JP7735766B2 - Head-up display - Google Patents

Description

The present invention relates to a head-up display mounted on a vehicle, etc.

A head-up display reflects display light, which shows an image generated by a display device, off a reflective member such as a concave mirror, and then emits it outside the device through an opening in the case. The emitted display light then illuminates a transmissive reflective member such as a windshield, allowing the viewer to see a virtual image.

The opening of the case is curved and covered with a light-transmitting sheet. For example, in Patent Document 1, the light-transmitting sheet is fixed by a fixing frame.

International Publication No. 2020-9092

In the head-up display of Patent Document 1, the fixing pins are exposed to the outside. Having the fixing points exposed to the outside could reduce dustproof performance.

The present invention was made in consideration of these circumstances, and aims to provide a head-up display that has improved dust resistance while still retaining a translucent sheet.

In order to solve the above-mentioned problems, the head-up display according to the present invention comprises:
a display device that outputs display light;
a light-transmitting sheet having a light-transmitting property and a sheet periphery;
a case for accommodating the display device, the case including: an opening covered with the light-transmitting sheet and for emitting the display light to the outside through the light-transmitting sheet; and a sheet holding portion located on a periphery of the opening and holding a periphery of the sheet;
a fixing frame that covers the periphery of the sheet and fixes the light-transmitting sheet to the sheet holding portion,
The fixing frame has a fixing pin,
the light-transmitting sheet has a through-hole through which the fixing pin passes,
the sheet holding portion fixes the light-transmitting sheet between the fixing frame and the fixing pin by fixing the fixing pin to a fixing hole provided in the case;
The fixing frame has a first wall that abuts against the periphery of the through hole .
In order to solve the above-mentioned problems, a head-up display according to another aspect of the present invention comprises:
a display device that outputs display light;
a light-transmitting sheet having a light-transmitting property and a sheet periphery;
a case for accommodating the display device, the case including: an opening covered with the light-transmitting sheet and for emitting the display light to the outside through the light-transmitting sheet; and a sheet holding portion located on a periphery of the opening and holding a periphery of the sheet;
a fixing frame that covers the periphery of the sheet and fixes the light-transmitting sheet to the sheet holding portion,
The fixing frame has a fixing pin,
the light-transmitting sheet has a through-hole through which the fixing pin passes,
the sheet holding portion fixes the light-transmitting sheet between the fixing frame and the fixing pin by fixing the fixing pin to a fixing hole provided in the case;
The sheet holding portion has a second wall that is inserted into the through-hole and is higher than the light-transmitting sheet.
In order to solve the above-mentioned problems, a head-up display according to another aspect of the present invention comprises:
a display device that outputs display light;
a light-transmitting sheet having a light-transmitting property and a sheet periphery;
a case for accommodating the display device, the case including: an opening covered with the light-transmitting sheet and for emitting the display light to the outside through the light-transmitting sheet; and a sheet holding portion located on a periphery of the opening and holding a periphery of the sheet;
a fixing frame that covers the periphery of the sheet and fixes the light-transmitting sheet to the sheet holding portion,
The fixing frame has a fixing pin,
the light-transmitting sheet has a through-hole through which the fixing pin passes,
the sheet holding portion fixes the light-transmitting sheet between the fixing frame and the fixing pin by fixing the fixing pin to a fixing hole provided in the case;
the light-transmitting sheet is fixed in a curved state,
The fixing frame is provided at a portion of the light-transmitting sheet that has the greatest curvature among portions corresponding to the curvature of the light-transmitting sheet, and has a locking portion that is locked to the case.

The head-up display of the present invention can improve manufacturability when attaching the translucent sheet.

1 is a perspective view illustrating an external configuration of a head-up display according to an embodiment of the present invention; FIG. 2 is a schematic cross-sectional view showing the internal configuration of the head-up display. FIG. FIG. FIG. 4 is an enlarged cross-sectional view particularly showing the upper case 51, the light-transmitting sheet 60, and the fixed frame 80.

An embodiment of a head-up display according to the present invention will be described with reference to the accompanying drawings. In this embodiment, an example will be described in which the head-up display according to the present invention is mounted on an automobile, but the present invention can also be applied to head-up displays mounted on motorcycles, ships, agricultural machinery, construction machinery, etc.

Figure 1 is a perspective view illustrating the external configuration of one embodiment of a head-up display according to the present invention.

Figure 2 is a schematic cross-sectional view showing the internal configuration of the head-up display 1.

The head-up display 1 (HUD1) reflects projected display light L toward the viewer (driver) of the vehicle by the vehicle's windshield, which is a transmissive and reflective material, and presents a virtual image (display image) to the viewer. This allows the viewer to observe the virtual image superimposed on the scenery.

