WO2017178566A1

WO2017178566A1 - Image projection device for a head-up display, associated head-up display and method for producing such an image projection device.

Info

Publication number: WO2017178566A1
Application number: PCT/EP2017/058881
Authority: WO
Inventors: Laurent DELPIERRE; Pierre Mermillod; François GRANDCLERC
Original assignee: Valeo Comfort And Driving Assistance
Priority date: 2016-04-12
Filing date: 2017-04-12
Publication date: 2017-10-19
Also published as: FR3050040B1; FR3050040A1

Abstract

The invention relates to an image projection device (20) for a head-up display (1) comprising an image generation unit (22), and a reflecting unit (24) for reflecting generated images. According to the invention, the image projection device further comprises a protection conduit (40) linking said image generation unit and said image reflection unit, and comprising an outlet window (40C) for the reflected images, and said outlet window is closed by a transparent protective film (43).

Description

Image projection device for head-up display, associated head-up display and method of manufacturing such an image projection device

TECHNICAL FIELD TO WHICH THE INVENTION RELATES The present invention relates generally to the field of image projection devices for head-up display.

It relates more particularly to the protection elements of the optical elements included in image projection devices for head-up display.

It relates in particular to an image projection device for head-up display comprising an image generation unit, and a unit for returning the generated images.

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

Finally, it relates to a method of manufacturing such an image projection device.

BACKGROUND

The principle of head-up displays for vehicles is to project images, especially useful for driving, directly in the field of vision of a driver.

In general, the head-up displays comprise a combiner located in the driver's field of view, and an image projection device formed by an image generation unit adapted to generate images, and by a unit for returning images. generated adapted to return these images to the combiner.

The image projection device is generally integrated in the dashboard, while the combiner protrudes from the dashboard.

The optical elements used in the head-up displays, and in particular the possible mirrors provided in the image return units of the projection devices are particularly fragile.

To ensure the durability and efficiency of head-up displays, these optical elements should be protected from dust, moisture, or any object that the driver of the vehicle might place on the dashboard.

In addition, to form quality images in the field of view of the conductive, it is necessary to prevent light outside the image projection device, in particular the sun's rays, from degrading the images generated by this image projection device.

There is a head-up display, whose combiner is directly the windshield of the vehicle, and whose image projection device is formed by a liquid crystal display backlit by several light sources of LED type, and a reflecting mirror.

In this document, it is intended to place the image generating unit and the reflecting mirror in a protective overall housing which includes an image output window adapted to pass the images sent by the reflecting mirror to the combiner. This exit window is closed by a protective film, formed of a transparent acrylic resin, so that the image projection device is enclosed in a closed enclosure.

In addition, to prevent the external light from degrading the images generated by the generation unit, there is provided a shading wall placed in the overall protective housing, between said exit window of the protective housing and the unit. of image generation.

However, this shading wall only partially prevents the external light from degrading the images generated by the projection device.

Furthermore, the assembly is complex because it requires the independent attachment in the overall protective housing, the LCD screen, light sources, the reflecting mirror, and the protective film. And besides, in the proposed assembly, the sealing at the exit window is imperfect. Finally, the protective film is directly accessible to the driver, it can be easily damaged, for example scratched or stained.

OBJECT OF THE INVENTION

In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes to provide a protection duct connecting the image generation unit and the image return unit, on which an exit window is provided. images to the combiner.

It is also planned to close this exit window by a protective film so that said protective film is lowered relative to the dashboard of the vehicle.

More particularly, there is provided according to the invention a device for projection of images as described in the introduction, which further comprises a protection conduit connecting said generation and image return units and comprising an output window of the returned images, and wherein said output window is closed by a at least partially transparent protective film.

Other non-limiting and advantageous features of the image projection device according to the invention are the following:

said protective film is an optical filter and has a curved shape whose concavity is turned towards the outside of said duct;

said protective duct comprises a first piece and a second piece in which is provided said image exit window closed by the protective film;

said protective duct comprises means of attachment to said image generation unit and means of attachment to said image return unit;

- said protective conduit is rigid material.

The invention finds a particularly advantageous application in a head-up display comprising such an image projection device and in which the image generation unit is adapted to send the generated images to the image return unit, through the protection duct, and the image return unit is adapted to return the generated images to a combiner, through said output window of the protection duct.

