发明内容：
[0005]However, in the conventional expression method disclosed in Patent Document 1, there is a problem as follows. That is, since a pattern shape such as a design should be made to be recognized by contrast, it is necessary to use different inks in the metal base color layer and the design layer, and thus a printing step becomes complicated. In addition, when the printed layer is visually recognized from a surface on which the printed layer is not formed, through the print target plate, there are some cases that difference (contrast) in color of the printed layer comes to be visually recognized and thus, a desired design cannot be obtained.
[0006]An object of the present invention is to provide, with a simple step, a plate with a printed layer in which contrast of the printed layer can be visually recognized only when the printed layer is visually recognized from a surface on which the printed layer is formed, to provide a manufacturing method thereof, and to provide a display device.
[0007]A plate with a printed layer according to the present invention, includes a plate having a bent portion, a lower printed layer, and an upper printed layer provided at a portion of the lower printed layer, in which at least a portion of the lower printed layer is provided at a position corresponding to the bent portion on a main surface of the plate.
[0008]According to the present invention, for example, whether an ink in the lower printed layer is the same as or different from an ink in the upper printed layer, a difference in thickness occurs between a single-layer portion of the lower printed layer, at which the upper printed layer is not provided, and a multi-layer portion of the lower printed layer, at which the upper printed layer is provided. Therefore, when the plate with a printed layer is irradiated with light, contrast can be visually recognized only in the case where the printed layer is visually recognized from a surface on which the printed layer is formed. Thus, using the same ink is not necessarily required for forming the lower printed layer and the upper printed layer. Accordingly, the printed layer having contrast can be formed on the plate with a simple step.
[0009]In a manufacturing step of a product using the plate with a printed layer which has a bent portion, positioning of the plate with a printed layer to a casing and the like has been difficult. However, the positioning is easily performed by using the multi-layer portion as an alignment mark and the like.
[0010]In the plate with a printed layer in the present invention, it is preferred that the lower printed layer includes a first printed layer and a second printed layer which are provided in regions of the main surface to be adjacent to each other, and the upper printed layer is configured of a portion of the second printed layer provided on the first printed layer.
[0011]According to this aspect of the present invention, the upper printed layer can be simultaneously formed when the second printed layer is formed and thud, the printed layer having contrast can be formed on the plate with a simple step.
[0012]In the plate with a printed layer in the present invention, a plurality of upper printed layers are preferably provided.
[0013]According to this aspect of the present invention, two-dimensional or three-dimensional positioning of the plate with a printed layer is easily performed by using a plurality of multi-layer portions as alignment marks and the like.
[0014]In the plate with a printed layer in the present invention, the sizes of the plurality of upper printed layers in plan view are preferably different from each other.
[0015]According to this aspect of the present invention, the multi-layer portions having different sizes can be used as respective alignment marks and the like. Therefore, for example, a plurality of the plates with a printed layer can be placed such that the alignment marks and the like having the same predetermined size of the respective plates are at the same position on a casing. In addition, this placing work can be accurately and easily performed.
[0016]In the plate with a printed layer in the present invention, the upper printed layer has a thickness of preferably from 0.5 μm to 8 μm.
[0017]According to this aspect of the present invention, in plan view, contrast between the single-layer portion and the multi-layer portion can be easily and clearly provided.
[0018]In the plate with a printed layer in the present invention, a ratio of the thickness of the single-layer portion of the lower printed layer, at which the upper printed layer is not provided to the thickness of the multi-layer portion thereof at which the upper printed layer is provided is preferably 0.6 or greater.
[0019]According to this aspect of the present invention, in plan view, contrast between the single-layer portion and the multi-layer portion can be easily and clearly provided.
[0020]In the plate with a printed layer in the present invention, it is preferable that unevenness is provided at an outer edge of the lower printed layer in plan view and a difference between the maximum value and the minimum value of the unevenness is 40 μm or smaller.
[0021]According to this aspect of the present invention, a boundary in the plate with a printed layer between a non-printing region in which the lower printed layer is not provided and the single-layer portion can be formed in a straight line or a curved line without unevenness. Thus, favorable aesthetics can be realized. The term of “difference between the maximum value and the minimum value of the unevenness” means a difference between the most protruding portion and the most recessed portion in a planar direction when the outer edge of the printed layer is observed from the top.
[0022]In the plate with a printed layer in the present invention, it is preferable that the plate is a transparent plate and the lower printed layer is provided at at least a portion of a circumferential region of the main surface.
