JPH10236230A - Room mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glare-proof function, and provide an effect of a convex mirror by forming a hologram as a hologram to reflect and diffract a backward image toward a driver at an installation angle different from a prescribed installation angle of a room mirror in which the backward image is visually confirmed toward the driver by a reflecting layer. SOLUTION: A hologram 1 is stuck to a reflecting layer 5 and an opposite side surface of a glass plate 4, and another one glass plate 2 is laminated through a laminated intermediate film 3 of polyvinyl butyral. A diffraction condition of the hologram 1 is decided so that the light incident at an incident angler α is reflected and diffracted at an angle β of diffraction. When an installation angle of a room mirror 12 is changed by ϕ, an image in the light 20 diffracted by the hologram 1 is visually confirmed. The residual light passing through the hologram 1 becomes the light 19 reflected by the reflecting layer 5 on the reverse side of the glass plate, and this light turns in the downward direction of an observer. A glare-proof function is obtained by switching an installation angle of the room mirror.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mirror which is provided in a vehicle such as a vehicle and is used by an observer as a driver to visually recognize information on the rear and side, that is, a rearview mirror.
The present invention relates to a mirror called a rearview mirror or an inside rearview mirror (hereinafter, typically referred to as a room mirror), and more particularly to a room mirror having an anti-glare function effective against dazzling caused by a headlamp from a rear vehicle or the like. .

[0002]

2. Description of the Related Art Conventionally, a vehicle such as an automobile is provided with a rearview mirror as a means for obtaining rearward information while a driver faces forward. This mirror is obtained by applying a metal plating, a metal deposition, or a reflective layer of a metal film to a glass plate or a plastic plate conventionally used as a normal mirror.

[0003] In this rearview mirror, since the light of the headlamp of the following vehicle is reflected by the rearview mirror at night and dazzles when entering the driver's eyes, the rearview mirror often has an anti-glare function. . A room mirror with a general anti-glare function utilizes the reflection of the surface of the mirror and the reflection of a reflective layer, and polished a glass plate as a base material into a wedge shape, and reflects a metal film or the like on the back side of the glass plate. Layered. 5 and 6 are views for explaining the principle of a conventional rearview mirror having an antiglare function. FIG. 5 is a conceptual diagram showing a normal use state of the conventional rearview mirror, and FIG. 6 is an antiglare of the conventional rearview mirror. It is a conceptual diagram which shows the use condition which acquires a function.

In FIG. 5, a rear image is visually recognized by light 25 reflected by a reflection layer 24 on the back side of the glass plate.
The light 26 due to the reflection of the surface travels downward of the viewer 21 as shown in the figure. On the other hand, when the installation angle of the room mirror 22 is changed in the direction of the arrow shown in FIG. 5 and the state shown in FIG. 6 is obtained (the angle θ is changed from the state shown in FIG. 5), the image by the reflected light 28 on the glass plate surface is visually recognized. The reflection layer 2 on the back side of the glass plate
The image formed by the light 27 reflected by the light 4 goes upward of the viewer 21. In general, the reflectivity of a reflective layer such as a metal film provided on the back surface of a glass plate is manufactured to be about 90%, whereas the reflectivity at the surface of the glass plate, that is, at the interface between air and the glass plate is 4%. %, The anti-glare function can be obtained by switching the installation angle of the room mirror between the reflection by the reflection layer on the back surface of the glass plate and the reflection on the surface of the glass plate. The switching is facilitated by making the base material wedge-shaped.

On the other hand, room mirrors are generally plane mirrors, but some use a convex mirror that is convex in a horizontal section. The use of this convex mirror has the advantage that a wider range can be seen than a plane mirror with the same mirror area.

[0006]

However, it is technically and costly to process a glass plate as a base material into a wedge shape, and further form a convex mirror, like a room mirror using a normal plane mirror. From the standpoint of mass production. Therefore, a room mirror composed of a convex mirror having an anti-glare function by switching the installation angle as described above has not been put to practical use.

As a result, in order to prevent dazzling even when the light of the headlamp of the following vehicle is reflected at night, a reflection layer made of chromium evaporation or the like having a lower reflectance than a reflection layer made of aluminum evaporation is used. In many cases, the reflected image is darkened even in a normal use state. For this reason, there has been a demand for a room mirror having an anti-glare function by switching the installation angle and having the effect of a convex mirror, like a room mirror having an anti-glare function by a normal plane mirror.

