Head-up display device

Abstract

To provide a head-up display device capable of reducing the distortion of the displayed virtual image while reducing the load on a control unit.SOLUTION: A head-up display 100 that displays virtual images V1 and V2 by emitting display light L to a windshield 201 mounted on a vehicle 200, includes: a display unit 20 having a display surface 21 that emits display light L; and a prism 40 through which the display light L emitted from the display surface 21 passes. The prism 40 includes: an entrance surface 41i into which the display light L from the display surface 21 is incident; and an output surface 41o that outputs the display light L that enters the prism 40 from the input surface 41i.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a head-up display device.

Background Art

[0002] For example, the display device described in Patent Document 1 displays an image on a display unit based on the control of a control unit. At this time, the control unit outputs pre-distorted image data to the display unit based on warping parameters stored in a storage device so as to cancel out the distortion generated by an optical member that projects display light. When the control unit performs control on a display unit capable of 3D display, the control unit also controls warping in the depth direction.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration described in Patent Document 1 above, since the control unit generates a distorted image each time based on warping parameters, the resources required for calculation tend to increase.

[0005] The present disclosure has been made in view of the above actual situation, and an object thereof is to provide a head-up display device capable of reducing the distortion of a virtual image while reducing the load on the control unit.

Means for Solving the Problems

[0006] To achieve the above object, a head-up display device according to the present disclosure is a head-up display device that displays a virtual image by emitting display light to a transmissive-reflective member mounted on a vehicle, A display device having a display surface that emits the aforementioned display light, The system comprises a prism through which the display light emitted from the display surface is transmitted, The prism mentioned above is An incident surface into which the display light from the display surface is incident, The system comprises an emission surface that emits the display light that has been incident on the prism from the incidence surface, Between the incident surface and the exit surface, a virtual display surface is formed, which is the apparent position of the display surface caused by refraction at the exit surface. The aforementioned virtual display surface is It is formed to reduce the distortion of the virtual image in the depth direction caused by reflection in the aforementioned transmissive reflective member. 、 The aforementioned ejection surface is, A first top surface extending in a direction along the display surface, The system comprises an inclined surface that is inclined with respect to the first top surface,

[0007] To achieve the above objectives, the head-up display device relating to this disclosure is A head-up display device that displays a virtual image by emitting display light onto a transmissive reflective member mounted on a vehicle, A display device having a display surface that emits the aforementioned display light, The system comprises a prism through which the display light emitted from the display surface is transmitted, The prism mentioned above is An incident surface into which the display light from the display surface is incident, The system comprises an emission surface that emits the display light that has been incident on the prism from the incidence surface, Between the incident surface and the exit surface, a virtual display surface is formed, which is the apparent position of the display surface caused by refraction at the exit surface. The emission surface has a convex shape that is symmetrical in the direction corresponding to the width direction of the virtual image. death, A first top surface extending in a direction along the display surface, The system comprises an inclined surface that is inclined with respect to the first top surface, [Effects of the Invention]

[0008] According to the present disclosure, in a head-up display device, it is possible to reduce the distortion of a virtual image to be displayed while reducing the load on a control unit.

Brief Description of Drawings

[0009] [Figure 1] It is a schematic diagram of a head-up display device according to a first embodiment of the present disclosure. [Figure 2] It is a diagram showing a virtual image overlapping with an actual landscape according to a first embodiment of the present disclosure. [Figure 3] It is a perspective view of a prism and a display according to a first embodiment of the present disclosure. [Figure 4] It is a longitudinal sectional view of a prism and a display according to a first embodiment of the present disclosure. [Figure 5] It is a side view of a prism and a display according to a first embodiment of the present disclosure. [Figure 6] It is a schematic diagram of a display, a prism, a concave mirror, and a windshield according to a first embodiment of the present disclosure. [Figure 7] It is a schematic diagram of a display, a concave mirror, and a windshield according to a comparative example.

Embodiments for Carrying Out the Invention

[0010] (First Embodiment) A head-up display device according to a first embodiment of the present disclosure will be described with reference to the drawings. As shown in Figure 1, the head-up display device 100 is mounted under the dashboard of the vehicle 200. The head-up display device 100 displays multiple virtual images V1 and V2 containing vehicle information by projecting display light L onto a windshield 201, which is an example of a projection target member (transmissive reflective member). When the viewer's viewpoint EP is within the visible area R, the viewer 1 can see the virtual images V1 and V2. Virtual image V1 is displayed within the virtual image display virtual area K1. Virtual image V2 is displayed within the virtual image display virtual area K2. The multiple virtual image display virtual areas K1 and K2 are each formed by an intangible surface and are formed in different orientations from each other.

