Laminated micro LED display with micro reflector and method of manufacturing

Abstract

The invention relates to a laminated micro LED display with micro reflectors and a method of manufacture. A method of manufacturing a micro-reflective surface disposed on or inside a window or mirror surface. A micro LED display for a vehicle window or windshield combines an array of micro LEDs with an aligned array of micro reflectors. A shaped micro-reflective surface is fabricated by laser etching a first glass sheet. The micro LED includes a side emitting LED. A shaped micro-reflective surface of the micro LED display emits collimated horizontal light for legal luminosity requirements of a parking lamp, a parking lamp installed at a central high position or a head-up display. In addition, lighting efficiency is improved by using micro LEDs coupled to micro reflectors. The micro LED display is unencapsulated, encapsulated in a clear coating, or laminated between two glass sheets to make a laminated light emitting window system. Laminated micro LED displays for use in windows of vehicles, including automobiles, trucks, motorcycles, farm equipment, ships, and airplanes.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to micro light emitting diode (micro-LED) displays with micro-reflectors for vehicle lighting applications. BACKGROUND

[0002] Micro-LEDs are tiny, individual light emitting diodes typically less than 100 microns in size that can be manufactured using advanced semiconductor manufacturing techniques. Micro-LED displays offer many advantages over the previous generation of LED display systems, such as higher brightness, improved color accuracy, higher energy efficiency, and other enhanced performance features. These attributes make micro-LED displays well-suited for automotive applications (e.g., in a flat panel communication system for a vehicle), where visibility, clarity, and power efficiency are highly desirable.

[0003] Automobiles and airplanes use a variety of displays to provide information to the driver or pilot (e.g., instrument gauges, computer monitor screens, warning lights) and to communicate information to other drivers (e.g., rear brake lights, turn signals, center mounted high stop lamp (CHSML)). Lighting systems typically have a housing and / or large optical system for tail lights, head lights, or CHSML that are often placed in the body of the vehicle. In this way, space is required to package the lighting module, which adds more weight and assembly process time. Head-up displays (HUDs) require projecting light onto a transparent surface (glass or plastic), which typically requires the use of a separate light projector. SUMMARY

[0004] A method of manufacturing a micro-reflective surface disposed on a surface of a window or mirror or disposed inside a window or mirror is disclosed. A micro light emitting diode (micro-LED) display for a vehicle window, mirror, or windshield combines an array of micro-LEDs with an aligned array of micro-reflectors. The shaped micro-reflective surface can be manufactured by laser etching a first glass sheet. The micro-LEDs can include side-emitting micro-LEDs. The shaped micro-reflective surface of the micro-LED display emits collimated horizontal light that can be used for any lighting requirements of a vehicle, including but not limited to the legal photometric requirements for stop lights, center high mounted stop lights (CHMSLs), head-up displays (HUDs), head lights, tail lights, side lights, side mirror lights, rear brake lights, truck cargo box lights, signal lights, and the like. Additionally, lighting efficiency can be improved by using micro-LEDs that are optically coupled to the micro-reflectors.

[0005] The micro-LED display can be (1) open (unencapsulated), (2) encapsulated with a transparent coating, or (3) they can be laminated between two glass sheets to make an integrated light-emitting window system. The micro-LED display can be used for side mirrors, rearview mirrors, brake lights, sunroofs / roof windows, windows, and windshields of different types of vehicles including, but not limited to, cars, trucks, bicycles, motorcycles, farm equipment, construction equipment, boats, trains, and airplanes, etc.

[0006] In a first example, a micro-LED display unit includes a substrate, a micro-LED disposed on the substrate, and a micro-reflector disposed on the substrate adjacent to the micro-LED. The micro-LED is a side-emitting micro-LED. The micro-reflector includes a reflective surface facing the micro-LED. The micro-reflector has a height (H) above an upper surface of the substrate that is less than or equal to about 50 microns. A distance (d) between the micro-LED and the micro-reflector is less than or equal to about 0.5 mm.

[0007] In another example, the reflective surface is a planar surface oriented at an angle (q) relative to a line normal to the substrate. The angle (q) can be in a range from about -30 degrees to about +30 degrees. Positive values of the angle (q) are measured in a clockwise direction.

[0008] In another example, the micro-reflector has a trapezoidal cross-sectional shape.

[0009] In another example, light emitted from the micro-LED display unit is emitted at an angle (q) relative to the substrate, where q is less than or equal to about 30 degrees.

[0010] In another example, the micro-LED display unit further includes a layer of transparent material covering and conformally encapsulating the micro-LED, the micro-reflector, and an upper surface of the substrate.

[0011] In another example, the substrate of the micro-LED display is transparent.

[0012] In another example, the upper surface of the substrate is reflective.

[0013] In another example, the micro-reflector and the substrate are integrally made of a single material in an integrated manner.

[0014] In another example, the substrate is curved.

[0015] In another example, a laminated micro light emitting diode (micro-LED) display includes a substrate having a front side, a back side, and an array of micro-LEDs disposed on the front side of the substrate; a first sheet of transparent material having a first front side and a first back side; and an array of recessed volumes disposed on the first back side of the first sheet. Each recessed volume includes one or more interior surfaces that define a geometry of the recessed volume. A reflective coating is disposed on a rear portion of the one or more interior surfaces. A second sheet of transparent material is bonded and laminated to the substrate. Each micro-LED is aligned with and disposed inside a matching recessed volume.

[0016] In another example, each recessed volume has a triangular, semi-circular, or oval shape.

[0017] In another example, each recessed volume has a curved triangular shape with two curved sidewalls.

[0018] In another example, each recessed volume has a trapezoidal or inverted trapezoidal shape.

[0019] In another example, each recessed volume has an inverted parabolic shape.

[0020] In another example, each recessed volume has a concave reflective surface and a convex opposing surface.

[0021] In another example, the laminated micro-LED display is integrated into a window, windshield, or mirror of a vehicle, wherein the vehicle is selected from the group consisting of a car, a truck, a bicycle, a motorcycle, farm equipment, construction equipment, a boat, a train, and an airplane.

