JP2017049570A - Mirror unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror unit that features minimal distortion of a reflective surface due to temperature changes and is configured to hold a reflective mirror at a desired position.SOLUTION: A mirror unit consists of a concave mirror 41 comprising a reflective surface formed on a tabular substrate 41a, and a holder 42 made of a material different from that of the substrate 41a and configured to hold the concave mirror 41. The holder 42 and the concave mirror 41 are in contact with each other via a plurality of protrusions 41c on their respective counter surface sides to be held together. The holder 42 comprises a support body 421 configured to be in contact with a rear surface of the reflective surface via the protrusions 41c, and retaining members 422 for holding the concave mirror 41 between themselves and the support body 421. In a planar direction X of the concave mirror 41, the concave mirror 41 and the retaining members 422 are positioned to have a gap D therebetween.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a mirror unit that projects a display image, and is suitable, for example, as a mirror unit used in an in-vehicle display device such as a head-up display.

  Conventionally, as a display device using a mirror unit having a reflection mirror that reflects display light, there is a head-up display, which is disclosed in Patent Document 1, for example. Such a 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 display light emitted from a display device onto a windshield (projection member) 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 windshield, a light source, a display, and a mirror unit. And a housing made of a synthetic resin having a translucent part that transmits the display light reflected by the mirror unit, and the display light reflected by the reflection mirror of the mirror unit is A virtual image is displayed by projecting onto the windshield through the translucent part.

JP-A-9-109732

  These head-up displays are mounted on a vehicle and have a large temperature change such as a high temperature due to sunlight irradiation as well as a change in temperature environment outside the vehicle. For this reason, there existed a subject that a display state will be distorted by the stress being added to a mirror surface by the difference in the expansion coefficient by the temperature change of a reflective mirror and the holder holding this reflective mirror.

  In particular, when the mirror unit is large or the material of the reflecting mirror base material and the holder are different, the above-mentioned problem becomes prominent. A structure that can hold the reflection mirror in position has been desired.

  Accordingly, an object of the present invention is to provide a mirror unit that pays attention to the above-described problem and has a small reflection surface distortion even when there is a temperature change and holds the reflection mirror at a desired position.

The mirror unit of the present invention is
A reflective mirror having a reflective surface on a plate-like substrate;
It is made of a material different from the base material, and includes a holder for holding the reflection mirror,
The holder and the reflection mirror are held in contact with each other through a plurality of abutting portions on the opposing surfaces,
The holder is provided with a support body that contacts the back surface side of the reflection surface via the contact portion, and a stop member that is sandwiched between the support body and holds the reflection mirror,
In the surface direction of the reflection mirror, the reflection mirror and the stopper member are provided at an interval.

  The holder may be configured to sandwich the reflection mirror while applying a pressing force to the reflection mirror by the elasticity of the stopper member.

  Further, an elastically deformable cushioning material is provided between the stopper member and the reflection mirror.

  Further, the contact portion is provided with a convex portion for positioning in the surface direction between the reflection mirror and the support and a rib in a direction perpendicular to the surface between the reflection mirror and the support at different locations. Features.

  In addition, the rib is formed at a position overlapping the holding position of the reflection mirror by the stopper member.

  The mirror unit of the present invention has little distortion on the reflecting surface even when there is a temperature change, and can hold the reflecting mirror at a desired position.

1 is a schematic view of a head-up display according to an embodiment of the present invention. Sectional drawing of the display apparatus by the embodiment. The figure which shows the mirror unit by the embodiment. Sectional drawing which shows the principal part of the mirror unit by the embodiment. The figure which shows the contact surface side with the concave mirror of the support body by the embodiment. Sectional drawing which shows the principal part of the modification of the embodiment. The figure which shows the contact surface side with the support body of the concave mirror by other embodiment of this invention. The figure which shows the contact surface side with the concave mirror of the support body by other embodiment. Sectional drawing which shows the principal part of the mirror unit by other 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 is a windshield of the vehicle 10 that is a projection member for display light L that is projected by a display device 12 that is a display unit disposed inside an instrument panel (instrument panel) 11 of the vehicle 10. The (virtual windshield) 13 is reflected in the direction of the driver (user) 14 of the vehicle 10 to display the virtual image V. In other words, the head-up display emits (projects) display light L emitted from a liquid crystal display 20 (to be described later) of the display device 12 onto the windshield 13 and operates a display image (virtual image) V obtained by the emission. The person 14 is made to visually recognize. As a result, the driver 14 can observe the virtual image V displayed in front of the driver's seat superimposed on the landscape.