The invention also proposes a method of manufacturing such an image projection device for a head-up display, according to which:

a) a transparent protective film is fixed on an image output window of a protective conduit, and

b) assembling said protective conduit on one side to an image generating unit of said image projection device, and the other to an image returning unit of said image projection device.

The method of manufacture described may further optionally have the following advantageous characteristics:

in step a), the protection duct comprising a first part and a second part comprising said image output window, the protective film is fixed on said second part; in step a), the fixing of the protective film on the outlet window of the duct is performed by ultrasonic welding;

in step b), the units for generating and returning images are fixed on the same support piece;

in a step subsequent to step b), the support piece, on which the image generation and return units connected by the protective duct are fixed, is fixed in a protective housing of said projection device.

DETAILED DESCRIPTION OF AN EXEMPLARY EMBODIMENT The following description with reference to the accompanying drawings, given by way of non-limiting examples, will make it clear what the invention consists of and how it can be implemented.

In the accompanying drawings:

- Figure 1 is a schematic representation of principle of a head-up display according to the invention in position in a vehicle;

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

- Figure 3 is a schematic sectional view of the head-up display of Figure 2 assembled;

FIG. 4 is a side view of an image projection device according to the invention used in the head-up display of FIG. 2;

FIG. 5 is an exploded three-quarter view of a portion of the image projection device of FIG. 4;

FIG. 6 is a rear perspective view of a first embodiment of a support piece according to the invention for the image projection device of FIG. 4;

FIG. 7 is a front perspective view of a second embodiment of a support piece according to the invention; and

- Figure 8 is another rear perspective view of the support part of Figure 7 carrying an image projection device according to the invention.

In the remainder of the description, the terms "front" and "rear" will be used to designate the elements in position in the motor vehicle, with respect to the longitudinal direction of said motor vehicle. The front will designate the side of an element facing the driver, ie the side facing the chest, and the rear will point to the side of this element facing the hood.

In the same way, the terms "lower" and "upper" will be used to designate the elements in position in the motor vehicle, with respect to the vertical direction of said motor vehicle. The lower part of an element shall be the part of that element which is located on the side of the floor of the vehicle and the upper part shall be the part of that element which is situated on the side of the roof.

In Figure 1, there is shown the main elements of a head-up display 1 for equipping a vehicle, for example a motor vehicle.

Such a display 1 is adapted to create a virtual image I in the field of vision of a driver of the vehicle, so that the driver can see this virtual image I and any information it contains without having to look away.

For this purpose, the display 1 comprises a combiner 10 placed in the field of view of the driver (see FIG. 1), and an image projection device 20 adapted to generate an image and to send it towards said combiner 10 .

More precisely, the image projection device comprises an image generation unit 22 adapted to generate images and an image return unit 24 adapted to receive the images of the generation unit 22 and to send them back to the images. direction of the combiner 10.

FIGS. 4 and 5 show more precisely the image projection device 20 of the head-up display 1.

As shown in FIG. 4, the deflection unit 24 of the projection device 20 comprises a folding mirror 240. Here, the folding mirror 240 is a plane mirror.

The deflection unit 24 also comprises a fixing support 241 of said folding mirror 240. This fixing support 241 is provided with flexible clamping tabs 241 A and claws 241 B adapted to retain on said fixing support 241 the mirror of refolding 240.

The fixing support 241 further comprises latching tabs 241 C provided for fixing said fixing support 241 to a conduit 40 for protecting the deflection unit 24.

The fixing support 241 finally comprises other latching lugs (not visible in the drawings) intended to fix said fixing support 241 in the projection device 20.

In a variant, the unit for returning the generated images could comprise a plurality of mirrors and / or other optical elements.

As can be seen in FIG. 5, the generation unit 22 of the projection device 20 here comprises a screen 220 backlit by a backlight module 222.

The screen 220 is a liquid crystal display (or LCD for liquid crystal display), for example thin film transistors (or TFT for "Thin-Film Transistor").

The backlight module 222 comprises a set of light sources 221 mounted on a support 223, and a reflector 224 associated with a diffuser 225. The diffuser 225 is here placed on the front end of the reflector 224, and the support 223 of the sources light 221 is placed on the rear end of the reflector 224 so that the assembly composed of the support 223, the reflector 224, and the diffuser 225 forms a closed enclosure.