[0023]According to this aspect of the present invention, a region of the transparent plate other than the circumferential region thereof can be served as a non-printing region, and a display panel and the like can be disposed at a position facing the non-printing region.
[0024]A wiring of the display panel and the like can be hidden by the single-layer portion and the multi-layer portion, and favorable aesthetics can be realized.
[0025]Furthermore, leakage of light from the display panel can be suppressed by the single-layer portion and the multi-layer portion. In particular, in the case where the lower printed layer is provided in a frame shape and the display panel is disposed within the frame, light of the display panel is easily leaked from the corner in the inner edge of the frame. However, the leakage of light can be more suppressed in a manner that the multi-layer portion is formed by providing the upper printed layer in a region adjacent to the corner.
[0026]In the plate with a printed layer in the present invention, the plate is preferably glass.
[0027]According to this aspect of the present invention, the plate with a printed layer having high strength and favorable texture can be provided by using glass as the plate.
[0028]In the plate with a printed layer in the present invention, the glass is preferably a tempered glass.
[0029]According to this aspect of the present invention, the plate with a printed layer which has excellent strength and scratch resistance can be provided by using a tempered glass as the glass.
[0030]A display device according to the present invention, includes the above-described plate with a printed layer, a display panel and an adhesive layer for bonding the plate with a printed layer and the display panel to each other, in which the plate constituting the plate with a printed layer is a transparent plate.
[0031]According to the present invention, the multi-layer portion can be used as alignment marks and the like. Therefore, positioning of the plate with a printed layer, which is used as a cover member, is easily performed and the display device is easily manufactured. Also, a worker can instantaneously determine the correct orientation of the plate with a printed layer and thus, work efficiency by the worker can be improved.
[0032]A manufacturing method of a plate with a printed layer according to the present invention, which is a method of forming a printed layer on a main surface of a plate by using an ink jet method, includes forming a first printed layer in a first region and forming a second printed layer which continues from a portion on the first printed layer to a second region adjacent to the first region.
[0033]According to the present invention, the printed layer having contrast imparted by the single-layer portion and the multi-layer portion can be formed with a simple step in which, when the second printed layer is formed by relatively moving nozzles and the plate while an ink is discharged, the nozzles are positioned on the first printed layer when discharging starts or ends.
[0034]Since the second printed layer is formed from the second region over the first printed layer, the printed layer can be reliably formed at a boundary between the first region and the second region and favorable aesthetics can be realized.
[0035]Furthermore, the difference between the maximum value and the minimum value of an unevenness at the outer edge of the lower printed layer including the first printed layer and the second printed layer can be set to be 40 μm or smaller, and a boundary between the non-printing region and the single-layer portion in the plate with a printed layer can be formed in a straight line or a curved line without unevenness. Thus, favorable aesthetics can be realized.
[0036]In the manufacturing method of a plate with a printed layer according to the present invention, the second printed layer is preferably formed such that the thickness of a portion on the first printed layer, on which the second printed layer is formed, is thinner than the thickness of a portion on the second region.
[0037]According to this aspect of the present invention, spreading of wetting on the first printed layer can be suppressed by setting the thickness of the portion on the first printed layer, on which the second printed layer is formed, to be thin and thus, the alignment marks and the like having high contrast can be obtained.
[0038]In the manufacturing method of a plate with a printed layer according to the present invention, it is preferable that the plate has a bent portion, and at least a portion of the first printed layer is formed at a position corresponding to the bent portion in the main surface.
[0039]According to this aspect of the present invention, the plate with a printed layer in which positioning is easily performed can be provided.
具体实施方式：
[0051]Definitions of the following terms are applied over this Specification and Claims.
[0052]The “flat portion” means a portion having an average curvature radius of greater than 10,000 mm.
[0053]The “bent portion” means a portion having an average curvature radius of 10,000 mm or smaller.
[0054]The “bending depth” means, in sectional view in a thickness direction of a plate having a bent portion (also described as a “bent plate” below), a distance between a line segment joining two end portions and a tangent line at the bent portion of the bent plate which is parallel to the line segment. In a bent plate 2 as illustrated in FIG. 1A and FIG. 1B, the bending depth means a distance h between both ends of the bent plate 2 in a bent direction.
[0055]The “bending angle” means an angle θ formed by joining both ends of the bent portion and the curvature radius center O, in sectional view in the thickness direction as illustrated in FIG. 1B. Descriptions will be made on the assumption that a bent portion having a constant curvature radius is used as an example. However, the bent plate may have a bent portion having a curvature radius which continuously changes. In this case, the curvature radius center O may be set as the center of an average curvature radius between the maximum value and the minimum value of the curvature radius.
