Head-up display

Abstract

To provide a head-up display that makes an image suitably visible in switching between different display positions.SOLUTION: A head-up display comprises: a display unit which generates display light related to an image to be displayed in a display region D1 of a virtual image, and generates display light related to an image to be displayed in a display region D2 of a real image; a switching unit which switches the light to be projected on a windshield 10, between the display lights, and switches an image to be visible to a viewer 3, between a virtual image and a real image; and a display region controlling unit which moves the display region D1 of one image out of the virtual image and the real image being visible inside a visible range A1, to the outside A2 of the visible range, in switching between the display lights, and which, after the switching, moves the display region D2 of the other image out of the virtual image and the real image, from the outside A2 of the visible range to the inside A1 of the visible range.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to head-up displays. [Background technology]

[0002] 2. Description of the Related Art Head-up displays are known in the art that reflect display light off a reflective member such as a windshield of a vehicle, allowing an image to be viewed both inside and outside the vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 2] Japanese Patent Application Publication No. 2017-056844 Summary of the Invention [Problem to be solved by the invention]

[0004] A head-up display switches the display position of an image between the inside and outside of a vehicle by switching the focal length. This allows the head-up display to create a visual effect that suits the content of the image. When the display position switches, the viewer momentarily adjusts the focus to view the image. However, such focus adjustments can be uncomfortable for the viewer, and some kind of solution has been sought.

[0005] The present disclosure has been made in consideration of the above circumstances, and aims to provide a head-up display that allows an image to be viewed favorably when switching between different display positions. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the head-up display of the present disclosure is a head-up display that projects and reflects first display light onto a reflecting member having an inner surface and an outer surface, and allows a viewer to view an image of a virtual image related to the first display light displayed in a display area of ​​a virtual image on the outer surface side within a visible range of the virtual image, and projects and reflects second display light onto the reflecting member, and allows a viewer to view an image of a real image related to the second display light displayed in a display area of ​​a real image on the inner surface side within a visible range of the real image, The display device includes a display unit that generates a first display light and generates a second display light related to an image displayed within a display area of ​​the real image; a switching unit that switches the light projected onto the reflective member between the first display light and the second display light, and switches the image that is viewed by the viewer between a virtual image and a real image; and a display area control unit that, when switching between the first display light and the second display light, moves the display area of ​​one of the virtual image and real image that is viewed within the visible range to outside the visible range, and after switching, moves the display area of ​​the other of the virtual image and real image from outside the visible range to within the visible range. [Effects of the Invention]

[0007] In the head-up display of the present disclosure, the image can be visually recognized favorably when switching between different display positions. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of a system configuration of an embodiment of a HUD according to the present disclosure, illustrating the display of a virtual image. [Figure 2] FIG. 1 is a diagram showing an example of a system configuration of an embodiment of a HUD according to the present disclosure, and is an explanatory diagram showing how a real image is displayed. [Figure 3] 10 is a flowchart illustrating a display switching process executed by the HUD. [Figure 4] FIG. 10 is an explanatory diagram showing how the display areas of the virtual image and the real image move. [Figure 5] FIG. 10 is an explanatory diagram showing a state in which the display areas of the virtual image and the real image move according to a first modified example. [Figure 6] FIG. 10 is an explanatory diagram showing a state in which a display area of ​​a virtual image moves according to a second modified example. [Figure 7] FIG. 10 is an explanatory diagram showing a state in which a display area of ​​a real image moves according to a third modified example. [Figure 8] FIG. 10 is an explanatory diagram showing a state in which a display area of ​​a virtual image moves as a fourth modified example. [Figure 9] FIG. 10 is a diagram showing the system configuration of a modified HUD. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of a head-up display (hereinafter referred to as a "HUD") according to the present disclosure will be described with reference to the accompanying drawings. The HUD according to the present disclosure can be applied to HUDs mounted on vehicles such as automobiles, agricultural machinery, and construction machinery.