[0022] In another example, the laminated micro-LED display is integrated as a heads-up display (HUD) in a front windshield of a car.

[0023] In another example, the laminated micro-LED display is configured as a center high mount stop lamp (CHMSL) disposed in a rear windshield of a car.

[0024] In another example, a method of manufacturing a laminated micro light emitting diode (micro-LED) display includes: (a) providing a first sheet of a first transparent material having a first front side and a first back side, (b) fabricating a plurality of recessed volumes into the first back side of the first sheet, wherein each respective one of the recessed volumes has one or more interior surfaces that define a cross-sectional shape of each respective one of the recessed volumes, (c) depositing a reflective coating onto a back portion of at least one of the one or more interior surfaces of each respective one of the recessed volumes, (d) providing a substrate having a second front side, a second back side, and a plurality of micro light emitting diodes (micro-LEDs) disposed on the second front side of the substrate, (e) aligning the plurality of micro-LEDs with the plurality of recessed volumes, wherein each respective one of the plurality of recessed volumes has a respective one of the plurality of micro-LEDs, (f) bonding the second front side of the substrate to the first back side of the first sheet, thereby encapsulating each respective one of the plurality of micro-LEDs inside each respective one of the plurality of recessed volumes, (g) providing a second sheet of a second transparent material; and (h) adhesively bonding and laminating the second sheet to the second back side of the substrate.

[0025] In another example, the reflective back portion of at least one of the one or more interior surfaces has less than or equal to about 50% of a total surface area of each respective one of the plurality of recessed volumes.

[0026] The present invention provides the following technical solutions.

[0027] Technical Solution 1. A micro light emitting diode (micro-LED) display unit, comprising:

[0028] a substrate;

[0029] a micro-LED disposed on the substrate; and

[0030] a micro-reflector disposed on the substrate adjacent to the micro-LED;

[0031] wherein the micro-reflector includes a reflective surface facing the micro-LED;

[0032] wherein the micro-LED is a side-emitting micro-LED;

[0033] wherein the micro-reflector has a height (H) above an upper surface of the substrate that is less than or equal to about 50 microns; and

[0034] wherein a distance (d) between the micro-LED and the micro-reflector is less than or equal to about 0.5 mm.

[0035] TECHNICAL SOLUTION 2. The micro-LED display unit of TECHNICAL SOLUTION 1,

[0036] wherein the reflective surface is a planar surface oriented at an angle (q) relative to a line normal to the substrate;

[0037] wherein the angle (q) is in a range from about -30 degrees to about +30 degrees; and

[0038] wherein the positive value of the angle (q) is measured in a clockwise direction.

[0039] TECHNICAL SOLUTION 3. The micro-LED display unit of TECHNICAL SOLUTION 1, wherein the micro-reflector has a trapezoidal cross-sectional shape.

[0040] TECHNICAL SOLUTION 4. The micro-LED display unit of TECHNICAL SOLUTION 1, wherein light emitted from the micro-LED display unit is emitted in a collimated manner at an angle (q) relative to the substrate, wherein q is less than or equal to about 30 degrees.

[0041] TECHNICAL SOLUTION 5. The micro-LED display unit of TECHNICAL SOLUTION 1, further comprising a layer of transparent material covering and conformally encapsulating the micro-LEDs, the micro-reflectors, and the upper surface of the substrate.

[0042] TECHNICAL SOLUTION 6. The micro-LED display unit of TECHNICAL SOLUTION 1, wherein the substrate is transparent.

[0043] TECHNICAL SOLUTION 7. The micro-LED display unit of TECHNICAL SOLUTION 1, wherein the upper surface of the substrate is reflective.

[0044] TECHNICAL SOLUTION 8. The micro-LED display unit of TECHNICAL SOLUTION 1, wherein the micro-reflectors and the substrate are integrally made of a single material.

[0045] TECHNICAL SOLUTION 9. The micro-LED display unit of TECHNICAL SOLUTION 1, wherein the substrate is curved.

[0046] TECHNICAL SOLUTION 10. A laminated micro light emitting diode (micro-LED) display, comprising:

[0047] a substrate comprising a front side, a back side, and a plurality of micro-LEDs disposed on the front side of the substrate;

[0048] a first sheet of a first transparent material comprising a first front side, a first back side, and a plurality of recessed volumes;

[0049] a reflective coating disposed on a back portion of each respective recessed volume of the plurality of recessed volumes; and

[0050] a second sheet of a second transparent material bonded and laminated to the backside of the substrate; and

[0051] wherein each recessed volume includes a respective one of the plurality of micro-LEDs.

[0052] Technical solution 11. The laminated micro-LED display of technical solution 10, wherein each respective one of the recessed volumes has a triangular, semi-circular, or oval cross-sectional shape.

[0053] Technical solution 12. The laminated micro-LED display of technical solution 10, wherein each respective one of the recessed volumes has a curved triangular cross-sectional shape having two curved sidewalls.

[0054] Technical solution 13. The laminated micro-LED display of technical solution 10, wherein each respective one of the recessed volumes has a trapezoidal or inverted trapezoidal cross-sectional shape.

[0055] Technical solution 14. The laminated micro-LED display of technical solution 10, wherein each respective one of the recessed volumes has an inverted parabolic cross-sectional shape.

[0056] Technical solution 15. The laminated micro-LED display of technical solution 10, wherein each respective one of the recessed volumes has a concave reflective surface and a convex opposing surface.

[0057] Technical solution 16. The laminated micro-LED display of technical solution 10, wherein the laminated micro-LED display is integrated into a window, windshield, and / or mirror of a vehicle, wherein the vehicle is selected from the group consisting of an automobile, a truck, a bicycle, a motorcycle, farm equipment, construction equipment, a boat, a train, and an airplane.

[0058] Technical solution 17. The laminated micro-LED display of technical solution 16, wherein the laminated micro-LED display is integrated as a heads-up display (HUD) in a front windshield of an automobile.

