JP2011150200A - Display manufacturing method, display and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a display minimizing its visibility drop due to the cover set on its display surface. <P>SOLUTION: The manufacturing method includes a step S6 of adhering together a cover 10 having a printing surface printed by using an ink diluted in an ink diluting solvent and a display surface of the display panel 20 to display image information by using a thermosetting joining material 30 having a hardening temperature Tc lower than an evaporating temperature Ta of the ink diluting solvent; and a step S9 of thermosetting the joining material at the temperature Tc lower than the evaporation temperature Ta of the ink diluting solvent. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a display device such as a liquid crystal display device or an organic EL display device, a display device manufactured using the display device, and an electronic apparatus.

  On the display surface of a display panel such as a liquid crystal display panel or an organic EL display panel, a transparent cover member made of tempered glass or acrylic resin is often bonded and disposed for the purpose of preventing scratches and ensuring strength (for example, patents). Document 1, Non-Patent Document 1, etc.).

  In Patent Document 1, a transparent cover member made of acrylic resin or the like is disposed on the display surface of the display panel, and this cover member is displayed using a transparent and adhesive material such as a silicon film made of silicon resin. Display devices that adhere to surfaces have been proposed.

  In Non-Patent Document 1, a transparent cover member made of tempered glass or the like is disposed on the display surface of the display panel, and a resin (bonding agent) having both ultraviolet curing reaction characteristics and thermosetting reaction characteristics is used. A method for adhering the cover member to the display surface has been proposed. In this method, after the display surface of the display panel and the cover member are bonded to each other with the bonding agent interposed therebetween, ultraviolet rays are irradiated from the surface of the cover member, and heat is further applied to cure the bonding agent, thereby displaying the display. The surface and the cover member are bonded. By this method, for example, even if it is difficult to cure the bonding agent only by irradiation with ultraviolet rays as a result of printing on the back surface (the surface on the display panel side) of the cover member, the bonding agent can be made more by applying heat thereafter. It can be cured and the display surface and the cover member can be more reliably bonded.

JP 2008-257061 A

"Improves visibility and impact resistance at the same time, commercializes an optical resin with elastic properties for liquid crystal / organic EL displays", [online], April 16, 2008, Sony Chemical & Information Device Corporation, [ Search October 1, 2009], Internet <URL: http://www.sonycid.jp/news/news08007.html>

  By the way, when printing is performed on the back surface of the cover member, there is a possibility that a small amount of the diluted solvent of the ink agent may remain on the printing surface without being sufficiently vaporized. At this time, for example, in the method of Non-Patent Document 1, in the step of thermosetting the bonding agent between the display surface of the display panel and the cover member, the diluting solvent is vaporized so that it is between the cover member and the bonding agent. Bubbles may be generated. On the other hand, Patent Document 1 does not describe a method for producing an adhesive film, but if the same method as Non-Patent Document 1 is used, bubbles may be generated in exactly the same manner. Also, if an adhesive film prepared in advance is used, air may enter when the display panel and the cover member are bonded due to the difficulty in handling such a film.

  On the other hand, it is desirable that the cover member is parallel on both surfaces and is flat without warping on each surface. When the cover member whose both surfaces are not parallel is used, for example, in the step of bonding the display surface of the display panel and the cover member as in Non-Patent Document 1, the bonding agent between the display surface and the cover member is from one side. There is a risk of problems such as leakage and lack of bonding agent on the other side. In addition, when a cover member that is warped and not flat, or that warps easily due to environmental conditions such as temperature and humidity, the cover member bends due to changes in environmental conditions, for example, during manufacturing or product use. There is also a possibility that the adhesion between the display surface of the display panel and the cover member may be peeled off.

  In this way, when bubbles are generated between the cover member and the bonding agent, the bonding agent between the display surface of the display panel and the cover member is insufficient, or the bonding between the display surface and the cover member is peeled off, When the appearance of the device deteriorates and further reaches the effective display area of the display panel, the visibility of the display device is lowered.

  The present invention has been made in view of such problems, and a display device manufacturing method and a display that minimize deterioration in product appearance quality and display surface visibility caused by a joining process between a cover member and a display panel. It is to provide an apparatus and an electronic device.

  The manufacturing method of the display device of the present invention includes a bonding process and a thermosetting process. In the laminating step, the printing surface of the cover member having a printing surface printed using the ink agent diluted with the ink dilution solvent and the display surface of the display panel displaying the image information are separated from the vaporization temperature of the ink dilution solvent. Bonding is performed using a thermosetting bonding agent having a low curing temperature. In the thermosetting step, the bonding agent is thermoset at a temperature lower than the vaporization temperature of the ink dilution solvent.

  A first display device of the present invention has a cover member having a printing surface printed using an ink agent diluted with an ink dilution solvent, and a display surface for displaying image information. And a display panel bonded to the printed surface of the cover member using a thermosetting bonding agent having a curing temperature lower than the vaporization temperature of the diluting solvent.

  An electronic apparatus according to the present invention includes the above-described display device according to the present invention.

  In the manufacturing method of the display device of the present invention, the first display device and the electronic apparatus manufactured using the display device, the cover member and the display panel are bonded to each other by thermosetting the bonding agent. Even if the ink dilution solvent remains on the printing surface by lowering the temperature at the time of thermal curing below the vaporization temperature of the ink dilution solvent used on the printing surface of the cover member, The bonding agent can be thermally cured without vaporizing the ink dilution solvent.

