JP2018055039A - Mirror unit for head-up display devices - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reflective mirror unit for head-up display devices, which allows a reflective mirror to be held steadily even in the presence of thermal deformation.SOLUTION: A reflective mirror unit for head-up display devices comprises a concave mirror 31 consisting of a tabular base material with a reflective surface, a holder 32 for rotatably holding the concave mirror 31, and adhesive members 34 for fixing the concave mirror 31 onto the holder 32. The holder 32 has a plurality of convex base sections 32c that are formed at a distance from each other to mount the adhesive members 34. The base sections 32c have counter surfaces facing the concave mirror 31 and are formed such that the counter surfaces of those located on the inner side have larger area than those located on the outer side.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a mirror unit of a head-up display device, and is suitable, for example, as a mirror unit that projects a display image on 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 Patent Document 1, for example. The head-up display described in Patent Document 1 is attached to the interior of an instrument panel (hereinafter referred to as instrument panel) of a vehicle, and projects display light emitted from the display device onto a front windshield (windshield) of the vehicle. A virtual image is displayed to the vehicle user (driver).

  The display device described above includes a light source, a display that emits display light as the light source emits light, a mirror unit that reflects the display light emitted from the display to the front windshield, a light source, a display, and a mirror. And a housing made of a synthetic resin having a light-transmitting portion that transmits the display light reflected by the mirror unit, and the display light reflected by the reflecting mirror of the mirror unit. A virtual image is displayed by projecting onto the front windshield through the translucent part.

JP-A-9-109732

  These head-up display devices are mounted on a vehicle and have a large temperature change such as not only a change in temperature environment outside the vehicle but also a high temperature due to sunlight irradiation. Although the reflection mirror is bonded and held at a predetermined position of the holder, since the linear expansion coefficient of the reflection mirror and the holder is not the same, the deformation amount (expansion or contraction amount) of the reflection mirror and the holder is caused by this temperature change. There will be a difference.

  In particular, when the reflecting mirror is large or the material (deformation rate) is different between the reflecting mirror and the holder, the difference in the amount of deformation becomes large. There is a possibility that the holder cannot sufficiently hold the reflecting mirror due to peeling of the adhesive. For this reason, there has been a demand for a structure that can maintain the holding state of the reflecting mirror even when thermal deformation occurs.

  Accordingly, an object of the present invention is to provide a reflection mirror unit of a head-up display device capable of maintaining the holding state of the reflection mirror even when thermal deformation occurs, paying attention to the above-described problems.

The mirror unit of the head-up display device of the present invention is:
A reflective mirror having a reflective surface on a plate-like substrate;
A holder for rotatably holding the reflecting mirror;
An adhesive member for fixing the reflection mirror to the holder,
The holder is provided with a plurality of convex pedestals on which the adhesive member is placed, spaced apart from each other,
The mirror unit of the head-up display device, wherein the base portion is formed such that, on the opposing surface of the reflecting mirror, the inner opposing surface has a larger area than the outer opposing surface.

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 base portions are formed in a line shape substantially perpendicular to a longitudinal direction of the reflection mirror.

2. The mirror unit of the head-up display device according to claim 1, wherein a plurality of the base portions are formed in a circular arc shape contrasting with a 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 formed of different materials.

  The present invention provides a mirror unit of a head-up display device that can maintain the holding state of the reflecting mirror even when thermal deformation occurs.

1 is a schematic view of a head-up display device according to an embodiment of the present invention mounted on a vehicle. Sectional drawing of the head-up display apparatus by the embodiment. The figure which shows the mirror unit by the embodiment. The figure which shows the holder by the embodiment. Sectional drawing (RR sectional drawing) which shows the principal part of the mirror unit using the holder of FIG. The figure which shows the modification of the holder of the embodiment. Sectional drawing (SS sectional drawing) which shows the principal part of the mirror unit using the holder of FIG. The figure which shows the modification of the holder of the embodiment.

  Hereinafter, an embodiment in which a 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 an instrument panel (instrument panel) B of a vehicle B, and the head-up display device (hereinafter also referred to as HUD device) A projects. The display light L to be reflected is reflected in the direction of the driver (user) E of the vehicle B by the front windshield (windshield) D of the vehicle B which is a projection member, and the virtual image V is displayed. In other words, the HUD device A emits the display light L, emits (projects) it to the front windshield D, and causes the driver E to visually recognize the display image (virtual image V) obtained by the emission. As a result, the driver E can observe the virtual image V displayed in front of the driver's seat with the scenery superimposed.

