KR100605617B1 - Display device - Google Patents

Abstract

The present invention provides a liquid crystal panel having a light guide plate having a light source, a plurality of light transmissive dot pixels and a black mask partitioning the dot pixels, and a plurality of optical patterns linearly arranged at a predetermined pitch. A display device having an optical film interposed therebetween, wherein the pixel pitch (P1) of the liquid crystal panel and the optical pattern pitch (P2) of the optical film,

(P1-Black Mask) / P2 = N + x

Where P1 is the sum of the length of the long direction of the dot pixel and the black mask on one side of the long direction of the dot pixel, and N is an integer, which is obtained when the P1-black mask is divided by the optical pattern pitch P2. Quotient, x is a balance of the optical pattern pitch P2), and x has a value of 0 ± 0.15.

This provides a display device that can prevent moire and at the same time simplify the manufacturing process to improve productivity.

Display, LCD, Liquid Crystal, Panel, Pixel, Optical Pattern, Pitch, Moire, Strip Pattern

Description

Display device

1 is a simplified configuration diagram of a conventional display device;

2 is an exploded perspective view of the panel device of FIG. 1;

3 and 4 are views and graphs showing the direction and luminance of light emitted from the light guide plate of FIG. 1;

5 and 6 are views and graphs showing the direction and brightness of light emitted from the diffusion film of FIG.

7 to 9 are views and graphs showing the direction and brightness of light incident to the prism film and light emitted;

10 is a photograph of a strip pattern phenomenon of the prism film observed from the top of the prism film of FIG.

11 is a plan view showing an optical coupling state of the prism film and the liquid crystal panel of FIG.

12 and 13 is a view showing the configuration of another conventional display device and the optical coupling state of the optical film and the liquid crystal panel,

14 is a partial cross-sectional view of an optical film conventionally applied to another display device;

15 is a simplified configuration diagram of a display device according to the present invention;

16 is an exploded perspective view of the panel device of FIG. 15;

17 is a cross-sectional view for explaining an optical coupling state between the optical film and the liquid crystal panel of FIG. 15;

FIG. 18 is a graph for explaining a pitch relationship between a pixel pitch and an optical pattern of the liquid crystal panel of FIG. 15;

19 to 21 are graphs for explaining the optical uniformity according to the pitch relationship between the pixel pitch and the optical pattern of the liquid crystal panel of FIG.

22 and 23 are optical film cross-sectional view for explaining the optical pattern structure of the display device according to the present invention;

24 is a graph showing a change in luminance according to the optical pattern structure of the display device according to the present invention;

25 to 28 are cross-sectional views of an optical film showing another example of the optical pattern structure of the display device according to the present invention;

29 to 32 are partial cross-sectional views showing a liquid crystal panel and an optical film installation area of a display device according to another embodiment of the present invention.

* Explanation of symbols for the main parts of the drawings

10: backlight unit 11: light source

13: light guide plate 20: optical film

21: optical pattern 30: panel element

31 liquid crystal panel 37 dot pixel

39: black mask

The present invention relates to an optical film and a display device having the same, and more particularly, to an optical film and a display device having the same, which can prevent the moire phenomenon.

As shown in FIG. 1, a general configuration of a liquid crystal display (LCD) device widely used in a mobile phone, a notebook computer, a monitor, a TV, and the like is provided in front of a backlight unit 110 and a backlight unit. The panel device 130 displays an image by using light transmitted from the backlight unit.

The backlight unit is provided between the light guide plate 113 having the light source 111 and the light guide plate 113 and the panel element 130, and a series of refraction, condensing, and diffusion of light from the light guide plate 113 to the panel element 130. It has optical films 120 to induce an optical action of the image to determine the image display performance, such as the viewing angle, brightness, sharpness of the image displayed on the panel element 130. Representative optical film 120 may be a diffusion film 121 for diffusing light toward the panel device 130, prism films (123, 150) for refracting and condensing light toward the panel device 130, and the like.

The backlight unit includes a direct backlight unit in which the position of the light source 111 is disposed in the lower region of the light guide plate 113, and a side dimming method in which the position of the light source 111 is disposed in one side region of the light guide plate 113. Type backlight unit, which is recently used in the backlight unit of the side dimming method in order to achieve a slim and compact display device 101.

As shown in FIG. 2, the panel device 130 includes a pair of polarizing plates 133 and a liquid crystal panel 131 disposed between both polarizing plates 133. The liquid crystal panel 131 has an arrangement of a number of pixels 135, and each pixel 135 has three R / G / B light transmissive dot pixels 137, as shown in FIG. It consists of a non-transmissive black mask (139) which partitions each dot pixel (137).