[0056]The “twist structure” means a structure in which portions having different curvature radius are provided in the same bent portion 2A, for example, a structure in which a curved shape having a curvature radius R1 is provided on one end side of the bent portion 2A and another curved shape having a curvature radius R2 smaller than R1 is provided on the other end side thereof in the bent plate 2 as illustrated in FIG. 2A and FIG. 2B.
[0057]The “optical density (OD value)” is the absolute value of a value obtained by expressing a ratio of the transmitted light amount T of certain light which has passed through a measurement target object to the incident light amount I of the certain light, in common logarithm with the base of 10. The OD value indicates hiding performance.
[0058]For example, when the incident light amount is 1000 and the transmitted light amount is 1 regarding visible light having a wavelength of 500 nm, the OD value at this time is calculated as |Log10( 1/1000)|=3. The OD value can be measured by using an OD measuring device (manufactured by Lambda Vision Inc., product name: LV-RTM).
[0059]The “average” means arithmetic mean of pieces of data of five points, unless otherwise specified.
EMBODIMENT
[0060]Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Configuration of Plate with Printed Layer
[0061]First, a configuration of the plate with a printed layer will be described.
[0062]A plate 1 with a printed layer illustrated in FIG. 3 includes a bent plate 2 as a transparent plate, a left-side printed layer 31 as a first printed layer, a right-side printed layer 32 as another first printed layer, an upper-side printed layer 33 as a second printed layer, and a lower-side printed layer 34 as another second printed layer.
[0063]The bent plate 2 is a transparent tempered glass of rectangular in plan view. The center of the rectangle in a longitudinal direction is formed to be curved and recessed to a second main surface 22 side in comparison to both ends thereof. The entirety of the bent plate 2 constitutes a bent portion. The bent plate 2 includes a first main surface 21, the second main surface 22, and an end surface 23. A chamfered portion 24 is provided on the end surface 23.
[0064]A pair of long sides constituting the rectangle is referred to as an upper side and a lower side below. A pair of short sides is referred to as a left side and a right side below. A short-side direction is referred to as a “vertical direction” and a long-side direction is referred to as a “horizontal direction”.
[0065]The printed layers 31 to 34 are provided in order to impart a light shielding property to the plate 1 with a printed layer. The left-side printed layer 31 is provided in a left-side region 251 as a first region which extends in a vertical direction along the left side and has a rectangular shape, in a circumferential region of the first main surface 21, which has a square frame shape. The right-side printed layer 32 is provided in a right-side region 252 as a first region which extends along the right side and has the same shape as the left-side region 251, in the circumferential region. The upper-side printed layer 33 and the lower-side printed layer 34 are provided in an upper-side region 253 and a lower-side region 254 as a second region which extends in the horizontal direction along the upper side and the lower side and has a rectangular shape, respectively in the circumferential region.
[0066]Next, the detailed configuration of the printed layers 31 to 34 will be described with reference to FIG. 4, FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B.
[0067]FIG. 4 is a plan view illustrating the plate 1 with a printed layer when being developed on a plane. FIG. 5A and FIG. 5B are side views when the plate 1 with a printed layer is viewed from the upper side. FIG. 6A and FIG. 6B are side views when the plate 1 with a printed layer is viewed from the lower side. FIG. 5A to FIG. 6B flatly illustrate the bent plate 2 or each of the printed layers 31 to 34. However, in practice, the bent plate 2 and the printed layers 31 to 34 are curved.
[0068]As illustrated in FIG. 4, the upper-side printed layer 33 includes an upper-side single-layer portion 331, a first upper printed layer 332, a second upper printed layer 333, a first connection portion 334, and a second connection portion 335.
[0069]As indicated by two-dot chain lines in FIG. 5A and FIG. 5B, the upper-side single-layer portion 331 is a portion having a rectangular shape in side view. The upper-side single-layer portion 331 is directly provided on the first main surface 21.
[0070]The upper printed layers 332 and 333 are portions having a rectangular shape in side view, as indicated by two-dot chain lines in FIG. 5A and FIG. 5B. The first upper printed layer 332 is provided at an end portion of the left-side printed layer 31 on the upper right side. The second upper printed layer 333 is provided at an end portion of the right-side printed layer 32 on the upper left side.
