JP2021156955A - Head-up display - Google Patents

Abstract

To provide a head-up display improved in slidability of a reflection unit.SOLUTION: A head-up display 1 reflects a virtual image V by projecting display light Li on a windshield WS, and includes: a display unit 20 for emitting display light Li; a reflection unit 30 for reflecting the display light Li and capable of adjusting a direction of reflecting the display light Li by rotating about a prescribed rotation axis A; and a sliding bearing 50 having a bearing surface 511 for defining the rotation shaft A. The reflection unit 30 has shafts 33, 34, 35 inserted into the sliding bearing 50. The shafts 33, 34, 35 have sliding surfaces 331, 341, 351 that come into contact with the bearing surface 511 to slide and chipped sections 332, 342, 352 where the sliding surfaces 331, 341, 351 are thinned so as to reduce a contact area with the bearing surface 511.SELECTED DRAWING: Figure 4

Description

The present invention relates to a head-up display.

A conventional head-up display is known to have a configuration as shown in Patent Document 1. The head-up display device (10) shown in Patent Document 1 projects the display light (16) emitted from the display unit (12) onto the windshield (17) by being reflected by the concave mirror (15). The concave mirror (15) is rotated about a rotation axis (34) by the position adjusting means (60).

Japanese Unexamined Patent Publication No. 2016-109974

In the head-up display device (10) shown in Patent Document 1, when the concave mirror (15) rotates, the shaft portion (31, 32) slides on the inner surface of the tubular bearing (41, 42) which is a slide bearing. do. There was room for improvement in the structure of the disclosure regarding this slidability.

Therefore, an object of the present invention is to pay attention to the above-mentioned problems and to provide a head-up display in which the smoothness of rotation of the reflecting portion is improved.

In order to achieve the above object, the head-up display according to the present invention is
A head-up display that projects a virtual image by projecting display light onto a reflective and transmissive member.
A display unit that emits the display light and
A reflecting unit that reflects the display light and can adjust the direction in which the display light is reflected by rotating around a predetermined rotation axis.
A plain bearing having a bearing hole that defines the rotation axis, and
The reflective portion has a shaft that is inserted into the slide bearing.
The shaft
A sliding surface that slides in contact with the slide bearing,
The sliding surface has a chipped portion in which the sliding surface is lightened so as to reduce the contact area with the slide bearing.

In the case of the above-mentioned head-up display, the head-up display has improved smoothness of rotation of the reflecting portion.

The figure which shows the structure of the vehicle C in the 1st Embodiment of this disclosure. The figure which shows the structure of the head-up display in the said embodiment. The figure which shows the structure of the reflection part 30 and the bearing part 40 in the said embodiment. The figure which shows the cross section of the main part of the reflection part 30 and the bearing part 40 in the said embodiment. The figure which shows the structure of the slide bearing 50 in the said embodiment. The figure which shows the structure of the shaft 33 in the said embodiment. The graph which shows the slidability of the shaft 33, 34, 35 of this disclosure. The figure which shows the structure of the shaft 34 in the 1st modification. The figure which shows the structure of the shaft 35 in the 2nd modification.

Hereinafter, the head-up display (HUD) 1 of the present disclosure will be described as an example of an embodiment and a modification mounted on the vehicle C, and will be described in the following order with reference to the accompanying drawings. The directions F, B, L, R, U, and D shown in the drawings correspond to the front, rear, left, right, up, and down directions in the vehicle C, respectively. Further, the left-right direction may be referred to as a direction X, the up-down direction may be referred to as a direction Y, and the front-back direction may be referred to as a direction Z. For ease of explanation, some reference numerals that should be attached to the illustrated members may be omitted.

[First Embodiment]
<About the configuration>
<About shaft shape>
[First modification]
[Second modification]
[Other variants]
[Effect example]

[First Embodiment]
<About the configuration>
As shown in FIGS. 1 and 2, the head-up display 1 can be mounted below the windshield WS provided in the vehicle C.

The HUD1 projects a virtual image V by projecting display light Li representing vehicle information on a windshield WS (reflection / transmission member) having a free curved surface shape that is inclined so that the front end of the vehicle is lowered. The HUD1 emits the indicator light Li diagonally upward in the rear direction of the vehicle. The indicator light Li emitted from the HUD1 is reflected by the windshield WS. A user (for example, a occupant of vehicle C) who visually recognizes the display light Li reflected by the windshield WS from the viewpoint EP can visually recognize the projected virtual image V as a floating display image behind the windshield WS.

