer covering multiple light-emitting elements or multiple LEDs. The light-emitting component according to any one of claims 1 to 8.

10. The array comprises an array of light-emitting components according to any one of claims 1 to 9, mounted on a tile substrate, In the microarray located at the edge of the tile substrate, the spacing to the edge of the tile substrate is half the spacing between adjacent microarrays within the tile substrate, so as to provide a visually continuous appearance when multiple tiles are adjacent. Luminous tiles.

11. The invention comprises an array of multiple light-emitting tiles as described in claim 10, The tiles are arranged adjacently such that the spacing between adjacent tile microarrays is the same as the spacing between adjacent microarrays of the same tile, providing a visually continuous appearance across the boundaries of adjacent tiles. Video display wall.

12. Each of these constitutes multiple multicolor pixels, each containing multiple light-emitting elements of different colors and having an overall height and width. The aforementioned multi-color pixels are surface-mounted on a microarray substrate, Each comprises a plurality of white pixels, each including a white light-emitting element having an overall height and width at least substantially equal to the sum of the height and width occupied by one set of multicolor light-emitting elements in each of the multicolor pixels, The white pixels are surface-mounted on the microarray substrate adjacent to the multicolor pixels, forming a microarray in which the multicolor pixels and the white pixels alternate. Equipped with, Surface mounting the white light-emitting element includes first surface mounting the white light-emitting element onto individual substrates, and then surface mounting each of the individual substrates having the white light-emitting element onto the microarray substrate. Method for manufacturing luminescent microarrays.

13. The method further comprises surface mounting the light-emitting elements of different colors and the white light-emitting element onto the microarray substrate, followed by sealing the light-emitting elements of different colors and the white light-emitting element with a light-transmitting protective layer. The method for manufacturing a light-emitting microarray according to claim 12.

14. The light-emitting elements of different colors and the white light-emitting element are configured such that the resulting light-emitting surface-mount component includes the microarray with dimensions of 5 mm x 5 mm or less. A method for manufacturing a light-emitting microarray according to claim 12 or 13.

15. The multicolor light-emitting body and the white light-emitting body each comprise at least one of a plurality of LEDs, a plurality of OLEDs, a plurality of PLEDs, a plurality of AMOLEDs, a plurality of LCDs, or a plurality of LECs. The light-emitting component according to any one of claims 1 to 4.

16. The light-emitting elements of different colors and the white light-emitting element each comprise at least one of a plurality of LEDs, a plurality of OLEDs, a plurality of PLEDs, a plurality of AMOLEDs, a plurality of LCDs, or a plurality of LECs. A method for manufacturing a light-emitting microarray according to any one of claims 12 to 14.

17. A microarray having at least four self-emissive pixels in an array of at least 2x2 having at least two horizontal pixels and at least two vertical pixels, Microarray substrate and White light-emitting substrate and Equipped with, At least two of the pixels are white light-emitting pixels, and at least two of the pixels are multicolor pixels that include a set of multicolor light-emitting elements. The white light-emitting pixel includes at least one white light-emitting element having a height and width that are at least substantially equal to the height and width of a pair of multicolor light-emitting elements that constitute the multicolor pixels of adjacent pixels. The microarray substrate is configured such that each of the multicolor light-emitting elements is directly bonded to it, and that it is mounted on a tile substrate as an array of multiple microarrays. The white light-emitting substrate has the white light-emitting element directly bonded to the white light-emitting substrate, and is also directly bonded to the microarray substrate. Light-emitting surface mount components.

Images