KR102532989B1 - Image display device with fingerprint authentication sensor - Google Patents

Abstract

The present invention provides an image display device having a polarizing plate on the viewing side of a fingerprint authentication sensor, wherein the fingerprint authentication system operates normally even when an orientation film is present on the viewing side of the polarizing plate. can
The present invention is an image display device having a polarizing plate on the viewing side of a fingerprint authentication sensor and an orientation film on the viewing side of the polarizing plate, wherein the angle between the main orientation direction of the orientation film and the extinction axis direction of the polarizer of the polarizing plate is An image display device that is 0 degrees ± 6 degrees or less, or 90 degrees ± 6 degrees or less. (In addition, in the above, “below” applies only to the numerical values following “±”.)

Description

Image display device with fingerprint authentication sensor {IMAGE DISPLAY DEVICE WITH FINGERPRINT AUTHENTICATION SENSOR}

The present invention relates to an image display device having a fingerprint authentication sensor and having an orientation film on the viewing side.

Conventionally, bonding a surface protection film to an image display device for surface protection has been performed. The surface protection film has the purpose of not only preventing damage to the surface but also preventing scattering when an image cell or a surface glass plate is broken, and an orientation film such as biaxially stretched polyester having excellent impact resistance has been used. Moreover, the biaxially stretched polyester film has been used for the image display apparatus also as a scattering prevention film of the member of a touch sensor or a glass member.

On the other hand, in mobile terminals and the like, a face authentication system and a fingerprint authentication system have been adopted in order to ensure a high level of security (Patent Documents 1 and 2).

In such a mobile terminal, in order to achieve a large screen within the size constraints of a mobile, the entire main body is used as a display screen, and a sensor as an authentication system is incorporated in the screen (inside it as an image display area when viewed from the viewer's side). is being proposed Especially in an organic electroluminescence (organic EL) image display device, a fingerprint authentication sensor can be actuated through gaps in pixels of an image display cell, and such a method is spreading.

In an image display device having a fingerprint authentication system in the screen, a polarizing plate is installed on the viewing side of a sensor for authentication. In such an image display device, when an orientation film is present on the viewing side of the polarizing plate, particularly the orientation When a biaxially stretched polyester film was used as the film, there were cases where the fingerprint authentication system did not operate (recognize) or malfunction (false recognition).

Japanese Patent Laid-Open No. 2016-006648 Japanese Patent Publication No. 2018-515820

The present invention is made against the background of these prior art problems. That is, an object of the present invention is to provide an image display device having a fingerprint authentication system and having an orientation film, and in which the fingerprint authentication system operates normally.

As a result of intensive studies to achieve these objects, the present inventors have reached the completion of the present invention. That is, the typical present invention is as follows.

Section 1.

An image display device having a polarizing plate on the viewing side of a fingerprint authentication sensor and an orientation film on the viewing side of the polarizing plate,

An image display device in which an angle formed between a main orientation direction of the orientation film and an extinction axis direction of a polarizer of the polarizing plate is 0 degrees ± 6 degrees or less, or 90 degrees ± 6 degrees or less.

(In addition, in the above, “below” applies only to the numerical values following “±”.)

In an image display device having a polarizing plate on the viewing side of a fingerprint authentication sensor, even when an orientation film is present on the viewing side of the polarizing plate, an image display device in which the fingerprint authentication system operates normally can be provided.

1 is an example in which a fingerprint authentication sensor unit is installed outside a display screen (image display unit).
2 : is an example in which the fingerprint authentication sensor part is installed in the display screen (image display part).
3 is a cross-sectional view of an example in the case where a fingerprint authentication sensor unit is provided in a display screen (image display unit).

