Patent Description:
For example, a display device that displays image light, as described in Patent Literature <NUM>, has been known. Such a display device is usually observed in black when no image is displayed. Meanwhile, design properties are very important in, for example, surface members for automobiles, furniture, and housing building materials, and the like. At present, display devices applied in various fields are expected not only to have a function of simply displaying an image, but also to be in harmony with the surrounding environment in terms of design properties.

In order to impart the design properties to the display device, it has been proposed to provide a decorative sheet so as to face a display surface of the display device. The decorative sheet can impart the design properties in harmony with the surrounding environment of the display device. Further, in order to allow the image light of the display device to transmit through the decorative sheet, such a decorative sheet has a light transmitting portion such as a hole in a region facing the display surface of the display device, as described in Patent Literature <NUM>.

<CIT>
, <CIT>, <CIT> and <CIT> disclose display devices with decorative sheets comprising plurality of transmitting portions.

Patent Literature <NUM> discloses that the spacing between the holes in a colored front panel is smaller than the pixel size of a dot matrix display in order to make an image on a display device clear. However, Patent Literature <NUM> mainly presupposes a single color front panel, and does not assume a decorative sheet having a complicated picture pattern such as wood grain texture or marble texture.

The present invention has been made in view of the above points, and an object of the invention is to provide a decorative sheet, a display system, and a display system with a panel that are excellent in visibility of a picture pattern of the decorative sheet.

In order to solve the above problems, the decorative sheet according to the present invention, as defined in appended claim <NUM>, includes a picture pattern portion and a plurality of transmitting portions that are portions in which the picture pattern portion is not formed, wherein an aperture ratio is <NUM>% or more and <NUM>% or less, and each of the transmitting portions is formed such that a distance between the transmitting portions adjacent to each other is <NUM> or more and <NUM> or less.

In addition, the picture pattern portion may include a pattern that is not monochromatic and contain an inorganic pigment or an organic pigment.

Further, each of the transmitting portions may have a circular shape when observed from a normal direction of the decorative sheet. The transmitting portions may be arranged in a grid pattern when observed from the normal direction of the decorative sheet. Each of the transmitting portions may be formed such that the distance between the transmitting portions adjacent to each other is <NUM> or more.

The decorative sheet according to the present invention may further include a base material portion that supports the picture pattern portion and each of the transmitting portions, and each of the transmitting portions may be formed of a transparent material having a refractive index of ±<NUM> of a refractive index of the base material portion.

The display system according to the present invention includes a display device having a display surface and the decorative sheet that is described above and provided to face the display surface. Further, in one embodiment of the display system according to the present invention the display device is a dot matrix display, and a pitch of the transmitting portions is larger than a pitch of pixels on the display surface. The display surface may include a non-light emitting portion that is configured as a black matrix having a width of <NUM> or more and <NUM> or less.

In a further embodiment, the display system according to the present invention further includes a panel member that is arranged between the display surface and the decorative sheet.

According to the present invention, it is possible to achieve the decorative sheet, the display system, and the display system with a panel that are excellent in visibility of a picture pattern of the decorative sheet.

Hereinafter, one of the embodiments of the present invention (hereinafter, referred to as "present embodiment") will be described with reference to the drawings. In the drawings attached to the present specification, the scale, aspect ratio, and the like are appropriately changed from the actual ones and exaggerated for the convenience of illustration and understanding.

Note that, in the present specification, the terms "layer", "sheet", and "film" are not distinguished from each other based only on the difference in designation. For example, the term "sheet" is a concept that also includes members that may be called layers or films.

In addition, as used in the present specification, the terms such as "parallel", "orthogonal", and "identical" and the values of length and angle that specify the shape, geometric conditions, and degree thereof are interpreted so as to include the range in which similar functions can be expected without being bound by the strict meaning.

A decorative sheet <NUM>, a display system <NUM> with a decorative sheet, and a display system <NUM> with a panel according to the present embodiment will be described.

<FIG> is an exploded perspective view schematically illustrating the display system <NUM> with a panel according to the present embodiment. <FIG> is an enlarged front view of the decorative sheet <NUM> according to the present embodiment. <FIG> is a cross-sectional view of the display system <NUM> with a panel according to the present embodiment.

The decorative sheet <NUM> includes a picture pattern portion <NUM> on which a picture pattern is formed, and a transmitting portion <NUM> that transmits image light from a display surface <NUM> of a display device <NUM>.

The display system <NUM> with a decorative sheet includes the display device <NUM> having the display surface <NUM> and the decorative sheet <NUM> provided so as to face the display surface <NUM>.

The display system <NUM> with a panel includes the display device <NUM> having the display surface <NUM> and a panel <NUM> provided so as to face the display surface <NUM>, and the panel <NUM> includes a panel member <NUM> having an opening 30a and the decorative sheet <NUM>.

The display system <NUM> with a panel is thus configured such that image light emitted from the display surface <NUM> of the display device <NUM> passes through the opening 30a of the panel member <NUM> and the transmitting portion <NUM> of the decorative sheet <NUM> to be observed by an observer from the normal direction of the display surface <NUM>.