[0008]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and comprises at least a glass plate and a reflection layer provided on the glass plate. Is a rearview mirror used for confirming the rear side, and a hologram is arranged on the surface of the glass plate opposite to the reflection layer, and the hologram has a rear image directed to the driver by the reflection layer. The present invention provides a room mirror, which is a hologram that reflects and diffracts a rear image toward a driver at an installation angle different from a predetermined installation angle of the room mirror visually recognized.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a schematic horizontal sectional view showing an example of a room mirror according to the present invention. The horizontal direction refers to the horizontal direction when the rearview mirror is mounted on the vehicle. In the figure, 1 is a hologram, 2 is an inorganic glass plate, 3 is an intermediate film, and 4 is an inorganic glass plate on which a reflective layer 5 is formed. The lower part of the figure is the vehicle interior (driver direction), and the upper part is the vehicle exterior. .
In this example, the inorganic glass plates 2 and 4 are 66 mm wide and 27 mm long.
It was 0 mm and had a horizontal curvature R = 1500 mm, and was manufactured as a pair using a glass plate bending method usually used when manufacturing a windshield made of laminated glass. Then, the reflection layer 5 was formed on the vehicle outer side surface of the inorganic glass plate 4 which is the vehicle outer side of the two inorganic glass plates by aluminum evaporation.

A hologram 1 is attached to a surface of the glass plate 4 on the side opposite to the reflection layer 5, and another glass plate 2 is laminated via an interlayer 3 of polyvinyl butyral. Note that a protective layer (not shown) such as a polyvinyl alcohol film is provided on the intermediate film side of the hologram 1 in order to prevent the hologram 1 from being adversely affected by a plasticizer or the like contained in the intermediate film 3. It is also preferable to provide a protective layer (not shown) for preventing deterioration due to oxidation or the like. Then, the laminated body is held in a frame made of a predetermined resin or the like, and is attached to a position where the rearview mirror of the vehicle is installed.

FIGS. 2 and 3 are diagrams for explaining the principle of the rearview mirror having the anti-glare function of the present invention having the above-described structure. FIG. 2 is a conceptual diagram showing a normal use state of the rearview mirror of the present invention. FIG. 3 is a conceptual diagram showing a use state of the room mirror of the present invention for obtaining an antiglare function.

In FIG. 2, since the rear image does not match the diffraction condition of the hologram 1 in the present embodiment, most of the light is transmitted and the image is visually recognized by the light 17 reflected by the reflection layer 5 on the back side of the glass plate.

The diffraction condition of the hologram 1 is set so that light incident at an incident angle α is reflected and diffracted at a diffraction angle β.
The light whose diffracted light 18 enters the driver's eyes in conformity with the diffraction condition is light from above (light having an incident angle α) as shown in the figure. Usually this direction is the ceiling of the vehicle,
In particular, it is hardly visible when driving at night.

When the installation angle of the room mirror 12 is changed by φ in the direction of the arrow shown in FIG. 2, the state shown in FIG. 3 is obtained, and the image of the light 20 diffracted by the hologram 1 is visually recognized. The remaining light transmitted through the hologram 1 becomes light 19 reflected by the reflection layer 5 on the back side of the glass plate, and this light is directed downward from the viewer. As described above, since the anti-glare function can be obtained by switching the installation angle of the rear-view mirror, similarly to the conventional rear-view mirror having the anti-glare function, the handling is well known even to the driver who is the user. It is easy.

Usually, the change and adjustment of the installation angle of the room mirror is about 1 to 10 degrees. Therefore, since the incident / reflection angles (α, β) are determined in accordance with this, the slant angle of the diffraction grating inside the hologram is preferably 1 to 10 degrees with respect to the reflection layer in the vertical direction.

The hologram 1 used in this embodiment is a reflection hologram, which is a parallel hologram for both reference light and object light and is exposed from both sides of the hologram material.
Degrees and the diffraction angle β = 5 degrees.

Exposure of the hologram is performed by using an A beam having a wavelength of 476 nm.
r laser light, a dye laser light having a wavelength of 580 nm, and a Kr laser light having a wavelength of 647.1 nm were coaxially superposed on each other. After the laser exposure, ultraviolet irradiation and heat treatment were performed to produce a hologram.

FIG. 4 shows the spectral characteristics of the hologram 1 at a predetermined angle. The reflectance in the visible light region is about 5 in this example.
%, Which has a lower reflectance than the reflection by the reflection layer 5 and thus has an effect of attenuating light and functions as an anti-glare mirror.

When an experiment was conducted with the configuration of the present invention using the hologram 1 in this example, the characteristics of the hologram 1 were as shown in FIG. It could be confirmed.

In this embodiment, the size of the effective area of the hologram 1 is 60 mm in width and 264 mm in length. As described above, the area of the effective area of the hologram is made smaller than the area of the transparent substrate, and in particular, the width 3 along the outer periphery of the glass plate.
It is preferable to provide an ineffective area of not less than mm because a change in the characteristics of the hologram due to entry of some substance from the outer periphery of the substrate can be minimized.

Since the hologram 1 of this embodiment is made of parallel light for both the reference light and the object light and gives diffraction only in the vertical direction, the diffraction grating in the hologram 1 is formed almost only in the horizontal plane direction. For this reason, by enclosing the hologram in a glass plate having the above-mentioned curvature, the hologram was deformed following the glass plate, and an effect equivalent to the effect of the convex surface due to the curvature of the glass plate was obtained in the horizontal direction. .

