Display device and method for manufacturing a display device

Abstract

The present invention provides a display device and a method for manufacturing a display device, which prevent the adhesive layer from overflowing at the outer periphery of the display cell by controlling the amount of transparent optical adhesive that constitutes the adhesive layer formed between the cover plate and the display cell. [Solution] A glass cover plate 20 and an elastomer frame member 10 are formed in close contact using a glass insert in-mold method. A weir portion 14 is formed protruding from the inner surface 14 of the frame member 10, and a weir end surface 14a is formed at the boundary with the inner surface 23 of the cover plate 20. The transparent optical adhesive applied to the inner surface 23 of the cover plate 20 can be blocked by the weir end surface 14a, preventing the adhesive layer 60a from overflowing into area (ii) in order to bond the display cell 30.

Description

Technical Field

[0001] The present invention relates to a display device in which a cover plate is fixed to a window surrounded by a frame member, and a display cell is fixed to the inner surface of the cover plate via an adhesive layer formed of an optically transparent adhesive, and a method for manufacturing the display device.

Background Art

[0002] In the display device described in FIG. 3 of Patent Document 1, a stepped portion is formed on the outer peripheral portion of a protective plate such as glass, a step is formed around the opening of the device body cover, and the stepped portion of the protective plate and the step of the device body cover are joined and fixed with an adhesive tape. A touch panel of a liquid crystal display panel is joined to the back surface of the protective plate via an optically elastic resin.

[0003] Patent Document 2 describes a touch sensor combined with a display device. In this touch sensor, a cover panel such as glass and a first wiring body are overlapped. The first wiring body is formed by overlapping a first resin, a second resin, and a third resin, and conductor portions are provided between the first resin and the second resin and between the second resin and the third resin. The third resin of the first wiring body is joined to the cover panel via a transparent adhesive. A second wiring body, which is a part of a flexible wiring board, is joined to a second conductor portion provided in the second resin layer by a conductive adhesive portion, and further, a sealing resin for covering the exposed terminal portion is provided. In the structure shown in FIG. 5, a corner portion (555) is formed in the third resin, and the spread of the sealing resin toward the cover panel is blocked. In the structure shown in FIG. 14, a groove portion (537) is formed in the third resin, and the spread of the sealing resin is blocked.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] The display device described in Figure 3 of Patent Document 1 has a liquid crystal display panel touch panel bonded to the back surface of a protective plate via an optically elastic resin. When OCR (Optical Clear Resin) is used as the optically elastic resin, it is necessary to properly control the application area and amount of liquid OCR. If the amount of OCR is not applied properly, and the process of bonding the touch panel and protective plate is carried out after applying and partially curing the OCR, the OCR will remain partially cured on the inside of the device body cover, raised by surface tension, and the outer edge of the touch panel will easily come into contact with the raised OCR. As a result, assembly becomes impossible unless the touch panel is made to a considerably small size. Furthermore, even if a process of bonding the touch panel and protective plate while the OCR is still uncured is adopted, if the amount of OCR applied is not proper, the OCR will flow out around the touch panel.

[0006] Patent Document 2 describes a technical means for preventing the sealing resin from spreading by forming corners (555) and grooves (537) in a third resin that comes into contact with the sealing resin covering the exposed terminal portion. Even if the technical means described in Patent Document 2 is applied to the display device of Patent Document 1, it is difficult to completely eliminate the phenomenon of OCR overflowing and remaining around the touch panel, as is clear from Figures 5 and 14 of Patent Document 2.

[0007] The present invention aims to solve the above-mentioned conventional problems and to provide a display device and a method for manufacturing a display device that can control the amount of transparent optical adhesive applied to constitute the adhesive layer formed between the cover plate and the display cell, thereby preventing the adhesive layer from overflowing at the outer periphery of the display cell. [Means for solving the problem]

[0008] The present invention relates to a display device comprising a frame member, a glass cover plate fixed to the frame member, an adhesive layer formed on the inner surface of the cover plate that is visible in a window surrounded by the frame member, and a display cell fixed to the inner surface via the adhesive layer, The frame member has an inner surface surrounding the window, a weir portion projecting from the inner surface toward the window, and a weir end surface that is part of the weir portion and is continuous around the entire circumference of the window at the boundary with the inner surface of the cover plate. The adhesive layer is characterized by being formed in contact with the weir end surface by an optically transparent adhesive applied to the inner surface of the cover plate.

[0009] The display device of the present invention can be configured such that the frame member is formed from a synthetic resin material and is in close contact with the cover plate.

[0010] The display device of the present invention is such that the front surface of the display cell facing the cover plate is located rearward from the weir end surface, away from the cover plate.

