JP2005289015A - Metal masking plate for screen printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal masking plate for screen printing which hardly generates an angular protrusion even when the periphery of an electronic component (120) is sealed with resin by screen printing. <P>SOLUTION: The metal masking plate has a through hole (2) which forms a resin inflow space (4) between the periphery of the electronic component (120) and the metal masking plate, the through hole (2) being constituted of a lower small-diameter hole (2B) and an upper large-diameter hole (2A) communicating with a spot above the lower small-diameter hole (2B), and a stepped part (6) is formed inside the through hole (2). When the metal masking plate (1) for screen plating is removed, only the inside surface of the lower small-diameter hole (2B) comes into contact with a sealing resin (3) sticking to the electronic component (120). Therefore, the shear area is small and the sealing resin (3) is cut apart before the angular protrusion could be generated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a metal mask plate for screen printing that is used when the periphery of an electronic component mounted on a substrate is resin-sealed by screen printing.

  Electronic components mounted on a printed circuit board or other substrate have electrodes exposed on the surface, which are subject to aging, such as oxidation and sulfidation, and may short-circuit between electrodes and other conductors. Therefore, the whole is generally sealed with an insulating resin.

  Conventionally, a screen printing method using a metal mask plate is known as a resin sealing method for sealing an electronic component with a resin (see Patent Document 1).

Japanese Patent No. 3128612 (2nd page, FIG. 9)

  In this resin sealing method using screen printing, an insulating sealing resin is applied to the periphery of an electronic component in the form of ink for screen printing. As shown in FIG. A metal mask plate 103 in which a through hole 105 slightly larger than the outline of 120 is formed covers the substrate 102 on which the electronic component 120 is mounted, and the squeegee 104 is slid along the surface of the metal mask plate 103 to pass through the substrate. The sealing resin 106 is filled in the gap between the hole 105 and the electronic component 120.

  Thereafter, the metal mask plate 103 is removed, and the sealing resin 106 attached to the periphery of the electronic component 120 is heat-cured and fixed around the electronic component 120 for sealing.

  According to the screen printing method, the metal mask plate 103 can be reused, and all the electronic components fixed on the substrate 102 can be simultaneously sealed with resin, so that it is suitable for mass production and the process is simple, and therefore suitable for automation.

  In this conventional resin sealing method, a material having fluidity and viscosity is used for the sealing resin 106 in order to fill the through hole 105 using the squeegee 104. Therefore, when the metal mask plate 103 is removed from the periphery of the electronic component 120, a part of the sealing resin 106 adhering to the periphery of the edge portion of the electronic component 103 is removed from the inner surface of the through hole 105 as shown in FIG. In the state shown in FIG. 12 in which the metal mask plate 103 is completely separated and heat-cured by being attached to and pulled on, a rectangular protrusion 107 is formed due to the sealing resin 106 remaining on the edge portion of the electronic component 103.

  As a result, not only the appearance is inferior, but also the angular protrusion 107 comes into contact with other parts, which causes an obstacle to high-density mounting, and causes an insulation failure or a contact failure. .

  In particular, in a touch panel input device in which a display panel such as a liquid crystal display element is laminated on the back side of a transparent touch panel, when a piezoelectric substrate fixed on the back side is used as a vibration source of the touch panel, When 107 is formed on the piezoelectric substrate, the display plate cannot be disposed in contact with the touch panel and close to the touch panel, and the display plate is difficult to see.

  Further, when the square projection 107 is in contact with the display board, the vibration of the piezoelectric substrate is restrained, and there is a problem that the touch panel cannot be vibrated with sufficient amplitude.

  The present invention has been made in consideration of the above-described conventional problems. For screen printing, even when the periphery of an electronic component is resin-sealed by screen printing, square projections are unlikely to occur. The object is to provide a metal mask version.