HUD 1 is located inside the vehicle's instrument panel. As shown in Figure 2, HUD 1 mainly includes a display device 20, a plane mirror 30, a concave mirror 40, and a case 50.

The display device 20 mainly comprises a light source 21 and a liquid crystal display element 22. The display device 20 outputs display light L. The light source 21 is a light-emitting diode mounted on a wiring board 23. The liquid crystal display element 22 is a TFT-type liquid crystal display element. The liquid crystal display element 22 is disposed in front of (above) the light source 21 so that illumination light from the light source 21 passes through to form display light L. That is, the liquid crystal display element 22 displays display information such as numbers and symbols (e.g., vehicle speed and engine RPM) using light emitted from the light source 21 under the control of an element drive circuit. The display device 20 is fixed and held within the case 50 so that the surface from which the display light L is emitted faces the plane mirror 30 and the optical axis of the display light L intersects with the plane mirror 30.

The plane mirror 30 (reflector) has a base material made of a synthetic resin material and a reflective film formed on the surface of the base material by vapor deposition or the like. The plane mirror 30 reflects the display light L output from the display device 20 toward the concave mirror 40.

The concave mirror 40 has a base material made of a synthetic resin material and a reflective film formed on the surface of the base material by vapor deposition or the like. The concave mirror 40 further reflects the display light L reflected by the plane mirror 30 toward the windshield. The concave mirror 40 functions as a magnifying mirror, enlarging the display image and reflecting it toward the windshield. This allows the viewer to view an enlarged version of the display image displayed by the display device 20. The concave mirror 40 is rotated around its rotation axis by an actuator. By rotating the concave mirror 40, the actuator adjusts the angle of the concave mirror 40 to adjust the irradiation position of the display light L or to an angle that prevents external light from being reflected by the concave mirror 40 toward the display device 20.

The case 50 is made of a light-blocking synthetic resin (e.g., polybutylene terephthalate (PBT)) and has an upper case 51 and a lower case 52. The case 50 forms a box by combining the upper case 51 and the lower case 52, and has an internal space 55 (Figure 2) that primarily houses the display device 20, the plane mirror 30, and the concave mirror 40.

The upper case 51 has an opening 56 located in a portion facing the windshield. The opening 56 is covered with a light-transmitting sheet 60. The attachment structure of the light-transmitting sheet 60 to the upper case 51 will be described later.

The lower case 52 mainly has a structure for mounting the display device 20, the plane mirror 30, and the concave mirror 40.

The light-transmitting sheet 60 is a flat sheet made of a synthetic resin material (e.g., acrylic resin). The light-transmitting sheet 60 has a sheet periphery 60c (Figure 4). The light-transmitting sheet 60 is formed in a curved shape (curved surface) and is attached to the upper case 51 via the sheet periphery 60c. The light-transmitting sheet 60 is translucent, allowing the display light L reflected by the concave mirror 40 to pass through (pass through). In other words, the opening 56 covered by the light-transmitting sheet 60 emits the display light L reflected by the concave mirror 40 to the outside via the light-transmitting sheet 60. The emitted display light L is projected onto the windshield, thereby displaying a virtual image to the viewer.

The curved shape of the light-transmitting sheet 60 is designed to prevent external light reflected by the light-transmitting sheet 60 from reaching the area illuminated by the display light L on the windshield.

Next, the mounting structure of the light-transmitting sheet 60 to the upper case 51 will be described in detail.

Figure 3 is an exploded perspective view particularly showing the upper case 51 and the translucent sheet 60.

Figure 4 is a perspective view showing the fixed frame 80.

Figure 5 is an enlarged view specifically illustrating the upper case 51, the light-transmitting sheet 60, and the fixed frame 80.

The opening 56 of the upper case 51 is covered by a light-transmitting sheet 60 on the outer surface of the upper case 51. The sheet periphery 60c of the light-transmitting sheet 60 is covered by a fixed frame 80. The sheet periphery 60c includes at least an area that overlaps with the sheet holding portion 70 and an area that is covered by the fixed frame 80.

The upper case 51 has a sheet holding portion 70 located on the periphery of the opening 56, which serves as an area for holding the sheet periphery 60c of the light-transmitting sheet 60. The sheet holding portion 70 has four sides that define the opening 56. That is, the sheet holding portion 70 has two opposing sides 75 extending along the Y direction in FIG. 3, which is a first direction, and two opposing sides 76 extending along the X direction, which is a second direction perpendicular to the Y direction. These sides 75, 76 have a fixed width from the opening periphery 56c. The sheet holding portion 70 is convex on the surface 51a facing upward (Z direction) of the upper case 51, and this convex portion is formed to correspond to the shape of the light-transmitting sheet 60. The sheet holding portion 70 has fixing holes 73.

