WO2018034372A1 - Compensation film, optical film, and display device provided with same - Google Patents

Abstract

The present invention relates to a foldable compensation film, and an optical film and a display device which comprise the foldable compensation film, the compensation film comprising: a first phase retardation layer comprising a polymer; and a second phase retardation layer positioned on a surface of the first phase retardation layer and comprising a liquid crystal.

Description

 【Specification】

 [Name of invention]

 Compensation film, optical film and display device having same

 Technical Field

 The present invention relates to a compensation film, an optical film, and a display device having the same.

Background Art

 Currently, a display device mainly used may be classified into a light emitting display device which emits light by itself and a light receiving display device requiring a separate light source, and a compensation film such as a retardation film is frequently used as a method for improving the image quality thereof.

 In the case of a light emitting display device, for example, an organic light emitting display device (OLED), visibility and contrast ratio may be deteriorated due to reflection of external light by a metal such as an electrode. In order to reduce this, the linearly polarized light is converted into circularly polarized light using a polarizer and a compensation film, thereby preventing external light reflected by the organic light emitting display from leaking out.

 A liquid crystal display (LCD), which is a light receiving type display device, can compensate for a phase difference caused by a liquid crystal panel using a compensation film to secure a wide viewing angle.

 However, currently developed compensation films have a strong wavelength dependence on incident light, so that they work properly for light in a specific wavelength range, but may not be effective for light in other wavelength ranges. In addition, the currently developed compensation film has a strong viewing angle dependency, and may be less visible toward the side. In addition, the currently developed compensation film has a limited foldable property and thus is limited in application to a foldable display device that is folded or bent.

 [Detailed Description of the Invention]

 [Technical problem]

In one embodiment, a compensation film for foldables having high foldable properties and capable of improving display characteristics by reducing wavelength dependence and viewing angle dependence is provided. to provide. Here, the foldable compensation film refers to a foldable or bendable compensation film that can be used in a display element that can be folded or bent. Another embodiment provides an optical film including the compensation film. Another embodiment provides a display device including the compensation film. Technical Solution

 According to an embodiment, a compensation film including a first phase retardation layer including a polymer and a second phase retardation layer disposed on one surface of the first phase retardation layer and including a liquid crystal composition are provided.

 The birefringence in the slow axis of the first phase delay layer and the second phase delay layer may satisfy the following Equations 1 to 5.

 [Relationship 1]

0.055 <Δ η _χ2 (450ηιιι)-A n _xl (450nm) <0.300

 [Relationship 2]

_{0.050 <A n x2 (550nm)} - Δ η χ1 (550ηιη) <0.250

 [Relationship 3]

_{0.045 <Δ η χ2 (650ηηι)} - Δ η χ1 (650ηηι) <0.230

 [Relationship 4]

1.00 <(Δn _x2 (450nm)-Δn _xi (450nm)) / (Δn _x2 (550nm)-Δn _xi (550nm)) <

1.21

 [Relationship 5]

0.90 <(Δ n _x2 (650 nm)-Δ n _xl (650 nm)) / (Δ n _x2 (550 nm)-Δ n _x i (550 nm)) <

1. 10

 In the above relation 1 to 5,

_{A n x i (450nm),} Δ η χ ι (550ηηι) and Δ η _χ1 and (650ηη]) is the birefringence in to the slow axis of the first phase retardation layer for the wavelength of the incident light respectively, 450nm, 550nm and 650nm, Δ η _{χ 2} (450 ηηι), Δ η _{χ 2} (550 ηπι) and Δ η _{χ 2} (650 ηι η) are the birefringence in the slow axis of the second phase retardation layer for incident light at wavelengths of 450 nm, 550 nm and 650 nm, respectively. The birefringence index at the slow axis of the first phase delay layer and the second phase delay layer may satisfy the following Equation 6.

[Relationship 6] A n _X 2 (650nm)-A n _x i (650nm) <A n _X 2 (550nm)-A n _xl (550nm) <A n _X 2 (450nm)-Δ η _χ ι (450ηηι)

 In the above relation 6,

_{A n xl (450nm), Δ} η χ1 (550ηιη) and Δ η _χ1 (650ηιτι) is the birefringence of the first phase delay layer slow axis of an incident light beam of wavelength, respectively 450nm, 550nm and 650nm, and, Δ η _χ2 ( 450 ηιτι), Δ η _{χ 2} (550 η η 0 and A n _{x 2} (650 nm) are the birefringence at the slow axis of the second phase retardation layer for incident light at wavelengths of 450 nm, 550 nm and 650 nm, respectively.

 The in-plane retardation of the compensation film with respect to incident light of 450 nm, 550 nm and 650 nm wavelengths may satisfy the following Equation 7 or 8.

 [Relationship 7]

R _e0 (450 nm) <Reo (550 nm) <R _e0 (650 nin)

 [Relationship 8]

R _e0 (450 nm) <R _e o (550 nm) <R _e0 (650 nm)

 In the above relations 7 and 8,

R _e0 (450 nm), R _e0 (550 nm) and R _e0 (650 nm) are the in-plane retardation of the compensation film with respect to 450 nm, 550 nm and 650 nm incident light, respectively.

 The in-plane retardation of the first phase retardation layer with respect to incident light at a wavelength of 550 rai may be about 220 nm to 320 nm and the in-plane retardation of the second phase retardation layer with respect to incident light at a 550 nm wavelength may be about llOnm to 160 nm.

 The polymer may include polycarbonate, cycloolefin polymer, poly (meth) acrylate, polystyrene, polymaleimide, polyacrylonitrile, polyethylene terephthalate, cellulose, derivatives thereof, copolymers thereof or combinations thereof. Can be.

 The compensation film may further include an alignment layer positioned on one surface of the second phase retardation layer.

 The compensation film may further include a reinforcement layer positioned on one surface of the second phase retardation layer and including a vertical alignment liquid crystal composition.

 The compensation film may further include an alignment layer positioned on at least one surface of the second phase retardation layer and the reinforcement layer.

According to another embodiment, comprising a polarizing element and the compensation film Provide an optical film.

 According to another embodiment, there is provided a display device including a display panel and a compensation film including a phase retardation layer including a first phase retardation layer including a polymer and a liquid crystal composition disposed on one surface of the display panel. do.

 The birefringence in the slow axis of the first phase retardation layer and the second phase retardation layer may satisfy relations 1 to 5.

 The display device may further include a polarizer disposed on one surface of the compensation film.

 Advantageous Effects

 Display characteristics can be improved by reducing wavelength dependence and viewing angle dependence, and can be applied to bent or folded display devices due to high foldable characteristics. 【Brief Description of Drawings ᅳ

 1 is a cross-sectional view showing a compensation film according to an embodiment, FIG. 2 is a cross-sectional view showing a compensation film according to another embodiment, FIG. 3 is a cross-sectional view schematically showing a compensation film according to another embodiment,

 4 is a cross-sectional view schematically showing an optical film according to one embodiment, and FIG. 5 is a schematic view showing an anti-reflective principle of the optical film of FIG. 4.

 6 is a cross-sectional view schematically illustrating an organic light emitting display device according to an embodiment.

 7 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment.

 [Best form for implementation of the invention]

 Hereinafter, embodiments will be described in detail so that those skilled in the art can easily implement the embodiments. However, embodiments may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

In order to clearly express the various layers and regions in the drawing, It is shown enlarged. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, area, plate, etc. is said "on" another part, this includes not only the other part "directly" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle. Hereinafter, a compensation film according to an embodiment will be described with reference to the drawings.

 1 is a cross-sectional view showing a compensation film according to an embodiment.

 Referring to FIG. 1, the compensation film 10 according to an embodiment includes a first phase delay layer 11, a second phase delay layer 12, and an alignment layer 13.

