Optical device with liquid crystal element

Abstract

The present invention relates to the field of optical devices for motor vehicles, more particularly to such optical devices comprising a liquid crystal element. The present invention relates to an optical device (4, 4') for a motor vehicle (1, 1'), the optical device comprising at least one light source and one liquid crystal element (12, 12'), the light source being configured to emit light rays towards the liquid crystal element (12, 12').

Description

[0001] This invention relates to the field of optical devices for motor vehicles, and more particularly to optical devices including liquid crystal elements.

[0002] Vehicles, especially motor vehicles, are typically equipped with lights that enable various luminous functions, specifically illuminating the road or signaling the presence of a vehicle to other users. For example, this illumination corresponds to low beam or low beam functionality, while this signaling corresponds to DRL (daytime running light) functionality or other functions, such as position lights or indicator lights that allow for changes in direction.

[0003] Motor vehicle lights are becoming increasingly compact, with a single light-emitting module capable of producing multiple lighting functions, particularly both illumination and signaling. To perform lighting functions within a motor vehicle, the vehicle is equipped with a light-emitting module on at least one of its front or rear sides. This module is dedicated to at least one lighting function, such as signaling or illumination. When the lighting function is not in use, i.e., when the signaling or illumination function is deactivated, it may be desirable to modify the appearance of the vehicle surface to conceal the light-emitting module for aesthetic reasons.

[0004] In this context, the aim is to emit beams of light specific to each of the light-emitting functions produced by the module through the same illumination area. In other words, to improve the visual uniformity of vehicle lighting, it is desired that an observer outside the vehicle sees the same area illuminated, regardless of whether the light is performing a lighting or signaling function. Therefore, the illuminated area is the same during the day and at night.

[0005] In order to achieve the best perceived contrast suitable for the luminous function, the surfaces of vehicles involving both the signal beam and the illumination beam must have different visual appearances when they are not illuminated.

[0006] It is also desirable to hide the light-emitting modules in the front or rear when these light-emitting functions are not in use, especially for aesthetic reasons. In addition to these aesthetic considerations, the surface of a motor vehicle can then be used to display pictograms, which are visible to people near the vehicle, provided that the contrast on that surface of the vehicle is sufficient.

[0007] As can be deduced from the above, the goal is to obtain an optical device that can perform at least one light-emitting function, the appearance of which is modified when the light-emitting function is not used; or to perform multiple light-emitting functions, which have common visual characteristics both day and night when these light-emitting functions are enabled, and when these light-emitting functions are not enabled, the light-emitting module presents a visual appearance that is consistent with the visual appearance of the vehicle surface.

[0008] A known approach in the prior art is to use screens equipped with PLDC (Polymer Dispersed Liquid Crystal) films to achieve the same characteristics during the day and night. These PLDC screens are interposed between the light source and the output surface of the light-emitting module, enabling two different light-emitting functions: a signal transmission function corresponding to the PLDC film's off mode and an illumination function corresponding to the PLDC film's on mode. Therefore, when using the signal transmission function, the screen is in a diffuse state, while when using the illumination function, the screen is in a transparent state. However, screens equipped with PLDC films do not achieve high contrast because they appear white and diffuse in a relaxed state, and it is also difficult to achieve a satisfactory off state for PLDC screens.

[0009] A known prior art approach is to use a semi-transparent screen or a screen that transmits light in a limited manner to shield the light-emitting module. However, such a low-transmittance screen must be placed in front of the light-emitting module to hide it, and then its low transmittance hinders the implementation of the light-emitting function. Furthermore, US 2023 / 0273492 A1 discloses an optical device comprising a substrate, a light-emitting device facing a reflective layer, a resin layer, and a light transmission control layer comprising a liquid crystal layer containing cholesteric liquid crystal. Moreover, prior art devices do not describe a light-emitting device facing a liquid crystal layer that can only be passed through after light reflection. However, the device described in this US patent application does not provide two different light-emitting functions in the same compartment of a vehicle, nor does it provide at least one light-emitting function by modifying the appearance of the optical device when the light-emitting function is not in use.

[0010] - First optical device with liquid crystal element The present invention aims to overcome the shortcomings of the prior art by proposing an optical device capable of performing at least two different light-emitting functions in the same section of a motor vehicle, which in turn has a high contrast particularly suitable for pictographic display.

[0011] Therefore, the present invention relates to an optical device for a motor vehicle, the optical device comprising at least one light source and a liquid crystal element, the light source being configured to emit light in the direction of the liquid crystal element, the optical device including a power supply device, the liquid crystal element being capable of presenting: a first decorative configuration in which the liquid crystal element blocks the passage of light; a second luminescent configuration in which light emitted by the light source passes through the liquid crystal element; and a third luminescent configuration different from the second luminescent configuration in which light emitted by the light source passes through the liquid crystal element, the liquid crystal element changing from one configuration to another according to an instruction from the power supply device to generate or not generate voltage.

[0012] In the first decorative configuration, the liquid crystal element blocks the passage of light, for example, emitted by a light source and / or light from outside the vehicle.

[0013] The optical device according to the invention is intended to be fitted in a motor vehicle to perform light-emitting functions, particularly a first light-emitting function corresponding to a signaling function at the front and / or rear of the vehicle and a second light-emitting function corresponding to an illumination function at the front of the vehicle. The signaling function is, for example, a turn signal light, a daytime running light function called a DRL, a position light function, or a reversing light function, while the illumination function corresponds to the activation of low beam or high beam headlights. Preferably, the optical device further includes an optical surface, wherein a liquid crystal element is interposed between the light source and the optical surface of the optical device, the optical surface forming the illuminated surface of the optical device. The optical device is configured such that the optical surface through which light emitted from the vehicle passes is identical for both light-emitting functions. Thus, the optical surface is located between the liquid crystal element and another element on or in contact with the exterior of the motor vehicle, and the optical surface is preferably a layer that allows light emitted by the light source to pass through for the second and third light-emitting configurations and allows light emitted from the exterior to pass through for the first decorative configuration.

[0014] Therefore, in the second and third light-emitting configurations, light emitted by the light source passes through the liquid crystal element and the optical surface; and in the first decorative configuration, light emitted from outside the vehicle is reflected on the liquid crystal element.

[0015] Preferably, the optical surface is a layer with a thickness ranging from 1 mm to 6 mm, more preferably from 2 mm to 5.5 mm, more preferably from 3 mm to 5 mm, and even more preferably from 3.5 mm to 4.5 mm.

[0016] Preferably, the optical surface comprises one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyimide (PI), and polyethylene naphthalate (PEN). More preferably, the optical surface comprises one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA). More preferably, the optical surface comprises polymethyl methacrylate (PMMA).

[0017] Preferably, 80% to 100%, more preferably 85% to 100%, more preferably 90% to 100%, and even more preferably 95% to 100% by weight of the optical surface is one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA), more preferably polymethyl methacrylate. In other words, the optical surface is substantially composed of one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA), more preferably polymethyl methacrylate, and even more preferably polymethyl methacrylate (PMMA).

[0018] Preferably, the optical device further includes a protective layer located between the optical surface and the exterior of the vehicle.

[0019] Preferably, the liquid crystal element is a liquid crystal layer with a thickness ranging from 10 micrometers to 40 micrometers, more preferably from 15 micrometers to 30 micrometers.

[0020] Preferably, the optical device of the present invention comprises a single liquid crystal element, i.e., a single liquid crystal layer.

[0021] The liquid crystal element preferably comprises a liquid crystal solution contained between two substrates, particularly transparent electrode films. The substrates are located on either side of the liquid crystal element, such as... Figure 2 As shown. Therefore, the liquid crystal is contained between the first electrode and the second electrode, both of which are arranged in the path of the light emitted by the light source and between the light source and the optical surface.

[0022] Preferably, the optical device includes a single liquid crystal element located between two substrates, more preferably between two transparent electrode films.

[0023] The optical device includes a power supply that allows the configuration of the liquid crystal element to be changed. Therefore, the liquid crystal element can alternate between three different configurations (including a first decorative configuration, a second luminescent configuration, and a third luminescent configuration) depending on the voltage generated by the power supply. The second luminescent configuration corresponds, for example, to the execution of a signal emission function, while the third luminescent configuration corresponds to the execution of an illumination function. In the context of this invention, the configuration exhibited by the liquid crystal element depends on the orientation of its liquid crystals, which varies according to the applied electric field. Therefore, the liquid crystal element can allow light emitted by a light source to pass through or block such light. The transition from one configuration to another is achieved by controlling the power supply.

[0024] The first configuration is a stable configuration obtained in the absence of an electric field, while the second and third configurations are achieved by supplying a predetermined power value, which is continuously applied during the desired light-emitting function. For example, the second configuration is obtained by applying a pulsed electrical value, while the third configuration is obtained by applying a continuous electrical value with alternating polarity. In other words, each configuration is a persistent configuration lasting at least several seconds, rather than a temporary intermediate state for transitioning from one configuration to another; the configuration is maintained as long as the power supply current to the liquid crystal element remains at the predetermined value. A given configuration is not intended to be maintained indefinitely; therefore, the liquid crystal may change state after a period of use with optical devices. Thus, a stable or persistent configuration is not necessarily indefinite.

[0025] Preferably, the first decorative configuration is a reflective configuration, wherein the liquid crystal element not only blocks light from passing through but also reflects light emitted from outside the vehicle through the orientation of the liquid crystal in the element.

[0026] Preferably, the light emitted from outside the vehicle is unpolarized.

[0027] This reflective configuration gives the surface of the vehicle, which integrates optics, at least a partially mirror-like appearance. The reflective configuration is achieved through the orientation of liquid crystals, in which, in the first decorative configuration, the liquid crystals allow light from outside the vehicle to be reflected.

[0028] Alternatively, the first decorative configuration is preferably a colored configuration in which the liquid crystal element is colored.

[0029] Coloring configurations enable, for example, the creation of black optical surfaces. This coloring configuration is specifically achieved by adding dyes of the desired color within the liquid crystal element.

[0030] Preferably, in the first decorative configuration, the liquid crystal of the liquid crystal element is in a planar state.

[0031] In this planar state, the liquid crystal extends at least partially parallel to the electrode extension of the film of the liquid crystal element.

[0032] Preferably, the planar state of the liquid crystal is obtained without the presence of a voltage generated by the power supply device.

