JP2013195599A - Optical film and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical film that can prevent Newton's rings from occurring and can prevent a display unit and the optical film from adhering to each other without degrading visibility of a display screen.SOLUTION: An optical film includes plural types of minute protrusion shape 22 formed on the surface thereof regularly and having different heights. The optical film 14 is adhered to a back surface of a touch panel sensor 12 included in a touch-panel display device 10, thereby preventing Newton's rings from occurring and preventing a display unit 11 and the optical film 14 from adhering to each other without degrading visibility of a display screen.

Description

  The present invention relates to an optical film and a display device using the optical film.

  A liquid crystal display device with a touch panel is used as a display device in recent high-function or multifunctional mobile phones, tablet computers, and the like. The liquid crystal display device with a touch panel has a structure in which a touch panel sensor 82 is disposed on an LCD (Liquid Crystal Display) panel 81 as shown in FIG. Specifically, a cover glass 83 for protecting the display screen is disposed on the surface of the touch panel sensor 82, and the rear surface of the touch panel sensor 82 is used to prevent deterioration of the visibility of the display screen due to reflection of external light. The antireflection film 84 is attached with an adhesive (not shown). In addition, a gap 86 is formed by the spacer 85 between the LCD panel 81 and the touch panel sensor 82. When the touch panel sensor 82 is pressed by, for example, a human finger 87 through the cover glass 83, the touch panel type display device detects the position on the pressed touch panel sensor 82.

  Incidentally, in order to reduce the weight and thickness of the display device, it is necessary to reduce the gap 86 between the LCD panel 81 and the touch panel sensor 82. However, when the cover glass 83 is pressed, the cover glass 83, the touch panel sensor 82, and the antireflection film 84 are deflected by the pressure that presses the cover glass 83, so the gap between the LCD panel 81 and the touch panel sensor 82 When 86 is reduced, when the cover glass 83 is pushed, the gap 86 becomes extremely narrow as shown in FIG. 9, and as a result, interference fringes called Newton rings are generated, and the visibility of the display screen deteriorates. The problem occurs. Further, when a large deflection occurs such that the antireflection film 84 comes into contact with the LCD panel 81, for example, the human finger 87 is separated from the cover glass 83 after the contact, and the antireflection film 84 is released from the pressure. However, the antireflection film 84 remains adhered to the LCD panel 81, and there is a problem that the visibility deteriorates in a larger range.

  As an antireflection film for solving the above problems, as shown in FIG. 10, an antiglare film 91 having a fine convex shape on the surface is proposed in Patent Document 1. By using this anti-glare film 91 for a touch panel type display device, even when the cover glass is pressed and the touch panel sensor is bent, the LCD panel and the touch panel sensor are Since a certain air gap remains between, a Newton ring can be prevented from occurring. In addition, even when a large deflection occurs such that the antiglare film 91 comes into contact with the LCD panel, the contact area between the LCD panel and the antiglare film 91 is reduced by the fine convex shape of the antiglare film 91. Therefore, sticking between the LCD panel and the antiglare film 91 can be prevented.

  The fine convex shape of the antiglare film 91 is obtained by applying a resin material mixed with fine particles 94 made of amorphous silica or resin beads on the surface of the substrate 92, and forming an antiglare layer 93 made of the resin material. When forming, the fine particles 94 are deposited from the surface of the antiglare layer 93. When a fine convex shape is formed on the surface of the antiglare film 91 by such a method to prevent the occurrence of Newton rings, it is necessary to uniformly disperse the fine particles 94 in the antiglare layer 93.

  However, it is difficult to uniformly disperse the fine particles 94 in the antiglare layer 93 at an appropriate density, and the density of the fine particles 94 in the antiglare layer 93 varies. For this reason, the density of the fine particles 94 is partially increased, and there is a possibility that glare caused by light reflected on the convex surface may occur. On the other hand, there is a possibility that the density of the fine particles 94 is partially reduced, and Newton's ring and sticking between the antiglare film 91 and the LCD panel cannot be prevented.

