JP7212507B2 - UV illuminance evaluation method, UV illuminance evaluation device, and UV irradiation device - Google Patents

Description

The present invention relates to an ultraviolet irradiance evaluation method, an ultraviolet irradiance evaluation apparatus, and an ultraviolet irradiator equipped with this ultraviolet irradiance evaluation apparatus for evaluating the illuminance of ultraviolet rays emitted from an ultraviolet irradiator toward an optical film transported in the longitudinal direction. . In particular, the present invention provides an ultraviolet illuminance evaluation method and an ultraviolet illuminance evaluation apparatus capable of appropriately evaluating whether or not sufficient ultraviolet illuminance is obtained to cure an ultraviolet curable adhesive applied to an optical film. , and an ultraviolet irradiation device.

2. Description of the Related Art Conventionally, optical films have been used in image display devices such as liquid crystal display devices and organic EL display devices. Examples of optical films include polarizing films (polarizers), polarizing plates including polarizing films, retardation films, and antiglare films.
An optical film is usually manufactured using a long belt-shaped raw film. A long belt-shaped optical film as a product is manufactured by successively performing various treatments while transporting the raw film in the longitudinal direction by transport equipment. A long strip-shaped optical film is cut into a size according to the application and used for an image display device or the like.
Hereinafter, in the present specification, the optical film includes not only the optical film as the product, but also the original film and the film of the intermediate product.

For example, in the case of a polarizing film, a protective film may be laminated on one or both sides of the polarizing film. As a method of laminating a protective film on a polarizing film, an ultraviolet curable adhesive is applied to the surface of the protective film in advance, and then the polarizing film and the protective film are laminated by pressing with a laminating roller (nip roller). A method of curing an adhesive by irradiating ultraviolet rays from an irradiation device is known (see, for example, Patent Document 1).
In the method described in Patent Document 1, the UV-curable adhesive is applied to the surface of the protective film in advance. and the polarizing film may be coated with an ultraviolet curable adhesive.

In order to ensure sufficient adhesiveness between the polarizing film and the protective film, it is necessary to maintain the illuminance of the ultraviolet rays to be irradiated at a certain level or higher and to cure the ultraviolet curing adhesive reliably. For this reason, conventionally, the illuminance of ultraviolet rays emitted from an ultraviolet irradiation device is measured and evaluated at appropriate timings, and managed so that the ultraviolet illuminance is above a certain level.

However, the conventional method for evaluating UV illuminance is to place an UV illuminometer in the area irradiated with UV rays from the UV irradiation device, and evaluate the maximum illuminance value (peak illuminance) measured while changing the placement position as appropriate. It was something to do. For this reason, it may not be possible to appropriately evaluate whether or not the ultraviolet illuminance sufficient to cure the ultraviolet curing adhesive is obtained.

JP 2009-134190 A

The present invention has been made to solve the problems of the prior art as described above, and cures an ultraviolet curable adhesive applied to an optical film such as a laminated film of a polarizing film and a protective film. An object of the present invention is to provide an ultraviolet illuminance evaluation method, an ultraviolet illuminance evaluation apparatus, and an ultraviolet irradiation apparatus capable of appropriately evaluating whether or not sufficient ultraviolet illuminance is obtained to obtain a sufficient ultraviolet illuminance.

In order to solve the above-mentioned problems, the present invention provides a method for evaluating the illuminance of ultraviolet rays emitted from an ultraviolet irradiator toward an optical film conveyed in a longitudinal direction, wherein the ultraviolet irradiator serves as ultraviolet light emitting means. , an ultraviolet lamp extending in the width direction of the optical film and having a length equivalent to the width of the optical film, an ultraviolet illuminometer disposed opposite to the ultraviolet irradiation device, and the ultraviolet illuminometer The integrated illuminance of the ultraviolet rays is measured while moving the film in the longitudinal direction, and it is determined whether the integrated illuminance of the ultraviolet rays at positions corresponding to both ends in the width direction of the optical film is a predetermined value or more. If the integrated illuminance of the ultraviolet rays at the positions corresponding to both ends of the direction is equal to or greater than a predetermined value, the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is good, and one of them is less than the predetermined value. In some cases, an ultraviolet illuminance evaluation method is provided for determining that the illuminance of ultraviolet rays emitted from the ultraviolet irradiator is unsatisfactory .

