Method for manufacturing panel element

Abstract

A method for manufacturing the panel element (1) according to an aspect of the present invention includes: a process of printing a printed layer (4a) formed of an ink that does not transmit light on a front side of a resin sheet (3); a process of superimposing and printing a printed layer (4b) on an upper surface of the printed layer (4a) to form a laminated printed layer (4); and a process of irradiating the laminated printed layer (4) with laser light on a front side thereof to remove a part of the laminated printed layer (4) and to form a hole portion having a vertical end face in the laminated printed layer (4).

Claims

1. A method for manufacturing a panel element including a transparent sheet having a front side printed, comprising: a process of printing a first printed layer formed of an ink that does not transmit light on the front side of the transparent sheet; a process of superimposing and printing a second printed layer on an upper surface of the first printed layer to form a laminated printed layer; a process of printing a third printed layer formed of an ink that does not absorb laser light on a back side of the transparent sheet; an attachment process of attaching the transparent sheet having the laminated printed layer to a resin substrate constituting the panel element; and a process of irradiating the laminated printed layer with laser light on a front side thereof to remove a part of the laminated printed layer and to form a hole portion having a vertical end face in the laminated printed layer, at a position corresponding to the third printed layer of the transparent sheet after the attachment process.

2. The method for manufacturing the panel element according to claim 1, wherein an ink that absorbs the laser light is used for the first printed layer.

3. The method for manufacturing the panel element according to claim 1, wherein the second printed layer includes multiple printed layers.

4. The method for manufacturing the panel element according to claim 1, wherein the third printed layer includes a colored layer colored in a predetermined color and a white layer.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a front view of a panel element;

(2) FIG. 2 is a cross-sectional view of the panel element taken along line

(3) FIG. 3A to FIG. 3C are views for explaining a method for manufacturing the panel element (a cross-sectional portion taken along line II-II); and

(4) FIG. 4A to FIG. 4C are views for explaining a method for manufacturing the panel element (a cross-sectional portion taken along line IV-IV).

DETAILED DESCRIPTION

(5) Hereinafter, an embodiment of a panel element according to an aspect of the present invention is described.

(6) FIG. 1 is an overall structure of a panel element according to an aspect of the present invention. A panel element 1 is manufactured by so-called film insert molding, in which a decoration is printed on at least a front side of a resin sheet 3, and then pressure is applied to the resin sheet 3 to integrate the resin sheet 3 with a molded resin portion 2. The panel element 1 is used, for example, as an interior decorative part for a vehicle.

(7) The molded resin portion 2 is a plastic plate element having a thickness of about 3 mm, and a shallow recess matching the shape of the resin sheet 3 after a forming process is formed on a surface of the molded resin portion 2. In addition, a back surface of the molded resin portion 2 has a side plate having a height of about 15 mm so as to house a light source (LED substrate) which will be described below. The molded resin portion 2 is preferably a transparent or translucent material through which light from a light source passes.

(8) The resin sheet 3 is a light-transmissive film such as polycarbonate (PC), a polyethylene terephthalate resin (PET), a polymethyl methacrylate resin (PMMA), an acrylic, a multilayer sheet of polycarbonate and acrylic, or polypropylene. Although details are described below, the thickness of the resin sheet 3 is preferably 0.5 mm or less.

(9) A laminated printed layer 4 printed by high definition screen printing is formed on a front side of the resin sheet 3. The laminated printed layer 4 includes multiple printed layers. FIG. 1 illustrates that a woodgrain tone decoration is drawn on a surface of the panel element 1. The laminated printed layer 4 is formed by superimposing two to five printed layers such as brown printed layers and woodgrain fine lines printed layers. Note that the decoration is not limited to a woodgrain tone, but can be various decoration such as a carbon tone, piano black (gloss black), or the like.

(10) In addition, the panel element 1 has graphics 5a, 5b1, and 5b2 which are consisting of punched characters or punched patterns on a surface thereof. Although details are described below, after completion of the laminated printed layer 4, it is removed in a shape of a desired graphic by being scaned with laser light of the laser marking device (for example, light of Nd: YAG laser having a wavelength of 1,064 m). As a result, hole portions of the graphics 5a, 5b1, and 5b2 are formed in the laminated printed layer 4.

(11) In the graphic 5a, only at an outline of a four-leaf mark a hole portion is formed, and light of a light source arranged on a back side of the molded resin portion 2 passes therethrough. In addition, a printed layer is printed on a back side of the resin sheet 3 such that the graphics 5b1 and 5b2 have different patterns or colors from each other.

