Light projection system for a vehicle

Abstract

The invention concerns a light projection system (100) for a vehicle, comprising a light source unit (110) and a primary lens (120). The light source unit (110) comprises a light emitting surface emitting light beams (200) comprising direct light beams (210) and diffused light beams (220). The primary lens (120) comprises an optical axis (D), a light-entry lens surface (121) facing the light source unit (110) and a light-exit lens surface (122). The light-entry lens surface (121) comprises at least one non-transparent region (123) and at least one transparent region (124). The non-transparent region (123) is configured to block the diffused light beams (220) without the need of an additional shield placed at a distance from the light-entry lens surface (121) and to let direct light beams (210) entry the light-entry lens surface (121) through the transparent region (124).

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the field of vehicle lighting system, particularly relates to the light projection systems for vehicles.BACKGROUND OF THE INVENTION

[0002] Various vehicle lighting systems are known in the prior art to produce an illuminating beam, a signaling beam, or a combination of both. In conventional designs, vehicle lighting systems are used to enhance visibility and safety by providing clear and bright illumination for drivers and pedestrians. These systems are critical in ensuring effective communication of vehicle intentions and improving overall road safety.

[0003] However, regulation on road illumination becomes more and more strict regarding areas that should be covered by the beams and areas that should remain in the dark so as to prevent any risk of glare of an opposite road user.

[0004] This antagonistic requirement can become all the more difficult to meet as the light intensity threshold is set to a high level in illuminated areas. Hence, precise and high-contrast projections of beams, free of artefacts and halo effects, are often appreciated as a valuable feature of the lighting system for its ability to meet high standard requirements.

[0005] Therefore, there is a need to reduce the artefacts and halo effects in the projections on the road, in order to improve the quality of the illumination, while meeting high standard requirements regarding illuminated and non-illuminated areas of the road.

[0006] The need becomes even more critical when the light system is used for displaying images, symbols, and creating shadowing effects on road surfaces or to open areas, such as using Matrix High Beam (MHB) technology.

[0007] Recent advancements in lighting technology have led to the development of high-resolution projection systems capable of displaying images, symbols or shadows on road surfaces or to open areas. For example, this capability is particularly beneficial for advanced driver assistance systems (ADAS), which rely on precise and high-contrast projections to convey important information to drivers.

[0008] However, the existing light projection systems, which use for example Light Emitting Diode (LED) as light sources, including traditional LED and micro-LED (µLED), such as multi-row or / and multi-column LED or µLED arrays, face challenges in meeting the requirements of precise and high-contrast projections on road surfaces or to open areas, whether for illumination purposes or for displaying images, symbols, or creating shadowing effects. There are two main issues to address.

[0009] Firstly, the diffused light rays emitted from the light sources interact with the primary lens, resulting in the degradation of contrast and clarity of the projections, such as projected images, on the road. This interaction, caused by the diffused light, creates unwanted artefacts including halo effects in the projections on the road.

[0010] These artefacts are even more significant when the multi-row or / and multi-column LED or µLED arrays are used as light sources. In particular, the µLEDs are used because they offer several advantages, including superior brightness, color accuracy, and the ability to produce high-resolution images and shadowing effects. The µLEDs can be densely packed into a small area, making them ideal for applications requiring detailed and clear projections. However, due to their small size and high packing density, µLEDs generated more diffused or / and parasitic light compared to traditional LEDs. Therefore, the light projection system using µLEDs has a greater need to address artefacts including halo effects compared to traditional light projection system.

[0011] In addition, more than one lens is often used in a light projection system. This accentuates the artefacts and halo effects in the projections on the road.

[0012] Secondly, another issue is the susceptibility of the light sources, such as LED chips, to be damaged by sunlight. This sunlight is commonly referred to as "sunload". This is because the sun rays could go through the lens of the light projection system and reach, or even focus on, the light sources. Exposure to intense sunlight can not only affect the performance of the LEDs but also potentially damage the chips, reducing their lifespan and reliability.

[0013] To reduce the sunload on the light sources of the light projection system, existing designs have introduced additional components within the light projection system. These typically involve the use of additional parts, such as metal sheet or other materials, that serve as shields or shutters placed between the light sources and the primary lens. These shields are designed to partially block sun rays to reach the light sources.

[0014] However, the additional components, such as metal shields, are positioned at a distance from the lens, due to assembly constraints. Their non-negligible thickness introduces a first disadvantage, as it can cause unwanted artefacts in the projections. Secondly, their position relative to the lens often creates additional unwanted artefacts, such as lines or small spots, particularly on the edges of the symbols, images, or shadows of the MHB displayed on the road. These artefacts negatively impact the overall quality and contrast of the projection, exacerbating the artefacts issues caused by diffused light.

[0015] Therefore, there is a need to reduce the artefacts such as halo effects in the projections on the road, in order to improve the quality of the projected images, while minimizing the impact of sunload on light sources of the light projection systems.SUMMARY OF THE INVENTION

[0016] The present invention aims to overcome the shortcomings of the prior art by providing a light projection system for vehicles minimizing unwanted artefacts and halo effects caused by diffused light rays from its light sources, while reducing the impact of sunload on its light sources. The light projection system of the present invention is even more valuable in its embodiments which are used for displaying images, symbols and shadows on road surfaces or to open areas, while it can be used for various purposes including traditional illuminations.

