Insulating substrate

Abstract

An insulating substrate (100) is provided with: a ceramic base material (10) having a main surface (10a); a plurality of first ribs (20) formed on the main surface; and a glaze layer (30) disposed on the main surface so as to cover the plurality of first ribs. The plurality of first ribs extend in a first direction (DR1) in plan view, and are arranged at intervals in a second direction (DR2) orthogonal to the first direction.

Description

Technical Field

[0001] The present invention relates to an insulating substrate. Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2022-78607 (Patent Document 1) describes a thermal print head. The thermal print head described in Patent Document 1 is formed using an insulating substrate.

[0003] The insulating substrate has a ceramic base material and a glaze layer. The ceramic base material has a main surface. The glaze layer is arranged on the main surface. The glaze layer is formed by applying a glass paste on the main surface and firing the applied paste. Summary of the invention

[0004] When firing the glass paste, the glass paste located on the outer peripheral edge of the main surface is easy to dry. Therefore, the glass paste flows toward the outer peripheral edge of the main surface, causing the glass paste to bulge on the outer peripheral edge of the main surface. As a result, the glaze layer formed by firing the glass paste also bulges on the outer peripheral edge of the main surface (coffee ring phenomenon). The portion of the insulating substrate including the glaze layer formed in the bulge is difficult to use to form a thermal print head, so the number of thermal print heads that can be formed using one insulating substrate is reduced.

[0005] The insulating substrate of the present invention comprises: a ceramic substrate having a main surface; a plurality of first ribs formed on the main surface; and a glaze layer arranged on the main surface in a manner covering the plurality of first ribs. The plurality of first ribs extend in a first direction when viewed from above, and are arranged at intervals in a second direction orthogonal to the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 is a top view of the insulating substrate 100 .

[0007] Figure 2 yes Figure 1 Cross-sectional view at II-II in FIG.

[0008] Figure 3 is a top view of the thermal print head 200 .

[0009] Figure 4 yes Figure 3 Cross-sectional view at IV-IV in FIG.

[0010] Figure 5 yes Figure 3 Cross-sectional view at VV in .

[0011] Figure 6 It is a manufacturing process diagram of the insulating substrate 100 .

[0012] Figure 7 It is a cross-sectional view explaining the rib forming step S2.

[0013] Figure 8 It is a manufacturing process diagram of the thermal print head 200.

[0014] Fig. 9 It is a cross-sectional view explaining the wiring layer forming step S5.

[0015] Fig.10 It is a cross-sectional view for explaining the heating element forming step S7.

[0016] Fig.11 It is a top view of the insulating substrate 100A.

[0017] Fig.12 yes Fig.11 Cross-sectional view at XII-XII in FIG. DETAILED DESCRIPTION

[0018] Embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the same or corresponding parts are given the same reference numerals, and repeated descriptions are omitted.

[0019] (First Embodiment)

[0020] The insulating substrate of the first embodiment will be described. The insulating substrate of the first embodiment is assumed to be an insulating substrate 100 .

[0021] <Structure of Insulating Substrate 100 >

[0022] Hereinafter, the structure of the insulating substrate 100 will be described.

[0023] Figure 1 is a top view of the insulating substrate 100 . Figure 2 yes Figure 1 The cross-sectional view at II-II in FIG. Figure 1 and Figure 2 As shown, the insulating substrate 100 has a ceramic base material 10 , a plurality of ribs 20 , and a glaze layer 30 .

[0024] The ceramic substrate 10 has a main surface 10a and a main surface 10b. The main surface 10a and the main surface 10b are end surfaces in the thickness direction of the ceramic substrate 10. The main surface 10b is the opposite surface of the main surface 10a. The main component of the constituent material of the ceramic substrate 10 is, for example, a ceramic such as alumina (Al2O3). The main component means more than 50% of the components in the constituent material.

