Circuit structure and electronic paper display module
By forming annular protrusions on the substrate surface and then stacking a surface improvement layer, the flatness problem caused by drilling is solved, achieving high flatness of the circuit structure and compatibility with subsequent manufacturing processes.
Patent Information
- Application Number
- CN202520706359.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2026-02-24
- Estimated Expiration
- 2035-04-15
AI Technical Summary
In the existing technology, the drilling process results in poor surface flatness of the substrate of the electronic paper display module, which affects the fit of subsequent processes, and the grinding and thinning process damages the performance of the substrate.
After drilling, at least one surface improvement layer is stacked on the substrate surface to form an annular raised portion, thereby eliminating the height difference caused by the annular raised portion and the electrode and improving the surface flatness.
The surface flatness of the circuit structure is improved without damaging the substrate properties, ensuring the smooth progress of subsequent processes and avoiding the impact of the surface improvement layer on metallized holes and electrode interconnects.
Smart Images
Figure CN223941200U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of electronic additive manufacturing technology, and in particular relates to a circuit structure and an electronic paper display module. Background Technology
[0002] Electronic paper is a technology that uses an array of substrates to drive electronic ink to achieve black-and-white or color display. Due to its extremely low power consumption and ease of reading for the human eye, it has gradually attracted attention. To promote paperless technology, electronic signage, such as electrophoretic displays (EPDs) or electronic paper displays, can replace traditional printed signage. Electronic signage is not only lightweight and thin but also flexible, and has therefore been rapidly adopted in fields such as electronic tags, billboards, flashcards, digital name tags, digital table signs, subway handrails, and digital currency.
[0003] Currently, the backplane for driving electronic paper displays is a double-sided circuit board structure. Electrodes on both sides of the substrate are interconnected through metallized holes that penetrate both sides of the substrate. In the traditional process of making metallized holes, it is necessary to first drill holes in the substrate. However, due to the limitations of the substrate properties and drilling process, it is easy to form raised defects around the through holes, affecting the flatness of the entire substrate surface. This makes it difficult to fit with post-processing processes such as surface coating. It is necessary to make the surface flat by grinding and thinning the entire substrate after drilling. This process damages the surface properties of the substrate and easily reduces the stability of the printing paste on it. Utility Model Content
[0004] In view of this, one objective of this utility model is to propose a circuit structure to solve the problem of poor flatness caused by drilling process defects in the prior art.
[0005] In some illustrative embodiments, the circuit structure includes: a substrate, metallized vias penetrating opposite sides of the substrate, an annular protrusion formed on at least one surface of the substrate surrounding the metallized vias, a first electrode and a second electrode formed on opposite sides of the substrate, the first electrode and the second electrode being interconnected through the metallized vias; wherein the first electrode and / or the second electrode extend on the surface of the annular protrusion on the same side and cross the annular protrusion to connect with the metallized vias; at least one surface improvement layer is stacked on the surface of the substrate having the annular protrusion to eliminate the height difference on that side, either locally or entirely, caused by the annular protrusion and the corresponding electrode.
[0006] Another objective of this invention is to propose an electronic paper display module to solve the problem of poor flatness caused by drilling process defects in the prior art.
[0007] In some illustrative embodiments, the electronic paper display module includes: a substrate having a first surface and a second surface vertically opposite each other; a metallized hole penetrating the first and second surfaces of the substrate, wherein an annular protrusion is formed on the second surface of the substrate surrounding the metallized hole; a display electrode formed on the first surface of the substrate and a driving electrode formed on the second surface of the substrate, the display electrode and the driving electrode being interconnected through the metallized hole; wherein the driving electrode extends across the surface of the annular protrusion and connects to the metallized hole; a portion of the driving electrode serves as an external finger, and a finger region is formed on the substrate; at least one surface improvement layer is stacked on the non-finger region of the second surface of the substrate to eliminate the local height difference caused by the annular protrusion and the driving electrode on that side.
