BE1026226A1 - REAL-TIME FORMAT AND TRANSPARENT DISPLAY - Google Patents

Abstract

The invention relates to a deformable display, more particularly a flexible, stretchable and transparent deformable display based on light-emitting elements such as, for example, light-emitting diodes (LEDs). The invention also relates to the use and applications of such a deformable display, including systems and methods that use such a deformable display. In addition, the invention relates to a flexible, stretchable and transparent display that is deformable in real time while maintaining the deformability.

Description

REAL-TIME DEFORMABLE AND TRANSPARENT DISPLAY

Technical field

The invention relates to a deformable display, more particularly the invention relates to a flexible, stretchable and transparent deformable display that uses or is based on light-emitting elements such as, for example, light-emitting diodes (LEDs). The invention also relates to the use and applications of such a deformable display, including systems and methods that use such a deformable display. In addition, the invention relates to a flexible, stretchable and transparent display that is deformable in real time while maintaining the deformability.

BACKGROUND OF THE INVENTION

Transparent displays, such as LCD and OLED screens as currently known, typically use indium tin oxide layer (ITO) as thin films with optical transparency and comprising electrically conductive material. The high resistivity of such ITO layers, however, allows very little current to be transferred, and therefore results in very slow reacting or switching circuits. As a result, transparent displays from the art are not really suitable for video applications.

State-of-the-art flexible displays either represent a one-off flexibility or remain flexible, although such flexibility is always somehow limited. This last flexible display, which remains flexible, can usually be seen as a combination of several small rigid bodies that are movably connected to each other or are hinged to each other. Due to this partially movable configuration, the flexing of such flexible screens is limited. In the case of one-off flexibility, the flexible display is bent and then usually held in a certain shape. The shape or shape is therefore generally defined during installation. It is further noted that the majority of such a one-off flexibility display is not transparent because several components must generate the flexibility (and therefore have to focus on it). In fact, the flexing of flexibly printable displays (for example, possibly OLED displays) is limited to a single direction or cardinal, and therefore multiple flexing or distortion of the flex display sheet is

BE2019 / 5196 subject to wear, defective connections or even broken components or connection parts. In other words, current flexible screens represent an interesting technical problem with only limited flexibility and represent the need to improve the robustness of the screen due to its frequent bending or distortion use.

Existing stretchable electronics are generally based on serpentine circuits, or meander geometry of interconnections as used, for example, in smartphone displays, or in a broader sense, using a folded or semi-curved electronic link to adaptively enlarge (and then be able to reduce again) ) and hence stretching (and later being able to recompress) the distance between the electronic components. Stretchable electronics thus means that more material, i.e. longer distance or connection, is used to make the interconnections such that the stretching functionality can be performed. But more material also means that there is less space available between the electronic components, such as LEDs, for creating a higher resolution. Therefore, the use of known stretchable electronic technology limits the required resolution for a display application, as we would often expect for a non-stretchable standard display system.

Object of the invention

The object of the invention is to provide a real-time formable and transparent display or pixel (addressed) device in general, which retains its formable character at any time, such as being able to bend and stretch, for example. More in particular, the object of the invention is to provide a real-time, deformable and transparent display capable of displaying high-resolution video images.

Summary of the invention

In a first aspect of the invention, a method is provided for manufacturing a deformable display (or display), the method comprising providing a printed circuit board and providing an arrangement of pixels on the printed circuit board. The method also includes providing connections on the circuit board to provide power to the pixels and / or to connect two or more pixels to each other, preferably between two or more pixels.

BE2019 / 5196 at least one data connection from one pixel to the other. By deformable display is meant, for example, that the display can be bent or rolled up, or brought into a different shape or shape, or even stretched. The method further comprises selectively, i.e. selectively, removing a substantial portion of the printed circuit board in the areas where none of the pixels or connections between them are present, such that a degree of transparency is achieved and such that remaining portion of the printed circuit board becomes deformable, while the deformability is retained. The method may include providing a drive module at each individual pixel for controlling the pixels at the individual pixel level. According to an embodiment, the method comprises providing an arrangement of functional nodes (or nodes) in between the arrangement of pixels, the functional nodes being connected to the pixels, the pixels being, for example, light-emitting elements, such as light-emitting diodes (LEDs) and wherein the functional nodes are, for example, photovoltaic (PV) cells, whether or not provided with storage capacity, accelerators, gyroscopes, sensors, microphones / speakers, piezo elements, ultrasonic components, light-emitting elements. The method may further comprise providing a thermoplastic material wherein the pixels connected to each other are embedded pixels, the thermoplastic material being, for example, transparent. The thermoplastic material may be provided with perforations and / or hardened parts, and / or connecting parts, and / or mechanical adaptations or appendages, either globally for the entire device, or otherwise applied locally. Moreover, the thermoplastic material can be provided with fire-retardant material and / or with acoustically permeable material and / or sound-absorbing material, and / or optical components such as, for example, lenses, diffusers or polarizers.

