JP2017102511A - Method for manufacturing touch panel having curved surface shape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a touch panel having a curved surface shape which is formed by vacuum molding a sensor molding having a transparent electrode printed thereon and a protective molding covering the surface side thereof into a curved shape using the same die.SOLUTION: A method for manufacturing a touch panel having a curved surface shape includes: defining a thickness of a transparent sensor sheet formed into a sensor molding having a curved surface by vacuum molding as t, a radius of curvature of a convex surface of a die used in vacuum molding as r, a mold shrinkage rate of a first transparent synthetic resin, which constitutes the sensor molding, as α1 and a mold shrinkage ratio of a second transparent synthetic resin, which constitutes a protective molding covering the surface side along the curved surface, as α2; selecting the transparent synthetic resin from two or more transparent synthetic resins satisfying expression (1): (r+t) α1≥t+r α2; and vacuum molding the sensor molding and the protective molding using a common die of which the radius of curvature of the convex surface is r, in a first step and a second step.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method of manufacturing a curved touch panel having a three-dimensional curved input operation surface, and more specifically, a sensor molded body in which detection electrodes are wired and a protective molded body covering the surface are formed by vacuum molding. The present invention relates to a method of manufacturing a curved touch panel to be laminated.

  The capacitive touch panel that detects the input operation position from the change in capacitance of the detection electrode due to the approach of the input operation body has detection electrodes formed on the front and back surfaces to detect the two-dimensional input operation position. Insulating sensor sheet and an insulating protective sheet laminated on the sensor sheet to protect the detection electrode on the surface side. Input operation to the input operation surface using the protective sheet surface as the input operation surface. The position is detected. Generally, a display device such as a liquid crystal display device is placed inside (back side) of this capacitive touch panel, and the operator inputs the corresponding position while viewing the display of the display device icons and the like that appear on the input operation surface. Manipulate. Therefore, the sensor sheet and the protective sheet are formed of a transparent body so that the display on the display device can be visually observed.

  Capacitive touch panels are widely used as input devices for mobile phones, home appliances, car navigation systems for automobiles, etc., because they can detect the input operation position with high accuracy without touching the detection electrodes while looking at the display on the display device. There is also known a capacitive touch panel 100 in which the input operation surface is not limited to a flat surface but has a curved shape because of its various uses (Patent Document 1).

  As shown in FIG. 5, this capacitive touch panel 100 is an insulating material in which an X electrode layer 102 and a Y electrode layer 103 for detecting a two-dimensional input operation position are printed separately on the front surface and the back surface. The sensor sheet 101, the buffer layers 104 and 105 formed on the front and back surfaces of the sensor sheet 101, and the protective sheet 106 that further covers the buffer layer 104 on the front side are laminated to input the surface of the protective sheet 106. The entire laminated surface is curved leaving a peripheral flat surface so that the operation surface T is outwardly curved.

  Each of the above-described parts constituting the capacitive touch panel 100 is formed of a transparent material so that the display of the liquid crystal display device disposed below from the upper side in the figure can be visually observed. Among them, the sensor sheet 101 and the protective sheet 106 are In order to perform the curve forming process described later, it is formed of a transparent synthetic resin which is a thermoplastic resin.

  In this method of manufacturing the capacitive touch panel 100, first, an X electrode layer 102 and a Y electrode layer 103 made of transparent conductive ink are pattern-printed on the front and back surfaces of the sensor sheet 101, and the buffer layer is formed on each of them. 104 and 105 are screen-printed. Subsequently, the four corners of the sensor sheet 101 on which the electrode layers 102 and 103 and the buffer layers 104 and 105 are printed on the front and back surfaces are clamped horizontally on a vacuum forming mold to form a curved crown.