[0033] In other words, the planar state of the liquid crystal does not require an electric field, therefore the first decorative configuration corresponds to the off state of the optics. Thus, this planar state corresponds to the default state of the liquid crystal; more specifically, the first decorative configuration is the default configuration of the liquid crystal element. This allows for limiting the consumption of optics.

[0034] In the second light-emitting configuration, preferably, the light emitted by the light source passes through the liquid crystal element, or the optical device includes a second light source, and the light emitted by the second light source is reflected and / or transmitted by the liquid crystal element.

[0035] Preferably, the optical device further includes a second light source configured to emit light, wherein the second light source is laterally positioned relative to the optical surface. Preferably, the second light source is used in a second configuration.

[0036] Preferably, the second luminescent configuration corresponds to the diffuse configuration.

[0037] This diffuse configuration is particularly suitable for implementing signal emission functions. The diffuse configuration allows, for example, 50% to 70% light transmission, preferably about 60%.

[0038] For example, the liquid crystal element is configured to present a second light-emitting configuration corresponding to a diffuse configuration, wherein a second light source is activated to emit light into an optical surface that serves as a light guide and is in contact with the liquid crystal element, and the light flowing through the optical surface is reflected on the liquid crystal element and passes through the optical surface to the outside, thereby performing a low-intensity light-emitting function.

[0039] Preferably, in the second light-emitting configuration, the liquid crystal of the liquid crystal element is at least partially in a focal conical state. In other words, the liquid crystal of the liquid crystal element has a focal conical shape.

[0040] In their focal conical state, the liquid crystals are grouped into multiple groups, each group extending in the elongation direction, and each group contains a number of liquid crystals. Within each group, the liquid crystals are arranged relative to each other such that they form a spiral along the elongation direction. The elongation directions of these groups are randomly oriented.

[0041] Optionally, in addition to a light source configured to emit light in the direction of the liquid crystal element, the optical device also includes one or more additional light sources positioned on at least one side of the optical surface, optionally on both sides of the optical surface. The light source and the one or more additional light sources operate independently of each other. Thus, if one is on, the other can be off. The light sources can also be on simultaneously. In this diffuse configuration, light is emitted by one or more additional light sources, and this light flows through the optical surface acting as a light guide and is reflected on the liquid crystal element, performing a low-intensity signaling function (e.g., a position lamp). Therefore, a second light-emitting configuration as a diffuse configuration can also be used in the optical device according to the invention, wherein the additional light source is arranged laterally relative to the liquid crystal element. This additional light source is added to the light source illuminating the facing liquid crystal element. The light sources operate independently of each other, and the light sources can be lit individually or simultaneously. In the case of such an optical device with side illumination, the second light-emitting configuration can allow the light emitted by the additional light source to be reflected. In this configuration, the optical surface is preferably a layer with a thickness ranging from 1 mm to 6 mm, more preferably from 2 mm to 5.5 mm, more preferably from 3 mm to 5 mm, and even more preferably from 3.5 mm to 4.5 mm.

[0042] Alternatively, the diffuse configuration is implemented by a light source configured to emit light in the direction of the liquid crystal element at a reduced intensity compared to the intensity used for the third luminescent configuration (i.e., the transparent configuration, where the liquid crystals of the element are vertically aligned, allowing for illumination). The light passing through the liquid crystal element (liquid crystal layer) performs a high-intensity signaling function (e.g., for daytime running lights and turn signals).

[0043] Preferably, the focal conic state of the liquid crystal is obtained by applying a pulse voltage (regardless of whether the polarity is changed). This state can also be obtained by gradually eliminating the electric field.

[0044] The application of this voltage corresponds, for example, to control via pulse width modulation (also known as PWM). In this example, the voltage signal changes very rapidly between zero and non-zero values ​​(also known as peak values) at a frequency exceeding the saturation threshold observed by the human eye. With this control, a voltage average that remains substantially the same over time can be obtained; it should be remembered that the average value depends on the peak voltage and the applied duty cycle. The electrical signal advantageously exhibits polarity reversal, specifically from positive to neutral and then to negative, and conversely from negative to neutral and then to positive.

[0045] Preferably, the third luminescent configuration corresponds to the transparent configuration.

[0046] This transparent configuration is particularly suitable for implementing lighting functions. The liquid crystal element allows the light required for this lighting function to pass through without blocking the light, thus obtaining a beam of light that meets regulatory requirements.

[0047] Preferably, in the third light-emitting configuration, the liquid crystals of the liquid crystal element are arranged vertically.

[0048] Preferably, the vertical alignment of the liquid crystals is obtained by applying a voltage with a change in polarity, the absolute value of which is constant.

[0049] The vertical alignment corresponds to the arrangement of liquid crystals relative to each other.

[0050] In the third light-emitting configuration, the liquid crystal of the liquid crystal element is preferably perpendicular to the electrode of the film of the liquid crystal element.

[0051] Preferably, the liquid crystal in the liquid crystal element is a nematic liquid crystal or a cholesteric liquid crystal, more preferably a cholesteric liquid crystal.

[0052] Preferably, the liquid crystal of the liquid crystal element comprises (more preferably) 1'',7''-bis(4-cyanobiphenyl-4'-yl)heptane (CB7CB). .

[0053] Cholesteric liquid crystals have a helical structure suitable for optical devices.

[0054] Preferably, alternatively, the liquid crystal of the liquid crystal element comprises (more preferably) a mixture of the following: , , and Preferably, the mixture contains 51% by weight of 25% by weight 16% by weight and 8% by weight The percentage by weight is based on the weight of the mixture.

[0055] Optionally, the liquid crystal element comprises one or more chiral agents. Preferably, based on the weight of the liquid crystal element comprising one or more chiral agents, the chiral agent content is in the range of 1% to 6% by weight, preferably 2% to 5.5% by weight, and preferably 3% to 5% by weight.

[0056] Preferably, the liquid crystal of the element is a nematic liquid crystal to which one or more chiral agents can be added. This produces a cholesteric phase structure.

[0057] Preferably, the liquid crystal element comprises a dye. The use of a dye is advantageous according to the invention because it allows for broadening of the absorption spectrum and provides color freedom that cannot be obtained solely by adjusting the helical pitch of the cholesteric liquid crystal.

[0058] These dyes are preferably dichroic dyes. When the liquid crystal element is in its first decorative configuration, these dyes allow the optical surface to be endowed with the desired color. The dyes are oriented within the liquid crystal element in the same manner as the liquid crystal, positioning themselves within the space left by the liquid crystal. This results in the dye orientation being substantially the same as that of the liquid crystal, i.e., in the first decorative configuration, the orientation is substantially parallel to the electrodes of the liquid crystal element, and in the third luminescent configuration, the orientation is substantially perpendicular to the electrodes, with the movement of the liquid crystal under the influence of an electric field causing the movement of the dyes. It will be understood that, like the liquid crystal, the dyes do not interfere with the propagation of light in the third luminescent configuration.

[0059] According to the invention, there are no limitations on the dyes, as long as they are preferably soluble in liquid crystals, for example, at operating temperatures in the range of -40°C to 100°C. For example, the dye may be a mixture comprising one or more of the following: 4-dimethylamino-4'-nitroazobenzene (DNANAB). , , , , , , , , , , ,and Where X = -C2H5 or -OC5H 11 Or -N(CH3)2 or -C4H9.

[0060] Preferably, the dye allows for the production of black.

[0061] Preferably, based on the weight of the liquid crystal element containing the dye, the dye content in the liquid crystal element is not more than 10% by weight, more preferably not more than 9% by weight, more preferably within the range of 0.5% to 8% by weight, more preferably 1% to 6% by weight, more preferably 1.5% to 5% by weight, and more preferably 2% to 4% by weight.

[0062] In the context of this invention, and not to be bound by any theory, it should be noted that if the dye content is greater than 10% by weight based on the weight of the liquid crystal element containing these dyes, this may adversely affect the illumination in the third light-emitting configuration corresponding to the vertical alignment state of the liquid crystal of the liquid crystal element.

[0063] Preferably, in addition to liquid crystal, the liquid crystal element also comprises one or more polymers. Thus, the liquid crystal is stabilized in a network of one or more polymers. For example, one or more polymers are acrylate polymers. Under these conditions, the element can be referred to as a polymer network-stabilized liquid crystal. If present, the one or more polymers are included in the liquid crystal element in an amount preferably from 1% to 50% by weight, more preferably from 1% to 30% by weight, more preferably from 1% to 10% by weight, and even more preferably from 5% to 10% by weight, based on the weight of the liquid crystal element containing said one or more polymers.

[0064] Therefore, liquid crystal elements differ from PDLC (polymer dispersed liquid crystal) films, which have a higher polymer content.

[0065] Preferably, alternatively, the liquid crystal of the liquid crystal element is not dispersed or stabilized in the polymer network.

[0066] Preferably, the liquid crystal element includes multiple addressable portions, each of which is independently controllable.

[0067] Each addressable portion can be controlled to independently present one of a first, second, and third configuration. For example, each addressable portion of a liquid crystal element can correspond to a pixel on the optical surface of an optics device. The addressable portions can be controlled using passive matrix addressing techniques. By independently controlling the addressable portions of the liquid crystal element, a portion of the optical surface can be placed or held in a decorative configuration—in other words, in a configuration where light emitted by a light source does not exit—while the entire remaining portion of the optical surface is held or placed in a signaling or illumination configuration—in other words, in a configuration where light emitted by a light source exits from the optics device. Where appropriate, this control can allow the creation of pictograms or animations on the optical surface.

[0068] The present invention also relates to a motor vehicle including the optical device as described above, wherein the optical device is arranged at the front of the motor vehicle.

[0069] Alternatively or additionally, the present invention relates to a motor vehicle that includes the optical device described above, wherein the optical device is arranged at the rear of the motor vehicle.

[0070] - Second optical device with liquid crystal element The present invention aims to overcome at least one of the above-mentioned disadvantages by proposing an optical device that allows for the optimal execution of at least one light-emitting function, the appearance of which is modified when the light-emitting function is not implemented.

[0071] Therefore, the present invention relates to an optical device for a motor vehicle, the optical device comprising at least one light source and a liquid crystal element, the light source being configured to emit light in the direction of the liquid crystal element, the optical device comprising a power supply device capable of generating an electric field to change the state of the liquid crystal element to place the liquid crystal element in: a first decorative configuration in which the liquid crystal element blocks the passage of light; or a second luminescent configuration in which light emitted by the light source passes through the liquid crystal element, the liquid crystal being configured to be stable in both configurations in the absence of an electric field generated by the power supply device.

