JP7769871B2 - Head-up display - Google Patents

Description

The present invention relates to a head-up display for a vehicle, and is suitable, for example, as a display device that projects a display image onto the windshield.

Conventionally, a head-up display of this type has been known, for example, to project display light from a display onto the vehicle's windshield (projection member) to display a virtual image, as described in Patent Document 1.

In addition, the display content of these head-up displays includes, for example, guidance displays such as arrows showing the destination of the vehicle, as described in Patent Document 2.

Japanese Patent Application Laid-Open No. 2003-344801 JP 2018-149884 A

However, when this guidance display is projected onto a windshield or other surface, the scenery ahead of the vehicle is used as the background, making it difficult to grasp relative positions, posing a challenge when used as a route guidance display.

The object of the present invention is to address the above-mentioned issues and provide a head-up display that can provide easy-to-understand guidance displays.

The head-up display of the present invention is
In a head-up display that displays a virtual image in the space in front of the driver,
a projection unit that projects the image;
a control unit that receives route guidance information and vehicle information and draws and generates the image that provides route guidance to the driver based on the information;
The control unit
A guide image showing the route direction to the destination;
a road surface image in which a part of the road on which the host vehicle is traveling is shown in color and a shadow portion is provided below the guide image ;
Furthermore, the control unit can blur the outline of the shadow and use perspective to move the display position of the guide image and the corresponding shadow upward, and when the guide image is displayed at the top, the shadow is drawn with a stronger blurring process than when it is displayed at the bottom .

The control unit also draws the guide image with a gap between it and the shadow.

The head-up display of the present invention can provide easy-to-understand guidance.

1 is a schematic diagram of a head-up display mounted on a vehicle according to an embodiment of the present invention; FIG. 2 is a cross-sectional view of a main part showing the internal configuration of the head-up display. Block diagram showing the configuration related to image drawing FIG. 10 is a diagram showing a display example relating to route guidance. FIG. 5 is a diagram showing a display example in which the guide image has been moved from FIG. 4 .

An embodiment of the present invention applied to a head-up display for a vehicle will be described below with reference to the accompanying drawings.

As shown in Figure 1, a head-up display projected display light L is projected by a display device 12, which is a display unit provided inside the instrument panel 11 of a vehicle 10, and reflected by the windshield 13 of the vehicle 10 toward the user (driver) 14 of the vehicle 10, thereby displaying a virtual image V. In other words, the head-up display emits (projects) display light (image) L emitted from a liquid crystal display (projection unit) 20 (described below) onto the windshield 13, and allows the user 14 to view the display image (virtual image) V obtained by this emission. This allows the user 14 to observe the virtual image V superimposed on the scenery ahead of the vehicle 10.

As shown in Figure 2, the display device 12 is mainly composed of a liquid crystal display 20, a first reflector 30, a second reflector 40, and a housing 50.

The liquid crystal display 20 is primarily composed of a light source 21 consisting of a light-emitting diode mounted on a wiring board R, and a TFT-type liquid crystal display element (display element) 22 located in front of (directly above) the light source 21 so that illumination light from the light source 21 passes through to form display light L. This means that the light source 21 is located behind (directly below) the liquid crystal display element 22, and the liquid crystal display element 22 displays predetermined information (the information to be displayed, described below) using the light emitted from the light source 21.

The liquid crystal display element 22 also displays the information to be displayed, such as the vehicle's 10 speed, remaining energy, time, and route guidance images, using numerical values, icons, and other images via an element drive circuit (not shown). The liquid crystal display 20 outputs display light L consisting of light in the visible wavelength range. For example, a light source 21 that emits white light can be used, and the light emitted from this light source 21 is transmitted through the liquid crystal display element 22 to output display light L containing the desired image. Note that the information to be displayed is not limited to vehicle information such as the vehicle's speed and remaining energy, and any display format can be used.

The first reflector 30 includes a cold mirror 31. The cold mirror 31 reflects light in the visible wavelength range (450-750 nm), which includes the emission wavelength range of the liquid crystal display 20, with a high reflectance (e.g., 80% or more), and reflects light outside the visible wavelength range with a low reflectance. In this case, the cold mirror 31 used is one that reflects light outside the visible wavelength range, particularly light in the infrared wavelength range (infrared rays or solar heat rays), with a low reflectance (e.g., 15% or less). Light that is not reflected by the reflective layer of the cold mirror 31 is configured to pass through the cold mirror 31.

