Head-up display

Abstract

By using a common image generation device for both the left and right sides, we provide a head-up display that can suppress the soaring manufacturing costs of head-up displays. [Solution] The head-up display 1 is a head-up display 1 that forms a virtual image by projecting display light onto a display medium, and comprises a housing to which a reflective mirror 30 and a display element 21 are attached. The display element 21 emits display light that becomes a projected image on the display medium by displaying an image, the reflective mirror 30 reflects the display light toward the display medium, and the housing is formed as a resin injection molded body. If the parting line surface P formed by the cavity and core of the housing mold for forming the housing is defined as the X-axis direction, and the direction along the display surface 21a of the display element 21 corresponding to the left-right direction of the virtual image is defined as the X-axis direction, then the housing is mounted such that the parting line surface P and the X-axis direction are substantially parallel.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a plane mirror unit that is mounted on a vehicle and capable of projecting an image. This plane mirror unit is provided in a head-up display device that displays an image as a virtual image by emitting display light representing an image emitted by a display from an emission port toward a light-transmissive member located outside a case.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] For example, there is a demand for commonizing the left and right sides of an image generation device such as a PGU (Picture Generation Unit) of a head-up display mounted on a vehicle so as to be compatible with left-hand drive and right-hand drive vehicles. In this case, it is also required that the fastening shape for fastening the housing of the image generation device to the main housing of the head-up display be symmetrical in the left-right direction. In this case, since the image generation device is inclined with respect to the parting line surface of the cavity and core of the mold used for forming the main housing, the cavity and core of the mold may not be configured as an upper-lower split mold. In this case, the mold has to be made as a slidable split mold, or a mold for the left-hand drive and a mold for the right-hand drive for the housing of the image generation device have to be manufactured. For this reason, there is a problem that the mold cost rises, and the manufacturing cost of the head-up display increases.

[0005] Therefore, the purpose of this disclosure is to provide a head-up display that can suppress the soaring manufacturing costs of head-up displays by making the image generation device common to both the left and right sides. [Means for solving the problem]

[0006] A head-up display according to one aspect of the present disclosure is a head-up display that forms a virtual image by projecting display light onto a display medium, and comprises a reflective mirror and a housing on which a display element is mounted, wherein the display element emits the display light which becomes a projected image on the display medium by displaying an image, the reflective mirror reflects the display light toward the display medium, the housing is formed as a resin injection molded body, and the parting line surface formed between the cavity and core of the housing mold for forming the housing and the direction along the display surface of the display element corresponding to the left-right direction of the virtual image are defined as the X-axis direction, and the housing is mounted such that the parting line surface and the X-axis direction are substantially parallel. [Effects of the Invention]

[0007] In the head-up display disclosed herein, the rising manufacturing costs of the head-up display can be suppressed by using the same image generation device for both the left and right sides. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view showing a head-up display according to an embodiment mounted in a vehicle. [Figure 2] Figure 2 is a cross-sectional view showing the windshield and head-up display. [Figure 3] Figure 3 is a plan view looking down at the housing and image generation device of a head-up display according to an embodiment mounted on a vehicle. [Figure 4A] Figure 4A is a cross-sectional view showing the housing and image generation device along line BB in Figure 3. [Figure 4B]Figure 4B is a cross-sectional view showing the housing and image generation device in the prior art. [Figure 5A] Figure 5A is a cross-sectional view showing the image generation device in the case where the housing is omitted, along line AA in Figure 3. [Figure 5B] Figure 5B shows the relationship between the light-emitting module and the illumination lens. [Figure 6A] Figure 6A shows the orientation of the display surface of the display element. [Figure 6B] Figure 6B shows the relationship between the reflective mirror and the image generation device in a head-up display. [Figure 7] Figure 7 shows the image displayed on the display surface. [Figure 8] Figure 8 shows the relationship between the reflective mirror and the image generation device in a head-up display. [Figure 9] Figure 9 shows an image generation device using a light guide plate. [Figure 10] Figure 10 shows the symmetry between the multiple lenses formed on the light guide plate and the multiple light sources. [Figure 11] Figure 11 shows the relationship between the display light projected onto the windshield and the virtual image when the head-up display of this implementation is mounted on the left and right sides of the vehicle, respectively. [Modes for carrying out the invention]

[0009] The embodiments will be described in detail below with reference to the drawings.

[0010] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples only and are not intended to limit this disclosure. Furthermore, any components in the following embodiments that are not described in an independent claim will be described as optional components.

[0011] Further, each drawing is a schematic diagram and is not necessarily strictly illustrated. Therefore, for example, scales and the like in the respective drawings do not necessarily match. In the respective drawings, substantially the same configurations are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

[0012] In the following embodiments, the front-rear direction of the vehicle is synonymous with the full length direction of the vehicle, and the left-right direction of the vehicle is synonymous with the width direction of the vehicle. The front direction of the vehicle is the front direction when a user is seated in the driver's seat. The rear direction of the vehicle is the direction opposite to the front direction of the vehicle. The right direction of the vehicle is the right direction when the user is seated in the driver's seat. The left direction of the vehicle is the direction opposite to the right direction of the vehicle.

