Optical module, particularly for motor vehicles, and its control system

Abstract

Optical Module, Particularly for Motor Vehicles, and its Control Method. The invention relates to an optical module (20), particularly for motor vehicles, characterized in that it comprises a light source (21) composed of a plurality of selectively addressable light zones, each of the plurality of light zones being intended to emit a first light beam (22) around an optical axis (Y), an optical system (23) intended to receive the first incident light beams (22) emitted by the plurality of light zones and to form second output light beams (24) from the first incident light beams (22), an optical element (25) having one degree of freedom with respect to the optical axis (Y) and configured to deflect at least a portion of the first light beams (22) or at least a portion of the second light beams (24). (Figure 2)

Description

Title of the invention: Optical module, particularly for motor vehicles, and its control method

[0001] The present invention relates to the fields of lighting and / or signaling, in particular for motor vehicles, and more specifically concerns an optical module and its control method.

[0002] In what follows, the invention will be described in its application to the automotive field. Of course, the invention can also be applied in other technical fields implementing lighting and visual signaling.

[0003] In the field of optical modules for motor vehicles, various types of modules are known, intended for road lighting or signaling, among which we find essentially: - position lights, of low intensity and range; - fog lights; - dipped headlights, or dipped headlights, of significant intensity and with a range on the road of approximately 70 meters; - signaling devices, for example intended to display pictograms.

[0004] An optical module typically includes a light source, for example an LED (Light Emitting Diode). An LED is an optoelectronic device that emits light when an electric current passes through it. The light source emits a luminous area, or light radiation, along an optical axis. An optical module also includes an optical system arranged to receive the incident light radiation emitted by the luminous area and to form an output image from the incident light radiation.

[0005] Currently, the light source in optical modules is increasingly becoming highly pixelated. In other words, the light source is composed of a very large number of LEDs to form an extremely high-resolution beam. Using a highly pixelated light source, for example, on the order of 20,000 pixels, makes it possible, for instance, to assign a visual signature to a motor vehicle or to display a pictogram with very high resolution. However, such a light source has the disadvantage of resulting in an image with visible pixelation.

[0006] Figure 1 represents, on the left side of the figure, a highly pixelated light source 10 in a very schematic way. By way of example, such a set of pixels 11 arranged in rows and columns to form a matrix can be an LED pixelated or composed of a plurality of LEDs arranged side by side. As can be seen, the LEDs are separated in pairs by a space of 12. On the right side of the figure, we can see the image output from a prior art optical module. This image is pixelated and lacks sharpness.

[0007] In addition, in the field of lighting, it is also desirable to be able to form a selective beam with dark areas where there are vehicles or people who should not be dazzled, or conversely to be able to form a selective beam with an illuminated area in a dark area in order to compensate for a pixel defect which may negatively impact a row or column of the matrix.

[0008] The invention aims to address the drawbacks of the prior art by proposing a new optical module that improves the resolution of the formed images while simultaneously providing a harmonious rendering. In addition to improving road illumination or displaying pictograms, the invention ensures a reduction, or even elimination, of the discomfort caused by excessive brightness for oncoming or following drivers, and also addresses potential pixel failures. The optical module of the invention thus provides excellent visual quality illumination with a harmonious rendering and adapts the lighting level to the specific need.

[0009] To this end, the invention relates to an optical module, particularly for motor vehicles, comprising: - a light source composed of a plurality of selectively addressable light zones, each of the plurality of light zones being designed to emit a first beam of light around an optical axis, - an optical system designed to receive the first incident light rays emitted by the plurality of luminous zones and to form second output light rays from the first incident light rays, - an optical element having one degree of freedom with respect to the optical axis and configured to deflect at least part of the first light rays or at least part of the second light rays.

[0010] Thanks to these characteristics, the beam from the highly pixelated light source is deflected, and this deflection is transferred to the final pattern. The rendering of the final pattern is more harmonious. This also results in a visual increase in the pixelation of the beam.

