Self-cleaning system for displays using micro-LEDs

Abstract

The present invention relates to a self-cleaning system for a display using micro-LEDs. A system includes a display. The display includes an array of LEDs covered by a transparent material. The array of LEDs includes first, second, third, and fourth LEDs respectively configured to emit red, green, blue, and violet light. The red, green, and blue light from the first, second, and third LEDs is visible to the human eye. The violet light from the fourth LED is not visible to the human eye. The system includes a photocatalytic coating disposed on the transparent material. The photocatalytic coating includes a photocatalyst that reacts to ultraviolet radiation present in sunlight and to the violet light emitted by the fourth LED in the array of LEDs. The system includes a controller configured to selectively turn on the fourth LED to activate the photocatalyst in the photocatalytic coating disposed on the transparent material.

Description

TECHNICAL FIELD

[0001] The information provided in this section is for the purpose of generally presenting the context of the disclosure. The work of the presently named inventors, to the extent the work is described in this section, as well as aspects of the description that can not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.

[0002] The present disclosure relates generally to display systems, and more particularly to a self-cleaning system for displays using micro-LEDs. BACKGROUND

[0003] Light emitting diode (LED)-based displays are used in a variety of applications. For example, LED-based displays are used in computers, mobile devices, televisions, kiosks, teller machines, home appliances, and vehicle instrument panels. Many of these LED-based displays include touch screens. As a result, fingerprints, oily residues, and other debris are often deposited on the surfaces of these displays. The surfaces of these displays need to be cleaned to eliminate fingerprints, oily residues, and other debris from the surfaces of these displays. SUMMARY

[0004] A system includes a display including an array of LEDs covered by a transparent material and including first, second, third, and fourth LEDs respectively configured to emit red, green, blue, and violet light. The red, green, and blue light from the first, second, and third LEDs is visible to the human eye. The violet light from the fourth LED is not visible to the human eye. The system includes a photocatalytic coating disposed on the transparent material. The photocatalytic coating includes a photocatalyst that reacts to ultraviolet radiation present in sunlight and to the violet light emitted by the fourth LED in the array of LEDs. The system includes a controller configured to selectively turn on the fourth LED to activate the photocatalyst in the photocatalytic coating disposed on the transparent material.

[0005] In another feature, the activation of the photocatalyst cleans an outer surface of the photocatalytic coating.

[0006] In another feature, the photocatalyst includes an oxide of a first metal and the oxide is doped with a second metal different from the first metal in the oxide. Alternatively, the photocatalyst includes an oxide of a metal and the oxide is doped with a non-metal.

[0007] In another feature, the controller is configured to turn on the fourth LED in response to an amount of sunlight surrounding the display being less than or equal to a predetermined threshold.

[0008] In another feature, the controller is configured to turn on the fourth LED in response to the presence of daylight around the display.

[0009] In another feature, a vehicle includes the system, and the controller is configured to turn on the fourth LED in response to the vehicle being started.

[0010] In another feature, a vehicle includes the system, and the controller is configured to turn on the fourth LED for a predetermined period of time in response to the vehicle being turned off, and to turn off the fourth LED after the predetermined period of time has elapsed.

[0011] In another feature, a vehicle includes the system, and the controller is configured to turn on the fourth LED in response to an amount of daylight around the display being less than or equal to a predetermined threshold.

[0012] In another feature, a vehicle includes the system, and the controller is configured to turn on the fourth LED in the presence of daylight around the display.

[0013] In another feature, the display further includes an anti-reflective coating disposed on the transparent material, and the photocatalytic coating is disposed on the anti-reflective coating.

[0014] In still other features, a method includes arranging a plurality of fourth LEDs between pairs of first and second LEDs and between pairs of third LEDs in an array of LEDs including the first, second, and third LEDs that respectively emit red, green, and blue light visible to the human eye, the fourth LEDs emitting violet light not visible to the human eye. The method includes covering the array with a transparent material, and disposing a photocatalytic coating on the transparent material, the photocatalytic coating including a photocatalyst that reacts to ultraviolet radiation present in daylight and to the violet light emitted by the fourth LEDs in the array of LEDs. The method includes selectively turning on the fourth LEDs to activate the photocatalyst in the photocatalytic coating disposed on the transparent material.