[0013] Further, in the following embodiments, expressions such as front direction, rectangular shape, and substantially parallel are used. For example, the front direction not only means a complete front direction, the rectangular shape means a complete rectangular shape, and substantially parallel means completely parallel, but also means substantially front direction, substantially rectangular, and substantially parallel, that is, including an error of, for example, about several percent. In addition, the front direction, the rectangular shape, and the substantially parallel mean the X-axis direction, the rectangular shape, and the substantially parallel within a range where the effects according to the present disclosure can be achieved. The same applies to other expressions using "direction", "shape", and "substantially".

[0014] (Embodiment) <Configuration> Hereinafter, the head-up display 1 of the present disclosure will be specifically described with reference to FIGS. 1 to 11.

[0015] FIG. 1 is a perspective view showing a head-up display according to an embodiment mounted on a vehicle 2. FIG. 2 is a cross-sectional view showing a windshield 3 and the head-up display 1. FIG. 3 is a plan view of the housing and the image generation device 20 of the head-up display 1 according to the embodiment mounted on the vehicle 2 when viewed from above. FIG. 4A is a cross-sectional view showing the housing and the image generation device 20 taken along line B-B in FIG. 3. FIG. 4B is a cross-sectional view showing the housing and the image generation device 20 in the related art. FIG. 5A is a cross-sectional view showing the image generation device 20 with the housing omitted, taken along line A-A in FIG. 3. FIG. 5B is a diagram showing the relationship between the light emitting module 22 and the illumination lens 23. FIG. 6A is a diagram showing the direction of the display surface 21a of the display element 21. FIG. 6B is a diagram showing display light emitted from the image generation device in the head-up display. FIG. 7 is a diagram showing an image displayed on the display surface 21a. FIG. 8 is a diagram showing the relationship between the reflection mirror 30 and the image generation device 20 in the head-up display 1. FIG. 9 is a diagram showing the image generation device 20 using a light guide plate 122. FIG. 10 is a diagram showing the symmetry between the plurality of lenses formed on the light guide plate 122 and the plurality of light sources 22a. FIG. 11 is a diagram showing the relationship between display light projected onto the windshield 3 and a virtual image when the head-up display 1 of the present embodiment is mounted on each of the left side and the right side of the vehicle 2.

[0016] First, a schematic configuration of the head-up display 1 will be described.

[0017] As shown in FIG. 1 and FIG. 2, the head-up display 1 is disposed, for example, on a dashboard 5 (also referred to as an instrument panel) of a vehicle 2 traveling on a traveling surface. A windshield 3 is disposed above the dashboard 5 of the vehicle 2. The head-up display 1 is disposed inside the dashboard 5.

[0018] The head-up display 1 is mounted on the vehicle 2, and can project an image onto a display medium that can transmit and reflect display light, and form a virtual image on the side opposite to the observer with respect to the display medium.

[0019] For example, the head-up display 1 can display a virtual image represented by the display light to an observer, such as a user, by reflecting the display light representing the image emitted from the image generation device 20 onto a display medium such as the windshield 3 or a translucent combiner. In other words, the head-up display 1 can display the image represented by the display light on the windshield 3 by projecting the display light emitted from the image generation device 20 onto the windshield 3. As a result, the image projected onto the windshield 3 of the vehicle 2 is visible to the observer. Figures 1 and onward of this embodiment illustrate the case in which the head-up display 1 projects the display light onto the windshield 3.

[0020] Here, the display light is light that shows a projected image including numbers, letters, and figures, and is displayed as a virtual image in front of the windshield 3. The projected image can be a still image or a moving image, and is an image of numbers, letters, and figures.

[0021] As shown in Figures 2 and 3, the head-up display 1 comprises a housing 10, one or more reflective mirrors 30, and an image generation device 20.

[0022] The housing 10 is a housing that accommodates the image generation device 20 and one or more reflective mirrors 30. The housing 10 is made of resin material or the like and constitutes the outer shell of the head-up display 1. The housing 10 is fixed to the vehicle 2 while attached to the dashboard 5. A housing opening is formed on the upper side of the housing 10 to allow display light to pass through and be emitted to the outside. A dust cover 40 is placed in the housing opening. The housing 10 is an example of a housing.

[0023] The housing 10 includes an inner cover 13, a first housing 11, and a second housing 12.

[0024] The inner cover 13 is housed in the first housing 11 and the second housing 12, and is positioned to divide the internal space of the first housing 11 and the second housing 12 into an upper space and a lower space. The inner cover 13 can suppress stray light from the display light emitted by the image generation device 20, external light incident from outside the head-up display 1, etc.

[0025] The first housing 11 and the second housing 12 are housings that contain an inner cover 13, an image generating device 20, and one or more reflective mirrors 30. The first housing 11 and the second housing 12 form the outer shell of the head-up display 1.

