Display device and manufacturing method thereof

Abstract

To reduce material required for sticking of a display panel and a protective panel, and also suppress entrainment of air.SOLUTION: A display device 100 comprises a display panel 1 which displays information, and a protective panel 3 which is made of resin having a light transmission property and laminated on a display surface 1a side of the display panel 1, and the protective panel 3 is stuck on the display surface 1a of the display panel 1 via a light-permeable adhesive 8. The light-permeable adhesive 8 has viscosity in which coating thickness can be kept even after applied to a coating region of the protective panel 3 or the display panel 1. Regarding the coating thickness of the light-permeable adhesive 8 in the coating region, the center-side thickness is larger than the thickness of an end part of the coating region.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a display device and a manufacturing method thereof. [Background technology]

[0002] BACKGROUND ART Display devices that employ optical bonding, in which a translucent protective panel is bonded to the display surface of a display panel via a translucent adhesive, are known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-94905 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned display device, a dam material may be applied around the area where the translucent adhesive is applied to prevent the adhesive from spilling out. In this case, at least two types of coating materials are required to bond the display panel and the protection panel.

[0005] In recent years, it has been proposed to make protective panels out of resins such as acrylic (PMMA), but if the resin protective panel is deformed or warped, the translucent adhesive will not be able to follow the deformation or warping of the protective panel, which could result in air being trapped inside.

[0006] Therefore, an object of the present disclosure is to provide a display device that not only reduces the amount of material required to bond the display panel and the protective panel but also suppresses air entrapment, and a manufacturing method thereof. [Means for solving the problem]

[0007] In one aspect, the following solution is provided. a display panel for displaying information; a protective panel made of a translucent resin and laminated on the display surface side of the display panel; A display device in which the protective panel is bonded to a display surface of the display panel via a light-transmitting adhesive, the translucent adhesive has a viscosity that allows the adhesive to maintain a coating thickness even after being applied to the application area of ​​the protective panel or the display panel; The thickness of the applied light-transmitting adhesive in the applied region is greater at the center than at the edges of the applied region. [Effects of the Invention]

[0008] According to the present disclosure, not only can the amount of material required to bond the display panel and the protection panel be reduced, but air entrapment can also be suppressed. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic front view of a display device according to an embodiment of the present disclosure. [Figure 2] 2 is a schematic cross-sectional view taken along the line AA in FIG. 1. [Figure 3] FIG. 2 is an enlarged cross-sectional view of a main part indicated by AA in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, the embodiments will be described in detail with reference to the accompanying drawings.

[0011] (Display device configuration) A display device 100 according to an embodiment of the present disclosure will be described with reference to Figures 1 to 3. The display device 100 is mounted on a vehicle (such as an automobile, motorcycle, agricultural machinery, or construction machinery) and configured as an instrument device that displays information such as vehicle speed.

[0012] In the following, to make it easier to understand the configuration of the display device 100, the direction in which the user seated in the driver's seat of the vehicle is viewed from the display device 100 will be referred to as the "front" and the opposite side as the "rear" for each component.

[0013] The display device 100 includes a display panel 1, a resin bezel 2, a protective panel 3, a frame 4, a circuit board 5, and a lower case member 6.

[0014] The display panel 1 is a display that displays various types of vehicle information, and is configured, for example, with a TFT color liquid crystal module. The display state (display content) of the display panel 1 is controlled by a control unit (vehicle ECU, etc.) not shown. The various types of vehicle information displayed by the display panel 1 include, for example, vehicle speed, engine RPM, cumulative mileage, remaining cruising distance, average fuel economy, and the status of other surrounding vehicles.

[0015] The display panel 1 has a display surface 1a on the front side visible to the user, and a backlight (not shown) on the rear side behind the display surface 1a. The backlight has light emitters such as light-emitting diodes and optical sheets such as a diffusion plate, and illuminates the display panel 1 evenly from the rear side.

[0016] The resin bezel 2 integrally comprises a bottom surface 2a that covers the back side of the display panel 1 and a side wall portion 2b that rises from the outer periphery of the bottom surface 2a and surrounds the outer periphery of the display panel 1. The display panel 1 is housed in the resin bezel 2 beforehand and supplied as a display unit. However, the display panel 1 and the resin bezel 2 are not integrated, and there is a possibility that the display panel 1 and the resin bezel 2 will vibrate separately when subjected to vibration. Furthermore, a tip surface 2c of the side wall portion 2b of the resin bezel 2 is substantially flush with the display surface 1a of the display panel 1, but a concave gap S exists between the tip surface 2c and the display surface 1a.

