Production method for display unit

Abstract

A production method for a display unit according to the present invention involves applying a liquid curable resin composition to a principal surface of a glass cover that includes a glass plate that has a curved surface part in a state in which the principal surface of the glass cover has been leveled to be flat and forming a curable resin composition layer, at least partially curing the curable resin composition layer in a state in which the principal surface of the glass cover has been leveled to be flat, and adhering the glass cover and a display with an adhesive layer formed by curing the curable resin composition therebetween.

Description

Display unit manufacturing method

[0001] The present disclosure relates to a method for manufacturing a display unit.

[0002] Patent Document 1 describes a method of bonding a curved glass cover and a flat display panel with an ultraviolet curable resin, and illustrates that the ultraviolet curable resin is applied to the curved surface of the glass cover.

[0003] Chinese Patent Application Publication No. 105242430

[0004] If the viscosity of the curable resin composition is too low, the curable resin composition applied to the curved surface of the glass cover will flow out over time due to gravity, causing dripping. On the other hand, if the viscosity of the curable resin composition is too high, it will not be possible to apply it to the curved surface of the glass cover. Therefore, it is difficult to form an adhesive layer of uniform thickness. If the thickness of the adhesive layer is uneven, poor adhesion may occur. Poor adhesion may include at least one of perspective distortion, air bubble entrapment, and wrinkles in the adhesive layer due to uneven stress in the adhesive layer.

[0005] One aspect of the present disclosure provides a technology that can form an adhesive layer of uniform thickness on the curved surface of a glass cover and suppress the occurrence of poor adhesion.

[0006] A method for manufacturing a display unit according to one embodiment of the present disclosure includes: applying a liquid curable resin composition to a main surface of a glass cover, the main surface of which includes a glass plate having a curved portion, while the main surface of the glass cover is corrected to be flat, to form a curable resin composition layer; at least partially curing the curable resin composition layer while the main surface of the glass cover is corrected to be flat; and adhering the glass cover and a display together via an adhesive layer formed by curing the curable resin composition.

[0007] According to one aspect of the present disclosure, an adhesive layer of uniform thickness can be formed on the curved surface of the glass cover, thereby suppressing the occurrence of poor adhesion.

[0008] FIG. 1 is a diagram showing an example of installation of a display unit according to an embodiment. FIG. 2 is a cross-sectional view showing an example of the configuration of a display unit. FIG. 3 is a flowchart showing a method for manufacturing a display unit according to an embodiment. FIG. 4 is a cross-sectional view showing an example of S101. FIG. 5 is a cross-sectional view showing an example of S102. FIG. 6 is a cross-sectional view showing an example of S103. FIG. 7 is a cross-sectional view showing an example of S104. FIG. 8 is a cross-sectional view showing an example of S105. FIG. 9 is a cross-sectional view showing an example of S106. FIG. 10 is a cross-sectional view showing an example of S107. FIG. 11 is a cross-sectional view showing an example of S108. FIG. 12 is a cross-sectional view showing an example of a second S106. FIG. 13 is a cross-sectional view showing an example of a second S107. FIG. 14 is a cross-sectional view showing an example of a second S108. FIG. 15 is a cross-sectional view showing an example of a display unit obtained after S110. FIG. 16 is a flowchart showing a method for manufacturing a display unit according to a first modified example. FIG. 17 is a flowchart showing a method for manufacturing a display unit according to a second modified example.

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In each drawing, the same or corresponding components are denoted by the same reference numerals, and their description may be omitted. In the specification, the symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. The range of values ​​includes the range rounded up or down.

[0010] 1, the display unit 10 is mounted on, for example, a vehicle 1, and is preferably provided in front of the driver of the vehicle 1, and displays, for example, an image that assists in driving the vehicle 1. The configuration and installation position of the display unit 10 are arbitrary. The use of the display unit 10 is also arbitrary and is not limited to vehicle use.

[0011] 2, the display unit 10 includes at least a glass cover 20, a display 30, and an adhesive layer 40. The adhesive layer 40 bonds the glass cover 20 and the display 30 together. A user views an image on the display 30 through the glass cover 20 and the adhesive layer 40. The user is, for example, a passenger in the vehicle 1. The passenger is at least one of the driver and a passenger.

[0012] The display unit 10 may further include a housing 50 and a cover 60. The housing 50 houses the display 30 and is attached to the glass cover 20. In this embodiment, the curved surface formed by the glass cover 20 and the display 30 is concave toward the user, but may also be convex. The display 30 may include a touch sensor (not shown). The cover 60 covers the housing 50. Although not shown, the display unit 10 may include a member that serves as both the housing 50 and the cover 60.

[0013] The glass cover 20 is a transparent plate-like member that transmits visible light. When the glass cover 20 is removed from the housing 50 and no external force is acting on the glass cover 20, that is, when the glass cover 20 is not elastically deformed, the glass cover 20 has a curved shape. Note that the glass cover 20 may be further elastically deformed to increase the curvature before being attached to the housing 50.

[0014] When the glass cover 20 is removed from the housing 50 and no external force is acting on the glass cover 20, that is, when the glass cover 20 is not elastically deformed, at least a portion of the glass cover 20 may have the following radius of curvature: The radius of curvature is preferably 50 mm or more and 10,000 mm or less, more preferably 100 mm or more and 8,000 mm or less, and even more preferably 300 mm or more and 6,000 mm or less.

[0015] The glass cover 20 has a first main surface 20a and a second main surface 20b facing opposite to the first main surface 20a. The second main surface 20b is in contact with the adhesive layer 40. The first main surface 20a and the second main surface 20b may or may not be a single curved surface. The first main surface 20a and the second main surface 20b may have at least a partially curved surface, or may have a partially flat surface.

[0016] The thickness of the glass cover 20 is preferably 0.3 mm or more and 2.5 mm or less. The thickness of the glass cover 20 is preferably 0.3 mm or more, more preferably 0.4 mm or more, and even more preferably 0.6 mm or more. The thickness of the glass cover 20 is preferably 2.5 mm or less, more preferably 2.0 mm or less, and even more preferably 1.3 mm or less. By setting the lower limit of the thickness to the above value, the rigidity of the glass cover 20 can be ensured and cracking of the glass cover 20 can be suppressed. By setting the upper limit of the thickness to the above value, peeling of the glass cover 20 from the housing 50 can be suppressed.

