Display device for a motor vehicle and test procedure for a display device of a motor vehicle

Abstract

Display device (1) for a motor vehicle with a display (3) for showing vehicle information, with a computing device (20, 60) for receiving vehicle data via a data bus (13), for evaluating the received vehicle data and for initiating an acoustic warning depending on the evaluation of the vehicle data, and with a storage unit (63) for storing audio signals to be output, wherein the stored audio signals are retrieved by the computing device (60) and processed in such a way that they are output to the loudspeaker (11), wherein the display device has a connection (31) to a loudspeaker (11) for outputting the acoustic warning, wherein the connection (31) to the loudspeaker (11) is connected to an input (35, 65) of an evaluation device (36) in such a way thatthat, depending on a signal applied to the terminal (31) of the loudspeaker (11), a malfunction or a function of the acoustic output is determined, and wherein an optical warning indicator (37) is provided to issue an optical warning in the event of a malfunction of the acoustic output.

Description

State of the art

[0001] The invention relates to a display device and a testing method for a display device according to the preamble of the main claim.

[0002] From DE 198 59 430 A1, a display device for a motor vehicle is already known in which a control unit is assigned a memory in which previously calculated image data is stored. The display device is intended for an instrument cluster in a motor vehicle and displays information relating to the current state of the vehicle or its surroundings, such as vehicle speed, engine speed, or interior and exterior temperature. The control unit receives information via a data input from which it generates instructions to display image data in the display.

[0003] Furthermore, it is known from the prior art to issue acoustic warnings to a driver of a vehicle, for example a lane departure warning or an acoustic feedback signal for a direction indicator.

[0004] From EP 0 909 114 A2, a car radio system with an amplifier is known that is designed to detect speaker faults. A fault signal from the amplifier is detected by a microprocessor, which sends an error message to the radio display.

[0005] From DE 100 20 992 A1, a method is known in a vehicle with a sensor device that serves to activate an audible warning tone from an acoustic signal generator to indicate a hazardous situation. The signal generator is checked for functionality by sensors.

[0006] From US patent 2012 / 0253821A1, a communication control unit for a vehicle is known which provides appropriate countermeasures in the event that a loudspeaker or microphone is defective.

[0007] A test device for a loudspeaker is known from US 2005 / 0 175 195 A1. Disclosure of the invention Advantages of the invention

[0008] The display device according to the invention, with the features of the main claim, has the advantage that, in the case of an acoustic warning indicator, a visual feedback is provided to the driver when the acoustic warning indicator has failed. Acoustic warnings in the vehicle are specifically designed so that the driver does not have to look at the display device to perceive the warning. In particular, warnings are also provided when a fault or a hazard of particular severity occurs, so that the driver is warned not only via a visual perception channel but also via the additional acoustic warning. If the corresponding acoustic warning fails, a driver may rely on any acoustic warning that may have been generated and, if it is absent, mistakenly assume that there is no danger.Because the driver receives a visual warning in the event of a failure of the acoustic warning, there is a possibility that the driver will pay more attention to a visual warning indicator in the vehicle in such a case, or that the driver will observe the vehicle's surroundings more closely and not rely on the potentially expected acoustic warning. This increases safety in the vehicle. The advantages of the invention are achieved in particular by determining whether a malfunction or function of the acoustic output is present depending on a signal applied to a speaker connection of a display device, and by providing a visual warning indicator to issue a visual warning in the event of a malfunction of the acoustic output.

[0009] Linking an acoustic warning output to the display unit is advantageous because the display unit typically already processes vehicle information for visual display, thus enabling the simple generation of an acoustic warning. Furthermore, according to the invention, it is also easy to verify whether the acoustic warning is being issued correctly.

[0010] The measures listed in the dependent claims enable advantageous further developments and improvements of the display device specified in the main claim. It is particularly advantageous to provide an output circuit that rectifies the signal applied to the loudspeaker and integrates it with a capacitor. This allows the evaluation of the loudspeaker signal to be reduced to a comparison with a fixed threshold value, thus simplifying the evaluation process.

