KR102185732B1 - Protection film for uniformalizing luminance of diplay device and diaplay device having the same - Google Patents

Abstract

The present invention relates to a protection film for a display device. The film protects a lower portion of a display panel and comprises a base film and an adhesive layer on the base film. The film has a transmittance of 30-85% in a wavelength range of 400-760 nm, a total reflection rate (A) of less than 55% in the wavelength range of 400-760 nm, and a diffused reflection rate (B) of less than 1%. The film has low light reflectivity and low light transmissivity.

Description

Protection film for uniformalizing luminance of a display device, and display device including the same {Protection film for uniformalizing luminance of diplay device and diaplay device having the same}

The present invention is located under the display panel, and relates to a protective film for improving the luminance non-uniformity of the front surface of the display resulting from external light received from the top and reflected light of a light source emitted from the device. In more detail, the difference in transmittance, light absorption, refractive index, reflectance, and electric charge resulting from the difference in the material constituting the layer/film located at the bottom of the panel with transparency and the discontinuity of the material due to the pattern of the layer/film. It relates to a protective film for improving the luminance non-uniformity of the front surface of the display due to the imbalance.

In recent years, with the rapid development of information communication technology and the expansion of the market, flat panel displays are in the spotlight as display devices. Such a flat panel display device is a liquid crystal display device. Typical examples include plasma display panels, organic light emitting diodes, quantum dot light emitting diodes, and micro light emitting diodes.

Organic light-emitting devices have advantages such as fast response speed, light, thin and short, low power consumption, self-luminous devices, and flexibility, and thus demand for next-generation display devices, flexible displays as well as lighting is increasing.

The organic light emitting device is formed by depositing a transparent electrode, a hole injection layer, a hole transport layer, an organic light emitting layer, an electron transport layer, an electron injection layer, and a metal electrode in the order of a glass substrate, and electrons and holes supplied from both electrodes are recombined in the organic light emitting layer. It is the principle of emitting light using the emitted energy.

Fingerprint recognition technology is widely used for user authentication in smartphones or payment means, and for this purpose, a fingerprint recognition sensor has been manufactured by combining a fingerprint recognition sensor with an organic light emitting device having a transparent characteristic.

Accordingly, the organic light emitting device includes an organic light emitting diode display panel; And a fingerprint sensor package provided under the organic light emitting diode display panel.

The fingerprint recognition sensor is electrically connected to the organic light emitting diode display panel, and when light reflected from the fingerprint in contact with the cover glass penetrates the display panel and reaches the fingerprint recognition sensor disposed under the organic light emitting diode display panel, As a rain, the fingerprint is recognized. However, in order to absorb external light and various scattered light from the top, the functional film located on the fingerprint recognition sensor absorbs and blocks most of the light including a dye or pigment of a color that absorbs black or scattered light. Therefore, in order for the light reflected on the fingerprint to at least reach the front fingerprint sensor, a hole must be formed in a partial area of the functional film by perforating a functional film corresponding to a portion for recognizing the reflected light of the fingerprint.

However, if there is a different material or air gap between the protective film under the panel and the fingerprint sensor between the fingerprint sensor and the functional film, the part where the different medium and the fingerprint sensor exist and the functionality of the main surface There is a problem in that a difference in transmittance, light absorption, reflectance, and refractive index occurs between portions where the film is present, and the difference in light scattering by it is visually recognized by the user. In addition, if there is an air gap, it is possible to remove static electricity, or due to the non-continuity of the material between the sensor attachment portion and the functional film attachment portion. do. Therefore, in order to solve this problem, there is a need for a protective film that minimizes the amount of reflected light to the front of the display and quickly resolves the imbalance of electric charges to improve visibility.

The present invention has been conceived to solve the above-described problems, and an object of the present invention is to provide a protective film under a display panel having a low light reflectance and high light absorption, and a specific transmittance range, and a display panel and a display device to which the same.