The second reflector 40 includes a concave mirror 41 that reflects the display light L from the cold mirror 31 (i.e., the liquid crystal display element 22), and a mirror holder 42 that holds the concave mirror 41.

The concave mirror 41 has a second reflective layer 41a formed by vapor deposition on a resin substrate made of polycarbonate with a concave surface. The concave mirror 41 is installed at an angle so that the second reflective layer 41a faces the cold mirror 31 and the translucent cover and can be seen from the translucent cover.

The concave mirror 41 magnifies the display light L from the cold mirror 31 and reflects (projects) it toward the translucent cover (windshield 13 of the vehicle 10). This means that the concave mirror 41 magnifies the display light L reflected by the cold mirror 31 and projects this magnified display light L toward the windshield 13 through the translucent cover. The concave mirror 41 is adhered to the mirror holder 42 with a double-sided adhesive member. The mirror holder 42 is made of synthetic resin (e.g., ABS resin) and is fixed to the housing 50.

The housing 50 is made of, for example, a black, light-blocking synthetic resin material, and is formed in a generally box-like shape. The interior space 51 holds and houses the LCD display 20, first reflector 30, and second reflector 40, and is provided with an opening window 52 through which the upper part of the concave mirror 41 of the second reflector 40 (on the windshield 13 side) opens.

The housing 50 is also provided with a light-transmitting cover 53, which serves as an emission section, to cover the open window 52. This light-transmitting cover 53 is made of a light-transmitting synthetic resin material (e.g., acrylic resin), is formed in a curved shape (curved surface), and functions as a light-transmitting member through which the display light L reflected by the concave mirror 41 passes. In other words, the display light L reflected by the cold mirror 31 and the concave mirror 41 is projected onto the windshield 13 through the light-transmitting cover 53 formed on the housing 50, thereby displaying the virtual image V.

As shown in FIG. 3, the head-up display H also includes a circuit board (not shown) that mounts a control unit 60 that receives various signals from the vehicle's ECU (electronic control unit) and calculates the output content of the liquid crystal display 20. In this case, the circuit board is held in the housing 50 of the display device 12.

The control unit 60 is powered by power supplied from an on-board battery (not shown), and can be a microcomputer equipped with a data storage unit (not shown) such as ROM or RAM (not shown) used to store predetermined programs and various data and as a memory area during calculations, a CPU that performs calculations according to the predetermined programs, and an input/output interface, etc.

The control unit 60 is network-connected to various on-board ECUs and has an input port 61 that inputs route guidance information from a navigation system device and vehicle information measured by various sensors. The control unit 60 is also connected to the liquid crystal display 20 and has a drawing processing unit 62 that generates images to be displayed on the liquid crystal display 20 based on the input route guidance information and vehicle information. The control unit 60 outputs a drive signal to the liquid crystal display 20 to prompt the image generated by the drawing processing unit 62 to be displayed.

An example of the display light (image) L generated by the control unit 60 will be described using Figures 4 and 5.

Figures 4 and 5 show route guidance display lights L that are displayed when a vehicle approaches an intersection L1. In this case, an example of the display light L is shown, urging the driver to proceed straight ahead as guidance. Using perspective, the control unit 60 generates a lane marking image (including a center line image) L2 indicating the width of the road ahead of the vehicle, a road surface image L3 showing a portion of the road surface ahead of the vehicle (near the vehicle), and a guidance image L4 consisting of an arrowhead icon indicating the route direction, each in color, and displays the display light L containing these on the LCD display 20. In this case, the lane marking image L2 is drawn in white, the road surface image L3 in blue, and the guidance image L4 in green. The white background in the figures is actually drawn in black, and the user 14 can see the scenery ahead of the vehicle through the virtual image V projected onto the windshield 13.

The road surface image L3 has grid lines L5 superimposed using perspective, making it easier for the user 14 to recognize distance and perspective. Additionally, the road surface image L3 has a shadow L6 drawn at a distance below the guide image L4, creating the impression and making it appear as if it is floating above the road surface. This shadow L6 is oval in shape and drawn in black (or a darker blue than the road surface image L3). Furthermore, the outer edge (boundary) is blurred to indicate that it is a shadow of the guide image L4, and the distance between it and the guide image L4 makes it easier to recognize the guide position relative to the road surface image L3.