[0026] The first housing 11 is a bottomed container fixed to the vehicle 2 when attached to the dashboard 5. A first connecting opening for connecting to the second housing 12 is formed on the upper side of the first housing 11. The first connecting opening is provided to correspond to the shape and position of the second connecting opening formed on the lower side of the second housing 12.

[0027] The second housing 12 is rectangular in shape and is a frame-like body with a rectangular housing opening formed in the center that allows display light to pass to the outside. A dust cover 40 is placed over the housing opening, and the dust cover 40 covers the housing opening.

[0028] The first connecting opening of the first housing 11 and the second connecting opening of the second housing 12 are aligned, and the second housing 12 is attached to the first housing 11. Specifically, the engaging portion of the second housing 12 engages with the engaged portion of the first housing 11. In this way, the first housing 11 and the second housing 12 are connected and form a housing.

[0029] As shown in Figure 4A, the first housing 11 and the second housing 12 are each formed as resin injection molded bodies. For example, in the housing mold of an injection molding machine, a cavity, which is the movable side, and a core, which is the fixed side, are designed and prepared. By overlapping the cavity and the core, a molding space for molding the housing 10 is formed. Resin flows into the molding space by being injected through the gate of the cavity. As the resin hardens, the first housing 11 and the second housing 12, which are resin injection molded bodies with the shape of the molding space transferred onto them, can be obtained. At this time, a parting line, which is the joint between the cavity and the core, is generated when the resin injection molded bodies are molded.

[0030] The parting line is substantially parallel to the longitudinal and lateral directions of the vehicle 2. A parting line surface P parallel to the parting line is formed on each of the first housing 11 and the second housing 12. The parting line surface P is substantially parallel to the plane formed by the longitudinal and lateral directions of the vehicle 2. In this embodiment, the parting line surface P of the head-up display 1 mounted on the vehicle 2 is substantially parallel to the horizontal plane when the vehicle 2 is placed on a horizontal surface.

[0031] Here, the longitudinal direction of vehicle 2 is approximately parallel to the longitudinal direction of vehicle 2. The lateral direction of vehicle 2 is approximately parallel to the lateral direction of vehicle 2.

[0032] As shown in Figure 4B, in the conventional technology, the parting line surface P is inclined and non-parallel to the left-right direction of the vehicle. Therefore, in the conventional technology, the parting line surface P is non-parallel to the planes formed by the front-rear and left-right directions of the vehicle. Consequently, if the removal direction of the housing mold in the injection molding machine is parallel to the upward direction, undercuts occur when molding the housing in the conventional technology.

[0033] However, in the housing 10 of this embodiment, the parting line surface P and the left-right direction are substantially parallel, so no undercut occurs. As a result, in this embodiment, the increase in manufacturing costs can be suppressed compared to the housing of Figure 4B.

[0034] One or more reflective mirrors 30 of such a head-up display 1 include a first reflective mirror 31, as shown in Figure 2.

[0035] The first reflective mirror 31 and the image generating device 20 are arranged in the housing 10 so as to face each other at a predetermined distance apart. Specifically, the first reflective mirror 31 is positioned on the front side of the housing 10 of the vehicle 2 so as to face the display surface 21a of the image generating device 20, which is located on the rear side of the housing 10 of the vehicle 2. As a result, the first reflective mirror 31 can reflect the display light emitted by the image generating device 20 towards the windshield 3 via the dust cover 40.

[0036] The first reflective mirror 31 is a concave mirror having a free-form surface. In this embodiment, the first reflective mirror 31 is a rectangular mirror that is elongated in the left-right direction of the vehicle 2. The shape of the first reflective mirror 31 is not particularly limited and may be polygonal or circular.

[0037] Furthermore, the first reflective mirror 31 may be able to swing about the left-right axis of the vehicle 2. In this case, the position of the virtual image projected onto the windshield 3 can be adjusted. The first reflective mirror 31 may be able to swing by manual operation or by electric operation by a drive mechanism.

[0038] The image generation device 20 can generate an image and output display light indicating the generated image so that it is projected onto the windshield 3. Specifically, the image generation device 20 emits display light from the display element 21. The display light emitted from the display element 21 of the image generation device 20 is reflected by the first reflective mirror 31, passes through the dust cover 40, and is then emitted from the head-up display 1 to be projected onto the windshield 3. In other words, the image generation device 20 can project a predetermined image as a virtual image onto the windshield 3 by emitting display light. The user can recognize the virtual image when the display light is reflected by the windshield 3. The image generation device 20 is, for example, a liquid crystal display device having a liquid crystal display or the like.

[0039] As shown in Figure 5A, the image generation device 20 includes a display element 21, a light-emitting module 22, an illumination lens 23, an optical mirror 24, and a case 25.

