JP6370793B2 - Head-up display device and method - Google Patents

Description

  The present invention relates to a head-up display device commonly referred to as an acronym for HUD.

  Such devices are generally implemented in aircraft, trains, or ships, but are also implemented in motor vehicles (passenger cars, trucks, etc.).

  Current transportation means are increasingly equipped with electronic driving support systems to increase safety and enhance driver comfort.

  Such a system is associated, for example, with a front display device of the HUD (Head Up Display) type. This type of device achieves safe driving by making it easier for the driver to use information about the vehicle, that is, by reducing the line of sight switching between driving and display information.

  It is known that such information can be displayed on various displays.

  In practice, in the prior art, these displays may be associated, for example, with LCD (Liquid Crystal Display) technology screens located above the handle.

  However, such placement in the vehicle poses problems related to structural, ergonomic and regulatory constraints.

  These displays can also be related to the head-up device described in International Publication No. WO2010139898 or French Patent No. 2914070. In practice, these devices are configured to transmit information through a partially reflecting plate glass or part of a vehicle windshield and / or a specific area, and the information optically projected from the light box. Has been specially processed to ensure display.

  However, these devices have the major drawback of being very bulky, especially because they consist of a unique light box that requires a considerable volume under the dashboard.

  In addition, as driving assistance and driving warnings related to embedded systems become more common, current displays, more specifically, dashboards are out of space, reduced size of displayed elements, information It is constrained by problems such as visibility and element identification.

  The present invention aims to solve these problems arising from the disadvantages of the prior art.

  The present invention aims to solve the problem related to the reduction of the volume of head-up display devices, and improves the readability of information that is likely to be displayed by these devices.

In order to achieve this object, one aspect of the present invention provides:
-Projection means for generating a light beam carrying the displayed image;
A partially reflective screen comprising at least one proximity display area and one remote display area arranged to display the image in a user field of view; and receiving a light beam from the projection means and alternating the light beam The present invention relates to a head-up display device for displaying at least one image, comprising an active element arranged to be transparent to the display area.

According to a specific embodiment,
The active element is linked to a light beam property management module capable of synchronizing the variation of the light transmission property of the active element as a function of the property;
-Active element is related to active light diffuser like PDLC film,
The proximity display area relates to the area of the partially reflective screen that contains luminescent particles suitable for the emission of visible wavelength radiation after absorption of the light beam;
-The projection means is a laser pico projector,
The active element is transmissive and is located between the projection means and the display area,
The active element is reflective and is arranged between the mirror and the projection means, said mirror being suitable for the reflection of a light beam emitted from the active element on the optical path towards the display area.

The present invention also includes the following steps:
-Generation by means of projection of the light beam carrying the displayed image;
-Display in the user field of view of said image in at least one proximity display area and one remote display area arranged on the partially reflective screen; and-by an active element of the light beam emitted by the projection means onto the display area The present invention relates to a head-up display method for displaying at least one image, comprising alternating transmission steps.

  Advantageously, the method comprises the step of synchronizing to variations in the light transmission characteristics of the active element as a function of the characteristics of the light beam from a management module for the characteristics linked to the active element.

  Other advantages and features of the present invention will become more apparent upon reading the following description of the preferred embodiment and referring to the following figures provided as illustrative and non-limiting examples: .