According to the ultraviolet illuminance evaluation method according to the present invention, the ultraviolet illuminance meter arranged opposite to the ultraviolet irradiator is moved in the longitudinal direction of the optical film (transport direction of the optical film) to measure the integrated illuminance. When the optical film is coated with an ultraviolet-curing adhesive, the ultraviolet rays that contribute to curing the ultraviolet-curing adhesive are irradiated on the optical film along the transport direction (longitudinal direction) of the optical film. UV for the whole area. According to the ultraviolet illuminance evaluation method according to the present invention, the integrated illuminance of the entire ultraviolet irradiation region along the transport direction of the optical film, that is, the integrated illuminance of the entire ultraviolet rays that actually contribute to curing the ultraviolet curing adhesive. Since the integrated illuminance that correlates with the amount is measured, it is necessary to appropriately evaluate whether or not the UV illuminance is sufficient to cure the UV-curable adhesive based on the magnitude of this integrated illuminance. can be done.
Further, generally, the illuminance of ultraviolet rays applied to both ends in the width direction of the optical film is often lower than the illuminance of ultraviolet rays applied to the center portion in the width direction of the optical film.
Therefore, when judging whether the illuminance of ultraviolet rays emitted from the ultraviolet irradiator is good or bad, it is necessary to judge whether or not the integrated illuminance of ultraviolet rays at positions corresponding to both ends in the width direction of the optical film is equal to or greater than a predetermined value. (It is not necessary to determine whether or not the integrated illuminance of ultraviolet light at the position corresponding to the central portion in the width direction of the optical film is equal to or greater than a predetermined value).
According to the method for evaluating ultraviolet illuminance according to the present invention, it is not necessary to measure the integrated illuminance of ultraviolet rays at the position corresponding to the central portion in the width direction of the optical film. Reduces time and effort.
In carrying out the method for evaluating ultraviolet illuminance according to the present invention, the ultraviolet illuminometer is placed opposite to the ultraviolet irradiator and moved in a state where there is no optical film in the irradiation area of the ultraviolet ray irradiated from the ultraviolet irradiator. Let it be. However, the present invention is not limited to this, and when there is no space constraint, an ultraviolet illuminometer is placed in front of the optical film (ultraviolet irradiator side) with the optical film in the ultraviolet irradiation area. It is also possible to dispose and move them facing each other.

When the optical film conveyed in the longitudinal direction is irradiated with ultraviolet rays from the ultraviolet irradiator, the optical film is generally conveyed at a preset constant speed in the ultraviolet irradiation region. Therefore, in order to measure the integrated illuminance, which has a strong correlation with the integrated illuminance of the ultraviolet rays actually irradiated during transportation of the optical film, it is preferable to move the ultraviolet illuminometer at a constant speed in the ultraviolet irradiation area.
That is, in the ultraviolet illuminance evaluation method according to the present invention, it is preferable to move the ultraviolet illuminometer at a constant speed in the ultraviolet irradiation region.

According to the preferred method described above, it is possible to measure the integrated illuminance, which has a strong correlation with the integrated illuminance of ultraviolet rays actually irradiated during transportation of the optical film. Appropriately evaluable.

In general, there is often a difference in the illuminance of the irradiated ultraviolet rays between the center portion in the width direction and the both end portions in the width direction of the optical film.
Therefore, in the ultraviolet illuminance evaluation method according to the present invention, it is preferable to measure the integrated illuminance of the ultraviolet rays at the positions corresponding to the center portion in the width direction and both ends in the width direction of the optical film.

According to the preferable method described above, it is possible to appropriately evaluate whether or not a sufficient ultraviolet illuminance is obtained over the entire width direction of the optical film.

In the ultraviolet illuminance evaluation method according to the present invention, it is preferable to move the ultraviolet illuminometer along the transport path of the optical film.

According to the preferred method described above, it is possible to measure the integrated illuminance, which has a strong correlation with the integrated illuminance of the ultraviolet rays actually irradiated during transportation of the optical film, and it is possible to more appropriately determine whether or not the sufficient illuminance of the ultraviolet rays is obtained. can be evaluated to

Further, in order to solve the above problems, the present invention provides an apparatus for evaluating the illuminance of ultraviolet rays emitted from an ultraviolet irradiator toward an optical film conveyed in the longitudinal direction, wherein the ultraviolet irradiator and driving means for moving the ultraviolet illuminometer in the longitudinal direction of the optical film , wherein the ultraviolet irradiator extends in the width direction of the optical film as ultraviolet light emitting means. , an ultraviolet lamp having a length equivalent to the width of the optical film, and the ultraviolet illuminance meter measures the integrated illuminance of the ultraviolet rays while moving in the longitudinal direction of the optical film by the driving means; It is determined whether or not the integrated illuminance of the ultraviolet rays at the positions corresponding to both ends in the width direction of the film is equal to or greater than a predetermined value, and the integrated illuminance of the ultraviolet rays at the positions corresponding to the both ends in the width direction is equal to or greater than the predetermined value. , the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is good, and when either one is less than a predetermined value, the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is poor. , and is also provided as an ultraviolet illuminance evaluation device.

