JP2020166077A - Video display system, video display method, program, and movable body - Google Patents

Abstract

To provide a video display system that can prevent a reduction in a user's visibility of a virtual image.SOLUTION: A video display system 10 comprises: a screen 130 on which an image for displaying a virtual image for a user of a vehicle 300 is projected; a light source unit 110 that emits a laser beam; a scanning unit 120 that performs two-axis scanning of the laser beam on the screen to project the image on the screen; and a control unit 100 that creates an image, controls the light source unit 110 by using an image signal for projecting the created image on the screen with the laser beam, receives input of sensing information indicating the brightness of the outside by using an illuminance sensor 150, and controls the scanning unit 120 according to the brightness indicated by the sensing information. When the sensing information indicates a first brightness, the control unit 100 causes the scanning unit 120 to reduce the magnitude of at least one amplitude in the axial direction in the two-axis scanning compared with a case where the sensing information indicates a second brightness darker than the first brightness.SELECTED DRAWING: Figure 4

Description

The present disclosure relates to video display systems, video display methods, programs and mobiles.

Patent Document 1 discloses a projector in which a laser is used as a light source. Further, a head-up display (Head-Up Display, hereinafter also referred to as HUD) that directly displays information in a human field of view by using such a projector is known.

JP-A-2010-243809

The present disclosure provides an image display system and the like that can suppress a decrease in visibility of a virtual image by a user.

An image display system mounted on a moving body according to one aspect of the present disclosure and allowing a user of the moving body to visually recognize an image projected on a screen as a virtual image. The projected screen, the light source unit that emits the laser beam, the scanning unit that scans the laser beam on the screen in two axes and projects the image onto the screen, and the image that is generated and generated. The light source unit is controlled by using an image signal for projecting onto the screen with the laser beam, and sensing information indicating the brightness of the outside world measured by the sensor is input, and the sensing information is generated. A control unit that controls the scanning unit according to the indicated brightness is provided, and when the sensing information indicates the first brightness, the control unit applies the scanning unit to the scanning unit in at least one axial direction in the biaxial scanning. The magnitude of the amplitude of is reduced compared to when the sensing information indicates a second brightness that is darker than the first brightness.

The above-mentioned comprehensive or specific embodiment may be realized by a recording medium such as a system, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM, and the system, the method, the integrated circuit, or the computer program. And any combination of recording media may be realized.

According to the video display system of the present disclosure, it is possible to prevent the user from deteriorating the visibility of the virtual image.

FIG. 1 is a diagram showing an example of application of the video display system according to the embodiment to a vehicle. FIG. 2 is a diagram showing an example of an image region displayed on the windshield by the video display system of FIG. FIG. 3 is a diagram showing an example of an image displayed by the video display system of FIG. FIG. 4 is a block diagram showing an example of the functional configuration of the display device according to the embodiment. FIG. 5 is a diagram showing an example of a configuration in which the video display system of FIG. 4 is mounted on a vehicle. FIG. 6 is a diagram showing the relationship (IL curve) between the current applied to the semiconductor laser light source and the light output. FIG. 7 is a graph showing the light output allowed for the semiconductor laser light source depending on the temperature. FIG. 8 is a graph showing the applied current allowed for the semiconductor laser light source according to the temperature. FIG. 9 is a diagram showing an example of the magnitude of the amplitude of scanning by the scanning unit in the first control. FIG. 10 is a diagram showing a first example of the magnitude of the amplitude of scanning by the scanning unit in the second control. FIG. 11 is a diagram showing a first example of the size of the image generated in the first control. FIG. 12 is a diagram showing a first example of the size of the image generated in the second control. FIG. 13 is a diagram showing a second example of the magnitude of the amplitude of scanning by the scanning unit in the second control. FIG. 14 is a diagram showing a second example of the size of the image generated in the first control. FIG. 15 is a diagram showing a second example of the size of the image generated in the second control. FIG. 16 is a diagram showing a third example of the magnitude of the amplitude of scanning by the scanning unit in the second control. FIG. 17 is a diagram showing a third example of the size of the image generated in the first control. FIG. 18 is a diagram showing a third example of the size of the image generated in the second control. FIG. 19 is a flowchart showing an example of the basic operation of the video display system. FIG. 20 is a flowchart showing a first example of amplitude adjustment control of a video display system. FIG. 21 is a flowchart showing a second example of amplitude adjustment control of the video display system. FIG. 22 is a flowchart showing an example of the second control of the video display system.

(Findings by the present inventors)
The present inventors have reached the following findings regarding the technology described in the “Background technology” column.

In the projector described in Patent Document 1, since a virtual image formed in front of the windshield is presented to the driver, the brighter the outside world of the vehicle, the lower the contrast between the virtual image and the actual scene that is the background of the virtual image. , There is a problem that the visibility of the virtual image from the user is lowered.

Therefore, the present inventors have found the following image display system capable of suppressing the deterioration of the visibility of the virtual image by the user even under the condition that the contrast between the virtual image and the real scene is likely to decrease. It came to.

The video display system according to one aspect of the present disclosure is a video display system mounted on a moving body and allowing a user of the moving body to visually recognize an image projected on a screen as a virtual image. A screen on which a visually recognized image is projected, a light source unit that emits laser light, a scanning unit that scans the laser light on the screen in two axes and projects the image onto the screen, and the image are generated. The light source unit is controlled by using an image signal for projecting the generated image onto the screen with the laser beam, and the input of sensing information indicating the brightness of the outside world measured by the sensor is received. A control unit that controls the scanning unit according to the brightness indicated by the sensing information is provided, and when the sensing information indicates the first brightness, the control unit applies to the scanning unit in the biaxial scanning. The magnitude of the amplitude in at least one axial direction is reduced compared to when the sensing information indicates a second brightness that is darker than the first brightness.

