Heater plate, heater device including the heater plate, and method for manufacturing the heater plate

Abstract

An improved heater plate (1) is provided herein, comprising a carrier plate (10) having a first main side (11) and a second main side (12) opposite to the first main side. On the first main side (11) of the carrier plate (10), a resistive heating layer (112) is provided, and on the second main side (12), a plurality of bus bars (122) housed in respective V-shaped grooves (121) within the carrier plate (10) are provided. The V-shaped grooves (121) taper inwards towards respective slit-shaped openings (13) in the direction of the first main side (11), and the bus bars (122) are electrically connected to the resistive heating layer (112) through the respective slit-shaped openings (13). Also provided is a method of manufacturing the improved heater plate (1), as well as a heater device comprising the heater plate.

Description

Technical Field

[0001] The present invention relates to a heater plate. The present invention further relates to a heater device comprising a heater plate. The present invention still further relates to a method of manufacturing a heater plate.

Background Art

[0002] International Patent Application No. 2021 / 230746 discloses a transfer method for transferring a viscous functional material onto a receiving substrate. The method provides a plate having a plurality of individually addressable resistive heater elements. In use, the viscous functional material is heated by the resistive heater elements, thereby inducing a vapor pressure at the junction between the functional material and the plate. Thereby, the transfer of the viscous functional material from the plate to the target surface is induced. It is necessary to provide a heater plate that can be manufactured efficiently and a method for efficiently manufacturing the heater plate.

Summary of the Invention

Problems to be Solved by the Invention

[0003] A first object of the present invention is to provide an improved heater plate that can be manufactured efficiently.

[0004] A second object of the present invention is to provide a heater device comprising an improved heater plate.

[0005] A third object of the present invention is to provide an improved method for efficiently manufacturing a heater plate.

Means for Solving the Problems

[0006] The improved heater plate according to the first object comprises a carrier plate having a first main side and a second main side opposite to the first main side. On the first main side of the carrier plate, a resistive heating layer is provided. On the second main side thereof, a plurality of V-shaped grooves are formed in the carrier plate, and respective bus bars are accommodated in these grooves. The V-shaped grooves taper inwardly towards respective slit-shaped openings in the direction of the first main side, and the bus bars therein are electrically connected to the resistive heating layer through the respective slit-shaped openings.

[0007] The improved heater plate can be obtained by using an improved manufacturing method. A carrier plate of a material having anisotropic etching behavior such as silicon is provided inside. The carrier plate has a first main surface on its first main side and a second main surface on the second main side opposite to the first main side.

[0008] The method includes etching a plurality of V-shaped grooves in the second main surface of the carrier plate, and the V-shaped grooves taper inwardly in the direction of the first main side. Due to the anisotropic etching behavior of the material of the carrier plate, the V-shaped grooves can be formed with a clearly defined wall angle in a simple etching process. For example, by using a KOH or TMAH etchant, 1-0-0 oriented silicon is etched along the crystal structure to form a wall angle of 54.74 degrees.

[0009] The formed V-shaped grooves extend towards respective slit-shaped openings in the first main surface.

[0010] This method further includes depositing a resistive heater layer on the first main surface and depositing respective bus bars in the V-shaped grooves. Using this, for each electrical connection, the resistive heater layer is provided through the respective slit-shaped openings in the first main surface.

[0011] In one embodiment, the slit-shaped opening in the first main surface can be formed as part of a process for etching a V-shaped groove. In that case, the etching process is continued until the etchant completely protrudes the carrier plate. In practice, the carrier plate may have different thicknesses. In that case, the slit-shaped openings formed in the first main surface also have various widths. That is, where the carrier plate is relatively thick, the slit formed by this process is relatively narrow compared to where the carrier plate is relatively thin. Thus, an example of this method includes an additional step before the process of etching the V-shaped groove. In this additional step, the thickness profile of the carrier plate is measured, and an etching mask is formed on the second main surface having respective rectangular openings for each of the plurality of V-shaped grooves such that each of the respective rectangular openings has an appropriate width proportional to the thickness of the carrier plate in which the respective V-shaped groove is to be formed. Thereby, it is achieved that the grooves formed by the etching process terminate within slits having the same width. It should be noted that where the thickness of the carrier plate varies in the length direction of the grooves to be formed, the width of the openings can thus vary in a manner proportional to the thickness of the carrier plate in the length direction.

[0012] In another embodiment of this method, the slit-shaped openings in the first major surface are formed in a separate process. This embodiment includes providing each slit-shaped opening in the first major surface by anisotropically etching a slit-shaped groove in the first major surface of the carrier plate. In this embodiment, the plurality of V-shaped grooves are etched to a depth less than the minimum value of the thickness of the carrier plate. In this alternative embodiment, it is not necessary to locally know the exact thickness of the plate. If it is known that the plate varies in thickness between a minimum value Dmin and a maximum value Dmax, the V-shaped grooves can be etched to the same depth Dg that does not exceed the minimum value, and the slit-shaped grooves can be etched to a depth at least equal to the difference between the maximum value Dmax and the depth Dg. Also, in this case, each electrical connection to the resistive heater layer extends to each bus bar in the V-shaped groove via each slit-shaped groove. Note that these processes of etching the V-shaped grooves and the slit-shaped openings can be performed in any order. However, it is preferred to first etch the V-shaped grooves and then use reactive ion etching to etch the slits from the opposite side. It is preferred to anisotropically etch the slits such that the slit width becomes narrower.