In the example of <FIG>, the decorative sheet <NUM>, the display system <NUM> with a decorative sheet, and the display system <NUM> with a panel are illustrated in a flat plate shape, but these components may have a curved shape.

The display device <NUM> is a device that emits image light, and includes the display surface <NUM> capable of emitting image light. The display device <NUM> according to the present embodiment is a dot matrix liquid crystal display. The decorative sheet <NUM>, the display system <NUM> with a decorative sheet, and the display system <NUM> with a panel according to the present invention are configured to be suitably used particularly in a display device with a dot matrix display. Examples of the dot matrix display include, in addition to a liquid crystal display, an organic EL display, an inorganic EL display, a plasma display, an LED display, a millimeter LED display, a micro LED display, and a quantum dot display. Further, it is preferable that the display device <NUM> can emit image light having a luminance of <NUM> cd/m<NUM> or more from the viewpoint of the visibility of image light observed through the transmitting portion <NUM> of the decorative sheet <NUM>.

The panel member <NUM> is arranged between the display device <NUM> and the decorative sheet <NUM>, and includes the opening 30a. The panel member <NUM> is, for example, a plate-like member having a thickness of <NUM>. The panel member <NUM> is arranged so that the display surface <NUM> of the display device <NUM> is located in the opening 30a when observed from the normal direction to the display surface <NUM>.

The panel member <NUM> includes a base material layer <NUM> and a design layer <NUM> provided on the base material layer <NUM>. The base material layer <NUM> is a member capable of properly supporting the design layer <NUM>. The design layer <NUM> is a member for imparting design property to the panel member <NUM>, and is typically a dark color such as black. Such a design layer <NUM> is formed of, for example, a resin containing a black pigment. Examples of the black pigment include carbon black and titanium black. The design layer <NUM> may impart any design property such as wood grain texture or marble texture depending on the environment in which the panel member <NUM> is provided. Further, if the design layer <NUM> is not required, the design layer <NUM> may be eliminated.

The panel member <NUM> of the present embodiment has a hollow square shape having the rectangular opening 30a. However, the embodiment of the present invention is not limited thereto, and the panel member <NUM> may have a shape obtained by removing a part of a rectangle, such as an L-shape or a U-shape. Further, the panel member <NUM> is not limited to a rectangular shape, and may have any shape such as a circular shape. Furthermore, the opening 30a may also have any shape.

Further, the panel member <NUM> of the present invention may be formed such that the opening 30a is not formed and a portion facing the display surface <NUM> of the display device <NUM> is transparent. Furthermore, the panel member <NUM> may be composed of the transparent base material layer <NUM> and the design layer <NUM>, and may have the opening 30a only in the design layer <NUM>. Moreover, the panel member <NUM> may be entirely transparently formed without having the design layer <NUM>. Further, the panel member <NUM> may be formed as a semitransparent smoke plate as a whole.

The decorative sheet <NUM> includes a base material portion <NUM>, the picture pattern portion <NUM> and a shielding portion <NUM> provided on the base material portion <NUM>, and the transmitting portion <NUM> that is a portion in which the picture pattern portion <NUM> and the shielding portion <NUM> are not formed.

The base material portion <NUM> properly supports the picture pattern portion <NUM> and the shielding portion <NUM> provided on the base material portion <NUM>. The base material portion <NUM> is a transparent film-like member. Any material that can transmit visible light and properly support the picture pattern portion <NUM> and the shielding portion <NUM> may be used for the base material portion <NUM>, and examples of the material include polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polystyrene, and cyclic polyolefin. Further, the base material portion <NUM> preferably has a thickness of <NUM> or more and <NUM> or less in view of visible light transmission properties and proper supportability of the picture pattern portion <NUM> and the shielding portion <NUM>.

The shielding portion <NUM> is arranged between the picture pattern portion <NUM> and the base material portion <NUM>, and covers the picture pattern portion <NUM> from the side of the base material portion <NUM>. The shielding portion <NUM> has a function of absorbing light so that the image light from the display surface <NUM> of the display device <NUM> does not enter the picture pattern portion <NUM>. The shielding portion <NUM> may contain, for example, light absorbing particles in a binder resin. Examples of the light absorbing particles include black pigments such as carbon black and titanium black. As a specific example, the thickness of the shielding portion <NUM> is <NUM> or more and <NUM> or less.

Any picture pattern such as wood grain texture, marble texture, geometric patterns, carbon texture, stripes, polka dots, and single color may be formed in the picture pattern portion <NUM>. However, the decorative sheet <NUM> according to the present invention is configured such that the picture pattern portion suitably includes a picture pattern such as wood grain texture and marble texture, or a picture pattern formed by using pigments such as mica, iron oxide, aluminum powder, and carbon black.

The resolution of the picture pattern portion <NUM> is preferably <NUM> dpi (dot pitch of about <NUM>) or higher from the viewpoint of the clarity of the design of the picture pattern portion <NUM> to be observed, and is more preferably <NUM> dpi (dot pitch of about <NUM>) or higher from the viewpoint of the clarity of the design having substantially the same resolution as a photo magazine or a catalog. Further, from similar viewpoints, the picture pattern portion <NUM> is preferably formed by printing <NUM> or more of printing lines, and is more preferably formed by printing <NUM> or more of printing lines.