 The first phase retardation layer 11 may be a stretched polymer layer, or may be a stretched polymer layer having a positive or negative birefringence value. The stretched polymer pack may have foldable properties. The stretched polymer layer is, for example, polycarbonate (PC), cycloolef polymer (COP), poly (meth) acrylate, polystyrene, polymaleimide ), Polyacrylonitrile,

Polyethylene terephthalate (po 1 yet hy 1 ene terephthalate), cellulose (cellulose), derivatives thereof, copolymers thereof or combinations thereof, but is not limited thereto.

1 to the phase retardation layer 11 is in-plane retardation (in-plane retardation, the! ^ ;! is R _el

= (n _xl -n _yl ) xd ^, where n _xl is the direction in which the in-plane refractive index of the first phase retardation layer 11 is greatest (hereinafter referred to as the 'slow axis'). Is the refractive index, ₁ is the refractive index in the direction in which the in-plane refractive index of the crab 1 phase retardation layer 11 is the smallest (hereinafter referred to as the 'fast axis'), and (^ is the 1 phase retardation layer 11 Therefore, by changing the refractive index and / or the thickness at the slow axis and / or the fast axis, the first phase retardation layer 11 can be adjusted to have a predetermined range of in-plane retardation.

The first phase retardation layer 11 may have an in-plane retardation of about 220 nm to 320 nm with respect to incident light having a wavelength of 550 nm (hereinafter referred to as a 'reference wavelength'), and may have an in-plane retardation of about 240 nm to 300 nm within the above range. have. First The phase delay layer 11 may be, for example, a λ / 2 phase delay layer.

 The thinner the thickness of the first phase retardation layer 11 may be, for example, about 40 or less, for example, about 30 or less, for example, about 0.1 / im to 40 mi, for example about 0.1 / mm To 30 days.

The second phase retardation layer 12 may be a phase retardation layer comprising a liquid crystal compound having a positive or negative birefringence value, for example, an anisotropic phase retardation layer. The birefringence value is a value obtained by subtracting the refractive index n _{0 of} light traveling perpendicular to the optical axis from the refractive index n _e of light traveling horizontally with respect to the optical axis.

 The liquid crystal compound may be a rod-shaped monomer, oligomer and / or polymer extending in one direction, and the liquid crystal compound may be, for example, a compound represented by the following general formula (1) or (2).

 [Formula 1]

P ^ S ^ MG-R ¹

 In the general formula 1,

P ¹ is a polymerizable functional group,

S ¹ is a C1 to C20 alkylene group, provided that at least one CH ₂ or at least _two non-adjacent C¾ of the alkylene groups may be each independently substituted with an oxygen atom — — C00-,-0C0- or -0C00-,

 MG is a mesogenic group

R ¹ is a hydrogen atom, a halogen atom, a cyano group or a C1 to C12 alkyl group, the alkyl groups are each at least one CH ₂ or at least two CH ₂ non-adjacent independent ~ 0-, -S-, -CO-, -C00-, -0C0- or "0C00- can be substituted.

 [Formula 2]

P ^ S ^ MG- S ² -P ²

 In the general formula 2,

P ¹ and P ² are each independently a polymerizable functional group,

S ¹ and S ² is replaced by a C1 to C20 alkylene group, provided that the alkylene group one or more CH ₂ or non-adjacent two or more of the CH ₂ are each independently an oxygen atom, -C00-, -0C0- or "0C00- Can be MG is a mesogenic group.

 In Formula 1 or 2, the mesogenic group represented by MG may be represented by, for example, the following Formula 3.

 [Formula 3]

 In the general formula 3,

B ¹ , B ^2, and B ³ are each independently 1,4-phenylene group, 1,4-cyclonuclear group, 1,4—cyclonucleenyl group, decahydronaphthalene-2, 6-diyl group, pyridine- 2,5-diyl group, pyrimidine _2,5-diyl group, 1,2,3,4-tetrahydronaphthalene-2,6-diyl group or 2,6-naphthylene group, these may be, for example, one or more F, CI, CF ₃ , 0CF ₃ , CN, C1 to C8 alkyl group, C1 to C8 alkoxy group, C1 to C8 alkanoyl group, C2 to C8 alkenyl group or C2 to C8 alkenyloxy group,

Z ¹ and Z ² are each independently a single bond, a C2 to C10 alkyl group unsubstituted or substituted with a halogen atom, -C00-, -0C0-, -CH ₂ CH _2- , -CH = CH-, -C≡C- May be -CH = CHC00- or -0C0CH = CH-,

 n may be 0, 1 or 2.

In Formula 1 or 2, the polymerizable functional groups represented by P ¹ and P ² may be, for example, an acrylic group, a methacryl group, an epoxy group, or a vinyl group, and may be, for example, an acrylic group or a methacryl group, for example, an acrylic group. .

 The two-phase retardation layer 12 may include one or two or more liquid crystal compounds.

The second phase retardation layer 12 may be formed from the liquid crystal composition including the liquid crystal compound described above, and the liquid crystal composition may include, in addition to the liquid crystal compound, various additives and solvents such as reaction initiators, surfactants, dissolution aids, and / or dispersants. can do. The liquid crystal composition may be applied by, for example, a coating process such as spin coating, slit coating, and / or inkjet, and a drying process may be applied after application as necessary. The thickness can be adjusted in consideration of the refractive index and the like of the phase 2 retardation layer 12 during the coating process. After the liquid crystal composition is applied, a polymerization process may be applied by heat or light, and in the case of a photocuring process, the liquid crystal composition may be cured to ultraviolet light of about 250 nm to 400 nm. have.

The in-plane retardation R _e2 of the second phase retardation layer 12 can be given by R _e2 = (n _x2 -n _y2 ) xd ₂ , where n _x2 is the slow axis of the crab phase retardation layer 12. Is the refractive index, ₂ is the refractive index at the fast axis of the second phase retardation layer 12, and d ₂ is the thickness of the second phase retardation layer 12. Therefore, the second phase retardation layer 12 can be adjusted to have a predetermined range of in-plane retardation by varying the refraction and / or thickness in the slow axis and / or the fast axis.

 The second phase retardation layer 12 may have an in-plane retardation of about llOnm to 160 nm with respect to incident light of a reference wavelength, and may have an in-plane retardation of about 120 nm to 150 nm within the above range. The second phase delay layer 12 may be, for example, a quarter phase delay layer.

 The alignment layer 13 may be positioned below the second phase retardation layer 12 to control the alignment of the liquid crystal composition of the two phase retardation layer 12. The alignment film 13 may be surface treated by physical treatment such as rubbing or light treatment such as light alignment. The alignment layer 13 may be omitted in some cases.

 The thickness of the alignment layer 13 may be about 100 nm or less, may be about 70 nm or less in consideration of adhesion, may be about 50 nm or less within the above range, for example about 40 nm or less within the above range. The thickness of the alignment layer 13 may be, for example, about lnm to 100nm, and may be, for example, about 3nm to 70nm, within the range, for example, about 5nm to 50nm, within the range, for example, about 5nm to It can be 40nm.

 The first phase retardation layer 11 and the second phase retardation layer 12 may be combined to implement a compensation film having an in-plane retardation of about llOnm to 160 nm, for example, a compensation film having a λ / 4 phase delay layer. have.

 By combining the first phase delay layer 11 and the second phase delay layer 12, a compensation film 10 having a reverse wavelength dispersion phase delay can be realized. The reverse wavelength dispersion phase delay refers to the fact that the in-plane retardation of the long wavelength light is larger than the in-plane retardation of the short wavelength light. For example, the crab 1 phase delay layer 11 and the crab 2 phase delay layer 12 are combined to Equation 7 or 8 may be satisfied.

[Relationship 7] R _e0 (450 nm) <Reo (550nm) <Reo (650nm)

 [Relationship 8]

Reo (450nm) <R _e o (550nm) <R _e0 (650nm)

 In the above relation 7 or 8,

R _e0 (450 nm), R _e0 (550 nm) and R _e0 (650 nm) are the in-plane retardation of the compensation film with respect to 450 nm, 550 nm and 650 nm incident light, respectively.

