KR20210143754A - Authentication device and film - Google Patents

Abstract

An object of the present invention is to provide an authentication device that does not depend on the orientation angle of a film for authentication, and is an authentication device having a light source, a polarizer, a film and a light sensitivity sensor, wherein a film having specific characteristics is disposed between the polarizer and an object to be authenticated An authentication device that has been used is intended for this purpose.

Description

Authentication device and film

The present invention relates to an authentication device having a light source, a polarizer, a film and a light sensitivity sensor.

With the development of image processing technology and data analysis technology in recent years, various authentication systems have been put into practical use. In particular, biometric authentication devices, such as fingerprint authentication, iris authentication, vein authentication, and face authentication, have begun to be used in various electronic products such as mobile phones and vehicles, with improved precision and reduced cost. Since it is expected to be used in vehicles, electronic payments, etc. in the future, there is a demand for an authentication device having further precision, lower cost, and durability in the case of long-term use.

As disclosed in Patent Document 1, in general, an optical authentication device irradiates light emitted from a light source to an object to be authenticated, receives and captures the reflected light by a photosensitive sensor, and registers a patterned image in advance. Authentication is performed by matching the existing pattern. In such an authentication device, when light other than that emitted from a light source becomes incident, since it becomes a cause of erroneous authentication, a polarizer is used to suppress the reflection of external light in many cases. In addition, by using a film of a thermoplastic resin such as polyester or polycarbonate for the outermost layer, deterioration of the authentication function due to damage or scratches is prevented.

International Publication No. 2017/126153

However, when the film has polarization or optical rotation, the light from the light source is polarized / rotated, and as a result, the polarized / rotated light is blocked by the polarizer until it reaches the photosensitivity sensor, so the authenticity is lowered. A problem arises that

Two countermeasures can be considered for this problem. First, there is a method in which an unstretched or finely stretched film such as polycarbonate, which is almost optically isotropic, is used as a protective film. However, a film with a low draw ratio is easily torn and has difficulty in impact resistance. Moreover, a polycarbonate film with high impact resistance has the subject that it is expensive.

The second is a method in which the oriented polyester film is used as a protective film and the main orientation axis of the oriented polyester film is parallel to the transmission axis of the polarizer, whereby polarization in the protective film is substantially eliminated. However, in such a method, when the direction of the main alignment axis and the transmission axis of the polarizer shift only a few times, the polarization property becomes visible and there is a problem that the authenticity decreases.

In addition, in authentication devices using OLED (Organic Light Emitting Diode) as a light source, deterioration of OLED due to ultraviolet rays or the like becomes a stumbling block for long-term use. is a task.

An object of the present invention is to solve the above problems, and an object of the present invention is to provide an authentication device that does not depend on the orientation angle of the film.

The present invention is intended to solve the above problems. That is, it is an authentication device having a light source, a polarizer, a film, and a photosensitive sensor, wherein the above-described film is disposed between the polarizer and the object to be authenticated, and the following (1) and (2) are satisfied.

(1) The transmittance|permeability of the light source emitted from the said light source is 70% or more and 100% or less in the wavelength of the strongest intensity|strength of the said light source.

(2) An integer n satisfying the following formula (I) exists.

(I) A×n-150≤Re≤A×n+150

Here, A is the wavelength (nm) showing the strongest intensity in the light emitted from the light source, and Re is the in-plane when the film is measured at a wavelength of 587.8 nm at an incident angle of 0° using the parallel Nicole rotation method. is the phase difference (nm).

ADVANTAGE OF THE INVENTION According to this invention, the authentication device which does not depend on the orientation angle of a film can be provided. In addition, an inexpensive film can be used, and durability of the light source and impact resistance of the screen can be improved.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically an example of the structure of the authentication device of this invention.
Fig. 2 is a diagram showing an example of movement of light used for authentication in the authentication device of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, although embodiment of this invention is described in detail, this invention is limited to embodiment including the following example, and is not interpreted, The objective of invention can be achieved, and it does not deviate from the summary of invention. Various changes in scope may be expected.

The authentication device of the present invention is an authentication device having a light source, a polarizer, a film, and a light sensitivity sensor, and is an authentication device in which a film satisfying the following (1) and (2) is disposed between the polarizer and the object to be authenticated.

(1) The transmittance|permeability in the wavelength in which the said film has the strongest intensity|strength of the light radiate|emitted from the said light source is 70 % or more and 100 % or less.

(2) The wavelength having the strongest intensity of the light emitted from the light source is A (nm), and the in-plane retardation at a wavelength of 587.8 nm at an incident angle of 0° measured by the parallel Nicole rotation method of the film is Re (nm). When it does, it satisfies the following (I') formula.

(I') A×n-150≤Re<A×n+150

However, n is an integer.

More specifically, the authentication device of the present invention is an authentication device having a light source, a polarizer, a film and a light sensitivity sensor, wherein the above film is disposed between the polarizer and the object to be authenticated, and also satisfies the following (1) and (2) It is an authentication device, characterized in that.

(1) The transmittance|permeability of the light source emitted from the said light source is 70% or more and 100% or less in the wavelength of the strongest intensity|strength of the said light source.

(2) An integer n satisfying the following formula (I) exists.

(I) A×n-150≤Re≤A×n+150

Here, A is the wavelength (nm) showing the strongest intensity in the light emitted from the light source, and Re is the in-plane when the film is measured at a wavelength of 587.8 nm at an incident angle of 0° using the parallel Nicole rotation method. is the phase difference (nm).

The authentication device of this invention consists of the light source 1, the polarizer 2, the film 3, and the photosensitive sensor 4, as shown in FIG. It is preferable to arrange|position in order of a light source, a polarizer, and a film. Hereinafter, these structures are described.

<Light Source>

As the kind of light source constituting the authentication device of the present invention, any light source can be used as long as it emits light in a wavelength region detectable by a photosensitive sensor. For example, any light source, such as a fluorescent light source, such as a hot cathode tube, a cold cathode tube, inorganic EL, an organic electroluminescent element light source (organic EL), a light emitting diode (LED), an incandescent light source, can be used. In particular, organic EL or LED is a suitable light source. As will be described later, the in-plane retardation of the film is adjusted to approximately an integer multiple of the wavelength having the strongest intensity of the light emitted from the light source (the wavelength having the strongest intensity of the light emitted from the light source is sometimes referred to as the light source wavelength). It becomes important to improve authentication. Since it leads to a decrease in authenticity as the amount of light with a wavelength spaced apart from the approximate divisor of the in-plane retardation of the film increases, it is preferable to use a light source having a narrow emission wavelength band and adjustable emission wavelength. It is preferable that the half-width of the peak having the strongest intensity of the light emitted from the light source is 5 nm or more and 150 nm or less. It is more preferable that they are 5 nm or more and 70 nm or less. It is especially preferable that they are 5 nm or more and 50 nm or less. The narrower the wavelength band and the closer to an integer multiple of the in-plane retardation of the film, the more it is possible to suppress the dependence of the orientation angle of the film affecting the authenticity. The orientation angle here refers to the angle which the transmission axis of a polarizer and the main orientation axis of a film make. In addition, in this invention, the main orientation axis of a film shows the direction of the slow axis calculated|required by the measuring method mentioned later. Moreover, when installing this authentication device on the surface of curved displays etc., flexible organic electroluminescent can be used preferably.

When using organic EL as a light source, it is especially preferable to set it as the structure which shields the ultraviolet-ray mentioned later. By shielding an ultraviolet-ray, the fault of organic EL that ultraviolet-ray deterioration is easy can be supplemented, introduce|transducing the outstanding point of organic EL, such as flexibility.

The light source may have one type of emission peak or may have two or more types of emission peaks, but it is preferable to have one type of emission peak in order to improve color purity. Moreover, it is also preferable from points, such as a security improvement, to use combining arbitrarily the some light source from which the kind of emission peak differs. When using a plurality of light sources, it is preferable to use a film suitable for each light source (in-plane retardation is approximately an integer multiple of the wavelength of the light source).

<Light sensitivity sensor>

The authentication device of the present invention needs to be configured to include a light sensitivity sensor in order to recognize the light reflected from the object. Examples of the photosensitive sensor include a charge-coupled device (CCD), a complementary metal-oxide-semiconductor (CMOS), and the like. Among them, it is preferable to use CMOS (including live MOS, back-illuminated CMOS, stacked CMOS, curved CMOS, organic thin-film CMOS, Foveon, etc.) from the viewpoints of manufacturing cost and read speed. In particular, by combining the organic thin-film CMOS with the ultraviolet shielding described later, it is possible to compensate for the difficulties of the organic thin-film CMOS, which are prone to deterioration by ultraviolet rays, while obtaining an organic thin-film CMOS such as a thin film.

