JP4847989B2 - Light control and polarization lens for sunglasses - Google Patents

Description

  The present invention relates to a dimming / polarizing lens for sunglasses having a dimming function and a polarizing function.

  Sunlight is a mixed wave of longitudinal and transverse waves, but when light passes through a polarizing lens having optical anisotropy, the oscillatory wave of either the longitudinal wave or the transverse wave is selected and allowed to pass through. It can block the passage of waves. Therefore, the water surface, road surface, roof tiles, etc. do not appear to be glaring due to the reflection of sunlight, and it is an optimal lens that is not dazzling in the summertime when sunlight is strong. Of course, sunglasses may be used as long as they simply block the sun rays, but the sunglasses do not have this function of blocking the vibration wave of one side of the sun rays, and it is possible to completely prevent glare of reflected light. I can't.

In addition, there are known dimming / polarizing lenses having both a polarizing function for blocking reflected light and a dimming function for adjusting brightness and darkness. In recent years, there has been a demand for lenses having such a dimming / polarizing function. It is growing. A dimming lens is a lens that has the function of adjusting the amount of light by changing the concentration according to the amount of ambient UV light. The lens material is mixed with silver halide, and the reversibility of halogen and silver by UV light. Can be colored or faded by bonding.
Here, in order to manufacture a laminated lens having a light control / polarization function, it is known that an adhesive is applied to the surface of a lens base, a polarizing film and a light control lens are stacked, and both are bonded. .

The “laminated lens manufacturing method and mold thereof” according to Japanese Patent Application Laid-Open No. 2007-164030 is a lens manufacturing method for manufacturing a high-quality lens having optimal polarization degree and dimming degree easily and at low cost.
That is, a lower mold, a seal member, and a lens base are prepared, and the lower mold is inserted into the seal member for positioning, and a lens material for forming a light control lens or a polarizing lens is flowed on the mold surface of the lower mold In the state where the lens base is opposed to the lower mold, the lens base is fitted into the seal member, and the lens material is spread while being pressed by the lens base, and the cavity between the lower mold and the lens base is filled with the lens material. The lens material is cured to form a polarizing lens or a light control lens on one surface of the lens substrate.

  On the other hand, a dimming / polarizing lens having a structure in which a polarizing film is sandwiched between two lenses is known instead of the injection molding as described above. Thus, in the light control / polarization lens constructed by pasting using existing lenses, a mold for injection molding is unnecessary, and an injection molding apparatus is not required. In addition, the performance of the dimming / polarizing lens manufactured using the existing high-precision dimming lens and white lens is improved.

  FIG. 4 is a cross-sectional view showing a conventional dimming / polarizing lens combination structure. In the figure, (a) represents a light control lens, (b) represents an ordinary white lens, and (c) represents a polarizing film. The light control / polarization lens has a structure in which a polarization film (c) is sandwiched between the light control lens (a) and the white lens (b), and is formed by bonding them together.

By the way, as is clear from the figure, the thickness of the light control lens (a) on the front side is not constant, and is thick (T ₁ ) on the central side (inside) and thin (T ₂ ) on the outside. . Therefore, the dimming function at the inner part (center side of the front part) with a large thickness is high, but the dimming function at the outer part is low. That is, the inner portion is dark and the outer portion is light. A light control / polarization lens combining such a light control lens (A) is not preferable.

  2. Description of the Related Art In recent years, lenses for sunglasses that have a shape that extends outward so as to be familiar with the face have been adopted. The aim is to ensure a wide field of view, to prevent the wind from getting involved, or to place importance on fashion. When such lenses are configured with the same thickness, what is called a prism phenomenon occurs. In other words, the scenery may appear distorted, which is mainly due to the inclination of the lens itself, which is caused by extending it outward to adapt to the face.

That is, when the thickness of the lens is constant, the thickness of the lens through which the light passes when viewed in an oblique direction is larger than the thickness of the lens through which the light passes when looking straight straight. In order to correct this lens thickness, a decenter lens with a shifted optical center is used. As shown in FIG. 4, the light control lens (A) is a decenter lens, and the outer thickness (T ₂ ) is thinner than the thickness (T ₁ ) on the center side. The lens thickness in the direction in which the lens passes is equal.

By using a decentered lens with an optical center misalignment as the dimming lens (a), the prism phenomenon is eliminated, but the function as the dimming lens varies, and the inner portion (front portion) with a large thickness There is a problem that the color is dark on the center side) and light on the outside.
“Manufacturing method of laminated lens and molding die thereof” according to Japanese Patent Application Laid-Open No. 2007-164030

  As described above, the dimming / polarizing lens having the structure in which the dimming lens, the white lens, and the polarizing film are laminated and the polarizing film is sandwiched between the dimming lens and the white lens has the above-described problems. The problem to be solved by the present invention is this problem, and provides a dimming / polarizing lens for sunglasses in which there is no change in color density between the inner part (center side of the front part) and the outer part.