  As shown in FIG. 2, the display device 12 mainly includes a liquid crystal display 20, a first reflector 30, a second reflector 40 that is a mirror unit, and a housing 50.

  The liquid crystal display 20 is disposed facing the illumination direction of the light source 21 so as to form a display light L by transmitting the illumination light from the light source 21 mounted on the wiring board H and the light source diode. TFT type liquid crystal display element 22 is provided. This is because a light source 21 is provided behind the liquid crystal display element 22 (opposite to the emission of the display light L), and the liquid crystal display element 22 projects and displays predetermined information through the light emitted from the light source 21. It means that.

  The liquid crystal display 20 is provided in the housing 50 such that the surface on the emission side of the display light L faces a cold mirror (to be described later) of the first reflector 30, and the optical axis of the display light L is on the cold mirror. Fixed and held at a crossing position and orientation.

  In addition, the liquid crystal display element 22 forms an image of predetermined information (for example, vehicle information such as the speed of the vehicle 10, 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 20 uses the illumination light from the light source 21 to output display light L composed of light in the visible wavelength range. For example, a light source 21 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 22. Needless to say, the predetermined information formed by the liquid crystal display element 22 is not limited to vehicle information such as the speed of the vehicle and the engine speed, and any display form such as a time and a moving image can be adopted.

  The first reflector 30 has a cold mirror 31 and a fixing member 32 for mounting and fixing the cold mirror 31 using a predetermined fixing means. The cold mirror 31 includes a substantially rectangular glass substrate 31a and a reflective layer 31b formed on one surface of the glass substrate 31a (a surface facing a concave mirror described later of the second reflector 40). The reflective layer 31b is made of multilayer interference films having different film thicknesses, and is formed by a method such as vapor deposition. The cold mirror 31 is provided in an inclined state at a position where the display light L emitted from the liquid crystal display 20 (liquid crystal display element 22) is reflected toward the second reflector 40 (the concave mirror).

  The cold mirror 31 reflects light in the visible wavelength range (450 to 750 nm) including the emission wavelength range of the liquid crystal display 20 with a high reflectance (for example, 80% or more), and lowers light outside the visible wavelength range. What reflects with reflectivity is suitable. In this case, a cold mirror 31 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 (for example, 15% or less) is applied. The light that is not reflected by the reflective layer 31 b is configured to pass through the cold mirror 31. The fixing member 32 is made of a synthetic resin material and is fixed to the housing 50.

  As shown in detail in FIGS. 3 and 4, the second reflector 40 that is a mirror unit includes a concave mirror 41 that is a reflecting mirror provided in the housing 50 to reflect the display light L from the cold mirror 31, and this A holder 42 for holding the concave mirror 41 and a driving means 43 for rotating the holder 42 on which the concave mirror 41 is mounted and adjusting the inclination angle of the concave mirror 41 are provided.

  The concave mirror 41 is made of a plate-like substrate 41a made of a synthetic resin (for example, polycarbonate) and a metal such as aluminum deposited on the front surface 45 of the substrate 41a (that is, the surface facing the reflective layer 31b of the cold mirror 31). The reflective surface formed by the reflective film 41b is a concave curved surface (concave surface) having a predetermined curvature. In this case, the substrate 41a is formed by injection molding.

  Therefore, the reflective film 41b formed as the concave surface serves as a light reflecting surface for reflecting the display light L from the cold mirror 31 to the windshield 13 side. The concave mirror 41 is provided in an inclined state at a position where the reflecting surface of the reflecting film 41 b faces the cold mirror 31 and the upper windshield 13 and faces a translucent cover (to be described later) of the housing 50.

  Further, the concave mirror 41 reflects (projects) the display light L from the cold mirror 31 toward the translucent cover (the windshield 13 of the vehicle 10). This means that the concave mirror 41 enlarges the display light L reflected by the cold mirror 31 and projects the enlarged display light L onto the windshield 13 through the translucent cover. In this case, the reflecting surface of the concave mirror 41 has a curved surface shape that can be corrected so as to reduce the distortion of the virtual image V in accordance with the curved surface shape of the windshield 13.