Therefore, even under conditions where the outside world is brighter than a predetermined threshold value and the contrast between the virtual image and the actual scene is likely to decrease, the laser light per unit scanning amount can be reduced by reducing the amplitude of scanning by the scanning unit. The density of the laser can be improved. Therefore, the brightness of the virtual image is supplemented, and a clear image can be displayed. Therefore, it is possible to prevent the user from deteriorating the visibility of the virtual image.

Further, when the sensing information indicates the first brightness, the control unit displays the same type of image displayed at the same position in the virtual image regardless of the brightness indicated by the sensing information. In the biaxial scanning, an image enlarged along the axial direction in which the magnitude of the amplitude is reduced may be generated in the scanning portion as compared with the case of showing the second brightness.

Therefore, even when the brightness of the virtual image is supplemented by reducing the amplitude of scanning by the scanning unit, it is possible to suppress the reduction in the size of the virtual image.

Further, the enlargement ratio of the generated image may be the reciprocal of the reduction ratio of the magnitude of the amplitude to be reduced.

Therefore, even when the brightness of the virtual image is supplemented by reducing the amplitude of scanning by the scanning unit, the size of the virtual image can be made equal to that before the amplitude is reduced.

Further, when the sensing information indicates the first brightness, the control unit informs the scanning unit of the magnitude of both the horizontal axis direction and the vertical axis direction in the biaxial scanning, and the sensing information indicates the magnitude of the amplitude. The scanning unit is reduced in reference to the center of the region where the laser beam is scanned as compared with the case of showing the second brightness, and the image projected on the screen is displayed to the user more than other images. A priority image with a high priority may be included.

Therefore, it is possible to effectively suppress the reduction in the brightness of the priority image displayed in the center.

Further, the priority image may be an image for displaying a warning to the user.

Therefore, it is possible to effectively suppress the reduction in the brightness of the image for displaying the warning displayed in the center.

When the sensing information indicates the first brightness, the control unit informs the scanning unit of the magnitude of the amplitude in the horizontal axis direction in the two-axis scanning, and the sensing information indicates the second brightness. It is set that the scanning unit is reduced with reference to the center in the horizontal axis direction of the region where the laser beam is scanned, and the image projected on the screen is always displayed during the operation of the moving body. The always-displayed image that is displayed may be included.

Therefore, it is possible to effectively suppress the reduction in the brightness of the constant image without changing the size of the constant image, which is often long in the vertical axis direction.

Further, the constantly displayed image may be an image showing the operating state of the moving body.

Therefore, it is possible to effectively suppress the reduction in the brightness of the image without changing the size of the image showing the operating state of the moving body.

Further, when the sensing information indicates the first brightness, the control unit informs the scanning unit of the magnitude of the amplitude in the vertical axis direction in the biaxial scanning, and the sensing information indicates the second brightness. When the sensing information indicates the second brightness in the image projected on the screen when the scanning unit is reduced with reference to the center in the vertical axis direction of the region where the laser beam is scanned than when shown. May include a peripheral display image that is set to be displayed near one end of the area on the screen scanned by the scanning unit in the horizontal axis direction.

Therefore, it is possible to effectively suppress the reduction in the brightness of the peripheral display image without changing the size of the peripheral display image that is likely to be displayed at the left and right edges.

Further, the peripheral display image may be an image showing an object on the left or right of the path of the moving body.

Therefore, it is possible to effectively suppress the reduction in the brightness of the image without changing the size of the image showing the object on the left or right of the path of the moving body.

A comprehensive or specific embodiment of the display device may be realized by a recording medium such as a system, a method, an integrated circuit, a computer program, or a computer-readable CD-ROM, and the system, the method, the integrated circuit, or the computer. It may be realized by any combination of programs or recording media.

Hereinafter, the display device according to the embodiment will be described with reference to the drawings. The display device according to the embodiment described below is a comprehensive or specific example. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, etc. shown in the following embodiments are examples, and are not intended to limit the present disclosure. Further, among the components in the following embodiments, the components not described in the independent claims indicating the highest level concept are described as arbitrary components.

[Embodiment]
[1-1. Outline configuration of video display system]
A schematic configuration of the video display system 10 according to the embodiment will be described with reference to FIGS. 1 to 3. In the following, an example in which the video display system 10 is mounted as a head-up display (HUD) on a vehicle 300, which is an example of a moving body, will be described, but the mounting target of the video display system 10 is not limited to the vehicle. Further, FIG. 1 is a diagram showing an example of application of the image display system 10 according to the embodiment to the vehicle 300. FIG. 2 is a diagram showing an example of an image region displayed on the windshield 201 by the video display system 10 of FIG. FIG. 3 is a diagram showing an example of an image displayed by the video display system 10 of FIG.

As shown in FIG. 1, the image display system 10 according to the embodiment is configured as an in-vehicle HUD, and is attached below the windshield 201 of the vehicle 300, specifically, near the upper surface of the dashboard 301. In the present embodiment, the windshield 201 is a front windshield glass, but it may be any part of the windshield glass.

As shown in FIGS. 1 and 2, the image display system 10 is configured to project light forming a virtual image B onto a region D of the windshield 201, which is a display medium. The projected light is reflected by the windshield 201 and travels toward the face of the driver A of the vehicle 300, and is visually recognized by the driver A. The driver A is a user of the image display system 10 sitting in the driver's seat of the vehicle 300. The driver A captures the virtual image B as an image existing outside the vehicle on the opposite side of the windshield 201 against the background of the foreground of the front view seen through the windshield 201, that is, an actually existing object.

In the following description, it is expressed that the driver A visually recognizes the virtual image B by projecting light onto the windshield 201 by the image display system 10 and that the image display system 10 displays the virtual image B using the windshield 201. Sometimes. The display medium of the image display system 10 is not limited to the windshield 201, and may be any display medium in which the light reflected from the projected light of the image display system 10 can be visually recognized by the user.

Referring to FIGS. 1 to 3, the image display system 10 projects light onto the display area D, which is an area surrounded by the alternate long and short dash line on the windshield 201, for example. The display area D is located below the front of the driver A on the windshield 201. Then, the driver A sitting in the driver's seat visually recognizes the image formed by the light projected on the display area D as a virtual image B outside the vehicle on the opposite side of the windshield 201.