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

  The liquid crystal display 1 is disposed facing the illumination direction of the light source 11 so as to form a display light L by transmitting illumination light from the light source 11 mounted on a wiring board and a light emitting diode. TFT type liquid crystal display element 12 is provided. This is because 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 projects and displays predetermined information by transmitting light emitted from the light source 11. It means that.

  The liquid crystal display 1 is provided in the housing 4 so that the surface on the emission side of the display light L faces a cold mirror, which will be 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 intersect

  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, and 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 display light L composed of light in the visible wavelength range. For example, a light source 11 that emits white light is applied, and colored (red, green, etc.) display light L can be formed through a color filter provided in the liquid crystal display element 12. Note that 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, but can be any display form such as time, a moving image, and lane guidance.

  The first reflector 2 has a cold mirror 21 and a fixing member 22 for mounting and fixing the cold mirror 21 using a predetermined fixing means. The cold mirror 21 includes a substantially rectangular glass substrate and a reflective layer 21a formed on one surface of the glass substrate (a surface facing a later-described concave mirror that is the second reflector 3). The reflective layer 21a is composed of multilayer interference films having different film thicknesses, and is formed by a method such as vapor deposition. The cold mirror 21 is provided in an inclined state at a position where the display light L emitted from 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 region (450 to 750 nm) including the emission wavelength region of the liquid crystal display 1 with high reflectance, and reflects light outside the visible wavelength region with low reflectance. Is preferred. In this case, a cold mirror 21 that reflects light in the infrared wavelength region other than the visible wavelength region (infrared rays or heat rays of sunlight) with a low reflectance is applied. The light that is not reflected by the reflective layer 21 a 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 that is a mirror unit includes a concave mirror 31 that is a reflection mirror provided in the housing 4 in order to reflect the display light L from the cold mirror 21, and the concave mirror 31. A holder 32 for holding 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 bonded and held to the holder 32 using an adhesive member 34 (shown in FIG. 5).

  The concave mirror 31 is made of a plate-like base material 31a made of a synthetic resin (for example, polycarbonate) and a metal such as aluminum formed on the front surface of the base material 31a (that is, the surface facing the reflective layer 21a of the cold mirror 21). 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 formed by injection molding. In addition, it is also conceivable to apply glass or a metal plate instead of the substrate 31a.

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

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

  Further, a convex portion 31 c (shown in FIG. 5) is formed on the surface of the concave mirror 31 facing the holder 32 (the surface opposite to the reflecting surface), and for the spacer between the concave mirror 31 and the holder 32. Acts as a member. In addition, the convex part 31c can also be formed in the holder 32 side, and can replace it.

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

  The holder 32 is provided on the back side of the concave mirror 31 (on the side opposite to the reflecting surface), 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 32 a supports the rotation of the concave mirror 31 by the driving means 33, and is supported by a holding portion formed on the housing 4. The shaft portion 32a may be 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 is in surface contact with the convex portion 31c. In addition, the convex part 31c is provided in three places according to the both ends of the concave mirror 31, and has the effect | action which makes the clearance with the holder 32 constant. The flat portion 32b is prepared to be slightly flatter than the contact position with the convex portion 31c, and can maintain the role as a spacer even if the holder 32 and the concave mirror 31 are displaced relative to each other.

  The pedestal 32c has a surface facing the concave mirror 31, and leaves a clearance sufficient to provide the adhesive member 34 between the concave mirror 31 and faces the concave mirror 31. Are provided. The holder 32 can bring the concave mirror 31 into a holding state by curing the adhesive member 34 provided between the base portion 32 c and the concave mirror 31. Further, when the adhesive member 34 is applied excessively, the excessive adhesive member 34 flows in the space between the base portions 32 c and is not easily involved 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 32c and the surface of the base 32c facing the concave mirror 31.

  In this case, a plurality of base portions 32 c are provided at intervals in a line shape substantially perpendicular to the longitudinal direction X of the concave mirror 31. Further, the pedestal portion 32 c is formed in a radial arc shape from a position Q facing the substantial center of the concave mirror 31. Therefore, the base part 32c becomes an adhesive surface with the concave mirror 31, and the concave part between the base parts 32c has a weak adhesive strength or no adhesive strength. That is, 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.

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

  Further, among the plurality of base parts 32c, the base part 32c near the position Q facing the substantially center of the concave mirror 31, that is, the base part 32c provided on the inner side, is larger in area per one than the outer base parts 32c. To make it smaller. Thereby, 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 outer adhesive strength.