In the ultraviolet illuminance evaluation apparatus according to the present invention, the driving means includes a mounting bar that extends in the width direction of the optical film and on which the ultraviolet illuminometer is mounted, a fixing portion, a moving portion, and the moving portion with respect to the fixing portion. a uniaxial stage having a driving portion that moves a portion in the longitudinal direction of the optical film, and the mounting bar is preferably attached to the moving portion.

According to the above preferable configuration, by moving the moving part in the longitudinal direction of the optical film by the driving part of the uniaxial stage, the mounting bar attached to the moving part also moves in the longitudinal direction of the optical film. If the mounting bar moves in the longitudinal direction of the optical film, the ultraviolet illuminance meter attached to the mounting bar also moves in the longitudinal direction of the optical film. Therefore, the integrated illuminance in the longitudinal direction of the optical film (transporting direction of the optical film) can be measured by the ultraviolet illuminometer.
In addition, since the mounting bar extends in the width direction of the optical film, for example, if the length of the mounting bar is equal to the width of the optical film, there is no need to prepare multiple UV illuminometers. By changing the mounting position, it is possible to measure the cumulative illuminance of ultraviolet rays at positions corresponding to the widthwise central portion and the widthwise both ends of the optical film.

In the preferred configuration described above, the drive section may include a servomotor and a ball screw for converting rotational drive force of the servomotor into linear drive force, and the moving section may be attached to the ball screw. preferable.

According to the above preferable configuration, by driving the servomotor, the rotational driving force of the servomotor is converted into linear driving force by the ball screw, and the moving part attached to the ball screw linearly moves. As a result, the attachment bar attached to the moving part and, in turn, the ultraviolet illuminance meter attached to the attachment bar are also linearly moved. The servomotor can detect the current rotational position and adjust the rotational speed and acceleration/deceleration, so it moves the ultraviolet illuminometer at a constant speed in the ultraviolet irradiation area emitted from the ultraviolet irradiator. is also possible.

Furthermore, in order to solve the above-described problems, the present invention also provides an ultraviolet irradiation device including any one of the ultraviolet irradiance evaluation devices described above and an ultraviolet irradiator.

In the ultraviolet irradiation device according to the present invention, the ultraviolet irradiator includes ultraviolet light emitting means and a reflector that reflects and converges the ultraviolet light emitted by the ultraviolet light emitting means, and the ultraviolet light irradiator and the ultraviolet light Preferably, the distance to the luminometer is adjustable.

According to the above preferable configuration, the ultraviolet light emitted by the ultraviolet light emitting means is reflected by the reflecting mirror and condensed. Since the distance between the UV irradiator and the UV illuminance meter is adjustable, by adjusting the above distance so that the UV light condensing position matches the transport path of the optical film, the optical film can be efficiently exposed to the UV light. can be irradiated.

According to the present invention, it is possible to appropriately evaluate whether or not sufficient UV illumination is obtained to cure the UV-curable adhesive applied to the optical film.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the example of a schematic structure of the manufacturing equipment of the polarizing plate containing a polarizing film which applies the ultraviolet illumination intensity evaluation method which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a front view which shows typically schematic structure of the ultraviolet irradiation apparatus which performs the ultraviolet illumination intensity evaluation method which concerns on one Embodiment of this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is a top view which shows typically schematic structure of the ultraviolet irradiation apparatus which performs the ultraviolet illumination intensity evaluation method which concerns on one Embodiment of this invention. It is a figure explaining the ultraviolet illuminance evaluation method which concerns on one Embodiment of this invention. It is a figure which shows an example of the integrated illuminance of the ultraviolet-ray measured by the ultraviolet illuminance evaluation method which concerns on one Embodiment of this invention, and an example of the peak illuminance of an ultraviolet-ray measured as a reference example.

Hereinafter, an ultraviolet illuminance evaluation method according to an embodiment of the present invention (hereinafter simply referred to as "evaluation method") will be described with reference to the accompanying drawings, taking as an example the case where the optical film is a polarizing film. do.

FIG. 1 is a schematic diagram showing an example of the schematic configuration of a manufacturing facility for a polarizing plate including a polarizing film to which the ultraviolet illuminance evaluation method according to the present embodiment is applied. The arrows shown in FIG. 1 mean the transport direction of each film.
In manufacturing the polarizing plate F using the manufacturing equipment shown in FIG. Then, it is dyed with a dichroic substance such as iodine or a dichroic dye and uniaxially stretched. Then, by drying in an oven 3, a polarizing film F1 is obtained.