[0017] When glass cover 20 is removed from housing 50 and no external force is acting on glass cover 20, that is, when glass cover 20 is not elastically deformed, it is preferable that the radius of curvature of the curved surface of glass cover 20 is 300 mm or more and 4000 mm or less and the thickness is 0.3 mm or more and 2.0 mm or less. Having the radius of curvature and thickness of glass cover 20 within the above ranges can prevent cracking of glass cover 20 when correcting glass cover 20 to a flat surface, as described below.

[0018] The glass cover 20 is, for example, rectangular when viewed from a user facing the first main surface 20a. The length of the long side of the rectangle is preferably 100 mm or more and 1600 mm or less. The length of the short side of the rectangle is preferably 40 mm or more and 800 mm or less. However, the glass cover 20 is not limited to a rectangular shape when viewed from a user facing the first main surface 20a, and may be any shape, such as an ellipse.

[0019] The Young's modulus of the glass cover 20 is preferably 60 GPa or more, and more preferably 70 GPa or more. The Young's modulus of the glass cover 20 is preferably 90 GPa or less, more preferably 80 GPa or less, and even more preferably 75 GPa or less. The Young's modulus of the glass cover 20 is preferably 60 GPa or more and 90 GPa or less, more preferably 70 GPa or more and 80 GPa or less, and even more preferably 70 GPa or more and 75 GPa or less. Having the Young's modulus within this range can suppress cracking.

[0020] The glass cover 20 includes a glass plate 21. The glass plate 21 has a curved surface portion. The glass plate 21 has the curved surface portion when no external force is applied, i.e., when not elastically deformed. The glass plate 21 is preferably hot-bent. Hot-bending is a process in which the glass plate 21 is plastically deformed while being heated to a temperature equal to or higher than the glass transition point. The glass plate 21 may be further elastically deformed to increase its curvature before being attached to the housing 50.

[0021] The glass plate 21 is preferably tempered glass, and the tempered glass is preferably chemically tempered glass. The tempered glass has a compressive stress layer on its surface. The compressive stress layer of chemically tempered glass is formed by exchanging alkali metal ions (e.g., Na ions) contained in the glass with alkali metal ions (e.g., K ions) having a larger ionic radius at a temperature below the glass transition point. The ion exchange is generally performed after hot bending.

[0022] When the glass plate 21 is chemically strengthened glass, the thickness (DOL) of the compressive stress layer of the glass plate 21 is preferably 5 μm or more, more preferably 10 μm or more, even more preferably 20 μm or more, and even more preferably 30 μm or more. Furthermore, the DOL is preferably 100 μm or less, and more preferably 40 μm or less. It is preferable that at least one of the first main surface 21a and the second main surface 21b of the glass plate 21 has a DOL in the above range, and more preferably both have a DOL in the above range. By setting the DOL in the above range, cracking can be suppressed.

[0023] When the glass plate 21 is chemically strengthened glass, the surface compressive stress (CS) in the compressive stress layer is preferably 500 MPa or more, more preferably 650 MPa or more, even more preferably 750 MPa or more, and particularly preferably 900 MPa or more. While there is no particular upper limit, for example, CS is preferably 1200 MPa or less. It is preferable that at least one of the first main surface 21a and the second main surface 21b of the glass plate 21 has CS in the above range, and more preferably both have CS in the above range. Having CS in the above range can suppress cracking.

[0024] When the glass plate 21 is chemically strengthened glass, the internal tensile stress CT of the glass plate 21 is preferably 1 MPa or more, more preferably 2 MPa or more and 100 MPa or less, even more preferably 5 MPa or more and 70 MPa or less, and even more preferably 8 MPa or more and 50 MPa or less. When CT is in the above range, cracking can be suppressed.

[0025] The glass constituting the glass plate 21 is not particularly limited, but may be, for example, soda lime glass or aluminosilicate glass (SiO ２ -Al ２ O ３ -Na ２ O-based glass). From the viewpoint of strength, aluminosilicate glass is preferred. Chemically strengthened glass based on aluminosilicate glass is also preferably used, for example, "Dragon Trail (registered trademark)" manufactured by AGC.

[0026] The glass constituting the glass plate 21 has, for example, SiO 2 in mole % on an oxide basis. ２ 50% or more and 80% or less, Al ２ O ３ 1% or more and 20% or less, Na ２ O is 6% or more and 20% or less, K is ２ O is 0% or more and 11% or less, MgO is 0% or more and 15% or less, CaO is 0% or more and 6% or less, and ZrO ２ For example, "containing 0% to 15% of MgO" means that MgO is not essential but may be contained up to 15%.

[0027] Examples of the glass constituting the glass plate 21 include the following glass compositions (i) to (vi). The glass (i) below is included in soda lime silicate glass. The glasses (ii) to (iii) below are included in aluminosilicate glass. The glasses (iv) to (vi) below are included in lithium aluminosilicate glass.

[0028] (i) In mole percent on an oxide basis, SiO ２ 63% to 73%, Al ２ O ３ 0.1% to 5.2%, Na ２ O 10% to 16%, K ２ O from 0% to 1.5%, Li ２ A glass containing 0% to 5.0% of O, 5% to 18% of MgO, and 1% to 10% of CaO.

[0029] (ii) In mole percent on an oxide basis, SiO ２ 50% to 74%, Al ２ O ３ 5% to 15%, Na ２ O 10% to 20%, K ２ O from 0% to 8%, Li ２ O 0% to 5.0%, MgO 2% to 15%, CaO 0% to 6% and ZrO ２ Contains 0% to 5% of SiO ２ and Al ２ O ３ The total content of 65% to 85%, Na ２ O and K ２ A glass having a total O content of 12% to 25%, and a total MgO and CaO content of 1% to 15%.

