JP2020148820A - Display device and method for manufacturing display device - Google Patents

Abstract

To provide a display device which improves manufacturing efficiency and can suppress lowering of reliability.SOLUTION: A display device includes a display panel, an optical film bonded to the display panel, a transparent cover member having a first main surface and a second main surface opposite to the first main surface, a coloring part provided on the first main surface of the cover member, and a scattering film which is provided between the optical film and the cover member, and is bonded to the optical film, the coloring part, the transparent resin layer in contact with the first main surface and the second main surface of the cover member.SELECTED DRAWING: Figure 2

Description

An embodiment of the present invention relates to a display device and a method for manufacturing the display device.

In recent display devices, ultraviolet curable adhesives are often used to bond the cover glass to the surface of the display panel. A black frame that defines the viewing area is formed on the cover glass by printing or the like. When ultraviolet rays are applied while such a frame overlaps with the adhesive, a part of the adhesive may not be sufficiently cured. The uncured portion of the adhesive may flow out or contain air bubbles. Therefore, the reliability may be lowered.
As a manufacturing device for such a display device, a technique is disclosed in which a light guide block arranged on a cover glass via a resin is provided and ultraviolet rays are irradiated from the side surface of the light guide block.

JP-A-2017-146451

An object of the present embodiment is to provide a display device and a method for manufacturing the display device, which can improve the manufacturing efficiency and suppress the decrease in reliability.

According to this embodiment
A display panel, an optical film adhered to the display panel, a transparent cover member having a first main surface and a second main surface opposite to the first main surface, and the first main surface of the cover member. A transparent resin layer provided between the optical film and the cover member and in contact with the optical film, the colored portion, and the first main surface, and the cover member. A display device comprising a scattering film adhered to a second main surface is provided.
According to this embodiment
A display panel, a transparent cover member having a first main surface and a second main surface opposite to the first main surface, a scattering film having a Lambert scattering surface adhered to the second main surface, and the first. A method for manufacturing a display device, which is located between one main surface and the display panel and includes an ultraviolet curable adhesive for adhering the first main surface and the display panel, and is irradiated with ultraviolet rays. Then, in the irradiation step of curing the adhesive, a method for manufacturing a display device is provided in which the ultraviolet rays are irradiated toward the Lambert scattering surface of the scattering film.

FIG. 1 is a plan view of the display device DSP of the present embodiment. FIG. 2 is a cross-sectional view showing a configuration example of a display device DSP along the line AB shown in FIG. FIG. 3 is a diagram for explaining the scattering of incident light by the scattering film 30. FIG. 4 is a diagram for explaining a comparative example. FIG. 5 is a cross-sectional view showing another configuration example of the display device DSP along the line AB shown in FIG. FIG. 6 is a cross-sectional view showing another configuration example of the display device DSP along the line AB shown in FIG. FIG. 7 is a cross-sectional view showing another configuration example of the display device DSP along the line AB shown in FIG.

Hereinafter, the present embodiment will be described with reference to the drawings. It should be noted that the disclosure is merely an example, and those skilled in the art can easily conceive of appropriate changes while maintaining the gist of the invention are naturally included in the scope of the present invention. Further, in order to clarify the description, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is merely an example, and the present invention It does not limit the interpretation. Further, in the present specification and each figure, components exhibiting the same or similar functions as those described above with respect to the above-mentioned figures may be designated by the same reference numerals, and duplicate detailed description may be omitted as appropriate. ..

FIG. 1 is a plan view of the display device DSP of the present embodiment. The display device DSP includes a display panel PNL and a cover member 10.

The display panel PNL includes a liquid crystal panel having a liquid crystal layer between a pair of substrates, an organic electroluminescence element, a panel having a self-luminous element such as a micro LED (light-emitting diode) and a mini LED, and an electrophoresis element. It may be any of a panel, a panel to which MEMS (micro electro mechanical systems) is applied, a panel to which electrochromism is applied, and the like. An electronic component such as a touch panel may be provided instead of the display panel PNL. In the example shown in FIG. 1, the display panel PNL includes a first substrate SUB1 and a second substrate SUB2, and an IC chip 2, a flexible wiring board 4, and the like are mounted on the display panel PNL. The display panel PNL includes a display area DA for displaying an image.