[0008] In some alternative embodiments, the electronic paper display module further includes a functional thin film covering the outside of the surface improvement layer.
[0009] In some alternative embodiments, the metallized hole is a conductive hole or conductive pillar formed by plugging the hole with conductive paste, or the metallized hole is a conductive hole formed by electroplating or chemical plating processes.
[0010] In some alternative embodiments, the display electrode and / or the driving electrode are printed electrodes formed of conductive paste.
[0011] In some alternative embodiments, the at least one surface improvement layer is formed by printing and stacking insulating ink layer by layer.
[0012] In some alternative embodiments, the annular protrusion includes burrs and / or spatter generated from drilling into the substrate.
[0013] In some alternative embodiments, the substrate is a flexible substrate.
[0014] In some optional embodiments, the electronic paper display module further includes an electrophoretic display layer disposed on the display electrode.
[0015] In some alternative embodiments, at least two surface improvement layers are stacked on the second surface of the substrate in the non-finger region to eliminate the height difference on that side caused by the annular ridge and the driving electrode.
[0016] Compared with the prior art, this application has the following advantages:
[0017] This invention achieves surface smoothing without grinding or thinning, ensuring the substrate surface performance remains intact. By stacking at least one surface improvement layer on the substrate surface with the annular protrusions after the electrodes and metallized vias are fabricated, the unevenness caused by the annular protrusions and corresponding electrodes on that side, either locally or entirely, is eliminated. This improves the surface smoothness of the circuit structure, making it compatible with subsequent manufacturing processes. Furthermore, since the surface improvement layer is formed after the electrodes and metallized vias, it also avoids any impact on the metallized via process or the conductive interconnection between the metallized vias and electrodes. Attached Figure Description
[0018] Figure 1 This is a structural example of the circuit structure in the embodiments of this utility model;
[0019] Figure 2 This is a structural example of the electronic paper display module in this utility model embodiment;
[0020] Figure 3 This is a structural example of the electronic paper display module in this embodiment of the present invention, shown in section AA. Detailed Implementation
[0021] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0022] It should be noted that, where there is no conflict, the various technical features in the embodiments of this utility model can be combined with each other.
[0023] This utility model discloses a circuit structure, specifically, as shown in the embodiment. Figure 1 As shown, Figure 1This is a structural example of a circuit structure in an embodiment of the present invention; the circuit structure includes: a substrate 10, metallized holes 40 penetrating opposite sides of the substrate 10, an annular protrusion 30 formed on at least one side surface of the substrate surrounding the metallized holes 40, a first electrode 50 and a second electrode 60 respectively formed on opposite sides of the substrate 10, the first electrode 50 and the second electrode 60 being interconnected through the metallized holes 40; wherein, the first electrode 50 and / or the second electrode 60 extend on the surface of the annular protrusion 30 on the same side and cross the annular protrusion 30 to connect with the metallized holes 40; at least one surface improvement layer 70 is stacked on the surface of the substrate 10 having the annular protrusion 30 to eliminate the height difference caused by the annular protrusion 30 and the corresponding electrode on that side locally or entirely.
[0024] This invention achieves surface smoothing without grinding or thinning, ensuring the substrate surface performance remains intact. By stacking at least one surface improvement layer on the substrate surface with annular protrusions after the electrodes and metallized vias are fabricated, it eliminates height differences caused by these protrusions on that side, either locally or entirely, and even resolves height differences caused by the corresponding electrodes. This improves the surface smoothness of the circuit structure, making it compatible with subsequent manufacturing processes. Furthermore, since the surface improvement layer is formed after the electrodes and metallized vias, it also avoids the impact of the surface improvement layer's formation on the metallized via process and the conductive interconnection between the metallized vias and electrodes.
[0025] The substrate in this embodiment of the utility model can be a rigid board or a flexible board (flexible substrate). Rigid boards include, but are not limited to: FR-4, CEM-1, 22F, CEM-3, wood, glass, plastic, PMMA (acrylic), etc.; flexible boards include, but are not limited to: PET, PVC, PU, PC, PP, PA, PI, CPI (transparent PI), TPE, TPU, TPV, etc.