  The light control / polarization lens according to the present invention has a structure in which a light control lens positioned on the front side, a white lens positioned on the back side, and a polarizing film are laminated, and the polarization film is sandwiched between the light control lens and the white lens. . Therefore, the basic structure is common to the conventional dimming / polarizing lens. However, in the present invention, the thickness of the front side light control lens is constant, the color intensity is the same at any position, and the light control function is made uniform.

  On the other hand, the thickness of the white lens is changed to be thick on the inside and thin on the outside. That is, in the present invention, the white lens located on the back side is a decenter lens, and the optical center is shifted. Here, the manufacturing method of the above-mentioned white ball lens which is a decenter lens is not limited.

In the light control / polarization lens of the present invention, since the light control lens located on the front side has a uniform thickness, it has the same color density at any position, and the light control function is uniform. On the other hand, the white lens is a decentered lens having a thicker inner side (center side of the front portion) and a thinner outer side.
Therefore, if the dimming / polarizing lens of the present invention is used as a lens for sunglasses that curves along the face and extends outward, the sunglass that combines the dimming function and the polarizing function and does not cause distortion due to the prism phenomenon, Become.

  FIG. 1 is a development view showing a light control / polarization lens according to the present invention, in which 1 denotes a light control lens, 2 denotes a white lens, and 3 denotes a polarization film. The dimming lens 1 and the white lens 2 are laminated and bonded with the polarizing film 3 interposed therebetween to form the dimming / polarizing lens shown in FIG.

  Here, the polarizing film 3 can be formed by directly bonding a polarizing element to a fusible material. Sunlight can be regulated by constituting the polarizing film 3 in between. A conventional polarizing lens is formed by sandwiching this polarizing film between a white lens on the front side and a white lens on the back side, and laminating and adhering.

  By the way, the dimming / polarizing lens of the present invention does not sandwich the polarizing film 3 between both white lens lenses, but uses one side (front side) as a dimming lens. The light control lens 1 is a lens having a function of adjusting the amount of light by changing the density depending on the amount of ambient ultraviolet rays. The lens material is mixed with silver halide, and the reversal of halogen and silver by ultraviolet rays is performed. It can be colored and faded with a mechanical bond. In the present invention, the thickness of the light control lens 1 is constant. That is, the lens is curved with a predetermined thickness and a predetermined curvature, and therefore the color density is constant at any position.

  For this reason, the light transmittance is equal, and when wearing sunglasses, the central side is dark and the outside does not feel bright. Thus, although the thickness of the light control lens 1 is constant, in the present invention, the thickness of the white lens 2 is different. When assembled as sunglasses, it is thick on the inside (center side of the front part) and thin on the outside, forming a decenter lens. Since the white lens 2 is a colorless and transparent plastic or glass lens, it does not cause light and dark due to a change in thickness.

  By the way, the white lens 2 is polished in the case of a glass lens and molded in the case of a plastic lens. However, since the polarizing film 3 is laminated with the light control lens 1, the curvature on the front side is adjusted as described above. The back side curvature of the optical lens 1 is the same, and the back side curvature of the white lens 2 is further increased. That is, as shown in FIG. 3, the white lens 2 is cut out from a circular uncut lens 4 having a predetermined outer diameter, but when the white lens 2 is manufactured, the position of the line of sight is undefined. It cuts out so that it may become the optical center M of the cut lens 4. FIG.

  The circular uncut lens 4 has a geometric center O and is separated from the optical center M by a predetermined distance. That is, it constitutes a decenter lens, and the optical center is configured such that the line of sight coincides when wearing sunglasses. That is, the optical center MM of both white lens 2, 2 is the distance between the pupils.

  By the way, the manufacturing method of the white ball lens 2 constituting the decenter lens is approximately the same size as the uncut lens 4 as shown in FIG. 3, and the decenter lens is manufactured by polishing the surface of the uncut lens 4. Is also possible. And it cuts or grinds on the outer periphery which fits a rim shape in the state which became the decenter lens.

FIG. 3 is a development view of a light control / polarization lens according to the present invention. The cross-sectional view of the light control and polarization lens according to the present invention. Cutting form of white lens from target lens. Sectional structure of a conventional polarizing lens.

Explanation of symbols

1 Photochromic lens 2 Shiratama lens 3 Polarized film 4 Uncut lens

Claims (1)

In a dimming / polarizing lens for sunglasses in which a polarizing film is sandwiched and laminated between a front side dimming lens and a back side white lens, the dimming lens is formed with a curved surface whose thickness is constant, A dimming / polarizing lens for sunglasses, wherein the white lens uses a decenter lens in which the thickness at the center of the front portion of the sunglasses is increased and the thickness at the outside of the front portion is decreased to shift the optical center.

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