JP2025023009A - Head-up display, control method, program, and storage medium - Google Patents

Abstract

To provide a head-up display which can suitably reduce burden on eyes of an observer without changing virtual image distance.SOLUTION: A head-up display 2 includes a light source unit 4, and a combiner 9. A control part 55 of the light source unit 4 recognizes a position of an attention object Obj on the basis of an image Im or the like acquired from a camera 3 for imaging a front scenery. The control part 55 displays a virtual image Iv so as to form an image at virtual image distance Lv previously set by a driver by the combiner 9. Moreover, the control part 55 displays at least one virtual image Iv at a position in the vicinity of the attention object Obj when the attention object Obj is positioned in a virtual image vicinity range Rn with the virtual image distance Lv as a reference.SELECTED DRAWING: Figure 9

Description

The present invention relates to display technology for head-up displays.

In head-up displays and head-mounted displays that display a virtual image superimposed on the scenery ahead, there are known techniques for adjusting the virtual image distance, which is the distance from the observer's viewpoint to the virtual image. For example, Patent Document 1 discloses a binocular head-mounted display that changes the virtual image distance based on the distance from the viewpoint to the background in order to avoid the virtual image being observed as being embedded in the background when the actual background position is closer to the viewpoint than the virtual image position. Patent Document 2 discloses a head-up display that includes an optical reflector for near focus and an optical reflector for far focus in order to set the virtual image position to a near focus when the vehicle is stopped and to a far focus at the same distance as the focus when the vehicle is moving.

JP 2010-139589 A JP 2005-247180 A

When configuring a head-up display so that the virtual image distance can be changed depending on the distance from the viewpoint to the background, as in Patent Document 1, it is necessary to provide both an optical reflector for close focus and an optical reflector for far focus, as in Patent Document 2, which creates the problem of an increased size of the optical system.

The present invention has been made to solve the above problems, and its main objective is to provide a head-up display that can suitably reduce the strain on the observer's eyes without changing the virtual image distance.

The invention described in the claims is a head-up display mounted on a moving body and displaying a virtual image superimposed on a forward view, comprising an acquisition means for acquiring the position of an object contained in the forward view, and a control means for causing a display means to display the virtual image so as to be imaged at a preset distance from the driver of the moving body, and characterized in that, when the object is located within a predetermined distance range including the preset distance from the driver, the control means causes the display means to display at least one virtual image in a position near the object.

The invention described in the claims is a control method executed by a head-up display mounted on a moving body and displaying a virtual image superimposed on a forward view, the control method comprising an acquisition step of acquiring the position of an object included in the forward view, and a control step of causing a display means to display the virtual image so as to be imaged at a preset distance from the driver of the moving body, the control step being characterized in that, when the object is located within a predetermined distance range including the preset distance from the driver, the display means is caused to display at least one virtual image in a position near the object.

The invention described in the claims is a program executed by a computer that controls a head-up display mounted on a moving body and displays a virtual image superimposed on a forward view, and causes the computer to function as an acquisition means for acquiring the position of an object included in the forward view, and a control means for causing a display means to display the virtual image so as to be imaged at a preset distance from the driver of the moving body, and the control means causes the display means to display at least one virtual image in a position near the object when the object is located within a predetermined distance range including the preset distance from the driver.

1 shows a schematic configuration of a display system. 1 shows a schematic configuration of a navigation device. 1 shows a schematic configuration of a head-up display. 2 shows a schematic configuration of a light source unit. 1 is an example of a view ahead of the vehicle as viewed from the driver's seat when no attention object is detected. 11 is a diagram showing the positional relationship between an object of attention and a vehicle when the nearest object of attention is located farther away than the virtual image vicinity range. FIG. An example of the display of the combiner in the example of Figure 6 is shown. 11 is a diagram showing the positional relationship between an object of attention and a vehicle when the nearest object of attention is present within a virtual image vicinity range. FIG. 9 shows a first display example of the combiner in the example of FIG. 8 . 9 shows a second display example of the combiner in the example of FIG. 8 . 11 is a diagram showing the positional relationship between an object of attention and a vehicle when the nearest object of attention is located closer than the virtual image vicinity range. FIG. 12 shows a first display example of the combiner in the example of FIG. 11 . 12 shows a second display example of the combiner in the example of FIG. 11 . 11 shows a modified example of the display of the combiner shown in FIG. 10 . 13 shows a modified example of the display of the combiner shown in FIG. 12.

