Method for operating a head-up display device for a motor vehicle with color value adjustment, head-up display device and motor vehicle
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- VALEO SCHALTER & SENSOREN GMBH
- Filing Date
- 2016-03-21
- Publication Date
- 2026-07-23
AI Technical Summary
Existing head-up display devices for motor vehicles are not operated simply and reliably, particularly in adjusting color values to ensure consistent perception across varying lighting conditions and vehicle interior elements.
A method and device that adjusts pixel color values in a head-up display using a control device to determine and apply corrected drive signals based on predetermined conditions, such as lighting and vehicle interior colors, ensuring consistent color representation without structural changes.
Enables simple and reliable adjustment of color values, particularly white tones, to match vehicle interior elements, reducing perceptual differences under varying lighting conditions, and optimizing energy consumption.
Smart Images
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Abstract
Description
[0001] The present invention relates to a method for operating a head-up display device for a motor vehicle, in which an image is generated by means of an imaging unit and the image is projected onto a display element, which has a semi-transparent mirror surface, to provide a virtual display for generating the image by means of a control device using image data which describe an assignment of color values to respective pixels of the imaging unit, a control value is determined for each pixel and each of the pixels is controlled with the specific control value. Furthermore, the present invention relates to a head-up display device for an automobile. Finally, the present invention relates to a motor vehicle.
[0002] Various configurations of display devices for motor vehicles are known from the prior art. In the present case, interest is directed in particular to head-up display devices or head-up displays. Such a head-up display device usually includes an imaging unit for providing an image. Furthermore, the display device includes an optical device, which can include, for example, one or more mirrors. The image generated by the imaging unit can be projected onto a display element with the optical device. In particular, the display element can have a semi-transparent mirror surface. This semi-transparent mirror surface can be provided, for example, by an area of the windshield of the motor vehicle. Furthermore, display devices are known which have a separate display element. Such display elements can also be referred to as combiners, combiner mirrors or combiner discs. A virtual image can thus be provided from the superimposition of the information projected onto the display element, which is reflected by the latter, with information shining through the display element from an environment located behind the display element.
[0003] The imaging unit of the head-up display device can have a screen that has a plurality of pixels. These pixels can be controlled independently of one another with a control device, so that a desired color value is output with the respective pixels. The screen can, for example, be in the form of a liquid crystal display and have a number of thin-film transistors (TFT—Thin Film Transistor). Furthermore, the imaging unit can have background lighting, which is provided by at least one light source.
[0004] In this context, WO 2015 / 048911 A1 describes a method for correcting a desired color of a pixel of an optically transparent display. Here, a color of the background is determined and assigned to the respective pixels of the display. Depending on the color of the background and a predicted perception by a viewer, the display can then be controlled accordingly.
[0005] It is the object of the present invention to provide a solution as to how a head-up display device of the type mentioned at the outset can be operated more simply and reliably.
[0006] According to the invention, this object is achieved by a method, by a head-up display device and by a motor vehicle having the features according to the respective independent claims. Advantageous developments of the present invention are the subject matter of the dependent claims.
[0007] In one configuration of a method for operating a head-up display device for a motor vehicle, an image is generated by means of an imaging unit and the image is projected onto a display element, which has a semitransparent mirror surface, to provide a virtual display. In particular, a control signal is determined for each of the pixels and each of the pixels is preferably controlled with the determined control signal to generate the image using a control device based on image data which describe an assignment of color values to respective pixels of the imaging unit. Those pixels which are assigned a predetermined color value are preferably selected by means of the control device as a function of a predetermined condition. Furthermore, a corrected drive signal is preferably determined for the selected pixels and the selected pixels are each driven with the corrected drive signal.
