Optical device

Abstract

The present invention relates to an optical device for projecting a light beam, the device being capable of interacting with a pixelated light source (4) comprising a plurality of selectively activatable emitting elements, characterized in that the optical device comprises, in sequence along the path of the light beam, a first optical unit, a pupil, and a second optical unit, the first optical unit comprising an output refractive interface located at a first distance (d1) from the pupil, the second optical unit comprising an input refractive interface located at a second distance (d2) from the pupil, the second distance (d2) being substantially the same as the first distance (d1), and the first unit comprising a converging lens, and the second unit comprising a double lens, one of the double lenses being made of flint glass and the other of the double lens being made of crown glass.

Description

Technical Field

[0001] This invention relates to the field of lighting and / or signaling, and particularly to units that contribute to lighting and / or signaling, especially optical units. It is particularly advantageous for application in the field of motor vehicles.

[0002] It can be used to display pictograms on the surface on which the emitted light is projected, performing the function of writing roads. Simultaneously, this beam can be particularly used to form a far beam, preferably associated with a supplementary beam.

[0003] For example, the beam generated by the present invention can form part of a whole far beam while having a sufficiently high resolution to allow the function of writing on its path to be performed, and is accomplished by another beam, which, for example, has a wider but potentially lower resolution lateral projection field. Background Technology

[0004] In the automotive industry, devices that generally conform to regulations and are capable of emitting beams of light (also known as lighting and / or signaling functions) are known.

[0005] Techniques have recently been developed that allow the generation of segmented beams (also known as pixelated beams) to perform advanced lighting functions. For example, the present invention can allow the generation of pixelated beams, preferably with high resolution, particularly for signaling and / or facilitating functions that aid in illuminating the front of a vehicle.

[0006] A beam formed by different beam segments generated by each of the diodes is projected through a projection optics device that generally includes one or more lenses. For example, a supplementary high beam can be generated, which is associated with the basic beam projected entirely or at least primarily below the horizontal cutoff line in types used for low beam functions. The supplementary high beam is added to the basic beam to complete it above the cutoff line; advantageously, this high beam is adaptive, i.e., certain portions of the overall projected beam can be turned on or off, for example, for anti-glare functions. The acronym ADB (Adaptive Drive Beam) is used for this type of function.

[0007] In this specification, a beam whose projection forms an image composed of beam segments (each segment can be independently activated) is referred to as a segmented beam. These segments can be formed using a pixelated light source. Such a source comprises multiple selectively activated emitting elements. The emitting elements are typically placed side-by-side on a carrier at a certain spacing.

[0008] Ideally, the size of the source is unrestricted, and therefore a wider field of view can be covered to avoid limiting the application. Additionally, also theoretically, the resolution of the light source (i.e., the number of pixels) is unlimited, allowing for extremely fine sharpness.

[0009] In practice, the limitations of complexity and cost necessitate finding trade-offs, and therefore resolution is indeed limited.

[0010] One subject of the present invention is to provide a method for solving this problem, allowing satisfactory resolution, particularly for ADB beams, to be permitted.

[0011] Other objects, features, and advantages of the present invention will become apparent upon review of the following description and drawings. It should be understood that other advantages can be combined. Summary of the Invention

[0012] To achieve this objective, according to one embodiment, an optical device for projecting a light beam is specified, the optical device being capable of interacting with a pixelated light source comprising a plurality of selectively activatable emitting elements, characterized in that the optical device sequentially comprises, along the direction of light travel: a first optical unit, a pupil, and a second optical unit, the first optical unit comprising an exit refractive interface located at a first distance (d1) from the pupil, and the second optical unit comprising an incident refractive interface located at a second distance (d2) from the pupil, the second distance (d2) being substantially the same as the first distance (d1), and the first unit comprising a converging lens, and the second unit comprising a double lens, one of the lenses in the double lens being made of flint glass, and the other lens in the double lens being made of crown glass. Advantageously, the lens of the double lens made of flint glass is divergent, while the lens of the double lens made of crown glass is convergent.