In a second aspect of the invention, a deformable display system is provided that includes a plurality of printed circuit boards and an arrangement of pixels on the plurality of printed circuit boards, such that at least a portion of the plurality of printed circuit boards have one or more of the pixels mounted thereon, and such that the pixels are connected to each other. Within the deformable display system, connections are provided between the pixels, i.e. on printed circuit board material, while the pixels are mounted thereon, or directly on the printed circuit boards. Such connections are intended to supply power to the pixels and / or to connect two or more pixels together. Preferably, at least one data connection from one pixel to the other is provided between two or more pixels. The arrangement of pixels on the number of printed circuit boards, including connections between them, works

BE2019 / 5196 as a mesh net-like carrier that is deformable at any time in any direction, without losing its deformability. The malleable display system may include a drive module for each individual pixel mounted on the printed circuit board material for controlling the individual pixel. The pixels can be light-emitting elements, such as, for example, light-emitting diodes (LEDs), such that the malleable display system is a light-emitting display system, such as, for example, an LED display system. The printed circuit boards can be flexible printed circuit boards and / or the pixels can be connected to each other by means of conductive paths, for example stretchable conductive paths, e.g. made from copper.

In a third aspect of the invention, a color calibration method is provided, wherein the method (or method) is performed by a processing system of a display system that includes a storage module. By way of example, the display system may be a deformable display system in accordance with the second aspect of the invention. The method consists of the following steps. A first set of color points is defined, wherein at least one color, for example blue, is in the minority, and a second set of color points is defined, the at least one color, e.g. blue, for example, is in the majority. Next, a matrix formula is defined in which colors to be added to the first or second set of color points are calculated to determine target colors for the first or second set of color points. Target colors are defined as the colors to be observed on the display system. A first calibration matrix is then defined by the matrix formula for the first set of color points and a second calibration matrix is defined by the matrix formula for the second set of color points. A matrix factor, being selectively selected in relation to the at least one color, e.g. blue, being in the minority or majority of the first or second set of color points and thus the perception thereof as small or important, is defined as a real number between 0 and 1. A final calibration matrix is defined by the first and second calibration matrix, where both are weighted based on the matrix factor.

In a fourth aspect of the invention, a color calibration method is provided for calibrating a display system with respect to color points for a specific viewing angle. Depending on the viewing angle at which one looks at the display system, colors can be perceived quite differently. By way of example, again the display system may be a deformable display system in accordance with the second aspect of the invention. The

BE2019 / 5196 method performed by a processing system of a display system comprising a storage module comprises the following steps. A first set of color points is defined for a first viewing angle, a second set of color points is defined for a second viewing angle and a third set of color points is defined for a third viewing angle. A matrix formula is then defined in which colors to be added to the first, second or third set of color points are calculated to achieve target colors for the first, second or third set of color points. Three calibration matrices are then defined. A first calibration matrix is defined by the matrix formula for the first set of color points, while a second calibration matrix is defined by the matrix formula for the second set of color points and a third calibration matrix is defined by the matrix formula for the third set of color points. A matrix factor, which is selectively selected in relation to first, second, and third viewing angle color points, is defined as a real number between 0 and 1. A final calibration matrix is defined by the first, second, and third calibration matrix, each of which is weighted based on the matrix factor .

In a fifth aspect of the invention, a color calibration method is provided for calibrating a display system depending on a display characteristic associated with color. Depending on the specifications, characteristics or variable parameters of such a display feature, colors can be interpreted quite differently. The perceived colors can be influenced, for example, by the temperature or the amount of current flowing through light-emitting elements such as LEDs of the display system. By way of example, again the display system may be a deformable display system in accordance with the second aspect of the invention. The method performed by a processing system of a display system comprising a storage module comprises the following steps. A first to nth - n being an integer - series of color points is defined for a first to nth display characteristic with respect to color, respectively. A matrix formula is defined in which colors to be added to the first to nth series of color points are calculated to achieve target colors for the first to nth series of color points. Next, n calibration matrices are defined in which the first to nth calibration matrix, respectively, is defined by the matrix formula for the first to nth series of color points. A matrix factor, which is selectively selected in relation to the first to nth display characteristics with respect to color, is defined as a real

BE2019 / 5196 number between 0 and 1. A final calibration matrix is defined by the first to nth calibration matrix, each of which is weighted based on the matrix factor.

The color calibration method according to the third, fourth or fifth aspect of the invention can be applied to a deformable display system in accordance with the second aspect of the invention.

According to another aspect of the invention, a run-time color calibration method is provided by a display system processing system that includes a storage module, the method comprising: (i) loading operational conditions, e.g. with respect to at least one color, for example blue, which is in the minority or majority of the display system, (ii) calculation, possibly in real time, of a final calibration matrix, based on the operational conditions, by combining or weighing from first and second or first, second and third, or alternatively first to nth calibration matrix, as determined, for example, by the methods according to the third, fourth or fifth aspect of the invention, respectively, and thus these numbered calibration matrices relate to the determination of target colors to be achieved, more particularly in connection with 'what to add' or to add colors to the existing colors for achieving the target colors, while these numbered calibration matrices, i.e. first, second ... to n- the calibration matrix is retrieved for storage in the storage module; and (iii) applying the calculated final calibration matrix. By way of example, again the display system may be a deformable display system in accordance with the second aspect of the invention.

According to an aspect of the invention, a computer program product is provided, operable on a processing machine, for performing one of the steps of the methods in accordance with third, fourth or fifth aspect of the invention. According to an additional aspect of the invention, a non-temporary machine-readable storage medium stores the computer program product in accordance with the above.

According to an aspect of the invention, a real-time deformable and transparent pixel-addressed device is provided, comprising a support comprising a printed circuit board and conductive paths mounted thereon, and an array of pixels mounted on the support, the pixels being connected to each other by by means of the conductive paths, wherein the printed circuit board is partially removed from the support, defining a mesh net shape with transparency for the support with open spaces between the conductive paths and the pixels, and wherein

BE2019 / 5196 the mesh-meshed carrier with transparency can be deformed at any time in any direction without losing its deformability. By pixel-addressed device is meant a device (e.g., a display but also, for example, a lamp or a light-emitting device can generally be interpreted) wherein one or more individual pixels or one or more clusters of pixels of different data can be given , such as color data. A cluster of pixels can be represented as a whole as if it is only one pixel, or as being interpreted as a single pixel. In other words, the cluster appears as a whole.