The present invention introduces the light reflection reduction property in the protective film, and the display front surface caused by the difference in materials constituting the layer/film located under the panel having transparency and the discontinuity of the material due to the pattern of the layer/film The purpose of this is to improve the luminance imbalance of and to prevent a decrease in the fingerprint recognition rate between the fingerprint sensor and the display panel.

Since the protective film according to the present invention has a high reflectance reduction effect at low cost, when applied to the lower panel of the display, it significantly reduces the amount of light reflected to the front of the display, thereby improving the luminance imbalance in the front of the display and Visibility can be improved.

In addition, in various display devices including a fingerprint sensor, there is provided a display panel that increases a fingerprint recognition rate and has good visibility regardless of a pattern of a functional film included in a lower panel of the display and the presence or absence of a fingerprint sensor.

1 is a cross-sectional view of a display according to a conventional display device and a screen defect due to discontinuity of a functional film.
2 is a cross-sectional view of a display device to which a protective film is applied according to an embodiment of the present invention.
3 to 5 are cross-sectional views of a protective film according to an embodiment of the present invention.
6 shows a final finished product of the protective film according to an embodiment of the present invention.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims. Accordingly, in some embodiments, well-known process steps, well-known device structures, and well-known techniques have not been described in detail in order to avoid obscuring interpretation of the present invention. The same reference numerals refer to the same components throughout the specification.

Spatially relative terms "below", "beneath", "lower", "above", "upper", etc., as shown in the figure It may be used to easily describe the correlation between the device or components and other devices or components. Spatially relative terms should be understood as terms including different directions of the device during use or operation in addition to the directions shown in the drawings. For example, if an element shown in the figure is turned over, an element described as “below” or “beneath” of another element may be placed “above” another element. Accordingly, the exemplary term “below” may include both directions below and above. The device may be oriented in other directions, and thus spatially relative terms may be interpreted according to the orientation.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification, "comprises" and/or "comprising" refers to the presence of one or more other components, steps, actions and/or elements, and/or elements, steps, actions and/or elements mentioned. Or does not exclude additions.

In the present invention, “opening” means a hole formed in an arbitrary layer. The "opening" forms a "air gap" made of an air layer or is filled with a material different from the layer in which the hole is formed, thereby forming a "pattern part" by discontinuous coating of the layer. Therefore, unless otherwise specified, in the present invention, "pattern part" means a pattern formed in an arbitrary layer, and may be used in the same meaning as "opening part", "air gap" or "pattern".

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

1 is a cross-sectional view of a display device as an embodiment of a conventional display device.

In FIG. 1A, a fingerprint sensor 100 is located on a display upper panel 500 including pixels and a lower side of the PI substrate 400 of the panel, and a functional film 200 having an opening 210 on the fingerprint sensor 100 This is located, and a protective film including a base film 310 and an adhesive layer 320 is positioned on the functional film 200.

The functional film 200 of the display device is a film having a function required and driving a panel, such as a heat dissipation function, impact resistance, and light blocking performance, and its characteristics are not limited, and is located on the fingerprint sensor 100, and the fingerprint sensor ( It has an opening 210 in a portion corresponding to a region of 100). The opening serves to expose the optical 　 fingerprint 　 sensor 100 and sense the light reflected from the finger by being radiated from the display 　 upper panel 500. An air gap may be formed in the region of the opening 210 formed due to discontinuity of the functional film 200, or another material different from the functional film 200 may fill the region of the opening 210. In the latter case, the functional film 200 has a region in which the opening 210 is present and a region not present, and thus has different optical characteristics.

As shown in FIG. 1A, when light is incident toward the protective film 300, the first reflection occurs from the pressure-sensitive adhesive layer 320, the second reflection occurs from the base film 310, and the functional film 200 The third reflection occurs, and finally, the light that has passed through the opening 210 arrives at the front surface of the fingerprint sensor 100, so that the last reflection occurs. Therefore, when viewed from the front of the protective film 300, it can be seen that the reflectance of light is particularly high in the area where the sensor in the area of the opening 210 is present, which means that the reflectance and transmittance of light from the rear of the display panel are ), which causes poor visibility by the user. In addition, an imbalance of electric charge occurs according to the pattern area of the functional film 200 attached to the panel, so that a poor visibility due to a difference in electrostatic properties occurs even in the flow of a fine current (see FIG. 1B ).