[0013] Therefore, it is particularly useful for generating segmented beams with a resolution that may be higher than currently encountered in beams that facilitate long beams. Thus, with this invention, on-the-road writing applications that are not typically conceived in the case of ADB beams are realized.

[0014] While achieving improved resolution, deviations are suppressed through the symmetry of the optical elements located on both sides of the pupil and through the use of a double lens made of alternating flint and crown glass lenses in the second unit forming the exiting unit. This alternation particularly allows for the suppression of chromatic aberration, which is often limiting (and can even lead to product non-compliance) due to the numerical aperture required for distant beams. Furthermore, in the same manner that the Abbe numbers of the flint and crown glass are preferably selected to compensate for chromatic aberration in the resulting beam, the coefficients of thermal expansion of the flint and crown glass are preferably selected such that the thermal expansion of each lens compensates for the thermal expansion of the other lens, thus allowing for optimal performance retention over the widest possible temperature range.

[0015] In this context, one advantage of the present invention is the ability to selectively activate individual segments of the beam to achieve improved ADB high beam functionality, while allowing the ground to be written on, which typically requires a resolution higher than that of the ADB beam. Thus, these two functions are cleverly linked through the same projection module.

[0016] Optionally, the first optical unit includes a first converging lens forming the incident refractive interface of the first optical unit, and a second converging lens immediately following the first lens.

[0017] With these arrangements, the first converging lens can be used as a field aperture lens to define the angular amplitude of the projected beam. This lens can also be used as an aperture lens: it can be placed close to the light source (particularly between 3-6 mm from the light source, and preferably 5 mm); and its meniscus shape (preferably with a high radius of curvature) allows for the collection of light rays emitted from the light source at very large angles.

[0018] Advantageously, the optical device includes alternating flint and crown lenses to form a balanced optical assembly that limits color deviation; preferably, the first optical unit includes a double lens and the second optical unit includes another double lens, the two double lenses being symmetrical to have limited coma. The use of alternating flint and crown lenses also has the advantage of allowing performance to be optimized over a wider temperature range, in addition to color deviation correction, through compensation for thermal expansion.

[0019] On the other hand, a light emitting module is involved, which includes a device and a pixelated light source equipped with a plurality of selectively activatable emitting elements and configured to emit segmented beams.

[0020] On the other hand, it relates to motor vehicles equipped with at least one device and / or at least one module. Attached Figure Description

[0021] The objectives, features, and advantages of the present invention will become apparent from the following detailed description of an embodiment, illustrated in the accompanying drawings, wherein:

[0022] Figure 1 An example of the projection of the light beam generated by the present invention in front of a motor vehicle is shown.

[0023] Figure 2A and Figure 2B A first embodiment of the optical device is shown.

[0024] Figure 3A and Figure 3B A second embodiment of the optical device is shown.

[0025] Figure 4A and Figure 4B A third embodiment of the optical device is shown.

[0026] The accompanying drawings are given by way of example and do not limit the invention. They are illustrative and conceptual descriptions intended to facilitate understanding of the invention and do not necessarily have to be drawn to the scale of a practical application. Specific Implementation

[0027] Before beginning a detailed review of the embodiments of the present invention, optional features that may be used in combination or alternatively will now be described:

[0028] - The first optical unit includes a first converging lens forming an incident refractive interface of the first optical unit, and a second converging lens immediately following the first lens;

[0029] -The incident refractive interface has a crescent shape;

[0030] - The first optical unit includes a diverging lens that follows the second lens;

[0031] - The second lens and the diverging lens form a double lens, one of the lenses of the double lens being made of crown glass and the other lens of the double lens being made of flint glass;

[0032] - The lenses of the first unit and the second unit are alternating flint glass lenses and crown glass lenses along the direction of light travel.

[0033] - The second lens includes an incident refractive interface located at a third distance (d3) from the pupil, and the double lens of the second optical unit includes an exit refractive interface located at a fourth distance (d4) from the pupil, the third distance (d3) and the fourth distance (d4) being substantially the same;

[0034] - The double lenses of the first optical unit and the double lenses of the second optical unit have the same light intensity, which covers the case where they are very close (i.e., the difference is no more than 10%).