  The cover member may be made of an acrylic resin plate. In that case, it is desirable to use a water absorption rate of 1.0% or less. Thereby, the shape change of the cover plate due to water absorption becomes small, and the adhesion between the cover member and the display panel is difficult to peel off.

  When a display panel having a terminal portion on one side and a cover member having a non-uniform thickness are used, the direction of one side where the terminal portion of the display panel is disposed and the thickness of the cover member are determined in the bonding step. It is desirable that the display panel and the cover member are bonded together in a state in which the direction of the larger one side is matched. At this time, it is desirable that the surface opposite to the printing surface of the cover member and the surface opposite to the display surface of the display panel are bonded to each other in parallel. Further, it is desirable that the cover member is composed of a flatness of each surface and a parallelism of both surfaces of 50 [μm] or less. As a result, the bonding agent before thermosetting in the bonding process is less likely to leak from between the cover member and the display panel, or is less likely to be insufficient between the cover member and the display panel.

  A second display device of the present invention includes a display panel having a terminal portion on one side, and a cover member having a non-uniform thickness and bonded to the display surface of the display panel with a bonding agent. In particular, in the display panel and the cover member, the direction of one side where the terminal portion of the display panel is arranged coincides with the direction of one side where the thickness of the cover member is larger, and the terminal portion is arranged. It is arrange | positioned so that the thickness of the bonding agent in one side may become thinner than the thickness of the bonding agent in the one side on the opposite side to the terminal part. In particular, it is desirable that the surface opposite to the printing surface of the cover member and the surface opposite to the display surface of the display panel are parallel to each other.

  In the second display device of the present invention, the bonding agent before thermosetting in the bonding step is less likely to leak from between the cover member and the display panel, or less likely to be insufficient between the cover member and the display panel. .

  According to the display device manufacturing method, the first display device, and the electronic apparatus of the present invention, since a thermosetting bonding agent having a curing temperature lower than the vaporization temperature of the ink dilution solvent is used, bubbles are generated. Since the cover plate is less likely to occur and the shape change due to water absorption is small, the adhesion between the display panel and the cover member is difficult to peel off, and the reduction in visibility due to the joining process can be minimized.

  Further, according to the second display device of the present invention, since the display device is configured in consideration of the orientation of the display panel and the cover member, it is difficult for the bonding agent between the display panel and the cover member to be excessive or insufficient. Therefore, the deterioration of the product appearance quality and the visibility of the display surface due to this can be minimized.

4A and 4B are a plan view and a cross-sectional view illustrating a configuration example of a display device according to an embodiment of the invention. It is a flowchart showing an example of the assembly process of the display apparatus shown in FIG. It is the top view and photograph showing an example when a bubble generate | occur | produces in the display apparatus shown in FIG. In the display apparatus shown in FIG. 1, it is sectional drawing showing the state of the bonding agent by the direction of a cover member and a display panel. It is a schematic diagram showing the definition of the parallelism and flatness of a cover member shown in FIG. In the display apparatus shown in FIG. 1, it is a table | surface showing the relationship between the orientation of a cover member and a display panel, the flatness and flatness of a cover member, and an appearance defect. In the display apparatus shown in FIG. 1, it is a table | surface showing the relationship between the flatness and flatness of a cover member, and an external appearance defect. It is a plot figure showing the time change of a water absorption and a dimensional change rate when water is absorbed in the cover member shown in FIG. It is a perspective view showing the appearance composition of application example 1 among display devices to which an embodiment is applied. 12 is a perspective view illustrating an appearance configuration of an application example 2. FIG. 12 is a perspective view illustrating an appearance configuration of an application example 3. FIG. 14 is a perspective view illustrating an appearance configuration of an application example 4. FIG. FIG. 10 is a front view, a side view, a top view, and a bottom view illustrating an appearance configuration of an application example 5.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The description will be given in the following order.
1. Embodiment 2. FIG. Example 3 Application examples

<1. Embodiment>
[Configuration example]
1A and 1B show a configuration example of a display device according to an embodiment of the present invention. FIG. 1A is a plan view of the display device 1, and FIG. A schematic sectional structure in a direction is shown. The display device manufacturing method according to the embodiment of the present invention is embodied by the present embodiment, and will be described together. The display device 1 includes a cover member 10, a display panel 20, and a bonding agent 30.

  The cover member 10 is adhesively arranged on the surface of the display surface 21 (described later) of the display panel 20 and is made of a transparent resin plate such as an acrylic resin plate, for example, to prevent damage to the display surface and ensure strength. It has the function to do. As its properties, those having good parallelism on both surfaces and flatness on each surface are desirable. Moreover, it is preferable that the rate of dimensional change due to water absorption is low and the coefficient of linear expansion due to heat is low. In addition to acrylic resin, polyethylene resin (PE), polycarbonate resin (PC), cyclic olefin copolymer (COC), and the like can be used as the material for the cover member 10.

