JP2009036880A - Antifouling film and display device having the same - Google Patents

Abstract

An object of the present invention is to improve display quality of a display device and to prevent contamination of an observation surface.
An antireflection layer comprising a single layer film or a laminated film of a plurality of thin films having different refractive indexes on a touch input panel disposed on an observation surface of a liquid crystal display element, and the antireflection layer. An antifouling film 17 is provided which is formed on 18 and is composed of an antifouling layer 19 formed by laminating silicon layers in the number of atoms of 20 or less.
[Selection] Figure 1

Description

  The present invention relates to an antifouling film and a display device including the same.

As a display device such as a liquid crystal display device, there is one in which a film made of an amorphous carbon film is provided on the observation surface to improve scratch resistance. (See Patent Document 1)
JP 2005-134542 A

  However, although the conventional amorphous carbon film has improved scratch resistance, it has been difficult to reduce the reflectance on the surface of the film.

  The present invention provides an anti-smudge film capable of obtaining a light anti-reflection effect and anti-smudge effect, and reduces surface reflection to improve display quality and to prevent the observation surface from becoming dirty. An object of the present invention is to provide a display device that can be used.

  An antifouling film for a display device according to claim 1 of the present invention is formed on a surface of a base material, and is a single layer film having a refractive index different from that of the base material, or a laminated film of a plurality of thin films having different refractive indexes from each other. And an antifouling layer which is formed on the antireflection layer and is formed by laminating silicon layers with a number of atoms of 20 or less.

  According to a second aspect of the present invention, in the antifouling film of the display device according to the first aspect, the antifouling layer is formed by laminating 3 to 10 silicon layers in number of atoms. To do.

The display device according to claim 3 of the present invention is
A display element for displaying an image;
An antireflection layer that is provided so as to cover the observation surface of the display element and has a single layer film having a refractive index different from that of the member that forms the observation surface of the display element, or a plurality of thin films having different refractive indexes from each other; An antifouling film formed on the antireflective layer, and comprising an antifouling layer formed by laminating silicon layers in a number of layers of 20 or less,
It is characterized by providing.

  According to a fourth aspect of the present invention, in the display device according to the third aspect, a touch input panel is disposed on the observation surface of the display element, and the antifouling film is formed on the touch input panel. It is characterized by being.

  According to a fifth aspect of the present invention, in the display device according to the third aspect of the present invention, the display element includes an observation side and a pair of substrates opposite to each other, which are arranged to face each other with a predetermined gap, and the pair of the display elements. An electric field for controlling the alignment state of liquid crystal molecules is applied to at least one of the liquid crystal layer sealed in the gap between the substrates and the inner surface of the pair of substrates facing the liquid crystal layer. A liquid crystal display element comprising a plurality of electrodes and a polarizing plate disposed on an outer surface of at least the observation side substrate of the pair of substrates, wherein the antifouling film is disposed on the observation side polarizing plate. It is formed.

  According to the antifouling film of the present invention, an antireflection effect of light and an antifouling effect can be obtained.

  Further, according to the display device of the present invention, the display quality can be improved and the observation surface can be prevented from being stained.

(First embodiment)
FIG. 1 is a cross-sectional view of a display device provided with an antifouling film according to a first embodiment of the present invention.

  The display device of this embodiment is a liquid crystal display device, and includes a liquid crystal display element 1 for displaying an image, a stain preventing film 17 provided so as to cover the observation surface (upper surface in FIG. 1) of the liquid crystal display element 1, The liquid crystal display device 1 includes a surface light source 20 that is disposed so as to face the surface opposite to the observation surface and that irradiates illumination light toward the liquid crystal display device 1.

  The liquid crystal display element 1 includes an observation side and a pair of transparent substrates 2 and 3 facing each other with a predetermined gap therebetween, and a liquid crystal layer sealed in the gap between the pair of substrates 2 and 3. 4 and a plurality of transparent electrodes 5 and 6 that are provided on the inner surfaces of the pair of substrates 2 and 3 facing the liquid crystal layer 4 and apply an electric field to the liquid crystal layer 4 for controlling the alignment state of liquid crystal molecules. And a pair of polarizing plates 9 and 10 disposed on the outer surfaces of the pair of substrates 2 and 3, respectively.