[0035] - The first optical unit and / or the second optical unit include at least one flint glass lens having a refractive index of at least 1.6, preferably at least 1.7, and preferably at least 1.8;

[0036] - The first optical unit and / or the second optical unit include at least one crown glass lens having a refractive index of at least 1.45, preferably at least 1.5, and more preferably at least 1.65;

[0037] - The device has a numerical aperture of less than 1, preferably less than 0.9, and more preferably less than or equal to 0.75;

[0038] - Flint glass lenses have an Abbe number <50, and preferably <45, and / or crown glass lenses have an Abbe number greater than 45, and preferably greater than 50;

[0039] - The beam performs the function of writing on the ground;

[0040] - The beam forms at least a portion of the entire far beam;

[0041] -Optionally, the transmitting elements are the same size;

[0042] - A computer program product, preferably stored in non-volatile memory, includes instructions that, when executed by a processor, can determine an emission element to be activated, particularly to obtain at least one dark area (where the element is not activated) of a determined area or pattern to be projected.

[0043] In the features described below, terms relating to verticality, horizontality, and laterality (or even lateral direction) or their equivalents should be understood as relative to the position in which the lighting system will be mounted in the vehicle. In this specification, the terms “vertical” and “horizontal” are used to specify: with respect to the term “vertical,” a direction oriented perpendicular to a horizontal plane (which corresponds to the height of the module), and with respect to the term “horizontal,” a direction oriented parallel to a horizontal plane. These are considered under the conditions of operation of the equipment in the vehicle. The use of these terms does not imply that minor variations relating to the vertical and horizontal directions are excluded from the invention. For example, an angle of inclination on the order of + or -10° relative to these directions is considered herein as a minor variation relating to the two preferred directions. Relative to a horizontal plane, the angle of inclination is in principle between -5° and +4°, and the lateral angle is between -6° and +7.5°.

[0044] Motor vehicle headlights may be equipped with one or more light-emitting modules arranged within a housing enclosed by an outer lens to obtain one or more illumination and / or signaling beams as output from the headlight. Simply put, the light-emitting module within the housing specifically includes a light source for emitting the beam, an optical device comprising one or more lenses, and, in some cases, optical elements (e.g., reflectors) for directing the light generated by the light source to form the beam output from the optical module. The same applies to taillights.

[0045] This invention can aid in high beam functionality, which aims to illuminate a large area of ​​the scene in front of the vehicle, and also assists at a considerable distance, typically around 200 meters. This beam, due to its illumination function, is primarily positioned above the horizon. For example, it can have a slightly upward-sloping illumination optical axis. In particular, it can be used to generate a "supplementary high beam" illumination function, which forms a segment of the high beam that supplements the segment produced by the near-field beam, the supplementary high beam at least partially illuminating the area above the horizon.

[0046] However, in the unrestricted application of its function of writing on the ground, segmented beams need to be projected from the headlights at least 10m so that, given its speed, the driver has time to see and interpret the information. This 10m distance can correspond to an angle value below the horizon, depending on the height of the headlights on the vehicle when it is in motion. For example, in a sports car, the headlights will be about 60cm above the ground, meaning 10m corresponds to 3.44° below the horizon; as another example, for a standard passenger vehicle, the headlights are generally about 75cm above the ground, corresponding to an angle of 4.29° below the horizon. Finally, according to another example, for a 4x4 or SUV (semi-commercial vehicle), the headlights are generally about 90cm above the ground, and therefore in this case, 10m corresponds to 5.15°. Similarly, it is generally considered ineffective to project beyond 50m, or that an unattainable brightness is required to make the image clearly visible beyond 50m. For headlights positioned at 0.6m, 0.75m, and 0.9m above the ground, this 50m corresponds to 0.69°, 0.86°, and 1.03° below the horizontal, respectively. In summary, to cover the entire useful range of projection on the ground, it is necessary to cover an angular range below the horizontal from -0.6° to -5.5° or even -6°.

