JPH1111212A - Room mirror - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mirror with also a glare-proof function, providing the mirror with a function of a convex mirror by transmitting and diffracting a rear image toward a reflection layer at an installion angle of hologram which is different from a prescribed installation angle of a room mirror in which the rear image is visualized toward a driver by the reflection layer. SOLUTION: Light entering into the eyes of a driver by light which is diffracted by hologram 1 and reflected by a reflection layer 5 is light from the upper direction (light of an incident angle α). Because this direction is normally a ceiling part of a vehicle, the direction is hardly visualized at the time of a night driving, in particular. When an installation angle of a room mirror 12 is changed by ϕ, an image by light 20 which is diffracted by hologram 1 and reflected by the reflection layer 5 is visualized. The remaining light transmitting hologram 1 becomes light 19 reflected by the reflection layer 5 on the back side of a glass plate and this light becomes the lower direction of an observer. The installation angle of the room mirror can be normally changed/ adjusted up to about 1 to 10 degrees.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[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 on the surface is directed downward from 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 at 4 is directed upward from 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%, while 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 the horizontal direction. 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.

In Japanese Patent Application No. 9-46300, the present applicant uses a reflection type hologram inside a glass plate having a reflection layer and switches between reflection of the reflection layer and diffraction of the hologram depending on the installation angle of the room mirror. We have proposed a convex rearview mirror having an antiglare effect. However, since the half width of the diffraction wavelength of the reflection hologram is narrower than that of the transmission hologram, the transmitted light is observed as a complementary color and is not good-looking. Further, in a reflection type hologram, it is possible to perform a swelling process in order to widen the half width, but there is a problem that the control is difficult and the number of manufacturing steps is increased. further,
In order to avoid complementary colors, a reflection hologram exposed and manufactured at a plurality of wavelengths can be used.However, in this case, a light source emitting a plurality of exposure wavelengths is required at the time of manufacturing, so that manufacturing equipment is complicated. There was a disadvantage that it became expensive.

[0009]

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 room mirror used for confirming the rear, and a hologram is arranged on the opposite side of the glass plate from the reflection layer, and the hologram allows the rear image to be viewed toward the driver by the reflection layer. The present invention provides a room mirror, which is a hologram that transmits and diffracts a rear image toward the reflection layer at an installation angle different from a predetermined installation angle of the room mirror.

[0010]

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 transmission type 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. Outside. In this example, the inorganic glass plates 2 and 4 are 66 m wide.
m, length 270 mm, horizontal curvature R = 1500 mm
The two sheets were produced as a pair using a glass plate bending method usually used when producing 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 affixed to the surface of the glass plate 4 opposite to the reflection layer 5, and another glass plate 2 is laminated via an intervening 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 views 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 in which an anti-glare function of the room mirror of the present invention is obtained (in FIGS. 2 and 3,
In order to clarify the optical path, the hologram 1 is drawn with an increased thickness. ).

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 transmitted and diffracted at a diffraction angle β.
The hologram 1 diffracts the reflection layer 5 in conformity with the diffraction conditions.
Light that enters the eyes of the driver as light 18 reflected by the light is light from above (light having an incident angle α) as shown in the figure. Since this direction is usually the ceiling of the vehicle, it is hardly visible especially during night driving.

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 results, and the light 2 diffracted by the hologram 1 and reflected by the reflection layer 5
The image with 0 is visible. The remaining light transmitted through the hologram 1 is reflected by the reflection layer 5 on the back side of the glass plate.
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. Accordingly, 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 80 to 89 degrees with respect to the reflection layer in the vertical direction.

The hologram 1 used in this embodiment is a transmission hologram, in which both reference light and object light are collimated and exposed from both sides of the hologram material, and the incident angle α = 14.
Degrees and the diffraction angle β = 5 degrees.

The hologram is exposed at two wavelengths of 545n.
m dye laser light was irradiated from one side of the hologram material. 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. According to FIG. 4, since the hologram 1 has a wide band characteristic, the complementary color of the transmitted light does not matter.
Further, since the reflectance is lower than the reflection by the reflection layer 5, there is a light attenuation effect, and it 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 the characteristics shown in FIG. 4, and the effectiveness as an antiglare mirror was 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 suppressed to a minimum.

The hologram 1 of this embodiment is made of parallel light for both the reference light and the object light, and diffracts light only in the vertical direction. Therefore, 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-described curvature, the hologram was deformed following the glass plate, and the effect in the horizontal direction was almost equivalent to the effect of the convex surface due to the curvature of the glass plate. .

The hologram according to the present invention is a broadband transmission hologram exposed by light of a single wavelength as in the present embodiment, and can be subjected to multiple exposure with light of a plurality of wavelengths.
Since it is not necessary to form a laminated hologram in which a plurality of holograms exposed with light of one or more wavelengths are laminated, it is preferable from the viewpoint of ease of production. The efficiency and half width 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 hologram exposure and the hologram swelling process.

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 reflection layer may be on the intermediate film side, and a hologram may be attached thereon.

In addition, the structure of the laminated body is not limited to an inorganic glass plate, and a transparent substrate called a so-called resin glass is used, and a hologram is laminated on a transparent substrate and a transparent substrate or a transparent film with an adhesive or an adhesive. However, considering the performance and durability as a mirror, a laminated glass structure as in this example is preferable.

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

Further, a normal room 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 breaking, but it has a laminated glass structure. This also has the effect of preventing scattering.

Although the present invention relates to a rearview mirror, the present invention can be applied to a mirror expecting other similar effects, and can be used, for example, for a side mirror.

[0031]

According to the rearview mirror of the present invention, it is possible to provide not only the function of the convex mirror but also the antiglare function.

[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 used for 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: Diffracted and reflected by hologram Light reflected by layer 21: Viewer 26, 28: Light reflected by glass plate surface

Claims (4)

[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 opposite side, and the hologram reflects the rear image at an installation angle different from a predetermined installation angle of the room mirror where the rear image is viewed toward the driver by the reflection layer. A room mirror, which is a hologram that transmits and diffracts light toward a layer. 2. The room mirror according to claim 1, wherein said room mirror has a curved shape in a horizontal sectional direction. 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 slant angle of the diffraction grating inside the hologram is 80-89 with respect to the reflection layer of the mirror in the vertical direction.
The room mirror according to any one of claims 1 to 3, wherein the degree is a degree.