The light sources 221 are light emitting diodes (or LEDs) mounted on a printed circuit serving as support 223.

These light sources 221 are here arranged in a single row of a plurality of light sources 221 here comprising seven light sources 221. Alternatively, they could include a different number, for example a number between 2 and 10.

The support 223 comprises centering means C1 of the reflector 224 on said support 223. Here, these centering means C1 are circular holes adapted to receive centering pins, such as rivets or bolts provided with their nut.

The reflector 224 can be seen as an optical box whose walls are illuminated on their inner face by all the light sources 221. The reflector 224 is adapted to reflect the light optimally so that the brightness is homogeneous at the diffuser 225.

The reflector 224 also comprises centering means C2 on the support 223 in the form of circular holes adapted to correspond with the centering means C1 of the support 223.

The reflector 224 further comprises snap tabs 224A provided for fixing said reflector 224 in the image projection device.

The diffuser 225 can be made by means of a film having a smooth face facing the light sources 221 and an opposite grainy face, facing the screen 220, which produces light scattering.

The screen 220 is placed in contact with the diffuser 225, with its extension plane parallel to that of said diffuser 225.

A cover 226 is placed over the screen 220 so as to cover the edges of said screen 220. Thus, the screen 220 and the diffuser 225 are sandwiched between the cover 226 and the reflector 224.

Alternatively, the image generation unit could include a diffuser and a scanning unit that would generate a variable direction light beam for scanning one of the faces of said diffuser.

The scanning unit would then comprise a module for forming a light beam, for example formed of three monochromatic light sources, and a mobile mirror for example made in the form of an electromechanical microsystem (or MEMS for "MicroElectroMechanical System") .

Furthermore, here, the image generation unit 22 is controlled by a printed circuit 26, electrically connected to said generation unit 22 by a connector 27 (see FIG. 4).

The printed circuit board 26 includes power supply circuits for the screen 220 of the image generation unit 22 and the control circuits of the same screen 220, and the printed circuit 26 is therefore directly connected to the screen 220.

Advantageously, the already mentioned protective conduit 40 connects said image generating and returning units 22, 24 with each other (see FIG. 2).

This protection duct 40 forms a tunnel, one wall of which is recessed, so as to connect the screen 220 and the folding mirror 240 on the one hand, and to release the images towards the combiner 10 on the other hand.

More specifically, when the duct 40 is in position in the projection device 20, a rear opening 40A of the duct 40 is contiguous with the screen 220, a front opening 40B of the duct 40 is contiguous with the folding mirror 240, and a 40C exit window is provided on an upper side said duct 40 to let the images out to the combiner 10.

In other words, in the head-up display 1, the generation unit 22 of the images is adapted to send the images generated to the image return unit 24, through the protection channel 40, and the return unit. 24 images is adapted to return the generated images to the combiner 10, through said output window 40C of the conduit 40 protection.

As shown in FIG. 2, the duct 40 comprises two main parts: a first image entry piece 41 and a second output piece 42 of said images.

More specifically, the first part 41 has a generally elongated trapezoidal shape, which comprises four solid side walls whose rear free edges form said rear opening 40A of the duct 40, and whose free edges before form an intermediate opening 41 A located opposite said rear opening 40A. The rear opening 40A delimits a plane generally perpendicular to a longitudinal axis of the trapezoidal volume, and the intermediate opening 41 A defines an oblique plane with respect to said longitudinal axis.

The first piece 41 of the duct 40 comprises, at the rear opening 40A, connecting means to the screen 220, and, at the intermediate opening 41A, connecting means to the second piece 42 of the leads 40.

The joining means of the first piece 41 to the second piece 42 are returns which extend over the entire contour of the intermediate opening 41 A to form a continuous rim.

The joining means of the first part 41 on the screen 220 are also returns which form a flat flange over the entire contour of the rear opening 40A. The planar rim is designed to be joined with the cache 226 of the image generation unit 22.

These connecting means may constitute means for fixing the conduit 40 to the image generation unit 22.