[0025] The ribs 20 are formed on the main surface 10a. The ribs 20 extend in the first direction DR1 when viewed from above. When viewed from above, it means the situation when viewed from the main surface 10a side along the normal direction of the main surface 10a. A plurality of ribs 20 are arranged at intervals in the second direction DR2 when viewed from above. The second direction DR2 is a direction orthogonal to the first direction DR1. The interval between two adjacent ribs 20 is, for example, the same interval. The interval between two adjacent ribs 20 is, for example, less than 20 mm. The lower limit of the interval between two adjacent ribs 20 is not particularly limited as long as two ribs 20 can be formed at intervals. The width of the rib 20 in the second direction DR2 is, for example, less than 500 μm. The lower limit of the width of the rib 20 in the second direction DR2 is not particularly limited as long as the rib 20 can be formed.

[0026] The height of the rib 20 is assumed to be a height H. The main component of the constituent material of the rib 20 is, for example, ceramic. The rib 20 is formed, for example, by a sintered body including a plurality of particles. The particles included in the sintered body constituting the rib 20 are ceramic particles. The constituent material of the ceramic particles included in the sintered body may be the same as or different from the constituent material of the ceramic substrate 10. The average particle size of the plurality of particles included in the sintered body is, for example, less than 1 μm. The average particle size of the plurality of particles included in the sintered body can be measured, for example, by a laser diffraction or scattering method.

[0027] The glaze layer 30 is arranged on the main surface 10a in a manner covering the plurality of ribs 20. The main component of the constituent material of the glaze layer 30 is glass. Let the thickness of the glaze layer 30 be thickness T. Thickness T is the distance between the main surface 10a and the surface of the glaze layer 30. The height H is preferably greater than 0.7 times and less than 1.0 times the thickness T. The thickness T is preferably greater than 100 μm, greater than 150 μm, or greater than 200 μm. The thickness T is, for example, less than 300 μm.

[0028] <Structure of Thermal Print Head 200>

[0029] Next, the structure of the thermal print head 200 will be described.

[0030] A thermal print head formed using the insulating substrate 100 is referred to as a thermal print head 200 . Figure 3 is a top view of the thermal print head 200. Figure 3 In the figure, the protective layer 60 is omitted. Figure 4 yes Figure 3 Cross-sectional view at IV-IV in FIG. Figure 5 yes Figure 3 The cross-sectional view at VV in FIG. Figure 3 to Figure 5 As shown, the thermal print head 200 includes an insulating substrate 100 , a wiring layer 40 , a heating element 50 , and a protective layer 60 .

[0031] The wiring layer 40 is disposed on the glaze layer 30. The wiring layer 40 includes a common electrode 41 and a plurality of individual electrodes 42. The main component of the constituent material of the wiring layer 40 is, for example, gold (Au).

[0032] The common electrode 41 includes a strip-shaped portion 41a and a plurality of protrusions 41b. The strip-shaped portion 41a extends in the first direction DR1 when viewed from above. The plurality of protrusions 41b are arranged at intervals in the first direction DR1. The protrusions 41b protrude from the strip-shaped portion 41a in the second direction DR2. The individual electrode 42 includes a front end portion 42a at one end portion. The front end portion 42a extends in the second direction DR2 when viewed from above. The protrusions 41b and the front end portion 42a are alternately arranged in the first direction DR1. The individual electrode 42 includes a bonding pad 42b at the other end portion.

[0033] The thermal print head 200 also has first wiring and second wiring, but they are not shown. The first wiring is mainly arranged on the glaze layer 30 and is electrically connected to the common electrode 41. The second wiring is arranged on the first wiring. The first wiring and the second wiring are formed of a sintered body containing silver (Ag) particles, for example.

[0034] The heating element 50 extends along the first direction DR1 when viewed from above. The heating element 50 is arranged on the glaze layer 30 in a manner overlapping with the protrusion 41b and the front end portion 42a. The heating element 50 is composed of, for example, glass and conductive particles contained in the glass. The conductive particles are formed of, for example, ruthenium oxide (RuO2). The adjacent protrusions 41b and the front end portions 42a are electrically connected to each other through the heating element 50.