[1-2. Video display system configuration]
A detailed configuration of the video display system 10 according to the embodiment will be described with reference to FIGS. 4 and 5. Note that FIG. 4 is a block diagram showing an example of the functional configuration of the video display system 10 according to the embodiment. FIG. 5 is a diagram showing an example of a configuration in which the video display system 10 of FIG. 4 is mounted on the vehicle 300.

Referring to FIGS. 4 and 5, the image display system 10 includes a light source unit 110, a scanning unit 120, a screen 130, a temperature sensor 140, an illuminance sensor 150, and a control unit 100. In FIG. 4, the arrow of the alternate long and short dash line starting from the light source unit 110 indicates an individual optical path in the image display system 10. Specifically, the single-point chain line arrow indicates an optical path of the projected light from the light source unit 110 to the scanning unit 120, and an individual optical path of the scanning light from the scanning unit 120 to the screen 130.

The light source unit 110 emits light for forming a virtual image. The emitted light of the light source unit 110 is projected onto the windshield 201, that is, the display medium 200, thereby forming a virtual image visible to the driver A. For example, the light source unit 110 is configured by a projector including a semiconductor laser light source that emits laser light of red (R), green (G), and blue (B) as a light emitting body. Such a projector enables the formation of a highly visible virtual image. Further, since the image display system 10 including the semiconductor laser light source enables a compact configuration, the space occupied by the image display system 10 on the dashboard 301 can be minimized.

The scanning unit 120 is arranged on the optical path of the light emitted from the light source unit 110. The scanning unit 120 emits the laser light received from the light source unit 110 as scanning light to the screen 130, and scans the screen 130 with the scanning light. Specifically, the scanning unit 120 scans the laser beam in two axes and projects an image on the screen 130. The scanning unit 120 can emit the received light as scanning light in an arbitrary direction, and is realized by, for example, a MEMS (Micro Electro Mechanical Systems) mirror. The scanning light of the scanning unit 120 forms an image on the screen 130 to be displayed as a virtual image. Since the scanning of the screen 130 by the scanning unit 120 is a biaxial scanning, it is a two-dimensional scanning, for example, a raster scan in which the scanning in the horizontal axis direction is sequentially moved in the vertical axis direction.

The screen 130 is a member for projecting an image for displaying a virtual image. In the present embodiment, the screen 130 is a member having a rectangular shape such as a plate shape, a sheet shape, or a film shape, but the shape of the screen 130 is not limited to these. The screen 130 is configured so that the light that reaches it can form an image on the screen 130. In the present embodiment, the screen 130 is composed of a member capable of transmitting light, but may be composed of a member reflecting light. The screen 130 capable of transmitting light is composed of, for example, a transparent member. For example, the screen 130 may be a diffuse screen. The screen 130 projects an image formed on the screen 130 by the scanning light of the scanning unit 120 onto the optical system 160. The screen 130 is arranged within the irradiation range of the scanning light by the scanning unit 120, that is, within the scanning range.

The temperature sensor 140 is a sensor that is arranged in the vicinity of the light source unit 110 and detects the temperature in the vicinity of the light source unit 110. The temperature sensor 140 may be arranged in contact with the light source unit 110 to detect the temperature of the light source unit 110. The temperature sensor 140 may be configured by, for example, a thermistor. Sensing information indicating the temperature of the light source unit 110 measured using the temperature sensor 140 is output to the control unit 100.

The illuminance sensor 150 is a sensor that is arranged on the dashboard 301 and detects the brightness of the outside world of the vehicle 300. The illuminance sensor 150 does not have to be arranged on the dashboard 301 as long as it can detect the brightness of the outside world of the vehicle 300. Sensing information indicating the brightness of the outside world measured by using the illuminance sensor 150 is output to the control unit 100.

The optical system 160 projects an image projected by the screen 130 onto the optical system 160 onto the display area D of the windshield 201 as the display medium 200. The optical system 160 may include a reflecting mirror that reflects light, a lens that magnifies or reduces the transmitted light, and the like. In the present embodiment, the optical system 160 includes reflectors such as a concave mirror, a convex mirror, and a plane mirror, and specifically, as shown in FIG. 5, includes two reflectors 160a and 160b. The reflectors 160a and 160b may be small reflectors that can be housed in a small housing of the image display system 10 (not shown). The reflectors 160a and 160b are arranged so as to face each other. In the present embodiment, the reflecting mirror 160a is a convex mirror and the reflecting mirror 160b is a concave mirror, but each of the reflecting mirrors 160a and 160b may be any one of a plane mirror, a convex mirror and a concave mirror.

The image on the screen 130 is projected toward the first reflector 160a. The image projected on the first reflecting mirror 160a is reflected and magnified by the first reflecting mirror 160a and projected on the second reflecting mirror 160b. Further, the image projected on the second reflecting mirror 160b is reflected and enlarged by the second reflecting mirror 160b and projected on the display medium 200. By using the reflectors 160a and 160b, each image is projected in a desired direction in a magnified state. Further, in the case of the windshield 201, the display medium 200 forms a curved display surface, but by using the reflectors 160a and 160b which are curved mirrors, the distortion of the image projected on the display surface can be adjusted. It is possible. The optical system 160 may include a lens, and the lens may be used to magnify and adjust the orientation of the image. All or part of the optical system 160 may be included as a component in the image display system 10.

The control unit 100 controls the entire video display system 10. For example, the control unit 100 acquires vehicle information from an external device, and calculates an image to be displayed as a virtual image and its position based on the acquired vehicle information. The external device may be, for example, an in-vehicle car navigation system, a speedometer, a water temperature gauge, a human body detector, an eye position detector, an obstacle detector, or the like.

