JPH08258624A - Rear-view mirror - Google Patents

Abstract

PURPOSE: To vary the viewing range of a mirror without mechanical handling by reflecting the light from the rear view field condensed by a liquid crystal lens by a specular element into the car body, impressing a voltage on a liquid crystal layer using a voltage impressing means, and varying the voltage using a voltage changing means. CONSTITUTION: A liquid crystal lens 15 to take in a beam of incident light 13 from the rear view field is furnished on a easing 14, and a concave mirror 16 is provided as a specular surface to which the fed light is put incident within the view field. The liquid crystal lens 15 is a laminate consisting of a polarizing film 21, base board 22 of glass, the first ITO film 23, the first photo-orientation film 24, the first nematic liquid crystal 25, the second photo-orientation film 26, the second ITO film 27, and a lens 28. An inverter 41 is connected with the ITO films 23, 27, and the DC voltage of a DC power supply 43 is converted into AC voltage, and the voltage value is transformed by a voltage changing part 42. Because the transmission ratio of the first nematic liquid crystal 25 for normal beams of light relative to abnormal varies according to the size of the impressed AC voltage, the focal distance of the liquid crystal lens 15 changes to cause a change of the rear view field.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rearview mirror mounted on a vehicle body, and more particularly to a rearview mirror having a rear view range variable.

[0002]

2. Description of the Related Art In general, rearview mirrors such as door mirrors are attached to left and right front side portions of a vehicle body so as to visually recognize the rear side. In such a vehicle rearview mirror, in recent years, a rearview mirror capable of varying a rear visual field when viewed from a driver is being developed. This is to improve safety by eliminating blind spots when the driver confirms the rear when changing lanes or making a right turn. As such a rearview mirror whose field-of-view range can be changed, a conventional rear-view mirror is used.
No. 148541 micro film (hereinafter referred to as conventional example 1), Sekikaihei 2-133938 micro film (hereinafter referred to as conventional example 2), Sekikaihei 4-42443 micro film (hereinafter referred to as conventional example 3), and the like. What has been done is known.

FIG. 4 is an explanatory view showing the contents disclosed in Conventional Example 1. As shown in the drawing, in the conventional example 1, the support tool 2 attached to the inner side surface of the casing 1
The shaft 3 is inserted through the opening. One end of the shaft 3 is fixed to a support rod 5 protruding from the end of the flexible mirror 4, and a metallic stopper 6 is attached to the other end. Further, an electromagnet 7 is arranged at a predetermined distance from the stopper 6, and when a current is passed through the electromagnet 7, the stopper 6 is attracted to the electromagnet 7 side by a magnetic attraction force. As a result, the shaft 3 slides, and as a result, the mirror 4 bends inward of the casing 1, which widens the rear visual field from the driver and facilitates the rear visual recognition.

[0004]

However, in the rearview mirrors of the conventional examples 1 and 2 and 3 as described above, since the mirrors are mechanically curved, the mechanism for changing the field of view becomes complicated. However, the entire casing becomes large. Further, since the mirror is curved, there is a drawback that the curved angle may change due to a change with time, and it becomes impossible to always obtain a constant curvature. Further, since troubles such as peeling of the mirror may occur due to aging, maintenance and the like are frequently required. The present invention has been made to solve such a conventional problem, and an object of the present invention is to provide a rearview mirror capable of varying the field of view of the mirror without requiring mechanical operation. To provide.

[0005]

In order to achieve the above object, the present invention is a rear-view rearview mirror that is mounted so as to project to the outermost side of the vehicle on the side of the vehicle body and that can be viewed normally from the rear by the applied voltage value. A liquid crystal lens that has a liquid crystal layer in which the transmission ratio between light rays and extraordinary rays changes, and that collects light that enters from within the rear visual field range; and a mirror surface that reflects the light that is condensed by the liquid crystal lens to the inside of the vehicle. It is characterized in that it has a body, a voltage applying means for applying a voltage to the liquid crystal layer, and a voltage varying means for changing the applied voltage.

[0006]

According to the present invention constructed as described above, by applying a voltage to the transparent electrodes provided on both sides of the liquid crystal layer of the liquid crystal lens, the ratio between the extraordinary ray and the ordinary ray transmitted through the liquid crystal lens is determined. It is variable. Since the extraordinary ray and the ordinary ray have different refractive indexes, the refractive index can be changed according to the magnitude of the applied voltage, and as a result, the rear visual field of the rearview mirror can be changed. .

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a schematic configuration of a rearview mirror to which the present invention is applied. As shown in the figure, the rearview mirror 12 is formed so as to project from the vehicle body 11 at the outermost portion of the vehicle and is surrounded by a casing 14. A liquid crystal lens 15 for taking in incident light 13 from the rear visual field is provided on the rear side of the casing 14.
Is installed, and a concave mirror 16 as a mirror surface for reflecting the light to enter the visual field of a driver (not shown) inside the vehicle body is arranged on the path of the light taken in from the liquid crystal lens 15. It is set up.