  In vacuum molding, the sensor sheet 101 heated at a molding temperature exceeding the thermal deformation temperature of the sensor sheet 101 is pressed along the molding surface of the mold heated to the same molding temperature, and the gap between the sensor sheet 101 and the molding surface is vacuumed. Suction to adhere to the molding surface. During the molding, the sensor sheet 101 is heated and softened at a molding temperature exceeding the thermal deformation temperature, and thus is molded into a shape along the spherical crown of the molding surface while being stretched. Thereafter, the sensor tote 101 is released from the mold and then cooled to room temperature to obtain a sensor sheet 101 in which the whole including the electrode layers 102 and 103 and the buffer layers 104 and 105 are curved in a spherical crown.

  When the sensor sheet 101 is stretched into a shape along the spherical crown of the molding surface of the mold, the electrode layers 102 and 103 printed and formed on the front and back surfaces of the sensor sheet 101 are also stretched at the same time. There is a possibility that a part of the electrode layers 102 and 103 may be disconnected around. In the capacitive touch panel 100 of Patent Document 1, a large number of conductive particles 107 are dispersed in the buffer layers 104 and 105 that are bent at the same time, particularly around the stretched portions, and the disconnected portion is interposed via the conductive particles 107. In general, however, the disconnection of the electrode layers 102 and 103 exposed on the front and back surfaces of the sensor sheet 101 after forming the true cavity is repaired by a method such as partial plating. Therefore, the protective sheet 106 that covers at least the X electrode layer 102 cannot be curved by true cavity molding together with the sensor sheet 101, and must be laminated on the sensor sheet 101 after being curved separately.

  In the capacitive touch panel 100, the sensor sheet 101 having a curved shape is placed in a mold for injection-molding the protective sheet 106, and a transparent synthetic resin serving as the protective sheet 106 that is heated and melted between the buffer layer 104 and the mold. And is integrally formed on the surface of the buffer layer 104 by injection molding. Thereby, the capacitive touch panel 100 in which the input operation surface T on the surface of the protective sheet 106 becomes a curved surface of the spherical crown toward the outside is manufactured.

  The vacuum molding described above has few restrictions on the materials that can be selected, and can produce molded products with a three-dimensional curved surface shape from raw materials with high yield. The front and back surfaces are not exposed in the injection mold. It is suitable for manufacturing touch panels having an arbitrary three-dimensional curved shape. Therefore, in general, the protective sheet 106 is also formed by vacuum forming using another mold having a curvature radius of the molding surface longer than that of the mold for forming the sensor sheet 101. In this case, each of the protective sheets 106 is curved by vacuum forming. The two types of sensor sheets 101 and protective sheets 106 having different outer diameters are assembled together.

JP 2014-96061 A

  In the method of manufacturing the capacitive touch panel 100 described in Patent Document 1, a sensor sheet 101 molded into a three-dimensional curved surface is placed in an injection mold, and a molding resin that melts between the surface and the mold is used. Since filling is performed, if the electrode layer 102 or the decorative layer is formed on the surface of the sensor sheet 101, the sensor sheet 101 may be thermally deformed or damaged due to fluid pressure.

  In addition, vacuum molding and injection molding molding processes that are completely different from each other are required, which increases the size of the manufacturing equipment and complicates the manufacturing process.

  On the other hand, even when the sensor sheet 101 and the protection sheet 106 are formed into a curved shape in the same vacuum forming process, the curvature radius of the protection sheet 106 is larger than that of the sensor sheet 101, and therefore the curvature radius of the forming surface is different. Two types of molds need to be used.

  Also, in vacuum forming, there is uneven heating temperature in the part to be molded depending on the heating position of the sheet or mold, and the heat-softened sheet cannot be uniformly sucked into the mold surface of the mold, so it can be curved with high accuracy as designed. When a molded product having a shape cannot be formed, and the sensor sheet 101 and the protective sheet 106 are separately molded using two types of molds, the gap between the two becomes uneven. As a result, since the distance from the input operation surface T on the surface of the protective sheet 106 to the electrode layers 102 and 103 differs depending on the location, the detection accuracy of the input operation position on the input operation surface T deteriorates. Moire fringes (light interference fringes) are generated due to unevenness in the gap between the protective sheets 106, which may impair the aesthetics.