International Publication No. 2009/001911

  The present invention solves the above-described conventional problems, and can prevent the occurrence of Newton rings and the adhesion between the LCD panel and the antireflection film without deteriorating the visibility of the display screen. An object is to provide an optical film and a display device using the optical film.

  The optical film of the present invention is characterized in that a plurality of types of fine protrusion shapes with different heights are formed regularly on the surface.

  In the optical film of the present invention, among the plurality of types of fine protrusion shapes having different heights, the fine protrusion shapes having the maximum height are arranged at predetermined pitch intervals, and the fine protrusions having the maximum height are arranged. A fine protrusion shape lower than the maximum height fine protrusion shape is arranged around the shape.

  The optical film of the present invention is characterized in that the fine protrusion shape has a flat surface at the tip.

  The optical film of the present invention is characterized in that a pitch interval of the fine protrusion shape is 100 μm or more and 500 μm or less, and a height of the fine protrusion shape is 1 μm or more and 10 μm or less.

  In addition, the optical film of the present invention is characterized in that it has a plurality of regions having different height distributions of the fine protrusion shape.

  Moreover, the display device of the present invention is a display device having a structure in which a display unit and a touch panel sensor are bonded to each other while holding a certain gap therebetween, and faces the display unit of the touch panel sensor. The above-described optical film is provided on the surface, and the fine protrusion shape is formed at a predetermined position on the surface of the optical film facing the display portion.

  Further, the display device of the present invention is characterized in that a plurality of regions having different height distributions of the fine protrusion shape are provided in the display screen.

  According to the present invention, since a plurality of types of fine protrusion shapes having different heights are regularly formed on the surface of the optical film, the display screen is visually recognized by attaching the optical film to the back surface of the touch panel sensor. It is possible to prevent the occurrence of Newton rings and the sticking between the display portion and the optical film without deteriorating the properties.

Sectional drawing which shows the outline of the example of 1 structure of the display apparatus in embodiment of this invention typically The partial expanded sectional view which shows the outline of the example of 1 structure of the optical film in embodiment of this invention typically The perspective view which shows an example of the fine protrusion shape in embodiment of this invention The layout which shows an example of the arrangement method of the fine projection shape in an embodiment of the invention Partial expanded sectional view which shows an example of the arrangement | positioning method of the fine protrusion shape in embodiment of this invention The top view which shows the other example of the arrangement | positioning method of the fine protrusion shape in embodiment of this invention Arrangement | positioning figure which shows the other example of the arrangement | positioning method of the fine protrusion shape in embodiment of this invention Sectional drawing which shows the structure of the conventional liquid crystal display device with a touch panel Sectional drawing which shows the state by which the touch panel is pressed of the conventional liquid crystal display device with a touch panel Sectional drawing which shows the structure of the conventional optical film

  Embodiments of the present invention will be described below with reference to the drawings, taking a liquid crystal display device with a touch panel as an example. However, the same components are denoted by the same reference numerals, and redundant description is omitted. It should be noted that the thickness, length, number, and the like of each illustrated component are different from actual ones for the convenience of drawing. In addition, the material, shape, dimensions, and the like of each component described below are merely examples, and are not particularly limited, and various changes can be made without departing from the effects of the present invention.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a liquid crystal display device with a touch panel in the present embodiment. As shown in FIG. 1, a liquid crystal display device 10 with a touch panel (hereinafter referred to as “display device 10”) has an LCD (Liquid Crystal Display) panel 11 that is a display unit of the liquid crystal display device and an input detection function. The touch panel sensor 12 has a structure in which a predetermined gap 16 is held between them to be bonded.

  The touch panel sensor 12 disposed on the LCD panel 11 includes a cover glass 13 made of a glass substrate, and an antireflection film 14 with a fine protrusion shape, which is an example of an optical film (hereinafter referred to as an “antireflection film 14”). Are attached so as to be optically connected to the touch panel sensor 12. Specifically, a cover glass 13 for protecting the display screen is affixed to the surface of the touch panel sensor 12, and the back surface of the touch panel sensor 12 is for preventing deterioration of the visibility of the display screen due to reflection of external light. An antireflection film 14 is affixed. The three components bonded together are fixed to the LCD panel 11 which is an example of a display unit via a spacer 15. Accordingly, a certain gap 16 is maintained by the spacer 15 between the LCD panel 11 and the touch panel sensor 12.