The control unit 100 outputs information indicating the calculation result as a signal to the light source unit 110, and controls the light emission of the light source unit 110. Specifically, the control unit 100 controls the light source unit 110 by using an image signal for generating an image and projecting the generated image on the screen 130 with a laser beam.

The control unit 100 also outputs a control signal to the scanning unit 120 to control the operation of the scanning unit 120. Specifically, the control unit 100 receives input of sensing information from the temperature sensor 140 or the illuminance sensor 150, and controls the scanning unit 120 according to the temperature indicated by the sensing information or the brightness of the outside world.

For example, when the sensing information indicates a temperature outside the predetermined temperature range, the control unit 100 tells the scanning unit 120 the magnitude of the amplitude in at least one axial direction in the biaxial scanning, and the sensing information is within the predetermined temperature range. Make it smaller than when indicating temperature. That is, when the temperature of the light source unit 110 indicates within a predetermined temperature range, the control unit 100 performs the first control to set the magnitude of the scanning amplitude of the scanning unit 120 to a normal magnitude, and the temperature of the light source unit 110 is changed. When the temperature is outside the predetermined temperature range, the second control is performed to reduce the magnitude of the scanning amplitude of the scanning unit 120 as compared with the case of the first control.

Then, when the sensing information indicates a temperature outside the predetermined temperature range, the control unit 100 displays the same type of image displayed at the same position in the virtual image regardless of the temperature indicated by the sensing information in the predetermined temperature range. In biaxial scanning, an image enlarged along the axial direction that reduces the magnitude of the amplitude is generated in the scanning portion as compared with the case of showing the temperature inside. Here, the same type of image is an image for displaying the traveling speed of the vehicle 300, an image for displaying the engine speed (motor speed), an image showing the fuel gauge, and the like. It is the same kind of image in.

Here, a predetermined temperature range will be described with reference to FIGS. 6 to 8.

FIG. 6 is a diagram showing the relationship (IL curve) between the current applied to the semiconductor laser light source and the light output. FIG. 6 shows IL curves at different temperatures.

As shown in FIG. 6, the higher the temperature, the smaller the light output for the same applied current tends to be. That is, the higher the temperature, the more difficult it is to obtain sufficient light output to display a virtual image even if the applied current is increased. Further, when a large current is passed through the semiconductor laser light source, end face destruction is likely to occur, and the life is shortened. In order to prevent such a shortening of the life, a limit is provided on the current flowing through the semiconductor laser light source so that a large current does not flow at high temperatures.

On the other hand, at low temperatures, it is easy to obtain a large light output without increasing the applied current so much, but end face destruction occurs due to the too large light output. For this reason, even at low temperatures, there is a limit on the current flowing through the semiconductor laser light source so that an excessively large light output cannot be obtained, as at high temperatures.

FIG. 7 is a graph showing the light output allowed for the semiconductor laser light source depending on the temperature. FIG. 8 is a graph showing the applied current allowed for the semiconductor laser light source according to the temperature.

As shown in FIG. 7, it can be seen that it is necessary to handle the semiconductor laser light source in an environment of 0 degrees or more and 60 degrees or less in order to obtain the maximum light output. Further, as shown in FIG. 8, it can be seen that it is necessary to handle the semiconductor laser light source in an environment of 0 degrees or more and 40 degrees or less in order to maximize the applied current. As described above, it can be seen that there are an upper limit and a lower limit in the temperature range when trying to obtain a sufficient light output of the semiconductor laser light source. From these facts, it is preferable that the predetermined temperature range is set to a temperature range for obtaining a sufficient light output from the semiconductor laser light source to display a virtual image.

Further, for example, when the sensing information indicates the first brightness, the control unit 100 tells the scanning unit 120 that the amplitude of at least one axial direction in the biaxial scanning is larger than that of the first brightness. Make it smaller than when showing a dark second brightness. That is, when the control unit 100 indicates that the brightness of the outside world is darker or equal to the brightness represented by a predetermined threshold value, the first is that the magnitude of the scanning amplitude of the scanning unit 120 is set to a normal magnitude. When the control is performed and it is shown that the brightness of the outside world is brighter than the brightness represented by a predetermined threshold value, the second control is performed to reduce the magnitude of the scanning amplitude of the scanning unit 120 as compared with the case of the first control. ..

The brightness of the virtual image visually recognized by the user is improved by performing the second control, and the brightness of the displayed virtual image is larger immediately after the second control is performed than immediately before the second control is performed. Therefore, when the first control is switched to the second control, the control unit 100 may control so as to reduce the magnitude of the light output output by the light source unit 110. As a result, the brightness of the virtual image visually recognized by the user can be kept constant even when the first control is switched to the second control. Therefore, it is possible to reduce the discomfort given to the user.

On the contrary, when the second control is switched to the first control, the control unit 100 may control so as to increase the magnitude of the light output output by the light source unit 110. As a result, the brightness of the virtual image visually recognized by the user can be kept constant even when the second control is switched to the first control. Therefore, it is possible to reduce the discomfort given to the user.

Then, when the sensing information indicates the first brightness, the control unit 100 displays the same type of image displayed at the same position in the virtual image regardless of the brightness indicated by the sensing information, and the sensing information has the second brightness. In biaxial scanning, an image enlarged along the axial direction in which the magnitude of the amplitude is reduced is generated in the scanning portion. Here, the same type of image is the same as described above.

The control of the light source unit 110 and the scanning unit 120 by the control unit 100 may be performed independently, but may include adjustments such as synchronization between the two. The control unit 100 may be configured by a computer system (not shown) including a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read-Only Memory), and the like. Some or all of the functions of the control unit 100 may be achieved by the CPU using the RAM as a working memory to execute a program recorded in the ROM. Further, some or all the functions of the control unit 100 may be achieved by a dedicated hardware circuit. The control unit 100 may be composed of a single component that performs centralized control, or may be composed of a plurality of components that perform distributed control in cooperation with each other. In the present embodiment, the control unit 100 is a component of the video display system 10, but may be a component of an external device.

