Mirror unit and head-up display device

Abstract

To provide a mirror unit and a head-up display device capable of suppressing deterioration of image quality while enhancing strength with a simple configuration.SOLUTION: The mirror unit 30 includes a main body plate portion 31 having a substantially rectangular plate shape, a reflective layer 32 that is formed on one front surface of the main body plate portion 31 and reflects the display light, two shaft portions 33L and 33R provided at end portions on both sides in the X direction, and a rib 35a to a rib 35d that are erected on the other rear surface 31B of the main body plate portion 31 and extend in the rib extending direction V. The widths of the ribs 35a to 35d in the direction orthogonal to the rib extension direction V are formed to have a length of 50% or more of the thickness of the body plate portion 31.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a mirror unit and a head-up display device. [Background technology]

[0002] The head-up display device described in Patent Document 1 includes a mirror unit that reflects display light from a display unit onto the windshield. This mirror unit includes a concave mirror and a holder that supports the concave mirror from the backside. The holder is made of synthetic resin and has a rectangular plate shape, and multiple ribs are formed on the backside of the holder to improve its strength (see paragraph 0022 and Figure 7 of Patent Document 1).

[0003] The concave mirror of the head-up display device described in Patent Document 2 has a reflective surface formed by depositing metal (for example, aluminum) on resin (see paragraph 0015 of Patent Document 2).

[0004] The positioning structure described in Patent Document 3 includes a positioning pin made of a rib extending in three or four directions from the center. Patent Document 3 also discloses that if the width of this rib is 50% or less of the thickness of the design surface, sink marks will not occur on the design surface (see paragraph 0015 of Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2019 / 124331 [Patent Document 2] Patent Publication No. 2021-154929 [Patent Document 3] Japanese Patent Application Laid-Open No. 2005-277349 Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration described in Patent Document 1, the concave mirror and the holder were manufactured separately and were adhered to the concave mirror at the adhesive surface of the holder, but the concave mirror and the holder had to be constructed separately, which made the configuration inconvenient. The configuration in which a reflective surface is vapor-deposited on a holder described in Patent Document 2 is a simple configuration, but if ribs are provided in this configuration, increasing the width of the ribs to increase strength could result in sink marks, which could reduce the shape accuracy of the reflective surface and the image quality of the projected image based on the reflected display light.

[0007] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a mirror unit and a head-up display device that have a simple configuration, are stronger, and can suppress degradation of image quality. [Means for solving the problem]

[0008] In order to achieve the above object, a mirror unit according to a first aspect of the present disclosure comprises: a substantially rectangular main body plate portion made of synthetic resin; a reflective layer formed on one surface of the main body plate portion and reflecting display light; Two shaft portions provided at both longitudinal end portions of the main body plate portion; a rib extending in a rib extending direction and erected on the other surface of the main body plate portion, The width of the rib in a direction perpendicular to the rib extending direction is 50% or more of the thickness of the main body plate portion.

[0009] In order to achieve the above object, a head-up display device according to a second aspect of the present disclosure includes: a display device that emits display light; the mirror unit that reflects the display light; and a mirror drive mechanism that rotates the mirror unit around a rotation axis that passes through the two shaft portions and is inclined with respect to the longitudinal direction. [Effects of the Invention]

[0010] According to the present disclosure, it is possible to suppress degradation of image quality while increasing strength with a simple configuration. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic diagram of a vehicle equipped with a head-up display device according to an embodiment of the present disclosure. [Figure 2] 1 is a schematic diagram illustrating a configuration of a head-up display device according to an embodiment of the present disclosure. [Figure 3] FIG. 1 is a perspective view of a mirror unit according to an embodiment of the present disclosure. [Figure 4] FIG. 1 is a perspective view of a mirror unit according to an embodiment of the present disclosure. [Figure 5] FIG. 2 is a plan view of a mirror unit according to an embodiment of the present disclosure. [Figure 6] FIG. 2 is a rear view of a mirror unit according to an embodiment of the present disclosure. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] FIG. 10 is a perspective view of a mirror unit according to a modified example of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] A mirror unit and a head-up display device according to an embodiment of the present disclosure will be described with reference to the drawings. As shown in Fig. 1, the head-up display device 100 is installed in the dashboard of a vehicle 200. The head-up display device 100 emits display light L that displays an image toward a windshield 201, which is an example of a projection target member of the vehicle 200. The display light L is reflected by the windshield 201 and reaches a viewer 1 (mainly the driver of the vehicle 200). As a result, the head-up display device 100 displays a virtual image Q so as to be superimposed on a real scene seen through the windshield 201.