(Image display device)

The present invention is an image display device having a polarizing plate on the viewing side of a fingerprint authentication sensor and an orientation film on the viewing side. The fingerprint authentication sensor (fingerprint authentication sensor unit) may be installed outside the display screen or inside the display screen (inside the image display area as viewed from the viewing side). For example, the outside of the display screen referred to here is the state shown in FIG. 1, and the inside of the display screen (inside the image display area as viewed from the viewing side) is the state shown in FIG. The type installed in the display screen is also called a screen embedding type. For example, as shown in Fig. 3, the main body of the fingerprint authentication sensor is installed inside the screen when viewed from the viewer's side. In Fig. 3, an image display cell (eg, an organic EL cell) is arranged on the viewing side of the main body of the fingerprint authentication sensor. A polarizing plate (a circular polarizing plate is preferable when the image display cell is an organic EL cell) is disposed on the viewing side of the image display cell. The orientation film is arrange|positioned through the adhesive layer on the visual recognition side rather than a polarizing plate.

In general, since a polarizing plate is installed in an image display area on an image display cell, an image display device of a type in which a fingerprint authentication sensor is installed within a display screen is subject to the present invention, but a fingerprint authentication sensor is installed outside the display screen Even if it is an image display device of the type in which a polarizing plate is installed in the form of covering a fingerprint authentication sensor, it is a subject of the present invention.

The image display device is preferably a smartphone, mobile PC, PDA, mobile phone, game machine, camera, electronic dictionary or the like.

(Image display cell)

The image display cell used in the image display device of the present invention is not particularly limited, but a liquid crystal display cell and an organic EL (OLED) cell can be cited as preferable examples in that it can be reduced in size and thickness. Among them, the organic EL cell is a preferable example because it can activate the sensor for fingerprint authentication through gaps in the pixels of the cell.

(fingerprint authentication sensor)

The fingerprint authentication sensor may include an optical type, an ultrasonic type, a capacitance type, an electric field strength measurement type, a pressure-sensitive type, a thermal type, and the like, and is not particularly limited, but an optical type or an ultrasonic type is preferable from the compatibility with the configuration of the image display device of the present invention. , in particular, the optical formula is preferred.

As an optical fingerprint authentication sensor, it is marketed under the trade name "Clear ID" by Synaptics, for example.

As an ultrasonic fingerprint recognition sensor, it is marketed under the trade name "Qualcomm Fingerprint Sensors" by Qualcomm Technologies, for example.

(Polarizer)

As described above, the image display device is in a state where the polarizing plate is installed on the viewing side of the fingerprint authentication sensor. A polarizing plate generally includes a polarizer having a function of generating polarized light and a polarizer protective film for protecting the polarizer, but the polarizer protective film may be laminated on only one side of the polarizer, and a polarizer only It can be done. Examples of the polarizer include a thin film in which iodine or an organic dichroic dye is adsorbed to uniaxially oriented polyvinyl alcohol, an alignment film composed of a liquid crystal compound and an organic dichroic dye, and the like, but can be used without particular limitation.

The polarizer protective film is not particularly limited, but unstretched or stretched films such as cellulose-based, polyester-based, cyclic polyolefin-based, acrylic-based, and polycarbonate-based films can be used. However, when it is a stretched film, such as polyester, it is preferable that it is parallel or perpendicular|vertical to the main orientation direction of the extinction axis of a polarizer and a stretched film. Here, "parallel" or "perpendicular" means that the angle formed by the extinction axis of the polarizer and the main orientation direction of the stretched film does not have to be strictly 0 degree or 90 degrees, the allowable width is ±6 degrees, and a more preferable allowable width is ±5 degrees. , a more preferred allowable width is ±4 degrees, a particularly preferred allowable width is ±3 degrees, and a most preferred allowable width is ±2 degrees.

The extinction axis of the polarizer of the polarizing plate may be parallel to the long side of the screen, perpendicular to the long side of the screen, or 45 degrees. This direction is determined according to the type and purpose of the image display cell, and is not particularly limited in the present invention. For example, in the case of an organic EL display cell, it is often arranged at 45 degrees.

A retardation layer may be provided between the polarizer and the image display cell. The retardation layer may be a retardation film obtained by stretching a resin, or an alignment film of a liquid crystal compound obtained by applying and orienting a liquid crystal compound.

In the case of an organic EL cell, a circularly polarizing plate provided with a 1/4 wavelength layer as a retardation layer is used in order to suppress reflection or the like of metal wiring of the cell. The retardation layer of the circular polarizing plate is disposed on the organic EL cell side.