  The holder 42 is for holding the concave mirror in a predetermined position. The support body 421 made of a metal material close to the linear expansion coefficient (thermal expansion coefficient) of the housing 50 and the support body 421 are separated from each other. 422. For example, an aluminum die casting can be applied as the support 421, and a sheet metal member such as aluminum or a synthetic resin such as polycarbonate can be applied as the stopper member 422.

  The support 421 is provided on the back side of the concave mirror 41 (opposite to the reflecting surface), and as shown in FIG. 5, a shaft portion 42a, a positioning hole 42b, a groove portion 42c, and a flat surface 42d are formed. .

  The shaft portion 42 a supports the rotation of the concave mirror 41 by the driving means 43, and is supported by a holding portion formed on the housing 50. The shaft portion 42a may be pivotally supported on the housing 50 via a bearing.

  The positioning hole 42b is formed so as to face a spherical convex portion (contact portion) 41c formed in the concave mirror 41, and one of the plurality of convex portions 41c is fitted into the positioning hole 42b so that the concave mirror 41 faces the surface. Can be controlled. In this case, the positioning hole 42b can be positioned so that an inclined surface is formed and the convex portion 41c is guided to the center side of the positioning hole 42b.

  The groove part 42c is formed at a position facing the convex part 41c similarly to the positioning hole 42b, and serves as a regulating means for regulating the position of the concave mirror 41 so that the convex part 41c can slide on a predetermined line. The groove 42c restricts movement in the rotational direction around the positioning hole 42b with respect to the positioning state of the concave mirror 41 by the positioning hole 42b, and causes thermal deformation (thermal expansion and contraction) of the concave mirror 41. In consideration of the above, it is formed in a linear shape from the center to the outside. That is, even if the concave mirror 41 is thermally deformed, the positioning state in which the convex portion 41c is fitted in the positioning hole 42b and the groove portion 42c can be maintained. In addition, the shape of the groove part 42c should just be a magnitude | size corresponding to the spherical shape of the convex part 41c, and may be a V groove or a U groove.

  As described above, the flat surface 42d is formed at a position facing the convex portion 41c of the concave mirror 41, and is in contact with the convex portion 41c together with the positioning hole 42b and the groove portion 42c. Therefore, since the concave mirror 41 and the support 421 are opposed to each other at three locations using the three convex portions 41c corresponding to the positioning hole 42b, the groove portion 42c, and the flat surface 42d, Even if the relative position of the convex portion 41c at the location of the groove portion 42c and the flat surface 42d changes due to the difference in thermal expansion coefficient with the support body 421, it is only necessary to slide in the desired direction while maintaining the contact state. It can maintain the holding state while responding to the change without swaying.

  The stop member 422 is a member for holding the concave mirror 41 positioned in the surface direction by the positioning hole 42b or the like so as to press it from the reflecting surface side. In this case, the stop member 422 is provided at two locations so as to hold the vicinity of the side (end portion) facing the longitudinal direction (rotation axis direction) of the concave mirror 41. Further, the stopper member 422 is in contact with the reflecting surface side of the concave mirror 41 via the elastically deformable cushioning material 423, and can maintain the holding state of the concave mirror 41 by absorbing a dimensional change due to thermal deformation. The stop member 422 is fixed by screwing the support 421 with the concave mirror 41 interposed.

  Further, in this case, the stopper member 422 is formed by pressing a metal plate, and is provided so as to be elastically deformable. The concave mirror 41 can be sandwiched between the support body 421 while applying this elastic force as a pressing force to the concave mirror 41.

  The pressing force can also be urged by the buffer material 423. In addition, even if the relative position change between the stop member 422 and the concave mirror 41 occurs during the thermal deformation, the concave mirror 41 reduces the influence on the reflection surface due to the displacement of the cushioning material 423 and the displacement due to slippage. The positioning and holding state can be maintained. As the buffer material 423, for example, a foamed urethane material or a member such as synthetic rubber can be applied.

