WO2022249201A1

WO2022249201A1 - Laminated structure with micro light emissive unit for display in vehicle

Info

Publication number: WO2022249201A1
Application number: PCT/IN2022/050490
Authority: WO
Inventors: Arunvel Thangamani; Naveinah CHANDRASEKARAN; Samson Richardson D
Original assignee: Saint-Gobain Glass France
Priority date: 2021-05-27
Filing date: 2022-05-25
Publication date: 2022-12-01

Abstract

The present disclosure provides a laminated structure (100) for display in a vehicle. The laminated structure comprises at least a first substrate (101), one or more interlayers (102) and at least a second substrate (103) and at least one light emissive unit (104) for display in the laminated structure. The at least one light emissive unit is adapted to be embedded between the first substrate and second substrate and said at least one light emissive unit (104) is operably coupled with at least one lighting control unit (105). The lighting control unit (105) is configured to adjust the illumination of the at least one light emissive unit without affecting transparency of the laminated structure. The laminated structure is further capable of preventing formation of ghost images. A system for display in vehicle and method of incorporating a light emissive unit for display in the laminated structure are further provided.

Description

LAMINATED STRUCTURE WITH MICRO LIGHT EMISSIVE UNIT FOR DISPLAY IN VEHICLE

TECHNICAL FIELD

The present disclosure relates generally to a glazing of a vehicle with display units or lighting elements. It particularly relates to a laminated glazing of a vehicle integrated with light emitting diodes, and more particularly to a laminated glazing with micro light emissive unit embedded therein.

BACKGROUND

Background description includes information that may be useful in understanding the present disclosure. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

It is known to one skilled in the art that glazing refers to any and all the glass or similar material within a structure or the installation of any piece of glass or the similar material within a sash or frame. Glazing referred to herein may include the glass or the polymer windows or doors of an automobile. The encapsulation for a glazing includes a process to obtain a frame around the glass or polymer layer by injecting a polymer on its border through a framing mold. Encapsulation may be used on windscreens, side windows and rear windows. For laminated glazing, two or more layers of glass or a similar material, are fused together with an interlayer in the middle. The fusion is completed with pressure and heat and it prevents the sheets of glass or the similar material from breaking. While some pieces of glass or the similar material might end up breaking into larger pieces, those pieces will stay together with the help of the interlayer, making it shatterproof. Further it is known that annealed glass is one that has been slowly cooled, thereby making the glass stronger, more durable and less likely to break. Tempered glass on the other hand, is made by putting the outer surfaces into compression and the inner surfaces into tension. The glazing may also be of annealed glass or tempered glass.

Display in vehicle is known in the art and are essential considering features such as the driver information systems (DIS) that are operational in a vehicular environment. Proper and relevant in-vehicle and out-vehicle displays are desirable for improved user experiences and also to consider the safety aspects. It is desired to have displays that do not adversely affect the driver’s visibility. Accordingly, when having display in an automotive glazing of vehicle, it becomes crucial to consider certain aspects such as brightness of the display or the lighting element and formation of secondary images in laminated glazing.

Reference is made to FR3089882A1 that discloses about display in windshield of a vehicle for display of images, transmitted by a reversing camera, as soon as the driver engages a reverse gear of the vehicle. The image brightness adjustment automatically adjusts to the light in the vehicle environment. The screen structure is made up of liquid metal, a shape memory alloy or amorphous metal.

Another reference is made to US20150375673A1 that discloses systems and methods for vehicle glass panels with integrated lighting components. In the perimeter margin region of the lighting assembly disclosed therein includes a serigraphic layer, and the substantially planar light component is disposed between the serigraphic layer and a surface of the glass panel. But this solution is as such not directed at embedding display in laminated glazing.

A further reference is made to W02020050062A1 that discloses transparent display device, glass plate with transparent display device, laminated glass with transparent display device, and moving body. This transparent display device is provided with a first transparent base material, light emitting parts which are arranged on the first transparent base material, and a wiring part which is connected to the light emitting parts. However, the solutions disclosed in the prior art do not provide for auto-brightness control of the display unit or lighting element in a laminated glazing based on ambient lighting inside and outside of the vehicle and it do not render any solutions for avoiding the formation of ghost images in the laminated glazing due to second reflections. Solutions known in the art involve the increase or decrease in brightness around the display and not the in the display itself to increase the display contrast. However, such solution will result in affecting the transparency of the glazing and thus will adversely affect the visibility. Such solutions are hence not suitable for automotive glazing such as windshield. Therefore, there is a need for eliminating existing challenges in the display in laminated glazing for automotive.

SUMMARY OF THU DTSCUOSTTRU

An object of the present invention is to overcome the drawbacks of the prior art and provide an improved solution over the prior art.

Another object of the present invention is to provide a laminated glazing for a vehicle having micro-light emissive unit for display with display brightness adjustment based on the ambient lighting condition without affecting the transparency.

A further object of the present invention is to provide a laminated glazing with display that prevents the formation of ghost images in the laminated glazing.

A further object of the present invention is to provide a system for display in vehicle with display brightness adjustment feature.

