Injection molding method, injection-molded article, and display device

Abstract

To provide an injection molding method, an injection-molded article, and a display device capable of suppressing color tone change of a pattern associated with decoration of a light-transmissive decorative insert film.SOLUTION: In an injection molding method, resin 40 is injection-molded into molds 50A, 50B in a state where a light-transmissive decorative insert film 2 is inserted therein. On the back side of the light-transmissive decorative insert film 2 having a transmittance of 10% or more and 80% or less, a resin layer 3 is formed by injection molding. The resin layer 3 formed by injection molding is adjusted by adding pigment to transparent resin so that its transmittance becomes 40% or less. Accordingly, even if light irradiated from the surface of the light-transmissive decorative insert film 2 is reflected at the air layer on the back surface of the resin layer 3, the reflected light is reduced. Therefore, since the amount of light illuminating the light-transmissive decorative insert film 2 from the back side is reduced, it is possible to suppress thinning of the color tone of the decorated pattern.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to an injection molding method, an injection molded product, and a display device.

Background Art

[0002] Conventionally, as an injection molded product, one formed by injecting a molten material into a light-transmissive insert film is known (for example, see Patent Document 1). This injection molded product is used for decorating a center console. A driver can view an image displayed on a display device through the injection molded product.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, when the resin used for injection molding is to transmit light, a transparent resin such as acrylic, ABS, or polycarbonate is used. When the insert film is decorated with a light-transmissive decoration, the light-transmissive decorative insert film transmits light. When a layer that does not partially transmit light is provided under the decoration layer to form a display portion, when illuminating light from the back surface, the display portion can be displayed on the decoration layer with the light transmitted through the display portion. However, even when not illuminating light from the back surface, when light hits from the front, there has been a problem that the color tone of the decoration layer of the display portion changes, so that the display portion can be seen even when not displaying. Further, even when not providing a layer that does not transmit light, there has been a problem that the color tone of the pattern layer becomes lighter as a whole when light hits from the front.

[0005] The present invention is for solving the above-described problems, and an object thereof is to provide an injection molding method, an injection molded product, and a display device that can suppress a change in the color tone of a pattern related to the decoration of a light-transmissive decorative insert film.

Means for Solving the Problem

[0006] When the inventors of the present application injection-molded a transparent resin onto an insert film decorated with a pattern of visible light transmittance, they found that the light transmitted from the surface of the light-transmissive decorative insert film was reflected at the boundary with the air layer on the back side of the transparent resin, illuminating the light-transmissive decorative insert film from the back. Furthermore, the inventors of the present application found that such a phenomenon caused the pattern of the light-transmissive decorative insert film to become less visible due to the fading of the color tone of the pattern, or the color tone of the pattern differed between the part with the concealment layer and the part without the concealment layer, so that the presence of the display part was always visible and the design property was degraded, or when a display was installed behind the injection-molded product, the contrast of the image of the display device seen through the injection molding was reduced.

[0007] [1] As an injection molding method according to one aspect, the present invention prepares a light-transmissive decorative insert film having a visible light transmittance of 10% or more and 80% or less by decorating a film, prepares a resin having a visible light transmittance of 40% or less by adding a pigment to a transparent resin, inserts the light-transmissive decorative insert film into a mold, and injects the resin into the mold to mold an injection-molded product.

[0008] In this injection molding method, the resin is injection molded with a light-transmissive decorative insert film inserted into the mold. Therefore, a resin layer formed by injection molding is formed on the back side of the light-transmissive decorative insert film having a transmittance of 10% or more and 80% or less. The resin layer formed by injection molding is adjusted by adding a pigment to a transparent resin so that the transmittance becomes 40% or less. Therefore, even if the light irradiated from the surface of the light-transmissive decorative insert film is reflected by the air layer on the back surface of the resin layer, the reflected light is reduced. Therefore, since the amount of light illuminating the light-transmissive decorative insert film from the back side is reduced, it is possible to suppress the color tone of the decorated pattern from becoming lighter. Further, by lowering the transmittance of the resin for injection molding, the base concealability is enhanced, and even if there is a display device inside, its presence can be concealed. Further, by making the resin for injection molding into a smoke resin, it is also possible to eliminate the concealment layer and the coloring layer of the light-transmissive decorative insert film itself.