 On the other hand, the compensation film 10 including the first phase retardation layer 11 and the second phase retardation layer 12 by adjusting the optical characteristics of the first phase retardation layer 11 and the second phase retardation layer 12. It can enhance the compensation function for the wavelength dependency and the viewing angle dependency of the.

 For example, the compensation function of the compensation film 10 may be enhanced by controlling the birefringence difference and the birefringence wavelength dispersion in the slow axis of the first phase delay layer 11 and the second phase delay layer 12. Here, the wavelength dispersion of the birefringence indicates the degree of change in the birefringence relative to the reference wavelength, and the short wavelength dispersion indicating the degree of change in the birefringence of the short wavelength relative to the reference wavelength and the long wavelength indicating the degree of change in the birefringence of the long wavelength relative to the reference wavelength Includes dispersibility

 For example, the birefringence at the slow axis of the system 1 phase delay layer 11 and the second phase delay layer 12 may satisfy the following relations 1 to 5.

 [Relationship 1]

0.055 <An _x2 (450 nm)-An _x i (450 nm) <0.300

 [Relationship 2]

0.050 <Δη _χ2 (550ηιη)-An _x i (550nm) <0.250

 [Relationship 3]

_{0.045 <Δη χ2 (650ηιη) -} Δη χ1 (650ηιη) <0.230

 [Relationship 4]

1.00 <(Δn _x2 (450nm)-Δn _xi (450nm)) / (Δn _x2 (550nm)-Δn _x i (550nm)) <

1.21

 [Relationship 5]

_{0.90 <(Δη χ2 (650ηπι)} -Δη χ1 (650ηιτι)) / (Δη Χ 2 (550ηιη) -Δη χ1 (550ηιιι)) < In the above relation 1 to 5,

_{An x i (450nm), An} xl (550nm) and Δη _χ1 (650ηιη) is the birefringence of the first phase delay layer slow axis of about 450皿, 550nm and incident light of the 650nm wavelength, respectively, An _x2 (450nm) , Δη _χ2 (550ηηι) and Δη _χ2 (650ηηι) are 450nm, 550nm and

It is the birefringence in the slow axis of the second phase retardation layer for incident light of 650 nm wavelength. That is, relations 1 to 3 relate to the birefringence difference between the first phase delay layer 11 and the crab two phase delay layer 12, and relations 4 and 5 correspond to the first phase delay layer 11 and the crab two phase delay layer. (12) relates to the wavelength dispersion of the birefringence of the birefringence, the difference between each of the birefringence in the slow axis of the first phase retardation layer 11 and the second phase retardation layer 12 for incident light of 450nm, 550nm and 650nm wavelength When the ratio of wavelength dispersion of the refractive index is within a predetermined range, the compensation function for wavelength dependence and viewing angle dependence can be enhanced.

 Each birefringence in the slow axis of the U phase retardation layer 11 and the second phase retardation layer 12 may satisfy, for example, the following relations 1-1 to 5-1.

 [Relationship 1-1]

_{0.080 <Δη χ2 (450ηιη) -} Δη χ1 (450ηιτι) <0.240

 [Relationship 2-1]

_{0.070 <Δη χ2 (550ηιη) -} Δη χ1 (550ηιτι) <0.210

 [Relationship 3-1]

0.070 <Δη _χ2 (650ηηι)-An _xl (650nm) <0.200

 [Relationship 4-1]

_{1.10 <(Δη χ2 (450ηιη)} -Δη χ ι (450ηηι)) / (Δη Χ 2 (550ηιη) -Δη χ1 (550ηιτι)) <1.18

 [Relationship Formula 5-1]

_{0.90 <(Δη χ2 (650ηιιι)} -Δη χ ι (650ηιιι)) / (Δη Χ 2 (550ηιτι) -Δη χ1 (550ηιη)) <

0.98

oe trv to(oi) ¾ i ff -ts- o --bi¾ ^ foS 륭^ ¾t5 1¾οί Each birefringence in the slow axis of the U phase retardation layer 11 and the second phase retardation layer 12 may satisfy the following relations 1-2 to 5-2 within the above range. II tp (Oi): i ff Long Dragon i½ Dragon

oe trv to (oi) ¾ i ff -ts- o --bi¾ ^ foS Excellent ^ ¾t5 1¾οί

P ¾to 1¾¼ tp (0I) ¾ -ι ° ν

 [^^ [o (ZI) ^^ -trr (IT) ^) k v ^

^• The-b ^ io ^ ^ to eoP? l si

uraogg

(uiuogg)Z^xuv ' (urao ) ^Z¾V ^' ᅳ ^ 눚 [o

uraogg

(uiuogg) Z ^x uv '(urao) ^Z¾ V

WU0S9 'ϊΓίο ^^ 눚 tokl ½i ° vk t0 po

WU0S9

^ uiuogg '丽 0-^ (muOS9) ^TXu V ^ (uiuogg) ΐ¾ν' (ωυ () ^τ¾ ν OC

-(uiuog ^) z ^x uv> (uiuogg) ^I ¾v- (unJOS9) ^zx uV> ( ^luu OS9) ^TXu V- ( ^UIU OG9) ^2Xu V

 [9

¼ i 금롤^론눚 51

¼ i Gold roll ^ Ron 눚 51

S6.0

> ((uraog5) ^ ^x uv- (uiu099) ^zx uv) / ((uiu099) ^TXu V- (™ 099) ^SXu V)> S6 ^" 0

9Τ ^'' ΐ Οΐ

> ((0) ^τχ υν- (而 0) ^sx uv) / ((0S) ^Ix uv- (ura ())>οΐ'ΐ

Ι6Γ0> (uiuoS9) ^TX uV-(0S9) ^SX UV> 2 0Ό

802 Ό> (uraogg) ^TX uy-(uniOSS) ^z ¾V> SZO ^'' OS

L £ Z ^' 0> (uniog) ^TX uV-

Z.6T600 / 9lOZaM / X3d The reward function can be enhanced.

 The compensation film 10 may, for example, prepare the first phase retardation layer 11 and the second phase retardation layer 12 in the form of a film, and then attach them to each other, and then the alignment film 13 on the first phase retardation layer 11. And the second phase retardation layer 12 may be formed by coating. The second phase retardation layer 12 may be formed by coating, drying, and light irradiation of the liquid crystal composition, but is not limited thereto.

 Hereinafter, a compensation film according to another embodiment will be described.

 2 is a cross-sectional view showing a compensation film according to another embodiment.

 Referring to FIG. 2, the compensation film 10 according to the present embodiment includes the first phase delay layer 11, the second phase delay layer 12, and the alignment layer 13, similarly to the above-described embodiment.

 However, the compensation film 10 according to the present embodiment further includes a reinforcing layer 14 and an alignment layer 15.

 The reinforcement layer 14 may be a liquid crystal layer including a vertically oriented liquid crystal composition oriented perpendicular to the plane direction of the crab 1 phase retardation layer 11 and the second phase retardation layer 12.

The in-plane retardation R _e3 of the reinforcing layer 14 can be given by R _e3 = (n _x3 -n _y3 ) xd ₃ , where n _x3 is the refractive index at the slow axis of the reinforcing layer 14, and ₃ is the reinforcing layer ( It is the refractive index in the fast axis of 14, and d <_3> is the thickness of the reinforcement layer 14.