[0011] In one embodiment of the optical module according to the invention, the degree of freedom is a translational degree of freedom perpendicular to the optical axis. The translational degree of freedom may be along a longitudinal or vertical axis. This degree of Translational freedom allows for beam scanning to homogenize the beam from the highly pixelated light source. Reference to the longitudinal or vertical axis is determined by the optical module's orientation, corresponding to its normal use.

[0012] In another embodiment of the optical module according to the invention, the degree of freedom is a rotational degree of freedom about the optical axis. By rotating the optical element, the rendering of the final pattern is more harmonious, and the visual defects related to the high pixelation of the light source are eliminated.

[0013] Advantageously, the optical element is a prism with a circular cross-section in a plane perpendicular to the optical axis, centered on the optical axis, the prism extending between an entrance face and an exit face, the exit face forming an angle between 0.04° and 0.32°, preferably 0.16°, with respect to the entrance face. This configuration makes it possible to reduce visual defects and to multiply the number of pixels relative to the number of pixels of the light source.

[0014] Advantageously, the optical system comprises a lens with a circular cross-section in a plane perpendicular to the optical axis, and the optical element is the lens with a circular cross-section. It is understood that, in this way, the optical system and the optical element form a single element. This feature has the advantage of not requiring the addition of an extra optical component and of using an existing optical system to set it in motion according to the invention.

[0015] According to the invention, the optical module may further include a control device for at least one of the light source and the optical element. The control device synchronizes the activation of the light source according to the positioning of the optical element. This contributes to obtaining a sharp and high-resolution image.

[0016] The invention also covers a lighting and / or signaling device for a motor vehicle comprising such an optical module.

[0017] The invention also relates to a method for controlling such an optical module, comprising the following steps: - emission of at least some of the initial light radiation around the optical axis, - setting the optical element in motion according to the degree of freedom with respect to the optical axis.

[0018] In an optional embodiment of the method of the invention, the addressing step is carried out according to a position of the optical element and the second light rays to be formed.

[0019] In an advantageous embodiment of the process of the invention, the step of emitting the first light rays is carried out as a function of a position of the optical element.

[0020] Other features and advantages of the invention will become apparent from the following description on the one hand, and from several illustrative and non-limiting examples of embodiments given with reference to the accompanying schematic drawings on the other hand, in which:

[0021] [Fig. 1] schematically represents a highly pixelated light source and the rendering of the image output from a prior art optical module,

[0022] [Fig.2] schematically represents an optical module according to the invention,

[0023] [Fig.3] schematically represents a first embodiment of a module optics according to the invention,

[0024] [Fig.4] schematically represents the first embodiment of an optical module according to the invention in different usage configurations,

[0025] [Fig.5] schematically represents a second embodiment of an optical module according to the invention,

[0026] [Fig.6] schematically represents the second embodiment of an optical module according to the invention,

[0027] [Fig.7] schematically represents an example of second light rays resulting from a control of the optical module according to the invention.

[0028] The features, variants, and different embodiments of the invention, as described or as they will be presented in the detailed description that follows, can be combined in various ways, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be conceived comprising only a selection of features described hereafter in isolation from the other described features, if this selection of features is sufficient to confer a technical advantage and / or to differentiate the invention from the prior art.

[0029] For the sake of clarity, the same elements are designated by the same references in the different figures.

[0030] Figure 1 schematically represents a highly pixelated light source and the image rendering at the output of a prior art optical module. It was presented in the introduction.

[0031] Figure 2 schematically represents an optical module 20 according to the principle of the invention. The optical module 20, particularly suitable for a motor vehicle, comprises a light source 21. The light source 21 is composed of a plurality of selectively addressable light zones 11. This light source 21 is highly pixelated, meaning it is composed of a very large number of pixels, on the order of 1,000 to 1,000,000 pixels, for example 20,000 pixels, in order to form an extremely high-resolution beam. The light source 21 is typically arranged in rows and columns to form a matrix.