[0030] (iii) In mole percent on an oxide basis, SiO ２ 68% to 80%, Al ２ O ３ 4% to 10%, Na ２ O 5% to 15%, K ２ O from 0% to 1%, Li ２ O 0% to 5.0%, MgO 4% to 15% and ZrO ２ Glass containing 0% to 1% of

[0031] (iv) In mole percent on an oxide basis, SiO ２ 67% to 75%, Al ２ O ３ 0% to 4%, Na ２ O 7% to 15%, K ２ 1% to 9% O, Li ２ O 0% to 5.0%, MgO 6% to 14% and ZrO ２ Contains 0% to 1.5% of SiO ２ and Al ２ O ３ The total content of 71% to 75%, Na ２ O and K ２ A glass having a total O content of 12% to 20%, and if CaO is contained, the content thereof is less than 1%.

[0032] (v) In mole percent on an oxide basis, SiO ２ 50% to 73%, Al ２ O ３ 5% to 20%, B ２ O ３ 0% to 6%, P ２ O ５ 0% to 10%, Li ２ 4% to 12% O, Na ２ O 3% to 20%, K ２ O 0% to 5%, MgO 0% to 8%, CaO 0% to 2%, SrO 0% to 5%, BaO 0% to 5%, ZnO 0% to 5%, TiO ２ 0% to 2%, ZrO ２ Glass containing 0% to 4% of

[0033] (vi) In mole percent on an oxide basis, SiO ２ 58% to 80%, Al ２ O ３ 13% to 18%, B ２ O ３ 0% to 5%, P ２ O ５ 0.5% to 4%, Li ２ 3% to 10% O, Na ２ O 5% to 20%, K ２ O 0% to 2%, MgO 0% to 11%, CaO 0% to 20%, SrO 0% to 20%, BaO 0% to 15%, ZnO 0% to 10%, TiO２ 0% to 1%, ZrO ２ Glass containing 0% to 2% of

[0034] The thickness of the glass plate 21 is preferably 0.2 mm to 2.0 mm, more preferably 0.3 mm to 1.8 mm, and even more preferably 0.5 mm to 1.5 mm. By setting the thickness of the glass plate 21 within the above range, it is possible to achieve both a lightweight glass plate 21 and high strength.

[0035] The glass cover 20 may include, in addition to the glass plate 21, at least one of an AG layer 22, an AR layer 23, an AFP layer 24, and a printed layer 25. The AG layer 22, the AR layer 23, and the AFP layer 24 are formed in this order on the first main surface 21a of the glass plate 21. The printed layer 25 is formed on the second main surface 21b of the glass plate 21. The AG layer 22, the AR layer 23, the AFP layer 24, and the printed layer 25 each have a curved shape that conforms to the glass plate 21.

[0036] The glass cover 20 may also include a touch sensor (not shown) in addition to the glass plate 21. The touch sensor is disposed on the second main surface 21b side of the glass plate 21.

[0037] The AG (Anti-Glare) layer 22 is an anti-glare layer that imparts anti-glare properties to the glass cover 20. The AG layer 22 preferably has an uneven surface. The surface roughness (root mean square roughness, RMS) of this uneven surface is preferably 25 nm to 1000 nm, more preferably 10 nm to 500 nm. The AG layer 22 may be formed by etching the glass plate 21, or may be formed separately from the glass plate 21. In the latter case, the AG layer 22 may be a coating film containing a plurality of particles dispersed therein, or may be a transparent resin film having a textured pattern transferred onto its surface. The coating film may be a transparent resin film containing a plurality of particles dispersed therein.

[0038] The AR (Anti-Reflection) layer 23 is an anti-reflection layer that reduces glare caused by reflected light. The AR layer 23 improves the visibility of images on the display 30. The AR layer 23 is configured by alternately laminating high-refractive index layers with a refractive index of 1.9 or more at a wavelength of 550 nm and low-refractive index layers with a refractive index of 1.6 or less at a wavelength of 550 nm, for example. In this embodiment, the AR layer 23 is provided on the AG layer 22, but the AG layer 22 may be omitted, and the AR layer 23 may be provided directly on the glass plate 21. The AR layer 23 may also be omitted.

[0039] The AFP (Anti-Fingerprint) layer 24 is an anti-fouling layer that prevents the adhesion of dirt. The dirt may be, for example, at least one of fingerprints, sweat, and dust. Due to its characteristics, the AFP layer 24 is preferably formed on the outermost surface of the glass cover 20. The AFP layer 24 is preferably made of a fluorine-containing organic compound (a compound having a fluorine-containing organic group) that can impart dirt resistance, water repellency, and oil repellency. Examples of fluorine-containing organic compounds include fluorine-containing organosilicon compounds.

[0040] The printed layer 25 is provided along at least a portion (preferably the entirety) of the periphery of the glass plate 21. The printed layer 25 conceals, for example, the wiring of the display 30, thereby improving the design of the display 30. The color of the printed layer 25 is, for example, black, but is not limited to black as long as it has high light-blocking properties, and may be a wood grain pattern or the like.

[0041] The display 30 displays an image. When the display 30 is removed from the housing 50 and no external force is acting on the display 30, that is, when the display 30 is not elastically deformed, the display 30 has a flat shape. The display 30 is attached to the housing 50 after being elastically deformed to have a curved shape. Note that, like the glass cover 20, the display 30 may have a curved shape when not elastically deformed.

[0042] The display 30 has a first main surface 30a that displays an image toward the user and a second main surface 30b facing opposite to the first main surface 30a. The first main surface 30a is in contact with the adhesive layer 40. The first main surface 30a and the second main surface 30b may or may not be single curved surfaces. The first main surface 30a and the second main surface 30b may have at least a partially curved surface, or may have a partially flat surface.

[0043] The display 30 is a liquid crystal display, an organic electroluminescence (EL) display, a micro LED display, or the like. The display 30 may have a touch sensor that detects the approach of an object (e.g., a finger or a pen). In this embodiment, the display 30 has a liquid crystal panel 31 and a backlight unit 32 that is provided on the opposite side of the glass cover 20 from the liquid crystal panel 31.

[0044] The Young's modulus of the liquid crystal panel 31 is preferably 2 GPa or more, more preferably 60 GPa or more, and even more preferably 70 GPa or more. The Young's modulus of the liquid crystal panel 31 is preferably 90 GPa or less, and more preferably 75 GPa or less. The Young's modulus of the liquid crystal panel 31 is preferably 20 GPa to 90 GPa, more preferably 60 GPa to 75 GPa, and even more preferably 70 GPa to 75 GPa.