The virtual image V includes vehicle information such as speed and engine speed, route guidance displays such as turn-by-turns and maps, and warning displays such as blind spot monitors and speed limit excess warnings for passengers (users and users). Information that needs to be alerted is displayed. This provides a driving environment in which the need for viewpoint movement and eye focal length adjustment is reduced. In addition to the characters and icons indicating this information, the virtual image V also includes a background portion, which is, for example, rectangular in a plan view from the occupant.

In addition, HUD1 mainly operates in two modes. One is a display mode in which the virtual image V can be visually recognized from the viewpoint EP by projecting the display light Li onto the windshield WS as shown in FIG. The other is a pause mode (parking mode) in which the HUD1 does not project the display light Li on the windshield WS and the virtual image V cannot be visually recognized from the viewpoint EP. In the parking mode HUD1 that does not project the display light Li onto the windshield WS, the display light Li is incident on the external light (mainly sunlight) that is incident on the HUD1 from the direction of the windshield WS based on the principle of reversal of light rays. It is in a position where it does not reflect in the direction (the direction in which the display unit is optically present). As a result, when the HUD1 in which the vehicle C is considered to be stopped is in the parking mode, it is possible to prevent the display unit from being illuminated by external light and becoming in a high temperature state.
The HUD1 rotates the reflecting unit 30 according to the configuration described later in order to switch between these modes.

In the display mode HUD1, the optical path of the display light Li can be changed by the configuration described later in order to adjust the height of the viewpoint EP in which the virtual image V can be visually recognized. In the present disclosure, as shown in the drawings, it is possible to change to three types: shorter display light Ls, center display light Lc, and torah display light Lt. As for the shorter display light Ls, in the display mode, the HUD1 projects the display light Li onto the relatively lower portion of the windshield WS to project the virtual image V. In the Torah display light Lt, the HUD1 projects the display light Li onto the relatively upper part of the windshield WS to project the virtual image V. In the center display light Lc, the virtual image V is projected by passing between the above-mentioned two display optical paths.

The HUD 1 includes a control unit, an upper case 11, a lower case 12, a display unit 20, a reflection unit 30, and a bearing unit 40.

The control unit is provided with a storage unit such as a ROM or RAM (not shown) used for storing a predetermined program or various data, a storage area at the time of calculation, a CPU for performing calculation processing according to the predetermined program, an input / output interface, and the like. Microcomputer can be applied. The control unit is electrically connected to the display unit 20, the power unit, and an external electronic device of the HUD1. The control unit generates an image to be displayed on the display unit 20, controls the display of the display unit 20, controls the illuminance of the display unit 20, and controls the illuminance of the display unit 20 based on the vehicle information received from the in-vehicle device external to the HUD1. Controls the rotation of the reflecting unit 30.

The upper case 11 and the lower case 12 are housings for fixing the members provided in the HUD 1 by known means such as adhesion, fitting, and screwing. For example, the lower case 12 fixes a display unit 20, a control unit (not shown), and a bearing unit 40. Further, the upper case 11 is a lid-shaped housing provided so as to cover the lower case 12 from above, and has a window portion 111 through which the indicator light Li passes in the center. The window portion 111 may be closed with a transparent hard synthetic resin (acrylic, polycarbonate, or the like). The user of the vehicle C can visually recognize the inside of the HUD1 only through the window portion 111.

The display unit 20 is a member that emits the display light Li. In the present disclosure, the light is emitted toward the direction F. As a member that emits the display light Li, for example, a configuration using a TFT liquid crystal module, a configuration using an organic EL, a projector using a DMD (Digital Micro-mirror Device), or the like can be applied. In the configuration using the TFT liquid crystal module, for example, the display unit 20 is provided with the backlight unit and the liquid crystal display element connected to the control unit in a fixed state, and the liquid crystal display element that displays information under the control of the control unit. Is illuminated by the illumination light emitted from the backlight unit whose blinking is controlled by the control of the control unit to emit the display light Li. However, it goes without saying that the effects of the configuration of the present disclosure can be exhibited as long as the configuration is capable of emitting display light other than those illustrated.

