Display device

Abstract

To provide a display device which can highly accurately adjust the display position by preventing wobbling in a connection part between a reflector and a tilting member tilting the reflector.SOLUTION: A display device comprises: a reflector 5 which projects image light of an image from an image display unit displaying an image to a windshield to allow a virtual image of the image to be visually recognized; and a tilting member 7 which tilts the reflector 5 with a rotational shaft 51 as a fulcrum. The rotational shaft 51 includes a connection shaft part 53 which is formed with an elastic contact surface in the direction intersecting the radial direction in a portion thereof in the circumferential direction and which is connected to the tilting member 7 by being inserted to a connection hole 71 provided in the tilting member 7. The tilting member 7 holds an elastic member 9 which elastically contacts the elastic contact surface 54 and biases the connection shaft part 53 in the radial direction with respect to the inner surface of the connection hole 71.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a display device provided in a vehicle such as an automobile, and more particularly to a display device suitable for use as a head-up display. [Background technology]

[0002] A head up display (hereinafter referred to as a HUD device) that displays a required image to the vehicle occupants has been proposed as a display device for an automobile. For example, in Patent Document 1, this HUD device is configured to project an image displayed on an image display element such as a liquid crystal display (LCD) onto the windshield (e.g., the front glass) of the automobile using an optical system, and to allow the occupants to visually recognize a virtual image (hereinafter also referred to as a display image) formed by image light reflected by the windshield.

[0003] Such HUD devices usually have a concave mirror as part of the optical system that projects the image, and a device is provided to adjust the position where the image light reflected by the concave mirror is projected onto the windshield so that passengers at different eye heights can view a suitable displayed image. For example, a tilting arm is connected to a rotation shaft provided on the concave mirror, and the angle of the reflecting surface of the concave mirror is adjusted by tilting this tilting arm with an actuator, thereby adjusting the reflection direction of the image light.

[0004] In this HUD device, if there is a dimensional error or assembly error in the connection between the rotation axis and the tilt arm, a rattle will occur between the tilt angle of the tilt arm and the concave mirror, making it impossible to adjust the angle position of the concave mirror with high precision. Also, the angle of the concave mirror will change due to vibrations that occur when the car is traveling, causing the image position of the image to fluctuate, resulting in a decrease in display quality.

[0005] Technologies for preventing rattle at the connection of a rotating shaft include those described in Patent Documents 2 and 3. Both Patent Documents 2 and 3 have a structure in which an elastic member is elastically inserted between a rotating shaft with a spline structure and a shaft hole into which the rotating shaft is fitted, and the elastic force of this elastic member is used to press the rotating shaft against one of the inner surfaces of the shaft hole to prevent rattle. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP2018-173589A [Patent Document 2] Japanese Patent Application Publication No. 8-49726 [Patent Document 3] Japanese Utility Model Application Publication No. 60-185725 Summary of the Invention [Problem to be solved by the invention]

[0007] In the HUD device, it is required to configure the optical system compactly in order to minimize the space required for mounting the device in the vehicle. For example, it is possible to shorten the rotation axis of the concave mirror and minimize the thickness of the arm to which the rotation axis is connected. However, if this is done, the axial dimension of the rotation axis and the shaft hole constituting the connecting part becomes extremely short, and it becomes difficult to prevent the rattle of the rotation axis and the shaft hole by inserting an elastic member into the gap between the rotation axis and the shaft hole as in Patent Documents 2 and 3. In other words, if the axial dimension of the rotation axis and the shaft hole becomes short, it is difficult to ensure sufficient elastic force even if a linear spring is inserted as in Patent Document 2, because the spring length becomes short. In addition, it is difficult to insert a coil spring as in Patent Document 3 into the gap between the rotation axis and the shaft hole, and even if it is inserted, it is difficult to maintain the state stably and continuously.

[0008] Furthermore, because the technology of Patent Documents 2 and 3 is a technology for inserting an elastic member into the gap between the rotating shaft and the shaft hole, the work of monitoring the deterioration state of the elastic member or replacing it when it is damaged becomes extremely cumbersome. In particular, in the adjustment mechanism in which the axial dimension of the rotating shaft and the shaft hole is made as small as possible as described above, it is difficult to directly apply the technology of Patent Documents 2 and 3, and it is difficult to realize a small HUD device.