  On the back surface (the surface on the display panel 20 side) of the cover member 10, the print region 11 is provided outside the region corresponding to the effective display region A of the display panel 20. As the ink agent used in the printing region 11, for example, a POS screen ink (produced by Teikoku Ink Manufacturing Co., Ltd.) diluted with a hydrocarbon solvent can be used. Further, as will be described later, the hydrocarbon solvent has a vaporization temperature (ink solvent vaporization temperature Ta) higher than the thermosetting temperature of the bonding agent 30 (bonding agent thermosetting temperature Tc, for example, 80 degrees) (Tc < Ta), for example, toluene (Ta = 10.6 degrees) or xylene (Ta = 139 degrees) can be used.

  The display panel 20 is a panel that displays an arbitrary image, and the image displayed on the display surface 21 of the display panel 20 is visible from the outside through the bonding agent 30 and the cover member 10. As the display panel 20, for example, a liquid crystal display panel using a liquid crystal display element, an organic EL display panel using an organic EL element, or the like can be used. A terminal portion 22 is provided on one side of the display panel 20 so that an image signal or the like corresponding to an image to be displayed is supplied from the outside. This terminal part 22 is comprised by the flexible substrate etc., for example. The display panel 20 may be a display panel having a touch detection function in addition to the display function.

  The bonding agent 30 is for bonding the display surface 21 of the display panel 20 and the cover member 10 together. The bonding agent 30 has both an ultraviolet curing reaction characteristic that is cured by irradiating ultraviolet rays and a thermosetting reaction characteristic that is cured by applying heat, and the display surface 21 and the cover member 10 are cured by curing. Are to be bonded. As the bonding agent 30, for example, SVR1400H (manufactured by Sony Chemical & Information Device Co., Ltd.) can be used. The bonding agent thermosetting temperature Tc of this SVR1400H is 80 degrees.

[Example of manufacturing method]
Next, a method for manufacturing the display device 1 according to the present embodiment will be described.

  FIG. 2 shows an example of a flowchart of the assembly process of the display device 1. In this process, the cover member 10 is cut out from a large acrylic resin plate, and the display panel 20 and the cover member 10 manufactured in a separate process are bonded and bonded together using a bonding agent 30, thereby displaying the display. The apparatus 1 is assembled.

  First, the printing region 11 is printed using a predetermined ink agent on a large acrylic resin plate capable of simultaneously manufacturing a plurality of cover members 10 (step S1). As the ink agent, in this example, a POS screen ink (produced by Teikoku Ink Manufacturing Co., Ltd.) diluted with toluene (ink solvent vaporization temperature Ta = 110.6 degrees) is used.

  Next, the ink printed in step S1 is thermally cured (step S2). The temperature applied during the heat curing (ink thermosetting temperature Tb) is 75 degrees. The ink thermosetting temperature Tb is set in consideration of the heat resistance of the acrylic resin plate.

  Next, the cover member 10 is cut out from the large acrylic resin plate, and its outer shape is processed (step S3).

  Next, the thickness of the cover member 10 is measured (step S4). At that time, the thicknesses of the two opposing short sides of the cover member 10 are also measured to determine which of the short sides is thicker.

  Next, the bonding agent 30 is applied to the back surface of the cover member 10 (the surface on the display panel 20 side in FIG. 1) (step S5). In this example, SVR1400H (manufactured by Sony Chemical & Information Device Co., Ltd., bonding agent thermosetting temperature Tc = 80 degrees) is used as the bonding agent 30.

  Next, the cover member 10 and the display panel 20 are bonded together with the bonding agent 30 (step S6). At that time, based on the result of the thickness measurement of the cover member 10 performed in step S4, the cover member 10 is arranged so that the thicker one of the opposed short sides of the cover member 10 is on the terminal portion 22 side of the display panel 20. Deploy. Further, the cover member 10 is bonded so that the front surface of the cover member 10 and the back surface of the display panel 20 are parallel to each other. Thereafter, the position is finely adjusted. In this fine adjustment, for example, adjustment is made so that the printing portion 11 of the cover member 10 and the printing portion 11 of the display panel 20 are in an appropriate positional relationship.

  Next, the bonded cover member 10 and the display panel 20 are irradiated with ultraviolet rays from the surface of the cover member 10, and particularly in a region corresponding to the effective display region A (a region where the print site 11 of the cover member 10 is not present). An ultraviolet curing is performed for a certain bonding agent 30 (step S7).

  Next, heat is applied to the cover member 10 and the display panel 20, and the entire bonding agent 30 is thermally cured (step S8). The temperature applied during the heat curing (bonding agent heat curing temperature Tc) is 80 degrees, which is set lower than the ink solvent vaporization temperature Ta. By this process, the bonding agent 30 is cured in the region with the print region 11 in addition to the region corresponding to the effective display region A (the region without the print region 11) performed in step S7, and the display panel 20 and the cover member 10 are bonded together. Note that the thickness when the bonding agent 30 is cured is about 150 μm.

  Thus, the assembly of the display device 1 is completed.

[Action / Effect]
Next, the operation of the display device 1 manufactured by such a manufacturing method will be described.

(Relationship between ink solvent vaporization temperature Ta and bonding agent thermosetting temperature Tc)
In the display device 1, the bonding agent 30 has a bonding agent thermosetting temperature Tc (80 degrees) lower than the ink solvent vaporization temperature Ta (110.6 degrees) of the ink agent (Tc <Ta). Ink agent is used. As a result, even if the diluted solvent of the ink agent does not sufficiently evaporate in Step S2 and remains in a small amount in the print site 11, the evaporation of the diluted solvent is performed in Step S8 (thermosetting of the bonding agent 30) as shown below. Therefore, generation of bubbles between the cover member 10 and the bonding agent 30 can be minimized.

