An optical system includes a display, a backlight configured to emit at least a light in a first wavelength range extending between about 400 nm and about 500 nm, and an optical film disposed adjacent the backlight and configured to absorb a light in a second wavelength range extending between about 415 nm to about 455 nm, wherein a ratio of the light in the second wavelength range transmitted by the optical film to the light in the first wavelength range transmitted by the optical film is less than or equal to 50%.

An optical system includes a display, a backlight configured to emit at least a light in a first wavelength range extending between about 400 nm and about 500 nm, and an optical film disposed adjacent the backlight and configured to absorb a light in a second wavelength range extending between about 415 nm to about 455 nm, wherein a ratio of the light in the second wavelength range transmitted by the optical film to the light in the first wavelength range transmitted by the optical film is less than or equal to 50%.

Provided is an additive for imparting ultraviolet absorbency, or an additive for imparting a high refractive index, which has satisfactory compatibility with a resin serving as a matrix and can maintain high transparency even if added in high concentrations. Also provided is an additive with which the function of imparting both ultraviolet absorbency and a high refractive index can be realized by means of one kind of additive. This additive is represented by the following Formula (I):

##STR00001## wherein at least one of R.sup.1a to R.sup.9a is a monovalent sulfur-containing group represented by the following Formula (i-1) or Formula (i-2):

##STR00002## wherein R.sup.10a to R.sup.12a each represent a divalent hydrocarbon group or the like; and R.sup.13a represents a monovalent hydrocarbon group or the like.

Provided is an additive for imparting ultraviolet absorbency, or an additive for imparting a high refractive index, which has satisfactory compatibility with a resin serving as a matrix and can maintain high transparency even if added in high concentrations. Also provided is an additive with which the function of imparting both ultraviolet absorbency and a high refractive index can be realized by means of one kind of additive. This additive is represented by the following Formula (I):

##STR00001## wherein at least one of R.sup.1a to R.sup.9a is a monovalent sulfur-containing group represented by the following Formula (i-1) or Formula (i-2):

##STR00002## wherein R.sup.10a to R.sup.12a each represent a divalent hydrocarbon group or the like; and R.sup.13a represents a monovalent hydrocarbon group or the like.

Ocular lenses having UV absorbing properties are disclosed. The ocular lens comprises a hydrogel polymer comprising polymerised residues derived from a polymerisable UV absorber of formula (I):

U-L-Py  (I)

wherein: U is a UV absorbing moiety; L is a hydrophilic non-polyalkylene glycol linker comprising an anionic, a zwitterionic or a saccharide moiety; and Py is an ethylenically unsaturated polymerisable moiety.

Ocular lenses having UV absorbing properties are disclosed. The ocular lens comprises a hydrogel polymer comprising polymerised residues derived from a polymerisable UV absorber of formula (I):

U-L-Py  (I)

wherein: U is a UV absorbing moiety; L is a hydrophilic non-polyalkylene glycol linker comprising an anionic, a zwitterionic or a saccharide moiety; and Py is an ethylenically unsaturated polymerisable moiety.

Provided is an additive for imparting ultraviolet absorbency, or an additive for imparting a high refractive index, which has satisfactory compatibility with a resin serving as a matrix and can maintain high transparency even if added in high concentrations. Also provided is an additive with which the function of imparting both ultraviolet absorbency and a high refractive index can be realized by means of one kind of additive. This additive is represented by the following Formula (I): ##STR00001## wherein at least one of R.sup.1a to R.sup.9a is a monovalent sulfur-containing group represented by the following Formula (i-1) or Formula (i-2):
R.sup.10a.sub.mSH  (i-1)
R.sup.11a.sub.nSR.sup.12a—S.sub.pR.sup.13a  (i-2) wherein R.sup.10a to R.sup.12a each represent a divalent hydrocarbon group or the like; and R.sup.13a represents a monovalent hydrocarbon group or the like.

Provided is an additive for imparting ultraviolet absorbency, or an additive for imparting a high refractive index, which has satisfactory compatibility with a resin serving as a matrix and can maintain high transparency even if added in high concentrations. Also provided is an additive with which the function of imparting both ultraviolet absorbency and a high refractive index can be realized by means of one kind of additive. This additive is represented by the following Formula (I): ##STR00001## wherein at least one of R.sup.1a to R.sup.9a is a monovalent sulfur-containing group represented by the following Formula (i-1) or Formula (i-2):
R.sup.10a.sub.mSH  (i-1)
R.sup.11a.sub.nSR.sup.12a—S.sub.pR.sup.13a  (i-2) wherein R.sup.10a to R.sup.12a each represent a divalent hydrocarbon group or the like; and R.sup.13a represents a monovalent hydrocarbon group or the like.

Provided is an ultraviolet absorber with a high molar extinction coefficient that is particularly superior in heat resistance, odor suppression at the time of thermal decomposition and long-wavelength absorption, as compared to a conventional ultraviolet absorber. The ultraviolet absorber is an ultraviolet absorber comprising a 2-phenylbenzotriazole derivative having a bonding group represented by the following formula (I) or (II):

##STR00001## wherein X represents a nitrogen atom, an oxygen atom or a residue obtained by eliminating a hydrogen atom from an amide group; l represents an integer of 0 or 1; Y.sup.1 represents a substituted or unsubstituted aromatic hydrocarbon group; m is 1 when X is a nitrogen atom or a residue obtained by eliminating a hydrogen atom from an amide group, or 0 when X is an oxygen atom; Y.sup.2 represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, or a substituted or unsubstituted aromatic hydrocarbon group,

##STR00002## wherein Y.sup.3 forms a substituted or unsubstituted hetero ring together with a nitrogen atom N.

Provided is an ultraviolet absorber with a high molar extinction coefficient that is particularly superior in heat resistance, odor suppression at the time of thermal decomposition and long-wavelength absorption, as compared to a conventional ultraviolet absorber. The ultraviolet absorber is an ultraviolet absorber comprising a 2-phenylbenzotriazole derivative having a bonding group represented by the following formula (I) or (II):

##STR00001## wherein X represents a nitrogen atom, an oxygen atom or a residue obtained by eliminating a hydrogen atom from an amide group; l represents an integer of 0 or 1; Y.sup.1 represents a substituted or unsubstituted aromatic hydrocarbon group; m is 1 when X is a nitrogen atom or a residue obtained by eliminating a hydrogen atom from an amide group, or 0 when X is an oxygen atom; Y.sup.2 represents a hydrogen atom, a substituted or unsubstituted aliphatic hydrocarbon group, or a substituted or unsubstituted aromatic hydrocarbon group,

##STR00002## wherein Y.sup.3 forms a substituted or unsubstituted hetero ring together with a nitrogen atom N.