JP6787010B2 - Mirror unit of head-up display device - Google Patents

Description

The present invention relates to a mirror unit of a head-up display device, and is suitable as, for example, a mirror unit that projects a display image onto a front windshield of a vehicle.

Conventionally, as a display device using a mirror unit having a reflection mirror that reflects display light, there is a head-up display device, which is disclosed in, for example, Patent Document 1. The head-up display described in Patent Document 1 is attached to the inside of an instrument panel (hereinafter referred to as an instrument panel) of a vehicle, and projects the display light emitted by the display device onto the front windshield (windshield) of the vehicle. A virtual image is displayed to the user (driver) of the vehicle.

The above-mentioned display device includes a light source, a display that emits display light when the light source emits light, a mirror unit for reflecting the display light emitted by this display toward the front windshield, and a light source, a display, and a mirror. It is mainly composed of a storage unit that houses the unit and a housing made of synthetic resin that has a translucent portion that transmits the display light reflected by the mirror unit, and the display light reflected by the reflected mirror of the mirror unit. A virtual image is displayed by projecting onto the front windshield through the translucent part.

Japanese Unexamined Patent Publication No. 9-109732

These head-up display devices are mounted on a vehicle, and the temperature changes are large not only due to changes in the temperature environment outside the vehicle but also due to high temperature due to sunlight irradiation. The reflective mirror is adhered and held in a predetermined position on the holder, but since the linear expansion coefficient between the reflective mirror and the holder is not the same, the amount of deformation (expansion or contraction) between the reflective mirror and the holder due to this temperature change It makes a difference.

In particular, when the reflection mirror is large or the material (deformation rate) is different between the reflection mirror and the holder, the difference in the amount of deformation becomes large, and when a large vibration due to the running of the vehicle is added to this, the reflection mirror is large. There is a risk that the holder will not be able to hold the reflective mirror sufficiently due to peeling of the adhesive. Therefore, a structure capable of maintaining the holding state of the reflection mirror even when thermal deformation occurs has been desired.

Therefore, an object of the present invention is to focus on the above-mentioned problems and to provide a reflection mirror unit of a head-up display device capable of maintaining a holding state of the reflection mirror even when thermal deformation occurs.

The mirror unit of the head-up display device of the present invention
A reflective mirror with a reflective surface on a plate-shaped base material,
A holder that rotatably holds this reflective mirror,
An adhesive member for fixing the reflection mirror to the holder is provided.
The holder is provided with a plurality of convex bases on which the adhesive member is placed .
These base portion than the distance between said platform portions provided inside the <br/> provided that towards the spacing of said platform portions provided outside is separated so that a large distance It is a feature.

Further, the adhesive member is made of a moisture-curable resin adhesive provided between the base portion and the reflection mirror.
The mirror unit of the head-up display device according to claim 1, wherein a plurality of the pedestals are formed in a line shape substantially perpendicular to the longitudinal direction of the reflection mirror.

Further, the base portion is characterized in that a plurality of the base portions are formed in a contrasting arc shape from the center of the reflection mirror.

Further, the reflection mirror and the holder are made of different materials.

The present invention is a mirror unit of a head-up display device capable of maintaining a holding state of a reflective mirror even when thermal deformation occurs.

The schematic diagram which the head-up display device by embodiment of this invention was mounted on a vehicle. Sectional drawing of the head-up display apparatus by the same embodiment. The figure which shows the mirror unit by the same embodiment. The figure which shows the holder by the same embodiment. FIG. 6 is a cross-sectional view (RR cross-sectional view) showing a main part of the mirror unit using the holder of FIG. The figure which shows the modification of the holder of the same embodiment. The figure which shows the modification of the holder of the same embodiment. FIG. 7 is a cross-sectional view (SS cross-sectional view) showing a main part of the mirror unit using the holder of FIG. 7.

Hereinafter, an embodiment in which the mirror unit of the present invention is applied to a head-up display for a vehicle will be described with reference to the drawings.