In one preferred embodiment of the present invention, a head-up display mounted on a moving body and displaying a virtual image superimposed on a forward view includes an acquisition means for acquiring the position of an object included in the forward view, and a control means for causing a display means to display the virtual image so as to be imaged at a preset distance from the driver of the moving body, and when the object is located within a predetermined distance range including the preset distance from the driver, the control means causes the display means to display at least one virtual image in a position near the object.

The head-up display includes an acquisition means and a control means. The acquisition means acquires the position of an object included in the scenery ahead. The control means causes the display means to display the virtual image so as to be formed at a preset distance from the driver of the moving body. Furthermore, when the object is located within a predetermined distance range including the preset distance from the driver, the control means causes the display means to display at least one virtual image at a position near the object. Here, the "nearby position" refers to a position close enough that the driver can simultaneously view the object and the virtual image. In this way, when the distance from the driver to the object and the virtual image distance are close, the head-up display displays the virtual image near the object, thereby allowing the driver to simultaneously view the virtual image and the object. As a result, the head-up display can suitably reduce the strain on the driver's eyes when viewing the virtual image and the object without changing the virtual image distance.

In one aspect of the head-up display, the control means moves the display position of at least one of the virtual images being displayed to a position near the object. With this aspect, the head-up display allows the driver to visually recognize the virtual image and the object in an optimal manner.

In another aspect of the head-up display, when the position of the object is closer to the driver than the predetermined distance range, the control means makes at least one of the virtual images being displayed invisible, or moves the display position of the virtual image to a position that is not near the object. In general, when a virtual image and an object that are at different distances from the driver are simultaneously viewed, the driver's eyes are strained. Therefore, with this aspect, the head-up display can suitably suppress simultaneous viewing of a virtual image and an object that are at different distances from the driver.

In another aspect of the head-up display, when the position of the object is farther from the driver than the predetermined distance range, the control means moves the display position of at least one of the virtual images being displayed to a position near the object. Generally, focusing between distant foci places less strain on the eyes, so this aspect of the head-up display allows the driver to visually recognize the virtual image and the object in an optimal manner.

In another aspect of the head-up display, when the object is located within the predetermined distance range, the control means displays an undisplayed virtual image in a position near the object. This aspect also allows the head-up display to allow the driver to easily view the virtual image and the object without straining the driver's eyes.

In another aspect of the head-up display, the control means determines, for each type of object, whether or not to superimpose a virtual image to be displayed near the object on the object. With this aspect, the head-up display can, for example, superimpose a virtual image on an object that is sufficiently visible even with a superimposed virtual image, and display an object whose visibility is reduced when a virtual image is superimposed without superimposing a virtual image.

In another preferred embodiment of the present invention, a control method executed by a head-up display mounted on a moving body and displaying a virtual image superimposed on a forward scene includes an acquisition step of acquiring the position of an object included in the forward scene, and a control step of causing a display means to display the virtual image so as to be imaged at a preset distance from the driver of the moving body, and the control step causes the display means to display at least one virtual image in a position near the object when the object is located within a predetermined distance range including the preset distance from the driver. By executing this control method, the head-up display can suitably reduce the strain on the driver's eyes when viewing the virtual image and the object without changing the virtual image distance.

In yet another embodiment of the present invention, a program executed by a computer that controls a head-up display mounted on a moving body and that displays a virtual image superimposed on a forward scene causes the computer to function as an acquisition means for acquiring the position of an object included in the forward scene, and a control means for causing the display means to display the virtual image so as to be imaged at a preset distance from the driver of the moving body, and the control means causes the display means to display at least one virtual image in a position near the object when the object is located within a predetermined distance range including the preset distance from the driver. By executing this program, the head-up display can preferably reduce the strain on the driver's eyes when viewing the virtual image and the object without changing the virtual image distance. Preferably, the program is stored in a storage medium.

Below, a preferred embodiment of the present invention will be described with reference to the drawings.

[General Configuration]
(1) System configuration
Fig. 1 shows an example of the configuration of a display system 100 according to an embodiment. As shown in Fig. 1, the display system 100 is mounted on a vehicle Ve, and includes a navigation device 1, a head-up display 2, and a camera 3. Note that, instead of the configuration shown in Fig. 1, the head-up display 2 may incorporate a function equivalent to the navigation device 1.