The picture pattern portion <NUM> is covered by the shielding portion <NUM> from the side of the display device <NUM>. The shielding portion <NUM> prevents image light from entering the picture pattern portion <NUM>. Consequently, it is possible to prevent the image light from being transmitted through the picture pattern portion <NUM>, and the design represented by the picture pattern portion <NUM> and the image light from being observed in a mixed manner. That is, it is possible to effectively prevent the color reproducibility of an image from being degraded due to the absorption of visible light in a specific wavelength range in the picture pattern portion <NUM>.

The transmitting portion <NUM> is a portion in which the picture pattern portion <NUM> is not formed when observed from the front of the decorative sheet <NUM>, and can transmit image light from the display surface <NUM> of the display device <NUM>.

The transmitting portion <NUM> of the present embodiment is formed of a transparent resin having a refractive index of ± <NUM> of the refractive index of the base material portion <NUM>. The transmitting portion <NUM> may be a hole or a void. However, as a result of research, the inventors of the present invention have found that, if the transmitting portion <NUM> is formed of a transparent resin having a refractive index of ± <NUM> of the refractive index of the base material portion <NUM>, the transmitting portion <NUM> becomes less noticeable when the decorative sheet is observed closely. Since an acrylic resin having a refractive index of <NUM> to <NUM> is usually used as the base material portion <NUM> of the decorative sheet <NUM>, a polymethyl methacrylate resin, a fluorine resin, a silicone resin, polypropylene, a urethane resin, polyethylene, nylon, polyvinyl chloride, epoxy, polycarbonate, polystyrene and the like having a refractive index of <NUM> to <NUM> are preferable as the material of the transmitting portion <NUM>.

Further, the transmitting portion <NUM> formed of such a transparent resin may cover the picture pattern portion <NUM> and the shielding portion <NUM>, as illustrated in <FIG>. Such a transmitting portion <NUM> functions as a transparent protective film that protects the picture pattern portion <NUM> and the shielding portion <NUM>.

Note that in the present specification, "transparent" in "transparent base material" means the transparency to the extent that the transparent base material can be seen through from its one side toward the other side, and has a visible light transmittance of, for example, <NUM>% or more, more preferably <NUM>% or more. The visible light transmittance is specified as the average value of the transmittance at each wavelength measured within a measurement wavelength range of <NUM> to <NUM> using a spectrophotometer ("UV-3100PC" manufactured by SHIMADZU CORPORATION, JIS K <NUM> compliant product).

<FIG> is an enlarged front view illustrating an arrangement of the transmitting portions <NUM> of the decorative sheet <NUM> according to the present embodiment.

In a state where an image is displayed on the display surface <NUM> of the display device <NUM>, image light is transmitted through the opening 30a of the panel member <NUM> and the transmitting portion <NUM> of the decorative sheet <NUM>, and is observed by an outside observer. The ratio of the transmitting portion <NUM> to the area of the decorative sheet <NUM> facing the display surface <NUM> of the display device <NUM> (hereinafter referred to as "aperture ratio") is preferably <NUM>% or more so that the observer can observe the image light that meets practical use as a display device, and more preferably <NUM>% or more so that the observer can observe the image light with sufficient brightness. Further, this aperture ratio is preferably <NUM>% or more and more preferably <NUM>% or more when a high-brightness display is used as the image light, and is preferably <NUM>% or more when a normal display is used as the image light.

In a case where no image is displayed on the display surface <NUM> of the display device <NUM>, the picture pattern on the picture pattern portion of the decorative sheet <NUM> is observed. The aperture ratio of the decorative sheet <NUM> is preferably <NUM>% or less so that the observer can clearly observe the design of the decorative sheet <NUM> that meets practical use, and is more preferably <NUM>% or less so that the observer can observe the design of the decorative sheet <NUM> more clearly. In addition, this aperture ratio is preferably <NUM>% or less in order to allow the limited pattern design to be clearly observed, preferably <NUM>% or less in order to allow high-brightness designs including silver and pearl to be clearly observed, and preferably <NUM>% or less in order to allow normal designs such as wood grain to be clearly observed and the presence of the display device <NUM> to be sufficiently concealed.

The aperture ratio of the decorative sheet <NUM> is the ratio of the area occupied by the transmitting portion <NUM> to the decorative sheet <NUM>, and can be calculated using the formula (aperture ratio) = (total area of transmitting portion <NUM>) / ((total area of picture pattern portion <NUM>) + (total area of transmitting portion <NUM>)).

The transmitting portion <NUM> of the decorative sheet <NUM> according to the present embodiment is formed by arranging the circular transmitting portions <NUM> in a square grid pattern when observed from the normal direction of the decorative sheet <NUM>. The transmitting portions <NUM> do not need to be arranged in a square grid pattern and in a grid pattern. However, when the transmitting portions <NUM> are formed in a grid pattern, the image light from the display device <NUM> is uniformly transmitted, so that the image on the display device <NUM> is less likely to be uneven. Further, when the transmitting portions <NUM> are arranged in a square grid pattern, the image on the display device <NUM> is less likely to be uneven. Consequently, as for the transmitting portion <NUM> of the decorative sheet <NUM>, the circular transmitting portions <NUM> are preferably arranged in a grid pattern, and are more preferably arranged in a square grid pattern when observed from the normal direction of the decorative sheet <NUM>. Furthermore, the transmitting portion <NUM> does not need to be circular. However, as will be described later, in order to suppress the diffusion of image light, the transmitting portion <NUM> of the decorative sheet <NUM> preferably has a circular shape when observed from the normal direction.