The cover member 10 is provided so as to overlap the display panel PNL in a plan view. In the example shown in FIG. 1, the cover member 10 is formed larger than the display panel PNL. The outer end portion E1 of the cover member 10 is located outside the outer end portion E2 of the display panel PNL over the entire circumference thereof. At least a part of the outer end portion E1 may be superimposed on the outer end portion E2, or the outer end portion E1 may be located inside the outer end portion E2 over the entire circumference. The cover member 10 is a transparent substrate and is made of glass or resin.

The cover member 10 includes a frame-shaped colored portion 11 that defines the viewing area VA. The colored portion 11 is shown by diagonal lines in the figure. The viewing area VA is superimposed on the display area DA. The colored portion 11 is colored black, for example, but may be colored in another color. The colored portion 11 is superimposed on the IC chip 2 and the flexible wiring board 4 in a plan view.

FIG. 2 is a cross-sectional view showing a configuration example of a display device DSP along the line AB shown in FIG. Although the display panel PNL includes pixels PX, it is shown in a simplified manner here. The display area DA corresponds to the area where the pixels PX are arranged.

The optical film OF is adhered to the display panel PNL via the transparent adhesive layer A1. In one example, the optical film OF is adhered to the second substrate SUB2 shown in FIG. The optical film OF is, for example, a polarizing plate, but may include a retardation plate, a protective layer, a coating layer, an antireflection layer, and the like in addition to the polarizing plate.

The cover member 10 has a first main surface 10A facing the display panel PNL and a second main surface 10B on the opposite side of the first main surface 10A. The coloring portion 11 is provided on the first main surface 10A. Such a colored portion 11 is formed on the first main surface 10A by a method such as printing and is cured. The inner end portion 11E of the coloring portion 11 defines the viewing area VA.

The resin layer 20 is provided between the optical film OF and the cover member 10. Further, the resin layer 20 is in contact with the optical film OF on the lower surface side thereof, and is in contact with the first main surface 10A and the colored portion 11 on the upper surface side thereof, respectively. The resin layer 20 adheres the optical film OF bonded to the display panel PNL and the cover member 10. The resin layer 20 is transparent and overlaps the display area DA and the viewing area VA. Such a resin layer 20 is formed of, for example, an ultraviolet curable adhesive that is initially liquid but is cured by being irradiated with ultraviolet rays. Further, the resin layer 20 may be formed of a double-sided pressure-sensitive adhesive sheet.

In one example, the thickness T of the resin layer 20 superimposed on the colored portion 11 is 0.050 to 0.25 mm. The width W of the resin layer 20 (or the width between the outer end portion 20E of the resin layer 20 and the inner end portion 11E of the coloring portion 11) W of the region superposed on the coloring portion 11 is 0.05 to 3.0 mm. is there.

The scattering film 30 is adhered to the second main surface 10B of the cover member 10 via the transparent adhesive layer A2. The scattering film 30 has a first surface 30A facing the second main surface 10B and a second surface 30B on the opposite side of the first surface 30A. The first surface 30A is adhered to the second surface 30B by the adhesive layer A2 without passing through the air layer.

The first refractive index n1 of the scattering film 30 is the same as or larger than the second refractive index n2 of the cover member 10. In one example, the second refractive index n2 is about 1.5 and the first refractive index n1 is about 1.58. The refractive indexes of the resin layer 20 and the optical film OF are equivalent to the second refractive index n2.

In one example, the scattering film 30 has a haze of 80% or more, and more preferably 90% or more. The haze of the present embodiment is defined as the ratio of the diffusion transmittance to the total light transmittance (diffusion transmittance / total light transmittance). In the example shown in FIG. 2, the surface roughness of the second surface 30B is larger than the surface roughness of the first surface 30A. The first surface 30A is a substantially smooth surface, and the second surface 30B is a surface having minute irregularities. As will be described later, the second surface 30B, which is a surface having minute irregularities of the scattering film 30, may be a Lambert scattering surface for Lambert scattering of incident light, and has a prism shape other than the prism shape shown in the example of FIG. It may be a surface that has been subjected to a textured surface treatment. A scattering film having a Lambert scattering surface is not limited to a minute uneven structure.