[0040] The display element 21 is a liquid crystal display element 21 such as a liquid crystal panel. The display surface 21a of the display element 21 emits light when light from the light-emitting module 22 is shone on it from the back side. The display element 21 emits display light from the display surface 21a that shows an image including numbers, characters, and figures in response to control instructions from the ECU (Electronic Control Unit) mounted on the vehicle 2. Specifically, the display element 21 can display an image by being driven by AC power obtained from the power supply unit inside the vehicle 2. As a result, the display element 21 can emit display light from the display surface 21a that becomes the projected image on the windshield 3.

[0041] The light-emitting module 22 has a plurality of light sources 22a arranged along a predetermined direction and a substrate on which the plurality of light sources 22a are mounted. The plurality of light sources 22a are held so as to irradiate light toward the optical mirror 24 via the illumination lens 23. Each of the plurality of light sources 22a is composed of, for example, a light-emitting diode. For example, each of the plurality of light sources 22a is driven by DC power obtained from a power supply unit in the vehicle 2.

[0042] The illumination lens 23 is located in the direction of light emission from the light source 22a and is positioned in the optical path between the light source 22a and the optical mirror 24. The illumination lens 23 can direct the light emitted from the light source 22a toward the optical mirror 24.

[0043] The illumination lens 23 corresponds to the multiple light sources 22a. In other words, the illumination lens 23 has a long shape that extends along the direction in which the multiple light sources 22a are arranged. The illumination lens 23 also extends along a predetermined direction, similar to the direction in which the multiple light sources 22a are arranged. This predetermined direction may be, for example, substantially parallel to the left-right direction of the vehicle 2, or it may be non-parallel.

[0044] The illumination lens 23, which extends in a predetermined direction corresponding to the left-right direction of the display element 21, has a symmetrical shape on one side and the other side in that predetermined direction. Due to this relationship between the illumination lens 23 and the multiple light sources 22a, the illumination lens 23 can collect the light emitted by each of the multiple light sources 22a and project light toward the optical mirror 24 with reduced brightness unevenness.

[0045] The optical mirror 24 is positioned in the case 25 so as to face each other, while being separated from the light source 22a and the illumination lens 23 by a predetermined distance. Specifically, the optical mirror 24 is positioned in the direction of emission of light from the light source 22a emitted from the illumination lens 23, and on the optical path between the light source 22a, the illumination lens 23, and the display element 21. In other words, the optical mirror 24 is positioned opposite the display element 21 and opposite the illumination lens 23. Therefore, the optical mirror 24 can reflect the light emitted from the light source 22a, which has been focused by the illumination lens 23, toward the display element 21.

[0046] The optical mirror 24 is a planar mirror or a concave mirror having a free-form surface. In this embodiment, the optical mirror 24 is a rectangular mirror that is elongated in the left-right direction of the vehicle 2. The shape of the optical mirror 24 is not particularly limited and may be polygonal or circular.

[0047] In this way, the light emitted from the light source 22a is focused by the illumination lens 23 and incident on the optical mirror 24. The optical mirror 24 reflects the incident light toward the display element 21. As a result, the light emitted from the light source 22a is incident on the display element 21. Since the light from the light source 22a passes through the display element 21, the display element 21 can emit display light that shows the displayed image.

[0048] As shown in Figure 4A, the case 25 is also formed as a resin injection molded body by the case mold of the injection molding machine, similar to the first housing 11 and the second housing 12, respectively.

[0049] The case 25 houses the optical mirror 24 and the display element 21. The case 25 can accommodate the display element 21, the light-emitting module 22, the illumination lens 23, and the optical mirror 24. The case 25 is connected to the first housing 11 and the second housing 12 by fastening parts 91.

[0050] Specifically, the case 25 has a housing section 25a that houses the display element 21, the light-emitting module 22, the illumination lens 23, and the optical mirror 24. A flange-shaped connecting piece 25b is formed on the outer circumference of the housing section 25a. The connecting piece 25b is fastened to the first mounting section 11a of the first housing 11 and the second mounting section 12a of the second housing 12 by fastening sections 91. The connecting piece 25b has an insertion hole 12a1 of the second mounting section 12a and an insertion hole 25b2 corresponding to the fastening hole 11a1 of the first mounting section 11a.

[0051] The connecting piece 25b has a mounting surface 25b1 for attachment to the housing 10. The mounting surface 25b1 is substantially parallel to the parting line surface P. The mounting surface 25b1 is the downward side surface of the connecting piece 25b and is substantially parallel to the left-right direction of the vehicle 2. The mounting surface 25b1 is in close contact with the upper surface of the first mounting portion 11a of the first housing 11.

[0052] When case 25 is attached to the first housing 11 and the second housing 12, the direction in which the insertion hole 12a1 of the second mounting portion 12a in the second housing 12, the insertion hole 25b2 of the connecting piece 25b, and the fastening hole 11a1 of the first mounting portion 11a in the first housing 11 are aligned is substantially perpendicular to the parting line surface P, and substantially parallel in the vertical direction. The direction in which the fastening portion 91 is inserted is substantially parallel to the vertical direction.

