201107151 六、發明說明： 【發明所屬之技術領域】 本發明涉及一種網印模版，其具有包含第一缺口的第— 網印模版層和包含第二缺口的第二網印模版層，從而印刷 介質能夠從所述第一網印模版層的頂面穿過所述第—缺口 和所述第二缺口朝向能夠佈置在它們下方的基板的方向輪 送。 Ο 【先前技術】 在網印時或者在漏印方法中將印刷介質施加至網印模 版，隨後利用沿網印模版頂面導向移動或者緊靠該頂面導 向移動的刮板將印刷介質送入該網印模版的缺口。通過刮 板一次或多次的運動能夠將印刷介質朝向底面方向輸送並 〇且到達設置於其下的基板。印刷介質不能到達由網印模版 覆蓋的區域，從而在基板上形成印刷圖案（Druckbild )， 該印刷圖案基本對應於該網印模版的缺口。 網印和網印模版的採用是早已已知的並且是經過了實 踐檢驗的。然而如果在網印模版中的缺口的尺寸較小，就 會造成刮板在承受相對較大的力的情況下擠壓網印模版， 以使印刷介質也可以被輸送至底面並且不會在去那裏的路 上枯附在這些小缺口卜這種較纟壓力是有缺點的，這是 因為這縮短了網印模版的使用壽命，並且網印模版精密加 201107151 工的頂面的磨損也相對較快。 . 如果在漏印印刷介質之後從基板去除網印模版，那麼在 *小缺口情況下尤其會出現印刷介質粘附在網印模版上並且 不枯附在基板上的情況。這樣，基板上就缺少印刷介質。 反之’如果印刷介質粘附在基板上（如所規定的那樣）， 那麼一部分印刷介質仍然會保留在這些缺口中。由此導致 在基板上的印刷區域的層厚各有不同。 〇 此外，基於網印模版載體（例如織物）的遮蔽也會出現 層厚各有不同。與在交叉點處相比，在織物開口的位置處 有更多的印刷介質穿過模版。在印刷介質粘度較高情況下 (其中，介質不會沿側向流動），印跡（Druckauftrag)的 厚度型廓（H0henpr0fU )具有顯著的高度差。 【發明内容】 本發明的目的因此在於提供—種網印模版利用所述網 U印模版在缺口較小情況下在基板上獲得可靠的印跡，所述 網印模版比以前的模版的耐用度更高，並且在基板上相對 較寬地塗覆印刷介質時也可以得到均勻的層厚/ 該目的通過獨立請求項的榡的得到解決。本發明的有利 改進方式是附屬請求項的標的。 本發明涉及一種網印模版’其具有包含第-頂面和第一 底面的第一網印模版層，其中 具中，所述模版具有第—缺口， 所述第一缺口從所述頂面貫通 貝逋至所述底面，其中，所述第 201107151 ❹ 一缺口在所述第一頂面上具有印刷介質入口而在所述第 -底面上具有印刷介質出口，其中，所述人口的面積在垂 直於所述面積投影時最多在局部與所述出口的面積重叠， 其中，所述網印模版具有包含第二頂面和第二底面的第二 網印模版層’纟中，所述第二網印模版層的所述第二頂面 與所述第-網印模版層的所述第—底面連接，《中，所述 第-網印模版層具有第二缺π，&而印刷介質能夠從所述 第一網印模版層的所述頂面穿過所述第一缺口和所述第二 缺口輸送至能夠佈置在它們下方的基板上。 在網印模版的這種構造方式中，所述印刷介質不僅被正 交地或者說垂直於所述網印模版的所述頂面地送入缺口， 而且也可以朝向偏離法線的方向輸送。這簡化了印刷介質 朝向基板方向的輸送，從而通過刮板以較小的力消耗就可 以將印刷介質輸送穿過缺口。因而可以獲得網印模版的較 高耐用度。根據本發明的一個實施方式，所述第一缺口的 〇壁在所述出口範圍内關於所述網印模版的所述第一底面在 大於0。且小於90。的角度範圍内取向。因而形成“分離棱 邊（Abreiflkante) ’’ ，其使得能夠以確定方式剪斷印刷介 質’並且避免了印刷介質完全粘附在第一缺口中。 特別有利的是，所述第一缺口的壁在其入口和出口之間 關於所述第一網印模版層的所述底面在大於〇。且小於9〇。 的角度範圍内取向。因而存在相對底面傾斜的第一缺口， 從而在刮板運動時存在優選方向，在該優選方向的情況下 印刷介質可以特別容易地被送入第一缺口。在該實施方式 201107151 中也存在分離棱邊。 如果所述第-缺口的橫截面在其入口和出口之間是不 規則的Μ如疋縮小的，那麼進—步增強了對印刷介質的 剪斷。 根據本發明的另一實施方式，這些缺口中的至少一個設 有塗層。所述塗層縮小了印刷介質的通過面積，並且使得 印跡具有更小的尺寸，其中，所述塗層具有一個厚度，所 〇述厚度至少為所述缺口的最小橫截面寬度的5%，並且所述 塗層對水的接觸角在0。至90。的範圍内。 接觸角是固體材料的表面上的液滴相對該表面形成的 角度。因此，在0至90。範圍内的接觸角的情況下，液態 或者膏狀的印刷介質相對塗層表面形成較好的相互作用， 從而¥從承印基板去除網印模版時，大部分的印刷介質保 持粘附在以這種方式塗覆的缺口中。這由於分離棱邊的作 用被進一步簡化，從而可以印製均勻的層厚，而不會有過 Ο多材料從頂面的缺口一起印刷至基板上。 根據本發明的另一實施方式，缺口設有塗層，從而塗層 縮小了印刷介質的通過面積並且使得印跡具有更小的尺 寸’其中’所述塗層具有一個厚度，所述厚度至少為所述 缺口的最小橫截面寬度的5%，並且所述塗層對水的接觸角 在從大於90至150。