  For this reason, even if thermal deformation occurs, the amount of displacement in the vicinity of 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 in the vicinity of the center of the image, which is the main part of the HUD device A, can be reduced, and deterioration in display quality due to changes in environmental temperature can be suppressed.

  The center of the concave mirror 31 may be the optical center used as the display area, or the center of gravity may be the center, both of which can obtain the above-described effects.

  Further, as shown in FIG. 4, the distance between the base portions 32c (for the concave portions) is set such that the distance on the outer side is larger than the inner side. Thereby, in holding the concave mirror 31 by the holder 32, the adhesive strength in the vicinity of the center of the concave mirror 31 can be set stronger than the outer adhesive strength, and the above-described effects can be further enhanced.

  The adhesive member 34 can be applied with a moisture-curing resin adhesive, is applied to the base portion 32c of the holder 32 in a viscous state, and is deformed while being crushed by the concave mirror 31 being assembled. It will be in an adhesion state by hardening with. Note that, as the adhesive member 34, a double-sided adhesive sheet can be substituted and applied in accordance with the shape of the base portion 32c.

  The driving means 33 can change the angle of the concave mirror 31 by using a 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 the lead screw type screw formed on the rotating shaft of the stepping motor 33a fixed to the housing 4 in the linear direction, and moves the concave mirror 31 or the arm portion 31d extending from the holder 32 to the screw. The concave mirror 31 is configured to rotate about the shaft portion 32a. The drive means 33 can be applied to a rack and pinion type other than a lead screw 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, for example, in a substantially box shape by combining a molded part of a black light-shielding synthetic resin material or a metal member (aluminum die casting), and the liquid crystal display 1 or the second display is formed in the space 40 that is the internal space. 1. Holds and accommodates the second reflectors 2 and 3. These accommodated parts are held by a holding body 41 made of a metal material.

  The housing 4 has an upper portion (front windshield D side) where the concave mirror 31 is disposed in the second reflector 3 and a translucent cover 42 serving as a translucent portion is disposed so as to close the opening. Being done. The light-transmitting cover 42 is made of a light-transmitting synthetic resin material (for example, acrylic resin), is formed in a curved shape (curved surface shape), and transmits (passes) display light L reflected by the concave mirror 31. It has a function as a permeable 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 on the housing 4, whereby the virtual image V is displayed to the driver E. .

The second reflector 3 of the HUD device A includes a concave mirror 31 having a reflecting surface on a plate-like base material, a holder 32 that rotatably holds the concave mirror 31, and an adhesive that fixes the concave mirror 31 to the holder 32. A member 34, and
The holder 32 is provided with a plurality of convex base portions 32c on which the adhesive member 34 is placed, spaced apart from each other,
The pedestal 32c is formed such that, on the facing surface of the concave mirror 31, the inner facing surface has a larger area than the outer facing surface.

  Accordingly, the area (the area of the opposing surface) related to the adhesion between the holder 32 and the concave mirror 31 by the adhesive member 34 can be controlled, and the adhesive strength is changed inside and outside by this contact area, so that the adhesive member even if deformation due to temperature change occurs. In addition to the structure in which 34 is not easily peeled off, it is possible to prevent the central position of the concave mirror 31 from greatly changing even if there is thermal deformation.

  The adhesive member 34 is made of a moisture curable resin adhesive provided between the base portion 32 c of the holder 32 and the concave mirror 31, and the base portion 32 c has a line shape substantially perpendicular to the longitudinal direction X of the concave mirror 31. By forming a plurality, it is possible to weaken the adhesive strength in the longitudinal direction X with a large amount of deformation and to make the adhesive structure difficult to peel off. For this reason, the structure in which the holding state of the concave mirror 31 by the holder 32 can be maintained even in an in-vehicle environment with a large temperature change and vibration.

  In addition, a plurality of base portions 32 c are formed in an arc shape contrasting from the center of the concave mirror 31, thereby providing an adhesive structure that can easily cope with the thermal deformation direction of the concave mirror 31.

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

  Next, modified examples of the second reflecting portion 3 serving as a mirror unit will be described with reference to FIGS. 6 to 8 show modified examples of FIGS. 4 and 5, and the same portions are denoted by the same reference numerals and detailed description thereof is omitted.

  As shown in FIG. 6, even when the pedestal portions 321c having the same area or the same width and being formed in a straight line are applied, the above-described effect, that is, by changing the interval between the pedestal portions 321c, that is, Even if thermal deformation occurs, there is an effect that the amount of displacement in the vicinity of the center of the concave mirror 31 can be reduced. Further, even in the shape of the base part 321c shown in FIG. 7, the adhesive strength in the longitudinal direction X can be weaker than the adhesive strength in the direction perpendicular to the longitudinal direction X. The member 34 has a structure that does not easily peel off due to thermal deformation.