[0013] In one embodiment, the plurality of busbars are provided as respective busbar layers that conform to the surfaces of the respective V-shaped grooves. Thereby, for example, using pogo pins, electrical contact between the busbar and the power source can be established in an efficient manner. In the example, the busbar layer is provided with a joint sub-layer of a metal having a low coefficient of thermal expansion on the side facing the carrier plate. The joint sub-layer functions as a joint between the material of the carrier plate and the core of the busbar. Thereby, a highly conductive metal such as copper can be used for the core without being overly restricted by the requirements of the coefficient of thermal expansion. Specifically, in such an example, the resistive heating layer is also formed from the metal having a low coefficient of thermal expansion, and a portion of the joint sub-layer protrudes through each of the slit-shaped openings. By using the same metal having a low coefficient of thermal expansion for both the joint layer and the resistive heating layer, the manufacturing process is simplified.

[0014] In an embodiment, the busbar layer includes a contact sub-layer of a metal having a low contact resistance on the side facing away from the carrier plate. The electrical contact between the busbar and the power source is substantially improved by only a thin sub-layer of the low contact resistance type metal.

[0015] In some embodiments, the resistive heater layer of the heater plate is patterned into a plurality of mutually insulated resistive heater strips extending in a further lateral direction of the plate orthogonal to the lateral direction of the busbar, and one or more of the busbars are interrupted at positions opposite to the positions between successive ones of the heater strips. The interruption in the busbar forms mutually insulated busbar portions. The resistive heater layer can be controlled in pixel units by supplying a drive voltage to a pair of busbar portions in contact with a section of the heater strip, or to a continuous busbar and a busbar portion in contact with a heater strip section.

[0016] In other embodiments, the resistive heater layer of the heater plate is patterned into a plurality of mutually insulated resistive heater segments, and one or more busbars are interrupted at positions opposite to the positions at the boundaries between successive ones of the heater strips. The interruption in the busbar forms mutually insulated busbar portions. The resistive heater layer can be controlled in segment units by supplying a drive voltage to a pair of busbar portions in contact with the resistive layer segments, or to the busbar portions in contact with the continuous busbar and the resistive heater layer segments.

[0017] An improved resolution that can control the heat induction within the heater plate is achieved by embodiments comprising a plurality of longitudinal busbar portions mutually insulated from each other. The plurality of longitudinal busbar portions are as follows: a) Each set of first longitudinal busbar portions formed in each of a first plurality of first busbars of a first polarity extending in a first transverse direction; b) Each set of second longitudinal busbar portions in each of a second plurality of busbars of a first polarity extending in a second transverse direction (y) orthogonal to the first transverse direction, wherein each second busbar portion extends to a central portion between respective busbar portions of successive ones of the first plurality of first busbars; c) Each set of third longitudinal busbar portions formed in each of a third plurality of third busbars of a second polarity opposite to the first polarity, wherein each third busbar extends in the first transverse direction between successive ones of the first plurality of first busbars, and each set of third longitudinal busbar portions comprises respective pairs of third longitudinal busbar portions of at least substantially the same length, which have respective first ends in the vicinity of respective ones of the second longitudinal busbar portions of successive second busbars and respective second ends facing each other. d) Each of a respective set of fourth longitudinal busbar portions formed in each of a plurality of fourth busbars of a second polarity, wherein each fourth busbar extends in a second lateral direction between mutually successive ones of a plurality of second busbars, and each respective set of fourth longitudinal busbar portions comprises a respective pair of fourth longitudinal busbar portions of at least substantially the same length, these having respective first ends in the vicinity of respective ones of the first longitudinal busbar portions of mutually successive first busbars and having respective second ends facing each other.

[0018] In this embodiment having improved resolution, the resistive heater layer comprises respective resistive heater layer segments between a third longitudinal busbar portion directly adjacent to a respective pair of first longitudinal busbar portions and a fourth longitudinal busbar portion directly adjacent to a respective pair of second longitudinal busbar portions. In operation, each resistive heater layer segment can be selectively heated by supplying power to respective pairs of contact pins.

[0019] Typically, the heater plate is provided as a component of a heater device within a printing press. The heater device also comprises a support unit for supporting the heater plate on its second major side, in addition to the heater plate. The support unit comprises respective spring-loaded contact pins, also referred to as pogo pins, for providing electrical contact with respective ones of the busbars. It is attractive if the support unit of the heater device is suitable for combinations with various types of heater plates used by various customers, such as a standard heater plate configured to print a large area at once or in line units, a heater plate suitable for pixel-by-pixel printing, and a high-resolution heater plate enabling printing at four times the resolution. Considering these considerations, a further improved embodiment of the heater plate is constituted by the fact that it comprises a plurality of longitudinal busbar portions insulated from each other, the plurality of longitudinal busbar portions being a) Each of a plurality of first busbars of a first polarity extending in a first transverse direction, each set of first longitudinal busbar portions formed therein; b) Each of a plurality of second busbars of a first polarity extending in a first transverse direction, each set of second longitudinal busbar portions formed therein and extending in a second transverse direction orthogonal to the first transverse direction, wherein a region formed by a pair of mutually successive first busbars and a pair of mutually successive second busbars is defined by each pair of busbar portions of each first busbar of the first busbar pair and each pair of mutually successive second busbars of each second busbar pair, each set of second longitudinal busbar portions defining respective areas; c) Each cross-shaped busbar disposed within each area that divides each area into four quadrants, each quadrant including a respective transverse portion of a resistive heating layer, the resistive heating layer being electrically connected to each branch of the cross-shaped busbar and each one of the busbar portions of the busbars defining the boundary of the area, each cross-shaped busbar.