1 shows a laminated windshield according to one embodiment of the present invention. 1 illustrates the principle of excitation of luminescent particles in a windshield display area according to an embodiment of the invention. FIG. 4 shows an optical diagram for creating a virtual image in a partially reflective region of a windshield, according to one embodiment of the invention. Fig. 6 shows a transmissive active element in a light diffusing state, according to an embodiment of the invention. Fig. 5 shows a transmissive active element in a transmissive state according to an embodiment of the invention. Fig. 4 shows a reflective active element in a light diffusing state, according to one embodiment of the invention. Fig. 4 shows a reflective active element in a transmissive state according to an embodiment of the invention. Fig. 4 shows an optical diagram illustrating the construction of two parallel images from a single projection means according to an embodiment of the invention. FIG. 3 shows a diagram associated with generating an interleaved image from an information flow according to an embodiment of the present invention. 1 illustrates the principle of image interleaving according to one embodiment of the present invention. FIG. 4 shows a diagram illustrating image addressing in interleaved image mode, according to one embodiment of the invention. 1 illustrates the principle of interleaving images of different sizes according to an embodiment of the invention. FIG. 6 shows a diagram illustrating image addressing in an alternate image mode according to an embodiment of the invention. Fig. 4 illustrates projection means with active elements according to an embodiment of the invention. Fig. 4 shows an optical diagram illustrating the virtual image and reflection of an excitation source from a single projection means, according to an embodiment of the invention. Fig. 4 shows the position of a display area according to an embodiment of the invention.

A head-up display device for displaying at least one image comprises:
At least one projection means 4 for generating a light beam carrying the displayed image;
A partially transmissive and partially reflective screen 7 including at least one proximity display area and one remote display area, arranged to display the image in a user's field of view, and a projector for directing a light beam to the display area; An optical system that defines an optical path to one of the display areas;
A non-planar mirror, which makes it possible to increase the distance of the optical path,
An initial image that is all transmitted along the optical path is provided with a light diffusing element generated thereon. Depending on the technology employed, this diffusing element may be arranged in the projector 4.

  Projection means 4 generally but not entirely relates to any projection means 4 used in conventional head-up display devices. For example, it may be a device based on a transmissive mode backlight active liquid crystal, a device based on a reflective mode backlight active liquid crystal, a pico projector incorporating a matrix of micromirrors reflecting a light source, or a laser pico projector.

  FIG. 11 shows a laser pico projector corresponding to a small video projector.

  This pico projector in particular comprises an input module 17 for video signals, an embedded logic module 18, a management module 8, a MEMS (micromechanical system) 24, and a horizontal / vertical scanning control module 25.

  As a modification, two or more MEMS can be used instead of one MEMS 24. Each MEMS is used for a given direction of space.

  The management module 8 is linked to three light sources 14, 15, and 16 having different wavelengths and is included in the pico projector. Management module 8 is also coupled to active element 5 by link 26.

  This management module 8 is suitable for driving each of the three light sources 14, 15, 16 in addition to the active element 5. Within the head-up display device, the active element 5 is arranged to receive a light beam from the projection means 4 and alternately transmit the light beam to the display area.

  In the context of this operation, a laser pico projector is suitable for reconstructing an image point by point with a refracted laser beam. The deflection of the laser beam can be obtained, for example, by a microelectromechanical system MEMS such as a micromirror. Implementation of such MEMS technology on a pico projector is described in International Publication No. WO2012000556 and US Publication No. 20112013855.

The projection means 4 such as a pico projector is provided with three laser light sources incorporated in an optical element, and each laser beam is aligned at the center of wavelength by using a mirror such as a dichroic mirror at the output. Yes. Each laser included in the projection unit 4 can address the color rendering property of the image by addressing the vector area as 800 nm to 620 nm, red 560 nm to 492 nm as green, and 482 nm to 445 nm as blue.

  Thus, different light sources with different wavelengths are grouped in a single projection means.

  In this head-up display device, the screen 7 relates to a vehicle windshield 7 which is basically transparent, for example, with respect to light rays from the outside of the vehicle. The windshield or screen 7 includes display areas having different color rendering properties of the light beam. The proximity display area is substantially transparent and comprises electroluminescent particles 32 suitable for emission of light radiation. The remote display area is partially reflective, especially for light beams from the inside of the vehicle. By having such a region with different light beam color rendering attributes with reflection attributes, the screen 7 corresponds to a partially reflective screen.