A still further object of the present invention is to provide a method of manufacture of a laminated display unit having micro-light emissive unit. These and other objects of the invention are achieved by the following aspects of the invention. The following disclosure presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This presents some concept of the invention in a simplified form to a more detailed description of the invention presented later. It is a comprehensive summary of the disclosure and it is not an extensive overview of the present invention. The intend of this summary is to provide a fundamental understanding of some of the aspects of the present invention.

In an aspect of the present invention is disclosed a laminated structure for display in a vehicle. The structure comprises at least a first substrate, one or more interlayers and at least a second substrate, in which the first substrate and the second substrate are held together by the one or more interlayers therebetween. The structure further includes at least one light emissive unit adapted for display in the laminated structure, wherein the at least one light emissive unit is adapted to be embedded between the first substrate and second substrate and said at least one light emissive unit is operably coupled with at least one lighting control unit. The lighting control unit is outside the laminated structure. The laminated structure further includes a means adapted for preventing formation of secondary images on surfaces of the layers of the laminate. The at least one lighting control unit is configured to adjust the illumination of the at least one light emissive unit without affecting transparency of the laminated structure.

In aspect of the invention is disclosed a system for display in glazing for a vehicle, wherein the glazing comprises a laminated structure. The system comprises a glazing having at least one light emissive unit including micro light emitting diode (microLED) disposed within the glazing and adapted for display in the glazing and a means adapted for preventing formation of secondary images in the glazing; wherein the glazing is either laminated glazing or non-laminated glazing. The system further includes at least one lighting control unit operably coupled with said at least one light emissive unit for adjusting the illumination of the at least one light emissive unit without affecting transparency of the glazing and a control unit. The control unit is operably coupled to enable, disable and/or control the display in the glazing, wherein an electronic control unit of the vehicle is operably coupled with said control unit.

In yet another aspect of the invention is disclosed a method of incorporating a light emissive unit for display in the laminated structure. The method comprises bending a flat substrate of glass or polymer as a first substrate of the laminated structure, printing the contact layers on said substrate, wherein a specification of the contact layers is based on the array of microscopic LEDs of the light emissive unit, printing or transferring the flexible array of microscopic LEDs on to the contact layer, bonding the contact layer to the flexible array of microscopic LEDs via wire bonding and laminating the first substrate with one or more interlayers and second substrate for form shatter-proof structure with embedded display.

The present invention provides a microLight emissive unit in laminated structure. It includes direct bonding of microLED. It further includes displays on glass as a substrate will reduce thickness of the laminated glazing and reduce the additional process step involved. Furthermore, the solution provides an auto brightness adjustment circuit based on ambient lighting condition will enable using the laminate display structure for multiple use cases as a dynamic display. In the disclosed solution addition of collimating reflectors or polarizers will avoid secondary or ghost image formation in the embedded transparent display in the glass.

The significant features of the present invention and the advantages of the same will be apparent to a person skilled in the art from the detailed description that follows in conjunction with the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The following briefly describes the accompanying drawings, illustrating the technical solution of the embodiments of the present invention or the prior art, for assisting the understanding of a person skilled in the art to comprehend the invention. It would be apparent that the accompanying drawings in the following description merely show some embodiments of the present invention, and persons skilled in the art can derive other drawings from the accompanying drawings without deviating from the scope of the disclosure.

FIGs. 1 A and IB illustrate exemplary embodiments of the laminated structure with a light emissive unit according to the present invention.

FIG. 2 illustrates an embodiment of the structure of the Structure of light emissive unit according to an embodiment of the present invention.

FIGs. 3A-3C illustrate a system for display in a laminated glazing with light emissive unit and the mode of operation of the control unit according to the present invention.

FIGs. 4A-4C illustrate the process of lamination of micro light emissive unit according to the present invention.

FIG. 5A illustrates the variation in direct radiation over a period of 24 hours for a given day according to an embodiment of the present invention.

FIGs. 5B and 5C illustrate the different means of embedding collimators and polariser according to an embodiment of the present invention.

Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the disclosure.

PET ATT, ED DESCRIPTION

The present invention is now discussed in more detail referring to the drawings that accompany the present application. In the accompanying drawings, like and/or corresponding elements are referred to by like reference numbers. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

The terms and words used in the following description are not limited to the bibliographical meanings and the same are used to enable a clear and consistent understanding of the invention. Accordingly, the terms/phrases are to be read in the context of the disclosure and not in isolation. Additionally, descriptions of well- known functions and constructions are omitted for clarity and conciseness.

Reference is made to FIG. 1A of the present invention that discloses a laminated structure (100) according to an embodiment of the present invention. The laminated structure as defined herein is suitable for automotive glazing. The structure comprises at least a first substrate (101), one or more interlayers (102) and at least a second substrate (103). The first substrate and the second substrate are held together by the one or more interlayers for imparting the shatterproof quality to the laminate or laminated structure. The first substrate and second substrate of the laminated structure may be made of glass or polymer material, however not limited to said materials. The laminated structure or assembly may be either a flat structure or may be curved structure such as and not limited to a windshield or backlite in a vehicle. Each of the first and second substrates of the laminate or laminated structure may have inner and outer surfaces or faces. The laminated structure with an embedded display unit may be transparent. The laminated structure may be adapted to exhibit at least 10 % - 90 % or more of transparency, preferably, it may exhibit a transparency of at least 40% or more. One of the factors that governs the transparency of the lamination in a vehicle glazing is the regulatory norms of a country in which the vehicle is intended to be used. The laminated structure (100) for display in a vehicle includes a means (107) adapted for preventing formation of secondary images on surfaces the layers of the laminate. The means (107) adapted for preventing formation of secondary images in the laminated structure includes a layer or coating of collimating reflectors to on the first substrate, or the second or the one or more interlayers.