[0020] In this further improved embodiment of the heater plate, the first busbar portion of a pair of longitudinal busbar portions of the first busbar has an end between two successive busbar portions of the first busbar of a pair of second busbars bounding the area, and the second busbar of the pair of longitudinal busbar portions of the first busbar has an end between a branch of the cross-shaped busbar facing the first busbar and a branch of the cross-shaped busbar in the area directly adjacent to and facing the busbar. This improved heater plate also provides four times the resolution and can be combined with a support unit that is also compatible with a heater plate addressable in standard row units and a heater plate addressable in pixel units.

[0021] These and other aspects are disclosed in more detail with reference to the drawings.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 3C

Figure 3D

Figure 3E

Figure 3F

Figure 3G

Figure 3H

Figure 3I

Figure 3J

Figure 3K

Figure 3L

Figure 4A

Figure 4B

Figure 4C

Figure 5A

Figure 5B

Figure 5C

Figure 6A

Figure 6B

Figure 7A

Figure 7B

Figure 8A

Figure 8B

Figure 9A

Figure 9B

Figure 10A

Figure 10B

Mode for Carrying Out the Invention

[0023] Detailed Description of the Drawings Like reference symbols in the various drawings indicate like elements unless otherwise indicated.

[0024] FIG. 1 schematically shows a heater device comprising a heater plate 1 and a support unit 2 for supporting the heater plate 1. As shown in FIG. 1, the heater plate 1 comprises a carrier plate 10 having a first main side 11 and a second main side 12 opposite the first main side. On the first main side 11, a resistive heating layer 112 is provided on the carrier plate 10. On the second main side 12, a plurality of bus bars 122, 122a, 122b, … are provided, each housed within respective V-shaped grooves 121, 121a, 121b within the carrier plate 10. The V-shaped grooves 121, 121a, 121b.. taper inwards in the direction of the first main side 11 towards respective slit-shaped openings 13, 13a, 13b, and the bus bar 122 is electrically connected to the resistive heating layer 112 through their respective slit-shaped openings 13. The support unit 2 that supports the second main side 12 of the heater plate 1 comprises spring-loaded contact pins 21, 21a, 21b to provide electrical contact with one of each of the bus bars 122, 122a, 122b. In the example shown, the support unit 2 comprises additional support elements 22, 22a, 22b, 22c,.. that do not function to provide electrical contact.

[0025] During operation, a viscous functional material, such as solder, curable conductive ink, or curable electrical insulating ink, is provided on the surface of the first major surface 11 of the heater plate 1, and the heater plate 1 provided with the viscous functional material is disposed opposite to the target surface. In this configuration, one or more sections of the heater plate 1 are heated by supplying power between pairs of contact pins. Thereby, the viscous functional material is heated by the resistive heater layer 112, and thus, a vapor pressure is induced at the joint of the functional material and the plate. The vapor pressure causes the viscous functional material to move from the plate 1 to the target surface. In one embodiment, the additional support elements 22, 22a, 22b, 22c are made of a material with good thermal conductivity to enable rapid cooling of the heater plate 1 after this operation.

[0026] Figure 2 shows a portion of one embodiment of the heater plate 1 in more detail. As shown in Figure 2, the resistive heater layer 112 extends continuously on the first major surface 11 of the carrier plate 10. In the embodiment shown, the resistive heater layer 112 is coated with an insulating layer 113. Thereby, the heater plate 1 is also suitable for printing of conductive functional materials. As shown in Figure 1 for the bus bar 122 and in detail in Figure 2, the plurality of bus bars are provided as respective bus bar layers that conform to the surface of the V-shaped groove 121 in which they are formed. As shown in Figure 2, reliable electrical contact between the bus bars 122, 122a, 122b and the pogo pins 21, 21a, 21b can be established in an efficient manner.

[0027] As shown in more detail in FIG. 2, for the bus bar layer 122, a joint sub-layer 1221 of a metal having a low coefficient of thermal expansion is provided on the side surface of the bus bar layer facing the carrier plate 10. The joint sub-layer 1221 functions as a joint between the material of the carrier plate 10 and the core 1222 of the bus bar. Thereby, a highly conductive metal such as copper can be used for the core without being overly restricted by the requirements of the coefficient of thermal expansion. Suitable for this purpose are metals with a CTE of less than 10 ppm / K, preferably 5 ppm / K or less. Metals such as W, Mo, Cr, Ta are examples thereof. Also, alloys, for example, W90Ti10 having 10% titanium to improve adhesion, are also suitable. Also, in the example shown, the resistive heating layer 112 is formed from the same low CTE metal used for the joint sub-layer 1221 of the bus bar 122, for example, Mo. The electrical interconnection 131 between the bus bar 122 and the resistive heating layer 112 is also formed from the same low CTE metal. This simplifies the manufacturing process in that case such that the electrical interconnection 131 between the bus bar 122 and the resistive heating layer 112 is formed as part of depositing the joint sub-layer 1221.

