Projection device for vehicle

Abstract

An HUD (2) is provided with a concave mirror (28) for projecting a virtual image in front of a vehicle. The concave mirror (28) has a reflection surface (280), and the reflection surface (280) has two sides approximately parallel to each other and different in length. A right corner part (UR) of the reflection surface (280) has a chamfered shape.

Description

Vehicle Projection Device

[0001] The present disclosure relates to a vehicle projection device.

[0002] Patent Document 1 discloses a vehicle projection device that is installed in a vehicle and displays a predetermined image to the vehicle driver. The vehicle projection device includes an image generation unit that emits light to generate a predetermined image, a reflection unit that reflects the light emitted by the image generation unit so that the light is irradiated onto a windshield or a combiner, and a housing that accommodates the image generation unit and the reflection unit. The reflection unit has a main body, a first shaft that protrudes outward from one end of the main body, and a second shaft that protrudes outward from the other end of the main body. The housing has at least a first storage portion that can accommodate an end of the first shaft. The end is exposed to the outside from the first storage portion.

[0003] International Publication No. 2021 / 193074

[0004] The vehicle projection device is mounted in a predetermined location inside the vehicle, but since the space available for accommodating the vehicle projection device is limited, the vehicle projection device must be mounted in a way that does not interfere with other vehicle components (such as the windshield or dashboard).

[0005] The present disclosure provides a vehicle projection device that can easily avoid interference with other components of the vehicle.

[0006] A vehicle projection device according to one aspect of the present disclosure is a vehicle projection device equipped with a reflector for projecting a virtual image ahead of the vehicle, the reflector having a reflecting surface, and the reflecting surface having two sides that are substantially parallel to each other and have different lengths.

[0007] A vehicle projection device according to one aspect of the present disclosure is a vehicle projection device including a reflector for projecting a virtual image ahead of the vehicle, the reflector having a reflecting surface, the reflecting surface being substantially triangular in shape.

[0008] According to the present disclosure, a vehicle projection device that can easily avoid interference with other components of the vehicle is provided.

[0009] FIG. 1 is a schematic diagram of a HUD according to this embodiment, viewed from the side of a vehicle. FIG. 2 is a front view of a concave mirror, viewed from direction II in FIG. 1. FIG. 3 is a schematic diagram illustrating interference between the concave mirror and the windshield and dashboard of the vehicle. FIG. 4 is a schematic diagram illustrating interference between the concave mirror and the windshield and dashboard of the vehicle, viewed from above. FIG. 5 is a front view of a concave mirror according to Modification 1. FIG. 6 is a front view of a concave mirror according to Modification 2. FIG. 7 is a front view of a concave mirror according to Modification 3.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. For the sake of convenience, descriptions of components having the same reference numerals as those already described in the description of the embodiments will be omitted. Furthermore, for the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0011] Furthermore, in the description of this embodiment, for convenience of explanation, the terms "left-right direction," "up-down direction," and "front-rear direction" may be referred to as appropriate. These directions are relative directions set for the head-up display (HUD) 2 shown in FIG. 1 . Here, the "left-right direction" refers to a direction including a "left direction L" and a "right direction R." The "up-down direction" refers to a direction including an "upward direction U" and a "downward direction D." The "front-rear direction" refers to a direction including a "forward direction F" and a "rearward direction B." The front-rear direction in the HUD 2 and the front-rear direction in the vehicle 1 coincide with each other. Here, the traveling direction of the vehicle 1 is defined as the forward direction. Although not shown in FIG. 1 , the left-right direction refers to a direction perpendicular to the up-down direction and the front-rear direction. The left-right direction also corresponds to the width direction of the vehicle 1.

[0012] The HUD 2 also includes a concave mirror 28, as will be described later. The concave mirror 28 is tilted relative to the vehicle 1 so that the upper end of the concave mirror 28 faces forward in the direction F and the lower end of the concave mirror 28 faces backward in the direction B. In this embodiment, the upward direction of the concave mirror 28 is indicated by "u" and the downward direction of the concave mirror 28 is indicated by "d". The leftward direction of the concave mirror 28 is indicated by "l" and the rightward direction of the concave mirror 28 is indicated by "r". Although not shown in FIG. 1 , the left-right direction of the concave mirror 28 is a direction perpendicular to the up-down direction of the concave mirror 28.