[0011] In the present invention, it is preferable that the adhesive layer is not present between the side end face of the display cell and the inner surface of the frame member.

[0012] The present invention relates to a method for manufacturing a display device having a frame member, a glass cover plate fixed to the frame member, an adhesive layer formed on the inner surface of the cover plate that is visible in a window surrounded by the frame member, and a display cell fixed to the inner surface via the adhesive layer, The process involves using a glass insert in-mold method to mold the frame member to the cover plate using a synthetic resin material, In the above step, the frame member is formed with an inner surface surrounding the window, a weir portion projecting from the inner surface toward the inside of the window, and a weir end surface which is a part of the weir portion and is continuous around the entire circumference of the window at the boundary with the inner surface of the cover plate. The present invention is characterized by damming the liquid optically transparent adhesive applied to the inner surface of the cover plate at the dam end surface, thereby curing the optically transparent adhesive and forming the adhesive layer.

[0013] In the glass insert in-mold method for manufacturing the display device of the present invention, a protective sheet is attached to the inner surface of the cover plate, and the frame member is formed in close contact with the outer edge of the protective sheet and the outer edge of the protective sheet. It is preferable to peel the protective sheet from the inner surface of the cover plate to form the weir end surface.

[0014] The present invention provides a method for manufacturing a display device, in which the front surface of the display cell facing the cover plate is positioned rearward from the weir end surface, away from the cover plate, and the display cell is fixed to the inner surface of the cover plate.

[0015] In the method for manufacturing the display device of the present invention, it is preferable that when the display cell is fixed to the inner surface of the cover plate, the adhesive layer is not present between the side end surface of the display cell and the inner surface of the frame member. [Effects of the Invention]

[0016] The present invention allows for control over the amount of transparent optical adhesive that constitutes the adhesive layer formed between the cover plate and the display cell, thereby preventing the adhesive layer from overflowing around the outer periphery of the display cell, or preventing interference between the partially cured transparent optical adhesive and the display cell. [Brief explanation of the drawing]

[0017] [Figure 1] A perspective view of a display device according to an embodiment of the present invention, viewed from the front. [Figure 2] A partial cross-sectional view of the display device according to an embodiment of the present invention, taken by cutting along the line II-II in Figure 1. [Figure 3] This shows a method for manufacturing a display device according to an embodiment of the present invention, and a partial cross-sectional view of a cover plate having a protective sheet. [Figure 4]It shows a method for manufacturing a display device according to an embodiment of the present invention, and is a partial cross-sectional view showing a state in which a cover plate is held in a mold in a glass insert in-mold process. [Figure 5] It shows a method for manufacturing a display device according to an embodiment of the present invention, and is a partial cross-sectional view showing a state in which molten resin is injected into a cavity in a glass insert in-mold process. [Figure 6] It shows a method for manufacturing a display device according to an embodiment of the present invention, and is a partial cross-sectional view showing a process of applying a liquid optically transparent adhesive to the inner surface of a cover plate. [Figure 7] It shows a method for manufacturing a display device according to an embodiment of the present invention, and is a partial cross-sectional view showing a process of joining a display cell to the inner surface of a cover plate. [Figure 8] It shows a method for manufacturing a display device according to an embodiment of the present invention, and is a partial cross-sectional view showing a completed state in which a display cell is joined to the inner surface of a cover plate.

Embodiments for Carrying Out the Invention

[0018] The overall structure of the display device 1 according to an embodiment of the present invention is shown in FIG. 1, and a partial cross-sectional view of the display device 1 is shown in FIG. 2. The display device 1 of the embodiment is for vehicle use. However, the display device 1 may be used for other purposes than vehicle use, such as for game devices, theaters, portable devices, etc. With the display device 1 as a reference, the Y1 - Y2 direction is the front - rear direction, the Y1 direction is the front or outer side, and the Y2 direction is the rear or inner side. The X1 - X2 direction is the lateral direction. In FIG. 2, regarding the lateral direction, the X1 direction is the inner side of the device and the X2 direction is the outer side of the device. The Z1 - Z2 direction is the vertical direction.

[0019] The display device 1 has a frame member (bezel) 10, and the area enclosed by the frame member 10 is a window W. The window W refers to the area enclosed by the frame member 10 and where the frame member 10 is not present when viewed from the front (Y1 side) or rear (Y2 side). A cover plate 20, which is a glass plate, is fixed to the frame member 10. The frame member 10 is molded using the glass insert in-mold method, and the frame member 10 and the cover plate 20 are fixed in close contact with each other. The frame member 10 is made of a synthetic resin material, for example, a thermoplastic elastomer such as polyester or PVC.

