JPH06242307A - Optical reflecting element and optical reflector using the same - Google Patents

Abstract

PURPOSE:To obtain an optical reflecting element having high visibility and an optical reflector using the element at a comparatively low cost by utilizing a spherical lens or a cylindrical lens. CONSTITUTION:In the case of constituting an optical reflecting element 11 for reflecting incident light from the incident face side along the same route as an incident route of a semicircle-like spherical lens 12 in which the cross selections of a light incident face and an opposite face opposed to the incident face are respectively projected semicircle shapes and a reflecting face 15 arranged on a focal point on the opposite face side or its vicinity, the lens 12 is held by a holder 13 provided with a holding part 13a and pressed by a fixing member 14 fitted to the holder 13 to fix the lens 12 and the reflecting face 15 is arranged between the lens 12 and the holding part 13a of the holder 13. Consequently the practical optical reflecting 11 element can be inexpensively obtained by the simple structure. When a translucent spacer 16 is arranged between the reflecting face 15 and the lens 12, a required reflection characteristic can easily be obtained by adjusting the interval between the surface of the lens and the reflecting face 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical reflecting element in which an incident light ray is reflected along an incident path by using a spherical lens or a cylindrical lens, and an optical reflecting device in which the optical reflecting element is combined. .

[0002]

2. Description of the Related Art As a device for reflecting an incident light ray in the incident direction, a corner cube applying a right-angle prism is known, but it is expensive because it requires precision processing, and it is used for some special purposes. Only used. Further, as a general reflecting device, for example, there are a reflecting plate using a fluorescent paint and a reflecting plate having a reflecting surface provided with fine irregularities, but these have weak reflecting power. In particular, the performance of reflecting obliquely incident light rays in the incident direction is low, and it is difficult to obtain good visibility without being influenced by the viewing direction.

By the way, when a light ray is incident toward the center of a spherical lens having a refractive index of 2.0, it is focused on an antipodal surface that is point-symmetric with respect to the incident surface with respect to the center of the sphere, and is reflected here. It is known that the reflected light rays are reflected along the path of the incident light rays. When the refractive index is less than 2.0, the lens is focused on the outside of the lens, but in this case as well, the ray reflected at this focus is along the path of the incident ray as in the case where the refractive index is 2.0. Is reflected. This phenomenon is similarly established in a columnar lens such as a cylindrical lens in the radial direction perpendicular to the axis. However, hitherto, an optical reflection element that positively utilizes this phenomenon has not been developed.

[0004]

SUMMARY OF THE INVENTION The present invention pays attention to the above points and positively utilizes the above phenomenon in a spherical lens or a cylindrical lens to provide an optical reflection element having good visibility and an optical reflection element using the same. The object was to realize the device at a relatively low cost.

[0005]

In order to achieve the above-mentioned object, the optical reflecting element of the present invention is a lens in which the cross section of the light incident surface and the antipodal surface with respect to this light incident surface are semicircular in shape. And a reflection surface arranged at or near the focal point on the antipodal side, an optical reflection element that reflects the light ray incident from the incident surface side along the same path as the incident time is held. The above-mentioned lens is held by a holder provided with a portion, and the lens is fixed by being pressed by a fixing member attached to the holder, and a reflecting surface is arranged between the lens and the holding portion of the holder.

As the above-mentioned lens, a spherical lens, a cylindrical lens, a rod-shaped cylindrical lens, or a shape similar to these is used. In addition, a translucent spacer can be interposed between the reflective surface and the lens, and a colored portion may be formed on the reflective surface or the translucent spacer. A plurality of colored portions having different colors are formed. can do.

Further, the optical reflecting device of the present invention has a structure in which the above-mentioned optical reflecting elements are linearly or planarly or three-dimensionally arranged and attached to a supporting member.