[0071]The connection portions 334 and 335 are portions having a triangular shape in side view, as indicated by two-dot chain lines in FIG. 5A and FIG. 5B. The first connection portion 334 connects the left side of the upper-side single-layer portion 331 on an upper surface thereof and the right end of the first upper printed layer 332 to each other. The second connection portion 335 connects the right side of the upper-side single-layer portion 331 on the upper surface thereof and the left end of the second upper printed layer 333 to each other.
[0072]As illustrated in FIG. 4, the lower-side printed layer 34 includes a lower-side single-layer portion 341, a third upper printed layer 342, a fourth upper printed layer 343, a third connection portion 344, and a fourth connection portion 345.
[0073]As indicated by two-dot chain lines in FIG. 6A and FIG. 6B, the lower-side single-layer portion 341 is a portion having a rectangular shape in side view. The lower-side single-layer portion 341 is directly provided on the first main surface 21.
[0074]As indicated by two-dot chain lines in FIG. 6A and FIG. 6B, the upper printed layers 342 and 343 are portions having a rectangular shape. The third upper printed layer 342 is provided at an end portion of the right-side printed layer 32 on the lower left side. The fourth upper printed layer 343 is provided at an end portion of the left-side printed layer 31 on the lower right side.
[0075]The connection portions 344 and 345 are portions having a triangular shape in side view, as indicated by two-dot chain lines in FIG. 6A and FIG. 6B. The third connection portion 344 connects the right side of the lower-side single-layer portion 341 on the upper surface thereof and the left end of the third upper printed layer 342 to each other. The fourth connection portion 345 connects the left side of the lower-side single-layer portion 341 on the upper surface thereof and the right end of the fourth upper printed layer 343 to each other.
[0076]The entireties of the left-side printed layer 31 and the right-side printed layer 32 are directly provided on the first main surface 21.
[0077]As illustrated in FIG. 4, the left-side printed layer 31 includes a first multi-layer-portion constituent portion 311, a fourth multi-layer-portion constituent portion 312, and a left-side single-layer portion 313. The multi-layer-portion constituent portions 311 and 312 are portions on which the upper printed layers 332 and 343 are provided on the upper surfaces thereof, respectively. The left-side single-layer portion 313 is a portion other than the multi-layer-portion constituent portions 311 and 312.
[0078]The right-side printed layer 32 includes a second multi-layer-portion constituent portion 321, a third multi-layer-portion constituent portion 322, and a right-side single-layer portion 323. The multi-layer-portion constituent portions 321 and 322 are portions on which the upper printed layers 333 and 342 are provided on the upper surfaces thereof, respectively. The right-side single-layer portion 323 is a portion other than the multi-layer-portion constituent portions 321 and 322.
[0079]The left-side printed layer 31 and the right-side printed layer 32 as the first printed layer, and the upper-side single-layer portion 331 and the lower-side single-layer portion 341 which constitute the second printed layer, constitute the lower printed layer 35 in the present invention. The lower printed layer 35 is provided at a position corresponding to the bent portion of the first main surface 21.
[0080]The upper printed layers 332, 333, 342, and 343 are configured by a portion of the upper-side printed layer 33 or the lower-side printed layer 34 as the second printed layer, and are provided at a portion of the lower printed layer 35.
[0081]The first multi-layer-portion constituent portion 311 and the first upper printed layer 332 constitute a first multi-layer portion 361. The second multi-layer-portion constituent portion 321 and the second upper printed layer 333 constitute a second multi-layer portion 362. The third multi-layer-portion constituent portion 322 and the third upper printed layer 342 constitute a third multi-layer portion 363. The fourth multi-layer-portion constituent portion 312 and the fourth upper printed layer 343 constitute a fourth multi-layer portion 364.
[0082]As illustrated in FIG. 4, the widths W31, W32, W33, W34, and W35 of the upper-side single-layer portion 331, the upper printed layers 332 and 333, and the connection portions 334 and 335 may be equal to each other or different from each other. The widths W41, W42, W43, W44, and W45 of the lower-side single-layer portion 341, the upper printed layers 342 and 343, and the connection portions 344 and 345 may be equal to each other or different from each other. The width W10 of the left-side printed layer 31, the width W20 of the right-side printed layer 32, for example, the width W31 of the upper-side single-layer portion 331, and, for example, the width W41 of the lower-side single-layer portion 341 may be equal to each other or different from each other.
[0083]In the present embodiment, the case where all of the widths W10, W20, W31 to W35, and W41 to W45 are equal to each other is exemplified.
[0084]The lengths L32, L33, L34, and L35 of the upper printed layers 332 and 333 and the connection portions 334 and 335 may be equal to each other or different from each other. The lengths L42, L43, L44, and L45 of the upper printed layers 342 and 343 and the connection portions 344 and 345 may be equal to each other or different from each other.