The transmitting portion <NUM> of the decorative sheet <NUM> according to the present embodiment is formed so that the distance between adjacent transmitting portions <NUM> is <NUM> or more. Here, the distance between the adjacent transmitting portions <NUM> means the distance between the edges of the adjacent transmitting portions <NUM>. Further, the description that the distance between the adjacent transmitting portions <NUM> is <NUM> or more means that a shorter distance of distances D1 and D2 between the adjacent transmitting portions <NUM> is <NUM> or more when the transmitting portions <NUM> are formed in a grid pattern, and means that the average distance from each transmitting portion <NUM> to the closest transmitting portion <NUM> is <NUM>µ or more when the transmitting portions <NUM> are formed in a mode other than the grid pattern. In other words, in this embodiment, the shortest distance from the outer edge of one transmitting portion <NUM> freely selected to the outer edge of the other transmitting portion <NUM> is <NUM> or more.

As a result of research, the inventors of the present invention have found that when the picture pattern portion <NUM> of the decorative sheet <NUM> is observed at a short distance in a state where no image is displayed on the display device <NUM>, if the distance between adjacent transmitting portions <NUM> is increased and the area of a region 53A where the picture pattern portion <NUM> surrounded by the transmitting portion <NUM> is continuous is also increased, the details of the picture pattern, which has the pattern of the decorative sheet <NUM>, can be seen sharply, and conversely, if the distance between the adjacent transmitting portions <NUM> is reduced and the area of the region 53A where the picture pattern portion <NUM> surrounded by the transmitting portion <NUM> is continuous is also reduced, the details of the picture pattern of the decorative sheet <NUM> becomes blurred.

Furthermore, the inventors of the present invention have found that when the distance between adjacent transmitting portions <NUM> is longer than a distance corresponding to the size that can be identified by people, the details of the picture pattern having a pattern can be seen properly sharply. The size that can be identified by people with a visual acuity of <NUM> at a distance of <NUM>, which is a typical usage condition when the picture pattern having a pattern is consciously observed in a case where no image is displayed on the display device <NUM>, is about <NUM>. Consequently, when the distance between the adjacent transmitting portions <NUM> is <NUM> or more, the details of the picture pattern having the pattern of the decorative sheet <NUM> look sharp enough to be suitable for practical use. As a result, it is preferable to form the transmitting portion <NUM> so that the distance between adjacent transmitting portions is <NUM> or more. The size that can be identified by people with a visual acuity of <NUM> at a distance of <NUM>, which covers most of the usage condition assumed when the picture pattern having a pattern is consciously observed in a case where no image is displayed on the display device <NUM>, is about <NUM>. Consequently, when the distance between the adjacent transmitting portions <NUM> is <NUM> or more, the details of the picture pattern having the pattern of the decorative sheet <NUM> look sharp enough to be suitable for practical use. As a result, it is more preferable to form the transmitting portion <NUM> so that the distance between the adjacent transmitting portions <NUM> is <NUM> or more.

The size that can be identified by people can be calculated using the formula (size that can be identified by people [m]) = 2n / <NUM> / <NUM> / (visual acuity) × (distance to target [m]).

Meanwhile, when an image is displayed on the display device <NUM>, if the distance between the adjacent transmitting portions <NUM> is longer than or equal to the distance corresponding to the size that can be identified by people, the image on the display device <NUM> is observed to be separated for each transmitting portion <NUM> of the decorative sheet <NUM>.

The image on the display device <NUM> is usually observed from a distance of <NUM> or more, and in many cases about <NUM>, assuming a display device installed in an automobile. The size that can be identified by people with a visual acuity of <NUM> at a distance of <NUM> is about <NUM>. Consequently, assuming that the distance between the adjacent transmitting portions <NUM> is <NUM> or less, the image on the display device <NUM> is observed without being separated for each transmitting portion <NUM> of the decorative sheet <NUM>. In addition, the size that can be identified by people with a visual acuity of <NUM> at a distance of <NUM> is about <NUM>. Further, since the size that car be identified by people with a visual acuity of <NUM> at a distance of <NUM> is about <NUM>, the transmitting portion <NUM> is formed so that the distance between the adjacent transmitting portions <NUM> is <NUM> or less.

The size of the transmitting portion <NUM> is set so that the aperture ratio of the decorative sheet <NUM> is an appropriate value. As specific values of the distance between the adjacent transmitting portions <NUM> and the diameter of the transmitting portion <NUM>, for example, it is assumed that the distance between the adjacent transmitting portions <NUM> is <NUM> and the diameter of the transmitting portion <NUM> is also <NUM>, and the aperture ratio of the decorative sheet <NUM> in this case is about <NUM>%.

