EP3482284A1

EP3482284A1 - Head-up display and method for controlling an image-generation device of a head-up display

Info

Publication number: EP3482284A1
Application number: EP17733860.5A
Authority: EP
Inventors: Michael Irzyk
Original assignee: Valeo Comfort and Driving Assistance SAS
Current assignee: Valeo Comfort and Driving Assistance SAS
Priority date: 2016-07-05
Filing date: 2017-06-30
Publication date: 2019-05-15
Also published as: CN109997103A; FR3053804A1; FR3053804B1; WO2018007269A1; US20190244553A1

Abstract

The invention relates to a method for controlling an image-generation device (11) of a head-up display (10) for a motor vehicle, comprising: a step of acquiring data relating to the operation and/or the environment of the motor vehicle, and a step of controlling the display, via the image-generation device, of at least two driving-assistance information items, based upon the acquired data. According to the invention, during the control step, the light intensity of at least one information item is time-modulated with respect to the light intensity of the other information item. The invention also relates to a head-up display comprising a computer capable of performing the above-mentioned method.

Description

HEAD-UP DISPLAY AND METHOD FOR CONTROLLING A GENERATING DEVICE

PICTURES OF A HEAD-UP DISPLAY

TECHNICAL FIELD TO WHICH THE INVENTION RELATES The present invention relates generally to devices for assisting the driving of motor vehicles.

It relates more particularly to a method for controlling an image generation device of a head-up display for a motor vehicle, comprising:

a step of acquiring data relating to the operation and / or the environment of the motor vehicle, and

a step of generating an image, by the image generation device, comprising at least two driving assistance information, as a function of the data acquired.

It also relates to a head-up display for a motor vehicle, comprising:

an image generation device,

a system for projecting a virtual image into the field of vision of the driver of the motor vehicle, and

a computer adapted to acquiring data relating to the operation and / or the environment of the motor vehicle, and to controlling the image generation device such that it generates an image comprising at least two information to assist driving, depending on the data acquired.

BACKGROUND TECHNOLOGY

To facilitate and make safer driving a motor vehicle, we want to prevent the driver is forced to look away from the road he takes.

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

Two types of head-up displays are particularly known.

The displays of the first type 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 output of the diffuser thus forms an image, which can then be projected into the field of vision of the driver of the vehicle.

The displays of the second type use a screen that generates an image, which is then projected into the driver's field of vision.

The variety of information that can be projected into the driver's field of vision is so great that it is necessary to select those that seem most useful to the driver. In fact, it is possible to display information relating to the operation of the vehicle (speed, fuel level, automatic cruise control speed), or guidance information (route to be followed, distance from the next junction, name of the route taken , risk of traffic congestion, etc.), or even safety information (development of obstacles, speed limit, etc.).

Currently, only a few information items are selected to be projected in the field of view of the driver so as not to overload the driver information and not to disrupt in his conduct.

The head-up displays therefore have two major ergonomic constraints.

The first constraint is that the number of information projected in the driver's field of vision must remain limited.

The second constraint is that in the presence of many information fixed in content, form, brightness, the driver gets used to them and no longer takes care of information that could, at a given moment, be particularly important.

OBJECT OF THE INVENTION

In order to overcome the aforementioned drawbacks of the state of the art, the present invention proposes to gradually eliminate the non-value-added information, so that only useful information remains in the driver's field of vision.

More particularly, according to the invention, a control method is proposed as defined in the introduction, in which the control step is intended to modulate in time the light intensity of at least one piece of information relative to one another. the light intensity of the other information (the latter can be considered equal to a nominal reference light intensity).

Thus, thanks to the invention, it is possible to reduce the light intensity of the least important information, to highlight only those that must be considered primarily by the driver of the vehicle.

It is even possible to remove, at least momentarily, certain information after they have lost their interest. It will also be possible to reveal new information when it is deemed important.

It is therefore understood that it will be possible to project in the driver's field of vision a large amount of information, but at different times.

Preferably, the deletion of information will be done gradually, so as not to unnecessarily attract the eye of the driver. On the contrary, the display of new important information will preferably be done fairly quickly, to attract the eye of the driver.