FIG. 2 is a sectional view showing a laminated structure of the liquid crystal lens 15 according to the first embodiment of the present invention. As shown in the figure, the liquid crystal lens 15 is formed by laminating a plurality of layers, and the polarizing film 21, the glass substrate 22, and the first ITO film 23 are arranged in the direction of entrance of incident light shown by the arrow in the figure. , First
The alignment film 24, the first nematic liquid crystal 25, the second alignment film 26, the second ITO film 27, and the lens 28 are laminated in this order. The liquid crystal lens 15 has a refractive index between the first nematic liquid crystal 25 and the lens 28, and
The curvature of the lens 28 serves as a concave lens as a whole.

The polarizing film 21 is composed of a linear polarizer that linearly polarizes the incident light. First and second IT
The O (indium-tin-oxide) films 23 and 27 are transparent conductive films, and an inverter 41 is connected to each of the ITO films 23 and 27 so that an AC voltage is applied.
The inverter 41 is a DC power source 4 installed in the vehicle.
The DC voltage of No. 3 is converted into an AC voltage, and the voltage value at this time can be changed by the voltage changing unit 42. The first and second alignment films 24 and 26 are made of polyimide or the like and can align the rubbing direction and the long axis direction of the molecules of the nematic liquid crystal 25. The first nematic liquid crystal 25 is
The transmission ratio between the ordinary ray and the extraordinary ray changes depending on the magnitude of the applied AC voltage, and the focal length of the liquid crystal lens 15 changes accordingly. Further, reference numeral 29 is a spacer.
The major axis (optical axis) of the first nematic liquid crystal 25 and the polarization direction of the polarizing film 21 are arranged in parallel.

Next, the operation of this embodiment will be described.
Now, the voltage variable unit 42 is operated to operate the first and second ITO.
When an AC voltage VA is applied between the films 23 and 27 such that the long axis of the liquid crystal is oriented in the direction of the electric field, the incident light entering from the rear side of the vehicle body becomes linearly polarized light in the polarizing film 21, and in the nematic liquid crystal 25, the liquid crystal is oriented. On the other hand, only ordinary rays pass through the liquid crystal lens 15. The focal length of the liquid crystal lens 15 at this time is set to f0. Then, when the voltage varying unit 42 is adjusted to set the voltage VA to 0, the incident light is also linearly polarized by the polarizing film 21, and in the nematic liquid crystal 25, only an extraordinary ray with respect to the orientation of the liquid crystal becomes a liquid crystal lens. 15
Pass through. The focal length of the liquid crystal lens 15 at this time is f
Let be e. That is, when the voltage VA is applied, only the ordinary ray is transmitted, and when the voltage is 0, only the extraordinary ray is transmitted. Here, since the ordinary ray and the extraordinary ray have different refractive indexes of the nematic liquid crystal 25, the focal length of the liquid crystal lens 15 changes depending on whether or not a voltage is applied. Therefore, the visual field range can be changed depending on whether or not a voltage is applied. In addition, the applied voltage V has an intermediate value,
That is, when “0 <V <VA”, the composite wave of the ordinary ray and the extraordinary ray passes through the nematic liquid crystal 25, and the focal length f becomes “fe <f <f0” according to the value of the voltage V. The focal length of the rearview mirror can be continuously changed by continuously adjusting the voltage value with the voltage changing unit 42. Therefore, the rear visual field range can be continuously changed by adjusting the voltage.

Thus, according to this embodiment, the IT
The focal length of the nematic liquid crystal 25 changes depending on the magnitude of the AC voltage applied to the O films 23 and 27.
The field of view of the rearview mirror can be made variable. Therefore, unlike the related art, a complicated mechanism such as mechanically bending a mirror is not required, and the field of view can be easily changed only by adjusting the applied voltage. Further, since the voltage value can be continuously changed, the field of view can be adjusted steplessly, and a suitable field of view can be selected and adjusted according to the driving situation.

Further, since the number of parts is smaller than that of the conventional one, it becomes possible to achieve miniaturization and space saving. Further, the lens 28 has a polarization selecting action and thus has an antiglare function. Therefore, glare can be reduced. In the first embodiment, the polarizing film 2
Although the linear polarizer is used as 1, the axially symmetric polarizer may be used as a modification. In this case, the nematic liquid crystal 25 is oriented in axial symmetry (concentric circles). As a specific axisymmetric polarizer, an axisymmetric polarizing plate having a structure in which one surface of a flat liquid crystal cell is unidirectionally rubbed and the other surface is concentrically rubbed is known. Even in such a configuration, the above-mentioned first
As in the embodiment, the rear visual field can be made variable by applying an AC voltage between the first and second ITO films 23 and 27. Further, in this modification, since the axially symmetric polarizer is used, astigmatism can be reduced, and defocusing of the rearview mirror can be reduced.