[0009] [2] In the injection molding method of [1] above, the pigment may be carbon black. In this case, by adding an appropriate amount of carbon to the transparent resin, the resin for injection molding can be made into a gray smoke with a transmittance of 40% or less.

[0010] [3] In the injection molding method of [1] or [2] above, the pigment may be an inorganic or organic coloring pigment. Thereby, by coloring the smoke resin, the color tone of the light-transmissive decorative insert film can be controlled.

[0011] [4] As another aspect, the present invention relates to an injection molded product. This injection molded product is molded by the injection molding method described in any one of [1] to [3] above. In this case, it is possible to provide an injection molded product in which the color tone of the pattern of the light-transmissive decorative insert film does not become lighter due to back surface reflection.

[0012] [7] The display device includes the injection molded product of [4] above and a display device. In this case, the display device can be concealed while suppressing a decrease in the color tone of the pattern of the light transmissive decorative insert film.

Advantages of the Invention

[0013] According to the present invention, it is possible to provide an injection molding method, an injection molded product, and a display device that can suppress a change in the color tone of a pattern related to the decoration of a light transmissive decorative insert film.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Modes for Carrying Out the Invention

[0015] Specific examples of an injection molding method, an injection molded product, and a display device according to an embodiment of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these examples, and is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. In the following description, the same reference numerals are given to the same elements in the description of the drawings, and redundant descriptions are omitted.

[0016] FIG. 1 is a cross-sectional view schematically showing an injection molded product 1 according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a display device 100 according to the present embodiment. As shown in FIG. 1, the injection molded product 1 includes a light-transmissive decorative insert film 2 and a resin layer 3. As shown in FIG. 2(a), the display device 100 includes the injection molded product 1 and a display device 4.

[0017] The injection molded product 1 is provided in front of the display device 4 which is a light source (between the viewer and the display device 4). The display device 100 is configured by hiding the display device 4 with the injection molded product 1. The injection molded product 1 has total light transmittance. Therefore, when the power of the display device 4 is ON, the viewer can visually recognize the light from the display device 4 transmitted through the injection molded product 1, and when the power of the display device 4 is OFF, the viewer can visually recognize the pattern expressed by the injection molded product 1. In the injection molded product 1, the outer peripheral portion 1b on the outer peripheral side rather than the central portion 1a near the center where the display device 4 is disposed is bent so as to go toward the back surface side (the display device 4 side) as it extends to the outer peripheral side. In the present embodiment, the outer peripheral portion 1b is bent so as to be bent and inclined with respect to the central portion 1a, but it may be bent so as to be curved.

[0018] The light-transmissive decorative insert film 2 is a sheet for expressing a pattern. The visible light transmittance of the light-transmissive decorative insert film 2 is preferably 10% or more and 80% or less. In addition, when the concealment layer 7 described later is not provided on the light-transmissive decorative insert film 2, the transmittance may be 70% or more. Since the visible light transmittance of the light-transmissive decorative insert film 2 is 10% or more, it becomes easier for the light of the display device (see FIG. 4) to pass through. The higher the transmittance of the light-transmissive decorative insert film 2, the better because it allows light from the back surface to pass through. Note that the transmittance in this specification means, for example, the value of the visible light transmittance measured using a spectrophotometer (for example, UV-2100, manufactured by Shimadzu Corporation).

[0019] The light-transmissive decorative insert film 2 includes a film 5 and a decorative printing layer 8. The light-transmissive decorative insert film 2 is formed by decorating the film 5. The decorative printing layer 8 is formed by performing printing on the film 5. FIG. 3 is a cross-sectional view showing an example of the layer structure of the light-transmissive decorative insert film 2. As shown in FIG. 3, as shown in FIG. 3, the decorative printing layer 8 may have a pattern layer 6 and a concealment layer 7. However, the structure of the light-transmissive decorative insert film 2 is not particularly limited as long as it is a decorative film having light transmittance. For example, the concealment layer 7 of the light-transmissive decorative insert film 2 itself may be eliminated by using a resin layer 3 instead of the concealment layer. Note that the concealment layer 7 may be a color film with holes instead of a layer formed by printing.