[0026] In this embodiment of the utility model, there is no explicit limitation on the thickness range of the substrate. The thickness range is sufficient to meet the product performance requirements, and is usually between 0.1 and 500 μm, including but not limited to 0.1 μm, 10 μm, 20 μm, 30 μm, 40 μm, 50 μm, 100 μm, 200 μm, 250 μm, 300 μm, 400 μm, and 500 μm.
[0027] The thickness range of the first electrode and / or the second electrode in this embodiment of the present invention is 0.1 to 100 μm, and can be selected according to product performance requirements or process requirements, including but not limited to 0.1 μm, 1 μm, 2 μm, 3 μm, 4 μm, 5 μm, 6 μm, 7 μm, 8 μm, 9 μm, 10 μm, 15 μm, 20 μm, 30 μm, 40 μm, 60 μm, 80 μm, and 100 μm.
[0028] In this embodiment of the present invention, the first electrode and the second electrode are in a one-to-one correspondence, that is, each first electrode is electrically connected to its corresponding second electrode through a metallized hole; in the case of multiple first electrodes, the first electrodes are independent of each other on the first surface of the substrate and are not directly electrically connected to each other, and each first electrode is electrically connected to its corresponding second electrode, but there is no restriction on whether the second electrodes are independent of each other or interconnected.
[0029] For example, the circuit structure includes three first electrodes and three second electrodes, with one-to-one correspondence between the first electrodes and the second electrodes (electrically connected through corresponding metallized vias); wherein each first electrode is independent of the others, and each second electrode is independent of the others.
[0030] For example, the circuit structure includes: three first electrodes and three second electrodes, with one-to-one correspondence between the first electrodes and the second electrodes (electrically connected through corresponding metallized vias); wherein each first electrode is independent of the others, and two of the three second electrodes are interconnected, with these two interconnected second electrodes being independent of the other second electrode.
[0031] In this embodiment of the invention, the first electrode and / or the second electrode can be directly patterned on the substrate using conductive paste through a printing process.
[0032] The conductive paste in this embodiment of the invention can be a low-temperature conductive paste with resin as the binder phase, or a high-temperature conductive paste with glass frit as the binder phase. For example, this embodiment of the invention uses a low-temperature conductive paste, which, compared to a high-temperature conductive paste, has the advantages of simpler processing, lower curing temperature, and a wider range of substrate options.
[0033] The low-temperature conductive slurry in this embodiment mainly includes resin and conductive filler; wherein, the conductive filler is not limited to one or more of gold, silver, copper, iron, nickel, zinc, aluminum, palladium, conductive carbon black, and graphene.
[0034] In other embodiments of this invention, the first electrode and / or the second electrode can also be implemented using copper plating processes such as sputtering, electroless plating, or electroplating. The copper plating process is not limited to one or more metals selected from copper, gold, nickel, aluminum, zinc, and silver.
[0035] In some embodiments of the present invention, the metallized holes can be conductive holes or conductive pillars formed by plugging with conductive paste. For conductive hole structures, a conductive layer can be formed on the hole wall using a conductive paste plugging process, while for conductive pillars, a solid conductive pillar can be directly formed inside the hole using a conductive paste plugging process. The conductive paste can be the aforementioned low-temperature conductive paste.
[0036] In some other embodiments of this invention, the metallized holes may also be conductive holes formed by electroplating or chemical plating processes.
[0037] In this embodiment of the invention, the surface improvement layer, consisting of at least one layer, is formed by stacking insulating ink through at least one layer-by-layer printing. Specifically, the number of stacked surface improvement layers is not limited to 1, 2, 3, or 5 layers, and this invention does not impose such limitations. Preferably, the surface improvement layer in this embodiment includes at least two stacked layers. Multiple printings of small amounts of insulating ink each time further improve the surface smoothness of the final outer surface, and the printing of small amounts of insulating ink does not cause printing overflow.
