WO2023105534A1

WO2023105534A1 - A micro-electroluminescent display in glazing

Info

Publication number: WO2023105534A1
Application number: PCT/IN2022/051017
Authority: WO
Inventors: Arunvel Thangamani; Naveinah CHANDRASEKARAN
Original assignee: Saint-Gobain Glass France
Priority date: 2021-12-08
Filing date: 2022-11-22
Publication date: 2023-06-15

Abstract

Disclosed in the present invention is an automotive glazing (100) with a display for laminated and non-laminated glazing. The glazing comprises one or more electroluminescent display units (102) disposed on a substrate (101) of the glazing. Each of said electroluminescent display units comprises an array of plurality of micro-electroluminescent sub-units. The electroluminescent display units are configured to provide multiple independent display with varying and improved luminosities.

Description

A MICRO-ELECTROLUMINESCENT DISPLAY IN GLAZING

TECHNICAL FIELD

The present disclosure relates to display in automotive glazing, specifically, this disclosure relates to an automotive glazing with electroluminescent display unit having improved and varied luminosities. More specifically, this disclosure relates a solution of including micro-electroluminescent based display in the automotive glazing.

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 disclosure, or that any publication specifically or implicitly referenced is prior art.

Displays in automotive glazing finds a number of applications, both on the basis of functional aspects and also for aesthetics. The various applications of having display in automotive glazing includes and is not limited to aesthetic lighting, mood lighting, functional spot lighting, interactive lighting and the like. It adds value to the vehicle by enhancing its functionality and improving the user experience. Display units may be included in an automotive glazing either externally or internally. Such display devices may include light emitting diodes (LEDs), fluorescent displays, electroluminescent displays and the like. An electroluminescent display is generally made by covering both sides of an electroluminescent material (such as and not limited to phosphor) with conductors or conductive layers.

Reference is made to W02014009601A1 that discloses an inorganic, transparent thin film electroluminescent display element with a display area having at least one emissive area and at least one non-emissive area with improvements in terms of transparency and inconspicuousness is provided. In the therein disclosed solution, the emissive and non-emissive areas of the display are rendered optically similar by providing passive film elements at the non-emissive areas, by providing conductor material also at these areas when the conductive electrodes connected to a power source for generating the required voltage are deposited at the emissive areas. Although, the referred solution talks of having improved transparency in general, there are still scope of improving the transparency of electroluminescent display when it is embedded in automotive glazing.

A further reference is made to US20130099666A1 that discloses a light emitting display including a plurality of light emitting diodes or other type of light sources mounted in a parallel-connected array that is supplied electrical current from a power bus. The therein disclosed display unit includes plurality of resistive traces that extend between the power bus and the plurality of light sources. It further comprises a resistance of the plurality of resistive traces which is selectively controlled at least in part to compensate for a decreasing voltage along the power bus, so that each of the plurality of light sources is energized with a desired electrical current regardless of a distance from the proximal end of the power bus and positions where each of the plurality of light sources is connected to the power bus for achieving a desired level of luminosity. However, it is directed at including light emitting diode-based displays, and additionally this solution may not be suitable for specific automotive glazing which is essentially going to have a bent profile.

Another reference is made IN201741007887 that discloses a laminated glass for windshield of a vehicle comprising one or more electroluminescent devices that are connected to a connector element and provided within the glazing between one or more interlayers. The electroluminescent devices are connected to an electronic circuitry that enables display of luminous indicators and patterns on the windshield. However, we still need a better solution for display in automotive glazing having improved luminosity and/or varied luminosity. Often, for achieving improved luminosity or a variation in the luminosity of the display unit, external hardware may be used.

With the prior art solutions disclosed so far, there are still some challenges for varying the luminosity of an electroluminescent display unit or providing an improved luminosity of such display unit. Furthermore, it is desirable to have an automotive glazing with improved aesthetics as well. In view of the prior art disclosed hitherto, it is desirable to have an automotive glazing with display capable of providing improved luminosity and varied luminosity as well without having complex external hardware control on the display.

SUMMARY OF THE DISCLOSURE

An object of the present invention is to provide a display unit for automotive glazing overcoming the drawbacks of the prior art.

Another object of the present invention is to provide a display for automotive glazing with improved illumination.