  In practice, the proximal display region is associated, for example, with a transparent region of the windshield 7 that contains luminescent particles 32 that emit radiation 33 of visible wavelength after absorption of the light beam 34. In practice, this area of the windshield is obtained by using luminous particles 32 contained in a film that is dissolved in PVB (polybutyl vinyl) or glued to one of the glossy surfaces of the windshield 7. can get. As shown in FIG. 1, the laminated windshield 7 is composed of two plate glasses 35 and 37 joined together by a PVB thermoplastic sheet 36.

  Photon emitting molecules are incorporated into the PVB layer 36 based on an encapsulation mechanism substantially similar to that described in French Patent No. 2914070B1, French Patent No. 2929016A1, or French Patent No. 2929017A1. It is.

  FIG. 2 shows these luminescent particles 32 that are excited by a certain wavelength of incident radiation 34 and that absorb this first wavelength of radiation and then emit a longer wavelength of radiation 33 that falls into another visible range. Illustrated.

  Thus, as already seen, for surfaces that contain luminescent particles, the excitation light must have a shorter wavelength than the visible light that is re-emitted. Therefore, the excitation light is in the ultraviolet region and may become invisible. In this case, the image is reconstructed in the plane of the photosensitive particles, ie in the plane of the windshield 7.

  Advantageously, the image displayed in such a region can be seen by all if the windshield 7 is in view. In order for all people to see, this area of the windshield 7 is to add a reflective surface so that the image produced by the system will pass through the windshield 7 and enter the view of all these people Or by the relative position of the elements.

  The remote display area relates to the partial reflection area of the windshield 7, for example. As shown in FIG. 3, the display area is arranged such that the virtual image is located at a distance of at least 1 m from the partial reflection screen 7. To do this, the projection means emits visible light and the image is then focused on the tip of this windshield 7. Only the driver can generally see this image.

  The characteristics of the light beam emitted by the projection means vary as a function of the display area.

  When the display area is associated with a transparent area of the screen 7 with luminescent particles, the wavelength of the light beam, or in this case the excitation beam, is shorter than the wavelength of the light beam emitted on the screen, here the windshield. In other words, for the emission that can be seen on the screen, ie on the windshield, the wavelength of the light beam (or excitation beam) may be in the ultraviolet region, but in the short wavelength visible region. May be.

  These wavelengths are in the range of 400-800 nm when the display area corresponds to the partially reflective area.

  In one embodiment, the head-up display device comprises any number of projection means 4. Each projection means 4 is associated with a display area from an optical system that defines an optical path between each projection means and the display area for directing the light beam to the display area.

  The vehicle comprises two separate projection means arranged separately in the vehicle for the two display areas, but not all.

  In general, a first projection means, such as any projection means 4 used in conventional head-up display devices, is used for image projection onto a remote plane over the area of the partially reflective windshield 7 and also includes laser pico A second projection means such as a projector is used to address the luminescent particles in the display area of the windshield 7.

  In another embodiment, contrary to the previous embodiment, the head-up display device comprises only a single projection means for displaying an image in at least two display areas.

  In this embodiment, the projection means for generating the light beam that bears the displayed image relates to, for example, a pico projector. The apparatus also comprises an active element 5 arranged to receive a light beam from the projection means and send the light beam via an optical path to the display area. This active element 5 is linked to a light beam property management module and is suitable for synchronizing the variation of the light transmission property of the active element 5 as a function of said property. This management module is included in the projection means and is suitable for driving various light sources included in the projection means and the active element 5.

  The active element 5 relates to an active diffuser of active light, such as a PDLC (polymer dispersed liquid crystal) film. The PDLC film comprises a mixture of liquid crystal and polymer having orientation characteristics that can vary as a function of the electric polarization of the crystal.

  This active element 5 is arranged downstream of the projection means. When electrical polarization is generated by the management module, the PDLC film becomes transparent. Conversely, when there is no electrical polarization, the film diffuses the light emitted by the projection means. Thus, the active element 5 can alternately switch between the two states of transmission and diffusion.

  When the projection means 4 is a laser pico projector, the source image is an image on the plane of the active diffuser when the active diffuser is diffusing, and when the active diffuser is transparent, the light beam is not deflected, Pass through the active diffuser.