[0009] An object of the present invention is to provide a display device that can adjust the display position with high accuracy by preventing rattling at the connection between a reflecting mirror such as a concave mirror and a tilting member such as a tilting arm. Another object of the present invention is to provide a display device such as a small HUD device. [Means for solving the problem]

[0010] The present invention relates to a display device that includes an image display unit that displays an image and a reflector that projects image light of the displayed image onto a windshield of a vehicle, and that allows a virtual image of the image to be viewed by the light reflected by the windshield. The display device includes a tilting unit for tilting the reflector around its rotation axis as a fulcrum, and the tilting unit includes a tilting member that is connected to the rotation axis and tilts the reflector integrally when tilted. The rotation axis has an elastic contact surface formed in a part of its circumferential direction in a direction intersecting the radial direction, and has a connecting shaft portion that is inserted into a connecting hole provided in the tilting member and connected to the tilting member. The tilting member also holds an elastic member that is elastically contacted with the elastic contact surface and biases the connecting shaft portion in the radial direction against the inner surface of the connecting hole.

[0011] The elastic member in the present invention is configured such that a fitting portion that is fitted and held in a retaining hole provided in the tilting member and an elastic contact portion that is elastically contacted with an elastic contact surface of the connecting shaft portion and biases the connecting shaft portion in a radial direction are integrally formed. The elastic member is configured to be detachable from the tilting member when the connecting shaft portion is inserted into the connecting hole.

[0012] In a preferred embodiment of the present invention, the reflector is a concave mirror that is tilted so that the angle of its reflecting surface is changed relative to the windshield, for example, in a head-up display of an automobile, the windshield being the front glass of the automobile. Effect of the Invention

[0013] According to the present invention, the connecting shaft portion having the elastic contact surface is inserted into the connecting hole provided in the tilting member, and is biased radially against the inner surface of the connecting hole by the elastic member elastically contacting the elastic contact surface, so that rattling between the reflecting mirror and the tilting member can be prevented. Fitting part By configuring the display device so that the display device is held by the tilting member at the tilting member and the elastic contact portion is elastically contacted with the elastic contact surface of the connecting shaft portion, the length of the connecting shaft portion can be shortened, thereby making it possible to configure the display device in a compact size. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a conceptual configuration diagram of a HUD device to which the present invention is applied. [Diagram 2] FIG. 1 is a schematic perspective view of a HUD device according to a first embodiment. [Diagram 3] FIG. 4 is a perspective view of a connection portion between a concave mirror and a tilting arm in the first embodiment. [Figure 4] FIG. 4 is a partially exploded perspective view of a connection portion between the concave mirror and the tilting arm in the first embodiment. [Diagram 5] FIG. 2A is a side view of a connecting portion of a tilting arm of the first embodiment, and FIG. [Figure 6] FIG. 11 is a schematic perspective view of a HUD device according to a second embodiment. [Figure 7] FIG. 11 is a perspective view of a connection portion between a concave mirror and a sector gear arm in the second embodiment. [Figure 8] FIG. 11 is a partially exploded perspective view of a connection portion between a concave mirror and a sector gear arm in the second embodiment. [Figure 9] FIG. 11A is a side view of a connecting portion of a tilting arm of the second embodiment, and FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram of a HUD device applied to an automobile, as viewed from the left side of the automobile. A HUD device 1 is disposed in a dashboard DB of the automobile, and image light L emitted from the HUD device 1 is projected onto a front glass (referred to as a windshield) WS of the automobile through an upper opening Ho of the dashboard. The projected image light L is reflected by the windshield WS and directed toward an occupant M, such as a driver of the automobile. When the image light L enters the eyes of the occupant M, the occupant M can visually recognize a virtual image I due to the image light at a position in front of the automobile through the windshield WS, and the image is displayed.

[0016] (Embodiment 1) Fig. 2 is a schematic perspective view of the HUD device 1 of the embodiment 1. The HUD device 1 is assembled to a frame 10 as a device fixing portion, and includes an image display unit 2 and an optical system 3 that projects an image displayed on the image display unit 2 onto the windshield WS shown in Fig. 1. The image display unit 2 is configured to display a desired image and emit the image light, and is configured, for example, by a liquid crystal display device.