Yet another object of the present invention is to provide a display unit with improved aesthetics and capable of varied applications.

A further object of the present invention is to provide a display unit in automotive glazing to reduce double image effect.

A still further object of the present invention is to provide an inconspicuous display unit (when not functioning) in automotive glazing. 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 an automotive glazing with a display. The glazing comprises one or more electroluminescent display units disposed on a substrate of the glazing, wherein each of said electroluminescent display units comprises an array of plurality of micro-electroluminescent sub-units wherein the electroluminescent display units are configured to provide multiple independent display units with varying and improved luminosities. The one or more conductive layers of the electroluminescent display units are made with varying trace width or with the same trace width for achieving series or parallel connection of the micro- electroluminescent sub-units and vary the luminosity across a design of the display unit. The display unit is sub-divided into multiple display areas or channels or micro- electroluminescent units to decrease load and increase luminosity. The display units may be used for lighting purpose or for display of input signal or data.

Technical benefits of the disclosed solution are to bring in customized output or desired effect on luminosity of the display panel by modifying or fabricating the trace width connectors. This is advantageous since the desired effect on luminosity could be achieved without having to work on the electronic hardware outside the glass assembly or glazing, which may require space, additional automotive testing etc. The disclosed solution also enables selectively activating portions of display unit to specifically convey a particular message. For this, group of micro-pixels or micro- electroluminescent units may be grouped together to form multiple display units and the functionality of the same could be controlled to pass voltage to selectively activate the display unit. This implies that if there are two or more display units, a user could selectively activate the display unit for achieving the desired output.

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 ACCOMPANYING 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.

FIG. 1 illustrates an example of the automotive glazing with a display according to an embodiment of the present invention.

FIG. 2 (a) -(b) illustrates a stacked structure of the micro-electroluminescent units based display in series and parallel connection respectively according to an embodiment of the present invention.

FIG. 3 (a) -(b) illustrates a schematic diagram of the micro-electroluminescent units based display in glazing, with said micro-electroluminescent units connected in series according to an embodiment of the present invention. FIG. 4 illustrates a schematic diagram of the micro-electroluminescent units based display in glazing, with said micro-electroluminescent units connected in parallel according to an embodiment of the present invention.

FIG. 5 (a) -(b) illustrates the display in non-laminated and laminated glazing according to an embodiment of the present invention.

FIG. 6 (a) illustrates an instance of tint matching feature according to an embodiment of the present invention.

FIG. 6 (b) illustrates an tint matching issue according to an embodiment of the present invention.

FIG. 7 illustrates method of manufacturing the automotive glazing with display 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.

DETAILED DESCRIPTION

The present disclosure is now discussed in more detail referring to the drawings that accompany the present application. It would be appreciated by a skilled person that this description to assist the understanding of the invention but these are to be regarded as merely exemplary. 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.

The present invention discloses micro-luminescent material for automotive glazing such as and not limited to laminated or bonded glazing. The micro-luminescent material based display in glazing disclosed herein includes design of micro- electroluminescent unit for improvised luminosity and to reduce double image effect through the bonding technique. The display device with varying energy carrying microlayers is capable of governing the luminosity level of the display. Generally, as the per the solutions known in the art, the inclusion of a display unit within the glazing may show tint variation in the glazing making it aesthetically unpleasant. Resolving this issue, the present invention provides a layer structure to at least decrease the tinted appearance of the display unit in the laminated glazing. Similarly, when display unit is embedded within the glazing, there may be issues of border of the unit being visible along the glazing unit. The present invention provides a solution for manufacturing of laminated display unit to avoid the border visibility around the edges. The disclosed solution is thus able to provide an inconspicuous display unit (when not functioning) in automotive glazing.