[0017] The protective panel 3 is a plate member made of a translucent (including transparent and translucent) resin such as acrylic resin, and is laminated on the display surface 1a side of the display panel 1. The protective panel 3 includes a translucent region 3a that allows the display surface 1a (effective display area) of the display panel 1 to be visible to the user, and a light-shielding region 3b that prevents the user from viewing the outer periphery of the display surface 1a (effective display area). The light-shielding region 3b is formed by a light-shielding printed layer (not shown) applied to the back surface of the outer periphery of the display panel 1.

[0018] The protective panel 3 may be deformed or warped due to the influence of heat received during the formation of the panel itself or during insert molding with the frame 4. Furthermore, the protective panel 3 may not be flat for design reasons, but may include curved or tapered surfaces. For example, as shown in Figures 2 and 3, the protective panel 3 of this embodiment has a shape in which the center bulges forward more than both ends in the longitudinal direction (lateral direction) of the protective panel 3.

[0019] The display surface 1a of the display panel 1 and the protection panel 3 are bonded together by optical bonding, which will be described later.

[0020] The frame 4 is a light-blocking resin member having a frame shape that integrally supports the outer periphery of the protective panel 3, and is integrated with the protective panel 3 by, for example, insert molding. The frame 4 has a side wall 4a that surrounds the outer periphery of the display panel 1 and the resin bezel 2.

[0021] The circuit board 5 is made of, for example, a rigid wiring board in which a wiring pattern (not shown) is applied to a flat glass epoxy base material, and is disposed on the rear side of the display panel 1. Various circuit components (not shown) are mounted on the circuit board 5, and the drive circuit of the display panel 1 is configured by these circuit components and the wiring pattern.

[0022] The lower case member 6 is a light-blocking resin member that covers the opening on the rear side of the frame body 4, thereby closing off the storage space for the display panel 1, the resin bezel 2, and the circuit board 5. The lower case member 6 is fixed to the frame body 4 using a plurality of screws 7, but the means for fixing the lower case member 6 to the frame body 4 is not limited to screw fixing.

[0023] (Optical Bonding) The optical bonding for bonding the display surface 1a of the display panel 1 and the protection panel 3 together will now be described.

[0024] For optical bonding, a translucent adhesive 8 made of OCR (Optical Clear Resin) material is used. The translucent adhesive 8 used is a UV delayed curing type that begins to harden when triggered by UV (ultraviolet) irradiation, and has a viscosity that allows the coating thickness to be maintained even after application. Specifically, a viscosity of 45,000 cp or more is preferable.

[0025] Optical bonding using such a translucent adhesive 8 can prevent the translucent adhesive 8 from overflowing without using a dam material, which not only reduces the amount of material required to bond the display panel 1 and the protective panel 3, but also simplifies the manufacturing process.

[0026] The optical bonding process includes a coating process, a UV irradiation process, and a bonding process.

[0027] In the application step, the protective panel 3 integrated with the frame 4 by insert molding is fixed with its back surface facing upward, and then a dispenser (not shown) is used to apply the translucent adhesive 8 to the back surface of the protective panel 3. The application area of ​​the translucent adhesive 8 on the back surface of the protective panel 3 corresponds to a planar shape including the display surface 1a of the display panel 1 and the tip surface 2c of the resin bezel 2 arranged on the outer periphery thereof.

[0028] The thickness of the light-transmitting adhesive 8 applied in the application area is set to be thicker at the center than at the edges of the application area. For example, when applying the light-transmitting adhesive 8 while scanning a dispenser with a constant discharge amount along the back surface of the protective panel 3, the scanning speed can be slower at the center of the application area than at the edges, so that the thickness of the light-transmitting adhesive 8 applied is thinner at the edges of the application area and thicker at the center.

[0029] In the UV irradiation process, a UV irradiation device (not shown) is used to irradiate the light-transmitting adhesive 8 with UV in order to initiate hardening of the applied light-transmitting adhesive 8. At this time, UV irradiation is performed so that the light-transmitting adhesive 8 at the edges of the applied area hardens faster than the light-transmitting adhesive 8 at the center. For example, when UV is irradiated onto the light-transmitting adhesive 8 while a UV irradiation unit with a constant amount of UV irradiation is scanned along the back surface of the protective panel 3, the hardening speed of the light-transmitting adhesive 8 can be made faster at the edges of the applied area and slower at the center by making the scanning speed faster at the center than at the edges.