  With the configuration of these holders 42, even if the concave mirror 41 made of a synthetic resin material is thermally deformed, not only can the shaft support state with the housing 50 be maintained, but also a desired reflecting surface position can be secured.

  The driving means 43 can change the angle of the concave mirror 41 by using a stepping motor 43a that generates a driving force by energization and the rotation of the stepping motor 43a. In this case, the driving means 43 moves a lead screw type screw formed on the rotating shaft of the stepping motor 43a fixed to the housing 50 in a linear direction, and pushes and pulls the arm portion 42e extending from the concave mirror 41 with the screw. Thus, the concave mirror 41 is configured to rotate about the shaft portion 42a. The drive unit 43 can be applied to a rack and pinion type other than the lead screw type, or a configuration in which a stepping motor rotates the shaft portion 42a via a gear or the like.

  The housing 50 is formed in a substantially box shape by combining, for example, a black light-shielding synthetic resin material molded part or a metal member (aluminum die-casting), and the liquid crystal display 20 and the first part are formed in the space 51 that is the internal space. The second reflectors 30 and 40 are held and accommodated. These accommodating parts are held by a holding body 52 made of a metal material.

  In addition, the housing 50 has an upper portion (front glass 13 side) where the concave mirror 41 is disposed in the second reflector 40, and a translucent cover 53 that is a translucent portion is disposed so as to close the opening. It becomes. The translucent cover 53 is made of a translucent synthetic resin material (for example, acrylic resin), is formed in a curved shape (curved surface shape), and transmits light that allows the display light L reflected by the concave mirror 41 to pass (pass). It has a function as a sex member. In other words, the display light L reflected by the concave mirror 41 is projected onto the windshield 13 through the translucent cover 53 formed in the housing 50, whereby the virtual image V is displayed to the driver 14.

The second reflector (mirror unit) 40 of such a head-up display includes a concave mirror 41 having a reflecting surface on a plate-like base material 41a, and a holder 42 for holding the concave mirror 41 made of a material different from the base material 41a. The holder 42 and the concave mirror 41 are held in contact with each other via a plurality of abutting portions 41c on their opposing surfaces, and the holder 42 has the abutting portion 41c on the back side of the reflecting surface. And a stop member 422 that is sandwiched between the support body 421 and holds the concave mirror 41. The concave mirror 41 and the stop member 422 are provided at a distance D in the surface direction of the concave mirror 41.
Therefore, by providing the distance D, even if the relative position changes due to the difference between the thermal deformation of the concave mirror 41 and the thermal deformation of the support 421 and the stop member 422, the stop member 422 and the concave mirror 41 are in the plane direction X. Since the contact can be prevented, it is possible to prevent the concave mirror 41 from being distorted by the stress due to the contact, and to prevent display influence.

The plate-like substrate 41a includes a concave mirror 41 having a reflecting surface, and a holder 42 made of a material different from the substrate 41a and holding the concave mirror 41. The holder 42 and the concave mirror 41 include a plurality of The convex portion 41 c contacts the convex portion 41 c, and one convex portion 41 c among the plurality of convex portions 41 c positions and fixes the holder 42 and the concave mirror 41, and the other convex portion 41 c slides the concave mirror 41 with respect to the holder 42. Abuts movably.
Therefore, even if there is a temperature change, the distortion of the reflecting surface is small, and the concave mirror 41 can be held at a desired position. This is particularly advantageous because the concave mirror 41 can be held even in a case where a change in heat is severe, such as the heat generation time of the light source 21 and the presence or absence of sunlight irradiation, as in a head-up display mounted on a vehicle.

  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, the convex portion 41c is formed on the concave mirror 41 side, and the concave positioning hole 42b and the groove portion 42c corresponding to the convex portion 41c are provided on the holder 42 side, but the contact portion is either the concave mirror or the holder. The contact portion may have a concave-convex relationship by providing a convex shape on the holder side and a concave portion on the concave mirror side.

  In the above-described embodiment, the liquid crystal display 20 that forms a display image using the light emitted from the light source 21 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 31, 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 20 can be reduced. Even if it is the structure which projects on a windshield through reflection by a concave mirror, the effect similar to the above-mentioned embodiment can be acquired.

