JP7604857B2 - Vehicle display device - Google Patents

Description

The present invention relates to a display device for a vehicle.

As a conventional vehicle display device, for example, the configuration described in Patent Document 1 is known. The vehicle display device shown in Patent Document 1 is a head-up display (1) that operates by receiving power from a battery (45). The power supply unit (22) is a transformer that transforms the voltage applied from the battery (45) to the head-up display (1) and then supplies power to each component that constitutes the head-up display (1).

JP 2014-144743 A

However, with the configuration described in Patent Document 1, if an abnormality occurs in the external power supply that applies voltage to the head-up display, the abnormal voltage may be applied to each component that makes up the head-up display, which may lead to device failure.

Therefore, the object of the present invention is to provide a vehicle display device that addresses the above-mentioned issues and has improved resistance to power supply abnormalities.

In order to achieve the above object, the present invention provides a display device for a vehicle, comprising:
A vehicle display device that is mounted on a vehicle and displays vehicle information,
a display for displaying the vehicle information;
a processor for controlling the display;
a first power supply that transforms an externally applied power supply voltage into a first voltage and supplies power to the processor;
a second power source that transforms the power source voltage to a second voltage;
Operates based on the second voltage;
operating the first power supply normally when the first voltage is less than a first threshold voltage;
a voltage determination unit that stops the first power supply when the first voltage is equal to or higher than a first threshold voltage.
The processor outputs a voltage abnormality occurrence signal to an external device when the first voltage is lower than the first threshold voltage and equal to or higher than the second threshold voltage .

1 is a diagram showing a configuration of a head-up display 1 according to an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a HUD 1 and a meter 2.

Below, as an example of a vehicle display device according to the present disclosure, a head-up display (HUD) 1 mounted on a vehicle C will be described as an embodiment and a modified example with reference to the accompanying drawings in the following order. Note that the directions F, B, L, R, U, and D shown in the drawings correspond to the front, rear, left, right, up, and down directions of the vehicle C, respectively. The left-right direction may be referred to as direction X, the up-down direction as direction Y, and the front-rear direction as direction Z.

[First embodiment]
1-1. Description of the configuration 1-2. Description of the behavior [Modification]

[First embodiment]
<1-1. Description of the configuration>
As shown in FIG. 1 , a head-up display (HUD) 2 can be mounted below a windshield WS provided on a vehicle C.

The HUD1 projects a virtual image V by projecting display light Li representing vehicle information onto the windshield WS (a reflective and transmissive member) which has a free-form curved surface shape that is inclined so that the front end of the vehicle is lower. The HUD1 emits the display light Li diagonally upward toward the rear of the vehicle. The display light Li emitted to the HUD1 is reflected by the windshield WS. A user (e.g., a passenger of the vehicle C) who views the display light Li reflected by the windshield WS at viewpoint EP can view the projected virtual image V as a display image floating behind the windshield WS.

The virtual image V displays vehicle information that is highly likely to draw the occupant's (user's) attention, such as vehicle information such as speed and engine RPM, route guidance displays such as turn-by-turn and maps, and warning displays such as blind spot monitors and speed limit exceeding warnings. This provides a driving environment with reduced viewpoint movement and eye focal length adjustments. The virtual image V includes characters and icons indicating this information as well as a background portion, and when viewed from the occupant's plane, it has, for example, a rectangular shape.

The HUD 1 mainly operates in two modes. One is a display mode in which the HUD 1 projects the display light Li onto the windshield WS, as shown in FIG. 1, so that the virtual image V can be viewed from the viewpoint EP. The other is a pause mode (parking mode) in which the HUD 1 does not project the display light Li onto the windshield WS, so that the virtual image V cannot be viewed from the viewpoint EP. The HUD 1 in the parking mode in which the display light Li is not projected onto the windshield WS is located in a position where the external light (mainly sunlight) incident on the HUD 1 from the windshield WS direction is not reflected in the direction in which the display light Li is incident (the direction in which the display unit is optically located) based on the principle of reverse light propagation. This prevents the display unit from being illuminated by external light and becoming hot when the HUD 1, which is considered to be in a state in which the vehicle C is stopped, is in the parking mode.
To switch between these modes, the HUD 1 rotates the reflecting unit 30 using a configuration that will be described later.