  The present invention has been made in consideration of such conventional problems. A sensor molded body having a transparent electrode printed on a surface thereof and a protective molded body covering the surface side are formed by using the same mold. It aims at providing the manufacturing method of the curved-surface-shaped touchscreen which uses and vacuum-forms to a curved shape.

In order to achieve the above-mentioned object, the method for manufacturing a curved touch panel according to claim 1 is characterized in that a transparent sensor sheet formed of a first transparent synthetic resin having a transparent electrode printed on a surface thereof is used for the first transparent synthetic resin. The first step is to form a sensor molded body having a three-dimensional curved surface by heating to a molding temperature equal to or higher than the thermal deformation temperature, vacuum-forming the heat-softened sheet using a mold having a convex curved surface, and then cooling to room temperature after mold release. Then, the transparent protective sheet formed from the second transparent synthetic resin is heated to a molding temperature equal to or higher than the thermal deformation temperature of the second transparent synthetic resin, and the heat-softened sheet is vacuum-molded using a mold having a convex curved surface. A curved surface comprising a second step of cooling to room temperature after mold release to form a protective molded body having a three-dimensional curved surface, and a third step of laminating the protective molded body on the surface side of the sensor molded body and fixing them together Manufacturing of shape touch panel In law,
The thickness of the transparent sensor sheet is t, the radius of curvature of the convex curved surface of the mold used for vacuum molding is r, the molding shrinkage of the first transparent synthetic resin by vacuum molding is α1, and the molding shrinkage of the second transparent synthetic resin by vacuum molding. Let α2 be the rate
A first transparent synthetic resin and a second transparent synthetic resin,
(R + t) · α1 ≧ t + r · α2 (2) selected from two or more transparent synthetic resins satisfying the formula (1),
In the first step and the second step, the sensor molded body and the protective molded body are vacuum-molded using a mold having a common curved surface with a radius of curvature r.

  In the first step, the transparent sensor sheet is heated to a molding temperature equal to or higher than the thermal deformation temperature of the first transparent synthetic resin, so that it is softened by heating and pulled by being sucked into a convex curved surface having a radius of curvature r of the mold. The surface side is curved with a radius of curvature r + t. Since the sensor molded body cooled to room temperature after mold release contracts at a molding contraction rate α1, the surface side is curved with a radius of curvature (r + t) − (r + t) · α1.

  In the second step, the transparent protective sheet is heated to a molding temperature equal to or higher than the thermal deformation temperature of the second transparent synthetic resin, so that it is softened by heating and pulled by being sucked into a convex curved surface having a radius of curvature r of the mold. The back surface side along the mold is curved with a radius of curvature r. The protective molded body cooled to room temperature after mold release contracts at a molding shrinkage rate α2, and the back surface side has a radius of curvature (r + t) − (r + t) · long curvature radius r− greater than or equal to α1 on the surface side of the sensor molded body. Since it bends at r · α2, in the third step, a protective molded body can be laminated on the surface side of the sensor molded body to fix them together.

In the method of manufacturing the curved touch panel according to claim 2, the third step is a step of fixing the mutual with a transparent adhesive interposed in a minute gap δ between the sensor molded body and the protective molded body, 1 transparent synthetic resin and 2nd transparent synthetic resin,
(R + t) · α1 = t + δ + r · α2 (2) More than one transparent synthetic resin satisfying the formula (2) is selected.
It is characterized by that.

  The surface side of the sensor molded body is curved with a radius of curvature (r + t)-(r + t) · α1, and the back side of the protective molded body is curved with a radius of curvature rr · α2. A minute gap δ with a transparent adhesive interposed therebetween is formed.