In an embodiment of the present invention is disclosed an automotive glazing (100) with a display as has been depicted in FIG. 1. This display may be used to show signal or data output to a user or may be used for simple lighting effect. Said automotive glazing comprises one or more electroluminescent display units (102) disposed on a substrate (101) of the glazing. Each of said electroluminescent display units comprises an array of plurality of micro-electroluminescent sub-units (121, 122, 123, 124, 125....) in which the electroluminescent display units are configured to provide multiple independent displays or lighting effect with varying and improved luminosities. The glazing (100) referred may be and not limited to laminated, non-laminated, or encapsulated glazing. It will include automotive glazing such as and not limited to windshields, backlite, sidelite, quarterlite, sunroof and the like. In some embodiments said display unit may be included in the pillar region as well. The glazing may have laminated, or tempered glass, however not limited to them. The electroluminescent material may be made or fabricated with varying or dynamic or same trace width to modulate the overall circuitry to the illuminating area to control and thereby vary the luminosity across the design of the display. The display units (102) may be embedded on any part or any side or at any location of the glazing. Traditionally, the automotive glazing includes black ceramic paint all around it for aesthetics and for solar protection for the adhesion of the glazing when being mounted to a vehicle. The display units may be embedded in such ceramic region as well, however not limited to this region. Embedding the display unit (102) in the ceramic region ensures solar protection for the unit. In an implementation of the invention, the power supply to the display unit (102) may be provided by means of bus bar (104). The display unit is configured to a driver unit for controlling said display unit. The driver unit may be connected to the display unit through one or more flexible connectors. The driver unit may be placed outside the glazing. The driver unit may be, for instance, a controller or a processor along with different ports or other connections specific to an application or use case, however not limited to these. Said driver unit is preferably placed outside the glazing and away from it. It may be used for controlling the inputs and signals to the display unit. In an implementation of the present invention, said driver unit may be a part of the electronic control unit of the vehicle or a separate entity and may be additionally attached with cruise control switch, lidar, radar, ultrasound sensors, camera or any vision systems, battery/ fuel level sensor etc., however not limited to these. In an embodiment of the present invention, the array of plurality of micro- electroluminescent sub-units of the electroluminescent display unit (102) are connected electrically in series connection or parallel connection. The display unit is disposed on one of the substrates (101) of the glazing. The electrical connection is so made that each of the micro-electroluminescent sub-units of the display unit (102) is provided with an optimal operating voltage to ensure a desired level of luminosity. The electroluminescent display unit (102) comprises a base substrate (1021) adapted for being disposed in the glazing and one or more conductive layers (1022) for providing voltage to the array of plurality of micro-electroluminescent sub-units. The base substrate (1021) of the display may be any of Polyethylene Terephthalate (PET), polyamide, or glass. However, the base substrate is not limited to these materials and is any material that may be adapted to be disposed on the substrate of the glazing. Said display unit (102) may optionally comprise one or more di-electric layers (1023) for improving the electrical strength of the display unit. The display unit further comprises the luminescent layer (1024) having the array of micro-electroluminescent sub-units. The luminescent layer (1024) is divided into sub- units of micro- electroluminescent channel to decrease the load and to increase the luminosity keeping the power supply constant. Reference may be made to FIG. 2 (a) that discloses the different layers that the electroluminescent display is composed of with same trace width and FIG. 2 (b) discloses the different layers of said display with varying trace width. The conductive layers (1022) and the optional di-electric layers (1023) is of varied thickness or same thickness across the substrate of the glazing. It is through the conductive layer that the voltage or power supply is provided. In an implementation of the present invention, the display region is provided the same voltage V and power P across its terminals by way of common bus bars (104a, 104b). In an implementation of the present invention, the conductive layers (1022) and the optional di-electric layers (1023) may be of varying thickness for series connection and same thickness for parallel connection. In an implementation of the present invention, the electroluminescent display unit may be organic or inorganic, transparent or non-transparent and is connected to a connector extending out of the glazing for further connection with driver unit or power source or so. Said connector may be transparent or non-transparent and is preferably flexible. Display element or unit may have a curved structure or a curved edge. The display element may have undergone a specific edge treatment like grinding laser smoothening and the like. In an implementation of the present invention, the electroluminescent display may be printed directly on the substrates of the glazing as well. The number of conductive layers, the di-electric layers and the luminescent layers are subjected to the application they intend to serve.

In an embodiment of the present invention, is disclosed that the conductive layer of the display unit may be varied in thickness by varying the trace width (105) of the channels, in the display unit, to control the power supplied to drive or trigger or activate a specific electroluminescent channel as is depicted in FIG. 3 (a) or FIG. 3 (b). This advantageously facilitates in designing a specific trace width that would give a required luminosity. In an implementation of the present invention, this may be achieved through depositing the specific trace width design by custom designed mask. This may also be achieved by way of precise control over phosphor and conductive element deposition and developing mask design in order to achieve the required trace width design during such deposition.