[0017] To this end, the invention relates to a light projection system for a vehicle, comprising a light source unit, comprising a light emitting surface emitting light beams comprising direct light beams and diffused light beams, a primary lens comprising an optical axis, a light-entry lens surface facing the light source unit and a light-exit lens surface, wherein the light-entry lens surface comprises at least one non-transparent region and at least one transparent region, the non-transparent region being configured to block diffused light beams without the need of an additional shield placed at a distance from the light-entry lens surface and to let direct light beams entry the light-entry lens surface through the transparent region.

[0018] The term "transparent" refers to an optical environment where the light passes through optical elements with minimal losses and without scattering. The term "non-transparent" includes both "translucent" and "opaque". A translucent optical environment means that a portion of the light passes through the optical element, while the remaining light is scattered. This may apply to materials that are dim or have a structured, grainy, or milky appearance. An opaque optical environment means that all light is scattered, and no light passes through the optical element. In other words, an opaque material blocks all light, preventing any transmission or clear passage through it. For example, this may apply to surfaces painted black. The aforementioned term "light" includes at least any electromagnetic radiation with a wavelength comprised in the visible light spectrum, that is to say, from 380 nm to 780 nm. Preferably, "light" may also include non-visible light, i.e., infrared (IR) radiation (780 nm to 1 mm) and ultraviolet (UV) radiation (200 nm to 400 nm). Advantageously, "light" may also include any electromagnetic radiation with other wavelength comprised in the electromagnetic spectrum, such as X-rays, microwaves and radio waves.

[0019] First, the light-entry lens surface of the primary lens comprises non-transparent region, i.e., translucent or / and opaque region, being configured to block diffused light beams and to let direct light beams entry the light-entry lens surface through the transparent region, effectively blocking diffused light rays emitted by the light sources, significantly reducing artefacts and halo effects caused by the interaction between the diffused light rays and the primary lens. Secondly, the non-transparent regions of the light-entry lens surface is configured to block diffused light beams without the need of an additional shield placed at a distance from the light-entry lens surface. This configuration eliminates the gap that is typically created by an additional component, such as shield or cover, in the prior art. As a result, the additional artefacts caused by the gap between the additional component and the light-entry lens surface, by the thickness of the additional component, or by the reflection from the additional component are effectively eliminated.

[0020] Therefore, the present invention allows a significant reduction of the artefacts in the projection on road surfaces or open areas.

[0021] According to preferred embodiments, the light projection system for a vehicle according to the invention may further comprise the following features, implemented separately or in each of their technically operative combinations.

[0022] According to a preferred embodiment, the non-transparent region of the light-entry lens surface at least partially shields sun rays which enters into the light projection system through the light-exit lens surface, towards the light source unit. In some embodiments of the present invention, the sunload reaching the light emitting surface of the light source unit can be reduced by, for example, 50%, thereby preventing potential damage to the light source done by the sun rays. In other embodiments, the percentage of the sunload reduction may vary depending on the size of the non-transparent zones, the intensity of the sunload, and other relevant parameters.

[0023] Preferably, the non-transparent region is opaque to the light radiation which includes at least visible light and non-visible light such as infrared (IR) radiation and ultraviolet (UV) radiation. This enhances the reduction of sunload, primarily attributed to IR and UV radiation.

[0024] Advantageously, the light-entry lens surface has an integrated non-transparent layer in the non-transparent region.

[0025] According to a preferred embodiment, the integrated non-transparent layer of the non-transparent region of the light-entry lens surface is formed by surface treatment, with or without adding material to the light-entry lens surface, such as painting, graining, metallization, grain structure formation, laser burning or molding. As a non-exclusive example, the surface treatment to form the integrated non-transparent layer of the non-transparent region includes the following actions: adding material to the light-entry lens surface of the primary lens, removing material from the light-entry lens surface, or altering the material of the light-entry lens surface without adding or removing any substance. For example, painting results in adding a coating layer on the light-entry lens surface in the non-transparent region; graining may remove material from the light-entry lens surface in the non-transparent region; laser burning can result in a mark or discoloration of the material of the light-entry lens surface in the non-transparent region.

[0026] Advantageously, edges of the non-transparent layer of the non-transparent region of the light-entry lens surface are not perceptible. In other words, the light-entry lens surface has a seamless transition between the non-transparent and transparent regions. In other words, the thickness of the non-transparent layer is not perceptible. This feature avoids significant steps between different regions, thus eliminates additional artefacts on the edges of the projections caused by the thickness of the non-transparent layer, for example, the lines or small spots on the edges of symbols, images or shadows displayed on the road or to the open area. In practice, the aforementioned surface treatments can be accurately controlled, for example, the added layer or removed layer can be as thin as possible, in order to ensure a continuity of the light-entry lens surface between the transparent and non-transparent regions.

[0027] Advantageously, the transparent region is positioned in the center of the light-entry lens surface. This arrangement allows an optimal performance in terms of the quality of the final projections on road surfaces or to open areas.