  Therefore, by linking this active element 5 to the management module 18, it is possible to identify two display areas with a single projection means 4.

  Indeed, the management module 18 makes it possible to synchronize the power supply of the projection means 4 with the electric polarization source of the active light diffuser.

  For example, by synchronizing the electric polarization source of the active light diffuser and the power source of the projection means, here the excitation source of the fluorescent region of the windshield 7 containing the luminescent particles, on the remote plane of the partial reflection region of the windshield 7 On the active diffuser of the focused image, a diffuse image is obtained and on the diffuser for the image on the plane of the windshield 7 formed directly in the area of the windshield 7 containing the luminescent particles. Absent.

  This active element 5 may be transmissive or reflective.

  If the active element 5 is transmissive, it is placed between the projection means 4 and the display area, as shown in FIGS. 4A and 4B. Depending on the display area being addressed, the active element 5 changes state by becoming transparent or diffusive to light.

  An embodiment of the projection assembly of the apparatus is shown in FIG. This assembly comprises a projection means 4, a spherical mirror and a transmissive active element 5 and is arranged to produce a projection of the virtual image 21 and a reflection of the excitation source from a common source. The area 30 of the projection assembly is covered by an excitation scan after reflection by a spherical mirror. Points 23 and 22 correspond to the center of curvature of the spherical mirror and the objective focus of this mirror, respectively.

  5A and 5B illustrate a reflective active element arranged between the mirror 6 and the projection means 4. In this configuration, the projection means 4 and the display area are arranged on the same side with respect to the active element 5.

  Thus, the mirror 6 can reflect the light beam emitted from the active element 5 on the optical path at the display area.

  It will be clearly understood that the active element 5 does not transmit light when the active element 5 is in the diffuse state. Therefore, regardless of the state of the active element 5, light is always transmitted to the display area.

  This head-up display makes it possible in particular to generate an image focused from a transmissive or reflective active element 5 parallel to the remote plane of the display area of the partially reflective windshield 7. Indeed, in FIG. 6, the projection assembly of the presented apparatus comprises a projection means 4, an active element 5 and a spherical mirror. This projection means 4 is, for example, a color laser pico projector here, but is suitable for generating an image on an active element 5 which becomes alternately transparent. Thus, after passing through the optical path, the image is generated on any number of planes that generate the image source at various locations that generate parallel virtual images 21 on different projection planes.

  The invention also relates to a method of head-up display for displaying at least one image.

This method
Generating by at least one projection means 4 a light beam carrying the image to be displayed;
A step of displaying in a user field of said image in at least one predetermined display area arranged on the partial reflection screen 7, and an optical between the projection means 4 and the display area for directing the light beam to the display area Including the step of defining the path by an optical system.

  When this method is implemented by a head-up display device having an arbitrary number of projection means, and each projection means is associated with a predetermined display area, this method cooperates with each display area of the screen 7. A step of synchronizing the projection means, including a synchronization step executed from the management module 18;

When the head-up display device includes only a single projection means 4, this display method is:
Transmitting the light beam emitted by the projection means 4 from the active element 5 to the display area, and the variation of the light transmission characteristics of the active element 5, the light beam from the characteristic management module linked to the active element 5. Including synchronizing as a function of characteristics.

  FIG. 7 shows a diagram related to the interleaved image display mode in this head-up display device. The device receives an information flow 31 that is displayed in each of the display areas. In this information processing step 9, the device performs information separation according to each display area. In generation steps 10 and 11, an intended image is generated for each of the display areas. In step 12, these images are overlaid to be addressed 13 on the display area.

  In the step of transmitting the light beam to one of the display areas, the variation of the light transmission characteristics of the active element 5 makes it possible to alternately address the pixels of the displayed image to each display area. This variation in the light transmission characteristics of the active element 5 is generated at a frequency exceeding 24 Hz. In this way, interleaved images are generated and addressed to these display areas.