[0010] FIG. 1 is a diagram showing an example of the system configuration of an embodiment of a HUD according to the present disclosure, and is an explanatory diagram showing the display of a virtual image V. FIG. 2 is a diagram showing an example of the system configuration of an embodiment of the HUD of the present disclosure, and is an explanatory diagram when a real image R is displayed.

[0011] In the following description, "front," "rear," "upper," and "lower" follow the definitions of "Fr.", "Re.", "To.", "Bo.", "R," and "L" in Figures 1, 2, and 4 to 9.

[0012] The HUD 1 is mounted, for example, in an instrument panel in front of the front seats of a vehicle. The HUD 1 projects and reflects display lights L1 and L2 from the rear and below onto a windshield 10 (a reflective member) of the vehicle. The HUD 1 displays an aerial image consisting of a virtual image V associated with the display light L1 (first display light) on the outer surface 10b (front) of the windshield 10, i.e., outside the vehicle, in front of the vehicle, for a viewer 3 (e.g., the driver) who is a passenger in the vehicle to view. The HUD 1 also displays an aerial image consisting of a real image R associated with the display light L2 (second display light) on the inner surface 10a (rear) of the windshield 10, i.e., inside the vehicle, for a viewer 3 to view. The HUD 1 forms an eyebox 4, which is an area where the viewer 3's viewpoint is expected to be located, and which is an area where the virtual image V and real image R are visible. The viewer 3 can view the virtual image V and real image R displayed by the HUD 1 by positioning their viewpoint within the eyebox 4. On the other hand, when the viewer 3 moves his / her viewpoint away from the eyebox 4, at least a part of the virtual image V and the real image R becomes unrecognizable (difficult to recognize).

[0013] The display light L1 relates to images that are displayed, for example, during manual driving of the vehicle, to provide information necessary for driving, such as driving speed, engine RPM, blind spot indicator, warning information such as speed limit exceeding warning, route guidance information, etc. The display light L2 relates to characters (assistants, agents) that provide various information to support the driver as the viewer 3, and images (contents) that provide entertainment to the viewer 3, that are displayed, for example, during automatic driving of the vehicle or when the vehicle is stopped.

[0014] The HUD 1 includes a windshield 10 and a display device 20 .

[0015] The windshield 10 has an inner surface 10a and an outer surface 10b, and reflects the display lights L1 and L2 toward the viewer 3.

[0016] The display device 20 includes an image generating unit 21, a first mirror 31, a second mirror 32, a third mirror 33 (a reflecting mirror), and a housing 35.

[0017] The image generation unit 21 is a display unit that generates display light L1 related to the image of the virtual image V displayed in the display area of ​​the virtual image V, and generates display light L2 related to the image of the real image R displayed in the display area of ​​the real image R. The image generation unit 21 includes a light source 22, a display element 23, a switching element 24, and a control unit 25.

[0018] The light source 22 is, for example, a light-emitting diode mounted on a wiring board and emitting light in the visible wavelength range. The light emitted from the light source 22 is homogenized by passing through optical members (not shown), such as a condenser lens, a lenticular lens, or a diffuser. The display element 23 is, for example, a TFT (Thin Film Transistor) liquid crystal display element. The switching element 24 extracts S-polarized light or P-polarized light as a specific polarization from the display light emitted from the display element 23. Specifically, the switching element 24 switches the extracted display light between an S-polarized component and a P-polarized component, and passes only one of the polarization components. The switching element 24 switches the polarization component to be passed by electrical control based on whether or not a current is applied. Here, the S-polarized component of the display light emitted from the display element 23 is designated as display light L1, and the P-polarized component is designated as display light L2.

[0019] The control unit 25 controls the lighting of the light source 22. The control unit 25 also controls the display element 23 to generate a required image (or display light related to the image). Furthermore, the control unit 25 controls the switching element 24 so that the switching element 24 switches the display light that it emits.