In the display mode, the HUD 1 can change the optical path of the display light Li by a configuration described below in order to adjust the height of the viewpoint EP at which the virtual image V can be viewed. In the present disclosure, as shown in the drawings, the optical path can be changed to three types: a shorter display light Ls, a center display light Lc, and a toler display light Lt. In the display mode, the shorter display light Ls is projected by the HUD 1 onto a relatively lower part of the windshield WS to display the virtual image V. In the toler display light Lt, the HUD 1 projects the display light Li onto a relatively upper part of the windshield WS to display the virtual image V. In the center display light Lc, the display light passes between the two display optical paths described above to display the virtual image V.
The HUD 1 includes a display unit Di and a reflecting unit Mi.

The display unit Di, which is an example of a display, is a member that emits display light Li. In the present disclosure, the display light Li is emitted in the direction F. Examples of members that emit display light Li include a configuration using a TFT liquid crystal module, a configuration using an organic EL, and a projector using a DMD (Digital Micro-mirror Device). In a configuration using a TFT liquid crystal module, for example, the display unit Di is configured to have a backlight unit and a liquid crystal display element that are fixed and connected to a control unit, and the liquid crystal display element that displays information under the control of the control unit emits display light Li when illuminated by illumination light emitted from a backlight unit whose blinking is controlled under the control of the control unit. However, it goes without saying that the effects of the configuration of the present disclosure can be achieved with any configuration that can emit display light other than the examples.

The reflecting portion Mi reflects the display light Li. The reflecting portion Mi is, for example, a mirror whose surface that reflects the display light Li has a concave free-form shape, and the mirror surface is formed by a technique such as vapor deposition or sputtering. The reflecting portion Mi reflects the display light Li while magnifying it. The reflecting portion Mi can use a hard synthetic resin or inorganic glass as a base material. In addition, it is desirable that the reflecting portion Mi has a shape that offsets the distortion of the virtual image V that is expected to occur on the windshield WS due to the free-form shape.

The reflecting portion Mi may be provided with a holder. The holder holds the reflecting portion Mi so that it can rotate around the rotation axis A. The holder may be made of a hard metal such as magnesium or iron, or a hard synthetic resin such as ABS resin.

2 shows the configuration of the HUD 1, meter 2, and battery 3 mounted on the vehicle C. The magnitude relationships among the three voltages mentioned in the description are as follows. The voltage values are merely examples.
Typical value of first voltage = 3.3V < second threshold voltage = 3.5V < first threshold voltage = 3.8V

The HUD 1 further includes a microcomputer (an example of a control unit) 10, a first power source 11, a second power source 12, and a voltage determination unit 13.

The microcomputer 10, which is an example of a processor, can be a microcomputer equipped with a memory unit such as a ROM or RAM (not shown) used for storing a specific program and various data, and as a memory area during calculations, a CPU for performing calculations according to the specific program, and an input/output interface. The control unit is electrically connected to the display unit Di, the power unit, and electronic devices external to the HUD1. Based on vehicle information received from on-board devices external to the HUD1, the control unit generates images to be displayed on the display unit Di, controls the display of the display unit Di, controls the illuminance of the display unit Di, and controls the rotation of the reflector Mi.

The microcomputer 10 is supplied with power by applying a first voltage V1 from a first power supply 11. The microcomputer 10 can determine whether the first voltage V1 is equal to or greater than the second threshold voltage based on the voltage applied to the power supply monitor pin 10a. For example, in this disclosure, the typical values of the second voltage V2 applied to the power supply monitor pin 10a are 5V, and the typical values of the first voltage V1 are 3.3V. The microcomputer 10 can determine whether the first voltage V1 is equal to or greater than the second threshold voltage based on the 5V potential of the second voltage V2.