Other advantageous and non-limiting features of the control method according to the invention are the following:

- In the control step, it is expected to modulate the light intensity of said information continuously;

in the acquisition step, it is intended to acquire the value of at least one parameter relating to the traffic conditions of the motor vehicle, and in the control step, it is intended to modulate the light intensity. said information as a function of the variations of the value of said parameter;

in the control step, the luminous intensity of said information is modulated to vary between a plateau of maximum intensity and a plateau of minimum intensity;

- It is expected to vary the light intensity of said information faster when the light intensity is increased than when the light intensity is reduced;

as long as the value of said parameter remains substantially constant, the luminous intensity of said information is controlled to remain equal to the minimum intensity step, and as soon as the value of said parameter varies substantially, the luminous intensity of said information is increased. up to the plateau of maximum intensity where it is kept constant, then, as soon as the value of the parameter has remained substantially constant for a predetermined duration, the light intensity of said information is reduced to the minimum intensity level.

The invention also proposes a head-up display as defined in the introduction, in which the image generation device is adapted to independently vary the light intensity of each piece of information, and in which the computer is adapted to control the image generating device so as to modulate in time the light intensity of each information with respect to each other.

Other advantageous and non-limiting characteristics of the head-up display according to the invention are the following:

the computer is adapted to acquire the value of at least one parameter relating to the traffic conditions of the motor vehicle and to vary the light intensity of one of the information taking into account variations in the value of said parameter;

the computer is adapted to vary the light intensity of one of the information between a plateau of maximum intensity and a plateau of minimum intensity.

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 view of a first embodiment of a head-up display according to the invention;

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

FIGS. 3A and 3B are synchronous graphs illustrating the variation in time of the speed of a motor vehicle (FIG. 3A) and the light intensity of information appearing on an image generated by a head-up display ( Figure 3B); and

FIG. 4 is a schematic view of an image generated by a head-up display.

FIGS. 1 and 2 show two embodiments of a head-up display 10 for equipping a vehicle, for example a motor vehicle.

In these two embodiments, the head-up display 10 comprises an image generation unit 1 1 driven by a computer 13, and an optical projection unit 12.

In the first embodiment illustrated in FIG. 1, the image generation unit 11 is of the "light modulation" type. It includes a screen, here an LCD (or LCD for "Liquid Crystal Display") thin-film transistors (or TFT for "Thin-Film Transistor"). It also includes a backlight device located at the back of the screen. This backlighting device comprises a plurality of light-emitting diodes distributed behind the liquid crystal of the screen.

In the second embodiment illustrated in FIG. 2, the image generation unit 11 is of the "emissive" type. It comprises a diffuser 1 6 and a scanning unit which generates a light beam of variable direction so as to scan the rear face of the diffuser 1 6. The scanning unit more specifically comprises a beam forming module 14 and a mirror mobile 15, for example made in the form of an electromechanical microsystem (or MEMS for "MicroElectroMechanical System").

The beam forming module 14 typically comprises three monochromatic light sources, such as laser sources, whose respective (monochromatic) light beams are combined (for example using dichroic mirrors) to form the polychromatic light beam ( here laser) emitted at the output of the beam forming module 14. This light beam generated by the beam forming module 14 is directed towards the moving mirror 15, whose orientation is controlled by a control module so that the reflected light beam (by the movable mirror 15) sweeps the rear face of the diffuser 1 6.

In these two embodiments, the image generation unit 1 1 makes it possible, under the control of the computer 13, to generate an image that the projection optical assembly 12 will be able to project into the driver's field of view when the look of the latter is turned towards the road.

In the two embodiments shown in FIGS. 1 and 2, the projection optical assembly 12 is more specifically designed to project a virtual image lmg ₀ in the field of vision of the driver of the vehicle, at a distance from the driver that is greater than that separating the driver from the windshield 1 (so that the eyes of the driver do not have to perform work of accommodation to collect projected information).

For this purpose, the optical projection unit 12 comprises a deflection optical system 17 and a combiner 18 placed in the field of vision of the driver of the vehicle.

The optical return system 17, which here only includes a folding mirror, makes it possible to send the image generated by the image generation unit 1 1 to the combiner 18.

The combiner 18 makes it possible to reflect this image in such a way that it appears to the driver as if it were displayed outside the vehicle.

Here, this combiner 18 is formed by a semi-reflecting blade which is arranged in the passenger compartment of the motor vehicle, between the windshield 1 of the vehicle and the eyes of the driver, and which is curved so as to enlarge the size of the vehicle. virtual image lmg ₀ seen by the driver.

Alternatively, the semi-reflective element could be the windshield itself.