[0020] As shown in Figure 2, the contact recess 11 of the frame member 10 and the outer periphery 21 of the cover plate 20 are in close contact with each other, fixing the frame member 10 and the cover plate 20, and most of the cover plate 20 is visible in the window W. The front surface 12 of the frame member 10 facing forward (in the Y1 direction) and the outer surface 22 of the cover plate 20 facing forward are on the same plane.

[0021] As shown in Figure 2, the frame member 10 has an inner surface 13 that faces the window W and surrounds the window W. The inner surface 13 is a plane perpendicular to the XZ plane and is formed continuously in the lateral direction (X1-X2 direction) and the vertical direction (Z1-Z2 direction). The window W is rectangular in shape, surrounded by the inner surface 13 extending in the lateral direction and the inner surface 13 extending in the vertical direction. In the cross-sectional view of Figure 2, the inner surface 13 may be inclined in the X2 direction, moving away from the window W towards the rear (Y2 direction), or the inner surface 13 may have a curved shape in the cross-sectional view.

[0022] As shown in Figure 2, in the frame member 10, a weir portion 14 is integrally formed at the boundary between the inner surface 13 and the inner surface 23 of the cover plate 20, projecting inward from the inner surface 13 into the window W. The weir portion 14 is continuous along the inner surface 13 in the lateral direction (X1-X2 direction) and the vertical direction (Z1-Z2 direction), and is formed continuously around the entire circumference of the window W. The end face, which is part of the weir portion 14, is the weir end face 14a. The weir end face 14a is also continuous along the inner surface 13 in the lateral direction (X1-X2 direction) and the vertical direction (Z1-Z2 direction) at the boundary with the inner surface 23 of the cover plate 20, and is formed continuously around the entire circumference of the window W. The weir end face 14a is a plane parallel to the inner surface 13 and a plane perpendicular to the XZ plane, that is, a plane perpendicular to the inner surface 23 of the cover plate 20.

[0023] As shown in Figure 2, an adhesive layer 60a is formed on the inner surface 23 of the cover plate 20 that is visible in the window W surrounded by the frame member 10. The adhesive layer 60a is made of an optically clear adhesive. The optically clear adhesive (OCR), also called an optically elastic resin, is applied in liquid form to the inner surface of the cover plate 20 and cured, for example, by UV irradiation. The liquid optically clear adhesive applied to the inner surface 23 of the cover plate 20 is dammed at the dam end surface 14a and controlled so as not to overflow onto the inner surface 14b of the dam portion 14.

[0024] A shielding layer (decorative layer) 25 is formed on the inner surface of the peripheral portion of the cover plate 20. The shielding layer 25 is an opaque film, such as black or dark green. The shielding layer 25 is formed in a frame-like shape, covering the weir portion 14 and the weir end surface 14a from the outer peripheral edge 24 of the cover plate 20, and further covering a portion of the adhesive layer 60a.

[0025] A display cell 30 is fixed to the inner surface 23 of the cover plate 20, which is visible in the window W, via an adhesive layer 60a. The display cell 30 is a liquid crystal display cell, consisting of a front glass substrate 31 and a rear glass substrate 32 joined together, with a liquid crystal layer interposed between the two glass substrates 31 and 32. A transparent electrode is formed on the inner surface of the joint between the glass substrates 31 and 32, and a color filter is provided on the inner surface of one of the glass substrates. A polarizing layer 33 is superimposed on the front surface of the front glass substrate 31, and a polarizing layer 34 is superimposed on the rear surface of the rear glass substrate 32. The front surface of the front polarizing layer 33 is the front surface 30b of the display cell 30, and this front surface 30b is fixed to the inner surface 23 of the cover plate 20 via the adhesive layer 60a. Note that the display cell 30 is not limited to a liquid crystal display cell, but may also be an electroluminescent display cell or the like.

[0026] Next, the manufacturing method of the display device 1 will be described. Figure 3 shows the cover plate 20 before assembly. A protective sheet 40 is attached to the inner surface 23 of the cover plate 20. The protective sheet 40 is a release sheet, coated with a release agent such as fluorine on its surface, and is attached to the inner surface 23 of the cover plate 20 with relatively weak adhesive force. The protective sheet 40 is provided only in the central part of the inner surface 23 of the cover plate 20, and an area of ​​a certain width extending inward from the outer peripheral edge 24 of the cover plate 20 is an exposed area E where the protective sheet 40 is not present. Part of the shielding layer 25 is also exposed in the exposed area E. The exposed area E is continuous along the vertical direction (Z1-Z2 direction) and the horizontal direction (X1-X2 direction) on the inner surface 23 of the cover plate 20 and is formed with the same width dimension continuously around the entire circumference of the cover plate 20. The exposed area E is the outer peripheral part 21 of the cover plate 20.