[0013] First Embodiment Fig. 1 is a schematic diagram of a HUD 2 provided in a vehicle 1, viewed from the side of the vehicle 1. The HUD 2 is configured to project a virtual image onto a windshield WS so as to be superimposed on a scene ahead of the vehicle. At least a portion of the HUD 2 is located inside the vehicle 1. Specifically, the HUD 2 is installed in a dashboard DB of the vehicle 1. The HUD 2 is an example of a vehicle projection device.

[0014] As shown in Fig. 1, the HUD 2 includes an HUD main body 20. The HUD main body 20 has a housing 22 and an exit window 23. The exit window 23 is a transparent plate that transmits visible light. Inside the housing 22, the HUD main body 20 has a picture generation unit (PGU) 24, a HUD control unit 25, a plane mirror 26, and a concave mirror 28. The housing 22 has a shape corresponding to a reflective surface 280 of the concave mirror 28, which will be described later.

[0015] The image generation unit 24 is configured to emit light that generates a virtual image. The image generation unit 24 includes a light source, optical components, and a display device. The light source is, for example, a laser light source or an LED light source. The optical components include a prism, a lens, a diffuser, a magnifying glass, etc. The display device is, for example, a liquid crystal display, a DMD (Digital Mirror Device), or an LCOS (Liquid Crystal On Silicon).

[0016] An image forming surface made up of a large number of pixels is formed on the display device of the image generating unit 24. The image forming surface has a rectangular display area. The image generating unit 24 is configured to form a virtual image using a portion of the image forming surface.

[0017] The concave mirror 28 is disposed on the optical path of the light emitted from the image generator 24 and reflected by the plane mirror 26. Specifically, the concave mirror 28 is disposed in front of the image generator 24 and the plane mirror 26 within the HUD main body 20. The concave mirror 28 is configured to reflect the light emitted by the image generator 24 toward the windshield WS (e.g., the front window of the vehicle 1) through the exit window 23. The concave mirror 28 has a concavely curved reflective surface 280, and reflects the image of the light emitted from the image generator 24 and formed thereon at a predetermined magnification. In this way, the concave mirror 28 is used to project a virtual image ahead of the vehicle. The concave mirror 28 is an example of a reflecting mirror.

[0018] The HUD main body 20 does not necessarily have to have the plane mirror 26. In this case, the light emitted from the image generation unit 24 is incident on the concave mirror 28 without being reflected by the plane mirror 26.

[0019] Light emitted from the exit window 23 of the HUD main body 20 is irradiated onto the windshield WS. A portion of the light irradiated from the HUD main body 20 onto the windshield WS is reflected toward the driver's viewpoint E. As a result, the driver perceives the light (predetermined image) emitted from the HUD main body 20 as a virtual image formed at a predetermined distance in front of the windshield WS. In this way, the virtual image displayed by the HUD 2 is superimposed on the real space in front of the vehicle 1 through the windshield WS, allowing the driver to visually perceive the virtual image object I as floating above the road outside the vehicle.

[0020] The HUD control unit 25 is configured to control the image generation unit 24. The HUD control unit 25 is configured with a processor such as a CPU (Central Processing Unit), a memory, etc. When the processor executes a computer program read from the memory, the image generation unit 24 operates.

[0021] Next, the concave mirror 28 will be described in detail. FIG. 2 is a front view of the concave mirror 28 as viewed from direction II in FIG. 1. As shown in FIG. 2, the concave mirror 28 has a reflective surface 280. The reflective surface 280 has a first reflective region 281 and a second reflective region 282. The first reflective region 281 and the second reflective region 282 are regions that reflect light emitted from the image generation unit 24. The first reflective region 281 and the second reflective region 282 are each rectangular. The longitudinal direction of the first reflective region 281 and the longitudinal direction of the second reflective region 282 are approximately parallel to each other. In the illustrated example, the first reflective region 281 and the second reflective region 282 extend in the left-right direction.