In the two embodiments shown in FIGS. 1 and 2, the computer 13 is designed to drive the image generation unit 11, so that the head-up display 10 can project useful information into the field. of vision of the driver.

This computer 13 comprises a processor (CPU), a random access memory (RAM), a read only memory (ROM), analog-digital converters (A / D), and different input and output interfaces.

Thanks to its input interfaces, the computer 13 is adapted to receive input signals from different sensors or other computers. For example, the computer 13 may be connected to the main communication network of the vehicle (BUS-CAN type), in order to read the data sought.

The computer 13 can thus acquire various data relating to the operation and / or the environment of the motor vehicle.

It thus acquires data relating to the operation of the vehicle, such as, for example: - the instantaneous speed V of the motor vehicle,

- the remaining fuel level,

- the speed of regulation chosen by the driver in the automatic cruise control.

This data is for example acquired through sensors fitted to the vehicle.

The computer 13 also acquires vehicle guidance data, such as, for example:

- the route to take,

- the distance to the next lane change,

- the name of the route taken,

- the presence of bottling,

- time and distance remaining before arrival at destination.

These data are for example acquired through a navigation system and geolocation fitted to the vehicle.

The computer 13 finally acquires data relating to the safety of the vehicle, such as, for example:

the presence of obstacles and the distance to each obstacle (obtained for example by means of a camera or thanks to a sensor of the RADAR or LIDAR type),

- the speed limit Vmax allowed on the taxiway

(obtained for example by a camera filming the roadside panels, or thanks to the navigation and geolocation system).

These input signals are, if necessary, sampled and digitized. They are then stored in the random access memory of the computer 13.

The read-only memory stores data used in the context of the method described below.

It stores in particular a computer application, consisting of computer programs comprising instructions whose execution by the processor allows the implementation by the computer 13 of the method described below.

Finally, thanks to its output interfaces, the computer 13 is adapted to transmit control signals to the image generation device 1 1, so that the latter generates an image with different distinct information, useful for driving the image. motor vehicle. In FIG. 4, to illustrate the present invention, it is shown schematically what the driver can see through the combiner 18.

He can first observe the road 30 which extends in front of him and on which circulates here a motor vehicle 31 which precedes it.

It can also see, in superposition of the route 30, the virtual image lmg ₀ generated by the image generation device 1 1.

In the particular embodiment shown in FIG. 4, several "information" can be distinguished on this virtual image lmg ₀ , namely:

a fuel level information item 21, which corresponds to an estimate of the distance that can still be traveled before a fuel outage,

an instantaneous speed information 22, which corresponds to the instantaneous speed of the motor vehicle (this speed possibly being filtered beforehand so as not to take into account disturbances or insignificant variations in speeds),

a speed limit information 23 which corresponds to the authorized speed limit on the route taken (this information being equal to the speed limit Vmax acquired by the computer),

a regulation speed information 24, which corresponds to the speed that the driver has programmed on his cruise control,

a direction information 25 corresponding to the direction of the next branch,

a distance information before branching 26 which corresponds to the distance separating the vehicle from this next branch line,

an obstacle information 27 presented here in the form of a line highlighting the presence of an obstacle, namely here the motor vehicle 31, and

a distance information 28 which corresponds to the distance separating the vehicle from this obstacle.

According to a particularly advantageous characteristic of the invention, the computer 13 is adapted to control the image generation device 1 1 so as to modulate in time the light intensity of at least one information with respect to the light intensity. other information.

For this, the image generation device 1 1 is adapted to independently vary the light intensity of each image information. virtual lmg ₀ .

In the case of the first embodiment shown in FIG. 1, this variation in light intensity can for example be done by varying the light intensity emitted by some of the light-emitting diodes of the backlighting device.

In the case of the second embodiment shown in FIG. 2, this variation in light intensity can for example be done by varying the light intensity emitted by some or all of the monochromatic light sources.

In any event, the computer 13 is adapted to control the image generation device 1 1 by transmitting to it a set of instructions comprising data relating to the shape of the image to be displayed and data relating to the luminous intensity. with which the different parts of the image should appear.

We can now describe an example of a control algorithm implemented by the computer 13 to drive the image generation device 1 1 accordingly.

The algorithm presented here will be repeated at regular and reduced time intervals.

During a first step of this algorithm, the computer 13 acquires the data relating to the operation and / or the environment of the motor vehicle (listed above). It acquires, in particular, the instantaneous speed V of the motor vehicle and the speed limit Vmax allowed on the traffic lane used by the vehicle.