[0008] A method according to the invention serves to operate a head-up display device for a motor vehicle. In this case, an image is generated by means of an imaging unit and the image is projected onto a display element, which has a semi-transparent mirror surface, in order to provide a virtual display. To generate the image, a control device uses image data describing an assignment of color values to respective pixels of the imaging unit to determine a control signal for each of the pixels and to control each of the pixels with the specific control signal. Furthermore, depending on a predetermined condition, the control device selects those pixels to which a predetermined color value is assigned, a corrected drive signal is determined for the selected pixels and the selected pixels are each driven with the corrected drive signal.
[0009] A head-up display device or a head-up display of a motor vehicle is to be operated with the method. The head-up display device includes the imaging unit, by means of which an image can be generated. This image can then be projected onto the display element which has the semi-transparent mirror surface. The display element can be, for example, the windshield of the motor vehicle or a part thereof. The display element can also be formed by a so-called combiner. The virtual display can be provided on the display element. This results from a superimposition of the image projected onto the display element, which is reflected by it, with information behind the display element shining through the display element.
[0010] The imaging unit can include a screen, for example, which in turn has a plurality of pixels. The screen can in particular be a liquid crystal display (LCD—Liquid Crystal Display). Such a screen comprises a number of segments which are assigned to the respective pixels. The respective pixels can be controlled by a drive signal. The control signal can be an electrical voltage, for example. The alignment of the liquid crystals can then be controlled with the aid of the control signal. This changes the permeability of the liquid crystals for polarized light, which is generated, for example, with a backlight and a corresponding polarization filter. Each picture element or each pixel can be divided into three sub-pixels which have color filters for the colors red, green and blue. A color can then be generated for each pixel by controlling the liquid crystals in the respective sub-pixel. To control the respective pixels, the control device is provided, which can determine the respective control signals for the pixels or the sub-pixels on the basis of predetermined image data. The image data describe the color values of the respective pixels.
[0011] According to the invention, it is now provided that the control device first checks whether a predetermined condition is met. If the predetermined condition is met, the control device is used to select those pixels from all the pixels of the imaging unit which are associated with a predetermined color value. A corrected drive signal is then determined for the selected pixels and the selected pixels are each driven with the corrected drive signal. A shift in the direction of a specified color value can thus be achieved with the aid of the control device for the predetermined color or the predetermined color value. Provision can also be made for the respective control signals for the remaining pixels to be adapted. This enables a simple adjustment of the color values that are provided with the imaging unit and which are then projected onto the display element. Thus, no structural changes to the heads-up display device are required to accommodate the virtual display.
[0012] Those pixels which are assigned a white color value are preferably selected by means of the control device and controlled with the corrected control signal. In other words, the representation of the color white on the imaging unit and thus on the display element is changed by the corrected control signal. The display of the color value white with the selected pixels can usually be achieved in that the respective sub-pixels have maximum light transmission. The light transmission of at least one of the sub-pixels can be reduced by the corrected control signal, so that a predetermined or specified white color value results overall. In this way, the representation of the color white can be adjusted in a simple manner.
[0013] In one embodiment, the corrected drive signal is determined as a function of a viewer's perception of the predetermined color value of the virtual display. The color white may appear different to a viewer of the virtual display. For example, the observer of the virtual display can perceive it as bluish or yellowish, depending on the lighting conditions in the area or a design of the imaging unit. The corrected control signal can be used to ensure that the predetermined color value, and in particular the color value, is displayed in white as desired.
[0014] Furthermore, it is advantageous if the corrected control signal is determined as a function of a color value of a component of the motor vehicle. A corrected color value can be output by the selected pixels by the corrected control signal. This corrected color value can in particular be determined in such a way that it corresponds to a corresponding color value of at least one component in the interior of the motor vehicle. The component can be a control element or a display element in the interior of the motor vehicle. For example, if the controls in the interior have a predetermined color value, the corrected control signal can be determined in such a way that the corrected color value corresponds to the color value of the control element. The color value can also be adapted to a color of the illuminated instruments in the interior of the motor vehicle. Thus, the viewer cannot see any differences between the color tones, in particular the white tones, of the virtual display and those of the controls.