[0085]In the present embodiment, when the lengths L32 and L33 are set as LA, the lengths L34, L35, L44, and L45 are set as L3, and the lengths L42 and L43 are set as LC, the case where LA is greater than LC (e.g., the length L32 is longer than the length L42) is exemplified. With such a configuration, in plan view, the size of the first multi-layer portion 361 is equal to the size of the second multi-layer portion 362, the size of the third multi-layer portion 363 is equal to the size of the fourth multi-layer portion 364, and the size of the multi-layer portions 361 and 362 is greater than the size of the multi-layer portions 363 and 364.
[0086]As illustrated in FIG. 5A, FIG. 5B, FIG. 6A, and FIG. 6B, the thicknesses T10, T20, T31, T32, T33, T41, T42, and T43 of the left-side printed layer 31, the right-side printed layer 32, the upper-side single-layer portion 331, the upper printed layers 332 and 333, the lower-side single-layer portion 341, and the upper printed layers 342 and 343 may be equal to each other or different from each other.
[0087]In the preset embodiment, when the thicknesses T10, T20, T31, and T41 are set as TA and the thicknesses T32, T33, T42, and T43 are set as TB, the case where TA is greater than TB (e.e., the thickness T31 is thicker than the thickness T32) is exemplified. Since the multi-layer portions 361, 362, 363, and 364 are thicker than the single-layer portions 313, 323, 331, and 341, contrast occurs when the plate 1 with a printed layer is irradiated with light.
[0088]The thicknesses T10, T20, T31, and T41 of the left-side printed layer 31, the right-side printed layer 32, the upper-side single-layer portion 331, and the lower-side single-layer portion 341 (lower printed layer 35) are preferably 7 μm or smaller. If the thickness is the upper limit value or smaller, contrast between the single-layer portions 313, 323, 331, and 341 and the multi-layer portions 361, 362, 363, and 364 can be easily and clearly imparted in plan view. In the case where the thickness of the lower printed layer 35 is greater than the upper limit value, a step with the region in which the printed layer is not formed is increased, and defects may be easily formed by, for example, adhesion bonding in the post step. The thicknesses T10, T20, T31, and T41 are more preferably 5 μm or smaller and further preferably 4 μm or smaller.
[0089]The lower limit value of the thicknesses T10, T20, T31, and T41 is not particularly limited, and is preferably 0.5 μm or greater. If the thickness is smaller than the lower limit value, the hiding property of the lower printed layer 35 may be deteriorated. The thicknesses T10, T20, T31, and T41 are more preferably 0.6 min or greater and further preferably 0.7 μm or greater.
[0090]The thicknesses T32, T33, T42, and T43 of the upper printed layers 332, 333, 342, and 343 are preferably 5 μm or smaller. If the thickness is the upper limit value or smaller, contrast between the single-layer portions 313, 323, 331, and 341 and the multi-layer portions 361, 362, 363, and 364 can be easily and clearly imparted in plan view. In the case where the thicknesses of the upper printed layers 332, 333, 342, and 343 are greater than the upper limit value, the upper printed layers 332, 333, 342, and 343 may be wet and spread on the lower printed layer 35. As a result, a boundary between the upper printed layers 332, 333, 342, and 343 and the lower printed layer 35 may become ambiguous in plan view, and thus it may be difficult to impart contrast. The thicknesses T32, T33, T42, and T43 are more preferably 3 μm or smaller and further preferably 2 μm or smaller.
[0091]The lower limit value of the thicknesses T32, T33, T42, and T43 is not particularly limited, and is preferably 0.5 μm or greater. The reason is because, if the thickness is smaller than the lower limit value, it may be difficult to impart contrast and to use the layers as the alignment mark and the like. The thicknesses T32, T133, 142, and T43 are more preferably 0.6 μm or greater and further preferably 0.7 μm or greater.
[0092]Measurement of the thickness is not particularly limited. For example, arithmetic mean of a measurement area can be used as the thickness, measured by using DektakXT (manufactured by BRUKER Corporation).
[0093]A ratio α of the thickness of the lower printed layer 35 to the thicknesses of the multi-layer portions 361, 362, 363, and 364 is preferably 0.6 or greater. In the case where the ratio α is the lower limit value or greater, a step formed by the lower printed layer 35 and and the multi-layer portions 361, 362, 363, and 364 do not become too large. Thus, defects may not likely occur in the post step. The ratio ca is more preferably 0.7 or greater and further preferably 0.8 or greater.