The navigation device 1 has a function of providing route guidance from a departure point to a destination. The navigation device 1 can be, for example, a stationary navigation device installed in a vehicle Ve, a PND (Portable Navigation Device), or a mobile terminal such as a smartphone.

The head-up display 2 is a device that generates an image (also called a "guidance image") that displays information that assists driving, and allows the driver to view the guidance image as a virtual image from the driver's eye position (eye point). As guidance images, the head-up display 2 displays, for example, arrows indicating the direction of the guidance route, information about guidance points such as right and left turn points, information about the travel of the vehicle Ve such as the vehicle speed, information indicating the location of facilities, information indicating the direction ahead, and information about traffic laws. The head-up display 2 is supplied with various information necessary for generating the guidance image, such as information about the guidance route, from the navigation device 1.

The camera 3 is fixed facing the front of the vehicle Ve, and generates an image (also called "image Im") of the front of the vehicle Ve at a predetermined interval. The camera 3 supplies the generated image Im to the head-up display 2. As described later, the head-up display 2 detects an object (also called "attention object Obj") that the driver should pay attention to and is included in the scenery ahead based on the image Im. The attention object Obj is, for example, a vehicle ahead, a traffic light, a traffic sign, a person, and/or a facility. In this embodiment, the head-up display 2 detects a vehicle ahead and a traffic light as the attention object Obj. Preferably, the camera 3 is a stereo camera that captures the scenery ahead from different directions. In this case, the head-up display 2 can also serve as a means for detecting the distance between the attention object Obj and the vehicle Ve based on the image Im.

When the navigation device 1 is a mobile terminal such as a smartphone, the navigation device 1 may be held by a cradle or the like. In this case, the navigation device 1 may exchange information with the head-up display 2 via the cradle or the like. Also, the head-up display 2 may receive the image Im via the navigation device 1 instead of receiving the image Im directly from the camera 3. In this case, the camera 3 transmits the image Im to the navigation device 1, and the navigation device 1 transfers the image Im to the head-up display 2.

(2) Configuration of the Navigation Device Fig. 2 shows the configuration of the navigation device 1. As shown in Fig. 2, the navigation device 1 includes a stand-alone positioning device 10, a GPS receiver 18, a system controller 20, a disk drive 31, a data storage unit 36, a communication interface 37, a communication device 38, an interface 39, a display unit 40, an audio output unit 50, and an input device 60.

The independent positioning device 10 includes an acceleration sensor 11, an angular velocity sensor 12, and a distance sensor 13. The acceleration sensor 11 is, for example, a piezoelectric element, detects the acceleration of the vehicle Ve, and outputs the acceleration data. The angular velocity sensor 12 is, for example, a vibration gyroscope, detects the angular velocity of the vehicle Ve when the vehicle Ve changes direction, and outputs the angular velocity data and the relative orientation data. The distance sensor 13 measures a vehicle speed pulse consisting of a pulse signal generated in association with the rotation of the wheels of the vehicle Ve.

The GPS receiver 18 receives radio waves 19 carrying downlink data including positioning data from multiple GPS satellites. The positioning data is used to detect the absolute position (also called the "current position") of the vehicle Ve from latitude and longitude information, etc.

The system controller 20 includes an interface 21, a CPU (Central Processing Unit) 22, a ROM (Read Only Memory) 23, and a RAM (Random Access Memory) 24, and controls the entire navigation device 1.

The interface 21 performs interface operations with the acceleration sensor 11, angular velocity sensor 12, distance sensor 13, and GPS receiver 18. From these, vehicle speed pulses, acceleration data, relative direction data, angular velocity data, GPS positioning data, absolute direction data, etc. are input to the system controller 20. The CPU 22 controls the entire system controller 20. The ROM 23 has a non-volatile memory (not shown) in which control programs for controlling the system controller 20, etc. are stored. The RAM 24 readably stores various data such as route data preset by the user via the input device 60, and provides a working area for the CPU 22.

The system controller 20, a disk drive 31 such as a CD-ROM drive or a DVD-ROM drive, a data storage unit 36, a communication interface 37, a display unit 40, an audio output unit 50 and an input device 60 are interconnected via a bus line 30.

Under the control of the system controller 20, the disk drive 31 reads and outputs content data such as music data and video data from a disk 33 such as a CD or DVD. Note that the disk drive 31 may be either a CD-ROM drive or a DVD-ROM drive, or may be a drive compatible with both CD and DVD.