During a second step, the computer 13 processes all the data acquired so as to derive driving assistance information 21 to 28 (listed above), which can be projected into the field of view of the vehicle. driver.

During a third step, the computer 13 generates an image that includes said driving assistance information 21 to 28, then calculates and assigns each of these information a light intensity. This luminous intensity corresponds to the intensity with which the corresponding information must be displayed.

According to the invention, the computer 13 modulates in time the intensity at least one of these driving assistance information items 21 to 28.

For this purpose, for example, the manner in which the computer 13 calculates the luminous intensity of the three pieces of information such as the instantaneous speed information 22, the speed limitation information, can be illustrated by way of illustration. 23 and the fuel level information 21.

Since the instantaneous speed information 22 is considered essential at all times, its luminous intensity l ₂ 2 is fixed so as to remain constantly equal to a maximum intensity l _max .

As will be well described later in this discussion, this maximum intensity l _max may be invariable or may vary on the contrary, for example depending on the ambient light conditions.

The fuel level information 21 is considered essential only when the distance that can still be traveled before failure passes below a predetermined threshold (for example 200 kilometers). Therefore, its luminous intensity l ₂ i is set equal to zero as long as said distance remains greater than this threshold, then it is set equal to the maximum intensity l _max when said distance falls below this threshold.

The speed limit information 23 is considered as sometimes essential, given the traffic conditions of the motor vehicle. Therefore, its luminous intensity l ₂ 3 is modulated in time according to a parameter relating to the traffic conditions of the motor vehicle.

More specifically, in the exemplary embodiment considered, the speed limit information 23 is considered essential only when the speed limit Vmax changes. Therefore, its luminous intensity l ₂ 3 is time-modulated as a function of the speed limit variations Vmax.

To illustrate the invention, FIG. 3A shows the evolution of the instantaneous speed V of the motor vehicle. We can first explain that at time t ₀ , the speed limit Vmax increases, since it decreases at time ti.

It is then observed in this same Figure 3A that the instantaneous speed V of the vehicle evolves to adapt to these changes in speed limitation, with a slight delay.

FIG. 3B shows, in a synchronous manner, the variation corresponding to the light intensity l ₂ 3 assigned by the computer 13 to the speed limit information 23.

As shown in this FIG. 3B, it is here chosen to display the speed limitation information 23 after each change of speed limit Vmax, then to make this information disappear after a predetermined duration Ai, if the speed limit Vmax has not changed during this predetermined time Δΐ.

The luminous intensity l ₂₃ is more precisely modulated to vary between a maximum intensity step l _max and a minimum intensity level l ₀ .

Thus, as shown in FIG. 3B, initially, and then as long as the speed limit Vmax remains unchanged, the luminous intensity l ₂ 3 is controlled to remain equal to the minimum intensity step l ₀ .

Then as soon as the speed limit is changing Vmax (at times t ₀ and t i), the luminous intensity l ₂ 3 is increased to a maximum intensity level l _max where it is kept constant at least during the duration Δΐ .

Then, when the speed limitation Vmax has remained constant during this time Δΐ, the light intensity l ₂ 3 is gradually reduced to the minimum intensity level l ₀ .

Here, to avoid any visual discomfort of the driver, the variation of the luminous intensity ₂₃ of the speed limitation information 23 is continuous (and not abruptly, in stages).

As shown in FIG. 3B, it is intended to vary the light intensity ₂₃ more rapidly when it is desired to increase it (at times t ₀ and t-1, after a change in speed limit V max) than when we would like to reduce (at times t ₀ 'and t when the speed limit has not advanced during the period Δΐ).

In this way, the driver of the vehicle will not be disturbed by the gradual erasure of the speed limitation information 23. On the other hand, his eyes will be attracted by the sudden appearance of the speed limitation information 23.

The brightness transition between the steps can be given in the form: In this equation, t, is equal to the time from which the \ ₂₃ light intensity starts to vary with a change of level (Figure 3B, it will be successively instants to, to ', ti , tT).

The constant I H corresponds to the maximum intensity that the image generation device 11 can provide.

The coefficient a, will be chosen in such a way that the transition of brightness is done more or less quickly. In practice, this coefficient a, will be chosen greater at times t ₀ and ti (during a speed limit change Vmax) than at times t ₀ 'and tT.

The coefficient will be between 0 and 1 (limits included).

Its value can be modified to take into account the ambient light. It can for example be reduced in night display mode and increased in daytime display mode.