[0047] This arrangement allows functions displayed through its pictograms to be performed, which are very useful as a means of conveying information to, for example, a driver. Thus, arrows can be displayed illustratively on the traffic lane being driven into, so as to recall information about a desired turn or change of direction. Clearly, the invention is not limited to the shape of the pictograms.

[0048] The device can also be used to form other lighting functions through the aforementioned functions, particularly those related to adaptive beams, or in addition to those functions.

[0049] Vehicles may be equipped with the modules of the present invention, and preferably, the vehicles are also equipped with at least one additional module for projecting at least one other beam of light. The headlights may also be complex and comprise multiple modules, which may optionally share components.

[0050] According to the invention, certain refractive interfaces are placed at the same distance around the pupil. The expression "substantially the same" means that similar distances are permissible in the target application, i.e., sufficiently similar dimensions to produce the desired technical effect, particularly in terms of resolution. For example, with respect to distances d1 and d2, these distances are considered substantially the same if the value of one differs from the value of the other by no more than 10%. Illustrated, they can be equal to 10 mm + / - 1 mm. For example, with respect to distances d3 and d4, these distances are considered substantially the same if the value of one differs from the value of the other by no more than 20%.

[0051] Figure 1 Vehicle 1 is shown, with beam 2 projected in front of it. Figure 1 The ability to perform writing on the ground within area 3 is also demonstrated. This capability can be particularly advantageously used to generate pictographic patterns. Only one pictogram can be projected. Multiple pictograms can also be displayed simultaneously or alternately. In the ADB case, the ability to write on the ground can also be activated.

[0052] The projected light beam can be generated by a light source 4, which is schematically shown in the following figure, and preferably by multiple emitting elements. It should be noted that the multiple emitting elements can be controlled to be selectively activated. This means that all emitting elements do not necessarily have to be active simultaneously, i.e., emitting light. This feature allows the shape of the generated light beam to be modulated. If the emitting elements are not activated, their image (e.g., an image projected by an optical device) will not exist. Therefore, an illuminance vacuum is formed throughout the generated light beam.

[0053] Source 4 preferably includes a carrier on one side, which carries, for example, a selectively activated emitting element based on LED technology, as described in detail below.

[0054] As in Figure 2A As particularly schematically shown, the light source 4 is advantageously centered on and perpendicular to the optical axis of the optical device, which is represented herein by the lens group (hereinafter units 5 and 6). The optical axis can be oriented substantially horizontally.

[0055] Light source 4 can specifically take the form of a matrix array of emitting elements that can be individually activated, so that any one of the emitting elements can be turned off or on. Therefore, the shape of the generated beam can be varied with a very high degree of flexibility. A matrix array of emitting elements, for example forming 2464 or more pixels, can be used, arranged in rows and columns, such as 28 rows and 88 or 132 columns, simply by illustration.

[0056] As is known per se, the present invention may use light-emitting diodes (also commonly referred to as LEDs) as light sources. These may be one or more organic LEDs. These LEDs may specifically include at least one semiconductor chip capable of emitting light. Furthermore, the expression "light source" herein is understood to mean at least a set of basic light sources, such as LEDs capable of generating flux that causes at least one beam of light to be output from the module of the present invention. In an advantageous embodiment, the exit surface of the source has a rectangular cross-section, which is common for LED chips.

[0057] The light source preferably comprises a monolithic matrix array of at least one electroluminescent element, also referred to as a monolithic matrix array. In the monolithic matrix array, the electroluminescent elements are grown from or have been transferred onto a common substrate and are electrically connected so that they can be selectively, individually, or in the form of a subset of the electroluminescent elements. The substrate may be made primarily of semiconductor. The substrate may include one or more other materials, such as non-semiconductor materials. Each electroluminescent element or group of electroluminescent elements can thus form a light-emitting pixel and be able to emit light when their material is powered. Compared to conventional light-emitting diodes used for soldering to printed circuit boards, this configuration of a monolithic matrix array allows selectively activated pixels to be arranged very close to each other. In the context of the invention, the monolithic matrix array includes electroluminescent elements whose main elongated dimension, i.e., height, is substantially perpendicular to the common substrate, and this height is at most equal to one micrometer.