[0035] The protective layer 60 is disposed on the glaze layer 30 so as to cover the wiring layer 40, the first wiring, the second wiring, and the heating element 50. An opening 61 is formed in the protective layer 60. The bonding pad 42b is exposed from the opening 61. The main component of the material constituting the protective layer 60 is, for example, glass.

[0036] A fixed potential is applied to the common electrode 41. A potential can be selectively applied to each of the plurality of individual electrodes 42 from the driver IC. Therefore, the heating element 50 connected between the front end 42a of one individual electrode 42 to which a potential is selectively applied and the protrusion 41b adjacent to the front end 42a of the one individual electrode 42 is energized to generate heat. The heat is transferred to the paper, and printing can be performed on the paper.

[0037] <Method of Manufacturing Insulating Substrate 100 >

[0038] Hereinafter, a method for manufacturing the insulating substrate 100 will be described.

[0039] Figure 6 1 is a manufacturing process diagram of the insulating substrate 100. Figure 6As shown, the method for manufacturing the insulating substrate 100 includes a preparation step S1, a rib forming step S2, and a glaze layer forming step S3. The rib forming step S2 is performed after the preparation step S1. The glaze layer forming step S3 is performed after the rib forming step S2.

[0040] In the preparation step S1 , the ceramic base material 10 is prepared. Figure 7 2 is a cross-sectional view illustrating the rib forming step S2. Figure 7 As shown, the rib 20 is formed in the rib forming step S2. In the rib forming step S2, first, a paste containing particles constituting the rib 20 is applied to the main surface 10a, and the paste is dried. The application and drying steps are preferably repeated multiple times. Second, the paste arranged on the main surface 10a is fired. In this way, the rib 20 can be formed. In addition, the height H becomes larger due to the repeated application and drying steps. The above-mentioned application can be performed by printing, or it can be performed using a dispenser.

[0041] In the glaze layer forming step S3, the glaze layer 30 is formed. The glaze layer 30 is formed by applying a paste containing glass on the main surface 10a so as to cover the ribs 20 and firing the applied paste. Figure 1 and Figure 2 The insulating substrate 100 has the structure shown.

[0042] <Method of Manufacturing Thermal Print Head 200>

[0043] Next, a method for manufacturing the thermal print head 200 will be described.

[0044] Figure 8 2 is a manufacturing process diagram of the thermal print head 200. Figure 8 As shown, the manufacturing method of the thermal print head 200 includes a preparation step S4, a wiring layer forming step S5, a first wiring forming step S6, a heating element forming step S7, a second wiring forming step S8, a protective layer forming step S9, and a singulation step S10. The wiring layer forming step S5 is performed after the preparation step S4. The first wiring forming step S6 is performed after the wiring layer forming step S5. The heating element forming step S7 is performed after the first wiring forming step S6. The second wiring forming step S8 is performed after the heating element forming step S7. The protective layer forming step S9 is performed after the second wiring forming step S8. The singulation step S10 is performed after the protective layer forming step S9.

[0045] In the preparation step S4 , the insulating substrate 100 is prepared. Fig. 9 2 is a cross-sectional view for explaining the wiring layer forming step S5. Fig. 9As shown, in the wiring layer forming step S5, the wiring layer 40 is formed. In the wiring layer forming step S5, first, a resinate paste containing the constituent materials of the wiring layer 40 is applied on the glaze layer 30. Second, the metal layer is formed by firing the applied resinate paste. Third, a resist pattern is formed on the metal layer. The resist pattern is formed by applying a photoresist on the metal layer and exposing and developing the applied photoresist. Fourth, the metal layer is etched using the resist pattern as a mask. Thus, the metal layer is patterned to become the wiring layer 40.

[0046] In the first wiring forming step S6, the first wiring is formed by applying a conductive paste containing a plurality of silver particles and firing the applied conductive paste. Fig.10 2 is a cross-sectional view for explaining the heating element forming step S7. Fig.10 As shown, in the heating element forming step S7, the heating element 50 is formed. In the heating element forming step S7, first, a conductive paste containing glass and ruthenium oxide particles is applied. Second, the applied conductive paste is fired to form the heating element 50.