  Here, a case (comparative example) where the bonding agent thermosetting temperature Tc is higher than the ink solvent vaporization temperature Ta (Tc> Ta) will be described. At this time, in step S8 (thermosetting of the bonding agent 30), bubbles may be generated in the vicinity of the printing region 11 due to the evaporation of the diluted solvent of the ink agent.

  3A and 3B show an example in the case where bubbles are generated in the display device. FIG. 3A is a plan view of the display device 1 and FIG. 3B is an enlarged photograph of a portion where bubbles are generated. This display device is assembled based on the flow chart of the assembly process of the display device shown in FIG. 2, but POS screen ink (manufactured by Teikoku Ink Manufacturing Co., Ltd.) is used as the ink agent used in printing in step S1. Is diluted with ethyl acetate (ink solvent vaporization temperature Ta = 77.1 degrees). That is, in this display device, the bonding agent 30 is such that the bonding agent thermosetting temperature Tc (80 degrees) of the bonding agent 30 is higher than the ink solvent vaporization temperature Ta (77.1 degrees) of the ink agent (Tc> Ta). Ink agent is used. At this time, bubbles are generated between the cover member 10 and the bonding agent 30 as shown in FIG. 3B in the area around the print region 3 shown in FIG. It extends from the vicinity of the print region 11 to the effective display area A.

  These bubbles are caused by the diluted solvent of the ink agent. That is, the air bubbles are printed because the adhesive thermosetting temperature Tc (80 degrees) in step S8 (thermosetting of the adhesive 30) is higher than the ink solvent vaporization temperature Ta (77.1 degrees) (Tc> Ta). This is caused by the evaporation of the diluted solvent of the ink agent remaining in a small amount in the portion 11.

  When bubbles are generated in this way, the appearance of the display device is deteriorated, resulting in poor appearance. In particular, as shown in FIG. 3B, when the bubbles reach the effective display area A, the visibility as a display device is significantly deteriorated.

  On the other hand, in the present embodiment, since the bonding agent thermosetting temperature Tc is lower than the ink solvent vaporization temperature Ta (Tc <Ta), even if heat is applied in step S8 (thermosetting of the bonding agent 30). The evaporation of the diluted solvent of the ink agent remaining in a small amount at the printing site 11 can be suppressed, and the generation of such bubbles can be minimized.

(Direction between cover member 10 and display panel 20)
In the display device 1, when the cover member 10 and the display panel 20 are bonded together in step S <b> 6, the thicker cover member 10 of the opposing short sides of the cover member 10 is closer to the terminal portion 22 side of the display panel 20. It is arranged to be. Thereby, as shown below, the overflow of the bonding agent 30 between the cover member 10 and the display panel 30 is less likely to occur, and the shortage of the bonding agent 30 due to the overflow is less likely to occur.

  In general, the parallelism of both sides of the resin plate is not as excellent as that of the glass plate. Therefore, both sides of the cover member 10 using such a resin plate are slightly shifted from parallel. This characteristic affects when the cover member 10 and the display panel 20 are bonded together in step S6. That is, in step S6, as described above, it is generally desired that the front surface of the cover member 10 and the back surface of the display panel 20 be parallel in view of the required specifications regarding the external dimensions of the display device 1. When both surfaces are not parallel, the interval between the cover member 10 filled with the bonding agent 30 and the display panel 20 becomes non-uniform. Thereby, there exists a possibility that the bonding agent 30 may leak or be insufficient.

  FIG. 4 shows the state of the bonding agent 20 depending on the orientation of the cover member 10 and the display panel 20. FIG. 4A shows a state in which the cover member 10 is thicker among the opposing short sides of the cover member 10. An example (comparative example, hereinafter, arrangement A) when arranged so as to be opposite to the terminal portion 22 is shown, and (B) shows that the cover member 10 is thicker among the short sides facing the cover member 10. An example (embodiment, hereinafter, arrangement B) when arranged so as to be on the terminal portion 22 side of the display panel 20 is shown.

  In the arrangement A which is a comparative example, as illustrated in FIG. 4A, when the cover member 10 and the display panel 20 are bonded together in step S <b> 6, the bonding agent 30 overflows on the side opposite to the terminal portion 22. Yes. In the arrangement A, the cover member 10 is thicker on the side opposite to the terminal portion 22, and therefore the distance between the cover member 10 filled with the bonding agent 30 and the display panel 20 is different from the terminal portion 22. This is due to narrowing on the opposite side. A part of the overflowing bonding agent 30 reaches the side surface of the display panel 20. Since the bonding agent 30 is cured in steps S <b> 8 and S <b> 9, this overflowing affects the outer dimensions of the display device 1. Alternatively, if this overflow is removed before curing, the number of steps increases.

  As shown in FIG. 4A, the bonding agent 30 is insufficient between the cover member 10 and the display panel 20 on the terminal portion 22 side of the display device 1. This is due to the following two reasons. That is, the first reason is that the cover member 10 is thin on the terminal portion 22 side, and therefore the distance between the cover member 10 filled with the bonding agent 30 and the display panel 20 is the terminal portion 22 side. It is because it spreads in. The second reason is that the amount of the bonding agent 30 existing between the cover member 10 and the display panel 20 decreases due to overflow of the bonding agent 30 on the opposite side of the terminal portion 22. .