In-plane retardation of the reinforcing layer (14) (R _e3) is, for example 0nm≤R _e3 may be ≤50nm, e.g. 0nm≤R _e3 may be ≤20nm, e.g. 0nm≤R _e3 may be ≤ 10nm, for example 0nm≤R _e3 <5nm, 0rai≤R _e3 <lnm, and may be substantially zero. On the other hand, the retardation has a thickness retardation R _{th in} addition to the in-plane retardation. The thickness direction retardation R _th is a phase difference occurring in the thickness direction of the reinforcing layer 14 and may be expressed as R _th3 = {[((n _x3 + n _y3 ) / 2] -n _z3 } d ₃ , where n _x3 Is the refractive index at the slow axis of the reinforcing layer 14, ₃ is the refractive index at the fast axis of the reinforcing layer 14, n _z3 is the refractive index in the direction perpendicular to the slow and slow axes of the reinforcing layer 14, d ₃ is the thickness of the reinforcing layer 14. Retardation (R _th) in the thickness direction of the reinforcing layer 14 may be, for example, 50nm≤R _th ≤300nm.

The reinforcing layer 14 may have, for example, a refractive index that satisfies the following equation (9). have.

 [Relationship 9]

n _z3 > n _x3 = n _y3

 The reinforcing layer 14 can further enhance the compensation function by reducing the viewing angle dependence and the wavelength dependence by reducing or canceling the thickness direction retardation between the first phase retardation layer 11 and the second phase retardation layer 12.

 The alignment layer 15 may be positioned below the reinforcement layer 14 to serve to orient the liquid crystal composition of the reinforcement layer 14 perpendicularly to the substrate. The alignment film 15 may be, for example, a polyimide resin, a polyamide resin, a photo alignment film or the like having an alkyl group or a fluorine group introduced therein. The alignment film 15 may be omitted in some cases.

 The compensation film 10 may, for example, prepare the first phase retardation layer 11, the second phase retardation layer 12, and the reinforcing layer 14 in the form of a film, and then attach them to each other. The alignment film 13, the two-phase retardation layer 12, the alignment film 15, and the reinforcing layer 14 may be coated on each other. The two phase retardation layer 12 and the reinforcing layer 14 may be formed by coating, drying, and irradiating the liquid crystal composition, respectively, but are not limited thereto.

 Hereinafter, a compensation film according to another embodiment will be described.

 3 is a schematic cross-sectional view of a compensation film according to another embodiment.

 Referring to FIG. 3, the compensation film 10 according to the present embodiment may include the first phase retardation layer 11, the second phase retardation layer 12, the alignment layer 13, and the reinforcement layer 14, as in the above-described embodiment. It includes.

 However, in the compensation film 10 according to the present embodiment, the reinforcing layer 14 is positioned between the first phase retardation layer 11 and the second phase retardation layer 12. The detailed description of the first phase retardation layer 11, the second phase retardation layer 12, the alignment layer 13, and the reinforcement layer 14 is as described above.

The above-described compensation film 10 has a layered foldable property and can be bent or folded without cracking. The radius that can be bent or folded here may be 8 mm or less, of which 5 mm or less, of which 3 mm or less. It may be less than 1 隱 among them.

 The compensation film 10 described above may be used together with a polarizer to form an optical film having an external light reflection preventing function.

 Hereinafter, an optical film according to one embodiment is described.

 4 is a schematic cross-sectional view of an optical film according to an embodiment. Referring to FIG. 4, the optical film 30 according to the embodiment includes a compensation film 10 and a polarizer 20.

 The compensation film 10 may be one of the embodiments described above, and details are as described above.

 The polarizer 20 may be disposed on the side where the light is incident, and may be a linear polarizer that converts the polarized light of the incident light into linearly polarized light. The polarizer 20 may be made of, for example, stretched polyvinyl alcohol (PVA), for example, by stretching a polyvinyl alcohol film, adsorbing an iodine or dichroic dye thereto, and then treating with boric acid and washing. Can be formed.

 The polarizer 20 may be a polarizing film prepared by melt blending a polymer resin and a dichroic dye, for example, and may be formed by mixing the polymer resin and a dichroic dye and then melting the polymer resin at a temperature above the melting point of the polymer resin. have.

The first phase retardation layer 11 and the second phase retardation layer 12 may be circularly polarized by bonding at a predetermined angle, and specifically, the angle formed by the optical axis of the first phase retardation layer 11 with respect to the reference angle. when defined as θ _3, and define the angle between the optical axis of the second phase retardation layer 12 forms with respect to a reference angle e _b e _b = 2θ ₃ +

When the relationship of 45 ^° is satisfied, the compensation film can function to convert linearly polarized light into circularly polarized light. Here, the reference angle may be an angle of the optical axis of the polarizer 20, and the optical axis of the polarizer 20 may be an absorption axis or a transmission axis of the polarizer 20. For example, the slow axes of the first phase delay layer 11 and the second phase delay layer 12 may be bonded to satisfy approximately e _b = 2Θ ₃ + 45 ^° , for example, the optical axis of the polarizer 20 and the first axis. When the angle of the phase retardation layer 11 is about 15 degrees, the first phase retardation layer 11 and the second phase retardation layer 12 may be joined at an angle of about 60 degrees. For example, when the angle of the optical axis of the polarizer 20 and the angle of the first phase retardation layer 11 is about 10 degrees, the first phase retardation layer 11 and the second phase retardation layer 12 may be joined at about 55 degrees. For example, when the angle of the optical axis of the polarizer 20 and the first phase retardation layer 11 is about 20 degrees, the first phase retardation layer 11 and the second phase retardation layer 12 may be bonded to about 65 degrees.

 Thus, the first phase retardation layer 11 and the second phase retardation layer 12 are bonded at a predetermined angle and have a circular polarization function to effectively prevent external light reflection from the front, thereby improving front visibility. can do.

 FIG. 5 is a schematic diagram illustrating an external light reflection prevention principle of the optical film of FIG. 4.

 Referring to FIG. 5, incident unpolarized light incident from the outside passes through the polarizer 20 while transmitting only one polarization orthogonal component, that is, the first polarization orthogonal component, of two polarization orthogonal components. And polarized light may be changed into circularly polarized light while passing through the compensation film 10. The circularly polarized light is reflected by the display panel 40 including a substrate, an electrode, and the like, and the circularly polarized light is changed, and the circularly polarized light passes through the compensation film 10 again, and thus the other of the two polarized orthogonal components Only the polarized orthogonal component, ie the second polarized orthogonal component, can be transmitted. Since the second polarized orthogonal component does not pass through the polarizer 20 and no light is emitted to the outside, it may have an anti-reflection effect.

 The optical film 30 may further include a protective layer (not shown) on one surface of the polarizer 20. The protective layer may be provided to improve the durability of the optical film 30 or to further enhance the functionality to reduce reflection or glare, for example, may be a triacetyl cellulose (TAC) film, but is not limited thereto.

 The optical film 30 may further include a correction layer (not shown) positioned on one surface of the compensation film 10. The correction layer may be, for example, a color shift resist layer, but is not limited thereto.

The optical film 30 may further include a light blocking layer (not shown) extending along the edge. The light shielding layer is optical It may be formed in the form of a band along the circumference of the film (30). The light blocking layer may include an opaque material, for example, a black material. For example, the light shielding layer may be made of black ink.

The optical film 30 is a compensation film 10 and the polarizer 20-to-the _(ro l l-to- rol l), but can be coated or laminated to the transfer method, and the like. ·

 Optical film 30 has sufficient foldable properties and can bend or fold without cracking.

 The aforementioned compensation film 10 and optical film 30 can be applied to various display devices.

 The display device according to an embodiment includes a display panel and a film positioned on one surface of the display panel.

 The display panel may be a liquid crystal display panel or an organic light emitting display panel. The display panel may be, for example, a foldable liquid crystal display panel or a foldable organic light emitting display panel, for example, a bent liquid crystal display panel (bendable LCD), a bent organic light emitting display panel (bendable 0LED), a collapsible liquid crystal display panel ( foldable LCD) or a collapsible organic light emitting display panel (foldable 0LED), but is not limited thereto.