[0015] In another feature, the activation of the photocatalyst cleans an exterior surface of the photocatalytic coating.

[0016] In another feature, the photocatalyst includes an oxide of a first metal, and the oxide is doped with a second metal different from the first metal in the oxide. Alternatively, the photocatalyst includes an oxide of a metal, and the oxide is doped with a non-metal.

[0017] In another feature, the method further includes turning on the fourth LED in response to an amount of sunlight around the array being less than or equal to a predetermined threshold.

[0018] In another feature, the method further includes turning on the fourth LED in response to sunlight being present around the array.

[0019] In another feature, the array is disposed in a vehicle, and the method further includes turning on the fourth LED in response to the vehicle being started.

[0020] In another feature, the array is disposed in a vehicle, and the method further includes turning on the fourth LED for a predetermined period of time in response to the vehicle being turned off, and turning off the fourth LED after the predetermined period of time has elapsed.

[0021] In another feature, the array is disposed in a vehicle, and the method further includes turning on the fourth LED in response to an amount of sunlight around the array being less than or equal to a predetermined threshold.

[0022] In another feature, the array is disposed in a vehicle, and the method further includes turning on the fourth LED in response to sunlight being present around the array.

[0023] In another feature, the method further includes disposing an anti-reflective coating on the transparent material, and the photocatalytic coating is disposed on the anti-reflective coating.

[0024] The present disclosure also includes the following technical solutions.

[0025] Scheme 1. A system comprising:

[0026] a display comprising an array of LEDs, the array of LEDs being covered by a transparent material and comprising a plurality of first, second, third, and fourth LEDs respectively configured to emit red, green, blue, and violet light; wherein the red, green, and blue light from the first, second, and third LEDs is visible to the human eye; and wherein the violet light from the fourth LED is not visible to the human eye;

[0027] a photocatalytic coating disposed on the transparent material, the photocatalytic coating comprising a photocatalyst that reacts to ultraviolet radiation present in sunlight and to the violet light emitted by the fourth LED in the array of LEDs; and

[0028] a controller configured to selectively turn on the fourth LED to activate the photocatalyst in the photocatalytic coating disposed on the transparent material.

[0029] Scheme 2. The system of Scheme 1, wherein the activation of the photocatalyst cleans an outer surface of the photocatalytic coating.

[0030] Scheme 3. The system of Scheme 1, wherein:

[0031] the photocatalyst comprises an oxide of a first metal, and wherein the oxide is doped with a second metal that is different from the first metal in the oxide; or

[0032] the photocatalyst comprises an oxide of a metal, and wherein the oxide is doped with a non-metal.

[0033] Scheme 4. The system of Scheme 1, wherein the controller is structured to turn on the fourth LED in response to an amount of sunlight around the display being less than or equal to a predetermined threshold.

[0034] Scheme 5. The system of Scheme 1, wherein the controller is structured to turn on the fourth LED in response to sunlight being present around the display.

[0035] Scheme 6. A vehicle comprising the system of Scheme 1, wherein the controller is structured to turn on the fourth LED in response to the vehicle being started.

[0036] Scheme 7. A vehicle comprising the system of Scheme 1, wherein the controller is structured to:

[0037] turn on the fourth LED for a predetermined period of time in response to the vehicle being turned off; and

[0038] turn off the fourth LED after the predetermined period of time has elapsed.

[0039] Scheme 8. A vehicle comprising the system of Scheme 1, wherein the controller is structured to turn on the fourth LED in response to an amount of sunlight around the display being less than or equal to a predetermined threshold.

[0040] Scheme 9. A vehicle comprising the system of Scheme 1, wherein the controller is structured to turn on the fourth LED in the presence of sunlight around the display.

[0041] Scheme 10. The system of Scheme 1, wherein the display further comprises an anti-reflective coating disposed on the transparent material, and wherein the photocatalytic coating is disposed on the anti-reflective coating.