(orientation film)

In the image display device of the present invention, a polarizing plate is provided on the viewer side of the fingerprint authentication sensor, and an orientation film is provided on the viewer side rather than the polarizing plate. The orientation film is located on the surface of the image display device and protects the surface to prevent damage to the image display surface or to prevent glass from scattering when glass members such as image display cells, touch sensors, and surface cover glasses are broken due to impact. It can be used as a film, a transparent conductive film that is also used as an electrode of a touch sensor, a scattering prevention film that is located inside a display device and bonded to a glass member to prevent glass from scattering, but in the present invention, it is used as a surface protection film. It is a preferred form.

In addition, when the film itself is damaged, it is peeled off and it is preferable that a surface protection film is what is newly affixed. It is preferable that the surface protection film is bonded to the image display device with a substrate-less pressure-sensitive adhesive sheet for optics.

Any resin constituting the orientation film is polyester, polyamide, polypropylene, polycarbonate, polystyrene, acrylic resin, cyclic polyolefin, cellulose resin, etc. , polyesters, in particular polyethylene terephthalate.

The oriented film is oriented by stretching and has improved mechanical strength. The oriented film may be a uniaxially oriented film (uniaxially oriented film) or a biaxially oriented film (biaxially oriented film). From a viewpoint of excellent mechanical strength in all directions, it is preferable that it is a biaxially oriented film (biaxially stretched film). On the other hand, from the standpoint of excellent orientation uniformity, a uniaxially stretched film is preferable. When a film is industrially stretched biaxially with a tenter, the main orientation direction is distorted in an arcuate shape in the width direction of the film (bowing phenomenon), but in a uniaxially oriented film uniaxially stretched in the width direction, this distortion is reduced, It is possible to secure a film having a wide range of orientation directions as intended and excellent in orientation uniformity, and bonding or punching processing under the same conditions is possible, which is advantageous in terms of productivity improvement. However, in the perfect uniaxially stretched film, the mechanical strength against the force orthogonal to the orientation direction may be weakened. In this case, in order to increase the mechanical strength in the direction orthogonal to the main orientation direction, weakly stretching is applied also in the direction orthogonal to the main stretching direction (the film obtained in this way is then weakly 2 Also referred to as an axially stretched film or a biaxially oriented film) is also preferable. Although this weak drawing may be performed after main drawing, it is preferable to perform it before main drawing or simultaneously. Of course, complete uniaxial stretching may be sufficient.

In general, for stretching, roll stretching using continuous rolls is used for the flow direction (vertical direction) of the film, and stretching using a tenter is used for simultaneous stretching in the width direction (transverse direction) and horizontally and vertically.

In the present invention, the main orientation direction (main stretching direction) may be a flow direction or a width direction.

Further, here, (modulus of elasticity in the direction orthogonal to the main orientation direction)/(modulus of elasticity in the main orientation direction) is 0.5 or less, or (strength at break in the direction orthogonal to the direction of the main orientation)/(strength at break in the direction of the main orientation) is 0.5 or less, either of which can be referred to as a uniaxially oriented film or an approximately biaxially oriented film.

Stretching may be performed at an appropriate temperature, magnification, and speed according to each raw material. In addition, biaxial stretching and about biaxial stretching can be mainly adjusted by the respective stretching ratios.

Further, in the case of a polyethylene terephthalate film, if the difference (ΔNxy) between the refractive index in the main orientation direction and the refractive index in the direction orthogonal thereto is 0.055 or more, preferably 0.06 or more, it can be said to be a substantially biaxially stretched film. Further, when the refractive index of the slow axis is 1.68 or more, preferably 1.685 or more, and ΔNxy is 0.095 or less, preferably 0.093 or less, it can be said that weak biaxial stretching is applied.