 The film may be the compensation film 10 or the optical film 30 described above. Hereinafter, an organic light emitting diode display will be described as an example of a display device. 6 is a cross-sectional view schematically illustrating an organic light emitting display device according to an embodiment.

 Referring to FIG. 6, an organic light emitting diode display according to an exemplary embodiment includes an organic light emitting display panel 600 and a film 700 positioned on one surface of the organic light emitting display panel 600.

 The organic light emitting display panel 600 may include a base substrate 610, a lower electrode 620, an organic emission layer 630, an upper electrode 640, and an encapsulation substrate 650. Base substrate 610 may be made of glass or plastic.

One of the lower electrode 620 and the upper electrode 640 may be an anode and the other may be a cathode. The anode is injected with a hole The electrode may be made of a conductive material having a high work funct ion, and the cathode may be made of a conductive material having a low work function as an electrode into which electrons are injected. At least one of the lower electrode 620 and the upper electrode 640 may be made of a transparent conductive material through which emitted light can come out, for example, IT0 or IZ0.

 The organic emission layer 630 includes an organic material that can emit light when a voltage is applied to the lower electrode 620 and the upper electrode 640.

 An auxiliary layer (not shown) may be further included between the lower electrode 620 and the organic light emitting layer 630 and between the upper electrode 640 and the organic light emitting layer 630. Subsidiary layers include a hole transporting layer, a hole injecting layer, an electron injecting layer, and an electron transporting layer to balance electrons and holes. It may include, but is not limited to.

 The encapsulation substrate 650 may be made of glass, metal, and / or polymer, and encapsulate the lower electrode 620, the organic light emitting layer 630, and the upper electrode 640 so that moisture and / or oxygen may be introduced from the outside. It can prevent.

The film 700 may be disposed on the side from which light comes out. For example, in the case of a bottom emission structure in which light is emitted toward the base substrate 610, a top emission structure may be disposed outside the base substrate 610, and the light is emitted toward the encapsulation substrate 650. In this case, the encapsulation substrate 650 may be disposed outside the encapsulation substrate 650. ^The film 700 may be the compensation film 10 or optical film 30 described above. For example, when the film 700 is the optical film 30, external light introduced through the optical film 30 is reflected by a reflective layer made of metal, such as electrodes and wirings of the organic light emitting display panel 600, so that the outside of the display device may be reduced. The display characteristics of the organic light emitting diode display may be improved by preventing the light emission from occurring.

 Hereinafter, the liquid crystal display device will be described as an example of the display device.

 7 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment.

Referring to FIG. 7, the liquid crystal display according to the embodiment is a liquid crystal display. The panel 800 and the film 700 positioned on one surface of the liquid crystal display panel 800 are included. The liquid crystal display panel 800 is in twisted nematic (twi st nemat ic, TN) mode, vertically oriented (patterned vert i cal al ignment (PVA) mode, in-plane swi tching (IPS) mode, OCBCopt ical ly compensated bend) mode and the like.

 The liquid crystal display panel 800 includes a first display panel 810, a second display panel 820, and a liquid crystal layer 830 interposed between the first display panel 810 and the second display panel 820.

The U-display panel 810 may include, for example, a thin film transistor (not shown) formed on a substrate (not shown) and a first field generating electrode (not shown) connected thereto. 820 may include, for example, a color filter (not shown) and a nearly 12 field generating electrode (not shown) formed over a substrate (not shown). However, the present invention is not limited thereto, and the color filter may be included in the first display panel 810, and the first field generating electrode and the second ^' field generating electrode may be disposed together on the first display panel 810.

 The liquid crystal layer 830 may include a plurality of liquid crystal molecules. The liquid crystal molecules may have positive or negative dielectric anisotropy. When the liquid crystal molecules have positive dielectric anisotropy, their long axes are oriented so as to be substantially parallel to the surfaces of the first display panel 810 and the second display panel 820 in the absence of an electric field, and the long axes of the liquid crystal molecules are in a state where an electric field is applied. The display panel may be aligned to be substantially perpendicular to the surfaces of the first display panel 810 and the second display panel 820. On the contrary, when the liquid crystal molecules have negative dielectric anisotropy, in the absence of an electric field, the major axis thereof is oriented almost perpendicular to the surfaces of the crab 1 display panel 810 and the crab 2 display panel 820, and the liquid crystal molecules have a negative dielectric anisotropy. The major axis may be oriented almost parallel to the surfaces of the first display panel 810 and the second display panel 820.

The film 700 may be the compensation film 10 or the optical film 30 described above. The film 700 is positioned outside the liquid crystal display panel 800, and in the drawing, the film 700 is formed on the lower and upper portions of the liquid crystal display panel 800, but It is not limited thereto and may be formed only in any one of the lower part and the upper part of the liquid crystal display panel 800.

 [Form for implementation of invention]

 Through the following examples will be described in more detail the embodiment of the present invention. However, the following examples are for illustrative purposes only and do not limit the scope of the present invention.

 Preparation of Liquid Crystal Composition

 (1) Preparation of Liquid Crystal Composition for Second Phase Delay Layer

 In order to use it for a 2nd phase retardation layer, 5 types of polymeric liquid crystals (made by DIC Corporation) which have the characteristics of Table 1 are prepared.

 Table 1

 (2) Preparation of liquid crystal material for reinforcement layer

 In order to use it for a reinforcement layer, the polymeric liquid crystal (made by DIC Corporation) which has the characteristic of Table 2 is prepared.

Table 2

 (3) quasi-finding of the alignment film material

 PAM-0021 (made by DIC Corporation) is used as a photo-alignment film material. On the other hand, the photo-alignment film for aligning the liquid crystal composition of the second phase retardation layer is formed by applying the photo-alignment film material and then irradiating polarized UV light, and the photo-alignment film for aligning the liquid crystal composition of the reinforcing layer provides UV light with no polarization. Form by irradiation.

 Preparation of Compensation Film

Example 1 (1) Preparation of a Crab 1 Phase Delay Layer

A polycarbonate film was uniaxially stretched (using an Instron tensile tester) at 1.45 times at 130 ^° C. to prepare a first phase retardation layer (R _el = 257 nm) having a thickness of 30 m.

 (2) Preparation of the second phase retarder

After spin coating the photoalignment film material (P 層 -0021) on the first phase retardation layer and drying at 80 ^° C. for 3 minutes, lOOmJ such that an angle of 60 ± 2 degrees with respect to the slow axis of the first phase retardation layer is in the polarization direction. Irradiation of / ciif polarized UV light to form a photoalignment film. Subsequently, the liquid crystal 4 JCL-017S8) shown in Table 1 was spin-coated on the photoalignment film, dried at 80T: for 2 minutes, cooled to room temperature, and irradiated with UV light at 600 mJ / ciif to form a crab 2-phase retardation layer having a thickness. Prepare the film. When forming the second phase retardation layer, the number of rotations of the spin coating is adjusted so that the in-plane retardation of the second phase retardation layer is 134 ± 2 nm.

 Example 2

 A compensation film was prepared in the same manner as in Example 1 except for using Liquid Crystal 2 JCL-017S6 described in Table 1 instead of Liquid Crystal 4 in preparing the second phase delay layer.

 Example 3

 In the preparation of the second phase retardation layer, a compensation film was prepared in the same manner as in Example 1, except that a 0.9-thick crab 2-phase retardation layer was formed using the liquid crystal KUCL-017S4 shown in Table 1 instead of the liquid crystal 4. .

 Example 4

 In preparing the second phase retardation layer, a compensation film was prepared in the same manner as in Example 1 except that a 1.6-thick crab 2 phase retardation layer was formed using the liquid crystal 3 UCL-017S7 shown in Table 1 instead of the liquid crystal 4. do.

 Example 5

 A compensation film was prepared in the same manner as in Example 1 except that the C1 phase retardation layer was formed to a thickness of 40 / m.