The series connection may be achieved by trace width variation of the current carrying conductive layer of the display unit. The display unit (102) is constructed to vary the energy carrying micro-layers that are factors for the luminosity level of a display and further varying the trace width to distribute multiple levels of voltage in serially connected emission material. A series connection may be achieved through distributed voltage. The series connection brings in customized effect on the display panel by custom fabricating the trace width connectors. The desired luminosity effect is thus advantageously achieved without having to work on any additional electronic hardware outside the glazing as seen in conventional cases. Further, the disclosed series connection of the micro-electroluminescent units is configured to selectively activate a portion of the display unit to specifically convey a particular display message or icon or pattern and the like. For the purpose, a group of micro- electroluminescent units or micro-pixels may be grouped into multiple display units and be controlled to pass voltage to selectively activate the display unit. It would be appreciated that the process of achieving the designated design as discussed is not a limitation, but it serves as an explanation to the skilled person. The different instances shown by FIG. 3 (a) and FIG. 3 (b) are two exemplary embodiments of the display in series connection. It would be appreciated by one skilled in the art that the different designs of enabling the series connections are dependent on the desired design or pattern of the display and is solely application dependent. The display unit may also be used for lighting purpose as well.

Reference is made to FIG. 4 that discloses a parallel connection of the one or more micro-electroluminescent units with distributed voltage. For parallel connection, the one or more conductive layers of the electroluminescent display units are fabricated with same trace width (105) for connection of the micro-elements of the electroluminescent material or micro- electroluminescent to modulate the electrical circuitry to the display area to provide same luminosity level across the design of the display unit. This facilitates in bringing about increased luminosity on the display panel by custom fabricating the trace width of connectors without having to work on any external hardware unit for bringing in the desired effect. To further illustrate this idea, consider a display of a specific icon and, say, said icon is divided into n-number of subpixels of micro-electroluminescent units. Such a connection may be applicable for use cases that require bright display and the same is achieved without varying the voltage or power parameters. Each of these micro-electroluminescent units is given the maximum voltage of up to say for instance 130 V of AC current. The disclosed embodiment of the present invention facilitates for ultimately having a minimal load for the voltage applied which will consequently increase the photon conversion efficiency of the display unit, thereby providing improved luminosity. Reference is made to FIGs. 3 and 4, where the conductive trace (105) in series connection of FIG. 3 (a) and FIG. 3 (b) shows variation in width while the conductive trace (105) of FIG. 4 is uniform.

In the disclosed embodiment, significant impact is attributed to the fabrication of the conductive trace width of the conductive layer of the display unit which includes masking which needs to be made with optimal micro-precision to divide these subpixels or micro-electroluminescent unit. Each of said units are small enough so that the gap between two sub micro-electroluminescent units is not visible to the naked eye yet not so small that they cause short circuiting between the pixels since each of them need to be powered independently. The series or parallel connection of the micro- electroluminescent display is configured to decrease the load, increase luminosity keeping the power supply constant.

In an embodiment of the present invention, the automotive glazing may comprise one or more metal coated substrates which are configured to function as the conductive layer of the electroluminescent unit. The metallic coatings (such as and not limited to silver coating) are selectively applied in the glazing for thermal management properties. In an implementation of the present invention such metal coated substrates may be masked, and laser etched to configure the series or parallel connection.

The automotive glazing in an embodiment of the present invention may have laminated glass. It comprises a first substrate (131a) of glass or polymer, a second substrate (131b) of glass or polymer and one or more interlayers (132a, 132b, 132c) sandwiching the first substrate (131a) and second substrate (131b) into a shatterproof laminated structure. The one or more electroluminescent display units (102) in such glazing may be disposed between the first and the second substrates (131a, 131b) as has been disclosed in FIG. 5 (a). In an implementation of the present invention, the glazing with said display unit (102) comprises one interlayer and the display unit is embedded in that interlayer. The glazing may comprise non-laminated glass assembly as well. In such cases the glazing material (glass or polymer) may be bonded with other material (such as another material of the glazing or polycarbonate). In an implementation of the invention, the bonding may be brought forth by using laser welding method. This will advantageously facilitate in reducing and even completely avoiding the production of double images or ghost images which is more prominent with multiple glass substrate layers in actual application. FIG. 5 (b) depicts an exemplary embodiment of the non-laminated glazing having the micro- electroluminescent display according to the present invention. The polymer or glass substrate (141) with the display may be laser bonded or bonded by way of laser sintering to another substrate of protective layer (142). In an implementation of the present invention is disclosed a possibility of reducing the overall glass thickness significantly from the traditional glass based glazing having thickness of 2.1 mm or 3 mm. The glass substrate may be laser welded or may be bonded by laser sintering in which one glass is the display panel itself and the other glass is the protective glass surface bonded together to make a glazing such as and not limited to quarterlite or such products. FIG. 5 (b) also depicts an example of one such laser bonding based glazing.

