Head-up display

Abstract

The present invention provides a head-up display device that can be miniaturized. The head-up display device projects display light L onto a windshield so that a virtual image V can be visually recognized by a viewer whose viewpoint is within a visible region R. The head-up display device includes: a display unit that radiates display light L; a first mirror 11 having a reflecting surface 11a that reflects the display light L radiated from the display unit; and a second mirror 12 that reflects the display light L reflected by the first mirror 11 toward the windshield. The display light L intersects with intersections CP2 and CP3 in the height direction. A portion of the reflecting surface 11a of the first mirror 11 is contained within an imaginary circle C having a diameter D of a line segment connecting the intersections CP2 and CP3. The intersection CP2 is a point at which the display light L intersects with the viewpoint at the upper end of the visible region R in the height direction. The intersection CP3 is a point at which the display light L intersects with the viewpoint at the lower end of the visible region R in the height direction.

Description

Technical Field

[0001] The present invention relates to a head-up display device. Background Art

[0002] For example, the head-up display device described in Patent Document 1 includes: a display that emits display light; a first mirror that reflects the display light emitted by the display; and a second mirror that reflects the display light reflected by the first mirror. The first mirror causes the reflected display light to intersect vertically at an intersection point before reaching the second mirror.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2018 / 198821 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the structure described in Patent Document 1, various components such as the first mirror and the second mirror need to be arranged so as not to obstruct the optical path of display light, resulting in an increase in the size of the head-up display device.

[0008] The present invention has been made in view of the above-mentioned actual situation, and an object of the present invention is to provide a head-up display device that can be miniaturized.

[0009] Means for solving problems

[0010] To achieve the above-mentioned object, a head-up display device according to the present invention projects display light onto a projection target member so that a virtual image can be visually recognized by a viewer whose viewpoint is within a visible area. The head-up display device includes: a display unit that emits the display light; a first mirror having a reflective surface that reflects the display light emitted from the display unit; and a second mirror that reflects the display light reflected by the first mirror toward the projection target member, wherein the display light intersects at a first intersection point and a second intersection point in a specific direction, at least a portion of the reflective surface of the first mirror is contained within an imaginary circle having a line segment connecting the first intersection point and the second intersection point as its diameter, the first intersection point being a point at which the display light intersects with a viewpoint corresponding to a first end of the visible area in the specific direction, and the second intersection point being a point at which the display light intersects with a viewpoint corresponding to a second end of the visible area in the specific direction opposite to the first end.

[0011] Effects of the Invention

[0012] According to the present invention, a head-up display device can be miniaturized.

[0013] Brief description of the accompanying drawings

[0014] Figure 1 It is a schematic diagram of a vehicle according to one embodiment of the present invention.

[0015] Figure 2 It is a schematic diagram of a head-up display device according to one embodiment of the present invention.

[0016] Figure 3 Schematic diagram of a head-up display device according to one embodiment of the present invention when the viewpoint is located at the center of the visible area.

[0017] Figure 4 Schematic diagram of a head-up display device according to one embodiment of the present invention when the viewpoint is located at the upper end of the visible area.

[0018] Figure 5 Schematic diagram of a head-up display device according to one embodiment of the present invention when the viewpoint is located at the lower end of the visible area.

[0019] Figure 6 Schematic diagram showing the optical path of display light according to one embodiment of the present invention when viewed from the width direction.

[0020] Figure 7 Schematic diagram showing the optical path of display light when viewed from the width direction according to the comparative example.

[0021] Figure 8 It is a schematic diagram showing the optical path of display light viewed from the width direction according to a modification of the present invention. DETAILED DESCRIPTION

[0022] An embodiment of a head-up display device according to the present invention will be described with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the head-up display device 100 is mounted on the instrument panel of a vehicle 200. The head-up display device 100 projects display light L onto a windshield 201, serving as a projection target, to display a virtual image V containing vehicle information within a virtual image display area K in a manner that is visually recognizable by a viewer 1 (e.g., the driver of the vehicle 200). When the viewer 1's viewpoints EP1, EP2, and EP3 are within a visible region R, the viewer 1 can visually recognize the virtual image V.

[0024] like Figure 2 As shown, the head-up display device 100 includes a first mirror 11 , a second mirror 12 , a display unit 20 , and a housing 30 .

[0025] The housing 30 is formed into a box shape from a light-shielding resin or metal. The first mirror 11, the second mirror 12, and the display unit 20 are housed within the housing 30. The housing 30 includes a window 31 formed of a light-transmitting member that transmits display light L generated within the interior space of the housing 30 toward the windshield 201.