[0072] In the first decorative configuration, the liquid crystal element blocks the passage of light, for example, emitted by a light source and / or light from outside the vehicle.

[0073] The optical device according to the invention is intended to be fitted in a motor vehicle to perform a light-emitting function, particularly a signaling function or an illumination function. Preferably, the optical device further includes an optical surface, wherein a liquid crystal element is interposed between the light source and the optical surface, and the light-emitting function is visible on the optical surface.

[0074] Preferably, the optical surface is located between the liquid crystal element and the exterior of the vehicle (the exterior portion of the vehicle) or an element in contact with the exterior of the vehicle. The optical surface is preferably a layer that allows light emitted by a light source to pass through for a second light-emitting configuration and allows light emitted from the exterior to pass through for a first decorative configuration. The optical surface advantageously maintains optimal contact with the liquid crystal element, thereby allowing for good optical operation of the assembly.

[0075] Therefore, in the light-emitting configuration, light emitted by the light source passes through the liquid crystal element and the optical surface; and in the decorative configuration, light emitted from outside the vehicle is reflected on the liquid crystal element.

[0076] Preferably, the optical surface is a layer with a thickness ranging from 1 mm to 6 mm, more preferably from 2 mm to 5.5 mm, more preferably from 3 mm to 5 mm, and even more preferably from 3.5 mm to 4.5 mm.

[0077] Preferably, the optical surface comprises one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), polymethyl methacrylate (PMMA), polystyrene (PS), polyimide (PI), and polyethylene naphthalate (PEN). More preferably, the optical surface comprises one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA). More preferably, the optical surface comprises polymethyl methacrylate (PMMA).

[0078] Preferably, 80% to 100%, more preferably 85% to 100%, more preferably 90% to 100%, and even more preferably 95% to 100% by weight of the optical surface is one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA), more preferably polymethyl methacrylate (PMMA). In other words, the optical surface is substantially composed of one or more of the following: polyethylene terephthalate (PET), polycarbonate (PC), and polymethyl methacrylate (PMMA), more preferably polymethyl methacrylate.

[0079] Preferably, the optical device further includes a protective layer located between the optical surface and the exterior of the vehicle.

[0080] Preferably, the liquid crystal element is a liquid crystal layer with a thickness ranging from 10 micrometers to 40 micrometers, more preferably from 15 micrometers to 30 micrometers.

[0081] Preferably, the optical device of the present invention comprises a single liquid crystal element, i.e., a single liquid crystal layer.

[0082] A liquid crystal element is, for example, a film, in which liquid crystal is contained between a first electrode and a second electrode of the film, the first electrode and the second electrode forming a wall, both of which are arranged in the path of light emitted by a light source.

[0083] Preferably, the optical device includes a single liquid crystal element located between two substrates, more preferably between two transparent electrode films.

[0084] The optical device includes a power supply that allows the configuration of the liquid crystal element to be changed. Therefore, the liquid crystal element can alternate between two different configurations (i.e., a first decorative configuration and a second luminescent configuration) depending on the electric field generated by the power supply. In this case, the second luminescent configuration corresponds to the execution of a signal transmission function or an illumination function.

[0085] The configuration of a liquid crystal element depends on the orientation of its liquid crystals, which varies with an electric field. Therefore, a liquid crystal element can allow light emitted by a light source to pass through or block it. The transition from one configuration to another is achieved by controlling a power supply device.

[0086] Both configurations possess stable characteristics; in other words, they do not require a constant electric field generated by a power supply. Furthermore, maintaining either configuration does not require a permanent electric field. This allows for a reduction in the power consumption of motor vehicles equipped with the optical devices according to the present invention. Moreover, the stability of the liquid crystal in the liquid crystal element eliminates the need for thin-film transistors (TFTs), which are expensive components typically used in optical devices.

[0087] Stability is defined based on the duration for which the configuration is maintained at the same level. In some embodiments, this duration is approximately two to three seconds. In other embodiments, the duration is longer. The duration depends particularly on the properties of the liquid crystal in the liquid crystal element. Where appropriate, a refresh voltage can be applied to maintain a given configuration. A stable configuration is not intended to be maintained indefinitely; therefore, the liquid crystal may change state after a period of use with the optics. Thus, a stable configuration is not necessarily maintained indefinitely. Advantageously, it is maintained for the duration of the device's use, for example, until the optics are turned off.

[0088] The two stable configurations of the liquid crystal in a liquid crystal element arise from the competition between two factors: on the one hand, the arrangement of the liquid crystal with one of the electrodes of the liquid crystal element; on the other hand, the chiral effect caused by the presence of a chiral agent within the liquid crystal element. Optionally, the liquid crystal element contains one or more chiral agents. Preferably, the content of the chiral agent is in the range of 1% to 6% by weight, preferably 2% to 5.5% by weight, and preferably 3% to 5% by weight, based on the weight of the liquid crystal element containing the chiral agent. An example of a chiral agent, especially a chiral agent used for cholesteric liquid crystals, is a dopant, such as S5011, which is used at a concentration of 4.5% by weight based on the weight of the liquid crystal element containing the agent.

[0089] Preferably, the transition of the liquid crystal element from one configuration to another is achieved by occasionally applying a voltage corresponding to a set value through a power supply device.

[0090] The applied voltage allows an electric field to be generated. Therefore, a device can be switched from one configuration to another by applying a set value without maintaining the electric field. This transition from one configuration to another can be achieved by applying an occasional voltage, which can be sudden or gradual. For example, the device switches from a first decorative configuration to a second luminous configuration when a first voltage value is applied, and the second luminous configuration remains stably maintained for at least a few seconds during this power interruption. Then, the device switches from the second luminous configuration back to the first decorative configuration when a second voltage value different from the first voltage value is applied.

[0091] Preferably, the first decorative configuration is a reflective configuration, wherein the liquid crystal element not only blocks light from passing through but also reflects light emitted from outside the vehicle through the orientation of the liquid crystal in the element.

[0092] Preferably, the light emitted from outside the vehicle is unpolarized.

[0093] This reflective configuration gives the vehicle, which integrates optics, a mirror-like appearance. The reflective configuration is achieved through the orientation of liquid crystals, in which the liquid crystals allow light from outside the vehicle to be reflected.

[0094] Alternatively, the first decorative configuration is preferably a colored configuration.

[0095] Coloring configurations enable, for example, the creation of black optical surfaces. This coloring configuration is specifically achieved by adding dyes of the desired color within the liquid crystal element.

[0096] Preferably, in the first decorative configuration, the liquid crystal of the liquid crystal element is in a planar state.

[0097] In this planar state, the liquid crystal extends at least partially parallel to the electrode extension of the film of the liquid crystal element.

[0098] Preferably, the planar state of the liquid crystal is obtained without applying an electric field.

[0099] In other words, the planar state of a liquid crystal does not require an electric field. Therefore, the planar state corresponds to the default state of the liquid crystal; extendedly, the first decorative configuration is the default configuration of the liquid crystal element.

[0100] Preferably, the first decorative configuration corresponds to the standard configuration of the liquid crystal.

[0101] Therefore, when the vehicle, which includes optics, is not in use, the default configuration is the first decorative configuration.

[0102] Preferably, the second light-emitting configuration is selected from signal-emitting configurations and illumination-emitting configurations. In the context of this invention, the second light-emitting configuration may alternatively be a signal-emitting configuration or an illumination-emitting configuration.

[0103] Therefore, the second light-emitting configuration of the liquid crystal element corresponds to the signal-emitting function or the illumination function of a motor vehicle.

[0104] Signaling functions include turn signals or daytime running lights (DRLs), while lighting functions correspond to turning on the low beam or high beam headlights.

[0105] Preferably, the second luminescent configuration corresponds to the diffuse configuration.

[0106] Preferably, the signal emission configuration corresponds to the diffuse configuration.

[0107] In the second light-emitting configuration, preferably, the light emitted by the light source passes through the liquid crystal element, or the optical device includes a second light source, and the light emitted by the second light source is reflected and / or transmitted by the liquid crystal element.

[0108] A diffuse configuration allows, for example, 50% to 70% light transmission, preferably greater than 60%.

[0109] Preferably, in the signal emission configuration, the liquid crystal of the liquid crystal element is in a focal cone state.

[0110] In their focal conical state, the liquid crystals are grouped into multiple groups, each group extending in the elongation direction, and each group contains a number of liquid crystals. Within each group, the liquid crystals are arranged relative to each other such that they form a spiral along the elongation direction. The elongation directions of these groups are randomly oriented.

[0111] Preferably, the optical device further includes a second light source configured to emit light, wherein the second light source is laterally positioned relative to the optical surface. Preferably, the second light source is used in a signal emission configuration.

[0112] For example, the liquid crystal element is configured to present a second light-emitting configuration corresponding to a diffuse configuration, wherein a second light source is activated to emit light into an optical surface that serves as a light guide and is in contact with the liquid crystal element, and the light flowing through the optical surface is reflected on the liquid crystal element and passes through the optical surface to the outside, thereby performing a low-intensity light-emitting function.

[0113] Optionally, in addition to a light source configured to emit light in the direction of the liquid crystal element, the optical device also includes one or more additional light sources positioned on at least one side of the optical surface, or optionally on both sides of the optical surface. In this diffuse configuration, light is emitted by the one or more additional light sources, and this light flows through the optical surface acting as a light guide and is reflected on the liquid crystal element, performing a low-intensity light emission function (e.g., a low-intensity signaling function, such as, in particular, a position lamp). Therefore, a second light emission configuration as a signaling light emission configuration can also be used in the optical device according to the invention, wherein the additional light source is arranged laterally relative to the liquid crystal element. This additional light source is added to the light source illuminating the facing liquid crystal element. In the case of such an optical device with lateral illumination, the second light emission configuration can allow the light emitted by the additional light source to be reflected. In this configuration, the optical surface is preferably a layer with a thickness in the range of 1 mm to 6 mm, more preferably 2 mm to 5.5 mm, more preferably 3 mm to 5 mm, and more preferably 3.5 mm to 4.5 mm.