[0058] Advantageously, one or more monolithic matrix arrays capable of emitting light can be coupled to a control unit for controlling the light emission of a pixelated source. Therefore, the control unit can control (or drive) the light emitting device to generate and / or project pixelated beams. The control unit can be integrated into the light emitting device. The control unit can be mounted on one or more matrix arrays, thus forming a light emitting module. The control unit may include a central processing unit coupled to a memory storing a computer program, the computer program including instructions that allow the processor to execute steps to generate signals that allow the light source to be controlled. Therefore, the control unit can, for example, control the light emission of each pixel of the matrix array individually. Furthermore, the brightness obtained by the multiple electroluminescent elements is at least 60 Cd / mm². 2 And preferably at least 80 Cd / mm 2 .

[0059] The control unit can form an electronic device capable of controlling an electroluminescent element. The control unit can be an integrated circuit. An integrated circuit, also known as an electronic chip, is an electronic component that reproduces one or more electronic functions and can combine various types of basic electronic components, for example, in a limited volume (i.e., on a small wafer). This makes the circuit easy to implement. An integrated circuit can be, for example, an ASIC or an ASSP. An ASIC (Application-Specific Integrated Circuit) is an integrated circuit developed for at least one specific application (i.e., for a customer). Therefore, an ASIC is a specialized (microelectronic) integrated circuit. Generally, it performs a large number of unique or custom functions. An ASSP (Application-Specific Standard Product) is an integrated (microelectronic) electronic circuit that performs a large number of functions to meet the needs of general standardized applications. An ASIC is designed for more specific (specific) requirements than an ASSP. The monolithic matrix array is powered by an electronic device, which itself is powered using at least one connector, for example, to which it is connected. The power supply can be internal or external to the device according to the invention. The electronic device supplies power to the light source. The electronic device is thus able to control the light source.

[0060] According to the invention, the light source preferably comprises at least one monolithic matrix array, wherein its light-emitting elements protrude from a common substrate. This arrangement of elements can be formed by growth on the substrate, with each element individually grown from the substrate, or by any other manufacturing method, such as the transfer of elements using a transfer technique. Various arrangements of the electroluminescent elements can satisfy this limitation of the monolithic matrix array, provided that one of the major elongation dimensions of the electroluminescent elements is substantially perpendicular to the common substrate, and the spacing between pixels formed by one or more electrically grouped electroluminescent elements is small compared to the spacing required in known arrangements of flat, square chips soldered to a printed circuit board.

[0061] In particular, a light source according to one aspect of the invention may include a plurality of individual electroluminescent elements, which are individually grown from a substrate but electrically connected so as to be selectively activated in a subset of rods that can be activated simultaneously.

[0062] According to one embodiment (not shown), the monolithic matrix array includes multiple electroluminescent elements having sub-millimeter dimensions, or even dimensions less than 10 μm, protruding from the substrate to form rods with hexagonal cross-sections. When the light source is in place within the housing, the light-emitting rods extend parallel to the optical axis of the light-emitting module.

[0063] Specifically, these light-emitting rods are grouped into multiple selectively activated segments via electrical connections dedicated to each set. The electroluminescent rods are embedded in a first side of a substrate. Each electroluminescent rod, formed herein using gallium nitride (GaN), protrudes vertically or substantially vertically from the substrate, which is silicon-based, although other materials such as silicon carbide may be used without departing from the scope of the invention. By way of example, the electroluminescent rods may be made of an alloy of aluminum nitride and gallium nitride (AlGaN), or an alloy of aluminum, indium, and gallium phosphide (AlInGaP). Each electroluminescent rod extends along an axis defining its height, with the base of each rod positioned in a plane on the front side of the substrate.