As shown in FIG. 1, the head-up display device A is a display unit provided inside the instrument panel (instrument panel) B of the vehicle B, and the head-up display device (hereinafter, also referred to as a HUD device) A projects. The display light L to be displayed is reflected by the front windshield (windshield) D of the vehicle B, which is a projection member, in the direction of the driver (user) E of the vehicle B, and the virtual image V is displayed. In other words, the HUD device A emits the display light L and emits (projects) it to the front windshield D, so that the driver E can visually recognize the display image (virtual image V) obtained by this emission. As a result, the driver E can observe the virtual image V displayed in front of the driver's seat by superimposing it on the landscape.

Further, as shown in FIG. 2, the HUD device A is mainly composed of a liquid crystal display 1, a first reflector 2, a second reflector 3 which is a mirror unit, and a housing 4.

The liquid crystal display 1 is arranged so as to face the illumination direction of the light source 11 and the light source 11 made of a light emitting diode mounted on a wiring board so as to transmit the illumination light from the light source 11 to form the display light L. A TFT type liquid crystal display element 12 is provided. This means that a light source 11 is provided behind the liquid crystal display element 12 (opposite to the emission of the display light L), and the liquid crystal display element 12 transmits the light emitted from the light source 11 and projects and displays predetermined information. It means that.

The liquid crystal display 1 is provided in the housing 4 so that the surface of the display light L on the exit side faces the cold mirror described later, which is the first reflector 2, and the optical axis of the display light L is the cold mirror. It is fixed and held at a position and orientation that intersects with.

Further, the liquid crystal display element 12 forms an image of predetermined information (for example, vehicle information such as the speed of the vehicle B, the engine speed, and route guidance) with numerical values, characters, marks, or the like by an element drive circuit (not shown). The liquid crystal display 1 uses the illumination light from the light source 11 to output the display light L composed of light in the visible wavelength range. For example, a light source 11 that emits white light can be applied, and colored (red, green, etc.) display light L can be formed through a color filter provided in the liquid crystal display element 12. The predetermined information formed by the liquid crystal display element 12 is not limited to vehicle information such as the speed of the vehicle B and the engine speed, and any display form such as time, moving image, and lane guidance can be adopted.

The first reflector 2 has a cold mirror 21 and a fixing member 22 for mounting and fixing the cold mirror 21 by using a predetermined fixing means. The cold mirror 21 is composed of a substantially rectangular glass substrate and a reflection layer 21a formed on one surface of the glass substrate (the surface facing the concave mirror described later, which is the second reflector 3). The reflective layer 21a is made of a multi-layer interference film having a different film thickness, and is formed by a method such as thin film deposition. Further, the cold mirror 21 is provided in an inclined state at a position where the display light L emitted by the liquid crystal display 1 (liquid crystal display element 12) is reflected toward the second reflector 3 (the concave mirror).

The cold mirror 21 reflects light in the visible wavelength range (450 to 750 nm) including the emission wavelength range of the liquid crystal display 1 with high reflectance, and reflects light other than the visible wavelength range with low reflectance. Is preferable. In this case, the cold mirror 21 is applied to reflect light (infrared rays or heat rays of sunlight) in a wavelength region other than the visible wavelength region with a low reflectance. The light that is not reflected by the reflective layer 21a is configured to pass through the cold mirror 21. The fixing member 22 is made of a synthetic resin material and is fixed to the housing 4.

As shown in FIG. 3, the second reflector 3 which is a mirror unit includes a concave mirror 31 which is a reflection mirror provided in the housing 4 and the concave mirror 31 in order to reflect the display light L from the cold mirror 21. A holder 32 for holding the holder 32 and a driving means 33 for rotating the holder 32 on which the concave mirror 31 is mounted and adjusting the inclination angle of the concave mirror 31 are provided. The concave mirror 31 is adhesively held to the holder 32 by using an adhesive member 34 (shown in FIG. 5).

