JPH078801U - Anti-reflection type Fresnel lens - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an anti-reflection type Fresnel lens that is effective in reducing visual interference, protecting privacy, and improving visibility. [Structure] The angle βn of the B surface of the lens element portion 2 of the Fresnel lens 1 is related to the mounting angle θ of the mounting surface 5 of the Fresnel lens 1 and the line-of-sight angle αn of the viewpoint (EP), and θ ≦ β
It is formed within the range of n ≦ θ + αn to secure the field of view of the line of sight 12n, and eliminates the reflection of incident light to the EP side to reduce the field of view obstruction. Further, a reflection material and / or an absorption material (not shown) are provided on the surface B to protect privacy and improve visibility. [Effects] The problem of the visual field obstruction of the conventional Fresnel lens is solved to secure the visual field, and the visibility from the outside into the room is reduced to protect the privacy. In addition, the incident light from the outside is reflected to improve the visibility and contribute to the advertising effect.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a Fresnel lens that is integrally mounted on the glass of an automobile or the like, and in particular, it is an antireflection Fresnel lens that is suitable for protecting the privacy of the occupant and the obstruction of the field of view due to reflection on the viewpoint side or the blurring of the field of view. Regarding the lens.

[0002]

[Prior art]

 As shown in FIG. 7, the Fresnel lens 1a is made of a narrow transparent lens, and a peak point (indicated by a) and a valley point (indicated by b) are connected to the opposite side of the flat mounting surface 5. A plurality of saw-tooth-shaped lens element portions 2a alternately forming a front side inclined surface (referred to as A surface) and a rear side inclined surface (referred to as B surface) are formed adjacent to each other. Widely used in. The Fresnel lens 1a is used at various places, but as shown in FIG. 8, the Fresnel lens 1a is integrally formed above and below a windshield 4 of a cab 3 of an automobile, for example. As shown in FIG. 7, the mounting surface 5 is mounted at a mounting angle θ. As shown, a part of the incident light 6 from the viewpoint (shown by EP) side is refracted at the A surface of the lens element portion 2a, reflected at the mounting surface 5, and further reflected at the B surface of the lens element portion 2a. Then, it becomes reflected light 7 and returns to the EP side. A part of the incident light 8 from the mounting surface 5 side is refracted by the mounting surface 5 of the Fresnel lens 1a, reflected by the B surface of the lens element portion 2a, and enters as reflected light 9 on the EP side. In any case, the reflected lights 7 and 9 hinder the view on the EP side, which is very dangerous.

FIG. 9 shows a cross section taken along the line CC of FIG. 8. The windshield 4 has Fresnel lenses 1a, 1a arranged vertically, and a resin plate 10 for preventing breakage formed in the middle thereof. Is integrally contained in the glass body 11. Of course, there is also one in which a separate Fresnel lens 1a is fixed to the back surface of the glass plate or the like. As described above, in the case of the conventional Fresnel lens 1a, since there is a visual field obstruction due to the reflected light 7, 9 etc., a portion where the Fresnel lens 1a is not formed (the portion of the resin plate 10 in FIG. 9) is formed to ensure safety and visual field. I am trying to However, when only the Fresnel lens 1a is used, the above-mentioned visual field obstruction occurs, which is a big problem in using the Fresnel lens.

On the other hand, there are many known techniques related to Fresnel lenses, for example, Japanese Utility Model Laid-Open No. 58-18201, Japanese Utility Model Laid-Open No. 63-125802, Japanese Patent Laid-Open No. 61-158367 and Japanese Patent Laid-Open No. 62-11803. Issued bulletins are listed.

