HEADS-UP DISPLAY FOR A MOTOR VEHICLE

Abstract

The invention relates to a heads-up display (1) comprising —an image generator (3), —a semi-reflecting display area (7) receiving light beams from said image generator (3), —characterized in that the semi-reflecting area (7) comprises at least one opaque portion or can be rendered opaque.

Claims

1. A head-up display device comprising: an image generator; and a semi-reflecting display area receiving light beams from said image generator, wherein the semi-reflecting area comprises at least one portion which is opaque.

2. The display device as claimed in claim 1, wherein the semi-reflecting area is formed by a semi-reflecting lamina configured to be placed at the level of the dashboard in front of a windscreen.

3. The display device as claimed in claim 1, wherein the semi-reflecting area is formed by a windscreen of a motor vehicle.

4. The display device as claimed in claim 1, wherein the semi-reflecting area is made from an electrochromic glass.

5. The display device as claimed in claim 4, wherein the electrochromic glass is formed by a sheet of semi-reflecting glass and an electrochromic film stuck on the sheet of glass.

6. The display device as claimed in claim 4, further comprising a control unit configured for commanding the making opaque of the semi-reflecting area on reception of a control signal.

7. The display device as claimed in claim 6, wherein the control signal is a warning signal.

8. The display device as claimed in claim 6, wherein the control signal is a signal of a reading mode during automatic driving.

9. The display device as claimed in claim 1, wherein the semi-reflecting area is entirely opaque.

10. The display device as claimed in claim 1, wherein the semi-reflecting area comprises a single portion which is opaque, the portion being a proximal portion with respect to a dashboard.

11. The display device as claimed in claim 1, wherein the semi-reflecting area comprises a self-cleaning coating.

Description

[0028] Other advantages and features will become apparent on reading the description of the invention and the appended drawings in which:

[0029] FIG. 1 shows a head-up display device in a diagrammatic manner,

[0030] FIG. 2 shows a representation of a semi-reflecting lamina according to a first embodiment in a cross-sectional view,

[0031] FIG. 3 shows an image of the display device shown in FIGS. 1 and 2 in operation,

[0032] FIG. 4 shows a representation of a semi-reflecting lamina according to a second embodiment in a cross-sectional view,

[0033] FIG. 5 shows an image of the display device shown in FIG. 4 in operation.

[0034] Identical elements have the same reference numbers in all of the figures.

[0035] An example embodiment will now be described with reference to the figures.

[0036] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily signify that each reference relates to the same embodiment, or that the features apply solely to a single embodiment. Single features of different embodiments can also be combined in order to provide other embodiments.

[0037] FIG. 1 shows a diagram of a head-up display device 1.

[0038] This display device 1 comprises an image generating device 3.

[0039] This image generating device 3 comprises for example a liquid crystal display screen, in this case a liquid crystal display screen (LCD screen) 5 for example comprising thin film transistors, and an integrated backlighting device (not shown). The liquid crystal display screen 5 can be an active or passive matrix one. The thin film transistor liquid crystal screen 5 is commonly called a TFT-LCD (standing for “Thin-Film Transistor Liquid Crystal Display” in English) screen and allows the formation of an image by the image generating device 3.

[0040] The image generating device 3 therefore forms an image with the help of the liquid crystal display screen 5.

[0041] Downstream of the screen 5 in the direction of movement of the light beams, the display device 1 comprises at least one semi-reflecting lamina 7, of straight or slightly curved shape in cross-section, and a reflection device 9 interposed in the path of the image between the screen 5 and the semi-reflecting lamina 7, the reflection device 9 comprising one or more flat or concave mirrors, as shown in FIG. 1.

[0042] The semi-reflecting lamina 7 forms a semi-reflecting display area receiving light beams from said image generator.

[0043] This lamina 7 has for example a reflective power at least equal to 20%, which allows the user to see the road traveled by the vehicle through the lamina whilst allowing him to see the displayed image.