[0028] In the example shown in FIG. 2, the bus bar layer 122 also includes a contact sub-layer 1224 of a metal having a low contact resistance on the side surface facing away from the carrier plate 10. By using only a thin sub-layer 1224 of a low contact resistance type metal such as Au, the electrical contact between the bus bar and the power supply is substantially improved. Other metals suitable for this purpose are platinum, silver, and other precious metals.

[0029] FIGS. 3A-3L show embodiments of a method for manufacturing the heater plate 1. As shown in FIG. 3A, the carrier plate 10 is provided in step S1 with a material having anisotropic etching behavior. An example thereof may be a 1-0-0 oriented silicon plate having a thickness in the range of about 30 micrometers to about 1000 micrometers. The carrier plate 10 has a first main surface on its first main side 11 and a second main surface on its second main side 12.

[0030] As shown in FIG. 3F, in step S6, on the second main surface of the carrier plate 10, a plurality of V-shaped grooves 121, 121a, 121b,... are etched. The V-shaped grooves taper inwards in the direction towards the first main surface. Due to the anisotropic etching behavior of the carrier plate 10, this can be simply achieved in a wet etching process using an etchant such as KOH or TMAH. As shown in FIG. 3L, in step S12, the resistive heater layer 112 is deposited on the first main surface. The resistive heater layer 112 is preferably a low CTE metal as mentioned above.

[0031] Also, each of the bus bars 122, 122a, 122b... is deposited within the V-shaped grooves 121, 121a, 121b,... and is used to provide respective electrical connections 131 with the resistive heater layer 112 through respective slit-shaped openings 13, 13a, 13b,... within the first main surface. As shown in FIGS. 3H and 3K, this process can be carried out in a plurality of steps. In this example, an aligned sputter mask 105 is used in step S8, and then a low CTE metal sublayer 1221 such as Mo and a seed layer for the sublayer 1222 forming the core of the bus bars 122, 122a, 122b, for example, Cu, are deposited. Then, in subsequent step S11, the sublayer 1222 is deposited on the seed layer by electroplating, and in this case, electroplating of an intermediate layer 1223 of a metal having a low contact resistance such as Au and a sublayer 1224 follows. In this case, the Ni intermediate layer 1223 facilitates the adhesion of the low contact resistance layer 1224.

[0032] In one embodiment, similar to Mo, the low CTE metal sub-layer 1221 has a thickness of about 1500 nm, the Cu sub-layer 1222 forming the core of the bus bar 122 has a thickness of about 20 micrometers, the Ni intermediate sub-layer 1223 has a thickness of about 3 micrometers, and the Au low contact resistance sub-layer 1224 has a thickness of about 500 nm. Alternatively, it may be contemplated to provide a bus bar of entirely low CTE metal. In that case, however, the bus bar would not have such excellent electrical properties.

[0033] In an embodiment of the method shown in FIGS. 3A to 3L, in step S6 of etching the V-shaped grooves, steps S3 to S5 as shown in FIGS. 3C to 3E respectively precede. In step S3, an etching mask layer 102 such as silicon nitride (Si3N4) is deposited on the main surface of the carrier plate. In step S4, the thickness profile of the carrier plate 10 is measured, and in subsequent step S5, an etching mask 103 is provided by photolithographically processing the etching mask layer on the second main surface so that substantially rectangular openings of the plurality of V-shaped grooves 121, 121a, 121b,... are formed. The rectangular openings have an appropriate width proportional to the thickness of the carrier plate 10 where the respective V-shaped grooves 121, 121a, 121b,... are formed. For example, if the thicknesses of the carrier plate 10 measured at the locations where the V-shaped grooves 121, 121a, 121b are to be formed are Dx, Dxa, and Dxb, the widths Wx, Wxa, Wxb of the openings at these locations are c.Dx + d, c.Dxa + d, and c.Dxb + d. Here, c is a constant (2 / tgα) determined by the anisotropic characteristics of the material of the carrier plate 10, and d is the desired width of the slit formed on the first main surface. For example, when the carrier plate is a 1-0-0 silicon wafer, the grooves formed as a result of the etching process taper inward at an angle of 54.74°. By these steps, it is achieved that the grooves formed by the etching process terminate with slits having the same width despite variations in the thickness of the carrier plate. In this example, it is presumed that the thickness of the carrier plate varies only in the direction from left to right in the drawing. In reality, thickness variations can also occur in a direction orthogonal thereto. In that case, the openings in the etching mask 103 do not have an exact rectangular shape, but have a width that varies according to the depth variation in its orthogonal direction. Therefore, the width Wx(x,y) of the openings in the etching mask 103 is equal to c.Dx(x,y)+d, where (x,y) is the position on the second main surface. In an optional step S2, after the carrier plate 10 is provided in S1 and before further steps are executed, an electrically insulating layer is provided on the surface of the carrier plate 10. Optionally, after etching S6, S6A a plurality of V-shaped grooves, an electrically insulating layer is also provided in S7. These steps S2, S7 are advantageous when the carrier plate 10 is not a good electrical insulator. Preferably, the electrically insulating layer has a low thermal conductivity. These optional steps S2, S7, as shown in FIGS. 3B and 3G, are preferably carried out by thermally oxidizing the carrier plate 10. Thermal oxidation efficiently provides electrically insulating layers 101, 104 having a low thermal conductivity.