[0114] Alternatively, the signal-emitting configuration is implemented by a light source configured to emit light in the direction of the liquid crystal element at a reduced intensity compared to the intensity used for the illumination configuration (i.e., the transparent configuration, where the liquid crystals of the element are vertically aligned). The light passing through the liquid crystal element (liquid crystal layer) performs a high-intensity signal-emitting function (e.g., for daytime running lights and turn signals).

[0115] Preferably, the illumination configuration corresponds to the transparent configuration.

[0116] Then, the liquid crystal element allows the light required for the illumination function to pass through without blocking the light, thus obtaining a beam of light that meets regulatory requirements.

[0117] Preferably, depending on the configuration of the liquid crystal element, the liquid crystal of the liquid crystal element has no twist corresponding to a twist of 0π, a first twist corresponding to a twist of π, or a second twist corresponding to a twist of 2π.

[0118] No twist, first twist, and second twist are each associated with one of the states exhibited by the liquid crystals, depending on the type of liquid crystal, and thus extended to one or another of the configurations adopted by the liquid crystal element.

[0119] Preferably, in the illumination configuration, the liquid crystals of the liquid crystal element are in a vertically aligned state or in a planar state, and the twist of the liquid crystal in the planar state is 0π.

[0120] The vertical alignment corresponds to the arrangement of liquid crystals relative to each other. The rod-shaped liquid crystals are essentially perpendicular to the electrodes in this state.

[0121] Preferably, the liquid crystal of the liquid crystal element is selected from cholesteric crystals, nematic crystals, and ferroelectric crystals.

[0122] All these types of liquid crystals can have at least two stable states. These liquid crystals are long, thin molecules whose arrangement is controlled by applying a voltage. The arrangement of the liquid crystals is modified according to changes in the amplitude or direction of the electric field. Cholesteric crystals have a helical structure, while nematic crystals have a rod-like structure.

[0123] Preferably, the liquid crystal of the liquid crystal element comprises (more preferably) 1'',7''-bis(4-cyanobiphenyl-4'-yl)heptane (CB7CB). .

[0124] Preferably, alternatively, the liquid crystal of the liquid crystal element comprises (more preferably) a mixture of the following: , , and Preferably, the mixture contains 51% by weight of 25% by weight 16% by weight and 8% by weight The percentage by weight is based on the weight of the mixture.

[0125] Preferably, the liquid crystal of the element is a liquid crystal to which one or more chiral agents can be added. Preferably, based on the weight of the liquid crystal element containing the chiral agent, the content of the agent is in the range of 1% to 6% by weight, preferably 2% to 5.5% by weight, and preferably 3% to 5% by weight.

[0126] According to an optional feature of the invention, the liquid crystal element comprises a dye. The use of a dye is advantageous according to the invention because it allows for broadening of the absorption spectrum and provides color freedom that cannot be obtained solely by adjusting the helical pitch of the cholesteric liquid crystal.

[0127] These dyes are, for example, dichroic dyes. When the liquid crystal element is in its first decorative configuration, these dyes allow the optical surface to be given the desired color. The dyes are oriented within the liquid crystal element in the same way as the liquid crystal, positioning themselves within the space left by the liquid crystal. Furthermore, the dyes follow the changes in the liquid crystal. This results in the dye orientation being substantially the same as the liquid crystal orientation; that is, in the first decorative configuration, the orientation is substantially parallel to the electrodes of the liquid crystal element, and in the second or third light-emitting configuration, the orientation is substantially perpendicular to the electrodes. The movement of the liquid crystal under the influence of an electric field causes the dye to move. It will be understood that, like the liquid crystal, the dyes do not interfere with the propagation of light in the second and third light-emitting configurations.

[0128] According to the invention, there are no limitations on the dyes, as long as they are preferably soluble in liquid crystals, for example, at operating temperatures in the range of -40°C to 100°C. For example, the dye may be a mixture comprising one or more of the following: 4-dimethylamino-4'-nitroazobenzene (DNANAB). , , , , , , , , , , ,and Where X = -C2H5 or -OC5H 11 Or -N(CH3)2 or -C4H9.

[0129] Preferably, the dye allows for the production of black.

[0130] Preferably, based on the weight of the liquid crystal element containing the dye, the dye content in the liquid crystal element is not more than 10% by weight, more preferably not more than 9% by weight, more preferably within the range of 0.5% to 8% by weight, more preferably 1% to 6% by weight, more preferably 1.5% to 5% by weight, and more preferably 2% to 4% by weight.

[0131] In the context of this invention, and not to be bound by any theory, it should be noted that if the dye content is greater than 10% by weight based on the weight of the liquid crystal element containing these dyes, this may adversely affect the illumination in the third light-emitting configuration corresponding to the vertical alignment state of the liquid crystal of the liquid crystal element.

[0132] Preferably, in addition to liquid crystal, the liquid crystal element also comprises one or more polymers. Thus, the liquid crystal is stabilized in a network of one or more polymers. For example, one or more polymers are acrylate polymers. Under these conditions, the element can be referred to as a polymer network-stabilized liquid crystal. If present, the one or more polymers are included in the liquid crystal element in an amount preferably from 1% to 50% by weight, more preferably from 1% to 30% by weight, more preferably from 1% to 10% by weight, and even more preferably from 5% to 10% by weight, based on the weight of the liquid crystal element containing said one or more polymers.

[0133] Advantageously, the liquid crystal element contains between 1% and 10% polymer. Therefore, the liquid crystal element differs from PDLC (polymer-dispersed liquid crystal) films, which have a higher polymer content.

[0134] Preferably, alternatively, the liquid crystal of the liquid crystal element is not dispersed or stabilized in the polymer network.

[0135] Preferably, the optical device includes at least a first section dedicated to a first decorative configuration and a second section dedicated to a second light-emitting configuration.

[0136] The first and second partitions are, for example, partitions of an optical surface. The first partition is dedicated to a first decorative configuration, while the second partition is dedicated to a signal-emitting or illumination-emitting configuration.

[0137] Preferably, the optical device includes multiple addressable parts, each of which is independently controllable.

[0138] Each addressable portion can correspond to a pixel on the optical surface of an optics device. The addressable portions can be controlled using passive matrix addressing techniques. Thus, a portion of the optical surface can be placed or held in a decorative configuration—in other words, in a configuration where light emitted by a light source does not exit—while the entire remaining portion of the optical surface is held or placed in a signaling or illumination configuration—in other words, in a configuration where light emitted by a light source exits the optics device. Where appropriate, this control can allow for the creation of pictograms or animations on the optical surface.

[0139] The present invention also relates to a motor vehicle including the optical device as described above, wherein the optical device is arranged at the front of the motor vehicle.

[0140] Alternatively or additionally, the present invention relates to a motor vehicle that includes the optical device described above, wherein the optical device is arranged at the rear of the motor vehicle.

[0141] In the context of this invention, the term "at least one light source" in the expression "optical device for motor vehicles, the optical device comprising at least one light source" clearly describes the fact that the optical device describes a "light source", and the term "comprising" does not exclude the presence of one or more other light sources.

[0142] In the context of this invention, it should be noted that the dopant may be S5011 or R5011, and the chemical formula of these dopants is C. 32 H 34 O2, where R5011 is the dextrorotatory enantiomer and S5011 is the levorotatory enantiomer.

[0143] The invention is further illustrated by the following set of embodiments and a combination of embodiments derived from the references and backreferences. In particular, it should be noted that in each instance of referring to the scope of embodiments, such as in the context of a statement like "device according to any one of embodiments 1 to 4," each embodiment within that scope is considered to be explicitly disclosed by those skilled in the art; in other words, such a statement should be understood by those skilled in the art to be synonymous with "device according to any one of embodiments 1, 2, 3, and 4." Furthermore, it should be explicitly stated that the following set of embodiments represents a suitably structured portion of the general description of preferred aspects of the invention and therefore appropriately supports, but does not necessarily represent, the claims of the invention.

[0144] According to Embodiment 1 of the present invention, an optical device (4) for a motor vehicle (1) is described, the optical device comprising at least one light source and a liquid crystal element (12). The light source is configured to emit light in the direction of the liquid crystal element (12). The optical device (4) includes a power supply, and the liquid crystal element (12) is capable of displaying: - First decorative configuration (20), in which the liquid crystal element (12) blocks the passage of light, - Second light-emitting configuration (22), in which the light emitted by the light source passes through the liquid crystal element (12), and - Third light-emitting configuration (24), which is different from the second light-emitting configuration (22), in which the light emitted by the light source passes through the liquid crystal element (12). The liquid crystal element (12) changes from one configuration (20, 22, 24) to another configuration according to the instruction that controls the power supply device to generate or not generate voltage.

[0145] Example 2: The optical device (4) according to Example 1 further includes an optical surface (10), wherein the liquid crystal element is interposed between the light source and the optical surface, wherein the optical surface (10) is a layer that allows light emitted by the light source (if present) and light emitted from the outside (where applicable) to pass through.

[0146] Example 3: The optical device (4) according to Example 1 or 2, wherein the first decorative configuration (20) is a reflective configuration, wherein the liquid crystal element (12) not only blocks the passage of light but also reflects light emitted from outside the vehicle (1) by the orientation of the liquid crystal of the element (12).

[0147] Example 4: The optical device (4) according to Example 1 or 2, wherein the first decorative configuration (20) is a colored configuration, wherein the liquid crystal element (12) is colored.

[0148] Example 5: An optical device (4) according to any one of Examples 1 to 4, wherein, in the first decorative configuration (20), the liquid crystal of the liquid crystal element (12) is in a planar state (28).

[0149] Example 6: The optical device (4) according to Example 5, wherein the planar state (28) of the liquid crystal is obtained in the absence of a voltage generated by the power supply device.

[0150] Example 7: An optical device (4) according to any one of Examples 1 to 6, wherein the second light-emitting configuration (22) corresponds to a diffuse configuration.

[0151] Example 8: The optical device (4) according to Example 7, wherein, in the second light-emitting configuration (22), the liquid crystal of the liquid crystal element (12) is at least partially in a focal cone state (30).

[0152] Example 9: The optical device (4) according to Example 8, wherein the focal cone state (30) of the liquid crystal is obtained by applying a pulse voltage, regardless of whether the polarity is changed.

[0153] Example 10: An optical device (4) according to any one of Examples 1 to 9, wherein the third light-emitting configuration (24) corresponds to a transparent configuration.

[0154] Example 11: An optical device (4) according to any one of Examples 1 to 10, wherein, in the third light-emitting configuration (24), the liquid crystal of the liquid crystal element (12) is in a vertically aligned state (32).