  The liquid crystal display element 1 is formed by arranging a plurality of pixel electrodes 6 in a matrix on the inner surface of the substrate 3 opposite to the observation side, and the plurality of pixel electrodes 6 on the inner surface of the substrate 2 on the observation side. The active matrix liquid crystal display element is formed with a single film-like counter electrode 5 corresponding to the array region, and although not shown in the figure, the inner surface of the substrate 3 on the opposite side is connected to the plurality of pixel electrodes 6. The TFTs (thin film transistors) arranged in correspondence with each other and connected to the pixel electrodes 6, a plurality of scanning lines for supplying gate signals to the TFTs in each row, and data signals to the TFTs in each column are supplied. A plurality of signal lines are provided. Although the plurality of pixel electrodes 6 are greatly exaggerated in the figure, the plurality of pixel electrodes 6 are arranged at a pitch of 50 to 100 μm, for example.

  In addition, on the inner surface of the substrate 2 on the observation side, there are three colors of red, green, and blue corresponding to a plurality of pixels each having a region where the plurality of pixel electrodes 6 and the counter electrode 5 face each other. Color filters 7R, 7G, and 7B are provided, and the counter electrode 5 is formed on the color filters 7R, 7G, and 7B.

  The pair of substrates 2 and 3 are joined together via a frame-shaped sealing material 8 surrounding a screen area made up of an array region of a plurality of pixels, and the sealing material 8 in the gap between the substrates 2 and 3 is used. The liquid crystal layer 4 is sealed in the enclosed area.

  Although not shown in the figure, an alignment film is provided on the inner surfaces of the pair of substrates 2 and 3 so as to cover the electrodes 5 and 6, respectively, and the liquid crystal molecules of the liquid crystal layer 4 include the pair of substrates. The substrates 2 and 3 are aligned in the alignment state defined by the alignment film.

  The liquid crystal display element 1 includes a TN or STN type in which liquid crystal molecules are twist-aligned, a vertical alignment type in which liquid crystal molecules are aligned substantially perpendicular to the surfaces of the substrates 2 and 3, and a substrate without twisting the liquid crystal molecules. Either a horizontal alignment type aligned substantially parallel to two or three planes, a bend alignment type in which liquid crystal molecules are bend aligned, or a ferroelectric or antiferroelectric liquid crystal display element, The polarizing plates 9 and 10 are arranged with their transmission axes oriented so as to obtain good contrast.

  In the liquid crystal display element 1 of this embodiment, an electric field is generated between the electrodes 5 and 6 provided on the inner surfaces of the pair of substrates 2 and 3 to change the alignment state of the liquid crystal molecules. For example, comb-like first and second electrodes for forming a plurality of pixels are provided on the inner surface of one of a pair of substrates, and a horizontal electric field (an electric field in a direction along the substrate surface) is provided between these electrodes. It may be of a lateral electric field control type that changes the alignment state of liquid crystal molecules.

  The liquid crystal display element 1 is a display element with a touch input panel in which a touch input panel 11 is arranged on an observation surface, and the antifouling film 17 is formed on the touch input panel 11.

  The touch input panel 11 is, for example, of a resistance type, and is placed opposite to each other with a predetermined gap, and is joined through a frame-shaped spacer 14 having a size surrounding the screen area of the liquid crystal display element 1. Alternatively, a pair of substrates 12 and 13 made of acrylic resin or the like, and a pair of transparent resistance films 15 made of ITO formed on the mutually facing inner surfaces of these substrates 12 and 13 in areas corresponding to substantially the entire area of the screen area, respectively. , 16.

  Although not shown in the drawing, a plurality of columnar spacers defining the interval between the resistance films 15 and 16 are provided in the row direction and on the film surface of one of the pair of resistance films 15 and 16. They are provided at a predetermined pitch in the column direction.

  The touch input panel 11 is arranged on the observation surface of the liquid crystal display element 1 with the outer surface of one substrate 12 facing the outer surface of the observation-side polarizing plate 9 of the liquid crystal display element 1. Hereinafter, the substrate 12 on the liquid crystal display element 1 side of the touch input panel 11 is referred to as a rear substrate, and the substrate 13 on the observation side is referred to as a front substrate.