Then, one side of the protective film F2 delivered from the delivery roller 5 is coated with an ultraviolet curable adhesive (hereinafter referred to as UV adhesive) by the gravure coater 6 . Then, the bonding roller 7 bonds the protective film F2 coated with the UV adhesive to both surfaces of the polarizing film F1. Next, after curing the UV adhesive with the ultraviolet irradiation device 100 , it is dried in the oven 9 . Finally, a polarizing plate F is obtained by bonding a surface protective film F3 drawn out from a feeding roller 10 to one side of the polarizing film F1 having protective films F2 bonded to both sides thereof by a bonding roller 11. - 特許庁The obtained polarizing plate F is wound up by the winding roller 12 .

In the example shown in FIG. 1, the UV adhesive is applied to the surface of the protective film F2, but the UV adhesive may be applied only to the surface of the polarizing film F1, It is also possible to coat both surfaces with a UV adhesive. In addition, in the example shown in FIG. 1, since the protective film F2 is attached to both sides of the polarizing film F1, two ultraviolet irradiation devices 100 are arranged, but the protective film F2 is attached only to one side of the polarizing film F1. In the case of matching, one ultraviolet irradiation device 100 may be arranged.

The evaluation method according to the present embodiment is performed using the ultraviolet irradiation device 100 among the manufacturing facilities for the polarizing plate F described above.

FIG. 2 is a front view schematically showing a schematic configuration of an ultraviolet irradiation device 100 that executes the evaluation method according to this embodiment. FIG. 2(a) is an overall configuration diagram, and FIG. 2(b) is an enlarged view of a region surrounded by a dashed line B shown in FIG. 2(a). In addition, in FIG. 2A, the insides of the light shielding box 40 and the ultraviolet irradiator 30 are shown in a see-through state. The same applies to FIG. 4(a), which will be described later.
FIG. 3 is a plan view schematically showing the schematic configuration of an ultraviolet irradiation device 100 that executes the evaluation method according to this embodiment. 3, illustration of the servo motor M and the reflecting mirror 33 is omitted.
As shown in FIGS. 2 and 3, the ultraviolet irradiation device 100 according to the present embodiment includes an ultraviolet illuminance evaluation device (hereinafter simply referred to as “evaluation device”) 20, an ultraviolet irradiation device 30, and a light shielding box 40. , is equipped with

The evaluation device 20 emits ultraviolet rays UV emitted from an ultraviolet irradiator 30 toward a polarizing film F1 (not shown in FIGS. 2 and 3) conveyed in the longitudinal direction (vertical direction (Z direction) in this embodiment). It is a device for evaluating the illuminance of In this embodiment, the polarizing film F1 is transported from top to bottom (in the direction of arrow A) along the transport path PL shown in FIG. 2(a). However, when performing the evaluation method according to the present embodiment using the evaluation device 20, the polarizing film F1 is not in the irradiation area of the ultraviolet UV irradiated from the ultraviolet irradiation device 30 (specifically, the light shielding box 40 is not inside).
The evaluation device 20 includes an ultraviolet illuminance meter 21 arranged opposite to the ultraviolet irradiator 30 (in this embodiment, oppositely arranged in the horizontal direction (X direction)), and an ultraviolet illuminance meter 21 arranged in the longitudinal direction (Z direction) of the polarizing film F1. direction).

The type of the ultraviolet illuminometer 21 is not particularly limited as long as it can measure the cumulative illuminance of ultraviolet rays UV (accumulated amount of illuminance of ultraviolet rays UV within the measurement time). As the ultraviolet illuminance meter 21, for example, "PowerPuck II" manufactured by Heraeus can be used.

The driving means 22 includes a mounting bar 221 extending in the width direction (Y direction) of the polarizing film F1 and to which the ultraviolet illuminance meter 21 is mounted, and a uniaxial stage 222 . The ultraviolet illuminance meter 21 is detachably attached to the upper surface of the attachment bar 221 by a known method such as screwing. The uniaxial stage 222 has a fixed portion 222a, a moving portion 222b, and a driving portion 222c that moves the moving portion 222b relative to the fixed portion 222a in the longitudinal direction (Z direction) of the polarizing film F1. The mounting bar 221 is mounted on the moving portion 222b of the uniaxial stage 222 by a known method such as screwing.