[0038] In this embodiment of the invention, the surface improvement layer at least covers the area of the metallized hole, and is mainly used to improve the flatness of local areas. In some embodiments, the surface improvement layer can cover the entire surface. In other embodiments, it can be applied only to local areas, such as a portion of the second electrode used as an external finger. Thus, the corresponding area serves as a finger area in the entire circuit structure for connecting external interconnects. Therefore, the surface improvement layer avoids the electrode in that area to prevent it from being covered or blocked. At the same time, the finger area does not require subsequent processes such as coating.
[0039] The annular protrusions in this embodiment mainly include burrs and / or spatter generated during drilling of the substrate (e.g., mechanical drilling or laser drilling). Typically, the annular protrusions are formed primarily on the surface of the substrate subjected to drilling (i.e., the side closest to the drilling device). The annular protrusions formed by burrs and / or spatter are not uniform annular structures and may exhibit random variations such as breakpoints and height differences. Those skilled in the art should understand that the circuit structure of this embodiment is also applicable to annular protrusions intentionally created by other factors.
[0040] Preferably, in the embodiments of this utility model, the metallized hole, the first electrode, and the second electrode can all be formed by conductive paste; wherein, the first electrode / second electrode adopts a low-temperature conductive paste, and the resin component as the binder phase can also be firmly attached to the surface of the annular protrusion.
[0041] The circuit structure in this embodiment is particularly suitable for electronic paper display modules.
[0042] This utility model embodiment discloses an electronic paper display module (also known as an electronic paper display module driver backplane), specifically, as follows: Figure 2-3 As shown, Figure 2 This is a structural example of the electronic paper display module in this utility model embodiment; Figure 3This is a cross-sectional view AA, illustrating the structure of an electronic paper display module according to an embodiment of the present invention. The electronic paper display module includes: a substrate 10 having a first surface and a second surface vertically opposite each other; a metallized hole 40 penetrating the first and second surfaces of the substrate 10; an annular protrusion 30 formed on the second surface of the substrate surrounding the metallized hole 40; a display electrode 50 formed on the first surface of the substrate 10 and a driving electrode 60 formed on the second surface of the substrate, the display electrode 50 and the driving electrode 60 being interconnected through the metallized hole 40; wherein the driving electrode 60 extends across the surface of the annular protrusion 30 and connects to the metallized hole 40; a portion of the driving electrode 60 serves as an external finger, and a finger region is formed on the substrate 10; at least one surface improvement layer 70 is stacked on the non-finger region of the second surface of the substrate 10 to eliminate the local height difference caused by the annular protrusion and the driving electrode on that side.
[0043] In some embodiments, the electronic paper display module of this utility model may further include a functional film 90 covering the outer side of the surface improvement layer 70. This functional film is not limited to functions such as encapsulation, waterproofing, or oxygen barrier.
[0044] In some embodiments, the electronic paper display module of this utility model may further include an electrophoretic display layer 80 (also known as an E-Ink layer) disposed on the display electrode 50. The area where the electrophoretic display layer 80 overlaps with the display electrode 50 can undergo pattern changes under the drive of the display electrode 50.
[0045] In some embodiments, at least two surface improvement layers 70 are stacked on the non-finger region of the second surface of the substrate 10 to eliminate the height difference on that side caused by the annular ridge 3 and the drive electrode 60.
[0046] In this embodiment of the invention, the through hole 20 of the substrate 10 in the electronic paper display module can be drilled on the second surface of the substrate, thereby forming an annular protrusion 30 on the second surface of the substrate 10, ensuring that the first surface of the substrate 10 is not affected by the annular protrusion 30, and avoiding affecting the tight bonding between the display electrode 50 and the electrophoretic display layer 80.
[0047] The material selection, structure, and parameters of the electronic paper display module in this embodiment can refer to the circuit structure described above; wherein, the display electrode of the electronic paper display module in this embodiment can correspond to the first electrode of the circuit structure described above, and the driving electrode can correspond to the second electrode of the circuit structure described above.