[0053] Here, as shown in Figure 6A, the display surface 21a of the display element 21 is defined such that the direction along the display surface 21a of the display element 21 corresponding to the left-right direction of the virtual image is defined as the X-axis direction, the direction along the display surface 21a of the display element 21 corresponding to the up-down direction of the virtual image is defined as the Y-axis direction, and the direction perpendicular to the display surface 21a is defined as the Z-axis direction. Specifically, the left direction of the virtual image may be defined as the positive X-axis direction, the right direction of the virtual image as the negative X-axis direction, the up direction of the virtual image as the positive Y-axis direction, the down direction of the virtual image as the negative Y-axis direction, the front direction of the virtual image as the positive Z-axis direction, and the back direction of the virtual image as the negative Z-axis direction.

[0054] In this case, the display element 21 can be mounted on the housing 10 via the case 25 such that the parting line surface P and the X-axis direction are substantially parallel.

[0055] In this case, as shown in Figure 6B, when the light ray directed from the display element 21 toward the center of the virtual image is defined as the central ray, the direction of the central ray emitted from the display element 21 is different from the direction of the normal to the display surface 21a of the display element 21.

[0056] If the Y-axis direction is perpendicular to the X-axis direction and along the display surface 21a corresponding to the vertical direction of the virtual image, then the X-axis component of the display light emitted from the display element 21 is 1 / 20 or less of the other components of the display light emitted from the display element 21.

[0057] In such a head-up display 1, when mounted on a vehicle 2, the image generation device 20 can be made common for both the left and right sides. For example, Figure 7(a) shows the image displayed on the display surface 21a when the head-up display 1 equipped with an image generation device 20 having a display element 21 is placed on the left side of the vehicle 2 (for left-hand drive vehicles). Figure 7(d) shows the image displayed on the display surface 21a when the head-up display 1 equipped with an image generation device 20 having a display element 21 is placed on the right side of the vehicle 2 (for right-hand drive vehicles). Figures 7(b) and (c) show the images displayed on the display surface when the head-up display, using the prior art method to make the image generation device common for both sides, is placed on the left side of the vehicle (for left-hand drive vehicles). Figures 7(e) and (f) show the images displayed on the display surface when the head-up display, using the prior art method to make the image generation device common for both sides, is placed on the right side of the vehicle (for right-hand drive vehicles).

[0058] In Figures 7(a) and 7(d) of this embodiment, the image is positioned within the frame of the display surface 21a. In this case, the virtual image is projected onto the windshield 3 without any loss of detail.

[0059] However, when using a conventional image generation device in a head-up display to unify the image generation device for both the left and right sides, the direction along the parting line plane and the display surface of the display element is not parallel to the X-axis direction. As a result, in Figures 7(b), (c), (e), and (f), display defects occur, as indicated by the dashed-dot circles, and a portion of the virtual image is projected onto the windshield. In this case, the user may not be able to correctly recognize the necessary information or may perceive the virtual image as unnatural. For this reason, conventional image generation devices cannot be unified for both the left and right sides.

[0060] The above description concerns the head-up display 1 when the first reflective mirror 31 is installed, but the head-up display 1 of this embodiment is not limited to this.

[0061] Specifically, as shown in Figure 8(a), the head-up display 1 may further have a second reflective mirror 32. In other words, one or more reflective mirrors 30 may include a second reflective mirror 32 in addition to the first reflective mirror 31. That is, the housing may also be equipped with a second reflective mirror 32. The second reflective mirror 32 may be a planar mirror. Furthermore, the light-reflecting surface of the second reflective mirror 32 may be a curved surface including a free-form surface.

[0062] In this case, the image generation device 20 is positioned below the first reflective mirror 31 and the second reflective mirror 32, and forward of the vehicle 2 compared to the second reflective mirror 32. The first reflective mirror 31 and the second reflective mirror 32 are arranged in the housing 10 so as to face each other at a predetermined distance apart. The first reflective mirror 31 is positioned on the front side of the housing 10 of the vehicle 2 so as to face the display surface 21a of the image generation device 20 and the second reflective mirror 32, which are positioned on the front side of the housing 10 of the vehicle 2. The second reflective mirror 32 is located behind the vehicle 2 compared to the first reflective mirror 31, and is positioned parallel to the first reflective mirror 31 along the front-to-rear direction of the vehicle 2. As a result, the second reflective mirror 32 reflects the display light emitted by the image generation device 20 toward the first reflective mirror 31. The first reflective mirror 31 also reflects the display light reflected by the second reflective mirror 32 toward the dust cover 40 through an opening.

[0063] Furthermore, although the image generation device 20 having the display element 21 of Figure 5A is positioned below the first reflective mirror 31 and the second reflective mirror 32 as described above, this embodiment is not limited to this. As shown in Figure 8(b), the image generation device 20 having the display element 21 of Figure 5A may also be positioned above the first reflective mirror 31 and the second reflective mirror 32.

[0064] A display element 21 may be positioned to the left or right of the second reflective mirror 32. Figure 8(c) illustrates the case where the display element 21 is positioned to the left of the second reflective mirror 32.