[0045] The thickness of the liquid crystal panel 31 is preferably 0.05 mm or more, more preferably 1.0 mm or more, and even more preferably 1.1 mm or more. The thickness of the liquid crystal panel 31 is preferably 2.0 mm or less, and more preferably 1.3 mm or less. The thickness of the liquid crystal panel 31 is preferably 0.05 mm or more and 2.0 mm or less, more preferably 1.0 mm or more and 1.3 mm or less, and even more preferably 1.1 mm or more and 1.3 mm or less.

[0046] The backlight unit 32 is generally composed of a lens sheet, a diffusion sheet, a light guide plate, LEDs, a reflector, etc. The Young's modulus of the backlight unit 32 is preferably 1 GPa or more and 5 GPa or less, and more preferably 2 GPa or more and 5 GPa or less.

[0047] The thickness of the backlight unit 32 is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 3 mm or more. The thickness of the backlight unit 32 is preferably 10 mm or less, more preferably 6 mm or less, and even more preferably 5 mm or less. The thickness of the backlight unit 32 is preferably 1 mm or more and 10 mm or less, more preferably 2 mm or more and 6 mm or less, and even more preferably 3 mm or more and 5 mm or less.

[0048] The adhesive layer 40 is a layer formed by curing a curable resin composition layer 40A (see FIG. 5 ) formed by applying a curable resin composition. Examples of the curable resin composition include a thermosetting resin composition and a photocurable resin composition. The adhesive layer 40 is preferably a transparent layer that transmits visible light. Furthermore, the curable resin composition is preferably a photocurable resin composition because it can be cured at low temperatures. The photocurable resin composition contains a photocurable compound (A) having a curable group. The photocurable compound (A) contains, for example, at least one of an acrylic-based compound, a silicone-based compound, a urethane acrylate-based compound, and an epoxy-based compound.

[0049] The photocurable resin composition preferably further contains a photopolymerization initiator (B) from the viewpoint of being able to cure quickly at low temperatures. The photocurable resin composition may contain a non-curable component other than the photopolymerization initiator (B). The non-curable component includes at least one of a non-curable polymer (C), a chain transfer agent (D), and other additives (catalyst, curing rate adjuster), etc.

[0050] The photocurable resin composition may also be a delayed-curing photocurable resin composition. Here, delayed curing refers to the property that, after irradiating the photocurable resin composition with light, the time until the curing reaction of the photocurable resin composition is completely completed is longer than the light irradiation time. If the photocurable resin composition is a delayed-curing photocurable resin composition, the degree of freedom in process design from irradiating the curable resin composition layer 40A with light to bonding the glass cover 20 and the display 30 increases, which can be useful for improving the efficiency and precision of the bonding process.

[0051] The viscosity of the photocurable resin composition before the start of curing is preferably 0.05 Pa·s to 50 Pa·s, and more preferably 1 Pa·s to 20 Pa·s. If the viscosity is 0.05 Pa·s or more, the application efficiency of the photocurable resin composition can be improved. Furthermore, if the viscosity is 50 Pa·s or less, voids are less likely to remain.

[0052] The thickness of the adhesive layer 40 is preferably 0.05 mm or more. By making the thickness of the adhesive layer 40 0.05 mm or more, when bonding the glass cover 20 and the display 30, it is possible to suppress the entrapment of air bubbles if there are minute undulations on the surface of the glass cover 20. Furthermore, by making the thickness of the adhesive layer 40 0.05 mm or more, it is possible to suppress the occurrence of perspective distortion caused by the surface of the display 30 conforming to the undulations on the surface of the glass cover 20. Furthermore, by making the thickness of the adhesive layer 40 0.05 mm or more, it is possible to suppress the entrapment of air bubbles caused by a large change in the thickness of the adhesive layer 40 around the foreign matter when a minute foreign matter is introduced. The thickness of the adhesive layer 40 is more preferably 0.1 mm or more, even more preferably 0.2 mm or more, and particularly preferably 0.3 mm or more.

[0053] On the other hand, the thickness of the adhesive layer 40 is preferably 4.0 mm or less. By setting the thickness of the adhesive layer 40 to 4.0 mm or less, it is possible to suppress the occurrence of thickness unevenness (and thus the occurrence of perspective distortion), an increase in the amount of cure shrinkage (and thus the occurrence of perspective distortion), a decrease in the reactivity of the touch sensor, and the occurrence of parallax (and thus the decrease in touch operability). The thickness of the adhesive layer 40 is more preferably 3.5 mm or less, even more preferably 3.0 mm or less, and particularly preferably 2.0 mm or less.

[0054] Next, an example of a manufacturing method for the display unit 10 will be described with reference to Figures 3 to 15. The manufacturing method includes steps S101 to S110, as shown in Figure 3, for example. Note that the manufacturing method does not necessarily have to include all of steps S101 to S110, and for example, it does not necessarily have to include steps S104 to S106. Furthermore, the manufacturing method may include steps other than steps S101 to S110.

[0055] Step S101 includes correcting the second main surface 20b of the glass cover 20 to a flat surface, as shown in Fig. 4. For example, the glass cover 20 is placed on the stage 110 with its second main surface 20b facing upward. The stage 110 horizontally adsorbs the glass cover 20 from below, thereby correcting the second main surface 20b of the glass cover 20 to be horizontal. Note that although the second main surface 20b is an upwardly convex curved surface before being corrected to be horizontal, it may also be a downwardly convex curved surface.

[0056] Step S102 includes applying a liquid curable resin composition to the second main surface 20b of the glass cover 20 after the second main surface 20b has been flattened, as shown in Fig. 5. With the second main surface 20b flattened, the curable resin composition can be applied with a uniform thickness, and the adhesive layer 40 can be formed with a uniform thickness. As a result, poor adhesion can be suppressed. Poor adhesion can include at least one of perspective distortion, entrapment of air bubbles, and wrinkles in the adhesive layer 40 due to uneven stress in the adhesive layer 40.

[0057] The method for applying the curable resin composition is, for example, a die coating method, a spray coating method, or a blade coating method. In these cases, it is preferable to correct the second main surface 20b of the glass cover 20 to be horizontal. Gravity can reduce thickness unevenness. However, the method for applying the curable resin composition is not particularly limited, and may be, for example, a dip coating method. In the case of a dip coating method, it is preferable to correct the second main surface 20b of the glass cover 20 to be vertical.

