Display device and display system

Abstract

A display device according to the present disclosure comprises: an image generation unit that generates an image; an optical system that projects the image, as image light, to a transmission / reflection unit, and that displays a virtual image; and a control unit that causes a notification image, for notification, to be displayed in a band-shaped region on the lower edge of the virtual image.

Description

Display device and display system

[0001] The present invention relates to a display device and a display system.

[0002] Patent Document 1 describes that when the vehicle speed exceeds the speed limit, a graphic of the speed limit is highlighted (for example, alternately displayed in reverse and non-reversed) on the head-up display.

[0003] WO2020 / 066837 publication

[0004] The purpose of notifications such as exceeding the speed limit is to alert the driver, but if the notifications are displayed near the driver's point of gaze, they may be annoying to the driver.

[0005] The present invention aims to solve the conflicting problems of calling the driver's attention and suppressing discomfort to the driver.

[0006] One form of the present invention for achieving the above object is a display device comprising an image generation unit that generates an image, an optical system that projects the image as image light onto a transmissive-reflecting unit and displays a virtual image, and a control unit that displays a notification image for notification in a strip-shaped region at the bottom edge of the virtual image.

[0007] Other problems and solutions disclosed in the present application will be made clear in the detailed description and drawings.

[0008] According to the present invention, it is possible to call the driver's attention while suppressing discomfort felt by the driver.

[0009] FIG. 1 is an explanatory diagram of a display device 10. FIG. 2 is a block diagram of the display device 10. FIG. 3 is an explanatory diagram of a display screen 41 that is displayed as a virtual image 40. FIG. 4A is an explanatory diagram of an example of the display screen 41. FIG. 4B is an explanatory diagram of the display screen 41 that includes a notification image 44. FIG. 5 is a table showing the relationship between the type of notification and the color (notification color) of the notification image 44. FIG. 6 is an explanatory diagram of a modified display device 10.

[0010] <Cross-reference to related applications> This application claims priority to Japanese patent application No. 2023-115873, filed on July 14, 2023, the contents of which are incorporated by reference.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, identical or similar components may be designated by common reference numerals, and redundant description may be omitted.

[0012] ===Embodiment=== <Configuration> Fig. 1 is an explanatory diagram of a display device 10. Fig. 2 is a block diagram of the display device 10.

[0013] The display device 10 is a device that displays an image to a driver. The display device 10 is a so-called head-up display (HUD) device. The display device 10 displays an image (virtual image 40) superimposed on an actual background within the driver's field of vision. The figure shows the display device 10 projecting image light onto a windshield (front glass) to display the virtual image 40 on the windshield. However, the transflective unit 20 that displays the virtual image 40 is not limited to the windshield and may be a combiner installed inside the vehicle. The display device 10 includes an image generating unit 11, an optical system 12, and a control unit 13. The display system 100 is a system that adds the transflective unit 20 to the display device 10 (which includes the image generating unit 11, the optical system 12, and the control unit 13).

[0014] The image generation unit 11 is a device that generates an image. The image generation unit 11 is configured by, for example, a liquid crystal display device, an organic EL display device, a micro LED display device, or a projector device using a laser light source. The image generation unit 11 generates an image based on a signal (image signal) from the control unit 13. The image generated by the image generation unit 11 is irradiated onto the optical system 12 as image light.

[0015] The optical system 12 projects the image generated by the image generation unit 11 onto the transmission / reflection unit 20 as image light. The optical system 12 is composed of one or more optical elements. The optical elements constituting the optical system 12 include, for example, lenses, mirrors, and prisms. The optical system 12 is configured to display a virtual image 40 to the driver. The optical system 12, together with the transmission / reflection unit 20, constitutes an imaging optical system that allows the driver to visually recognize the virtual image 40. For this reason, the optical system 12 is designed in consideration of the optical characteristics of the transmission / reflection unit 20.

[0016] The transmissive reflector 20 reflects the image light from the optical system 12 while transmitting light from outside the vehicle. The transmissive reflector 20 functions as a so-called half mirror. In this example, the transmissive reflector 20 is a windshield (front glass). However, the transmissive reflector 20 may also be a combiner installed inside the vehicle. The transmissive reflector 20 forms a virtual image 40 by reflecting the image light from the optical system 12. The driver visually recognizes a background that is visible due to the transmission of light through the transmissive reflector 20 and a virtual image 40 (spatial image) that is visible due to the reflection of the image light by the transmissive reflector 20, superimposed on each other.