  When the operator presses the touch panel sensor 12 through the cover glass 13 with the finger 17 of the person to perform an input operation on the display device 10, the position on the pressed touch panel sensor 12. Is detected. At this time, the cover glass 13, the touch panel sensor 12, and the antireflection film 14 are bent, and the gap 16 is narrowed. That is, the distance between the antireflection film 14 and the LCD panel 11 decreases.

  Next, the antireflection film 14 will be described. FIG. 2 is a partially enlarged cross-sectional view showing a schematic configuration of the antireflection film 14 in the present embodiment. As shown in FIG. 2, the antireflection film 14 includes fine protrusions 22 regularly formed on the substrate 21. Such an antireflection film 14 can be realized, for example, by forming a resin such as an ultraviolet curable resin in a predetermined shape on a base material 21 made of a resin such as PET (polyethylene terephthalate) by an imprint method. .

  As shown in FIG. 3, the fine protrusion 22 may have a shape obtained by cutting the tip of the cone in the horizontal direction with the bottom surface of the cone. That is, the fine protrusion 22 may have a flat surface 31 at the tip. For example, when the antireflection film 14 having a fine protrusion shape on the surface thereof is manufactured by the imprint method, the fine protrusion shape is formed using a mold (mold). By making it part, it is possible to improve releasability.

  The elevation angle (the elevation angle of the cone) θ from the bottom surface of each side surface of the fine protrusions 22 regularly arranged on the surface of the antireflection film 14 (the surface of the base material 21) may be a constant value. However, with respect to their height h, a plurality of types exist in the plane of the antireflection film 14. In this embodiment, a plurality of fine protrusions 22 having a flat surface 31 having a cone elevation angle θ of 60 ° and a diameter φ of 0.5 μm on a PET base material 21 having a thickness of 100 μm are formed on the PET substrate 21. The case where the length h is varied in the range of 1 to 5 μm and regularly arranged will be described as an example.

  Here, the reason why the tip of the fine protrusion 22 is the flat surface 31 will be described. For example, when the cover glass 13 is pressed by a person's finger 17 and the touch panel sensor 12 is bent, if the fine protrusion formed in the bent area contacts the LCD panel 11, the fine protrusion Will receive pressure at the tip. For this reason, in the case of a cone-shaped fine protrusion with a sharp tip, the tip of the fine protrusion may be gradually rounded. Or the front-end | tip part of a microprotrusion may break. On the other hand, if the tip of the fine projection 22 is made flat in advance like the fine projection 22 shown in FIG. 3, the shape change and breakage of the tip of the fine projection 22 can be prevented. The film 14 can exhibit stable performance.

  Next, a method for arranging the fine protrusions 22 in the display screen will be described. FIG. 4 is an arrangement diagram showing an example of the arrangement method of the fine protrusions 22 in the present embodiment. FIG. 5 is a partially enlarged cross-sectional view showing an example of the arrangement method of the fine protrusions 22 in the present embodiment.

  In the arrangement example shown in FIG. 4, the fine protrusions 22 are arranged in a lattice pattern at a constant pitch interval p in the horizontal direction and the vertical direction in the display screen of the display device 10. Further, as the fine protrusions 22, three kinds of fine protrusion shapes of a large protrusion shape 22 a, a medium protrusion shape 22 b, and a small protrusion shape 22 c having different heights h are formed. In FIG. 4, the large protrusion shape 22a is indicated by a circle, the middle protrusion shape 22b is indicated by a triangle, and the small protrusion shape 22c is indicated by a cross. In addition, the height h of each protrusion shape 22a, 22b, 22c becomes large in order of the small protrusion shape 22c, the medium protrusion shape 22b, and the large protrusion shape 22a.

  In the arrangement example of the fine protrusions 22 shown in FIGS. 4 and 5, the large protrusion shape 22a is centered around the large protrusion shape 22a, and the medium protrusion shape 43 surrounds the periphery of the large protrusion shape 22a. A large protrusion shape 22 a, a medium protrusion shape 22 b, and a small protrusion shape 22 c are formed so as to surround 44.