[0011] According to the invention, a storage unit is provided for storing audio signals to be output. This simplifies the output of acoustic warnings and also allows a test signal to be stored in the storage unit to determine whether the acoustic output device is functioning correctly. By using a stored control signal for a test, the execution of a test is simplified, as a fixed, predefined signal can be easily retrieved from memory.

[0012] Furthermore, it is advantageous to control an amplifier device for generating an output signal at the loudspeaker connection from a computer. This allows for easy testing of the functionality of the acoustic output via the computer.

[0013] Furthermore, it is advantageous to divide the computing unit into a first and a second computing unit. The first computing unit can easily evaluate a vehicle data bus and determine corresponding warning information. Since the acoustic output is handled by a second computing unit, an acoustic warning can also be issued, for example, if there is a disruption in the data bus connection or a processing error in the first computing unit. In particular, it is advantageous that an evaluation unit, which verifies the functionality of the acoustic output, is located in the second computing unit.

[0014] Because the same unit that receives a request to issue an acoustic warning message also monitors the correct output of the warning and generates a corresponding warning message indicating the malfunction in case of a malfunction, only this unit needs to be considered with regard to its hardware and software when assessing the reliability of the acoustic warning system.

[0015] Corresponding advantages arise for a test method according to the invention for a display device of a motor vehicle.

[0016] A particular advantage here is that, during a function test of the acoustic output, the speaker connection is supplied with a signal which, when passed on to the speaker, causes it to emit an audio signal in a frequency range inaudible to humans. This allows a test procedure to be carried out without disturbing the driver. Specifically, it makes it possible to send a sufficient signal amplitude to the speaker connection without distracting the driver by generating a loud, audible signal.

[0017] It is also advantageous that, in the event of a malfunction of an acoustic output, at least one vehicle system that relies heavily on acoustic feedback is deactivated. This prevents a driver from relying on an activated system, the activation of which may also be indicated, and thus committing a driving error because they are not acoustically warned of a danger to the vehicle. Brief description of the drawings

[0018] Examples of the invention are shown in the drawing and explained in more detail in the following description. Fig. 1 a schematic view of a display device according to the invention in a motor vehicle, Fig. 2 a first embodiment of a display device according to the invention in a motor vehicle, Fig. 3 a detail of an output circuit according to the invention for a display device according to the invention, Fig. 4 an example of an amplifier unit for an acoustic output of a display device according to the invention, Fig. 5 a second embodiment of a display device according to the invention for a motor vehicle, Fig. 6 a test method according to the invention for a display device of a motor vehicle. Embodiments of the invention

[0019] In the Fig. Figure 1 shows an embodiment of a display device 1 according to the invention in a motor vehicle 2. The display device 1 is arranged, in particular, in an instrument panel of the motor vehicle 2. It is specifically positioned in front of the driver of the vehicle 2 in the instrument panel. In a further embodiment, the display device 1 can also be arranged in a center console of the vehicle 2.

[0020] The display unit 1 has a display area 3, which is, for example, a liquid crystal display. The display area 3 includes, for example, a pointer display 4 for representing a measured value by means of a pointer 5 against a scale 6, which is displayed as images in the display area 3. Furthermore, text outputs or symbols can also be displayed in display fields 7. The display area 3 is used in particular to display vehicle information, such as vehicle speed, engine speed, or vehicle parameters such as fuel level or coolant temperature. Warning information, such as the distance to an obstacle, a lane departure warning, or a vehicle system failure, can also be displayed in the display area 3.In particular, information about a direction indicator can also be provided in display area 3, for example by displaying an arrow symbol.

[0021] In a further embodiment, warning lights 8 can also be provided, which are activated in the event of vehicle malfunctions. The activation of a warning light is associated with a vehicle malfunction either by a symbol located on the warning light or next to it. In an optional embodiment, a control element 9 can also be provided, with which the driver can make inputs to control the display device.