[0017] The optical system 3 has two reflecting mirrors: a convex mirror 4 that reflects the image light of the image displayed on the image display unit 2, and a concave mirror 5 that further reflects the light reflected by the convex mirror 4 and projects it onto the windshield WS shown in Fig. 1. The convex mirror 4 is provided to improve aberrations in the concave mirror 5 and to substantially extend the focal length of the concave mirror 5, but the convex mirror 4 is not necessarily required.

[0018] The concave mirror 5 is configured with a spherical surface or a free-form surface with a curvature that results in a required focal length. The HUD device 1 is configured so that the image displayed on the image display unit 2 is located within the focal length of the concave mirror 5. The light reflected by the concave mirror 5 is reflected by the windshield WS as shown in Fig. 1 and enters the eye of the occupant M, so that the occupant M can visually recognize a virtual image I in front of the windshield WS.

[0019] The HUD device 1 is provided with a tilting unit 6 for tilting the concave mirror 5. By adjusting the angle of the concave mirror 5 with this tilting unit 6, as shown by the dashed line in Fig. 1, the direction of the light reflected by the concave mirror 5 is changed, and the position and direction of the light projected onto the windshield WS are changed. This changes the direction of the light entering the eyes of the occupant M, as shown by the chain line, and changes the position and direction of the virtual image I that is viewed.

[0020] The tilting section 6 includes a tilting arm 7 having one end connected to the concave mirror 5, and an actuator 8 that tilts the other end of the tilting arm 7 relative to the one end. The tilting arm 7 constitutes the tilting member of the present invention, and is formed in a long and narrow plate shape here. One end of the tilting arm 7 is integrally connected to the concave mirror 5, and the other end is engaged with the actuator 8.

[0021] The concave mirror 5 has a pair of rotation shafts 51, 52 protruding outward from the left and right side edges, respectively. The pair of rotation shafts 51, 52 are rotatably supported by a frame 10 provided in the HUD device 1, and the concave mirror 5 can rotate, i.e., tilt, at a required angle in the vertical direction relative to the frame 10 with the rotation shafts 51, 52 as fulcrums. The concave mirror 5 is connected to the tilting arm 7 at one rotation shaft 51 of the pair of rotation shafts 51, 52.

[0022] Fig. 3 is a perspective view of the joint between the concave mirror 5 and the tilt arm 7, and Fig. 4 is a partially exploded perspective view thereof. The portion where the pair of rotation shafts 51, 52 of the concave mirror 5 are supported by the frame 10 may be constituted by a plain bearing or a ball bearing, but in this case, in order to simplify the structure, it is constituted as a plain bearing in which the rotation shafts 51, 52 are inserted into a bearing hole 11 opened in the frame 10.

[0023] The rotating shaft 51 connected to the concave mirror 5 has a portion protruding from the position where it is supported by the frame 10, which constitutes a connecting shaft portion 53 with the tilting arm 7. This connecting shaft portion 53 is formed to have a non-circular shape when viewed from the axial direction. Here, a portion of the circumferential direction of the cylindrical rotating shaft 51 is removed to form a semicircular shape having a flat surface 54 in a direction intersecting with the radial direction. This flat surface 54 constitutes an elastic contact surface in the present invention, and is hereinafter referred to as the elastic contact surface 54.

[0024] Meanwhile, at one end of the tilting arm 7, a semicircular connecting hole 71 corresponding to the semicircular shape of the connecting shaft portion 53 is opened in the plate thickness direction. Then, by inserting the connecting shaft portion 53 into this connecting hole 71, the connecting hole 71 and the connecting shaft portion 53 are fitted together, and the tilting arm 7 is integrated with the concave mirror 5 in its tilting direction. Here, the length dimension of the connecting shaft portion 53 and the thickness dimension of the tilting arm 7 are approximately the same, but by making these dimensions as short as possible, the dimensions of the tilting portion 6, particularly the dimension in the width direction of the concave mirror 5 (the axial direction of the rotation shafts 51, 52) can be shortened, thereby making the HUD device 1 more compact.