<Polarizer>

In the authentication device of this invention, in order to prevent erroneous authentication by incident of external light, it is necessary to set it as the structure containing a polarizer. External light here refers to light incident to the photosensitive sensor side from the film other than the light emitted from the light source. Although it can select arbitrarily as a raw material of a polarizer, For example, it can form by dyeing|staining a polyvinyl alcohol (PVA) film with dichroic materials, such as an iodine compound, and performing an extending|stretching process. As an example of the PVA film, Kurarese VF-PS#7500 or the like can be applied.

<Film>

The authentication device of this invention needs to be set as the structure containing a film. The film needs to have a transmittance (light source light transmittance) of 70% or more and 100% or less at a wavelength having the strongest intensity of light emitted from the light source. When the transmittance|permeability is less than 70 %, light may not fully reach a photosensitive sensor, but authentication property may fall. More preferably, they are 80 % or more and 100 % or less.

Further, in the authentication device of the present invention, the wavelength (light source wavelength) showing the strongest intensity in the light emitted from the light source is A (nm), and the wavelength at an incident angle of 0° measured by the parallel Nicol rotation method of the film is 587.8 nm. When the in-plane retardation of Re(nm) is assumed, it is necessary to satisfy the equation (I').

(I') A×n-150≤Re<A×n+150

However, n is an integer.

More specifically, the authentication device of the present invention is an authentication device having a light source, a polarizer, a film, and a light sensitivity sensor, wherein the film is disposed between the polarizer and an object to be authenticated, and also satisfies the following (1) and (2) It is an authentication device, characterized in that.

(1) The transmittance|permeability of the light source emitted from the said light source is 70% or more and 100% or less in the wavelength of the strongest intensity|strength of the said light source.

(2) An integer n satisfying the following formula (I) exists.

(I) A×n-150≤Re≤A×n+150

Here, A is the wavelength (nm) showing the strongest intensity in the light emitted from the light source, and Re is the in-plane when the film is measured at a wavelength of 587.8 nm at an incident angle of 0° using the parallel Nicole rotation method. is the phase difference (nm).

Equation (I) shows that the in-plane retardation of the film is approximately an integer multiple of the wavelength of the light source (range from an integer multiple of ±150 nm). The in-plane retardation of the film is preferably in the range of ±120 nm from an integer multiple of the wavelength of the light source, and more preferably in the range of ±100 nm. When the in-plane retardation of the film is not within the above range, since the light emitted from the light source is polarized when it passes through the film, the effect of light absorption by the polarizer becomes large, and a decrease in authenticity becomes a problem. Also, the degree of polarization depends on the orientation angle. Further, from the viewpoint of extending the process window, the in-plane retardation is preferably 400 nm or more, more preferably 600 nm or more, and still more preferably 800 nm or more. In addition, as will be described later, one of the means of adjusting the in-plane retardation is to adjust the draw ratio, but from the viewpoint of improving the film strength, it is not preferable to strongly stretch in only one direction, so it is preferable that the in-plane retardation is less than 3000 nm do. Since the in-plane retardation is greatly affected by the film thickness, it is difficult to produce a film with an in-plane retardation of less than 3000 nm when the film thickness is too thick, and similarly, if the film thickness is too thin, a film with an in-plane retardation of 400 nm or more it is difficult In order to make in-plane retardation into the said preferable range, it is preferable from a viewpoint of easiness of in-plane retardation control to set it as 10 micrometers or more and less than 100 micrometers in thickness. It is more preferable that they are 15 micrometers or more and less than 50 micrometers.

Moreover, although it is also possible to improve authentication property by making an in-plane retardation approach 0 by lowering|hanging a draw ratio, since a film becomes brittle, it is unpreferable from a viewpoint of impact resistance.

In addition, although it is most preferable to measure the in-plane retardation at the wavelength of the light source, it is measured at 587.8 nm from the light intensity stability of a measuring apparatus. It is preferable that the difference between the in-plane retardation at the wavelength of the light source and the in-plane retardation at the wavelength measurable by the measuring device is 40 nm or less.

A mechanism in which light absorption by the polarizer is increased when the in-plane retardation is not within the above range will be described. When the authentication object is authenticated in the authentication device of the present invention, the light emitted from the light source passes through the polarizer and the film in the order, then reaches the authentication object, and the light reflected from the authentication object passes through the film and the polarizer in the order and is detected by a photosensitive sensor. When the path of light is indicated by an arrow, it becomes the same as that of FIG.

A polarizer absorbs light in a specific polarization state and transmits only light in other polarization states. Therefore, when light emitted from the light source passes through the polarizer, it becomes linearly polarized light or circularly polarized light. In the case where the film has no polarization (optically isotropic), the polarization state does not change before and after the film passes through the light emitted from the light source, passing through the polarizer and incident on the film, and the light reflected from the object to be authenticated and incident on the film. does not Therefore, in the case where the film has no polarization (optically isotropic), the polarization state is emitted from the light source and passes through the polarizer and then passes through the film, and after reflection from the object to be authenticated, passes through the film and enters the polarizer is unchanged, so it passes without being absorbed by the polarizer and is recognized by the light sensitivity sensor.

However, when the film has polarization, the polarization state is changed when light emitted from the light source and passed through the polarizer passes through the film and passes through the film after being reflected by the object to be authenticated. Therefore, some light is absorbed by the polarizer and cannot pass. Therefore, the intensity|strength of the light which reaches|attains to a photosensitive sensor falls, and it leads to the fall of authentication property. The polarization of the film is caused by the difference in the optical path length between the direction of the main alignment axis and the direction perpendicular to the main alignment axis, that is, the in-plane retardation. When the light vibrating in the main alignment axis direction is faster or slower than the light vibrating in the vertical direction, the phases of the two lights are shifted and polarized.

On the other hand, in the authentication device of the present invention, by setting the in-plane phase difference to an approximately integer multiple of the wavelength of the light source, the phase shift is made an approximately integer multiple of 2π, and the phase shift is substantially close to zero. When the shift of the phase becomes small, even if the orientation angle shifts, the decrease in the intensity of the light after transmission of the polarizer is suppressed. Therefore, when the in-plane retardation of the film is within the range of the formula (I), the decrease in authenticity can be suppressed.

For example, when the wavelength of the light source is 525 nm, when the in-plane retardation is an integer multiple of 525 nm, it has been found that the transmittance is high regardless of the orientation angle. Authenticity was also confirmed by the method described later, and when the authentication property was A or B by adjusting the in-plane phase difference, it was confirmed that good authentication performance was exhibited for the screen protection use of the in-screen fingerprint authentication smartphone. As a model of a smartphone, Vivo X20 Plus UD, X21, and NEX are mentioned, for example.

In addition, when the light source exists in multiple colors, and any color is to be received by the photosensitive sensor, the film having an in-plane retardation that is an integer multiple of the wavelength having the second strongest intensity of the light emitted from the light source is used. it is preferable

In other words, the wavelength showing the second strongest intensity in the light emitted from the light source is B (nm), and the in-plane retardation when the film is measured at a wavelength of 587.8 nm at an incident angle of 0° using the parallel Nicol rotation method. When Re (nm), it is preferable that an integer m satisfying the following formula (II) exists.

(II) B×m-150≤Re≤B×m+150.

In addition, the "wavelength showing the second strongest intensity" referred to herein is selected from wavelengths that become peaks when the wavelength dependence of the intensity of the light from each light source is plotted. A "peak" here refers to a wavelength that becomes a local maximum when the wavelength dependence of the emission intensity of light is plotted. The "local maximum" as used herein refers to a wavelength at which the sign changes from positive to negative when the intensity of light is differentiated by the wavelength. When there is only one light source, among the wavelengths used as the peak, the wavelength that is the second strongest after "wavelength (A) showing the strongest intensity" Wavelength (B)". However, let the intensity of A be P(A), and let the intensity of B be P(B).

1. A-20<B<A+20

2. P(B)×100<P(A)

The first point is excluded from being regarded as the peak of B when the tip of the peak of A is split or the peak of A has a shoulder. Therefore, depending on the peak shape, it is considered that it is necessary to extend the exclusion range without staying within the range of +/-20 nm of A.

The second point above excludes that noise is regarded as the peak of B. Therefore, depending on the noise level at the time of measuring the wavelength dependence of the intensity of light of each light source, even an intensity of 1/100 or more of A may be regarded as noise.

