JP2006071633A - Method and member for testing optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and member for testing optical films which accurately determine quality of optical films. <P>SOLUTION: The testing member for optical films 10 is equipped with a base material 11 and a jointing material 12, laminated on one face 11a of the base material 11, characterized in that, at least either one of these base material 11 and the jointing material 12 has masking effect. The optical film 20 adheres on the jointing material 12 of the testing member for optical films 10 so as to be irradiated with light on the surface thereon, then the reflected light of which is observed, to determine the quality level of the optical film 20. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an optical film inspection member and an optical film inspection method.

  In recent years, an optical film has been used on the surface of a polarizing plate incorporated in the forefront of a liquid crystal display or the like. This optical film is an anti-glare film or anti-reflection film that prevents the LCD screen from being scratched and makes it easier to see the LCD screen by reducing the glare and glare from sunlight, external light, fluorescent light, etc. It is used to Also, an antireflection film for PDP is used as an optical film on the outermost surface of PDP (Plasma Display Panel).

As described above, when the optical film is used for a liquid crystal display or the like, if there are bubbles or foreign substances inside the polarizing film, the display characteristics are hindered.
Therefore, a method for inspecting whether there is an abnormality in the optical film has been proposed (for example, see Patent Document 1). In the inspection method described in Patent Document 1, an object to be inspected such as a film is placed on a black plate, the object to be inspected is irradiated with light, and reflected light of the irradiated light is photographed with an imaging device. This is a method for detecting a defective portion of an object to be inspected.
There has also been proposed a method in which black ink is applied to one surface of an optical film, light is irradiated from the other surface of the optical film, and reflected light is observed.
In addition, a polarizing plate that is in a crossed nicols state by overlapping two polarizing plates so that the polarization axis directions are orthogonal to each other is bonded to one surface of the optical film, and the light is irradiated in the same manner, and the reflected light is observed. A method to do this is also proposed.
JP-A-6-288927

However, in the film inspection method described in Patent Document 1, an air layer is formed between the film and the black plate, and extra disturbance light is generated by the air layer, so that the inspection accuracy is inferior. .
On the other hand, when black ink is applied, uneven coating occurs, and it is difficult to determine whether it is a defect inside the optical film or uneven coating. Further, since the optical film is eroded by the solvent of the black ink, it cannot be stored for a long time. Furthermore, there is a problem that the site is contaminated with black ink.
On the other hand, when laminating a polarizing plate with a polarizing plate on one side of an optical film, it is difficult to bond the polarizing plate so that it is in a crossed Nicol state, resulting in instability in quality. End up. Moreover, the polarizing plate bonded to crossed Nicols is usually difficult to use due to large dimensional restrictions. Therefore, the cost required for the inspection is also increased.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide an optical film inspection member and an optical film inspection method capable of accurately determining the quality of an optical film. To do.

In order to achieve the above object, the present invention provides the following means.
The inspection member for an optical film of the present invention includes a base material and an adhesive member laminated on the base material, and at least one of the base material and the adhesive member is a light shielding member.

  The optical film inspection member of the present invention is an optical film inspection method using the above-described optical film inspection member, the step of adhering the optical film on the adhesive member, and the surface of the optical film with light. A step of irradiating, a step of observing reflected light from the optical film, and a step of judging the quality of the optical film based on the result of observing the reflected light.

  ADVANTAGE OF THE INVENTION According to this invention, the inspection member for optical films and the inspection method of an optical film which can judge the quality of an optical film accurately can be provided.

  Since the inspection member for an optical film according to the present invention includes a base material and an adhesive member laminated on the base material, the optical film and the base material can be brought into close contact with each other via the adhesive member. Therefore, when the surface of the optical film is irradiated with light, generation of extraneous disturbance light is suppressed, and only the light reflected by the optical film can be detected. In addition, since at least one of the base material and the adhesive member is a light-shielding member, coating unevenness cannot occur as in the conventional case, so that the inspection can be performed with light completely blocked, and the inspection accuracy is improved. In addition, since the configuration is simple, the cost required for inspection can be reduced.

Further, according to the optical film inspection method of the present invention, using the optical film inspection member having the above-described configuration, the step of adhering the optical film on the adhesive member, and irradiating the surface of the optical film with light A step of observing the reflected light from the optical film, and a step of judging the quality of the optical film based on the result of observing the reflected light, so that the quality of the optical film is accurately inspected. Is possible. Moreover, since it is a simple inspection process, the inspection efficiency of the optical film is also improved.
Each said process can be performed by the method generally used, for example, the process of irradiating the surface of the said optical film uses the inspection apparatus conventionally used in order to test | inspect an optical film. Can be done.