[0032] However, the light source 21 can also consist of a line of light zones.

[0033] Thus, the light source 21 can be a pixelated LED or a plurality of LEDs arranged side by side. As shown in [Fig. 1], the LEDs are separated in pairs by a space, leading, in prior art lighting solutions, to a pixelated rendering and a lack of sharpness.

[0034] The optical module may include a light source control unit to activate and / or deactivate it.

[0035] Each of the plurality of luminous zones is intended to emit a first light radiation 22 around an optical axis Y.

[0036] The optical module of the invention further comprises an optical system 23 for receiving the first incident light beams 22 emitted by the plurality of luminous zones 11. The optical system 23 is designed to form, at the output, second output light beams 24 from the first incident light beams 22. Traditionally, the optical system 23 may comprise one or more lenses, each of which receives the incident beams and deflects them according to the configuration of the optical system 23. It is this set of lenses that enables the projection of the beam onto the road.

[0037] According to the invention, the optical module 20 comprises an optical element 25 having one degree of freedom with respect to the optical axis Y. The optical element 25 is configured to deflect at least a part of the first light rays 22 or at least a part of the second light rays 24. This feature will be detailed below based on the description of two embodiments of the invention.

[0038] Compared to a prior art optical module without light beam deviation, the optical module of the invention creates a deviation of the beam from the highly pixelated light source and directs this deviation to the periphery of the final pattern, which we will also call the illuminated area. This results in a visual increase in beam pixelation and a more harmonious rendering. In other words, the optical module of the invention takes advantage of the high pixelation of the light source to produce a high-resolution final pattern on the one hand, and on the other hand counterbalances the negative effect of this high pixelation of the light source to homogenize the final pattern.

[0039] The optical module of the invention advantageously comprises a device 26 for moving the optical element 25 according to the degree of freedom with respect to the optical axis. As will be explained below, the device 26 for moving the optical element 25 can be coupled with the light source control unit to activate and / or deactivate it according to the position of the optical element 25.

[0040] Figure 3 schematically represents a first embodiment of an optical module 30 according to the invention. In this embodiment, the degree of freedom is a translational degree of freedom perpendicular to the optical axis Y. In the figure, the translational degree of freedom is along a vertical axis Z. However, the invention also covers the case where the translational degree of freedom is along a longitudinal axis X. It can also be noted that the first embodiment of the optical module 30 also relates to an optical element 25 having several degrees of freedom with respect to the optical axis Y, for example, a translational degree of freedom along the longitudinal axis X and a translational degree of freedom along the vertical axis Z, or any other translational degree of freedom along an axis parallel to the plane formed by the axes X and Z.

[0041] Figure 3 schematically represents the light source 21 is highly pixelated, and the optical system 23 is shown. Here, the optical system is very schematically represented by a lens. The first light ray from the light source 21 leaves the optical system 23 as a second light ray 24. The second light ray 24 is incident on the optical element 25. The optical element 25 is, for example, a lens with a circular cross-section in a plane perpendicular to the optical axis Y. As shown (and without limiting the invention), the optical element 25 has one degree of freedom in translation along the Z axis. In other words, the optical element 25 oscillates between different vertical positions along the Z axis.To achieve this, the optical module may include a mechanical structure for oscillatory motion, and the optical element 25 may be mounted on this mechanical structure around its reference position centered on the Y-axis. This wobbling motion, also known as the oscillation or flickering motion of the optical element, can be continuous throughout the entire operating time or temporary, for a period shorter than the full operating time. This movement of the optical element 25 results in a plurality of different locations for the second, offset light beams. This means that the optical module of the invention offers a more harmonious and homogeneous final pattern after averaging the different locations of the output beams.