When there are two light sources, among the "wavelengths with the strongest intensity" in each light source, the one with the strongest intensity is designated as the "wavelength showing the strongest intensity (A)", and the one with the weakest intensity is designated as the "second strongest intensity". The indicated wavelength (B)”.

Similarly, even when there are three or more light sources, it is preferable to make the in-plane retardation of a film into a common multiple of "the wavelength with the strongest intensity|strength" of each light source.

In addition, even if it is not the "wavelength having the strongest intensity" in each light source, it is preferable to use a film having an in-plane retardation that is an integer multiple of a wavelength having an important role in the structure of the authentication device. The important role here is not limited to imaging for authentication, but also includes a role that affects an object to cause a change, exclusion of influences other than the object, and the like.

Although the method for making the in-plane retardation of a film into the said range is not limited, It is achieved by adjusting the refractive index of resin, a draw ratio, and adjusting a extending|stretching temperature.

As the resin constituting the film of the present invention, for example, polyester such as polyethylene terephthalate (abbreviation: PET) and polyethylene naphthalate (abbreviation: PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate ( Abbreviation: TAC), cellulose acetate butyrate, cellulose acetate propionate (abbreviation: CAP), cellulose acetate phthalate and cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, Diotactic polystyrene, polycarbonate (abbreviation: PC), norbornene resin, polymethylpentene, polyether ketone, polyimide, polyether sulfone (abbreviation: PES), polyphenylene sulfide, polysulfones, polyether E Mid, polyether ketoneimide, polyamide, fluororesin, nylon, polymethyl methacrylate, acryl and polyarylates, Atone (registered trademark) (trade name, manufactured by JSR Corporation) and Arpel (registered trademark) (trade name, Mitsui Corporation) Cycloolefin-based resins, such as Gwasa Co., Ltd.), etc. are mentioned.

Among these resins, a film made of at least polyester as a constituent material is preferably used from the viewpoint of physical properties such as cost, ease of availability, expansion of the process window at the time of film forming, strength, and elongation at break.

The polyester as described in the present invention is a condensation polymer obtained by polymerization from a monomer containing an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol as main constituent components. As a method for industrially producing polyester, a known transesterification reaction (ester exchange method) or a direct esterification reaction (direct polymerization method) is used. Here, as aromatic dicarboxylic acid, for example, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4, 4'-diphenyl dicarboxylic acid, 4,4'- diphenyl ether dicarboxylic acid, 4,4'- diphenyl sulfone dicarboxylic acid, etc. are mentioned. Examples of the aliphatic dicarboxylic acid include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, 1,4-cyclohexanedicarboxylic acid and their ester derivatives. Among them, terephthalic acid and 2,6-naphthalenedicarboxylic acid, which exhibit a high refractive index, are preferably used. A dicarboxylic acid component may use 1 type among these, and may use it in combination of 2 or more types.

Moreover, as a diol component, for example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1 ,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2- Bis(4-hydroxyethoxyphenyl)propane, isosorbate, spiroglycol, etc. are mentioned. Among them, ethylene glycol is preferably used. These diol components may be used alone or in combination of two or more.

It is preferable that it is a laminated|multilayer film which laminated|stacked the layer containing resin A, and the layer containing resin C different from resin A from a viewpoint of the improvement of film strength and stretchability|strengthening 5 or more layers laminated|stacked alternately. In addition, when the resin A contains the crystalline resin A as the main component and the resin C contains the amorphous resin C as the main component, it is preferable from the viewpoint of facilitating adjustment of the in-plane retardation. As the low-refractive-index resin, an amorphous resin or the like whose refractive index is difficult to increase during stretching can be used.

Examples of the crystalline resin include polyethylene terephthalate and its copolymers, polyethylene naphthalate and its copolymers, polybutylene terephthalate and its copolymers, polybutylene naphthalate and its copolymers, further polyhexamethylene terephthalate and Its copolymer, polyhexamethylene naphthalate, its copolymer, etc. can also be used. At this time, as a copolymerization component, it is preferable that 1 or more types of said dicarboxylic acid component and diol component are respectively copolymerized.

The low refractive index resin is not particularly limited, and chain polyolefins such as polyethylene, polypropylene, poly(4-methylpentene-1) and polyacetal, ring-opening metathesis polymerization of norbornenes, addition polymerization, and other olefins Biodegradable polymers such as alicyclic polyolefin, polylactic acid, and polybutyl succinate, polyamides such as nylon 6, nylon 11, nylon 12, and nylon 66, aramid, polymethyl methacrylate, polyvinyl chloride, poly vinylidene chloride, polyvinyl alcohol, polyvinyl butyral, ethylene vinyl acetate copolymer, polyacetal, polyglucolic acid, polystyrene, styrene copolymer polymethyl methacrylate, polycarbonate, polypropylene terephthalate, polyethylene terephthalate, Polyester such as polybutylene terephthalate and polyethylene-2,6-naphthalate, polyethersulfone, polyetheretherketone, modified polyphenyleneether, polyphenylenesulfide, polyetherimide, polyimide, polyarylate, Ethylene tetrafluoride resin, ethylene trifluoride resin, ethylene trifluorochloride resin, tetrafluoroethylene-6 fluoride propylene copolymer, polyvinylidene fluoride, etc. can be used. Among them, from the viewpoint of strength, heat resistance, transparency, and versatility, in particular, also from the viewpoint of adhesion and lamination properties with the crystalline resin, it is most preferable as the resin C to contain polyester as a constituent component. Here, the low refractive index resin may be a copolymer or a mixture may be sufficient as it.

For example, since polyester containing isophthalic acid can reduce crystallinity, in-plane retardation can be easily suppressed, and even if it is biaxially stretched, the refractive index in the thickness direction is difficult to decrease, so Even if the incident angle of the light is changed, the occurrence of rainbow spots can be suppressed. Moreover, as another preferable amorphous polyester, the polyester containing spiroglycol as a copolymerization component is preferable. Since the polyester containing spiroglycol is difficult to orientate in the film deformation by biaxial stretching or bowing, it is difficult to generate|occur|produce the in-plane retardation fluctuation|variation in the width direction. Moreover, since there exists an effect that a glass transition point becomes high, the increase in thermal contraction rate by using an amorphous resin can be suppressed. In addition, preferred copolymerized amorphous components include cyclohexanedimethanol, neopentylglycol, cyclohexanedicarboxylic acid, isosorbide, and the like.

In addition, although the said film may be an unstretched film or a stretched film may be sufficient, the film stretched in at least one direction from a viewpoint of intensity|strength, in-plane retardation control, and productivity is preferable. In particular, when the film of the authentication device is supported by a material that may be broken, such as glass, it is preferable that the elongation at break is improved by appropriately stretching and the scattering of fragments due to damage to the surface can be prevented. By increasing the draw ratio in either the longitudinal direction or the width direction, the molecules in the film are oriented and the in-plane retardation can be improved. By enlarging the draw ratio in the width direction, the in-plane retardation and the main orientation axis become uniform in the width direction, and the usable product width can be large, which is preferable. When heat treatment is performed after stretching to reduce thermal shrinkage, further stretching in the width direction during heat treatment, cooling once before heat treatment, reducing the temperature difference between stretching and heat treatment, etc. , it is preferable because the in-plane retardation and the main orientation axis become uniform in the width direction, and the usable product width can be large. Moreover, when extending|stretching temperature is made low, the orientation at the time of extending|stretching will stick easily, and in-plane retardation can be improved also by this. Conversely, if the temperature during stretching is increased, the in-plane retardation is difficult to increase because the molecules are stretched without being oriented. In this invention, in order to make an in-plane phase difference into substantially integer multiple of the wavelength of a light source, it is necessary to adjust a draw ratio and a extending|stretching temperature. However, since the draw ratio and the stretching temperature greatly affect important physical properties in using the film, such as the strength and elongation at break, of the film, it is difficult to make the strength and elongation at break of the film and the target in-plane retardation compatible. Therefore, as a method of adjusting in-plane retardation, it is preferable to use the film which laminated|stacked 5 or more layers of 2 or more types of resin alternately. It is because coexistence of the design of the intensity|strength of a film, break point elongation, and in-plane retardation becomes easy by adjusting the refractive index of resin to be used in addition to a draw ratio and extending|stretching temperature.

Further, in the authentication device of the present invention, it is preferable that PT(0) and PT(45) measured by the following method satisfy the following formulas (III) and (IV).