[0064] According to another embodiment (not shown), the monolithic matrix array may include electroluminescent elements formed from layers of electroluminescent elements, particularly a first layer of n-doped GaN and a second layer of p-doped GaN epitaxially grown on a single substrate (e.g., a substrate made of silicon carbide), and the electroluminescent element layers are sliced ​​(by grinding and / or ablation) to form multiple pixels located on the same substrate. The result of this design is that multiple electroluminescent blocks are located on the same substrate and are electrically connected, such that each of the electroluminescent blocks can be selectively activated.

[0065] In one example of an implementation according to this other embodiment, the substrate of the monolithic matrix array may have a thickness between 100 μm and 800 μm, and particularly equal to 200 μm; each block may have a length and a width, each length and width being between 50 μm and 500 μm, and preferably between 100 μm and 200 μm. In a variation, the length and width are equal. The height of each block is less than 500 μm, and preferably less than 300 μm. Finally, the exit surface of each block may be formed via the substrate on the side opposite to the side on which epitaxial growth is performed. The distance separating consecutive pixels may be less than 1 μm, particularly less than 500 μm, and preferably less than 200 μm.

[0066] For a single chip of an electroluminescent block:

[0067] The number of pixels can range from 250 to several thousand. A typical value is around one thousand pixels.

[0068] Their overall shape is often square, but it can also be rectangular. Their aspect ratio is generally between 1:1 and 1:5.

[0069] In the current state of the art, the size of a unit pixel (square in all known cases, but can be rectangular) is between 100 μm and 300 μm or smaller (on the order of 40 μm in the latest generations of LEDs).

[0070] According to another embodiment (not shown), it can be applied to electroluminescent rods protruding from the same substrate, i.e., rods as described above, and electroluminescent blocks obtained by slicing electroluminescent layers superimposed on the same substrate. The monolithic matrix array may further include a layer of polymer in which the electroluminescent elements are at least partially embedded. Thus, the layer may extend over the entire extent of the substrate or only around a given group of electroluminescent elements. In particular, a silicone-based polymer forms a protective layer that allows the electroluminescent elements to be protected without impeding light diffusion. Additionally, a wavelength conversion device, such as a light emitter, can be incorporated into the polymer layer, capable of absorbing at least some of the light emitted by one of the elements and converting at least some of the absorbed excitation light into emitted light having a wavelength different from that of the excitation light. The light emitter may be embedded in the body of the polymer or disposed on the surface of the polymer layer. Phosphors may also be vacuum-deposited on a semiconductor chip without a polymer layer. The light source may further include a coating of reflective material to deflect light toward the emitting surface of the pixelated source.

[0071] Submillimeter-sized electroluminescent elements define a given emission region in a plane substantially parallel to the substrate. It should be understood that the shape of this emission region depends on the number and arrangement of the electroluminescent elements forming it. Therefore, a substantially rectangular emission region can be defined; however, it should be understood that the emission region can vary and can be of any shape without departing from the scope of the invention.

[0072] The selectively activated emitting element can be a secondary light source. For example, a primary light source can illuminate the surface of a mirror in a micromechanical device, such as a digital micromirror device, where selective reflection from the mirror forms the emission of secondary light that allows for pixel formation.

[0073] According to one possibility, the lateral sector covered by the field of view of the generated beam is greater than 14°, or even greater than or equal to 20° and / or preferably less than 30°.

[0074] By way of example, the matrix array of pixels from source 4 can have a rectangular shape, with an aspect ratio of at least 2 and / or at most 4 between the maximum and minimum dimensions.

[0075] Now refer to Figure 2A and Figure 2B A first embodiment of the projection system is described.

[0076] This configuration is the simplest of those illustrated. Specifically, the optical device comprises only three lenses. The first optical unit 5 is then composed of lens 51. The latter is advantageously a meniscus / convex lens. It can be made of crown glass. To limit the deviations it is prone to generate, its refractive index is advantageously relatively high, and for example at least equal to 1.65. This lens 51 can be used as a field lens. Its light intensity may be very low, or even zero.