[0026] The display unit 20 has a light emitting surface 21 that radiates display light L representing an image. The display unit 20 may be a type having a liquid crystal panel and an illumination device, or a type having a reflective display element such as a DMD (Digital Micro Mirror Device) element and a projector. In this example, the display unit 20 radiates the display light L as diffused light. The light emitting surface 21 faces the upper rear side of the vehicle. The image displayed on the light emitting surface 21 is subjected to distortion correction to correct the distortion of the virtual image V visually recognized by the viewer 1.

[0027] like Figure 2 As shown, the first mirror 11 is a curved mirror that is concavely curved along the height of the vehicle and extends linearly along the width of the vehicle. The first mirror 11 can be curved concavely or convexly along the width of the vehicle. The first mirror 11 reflects the display light L emitted from the display unit 20 toward the second mirror 12. The reflective surface 11a of the first mirror 11, which forms the concave curve, faces the lower front side of the vehicle.

[0028] like Figure 3 、 Figure 4 and Figure 5 As shown, the first mirror 11 allows the display unit 20 (see Figure 2 ) is radiated toward the second mirror 12 in a manner that intersects with the intersections CP1, CP2, and CP3 in the height direction of the vehicle 200. The intersections CP1, CP2, and CP3 are located between the first mirror 11 and the second mirror 12 on the optical path of the display light L. The display light L converges from the first mirror 11 to the intersections CP1, CP2, and CP3, and diverges from the intersections CP1, CP2, and CP3 to the second mirror 12. In addition, although a portion of the display light L intersects at the intersections CP1, CP2, and CP3, the position where the display light L is imaged does not necessarily coincide with the position of the intersections. In the head-up display device 100 of the present invention, the display light L is imaged at a position different from the intersection between the first mirror 11 and the second mirror 12 in the height direction.

[0029] The method of setting the positions of the intersection points CP1, CP2, and CP3 will be described in detail later.

[0030] like Figure 2As shown, the second mirror 12 is a concave mirror curved in the height and width directions of the vehicle. The second mirror 12 reflects the display light L reflected from the first mirror 11 toward the windshield 201. The second mirror 12 reflects the display light L from the first mirror 11 toward the windshield 201 in a manner that amplifies the display light L from the first mirror 11. The reflective surface 12a of the second mirror 12, which forms a concave curved surface, faces the upper rear side of the vehicle. The second mirror 12 cooperates with the first mirror 11 to suppress virtual image distortion caused by reflection from the windshield 201.

[0031] Next, refer to Figure 3 、 Figure 4 as well as Figure 5 , while explaining the method of setting the positions of the intersection points CP1, CP2, and CP3.

[0032] The positions of the intersection points CP1, CP2, and CP3 on the optical path of the display light L are adjusted based on, for example, the radius of curvature of the reflective surface 11a of the first mirror 11 and the diffusion angle of the display light L emitted from the display unit 20. For example, the greater the radius of curvature of the reflective surface 11a of the first mirror 11, the closer the intersection points CP1, CP2, and CP3 are to the reflective surface 11a. Furthermore, the greater the diffusion angle of the display light L emitted from the display unit 20, the closer the intersection points CP1, CP2, and CP3 are to the reflective surface 11a. The intersection points CP1, CP2, and CP3 are positioned closer to the first mirror 11 than to the midpoint between the first and second mirrors 11 and 12.

[0033] Specifically, the intersections CP1, CP2, and CP3 will be described.

[0034] like Figure 4 As shown, intersection point CP2 is the location where light rays L2T and L2B of display light L corresponding to viewpoint EP2 located at the upper end of the visual region R in the height direction intersect when viewed from the width direction. Light ray L2T corresponds to the upper end of the virtual image display area K, and light ray L2B corresponds to the lower end of the virtual image display area K.

[0035] like Figure 5 As shown, the intersection point CP3 is the location where light rays L3T and L3B of the display light L corresponding to the viewpoint EP3 located at the upper end of the visual region R in the height direction intersect when viewed from the width direction. Light ray L3T corresponds to the upper end of the virtual image display area K, and light ray L2B corresponds to the lower end of the virtual image display area K.

[0036] like Figure 3As shown, intersection point CP1 is the location where light rays L1T and L1B of display light L, corresponding to viewpoint EP1 located at the upper end of the visual region R in the height direction, intersect when viewed from the width direction. Light ray L1T corresponds to the upper end of the virtual image display area K, and light ray L1B corresponds to the lower end of the virtual image display area K.

[0037] Furthermore, the viewpoints EP1 , EP2 , and EP3 are located at the center of the visible area R in the width direction of the vehicle.