  As described above, in the arrangement A, overflow of the bonding agent 30 occurs on the side opposite to the terminal portion 22 of the display device 1, and bonding is performed between the cover member 10 and the display panel 20 on the terminal portion 22 side. The agent 30 is insufficient. The overflow of the bonding agent 30 causes the appearance of the display device to deteriorate, resulting in poor appearance. Further, the shortage of the bonding agent 30 deteriorates the visibility as a display device particularly when the shortage of the bonding agent 30 reaches the effective display area A as shown in FIG.

  On the other hand, in the arrangement B according to the present embodiment, as shown in FIG. 4B, when the cover member 10 and the display panel 20 are bonded together in step S6, the bonding agent 30 overflows to the terminal portion 22 side. ing. This is because, in the arrangement B, the cover member 10 is thicker on the terminal portion 22 side, and thus the interval between the cover member 10 filled with the bonding agent 30 and the display panel 20 is narrowed. . Part of the overflowing bonding agent 30 reaches the vicinity of the terminal portion 22. However, in the arrangement B (FIG. 4B), unlike the arrangement A (FIG. 4A), the bonding agent 30 overflows because the terminal portion 22 exists at the destination where the bonding agent 30 overflows. The amount is suppressed. Further, since the terminal portion 22 exists, even if the bonding agent 30 overflows, the influence on the outer dimensions and the like is less than that of the arrangement A.

  On the side opposite to the terminal portion 22 of the display device 1, the bonding agent 30 is insufficient between the cover member 10 and the display panel 20 as shown in FIG. This is due to the following two reasons as in the case of the arrangement A. That is, the first reason is that the cover member 10 is thin on the side opposite to the terminal portion 22, and thus the interval between the cover member 10 filled with the bonding agent 30 and the display panel 20 is widened. Because. The second reason is that the amount of the bonding agent 30 existing between the cover member 10 and the display panel 20 decreases due to overflow of the bonding agent 30 on the terminal portion 22 side. However, as described above, in the arrangement B, the amount of the overflow of the bonding agent 30 is suppressed compared to the arrangement A. Therefore, the influence of the second reason in the arrangement B is more than the influence of the second reason in the arrangement A. Will also be small. That is, in the arrangement B, the shortage of the bonding agent 30 between the cover member 10 and the display panel 20 is less likely to occur than in the arrangement A.

  As described above, in the display device 1 according to the present embodiment, since the orientation of the cover member 10 and the display panel 20 is the arrangement B, the amount of overflow and deficiency of the bonding agent 30 is larger than that in the arrangement A. And the appearance of the display device is hardly deteriorated. Furthermore, the possibility that the shortage of the bonding agent 30 occurs in the effective display area A is reduced, and the possibility that the visibility as a display device is deteriorated is reduced.

  2, the cover member 10 and the display panel 20 are bonded so that the front surface of the cover member 10 and the back surface of the display panel 20 are parallel to each other. Here, the term “parallel” is not limited to perfect parallelism, but may be parallel to the extent that the required specifications for the display device 1 can be satisfied. That is, the front surface of the cover member 10 and the back surface of the display panel 20 may be slightly deviated from perfect parallel within the range of required specifications.

  This action is also affected by the parallelism of both surfaces of the cover member 10 described later and the flatness of each surface. That is, by using the cover member 10 with good parallelism and flatness, the overflow and shortage of the bonding agent 30 are less likely to occur.

(Parallelity and flatness of the cover member 10)
In the display device 1, the cover member 10 preferably has good parallelism on both surfaces and flatness on each surface. Specifically, both the parallelism P and the flatness S are preferably 50 μm or less. Below, the definition of parallelism P and flatness S will be described.

  5A shows the definition of the parallelism P of the cover member 10, and FIGS. 5B and 5C show the definition of the flatness S. FIG. These drawings are shown as schematic views using a cross section in the direction of arrows I-I of the cover member 10 in the display device 1 of FIG. In FIG. 5, for convenience of explanation, the cover member 10 is curved, and the front surface (upper surface) of the cover member 10 has a convex shape and the back surface (lower surface) has a concave shape.

  The parallelism P is an index indicating the parallelism of both surfaces of the cover member 10 as shown in FIG. That is, the parallelism P is in contact with the line LA1 connecting the corners A1 and A2 of the concave surface (shown as a line for the sectional view in FIG. 5), and the parallel and convex surface (line). This is defined as the distance between the line LA2 and the line LA3 when the line LA2 and the line LA3 parallel to these lines and passing through the corner A4 of the convex surface (line) are drawn. Therefore, it shows that both surfaces of the cover member 10 are parallel, so that the numerical value of the parallelism P is small.

  The flatness S is an index indicating the flatness of each surface of the cover member 10 as shown in FIGS. 5 (B) and 5 (C). That is, the flatness S is defined for each of the front surface and the back surface of the cover member 10. On the surface, as shown in FIG. 5 (B), the flatness S is parallel to the line LB1 connecting the corners B1 and B2 of the surface (shown as a line for the sectional view in FIG. 5). It is defined as the distance between the line LB1 and the line LB2 when the line LB2 in contact with the surface (line) is drawn. On the back surface, as shown in FIG. 5C, the flatness S is parallel to the line LC1 connecting the corners C1 and C2 of the back surface (line) and the back surface (line). It is defined as the distance between the line LC1 and the line LC2 when the line LC2 in contact with the line LC2 is drawn. Therefore, it shows that the surface of the cover member 10 is so flat that the numerical value of the flatness S is small.