[0042] Scheme 11. A method comprising:

[0043] In an LED array comprising first, second and third LEDs which respectively emit red, green and blue light visible to the human eye, a plurality of fourth LEDs are arranged between pairs of the first and second LEDs and between pairs of the third LEDs, the fourth LEDs emitting violet light not visible to the human eye;

[0044] covering the array with a transparent material;

[0045] providing a photocatalytic coating on the transparent material, the photocatalytic coating comprising a photocatalyst which is reactive to ultraviolet radiation present in sunlight and to the violet light emitted by the fourth LEDs in the LED array; and

[0046] selectively switching on the fourth LEDs to activate the photocatalyst in the photocatalytic coating provided on the transparent material.

[0047] Scheme 12. The method of scheme 11, wherein the activation of the photocatalyst cleans an outer surface of the photocatalytic coating.

[0048] Scheme 13. The method of scheme 11, wherein:

[0049] the photocatalyst comprises an oxide of a first metal, and wherein the oxide is doped with a second metal different from the first metal in the oxide; or

[0050] the photocatalyst comprises an oxide of a metal, and wherein the oxide is doped with a non-metal.

[0051] Scheme 14. The method of scheme 11, further comprising switching on the fourth LEDs in response to an amount of sunlight around the array being less than or equal to a predetermined threshold.

[0052] Scheme 15. The method of scheme 11, further comprising switching on the fourth LEDs in response to sunlight being present around the array.

[0053] Scheme 16. The method of scheme 11, wherein the array is arranged in a vehicle, the method further comprising switching on the fourth LEDs in response to the vehicle being started.

[0054] Scheme 17. The method of scheme 11, wherein the array is arranged in a vehicle, the method further comprising:

[0055] switching on the fourth LEDs for a predetermined period of time in response to the vehicle being turned off; and

[0056] switching off the fourth LEDs after the predetermined period of time has elapsed.

[0057] Scheme 18. The method of Scheme 11, wherein the array is disposed in a vehicle, the method further comprising turning on the fourth LED in response to an amount of daylight around the array being less than or equal to a predetermined threshold.

[0058] Scheme 19. The method of Scheme 11, wherein the array is disposed in a vehicle, the method further comprising turning on the fourth LED in the presence of daylight around the array.

[0059] Scheme 20. The method of Scheme 11, further comprising disposing an anti-reflective coating on the transparent material, wherein the photocatalytic coating is disposed on the anti-reflective coating.

[0060] Other aspects of the applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF DRAWINGS

[0061] The present disclosure will become more fully understood from the detailed description and drawings, in which:

[0062] Figure 1 An example of an array of red, green, and blue LEDs is shown;

[0063] Figure 2 An example of an array of red, green, and blue LEDs of Figure 1 plus purple LEDs disposed between the red, green, and blue LEDs is shown;

[0064] Figure 3 An example of a cross-section of a display using an array of red, green, blue, and purple LEDs of Figure 2 wherein a photocatalytic coating is disposed on the display is shown;

[0065] Figure 4 An array of red, green, blue, and purple LEDs of Figure 2 is shown in further detail;

[0066] Figure 5 A system is shown that includes an array of red, green, blue, and purple LEDs of Figure 2 a controller, and a power supply; and

[0067] Figure 6 A method of controlling an array of red, green, blue, and purple LEDs of Figure 5 using a controller and a power supply of Figure 2 is shown.

[0068] In the drawings, reference numerals can be repeated among the figures for like and / or identical elements. DETAILED DESCRIPTION

[0069] Certain LED-based displays are coated with a photocatalytic coating that, when activated by light (e.g., ultraviolet radiation from sunlight), breaks down and eliminates substances such as fingerprints, oily residues, and other debris from the surface of the display. The photocatalytic coating includes a photocatalyst that is excited by light. Excitation of the photocatalyst by light causes a chemical reaction at the surface of the photocatalytic coating that utilizes water molecules in the air to clean the surface of the photocatalytic coating. The photocatalytic coating is transparent and designed for use with a variety of surfaces, including LED-based displays.

[0070] The photocatalytic coatings generally incorporate a material (e.g., Ti02) that has a band gap in the ultraviolet (UV) and near-UV portions of the light spectrum. As a result, these photocatalytic coatings can be activated by the UV radiation present in sunlight. However, these photocatalytic coatings do not work effectively at night or in non-sunny conditions, such as overcast days, and in vehicles with tinted windows (i.e., when the amount of sunlight is less than or equal to a predetermined threshold). To make the photocatalytic coatings work in such conditions, expensive and bulky UV illuminators are required.