[0020] The film 5 is a substrate having visible light transmittance. The film 5 is a formable material. For the film 5, materials such as acrylic, acrylic / polycarbonate, etc. may be adopted which have high formability and do not crack or break during forming, but the material is not particularly limited as long as it has formability. The thickness of the film 5 is, for example, 25 μm to 250 μm. In addition, if necessary, a hard coat layer, an anti-fingerprint layer, an anti-reflection layer, etc. may be provided on the surface side (the side opposite to the pattern layer 6) of the film 5. However, for the surface layer, a material that does not crack and stretches during forming is used. The functional layer on the surface side may also be an after-cure type that is cured by performing UV exposure after forming. Light-transmissive decoration printing is performed on the back surface (the surface on the side of the pattern layer 6) of the film 5.

[0021] The pattern layer 6 is a layer on which the pattern expressed by the light-transmissive decorative insert film 2 is formed. The pattern of the pattern layer 6 is the pattern that appears on the surface of the decorative sheet when the power of the display device 4 is OFF, and for example, a wood grain pattern or an abstract pattern may be adopted. The pattern layer 6 may be formed by printing on the film 5. The printing method is not limited, such as gravure printing, inkjet printing, screen printing, offset printing, etc. The material of the decorative ink used for printing may be an inorganic pigment, an organic pigment, an interference pigment, etc., and the material is not limited. The thickness of the pattern layer 6 is, for example, 1 μm to 100 μm.

[0022] The concealment layer 7 is a layer that conceals the display device 4 when the power of the display device 4 is OFF and determines the color tone of the pattern. When the pattern layer 6 uses an interference pigment, black or gray is used for the concealment layer 7 to improve color development, but when pigments such as inorganic pigments are used, using black or gray makes the pattern difficult to see. Therefore, it is preferable to use a light color such as white for the concealment layer 7. When the pattern is a wood grain, the concealment layer 7 can change the color tone with a brown-based color. It is preferable to keep the underlying concealment property of the concealment layer to the minimum necessary and increase the transmittance.

[0023] Since the concealment layer 7 conceals the display device 4 together with the resin layer 3 described later, the concealment property of the concealment layer 7 itself may be kept low. The concealment layer 7 may be formed, for example, by printing a solid layer on the pattern layer 6. As the concealment layer 7, for example, a white solid layer may be printed. The white solid layer has the effect of controlling the color tone of the pattern and preventing the pattern from being difficult to see by sinking into the underlying black. The concealment property may be reduced by reducing the printing density of the white solid printing and printing thinly. The concealment layer 7 may be formed, for example, by printing a black solid layer. The black solid layer has the effect of making the color development of the interference pigment easier to see and concealing the underlying layer. The concealment layer of the black solid layer may have its underlying concealment property reduced by reducing the printing density and printing thinly, or the concealment layer itself may be eliminated. The printing method is not limited, such as gravure printing, inkjet printing, screen printing, offset printing, etc. Note that a further concealment layer may be partially formed on the concealment layer 7, and a portion with permeability and a portion without permeability may be provided. The printing density at the boundary between the portion without permeability and the portion with permeability may be changed in a gradient manner so that there is no clear difference. The concealment layer 7 may be a layer formed by printing, or a colored film or a colored sheet. Similarly, a further concealment layer may be partially formed on the resin layer 3.

[0024] Note that, by having the resin layer 3 substitute for a color former that determines the color tone of the concealment layer and the pattern, the concealment layer and the color solid layer that control the color tone may be eliminated from the configuration of the light-transmissive decorative insert film 2. The concealment layer 7 may be made by laminating a colored film instead of printing. The colored film has higher light transmittance as its film thickness is thinner. There may be a top coat layer on the surface of the light-transmissive decorative insert film 2. There may be embossing on the surface of the film 5. The printing may be either front printing or back printing.