The seat holder 70 is provided at a position corresponding to each fixing pin 84 and has fixing holes 73 through which the fixing pins 84 pass. As shown in Figure 4, the seat holder 70 has recesses 73a around the fixing holes 73. The recesses 73a are the locations where the tips 84a of the fixing pins 84, which have been melted for welding, join.

The fixing holes 73 are formed at locations corresponding to the fixing pins 84. In this disclosure, the fixing holes 73 are formed in 16 locations. A total of three or more fixing holes 73 must be formed, including reference fixing holes and elongated fixing holes.

The reference fixing hole has approximately the same diameter as the fixing pin 84 and serves as a reference for positioning the fixing frame 80 relative to the upper case 51. It is preferable that the reference fixing hole has a diameter large enough to allow the fixing pin 84 to be inserted while still allowing positioning.

Two or more elongated fixing holes are formed, each elongated in the direction toward the reference fixing hole. This allows the position to be determined by the reference fixing hole, but also prevents undue stress from being generated, reducing the risk of breakage even if the fixing frame 80 expands or contracts when heated or cooled.

The fixing holes 73 other than the reference fixing holes and the elongated fixing holes may be fixed by welding the fixing pins 84, and may have a diameter larger than that of the fixing pins 84 so as not to interfere with the expansion or contraction of the fixing frame 80.

When the fixed frame 80 is fixed to the upper case 51, the locking portions 53 temporarily secure the flat translucent sheet 60 to the curved sheet holding portions 70 until the fixed frame 80 is fixed by the fixing holes 73. In other words, when the temporary fastening hooks 86 are temporarily fastened to the locking portions 53, the translucent sheet 60 is temporarily fixed between the fixed frame 80 and the sheet holding portions 70. The locking portions 53 are provided at the points of greatest curvature on each side 76. In other words, the locking portions 53 are provided at points corresponding to the curvature of the translucent sheet 60.

The fixing pins 84 are firmly joined to the sheet holding part 70 by welding after the light-transmitting sheet 60 and the fixing frame 80 are placed on the sheet holding part 70 with the fixing pins 84 passing through the corresponding sheet holes 62 (an example of through holes) and fixing holes 73 of the light-transmitting sheet 60 and the sheet holding part 70. The fixing pins 84 are provided at a total of 16 locations, four on each side 75, 76, and are preferably provided evenly on the sheet holding part 70.
It is desirable that when the fixing pin 84 is fixed to the fixing hole 73, the fixing point is positioned on the internal space 55 side of the device. In the embodiment shown in Patent Document 1, when the fixing pin is welded to the fixing hole, the welding point is welded at a position exposed to the outside. If the fixing point is positioned in such an exposed position, dust and water are likely to enter through this fixing point if the fixation is incomplete for some reason. However, if the fixing pin is covered by the fixing frame 80 and fixed at a position on the internal space 55 side, it becomes easy to configure a dustproof and waterproof structure on the external side of the device, thereby achieving improved dustproofness.

The translucent sheet 60 has sheet holes 62 that correspond to the fixing pins 84.

The sheet holes 62 are provided at positions corresponding to the fixing pins 84, and each fixing pin 84 passes through them. The sheet holes 62 are formed to have a certain gap relative to the fixing pins 84. This reduces interference between the fixing pins 84 and the light-transmitting sheet 60 (the periphery of the sheet holes 62) due to vibration or thermal expansion, and reduces distortion of the light-transmitting sheet 60 caused by the fixing pins 84.

The fixed frame 80 is made of a synthetic resin material with light-blocking properties and a resin with a lower melting point than the upper case 51 (for example, black polypropylene). The fixed frame 80 covers the sheet periphery 60c and secures the light-transmitting sheet 60 to the sheet holding unit 70. The fixed frame 80 also functions to shield the sheet holding unit 70 from viewers. The fixed frame 80 has a main body 81, outer edge legs 82, inner edge legs 83, and a first wall 85.

The main body 81 has a frame shape that corresponds to the curved shape of the sheet holding portion 70.