The data storage unit 36 is, for example, a HDD, and is a unit that stores various data used in navigation processing, such as map data. The map data includes road data represented by links corresponding to roads and nodes corresponding to the connecting parts of the roads, facility information regarding each facility, etc.

The communication device 38 is composed of, for example, an FM tuner, a beacon receiver, a mobile terminal, or a dedicated communication module, and receives road traffic information such as congestion and traffic information and other information distributed from the VICS (Vehicle Information Communication System, a registered trademark) center via the communication interface 37. The communication device 38 also transmits various information used in navigation processing to the head-up display 2, such as current position information obtained from the GPS receiver 18, information such as vehicle speed pulses obtained from the independent positioning device 10, and map data.

The display unit 40 displays various display data on a display device such as a display under the control of the system controller 20. Specifically, the system controller 20 reads map data from the data storage unit 36. The display unit 40 displays the map data and the like read from the data storage unit 36 by the system controller 20 on the display screen. The display unit 40 includes a graphic controller 41 that controls the entire display unit 40 based on control data sent from the CPU 22 via the bus line 30, a buffer memory 42 that is a memory such as a VRAM (Video RAM) and temporarily stores image information that can be displayed immediately, a display control unit 43 that controls the display 44 such as a liquid crystal display or a CRT (Cathode Ray Tube) based on image data output from the graphic controller 41, and a display 44. The display 44 functions as an image display unit and is, for example, a liquid crystal display device with a diagonal size of about 5 to 10 inches, and is attached near the front panel inside the vehicle.

The audio output unit 50 is configured with a D/A converter 51 that performs D/A (Digital to Analog) conversion of audio digital data sent via the bus line 30 from the CD-ROM drive 31, DVD-ROM 32, or RAM 24 under the control of the system controller 20, an amplifier (AMP) 52 that amplifies the audio analog signal output from the D/A converter 51, and a speaker 53 that converts the amplified audio analog signal into audio and outputs it inside the vehicle.

The input device 60 is composed of keys, switches, buttons, a remote control, a voice input device, etc., for inputting various commands and data. The input device 60 is arranged on the front panel of the main body of the in-vehicle electronic system installed in the vehicle, or around the display 44. In addition, if the display 44 is of the touch panel type, the touch panel provided on the display screen of the display 44 also functions as the input device 60.

(3) Configuration of the Head-Up Display Fig. 3 is a schematic configuration diagram of the head-up display 2. As shown in Fig. 3, the head-up display 2 according to this embodiment includes a light source unit 4 and a combiner 9, and is attached to a vehicle Ve that includes a windshield 25, a ceiling portion 27, a bonnet 28, a dashboard 29, etc.

The light source unit 4 is installed on the ceiling 27 inside the vehicle cabin via support members 5a and 5b, and emits light constituting a guide image showing information to assist driving toward the combiner 9, thereby allowing the driver to visually recognize a virtual image "Iv" through the combiner 9. Hereinafter, the distance from the eye point Pe to the virtual image Iv, as shown in the figure, is also referred to as the "virtual image distance Lv."

The combiner 9 projects the display image emitted from the light source unit 4 and reflects the display image to the driver's eye point "Pe" to display the display image as a virtual image Iv. The combiner 9 has a support shaft 8 installed on the ceiling 27 and rotates around the support shaft 8 as a support shaft. The support shaft 8 is installed, for example, on the ceiling 27 near the upper end of the windshield 25, in other words, near the position where a sun visor (not shown) for the driver is installed. The support shaft 8 may be installed in place of the sun visor described above. The combiner 9 is an example of a "display means" in the present invention.

(4) Configuration of the Light Source Unit Fig. 4 is a diagram showing a schematic configuration of the light source unit 4. As shown in Fig. 4, the light source unit 3 has a light source 54, a control unit 55, and a communication unit 56.

The light source 54 has laser light sources of, for example, red, blue, and green colors, and emits light (also called "display light") that constitutes a display image to be irradiated onto the combiner 9 based on the control of the control unit 55.

The communication unit 56 receives various information used in navigation processing from the navigation device 1 under the control of the control unit 55. For example, the communication unit 56 receives information necessary for generating a guidance image, such as information on a guidance route and information on a current position, from the navigation device 1. The communication unit 56 also receives images Im from the camera 3 at predetermined intervals.

