EP2954366A1

EP2954366A1 - Image transmission device for a display and head-up display equipped with said device

Info

Publication number: EP2954366A1
Application number: EP13818256.3A
Authority: EP
Inventors: Richard GELOEN
Original assignee: Valeo Etudes Electroniques SAS
Current assignee: Valeo Comfort and Driving Assistance SAS
Priority date: 2012-12-28
Filing date: 2013-12-10
Publication date: 2015-12-16
Also published as: FR3000572A1; FR3000572B1; CN105308493A; JP2016505164A; US9733476B2; US20150355460A1; WO2014102463A1

Abstract

The invention relates to an image transmission device for a display intended to display a virtual image in a driver's field of view, said transmission device comprising: a semi-reflective optical element (21) configured to transmit light rays that can be used to display the virtual image in the field of view, said optical element (21) also being configured to guide the light; and a light source (30) emitting a light beam, said light source (30) and said optical element (21) being positioned in relation to one another such that the beam is emitted by the optical element (21) operating as a light guide.

Description

IMAGE TRANSMISSION DEVICE FOR DISPLAY AND HIGH TEAM DISPLAY EQUIPPED WITH SAID DEVICE

The invention relates to a display image transmission device for displaying in the field of view of a driver a virtual image and a display equipped with said device.

It is known motor vehicles comprising a display device, said head-up display, for displaying in the field of vision of the driver of a virtual image comprising information relating to the state of the motor vehicle, traffic or other.

It in particular known head-up displays comprising semi-reflective blades for forming the virtual image, said semi-reflective blades being configured to stand above a dashboard of the vehicle. We seek today to make said blades as discrete as possible.

The invention counteracts this trend and proposes a display image transmission device intended to display a virtual image in the field of view of a driver, said transmission device comprising:

a semi-reflective optical element, configured to transmit light rays for displaying said virtual image in said field of vision, said optical element being further configured to guide the light,

a light source, emitting a light beam,

said light source and said optical element being located relative to each other so that said beam is emitted by said optical element operating as a light guide.

In this way, said optical element is enriched with a complementary function that can be used to perform redundancies or to highlight alerts. According to various embodiments of the invention that can be taken together or separately:

said light source comprises at least one light emitting diode,

said optical element is a blade, in particular a semireflecting blade,

said blade comprises two faces transmitting said rays, said faces being connected by a slice,

said slice comprises a first portion forming an entrance face of the light beam,

said slice comprises a second portion forming the exit face of the light beam,

said slice is beveled at said exit face,

said input face is configured to face a vehicle dashboard,

said input face corresponds to one of the sides of a contour of said blade and said output face corresponds to the other sides of said contour,

said light source comprises a plurality of light-emitting diodes arranged along said input face,

said diodes are of different colors,

said device comprises a flexible conductor for feeding said diodes,

said diodes are disposed on said flexible conductor.

The invention also relates to a display comprising an image transmission device as described above.

Said display may include means for activating the light source.

According to one aspect of the invention, said activation means are configured to operate alternately said light source, in particular in the manner of a blinker.

Said display may also include means for controlling an image generating device of said display, said control means being configured to drive said activation means. Said image generation device comprises, for example, a light source provided with one or more laser diodes. These features and advantages of the invention and others will emerge more clearly from the following description of embodiments of the invention with reference to the accompanying drawings, in which:

Figure 1 is a schematic elevational view of a vehicle image display according to the invention;

FIG. 2 is a schematic representation, in perspective, of an exemplary embodiment of a transmission device equipping a display such as that of FIG. 1.

In the following description, identical references are used to designate similar or identical elements.

As illustrated in FIG. 1, the invention relates to a display 1, also called head-up display, for displaying a virtual image 9 in the field of view of a vehicle driver 5 observing a trajectory of movement of the motor vehicle.

The display 1 comprises an image generation device 1 1. Said device comprises, for example, a scanning projector 34 provided with one or more light sources each emitting a beam of the laser type. This is, for example, laser sources, typically laser diodes, each source laser emitting a monochromatic beam, that is to say consisting of a single color.

Said device may typically comprise three sources, said device being configured to form a light beam by pooling by combining the beams individually emitted by each of said sources. Specifically, it may be sources emitting a beam of a different color from one source to another. Colors are, for example, red, green, or blue (RGB).