Hereinafter, with reference to FIG. 1 and FIG. 2, an embodiment of the inspection member for an optical film of the present invention (hereinafter sometimes simply referred to as an inspection member) and an optical film using the inspection member 10 according to the embodiment. 20 inspection methods will be described.
As shown in FIG. 1, the inspection member 10 for an optical film according to the present embodiment is disposed on a base material 11 made of a light shielding member that blocks light transmission, and one surface 11 a of the base material 11. And an adhesive member 12 for adhering the light shielding member 11 to each other.

In the present invention, at least one of the base material 11 and the adhesive member 12 needs to be a light shielding member. Thereby, it can test | inspect by blocking | blocking light uniformly, and can test | inspect an optical film with the outstanding test | inspection precision. In particular, it is preferable that the adhesive member 12 that is in direct contact with the optical film is a light-shielding member because inspection accuracy is particularly good, and among them, both the base material 11 and the adhesive member 12 are preferably light-shielding members.
The light shielding member is particularly preferably a black light shielding member. As a result, the crossed Nicol state can be simulated, and the inspection accuracy is further improved.
When one of the base material 11 and the adhesive member 12 is not a light-shielding member, the base material 11 or the adhesive member 12 that is not a light-shielding member may be a light-transmissive member that transmits light, for example, transparent or translucent It may be.

  The shape of the base material 11 may be any shape as long as it can be arranged in a flat state at the time of inspection, and may be, for example, a film shape or a plate shape. In particular, the film shape is preferable because the inspection member can be formed in a scroll shape. When the inspection member is in the form of a scroll, it is very convenient because an inspection sample of a free size can be made according to the size of the optical film.

There is no restriction | limiting in particular as a material of the base material 11, Metals, such as a plastics, iron, aluminum, stainless steel, etc. are mentioned. In particular, it is preferable that the substrate is made of plastic because it is lightweight and easy to process a bonded product.
Examples of the plastic include polyesters such as polyethylene terephthalate, polyolefins such as polyethylene, polyimide, polyamide, polyether sulfone, polyphenylene sulfide, polyether ketone, and triacetyl cellulose. Among these, polyethylene terephthalate is preferable.
When the substrate 11 is a light shielding member, examples of the substrate 11 that is a light shielding member include a black polyethylene terephthalate (hereinafter abbreviated as black PET) film, a black iron plate, and the like.

The adhesive member 12 only needs to have adhesiveness capable of bonding the base material 11 and the optical film inspected by the inspection member.
Further, the refractive index of the adhesive member 12 is preferably equal to that of the base 22 of the optical film 20 described later in order to prevent reflection at the interface between the base 22 and the adhesive member 12.

Examples of the material constituting the adhesive member 12 include adhesive materials such as acrylic resin, ethylene-vinyl acetate (EVA) resin, olefin resin, polyester resin, silicone resin, and urethane resin.
In the present invention, it is particularly preferable that the adhesive member has an acrylic resin as a main component. This has a refractive index equivalent to the surface of the optical film to which the adhesive member is bonded (base 22 of the optical film 20 described later), can prevent reflection at the interface with the optical film, and has a higher inspection accuracy. It is for improving.

When the adhesive member 12 is a light-shielding member, examples of the adhesive member 12 that is a light-shielding member include those containing coloring components such as pigments and dyes in addition to the adhesive material described above, and in particular, black coloring Those containing components are preferred.
Furthermore, the coloring component is preferably a black dye. If the adhesive member 12 is an adhesive member colored with a black dye, scattered light on the surface of the optical film can be suppressed, and the inspection accuracy is further improved. If the coloring component for coloring the adhesive member is a pigment such as carbon black, the pigment particles may be reflected by light, which may make it difficult to observe defects such as foreign matters when inspecting the optical film.

  In the present invention, it is most preferable that the adhesive member 12 is colored black by containing an acrylic resin as a main component and containing a black dye. This is because the refractive index inside the adhesive member 12 becomes uniform, and irregular reflection inside can be suppressed.

  The thickness of the adhesive member is preferably 10 μm or more, more preferably 10 to 35 μm, and even more preferably 20 to 30 μm. When the thickness is 10 μm or more, an air layer can be more reliably prevented from being formed between the adhesive member and the optical film, and the inspection accuracy is excellent. The reason is considered that the unevenness due to the solid component in the adhesive member is difficult to be formed. Moreover, the workability | operativity of bonding of an optical film and a test | inspection member is also favorable in the thickness of an adhesive member being 10 micrometers or more.