[0077] In the illustrated embodiment, light generated by source 4 enters lens 51 directly. The light then passes through pupil 7, which acts as a diaphragm that preferably sets the aperture (to form a peripheral stop relative to the light), defining the aperture for light to pass through in the direction of the second optical unit 6. The latter comprises at least one double lens, here consisting of lens 61 and lens 62. Lens 61 is inherently divergent. It is taken as a biconcave lens here, but it can have other configurations that allow for negative light intensity: for example, a concave / planar or convex / concave configuration with suitable curvature can be a good alternative. Preferably, the lens is made of flint glass. Its refractive index is advantageously greater than or equal to 1.7.

[0078] The symmetry between the first optical unit 5 and the second optical unit 6 will be noted. More precisely, the exit refractive interface of the first optical unit 5 is located at a distance d1 from the pupil 7, and the refractive interface here is formed by the exit surface of the lens 51; in parallel, the incident refractive interface of the second optical unit 6 is located at a distance d2 from the opposite side of the pupil 7, and the refractive interface here is formed by the incident surface of the lens 61. The distances d1 and d2 are specified to be the same under the aforementioned conditions regarding dimensional tolerances.

[0079] The second lens 62 of the double lens of optical unit 6 is advantageously a converging lens; it may be made of crown glass and preferably has a high refractive index, advantageously greater than or equal to 1.5, or even 1.65.

[0080] exist Figure 2A In the illustration, lens 62 is biconvex, but other arrangements that allow for the desired convergence are also possible, such as a plano-convex lens or a concave / convex lens with a suitable curvature.

[0081] It should be noted that in this case, it is advantageous to alternate at least some flint glass and crown glass lenses in at least each double lens, as in the following embodiment.

[0082] Advantageously, at least some, and preferably all, of the refractive interfaces of the lens are spherical (or planar).

[0083] Figure 2B An example of the path of light from each pixel of light source 1 according to this embodiment is provided.

[0084] Figure 3A and 3B A variation of the above scenario is shown.

[0085] Therefore, in this configuration, the first optical unit 5 has a second lens 52 with converging properties. As described above, even though a biconvex lens is illustrated, other arrangements that ensure convergence are possible. In this configuration, the exit refractive interface of the first unit 5 is formed by the exit surface of the lens 52. d1 is then measured relative to this surface.

[0086] The path of the corresponding light ray is Figure 3B It is shown in the middle.

[0087] exist Figure 4A and Figure 4B In the illustrated case, optical unit 5 is more complex because three lenses 51, 52, and 53 are associated. Lens 51 can be equivalent to those described above with respect to other embodiments. As mentioned above, it can define the projection field. In this configuration, a double lens subsequently associates lenses 52 and 53.

[0088] Lens 52 is inherently converging; it is preferably made of crown glass and advantageously has a high refractive index, particularly at least 1.5, or even 1.65. (As in...) Figure 3A In the embodiment shown, it is biconvex, but other shapes are also possible.

[0089] Lens 53 is divergent; it can be made of flint glass; its refractive index can be at least 1.7. Here, it has a concave incident surface and a convex exit surface; however, as mentioned above, there are other methods to achieve a lens with negative intensity. In this case, the exit surface of lens 53 is used when determining the distance d1.

[0090] In this case, there are two double lenses that are positioned with a certain degree of symmetry about the pupil 7.

[0091] Advantageously, it is stipulated that the two bilenses have equal light intensities (this is considered to be the case when they are the same within 10%), so as to distribute it relative to the pupil 7.

[0092] also, Figure 4A The distances d3 and d4 are shown respectively between the incident surface of the first double lens and the pupil 7, and between the pupil 7 and the incident surface of the second lens 62 of the second optical unit's double lens. This further increases the symmetry of the system. Specifically, it allows for the distribution of flint glass lenses and crown glass lenses relative to the pupil 7. Preferably, the flint glass lenses have the same refractive index (within 10%). This also applies to the crown glass lenses of the two double lenses.

[0093] It should be noted that in the preferred configuration, the diverging flint glass lens is the element closest to the pupil 7, while the converging crown glass lens is the external element of this pair of lenses.

[0094] Figure 4B An example of the path taken by light in this configuration is shown.

[0095] Alternatively, the refractive index of lens 51 may be equal to (within 10%) the refractive index of the crown glass of the corresponding lens in the double lens.