The optical power of each of the sources is controlled, independently, using the power supply of the laser source or sources. At a given optical power, the color of the light beam is determined by the way in which a power ratio is established between the different laser diodes. For example, to obtain a white light, the optical powers, in proportion, must be established according to the following distribution: 60 for the green diode, 30 for the blue diode, 10 for the red diode. The optical power of each of the sources can also be controlled to modulate the optical power of the light beam.

The beams emitted by each of the sources are oriented, for example, parallel to each other and reflects in the same direction to form by combination a common light beam. Said device comprises in this sense semi-transparent optical elements, over a range of wavelengths, such as dichroic mirrors or combination blades, intercepting the beams emitted by each of said sources and combining them according to the direction of said beam.

More generally, said device is configured to form said light beam from said laser beam or beams, regardless of the number of sources involved. In the case of a single source, the light beam is composed of the laser beam emitted by the only source used and the image obtained will then be monochrome, composed of different levels of optical powers applied to each of the points that compose it, according to a gradient of said color. In the case of a plurality of sources, typically the three sources mentioned above, said common beam which then forms said light beam will allow the establishment of an image according to a color spectrum whose resolution will correspond to the fineness of control of the power supply. said sources.

Said device may further comprise means for controlling the power supply of said sources. As mentioned above, they may allow a choice of the color of the light beam.

Said scanning projector further comprises, for example, a scanning generator whose function is to move horizontally and vertically the light beam emitted by the light source (s) in order to perform a scanning according to a frequency, in particular equal to 60 Hz, as a non-limiting example. The scanning generator comprises, in particular, a scanning mirror with a micro-electro-mechanical system (hereinafter referred to as the MEMS mirror) on which the light beam emitted by the light source (s) is reflected in a scanning beam (10). MEMS mirror has for example a diameter of 1 mm ² . The MEMS mirror is able to rotate about two axes of rotation to perform a scan, for example at the refresh rate of 60 Hz, a diffuser screen 29 of said device. Said image is then formed on said diffuser 29. Alternatively, the MEMS mirror can be replaced by two plane and movable mirrors, whose movements are associated. One of these mirrors can be dedicated to a scan along a horizontal axis while the other mirror can be dedicated to a scan along a vertical axis.

The diffuser 29 where the image is formed may be a transparent projection screen with a complex structure for projection by transparency. It can alternatively be translucent. It is made, for example, of glass, especially frosted, or polycarbonate. By way of example, the diffuser screen 29 is of the exit pupil type ("Exit Pupil Expander"). It allows to have a cone expanded observation. It extends in a plane traversed by the light beam, the resulting image of this scanning beam 10 being formed in the plane of a face of the diffuser screen 29. This diffuser screen receives the scanning beam 10. It is arranged to cause a dispersion of this scanning beam 10 in an angular sector, for example, equal to 30 ° with respect to the direction of the scanning beam 10 when it strikes the diffuser screen 29. To do this, according to a non-limiting example, a face of the diffuser screen is rough, in that it has asperities that cause the dispersion of the scanning beam. The rough face corresponds to that by which the beam emerges, that is to say the face on which the image is formed.

Downstream of the diffuser screen 29 depending on the direction of movement of the light beam, said display comprises at least one semi-reflecting optical element 21 and, optionally, a reflection device 25 interposed on the path of the image between the diffuser screen 29 and said semi-reflective optical element 21. In this figure, the path of the image is symbolized by arrows which are reflected on the reflection device 25 before being displayed through said semi-reflecting optical element 21. the latter may allow a magnification and / or, by transparency, a display of the image 9 beyond said semi-reflective optical element 21, in particular beyond the windshield of the equipped vehicle, at a virtual screen, obtained using said semi-reflective optical element 21.

This semi-reflective optical element 21 is advantageously transparent and has a reflectivity of at least 20%, which allows the user to see through said transmission device the route taken by the vehicle, while benefiting from a high contrast to see the image displayed.

However, as illustrated in Figure 2, the invention also relates to a image transmission device comprising a semi-reflecting optical element 21 as mentioned above, namely an optical element 21 configured to transmit the light rays for displaying said virtual image in said field of view of the driver. According to the invention, said optical element 21 is further configured to guide the light.

Said transmission device further comprises a light source, 30, emitting a light beam. Said light source 30 and said optical element 21 are further located relative to each other so that said beam is emitted by said optical element 21, operating as a light guide. In other words, the light emitted by said light source 30 is guided by said optical element and is perceived by the observer, in particular the conductor, through said optical element 21. Said optical element 21 is, for example, a blade, in particular semi-reflective. Said blade may comprise two faces 32, 34 transmitting the rays forming the virtual image 9, said faces being connected by a wafer 36. Said wafer 36 comprises a first part forming the input face 38 of the light beam emitted by said light source 30 of said transmission device. Said slice 36 further comprises a second portion forming an exit face 40 of said light beam. In other words, here, said optical element 21 emits light from said light source 30 at said output face 40. The driver thus has, in addition to the information contained in said virtual image 9, a light the semi-reflecting blade edge 21.