  The resolution of each of these images is lower than the maximum resolution of the display device. The total number of pixels available on each axis of each image is equal to the total number of pixels on each axis. Note that 100% of the addressable pixels are used.

  As illustrated in FIG. 8B, the display of the interleaved image is associated with a rapid drive of the active element 5 by the management module. Each time the display area changes, a change of state (transparent or diffuse) must be applied to the active element 5. The display of the interleaved image consists of driving the red, green and blue (excitation) light sources, and the active element 5 (diffuser) that switches between on and off modes to alternately address the pixels for each display area. ).

  In such a situation, the drive frequency is maximal and must consequently exceed the product of the image refresh rate (retinal afterimage, greater than 24 Hz) and the total number of pixels addressed by the system.

  The image interleaving mode implemented by this device is illustrated in FIGS. 8A and 9, in which the pixel 27 is included in the display area of the windshield 7 and emits radiation of visible wavelength after absorption of the light beam. A suitable luminescent particle excitation source is shown. Green pixels 28 and red pixels 29 are intended for the partially reflective display area. In FIG. 9, unlike FIG. 8, the interleaved image has a different size and is displayed with a different number of pixels.

  The advantages of generation and addressing on the interleaved image display area are related to the fact that this allows the display within the display area to be dynamically limited. Thus, the image display can be limited to the display area in the upper right corner of the image for a series of information, and can be limited to the lower right corner for other applications.

  In this case, the displacement of the display means relative to each range and each image of these display areas is maximized, thereby maximizing the energy provided to each range as a function of the projection means 4.

  A display mode with interleaved images is used with the active element 5 to enable driving and display at a high frequency within a clear display area.

  Alternatively, the image addressed to the display area may be a non-interleaved image or an alternate image. The image display mode is an alternate image addressing mode in the display area.

  As shown in FIG. 10, in this case, the transmission of the light beam to either of the display areas depends on the variation of the light transmission characteristics of the active element 5.

  Each time the display area changes, a change of state (transparent or diffuse) must be applied to the active element 5. This display of non-interleaved images is generated from driving the red, green and blue (exciton) light sources and from the active element 5 (diffuser). In this connection, the frequency of the projection means 4 is doubled as indicated by the red, green and blue light sources, and images are displayed alternately for each display area of the active element.

  When the red and green light sources are turned on for image addressing to the partially reflective display area, the active element 5 (diffuser) is in “diffuse” mode and the area of the windshield 7 containing the luminescent particles. The active element 5 (diffuser) is in “transparent” mode when the blue excitation source (exciton) is on for the diffusion of the image addressed to.

This transmission is
Fluctuating frequency exceeding 24 Hz:
This is done by the generation frequency of the light beam carrying the displayed image, corresponding to twice the variation frequency.

  Therefore, by doubling the frequency of the projection means 4, an image is displayed in each display area. For example, when the image is displayed against a remote plane, i.e. a partially reflective area of the windshield 7, the active element 5 diffuses the image. Also, the active element 5 is transparent when the image is displayed in the area of the windshield 7 containing luminescent particles.

  In this connection, if only a single image has to be displayed for a single display area in order to invalidate the retina afterimage, the projection means 4 must generate the image twice. Don't be. Similarly, the active element 5 is operated at an operating frequency that is at least equal to the afterimage of the retina, ie a frequency equal to half the operating frequency of the projection means 4. When the active module 5 is in a transparent state, the management module 18 displays the projection means 4 in such a way that an image intended to be displayed in the area of the windshield 7 containing the luminescent particles is displayed. 5 can be synchronized.

  The advantage of generating and addressing non-interleaved images on the display area is that the active element 5 only requires driving at a “low” frequency, as can be seen from FIG.

  Further, the display area can be dynamically limited within each area depending on the use of the assembly. Thus, the final emission of the assembly for each of the display areas is increased.

  The non-interleaved image display mode is used with the active element 5 that does not allow high frequency drive, but can at least double the number of images displayed per second relative to the retina afterimage. It is not used with the projection means 4.