[0038] When viewed two-dimensionally from the width direction, the two light rays L1T, L1B, L2T, L2B, L3T, and L3B that form intersection points CP1, CP2, and CP3, respectively, intersect. However, in reality, light rays L1T, L1B, L2T, L2B, L3T, and L3B extend in three-dimensional space and are not limited to intersecting at intersection points CP1, CP2, and CP3. Therefore, in this example, intersection points CP1, CP2, and CP3 are defined as the intersection points of light rays L1T, L1B, L2T, L2B, L3T, and L3B projected onto plane PL, where the line segments of light rays L2T and L3B are both on the plane.

[0039] like Figure 6 As shown, intersections CP1, CP2, and CP3 are set at positions including a portion of the reflecting surface 11a of the first mirror 11 within an imaginary circle C having a diameter D defined by a line segment connecting the two intersections CP2 and CP3. Intersection CP1 is located at the center of imaginary circle C. Imaginary circle C is determined by experiments or simulations.

[0040] exist Figure 7 In the comparative example of FIG, the intersection points CP1, CP2, and CP3 are set at positions that do not include the reflecting surface 11a of the first mirror 11 within the imaginary circle C. Figure 6 Compared to the present embodiment, the intersection points CP1, CP2, and CP3 are far away from the reflecting surface 11a. In terms of optical path design, it is necessary to form the reflecting surface 11a at a position from the intersection points CP2 and CP3 toward the reflecting surface 11a and from the opposite direction along the direction of travel of the display light L. Therefore, in this comparative example, the size of the reflecting surface 11a needs to be increased. Therefore, the gap S2 between the upper end of the reflecting surface 11a of the first mirror 11 and the display light L reflected by the second mirror 12, especially the light L2T, becomes smaller. Therefore, in this comparative example, the size of the reflecting surface 11a needs to be increased, and various components such as the mirror support member (not shown) of the first mirror 11 may interfere with the optical path of the display light L.

[0041] On the other hand, Figure 6 In this embodiment, Figure 7 Compared with the comparative example, the intersection points CP1, CP2, and CP3 are close to the reflecting surface 11a. Figure 6As shown, the display light L, particularly the light L2T, does not reach the omittable region 11b of the reflective surface 11a, and the display light L, particularly the light L3B, does not reach the omittable region 11c of the reflective surface 11a. Therefore, the omittable regions 11b and 11c can be omitted from the reflective surface 11a, and the size of the reflective surface 11a can be reduced.

[0042] Furthermore, a gap S1 is increased between the upper end of the reflecting surface 11a of the first mirror 11 and the display light L, particularly the light beam L2T, reflected by the second mirror 12. This can prevent various components such as the mirror support (not shown) holding the first mirror 11 from interfering with the optical path of the display light L.

[0043] (Effect)

[0044] According to the embodiment described above, the following effects are achieved.

[0045] (1) The head-up display device 100 projects display light L onto a windshield 201, which is an example of a projection target, so that a virtual image V can be visually recognized by a viewer 1 whose viewpoints EP1, EP2, and EP3 are within a visual region R. The head-up display device 100 includes: a display unit 20 that emits display light L; a first mirror 11 having a reflecting surface 11a that reflects the display light L emitted from the display unit 20; and a second mirror 12 that reflects the display light L reflected by the first mirror 11 toward the projection target 201. The display light L intersects an intersection CP2, which is an example of a first intersection, and an intersection CP3, which is an example of a second intersection, in a height direction, which is an example of a specific direction. A portion of the reflecting surface 11a of the first mirror 11 is contained within an imaginary circle C having a diameter D defined by a line segment connecting the intersection CP2 and the intersection CP3. The intersection point CP2 intersects the display light L corresponding to the viewpoint EP2 at the first end (upper end) of the visible region R in the height direction. The intersection point CP3 intersects the display light L corresponding to the viewpoint EP3 at the second end (lower end) of the visible region R in the height direction.

[0046] According to this configuration, since a portion of the reflective surface 11a of the first mirror 11 is contained within the imaginary circle C, the intersection points CP2 and CP3 are set near the reflective surface 11a of the first mirror 11. Therefore, for the reasons described above, the size of the reflective surface 11a can be reduced. Consequently, the head-up display device 100 can be miniaturized.

[0047] Furthermore, it is possible to suppress interference of various components such as a mirror support (not shown) holding the first mirror 11 with the optical path of the display light L. This improves the degree of freedom in designing the head-up display device 100 .

[0048] (2) The intersection point CP2 and the intersection point CP3 are located between the first mirror 11 and the second mirror 12 on the optical path of the display light L.

[0049] According to this configuration, the head-up display device 100 can be miniaturized.