In addition, as described above, in order to ensure mechanical strength from each direction, a biaxially oriented film (biaxially stretched film) is preferable, and ΔNxy is preferably less than 0.06, more preferably less than 0.055, but homogeneous and uniform Not only is it difficult to achieve biaxial orientation, but the orientation direction easily changes among films of the same production due to slight fluctuations in manufacturing conditions. In view of manufacturing, in order to achieve a uniform orientation direction over a large area of the film, ΔNxy is preferably 0.01 or more, more preferably 0.015 or more, and particularly preferably 0.02 or more.

Further, in order to enhance uniaxiality and stabilize the orientation direction in the entire width of the film, ΔNxy is preferably 0.065 or more, more preferably 0.070 or more, even more preferably 0.075 or more, particularly preferably 0.080 or more, and most preferably 0.080 or more. Preferably it is 0.085 or more. ΔNxy is preferably 0.16 or less, more preferably 0.15 or less, particularly preferably 0.14 or less, and most preferably 0.13 or less. When it exceeds the above, it becomes easy to tear too much and the function at the time of using as a surface protection film may become unable to be maintained.

The manufacturing method of the orientation film is not particularly limited. For example, taking the case of a polyethylene terephthalate film as an orientation film, it can manufacture with the following method.

Generally, stretching is performed with a continuous roll in the vertical direction (film flow direction) as the first stretching, and then in the width direction (direction orthogonal to the film flow direction) as the second stretching, Both ends of the width of the film are held with clips and drawn in a tenter. In addition, the first stretching method and the second stretching method may be reversed. The first draw ratio is preferably 1.0 to 3.5 times, particularly preferably 1.0 to 3.0 times. The second draw ratio is preferably 2.5 to 6.0 times, particularly preferably 3.0 to 5.5 times. In addition, in the case of only uniaxial stretching, it is preferable to employ the second stretching ratio as the stretching ratio. In any stretching, the stretching temperature is preferably 80 to 130°C, particularly preferably 90 to 120°C. Alternatively, both ends of the width of the unstretched film may be held with clips, and biaxial stretching may be performed simultaneously in the longitudinal direction and the width direction. Subsequently, it is preferable to heat-treat preferably at 100 to 250°C, more preferably at 180 to 245°C. In addition, although the above tenter stretching was performed in the width direction, stretching may be performed in an oblique direction with respect to the machine direction.

(Angle between extinction axis (absorption axis) of polarizer and main orientation direction of orientation film)

In the present invention, the extinction axis (absorption axis) of the polarizer and the main orientation direction (direction parallel to the main orientation axis) of the oriented film are preferably parallel or perpendicular. Here, parallel or perpendicular means that the angle formed by the extinction axis of the polarizer and the main orientation direction of the orientation film does not have to be strictly 0 degrees or 90 degrees, and is preferably 0 degrees ± 6 degrees or less or 90 degrees ± 6 degrees or less. , 0 degrees ± 5 degrees or less or 90 degrees ± 5 degrees or less is more preferable, 0 degrees ± 4 degrees or less or 90 degrees ± 4 degrees or less is more preferable, 0 degrees ± 3 degrees or less or 90 degrees ± 3 degrees or less is particularly preferred, and 0 degrees ± 2 degrees or less or 90 degrees ± 2 degrees or less is particularly preferred. In addition, the term "less than or equal to" means that only the numerical value next to "±" is applied. Therefore, for example, the above "0 degrees ± 6 degrees or less" means that fluctuations in the range of 6 degrees above and below 0 degrees are allowed. Similarly, "90 degrees ± 6 degrees or less" means that fluctuations in the range of 6 degrees above and below 90 degrees are allowed.

When a plurality of oriented films exist, it is preferable that all the oriented films have the above relationship.

If the angle between the extinction axis of the polarizer and the main alignment direction of the alignment film is out of a preferred range, there may be a problem that the sensor does not operate or malfunction occurs. This is because the optical fingerprint sensor irradiates light from the bottom toward the surface of the display device and reads the fingerprint with the reflected light. Because it advances in the orientation film with , it becomes elliptically polarized light because it is reflected and passes through the polarizer again, it is affected by the orientation film with retardation, and it is a specific wavelength in the image of the sensor. It is considered that this is because the light quantity is reduced in the area, and it becomes difficult to detect an accurate pattern of a fingerprint when the sensor's light-receiving wavelength is fixed. In addition, it is considered that even when the sensor receives light in a wide wavelength range, the total amount of light decreases, making it impossible to maintain the accuracy of the sensor and subsequent processing. Further, these reasons are not beyond the realm of speculation and do not limit the present technology.