  The touch input panel 11 has an outer surface of the antifouling film 17 formed thereon (on the front substrate 13) as a touch surface, and an arbitrary position on the touch surface is a touch pen (not shown). When the touch is applied, the anti-smudge film 17 and the portion corresponding to the touch position of the front substrate 13 are bent and deformed rearward, and the resistance film 16 on the inner surface of the front substrate 13 is locally applied to the inner surface of the rear substrate 12. It contacts the resistance film 15.

  Therefore, of the pair of resistance films 15 and 16, one direction of one resistance film 15, for example, between both ends in the X-axis direction, and the Y-axis direction orthogonal to the X-axis direction of the other resistance film 16. A voltage having a constant value is alternately applied between both ends of the first and the second resistance films 16 when the voltage in the X-axis direction is applied to the one resistance film 15, and the voltage value at one end in the Y-axis direction, By measuring the voltage value at one end in the X-axis direction of the one resistance film 15 when the voltage in the Y-axis direction is applied to the other resistance film 16, the touch is performed based on these voltage values. The coordinates of the position in the X-axis direction and the Y-axis direction can be detected.

  Meanwhile, the antifouling film 17 includes a transparent antireflection layer 18 formed on the front substrate 13 of the touch input panel 11, and a transparent antifouling layer 19 formed on the antireflection layer 18. It consists of.

Although the antireflection layer 18 is simplified in the drawing, a plurality of thin films having different refractive indexes, for example, a thin film made of niobium fluoride or titanium oxide and a thin film made of SiO ₂ (silicon oxide) are alternately arranged. In addition, each of the layers is made of a laminated film that is laminated in multiple layers with different film thicknesses.

  That is, this antireflection layer 18 reduces the reflection of wavelength light in the visible light band in the entire laminated film by appropriately setting the refractive index and the film thickness of the thin film forming each layer of the laminated film, It is an antireflection film that transmits light in the visible light band with high transmittance.

The thickness of the antireflection layer 18, the thickness of the laminated film, that is, the total film thickness of a film in which a plurality of the thin films made of niobium fluoride or titanium oxide and the thin film made of SiO ₂ are laminated is, for example, several tens to The range is 150 nm.

The SiO ₂ film is formed on the uppermost layer of the antireflection layer 18. On the uppermost SiO ₂ film of the antireflection layer 18, non-oxidized Si (silicon) is 20 atoms or less in number of atoms. An antifouling layer 19 made of a Si layer having a thickness of about 100 nm or less stacked in the number of layers is formed.

The uppermost SiO ₂ film of the antireflection layer 18 is formed by forming a Si film and oxidizing the Si film, and the antifouling layer 19 is formed by forming a Si film.

In that case, the SiO ₂ film is formed by sputtering the substrate to be deposited (second substrate of the touch input panel 11) 13 at 100 to 800 rpm in a 0.2 to 6 Pa Ar atmosphere with a sputtering apparatus. Rotating around the target at a rotation speed of about, and forming a film with a thickness of about 1 atomic layer (about 0.3 nm) under direct current plasma conditions with a power density of about 1 to 8 W / cm ² , the target is present In another region different from the region, it is formed by oxidizing the substantially one atomic layer of the deposited Si exposed to an Ar + O ₂ plasma atmosphere of about 0.2 to 6 Pa.

Then, each SiO ₂ film of the antireflection layer 18 is formed by repeatedly forming the substantially monoatomic Si film and oxidizing the Si film a number of times corresponding to the required film thickness. Further, the antifouling layer 19 formed on the uppermost SiO ₂ film of the antireflection layer 18 is formed by repeating the film formation of the substantially monoatomic layer of Si 20 times or less without being oxidized. .

The antifouling layer 19 made of the Si layer has a better antifouling property than the SiO ₂ film in order to keep the contact angle with water higher than the uppermost SiO ₂ film of the antireflection layer 18. It also has high wear resistance and chemical resistance.

  Moreover, the antifouling layer 19 is formed by laminating Si layers in the number of atoms of 20 or less, and the thickness thereof is extremely thin with respect to the wavelength of visible light. It does not affect the antireflection characteristics of the.

  The antifouling layer 19 is preferably a Si film in which the Si layer is laminated in 3 to 10 atoms. By setting the number of layers in this range, the antireflection property of the antireflection layer 18 is affected. It can be eliminated more effectively.