[0013] As shown in FIG. 2, the head-up display device 100 includes a display device 10, a folding mirror 20, a mirror unit 30, a mirror drive mechanism 50, and a housing 60.

[0014] The housing 60 is made of a non-transparent resin material or a metal material and has a hollow, substantially rectangular parallelepiped shape. The housing 60 accommodates the folding mirror 20, the mirror unit 30, and the mirror drive mechanism 50. The housing 60 has an opening 61a formed in a position facing the windshield 201. The housing 60 has a curved plate-shaped window 65 that closes the opening 61a. The window 65 is made of a translucent resin material such as acrylic, through which the display light L passes.

[0015] The display device 10 emits display light L under the control of a control unit (not shown). The display device 10 includes a TFT (Thin Film Transistor) liquid crystal display panel 11 and a backlight 12 that illuminates the display panel 11. Note that, although the display device 10 is of a type including the display panel 11, it is not limited to this and may be of any type as long as it is capable of emitting display light L. The display device 10 may be, for example, a type including an OLED (Organic Light-Emitting Diode), a type that receives light reflected by a DMD (Digital Micromirror Device) and displays an image on a transmissive screen, or the like.

[0016] The folding mirror 20 is a correcting mirror that reflects the display light L from the display device 10 toward the mirror unit 30. The reflecting surface 20a of the folding mirror 20 is a curved surface that is convex in the vehicle width direction and concave in the height direction. The reflecting surface 20a has a curvature (the reciprocal of the radius of curvature) that causes the reflected display light L to cross above and below at a cross point CP before reaching the mirror unit 30. The folding mirror 20 is not limited to a curved mirror, but may be a flat mirror.

[0017] The mirror unit 30 is a concave mirror unit, and magnifies and reflects the display light L reflected by the folding mirror 20 toward the windshield 201. The specific configuration of the mirror unit 30 will be described later.

[0018] The mirror drive mechanism 50 is configured to rotate the mirror unit 30 around a rotation axis J extending along the vehicle width direction. By rotating the mirror unit 30 around the rotation axis J, the irradiation position of the display light L with respect to the viewer 1 is adjusted in the height direction.

[0019] As shown in FIGS. 3 to 6, the mirror unit 30 includes a main body plate portion 31, a reflective layer 32, shaft portions 33L and 33R, ribs 35a to 35d, connecting portions 37 and 38, and a plate portion . In the following description, the longitudinal direction of the mirror unit 30 is the X direction, the lateral direction of the mirror unit 30 is the Y direction, and the thickness direction of the mirror unit 30 is the Z direction. The X direction corresponds to the left-right direction of the virtual image Q as seen by the viewer 1, i.e., the vehicle width direction, the Y direction corresponds to the up-down direction of the virtual image Q as seen by the viewer 1, and the Z direction corresponds to the depth direction of the virtual image Q as seen by the viewer 1. In the following description, left and right are defined as directions when the reflecting surface of the mirror unit 30 is viewed from the front.

[0020] The main body plate portion 31, the shaft portions 33L and 33R, and the ribs 35a to 35d are integrally molded from synthetic resin as synthetic resin products. The shaft portion 33L may be formed separately from the main body plate portion 31, the shaft portion 33R, and the ribs 35a to 35d. The main body plate portion 31 has a generally rectangular plate shape that is long in the X direction and short in the Y direction. The main body plate portion 31 has a curved shape that is concavely curved in both the X and Y directions.