[0008]

Since the lens is held and fixed by the holder and the fixing member attached to the holder, a practical optical reflecting element can be obtained at a low cost with a simple structure. Further, by interposing a translucent spacer between the reflective surface and the lens, it becomes easy to obtain a desired reflective characteristic by adjusting the distance between the lens surface and the reflective surface. Further, in the case where the colored part is formed, the reflected light has a color, and in the case where a plurality of colored parts are provided and the colors are different, the color of the reflected light changes depending on the viewing direction, so it is used for decoration and alerting. An optical reflection element suitable for is obtained.

Further, in the optical reflection device using the optical reflection element as described above, the reflected light returns in the incident direction of the light beam irrespective of the direction of the reflection surface, so that the laser light beam is emitted to the target installed at a distance, for example. It is useful as a monitor for detecting whether or not it is hit, and when it is used as a display device for decorations, advertisements, road signs, etc., excellent visibility with high visibility can be obtained. In particular, when used for road signs, work clothes, helmets, etc., the visibility of reflected light when illuminated by headlights at night is improved and safety is increased. Further, in the case where a plurality of colored portions are provided and the colors thereof are different, the color of the reflected light changes depending on the viewing direction, so that the decorativeness and the alerting power are improved.

[0010]

First, the optical principle will be described with reference to FIG. 1 before describing specific examples. In the figure, 1 is a spherical lens,
Denoted at 2 is a reflecting surface. If the center of the lens 1 is O, the radius is R, the refractive index is n _1, and the refractive index of the external space is n ₀ , the distance f from the center O of the lens 1 to the focal plane is f. = N ₁ R / {2 × (n ₁ −n ₀ )} (1), and the distance S from the surface of the lens 1 to the focal plane is given by S = f−R (2). The unit is mm. Further, this relationship is similarly established in the radial direction along the cross section perpendicular to the axis even if the lens 1 is not a spherical lens but a cylindrical lens.

For example, if n ₁ = 2.0 and n ₀ = 1.0, then f = R and S = 0, and the antipodal surface with respect to the incident surface, that is, the opposite point symmetrical with respect to the center O. The surface on the side becomes the focal plane. Further, if the refractive index n ₁ of the lens 1 is less than 2.0, the outer from the surface of the lens 1 is the focal plane becomes the distance S> 0. For example, if the material of the lens is normal glass and n ₁ = 1.5, then S = 5 mm for a lens of R = 10 mm, and the focal plane is 5 mm from the lens surface.

Therefore, in any case, if the reflecting surface 2 is arranged on this focal plane, the light ray incident so as to pass through the center O is
As illustrated as B ₁ , B ₂ , and B _{3 in the} figure, the light is reflected along each incident path regardless of the incident angle.
That is, all the light rays incident from the hemisphere on the incident surface side are reflected in the direction of the light source along the path when they are incident regardless of the incident direction, so that an optical reflective element with good visibility can be obtained. The distance S from the lens surface to the focal plane
The larger the value, the larger the overall size of the optical reflection element, so the refractive index is as close to 2.0 as possible, ideally 2.
It is preferably 0.

In FIG. 1, S ₁ , S ₂ and S ₃ are colored reflecting surfaces provided at the positions of the reflecting surface 2 where the light rays B ₁ , B ₂ and B ₃ are reflected, and the incident light rays are white. If it is a light ray, the reflected light reflected by these colored reflecting surfaces becomes colored, for example, the reflecting surface S ₁ is red, S ₂ is green, and S _{3 is}
Is blue, the reflected light of ray B ₁ is red, B ₂ is green,
B ₃ becomes blue, and the color of the reflected light changes depending on the incident direction of the light ray. Therefore, if the white light is emitted from various angles, the reflected light colored when the viewer comes on the optical axis will enter the eye, and the color will change depending on the position.

Even if the incident light is incident as an extremely thin parallel beam bundle, the reality is that the aberration of the lens, a slight displacement of the reflecting surface, or the focal position slightly differs depending on the wavelength of the light. The reflected light spreads a little.
However, for example, when the light is emitted from the headlights of an automobile, it is difficult for the light to be reflected only toward the headlights, and it is difficult for the driver to see the light. Since the visibility is improved, the spread of the reflected light slightly can be a preferable phenomenon.