<FIG> is an enlarged front view of the decorative sheet <NUM> in a case where the picture pattern portion <NUM> of the decorative sheet <NUM> contains a pearl pigment 53a or the like. The upper figure of <FIG> is an enlarged front view before the transmitting portion <NUM> is formed. The lower left figure of <FIG> is an enlarged front view after the transmitting portion <NUM> is formed so that the distance between adjacent transmitting portions <NUM> is <NUM> or more. The lower right figure of <FIG> is an enlarged front view after the transmitting portion <NUM> is formed so that the distance between the adjacent transmitting portions <NUM> is less than <NUM>.

The pearl pigment 53a is obtained by coating the surface of thin plate-like mica particles with titanium dioxide, and usually has a size of about <NUM> to several tens of µm. For this reason, if the transmitting portion <NUM> is formed so that the distance between the adjacent transmitting portions <NUM> is less than <NUM>, as illustrated in the lower right figure of <FIG>, most of the pearl pigments 53a contained in the picture pattern portion <NUM> come off when the transmitting portion <NUM> is formed. On the other hand, if the transmitting portion <NUM> is formed so that the distance between the adjacent transmitting portions <NUM> is <NUM> or more, as illustrated in the lower left figure of <FIG>, most of the pearl pigments 53a in the region surrounded by the transmitting portion <NUM> remain. This is not limited to pearl pigments, but also applied to other inorganic pigments or organic pigments such as flaky aluminum pigments. Examples of the inorganic pigment or the organic pigment include oxides, hydroxides, sulfides, chromates, silicates, sulfates, carbonates, pearl pigments, aluminum powders, carbons and the like.

Consequently, in the decorative sheet including the pearl pigment 53a or the like in the picture pattern portion <NUM>, it is preferable to form the transmitting portion <NUM> so that the distance between the adjacent transmitting portions <NUM> is <NUM> or more. Further, if the distance between the adjacent transmitting portions <NUM> is <NUM> or more, the pearl pigment 53a is less likely to come off when the transmitting portion <NUM> is formed. Therefore, it is more preferable to form the transmitting portion <NUM> so that the distance between the adjacent transmitting portions <NUM> is <NUM> or more.

<FIG> is an enlarged front view illustrating a state where the decorative sheet <NUM> is arranged so as to face the display surface <NUM> of the dot matrix liquid crystal display <NUM>. The upper figure of <FIG> is an enlarged front view illustrating the display surface <NUM> of the liquid crystal display <NUM>. The lower left figure of <FIG> is an enlarged front view in a case where the decorative sheet <NUM> is arranged in which the transmitting portion <NUM> is formed so that the pitch of the transmitting portion <NUM> of the decorative sheet <NUM> is larger than the pitch of a pixel 41a of the display surface <NUM>. The lower right figure of <FIG> is an enlarged front view in a case where the transmitting portion <NUM> is formed so that the pitch of the transmitting portion <NUM> of the decorative sheet <NUM> is less than the pitch of the pixel 41a of the display surface <NUM>.

Here, the pitch of the transmitting portion <NUM> refers to a distance P1, P2 between the centers of the adjacent transmitting portions <NUM>, and the pitch of the pixel 41a refers to a distance p1, p2 between the centers of the adjacent pixels 41a. When the liquid crystal display <NUM> is a color display, one dot including RGB sub-pixels corresponds to the pixel 41a. The pitch of the pixel 41a is, for example, <NUM> in a <NUM>-inch liquid crystal display with <NUM> × <NUM> pixels, <NUM> in an <NUM>-inch liquid crystal display with <NUM> × <NUM> pixels, <NUM> in a <NUM>-inch liquid crystal display with <NUM> × <NUM> pixels, and <NUM> in a <NUM>-inch liquid crystal display with <NUM> × <NUM> pixels.

As illustrated in the upper figure of <FIG>, the display surface <NUM> of the liquid crystal display <NUM> includes a plurality of the pixels 41a arranged in a grid pattern and a non-light emitting portion 41b between the pixels 41a. The non-light emitting portion 41b between the pixels 41a is usually configured as a black matrix, and its width is about <NUM> to <NUM>. As illustrated in the lower left figure and the lower right figure of <FIG>, most of the plurality of transmitting portions <NUM> of the decorative sheet <NUM> overlap the non-light emitting portion 41b of the display surface <NUM> of the liquid crystal display <NUM>.

Consequently, the possibility that the transmitting portion <NUM> of the decorative sheet overlaps a specific region of the non-light emitting portion 41b of the display surface <NUM> of the liquid crystal display <NUM> in a case where the pitch of the transmitting portion <NUM> is less than the pitch of the pixel 41a is higher than that in a case where the pitch of the transmitting portion <NUM> is larger than the pitch of the pixel 41a.