In addition, as for the main orientation direction, the slow axis and the fast axis are measured with a molecular orientation meter (for example, MOA-6004 type molecular orientation meter manufactured by Oji Scientific Instruments Co., Ltd.), and the slow axis is taken as the main orientation axis. In addition, things with a negative photoelastic coefficient, such as a styrenic resin, make the fast axis the main orientation direction.

Although the thickness of an orientation film can be set suitably according to each objective, it is preferable that it is 5-200 micrometers. It is more preferably 10 to 150 μm, particularly preferably 20 to 100 μm. When it is less than 5 micrometers, not only it may be too thin and handling may be bad, but also when using it as a surface protection film etc., sufficient mechanical strength suitable for the purpose may not be ensured. When it exceeds 200 micrometers, not only rigidity may become too high and handleability may deteriorate, but also may not be suitable for thinning of the display device.

The in-plane retardation of the oriented film is not particularly limited as long as it is more than the level at which a clear state is observed as the orientation direction of the molecules, but it is preferably 1000 nm or more. In addition, smartphones and the like are often operated outdoors while wearing polarized sunglasses, and when viewed from an oblique direction when wearing polarized sunglasses, coloring or rainbow spots may occur. In order to reduce the iridescence which arises when viewing an image display apparatus from an oblique direction, it is preferable that the in-plane retardation of an orientation film is 3000 nm or more. More preferably, it is 4500 nm or more, and particularly preferably 6000 nm or more. Further, the in-plane retardation is preferably 30000 nm or less, more preferably 10000 nm or less, still more preferably 9000 nm or less. Even if the in-plane retardation exceeds 30000 nm, it is difficult to expect a significant improvement in the iridescence-reducing effect, and thickness is required. Strength may decrease.

(Excluding surface processing)

The oriented film may be surface processed according to each purpose. For example, if it is a surface protection film, it is a hard coat, an antireflection coat, a low reflection coat, an antistatic coat, etc. Moreover, you may provide an easily adhesive coat.

When a fingerprint is applied to the surface of the orientation film and the reflection is detected, the visual side of the surface protection film is preferably smooth enough to recognize a fingerprint. The surface roughness SRa of the surface on the visual side is preferably 100 nm or less, more preferably 50 nm or less, and particularly preferably 30 nm or less.

The total light transmittance of the orientation film is preferably 80% or more, more preferably 85% or more, and particularly preferably 88% or more. Moreover, it is preferable that the haze of an orientation film is 3 % or less, More preferably, it is 2.5 % or less, Especially preferably, it is 2 % or less.

Example

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(1) breaking strength

It was measured according to JIS C-2318.

(2) modulus of elasticity

It was measured according to JIS C-2318.

(3) Retardation, ΔNxy

Retardation is a parameter defined by the product (ΔNxy×d) of the anisotropy (ΔNxy=|nx-ny|) of the refractive index of two orthogonal axes on a film and the film thickness d (nm) (ΔNxy×d), which represents optical isotropy and anisotropy is a measure The biaxial refractive index anisotropy (ΔNxy) was obtained by the following method. Using a molecular orientation meter (MOA-6004 type molecular orientation meter manufactured by Oji Keisoku Instruments Co., Ltd.), the direction of the slow axis of the film is determined, and the direction of the slow axis is parallel to the long side of the sample for measurement. A rectangle was cut out and it was set as the sample for a measurement. For this sample, the refractive index of two orthogonal axes (refractive index in the slow axis direction: nx, in-plane refractive index in the direction orthogonal to the slow axis direction (ie, refractive index in the fast axis direction): ny), and refractive index in the thickness direction (nz) was obtained with an Abbe refractometer (manufactured by Atago, NAR-4T, measurement wavelength 589 nm), and the absolute value (|nx-ny|) of the biaxial refractive index difference was defined as the refractive index anisotropy (ΔNxy). The thickness d (nm) of the film was measured using an electric micrometer (Millitron 1245D, manufactured by Fine Lupe Co., Ltd.), and the unit was converted into nm. The retardation (Re) was obtained from the product (ΔNxy×d) of the anisotropy of the refractive index (ΔNxy) and the thickness d (nm) of the film.