的範圍内。在此僅形成印刷介質的相 對塗層表面的很小的相互作用。印刷介質能夠以更小的阻 力送入缺口。此外在印刷介質被漏印、且從基板去除網印 模版之後’能夠以很小的成本去除保留在缺口中的印刷介 201107151 質。當從基板去除網印模版時，送入缺口的印刷介質僅一 小部分保留在該缺口中。結果，印跡具有可以與網印模版 • 的厚度相等的厚度。 所述第一網印模版層和所述第二網印模版層可以一體 構成。然而所述第二網印模版層也可以由獨立於所述第一 網印模版層的網印模版層構成。所述獨立的網印模版層可 以由光敏層製成或者由基於聚乙烯醇、毛細膜或者固體殘 0留物（Festresist)的乳劑構成。所述獨立的網印模版層也 可以具有金屬層，所述金屬層通過電鑛塗覆來施加。 【實施方式】 圖1示出根據本發明的網印模版的第一網印模版層5〇 的橫截面圖。網印模版層5〇具有第一缺口 ！，其中，第一 缺口 1在第-頂面2上具有印刷介質入口 3，而在第一底 面4上具有印刷介質出口 5。 如此構造第 '網印模版層5〇,即，入口 3的面積7在 沿投影方向6垂直於該面積7投影時最多在局部與出口 5 ^積8相疊。這意味著，或者這兩個面積7或者$根本 叠，或者這兩個面積7或者8僅部分地重叠。以下將 二面積7和8部分重疊的區域描述為重疊面9。該重叠 :終小於面積7或者8。根據本發明的—個實施方式， 9的尺寸不超過面積7或者面積8的3G%D優選的 201107151 是，這兩個面積7和8不重疊，從而也就不存在重疊面9t 在圖1至圖3所示的第一網印模版層5〇中，第一缺口 • 1的在入口 3和出口 5之間的壁13關於網印模版層“的 底面4按照大約7〇。的角度範圍取向，參見附圖標記14。 因而第一缺口 1沿其整個長度從網印模版1〇〇的第一頂面 2傾斜延伸至第一底面扣在第一網印模版層別的情況下， 將印刷介質30送入該傾斜的第一缺口 ！比送入垂直於第一 〇網印模版層的頂面取向的缺口更容易。圖2示出印刷介質 3〇,其借助於到板10送入第—缺口。為此，該到板沿運動 方向11貼近網印模版層50的第一頂面2滑動。 在圖2所示情況下，完全送入第一缺口丨的印刷介質 30已到達位於第一網印模版層5〇下方的基板2〇並且接觸 其表面。&果在隨後的步驟中從基板2〇纟除該網印模版 層，那麼底面4上的棱邊12起到分離棱邊的作用從而從 該棱邊處開始剪斷該印刷介質，參見圖3。印刷介質3〇的 Ο -部分留在基板20上’這裏作為三角形部分32示出，同 時印刷介質30的其他部分保留在第—網印模版層5〇中。 然而’印刷介f 30在基板上和在網印模版層5〇中的份額 是根據該分離棱邊來預先確定的，並且可以报好地再現， 因而實現將印刷介質均勻施加到基板2〇上。 圖4不出根據第—實施方式的網印模版⑽。網印模版 100具有第’網印模版層50和第二網印模版層5 i，這兩個 網印模版層彼此牢固連接。網印模版1〇〇在第一網印模版 層50中具有兩個缺Π1，其中，該第一缺口丄終結於第一 201107151 底面4。在該第—底面4的下方, Μ. ± ^ 以存在階梯的方式構造 具有第一缺口 52的第二網印模 、版層5卜從而網印模版1〇〇 八有第二頂面53和第二底面 +人仿 乐一缺口 52具有以垂直 ;第一頂面53和第二底面54 的方式取向的壁。第二頂面 53與第一網印模版層50的第-底面4連接。在第一底面4 和第二底面54之間的該區域中可以積聚從第—頂面2被擠 塵穿過這些缺口 1和第·缺 和弟一缺口 52的印刷介質3〇，並且在201107151 VI. Description of the Invention: [Technical Field] The present invention relates to a screen printing stencil having a first screen printing stencil layer including a first notch and a second screen printing stencil layer including a second notch, thereby printing medium A wheel can be traversed from the top surface of the first screen printing stencil through the first notch and the second notch toward a substrate that can be disposed below them. Ο [Prior Art] The printing medium is applied to the screen printing stencil during screen printing or in the