[0071] The present disclosure provides a system that allows photocatalytic coatings to work at night and in non-sunny conditions (i.e., when the amount of sunlight is less than or equal to a predetermined threshold). The system incorporates a violet micro-LED into an array of red, green, and blue (RGB) micro-LEDs of an LED-based display to provide photons that initiate photocatalysis of water and remove fingerprints, oils, and other debris from a photocatalytic coating on the display. Unlike the red, green, and blue light produced by the red, green, and blue micro-LEDs, which are visible to the human eye, the violet micro-LED produces violet light that is different from ultraviolet radiation and is not visible to the human eye, but is absorbed by the photocatalyst in the photocatalytic coating.

[0072] The photocatalyst includes a metal oxide or a doped metal oxide that has a band gap that is tuned to the violet light produced by the violet micro-LED. Specifically, the photocatalyst includes an oxide of a first metal and is doped with a second metal (or non-metal) that is different from the first metal in the oxide. Examples of the photocatalyst include anatase and metal-doped versions of anatase, which is a metastable mineral form of Ti02. Examples of metals for doping the metal oxide include any transition metal listed in the d-block of the periodic table. Examples of non-metals that can be used as dopants to tune the band gap include nitrogen, fluorine, and the like.

[0073] Doping alters the band gap of the metal oxide, enabling the photocatalyst to be activated not only by ultraviolet radiation from sunlight but also by violet light generated by violet micro-LEDs. This feature allows for the activation of the photocatalyst using violet light generated by violet micro-LEDs and enables self-cleaning of the LED-based display surface in the absence of sunlight (e.g., at night, on cloudy days, in vehicles with tinted windows, etc.). These and other features of this disclosure are further described in detail below.

[0074] Figure 1 A microLED array 100 comprising red, green, and blue (RGB) microLEDs is shown for an LED-based display. The red, green, and blue (RGB) microLEDs are indicated accordingly by reference numerals 102, 104, and 106. Although not shown, the microLED array 100 is fabricated on a silicon substrate and covered with glass or other transparent material coated with a photocatalytic coating that is also transparent. This photocatalytic coating comprises a photocatalyst (e.g., TiO2) that requires ultraviolet light for activation.

[0075] Figure 2 A microLED array 150 for an LED-based display according to the present disclosure is shown. The microLED array 150 includes red, green, and blue (RGB) microLEDs 102, 104, and 106. Additionally, as shown, the microLED array 150 also includes a purple microLED 152 disposed between the RGB microLEDs 102, 104, and 106. For example, the purple microLED 152 is disposed between each pair of red and green microLEDs 102, 104. Furthermore, the purple microLED 152 is disposed between each pair of blue microLEDs 106. Therefore, the microLED array 150 is referred to as an RGBV microLED array 150, which includes RGBV microLEDs 102, 104, 106, and 152.

[0076] See below for reference. Figures 3-5 As explained, the micro-LED array 150 is fabricated on a silicon substrate and covered with glass or other transparent material coated with a photocatalytic coating. This transparent photocatalytic coating comprises a photocatalyst. The photocatalyst comprises a metal oxide or doped metal oxide having a band gap tuned to the violet light emitted by the violet micro-LED 152. Examples of the photocatalyst include anatase and metal-doped anatase. Alternatively, non-metals such as nitrogen or fluorine can be used as dopants to tune the anatase band gap. The photocatalyst works with ultraviolet light present in sunlight and with the violet light emitted by the violet micro-LED 152.

[0077] Figure 3 An example of a cross-section through an LED-based display 200 according to the present disclosure is shown. Figure 3 The elements shown in the Figures are not drawn to scale. The LED-based display 200 comprises a substrate (e.g. a silicon substrate) 202. The substrate 202 comprises circuitry for controlling the RGBV micro-LEDs 102, 104, 106, 152 of the micro-LED array 150, as well as power and control lines. The micro-LED array 150 is arranged on the substrate 202. The RGBV micro-LEDs 102, 104, 106, 152 of the micro-LED array 150 are connected to the circuitry and power and control lines in the substrate 202 using vias (not shown). Figure 4 The micro-LED array 150 is shown in further detail in Figure 2. Figure 5 An example of a controller for controlling the micro-LED array 150 is shown in Figure 3.