[0025] Here, an example of the specific structure of the pattern layer 6 will be described with reference to FIG. 4. The pattern layer 6 shown in FIG. 4 includes a first color pattern layer 10 provided on one surface 4a of the film 5, and a second color pattern layer 20 provided on the first color pattern layer 10.

[0026] The first color pattern layer 10 can be provided on the surface 4a, for example, by screen printing, inkjet printing, gravure printing, or offset printing. As shown in FIG. 4, the first color pattern layer 10 is composed of a plurality of first color dots 11. Here, the "dot" means a point that constitutes a printed image, and its shape is not limited to a circular shape, and it may be a rectangular shape, a polygonal shape, or other shapes. Each of the plurality of first color dots 11 includes a first color binder 12 and a plurality of first color pigment chips 13 dispersed inside the first color binder 12. The content rate of the plurality of first color pigment chips 13 is, for example, in the range of 0.5 parts by weight or more and 20 parts by weight or less when the first color binder 12 is 100 parts by weight.

[0027] Examples of the first color binder 12 include vinyl resins, acrylic resins, thermoplastic urethane resins, polyester resins, and polycarbonate resins. The thickness of the first color pattern layer 10 is, for example, 1 μm to 10 μm. Note that a curing agent may be contained in the first color pattern layer 10. In this case, the heat resistance of the first color pattern layer 10 and the adhesion of the first color pattern layer 10 to the film 5 can be improved.

[0028] In this embodiment, the plurality of first color pigment chips 13 are first interference pigments 14a and 14b of a plurality of colors that generate different interference lights. Each of the first interference pigments 14a and 14b is composed of a thin sheet (not shown) having visible light transparency and a metal oxide film (not shown) covering the thin sheet. Among the incident light from the film 5 side to the first color pattern layer 10, the light reflected on the surface of the metal oxide film and the light passing through the metal oxide film and reflected on the surface of the thin sheet interfere with each other to generate interference light. By adjusting the film thickness of the metal oxide film and the refractive index of the metal oxide film, interference light having a desired wavelength can be generated.

[0029] In this embodiment, each of the first interference pigments 14a and 14b is titanium dioxide-coated mica. The particle size range of the titanium dioxide-coated mica includes, for example, a range of 25 μm or more and 60 μm or less. Here, the "particle size" means the longest diameter of the particle cross-section. The flakes constituting the first interference pigments 14a and 14b may be other than mica, and may be, for example, silica, alumina, glass, or polysilicate. The metal oxide film constituting the first interference pigments 14a and 14b may be other than titanium dioxide, and may be, for example, zirconium oxide, zinc oxide, iron oxide, or tin oxide.

[0030] When incident light E is incident on the first color pattern layer 10 from each of the first interference pigments 14a and 14b, different first interference lights 15a and 15b are generated respectively. That is, the wavelengths of the first interference lights 15a and 15b are different from each other. Thereby, the first interference pigments 14a and 14b exhibit color mixing. Each of the first interference pigments 14a and 14b is, for example, a red interference pigment (red pearl pigment) and a gold interference pigment (gold pearl pigment) respectively. In this case, each of the first interference lights 15a and 15b exhibits red and gold respectively. The blending amounts of the first interference pigments 14a and 14b may be the same or different from each other.

[0031] The second color pattern layer 20 can be provided on the first color pattern layer 10 by, for example, screen printing, inkjet printing, gravure printing, or offset printing. As shown in FIG. 4, the second color pattern layer 20 is composed of a plurality of second color dots 21. Here, the "dot" means a point that is an element constituting a printed image, and its shape is not limited to a circle, and may be a rectangle, a polygon, or other shapes. Each of the plurality of second color dots 21 includes a second color binder 22 and a plurality of second color pigment chips 23 dispersed inside the second color binder 22. The content rate of the plurality of second color pigment chips 23 is, for example, within a range of 0.5 parts by weight or more and 20 parts by weight or less when the second color binder 22 is 100 parts by weight.