(III) PT(45)≥0.65

(IV) 1≥PT(45)/PT(0)≥0.6

[Method of measuring PT(0) and PT(45)]

(1) Measurement is performed using a spectrophotometer using a 50 W tungsten lamp as a light source.

(2) The polarizers are cut into two sheets and arranged so that the planes of the two polarizers are perpendicular to the optical axis of the spectrophotometer and the transmission axes of the two polarizers are parallel to each other.

(3) With respect to the two polarizers, the amount of transmitted light at a wavelength having the strongest intensity of the light emitted from the light source (background measurement) is measured. The amount of transmitted light in the light source turned off state obtained in the background measurement was taken as PT(D), and the transmitted light amount in the light source turned on state was defined as PT(L).

(4) The film is placed between the two polarizers so that the surface of the film is perpendicular to the optical axis of the spectrophotometer.

(5) While rotating only the film in a plane perpendicular to the optical axis of the spectrophotometer, the amount of transmitted light at a wavelength having the strongest intensity of light emitted from the light source is measured. When the angle between the transmission axes of the two polarizers and the main alignment axis of the film is 0°, the transmitted light amount is PT′(0), and the transmitted light amount when 45° is 45° is PT′(45).

(6) PT(0) and PT(45) are obtained from the following equations.

PT(0)=(PT'(0)-PT(D))/(PT(L)-PT(D))

PT(45)=(PT'(45)-PT(D))/(PT(L)-PT(D))

The PT 45 obtained above is interpreted as the transmittance when the PT 45 is affixed at an angle considered to have the lowest transmittance. Formula (III) has shown that it is preferable that the transmittance|permeability becomes 0.65 or more even if it is the state in which the transmittance|permeability fell most. When the transmittance becomes 0.65 or less, it may lead to the fall of authentication property.

PT(0) obtained above indicates transmittance when the orientation angle is 0°, that is, when the film is affixed at an ideal angle from the viewpoint of improving transmittance. The ratio (PT(45)/PT(0)) with PT(45) indicates the degree to which the transmittance decreases when the film pasting method deviates from the ideal angle. When the ratio of PT(0) and PT(45) is not within the above range, that is, if PT(45) is greater than PT(0) or PT(45) is too small compared to PT(0), that is, When PT(45)/PT(0) is smaller than 0.6, in order to improve the authenticity of the authentication device, it is necessary to install so that the transmission axis of the polarizer and the main orientation axis of the film are parallel to each other, and productivity is lowered. there may be cases More preferably, it is 0.75 or more and less than 1.0.

The film applicable to the present invention is a conventionally known general film forming method as long as the refractive index, draw ratio, and draw temperature of the resin can be adjusted, but it can be produced under specific film forming conditions. For example, a substantially amorphous, non-oriented, unstretched film can be produced by melting the resin used as the material by an extruder, extruding it with an annular die or T-die and quenching it. As described above, in order to achieve both control of in-plane retardation and improvement of film strength, it is also preferable to laminate two or more types of resins. From the same viewpoint, it is particularly preferable to include a structure in which two types of resins are alternately laminated in five or more layers. Furthermore, the unstretched film is further uniaxially stretched, tenter type sequential biaxial stretching, tenter type simultaneous biaxial stretching, tubular type simultaneous biaxial stretching, etc. , MD direction), or by extending|stretching in the direction (width direction, transverse axis direction, TD direction) perpendicular to the longitudinal direction of a film, the biaxially stretched film can be manufactured. Although the draw ratio in this case can be suitably selected according to the resin used as the raw material of a film, It is preferable to exist in the range of 2 to 10 times in a longitudinal direction and a transverse direction, respectively. In order to suppress the shrinkage at the time of processing as an authentication device, it is also preferable to heat-process after extending|stretching.

By forming into a film within the above conditions, the elongation at break at 25°C in the direction orthogonal to the main orientation axis and the main orientation axis of the film is 30% or more and 300% or less, handling property improvement at the time of processing and the film It is preferable from the viewpoint of improving the strength as It is more preferable that they are 50 % or more and 200 % or less. When the elongation at break is 30% or less, it is not preferable because the possibility of breakage during processing or damage to the surface of the authentication device increases. Moreover, when it exceeds 300 %, it may lead to the fall at the time of a process, and the fall of the authenticity by the flaw or recessed part by the intensity|strength as a film becoming low.

Moreover, as mentioned later, when installing in an authentication device, it is preferable that the transmission axis of a polarizer and the main orientation axis of a film are parallel from a viewpoint of transmittance|permeability, furthermore, authentication property. Therefore, it is preferable that the direction of the main orientation axis of a film is constant in the MD direction and TD direction of a film. The method of making the orientation angle constant is not particularly limited, For example, by increasing the draw ratio in the MD direction or the TD direction compared to the other draw ratio, 100° C. in the main orientation axis direction and in the direction orthogonal to the main orientation axis It is mentioned that the ratio (maximum/minimum value) of the maximum value and minimum value of the thermal contraction rate at the time of processing for 30 minutes is more than a fixed value. Preferably, the ratio of the maximum value to the minimum value is 1.7 or more, more preferably 2.0 or more, still more preferably 3.0 or more.

Although it is preferable to exist in the range of 3-200 micrometers as thickness of a film, More preferably, it exists in the range of 10-150 micrometers, Especially preferably, it exists in the range of 20-120 micrometers. By setting it in the said range, the thickness of the whole authentication device can be made thin, ensuring the intensity|strength required at the time of a process.

In addition, it is preferable that the angle between the main alignment axis of the film and the transmission axis of the polarizer is less than 10° from the viewpoint of suppressing the decrease in authenticity. When it exceeds 10 degrees, the range of the in-plane retardation with good authentication property narrows, and the fluctuation|variation of the in-plane retardation within a film plane may lead to the fall of authentication property. However, at the time of film formation, since the phenomenon of bowing described in Japanese Patent Application Laid-Open No. 2010-240976 occurs, the range in which the orientation angles are aligned to the extent that they do not affect the authenticity is limited, and the orientation angles are not aligned. A non-existent range is a production loss. In the film forming conditions of the present invention, by setting the longitudinal stretch ratio to 3.5 times or less, or/or the horizontal stretch ratio to 3.5 times or more, the direction of the main orientation axis becomes uniformly close over the wide width of the film, so from the viewpoint of productivity desirable. It is more preferable that the longitudinal stretch ratio be 3.2 times or less, and/or the transverse stretch ratio is 4 times or more, and it is particularly preferable that the longitudinal stretch ratio is 2.9 times or less, and/or the horizontal stretch ratio is 4.5 times or more. In addition, since it becomes easy to suppress the change of the orientation angle of the width direction by setting it as a film of a multilayer structure, it is preferable.

It is preferable that the said film used in the authentication device of this invention has a small nonuniformity of the in-plane retardation within a film plane from a viewpoint of nonuniformity reduction of an authentication property. As an evaluation method of non-uniformity, for example, both ends of a straight line film which is orthogonal to the straight line AB which connects the both ends (A, B) and the points A and B which show the maximum length in a film plane, and passes through the midpoint of the straight line AB. The method of measuring the in-plane phase difference of a total of 4 points|pieces of (C, D) is mentioned. It is preferable that the difference between the maximum and minimum of the obtained four points|pieces in-plane phase difference is 200 nm or less. It is more preferable that the difference of the said in-plane retardation is 150 nm or less, and it is especially preferable that it is 100 nm or less. Although the method is not specifically limited in order to make the in-plane retardation within the said range, It is preferable to stabilize the stress applied to a film as a whole by extending|stretching 2.7 times or more at a time at the time of film extending|stretching.

In addition, in order to prevent deterioration of the internal polarizer and light source, it is preferable that the film shields ultraviolet rays (here, light having a wavelength of 410 nm or less). When a light source is comprised by organic materials, such as OLED, especially the ultraviolet-ray shielding effect is desired. Although it is most preferable to completely block the light of 410 nm or less, it becomes possible to prevent deterioration of the internal polarizer and a light source by making the light transmittance of wavelength 380 nm into 5 % or less, for example. Although the method of shielding an ultraviolet-ray is not specifically limited, It is preferable to reflect an ultraviolet light by a multilayer structure. The setting of the reflection wavelength can be determined by the layer thickness of each layer of the multilayer laminated film, as described in Japanese Patent Laid-Open No. 2016-215643. In addition to reflection, an ultraviolet absorber may be used or may be used in combination with a reflection design.