 Example 6

A compensation film was prepared in the same manner as in Example 2, except that the C 1 phase retardation layer was formed to have a thickness of 40. Example 7

 A compensation film was prepared in the same manner as in Example 3 except that the U phase retardation layer was formed to a thickness of 40.

 Example 8

Cycloolefin polymer film (ZenorFi lm ^® , instead of polycarbonate film)

A compensation film was prepared in the same manner as in Example 1 except that the first phase retardation layer having a thickness of 40 m was prepared using Zeon, R _el = 257 nm).

 Example 9

A compensation film was prepared in the same manner as in Example 2, except that a first phase retardation layer having a thickness of 40 / ΛΠ was prepared using a cycloolefin polymer film (ZenorFilm ^® , Zeon, R _el = 257 nm) instead of the polycarbonate film. do.

 Example 10

Polycarbonate film used instead of cycloolefins increased polymer film ^{(ZenorFi lm ®, Zeon, R} el = 257nm) to prepare a compensation film in the same manner as in Example 3 except that the preparing the first phase delay layer to the thickness.

 Example 11

Using the polycarbonate film instead of cycloolefins polymer film ^{(ZenorFi lm ®, Zeon, R} el = 257nm) to the compensation film is prepared in the same manner as in Example 3 except for preparing a first phase delay layer having a thickness.

 Example 12

Polycarbonate to the film using instead cycloalkyl olefin polymer film ^{(ZenorFi lm ®, Zeon, R} el = 257nm) to prepare a compensation film in the same manner as in Example 4 except that the preparing the first phase retardation layer 40 thickness.

 Example 13

Prepare the first phase retardation layer and the second phase retardation layer in the same manner as in Example 3 ᅳ Then spin-coat the optical alignment film material (PAM-0021) on the second phase retarder and dry at 80 ^° C. for 3 minutes, Irradiation of unpolarized UV light of 100 mJ / crf forms a photo alignment layer. Subsequently, the liquid crystal 6 (UCL-018SC1) shown in Table 2 was spin-coated on the photoalignment film, dried at 80 ^° C. for 2 minutes, cooled to room temperature, and irradiated with UV light at 600 mJ / cuf to form a reinforcement layer to prepare a compensation film. . When the reinforcing layer is formed, the number of rotations of the spin coating is adjusted so that the thickness retardation (Rth) of the reinforcing layer is 65 ± 10 nm.

 Example 14

In the same manner as in Example 1, a first phase delay layer and a second phase delay layer are prepared. Subsequently, the optical alignment layer material (PAM-0021) is spin-coated on the second phase retardation layer, dried at 80 ^° C. for 3 minutes, and irradiated with unpolarized UV light of 100 mJ / oif to form a photo alignment layer. Subsequently, the liquid crystal 6 (UCL-018SC1) shown in Table 2 was spin-coated on the photoalignment film, dried at 80 ^° C. for 2 minutes, cooled to room temperature, and irradiated with UV light at 600 mJ / cuf to form a reinforcing layer to prepare a compensation film. . When the reinforcing layer is formed, the number of rotations of the spin coating is adjusted so that the thickness retardation (R _th ) of the reinforcing layer is 65 ± 10 nm.

 Comparative Example 1

After spin-coating the photoalignment film material (PAM-0021) on a Z-TAC film (manufactured by Fuj ifi lm) and drying at 80 ^° C. for 3 minutes, a photoalignment film was formed by irradiating 100mJ / ciif unpolarized UV light. do. Subsequently, the liquid crystal 4 UCL-017S8 of Table 1) was spin-coated on the photoalignment film, dried at 80 ^° C. for 2 minutes, cooled to room temperature, and irradiated with UV light at 600 mJ / ciif to form a crab phase retardation layer. When forming the U phase retardation layer, the number of rotations of the spin coating is adjusted so that the in-plane retardation of the first phase retardation layer is 257 ± 10 nm.

Subsequently, after spin coating the photoalignment film material (PAM-0021) on the first phase retardation layer and drying at 80 ^° C. for 3 minutes, the lOOmJ angle is 60 ± 2 degrees with respect to the slow axis of the first phase retardation layer. Irradiating polarized UV light of / cuf to form a photoalignment film. Subsequently, the liquid crystal 2 JCL-017S6) shown in Table 1 was spin-coated on the photoalignment film, dried at 8C C for 2 minutes, cooled to room temperature, and irradiated with 600mJ / cu UV light to form a second phase retardation layer. When the _two phase retardation layer is formed, the in-plane retardation of the two phase retardation layer

Adjust the spin coating speed to 134 ± 2nm.

 Comparative Example 2

A compensation film was prepared in the same manner as in Comparative Example 1 except for using the liquid crystal ι (υα-017S4) shown in Table 1 instead of the liquid crystal 2 in preparing the second phase delay layer. Prepare.

 Comparative Example 3

 In the preparation of the second phase retardation layer, a compensation film was prepared in the same manner as in Comparative Example 1 except that Liquid Crystal 3 JCL-017S7) described in Table 1 was used instead of Liquid Crystal 2.

 Comparative Example 4

 Except that liquid crystal 2 UCL-017S6) as described in Table 1 was used instead of liquid crystal 4 in the preparation of the first phase retardation layer and liquid crystal 4 JCL-017S8 as described in Table 1 was used instead of the liquid crystal 2 in the preparation of the second phase delay layer. Prepare a compensation film in the same manner as in Comparative Example 1.

 Comparative Example 5

 Except for using liquid crystal 2 UCL-017S6 described in Table 1 instead of liquid crystal 4 in the preparation of the first phase retardation layer and using liquid crystal 1 (UCL-017S4) described in Table 1 in place of the liquid crystal 2 in preparing the second phase retardation layer. Then, a compensation film is prepared in the same manner as in Comparative Example 1.

 Comparative Example 6

 Except for using liquid crystal 2 UCL-017S6 shown in Table 1 instead of liquid crystal 4 in the preparation of the first phase retardation layer and using liquid crystal 3 (UCL-017S7) shown in Table 1 in place of the liquid crystal 2 in preparing the second phase retardation layer. Then, a compensation film is prepared in the same manner as in Comparative Example 1.

 Comparative Example 7

 Except that liquid crystal 1 JCL-017S4) as described in Table 1 was used instead of liquid crystal 4 in the preparation of the first phase retardation layer, and liquid crystal 4 UCL-017S8 as described in Table 1 was used instead of the liquid crystal 2 in the preparation of the second phase delay layer. Prepare a compensation film in the same manner as in Comparative Example 1. Comparative Example 8

In the preparation of the U phase retardation layer, the liquid crystal 1 JCL-17S4 shown in Table 1 was used instead of the liquid crystal 4, and the liquid crystal 2 (UCL-017S6) shown in Table 1 was used instead of the liquid crystal 2 in the preparation of the phase 2 retardation layer. A compensation film is prepared in the same manner as in Comparative Example 1 except for the above. Comparative Example 9

 Except that liquid crystal KUCL-017S4) as described in Table 1 was used instead of liquid crystal 4 in the preparation of the first phase retardation layer and liquid crystal 3 JCL-017S7) as described in Table 1 was used instead of the liquid crystal 2 in the preparation of the phase 2 delay layer. A compensation film is prepared in the same manner as in Comparative Example 1.

 Comparative Example 10

 In preparing the second phase retardation layer, a compensation film was prepared in the same manner as in Example 1, except that the second phase retardation layer was formed using the liquid crystal 5 JCL-017S9 shown in Table 1 instead of the liquid crystal 4.

 Examples 1 to 14 and Comparative Examples 1 to 10 are as shown in Tables 3 and 4.