  In the method of manufacturing a curved touch panel according to claim 3, the three-dimensional curved surface of the sensor molded body and the protective molded body is a spherical crown, and the convex curved surface of the mold used in common in the first step and the second step is , A spherical crown with a radius r.

  A touch panel with a spherical crown is manufactured, and the input operation surface T on the surface thereof is a spherical surface.

  The method for manufacturing a curved touch panel according to claim 4 is characterized in that the first transparent synthetic resin is polycarbonate and the second transparent synthetic resin is polymethyl methacrylate resin.

  Both the polycarbonate and the polymethyl methacrylate resin are transparent thermoplastic resins, and the molding shrinkage rate α1 due to vacuum molding of the polycarbonate is larger than the molding shrinkage rate α2 due to vacuum molding of the polymethyl methacrylate resin. The curvature radius of the polycarbonate sensor molded body that is curved by the mold is shorter than that of the polymethyl methacrylate resin protective molded body, and the protective molded body can be laminated on the surface side of the sensor molded body.

  According to the first aspect of the present invention, by using the difference in molding shrinkage due to vacuum molding of two kinds of transparent synthetic resins, a sensor mold having a curved radius of curvature and a protective mold having a common mold are used. Can be molded.

  In addition, since the sensor molded body and the protective molded body are vacuum-formed under the same conditions using the same mold, the individual molding accuracy is low, but the relative shape including the gap δ between them is molded with high accuracy. The input operation position on the input operation surface T that is a dimensional curved surface can be detected with high accuracy.

  According to the invention of claim 2, since the thickness of the transparent adhesive for fixing the sensor molded body and the protective molded body can be made constant by the minute gap δ, the input operation surface T having a three-dimensional curved surface and the sensor molded body. The distance between the transparent electrode and the transparent electrode formed on the input operation surface T can be detected with high accuracy.

  According to the third aspect of the present invention, the input operation can be performed as if the track ball that rolls the sphere accommodated in the casing is operated.

  Since a large touch panel having a spherical crown diameter of several tens of centimeters can be manufactured by vacuum forming, a touch panel simulating the globe can be obtained by projecting a map of the earth or the like onto the input operation surface T from below.

According to the invention of claim 4, the sensor molded body made of polycarbonate and the protective molded body made of polymethyl methacrylate resin covering the surface side of the sensor molded body with a minute gap δ,
(R + t) .multidot..alpha.1 = t + .delta. + R.multidot..alpha.2 (2) The curve can be formed using a common mold having a radius of curvature r satisfying the equation (2).

It is a perspective view which shows the use condition of the curved-surface-shaped touch panel 1 manufactured with the manufacturing method of the curved-surface-shaped touch panel which concerns on one embodiment of this invention. 1 is a longitudinal sectional view of a curved touch panel 1. It is a principal part expanded sectional view of FIG. The sheets 40 and 50 and the mold 20 in the process of vacuum forming are shown, (a) shows a state where the sheets 40 and 50 and the mold 20 are heated, and (b) shows a molding surface 20a of the mold 20 and (C) is a longitudinal sectional view showing a state in which the sheets 40 and 50 are vacuum-sucked, and (c) is a state in which the sheets 40 and 50 are in close contact with the molding surface 20a of the mold 20. It is a longitudinal cross-sectional view which shows the conventional curved-surface-shaped touch panel 100. FIG.

  A curved touch panel 1 manufactured by a method for manufacturing a curved touch panel according to an embodiment of the present invention is a capacitance type that is curved and formed along a hemisphere having a diameter of about 300 mm as shown in FIGS. Since it is a touch panel (hereinafter simply referred to as a touch panel) 1 and is entirely formed of a transparent body, for example, as shown in FIG. 1, it is disposed on the housing 2 and installed in the housing 2. A map of the earth is projected from the projector 3 toward the back surface of the touch panel 1, and is imitated as a globe in which the lower hemisphere portion is accommodated in the housing 2.