The glazing referred to herein may be any of windshield, sidelite, quaterlite, backlite, sunroof, part of door of the vehicle and said vehicle is any of car, train or aircraft. The glazing structure or assembly as disclosed herein may find applications to depict night sky in sunroof of a car or advertisement in sliding doors of trains. Further provided is a system for display in glazing for a vehicle with means for energy efficiency.

In an embodiment of the present invention, the laminate or laminated structure comprises at least one light emissive unit or a display unit (104) embedded therein, as depicted in the FIG. 1A. The at least one light emissive unit may comprise a microLED based display unit. The at least one light emissive unit, comprises a stacked structure having multiple layers for display, embedded within the laminated structure. In an implementation of the present invention, it is preferred to have a thickness of minimum 2.1 mm for the first and second substrates. The at least one light emissive unit (104) is adapted for display in the laminated structure. It is embedded between the first substrate and second substrate, preferably disposed on the interlayer of the structure. The first or second laminate substrate of the structure or the one or more interlayers may be either coated or be embedded with collimating reflectors to advantageously prevent the formation of ghost image or secondary image formation. Ghost images can hinder the view through the lamination in the vehicle glazing. The laminate structure has more than one substrate held in an assembly, which may cause the formation of ghost image due to reflection from multiple surfaces. However, with the coating of the collimating reflectors the divergent light beams are prevented from forming ghost images by the transparent substrates in the laminated structure with the microLED layers bonded to a contact layer. FIG IB shows a block diagram of an exemplary embodiment of the layers with collimating reflectors on the interlayers. It depicts an exemplary embodiment of the laminated structure such a windshield having two interlayers. In the disclosed embodiment, two of said interlayers are having collimators or collimating reflectors on them. The light emissive unit is disposed therebetween the interlayers in the laminated glazing.

The first or second substrate of the laminate or the one or more interlayers may be either coated or be embedded with polarizing film to advantageously avoid display visibility from the opposite side of viewer or secondary image formed by the transparent substrate in with microLED layers are bonded to contact layers. Further, the polarizing film is capable of reflection of light in one direction only, therefore, the display may be visible from the side of the transparent laminate structure while it will not be visible from the other side. This may be used when one needs to selectively display on the glazing to outside of the vehicle or to the inside of the vehicle. In an embodiment of the present invention, said light emissive unit (104) is operably coupled with at least one lighting control unit (105) seen in FIG. 1A. The lighting control unit (105) is outside the laminated structure. In case of the laminated structure being within vehicle glazing, the lighting control unit (105) may be suitably disposed around the electronic control unit or around the periphery of the glazing, however not limited to these locations on the vehicle. The lighting control unit (105) is configured to adjust the illumination of the at least one light emissive unit without affecting transparency of the laminated structure. The lighting control unit is capable of enabling auto-brightness function on the display depending on ambient lighting condition sensing. The lighting condition sensing may be performed by an ambient light sensor and the lighting control unit may include a power control unit capable of supplying power to the display for depending on the ambient lighting condition sensed by said sensor. Furthermore, the adjustment of the brightness may also be varied based on other instances such as on the basis of a predefined set value based on time of the day. The brightness may further be varied by the need for display like whether the display to the inside of a vehicle is required or display visibility to the outside is required. The brightness of the display unit is controlled by increasing or decreasing the actual brightness parameter of the display itself and not by bringing about a display contrast by varying the non-display portion of the glazing such by varying the transparency of the non-display portion of the glazing. Therefore, with the disclosed solution the brightness of the display is varied with affecting the transparency of the glazing. In an implementation of the invention, the lighting control unit (105) may include power control unit for enabling auto brightness function depending on ambient lighting condition sensing. It would be appreciated by one skilled in the art that depending on the use of the laminated structure, brightness parameter of the display be varied by varied voltage or varied current, however not limited to these.

Reference is made to FIG. 2 that discloses the stacked structure of the microLED based display unit embedded in the laminate according to an exemplary embodiment of the present invention. The stacked structure or layers comprising a base substrate (211) is adapted for including one or more array of microscopic light emitting diodes (LEDs). Said LEDs are capable of forming the individual display elements. The microLED based display unit further includes a LED driver unit (230) operably connected with the lighting control unit (105) for controlled display in the laminated structure. The LED driver unit (230) is either within the laminated structure or outside the laminated structure. In an exemplary implementation of the invention, the LED driver (230) may be switch or gate like functional module that is capable of allowing the passage of signals upon receiving trigger from the lighting control unit (105). This example of LED driver is by way of explanation only for enhancing the understanding of the skilled person and not by way of limitation. The at least one lighting control unit (105) is configured to adjust the illumination of the light emissive unit based on the input from a light adjustment unit (106). The light adjustment unit may either in the laminated structure or outside the laminated structure. It is based on the input (like signal or data) from the light adjustment unit (106) that the brightness of the light emissive unit or the display unit can be controlled. The light the light adjustment unit (106) may comprise a light detection sensor for sensing the light incident on the laminated structure and/or a timer circuit to track the time of the day. The laminated glass structure with micro light emissive unit thus can facilitate for auto-brightness control of display unit. It may also include some manual trigger for controlling rendering signals to control the brightness of the display.