[0011] The virtual image display area K1 extends along the height direction. Here, "along the height direction" means that the virtual image display area K1 is less than ±45° with respect to the height direction. The virtual image display area K2 exists below the virtual image display area K1, and is inclined. For example, the virtual image display area K2 follows the road surface. Here, "following the road surface" means that the virtual image display area K2 is less than ±45° with respect to the horizontal direction.

[0012] As shown in Figure 2, the virtual image V2 is displayed along the road surface, which is the actual scenery as seen by the viewer 1. The virtual image V1 is displayed as if it is erected on the road surface, which is the actual scenery as seen by the viewer 1. The virtual image V2 contains information associated with the road surface, such as symbolic information such as route guidance arrows. The virtual image V1 contains textual information or sign information such as vehicle speed. Text includes numbers, alphabets, hiragana, katakana, kanji, etc. Furthermore, the virtual image V1 may include icons representing structures erected on the ground, such as buildings or trees. By comparing it with these icons, it becomes easier for the viewer 1 to recognize that the display of the virtual image V1, excluding these icons, is also displayed along the height direction.

[0013] Next, the configuration of the head-up display device 100 will be described. As shown in Figure 1, the head-up display device 100 comprises a concave mirror 12 which is an optical relay, a display unit 20, a control unit 25, a case 30, and a prism 40 which is an example of a virtual image orientation adjustment means.

[0014] The case 30 is formed in a box shape from a light-shielding resin or metal. Inside the case 30 are a concave mirror 12, a display unit 20, and a prism 40. The case 30 is provided with a window portion 31 made of a light-transmitting material that transmits the display light L generated in the internal space of the case 30 toward the windshield 201.

[0015] The display unit 20 has a display surface 21 that emits display light L representing an image. The display unit 20 may be of a type that has a liquid crystal panel and a lighting device, or it may be of a type that has a reflective display element such as a DMD (Digital Micro Mirror Device) element and a projector. The display surface 21 faces the front and lower side of the vehicle 200. The image displayed on the display surface 21 is subjected to distortion correction to correct distortion that occurs in the in-plane direction of the virtual images V1 and V2 seen by the viewer 1. This distortion correction is called warping. The display surface 21 is inclined with respect to the optical axis center La of the display light L. The optical axis center La is located at the center of the cross-section of the display light L.

[0016] As shown in Figure 4, the display surface 21 has a first region 2 that emits display light L corresponding to the virtual image V1. It comprises 0a and a second region 20b that emits display light L corresponding to the virtual image V2. Character information is displayed in area 20a, and symbolic information is displayed in the second area 20b. A first virtual display surface and a second virtual display surface are formed in the internal space of the prism 40 corresponding to the first area 20a and the second area 20b, respectively.

[0017] As shown in Figure 1, the control unit 25 includes a CPU (Central Processing Unit), a GDC (Graphics Display Controller), a ROM (Read Only Memory), and a RAM (Random Access Memory), etc. The control unit 25 acquires information related to vehicle speed and route guidance from an external source and generates an image to be displayed on the display surface 21 based on this information.

[0018] The prism 40 is installed on the display surface 21, and the display light L emitted from the display surface 21 passes through it. The prism 40 will be described in detail later.

[0019] As shown in Figure 1, the concave mirror 12 has a reflective surface 12a that curves concavely along the height and width directions of the vehicle. The concave mirror 12 reflects the display light L transmitted through the prism 140 toward the windshield 201. The concave mirror 12 reflects toward the windshield 201 in a way that amplifies the display light L from the display surface 21. The reflective surface 12a of the concave mirror 12 faces the rear upper side of the vehicle 200. The concave mirror 12 has the function of suppressing distortion of the virtual image caused by reflection at the windshield 201.

[0020] Next, I will explain the configuration of the prism 40. As shown in Figures 3 and 4, the prism 40 is made of a material whose refractive index n is greater than that of air (n=1), such as glass or optical resin. The prism 40 is formed in a roughly plate-like shape that covers the display surface 21.

[0021] The prism 40 is positioned opposite the display surface 21 and includes an incident surface 41i into which display light from the display surface 21 is incident, and an exit surface 41o positioned on the opposite side of the incident surface 41i and which emits the incident display light L. The incident surface 41i is formed in a rectangular planar shape. The incident surface 41i of the prism 40 may be fixed to the display surface 21 by optical bonding, or the prism 40 may be supported by a support mechanism (not shown).

