FR3063260A1 - HOUSING FOR HEAD-UP DISPLAY OF MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a housing (20) for a head-up display (10) defining a housing (25) for receiving components (30, 41) of said head-up display. According to the invention, this housing comprises at least one textured wall (22) whose inner face has a plurality of projections protruding and / or recessed from the remainder of its surface, each of said reliefs extending in height or in depth on more than half a millimeter, and in the other two dimensions of space, less than one centimeter.

Description

Holder (s): VALEO COMFORT AND DRIVING ASSISTANCE Simplified joint-stock company.

Extension request (s)

Agent (s): VALEO COMFORT AND DRIVING ASSISTANCE.

(54) HOUSING FOR A HEAD-UP DISPLAY OF A MOTOR VEHICLE.

FR 3 063 260 - A1 (5 /) The invention relates to a housing (20) for a head-up display (10), which delimits a housing (25) for receiving components (30, 41) of said head-up display.

According to the invention, this housing comprises at least one textured wall (22) the inner face of which has a plurality of reliefs projecting and / or recessed from the rest of its surface, each of said reliefs extending in height or depth over more than half a millimeter, and, in the other two dimensions of space, over less than a centimeter.

Housing for head-up display of motor vehicle

Technical field to which the invention relates

The present invention relates generally to assistance devices for driving motor vehicles.

It relates more particularly to a box for a head-up display, which delimits a housing for receiving components of said head-up display.

It also relates to a head-up display comprising such a box.

TECHNOLOGICAL BACKGROUND

To make driving easier and safer, we want to avoid the driver being forced to look away from the road he is taking.

For this, it is known to use a head-up display, adapted to project elementary information (vehicle speed, direction to follow, ...) at the level of the driver's gaze.

Two types of head-up displays are known in particular.

The first type displays use an image forming device comprising a diffuser and a scanning unit designed to generate a light beam scanning an entrance face of the diffuser. The light beam at the outlet of the diffuser thus forms an image, which can then be projected into the field of vision of the driver of the vehicle.

Displays of the second type use an image-forming device comprising a light source and a screen which makes it possible to generate an image, which can be projected into the driver's field of vision.

Each of these head-up displays includes a housing that houses the image generation device as well as one or more mirrors. This box is designed to be fitted in the passenger compartment of the vehicle, more precisely in the dashboard of the vehicle, that is to say under the windshield.

To allow the passage of light from the image generation device to the outside of the housing (in the driver's field of vision), the housing has a main window.

The downside of this main window is that it allows outside light to enter the interior of the housing. This light is then likely to be reflected on the various components of the head-up display (mirrors, partially reflective blades, protective glass). It may then happen that this light disturbs the readability of the information projected by the head-up display, or even hinders the driving of the vehicle.

It is also found that the imaging device often has light leaks. These leaks may then reduce the contrast of the image seen by the driver, create halos of light, or make the internal components of the head-up display visible to the driver.

In summary, different sources of stray light can affect the quality of the image seen by the driver.

Object of the invention

In order to remedy the aforementioned drawbacks of the state of the art, the present invention proposes to modify the geometry of the housing so that the latter forms a sort of light trap.

More particularly, according to the invention, there is provided a housing as defined in the introduction, in which at least one textured wall is provided, the inner face of which has, on at least part of its surface, a plurality of protruding reliefs. and / or recessed with respect to the rest of its surface, which are distributed in the width and in the length of said textured wall (that is to say in the two dimensions of space which are defined by the internal face of the textured wall).

Preferably, each of said reliefs extends in height or in depth over more than half a millimeter, and, in the other two dimensions of space, over less than one centimeter.

The light emitted by the image forming device is intended to follow a path such that it leaves the housing without impacting the walls of the latter. However, this remains an ideal case and the light from the imaging path still illuminates the walls and components inside the system.

Stray lights, whether they come from the image forming device or from outside the system (sun or lamps in a tunnel for example) often impact the housing before being able to emerge from it. This is the reason why the interior surfaces of the boxes are generally designed to be absorbent, in order to reduce the effect of these stray lights.

Here, the invention further proposes to place reliefs for diffusing light in a large number of directions. In this way, the stray lights which impact the housing are partly absorbed and partly reflected in a large number of directions. Thanks to the distribution of the reliefs in the width and in the length of the textured wall, the light, once reflected, is then very likely, having regard to the size of the reliefs, to come again to impact another wall of the housing, so that it is once again partly absorbed and is partly diffused.

Thus, thanks to the invention, the effects of absorption and cascade scattering of light caused by the reliefs make it possible to considerably reduce the intensity of stray light capable of disturbing the reading of the information projected in the field of vision of the driver of the vehicle.