The present invention solves this problem by imparting visibility to the protective film 300 positioned on the functional film 200 in order to eliminate the external light reflection and electric charge imbalance occurring at the rear surface of the display panel.

According to an embodiment of the present invention, the protective film under the display panel of the present invention includes a base film; And a pressure-sensitive adhesive layer on the base film, and has a transmittance of 30 to 85% in a wavelength range of 400 to 760 nm, a total reflectance (A) of less than 55% in a wavelength range of 400 to 760 nm, and a diffuse reflectance (B) of 1 It provides a protective film under the display panel of less than %.

The protective film is a translucent or transparent film and has a transmittance of 30 to 85%. It is preferably 35 to 85%, more preferably 40 to 85%. The protective film satisfies the transmittance in the above range, thereby absorbing light reflected from the lower layer of the display panel as much as possible so that the difference of the lower materials and the presence or absence of a pattern cannot be recognized on the front surface of the display. If the transmittance of the protective film is less than 30%, the optical transmittance is low, so that fingerprints in contact with the upper part of the panel cannot be properly recognized, which may result in deterioration of the fingerprint recognition function. Due to the low transmittance, there is a possibility of defective sample shipment due to a problem in the inspection, and when the transmittance of the protective film exceeds 85%, most of the light reflected from the pattern passes through the front of the display and is recognized by the user, causing poor visibility. .

The protective film preferably has a total reflectance (A) of less than 55% and a diffuse reflectance (B) of less than 1% in a wavelength range of 400 to 760 nm. At this time, the method of measuring the total reflectance (A) and the diffuse reflectance (B) is an aluminum reflector showing a value of 55 to 65% and diffuse reflectance <1% at a wavelength of 500 nm using a Konica Minolta CM-2600D device. Based on, after placing the protective film on the reflective plate, the reflectance measured from the surface of the protective film was measured.

In one embodiment of the present invention, the pressure-sensitive adhesive layer (1) has a low surface resistance, (2) has excellent antistatic performance, (3) has a low total reflectance and diffuse reflectance, (4) has a specific range of optical transmittance. It is required to have.

According to an embodiment of the present invention, the pressure-sensitive adhesive layer has a surface resistance of less than 1×10 ¹³ Ω/sq, and more preferably less than 1×10 ¹² Ω/sq. The surface resistance was measured in accordance with JIS-K-6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analysis Tech, Hyresta UP MCP-HT450 type) in an atmosphere of a temperature of 23°C and a humidity of 50% RH.

According to one embodiment of the present invention, the pressure-sensitive adhesive layer 320 may include an antistatic agent. Examples of the antistatic agent include (a) various cationic antistatic agents having cationic groups such as quaternary ammonium salts, pyridinium salts, and first to tertiary amino groups, (b) sulfonate groups, sulfate ester bases, phosphate ester bases, and phosphonates. Anionic antistatic agents having anionic groups such as fonate groups, (c) positive antistatic agents such as amino acid and amino sulfuric acid esters, (d) nonionic antistatic agents such as amino alcohol, glycerin, and polyethylene glycol, ( e) a high molecular weight antistatic agent obtained by making the above antistatic agent high molecular weight, and the like, but is not limited thereto. In a preferred embodiment, the present invention may include a polymer-type antistatic agent. The polymeric antistatic agent is basically composed of ethylenically unsaturated carboxylic acid, and is dispersed and immobilized in a resin during molding to capture electric charges and then move inside the resin to suppress the generation of static electricity. Therefore, antistatic properties last a long time, there is little change in physical properties, and the change in surface properties is not severe.