The second piece 42 also has a generally trapezoidal shape which comprises four side walls, three adjacent are full. The rear free edges of these four side walls form said front opening 40B of the duct 40, and the rear free edges of said side walls form another intermediate opening 42A facing the front opening 40B. The intermediate opening 42A of the second piece 42 defines an oblique plane corresponding perfectly with the oblique plane of the intermediate opening 41A of the first piece 41, so that the first and second pieces 41, 42 are perfectly contiguous at their level. intermediate openings 41A, 42A.

The opening 40B before the duct 40 delimits a plane adapted to merge with the plane of the folding mirror 240 when the projection device 20 is assembled.

One of the side walls of the second piece 42 is partially recessed so as to form the exit window 40C of said duct 40.

Here, the exit window 40C of said duct 40 is located on the upper wall of said second piece 42.

The outlet window 40C of the duct 40 delimits a curved surface whose concavity is turned towards the outside, and which is generally directed towards the rear of said duct 40.

The second part 42 comprises, at its intermediate opening 42A, connecting means to the first part 41, and, at the level of said front opening 40B of the duct 40, fixing means to the folding mirror 240.

The joining means of the second piece 42 to the first piece 41 are returns that extend over the entire contour of the intermediate opening 42A to form a continuous rim designed to be joined to the continuous rim of the first piece 41.

The fastening means of the second piece 42 to the folding mirror 240 are notches for receiving clips provided for this purpose in the fixing bracket 241 of the image transfer unit 24.

These fixing means constitute means for fixing the conduit 40 to the image return unit 24.

Advantageously, the exit window 40C of the duct 40 is closed by a protective film 43.

Thus, in position in the projection device 20, the duct 40 forms a closed enclosure, closed on the rear side by the screen 220, on the front side by the folding mirror 240 and finally by the protective film 43 at the window 40C output. This duct 40 is thus adapted to protect the optical elements of the generating and returning units 22, 24 of images of dust and moisture.

Furthermore, advantageously, the protective film 43 is adapted to be assembled to the duct 40 by ultrasonic welding on the edges of the outlet window 40C, so that the protective film 43 is perfectly joined to the duct 40.

To do this, the material used to make the duct 40 is rigid, so that the protective film 43 can be positioned correctly on the duct 40 before the ultrasonic welding.

Advantageously, the protective film 43 is at least partially transparent, that is to say adapted to allow the images reflected by the folding mirror 240 to pass to the combiner 10.

In addition, the protective film 43 is adapted to reflect the light rays outside the duct 40.

More specifically, the shape of the surface of the protective film 43 makes it suitable for reflecting the radii outside the duct 40.

For example, the protective film 43 has a curved shape whose concavity is turned towards the outside of said duct 40. This makes it possible to limit the amount of parasitic light coming from the sun.

The protective film 43 may also be an optical filter. For example, the optical filter may be a polarizer filter for blocking a portion of the light from the sun.

Alternatively, it is conceivable that the protective film is coated with antireflection treatment on its outer face, that is to say on its side facing the outside of the conduit.

In addition, the duct 40 is advantageously made of an opaque material, which makes it possible to isolate the generating and returning units 22, 24 of images of the light sources external to said units. Thus, the images sent to the combiner 10 have a more intense brightness and their sharpness is improved.

Furthermore, as it appears in FIG. 4, the image projection device 20 comprises a support piece 25 which carries the generation and return units 22, 24 of the images.

Advantageously, said image generation and return units 22, 24 being carried by the same support part 25, they are oriented one by one. relative to each other optimally on this support piece 25.

In other words, the screen 220 and the folding mirror 240, by their sole attachment to the support piece 25, are inclined relative to each other ideally to create quality images and to reflect them to the O combinator.

FIGS. 5 and 6 show a first embodiment of said support piece 25, and FIGS. 7 and 8 show a second embodiment of said support piece 25.

Remarkably, whatever the embodiment envisaged, the support piece 25 comprises support means 252 of said image generation unit 22 and support means 254 of said return unit 24 of said generated images (see FIG. Figures 5 and 6).

More specifically, the support part 25 comprises two lateral uprights 251 mirrored with respect to each other, and a transverse upright 253 connecting said lateral uprights 251.

The lateral uprights 253 each have a "Y" shape and comprise a lower leg 251 A, a front arm 251 B and a rear arm 251 C.