[0059] Technical solution 18. The laminated micro-LED display of technical solution 16, configured as a center high mounted stop lamp (CHMSL) disposed in a rear windshield of an automobile.

[0060] Technical solution 19. A method of manufacturing a laminated micro light emitting diode (micro-LED) display, comprising:

[0061] (a) providing a first sheet of a first transparent material having a first front side and a first back side;

[0062] (b) fabricating a plurality of recessed volumes into the first back side of the first sheet, wherein each respective recessed volume of the plurality of recessed volumes includes one or more interior surfaces that define a cross-sectional shape of each respective recessed volume of the plurality of recessed volumes;

[0063] (c) depositing a reflective coating onto a reflective back portion of at least one of the one or more interior surfaces of each respective recessed volume of the plurality of recessed volumes;

[0064] (d) providing a substrate having a second front side, a second back side, and a plurality of micro light emitting diodes (micro-LEDs) disposed on the second front side of the substrate;

[0065] (e) aligning the plurality of micro-LEDs with the plurality of recessed volumes, wherein each respective recessed volume of the plurality of recessed volumes includes a respective one of the plurality of micro-LEDs;

[0066] (f) bonding the second front side of the substrate to the first back side of the first sheet, thereby encapsulating each respective micro-LED of the plurality of micro-LEDs inside each respective recessed volume of the plurality of recessed volumes;

[0067] (g) providing a second sheet of a second transparent material; and

[0068] (h) adhesively bonding and laminating the second sheet to the second back side of the substrate.

[0069] Technical Solution 20. The method of Technical Solution 19, wherein the reflective back portion of at least one of the one or more interior surfaces comprises less than or equal to about 50% of a total surface area of each respective recessed volume of the plurality of recessed volumes. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1A A schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro light emitting diode (micro-LED) display unit according to the present disclosure is shown.

[0071] Figure 1B A schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro-LED display unit according to the present disclosure is shown. Figure 1A A schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro-LED display unit according to the present disclosure is shown.

[0072] Figure 2 A schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro-LED display unit according to the present disclosure is shown.

[0073] Figure 3 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display unit according to the present disclosure.

[0074] Figure 4 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0075] Figure 5 A schematic cross-sectional elevation view showing an example of an open (unpackaged) micro-LED display unit according to the present disclosure.

[0076] Figure 6 A schematic cross-sectional elevation view showing an example of an open (unpackaged) micro-LED display according to the present disclosure.

[0077] Figure 7A A schematic cross-sectional elevation view showing an example of a first process step for manufacturing a packaged micro-LED display according to the present disclosure.

[0078] Figure 7B A schematic cross-sectional elevation view showing an example of a second process step for manufacturing a packaged micro-LED display according to the present disclosure.

[0079] Figure 7C A schematic cross-sectional elevation view showing an example of a third process step for manufacturing a packaged micro-LED display according to the present disclosure.

[0080] Figure 7D A schematic cross-sectional elevation view showing an example of a fourth process step for manufacturing a packaged micro-LED display according to the present disclosure.

[0081] Figure 7E A schematic cross-sectional elevation view showing an example of a fifth process step for manufacturing a packaged micro-LED display according to the present disclosure.

[0082] Figure 7F A schematic cross-sectional elevation view showing an example of a sixth process step for manufacturing a packaged micro-LED display according to the present disclosure.

[0083] Figure 8A A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0084] Figure 8B A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0085] Figure 8CA schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0086] Figure 8D A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0087] Figure 8E A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0088] Figure 8F A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0089] Figure 8G A schematic cross-sectional elevation view showing an example of a packaged micro-LED display according to the present disclosure.

[0090] Figure 9 A schematic elevation view showing an example of a car with a pair of micro-LED displays according to the present disclosure.

[0091] Figure 10 A schematic process flow diagram showing an example of a process illustrating steps for manufacturing a micro-LED display according to the present disclosure.

[0092] Figure 11 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display unit according to the present disclosure.

[0093] Figure 12 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display unit according to the present disclosure.

[0094] Figure 13 A schematic cross-sectional elevation view showing an example of an open (unpacked) micro-LED display unit according to the present disclosure.

[0095] Figure 14 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display unit according to the present disclosure. DETAILED DESCRIPTION

[0096] A method for manufacturing a shaped micro-reflective surface disposed on the surface of a transparent window or windshield or disposed inside a transparent window or windshield is disclosed. A micro light emitting diode (micro-LED) display for a vehicle window combines an array of micro-LEDs with an aligned array of micro-reflectors. The shaped micro-reflective surface can be manufactured by using a laser etching technique. The array of shaped micro-reflective surfaces in the micro-LED display creates an optimized collimated beam pattern for the legal photometric requirements of a stop lamp or center high mounted stop lamp (CHMSL). Additionally, lighting efficiency can be improved by using the array of micro-LEDs and micro- reflector structures. The micro-LED display can be positioned and incorporated between a pair of laminated transparent sheets, which can be glass or plastic, to manufacture an integrated light-emitting laminated window or windshield system.

[0097] The term "window" broadly includes windows, mirrors, and windshields. The light-emitting window, which can be a heads-up display (HUD), can be part of an automobile, motorcycle, boat, airplane, or jet. The micro-LED display disclosed herein can be used in side mirrors, rear window mirrors, sunroofs / tops in automobiles, trucks, farm equipment, motorcycles, construction equipment, etc. In the drawings, the reflective surface is illustrated as a thick black line. The word "open" means "unencapsulated" in this document. The phrases "side-emitting" and "side-fire" are interchangeable as they refer to LEDs or micro-LEDs. The phrases "micro- reflector" and "micro-reflective structure" are interchangeable. When the term "shallow" refers to some examples of the angle q, it means that q is less than or equal to about 30 degrees. The term "about" means + / - 5% of the reference value. The phrase "unidirectional, side-emitting micro-LED" means that light is emitted from a single side of the micro-LED.

