JP2023110188A - Display unit, control method, and program - Google Patents

Abstract

To provide a display unit hardly impairs the visibility of an object.SOLUTION: A display unit comprises: acquisition means that acquires distance information on an object to be measured; image forming means that has display means displaying an image; projection means that projects the image to be visually recognizable as a virtual image; and control means that acquires the distance information and controls the image forming means. When a second distance from an eye-box corresponding to the positions of the eyes of an observer to the object to be measured is shorter than a first distance from the eye-box to the virtual image, the control means performs control of reducing the quantity of light output by the image forming means.SELECTED DRAWING: Figure 1

Description

The present invention relates to a display device that allows a user to visually recognize a virtual image.

2. Description of the Related Art There is a display device called a head-up display (hereinafter also referred to as HUD) that allows a user to visually recognize an image in a space different from the position where the image is actually displayed by using the illusion of the human eye. Such an image that is visually recognized in a space different from the position where the image is actually displayed is called a virtual image.

Patent Literature 1 discloses a HUD capable of changing the viewing distance at which a user who is a passenger of a mobile object visually recognizes a virtual image.

JP 2016-118423 A

However, in the HUD disclosed in Patent Literature 1, an optical element or the like is moved in order to change the viewing distance of the virtual image. Since the optical elements and the like are moved, there is some time lag in changing the viewing distance. For example, if a vehicle suddenly cuts in front of the vehicle and the vehicle overlaps the position where the virtual image is visually recognized, the virtual image becomes an obstacle and the user cannot confirm the vehicle that has cut in until the adjustment of the visual distance is completed. may become difficult to carry out. In this way, when an object such as a vehicle overlaps the position where the virtual image is visually recognized, it may be difficult for the user to check the object.
SUMMARY OF THE INVENTION An object of the present invention is to provide a display device that does not easily impair the visibility of objects.

A display device according to an embodiment of the present invention comprises: acquisition means for acquiring distance information of an object to be measured; image forming means having display means for displaying an image; and projecting the image to make it visible as a virtual image. A projection device, and a control device that acquires the distance information and controls the image forming device. When a second distance from the eyebox to the object to be measured is shorter than a first distance from the eyebox corresponding to the eye position of the observer to the virtual image, the image forming means control to reduce the amount of light output from

ADVANTAGE OF THE INVENTION According to this invention, the display apparatus which does not impair the visibility of an object easily can be provided.

1 is a schematic diagram showing the configuration of a HUD system; FIG. FIG. 4 is a schematic diagram showing the relationship between the forward vehicle and the visual distance of the virtual image; 4 is a flow chart explaining the operation of the HUD system;

[First embodiment]
BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this embodiment, as an application example of the image display device, a head-up display (HUD) system mounted on a vehicle, which is a moving body, is used.

The outline and configuration of the HUD system 1 will be described with reference to FIGS. 1 and 2. FIG. FIG. 1 is a schematic diagram showing a HUD system 1 and a portion of an automobile 100 on which the HUD system 1 is mounted. FIG. 2 is a schematic diagram showing the relationship between the distance to the forward vehicle 200 and the distance to the virtual image, with the automobile 100 as a reference. Note that the positional relationship of each part will be described with the forward direction being defined as the traveling direction of the automobile 100 .

An overview of the HUD system 1 will be described with reference to FIG. A HUD system 1 is mounted on a vehicle 100 . For the sake of simplification, FIG. 1 shows only a part of the automobile 100, such as the windshield 101, which is the front window glass, the dashboard 102, which is the interior structure of the vehicle, and the exterior part 103. As shown in FIG.

The HUD system 1 is composed of a HUD device 140 , a windshield 101 , and a front distance measuring section 110 arranged toward the space ahead of the automobile 100 . For example, the forward ranging unit 110 has LiDAR (Light Detection and Ranging), and can perform ranging using LiDAR. LiDAR can perform distance measurement of an object by irradiating laser light and detecting reflected light from the object, and can acquire distance information to the object.