  Further, as shown in FIG. 6, a substantially flat plate can be used as the support 421 of the holder 42, and it is easy to process. Further, when the support 421 and the fixing member 422 are fixed, screws can be fixed on a surface other than the reflecting surface. For example, the screw B may be screwed to the side surface or the back surface as shown in FIG. . Further, not only a screw stop but also an engagement structure using a hook may be combined.

  Further, as shown in FIG. 6, in addition to the flat plate-like material, a buffer material 423a having a spherical shape, a cylindrical shape, or a column shape can be applied, and the contact area with the concave mirror 41 and the stop member 422 can be reduced. By doing so, it becomes easy to carry out position shift and elastic deformation between the concave mirror 41 or the stop member 422. Further, the cushioning material can be adhered to either the stop member 422 or the concave mirror 41. For example, the stopper member 422 can be attached to the surface of the stop member 422 facing the concave mirror 41 via an adhesive sheet, and positioning is facilitated.

(Other embodiments)
Next, another embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is described in the same or equivalent location as the above-mentioned embodiment, The detailed description is abbreviate | omitted.

  In another embodiment, as shown in FIG. 7, ribs 41 d are provided in addition to the convex portions 41 c as contact portions formed on the concave mirror 41. Further, as shown in FIG. Is provided with a flat portion 42 d for contacting the rib 41.

  As shown in FIG. 9, the rib 41 d and the flat portion 42 d in contact with the rib 41 d are arranged so as to be in surface contact with each other, and as a spacer in the direction in which the concave mirror 41 and the support 421 are stacked (the vertical direction of each surface) Y, There is an effect of maintaining a predetermined interval. The rib 41d can not only relieve stress concentration at the convex portion 41c, but also, for example, even if a positional deviation in the surface direction X occurs due to a difference in thermal deformation (expansion or contraction) between the concave mirror 41 and the support 421. The predetermined interval can be maintained. Therefore, as in the above-described embodiment, there is an effect that the concave mirror 41 can be held at a desired position with little distortion of the reflecting surface even when there is a temperature change.

  In addition, the rib 41 d is in contact with the flat portion 42 d at a position where the stopper member 422 overlaps with the portion where the concave mirror 41 is held via the cushioning material 423. Thereby, for example, when the concave reflector 41 receives a load in the perpendicular direction Y when the second reflector 40 is assembled, the load on the convex portion 41c can be reduced by the contact of the support body 421 with the rib 41d. Deformation and breakage of the convex portion 41c can be prevented.

  The present invention relates to a mirror unit and is suitable as an in-vehicle display device such as vehicle information and road information such as turn-by-turn display mounted on a moving body including an automobile, a motorcycle, or an agricultural machine or a construction machine.

12 Display Device 20 Liquid Crystal Display 30 First Reflector 40 Second Reflector (Mirror Unit)
41 Concave mirror
41a Substrate (base material)
41b Reflective film 41c Convex part (contact part)
41d rib (contact part)
42 Holder 421 Support body 422 Stopping member 423 Buffer material 42a Shaft portion 42b Positioning hole 42c Groove portion (regulating means)
42d Flat part 43 Driving means 43a Stepping motor 50 Housing L Display light D Interval X Surface direction Y Surface normal direction

Claims (5)

A reflective mirror having a reflective surface on a plate-like substrate;
It is made of a material different from the base material, and includes a holder for holding the reflection mirror,
The holder and the reflection mirror are held in contact with each other through a plurality of abutting portions on the opposing surfaces,
The holder is provided with a support body that contacts the back surface side of the reflection surface via the contact portion, and a stop member that is sandwiched between the support body and holds the reflection mirror,
In the surface direction of the reflection mirror, the reflection mirror and the stop member are provided at an interval.   The mirror unit according to claim 1, wherein the holder sandwiches the reflection mirror while applying a pressing force to the reflection mirror by elasticity of the stopper member.   The mirror unit according to claim 1, further comprising an elastically deformable cushioning material between the stopper member and the reflection mirror.   The contact portion is provided with a convex portion for positioning in the surface direction of the reflection mirror and the support, and a rib in a direction perpendicular to the surface of the reflection mirror and the support at different locations. The mirror unit according to claim 1.   5. The mirror unit according to claim 4, wherein the rib is formed at a position overlapping a holding portion of the reflection mirror by the stopper member.

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