According to an aspect of the invention, a calibration technique is provided for a pixel-addressed device, for example, a real-time deformable and transparent pixel-addressed device in accordance with the preceding aspect above. With this calibration technique, more particularly a color calibration technique, the colors of the pixels within the pixel-addressed device can be dynamically adjusted real-time depending on the content of the video or images, creating the impression that much deeper saturated colors can be seen.

Overview of the drawings

Figure 1 shows the aspect of multiplexing within a display matrix, here for example for an OLED display, in accordance with the state of the art.

Figure 2 shows an embodiment of the control signal generated in various ways in accordance with the invention, wherein in (a) each LED or pixel node is sequentially connected, while in (b) there is only a single control line for all LEDs or pixels.

Figure 3 shows an embodiment of local control or local interface for enabling modularity within a display system, in accordance with the invention.

Figure 4 illustrates a chromaticity diagram also known as the color space CIE 1931. Figure 5 schematically illustrates an embodiment of different types of display images, from (a) fixed to (b) deformable, to (c) real-time deformable image, for which calibration can be done be used in accordance with the invention.

Figure 6 shows an embodiment of a real-time malleable and transparent pixel-addressed device in accordance with the invention.

BE2019 / 5196

Figure 7 illustrates a viewing angle graph of an exemplary LED in accordance with the art.

Description of the invention

The invention provides a real-time deformable and transparent pixel-addressed device, such as a display (or screen), or more particularly, for example, an LED display, which retains its deformable character at any time, for example in that it is capable of e.g. to bend and stretch. The invention furthermore provides a real-time deformable and transparent display that can display high-resolution video images. With real-time deformable display is meant that the display can be deformed directly or immediately upon request, or as desired by a user of the display. In addition, the display is malleable while maintaining the malleability. In other words, the display can be distorted with reversibility, which means that the display can not only be distorted but is also able to return to an original state or an earlier status or shape.

The invention relates to a solution to the problems or disadvantages as stated in the background of the invention described above. The way in which one of these problems was addressed, solutions came about and ultimately how all parts of the invention were accomplished will now be described.

As mentioned earlier, current transparent displays, for example based on LCD or OLED with an acceptable resolution, due to their high-resistance ITO layers, are not really suitable for video applications. A solution could be to add more metal to the display structure to improve the conductivity and reduce the resistance, but this would also mean that the transparency decreases. The use of more metal would further result in a kind of mirror effect due to the reflections of the added metal. Moreover, such a solution would considerably complicate the production process.

Although there is a transparent LED display that avoids ITO layers and their negative impact on video applications, the resolution of such an LED screen is so poor that it cannot be taken into account, because it is not possible to compare it. made. As an indication for this low resolution, for example, the pixel pitch is in the range of> 8 mm. In addition, standard LED displays all have rather heavy and bulky equipment, including, for example, the mechanical carriers, PCB boards with components and

BE2019 / 5196 driver chips. A lightweight, transparent, high resolution LED display solution is not available in the art.

Lightweight high resolution display solutions can be found under the flexible displays. However, as described above, known flexible displays are usually limited in bending or deforming, have only flexibility in a single direction and are therefore very subject to wear, defective connections or even broken components or connecting parts.

Adding more flexibility in multiple directions instead of for example one or two orthogonals can be achieved with stretchable electronics, although on the other hand this results in more material and therefore less space available for making a high-resolution application. A possible solution for this lack of space, in the case of an LED display for example, provides the LEDs (e.g. RGB LEDs) in a grid or matrix structure while being assembled on a multi-layer PCB that ensures all connections and interconnections from anode to cathode . Reducing the number of connections can also be achieved by multiplexing connections within the circuit. Multiplexing, a known technique in the display industry, is often referred to as scanning, while rows or matrices are scanned one by one and the required LEDs are sequentially illuminated only in one row or array at a time. Either way, by means of stretchable electronics, and in particular the layout of the circuit and the display architecture, a high resolution display solution is still available. The high resolution display can now be made transparent, for example by removing unused or uncovered PCBs between the electronic circuit components and interconnections. To make a transparent high-resolution display flexible, the PCB used (either single layer or multi-layer) is not a standard epoxy but instead a flexible PCB is provided with the electronic circuit including stretchable electronics to provide greater flexibility than regular flexible screens with standard limited formability. In accordance with the invention, a transparent, stretchable and high-resolution display is provided characterized by being deformable, and furthermore, this deformability can be real-time while preserving deformability. In one embodiment, the stretchable electronics covering a flexible PCB include meander paths, e.g. made of copper, between rigid or rigid electronic components that, for example, represent the nodes where light-emitting diodes (LEDs) or light-emitting elements can generally be

BE2019 / 5196 mounted. In order to achieve transparency, the flexible PCB material that is not covered with stretchable electronics, nor with any other electronics, and thus uncovered or unused flexible PCB material that has no electronic functionality, can be removed, for example by means of laser, punching, water jet, milling or another possible abrasive process.