[0017] The control unit 13 is responsible for controlling the display device 10. The control unit 13 outputs an image signal to the image generation unit 11, causing the image generation unit 11 to generate an image. The image generation unit 11 generates an image in accordance with the image signal from the control unit 13. In this way, the control unit 13 controls the image generation unit 11 via the image signal.

[0018] The control unit 13 acquires a detection signal from the detection unit 30. The detection unit 30 detects physical quantities indicative of the external situation and outputs the detection result as a detection signal to the control unit 13. The detection unit 30 includes, for example, a vehicle speed detection unit (e.g., a vehicle speed sensor) that detects the vehicle speed, a ranging device such as LiDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), and a position detection unit (e.g., a GPS (Global Positioning System) module) that detects the current location. Note that the detection unit 30 includes not only a conversion element such as a sensor that detects physical quantities and converts them into a detection signal, but also a device (e.g., an EUC) that converts the sensor output signal and outputs another signal (detection signal). As will be described later, the control unit 13 outputs an image signal corresponding to the detected situation based on the detection signal from the detection unit 30. Furthermore, the control unit 13 determines whether a notification is necessary based on the detection signal from the detection unit 30, and if a notification is necessary, generates an image signal for displaying a notification image 44 (described later).

[0019] The control unit 13 includes an image processing unit 14 and a determination unit 15. The image processing unit 14 generates an image signal to be output to the image generation unit 11. The determination unit 15 determines the external situation based on a detection signal from the detection unit 30. The determination unit 15 also determines whether or not a notification is required when a vehicle ahead starts moving or when the speed limit is exceeded based on the detection signal from the detection unit 30. The image processing unit 14 outputs an image signal according to the determination result of the determination unit 15. The processing of the image processing unit 14 and the determination unit 15 will be described later.

[0020] The control unit 13 is configured by a computer equipped with an arithmetic processing unit such as a CPU or an MPU and storage devices (main storage device and auxiliary storage device) such as a RAM or a ROM. Each process performed by the control unit 13 (each process performed by the image processing unit 14 and the determination unit 15) is realized by the arithmetic processing unit executing a program stored in the storage device.

[0021] <Regarding Notification Image> FIG. 3 is an explanatory diagram of a display screen 41 on which a virtual image 40 is displayed.

[0022] The display screen 41 is a screen (image) that the display device 10 displays as the virtual image 40. The display screen 41 is a screen that is projected in the area of ​​the virtual image 40, and is visually perceived by the driver as being located outside the transmissive-reflecting unit 20 (outside the vehicle). The dotted line area in FIG. 3 indicates the area in which the display screen 41 is displayed. In other words, the dotted line area in FIG. 3 indicates the area of ​​the virtual image 40 shown in FIG. 1 and indicates the area that the display device 10 can display. The display device 10 displays the display screen 41 showing various information within the dotted line area in FIG. 3. That is, the control unit 13 (image processing unit 14) outputs image signals for displaying various information on the display screen 41 to the image generation unit 11, and causes the image generation unit 11 to generate images for displaying the display screen 41. In the following description, the display screen 41 that is projected as the virtual image 40 will be mainly described, and a description of the images generated by the image generation unit 11 will be omitted.

[0023] Fig. 4A is an explanatory diagram of an example of the display screen 41. Fig. 4A shows the display screen 41 when no notification is being made.

[0024] As shown in FIG. 4A , various pieces of information are displayed on the display screen 41. In the following description, images showing various pieces of information on the display screen 41 may be referred to as "information images 42." Note that FIG. 4A shows an example of the display screen 41 and information images 42 (42A-42F), and the display screen 41 and information images 42 are not limited to those shown in FIG. 4A . For example, information images other than the information images 42 (42A-42F) shown in FIG. 4A may be displayed on the display screen 41. Furthermore, any of the information images 42 (42A-42F) shown in FIG. 4A may not be displayed on the display screen 41. Furthermore, not all of the information images 42 (42A-42F) shown in FIG. 4A may be displayed on the display screen 41 (for example, only a notification image 44, described below, may be displayed on the display screen 41).