[0025] Furthermore, one end of the tilting arm 7 has a rectangular spring retaining hole 72 opened in the thickness direction at a position adjacent to the connecting hole 71, into which a plate spring 9 configured as the elastic member of the present invention is fitted and supported. This plate spring 9 is configured by bending a leaf spring material such as an elastic metal plate, for example a SUS plate, in the thickness direction, and has a fitting portion 91 bent into an approximately U-shape and a semicircular arc-shaped elastic contact portion 92.

[0026] Fig. 5(a) is a side view of the connection part, and Fig. 5(b) is a cross-sectional view taken along line b1-b1 thereof. By fitting the fitting part 91 of the plate spring 9 into the spring holding hole 72 in a thick-fitting state, the plate spring 9 is supported by the tilting arm 7 by the elastic restoring force of the fitting part 91. Also, the elastic contact part 92 is elastically contacted in the radial direction with the elastic contact surface 54 of the connecting shaft part 53 by its own elastic force. By the plate spring 9 being elastically contacted with the elastic contact surface 54, the connecting shaft part 53 is biased in the radial direction inside the connecting hole 71. And, since the circumferential surface of the connecting shaft part 53 abuts against the inner circumferential surface of the connecting hole 71, the rotating shaft 51 and the tilting arm 7, in other words, the concave mirror 5 and the tilting arm 7 are integrated in the tilting direction of both.

[0027] As shown in Fig. 2, the actuator 8 is supported by the frame 10, and although illustration of its internal structure is omitted, it includes a ring nut that is rotated at a reduced speed by the rotation of the pulse motor, and a screw rod 81 screwed into the ring nut. The tip of the screw rod 81 is engaged with the other end of the tilting arm 7 in a state in which it can move freely. For example, it is engaged via a ball joint 70. When the ring nut of the actuator 8 is rotated by the reciprocating rotation of the pulse motor, the screw rod 81 screwed thereto is moved reciprocally in the rod axial direction, and the other end of the tilting arm 7 engaged with the screw rod 81 is moved vertically with one end as a fulcrum.

[0028] In the HUD device 1 equipped with the tilting unit 6 described above, as described with reference to Fig. 1, the image light of the image displayed on the image display unit 2 is reflected successively by the convex mirror 4 and the concave mirror 5 of the optical system 3, and projected onto the windshield WS of the automobile. The projected image light L is reflected by the windshield WS and directed toward an occupant M of the automobile, who visually recognizes an image (virtual image) I at a position in front of the automobile through the windshield WS.

[0029] At this time, in the HUD device 1, the actuator 8 of the tilting section 6 is controlled to change and control the axial position of the screw rod 81, and the other end of the tilting arm 7 engaged therewith is moved vertically with one end as a fulcrum, thereby adjusting the tilt angle of the tilting arm 7. This tilting of the tilting arm 7 causes the connected concave mirror 5 to be tilted integrally, and its angle is adjusted. By adjusting the angle of the concave mirror 5 in this manner, the position and direction of the image light projected onto the windshield WS shown in Fig. 1 are changed, and adjustment is made so that the image (virtual image I) can be viewed appropriately for each of the occupants M with different line of sight positions.

[0030] During this angle adjustment, even if a gap occurs between the connected connecting shaft 53 and the connecting hole 71 due to dimensional errors, assembly errors, etc., the elastic contact surface 54 of the connecting shaft 53 is biased radially by the plate spring 9 and its circumferential surface is pressed against the circumferential surface of the connecting hole 71, preventing rattling from occurring between the connecting shaft 53 and the connecting hole 71. Therefore, the tilting motion of the tilting arm 7 is transmitted directly to the connecting shaft 53, i.e., the rotation shaft 51, and the concave mirror is tilted, making it possible to adjust the angle of the concave mirror 5 with high precision and enabling an appropriate display regardless of differences in eye height of the occupant.

[0031] In this state, if vibrations caused by the car traveling are transmitted to HUD device 1, there is a risk that the vibrations will cause the angle of concave mirror 5 to fluctuate. However, since connecting shaft 53 of concave mirror 5 is connected to tilting arm 7 by plate spring 9 inside connecting hole 71, and tilting of tilting arm 7 is restricted by actuator 8, the angle of concave mirror 5 is prevented from fluctuating, and fluctuations in the displayed image while the car is traveling are prevented.

