SI26213A - ACTIVE LIQUID CRYSTAL MODULE FOR ADJUSTABLE CAR HEADLIGHTS AND OTHER LIGHTS AND LIGHTS WITH THE MENTIONED MODULE - Google Patents

Abstract

The invention belongs to the field of optics, especially lighting. The subject of the invention is an active liquid crystal (LC) module, which can change its optical properties in real time and thus enables an arbitrarily adjustable shape and intensity of the light beam, whereby the module includes: A light source that emits light for illumination; A liquid crystal cell that at least partially covers the light source; An external field that is in, on or at least partially surrounds the liquid crystal cell, for adjusting the state of the liquid crystal cell or the refractive index in the liquid crystal cell; A control unit that enables control of the external field and is preferably connected to the light source and optional sensors that detect the surroundings of the active liquid crystal module, on the basis of which the control unit adjusts the state of the liquid crystal cell in accordance with the machine learning algorithms used to program the control unit. The module has an undefined number of states, between which the switch will occur in response to the detected state in the surroundings of the lamp with the mentioned module

Description

ACTIVE LIQUID CRYSTAL MODULE FOR ADJUSTABLE CAR HEADLIGHTS AND OTHER LIGHTS AND LIGHTS WITH THE MENTIONED MODULE

The field of technology

In the context of physics, the invention belongs to the field of optics, namely to lamps in which the light generated by the light source is redirected using a system of lenses and reflectors. In the context of one of the possible ways of use, the invention also belongs to the field of vehicles, or lighting and signaling equipment for vehicles, especially headlights and fog lights. The subject of the invention is an active liquid crystal (TL) module, which can change its optical properties in real time and thus enables an arbitrarily adjustable shape and intensity of the light beam, as well as a lamp with the aforementioned liquid crystal module.

Background of the Invention and Technical Problem

A motor vehicle light typically consists of a light source, at least one reflector that reflects light from the light source, and a lens system that appropriately shapes the beam. More advanced headlights use an adaptive beam (AFS - Adaptive Front-Lighting system) and adjust the intensity and shape of the beam to the driving regime: e.g. (i) at lower speeds, the beam is wider, so that pedestrians and other road users can be seen more easily, and (ii) at higher speeds, typically above 100 km/h, the beam is much longer and narrower, thus more adequately illuminating the road when driving on highways. AFS systems can use both classic, HID (eg xenon lamps), LED lamps or laser light sources. Typically, the adjustment is made through the displacement of the light source and the lens system with electric actuators, but recently more and more developments are taking place in the direction of selective switching on and off parts of the source, such as e.g. (i) by selectively switching off individual parts of the light source or (ii) by a device that acts as a projector and allows only a certain part of the beam to pass through with shutters.

Both modes upgrade the existing matrix LED technology, where the light beam is adjusted by turning individual LED segments on and off. The first method with selective switching off of parts of the source is the implementation of small "pixel" LED segments that can be switched on or off individually. The specialty of the technology is the size of the source, as there is an LED chip with, for example, 1000 or more points on only 4x4 mm ² , and each point can reach a brightness of up to 4.6 lumens. A big advantage over projector lights is precisely the lower energy consumption, since unused parts of the light source can be switched off. On the other hand, projector lights offer more flexibility and the ability to display complex patterns, such as navigation symbols, on the surface of the road. This can be achieved by local shading of the light using a liquid crystal aperture with several thousand points of resolution between the light source and the lens.

The invention is based on the problem of how to change the light beam in a lamp into any spatially and temporally modulated shape in order to achieve the desired optical characteristics, during operation and according to certain external conditions. For this purpose, mechanical components can be used, such as moving mechanical mirrors known from patent application WO2014121315A1 or mechanically adjustable lenses described in patent application DE102019103898A1. Such solutions have the well-known drawback of using many mechanical parts. Alternatively, liquid crystals can be used to direct the light.

A technical problem that has not yet been satisfactorily solved is the modulation of the light beam into an arbitrary shape with the help of a liquid crystal module, namely in such a way that the light is redirected and not overshadowed.