The microLED display unit may be embedded anywhere on the laminated structure. For instance, if the laminated structure is the glazing of a vehicle such a windshield, the display unit may be in and not limited to in zones A, B, C, of the glazing. It may also be embedded on a ceramic region or a black ceramic painted region (BCP) of the windshield.

In an implementation of this embodiment of the present invention, as depicted in FIG. 2, the light emissive unit of microLED based display comprises a base substrate (211) on to which the other illumination elements of the display is disposed on. The base substrate (211) may be and not limited to a flexible low- temperature polycrystalline silicon, LTPS, polyethylene terephthalate, PET, substrate or a glass substrate or a glass substrate with indium gallium zinc oxide thin film transistors, IGZO TFT. The stacked display further comprises a contact layer (212) adapted for connecting a LED to the LED driver unit (230). The contact layer (212) may connect the LED units to the LED driver unit (230) via the LED backplane. The backplane (213) of the display includes plurality of thin film transistors capable to drive or display the pixel accurately. The backplane (213) may be include a circuit configured for dimming or brightening of the LED display. In an implementation, each microLED may have RGB (red, green, blue) sub-pixels. The backplane (213) is capable of driving said dimming circuit for each pixel to get wide range of brightness and colour gamut. This may be obtained by mixing appropriate combination of colours of red, green and blue of sub-pixels to get the desired colour for a certain application may be obtained. The stacked display further includes a bonding layer (214) capable to bond said LED Circuit and the TFT. The display unit (104) may be connected to the contact layer with the LED driver unit (230) via a flat connector (220) or via a printed connector circuit. The LED driver unit (230) is capable to drive the light emissive unit (104) based on the control signals from the lighting control unit (105). The display further includes plurality of microLED units i.e. a layer like structure comprising PN junction diodes (215) which are the responsible light emitting material. Disposed on said layer of PN junction diodes is a protective layer (216) covering the display unit in the laminate structure from external factors like heat, UV rays and the like. In a preferred example, the protective layer or cover is made of glass or other flexible substrate to protect from environment.

In an implementation of the present invention, the substrate around the microLED may be provided with coating for the glazing, to carry the heat away from the embedded electronics during the process of displaying. Said coatings may be and not limited to silver layers. When the automotive glazing with such coated silver layers are in the open field under harsh sunlight during operation the silver layers may be adapted to as infrared reflective, thereby prevent undesirable heating of the embedded electronics.

In an implementation, the laminated glazing may include a cushioning layer adapted to accommodate the microLED and to absorb the direct pressure over the components thereon. The cushioning layer is essential considering the printing of the electronics during the manufacture of disclosed laminated glazing. Further, the collimating reflectors and the polarizers on the light emissive unit of the laminated glazing prevent the formation of ghost images by preventing secondary reflections on the various layers of the stacked structure and by preventing backscattering of light. The polarizing layer, or the polarizers further provide for selective view of the display. This advantageously avoids display visibility from the opposite side of a viewer or the other side of a BCP. Thus, the disclosed laminated structure with one light emissive unit (104) adapted for display in the laminated structure provides improved performance.

The light emissive unit may include display modules having multiple colours or it may include a mono-colour module. The laminated structure may be a curved structure and accordingly the light emissive unit may have a bending angle of up to 180°. The light emissive unit may be transparent or non-transparent. Backplane (213) of the light emissive material may be made of but not limited to CMOS Chip, Silicon C, Silicon, Graphene based, Sapphire substrate or a combination thereof. The microLED diodes may have common contact layer. The contact layer (212) is electrically conductive and is made of materials like carbon nanotubes, CNT, graphene, silver NW, indium tin oxide NW, polymer nanocomposites. The bonding layer (214) is between the microLED and the contact layer. In a preferred embodiment, the pixel pitch of the microLED may be more than 1 micro-metre. The bonding layer and the contact layer may be transparent. The contact layer may be coated or printed on a flexible substrate or glass. The flexible substrate may be PET, PVB, EVA and the like. In an implementation of the invention, the light emissive unit may have a protective cover face and flexible connector taken out through the glazing. The light emissive unit may be current or voltage driven unit. In an exemplary embodiment of the laminated structure in a vehicle glazing according to the present, the light emissive unit may have a panel size panel size covering up to 90% of laminated structure (say a size of up to 12 inches, but not limited to this). It may have a resolution of at least 50 ppi. The light emissive unit may use power of less than 20 Watts to provide luminosity of up to 2,000,000 nits. The power value of operation may be changed from O.luW to up to 20 Watts for changing luminosity value. The brightness and granularity (of resolution) obtained in the disclosed invention is not obtained by other lighting technologies of prior art. This has been possible since each of the MicroLEDs embedded in the laminate are very small (for example like less 100 pm) and by giving the required current or voltage to it, it is possible to achieve a higher resolution as it is a self-emissive technology.