The concave mirror 31 is made of a plate-shaped base material 31a made of a synthetic resin (for example, polycarbonate) and a metal such as aluminum formed by vapor deposition on the front surface portion of the base material 31a (that is, the surface facing the reflection layer 21a of the cold mirror 21). A reflective film 31b is provided, and the reflective surface formed by the reflective film 31b is a concave curved surface (concave surface) having a predetermined curvature. In this case, the base material 31a is molded by injection molding. It is also conceivable to substitute glass or a metal plate as the base material 31a.

The reflective film 31b formed as the concave surface serves as a light reflecting surface for reflecting the display light L from the cold mirror 21 toward the front windshield D side. The concave mirror 31 is provided in an inclined state at a position where the reflective surface formed by the reflective film 31b faces the cold mirror 21 and the upper front windshield D and faces the translucent cover described later in the housing 4.

Further, the concave mirror 31 enlarges the display light L from the cold mirror 21 and reflects it toward the translucent cover (front windshield D of the vehicle B). This means that the concave mirror 31 magnifies the display light L reflected by the cold mirror 21 and projects the magnified display light L onto the front windshield D through the translucent cover. Further, in this case, the reflecting surface of the concave mirror 31 has a curved surface shape that can be corrected so as to reduce the distortion of the virtual image V according to the curved surface shape of the front windshield D.

Further, a convex convex portion 31c (shown in FIG. 5) is formed on the surface of the concave mirror 31 facing the holder 32 (the surface opposite to the reflective surface), and is used as a spacer between the concave mirror 31 and the holder 32. Acts as a member of. The convex portion 31c can be formed on the holder 32 side to replace the convex portion 31c.

The holder 32 is for holding the concave mirror 31 in a predetermined position, and a metal material close to the linear expansion coefficient (coefficient of thermal expansion) of the housing 4, for example, aluminum die casting can be applied.

The holder 32 is provided on the back surface side (opposite side of the reflecting surface) of the concave mirror 31, and as shown in FIGS. 4 and 5, a shaft portion 32a, a flat portion 32b, and a base portion 32c are formed.

The shaft portion 32a pivotally supports the rotation of the concave mirror 31 by the driving means 33, and is pivotally supported by the holding portion formed in the housing 4. The shaft portion 32a may be pivotally supported by the housing 4 via a ball bearing.

The flat portion 32b is provided at a position facing the convex portion 31c of the concave mirror 31, and comes into surface contact with the convex portion 31c. The convex portions 31c are provided at three locations along both ends of the concave mirror 31, and have an effect of making the clearance with the holder 32 constant. The flat portion 32b is prepared to be flat slightly wider than the contact position with the convex portion 31c, and can retain its role as a spacer even if the holder 32 and the concave mirror 31 are relatively misaligned.

A plurality of base portions 32c are provided facing the concave mirror 31 in a raised convex shape, leaving a clearance between the base portion 32c and the concave mirror 31 so that the adhesive member 34 is provided. The holder 32 can hold the concave mirror 31 in a holding state by curing the adhesive member 34 provided between the base portion 32c and the concave mirror 31. Further, when the adhesive member 34 is excessively applied, the extra adhesive member 34 flows in the space between the base portions 32c, and it becomes difficult to participate in the adhesion with the concave mirror 31. Therefore, the adhesive strength with the concave mirror 31 can be easily controlled by the shape and arrangement of the base portion 32c.

In this case, a plurality of base portions 32c are provided at intervals in a line shape substantially perpendicular to the longitudinal direction X of the concave mirror 31. Further, the base portion 32c is formed in a radial arc shape from the position Q facing the substantially center of the concave mirror 31. Therefore, the base portion 32c serves as an adhesive surface with the concave mirror 31, and the concave portion between the base portions 32c has weak adhesive strength or does not have adhesive strength. That is, regarding the adhesive strength of the concave mirror 31, the strength in the longitudinal direction X is smaller than that in the direction Y perpendicular to the longitudinal direction X.