[0034] FIGS. 4A, 4B, 4C illustrate aspects of another approach that can obtain a slit with a uniform width without requiring a thickness profile measurement S4 as described with reference to 3D. It is sufficient to know only between which boundaries the thickness varies. Also, the width of the openings in the etching mask 103 does not need to be determined very precisely as a function of the position on the carrier plate 10 using step S5 as shown in FIG. 3E. Similar to the approach described earlier, the plate 10 is optionally provided with steps S1 and S3 described in FIGS. 3A and 3C using an intermediate step S2.

[0035] In this case, an edge mask 103, such as that formed within the etching mask layer 102 in step S5A, need only have a rectangular opening of uniform width Wx. As in step S6 shown in FIG. 3F, this alternative approach includes a step S6A of etching a plurality of V-shaped grooves 121, 121a, 121b, .. with an etchant such as KOH or TMAH. However, in contrast to step S6 of FIG. 3F, the grooves are etched to a depth less than the thickness of the carrier plate 10. In a separate step S6B shown in FIG. 4C, the slit-shaped openings 13, 13a, 13b, … in the first major surface are formed by anisotropically etching the first major surface of the carrier plate 10, for example, using a reactive ion etching process. In the example shown, the slit-shaped openings 13, 13a, .. are etched in step S6B following step S6A of etching the V-shaped grooves 121, 121a, while a reversal of these steps is also possible, but the best results are obtained in the order shown in FIGS. 4B and 4C. If it is known that the plate varies in thickness between a minimum value Dmin and a maximum value Dmax, the V-shaped grooves can be etched to the same depth Dg that does not exceed the minimum value, and the slit-shaped grooves can be etched to a depth at least equal to the difference between the maximum value Dmax and the depth Dg. Therefore, the separate step S6B results in a slit of a predetermined width for the electrical connection between the bus bar and the resistive heating layer 112, regardless of the variation in thickness within the plate 10, such that the pattern within the etching mask need not have a width variation that closely corresponds to the variation in the thickness of the plate. The open areas within the etching mask can have substantially the same shape. Minor variations in the width of the open area do not affect the width of the slit.

[0036] Steps S5, S6A, S6B, as described herein, can be successful in step S12 of depositing the resistive heating layer 112 and depositing the bus bar in one or more steps, as described with reference to FIG. 3L.

[0037] Figures 5A, 5B, and 5C show subsequent steps S13, S14, and S15. In step S13 shown in Figure 5A, the heater plate 1 obtained by the first approach, the second approach, or a modification thereof is combined with the support unit 2 to form a heater device. The support unit 2 includes respective spring-loaded contact pins 21 to provide electrical contact with respective ones of the busbars. In step S14 shown in Figure 5B, a patterned layer of a viscous substance 7 such as curable conductive ink is provided on the first major surface 11 of the heater plate 1 by, for example, stencil / screen printing using a printing mask 5 and a doctor blade or squeegee 6. In step S15 shown in Figure 5C, power is provided to the resistive heater layer 112 via the contact pins 21 of the support unit, and using the same, the surface of the resistive heater layer 112 is resistively heated, and using the same, a heat flux in the range of about 50 to about 500 kW / cm 2 and a flux in the range of about 0.2 to about 2 J / cm 2 are induced. Using this, the viscous substances 7, 7a, 7b are transferred to the target surface.

[0038] Figures 6A and 6B show the aspects of the first embodiment of the heater plate 1 in more detail. Figure 6A shows a bottom view of the heater plate, that is, a view of the second major surface 12. Figure 6B shows the section thereof in more detail. In this embodiment, the busbars extend over the full size of the plate. The linear sections of the plate can be heated independently of each other. For example, a linear section can be heated separately by supplying power between a busbar 122L- with a contact pin 21L- and a busbar 122L with a contact pin 21L. Another linear section can be heated separately by supplying power between a busbar 122L with a contact pin 21L and a busbar 122L+ with a contact pin 21L+.

[0039] Figures 7A and 7B show, in a bottom view, an aspect of a second embodiment of the heater plate 1, and Figure 7B shows a section of the heater plate in more detail. In this example, the resistive heater layer 112 is patterned into a plurality of mutually insulated resistive heater strips 112a, … 112k, … 112n that extend in a further lateral direction of the plate orthogonal to the lateral direction of the bus bars 122, 122a, … 122l, … 122m. Also, the bus bars are interrupted at positions opposite to the positions between successive ones of the heater strips. The interruption of the bus bars forms mutually insulated bus bar portions 122lk-, 122lk, 122lk+. In this embodiment, the resistive heater layer can be controlled in pixel units by supplying a drive voltage to a pair of bus bar portions in contact with a section of the heater strip, or to a continuous bus bar and a bus bar portion in contact with a heater strip section.