HUD device 140 is located inside dashboard 102 . The HUD device 140 has an image forming section 120 , a projecting section 130 , a driving section 160 , a control section 150 and a storage section 151 . In this embodiment, the HUD device 140 is installed so that the display image formed by the image forming section 120 is projected onto the windshield 101 from below by the projecting section 130 . Each component of the HUD device 140 will be described below.

The image forming unit 120 forms and displays a projection source image projected by the projecting unit 130 . The image forming section 120 includes a liquid crystal panel 121 and a backlight section 122 . The liquid crystal panel 121 has a group of pixels capable of controlling light transmission and non-transmission. The backlight unit 122 is a light source device using light emitting diodes or the like. The liquid crystal panel 121 is arranged in the illumination direction (forward direction) of the backlight section 122 and selectively transmits the illumination light of the backlight section 122 for each pixel based on the display signal sent from the control section 150 . Accordingly, the image forming unit 120 can display a desired projection source image. Note that the image forming unit 120 may operate so as to display an image recorded in the storage unit 151 under the control of the control unit 150 without forming an image.

The projection unit 130 has an optical system that projects the image formed by the image forming unit 120 toward the windshield 101 as a projected image. The light of the projected image is reflected on the inner surface of the windshield 101 and directed toward an eyebox 180 assumed to be the position of the user's eyes. Note that the eyebox 180 is not a specific point, but a spatial area having a certain extent. In this embodiment, the user is the driver of the automobile 100 . The projected image is formed as a virtual image on the eyebox 180, preferably on the user's pupil. The projected image is visually recognized by the user as a virtual image (see 141n and 141f) in the space in front of the windshield 101, which is a transparent reflecting member. Using the position of the eyebox 180 as a reference, the distances to the virtual images 141n and 141f are denoted by Ln and Lf, respectively. The virtual image 141n is an image when the distance Ln from the eyebox 180 is relatively small with respect to the distance Lf, and the angle corresponding to the half angle of view is denoted by Yn. The virtual image 141f is an image when the distance Lf from the eyebox 180 is relatively large with respect to the distance Ln, and the angle corresponding to the half angle of view is denoted by Yf.

The projection unit 130 is composed of a zoom lens 132 and a mirror 131 . The zoom lens 132 is composed of a movable lens 1321 movable in the direction of arrow 171 and a fixed lens 1322 . The projection unit 130 can change the distance at which the user recognizes the virtual image from the eyebox 180 within the range from Ln to Lf (see arrow 172) according to the movement of the movable lens 1321. FIG. In this embodiment, the distance from the eyebox 180 at which the user recognizes (visually recognizes) the virtual image, that is, the distance from the eyebox 180 to the virtual image 141n or the virtual image 141f is also referred to as "visual distance".

The direction of the optical axis 190 in the image forming section 120 indicates the projection direction of the zoom lens 132 . A mirror 131, which is a concave mirror, is arranged at the projection destination. Mirror 131 reflects light in the direction of windshield 101 , ie, in the direction indicated by optical axis 191 . The projected image of the zoom lens 132 is magnified by a predetermined magnification and the distortion is corrected.

The light of the projected image directed from the mirror 131 toward the windshield 101 is further reflected by the reflecting section 192 . The reflecting portion 192 is a portion where the optical axis 191 and the windshield 101 intersect. Light reflected by the reflecting portion 192 is guided in the direction indicated by the optical axis 193 , that is, toward the eyebox 180 . The projected image is formed as a virtual image on the user's pupil, and the user can visually recognize the virtual image 141n and the virtual image 141f.

The drive unit 160 includes an actuator such as a motor and is controlled by the control unit 150 . Drive unit 160 moves movable lens 1321 by a predetermined amount in the direction of arrow 171 according to a drive instruction signal from control unit 150 . In this embodiment, it is assumed that the visual distance increases when the movable lens 1321 is moved in a direction that shortens the distance between the movable lens 1321 and the fixed lens 1322 . In this embodiment, data obtained by combining the viewing distance and the position information of the movable lens 1321 is also referred to as "movable lens position data". The movable lens position data is stored in the storage unit 151 in advance.