[0020] In this embodiment, the control unit 25 functions as a switching unit that switches the light projected onto the windshield 10 between display light L1 and display light L2, and switches the image to be viewed by the viewer 3 between a virtual image V and a real image R. The control unit 25 also functions as a display area control unit that moves the display area of ​​one of the virtual image V and real image R viewed within the visible range to outside the visible range, and after the image is switched, moves the display area of ​​the other of the virtual image V and real image R from outside the visible range to within the visible range. The light source 22, the display element 23, and the switching element 24 also function as display units that generate images formed with two different polarized light and viewed by the viewer 3, and emit the polarized light related to the images.

[0021] The first mirror 31, the second mirror 32, and the third mirror 33 are flat or curved mirrors. The first mirror 31 reflects the display light L1, which is an S-polarized component, and transmits the display light L2, which is a P-polarized component. The second mirror 32 reflects the display light L2 that passes through the first mirror 31. As shown in FIG. 2, since the first mirror 31 is a mirror that transmits the display light L2, the display light L2 reflected by the second mirror 32 naturally passes from the back side to the front side of the first mirror 31. Therefore, the display light L2 reflected by the second mirror 32 passes through the first mirror 31 again and is guided to the third mirror 33. This allows the second mirror 32 to be disposed close to the first mirror 31, thereby preventing the housing 35 from becoming large.

[0022] The display lights L1 and L2 reflected by the first mirror 31 and the second mirror 32 are guided to the third mirror 33. The third mirror 33 reflects the display lights L1 and L2 toward the windshield 10. The third mirror 33 also has a drive unit (not shown) that is driven based on the control of the control unit 25, and rotates around a rotation axis 34. This allows the third mirror 33 to change the reflection direction of the incident light.

[0023] The housing 35 supports and houses the image generating unit 21, the first mirror 31, the second mirror 32, and the third mirror 33. The housing 35 has an opening at the top, through which the display lights L1 and L2 reflected by the third mirror 33 are emitted to the outside of the housing 35. The opening is covered with a cover 36 to prevent dust and other particles from entering the inside of the housing 35.

[0024] Next, the operation of the HUD 1 in this embodiment when displaying an aerial image will be described.

[0025] When the HUD 1 displays an aerial image consisting of a virtual image V, the image generation unit 21 emits display light L1 associated with the virtual image V, as shown in FIG. 1 . That is, under the control of the control unit 25, the image generation unit 21 causes the display element 23 to generate an image using light emitted from the light source 22 to display the virtual image V, and further causes the switching element 24 to emit display light L1 consisting of the S-polarized component of the display light. The display light L1 is reflected sequentially by the first mirror 31 and the third mirror 33, and is emitted from the opening. The emitted display light L1 is reflected by the windshield 10 toward the viewer 3, and is viewed by the viewer 3.

[0026] Here, when the first mirror 31, the third mirror 33, and the windshield 10 are considered to be a single imaging optical system, by arranging the image generating unit 21 sufficiently close to the first mirror 31, the composite focus F1 of the imaging optical system is positioned in front of the light source 22. By setting the position of the composite focus F1 in this way, the HUD 1 causes the virtual image V to be visible on the outer surface 10b side of the windshield 10, i.e., in front of the vehicle.

[0027] On the other hand, when the HUD 1 displays an aerial image consisting of a real image R, the image generation unit 21 emits display light L2 corresponding to the real image R, as shown in Fig. 2. That is, in the image generation unit 21, under the control of the control unit 25, the display element 23 generates an image using light emitted from the light source 22 to display the real image R, and the switching element 24 further emits display light L2 consisting of the P-polarized component of the display light. The display light L2 passes through the first mirror 31, is reflected successively by the second mirror 32 and the third mirror 33, and is emitted from the opening. The emitted display light L2 is reflected by the windshield 10 toward the viewer 3 and is viewed by the viewer 3.