[0040] Figures 8A and 8B also show, in a bottom view, another embodiment, and Figure 8B shows a section of the heater plate in more detail. In this embodiment of the heater plate 1, the resistive heater layer 112 is patterned into a plurality of mutually insulated resistive heater segments A, B, C, D, E, F, …, and one or more of the bus bars are interrupted at positions opposite to the positions at the boundaries between successive ones of the heater strips. The interruption in the bus bar forms mutually insulated bus bar portions 122lk-, 122lk, 122lk+. The resistive heater layer 112 can be controlled in segment units by supplying a drive voltage to a pair of bus bar portions in contact with a resistive layer segment, or to a continuous bus bar and a bus bar portion in contact with a resistive heater layer segment.

[0041] Figures 9A and 9B show a further embodiment in a bottom view. Figure 9A shows a part of the heater plate, and Figure 9B shows the details thereof. This embodiment of the heater plate comprises a plurality of longitudinally extending bus bar portions mutually insulated from each other. These include first, second, third, and fourth longitudinally extending bus bar portions for each set, as will be described in more detail below.

[0042] Each set of first longitudinal bus bar portions 122bc…, 122dc… is formed in each of a first plurality of first bus bars 122, 122b, 122d, … of a first polarity extending in a first lateral direction (x).

[0043] Each set of second longitudinal bus bar portions 126bb, 126bd, …, 126db, 126dd is also formed in each of a second plurality of bus bars 126, 126b, 126d, … of a first polarity extending in a second lateral direction (y) orthogonal to the first lateral direction. The second bus bar portions each extend at a central position between respective bus bar portions of successive ones of the first plurality of first bus bars.

[0044] Each set of third longitudinal bus bar portions 122cb, 122cc is formed in each of a third plurality of third bus bars 122a, 122c, … of a second polarity opposite to the first polarity. The third bus bars extend in the first lateral direction (x) between successive ones of the first plurality of first bus bars, and each set of third longitudinal bus bar portions comprises respective pairs of third longitudinal bus bar portions of at least substantially the same length, which have respective first ends in the vicinity of respective ones of the second longitudinal bus bar portions of successive second bus bars and respective second ends facing each other.

[0045] Each set of fourth longitudinal busbar portions 126cb, 126cc is formed in each of a plurality of fourth busbars 126a, 126c, … of the second polarity. The fourth busbars extend in a second transverse direction between those of the second plurality of second busbars that follow one another, and each set of fourth longitudinal busbar portions comprises a respective pair of fourth longitudinal busbar portions of at least substantially the same length, these having respective first ends in the vicinity of each of those of the first longitudinal busbar portions of the first busbars that follow one another, and respective second ends that face one another.

[0046] The resistive heater layer comprises respective resistive heater layer segments 112cbx, 112cby, 112ccx, 112dcy between each pair of first longitudinal busbar portions and directly adjacent third longitudinal busbar portions, and between each pair of second longitudinal busbar portions and directly adjacent fourth longitudinal busbar portions.

[0047] In operation, each resistive heater layer segment 112cbx, 112cby, 112ccx, 112dcy can be selectively heated by supplying power to respective pairs of contact pins. For example, the heater layer segment 112ccx can be resistively heated by providing power to a pair of contact pins 21ccy and 21bdy.

[0048] Figures 10A and 10B show a further embodiment in bottom view. Figure 10A shows a part of the heater plate, and Figure 10B shows the details thereof.

[0049] An embodiment of the heater plate 1 as shown in Figures 10A and 10B comprises a plurality of longitudinal busbar portions that are insulated from one another. These include each set of first longitudinal busbar portions and each set of second longitudinal busbar portions.

[0050] Each set of first longitudinal busbar portions is formed in each of a plurality of first busbars 122, 122a, 122b, … of a first polarity extending in a first transverse direction (x).

[0051] Each set of second longitudinal busbar portions is also formed in each of a plurality of second busbars 126, 126a, 126b, … of a first polarity extending in a second transverse direction (y) orthogonal to the first transverse direction (x).

[0052] Regions composed of each four parts formed by a first busbar pair of mutually successive first busbars and a second busbar pair of mutually successive second busbars define respective areas Aaa bounded by mutually successive busbar portions of each pair of first busbars of the first busbar pair 122, 122a and mutually successive second busbar portions of each pair of second busbars of the second busbar pair 126, 126a.

[0053] The heater plate further includes respective cross-shaped busbars 128aa of a second polarity opposite to the first polarity disposed within each area, which divide each area into four quadrants Aaa1, Aaa2, Aaa3, Aaa4.

[0054] Each quadrant includes respective lateral portions of a resistive heating layer electrically connected to respective branches of the cross-shaped busbars and busbar portions 122_2, 126a_2, 122a_1, 126_1 of the busbars 122, 126a, 122a, 126 that define the boundary of the area Aaa.