[0042] This particularly advantageous feature of the invention is illustrated in [Fig.4],

[0043] Figure 4 schematically represents the first embodiment of an optical module 30 according to the invention in different operating configurations. The optical module shown in Figure 4 corresponds to the optical module 30 shown in conjunction with Figure 3. Four operating configurations are illustrated schematically to facilitate understanding of the invention. Configurations C1 and C2 correspond to the movement of the optical element 25 by translation along the X-axis. Configurations C3 and C4 correspond to the movement of the optical element 25 by translation along the Z-axis. Configurations C1 and C3 each correspond to a wobbling of the optical element 25, respectively along the X-axis and the Z-axis.Configurations C2 and C4 correspond to a particular use case in which a portion of the light source has a defect and the optical module of the invention compensates for this defect by moving the optical element 25.

[0044] In the configurations shown, the light source is a pixelated LED composed of three columns of pixels 41, 42, 43. For each configuration, four sub-configurations are shown. Sub-configuration S0 corresponds to the final pattern for a so-called reference light radiation.

[0045] In configuration C1, the optical element 25 is movable in translation along the X-axis. In subconfiguration S1, the optical element 25 has translated half a column along the X-axis in a first direction, denoted X+. The entire final pattern is thus shifted along X+ (i.e., to the right of [Fig. 4]). Column 41 is therefore half illuminated. And a half-column, to the right of column 43, initially unilluminated in the reference position S0, is now illuminated.

[0046] In subconfiguration S2, the optical element 25 has been translated by half a column along the X-axis in a second direction, denoted X, opposite to the first direction X+. The entire final pattern is thus shifted along X (i.e., to the left of [Fig. 4]). Column 43 is therefore half illuminated. And a half-column, to the left of column 41, initially unilluminated in the reference position S0, is now illuminated.

[0047] By repeating the translational movement (X+, X), the visual rendering of subconfiguration S3 is obtained. The initially illuminated areas remain illuminated, and the initially unilluminated areas become illuminated. This offers a dual advantage: firstly, the spaces between the LEDs are no longer visible due to the offset of the output beams, thus providing a low-pixelation or non-pixelated rendering and a sharp final pattern; and secondly, by offsetting the output beams, a multiplication of the pixels along the X axis. The invention makes it possible to increase the quality of the final pattern perceived by the human eye.

[0048] The same principle applies to the C3 configuration, with the difference that in the C3 configuration, the translation takes place along the Z axis.

[0049] In configuration C2, column 42 is defective. This column does not produce any light. It is therefore desirable to overcome this defect. Thanks to the invention, by successive translations of the optical element 25 along X+ and along X, and thus by shifting the output beams, the defective column appears visually as an illuminated column.

[0050] Alternatively, column 42 can be an operational column, but occasionally it may be desirable for this column to remain dark, for example, to limit glare for a person located in that area of ​​the final pattern. In this case, the light source control unit can be configured to selectively deactivate the illuminated areas assigned to column 42 according to the position of the optical element 25. This means that column 42 would be temporarily deactivated, as well as its two adjacent columns 41 and 43, which would appear illuminated in the final pattern due to the wobbling effect but would not contribute to the (undesired) illumination of column 42.

[0051] In configuration C4, it is a line that is defective. This line does not produce any light. It is therefore desirable to overcome this defect. Thanks to the invention, and in a manner similar to what has been described above, by successive translations of the optical element 25 along Z+ and along Z, and thus by shifting the output beams, the defective line appears visually as an illuminated line.

[0052] Advantageously, the optical system 23 comprises a lens with a circular cross-section in a plane perpendicular to the optical axis, and the optical element 25 is the lens with a circular cross-section. By proceeding in this manner, a translational motion with a certain frequency is integrated into the existing optics, thus resulting in a homogenization of the final pattern.

[0053] Figure 5 schematically represents a second embodiment of an optical module 40 according to the invention. In this second embodiment, the degree of freedom is a rotational degree of freedom about the optical axis Y. In other words, the optical element 25 is rotated about the Y axis to deflect the incident light rays.