[0155] Example 12: The optical device (4) according to Example 11, wherein the vertical alignment state (32) of the liquid crystal is obtained by applying a voltage with a change in polarity, the absolute value of which is constant.

[0156] Example 13: An optical device (4) according to any one of Examples 1 to 12, wherein the liquid crystal of the liquid crystal element (12) is a nematic liquid crystal or a cholesteric liquid crystal (18).

[0157] Example 14: An optical device (4) according to any one of Examples 1 to 13, wherein the liquid crystal element (12) is a layer with a thickness in the range of 10 micrometers to 40 micrometers, preferably 15 micrometers to 30 micrometers.

[0158] Example 15: An optical device (4) according to any one of Examples 1 to 14, wherein the liquid crystal element (12) comprises a dye (26); preferably, wherein, based on the weight of the liquid crystal element (12) comprising the dye, the dye content in the liquid crystal element (12) is not more than 10% by weight, more preferably not more than 9% by weight, more preferably in the range of 0.5% to 8% by weight, more preferably 1% to 6% by weight, more preferably 1.5% to 5% by weight, and more preferably 2% to 4% by weight.

[0159] Example 16: The optical device (4) according to Example 15, wherein the dye (26) is a dichroic dye.

[0160] Example 17: The optical device (4) according to any one of Examples 1 to 17 further includes a second light source (15) configured to emit light, wherein the second light source (15) is laterally positioned relative to the optical surface (10) defined in Example 2.

[0161] Example 18: An optical device (4) according to any one of Examples 1 to 17, wherein the liquid crystal element (12) includes a plurality of addressable portions, each addressable portion being independently controllable.

[0162] Example 19: A motor vehicle (1) includes at least one optical device (4) according to any one of Examples 1 to 18, wherein the optical device (4) is arranged in front of (2) and / or behind the motor vehicle (1).

[0163] Example 20: An optical device (4') for a motor vehicle (1'), the optical device comprising at least one light source and a liquid crystal element (12'). The light source is configured to emit light in the direction of the liquid crystal element (12'). The optical device (4') includes a power supply device capable of generating an electric field to modify the state of the liquid crystal element (12') to place the liquid crystal element in: In a first decorative configuration (20'), the liquid crystal element (12') blocks the passage of light; or The second light-emitting configuration (22') is in which the light emitted by the light source passes through the liquid crystal element (12'), and the liquid crystal (18') is configured to be stable in both configurations (20', 22') in the absence of an electric field generated by the power supply device.

[0164] Example 21: According to the optical device (4') of Example 20, the transition of the liquid crystal element (12') from one configuration to another is achieved by occasionally applying a voltage corresponding to a set value by the power supply device.

[0165] Example 22: The optical device (4') according to Example 20 or 21, wherein the first decorative configuration (20') is a reflective configuration, wherein the liquid crystal element (12') not only blocks the passage of light but also reflects light emitted from outside the vehicle (1') by the orientation of the liquid crystal of the element (12').

[0166] Example 23: An optical device (4') according to any one of Examples 20 to 22, wherein the first decorative configuration (20') is a colored configuration, wherein the liquid crystal element (12) is colored.

[0167] Example 24: An optical device (4') according to any one of Examples 20 to 23, wherein, in the first decorative configuration (20'), the liquid crystal (18') of the liquid crystal element (12') is in a planar state (28').

[0168] Example 25: An optical device (4') according to any one of Examples 20 to 24, wherein the second light-emitting configuration (22') is selected from a signal-emitting configuration and an illumination-emitting configuration.

[0169] Example 26: The optical device (4') according to Example 25, wherein the signal emission configuration corresponds to the diffuse configuration.

[0170] Example 27: The optical device (4') according to Example 25 or 26, wherein, in the signal emission configuration, the liquid crystal (18') of the liquid crystal element (12') is in a focal cone state (30').

[0171] Example 28: An optical device (4') according to any one of Examples 25 to 27, wherein the illumination-emitting configuration corresponds to a transparent configuration.

[0172] Example 29: An optical device (4') according to any one of Examples 20 to 28, wherein, depending on the configuration of the liquid crystal element (12'), the liquid crystal (18') of the liquid crystal element (12') has no twist corresponding to a twist of 0π, a first twist (34') corresponding to a twist of π, or a second twist (36') corresponding to a twist of 2π.

[0173] Example 30: An optical device (4') according to any one of Examples 25 to 28 in conjunction with Examples 24 and 29, wherein, in the illumination configuration, the liquid crystal (18') of the liquid crystal element (12') is in a vertically aligned state (32') or in the planar state (28'), and the twist of the liquid crystal (18') in the planar state is 0π.

[0174] Example 31: An optical device (4') according to any one of Examples 20 to 30, wherein the liquid crystal (18') of the liquid crystal element (12') is selected from cholesteric crystals, nematic crystals and ferroelectric crystals.

[0175] Example 32: An optical device (4') according to any one of Examples 20 to 31, wherein the liquid crystal element (12') is a layer with a thickness in the range of 10 micrometers to 40 micrometers, preferably 15 micrometers to 30 micrometers.

[0176] Example 33: An optical device (4') according to any one of Examples 20 to 32, wherein the liquid crystal element (12') comprises a dye (26').

[0177] Example 34: The optical device (4') according to Example 33, wherein the dye is a dichroic dye.

[0178] Example 35: The optical device (4') according to Example 33 or 34, wherein, based on the weight of the liquid crystal element (12') containing the dye, the dye content in the liquid crystal element (12') is not more than 10% by weight, preferably not more than 9% by weight, more preferably from 0.5% to 8% by weight, more preferably from 1% to 6% by weight, more preferably from 1.5% to 5% by weight, and more preferably from 2% to 4% by weight.

[0179] Example 36: The optical device (4') according to any one of Examples 20 to 35 further includes an optical surface (10'), wherein the liquid crystal element is inserted between the light source and the optical surface, and the light-emitting configuration is visible on the optical surface.

[0180] Example 37: The optical device (4') according to Example 36 further includes a second light source (15'), which is configured to emit light, wherein the second light source (15') is laterally positioned relative to the optical surface (10').

[0181] Example 38: The optical device (4') according to any one of Examples 20 to 37 includes a plurality of addressable portions, each of which is independently controllable.

[0182] Example 39: A motor vehicle (1') includes at least one optical device (4') according to any one of Examples 30 to 38, wherein the optical device (4') is arranged in front of (2') and / or behind the motor vehicle (1').

[0183] Other features, details, and advantages of the invention will become clearer, on the one hand, by reading the following description, and on the other hand, by referring to the examples of embodiments provided in a non-limiting manner with reference to the accompanying drawings, in which: [ Figure 1 The diagram schematically shows the front of a motor vehicle including an optical device (first optical device) according to the invention; [ Figure 2 The optical device (first optical device) according to the present invention is schematically shown, which has a liquid crystal element inserted between the light source and the light emitting surface; [ Figure 3 ]Schematic illustration Figure 1 Different liquid crystal states of liquid crystal elements in optical devices; [ Figure 4 ]Schematic illustration Figure 1 Another view of the different liquid crystal states of the liquid crystal element in the optical device; [ Figure 5 ]Schematic illustration Figure 1 Two different liquid crystal states of liquid crystal elements in optical devices, wherein dyes are added to the liquid crystal elements; [ Figure 6 The diagram schematically shows the front of a motor vehicle including an optical device (second optical device) according to the invention; [ Figure 7 The optical device (second optical device) according to the present invention is schematically shown, which has a liquid crystal element inserted between the light source and the light emitting surface; [ Figure 8 ]Schematic illustration Figure 6 A first embodiment of a liquid crystal element for an optical device, wherein the liquid crystal of the liquid crystal element has different states; [ Figure 9 This schematically illustrates a second embodiment of the liquid crystal element of the optical device (second optical device) of the present invention; [ Figure 10 This schematically illustrates a third embodiment of the liquid crystal in the liquid crystal element of the optical device (second optical device) of the present invention; [ Figure 11 ]Schematic illustration Figure 6 Two different liquid crystal states of liquid crystal elements in optical devices, wherein dyes are added to the liquid crystal elements.

[0184] The features, variations, and various embodiments of the present invention can be combined with each other in various combinations, provided that they are not mutually incompatible or mutually exclusive. In particular, it is conceivable that variations of the invention may include only features selected separately from the other features described below, provided that such selection of features is sufficient to impart technical advantages and / or distinguish the invention from the prior art.

[0185] In the accompanying drawings, elements that appear in more than one drawing are indicated by the same reference numerals in all of them.

[0186] therefore, Figure 1 A motor vehicle 1 according to the invention is schematically shown. The motor vehicle 1 is shown here in a previous view. The motor vehicle includes a front end 2, which is equipped with an optical element 4 according to the invention. Although the optical element 4 is shown here on the front end 2 of the motor vehicle 1, alternative embodiments in which the optical element 4 is mounted on the rear end of the motor vehicle 1, on both the front end 2 and the rear end of the motor vehicle, or on a side of the vehicle (e.g., its side door) are contemplated without departing from the scope of the invention.

[0187] Optical device 4 performs both at least one decorative function and at least one light-emitting function in motor vehicle 1. More specifically, optical device 4 allows for the implementation of a decorative function, a first light-emitting function, and a second light-emitting function, which are separate. For this purpose, on the front 2 of motor vehicle 1, optical device 4 includes an optical surface 10 that forms an interface with the exterior of motor vehicle 1, and is thus visible to other road users or pedestrians around motor vehicle 1. In other words, light emitted by the optical device for implementing the first or second light-emitting function exits through the optical surface 10, and the decorative function is performed on the optical surface. More specifically, at least one section of the optical surface allows for the implementation of both light-emitting and decorative functions; it should be understood that the optical surface may include sections that allow only one of the light-emitting or decorative functions to be implemented.

[0188] As will be described in detail, the optical surface is divided into such partitions or such partitions correspond to the presence of a liquid crystal optical element 12 on the optical surface and opposite such partitions or such partitions. For example, in the example shown, the optical element 4 is configured such that the first partition 6 of the optical surface 10 is dedicated to performing a decorative function alone, and the second partition 8 of the optical surface 10 is dedicated to performing both a decorative function and a light-emitting function.