In the invention, the height or the depth of the reliefs (measured relative to the rest of the surface of the textured wall) is chosen so as to be sufficient for the reliefs to be able to effectively diffuse the light.

The dimensions of the reliefs in the other two dimensions of the space (in width and length, or in diameter, etc.) are chosen so that each relief has a reduced size, which makes it possible to distribute them a large number on the textured wall. The total surface area of the reliefs is thus maximized, so that the absorption and diffusion effects generated by the reliefs are optimized.

Other advantageous and non-limiting characteristics of the box according to the invention are as follows:

- Each relief has a height or a depth greater than a millimeter, and comprises a base located at the interior face of said textured wall, the smallest dimension of which is greater than one millimeter;

- the distribution of the reliefs is a function of the geometry of the housing;

- Said textured wall has at least ten distinct reliefs;

- at least one of the reliefs rises from the surface of said textured wall while thinning;

- at least one of the reliefs has a preferably truncated pyramid shape;

- at least one of the reliefs has a preferably truncated cone shape;

- At least one of the reliefs has a shape of a half-ball preferably truncated;

- The reliefs carried by said textured wall all have identical shapes;

- an outer wall is partially open by a window for the passage of light and said textured wall is located opposite the window;

- Said textured wall is made of plastic material loaded with metallic particles.

The invention also provides a head-up display for a motor vehicle, which comprises:

- a housing as mentioned above,

- an image generation device housed inside the housing, and

- a projection system adapted to deflect the light beam emitted by the image generation device for projecting said images into the field of vision of the driver of the motor vehicle.

Preferably:

- the projection system comprises at least one folding mirror which is located in the housing and which is adapted to deflect the light beam emitted by the image generation device,

- a protective screen is provided located along the path of said light beam between, on the one hand, the image generation device, and, on the other, said folding mirror, and

- the textured wall of the housing is located between the protective screen and said folding mirror.

Detailed description of an exemplary embodiment

The description which follows with reference to the accompanying drawings, given by way of nonlimiting examples, will make it clear what the invention consists of and how it can be carried out.

In the accompanying drawings:

- Figure 1 is a schematic view of a first embodiment of a head-up display according to the invention;

- Figure 2 is a schematic view of a second embodiment of a head-up display according to the invention;

- Figure 3 is a schematic view of a relief of the housing fitted to the head-up displays of Figures 1 and 2; and

- Figure 4 is a schematic view of a textured wall of the housing fitted to the head-up displays of Figures 1 and 2.

As a preliminary, it will be noted that the identical or similar elements of the different embodiments of the invention shown in the different figures will, as far as possible, be referenced by the same reference signs and will not be described each time.

In Figures 1 and 2, there are shown two embodiments of a head-up display 10 intended to equip a motor vehicle.

In these two embodiments, the head-up display 10 comprises a box 20 which houses, on the one hand, an image generation device 30, and, on the other hand, at least part of a system projection optics 40.

In the first embodiment illustrated in FIG. 1, the image generation device 30 is of the “light modulation” type. It comprises a screen 31, here a liquid crystal screen (or LCD for Liquid Crystal Display) with thin film transistors (or TFT for Thin-Film Transistor ¹ ′), which is controlled by a computer. It also includes a lighting device 32, which is here located at the rear of the screen 31 to backlight it. This lighting device 32 comprises a plurality of light-emitting diodes distributed behind the liquid crystals of the screen 31.

In the second embodiment illustrated in FIG. 2, the image generation device 30 is of the "emissive" type. It comprises a diffuser 33 and a scanning unit which is controlled by a computer so as to generate a light beam of variable direction scanning the rear face of the diffuser 33. The scanning unit more precisely comprises a beam forming module 34 and at least one mobile mirror 35, for example produced in the form of an electromechanical microsystem (or MEMS for MicroElectroMechanical System). The beam forming module 34 typically comprises three monochromatic light sources, such as laser sources, the respective light beams of which (monochromatic) are combined (for example using dichroic mirrors) in order to form a polychromatic light beam ( here laser) emitted at the output of the beam forming module 34. This light beam generated by the beam forming module 34 is directed towards the movable mirror 35, the orientation of which is controlled so that the reflected light beam ( by the movable mirror 35) scans the rear face of the diffuser 33.

In these two embodiments, the image generation device makes it possible, under the control of a computer, to generate an image that the optical projection system 40 will be able to project into the driver's field of vision when the gaze of this the latter is facing the road.

Thus, in these two embodiments, the optical projection system 40 is designed to project a virtual image Img into the field of vision of the driver of the vehicle, at a distance from the driver which is greater than that separating the driver from the windshield 100 (so that the driver's eyes do not have to do any accommodation work to clearly perceive the projected information).

The projection optical system 40 for this purpose comprises here a folding mirror 41 located on the path of the light flux emitted by the image generation device 30. It also here includes a combiner 42 placed in the field of vision of the driver of the vehicle.