[0021] The upper and lower side surfaces of the main body plate portion 31 extend parallel to the X direction. The reflective layer 32 is formed on the front surface (surface on the folding mirror 20 side) of the main body plate portion 31. The reflective layer 32 is formed on the front surface of the main body plate portion 31 by vapor deposition of a metal such as aluminum.

[0022] The shafts 33L and 33R are located at both ends of the main body plate 31 in the X direction. The shaft 33R is located on the right side surface of the main body plate 31 and has a generally cylindrical shape extending in the X direction. The shaft 33R is located above the center in the Y direction on the right side surface of the main body plate 31. The shaft 33R is housed in a housing recess (not shown) in the housing 60, and in this housed state, the shaft 33R is biased by a plate spring (not shown), so that the shaft 33R is rotatably supported within the housing 60.

[0023] The shaft 33L is located on the left side surface of the main body plate 31 and has a rectangular plate shape. The shaft 33L is located lower than the center in the Y direction on the right side surface of the main body plate 31. A receiving member 39 shown by the dashed dotted line in Figure 3 is attached to the shaft 33L. When the receiving member 39 receives a driving force from the mirror driving mechanism 50, the mirror unit 30 rotates around the rotation axis J.

[0024] The rotation axis J of the mirror unit 30 is tilted with respect to the X direction. The tilt angle θ (see FIG. 6) of the rotation axis J with respect to the X direction is set to 2° to 5°, preferably about 3.5°.

[0025] The ribs 35a to 35d are provided upright on the rear surface 31B of the main body plate portion 31 (the surface opposite to the reflective layer 32). The ribs 35a to 35d extend in a rib extension direction V. The ribs 35a to 35d are formed to traverse the entire area of ​​the back surface 31B of the main body plate portion 31 in the X direction. The ribs 35a to 35d extend parallel to one another. The rib extension direction V extends in the direction of the rotation axis J and is inclined with respect to the X direction (the direction in which the upper and lower side surfaces of the main body plate portion 31 extend). The inclination angle α (see FIG. 6) of the rib extension direction V with respect to the X direction is set to 2° to 5°, preferably approximately 3.5°.

[0026] The ribs 35b and 35c are arranged in the Y direction to sandwich the rotation axis J. The ribs 35a and 35d are arranged in the Y direction to sandwich the ribs 35b and 35c.

[0027] The ribs 35b, 35c have inclined portions 35b1, 35c1 located at the end on the shaft 33L side in the rib extension direction V. The inclined portions 35b1, 35c1 are inclined so as to approach the rotation axis J as they approach the shaft 33L. The outer ends of the inclined portions 35b1, 35c1 in the rib extension direction V are connected to the connecting portion 37. The connecting portion 37 is located at the end on the shaft 33L side of the back surface 31B and forms a rectangular parallelepiped extending in the Y direction. The ribs 35b and 35c may be formed in a straight line along the rotation axis J over their entire length without being provided with an inclined portion. However, such inclined portions 35b1 and 35c1 may be provided to avoid positions where the eject pin may come into contact.

[0028] The ribs 35b, 35c have inclined portions 35b2, 35c2 located at the end on the shaft 33R side in the rib extension direction V. The inclined portions 35b2, 35c2 are inclined so as to move away from the rotation axis J as they approach the shaft 33R. The outer ends of the inclined portions 35b2, 35c2 in the X direction are connected to the connecting portion 38. The connecting portion 38 is located at the end on the shaft 33R side of the back surface 31B and forms a rectangular parallelepiped extending in the Y direction. The connecting portion 38 is formed on both sides in the Y direction of the base portion of the shaft 33R. In this regard, the ribs 35b and 35c may be formed in a straight line along the rotation axis J over their entire length without being provided with an inclined portion. However, such inclined portions 35b2 and 35c2 may be provided to avoid positions where the eject pin comes into contact.

[0029] Recesses 35b3 and 35c3 are formed at the center of the opposing surfaces of the ribs 35b and 35c in the rib extension direction V. The recesses 35b3 and 35c3 are formed so that the hole width in the rib extension direction V increases toward the opposing sides. The recesses 35b3 and 35c3 are portions into which an ejector pin (not shown) fits during injection molding. The ejector pin is preferably located in a position where it does not interfere with the rib. Furthermore, if the ejector pin can be located in a position where it does not interfere with the rib, the ribs 35b and 35c are preferably formed in a straight line along the rotation axis J over their entire length.