[0028] According to a preferred embodiment, once the light projection system is installed on the vehicle, the non-transparent region is positioned on top and / or bottom of the light-entry lens surface when the vehicle is oriented in its usual upright position. Preferably, the non-transparent region on top and / or bottom extends the full width of the light-entry lens surface when the vehicle is oriented in its usual upright position.

[0029] According to another preferred embodiment, once the light projection system is installed on the vehicle, the non-transparent region is positioned on at least one of vertical sides of the light-entry lens surface when the vehicle is oriented in its usual upright position. Preferably, the non-transparent region on at least one vertical sides of the light-entry lens surface extends the full height of the light-entry lens surface when the vehicle is oriented in its usual upright position.

[0030] Preferably, the transparent region of the light-entry lens surface has a dimension equal to a dimension of the light emitting surface of the light source unit. This arrangement maximizes the blocking of diffused light while maintaining high light efficiency.

[0031] Preferably, the light projection system comprises at least two lenses including the primary lens. The at least two lenses are arranged along a direction of the optical axis of the primary lens. Multiples lens can further refine projected images through magnification correction, distortion reduction, or chromatic aberration compensation.

[0032] Advantageously, the light projection system comprises a lens holder extending along the direction of the optical axis of the primary lens. The primary lens or the at least two lenses are fixed to the lens holder. The lens holder supports the lenses.

[0033] According to a preferred embodiment, the light source unit of the light projection system comprises at least one light-emitting diode (LED).

[0034] Preferably, the light source unit comprises at least one micro light-emitting diode (µLEDs). For example, the light source unit comprises an array of multiple micro light-emitting diodes (µLEDs).

[0035] Advantageously, the light source unit comprises an array of multiple-row and / or multiple-column micro light-emitting diodes (µLEDs). An array of µLEDs offer superior brightness, color accuracy, and high-resolution capabilities in final projections, particularly when projecting images, symbols or shadows on road surfaces or to open areas. However, as mentioned above, the artefacts and halo effects are more pronounced when using the µLEDs as light sources in the light projection system. In addition, the system becomes more sensitive to gaps between its components, such as an additional cover and the light-entry lens surfaces of the primary lens in the prior art. Therefore, the combination of the light-entry lens surface with integrated non-transparent regions and the use of µLEDs as light source, results in high-contrast, high-quality projections of images, symbols and shadows on road surfaces or to open areas.

[0036] The invention also relates to a vehicle comprising at least one light projection system as described above.BRIEF DESCRIPTION OF THE FIGURES

[0037] The invention will be better understood upon reading the following description, provided only as an illustrative example. The terms "top", "bottom", "front" and "rear" refer to the directions once the light projection system is installed on a vehicle oriented in its usual upright position. The following description is with reference to the attached drawings in which: Figure 1 is a side view of the light projection system according to a particular embodiment of the invention, Figures 2A to 2C are front views of the light-entry lens surface of the primary lens of the light projection system according to different embodiments of the invention, Figure 3 is a side view of the light projection system according to a particular embodiment of the invention, showing the light beams emitting by the light source unit, Figure 4 is a side view of the light projection system of Figure 3, showing the light rays emitting by the sun. DETAILED DESCRIPTION

[0038] Figure 1 illustrates a light projection system 100 for a vehicle (not shown) comprising a light source unit 110 and a primary lens 120. The light source unit 110 has a light emitting surface which emits light beams 200.

[0039] The light beams 200 includes direct light beams 210 and diffused light beams 220. The direct light beams 210 are parallel and travel along a direction of an optical axis D of the primary lens 120, towards a light-entry lens surface 121 of the primary lens 120, and exist through a light-exit lens surface 122 of the primary lens 120. The diffused light beams 220 diverge in various directions.

[0040] In the present embodiment as illustrated in Figure 1, the light-entry lens surface 121 of the primary lens 120 comprises two non-transparent regions 123. The non-transparent regions 123 are non-transparent to light. Preferably, the non-transparent regions 123 are opaque. The remaining regions of the light-entry lens surface constitute a transparent region 124, which is transparent to light. As illustrated in Figure 1, the non-transparent regions 123 block diffused light beams 220 that diverge toward them, while direct light beams 210 go through the transparent region 124 of the light-entry lens surface 121.

[0041] Preferably, the transparent region 124 of the light-entry lens surface 121 has a dimension approximately equal to a dimension of the light emitting surface of the light source unit 110.

[0042] In the present embodiment as illustrated in Figure 1, the two non-transparent regions 123 are positioned on top and bottom of the light-entry lens surface 121, extending the full width of the light-entry lens surface 121, as illustrated in Figure 2A. According to other embodiments of the invention, the non-transparent regions 123 can be positioned on one or both vertical sides of the light-entry lens surface 121, extending the full height of the light-entry lens surface 121, as illustrated in Figure 2B, or a combination thereof, i.e., on all edges of the light-entry lens surface 121, as illustrated in Figure 2C.

[0043] Preferably, the transparent region 124 is positioned in the center of the light-entry lens surface 121, as illustrated in Figures 2A to 2C.