[0022] The prism 40 and the display unit 20 are plate-shaped and elongated in the height direction. The prism 40 is positioned corresponding to the display surface 21 and includes an incident surface 41i into which display light from the display surface 21 is incident, and an exit surface 41o into which the display light L incident on the prism 40 via the incident surface 41i is emitted. The exit surface 41o includes a first top surface 42 which is semi-cylindrical and extends along the display surface 21, and an inclined surface 43 which is semi-cylindrical and inclined with respect to the first top surface 42. The first top surface 42 and the inclined surface 43 are continuous in the height direction. The first top surface 42 is located above the inclined surface 43. The inclined surface 43 is inclined so as it goes downwards, it approaches the display unit 20. The semi-cylindrical shapes of the first top surface 42 and the inclined surface 43 are convex in the direction opposite to the display unit 20. In other words, the first top surface 42 and the inclined surface 43 have a curved shape that is convex in the direction from which the display light L is emitted.

[0023] A first virtual display surface 48A and a second virtual display surface 48B are formed on the prism 40, located at the center in the thickness direction of the prism 40. Due to its refractive index n, the prism 40 makes the display surface 21 function as if it were located on the first virtual display surface 48A and the second virtual display surface 48B. Thus, the prism 40 enables a single display surface 21 to function as if it were multiple display surfaces. The first virtual display surface 48A is located between the first top surface 42 and the incident surface 41i and is formed in a planar shape similar to the first top surface 42. The second virtual display surface 48B is formed between the inclined surface 43 and the incident surface 41i. The second virtual display surface 48B extends so as to bisect the angle α made by the incident surface 41i and the inclined surface 43. The first virtual display surface 48A corresponds to the virtual image display virtual region K1. The second virtual display surface 48B corresponds to the virtual image display virtual region K2.

[0024] The optical axis center La of the display light L passes through the boundary between the first virtual display surface 48A and the second virtual display surface 48B. Alternatively, the optical axis center La of the display light L may pass through both the first virtual display surface 48A and the second virtual display surface 48B without passing through the boundary.

[0025] The angle θ1 of the extension of the first virtual display surface 48A with respect to the optical axis center La (shown by the dashed line in Figure 4) is smaller than the angle θ2 of the second virtual display surface 48B with respect to the optical axis center La. As the angle θ2 (see Figure 4) increases, the inclination angle of the virtual image display area K2 with respect to the height increases.

[0026] As shown in Figures 1 and 4, the first virtual display surface 48A corresponds to a virtual image display area K1 that is aligned with the height direction. The second virtual display surface 48B corresponds to a virtual image display area K2 that is inclined with respect to the virtual image display area K1. The upper end of the first virtual display surface 48A corresponds to the lower end of the virtual image display area K1, and the lower end of the second virtual display surface 48B corresponds to the upper end of the virtual image display area K2. That is, the images on the first virtual display surface 48A and the second virtual display surface 48B are inverted in the height direction and the vehicle's front-to-rear direction and displayed as virtual images V1 and V2, respectively. As shown in Figures 1 and 2, the virtual image display area K2 is located above the virtual image display area K1 as viewed from the viewer 1. The upper end of the virtual image display area K1 is in contact with the lower end of the virtual image display area K2. The virtual image display area K2 slopes upward as it moves away from the viewer 1.

[0027] (Regarding the shape of the top surface) Figure 5 shows the appearance of the prism 40 and the display unit 20 in a plan view from the height direction. The emission surface 42o has a first top surface 42 that has a curved shape from this viewpoint. Up to this point, the virtual display surfaces 48A and 48B have been described based on their shape in a plan view from the vehicle width direction. However, the actual virtual display surfaces 48A and 48B have a curved shape as shown by the dotted lines in the drawing due to the action of the shapes of the first top surface 42 and the inclined surface 43.

[0028] Here, with reference to Figure 7, the conventional configuration will be described. Figure 7 is a schematic diagram showing the configuration of a head-up display comprising a display unit 20, a concave mirror 12, and a windshield 201 when viewed vertically downwards. This head-up display does not include a prism 40.

[0029] The display light L is emitted from the display unit 20, which has a rectangular display surface. The display light L is reflected by the concave mirror 12 and the windshield 201 before reaching the visible region. At the same time, a virtual image Vo, visible from the visible region, is formed in front of the windshield 201.