[0030] In the above example, the curing speed of the translucent adhesive 8 is changed based on the amount of UV irradiation, but the curing speed of the translucent adhesive 8 may also be changed based on the timing of UV irradiation. For example, UV may first be irradiated onto the edge of the application area, and then UV may be irradiated onto the center of the application area after a predetermined time.

[0031] In the bonding process, the display surface 1a of the display panel 1 is bonded to the back side of the protective panel 3, on which the light-transmitting adhesive 8 has been applied, using a bonding jig in a vacuum environment or an atmospheric environment. At this time, the thickness of the light-transmitting adhesive 8 applied in the application area is thicker in the center than at the edges of the application area, so the light-transmitting adhesive 8 in the center of the application area can easily adapt to deformation and warping of the protective panel 3. This makes it possible to bond the display panel 1 to the protective panel 3 while suppressing air entrapment.

[0032] Furthermore, the translucent adhesive 8 at the edges of the application area is irradiated with UV light so that it hardens faster than the translucent adhesive 8 at the center, thereby preventing misalignment after bonding. Furthermore, since the hardening of the translucent adhesive 8 at the center can be delayed compared to the translucent adhesive 8 at the edges of the application area, the ability to follow deformation and warping of the protective panel 3 can be further improved.

[0033] Furthermore, during the bonding process, the pressure applied during bonding causes the translucent adhesive 8 to fill the gap S between the display panel 1 and the resin bezel 2, thereby improving the integrity and vibration resistance of the display panel 1 and the resin bezel 2.

[0034] Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and variations are possible within the scope of the claims. It is also possible to combine all or a plurality of the components of the above-described embodiments. For example, in the above-described embodiment, the translucent adhesive is applied to the protection panel side, but the translucent adhesive may be applied to the display panel side. [Explanation of symbols]

[0035] 100 display device 1 Display panel 1a Display surface 2 Resin bezel 2a Bottom part 2b Side wall part 2c Tip surface 3 Protective Panel 3a Translucent area 3b Shading area 4 Frame 4a Side wall part 5 Circuit Board 6 Lower case member 7 bis 8. Translucent adhesive S Gap

Claims

1. a display panel for displaying information; a protective panel made of a translucent resin and laminated on the display surface side of the display panel; A display device in which the protective panel is bonded to a display surface of the display panel via a light-transmitting adhesive, the translucent adhesive has a viscosity that allows the adhesive to maintain a coating thickness even after being applied to the application area of ​​the protective panel or the display panel; A display device, wherein the thickness of the applied light-transmitting adhesive in the applied region is greater at the center than at the ends of the applied region.

2. The display device according to claim 1 , wherein the viscosity of the transparent adhesive is 45,000 cp or more.

3. Further, a resin bezel is provided to surround the outer periphery of the display panel. The display device according to claim 1 , wherein the transparent adhesive is also filled in a gap between the display panel and the resin bezel.

4. the transparent adhesive is a UV delayed curing adhesive, The display device according to claim 1 , wherein the light-transmitting adhesive at the edge of the application region is hardened faster than the light-transmitting adhesive at the center.

5. a display panel for displaying information; a protective panel made of a translucent resin and laminated on the display surface side of the display panel; A method for manufacturing a display device, comprising bonding the protective panel to a display surface of the display panel via a light-transmitting adhesive, applying the transparent adhesive to an application area of ​​the protective panel or the display panel; and attaching the protective panel to the display surface of the display panel via the light-transmitting adhesive, the translucent adhesive has a viscosity that allows the adhesive to maintain a coating thickness even after being applied to the application area of ​​the protective panel or the display panel; A method for manufacturing a display device, wherein the thickness of the applied light-transmitting adhesive in the applied region is greater at the center than at the edges of the applied region.

6. The method for manufacturing a display device according to claim 5 , wherein the viscosity of the light-transmitting adhesive is 45,000 cp or more.

7. the display device further includes a resin bezel surrounding an outer periphery of the display panel; The method for manufacturing a display device according to claim 5 , wherein the transparent adhesive is also filled in a gap between the display panel and the resin bezel.

8. the transparent adhesive is a UV delayed curing adhesive, The method for manufacturing a display device according to claim 5 , wherein the light-transmitting adhesive at the edge of the application region is cured faster than the light-transmitting adhesive at the center.

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