The microLED PN junction diodes may be separated by an insulation layer or a dielectric layer. This is safeguard a user or driver of the vehicle from being electrocuted in case of scenarios where the laminated structure having the embedded display breaks due to accidents. Additionally, the microLED display is voltage or current driven, in which the power supply may be from separate source suitably disposed around the glazing in a vehicle or via an electronic control unit of the vehicle. In an implementation, power control unit may be included for enabling brightness control function depending on ambient lighting condition sensing.

In an embodiment of the invention disclosed a system comprises a glazing comprising at least one light emissive unit including micro light emitting diode (microLED) disposed within the glazing and adapted for display in the glazing and a means adapted for preventing formation of secondary images in the glazing; wherein the glazing is either laminated glazing or non-laminated glazing. Reference is made to FIG 3 A that shows a system for display in glazing for a vehicle, wherein the glazing comprises the laminated structure in accordance with the present invention. The system further comprises a control unit operably coupled to enable disable and or control the display in the glazing. An electronic control unit of the vehicle is operably coupled with said control unit. The system may include the feature of auto-brightness control feature for adjusting power to the emissive unit thereby controlling the brightness of the display. By varying the power of light emissive unit, it can vary the brightness of the microLED to compensate to the outside brightness either sunlight or approaching vehicle. To use a light sensor to detect the incoming brightness and driver unit to control the power of microLED Display.

In an embodiment of the present invention, the at least one lighting control unit (105) is configured to adjust the illumination of the light emissive unit based on the input from the light adjustment unit. Said light adjustment unit is either in the laminated structure or outside the laminated structure. The light adjustment unit may include one or more sub-modules configured to provide variation in the illumination of the light emissive unit (104). In an implementation of the invention, such as shown in FIG. 3B the lighting control unit (105) may a host controller operably coupled with a slave controller. The slave controller in turn may be coupled with a light regulator. Such an arrangement of the lighting control unit is beneficial considering the complexities of the arrangement in laminated glazing in a vehicle. The light regular is coupled with input power relay. The input power relay is configured to signal the light regulator. The light adjustment unit (106) may include a light detection sensor (like light dependent resistors, LDR or infrared, IR sensor) for sensing the light incident on the laminated structure. It might also include timer circuit to track the time of the day. The light adjustment unit (106) is coupled to communicate with lighting control unit (105).

In an implementation of the invention, brightness control may be based on 2 types of input: one input includes automatic brightness based on time of the day. Timer in the controller circuit detects the time of the day. Depending on the time of the day, for microLED backlight and array brightness depending on the time of the day based on timer circuit connected to the host controller. The other input type includes a light luminosity detection using LDR/ IR Sensor. The LDR Sensor and IR sensor near the display panel are connected to the host controller through CAN bus way to measure the ambient lighting and change of ambient lighting based on distance. LDR sensor is used to measure the Lux and IR Sensor to measure the distance. Host controller diagnostic with reference value table of required brightness and communication to slave controller. Slave controller calculated the required power to the regulator system and regulate power through PWM Signal. The communication between host controller and slave controller is through LIN. This has been depicted in FIG. 3B.

In an implementation of the present invention, a hysteresis based control methodology may be applied for auto-adjustment of the luminesce of the microLED modules or units. Based on application and the required commands, there may be one or more reference data created. The raw data is received by way of a serial communication means (serial for instance) from an ambient light sensor unit to a control unit or micro-controller or microprocessor. The received data is then decoded, for comparison of the actual value against the band of respective reference voltage in a pre-fed dataset (for instance and not limited to a reference table). Said pre-fed dataset consists of the expected LUX value for a given voltage, it further includes the minimum, average and the maximum values for reference for a given application. Depending on the required LUX value, the voltage is applied.

In an implementation of the present invention, the lighting control unit (105) operations may be sequentially done in four modes which is also provided in FIG. 3C. The modes being standby mode, diagnostics mode, regulator mode and driving mode. In a standby mode, the input parameters are attained by the light adjustment unit (106), in a diagnostics mode, the lighting control unit (105) determines whether the illumination is set to a desired value based on the obtained parameters, in a regulator mode, the lighting control unit adjusts the illumination of the light emissive unit to the desired value and in a driving mode, the light emissive unit displays at the desired value of illumination.

In an implementation of the present invention is disclosed the three different levels of brightness as brought by a display unit by controlling the resistance flow to the display driver unit. The light sensor is configured to calculate the irradiance value. For a specific scenario, the irradiance tends to increase from sunrise to noon and then decreases until sunset. Three different levels of brightness as brought by the display unit by controlling the resistance flow to the display driver unit. The light sensor will calculate the irradiance value. The irradiance will increase from sunrise until noon, and then decrease until sunset. Peak solar energy levels received tends to vary by latitude and season. In the following are details for an exemplary scenario tabulating the different parameters associated with luminosity values. FIG. 3D depicts a graphical form of the tabulated values.