[0096] Optionally, the device may include more than five lenses. In particular, the second optical unit may be equipped with at least one or more additional lenses following the double lens, and preferably having converging properties. Flint and crown glass lenses may also be used alternately.

[0097] The present invention is not limited to the above embodiments and extends to all embodiments covered by the claims.

Claims

1. An optical device for projecting a light beam, said optical device being able to interact with a pixelated light source (4) comprising a plurality of selectively activable emitting elements, characterized in that, The optical device comprises, in the direction of travel of the light rays, in succession, a first optical unit comprising an exit dioptric interface located at a first distance (dl) from the pupil, a pupil and a second optical unit comprising an entry dioptric interface located at a second distance (d2) from the pupil, the second distance (d2) being substantially identical to the first distance (dl), and the first optical unit comprising a converging lens and the second optical unit comprising a doublet, one of the lenses of the doublet being made of flint glass and being divergent, the other of the lenses of the doublet being made of crown glass and being convergent.

2. The optical device of claim 1, wherein, The first optical unit comprises a first converging lens forming the entry dioptric interface of the first optical unit, and a second converging lens immediately following the first converging lens.

3. The optical device of claim 2, wherein, The entry dioptric interface has a meniscus shape.

4. The optical device of any one of claims 2-3, wherein, The first optical unit comprises a divergent lens immediately following the second converging lens.

5. The optical device of claim 4, wherein, The second converging lens and the divergent lens form a doublet, one of the lenses of the doublet being made of crown glass and the other of the lenses of the doublet being made of flint glass.

6. The optical device of claim 5, wherein, The lenses of the doublet of the first optical unit and the lenses of the doublet of the second optical unit are alternating flint glass lenses and crown glass lenses in the direction of travel of the light rays.

7. The optical device of claim 4, wherein, The second converging lens comprises an entry dioptric interface located at a third distance (d3) from the pupil, and wherein the doublet of the second optical unit comprises an exit dioptric interface located at a fourth distance (d4) from the pupil, the third distance (d3) and the fourth distance (d4) being substantially identical.

8. The optical device of claim 4, wherein, The doublet of the first optical unit and the doublet of the second optical unit have the same light intensity.

9. The optical device of any one of claims 1-3, wherein, The first optical unit and / or the second optical unit comprise at least one flint glass lens having a refractive index of at least equal to 1.

6.

10. The optical device of claim 9, wherein, The first optical unit and / or the second optical unit comprise at least one flint glass lens having a refractive index of at least equal to 1.

7.

11. The optical device of claim 9, wherein, The first optical unit and / or the second optical unit comprise at least one flint glass lens having a refractive index of at least equal to 1.

8.

12. The optical device according to any one of claims 1-3, wherein the first optical unit and / or the second optical unit comprise at least one crown glass lens having a refractive index of at least equal to 1.

45.

13. The optical device according to claim 12, wherein the first optical unit and / or the second optical unit comprise at least one crown glass lens having a refractive index of at least equal to 1.

5.

14. The optical device according to claim 12, wherein the first optical unit and / or the second optical unit comprise at least one crown glass lens having a refractive index of at least equal to 1.

65.

15. The optical device according to any one of claims 1-3, having a numerical aperture of less than 1.

16. The optical device according to claim 15, having a numerical aperture of less than 0.

9.

17. The optical device of claim 15, having a numerical aperture less than or equal to 0.

75.

18. The optical device of any one of claims 1-3, wherein the flint glass lens has an Abbe number < 50, and / or the crown glass lens has an Abbe number greater than 45.

19. The optical device of claim 18, wherein the flint glass lens has an Abbe number < 45, and / or the crown glass lens has an Abbe number greater than 50.

20. A module comprising the optical device of any one of the preceding claims, and a pixelated light source equipped with a plurality of selectively activatable emission elements and configured to emit a segmented light beam.

21. The module of claim 20, wherein, The light beam performs a function by which it writes on the ground.

22. The module of any of claims 20-21, wherein, The light beam forms at least a portion of an entire high beam.

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