FIG. 2 shows a concrete example, which is an example using a concave holder to which a hook structure used for clothes and the like is applied. In the figure, 11 is an optical reflection element, and 1
Reference numeral 2 is a spherical lens made of a transparent material such as glass or plastic, 13 is a concave holder, 14 is a pressing spring, 15 is a reflecting surface, and 16 is a translucent spacer. The holder 13 has a hemispherical holding portion 13a and a collar portion 13b, and a reflecting surface 15 is formed on the inner surface of the holding portion 13a.
A pressing spring 14 is attached to the collar portion 13b as a fixing member. The pressing spring 14 is shaped so as to slightly close the peripheral edge of the opening of the holding portion 13a, and the spherical lens 12 is fixed in the holding portion 13a by being pushed into the holding portion 13a against the spring 14. .

The translucent spacer 16 is inserted between the reflecting surface 15 and the spherical lens 12, and the lens surface and the reflecting surface 15 are inserted.
This is for locating the reflecting surface 15 on the focal plane of the spherical lens 12 while keeping a predetermined distance between the reflecting surface 15 and the spherical lens 12. The thickness of the reflecting surface 15 depends on the refractive index of the lens used and the above-mentioned formula (1) (2)
The size is selected according to the distance S from the lens surface to the focal plane that is derived from If the refractive index is 2.0, the focal plane coincides with the surface of the lens, so the thickness is 0, that is, the spacer 16 is unnecessary, but a lens with a refractive index of 2.0 is extremely expensive, Since a lens having an index of refraction of less than 2.0 is often used, a spacer 16 is generally required.

FIG. 3 shows an example of the spacer 16.
Reference numerals a and 16b are colored portions formed in part. This coloring part can be made different in color between 16a and 16b, and it may be formed in a larger number instead of two as shown in the figure, or may be entirely composed of several coloring parts without a colorless transparent part. It is also possible to use the one having the same colored portion as the whole. The spacer 16 having such a structure can be manufactured by, for example, multicolor molding of plastic,
When the spacer 16 is made of plastic, its elasticity also serves to protect the spherical lens 12.
The colored portion may be provided on the reflecting surface 15 without being provided on the spacer 16 as described above.

Reference numeral 17 is a small hole formed in the bottom of the holding portion 13a, and 18 is a small hole formed in the collar portion 13b.
Reference numeral 7 is for pushing up when the spherical lens 12 is taken out from the holder 13, and small hole 18 is for attaching when the holder 13 is attached to a support member such as cloth or plastic or metal.

FIG. 4 shows another embodiment in which the spherical lens 12 is inserted into the holding portion 13a of the holder 13 and the reflecting surface 15 and the spacer 16 are arranged between the holder 13 and the lens 12. The point is the same as the above-mentioned embodiment, but the lid 21 is used as a fixing member. That is, the lid 2
1 is provided with a holding hole 21a having a diameter slightly smaller than the opening of the holding portion 13a of the holder 13. By holding the spherical lens 12 at the peripheral edge of the hole 21a and fixing it to the collar portion 13b of the holder 13 with a screw 22. The optical reflection element 11 is configured. Therefore, in this embodiment, the spherical lens 12 can be taken out from the holder 13 by removing the lid 21, and the pushing-up small hole 17 in the embodiment of FIG. 2 is unnecessary. In this embodiment, the mounting small hole 18 includes the lid 21 and the collar portion 1.
It is provided so as to penetrate 3b.

The spacer 16 may be provided integrally with the holder 13 together with the reflecting surface 15, or conversely, it may be provided integrally with the spherical lens 12, and the reflecting surface 15 is also included in the spherical lens 12.
It is also possible to provide integrally with.

The optical reflection element 11 of the present invention is constructed as described above, and as shown in FIG. 5, a plurality of the optical reflection elements 11 constitute a display portion 26 for characters, figures, patterns, symbols and the like. By arranging, the optical reflection device 25 of the present invention is formed. The large number of optical reflection elements 11 utilize small holes 18 for attachment and are attached to a flat plate-shaped support frame 27 by appropriate means. In the example of FIG. 5, the optical reflecting elements 11 are two-dimensionally arranged in a plane, but one-dimensional linear arrangement or three-dimensional three-dimensional arrangement is free according to a desired character or figure. Is.