The control unit 55 has a CPU, a ROM for storing control programs and data executed by the CPU, and a RAM for sequentially reading and writing various data as a work memory when the CPU is operating, and performs overall control of the head-up display 2.

The control unit 55 generates a guidance image based on information transmitted from the navigation device 1, and emits display light constituting the guidance image to the light source 54. In this embodiment, the control unit 55 detects one or more attention objects Obj based on the image Im transmitted from the camera 3. Furthermore, the control unit 55 recognizes the distance (also called the "object distance Lo") between the detected attention object Obj and the vehicle Ve (strictly speaking, the eye point Pe) based on the image Im or the output of various radars (not shown). The control unit 55 then appropriately changes the display position on the combiner 9 of the guidance image displayed as the virtual image Iv while keeping the virtual image distance Lv fixed. This will be explained in detail in the "Adjusting the display position" section.

The control unit 55 functions as the "acquisition means," "control means" and a computer that executes the program in this invention.

[Adjust display position]
Next, a method for adjusting the display position of the guide image visually recognized as the virtual image Iv on the combiner 9 will be described. In summary, the control unit 55 determines the display position of the guide image displayed as the virtual image Iv based on the relationship between the object distance Lo of the attention object Obj closest to the eye point Pe and the virtual image distance Lv. In this way, the control unit 55 allows the driver to visually recognize both the attention object Obj and the virtual image Iv in an appropriate manner without straining the driver's eyes.

(1) When there is no attention object Figure 5 is an example of a forward view visually recognized from the driver's seat when the attention object Obj is not detected. In Figure 5, the control unit 55 displays a first guide image 81, which indicates the direction (here, right direction) in which the vehicle Ve should proceed at the next right or left turn point based on the guide route and the distance to the next right or left turn point (here, 2 km), as a virtual image Iv at the lower left of the combiner 9. In addition, the control unit 55 displays a second guide image 82, which indicates the speed of the vehicle Ve (here, 66 km/h), at the lower right of the combiner 9. In this way, when the control unit 55 does not detect the attention object Obj, one or more (here, two) guide images displaying specific information are displayed at predetermined positions.

(2) When the attention object is farther than the virtual image vicinity range Next, a case will be described in which an attention object Obj is detected and the detected closest attention object Obj is farther than the range (also called the "virtual image vicinity range Rn") in the vicinity of the virtual image Iv based on the traveling direction of the vehicle Ve. In this case, the control unit 55 takes into consideration that focusing between far foci places less strain on the eyes, and displays at least one virtual image Iv showing a guide image near the closest attention object Obj.

Figure 6 is a diagram showing the positional relationship between the attention object Obj and the vehicle Ve when the nearest attention object Obj is located farther away than the virtual image vicinity range Rn. In this case, the control unit 55 recognizes the traffic light 91, which is the attention object Obj, based on the image Im, and further calculates the object distance Lo. The control unit 55 also recognizes the virtual image distance Lv, which is a fixed value, for example, by storing it in advance in a memory or the like. Then, based on the virtual image distance Lv, the control unit 55 recognizes the range that is a predetermined distance "L1" forward and backward from the virtual image Iv in the traveling direction of the vehicle Ve as the virtual image vicinity range Rn. Here, the predetermined distance L1 is, for example, determined in advance based on experiments, etc., to a distance at which the driver can view an object in the virtual image vicinity range Rn with the same perspective as the virtual image Iv. The control unit 55 then recognizes that the traffic light 91 is located farther away than the virtual image vicinity range Rn because the maximum distance from the eye point Pe (= Lv + L1) within the recognized virtual image vicinity range Rn is shorter than the object distance Lo of the traffic light 91.

Figure 7 shows an example of the display of the combiner 9 in the example of Figure 6. In the example of Figure 7, the control unit 55 displays the first guide image 81 in a position near the traffic light 91 visible in the combiner 9. In this case, the control unit 55 recognizes the area of the traffic light 91 visible on the combiner 9 from the area of the traffic light 91 extracted from the image Im, and displays the first guide image 81 in a position near the area. At this time, the control unit 55, for example, stores in advance information indicating the correspondence between the display position in the image Im and the display position on the combiner 9, and recognizes the area of the traffic light 91 visible on the combiner 9 by referring to the information.

In general, focusing on distant foci places less strain on the eyes. Therefore, in the example of Figure 7, the driver can easily see the traffic light 91 and the first guidance image 81, both of which are relatively far away, without straining the eyes.