[0032] Examples of the binder 22 for the second color include vinyl resins, acrylic resins, thermoplastic urethane resins, polyester resins, polycarbonate resins, and the like. The thickness of the second color pattern layer 20 is, for example, 1 μm to 10 μm. The second color pattern layer 20 may contain a curing agent. In this case, the heat resistance of the second color pattern layer 20 and the adhesion of the second color pattern layer 20 to the first color pattern layer 10 can be improved.

[0033] In this embodiment, the plurality of second color pigment chips 23 are second interference pigments 24 that generate interference light of a single color different from the mixed color indicated by the first interference pigments 14a and 14b. The second interference pigment 24 is composed of a thin sheet (not shown) having visible light transparency and a metal oxide film (not shown) covering the thin sheet. Among the incident light from the film 5 side to the second color pattern layer 20, the light reflected on the surface of the metal oxide film and the light passing through the metal oxide film and reflected on the surface of the thin sheet interfere with each other to generate interference light. By adjusting the film thickness of the metal oxide film and the refractive index of the metal oxide film, interference light having a desired wavelength can be generated.

[0034] In this embodiment, the second interference pigment 24 is titanium dioxide-coated mica. The particle size range of the titanium dioxide-coated mica includes, for example, a range of 25 μm or more and 60 μm or less. Here, the "particle size" means the longest diameter of the particle cross section. The thin sheet constituting the second interference pigment 24 may be other than mica, and may be, for example, silica, alumina, glass, or poly silicate. The metal oxide film constituting the second interference pigment 24 may be other than titanium dioxide, and may be, for example, zirconium oxide, zinc oxide, iron oxide, or tin oxide.

[0035] When incident light E is incident on the second color pattern layer 20 from the second interference pigment 24, single-color second interference light 25 is generated. Thereby, the second interference pigment 24 exhibits a single color. The second interference pigment 24 may be an interference pigment that generates second interference light 25 of a single color different from the mixed color indicated by the first interference pigments 14a and 14b. For example, it may be a green interference pigment (green pearl pigment). In this case, the second interference light 25 exhibits green.

[0036] In the pattern layer 6, a pattern is expressed by additive color mixing of the first interference lights 15a and 15b generated by the first interference pigments 14a and 14b and the second interference light 25 generated by the second interference pigment 24.

[0037] As shown in FIG. 1, the resin layer 3 has a function of attenuating light from the front side of the viewing point that passes through the light-transmissive decorative insert film 2. The resin layer 3 is disposed on the back surface of the light-transmissive decorative insert film 2. In the display device 100, the resin layer 3 is disposed on the surface side of the display device 4. The resin layer 3 is a colored transparent resin molded layer having a predetermined transmittance. The transmittance of the resin layer 3 may be 10% or more, and may be further 18% or more. Also, the transmittance of the resin layer 3 may be 40% or less, and may be further 20% or less. For enhancing the substrate concealment property, the transmittance of the resin layer 3 is preferably 20% or less. The lower the transmittance, the more the back surface reflected light can be reduced. Therefore, when the brightness of the display device 4 installed on the back surface is high, it is better to lower the transmittance of the resin layer 3.

[0038] The resin layer 3 is a layer formed by performing injection molding with the light-transmissive decorative insert film 2 inserted into a mold. The resin layer 3 is composed of a smoke resin having a specified transmittance by adding an appropriate amount of pigment to a transparent resin. As the resin for injection, resin pellets with a pigment pre-added and the transmittance adjusted may be used. By making the resin layer 3 smoky, the amount of transmitted light reflected at the boundary with the air layer on the back side of the injection-molded resin layer 3 that illuminates the pattern of the light-transmissive decorative insert film 2 from the back can be reduced.