(4) extinction axis of polarizer

The surface protection film or the like is peeled off, and an image display device with linearly polarized light emitted is turned on, and a polarizing filter with a known extinction axis is placed on top of it, and the direction of the extinction axis of the polarization filter in the darkest state is determined. The direction at 90 degrees was set as the direction of the extinction axis.

(5) Main orientation direction

It was measured with a molecular orientation meter (MOA-6004 type molecular orientation meter manufactured by Oji Keisoku Instruments Co., Ltd.).

(6) light transmittance

It was measured according to JIS K-7105.

(7) Haze

It was measured according to JIS K-7105.

(8) Three-dimensional central plane average surface roughness (SRa):

A film with an area of 50 mm × 50 mm is cut out, and using a three-dimensional surface shape measurement device (manufactured by Ryoka System, Micro Map 550N (measurement conditions: wave mode, measurement wavelength 560 nm, objective lens 10x)) perpendicular to the film plane It was measured from the direction, and a CCD camera image capture area of 400 μm × 400 μm was designated, and SRa given by the following equation was obtained. On both sides of the film, the number of measurements was set to 16, respectively, and their average value was obtained. In addition, fractions after the decimal point were rounded off by rounding off.

[Equation 1]

Here, S _M = Lx×Ly, Lx and Ly are ranges in the x and y directions, and f(x, y) is the height of the measurement points (x, y) from the average plane.

(9) Number of authentication successes

10 activations by fingerprint authentication were attempted, and the number of activations was expressed as the number of times. In addition, after wiping off the fingertips with a wet towel, water was removed with a dry towel, and the fingertips were placed on the sensor part after about 3 seconds.

(10) Surface protection properties

Using the adhesive for optics, the orientation film was affixed on the surface protection glass for a commercially available smartphone, and the test sample was created. The sample was placed on a stand (the film surface was on top) through a spacer having a thickness of 5 mm at each side of the sample, and a steel ball was dropped from above. Tested on 5 samples. In addition, when the glass was not broken, the steel ball was dropped again.

○: The glass was broken, but there was no sample in which the film was torn.

(triangle|delta): There existed a sample in which tearing of the film was recognized slightly at the impact part of the steel ball.

x: There was a sample in which the film was greatly torn.

(11) Observation of rainbow stains

An image display device for a fingerprint authentication test was observed from an oblique direction while wearing polarized sunglasses.

○: No rainbow spots were observed.

(triangle|delta): Weak rainbow stain was recognized.

x: Clear rainbow stains were observed.

(Preparation of orientation film)

The following orientation films A, B and C were prepared. Each characteristic is shown in Table 1.

Oriented Film A:

A film with a film thickness of 75 μm of Cosmo Shine (registered trademark) A4300 manufactured by Toyobo Co., Ltd. was used. In addition, since the main orientation direction differs depending on the slit position of the film roll, a portion having a main orientation direction of 90 degrees ± 6 degrees or less with respect to the longitudinal direction of the film roll was cut out and used.

Oriented Film B:

Polyethylene terephthalate chips containing 0.7% by mass of porous silica with an average particle diameter of 0.9 μm (intrinsic viscosity 0.60 dl/g (phenol: 1,1,2,2-tetrachloroethane = 6:4 dissolved in a mixed solvent and heated at 30 ° C.) Measurement), hereafter abbreviated as PET) was dried, melted at 280° C. by a melt extruder, and extruded into a sheet form on a cooling roll to obtain an unstretched polyethylene terephthalate sheet. Next, a coating agent for an easily bonding layer comprising a water-dispersible polyester resin and a block isocyanate-modified polyurethane water dispersion is applied to one side of the unstretched sheet, and then guided to a tenter-type simultaneous biaxial stretching machine, While holding the ends with clips, they were guided to a hot air zone at a temperature of 125°C, and stretched 1.8 times in the longitudinal direction and 4 times in the width direction. While maintaining the state, it was processed at a temperature of 225°C for 10 seconds, and further, a 2.5% relaxation treatment was performed in each of the vertical and horizontal directions. Since the production film roll showed slight distortion of orientation due to bowing at the end position, a portion where the main orientation direction was 90 degrees ± 6 degrees or less with respect to the longitudinal direction of the film roll was cut out and used.

Oriented Film C:

Toyobo Co., Ltd. Cosmo Shine (registered trademark) super-birefringent type (SRF) film with a thickness of 80 μm was used. In addition, since the main orientation direction is substantially stable in the width direction of the film roll, it was arbitrarily selected, and it was confirmed that the main orientation direction was 90 degrees ± 6 degrees or less with respect to the longitudinal direction of the film roll.

[Table 1]

(Creation of orientation film in which hard coat layer and pressure-sensitive adhesive layer are laminated)

A UV curable hard coating agent was applied to the easily adhesive coating surfaces of the orientation films A, B, and C, and after drying, ultraviolet rays were irradiated with a high-pressure mercury lamp to obtain orientation films A, B, and C having a hard coat layer on one side. . Further, a commercially available optical pressure-sensitive adhesive (substrate-less type) was laminated on the surface opposite to the surface on which the hard coat layer was laminated on each orientation film by roll-to-roll after peeling off the easy-release sheet. Table 2 shows the measurement results of the three-dimensional center plane average surface roughness SRa on the hard coat layer side for each orientation film.

[Table 2]

(Assembly of Image Display Device with Surface Protection Film)

Examples 1 to 15, Comparative Examples 1 and 2

The orientation film on which the above hard coat layer and the pressure-sensitive adhesive layer were laminated was cut to the size of the entire screen of X20 Plus UD manufactured by VIVO, an organic EL display device having an optical fingerprint authentication sensor built into the display screen. This was made into a surface protection film, and it was affixed on the screen of the said organic electroluminescent display device through the adhesive surface. In addition, the surface protection film affixed at the time of purchase was peeled off. The angle at the time of bonding and the evaluation result were shown to Tables 3-5. The angle was confirmed on the orientation film on which each cut hard coat layer and the pressure-sensitive adhesive layer were laminated, and then bonded.

Example 16

Imitating the case where a transparent conductive film of a polyester film is used as a touch sensor, orientation films A and C in which a hard coat layer and an adhesive layer are laminated are laminated and bonded in the same manner as above.

[Table 3]

[Table 4]

[Table 5]

In Tables 3 to 5, positive numbers indicate a right-hand rotation direction, and negative numbers indicate a left-hand rotation direction when the main orientation axis is viewed from the viewing side with respect to the light transmission axis of the polarizer.

1: image display device 2: image display unit
3: fingerprint authentication sensor unit 21: image display cell
22: polarizing plate 23: adhesive layer
24: orientation film (surface protection film) 31: fingerprint authentication sensor body

Claims (3)

An image display device having a polarizing plate on the viewing side of a sensor of an authentication system and an orientation film on the viewing side of the polarizing plate,
The angle formed between the main orientation direction of the orientation film and the extinction axis direction of the polarizer of the polarizing plate is 0 degrees ± 6 degrees or less, or 90 degrees ± 6 degrees or less,
The polarizing plate is an image display device comprising a polarizer and a polarizer protective film.
(In addition, in the above, “below” applies only to the numerical values following “±”.) According to claim 1,
An image display device in which an authentication system irradiates light from the bottom toward the surface of the display device and reads the reflected light with a sensor. According to claim 1 or 2,
The image display device according to claim 1 , wherein the orientation film is bonded to an image display device with a substrate-less pressure-sensitive adhesive sheet for optics so that it can be peeled off and reapplied, and the image display device includes an organic EL cell.

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