As the ultraviolet absorber usable in the present invention, it is preferable to use a benzotriazole-based, benzophenone-based, benzoate-based, or triazine-based UV absorber having a molecular weight of 300 g/mol or more. One type of a ultraviolet absorber may be selected from these, and may use 2 or more types together. The molecular weight and the sublimation properties of additives including the UV absorber are related, and when an additive having a large molecular weight is used, sublimation is difficult to occur. The molecular weight is more preferably 400 g/mol or more, and still more preferably 500 g/mol or more. UV absorbers with high molecular weight often have long-chain alkyl chains attached to the basic aromatic ring backbone, and they inhibit the stacking of UV absorbers, crystallize in the resin and cause haze to increase. It is preferable because

Although the ultraviolet absorber that can be added is not specifically limited as a benzotriazole type ultraviolet absorber, For example, 2-(2'-hydroxy-5'-methylphenyl) benzotriazole, 2-(2'-hydroxy-3) ',5'-ditert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tertbutyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-( 2'-hydroxy-5'-tertiary octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole, 2-(2'-hydroxy- 2-(2'-hydroxyphenyl) such as 3'-tert-butyl-5'-carboxyphenyl)benzotriazole and 2,2'-methylenebis(4-tert-octyl-6-benzotriazolyl)phenol Benzotriazoles, etc. are mentioned.

Although it does not specifically limit as a benzophenone type|system|group ultraviolet absorber, For example, 2, 4- dihydroxybenzophenone, 2-hydroxy-4- methoxybenzophenone, 2-hydroxy-4- octoxybenzophenone, 5, 2-hydroxybenzophenones, such as 5'- methylenebis(2-hydroxy-4- methoxybenzophenone), are mentioned.

Although it does not specifically limit as a benzoate-type ultraviolet absorber, For example, phenyl salicylate, resorcinol monobenzoate, 2, 4- di tert-butylphenyl-3, 5- di tert-butyl-4-hydroxybenzoate, 2,4-ditertiary amylphenyl-3,5-ditertiary butyl-4-hydroxybenzoate, hexadecyl-3,5-ditertiary butyl-4-hydroxybenzoate, etc. are mentioned.

Although it does not specifically limit as a triazine type ultraviolet absorber, 2-(2-hydroxy-4- octoxyphenyl)-4,6-bis(2,4-dimethylphenyl)-s-triazine, 2-(2-hydroxy Roxy-4-hexyloxyphenyl)-4,6-diphenyl-s-triazine, 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-dimethyl Phenyl)-s-triazine, 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-dibiphenyl-s-triazine, 2,4-bis(2-hydroxy-4-octoxy) Phenyl)-6-(2,4-dimethylphenyl)-s-triazine, 2,4,6-tris(2-hydroxy-4-octoxyphenyl)-s-triazine, 2-(4-iso and triaryl triazines such as octyloxycarbonylethoxyphenyl)-4,6-diphenyl-s-triazine.

As other ultraviolet absorbers, salicylic acid-based agents include, for example, phenyl salicylate, t-butylphenyl salicylate, p-octylphenyl salicylate, and other natural products (eg, oryzanol, shea butter, baicalin, etc.). ), biological systems (eg, keratinocytes, melanin, urocanin, etc.) can also be used. A hindered amine compound can also be used together with these ultraviolet absorbers as a stabilizer. The inorganic ultraviolet absorber is not compatible with the base resin, leading to a rise in haze, and is undesirable because it deteriorates visibility when an image is displayed on an authentication device.

When using a ultraviolet absorber, you may add to A-layer containing the outermost layer of the laminated|stacked biaxially oriented film which is a preferable aspect of this invention, or B-layer which is an inner layer, or both. Especially, it is most preferable to contain a ultraviolet absorber only in B-layer. When an ultraviolet absorber is added to the outermost layer, a phenomenon in which the added ultraviolet absorber is precipitated on the film surface and a phenomenon in which it is volatilized easily occur, thereby contaminating the film forming machine, and the precipitate exerts a bad influence on the processing process That's why it's undesirable. By adding it only to the inner layer, since the outermost layer serves as a cover for preventing volatilization of the ultraviolet absorber, it is preferable because the precipitation phenomenon does not occur easily.

You may apply the coating which provides functionality, such as scratch resistance, to the film surface. As a coating method, the method of having curable resin as a main component, adding crosslinking agents, such as a melamine oxazoline, and hardening by ultraviolet light can be used.

The curable resin is preferably highly transparent and durable. For example, an acrylic resin, a urethane resin, a fluorine-based resin, a silicone resin, a polycarbonate-based resin, or a vinyl chloride-based resin can be used alone or in combination. In particular, it is preferable that curable resin contains active energy ray-curable resin, such as an acrylic resin typified by polyacrylate resin, from the point of sclerosis|hardenability, flexibility, and productivity. In addition, when adding abrasion resistance at the time of bending required to a film applied to a site requiring curved followability, the curable resin preferably includes a thermosetting urethane resin.

In addition, when the authentication device targets the distribution pattern of the melanin pigment present in the epidermis, for example, since the melanin pigment strongly absorbs blue light from ultraviolet light, the light source wavelength is blue light (the wavelength of the maximum peak is 415 nm or more and 495 nm or less) ), and that the in-plane retardation of the film is in the range of ±120 nm from an integer multiple of the wavelength of the light source, that is, the presence of an integer n satisfying the following formula (V) is preferable from the viewpoint of obtaining a clear pattern. When the wavelength of the light source is shorter than 415 nm, there is a case where the deterioration of the light source due to ultraviolet rays or the misrecognition due to the increase in absorption by other than melanin pigment becomes a problem.

(V) Axn-120≤Re≤Axn+120, and 415≤A≤495.

In addition, when the distribution pattern of hemoglobin is to be recognized, for example, as in vein authentication, since hemoglobin has a strong absorption peak in the infrared region, the wavelength of the light source is in the infrared region (the wavelength of the maximum peak is 800 nm or more and 1200 nm or less). , that the in-plane retardation of the film is in the range of ±150 nm from an integer multiple of the wavelength of the light source, that is, the presence of an integer n satisfying the following formula (VIII) is preferable from the viewpoint of obtaining a clear pattern. In addition, in the case of retina, iris, face authentication, etc., since the authentication target directly sees the light, it is sometimes preferable to use infrared rays from the viewpoint of alleviating the discomfort of the authentication target.

(VIII) Axn-150≤Re≤Axn+150, and also 800≤A≤1200.

Similarly, in some cases, it is preferable that the wavelength of the light source is green (the wavelength of the maximum peak is 495 nm or more and 570 nm or less), ie, an integer n satisfying the following formula (VI) is present due to the color or designability of the object to be authenticated. In addition, it is sometimes preferable that there is an integer n that satisfies the following formula (VII), that is, yellow to red (the wavelength of the maximum peak is 570 nm or more and 800 nm or less).

(VI) A×n-100≦Re≦A×n+100, and also 495≦A≦570.

(VII) Axn-120≤Re≤Axn+120, and 570≤A≤800.

Combining a plurality of the above wavelengths is also effective for improving the authentication accuracy, but in order to obtain the effect of the present invention, the in-plane retardation of the film is made to be approximately a common multiple of the wavelengths of each light source used, or different for each light source. It is preferable to use a film of in-plane retardation.

The area of the region that can be authenticated in the authentication device of the present invention is not particularly limited, and is appropriately adjusted according to the object to be authenticated or the use. Since the authentication device of the present invention uses a film having a uniform in-plane retardation and a main orientation axis, the area of a region that can be authenticated can be large. That is, the authentication device of the present invention can be suitably used for a device, the area of certifiable area than 100cm ² or more, further 225cm ² or more, and even 400cm ^2.

As described above, the authentication device of the present invention is capable of recognizing various authentication objects with high precision, so that at least one of a fingerprint, an iris, a face, a hand shape, a body shape, and a vein is used as an authentication device for authentication. can be used appropriately. Moreover, since the authentication device of this invention can make the authentication precision favorable even if the angle which the transmission axis of a polarizer and the main orientation axis of a film make is large, a yield can be reduced.

[Method for evaluating characteristics]

evaluation of the film

A. Difference between in-plane phase difference (Re) and in-plane phase difference (Δphase difference)

The in-plane phase difference and slow axis of the wavelength 587.8nm in 0 degree of incidence angle were measured using the Oji Scientific Instruments Co., Ltd. product, "KOBRA-21ADH". The direction of the slow axis was set as the main orientation axis. The sample was moved from the film, cut out to 5 places x 4 cm x 4 cm, and the average value measured was used for each.