The second threshold voltage is a reference voltage that notifies the microcontroller 10 that an abnormality has occurred in the first voltage V1 while the microcontroller 10 is operating when the second threshold voltage is set to a value greater than the recommended operating range voltage (e.g., 3.3 V ± 0.2 V) and is less than a voltage that may cause an internal abnormality (first threshold voltage, absolute maximum rated voltage, e.g., 3.8 V).

The microcomputer 10 is electrically connected to a microcomputer 20 mounted on the meter 2 described below. The microcomputer 10 can communicate various electrical signals with the microcomputer 20, and can transmit, for example, a voltage abnormality occurrence signal ER that notifies of an abnormality in the first voltage V1 (above the second threshold voltage).

The first power supply 11 and the second power supply 12 are transformers that transform the power supply voltage VB applied from the outside (such as the battery 3). The first power supply 11 applies the transformed first voltage V1 to the microcontroller 10 and the voltage determination unit 13 to supply power. The second power supply 12 applies the transformed second voltage V2 to the voltage determination unit 13 and the power supply monitor pin 10a of the microcontroller 10 to supply power.

The first power source 11 and the second power source 12 can be various types of transformers, for example, linear regulators, switching regulators, and other DC/DC converters.

The voltage determination unit 13 determines whether the potential of the first voltage V1 is equal to or greater than a threshold value or less than a threshold value. Specifically, when the first voltage V1 is equal to or greater than the first threshold voltage, the voltage determination unit 13 turns the enable signal EN to an OFF state, and stops the operation of the first power supply 11. When the first voltage V1 is less than the first threshold voltage, the voltage determination unit 13 turns the enable signal EN to an ON state, and causes the first power supply 11 to operate normally.

The voltage determination unit 13 may be configured to determine the magnitude of the first voltage V1, and may be implemented, for example, as a reset IC or a comparator. The voltage determination unit 13 operates when the second voltage V2 is applied and power is supplied. As the voltage determination unit 13 is an element that monitors the first voltage V1, it is desirable for the voltage determination unit 13 to be provided via a power source separate from the first voltage V1.

The meter 2 is a display device that displays vehicle information to the user. For example, it can be configured as an electronic display capable of displaying images using TFT or organic EL, a pointer-type instrument consisting of a pointer and an index, a warning light, or the like. The meter 2 includes a microcomputer 20 and a power supply 21. The microcomputer 20 can be configured in the same manner as the microcomputer 10. The power supply 21 is electrically connected to the battery 3, which is an external power supply, and the HUD 1, and supplies power supplied from the battery 3 to the HUD 1 and the microcomputer 20. The power supply 21 outputs the voltage output by the battery 3 to the HUD 1 as the power supply voltage VB (e.g., 12 V). The power supply 21 applies a voltage (e.g., 3.3 V) obtained by stepping down the power supply voltage VB to the microcomputer 20. When the voltage abnormality occurrence signal ER is input from the microcomputer 20, the meter 2 notifies the user using a warning light or an electronic display.

Battery 3 is a power supply device composed of a secondary battery or the like. For example, a 12V power supply composed of a lead-acid battery can be used as battery 3.

<1-2. Explanation of behavior>
The HUD 1 operates based on the following behavior.

(When the first voltage is within the recommended operating range voltage)
The HUD 1 performs normal operation and displays vehicle information to the user.

(When the first voltage is equal to or greater than the first threshold voltage)
When an abnormality occurs in the first power supply 11, the first voltage may become equal to or higher than the first threshold voltage. In this case, a voltage equal to or higher than the absolute maximum rated voltage is applied to the microcomputer 10, and the microcomputer 10 is exposed to a state in which the inside of the microcomputer 10 may be destroyed. In such a case, it is desirable for the microcomputer 10 to be shut down immediately before transmitting an error signal to the outside.