As non-limiting examples of the ethylenically unsaturated carboxylic acid, ethylene acrylic acid copolymer, ethylene methacrylic acid copolymer, ethylene chloroacrylic acid copolymer, ethylene crotonic acid copolymer, ethylene itaconic acid copolymer, ethylene maleic acid copolymer, Ethylene fumaric acid copolymer, ethylene citonic acid copolymer, ethylene mesaconic acid copolymer, and the like.

According to one embodiment of the present invention, the pressure-sensitive adhesive layer 320 may include a light-absorbing colorant, for example, impurities such as pigments and dyes. The pressure-sensitive adhesive layer 320 includes impurities such as pigments and dyes, thereby minimizing the reflection of light itself, but from a lower layer such as the base film 310, the functional film 200, the fingerprint sensor 100, etc. The reflected light can be absorbed to increase visibility of the display device.

The pressure-sensitive adhesive layer 320 measures reflectance and transmittance so that the sum of them is minimized, and has high light absorbance, so that the transmittance of the protective film 300 of the present invention ultimately becomes 30 to 85%, and 400 It contributes so that the total reflectance (A) is less than 55% and the diffuse reflectance (B) is less than 1% in the wavelength range of ~ 760 nm. The pigments and dyes included in the pressure-sensitive adhesive layer 320 may be used without limitation as long as they are light absorbing materials.

As long as the transmittance and reflectance are satisfied, the composition of the pressure-sensitive adhesive layer 320 is not limited, and for example, it may be prepared from an adhesive composition containing an acrylate-based copolymer, and the adhesive composition is a 　acrylate-based 　 compound, a photocuring agent, and It may contain a photoinitiator.

According to an embodiment of the present invention, between the base film 310 and the pressure-sensitive adhesive layer 320; And/or one or more conductive layers 10 may be included on the rear surface of the base film 310 (FIG. 3). The conductive layer 10 prevents a decrease in visibility due to an imbalance in charge density under the display due to the presence of the pattern portion 210. The conductive layer 10 may include Indium Tin Oxide (ITO) or Fluorine-doped Tin Oxide (FTO). In addition, the conductive layer 10 is Cu, Cu alloy, Ag, Ag alloy, Ni+Cr, Ni+Ni alloy, Mo/Ag, Mo/Al/Mo, Ni+Cr/Cu/Ni+Cr, Ni alloy/ Conductive materials such as Cu, Ni alloy/Cu/Ni alloy, Mo/APC, Cu/Ni+Cu+Ti, Ni+Cu+Ti/Cu/Ni+Cu+Ti, APC (silver, palladium, copper alloy), carbon, etc. It is a concept including all of and may be formed in a range that does not impair transparency by known techniques of printing, deposition, paste, and application. For example, the metal layer may be formed of a nano-Ag wire paste, or copper may be deposited, and various methods are possible. Conductive organic polymers such as PEDOT and aniline can be coated. As a method of forming the conductive layer 10, a known method such as laminating, vapor deposition, or coating may be used. For example, the thickness of the conductive layer 10 may be about 5 nm to about 500 nm, and the conductive layer 10 may have low resistance by maintaining the thickness of the conductive layer 10 in the above range.

According to one embodiment of the present invention, an antistatic layer 20 may be included on the rear surface of the base film 310 disposed with the pressure-sensitive adhesive layer 320 (FIG. 4). The antistatic layer 20 suppresses a change in luminance due to static electricity easily generated under the display due to the presence of the pattern portion 210. The antistatic layer 20 is a material different from the pressure-sensitive adhesive layer 320 and may be additionally included in the protective film 300. For example, the back surface of the base film 310 using a coating composition solution containing the above-described antistatic agent. It can be prepared by coating on.

According to one embodiment of the present invention, a light absorption layer 40, an index-matching layer 30, and a combination thereof may be included on one or both sides of the base film 310. 5 illustrates an embodiment of the protective film including the absorbent layer 40 or the index matching layer 30, the protective film of the present invention comprises one or more absorbent layers 40 and one or more index matching layers 30 May include (not shown).