By transitioning the display of the guide image L4 and the shadow L6 with an animation that moves from bottom to top, it is possible to guide the user's 14 line of sight and make the direction easier to understand. For example, as shown in Figure 5, when the guide image L4 and the shadow L6 are displayed moving to the back (top), the guide image L4 and the shadow L6 become smaller in size as they move. Furthermore, as the display position of the shadow L6 moves to the top, the strength of the blurring process increases, emphasizing the sense of perspective. Note that the blurring process can be performed using various image processing methods, such as filters such as Gaussian processing and gradation.

This head-up display includes a head-up display H that displays an image as a virtual image V in the space ahead of the user 14, a liquid crystal display 20 that projects the image, and a control unit 60 that inputs route guidance information and vehicle information and draws and generates the image that provides route guidance to the user 14 based on this information. The control unit 60 draws and generates the image, which includes a guidance image L4 that indicates the route direction to the destination, and a road surface image L3 that is colored to resemble part of the vehicle's driving path and has a shadow L6 below the guidance image L4.

In addition, the control unit 60 can use perspective to move the display position of the guide image L4 and its corresponding shadow L6 upward. When the shadow L6 is displayed at the top, it is drawn with a stronger blurring process than when it is displayed at the bottom, thereby emphasizing the sense of perspective and making it easier to understand the positional relationship.

In addition, by displaying the road surface image L3, the control unit 60 can visually recognize the road surface image L3 as a reference (reference surface) position, even though the background scenery ahead of the vehicle changes, particularly when driving, making it easier to grasp the relative position of the guidance image L4. Furthermore, by displaying grid lines L5 on the road surface, a sense of perspective and distance can be expressed.

While the head-up display of the present invention has been described using the configuration of the above-described embodiment as an example, the present invention is not limited to this, and various improvements and display changes are possible in other configurations without departing from the spirit of the present invention. For example, while the above-described embodiment shows an LCD display 20 being used as the display, it is possible to use a DMD (digital mirror device) or an electromagnetically driven laser beam scanning MEMS mirror as the display, as long as it generates display light containing an image, and achieve the same effects as the above-described embodiment. Furthermore, the display can also be projected onto a dedicated combiner rather than the windshield.

Furthermore, while the guide image L4 is illustrated as an arrowhead-shaped icon, other shapes can also be used as the guide image as long as they indicate directionality.

The control unit 60 can also display the color and shape of lane markings, including center lines, to match the actual road based on the route guidance information. Furthermore, by detecting the position of the user's 14 eyes, the control unit 60 can also display the lane markings superimposed on the actual road lane markings.

In addition, while the example shows the circuit board having the control unit 60 being provided on the display device 12, it can also be provided on a separate vehicle ECU. In this case, the display device 12 can be configured to input a video signal via a communication line and display an image on the LCD display 20.

The present invention relates to a head-up display, and is suitable as a display device that is mounted on mobile objects such as automobiles, motorcycles, or agricultural or construction machinery, and projects and displays vehicle information, turn-by-turn displays, route guidance such as route guides, road information, and the like.

10 Vehicle 11 Instrument panel 12 Display device (head-up display)
13 Windshield 14 User (driver)
20 Liquid crystal display (projection section)
L3 Road surface image L4 Guidance image L6 Shadow area

Claims (2)

In a head-up display that displays a virtual image in the space in front of the driver,
a projection unit that projects the image;
a control unit that receives route guidance information and vehicle information and draws and generates the image that provides route guidance to the driver based on the information;
The control unit
A guide image showing the route direction to the destination;
a road surface image in which a part of the road on which the host vehicle is traveling is shown in color and a shadow portion is provided below the guide image ;
Furthermore, the control unit can blur the outline of the shadow and move the display position of the guide image and the corresponding shadow upward using perspective, and when the guide image is displayed at the top, the shadow is drawn with stronger blurring than when the guide image is displayed at the bottom.
Head-up display. The head-up display according to claim 1 , wherein the control unit draws the guide image with a gap between the guide image and the shadow portion.