[0022] Furthermore, the display device 1 is connected to a loudspeaker 11 via a connection 10. In a first embodiment, the loudspeaker 11 can be arranged in a component of the display device 1, for example, it can be located on a surface in the Fig. The display unit 1 is mounted on a circuit board (not shown), which also carries the control electronics of the display unit 1. In a further embodiment, it can also be provided in the instrument panel adjacent to the display unit 1. In a further embodiment, the display unit 1 can also be connected to a radio system in the motor vehicle 2, so that acoustic outputs initiated by the display unit 1 are transmitted via the car radio of the motor vehicle 2.

[0023] In particular, the loudspeaker 11 is activated to emit a warning signal when the display device 1 has detected a danger to the vehicle 2 or a critical condition of the vehicle 2.

[0024] To detect hazards to the vehicle or vehicle conditions, the display unit 1 is connected to a vehicle data bus 13 via a data bus connection 12. The vehicle data bus 13 is preferably a CAN bus. However, alternatively or additionally, other data buses, such as a MOST bus or a LIN bus, may be provided. The display unit 1 is connected via the data bus 13 to control units 14, 15 in the vehicle that control vehicle functions or monitor the vehicle environment or vehicle functions. These can be, for example, a brake control unit, an environmental monitoring control unit such as a distance sensor control unit, or an engine control unit. The information from these control units is transmitted to the display unit 1 via the data bus 13 and evaluated in the display unit 1.For example, the distance to obstacles in the vehicle's vicinity, measured by the vehicle's distance sensors 2, can be evaluated by the vehicle control unit 15 and reported to the display unit 1. The display unit 1 then shows, for example, a message indicating the critical distance of the vehicle in text field 7. Furthermore, an acoustic signal, such as a continuous or intermittent tone, can be emitted to the driver of the vehicle via the loudspeaker 11.

[0025] The Fig. Figure 2 shows an embodiment of a display device according to the invention. A computing unit 20 of the display device is connected to the data bus 13 via a data bus connection 21. The computing unit 20 has an evaluation unit 22, which evaluates the vehicle data received via the vehicle data bus and compares it with a reference value stored in a memory 23. If it is detected that one of the vehicle data values, for example a distance value or a vehicle temperature, exceeds a critical value or that a specific vehicle function, such as a turn signal or a hazard warning indicator, has been activated, the evaluation unit 22 initiates the output of visual information via the display area 3. For this purpose, a graphics processor 24 is preferably controlled, which drives the display area 3.

[0026] If an acoustic output is provided as an alternative or supplement, the evaluation unit 22 initiates the acoustic output by sending a control command to an amplifier unit 25. The amplifier unit 25 generates a control signal for the loudspeaker 11. This control signal excites the loudspeaker 11, producing an acoustic signal audible to the driver. The acoustic signal can be a warning tone, a modulated warning signal, or a voice output. The loudspeaker 11 is connected to outputs of the amplifier unit 25 via a first terminal 31 and a second terminal 32. An electrical terminal 33 is provided at the first terminal 31, through which an output signal sent from the amplifier unit 25 to the loudspeaker 11 is tapped. The output signal is preferably routed via a coupling unit 34 to an input 35 of the computer unit 20.The computing unit 20 has an evaluation unit 36 ​​that evaluates the input signal. Preferably, the input 35 has an analog-to-digital converter so that the input signal can be digitally evaluated by the computing unit 20.

[0027] Preferably, the signal is smoothed and integrated by the output unit 34. The evaluation unit 36 ​​then compares the integrated and smoothed signal with a predefined threshold. If the threshold is exceeded, an acoustic output is generated, and the functionality of the acoustic output unit is confirmed. However, if an error occurs at any point in the acoustic output, no acoustic output signal is present. In this case, the threshold is not reached. If the threshold is not reached, a malfunction of the acoustic output is detected. In this case, in a first embodiment, the evaluation unit 36 ​​activates a warning lamp 37, which is preferably located in the display unit 1 or at another location in the vehicle. In a further embodiment, an indication can alternatively or additionally be displayed in the display area 3.

[0028] In another embodiment, the alternating voltage signal normally used to control the loudspeaker 11 is fed via connection 33 to input 35 of the evaluation unit and evaluated there. On the one hand, it is possible to evaluate the amplitude of the signal. Furthermore, in another embodiment, it is also possible to compare the waveform of the tapped electronic signal with a predefined signal waveform in order to verify the correctness of the acoustic output with respect to the signal shape and thus, for example, to monitor the intelligibility of speech output with an expected signal shape corresponding to the speech signal.