[0039] The transparent resin of the resin layer 3 may be made of any transparent resin such as acrylic, polycarbonate, or ABS. The pigment may be carbon black. Alternatively, the pigment may be an inorganic or organic coloring pigment. For example, it is preferable to make the resin colored with carbon black into a gray smoke, but in order to control the color tone of the pattern, a brown pigment may be added to make the resin colored into a brown smoke. However, when making it into a smoke, depending on the pigment, when viewed through the liquid crystal screen, the color tone of the liquid crystal may change, so it is better to adjust RGB. When the liquid crystal image looks blue, it is advisable to lower the gain and bias of B. When it looks red, it is advisable to lower the gain and bias of R. Note that the pigment is preferably inorganic, but it may be organic or a dye may be used. Since the resin transmittance of the resin layer 3 depends on the thickness of the resin, measure the transmittance of the actually injected smoke resin and put an appropriate amount of pigment into the injection resin so that the specified transmittance is achieved.

[0040] The resin layer 3 is colored. The color of the resin layer 3 is not particularly limited, and any color may be adopted. When displaying the image of the display device 4, the color is preferably gray. Since the resin layer 3 can be of various colors and can be made into the color of a preferred wall, the color is not limited to the above. The resin layer 3 may control the color tone of the light-transmissive decorative insert film 2 according to the color of the resin layer 3. For example, at the timing when the display device 4 is OFF, the pattern of the pattern layer 6 of the light-transmissive decorative insert film 2 can be visually recognized both in the part where the display device 4 is present and the part where it is not. At this time, the color tone of the pattern of the pattern layer 6 is controlled by the color of the resin layer 3. For example, if the color of the resin layer 3 is brown and the pattern of the pattern layer 6 is wood grain, wood grain with a brown tint can be visually recognized.

[0041] The lower the transmittance of the resin layer 3, the greater the effect of reducing the reflected light. However, in consideration of the brightness of the display device 4, etc., it is preferable to optimize the transmittance of the resin layer 3. When changing the thickness of the resin layer 3, the transmittance of that part changes, so it is preferably constant, but the thickness may be changed. When the color tone changes by changing the thickness, it is preferable to attach a black sheet to the back side or paint it to match the color tone. When the resin layer 3 affects the color tone of the image of the display device 4, it is preferable to adjust the color tone by adjusting the RGB gain and bias of the display device 4. Depending on the color tone of the resin layer 3, by adjusting the RGB bias and gain of the display device 4 of the display device 100, white display may appear whiter through the resin layer 3.

[0042] Next, with reference to FIGS. 5 and 6, an injection molding method according to the present embodiment will be described. FIG. 5 is a process diagram showing an example of the procedure of the injection molding method. FIG. 6 is a schematic diagram showing the procedure of the injection molding method. As shown in FIG. 5, first, by decorating the film 5, a light-transmissive decorative insert film 2 having a visible light transmittance of 10% or more and 80% or less is prepared (step S10). By adding a pigment to a transparent resin, a resin 40 for injection molding having a visible light transmittance of 40% or less (see FIG. 6(e)) is prepared (step S20). For example, acrylic pellets for injection molding and carbon pigment are mixed, melted with heat while stirring, and an acrylic resin for smoke is produced. At this time, the amount of pigment is adjusted so as to obtain a specified transmittance.

[0043] Next, the light-transmissive decorative insert film 2 is molded (step S30). In step S30, the light-transmissive decorative insert film 2 is molded into a desired shape for insert molding. Specifically, first, as shown in FIG. 7(a), the flat light-transmissive decorative insert film 2 is heated by the heater 41. Next, as shown in FIG. 7(b), the heated light-transmissive decorative insert film 2 is preformed by vacuum pressure molding. As a result, the heated light-transmissive decorative insert film 2 assumes a shape corresponding to the molding surface of the mold 42. Here, the molded light-transmissive decorative insert film 2 is deformed so as to form two ridge portions. As shown in FIG. 7(c), trimming is performed to cut away unnecessary portions from the molded light-transmissive decorative insert film 2.

[0044] Next, as shown in FIG. 5, the light-transmissive decorative insert film 2 is inserted into the injection molding molds 50A and 50B (step S40). Specifically, as shown in FIG. 6(d), the light-transmissive decorative insert film 2 is inserted into the molding space between the mold 50A and the mold 50B. A flow path 51 for supplying the resin 40 for injection molding is formed in the back mold 50A. The flow path 51 opens at the molding surface of the mold 50A.