[0094]The upper limit of the ratio α is not particularly limited and preferably 0.95 or smaller. Thus, in plan view, contrast between the single-layer portions 313, 323, 331, and 341, and the multi-layer portions 361, 362, 363, and 364 can be clearly and easily imparted. The ratio c is more preferably 0.9 or smaller.
[0095]The average value of OD values in the multi-layer portions 361, 362, 363, and 364 for visible light and the average value of OD values in the single-layer portions 313, 323, 331, and 341 are preferably 3 or greater. Thus, the hiding property can be improved by the printed layer. The lower limit value is more preferably 4 or greater.
[0096]The average value of OD values in the multi-layer portions 361, 362, 363, and 364 for visible light and the average value of OD values in the single-layer portions 313, 323, 331, and 341 are not particularly limited and preferably 8 or smaller. In the case where a printed layer having an OD value greater than the upper limit value is provided, the printed layer may be required to become thick. Thus, defects may be easily formed by, for example, bonding of an adhesive layer in the post step. The upper limit value is more preferably 7 or smaller and further preferably 6 or smaller.
[0097]An unevenness may be provided at inner edges 316, 326, 336, and 346 of the printed layers 31 to 34 on an in-plane side of the first main surface 21 in plan view, that is, at outer edges of the printed layers 31 to 34. A difference between the maximum value and the minimum value of the unevenness (simply referred to as an “unevenness difference” below) is preferably 40 μm or smaller. Thus, the boundary between the non-printing region in which the lower printed layer is not provided and the single-layer portion in the plate 1 with a printed layer can be formed by a straight line or a curved line without unevenness. Thus, favorable aesthetics can be realized. The unevenness difference is more preferably 35 μm or smaller, further preferably 50 μm or smaller, and particularly preferably 20 μm or smaller.
[0098]“The unevenness difference” means the difference between the most protruding portion and the most recessed portion in an observation surface in a planar direction when the outer edge of the printed layer is observed from the top.
[0099]As illustrated in FIG. 3, a region surrounded by the printed layers 31 to 34 in the plate 1 with a printed layer serves as a display region 4 in which a display panel such as a liquid crystal panel is disposed. In the case where the plate 1 with a printed layer is used in a display device (see FIG. 10), a display panel such as a liquid crystal panel is disposed in the display region 4. Wirings, circuits, and the like for driving are provided on the display panel. In the case where the display panel is visually recognized through the bent plate 2, if the wirings and the like are viewed, aesthetics is impaired. The wirings and the like disposed in the vicinity of an outer circumference can be hidden by providing the printed layers 31 to 34 at a circumferential portion of the bent plate 2, and aesthetics can be improved.
[0100]In the case where the display panel is a liquid crystal panel, a backlight is provided on the back surface of the liquid crystal panel. If illumination light from the backlight is leaked to the outside of the display region 4, aesthetics is impaired. The leakage of the illumination light from the outer circumference of the display region 4 can be prevented by providing the printed layers 31 to 34 at the circumferential portion of the bent plate 2, and aesthetics can be improved.
[0101]In particular, illumination light from the backlight is easily leaked from the corner at the inner edge which is configured by the printed layers 31 to 34 and has a frame shape. However, since the multi-layer portions 361 to 364 which has a thick thickness and a high light shielding property are provided in a region adjacent to the corner, the leakage of the illumination light can be suppressed more.
Manufacturing Method of Plate with a Printed Layer
[0102]Next, a manufacturing method of the plate 1 with a printed layer will be described.
[0103]First, a bent plate 2 is prepared in a manner that transparent glass is cut out to have a predetermined size and then chamfering is performed. At this time, chamfering is preferably performed such that dimensions of the chamfered portion 24 in plan view is from 0.05 mm to 0.5 mm. Then, the bent plate 2 is formed to have the bent portion as illustrated in FIG. 3. A forming method of the bent plate 2 is not particularly limited. A self-weight forming method, a vacuum forming method, and a press forming method can be exemplified.
[0104]The self-weight forming method is a method of forming a glass plate to have a predetermined shape in a manner that the glass plate is installed on a predetermined mold depending on the shape of the bent plate 2 after forming, and then the glass plate is softened and bent by gravity so as to be fit into the mold. The vacuum forming method is a method of forming a glass plate to have a predetermined shape in a manner that differential pressure is applied to the front and back surfaces of the glass plate in a state where the glass plate is softened, and thus the glass plate is bent to be fit into the mold. The press forming method is a method of forming a glass plate to have a predetermined shape in a manner that the glass plate is installed between predetermined molds (lower mold, upper mold) depending on the shape of the bent plate 2 after forming, the press load is applied to the upper and lower molds in a state where the glass plate is softened, and thus the glass plate is bent to be fit into the mold.