[0058] One of the reasons for applying the curable resin composition to the glass cover 20 rather than the display 30 is that the display 30 has a polarizing film on its first main surface 30a. The polarizing film is, for example, a linear polarizing film or a circular polarizing film. When the polarizing film comes into contact with the curable resin composition, it inhibits its curing. Applying the curable resin composition to the glass cover 20 can prevent the curing of the curable resin composition from being insufficient. Note that the display 30 does not need to have a polarizing film on its first main surface 30a.

[0059] Another reason for applying the curable resin composition to the glass cover 20 instead of the display 30 is that the second main surface 20b of the glass cover 20 is larger than the first main surface 30a of the display 30. If the curable resin composition is applied to the glass cover 20, the adhesive layer 40 can be formed to be larger than the first main surface 30a of the display 30, and the entire first main surface 31a of the display 30 can be covered with the adhesive layer 40.

[0060] 6, step S103 includes at least partially curing the curable resin composition layer 40A in a state in which the second main surface 20b of the glass cover 20 is corrected to a flat surface. Here, partial curing refers to a state in which the curing reaction of the curable resin composition is not completely completed and the curing reaction progresses thereafter by further irradiation with light or heating. By at least partially curing the curable resin composition layer 40A, the adhesion between the adhesive layer 40 formed by curing the curable resin composition layer 40A and the display 30 is improved.

[0061] In step S103, curing is preferably performed at least until the viscosity of the curable resin composition layer 40A reaches 80 Pa·s. In this specification, the viscosity of the curable resin composition is measured at 25°C using a Brookfield viscometer with an LV4 spindle at a rotation speed of 3 rpm. When the curable resin composition is a photocurable resin composition, curing is preferably performed by irradiating the curable resin composition layer 40A with light from a light source 111. The irradiated light is preferably near-ultraviolet light (wavelength: 200 nm to 380 nm).

[0062] If the second main surface 20b of the glass cover 20 is straightened to a flat surface at least until the viscosity of the curable resin composition layer 40A reaches 80 Pa s, the curable resin composition will not drip due to gravity even if the external force for straightening is subsequently removed, and the thickness of the curable resin composition layer 40A will hardly vary locally. Therefore, the adhesive layer 40 can be formed with a uniform thickness.

[0063] In order to suppress fluctuations in the thickness of the curable resin composition layer 40A, it is more preferable to correct the second main surface 20b of the glass cover 20 to a flat surface at least until the viscosity of the curable resin composition layer 40A reaches 120 Pa s. It is even more preferable to correct the second main surface 20b of the glass cover 20 to a flat surface at least until the viscosity of the curable resin composition layer 40A reaches 140 Pa s.

[0064] 7, step S104 includes removing the external force that corrects the second main surface 20b of the glass cover 20 to a flat surface after the viscosity of the curable resin composition layer 40A reaches 80 Pa·s. ｍａｘ ) and minimum value (T ｍｉｎ ) difference (T ｍａｘ -T ｍｉｎ ) is the average value (T ａｖｅ ) two seconds after the external force for correcting the second main surface 20b of the glass cover 20 to a flat surface is removed. ｍａｘ -T ｍｉｎ ) is T ａｖｅ It is more preferable that the content is 5% or less, and even more preferable that the content is 4% or less.

[0065] In this specification, the thickness distribution of the curable resin composition layer 40A is determined by the following method. Thickness of the curable resin composition layer 40A: Using a commercially available optical variation sensor, the thickness of the curable resin composition layer 40A is determined as the difference in height between the height of the second main surface 20b of the glass cover 20 and the height of the surface of the curable resin composition layer 40A 2 seconds after the viscosity of the curable resin composition layer 40A reaches 80 Pa·s. Thickness distribution of the curable resin composition layer 40A: The thickness of the curable resin composition layer 40A is measured at 0.75 mm intervals. When the liquid curable resin composition is applied in one direction, the thickness is measured along two directions, the MD direction (the direction in which the liquid curable resin composition is applied) and the TD direction (the direction perpendicular to the MD direction). When the effective coating width is defined as a range of 90% from the center point of the coating width of the curable resin composition layer 40A in the MD direction and the TD direction, the average thickness (T ａｖｅ ), maximum value (T ｍａｘ ) and the minimum value (Tｍｉｎ ) and (T ｍａｘ -T ｍｉｎ ) / T ａｖｅ When the liquid curable resin composition is applied in one direction, the (T ｍａｘ -T ｍｉｎ ) / T ａｖｅ It is preferable that ×100(%) is 6% or less.

[0066] It is more preferable to remove the external force for correcting the second main surface 20b of the glass cover 20 to a flat surface before the viscosity of the curable resin composition layer 40A reaches 200 Pa·s. ｍａｘ ) and minimum value (T ｍｉｎ ) difference (T ｍａｘ -T ｍｉｎ ) is the average value (T ａｖｅ ), the curable resin composition layer 40A is formed with a uniform thickness on the glass cover 20. Thereafter, by removing the external force, the glass cover 20 elastically recovers, and the second main surface 20b of the glass cover 20 returns to a curved state.

[0067] Thereafter, the curable resin composition layer 40A can flow to follow the elastic recovery of the glass cover 20. Therefore, before the viscosity of the curable resin composition layer 40A reaches 200 Pa·s, the stress remaining in the adhesive layer 40 can be reduced. As a result, perspective distortion caused by uneven stress in the adhesive layer 40 can be reduced. It is more preferable to remove the external force that straightens the second main surface 20b of the glass cover 20 to a flat surface before the viscosity of the curable resin composition layer 40A reaches 100 Pa·s.

[0068] In order to reduce residual stress in the adhesive layer 40, it is more preferable to remove the external force that straightens the second main surface 20b of the glass cover 20 into a flat surface before the viscosity of the curable resin composition layer 40A reaches 180 Pa s. It is further preferable to remove the external force that straightens the second main surface 20b of the glass cover 20 into a flat surface before the viscosity of the curable resin composition layer 40A reaches 160 Pa s.