[0189] Alternatively, each light-emitting function can be associated with a specific partition of the optical surface, provided that, according to the invention, these specific partitions are oriented toward the liquid crystal element, as will be described below, wherein the liquid crystal is capable of exhibiting three stable configurations depending on the electric field applied thereto.

[0190] In this case, the first light-emitting function corresponds to the signaling function (e.g., indicating a change of direction) or position light of the motor vehicle 1, while the second light-emitting function corresponds to the illumination function, such as low beam or high beam.

[0191] exist Figure 2 The diagram schematically illustrates an optical device 4 arranged in the second partition 8. The optical device includes a light-emitting device 5, represented in this case as a housing, one surface of which includes a lens 7 for projecting a light beam formed by light emitted from light-emitting diodes arranged on a printed circuit board represented by the light-emitting device 5. The form of the light-emitting device is given as an indication and may consist only of light-emitting diodes and a printed circuit board. In this case, for simplicity and without implying any limitation, the light-emitting device 5 is a light source 5.

[0192] In addition, Figure 2The image shows a second light source 15, which is configured to emit light that is reflected and / or transmitted by the liquid crystal element. Unlike the light source 5, which is positioned facing the element 12, the second light source 15 is laterally positioned relative to the optical surface 10 and the liquid crystal element 12.

[0193] Optical device 4 further includes liquid crystal element 12, which in Figures 3 to 5 As shown in the diagram, the liquid crystal element 12 is interposed between the light source and the optical surface 10. The optical device 4 further includes a power supply device 9, which can be controlled to generate an electric field within the liquid crystal element. Similar to the power supply devices used for the light source, these power supply devices can be carried on a printed circuit board.

[0194] The light source is configured to emit light in the direction of the liquid crystal element 12, such that when the liquid crystal element is in a configuration that allows light to pass through, the light passes through the liquid crystal element 12, and then passes through the optical surface 10 and leaves the motor vehicle 1.

[0195] The liquid crystal element 12 (= liquid crystal layer) is, for example, a film. In this case, the liquid crystal element is defined by a first electrode 14 and a second electrode 16, which are substantially parallel to each other, and liquid crystal is disposed between the first electrode and the second electrode. These liquid crystals are, for example, cholesteric liquid crystal 18. In some embodiments, in addition to cholesteric liquid crystal 18, the liquid crystal element 12 also includes a polymer interposed between the electrodes. The two electrodes 14, 16 are substantially parallel to each other. In some embodiments, a light-emitting diode constituting the light-emitting device 5 is disposed on the edge of the liquid crystal element 12, that is, between the first plane where the first electrode 14 is located and the second plane where the second electrode 16 is located.

[0196] The liquid crystal element 12 is configured to either block or allow light emitted from a light source to pass through. For this purpose, the liquid crystal element 12 is configured to present various configurations that block or allow light to pass through. More specifically, the liquid crystal element 12 is configured to present: a first decorative configuration 20, in which the liquid crystal element blocks light, for example, from outside the optical device 4; or a second light-emitting configuration 22, in which light emitted by the light source passes through the liquid crystal element; or a third light-emitting configuration 24, in which light also passes through the liquid crystal element. Figure 3 and Figure 4 The three configurations 20, 22, and 24 are shown. In some specific embodiments, the optics 4 includes an additional light source that emits light laterally relative to the liquid crystal element 12, while conversely, light from the aforementioned light source is emitted in front of the liquid crystal element 12. In a second configuration, the light emitted by the additional light source can be transmitted and / or reflected by the liquid crystal element 12. There is optical contact between the liquid crystal element 12 and the optical surface 10.

[0197] In the example shown, the first decorative configuration 20 of the liquid crystal element 12 corresponds to the decorative function of the optical device 4, the second light-emitting configuration 22 corresponds to the signal emission function of the optical device, and the third light-emitting configuration 24 corresponds to the illumination function of the optical device.

[0198] As described above, these decorative functions and these light-emitting functions (generated by specific configurations of liquid crystal elements in their respective free localities) can be implemented alternately across the entire optical surface, or in dedicated sections of the optical surface. For example, the first section 6 of the optical surface is dedicated to the first decorative function 20, while the second section 8 of the optical surface allows for the implementation of each of configurations 20, 22, and 24. Therefore, the front end 2 of the motor vehicle 1 can perform multiple functions.

[0199] In this context, the liquid crystal element 12 may include addressable portions facing each of the first partition 6 and the second partition 8. These addressable portions of the liquid crystal element 12 each correspond to a pixel of the optical surface 10. The addressable portions of the liquid crystal element 12 can be advantageously controlled by passive matrix addressing techniques to precisely control the creation of pictograms on the optical surfaces 10 of the first two partitions.

[0200] Depending on the embodiment, the first decorative configuration 20 corresponds to a reflective configuration or a colored configuration. In the case of a reflective configuration, the optical surface 10 has a mirror appearance. In the case of a colored configuration, the optical surface 10 has one or more colors; for example, the optical surface is black.

[0201] When the liquid crystal element 12 contains dye 26 in addition to cholesteric liquid crystal 18, a coloring configuration of the first decorative configuration 20 is obtained. Figure 5 The diagram shows a dye 26 located in the cholesteric liquid crystal 18 between the first electrode 14 and the second electrode 16 of the liquid crystal element 12. These dyes 26 are, for example, dichroic dyes.

[0202] The second light-emitting configuration 22 of the liquid crystal element 12 corresponds to a diffuse configuration. The diffuse aspect corresponds to splitting the light rays propagating in a direction tilted relative to the optical axis of the optical device, thereby broadening the beam while maintaining a uniform beam. As described above, when an additional light source emits light laterally relative to the liquid crystal element 12, the second light-emitting configuration 22 may correspond to a diffuse configuration or a reflective configuration, or even allow for light decoupling in the case of guiding light.

[0203] Finally, the third light-emitting configuration 24 coincides with the transparent configuration of the liquid crystal element 12. This transparent configuration allows for the avoidance of interference with the light sources involved in the illumination function, which must meet specific regulatory requirements.

[0204] Each of these configurations of the liquid crystal element 12 depends on the orientation of the cholesteric liquid crystal 18 constituting the liquid crystal element. Reference will now be made to... Figures 3 to 5 This orientation of cholesteric liquid crystal 18 is described.

[0205] Cholesteric liquid crystals 18 can move between several states within the liquid crystal element 12. More specifically, the orientation and states of these cholesteric liquid crystals 18 depend on the electric field generated by the power supply device, particularly the voltage. As will be understood from the above, the liquid crystal element 12 is regulated according to the electric field generated by the power supply device. The presence or absence of (and, where applicable, voltage) changes one configuration 20, 22, 24 to another.

[0206] In the first decorative configuration 20, the cholesteric liquid crystals 18 of the liquid crystal element 12 are in a planar state 28, in which the cholesteric liquid crystals are oriented at least partially parallel to the electrodes 14, 16 of the liquid crystal element 12. The planar state of the cholesteric liquid crystals 18 is obtained without applying an electric field, such that the planar state corresponds to the standard state of the cholesteric liquid crystals 18, and in this respect, the planar state corresponds to the deactivated or off state of the optical device 4.

[0207] In this first decorative configuration 20, the dyes 26 have the same orientation as the liquid crystal (e.g., cholesteric liquid crystal 18). Specifically, these dyes 26 are long molecules that are simultaneously reoriented with the cholesteric liquid crystal 18 and driven by the cholesteric liquid crystal within the liquid crystal element 12 (guest-host effect). Figure 5 This reorientation of dye 26 is shown in the figure.

[0208] In the second light-emitting configuration 22 of the liquid crystal element 12, its cholesteric liquid crystal 18 is in a focal conic state 30. This focal conic state 30 can be specifically obtained by applying a pulsed voltage (without changing its polarity). The voltage can be maintained in its pulsed form, i.e., stabilized in this form, by a specific control mode of the power supply device. For example, in the focal conic state 30 of the cholesteric liquid crystal, the pulses in the voltage can appear at a frequency between zero and several hundred Hz. These pulses in the voltage are separated from each other by a plateau segment of 0 V.

[0209] In the third light-emitting configuration 24, the cholesteric liquid crystal 18 of the liquid crystal element 12 is in a vertical alignment state 32. More specifically, the cholesteric liquid crystal 18 is parallel to the direction of the electric field, which makes it possible to obtain a transparent configuration. For example, this vertical alignment state 32 of the cholesteric liquid crystal 18 is generated by a power supply device applying a voltage with a constant absolute value within the optical device 4. This voltage has a constant absolute value but is controlled to undergo rapid polarity changes, for example, at a frequency of 50 Hz, typically between 30 Hz and 100 Hz. The polarity changes do not include a plateau segment of 0 V.

[0210] Figure 3 and Figure 4 More specifically, the cholesteric liquid crystal 18 is shown changing from one state 28, 30, 32 to another state, and extendedly, the liquid crystal element 12 is shown changing from one configuration of its configuration 20, 22, 24 to another configuration.

[0211] Figure 3 The transition from vertical alignment state 32 to transient planar state, then to focal cone state 30, and then to planar state 28 is illustrated. Figure 3 More specifically, corresponding to the spontaneous relaxation of the cholesteric liquid crystal 18 when the electric field is removed, the cholesteric liquid crystal 18 then adopts its planar state 28, which corresponds to the off state of the optical device 4. Alternatively, the cholesteric liquid crystal 18 can be returned to the planar state by heating the optical device 4, and more specifically by heating the liquid crystal element.

[0212] Similarly, Figure 4 The transitions from planar state 28 to focal conic state 30, from focal conic state 30 to vertical alignment state 32, then from vertical alignment state 32 to transient planar state, and finally from transient planar state back to planar state 28 are shown, with the state changes depending on the electric field applied by the power supply device. Although not described here, the cholesteric liquid crystal 18 can take on states other than planar state 28, focal conic state 30, vertical alignment state 32, and transient planar state, so that the liquid crystal element 12 changes from one configuration 20, 22, 24 to another configuration.

[0213] As described above, during the transition from one configuration 20, 22, 24 to another, the electric field reorients the cholesteric liquid crystal 18, which in turn drives the dye molecules 26 when they are provided in the liquid crystal element 12; in other words, the reorientation of the cholesteric liquid crystal 18 causes the reorientation of the dye 26, as in Figure 5 It can be seen in the image.

[0214] As can be clearly seen from the above, the device of the present invention (the first device) achieves the set objective by providing an optical device configured to perform decorative functions and at least two different light-emitting functions in the same compartment of a motor vehicle.