The aspect of multiplexing as a possible solution for reducing the number of connections within a circuit is now further considered, with reference to Figure 1, which illustrates multiplexing within a display matrix - an OLED display is shown here by way of example - as is known in the art. . Traditional LEDs in display applications are usually driven by means of a passive matrix structure, thereby referring to, for example, the common anode principle, although common cathode is also a possibility. Applying multiplexing within the passive matrix LED display will result in many connections. For example, if a rectangular LED display is considered, multiplexed strongly and efficiently, only one of the four display sides is e.g. provided with an enormous amount of connections, especially in the case of a high-resolution configuration. Such an enormous amount of connections causes difficulties and is in fact undesirable. In accordance with the invention, a solution is provided to address this problem and therefore to reduce the number of connections between the pixel nodes of a light-emitting display. According to an embodiment, at each of the pixel nodes where an LED is mounted, a local pixel driver or LED driver is provided for each individual pixel or LED. Consequently, only one LED voltage and a control signal are provided per pixel node or per LED node, and three connections (e.g. Vled, GND and a - possibly digital - signal) are sufficient per LED or pixel node for such voltage and control signal. The control signal at a certain LED will communicate with the LED driver via a protocol (for example on driver IC or electronics) how much light has to be emitted by this LED. In general, a large amount of similar or identical LEDs are used in display applications, and therefore similar or identical LEDs are used over a certain display surface, and therefore (the same) LED voltage can be applied to each individual LED or pixel node. A considerable number of multiplex connections has not yet been eliminated. The control signal, possibly digital, can be generated in various ways, as illustrated in Figure 2. A first option is, for example, NeoPixel, the Adafruit brand for individually addressable RGB color pixels and strips based on the WS2812, WS2811

BE2019 / 5196 and SK6812 LED / drivers, using a single-wire control protocol. Traditionally use is made here of an input and output signal in which each node is connected in succession, as schematically shown in Figure 2 (a) in which a node 202 as well as the sequential control signal as input 201 and as output 203 are illustrated. With this configuration, the position of an LED in the grid can be determined by sending certain information or data (data), for which reference can further be made to datasheets of the LED drivers. Alternatively, unlike the NeoPixel principle, each driver IC has a unique address, so that the control signal no longer needs to be sent via input / output but can be presented at each individual pixel node, each driven by an individual LED driver . Hence, for the other option, only a single control signal or control line is required for all LEDs or pixels, as shown in Figure 2 (b) where a pixel node 206 and the control line 204 including a branch 205 thereof are shown to the respective pixel node 206. As a result, routing becomes much easier and moreover, some sort of redundancy is provided, while in the event that the control signal is interrupted somewhere, the rest of the circuit can remain active. For both ways of generating the control signal, the advantage is that, for example, a square or rectangular (or other polygonal) screen can be cut into any shape without loss of video or image. However, in the case of the alternative option (as opposed to the one based on the NeoPixel principle) for generating the control signal, the potential in random forms is quite unlimited, while for the other control signal configuration the number of possibilities is limited due to the sequential line or circuit.

It is noted that the LED driver or pixel driver could be a TFT circuit or a traditional silicon-based driver.

As mentioned above, according to an embodiment of the invention, a local driver system is provided for each individual pixel or LED, resulting in much fewer connections required compared to traditional multiplex systems, which means that multi-layer PCBs or multi-layer flexible (or flex) PCBs are required . With the local driver system, cheaper display systems can therefore be offered due to a considerable reduction in the number of (flex) PCB layers, although the extra costs of the individual LED or pixel drivers are taken into account. On the other hand, instead of cheaper systems,

BE2019 / 5196, more efficient and better performing multi-layer systems can be offered with extra redundancy. For example, further utilizing the multilayer architecture, not just one LED voltage Vled, but a number of LED voltages Vledi, V _L ed2 ... Vledr connected in parallel, could be supplied for 1, 2 ... n layers ( flex) PCB material. If, for example, a V _L EDi line or circuit fails, the other V _L ed2 ... V _L EDn lines still remain usable. Moreover, if such a plurality of parallel connected LED voltages Vledi, V _L ed2 ... V _L ED n is provided for a specific circuit part, instead of only one Vled voltage line, the total resistance of this specific circuit part will decrease, causing the current will increase, and thus the efficiency of the LED display will improve. Referring further to the multi-layer configuration, having more Vledi, V _L ed2 ... Vledr lines results in more cutting options for reforming and / or (re) designing on the basis of arbitrary shapes. Moreover, with the local driver system and pixel node addressing, in addition to more cutting options, more paste options are also feasible. In other words, there is more freedom or flexibility and there are more ways to assemble screens seamlessly or to display display segments. A modular system 301, 304 can therefore be built, as illustrated by way of example in Figure 3. Multiple display segments 302, 305 can be seamlessly merged and are each provided with a local control 303, 306 or local interface. Figure 3 (a) and Figure 3 (b) illustrate a difference in display segment design, respectively, in terms of location chosen to provide local control 303, 306. In Figure 3 (a), local control 303 is positioned for each display segment 302 in the upper left corner of each display segment 302, while in Figure 3 (b) the local control 306 for each display segment 305 is positioned in the center of each display segment 305. The applicability and use of the local control 303, 306 is a result of, in the first place with a local pixel driver or local LED driver for each individual pixel or LED, and consequently applying only a single control signal or control line for all LEDs or pixels.