[0015] It is also advantageous if the imaging unit has a screen and at least one light source for backlighting the screen and the corrected control signal is determined as a function of a color value of a light emitted by the at least one light source. The background lighting can include at least one light-emitting diode, for example, which emits light in the white wavelength range. The color value of the light from the at least one light-emitting diode can be determined or is known. In this case, a light-emitting diode can already be used as the background lighting, the color value of which has the smallest possible difference from the desired color value. Because the corrected control signal is determined as a function of the color value of the light source or the light-emitting diode, the corrected color value can be reliably provided.
[0016] In a further embodiment, a color shift of the light emitted by the at least one light source is determined by the screen and the corrected control signal is determined as a function of the color shift. The screen can have appropriate polarization filters and / or diffusers, which cause a color shift in the light provided by the backlight. It can thus be determined how the color value of the light from the backlight changes as it penetrates through the screen. This enables the corrected drive signal to be reliably determined.
[0017] Brightness in the area surrounding the motor vehicle is preferably detected and the predetermined condition includes that the brightness falls below a predetermined threshold value. In head-up displays in particular, the perception of white level is very dependent on the background superimposed on the projected image. In bright daylight conditions, the white color value will always be perceived differently due to the changing environment and light conditions. If the brightness falls below a predetermined threshold, the background changes only slightly. In addition, the contrast between the white color value and the dark or black background is greater. The brightness in the vicinity of the motor vehicle can now be determined with the aid of a corresponding sensor. If the brightness falls below the predetermined threshold value, the color value can be adjusted. The color value can thus be adjusted if this is also perceived by the viewer of the virtual display.
[0018] In another embodiment, the at least one predetermined condition includes that a luminance of the virtual display is less than a predetermined threshold. As described above, the light transmittance of the respective sub-pixel can be adjusted by the corrected drive signal. This leads to a loss of brightness or luminance of the virtual image. This loss can be compensated for by increasing the electrical current of the backlighting LEDs. However, this in turn can lead to heating of the screen or the imaging unit. Provision can also be made for the brightness of the background lighting to be adjusted as a function of the brightness in the area surrounding the motor vehicle. This has the advantage that the electrical current required to operate the backlight is significantly lower, which means that the heating of the screen is also reduced. For example, the predetermined limit for the luminance of the virtual display can be 7000 cd / m 2 be. Thus, safe and reliable operation of the head-up display device can be ensured.
[0019] In a further embodiment, the generated image is projected onto the display element by means of an optical device which has at least one mirror. This makes it possible to arrange the imaging device inside a dashboard of the motor vehicle. The generated image can then be deflected with the optical device and projected onto the display element. In this way, a space-saving arrangement can be achieved.
[0020] A head-up display device according to the invention for a motor vehicle is designed to carry out a method according to the invention.
[0021] A motor vehicle according to the invention comprises a head-up display device according to the invention. The motor vehicle is designed in particular as a passenger car.
[0022] The preferred embodiments presented with reference to the method according to the invention and their advantages apply correspondingly to the head-up display device according to the invention and to the motor vehicle according to the invention.
[0023] Further features of the invention result from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description, as well as the features and feature combinations mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the combination specified, but also in other combinations or on their own, without the frame to abandon the invention. The invention is therefore also to be considered to include and disclose embodiments that are not explicitly shown and explained in the figures, but that result from the explained embodiments and can be generated by separate combinations of features. Versions and combinations of features are also to be regarded as disclosed which therefore do not have all the features of an originally formulated independent claim. Furthermore, embodiments and combinations of features, in particular through the embodiments presented above, are to be regarded as disclosed which go beyond or deviate from the combinations of features presented in the back references of the claims.
[0024] The invention will now be explained in more detail using preferred exemplary embodiments and with reference to the accompanying drawings.
[0025] show:
[0026] figure 1 is a sectional view of a motor vehicle having a head-up display device according to an embodiment of the present invention;
[0027] figure 2 color values provided by light sources for backlighting a screen of the head-up display device and desired color values for the presentation of a virtual display; and
[0028] figure 3 shows a schematic flow chart for operating the head-up display device according to an embodiment of the invention.