[0215] As a reminder, in the accompanying drawings, elements that appear in more than one drawing are indicated by the same reference numerals in all drawings.

[0216] therefore, Figure 6A motor vehicle 1' according to the invention is schematically shown. The motor vehicle 1' is shown here in a previous view. The motor vehicle includes a front end 2' equipped with an optical element 4' according to the invention. Although the optical element 4' is shown here on the front end 2' of the motor vehicle 1', alternative embodiments in which the optical element 4' is mounted on the rear end of the motor vehicle 1', or on both the front end 2' and the rear end of the motor vehicle, are contemplated without departing from the scope of the invention.

[0217] Optical device 4' performs at least both decorative and light-emitting functions in motor vehicle 1'. For this purpose, on the front 2' of motor vehicle 1', optical device 4' includes an optical surface 10' that forms an interface with the exterior of motor vehicle 1', and is thus visible to other road users or pedestrians around motor vehicle 1'. In other words, light emitted by the optical device for performing the light-emitting function exits through the optical surface 10', and the decorative function is performed on the optical surface. More specifically, at least one partition of the optical surface allows for both light-emitting and decorative functions; it should be understood that the optical surface may include partitions that allow only one of the light-emitting and decorative functions to be performed. As will be described in detail, dividing the optical surface into such partitions or such partitions corresponds to the presence of a liquid crystal optical element 12' opposite the optical surface and such partitions or such partitions. For example, in the example shown, optical device 4' is configured such that a first partition 6' of the optical surface 10' is dedicated solely to performing the decorative function, and a second partition 8' of the optical surface 10' is dedicated to performing both the decorative and light-emitting functions.

[0218] In this case, the light-emitting function corresponds to the signaling function (e.g., indicating a change of direction) or position light of the motor vehicle 1', or to the lighting function, such as low beam or high beam.

[0219] The luminescent and decorative functions can be associated with the same or different sections of the optical surface, provided that, according to the invention, these specific sections face the liquid crystal element, as will be described below, wherein the liquid crystal is capable of exhibiting a configuration that remains stable for a moment after the electric field has stopped under the influence of an appropriate electric field.

[0220] exist Figure 7 The optical element 4' is schematically shown. The optical element includes a light-emitting device 5', which is represented in this case as a housing. One surface of the light-emitting device includes a lens 7' for projecting a light beam formed by light emitted from light-emitting diodes arranged on a printed circuit board. The form of the light-emitting device is given as an indication and may consist only of light-emitting diodes and a printed circuit board. Furthermore, in Figure 7The image shows a second light source 15', which is configured to emit light reflected and / or transmitted by the liquid crystal element 12'. Unlike the light source 5', which is positioned facing the element 12', the second light source 15' is laterally positioned relative to the optical surface 10' and the liquid crystal element 12'.

[0221] Optical device 4' further includes liquid crystal element 12', which liquid crystal element in Figures 8 to 10 As shown in the diagram, the liquid crystal element 12' is inserted between the light source and the optical surface 10'. The optical device 4' further includes a power supply device 9', which can be controlled to generate an electric field within the liquid crystal element. Similar to power supplies for light sources, these power supplies can be carried on a printed circuit board.

[0222] The light source is configured to emit light in the direction of the liquid crystal element 12', such that when the liquid crystal element is in a configuration that allows light to pass through, the light passes through the liquid crystal element 12', then through the optical surface 10' and exits the motor vehicle 1'.

[0223] The liquid crystal element 12' is, for example, a film. In this case, the liquid crystal element is defined by a first electrode 14' and a second electrode 16', which are parallel to each other, and the liquid crystal 18' is disposed between the first electrode and the second electrode. In some embodiments, the light-emitting diode constituting the light-emitting device 5' is arranged facing the edge of the liquid crystal element 12', in other words, between the first plane where the first electrode 14' is located and the second plane where the second electrode 16' is located. The liquid crystal is particularly a cholesteric liquid crystal 18', a nematic liquid crystal 18', or a ferroelectric liquid crystal 18'. In addition to the liquid crystal 18', the liquid crystal element 12' also contains chiral agents, which are optically active substances or inducers. For example, the liquid crystal element 12' may contain a dopant, such as S5011, at a concentration of 4.5% by weight based on the weight of the liquid crystal element containing the dopant. In variant embodiments, the liquid crystal element 12' further contains a polymer.

[0224] The liquid crystal element 12' is configured to either block or allow light emitted from a light source to pass through. For this purpose, the liquid crystal element 12' is configured to present various configurations that block or allow light to pass through. More specifically, the liquid crystal element 12' is configured to present: a first decorative configuration 20', in which the liquid crystal element blocks the passage of light; or a second light-emitting configuration 22', in which light emitted by the light source passes through the liquid crystal element. Figures 8 to 10 The two configurations, 20' and 22', are shown in the figure.

[0225] The first decorative configuration 20' of the liquid crystal element 12' corresponds to the decorative function of the optical device 4', and the second light-emitting configuration 22' corresponds to the signal emission function or the illumination emission function of the optical device.

[0226] As described above, this decorative function and this light-emitting function (generated by specific configurations of liquid crystal elements in each free locality) can be implemented alternately across the entire optical surface, or in dedicated sections of the optical surface. For example, the first section 6' of the optical surface may be dedicated to the decorative function, while the second section 8' may allow for the implementation of each of these functions. Thus, the front 2' of the motor vehicle 1' can simultaneously implement both decorative and light-emitting functions; for example, pictograms may be displayed in the first section 6', while the second section 8' performs a signaling function.

[0227] In this context, the optical element 4' may include addressable portions in the first partition 6' and the second partition 8'. These addressable portions each correspond to a pixel on the optical surface 10'. The addressable portions can be controlled using passive matrix addressing techniques to precisely control the creation of pictograms on the optical surface 10' of the front 2'.

[0228] Depending on the embodiment, the first decorative configuration 20' corresponds to a reflective configuration, a colored configuration, or a fully absorptive configuration. In the case of a reflective configuration, the optical surface 10' has a mirror appearance. In the case of a colored configuration, the optical surface 10' has one or more colors; for example, the optical surface is black.

[0229] When, in addition to liquid crystal 18', liquid crystal element 12' also contains dye 26', a coloring configuration of the first decorative configuration 20' is obtained. Figure 11 The diagram shows a dye 26' located in the liquid crystal 18' between the first electrode 14' and the second electrode 16' of the liquid crystal element 12'. These dyes 26' are, for example, dichroic dyes.

[0230] The second light-emitting configuration 22' of the liquid crystal element 12' corresponds to either a diffuse configuration or a transparent configuration. When performing a signal emission function, the second light-emitting configuration 22' corresponds to the diffuse configuration. Therefore, the light can be uniformly distributed across the entire optical surface 10' of the optical device 4'. Conversely, when performing an illumination emission function, the second light-emitting configuration 22' coincides with the transparent configuration of the liquid crystal element 12'. This transparent configuration allows interference with the light involved in the illumination emission function to be avoided, as these light rays must meet specific regulatory requirements.

[0231] Each of these configurations of the liquid crystal element 12' depends on the orientation of the liquid crystal 18' that constitutes the liquid crystal element. Reference will now be made to... Figures 8 to 11 This orientation of the liquid crystal 18' is described.

[0232] Liquid crystals 18' can move between several states within liquid crystal element 12'. More specifically, the orientation and state of these liquid crystals 18' depend on the electric field generated by the power supply device, particularly the amplitude and / or direction and / or shape of that electric field. As will be understood from the above, the liquid crystal element 12' is controlled by the electric field generated by the power supply device. The amplitude changes from one configuration 20', 22' to another, which will be described in detail below.

[0233] In the first decorative configuration 20', the liquid crystals 18' of the liquid crystal element 12' are in a planar state 28', in which the liquid crystals are oriented at least partially parallel to the electrodes 14' and 16' of the liquid crystal element 12'. The planar state of the liquid crystals 18' is obtained without applying an electric field, and therefore this planar state corresponds to the deactivated state of the optical device 4'. Thus, the first decorative configuration 20' is the deactivated state of the optical device 4'.

[0234] In this first decorative configuration 20', the dyes 26' have the same orientation as the liquid crystal 18'. Specifically, these dyes 26' are long molecules that, along with the liquid crystal 18', are simultaneously reoriented and driven by the liquid crystal within the liquid crystal element 12' (guest-host effect). Figure 11 This reorientation of dye 26' is shown in the figure.

[0235] In the second light-emitting configuration 22' of the liquid crystal element 12', its liquid crystal 18' is in either a focal conic state 30' or a vertically aligned state 32'. For some types of liquid crystal 18', the focal conic state 30' corresponds to a diffuse configuration, i.e., a signal emission function, while the vertically aligned state 32' corresponds to a transparent configuration, i.e., an illumination function.

[0236] As described above, the liquid crystal element 12' transitions from one configuration 20', 22' to another configuration based on an electric field. More specifically, the transition from one configuration 20', 22' to another configuration is achieved by the power supply device occasionally applying a voltage. This occasional application corresponds to applying a voltage of a given or set value, which varies depending on whether it is desired to change from the first decorative configuration 20' to the second light-emitting configuration 22' or vice versa. Apart from this occasional application, the power supply device does not generate a continuous voltage. It should be understood that it is not necessary to maintain an electric field to maintain one or the other configuration of 20', 22'.

[0237] Figure 8 A first embodiment is shown, in which the liquid crystal 18' of the liquid crystal element 12' is a cholesteric liquid crystal 18'. Figure 8The transitions from planar state 28' to focal conic state 30', from focal conic state 30' to vertical alignment state 32', then from vertical alignment state 32' to transient planar state, and finally from transient planar state back to planar state 28' are shown, with the state changes depending on the set value of the voltage applied by the power supply device. Although not described here, the liquid crystal 18' can take states other than planar state 28', focal conic state 30', vertical alignment state 32', and transient planar state, so that the liquid crystal element 12' changes from one configuration 20', 22' to another configuration.

[0238] As described above, during the transition from one configuration 20', 22' to another, the electric field reorients the liquid crystals 18', which in turn drive the dye molecules 26'; in other words, the reorientation of the liquid crystals 18' causes the reorientation of the dyes 26', as in Figure 11 It can be seen in the image.