[0044] Advantageously, the primary lens 120 can be made of plastic or of glass. The choice of the materials of the primary lens 120 depends on specific design requirements. For example, lightweight polymers like polycarbonate can be used for the primary lens, and economical ABS plastic or acrylic can be used for cost-effective applications where high-performance optics are not critical. In some embodiments, the lens can have coatings, for example, anti-reflective (AR) coating and / or Infrared (IR) coating.

[0045] Preferably, the non-transparent regions 123 of the light-entry lens surface 121 are obtained by surface treatment technologies, for example, painting, graining, metallization, grain structure formation, laser burning or molding directly on the lens. These surface treatments can be done on the plastic or glass lenses. Advantageously, the surface treatments are realized in a way that the non-transparent regions 123 and the transparent region 124 are contiguous and form a smooth transition without a perceptible step or discontinuity between them.

[0046] In another embodiment as illustrated in Figure 3, the light projection system 100 for a vehicle comprises the light source unit 110 and the primary lens 120 as described in the embodiment illustrated in Figure 1. In addition, the light projection system 100 comprises two additional lenses, including a secondary lens 140 and a third lens 160. The three lenses 120, 140, 160 are arranged along the direction of the optical axis D of the primary lens 120.

[0047] Preferably, the light projection system 100 comprises a lens holder 130. The lens holder 130 extends along the direction of the optical axis D of the primary lens 120. The lenses 120, 140, 160 are fixed to the lens holder 130.

[0048] Advantageously, the lens holder 130 comprises side walls which serves to block stray light. The lens holder 130 can be made of metal or plastic material. Preferably, the lens holder 130 is made of a light-absorbing material, such as black polycarbonate (PC).

[0049] In a preferred embodiment of the invention, the light source unit 110 of the light projection system 100 comprises at least one light-emitting diode (LED) (not shown in the figures). Preferably, the light source unit 110 comprises an array of multiple LEDs.

[0050] Advantageously, the light source unit 110 comprises at least one micro light-emitting diode (µLED) (not shown in the figures). Preferably, the light source unit 110 comprises an array of multiple µLEDs.

[0051] As a non-limiting example, 2500 µLEDs can be arranged in the light source unit, forming a small square as an emitting surface of the light source unit. Each µLED can be switched on and off separately, in order to project desired images, symbols or shadows with a high resolution.

[0052] Figure 4 illustrates the non-transparent regions 123 of the light-entry lens surface 121 of the primary lens 120 shield partially sun rays 300 of the sun. The light source unit 110, particularly comprising LEDs, is therefore protected from damage by the sunload.

[0053] The invention is not limited to the presented embodiments and other embodiments will clearly appear to the skilled person. Any combination of the aforementioned embodiments or variants is for example explicitly envisioned.Reference list

[0054] 100: light projection system 110: light source unit 120: primary lens 121: light-entry lens surface 122: light-exit lens surface 123: non-transparent region 124: transparent region 130: lens holder 140, 160: lens 200: light beams 210: direct light beams 220: diffused light beams 300: sun rays

Examples

Embodiment Construction

[0038]Figure 1 illustrates a light projection system 100 for a vehicle (not shown) comprising a light source unit 110 and a primary lens 120. The light source unit 110 has a light emitting surface which emits light beams 200.

[0039]The light beams 200 includes direct light beams 210 and diffused light beams 220. The direct light beams 210 are parallel and travel along a direction of an optical axis D of the primary lens 120, towards a light-entry lens surface 121 of the primary lens 120, and exist through a light-exit lens surface 122 of the primary lens 120. The diffused light beams 220 diverge in various directions.

[0040]In the present embodiment as illustrated in Figure 1, the light-entry lens surface 121 of the primary lens 120 comprises two non-transparent regions 123. The non-transparent regions 123 are non-transparent to light. Preferably, the non-transparent regions 123 are opaque. The remaining regions of the light-entry lens surface constitute a transparent region 124, whic...

FIELD OF THE INVENTION

[0001] The present invention relates to the field of vehicle lighting system, particularly relates to the light projection systems for vehicles.BACKGROUND OF THE INVENTION

[0002] Various vehicle lighting systems are known in the prior art to produce an illuminating beam, a signaling beam, or a combination of both. In conventional designs, vehicle lighting systems are used to enhance visibility and safety by providing clear and bright illumination for drivers and pedestrians. These systems are critical in ensuring effective communication of vehicle intentions and improving overall road safety.

[0003] However, regulation on road illumination becomes more and more strict regarding areas that should be covered by the beams and areas that should remain in the dark so as to prevent any risk of glare of an opposite road user.

[0004] This antagonistic requirement can become all the more difficult to meet as the light intensity threshold is set to a high level in illuminated areas. Hence, precise and high-contrast projections of beams, free of artefacts and halo effects, are often appreciated as a valuable feature of the lighting system for its ability to meet high standard requirements.

[0005] Therefore, there is a need to reduce the artefacts and halo effects in the projections on the road, in order to improve the quality of the illumination, while meeting high standard requirements regarding illuminated and non-illuminated areas of the road.

[0006] The need becomes even more critical when the light system is used for displaying images, symbols, and creating shadowing effects on road surfaces or to open areas, such as using Matrix High Beam (MHB) technology.