[0078] A cover 204 of glass or other transparent material is arranged over the micro-LED array 150. The outer surface of the cover 204 can optionally be coated with a coating of anti-reflective material 206 (hereinafter anti-reflective coating 206). A coating of photocatalytic material 208 (hereinafter photocatalytic coating 208) is applied on top of the anti-reflective coating 206 (or on the outer surface of the cover 204 if the anti-reflective coating 206 is omitted).

[0079] The photocatalytic coating 208 comprises a photocatalyst comprising a metal oxide or doped metal oxide having a band gap tuned to the violet light produced by the violet micro-LEDs 152 of the micro-LED array 150. In particular, the photocatalyst comprises an oxide of a first metal and the oxide is doped with a second metal (or non-metal) different to the first metal in the oxide. Examples of the photocatalyst include anatase and metal-doped forms of anatase, which is a metastable mineral form of Ti02. Examples of metals for doping the metal oxide include any transition metal listed in the d-block of the periodic table. Alternatively, a non-metal such as nitrogen, fluorine can be used as a dopant.

[0080] The doping changes the band gap of the metal oxide so that the photocatalyst is activated not only by ultraviolet radiation from sunlight, but also by the violet light produced by the violet micro-LEDs 152 of the micro-LED array 150. Since the photocatalyst works with both the ultraviolet light present in sunlight and the violet light emitted by the violet micro-LEDs 152, the self-cleaning of the outer surface of the photocatalytic coating 208 can be initiated by switching on the violet micro-LEDs 152 of the micro-LED array 150 in the absence of sunlight (e.g. at night, on a cloudy day, in a vehicle with tinted windows, etc.).

[0081] Figure 4 A micro-LED array 150 is shown that includes RGBV micro-LEDs 102, 104, 106, 152. The RGBV micro-LEDs 102, 104, 106, 152 are not shown as separate elements in Figure 4 but are shown as separate elements in Figure 5 Instead, each group of RGBV micro-LEDs 102, 104, 106, 152 is shown collectively as an element 154 in Figure 4 In other words, each element 154 shown in Figure 4 includes a respective one of the RGBV micro-LEDs 102, 104, 106, 152.

[0082] The micro-LED array 150 includes a plurality of groups of switches (shown as Sws) 160 connected to the RGBV micro-LEDs 102, 104, 106, 152 (i.e., to the elements 154). Each group of switches 160 is connected to a respective group of RGBV micro-LEDs 102, 104, 106, 152 (i.e., to one of the elements 154). Each group of switches 160 includes four switches (shown in Figure 5 ) that are respectively connected to the respective RGBV micro-LEDs 102, 104, 106, 152 in one of the elements 154. Again, the four switches in each group of switches 160 are not shown as separate elements in Figure 4 but are shown as separate elements in Figure 5

[0083] The micro-LED array 150 also includes a plurality of power supply lines 170, a plurality of power return lines 172, and a plurality of control lines 174. For example, the power supply lines 170 can be connected to first ends of the RGBV micro-LEDs 102, 104, 106, 152. The power return lines 172 can be connected to second ends of the RGBV micro-LEDs 102, 104, 106, 152 via the respective switches 160. The control lines 174 can be connected to control terminals of the switches 160 (e.g., to gates of transistors used as the switches 160). As described below with reference to Figure 5 , a controller can control these switches and selectively turn on and off any of the RGBV micro-LEDs 102, 104, 106, 152 in the micro-LED array 150.