The adhesive force of the scattering film 30 to the cover member 10 by the adhesive layer A2 is smaller than the adhesive force of the optical film OF to the display panel PNL by the adhesive layer A1. The adhesive force (or peeling force) between the scattering film 30 and the cover member 10 is, for example, 0.01 to 0.5 N / 25 mm. Therefore, the scattering film 30 can be easily peeled off together with the adhesive layer A2, and the adhesive layer A2 hardly remains on the second main surface 10B of the cover member 10 after the peeling. Further, the adhesive layer A2 is a detachable member having the above-mentioned slight adhesiveness and which can be attached to the cover member again by the above-mentioned slight adhesive after being peeled from the cover member 10.
The refractive index of the adhesive layer A2 is the same as the second refractive index n2 of the cover member, or larger than the second refractive index n2, and is equivalent to the first refractive index n1 of the scattering film 30.

As one application of the scattering film 30, the scattering film 30 is applied as a protective film that protects the cover member 10 in the manufacturing process. The scattering film 30 in this case is packed together with the display device DSP or the electronic device equipped with the display device DSP. The scattering film 30 applied in such an application is peeled off by the end user. As shown in FIG. 2, the scattering film 30 is superposed on the display area DA and the viewing area VA, and is also provided directly above the coloring portion 11. When the scattering film 30 is applied as a protective film, it is desirable that the scattering film 30 covers almost the entire surface of the cover member 10. Further, as will be described later, if the effect of curing the resin layer 20 under the colored portion 11 can be obtained, it is necessary that the structure overlaps with the colored portion 11 of the cover member 10 in order to cause Lambert scattering. However, for example, it may have a structure for causing Lambert scattering only on substantially the entire surface of the display area DA or the viewing area VA.

FIG. 3 is a diagram for explaining the scattering of incident light by the scattering film 30. Here, a case where the ultraviolet curable adhesive 21 is cured to form the resin layer 20 will be described. The state shown in FIG. 3 is a state in which the adhesive 21 is uncured. The ultraviolet rays for curing the adhesive 21 are emitted through the scattering film 30. In the figure, the optical path of light having an ultraviolet wavelength is indicated by an arrow.

The scattering film 30 scatters (Lambert scattering) the incident light from the second surface 30B and emits it from the first surface 30A. That is, the scattered light in the scattering film 30 is isotropically scattered in the cover member 10 and passes through the cover member 10. The scattered light reaches the region of the adhesive 21 that overlaps the viewing area VA (that is, the region where the colored portion 11 is not provided). In addition, a part of the scattered light also reaches the adhesive 21 directly under the colored portion 11.

Here, the range in which the scattered light reaches immediately below the colored portion 11 will be examined. When the first refractive index n1 of the scattering film 30 is equal to the second refractive index n2 of the cover member 10 and the refractive index of the adhesive 21 is equal to the second refractive index n2, the scattered light scattered by the scattering film 30 is covered. The member 10 and the adhesive 21 go straight. In this case, the relationship between the thickness T of the adhesive 21 superimposed on the colored portion 11 and the maximum distance D of the scattered light that the light beam having the refraction angle θr can reach is expressed by the following relational expression.
D = T * tanθr
Therefore, by setting the width W between the outer end portion 21E of the adhesive 21 and the inner end portion 11E of the coloring portion 11 to a range smaller than the maximum distance D of the above relational expression, the scattered light of ultraviolet rays is colored. It reaches almost the entire area of the adhesive 21 in the range superimposed on the portion 11. As a result, not only the adhesive 21 superimposed on the viewing area VA but also the adhesive 21 located directly below the colored portion 11 absorbs ultraviolet rays and is cured.