In the display device 101 having the above configuration, the light generated from the light source 111 of the backlight unit is diffused from the diffusion film 121 through the light guide plate 113, and then condensed and refracted by the prism films 123 and 150. When light is transmitted to 130, a predetermined image is displayed on the surface of the liquid crystal panel 131 by selective R / G / B transmission / non-transmission of each pixel 135 in the liquid crystal panel 131 to which an electric field is applied.

However, in the display apparatus 101 using such a backlight unit, a strip pattern phenomenon due to incident light is generated in the prism film 123 of the backlight unit, and the strip pattern arrangement of the liquid crystal panel 131 is performed. There is a problem in that moire is generated by optical coupling with the pixel 135 array.

First, the cause of the strip pattern phenomenon in the prism film 123 will be described.

As shown in FIG. 3, most of the light generated by the light source 111 of the backlight unit is incident on the light incident part 113a (the left side of the light guide plate 113 in the drawing) of the light guide plate 113, and thus the opposite light guide part 113b. 3) is diffused with an upward exit angle (hereinafter referred to as "right upward exit angle θ ₁ ") toward the light guide portion 113b while proceeding toward the direction (right side of the light guide plate 113 in the drawing). Incident. (Here, the directions of the light incident portion 113a and the light facing portion 113b may be changed.)

And, when the light incident on the diffusion film 121 is emitted from the diffusion film 121, as shown in Figure 5, the right upward emission angle refracted by a predetermined angle in the vertical direction with respect to the plate surface of the diffusion film 121 (θ ₂ ) is emitted, and the emitted light having an upward exit angle θ ₂ is incident to the prism film 123 again.

The light incident on the prism film 123 is refracted upward by a predetermined angle by the medium refractive index of the prism film 123 while passing through the incident surface 123a of the prism film 123, It is still transmitted to the left refractive pattern surface 125 and the right refractive pattern surface 126 on the triangular cross section formed on the emission surface 123b of the prism film 123 with the right upward emission angle θ ₃ .

In this case, as shown in FIG. 8, the light directed toward the left refractive pattern surface 125 among the light transmitted to the left refractive pattern surface 125 and the right refractive pattern surface 126 with the right upward emission angle θ ₃ . Is totally reflected with the total reflection critical angle with respect to the left refractive pattern surface 125 and is transmitted to the right refractive pattern surface 126. Then, by forming the lost light refracted in the substantially right horizontal direction on the right refractive pattern surface 126, when viewed in the vertical upper region of the prism film 123, the region of the left refractive pattern surface 125 is relatively low luminance Is confirmed.

On the other hand, the light directed toward the right refractive pattern surface 126 of the light transmitted to the left refractive pattern surface 125 and the right refractive pattern surface 126 with the right upward emission angle θ ₃ is the right refractive pattern surface 126. Since the angle of incidence in the direction intersecting at an angle smaller than the total reflection critical angle with respect to, it is formed as effective light that is refracted upward in a substantially vertical direction on the right refractive pattern surface 126. When the light refracted upward is viewed from the upper region of the prism film 123 in the vertical direction, the region of the right refractive pattern surface 126 is observed with relatively high luminance.

4, 6, and 9 show data obtained by measuring a view angle of the light emitted from the light guide plate 113 through the prism film 123 in the general conventional side dimming type backlight unit.

Here, the center of the circular contour graph of each drawing represents a viewing angle in a direction orthogonal to 90 degrees with respect to the horizontal plane of the light guide plate 113, the diffusion film 121, and the prism film 123, respectively. Hereinafter, for convenience of description, the central viewing angle of the circular contour graph is defined as "0 degree". In addition, in the drawings, the lower portion of the circular contour graph corresponds to the light incidence portion 113a side of the light guide plate 113, and the left region of the light guide plate of FIG. 3, the left region of the diffuser film of FIG. 5, and the left region of FIG. 8. The upper portion of the circular contour graph is a region corresponding to the light guide portion 113b side of the light guide plate 113 and shows a right region of the light guide plate of FIG. 3, a right region of the diffusion film of FIG. 5, and a right region of FIG. 8.

4 illustrates the luminance according to the viewing angle at the upper portion of the light guide plate 113, and FIG. 6 illustrates the luminance according to the viewing angle in the state where the diffusion film 121 is disposed at the upper portion of the light guide plate 113. 9 illustrates luminance according to a viewing angle in a state where the diffusion film 121 and the prism film 123 are sequentially disposed on the light guide plate 113.