[0084] Figure 5 ​A block diagram of a system 250 is shown, which includes the micro-LED array 150, a display controller 252, and a power source (e.g., a battery of a vehicle) 254. Each set of switches 160 includes four switches 160-1, 160-2, 160-3, 160-4 (collectively, switches 160). The controller 252 controls the switches 160 to turn on and off any RGBV micro-LEDs 102, 104, 106, 152 in the micro-LED array 150. For example, to perform the cleaning process described above, the controller 252 can turn on all of the purple micro-LEDs 152 by controlling the switches 160-4 each time the vehicle is started. Alternatively, the controller 252 can turn on all of the purple micro-LEDs 152 for a predetermined period of time (e.g., 4 hours) by controlling the switches 160-4 each time the vehicle is turned off. Alternatively, the controller 252 can turn on all of the purple micro-LEDs 152 by controlling the switches 160-4 each time a sensor in the vehicle detects that the amount of daylight around the display is less than or equal to a threshold value (e.g., when the ambient environment of the vehicle is darker than a threshold value).

[0085] The purple light from the purple micro-LEDs 152 activates the photocatalytic coating 208 on the cover 204 of the display 200. The purple light from the purple micro-LEDs 152 initiates chemical reactions on the surface of the photocatalytic coating 208. These chemical reactions clean the surface of the photocatalytic coating 208. Thus, the cleaning process can occur in the presence of daylight, as the UV radiation in the daylight can activate the photocatalytic coating 208 on the cover 204 of the display 200. Additionally, in the absence of daylight, the cleaning process can be initiated by turning on the purple micro-LEDs 152, as the purple light from the purple micro-LEDs 152 can activate the photocatalytic coating 208 on the cover 204 of the display 200.

[0086] In some implementations, the controller 252 can turn on only some, but not all, of the purple micro-LEDs 152. For example, the controller 252 can turn on only alternate ones of the purple micro-LEDs 152. Other patterns can also be used. Furthermore, the controller 252 can control the intensity of the purple micro-LEDs 152 by controlling the current provided to the purple micro-LEDs 152. The controller 252 can control at least one of the intensity and the pattern of the turned-on purple micro-LEDs 152 according to factors such as the amount of daylight present around the display 200. The controller 252 can control both the intensity and the pattern of the turned-on purple micro-LEDs 152 together (i.e., in coordination) to effectively achieve cleaning.

[0087] Figure 6A flowchart of the method 300 performed by the controller 252 is shown. In the following description, the term "control" refers to the operations performed by the controller 252. At 302, control determines whether the vehicle is started. If the vehicle is started, at 304, control turns on the purple micro-LEDs 152, and control returns to 302. If the vehicle is not started, at 306, control determines whether the ambient environment of the vehicle is dark (i.e., whether the amount of daylight around the display is less than or equal to a predetermined threshold; e.g., whether there is not enough daylight to activate the photocatalyst in the photocatalytic coating 208). If the ambient environment of the vehicle is not dark (i.e., if the amount of daylight around the display is greater than or equal to the predetermined threshold; e.g., if there is enough daylight to activate the photocatalyst in the photocatalytic coating 208), control ends.

[0088] If the ambient environment of the vehicle is dark (i.e., if the amount of daylight around the display is less than or equal to the predetermined threshold; e.g., if there is not enough daylight to activate the photocatalyst in the photocatalytic coating 208), control proceeds to 308. At 308, control turns on the purple micro-LEDs 152 at full intensity for a predetermined period of time (e.g., up to four hours or an amount of time empirically determined to be sufficient to clean the surface of the photocatalytic coating 208). When the predetermined period of time has elapsed, control ends.

[0089] Alternatively, instead of beginning at 302, control begins at 310. At 310, control determines whether a cleaning mode is activated (e.g., by the vehicle owner). If the cleaning mode is not activated, control ends. If the cleaning mode is activated, at 312, control turns on the purple micro-LEDs 152 at the same time the vehicle is started. At 314, control turns on the purple micro-LEDs 152 for a predetermined period of time (e.g., up to four hours or an amount of time empirically determined to be sufficient to clean the surface of the photocatalytic coating 208). At 316, control determines whether the predetermined period of time has elapsed. When the predetermined period of time has elapsed, control ends.

[0090] The teachings of the present disclosure are not limited to LED-based displays used in vehicles. Rather, the teachings are applicable to LED-based displays used in other devices, such as computers, mobile devices, televisions, kiosks, teller machines, and home appliances. The teachings are applicable in these other devices so long as the LED-based display includes a photocatalytic coating according to the present disclosure, and a power source is available according to the present disclosure to turn on the purple micro-LEDs incorporated in the LED-based display.