[0029] In the Fig. Figure 3 shows an embodiment of the output unit 34. The signal supplied via connection 33 and tapped from the connection of the loudspeaker 11 is first routed through an output capacitor 40. The signal is then rectified by a first diode 41. A second diode 46 is connected in reverse bias with respect to ground 43 between the output capacitor 40 and the first diode 41. The signal is integrated via a low-pass filter circuit connected to the first diode 41, i.e., a resistor 42 and a capacitor 44 connected to ground 43. An additional resistor 45 can also be connected to ground. Preferably, the amplifier unit 25 is connected to corresponding outputs of the computing device via both a data line 51 and a control line 52. The data line 51 can, for example, be an analog data line.Preferably, filter circuits can also be provided between the amplifier device 25. In a preferred embodiment, the data line 51 can also be implemented as a digital data connection. For example, the data connection 51 can be an I. 2 S-data connection must be in operation.

[0030] The control line 52 serves to control the amplification, in particular the volume. Preferably, the control line is configured as an I 2The amplifier unit 25 includes a decoding unit 53 for decoding the received audio signals. Furthermore, the amplifier unit includes an evaluation unit 54 for evaluating the received control signals. An amplifier circuit 55 is also provided, in which the audio control signals determined via the decoding unit 53 are amplified such that an alternating voltage can be applied to the outputs 31, 32, thereby driving a connected loudspeaker to produce an audible audio signal in the vehicle. In another embodiment, it is also possible to use a digital loudspeaker.

[0031] In the Fig. Figure 5 shows a further embodiment of a display device according to the invention. A computing unit 60 comprises a first computing unit 61 and a second computing unit 62. The first computing unit 61 processes the vehicle data received from the data bus 13 and evaluates it to determine whether a warning message needs to be displayed. The display area 3 is controlled accordingly. The second computing unit 62 is controlled by the first computing unit 61. The second computing unit 62 handles the output of acoustic information. For this purpose, the second computing unit 62 is connected to a storage unit 63. Pre-calculated control signals for acoustic output are stored in the storage unit 63. The storage unit 63 is preferably arranged on a circuit board of the display device.The second processing unit 62 reads corresponding acoustic control signals from the storage unit 63 based on the control commands received from the first processing unit 61 and forwards them to the amplifier unit 25. The amplifier unit 25 controls the loudspeaker 11 accordingly. A signal tapped from a terminal 31 of the loudspeaker 11 is forwarded via the output unit 34 to an input 65 of the processing unit 60. Preferably, the second processing unit 62 evaluates the received signal and checks whether the acoustic output unit is functioning. In the event of a malfunction, a notification of the malfunction is displayed on the display area 3 or via a warning indicator 37.

[0032] In the Fig.Figure 6 shows an embodiment of a test sequence according to the invention. The test sequence is initiated with an initialization step 70. A check can be performed, for example, when the vehicle's engine is started. Furthermore, it is also possible for a check to be performed at predetermined time intervals, even while driving. Additionally, a check can be performed when a particularly relevant vehicle system is activated, such as a distance indicator. With the distance indicator, a driver will typically observe the vehicle's surroundings and therefore take their eyes off the display. They rely in particular on the acoustic feedback of a distance warning. Thus, when a distance warning indicator is activated, for example, when reverse gear is engaged, the acoustic output can also be checked.

[0033] For testing purposes, in a measurement and verification step 71, the display unit's computing device outputs a test signal via an amplifier unit to a loudspeaker of the display unit's acoustic output. In a first embodiment, this can be an audible signal, for example, a warning tone used to alert the driver. In a further embodiment, the volume of this warning tone can be reduced during the functional test compared to the conventional output, so that the tone is barely audible, but the signal is still easily interpretable. In a further embodiment, a warning tone can be selected whose frequency lies in a frequency range that is inaudible or poorly audible to humans. For example, a suitable frequency in the range of 25 kHz to 50 kHz is selected.