[0032] In this way, the plate spring 9 radially biases the elastic contact surface 54 provided on the connecting shaft portion 53 at the connecting portion, thereby maintaining the close contact between the connecting shaft portion 53 and the connecting hole 71 and preventing rattling between them. Also, the plate spring 9 can be formed to any size regardless of the plate thickness of the tilting arm 7 or the axial length of the connecting shaft portion 53. Therefore, compared to the techniques of Patent Documents 2 and 3 in which a spring material is inserted between the shaft and the shaft hole, there is no restriction on the size or shape of the spring material, and it is possible to ensure sufficient elasticity to prevent rattling.

[0033] In addition, because the plate spring 9 is exposed, it can be attached and detached even when the connecting shaft portion 53 is inserted into the connecting hole 71, and the assembly work of the plate spring 9 is easy. Therefore, it is easy to monitor the condition of the plate spring 9 or to replace it when it is damaged.

[0034] Furthermore, since the plate spring 9 is held with its fitting portion 91 fitted in the spring holding hole 72 provided in the tilting arm 7, there is a high degree of freedom in designing the fitting portion 91, and a plate spring 9 with high holding force and capable of stable holding can be obtained. In addition, since the elastic contact portion 92 can also be designed without being affected by the shape and dimensions of the fitting portion 91, the biasing force against the flat surface 54 of the connecting shaft portion 53 can be set as desired.

[0035] It is possible to mold the tilting arm 7 and the concave mirror 5 as one unit in order to prevent rattling between them, but in that case the materials for the concave mirror 5 and the tilting arm 7 would be limited to materials that can be molded as one unit, such as resin, which would be difficult to realize due to problems with mechanical strength and durability due to deterioration over time, etc. It is also possible to integrally connect the tilting arm 7 and the concave mirror 5 with a fixing means such as a screw, but this would make the assembly process more troublesome compared to the configuration in this embodiment in which assembly can be completed simply by fitting the connecting shaft into the connecting hole and attaching the plate spring.

[0036] (Embodiment 2) 6 is a perspective view of a tilting section 6A of a HUD device 1A of the second embodiment. Parts equivalent to those of the first embodiment are given the same reference numerals. As in the first embodiment, a pair of rotation shafts 51, 52 protrude from the left and right side edges of the concave mirror 5, and the concave mirror 5 is supported by the frame 10 at these rotation shafts 51, 52, so that the concave mirror 5 can be tilted in the vertical direction. On the other hand, in the tilting section 6A of the second embodiment, a sector gear arm 7A as a tilting member according to the present invention is connected to the concave mirror 5, and the actuator 8A tilts the sector gear arm 7A to adjust the angle of the concave mirror 5. The sector gear arm 7A is connected to the concave mirror 5 at one end, and a sector gear (sector gear) 75 is integrally formed at the other end.

[0037] The actuator 8A is composed of a pulse motor equipped with a reduction gear mechanism, and a small gear 82 provided on the rotating shaft of the actuator 8A is meshed with the sector gear 75 of the sector gear arm 7A. When the pulse motor 8A is driven to rotate the small gear 82, the meshed sector gear 75 is rotated at a small angle, and the sector gear arm 7A is tilted.

[0038] Fig. 7 is a perspective view of the connection between the concave mirror 5 and the sector gear arm 7A, and Fig. 8 is a partially exploded perspective view thereof. Of a pair of rotation shafts 51, 52 protruding from the left and right side edges of the concave mirror 5, one of the rotation shafts 51 is configured with a connection shaft portion 55, to which the sector gear arm 7A is connected.

[0039] In the second embodiment, the connecting shaft portion 55 and the sector gear arm 7A are connected by a spline structure. That is, the connecting shaft portion 55 has a petal-shaped spline structure having five convex portions 56 arranged in the circumferential direction when viewed from the axial direction, and the dimension of the circumferential interval between two predetermined convex portions 56 is made relatively larger than the other intervals, and a flat elastic contact surface 57 is formed in this interval.

[0040] On the other hand, a connecting hole 73 into which the connecting shaft portion 55 is inserted is opened at one end of the sector gear arm 7A. This connecting hole 73 is formed in a spline structure having five recesses 74 corresponding to the cross-sectional shape of the connecting shaft portion 55. Then, by inserting the connecting shaft portion 55 into this connecting hole 73, the connecting hole 73 and the connecting shaft portion 55 are fitted together by the spline structure, and the sector gear arm 7A is integrated with the concave mirror 5 in its tilting direction.