Therefore, immediately below the colored portion 11, the outflow of the adhesive 21 and the generation of air bubbles due to the uncured part of the adhesive 21 are suppressed. As described above, according to the present embodiment, it is possible to suppress a decrease in reliability.

Further, since the scattering film 30 applied in the ultraviolet irradiation step can also be applied as a protective film, the cover member 10 can be protected in the manufacturing process after the irradiation step. Further, since the scattering film 30 can be packed together with the display device DSP or the electronic device as a protective film, the step of peeling the scattering film 30 in the manufacturing process after the irradiation step is not required. Therefore, the manufacturing efficiency can be improved.

Further, when the adhesive 21 is cured, it is not necessary to irradiate ultraviolet rays from the side (that is, the outer end portion 21E of the adhesive 21), only the ultraviolet irradiation from the front surface (that is, the normal direction of the cover member 10). Therefore, the adhesive 21 can be sufficiently cured immediately under the colored portion 11.

FIG. 4 is a diagram for explaining a comparative example. Here, a comparative example in which the scattering film 30 is omitted from the display device DSP shown in FIG. 3 will be examined. The second main surface 10B of the cover member 10 serves as an interface with the air layer. When the refractive index of the cover member 10 and the resin layer 20 (strictly speaking, the adhesive 21 before curing) is 1.5, when the incident angle θi of ultraviolet rays is set to 89 °, the refractive angle θr is less than 50 °. Become. Therefore, theoretically, the range in which ultraviolet rays can reach the adhesive 21 directly under the colored portion 11 is limited to a region having a width W1 substantially equal to the thickness T of the adhesive 21. As an example, when the thickness T is 0.15 mm, the width W1 is 0.17 mm.

On the other hand, as described above, according to the display device DSP of the present embodiment to which the scattering film 30 is applied, ultraviolet rays emitted from the front of the display device DSP are scattered by the scattering film 30 to substantially disperse the cover member 10 and the adhesive 21. Go straight. The refraction angle θr of the scattered light shown in FIG. 3 is larger than the refraction angle θr of the comparative example shown in FIG. Therefore, in the adhesive 21 directly under the coloring portion 11, the reachable range of ultraviolet rays can be expanded, and the adhesive force of the adhesive 21 can be improved.

Next, another configuration example will be described.

FIG. 5 is a cross-sectional view showing another configuration example of the display device DSP along the line AB shown in FIG. The configuration example shown in FIG. 5 is different from the configuration example shown in FIG. 2 in that the scattering film 30 contains a fine particle-like filler (scattered particles) 31. Such a scattering film 30 also has a haze of 80% or more, and scatters incident light having an ultraviolet wavelength from the second surface 30B and emits it from the first surface 30A.
Therefore, even in such a configuration example, the same effect as described above can be obtained.

FIG. 6 is a cross-sectional view showing another configuration example of the display device DSP along the line AB shown in FIG. The configuration example shown in FIG. 6 is different from the configuration example shown in FIG. 2 in that the scattering layer 40 is provided between the optical film OF and the coloring portion 11.
The scattering layer 40 contains a fine particle-like filler (scattering particles) 41. The base material of the scattering layer 40 may be an organic material, an inorganic material, a conductive material, or an insulating material. The filler 41 may be formed of a conductive material or an insulating material. When the scattering layer 40 has conductivity, the charging of the optical film OF can be suppressed.

In the example shown in FIG. 6, the scattering layer 40 is provided on the upper surface OFA of the optical film OF. Further, the scattering layer 40 is separated from the colored portion 11, and the resin layer 20 is interposed between the scattering layer 40 and the colored portion 11.
The length L between the inner end portion 11E of the colored portion 11 and the scattering layer 40 is shorter than the maximum distance D shown in FIG. Therefore, when ultraviolet rays are irradiated through the scattering film 30 when forming the resin layer 20, a part of the scattered light that reaches directly under the colored portion 11 is scattered in the scattering layer 40. The scattered light in the scattering layer 40 reaches the adhesive 21 in contact with the scattering layer 40 and contributes to the curing of the adhesive 21. That is, according to this configuration example, the ultraviolet rays can be guided to a region further separated from the viewing area VA as compared with the case where the scattering layer 40 is not provided. Therefore, even when the frame width of the colored portion 11 is relatively large, the adhesive 21 superimposed on the colored portion 11 can be sufficiently cured.