[Table 3]

 Table 4

1 phase delay layer thickness 12 phase delay layer reinforcement layer material thickness Comparative Example 1 Liquid Crystal 4 1.22 Liquid Crystal 2 0.71

 η ㅁ Comparative Example 2 Liquid Crystal 4 1.23 Liquid Crystal 1 0.90 \ Comparative Example 3 Liquid Crystal 4 1.22 Liquid Crystal 3 1.54 Uh Comparative Example 4 Liquid Crystal 2 1.36 Liquid Crystal 4 0.63 WA Comparative Example 5 1 ᄋ 1.35 Liquid Crystal 1 0.88 Liquid Comparative Example 6 Liquid Crystal 2 1.37 Liquid Crystal 3 1.52 ¾Λ ‡ Comparative Example 7 Liquid Crystal 1 1.73 Liquid Crystal 4 0.63 o

 ¾λ ‡ Comparative Example 8 Liquid Crystal 1 1.69 a ᄋ 0.71 ¾X ㅁ Comparative Example 9 Liquid Crystal 1 1.71 ι ᄋ b · 1.53 C E

¾Λ in Comparative Example 10 PC 30 1 ᄋ ¹ J 0.47 o ΗΛi

 口 Rating 1

 In the compensation films according to Examples 1 to 14 and Comparative Examples 1 to 10, the birefringence difference between the U phase retardation layer and the crab two phase retardation layer and the wavelength dispersion of the birefringence according to the wavelength are confirmed.

 The birefringence in the phase delay layer is measured using ElHpsometry. In-plane retardation for wavelength dispersion calculation is measured using Kobra (0ji Scientific Instrument), where the measurement wavelength ranges from 400 nm to 700 nm.

 The results are shown in Table 5.

 Table 5

 Birefringence Difference in Slow Axis Wavelength Dispersion

Δη @ 450 nm Δη @ 550 nm Δη @ 650 nm ΔΑ (450/550) ΔΑ (650/550) Example .1 0.234 0.202 0.189 1.157 0.935 Example 2 0.204 0.180 0.170 1.132 0.942 Example 3 0.158 0.141 0.134 1.118 0.946 Example 4 0.086 0.078 0.074 1.111 0.948 Example 5 0.236 0.204 0.191 1.156 0.935 Example 6 0.206 0.182 0.172 1.131 0.943 Example 7 0.160 0.144 0.136 1.116 0.946 Example 8 0.236 0.204 0.191 1.156 0.935 Example 9 0.206 0.182 0.172 1.131 0.943 Example 0.160 0.144 0.136 1.116 0.946

10

Example 0.163 0.146 0.138 1.115 0.947

11

Example 0.089 0.080 0.076 1.108 0.949

12

Example 0.158 0.141 0.134 1.118 0.946

13

Example 0.234 0.202 0.189 1.157 0.935

14

Comparative Example 1 -0.030 -0.022 -0.019 1.363 0.875 Comparative Example 2 -0.076 -0.060 -0.055 1.249 0.909 Comparative Example 3 -0.147 -0.124 -0.115 1.186 0.926 Comparative Example 4 0.030 0.022 0.019 1.363 0.875 Comparative Example 5 -0.046 -0.039 -0.036 1.185 0.929 Comparative Example 6 0.118 -0.102 -0.096 1.148 0.937 Comparative Example 7 0.076 0.060 0.055 1.249 0.909 Comparative Example 8 0.046 0.039 0.036 1.185 0.929 Comparative Example 9 —0.072 -0.064 -0.060 1.126 0.943 Comparative Example 0.308 0.272 0.250 1.135 0.920

10

* Δη = Δ¾2-Δη _χ ι

* ΔΑ (450/550) = (Δ η χ2 (450nm) - Δ n xi (450nm)) / (Δ η χ2 (550nm) - Δη χ1 (550ηιτι))

* ΔΑ (650/550) = (Δη _χ2 (650ηπι) -Δη _χ ι (650ηηι)) / (Δη _χ2 (550ηηι)-Δη _χ ι (550ηιη))

(Δη _χ2: birefringence, Δη _χ1 of the slow axis of the second phase delay layers: the birefringence of the slow axis of the first phase retardation layer).

Evaluation 2 In the compensation films according to Examples 1 to 14 and Comparative Examples 1 to 10, the polarizing plate is pasted to the side of the first phase retardation layer such that the polarization axis of the polarizing plate is at an angle of -15 ± 2 degrees with respect to the slow axis of the first phase retardation layer. And arrange | positioning the other reflector, the test film is produced.

 The front reflectance of the test film is evaluated.

 The front reflectance is evaluated using a spectrophotometer (CM-3600d, Koni ca Minol ta Co., Ltd.) while supplying light under conditions of light source D65, 8 degree reflection and 2 degree receiving part. The results are shown in Table 6.

 Table 6

 Frontal reflectance Maximum reflectance (%)

Example 1 1.26 4.36

Example 2 1.28 4.36

Example 3 1.23 4.28

Example 4 1.23 4.55

Example 5 1.26 4.36

Example 6 1.28 4.36

Example 7 1.23 4.28

Example 8 1.32 4.20

Example 9 1.29 4. 19

Example 10 1.27 4.29

Example 11 1.20 4.20

Example 12 1.22 4.37

Example 13 1. 15 3.56

Example 14 1.21 3.66

Comparative Example 1 3.25 5.85

Comparative Example 2 2.84 4.99

Comparative Example 3 2.85 5. 13

Comparative Example 4 2.99 5.32

Comparative Example 5 3.45 6. 12

Comparative Example 6 4.32 6.89 Comparative Example 7 2.86 5.45

Comparative Example 8 3. 11 5.52

Comparative Example 9 3.85 6.28

Comparative Example 10 1.89 5. 11

 In Table 4, the smaller the front reflectivity and the maximum reflectance, the better. Referring to Table 4, the compensation film according to Examples 1 to 14 it can be seen that the front reflectivity and the maximum reflectance is lower than the compensation film according to Comparative Examples 1 to 10. Accordingly, it can be seen that the wavelength dependence and the viewing angle dependence can be reduced by adjusting the birefringence difference and the birefringence wavelength dispersion ratio of the birefringence layer and the birefringence layer in a predetermined range, thereby improving the reflectance. Can be.

 Evaluation 3

 The foldable properties of the compensation films according to Examples 1 to 14 are evaluated.

 The foldable characteristics are performed by using stat ic flexibilty test equipment and 1R Mandrel Bend Testing equipment. The evaluation method is to change the diameter of Mandrel to a small one and observe the film to record the minimum diameter without cracking. For example, record that 2 cracks do not occur at a diameter of 2 mm. Optical deformation is evaluated according to the change of in-plane retardation before and after evaluation at the minimum diameter where no crack occurs. In-plane retardation is measured using a K0BRA instrument (Oj i Instrument).

 The results are shown in Table 7.

 Table 7

 The smallest crack-free diameter in-plane retardation change rate (@ 550nm) Example 1 2mm Onm

Example 2 2 隱 Onm

Example 3 2 mm Onm

Example 4 2 mm Onm

Example 5 3 隱 Onm

Example 6 3 mm Onm

Example 7 3 隱 Onm Example 8 3 mm Onm. Example 9 3 隱 Onm

Example 10 3 mm Onm

Example 11 5 mm Onm

Example 12 3 画 Onm

Example 13 2 mm-Onm

Example 14 2 mm Onm

Referring to Table 7, it can be seen that the compensation films according to Examples 1 to 14 do not have cracks in the flexural test of at least 5 mm diameter, and thus there is no external deformation, and also there is no optical deformation as there is no in-plane phase difference change. Therefore, it can be seen that the compensation films according to Examples 1 to 14 have sufficiently foldable characteristics. Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to the scope of the invention.