[0007] Recent advancements in lighting technology have led to the development of high-resolution projection systems capable of displaying images, symbols or shadows on road surfaces or to open areas. For example, this capability is particularly beneficial for advanced driver assistance systems (ADAS), which rely on precise and high-contrast projections to convey important information to drivers.

[0008] However, the existing light projection systems, which use for example Light Emitting Diode (LED) as light sources, including traditional LED and micro-LED (µLED), such as multi-row or / and multi-column LED or µLED arrays, face challenges in meeting the requirements of precise and high-contrast projections on road surfaces or to open areas, whether for illumination purposes or for displaying images, symbols, or creating shadowing effects. There are two main issues to address.

[0009] Firstly, the diffused light rays emitted from the light sources interact with the primary lens, resulting in the degradation of contrast and clarity of the projections, such as projected images, on the road. This interaction, caused by the diffused light, creates unwanted artefacts including halo effects in the projections on the road.

[0010] These artefacts are even more significant when the multi-row or / and multi-column LED or µLED arrays are used as light sources. In particular, the µLEDs are used because they offer several advantages, including superior brightness, color accuracy, and the ability to produce high-resolution images and shadowing effects. The µLEDs can be densely packed into a small area, making them ideal for applications requiring detailed and clear projections. However, due to their small size and high packing density, µLEDs generated more diffused or / and parasitic light compared to traditional LEDs. Therefore, the light projection system using µLEDs has a greater need to address artefacts including halo effects compared to traditional light projection system.

[0011] In addition, more than one lens is often used in a light projection system. This accentuates the artefacts and halo effects in the projections on the road.

[0012] Secondly, another issue is the susceptibility of the light sources, such as LED chips, to be damaged by sunlight. This sunlight is commonly referred to as "sunload". This is because the sun rays could go through the lens of the light projection system and reach, or even focus on, the light sources. Exposure to intense sunlight can not only affect the performance of the LEDs but also potentially damage the chips, reducing their lifespan and reliability.

[0013] To reduce the sunload on the light sources of the light projection system, existing designs have introduced additional components within the light projection system. These typically involve the use of additional parts, such as metal sheet or other materials, that serve as shields or shutters placed between the light sources and the primary lens. These shields are designed to partially block sun rays to reach the light sources.

[0014] However, the additional components, such as metal shields, are positioned at a distance from the lens, due to assembly constraints. Their non-negligible thickness introduces a first disadvantage, as it can cause unwanted artefacts in the projections. Secondly, their position relative to the lens often creates additional unwanted artefacts, such as lines or small spots, particularly on the edges of the symbols, images, or shadows of the MHB displayed on the road. These artefacts negatively impact the overall quality and contrast of the projection, exacerbating the artefacts issues caused by diffused light.

[0015] Therefore, there is a need to reduce the artefacts such as halo effects in the projections on the road, in order to improve the quality of the projected images, while minimizing the impact of sunload on light sources of the light projection systems.SUMMARY OF THE INVENTION

[0016] The present invention aims to overcome the shortcomings of the prior art by providing a light projection system for vehicles minimizing unwanted artefacts and halo effects caused by diffused light rays from its light sources, while reducing the impact of sunload on its light sources. The light projection system of the present invention is even more valuable in its embodiments which are used for displaying images, symbols and shadows on road surfaces or to open areas, while it can be used for various purposes including traditional illuminations.

[0017] To this end, the invention relates to a light projection system for a vehicle, comprising a light source unit, comprising a light emitting surface emitting light beams comprising direct light beams and diffused light beams, a primary lens comprising an optical axis, a light-entry lens surface facing the light source unit and a light-exit lens surface, wherein the light-entry lens surface comprises at least one non-transparent region and at least one transparent region, the non-transparent region being configured to block diffused light beams without the need of an additional shield placed at a distance from the light-entry lens surface and to let direct light beams entry the light-entry lens surface through the transparent region.

[0018] The term "transparent" refers to an optical environment where the light passes through optical elements with minimal losses and without scattering. The term "non-transparent" includes both "translucent" and "opaque". A translucent optical environment means that a portion of the light passes through the optical element, while the remaining light is scattered. This may apply to materials that are dim or have a structured, grainy, or milky appearance. An opaque optical environment means that all light is scattered, and no light passes through the optical element. In other words, an opaque material blocks all light, preventing any transmission or clear passage through it. For example, this may apply to surfaces painted black. The aforementioned term "light" includes at least any electromagnetic radiation with a wavelength comprised in the visible light spectrum, that is to say, from 380 nm to 780 nm. Preferably, "light" may also include non-visible light, i.e., infrared (IR) radiation (780 nm to 1 mm) and ultraviolet (UV) radiation (200 nm to 400 nm). Advantageously, "light" may also include any electromagnetic radiation with other wavelength comprised in the electromagnetic spectrum, such as X-rays, microwaves and radio waves.

[0019] First, the light-entry lens surface of the primary lens comprises non-transparent region, i.e., translucent or / and opaque region, being configured to block diffused light beams and to let direct light beams entry the light-entry lens surface through the transparent region, effectively blocking diffused light rays emitted by the light sources, significantly reducing artefacts and halo effects caused by the interaction between the diffused light rays and the primary lens. Secondly, the non-transparent regions of the light-entry lens surface is configured to block diffused light beams without the need of an additional shield placed at a distance from the light-entry lens surface. This configuration eliminates the gap that is typically created by an additional component, such as shield or cover, in the prior art. As a result, the additional artefacts caused by the gap between the additional component and the light-entry lens surface, by the thickness of the additional component, or by the reflection from the additional component are effectively eliminated.