The folding mirror 41 allows the image generated by the image generation device 30 to be returned to the combiner 42. Here it is flat but it could have a different shape, for example aspherical.

The combiner 42 makes it possible to reflect this image in such a way that it appears to the driver as if it were displayed at a great distance from the latter.

Here, this combiner 42 is formed by a partially reflective strip which is arranged in the passenger compartment of the motor vehicle, between the windshield 100 of the vehicle and the driver's eyes, and which is curved so as to enlarge the size of the virtual image Img seen by the driver.

Alternatively, the combiner could be formed by the windshield itself.

In the two embodiments shown in FIGS. 1 and 2, the box 20 is designed to house the folding mirror 41 and the image generation device 30.

To this end, it comprises external walls which delimit between them a housing 25 in which these components 30, 41 are housed.

It also includes means for securing these components and means for fixing the housing 20 to the motor vehicle.

The securing means (not shown) make it possible to rigidly fix the folding mirror 41 and the image generation device 30 in the housing 25.

The fixing means (not shown) make it possible to rigidly fix the box 20 to the motor vehicle, in the dashboard of the latter, under the windshield 100.

To allow the images generated by the image generation device 30 to be projected into the driver's field of vision, that is to say outside the housing 20, the latter has a main window 24 which is located in one of its external walls, here in its upper external wall 26.

This main window 24 could be closed by a protective screen. However, in the two embodiments shown in Figures 1 and 2, this main window 24 is left open.

On the other hand, a transparent protective screen 50 is provided inside the housing 25. Here, this protective screen 50 completely closes a window 21 formed in an interior wall 23 of the housing 20. It is located on the path of the light beam emitted by the image generation device 30 between, on one side, the device image generation 30, and, on the other, the folding mirror 41.

This protective screen 50 is designed to protect the image generation device 30 from objects which fall into the housing 20 through the main window 24 and from dust and other particles which are sure to enter the housing 20.

The internal wall 23 and the protective screen 50 which is embedded therein thus separate the housing 25 into two distinct parts, including a first part 25A which houses the image generation device 30 and a second part 25B which houses the mirror. folding 41.

Despite its position inside the housing 20, the protective screen 50 is still capable of receiving light rays from the outside and of reflecting them, at the risk of dazzling the conductor and illuminating the walls or components internal to the system (thus making them visible to the driver), or hampering the legibility of the information projected in the driver's field of vision.

In addition, despite the care taken in manufacturing the image generation device 30, it sometimes happens that light leaks out of the latter, thus risking disturbing the reading of the information projected in the driver's field of vision or '' illuminate the walls or components internal to the system, thus making them visible to the driver.

The invention therefore proposes to attenuate the effects generated by these stray lights.

For this, according to a particularly advantageous characteristic of the invention, at least one of the walls of the housing 20, called "textured wall 22", has an inner face 22A (located on the side of the housing 25) which has, on a at least part of its surface, a plurality of raised projections 27 and / or recesses (see FIG. 4).

This textured wall may be formed by one of the outer walls of the housing (that is to say one of the walls of the housing one of the faces of which faces outwards from the housing), or by the one of the interior partitions of this box.

Each of these reliefs 27 extends in height or in depth over more than half a millimeter, and, in the other two dimensions of space, over less than a centimeter.

Thanks to these dimensions, the reliefs are capable of diffusing stray light well which they receive in a large number of directions.

Preferably, the textured wall is black in color, to absorb a maximum of light. However, the presence of reliefs 27 makes it possible to significantly increase the total surface area of the interior face 22A of the textured wall 22. In this way, the reliefs 27 make it possible to optimize the absorption of stray light.

One could foresee that the relief 27 has multiple shapes.

Preferably, each relief 27 rises (if it is protruding) or sinks (if it is recessed) from the surface of the textured wall 22, becoming thinner.

Each relief may for example have a truncated cone shape, extending into a recess or projecting from the surface of the textured wall 22.

As a variant, each relief may have the shape of a half-ball or of a truncated half-ball, extending in a recess or projecting from the surface of the textured wall 22.

In the example shown in FIGS. 3 and 4, each relief 27 is in the form of a square and truncated pyramid, located projecting from the surface of the textured wall 22.

As shown in FIG. 3, the relief 27 extends in height relative to the surface of the textured wall 22 over a distance H1 greater than one millimeter, here approximately equal to 2.5 millimeters.

This relief 27 has a base 27A whose length L1 and width L2 are here equal and are greater than a millimeter. They are more precisely equal to 5 millimeters.

The angle formed between each of the lateral faces of the relief 27 and the base 27A is here equal to 45 degrees. The end face 27B of the relief 27 extends in parallel with the base 27A.