Next, a method for inspecting the optical film 20 using the inspection member 10 will be described.
The optical film 20 to be inspected by the inspection member 10 of the present invention has a configuration in which a transparent resin layer 21 and a base 22 in contact with the transparent resin layer 21 arranged on the one end 22a side are laminated. The surface on the other end 22 b side of the base 22 is bonded onto the adhesive member 12.

The resin constituting the transparent resin layer 21 is an optically transparent resin, but a non-transparent material can be used as long as it transmits light. In general, the higher the transparency of these resins, the better. The light transmittance (JIS C6714) is preferably 80% or more, more preferably 85% or more. The transparent resin can be inspected even if the resin itself is colored or colored with a dye or pigment if the light transmittance is high.
Examples of these resins include, but are not limited to, resins such as polyester, polyamide, polyvinyl alcohol, polyurethane, polystyrene, polyacetal, polycarbonate, acrylic, epoxy, silicone, cellulose, and various derivatives thereof.
Moreover, in order to obtain high light transmittance, the refractive index of the transparent resin layer 21 is preferably in the range of 1.40 to 1.70.

  In general, a transparent film can be used as the substrate 22. Although non-transparent materials can be used as long as they transmit light, the transparency of these light-transmitting substrates is generally better as they are higher, and the light transmittance (JIS C6714) is 80% or more. More preferably 85% or more, haze value (JIS K7105) of 3.0 or less, more preferably 1.0 or less, most preferably 0.5 or less, and further refractive index of 1.40. Those having ˜1.80 can be preferably used. Specifically, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), triacetyl cellulose (TAC), polyarylate, polyimide, polyether, polycarbonate, polysulfone, polyethersulfone, cellophane, polyamide, polyethylene, polypropylene, polyvinyl Various resin films made of alcohol or the like can be used.

  In the present embodiment, as shown in FIG. 2, an inspection device 30 is used for irradiating the surface of the optical film 20 with light. The inspection device 30 is flat and includes a base 31 on which the optical film 20 can be placed and a light irradiation unit 32 that irradiates the optical film 20 with light. The light irradiation unit 32 is generally a three-wavelength fluorescent lamp, but a tungsten lamp light, a green lamp, a solar lamp, or the like can be used depending on the application.

In the present embodiment, first, the surface of the base 22 of the optical film 20 on the other end 22 b side is bonded onto the adhesive member 12. Thereafter, as shown in FIG. 2, the optical film 20 to which the inspection member 10 is bonded is placed on the base 31 so that the inspection member 10 is positioned on the base 31 side.
And light is irradiated to the surface of the optical film 20 from the light irradiation part 32, and the reflected light from the optical film 20 is visually observed. Next, the quality of the optical film 20 is determined based on the visual appearance of the reflected light and the color.
The present embodiment is not limited to visual observation, and the quality of the optical film 20 may be determined based on a spectral spectrum or the like using a spectrophotometer or the like.

  Further, when it is determined that the substrate 22 is defective by the inspection method, only the substrate 22 before being formed as the optical film 20 is inspected using the inspection member 10 in the same manner as the inspection method, so that the substrate 22 has a defect. It can be confirmed whether or not there is a defect in the transparent resin layer 21.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the inspection member of the present invention, if necessary, a re-peelable protective layer may be further laminated on the adhesive member. Thus, the adhesive member can be protected while the optical film is not inspected (while the optical film is not adhered onto the adhesive member).
As the protective layer, a film having releasability such as polyester, polyethylene, polypropylene, polyethylene terephthalate, or a film obtained by performing a release treatment on the surface of the film (for example, the plastic film described above) is used.

Next, an embodiment that further embodies the present invention will be described.
[Production Example 1]
A low antireflection film (optical film) 20 having the same configuration as the optical film 20 shown in FIG. 1 and including all of streaks, color unevenness, step unevenness, and point defects is produced. The low antireflection film 20 is manufactured using a coating apparatus (not shown).
[Production Example 2]
The inspection member 10 having the same configuration as that of the inspection member 10 shown in FIG.
First, a black dye (product name: Black S-BL, manufactured by Sumika Chemtex Co., Ltd.) is added to an acrylic adhesive for optical use (product name: KP-2254B, manufactured by Nippon Carbide Corporation), and 100 parts by mass of the adhesive solid content. The black adhesive was produced by adding 4.5 mass parts with respect to this, and stirring for 20 minutes with a disper (stirrer).
Then, using the applicator (not shown), the prepared black pressure-sensitive adhesive is applied onto the peeled PET (not shown) so that the thickness after heating becomes 30 μm, and is placed in an 80 ° C. oven (not shown). Charged for 2 minutes. After heating in the oven, black PET 11 was bonded to the black adhesive sheet (adhesive member) 12. After bonding black PET11, peeling PET was peeled and the inspection member 10 was produced.