The outer edge leg 82 protrudes and extends substantially perpendicularly from the outer edge 81c (outer edge 81c side) of the main body 81 toward the back surface 81b of the main body 81 (extending substantially in the -Z direction). The outer edge leg 82 forms a single convex portion relative to the back surface 81b. The outer edge leg 82 protrudes downward along the Z axis beyond the convex surface 70a of the sheet holding portion 70, and forms a labyrinth structure together with the first wall 85 and second wall 73b to provide dust and water protection. As a result, the outer edge leg 82 can reduce the amount of dust and moisture that enters the interior of the HUD 1 through the opening 56.

The inner edge leg 83 extends from the inner edge 81d of the main body 81, protruding approximately perpendicularly to the back surface 81b of the main body 81 (extending approximately in the -Z direction). The inner edge leg 83 forms a single convex portion on the back surface 81b. The inner edge leg 83 is in continuous line contact with the sheet peripheral edge 60c (the sheet peripheral edge 60c on the surface 60a of the translucent sheet 60), making it more dustproof and waterproof than the inner edge leg 83 is against the outer edge 81c. As a result, the inner edge leg 83, like the outer edge leg 82, can reduce the intrusion of dust and moisture into the HUD1 through the opening 56. Furthermore, the inner edge leg 83 is located closer to the outer edge 81c than the inner edge 81d of the main body 81. As a result, even if the HUD 1 vibrates due to vehicle vibrations and resin shavings are generated due to friction between the inner edge legs 83 and the light-transmitting sheet 60, the impact of the shavings on the inside of the sheet periphery 60c, which is the visible range of the light-transmitting sheet 60, can be reduced.

The first wall 85 is a protrusion that surrounds the periphery of the sheet hole 62. The first wall 85 makes line contact with the light-transmitting sheet 60 so as to surround the periphery of the sheet hole 62, thereby preventing dust and water from entering through the opening 56. The second wall 73b is inserted through the sheet hole 62 and forms a wall that is higher than the light-transmitting sheet 60. The first wall 85, which contacts the light-transmitting sheet 60 from above, and the second wall 73b, which protrudes from below relative to the light-transmitting sheet 60, separate the fixing hole 73 from the outside, preventing dust and water from entering through the fixing hole 73.

The temporary fastening hook 86 is a hook that engages with the engaging portion 53. During assembly, after the fixed frame 80 and translucent sheet 60 are placed on the sheet holding portion 70, the temporary fastening hook 86 temporarily fastens the fixed frame 80 and translucent sheet 60 to prevent the fixed frame 80 from shifting position or falling off relative to the upper case 51 until the fixing pins 84 are welded to the fixing holes 73.

Next, we will explain the procedure for attaching the translucent sheet 60 to the upper case 51.

First, the light-transmitting sheet 60 is attached so that the sheet holes 62 fit into the fixing pins 84 of the fixing frame 80. Workability can be improved if the fixing pins 84 have a temporary fastening mechanism to temporarily fasten the light-transmitting sheet 60 to the fixing frame 80. The temporary fastening mechanism is preferably a push-pull type structure that engages the fixing pins 84 at locations corresponding to the non-curved edges 75, so that once the light-transmitting sheet 60 has passed through the sheet holes 62, it will not fall off. This temporarily fastens the light-transmitting sheet 60 to the sheet holder 70 while maintaining its curved shape.

Afterwards, or at approximately the same time, the light-transmitting sheet 60, attached to the fixing frame 80, is placed on the sheet holding portion 70 of the upper case 51. At the same time, the fixing pins 84 are inserted into the fixing holes 73 of the sheet holding portion 70 and penetrate the upper case 51. As a result, the light-transmitting sheet 60 is sandwiched between the upper case 51 and the fixing frame 80.

At this time, the temporary fastening hooks 86 are engaged with the engaging portions 53. This engagement temporarily secures the fixed frame 80 and the light-transmitting sheet 60 without them falling off the upper case 51. The temporary fastening hooks 86 and engaging portions 53 are positioned corresponding to the curved portions of the light-transmitting sheet 60 so that they fit into the concave edges of the upper case 51, thereby efficiently suppressing the force that attempts to restore the sheet from its curved position.

Then, the tip 84a of the fixing pin 84 protruding from the fixing hole 73 is welded to the recess 73a of the sheet holding part 70, joining the fixing pin 84 and the sheet holding part 70. At this time, because the upper case 51 is made of a material with a higher melting point than the material of the fixing pin 84, the upper case 51 does not melt along with the fixing pin 84 during welding. By being fixed to the fixing pin 84, the upper case 51 sandwiches and fixes the light-transmitting sheet 60 together with the fixing frame 80. This ensures that the light-transmitting sheet 60 is securely held on the upper case 51 so that it will not fall off from the upper case 51 when a load is applied, for example, in the direction toward the inside of the HUD 1 (-Z direction).