The “Fresnel lens” in Japanese Utility Model Laid-Open No. 58-18201 has a light-shielding layer that absorbs light formed on the surface of the Fresnel lens that is refracted in a direction in which incident light is diffused. . In order to improve the luminance distribution of the screen of the television, a light-shielding layer is provided on the above-mentioned surface which causes a deterioration in image quality so as to absorb incident light. The "Fresnel lens" disclosed in Japanese Utility Model Laid-Open No. 63-125802 is a stepped surface between lens portions (between lens element portions) of the Fresnel lens or a portion of the other surface of the lens corresponding to the stepped surface and incident light on the stepped surface. It has a barrier layer or a diffusion layer. In order to prevent the deterioration of the image quality of the projected image on the screen surface, the light incident on the step surface between the lens parts is reflected or absorbed by the blocking layer or diffused by the diffusion layer to cut a part of the incident light. Is. The "illuminator" of JP-A-61-158367 has a linear Fresnel prism plate and a plane mirror arranged at an acute angle, and a tubular light source is installed on the opening side. This is to make the display uniform and eliminate unevenness in brightness on the display surface. Further, the "light-deflecting window glass plate" of Japanese Patent Laid-Open No. 62-11803 has a large number of light-deflecting bodies which are parallel to each other and constitute a part of a linear concave lens on a transparent window glass. A plurality of optical deflectors forming a part of a linear convex lens are provided in parallel in the lower part of the window glass, and the central part of the window is formed in a plain manner. The light entering the room through the window is deflected in a desired direction, and the light can be taken while protecting the privacy inside and outside the room.

[0006]

[Problems to be solved by the device]

 The above-mentioned publicly known technologies have their respective characteristics, and as described above, they are effective in obstructing the field of view and protecting privacy. However, none of these publicly known technologies have examined the angular shape of the saw blade of the Fresnel lens itself, and have not touched on the point of correcting the distortion of the field of view. There is nothing that prevents unwanted light rays from entering the EP side.

The present invention solves the above-mentioned problems, and eliminates the obstruction of the visual field by a relatively simple means for specifying the angular shape of the Fresnel lens, improves the safety, and protects the privacy. It is an object of the present invention to provide an antireflection type Fresnel lens having the above structure.

[0008]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention forms a large number of saw blade-shaped lens element parts, which are alternately connected with peaks and valleys, on the opposite side of a flat mounting surface along the longitudinal direction. A transparent Fresnel lens mounted on glass of a vehicle or the like, where the inclination angle between the horizontal line of sight line connecting the viewpoint and the valley point is αn, and the mounting angle of the mounting surface is θ, An antireflection Fresnel lens is constructed so that the angle βn of intersection between the inclined surface on the back side of the lens element portion connecting the point and the valley point and the orthogonal line of the mounting surface satisfies the relationship of θ ≦ βn ≦ θ + αn. is there. Further, the invention is characterized by an antireflection type Fresnel lens for protecting privacy by providing a light ray reflector and / or absorber on the inclined surface on the back side of the lens element section to reflect or absorb unnecessary rays and remove them. It is a thing.

[0009]

[Action]

 Reflection from the EP side and the outside by forming the inclined surface on the back side of the lens element part of the Fresnel lens mounted at the attachment angle θ so as to satisfy θ ≦ βn ≦ θ + αn in association with the line of sight of the inclination angle αn on the EP side. The direction of the light does not go to the EP side, and the obstruction of visibility is reduced. Further, by forming the angle βn within the above range, the overlap of the lenses seen from the EP side is reduced and the field of view is secured. Further, by providing a reflecting material and / or an absorbing material on the inclined surface, it is possible to secure the visibility from the EP side and protect the privacy from the outside. As described above, it is possible to solve the conventional problem of the visual field obstruction while securing the field of view, by a relatively simple means only by devising the shape of the Fresnel lens.

[0010]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings. 1 and 2 are partially sectional views showing the lens element portion 2 of the Fresnel lens 1 of this embodiment in an enlarged scale, and FIGS. 3 and 4 are for explaining the theoretical basis of the angular shape of the lens element portion 2. FIG. 5 is a partial sectional view of the Fresnel lens of the present embodiment, FIG. 6 is a partial sectional view for explaining the operation of the present embodiment, and FIGS. 11 and 12 show a reflecting material or an absorbing material. It is drawing which shows the provided Fresnel lens.