The concave mirror 31 formed in a plate shape having substantially the same thickness has a slightly larger amount of thermal deformation on the longitudinal direction X side than the amount of deformation in the direction Y perpendicular to the longitudinal direction X, but the adhesion in the longitudinal direction X By weakening the strength, the bonded state can be maintained even if there is a relative positional deviation between the concave mirror 31 and the holder 32. That is, by providing the recessed portion between the base portions 32c, it is possible to prevent the adhesive member 34 from being pulled and peeled off in the longitudinal direction X due to deformation (relative positional deviation) of the concave mirror 31 and the holder 32. The adhesive holding force of the concave mirror 31 can be maintained in a direction in which the amount of deformation of the concave mirror 31 is small (a direction Y substantially perpendicular to the longitudinal direction X).

Further, among the plurality of pedestals 32c, the pedestal 32c near the position Q facing the substantially center of the concave mirror 31, that is, the pedestal 32c provided on the inner side has an area per one more than each of the outer pedestals 32c. Is made smaller. As a result, in holding the concave mirror 31 by the holder 32, the adhesive strength near the center of the concave mirror 31 can be set stronger than the adhesive strength on the outside.

Therefore, even if thermal deformation occurs, the amount of misalignment near the center of the concave mirror 31 can be reduced. Therefore, the degree of distortion of the display on the reflecting surface that reflects the display light L near the center of the image, which is the main part of the HUD device A, can be reduced, and the deterioration of the display quality due to the change in the environmental temperature can be suppressed.

The center of the concave mirror 31 may be an optical center used as a display area, or the center of gravity may be the center, and the above effects can be obtained in either case.

Further, as shown in FIG. 4, the distance between the bases 32c (recessed portion) is set to be larger on the outside than on the inside. As a result, in holding the concave mirror 31 by the holder 32, the adhesive strength near the center of the concave mirror 31 can be set stronger than the adhesive strength on the outside, and the above-mentioned effect can be further enhanced.

A moisture-curable resin-based adhesive can be applied to the adhesive member 34, which is applied to the base portion 32c of the holder 32 in a viscous state, and when the concave mirror 31 is assembled, the adhesive member 34 is deformed while being crushed. By curing with, it becomes an adhesive state. As the adhesive member 34, the double-sided adhesive sheet can be replaced and applied by being attached according to the shape of the base portion 32c.

The driving means 33 can change the angle of the concave mirror 31 by utilizing the stepping motor 33a that generates a driving force by energization and the rotation of the stepping motor 33a. In this case, the drive means 33 moves a lead screw type screw formed on the rotation shaft of the stepping motor 33a fixed to the housing 4 in a linear direction, and the concave mirror 31 or the arm portion 31d extending from the holder 32 is screwed. The concave mirror 31 is configured to rotate around the shaft portion 32a by pushing and pulling. The drive means 33 can be applied not only to the lead screw type but also to a rack and pinion type or a configuration in which a stepping motor rotates the shaft portion 32a via a gear or the like.

The housing 4 is formed in a substantially box shape by, for example, combining molded parts of a black light-shielding synthetic resin material and a metal member (aluminum die-cast), and the liquid crystal display 1 and the first 1. Holds and accommodates the second reflectors 2 and 3. These housed parts are held by a holding body 41 made of a metal material.

Further, in the housing 4, an upper portion (front windshield D side) of the arrangement position of the concave mirror 31 in the second reflector 3 is opened, and a translucent cover 42 which is a translucent portion is arranged so as to close the opening. Being done. The translucent cover 42 is made of a translucent synthetic resin material (for example, acrylic resin), is formed in a curved shape (curved shape), and is transmitted (passed) by the display light L reflected by the concave mirror 31. It has a function as a transparent member. That is, the display light L reflected by the concave mirror 31 is projected onto the front windshield D through the translucent cover 42 formed in the housing 4, whereby the virtual image V is displayed to the driver E. ..