Reference is made FIG. 4 A that discloses a method of incorporating a light emissive unit for display in the laminated structure according to an embodiment of the present invention. Said method comprises bending a flat substrate of glass or polymer as a first substrate of the laminated glass structure. The contact layers for enabling suitable fitting of the microLED unit on to the laminate structure is printed. The contact layers may be printed on flexible polymer substrate. In some case, the printing of the contact layers may also be done before binding the glass. The contact layers may be printed either by screen printing, inkjet, roll on roll process. The contact layers may be printed in glass of at least 0.7mm thick and contact layers can be printed to match the pixel structure of microLED modules such as and not limited to microLED chips. The specification of the contact layers is based on the array of microscopic LEDs of the light emissive unit. For instance, in case if we are having a 10x10 array size for the microscopic LEDs, the contact layer would also be having a similar specification capable of adopting the 10x10 array on to the laminated structure. The flexible array of microscopic LEDs is either printed on to the contact layer or are transferred for further bonding. The contact layer is bonded to the flexible array of microscopic LEDs. This bonding may be done by way of wire bonding. Once the stacked structure of the microLED is obtained on the substrate, suitable laminating process is followed for obtaining the display embedded laminated structure. The first substrate is then further processed with interlayer and second substrate for form shatter-proof structure with embedded display.

The array of microscopic LEDs of the light emissive unit may be customised for the embedding within the laminated structure, or alternatively, it may be obtained from the ones available. The formation of the array of microscopic LEDs of the light emissive unit may include growing gallium nitride, GaN, units on a flexible substrate. In an implementation of the invention, the flexible substrate is the interlayer of the laminated structure. For providing interconnections on said flexible substrate having GaN with an array of thin film transistors backplane, wherein the interconnections are via bonding layer. If the array of microscopic LEDs need to display coloured elements, then the phosphor quantum dots or colour filters are added to the array of thin film transistors backplane. Further to this, the flexible array of microscopic LEDs is formed by cutting the same. Printing the flexible array of microscopic LEDs on to the contact layer by pad printing, and including a transparent cushioning layer on the substrate which has the microLED for accommodating the profile or contours of the micro LED and absorbing direct pressure during printing. The cushioning layer is preferred to be over the LED layer.

The micro-emissive light array may be transferred directly to glass through roll to roll processing. The microLED modules or chips may be grown on semiconductor wafer. The thin film transistor backplane (such as and not limited to low- temperature polysilicon) for the LED chips are transferred to a donor substrate or on the interlayer. The microLED chips are picked and placed through roller coating on to the TFTs and are wire bonded. The method may include a next roll transfer to pick the donor substrate with both TFT and LED Chip onto a flexible backplane or glass. The glass or flexible substrate are printed with contact layers to make an active matrix microLED display. The contact layers in glass is then connected to the driving unit to control each pixel of microLED display. Further the LED chip may be coated with QDs to improve colour conversion over standard RGB microLEDs.

The contact layer may contain electronics that are much sensitive and needs to be protected. Reference is made to FIG. 4B, in which the cushioning layers protecting the electronics from the high pressure condition are depicted. FIG. 4B shows microLED stack assembled with a cushioning layer to avoid high stress on the micro elements. The cushion layer helps in accommodating the profile or contours of the micro LED and thereby helping in absorbing direct pressure over the electronics. The cushion layer may be transparent. It helps in avoiding the heat effects experienced through manufacturing process and also in real field environments where the effect of UV is also to be avoided. Reference is made to FIG. 4C that depicts microLED stack assembled with pad printing process on to the bent/ curved surface on glass. The electronics during printing needs to be handled with much precaution because the printing pressure condition may damage the LED panel. The printing of the complete panel or transferring the micro led from release layer to glazing can be done with the help of pad printing. The pad used is soft polymer based and thereby helps in accommodating the micro LEDs over the profile or contours glass layer and also helps in absorbing direct pressure over the electronics. The cushion layer is transparent. It helps in avoiding the heat effects experienced through manufacturing process and also in real field environments where the effect of UV is also to be avoided.

The disclosed solution targets at controlling the brightness of the display without compromising transparency of the display. One means of implementation may include adjusting the resistance spilt using a potentiometer that may be used by the LED module. On the other hand, the solution of the prior art (such as the ones disclosed in W02020226072A1 ) include changing the brightness by increasing the contrast of the backlight display. However, this may result in decreasing the luminosity of the entire module thereby affecting the transparency of the display. As a result, such solutions is in a way display correction rather than providing improvement of display brightness as offered by the present invention.

In an implementation of the present invention is disclosed the three different levels of brightness as brought by a display unit by controlling the resistance flow to the display driver unit. The light sensor is configured to calculate the irradiance value. For a specific scenario, the irradiance tends to increase from sunrise to noon and then decreases until sunset. Three different levels of brightness as brought by the display unit by controlling the resistance flow to the display driver unit. The light sensor will calculate the irradiance value. The irradiance will increase from sunrise until noon, and then decrease until sunset. Peak solar energy levels received tends to vary by latitude and season. In the following are details for an exemplary scenario tabulating the different parameters associated with luminosity values. FIG. 5A depicts a graphical form of the variation in direct radiation over a period of 24 hours for a given day.