  In order to achieve the above-described object, the metal mask plate for screen printing according to claim 1 is provided with a through-hole for accommodating the entire electronic component mounted on the substrate, and covers the substrate in a state where the electronic component is covered. A metal mask plate for screen printing in which a sealing resin is filled into a resin inflow space formed between a periphery and a through hole, then removed from the substrate, and the sealing resin is attached to the periphery of the electronic component, An interval corresponding to the thickness of the sealing resin to be attached to the metal mask plate for screen printing thicker than the height of the electronic component mounted on the substrate, outside the contour projected on the substrate of the electronic component. A lower small diameter hole in the through hole is formed, and a lower small diameter hole communicating with the lower small diameter hole above the lower contour and the upper large diameter hole including the contour of the lower small diameter hole is formed. A step is formed at the boundary between the hole and the upper large-diameter hole. It is characterized in.

  Since a resin inflow space having an interval corresponding to the thickness of the sealing resin is formed between the side surface of the electronic component mounted on the substrate and the lower small diameter hole of the through hole, the metal mask plate for screen printing is used as the substrate. If the resin is removed in the vertical direction, a sealing resin having a predetermined thickness adheres to the side surface of the electronic component.

  The sealing resin adhering to the upper surface edge of the electronic component is partially pulled by the viscosity of the sealing resin adhering to the stepped portion in the through hole when removing the screen printing metal mask plate in the vertical direction. And adheres to the through hole side of the screen printing metal mask plate.

  In addition, the sealing resin adhering to the upper edge of the electronic component is cut off from the metal mask plate for screen printing with a lower small-diameter hole with a small area along the shearing direction, so it contacts the entire inner surface of the through-hole. Then, it is cut immediately compared to the case where it is pulled up largely from the edge portion.

  The metal mask plate for screen printing according to claim 2, wherein the metal mask plate for screen printing is formed above the lower layer metal mask plate and the lower layer metal mask plate in which a lower small-diameter hole is formed corresponding to the mounting part of the electronic component. And an upper metal mask plate having an upper large-diameter hole that is laminated and communicated with the lower small-diameter hole.

  The lower small-diameter hole and the upper large-diameter hole can be formed by applying an etching process to the lower metal mask plate and the upper metal mask plate, respectively. It can be easily formed with high accuracy corresponding to the mounting position of the electronic component.

  According to a third aspect of the present invention, there is provided a metal mask plate for screen printing, wherein the electronic component is a piezoelectric substrate that is fixed to the touch panel and vibrates when a pressing operation on the touch panel is detected.

  Since an angular protrusion due to the sealing resin is unlikely to occur at the edge portion of the electronic component, a display board for displaying an index of an input operation to the touch panel can be disposed in close contact with the upper surface side of the electronic component.

  According to the first aspect of the present invention, the sealing resin adhering to the edge portion of the electronic component partially adheres to the screen printing metal mask plate side when removing the screen printing metal mask plate, Since it is cut before it is pulled up, it is hard to remain as a horn-shaped projection after being cured.

  Therefore, the appearance of the electronic component after sealing is not impaired, and it does not contact other components and cause breakdown voltage failure or connection failure.

  According to the invention of claim 2, the through-hole having the step portion can be easily and accurately formed in the metal mask plate for screen printing.

  According to the invention of claim 3, the display plate can be further arranged close to the touch panel side to which the piezoelectric substrate is fixed, and the display on the display plate is easy to see. In addition, the angular protrusions on the sealing resin that seals the piezoelectric substrate do not touch other components or the substrate disposed in the vicinity of the touch panel, and the vibration of the piezoelectric substrate is not restricted.

  Hereinafter, a screen printing metal mask plate (hereinafter referred to as a metal mask plate 1) according to an embodiment of the present invention will be described with reference to FIGS. The metal mask plate 1 according to the present embodiment is used when a piezoelectric substrate 120 provided as a vibration component in the touch panel input device 100 shown in FIGS. 3 and 4 is resin-sealed. The apparatus 100 and the piezoelectric substrate 120 as the vibration source will be described with reference to FIGS. 3 is an exploded perspective view of the touch panel input device 100, and FIG. 4 is a rear view thereof.