The driving unit 222c includes a servomotor M and a ball screw BS that converts the rotational driving force of the servomotor M into a linear driving force. A moving part 222b of the uniaxial stage 222 is attached to a ball screw BS. By driving the servomotor M, the rotational driving force of the servomotor M is converted into a linear driving force by the ball screw BS, and the moving part 222b attached to the ball screw BS moves in the longitudinal direction (Z direction) of the polarizing film F1. It will move in a straight line. As a result, the attachment bar 221 attached to the moving portion 222b and the ultraviolet illuminance meter 21 attached to the attachment bar 221 are also linearly moved in the longitudinal direction (Z direction) of the polarizing film F1.

The ultraviolet irradiator 30 includes a hollow housing 31 , and ultraviolet light emitting means 32 and a reflecting mirror 33 arranged inside the housing 31 .
As the ultraviolet light emitting means 32, the ultraviolet light emitted by the ultraviolet light emitting means 32 extends in the width direction of the polarizing film F1 so that the entire width direction (Y direction) of the polarizing film F1 is irradiated. A UV lamp or the like having an equivalent length is used.
As the reflecting mirror 33, of the ultraviolet rays UV emitted by the ultraviolet light emitting means 32, the ultraviolet rays UV emitted on the opposite side of the polarizing film F1 are reflected to the polarizing film F1 side and condensed. An elliptical cylindrical mirror or the like extending in the (Y direction) is used. When an elliptical cylindrical mirror is used as the reflecting mirror 33, by arranging the ultraviolet light emitting means 32 at one focal point of the elliptical cylindrical surface, the ultraviolet rays UV are condensed toward the other focal point.
The housing 31 of the ultraviolet irradiator 30 is attached to a uniaxial stage (not shown) that moves the housing 31 and the entire ultraviolet irradiator 30 back and forth in the X direction. By driving this uniaxial stage, The distance between the ultraviolet irradiator 30 (ultraviolet light emitting means 32) and the ultraviolet illuminometer 21 is adjustable.

The light shielding box 40 is provided so that the ultraviolet rays UV emitted from the ultraviolet ray irradiator 30 do not damage the polarizing film F1 by irradiating the portion other than the irradiation target portion of the polarizing film F1. The light shielding box 40 is a hollow housing, and an opening 41 is formed in its upper and lower surfaces so as to include the transport path PL of the polarizing film F1 in a plan view. The opening 41 is formed in a rectangular shape having a size through which the polarizing film F1, the ultraviolet illumination meter 21, the mounting bar 221, the fixed portion 222a and the moving portion 222b can pass.
The inside of the light shielding box 40 communicates with the inside of the housing 31 of the ultraviolet irradiation device 30 . Specifically, the right end of the light shielding box 40 and the left end of the housing 31 shown in FIG. is movably fitted to the When adjusting the distance between the ultraviolet irradiator 30 and the ultraviolet illuminance meter 21 by the above-mentioned uniaxial stage (not shown), the ultraviolet irradiator 30 moves in the X direction within the range in which the above-mentioned fitting state is maintained. It will be.

Hereinafter, an evaluation method according to the present embodiment using the evaluation device 20 provided in the ultraviolet irradiation device 100 having the above configuration will be described.
FIG. 4 is a diagram for explaining the evaluation method according to this embodiment. FIG. 4(a) is an overall configuration diagram, and FIG. 4(b) is a diagram showing a change pattern of the moving speed of the ultraviolet illuminometer 21. As shown in FIG.
The evaluation method according to the present embodiment is a method of evaluating the illuminance of ultraviolet rays UV emitted from the ultraviolet irradiator 30 toward the polarizing film F1 conveyed in the longitudinal direction (Z direction). Specifically, in the evaluation method according to the present embodiment, the mounting bar 221 is attached to the uniaxial stage 222 before the polarizing film F1 is transported into the light shielding box 40, such as before the start of manufacturing the polarizing plate F, The ultraviolet illuminance meter 21 is attached to the attachment bar 221 . The mounting position of the ultraviolet illuminance meter 21 on the mounting bar 221 is, for example, as indicated by the solid line in FIG. End.