[0239] By utilizing the stability of the state of the liquid crystal 18' in the liquid crystal element 12', the first decorative configuration 20' and the second light-emitting configuration 22' are maintained in the absence of a continuous voltage. Reference will now be made to... Figure 9 and Figure 10 These figures describe this stability and correspond to the second and third embodiments, respectively. These two embodiments are described here with respect to the nematic liquid crystal 18', but the stable state of the cholesteric or ferroelectric liquid crystal 18' can also be modified as necessary to implement the first decorative function 20' and the second light-emitting function 22'.

[0240] The nematic liquid crystals 18' can exhibit different orientations depending on the value of the occasionally applied voltage; therefore, the arrangement of these nematic liquid crystals 18' between the first electrode 14' and the second electrode 16' can exhibit a twist. According to an embodiment, the nematic liquid crystals 18' have an untwisted 34' corresponding to 0π, or a first twist 36' equivalent to a twist of π, or a second twist 38' equivalent to a twist of 2π. For example, a twist of π corresponds to a 180° twist between the nematic liquid crystal 18' closest to the first electrode 14' and the nematic liquid crystal 18' closest to the second electrode 16'.

[0241] exist Figure 9 In the second embodiment shown, a 2π twist corresponds to the first decorative configuration 20' of the liquid crystal element 12', while a 0π twist corresponds to the second light-emitting configuration 22'. More specifically, the second light-emitting configuration 22' is a transparent configuration in this case. Therefore, 0π and 2π twists are stable states of the nematic liquid crystal 18' in this case. It should be noted that in other embodiments, the implementation of the transparent configuration may involve other types of liquid crystals 18' having a π or 2π twist.

[0242] In this case, the twist π corresponds to an intermediate state of the nematic liquid crystal 18'. If the occasional application of voltage from this intermediate state is sudden, in other words, if the electric field is suddenly removed, the nematic liquid crystal 18' adopts a twist of 2π. Conversely, if the occasional application of voltage is gradual, in other words, if the electric field is gradually removed, the nematic liquid crystal 18' adopts a twist of 0π. Therefore, if the electric field is suddenly removed from the intermediate state, the liquid crystal element exhibits its first decorative configuration 20', while if the electric field is gradually removed, the liquid crystal element 12' exhibits a transparent light-emitting configuration that allows for illumination.

[0243] The nematic liquid crystal 18' will naturally return to an intermediate state from one of the twists 0π and 2π. This return occurs, for example, two to three seconds after a stable state is achieved. Where appropriate, a refresh voltage can be applied to maintain the stable state for a period of time longer than two or three seconds.

[0244] exist Figure 10 In the third embodiment, when the nematic liquid crystals 18' have a twist of 0π, they enable a first decorative configuration 20' of the liquid crystal element 12' to be obtained, and these nematic liquid crystals 18' enable a second light-emitting configuration 22' to be obtained with a twist of π. This second light-emitting configuration 22' specifically corresponds to a diffuse configuration, which allows for the implementation of signal emission functions.

[0245] In this third embodiment, if the occasional application of voltage, starting from an intermediate state of the nematic liquid crystal 18', is sudden—in other words, if the electric field is suddenly removed—the nematic liquid crystal 18' exhibits a twisted π. Conversely, if the occasional application of voltage is gradual—in other words, if the electric field is gradually removed—the nematic liquid crystal 18' exhibits a twisted 0π. Therefore, if the electric field is suddenly removed from an intermediate state, the liquid crystal element 12' exhibits its diffuse emission configuration, while if the electric field is gradually removed, the liquid crystal element 12' exhibits a first decorative configuration 20'.

[0246] As clearly seen above, the optical device (second device) of the present invention achieves the set objectives by providing an optical device configured to perform decorative and light-emitting functions in the same compartment of a motor vehicle. Furthermore, this compartment, due to its high contrast, is suitable for projecting information to people around the motor vehicle. These two functions of the optical device are achieved through the stable configuration of the liquid crystal elements of the optical device, which allows one or more of these functions to be implemented in the absence of a sustained electric field, thereby producing an energy-saving effect.

[0247] However, the invention is not limited to the devices and configurations described and shown herein, but extends to any equivalent devices and configurations and any technically feasible combinations of such devices.

Claims

1. An optical device (4) for a motor vehicle (1), the optical device comprising at least one light source and a liquid crystal element (12). The light source (5) is configured to emit light in the direction of the liquid crystal element (12). The optical device (4) includes a power supply, and the liquid crystal element (12) is capable of displaying: - First decorative configuration (20), in which the liquid crystal element (12) blocks the passage of light, - Second light-emitting configuration (22), in which the light emitted by the light source passes through the liquid crystal element (12), and - Third light-emitting configuration (24), which is different from the second light-emitting configuration (22), in which the light emitted by the light source passes through the liquid crystal element (12). The liquid crystal element (12) changes from one configuration (20, 22, 24) to another configuration according to the instruction that controls the power supply device to generate or not generate voltage.

2. The optical device (4) as claimed in claim 1, further comprising an optical surface (10), wherein the liquid crystal element (12) is located between the optical surface (10) and the light source (5), wherein, The optical surface (10) is a layer that allows light emitted by the light source to pass through the second light-emitting configuration (22) and the third light-emitting configuration (24) and allows light emitted from the outside to pass through the first decorative configuration (20).

3. The optical device (4) as described in claim 1 or 2, wherein, The first decorative configuration (20) is a reflective configuration, wherein the liquid crystal element (12) not only blocks the passage of light but also reflects light emitted from outside the vehicle (1) by the orientation of the liquid crystal of the element (12).

4. The optical device (4) as claimed in claim 1, wherein, The first decorative configuration (20) is a colored configuration, wherein the liquid crystal element (12) is colored.

5. The optical device (4) as described in any one of claims 1 to 4, wherein, In the first decorative configuration (20), the liquid crystal of the liquid crystal element (12) is in a planar state (28), wherein the planar state (28) of the liquid crystal is obtained in the absence of a voltage generated by the power supply device.

6. The optical device (4) as claimed in any one of claims 1 to 5, wherein, In the second light-emitting configuration (22), the liquid crystal of the liquid crystal element (12) is at least partially in a focal cone state (30).

7. The optical device (4) as claimed in claim 6, wherein, The focal cone state (30) of the liquid crystal is obtained by applying a pulse voltage, regardless of whether the polarity is changed.

8. The optical device (4) as claimed in any one of claims 1 to 7, wherein, The third light-emitting configuration (24) corresponds to the transparent configuration, wherein, in the third light-emitting configuration (24), the liquid crystals of the liquid crystal element (12) are in a vertically aligned state (32).

9. The optical device (4) as claimed in claim 8, wherein, The vertical alignment state (32) of the liquid crystal is obtained by applying a voltage with a change in polarity, the absolute value of which is constant.

10. The optical device (4) in conjunction with any one of claims 2 to 9, further comprising a second light source (15) configured to emit light, wherein, The second light source (15) is laterally positioned relative to the optical surface (10).

11. The optical device (4) as described in the preceding claim, wherein, The liquid crystal element (12) is configured to present a second light-emitting configuration corresponding to a diffuse configuration, wherein the second light source (15) is activated to emit light into the optical surface (10) which serves as a light guide and is in contact with the liquid crystal element, and the light flowing through the optical surface is reflected on the liquid crystal element and passes through the optical surface to reach the outside, thereby performing a low-intensity light-emitting function.

12. The optical device (4) as claimed in any one of claims 1 to 11, wherein, The liquid crystal of the liquid crystal element (12) is a nematic liquid crystal or a cholesteric liquid crystal (18).

13. The optical device (4) as claimed in any one of claims 1 to 12, wherein, The liquid crystal element (12) is a layer with a thickness ranging from 10 micrometers to 40 micrometers, preferably from 15 micrometers to 30 micrometers.

14. The optical device (4) as claimed in any one of claims 1 to 13, wherein, The liquid crystal element (12) contains a dye.

15. The optical device (4) as described in the preceding claim, wherein, The dye is a dichroic dye.

16. The optical device (4) as claimed in claim 14 or 15, wherein, Based on the weight of the liquid crystal element (12) containing the dye, the dye content in the liquid crystal element (12) is not more than 10% by weight, preferably not more than 9% by weight, more preferably between 0.5% and 8% by weight, more preferably between 1% and 6% by weight, more preferably between 1.5% and 5% by weight, and more preferably between 2% and 4% by weight.

17. The optical device (4) as claimed in any one of claims 1 to 16, wherein, The liquid crystal element (12) includes multiple addressable portions, each of which is independently controllable.

18. An optical device (4') for a motor vehicle (1'), the optical device comprising at least one light source and a liquid crystal element (12'). The light source is configured to emit light in the direction of the liquid crystal element (12'). The optical device (4') includes a power supply device capable of generating an electric field to modify the state of the liquid crystal element (12') to place the liquid crystal element in: a first decorative configuration (20') in which the liquid crystal element (12') blocks the passage of light; or The second light-emitting configuration (22') is in which the light emitted by the light source passes through the liquid crystal element (12'). The liquid crystal (18') is configured to be stable in both configurations (20', 22') in the absence of an electric field generated by the power supply device.

19. The optical device (4') as claimed in claim 18, wherein, The transition of the liquid crystal element (12') from one configuration to another is achieved by the power supply device occasionally applying a voltage corresponding to a set value.

20. The optical device (4') as claimed in claim 18 or 19, wherein, In the first decorative configuration (20'), the liquid crystal (18') of the liquid crystal element (12') is in a planar state (28').

21. The optical device (4') as claimed in any one of claims 18 to 20, wherein, The second light-emitting configuration (22') is selected from the signal-emitting configuration and the illumination-emitting configuration.

22. The optical device (4') as claimed in any one of claims 18 to 21, wherein, Depending on the configuration of the liquid crystal element (12'), the liquid crystal (18') of the liquid crystal element (12') has no twist corresponding to a twist of 0π, a first twist (34') corresponding to a twist of π, or a second twist (36') corresponding to a twist of 2π.

23. The optical device (4') as claimed in any one of claims 18 to 22, wherein, The liquid crystal element (12') contains dye.

24. A motor vehicle (1), comprising At least one optical device (4) as described in any one of claims 1 to 17, wherein, The optical device (4) is arranged in front of (2) and / or behind the motor vehicle (1); or At least one optical device (4') as claimed in any one of claims 18 to 23, wherein the optical device (4') is arranged in front of (2') and / or behind the motor vehicle (1').

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