[0025] The display screen 41 shown in FIG. 4A includes information images 42 such as a vehicle speed image 42A, a shift position image 42B, a road sign image 42C, an indicator bar image 42D, a driving assistance image 42E, and a navigation image 42F.

[0026] The vehicle speed image 42A is an image showing vehicle speed information. The control unit 13 acquires vehicle speed information from the detection unit 30 and displays the display screen 41 including the vehicle speed image 42A. The shift position image 42B is an image showing a shift position (e.g., P, R, N, D, etc.). The control unit 13 acquires shift position information from the ECU functioning as the detection unit 30 and displays the display screen 41 including the shift position image 42B. The road sign image 42C is an image showing a road sign. For example, the detection unit 30 includes a camera that captures images of the front and an image analysis unit. The image analysis unit analyzes the camera's captured image data to detect road signs and outputs a detection signal showing road sign information to the control unit 13. The control unit 13 acquires road sign information from the detection unit 30 and displays the display screen 41 including the road sign image 42C. The indicator bar image 42D is an image that displays the indicator measurement results as a bar. The control unit 13 acquires information indicating the measurement results from the detection unit 30 (e.g., an ECU or indicator) and displays the display screen 41 including an indicator bar image 42D. The driving assistance image 42E is an image indicating the status of the driving assistance system. For example, the driving assistance system includes a lane keeping function and a following driving function, and the driving assistance image 42E includes an image of a lane indicating that the lane keeping function is operating, and an image indicating the set speed and following distance set in the following driving function. The control unit 13 acquires information about the driving assistance system from the detection unit 30 (e.g., an ECU) and displays the display screen 41 including the driving assistance image 42E. The navigation image 42F is an image indicating navigation information. The control unit 13 acquires navigation information from a car navigation device functioning as the detection unit 30 and displays the display screen 41 including the navigation image 42F.

[0027] Fig. 4B is an explanatory diagram of the display screen 41 including the notification image 44. Fig. 4B shows the display screen 41 during notification. The display screen 41 during notification is a screen in which the notification image 44 is added to the display screen 41 during non-notification (see Fig. 4A).

[0028] The notification image 44 is an image for notifying the driver. The notification image 44 is an image (information image) for displaying information (notification information) for drawing the driver's attention. The notification image 44 is an image that is additionally displayed on the non-notification display screen 41 (see FIG. 4A ) when it is necessary to draw the driver's attention.

[0029] 4B , the notification image 44 is displayed in a strip-like region at the bottom of the display screen 41 (virtual image 40). The control unit 13 (image processing unit 14) causes the image generation unit 11 to display an image such that the notification image 44 is displayed in the strip-like region at the bottom of the virtual image 40.

[0030] Here, the "lower edge" refers to a portion (area) near the edge (lower edge) that constitutes the lower edge. Also, "near" the lower edge means closer to the lower edge than the center in the vertical direction. In other words, the "lower edge" of the display screen 41 (virtual image 40) refers to a portion (area) that is the lower quarter of the display screen 41 (virtual image 40). The notification image 44 is displayed on the lower edge of the display screen 41 (virtual image 40), and therefore is displayed in the lower quarter of the area of ​​the display screen 41 (virtual image 40).

[0031] The lower edge of the notification image 44 shown in FIG. 4B is in contact with the lower side of the display screen 41 (virtual image 40). However, blank pixels may exist between the lower edge of the notification image 44 and the lower side of the display screen 41 (virtual image 40). The upper edge of the notification image 44 is located closer to the lower side of the display screen 41 (virtual image 40) than the vertical center. In the case of the display screen 41 shown in FIG. 4B, at least the area between another information image 42 (e.g., the indicator bar image 42D or the driving assistance image 42E located at the bottom) and the lower side of the display screen 41 (virtual image 40) corresponds to the lower side. Furthermore, in the case of the display screen 41 shown in FIG. 4B, at least a portion of the notification image 44 is displayed in the area between another information image 42 (e.g., the indicator bar image 42D or the driving assistance image 42E located at the bottom) and the lower side of the display screen 41 (virtual image 40).