As shown in FIG. 3, the reflecting unit 30 is provided with a reflecting mirror 31 and a holder 32.
The reflector 31 reflects the display light Li. For example, the surface of the reflecting mirror 31 that reflects the display light Li has a concave free curved surface shape, and the mirror surface is formed by a method such as vapor deposition or sputtering. The reflecting mirror 31 reflects the display light Li while enlarging it. For the reflector 31, a hard synthetic resin or inorganic glass can be applied to the base material. Further, it is desirable that the reflecting surface 31a has a shape that cancels the distortion of the virtual image V that is assumed to occur in the windshield WS due to the shape of the free curved surface.

The holder 32 is a holding member for fixing the reflector 31 by a known means such as adhesion or screwing. Further, the holder 32 rotatably holds the reflector 31 about the rotation axis A. As the material of the holder 32, a hard metal such as magnesium or iron or a hard synthetic resin such as ABS resin can be applied.

The holder 32 is provided with a shaft 33 and a holder lever (not shown).
The holder lever is a protruding arm piece provided on the holder 32. By pressing the holder lever from a power unit (not shown), the reflection unit 30 can be rotated around the rotation axis A. For the power unit, for example, a configuration using a lead screw and a motor can be applied. Specifically, a drive unit such as a motor that rotates the rotating shaft in response to an input signal, a screw shaft that rotates in response to the rotation, a ring-shaped nut portion that is screwed into the screw shaft, and a guide that suppresses the rotation of the nut portion. It has a part, and the power transmission part described later is fixed to the nut. The nut portion whose rotation is suppressed by the guide portion can perform a linear motion along the axial direction of the screw shaft rotated by the drive portion. The position of the holder lever is displaced based on this linear motion, and the reflecting portion 30 rotates. However, the power unit may be any power unit that generates torque enough to rotate the reflection unit 30, and may be configured by using a motor, a transmission gear, a worm gear, a rack and pinion, or the like.

In the present embodiment, the mode in which the reflecting unit 30 is composed of the reflecting mirror 31 and the holder 32 is shown. However, the shaft and the holder lever may be provided integrally with the reflector. In this case, the HUD can be made smaller, or the manufacturing cost can be reduced by reducing the number of members.

As shown in FIG. 4, the bearing portion 40 has a press-fit hole 41 and a slide bearing 50. FIG. 4 is a diagram showing a cross section of one of the two bearing portions 40 provided in the head-up display 1 located in the L direction.

The bearing portion 40 is an attachment for fixing the slide bearing 50 to the lower case 12. The slide bearing 50 has a press-fit hole 41 which is a hole having a size about the outer shape of the tubular portion 51 of the slide bearing 50, and the slide bearing 50 is press-fitted therein. Therefore, it is desirable that the bearing portion 40 is made of a material (hard metal such as stainless steel or hard synthetic resin such as ABS) that is rigid enough to withstand positioning and press fitting.

The slide bearing 50 is a slide bearing for improving the slidability when the reflective portion 30 rotates. In the present embodiment, the slide bearing 50 is a slide bearing in which a plate material is wound in a cylindrical shape. This plate material includes an electrogalvanized steel sheet (SECC) having a thickness of 0.25 mm, a copper wire mesh as a reinforcing material placed on the back metal of the electrogalvanized steel sheet, and polytetrafluoroethylene (polytetrafluoroethylene) covering the wire mesh. It includes an overlay layer made of PTFE). This plate material has, for example, a thickness of 0.75 mm.

As shown in FIG. 5, the slide bearing 50 is formed by a tubular portion 51, a flange portion 52, and a mating surface 53. That is, the slide bearing 50 of the present disclosure is a bush with a flange.

The tubular portion 51 forms a bearing surface 511. The bearing surface 511 forms a cylindrical space in which the shaft 33 is formed. The shaft 33 can be inserted into the bearing surface 511 by making the inner diameter of the bearing surface 511 about the outer diameter of the shaft 33. It is desirable that the bearing surface 511 has a surface structure in which friction is unlikely to occur, and it is desirable that the bearing surface 511 is formed of, for example, the overlay layer described above.

The slide bearing 50 can be press-fitted into the press-fit hole 41 by roughly matching the outer shape of the tubular portion 51 with the inner diameter of the press-fit hole 41. That is, FIG. 4 shows the bearing portion 40 in a state where the slide bearing 50 is press-fitted.