State of the art

Several methods of directing light based on liquid crystals are described in the literature. One of the methods of directing light with a liquid crystal module in car headlights is described in patent EP 2 013 536 B1, where a special unit for a headlight is described, which consists of several consecutive liquid crystal cells. Each cell has two states: the first, which affects the light beam as little as possible, and the second state, which refracts the light beams according to the signal from the AFS headlight control unit. It switches between the two states with the help of two electrodes. In this way, the radiated light beam is influenced by adjusting it according to the predetermined regimes. This achieves the inclination of the light up or down and the width of the radiated beam. Liquid crystal cells can have a surface relief, different electrode shapes, can be anisotropically scattering cells, where several cells can be connected in parallel in rows.

Similarly, patent application WO 2018152644 A1 describes a device for AFS headlights based on a liquid crystal cell. Depending on the angle of the steering wheel and the detection of oncoming vehicles, the device can influence the width of the beam of light emitted via the liquid crystal cell via an electric field, separately for the left and right headlights. Several consecutive cells can be combined for more precise light modulation in two planes. The main disadvantage of the solution described in this patent application is that the beam spreads symmetrically on both sides and does not change its intensity distribution, which is usually not desirable.

Patent application DE 102016120222 A1 discloses a lighting device for a car headlight consisting of a mechanical regulation and an additional light controller. The light controller can be a DMD (micromirrors), a liquid crystal display (LCD or LCoS type) or a laser scanner. By using a combination of mechanical regulation and a light controller, it is achieved that the light controller works in a smaller area and can be simpler and smaller and therefore cheaper, while the mechanical regulation is not used for more frequent, fast and dynamic movements during driving and therefore its service life is extended . The device here includes both basic mechanical regulation and additional fine regulation of light. In the case of a liquid crystal screen, this regulation works point-wise and only changes the proportion of transmitted light in an individual point.

In the patent application EP 3 501 896 A1, he discloses a device with a liquid crystal cell that transmits the light beam of the dipped beam without interruption and modulates only the light beam of the high beam, which is done by determining the transmissivity of parts of the liquid crystal cell with the help of an electric field. By shading individual points (pixels) of the cell, a significant amount of the luminous flux of the long beam is lost, while the short beam remains unchanged and fixed. In this way, a considerable amount of luminous flux is lost and the emitted beam of light is only roughly transformed.

All the solutions described above are limited to a few predefined states, where they cannot affect the entire beam of light at once, or to achieve this they need several consecutive cells, which further reduces the light intensity and increases the complexity of the device itself. The modulation of the luminance of the source also reduces the overall intensity of the light, which is not desirable.

Description of the solution to the technical problem

The task and goal of the invention is the construction of an active liquid crystal module, which allows arbitrary and precise guidance of the light beam, whereby the module will have an undefined number of states, between which the switch will occur in response to the detected state in the surroundings of the lamp with the mentioned module. Active liquid crystal module includes:

- A light source that emits light for illumination,

- at least one liquid crystal cell that at least partially covers the light source, whereby it can change the emitted light from the light source into any shape with any intensity profile,

- An external field that is in, on, around or at least partially surrounds the liquid crystal cell, for adjusting the state of the liquid crystal cell or the refractive index in the liquid crystal cell,

A control unit that enables control of the external field and is preferably connected to the light source and optional sensors that detect the surroundings of the active liquid crystal module, on the basis of which the control unit adjusts the state of the liquid crystal cell in accordance with the machine learning algorithms used to program the control unit.

The control unit consists of a computational processing unit, memory and input and output modules and is adapted to actively real-time (i) read and process the electrical signal from the sensors and lighting settings by the user, (ii) recalculate the settings of the external fields affecting the liquid crystal cells, and (iii) sends appropriate electrical signals to a system of electrodes and/or conductors and/or coils and/or external field irradiating lasers.