[0069] As shown in FIG. 8, step S105 involves curing the curable resin composition layer 40A while the second main surface 20b of the glass cover 20 has a curved surface. If the curable resin composition is a photocurable resin composition, curing involves irradiating the curable resin composition layer 40A with light from a light source 121. The irradiated light is preferably near-ultraviolet light (wavelength: 200 nm to 380 nm). Step S105 allows the curable resin composition to be sufficiently cured, resulting in the adhesive layer 40. Note that if the curing of the curable resin composition has progressed sufficiently in step S103, step S105 may not be performed (see FIG. 16).

[0070] In step S105, the glass cover 20 is preferably placed on the stage 120 with its second main surface 20b facing upward. The stage 120 holds the second main surface 20b in a desired shape by adsorbing the glass cover 20 from below. The desired shape may be the shape of the glass cover 20 when not elastically deformed, or the shape when attached to the housing 50. The desired shape may be closer to the final shape than a flat shape. The final shape is, for example, the shape when attached to the housing 50. It is sufficient if the stress remaining in the adhesive layer 40 can be reduced.

[0071] The manufacturing method of the display unit 10 does not have to include steps S104 and S105 (see FIG. 17). In that case, step S103 is performed by adjusting the maximum thickness (T ｍａｘ ) and minimum value (T ｍｉｎ ) difference (T ｍａｘ -T ｍｉｎ ) is the average value (T ａｖｅ) or less. Preferably, the curing is carried out at least until the viscosity of the curable resin composition layer 40A reaches 200 Pa·s. By proceeding with the curing of the curable resin composition layer 40 until the curable resin composition layer 40A becomes unable to flow, it is possible to suppress fluctuations in the thickness of the curable resin composition layer 40A, and it is possible to form the adhesive layer 40 with a more uniform thickness. In either case, whether or not steps S104 to S105 are performed, the maximum thickness (T ｍａｘ ) and minimum value (T ｍｉｎ ) difference (T ｍａｘ -T ｍｉｎ ) is the average value (T ａｖｅ ) is preferably 6% or less.

[0072] As shown in FIG. 9 , step S106 includes activating the surface 40b of the adhesive layer 40 that contacts the display 30 with ultraviolet light. Step S106 may be performed after the external force that flattens the second main surface 20b of the glass cover 20 has been removed, or after the second main surface 20b of the glass cover 20 has been flattened. The ultraviolet light irradiated in step S106 is preferably vacuum ultraviolet light. The vacuum ultraviolet light has a wavelength of 10 nm to 200 nm. Note that ultraviolet light (wavelength: 190 nm to 360 nm) from an excimer laser or excimer lamp can also be used. A light source 131 irradiates the surface 40b of the adhesive layer 40 with ultraviolet light. Activation by ultraviolet light may be performed in a vacuum atmosphere or in an atmosphere with an oxygen concentration of 1% by mass or less. Note that instead of the light source 131, a plasma generator (not shown) may irradiate the surface 40b of the adhesive layer 40 with plasma. By irradiating the surface 40b of the adhesive layer 40 with ultraviolet light or plasma, the adhesive strength can be improved.

[0073] In step S106, the glass cover 20 is preferably placed on the stage 130 with its second main surface 20b facing upward. The stage 130 holds the second main surface 20b in a desired shape by adsorbing the glass cover 20 from below. The stage 130 may be the same as the stage 120 shown in FIG. 8 .

[0074] In step S106, stage 130 may be different from stage 120 shown in Fig. 8 or may be the same as stage 110 shown in Fig. 6. In other words, stage 130 may horizontally suction glass cover 20 from below, thereby correcting second main surface 20b of glass cover 20 to be horizontal.

[0075] 10 , step S107 includes aligning the second main surface 20b of the glass cover 20 and the first main surface 30a of the display 30 by facing them. The alignment includes capturing images of the alignment marks of the glass cover 20 and the alignment marks of the display 30 with a camera. Images of the edges may be captured instead of the alignment marks.

[0076] In step S107, the glass cover 20 is preferably placed on the stage 140 with its second main surface 20b facing upward. The stage 140 holds the second main surface 20b in a desired shape by adsorbing the glass cover 20 from below. The stage 140 may be the same as the stage 120 shown in FIG. 8 .

[0077] In step S107, stage 140 may be different from stage 120 shown in Fig. 8 or may be the same as stage 110 shown in Fig. 6. In other words, stage 140 may horizontally suction glass cover 20 from below, thereby correcting second main surface 20b of glass cover 20 to be horizontal.

[0078] In step S107, the display 30 is preferably attached to the stage 150 with its first main surface 30a facing downward. The stage 150 holds the first main surface 30a in a desired shape by adsorbing the display 30 from above. In this embodiment, the stage 150 holds the display 30 in a curved shape, but it may also hold the display 30 in a flat shape.

[0079] In step S107, the positions of the two stages 140 and 150 may be reversed. The stage 140 may adsorb the glass cover 20 from above with the second main surface 20b of the glass cover 20 facing downward. The stage 150 may adsorb the display 30 from below with the first main surface 30a of the display 30 facing upward.

[0080] Step S108 involves bonding the glass cover 20 and the display 30 together with the adhesive layer 40 sandwiched therebetween, as shown in FIG. The bonding is preferably performed in a vacuum atmosphere to prevent the inclusion of air bubbles. After step S108, the vacuum atmosphere is switched to an air atmosphere. At this time, heating at approximately 80° C. may be performed to complete the bonding between the glass cover 20 and the display 30.

[0081] Step S109 involves checking whether steps S106 to S108 have been performed a set number of times. The set number of times may be one or more. When multiple displays 30 are attached to one glass cover 20 and steps S106 to S108 are performed for each display 30, the set number of times is multiple.

[0082] If steps S106 to S108 have not been performed the set number of times (step S109, NO), steps S106 to S108 are performed again (see FIGS. 12 to 14). On the other hand, if steps S106 to S108 have been performed the set number of times (step S109, YES), the process proceeds to step S110.

[0083] Step S110 includes removing air bubbles. The removal of air bubbles is performed, for example, at room temperature and atmospheric pressure. Alternatively, the removal of air bubbles may be performed at high temperature and pressure using an autoclave or the like. The removal of air bubbles includes at least one of diffusing the air bubbles into the adhesive layer 40 and removing the air bubbles from the adhesive layer. As a result, the display unit 10 is obtained as shown in FIG. 15.