[0098] The reflective surface on the micro-reflectors can include a polished surface and / or one or more coatings of deposited reflective material and / or a dielectric stack including, for example, silver, gold, copper, silicon dioxide (Si02), silicon nitride (Si3N4), polyimide, benzocyclobutene (BCB), spin-on glass (SOG), aluminum oxide (AI2O3), hafnium oxide (Hf02), and / or combinations thereof. Photolithography and masking can be combined with physical or chemical vapor deposition, sputter coating, etc., to selectively deposit the reflective coating on selected surfaces but not elsewhere. Alternatively, the reflective coating can be initially applied to the entire surface and then selectively removed from the unwanted (non-reflective) surfaces using laser etching or a similar removal process.

[0099] Figure 1AA schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro-LED display unit 8 according to the present disclosure is shown. The micro-LED display unit 8 includes a substrate 10 having a micro-reflector 12 disposed on a front side of the substrate 10, and a micro light emitting diode (micro-LED) 14 also disposed on the front side of the substrate 10, positioned next to and adjacent to the micro-reflector 12. In some embodiments, the upper surface 11 of the substrate 10 can be reflective or non-reflective (as shown in this example). The micro-reflector 12, which has a trapezoidal shape in this example, has at least one angled reflective front face 23 having a reflective surface 16 angled back (i.e., counterclockwise) at an angle (q) (see Figure 1B ). The reflective front face 16 faces the micro-LED 14. The opposing back face 13 of the micro-reflector 12 can be reflective or non-reflective (as shown in this example). The upper (topmost) surface 25 of the micro-reflector 12 can not be coated with a reflective coating. The substrate 10 can be made of glass, plastic, polymer, polysilicon, silicon carbide, silicon nitride, aluminum oxide, zirconium oxide, sapphire, a semiconductor, a dielectric, or an electrically insulating material. The substrate 10 can be flat or curved. The substrate 10 can be transparent, translucent, or opaque. The micro-reflector 12 can be made of glass or a polymeric material such as polycarbonate (PC) or polymethyl methacrylate (PMMA). The micro-reflector 12 and the substrate 10 can be integrally made of a single material in an integrated manner.

[0100] Still referring to Figure 1A , the micro-LED 14 is disposed on the substrate 10 at a distance (d) from the reflective surface 16 of the micro-reflector 12. In some embodiments, d is less than or equal to about 0.05 mm. In some embodiments, d is less than or equal to about 0.1 mm. In some embodiments, d is less than or equal to about 0.5 mm. The micro-reflector 12 has a height (H) above the upper surface 11 of the substrate 8. In some embodiments, H is less than or equal to about 20 microns. In some embodiments, H is less than or equal to about 30 microns. In some embodiments, H is less than or equal to about 40 microns. In some embodiments, H is less than or equal to about 50 microns.

[0101] Still referring to Figure 1Aindicating a forward direction 4 and a rearward direction 6 of the micro-LED display 8. The reflective front face 16 is located on a forward-facing side surface 23 of the micro-reflector 12 (i.e., facing the forward direction 4). The micro-LED 14 can be a side-emitting LED that emits rearward light rays 15 in a lateral (e.g., horizontal) direction in the rearward direction 6, with only a small amount (or no) light being emitted vertically. Alternatively, the micro-LED 14 can be a unidirectional side-emitting micro-LED that emits light primarily as rearward light rays 15 in the rearward direction 6. The rearward light rays 15 reflect off the reflective surface 16 and then project as forward light rays 17 at an angle q relative to the upper surface 11 of the substrate 10 primarily in the forward direction 4. Due to the unique geometry of the optical element and the light-emitting element in Figure 1A the forward direction 4 as a collimated narrow beam of light having a vertical thickness of approximately H with a relatively narrow angular dispersion. Due to its unique optical configuration, very little light is emitted vertically from the micro-LED display unit 8. The intensity of light emitted by the micro-LED display unit 8 can be less than or equal to approximately 1000 lumens.

[0102] Figure 1B a schematic cross-sectional elevation view of an example of an open (unencapsulated) micro-LED display unit 8 according to the present disclosure is shown. Figure 1A In some embodiments, q is less than or equal to approximately 30 degrees. In other embodiments, q is less than or equal to approximately 25 degrees. In other embodiments, q is less than or equal to approximately 20 degrees. In other embodiments, q is less than or equal to approximately 15 degrees. In other embodiments, q is less than or equal to approximately 10 degrees. In other embodiments, q is less than or equal to approximately 5 degrees. The opposing rear face 13 can be inclined at the same angle q as the front reflective face 16. Alternatively, the opposing rear face 13 can be inclined at a different angle than the front reflective face 23, e.g., perpendicular to the substrate 10.

[0103] Figure 2 a schematic cross-sectional elevation view of an example of an open (unencapsulated) micro-LED display 3 according to the present disclosure is shown. The open micro-LED display 3 includes an array of micro-reflectors 12, 12', 12", etc. disposed on a substrate 10, and an aligned array of micro-LEDs 14, 14', 14", etc. are also disposed on the substrate 10. The array of micro-LEDs 14, 14', 14" are aligned and positioned between adjacent micro-reflectors 12, 12', 12", etc. Forward-projecting light rays 17, 17', 17", etc. emit light in the primarily forward direction 4 at a shallow angle q (see Figure 1B). The array of micro-LEDs 14, 14', 14", etc. and the array of micro-reflectors 12, 12', 12", etc. can be positioned on a square, rectangular, or circular grid (not shown) when viewed from above the substrate 10. While only three micro-LED display units are shown for ease of illustration and discussion, it will be appreciated that the micro-LED display 3 can include any number of individual micro-LED display units (as Figure 1A illustrated in FIG. 1).