[0044] According to a variant which is not shown, it is possible to provide for the semi-reflecting display area to be formed by a part of the windscreen of the vehicle. This would make it possible to save having the semi-reflecting lamina of the head-up display device 1, but would assume that the windscreen has, in the display area, a shape adapted for the display device 1, notably in terms of curvature and a suitable semi-reflective power, for example by applying a semi-transparent film on the windscreen.

[0045] In this figure, the path of the image is symbolized by three arrows 11 drawn in dotted line which are reflected on the reflection device 9 before being displayed through the semi-reflecting lamina 7.

[0046] The latter makes it possible, via a magnification and/or by transparency, a display of the image beyond the semi-reflecting lamina, notably beyond the windscreen of the vehicle, at the level of a virtual screen 13.

[0047] FIG. 2 shows an embodiment of a semi-reflecting lamina 7 in cross-section.

[0048] According to this example, the lamina 7 is for example formed by two layers of glass 15 and 17, sandwiching for example a liquid crystal film 19 electrically connected to a control unit 21 in order to be able to control, by application of a suitable electric field orienting the liquid crystals or changing their color, the opacification or not of the lamina 7. It is then said that the semi-reflecting lamina 7 is produced by an electrochromic glass.

[0049] In the present invention, the word “glass” equally refers to a silica glass and to a glass for example made of plastic such as crystal polycarbonate.

[0050] As a variant, it is possible to use a lamina 7 formed by a single layer of glass upon which is stuck an electrochromic film, for example made white and opaque during the application of an electric current and transparent in the absence of current.

[0051] According to the example shown in FIG. 2, the lamina 7 is wholly electrochromic, that is to say it can, according to a control signal from the control unit 21, be made completely opaque.

[0052] According to a variant which is not shown, only one part of the lamina 7, for example the lower part, proximal to a dashboard, can be made opaque, for example due to the fact that the liquid crystal film 19 is present only in the lower part of the lamina 7.

[0053] The use of at least one portion which is opaque or which can be made opaque makes it possible to increase the contrast of the displayed image and to make the contrast constant. For warning messages in particular, the user can be better alerted. During automatic driving, the user can read the information projected on the semi-reflecting area 7 with increased comfort and without risk of discomfort. Moreover, as the semi-reflecting area 7 is in the user's field of vision, the latter can have the use of a large sized screen without having to turn his head.

[0054] The control unit 21 is for example configured for commanding the making of the semi-reflecting lamina 7 opaque on reception of a control signal, such as a warning signal, or a reading mode signal during automatic driving.

[0055] Thus, the opacity is only obtained in the authorized situations, for example during automatic driving of the vehicle, or imperative situations, for example in cases of warning.

[0056] FIG. 3 shows an image of the display device shown in FIGS. 1 and 2 in operation. In this example, the vehicle has approached too close to a vehicle 23 preceding it. This generates a warning signal which is also transmitted to the control unit 21 making the semi-transparent lamina 7 completely opaque.

[0057] Thus the user's attention is drawn by the opacification and due to its opaque appearance the information delivered is more visible, notably with more contrast.

[0058] FIG. 4 shows a representation of a semi-reflecting lamina 7 according to a second embodiment in a cross-sectional view.

[0059] In this embodiment, the semi-reflecting lamina 7 comprises a single portion 25 which is permanently opaque or which can be made opaque, this portion 25 being a proximal portion with respect to a dashboard 27 of the vehicle.

[0060] This can be produced for example by a black film affixed over the portion 25 on the rear surface 29 of the semi-reflecting lamina 7.

[0061] FIG. 5 shows an image of the display device according to the embodiment shown in FIG. 4 in operation. Whilst the semi-reflecting portion of the lama 7 indicates for example a direction to follow to the driver, the lower portion 25 indicates the arrival of an email with good contrast.

[0062] Moreover, the semi-reflecting lamina 7 can comprise a self-cleaning coating on its front surface 31 receiving the light beams.

[0063] Thus, in the long term, the deposit of dust which can degrade the legibility of the information projected to the semi-reflecting zone 7 is avoided.

[0064] It can therefore be understood that the comfort of the user can be significantly improved by the fact of at least partly opacifying the semi-reflecting lamina 7 preventing him from discomfort whilst reading on the head-up display device 1 and drawing his attention in dangerous driving situations.