[0032] Furthermore, the term "strip-shaped region" refers to a region having an elongated (strip-like) shape. Since the notification image 44 is displayed in a strip-shaped region at the bottom edge of the display screen 41 (virtual image 40), the notification image 44 is an elongated image extending in the left-right direction. The left and right edges of the notification image 44 shown in FIG. 4B are in contact with the left and right edges of the display screen 41 (virtual image 40), respectively. However, blank pixels may exist between the left edge of the notification image 44 and the left edge of the display screen 41 (virtual image 40), and blank pixels may exist between the right edge of the notification image 44 and the right edge of the display screen 41 (virtual image 40).

[0033] Because the notification image 44 is a long image extending in the left-right direction, it is an image that is easily noticeable to the driver when it appears on the display screen 41. On the other hand, because the notification image 44 is positioned at the bottom of the display screen 41 (virtual image 40), the angle between the line connecting the driver's eyes and the notification image 44 and the driver's line of sight (the line connecting the driver's eyes and the point of gaze while driving) can be increased, thereby reducing the discomfort felt by the driver when it appears on the display screen 41. Because the notification image 44 represents color, unlike when the driver is required to visually recognize letters or marks, the driver can notice the notification image 44 even if the angle between the line connecting the driver's eyes and the notification image 44 and the driver's line of sight is large. In this way, in this embodiment, the control unit 13 (image processing unit 14) displays the notification image 44 in a strip-shaped region at the bottom of the display screen 41 (virtual image 40), thereby solving the conflicting problems of alerting the driver and reducing discomfort felt by the driver.

[0034] The width (vertical dimension) of the notification image 44 is set to be relatively narrow. Unlike the vehicle speed image 42A and the road sign image 42C, the notification image 44 does not represent letters (including numbers) or marks, but represents a predetermined color. Therefore, the notification image 44 can be displayed in a smaller area than the other information images 42, and can still perform its notification function even when displayed in a small area. Therefore, for example, the width of the notification image 44 can be set to be narrower than the vertical dimension of the vehicle speed image 42A and the road sign image 42C. By setting the width (vertical dimension) of the notification image 44 to be narrow, it is possible to prevent the driver from feeling uncomfortable when the notification image 44 appears on the display screen 41.

[0035] 4A is composed of a predetermined color (single color), and the displayed area of ​​the notification image 44 is composed of the same color. However, the notification image 44 may be composed of a gradation image in which the density (brightness) of a single color (same hue) is gradually changed in the left-right direction.

[0036] In this embodiment, the control unit 13 (image processing unit 14) displays the notification image 44 by flashing it. The flashing of the notification image 44 can strongly draw the driver's attention. Note that since the notification image 44 represents a predetermined color, there is an advantage in that the flashing of the notification image 44 is less likely to annoy the driver than when an information image 42 such as a letter or a mark is flashed.

[0037] Instead of blinking the notification image 44, the control unit 13 may continuously display the notification image 44 (or keep the notification image 44 lit). In addition, if the notification image 44 is configured as a gradation image, the control unit 13 may animate the notification image 44 so that the shade moves in the left-right direction. This gives movement to the notification image 44, making it easier for the driver to notice the notification.

[0038] If the notification image 44 is displayed for a long period of time, it may cause strong discomfort to the driver. For this reason, the control unit 13 (image processing unit 14) may display the notification image 44 for a predetermined time (e.g., 10 seconds) and then remove the notification image 44 from the display screen 41 after the predetermined time has elapsed. Alternatively, the control unit 13 may flash the notification image 44 a predetermined number of times (e.g., 10 times) and then remove the notification image 44 from the display screen 41 after the predetermined number of flashes. This reduces discomfort to the driver.

[0039] The control unit 13 (image processing unit 14) displays the notification image 44 in different colors depending on the type of notification. Fig. 5 is a table showing the relationship between the type of notification and the color (notification color) of the notification image 44.