In addition, in the example of FIG. 7, the control unit 55 does not change the display position of the second guide image 82 indicating the vehicle speed from when the attention object Obj does not exist (see FIG. 5). That is, in the example of FIG. 7, the control unit 55 fixes the display position of the second guide image 82 regardless of the positional relationship between the attention object Obj and the virtual image Iv, and changes the display position of the first guide image 81 according to the positional relationship between the attention object Obj and the virtual image Iv. In this way, the control unit 55 may predetermine whether or not to fix the display position of the guide image depending on the type of information indicated by the guide image. As an example, it is not preferable to change the position of an image that indicates the position of a facility by being displayed in correspondence with the position of the facility present in the scenery ahead as viewed from the driver's seat, or an image that indicates the direction, such as which position in the scenery ahead corresponds to the east, from its original display position. For such types of images, the display position may not be changed from the position where it should be displayed.

(3) When the attention object is within the virtual image vicinity range Next, a case will be described where the detected closest attention object Obj is within the virtual image vicinity range Rn. In this case, since the positions of the attention object Obj and the virtual image Iv in the forward direction of the vehicle Ve are approximately the same, the control unit 55 displays at least one virtual image Iv in the vicinity of the attention object Obj visually recognized on the combiner 9. As a result, the attention object Obj and the virtual image Iv that do not need to be focused on in the near and far directions are displayed in the vicinity, and the driver can visually recognize them suitably without straining his/her eyes.

Figure 8 is a diagram showing the positional relationship between the attention object Obj and the vehicle Ve when the nearest attention object Obj is present within the virtual image vicinity range Rn. In this case, the control unit 55 recognizes the attention objects Obj, a traffic light 91 and a truck 92, based on the image Im, and further calculates the object distance Lo between them. Then, based on the calculated object distance Lo, the control unit 55 recognizes that the truck 92 is the nearest attention object Obj. Then, since the difference between the object distance Lo corresponding to the truck 92 and the virtual image distance Lv is within the predetermined distance L1, the control unit 55 determines that the truck 92 is present within the virtual image vicinity range Rn.

Figure 9 shows a first display example of the combiner 9 in the example of Figure 8. In the first display example shown in Figure 9, the control unit 55 displays the first guide image 81 in a position near the truck 92 visible within the combiner 9. In this way, the control unit 55 displays the truck 92 and the first guide image 81 in the vicinity, which do not require focusing on the distance, and allows the driver to view them favorably without straining his or her eyes. In addition, the control unit 55 fixes the display position of the second guide image 82 indicating the vehicle speed, regardless of the presence or absence of the attention object Obj, as in the example of Figure 7. Furthermore, as explained above, the display positions of the image indicating the location of the facility and the image indicating the direction may not be changed from the positions where they should be displayed.

Figure 10 shows a second display example of the combiner 9 in the example of Figure 8. In the second display example shown in Figure 10, the control unit 55 recognizes that the truck 92 is a preceding vehicle by image recognition using the image Im, and newly displays a third guide image 83 indicating the distance to the preceding vehicle in a position near the truck 92. In this way, in the display example shown in Figure 10, when the control unit 55 determines that the truck 92, which is the nearest object of attention Obj, is present within the virtual image vicinity range Rn, the control unit 55 displays the third guide image 83, which has not been displayed until then, in the vicinity of the object of attention Obj. This also allows the control unit 55 to allow the driver to visually recognize the virtual image Iv and the object of attention Obj in an optimal manner without straining the driver's eyes.

(4) When the attention object Obj is closer than the virtual image vicinity range Next, a case where the detected closest attention object Obj is located closer than the virtual image vicinity range Rn will be described. In this case, the control unit 55 does not display the virtual image Iv near the closest attention object Obj because the positions of the closest attention object Obj and the virtual image Iv in the traveling direction of the vehicle Ve are different. This prevents the driver from simultaneously viewing the attention object Obj and the virtual image Iv, which need to be focused on in the distance.

Figure 11 is a diagram showing the positional relationship between the attention object Obj and the vehicle Ve when the nearest attention object Obj is closer than the virtual image vicinity range Rn. In this case, the control unit 55 recognizes that the truck 92 is the attention object Obj and the object distance Lo to the truck 92 based on the image Im. Then, the control unit 55 determines that the truck 92 is closer than the virtual image vicinity range Rn based on the object distance Lo corresponding to the truck 92 and the virtual image distance Lv.