[0105]Then, the printed layers 31 to 34 are formed on the bent plate 2 by an ink jet method. The ink jet method is a method of forming a dot-like pattern on the bent plate 2 by discharging fine liquid droplets of a liquid ink from nozzles in a pulse manner. The bent plate 2 is positioned based on an origin point of a nozzle moving mechanism as a reference. While the nozzles discharge fine liquid droplets of the ink based on a command from a computer, the nozzles move on the surface of the bent plate 2 in a substantially horizontal direction. Thus, a dot-like ink is continuously formed, and thus a printed layer having a predetermined pattern is formed. In the case of the bent plate 2 in which a printing target surface has a bent portion, considering the distortion and the like of the pattern, a distance between the nozzles of discharging liquid droplets of the ink and the bent plate 2 is preferably made to be substantially constant. That is, use can be preferably made of a mechanism in which the nozzles or the bent plate 2 can be rotated and moved in accordance with the pattern in a state where the distance between the nozzle and the bent plate 2 is maintained to be substantially constant. Since supply pressure for supplying the ink to the nozzles can become stable and the amount of the ink discharged from the nozzles can be maintained to be constant, a mechanism of fixing the nozzles and rotating and moving the bent plate 2 with respect to the nozzles is more preferable.
[0106]Specifically, the bent plate 2 is placed on a support stand (not illustrated). As indicated by a solid line in FIG. 7A, a discharge hole 91 of a nozzle 9 is positioned at a lower left end portion of the first main surface 21 of the bent plate 2. Then, while an ink is discharged from the discharge hole 91, the nozzle 9 is moved until the discharge hole 91 is positioned at an upper left end portion of the first main surface 21, as indicated by a two-dot chain line in FIG. 7A. Thus, the left-side printed layer 31 as illustrated in FIG. 7B is printed.
[0107]Then, at least one of the support stand and the nozzle 9 is moved (the nozzle 9 and the bent plate 2 are relatively moved). Thus, as indicated by a solid line in FIG. 7B, the discharge hole 91 is positioned at a lower right end portion of the first main surface 21. Then, as indicated by the two-dot chain line in FIG. 7B, the nozzle 9 for discharging the ink is moved until the discharge hole 91 is positioned at an upper right end portion of the first main surface 21. Thus, the right-side printed layer 32 as illustrated in FIG. 8A is printed.
[0108]Then, the upper-side printed layer 33 and the lower-side printed layer 34 are printed.
[0109]When the upper-side printed layer 33 is formed, as indicated by a solid line in FIG. 8A, the discharge hole 91 is positioned over the left-side end portion of the first multi-layer-portion constituent portion 311 positioned on the right side of the upper left end side in the first main surface 21. Then, as indicated by a two-dot chain line in FIG. 8A, while the ink is discharged, the nozzle 9 is moved until the discharge hole 91 is positioned over the right-side end portion of the second multi-layer-portion constituent portion 321 positioned on the left side of the upper right end portion in the first main surface 21. Thus, the upper-side printed layer 33 as illustrated in FIG. 8B is printed.
[0110]When the lower-side printed layer 34 is formed, as indicated by a solid line in FIG. 8B, the discharge hole 91 is positioned over the left-side end portion of the fourth multi-layer-portion constituent portion 312 positioned on the right side of the left-side end portion of the first multi-layer-portion constituent portion 311. Then, as indicated by a two-dot chain line in FIG. 8B, while the ink is discharged, the nozzle 9 is moved until the discharge hole 91 is positioned over the right-side end portion of the third multi-layer-portion constituent portion 322 positioned on the left side of the right-side end portion of the second multi-layer-portion constituent portion 321 in the first main surface 21. Thus, the lower-side printed layer 34 is printed.
[0111]The thickness of the printed layers 31 to 34 can be adjusted by controlling the amount of an ink discharged from the discharge hole 91 or a moving speed of the nozzle 9. For example, in the case where the printed layer is formed to be thick, the amount of the discharged ink may be set to be large or a movement speed may be reduced. In the case where the printed layer is formed to be thin, the amount of the discharged ink may be set to be small or a movement speed may be increased.