[0065] In this embodiment, the head-up display 1 can also be a head-up display 1 using a light guide plate 122, as shown in Figures 9 and 10.

[0066] This head-up display 1 includes multiple light sources 22a, a light guide plate 122, a mirror sheet 121, a prism plate 123, a Fresnel lens 124, a heat dissipation glass 125, a liquid crystal panel 126, and a cover member 127.

[0067] The light guide plate 122 has an incident surface 122a into which light emitted from the light source 22a enters, a reflective surface 122b that reflects the light incident from the incident surface 122a, and a light emission surface 122c opposite to the reflective surface 122b. The light guide plate 122 extends along the optical axis of the light emitted from the light source 22a. In this light guide plate 122, the thickness gradually decreases in the direction of the optical axis along the optical axis away from the incident surface 122a. For this reason, the reflective surface 122b is inclined with respect to the incident surface 122a.

[0068] As shown in Figure 10, multiple lens structures 122d are formed on the incident surface 122a of the light guide plate 122. Each of the multiple lens structures 122d corresponds one-to-one with each of the multiple light sources 22a. The multiple lens structures 122d and the multiple light sources 22a are arranged in a predetermined direction corresponding to the left-right direction of the virtual image. The multiple lens structures 122d and the multiple light sources 22a are arranged such that they are symmetrical with respect to the central axis of the light guide plate 122, with respect to the central axis being defined. The central axis is approximately parallel to the optical axis of the light sources 22a. Near the central axis, the distance between two adjacent light sources 22a is set to a, while at the end of the incident surface 122a away from the central axis, the distance between two adjacent light sources 22a is set to a narrower distance b than distance a.

[0069] Note that while Figure 10 illustrates the case where spacing a is narrower than spacing b, the case is not limited to this. For example, spacing a may be narrower than spacing b. In other words, spacing b may be narrower than spacing a along the direction away from the central axis, and spacing b may be wider than spacing a.

[0070] A mirror sheet 121 is superimposed on the reflective surface 122b. The mirror sheet 121 can reflect light toward the light-emitting surface 122c.

[0071] The prism plate 123 is positioned on the light-emitting surface 122c side, opposite to the side where the mirror sheet 121 is located.

[0072] The Fresnel lens 124 is located on the side of the prism plate 123 opposite to the light guide plate 122, and on the side of the prism plate 123.

[0073] The heat dissipation glass 125 is located on the side opposite to the prism plate 123 of the Fresnel lens 124, and is positioned on the side of the Fresnel lens 124.

[0074] The liquid crystal panel 126 is located on the heat dissipation glass 125 side, opposite to the Fresnel lens 124 side of the heat dissipation glass 125.

[0075] The cover member 127 is positioned on the side of the liquid crystal panel 126 opposite to the heat dissipation glass 125 side, and is positioned to overlap with the liquid crystal panel 126.

[0076] In this head-up display 1 using the light guide plate 122, the mirror sheet 121, light guide plate 122, prism plate 123, Fresnel lens 124, heat dissipation glass 125, liquid crystal panel 126, and cover member 127 are arranged so that they overlap in this order.

[0077] When the head-up display 1 of this embodiment is mounted on both the left and right sides of the vehicle 2, the display light is projected onto the windshield 3 symmetrically, as shown in Figure 11. Therefore, the head-up display 1 of this embodiment can project onto the windshield 3 in a state where the virtual image is displayed without any loss.

[0078] <Effects and Effects> Next, the effects and advantages of the head-up display 1 in this embodiment will be described.

[0079] As described above, the head-up display 1 of Technology 1 according to this embodiment is a head-up display 1 that forms a virtual image by projecting display light onto a display medium (windshield 3, etc.), and comprises a housing (housing 10) to which a reflective mirror 30 and a display element 21 are attached. The display element 21 emits display light that becomes a projected image on the display medium by displaying an image, the reflective mirror 30 reflects the display light toward the display medium, and the housing is formed as a resin injection molded body. If the parting line surface P formed by the cavity and core of the housing mold for forming the housing is defined as the X-axis direction, and the direction along the display surface 21a of the display element 21 corresponding to the left-right direction of the virtual image is defined as the X-axis direction, then the housing is mounted such that the parting line surface P and the X-axis direction are substantially parallel.

[0080] According to this, the parting line surface P and the X-axis direction become approximately parallel, making it possible to use the same image generation device 20 for both the left and right sides.

[0081] In this case, when the housing is injection molded from resin, the cavity of the housing mold can be removed from the core in a direction perpendicular to the parting line that occurs during resin injection molding of the housing. In other words, undercuts like those shown in Figure 5B become less likely to occur, and it becomes unnecessary to use a split mold for the cavity, thus suppressing the increase in manufacturing costs of the housing mold.

[0082] Therefore, with this head-up display 1, by making the image generation device 20 common to both the left and right sides, it is possible to suppress the increase in manufacturing costs of the head-up display 1.