The non-uniformity of the in-plane retardation is orthogonal to the straight line AB connecting the both ends (A, B) and the points A and B indicating the maximum length in the film plane, and the both ends of the straight film (C, The in-plane phase difference of a total of 4 points|pieces of D) was measured, and the difference between a maximum value and a minimum value was used.

B. PT(45) and PT(0)

(1) A polarizer used in the authentication device or a polarizer having a polarization degree equivalent to the polarizer being used (TS wire grid polarizing film (Edmund Opticus Japan Co., Ltd.)) is cut into two sheets, and the surfaces of the two polarizers are The 50W tungsten lamp is arranged so as to be perpendicular to the optical axis of the spectrophotometer as the light source and the transmission axes of the two polarizers are parallel to each other, and background measurement is performed in the light source off state and the light source on state. Let PT(D) be the amount of transmitted light measured when the light source is turned off, and PT(L) be the amount of transmitted light measured when the light source is on.

(2) The film is placed between two polarizers so that the surface of the film is perpendicular to the optical axis of the spectrophotometer.

(3) While rotating only the film in a plane perpendicular to the optical axis of the spectrophotometer, the amount of transmitted light at a wavelength having the strongest intensity of light emitted from the light source is measured. When the angle between the transmission axes of the two polarizers and the main alignment axis of the film is 0°, the transmitted light amount is PT′(0), and the transmitted light amount when 45° is 45° is PT′(45).

(4) PT(0) and PT(45) are obtained from the following equations.

PT(0)=(PT'(0)-PT(D))/(PT(L)-PT(D))

PT(45)=(PT'(45)-PT(D))/(PT(L)-PT(D))

C. Light source light transmittance and 380nm transmittance

The transmittance|permeability in incident angle = 0 degree was measured using the Hitachi High-Technologies Co., Ltd. product spectrophotometer (U-4100 Spectrophotometer).

Measurement conditions: The slit was set to 2 nm, the gain was set to 2, and the scanning speed was 600 nm/min. The sample was moved from the film, cut out to 5 places x 4 cm x 4 cm, and the average value measured for each was used.

The reflector of the integrating sphere uses aluminum oxide, the light metering method is a double beam direct ratio metering method, and the spectrometer uses a prism and grating/grating type double monochrome.

The light source light transmittance indicates transmittance at a wavelength having the strongest intensity of light emitted from the light source of the authentication device.

D. Elongation at break

The film was cut out to 10 mm width x 150 mm width from the center part of the sample width. Measurement was performed according to JIS-C-2151 and ASTM-D-882 using a digital micrometer (HKT-1208 manufactured by Matsuo Sangyo) and a tensile tester (RTG1210). The strength (the value of the tensile load divided by the cross-sectional area of the test piece) and the elongation when gripped with a chuck in the direction of the main orientation axis, tensioned at a speed of 200 mm/min, and the sample was cut (broken), and elongation were determined. The tensile elongation was calculated by the following formula.

Tensile elongation (%) = 100 × (L-Lo)/Lo

Lo: sample length before test L: sample length at break

The measurement was performed 5 times, and the average value was used. Similarly, the elongation at break in the direction orthogonal to the main orientation axis was also measured. The measurement was performed in a room maintained at 25°C.

E. Light source wavelength and light source half width

An optical fiber of NA0.22 was installed in a mini spectrophotometer (C10083MD, C9914GB) manufactured by Hamamatsu Photonics, and the light from the light source was measured. The wavelength having the highest intensity in the range of 320 nm or more and 1500 nm or less is the wavelength of the light source, and the width of the peak at half the intensity of the peak of the wavelength of the light source is the half width.

F. Thickness

Using a digital micrometer (HKT-1208 manufactured by Matsuo Sangyo), the film center portion was measured according to JIS-C-2151. The measurement was performed 3 times, and the average value was used.

Evaluation of authentication devices

G. Authenticity

In an environment of 23°C and 65RH%, the object to be authenticated α is registered. In the case of Example 10, the iris, and in other cases, the fingerprint is the object of authentication. After that, the authentication device is made to recognize the authentication object α and the unregistered authentication object β alternately 200 times. The recognition time is set to 2 seconds each. The probability of rejecting α (self rejection rate: FRR) and the probability of accepting β (other person acceptance rate: FAR) are evaluated as follows. A is good, B is possible, and C and D are unsuitable.

A: FRR≤1.0%, FAR≤0.5%

B: 1.0%<FRR≤3.0%, FAR≤0.5%

C: 3.0%<FRR≤5.0% or/or 0.5%<FAR≤1.0%

D: 5.0%<FRR or 1.0%<FAR.

H. Light source durability

The authentication device was maintained in the light source lighting state for 1000 hours in 23 degreeC 65RH% atmosphere, and the change of the authentication performance before and behind a test was evaluated. The judgment criteria are as follows. However, ΔFRR and ΔFAR represent values obtained by subtracting FRR and FAR before the test from the FRR and FAR after the test, respectively.

A: ΔFRR=0, also ΔFAR=0.

B: "0<ΔFRR≤1.0, and 0<ΔFAR≤0.5"

C: "1.0<ΔFRR≤2.0, further 0<ΔFAR≤0.5", "0<ΔFRR≤1.0, further 0.5<ΔFAR≤1.5" or "1.0<ΔFRR≤2.0, further 0.5<ΔFAR≤1.5"

D: It does not correspond to any of A, B, or C.

I. Impact resistance

The impact value was measured by a film impact tester (manufactured by Toyo Seiki Seisakusho) in an atmosphere of a temperature of 23°C and a humidity of 65% RH using a hemispherical impact head having a diameter of 1/2 inch. The measurement was performed 5 times with respect to 1 sample. In addition, the impact value for every time was divided by the film thickness attached to the measurement sample, it was set as the impact value per unit thickness, and it calculated|required from the average value of 5 measurements. From the measured values, it was evaluated as follows.

A: 1.0N·m/mm or more

B: 0.5 N·m/mm or more and less than 1.0 N·m/mm

C: Less than 0.5 N·m/mm.

J: heat shrinkage

For each of the MD and TD directions of the film, 5 samples with a width of 10 mm and a length of 200 mm (measurement direction) were cut out, marked as marked lines at 25 mm from both ends, and the distance between the marked lines was measured with a universal projector, and the test piece Let it be length (10). Next, the test piece is inserted into paper and taken out after heating for 30 minutes in an oven kept at 100° C. in a state of zero load, and after cooling at room temperature, the dimension 11 is measured with a universal projector to obtain the following equation, The average value was made into thermal contraction rate.

Thermal shrinkage = {(10-11)/10} × 100 (%)

Example

Hereinafter, although an Example is given and demonstrated about this invention, this invention is not necessarily limited to these.

(Example 1)

As the light source and the light sensitivity sensor, ClearID FS9500 made by Synaptics (light source wavelength 525 nm, light source half width 30 nm) was used.

As the polarizer, VF-PS#7500 made by Kuraray was used as a general polarizing film having a polarization degree of 80% or more. The film was produced by the following method.

(resin used to make the film)

Resin A: polyethylene terephthalate (PET) (intrinsic viscosity: 0.65)

Resin B: Polyethylene terephthalate (PET/SPG/CHDC) copolymerized with 25 mol% of spiroglycol with respect to the entire diol component and 30 mol% of cyclohexanedicarboxylic acid with respect to the entire dicarboxylic acid component (intrinsic viscosity: 0.72)

Resin C: Resin B (90% by weight) and 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl as an ultraviolet absorber) ) phenol] (10% by weight) was mixed using an extruder and pelletized.

Resin D: Resin A (90% by weight) and 2,2'-methylenebis[6-(2H-benzotriazol-2-yl)-4-(1,1,3,3-tetramethylbutyl as an ultraviolet absorber) ) phenol] (10% by weight) was mixed using an extruder and pelletized.

Resin E: Polyethylene terephthalate (PET) containing 0.8% by weight of divinylbenzene/styrene copolymer particles having an average particle diameter of 0.70 μm and 1.5% by weight of aggregated alumina particles having an average secondary particle diameter of 0.08 μm (intrinsic viscosity: 0.65).