  In the display device 1 according to the present embodiment, since the cover member 10 having excellent parallelism P and flatness S is used while considering the orientation of the cover member 10 and the display panel 20 described above, in step S6, When the cover member 10 and the display panel 30 are bonded together, the bonding agent 30 is unlikely to overflow and become insufficient.

(Water absorption rate of the cover member 10)
In the display device 1, the cover member 10 preferably has a low dimensional change rate due to water absorption. Specifically, it is desirable that the water absorption rate is 1.0% or less and the dimensional change rate is 0.12% or less. Here, the water absorption rate is defined as the change in weight of the cover member 10 due to water absorption divided by the weight before water absorption (during drying), and the dimensional change rate is the long side of the cover member 10 due to water absorption. Is defined as the change in length of the product divided by the length of the long side before water absorption (during drying).

  When the cover member 10 absorbs water, its volume expands, its shape changes, and deformation such as warping may occur. That is, the flatness of each surface deteriorates. Thereby, there exists a possibility that adhesion | attachment of the display surface 21 of the display panel 20 and the cover member 10 may peel off. When this peeling occurs, the appearance of the display device deteriorates, resulting in poor appearance. Further, when the peeling reaches the effective display area A, the visibility as a display device is also deteriorated.

  On the other hand, in the display device 1 of the present embodiment, the cover member 10 having a low dimensional change rate due to water absorption is used. For example, the surface of the cover member gets wet for a long time or has a high humidity of about 90%. Even in the environment, the amount of deformation of the cover member 10 is small. Therefore, the adhesion between the display surface 21 of the display panel 20 and the cover member 10 is unlikely to occur.

<2. Example>
Based on this embodiment, a display device was prototyped according to the flowchart of the assembly process of the display device shown in FIG. Examples thereof are shown below.

(Relationship between ink solvent vaporization temperature Ta and bonding agent thermosetting temperature Tc)
A display device was prototyped using two types of ink agents used in printing in step S1. That is, the ink agent A is a POS screen ink (manufactured by Teikoku Ink Manufacturing Co., Ltd.) diluted with toluene (ink solvent vaporization temperature Ta = 110.6 degrees), and the ink agent B is a POS screen ink (Imperial ink). Manufacture Co., Ltd.) is diluted with ethyl acetate (ink solvent vaporization temperature Ta = 77.1 degrees). On the other hand, in step S8, the temperature (bonding agent thermosetting temperature Tc) applied when the bonding agent 30 is thermally cured is set to 80 degrees. That is, the relationship between the bonding agent thermosetting temperature Tc and the ink solvent vaporization temperature Ta is Tc <Ta when the ink agent A is used, and Tc> Ta when the ink agent B is used.

  The display device was assembled using these two ink agents, and it was confirmed whether or not bubbles between the cover member 10 and the bonding agent 30 were generated in the effective display area A. As a result, the bubble generation rate when ink agent A was used was 3.3%, whereas when ink agent B was used, it was 63.5%.

  The bubbles generated when the ink agent B is used have a bonding agent thermosetting temperature Tc (80 degrees) higher than the ink solvent vaporization temperature Ta (77.1 degrees) (Tc> Ta). This is caused by the evaporation of the diluted solvent of the ink agent that remained in a small amount at the printing site 11 when heat was applied in the heat curing of No. 30.

  As described above, the generation of bubbles is suppressed by using the bonding agent 30 and the ink agent in which the bonding agent thermosetting temperature Tc of the bonding agent 30 is lower than the ink solvent vaporization temperature Ta of the ink agent (Tc <Ta). be able to.

(Direction of cover member 10 and display panel 20, parallelism P and flatness S)
Using the cover members 10 having various parallelisms P and flatnesses S, trial manufactures of display devices were performed in various orientations of the cover members 10 and the display panel 20.

  FIG. 6 illustrates the relationship between the thickness, the parallelism P, and the flatness S of the cover member 10 and the appearance defect. FIG. 7 shows the relationship between the parallelism P and flatness S of the cover member 10 and the appearance defect.

  In FIG. 6, the thickness D <b> 1 is a measured value of the thickness of the cover member 10 on the side opposite to the terminal portion 22, and the thickness D <b> 2 is a measured value of the thickness of the cover member 10 on the terminal portion 22 side. Here, the parallelism P is classified into the three ranks shown in FIG. 7 based on the above-described definition (FIG. 5A). That is, for the parallelism P, the parallelism rank P1 is 0 to 30 μm, the parallelism rank P2 is 30 to 50 μm, and the parallelism rank P3 is 50 μm or more. Here, the flatness S is classified into the three ranks shown in FIG. 7 based on the above-described definitions (FIGS. 5B and 5C). That is, the flatness S is 0 μm or more and 10 μm or less as flatness rank S1, 10 μm or more and 30 μm or less is flatness rank S2, and 30 μm or more is flatness rank S3. The appearance inspection result (bonding agent overflow) indicates the result of the appearance inspection regarding the overflowing of the bonding agent 30 performed after the assembly process shown in FIG. Specifically, the appearance inspection relating to the overflow of the bonding agent is performed by the bonding agent 30 filled between the cover member 10 and the display panel 20 from the terminal portion 22 side or the opposite side of the terminal portion 22. This is an inspection of whether or not it overflows. The inspection results satisfying the required specifications are indicated by ◯, and those not satisfying the required specifications are indicated by ×. The appearance inspection result (bonding agent shortage) indicates the result of the appearance inspection regarding the shortage of the bonding agent 30 performed after the assembly process shown in FIG. Specifically, in the appearance inspection regarding the lack of bonding agent, the bonding agent 30 filled between the cover member 10 and the display panel 20 is insufficient on the terminal portion 22 side or the opposite side to the terminal portion 22. The inspection results are indicated by ◯ when the inspection results satisfy the required specifications, and indicated by × when the inspection results do not satisfy the required specifications.