The light source can be any suitable, but preferably emits white, monochromatic or polychromatic light, which can be incoherent, partially coherent or coherent (laser). A liquid crystal cell at least partially covers the light source, but it can cover it completely. It is also possible to implement it in a movable form, so that it mechanically moves with respect to the light source in known ways. There is at least one source of light, but there may be several, in which case the sources may be the same or different.

A liquid crystal cell can be implemented in different ways depending on the most efficient use. The cell is preferably designed as a glass plano-parallel cell, but it can be flat, curved, of different thicknesses, layers, or from an emulsion of liquid crystals in the host medium. The cell can also be wedge-shaped, from several layers, it can have a profiled surface or surfaces, or a cell with several "glasses" (cells with wells). The surface of the cells can be arbitrary, smooth or with a pattern. The surfaces of cells and colloidal particles or dispersed components can impose an arbitrary surface orientational arrangement of liquid crystal molecules. The arrangement can be rectangular, planar, degenerate planar, inclined and degenerate inclined. This orientational arrangement coincides with the local optical axis of the liquid crystal and affects the [transition of] light[s]. The cell may contain various types of birefringent liquid crystals that enable controlled guidance, modulation and scattering of light, wherein the liquid crystal is selected from the group of nematic liquid crystals, cholesteric liquid crystals, smectic liquid crystals, chiral nematics, liquid crystal dispersions with polymers, or combinations thereof . Liquid crystals can also be in droplets or in an emulsion.

In addition, to improve the optical properties or response to the external field, the liquid crystal can be doped with particles or nanoparticles of different dimensions, shapes and optical material properties, such as dielectric, conductor, ferromagnet. Colloidal particles that can be used to dope liquid crystals can be of different sizes, for example from 1 nm to 10 um, m shapes, such as spherical, cylindrical, ellipsoidal, toroidal with or without slot, flat, conical and their derivatives.

In order to achieve various complex patterns in the liquid crystal that would affect the conduction of light, the cell can be equipped with a suitable pump that allows the creation of a liquid crystal current in the cell, which can alternatively be achieved with the help of an external field that causes the particles to move with with which the liquid crystal is doped.

The properties of the liquid crystal in the cell are changed via an external field, which is part of the module according to the invention. The external field affects the orientation of the liquid crystal in the cell and thus the direction of the light emitted by the source. The external field can be electric, magnetic or laser, which is a combination of an electric and magnetic external field, but a combination of the aforementioned can also be used. The external electric field is applied via randomly arranged electrodes outside, on the surface and/or inside the liquid crystal cell. The electrodes can be on one or more surfaces of the cell and can form different geometric patterns, such as lines, a grid, and the like. Possible electrode types include (i) light transparent or opaque electrodes, or (ii) an electrode system in which the electrodes can be individually controlled. The external magnetic field is applied via current conductors of various shapes, when, for example, straight conductors, wires, coils are outside, on the surface or inside the cell. Conductor types include (i) light transparent or opaque conductors, (ii) conductor systems in which the conductors can be individually controlled. A combined electric and magnetic field can be created, among other things, by irradiating the cell with laser light from an external laser. The external laser must shine into the liquid crystal cell so that the EM field can change the TK arrangement and thus the local refractive index. Laser light can be linearly, circularly, or otherwise polarized. The focus of the laser can be adjusted depending on the cell, as well as the optical aperture and intensity cross-section of the laser beam. The control unit is properly connected to the external field so that the external field can influence the liquid crystal cell according to the desired illumination, i.e. distribution of light, so that the intensity of light in one place is locally reduced by redirecting it to another place.

The control unit consists of a calculation processor unit, memory and input and output modules. This control unit actively in real time (i) reads and processes the electrical signal from at least one sensor, preferably several sensors and lighting settings by the user, (ii) then recalculates the settings of the external fields affecting the liquid crystal cells, and (iii) sends appropriate electrical signals to the system of electrodes and conductors and irradiating lasers. Thus, the control unit creates complex orientation patterns of the liquid crystal in the cell through external fields and affects the optical properties of the cell. The control unit can also modify the output intensity profile by changing the brightness of the source. In the case of an electric or magnetic field, e.g. connected to the electrodes via analog voltage or current outputs.