[0027] Figures 4 and 5 show the process of molding the frame member 10 using the glass insert in-mold method. The molding die 50 has a lower die 51 and an upper die 52. As shown in Figure 4, the cover plate 20, with the protective sheet 40 attached, is held by air suction or the like on the inner surface 51a of the lower die 51. When the lower die 51 and the upper die 52 are joined together, the cover plate 20 and the protective sheet 40 are sandwiched between the inner surface 51a of the lower die 51 and the pressure surface 52a of the upper die 52, and the protective sheet 40 is pressed from the front-rear direction (Y1-Y2 direction) by the clamping pressure F. Inside the mold 50, a cavity 53 for molding the frame member 10 is formed on the outer periphery of the cover plate 20 and the protective sheet 40. The pressure surface 52a of the upper mold 52 is a plane parallel to the XZ plane, and a portion of the pressure surface 52a extends outward (towards the X2 side) beyond the protective sheet 40. As a result, a narrow cavity 53a for forming the weir 14 is formed as part of the cavity 53 in the gap between the extended pressure surface 52a and the inner surface 23 of the cover plate 20 (the surface of the shielding layer 25).

[0028] Within the mold 50, a thermoplastic elastomer, which is a synthetic resin material, is injected into the cavity 53 in a molten state while the cover plate 20 with the protective sheet 40 is held in place. The molten resin adheres to the outer edge 24 of the cover plate 20 and the inner surface 23 (shielding layer 25) of the cover plate 20 at the exposed portion E of the cover plate 20 that is exposed on the outer periphery side of the protective sheet 40. A portion of the molten resin flows into the narrow cavity 53a and adheres to the outer edge 41 of the protective sheet 40. After the resin in the cavity 53 hardens, the lower mold 51 and the upper mold 52 are separated, and the frame member 10 is molded in a state where it is fixed to the cover plate 20 by the hardened thermoplastic elastomer.

[0029] After removing the frame member 10, which is molded integrally with the cover plate 20, from the mold 50, the protective sheet 40 is peeled off from the inner surface 23 of the cover plate 20, forming a weir end surface 14a at the inner end of the weir section 14. As shown in Figure 4, the pressure surface 52a of the upper mold 52 is flat, and a narrow cavity 53a is formed in the portion of the pressure surface 52a that protrudes outward (towards X2) from the protective sheet 40. Therefore, a weir section 14 with a small thickness dimension h in the front-to-back direction (Y1-Y2 direction) can be molded with high precision without complicating the shape of the upper mold 52. In addition, since the weir end surface 14a is formed by the outer peripheral edge 41 of the protective sheet 40, a weir end surface 14a with a small height dimension h can be molded with high precision without generating burrs or other defects.

[0030] In the process shown in Figure 6, a liquid optical clear resin (OCR) 60 is applied to the inner surface 23 of the cover plate 20, which is visible in the window W surrounded by the frame member 10, using a dispenser or slit coating. The liquid optical clear resin 60 applied to the inner surface 23 of the cover plate 20 is dammed at the weir end surface 14a. Due to its viscosity and surface tension, the optical clear resin 60 in contact with the weir end surface 14a maintains a slightly raised liquid surface shape (i), as shown in Figure 7, thus making it easier to prevent the optical clear resin 60 from flowing out to the inner surface 14b of the weir 14.

[0031] In the process shown in Figure 7, the display cell 30 is bonded to the inner surface 23 of the cover plate 20 surrounded by the frame member 10. In a preferred bonding process, a liquid optical transparent adhesive 60 is applied to the inner surface of the cover plate 20, and then the optical transparent adhesive 60 is partially cured by UV irradiation to form an adhesive layer 60a. After that, the display cell 30 is bonded to the inner surface of the adhesive layer 60a, and the adhesive layer 60a is completely cured by UV irradiation. Alternatively, without a partial curing step, the optical transparent adhesive 60 may be applied to the inner surface of the cover plate 20, the display cell 30 may be bonded to the inner surface of the liquid optical transparent adhesive 60, the optical transparent adhesive 60 may be irradiated with UV light in the bonded state to cure the optical transparent adhesive 60 and form an adhesive layer 60a, and the cover plate 20 and the display cell 30 may be fixed by this adhesive layer 60a.