[0047] In the second wiring forming step S8, the second wiring is formed. The second wiring is formed by applying a conductive paste containing a plurality of silver particles and firing the applied conductive paste. In the protective layer forming step S9, the protective layer 60 is formed. The protective layer 60 is formed by applying a paste containing glass and firing the applied paste. In the singulation step S10, for example, by irradiation with a laser, the insulating substrate 100 can be cut along the boundary of the thermal print head 200. In the above manner, a thermal print head having Figure 3 to Figure 5 The structure shown is a plurality of thermal print heads 200.

[0048] <Effects of the insulating substrate 100>

[0049] Next, the effects of the insulating substrate 100 will be described.

[0050] The glaze layer 30 is formed by applying a paste containing glass on the main surface 10a and firing the applied glass. The applied paste is easy to dry on the outer peripheral edge of the main surface 10a, and the paste around the outer peripheral edge flows to the outer peripheral edge. As a result, the glaze layer 30 produces a coffee ring phenomenon on the outer peripheral edge of the main surface 10a. The bulge of such a glaze layer 30 is more significant as the thickness T increases. For example, in the case of forming a glaze layer 30 with a thickness T of 200μm, if there is no rib 20, the bulge height of the glaze layer 30 on the outer peripheral edge of the main surface 10a sometimes exceeds 50μm. It is difficult to form a thermal print head 200 on the bulged portion of the glaze layer 30, and the number of thermal print heads 200 that can be obtained from one insulating substrate 100 is reduced.

[0051] In this regard, since the ribs 20 are formed on the main surface 10a of the insulating substrate 100, the paste applied on the main surface 10a is divided into regions by the ribs 20, and the volume of the paste that causes the coffee ring phenomenon is reduced. As a result, in the insulating substrate 100, it is possible to suppress the bulging of the glaze layer 30 on the outer peripheral edge of the main surface 10a, and further increase the number of thermal print heads 200 obtained from one insulating substrate 100.

[0052] When the height H is too small compared to the thickness T, the applied paste may flow over the rib 20. Therefore, by setting the height H to be 0.7 times or more and less than 1.0 times the thickness T, it is possible to more reliably suppress the bulging of the glaze layer 30. In addition, when the rib 20 is composed of a sintered body containing a plurality of particles, the height H can be easily adjusted by repeatedly applying and drying such a paste containing particles. In addition, when the average particle size of such particles is 1.0 μm or less, the rib 20 can be formed in a highly precise shape.

[0053] (Second Embodiment)

[0054] The insulating substrate of the second embodiment will be described. The insulating substrate of the second embodiment is assumed to be an insulating substrate 100A. Here, mainly the differences from the insulating substrate 100 will be described, and duplicate descriptions will be omitted.

[0055] <Structure of Insulating Substrate 100A>

[0056] Hereinafter, the structure of the insulating substrate 100A will be described.

[0057] Fig.11 It is a top view of the insulating substrate 100A. Fig.12 yes Fig.11 The cross-sectional view at XII-XII in FIG. Fig.11 and Fig.12 As shown, the insulating substrate 100A has a ceramic base material 10, a rib 20, and a glaze layer 30. In this regard, the structure of the insulating substrate 100A is common to that of the insulating substrate 100.

[0058] The insulating substrate 100A also has a plurality of ribs 21. In this regard, the structure of the insulating substrate 100A is different from that of the insulating substrate 100. The ribs 21 extend along the second direction DR2 when viewed from above. That is, the ribs 21 intersect with the ribs 20 when viewed from above. The plurality of ribs 21 are arranged in the first direction DR1 at intervals when viewed from above. Except for the extension direction and the arrangement direction when viewed from above, the structure of the ribs 21 is the same as that of the ribs 20. The interval between two adjacent ribs 21 is, for example, less than 20 mm. The lower limit of the interval between two adjacent ribs 21 is not particularly limited as long as two ribs 21 can be formed at intervals. The width of the rib 21 in the first direction DR1 is, for example, less than 500 μm. The lower limit of the width of the rib 21 in the first direction DR1 is not particularly limited as long as the rib 21 can be formed.