According to the optical reflecting device 25 having such a structure, since the light rays are reflected in the incident direction, an advertisement or a road sign having good visibility can be obtained. Further, by providing a colored portion on the reflecting surface 15 or the spacer 16 so that the reflected light is colored in a desired color, it is easy to further improve the visibility and enhance the decorative effect, and it is possible to increase the decorative effect depending on the position. If the color of the reflected light is changed, a further excellent effect can be expected. Since the optical reflection element 11 has a structure in which the lens can be easily attached and detached, when the lens surface or the like becomes dirty and the reflection intensity decreases, the lens 12 can be removed from the holder 13 and easily cleaned.

Although a spherical lens is used in each of the above embodiments, the lens is not limited to a spherical lens. For example, a cylindrical lens 12-1 or (b) shown in FIG. A columnar lens such as the two spherical rod type cylindrical lens 12-2 shown can also be used. In this case the holder 13
Is elongated, and the holding portion 13a is also formed in an elongated groove shape according to the shape of the lens. In this case, since the relation that the light rays are reflected in the incident direction is established only in the plane perpendicular to the axis, the posture and direction of the optical reflection element are restricted unlike the case of the spherical lens, but It can be used without any problem if it is placed in consideration. 2
In the case of the spherical rod type cylindrical lens 12-2, one semi-cylindrical portion is the incident surface side of the light beam, and the other semi-cylindrical portion is the reflection surface side, and the incident light ray passes through the center of the arc of each semi-cylindrical portion. Is the target.

Next, the two spherical rod type cylindrical lens 12-2.
The dimensional relationship of each part will be described with reference to FIG. As shown in the figure, the radius on the incident surface side and the reflection surface side of the lens is R ₁ ,
R ₂ , the center thereof is O ₁ and O ₂ , the length between both end surfaces on the incident surface side and the reflection surface side is d, and the distance from the end surface to the main surfaces H ₁ and H ₂ is h
₁ and h ₂ , the distance from the principal surface to the focal point is f, and the distances from the end surface to the focal point are S ₁ and S ₂ , the refractive index of the lens is n ₁ and the refractive index of the external space is n ₀ . The following equations hold. Therefore, since n ₀ = 1.0, for example, n ₁ =
2 spherical rod type cylindrical lens 12 using 1.5 material
In the case of -2, in order to design the focal plane to coincide with the lens end face with R ₁ = R ₂ = R, d = 3R should be set.

F = n₁n₀R₁R₂/ [(N₁-N₀) {n₁(R₁+ R₂)-(N₁-N₀) d}] h₁= N₀R₁d / {n₁(R₁+ R₂)-(N₁-N₀) d} h₂= N₀R₂d / {n₁(R₁+ R₂)-(N₁-N₀) d} S₁= F-h₁  = N₀R₁{n₁R₂-(N₁-N₀) d} / [(n₁-N₀) {n₁(R₁+ R₂)-(N ₁ -N₀) d}] S₂= F-h₂  = N₀R₂{n₁R₁-(N₁-N₀) d} / [(n₁-N₀) {n₁(R₁+ R₂)-(N ₁ -N₀) d}]

FIG. 8 shows an example of a lens provided with a collar 12a. In the case of a spherical lens, it surrounds the lens in a ring shape.
In the case of a columnar lens, the flanges 12a are formed in a rectangular shape so as to surround the lens. When the collar 12a is thus provided, the mounting posture of the lens with respect to the holder is specified, which is convenient, for example, when the reflecting surface and the spacer are integrally formed on the lens surface. If the refractive index is less than 2.0, a predetermined space is required between the lens surface and the reflecting surface. In the above embodiment, this space is secured by the spacer 16, but the spacer 16 is used. Instead, for example, a structure in which a stepped portion is formed on the lens 12 to secure the above-mentioned interval is possible. As described above, various shapes of lenses can be used, and when plastic is used as the material,
A well-known resin molding technique can be used to manufacture a lens having a complicated shape relatively easily and at low cost.