[0028] Here, when the second mirror 32, the third mirror 33, and the windshield 10 are considered to be a single imaging optical system, by arranging the image generating unit 21 at a position sufficiently far from the second mirror 32, the composite focus F2 of the imaging optical system is positioned after the light source 22. By setting the position of the composite focus F2 in this way, the HUD 1 allows the real image R to be viewed on the inner surface 10a side of the windshield 10, i.e., inside the vehicle.

[0029] In this way, the HUD 1 (display device 20) projects and reflects display light L1 made of S-polarized light onto the windshield 10 from the inner surface 10a of the windshield 10, causing a virtual image V made of S-polarized light to be viewed on the outer surface 10b of the windshield 10. The HUD 1 also projects and reflects display light L2 made of P-polarized light onto the windshield 10 from the inner surface 10a of the windshield 10, causing a real image R to be viewed on the inner surface 10a of the windshield 10. The HUD 1 displays the virtual image V during manual driving and the real image R during automatic driving or when the vehicle is stopped, for example, based on control by a vehicle ECU that comprehensively controls the vehicle.

[0030] Here, the HUD 1 switches the display of the virtual image V and the real image R based on information obtained from the vehicle ECU or the like as described above, and allows the viewer 3 to view the image. That is, the HUD 1 switches the display position of the image, causing the viewer 3 to adjust the focal length and switch the viewpoint from the virtual image V to the real image R, or from the real image R to the virtual image V. Such a switch may give the viewer 3 a sense of discomfort, as if the display had suddenly switched without any warning. For this reason, it is preferable to perform display control such that the viewer 3 can accept the switch between the virtual image V and the real image R without feeling uncomfortable.

[0031] Therefore, the HUD 1 of this embodiment eliminates the discomfort described above by controlling the movement of the display areas of the virtual image V and the real image R when switching the light projected onto the windshield 10 between the display light L1 and the display light L2 and switching the image viewed by the viewer 3 between the virtual image V and the real image R. This will be explained in detail below.

[0032] FIG. 3 is a flowchart illustrating the display switching process executed by the HUD 1. FIG. 4 is an explanatory diagram showing how the display areas D1 and D2 of the virtual image V and the real image R move.

[0033] This process is initiated when a display switch occurs between the virtual image V and the real image R while the virtual image V or the real image R is being displayed. The display switch occurs, for example, when it is detected based on information from the vehicle ECU or the like that the vehicle has been switched between automatic driving and manual driving, or that the shift lever has been switched between P range and D range.

[0034] In step S1, the control unit 25 controls the drive unit to rotate the third mirror 33 in order to move the display area of ​​one of the images currently visible within the visible range outside the currently set visible range of the eye box 4.

[0035] In step S2, as the third mirror 33 rotates, the display area of ​​one of the images moves from within the visible range to outside the visible range. The control unit 25 moves the display area, for example, vertically. Specifically, as shown in FIG. 4, when the virtual image V is being displayed, the control unit 25 controls the drive unit of the third mirror 33 so that the display area D1 of the virtual image V, which is within the visible range A1, moves downward to outside the visible range A2. The viewer 3 perceives the virtual image V as gradually moving downward and disappearing toward the road surface. At this time, the virtual image V usually displays an image related to information necessary for driving when the viewer 3 is manually driving. Therefore, when the display area D1 is moved to outside the visible range A2, it is moved to a position other than upward so as not to obstruct the forward field of view of the viewer 3 as a driver.

[0036] In step S3, control unit 25 switches the light projected onto windshield 10 between display light L1 and display light L2. Control unit 25 may switch after the display area is completely outside the visible range A2, or may switch when part of the display area is within the visible range A1 but the image within the display area is outside the display area. Subsequently, or simultaneously, in step S4, control unit 25 controls the drive unit to rotate third mirror 33 in order to move the display area of ​​the other image displayed after the switch from outside the visible range A2 to within the visible range A1.