[0048] This utility model discloses a method for manufacturing an electronic paper display module, which may include:
[0049] Step S11: Provide a substrate 10;
[0050] Step S12: A through hole 20 is formed on the substrate 10 by mechanical or laser drilling process, and an annular raised portion 30 is formed around the through hole on the drilling surface (the side of the substrate close to the drilling device, i.e. the second surface mentioned above).
[0051] Step S13: Use conductive paste to plug the through hole 20 to obtain metallized hole 40;
[0052] Step S14: A display electrode 50 is formed on the first surface of the substrate 10 and a driving electrode 60 is formed on the second surface using conductive paste; the display electrode 50 and the driving electrode 60 are electrically interconnected through metallized holes 40.
[0053] In this embodiment, a portion of the driving electrode 60 covers the annular protrusion 30 (crossing the annular protrusion) and is connected to the metallized hole 40 surrounded by the annular protrusion 30; the portion of the driving electrode 60 serves as an external finger and forms a finger region on the substrate.
[0054] Step S15: Using insulating ink, a surface improvement layer 70 is formed on the non-finger area of the second surface of the substrate 10 to cover the driving electrode 60 in the non-finger area.
[0055] Step S16: Apply a functional thin film 90 to the surface improvement layer 70 and deposit an electrophoretic display layer 80 on the display electrode 0.
[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.
Claims
1. A circuit structure, characterized in that, include: The substrate comprises a metallized hole penetrating opposite sides of the substrate, an annular protrusion formed on at least one side surface of the substrate surrounding the metallized hole, a first electrode and a second electrode formed on opposite sides of the substrate, the first electrode and the second electrode being interconnected through the metallized hole; wherein the first electrode and / or the second electrode extend on the surface of the annular protrusion on the same side and cross the annular protrusion to connect with the metallized hole; at least one surface improvement layer is stacked on the surface of the substrate having the annular protrusion to eliminate the height difference on that side, either locally or entirely, caused by the annular protrusion and the corresponding electrode.
2. An electronic paper display module, characterized in that, include: The substrate has a first surface and a second surface that are vertically opposite each other; A metallized hole penetrates the first and second surfaces of the substrate, and an annular ridge is formed on the second surface of the substrate surrounding the metallized hole; A display electrode is formed on a first surface of the substrate and a driving electrode is formed on a second surface of the substrate, the display electrode and the driving electrode being interconnected through the metallized hole; wherein the driving electrode extends on the surface of the annular protrusion and crosses the annular protrusion to connect with the metallized hole; a portion of the driving electrode serves as an external finger, and a finger region is formed on the substrate; At least one surface improvement layer is stacked on the second surface of the substrate in the area outside the finger to eliminate the height difference on that side caused by the annular ridge and the driving electrode.
3. The electronic paper display module according to claim 2, characterized in that, Also includes: A functional thin film covering the outside of the surface improvement layer.
4. The electronic paper display module according to claim 2, characterized in that, The metallized hole is a conductive hole or conductive pillar formed by plugging the hole with conductive paste, or the metallized hole is a conductive hole formed by electroplating or chemical plating process.
5. The electronic paper display module according to claim 2, characterized in that, The display electrode and / or the driving electrode are printed electrodes formed from conductive paste.
6. The electronic paper display module according to claim 2, characterized in that, The at least one surface improvement layer is formed by printing and stacking insulating ink layer by layer.
7. The electronic paper display module according to claim 2, characterized in that, The annular protrusion includes the curled edges and / or spatter generated from drilling into the substrate.
8. The electronic paper display module according to claim 2, characterized in that, The substrate is a flexible substrate.
9. The electronic paper display module according to claim 2, characterized in that, Also includes: An electrophoretic display layer is disposed on the display electrode.
10. The electronic paper display module according to claim 2, characterized in that, At least two surface improvement layers are stacked on the second surface of the substrate, in the area outside the finger, to eliminate the height difference on that side caused by the annular ridge and the driving electrode.