A polarized lens can prevent transmission of reflected light. Therefore, it is used for, for example, protecting eyes by intercepting strong reflected light outdoors such as on a skiing area or in fishing, and for securing safety during driving a car by intercepting reflected light from a car traveling in the opposite direction.
For a plastic polarized lens, two kinds of polarized lens, that is, a polarized lens with a polarized film laid on the surface of the plastic lens material, and a sandwich structured polarized lens with a polarized film within the plastic lens material, have been proposed. The polarized lens with a polarized film laid on the surface of the plastic lens material (for example, Japanese Patent Laid-Open Application No. 09-258009 (Patent Document 1)) can make the thickness of the lens smaller, but has a serious disadvantage that the polarized film is liable to be peeled off from the lens material during a periphery polishing process (a process of polishing the edges of the lens to match a predetermined shape).
A resin used for a polarized film constituting a polarized lens has been hitherto essentially limited to polyvinyl alcohols. The polarized film is produced by uniaxial stretching of a polyvinyl alcohol film after adding iodine or a dichroic dye to make a film having molecular orientation in a uniaxial direction. A method of producing a polarized lens composed of a polarized polyvinyl alcohol film is disclosed, for example, in the pamphlet of WO 04/099859 (Patent Document 2).
However, a polarized lens prepared using a polarized polyvinyl alcohol film has a disadvantage of gradual invasion of moisture from the edge of the lens, or due to the environment from the peripheral portion of the lens toward the central portion and thus, deterioration develops over time.
In order to improve the above-described disadvantages, the pamphlet of WO 02/073291 (Patent Document 3) has proposed a polarized lens using a lens material including an impact-resistant polyurethane resin obtained from a diamine and an isocyanate prepolymer, and a polarized polyethylene terephthalate film.
However, this polarized lens has a disadvantage that the polarized film contained in the lens is clearly visible from outside, which gives an uncomfortable feeling to a person who wears the eyeglasses containing this lens. In addition, since a composition formed by mixing a diamine and an isocyanate prepolymer has a high viscosity as well as a short pot life, injection of the composition into a lens casting mold having a fixed polarized film therein is troublesome, and the production of a thin lens has been extremely difficult.
Therefore, in the plastic polarized lenses in the related art, there has been a demand for a plastic polarized lens, which has suppressed occurrence of the peeling-off of the polarized film during a downstream process of polishing the periphery of the lens, excellent water resistance, and suppressed uncomfortable feeling during wearing, and is capable of producing a thin product or the like.
On the other hand, it is desired to improve the contrast of an object to be viewed through the lens, in order to clarify the outlines and the colors of an object, and thus reduce visual fatigue regarding spectacle lenses. In order to improve the contrast, it is necessary to selectively shield (or cut) as far as possible a wavelength band which easily gives glare. For example, it is known that a neodymium compound can absorb visible light in the vicinity of 585 nm with high selectivity, and a spectacle lens including the neodymium compound improves the contrast. Improvement of the contrast of the object by a rare earth metal compound such as a neodymium compound is attributable to extremely sharp peak shapes of the absorption spectrum in the absorption wavelength band in the visible light region, that is, the absorption wavelength range is narrow and the wavelength selectivity is high. By such high wavelength selectivity, effects of a high transmission in a wavelength band requiring visibility and the wavelength band adversely affecting the glare being selectively absorbed can be obtained. Thus, by using a rare earth metal compound such as a neodymium compound, the contrast is improved, and thus, it is possible to obtain a spectacle lens having excellent visibility.
Furthermore, in addition to the rare earth metal compound such as typically a neodymium compound, it is also known that a specific organic coloring agent improves the contrast property of a spectacle lens. Examples of such organic coloring agents include a tetraazaporphyrin compound. The tetraazaporphyrin compound can provide excellent anti-glare performance and improvement of a contrast property for the spectacle lens, in a similar manner to the neodymium compound. That is, since a bright view field can be ensured with good light transmittance in the area excepting that of around 585 nm, derived from the sharpness of the peaks in the specific absorption wavelength, spectacle lenses having an extremely high balance of antiglare properties and visibility (contrast property) can be provided. In the case of using the organic coloring agent, a method in which an organic coloring agent is dissolved in a monomer composition in advance, followed by performing polymerization to obtain a lens is described in Examples of Japanese Patent Laid-Open Application No. 2008-134618 (Patent Document 4). Further, a plastic lens obtained by polymerizing a monomer composition having an organic coloring agent dissolved therein is disclosed in Examples of Patent Document 4, and a plastic lens obtained by laminating a base layer including the monomer composition on a polarized film is not specifically disclosed therein.
In Patent Document 4, an organic coloring compound that improves a contrast property is directly dissolved in a monomer composition and polymerized to form lens materials. Thus, according to the type of the monomers, particularly, there may be cases where the functions of the organic coloring compound are damaged due to the interaction with the monomers or the reactions during a polymerization reaction. Further, there are cases where for lenses for vision correction, there is a large difference in the thickness between the central portion and the peripheral portion, and in the case where the organic coloring compound is incorporated in the lens material itself, there have been cases where the color intensity in the central portion and the peripheral portion varies due to the coloration derived from the organic coloring compound. As it is used for vision correction of the intensity, the difference in the thickness between the central portion and the peripheral portion increases, and accordingly, such a tendency gets more remarkable. In this way, a polarized lens having a partially different thickness has changed in the color intensity in the portion, and accordingly, it has room for improvement in appearance. For example, in Examples of Patent Document 4, an organic coloring agent is directly dissolved in a monomer composition, and further, all of the lenses prepared in Examples are a Plano lens (a lens having a small difference in the thickness between the central portion and the peripheral portion). Accordingly, there is a desire for development of a lens having an improved contrast property, which can correspond to the lenses for vision correction.