Hereinafter, a specific example of control of the light source unit 110 and the scanning unit 120 by the control unit 100 will be described with reference to the drawings.

(First example)
First, the first example will be described.

FIG. 9 is a diagram showing an example of the magnitude of the amplitude of scanning by the scanning unit in the first control. FIG. 10 is a diagram showing a first example of the magnitude of the amplitude of scanning by the scanning unit in the second control.

The amplitude region 401 in the first control is, for example, a size reduced by a predetermined ratio according to the size of the screen 130. The amplitude region 402 in the second control is smaller than the amplitude region 401 in the first control, for example, 1 / of the region 401 in both the horizontal and vertical directions of scanning. It is the size of 2. The ratio to be reduced is not limited to 1/2, but may be 2/3, 3/4, or another ratio smaller than 1. In the second control, the control unit 100 scans the scanning unit 120 with the magnitude of both the horizontal axis direction and the vertical axis direction in the biaxial scanning, and the scanning unit 120 scans the laser beam as compared with the first control. It is reduced based on the center of the area to be used. That is, the region 402 on the screen 130 scanned by the scanning unit 120 with the laser beam in the second control includes the center of the region 401 on the screen 130 scanned by the scanning unit 120 with the laser beam in the first control, and the entire region includes the region 401. It overlaps 401 and is smaller than region 401 in both the horizontal and vertical axes.

FIG. 11 is a diagram showing a first example of the size of the image generated in the first control. FIG. 12 is a diagram showing a first example of the size of the image generated in the second control.

11 and 12 show an example of a priority image in which the priority of display to the user is set higher than that of other images. In FIGS. 11 and 12, an image region 410 having the maximum size that can be projected onto the screen 130 is shown, and priority images 411 and 412 in the image region 410 are shown, respectively. The image region 410 shown here is used by the light source unit 110 to control the laser beam. A numerical value from 0 to 800 in the horizontal axis direction corresponds to the time required for each unit scanning amount of the scanning unit 120. A numerical value from 0 to 600 in the vertical axis direction corresponds to the number of stages of raster scan in the vertical axis direction of scanning of the scanning unit 120.

The priority image is, for example, an image for displaying a warning to the user, and is an image for urging the user to perform an urgent operation such as applying a brake. The size of the priority image 412 generated by the control unit 100 in the second control is in the horizontal axis direction rather than the size of the priority image 411 generated by the control unit 100 in the first control even if the types of images to be displayed are the same. And large in both the vertical axis direction. Specifically, the size of the priority image 412 is twice as large as that of the priority image 411 in both the horizontal axis direction and the vertical axis direction.

Therefore, even if the temperature of the light source unit 110 is such that it is difficult to obtain a sufficient light output, the unit scanning amount can be reduced by reducing the scanning amplitude by the scanning unit 120 in both the horizontal axis direction and the vertical axis direction. The density of the hit laser light can be effectively improved. Therefore, it is possible to effectively suppress the reduction in the brightness of the priority image such as the image for displaying the warning displayed in the center.

The enlargement ratio of the image is the reciprocal of the reduction ratio of the magnitude of the amplitude to be reduced. In the second control, the control unit 100 enlarges the size of the priority image 412 in both the horizontal axis direction and the vertical axis direction with reference to the center of the priority image 411 generated in the first control. That is, the priority image 412 includes the center of the priority image 411 and is entirely overlapped with the priority image 411, and is larger than the priority image 412 in both the horizontal axis direction and the vertical axis direction.

(Second example)
Next, a second example will be described.

FIG. 13 is a diagram showing a second example of the magnitude of the amplitude of scanning by the scanning unit in the second control. In the second example, the magnitude of the amplitude of scanning by the scanning unit in the first control is the same as that shown in FIG.

In the second example, the amplitude region 403 in the second control is smaller than the amplitude region 401 in the first control, for example, in the horizontal axis direction of the scan, half of the region 401. It is the size. The ratio to be reduced is not limited to 1/2, but may be 2/3, 3/4, or another ratio smaller than 1. In the second control, the control unit 100 causes the scanning unit 120 to refer to the magnitude of the amplitude in the horizontal axis direction in the biaxial scanning with respect to the center of the region in which the scanning unit 120 scans the laser beam as compared with the case of the first control. Shrink as. That is, the region 403 on the screen 130 scanned by the scanning unit 120 with the laser beam in the second control includes the center of the region 401 on the screen 130 scanned by the scanning unit 120 with the laser beam in the first control, and the entire region includes the region 401. It overlaps 401 and is smaller in the horizontal axis direction than the region 402 and equal in the vertical axis direction.

FIG. 14 is a diagram showing a second example of the size of the image generated in the first control. FIG. 15 is a diagram showing a second example of the size of the image generated in the second control.

14 and 15 show an example of a constant image that is set to be constantly displayed when the vehicle 300 is in operation. In FIGS. 14 and 15, the image region 410 is shown as in FIGS. 11 and 12, and the constant images 413 and 414 in the image region 410 are shown, respectively.

The constant image is, for example, an image showing the operating state of the vehicle 300, such as an image showing the traveling path of the vehicle 300, an image showing the traveling speed, an image showing the fuel gauge, and an image showing the remaining amount of the battery. The size of the constant image 414 generated by the control unit 100 in the second control is in the horizontal axis direction rather than the size of the constant image 413 generated by the control unit 100 in the first control even if the types of images to be displayed are the same. Is big in. Specifically, the size of the constant image 414 is a size that is twice as large as the constant image 413 in the horizontal axis direction.

Therefore, even if the temperature of the light source unit 110 is such that it is difficult to obtain sufficient light output, the density of laser light per unit scanning amount is reduced by reducing the amplitude of scanning by the scanning unit 120 in the horizontal axis direction. Can be effectively improved. Therefore, since the virtual image can be displayed in the area extending in the vertical axis direction, the size of the constant image, which is often displayed in the lower part of the display area D, such as the image showing the operating state of the moving body, is almost changed. It is possible to effectively suppress the constant reduction in the brightness of the image without causing the image to be reduced.