[0045] Next, as shown in FIG. 5, the injection molded product 1 is molded by injecting the resin 40 into the molds 50A and 50B into which the light-transmissive decorative insert film 2 has been inserted (step S40). As shown in FIG. 6(e), the resin 40 is injected from the flow path 51 of the mold 50A against the back surface of the light-transmissive decorative insert film 2. As a result, the resin layer 3 is formed on the back surface side of the light-transmissive decorative insert film 2 by injection molding. When the molding is completed, as shown in FIG. 6(f), the molds 50A and 50B are opened and the injection molded product 1 is taken out.

[0046] For example, as the resin 40 for injection molding, the transmittance of the smoke acrylic resin is adjusted to 20%, and the transmittance of the injection molded product 1 injection molded on the light transmissive decorative insert film 2 with a transmittance of 50% is 10%. After the injection molding is completed, the back side of the injection molded product 1 except for the window portion 35 for the display device 4 may be painted black. At this time, the injection molded product 1 can cover the display device 4 (see Fig. 2(a)) and conceal the display device 4.

[0047] Next, the operation and effects of the injection molding method, the injection molded product 1, and the display device 100 according to the present embodiment will be described.

[0048] First, with reference to Figs. 7 and 8, the injection molded product 200 and the display device 300 according to the comparative example will be described. As shown in Fig. 7, the injection molded product 200 according to the comparative example includes a light transmissive decorative insert film 2 and a transparent resin layer 32, and does not include a resin layer 3. Different from the resin layer 3, the transparent resin layer 32 has not been adjusted in transmittance by adding a pigment, and the transmittance is 93〇〇%. As shown in Fig. 8, the display device 300 according to the comparative example is covered with the injection molded product 200 over the display device 4. A black printing portion 9 in which portions other than the window portion 35 for the display device 4 are painted black is formed at the boundary between the light transmissive decorative layer insert film 2 and the transparent resin layer 32.

[0049] In the injection molded product 200, as shown in FIGS. 7 and 8, when the back surface of the transparent resin layer 32 is an air layer, the incident light LIN incident from the front surface of the light transmissive decorative insert film 2 is reflected at the back surface of the transparent resin layer 32. As a result, the reflected light LOUT1 at the air layer interface illuminates the light transmissive decorative insert film 2 from the back surface, and the color tone of the light transmissive decorative insert film 2 becomes lighter. Such a phenomenon causes the pattern to become less visible due to the lighter color tone of the pattern of the light transmissive decorative insert film 2, or causes a decrease in the contrast of the image of the display device 4 viewed through the injection molded product 200. Further, when the display device 4 is OFF, the pattern layer can be seen on the surface of the injection molded product 200. However, in the case of the transparent resin layer 32, since the reflected light LOUT1 from the display device 4 is brighter than the reflected light LOUT2 from the black printed portion 9, the color tone of the pattern in the window portion 35 appears lighter, and even when the display device 4 is not lit, the presence of the window portion 35 can be seen (see FIG. 8(b)).

[0050] On the other hand, in the injection molding method according to the present embodiment, the resin 40 is injection molded with the light transmissive decorative insert film 2 inserted into the molds 50A and 50B. Therefore, the resin layer 3 by injection molding is formed on the back side of the light transmissive decorative insert film 2 having a transmittance of 10% or more and 80% or less. The resin layer 3 by injection molding is adjusted by adding a pigment to a transparent resin so that the transmittance becomes 40% or less. Therefore, even if the light irradiated from the front surface of the light transmissive decorative insert film 2 is reflected by the air layer on the back surface of the resin layer 3, the reflected light is reduced. Therefore, since the amount of light illuminating the light transmissive decorative insert film 2 from the back side is reduced, it is possible to suppress the color tone of the decorated pattern from becoming lighter. Further, by reducing the transmittance of the resin for injection molding, the substrate concealment property is enhanced, and even if there is a display device 4 inside, its presence can be concealed. Further, by making the resin for injection molding into a smoke resin, it is also possible to eliminate the concealment layer and the coloring layer of the light transmissive decorative insert film 2 itself.