Thus, the rear end of the rear arm 251 C extends backwards relative to the rear end of the leg 251 A, and the front end of the front arm 251 B extends forward with respect to the front end. foot 251 A.

In addition, the upper rear end of the rear arm 251 C extends in a region generally lower than the region in which extends the upper front end of the front arm 251 B.

The lateral uprights 251 are connected to each other at the rear end of their rear arm 251 C, by the transverse upright 253. In other words, the transverse upright 253 and the lateral uprights 251 the support part 25 are arranged to form a "U".

The cross member 253 includes said support means 252 of the image generation unit 22 of the image projection device.

These support means 252 are here four rectangular slots 252A adapted to receive the latching lugs 224A of the reflector 224 of the backlight module 222 (see Figure 6).

The transverse upright 253 further comprises centering means C3 of the generating unit 22, which here are two circular holes adapted to correspond with the centering means C1, C2 of the support 223 and the reflector 224 of said image generation unit 22.

Thus, the centering means C1, C2, C3 being in correspondence with each other, it is possible to insert centering pins, such as rods, so that the support 223 and the reflector 224 are aligned when the assembly of the generation unit 22 on the support part 25.

As shown in FIG. 5, in position in the image projection device, the support 223 of the light sources 221 of the backlight module 222 is sandwiched between the reflector 224 and the transverse post 253, the reflector 224. further supporting the diffuser 225 and the screen 220, so that the support member 25 carries the image generation unit 22 as a whole.

The image generation unit 22 is then carried by the transverse upright 253, and housed between the lateral uprights 251 of the support part 25.

On the other hand, the front arm 251 B of each lateral upright 251 comprises a support means 254 of the return unit 24 of the generated images.

More specifically, the front arm 251 B of each lateral upright 251 comprises, at its front end, a tab 254A (see Figure 5) which extends over the entire height of said front arm 251 B.

These tabs 254A may for example be obtained by folding the front end of the front arm 251 B, about an axis oblique to the vertical axis, to the lateral upright 251 facing.

The tabs 254A extend in the same plane orthogonal to the respective planes in which the lateral uprights 251 extend, and at an angle to the plane in which the transverse upright 253 extends, so that the intersection of said extension plane of the transverse upright 253 and said extension plane of the tabs 254A forms an acute angle

Each tab 254A is provided with a rectangular slot 254B adapted to receive one of the latching tabs 241 C of the attachment support 241 of the image return unit 24.

Each lug 254A further comprises a circular hole 254C provided to secure the fixing of the folding mirror 240 on the support piece 25. These holes 254C adapted to receive rivets or bolts on which one screws a nut, so as to prevent the folding mirror 240 from detaching from the support member 25 during any jolts undergone when the vehicle is in operation.

The tabs 254A, the slots 254B, and the holes 254C thus form the support means 254 of the image return unit 24.

In addition, the support piece 25 is adapted to carry the printed circuit 26 of power supply and / or control of the generation unit 22 images.

For this purpose, the support member 25 comprises support means for said printed circuit board 26.

Preferably, said control circuit board 26 is carried in a lower region of the support part 25, with respect to the regions in which the image generating and returning units 22, 24 are carried.

Here, the printed circuit 26 is carried by the feet 251 A of the lateral uprights 251 of the support part 25.

According to the first embodiment of the support piece, the support means (256, 256A) are located at the front of the support piece 25.

More specifically, the support means of the printed circuit 26 are located on the front end of the foot 251 A of each lateral upright 251.

These support means are here four tabs 256, each being provided with a circular fixing hole 256A (see FIGS. 4 and 5) adapted to receive a fixing means of the printed circuit board 26, such as a bolt provided with a nut. or a rivet.

The tabs 256 are for example obtained by folding the front portions of the foot 251 A of each lateral upright 251, about a generally vertical axis, to the side jamb 251 mirror.

According to the second embodiment of the support piece 25, the support means (27) are located at the rear of the support piece.

More specifically, the connector 27 carries the printed circuit 26 and forms the support means of said printed circuit (see Figure 8).

Advantageously, the support piece 25 also makes it possible to correctly hold the connector 27 connecting the screen 220 and the printed circuit 26 for controlling said screen 220.