Further, assuming that the aperture ratio of the decorative sheet <NUM> is constant, when the pitch of the transmitting portion <NUM> increases, the area occupied by one transmitting portion <NUM> on the decorative sheet <NUM> also increases, and when the pitch of the transmitting portion <NUM> decreases, the area occupied by one transmitting portion <NUM> on the decorative sheet <NUM> also decreases. That is, assuming that the aperture ratio of the decorative sheet <NUM> is constant, when the pitch of the transmitting portion <NUM> increases, the transmitting portions <NUM> having a large area are arranged at a large pitch, and when the pitch of the transmitting portion <NUM> decreases, the transmitting portions <NUM> having a small area are arranged at a small pitch.

As illustrated in the lower left figure of <FIG>, in a case where the pitch of the transmitting portion <NUM> is larger than the pitch of the pixel 41a, even if the transmitting portion <NUM> overlaps the non-light emitting portion 41b of the display surface <NUM> of the liquid crystal display <NUM>, the ratio of a portion overlapping the non-light emitting portion 41b to one transmitting portion <NUM> is sufficiently small. Therefore, the amount of image light transmitting through the transmitting portion <NUM> only decreases slightly. On the other hand, as illustrated in the lower right figure of <FIG>, in a case where the pitch of the transmitting portion <NUM> is less than the pitch of the pixel 41a, if the transmitting portion <NUM> overlaps the non-light emitting portion 41b of the display surface <NUM> of the liquid crystal display <NUM>, the ratio of the portion overlapping the non-light emitting portion 41b to one transmitting portion <NUM> significantly increases. Therefore, the amount of image light transmitting through the transmitting portion <NUM> significantly decreases.

Consequently, in the decorative sheet <NUM> in which the transmitting portion <NUM> is formed so that the pitch of the transmitting portion <NUM> is less than the pitch of the pixel 41a, the transmitting portion <NUM> having very little image light is periodically generated, which adversely affects an image to be observed. In order to prevent the occurrence of such an adverse effect, it is necessary to properly arrange and accurately align the transmitting portions <NUM> so that the transmitting portion <NUM> does not overlap the non-light emitting portion 41b of the display surface <NUM> of the liquid crystal display <NUM>.

From these viewpoints, it is preferable to form the transmitting portion <NUM> so that the pitch of the transmitting portion <NUM> is larger than the pitch of the pixel 41a.

Further, in the decorative sheet <NUM> according to the present embodiment, the pitch of the transmitting portion <NUM> and the pitch of the pixel 41a preferably have a relationship of Y < X(A × X + B) from the viewpoint of suppressing the occurrence of moire as described below, where the pitch of the transmitting portion <NUM> is denoted by X and the pitch of the pixel 41a is denoted by Y. Here, A and B are constants obtained by theoretical calculations using the observation results of the decorative sheet <NUM> actually produced, as described below.

As described above, the transmitting portion <NUM> of the decorative sheet <NUM> according to the present embodiment is formed by arranging the circular transmitting portions <NUM> in a square grid pattern when observed from the normal direction of the decorative sheet <NUM>. Further, the pixels 41a of the dot matrix display are also usually arranged in a square grid pattern. As described above, since it is preferable that the pitch of the transmitting portion <NUM> is larger than the pitch of the pixel 41a, the pitch of the transmitting portion <NUM> and the pitch of the pixel 41a are usually different. That is, the transmitting portion <NUM> and the pixel 41a have a different periodic pattern. Consequently, when the decorative sheet <NUM> having such a transmitting portion <NUM> and the display having such a pixel 41a are overlapped with each other, there is a problem that moire is generated due to the difference in the period of the periodic patterns of the transmitting portion <NUM> and the pixel 41a.

In general, a pitch Pm of a moire periodic pattern generated when a periodic pattern having the pitch Pa and a periodic pattern having pitch Pb are overlapped is calculated from the relational expression of Pm = Pa·Pb / |Pa - Pb|. As a result of research, the inventors of the present invention have found that the occurrence of moire that is visually recognized by an observer can be suppressed by setting the pitch Pm of the moire periodic pattern generated from the periodic pattern of the transmitting portion <NUM> and the periodic pattern of the pixel 41a to a certain value or less. As will be described below, it has been found that this constant value is preferably <NUM> based on the correlation between the observation results of the decorative sheet <NUM> actually produced and the results of theoretical calculations.

The observation results of the decorative sheet <NUM> actually produced are indicated in Table <NUM>. "O" indicates that no moire is observed. "×" indicates that moire is observed. "△" indicates that moire is slightly observed.

The theoretical calculation is basically performed by substituting the values of the pitch X of the transmitting portion <NUM> and the pitch Y of the pixel 41a into the above equation of Pm = Pa·Pb / |Pa - Pb| for the purpose of calculating the moire pitch Pm (= X·Y / |X-Y|). When the moire pitch Pm is a certain value that is set appropriately or less, it is determined as "○", and when the moire pitch Pm is larger than the certain value, it is determined as "×", so that a table similar to Table <NUM> is created. A plurality of such tables are created with different constant values, and these tables are compared with Table <NUM> that shows the observation results of the decorative sheet <NUM> actually produced. As a result, it has been found that when the constant value is set to <NUM>, the table created by the theoretical calculation matches Table <NUM> that shows the observation results of the decorative sheet <NUM> actually produced. Table <NUM> is a table created by the theoretical calculation when the constant value is set to <NUM>.