[0084] 15 , the display unit 10 may include a plurality of displays 30. In this case, the manufacturing method for the display unit 10 may involve simultaneously performing activation (step S106) and bonding (step S108) on the plurality of displays 30, or may involve performing activation (step S106) and bonding (step S108) on each display 30. When performing activation and bonding on each display 30, activation (step S106) is performed on the adhesive layer 40 that is to come into contact with one of the plurality of displays 30, but is not performed on the adhesive layers 40 that are to come into contact with the remaining displays 30. By performing activation immediately before bonding, the quality of bonding can be improved.

[0085] In this embodiment, the adhesive layer 40 that comes into contact with one display 30 and the adhesive layer 40 that comes into contact with another display 30 are provided separately, but they may be provided in a continuous manner. In this case, activation (step S106) is performed on the area that one of the multiple displays 30 is expected to come into contact with, and activation is not performed on the areas that the remaining displays 30 are expected to come into contact with.

[0086] Next, examples of the present disclosure will be described. Example 1 is an example, and Example 2 is a comparative example.

[0087] [Example 1] [Glass Cover Production] A glass plate (Dragontrail (registered trademark), manufactured by AGC, before chemical strengthening) with a square main surface and a thickness of 1.0 mm and a planar size of 392 mm x 211 mm was used to obtain a glass plate having a curved surface portion by the following procedure. The glass plate was subjected to a forming process to obtain a glass plate having a curved shape. The specific process is as follows. First, both sides of the glass plate were polished by 3 μm each using a cerium oxide polishing solution. The glass plate was then washed and dried. The glass plate was placed on a forming mold and heated to approximately 750°C to soften the glass plate and conform to the forming mold. The curved shape of the forming mold was transferred to obtain a glass plate having a curvature R1 and a curved shape overall. At this time, the curvature R1 was set to 2000 mm. The glass plate having a curved shape overall was gradually cooled to room temperature to obtain a glass plate having a curved shape. The obtained glass plate having a curved shape was called glass cover 20.

[0088] [Fabrication of Display Unit] (1) S101: The second main surface 20b (convex upward) of the glass cover 20 was placed on the stage 110. The stage 110 horizontally attracted the glass cover 20 from below using an air cylinder (not shown), thereby correcting the second main surface 20b of the glass cover 20 to a horizontal position. (2) S102: Using a head coater (Hirata Corporation, Coater System HCLE), a delayed-curing silicone-based photocurable resin composition was applied along the long side of the glass cover 20 to the second main surface 20b of the horizontally corrected glass cover 20. The photocurable resin composition was liquid and was applied uniformly over the entire surface of the glass cover 20, excluding the periphery. (3) S103: With the second main surface 20b of the glass cover 20 corrected to a flat surface, the curable resin composition layer was irradiated with light from the light source 111 to partially cure. The irradiation conditions were as follows: Light source: Ushio Inc., U365A-J95 Irradiation light: near ultraviolet (wavelength: 365 nm, UV output: 280 mV) Distance between light source and center surface of curable resin composition layer: 10 mm Irradiation intensity: 3920 mW / cm ２Irradiation for 14 seconds under the above conditions results in a partially cured photocurable resin composition layer. (4) S104 Immediately after the viscosity of the curable resin composition layer reaches 80 Pa·s, the suction by the air cylinder is gradually released, and the stage 110 and the glass cover 20 are peeled off. As a result, the glass cover 20 elastically recovers, and a glass cover 20 having a curved second main surface 20b is obtained. Two seconds after the glass cover 20 is peeled off, the effective application width of the curable resin composition layer 40A is 275 mm in the MD direction and 156 mm in the TD direction. ｍａｘ -T ｍｉｎ ) is T ａｖｅ 1.7% of the TD direction (T ｍａｘ -T ｍｉｎ ) is T ａｖｅ The viscosity is 1.5% of the original viscosity. (5) S105: The glass cover 20 is placed on the stage 120 with the second main surface 20b facing upward. The stage 120 has the same shape as when the glass cover 20 is not elastically deformed, and adsorbs the glass cover 20 from below. It was confirmed that the viscosity of the curable resin composition layer 40A reaches 200 Pa·s and is unable to flow when the stage 120 adsorbs the glass cover 20 from below. (6) S106: Plasma is irradiated from a plasma generator onto the surface 40b of the adhesive layer 40 that comes into contact with the display 30, thereby activating the surface 40b of the adhesive layer 40. (7) S107: The second main surface 20b of the glass cover 20 and the first main surface 30a of the display 30 are aligned and positioned opposite each other. A liquid crystal display (1.1 mm thick, 318 mm x 160 mm in plan view) is used as the display 30. (8) S108 The glass cover 20 and the display 30 are bonded together with the adhesive layer 40 sandwiched therebetween. The bonding is performed in a vacuum atmosphere. (9) S109 It is confirmed that steps S106 to S108 have been performed once. (10) S110 Air bubbles are removed using an autoclave at 25°C and 6 atmospheres, and the display unit of Example 1 is obtained.

[0089] [Example 2] After preparing the glass cover 20 in the same manner as in Example 1, the glass cover 20 was placed on the stage 120 with the second main surface 20b (convex upward) facing upward. Without correcting the glass cover 20 to a flat surface, the same liquid silicone-based photocurable resin composition as in Example 1 was uniformly applied over the entire surface of the second main surface 20b of the glass cover 20 using the same coater as in Example 1. Next, irradiation was performed under the same irradiation conditions as in (3) of Example 1, resulting in a partially cured photocurable resin composition layer. After the viscosity of the curable resin composition layer reached 80 Pa·s, steps S105 to S110 were performed in the same manner as in Example 1, with the stage 120 still adsorbing the glass cover 20 from below, to obtain the display unit of Example 2.

[0090] [Evaluation] (Post-Lamination Visibility Test) For the display units of Examples 1 and 2, a flat light was applied from the back of the display, and the state of the adhesive layer 40 was visually observed from the first main surface 20 a of the glass cover 20 .