For example, said lighting may be intended to attract the driver's attention to a danger, this by choosing an appropriate color, especially red. Other examples of coloration are of course possible.

Said slice 36 may be frosted, especially by graining, this in particular at said outlet face 40. It presents advantageously a beveled section to be made more visible to the driver.

Said input face 38 is here configured to face a dashboard 42 of the vehicle.

Said input face 38 corresponds to one of the sides of a contour of said blade 21 and said outlet face 40 corresponds to the other sides of said contour. The latter may be rectangular, said inlet face 38 being defined by one of the long sides of said blade 21 and said outlet face 40 by its other three sides.

Said light source 30 of said transmission device comprises at least one light-emitting diode 44, here a plurality disposed along said input face 38. The said diode (s) may be red, orange and / or of another color. In other words, said light-emitting diodes 44 may all be of the same color for a high light intensity or of different colors to vary the coloration chosen for the edge of the blade 21.

Said transmission device here comprises a flexible conductor 46 for supplying said diodes 44, said diodes 44 being disposed on said flexible conductor. Said flexible conductor 46 may be fixed on the dashboard 42 and / or to said blade 21 by means of securing means 47.

However, said display advantageously comprises means for activating the light source 30. They may be configured to alternately operate said light source 30, in particular to give it a function of repeating the flashing light by alternating illumination of the edge of said light source 30. The electroluminescent diode (s) 44 employed are then, for example, orange in color. Said image generation device 11 of said display comprises here control means 33 (Figure 1), including the means for controlling the power supply of its light sources. Said control means are advantageously configured to control further said means for activating the light source of said transmission device.

A light sensor 13 is integrated here in said image generation device 11 so as to receive a light beam of direction opposite to that 19 of the emission of said image, namely directed towards the image generation device 1 1. This light beam in the opposite direction corresponds to the light atmosphere present at said image level, for example at the background level, in particular the light atmosphere transmitted by said semi-reflective plate 21 or said windshield allowing the display of said virtual image 9, as illustrated in Figure 1.

Claims

claims

An image transmission device for a display (1) for displaying in the field of view of a conductor (5) a virtual image (9), said transmission device comprising:

an optical element (21) semi-reflecting, configured to transmit light rays making it possible to display said virtual image in said field of vision, said optical element (21) being further configured to guide the light,

a light source (30) emitting a light beam,

said light source (30) and said optical element (21) being located relative to each other so that said beam is emitted by said optical element (21) operating as a light guide.

2. Device according to claim 1 wherein said light source (30) comprises at least one light emitting diode (44).

3. Device according to any one of claims 1 or 2 in said optical element (21) is a blade.

4. Device according to claim 3 wherein said blade (21) is semi-reflective.

5. Device according to any one of claims 3 or 4 wherein said blade (21) comprises two faces (32, 34) transmitting said spokes (19), said faces being connected by a wafer (36).

6. Device according to claim 5 wherein said wafer (36) comprises a first portion (38) forming the input face of the light beam.

7. Device according to claim 6 wherein said wafer (36) comprises a second portion forming an output face (40) of the light beam.

8. Device according to any one of claims 6 or 7 wherein said input face (38) is configured to be vis-à-vis a dashboard (42) of the vehicle.

9. Device according to any one of claims 6 to 8 wherein said input face (38) corresponds to one of the sides of a contour of said blade (21) and said outlet face (40) corresponds to other sides of said contour.

The device of any one of claims 6 to 9 wherein said light source (30) comprises a plurality of light emitting diodes (44) disposed along said input face (38).

11. Device according to any one of claim 9 wherein said device comprises a flexible conductor (46) for feeding said diodes

(44), said diodes (44) being disposed on said flexible conductor (46).

12. Display (1) comprising an image transmission device according to any one of the preceding claims.

13. Display according to claim 12 comprising means for activating the light source (30).

The display of claim 13 wherein said activation means is configured to alternately operate said light source (30).

15. Display according to claim 14 comprising control means (33) of an image generating device (34) of said display, said control means (33) being configured to drive said activation means.

16. A display according to claim 15 wherein said device for image generation comprises a light source provided with one or more laser diodes.