The second reflector 3 of the HUD device A has a concave mirror 31 having a reflective surface on a plate-shaped base material, a holder 32 for rotatably holding the concave mirror 31, and an adhesion for fixing the concave mirror 31 to the holder 32. A member 34 is provided, and a plurality of convex base portions 32c on which the adhesive member 34 is placed are provided on the holder 32 at a distance.

Therefore, the area related to the adhesion between the holder 32 and the concave mirror 31 by the adhesive member 34 can be controlled, and by changing the adhesive strength depending on the direction, the adhesive member 34 is hard to be peeled off even if deformation due to a temperature change occurs. Therefore, the structure is such that the holding state of the concave mirror 31 by the holder 32 can be maintained even in an in-vehicle environment where the temperature change is large and vibration or the like occurs.

Further, the adhesive member 34 is made of a moisture-curable resin adhesive provided between the base portion 32c of the holder 32 and the concave mirror 31, and the base portion 32c has a line shape substantially perpendicular to the longitudinal direction X of the concave mirror 31. By forming a plurality of them, the adhesive strength in the longitudinal direction X, which has a large amount of deformation, is weakened, and an adhesive structure that is hard to peel off can be formed.

Further, the base portion 32c is formed in a plurality of contrasting arcuate shapes from the center of the concave mirror 31, so that it has an adhesive structure that easily corresponds to the thermal deformation direction of the concave mirror 31.

Further, the concave mirror 31 and the holder 32 are made of different materials, and the above-mentioned effects can be obtained even when the linear expansion coefficients are different.

Next, a modified example of the second reflecting portion 3 serving as the mirror unit will be described with reference to FIGS. 6 to 8. It should be noted that FIGS. 6 to 8 show modified examples of FIGS. 4 and 5, and the same reference numerals are given for similar parts, and detailed description thereof will be omitted.

In FIG. 6, instead of the base portion 32c having different areas of the above-described embodiment, a plurality of base portions 320c having the same width and area and forming an arc shape are arranged at substantially the same intervals. Even in this case, as in the above-described embodiment, the adhesive strength of the concave mirror 31 is smaller in the longitudinal direction X than in the direction Y perpendicular to the longitudinal direction X. By weakening the adhesive strength in the longitudinal direction X, the adhesive state can be maintained even if there is a relative positional deviation between the concave mirror 31 and the holder 320.

As shown in FIG. 7, even when the base portion 321c having the same area or linearly formed with the same width is applied, by changing the interval of each base portion 321c, the above-mentioned effect, that is, Even if thermal deformation occurs, there is an effect that the amount of misalignment near the center of the concave mirror 31 can be reduced. Further, even with the shape of the base portion 321c shown in FIG. 7, the adhesive strength in the longitudinal direction X can be weaker than the adhesive strength in the direction Y substantially perpendicular to the longitudinal direction X, as in the configurations of FIGS. The adhesive member 34 has a structure that is difficult to peel off due to thermal deformation.

FIG. 8 is a cross-sectional view of the mirror unit using the holder 321 of FIG. 7. The pedestal portion 321c near the position Q facing the substantially center of the concave mirror 31, that is, the pedestal portion 321c provided on the inside is each of the outer pedestals. The distance from the facing surface of the concave mirror 31 is smaller than that of the portion 321c. As a result, the thickness of the adhesive member 34 is set to be different between the inside and the outside, and the adhesive strength near the center of the concave mirror 31 can be set stronger than the adhesive strength on the outside when the concave mirror 31 is held by the holder 321.

Therefore, even if thermal deformation occurs, the amount of misalignment near the center of the concave mirror 31 can be reduced. Therefore, the degree of distortion of the display on the reflecting surface that reflects the display light L near the center of the image, which is the main part of the HUD device A, can be reduced, and the deterioration of the display quality due to the change in the environmental temperature can be suppressed.