[0030] In this case, as shown in Figure 7, the virtual image Vo is formed with a curved shape as indicated by the dotted line in the drawing. Specifically, when reflected by a concave mirror 12 and a windshield 201, both of which have concave reflective surfaces, the ends of the virtual image Vo are formed closer to the visible region compared to the center position. This occurs because, when comparing the inner optical path length with the outer optical path length, the outer optical path length becomes extremely short when the concave mirror 12 and the windshield 201, both with concave reflective surfaces, are grounded facing each other. In this way, even if the display surface is flat, the virtual image does not necessarily form as a flat plane, and distortion in the depth direction of the virtual image may occur.

[0031] While conventional technologies have existed that reduce in-plane distortion of virtual images by warping the image displayed on the display, it has been difficult to reduce distortion in the depth direction of virtual images unless a display capable of 3D display is used.

[0032] Therefore, in this disclosure, the head-up display device is configured as in this embodiment. Specifically, in the head-up display device 100, Prism 40 is, The incident surface 41i into which the display light L from the display surface 21 is incident, It comprises an output surface 41o that emits the display light L that has been incident on the prism 40 from the input surface 41i, Between the incident surface 41i and the exit surface 41o, virtual display surfaces 48A and 48B are formed, which are the apparent positions of the display surface 21 caused by refraction at the exit surface 41o. Virtual display surfaces 48A and 48B are, It is shaped to reduce the depth-direction distortion of virtual images V1 and V2 caused by reflection from the windshield 201.

[0033] In the first embodiment, the virtual display is convex in the direction of the output of the display light L due to the action of the prism 40 (i.e., convex toward the visible region R). Since the virtual image should be distorted to be concave toward the visible region R due to reflection from optical relays other than the prism (concave mirror 12 and windshield 201), such a head-up display can reduce the distortion in the depth direction of the virtual images V1 and V2.

[0034] From another perspective, in the head-up display device 100, Prism 40 is, The incident surface 41i into which the display light L from the display surface 21 is incident, It comprises an output surface 41o that emits the display light L that has been incident on the prism 40 from the input surface 41i, Between the incident surface 41i and the exit surface 41o, virtual display surfaces 48A and 48B are formed, which are the apparent positions of the display surface 21 caused by refraction at the exit surface 41o. The emission surface 41o has a convex shape in a direction corresponding to the width direction of the virtual images V1 and V2.

[0035] In the first embodiment, the virtual display is convex in the direction of the emission of the display light L due to the action of the prism 40 (i.e., convex toward the visible region R). Since the virtual image should be distorted to be concave toward the visible region R due to reflection from optical relays other than the prism (concave mirror 12 and windshield 201), such a head-up display can reduce distortion in the depth direction of the virtual images V1 and V2. It is even better if this convex shape is symmetrical in the direction corresponding to the width direction. With this configuration, common components can be used regardless of whether the vehicle is right-hand drive or left-hand drive, resulting in a head-up display device with excellent manufacturability.

[0036] Furthermore, if the virtual images V1 and V2 have a convex shape that is symmetrical in the direction corresponding to the width direction, a common prism 40 can be used even if the steering wheel position of the vehicle 200 is shifted to the left or right relative to the center, making it particularly suitable as a head-up display mounted on a vehicle.

[0037] This disclosure is not limited to the embodiments and drawings described above. Modifications (including the deletion of components) can be made as appropriate, provided they do not alter the essence of this disclosure. An example of such a modification is described below.

[0038] (modified version) In the above embodiment, a prism 40 equipped with an inclined surface 43 is shown, but the invention is not limited to this, and the entire emission surface 41o may be composed of the first top surface 42.

[0039] In the above embodiment, the first top surface 42 and the inclined surface 43 are curved surfaces with uniform curvature, but the invention is not limited to this, and the curvature may be changed partially or entirely. In particular, the curvature of a windshield is generally relatively larger at the top. Therefore, if the curvature of the exit surface 41o is also high in the portion corresponding to that area, distortion can be reduced more effectively.

[0040] In the above embodiment, the display light L was directly irradiated from the display surface 21 to the concave mirror 12. However, the invention is not limited to this, and a corrective mirror or a flat mirror may be newly provided to reflect the display light L irradiated from the display surface 21 toward the concave mirror 12. This corrective mirror is, for example, a concave mirror with a concave vertical cross-section. This corrective mirror and the concave mirror 12 may constitute an optical relay that guides the display light L from the display surface 21 to the windshield 201.

[0041] In each of the above embodiments, the concave mirror 12 may be configured to rotate around a rotation axis extending in the vehicle width direction. By rotating the concave mirror 12 around this rotation axis, the height at which the display light L is projected to the viewer 1 is adjusted.