[0020] Therefore, the present invention allows a significant reduction of the artefacts in the projection on road surfaces or open areas.

[0021] According to preferred embodiments, the light projection system for a vehicle according to the invention may further comprise the following features, implemented separately or in each of their technically operative combinations.

[0022] According to a preferred embodiment, the non-transparent region of the light-entry lens surface at least partially shields sun rays which enters into the light projection system through the light-exit lens surface, towards the light source unit. In some embodiments of the present invention, the sunload reaching the light emitting surface of the light source unit can be reduced by, for example, 50%, thereby preventing potential damage to the light source done by the sun rays. In other embodiments, the percentage of the sunload reduction may vary depending on the size of the non-transparent zones, the intensity of the sunload, and other relevant parameters.

[0023] Preferably, the non-transparent region is opaque to the light radiation which includes at least visible light and non-visible light such as infrared (IR) radiation and ultraviolet (UV) radiation. This enhances the reduction of sunload, primarily attributed to IR and UV radiation.

[0024] Advantageously, the light-entry lens surface has an integrated non-transparent layer in the non-transparent region.

[0025] According to a preferred embodiment, the integrated non-transparent layer of the non-transparent region of the light-entry lens surface is formed by surface treatment, with or without adding material to the light-entry lens surface, such as painting, graining, metallization, grain structure formation, laser burning or molding. As a non-exclusive example, the surface treatment to form the integrated non-transparent layer of the non-transparent region includes the following actions: adding material to the light-entry lens surface of the primary lens, removing material from the light-entry lens surface, or altering the material of the light-entry lens surface without adding or removing any substance. For example, painting results in adding a coating layer on the light-entry lens surface in the non-transparent region; graining may remove material from the light-entry lens surface in the non-transparent region; laser burning can result in a mark or discoloration of the material of the light-entry lens surface in the non-transparent region.

[0026] Advantageously, edges of the non-transparent layer of the non-transparent region of the light-entry lens surface are not perceptible. In other words, the light-entry lens surface has a seamless transition between the non-transparent and transparent regions. In other words, the thickness of the non-transparent layer is not perceptible. This feature avoids significant steps between different regions, thus eliminates additional artefacts on the edges of the projections caused by the thickness of the non-transparent layer, for example, the lines or small spots on the edges of symbols, images or shadows displayed on the road or to the open area. In practice, the aforementioned surface treatments can be accurately controlled, for example, the added layer or removed layer can be as thin as possible, in order to ensure a continuity of the light-entry lens surface between the transparent and non-transparent regions.

[0027] Advantageously, the transparent region is positioned in the center of the light-entry lens surface. This arrangement allows an optimal performance in terms of the quality of the final projections on road surfaces or to open areas.

[0028] According to a preferred embodiment, once the light projection system is installed on the vehicle, the non-transparent region is positioned on top and / or bottom of the light-entry lens surface when the vehicle is oriented in its usual upright position. Preferably, the non-transparent region on top and / or bottom extends the full width of the light-entry lens surface when the vehicle is oriented in its usual upright position.

[0029] According to another preferred embodiment, once the light projection system is installed on the vehicle, the non-transparent region is positioned on at least one of vertical sides of the light-entry lens surface when the vehicle is oriented in its usual upright position. Preferably, the non-transparent region on at least one vertical sides of the light-entry lens surface extends the full height of the light-entry lens surface when the vehicle is oriented in its usual upright position.

[0030] Preferably, the transparent region of the light-entry lens surface has a dimension equal to a dimension of the light emitting surface of the light source unit. This arrangement maximizes the blocking of diffused light while maintaining high light efficiency.

[0031] Preferably, the light projection system comprises at least two lenses including the primary lens. The at least two lenses are arranged along a direction of the optical axis of the primary lens. Multiples lens can further refine projected images through magnification correction, distortion reduction, or chromatic aberration compensation.

[0032] Advantageously, the light projection system comprises a lens holder extending along the direction of the optical axis of the primary lens. The primary lens or the at least two lenses are fixed to the lens holder. The lens holder supports the lenses.

[0033] According to a preferred embodiment, the light source unit of the light projection system comprises at least one light-emitting diode (LED).

[0034] Preferably, the light source unit comprises at least one micro light-emitting diode (µLEDs). For example, the light source unit comprises an array of multiple micro light-emitting diodes (µLEDs).

[0035] Advantageously, the light source unit comprises an array of multiple-row and / or multiple-column micro light-emitting diodes (µLEDs). An array of µLEDs offer superior brightness, color accuracy, and high-resolution capabilities in final projections, particularly when projecting images, symbols or shadows on road surfaces or to open areas. However, as mentioned above, the artefacts and halo effects are more pronounced when using the µLEDs as light sources in the light projection system. In addition, the system becomes more sensitive to gaps between its components, such as an additional cover and the light-entry lens surfaces of the primary lens in the prior art. Therefore, the combination of the light-entry lens surface with integrated non-transparent regions and the use of µLEDs as light source, results in high-contrast, high-quality projections of images, symbols and shadows on road surfaces or to open areas.