[0029] In the figures, identical and functionally identical elements are provided with the same reference symbols.
[0030] figure 1 shows a detail representation of a motor vehicle 1 according to an embodiment of the present invention. The car 1 is presently designed as a passenger car. The car 1 includes a head-up display device 2 . The heads up display device 2 includes an imaging unit 3 , by means of which an image can be provided. The imaging unit 3 may have a screen illuminated with a backlight.
[0031] The heads up display device 2 further comprises an optics device 5 showing a mirror 6 includes. That from the imaging unit 3 created image or by the imaging unit 3 emitted light hits the mirror first 6 and then becomes a display element 7 projected. The imaging unit 3 and the optics 5 are present within a dashboard of the motor vehicle 1 arranged. The arrangement of the individual components of the head-up display device 2 is to be understood purely as an example in the present case.
[0032] The display element 7 has a semi-transparent mirror surface. Present is the display element 7 formed by a combiner or a combiner disk. The display element can be made of glass or plastic, for example. The display element 7 is present with a holding element 8held. The image with the imaging unit 3 is generated is by means of the optical device 5 on the display element 7 projected. Furthermore, the light or the image on the display element 7 is projected to the eyes 9 a driver of the motor vehicle 1 reflected. Thus, this display is superimposed on the light coming from an environment 11 of the motor vehicle 1 to the eyes 9 of the driver arrives, with the light falling on the display element 7 is projected. For the driver of the motor vehicle 1 the result is a virtual display 10 or a virtual image.
[0033] The heads up display device 2 further comprises a control device 4 . With the help of the controller 4 can the imaging unit 3 be controlled. The imaging unit 3 can comprise the screen, which in turn is divided into several pixels. Each of the image points or each pixel can in turn comprise three sub-pixels which are assigned to the colors red, green and blue. The screen can be designed in particular as a liquid crystal display. With the controller 4 a control signal is determined for each pixel, which is used to set the light transmittance of the respective sub-pixel. A respective color value of the pixels of the screen can thus be set. In addition, the imaging unit includes 3 a backlight, which can include at least one light source or at least one light-emitting diode. The car 1 further includes a sensor 12 , with which a brightness in the area 11 of the motor vehicle 1 can be determined. This sensor 12 is for data transmission with the control device 4 tied together. Corresponding data lines are not shown here for the sake of clarity.
[0034] Here are the color values of the virtual display 10 be adjusted. In particular, the white color values of the virtual display 10 adjusted to desired white color values. These desired white color values 13 , 13‘ are in figure 2, which shows a CIE color triangle indicated by the x and y axes. In this coordinate system are two different white color values 13 and 13‘ as well as their respective tolerance range 14 and 14‘ shown. Furthermore, areas 15 , 16 , 17 shown for respective color values that can be achieved by different LEDs for backlighting. A color shift in the light emitted by the light-emitting diodes is also taken into account by the screen. Especially in the event that the desired white color value 13‘ is to be achieved, the color value provided by the light-emitting diodes must be adjusted.
[0035] To adjust the color value are using the control device 4 those pixels of the screen are selected with which the color value white is to be represented. This can be done on the basis of image data, which is the image created with the imaging unit 3 to be provided describe. A corrected control signal is now used in comparison to a control signal which is usually used and is used to control pixels for outputting the white color. In particular, the light transmittance of the respective sub-pixel is adjusted. This allows the color value for the color white to be shifted or to the desired white color value 13 , 13‘ be adjusted. In particular, the corrected control signal is determined in such a way that the white color value corresponds to a white color value of operating elements or illuminated displays in the interior of the motor vehicle 1 is equivalent to. Thus, the driver of the motor vehicle 1 no differences in the white tones of the virtual display 10 and recognize the controls.