[0022] In this example, the reflecting surface 280 has a hexagonal shape extending in the left-right direction as shown in Fig. 2. The reflecting surface 280 has an upper side 283, a lower side 284, a left side 285, a right side 286, a left oblique side 287, and a right oblique side 288.

[0023] The upper side 283 and the lower side 284 are substantially parallel to each other. The upper side 283 and the lower side 284 extend in the left-right direction. Furthermore, the length of the upper side 283 and the length of the lower side 284 are different from each other. In this embodiment, the length of the upper side 283 is shorter than the length of the lower side 284. The lower side 284 is substantially parallel to the longitudinal direction of the first reflective area 281 and the longitudinal direction of the second reflective area 282.

[0024] The left side 285 and the right side 286 are connected at their lower ends to the bottom side 284. The left side 285 and the right side 286 are substantially parallel to each other. In this embodiment, the left side 285 and the right side 286 are connected to the bottom side 284 substantially perpendicularly. Furthermore, the length of the left side 285 is the same as the length of the right side 286.

[0025] The corner formed by the imaginary extension line of the top side 283 and the imaginary extension line of the left side 285 is referred to as the left corner UL. The left corner UL is located at the upper left end of the reflecting surface 280. As shown in FIG. 2 , the left corner UL of the reflecting surface 280 has a chamfered shape, and the side formed by the chamfer is the left oblique side 287. The left oblique side 287 is connected to the top side 283 and the left side 285.

[0026] The corner formed by the imaginary extension of the top side 283 and the imaginary extension of the right side 286 is referred to as the right corner UR. The right corner UR is located at the upper right end of the reflecting surface 280. As shown in FIG. 2 , the right corner UR of the reflecting surface 280 has a chamfered shape, and the side formed by the chamfer is the right oblique side 288. The right oblique side 288 is connected to the top side 283 and the right side 286.

[0027] In this embodiment, the "chamfered shape" refers to a shape in which corners are cut off at an angle. In this embodiment, the angle at which each corner is cut off at an angle to one side is not limited to 45 degrees. The angle at which the corners are cut off may be smaller than 45 degrees. For example, the angle formed by the top side 283 and the right oblique side 288 may be larger than 135 degrees. Furthermore, the "chamfered shape" does not only refer to angular shapes, but also includes arc-shaped shapes, so-called R-chamfered shapes.

[0028] Thus, the reflective surface 280 has chamfered portions at the upper left end and the upper right end in the direction in which the parallel upper and lower edges 283 and 284 extend (the left-right direction in FIG. 2 ). In this embodiment, the chamfered portions at each end have the same shape. The length of the left oblique side 287 is the same as the length of the right oblique side 288. In other words, the reflective surface 280 of this embodiment has an axisymmetric shape.

[0029] Next, interference between the concave mirror 28 and the windshield WS and dashboard DB of the vehicle 1 will be described with reference to Figures 3 and 4. As described above, the image generation unit 24 of the HUD 2 has a rectangular display area. To reflect light from this rectangular display area, the concave mirror 28 has a rectangular first reflection area 281 and a rectangular second reflection area 282. In other words, the concave mirror 28 as a whole extends long and parallel to the bottom side 284.

[0030] The HUD 2 is installed on the dashboard DB and emits light onto the windshield WS. In order to project a virtual image onto the driver, the HUD 2 is disposed in a position close to the driver's seat in the left-right direction of the vehicle 1.

[0031] However, the left and right ends of the windshield WS are often curved toward the rear of the vehicle, so if the HUD 2 is to be placed on the dashboard DB near the driver's seat, the corners of the rectangular concave mirror 28 are likely to interfere with the curved windshield WS.

[0032] For example, if the driver's seat is located on the right side of the vehicle 1, the HUD 2 is also located on the right side of the dashboard DB. Meanwhile, the right end of the windshield WS curves toward the rear of the vehicle. In this case, the right corner of the concave mirror 28 of the HUD 2 is likely to interfere with the curved windshield WS.

[0033] Furthermore, the windshield WS is inclined so that the distance between the windshield WS and the dashboard DB becomes shorter from the center toward the right end in the left-right direction.