(production of film)

Resin A was used as the resin constituting the layer A, and the resin C was used as the resin constituting the layer B. In addition, the intrinsic viscosity of this resin C was an amorphous resin of 0.72, and the in-plane average refractive index after film-forming was 1.55. Thermoplastic resin A and thermoplastic resin C were melted at 280°C with an extruder, respectively, and 5 FSS type leaf disc filters were interposed, and then the discharge ratio (stacking ratio) was resin A/resin C=1.5/1 with a gear pump. and, while measuring so that the film thickness after biaxial stretching might be set to 35 micrometers, it was made to join alternately with a 201 layer feed block (A layer 101 layers, B layer 100 layers). Then, it was supplied to a T-die, molded into a sheet, and then quenched and solidified on a casting drum maintained at a surface temperature of 25° C. while applying an electrostatic applied voltage of 8 kV with a wire to obtain an unstretched multilayer laminated film. This unstretched film was sequentially biaxially stretched. First, after conveying with a Teflon (trademark) roll at 105 degreeC, it extended|stretched 2.8 times at 95 degreeC, heating with the infrared heater which made the output 500W in the longitudinal direction, and obtained the uniaxially stretched film. This uniaxially stretched film is stretched 4.5 times at 100° C. in the width direction in a tenter, and then heat-set at 220° C., then relaxes 1.7% in the width direction at that time, is cooled in the conveying step, and the edge is wound after cutting. got a film. The physical properties of the obtained film are shown in Tables 1 and 3.

(Production of authentication device)

ClearID (light source, photosensitive sensor), a polarizer, and a film were adhered using an optically clear adhesive (OCA: Optically Clear Adhesive) in this order to obtain an authentication device. At that time, it arrange|positioned so that the main orientation axis of a film may become parallel with the transmission axis of a polarizer. The authenticable area of the authentication device was 1 cm ² . Tables 2 and 4 show the characteristics of the obtained authentication device. An authentication device having excellent authentication properties and durability was obtained.

(Example 2)

An authentication device was obtained in the same manner as in Example 1 except that the main orientation axis of the film affixed on the device was 45° with respect to the transmission axis of the polarizer. As shown in Table 2, an authentication device having excellent authentication properties and durability was obtained.

(Example 3)

Except having made the draw ratio of the width direction into 5.5 times, it carried out similarly to Example 2, and obtained the film and the authentication device. An authentication device having excellent authentication properties and durability was obtained.

(Example 4)

A film and an authentication device were obtained in the same manner as in Example 1 except that the draw ratio in the longitudinal direction was set to 3.0. An authentication device having excellent authentication properties and durability was obtained.

(Example 5)

An authentication device was obtained in the same manner as in Example 4 except that the main orientation axis of the film was set to 10° with respect to the transmission axis of the polarizer. An authentication device having good authentication properties and excellent durability was obtained.

(Example 6)

An authentication device was obtained in the same manner as in Example 4 except that the main orientation axis of the film was 45° with respect to the transmission axis of the polarizer. An authentication device having good authentication properties and excellent durability was obtained.

(Example 7)

Except for making the draw ratio of the longitudinal direction into 2.6 times, it carried out similarly to Example 2, and obtained the film and the authentication device. An authentication device having good authentication properties and excellent durability was obtained.

(Example 8)

Except using resin D as resin which comprises B-layer, it carried out similarly to Example 2, and obtained the film and the authentication device. An authentication device having good authentication properties and durability was obtained.

(Example 9)

The film and the authentication device were obtained like Example 2 except the temperature at the time of extending|stretching in a longitudinal direction into 90 degreeC and the temperature at the time of extending|stretching in a width direction into 120 degreeC. An authentication device having good authentication properties and excellent durability was obtained.

(Example 10)

A film and an authentication device were obtained in the same manner as in Example 2 except that BM ET-200 made by Panasonic was used as a light source and a light sensitivity sensor instead of ClearID, and the stretch ratio in the longitudinal direction was increased to 3.2. An authentication device having excellent authentication properties and durability was obtained.

(Example 11)

A film and an authentication device were obtained in the same manner as in Example 2 except that a three-layer feed block (A layer was two outer layers and B was an inner one layer). It has become an authentication device having excellent authentication properties.

(Example 12)

Except using resin B as resin which comprises B-layer, it carried out similarly to Example 2, and obtained the film and the authentication device. It has become an authentication device having excellent authentication properties.

(Example 13)

A film and an authentication device were obtained in the same manner as in Example 2 except that the draw ratio in the longitudinal direction was 1.05 times and the draw ratio in the width direction was 1.05 times, and the heat treatment was not performed. It has become an authentication device having excellent authentication properties.

(Example 14)

A film and an authentication device were obtained in the same manner as in Example 2 except for using a polycarbonate film (Panlite PC-7129 manufactured by Teijin) as the film. It has become an authentication device having excellent authentication properties.

(Example 15)

An authentication device was obtained in the same manner as in Example 1 except that the authenticateable area was 50 cm ^{2 .} It has become an authentication device having excellent authentication properties.

(Example 16)

Except for making the draw ratio of the longitudinal direction into 4.2 times and the draw ratio of the width direction into 2.3 times, it carried out similarly to Example 15, and obtained the film and the authentication device. It has become an authentication device with good authentication properties.

(Example 17)

Except having made the draw ratio of the width direction into 4.4 times, it carried out similarly to Example 1, and obtained the film and the authentication device. In addition, while measuring this film by setting the light source wavelength as 587.8 nm when measuring the in-plane retardation, it measured also as the light source wavelength to 525 nm with a color filter. The results measured at 525 nm are shown in parentheses in the column of Re (nm) in Table 3. As shown in Table 4, an authentication device having particularly excellent authenticity with FRR = 0% in the authenticity test was obtained.

(Example 18)

Except having made the draw ratio of the width direction into 4.4 times, it carried out similarly to Example 2, and obtained the film and the authentication device. In addition, while measuring this film as 587.8 nm of light source wavelengths when measuring in-plane retardation, it measured also as 525 nm of light source wavelengths with a color filter. The results measured at 525 nm are shown in parentheses in the column of Re (nm) in Table 3. As shown in Table 4, an authentication device having particularly excellent authenticity with FRR = 0% in the authenticity test was obtained.

(Example 19)

An authentication device was obtained in the same manner as in Example 2 except that the ClearID light source and photosensitive sensor and the light source and photosensitive sensor of BM ET-200 were used simultaneously. In ClearID and BM ET-200, the intensity of light from the light source was higher in ClearID. Only the data from ClearID's light sensitivity sensor became an authentication device with excellent authenticity. Among the measurement items in Tables 3 and 4, the measurement results at 525 nm are described outside the parentheses, and the results at 850 nm are described in the parentheses for the items in which the light source wavelength is required for measurement.

(Example 20)

Except having made the draw ratio of the width direction into 5.7 times, it carried out similarly to Example 19, and obtained the film and the authentication device. In ClearID and BM ET-200, the intensity of light from the light source was higher in ClearID. Data from either the ClearID optical sensitivity sensor or the BM ET-200 optical sensitivity sensor became an authentication device having excellent authentication properties. Among the measurement items in Tables 3 and 4, the measurement results at 525 nm are described outside the parentheses, and the results at 850 nm are described in the parentheses for the items in which the wavelength of the light source is required for measurement.

(Example 21)

A film and an authentication device were obtained in the same manner as in Example 5 except that the heat treatment temperature was set to 240°C. As shown in Table 4, an authentication device having good authentication properties was obtained.

(Example 22)

Except for making the draw ratio of the longitudinal direction into 2.6 times and the draw ratio of the width direction into 4.0 times, it carried out similarly to Example 2, and obtained the film and the authentication device. As shown in Table 4, although the variation in the in-plane phase difference is slightly large, the authentication device as a whole has good authenticity.

(Example 23)

Except using resin E instead of resin A, it carried out similarly to Example 5, and obtained the film and an authentication device. As shown in Table 4, an authentication device having good authentication properties was obtained.

(Example 24)

A film and an authentication device were obtained in the same manner as in Example 2 except for using a 9-layer feed block (A layer was 5 outer layers and B layer was inner 4 layers). As shown in Table 4, an authentication device having excellent authentication properties was obtained.

(Example 25)

A film and an authentication device were prepared in the same manner as in Example 2 except that a 101-layer feed block (A layer was 51 layers on the outer side, B layer was an inner layer of 50 layers), and the discharge amount was adjusted and the thickness after stretching was set to 18 µm. got it Although the impact resistance is slightly lowered by thinning, it became a film applicable also to the use which a thin film is requested|required. As shown in Table 4, an authentication device having excellent authentication properties was obtained.

(Comparative Example 1)

A film and an authentication device were obtained in the same manner as in Example 2 except that the draw ratio in the longitudinal direction was 3.2 times and the main orientation axis of the film was 10° with respect to the transmission axis of the polarizer. It has become an authentication device with slightly inferior authenticity.