As can be seen from these figures, it can be seen that the light emitted from the light guide plate 113 has a high luminance at the light guide portion 113b side (right side of FIGS. 3, 5, and 8), and the diffusion film 121 The brightness of the light emitted while arranging the prism film 123 is increased in the vertical direction between the light guide plate 113, the diffusion film 121, and the prism film 123.

That is, as in the light guide plate emitting light which is emitted from 113 and the diffusion film 121 and the prism film 123, right upward exit angle (θ ₁ ~ θ ₃₎ will be found in the Figures 3 and 4, θ ₁ When the luminance according to the viewing angle is measured on the upper part of the light guide plate 113, the luminance is high in the region of about 70 ° to 90 ° with respect to the central viewing angle of 0 ° orthogonal to the horizontal plane of the light guide plate 113. . 5 and 6, when the luminance according to the viewing angle at the top of the diffusion film 121 is measured by θ ₂ , a center viewing angle of 0 ° orthogonal to the horizontal plane of the plate surface of the diffusion film 121 is measured. It can be seen that the luminance is high in the range of about 30 ° to 50 °.

In addition, as shown in FIGS. 8 and 9, when the luminance according to the viewing angle is measured at the top of the prism film 123 by θ ₃ , a center viewing angle of 0 ° orthogonal to the horizontal plane of the plate surface of the prism film 123 is measured. It can be seen that the luminance is high in the range of about 5 ° ~ 12 °.

As described above, the light incident on the prism film 123 is relatively low luminance at the left refractive pattern surface 125 and the right refractive pattern surface 126 of the prism film 123 as described above. It causes a nonuniformity in luminance emitted by the lost light and relatively high luminance effective light.

FIG. 10 is a photograph of light emitted from an upper region orthogonal to 90 degrees (center viewing angle 0 °) with respect to the plate surface of the prism film 123 under a microscope.

In this figure, the dark part is observed as the relatively low luminance lost light in which the light totally reflected from the left refractive pattern surface 125 of the prism film 123 is refracted in the right direction, and the bright part is the right side of the prism film 123. The light refracted upward in the substantially vertical direction at the refraction pattern surface 126 is observed as the effective light of relatively high luminance.

As a result, a strip pattern phenomenon periodically occurs due to unevenness of luminance in which a low luminance region and a high luminance region alternately appear over the entire area of the prism film 123.

Meanwhile, the causes of moire phenomena due to the optical coupling between the prism film 123 and the pixel 135 array of the panel element 130 will be described below.

As shown in FIG. 11, when the panel element 130 is disposed on the prism film 123 where the strip pattern phenomenon occurs, the light-transmitting dot pixel 137 region of the pixel 135 of the liquid crystal panel 131 is formed. The non-transparent black mask 139 region is irregularly overlapped with the strip pattern of the prism film 123.

Then, as shown in the display portion "a" in the drawing, in the transparent dot pixel 137 in one region, a portion where the bright portions of the strip pattern overlap in a relatively large area is generated, and in another region, such as the display portion "b". In the light transmissive dot pixel 137, a portion where the dark portion of the strip pattern overlaps in a relatively large area occurs.

As a result, a difference in brightness between the pixels 135 is generated, and when the whole of the liquid crystal panel 131 is observed while the brightness difference between the pixels 135 is large, a moire phenomenon occurs. This moire phenomenon has a problem of being a fatal performance defect of the display apparatus 101.

In order to solve the problem of the moire phenomenon of the display device, US Patent No. 5,280,371 discloses a "directional diffuser for liquid crystal display", US Patent No. 5,919,551 discloses an "optical film of irregular pitch structure".

The former "directional directional diffuser for liquid crystal display", as shown in Figure 12, by arranging two lens array film 205 between the backlight unit 201 and the liquid crystal panel 203 to ensure uniform brightness within the viewing angle It was.

In addition, as shown in FIG. 13, the linear arrangement of the refractive patterns 210 of at least one of the two lens array films 205 is misaligned with respect to the pixel axis of the liquid crystal panel 203. By having the predetermined angle α, the moire phenomenon is prevented from occurring when the lens array film 205 and the liquid crystal panel 203 are optically combined.

On the other hand, the latter "optical film of an irregular pitch structure", as shown in Figure 14, the refractive pattern 301 on the triangular cross-section formed on the surface of the optical film 300 is irregular pitch interval (P _a , P _b ) In this case, it is intended to prevent irregular moire while inducing irregular condensation of light to ensure uniformity of luminance within a viewing angle.