  The surface that is a hemispherical surface of the touch panel 1 is an input operation surface T that detects an input operation position of a finger that is an input operation body by a capacitance method, and the input operation position detected by the touch panel 1 and its movement locus. Thus, the image projected by the projector 3 is changed. For example, when the finger is traced to the left side along the input operation surface T, the map pattern projected onto the touch panel 1 by the projector 3 moves in the same direction, and the operator feels as if he has rotated the globe to the left side. Is obtained.

  In order to detect the input operation position on the input operation surface T, a plurality of X electrode lines and a plurality of Y electrode lines (not shown) made of transparent conductive ink are formed on the front and back surfaces of the sensor molded body 4 curved in a hemisphere. Z) is printed. The plurality of X electrode lines are wired at the same pitch on the surface of the sensor molded body 4, and the plurality of Y electrode lines are arranged at the same pitch on the back surface of the sensor molded body 4 in a direction orthogonal to the wiring direction of the X electrode lines. Wired.

  An input operation position detection circuit (not shown) of the touch panel 1 sequentially outputs a drive control signal to a plurality of X electrode lines and monitors the level of the drive control signal appearing on the Y electrode line that intersects the X electrode line that has output the drive control signal. When the input operation body approaches, the input operation position is determined from the Y electrode line where the capacitance changes and the level of the drive control signal changes, and the wiring position of the X electrode line that outputs the drive control signal at that time. To detect.

  Further, the surface side of the sensor molded body 4 to which the X electrode lines are wired is hemispherical so that a foreign object or an input operation body does not directly contact and break the plurality of X electrode lines formed on the surface of the sensor molded body 4. It is covered with a protective molded body 5 that is curved.

  Hereinafter, about the manufacturing method of the touch panel 1 comprised in this way, the 1st process which manufactures the sensor molding 4, the 2nd process which manufactures the protection molding 5, and the protection molding 5 on the surface side of the sensor molding 4 The description will be divided into the third step of fixing in a stacked state.

(First step of manufacturing the sensor molded body 4)
The sensor molded body 4 is formed into a hemisphere by vacuum forming a sensor sheet 40 made of a transparent thermoplastic resin having a thickness t of 0.3 mm using a mold 20 having a molding surface 20a shown in FIG. Curved formation. The radius r of the molding surface 20a that is the hemispherical surface is 150 mm in order to curve the sensor molded body 4 into a hemispherical surface having a diameter of about 300 mm.

The thermoplastic resin constituting the sensor sheet 40 is a transparent insulator, the thermoplastic resin has a thermal deformation temperature equal to or lower than the molding temperature in vacuum molding, and a vacuum when cooled from the molding temperature to room temperature. The molding shrinkage rate α1 due to molding is larger than the molding shrinkage rate α2 due to vacuum molding when the thermoplastic resin forming the protective molded body 5 described later is cooled from the molding temperature to room temperature,
(R + t) .multidot..alpha.1.gtoreq.t + r.multidot..alpha.2 (1) is a condition for selecting the thermoplastic resin constituting the sensor sheet 40. Here, the thermoplastic resin constituting the sensor sheet 40. Is a polycarbonate having a thermal deformation temperature of about 135 ° C. and a molding shrinkage ratio α1 of 6/1000.

  Before vacuum forming the sensor sheet 40, a plurality of X electrode lines and a plurality of Y electrode lines are printed on the front and back surfaces. Since the sensor sheet 40 is stretched so as to be away from the inner top surface that is curved into a hemispherical surface during vacuum forming, the plurality of X electrode lines and the plurality of Y electrode lines to be printed on the sensor sheet 40 are In order to be wired at equal pitches on the front and back surfaces of the stretched sensor molded body 4, the sensor molded body 4 is wired at an interval in advance that takes into account the expansion rate by vacuum forming.