(12) In the graphic 5a through which light passes, no printed layer is provided on the back side of the resin sheet 3. However, when it is not desired to directly irradiate a front side of the panel element 1 with light, a white printed layer may be provided on the back side of the resin sheet 3.

(13) Next, FIG. 2 illustrates a cross-sectional view of the panel element 1 of FIG. 1 taken along line II-II.

(14) In the panel element 1, the resin sheet 3 which has been subjected to a forming process by pneumatic forming or the like is attached to a front side of the molded resin portion 2. The laminated printed layer 4 on a front side of the resin sheet 3 includes a printed layer 4a (the first printed layer according to an aspect of the present invention) through which light from a light source 6 does not pass, and printed layers 4b and 4c (the second printed layer according to an aspect of the present invention) mainly constructing a decoration. In a case where the decoration has a single color (in particular, black type), it can be constructed with only the printed layer 4a, but usually at least two or more printed layers are superimposed to construct a decoration.

(15) In FIG. 2, a portion where the laminated printed layer 4 is removed is the graphic 5a (outline of the four-leaf mark) in FIG. 1. In spite of the light source 6 is arranged on the back side of the molded resin portion 2, light of the light source 6 is emitted from the portion of the graphic 5a to the front side of the molded resin portion 2 because the molded resin portion 2 and the resin sheet 3 are light-transmissive materials.

(16) Next, with reference to FIGS. 3A to 3C, a method for manufacturing a cross-sectional portion of the panel element 1 of FIG. 1 taken along line II-II will be described. Note that the cross section of the molded resin portion 2 is omitted in the following description.

(17) As illustrated in FIG. 3A, the laminated printed layer 4 is formed with screen printing on the front side of the resin sheet 3 from a lower layer in order of the printed layers 4a, 4b, and 4c. The printed layer 4a is a layer of a black pigment containing an ink that easily absorbs laser light (Nd: YAG laser, CO.sub.2 laser, or the like) of a laser marking device, for example, carbon black. In addition, by making the printed layer 4a a black layer, a light shielding effect can also be obtained.

(18) The printed layers 4b and 4c are layers constructing a decoration of the panel element 1. For example of woodgrain tone decoration, the printed layer 4b is a brown woodgrain layer, and the printed layer 4c is a layer with woodgrain fine lines. In a case of forming a woodgrain tone decoration, actually, it is necessary to superimpose five or more printed layers. However, here a simplified three-layer structure is used for the sake of explanation.

(19) Next, as illustrated in FIG. 3B, in order to draw the graphic 5a, the laminated printed layer 4 is irradiated with laser light from the front side thereof. As a result, the printed layers 4b and 4c which are upper layers are melted by heat of the laser light. In addition, when the laser light reaches the printed layer 4a, the laser light is absorbed, and the printed layer 4a is removed (ablated) by a chemical reaction.

(20) Thereafter, as illustrated in FIG. 3C, the printed layers 4b and 4c are destroyed in accordance with removal of the printed layer 4a. Then, the laminated printed layer 4 is scanned with laser light to remove a part of the laminated printed layer 4 in the shape of the graphic 5a. At this time, by narrowing the diameter of the laser light, an extremely small hole portion can be formed. Therefore, an end face of the hole portion can be vertical.

(21) If the end face of the hole portion is not vertical and the hole portion of the printed layer 4c is smaller than the hole of each of the printed layers 4a and 4b, a portion through which the light of the light source 6 passes is narrow. In addition, a portion protruding toward the center of the hole from the end face of the hole of each of the printed layers 4a and 4b in the printed layer 4c (having a thickness of 3 to 6 m) can not shield the light completely. The incomplete light shielding area blur graphics. However, in the manufacturing method according to an aspect of the present invention, end faces of the holes of the printed layers 4a, 4b, and 4c are aligned vertically. Therefore, incomplete light shielding area does not exist in a peripheral portion of the graphic 5a, and a contour of the graphic 5a becomes clear.

(22) Next, with reference to FIGS. 4A to 4C, a method for manufacturing a cross-sectional portion of the panel element 1 of FIG. 1 taken along line IV-IV will be described. Also hereinafter, the cross section of the molded resin portion 2 is omitted.

(23) As illustrated in FIG. 4A, the laminated printed layer 4 is formed with screen printing on the front side of the resin sheet 3 from a lower layer in order of the printed layers 4a, 4b, and 4c. Also here, the printed layer 4a is a layer of ink that easily absorbs laser light, and the printed layers 4b and 4c are layers constructing a decoration of the panel element 1.