  Appearance defects tend to occur when thickness D1-thickness D2 is positive, as shown in FIG. That is, this state is a state in which the thicker cover member 10 is located on the opposite side to the terminal portion 22 of the display panel 20 among the opposing short sides of the cover member 10. This corresponds to (FIG. 4A). In this state, as described above, the bonding agent 30 may overflow to the side opposite to the terminal portion 22 and affect the external dimensions of the display device 1.

  The percentage in FIG. 7 indicates the defect rate of appearance inspection in each of the parallelism ranks P1 to P3 and the flatness ranks S1 to S3. As in the case of FIG. 6, the appearance inspection is performed for overflow and shortage of the bonding agent 30, and whether the inspection result satisfies the required specifications is judged as good or bad.

  As shown in FIG. 7, the appearance defect tends to occur when the parallelism P is large, and the parallelism P is preferably at least 50 μm or less (parallelism ranks P1 and P2). At this time, the appearance defect is not greatly affected by the flatness S, but the flatness S may be 50 μm or less (flatness ranks S1 and S2) as with the parallelism P.

  As described above, the orientation of the cover member 10 and the display panel 20 is as shown in the arrangement B, and the cover member 10 having both parallelism P and flatness S of 50 μm or less is used, thereby overflowing the bonding agent 30. And it becomes difficult to cause shortage.

(Water absorption rate of the cover member 10)
A display device was prototyped using two types of acrylic resin plates as the cover member 10. That is, the acrylic resin plate A (comparative example) has a general water absorption rate, and the acrylic resin plate B (the present embodiment) suppresses water absorption.

  FIG. 8A shows the time change of the water absorption rate when the cover member 10 is immersed in water alone, and FIG. 8B shows the dimensional change rate at that time. In addition, the temperature of the water to immerse is 25 degree | times. As shown in FIG. 8, when sufficient time has passed, the acrylic resin plate A has a water absorption rate of 1.7% and a dimensional change rate of 0.3%, while the acrylic resin plate B has a water absorption rate of The dimensional change rate is 1.0% and 1.0%. That is, the acrylic resin plate A has a higher water absorption rate than the acrylic material B, and the dimensional change rate is correspondingly higher.

  Using the acrylic resin plates A and B having such characteristics of water absorption and dimensional change rate, the display device was manufactured by the assembly process shown in FIG. 2 and placed in a high humidity environment of 90% humidity for a long time. Later, it was confirmed whether or not the display surface 21 of the display panel 20 and the cover member 10 were peeled off (a level affecting the appearance quality). As a result, the peeling occurrence rate when the acrylic resin plate A according to the comparative example was used was 100%, whereas it was 0% when the acrylic resin plate B according to the present embodiment was used. .

  The peeling when the acrylic resin plate A is used is caused by a dimensional change due to water absorption of the acrylic resin plate A. That is, this peeling occurs when the acrylic resin plate A absorbs water and its dimensions change and deformation such as warpage occurs in a high humidity environment.

  Thus, when the peeling of adhesion between the display surface 21 of the display panel 20 and the cover member 10 occurs, the appearance of the display device deteriorates and the appearance is deteriorated. Further, when the peeling reaches the effective display area A, the visibility as a display device is also deteriorated.

  On the other hand, when a resin plate that suppresses water absorption, such as the acrylic resin plate B, is used as the cover member 10, the amount of change in dimension due to water absorption is also reduced. Peeling can be suppressed.

<3. Application example>
Next, application examples of the display device described in the above embodiments and examples will be described with reference to FIGS. The display device in the above embodiment and the like can be applied to electronic devices in various fields such as a television device, a digital camera, a laptop personal computer, a mobile terminal device such as a mobile phone, or a video camera. In other words, the display device according to the above-described embodiment or the like can be applied to electronic devices in various fields that display an externally input video signal or an internally generated video signal as an image or video.

(Application example 1)
FIG. 9 illustrates an appearance of a television device to which the display device of the above-described embodiment or the like is applied. This television apparatus has, for example, a video display screen unit 510 including a front panel 511 and a filter glass 512, and the video display screen unit 510 is configured by the display device according to the above-described embodiment and the like. .

(Application example 2)
FIG. 10 illustrates an appearance of a digital camera to which the display device according to the above-described embodiment or the like is applied. The digital camera includes, for example, a flash light emitting unit 521, a display unit 522, a menu switch 523, and a shutter button 524, and the display unit 522 is configured by the display device according to the above-described embodiment and the like. Yes.