  As shown in FIGS. 4 and 5, the large protrusion shape 22a, the middle protrusion shape 22b, and the small protrusion shape 22c are regularly arranged to prevent the occurrence of Newton rings without deteriorating the visibility of the display screen. In addition, adhesion between the LCD panel 11 and the antireflection film 14 can be prevented. Hereinafter, this reason will be described.

  In order to prevent the Newton ring from occurring when the cover glass 13 is pressed by, for example, a person's finger 17 and the touch panel sensor 12 is bent, the LCD panel 11 and the antireflection between the adjacent fine protrusions 22 are prevented. It is necessary to arrange the fine protrusions 22 so that the distance between the film 14 (gap 16) becomes 1 μm or more when the cover glass 13 is pressed. When all the fine protrusions 22 have the same shape, it is necessary to narrow the pitch interval p of the fine protrusions 22 to a certain value or less.

  As an example, a case where the gap 16 is 0.5 mm in a 10-inch touch panel liquid crystal display device will be described. In this case, for example, in order to prevent the Newton ring from being generated by arranging the fine protrusions 22 having a height h of 5 μm at a constant pitch interval p, the antireflection film 14 is most bent between the adjacent fine protrusions 22. In the central portion, the amount of deflection of the antireflection film 14 needs to be 4 μm or less, and for this purpose, the pitch interval p of the fine protrusions 22 needs to be set to 150 μm or less.

  By the way, since the fine protrusions 22 refract light from outside light, the height h of the fine protrusions 22 is increased, the volume is increased, and the total number of the fine protrusions 22 in the display screen is increased. Sex worsens. As described above, when the fine protrusions 22 having a height h of 5 μm are arranged at a pitch interval p of 150 μm, the presence of the fine protrusions 22 can be visually confirmed, causing a problem.

  On the other hand, the deflection amount of the touch panel sensor 12 when one point of the cover glass 13 disposed on the touch panel sensor 12 is pressed by, for example, a human finger 17 is linear with respect to the distance from the pressed position. Changes non-linearly. For this reason, in order to prevent the occurrence of Newton's ring, the height h of the fine protrusion 22 does not have to be uniform within the display screen, and the height h of the fine protrusion 22 is optimal in accordance with the non-linear deflection form. And visibility of the display screen can be prevented from deteriorating.

  For example, as three kinds of fine protrusions 22 having a height h, a large protrusion shape 22a having a height h of 5 μm, a medium protrusion shape 22b having a height h of 3 μm, and a small protrusion shape 22c having a height h of 1 μm, If it arrange | positions with the pitch space | interval p of 100 micrometers as shown in FIG.4 and FIG.5, generation | occurrence | production of a Newton ring can be prevented. In addition, since the pitch interval of the large protrusions 22a having a height of 5 μm that most deteriorates the visibility of the display screen is as large as 300 μm, it is possible to suppress the deterioration of the visibility of the display screen. In addition, the middle projection shape 22b and the small projection shape 22c whose pitch interval is narrower than the large projection shape 22a have little influence on the visibility of the display screen because the height h is small. Thus, by changing the height h of the fine protrusions 22 in three steps, it is possible to widen the pitch interval of the fine protrusions 22 having the maximum height h, thereby improving the visibility of the display screen. be able to.

  Subsequently, another example of the arrangement method of the fine protrusions 22 will be described. In the arrangement example of the fine protrusions 22 described above, the three kinds of fine protrusions 22 having a height h are regularly arranged at a constant pitch interval p on the entire surface of the display screen. However, the arrangement of the fine protrusions 22 is not limited to such an arrangement. For example, as shown in FIG. 6, a region 61 having a relatively high fine protrusion shape and a region 62 having a relatively low fine protrusion shape may be set in the display screen. Further, as the fine protrusions 22, three kinds of fine protrusion shapes of a large protrusion shape 22 a, a medium protrusion shape 22 b and a small protrusion shape 22 c having different heights h are arranged around the large protrusion shape 22 a with the large protrusion shape 22 a as a center. Even when the intermediate protrusion shape 22b surrounds the inner protrusion shape 22b and the small protrusion shape 22c surrounds the intermediate protrusion shape 22b, the intermediate protrusion shape 22b is not arranged at a constant pitch interval p as shown in FIG. As shown in FIG. 4, the pitch interval p1 between the large projection shape 22a and the middle projection shape 22b and the pitch interval p2 between the middle projection shape 22b and the small projection shape 22c are different from each other. The shape 22b and the small protrusion shape 22c may be arranged. In FIG. 7, the large protrusion shape 22a is indicated by a circle, the middle protrusion shape 22b is indicated by a triangle, and the small protrusion shape 22c is indicated by a cross. Further, the height h of each projection shape 22a, 22b, 22c increases in the order of the small projection shape 22c, the middle projection shape 22b, and the large projection shape 22a.