The light absorption layer 40 serves to reduce a difference in reflectance between a portion where the pattern portion 210 exists and a portion where the pattern portion 210 does not exist by absorbing light of a specific wavelength reflected from the lower portion of the display panel. The light absorption layer 40 may be additionally included in the protective film 300 as a material different from the pressure-sensitive adhesive layer 320, and may include a colorant such as a dye or pigment or a light absorber that absorbs light of a specific wavelength.

The index matching layer 30 serves to improve visibility due to a difference in reflectance between a portion where the pattern portion 210 exists and a portion that does not exist. The index matching layer 30 may be an insulating layer having a refractive index capable of improving visibility. The index matching layer 30 refers to performing an optical treatment on the base film 310 so that the eye cannot detect the portion where the pattern portion 210 exists.

The index matching layer 30 is an insulation having a value between the adhesive layer 320 and the base film 310, or the base film 320 and the pattern portion or opening (for example, an air gap) 210 By forming an insulating layer on one or both sides of the base film 310 using a material, the reflectance at the layer interface is reduced by minimizing the difference in refractive index of each layer to be coated so that the presence or absence of the pattern part 210 is not confirmed. I can. Index matching of the index matching layer 30 between the pressure-sensitive adhesive layer 320 and the base film 310 is, for example, if the refractive index of the base film 310 is a and the refractive index of the pressure-sensitive adhesive layer 320 is b. The refractive index c of the layer may be a<c<b or a>c>b. The refractive index control factor may be appropriately selected according to the determined refractive index of the adhesive layer and the refractive index of the base film. The index matching layer 30 between the base film 310 and the functional film 200 improves overall visibility by canceling a difference in refractive index between the portion where the pattern portion 210 exists and the portion that does not exist. The index matching layer 30 may include SiO ₂ , TiO _2, Ceo _2, and the like by a dry method (deposition) _, or a chemical treatment by a wet method. The index matching layer 30 is a single or a plurality of insulating layer layers such as SiO ₂ , TiO _2, Ceo _2, Nb ₂ O _5, etc. _, having a refractive index capable of compensating the height of the functional film forming the pattern part 210. It can be formed in a four-layer structure.

According to one embodiment of the present invention, the OLED panel lower protective film 300 may additionally include a release film 302 at the top, and the release film is released before being applied to a display device (FIG. 6).

According to one embodiment of the present invention, the OLED panel lower protective film 300 may additionally include a carrier film 301 at the lowermost portion (FIG. 6).

Another embodiment of the present invention provides a display device to which the above-described OLED panel lower protective film 300 is applied. 2 shows an embodiment of the display device.

2, a display panel 500 including pixels positioned on a polyimide substrate 400; A fingerprint sensor 100 disposed under one surface of the display panel 500 to spatially correspond to a position of a partial area on the display panel 500; A functional film 200 having a pattern part 210 corresponding to a partial area of the fingerprint sensor to receive information about a fingerprint; And it provides a display device including the protective film 300 according to the embodiment of the present invention described above on the functional film 200.

The horizontal and vertical lengths of the opening 210 of the functional film may be equal to or less than the horizontal and vertical lengths of the fingerprint sensor 100. The opening 210 of the functional film 200 may have a shape such as a square, a circle, or a rhombus, and the shape of the opening is not limited.

In spite of the existence of the opening 210, the protective film 300 absorbs the reflected light reflected from the fingerprint sensor 100 and does not transmit it, thereby preventing poor visibility.

<Example>

Example 1:

With respect to 100 parts by weight of the acrylic copolymer consisting of 98.5 parts by weight of 2-ethyl hexyl acrylate (2-EHA) and 1.5 parts by weight of hydroxyethyl methacrylate (2-HEMA), a crosslinking agent (tolyene diisocyanate of isocyanate trimethylolpropane 1.2 parts by weight of the adduct (TDI)) was added and diluted with ethyl acetate to a solid content of 30% by weight to prepare a pressure-sensitive adhesive composition. 3 parts by weight of carbon black (HIBLACK® 900L) is dispersed with a homogenizer by adding 0.3 parts by weight of triethanolamine as a dispersant to 12 parts by weight of methyl ethyl ketone, and then homogenized by adding 1 part by weight of an antistatic agent to the pressure-sensitive adhesive composition.