[0104] Figure 3 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display unit 9 according to the present disclosure is shown. The packaged micro-LED display unit 9 includes a substrate 10 having a transparent cap 18 bonded to the front side of the substrate 10. A micro light emitting diode (micro-LED) 14 is also disposed on the front side of the substrate 10. The transparent cap 18 has a recessed volume (pocket) 20 which has a trapezoidal shape in this example. The micro-LED 14 is positioned beneath the transparent cap 18 and the transparent cap 18 encapsulates and surrounds the micro-LED 14. The sloped inner back face 21 is reflective and angled clockwise at a shallow angle (q). The opposing sloped inner front face 19 of the transparent cap 18 is non-reflective. The transparent cap 18 can be made of any transparent material including glass, plastic, polymer, polycarbonate (PC) material, acrylic material such as polymethyl methacrylate (PMMA), thermoplastic such as thermoplastic polyurethane (TPU), glass-ceramic material such as soda-lime-silica glass-ceramic, alumino-silicate glass-ceramic, lithium-alumino-silicate glass-ceramic, spinel glass-ceramic, and beta-quartz glass-ceramic, sapphire, and / or combinations thereof. The substrate 10 can be made of glass, plastic, polymer, electrically insulating material, polycarbonate (PC) material, acrylic material such as polymethyl methacrylate (PMMA), thermoplastic such as thermoplastic polyurethane (TPU), glass-ceramic material such as soda-lime-silica glass-ceramic, alumino-silicate glass-ceramic, lithium-alumino-silicate glass-ceramic, spinel glass-ceramic, and beta-quartz glass-ceramic, sapphire, and / or combinations thereof. The transparent cap 18 and / or the substrate 10 can be flat or curved. The substrate 10 can be transparent, translucent, or opaque. The upper surface 11 of the substrate 10 can be reflective or non-reflective.

[0105] Still referring to Figure 3, the forward direction 4 and the rearward direction 6 of the packaged micro-LED display unit 9 are illustrated. The reflective rear inner face 21 is located on the forward-facing back side 21 of the transparent cap 18 (i.e., facing the forward direction 4). The micro-LEDs 14 can be directional side-emitting micro-LEDs that emit rearward light rays 15 in a lateral (horizontal) direction in the rearward direction 6 with a small amount (or no) light rays emitted vertically or in the forward direction 4. The rearward light rays 15 reflect off the reflective surface 21 and then project as forward light rays 17 at a shallow angle q relative to the upper surface 11 of the substrate 10 primarily in the forward direction 4. Due to this geometric arrangement of the optical elements, the majority of the forward light rays 17, 17', etc. are emitted in the forward direction 4 as a collimated beam having a vertical thickness of about H and a relatively narrow angular spread. Due to this unique optical configuration, very little light is emitted vertically from the packaged micro-LED display unit 9. The intensity of the light emitted by the packaged micro-LED display unit 9 can be less than or equal to about 1000 lumens.

[0106] Still referring to Figure 3 In some embodiments, q is less than or equal to about 30 degrees. In other embodiments, q is less than or equal to about 25 degrees. In other embodiments, q is less than or equal to about 20 degrees. In other embodiments, q is less than or equal to about 15 degrees. In other embodiments, q is less than or equal to about 10 degrees. In other embodiments, q is less than or equal to about 5 degrees.

[0107] Figure 4 A schematic cross-sectional elevation view showing an example of a packaged micro-LED display 2 according to the present disclosure is shown. The packaged micro-LED display 2 includes an upper transparent first sheet 18 having an array of trapezoidal recessed volumes 20, 20', 20", etc. and an array of multiple micro-reflective faces 21, 21', 21", etc. disposed on a forward-facing rear surface 21, 21', 21", etc. of each respective recessed volume 20, 20', 20", etc. An array of multiple micro-LEDs 14, 14', 14", etc. is also disposed on a substrate 10. The array of micro-LEDs 14, 14', 14" is aligned and positioned inside each respective recessed volume of the array of recessed volumes 20, 20', 20", etc. In other words, each individual micro-LED 14 is enclosed within a matching recessed volume 20. The transparent cap 18 is bonded to the substrate 10.

[0108] Still referring to Figure 4 The forward-projecting light rays 17, 17', 17", etc. emit light in the primarily forward direction 4 at an angle (q) relative to a line oriented perpendicular to the substrate 10. See Figure 1BWhen viewed from above the substrate 10, the array of micro-LEDs 14 and the array of micro-reflectors 21 can be positioned and arranged on a square, rectangular or circular grid (not shown). The recessed volumes 20, 20', 20", etc. can be manufactured by laser etching the first sheet 18. The first sheet 18 with the bonded substrate 10 is then laminated and bonded to a second sheet 24 (which can be transparent or opaque) with an adhesive 22. The adhesive 22 can include polyvinyl butyral (PVB) or equivalent adhesive. The two laminated sheets 18 and 24 can be bagged, heated and compressed together in an autoclave under pressure and high temperature.

[0109] Figure 5 A schematic cross-sectional elevation view of an example of an open (unencapsulated) micro-LED display unit 1 according to the present disclosure is shown. The micro-LED display unit 1 includes a substrate 10 having a micro-reflector 12 disposed on a front side of the substrate 10, and a micro light emitting diode (micro-LED) 14 also disposed on the front side of the substrate 10, positioned in close proximity to the micro-reflector 26. The micro-reflector 26 can be bonded to the substrate 10 with an adhesive 30 such as polyvinyl butyral (PVB). The upper surface 11 of the substrate 10 can be reflective or non-reflective. The micro-reflector 26, which has an inverted trapezoidal shape, has at least one sloped reflective front face 28 angled clockwise at an angle q. The opposing sloped back face 32 of the micro-reflector 26 can be reflective (as shown in this example) or non-reflective. The substrate 10 can be made of glass, plastic, polymer or electrically insulating material. The substrate 10 can be flat or curved, and it can be transparent, translucent or opaque. The substrate 10 can be angled at different angles (a), where a can be selected by matching it to the slope of the rear window in a car (see Figure 9 ). In some embodiments, q can be approximately equal to a. In other embodiments, q < a. In some embodiments, q is selected so that the direction of the forward light ray 17 is approximately horizontal with respect to the ground (e.g., for a center high mount stop lamp (CHMSL) application or for a head-up display (HUD) application). See, e.g., Figure 9 .