[0054] The optical element 25 is a prism with a circular cross-section in a plane perpendicular to the optical axis, centered on the optical axis Y. The prism is made of transparent material. The prism extends between an entrance face 31 and an exit face 32. The face of The output 32 forms an angle Al between 0.04° and 0.32°, preferably 0.16°, with respect to the input face 31. For example, for a prism with a refractive index between 1.5 and 1.6 (such as a glass prism), the angle Al is advantageously 0.16°. The deviation of the output beam (corresponding to angle A2) is 0.08°. This value of radiation deviation typically corresponds, when projected onto the final pattern, to the inter-pixel value of the highly pixelated light source.

[0055] In one embodiment of the invention, the light source is continuously illuminated and the prism is continuously rotated around the Y-axis at high speed (at least 50 revolutions per second). The combination of the continuous rotation of the prism and the existence of the angle Al results in a spatial modulation that visually produces a larger final pattern. More precisely, the eye perceives a higher number of pixels, and the final pattern appears more homogenized and sharper.

[0056] Figure 6 schematically represents the second embodiment of the optical module 40 according to the invention. The light source is not shown in this figure. Along the path of the radiation, the optical system 23 comprises several lenses, and downstream of the optical system is the rotating optical element about the Y-axis. It can be noted that, alternatively, the prism can be integrated into one of the circular lenses of the optical system 23.

[0057] Although not shown, the optical module according to the invention may include a control device for the movement of the optical element and the light source. This control device makes it possible to synchronize the lighting of the LEDs of the light source according to the position of the optical element 25. This specific control is described in relation to [Fig. 7].

[0058] The invention also covers a method for controlling an optical module 40 comprising the following steps: - emission (step 100) of at least a portion of the first light radiations 22 around the optical axis Y, - setting in motion (step 110) of the optical element 25.

[0059] As explained above, performing these two steps deflects the output beams. Thanks to this deflection, the inter-pixel gap is no longer visible in the final image. The pixels appear contiguous, and the rendering quality is improved.

[0060] Furthermore, during emission step 100, it is possible to emit all or part of the initial light radiation. This allows the user to choose which portion(s) of the light source is / are to be activated or deactivated. This allows the lighting level to be adapted to the specific need.

[0061] Advantageously, the step 100 of emitting part of the first radiations, that is to say the addressing of at least one among the plurality of luminous zones, is carried out according to a position of the optical element 25 and the second light radiations 24 to be formed.

[0062] In the example of Figures 3 and 4, target positions of the optical element 25 correspond to desired positions for the final pattern. Advantageously, the emission step 100 of a portion of the initial radiation occurs while the position of the optical element 25 is within a margin around each target position. Advantageously, this margin is less than + / -10% of the full oscillation amplitude, i.e., within this range, preferably less than + / -5%, and even more preferably less than + / -1%. This latter value allows for obtaining precise final patterns. A larger margin facilitates a high luminous flux in the final pattern. It should be noted that the margin can be asymmetrical around said target positions and that it can differ from one target position to another.

[0063] Figure 7 schematically represents an example of secondary light beams resulting from the control of the optical module 40 according to the invention. The light source 21 is a highly pixelated light source. For the sake of clarity, only four pixels are shown.

[0064] The final pattern is represented according to a sequence of five instants: T0, T1, T2, T3, T4. At T0, step 100 is implemented, and the first light rays 22 are emitted around the optical axis Y. At T1, the final pattern is seen for a 0° rotation of the prism. The shape of the final pattern is related to the angle Al of the prism and the deviation of the output beam it generates. At T2, the prism has rotated by 90°. The final pattern seen at T1 has also rotated by 90°. At T3, the prism rotated an additional 90° relative to T2, meaning the final pattern was rotated 180° relative to the final pattern at TL. At T4, the prism rotated an additional 90° relative to T3, meaning the final pattern was rotated 270° relative to the final pattern at TL. Averaging the final patterns at T1, T2, T3, and T4 yields the final pattern on the right of the figure, in which the inter-pixel spaces are no longer visible. The resulting image is sharp and resolved.