  As shown in FIG. 4A, the vacuum forming of the sensor sheet 40 is performed by first clamping the four corners of the sensor sheet 40 with the X and Y electrode lines printed and wired on the front and back surfaces. The sensor sheet 40 and the mold 20 are heated to 170 ° C., which is disposed horizontally above the molding surface 20 a that is a surface and is higher than the heat deformation temperature of the polycarbonate constituting the sensor sheet 40.

  Subsequently, as shown in FIG. 4B, in the overheated state, the mold 20 is raised and the sensor sheet 40 is lowered while pulling the four corners so that the sensor sheet 40 covers the entire molding surface 20a. Press. At this time, since the sensor sheet 40 exceeds the heat deformation temperature, the sensor sheet 40 is heated and softened, and is stretched along the molding surface 20a with strain exceeding the elastic limit. Thereafter, the gap between the sensor sheet 40 and the molding surface 20a is vacuum-sucked from the minute holes of the mold 20, and as shown in FIG. 4 (c), the sensor sheet 40 is stretched and brought into close contact with the hemispherical molding surface 20. This vacuum suction process is a kind of drawing process, and the peripheral edge of the sensor sheet 40 is particularly greatly extended along the hemispherical surface.

  Thereafter, the sensor sheet 40 is detached from the mold 20 and left until it is cooled to room temperature (for example, 20 ° C.) to obtain the sensor molded body 4 that is a hemispherical molded product. While the sensor molded body 4 is cooled from a molding temperature of 170 ° C. to 20 ° C., which is normal temperature, the sensor molded body 4 contracts at a molding shrinkage ratio α1 of 6/1000 of the polycarbonate. As a result, the curvature radius 150.3 mm of the outer surface of the sensor sheet 40 stretched along the molding surface 20a is contracted with a molding shrinkage ratio α1 of 6/1000, and the curvature radius of the outer surface of the sensor molded body 4 is reduced. r1 is about 149.4 mm.

  Then, after repairing the disconnection by partial plating of the plurality of X electrode lines and the plurality of Y electrode lines printed and formed on the front and back surfaces of the sensor molded body 4, the tail portion drawn from each electrode line and the edge of the hemisphere The sensor molded body 4 is obtained by trimming the periphery of the ring piece portion 4a while leaving the ring piece portion 4a along the line.

(Second step of manufacturing the protective molded body 5)
The protective molded body 5 is curvedly formed into a hemisphere from the protective sheet 50 made of a transparent thermoplastic resin having a thickness t of 3 mm, using the same mold 20 used for vacuum molding of the sensor molded body 4. The protective molded body 5 covers the surface side of the sensor molded body 4 at equal intervals. The radius r of the molding surface 20a of the mold 20 that is a hemisphere is the molding surface 20a when the sensor molded body 4 is molded. It is the same 150mm.

The thermoplastic resin constituting the protective sheet 50 is a transparent insulator, the thermoplastic resin has a thermal deformation temperature equal to or lower than the molding temperature in vacuum molding, and a vacuum when cooled from the molding temperature to room temperature. The molding shrinkage rate α2 due to molding is smaller than the molding shrinkage rate α1 due to vacuum molding of the thermoplastic resin forming the sensor molded body 4,
(R + t) · α1 ≧ t + r · α2 (1) satisfying the relationship of the formula (1) is a selection condition of the thermoplastic resin constituting the protective sheet 50. Here, the thermoplastic resin constituting the protective sheet 50 Is a polymethyl methacrylate resin (hereinafter referred to as PMMA) having a thermal deformation temperature of about 90 ° C. to 105 ° C. and a molding shrinkage ratio α2 of 2/1000.

  Hereinafter, since the vacuum forming process of forming the protective molded body 5 from the protective sheet 50 is the same as the vacuum forming process of the sensor molded body 4 shown in FIG. 4, the sensor sheet 40 and the protective sheet 50 are added to the sheets in the figure. A description will be given with reference numerals 40 and 50 indicating any of the above. First, as shown in FIG. 4A, the four corners of the protective sheet 50 are clamped and horizontally disposed above the molding surface 20 a that is the hemispherical surface of the mold 20, and is the same as the molding temperature of the sensor sheet 40. The protective sheet 50 and the mold 20 are heated up to 170 ° C., which is higher than the thermal deformation temperature of PMMA constituting the protective sheet 50.