(24) In addition, a back surface printed layer 7 is formed with screen printing on the back side of the resin sheet 3 from a lower layer (layer in contact with the resin sheet 3) side in order of printed layers 7a and 7b (the third printed layer according to an aspect of the present invention). This is because if a printed layer for graphics is superimposed and printed on the front side of the resin sheet 3 (upper surface of the printed layer 4c), only this portion becomes convex to deteriorate an appearance.

(25) For example, in the back surface printed layer 7, the printed layer 7a is a red layer (an example of the colored layer according to an aspect of the present invention), and the printed layer 7b is a white layer (the white layer according to an aspect of the present invention). In this way, by superimposing three to four printed layers, it is possible to draw a pattern, a mark, or the like. Note that the back surface printed layer 7 may include only the printed layer 7a having a predetermined color.

(26) Here, the printed layers 7a and 7b are layers that do not absorb laser light of the laser marking device, that is, layers of an ink not deteriorated or destroyed by the laser light. As the ink of the white layer, for example, a pigment containing titanium oxide is used.

(27) Next, as illustrated in FIG. 4B, in order to draw the graphic 5b2, the laminated printed layer 4 is irradiated with laser light on a front side thereof. As a result, at the time of removal (ablation) of the printed layer 4a, the printed layers 4b and 4c are both destroyed.

(28) Thereafter, the laminated printed layer 4 is removed in the shape of the graphic 5b2 by being scanned with laser light as illustrated in FIG. 4C. In addition, at this time, an end face of a hole portion becomes vertical. Because incomplete light shielding area does not exist in a peripheral portion of the graphic 5b2 a contour of the graphic 5b2 is clear.

(29) In this process, the laser light passes through the resin sheet 3 and reaches the back surface printed layer 7. However, the printed layers 7a and 7b are not deteriorated by the laser light, and therefore the printed layers 7a and 7b remain as they are. As a result, the graphic 5b2 is a color or a pattern constructed by the printed layers 7a and 7b as seen from a top surface of the panel element 1. Note that the printed layers 7a and 7b are printed so as to be wider than the shape of the graphic 5b2 in consideration of a slight deviation of the position of a hole.

(30) The resin sheet 3 preferably has a thickness of 0.5 mm or less. At least the laminated printed layer 4 is much thinner (about 50 m even in a case of 10 layers) than the resin sheet 3. Therefore, the printed layers 7a and 7b are disposed on the back side of the resin sheet 3, but actually the back surface printed layer 7 does not appear to be so deep. That is, the back surface printed layer 7 can appear to be flat to some extent, and an aesthetic appearance can be maintained. In addition, by reducing the thickness of the resin sheet 3, it is able to obtain an effect of suppressing an influence on an adjacent graphic due to light guiding inside the sheet.

(31) Laser marking may be performed after the forming process of the printed resin sheet 3 or after attachment of the resin sheet 3 to the molded resin portion 2, that is, after injection. According to the latter method, distortion of a graphic is hardly generated, and the graphic can be deployed at a predetermined position of the panel element 1.

(32) As described above, the method for manufacturing the panel element 1 according to an aspect of the present invention is consisted of a process of printing the printed layer 4a formed of an ink that does not transmit light on the front side of the resin sheet 3 and a process of superimposing and printing the printed layers 4b and 4c on an upper surface of the printed layer 4a to form the laminated printed layer 4 and a process of removing a part of the laminated printed layer 4 by irradiating with laser light to form a hole portion having a vertical end face in the laminated printed layer 4.

(33) The printed layers 4a, 4b, and 4c of the panel element 1 are printed by screen printing with high detail. Therefore, it is possible to apply a beautiful decoration comparable to conventional gravure printing, such as a woodgrain tone, to the panel element 1. In addition, when a graphic (punched character or punched pattern) is formed by irradiating the laminated printed layer 4 with laser light from a front side thereof, an end face of a hole portion is formed vertically. As a result, it is possible to obtain a panel element without incomplete light shielding area at a peripheral portion of a hole portion formed and having a graphic with a clear contour.

(34) The above description is a part of the embodiment of the present invention, and various other embodiments are contemplated. The laminated printed layer 4 on the front side of the resin sheet 3 and the back surface printed layer 7 on the back side thereof each may include any number of layers.

(35) For example, in order to improve scratch resistance of the printed surface of the panel element 1 after laser marking, a surface of the panel element 1 may be coated with a light-transmissive protective film of a light-curable coating material or a thermosetting coating material. Formation of such a scratch-resistant layer is essential in a case where the panel element 1 is used as a component for a vehicle.