[Comparative Example 1]
A black cloth (product name: MIYUKITEX M700, manufactured by Miyuki Maori Co., Ltd.) is laid on the base 31, and the low antireflection film 20 is placed thereon, and the surface of the low antireflection film is inspected.
[Comparative Example 2]
Black ink (Magic ink (registered trademark), manufactured by Teranishi Chemical Industry Co., Ltd.) is dropped on the back surface of the low antireflection film 20, and ink is applied with a special brush to prepare an evaluation sample. And the low reflection prevention film 20 is mounted on the base 31, and the surface inspection of the low reflection prevention film 20 is performed.
[Comparative Example 3]
After laminating a polarizing plate (product name: HLC2-5618, manufactured by Sanlitz) so as to be in a crossed Nicol state, the polarizing plate and the low antireflection film 20 are bonded using a laminator. And the low reflection prevention film 20 is mounted on the base 31, and the surface inspection of the low reflection prevention film 20 is performed.

[Example 1]
Using a laminator, the low antireflection film 20 and the inspection member 10 produced in Production Example 2 are bonded together to produce an evaluation sample as shown in FIG. And the low reflection prevention film 20 is mounted on the base 31, and the surface inspection of the low reflection prevention film 20 is performed.

  About each low antireflection film 20 of Comparative Examples 1 to 3 and Example 1, the low antireflection film 20 is made of R (red), G (green), and B (blue) as shown in FIG. Visual observation was performed under a fluorescent lamp containing three wavelengths, and the appearance level of the low antireflection film 20 was evaluated according to the following criteria.

[Evaluation method of streak-like defects (streaks) and point defects]
For the evaluation of streaks and point defects, a 20 cm square antireflection film 20 is prepared, and the number of streaks and point defects that can be measured in 30 seconds by five inspectors is calculated according to the methods of the examples and comparative examples. The average value of the total number was obtained.
In addition, the visibility of streaks and point defects was also evaluated.

[Evaluation method of color unevenness and step unevenness]
Color unevenness refers to a defect that appears as a change in color tone when measured at the above three wavelengths. Step unevenness refers to a defect that appears as contrast when measured at the above three wavelengths. In particular, step unevenness tends to be a defect that appears periodically due to the vibration of the coating apparatus and the influence of air blowing during drying.
For these color unevenness and step unevenness, a 20 cm square low antireflection film 20 was prepared, and the presence or absence of color unevenness and step unevenness was measured by five inspectors using each method of the examples and comparative examples. And evaluated.

  The evaluation results based on the above criteria were as shown in Table 1.

  As is apparent from Table 1, when the inspection methods of Comparative Examples 1 to 3 are used, any of streaks, color unevenness and step unevenness cannot be seen, and the defective product cannot be reliably determined as defective. Is inferior. That is, in the inspection method using the inspection member 10 of the present invention, all of streaks, color unevenness, step unevenness, and point defects can be recognized, so it is possible to accurately determine the quality of the low antireflection film 20. It becomes.

It is sectional drawing which shows an example of the state which adhere | attached the optical film 20 on the inspection member 10 for optical films which concerns on one Embodiment of this invention. It is a schematic diagram which shows the test | inspection method which test | inspects the optical film 20 using the test | inspection member 10 for optical films which concerns on one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Inspection member for optical films, 11 ... Base material, 11a ... One surface of the base material 11, 12 ... Adhesive member, 20 ... Optical film

Claims (11)

  An inspection member for an optical film, comprising: a base material; and an adhesive member laminated on the base material, wherein at least one of the base material and the adhesive member is a light shielding member.   The optical film inspection member according to claim 1, wherein the adhesive member is a light shielding member.   The inspection member for an optical film according to claim 2, wherein the adhesive member contains a coloring component.   The optical film inspection member according to claim 3, wherein the colored component is black.   The optical film inspection member according to claim 4, wherein the coloring component is a black dye.   The inspection member for an optical film according to claim 1, wherein the adhesive member contains an acrylic resin as a main component.   The optical film inspection member according to claim 1, wherein the substrate is made of plastic.   The optical film inspection member according to claim 7, wherein the substrate is made of polyethylene terephthalate.   The optical film inspection member according to claim 1, wherein the base material is a light shielding member.   The optical film inspection member according to claim 1, wherein a protective layer is further laminated on the adhesive member. It is an inspection method of an optical film using the inspection member for optical films according to any one of claims 1 to 10,
Adhering an optical film on the adhesive member;
Irradiating the surface of the optical film with light;
Observing reflected light from the optical film;
And a step of judging the quality of the optical film based on the result of observing the reflected light.

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