[0034] In a subsequent test step 72, it is checked whether a signal is detected by the computer device via the signal tap from the loudspeaker connection. If this is the case, the device is functioning and the process branches to a final step 73.

[0035] If no signal or an insufficient signal is detected, in one embodiment the process can first branch to an adjustment step 74. In adjustment step 74, a counter is incremented to indicate that adjustment step 74 has already been reached. Furthermore, the signal amplitude is increased. The measurement step 71 is then repeated. If the subsequent test step determines that no signal can still be detected, the process branches to an output step 75. In another embodiment, output step 75 can also be reached directly from test step 72 without adjustment step 74.

[0036] In output step 75, a visual message is sent to the driver indicating that an acoustic warning function is not working. This can be done, for example, by activating a warning light or, alternatively or additionally, by displaying a text message on a screen of the display device 1. In a further optional deactivation step 76, a vehicle function can be deactivated, for example, a lane departure warning. This is preferably indicated to the driver by an additional deactivation message from the driver assistance system via a visual display. The method according to the invention is then terminated by a final step 77.

Claims

[1] Display device (1) for a motor vehicle comprising a display (3) for showing vehicle information, a computing device (20, 60) for receiving vehicle data via a data bus (13), for evaluating the received vehicle data and for initiating an acoustic warning depending on the evaluation of the vehicle data, and a storage unit (63) for storing audio signals to be output, wherein the stored audio signals are retrieved by the computing device (60) and processed in such a way that they are output to the loudspeaker (11), wherein the display device has a connection (31) to a loudspeaker (11) for outputting the acoustic warning, wherein the connection (31) to the loudspeaker (11) is connected to an input (35, 65) of an evaluation device (36) in such a way thatthat, depending on a signal applied to the terminal (31) of the loudspeaker (11), a malfunction or a function of the acoustic output is determined, and wherein an optical warning indicator (37) is provided to issue an optical warning in the event of a malfunction of the acoustic output. [2] Display device according to claim 1, characterized by a coupling circuit (34) with at least one diode (41) for rectifying the signal applied to the terminal of the loudspeaker and with at least one low-pass filter (42, 43) for integrating the signal to provide a DC voltage level at the input (35) of the evaluation device. [3] Display device according to any one of the preceding claims, characterized by an amplifier device (25) for generating an output signal at the connection (31) of the loudspeaker (11), wherein the amplifier device is connected via a data bus (51), in particular an I 2S data bus, which is controlled by the computing unit (20, 60). [4] Display device according to claim 3, characterized by , that the computing device (60) has a first computing unit (61) and a second computing unit (62), that the first computing unit (61) has at least one interface to a vehicle data bus (13), evaluates the received vehicle data and, depending on the evaluation, causes an audio output by the second computing unit (62), and that, depending on this cause, the second computing unit (62) causes the amplifier device (25) to output a predetermined audio signal to the loudspeaker (11). [5] Display device according to claim 4, wherein the evaluation device is connected to the second computing unit (62) and the optical warning indicator (37) is controlled by the second computing unit (62). [6] Test method for a display device (1) of a motor vehicle with a display (3) for showing vehicle information, wherein a computing device (20, 60) receives and evaluates vehicle data via a data bus (13) and initiates an acoustic warning depending on the evaluation of the vehicle data, wherein the acoustic warning is generated by controlling a loudspeaker (11) via a connection of the display device, wherein the stored audio signals are retrieved by the computing device (60) from a storage unit (63) for storing audio signals to be output and processed in such a way that they are output to the loudspeaker (11), wherein a malfunction or a function of the acoustic output is determined by an evaluation device (36) depending on a signal present at the connection of the loudspeaker (11).and that in the event of a malfunction of the acoustic output, a visual indication is displayed. [7] Test method according to claim 6, characterized by , that in a test operation, a control signal is applied from the display device to the connection of the loudspeaker (11), which corresponds to an audio signal in a frequency range inaudible to humans. [8] Test method according to one of claims 6-7, characterized by , that in the event of a detected malfunction of the acoustic output, at least one vehicle system is deactivated.

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