  Further, the surface light source 20 arranged to face the surface opposite to the observation surface of the liquid crystal display element 1 is made of a plate-like transparent member, and an incident end surface 21a for allowing light to enter is formed on one end surface thereof. A light exit surface 21b for light incident from the incident end surface 21a is formed on one of the two plate surfaces, and a light reflective surface that internally reflects light incident from the incident end surface 21a on the other plate surface toward the light exit surface 21b. The light guide plate 21 on which the light guide plate 21c is formed, and a plurality of light emitting elements 22 such as LEDs (light emitting diodes) disposed to face the incident end surface 21a of the light guide plate 21. The emission surface 21b is arranged to face the surface opposite to the observation surface of the liquid crystal display element 1.

  Since the display device is provided with the anti-smudge film 17 on the touch input panel 11 disposed on the observation surface of the liquid crystal display element 1, the display quality is improved and the observation surface, that is, the touch screen is improved. It is possible to prevent the touch surface of the input panel 11 from being soiled.

That is, the antifouling film 17 is formed on the antireflection layer 18 formed of a laminated film of a plurality of thin films having different refractive indexes (a thin film made of niobium fluoride or titanium oxide and a thin film made of SiO ₂ ). In which the antifouling layer 19 having a large contact angle with water and sufficiently thin compared with the wavelength of visible light is formed. The antireflection effect of light by 18 and the antifouling effect by the antifouling layer 19 can be obtained.

  Therefore, this display device can reduce the reflection by the observation surface, improve the visibility, and prevent the observation surface of the liquid crystal display element 1 from being soiled.

  In addition, the antifouling layer 19 which is the surface layer of the antifouling film 17 has high wear resistance and chemical resistance, and the antifouling layer 19 allows touch input to the touch input panel 11. Since the touch surface is formed, it is possible to prevent damage to the touch surface due to repeated touch input and peeling of the touch surface due to chemicals.

  In the above-described embodiment, the antireflection layer 18 of the antifouling film 17 is formed of a plurality of thin film stacks having different refractive indexes, but the antireflection layer 18 is formed on the touch input panel 11. A transparent material having a lower refractive index than that of the front substrate 13, for example, a single layer film of MgF (magnesium fluoride) may be used.

  Further, the antifouling layer 19 of the antifouling film 17 is not limited to the Si film, and a CSL (diamond-like carbon) layer formed by an ion plating method or the like is 20 or less (preferably 3). (10 layers) may be laminated, and in that case, the same effect as in the above embodiment can be obtained.

  Furthermore, in the said Example, the touch input panel 11 arrange | positioned at the observation surface of the liquid crystal display element 1 is a pair of board | substrates 12 and 13 opposingly arranged, and the resistance film formed in the inner surface of these board | substrates 12 and 13, respectively. 15 and 16, but the rear substrate 12 of the touch input panel 11 is omitted, and the resistance film 15 on the rear side of the resistance films 15 and 16 is used as an observation-side polarizing plate of the liquid crystal display element 1. You may form in the outer surface of 9.

  Further, the touch input panel 11 may be configured using the observation side substrate 2 and the observation side polarizing plate 9 of the liquid crystal display element 1, and in this case, the observation side polarizing plate 9 is configured as the observation side substrate 2. And the resistive films 15 and 16 may be formed on the opposing surfaces of the observation side substrate 2 and the observation side polarizing plate 9, respectively.

  Furthermore, the touch input panel disposed on the observation surface of the liquid crystal display element 1 is not limited to the resistive touch input panel of the above embodiment, but may be another type of touch input panel such as a low capacitance type or a magnetic field detection type.

(Second Embodiment)
FIG. 2 is a cross-sectional view of a display device provided with an antifouling film according to a second embodiment of the present invention. In this embodiment, components corresponding to those in the first embodiment are denoted by the same reference numerals, and description of substantially the same components is omitted.

  The display device according to this embodiment is the same as the display device according to the first embodiment except that the upper surface of the front substrate 13 of the resistive touch input panel 11 disposed on the observation surface of the liquid crystal display element 1 is placed on the touch input panel 11. Another antireflection layer 18a made of substantially the same film as the antireflection layer 18 of the antifouling film 17 is formed, and the other configuration is the same as that of the first embodiment.