As shown in FIGS. 1 and 2, the lens element portion 2 of the Fresnel lens 1 and the flat mounting surface 5 on the opposite side are mounted on glass of a vehicle (not shown) at a mounting angle θ. Let αn be the inclination angle between the horizontal line of the line of sight 12n connecting the viewpoint EP inside the vehicle and the point b of the lens element portion 2, and βn be the angle of intersection between the orthogonal line 19 of the mounting surface 5 and the B surface. The surface B of the lens element portion 2 of the Fresnel lens 1 is formed so that θ ≦ βn ≦ θ + αn in relation to the EP and the mounting surface 5. 1 shows the case of βn = θ when αn = 0, and FIG. 2 shows the case of βn = θ + αn. The value of the angle βn of the B surface between θ and θ + αn can be theoretically and experimentally determined according to the arrangement of the Fresnel lens 1 and the intended use.

FIG. 3 is an enlarged view of the case where βn <θ. In the case of FIG. 1, the sight line 12 from the EP coincides with the B surface of the lens element portion 2, and the sight line 12 passes through the points a and b of the lens element portion 2. On the other hand, as shown in FIG. 3, in the case of βn <θ, the line of sight from the EP looking at the point a and the line of sight looking at the point b from the EP are different and are the line of sight 12a and 12b, respectively. As a result, the lenses are overlapped with each other between the lines of sight 12a and 12b (hatched portion in the figure), and the view is obstructed accordingly. Then, in the case of βn <θ, as shown in FIG. 3, the incident light from the outside of the mounting surface 5 is reflected by the B surface and is incident on the EP side as reflected light to cause a visual disturbance. Further, in the case of FIG. 2, the line of sight 12n at the angle αn passes through the points a and b of the lens element portion 2, but in the case of βn> θ + αn in FIG. The viewing line of sight 12 nb is different, and the part sandwiched by both lines (hatched portion in the figure) is interposed between the adjacent A faces. Adjacent surfaces A are sequentially connected to compose a lens surface, and the portion sandwiched by the lines of sight 12na and 12nb enters the lens surface to be composited as a so-called obstacle and causes a visual field obstruction. From the above, the value of βn is set in the range of θ ≦ β n ≦ θ + αn in this embodiment. FIG. 5 shows a change in the angle βn of the B surface of the Fresnel lens 1 of this embodiment, and the value of βn changes corresponding to the mounting position.

As shown in FIG. 6, in the case of the Fresnel lens 1 of the present embodiment, a part of the incident light 6 from the EP is refracted at the A surface of the lens element portion 2, reflected at the mounting surface 5, and the B surface. Is further reflected to become reflected light 7, but the reflected light 7 is directed away from the EP side by forming the B surface at the angle βn. Further, a part of the incident light 8 from the outside is reflected on the B surface to become reflected light 9, but the reflected light 9 also does not face the EP side as shown in the figure. As described above, the visual disturbance due to the reflected light is greatly reduced compared to the conventional one. FIGS. 1 and 2 show the case of βn = θ and βn = θ + αn. However, even when the value of the angle βn is set between θ and θ + αn, there is a difference between the A surface and the A surface as in the case of FIG. The B surface is not exposed in the meantime, and the visual field obstruction is reduced, and the incident light from the mounting surface 5 is reflected in the direction away from EP on the B surface and does not obstruct the visual field.

FIG. 10 shows a case where the Fresnel lens 1 of this embodiment is adopted as a part of the windshield 4 of the cab 3 of the vehicle. As shown in the drawing, a part of the line of sight 14 of the occupant 13 in the cab refracts inside the Fresnel lens 1 and faces, for example, the lower side of the external object 15. Therefore, the external object 15 can be fully visually observed. However, a part of the line of sight 16 from the external object 15 may be refracted in the Fresnel lens 1 and may face the feet of the occupant 13. Therefore, the lower half of the occupant may be visually inspected from the outside, which may violate the privacy protection of the occupant.

FIG. 11 and FIG. 12 show an embodiment for protecting the privacy of an occupant when the Fresnel lens 1 of this embodiment is used for the windshield 4, and a reflection material is provided on the B surface of the Fresnel lens 1. And / or the absorber 17 is provided. The reflection material and / or the absorption material 17 may be applied, or the printed matter may be adhered. Alternatively, the B-side may be a hologram surface or a mirror surface, or the line of sight 16 may be reflected or absorbed by other means. Further, only the reflecting material 17 or the absorbing material 17 may be provided on the B surface, or both may be used in combination.