Further, as shown in FIG. 8, a stop member 35 for holding the concave mirror 31 can be provided. The stopping member 35 is provided at two places so as to hold the vicinity of the side (end) facing the longitudinal direction X of the concave mirror 31. Further, the stop member 35 is in contact with the reflective surface side of the concave mirror 31 via the elastically deformable cushioning material 36, and can absorb the dimensional change due to thermal deformation to maintain the holding state of the concave mirror 31. The stopper 35 is fixed to the holder 32 by screwing (not shown) with the concave mirror 31 interposed therebetween.

Further, in this case, the stop member 35 is formed by pressing a metal plate material and is provided so as to be elastically deformable. The concave mirror 31 can be sandwiched between the holder 32 and the concave mirror 31 while applying this elastic force as a pressing force to the concave mirror 31. It is also possible to form the stop member 35 by molding the synthetic resin material.

The pressing force can also be urged by the cushioning material 36. Further, even if the relative position change between the stop member 35 and the concave mirror 31 occurs during thermal deformation, the concave mirror 31 is reduced in influence on the reflecting surface due to the deformation or slippage of the cushioning material 36. Positioning and holding state can be maintained. As the cushioning material 36, for example, a member such as urethane foam material or synthetic rubber can be applied.

Although the head-up display device of the present invention has been described by way of example in the configuration of the above-described embodiment, the present invention is not limited to this, and the gist of the present invention can be described in other configurations as well. Of course, various improvements and display changes are possible within the range that does not deviate.

For example, in the above-described embodiment, the liquid crystal display 1 that forms a display image by using the irradiation light of the light source 11 has been described as an example, but the laser light may be scanned and applied as the illumination light. , A projector method using a DMD (Digital Mirror Device) can also be applied, and by combining the above mirror units, the same effect as that of the above-described embodiment can be obtained.

Further, in the above-mentioned cold mirror 21, this can be omitted depending on temperature conditions (heat generation of electronic parts such as a light source), sunlight irradiation conditions, and the like. For example, the display light from the liquid crystal display 1 can be used. Even in the configuration of projecting onto the front windshield D via reflection by the concave mirror 31, the same effect as that of the above-described embodiment can be obtained. Further, the holder 32 can be applied even if it has a substantially flat plate shape having the above-mentioned base portion, and is easy to process.

The present invention relates to a mirror unit, for example, mounted on a moving body equipped with an automobile, a motorcycle, or an agricultural machine or a construction machine, and is suitable as an in-vehicle display device for time, vehicle information, road information such as turn-by-turn display, and the like. is there.

1 Liquid crystal display 2 1st reflector 3 2nd reflector (mirror unit)
31 Concave mirror (reflection mirror)
32, 320, 321 Holders 32c, 320c, 321c Base 34 Adhesive member 4 Housing A HUD (head-up display) device

Claims (4)

A reflective mirror with a reflective surface on a plate-shaped base material,
A holder that rotatably holds this reflective mirror,
An adhesive member for fixing the reflection mirror to the holder is provided.
The holder is provided with a plurality of convex bases on which the adhesive member is placed .
These base portion than the distance between said platform portions provided inside the <br/> provided that towards the spacing of said platform portions provided outside is separated so that a large distance The featured mirror unit of the head-up display device. The adhesive member is made of a moisture-curable resin adhesive provided between the base and the reflection mirror.
The mirror unit of the head-up display device according to claim 1, wherein a plurality of the pedestals are formed in a line shape substantially perpendicular to the longitudinal direction of the reflection mirror. The mirror unit of the head-up display device according to claim 1, wherein a plurality of the base portions are formed in a contrasting arc shape from the center of the reflection mirror. The mirror unit of the head-up display device according to any one of claims 1 to 3, wherein the reflection mirror and the holder are made of different materials.

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