Note that in this case, this change in light intensity will simultaneously affect all the information displayed, not just a part of them. Otherwise formulated, the value of the maximum intensity l _max assigned to the instantaneous speed information 22 and fuel level information 21 will vary in the same manner, to take account of the ambient brightness.

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

Thus, it will be possible in particular to provide that the parameter which is taken into account to control the intensity \ ₂₃ is not the speed limit Vmax, but rather the instantaneous speed V of the vehicle. Thus, as the instantaneous speed of the vehicle is "substantially constant" (that is to say as long as the speed differences remain below a determined threshold for a given period of time), it can maintain the intensity \ ₂₃ at a low level. On the other hand, it is possible to increase the intensity _{23 as} soon as the speed of the vehicle changes sharply. The advantage of this solution is that if the speed limit Vmax has not changed but for any reason the vehicle is accelerating suddenly, the speed limit information 23 will be displayed again to remind the driver which the speed limit Vmax.

It might also be possible to vary the intensity of the information vehicle guidance (eg direction information 25, distance information before branching 26, information of the name of the route taken, ...). Thus, by way of example, it will be possible to display the distance information before branching 26 only periodically and / or when approaching this branch. As another example, it will be possible to display the name of the road taken only when the vehicle is driving in built-up areas.

Claims

1. A method of driving an image generation device (1 1) of a head-up display (10) for a motor vehicle, comprising:

a step of acquiring data (V, Vmax) relating to the operation and / or the environment of the motor vehicle, and

a step of generating an image, by the image generation device (1 1), comprising at least two driving assistance information (21-28), as a function of the data (V, Vmax) acquired; ,

characterized in that, in the generating step, the light intensity (I23) of at least one information (23) is temporally modulated with respect to the light intensity (I22) of another information (22).

2. Control method according to the preceding claim, wherein, in the generating step, it is expected to modulate the light intensity (I23) of said information (23) continuously.

3. Driving method according to one of the preceding claims, wherein:

in the acquisition step, it is intended to acquire the value of at least one parameter (Vmax) relating to the traffic conditions of the motor vehicle, and

- In the generation step, it is expected to modulate the light intensity (I23) of said information (23) according to the variations of the value of said parameter.

4. Control method according to one of the preceding claims, wherein, in the control step, the light intensity (I23) of said information (23) is modulated to vary between a maximum intensity step (l _max ) and a minimum intensity level (l ₀ ).

5. Driving method according to the two preceding claims, wherein:

- as long as the value of said parameter (Vmax) remains substantially constant, the luminous intensity (I23) of said information (23) is controlled to remain equal to the minimum intensity level (I _0), and

- as soon as the value of said parameter (Vmax) varies substantially, the luminous intensity (I23) of said information (23) is increased to the intensity level maximum (Imax) where it is kept constant, then, as soon as the value of said parameter (Vmax) has remained substantially constant for a predetermined duration (Δΐ), the luminous intensity (I23) of said information (23) is reduced until at the minimum intensity level (l ₀ ).

6. Driving method according to one of the two preceding claims, wherein it is intended to vary the light intensity (I23) of said information (23) faster when the light intensity is increased than when the light intensity is reduced.

Head-up display (1 0) for a motor vehicle, comprising:

an image generation device (1 1),

a projection system (1 2) of a virtual image in the field of vision of the driver of the motor vehicle, and

a computer (1 3) adapted to acquire data (V, Vmax) relating to the operation and / or the environment of the motor vehicle, and to control the image generation device (1 1) in such a way that it generates an image comprising at least two driving assistance information (21-28), based on the data (V, Vmax) acquired,

characterized in that the image generation device (1 1) is adapted to independently vary the light intensity of each information (21-28), and

in that the computer (1 3) is adapted to control the image generation device (1 1) so as to modulate in time the light intensity (I23) of each piece of information (21-28), one by report to the other.

8. Head-high display (1 0) according to the preceding claim, wherein the computer (13) is adapted to acquire the value of at least one parameter

(Vmax) relating to the traffic conditions of the motor vehicle and modulating in time the light intensity (I23) of one of the information (23) taking into account variations in the value of said parameter (Vmax).

9. Head-high display (1 0) according to one of the two preceding claims, wherein the computer (1 3) is adapted to vary the light intensity (I23) of one of the information (23) between a stage of maximum intensity (l _max ) and a minimum intensity level (l ₀ ).