Next, the uniaxial stage 222 is arranged so as to pass through the upper and lower openings 41 of the light shielding box 40 . At this time, in this embodiment, the arrangement position of the uniaxial stage 222 in the X direction is adjusted so that the ultraviolet illuminance meter 21 can move along the transport path PL of the polarizing film F1. If necessary, the X-direction arrangement position of the ultraviolet illuminance meter 21 may be adjusted by adjusting the X-direction arrangement position of the mounting bar 221 with respect to the uniaxial stage 222 using a spacer or the like. The uniaxial stage 222 after adjustment is fixed to the light shielding box 40 using a predetermined jig (not shown). In addition, if necessary, a uniaxial stage (not shown) that moves the ultraviolet irradiator 30 back and forth in the X direction is driven, and the distance between the ultraviolet irradiator 30 (ultraviolet light emitting means 32) and the ultraviolet illuminance meter 21 is determined by the polarized light. The position of the ultraviolet irradiator 30 may be adjusted so that the distance between the ultraviolet irradiator 30 (ultraviolet light emitting means 32) and the polarizing film F1 when conveying the film F1 is the same. By adjusting the position of the ultraviolet irradiator 30, even if the movement path of the ultraviolet illuminance meter 21 is shifted in the X direction from the transportation path PL of the polarizing film F1, the polarizing film F1 is actually irradiated during transportation. It is possible to measure the integrated illuminance that has a strong correlation with the integrated illuminance of ultraviolet rays UV.

After the above preparations are completed, ultraviolet rays UV are emitted from the ultraviolet irradiator 30 . In this state, the uniaxial stage 222 is driven to move the ultraviolet illuminance meter 21 along the transport path PL of the polarizing film F1 in the longitudinal direction (direction of arrow A) of the polarizing film F1, while measuring the integrated illuminance of the ultraviolet UV. Measure.

The moving speed of the ultraviolet illuminometer 21 can be set by the servo motor M of the uniaxial stage 222 . In this embodiment, the section from the upper opening 41 of the light shielding box 40 to the inside of the light shielding box 40 is defined as the acceleration section, and the section where the ultraviolet light meter 21 is positioned inside the light shielding box 40 is defined as the acceleration section. After the ultraviolet illuminance meter 21 exits from the opening 41 on the lower side of the light shielding box 40, the area up to the position of the ultraviolet illuminance meter 21 indicated by the two-dot chain line in FIG. , the movement speed of the ultraviolet illuminance meter 21 in each section is set by the servo motor M. FIG.

In this embodiment, as shown in FIG. 4B, the ultraviolet illuminometer 21 is moved at a constant speed Vc in the measurement section inside the light shielding box 40, which is the irradiation area of the ultraviolet rays UV. If this constant speed Vc is set to be the same as the transport speed during transport of the polarizing film F1, it is possible to measure the integrated illuminance equivalent to the integrated illuminance of the ultraviolet UV actually irradiated to the polarizing film F1 during transport of the polarizing film F1. be. Velocity Vc is, for example, 5 to 30 m/min, more preferably 5 to 10 m/min. However, it is not always necessary to set the constant speed Vc for moving the ultraviolet illuminance meter 21 to be the same as the transport speed of the polarizing film F1. When the constant speed Vc of the ultraviolet illuminometer 21 is slower than the transportation speed of the polarizing film F1, the integrated illuminance measured by the ultraviolet illuminometer 21 is the same as the measurement time is longer, when the polarizing film F1 is transported. Although the illuminance is larger than the accumulated illuminance of the ultraviolet rays UV actually applied to the polarizing film F1, a value strongly correlated with the actual accumulated illuminance is obtained. Conversely, when the constant speed Vc of the ultraviolet illuminometer 21 is faster than the transport speed of the polarizing film F1, the integrated illuminance measured by the ultraviolet illuminometer 21 is reduced by the amount that the measurement time is shortened. Although the illuminance is smaller than the accumulated illuminance of the ultraviolet rays UV actually irradiated to the polarizing film F1 during the transportation of , a value strongly correlated with the actual accumulated illuminance is still obtained.

In the evaluation method according to the present embodiment, the procedure described above is repeated by changing the mounting position of the ultraviolet illuminance meter 21 on the mounting bar 221 . Specifically, the mounting position of the ultraviolet illuminance meter 21 on the mounting bar 221 is, as indicated by the two-dot chain line in FIG. The other end in the longitudinal direction (the right end in FIG. 3) or the center in the longitudinal direction of the mounting bar 221 corresponding to the center in the width direction of the polarizing film F1 is changed, and the above procedure is repeated. Run. Thereby, the accumulated illuminance of the ultraviolet rays UV can be measured at the positions corresponding to the widthwise central portion and the widthwise both end portions of the polarizing film F1. Then, for example, when all the integrated illuminances of the ultraviolet rays UV at the positions corresponding to the widthwise central portion and the widthwise both ends of the polarizing film F1 are equal to or greater than a predetermined value, the ultraviolet rays emitted from the ultraviolet irradiator 30 If the illuminance of the UV is good and any of the integrated illuminances of the ultraviolet rays UV is less than a predetermined value, it is determined that the illuminance of the ultraviolet rays UV emitted from the ultraviolet irradiator 30 is unsatisfactory. If it is determined to be defective, for example, the cooling means (not shown) for cooling the ultraviolet light emitting means 32 of the ultraviolet irradiator 30 is adjusted, the failure part of the ultraviolet light emitting means 32 is repaired, A countermeasure such as exchanging with a new product may be taken.