  The touch panel input device 100 is also called a digitizer, and an operation area 100A for detecting a pressed position is set in a touch panel configured by laminating an operation panel 101 and a support substrate 102 with a slight gap therebetween. The illustrated touch panel input device 100 detects a pressing position by a resistance pressure-sensitive method. For this purpose, conductor layers 101a and 102a made of a uniform resistance film are deposited on the opposing surfaces of the operation panel 101 and the support substrate 102. The pair of piezoelectric substrates 120 and 120 are fixed to the back side of the support substrate 102 around the operation area 100A.

  The operation panel 101, the support substrate 102, and the conductor layers 101a and 102a attached to the opposing surfaces of the operation panel 101 and the support layer 102 are displayed on the display screen of a display device (not shown) arranged below the operator through the operation area 100A. However, both are made of a transparent material so that a pressing operation is possible.

  The piezoelectric substrate 120 is formed in an elongated band shape, a pair of drive electrodes 120a and 120b is formed on both front and back surfaces, and the front side is the back side of the support substrate 102 that becomes a touch panel using an adhesive or the like. In order not to block the line of sight to the display device, it is fixed in a slight gap between the operation area 100A and the periphery of the support substrate 102.

  The pressing operation on the operation area 100A is detected by contact between the conductor layers 101a and 102a. When the pressing operation is detected, a driving voltage is applied to the pair of driving electrodes 120a and 120b, and the piezoelectric substrate 120 expands and contracts. The entire touch panel including the support substrate 102 to which is attached is vibrated, and the operator confirms that the pressing operation is accepted from the vibration.

  Since the drive electrodes 120a and 120b of the piezoelectric substrate 120 fixed to the back surface of the support substrate 102 are exposed on the front, back, and side surfaces, the insulation from other components and the aging of the drive electrodes 120a and 120b themselves are caused. In order to prevent deterioration, the entire periphery is sealed with an insulating sealing resin.

  In the following description, as shown in FIG. 1, the back side of the support substrate 102 faces upward and the back side is covered with the metal mask plate 1, so that the back direction of the touch panel input device 100 shown in FIG. That is, the back surface of the piezoelectric substrate 120 is described as the upper surface 120A.

  The metal mask plate 1 is a metal plate made of a metal material such as aluminum or stainless steel, and as shown in FIGS. 2A and 2B, the lower metal mask plate 1B formed in the same rectangular shape. And the upper metal mask plate 1A, and the thickness of the metal mask plate 1 formed by stacking the upper metal mask plate 1A above the lower metal mask plate 1B is the piezoelectric substrate 120 fixed on the support substrate 102. It is thicker than the height.

  In the lower metal mask plate 1B, a lower small-diameter hole 2B is formed in a cylindrical shape in the vertical direction at a portion corresponding to the piezoelectric substrate 120 fixed on the support substrate 102. The lower small-diameter hole 2 </ b> B is formed in a contour shape that surrounds the periphery of the piezoelectric substrate 120 fixed on the support substrate 102 with a gap d corresponding to the thickness of the sealing resin 3. That is, the outline projected on the support substrate 102 of the lower small-diameter hole 2B is outside the outline (indicated by the broken line in FIG. 2A) where the piezoelectric substrate 120 is projected on the support substrate 102. The distance d corresponding to the thickness of the sealing resin 3 to be attached to the side surface is separated.

  In addition, the upper metal mask plate 1A has an upper large-diameter hole 2A formed in a cylindrical shape in the vertical direction corresponding to a portion where the lower small-diameter hole 2B is formed. The upper large-diameter hole 2A is formed in a contour shape that further surrounds the periphery of the lower small-diameter hole 2B formed in the lower metal mask plate 1B at a predetermined interval. That is, as shown in FIG. 2B, the contour of the upper large-diameter hole 2A projected on the support substrate 102 is spaced apart from the contour of the lower small-diameter hole 2B (indicated by a broken line in the figure). Thus, when the upper metal mask plate 1A is laminated on the lower metal mask plate 1B, a stepped step portion 6 is formed around the lower small-diameter hole 2B (see FIG. 1).