[0083] Furthermore, in the head-up display 1 of Technology 2 according to this embodiment, the display element 21 is housed in a case 25, the case 25 is attached to the housing, and the mounting surface 25b1 of the case 25 for attachment to the housing is substantially parallel to the parting line surface P.

[0084] According to this, the display elements 21 can be arranged so that the parting line surface P and the X-axis direction are substantially parallel. Therefore, the image generation device 20 can be made common to both the left and right sides, and the increase in manufacturing costs of the head-up display 1 can be further suppressed.

[0085] Furthermore, in the head-up display 1 of Technology 3 according to this embodiment, when the head-up display 1 is mounted on the vehicle 2, the parting line surface P is substantially parallel to the ground.

[0086] According to this, the display element 21 can be positioned such that its X-axis direction is approximately parallel to the ground. This allows the image generation device 20 to be shared between the left and right sides, and further suppresses the increase in manufacturing costs of the head-up display 1.

[0087] Furthermore, in the head-up display 1 of Technology 4 according to this embodiment, when the light ray directed from the display element 21 toward the center of the virtual image is defined as the central light ray, the direction of the central light ray emitted from the display element 21 is different from the normal direction of the display surface 21a of the display element 21.

[0088] According to this, by making the direction of the central ray of the display light and the normal direction of the display surface 21a different, the display light is reflected at an appropriate angle through the reflective mirror onto the projection surface of the windshield 3. In other words, because the display light can be properly reflected by the reflective mirror, a decrease in the efficiency of light utilization can be suppressed. As a result, the user will be able to clearly see the virtual image projected onto the projection surface of the windshield 3, and it is expected that visibility and clarity will be improved.

[0089] Furthermore, because the display light does not concentrate in a specific area but is more easily distributed evenly across the entire projection surface of the windshield 3, brightness unevenness of the virtual image projected onto the windshield 3 can be suppressed. As a result, the display appears more uniform and brighter.

[0090] Furthermore, in the head-up display 1 of Technology 5 according to this embodiment, if the direction perpendicular to the X-axis direction and along the display surface 21a corresponding to the vertical direction of the virtual image is defined as the Y-axis direction, and the direction perpendicular to the display surface 21a is defined as the Z-axis direction, then the X-axis component of the display light emitted from the display element 21 is 1 / 20 or less of the other components of the display light emitted from the display element 21.

[0091] This allows components other than those in the X-axis direction to be minimized, making it less likely for brightness unevenness to occur in the left-right direction of the virtual image projected onto the windshield 3. As a result, this head-up display 1 can display a visually stable virtual image for the user.

[0092] Furthermore, in the head-up display 1 of Technology 6 according to this embodiment, the case 25 is equipped with an illumination lens 23 that extends in a predetermined direction corresponding to the left-right direction of the display element 21, and the illumination lens 23 has a symmetrical shape on one side and the other side in the predetermined direction.

[0093] This allows the left-right symmetry of the virtual image to be matched with the symmetry of the illumination lens 23 in a predetermined direction. In this case, the display light can be projected so that the brightness is symmetrical on both sides with respect to the projection surface of the windshield 3. Since brightness unevenness in the left-right direction of the virtual image projected onto the windshield 3 can be suppressed, the user will be able to clearly see the virtual image, and it is expected that visibility and clarity will be improved.

[0094] Furthermore, in the head-up display 1 of Technology 7 according to this embodiment, the reflective mirror is positioned opposite the display element 21.

[0095] According to this, by using one reflective mirror and one display element 21, the complexity of the structure and system of the head-up display 1 can be suppressed, and complex optical designs can be avoided. As a result, it is expected that the overall structure of the head-up display 1 can be made smaller, and that manufacturing costs can be reduced and maintenance can be simplified.

[0096] Furthermore, in the head-up display 1 of Technology 8 according to this embodiment, the housing is further equipped with a folding mirror (second reflective mirror 32), and the folding mirror (second reflective mirror 32) reflects the display light emitted by the display element 21 toward the reflective mirror.

[0097] According to this, by mounting the first reflective mirror 31 and the second reflective mirror 32 on the head-up display 1, the display light can be adjusted so that it is projected onto the eye box at the optimal angle. In other words, by using the first reflective mirror 31 and the second reflective mirror 32, the reflection path of the display light can be finely adjusted, which is expected to ensure optimal visibility for the user. In particular, because the projection position in the field of view can be appropriately adjusted, the user will be able to comfortably view the virtual image even while driving.

[0098] Furthermore, by using the first reflective mirror 31 and the second reflective mirror 32, flexibility can be provided in the installation position of the display element 21 and the reflective mirror 30.

[0099] Furthermore, in the head-up display 1 of Technology 9 according to this embodiment, a display element 21 is arranged in the upper or lower direction of the folding mirror (second reflective mirror 32).

[0100] According to this, by arranging the display element 21 above or below the second reflective mirror 32, the head-up display 1 can be efficiently integrated into the limited space inside the vehicle. In particular, since the second reflective mirror 32 can be positioned to match the design of the instrument panel or dashboard, the display system can be made compact while minimizing interference with other components inside the vehicle 2.