However, in such conventional US 5,280,371 "directional diffuser for liquid crystal display" and US 5,919,551 "optical film of irregular pitch structure", the lens array linear arrangement of the lens array shape and mis-alignment, and irregular pitch structure The optical molding of has been relatively difficult. As a result, a problem arises in that the productivity of the optical film and the display device is lowered.

In addition, US 5,280,371 "Directional diffuser for liquid crystal display" is a simple method, but the crossover angle must be different for each LC module, there is a disadvantage that the optical film must be accurately cut and assembled at a predetermined angle, US 5,919,551 In the case of the "optical film having an irregular pitch structure," it is difficult to manufacture a plurality of optical patterns with irregular pitches considering that the size of the optical pattern in a general optical film is a unit of μm.

Accordingly, it is an object of the present invention to provide a display device that can prevent moire phenomena and at the same time improve the productivity by simplifying the manufacturing process.

According to the present invention, there is provided a liquid crystal panel having a light guide plate having a light source, a plurality of light transmissive dot pixels and a black mask partitioning the dot pixels, and a plurality of optical patterns linearly arranged at a predetermined pitch. In the display device having an optical film interposed between the light guide plate and the liquid crystal panel,

The pixel pitch P1 of the liquid crystal panel and the optical pattern pitch P2 of the optical film are

(P1-Black Mask) / P2 = N + x

Where P1 is the sum of the length of the long direction of the dot pixel and the black mask on one side of the long direction of the dot pixel, and N is an integer, which is obtained when the P1-black mask is divided by the optical pattern pitch P2. Quotient, x is a balance of the optical pattern pitch P2), and x is a value of 0 ± 0.15.

Wherein the optical pattern has a pair of light incidence side pattern surfaces and a light incidence side pattern surface formed at predetermined inclination angles (θ) on both sides of a virtual vertical axis perpendicular to the horizontal plane of the optical film; Regarding incident light in which at least a portion of each of the pattern surfaces is incident from the light guide plate at a predetermined angle θ ₄ ,

Θ ₄ = θ + θ ₃ ,

이며,remind

Is,

이며,Θ _c =

Is,

(Where θ ₂ is the angle of incidence of incident light incident on the optical film, the angle of inclination with respect to the horizontal plane of the optical film, n is the refractive index of the medium of the optical film, θ ₃ is the virtual light of the outgoing light directed toward the light incident part side pattern surface) An angle with respect to the vertical axis of θ _c , the total reflection critical angle of the light incident part side pattern surface with respect to the emitted light of θ ₃ ),

Θ is relative to θ ₄ and θ _c

0 <θ ₄ <θ _c

It is preferable to have the inclination angle θ that satisfies the following condition.

In addition, it is effective that the optical pattern has a triangular cross-sectional shape.

At this time, the inclination angle of the triangular cross section of the optical pattern is more preferably 41 to 45 degrees.

Alternatively, the triangular cross-sectional shape is more effectively an isosceles triangle.

On the other hand, when the inclination angle is 41 degrees or less, it is preferable that a brightness enhancing film is provided on the optical film.

Furthermore, the optical pattern is θ _4, which is formed of a polyhedron with the side the mouth portion side pattern which has at least two inclination angles, at least one angle of inclination of the inclination angle satisfies the condition of 0 <θ ₄ <θ _c It is effective to exist.

Alternatively, the optical pattern is more preferably formed of a polyhedron having both at least two inclined angles of the pattern surfaces.

In this case, it is more effective that the at least two or more inclination angle boundary regions are formed in a curved section.

On the other hand, it is preferable that light diffusing particles are distributed in the optical film.

Alternatively, it is effective that the light diffusion film is provided on the optical film.

In addition, the light scattering surface is preferably formed on at least one side of the liquid crystal panel.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

15 is a perspective view showing a simplified configuration of a display device according to the present invention, Figure 16 is an exploded perspective view of the liquid crystal panel 31 of FIG. As shown in these drawings, the display device 1 according to the present invention is transmitted from the backlight unit 10 and the backlight unit 10 in front of the backlight unit 10 like the conventional display apparatus 101 described above. It is composed of a panel element 30 for displaying an image by using the light.

The backlight unit 10 is provided between the light guide plate 13 having the side light source 11 and the light guide plate 13 and the panel element 30 to diffuse light to diffuse light from the light guide plate 13 toward the panel element 30. The film 29 and the optical film 20 for refracting and condensing light.