The flange portion 52 is provided with a surface having good slidability on a surface facing the R direction continuously from the bearing surface 511. Further, in the present disclosure, the slide bearing 50 is assembled so that the flange portion 52 faces the reflector 31. According to this configuration, as shown in FIG. 4, even when the reflective portion 30 is displaced in the thrust direction, the side surface of the shaft 33 comes into contact with the flange portion 52 having good slidability, so that the slidability is maintained to some extent. Can be maintained.
The combined surface 53 is a joint surface formed when the plate material is wound into a cylindrical shape.

<About shaft shape>
The shaft 33 has a shape as shown in FIGS. 4 and 6. The shape of the shaft 33 is formed by two, a sliding surface 331 in contact with the bearing surface 511 and a chipped portion 332 not in contact with the bearing surface 511.

The shaft 33 having the chipped portion 332 can improve the slidability. In particular, when viewed from the cross section including the rotating shaft A, it is more preferable that the sliding surface 331 and the bearing surface 511 are in contact with each other at a plurality of points in the thrust direction. This is because, when the contact area is the same, it is not preferable to make contact at only one place in terms of suppressing shaft shake. On the other hand, if the sliding surface 331 is formed so as to be partially separated and contacted in the thrust direction, it is effective in suppressing the shake of the shaft. That is, a shaft such as the shaft 33, which is formed by a plurality of sliding surfaces 331 separated in the thrust direction, can improve slidability and suppress shaft shake.

The inventor made measurements on some shaft shapes in order to evaluate the slidability. The measurement was performed by inserting the shaft into the jig on which the slide bearing 50 was installed, rotating the shaft so as to make one revolution in about 6 seconds, and recording the torque required for the rotation at that time. FIG. 7 is a graph showing the slidability of the shaft based on this measurement. The vertical axis of the graph shows the torque (Nm) required for rotation on a linear scale. The horizontal axis of the graph indicates time (s) on a linear scale. For convenience, FIG. 7 also displays the measurement results of the shaft 33 of the present embodiment, the shafts 34 and 35 described later, and the columnar shaft as a conventional example.

As shown in FIG. 7, the torque required to rotate the shaft 33 is substantially constant throughout the measurement time. This is because the chipped portion 332 of the shaft 33 has a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis A. That is, in the present embodiment, since the chipped portion 332 forms an annular shape centered on the rotation axis A, it is realized that the required rotation torque becomes constant regardless of the direction in which the shaft 33 is oriented. ing. The constant required rotational torque greatly contributes to smooth position adjustment of the virtual image V in the head-up display. That is, according to this configuration, the head-up display has improved smoothness of rotation of the reflecting portion.

Although the head-up display of the present invention has been described by way of examples in the configuration of the above-described embodiment, the present invention is not limited to this, and other configurations also deviate from the gist of the present invention. Of course, it is possible to make various improvements and change the display within the range that does not apply.

[First modification]
In the first embodiment, the head-up display 1 composed of the shaft 33 is shown, but the shaft 33 may be the shaft 34 as shown in FIG. That is, the chipped portion of the shaft does not have to have a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis A. In the shaft 34, the sliding surface 341 is formed by three forks.

The result of measuring the slidability of the shaft 34 using the slide bearing 50 is shown in FIG. While the shaft 34 goes around, the rotational torque has a peak in the positive direction of the vertical axis about 3 times. That is, in a shape like the shaft 34, the torque required for rotation changes according to the direction of the shaft.

The cause of this is mainly the shape of the slide bearing 50. As described above, the slide bearing 50 is formed by winding a plate material into a cylindrical shape. In this production, it is difficult to make the bearing surface 511 a true cylinder, and the bearing surface has a slightly elliptical shape. That is, the bearing surface has a fine short side and a long side.

On the other hand, the shaft 34 has a three-pronged sliding surface 341. Since the three-pronged shape is not a circle, the width and height differ depending on the orientation. For example, in an ideal three-pronged shape (that is, an equilateral triangle shape) that ignores the area of the sliding surface, the width and height fluctuate from (√3) r to 3r / 2 when the radius of the shaft 34 is r. ..