Table 1

In an implementation of the present invention, reference is made to FIGs. 5B and 5C, where the one or more display units may be integrated with collimating reflectors either directly deposited on the display or on the interlayer (such as a PVB). The collimating reflectors may be assembled as a separate film over the display area. The other components of the display unit such as a bonding layer may be so chosen that it fits the process parameters of the making of the integrated display with microLED units. The melting point of the bonding layer may be so chosen that it is below 140°C with storage temperature compatibility of up to 125°C in some cases. A contact layer may be chosen from metallic or polymeric conductive material either in a form of a uniform coating or a grid structure. It would be appreciated by the skilled person that there may be more customization in terms of design, dimension, material and placement of layers so as to make it compatible with the lamination process and bring forth the required performance.

The display embedded laminated structure disclosed herein may be used for the same display for varied power. The same microLED can be used in either rear glass or side glass of the vehicle for multiple use with different display luminosity requirement. For example, emergency Stop Warning/ SOS may have higher brightness and icon indicator or gentle message can be with low brightness. The change in brightness may also be based on criticality of object. For instance, lesser bright collision warning icon display for driver may be used for an obstacle like stone and a brighter display may be used for a dog crossing and a further brighter display may be used for a commercial vehicle approaching. The identification of such objects before displaying may be performed by inputs from proximity sensor (for instance and not as limitation). With variations in only power of microLED messages can be conveyed via display to driver. For exampler, brighter display for vehicle close by with increasing luminosity of the light as the distance between vehicle decreases. Said micro light emissive unit may be embedded and assembled in other glazing structures which are not laminated and tempered with modifications. Assembly of this can be done through encapsulation as a tailor made child part in glass or as a stick on solution with a protective layer or cover to the atmosphere. The glass structure mentioned can be further processed to act as backplane. In this case glass to be used as substrate for TFT processing and depositing gate pattern to form TFT pattern. The microLED units will then be transferred directly on the glass through mass transfer or backplane. The glazing may be any of windshield, sidelite, quaterlite, backlite, sunroof, part of door of the vehicle and said vehicle is any of car, train or aircraft.

Some of the advantages of the present invention are enlisted in the following:

• In the disclosed laminated glazing with embedded display, the substrate layers are directly bonded with microLED displays for enabling customised microLED based display in laminated glazing of vehicle, in which the microLED structure is modified to accommodate into the laminated structure.

• The brightness of display of the laminated glazing can be controlled based on ambient light condition. It is possible to use the same embedded display unit for brighter and dimmer displays. The display unit may also serve as lighting elements for aesthetic purposes.

• The brightness of the display unit is varied by way of power control unit. Accordingly, the brightness around the display is not varied and to increase the display contrast. Hence, the transparency of the glazing is not affected by bringing variations in display brightness.

• The collimating reflectors on the substrate of the laminated glazing prevents back scattering or light and the formation of ghost image on the second surface of the glass or polymer substrate.

• The first or second substrate of the laminated structure includes coating with polarizing film to avoid display visibility from an opposite side of viewer or other side of BCP region.

Note that not all of the activities described above in the general description or the examples are required, that a portion of a specific activity may not be required, and that one or more further activities may be performed in addition to those described. Still further, the order in which activities are listed is not necessarily the order in which they are performed.

Benefits, other advantages, and solutions to problems have been described above with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any feature(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature of any or all the claims.

The specification and illustrations of the embodiments described herein are intended to provide a general understanding of the structure of the various embodiments. The specification and illustrations are not intended to serve as an exhaustive and comprehensive description of all of the elements and features of apparatus and systems that use the structures or methods described herein. Certain features, that are for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in a sub combination. Further, reference to values stated in ranges includes each and every value within that range. Many other embodiments may be apparent to skilled artisans only after reading this specification. Other embodiments may be used and derived from the disclosure, such that a structural substitution, logical substitution, or another change may be made without departing from the scope of the disclosure. Accordingly, the disclosure is to be regarded as illustrative rather than restrictive.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

List of reference numerals and the corresponding features of the same:

100: laminated structure 101: first substrate 102: one or more interlayers 103: second substrate 104: light emissive unit 105: the lighting control unit 106: light adjustment unit

107: a means for preventing formation of secondary images 211: abase substrate 212: a contact layer 213: a backplane 214: a bonding layer 220: flat connector

215: PN junction diodes 216: a protective layer 230 : LED driver unit 1001-1005: method steps

Claims

WE CLAIM

1. A laminated structure (100) for display in a vehicle, wherein said structure comprises: at least a first substrate (101), one or more interlayers (102) and at least a second substrate (103), wherein the first substrate and the second substrate are held together by the one or more interlayers therebetween; at least one light emissive unit (104) adapted for display in the laminated structure; wherein the at least one light emissive unit is adapted to be embedded between the first substrate and second substrate and said at least one light emissive unit (104) is operably coupled with at least one lighting control unit (105), wherein said lighting control unit (105) is outside the laminated structure; and a means (107) adapted for preventing formation of secondary images on surfaces the layers of the laminated structure; wherein the at least one lighting control unit (105) is configured to adjust the illumination of the at least one light emissive unit without affecting transparency of the laminated structure.