In an embodiment of the present invention is disclosed that glazing with the electroluminescent unit may be coated with multiple non-functional material to decrease the tint differentiation in the visible area of glazing. When display units are embedded in laminated glazing, although it may be a transparent display, there may be a tint difference between the display area and the remaining of the glazing structure. This is due to the coating on the material of the base substrate of the display unit which enables the display functionality. Visibility of the tint difference is aesthetically displeasing to the eyes. A possible solution may be to coat the functional material in the desired area and gradually decrease the tint towards the hue of the substrate of the glazing to give a visually pleasing effect. However, another possible solution as proposed in an embodiment of the present invention includes coating the display unit with multiple non-functional material to decrease the tint differentiation in the visible area of the glazing (aesthetics). Such coating of non-functional material on the display unit is relatively of low cost as compared to having a functional coating. Said nonfunctional coating includes any material that are added for the purpose of tint matching between region of the glazing having the display unit and the region of the glazing having no display. Such coatings are referred to as non-functional because as such they do not have a specific functionality but is included to reduce the obvious tint variation between the substrates of the glazing and the display unit. FIG. 6 (a) depicts a scenario where the tint variation as disclosed herein is shown and the FIG. 6 (b) depicts how it appears currently. Instances of such non-functional coatings may be SiCh and glass of varying thickness to alter the refractive index to not show the tint differentiation obviousness. In an implementation of the present invention is disclosed having a tint matched display embedded in glazing with ITO coating having at least 50% transparency, SiO2 coating having 60% transparency and the glass substrate having 70% transparency, thereby having a gradual tint matching aesthetically. FIG. 6 (a) shows an exemplary embodiment of the present invention having three levels of tint variation to make the display look inconspicuous by matching the tint of the display with the background hue of the glazing. Level 1 includes ITO coating and is of at least 50 % transparency, level 2 includes SiO2 of at least 60% transparency and level 3 is of 70% transparency. In the absence of such tint variation, as is the case in the prior art, the border is clearly visible. With this feature of gradual border degradation using nonfunctional material coating around the display advantageously provides tint variation and makes the display to appear inconspicuous.

In another embodiment of the present invention is disclosed a method of manufacturing the automotive glazing having laminated structure, which is also depicted in FIG. 7. The method comprises assembling (SI) a first and second substrate to one or more interlayers and further includes optionally making (S2) a cut-out on the interlayer. The cut-out in the interlayer may be made through etching, however not limited to this. The method further includes optional stamping (S3) of a second interlayer only in the cut-out region with higher temperature for defined time and pressure. Further to this, the display units are placed (S4) in the defined cut-out regions and a third interlayer is assembled. Third interlayer may or may not be an optional feature. The assembled layers are then de-aired (S5) to form a de-aired assembly and it is followed by autoclaving (S6) the de-aired assembly to form the laminated glazing with the electroluminescent units therein.

In a general scenario of making a laminated glazing, such as say a windshield, without any embedded elements said step of stamping is not required as the assembly is conventional with just two substrates of glasses and an interlayer. In an implementation of the present invention is provided a laminated glazing unit with the display panel and multiple interlayers such as PVBs. With multiple interlayers, there is always a challenge during the assembly because the interlayers do not stay in place and there may not be proper optical bonding just in the gap which may bring in some aesthetic issues in the final glazing. In order to avoid such issues, the step of local stamping has been proposed in an implementation of the present invention. Preferably, the interlayers are stamped during assembly process. This advantageously also reduces the issues of border visibility after lamination and enables proper multi-material bonding. In an implementation of the present invention, the cut-out in the interlayer is made to provide sufficient space for the display panel to locate itself in the laminated structure. However, this may again cause the border visibility issues due to the optical bonding mismatch between two materials and adversely affect the aesthetics of the glazing. Remedying, in the implementation of the present invention is disclosed that the glass substrate may first be assembled with a first interlayer (say PVB layer which is already stretched) and may further be assembled with a second interlayer (which is also stretched). The cut-out may now be made and further to which only the second interlayer is stamped in the cut-out region with higher temperature for a defined time and pressure. This ensures that the two interlayers do not move during the assembly or lamination process. This may be followed by placing the display material and assembling a third interlayer along with glass substrates.