[0051] As shown in Fig. 2(a), when the resin layer 3 is used, the difference in brightness between the reflected light LOUT1 at the window portion 35 corresponding to the display device 4 and the reflected light LOUT2 at the black printed portion 9 is small. Therefore, since the color tone of the window portion 35 does not become bright (see Fig. 2(b)), the presence of the window portion 35 when the display device 4 is OFF can be concealed. Further, in the case of an image display device such as the display device 4, a decrease in the contrast of the video displayed on the surface of the injection molded article 1 can be prevented.

[0052] In the injection molding method, the pigment may be a mixture of pigments of a plurality of colors or a single-color pigment. In order to eliminate color variations, the raw material is preferably single-color and black. The single-color pigment may be carbon black. In this case, by adding an appropriate amount of carbon to the transparent resin, the resin 40 for injection molding can be made into a gray smoke with a transmittance of 40% or less.

[0053] In the injection molding method, the pigment may be an inorganic or organic coloring pigment. Thereby, by coloring the smoke resin, the color tone of the light-transmissive decorative insert film 2 can be controlled.

[0054] The injection molded article 1 according to the present embodiment is molded by the above-described injection molding method. In this case, it is possible to provide an injection molded article 1 in which the color tone of the pattern of the light-transmissive decorative insert film 2 does not become thin due to back reflection.

[0055] The display device 100 includes the above-described injection molded article 1 and the display device 4. In this case, the display device 4 can be concealed while suppressing the thinning of the color tone of the pattern of the light-transmissive decorative insert film 2.

[0056] In addition, when the pattern layer 6 of the light-transmissive decorative insert film 2 is formed by printing using an interference pigment, the interference pigment itself has no color, and the light transmitted from the back surface is not affected by the color of the pattern. Therefore, the image of the display device 4 on the back surface can be transmitted without being covered by the color of the pattern. Even if an interference pigment is not used, the pattern layer 6 can have light transmissivity as long as the concealment layer 7 does not block light. However, since the pattern covers the image, the image cannot be projected beautifully. However, designs such as switches and numerical and character information have no problem with visibility even if the pattern covers them. The ink material of the pattern layer 6 is preferably selected according to the application. In the case of an interference pigment, in order to improve color development, the concealment layer 7 may be formed in gray-scale, but the concealment layer may be substituted by making the resin layer 3 resin of the injection molding into gray-scale.

[0057] The injection molded article, display device, and display method according to the present invention are not limited to the above-described embodiments, and various other modifications are possible.

[0058] For example, the second color pattern layer may include a plurality of colors of first interference pigments that generate different first interference lights from each other, and the first color pattern layer may include a second interference pigment that generates a single-color second interference light different from the mixed color shown by the plurality of first interference pigments. Further, in each of the above embodiments, the first color pigment chip was a two-color first interference pigment, but the first color pigment chip may be a three-color or more first interference pigment.

[0059] The shape of the injection molded article is not limited to the shape shown in FIG. 1. For example, the back surface of the resin layer 3 may be configured in a flat shape without bending.

Description of Reference Numerals

[0060] 1... Injection molded article, 2... Light-transmissive decorative insert film, 3... Resin layer, 4... Display device, 40... Resin, 50A, 50B... Mold, 100... Display device.

Claims

1. By decorating the film, a light-transmissive decorative insert film having a visible light transmittance of 10% or more and 80% or less is prepared. By adding a pigment to a transparent resin, a resin having a visible light transmittance of 40% or less is prepared. An injection molding method of molding an injection molded product by inserting the light-transmissive decorative insert film into a mold and injecting the resin into the mold.

2. The injection molding method according to claim 1, wherein the pigment is carbon black.

3. The injection molding method according to claim 1, wherein the pigment is an inorganic or organic coloring pigment.

4. An injection molded product molded by the injection molding method according to any one of claims 1 to 3.

5. A display device including the injection molded product according to claim 4 and a display device.

Images