Optical film

Details Optical film Optical film

2002-09-06

2004-11-16

Zacharia, Ramsey (Department: 1773)

Stock material or miscellaneous articles

Composite

Of polycarbonate

C428S480000, C428S523000, C524S089000, C524S186000, C524S358000

Reexamination Certificate

active

06818304

ABSTRACT:

The present invention relates to an optical film having both near infrared ray absorption property and color tone correcting property. Particularly, it relates to an optical film useful for an optical filter installed on the front (viewer's side) of a plasma display panel.
The principle of the plasma display panel (hereinafter referred to as PDP) is that a voltage is applied to a rare gas (such as helium, neon, argon or xenon) sealed between two sheets of plate glass, and ultraviolet rays generated at that time are applied to an emitter to generate visible light. From PDP, e.g. near infrared rays and electromagnetic waves radiate in addition to visible light. The near infrared rays may cause production of improper operating signals for near infrared ray remote-controls for home electric appliances such as home televisions, air conditioners and video players, or may have a bad influence over data transfer of e.g. POS (point-of-sale) system.
Accordingly, a method of using an optical film which shuts out near infrared rays having a wavelength of from 850 to 1,100 nm as an optical filter has been proposed as follows. For example, a plurality of metal oxide thin films or metal thin films are laminated on a transparent substrate by e.g. sputtering, and light in the near infrared region is reflected thereon and shut out, while the visible light is transmitted therethrough. However, in order to obtain a high degree of antireflection property, the lamination number has to be increased, thus increasing the number of steps, and the productivity tends to be significantly poor. Further, in a case where the film has to be formed in a large area, highly precise uniformity in the plane is required with the above optical thin film type material, whereby production tends to be difficult.
As functions further required, correction of the object color, balance correction of the display color and adjustment of the transmitted light may, for example, be mentioned. Accordingly, it has been proposed to separately provide an optical film comprising a transparent resin and a color tone correcting colorant which selectively absorbs visible light having a specific wavelength contained in the transparent resin (JP-A-2001-133624), however, the number of steps increases, and the productivity tends to be poor, such being unfavorable.
Accordingly, an optical film wherein a near infrared ray reflection colorant and a color tone correcting colorant are contained in a transparent resin in one layer has been proposed (JP-A-9-316115), however, it tends to be difficult to adjust optical properties since the transmittance is low. Further, since a coating having fine particles dispersed therein is used, coating conditions are limited, such being problematic in view of productivity.
Under these circumstances, the present invention has been made to overcome the above problems of prior art, and it is an object of the present invention to provide an optical film useful for e.g. an optical filter for a display device such as PDP, having high near infrared ray absorption property and color tone correcting property by itself, and excellent in practical durability and production stability.
The present invention provides an optical film having a layer made of a transparent resin containing an anthraquinone type colorant of the formula (1) or (2) and a diimmonium type colorant of the formula (3):
where, in the formulae (1) and (2), each of R
1
to R
15
which are independent of one another, represents a hydrogen atom, an alkyl group which may have a substituent (excluding a halogenated alkyl group), an alkoxy group, an aryloxy group, a halogen atom, an alkoxycarbonyl group, a halogenated alkyl group, an alkylthio group, an arylthio group, a cyano group, a nitro group, an amino group, an alkylamino group, an amide group, an acyloxy group, a hydroxyl group, a sulfo group or a carboxyl group. In the formula (2), R
16
represents a hydrogen atom or an alkyl group which may have a substituent. In the formula (3), each of R
17
to R
24
which are independent of one another, represent a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent, or an alkynyl group which may have a substituent, and X
−
is an anion.
Now, the present invention will be explained in detail with reference to the preferred embodiments.
The optical film of the present invention is an optical film having a layer made of a transparent resin containing an anthraquinone type colorant and a diimmonium type colorant.
The anthraquinone type colorant is represented by the above formula (1) or (2). In the formulae (1) and (2), each of R
1
to R
15
which are independent of one another, represents a hydrogen atom, an alkyl group which may have a substituent (excluding a halogenated alkyl group), an alkoxy group, an aryloxy group, a halogen atom, an alkoxycarbonyl group, a halogenated alkyl group, an alkylthio group, an arylthio group, a cyano group, a nitro group, an amino group, an alkylamino group, an amide group, an acyloxy group, a hydroxyl group, a sulfo group or a carboxyl group.
In the formula (2), R
16
represents a hydrogen atom or an alkyl group which may have a substituent.
In each of the above formulae (1) and (2), the alkyl group may, for example, be a methyl group, an ethyl group, a n-propyl group, an iso-propyl group, a n-butyl group, a sec-butyl group, an iso-butyl group, a tert-butyl group, a n-amyl group, a tert-amyl group, a n-hexyl group, a n-octyl group or a tert-octyl group. The alkyl group may have a substituent such as an alkoxycarbonyl group, a hydroxyl group, a sulfo group or a carboxyl group.
The alkoxy group may, for example, be a methoxy group or an ethoxy group, and the aryloxy group may, for example, be a phenoxy group or a p-chlorophenoxy group. Further, the alkoxycarbonyl group may, for example, be a methoxycarbonyl group or an ethoxycarbonyl group, the halogenated alkyl group may, for example, be a trifluoromethyl group or a pentafluoroethyl group, the alkylthio group may, for example, be a methylthio group, an ethylthio group, a propylthio group or a butylthio group, the arylthio group may, for example, be a phenylthio group or an o-carboxylphenylthio group, the alkylamino group may, for example, be a methylamino group or an ethylamino group, the amide group may, for example, be an acetoamide group or a propionamide group, and the acyloxy group may, for example, be an acetoxy group or a butyryloxy group.
The anthraquinone type colorant in the present invention is preferably one having a maximum absorption in the visible light region with a wavelength of from 400 to 700 nm.
The diimmonium type colorant is represented by the above formula (3).
In the formula (3), each of R
17
to R
24
which are independent of one another, represents a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group which may have a substituent, an aryl group which may have a substituent or an alkynyl group which may have a substituent.
The alkyl group may be the alkyl group as described above. The alkyl group may have a substituent such as an alkoxycarbonyl group, a hydroxyl group, a sulfo group or a carboxyl group.
The alkenyl group may, for example, be a vinyl group, a propenyl group, a butenyl group, a pentenyl group, a hexenyl group, a heptenyl group or an octenyl group. The alkenyl group may have a substituent such as a hydroxyl group or a carboxy group.
The aryl group may, for example, be a benzyl group, a p-chloropentyl group, a p-methylbenzyl group, a 2-phenylmethyl group, a 2-phenylpropyl group, a 3-phenylpropyl group, an &agr;-naphthylmethyl group or a &bgr;-naphthylethyl group. The aryl group may have a substituent such as a hydroxyl group or a carboxy group.
The alkynyl group may, for example, be a propynyl group, a butynyl group, a 2-chlorobutynyl group, a pentynyl group or a hexynyl group. The alkynyl group may have a substituent such as a hydroxyl group or a carboxy group.
X
−
represents an anion such as a chlorine

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