[0101] Furthermore, in the head-up display 1 of the technology 10 according to this embodiment, a display element 21 is arranged to the left or right of the folding mirror (second reflective mirror 32).

[0102] According to this, by positioning the display element 21 to the left or right of the second reflective mirror 32, the head-up display 1 can be efficiently integrated into the limited space inside the vehicle. In particular, since the second reflective mirror 32 can be positioned to match the design of the instrument panel or dashboard, the display system can be made compact while minimizing interference with other components inside the vehicle 2.

[0103] Furthermore, in the head-up display 1 of the technology 11 according to this embodiment, the folding mirror (second reflective mirror 32) is a flat mirror.

[0104] According to this, since the angle of reflection is equal to the angle of incidence, the path of light can be accurately predicted, making optical design easier.

[0105] Furthermore, because of its flat shape, a plane mirror is less prone to distortion and warping of reflected light. As a result, users can clearly perceive virtual images, which is expected to improve visibility and clarity.

[0106] Furthermore, in the head-up display 1 of technology 12 according to this embodiment, the light-reflecting surface of the folding mirror (second reflective mirror 32) is a curved surface that includes a free-form surface.

[0107] According to this, because the light-reflecting surface is a free-form surface, the path of the reflected display light can be controlled more flexibly. Furthermore, by adjusting the curvature of the light-reflecting surface, the display light can be guided to a specific angle and direction, which is expected to enable the realization of a more optimal display position for the virtual image and improve visibility.

[0108] (Other variations) The head-up display relating to this disclosure has been described above based on the embodiments described above, but this disclosure is not limited to these embodiments. Various modifications to the embodiments that a person skilled in the art can conceive of may also be included in the scope of this disclosure, as long as they do not deviate from the spirit of this disclosure.

[0109] Furthermore, this disclosure also includes forms obtained by applying various modifications to the above embodiments that a person skilled in the art could conceive, and forms realized by arbitrarily combining the components and functions of the embodiments without departing from the spirit of this disclosure. [Industrial applicability]

[0110] This disclosure is applicable to head-up displays installed in vehicles. [Explanation of symbols]

[0111] 1. Head-up display 2 vehicles 3. Windshield (Display medium) 10 Housing (enclosure) 21 Display elements 21a Display surface 23 Illumination Lens 25 cases 25b1 Mounting surface 30 Reflective Mirrors 31. First Reflecting Mirror (Reflecting Mirror) 32. Second Reflecting Mirror (Reflective Mirror) P Parting line surface

Claims

1. A head-up display that forms a virtual image by projecting display light onto a display medium, It comprises a housing on which a reflective mirror and a display element are mounted, The display element emits the display light that becomes the projected image on the display medium by displaying an image. The reflective mirror reflects the display light toward the display medium, The housing is formed as a resin injection molded body, If the X-axis direction is defined as the direction along the parting line surface formed by the cavity and core of the housing mold for forming the housing and the display surface of the display element corresponding to the left-right direction of the virtual image, then the housing is mounted such that the parting line surface and the X-axis direction are substantially parallel. Head-up display.

2. The display element is housed in a case, The case is attached to the aforementioned housing. The mounting surface of the case for attachment to the housing is substantially parallel to the parting line surface. The head-up display according to claim 1.

3. When the head-up display is mounted on a vehicle, the parting line surface is substantially parallel to the ground. The head-up display according to claim 1 or 2.

4. When the light ray emanating from the display element toward the center of the virtual image is defined as the central ray, the direction of the central ray emitted from the display element is different from the normal direction of the display surface of the display element. The head-up display according to claim 1 or 2.

5. If the direction perpendicular to the X-axis direction and along the display surface corresponding to the vertical direction of the virtual image is defined as the Y-axis direction, and the direction perpendicular to the display surface is defined as the Z-axis direction, The X-axis component of the display light emitted from the display element is 1 / 20 or less of the components of the display light emitted from the display element in directions other than the X-axis. The head-up display according to claim 1 or 2.

6. The case is equipped with an illumination lens that extends in a predetermined direction corresponding to the left-right direction of the display element. The illumination lens has a shape that is symmetrical on one side and the other side in the predetermined direction. The head-up display according to claim 2.

7. The reflective mirror is positioned opposite the display element. The head-up display according to claim 1 or 2.

8. The aforementioned housing is further equipped with a folding mirror. The aforementioned folding mirror reflects the display light emitted by the display element toward the reflective mirror. The head-up display according to claim 2.

9. The display element is positioned above or below the aforementioned folding mirror. The head-up display according to claim 8.

10. The display element is positioned to the left or right of the aforementioned folding mirror. The head-up display according to claim 8.

11. The aforementioned folding mirror is a plane mirror. The head-up display according to claim 8.

12. The light-reflecting surface of the aforementioned folding mirror is a curved surface that includes a free-form surface. The head-up display according to claim 8.

Images