Generally, in case if electroluminescent display units are to be embedded within the glazing with an intention of improved or variable luminosity, then each of the electroluminescent based display need to be provided with its own required voltage through power channels or lines to achieve the desired luminosity of the display. Said power channels or lines need to be disposed outside the display unit with the power being controlled by means of a drive transistor which needs to be connected to each electroluminescent display units. If a user desires of having display with a fading effect on the luminosity as shown in FIG. 3(a), then the construction of such a display with electroluminescent units having individual power control lines outside of the display will render it complex in construction. The solution of changing the trace width of the conductive or channels in the fabrication of the display unit itself (as depicted in FIGs. 3 (a) or 4) as per an embodiment of the present invention to achieve the desired effect of luminosity advantageously does not require complex physical construction to include power lines outside the display unit. In an implementation, the one or more conductive layers of the electroluminescent display units are fabricated with varying trace width or with the same trace width for achieving variation in luminosity across a design of the display unit. As has been depicted at least in FIGs. 2(a) and (b), the same operational voltage may be provided by the bus bar, however, the conductive layer of the display is varied to achieve the desired application specific design and luminosity. It can be used for display of contents, signal or data or for lighting purpose as well.

The automotive glazing with display as per the disclosed embodiment finds various applications to function as an output unit in which the display driver may be attached with cruise control switch, lidar, radar, ultrasound sensors, camera, battery/ fuel level sensor and the like. It may further find application in driver assistance display in the glazing with multiple luminosity, improvised experience of laminated display solution for a seamless embedding result.

Comparative example- 1

Arrangement: Two sample automotive glazing are taken: one with standard electroluminescent display unit and another one with micro-electroluminescent display unit. An input power supply of around 12 V DC is provided to an inverter and care must be taken to avoid input supply voltage to diverge much from 12 V DC. Further, connect the electroluminescent display load on output side for testing. Care must be taken to prevent reverse polarity on the input side and care must be taken to ensure that the supply connections are properly done. Direct contact with the AC output needs to be avoided for such display in the automotive glazing.

Principle for measurement of the luminosity: Conventionally, the amount of light emitted by a source at the surface is vital to determine the readability or luminosity of a display, rather than the light throw at specific distance. To determine the amount of light emitted by the display unit, generally the distance between the source and the detector must be at least 10 times the size of the source and the photo detector active area must be larger than the beam diameter. For instance, for a micro electroluminescent channel pixel of size 25 mm and the detector may be placed at a distance of 250 mm. Similarly, for an electroluminescent display pixel of size 50 mm, the detector can be placed at a distance of 500 mm. However, currently, the samples considered are all static icon and also due to the uneven lighting pattern, it is difficult to align the detector to the patterned surface. It is therefore, preferred to measure the luminosity at the surface and the perception value under day light conditions are observed. With no other light source and with such an arrangement it is possible to get measurement of the source. The sample details and the measured luminosity values are tabulated in the following:

It has been observed that the luminosity on surface offered by micro- electroluminescent display is improved as compared to standard electroluminescent display in automotive glazing. It has been observed that with varying trace width, the variation may also be bought in the luminosity of the display unit. Thus, with the present solution disclosed herein, both variation in luminosity and improvement in the luminosity can be brought forth. This is also achieved without the requirement of any external hardware device.

Some of the advantages of the present invention are provided as:

• The present invention provides improvised luminosity by breaking the luminous material composition to minute structures and provide operating voltage to each of the structure to achieve the highest luminosity. • The present invention provides a solution to reduce double image effect through the bonding technique.

• The layer structure as defined in the present invention is capable of avoiding or decreasing the tint appearance of the display in the laminated glazing.