The control unit 150 has, for example, a CPU (Central Processing Unit) and controls the HUD system 1 . The control unit 150 acquires the distance information output from the forward distance measuring unit 110 and controls the driving unit 160 , the image forming unit 120 and the storage unit 151 . In the present embodiment, the signal that the control unit 150 transmits when controlling the image forming unit 120 is also referred to as a “display instruction signal”. When the image forming unit 120 receives the display instruction signal, various controls such as turning on and changing the luminance of the backlight unit 122 and changing the content of the image displayed on the liquid crystal panel 121 are performed. Also, the control unit 150 transmits a driving instruction signal to the driving unit 160 based on the movable lens position data.

The storage unit 151 includes, for example, a rewritable nonvolatile memory. The storage unit 151 stores in advance image data to be displayed on the image forming unit 120, movable lens position data, and the like.

Next, with reference to FIG. 2, the relationship between the forward vehicle 200 and the visual distance will be described. FIG. 2A is a schematic diagram showing a state in which the viewing distance is adjusted to Lf by driving the movable lens 1321 of the projection unit 130. FIG. The distance from the eyebox 180 to the rear portion of the forward vehicle 200 at this time is denoted as D1. In FIG. 2A, the relationship is "Lf>D1". Since the virtual image is recognized within the same distance range as the forward vehicle 200 , the user may feel uncomfortable as if the virtual image were embedded in the forward vehicle 200 . In this state, the virtual image that appears to be embedded in the forward vehicle 200 is an obstacle for the user, which may make it difficult for the user to recognize the distance to the forward vehicle 200 .

FIG. 2B is a schematic diagram showing a state in which the viewing distance is adjusted to Ln by driving the movable lens 1321 of the projection unit 130 from the state of FIG. 2A. In FIG. 2B, the relationship is "Ln<D1". In this state, the user can easily recognize the distance to the forward vehicle 200 without appearing as if a virtual image is embedded in the forward vehicle 200 , which is the actual scene.

2A and 2B have been described on the assumption that the distance D1 between the eyebox 180 and the rear portion of the forward vehicle 200 does not change, for the sake of simplicity. Since the distance D1 may actually change with time, the viewing distance is changed by driving the movable lens 1321 of the projection unit 130 according to the distance D1. At that time, the control unit 150 performs control so that the viewing distance of the virtual image is less than the distance D1.

Next, the operation of the HUD system 1 will be described with reference to the flowchart of FIG. It should be noted that the controlling entity of the operation control of the HUD system 1 is the control unit 150, and the following processing is realized by the CPU executing the control program.

First, the HUD system 1 is powered on. After that, in S301, the control unit 150 reads position information for driving the movable lens 1321 from the storage unit 151 based on the viewing distance of the virtual image determined from the surrounding environment of the automobile 100, the running speed, and the like. The control unit 150 transmits a drive instruction signal based on the difference between the read position information and the current position information of the movable lens 1321 to the drive unit 160 . The drive unit 160 that has received the drive instruction signal drives the movable lens 1321 . The visual distance of the virtual image currently displayed by the HUD system 1 will be described as "visual distance Lx".

In S<b>302 , the control unit 150 reads data of an image to be displayed on the image forming unit 120 from the storage unit 151 , and transmits the data together with the light emission luminance value of the backlight unit 122 to the image forming unit 120 as a display instruction signal. The image data read out from the storage unit 151 is image data determined from the surrounding environment of the automobile 100, the traveling speed, and the like. Upon receiving the display instruction signal, the image forming unit 120 controls the backlight unit 122 to emit light with desired luminance and controls the liquid crystal panel 121 . The illumination light of the backlight unit 122 is selectively transmitted for each pixel, and a desired image is visually recognized by the user as a virtual image at the viewing distance Lx. Note that the light emission luminance value associated with the display instruction signal transmitted to the image forming unit 120 in S302 is treated as the initial value.