[0034] If the HUD 2 is installed so that light is emitted vertically upward, the distance between the HUD 2 and the windshield WS will be different at the left and right ends of the virtual image, which may cause distortion of the virtual image.

[0035] Fig. 3 is a schematic diagram illustrating interference between the concave mirror 28 and the windshield WS and dashboard DB of the vehicle 1. Fig. 3 illustrates a case where the steering wheel H of the driver's seat is provided on the right side of the vehicle 1. Fig. 3 is a diagram of a vertical cross section in front of the steering wheel H as seen from the driver's perspective, with the cross section of the windshield WS and the cross section of the top surface of the dashboard DB indicated by solid lines. Fig. 3 also depicts the steering wheel H with a dashed line to make it easier to understand the position where the HUD 2 is disposed.

[0036] As shown in Figure 3, the HUD 2 is positioned below the top surface of the dashboard DB. To reduce distortion of the virtual image, it is conceivable to tilt the HUD 2 to match the inclination of the windshield WS. However, the housing 22 of the HUD 2 is generally shaped like a rectangular parallelepiped, which could result in a portion of the housing 22 (the left corner UL in the illustrated example) protruding from the top surface of the dashboard DB. Positioning a rectangular parallelepiped HUD like this imposes design constraints.

[0037] However, according to this embodiment, the reflective surface 280 of the concave mirror 28 has an upper side 283 and a lower side 284 that are parallel to each other and have different lengths. More specifically, the reflective surface 280 has a first reflective area 281 and a second reflective area 282 that is larger than the first reflective area 281. The longitudinal direction of the first reflective area 281 and the longitudinal direction of the second reflective area 282 are approximately parallel to the upper side 283 and the lower side 284, respectively. This makes it easy to accommodate a rectangular display area.

[0038] Furthermore, because the upper edge 283 is shorter than the lower edge 284, at least one of the upper right and upper left edges of the reflective surface 280 has a missing corner. By placing the HUD 2 in a position as shown in Figure 3 in which this missing corner (the left corner UL in the illustrated example) is raised upward, even if the HUD 2 is placed in a tilted position to reduce distortion of the virtual image, a portion of the housing 22 is unlikely to protrude from the top surface of the dashboard DB.

[0039] Fig. 4 is a schematic diagram illustrating interference between the concave mirror 28 and the windshield WS and dashboard DB of the vehicle 1, as viewed from above. Fig. 4 also illustrates a case where the steering wheel H of the driver's seat is provided on the right side of the vehicle 1. Fig. 4 is a diagram showing the top surface of the dashboard DB as viewed from above the vehicle 1.

[0040] As shown in Figure 4, the windshield WS curves rearward from the center toward the right end. Therefore, the front-to-rear width of the top surface of the dashboard DB often narrows toward the right end. Because the HUD 2 is embedded in the top surface of the dashboard DB, if the steering wheel H is located on the right side of the vehicle 1, the right corner UR of the HUD 2 must be positioned to fit within the top surface of the dashboard DB in a top view. According to this embodiment, the right corner UR of the reflective surface 280 is missing, making it easy to position the HUD 2 to fit within the top surface of the dashboard DB in a top view.

[0041] Furthermore, of the two parallel sides of the reflective surface 280, the upper side 283 is shorter than the lower side 284. In this concave mirror 28, the corners (left corner UL and right corner UR) where the upper side 283 of the reflective surface 280 is located protrude less than the corners of a reflective surface having two parallel sides of equal length. By positioning this small-protruding part in a position that would normally interfere with the dashboard DB, the concave mirror 28 is less likely to interfere with the dashboard DB while suppressing distortion of the virtual image.

[0042] Furthermore, in the illustrated example, each corner (left corner UL and right corner UR) of the reflecting surface 280 is chamfered, so that the area of ​​the reflecting surface 280 where the shorter side (upper side 283) is located is less likely to interfere with the windshield WS than the area where the longer side (lower side 284) is located.

[0043] In this embodiment, the reflecting surface 280 has chamfered portions at each of the left corner UL and the right corner UR in the direction in which the parallel upper edge 283 and lower edge 284 extend. Because the reflecting surface 280 has two chamfered portions, the concave mirror 28 is less likely to interfere with the windshield WS and the dashboard DB while suppressing distortion of the virtual image.