[Explanation of code]

 10 ： compensation film 11: huge U phase delay layer

12: second phase retardation layer 13, 15: alignment film

 20: polarizer 30: optical film

 40 ： display panel 400 organic light emitting display panel

410 Base substrate 420 Lower electrode

 430 organic light emitting layer 440 upper electrode

 450 Encapsulation Board 500 Liquid Crystal Display Panel

510 First display panel 520 Second display panel

530 —ι ό ο

Claims

[Claims] [Claim 1] A compensation film for foldable use, comprising a first phase retardation layer containing a polymer, and a second phase retardation layer located on one side of the first phase retardation layer and containing a liquid crystal composition. [Claim 2] In claim 1, the birefringence in the slow axis of the first phase retardation layer and the second phase retardation layer satisfies the following relations 1 to 5: A compensation film for foldable use: [Relationship 1] 0.055 < An _x2 (450nm) - A n _x i(450nm) < 0.300 [Relational Expression 2] 0.050 < Δ η _χ2 (550ηηι) - A n _x i (550 nm) < 0.250 [Relational Expression 3] 0.045 < A n _x2 (650 nm) - Δ η _χ1 (650ηη0 < 0.230 [Relational Expression 4] _{1.00 < ( Δn} ..21 [Relational Expression 5] 0.90 < (Δn _x2 (650nm) _-Δnxi (650nm))/( _Δnx2 (550nm)-Δnxi( _550nm )) < 1. 10 In equations 1 to 5 above, Δ η _χ ι(450ηιη), Δ η _χ1 (550ηηι) and Δ η _χ1 (650ηιη) are the birefringence at the slow axis of the first phase retardation layer for incident light with wavelengths of 450, 550 nm and 650 nm, respectively, and Δ η _χ2 (450ηηι) , A n _x2 (550nm) and _Δηι2 (650ηιη) are the birefringences in the slow axis of the macrophase retardation layer for incident light with wavelengths of 450 nm, 550 nm and 650 nm, respectively. [Claim 3] In paragraph 1, In the slow axis of the first phase delay layer and the second phase delay layer A compensation film for foldable use whose birefringence satisfies the following equation 6: [Relational Expression 6] Δ n _x2 (650nm)- Δ n _xl (650nm)< Δ n _x2 (550nm)- Δ n _xl (550nm)< Δ n _x2 (450nm)-

In equation 6 above, ^Δη _χ1 (450ηπι), Δ η _χ1 (550ηπι) and Δ η _χ1 (650ηηι) are the birefringences in the slow axis of the crab 1 phase retardation layer for incident light with wavelengths of 450 nm, 550 nm and 650 nm, respectively, and Δ η _χ2 ( 450ηηι), _Δηχ2 (550ηηι) and _Δηι2 (650ηιη) are the birefringence in the slow axis of the second phase retardation layer for incident light with wavelengths of 450 nm, 550 nm and 650 nm, respectively. 【Claim 4】 In paragraph 1, The in-plane retardation of the compensation film for incident light of 450nm, 550nm and 650nm wavelengths is a compensation film for foldable use that satisfies the following equation 7 or 8: [Relational Equation 7] R _e0 (450nm) < R _e0 (550nm) < R _e o (650nm) [Relational Expression 8] Reo(450nm)<Reo(550nm) < _e0 (650nm) In equations 7 and 8 above, Reo(450nm), R _e0 (550nm) and R _e0 (650nm) are the in-plane retardation of the compensation film for 450nm, 550nm and 650nm incident light, respectively. [Claim 5] In Port U, The in-plane retardation of the first phase retardation layer for incident light with a wavelength of 550 nm is 220 nm to 320 nm, A compensation film for foldable use, wherein the in-plane retardation of the second phase retardation layer for incident light with a wavelength of 550 nm is llOnm to 160 nm. 【Claim 6】 In Port U, The polymers include polycarbonate, cycloolefin polymer, poly (meth)acrylate, polystyrene, polymaleimide, polyacrylonitrile, Compensation film for foldable use containing polyethylene terephthalate, cellulose, their derivatives, their copolymers, or a combination thereof. 【Claim 7】 In Port U, A compensation film for foldable use, further comprising an alignment film located on one side of the second phase delay layer. 【Claim 8】 In paragraph 1: A compensation film for foldable use, further comprising a reinforcing layer located on one side of the second phase retardation layer and containing a vertically aligned liquid crystal composition. [Claim 9] In paragraph 18, A compensation film for foldable use, further comprising an alignment layer positioned on at least one surface of the two-phase retardation layer and the reinforcement layer. 【Claim 10】 polarizing element, and An optical film comprising a compensation film for foldable use according to any one of paragraphs U to 9. 【Claim 11】 display panel, and A compensation film for foldable use located on one side of the display panel and including a first phase retardation layer containing a polymer and a second phase retardation layer containing a liquid crystal composition. A display device containing a . 【Claim 12】 In paragraph 11, A display device in which the birefringence of the first phase delay layer and the second phase delay layer in the slow axis satisfies the following equations 1 to 5: [Relationship 1] 0.055 < A n _x2 (450nm) - Δη _χ1 (450ηηι) < 0.300 [Relational Expression 2] 0.050 < An _x2 (550nm) - Δη _χ1 (550ηπι) < 0.250 [Relational Expression 3] 0.045 < Δη _χ2 (650ηιη) - An _xl (650nm) < 0.230 [Relational Expression 4] 1.00 < ( _Δnx2 (450nm) - _Δnxi (450nm)) / ( _Δnx2 (550nm) - _Δnxi (550nm)) < 1.21 [Relational Expression 5] 0.90 < (Δ n _x2 (650 nm) - Δ n _{x !} (650 nm) ) / (Δ n _x2 (550 nm) - Δ n _x i (550 nm) ) < l.io In equations 1 to 5 above, _{A n _ _} Δη _χ2 (550ηπι) and Δη _χ2 (650ηηι) are the birefringence in the slow axis of the second phase retardation layer for incident light with wavelengths of 450 nm, 550 nm and 650 nm, respectively. 【Claim 13】 In paragraph 11: A display device in which the birefringence of the first phase retardation layer and the second phase retardation layer in the slow axis satisfies the following equation 6: [Relational Expression 6] ^Δη _χ2 ( ^650η πι)- ^Δη _χ ι(650ηπι) < Δη _χ2 (550ηηι)- An _xl (550nm) < Δη _χ2 (450ηηι)- An _xl (450nm) In equation 6 above, _{An _ _ _ _} (550nm) and Z _n [Claim 14] In paragraph 11, In-plane of the compensation film for incident light of 450nm, 550nm and 650nm wavelengths The phase difference is a display device that satisfies the following equation 7 or 8: [Relational Equation 7] R _e0 (450nm) <Re ₀ (550nm)<R _e o (650nm) [Relational Expression 8] R _e0 (450nm)<R _e o(550nm) < _e0 (650nm) In equation 7 or 8 above, R _e0 (450 nm), R _e0 (550 nm) and R _e0 (650 nm) are the in-plane retardation of the compensation film for 450 nm, 550 nm and 650 nm incident light, respectively. 【Claim 15】 In paragraph 11, The in-plane phase difference of the first phase retardation layer for incident light with a wavelength of 550 nm is 220 nm to 320 nm, A display device wherein the in-plane retardation of the second phase retardation layer for incident light with a wavelength of 550 nm is 1 Onm to 160 nm. 【Claim 16】 In paragraph 11, The polymer includes polycarbonate, cycloolefin polymer, poly (meth)acrylate, polystyrene, polymaleimide, polyacrylonitrile, polyethylene terephthalate, sallos, derivatives thereof, copolymers thereof, or combinations thereof. Including display device. 【Claim 17】 In paragraph 11: The compensation film for the foldable display device further includes an alignment layer located on one side of the crab 2 phase delay layer. 【Claim 18】 In paragraph 11, The compensation film for the foldable display device further includes a reinforcement layer located on one side of the second phase delay layer and including a vertically aligned liquid crystal composition. 【Claim 19】 In paragraph 18: The compensation film for the foldable display device further includes an alignment film located on one surface of at least one of the second phase delay layer and the reinforcing material. 【Claim 20】 In paragraph 11, A display device further comprising a polarizing element located on one side of the compensation film for the foldable purpose.