[0042] In the above embodiment, the display surface 21 may be configured so that display light L is not emitted from the non-display area 21a corresponding to the boundary portion of the virtual display surfaces 48A and 48B. This suppresses the display from moving between virtual images V1 and V2 when the viewer's viewpoint moves within the visible area, thereby reducing the discomfort caused to the viewer. It should be noted that the configuration is not limited to this modification, and a light-shielding means such as a light-shielding member may be used to prevent display light L from reaching the boundary portion of the virtual display surfaces 48A and 48B.

[0043] The prism 40 may be made of urexite, or television stone. This makes it possible to form a virtual display surface on the light-emitting surface of the prism 40.

[0044] The prism 40A may have an overhang portion 49 that extends beyond the display surface 21, as shown by the dashed line in Figure 4. The overhang portion 49 transmits the light L from the display surface 21 toward the upper end of the concave mirror 12. The overhang portion 49 is provided on the upper surface of the prism 40 in the above embodiment and is formed so that its height increases as it approaches the emission surface 41o from the display surface 21. This allows the entire reflective surface 12a of the concave mirror 12 to be effectively utilized, and the size of the virtual image display area K1 can be increased. Furthermore, the edge portion between the top surface and the inclined surface of the prism 40 may be rounded. The top surface and the inclined surface of the prism 40 described above may be formed separately.

[0045] In the embodiments described above, the head-up display device 100 was mounted in a vehicle, but it is not limited to this and may be mounted in other vehicles such as airplanes or ships. Furthermore, the projected element is not limited to the windshield 201, but may be a dedicated combiner. Furthermore, the display light L may cross within the optical path due to the converging action of mirrors or lenses. Even in this case, the effects of the present invention are realized when prisms and indicators are appropriately configured to correspond to the desired virtual image shape. For example, if the indicator light L crosses once in the vertical direction within the optical path, it is preferable to install the prism and indicator inverted vertically compared to the case where it does not cross. [Explanation of symbols]

[0046] 1. Sighted person 12 Concave mirror 20 Display 21 Display surface 21a Hidden area 25 Control Unit 30 cases 31 Window section 40 prisms 41i entrance plane 41o Output surface 42 First Top Surface 43 Slope 48A, 48B Virtual display surface 49. Protruding part 100 Head-Up Display Devices 200 vehicles 201 Windshield 205 Viewpoint detection unit α, θ1, θ2 angles C center line L display light K1, K2 Virtual Image Representation Virtual Region R visible range V1, V2 virtual images X horizontal axis Z vertical axis EP perspective La optical axis center

Claims

1. A head-up display device that displays a virtual image by emitting display light onto a transmissive reflective member mounted on a vehicle, A display device having a display surface that emits the aforementioned display light, The system comprises a prism through which the display light emitted from the display surface is transmitted, The prism mentioned above is An incident surface into which the display light from the display surface is incident, The system comprises an emission surface that emits the display light that has been incident on the prism from the incidence surface, Between the incident surface and the exit surface, a virtual display surface is formed, which is the apparent position of the display surface caused by refraction at the exit surface. The aforementioned virtual display surface is It is formed to reduce the distortion of the virtual image in the depth direction caused by reflection in the aforementioned transmissive reflective member, The aforementioned ejection surface is, A first top surface extending in a direction along the display surface, The system comprises an inclined surface that is inclined with respect to the first top surface, Head-up display device.

2. A head-up display device that displays a virtual image by emitting display light onto a transmissive reflective member mounted on a vehicle, A display device having a display surface that emits the aforementioned display light, The system comprises a prism through which the display light emitted from the display surface is transmitted, The prism mentioned above is An incident surface into which the display light from the display surface is incident, The system comprises an emission surface that emits the display light that has been incident on the prism from the incidence surface, Between the incident surface and the exit surface, a virtual display surface is formed, which is the apparent position of the display surface caused by refraction at the exit surface. The emission surface has a convex shape in a direction corresponding to the width direction of the virtual image, A first top surface extending in a direction along the display surface, The system comprises an inclined surface that is inclined with respect to the first top surface, Head-up display device.

3. The emission surface has a convex shape that is symmetrical in the direction corresponding to the width direction of the virtual image. The head-up display device according to claim 2.

4. The display surface is A first region that emits the display light passing through the first top surface, It comprises a second region that emits the display light passing through the inclined surface, Text information is displayed in the first area. Symbolic information is displayed in the second area. The head-up display device according to claim 1 or 2.

5. A first virtual display surface is formed between the first top surface and the incident surface of the prism, A second virtual display surface is formed between the inclined surface and the incident surface of the prism. The display surface includes a non-display area that hides the area corresponding to the boundary between the first virtual display surface and the second virtual display surface. The head-up display device according to claim 1 or 2.

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