  FIG. 7 is a cross-sectional view of a mirror unit using the holder 321 of FIG. 6, and the base part 321 c near the position Q facing the substantially center of the concave mirror 31, that is, the base part 321 c provided on the inner side, The distance from the opposing surface of the concave mirror 31 is made smaller than the portion 321c. Thereby, the thickness at which the adhesive member 34 is provided is made different between the inner side and the outer side, and when the concave mirror 31 is held by the holder 321, the adhesive strength near the center of the concave mirror 31 can be set stronger than the outer adhesive strength.

  For this reason, even if thermal deformation occurs, the amount of displacement in the vicinity of 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 in the vicinity of the center of the image, which is the main part of the HUD device A, can be reduced, and deterioration in display quality due to changes in environmental temperature can be suppressed.

  Moreover, as shown in FIG. 7, the stop member 35 which suppresses the concave mirror 31 can also be provided. The stop member 35 is provided at two locations 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 reflecting surface side of the concave mirror 31 through the elastically deformable cushioning material 36, and can maintain the holding state of the concave mirror 31 by absorbing a dimensional change due to thermal deformation. The stop member 35 is fixed by fastening a screw (not shown) to the holder 32 with the concave mirror 31 interposed.

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

  The pressing force can also be applied by the buffer material 36. In addition, even if the relative position change between the stop member 35 and the concave mirror 31 occurs during thermal deformation, the concave mirror 31 reduces the influence on the reflecting surface due to the displacement of the cushioning material 36 due to deformation or slippage. The positioning and holding state can be maintained. As the buffer material 36, for example, a foamed urethane material or a member such as synthetic rubber can be applied.

  Further, in the above-described embodiment, the base portions 32c and 321c of the holders 32 and 321 are shown as being formed in a linear or arc-shaped linear shape (protrusion), but other shapes and irregular shapes may be used. 8 may be replaced with a circular base 322c. Even in this case, among the plurality of base parts 322c, the base part 322c in the vicinity of the position Q facing the substantially center of the concave mirror 31, that is, the base part 322c provided on the inner side, is more than the outer base parts 322c. The area per one is made small. Thereby, in holding the concave mirror 31 by the holder 322, the adhesive strength in the vicinity of the center of the concave mirror 31 can be set stronger than the outer adhesive strength.

  For this reason, as in the above-described embodiment, the degree of distortion of the display on the reflecting surface that reflects the display light L in the vicinity of the center of the image that is the main part of the HUD device A can be reduced, and the display quality is reduced due to changes in the environmental temperature. Can be suppressed.

  The head-up display device of the present invention has been described by way of example in the configuration of the above-described embodiment, but the present invention is not limited to this, and the gist of the present invention can be applied to other configurations. It goes without saying that various improvements and display changes can be made without departing from the scope.

  For example, in the above-described embodiment, the liquid crystal display 1 that forms a display image using the light emitted from the light source 11 has been described as an example. However, the present invention may be applied by scanning laser light as illumination light. A projector system using a DMD (digital mirror device) can also be applied. By combining the mirror units, the same effects as in the above-described embodiment can be obtained.

  Moreover, in the above-mentioned cold mirror 21, this can be omitted depending on temperature conditions (heat generation of electronic components such as a light source), sunlight irradiation conditions, etc. For example, display light from the liquid crystal display 1 can be reduced. Even in the configuration in which projection is performed on the front windshield D through reflection by the concave mirror 31, the same effect as in the above embodiment can be obtained. Further, the holder 32 can be applied even if it has a substantially flat plate shape having the above-described pedestal portion, and can be easily processed.

  The present invention relates to a mirror unit, for example, mounted on a moving body including 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.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display 2 1st reflector 3 2nd reflector (mirror unit)
31 Concave mirror (reflection mirror)
32, 321, 322 Holder 32c, 321c, 322c Base 34 Adhesive member 4 Housing A HUD (head-up display) device

Claims (4)

A reflective mirror having a reflective surface on a plate-like substrate;
A holder for rotatably holding the reflecting mirror;
An adhesive member for fixing the reflection mirror to the holder,
The holder is provided with a convex base on which the adhesive member is placed,
The mirror unit of the head-up display device, wherein the base portion is formed such that, on the opposing surface of the reflecting mirror, the inner opposing surface has a larger area than the outer opposing surface. 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 base portions are formed in a line shape substantially perpendicular to a 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 circular arc shape contrasting with a 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 formed of different materials.

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