(Application example 3)
FIG. 11 illustrates an appearance of a notebook personal computer to which the display device of the above-described embodiment or the like is applied. This notebook personal computer has, for example, a main body 531, a keyboard 532 for inputting characters and the like, and a display unit 533 for displaying an image. The display unit 533 is a display according to the above-described embodiment and the like. It is comprised by the apparatus.

(Application example 4)
FIG. 12 shows the appearance of a video camera to which the display device of the above-described embodiment and the like is applied. This video camera has, for example, a main body 541, a subject shooting lens 542 provided on the front side surface of the main body 541, a start / stop switch 543 at the time of shooting, and a display 544. The display unit 544 is configured by the display device according to the above embodiment and the like.

(Application example 5)
FIG. 13 illustrates an appearance of a mobile phone to which the display device of the above-described embodiment or the like is applied. For example, the mobile phone is obtained by connecting an upper housing 710 and a lower housing 720 with a connecting portion (hinge portion) 730, and includes a display 740, a sub-display 750, a picture light 760, and a camera 770. Yes. The display 740 or the sub-display 750 is configured by the display device according to the above-described embodiment or the like.

  As described above, the present invention has been described with the embodiments and application examples thereof to the electronic device. However, the present invention is not limited to these embodiments and the like, and various modifications are possible.

  For example, in the above embodiment, the cover member is made of a resin plate such as an acrylic resin plate. However, the cover member is not limited to this, and is made of a glass plate such as tempered glass. But you can.

  For example, in the above-described embodiment, the ink thermosetting temperature Tb is lower than the ink solvent vaporization temperature Ta (Tb <Ta). However, the present invention is not limited to this. It may be higher than the solvent vaporization temperature Ta (Tb> Ta). This condition can be applied, for example, when a heat-resistant cover member such as a glass plate is used. In this case, since the diluted solvent of the ink agent is more easily vaporized in step S2 (thermosetting of the ink agent), and the amount remaining in the printing region 11 is smaller, heat is applied in step S9 (thermosetting of the bonding agent). Generation of bubbles when added can be further reduced.

DESCRIPTION OF SYMBOLS 1 ... Display apparatus, 3 ... Print site periphery, 10 ... Cover member, 11 ... Print site | part, 20 ... Display panel, 21 ... Display surface, 22 ... Terminal part, 30 ... Bonding agent, A ... Effective display area, Ta ... Ink Solvent vaporization temperature, Tb: ink thermosetting temperature, Tc: bonding agent thermosetting temperature, P: parallelism, S: flatness, D1, D2: thickness.

Claims (12)

The printing surface of the cover member having a printing surface printed using the ink agent diluted with the ink dilution solvent and the display surface of the display panel displaying the image information are lower than the vaporization temperature of the ink dilution solvent. A bonding step of bonding using a thermosetting bonding agent having a curing temperature;
And a thermosetting step of thermosetting the bonding agent at a temperature lower than the vaporization temperature of the ink dilution solvent. As the bonding agent, using a material that exhibits a photocuring reaction in addition to a thermosetting reaction,
The method for manufacturing a display device according to claim 1, further comprising a photocuring step of curing the bonding agent by light irradiation. The method for manufacturing a display device according to claim 1, wherein an acrylic resin plate is used as the cover member. The method for manufacturing a display device according to claim 3, wherein an acrylic resin plate having a water absorption rate of 1.0 [%] or less is used as the cover member. The display panel has a terminal portion on one side,
The cover member has a non-uniform thickness,
In the bonding step, the display panel and the cover member are aligned with a direction of one side where the terminal portion of the display panel is disposed and a direction of one side where the cover member is thicker. The manufacturing method of the display apparatus of Claim 1. The display according to claim 5, wherein in the bonding step, bonding is performed such that a surface of the cover member opposite to the printing surface and a surface of the display panel opposite to the display surface are parallel to each other. Device manufacturing method. The method for manufacturing a display device according to claim 6, wherein the flatness of each surface of the cover member and the parallelism of both surfaces are both 50 [μm] or less. A cover member having a printing surface printed using an ink agent diluted with an ink dilution solvent;
While having a display surface for displaying image information, this display surface was bonded to the printing surface of the cover member using a thermosetting bonding agent having a curing temperature lower than the vaporization temperature of the ink dilution solvent. A display device comprising a display panel. The display device according to claim 8, wherein the display panel has a touch detection function in addition to a display function. A processing unit for performing a predetermined process;
A display device for displaying information generated by the processing in the processing unit,
The display device
A cover member having a printing surface printed using an ink agent diluted with an ink dilution solvent;
While having a display surface for displaying image information, this display surface was bonded to the printing surface of the cover member using a thermosetting bonding agent having a curing temperature lower than the vaporization temperature of the ink dilution solvent. Electronic devices including display panels. A display panel having a terminal portion on one side;
A cover member that has a non-uniform thickness and is bonded to the display surface of the display panel by a bonding agent;
The direction of one side where the terminal portion of the display panel is arranged coincides with the direction of one side where the thickness of the cover member is larger, and
The thickness of the said bonding agent in the one side where the said terminal part is arrange | positioned is thinner than the thickness of the said bonding agent in the one side on the opposite side to the said terminal part. The display device according to claim 11, wherein a surface of the cover member opposite to the printing surface and a surface of the display panel opposite to the display surface are parallel to each other.

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