[0110] Figure 6A schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro-LED display 5 according to the present disclosure is shown. The open micro-LED display 5 includes an array of multiple micro-reflector 34, 34', 34", etc. disposed on a substrate 10. An aligned array of multiple micro-LEDs 14, 14', 14", etc. is also disposed on the substrate 10. The array of micro-LEDs 14, 14', 14", etc. is aligned and positioned between adjacent micro-reflectors 34, 34', 34", etc. In this example, the micro-reflectors 34, 34', 34", etc. can be square (cuboid) with reflective faces 36, 36', and 36", etc. respectively that are perpendicular to the substrate 10 (i.e., q = 0 degrees). Forward-projected light rays 17, 17', 17", etc. emit light in a primarily horizontal forward direction. When viewed from above the substrate 10, the array of micro-LEDs 14, 14', 14", etc. and the array of micro-reflectors 34, 34', 34", etc. can be positioned on a square, rectangular, or circular grid (not shown).

[0111] Figure 7A A schematic cross-sectional elevation view showing an example of a first process step for fabricating an encapsulated micro-LED display 2 according to the present disclosure is shown. The first step includes providing a first sheet of transparent material 18 (which includes an upper front side and a lower back side) and then fabricating a plurality of identical recessed volumes 20, 20', 20", 20"' etc. by selectively laser etching or chemically removing material from the back side of the first sheet 18. Each recessed volume 20, 20', 20", 20"' etc. includes one or more interior surfaces (not numbered) that define the interior shape of each recessed volume. In this example, each recessed volume 20, 20', 20", 20"' etc. has a trapezoidal shape.

[0112] Figure 7B A schematic cross-sectional elevation view showing an example of a second process step for fabricating an encapsulated micro-LED display 2 according to the present disclosure is shown. The second step includes depositing a reflective coating 21, 21', 21", 21"' etc. onto the back portion of the interior surfaces of each recessed volume 20, 20', 20", 20"' etc.

[0113] Figure 7C A schematic cross-sectional elevation view showing an example of a third process step for fabricating an encapsulated micro-LED display 2 according to the present disclosure is shown. The third step includes providing a substrate 10 that includes a plurality of micro-LEDs 14, 14', 14", 14"' etc. disposed in an array on the front side of the substrate 10, where the substrate 10 has a back side.

[0114] Figure 7DA schematic cross-sectional elevation view showing an example of a fourth process step for fabricating a packaged micro-LED display 2 according to the present disclosure is shown. The fourth step includes aligning the micro-LEDs 14, 14', 14", 14"' and the like to the recessed volumes 20, 20', 20", 20"' and the like of the first sheet 18 and bonding the substrate 10 to the backside of the first sheet 18, thereby packaging the micro-LEDs 14, 14', 14", 14"' and the like in the recessed volumes 20, 20', 20", 20"' and the like of the transparent first sheet 18.

[0115] Figure 7E A schematic cross-sectional elevation view showing an example of a fifth process step for fabricating a packaged micro-LED display 2 according to the present disclosure is shown. The fifth step includes applying an adhesive layer 22 to the backside of the substrate 10. The adhesive 22 can include polyvinyl butyral (PVB) or equivalent adhesive.

[0116] Figure 7F A schematic cross-sectional elevation view showing an example of a sixth process step for fabricating a packaged micro-LED display 2 according to the present disclosure is shown. The sixth step includes adhesively bonding the second sheet 24 to both the backside of the substrate 10 and the first sheet 18. This final sixth step includes vacuum bagging the assembled sheets and autoclaving the bagged assembly under external pressure in a heated pressure vessel. This completes the packaging, bonding and lamination process.

[0117] Figure 8A A schematic cross-sectional elevation view showing an example of a packaged micro-LED display 80 according to the present disclosure is shown. An array of micro-LEDs 14, 14' and the like are packaged within triangular recessed volumes 40, 40' and the like of a first transparent sheet 18, respectively. Reflective surfaces 42, 42' and the like are disposed on back inner surfaces 41, 41' and the like of the recessed volumes 40, 40' and the like, respectively. The reflective surfaces 42, 42' and the like cover about 50% of the inner surface area of each recessed volume 40, 40' and the like, respectively.

[0118] Figure 8B A schematic cross-sectional elevation view showing an example of a packaged micro-LED display 82 according to the present disclosure is shown. An array of micro-LEDs 14, 14' and the like are packaged within semicircular recessed volumes 44, 44' and the like of a first transparent sheet 18, respectively. Reflective surfaces 46, 46' and the like are disposed on back inner surfaces 45, 45' and the like of the recessed volumes 44, 44' and the like, respectively. The reflective surfaces 46, 46' and the like cover about 50% of the inner surface area of each recessed volume 40, 40' and the like, respectively.

[0119] Figure 8CA schematic cross-sectional elevation view of an example of a packaged micro-LED display 84 according to the present disclosure is shown. An array of micro-LEDs 14, 14', etc. are respectively packaged within ovoid recessed volumes 48, 48', etc. of a first transparent sheet 18. Reflective surfaces 50, 50', etc. are respectively disposed on back inner surfaces 49, 49', etc. of the recessed volumes 48, 48', etc. The reflective surfaces 50, 50', etc. respectively cover about 50% of the inner surface area of each recessed volume 48, 48', etc.

[0120] Figure 8D A schematic cross-sectional elevation view of an example of a packaged micro-LED display 86 according to the present disclosure is shown. An array of micro-LEDs 14, 14', etc. are respectively packaged within curved triangular recessed volumes 52, 52', etc. of a first transparent sheet 18. Reflective surfaces 54, 54', etc. are respectively disposed on back inner surfaces 53, 53', etc. of the recessed volumes 52, 52', etc. The reflective surfaces 54, 54', etc. respectively cover about 50% of the inner surface area of each recessed volume 52, 52', etc.

[0121] Figure 8E A schematic cross-sectional elevation view of an example of a packaged micro-LED display 88 according to the present disclosure is shown. An array of micro-LEDs 14, 14', etc. are respectively packaged within asymmetrically concave-convex recessed volumes 56, 56', etc. of a first transparent sheet 18. Reflective surfaces 58, 58', etc. are respectively disposed on back inner surfaces 57, 57', etc. of the recessed volumes 56, 56', etc. The reflective surfaces 58, 58', etc. respectively cover about 50% of the inner surface area of each recessed volume 56, 56', etc.