• With the disclosed solution, there are no need of any additional doping elements to control the luminosity which may also affect the tinting of the glass substrate of the glazing which may add additional challenges to the transparent display applications.

List of reference numerals appearing in the accompanying drawings and the corresponding features: 100: automotive glazing 101: substrate of the glazing 102: display unit

121, 122, 123, 124, 125: micro-electroluminsecent unit

104a, 104b: Bus bar

105: conductive trace

1021 : base substrate of the display

1022: conductive Layer

1023 : Dielectric layer

131a, 131b: first and second substrate

132a, 132b, 132c: interlayers

140: laser bond

141: polymer or glass substrate in non-laminated glazing

142: protective layer in non-laminated glazing

S1-S6: steps of the method

Claims

WE CLAIM

1. An automotive glazing (100) with a display comprising: one or more electroluminescent display units (102) disposed on a substrate (101) of the glazing, wherein each of said electroluminescent display units comprises an array of plurality of micro-electroluminescent sub-units (121, 122, 123, 124, 125) wherein the electroluminescent display units are configured to provide multiple independent display with varying and improved luminosities.

2. The automotive glazing (100) as claimed in claim 1, wherein the electroluminescent display unit (102) further comprises a substrate adapted for being disposed in the glazing, one or more conductive layer for providing voltage to the array of plurality of micro- electroluminescent sub-units and optionally comprising one or more di-electric layers for improving the electrical strength of the display unit.

3. The automotive glazing (100) as claimed in claim 1 or claim 2, wherein the of micro- electroluminescent sub-units of the electroluminescent display units (102) are connected electrically in series connection or parallel connection such that each of the micro- electroluminescent sub-units is provided with an optimal operating voltage to ensure a desired level of luminosity.

4. The automotive glazing (100) as claimed in any one of the preceding claims 1-3, wherein the one or more conductive layers of the electroluminescent display units (102) are having varying trace width or the same trace width for achieving series or parallel connection of the micro-electroluminescent sub-units and vary the luminosity across a design of the display unit.

5. The automotive glazing (100) as claimed in any one of the preceding claims 1-4, wherein the optional di-electric layer is of varied thickness or same thickness across the substrate of the glazing.

6. The automotive glazing (100) as claimed in any one of the preceding claims 1-5, wherein the conductive trace for providing voltage to the array of plurality of micro- electroluminescent sub-units is configured as thin film transistors (TFT) transistors as switching element to control the display.

7. The automotive glazing (100) as claimed in any one of the preceding claims 1-6, wherein the glazing comprises a first substrate of glass or polymer, a second substrate of glass or polymer and one or more interlayers sandwiching the first and second substrate into a laminated glazing; wherein the one or more electroluminescent display units (102) are disposed between the first and the second substrates.

8. The automotive glazing (100) as claimed in any one of the preceding claims 1-7, wherein the glazing comprises a first substrate of glass or polymer, a second substrate of glass or polymer such that the first substrate of glass or polymer and the second substrate of glass or polymer are bonded together by a bonding layer wherein said bonding layer is formed by way of laser sintering.

9. The automotive glazing (100) as claimed in any one of the preceding claims 1-8, wherein the glazing comprises one or more metal coated substrates configured to function as the conductive layer of the electroluminescent unit.

10. The automotive glazing (100) as claimed in any one of the preceding claims 1-9, wherein the electroluminescent unit is coated with multiple non-functional materials to decrease the tint differentiation in a visible area of glazing.

11. The automotive glazing (100) as claimed in any one of the preceding claims 1-10, wherein the display unit is configured to a driver unit through either one or multiple flexible connectors for controlling the display unit, wherein said driver unit is placed outside the glazing.

12. A method of manufacturing the automotive glazing (100) as claimed in any one of the preceding claims 1-11, wherein the method comprises: assembling (SI) a first and second substrate to one or more interlayers; optionally making (S2) one or more cut-outs on the one or more interlayers wherein said cut-out is made optionally through etching; optionally stamping (S3) a second interlayer only in the cut-out region with higher temperature for defined time and pressure; placing (S4) the display units in the defined cut-out regions; optionally assembling a third interlayer; de-airing (S5) the assembly to form a de-aired assembly; and autoclaving (S6) the de-aired assembly to form the laminated glazing with the electroluminescent units therein.