The hologram in the present invention is preferably a hologram that is multiple-exposed with light of a plurality of wavelengths as in the present embodiment, but a laminated hologram in which a plurality of holograms that are exposed with light of one or more wavelengths are laminated. May be used. Since this example is a single hologram, it is preferable because coloring due to the hologram material can be suppressed.
Further, the plurality of diffraction wavelengths is not limited to the wavelength of the present example, and may be more than three wavelengths. The respective efficiencies and half widths are also determined in consideration of the required reflectance, antiglare effect, and color tone. Further, the efficiency of the diffraction wavelength and the half-value width can be changed by the irradiation energy of the laser at the time of producing the hologram by exposure and the swelling treatment of the hologram.

The hologram used in this example has a thickness of 20 μm.
And a volume phase type hologram. As the hologram material, in addition to the above, various photosensitive materials such as a polyvinyl carbazole-based photopolymer, gelatin dichromate, a photo resist, and a silver salt can be used. Although it is desirable in terms of obtaining efficiency, holograms such as emboss type and rainbow type can also be widely used. Among them, those having high transparency are preferable.

Although the hologram 1 is attached to the glass plate 4 on which the reflection layer 5 is formed, the hologram 1 may be attached to the inner side of the glass plate 2 or the intermediate film 3. Further, a hologram may be attached to a single glass plate having a reflective layer without using laminated glass, and a laminated structure of (protective film) / hologram / glass plate / reflective layer may be employed. It is preferable to enclose the hologram in laminated glass from the viewpoint of protection from external factors such as external environment and abrasion. Also, since the intermediate film often contains an ultraviolet absorber, it is better to make the light passing through the intermediate film hit the hologram as in this example.
It is preferable in terms of improving durability.

Further, as another configuration, the hologram may be adhered on the reflection layer on the intermediate film side.

In addition, the structure of the laminate is not limited to an inorganic glass plate, and a hologram may be formed on a transparent substrate and a transparent substrate or a transparent film using an adhesive or an adhesive by using a transparent substrate called so-called resin glass. Lamination may be performed, but a laminated glass structure as in this example is preferable in consideration of the performance and durability as a mirror.

Although it is possible to give a magnification to the hologram, the hologram may have an uncomfortable feeling such as a difference in size between an image due to diffraction of the hologram and an image reflected by the reflection layer. It is preferable that the hologram has no magnification exposed by light.

Further, a normal rearview mirror is often provided with a film for preventing scattering on the rear surface so that fragments of the glass plate are not scattered in case of breakage, but it has a laminated glass structure. This also has the effect of preventing scattering.

[0029]

According to the rearview mirror of the present invention, it is possible to provide the antiglare function while providing the function of the convex mirror without using a wedge-shaped glass plate which is difficult to form a convex shape in order to provide the antiglare function. Can be.

[Brief description of the drawings]

FIG. 1 is a schematic horizontal sectional view showing an example of a room mirror according to the present invention.

FIG. 2 is a conceptual diagram showing a normal use state of the room mirror of the present invention.

FIG. 3 is a conceptual diagram showing a use state of the room mirror of the present invention for obtaining an antiglare effect.

FIG. 4 is a graph showing characteristics of a hologram attached to a room mirror according to the present invention.

FIG. 5 is a conceptual diagram showing a normal use state of a conventional room mirror.

FIG. 6 is a conceptual diagram showing a use state of a conventional room mirror for obtaining an antiglare effect.

[Explanation of symbols]

 1: Hologram 2, 4, 23: Glass plate 3: Intermediate film 5, 24: Reflective layer 12, 22: Room mirror 17, 19, 25, 27: Light reflected by reflective layer 18, 20: Light diffracted by hologram 21: Viewer 26, 28: Light reflected by the glass plate surface

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G02B 17/00 G02B 17/00 B

Claims (5)

[Claims] 1. A rearview mirror comprising at least a glass plate and a reflection layer provided on the glass plate, the rearview mirror being provided in a vehicle and used by a driver to check the rear, wherein the reflection layer of the glass plate is provided. A hologram is arranged on the surface on the side opposite to the hologram, and the hologram forms a rear image at an installation angle different from a predetermined installation angle of a room mirror in which a rear image is viewed toward a driver by a reflective layer. A room mirror, which is a hologram that reflects and diffracts light toward a driver. 2. The room mirror according to claim 1, wherein the horizontal cross section of the room mirror has a curved shape. 3. The laminated hologram according to claim 1, wherein the hologram is sealed in a laminated glass composed of a glass plate having the reflection layer and another glass plate.
The described room mirror. 4. The room mirror according to claim 1, wherein a slant angle of the diffraction grating inside the hologram is 1 to 10 degrees with respect to the reflection layer in a vertical direction. 5. The hologram according to claim 1, wherein the hologram is a hologram that is multiple-exposed with light of a plurality of wavelengths, or is a laminated hologram in which a plurality of holograms that are exposed with light of one or more wavelengths are stacked. The room mirror according to any one of claims 1 to 4.