[0044] The HUD 2 is disposed on the dashboard DB at a position close to the driver's seat. The driver's seat may be disposed on the right or left side of the vehicle 1. When the driver's seat is disposed on the right side of the vehicle 1, the HUD 2 is disposed on the right side of the vehicle 1, and the right corner UR of the concave mirror 28 is likely to interfere with the windshield WS, while the left corner UL is likely to interfere with the dashboard DB. On the other hand, when the driver's seat is disposed on the left side of the vehicle 1, the HUD 2 is disposed on the left side of the vehicle 1, and the left corner UL of the concave mirror 28 is likely to interfere with the windshield WS, while the right corner UR is likely to interfere with the dashboard DB. According to this embodiment, the reflective surface 280 has an axisymmetric shape. By making each end (the left corner UL and the right corner UR) a common shape that is unlikely to interfere with both the windshield WS and the dashboard DB, the HUD 2 can be easily disposed on the dashboard DB regardless of whether the HUD 2 is disposed on the left or right side of the vehicle 1.

[0045] The HUD 2 has a housing 22 shaped to correspond to the reflective surface of the concave mirror 28. Therefore, the housing 22 is less likely to interfere with the windshield WS and the dashboard DB.

[0046] (Modification 1) In the first embodiment, the chamfered portions have the same shape, but the chamfered portions may have different shapes. Fig. 5 is a front view of a concave mirror 28A according to Modification 1. In the configuration shown in Fig. 5, the same components as those shown in Fig. 2 are designated by the same reference numerals, and their description will be omitted.

[0047] As shown in Figure 5, the concave mirror 28A has a reflective surface 280A. Both the left corner UL and the right corner UR of the reflective surface 280A are chamfered. In this modified example, the chamfered portions have different shapes. The length of the left oblique side 287A is shorter than the length of the right oblique side 288A. In other words, the reflective surface 280A of this modified example has an asymmetrical shape.

[0048] When the driver's seat is located on the right side of the vehicle 1, the right corner UR of the concave mirror 28A is likely to interfere with the windshield WS, and the left corner UL is likely to interfere with the dashboard DB. According to this modification, the chamfered portions have different shapes. When different components are likely to interfere at each corner, the shapes of each end can be made different to match those components. For example, the right corner UR may be chamfered to minimize interference with the windshield WS, and the left corner UL may be chamfered to minimize interference with the dashboard DB. When the driver's seat is located on the left side of the vehicle 1, the left corner UL may be chamfered to minimize interference with the windshield WS, and the right corner UR may be chamfered to minimize interference with the dashboard DB.

[0049] (Modification 2) Fig. 6 is a front view of a concave mirror 28B according to Modification 2. In the configuration shown in Fig. 6, the same components as those shown in Fig. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0050] As shown in FIG. 6 , the concave mirror 28B has a trapezoidal reflecting surface 280B. The reflecting surface 280B has an upper side 283, a lower side 284, a left side 285, and a right oblique side 288B. In other words, the reflecting surface 280B does not have a left oblique side or a right side. The corner formed by the upper side 283 and the left side 285 is referred to as the left corner ULB. The left corner ULB of the reflecting surface 280B is not chamfered. The left side 285 is connected to the upper side 283 and the lower side 284 at a substantially right angle.

[0051] In this modified example, the corner formed by an imaginary extension line of the upper side 283 and an imaginary extension line extending approximately perpendicularly upward from the right end of the lower side 284 is referred to as the right corner URB. The right corner URB is located at the right end of the reflecting surface 280B. As shown in FIG. 6 , the right corner URB of the reflecting surface 280B has a chamfered shape, and the side formed by the chamfer is the right oblique side 288B. The right oblique side 288B is connected to the upper side 283 and the lower side 284. The reflecting surface of this modified example has an asymmetrical shape.

[0052] As described above, the reflecting surface 280B of this modified example has a trapezoidal shape. At least the right corner URB is chamfered, which has the effect of preventing interference with the windshield WS or dashboard DB.