This change in width and height and the relationship between the lateral direction and the longitudinal direction of the ellipse cause a positional relationship that requires rotational torque. Therefore, when such a shaft 34 is used, the slidability of the reflective portion 30 can be improved by applying a positional relationship in which the rotational torque characteristic is small to the actual use angle of the reflective portion 30 in the head-up display 1. Can be done. The small torque required for rotation leads to a reduction in the rotational load.
Even with this configuration, the head-up display has improved smoothness of rotation of the reflecting portion.

[Second modification]
Further, the shaft 33 may be a shaft 35 as shown in FIG. Also in the shaft 35, the chipped portion 352 does not form a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis A. Therefore, the rotational torque characteristic of the shaft 35 shown in FIG. 7 changes according to the orientation of the shaft 35. Therefore, even when the shaft 35 is used, it is preferable to rotate the reflecting portion 30 at a position where the rotational torque required for rotation is small. Even with this configuration, the head-up display has improved smoothness of rotation of the reflecting portion. Further, the shaft 35 may have elasticity in the radial direction by being formed in a Z-shape or the like.

[Other variants]
In the first embodiment, the sliding surfaces 331 are separated into three. However, the present invention is not limited to this configuration, and may be separated by any number.

In the first modification, the three-pronged shaft 34 is shown, but the present invention is not limited thereto. For example, the shaft may be further divided to form a cross-shaped column. Further, the shaft may have a spiral structure instead of a columnar structure as in the first embodiment. When a spiral structure is applied to a three-pronged column such as the shaft 34, the sliding surface 341 forms a so-called triple helix structure. That is, if the shaft is provided with a chip portion provided so as to reduce the contact area between the shaft and the bearing surface, the smoothness of rotation of the reflecting portion can be improved.

[Effect example]
First, the head-up display 1 of the present disclosure is
It is a head-up display 1 that projects a virtual image V by projecting the display light Li onto the windshield WS.
The display unit 20 that emits the display light Li and
A reflecting unit 30 that reflects the display light Li and can adjust the direction in which the display light Li is reflected by rotating around a predetermined rotation axis A.
A plain bearing 50 having a bearing surface 511 that defines the rotating shaft A, and the like.
The reflecting portion 30 has shafts 33, 34, 35 inserted into the slide bearing 50, and has shafts 33, 34, 35.
The shafts 33, 34, 35
Sliding surfaces 331, 341, 351 that slide in contact with the bearing surface 511,
The sliding surfaces 331, 341, and 351 have chipped portions 332,342,352 so that the contact area with the bearing surface 511 is reduced.

According to this configuration, the head-up display can improve the slidability of the rotatable reflective portion 30.

Secondly, the head-up display 1 of the present disclosure is
The chipped portion 332 has a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis A.

According to this configuration, the head-up display has a constant torque required for rotation.

Thirdly, the head-up display 1 of the present disclosure is
The slide bearing 50 is formed by winding a plate material into a cylindrical shape.
The chipped portions 342 and 352 are not formed in a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis A.
The shafts 34 and 35 are positioned with respect to the elliptical shape of the slide bearing so that the rotational load is reduced at the angle used for rotation.

1 Head-up display 11 Upper case 110 Window part 12 Lower case 20 Display part 30 Reflection part 31 Reflector 32 Holder 33,34,35 Shaft 331,341,351 Sliding surface 332,342,352 Missing part 40 Bearing part 41 Press-fitting Hole 50 Slide bearing 51 Cylinder part 511 Sliding surface 52 Flange part

C Vehicle Li Display light A Rotation axis WS Windshield EP Viewpoint (eye point)

Claims (3)

A head-up display that projects a virtual image by projecting display light onto a reflective and transmissive member.
A display unit that emits the display light and
A reflecting unit that reflects the display light and can adjust the direction in which the display light is reflected by rotating around a predetermined rotation axis.
A plain bearing having a bearing surface that defines the rotation axis, and
The reflective portion has a shaft that is inserted into the slide bearing.
The shaft
A sliding surface that slides in contact with the bearing surface,
A head-up display having a chipped portion in which the sliding surface is lightened so as to reduce the contact area with the slide bearing. The head-up display according to claim 1, wherein the chipped portion has a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis. The slide bearing is formed by winding a plate material into a cylindrical shape.
The chipped portion is not formed in a rotating body shape that can be represented by rotating a predetermined figure around the rotation axis.
The head-up display according to claim 1, wherein the shaft is positioned with respect to the elliptical shape of the slide bearing so that the rotational load is reduced at an angle used for rotation.

Images