In this embodiment, the mounting position of the single ultraviolet illuminance meter 21 is sequentially changed to positions corresponding to the width direction central portion and the width direction both ends of the polarizing film F1, and the integrated illuminance of ultraviolet UV at each mounting position is measured, but the present invention is not limited to this. For example, a plurality of ultraviolet illuminometers 21 corresponding to the number of mounting positions (three in the example of the present embodiment) are prepared, and all of the plurality of ultraviolet illuminometers 21 are mounted on the mounting bar 221 and moved at the same time. It is also possible to simultaneously measure the integrated illuminance of ultraviolet rays UV at a point.

Further, in the present embodiment, the integrated illuminance of ultraviolet UV is measured at positions corresponding to the width direction central portion and width direction both ends of the polarizing film F1, but in general, both width direction ends of the polarizing film F1 are irradiated. The illuminance of the ultraviolet rays UV applied is often smaller than the illuminance of the ultraviolet rays UV applied to the central portion in the width direction of the polarizing film F1. Therefore, it is also possible to adopt a method of measuring only the integrated illuminance of ultraviolet rays UV at positions corresponding to both ends in the width direction of the polarizing film F1 and determining whether or not the integrated illuminance is equal to or greater than a predetermined value. .

Further, in the present embodiment, the integrated illuminance of ultraviolet rays UV is measured while moving the ultraviolet illuminance meter 21 from top to bottom (in the direction of arrow A) in the same manner as in the transport direction of the polarizing film F1. However, the integrated illuminance of ultraviolet rays UV may be measured while moving the ultraviolet illuminance meter 21 in the direction opposite to the transport direction of the polarizing film F1 (from bottom to top). Even if the direction of movement is reversed, the same integrated illuminance can be measured as long as the constant speed Vc is the same.

Furthermore, in the present embodiment, the case where the optical film is the polarizing film F1 has been described as an example, but the present invention is not limited to this, as long as the optical film is irradiated with ultraviolet rays UV, other It is applicable to various optical films.

FIG. 5 is a diagram showing an example of integrated illuminance of ultraviolet rays UV measured by the evaluation method according to the present embodiment and an example of peak illuminance of ultraviolet rays UV measured as a reference example. FIG. 5(a) shows an example of integrated illuminance, and FIG. 5(b) shows an example of peak illuminance.
Specifically, in FIG. 5A, the mounting position of the ultraviolet illuminance meter 21 is sequentially changed to positions corresponding to seven positions in the width direction of the polarizing film F1, and the integrated illuminance of the ultraviolet UV is measured at each mounting position. This is the result of In FIG. 5(b), the mounting positions of the ultraviolet illuminometer 21 are sequentially changed to the same seven positions as in FIG. 5(a), and the ultraviolet illuminometer 21 is moved in the direction of arrow A (see FIG. It is the result of moving and measuring the peak illuminance (maximum illuminance) of ultraviolet UV at each mounting position.
5A and 5B, the horizontal axis of the ultraviolet illuminance meter 21 is based on the position corresponding to the center of the width direction of the polarizing film F1 (the center position of the mounting bar 221 in the longitudinal direction) (0 mm). Means each mounting position. The vertical axes in FIGS. 5(a) and 5(b) mean relative values (set to 1.00) based on the measured value at the position corresponding to the width direction center of the polarizing film F1.

As can be seen by comparing FIG. 5(a) and FIG. 5(b), the integrated illuminance measurement result shown in FIG. 5(a) is higher than the peak illuminance measurement result shown in FIG. 5(b). , the variation in the measurement results (variation in the width direction of the polarizing film F1) is large. The ultraviolet rays UV that contribute to curing the UV adhesive applied to the polarizing film F1 are the ultraviolet rays UV of the entire ultraviolet irradiation area on the polarizing film F1 along the transport direction (Z direction) of the polarizing film F1. According to the evaluation method according to the present embodiment, the integrated illuminance of the entire ultraviolet irradiation area along the transport direction of the polarizing film F1, that is, the integrated amount of the illuminance of the entire ultraviolet UV that actually contributes to curing the UV adhesive. Since the integrated illuminance having a correlation with is measured, it is possible to appropriately evaluate the quality of the illuminance of the ultraviolet ray UV emitted from the ultraviolet ray irradiator 30 . For example, in the result shown in FIG. 5(a), since the integrated illuminance of ultraviolet UV at the positions corresponding to both ends in the width direction of the polarizing film F1 is smaller than the integrated illuminance at the position corresponding to the central part in the width direction, Assume that the illuminance of the ultraviolet rays UV emitted from the ultraviolet ray irradiator 30 should be judged to be defective. Even in such a state that should be determined to be defective, the results shown in FIG. Since it is not much smaller than the peak illuminance at the position corresponding to , there is a risk of erroneously determining that the illuminance of the ultraviolet rays UV emitted from the ultraviolet irradiator 30 is good.