[0030] 7, the width W of the rib 35c is formed to be 50% or more of the plate thickness Th of the main body plate portion 31. The width W of the rib 35c is the length in a direction perpendicular to the rib extending direction V. The width W of the rib 35c refers to the width of the base portion of the rib 35c. The width W of the rib 35c is set to 2 mm to 6 mm, preferably 3.0 mm to 4.5 mm, and more preferably about 3.8 mm. The plate thickness Th is set to 2 mm to 6 mm, preferably 3.0 mm to 4.5 mm, and more preferably about 3.8 mm.

[0031] If the ratio of the width W to the plate thickness Th is too small, the strength of the mirror unit 30 will be reduced, causing the resonant frequency to drop and making it more likely to vibrate; if this ratio is too large, there is a risk of sink marks occurring on the surface of the main body plate portion 31. From this perspective, the width W of the rib 35c is set to 50% to 150%, preferably 80% to 120%, more preferably 90% to 110%, and more preferably approximately 100% of the thickness Th of the main body plate portion 31. As an example, both the width W and the thickness Th are set to approximately 3.8 mm. The width W of the ribs 35a, 35b, and 35d other than the rib 35c is set to be the same as the width W of the rib 35c described above.

[0032] The height of the ribs 35a and 35d relative to the rear surface 31B is set to be higher than the height of the ribs 35b and 35c relative to the rear surface 31B. However, this is not limited to this example, and the heights of the ribs 35a to 35d may be the same.

[0033] The plate portion 36 is formed in a plate shape and stands on the rear surface 31B, extending on the rotation axis J. The thickness of the plate portion 36 is formed to be smaller than the width W of each of the ribs 35a to 35d. The ribs 35a to 35d and the plate portion 36 are arranged at equal intervals in the Y direction.

[0034] As described in Patent Document 3, when forming ribs on a typical injection-molded product, if the rib is not 50% or less of the thickness of the injection-molded product, sink marks will occur on the surface of the injection-molded product (the surface opposite the rib) after normal cooling time. In this regard, since cooling takes a relatively long time when injection molding the synthetic resin part of the mirror unit 30, sink marks do not occur on the surface of the main body plate portion 31 even if wide ribs 35a-35d with a thickness ratio of 50% or more are formed to improve the strength of the mirror unit 30. In other words, the cooling time is set to a time that does not cause sink marks to occur on the surface of the main body plate portion 31. Therefore, the strength of the mirror unit 30 is improved without requiring special consideration in manufacturing. By improving the strength of the mirror unit 30, the resonance frequency of the mirror unit 30 can be increased, and vibration of the mirror unit 30 can be suppressed.

[0035] (effect) According to the embodiment described above, the following effects are achieved. (1) The mirror unit 30 includes a substantially rectangular main plate 31 made of synthetic resin, a reflective layer 32 formed on one surface of the main plate 31 and reflecting display light L, two shafts 33L and 33R provided at both ends of the main plate 31 in the longitudinal direction (X direction), and ribs 35a to 35d erected on the other back surface 31B of the main plate 31 and extending in a rib extending direction V. The width W of the ribs 35a to 35d in a direction perpendicular to the rib extending direction V is set to be 50% or more of the thickness (plate thickness Th) of the main plate 31. According to this configuration, the reflective layer 32 is formed on the main body plate portion 31, which is a simple configuration, and wide ribs a to 35d are formed to increase the strength of the mirror unit 30, while sink marks are not generated as described above, which makes it possible to suppress deterioration in the image quality of the projected image based on the display light L reflected by the mirror unit 30.

[0036] (2) The mirror unit 30 is configured to be rotatable about a rotation axis J that passes through the two shaft portions 33L, 33R and is inclined with respect to the X direction. The ribs 35a to 35d are formed along the direction of the rotation axis J. According to this configuration, the ribs 35a to 35d are formed along the direction of the rotation axis J, and thus the strength of the mirror unit 30 is improved.