[0032] When the optical transparent adhesive 60 is applied to the inner surface 23 of the cover plate 20 and partially cured, the adhesive layer 60a maintains the raised shape (i) due to surface tension shown in Figure 7, so that the adhesive layer 60a does not overflow into the corner region (ii) between the inner surface 13 of the frame member 10 and the inner surface 14b of the weir 14. Furthermore, even when a process is adopted in which the display cell 30 is attached to the inner surface 23 of the cover plate 20 while the optical transparent adhesive 60 is still liquid and not partially cured, the optical transparent adhesive 60 is dammed by the weir end surface 14a and maintains a slightly raised liquid surface shape (i), so that the adhesive layer 60a does not flow out into the corner region (ii).

[0033] Since there is no adhesive layer 60a in region (ii), which is the corner between the inner surface 13 of the frame member 10 and the inner surface 14b of the weir portion 14, as shown in Figure 8, when the display cell 30 is attached to the inner surface 23 of the cover plate 20, the side end surface 30a of the display cell 30 and the inner surface 13 of the frame member 10 can be brought close together, and the area enclosed by the frame member 10 can be widely and effectively used for display. In addition, the thickness dimension h in the front-to-back direction (Y1-Y2 direction) of the weir portion 14, which is integrated with the frame member 10, is extremely small, matching the thickness of the protective sheet 40, for example, h is about 0.5 mm or more and 1.5 mm or less. Therefore, the front surface 30b of the display cell 30 facing the cover plate 20, which is attached with the adhesive layer 60a in between, can be positioned behind the weir end surface 14a (Y2 direction), and a small gap δ can be formed between the front surface 30b of the display cell 30 and the inner surface 14b of the weir portion 14. This also allows the side end surface 30a of the display cell 30 to be brought closer to the inner surface 13 of the frame member 10. [Explanation of Symbols]

[0034] 1 Display device 10 Frame members 13 Inner surface 14 Weir 14a Weir end face 20 Cover boards 21 Outer periphery 22 Exterior 23 Inner self 30 Display Cells 30a Side end surface 30b front 40 protective sheets 41 Outer edge 50 molds 51 Lower mold 52 Upper mold

Claims

1. A display device comprising a frame member, a glass cover plate fixed to the frame member, an adhesive layer formed on the inner surface of the cover plate that is visible in the window enclosed by the frame member, and a display cell fixed to the inner surface via the adhesive layer, The frame member has an inner surface surrounding the window, a weir portion projecting from the inner surface toward the window, and a weir end surface that is part of the weir portion and is continuous around the entire circumference of the window at the boundary with the inner surface of the cover plate. The display device is characterized in that the adhesive layer is formed by an optically transparent adhesive applied to the inner surface of the cover plate and in contact with the weir end surface.

2. The display device according to claim 1, wherein the frame member is formed in close contact with the cover plate using a synthetic resin material.

3. The display device according to claim 1 or 2, wherein the front surface of the display cell facing the cover plate is located rearward from the weir end surface in a direction away from the cover plate.

4. The display device according to claim 1 or 2, wherein the adhesive layer is not present between the side end face of the display cell and the inner surface of the frame member.

5. A method for manufacturing a display device comprising a frame member, a glass cover plate fixed to the frame member, an adhesive layer formed on the inner surface of the cover plate that is visible in a window surrounded by the frame member, and a display cell fixed to the inner surface via the adhesive layer, The process involves using a glass insert in-mold method to mold the frame member to the cover plate using a synthetic resin material, In the above step, the frame member is formed with an inner surface surrounding the window, a weir portion projecting from the inner surface toward the inside of the window, and a weir end surface which is a part of the weir portion and is continuous around the entire circumference of the window at the boundary with the inner surface of the cover plate. A method for manufacturing a display device, characterized by damming a liquid optical transparent adhesive applied to the inner surface of the cover plate at the dam end surface, and curing the optical transparent adhesive to form the adhesive layer.

6. In the glass insert in-molding method described above, with a protective sheet attached to the inner surface of the cover plate, the frame member is formed in close contact with the outer edge of the protective sheet and the outer edge of the cover plate that is exposed on the outer side of the protective sheet. A method for manufacturing a display device according to claim 5, wherein the protective sheet is peeled off from the inner surface of the cover plate to form the weir end surface.

7. A method for manufacturing a display device according to claim 5 or 6, wherein the front surface of the display cell facing the cover plate is positioned rearward, away from the cover plate than the weir end surface, and the display cell is fixed to the inner surface of the cover plate.

8. A method for manufacturing a display device according to claim 5 or 6, wherein when the display cell is fixed to the inner surface of the cover plate, the adhesive layer is not present between the side end surface of the display cell and the inner surface of the frame member.

Images