In S<b>303 , the control unit 150 acquires distance information from the forward rangefinder 110 . The front ranging unit 110 is arranged facing the space ahead of the automobile 100 . Control unit 150 can acquire distance information to forward vehicle 200 ( FIG. 2 ) from front ranging unit 110 . The distance between forward rangefinder 110 and forward vehicle 200, that is, the distance from eyebox 180 to the rear of forward vehicle 200, which is the actual scene, is denoted by Dx.

In S304, the control unit 150 compares the visual distance Lx of the currently displayed virtual image with Dx obtained in S303. When the control unit 150 determines that “Lx<Dx” in S304, the forward vehicle 200 and the virtual image are separated from each other as shown in FIG. 2(B). In this case, the process of S305 is executed. When the control unit 150 determines in S304 that "Lx≧Dx", it is visually recognized as if a virtual image is embedded in the preceding vehicle 200 as shown in FIG. 2(A). In this case, the process of S306 is executed.

In S<b>306 , the control unit 150 transmits to the image forming unit 120 a display instruction signal for reducing the luminance of the backlight unit 122 from the initial value. As a result, the brightness of the virtual image is lowered, making it difficult to focus on the virtual image, so that the user is less likely to be distracted by the virtual image. As a result, the virtual image that appears to be embedded in the forward vehicle 200 is less likely to interfere with the visual recognition of the forward vehicle 200 .

In S307, the control unit 150 executes standby processing. The control unit 150 advances the process to S308 after waiting for a predetermined time (denoted as T) to elapse. In S<b>308 , the control unit 150 acquires Dx from the front distance measuring unit 110 again.

In S309, the control unit 150 compares the viewing distance Lx of the currently displayed virtual image with Dx acquired in S308. When the control unit 150 determines that “Lx<Dx” in S309, the processing of S310 is executed. As an example of determining that "Lx<Dx", the forward vehicle 200 may move from the front of the automobile 100 due to a lane change or the like during the period of the predetermined time T. FIG. Alternatively, as shown in FIG. 2B, the forward vehicle 200 may be farther away than the visual distance Lx from the own vehicle. On the other hand, when the control unit 150 determines that “Lx≧Dx” in S309, the processing of S311 is executed. As an example of determining that "Lx≧Dx", the forward vehicle 200 may exist in a range closer than the visual distance Lx even after the predetermined time T has passed, as shown in FIG. 2(A).

In S<b>310 , the control unit 150 transmits a display instruction signal to the image forming unit 120 to return the luminance of the backlight unit 122 to the initial value. As a result, the brightness of the virtual image increases and the visibility of the virtual image improves. After the process of S310, the process of S305 is executed.

On the other hand, in S311, the control unit 150 determines the viewing distance Lx to be shorter than Dx. The control unit 150 reads position information for driving the movable lens 1321 from the storage unit 151 based on the determined new viewing distance Lx (<Dx). The control unit 150 transmits a drive instruction signal based on the difference between the read position information and the current position information of the movable lens 1321 to the drive unit 160 . The drive unit 160 that has received the drive instruction signal drives the movable lens 1321 . As a result, the viewing distance Lx of the virtual image is changed to a shorter distance. After the process of S311, the process of S308 is executed.

In S<b>308 , the control unit 150 reacquires Dx from the front distance measuring unit 110 . Subsequently, in S309, the control unit 150 compares the current viewing distances Lx and Dx. When the control unit 150 determines in S309 that "visual distance Lx≧Dx", the distance between the own vehicle and the forward vehicle 200 has changed, and Dx is equal to or less than the visual distance changed in S311. In this case, the process of S311 is executed, and the control unit 150 changes the viewing distance again.

On the other hand, when the control unit 150 determines that "Lx<Dx" in S309, the user does not see a virtual image embedded in the forward vehicle 200 as shown in FIG. 2B. In this case, the process of S310 is executed, and the control unit 150 transmits to the image forming unit 120 a display instruction signal for returning the light emission luminance of the backlight unit 122 to the initial value.

In S305, the control unit 150 executes power-off determination processing. When the control unit 150 determines that the power of the HUD system 1 should be turned off, the series of processing ends. Further, when the control unit 150 determines that the power of the HUD system 1 should be kept on, the process of S301 is executed again.