[0091] In the adhesive layer of the display unit of Example 2 (Comparative Example), perspective distortion, trapped air bubbles, and wrinkles in the adhesive layer due to uneven stress in the adhesive layer were observed mainly near the center. The reason for this is thought to be that in the adhesive layer of the display unit of Example 2, the distance from the light source increases as you move from the center to the periphery of the adhesive layer, so it takes longer to cure, and part of the curable resin composition flows out from the periphery of the adhesive layer toward the center.

[0092] On the other hand, in the adhesive layer of the display unit of Example 1 (Example), no perspective distortion, trapped air bubbles, or wrinkles in the adhesive layer 40 due to uneven stress in the adhesive layer were observed. This confirms that the manufacturing method of the present invention can form an adhesive layer of uniform thickness on the curved surface of the glass cover, and can suppress the occurrence of poor adhesion.

[0093] The following supplementary notes are disclosed in relation to the above embodiments. [Supplementary Note 1] A method for manufacturing a display unit, comprising: applying a liquid curable resin composition to a main surface of a glass cover, the main surface of which is a glass plate having a curved surface, while the main surface of the glass cover is straightened to a flat surface, to form a curable resin composition layer; at least partially curing the curable resin composition layer while the main surface of the glass cover is straightened to a flat surface; and bonding the glass cover and a display together with an adhesive layer formed by curing the curable resin composition layer. [Supplementary Note 2] A method for manufacturing a display unit according to Supplementary Note 1, wherein immediately before bonding the glass cover and the display, the difference between the maximum and minimum thicknesses of the curable resin composition layer is 6% or less of the average. [Supplementary Note 3] A method for manufacturing a display unit according to Supplementary Note 1 or 2, wherein the curable resin composition layer is cured while the main surface of the glass cover is straightened to a flat surface, at least until the viscosity of the curable resin composition layer reaches 80 Pa s. [Appendix 4] A method for manufacturing a display unit according to Appendix 3, comprising: removing an external force that corrects the main surface of the glass cover to a flat surface before the viscosity of the curable resin composition layer reaches 200 Pa s; and curing the curable resin composition layer while the main surface of the glass cover is curved, to form the adhesive layer. [Appendix 5] A method for manufacturing a display unit according to Appendix 3, comprising curing the curable resin composition layer while the main surface of the glass cover is corrected to a flat surface, until the viscosity of the curable resin composition layer reaches at least 200 Pa s. [Appendix 6] A method for manufacturing a display unit according to any one of Appendices 1 to 5, wherein the display has a polarizing film on a main surface that contacts the adhesive layer. [Appendix 7] A method for manufacturing a display unit according to any one of Appendices 1 to 6, wherein the main surface of the glass cover is larger than the main surface of the display that contacts the adhesive layer. [Appendix 8] The method for manufacturing a display unit according to any one of Appendices 1 to 7, wherein the glass plate having the curved surface portion is a glass plate that has been subjected to hot bending processing in advance.[Appendix 9] The method for manufacturing a display unit according to any one of Appendices 1 to 8, wherein the curable resin composition is a photocurable resin composition. [Appendix 10] The method for manufacturing a display unit according to any one of Appendices 1 to 9, further comprising activating a surface of the adhesive layer that comes into contact with the display with ultraviolet light or plasma after forming the adhesive layer and before bonding the glass cover and the display with the adhesive layer sandwiched between them. [Appendix 11] The method for manufacturing a display unit according to Appendices 10, wherein the display unit has a plurality of the displays, and the manufacturing method performs the activation and the bonding for each display.

[0094] The above describes a manufacturing method for a display unit according to the present disclosure, but the present disclosure is not limited to the above-described embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These naturally fall within the technical scope of the present disclosure.

[0095] This application claims priority based on Japanese Patent Application No. 2023-184246 filed with the Japan Patent Office on October 26, 2023, the entire contents of which are incorporated herein by reference.

[0096] 10 Display unit 20 Glass cover 30 Display 40 Adhesive layer

Claims

1. A method for manufacturing a display unit, comprising: applying a liquid curable resin composition to a main surface of a glass cover, the main surface of which is corrected to be flat, the main surface of the glass cover including a glass plate having a curved portion, to form a curable resin composition layer; at least partially curing the curable resin composition layer in a state in which the main surface of the glass cover is corrected to be flat; and bonding the glass cover and a display with an adhesive layer formed by curing the curable resin composition layer sandwiched between the glass cover and the display.

2. The method for manufacturing a display unit according to claim 1, wherein the difference between the maximum and minimum thicknesses of the adhesive layer immediately before bonding the glass cover and the display is 6% or less of the average value.

3. A method for manufacturing a display unit as described in claim 1 or 2, wherein the curable resin composition layer is cured while the main surface of the glass cover is corrected to a flat surface, at least until the viscosity of the curable resin composition layer reaches 80 Pa·s.

4. A method for manufacturing a display unit as described in claim 3, comprising: removing the external force that straightens the main surface of the glass cover to a flat surface before the viscosity of the curable resin composition layer reaches 200 Pa·s; and curing the curable resin composition layer while the main surface of the glass cover has a curved surface, thereby forming the adhesive layer.

5. A method for manufacturing a display unit as described in claim 3, comprising curing the curable resin composition layer while the main surface of the glass cover is corrected to a flat surface, at least until the viscosity of the curable resin composition layer reaches 200 Pa·s.

6. The method for manufacturing a display unit according to claim 1 or 2, wherein the display has a polarizing film on a main surface in contact with the adhesive layer.

7. The method for manufacturing a display unit according to claim 1 or 2, wherein the main surface of the glass cover is larger than the main surface of the display that contacts the adhesive layer.

8. The method for manufacturing a display unit according to claim 1 or 2, wherein the glass plate having the curved surface portion is a glass plate that has been hot bent in advance.

9. The method for manufacturing a display unit according to claim 1 or 2, wherein the curable resin composition is a photocurable resin composition.

10. A method for manufacturing a display unit as described in claim 1 or 2, comprising, after forming the adhesive layer and before bonding the glass cover and the display with the adhesive layer in between, activating the surface of the adhesive layer that comes into contact with the display with ultraviolet light or plasma.

11. The method for manufacturing a display unit according to claim 10, wherein the display unit has a plurality of displays, and the manufacturing method includes performing the activating and bonding for each display.