Because now far fewer connections are needed with the local driver system, more technical space is available to provide extra nodes between the existing LED or pixel nodes with the LED matrix, and thus to offer extra functionality. For example, photovoltaic (PV) cells can be mounted or assembled at the additional nodes, and therefore a power system can be integrated into the display application. The PV system can further be an integrated battery solution or

BE2019 / 5196 storage device. A standalone display system can therefore be offered without the need for an additional external power supply or a wired connection to the electricity grid. The additional nodes can also be provided with infrared light-emitting elements, or so-called active markers that are used in an optical tracking system. Via selective camera systems, the infrared light, which is invisible and has a safe intensity for the human eye, can act as feedback to source images that make it possible to compensate for geometric distortion of a screen. Furthermore, resistive or capacitive nodes can be integrated to provide interaction with the display, such as, for example, touch sensors for a touch screen. In addition to any additional functionalities for the aforementioned additional nodes, one can also refer to other well-known internet-of-things (loT) applications, including e.g. gyroscope, accelerator pedal, microphone / loudspeaker, piezo elements, ultrasonic components and sensors such as, for example, motion sensors.

Figure 4 illustrates a chromaticity diagram, in particular the CIE 1931 color space, which is provided as a reference for the discussion regarding real-time positional and content-dependent calibration for the currently described real-time deformable and transparent pixel-addressed device. . Since many different LEDs are used, it is known from the art that calibration of the LEDs is an important aspect, while each individual LED may differ in color, brightness, etc. The calibration principle around light-emitting elements (e.g. LEDs, OLEDs) or Making pixels look uniform on a screen is common, as is the math behind it. This principle is based on individual measurements at a given drive current for each pixel in the display. In the case of an RGB (red, green, blue) screen, the measurements are e.g. executed in the color space CIE 1931, in which each color is represented in (x, y) and Y, for example:

Rin = (Rinx, Riny, RinY) = (RinX, RinY, RinZ)

Gin = (Ginx, Giny, GinY) = (GinX, GinY, GinZ)

Bin = (Binx, Biny, BinY) = (BinX, BinY, BinZ)

It is noted that (x, y) are normalized values of X, Y and Z being the so-called tristimulus values, while Y is a measure of the luminance of a color.

As mentioned, there is a deviation in color and light output for all LEDs or pixels. After analyzing these deviations, a 'common' goal can be set for the individual colors. In general, this common denominator is the value of the light output and color that each LED or

BE2019 / 5196 pixel. For the sake of clarity, target colors are defined here. In the case of it

RGB display therefore determines three target colors: Rtarg, Gtarg and Btarg, where, for example, for the color red:

Rtarg = (Rtargx, Rtargy, RtargY) = (RtargX, RtargY, RtargZ) and

RtargX = RinX. RonR + GinX. GonR + BinX. BonR

RtargY = RinY. RonR + GinY. GonR + BinY. BonR

RtargZ = RinZ. RonR + GinZ. GonR + BinZ. BonR

Herein, RonR is the factor required for the red color individually, while GonR indicates how much green is to be added and BonR is the amount of blue to be added to red, so that the desired new red target color can be achieved.

In matrix format this leads to the comparison:

RonR RinX GinX BinX -1 RtargX GonR = RinY GinY BinY RtargY BonR. RinZ GinZ BinZ. RtargZ.

Or for all three colors we have:

RonR RonG RonB RinX GinX BinX -1 "RtargX GtargX BtargX GonR Gong GonB = RinY GinY BinY RtargY GtargY BtargY BonR BonG BonB. RinZ GinZ BinZ. .RtargZ GtargZ BtargZ.

According to an aspect of the invention, when applying the calibration principle, it is not necessary to make the entire set of parameters positive, moreover it may even be preferable to achieve better color saturation in the individual colors. Negative coefficients are therefore permitted and can generally produce the correct mixed color, especially when white is considered. Negative coefficients mean that the individual color cannot be calibrated (with corresponding calculations) to the saturated target color. However, when negative coefficients are always taken into account, they remain present and may still have an effect when mixing other input colors, thereby retaining the desired color when mixed. When negative coefficients are allowed, deeper or more saturated colors can be displayed, or virtual deeper colors are taken into account for the calibration calculations.

The above calibration principle works fine, but there is a serious error in the ClE definition of colors. This standard was made long ago when monochromatic light sources or narrow-band emitters, such as LEDs, did not exist. The chromaticity diagram does not hold any more

BE2019 / 5196 takes into account brightness differences in colors. In addition, a well-known problem is that when narrow-band emitters are mixed together, the color perception of the mixed color can be entirely different from what is measured with, for example, a spectrometer. Two colors with exactly the same reading on the spectrometer could be perceived completely differently by the human eye due to e.g. mixing narrowband emitters and / or not considering the brightness. This is in particular the case when, for example, the blue color is calibrated and is shifted to a less saturated blue color. The mixing ratio (addition of red and green color) to the native blue can have completely different visual effects. The human eye or brain locks the most perceived 'sharp' color (usually red), whereby the other colors with a less sharp perception (such as blue) are completely omitted. Thus, although - as according to CIE 1931 - colors measure exactly the same, they are perceived completely differently by the human eye. It is also well known in the display industry that less bright colors are considered more saturated, i.e., deeper, meaning closer to the edge of the ClE curve. With reference to both the mixing of narrow-band emitters and brightness problems above, it is perfectly possible, for example, to adjust two different blue colors by, for example, changing the brightness of the less saturated color, i.e., making its perception deeper. For example, by reducing the brightness of the less saturated color, one can achieve the more saturated or deeper color (as observed). This application in combination with light calibration (also known as clipping, which means that an artificial boundary is imposed for adding red or green to blue for further calibration of the brightness) results in a display that is calibrated for correctly observed colors of the human eye. However, an important consequence is that, since the brightness is changed, this means that for that specific color, when mixed with other saturated colors, the desired perceived color is no longer achieved. So, when using that calibrated color with less light output, the mixed color points are wrong. This can be easily solved by choosing the original (computationally correct) values.