(Comparative Example 2)

Except having made the draw ratio of the longitudinal direction into 3.2 time, it carried out similarly to Example 2, and obtained the film and the authentication device. It has become an authentication device with poor authenticity.

(Comparative Example 3)

Except having made the draw ratio of the width direction into 4.9 times, it carried out similarly to Example 2, and obtained the film and the authentication device. It has become an authentication device with poor authenticity.

(Comparative Example 4)

A film and an authentication device were obtained in the same manner as in Comparative Example 2 except that the draw ratio in the longitudinal direction was 3.2 times and the draw ratio in the width direction was 4.4 times. It has become an authentication device with poor authenticity.

In the authentication device of the present invention, the authentication performance does not depend on the orientation angle of the film, and the film absorbs and reflects ultraviolet rays, thereby increasing the durability of the light source and the polarizer, and can use inexpensive polyester as a raw material for the film. Therefore, it has favorable authentication performance and durability, and is inexpensive and is excellent in productivity.

1: light source
2: Polarizer
3: film
4: light sensitivity sensor
5: The light emitted from the light source is reflected from the object to be authenticated
6: Light emitted from the light source

Claims (20)

An authentication device comprising a light source, a polarizer, a film, and a light sensitivity sensor, wherein the film is disposed between the polarizer and an object to be authenticated, and the following (1) and (2) are satisfied.
(1) The transmittance|permeability of the light source emitted from the said light source is 70% or more and 100% or less in the wavelength of the strongest intensity|strength of the said light source.
(2) An integer n satisfying the following formula (I) exists.
(I) A×n-150≤Re≤A×n+150
Here, A is the wavelength (nm) showing the strongest intensity in the light emitted from the light source,
Re is the in-plane retardation (nm) of the film measured at a wavelength of 587.8 nm at an incident angle of 0° using a parallel Nicol rotation method. The authentication device according to claim 1, wherein an integer m that satisfies the following formula (II) while satisfying the above expression (I) exists.
(II) B×m-150≤Re≤B×m+150
Here, B is the wavelength (nm) showing the second strongest intensity in the light emitted from the light source,
Re is the in-plane retardation (nm) of the film measured at a wavelength of 587.8 nm at an incident angle of 0° using a parallel Nicol rotation method. The authentication device according to claim 1 or 2, wherein the film satisfies the following formulas (III) and (IV).
(III) PT(45)≥0.65
(IV) 1≥PT(45)/PT(0)≥0.6
Here, PT(45) and PT(0) are obtained as follows.
(1) The polarizers are cut into two pieces, and the planes of the two polarizers are arranged so that they are perpendicular to the optical axis of a spectrophotometer using a 50W tungsten lamp as a light source, and the transmission axes of the two polarizers are parallel to each other, and the light source Background measurement is performed in the off state and in the light source on state. Let PT(D) be the amount of transmitted light measured when the light source is turned off, and PT(L) be the amount of transmitted light measured when the light source is on.
(2) The film is placed between two polarizers so that the surface of the film is perpendicular to the optical axis of the spectrophotometer.
(3) While rotating only the film in a plane perpendicular to the optical axis of the spectrophotometer, the amount of transmitted light at a wavelength having the strongest intensity of light emitted from the light source is measured. When the angle between the transmission axes of the two polarizers and the main alignment axis of the film is 0°, the transmitted light amount is PT′(0), and the transmitted light amount when 45° is 45° is PT′(45).
(4) PT(0) and PT(45) are obtained from the following equations.
PT(0)=(PT'(0)-PT(D))/(PT(L)-PT(D))
PT(45)=(PT'(45)-PT(D))/(PT(L)-PT(D)). The authentication device according to any one of claims 1 to 3, wherein the half-width of the peak showing the strongest intensity in the light emitted from the light source is 5 nm or more and 70 nm or less. The authentication device according to any one of claims 1 to 4, wherein an integer n satisfying the following expression (V) exists.
(V) Axn-120≤Re≤Axn+120, and 415≤A≤495. The authentication device according to any one of claims 1 to 4, wherein an integer n satisfying the following formula (VI) exists.
(VI) A×n-100≦Re≦A×n+100, and also 495≦A≦570. The authentication device according to any one of claims 1 to 4, wherein an integer n satisfying the following formula (VII) exists.
(VII) Axn-120≤Re≤Axn+120, and 570≤A≤800. The authentication device according to any one of claims 1 to 4, wherein an integer n satisfying the following formula (VIII) exists.
(VIII) A×n-150≦Re≦A×n+150, and also 800≦A≦1600. The authentication device according to any one of claims 1 to 8, wherein the in-plane retardation of the film is 400 nm or more and 3000 nm or less. The authentication device according to any one of claims 1 to 9, wherein the film is a laminated film in which five or more layers are alternately laminated with a layer containing a resin A and a layer containing a resin B different from the resin A. The polyester according to claim 10, wherein the resin B constituting the film contains at least one selected from cyclohexanedimethanol, spiroglycol, neopentylglycol, isophthalic acid, cyclohexanedicarboxylic acid, and isosorbide. An authentication device, characterized in that it has as a main component. The authentication device according to any one of claims 1 to 11, wherein the elongation at break at 25°C in the main orientation axis direction and the direction orthogonal to the main orientation axis of the film are 30% or more and 300% or less. The ratio of the maximum to the minimum of the thermal contraction rate according to any one of claims 1 to 12, wherein the film is treated at 100° C. for 30 minutes in the direction orthogonal to the main orientation axis and the main orientation axis (maximum value / Authenticated devices with a minimum value of 1.7 or higher. The authentication device according to any one of claims 1 to 13, wherein an angle between the main alignment axis of the film and the transmission axis of the polarizer is less than 10°. 15. The film according to any one of claims 1 to 14, wherein the film is orthogonal to a straight line AB connecting both ends (A, B) and points A and B representing the maximum length in the film plane, and An authentication device whose difference between the maximum value and the minimum value is 200 nm or less in a total of four points of in-plane retardation of both ends (C, D) of a straight film passing through a midpoint. The authentication device according to any one of claims 1 to 15, wherein the area of the authenticable area is 10 cm ² or more. The light source according to any one of claims 1 to 16, wherein the light source contains any one of an organic EL (organic electroluminescent element) and a light emitting diode (LED), and the light transmittance of the film at a wavelength of 380 nm is 5% The following authentication devices. 18. The authentication device according to any one of claims 1 to 17, wherein the photosensitive sensor is a complementary metal-oxide-semiconductor (CMOS) sensor. A film used for an authentication device having a light source, a polarizer, a film, and a photosensitive sensor, and satisfying the following (1) and (2).
(1) In the said film, the transmittance|permeability of the light ray emitted from the said light source is 70 % or more and 100 % or less in the wavelength of the strongest intensity|strength of the said light ray.
(2) An integer n satisfying the following formula (I) exists.
(I) A×n-150≤Re≤A×n+150
Here, A is the wavelength (nm) showing the strongest intensity in the light emitted from the light source,
Re is the in-plane retardation (nm) of the film measured at a wavelength of 587.8 nm at an incident angle of 0° using a parallel Nicol rotation method. The film according to claim 19, wherein the film satisfies the following formulas (III) and (IV).
(III) PT(45)≥0.65
(IV) 1≥PT(45)/PT(0)≥0.6
Here, PT(45) and PT(0) are obtained as follows.
(1) The polarizers are cut into two sheets, and the planes of the two polarizers are arranged so that they are perpendicular to the optical axis of the spectrophotometer using a 50W tungsten lamp as a light source, and the transmission axes of the two polarizers are parallel to each other, and the background Take measurements. Let PT(D) be the amount of transmitted light measured when the light source is turned off, and PT(L) be the amount of transmitted light measured when the light source is on.
(2) The film is placed between two polarizers so that the surface of the film is perpendicular to the optical axis of the spectrophotometer.
(3) While rotating only the film in a plane perpendicular to the optical axis of the spectrophotometer, the amount of transmitted light at a wavelength showing the strongest intensity in the light emitted from the light source is measured. When the angle between the transmission axes of the two polarizers and the main alignment axis of the film is 0°, the transmitted light amount is PT′(0), and the transmitted light amount when 45° is 45° is PT′(45).
(4) PT(0) and PT(45) are obtained from the following equations.
PT(0)=(PT'(0)-PT(D))/(PT(L)-PT(D))
PT(45)=(PT'(45)-PT(D))/(PT(L)-PT(D)).

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