With respect to the viewing distance changed in S311 of FIG. 3, the control unit 150 then re-determines a new viewing distance based on the content displayed in S301, the traveling speed of the automobile 100, and the like. Alternatively, when the control unit 150 confirms that the distance between the own vehicle (automobile 100) and the preceding vehicle 200 is greater than or equal to a predetermined distance (threshold value), the control unit 150 performs processing to restore the original visual distance.

In this embodiment, the luminance of the virtual image can be sufficiently reduced by controlling the emission luminance of the backlight unit 122 to be reduced while the movable lens 1321 is moving. It is possible to avoid or suppress the user's difficulty in grasping the sense of distance to the actual scene as a result of being disturbed by a virtual image that appears to be embedded in the actual scene. In addition, the HUD system 1 responds to a temporary approach to an obstacle during a time equal to or less than a threshold time (predetermined time T), and the visual distance of the virtual image is frequently changed. It does not interfere with your concentration on driving.

[Other embodiments]
Next, other embodiments for the first embodiment will be described. In another embodiment, in S304 of FIG. 3, the control unit 150 determines whether or not the viewing distance Lx is equal to or greater than the distance to the actual scene (Dx or greater). When determining that “Lx≧Dx”, the control unit 150 further compares the difference between the viewing distances Lx and Dx with a predetermined value (threshold value). When the control unit 150 determines that the difference between the visual distances Lx and Dx is equal to or greater than a predetermined value (threshold value or more), or the inter-vehicle distance between the host vehicle and the target vehicle is equal to or less than a predetermined threshold value, the vehicles approach each other. If so, the control unit 150 executes warning processing for the user. As a warning processing method, there is a method in which the control unit 150 reads the warning image data from the storage unit 151 and performs control to display the warning image as a virtual image, thereby notifying the user. Alternatively, there is a method of notifying the user by controlling the control unit 150 to generate a warning sound using a speaker (not shown) arranged in the car 100 .

In the first embodiment, control is performed to reduce the emission luminance of the backlight unit 122 in S306 of FIG. In another embodiment, when the control unit 150 determines that “Lx≧Dx” in S309 of FIG. For example, if the forward vehicle 200 is in a range closer than the visual distance Lx to the own vehicle even after the predetermined time T has passed, control is performed to reduce the emission brightness of the backlight unit 122 . After that, the control unit 150 shifts to S311 and resets the viewing distance. After confirming in S309 that the distance between the host vehicle and the forward vehicle 200 has become equal to or greater than the reset viewing distance, the control unit 150 performs control to increase the emission brightness of the backlight unit 122 in S310.

Further, in FIG. 3, instead of the control for reducing the light emission luminance of the backlight unit 122 based on the determination result of S306 or S309, extinction control of the backlight unit 122 may be executed as necessary. For example, the control unit 150 determines whether or not it is possible to ensure sufficient forward visibility by controlling the amount of light output from the image forming unit 120 to be reduced. Assume that the distance between the vehicle and the host vehicle is momentarily shortened due to the sudden braking of the preceding vehicle. In this case, when the control unit 150 determines that the forward visibility cannot be sufficiently ensured by controlling the amount of light to decrease, the control unit 150 sets the amount of light output from the image forming unit 120 to zero and performs control to hide the virtual image. Alternatively, the control unit 150 may perform extinction control as control for reducing the light emission luminance without performing the above-described determination.

The projection unit 130 configured by the mirror 131 and the zoom lens 132 (lens group) shown in FIG. 1 is an example. In other embodiments, it is possible to employ a configuration in which a mirror member is moved as a projection unit capable of changing the viewing distance. Further, in other embodiments, in addition to the control of changing the viewing distance, the control of the display position on the liquid crystal panel 121 can be applied to the control of changing the position of the virtual image with respect to the target area of the real scene. Control unit 150 performs control to change the visual distance or position of the virtual image, control to change the visual distance and position of the virtual image, control to reduce the amount of light output from image forming unit 120, or extinction control.