  Subsequently, as shown in FIG. 4B, in the overheated state, the mold 20 is raised and the protective sheet 50 is lowered while pulling the four corners so that the protective sheet 50 covers the entire molding surface 20a. Press. At this time, since the protective sheet 50 exceeds the heat deformation temperature, it is softened by heating, and is stretched along the molding surface 20a with strain exceeding the elastic limit. Thereafter, the gap between the protective sheet 50 and the molding surface 20a is vacuum-sucked from the minute holes of the mold 20, and as shown in FIG. 4 (c), the peripheral edge of the protective sheet 50 is greatly extended along the hemispherical surface to protect it. The sheet 50 is brought into close contact with the hemispherical molding surface 20.

  Thereafter, the protective sheet 50 is detached from the mold 20 and left to cool to room temperature (for example, 20 ° C.) to obtain the protective molded body 5 which is a hemispherical molded product. The protective molded body 5 shrinks at a molding shrinkage rate α2 of PMMA of 2/1000 while being cooled from a molding temperature of 170 ° C. to 20 ° C. of ordinary temperature. As a result, the curvature radius 150 mm of the inner surface of the protective sheet 50 stretched along the molding surface 20a is shrunk at a molding shrinkage ratio α2 of 2/1000, and the curvature radius r2 of the inner surface of the protection molded body 5 is 149.7 mm.

  Thereafter, the periphery of the ring piece portion 5a is trimmed while leaving the ring piece portion 5a along the edge of the semicircular sphere, and the protective molded body 5 is obtained.

(Third step of fixing in a state where the protective molded body 5 is laminated on the surface side of the sensor molded body 4)
As described above, the sensor molded body 4 and the protective molded body 5 are hemispherically curved, and the radius of curvature of the outer surface of the sensor molded body 4 is about 149.4 mm as described above. The radius of curvature is 149.7 mm, and while being vacuum-formed under the same conditions using the mold 20 having the same molding surface 20a, a hemispherical curve is formed with a gap δ of approximately 0.3 mm therebetween. . This is due to the difference between the molding shrinkage rate α1 of polycarbonate by vacuum molding and the molding shrinkage rate α2 of PMMA. Generally, a thermoplastic resin by vacuum molding has a distance between molecules before and after the thermal deformation temperature of the resin. The main factor is density change due to solidification and cooling from a softened state that is long and easily deformed to a solid with a short distance between molecules, but other factors such as release of tensile stress by vacuum suction, plastic change, and normal temperature from molding temperature. The molding shrinkage rate α that shrinks before and after vacuum molding due to various factors such as the difference in cooling temperature until is determined for each thermoplastic resin material. In the present invention, the sensor molded body 4 disposed inside is formed of a thermoplastic resin having a molding shrinkage rate α1 larger than that of the thermoplastic resin constituting the protective molded body 5 disposed outside the curved surface. By doing so, the curved touch panel 1 in which two or more types of molded bodies 4 and 5 are laminated using the same mold 20 can be formed.

  Therefore, as shown in FIG. 2, the ring piece portion 5a of the protective molded body 5 is concentrically overlapped on the ring piece portion 4a of the sensor molded body 4, and both are arranged around the same center O with a certain gap δ therebetween. The curved touch panel 1 in which the protective molded body 5 is laminated on the surface side of the hemispherical sensor molded body 4 is manufactured by laminating and fixing the ring pieces 4a and 5a using an adhesive or the like. In addition, since the gap δ between the sensor molded body 4 and the protective molded body 5 formed along the curved surface is formed at an equal interval, a transparent adhesive may be sealed between them to fix them together. Good.