FIG. 3 is an explanatory view showing a cross section of a liquid crystal lens according to a second embodiment of the present invention. As shown in the figure, in this embodiment, instead of the polarizing film 21 shown in FIG. 2 of the first embodiment, a third ITO film 30, a third alignment film 31, a second nematic film are used. A layer including the liquid crystal 32, the fourth alignment film 33, the fourth ITO film 34, and the lens 35 (hereinafter, this layer is referred to as an A layer, and the layers including reference numerals 23 to 28 is referred to as a B layer) is formed, and the polarizing film is formed. 21 is different from the first embodiment in that the same function as 21 is performed. At this time, the first nematic liquid crystal 25 and the second nematic liquid crystal 32 are arranged so that the liquid crystal orientations are orthogonal to each other. Also,
An alternating current from the inverter is also supplied between the third ITO film 30 of the A layer and the fourth ITO film 34 similarly to the B layer.

The operation of the second embodiment thus constructed will be described below. By operating the inverter 41 and adjusting the voltage variable portion 42, the ITO films 23 and 2 of the A layer and the B layer are adjusted.
When an AC voltage VA is applied between 7 and 30, 34, the incident light becomes an ordinary ray with respect to the orientation of the nematic liquid crystals 25, 32 of the A layer and the B layer and passes through the liquid crystal lens. Therefore, the focal length at this time is f0. Further, when the applied AC voltage is 0, the light incident from the rear visual field is separated into the ordinary ray and the extraordinary ray by the birefringence in the A layer, the ordinary ray becomes the extraordinary ray in the B layer, and the extraordinary ray passes as it is. Therefore, as a result, the total transmitted light is only extraordinary rays. Therefore, the focal length at this time is fe. Then, as in the case of the first embodiment described above, if the applied voltage value is changed in the range of 0 to VA, the combined wave of the extraordinary ray and the ordinary ray passes through the liquid crystal lens, so that the focal length is stepless. It will be adjustable.

In this way, in the second embodiment,
Instead of the polarizing film 21 shown in the first embodiment, a third I
Since the A layer including the TO film 30 to the lens 35 is used, the same effect as that of the first embodiment can be obtained, and further, the polarizing film 2
1, the light transmittance of the polarizing film is usually 30 to
Since it is about 40%, the rear side can be visually recognized with a sufficient light amount without lowering the light transmittance. Next, a third embodiment of the present invention will be described. Although the linearly polarized nematic liquid crystal is used in the second embodiment described above, it is also possible to use the axially symmetrical polarized nematic liquid crystal, which will be described below with reference to FIG.

In this embodiment, the second nematic liquid crystal 32 of the layer A shown in FIG. 3 is changed from the one-concave surface shape to the planar shape, and the nematic liquid crystal 32a having the planar shape is used.
Accordingly, the fourth alignment film 33a and the lens 35a also have a planar structure. However, the lens 35a may be a glass substrate. In addition, as compared with FIG. 3, the third and fourth ITO films 3
0 and 34 are not arranged, and therefore, the power from the inverter 41 is not supplied to the A layer.

Further, the incident surface side of the second nematic liquid crystal 32a is unidirectionally rubbed, and the opposite surface side is axisymmetrically rubbed, and both sides of the first nematic liquid crystal 25 are axisymmetrically rubbed. There is. According to this structure, the A layer functions as an axially symmetric polarizer, and the light incident on the A layer is axially symmetric polarized and then incident on the B layer. As described above, since the B nematic liquid crystal 25 is axisymmetrically rubbed, the focal length can be changed according to the magnitude of the voltage from the inverter 41 as in the second embodiment. Further, in the third embodiment, since the layer A is axisymmetrically polarized, the above-mentioned first
Astigmatism can be reduced in the same manner as in the modified example of the embodiment, so that the defocusing of the rearview mirror can be reduced. In the first to third embodiments, the light condensed by the liquid crystal lens 15 is reflected in the direction of the driver's visual field by using the concave mirror which is a specular body. However, the present invention is not limited to this. Instead, a flat mirror or a convex mirror may be used.

[0018]

As described above, according to the present invention,
The light from the rear visual field of the vehicle body is condensed by a liquid crystal lens having a liquid crystal layer in which the transmission ratio between the ordinary ray and the extraordinary ray changes according to the applied voltage value. Therefore, the refractive index can be made variable by adjusting the voltage, and the rear visual field can be arbitrarily changed. Therefore, it becomes possible to easily select the rear view according to the traveling speed and the traffic situation. In addition, it does not require operations such as mechanically bending the mirror as in the past,
It is possible to solve the problem caused by the change over time such as the structure being simplified and the mirror peeling. Further, if an axially symmetric polarizer is used as the polarization means, astigmatism can be reduced, and the effect of reducing the defocus of the rearview mirror can be obtained.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a rearview mirror to which the present invention is applied.