[0037] In step S5, as the third mirror 33 rotates, the display area of ​​the other image moves from the out-of-visibility range A2 into the visible range A1. For example, as shown in FIG. 4, the control unit 25 controls the drive unit of the third mirror 33 so that the display area D2 of the real image R outside the visible range A2 moves from below to above, thereby moving into the visible range A1. The viewer 3 perceives the real image R gradually moving upward from the road surface and emerging from the dashboard, replacing the virtual image V that has disappeared onto the road surface. In other words, the HUD 1 allows the viewer 3 to perceive the virtual image V and real image R as if they have moved backward across the road surface, allowing the viewer 3 to perceive the image switch without any sense of discomfort. Furthermore, the viewer 3 can focus on a real object, such as the dashboard, making it easier to adjust the focus. Therefore, the HUD 1 in this embodiment allows the viewer 3 to view the image favorably when switching between different display positions.

[0038] The control of moving the display areas of the virtual image V and the real image R is not limited to the example of FIG. 4, and may be performed, for example, as follows.

[0039] FIG. 5 is an explanatory diagram showing a state in which the display areas D1 and D2 of the virtual image V and the real image R move as a first modified example.

[0040] 4 in that after switching from the virtual image V to the real image R, the display area D2 of the real image R moves from above to below, moving from outside the visible range A2 to within the visible range A1 of the viewer 3. By switching in this manner, the HUD 1 can make a strong impression of the change from the virtual image V to the real image R, and can reliably recognize that, for example, driving has been switched from manual to automatic.

[0041] Fig. 6 is an explanatory diagram showing a state in which a display area D1 of a virtual image V moves as a second modified example. Fig. 7 is an explanatory diagram showing a state in which a display area D2 of a real image R moves as a third modified example.

[0042] In the second variant, when the display area D1 crosses the boundary B1 between the inside visible range A1 and the outside visible range A2, the HUD1 reduces the visibility of the image within the visible range A1 close to the boundary B1 compared to the visibility of the image (virtual image V) within the visible range A1 far from the boundary B1.

[0043] Specifically, as shown in Figure 6, when the virtual image V moves downward as the display area D1 moves and crosses the boundary B1, for example, when it approaches the boundary B1 from a position P1 that is a predetermined distance away from the boundary B1 in the direction of the visible range A1, the HUD1 displays the area of ​​the image closer to the boundary B1 than position P1 using a gradation to reduce visibility as it approaches the boundary B1.

[0044] In addition, in the third variant, when the display area D2 straddles the boundary B2 between the inside visible range A1 and the outside visible range A2, the HUD1 reduces the visibility of the image within the visible range A1 close to the boundary B2 compared to the visibility of the image (real image R) within the visible range A1 far from the boundary B2.

[0045] Specifically, as shown in FIG. 7, when the real image R moves upward as the display area D2 moves and crosses the boundary B2, for example, when the real image R approaches the boundary B2 from a position P2 that is a predetermined distance away from the boundary B2 in the direction of the visible range A1, the HUD1 displays the area of ​​the image closer to the boundary B2 than the position P2 using a gradation to reduce visibility as the area approaches the boundary B2.

[0046] The method of reducing visibility is not limited to gradation, and other methods such as gradually reducing the overall brightness may also be used. In the second and third modified examples, the HUD 1 reduces visibility when the virtual image V and real image R move across the boundaries B1 and B2, thereby reducing the sense of discomfort caused by the image suddenly disappearing outside the visible range A2.

[0047] FIG. 8 is an explanatory diagram showing a state in which the display area D1 of the virtual image V moves as a fourth modified example.

[0048] In the fourth modified example, the image generating unit 21 moves the image (virtual image V) displayed in the display region D1 in the same direction as the movement direction of the display region D1, in accordance with the movement of the display region D1.

[0049] Specifically, when the display region D1 moves from inside the visible range A1 to outside the visible range A2, the image generation unit 21 generates the display light L1 so that the virtual image V itself moves downward within the display region D1 as the display region D1 moves downward. Also, when the display region D1 moves from outside the visible range A2 to inside the visible range A1, the image generation unit 21 generates the display light L1 so that the virtual image V itself moves upward within the display region D1 as the display region D1 moves upward. The fourth modified example can be similarly applied to the movement of the display region D2 when switching from the real image R to the virtual image V.