[0036] The invention also relates to a vehicle comprising at least one light projection system as described above.BRIEF DESCRIPTION OF THE FIGURES

[0037] The invention will be better understood upon reading the following description, provided only as an illustrative example. The terms "top", "bottom", "front" and "rear" refer to the directions once the light projection system is installed on a vehicle oriented in its usual upright position. The following description is with reference to the attached drawings in which: Figure 1 is a side view of the light projection system according to a particular embodiment of the invention, Figures 2A to 2C are front views of the light-entry lens surface of the primary lens of the light projection system according to different embodiments of the invention, Figure 3 is a side view of the light projection system according to a particular embodiment of the invention, showing the light beams emitting by the light source unit, Figure 4 is a side view of the light projection system of Figure 3, showing the light rays emitting by the sun. DETAILED DESCRIPTION

[0038] Figure 1 illustrates a light projection system 100 for a vehicle (not shown) comprising a light source unit 110 and a primary lens 120. The light source unit 110 has a light emitting surface which emits light beams 200.

[0039] The light beams 200 includes direct light beams 210 and diffused light beams 220. The direct light beams 210 are parallel and travel along a direction of an optical axis D of the primary lens 120, towards a light-entry lens surface 121 of the primary lens 120, and exist through a light-exit lens surface 122 of the primary lens 120. The diffused light beams 220 diverge in various directions.

[0040] In the present embodiment as illustrated in Figure 1, the light-entry lens surface 121 of the primary lens 120 comprises two non-transparent regions 123. The non-transparent regions 123 are non-transparent to light. Preferably, the non-transparent regions 123 are opaque. The remaining regions of the light-entry lens surface constitute a transparent region 124, which is transparent to light. As illustrated in Figure 1, the non-transparent regions 123 block diffused light beams 220 that diverge toward them, while direct light beams 210 go through the transparent region 124 of the light-entry lens surface 121.

[0041] Preferably, the transparent region 124 of the light-entry lens surface 121 has a dimension approximately equal to a dimension of the light emitting surface of the light source unit 110.

[0042] In the present embodiment as illustrated in Figure 1, the two non-transparent regions 123 are positioned on top and bottom of the light-entry lens surface 121, extending the full width of the light-entry lens surface 121, as illustrated in Figure 2A. According to other embodiments of the invention, the non-transparent regions 123 can be positioned on one or both vertical sides of the light-entry lens surface 121, extending the full height of the light-entry lens surface 121, as illustrated in Figure 2B, or a combination thereof, i.e., on all edges of the light-entry lens surface 121, as illustrated in Figure 2C.

[0043] Preferably, the transparent region 124 is positioned in the center of the light-entry lens surface 121, as illustrated in Figures 2A to 2C.

[0044] Advantageously, the primary lens 120 can be made of plastic or of glass. The choice of the materials of the primary lens 120 depends on specific design requirements. For example, lightweight polymers like polycarbonate can be used for the primary lens, and economical ABS plastic or acrylic can be used for cost-effective applications where high-performance optics are not critical. In some embodiments, the lens can have coatings, for example, anti-reflective (AR) coating and / or Infrared (IR) coating.

[0045] Preferably, the non-transparent regions 123 of the light-entry lens surface 121 are obtained by surface treatment technologies, for example, painting, graining, metallization, grain structure formation, laser burning or molding directly on the lens. These surface treatments can be done on the plastic or glass lenses. Advantageously, the surface treatments are realized in a way that the non-transparent regions 123 and the transparent region 124 are contiguous and form a smooth transition without a perceptible step or discontinuity between them.

[0046] In another embodiment as illustrated in Figure 3, the light projection system 100 for a vehicle comprises the light source unit 110 and the primary lens 120 as described in the embodiment illustrated in Figure 1. In addition, the light projection system 100 comprises two additional lenses, including a secondary lens 140 and a third lens 160. The three lenses 120, 140, 160 are arranged along the direction of the optical axis D of the primary lens 120.

[0047] Preferably, the light projection system 100 comprises a lens holder 130. The lens holder 130 extends along the direction of the optical axis D of the primary lens 120. The lenses 120, 140, 160 are fixed to the lens holder 130.

[0048] Advantageously, the lens holder 130 comprises side walls which serves to block stray light. The lens holder 130 can be made of metal or plastic material. Preferably, the lens holder 130 is made of a light-absorbing material, such as black polycarbonate (PC).

[0049] In a preferred embodiment of the invention, the light source unit 110 of the light projection system 100 comprises at least one light-emitting diode (LED) (not shown in the figures). Preferably, the light source unit 110 comprises an array of multiple LEDs.

[0050] Advantageously, the light source unit 110 comprises at least one micro light-emitting diode (µLED) (not shown in the figures). Preferably, the light source unit 110 comprises an array of multiple µLEDs.

[0051] As a non-limiting example, 2500 µLEDs can be arranged in the light source unit, forming a small square as an emitting surface of the light source unit. Each µLED can be switched on and off separately, in order to project desired images, symbols or shadows with a high resolution.