[0041] Also, in the sector gear arm 7A, a rectangular spring holding hole 72 is opened in the thickness direction at a position adjacent to the connecting hole 73, as in the first embodiment, and a plate spring 9 is fitted and supported in this hole. As in the first embodiment, this plate spring 9 has a fitting portion 91 which is bent into a substantially U-shape by bending a leaf spring material in the thickness direction, and a tongue-shaped elastic contact portion 92. Here, the width dimension of the elastic contact portion 92 is made smaller than that of the fitting portion 91 in accordance with the dimension of the elastic contact surface 57.

[0042] Fig. 9(a) is a side view of the connecting portion, and Fig. 9(b) is a cross-sectional view taken along line b2-b2 thereof. The plate spring 9 is held by its own elastic force on the sector gear arm 7A by inserting the fitting portion 91 of the plate spring 9 thickly into the spring holding hole 72. The elastic contact portion 92 of the plate spring 9 is elastically contacted with the elastic contact surface 57 of the connecting shaft portion 55, and the connecting shaft portion 55 is biased radially inside the connecting hole 73, so that the petal portion of the connecting shaft portion 55 opposite to the elastic contact surface 57 abuts against the inner peripheral surface of the connecting hole 73. Therefore, even if there is a dimensional difference between the connecting shaft portion 55 and the connecting hole 73, rattling caused by the connecting shaft portion 55 moving relatively inside the connecting hole 73 is suppressed or prevented, and the concave mirror 5 and the sector gear arm 7A are integrated in the tilting direction.

[0043] In the second embodiment, when adjusting the angle of the concave mirror 5, the actuator 8A of the tilting portion 6A shown in Fig. 6 is driven and controlled to rotate the small gear 82 and rotate the sector gear 75 meshed therewith by a required angle. This tilts the sector gear arm 7A, tilts the concave mirror 5 connected at one end thereof, and adjusts its angle.

[0044] During this angle adjustment, the connecting shaft portion 55 is biased radially by the plate spring 9 inside the connecting hole 73, so that the portion of the connecting shaft portion 55 opposite the elastic contact surface 57 abuts against the inner surface of the connecting hole 73. Therefore, even if there is a dimensional difference between the connecting shaft portion 55 and the connecting hole 73, rattling between the connecting shaft portion 55 and the connecting hole 73 is suppressed or prevented, and rattling between the concave mirror 5 and the sector gear arm 7A is prevented.

[0045] As a result, the tilting motion of the sector gear arm 7A is directly transmitted to the rotation axis of the concave mirror 5 to tilt the concave mirror 5, making it possible to adjust the angle of the concave mirror 5 with high precision, enabling a suitable display regardless of differences in the eye height of the passenger viewing the image. Furthermore, even if vibrations caused by the vehicle traveling are transmitted to the concave mirror 5, the concave mirror 5 is not tilted, preventing fluctuations in the displayed image while the vehicle is traveling.

[0046] In this embodiment 2, even if the plate thickness of the sector gear arm 7A is reduced to reduce the axial dimension of the connecting shaft portion 55, the plate spring 9 can be formed to any dimension, so that sufficient elastic force to prevent rattling can be secured. Also, as in the first embodiment, the plate spring 9 can be attached and detached even when the connecting shaft portion 55 is inserted into the connecting hole 73, and since the plate spring 9 is exposed, the assembly work of the plate spring 9 is easy, and the monitoring work and replacement work are also easy. Similarly, the degree of freedom in design of the fitting portion of the plate spring 9 is increased, so that the plate spring 9 can be held stably with high holding force, and the degree of freedom in design of the elastic contact portion 92 is also increased, so that the elastic contact force against the elastic contact surface 57 of the connecting shaft portion 55 can be set arbitrarily.

[0047] Furthermore, in the second embodiment, since the elastic contact surface 57 is formed between the protrusions 56 that form the spline structure, when the connecting shaft portion 55 is inserted into the connecting hole 73, the elastic contact surface 57 is positioned inside the connecting hole 73 of the sector gear arm 7A. Therefore, the elastic contact portion 92 of the plate spring 9 is elastically contacted with the elastic contact surface 57 inside the connecting hole 73, i.e., within the plate thickness of the sector gear arm 7A. This makes it possible to further reduce the axial dimension of the connecting shaft portion 55 and at the same time reduce the protruding dimension of the plate spring 9, which is advantageous for further miniaturization of the HUD device 1.