Therefore, in this embodiment, the voltage determination unit 13, rather than the microcontroller 10, determines whether the first voltage V1 is equal to or greater than the first threshold voltage. When the voltage determination unit 13 determines that the first voltage V1 is equal to or greater than the first threshold voltage, it turns off the enable signal EN and stops the operation of the first power supply 11.

This allows the state in which a voltage exceeding the absolute maximum rated voltage is applied to the microcomputer 10 to be quickly eliminated, resulting in a vehicle display device with improved resistance to power supply abnormalities. A specific failure case is when a voltage exceeding the absolute maximum rated voltage is applied, and the inside of the microcomputer 10 is destroyed in some way, causing the display of the display unit Di to be fixed at a white image with maximum light intensity. In this case, the virtual image V obstructs the user's field of vision. With the configuration disclosed herein, even if the inside of the microcomputer 10 is destroyed, the operation of the entire HUD 1 can be stopped by stopping the operation of the first power supply 11. Furthermore, with this configuration, the microcomputer 10 can be shut down before some kind of failure causes the microcomputer 10 to enter a loop and the operation of the microcomputer 10 cannot be changed.

(When the first voltage is equal to or greater than the second threshold voltage and less than the first threshold voltage)
When an abnormality occurs in the first power supply 11, the first voltage V1 may be equal to or higher than the second threshold voltage and lower than the first threshold voltage. In other words, the first voltage V1 does not exceed the absolute maximum rated voltage, but deviates from the recommended operating voltage range. In this case, the microcomputer 10 does not need to immediately stop operating, but it is desirable for the microcomputer 10 to take action such as notifying the user of the abnormality.

As a way of notifying the user of an abnormality, for example, the microcontroller 10 outputs a voltage abnormality occurrence signal ER to the microcontroller 20 of the meter 2, and in response, the microcontroller 20 utilizes the display function of the meter 2 to notify the user that an abnormality has occurred in the device (abnormality in the first voltage V1).

This configuration prevents the device from being destroyed by a voltage abnormality, while still allowing operation to continue and informing the user of a minor voltage abnormality. This results in a vehicle display device with improved resistance to power abnormalities.

[Modification]
Although the vehicle display device of the present invention has been described using the above-mentioned embodiment as an example, the present invention is not limited to this, and it goes without saying that various improvements and changes to the display are possible in other configurations as well, without departing from the gist of the present invention.

For example, the voltage determination unit 13 has been shown to be a reset IC, but this is not limited to this configuration. For example, as described above, any element whose output changes electrically depending on the magnitude of the voltage, such as a comparator, may be used. However, in this disclosure, it is desirable to use a reset IC because it is an inexpensive and simple configuration.

C Vehicle WS Windshield EP Viewpoint V Virtual image A Rotation axis Di Display unit (an example of a display)
Mi Reflector Li, Lt, Lc, Ls Display light

VB Battery voltage V1 First voltage V2 Second voltage

1. Head-up display (HUD, an example of a vehicle display device)
10. Microcomputer (an example of a processor)
11 First power source 12 Second power source 13 Voltage determination unit

2 meter 20 microcomputer 21 power supply

Claims (3)

A vehicle display device that is mounted on a vehicle and displays vehicle information,
a display for displaying the vehicle information;
a processor for controlling the display;
a first power supply that transforms an externally applied power supply voltage into a first voltage and supplies power to the processor;
a second power source that transforms the power source voltage to a second voltage;
Operates based on the second voltage;
operating the first power supply normally when the first voltage is less than a first threshold voltage;
a voltage determination unit that stops the first power supply when the first voltage is equal to or higher than a first threshold voltage ;
The processor outputs a voltage abnormality occurrence signal to an external device when the first voltage is lower than the first threshold voltage and equal to or higher than the second threshold voltage . the vehicle display device is a head-up display,
The display device for a vehicle according to claim 1 , wherein the device is a meter. The display device for a vehicle according to claim 1 , wherein the voltage determination unit is a reset IC.

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