[0027]

As is apparent from the above-described embodiments, the optical reflecting element of the present invention uses a spherical lens or a cylindrical lens to reflect an incident light beam along the incident path, and the holding portion The holder is used to hold the lens, the fixing member attached to the holder presses the lens to fix the lens, and the reflecting surface is arranged between the lens and the holding portion.

Therefore, the structure is simple and the cleaning is easy when it becomes dirty, and it is possible to obtain a practical optical reflecting element with good visibility at low cost, and to provide a spacer between the reflecting surface and the lens. With the interposition, it becomes easy to obtain a desired reflection characteristic by adjusting the distance between the lens surface and the reflecting surface according to the refractive index of the lens. Also, in the case where a colored portion is formed on the reflective surface or the translucent spacer, the reflected light is colored, and in the case where a plurality of colored portions are provided and the colors are different, the color of the reflected light changes depending on the viewing direction. An optical reflection element suitable for applications such as decoration and alerting can be obtained.

Further, the optical reflection device using the optical reflection element of the present invention is useful as an irradiation monitor for a target at a remote place because the reflected light returns in the irradiation direction of the light beam regardless of the direction of the device. Further, when it is used as a display device for decorations, advertisements, road signs, etc., a device having excellent reflection performance and high visibility can be obtained. In particular, when used for road signs, work clothes, helmets, etc., the visibility of reflected light when illuminated by a headlight at night is improved and safety is enhanced. In addition, in the case where the colored portion is provided, the reflected light is colored, and in the case where a plurality of colored portions are provided and the color is different, the color of the reflected light changes depending on the viewing direction, which enables a unique display, The optical reflection device can be used for various purposes such as decoration, advertisement, and road signs.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the present invention.

2A and 2B are a plan view and a sectional view of an embodiment of the optical reflection element of the present invention.

FIG. 3 is a cross-sectional view of a spacer of the same example.

FIG. 4 is a plan view and a cross-sectional view of another embodiment.

FIG. 5 is a front view of an embodiment of the optical reflection device of the present invention.

FIG. 6 is a perspective view showing a shape of a lens used in the present invention.

FIG. 7 is an optical explanatory diagram of a lens used in the present invention.

FIG. 8 is a side view showing another example of the shape of the lens used in the present invention.

[Explanation of symbols]

 1, 12 Spherical lens 2, 15 Reflecting surface 11 Optical reflecting element 12-1, 12-2 Columnar lens 13 Holder 14 Holding spring 16 Spacer 16a, 16b Coloring part 21 Lid 25 Optical reflecting device 27 Support frame

Claims (7)

[Claims] 1. An incident surface of a ray of light and a lens whose cross section of the antipodal surface with respect to this incident surface is a semicircular shape having a convex shape, respectively, and a reflecting surface arranged at or near a focal point on the antipodal surface side. An optical reflection element that reflects light rays incident from the surface side along the same path as when incident, holding the lens with a holder equipped with a holding portion, and pressing it with a fixing member attached to the holder. An optical reflecting element, characterized in that the lens is fixed and a reflecting surface is arranged between the lens and the holder of the holder. 2. The optical reflection element according to claim 1, wherein the lens is a spherical lens or a shape similar thereto. 3. The lens is a cylindrical lens, a rod-shaped cylindrical lens, or a shape conforming to these.
The optical reflection element described. 4. The optical reflection element according to claim 2, wherein a translucent spacer is interposed between the reflection surface and the lens. 5. The optical reflection element according to claim 4, wherein a colored portion is formed on the reflection surface or the translucent spacer. 6. The optical reflection element according to claim 5, wherein a plurality of colored portions having different colors are formed. 7. An optical reflection device comprising the optical reflection element according to any one of claims 4 to 6 linearly or planarly or three-dimensionally arranged and attached to a support member.