Figure 12 shows a first display example of the combiner 9 in the example of Figure 11. In the display example shown in Figure 12, first, the control unit 55 determines that the display position of the first guide image 81 on the combiner 9 in normal times, that is, the display position at the bottom left of the combiner 9 (see Figure 5), is within a predetermined distance from the area of the truck 92 visible on the combiner 9. The above-mentioned predetermined distance is determined based on experiments, for example, as the distance between the displays at which the driver may simultaneously view two displays on the combiner 9. In this case, the control unit 55 determines that the first guide image 81 is displayed near the truck 92 when the first guide image 81 is displayed at the normal display position (i.e., the bottom left of the combiner 9). Therefore, in this case, the control unit 55 displays the first guide image 81 at a position (here, the top right of the combiner 9) that is at least a predetermined distance away from the area of the truck 92 visible on the combiner 9.

In general, when the object of attention Obj is closer than the virtual image vicinity range Rn, the virtual image Iv and the object of attention Obj have different focal positions in near and far. Therefore, in this case, if the virtual image Iv is displayed near the object of attention Obj, the driver will try to see them at once, and the simultaneous focusing in near and far places a strain on the driver's eyes. Taking the above into consideration, in the example of FIG. 12, the control unit 55 displays the first guidance image 81 at a position on the combiner 9 away from the truck 92, thereby suitably reducing the strain on the driver's eyes.

Figure 13 shows a second display example of the combiner 9 in the example of Figure 11. In the display example shown in Figure 13, the control unit 55 determines that when the first guide image 81 is displayed in the normal position, the first guide image 81 will be displayed near the truck 92, and erases the display of the first guide image 81. In this way, the control unit 55 erases the display of the first guide image 81 to prevent the first guide image 81 from being displayed near the truck 92. This also allows the control unit 55 to prevent the guide image from being displayed near the attention object Obj that is closer than the virtual image vicinity range Rn, and can suitably reduce strain on the driver's eyes.

As described above, the head-up display 2 according to the present embodiment includes the light source unit 4 and the combiner 9. The control unit 55 of the light source unit 4 recognizes the position of the attention object Obj based on the image Im acquired from the camera 3 that captures the forward scenery. The control unit 55 also causes the combiner 9 to display the virtual image Iv so that the image is formed at a virtual image distance Lv set in advance from the driver. Furthermore, when the attention object Obj is located within the virtual image vicinity range Rn based on the virtual image distance Lv, the control unit 55 causes at least one virtual image Iv to be displayed at a position near the attention object Obj. This allows the head-up display 2 to favorably allow the driver to view the virtual image Iv and the attention object Obj without changing the virtual image distance Lv.
12 and 13, the control unit 55 continues to display the second guide image 82 indicating the vehicle speed without changing the display position. In this way, the control unit 55 may determine in advance whether or not to continue to display the guide image without changing the display position even when the attention object Obj is located closer than the virtual image vicinity range Rn, depending on the type of information indicated by the guide image. Since it is not preferable to change the position of an image indicating the location of a facility or an image indicating a direction from its original display position, when the attention object Obj is located closer than the virtual image vicinity range Rn, the display may be erased without changing the position from its original display position.

[Modification]
Preferred modifications of the above-described embodiment will be described below. The following modifications may be applied to the above-described embodiment in any combination.

(Variation 1)
9 and 10 used in the explanation of the section "(3) When an object to be noticed is within the range near a virtual image", when the control unit 55 displays a guide image near the nearest object to be noticed Obj, the control unit 55 displays the guide image at a position that does not overlap with the nearest object to be noticed Obj. Alternatively, the control unit 55 may display the guide image at a position that overlaps with the nearest object to be noticed Obj in this case.

Figure 14 shows a modified example of the display of the combiner 9 shown in Figure 10. In Figure 14, the control unit 55 displays the third guide image 83 at a position overlapping the truck 92. Even in this case, the control unit 55 allows the driver to simultaneously view the truck 92 and the third guide image 83, which do not require focusing on near and far, and allows the driver to appropriately recognize the presence of the truck 92 and the contents of the third guide image 83 without straining the driver's eyes. Note that the control unit 55 may also display the guide image at a position overlapping the nearest object of attention Obj when the nearest object of attention Obj is farther away than the virtual image vicinity range Rn.