The enlargement ratio of the image is the reciprocal of the reduction ratio of the magnitude of the amplitude to be reduced, as in the first example. In the second control, the control unit 100 enlarges the size of the constant image 414 in the horizontal axis direction with reference to the center of the constant image 413 generated in the first control. That is, the constant image 414 includes the center of the constant image 413 and is entirely overlapped with the constant image 413, and is larger than the constant image 414 in the horizontal axis direction.

(Third example)
Next, a third example will be described.

FIG. 16 is a diagram showing a third example of the magnitude of the amplitude of scanning by the scanning unit in the second control. In the third example, the magnitude of the amplitude of scanning by the scanning unit in the first control is the same as that shown in FIG.

In the third example, the amplitude region 404 in the second control is smaller than the amplitude region 401 in the first control, for example, ½ of the region 401 in the vertical axis direction of the scan. It is the size. The ratio to be reduced is not limited to 1/2, but may be 2/3, 3/4, or another ratio smaller than 1. In the second control, the control unit 100 causes the scanning unit 120 to refer to the magnitude of the amplitude in the vertical axis direction in the biaxial scanning with respect to the center of the region in which the scanning unit 120 scans the laser beam as compared with the case of the first control. Shrink as. That is, the region 404 on the screen 130 scanned by the scanning unit 120 with the laser beam in the second control includes the center of the region 401 on the screen 130 scanned by the scanning unit 120 with the laser beam in the first control, and the entire region includes the region 401. It overlaps 401 and is smaller in the horizontal axis direction than the region 402 and equal in the vertical axis direction.

FIG. 17 is a diagram showing a third example of the size of the image generated in the first control. FIG. 18 is a diagram showing a third example of the size of the image generated in the second control.

17 and 18 are peripheral displays set to be displayed near one end in the horizontal axis direction of a region on the screen 130 scanned by the scanning unit 120 when the sensing information indicates within a predetermined temperature range. An example image is shown. In FIGS. 17 and 18, the image region 410 is shown as in FIGS. 11 and 12, and the peripheral display images 415 and 416 in the image region 410 are shown, respectively.

The peripheral display image is, for example, an image showing an object on the left or right of the course of the vehicle 300. Here, the object is a person, a vehicle, an obstacle, a sign, or the like. The size of the peripheral display image 416 generated by the control unit 100 in the second control is perpendicular to the size of the peripheral display image 415 generated by the control unit 100 in the first control even if the types of images to be displayed are the same. Large in the axial direction. Specifically, the size of the peripheral display image 416 is a size that is twice as large as the peripheral display image 415 in the vertical axis direction.

Therefore, even if the temperature of the light source unit 110 is such that it is difficult to obtain sufficient light output, the density of laser light per unit scanning amount is reduced by reducing the amplitude of scanning by the scanning unit 120 in the vertical axis direction. Can be effectively improved. Therefore, the brightness of the peripheral display image is reduced with almost no change in the size of the peripheral display image such as an image showing an object on the left or right of the path of the moving object, which is easily displayed at the left and right edges. Can be effectively suppressed.

The enlargement ratio of the image is the reciprocal of the reduction ratio of the magnitude of the amplitude to be reduced, as in the first example and the second example. In the second control, the control unit 100 enlarges the size of the peripheral display image 416 in the vertical axis direction with reference to the center of the peripheral display image 415 generated in the first control. That is, the peripheral display image 416 includes the center of the peripheral display image 415 and is entirely overlapped with the peripheral display image 416, and is larger than the peripheral display image 416 in the horizontal axis direction.

[1-3. Operation of video display system]
Next, the operation of the video display system will be described.

FIG. 19 is a flowchart showing an example of the basic operation of the video display system.

The control unit 100 generates an image signal indicating an image projected on the screen in order to display a virtual image to the user of the vehicle 300 (S11).

Next, the control unit 100 controls the light source unit 110 and the scanning unit 120 according to the generated image signal (S12). The control unit 100 controls the light source unit 110 to emit the laser beam to the light source unit 110, and also controls the scanning unit 120 to scan the laser beam on the screen 130 in two axes to display a virtual image to the user of the vehicle 300. The image to be used is projected on the screen 130.

Next, the amplitude adjustment control performed during the basic operation of the video display system will be described.

FIG. 20 is a flowchart showing a first example of amplitude adjustment control of a video display system.

The control unit 100 acquires the temperature of the light source unit 110 detected by the temperature sensor 140 (S21).

The control unit 100 determines whether or not the acquired temperature of the light source unit 110 is within a predetermined temperature range (S22).

When the control unit 100 determines that the temperature of the light source unit 110 is within a predetermined temperature range (Yes in S22), the control unit 100 performs the first control (S23).

On the other hand, when the temperature of the light source unit 110 is determined to be outside the predetermined temperature range (No in S22), the control unit 100 performs the second control (S24).

FIG. 21 is a flowchart showing a second example of amplitude adjustment control of the video display system.

The control unit 100 acquires the brightness of the outside world of the vehicle 300 detected by the illuminance sensor 150 (S31).

The control unit 100 determines whether or not the acquired brightness of the outside world of the vehicle 300 is equal to or less than a predetermined threshold value (S32).

When it is determined that the brightness of the outside world of the vehicle 300 is equal to or less than a predetermined threshold value (Yes in S32), the control unit 100 performs the first control (S33).

On the other hand, when it is determined that the brightness of the outside world of the vehicle 300 is larger than a predetermined threshold value (No in S32), the control unit 100 performs the second control (S34).

The first control and the second control of the amplitude adjustment control may be executed in parallel. In this case, if either the determination in step S22 is determined as No or the determination in step S32 as No, the second control is performed.

FIG. 22 is a flowchart showing an example of the second control of the video display system.

In the second control, the control unit 100 determines whether or not the generated image includes a priority image (S41).