The actual theoretical calculation is performed by taking the period at a bias angle of <NUM> to <NUM> degrees into consideration in view of the decorative sheet <NUM> extending two-dimensionally. Specifically, the moire pitch Pm at each of ten bias angles of <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, <NUM> degrees, and <NUM> degrees is calculated, and when the number of the moire pitches Pm that are equal to or larger than the constant value is less than five, it is determined as "○", and when the number of such moire pitches Pm is larger than or equal to five, it is determined as "×".

<FIG> is a graph illustrating a relationship between the pitch X of the transmitting portion and the pitch Y of a pixel under the boundary condition where moire is generated. In this graph, the horizontal axis indicates the pitch X of the transmitting portion <NUM>, the vertical axis indicates the ratio Y/X of the pitch Y of the pixels 41a to the pitch X of the transmitting portion <NUM>, and a value is plotted, the value being obtained when it is determined as "×" for the first time in a case where the pitch of a pixel is increased at each of the pitches of the transmitting portion in Table <NUM>. It is understood from <FIG> that the pitch X of the transmitting portion <NUM> and the ratio Y/X of the pitch Y of the pixel 41a to the pitch X of the transmitting portion <NUM> under the boundary condition where moire is generated have a substantially linear relationship. Such a linear relationship has been found as a result of research by the inventors of the present invention.

Consequently, from the viewpoint of suppressing the occurrence of moire, it is preferable to achieve the relationship of Y/X < (A x X + B), that is, Y < X·(A × X + B), where the pitch of the transmitting portion <NUM> is denoted by X and the pitch of the pixel 41a is denoted by Y. Further, it can be said from <FIG> that preferably, A = -<NUM> and B = <NUM>, where the unit of X and Y is µm. That is, from the viewpoint of suppressing the occurrence of moire, it is preferable to achieve the relationship of Y [µm] < X [µm]·(-<NUM> × X [µm] + <NUM>), where the pitch of the transmitting portion <NUM> is denoted by X and the pitch of the pixel 41a is denoted by Y.

<FIG> is an enlarged front view for explaining light scattering at an edge of the transmitting portion <NUM> of the decorative sheet <NUM>. As illustrated in <FIG>, the edge of the transmitting portion <NUM> of the decorative sheet <NUM> has fine irregularities, and the image light transmitting through the transmitting portion <NUM> is scattered by these irregularities.

The shorter the edge length of the transmitting portion <NUM> per unit area when observed from the normal direction of the decorative sheet <NUM>, the more the scattering of the image light is suppressed. When the aperture ratio of the decorative sheet <NUM> is constant, the longer the distance between adjacent transmitting portions <NUM>, the shorter the edge length of the transmitting portion <NUM> per unit area, and the image light is less scattered. Consequently, even if the transmitting portion <NUM> is formed so that the distance between the adjacent transmitting portions is <NUM> or more, the scattering of the image light is suppressed, so that degradation in an image on the display device <NUM> is also suppressed.

A circle has the shortest peripheral length among the figures having the same area. For this reason, the transmitting portion <NUM> of the decorative sheet <NUM> preferably has a circular shape when observed from the normal direction.

Samples A, B, and C in which circular transmitting portions <NUM> were formed in a square grid pattern on the decorative sheet <NUM> having the picture pattern portion <NUM> printed in black were produced under the following conditions, and the diffuse reflectance of these samples was measured using a spectrophotometer CM-600d manufactured by KONICA MINOLTA INC. (measurement conditions: light source C, field of view of two degrees).

The ratio of edge lengths per unit area is A:B:C = <NUM>:<NUM>:<NUM>. The measured diffuse reflectance was A: <NUM>%, B: <NUM>%, and C: <NUM>%. As described above, the shorter the edge length of the transmitting portion <NUM> per unit area, the lower the light diffusivity.

The decorative sheet <NUM> according to the present embodiment has the above characteristics, but from the viewpoint of improving the visibility of the design of the picture pattern portion <NUM> on the decorative sheet <NUM>, values of the reflectance and haze preferably fall within a certain range to be described below.

The reflectance of the decorative sheet <NUM> is preferably <NUM>% or more and <NUM>% or less, and more preferably <NUM>% or more and <NUM>% or less. The lower limit value of the reflectance range, <NUM>%, is a value obtained when the pattern of the picture pattern portion <NUM> is solid black. When the reflectance is <NUM>% or more, the visibility of the design of the picture pattern portion <NUM> is sufficiently improved. However, when the reflectance exceeds <NUM>%, the image light from the display device <NUM> and the reflected light from the picture pattern portion <NUM> is mixed, and the visibility of the image light is degraded. This reflectance value is a luminance reflectance value measured with a D65 light source and a field of view of <NUM>°. An example of the measurement method is as follows.

The haze of a decorative sheet is preferably <NUM>% or more and <NUM>% or less. The lower limit value of this haze range, <NUM>%, is the production limit. If the haze exceeds <NUM>%, the scattering of the image light transmitting through the transmitting portion <NUM> becomes too large, and the visibility of the image light is degraded. This haze value is measured according to JIS K <NUM>. An example of the measurement method is as follows.