  The upper large-diameter hole 2A and the lower small-diameter hole 2B are formed, for example, on each of the two metal mask plates 1A and 1B by performing an etching process, and then the two tall mask plates 1A and 1B are overlapped. Are bonded and integrated by welding, bonding, etc. to form a metal mask plate 1. Thereby, the through hole 2 in which the lower small diameter hole 2 </ b> B and the upper large diameter hole 2 </ b> A communicate with each other in the vertical direction is formed in the metal mask plate 1 corresponding to the fixing portion of the piezoelectric substrate 120. When the support substrate 102 is covered with the metal mask plate 1 formed in this way, the entire piezoelectric substrate 120 is accommodated in the through hole 2, and a sealing resin is interposed between the inner surface of the through hole 2 and the piezoelectric substrate 120. 3 is formed (see FIGS. 5A and 5B).

  The interval between the resin inflow space 4, particularly the interval between the piezoelectric substrate 120 and the lower small-diameter hole 2 </ b> B, is such that the sealing resin 3 attached to the side surface of the piezoelectric substrate 120 does not protrude toward the operation area 100 </ b> A. The gap d is equal to or less than the gap d with respect to the substrate 120, which is 0.5 mm, which is equal to the distance d. The height of the through hole 2 is 1 mm, which is higher than the height of the piezoelectric substrate 120, assuming that the height of the piezoelectric substrate 120 is 0.7 mm.

  As the sealing resin 3 filled in the resin inflow space 4, a synthetic resin having at least insulating properties, thixotropic properties, and thermosetting properties is used. Here, an epoxy resin having these characteristics is used. The insulating property covers the entire surface of the piezoelectric substrate 120 where the pair of drive electrodes 120a and 120b are exposed, so that these electrodes are not short-circuited. Therefore, the thermosetting property is heated after filling and around the piezoelectric substrate 120. In order to be cured, each is required as a characteristic of the sealing resin 3. The thixotropy is also called thixotropy or thixotropy, which means that the viscosity decreases during flow and returns to the original high viscosity state when left standing. It is easy to fill, and after filling, it is required to maintain its shape until the heat curing step.

  In addition, it is preferable that the sealing resin 3 has a low shrinkage rate upon thermosetting, a certain elasticity after thermosetting, that is, a value having a small elastic modulus, and thermosetting at a low temperature. A low shrinkage rate upon thermosetting is required because a wiring pattern (120c, 120d, 120e, 120f in FIG. 4) in which the sealing resin 3 is drawn from the piezoelectric substrate 120 when the resin inflow space 4 is filled. This is because, if it adheres to the top and the shrinkage rate is high, these wiring patterns are pulled in at the time of thermosetting, resulting in pattern peeling or cutting. Further, a certain degree of elasticity is required in order not to constrain the distortion of the piezoelectric substrate 120 that becomes a vibration generation source after curing, and low-temperature curing is desired when a high temperature is required for curing. This is because 120 reaches the Curie point, polarization is disturbed, and no distortion occurs even when a drive voltage is applied.

  As shown in FIG. 1, the sealing resin 3 is placed in a state of flowing on one end of the metal mask plate 1 and is filled into the resin inflow space 4 of the through hole 2 by screen printing using a squeegee 5. . The squeegee 5 may be made of any material as long as the sealing resin 3 can be pushed out to the resin inflow space 4, but here, a rubber squeegee 5 is used.

  Hereinafter, each process of sealing the piezoelectric substrate 120 which is an electronic component with the sealing resin 3 using the metal mask plate 1 according to the present embodiment will be described with reference to FIGS. 1 and 5 to 9.

  First, a support substrate 102 is set on a slide table of a screen printing machine (not shown) with the fixing side of the piezoelectric substrate 120 as a front side, and as shown in FIG. 1 and FIG. A metal mask plate 1 having holes 2 is overlaid. In the stacked state, a resin inflow space 4 is formed between the piezoelectric substrate 120 and the through hole 2. The interval of the resin inflow space 4 between the periphery of the piezoelectric substrate 120 and the lower small-diameter hole 2B is as narrow as 0.5 mm, and the height of the piezoelectric substrate 120 is lower than the through-hole 2 but lower than the lower small-diameter hole 2B. It is high and slightly protrudes from the lower small-diameter hole 2B.