Further, the length L is the same as or larger than the thickness T of the resin layer 20 superimposed on the colored portion 11. Therefore, even when the display device DSP is observed at a viewing angle inclined by 45 ° with respect to the normal of the inner end portion 11E in the viewing area VA, the scattering layer 40 is not visually recognized.

FIG. 7 is a cross-sectional view showing another configuration example of the display device DSP along the line AB shown in FIG. The configuration example shown in FIG. 7 is different from the configuration example shown in FIG. 6 in that the scattering layer 40 is provided on the lower surface 11A of the coloring portion 11. In the example shown in FIG. 7, the scattering layer 40 is separated from the optical film OF, and the resin layer 20 is interposed between the optical film OF and the scattering layer 40.
Even in such a configuration example, the same effect as that of the configuration example shown in FIG. 6 can be obtained.

The scattering layer 40 may be provided so as to be in contact with both the optical film OF and the coloring portion 11. Further, in the configuration examples shown in FIGS. 6 and 7, the scattering film 30 may include the filler 31 as in the configuration example shown in FIG.

As described above, according to the present embodiment, it is possible to provide a display device and a method for manufacturing the display device, which can improve the manufacturing efficiency and suppress the decrease in reliability.

Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other embodiments, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are also included in the scope of the invention described in the claims and the equivalent scope thereof.

DSP ... Display device PNL ... Display panel 10 ... Cover member 20 ... Resin layer 30 ... Scattering film 40 ... Scattering layer

Claims (13)

Display panel and
The optical film adhered to the display panel and
A transparent cover member having a first main surface and a second main surface opposite to the first main surface,
A colored portion provided on the first main surface of the cover member and
A transparent resin layer provided between the optical film and the cover member and in contact with the optical film, the colored portion, and the first main surface.
A scattering film adhered to the second main surface of the cover member and
A display device. The display device according to claim 1, wherein the first refractive index of the scattering film is the same as or larger than the second refractive index of the cover member. The display device according to claim 1 or 2, wherein the scattering film has a haze of 80% or more. The scattering film has a first surface facing the second main surface and a second surface opposite to the first surface.
The display device according to claim 3, wherein the surface roughness of the second surface is larger than the surface roughness of the first surface. The display device according to claim 3, wherein the scattering film contains a fine particle filler. The display device according to any one of claims 1 to 5, wherein the adhesive force of the scattering film is smaller than the adhesive force of the optical film. The display device according to any one of claims 1 to 6, wherein the resin layer is formed of an ultraviolet curable adhesive. The display device according to any one of claims 1 to 6, wherein the resin layer is formed of a double-sided pressure-sensitive adhesive sheet. The display device according to any one of claims 1 to 8, further comprising a scattering layer provided between the optical film and the colored portion. The colored portion has an inner end portion that defines a viewing area.
The display device according to claim 9, wherein the distance between the inner end portion and the scattering layer is the same as or larger than the thickness of the resin layer. Display panel and
A transparent cover member having a first main surface and a second main surface opposite to the first main surface,
A scattering film having a Lambert scattering surface adhered to the second main surface, and
A method for manufacturing a display device, which is located between the first main surface and the display panel and includes an ultraviolet curable adhesive that adheres the first main surface and the display panel.
In the irradiation step of irradiating ultraviolet rays and curing the adhesive,
A method for manufacturing a display device, wherein the ultraviolet rays are emitted toward the Lambert scattering surface of the scattering film. The scattering film is adhered to the second main surface of the cover member by an adhesive in the pre-process of the irradiation step.
The method for manufacturing a display device according to claim 11, wherein the scattering film covers the entire surface of the second main surface. The method for manufacturing a display device according to claim 11 or 12, wherein the scattering film functions as a protective cover for the cover member in a subsequent step of the irradiation step.

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