According to the invention, the module does not have preset states between which the external field would switch, but instead adjusts the luminance, the shape of the illumination and the intensity distribution according to the perceived exterior of the module, which is enabled by the control unit. For this purpose, the appropriate sensors are preferably used, which are connected or connected to the control unit, and are used to detect the surroundings, for example the shape and course of the road, other traffic participants and other peculiarities, such as traffic signs, damage to the road, animals and the like. Sensors may include, but are not limited to, photo detectors, radar sensors, TOF cameras, photo cameras, thermal imaging cameras, gyroscopes and accelerometers, speedometers, GPS sensors, internet connection sensors and the like or any combination thereof. The control unit can also read data from other sensors in the vehicle or external data obtained via the network and other vehicles. The lighting settings by the user determine the input signal for the control unit that corresponds to the required lighting intensity profiles, such as e.g. dipped beam, main beam or fog beam profile, or a combination of the two, or a combination of all three. Based on the electric signal from the sensors and predetermined parameters of the external fields, the control unit calculates the required external field on the fly to achieve standard intensity profiles and thereby creates the desired output intensity profile based on the surrounding conditions (e.g. the slope and course of the road, other road users).

The active liquid crystal module according to the invention preferably has a feedback loop established, namely it has a sensor for detecting the distribution of light, which is connected to a control unit that checks whether the illumination is adequate with respect to the desired illumination. If the control unit detects that the lighting is not adequate, the control unit calculates the necessary changes and rearranges the settings of the external field affecting the liquid crystal cell. The control unit additionally corrects and modifies the external fields in such a way that, through interaction with dopants and current, it can redirect the light from areas where the actual intensity is greater than desired to areas where the actual intensity is less than desired and thereby approximates the actual intensity distribution desired. Modifications are made by switching different electrodes, coils, conductors or other components of the external field on and off differently, thus affecting the local refractive index of the liquid crystal.

The process computing unit for determining the external fields uses machine learning and artificial intelligence algorithms, among other things, it can use neural network algorithms and their derivative and generalization, which perform computationally demanding operations of calculating the distribution of the external fields necessary to achieve the desired orientation profile of the liquid crystal in the cell . Machine learning and artificial intelligence methods use model synthetic and real data for learning. In the machine learning process, a set of fields with real models is generated, where the director field is calculated based on the electric field and the optical field is created. The electric field and the optical image are then input data for the neural network, whereby the processing computing unit then learns with the multitude of input data generated in this way how to adjust the external field in order to achieve the desired form of illumination. When the lighting is adapted to the situation, it can be further optimized via a feedback loop. Algorithms in the control unit can be upgraded if necessary during the period of use.

The control unit recognizes the situation via the above-mentioned sensors, which it connects to the learned patterns with the help of machine learning algorithms, so that it can detect and recognize the surroundings and redirect the light accordingly. adjusts the distribution of light intensity by illuminating or shading certain areas, e.g. oncoming vehicles, pedestrians and traffic signs. It adjusts the lighting by adjusting the external field accordingly, which is calculated based on learned situations. The control unit can additionally communicate with the driver and other stakeholders in the traffic by redirecting part of the light with greater or lesser intensity or a different color or by projecting any light pattern onto the surface in front of the vehicle. The redirected part of the light can also indicate the movement of traffic participants predicted by the control unit.

The control unit can also be connected to and communicate with other networks, such as networks for determining the position of the vehicle, and in the same way projects e.g. directions for travel. In addition, the control unit can use the connection to the networks for determining the vehicle's position to predict the vehicle's path (eg the road turns into a curve). Such adaptation is also machine-learned, as described above.

Optionally, the module also has additional optical elements that additionally passively influence the distribution of light without active adjustment via the control unit. Additional optical elements include lenses, mirrors, semitransparent mirrors and lenses, polarizers, phase plates, optical fibers and waveguides.