This type of HUD 1 can improve the dustproofness of the light-transmitting sheet 60. In other words, if the fixing pins are exposed to the outside of the device, dust and water from the outside can easily enter the device. In contrast, in the HUD 1 of this embodiment, the fixing pins 84 on the fixing frame 80 pass through the fixing holes 73 in the upper case 51 (sheet holding portion 70) and are welded inside the device, making it easier to configure the fixing frame 80 and upper case 51 with a structure that further improves dustproofness and waterproofness, thereby achieving improved dustproofness.

While several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments may be embodied in a variety of other forms, and various omissions, substitutions, and modifications may be made without departing from the spirit of the invention. These embodiments and their variations are within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as set forth in the claims.

For example, the fixed frame 80 may be fixed by a method other than welding. For example, a packing such as an O-ring may be press-fitted into the tip 84a of the fixing pin 84 protruding from the fixing hole 73, and the fixed frame 80 may be fixed by sandwiching the fixed frame 80 between the packing and the upper case 51 (seat holding portion 70).

1. Head-up display (HUD)
20 Display device 21 Light source 22 Liquid crystal display element 23 Wiring board 30 Plane mirror 40 Concave mirror 50 Case 51 Upper case 51a Surface 52 Lower case 53 Locking portion 55 Internal space 56 Opening 56c Opening periphery 60 Light-transmitting sheet 60a Surface 60c Sheet periphery 62 Sheet hole (an example of a through hole)
62a Gap 63 Temporary fixing notch 70 Sheet holding portion 70a Convex surface 73 Fixing hole 73a Recess 73b Second wall 80 Fixing frame 81 Main body 81b Back surface 81c Outer edge 81d Inner edge 82 Outer edge side leg 83 Inner edge side leg 84 Fixing pin 85 First wall 86 Temporary fixing hook L Indicator light

Claims (5)

a display device that outputs display light;
a light-transmitting sheet having a light-transmitting property and a sheet periphery;
a case for accommodating the display device, the case including: an opening covered with the light-transmitting sheet and for emitting the display light to the outside through the light-transmitting sheet; and a sheet holding portion located on a periphery of the opening and holding a periphery of the sheet;
a fixing frame that covers the periphery of the sheet and fixes the light-transmitting sheet to the sheet holding portion,
The fixing frame has a fixing pin,
the light-transmitting sheet has a through-hole through which the fixing pin passes,
the sheet holding portion fixes the light-transmitting sheet between the fixing frame and the fixing pin by fixing the fixing pin to a fixing hole provided in the case;
The fixing frame has a first wall that abuts against the periphery of the through hole . The head-up display according to claim 1 , wherein the sheet holding portion has a second wall that is inserted into the through-hole and has a height higher than that of the light-transmitting sheet . a display device that outputs display light;
a light-transmitting sheet having a light-transmitting property and a sheet periphery;
a case for accommodating the display device, the case including: an opening covered with the light-transmitting sheet and for emitting the display light to the outside through the light-transmitting sheet; and a sheet holding portion located on a periphery of the opening and holding a periphery of the sheet;
a fixing frame that covers the periphery of the sheet and fixes the light-transmitting sheet to the sheet holding portion,
The fixing frame has a fixing pin,
the light-transmitting sheet has a through-hole through which the fixing pin passes,
the sheet holding portion fixes the light-transmitting sheet between the fixing frame and the fixing pin by fixing the fixing pin to a fixing hole provided in the case;
The sheet holding portion has a second wall that is inserted into the through hole and is higher than the light-transmitting sheet.
Head-up display. The fixing frame has a first wall that abuts against the periphery of the through hole.
The head-up display according to claim 3 . a display device that outputs display light;
a light-transmitting sheet having a light-transmitting property and a sheet periphery;
a case for accommodating the display device, the case including: an opening covered with the light-transmitting sheet and for emitting the display light to the outside through the light-transmitting sheet; and a sheet holding portion located on a periphery of the opening and holding a periphery of the sheet;
a fixing frame that covers the periphery of the sheet and fixes the light-transmitting sheet to the sheet holding portion,
The fixing frame has a fixing pin,
the light-transmitting sheet has a through-hole through which the fixing pin passes,
the sheet holding portion fixes the light-transmitting sheet between the fixing frame and the fixing pin by fixing the fixing pin to a fixing hole provided in the case;
the light-transmitting sheet is fixed in a curved state,
The fixing frame is provided at a portion of the light-transmitting sheet that has the largest curvature among portions corresponding to the curvature of the light-transmitting sheet, and has a locking portion that is locked to the case.
Head-up display.