Thereafter, the squeegee 5 is slid along the surface of the metal mask plate 1 to fill the resin inflow space 4 with the sealing resin 3 placed on one side of the metal mask plate 1. In the filling process of the sealing resin 3, as shown in FIGS. 6A and 6B, the squeegee 5 is slid along the surface of the metal mask plate 1 and is placed on one side of the metal mask plate 1. The sealing resin 3 in the state is extruded along the surface of the metal mask plate 1 to uniformly fill the resin inflow space 4 including the surface side of the piezoelectric substrate 120 (see FIGS. 7A and 7B).

  Thereafter, as shown in FIGS. 8A and 8B, the metal mask plate 1 is pulled up in the vertical direction orthogonal to the support substrate 102, and as shown in FIGS. 9A and 9B, a viscous sealing resin is used. 3 is pulled up until it completely separates from the piezoelectric substrate 120 side. When the sealing resin 3 adhering to the periphery of the piezoelectric substrate 120 and the metal mask plate 1 are separated, a part of the sealing resin 3 filled around the edge portion of the upper surface 120A of the piezoelectric substrate 120 is shown in FIG. a) As shown in (b), the viscosity of the sealing resin 3 left on the step portion 6 is pulled up to the metal mask plate 1 side, and the amount of the sealing resin 3 adhering to the edge portion is reduced. In addition, the contact with the sealing resin 3 in the shearing direction (vertical direction) for cutting the sealing resin 3 is the inner surface of the lower small-diameter hole 2B having a smaller contact area than the entire through hole 2 of the metal mask plate 1. The adhesive strength of the sealing resin 3 to the metal mask plate 1 side is weak, and the sealing resin 3 can be separated by slightly lifting the metal mask plate 1.

  As a result, after the metal mask plate 1 is completely removed, no angular protrusions are generated around the edge portion of the upper surface 120A of the piezoelectric substrate 120. The sealing resin 3 adheres to the entire circumference with a uniform thickness of approximately 0.5 mm.

  The piezoelectric substrate 120 to which the sealing resin 3 is attached in this manner is moved into the high-temperature furnace at about 180 ° C. together with the support substrate 102, and the sealing resin 3 is thermally cured and fixed. Until the heat curing, the sealing resin 3 attached to the piezoelectric substrate 120 is in a stationary state, so that it returns to the original high viscosity state and maintains its shape. Therefore, the shape of the piezoelectric substrate 120 is maintained in a state where the entire circumference of the piezoelectric substrate 120 is completely covered while the thickness is 0.5 mm without being inclined downward along the side surface of the piezoelectric substrate 120.

  The piezoelectric substrate 120 sealed with the thermosetting sealing resin 3 does not come into contact with the outside air, prevents deterioration due to aging, and the electrodes are covered with the insulating sealing resin 3, so that they are short-circuited with others. There is no fear of doing. In addition, since a square-shaped protrusion does not appear on the edge portion of the upper surface 120A, a display panel such as a liquid crystal display panel can be arranged close to the back side of the support substrate 102, and display on the display panel through the touch panel can be performed. It will be easy for the operator to see.

  In the above-described embodiment, the piezoelectric substrate which is a vibration component is described as an electronic component to be resin-sealed. However, a metal mask plate used for resin-sealing various electronic components as long as it is mounted on the substrate. Applicable to.

  Further, the metal mask plate 1 is formed with a through hole having a step portion by overlapping the metal mask plates 1A and 1B made of two metal plates. However, other processing methods such as cutting may be applied to the single metal mask plate 1. It may be used to form a through hole having a stepped portion.

  The present invention is suitable for a metal mask plate in which a sealing resin is attached around an electronic component mounted on a printed wiring board or the like using a screen printing method.