Advantageously, the support piece 25 is adapted to support the cable connecting the printed circuit board 26 and the printed circuit forming the support 223 of light sources 221.

Furthermore, the support piece 25 is made of a rigid material so as to support without bending the various elements of the image projection device 20.

Here, advantageously, it is made of metallic material. Thus, it is adapted to dissipate the thermal energy created at the light sources 221 of the backlight module 222 of the image generation unit 22.

To facilitate said dissipation of thermal energy, the support piece 25 may further comprise a heat dissipation means. Here, the heat dissipation means is a metal radiator 28 fixed on a return 255 of the transverse upright 253. By way of non-limiting example, the radiator 28 is a folded strip.

Advantageously, the support member 25 carrying the image generation unit 22, the return unit 24 of said images, and the printed circuit 26, makes the image projection device 20 particularly compact.

Here, the support piece 25 measures less than 15 centimeters (cm) along the vertical axis, less than 15 cm along the longitudinal axis and less than 15 cm along the lateral axis.

In the exemplary embodiment of the head-up display 1 described, the combiner 10 is a semi-transparent plate 10.

It is here placed between the windshield 2 of the vehicle and the eyes of the driver.

Furthermore, advantageously, the semi-transparent plate 10 is here retractable in a protective housing 30 of said image projection device 20 (see FIG. 3).

More specifically, the semi-transparent blade 10 can adopt two distinct positions: an extended position in which it protrudes relative to an upper portion of said protective housing 30, and a retracted position in which it is housed in a lower part protective housing 30.

More precisely, in the retracted position, it is placed between an inner wall of said protective housing 30 and said support part 25.

Thus, in the retracted position, the semi-transparent plate 10 is integrally housed in the protective housing 30, preferably in a rear region of said protective housing 30.

In order to easily move from the retracted position to the deployed position, the semi-transparent plate 10 is mounted on displacement means January 1.

Alternatively, it could be provided that the windshield of the vehicle plays the role of combiner so that the semi-transparent blade could be omitted (as well as the moving means 1 1).

The protective housing 30 (see FIGS. 2 and 3) is adapted to house the projection device 20.

This protective housing 30 is here integrated into the dashboard of the vehicle.

It comprises (see FIG. 2) a lower part which forms a box 31, and an upper part which forms a lid 32.

Here, the box 31 comprises a bottom 31 A from which rises a side wall 31 B which opens on an opening. This opening is adapted to receive by fitting the cover 32, so as to close the box 31.

Advantageously, the support piece 25 supports all the elements of the projection device 20, which facilitates the mounting of said image projection device in the protective housing 30.

Indeed, only the support piece 25 needs to be fixed in the protective housing 30.

For this purpose, the support part 25 comprises fixing means 260; 270 to protective housing 30.

According to the first embodiment of the support member 25, there is provided lower fixing means 260, so that the support piece is adapted to be fixed in the bottom 31A of the box 31.

More precisely, the fastening means 260 are here two horizontal tabs 260A (see FIG. 5) provided on the lateral uprights 251 of the support piece 25, and adapted to be fixed in the bottom of said protective housing 30.

These horizontal tabs 260A are for example obtained by folding a lower portion of the foot 251 A of each lateral upright 251, about a longitudinal axis, to the side jamb 251 mirror.

In addition, each horizontal leg 260A here comprises a hole 260B circular ring adapted to receive a fixing means, such as a bolt provided with a nut or a rivet, so as to secure said support member 25 to the protective housing 30.

According to the first embodiment, each horizontal tab 260A is also provided with a pin 260C adapted to be introduced into a notch provided on a lower edge of the printed circuit 26. This pin 260C partially retains the printed circuit board 26 so that the mass of said printed circuit 26 is not fully supported by the support means 256 of said printed circuit 26.

As a variant of this first embodiment, provision could be made for the fastening means to be horizontal lugs provided with a bead protruding from their lower face. This bead would be adapted to be clipped into force in a notch provided for this purpose on an inner face of the bottom of the housing of the protective housing.

According to the second embodiment of the support member 25, there is provided fastening means 270 before, so that said support piece 25 is adapted to be fixed on the side wall 31 B before the box 31.

More specifically, the fastening means 270 are here two vertical tabs 270A adapted to slide in a slideway provided inside the side wall 31B before the box 31 of said protective housing 30 (see Figure 7).