[0040] When notifying the user that a vehicle ahead has started moving, the control unit 13 displays an amber notification image 44. For example, the control unit 13 (determination unit 15) acquires vehicle speed information and distance information to the vehicle ahead from the detection unit 30 (e.g., a vehicle speed detection unit or LiDAR), and determines that a notification of the vehicle ahead is necessary if the user's own vehicle continues to be stopped even after a predetermined time (e.g., three seconds) has elapsed since the vehicle ahead started moving after the user's own vehicle stopped together with the vehicle ahead. If a notification of the vehicle ahead is necessary, the control unit 13 (image processing unit 14) displays the amber notification image 44 in a strip-shaped region at the bottom edge of the virtual image 40.

[0041] When notifying the driver that the speed limit has been exceeded, the control unit 13 displays a red notification image 44. For example, the control unit 13 (determination unit 15) acquires vehicle speed information and road sign information from the detection unit 30 and determines that a speed limit exceeding notification is necessary if the vehicle speed exceeds the speed limit by 10% or more. If a speed limit exceeding notification is necessary, the control unit 13 (image processing unit 14) displays a red notification image 44 in a strip-shaped region at the bottom of the virtual image 40. The control unit 13 may increase the blinking speed of the notification image 44 the more the vehicle speed exceeds the speed limit. Since increasing the blinking speed can strongly alert the driver, it is effective to change the speed of the notification image 44 depending on the vehicle speed when notifying the driver that the speed limit has been exceeded. Alternatively, the control unit 13 may increase the brightness of the notification image 44 the more the vehicle speed exceeds the speed limit.

[0042] When the follow-up driving function of the driving assistance system is activated, the control unit 13 displays a green notification image 44. For example, the control unit 13 (determination unit 15) acquires information about the driving assistance system from the detection unit 30 (e.g., ECU) and determines whether the follow-up driving function is activated. When notifying the driver that the follow-up driving function is activated, the control unit 13 (image processing unit 14) displays a green notification image 44 in a strip-shaped region at the bottom of the virtual image 40. Note that, in the case of a high-urgency notification, a red or amber notification image 44 is displayed, whereas in the case of a low-urgency notification, a green notification image 44 is displayed. The low-urgency notification image 44 may blink at a slower rate than the high-urgency notification image 44. This reduces discomfort to the driver.

[0043] When notifying the driver of detected drowsiness, the control unit 13 displays a blue notification image 44. For example, the detection unit 30 includes a camera that captures an image of the driver and an image analysis unit, and the image analysis unit analyzes the driver's eye movements based on the camera's image data to detect the driver's drowsiness and outputs a detection signal to the control unit 13. The control unit 13 (determination unit 15) acquires information about drowsiness from the detection unit 30 and determines whether or not a notification of detected drowsiness is necessary. If a notification of detected drowsiness is necessary, the control unit 13 (image processing unit 14) displays a blue notification image 44 in a strip-shaped region at the bottom of the virtual image 40. Note that blue light has an awakening effect, so by having the control unit 13 display the blue notification image 44 when drowsiness is detected, not only can the control unit 13 notify the driver that drowsiness has been detected, but also the control unit 13 can suppress the driver's drowsiness.

[0044] As shown in FIG. 5 , the control unit 13 (image processing unit 14) displays a notification image 44 of a different color according to the type of notification in a strip-shaped region at the bottom of the display screen 41 (virtual image 40). Because the color of the notification image 44 varies depending on the type of notification, the driver can distinguish the content of the notification by the color of the notification image 44. In addition, because the notification image 44 is displayed in the same location, it becomes easier for the driver to notice the notification. Note that the types of notifications are not limited to those shown in FIG. 5 , and other types of notifications may be provided. Furthermore, the color of the notification image 44 is not limited to that shown in FIG. 5 , and other colors may be used.

[0045] Incidentally, when alerting the driver of a preceding vehicle's departure or exceeding the speed limit, a warning sound may be emitted from a speaker (not shown). However, the warning sound may be very unpleasant to the driver. For this reason, it is desirable for the control unit 13 (image processing unit 14) to display a notification screen on the display screen 41 (virtual image 40) before the warning sound is emitted. For example, if a warning sound is set to be emitted five seconds after the preceding vehicle has started moving, the control unit 13 displays an amber notification image 44 indicating the preceding vehicle's departure three seconds after the preceding vehicle has started moving. This allows the driver to be alerted before the warning sound is emitted, and if the driver responds immediately, the warning sound does not need to be emitted, thereby preventing the warning sound from causing discomfort to the driver.