[0122] Figure 8F A schematic cross-sectional elevation view of an example of a packaged micro-LED display 90 according to the present disclosure is shown. An array of micro-LEDs 14, 14', etc. are respectively packaged within inverted-trapezoidal recessed volumes 60, 60', etc. of a first transparent sheet 18. Reflective surfaces 62, 62', etc. are respectively disposed on back inner surfaces 61, 61', etc. of the recessed volumes 60, 60', etc. The reflective surfaces 62, 62', etc. respectively cover about 50% of the inner surface area of each recessed volume 60, 60', etc.

[0123] Figure 8G A schematic cross-sectional elevation view of an example of a packaged micro-LED display 92 according to the present disclosure is shown. An array of micro-LEDs 14, 14', etc. are respectively packaged within inverted-parabolic recessed volumes 64, 64', etc. of a first transparent sheet 18. Reflective surfaces 66, 66', etc. are respectively disposed on back inner surfaces 65, 65', etc. of the recessed volumes 64, 64', etc. The reflective surfaces 66, 66', etc. respectively cover about 50% of the inner surface area of each recessed volume 64, 64', etc.

[0124] Figure 9 A schematic elevation view showing an example of a car 68 having a pair of micro-LED displays 72 and 74 according to the present disclosure is shown. The front micro-LED display 72 is located on the inner side of the front windshield 70 of the car 68 and is used as a head-up display (HUD). Light rays 17 are emitted horizontally from the micro-LED display 72 towards the head (not shown) of the driver. The rear micro-LED display 74 is located on the inner side of the rear windshield 70 of the car 68 and is used as a center mounted high stop lamp (CMHSL). Light rays 17' are emitted horizontally from the micro-LED display 74 towards the head (not shown) of the driver following the car 68.

[0125] Figure 10 An example of a process flow diagram illustrating an example of process steps for manufacturing a micro-LED display according to the present disclosure is shown. Step 100 includes providing a first sheet of transparent material. Step 102 includes manufacturing (e.g., laser etching) a first array of recessed volumes into a back side of the first sheet. Step 104 includes depositing a reflective coating on a rear portion of an inner surface of each recessed volume. Step 106 includes providing a substrate including a second array of micro-LEDs disposed on a front side of the substrate. Step 108 includes aligning the second array of micro-LEDs with the first array of recessed volumes. Step 110 includes bonding the substrate to the back side of the first sheet, thereby encapsulating each micro-LED inside a matching recessed volume of the first sheet of transparent material. Step 112 includes providing a second sheet of a second transparent material. Step 114 includes adhesively bonding and laminating the second sheet to both the back side of the substrate and the back side of the first sheet.

[0126] Figure 11 A schematic cross-sectional elevation view showing an example of an encapsulated micro-LED display unit 9 according to the present disclosure is shown. This illustration is the same as that shown in FIG. 4, except that an opaque coating 94 has been applied to a rear upper portion of the upper surface 96 of the first sheet 18 (i.e., between points “A” and “B”) to prevent stray light from being emitted through the covered portion 94 of the first sheet 18. The remaining portion of the upper surface 96 of the first sheet 18 (i.e., between points “B” and “C”) is uncoated and can allow light to be transmitted through this portion of the first sheet 18. Figure 3

[0127] Figure 12 A schematic cross-sectional elevation view showing an example of an encapsulated micro-LED display unit according to the present disclosure is shown. In this embodiment, the transparent cap 18 can be adhesively bonded to the substrate 10 with an optically clear adhesive 98, which can include polyvinyl butyral (PVB).

[0128] Figure 13 ​A schematic cross-sectional elevation view showing an example of an open (unencapsulated) micro-LED display unit 8 according to the present disclosure is shown. In this example, the reflective surface 99 of the front face 23 of the micro-reflector 12 is curved in a concave fashion so as to best direct and guide the reflected light rays 17 in the forward direction 4 in a more controlled and precise manner. In this example, the back surface 13 is flat.

[0129] Figure 14 A schematic cross-sectional elevation view showing an example of an encapsulated micro-LED display 120 according to the present disclosure is shown. A first array of micro-reflectors 12, 12' and 12" (having reflective surfaces 16, 16' and 16", respectively) and a second aligned array of micro-LEDs 14, 14' and 14" are disposed on a substrate 10, which are conformally encapsulated in a transparent layer 122. The transparent layer 122 can initially comprise a polymeric material (e.g., an acrylic, a silicone, a polyurethane or a parylene) or a two-part epoxy resin composition (A+B; or A then B; or B then A) that is poured, sprayed, spin-coated, 3D-printed or otherwise chemically or physically deposited onto the substrate 10 conformally covering the second array of micro-LEDs 14, 14' and 14" and the first array of micro-reflectors 12, 12' and 12", respectively. The material, which is initially liquid, then hardens into a substantially smooth transparent coating 122. The thickness of the transparent coating 122 can be the same or about the same as the thickness of the substrate 10. In this example Figure 14 ) three micro-LEDs 14, 14', 14" and three micro-reflectors 12, 12', 12" are illustrated. However, in other embodiments, the micro-LED display 120 can have more than three micro-LEDs 14, 14', 14" and the like and more than three micro-reflectors 12, 12', 12" and the like.

[0130] In some embodiments, the micro-reflective structures can be made of the same material as the substrate in an integrated fashion, or they can be made of a different material that is bonded or deposited onto the substrate.

[0131] In some embodiments, the micro-reflective structures can be fabricated by using a laser etching or chemical removal process. Alternatively, the micro-reflector structures can be formed on the substrate by using a positive deposition process such as chemical or physical vapor deposition, 3D printing and / or electroplating.

[0132] In some embodiments, the laminated glass panel, window or windshield can include one or more additional anti-reflective layers, solar comfort layers, self-tinting layers and / or thin films and / or coatings that enhance the overall appearance.