Preferably, the control unit 55 may also determine whether or not to display a guide image superimposed on each type of target attention object Obj. For example, when the object to be displayed nearby is a traffic light, the control unit 55 may display the guide image near the traffic light without superimposing it, and when the object to be displayed nearby is a vehicle ahead, the control unit 55 may display the guide image superimposed on the vehicle ahead.

(Variation 2)
When the object of attention Obj is closer than the virtual image vicinity range Rn, the control unit 55 may display a guidance image whose display position should be changed in the vicinity of another object of attention Obj that is within the virtual image vicinity range Rn or farther away than the virtual image vicinity range Rn.

Figure 15 shows a modified display of the combiner 9 shown in Figure 12. In Figure 15, instead of the truck 92, a passenger car 93, which is the vehicle ahead, is traveling at a position closer than the virtual image vicinity range Rn. In the example of Figure 15, the passenger car 93 is lower in height than the truck 92, so a traffic light 91 that is located farther away than the virtual image vicinity range Rn can also be seen through the combiner 9.

In this case, the control unit 55 displays the first guide image 81, which is normally displayed near the passenger car 93, at a position that is not near the passenger car 93 and is near the traffic light 91, which is another object of attention Obj that is located farther away than the virtual image vicinity range Rn. In this way, the control unit 55 can prevent the driver from simultaneously viewing the passenger car 93 and the first guide image 81, which require focusing at a distance, while allowing the driver to simultaneously view the traffic light 91 and the first guide image 81, which place less of a burden on the driver when viewing them simultaneously.

(Variation 3)
3, the head-up display 2 has a combiner 9, and allows the driver to view a virtual image Iv based on the light emitted from the light source unit 4 reflected by the combiner 9. However, the configuration to which the present invention can be applied is not limited to this. Alternatively, the head-up display 2 may not have the combiner 9, and may allow the driver to view a virtual image Iv based on the light emitted from the light source unit 4 reflected by a windshield 25. In this case, the windshield 25 is an example of a "display means" in the present invention.

The position of the light source unit 4 is not limited to being installed on the ceiling 27. Alternatively, the light source unit 4 may be installed on the dashboard 29 or inside the dashboard 29. If installed on the dashboard 29, the dashboard 29 is provided with a combiner 9, or light is reflected directly from the light source unit 4 onto the windshield 25 to allow the driver to recognize the virtual image Iv. If installed inside the dashboard, the dashboard 29 is provided with an opening for passing light to the combiner 9 or the windshield 25.

(Variation 4)
A part of the processing of the control unit 55 may be executed by the system controller 20. For example, a guidance image to be displayed by the head-up display 2 may be generated by the system controller 20, and the light source unit 4 of the head-up display 2 may receive the guidance image.

In another example, the system controller 20 may receive an image Im from the camera 3 via the communication device 38 instead of the head-up display 2, and perform detection processing of the attention object Obj and measurement processing of the object distance Lo. In this case, the system controller 20 transmits the detection result of the attention object Obj and the measurement result of the object distance Lo to the head-up display 2 via the communication device 38.

In yet another example, in addition to the process of detecting the attention object Obj and the process of measuring the object distance Lo, the system controller 20 may recognize the positional relationship between the attention object Obj and the virtual image vicinity range Rn based on the measured object distance Lo, similar to the control unit 55 in the embodiment, and determine the display position of the guidance image according to the positional relationship. In this case, the system controller 20 causes the head-up display 2 to display the guidance image at a predetermined position by transmitting information specifying the display position of the guidance image to the head-up display 2 via the communication device 38.

In this modified example, the system controller 20 functions as the "acquisition means," "control means" and computer that executes the program in the present invention.

The head-up display 2 may also have some or all of the functions of the navigation device 1. In this case, the light source unit 4 may have various sensors, such as a memory that stores map data and a GPS receiver.

REFERENCE SIGNS LIST 1 navigation device 2 head-up display 4 light source unit 9 combiner 25 windshield 28 bonnet 29 dashboard 100 display system

Claims (1)

A head-up display mounted on a moving body and displaying a virtual image superimposed on a forward view,
An acquisition means for acquiring a position of an object included in the forward scene;
a control means for controlling a display means to display the virtual image so as to be formed at a preset distance from a driver of the moving body,
The head-up display is characterized in that the control means causes the display means to display at least one virtual image at a position near the object on the display means when the object is located within a predetermined distance range near the virtual image based on the direction of travel of the moving body.