The vertical tabs 270A are here provided at the front of the foot 251A of each lateral upright 251 of the support piece 25.

They are for example obtained by folding the front portions of said foot 251 A of each lateral upright 251 around a generally vertical axis, towards the side jamb 251 in a mirror.

Moreover, whatever the embodiment envisaged, the support piece 25 is adapted to keep the image generation unit 22 away from the walls 31 A, 31 B, 32 of the protective housing 30 of the projection device 20 images.

In other words, the image generation unit 22 is not in direct contact with the bottom 31A, or the side wall 31B of the box 31, or the cover 32 of the protective housing 30.

Whatever the envisaged embodiment of the support piece 25, this is fixed in a front region of the protective housing 30 so that space is released in a rear region of said protective housing 30.

Furthermore, the cover 32 of the protective housing 30 comprises a first opening 34 adapted to allow the images sent by the image return unit 24 to pass to the combiner 10, and a second opening 36 adapted to allow the semiconductor blade to pass through. transparent 10 so that it protrudes from the upper face of the lid 32.

The protective housing 30 further comprises a cover 33 attached to a portion of the second opening 36 of the cover 32 (Figure 2) so that when the semi-transparent blade 10 is in the deployed position, the second opening 36 of the protective housing 30 is completely obstructed, and when the semi-transparent blade 10 is in the retracted position, only part of the second opening 36 is open to the outside.

On the other hand, the protective housing 30 is here made of a rigid and opaque plastic material.

Thus, advantageously, the protective housing 30 makes it possible to protect and hide the optical elements of the image projection device 20. It also allows the image projection device to be confined to isolate it from any source of stray light that could impair its proper operation.

In the following part is presented an example of a method of manufacturing a projection device 20 for head-up display 1 as described above.

According to this manufacturing process:

a) the transparent protective film 43 is fixed on the image exit window 40C of the protective conduit 40,

b) assembling said protective conduit 40 on one side to the image generation unit 22 of said image projection device, and on the other side to the image rejection unit 24 of said imaging device. 20 images projection.

In step a), the fixing of the protective film 43 on the exit window 40C of the duct 40 is made by ultrasonic welding.

Thus, advantageously, the protective film is fixed in a perfectly contiguous manner to the duct 40.

Alternatively, one could consider sticking the protective film on the edges of the outlet window of the conduit. Here, the protective film 43 is more precisely welded to the second main part 42 of the duct 40, at the outlet window 40C of said duct 40.

This attachment is facilitated because it is performed on said second piece 42 of the duct 40 which is relatively small and manageable.

Said second piece 42, provided with the protective film 43, is then assembled to the first piece 41 to form said duct 40.

Here, the first and second pieces 41, 42 of the duct 40 are assembled at their respective intermediate apertures 41A, 42A.

This assembly is for example made by ultrasonic welding. Alternatively, this assembly can be achieved by riveting together the edges of the intermediate openings of the first and second parts.

Furthermore, it is considered that the image generation unit 22 and the image return unit 24 have been fabricated in a step prior to step b) of the method.

According to a first variant of the manufacturing method, it is considered that the generating and returning units 22, 24 of images are set independently in the image projection device.

According to this variant, in step b), the deflection unit 24 being pre-fabricated, it is considered that the folding mirror 240 is already fixed on the fixing support 241.

The reflective face of the folding mirror 240 is then placed opposite the front opening 40B of the duct 40 assembled and provided with the protective film 43.

Said duct 40 is then fixed on the rear face of said fixing support 241 of the image return unit 24.

Since the image generation unit 22 is also pre-manufactured, it is considered that this generation unit 22 is fixed in the image projection device.

The screen 220 of the image generation unit 22 is then placed in front of the rear opening 40A of the duct 40, said duct 40 being assembled, provided with the protective film 43, and already attached to the return unit. 24.

Said duct 40 is then fixed against said image generation unit 22 by any fixing means.

The image return unit 24 is thus indirectly fixed on the image generation unit 22, by means of the protection channel 40. According to a second preferred variant of the method, in step b), the image generation and return units 22, 24 are fixed on the support piece 25.

According to this second variant, whatever the embodiment of the support piece 25, it is manufactured in one piece, by folding and cutting a sufficiently rigid metal plate.