Examples 2 to 5:

In place of 3 parts by weight of carbon black (HIBLACK® 900L) of Example 1, a pressure-sensitive adhesive composition was prepared in the same manner as in Example 1, except that the dyes and pigments expected in Table 1 were used.

Comparative Example 1:

With respect to 100 parts by weight of an acrylic copolymer consisting of 98.5 parts by weight of 2-ethyl hexyl acrylate (2-EHA) and 1.5 parts by weight of hydroxyethyl methacrylate (2-HEMA), a crosslinking agent (tolyene diisocyanate of isocyanate trimethylolpropane 1.2 parts by weight of an additive (TDI) and 1 part by weight of an antistatic agent were added and diluted with ethyl acetate to a solid content of 30% by weight to prepare a pressure-sensitive adhesive composition.

Comparative Example 2:

Comparative Example 1 The same pressure-sensitive adhesive composition and, and Comparative Example 1, except that the non-antistatic agent as the addition of fumed silica (Aerosil ^® R972) 7 parts by weight was added to the adhesive composition was prepared in the.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Carbon black
(Part by weight) 3 5 7 - - - - Titanium black
(Part by weight) - - - 5 - - - SYNOZOL ULTRA BLACK DR
(Part by weight) - - - - 3 - - Aerosil ^® R972
(Part by weight) - - - - - - 7

The prepared pressure-sensitive adhesive composition was coated on polyethylene terephthalate (PET) as a base film, dried in an oven at 120 °C for 3 minutes, and coated so that the thickness of the pressure-sensitive adhesive layer was 25 μm to prepare a protective film, and a release film was placed on the pressure-sensitive adhesive layer. Laminated.

<Experimental Example>

One. Measurement of transmittance/haze

The transmittance of the prepared protective film was measured using a UV-VIS-NIR Spectrophotometer (Solidspec-3700, Shimadzu Co., Ltd.), which is a transmittance/reflectance measuring device for each wavelength, and the haze value was measured based on ASTM D-1003.

2. Measurement of total reflectance and diffuse reflectance

The total reflectance and diffuse reflectance of the transmittance of the prepared protective film were determined by using a Konica Minolta CM-2600D device, using a Konica Minolta CM-2600D device, on an aluminum reflector showing a value of 55 to 65% and diffuse reflectance <1% at a wavelength of 500 nm. After positioning, the reflectance was measured on the surface of the protective film.

3. Measurement of surface resistance of adhesive surface of protective film

The prepared protective film was cut to have a horizontal length of 150 mm and a vertical length of 50 mm, and after peeling the release film from the pressure-sensitive adhesive layer, three locations were arbitrarily selected on the side of the pressure-sensitive adhesive layer from which the release film was peeled. The surface resistance was measured and the average value was calculated. Surface resistance was measured using the MCP-HT800 equipment (Mitsubishi Chemical).

4. Poor visibility evaluation

After peeling the release film from the pressure-sensitive adhesive layer, the prepared protective film was applied to the lower surface of the display panel to manufacture a display device with a pattern film and a fingerprint recognition sensor attached thereto, and then it was checked whether there was a defect in visibility found on the front of the display. .

○: Good visibility

◎: Excellent visibility

X: Poor visibility (poor visibility due to uneven luminance)

5. Fingerprint recognition rate evaluation

After peeling the release film from the pressure-sensitive adhesive layer, the prepared protective film is applied to the lower surface of the display panel to manufacture a display device with a pattern film and a fingerprint recognition sensor attached thereto, and then the fingerprint recognition rate of the user in contact with the front of the display device is determined. It was evaluated as follows.

○: Good recognition rate

◎: Excellent recognition rate

X: Poor recognition rate

6. Separation band voltage measurement

The prepared protective film was cut to have a horizontal length of 220 mm and a vertical length of 250 mm. After peeling the prepared protective film from the pressure-sensitive adhesive layer at a rate of 40 mpm, the peeling voltage was measured using an electrostatic potential meter (KSD-200) at a distance of 40 mm from the surface of the pressure-sensitive adhesive layer immediately after peeling.

Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Transmittance (%)
@400~760nm 82 70 50 60 31 99 85 Haze (%) 9 14 20 15 10.41 0.5 43 Total reflectance (%)
@400~760nm <53 <48 <40 <32 <28 59.5 57.31 Diffuse reflectance (%)
@400~760nm 0.01 0.01 0.01 0.01 0.01 0.01 31.30 Protective film adhesive surface surface resistance
(Ω/sq.) 10 ⁹ 10 ⁹ 10 ⁹ 10 ¹⁰ 10 ¹⁰ 10 ¹⁰ 10 ¹⁴ Poor visibility ○ ◎ ◎ ◎ ◎ X X Fingerprint recognition rate ◎ ◎ ○ ◎ ○ ◎ X Process film
Separation band voltage (Kv) 0.2 0.2 0.2 0.2 0.2 0.2 2

As can be seen from Table 2, the protective films according to Examples 1 to 5 have a transmittance of 30 to 85%, a total reflectance (A) of less than 55% in a wavelength range of 400 to 760 nm, and a diffuse reflectance (B). While having a value of less than 1%, the surface resistance of the pressure-sensitive adhesive layer satisfies a value of less than 1×10 ¹³ Ω/sq. As a result, no visibility defect was found on the front of the display, and no errors in fingerprint recognition were found on the front.

On the contrary, in Comparative Examples 1 and 2, the amount of light reflected toward the upper panel of the display was increased due to the high total reflectance/diffuse reflectance and high transmittance, so that all visibility defects were confirmed in the front of the display, and in the case of Comparative Example 2, fingerprint recognition It was confirmed that the error rate was also high.

100: fingerprint sensor
200: functional film 210: pattern portion or opening
300: protective film 310: base film 320: adhesive layer
10: conductive layer 20: antistatic layer
30: index matching layer 40: light absorption layer
330: conductive layer
301: carrier film
302: release film
400: polyimide (PI) substrate
500: display top panel

Claims (12)

A display panel including pixels;
A fingerprint sensor disposed under one surface of the display panel to spatially correspond to a position of a partial area on the display panel;
A functional film having a pattern portion corresponding to a partial region of the fingerprint sensor to receive information about a fingerprint; And
It is a display device including; a protective film under the display panel on the functional film,
The protective film under the display panel
Base film; And
Including; an adhesive layer on the base film,
The protective film under the display panel
Transmittance in the wavelength region of 400 to 760 nm is 60 to 85%,
In the wavelength range of 400 to 760 nm, the total reflectance (A) is less than 55% and the diffuse reflectance (B) is less than 1%,
Display device.
The method of claim 1,
A display device having a surface resistance of the pressure-sensitive adhesive layer of less than 1×10 ¹³ Ω/sq. The method of claim 1,
The pressure-sensitive adhesive layer is a display device comprising an antistatic agent. The method of claim 1,
The pressure-sensitive adhesive layer is a display device comprising a pigment, a dye, and combinations thereof. The method according to any one of claims 1 to 4,
The protective film under the display panel
Between the base film and the adhesive layer; And/or
A display device comprising at least one conductive layer on the rear surface of the base film disposed with the pressure-sensitive adhesive layer. The method according to any one of claims 1 to 4,
The protective film under the display panel includes an antistatic layer on the rear surface of the base film disposed with the pressure-sensitive adhesive layer. The method according to any one of claims 1 to 4,
The protective film under the display panel includes a light absorption layer, an index-matching layer, and a combination thereof on one or both surfaces of the base film. The method of claim 7,
The light absorbing layer is a display device comprising a colorant or a light absorbing agent. The method of claim 7,
A display device having a refractive index (c) of the index matching layer between the refractive index (b) of an upper layer adjacent to the index matching layer and a refractive index (a) of a lower layer adjacent to the index matching layer.
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