The light guide plate 13 has substantially the same structure as the light guide plate 13 used for the backlight unit 10 of the general side dimming method. The optical film 20 has a structure in which a plurality of optical patterns 21 for refracting and condensing light in an emission direction on at least one side thereof are linearly arranged with a predetermined pitch P2. Here, the cross-sectional shape of the optical pattern 21 may be formed in various shapes such as a semi-circular cross section including a triangular cross-sectional shape, a partial arc cross section.

The panel element 30 includes a pair of polarizing plates 33 and a liquid crystal panel 31 disposed between both polarizing plates 33. The liquid crystal panel 31 has an arrangement of a plurality of pixels 35 (Pixel), each pixel 35 is a dot pixel 37 of three light transmission regions of R / G / B, and each dot pixel 37 It consists of a non-transmissive black mask 39 (Black mask) for partitioning.

On the other hand, in the display device 1 according to the present invention, the optical film 20 and the liquid crystal panel 31 are coupled to each other with an optical coupling relationship which can minimize the moire phenomenon.

This optical coupling relationship is defined by Fig. 17 and the following Equation-1.

(LCD pixel pitch (P1)-black mask) / optical pattern pitch of optical film (P2) = N + x (Equation-1)

Here, the pixel pitch P1 is the sum of the length of the long direction of the dot pixel 37 in the light transmission region and the width of the black mask on one side of the long direction of the dot pixel 37.

N is an integer and is a quotient obtained by dividing (P1-black mask) by the optical pattern pitch (P2),

x is the remainder of the optical pattern pitch P2. At this time, it has a value of x = 0 ± 0.15.

According to Equation-1, the pitch P2 of the optical pattern 21 of the optical film 20 when the x value satisfies a condition near 0, that is, within the longitudinal length of the dot pixel 37 which is a light transmissive region. When is close to an integer number, it appears that no moire is identified.

This can be seen in the graph of FIG. 18 is an example of a general liquid crystal panel, while the pixel pitch P1 is 209 μm, and the optical film 20 having the pitch P2 of the optical pattern 21 between 20 μm and 30 μm is mutually optically coupled. It is a graph that derives x value that can be minimized.

As shown in this graph, it can be seen that when the x value approaches 0, the moire cycle is formed indefinitely. If the moire cycle is formed to infinity, the moire cycle becomes impossible to identify with the human eye, so the moire is not actually identified.

On the contrary, if the x value is out of the range of 0 ± 0.15, it can be seen that the moire cycle is increased. If the moire cycle is large, the moire cycle is visually confirmed by the human eye, resulting in a fatal defect of the display device.

Here, the x value is 0 ± 0.15, and the moire cycle is formed at infinity and is not identified by the human eye. The uniformity of the light emitted from the dot pixels 37, which are a plurality of light transmitting regions forming the pixels 35, is determined. As formed uniformly, this provides the effect of improving the light uniformity of the display device.

For example, when the pixel pitch P1 of the liquid crystal panel is 209 μm, the black mask is 22 μm, and the long length of the dot pixel 37 is 187 μm, the x value according to the pitch P2 of the optical pattern 21 is derived. Is shown graphically in FIG. 19. As can be seen from this graph, the difference in the outgoing light, i.e., the light quantity ratio, between each dot pixel is formed at the pitch P2 of the optical pattern 21 whose x value corresponds to 0 ± 0.15, whereby each dot pixel of the liquid crystal panel is formed. It can be seen that the light uniformity of the liver becomes constant.

FIG. 20 is a graph measuring light intensity distribution of a display apparatus when an optical film having a pitch P2 of 20.8 μm in an optical pattern corresponding to a region having a small light ratio in the graph of FIG. 19 is used. It can be seen that the distribution of. This improves the quality of the display device.

On the other hand, FIG. 21 is a graph measuring the light amount distribution of the display device when the optical film having the pitch P2 of the optical pattern corresponding to the region having a large light quantity ratio in the graph of FIG. 19 is 21.9 μm. It can be seen that the distribution of the amount of light in the region is formed very uniformly. This leads to deterioration of the display device.

By using the relationship between Equation-1 and the light quantity ratio, while preventing the moire during the optical coupling of the liquid crystal panels of the pixel pitch (P1) 150μm ~ 300μm and the optical film 20 having an arbitrary number of optical patterns 21 The pitch P2 of the optical pattern 21, which may be uniformly distributed, may be derived as shown in Table 1 below.