The generation unit 22 is first fixed on the support piece 25.

To do this, centering pins are placed in the holes C3 of the transverse upright 253 of the support part 25, and the holes C1 of the support 223 of the light sources 221 are also placed on these centering pins. The holes C2 of the reflector 224 are also placed on these centering pins and the reflector 224 is then clipped into the notches 252A of the transverse upright 253 of the support part 25.

Furthermore, the duct 40, assembled and provided with the protective film 43 following step a) of the method, is fixed to the return unit 24 of the images.

To do this, said duct 40 is clipped on the rear face of the attachment support 241 of the image return unit 24.

Then, the imaging unit 24 is fixed on the support part 25.

For this purpose, the fixing support 241 of the image deflection unit 24 is fixed on the support part 25.

More specifically, the other latching lugs (not visible in the figures) are inserted in the slots 254B provided for this purpose on the support part 25.

Thus, the duct 40 is fixed, on one side, to the image transfer unit 24, and is held in force, on the other side, against the cache 226 of the image generation unit 22. , so that it forms a closed enclosure.

The operator also fixes the printed circuit 26 on the support part 25.

The operator then plans to wire the electronic elements together. For example, it connects the circuit board 26 and the screen 220 with the connector 27.

In a step subsequent to step b), the support piece 25, on which are fixed the generating and returning units 22, 24 of connected images. by the conduit 40 of protection, is fixed in the protective housing 30 of said projection device 20.

Depending on the embodiment of the support member 25, this attachment can be done by inserting the vertical tabs 270A of the support member 25 in the rails provided in the side wall 31 B of the box 31 of the protective housing 30, or by fixing the horizontal tabs 260A in the bottom 31 A of the box 31 of the protective housing 30.

Thus, thanks to the support part 25, the assembly of the projection device 20 and its attachment in the protective housing 30 are facilitated.

Claims

1. An image projection device (20) for a head-up display (1) comprising:

a generation unit (22) of images, and

a unit for returning (24) the images generated,

characterized in that it further comprises a protection conduit (40) connecting said image generating and returning units (22, 24) and including an output window (40C) of the returned images,

and in that said exit window (40C) is closed by an at least partially transparent protective film (43).

The projection device (20) of claim 1, wherein said protective film (43) is an optical filter and has a curved shape whose concavity faces outwardly of said conduit (40).

3. Projection device (20) according to one of claims 1 and 2, wherein said conduit (40) of protection comprises a first part (41) and a second part (42) in which is provided said output window ( 40C) images closed by the protective film (43).

4. Projection device (20) according to one of claims 1 to 3, wherein said conduit (40) of protection comprises fixing means to said generating unit (22) of images and fixing means to said unit for returning (24) images.

5. Projection device (20) according to one of claims 1 to 4, wherein said conduit (40) of protection is rigid material.

Head-up display (1) comprising a projection device (20) of images according to one of claims 1 to 5, wherein:

the generation unit (22) of the images is adapted to send the images generated to the image return unit (24), through the protection duct (40), and

- The image return unit (24) is adapted to return the generated images to a combiner (10), through said output window (40C) of the protection conduit (40).

7. A method of manufacturing an image projection device (20) for head-up display (1), according to which:

a) a transparent protective film (43) is fixed on an output window (40C) of images of a protective conduit (40), and

b) assembling said protective conduit (40) on one side to an image generating unit (22) of said image projection device (20) and on the other to a return unit (24). images of said image projection device (20).

8. The manufacturing method according to claim 7, wherein in step a), the conduit (40) of protection comprising a first part (41) and a second part (42) comprising said output window (40C). images, the protective film (43) is fixed on said second piece (42).

9. The manufacturing method according to one of claims 7 and 8, wherein, in step a), the fixing of the protective film (43) on the outlet window (40C) of the duct (40) is made by welding ultrasound.

10. Method according to one of claims 7 to 9 wherein, in step b), the generating units and returning (22, 24) of images are fixed on the same support member (25).

1 1. A method according to claim 10 wherein, in a step subsequent to step b), the support piece (25), on which are fixed the generating units and returning (22, 24) images connected by the conduit (40) is fixed in a protective housing (30) of said projection device (20).