[0091] The foregoing description is merely illustrative in nature and is not intended to limit the disclosure, its application or uses. The broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be limited to such examples. Other modifications will be apparent from consideration of the specification and the following claims in view of the prior art.

[0092] It should be understood that one or more steps within a method can be executed in various orders (or concurrently) without altering the principles of the present disclosure. Further, although each of the embodiments described herein is described as having certain features, any one or more of those described features can be implemented in any particular embodiment and / or in combination with other features in any other embodiments, even if that combination is not explicitly described. In other words, there is no limitation on the combination of features in the described embodiments.

[0093] Spatial and functional relationships between elements (for example, between circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "next to," "on top of," "above," "below," and "disposed." Unless specifically described as "direct," relationships between components (or steps), as described above, can be indirect as well - for example, via an intermediary component (or step) - unless specifically stated otherwise. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed terms. The phrase at least one of, when used in the context of a list of two or more items, means at least one of the listed items can be present, and a plurality of one of the items can be present. As used herein, the expression "at least one of" is intended to mean any one of recited items and any combination of one or more of the recited items.

[0094] In the drawings, the direction of an arrow, as indicated by the arrowhead, usually demonstrates the information flow (e.g., data or instructions) that is of interest to the illustration. For example, when element A and element B exchange a variety of information but the information that is of interest to the illustration is the information that passes from element A to element B, an arrow can point from element A to element B. The arrow does not indicate that no other information is transmitted from element B to element A. Further, the arrow can indicate that information that is of interest to the illustration passes from element A to element B, but not the other way around. The absence of an arrow between two elements does not mean that no information passes between the elements. Further, the presence of an arrow does not mean that information cannot pass between the elements. In other words, the absence or presence of an arrow between two elements does not indicate that no other element can be present between the elements. The skilled artisan will understand that, for ease of illustration, only those elements necessary to conceptual clarity are often depicted. Thus, the absence or presence of an arrow between two elements does not indicate that no other element can be present between the elements.

[0095] In this application, including the following claims, the term "controller" can be replaced by the term "circuit." The term "controller" can refer to one or more of the following, a portion of one or more of the following, or include one or more of the following: an application-specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, for example, in a system-on-chip.

[0096] The term "code," as used in the specification above, can include software, firmware and / or microcode, and can refer to program, routines, functions, classes, data structures, and / or objects. The term "memory circuit" is a subset of the term "computer-readable medium." The term "computer-readable medium," as used in the specification, does not encompass transitory, propagating signals per se (e.g., a carrier wave of a signal); thus, the term "computer-readable medium" can be considered tangible or non-transitory. Non-limiting examples of non-transitory, tangible computer-readable media are nonvolatile memory circuits (e.g., a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (e.g., a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (e.g., an analog or digital magnetic tape or a hard disk drive), and optical storage media (e.g., a CD, a DVD, or a Blu-ray disc).

[0097] The apparatus and methods described in this application can be partially or entirely implemented by special purpose computers created by customizing general purpose computers to perform one or more specific functions embodied in the computer programs. The aforementioned function blocks, flowchart components, and other elements are as software specifications that are converted by a technician or programmer into computer programs.

[0098] The computer programs include processor-executable instructions stored on at least one non-transitory, tangible computer-readable medium. The computer programs can also include or rely on stored data. The computer programs can encompass a basic input / output system (BIOS) that interacts with the hardware of the special purpose computer, device drivers that interact with particular devices of the special purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0099] The computer program can include: (i) descriptive text to be parsed, such as HTML (HyperText Markup Language), XML (Extensible Markup Language), or JSON (JavaScript Object Notation); (ii) assembly code; (iii) object code generated by a compiler; (iv) source code for an interpreter; (v) source code for a just-in-time compiler; etc. As examples only, source code can be written using syntax from languages including C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Java®, Fortran, Perl, Pascal, Curl, OCaml, Javascript®, HTML5 (HyperText Markup Language Version 5), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Flash®, Visual Basic®, Lua, MATLAB, SIMULINK, and Python®.