Liquid crystal panel pixel pitch P1 (μm) Black mask (μm) Optical pattern pitch P2 (μm) of optical film 150 30 12, 13.3, 17.1, 20, 24, 30 200 30 17, 18.9, 21.3, 24.3, 28.3, 34, 42.5 250 30 22, 24.4, 27.5, 31.4, 36.7, 44, 55 300 30 27, 30, 33.8, 38.6, 45, 54, 67.5

TABLE-1

On the other hand, the display device 1 according to the present invention reduces the strip pattern phenomenon in the optical film 20, including the optical coupling relationship between the liquid crystal panel 31 and the optical film 20 described above, thereby minimizing the moire phenomenon can do.

The optical pattern 21 structure of the optical film 20 which can reduce the strip pattern phenomenon is formed on both sides of the virtual vertical axis S orthogonal to the horizontal plane of the optical film 20, as shown in FIG. Both sides of the pair of pattern surfaces are formed to have an angle at which side incident light transmitted from the light incidence portion 13a of the light guide plate 13 can be refracted into effective light in the vertical direction.

The case where the light source 11 is arrange | positioned at the left side of the light guide plate 13 (light source 11 may be arrange | positioned at any one side of the light guide plate 13) is demonstrated as an example.

As the light incident on the optical film 20 passes through the incident surface 27a of the optical film 20 as shown in FIG. 23, the light is incident by right angles by the medium refractive index of the optical film 20. The light is refracted by the upward emission angle θ ₃ and transferred to the left and right pattern surfaces 23 and 25 of the optical pattern 21 formed on the emission surface 27b of the optical film 20.

Among them, the light directed toward the right pattern surface 25 becomes an incidence angle in the direction crossing the right pattern surface 25, and thus is refracted upward in the almost vertical direction on the right pattern surface 25. The upwardly refracted light is observed as effective light having a relatively high brightness when viewed in the vertical upper region of the optical film.

On the other hand, in order for the light toward the left pattern surface 23 to be refracted upward from the left pattern surface 23, when the incident angle of light incident on the left pattern surface 23 is incident outside the total reflection critical angle, the light may be refracted and transmitted without being totally reflected.

The relationship between the total reflection critical angle and the incident angle of light is confirmed by FIG. 23 and the following equations.

(식-2)

(Equation-2)

Here, θ ₂ is the angle of incidence of the incident light incident on the optical film 20, the angle of inclination with respect to the horizontal plane of the optical film, n is the refractive index of the medium of the optical film, θ ₃ is the outgoing light toward the light incident part side pattern surface. Angle with respect to the virtual vertical axis.

When this is converted into the incident angle θ ₄ with respect to the left pattern surface 23 of the optical pattern 21,

θ ₄ = θ + θ ₃ (Equation-3)

Becomes

The total reflection critical angle θ _c at the left pattern surface 23 of the optical pattern 21 is

(식-4)θ _c =

(Equation-4)

Is calculated.

By such formula-2 to formula-4,

θ ₄ ≥θ _c (Equation-5)

In one case, when the light incident on the left pattern surface 23 is totally reflected and confirmed in the upper region of the vertical direction of the optical film 20, it can be seen that the light is relatively lost. In this case, the strip pattern is caused by a sharp difference in luminance from the emitted light from the right pattern surface 25 observed as the effective light.

Meanwhile,

0 <θ ₄ <θ _c (Equation-6)

In one case, when the light incident on the left pattern surface 23 is refracted and transmitted through the upper region of the optical film 20, the light incident to the left pattern surface 23 is confirmed to be relatively high luminance effective light. In this case, the luminance difference from the emitted light from the right pattern surface 25 observed as the effective light is reduced, so that the strip pattern phenomenon can be minimized.

Therefore, if the angle and structure between both pattern planes of the optical pattern 21 are set to include a large incidence angle θ ₄ satisfying 0 <θ ₄ <θ _c in Equation-6 by decreasing the inclination angle θ, the strip pattern phenomenon Moire can be prevented by minimizing the occurrence.

In order to prove the minimization of the moire phenomenon by the suppression of the strip pattern phenomenon, as shown in Table 2, the inclination angle of the optical pattern 21 on the triangular cross sections of the optical films A, B, C, D, and E is 46.5 to 37.5 degrees. While changing, the result of observing the occurrence of the moire phenomenon in the liquid crystal panel 31 was shown.