2. The laminated structure (100) as claimed in claim 1, wherein the at least one light emissive unit (105) comprises a micro light emitting diode (microLED) based display unit and the laminated structure is either flat or curved.

3. The laminated structure (100) as claimed in any one of the preceding claims, wherein the microLED based display unit comprises a stacked structure comprising a base substrate (211) adapted for including one or more array of microscopic light emitting diodes (LEDs) (215) capable of forming the individual display elements, and a LED driver unit (230) operably connected with the at least one lighting control unit (105) for controlled display in the laminated structure, wherein the LED driver unit is either within the laminated structure or outside the laminated structure.

4. The laminated structure (100) as claimed in any one of the preceding claims, wherein the at least one light emissive unit (105) further comprises: a backplane thin film transistor (213), TFT, adapted for accurate display of the elements; a bonding layer (214) adapted for bonding the one or more array of microscopic LEDs with the backplane TFT; and a contact layer (212) adapted for connecting the backplane TFT to the LED driver unit (230).

5. The laminated structure (100) as claimed in any one of the preceding claims, wherein the at least one light emissive unit (105) further comprises a protection layer (216) adapted to protect the light emissive unit from external factors including protection from ultra-violet radiations.

6. The laminated structure (100) as claimed in any one of the preceding claims, wherein the means (107) adapted for preventing formation of secondary images in the laminated structure includes a layer or coating of collimating reflectors to on the first substrate, or the second or the one or more interlayers.

7. The laminated structure (100) as claimed in any one of the preceding claims, wherein the first substrate or the second substrate or the one or more interlayers include coating with polarizing layer for selective view of the display.

8. The laminated structure (100) as claimed in any one of the preceding claims, wherein the structure further comprises a cushion layer adapted to accommodate the microLED and to absorb the direct pressure over the components thereon.

9. The laminated structure (100) as claimed in any one of the preceding claims, wherein the at least one lighting control unit (105) is configured to adjust the illumination of the light emissive unit based on the input from a light adjustment unit (106); wherein said light adjustment unit (106) is either in the laminated structure or outside the laminated structure.

10. The laminated structure (100) as claimed in any one of the preceding claims, wherein the at least one light emissive unit (104) includes a coated layer disposed around it adapted for heat dissipation.

11. The laminated structure (100) as claimed in any one of the preceding claims, wherein the light adjustment unit (106) comprises a light detection sensor for sensing the light incident on the laminated structure and/or a timer circuit to track the time of the day.

12. A system for display in glazing for a vehicle, wherein the system comprises: a glazing comprising at least one light emissive unit (104) including micro light emitting diode (microLED) disposed within the glazing and adapted for display in the glazing and a means (107) adapted for preventing formation of secondary images in the glazing; wherein the glazing is either laminated glazing or non-laminated glazing; at least one lighting control unit (105) operably coupled with said at least one light emissive unit (104) for adjusting the illumination of the at least one light emissive unit without affecting transparency of the glazing; and a control unit operably coupled to enable, disable and/or control the display in the glazing, wherein an electronic control unit of the vehicle is operably coupled with said control unit.

13. The system as claimed in claim 12, wherein the at least one light emissive unit (104) is configured to adjust the illumination of the at least one light emissive unit (105) based on inputs from a light adjustment unit (106) located within or outside the glazing and comprising a light detection sensor for sensing the light incident on the glazing and/or a timer circuit to track the time of the day and/or comprises one or more sub-modules configured to provide variation in the illumination of the light emissive unit (104).

14. The system as claimed in claim 12 or claim 13, wherein the at least one lighting control unit (105) is operable in a standby mode whereby the input parameters are attained by the light adjustment unit (106), a diagnostics mode whereby the lighting control unit (105) determines whether the illumination is set to a desired value based on the obtained parameters, a regulator mode whereby the lighting control unit adjusts the illumination of the light emissive unit to the desired value and a driving mode whereby the light emissive unit displays at the desired value of illumination.

15. A method of incorporating a light emissive unit for display in the laminated structure as claimed in claim 1, wherein the method comprises: bending (1001) a flat substrate of glass or polymer as a first substrate of the laminated structure; printing (1002) the contact layers on said substrate, wherein a specification of the contact layers is based on the array of microscopic LEDs of the light emissive unit; printing or transferring (1003) the flexible array of microscopic LEDs on to the contact layer; bonding (1004) the contact layer to the flexible array of microscopic LEDs via wire bonding; and laminating (1005) the first substrate with one or more interlayers and second substrate for form shatter-proof structure with embedded display.

16. The method as claim in claim 15, wherein the formation of the array of microscopic LEDs of the light emissive unit comprises: growing gallium nitride, GaN, units on a flexible substrate, wherein optionally the flexible substrate is the interlayer of the laminated structure; providing interconnections on said flexible substrate having GaN with an array of thin film transistors backplane, wherein the interconnections are via bonding layer; and optionally adding the phosphor quantum dots or colour filters to the array of thin film transistors backplane; and cutting the formed the flexible array of microscopic LEDs.

17. The method as claimed in claim 15, wherein printing the flexible array of microscopic LEDs on to the contact layer by pad printing, and including a transparent cushioning layer for accommodating the profile or contours of the micro LED and absorbing direct pressure during printing.