  The amount of deflection of the touch panel sensor 12 when one point of the cover glass 13 disposed on the touch panel sensor 12 is pressed by, for example, a human finger 17 is pressed by the outer peripheral portion of the display device 10 fixed by the spacer 15. And the case where the central part of the display device 10 is pressed. That is, the amount of deflection is small at the outer peripheral portion in the display screen. Therefore, as shown in FIG. 6, even if the fine protrusions 22 having a relatively low height h are formed in the outer peripheral region 62, the occurrence of Newton rings is prevented without deteriorating the visibility of the display screen. In addition, adhesion between the LCD panel 11 and the antireflection film 14 can be prevented.

  Further, as described above, the deflection amount of the touch panel sensor 12 when one point of the cover glass 13 arranged on the touch panel sensor 12 is pressed by, for example, a human finger 17 is a distance from the pressed point. On the other hand, it changes nonlinearly instead of linearly. That is, the amount of deflection between the adjacent fine protrusions 22 changes nonlinearly. Therefore, in addition to the height h of the fine protrusions 22, the pitch interval of the fine protrusions 22 can be optimized in accordance with the non-linear deflection form so that the visibility of the display screen does not deteriorate. For example, as shown in FIG. 7, even if the pitch interval p2 between the medium protrusion shape 22b and the small protrusion shape 22c is larger than the pitch interval p1 between the large protrusion shape 22a and the intermediate protrusion shape 22b, the display is performed. Without deteriorating the visibility of the screen, the generation of Newton rings can be prevented, and the adhesion between the LCD panel 11 and the antireflection film 14 can be prevented.

  Specifically, for example, in a liquid crystal display device with a touch panel having a size of 10 inches, the pitch interval p1 between the large protrusion shape 22a and the medium protrusion shape 22b is 150 μm, and the medium protrusion shape 22b and the small protrusion shape 22c are The pitch interval p2 between them is set to 300 μm, and the height h of the large protrusion shape 22a, the middle protrusion shape 22b, and the small protrusion shape 22c in the outer peripheral region 62 within a distance of 30 mm from the outer peripheral edge of the display screen is 3 μm, 1 .5 μm and 0.5 μm, and the height h of the large projection shape 22a, the middle projection shape 22b, and the small projection shape 22c in the central region 61 of the display screen inside the outer periphery is 5 μm, 3 μm, and 1 μm, respectively. When the gap 16 was made with a thickness of 0.5 mm, Newton rings could be prevented from occurring over the entire display screen. Further, the region 62 in which the height h of the fine protrusions 22 is reduced is set, and the total number of the fine protrusions 22 is reduced, which is compared with the arrangement method of the fine protrusions 22 described with reference to FIGS. Thus, the display device 10 with further improved visibility was obtained.

  As described above, according to this embodiment, in the display device 10 having a structure in which the LCD panel 11 and the touch panel 12 are bonded together with the spacer 15 between the LCD panel 11 and the touch panel 12, the display screen is displayed. By attaching an antireflection film 14 having a plurality of fine protrusions 22 having a predetermined shape, the height and arrangement of which are designed so as to minimize a reduction in visibility, to the back surface of the touch panel sensor 12, a touch panel is obtained. Even when the sensor 12 is deflected, the distance between the LCD panel 11 and the antireflection film 14 can be maintained at a certain value or more by the minute protrusions 22, and the occurrence of Newton rings can be prevented. Further, since the contact area between the LCD panel 11 and the antireflection film 14 can be reduced by the fine protrusions 22, it is possible to prevent the LCD panel 11 and the antireflection film 14 from sticking to each other.