Tilt angle 46.5 42.7 41.3 39 37.5 A 2 2 One One 0 B One 0 0 0 0 C 3 2 2 One 0 D 0 0 0 0 0 E 0 0 0 0 0

TABLE-2

(Here, when the moire intensity is expressed numerically, strong = 3.medium = 2, about = 1, nothing = 0)

As can be seen in Table 2, in the liquid crystal panel 31 which is optically coupled to the optical films A, B, and C, where the strip pattern was generated by the inclination angle of 46.5 degrees, the inclination angles of the optical films A, B, and C were As the light decreases from 46.5 degrees to 37.5 degrees, that is, the amount of light satisfying the condition of 0 <θ ₄ <θ _c of Equation-6 increases, the moire phenomenon decreases.

In addition, in the liquid crystal panel 31 which is optically coupled to the optical films D and E where the strip pattern did not occur at an inclination angle of 46.5 degrees, the inclination angles of the optical films D and E were varied from 46.5 degrees to 37.5 degrees. By satisfaction, it was confirmed that the moire phenomenon still does not occur.

Thereby, the light is refracted and transmitted toward the liquid crystal panel 31 at least on the right pattern surface 25, so that the inclination angle θ ₄ of the left pattern surface 23 has an angle satisfying the condition of Equation-6. It is proved that by setting the angles and structures between both pattern surfaces of (21), the strip pattern phenomenon can be suppressed while the moire phenomenon in the liquid crystal panel 31 can be reduced.

In this case, the vertex angle of the optical pattern 21 may be set to 98 degrees or more (inclined angle 41 degrees or less), but when the vertex angle of the optical pattern 21 is 98 degrees or more (angle 41 degrees or less), the graph of FIG. As can be seen, there may be a problem that the brightness is lowered. Of course, when the inclination angle of the optical pattern 21 is 41 degrees or less (vertical angle 98 degrees or more), an optical film for improving brightness, such as a reflective polarizing film without a separate microstructure, is added to the upper region of the optical film 20. By this, the luminance can be improved.

25 to 28 are partial cross-sectional views showing other embodiments of the optical film used in the display device according to the present invention.

First, as shown in FIG. 25, the optical pattern 21 of the optical film 20 has at least two or more inclination angles of one side of the pattern surface (left side in the drawing) facing the light incident portion 13a side of the light guide plate 13. It may have a polyhedral shape having a shape, and the pattern surface (right side in the drawing) facing the light guide portion 13b side of the light guide plate 13 may have a linear inclination angle.

At this time, the inclination angle of at least one of the two or more inclined surfaces of the left pattern surface 23 satisfies the condition of Equation-6 to refract light incident thereto, and the right pattern surface 25 also receives the incident light. By refracting through 31, the strip pattern phenomenon can be suppressed and moire can be prevented.

Of course, both the left and right pattern surfaces 23 and 25 may be formed of a polyhedron having at least two or more inclination angles that satisfy the conditions capable of refracting and transmitting light.

And, as shown in Figure 27, the optical pattern 21 of the optical film 20 is at least two or more inclination angle of the pattern surface (left side in the drawing) of one side toward the light incident portion 13a side of the light guide plate 13 Each inclination angle boundary region has a shape of a polyhedron having a polyhedron shape, and a pattern surface (right side in the drawing) facing the light guide portion 13b side of the light guide plate 13 has a linear inclination angle. Can be.

At this time, at least one of the inclination angles or curved sections of the two or more inclined surfaces of the left pattern surface 23 is transmitted through the light satisfies the condition of Equation-6, and the right pattern surface 25 is also incident light By refracting the light toward the liquid crystal panel 31, the strip pattern phenomenon can be suppressed and moire can be prevented.

Also in this case, as shown in Fig. 28, both the left and right pattern surfaces 23 and 25 each have at least two or more inclination angles and curved sections 41 in the inclination angle boundary region that satisfy the conditions capable of refracting and transmitting light. It may be formed into a polyhedron.

On the other hand, the display device 1 according to the present invention may include a configuration for compensating for the occurrence of a decrease in luminance or a slight strip pattern and moire phenomenon due to the processing error or molding error of the optical film 20.

As shown in FIG. 29, when the optical film 20 is formed, the optical film 20 contains the light diffusing particles 50 to diffuse and scatter light, thereby improving the luminance lowered in the error range, and having a slight strip. It is also possible to reduce the pattern to prevent moire.

In this case, the light diffusion particles 50 may be any one of acrylic particles, styrene particles, silicon particles, synthetic silica, grass beads, and diamond as transparent particles. In addition, any one of titanium oxide, zinc oxide, barium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide, and clay may be used as the white particles.

And, as shown in Figure 30, by installing a separate light diffusing film 60 for diffusing and scattering light on the optical film 20, by reducing the slight strip pattern while improving the luminance reduced in the error range Moire phenomenon can be prevented.

