Provided is a composition with which a film having excellent temporal stability and excellent adhesiveness with a support or the like can be formed. In addition, provided are a film, a near infrared cut filter, a solid image pickup element, an image display device, and an infrared sensor. The composition includes: a near infrared absorbing compound that includes a it-conjugated plane having a monocyclic or fused aromatic ring; and a compound A having a weight-average molecular weight of 3000 or higher that has a radically polymerizable ethylenically unsaturated group, in which the compound A includes a repeating unit having a graft chain.

The purpose of the present invention is to provide: a high-performance polarizing plate which functions for light in an infrared wavelength range; and a liquid-crystal display device or the like comprising the same.

Provided is a polarizing plate for an infrared range, which is a stretched film containing a dye exhibiting absorption in an infrared range, the film exhibiting dichroism.

A dibenzopyrromethene boron chelate compound is represented by the following formula (1):

##STR00001## in which X.sub.1 to X.sub.6 in the above formula (1) are each independently of one another a sulfur atom, a carbon atom having a hydrogen atom, or a carbon atom having a substituent R.sub.0, and the substituent R.sub.0 represents an alkyl group, an alkoxy group, an alkylthio group, an aromatic group, a halogen atom, a hydroxyl group, a mercapto group, a nitro group, a substituted amino group, an unsubstituted amino group, a cyano group, a sulfo group, an acyl group, a sulfamoyl group, an alkylsulfamoyl group, a carbamoyl group, or an alkylcarbamoyl group; and adjacent groups of X.sub.1 to X.sub.6 may be connected to each other to form a ring structure. The compound has an absorption band in a near-infrared light region, and a BO chelate structure due to a thiophene ring.

An object of the present invention is to provide an optical filter having excellent visible light-cut characteristics and near-infrared rays transmission properties at a specific wavelength that are compatible with one another even in the case where the incident angle is increased, according to reduction in height of equipment on which an optical sensor device is provided. The optical filter of the present invention includes a base material (i) including a resin layer containing a compound (Z) having an absorption maximum in the wavelength region of 700 to 930 nm, and a dielectric multilayer film formed on at least one surface of the base material (i), and has specific optical properties.

An object of the present invention is to provide a luminescent particle having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield; and a compound having an emission maximum wavelength in a long wavelength range of 680 nm or longer and exhibiting a high quantum yield in the particles. According to the present invention, provided is a luminescent particle containing at least one kind of compound represented by Formula (1) (definitions of substituents in the formula are as set forth in the description) and a particle.

##STR00001##

Provided are a color developing composition including a compound represented by Formula 1, a lithographic printing plate precursor having at least a layer including the color developing composition, a method for producing a lithographic printing plate in which the lithographic printing plate precursor is used, and a compound represented by Formula 1.

##STR00001##

A color developing composition which develops colors in a high density and does not significantly discolor when aged, a lithographic printing plate precursor which has excellent plate-inspecting properties by means of color development and is capable of maintaining strong color development even when aged after color development, a plate making method for a lithographic printing plate in which the lithographic printing plate precursor is used, and a new compound that can be preferably used as a color developer. The color developing composition of the present invention includes a compound represented by Formula 1. The compound in the present invention is represented by Formula 1. In Formula 1, R.sup.1 represents a group in which an R.sup.1O bond is cleaved by heat or exposure to infrared rays. ##STR00001##

A color developing composition which develops colors in a high density and does not significantly discolor when aged, a lithographic printing plate precursor which has excellent plate-inspecting properties by means of color development and is capable of maintaining strong color development even when aged after color development, a plate making method for a lithographic printing plate in which the lithographic printing plate precursor is used, and a new compound that can be preferably used as a color developer. The color developing composition of the present invention includes a compound represented by Formula 1. The compound in the present invention is represented by Formula 1. In Formula 1, R.sup.1 represents a group in which an R.sup.1O bond is cleaved by heat or exposure to infrared rays. ##STR00001##

The purpose of the present invention is to provide a photosensitive composition having excellent curability even when a colorant or other substance for attenuating or blocking radiated light is present at a high concentration, the film thickness thereof is large, and the light source is visible-to-infrared light, particularly infrared light having low energy. The present invention is a photosensitive composition characterized by containing as essential components (A) an onium salt represented by general formula (1), (B) a sensitizer, and (C) a radical polymerizable compound. (In formula (1), Rf each independently represents a C1-8 alkyl group, a C2-8 alkenyl group, or a C6-10 aryl group, 80% or more of hydrogen atoms bonded to the carbon atoms of each group being substituted with fluorine atoms, n represents an integer of 1 to 5, and A.sup.+ represents a monovalent onium cation.)

Provided are a film having excellent heat resistance and a film forming method. In addition, provided are an optical filter, a laminate, a solid image pickup element, an image display device, and an infrared sensor. The film includes an aggregate of a dye and a resin, in which an average particle size of the aggregate of the dye is 30 to 450 nm.