In the above embodiment, an example in which the image forming section 120 has the liquid crystal panel 121 and the backlight section 122 is shown. In other embodiments, self-emissive devices such as organic EL (Electro-Luminescence) displays can be used.

According to the above embodiment and other embodiments, it is possible to realize a HUD system that does not hinder the observer's perception of the distance to the measurement object.

Although the present invention has been described in detail above based on its preferred embodiments, the present invention is not limited to these specific embodiments, and various forms within the scope of the present invention are possible. Included in the technical scope. For example, application of the HUD system is not limited to automobiles, and can be applied to mobile bodies such as motorcycles, trains, aircraft, construction machinery, and ships. Furthermore, the HUD system can be applied to an AR (Augmented Reality) display device or the like that superimposes desired information on real world video information.

The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in the computer of the system or apparatus reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

1 HUD system 110 forward ranging unit 120 image forming unit 130 projection unit 140 HUD device 150 control unit 160 driving unit

Claims (12)

Acquisition means for acquiring distance information of an object to be measured;
an image forming means having display means for displaying an image;
Projecting means for projecting the image to make it visible as a virtual image;
a control means for acquiring the distance information and controlling the image forming means;
When a second distance from the eyebox to the object to be measured is shorter than a first distance from the eyebox corresponding to the eye position of the observer to the virtual image, the image forming means A display device characterized by performing control to reduce the amount of light output by the. When the second distance is shorter than the first distance, the control means controls the projection means to change the first distance to a distance shorter than the second distance. The display device according to claim 1, characterized by: 3. The display device according to claim 1, wherein the control means performs warning processing for notifying the approach of a moving object equipped with the display device to the object to be measured. The control means performs warning processing when determining that the first distance is greater than or equal to the second distance and that a difference between the first distance and the second distance is greater than or equal to a threshold. 3. The display device according to claim 1 or 2, characterized in that: The image forming means has light emitting means for illuminating the display means,
5. The display device according to any one of claims 1 to 4, wherein the control means controls the light emission means to reduce the light emission luminance or extinguish the light. When the control means determines that the second distance is shorter than the first distance even after a predetermined time has elapsed, the control means performs control to reduce the light emission luminance or extinguishment control. The display device according to claim 5. The control means sets the first distance after performing control for reducing the light emission luminance or performing extinction control, and the light emission is performed when the second distance is equal to or greater than the first distance after setting. 7. The display device according to claim 6, wherein control is performed to increase luminance. 4. The display device according to claim 3, wherein the projection means projects the image onto a reflecting member provided on the moving body. Acquisition means for acquiring distance information of an object to be measured;
an image forming means having display means for displaying an image;
Projecting means for projecting the image to make it visible as a virtual image;
a control means for acquiring the distance information and controlling the image forming means;
The control means controls to change the distance from the eyebox to the virtual image or to change the position of the virtual image with respect to the distance from the eyebox corresponding to the eye position of the observer to the measurement target. 1. A display device that performs control for reducing the amount of light output from said image forming means or extinction control. A control method executed by a display device,
a step of acquiring distance information of a measurement target;
forming an image with an image forming means having a display means;
Projecting the image to make it visible as a virtual image;
a control step of acquiring the distance information and controlling the image forming means;
In the control step, if a second distance from the eyebox to the measurement target is shorter than a first distance from the eyebox corresponding to the eye position of the observer to the virtual image, the image forming means A control method for a display device, characterized in that control is performed to reduce the amount of light output from the display device. A control method executed by a display device,
a step of acquiring distance information of a measurement target;
forming an image with an image forming means having a display means;
Projecting the image to make it visible as a virtual image;
a control step of acquiring the distance information and controlling the image forming means;
In the control step, the distance from the eyebox to the virtual image or the position of the virtual image is changed with respect to the distance from the eyebox corresponding to the eye position of the observer to the measurement target. 2. A control method for a display device, wherein control for reducing the amount of light output from said image forming means or extinction control is performed. A program for causing a computer of a display device to execute each step according to claim 10 or 11.

Images