As shown in FIGS. 11 and 12, the line of sight 14 from the EP side can pass through the Fresnel lens 1 to see the outside, but the line of sight 16 from the outside or incident light is reflected by the reflection material 17 on the B surface. The reflected light 18 becomes reflected light 18 and is reflected outward. Further, when the absorber 17 is used, incident light is absorbed by the absorber 17. Therefore, as shown in FIG. 10, the lower half of the occupant 13 cannot be seen from the outside, and the occupant's privacy is protected. Further, by using the reflecting material 17 or the absorbing material 17 on the B side, the light incident from the outside into the vehicle at night is reduced, and the safety of the vehicle operation is secured. In addition, the visibility can be enhanced during night parking. Also, advertisements, marks, etc. can be provided on the B side of the Fresnel lens 1 by printing or the like to enhance the advertising effect.

In the above description, the case where the Fresnel lens 1 of the present embodiment is applied to the windshield 4 of the vehicle has been described, but the object is not limited to the vehicle, and is also applied to optical devices.

[0018]

[Effect of device]

 According to the present invention, the following remarkable effects are obtained. 1) By forming the angle βn of the B surface of the lens element portion of the Fresnel lens within the range of θ ≦ βn ≦ θ + αn, the reflected light that obstructs the field of view is greatly reduced, and safety is secured. . 2) Since the interference of visibility is reduced, it can be used even in the parts where the Fresnel lens could not be used in the past, so the application can be expanded. 3) Especially when used for transportation equipment, the safety of operation can be improved and the privacy of passengers can be protected. 4) The visibility from the outside can be enhanced because it reflects without entering the room. Also, by providing advertisements, marks, etc. on the B side, the advertising effect can be improved. 5) It has a simple structure that devises the angular shape of the lens element portion, and can be implemented easily and at a relatively low cost.

[Brief description of drawings]

FIG. 1 is a partial sectional view of an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of this embodiment.

FIG. 3 is a partially enlarged cross-sectional view for explaining the theoretical basis of the angle βn of the B surface of the lens element portion.

FIG. 4 is a partially enlarged cross-sectional view for explaining the theoretical basis of the angle βn of the B surface of the lens element portion.

FIG. 5 is a partial cross-sectional view of the Fresnel lens of this embodiment.

FIG. 6 is a partial cross-sectional view for explaining the operation of this embodiment.

FIG. 7 is a partial cross-sectional view for explaining the problems of the conventional Fresnel lens.

FIG. 8 is a perspective view showing a cab equipped with a Fresnel lens.

9 is an enlarged sectional view taken along the line CC of FIG.

FIG. 10 is a side view for explaining the problem of the Fresnel lens of the present embodiment mounted on a vehicle.

FIG. 11 is a partial cross-sectional view showing an example of a Fresnel lens provided with a reflecting material or an absorbing material.

FIG. 12 is a front view for explaining the action when the Fresnel lens of FIG. 11 is attached to the windshield.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fresnel lens 2 Lens element part 3 Cab 4 Front glass 5 Mounting surface 6 Incident light 7 Reflected light 8 Incident light 9 Reflected light 10 Resin plate 11 Glass body 12 Line of sight 12n Line of sight 13 Crew 14 Line of sight 15 Target 16 Line of sight 17 Reflective material and / Or absorber 18 reflected light 19 orthogonal line

Claims (2)

[Scope of utility model registration request] 1. A large number of saw-toothed lens element parts formed by alternately connecting peaks and valleys on the opposite side of a flat mounting surface are formed in the longitudinal direction and mounted on a glass of a vehicle or the like. A transparent Fresnel lens that connects the peak point and the valley point when the inclination angle between the horizontal line of sight line connecting the viewpoint and the valley point is αn and the mounting angle of the mounting surface is θ An antireflection Fresnel lens characterized in that an angle of intersection βn between an inclined surface on the back side of the element portion and a line orthogonal to the mounting surface has a relationship of θ ≦ βn ≦ θ + αn. 2. A light ray reflecting material and / or an absorbing material is provided on an inclined surface on the back side of the lens element portion.
Antireflection Fresnel lens of.