In accordance with an aspect of the invention, the calibration data is calculated real-time (and therefore not stored) according to the current video content per individual pixel. Therefore, saturated colors are adjusted independently of mixed white, so that the adjusted white point does not change with changing saturated colors. The main advantage is hereby visual

BE2019 / 5196 overcome observation problems that have not yet been documented by the CIE color standards, without assuming brightness variations. Especially for narrow-band emitters (for example LEDs), mixed colors can give a visual perception that is completely different from what is being measured. In one aspect of the present invention, the colors of the light-emitting elements can be dynamically adjusted depending on the content of the video or images, by a color calibration technique, thereby creating the impression that much deeper saturated colors can be seen. This color calibration technique overcomes the disadvantages described above (for example visual perception problems) and gives us a means for adjustment and correction. Initial design should use this technique, especially for the blue channel (but can be used for all different channels if necessary).

Human eye factors can be distinguished in terms of resolution perception on the one hand and in terms of color perception on the other. With regard to resolution perception, it should be noted that this is most sensitive in the red component, and much less sensitive in the blue component (for example, try to read blue text on a black background). In the case of color perception, given the situation of the same brightness, the most sensitive is observed in x-direction and less sensitive in y-direction. Given the color perception with luminance variation, an extra dimension must be added, while less luminance is perceived as deeper or more saturated color.

The above is further taken into account in terms of color calibration calculations. According to an aspect of the invention, two calibration matrices are proposed instead of one for defining the final calibration, and thus a solution to the visual perception problems as described above is provided. One calibration matrix, also called MixMatrix, is defined as the matrix to be used when multiple colors are displayed simultaneously. The other matrix, hereinafter referred to as BlueMatrix, is defined as the matrix to be used when the saturated target color (in this example, blue) is to be displayed. This is usually the matrix where the brightness of the blue color is reduced, resulting in a deeper color perception. To obtain correct mixed colors and maintain the correct white point, a formula must be applied in which the final calibration matrix, hereinafter referred to as FinalMatrix, is a function of the input color values and can therefore be defined as a

BE2019 / 5196 function of the MixMatrix and the BlueMatrix, both related to a certain type of content respectively. The color calibration technique according to the invention is therefore also referred to as content-dependent calibration, while a weight factor depending on the content is used to calculate the final calibration matrix.

FinalMatrix = Factor. MixMatrix + (1 - Factor). BlueMatrix

The Factor in the above formula is 1 when only the blue saturated target color is to be displayed, i.e. no red and green colors are to be displayed. The Factor is equal to 0 when all (or more than one) color is available. All kinds of variations for the Factor can be derived. By way of example, the Factor can be:

Factor = 2 (Rin + Gin) / (Rin + Gin + Bin) where 0 <Factor <1

With the above definition of the Factor, the Factor is indeed 0 if there is no red or green in the signal. Then FinalMatrix = BlueMatrix. If there is a total signal R = 1, B = lenG = 0 then Factor becomes 1. In other words, if there is a total mix with a different color, the Factor becomes 1.

MixMatrix or Matrix1 and BlueMatrix or Matrix2 can be saved for each individual pixel of the display. The Factor is calculated using RGB input values (content) for that specific pixel. According to the formula, FinalMatrix can be calculated and then the traditional pipeline or calculation as described for the traditional calibration principle can be used. According to one embodiment, while Matrix1 and Matrix2 are stored, FinalMatrix is calculated in real-time. The principle can be used and / or expanded for all three or more primary colors in a display. In the case of a real-time malleable and transparent pixel-addressed device, such as a display, in accordance with the invention, one can use the same pipeline on top to compensate for viewing angle differences.

Figure 7 refers to the viewing angle graph of an example of an LED. It is striking that the brightness of the individual colors is different at an angle. However, this fact becomes very important in the case of a continuously moving position of the display or screen. By moving the position, an observer looking at the screen will also perceive different brightness of the individual pixels. If multiple primary colors are displayed, this means that the color dots are no longer correct. The above color calibration technique according to the invention can be applied with two or more matrices, e.g. Matrix1 is the matrix at a viewing angle of 0 °, Matrix2 is the matrix at a viewing angle of 45 ° horizontally and a third matrix

BE2019 / 5196

For example, MatrixS is vertical for the viewing angle of the LED at an angle of 45 °. For the final calculation of the calibration matrix, FinalMatrix can be defined as:

FinalMatrix = A. Matrixl + B. Matrix2 + C. MatrixS where A + B + C = 1

FinalMatrix will adjust depending on the angle used. That is why you can compensate real-time for color and brightness differences on the display.

For example, to detect angle variations on the display, one can e.g. add local gyros or local infrared markers. Such infrared markers can be interpreted by a processing system where feedback is given on the matrix processing side to determine R, G and B.

As previously stated, the invention provides a real-time malleable and transparent pixel-addressed device, such as a display (or display). The deformable character means that the calibration must also take place at an angle. In accordance with the invention, Figure 5 illustrates an embodiment of different types of display images 501, 503, 505, more specifically, in Figure 5 (a) becomes a fixed image 501, in Figure 5 (b) a deformable image, and in Figure 5 (c) a real-time malleable image, respectively, for which calibration can be applied. The fixed character of the fixed image 501 is indicated by straight lines 502, while the deformable character of the deformable image 503, 505 is indicated by curved lines 504, 506. In addition, the real-time deformability is further indicated in Figure 5 (c) with the arrow t where t stands for time.