[0048] On the other hand, since the connecting shaft portion 55 and the connecting hole 73 in the second embodiment have a spline structure, the rattle between them is higher than in the first embodiment. That is, in the first embodiment, if a radial dimensional difference occurs between the connecting shaft portion 53 and the connecting hole 71, this dimensional difference directly becomes the rattle dimension. In the second embodiment, the spline structure is used, and the outer circumferential surface of the connecting shaft portion 55 and the inner circumferential surface of the connecting hole 73 are respectively divided in the circumferential direction by a plurality of projections 56 and recesses 74, so that the rattle dimension is also divided and reduced.

[0049] In the present invention, the configuration of the connecting shaft portion 53 and the connecting hole 71 in the first embodiment may be configured similarly to that in the second embodiment, that is, the elastic contact portion 92 of the press spring 9 may be configured to elastically contact an elastic contact surface inside the connecting hole 71. This makes it possible to reduce the axial dimension of the connecting shaft portion 53.

[0050] In the first and second embodiments, an example has been described in which a pair of rotating shafts 51, 52 on both sides of the concave mirror 5 are each supported by bearings. However, if stable support is possible with only one of the rotating shafts, the concave mirror 5 may be supported only by one of the rotating shafts (e.g., rotating shaft 52), and the other rotating shaft (e.g., rotating shaft 51) may not be supported and a connecting shaft portion for connecting a tilting arm or a sector gear arm may be formed on part of it.

[0051] The tilting member of the present invention is not limited to the tilting arm or sector gear arm described in the embodiments, and may be configured as, for example, a gear (rotary gear) rotated by an actuator. Also, the actuator in the present invention may be an actuator of another configuration, such as an electromagnetic actuator, as long as it has the function of tilting the tilting member. [Explanation of symbols]

[0052] 1,1A HUD device 2 Image display section 3 Optical system 4 convex mirror 5 Concave mirror (reflector) 6 Tilt part 7 Tilting arm (tilting member) 7A Sector gear arm (tilting member) 8,8A actuator 9 Plate spring (elastic member) 51,52 Rotation axis 53,55 Connecting shaft part 54,57 Resilient surface 91 Fitting part 92 Ballistic contact part

Claims

1. a tilting part for tilting the reflecting mirror about its rotation axis as a fulcrum, the tilting part including a tilting member connected to the rotation axis and tilting the reflecting mirror integrally when tilted, the rotation axis having an elastic contact surface formed in a part of its circumferential direction in a direction intersecting a radial direction, the connecting shaft part being inserted into a connecting hole provided in the tilting member and connected to the tilting member, the tilting member holding an elastic member that is elastically contacted with the elastic contact surface and biases the connecting shaft part in a radial direction against an inner surface of the connecting hole, the elastic member being a plate spring integrally formed with an engagement part that is fitted and held in a retaining hole provided in the tilting member, and an elastic contact part that is elastically contacted with the elastic contact surface of the connecting shaft part and biases the connecting shaft part in a radial direction.

2. The display device according to claim 1 , wherein the elastic member is detachable from the tilting member when the connecting shaft portion is inserted into the connecting hole.

3. 3. The display device according to claim 1, wherein the connecting shaft portion of the rotating shaft is cylindrical and has the elastic contact surface formed on a portion of its circumference.

4. 3. The display device according to claim 1, wherein the connecting shaft portion of the rotating shaft has a spline structure, and the elastic contact surface is formed on a part of the circumference sandwiched between a plurality of protrusions that constitute the spline.

5. 5. A display device as described in any one of claims 1 to 4, wherein the tilting member is configured as a tilting arm connected at one end to a rotation axis of the reflector and engaged at the other end to an actuator, the other end being tilted in a direction around the axis of the rotation axis of the reflector by the actuator.

6. 6. A display device according to claim 1, wherein said reflecting mirror is a concave mirror, and is tilted so that the angle of its reflecting surface with respect to said windshield is changed.

7. 7. The display device according to claim 6, configured as a head-up display for an automobile, the windshield being a front glass of the automobile.

Images