The module, as described above, can be installed in new luminaires or in existing ones, so that it is only added to an already existing luminaire or used as a replacement for parts of the luminaire (e.g. lens). Additional optical elements can be part of an already existing headlight, into which the module according to the invention is installed.

The active liquid crystal module according to the invention and the lamp with it enables the creation of an arbitrary beam shape without predetermined discrete states, continuous switching between states and real-time changing of the beam according to detected external conditions and user settings. This is particularly suitable for lighting various driving scenarios, e.g. of other vehicles and road users with the aim of either reducing the blinding of others or attracting the driver's attention, and also displaying complex patterns on the road surface, such as navigation symbols.

The active liquid crystal module for adaptive car headlights and other lamps and lamps with the mentioned module will be described below with the help of an implementation example and pictures that show:

Figure 1 Active liquid crystal module according to a possible implementation example

Figure 2 Illustration of three examples of lighting with an active liquid crystal module, namely in the case of a) a combination of high beams and shaded lights, b) a combination of high beams and an additionally shortened beam in the opposite lane where another vehicle is approaching, and c) display of warning signs at a detected traffic sign and a pedestrian walking along the road.

According to the embodiment shown in Figure 1, the active liquid crystal module includes: - A light source 4 that emits light for illumination, an active liquid crystal element 1, which consists of a liquid crystal cell that covers the light source 4, whereby the emitted light from the light source 4 can change into an arbitrary shape with an arbitrary intensity profile, and the external field, which at least partially surrounds the liquid crystal cell, to adjust the state of the liquid crystal cell or the refractive index in the liquid crystal cell,

- Control unit 2, which enables control of the external field and is connected to light source 4, active liquid crystal element 1 or its external field and optional sensors 6 that detect the surroundings of the active liquid crystal module, based on which the control unit 2 adjusts the state of the liquid crystal cell in accordance with the machine learning algorithms 5 that are used to program the control unit 2. The machine learning algorithms include input data for the design beam, for example daytime running lights, fog lights, high beams, etc.

The external field is preferably an electric field defined by electrodes disposed in, on, or around the liquid crystal cell. The electrodes can be on one or more surfaces of the cell and can form different geometric patterns, such as lines, a grid, and the like.

The active liquid crystal element 1 arbitrarily directs the light from the source 4. The basic state of the liquid crystal cell can be such that, when the external field is switched off, it forms the light beam in the shape of the shaded lights. Thus, in the event of a system failure, such a headlight can still be used safely even in road traffic, and in the case of using only shaded lights, no energy is consumed.

With a suitable exterior modification, the module takes care of both low beam, high beam and possibly fog lights in just one device, creating patterns that are the same as high beam on one side and low beam on the other, so that the lane is illuminated for much longer than the opposite lane through which another vehicle can drive (fig

2a). Since the liquid crystal module can adjust the way of lighting, a lamp with such a module does not need a separate assembly for long, shaded lights or fog lights, which helps to implement simpler lighting elements on the vehicle.

In addition, the module allows the redirection of light from certain areas, e.g. in the case of oncoming vehicles (Figure 2b) or redirection to certain areas, e.g. pedestrians or traffic signs and the projection of arbitrary symbols (2c), which also helps to increase the passive safety of road users. When the sensors detect an approaching vehicle in the opposite lane, the control unit calculates the necessary changes to the external field based on patterns learned during machine learning, so that the beam of light in the lane is further shortened, thereby not blinding the driver of the oncoming vehicle, as shown in Figure 2b.

The control unit can also create such an external field that it can display different symbols in front of the vehicle, namely, for example, a triangle symbol for a detected traffic sign and/or a pedestrian symbol next to a detected pedestrian walking on the road, as shown in Figure 2c. If a pedestrian is detected on the road, the light is partially redirected to him, so that the driver of the vehicle can see him clearly. It is illuminated with shaded lights so that pedestrians are not blinded. The detected traffic sign on the other side of the road is additionally illuminated, so that the driver can more easily understand what the sign is showing and adjust the vehicle's driving accordingly. Such states are not programmed in advance, but are adjusted on the fly with the control unit or external fields. When the pedestrian and/or the sign is out of the detection field, the light beam changes again so that the lighting is as optimal as possible according to the driving situation.