When it is determined that the priority image is included (Yes in S41), the control unit 100 reduces the scanning amplitude in both the horizontal axis direction and the vertical axis direction, and reduces the scanning amplitude in both the horizontal axis direction and the vertical axis direction. An enlarged image is generated in both directions (S42). That is, the second control in the first example described with reference to FIGS. 9 to 12 is performed.

On the other hand, when it is determined that the priority image is not included (No in S41), the control unit 100 determines whether or not the generated image includes a peripheral display image (S43).

When it is determined that the peripheral display image is included (Yes in S43), the control unit 100 reduces the scanning amplitude in the vertical axis direction and generates an enlarged image in the vertical axis direction (S44). .. That is, the second control in the third example described with reference to FIGS. 9 and 16 to 18 is performed.

On the other hand, when it is determined that the peripheral display image is not included (No in S43), the control unit 100 reduces the scanning amplitude in the horizontal axis direction and generates an enlarged image in the horizontal axis direction. (S45). That is, the second control in the second example described with reference to FIGS. 9 and 13 to 15 is performed.

In the second control, the control described with reference to FIG. 22 does not have to be performed, and any of the first example, the second example, and the third example may be performed.

[1-4. Effect etc.]
According to the image display system 10 according to the present embodiment, when the sensing information by the temperature sensor 140 indicates a temperature outside the predetermined temperature range, the control unit 100 tells the scanning unit 120 at least one axis in the biaxial scanning. The magnitude of the amplitude in the direction is reduced compared to when the sensing information indicates a temperature within a predetermined temperature range. Therefore, even if the temperature of the light source unit 110 is such that it is difficult to obtain sufficient light output, the density of laser light per unit scanning amount can be improved by reducing the amplitude of scanning by the scanning unit 120. Can be done. Therefore, the brightness of the virtual image is supplemented, and a clear image can be displayed. Further, since the brightness of the image can be adjusted without adjusting the temperature, it is possible to adjust the brightness of the image with responsiveness.

Further, in the image display system 10 according to the present embodiment, when the sensing information indicates a temperature outside the predetermined temperature range, the control unit 100 is displayed at the same position in the virtual image regardless of the temperature indicated by the sensing information. In biaxial scanning, the scanning unit is made to generate an enlarged image of the type of image along the axial direction in which the magnitude of the amplitude is reduced, as compared with the case where the sensing information indicates a temperature within a predetermined temperature range. Therefore, even when the brightness of the virtual image is supplemented by reducing the amplitude of scanning by the scanning unit 120, it is possible to suppress the reduction in the size of the virtual image.

Further, in the video display system 10 according to the present embodiment, the enlargement ratio of the generated image is the reciprocal of the reduction ratio of the magnitude of the amplitude to be reduced. Therefore, even when the brightness of the virtual image is supplemented by reducing the amplitude of scanning by the scanning unit 120, the size of the virtual image can be made equal to the size before the amplitude is reduced.

Further, according to the image display system 10 according to the present embodiment, when the sensing information by the illuminance sensor 150 indicates the first brightness, the control unit 100 tells the scanning unit 120 at least one axis in the biaxial scanning. The magnitude of the directional amplitude is reduced compared to when the sensing information indicates a second brightness that is darker than the first brightness. Therefore, even under conditions where the outside world is brighter than a predetermined threshold value and the contrast between the virtual image and the actual scene is likely to decrease, the laser per unit scanning amount can be reduced by reducing the amplitude of scanning by the scanning unit 120. The density of light can be improved. Therefore, the brightness of the virtual image is supplemented, and a clear image can be displayed. Therefore, it is possible to prevent the user from deteriorating the visibility of the virtual image.

[1-5. Modification example]
In the above embodiment, the illuminance sensor 150 is used to detect the brightness of the outside world of the vehicle 300, but the illuminance sensor 150 is not limited to the use. For example, the brightness of the outside world of the vehicle 300 may be detected by using a device having an image sensor such as a camera.

In the above embodiment, either the first control or the second control is selectively performed depending on whether or not the temperature detected by the temperature sensor 140 is within a predetermined temperature range. That is, in the above embodiment, the two-step control is performed in two steps of whether or not the condition is satisfied, but the present invention is not limited to this, and it is determined whether or not the multi-step condition is satisfied, and the multi-step control is performed. Control may be performed.

The multi-step condition includes, for example, a first temperature range, a second temperature range, and a third temperature range. The first temperature range is a temperature range in which the light output from the light source unit 110 is sufficient. The second temperature range is a temperature range in which the light output from the light source unit 110 is smaller than that of the first temperature range. The third temperature range is a temperature range in which the light output from the light source unit 110 is smaller than the second temperature range. The second temperature range is composed of an upper limit value of the first temperature range to a temperature range of the first temperature range and a lower limit value of the first temperature range to a temperature range of the second temperature range. The third temperature range is a temperature range larger than the upper limit of the temperature range of the first temperature range of the first temperature range and a temperature smaller than the adjustment of the temperature range of the second temperature range of the first temperature range. Consists of a range.

In this case, the control unit 100 performs the first control when the temperature detected by the temperature sensor 140 is within the first temperature range. When the detected temperature is within the second temperature range, the control unit 100 performs the third control in which the amplitude of the scanning unit 120 is smaller than that of the first control. In the third control, the control unit 100 may enlarge the generated image as in the second control in the above embodiment. When the detected temperature is within the third temperature range, the control unit 100 performs the fourth control in which the amplitude is made smaller by the scanning unit 120 than in the third control. In the fourth control, the control unit 100 may enlarge the generated image as in the second control in the above embodiment. In the fourth control, the control unit 100 generates an image that is further enlarged than the image generated in the third control.

In the above embodiment, the control that selectively performs one of the first control and the second control according to the temperature detected by the temperature sensor 140 and the brightness of the outside world detected by the illuminance sensor 150 are used. Correspondingly, both the first control and the control that selectively performs one of the second controls are performed, but only one of them may be performed.