Claims

1. A system for self-cleaning of a display, comprising: the display including an array of LEDs covered by a transparent material and including a plurality of first, second, third, and fourth LEDs respectively configured to emit red, green, blue, and violet light; wherein the red, green, and blue light from the first, second, and third LEDs is visible to the human eye; and wherein the violet light from the fourth LED is not visible to the human eye; a photocatalytic coating disposed on the transparent material, the photocatalytic coating including a photocatalyst that reacts to ultraviolet radiation present in sunlight and to the violet light emitted by the fourth LED in the array of LEDs; and a controller configured to selectively turn on the fourth LED to activate the photocatalyst in the photocatalytic coating disposed on the transparent material, wherein the controller is configured to turn on the fourth LED in response to an amount of sunlight around the display being less than or equal to a predetermined threshold, and wherein the activation of the photocatalyst cleans an outer surface of the photocatalytic coating to achieve self-cleaning of the display.

2. The system of claim 1, wherein: the photocatalyst includes an oxide of a first metal, and wherein the oxide is doped with a second metal different from the first metal in the oxide; or the photocatalyst includes an oxide of a metal, and wherein the oxide is doped with a non-metal.

3. The system of claim 1, wherein, the controller is configured to turn on the fourth LED in response to sunlight being present around the display.

4. The system of claim 1, wherein, the display further includes an anti-reflective coating disposed on the transparent material, and wherein the photocatalytic coating is disposed on the anti-reflective coating.

5. A vehicle comprising the system of claim 1, wherein, the controller is configured to turn on the fourth LED in response to the vehicle being started.

6. A vehicle comprising the system of claim 1, wherein, the controller is configured to: turn on the fourth LED for a predetermined period of time in response to the vehicle being turned off; and turn off the fourth LED after the predetermined period of time has elapsed.

7. A vehicle comprising the system of claim 1, wherein, the controller is configured to turn on the fourth LED in response to an amount of sunlight around the display being less than or equal to a predetermined threshold.

8. A vehicle comprising the system of claim 1, wherein, the controller is configured to turn on the fourth LED in the presence of sunlight around the display.

9. A method for self-cleaning of a display, comprising: arranging a plurality of fourth LEDs between pairs of first and second LEDs and between pairs of third LEDs in an array of LEDs including the first, second, and third LEDs respectively emitting red, green, and blue light visible to the human eye, the fourth LEDs emitting violet light not visible to the human eye; covering the array by a transparent material; disposing a photocatalytic coating on the transparent material, the photocatalytic coating including a photocatalyst that reacts to ultraviolet radiation present in sunlight and to the violet light emitted by the fourth LEDs in the array of LEDs; and and selectively turning on the fourth LED to activate the photocatalyst in the photocatalytic coating disposed on the transparent material, wherein the selectively turning on the fourth LED includes turning on the fourth LED in response to an amount of sunlight surrounding the array being less than or equal to a predetermined threshold, and wherein the activation of the photocatalyst cleans an outer surface of the photocatalytic coating to enable self-cleaning of the display.

10. The method of claim 9, wherein: the photocatalyst includes an oxide of a first metal, and wherein the oxide is doped with a second metal different from the first metal in the oxide; or the photocatalyst includes an oxide of a metal, and wherein the oxide is doped with a non-metal.

11. The method of claim 9, further comprising turning on the fourth LED in response to sunlight being present surrounding the array.

12. The method of claim 9, wherein, the array is disposed in a vehicle, the method further comprising turning on the fourth LED in response to the vehicle being started.

13. The method of claim 9, wherein, the array is disposed in a vehicle, the method further comprising: turning on the fourth LED for a predetermined period of time in response to the vehicle being turned off; and turning off the fourth LED after the predetermined period of time has elapsed.

14. The method of claim 9, wherein, the array is disposed in a vehicle, the method further comprising turning on the fourth LED in response to an amount of sunlight surrounding the array being less than or equal to a predetermined threshold.

15. The method of claim 9, wherein, the array is disposed in a vehicle, the method further comprising turning on the fourth LED in response to sunlight being present surrounding the array.

16. The method of claim 9, further comprising disposing an anti-reflective coating on the transparent material, wherein, the photocatalytic coating is disposed on the anti-reflective coating.

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