In the above-described embodiment, the thermoplastic resin constituting the sensor molded body 4 and the protective molded body 5 is
(R + t) · α1 ≧ t + r · α2 (Selected from a thermoplastic resin having a molding shrinkage rate α that satisfies the formula (1).
When a gap δ between the sensor molded body 4 and the protective molded body 5 between which the adhesive is fixed is fixed,
(R + t) · α1 = t + δ + r · α2 (2) The thermoplastic resin constituting the sensor molded body 4 and the protective molded body 5 can be selected from thermoplastic resins having a molding shrinkage rate α that satisfies the formula (2).

  In the above-described embodiment, the sensor molded body 4 is manufactured before the protective molded body 5. However, even if the protective molded body 5 is manufactured first, the first and second steps are performed in the reverse order. Good.

  Furthermore, the curved surface touch panel 1 described above can be applied not only to a spherical crown such as a hemisphere, but also to a curved surface touch panel that is a part of a spherical surface. In addition, the present invention can be applied to a curved touch panel that detects an input operation position by a resistive film method, an electromagnetic induction method, an optical method, an ultrasonic method, or the like.

  It is suitable for a method of manufacturing a curved touch panel in which an input operation surface is curved by vacuum forming.

DESCRIPTION OF SYMBOLS 1 Curved surface shape touch panel 4 Sensor molded object 5 Protection molded object 20 Mold 20a Molding surface 40 Sensor sheet 50 Protective sheet

Claims (4)

A transparent sensor sheet formed of a first transparent synthetic resin having a transparent electrode printed on its surface is heated to a molding temperature equal to or higher than the thermal deformation temperature of the first transparent synthetic resin, and the heat-softened sheet has a convex curved surface. A first step of forming a sensor molded body having a three-dimensional curved surface by cooling to room temperature after mold release using
The transparent protective sheet formed from the second transparent synthetic resin is heated to a molding temperature equal to or higher than the thermal deformation temperature of the second transparent synthetic resin, and the heat-softened sheet is vacuum-molded using a mold having a convex curved surface and separated. A second step of cooling to room temperature after molding to form a protective molded body having a three-dimensional curved surface;
In the method for manufacturing a curved touch panel, comprising a third step of laminating a protective molded body on the surface side of the sensor molded body and fixing each other,
In the first step and the second step, the sensor molded body and the protective molded body are vacuum-formed using a mold having a common curvature radius r of the convex curved surface,
The thickness of the transparent sensor sheet is t, the radius of curvature of the convex curved surface of the mold used for vacuum molding is r, the molding shrinkage of the first transparent synthetic resin by vacuum molding is α1, and the molding of the second transparent synthetic resin by vacuum molding. The shrinkage rate is α2,
A first transparent synthetic resin and a second transparent synthetic resin,
(R + t) · α1 ≧ t + r · α2 (2) selected from two or more transparent synthetic resins satisfying the formula (1),
A method of manufacturing a curved touch panel, wherein a sensor molded body and a protective molded body are vacuum-formed using a mold having a curvature radius r common to the convex curved surface in the first step and the second step. The third step is a step of fixing each other with a transparent adhesive interposed in a minute gap δ between the sensor molded body and the protective molded body,
A first transparent synthetic resin and a second transparent synthetic resin,
2. The method for manufacturing a curved touch panel according to claim 1, wherein the method is selected from two or more transparent synthetic resins satisfying the formula (r + t) · α1 = t + δ + r · α2 (2). The three-dimensional curved surface of the sensor molded body and the protective molded body is a spherical crown, and the convex curved surface of the mold used in common in the first step and the second step is a spherical crown having a radius r. The manufacturing method of the curved-surface-shaped touchscreen of any one of Claim 1 or Claim 2. 4. The curved touch panel manufacturing method according to claim 1, wherein the first transparent synthetic resin is polycarbonate and the second transparent synthetic resin is a polymethyl methacrylate resin. 5. Method.

Images