[0065] In order to guarantee the sharpness of the final image, it is necessary to synchronize the activation of the light source according to the position of the prism. This is step 100, the emission of the first light rays 22 around the optical axis Y, which must be carried out according to the position of the optical element.

[0066] Indeed, the light source must be illuminated at certain positions of the prism to improve the imaging function of the optical module. To achieve this, in an advantageous embodiment of the invention, step 100 of emitting the first light rays is carried out at predetermined positions of the prism, by For example, every 90° (+ / - 5°) relative to a reference position (e.g., the position of the prism at T0, T1). Thus, step 100, the emission of the first light rays, is carried out while the prism's rotation angle is between -5° and 5°, then between 85° and 95°, then between 175° and 185°, then between 265° and 275°, then again between -5° and 5°, and so on. Other angular margin values ​​around the prism's rotation angle at T1, T2, T3, and T4 are possible for step 100, the emission of the first light rays. Advantageously, this angular margin is less than + / -10°, that is, within this range, preferably less than + / -5°, and even more preferably less than + / -1°. This latter value allows for precise final patterns. A larger angular margin facilitates high light flux in the final pattern.It should be noted that the margin can be asymmetrical around the aforementioned prism rotation angles at T1, T2, T3, T4, and that it can be different from one rotation angle to another.

[0067] By proceeding in this way, a final pattern is obtained that is less pixelated while generating an image with a visual increase in the number of pixels and a homogeneous and harmonious rendering.

[0068] Of course, the invention is not limited to the examples just described, and many modifications can be made to these examples without departing from the scope of the invention. In particular, the features of different embodiments of the invention can be combined to carry out the invention, provided that these embodiments are not incompatible with each other.

Claims

Demands

1. Optical module (20, 30, 40), particularly for motor vehicle, characterized in that it comprises: - a light source (21) composed of a plurality of selectively addressable light zones (11), each of the plurality of light zones being intended to emit a first light beam (22) around an optical axis (Y), - an optical system (23) intended to receive the first incident light beams (22) emitted by the plurality of light zones (11) and to form second output light beams (24) from the first incident light beams (22), - an optical element (25) having one degree of freedom with respect to the optical axis (Y) and configured to deflect at least a part of the first light beams (22) or at least a part of the second light beams (24).

2. Optical module (20, 30) according to claim 1, wherein the degree of freedom is a translational degree of freedom perpendicular to the optical axis (Y), in particular along a longitudinal (X) or vertical (Z) axis.

3. Optical module (20, 40) according to claim 1, wherein the degree of freedom is a rotational degree of freedom about the optical axis (Y).

4. Optical module (20, 40) according to claim 3, wherein the optical element (25) is a prism of circular cross-section in a plane perpendicular to the optical axis (Y), centered on the optical axis (Y), the prism extending between an input face (31) and an output face (32), the output face (32) forming an angle (Al) between 0.04° and 0.32°, preferably 0.16°, with respect to the input face (31).

5. Optical module (20, 30) according to any one of claims 1 to 4, wherein the optical system comprises a lens of circular cross-section in a plane perpendicular to the optical axis (Y), the optical element being the lens of circular cross-section.

6. Optical module (20, 30, 40) according to any one of claims 1 to 5, further comprising a control device for at least one of the light source and the optical element.

7. Lighting and / or signaling device for motor vehicle comprising an optical module (20, 30, 40) according to any one of claims 1 to 6.

8. Method of controlling an optical module (20, 30, 40) according to any one of claims 1 to 6, comprising the following steps: - emission (100) of at least a part of the first light rays around the optical axis, - setting in motion (110) the optical element according to the degree of freedom with respect to the optical axis (Y).

9. A control method according to claim 8, wherein the emission step (100) is carried out as a function of a position of the optical element (25) and the second light beams (24) to be formed.

10. A control method according to claim 8 or 9, wherein the step (100) of emitting the first light rays is carried out as a function of a position of the optical element (25).

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