[0059] <Method of Manufacturing Insulating Substrate 100A>

[0060] Hereinafter, a method for manufacturing the insulating substrate 100A will be described.

[0061] The method for manufacturing the insulating substrate 100A is the same as the method for manufacturing the insulating substrate 100 in that it has a preparation step S1, a rib forming step S2, and a glaze layer forming step S3. The method for manufacturing the insulating substrate 100A is different from the method for manufacturing the insulating substrate 100 in that in the rib forming step S2, the ribs 21 are formed in the same manner as the ribs 20.

[0062] <Effects of Insulating Substrate 100A>

[0063] The effects of the insulating substrate 100A will be described below.

[0064] In the insulating substrate 100A, the ribs 21 are formed on the main surface 10a in addition to the ribs 20. Therefore, in the insulating substrate 100A, not only the flow of the paste along the second direction DR2 but also the flow of the paste along the first direction DR1 can be suppressed, so that the bulging of the glaze layer 30 on the outer peripheral edge of the main surface 10a can be further suppressed.

[0065] (Note)

[0066] The embodiments of the present invention include the following structures.

[0067] <Note 1>

[0068] An insulating substrate, comprising:

[0069] a ceramic substrate having a major surface;

[0070] a plurality of first ribs formed on the main surface; and

[0071] a glaze layer disposed on the main surface so as to cover the plurality of first ribs,

[0072] The plurality of first ribs extend in a first direction in a plan view, and are arranged at intervals in a second direction orthogonal to the first direction.

[0073] <Note 2>

[0074] The insulating substrate as described in Supplementary Note 1, wherein

[0075] The thickness of the glaze layer is greater than or equal to 0.7 times and less than 1.0 times the height of each of the plurality of first ribs.

[0076] <Note 3>

[0077] The insulating substrate as described in Supplement 1 or 2, wherein

[0078] The thickness of the glaze layer is greater than 100 μm.

[0079] <Note 4>

[0080] The insulating substrate according to any one of Supplementary Notes 1 to 3, wherein

[0081] Also includes a plurality of second ribs formed on the main surface,

[0082] The plurality of second ribs extend along the second direction in a plan view and are arranged at intervals in the first direction.

[0083] The glaze layer also covers the plurality of second ribs.

[0084] <Note 5>

[0085] The insulating substrate according to any one of Supplementary Notes 1 to 4, wherein

[0086] The constituent material of each of the plurality of first ribs is a sintered body including a plurality of particles.

[0087] <Note 6>

[0088] The insulating substrate as described in Supplementary Note 5, wherein

[0089] The average particle size of the plurality of particles is 1.0 μm or less.

[0090] The embodiments of the present invention are described above, but it should be considered that the embodiments of this specification are illustrative in all aspects, rather than limiting the present invention. The scope of the present invention is represented by the part of the invention content, including all changes within the invention content and its equivalent scope.

Claims

1. An insulating substrate, characterized in that: include: a ceramic substrate having a major surface; a plurality of first ribs formed on the main surface; and a glaze layer disposed on the main surface so as to cover the plurality of first ribs, The plurality of first ribs extend in a first direction in a plan view, and are arranged at intervals in a second direction orthogonal to the first direction.

2. The insulating substrate according to claim 1, wherein: The thickness of the glaze layer is greater than or equal to 0.7 times and less than 1.0 times the height of each of the plurality of first ribs.

3. The insulating substrate according to claim 1 or 2, characterized in that: The thickness of the glaze layer is greater than 100 μm.

4. The insulating substrate according to any one of claims 1 to 3, characterized in that: Also includes a plurality of second ribs formed on the main surface, The plurality of second ribs extend along the second direction in a plan view and are arranged at intervals in the first direction. The glaze layer also covers the plurality of second ribs.

5. The insulating substrate according to any one of claims 1 to 4, characterized in that: The constituent material of each of the plurality of first ribs is a sintered body including a plurality of particles.

6. The insulating substrate according to claim 5, wherein: The average particle size of the plurality of particles is 1.0 μm or less.

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