  In the display device of this embodiment, an antifouling film 17 including an antireflection layer 18 and an antifouling layer 19 formed thereon is provided on the touch input panel 11 disposed on the observation surface of the liquid crystal display element 1. Further, since the antireflection layer 18a is also formed on the inner surface of the front substrate 13 of the touch input panel 11, the light irradiated from the surface light source 20 and transmitted through the liquid crystal display element 1 is observed with high transmittance. The brightness and contrast of the display can be further increased.

(Third embodiment)
FIG. 3 is a cross-sectional view of a display device provided with an antifouling film according to a third embodiment of the present invention. In this embodiment, components corresponding to those in the first embodiment are denoted by the same reference numerals, and description of substantially the same components is omitted.

  In the display device of this embodiment, the resistive touch input panel 11 arranged on the observation surface of the liquid crystal display element 1 in the display device of the first embodiment is omitted, and the observation side polarizing plate 9 of the liquid crystal display device 1 is omitted. The antifouling layer 17 comprising the antireflection layer 18 and the antifouling layer 19 formed thereon is provided thereon, and the other configurations are the same as those of the first embodiment.

(Other embodiments)
In addition, the display apparatus of each Example mentioned above is provided with the transmissive | pervious liquid crystal display element 1, and arrange | positions the surface light source 20 on the opposite side to the observation side of this liquid crystal display element 1, but as a liquid crystal display element, A reflective liquid crystal display element in which a reflection film is provided on the inner surface or outer surface of the substrate opposite to the observation side, and one polarizing plate is disposed on the outer surface of the observation side substrate, and the surface light source 20 is omitted. May be.

  Furthermore, the display element for displaying an image is not limited to a liquid crystal display element, and may be a plasma display element, an organic EL (electroluminescence) display element, or the like.

  The anti-smudge film 17 can be used not only for display devices but also for other optical devices.

1 is a cross-sectional view of a display device provided with an antifouling film according to a first embodiment of the present invention. Sectional drawing of the display apparatus provided with the antifouling film | membrane which shows 2nd Example of this invention. Sectional drawing of the display apparatus provided with the antifouling film | membrane which shows the 3rd Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display element, 2, 3 ... Board | substrate, 4 ... Liquid crystal layer, 5, 6 ... Electrode, 7R, 7G, 7B ... Color filter, 9, 10 ... Polarizing plate, 11 ... Touch input panel, 12, 13 ... Substrate , 15, 16 ... resistance film, 17 ... antifouling film, 18, 18a ... antireflection layer, 19 ... antifouling layer, 20 ... surface light source.

Claims (5)

  An antireflection layer formed on the surface of the base material and made of a single layer film having a refractive index different from that of the base material or a laminated film of a plurality of thin films having a refractive index different from each other, and formed on the antireflection layer, silicon An antifouling film comprising an antifouling layer formed by laminating these layers in an atom number of 20 or less.   2. The antifouling layer according to claim 1, wherein the antifouling layer is formed by laminating 3 to 10 silicon layers. A display element for displaying an image;
An antireflection layer that is provided so as to cover the observation surface of the display element and has a single layer film having a refractive index different from that of the member that forms the observation surface of the display element, or a plurality of thin films having different refractive indexes from each other; An antifouling film formed on the antireflective layer, and comprising an antifouling layer formed by laminating silicon layers in a number of layers of 20 or less,
A display device comprising:   The display device according to claim 3, wherein a touch input panel is disposed on an observation surface of the display element, and a stain prevention film is formed on the touch input panel.   The display element includes an observation side and a pair of substrates opposite to each other which are arranged to face each other with a predetermined gap, a liquid crystal layer sealed in a gap between the pair of substrates, and the liquid crystal layer of the pair of substrates A plurality of electrodes that are provided on at least one of the inner surfaces facing each other and apply an electric field for controlling the alignment state of liquid crystal molecules to the liquid crystal layer; and at least an outer surface of the observation-side substrate of the pair of substrates. The display device according to claim 3, wherein the display device is a liquid crystal display element including a polarizing plate arranged, and the antifouling film is formed on the polarizing plate on the observation side.

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