[0052] Figure 4 illustrates the non-transparent regions 123 of the light-entry lens surface 121 of the primary lens 120 shield partially sun rays 300 of the sun. The light source unit 110, particularly comprising LEDs, is therefore protected from damage by the sunload.

[0053] The invention is not limited to the presented embodiments and other embodiments will clearly appear to the skilled person. Any combination of the aforementioned embodiments or variants is for example explicitly envisioned.Reference list

[0054] 100: light projection system 110: light source unit 120: primary lens 121: light-entry lens surface 122: light-exit lens surface 123: non-transparent region 124: transparent region 130: lens holder 140, 160: lens 200: light beams 210: direct light beams 220: diffused light beams 300: sun rays

Examples

Embodiment Construction

[0038]Figure 1 illustrates a light projection system 100 for a vehicle (not shown) comprising a light source unit 110 and a primary lens 120. The light source unit 110 has a light emitting surface which emits light beams 200.

[0039]The light beams 200 includes direct light beams 210 and diffused light beams 220. The direct light beams 210 are parallel and travel along a direction of an optical axis D of the primary lens 120, towards a light-entry lens surface 121 of the primary lens 120, and exist through a light-exit lens surface 122 of the primary lens 120. The diffused light beams 220 diverge in various directions.

[0040]In the present embodiment as illustrated in Figure 1, the light-entry lens surface 121 of the primary lens 120 comprises two non-transparent regions 123. The non-transparent regions 123 are non-transparent to light. Preferably, the non-transparent regions 123 are opaque. The remaining regions of the light-entry lens surface constitute a transparent region 124, whic...

Claims

1. A light projection system (100) for a vehicle, comprising - a light source unit (110), comprising a light emitting surface emitting light beams (200) comprising direct light beams (210) and diffused light beams (220), - a primary lens (120) comprising an optical axis (D), a light-entry lens surface (121) facing the light source unit (110) and a light-exit lens surface (122), characterized in that the light-entry lens surface (121) comprises at least one non-transparent region (123) and at least one transparent region (124), the non-transparent region (123) being configured to block the diffused light beams (220) without the need of an additional shield placed at a distance from the light-entry lens surface (121) and to let direct light beams (210) entry the light-entry lens surface (121) through the transparent region (124).

2. The light projection system (100) for a vehicle according to claim 1, wherein the non-transparent region (123) of the light-entry lens surface (121) at least partially shields sun rays (300) which enters into the light projection system (100) through the light-exit lens surface (122), towards the light source unit (110).

3. The light projection system (100) for a vehicle according to claim 1 or 2, wherein the light-entry lens surface (121) has an integrated non-transparent layer in the non-transparent region (123).

4. The light projection system (100) for a vehicle according to claim 3, wherein the integrated non-transparent layer of the non-transparent region (123) of the light-entry lens surface (121) is formed by surface treatment, with or without adding material to the light-entry lens surface (121), such as painting, graining, metallization, grain structure formation, laser burning or molding.

5. The light projection system (100) for a vehicle according to claim 3 or 4, wherein edges of the non-transparent layer of the non-transparent region (123) of the light-entry lens surface (121) are not perceptible.

6. The light projection system (100) for a vehicle according to any one of the preceding claims, wherein the transparent region (124) is positioned in the center of the light-entry lens surface (121).

7. The light projection system (100) for a vehicle according to any one of the preceding claims, wherein once the light projection system (100) is installed on the vehicle, the non-transparent region (123) is positioned on top and / or bottom of the light-entry lens surface (121) when the vehicle is oriented in its usual upright position.

8. The light projection system (100) for a vehicle according to claim 7, wherein the non-transparent region (123) on top and / or bottom extends the full width of the light-entry lens surface (121) when the vehicle is oriented in its usual upright position.

9. The light projection system (100) for a vehicle according to any one of the preceding claims, wherein once the light projection system (100) is installed on the vehicle, the non-transparent region (123) is positioned on at least one of vertical sides of the light-entry lens surface (121) when the vehicle is oriented in its usual upright position.

10. The light projection system (100) for a vehicle according to any one of the preceding claims, comprising at least two lenses (120, 140, 160), including the primary lens (120), wherein the at least two lenses (120, 140, 160) are arranged along a direction of the optical axis (D) of the primary lens (120).

11. The light projection system (100) for a vehicle according to any one of the preceding claims, comprising a lens holder (130) extending along the direction of the optical axis (D) of the primary lens (120), with the primary lens (120) or the at least two lenses (120, 140, 160) being fixed to the lens holder (130).

12. The light projection system (100) for a vehicle according to any one of the preceding claims, wherein the light source unit (110) comprises at least one light-emitting diode.

13. The light projection system (100) for a vehicle according to any one of the preceding claims, wherein the light source unit (110) comprises at least one micro light-emitting diode.

14. The light projection system (100) for a vehicle according to claim 13, wherein the light source unit (110) comprises an array of multiple-row and / or multi-column micro light-emitting diodes.

15. A vehicle, characterized in that it comprises at least one light projection system (100) according to any one of claims 1 to 14.

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