31 and 32, the light scattering agent 70 is disposed on at least one side of the liquid crystal panel 31. By mixing with a pressure-sensitive adhesive or forming a diffusion and scattering structure 80 such as an embossing structure to increase the haze, the moire phenomenon can be prevented by lowering a slight strip pattern while improving luminance lowered in the error range. have.

As described above, the display apparatus according to the present invention optically combines the relationship between the pixel pitch P1 of the liquid crystal panel and the optical pattern pitch P2 of the optical film to satisfy Equation-1, so that the strip pattern generated in the optical film is reduced. Arranged regularly within the pixel of the liquid crystal panel prevents moire and improves light uniformity.

In addition, by setting the structure and the inclination angle of the optical pattern of the optical film to a structure and an angle that can reduce the luminance difference on the left and right pattern planes on both sides, it is possible to more effectively prevent the moire phenomenon in the liquid crystal panel by suppressing the strip pattern. Can be.

In addition, the optical pattern pitch P2 of the optical film with respect to the pixel pitch of the liquid crystal panel satisfies the same conditions as the relational expression described above, and since the moire phenomenon can be easily prevented, molding of the optical film and the liquid crystal panel Optical coupling with and the like. Therefore, productivity can be improved by standardizing by adjusting the pitch and the inclination angle of the optical film without a complicated assembly process such as crossing the optical film with the panel at a predetermined angle as in the conventional method.

As described above, according to the present invention, there is provided a display device capable of preventing moire phenomenon and improving productivity by simplifying the manufacturing process.

Claims (12)

A liquid crystal panel having a light guide plate having a light source, a plurality of light transmissive dot pixels and a black mask partitioning the dot pixels, and a plurality of optical patterns linearly arranged at a predetermined pitch, and interposed between the light guide plate and the liquid crystal panel. In a display device having an optical film, The pixel pitch P1 of the liquid crystal panel and the optical pattern pitch P2 of the optical film are (P1-Black Mask) / P2 = N + x Where P1 is the sum of the length of the long direction of the dot pixel and the black mask on one side of the long direction of the dot pixel, and N is an integer, which is obtained when the P1-black mask is divided by the optical pattern pitch P2. Quotient, x is the remainder of the optical pattern pitch P2), And x has a value of 0 ± 0.15. The method of claim 1, The optical pattern has a pair of light incidence side pattern surfaces and a light incidence side pattern surface formed at predetermined inclination angles (θ) on both sides of an imaginary vertical axis perpendicular to the horizontal plane of the optical film; Regarding incident light in which at least a portion of each of the pattern surfaces is incident from the light guide plate at a predetermined angle θ ₄ , Θ ₄ = θ + θ ₃ , remind

Is, θ _c =

(Where θ ₂ is the angle of incidence of incident light incident on the optical film, the angle of inclination with respect to the horizontal plane of the optical film, n is the refractive index of the medium of the optical film, θ ₃ is the virtual light of the outgoing light directed toward the light incident part side pattern surface) An angle with respect to the vertical axis of θ _c , the total reflection critical angle of the light incident part side pattern surface with respect to the emitted light of θ ₃ ), Θ is relative to θ ₄ and θ _c 0 <θ ₄ <θ _c And a tilt angle θ that satisfies the condition. The method according to claim 1 or 2, And the optical pattern has a triangular cross-sectional shape. The method of claim 3, Triangular cross section inclination angle of the optical pattern is a display device, characterized in that 41 to 45 degrees. The method of claim 4, wherein The triangular cross-sectional shape is an isosceles triangle. The method of claim 3, When the inclination angle is 41 degrees or less, the display device, characterized in that the brightness enhancement film is provided on the optical film. The method of claim 2, The optical pattern is formed of a polyhedron having the surface of the mouth portion side pattern at least two inclination angles, to the at least one angle of inclination of the inclination angle is θ ₄ exists that satisfies the above condition 0 <θ ₄ <θ _c Display device characterized in that. The method of claim 2, The optical pattern is a display device, characterized in that the pattern surface is formed of a polyhedron each having at least two or more inclination angle. The method according to claim 7 or 8, And the at least two inclination angle boundary regions are formed in a curved section. The method of claim 3, Display apparatus, characterized in that the light diffusion particles are distributed in the optical film. The method of claim 3, Display device, characterized in that the light diffusion film is provided on the optical film. The method of claim 3, Display device, characterized in that the light scattering surface is formed on at least one side of the liquid crystal panel.

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