[0037] (3) The head-up display device 100 includes a display device 10 that emits display light L, a mirror unit 30 that reflects the display light L, and a mirror drive mechanism 50 that rotates the mirror unit 30 about a rotation axis J. According to this configuration, deterioration in the quality of the projected image (virtual image Q) displayed on the head-up display device 100 can be suppressed.

[0038] (Variation) The above embodiment can be modified as follows. In the above embodiment, the positions or shapes of the shafts 33L and 33R can be changed, and the shafts 33L and 33R may be omitted. In the above embodiment, the mirror driving mechanism 50 may be omitted. In the above embodiment, the plate portion 36 may be formed as a rib or may be omitted. In the above embodiment, the rotation axis J may extend in the X direction.

[0039] In the above embodiment, the head-up display device 100 is mounted on the vehicle 200, but it may be mounted on a vehicle other than the vehicle 200, such as an airplane or a ship. In addition, the projection member is not limited to the windshield, and may be a dedicated combiner. In the above embodiment, the mirror unit 30 is a concave mirror unit. The mirror unit may be a flat mirror unit or a free-form surface mirror unit.

[0040] In the above embodiment, the number, position, shape, or width W of the ribs 35a to 35d can be changed as appropriate. The ribs 35a to 35d may extend in the X direction. In this case, the rib extension direction V is the same as the X direction. The ribs may also extend in the Y direction on the back surface 31B. The ribs 35a to 35d may be formed in a curved shape.

[0041] Furthermore, for example, the number of ribs 35a to 35d may be one to three, or five or more. As shown in FIG. 8, the mirror unit 130 has five ribs 135a to 135e, each extending in a rib extending direction V and gathered on the rotation axis J side at both ends in the rib extending direction V. The rib 135e extends on the rotation axis J. The ribs 135b and 135c are arranged so as to sandwich the rib 135e in the Y direction, and extend linearly in the rib extending direction V over the entire area of ​​the rear surface 31B. The ribs 135a and 135d are arranged so as to sandwich the ribs 135b and 135c in the Y direction. The ribs 135a and 135d have inclined portions 136a and 136d located at both ends in the rib extension direction V. The inclined portions 136a and 136d are inclined toward the rotation axis J as they approach both outer sides in the rib extension direction V. [Explanation of symbols]

[0042] 1...Viewer 10... display device, 11... display panel, 12... backlight 20...folding mirror, 20a...reflecting surface, 30, 130... mirror unit, 31... main body plate portion, 31B... rear surface, 32... reflective layer, 33L, 33R... shaft portion, 35a to 35d, 135a to 135e... ribs, 35b1, 35c1, 35b2, 35c2, 136a, 136d... inclined portions, 35b3, 35c3... recesses, 36... plate portion, 37, 38... connecting portion, 39... receiving member 50...Mirror drive mechanism 60... housing, 61a... opening, 65... window 100...Head-up display device 200...Vehicle, 201...Windshield J...Rotation axis, L...Display light, V...Rib extension direction, Q...Virtual image, CP...Cross point, Th...Plate thickness, W...Width, θ,α...Inclination angle

Claims

1. a substantially rectangular main body plate portion made of synthetic resin; a reflective layer formed on one surface of the main body plate portion and reflecting display light; two shaft portions provided at both longitudinal end portions of the main body plate portion; a rib extending in a rib extending direction and erected on the other surface of the main body plate portion, The width of the rib in a direction perpendicular to the rib extending direction is 50% or more of the thickness of the main body plate portion. Mirror unit.

2. the mirror unit is configured to be rotatable about a rotation axis that passes through the two shaft portions and is inclined with respect to the longitudinal direction, The rib is formed along the direction of the rotation axis.

2. The mirror unit according to claim 1.

3. a display device that emits display light; The mirror unit according to claim 1 or 2, which reflects the display light; a mirror drive mechanism that rotates the mirror unit around a rotation axis that passes through the two shaft portions and is inclined with respect to the longitudinal direction, Head-up display device.

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