[0046] Furthermore, an ambient light (not shown) may be flashed to alert the driver to the departure of a vehicle ahead or exceeding the speed limit. The ambient light is a linear environmental light installed inside the vehicle. When flashing the ambient light, it is desirable to flash the notification image 44 in synchronization with the flashing of the ambient light. This makes it easier for the driver to notice the flashing light. In this case, for example, the control unit 13 acquires a synchronization signal for the flashing of the ambient light from the ECU and flashes the notification image 44 in synchronization with the flashing of the ambient light. In this case, it is also desirable for the control unit 13 (image processing unit 14) to flash the notification image 44 in a color similar to that of the ambient light.

[0047] When an ambient light is installed above the glove compartment of the passenger seat, the ambient light is often arranged in a line extending in the left-right direction. If the notification image 44, which is a long, narrow strip, also flashes in the left-right direction in synchronization with the flashing of the linear ambient light, the driver will be more likely to notice the flashing of the light. Therefore, when the ambient light is arranged in a line extending in the left-right direction, it is particularly effective to flash the notification image 44 in synchronization with the flashing of the ambient light.

[0048] It is desirable that the notification image 44 overlaps with a portion of another information image 42. For example, in the display screen 41 shown in Fig. 4B, the notification image 44 overlaps with a portion of a text image included in an indicator bar image 42D and an image indicating a set speed in a driving assistance image 42E. By overlapping the notification image 44 with a portion of another information image 42, it is possible to obtain the effect that the driver can easily notice the notification when checking the information image 42.

[0049] On the other hand, the notification image 44 does not have to overlap with other information images 42. By not overlapping the notification image 44 with other information images 42, the notification image 44 does not get in the way when the driver checks the other information images 42, and an effect can be obtained in which the annoyance felt by the driver can be reduced.

[0050] Incidentally, the driver's point of gaze when driving at high speed on a highway is located higher than the driver's point of gaze when driving at low speed in an urban area. As such, as the vehicle speed increases, the driver's point of gaze moves upward. Meanwhile, since the notification image 44 of this embodiment is displayed at the bottom edge of the display screen 41 (virtual image 40), if the driver's point of gaze moves upward when the vehicle is moving at high speed, the driver may have difficulty noticing the notification image 44. Therefore, the control unit 13 (image processing unit 14) may change the position of the upper edge of the notification image 44 according to the vehicle speed. For example, the control unit 13 increases the width (vertical dimension) of the notification image 44 when the vehicle speed increases, thereby moving the upper edge of the notification image 44 upward. This makes it easier for the driver to notice the notification even if the driver's point of gaze moves upward when the vehicle is moving at high speed. Furthermore, when the vehicle speed slows down, the control unit 13 narrows the width (vertical dimension) of the notification image 44, thereby moving the upper edge of the notification image 44 downward. This reduces the annoyance felt by the driver. Note that instead of changing the width of the notification image 44, the position of the upper edge of the notification image 44 may be changed by changing the vertical display position of the notification image 44.

[0051] As shown in FIG. 1 , the virtual image 40 is tilted relative to the vertical direction so that the lower edge is closer to the driver (the optical system 12 is configured to tilt the virtual image 40 in this manner). When the virtual image 40 is tilted in this manner, the distance (front-to-back distance) from the driver's point of gaze is longer at the lower edge of the virtual image 40 than at the upper edge. Therefore, the notification image 44 is displayed closer to the driver on the display screen 41. Because the driver's focus (point of gaze) is farther away than the virtual image 40, displaying the notification image 44 at the lower edge of the tilted virtual image 40 in this manner can increase the distance (front-to-back distance) between the driver's focus and the notification image 44, thereby reducing the annoyance felt by the driver when the notification image 44 is displayed. Note that the notification image 44 does not represent letters or marks but represents a predetermined color, so the driver can distinguish the color of the notification image 44 without focusing on the notification image 44. Therefore, it is permissible to increase the distance between the driver's focus (point of gaze) and the notification image 44 on the virtual image 40.