FIG. 3 is a perspective view showing an arrangement relationship between the piezoelectric substrate 120 fixed to the support substrate 102 and the metal mask plate 1. (A) of the metal mask plate 1 is a plan view of the lower layer metal mask plate 1B, and (b) is a plan view of the upper layer metal mask plate 1A. 2 is an exploded perspective view of a touch panel input device 100. FIG. It is a rear view of the support substrate 102 to which the piezoelectric substrate 120 adheres. The state before starting the filling process which fills the resin inflow space 4 with the sealing resin 3 is shown, (a) is a longitudinal sectional view cut along the short direction of the through-hole 3, and (b) is a through-passage. FIG. 4 is a partially omitted longitudinal sectional view cut along the longitudinal direction of a hole 3. The filling process of filling the sealing resin 3 into the resin inflow space 4 is shown, (a) is a longitudinal sectional view as seen from the rear in the sliding direction of the squeegee 5, cut along the short direction of the through hole 3. ) Is a partially omitted longitudinal sectional view cut along the longitudinal direction of the through-hole 3. The filling state of the sealing resin 3 after the filling process is shown, (a) is a longitudinal sectional view cut along the short direction of the through hole 3, and (b) is along the longitudinal direction of the through hole 3. It is the partially abbreviate | omitted longitudinal cross-sectional view cut | disconnected. The process of pulling up the metal mask plate 1 in the vertical direction is shown, (a) is a longitudinal sectional view cut along the short direction of the through hole 3, and (b) is cut along the long direction of the through hole 3. FIG. The process which isolate | separated the sealing resin 3 of the piezoelectric substrate 120 side and the metal mask plate 1 side is shown, (a) is the longitudinal cross-sectional view cut | disconnected along the transversal direction of the through-hole 3, (b) is a through-passage. FIG. 4 is a partially omitted longitudinal sectional view cut along the longitudinal direction of a hole 3. It is a longitudinal cross-sectional view of the screen printing process which adheres sealing resin 106 to the circumference | surroundings of the electronic component 120 using the conventional metal mask plate 103. FIG. It is a longitudinal cross-sectional view which shows the state which pulled up the metal mask plate 103. FIG. It is a longitudinal cross-sectional view which shows the state which pulled apart the metal mask plate 103 from the sealing resin 106 adhering to the electronic component 120 completely.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal mask plate for screen printing 1A Upper metal mask plate 1B Lower metal mask plate 2 Through hole 2A Upper large diameter hole 2B Lower small diameter hole 3 Sealing resin 4 Resin inflow space 6 Step part 100 Touch panel input device 100A Operation area 102 Touch panel (Support substrate)
120 Electronic components (piezoelectric substrates)

Claims (3)

A through hole (2) for accommodating the entire electronic component (120) mounted on the substrate (102) is formed, and the periphery of the electronic component (120) and the through hole ( 2) After the sealing resin (3) is filled into the resin inflow space (4) formed between the substrate and the substrate (102), the sealing resin (3) is removed around the electronic component (120). A metal mask plate for screen printing to be attached,
Outside the contour projected onto the substrate (102) of the electronic component (120) on the metal mask plate (1) for screen printing that is thicker than at least the height of the electronic component (120) mounted on the substrate (102), The lower small-diameter hole (2B) having an interval corresponding to the thickness (d) of the sealing resin (3) to be attached communicates with the lower small-diameter hole (2B) above the lower small-diameter hole (2B). A through hole (2) including an upper large-diameter hole (2A) having an outline including the outline of the hole (2B) is formed, and a lower small-diameter hole (2B) and an upper large-diameter hole (2) in the through-hole (2) are formed. A metal mask plate for screen printing, wherein a step (6) is formed at the boundary of 2A). The metal mask plate for screen printing (1) includes a lower metal mask plate (1B) in which a lower small-diameter hole (2B) is formed corresponding to the mounting part of the electronic component (120), and a lower metal mask plate (1B). The upper layer metal mask plate (1A) formed with an upper large-diameter hole (2A) that is laminated above and communicates with the lower small-diameter hole (2B). Metal mask version. The screen according to claim 1 or 2, wherein the electronic component is a piezoelectric substrate (120) that is fixed to the touch panel (102) and vibrates when a pressing operation on the touch panel (102) is detected. Metal mask version for printing.

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