[0055] Of the pair of longitudinal bus bar portions 122_1, 122_2 of the first bus bar 122, the first bus bar portion 122_1 has an end between two subsequent bus bar portions of the first bus bar portion 126 of the pair of second bus bars bounding the area. The second bus bar portion 122_2 of the pair of longitudinal bus bar portions 122_1, 122_2 of the first bus bar 122 has an end between a branch of the cross-shaped bus bar 128aa facing the first bus bar 122 and a branch of the cross-shaped bus bar in the directly adjacent area facing the bus bar.

[0056] Similar to the embodiments of FIGS. 9A and 9B, the improved heater plates of FIGS. 10A and 10B provide four times higher resolution and, in addition, can be combined with a support unit that is also compatible with both a heater plate addressable in standard row units and a heater plate addressable in pixel units.

[0057] In the claims, the term "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. A single component or other unit may perform the functions of several items recited in the claims. The mere fact that certain measurements are recited within different claims does not indicate that these means cannot be used in combination to advantage. Any reference signs in the claims shall not be construed as limiting the scope.

Description of Reference Signs

[0058] 1 Heater plate 2 Support unit 5 Printing mask 6 Doctor blade or squeegee 7 Viscous substance 10 Carrier plate 11 First main side 12 Second main side 13 Opening 21 Spring load contact pin, pogo pin 22 Support element 102 Etching mask layer 103 Etching mask 112 Resistive heating layer 113 Insulating layer 121 V-shaped groove 122 Bus bar, bus bar layer 131 Electrical interconnection 1221 Junction sub-layer 1222 Core 1223 Intermediate layer 1224 Contact sub-layer 101104 Electrical insulation layer 112cbx, 112cby, 112ccx, 112dcy Resistive heater layer segments A, B, C, D, E, F,... Resistive heater segments Dx, Dxa, Dxb Thickness Wx, Wxa, Wxb Width

Claims

1. A heater plate (1), comprising a carrier plate (10) having a first main side (11) and a second main side (12) opposite to the first main side. On the carrier plate (10), a resistive heating layer (112) is provided on the first main side (11), and on the second main side (12), a plurality of busbars (122) accommodated in respective V-shaped grooves (121) within the carrier plate (10) are provided. The V-shaped grooves (121) taper inwards towards respective slit-shaped openings (13) in the direction of the first main side (11), and the busbars (122) are electrically connected to the resistive heating layer (112) through the respective slit-shaped openings (13).

2. The heater plate (1) according to claim 1, wherein the plurality of busbars (122) are provided as respective busbar layers conforming to the surfaces of the respective V-shaped grooves (121).

3. The heater plate (1) according to claim 2, wherein the busbar layer on the side facing the carrier plate (10) comprises a joint sub-layer (1221) of a metal having a low coefficient of thermal expansion.

4. The heater plate (1) according to claim 3, wherein the resistive heating layer (112) is also formed of the metal having a low coefficient of thermal expansion, and a part of the joint sub-layer (1221) protrudes through the respective slit-shaped openings (13).

5. The heater plate (1) according to any one of claims 1 to 4, wherein the busbar layer on the side facing away from the carrier plate (10) comprises a contact sub-layer (1224) of a metal having a low contact resistance.

6. The resistive heater layer (112) is patterned into a plurality of mutually insulated resistive heater strips (112a,..., 112k,..., 112n) extending in a further transverse direction of the plate orthogonal to the transverse direction of the busbars (122, 122a,... 122l,..., 122m), and one or more of the busbars are interrupted at positions opposite to positions between successive ones of the heater strips. The heater plate (1) according to any one of claims 1 to 5.

7. ​ The resistive heater layer (112) is patterned into a plurality of mutually insulated resistive heater segments (A, B, C, D, E, F,...), and one or more of the bus bars are interrupted at positions opposite to the positions at the boundaries between successive ones of the heater strips. The heater plate (1) according to any one of claims 1 to 5.