[0052] The arrangement of the virtual images 40 is not limited to that shown in Fig. 1. For example, the virtual images 40 may be arranged parallel to the vertical direction.

[0053] <Modification> FIG. 6 is an explanatory diagram of a modification of the display device 10. In FIG.

[0054] The display device 10 of the modified example forms two virtual images 40 (a first virtual image 40A and a second virtual image 40B). The image generation unit 11 (not shown in FIG. 6 ) has a first image generation unit that generates a first image and a second image generation unit that generates a second image. The optical system 12 (not shown in FIG. 6 ) has a first optical system that displays the first virtual image 40A using the first image and a second optical system that displays the second virtual image 40B using the second image. The first image generation unit and the second image generation unit may be configured as separate devices (e.g., two liquid crystal display devices) or may be configured as a single device by using a portion of a single image as the first image and another portion as the second image.

[0055] As shown in FIG. 6 , two virtual images 40 (a first virtual image 40A and a second virtual image 40B) are arranged at different positions in the vertical direction. In other words, two display screens 41 (a first display screen 41A and a second display screen 41B) are displayed at different positions in the vertical direction. Here, the upper virtual image 40 is the first virtual image 40A, and the lower virtual image 40 is the second virtual image 40B. In this modified example, the control unit 13 (image processing unit 14) displays a notification image 44 in a strip-shaped area at the bottom edge of the second virtual image 40B arranged at the bottom. By displaying the notification image 44 on the second virtual image 40B, the angle between the driver's line of sight and the line connecting the driver's eyes and the notification image 44 can be made larger compared to when the notification image 44 is displayed on the upper first virtual image 40A. This reduces the discomfort felt by the driver when the notification image 44 appears on the display screen 41.

[0056] As shown in FIG. 6 , the second virtual image 40B is positioned closer to the driver than the first virtual image 40A. In a modified example, the control unit 13 (image processing unit 14) displays the notification image 44 in a strip-shaped region at the bottom edge of the second virtual image 40B, which is positioned closer to the driver. Because the driver's focus is farther away than the first virtual image 40A and the second virtual image 40B, displaying the notification image 44 at the bottom edge of the second virtual image 40B increases the distance (forward / backward) between the driver's focus and the notification image 44, thereby reducing the annoyance felt by the driver when the notification image 44 is displayed. Since the notification image 44 displays a predetermined color, the driver can distinguish the color of the notification image 44 without focusing on the notification image 44. Therefore, increasing the distance between the driver's focus and the notification image 44 is permitted.

[0057] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments and includes various modifications. Furthermore, the above embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, some of the configurations of the above embodiments can be added to, deleted from, or replaced with other configurations.

[0058] REFERENCE SIGNS LIST 10 Display device, 11 Image generation unit, 12 Optical system, 13 Control unit, 14 Image processing unit, 15 Determination unit, 20 Transmission / reflection unit, 30 Detection unit, 40 Virtual image, 40A First virtual image, 40B Second virtual image, 41 Display screen, 42 Information image, 42A Vehicle speed image, 42B Shift position image, 42C Road sign image, 42D Indicator bar image, 42E Driving assistance image, 42F Navigation image, 44 Notification image, 100 Display system

Claims

1. A display device comprising: an image generating unit that generates an image; an optical system that projects the image as image light onto a transmissive reflecting unit to display a virtual image; and a control unit that displays a notification image for notification in a strip-like region at the bottom of the virtual image.

2. A display device according to claim 1, wherein the control unit causes the notification image to blink.

3. A display device according to claim 2, wherein the control unit blinks the notification image in synchronization with blinking of an ambient light.

4. A display device according to any one of claims 1 to 3, wherein the control unit displays the notification image in a different color depending on the type of notification.

5. A display device according to claim 4, wherein the control unit displays the notification image in blue when it detects drowsiness in the driver.

6. A display system comprising: an image generating unit that generates an image; a light-transmitting reflecting unit; an optical system that projects the image onto the transmissive reflecting unit as image light and displays a virtual image; and a control unit that displays a notification image for notification in a strip-like region at the lower edge of the virtual image.

Images