FIG. 2 is a sectional view showing a laminated structure of the liquid crystal lens according to the first embodiment of the present invention.

FIG. 3 is a sectional view showing a laminated structure of a liquid crystal lens according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a laminated structure of a liquid crystal lens according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram showing a conventional example.

[Explanation of symbols]

11 vehicle body 12 rearview mirror 13 incident light
14 casing 15 liquid crystal lens 16 concave mirror 21 polarizing film
22 Glass Substrate 23 First ITO Film 24 First Alignment Film 25 First Nematic Liquid Crystal 26 Second Alignment Film 27 Second ITO Film 28 Lens 29 Spacer 30 Third ITO Film 31, 31a Third Alignment Membrane 32, 32a Second nematic liquid crystal 33, 33
a fourth alignment film 34 fourth ITO film 35, 35a lens 41 inverter 42 voltage variable unit 43 DC power supply

[Procedure amendment]

[Submission date] April 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The polarizing film 21 is composed of a linear polarizer that linearly polarizes the incident light. First and second IT
O (indium-tin-oxide) films 23 and 27
Is a transparent conductive film, and an inverter 41 is connected to each of the ITO films 23 and 27 so that an AC voltage is applied. The inverter 41 converts the DC voltage of the DC power supply 43 mounted in the vehicle into an AC voltage, and the voltage value at this time can be changed by the voltage variable unit 42.
The first and second alignment films 24 and 26 are made of polyimide or the like and can align the rubbing direction and the long axis direction of the molecules of the nematic liquid crystal 25. In the first nematic liquid crystal 25, the transmission ratio between the ordinary ray and the extraordinary ray changes depending on the magnitude of the applied AC voltage, and the focal length of the liquid crystal lens 15 changes accordingly. Further, reference numeral 29 is a spacer. The first nematic liquid crystal 25
The long axis (optical axis) and the polarization direction of the polarizing film 21 are arranged in parallel.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

In this embodiment, the second nematic liquid crystal 32 of the layer A shown in FIG. 3 is changed from the one-concave surface shape to the planar shape, and the nematic liquid crystal 32a having the planar shape is used.
Accordingly, the fourth alignment film 33a and the lens 35a also have a planar structure. The lens 35a may be a glass substrate. In addition, as compared with FIG. 3, the third and fourth ITO films 3
0 and 34 are not arranged, and therefore, the power from the inverter 41 is not supplied to the A layer. ─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] February 29, 1996

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a vehicle rearview mirror to which the present invention is applied.
It is explanatory drawing which shows the structure of one Example . As shown in the figure, on the back side of the Cr rear surface mirror 1 as a mirror surface for rearward visual recognition,
Water is applied to the Cr rear surface mirror 1 to cause water drops, mist,
A mirror heater 2 for removing frost and the like is attached.
The mirror heater 2 is turned on.
Connected to a switching device 3 for controlling the on / off,
The switching device 3 is a road guidance system as an information input means.
It is connected to the system 4 and the power supply 5.

Claims (4)

[Claims] 1. A rear-view rearview mirror, which is attached to a vehicle outer side of a vehicle body side portion so as to project rearward, wherein a liquid crystal layer in which a transmission ratio between an ordinary ray and an extraordinary ray changes depending on a voltage value applied. A liquid crystal lens for condensing light incident from within the rear visual field range, a mirror body for reflecting the light condensed by the liquid crystal lens to the inside of the vehicle, and a voltage applying means for applying a voltage to the liquid crystal layer And a voltage changing means for changing the applied voltage. 2. The liquid crystal lens, a polarizing means for linearly or axisymmetrically polarizing incident light, a glass substrate, a first transparent conductive film, a first alignment film, and a first nematic liquid crystal layer. And a second alignment film, a second transparent conductive film, and a lens are laminated, and the voltage applying unit is provided between the first transparent conductive film and the second transparent conductive film. The rearview mirror according to claim 1, wherein a voltage is applied. 3. The polarizing means comprises a third transparent conductive film,
The third alignment film, the second nematic liquid crystal layer, the fourth alignment film, the fourth transparent conductive film, and the lens are laminated, and the second nematic liquid crystal is axially symmetric. Alignment or an arrangement in which the alignment is orthogonal to that of the first nematic liquid crystal, and the voltage applying means also applies a voltage between the third transparent conductive film and the fourth transparent conductive film. The rearview mirror according to claim 2. 4. The rearview mirror according to claim 1, wherein the voltage applying unit is an inverter that converts a DC voltage from a battery mounted in the vehicle into an AC voltage.