  This head-up display device improves information display and driving comfort in the vehicle. This device provides a sufficient display area for information linked to navigation and multimedia information, for example.

  This device makes it possible to display information in the proximity display area, the area of the windshield 7.

  For example, the proximity display area may be appropriate for driving related information: vehicle speed, regulator / limiter / ACC speed, speed limit. As shown in FIG. 13, this display area can be arranged in a so-called “intermediate” position 19, ie in the driver's field of view at the bottom of the windshield 7. This display area does not cover all, but corresponds to the area of the windshield 7 containing the luminescent particles.

  The partial reflection area of the windshield 7 is called a remote display area, and safety and warning information: ACC target, accident warning ("collision"), distance warning ("inter-vehicle warning"), orbit drift warning ("lane departure warning") ) Can be used. As shown in FIG. 13, this display area can be placed in a so-called “up” position 20, ie in the driver's field of view above the proximity display area.

  This region is also suitable for navigation applications that are projected into the environment and may be displayed in a “pseudo augmented reality” mode.

  A new range appears with these two display areas. In fact, it is possible to use elements in a dynamic mode.

  For example, warnings are classified into three risk levels: no risk; obvious risk; obvious danger. Obvious risks can be displayed in the remote display area, and can be displayed in the proximity display area when this becomes an obvious danger. If there is no risk, there is no need to display information so as not to distract the driver.

  Therefore, by incorporating an arbitrary number of display areas, it is possible to help organize and rank information sent to the driver. Establishing new rules for the hierarchical organization of information not only helps to understand this information, but also assists the driver while driving, displaying only driving useful information and emergency alerts on the proximity plane To reduce the driver's mental burden.

  The head-up display device according to the present invention can be mounted on any kind of transparent surface capable of displaying information, such as a commercially available window glass surface or an electronic device having information to be projected.

Claims (8)

A head-up display device for displaying at least one image comprising:
A projection means (4) for generating a light beam carrying the displayed image;
A partially reflective screen (7) comprising at least one proximity display area and one remote display area arranged to display said image in a user field of view; and-said light beam from said projection means (4) An active element (5) arranged to receive and alternately transmit the light beam to the proximity display area and the remote display area
Equipped with a,
The proximity display area relates to an area of the partially reflective screen (7) comprising luminescent particles suitable for emission of visible wavelength radiation after absorption of the light beam;
The remote display region, and wherein the partially reflective der Rukoto to said light beam.   The active element (5) is linked to a light beam property management module (18) which can synchronize the power supply of the projection means (4) to the electrical polarization source of the active element (5). The head-up display device according to claim 1.   3. The head-up display device according to claim 1, wherein the active element (5) relates to an active light diffuser such as a PDLC film. The head-up display device according to any one of claims 1 to 3 , wherein the projection means (4) is a laser pico projector. In the active element (5) is a transmission type, characterized in that it is disposed between the projection means and (4) the display region, a head-up display according to any one of claims 1 4 apparatus. The active element (5) is of a reflective type and is arranged between a mirror and the projection means (4), the mirror being emitted from the active element on an optical path towards the display area. characterized in that it suitable for reflection, head-up display device according to any one of claims 1 to 4. A head-up display method for displaying at least one image comprising:
A step of generation by at least one projection means (4) of a light beam carrying an image to be displayed;
A step of displaying the image in a user field of view in at least one proximity display area and one remote display area arranged on a partially reflective screen (7), and said projection means (4) by an active element (5) look including the step of transmitting the light beam emitted alternately to the at least one proximity display area and the remote display area by,
The proximity display area relates to an area of the partially reflective screen (7) comprising luminescent particles suitable for emission of visible wavelength radiation after absorption of the light beam;
The method wherein the remote display area is partially reflective to the light beam . The method, wherein by active elements (5) that is linked to Ru management module (18), characterized in that it comprises the step of synchronizing the power supply of said projection means (4) to the electric polarization source of the active element (5) The head-up display method according to claim 7 .

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