[1-6. Others]
The video display system according to the embodiment has been described above as an example of the technology disclosed in the present application, but the present disclosure is not limited to the embodiment. The techniques in the present disclosure can also be applied to modified examples or other embodiments of embodiments that have been modified, replaced, added, omitted, etc., as appropriate. It is also possible to combine the components described in the embodiments into a new embodiment or modification.

As mentioned above, the comprehensive or specific embodiments of the present disclosure may be implemented in recording media such as systems, methods, integrated circuits, computer programs or computer readable CD-ROMs. In addition, the comprehensive or specific aspects of the present disclosure may be realized by any combination of systems, methods, integrated circuits, computer programs and recording media.

For example, each processing unit included in the video display system according to the above embodiment is typically realized as an LSI (Large Scale Integration: Large Scale Integration) which is an integrated circuit. These may be individually integrated into one chip, or may be integrated into one chip so as to include a part or all of them.

Further, the integrated circuit is not limited to the LSI, and may be realized by a dedicated circuit or a general-purpose processor. An FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connection and settings of circuit cells inside the LSI may be used.

In the above embodiment, each component may be configured by dedicated hardware or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or a processor reading and executing a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

Further, the division of the functional block in the block diagram is an example, and a plurality of functional blocks can be realized as one functional block, one functional block can be divided into a plurality of functional blocks, and some functions can be transferred to other functional blocks. You may. Further, the functions of a plurality of functional blocks having similar functions may be processed by a single hardware or software in parallel or in a time division manner.

The video display system according to one aspect has been described above based on the embodiment, but the present disclosure is not limited to the embodiment. As long as the gist of the present disclosure is not deviated, a form in which various modifications conceived by those skilled in the art are applied to the embodiment and a form constructed by combining components in different embodiments are also included in the scope of one embodiment. You may.

The present disclosure can be used for an image display system or the like that can suppress a decrease in visibility of a virtual image by a user.

10 Video display system 100 Control unit 110 Light source unit 120 Scan unit 130 Screen 140 Temperature sensor 150 Illuminance sensor 160 Optical system 160a First reflector 160b Second reflector 200 Display medium 201 Windshield (display medium)
300 vehicles (mobile)
301 dashboard

Claims (12)

It is an image display system that is mounted on a moving body and allows the user of the moving body to visually recognize the image projected on the screen as a virtual image.
A screen on which an image visually recognized by the user as a virtual image is projected, and
A light source that emits laser light and
A scanning unit that scans the laser beam on the screen in two axes and projects the image onto the screen.
The brightness of the outside world of the moving body is measured by controlling the light source unit by using an image signal for generating the image and projecting the generated image onto the screen with the laser beam. It is provided with a control unit that receives input of sensing information indicating a laser and controls the scanning unit according to the brightness indicated by the sensing information.
When the sensing information indicates the first brightness, the control unit informs the scanning unit of the magnitude of the amplitude in at least one axial direction in the biaxial scanning, and the sensing information is darker than the first brightness. An image display system that reduces the brightness compared to when it shows the second brightness. When the sensing information indicates the first brightness, the control unit displays the same type of image displayed at the same position in the virtual image regardless of the brightness indicated by the sensing information, and the sensing information indicates the first brightness. The image display system according to claim 1, wherein an image enlarged along an axial direction in which the magnitude of the amplitude is reduced in the scanning portion in the two-axis scanning is generated rather than when the brightness of the second is shown. The video display system according to claim 2, wherein the enlargement ratio of the generated image is the reciprocal of the reduction ratio of the magnitude of the amplitude to be reduced. When the sensing information indicates the first brightness, the control unit informs the scanning unit of the magnitude of both the horizontal axis direction and the vertical axis direction in the biaxial scanning, and the sensing information indicates the second brightness. The scanning unit is reduced in size with respect to the center of the region where the laser beam is scanned, as compared with the case of showing the brightness of.
The image display system according to claim 2 or 3, wherein the image projected on the screen includes a priority image in which the priority of display to the user is set higher than that of other images. The video display system according to claim 4, wherein the priority image is an image for displaying a warning to the user. When the sensing information indicates the first brightness, the control unit indicates to the scanning unit the magnitude of the amplitude in the horizontal axis direction in the biaxial scanning, and when the sensing information indicates the second brightness. Rather than reducing the area in which the scanning unit scans the laser beam with reference to the center in the horizontal axis direction.
The image display system according to claim 2 or 3, wherein the image projected on the screen includes a constantly displayed image that is set to be constantly displayed when the moving body is in operation. The video display system according to claim 6, wherein the constantly displayed image is an image showing an operating state of the moving body. When the sensing information indicates the first brightness, the control unit indicates to the scanning unit the magnitude of the amplitude in the vertical axis direction in the biaxial scanning, and when the sensing information indicates the second brightness. Rather than reducing the area in which the scanning unit scans the laser beam with reference to the center in the vertical axis direction.
It is set that the image projected on the screen is displayed near one end in the horizontal axis direction of the region on the screen scanned by the scanning unit when the sensing information indicates the second brightness. The image display system according to claim 2 or 3, which includes a peripheral display image. The video display system according to claim 8, wherein the peripheral display image is an image showing an object on the left or right of the path of the moving body. It is a video display method executed by a video display system that is mounted on a moving body and projects an image on a screen so that the user of the moving body can visually recognize it as a virtual image.
Generates an image signal indicating the image projected onto the screen.
A laser beam is emitted according to the generated image signal,
The laser beam is biaxially scanned on the screen, and the image visually recognized as the virtual image by the user of the moving body is projected on the screen.
Obtaining sensing information indicating the brightness of the outside world of the moving body measured using a sensor,
When the sensing information indicates the first brightness, the magnitude of the amplitude in at least one axial direction in the biaxial scanning is larger than when the sensing information indicates the second brightness which is darker than the first brightness. Video display method that also reduces. A program for causing a computer to execute the video display method according to claim 10. A mobile body including the video display system according to any one of claims 1 to 9.

Images