[0133] In some embodiments, the reflective layer can have a thickness between about 5 nanometers and about 3 micrometers.

[0134] In some embodiments, one or more surfaces of the micro-LED can be coated with a reflective layer such that light is emitted only from the uncoated side or sidewalls of the micro-LED. In these embodiments, the uncoated sidewalls of the micro-LED that emit light unidirectionally can directly face the reflective sidewalls of the micro-reflector.

[0135] In some embodiments, the upper (topmost) surface of the micro-reflector is uncoated with a reflective coating.

[0136] In some embodiments, the reflective layer can be conformally deposited on the shaped and / or angled face(s) of the micro-reflector by using, for example, chemical vapor deposition (CVD), plasma-enhanced CVD (PECVD), ultra-high vacuum CVD (UHVCVD), rapid thermal CVD (RTCVD), metal-organic CVD (MOCVD), low-pressure CVD (LPCVD), limited reaction processing CVD (LRPCVD), atomic layer deposition (ALD), physical vapor deposition (PVD), chemical solution deposition, molecular beam epitaxy (MBE), and / or other similar processes combined with a wet or dry etching process, such as photolithography combined with a mask.

[0137] In some embodiments, the micro-LED can include a single LED element. In other embodiments, the micro-LED 14 can include multiple micro-LED elements, such as, for example, a red micro-LED element, a green micro-LED element, and / or a blue micro-LED element (not shown separately). The multi-color micro-LEDs can be formed from a range of suitable materials, such as, for example, semiconductor materials (e.g., silicon, gallium nitride, indium gallium nitride, etc.) and sapphire, depending on the desired emission color of the respective micro-LED. For example, gallium nitride (GaN) can be used for blue micro-LEDs, indium gallium nitride (InGaN) can be used for green micro-LEDs, and aluminum gallium indium phosphide (AlGaInP) can be used for red micro-LEDs.

[0138] In some embodiments, the laminated micro-LED display can be integrated into a window, windshield, or mirror of a vehicle, wherein the vehicle is selected from the group consisting of a car, a truck, a bicycle, a motorcycle, farm equipment, construction equipment, a boat, a train, and an airplane.

[0139] In some embodiments, the reflective back portion of at least one of the one or more inner surfaces of the recessed volume occupies less than or equal to about 50% of the total surface area of each recessed volume.

[0140] The detailed description and the accompanying drawings or diagrams are supportive and descriptive of the present teachings, but the scope of the present teachings is defined solely by the claims. While there have been described herein the best mode and other embodiments for the practice of the present teachings, various alternatives and modifications can be made to the teachings described and illustrated herein, and it is intended that the claims cover all such alternatives and modifications as come within the scope of the concepts disclosed and claimed herein.

Claims

1. A micro light emitting diode (micro-LED) display unit comprising: a substrate; a micro-LED disposed on the substrate; and a micro-reflector disposed on the substrate adjacent to the micro-LED; wherein the micro-reflector comprises a reflective surface facing the micro-LED; wherein the micro-LED is a side-emitting micro-LED; wherein the micro-reflector has a height (H) above an upper surface of the substrate that is less than or equal to about 50 microns; and wherein a distance (d) between the micro-LED and the micro-reflector is less than or equal to about 0.5 mm.

2. The micro-LED display unit of claim 1, the reflective surface is a planar surface oriented at an angle (q) relative to a line normal to the substrate; wherein, wherein the angle (q) is in a range from about -30 degrees to about +30 degrees; and wherein a positive value of the angle (q) is measured in a clockwise direction. the micro-reflector has a trapezoidal cross-sectional shape. 3.The micro-LED display unit of claim 1, wherein, light emitted from the micro-LED display unit is emitted in a collimated manner at an angle (q) relative to the substrate, where q is less than or equal to about 30 degrees. 4.The micro-LED display unit of claim 1, wherein, 5. The micro-LED display unit of claim 1, further comprising a layer of transparent material covering and conformally encapsulating the micro-LED, the micro-reflector, and an upper surface of the substrate. the substrate is transparent. 6.The micro-LED display unit of claim 1, wherein, an upper surface of the substrate is reflective. 7.The micro-LED display unit of claim 1, wherein, the micro-reflector and the substrate are integrally made of a single material in an integrated manner. 8.The micro-LED display unit of claim 1, wherein, 9. A laminated micro light emitting diode (micro-LED) display comprising: a substrate comprising a front side, a back side, and a plurality of micro-LEDs disposed on the front side of the substrate; a first sheet of a first transparent material comprising a first front side, a first back side, and a plurality of recessed volumes; a reflective coating disposed on a back portion of each respective recessed volume of the plurality of recessed volumes; and a second sheet of a second transparent material bonded and laminated to the back side of the substrate; and wherein each recessed volume comprises a respective one of the plurality of micro-LEDs.

10. A method of manufacturing a laminated micro light emitting diode (micro-LED) display comprising: (a) providing a first sheet of a first transparent material having a first front side and a first back side; (b) fabricating a plurality of recessed volumes into the first back side of the first sheet, wherein each respective recessed volume of the plurality of recessed volumes comprises one or more interior surfaces defining a cross-sectional shape of each respective recessed volume of the plurality of recessed volumes; (c) depositing a reflective coating onto a reflective back portion of at least one of the one or more interior surfaces of each respective recessed volume of the plurality of recessed volumes; (d) providing a substrate having a second front side, a second back side, and a plurality of micro light emitting diodes (micro-LEDs) disposed on the second front side of the substrate. ​ ​ ​ (e) aligning the plurality of micro-LEDs with the plurality of recessed volumes, wherein each respective recessed volume of the plurality of recessed volumes includes a respective one of the plurality of micro-LEDs; (f) bonding the second front side of the substrate to the first back side of the first sheet, thereby encapsulating each respective micro-LED of the plurality of micro-LEDs inside each respective recessed volume of the plurality of recessed volumes; (g) providing a second sheet of a second transparent material; and (h) adhesively bonding and laminating the second sheet to the second back side of the substrate.

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