[0050] The present invention is not limited to the above-described embodiments and drawings. Within the scope of not changing the gist of the present invention, appropriate additions and modifications (including deletion of structural elements) may be made. An example of a modification is described below.

[0051] (Variation)

[0052] In the above embodiment, the intersection points CP1, CP2, and CP3 are set between the first mirror 11 and the second mirror 12 on the optical path of the display light L, but are not limited thereto. Figure 8 As shown, it can also be set between the reflective surface 11a and the light emitting surface 21. In this case, the light emitting surface 21 emits display light L that converges so as to intersect at the intersection points CP1, CP2, and CP3 before reaching the reflective surface 11a. Even in this case, a portion of the reflective surface 11a of the first mirror 11 is included in the imaginary circle C whose diameter D is the line segment connecting the two intersection points CP2 and CP3. This can achieve the same effects as the above embodiment.

[0053] In the above embodiment, the display light L intersects in the height direction of the vehicle 200. However, instead of or in addition to this, the display light L may intersect in the width direction of the vehicle 200. In this case, the reflective surface 11a of the first mirror 11 is formed into a concave shape that curves along the width direction of the vehicle 200. In this modification, the reflective surface 11a is set so that at least a portion of the reflective surface 11a is included in the imaginary circle defined by the intersection point of the intersection in the width direction, using the same method as the above embodiment.

[0054] In the above embodiment, a portion of the reflecting surface 11 a of the first mirror 11 is included in the imaginary circle C when viewed in the width direction. However, the present invention is not limited thereto, and the entire reflecting surface 11 a may be included in the imaginary circle C.

[0055] In addition, in the above embodiment, the positions of the intersection points CP1, CP2, and CP3 are set in a manner that a portion of the reflecting surface 11a of the first mirror 11 is included in the imaginary circle C, but from the same point of view, the positions of the intersection points CP1, CP2, and CP3 can also be set in a manner that a portion of the reflecting surface 11a of the first mirror 11 is included in an imaginary sphere including the imaginary circle C.

[0056] In the above embodiment, the second mirror 12 can also be configured to be rotatable by a mirror drive unit about a rotation axis extending along the width direction of the vehicle. Rotation of the second mirror 12 about the rotation axis allows the position of the display light L irradiated onto the viewer 1 to be adjusted in the height direction. In this case, for example, the intersection points CP1, CP2, and CP3, as well as the imaginary circle C, are determined by the rotation angle of the second mirror 12 at which the irradiation position of the display light L is at the center position in the height direction.

[0057] In the above embodiment, the head-up display device 100 is mounted on a vehicle, but the present invention is not limited thereto and may be mounted on a vehicle such as an airplane or a ship. In addition, the projection target is not limited to the windshield 201 and may be a dedicated combiner.

[0058] The following is a description of the reference numerals.

[0059] 1: Visual identifier; 11: First mirror; 11a, 12a: Reflecting surface; 11b, 11c: Omittable area; 12: Second mirror; 20: Display unit; 21: Light emitting surface; 30: Housing; 100: Head-up display device; 200: Vehicle; 201: Windshield; C: Imaginary circle; D: Diameter; K: Virtual image display area; L: Display light; R: Visible area; S1, S2: Gap; V: Virtual image; L1B, L2B, L3B, L1T, L2T, L3T: Light rays; CP1, CP2, CP3: Intersection points; EP1, EP2, EP3: Viewpoints; PL: Plane.

Claims

1. A head-up display device, characterized in that: A head-up display device projects display light onto a projection target component so that a virtual image can be visually recognized by a viewer whose viewpoint is within a visible area, and comprises: a display portion that radiates the display light; a first mirror having a reflecting surface for reflecting the display light emitted from the display portion; as well as a second mirror that reflects the display light reflected by the first mirror toward the projected component; The display light intersects at a first intersection point and a second intersection point in a determined direction, At least a portion of the reflecting surface of the first mirror, which is formed into a concave curved surface at least along the height direction or the width direction of the vehicle, is included in an imaginary circle having a line segment connecting the first intersection point and the second intersection point as a diameter. The first intersection point is a point where the display light intersects with a viewpoint corresponding to a first end of the visible area in the determined direction. The second intersection point is a point where the display light intersects with a viewpoint at a second end portion of the visible area on the opposite side to the first end portion in the specific direction.

2. The head-up display device according to claim 1, wherein: The first intersection point and the second intersection point are located between the first mirror and the second mirror on the optical path of the display light.

3. The head-up display device according to claim 1, wherein: The first intersection point and the second intersection point are located between the display unit and the first mirror on the optical path of the display light.

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