Claims (15)

Patent claims 1. An active liquid crystal (TL) module for adaptive automotive headlights and other lights, characterized in that it includes: - A light source that emits light for illumination, - at least one liquid crystal cell that at least partially covers the light source, whereby it can change the emitted light from the light source into any shape with any intensity profile, - An external field that is in, on or at least partially surrounds the liquid crystal cell, for adjusting the state of the liquid crystal cell or the refractive index in the liquid crystal cell, - A control unit that enables control of the external field and is preferably connected to the light source and optional sensors that detect the surroundings of the active liquid crystal module, on the basis of which the control unit adjusts the state of the liquid crystal cell in accordance with the machine learning algorithms used to program the control unit , where the module has an undefined number of states, between which the switch will occur in response to the detected state in the surroundings of the lamp with the mentioned module. 2. Active TK module according to claim 1, characterized in that the control unit consists of a calculation processor unit, memory and input and output modules and is adapted to actively real-time: (i) reads and processes the electrical signal from the sensors and lighting settings by the user, (ii) calculates the settings of the external fields affecting the liquid crystal cells, and (iii) sends the appropriate electrical signals to the system of electrodes and/or conductors and/or coils and/or external field irradiation lasers. 3. Active TK module according to claim 1 or 2, characterized by the fact that the external field can be an electric, magnetic and/or laser field or a combination thereof, which continuously changes the TK arrangement and does not shade the light, but redirects it locally. 4. Active TK module according to claim 3, characterized in that the external field is formed by electrodes, conductors, laser sources, coils, which can be placed in the TK cell, on the surface of the TK cell or near the TK cell. 5. Active TK module according to claim 4, characterized in that the used electrodes and electrical conductors for the generation of external fields can be of any shape and are optically transparent or opaque and group or individually controlled. 6. An active TK module according to any one of the preceding claims, characterized in that it has an integrated feedback loop that includes sensors for detecting the distribution of the intensity of light emitted by the TK cell, the sensors being connected to the control unit so that the feedback loop operates so that after light is emitted through the TK cell, the distribution of light intensity is detected by sensors, which then transmit the information to the control unit, which is adapted so that it can adjust the external field, if necessary, so that the TK cell changes the distribution of the intensity of the emitted light. 7. An active TK module according to any of the previous claims, which is characterized by the fact that the sensors detect the shape and course of the road, other traffic participants and other special features, such as traffic signs, damage to the road, animals and the like, and the sensor can be a photo detector , radar sensor, TOF camera, photo camera, thermal imaging camera, gyroscope and accelerometer, speedometer, GPS sensor, internet connection sensor, or any combination of these. 8. Active TK module according to any of the preceding claims, characterized in that the liquid crystal is selected from the group consisting of nematic, chiral nematic, smectic, mixture, and polymer-liquid crystal dispersion. 9. Active TK module according to the previous claim, characterized in that the liquid crystal is doped, for example with nanoparticles. 10. An active TK module according to any of the previous claims, characterized in that it has several different light sources with different wavelengths and any light pattern is projected onto the surface in front of the vehicle with greater intensity or a different color. 11. Active TK module according to any of the preceding claims, characterized in that it additionally includes a module for wireless connection to the Internet. 12. A lamp including an active TK module according to any of the preceding claims. 13. A lamp according to the previous claim, which is a car headlight or projector. 14. Lamp according to the preceding claim, where the lamp is a car headlight upgraded with an active TK module according to any one of claims 1 to 10 as an additional optical element for redirecting light. 15. Lamp according to claim 12 or 13, where the basic state of the TK module is such that the emitted light intensity is the same as a normal shaded headlight.