In order to keep the reflectance and haze values of a decorative sheet within the above ranges, it is preferable that the picture pattern portion <NUM> contains a glitter pigment such as a silver pigment or a pearl pigment. In particular, when the picture pattern portion <NUM> is formed by multicolor printing, the glitter pigment such as a silver pigment or a pearl pigment is preferably used for at least one color.

The preferred embodiment of the decorative sheet <NUM> according to the present embodiment has been described above, but from the viewpoint of overall performance, the decorative sheet <NUM> according to the present embodiment is preferably a decorative sheet in which the aperture ratio is <NUM>% or more and <NUM>% or less, the resolution of the picture pattern portion <NUM> is <NUM> dpi or more, the reflectance is <NUM>% or less, the haze is <NUM>% or less, and the picture pattern portion <NUM> contains a glitter pigment.

Finally, the method of forming the transmitting portion <NUM> of the decorative sheet <NUM> will be described.

For example, the transmitting portion <NUM> is formed as follows. First, the picture pattern portion <NUM> and the shielding portion <NUM> are provided on the entire surface of the base material portion <NUM>. Next, a laser is irradiated to a position on the base material portion <NUM> where the transmitting portion <NUM> is to be formed. The picture pattern portion <NUM> and the shielding portion <NUM> at the position where the laser is irradiated are removed. The position of the picture pattern portion <NUM> and the shielding portion <NUM>, which have been removed, becomes the transmitting portion <NUM>. In such a method of forming the transmitting portion <NUM>, the cost increases in proportion to the area to be irradiated with the laser.

Alternatively, the transmitting portion <NUM> may be formed as follows by using a photolithography technique. First, the picture pattern portion <NUM> and the shielding portion <NUM> are provided on the entire surface of the base material portion <NUM>. Next, a photoresist is applied to the side on which the picture pattern portion <NUM> and the shielding portion <NUM> are provided. After that, a photomask having holes at positions where the transmitting portion <NUM> is to be formed is provided on the photoresist. Ultraviolet rays are irradiated through the photomask. When irradiated with ultraviolet rays, the photoresist dissolves in a developer.

That is, the photoresist dissolves at the position where the transmitting portion <NUM> is to be formed during a development step. Next, the base material portion <NUM> is immersed in an etchant to remove the picture pattern portion <NUM> and the shielding portion <NUM> at the positions where the photoresist has been removed. The position of the picture pattern portion <NUM> and the shielding portion <NUM>, which have been removed, becomes the transmitting portion <NUM>. In such a method of forming the transmitting portion <NUM>, the cost increases in proportion to the size of the photomask used and the size of a ultraviolet irradiation device.

The method of forming the transmitting portion <NUM> described above is an example, and the transmitting portion <NUM> may be formed by another method.

As described above, the decorative sheet, the display system with a decorative sheet, and the display system with a panel according to the present embodiment are excellent in the visibility of a picture pattern of the decorative sheet.

Various changes can be made to the embodiment described above.

For example, the decorative sheet <NUM> includes the base material portion <NUM> in the embodiment described above. However, the base material portion <NUM> may be removed from the decorative sheet <NUM> by being peeled off in the manufacturing process or the like. In this case, the transmitting portion <NUM> may be formed as a through-hole in the decorative sheet <NUM>.

Further, as illustrated in <FIG>, the transmitting portion <NUM> is formed on the entire decorative sheet <NUM> in the embodiment described above. However, as illustrated in <FIG>, the transmitting portion <NUM> of the decorative sheet <NUM> may be formed only in the region facing the display surface <NUM> of the display device <NUM>. As the transmitting portion <NUM> is formed only in the region facing the display surface <NUM> of the display device <NUM>, it is possible to reduce the manufacturing cost of the decorative sheet.

Further, as illustrated in <FIG>, the picture pattern portion <NUM> of the decorative sheet <NUM> is arranged on the side from which the display device <NUM> with a panel is observed in the embodiment described above. However, as illustrated in <FIG>, the base material portion <NUM> of the decorative sheet <NUM> may be arranged on the side from which the display system <NUM> with a panel is observed. When the base material portion <NUM> of the decorative sheet <NUM> is arranged on the side from which the display device <NUM> with a panel is observed, it is less likely that foreign matters adhere to the transmitting portion <NUM> and obstruct image light.

Claim 1:
A decorative sheet (<NUM>), for facing the display surface of a display device, comprising
a picture pattern portion (<NUM>) and a plurality of transmitting portions (<NUM>) that are portions in which the picture pattern portion (<NUM>) is not formed, wherein
an aperture ratio, defined as the ratio of the area of the transmitting portions (<NUM>) to the total area of the decorative sheet (<NUM>), is <NUM>% or more and <NUM>% or less, and
each of the transmitting portions (<NUM>) is formed such that a distance between the transmitting portions (<NUM>) adjacent to each other is <NUM> or more and <NUM> or less, wherein,
when the transmitting portions are arranged in a grid pattern, the distance between the transmitting portions is defined as the shortest distance between edges of the adjacent transmitting portions, and,
when the transmitting portions are arranged in a mode other than a grid pattern, the distance between the transmitting portions is defined as the average distance between nearest edges of adjacent transmitting portions.