The mechanical aspects of a real-time malleable and transparent pixel-addressed device, such as a display, in accordance with the invention, are now discussed. In general, these mechanical aspects refer to, for example, the interconnection between different parts of a display in accordance with the invention, as well as the encapsulation of such a display, e.g. by means of silicone, stretched in a frame, whether or not combined with nylon. To improve the robustness while maintaining transparency, the real-time deformable and transparent display in accordance with an embodiment of the invention can be embedded in a transparent thermoplastic material. Moreover, the transparent thermoplastic material applied over the LED can lead to a lens function (including for example a Fresnel lens), diffusion or another possible optical effect (for example stereoscopic, 3D or holographic). Polarizers could be provided with or in the transparent material so that a 3D

BE2019 / 5196 display could be generated. Moreover, due to the very high transparency of the display according to the invention, the display could also be used in typical Pepper's Ghost setup, and thereby also generate a kind of 3D display. According to another embodiment, not only is a transparent thermoplastic material provided, but the display also continues to have a degree of perforation, as is particularly desirable for outdoor applications. The perforation can be arbitrary or can correspond to the original display structure, in any case resulting in a lighter display in weight and less vulnerable to wind load. The transparent thermoplastic material, or possibly another - transparent or non-transparent - material in which the screen is embedded, can moreover be provided with further functionality such as, for example, local hardening, mechanical reinforcements, hooks, rings, knobs or interruptions for mechanical rigidity, or a connector for attaching a mechanical design according to the application, eg honeycomb floor mats or curtains. The local pavements can be used, for example, for all kinds of mechanical appendices or provisions, such as holes for screws, cords, buttons or buttons. The rack functionality or the deformable nature of the display according to the invention can be frozen locally by means of local hardening of certain parts of the display, instead of, for example, the entire display. According to an embodiment, the thermoplastic material is not only transparent, but also acoustically permeable, such that a display can be mounted in front of a loudspeaker, and therefore the display does not interfere in terms of audio signal reduction. According to a specific embodiment, a real-time deformable and transparent display with acoustic permeability is provided on a tensioned transparent MYLAR film, and then this MYLAR film is controlled by the electrostatic loudspeaker principle as known in the art. That is why a system is provided that jointly delivers sound and image. Of course, such MYLAR film requires stretchability and continuous formability, as well as the display that is applied to it. In contrast to acoustic permeability, according to an embodiment, the display according to the invention could also be provided with sound-absorbing material. Further referring to joining or attaching other parts to a display in accordance with the invention, it is noted that a display generally represented by a mesh or grid structure can be interpreted as traditional textiles in terms of

BE2019 / 5196 connectability through all possible connecting textile principles, including for example knitting, sewing, crocheting, sewing, pasting or pasting. Attachment of display parts or material to textiles, as well as connecting display parts to each other are interpreted here. By way of example, display parts could also be connected to each other by means of a zipper. In addition to those connecting textile mechanisms, embodiments also include attaching display parts (e.g., to each other or on a certain surface) by means of a permanent (e.g., glue, epoxy) or semi-permanent (e.g., post-it) adhesive.

According to a special embodiment, the deformable display according to the invention is combined with 3D printing applications. For example, 3D-printed material can be combined with a certain shaped deformable display.

In particular, it is mentioned that a deformable, i.e., stretchable and flexible display in accordance with the invention, can be rolled up because of its flexibility (and stretchability), and therefore transport of such a display can be facilitated in terms of space and manageability.

Particularly for outdoor display applications, LEDs are more favorable while being more robust than LCD, OLED or plasma and therefore resistant to harsh environmental conditions in terms of e.g. temperature or other weather conditions. For example, transparent OLED screens can be used in automotive applications, e.g. mounted on the rear window of a car can be used, although they quickly become exhausted or worn out due to degradation of the organic material due to high temperatures of direct impact from the sun. According to an embodiment of the invention, such a rapid deterioration (or deterioration) will not occur with a transparent LED display.

Given the above design choice of a real-time deformable and transparent display, the invention further addresses that the display and the support, ie the PCB, are one resulting in a much lighter display system than other standard comparable displays, requiring an additional frame. is on which further components are mounted. It is worth emphasizing that when using a flexible PCB as previously described, not only one side (front) but in fact both sides (front and back) of the flexible PCB can be used and therefore possible are covered with circuit components, LED nodes in particular, and stretchable electronics for example

BE2019 / 5196 meander electronic paths between the circuit components of an LED matrix display structure. In other words, the rear side next to the front side of the flexible PCB can be assembled and manufactured to display a display, and thus a double-sided deformable display is generated in accordance with the invention. The video or images or settings accordingly need not be similar or even identical on both sides and may therefore differ so that, for example, high quality video is applied on one side with high resolution, while the other side is used for example to display text only. such as can be thought of with an auto queue for broadcasting applications.

Referring now to Figure 6, an embodiment is provided for a real-time malleable and transparent pixel-addressed device 601, such as a display, in accordance with the invention. Vertical 603 and horizontal 602 conductive paths are illustrated herein, as well as pixels or LEDs 604 at nodes where these vertical 603 and horizontal 602 paths intersect. At locations between the pixels or LEDs 604, further functionality can be added by means of the additional nodes 606, which e.g. can be photovoltaic PV cells or infrared markers or sensors. However, such further functionality can also replace a regular LED or pixel by mounting the additional node 606a, should it be desired or required by the design of the pixel-addressed device 601, which can be embedded in or covered with thermoplastic material 605.