[0053] The corners of the first reflective area 281B and the second reflective area 282B may be chamfered to match the chamfered shape of the reflective surface 280B (FIG. 6). In this case, it is possible to ensure as large a reflective area as possible while avoiding interference with the windshield WS or the dashboard DB. The chamfered shape of the first reflective area 281B may be line-symmetric or asymmetric. The chamfered shape of the second reflective area 282B may be line-symmetric or asymmetric.

[0054] (Modification 3) Fig. 7 is a front view of a concave mirror 28C according to Modification 3. In the configuration shown in Fig. 7, the same components as those shown in Fig. 2 are denoted by the same reference numerals, and the description thereof will be omitted.

[0055] As shown in Figure 7, the concave mirror 28C has a substantially triangular reflective surface 280C. The reflective surface 280C has a bottom side 284, a left oblique side 287C, and a right oblique side 288C. The left oblique side 287C and the right oblique side 288C are in contact with each other above the reflective surface 280C. In other words, the reflective surface 280C does not have a top side, left side, or right side. Such a substantially triangular reflective surface 280C also exhibits the same effect as above, that is, it is less likely to interfere with the windshield WS or the dashboard DB.

[0056] The corners of the first reflective area 281C and the second reflective area 282C may be chamfered to match the triangular shape of the reflective surface 280C (FIG. 7). In this case, it is possible to ensure as large a reflective area as possible while avoiding interference with the windshield WS or the dashboard DB. The chamfered shape of the first reflective area 281C may be line-symmetric or asymmetric. The chamfered shape of the second reflective area 282C may be line-symmetric or asymmetric.

[0057] Although the embodiments of the present disclosure have been described above, it goes without saying that the technical scope of the present disclosure should not be interpreted as being limited by the description of the present embodiments. The present embodiments are merely examples, and it will be understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present disclosure should be determined based on the scope of the invention described in the claims and its equivalents.

[0058] The configurations described in the following items also constitute part of the present disclosure. Item 1: A vehicle projection device including a reflecting mirror for projecting a virtual image ahead of a vehicle, wherein the reflecting mirror has a reflecting surface, and the reflecting surface has two sides that are substantially parallel to each other and have different lengths. Item 2: The vehicle projection device according to item 1, wherein corners of the reflecting surface are chamfered. Item 3: The vehicle projection device according to item 1 or 2, wherein the reflecting surface has a chamfered portion at each end in the direction in which the parallel sides extend. Item 4: The vehicle projection device according to item 3, wherein the chamfered portions provided at each end have mutually different shapes. Item 5: The vehicle projection device according to any one of items 1 to 4, wherein the reflecting surface is trapezoidal. Item 6: The vehicle projection device according to any one of items 1 to 3 and 5, wherein the reflecting surface has an axisymmetric shape. Item 7: The vehicle projection device according to any one of items 1 to 6, further comprising a housing having a shape corresponding to the reflective surface of the reflector.

[0059] This application claims priority based on Japanese Application No. 2023-160077, filed on September 25, 2023, and incorporates by reference all of the contents of the aforementioned Japanese application.

Claims

1. A vehicle projection device equipped with a reflector for projecting a virtual image in front of the vehicle, the reflector having a reflective surface, the reflective surface having two sides that are approximately parallel to each other and have different lengths.

2. The vehicle projection device according to claim 1, wherein the corners of the reflecting surface are chamfered.

3. The vehicle projection device according to claim 1, wherein the reflection surface has a chamfered portion at each end in the direction in which the parallel sides extend.

4. The vehicle projection device according to claim 3, wherein the chamfered portions at each of the ends have different shapes.

5. The vehicle projection device according to claim 1, wherein the reflecting surface is trapezoidal in shape.

6. The vehicle projection device according to claim 1, wherein the reflecting surface has an axisymmetric shape.

7. The vehicle projection device according to claim 1, further comprising a housing having a shape corresponding to the reflecting surface of the reflector.

8. A vehicle projection device comprising a reflector for projecting a virtual image in front of the vehicle, the reflector having a reflecting surface, the reflecting surface being substantially triangular in shape.

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