As shown in Figures 1 and 2, the textured wall 22 has a large number of reliefs (more than 10) which, as shown in Figure 4, are distributed both in the width of the textured wall 22 as in its length. In other words, if we consider the two main dimensions of the textured wall 22, it is expected that certain reliefs 27 will be offset with respect to each other both in one and in the other of these two main dimensions.

Provision could be made for the reliefs 27 to be regularly distributed over the entire surface of the textured wall 22, as shown in FIG. 4. However, in practice, the reliefs 27 will be distributed differently, depending on the results of calculations specific to the geometry of each type of housing, so as to optimize their light scattering effect.

Preferably, the reliefs 27 carried by the textured wall 22 all have identical shapes.

Preferably, several of the walls of the housing 20 are textured (that is to say bear reliefs). In this case, provision may be made for at least one of the textured walls to have reliefs of shapes different from those of the reliefs carried by the other textured walls.

Preferably, the wall located opposite the main window 24, that is to say the lower external wall of the housing 20, is textured. It is indeed she who is most likely to receive outside light. This wall is also located between the protective screen 50 and the folding mirror 41, so that it is also located on the path of light leaks from the image generation device 30.

Preferably, provision may be made for all of the internal faces delimiting the second part 25B of the housing 25 to have reliefs, in order to best reduce the discomfort of the conductor caused by stray lights.

Preferably also, the external walls of the housing 20 which are textured will be made of plastic material loaded with metallic particles.

The reliefs indeed make it possible to maximize the surface area for heat exchange between the housing 25 and the walls of the housing 20. Providing reliefs 27 which incorporate metallic particles then makes it possible to optimize the heat exchanges between the interior and the exterior. of the housing 20.

The present invention is not limited to the embodiment described and shown, but the skilled person will be able to make any variant according to his spirit.

In the figures, the faces of the reliefs 27 and the rest of the surface of the internal face 22A of the textured wall 22 are shown as being smooth. To further optimize their light scattering power, it could be provided that they are grainy (the diameters of the grains being less than 20 micrometers).

Claims (14)

1. Housing (20) for a head-up display (10), which delimits a housing (25) for receiving components (30, 41) of said head-up display (10), characterized in that it comprises at least one textured wall (22) whose inner face (22A) has, on at least part of its surface, a plurality of reliefs (27) projecting and / or recessed with respect to the rest of its surface, which are distributed in the width and length of said textured wall (22). 2. Housing (20) according to the preceding claim, in which each relief (27) extends in height (H1) or in depth over more than half a millimeter, and, in the two other dimensions of space, on less than a centimeter. 3. Housing (20) according to one of the preceding claims, wherein each relief (27) has a height (H1) or a depth greater than a millimeter, and comprises a base (27A) located at the inner face (22A ) of said textured wall (22), the smallest dimension (L1, L2) of which is greater than one millimeter. 4. Housing (20) according to one of the preceding claims, in which the distribution of the reliefs (27) is a function of the geometry of the housing (20). 5. Housing (20) according to one of the preceding claims, wherein said textured wall (22) has at least ten distinct reliefs (27). 6. Housing (20) according to one of the preceding claims, wherein at least one of the reliefs (27) rises from the surface of said textured wall (22) by thinning. 7. Housing (20) according to one of the preceding claims, in which at least one of the reliefs (27) has a preferably truncated pyramid shape. 8. Housing according to one of the preceding claims, wherein at least one of the reliefs has a preferably truncated cone shape. 9. Housing according to one of the preceding claims, in which at least one of the reliefs has the form of a preferably half-ball shaped. 10. Housing (20) according to one of the preceding claims, in which the reliefs (27) carried by said textured wall (22) all have identical shapes. 11. Housing (20) according to one of the preceding claims, comprising an outer wall (26) partially open by a window (21) for the passage of light and in which said textured wall (22) is located opposite the window (21). 12. Housing (20) according to one of the preceding claims, wherein said textured wall (22) is made of plastic loaded with metal particles. 13. Head-up display (10) for a motor vehicle, which comprises: - a housing (20) according to one of the preceding claims, - an image generation device (30) housed inside the housing (20), and - a projection system (40) adapted to deflect the light beam emitted by the image generation device (30) to project said images into the field of vision of the driver of the motor vehicle. 14. Head-up display (10) according to the preceding claim, in which: the projection system (40) comprises at least one folding mirror (41) which is located in the housing (20) and which is adapted to deflect the light beam emitted by the image generation device (30), - There is a protective screen (50) located along the path of said light beam between, on one side, the image generation device (30), and, on the other, said folding mirror (41) , and - the textured wall (22) of the housing (20) is located between the protective screen (50) and said folding mirror (41). 1/3 25B 2/3 3/3