8. Comprising a plurality of longitudinally extending bus bar portions mutually insulated from each other, the plurality of longitudinally extending bus bar portions being Each set of first longitudinally extending bus bar portions (122bc..., 122dc...) formed in each of a first plurality of first bus bars (122, 122b, 122d...) extending in a first lateral direction (x) (of a first polarity), Each set of second longitudinally extending bus bar portions (126bb, 126bd,..., 126db, 126dd) in each of a second plurality of bus bars (126, 126b, 126d...) extending in a second lateral direction (y) orthogonal to the first lateral direction (of the first polarity), the second bus bar portions each extending in a central portion between the respective bus bar portions of successive ones of the first plurality of first bus bars. The second longitudinally extending bus bar portions (126bb, 126bd,..., 126db, 126dd), Each set of third longitudinally extending bus bar portions (122cb, 122cc) formed in each of a third plurality of third bus bars (122a, 122c,...) (of a second polarity), each of the third bus bars extending in the first lateral direction (x) between successive ones of the first plurality of first bus bars, each set of third longitudinally extending bus bar portions comprising at least substantially the same length of respective pairs of third longitudinally extending bus bar portions, which have respective first ends in the vicinity of respective ones of the second longitudinally extending bus bar portions of successive second bus bars and respective second ends facing each other. Each set of third longitudinally extending bus bar portions (122cb, 122cc) Each set of fourth longitudinal busbar portions (126cb, 126cc) formed in each of a plurality of fourth busbars (126a, 126c...) of the fourth (of the second polarity), wherein each fourth busbar extends in the second lateral direction between successive ones of the second plurality of second busbars, and each set of fourth longitudinal busbar portions comprises a pair of fourth longitudinal busbar portions of at least substantially the same length, these having respective first ends in the vicinity of respective ones of the first longitudinal busbar portions of successive first busbars and respective second ends facing each other, each set of fourth longitudinal busbar portions (126cb, 126cc); The heater plate (1) according to any one of claims 1 to 5, wherein the resistive heater layer comprises respective resistive heater layer segments (112cbx, 112cby, 112ccx, 112dcy) between respective pairs of first longitudinal busbar portions and directly adjacent third longitudinal busbar portions and between respective pairs of second longitudinal busbar portions and directly adjacent fourth longitudinal busbar portions. Claim 9 Comprising a plurality of longitudinal busbar portions insulated from each other, the plurality of longitudinal busbar portions being Each set of first longitudinal busbar portions formed in each of a plurality of first busbars (122, 122a, 122b,...) of the first (first polarity) extending in a first lateral direction (x); In each of a plurality of second bus bars (126, 126a, 126b, …) of the second polarity, which extend in a second lateral direction (y) orthogonal to the first lateral direction (x), a respective set of second longitudinal bus bar portions formed therein, wherein a region composed of four portions formed by a first bus bar pair of the first bus bars succeeding each other and a second bus bar pair of the second bus bars succeeding each other defines respective areas (Aaa) bounded by respective succeeding bus bar portions of each pair of the first bus bars of the first bus bar pair (122, 122a) and respective succeeding second bus bar portions of each pair of the second bus bars of the second bus bar pair (126, 126a); a respective set of second longitudinal bus bar portions; each area is divided into four quadrants (Aaa1, Aaa2, Aaa3, Aaa4), and each area is provided with a respective cross-shaped bus bar (128aa) disposed therein; each quadrant includes a respective lateral portion of the resistive heating layer, which is electrically connected to respective branches of the cross-shaped bus bar and bus bar portions (122_2, 126a_2, 122a_1, 126_1) of the bus bars (122, 126a, 122a, 126) that define the boundary of the area (Aaa); A first one (122_1) of a pair of longitudinal bus bar portions (122_1, 122_2) of the first bus bar (122) has an end between two succeeding bus bar portions of a first one (126) of the pair of second bus bars that bound the area, and a second one (122_2) of the pair of longitudinal bus bar portions (122_1, 122_2) of the first bus bar (122) has an end between a branch of the cross-shaped bus bar (128aa) facing the first bus bar (122) and a branch of the cross-shaped bus bar in a directly adjacent area facing the bus bar. The heater plate (1) according to any one of claims 1 to 5.

10. A heater device comprising a heater plate (1) according to any one of claims 1 to 9 and a support unit (2) for supporting the heater plate (1) on the second main side (12), wherein the support unit (2) comprises respective spring-loaded contact pins (21) for providing electrical contact with respective ones of the busbars.

11. A method of manufacturing a heater plate, comprising: providing (S1) a carrier plate (10) of a material having anisotropic etching behavior, the carrier plate (10) having a first main surface on its first main side (11) and a second main surface on its second main side (12); etching (S6) a plurality of V-shaped grooves (121, 121a, 121b,...) in the second main surface of the carrier plate (10), the V-shaped grooves tapering inwards in the direction of the first main side (11) towards the first main surface; depositing (S12) a resistive heater layer (112) on the first main surface; depositing (S11) respective busbars (122, 122a, 122b,...) in the V-shaped grooves (121, 121a, 121b,...) and using the same to provide respective electrical connections (131) with the resistive heater layer (112) through respective slit-shaped openings (13, 13a, 13b,...) in the first main surface.

12. The method according to claim 11, further comprising, prior to said etching (S6), measuring (S4) the thickness profile of the carrier plate (10) and providing (S5) an etching mask having respective rectangular openings for the plurality of V-shaped grooves (121, 121a, 121b) to be formed on the second main surface, each of the respective rectangular openings having an appropriate width proportional to the thickness of the carrier plate (10) in which the respective V-shaped grooves (121, 1, 1a, 121b,...) are to be formed.

13. By anisotropically etching slit-shaped grooves (13, 13a, ...) on the first main surface of the carrier plate (10), providing the respective slit-shaped openings (13, 13a, 13b, ...) on the first main surface (S6B); and etching the plurality of V-shaped grooves (121, 121a, 121b, ...) having a depth less than the thickness of the carrier plate (10) (S6A), further including that each electrical connection portion (131) with the resistive heater layer (112) extends to each bus bar (122, 122a, 122b, ...) in the V-shaped grooves (121, 121a, 121b, ...) through the respective slit-shaped grooves. The method according to claim 11.

14. The method according to any one of claims 11 to 13, wherein the plurality of bus bars (122) are deposited as respective bus bar layers conforming to the surfaces of the respective V-shaped grooves (121) (S11).

15. Before performing a further step, an electrical insulator layer is provided on the surface of the carrier plate (10) both after the carrier plate (10) is provided (S1) and subsequent to etching the plurality of V-shaped grooves (S6, S6A) (S7). The method according to any one of claims 11 to 14.

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