DESCRIPTION OF SYMBOLS 100... Ultraviolet irradiation apparatus 20... Ultraviolet illuminance evaluation apparatus 21... Ultraviolet illuminance meter 22... Driving means 30... Ultraviolet irradiator 32... Ultraviolet light emission means 33... Reflector 40. Light shielding box 41 Opening 221 Mounting bar 222 Single axis stage 222a Fixed part 222b Moving part 222c Driving part BS Ball screw F1 Polarizing film (optical film)
M・・・Servo motor UV・・・Ultraviolet rays

Claims (9)

A method for evaluating the illuminance of ultraviolet rays emitted from an ultraviolet irradiator toward an optical film conveyed in the longitudinal direction,
The ultraviolet irradiator includes an ultraviolet lamp as an ultraviolet light emitting means that extends in the width direction of the optical film and has a length equivalent to the width of the optical film,
An ultraviolet illuminometer is arranged opposite to the ultraviolet irradiator, and the integrated illuminance of the ultraviolet rays is measured while moving the ultraviolet illuminometer in the longitudinal direction of the optical film,
Determining whether the integrated illuminance of the ultraviolet rays at positions corresponding to both ends in the width direction of the optical film is equal to or greater than a predetermined value, and determining whether the integrated illuminance of the ultraviolet rays at the positions corresponding to both ends in the width direction is a predetermined value If it is equal to or more than the value, the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is good, and if either one is less than the predetermined value, the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is bad. is determined to be
UV illuminance evaluation method. moving the ultraviolet illuminometer at a constant speed in the ultraviolet irradiation area;
The ultraviolet illuminance evaluation method according to claim 1. 3. The ultraviolet illuminance evaluation method according to claim 1, wherein the integrated illuminance of the ultraviolet rays is measured at positions corresponding to the widthwise central portion and the widthwise both end portions of the optical film. The ultraviolet illuminance evaluation method according to any one of claims 1 to 3 , wherein the ultraviolet illuminance meter is moved along the transport path of the optical film. A device for evaluating the illuminance of ultraviolet rays emitted from an ultraviolet irradiator toward an optical film conveyed in the longitudinal direction,
An ultraviolet illuminometer arranged opposite to the ultraviolet irradiator;
a driving means for moving the ultraviolet illuminometer in the longitudinal direction of the optical film;
with
The ultraviolet irradiator includes an ultraviolet lamp as an ultraviolet light emitting means that extends in the width direction of the optical film and has a length equivalent to the width of the optical film,
The ultraviolet illuminance meter measures the integrated illuminance of the ultraviolet rays while moving in the longitudinal direction of the optical film by the driving means,
It is determined whether the integrated illuminance of the ultraviolet rays at positions corresponding to both ends in the width direction of the optical film is equal to or greater than a predetermined value, and the integrated illuminance of the ultraviolet rays at the positions corresponding to both ends in the width direction is a predetermined value. If it is equal to or more than the value, the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is good, and if either one is less than the predetermined value, the illuminance of the ultraviolet rays emitted from the ultraviolet irradiator is bad. is determined to be
UV illuminance evaluation device. The drive means
a mounting bar extending in the width direction of the optical film and on which the ultraviolet illuminometer is mounted;
a uniaxial stage having a fixed part, a moving part, and a driving part for moving the moving part with respect to the fixed part in the longitudinal direction of the optical film;
The mounting bar is attached to the moving part,
The ultraviolet illuminance evaluation device according to claim 5 . The drive unit
a servo motor;
a ball screw that converts the rotational driving force of the servomotor into a linear driving force,
The moving part is attached to the ball screw,
The ultraviolet illuminance evaluation device according to claim 6 . The ultraviolet illuminance evaluation device according to any one of claims 5 to 7 ;
and the ultraviolet irradiator,
UV irradiation device. The ultraviolet irradiator is
UV emitting means;
a reflecting mirror that reflects and converges the ultraviolet light emitted by the ultraviolet light emitting means;
The distance between the ultraviolet irradiator and the ultraviolet illuminometer is adjustable,
The ultraviolet irradiation device according to claim 8 .

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