  Furthermore, according to this embodiment, the highest fine protrusions 22 among a plurality of types of fine protrusions 22 having different heights are arranged on the surface of the antireflection film 14 at a predetermined pitch interval, By disposing the lower fine protrusions 22, the pitch interval of the highest fine protrusions 22 can be increased, and as a result, the visibility of the display screen can be improved. In this embodiment, the case where the height h of the fine protrusion 22 is changed in three stages has been described. However, the change in the height h of the fine protrusion 22 may be two or more stages.

  Further, according to this embodiment, by changing the height distribution of the fine protrusions 22 within the display screen, it becomes possible to minimize the height of the fine protrusion shape within the display screen. The display device 10 with improved performance can be realized. In this embodiment, the case where the display screen is divided into the two regions of the central region 61 and the outer peripheral region 62 has been described. However, three or more regions having different height distributions of the fine protrusions 22 are set in the display screen. You can also

  In order to prevent the Newton ring from occurring while preventing the visibility of the display screen from deteriorating, and to prevent the LCD panel 11 and the antireflection film 14 from coming into close contact with each other, for example, a touch panel sensor is used by a human finger 17. From the relationship between the pressure at which the pressure 12 is pressed and the amount of deflection of the touch panel sensor 12, the pitch interval of the fine protrusions 22 formed on the surface of the antireflection film 14 is preferably 100 μm or more and 500 μm or less. h is preferably 1 μm or more and 10 μm or less.

  Moreover, in the above description, although the antireflection sheet and the liquid crystal display device with a touch panel which are examples of the optical film and display device concerning this invention were demonstrated, the optical film and display device concerning this invention are limited to these. is not.

  The optical film and the display device according to the present invention can prevent Newton's ring from occurring without deteriorating the visibility of the display screen, and can prevent sticking between the display unit and the optical film. Alternatively, it is useful for a touch panel display device used for a multifunctional mobile phone, a tablet computer, or the like.

DESCRIPTION OF SYMBOLS 10 Liquid crystal display device with a touch panel 11 LCD panel 12 Touch panel sensor 13 Cover glass 14 Antireflection film with fine protrusion shape 15 Spacer 16 Air gap 17 Finger 21 Base material 22 Fine protrusion 22a Large protrusion shape 22b Medium protrusion shape 22c Small protrusion shape 31 Flat surface 61 Fine projection-shaped high region 62 Fine projection-shaped low region 81 LCD panel 82 Touch panel sensor 83 Cover glass 84 Antireflection film 85 Spacer 86 Gap 87 Finger 91 Antiglare film 92 Base material 93 Antiglare Layer 94 fine particles

Claims (7)

  An optical film comprising a plurality of types of fine protrusions having regularly different heights formed on a surface thereof.   Among the plurality of types of fine protrusion shapes having different heights, the fine protrusion shapes having the maximum height are arranged at predetermined pitch intervals, and the maximum height is arranged around the fine protrusion shape having the maximum height. 2. The optical film according to claim 1, wherein a fine protrusion shape lower than the fine protrusion shape is disposed.   The optical film according to claim 1, wherein the fine protrusion shape has a flat surface at a tip.   The optical film according to any one of claims 1 to 3, wherein a pitch interval of the fine protrusion shape is 100 µm or more and 500 µm or less, and a height of the fine protrusion shape is 1 µm or more and 10 µm or less.   The optical film according to claim 1, wherein the optical film has a plurality of regions having different height distributions of the fine protrusion shape. A display device having a structure in which a display unit and a touch panel sensor are bonded to each other while holding a certain gap between them,
The surface of the touch panel sensor facing the display unit includes the optical film according to any one of claims 1 to 4,
The fine projection shape is formed at a predetermined position on a surface of the optical film that faces the display unit.   The display device according to claim 6, wherein a plurality of regions having different height distributions of the fine protrusion shapes are provided in the display screen.

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