Claims (15)

Conclusions A method of manufacturing a deformable display, the method comprising: - supplying a printed circuit board; - providing an arrangement of pixels on the printed circuit board, - providing connections on the printed circuit board; - removing a substantial part of the printed circuit board in the areas where none of the pixels or connections between them are present. The method for manufacturing a malleable display according to claim 1, further comprising - providing a driver module at each individual pixel for controlling the pixels at the individual pixel level. The method for manufacturing a malleable display according to claim 1 or 2, further comprising - providing an arrangement of functional nodes between the arrangement of pixels, wherein the functional nodes are connected to the pixels, wherein the pixels are, for example, light-emitting elements, such as light-emitting diodes (LEDs), and wherein the functional nodes are, for example, photovoltaic ( PV) cells may or may not be provided with storage capacity, accelerators, gyroscopes, sensors, microphones / speakers, piezo elements, ultrasonic components, light-emitting elements. The method for manufacturing a malleable display according to claims 1 to 3, further comprising - providing a thermoplastic material, wherein the pixels are embedded interconnected, the thermoplastic material being, for example, transparent. The method for manufacturing a malleable display according to claim 4, further comprising BE2019 / 5196 - providing the thermoplastic material with perforations and / or hardened parts, and / or connecting parts, and / or mechanical adjustments or fittings, applied globally for the entire device, or else locally applied. The method for manufacturing a malleable display according to claim 4 or 5, further comprising - providing the thermoplastic material with fire-retardant material and / or with acoustically permeable material and / or sound-absorbing material, and / or optical components such as, for example, lenses, diffusers or polarizers. 7. A malleable display system comprising: - a number of printed circuit boards; - an arrangement of pixels on the number of printed circuit boards, such that at least a part of the number of printed circuit boards have one or more of the pixels mounted thereon, and such that the pixels are connected to each other; wherein connections to provide power to the pixels and / or to connect two or more of the pixels to each other are provided between the pixels or on the printed circuit boards; wherein at least one data connection from one pixel to the other is preferably provided between two or more of the pixels; and wherein the arrangement of pixels on the plurality of printed circuit boards, including connections between them, acts as a mesh-net support that is deformable at any time in any direction. The deformable display system of claim 7, further comprising - a driver module for each individual pixel, provided on the at least one of the number of printed circuit boards, for controlling the individual pixel. The deformable display system according to claim 7 or 8, wherein the pixels are light-emitting elements, such as, for example, light-emitting diodes (LEDs), such that the deformable display system is a light-emitting display system, such as, for example, an LED display system. The deformable display system of claims 7 to 9, wherein at least a portion of the plurality of printed circuit boards are flexible printed circuit boards and / or the pixels are connected to each other by means of conductive paths, for example stretchable conductive paths, e.g. made from copper. BE2019 / 5196 A color calibration method performed by a display system processing system comprising a storage module, which method comprises - a first set of color points is defined, wherein at least one color is in the minority; - a second set of color points is defined, the at least one color being in the majority; - a matrix formula is defined in which colors to be added to the first or second set of color points are calculated to achieve target colors for the first or second set of color points; - a first calibration matrix is defined by the matrix formula for the first set of color points; - a second calibration matrix is defined by the matrix formula for the second set of color points; - a matrix factor, being selectively selected in relation to the at least one color that is in the minority or majority of the first or second set of color points, is defined as a real number between 0 and 1; - a final calibration matrix is defined by the first and second calibration matrix, both being weighted based on the matrix factor. A color calibration method performed by a display system processing system, comprising a storage module, which method comprises - a first set of color points is defined for a first viewing angle; - a second set of color points is defined for a second viewing angle; - a third set of color points is defined for a third viewing angle; - a matrix formula is defined in which colors to be added to the first, second or third set of color points are calculated to achieve target colors for the first, second or third set of color points; - a first calibration matrix is defined by the matrix formula for the first set of color points; - a second calibration matrix is defined by the matrix formula for the second set of color points; BE2019 / 5196 - a third calibration matrix is defined by the matrix formula for the third set of color points; - a matrix factor, being selectively chosen in relation to first, second and third viewing angle color points, is defined as a real number between 0 and 1; - a final calibration matrix is defined by the first, second and third calibration matrix, each of which is weighted based on the matrix factor. A color calibration method performed by a display system processing system, comprising a storage module, which method comprises - a first to nth set of color dots is defined for a first to nth display characteristic related to color respectively; - a matrix formula is defined in which colors to be added to the first to nth set of color points are calculated to achieve target colors for the first to nth set of color points; - a first to nth calibration matrix is defined by the matrix formula for the first to nth set of color points; - a matrix factor, being selectively selected in relation to the first to nth screen characteristic related to color, is defined as a real number between 0 and 1; - a final calibration matrix is defined by the first to nth calibration matrix, each of which is weighted based on the matrix factor. The color calibration method according to claims 11 to 13, which is applied to a malleable display system as described in claims 7 to 10. A run-time color calibration method performed by a display system processing system comprising a storage module, the method comprising: (i) loading operational conditions of the display system; (ii) calculating a final calibration matrix, based on operational conditions, by combining or weighing first to nth calibration matrix, related to the determination of target colors to be achieved and stored in the storage module; and (iii) applying the final calibration matrix as calculated in step (ii).