[0112]The amount of the discharged ink can be controlled by the amount of liquid droplets discharged from the discharge hole 91 of the nozzle 9 and an interval (discharge pitch) for performing discharging. When the amount of liquid droplets from one discharge hole 91 is set as L (pL) and the discharge pitch is set as P (μm), L/P (pL/μm) and the discharge amount have a correlation. L/P is preferably 7 or smaller. If L/P is the upper limit value or smaller, the discharge amount can be stabilized and bleeding can be suppressed in the case of performing printing linearly, and thus linearity can be stabilized. In the case of performing printing to have a curved shape, ink drooping can be suppressed and a desired curve shape can be obtained. L/P is more preferably 6 or smaller and further preferably 4 or smaller.
[0113]L/P is preferably 0.5 or greater. If L/P is the lower limit value or greater, the thickness or printing quality suitable for printing and the like for obtaining the light shielding property can be obtained, and a favorable printed layer can be obtained. L/P is more preferably 0.6 or greater, and further preferably 0.8 or greater.
[0114]The relative moving speed between the nozzle 9 and the bent plate 2 is preferably 250 mm/s or lower. If the relative moving speed between the nozzle 9 and the bent plate2 is faster than the upper limit value, the printed layer easily receives an influence by an air flow or vibration generated between the nozzle 9 and the bent plate 2. A foreign matter entrapped by the air flow may be mixed to the printed layers 31 to 34 and may cause defects. The printed layers 31 to 34 which do not have desired linear accuracy due to vibration may be formed. Thus, a relative moving speed slower than the upper limit value is preferable. The relative moving speed is more preferably 230 mm/s or slower and further preferably 200 mm/s or slower.
[0115]The lower limit value of the relative moving speed between the nozzle 9 and the bent plate 2 is not particularly limited and is preferably 5 mm/s or faster. The relative moving speed influences a manufacturing time of the plate 1 with a printed layer. If the relative moving speed is the lower limit value or greater, the plate 1 with a printed layer including the printed layers 31 to 34 having high quality can be produced with high production efficiency. The relative moving speed is more preferably 10 mm/s or greater and further preferably 20 mm/s or greater.
[0116]In the present embodiment, as described above, the thicknesses T10, T20, T31 and T41 of the entirety of the left-side printed layer 31, the entirety of the right-side printed layer 32, the upper-side single-layer portion 331, and the lower-side single-layer portion 341, which constitute the lower printed layer 35, are equal to each other. Therefore, the printing conditions (amount of the discharged ink and moving speed of the nozzle 9) thereof are preferably the same.
[0117]On the other hand, the thicknesses T32, T33, T42, and T43 of the first to fourth upper printed layers 332, 333, 342, and 343 are thinner than the left-side printed layer 31 and the like. Thus, the printing conditions thereof are preferably different from those of the left-side printed layer 31 and the like. For example, preferably, the amount of the discharged ink is reduced or the moving speed of the nozzle 9 is increased. That is, when the upper-side printed layer 33 and the lower-side printed layer 34 are printed, the printing conditions when the printing starts and ends are preferably made different from printing conditions during a period therebetween.
[0118]A gap between the nozzle 9 and the bent plate 2 is preferably controlled to be from 0.5 mm to 2 mm. According to this, in the case where the printed layer is formed in a twist structure, the printed layer can be controlled to have a desired thickness range and a uniform printed layer is obtained. In addition, in the case where the plate 1 with a printed layer including the display region 4 as illustrated in FIG. 3 is produced, printing can be performed while high linearity is maintained for the boundary between the printed layer and the display region 4. In the case where printing is performed on the entire surface of the bent plate 2 and a portion such as the display region 4, at which the printed layer is not formed, is not provided, and in the case where uniformity of the thickness is not desired, the gap between the nozzle 9 and the bent plate 2 is not particularly limited.
[0119]Inks when the printed layers 31 to 34 are printed are preferably the same as each other.
[0120]Then, drying and firing may be performed to harden the printed layers 31 to 34. Accordingly, the plate 1 with a printed layer can be obtained. The drying or firing of the printed layers 31 to 34 may be performed every time each of the printed layers 31 to 34 is formed or may be performed after all the printed layers 31 to 34 are formed. That is, it is not particularly limited.
Advantageous Effect of Plate with a Printed Layer
[0121]In any of the case where the inks used for the lower printed layer 35 and the upper printed layers 332, 333, 342, and 343 are the same as each other, and the case of being different from each other, a difference in thickness between the single-layer portions 313, 323, 331, and 341 and the multi-layer portions 361, 362, 363, and 364 occurs. Thus, when the plate 1 wi