[0036] figure 3 shows a schematic flow chart of a method for operating the head-up display device 2. In a step S1, a luminous flux or brightness in the environment 11 of the motor vehicle 1 with the help of the sensor 12 measured. The sensor signals associated with the sensor 12 are provided to the controller 4 transfer. With the help of the controller 4 can be checked in a step S2 whether the brightness in the area 11 is lower than a predetermined threshold. If this is the case, the method is continued in a step S3. Here, the head-up display device 2 switched to night mode. In a step S4, the adjusted control signal for the pixels, in particular the pixels with which a white color value is to be output, is then determined with the aid of the control device. When the brightness around 11 is greater than the predetermined threshold value, the method is continued in a step S5. At this time, the head-up display device 2 switched to day mode. In a further step S6, the adaptation of the color values is deactivated.
[0037] In the present case, it is taken into account that the imaging unit 3 can warm up by adjusting the color values. This is due to the fact that the light transmittance of the respective sub-pixel is reduced during color adjustment. Therefore, the color value adjustment is performed only in dark ambient conditions where the backlight brightness is reduced. It is further taken into account that in dark ambient conditions the differences between the white tones of the virtual display 10 and the white tones of the controls can be perceived more clearly. Thus, the white color values are only adjusted if the driver can perceive a difference between the white color values. In daylight conditions, the color value is not adjusted because the white color value is perceived by the background in the environment 11 varies and the driver sees the difference between the white color values in the virtual display 10 and can hardly perceive the controls. QUOTES INCLUDED IN DESCRIPTION
[0038] This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Patent Literature Cited
[0039] WO 2015 / 048911 A1
[0004]
Claims
[1] Method for operating a head-up indicator device ( 2 ) for a motor vehicle ( 1 ), in which an imaging unit ( 3 ) an image is generated and the image is used to provide a virtual display ( 10 ) on a display element ( 7 ), which has a semi-transparent mirror surface, is projected, whereby the image is generated by means of a control device ( 4 ) based on image data, which assigns color values to respective pixels of the imaging unit ( 3 ) describe a process in which a control signal is determined for each of the pixels and each of the pixels is controlled with the determined control signal, characterized by that by means of the control device ( 4) depending on at least one predetermined condition, those pixels are selected to which a predetermined color value is assigned, a corrected control signal is determined for the selected pixels, and the selected pixels are each controlled with the corrected control signal. [2] Method according to claim 1, characterized by that by means of the control device ( 4 ) those pixels are selected and controlled with the corrected control signal to which a white color value is assigned. [3] Method according to claim 1 or 2, characterized by that the corrected control signal is determined depending on a viewer's perception of the predetermining color value of the virtual display. [4] Method according to any one of the preceding claims, characterized bythat the corrected control signal depends on a color value of a component in the interior of the motor vehicle ( 1 ) is determined. [5] Method according to any one of the preceding claims, characterized by that the imaging unit ( 3 ) has a screen and at least one light source for backlighting the screen, and the corrected control signal is determined as a function of a color value of a light emitted by the at least one light source. [6] Method according to claim 5, characterized by that a color shift of the light emitted by the at least one light source is determined by the screen and the corrected control signal is determined depending on the color shift. [7] Method according to any one of the preceding claims, characterized by that brightness in an environment ( 11 ) of the motor vehicle ( 1) is detected and includes at least one predetermined condition that the brightness exceeds a predetermined threshold. [8] Method according to any one of the preceding claims, characterized by that it includes at least one predetermined condition, namely that the luminance of the virtual display is less than a predetermined limit. [9] Method according to any one of the preceding claims, characterized by that the generated image is produced by means of an optical device ( 5 ), which at least has a mirror ( 6 ) has, on the display element ( 7 ) is projected. [10] Head-up indicator device ( 2 ) for a motor vehicle ( 1 ), which is designed to carry out a method according to any of the preceding claims. [11] motor vehicle ( 1 ) with a head-up indicator device ( 2 ) according to claim 10.