[0050] This reduces the time it takes for the image to move to the outside of the visible range A2, and reduces the time it takes to switch between the virtual image V and the real image R.

[0051] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the claims. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the inventions described in the claims and their equivalents.

[0052] For example, although the example has been described in which the first polarized light is S-polarized and the second polarized light is P-polarized, the first polarized light may be P-polarized and the second polarized light may be S-polarized. Furthermore, the first polarized light and the second polarized light are not limited to S-polarized and P-polarized light, as long as the polarization angles of the first polarized light and the second polarized light are different. In this case, for example, it is preferable that the difference in polarization angle between the first polarized light and the second polarized light is 22.5 degrees or more. Furthermore, the present invention is not limited to a method of switching between the real image R and the virtual image V by changing the polarization.

[0053] 9, the HUD 1 may have an image generation unit 21a for the virtual image V and an image generation unit 21b for the real image R. In this case, the image generation unit 21a for the virtual image V is disposed, for example, on the rear side of the second mirror 32. The second mirror 32 is a mirror that transmits the display light L1 emitted from the image generation unit 21a for the virtual image V and reflects the display light L2 emitted from the image generation unit 21b for the real image R.

[0054] Furthermore, the eyebox 4 when the virtual image V is displayed and the eyebox 4 when the real image R is displayed are set at the same position, but they may be set at different positions. [Explanation of symbols]

[0055] 1 Head Up Display (HUD) 3. Viewer 4 Eye Box 10 Windshield 10a Inner surface 10b External surface 20 Display device 21, 21a, 21b Image generation unit 22 Light source 23 Display element 24 Switching element 25 Control Unit 31 First Mirror 32 Second Mirror 33 Third Mirror 34 Rotation axis 35 cabinet 36 Cover A1 Within visual range A2 Out of sight B1, B2 boundary D1, D2 display area F1, F2 composite focus L1, L2 display light P1, P2 position R real image V Virtual Image

Claims

1. A head-up display that projects and reflects first display light onto a reflecting member having an inner surface and an outer surface, allowing a viewer to view an image of the virtual image related to the first display light displayed within a display area of ​​a virtual image on the outer surface side within a visible range of the virtual image, and projects and reflects second display light onto the reflecting member, allowing a viewer to view an image of the real image related to the second display light displayed within a display area of ​​a real image on the inner surface side within a visible range of the real image, a display unit that generates the first display light related to the image displayed in the display area of ​​the virtual image and generates the second display light related to the image displayed in the display area of ​​the real image; a switching unit that switches the light projected onto the reflecting member between the first display light and the second display light, and switches the image that the viewer views between the virtual image and the real image; a display area control unit that, when switching between the first display light and the second display light, moves the display area of ​​one of the virtual image and the real image that is visible within the visible range to outside the visible range, and, after switching, moves the display area of ​​the other of the virtual image and the real image from outside the visible range to within the visible range.

2. The head-up display according to claim 1 , wherein the display area control unit moves the display area in a vertical direction.

3. 3. The head-up display according to claim 2, wherein the display area control unit moves the display area of ​​one of the images downward out of the visible range and moves the display area of ​​the other of the images upward into the visible range.

4. 2. The head-up display according to claim 1, wherein when the display area crosses a boundary between the visible range and outside the visible range, the display unit reduces the visibility of the image within the visible range that is closer to the boundary compared to the image within the visible range that is farther from the boundary.

5. The head-up display according to claim 1 , wherein the display unit moves the image displayed in the display area in the same direction as the movement of the display area as the display area moves.

6. a reflecting mirror that reflects the first display light and the second display light emitted from the display unit, The head-up display according to claim 1 , wherein the display area control unit moves the display area by controlling a reflection direction of the reflecting mirror.

Images