stencil printing method, and then the printing medium is fed by using a squeegee that moves along the top surface of the screen stencil or moves against the top surface. The gap of the screen printing template. The printing medium can be conveyed toward the bottom surface by one or more movements of the squeegee and reach the substrate disposed thereunder. The print medium does not reach the area covered by the screen stencil, thereby forming a printed pattern (Druckbild) on the substrate, the printed pattern substantially corresponding to the gap of the screen stencil. The use of screen printing and screen printing templates has long been known and has been tested. However, if the size of the notch in the screen printing stencil is small, the squeegee will be pressed against the screen stencil under relatively large force so that the printing medium can also be transported to the bottom surface and will not go. The roads there are attached to these small gaps. This kind of pressure is disadvantageous because it shortens the service life of the screen printing stencil, and the top surface of the screen printing stencil plus 201107151 is also relatively worn. . If the screen printing stencil is removed from the substrate after the printing medium has been slid, in the case of a small gap, in particular, the printing medium adheres to the screen stencil and does not adhere to the substrate. Thus, the printing medium is absent on the substrate. Conversely, if the print medium adheres to the substrate (as specified), then a portion of the print medium will remain in these gaps. As a result, the layer thicknesses of the printed areas on the substrate vary. 〇 In addition, masking based on screen printing stencils (such as fabrics) can also vary in layer thickness. More print media passes through the stencil at the location of the fabric opening than at the intersection. In the case of a high viscosity of the printing medium (wherein the medium does not flow in the lateral direction), the thickness profile of the print (H0henpr0fU) has a significant height difference. SUMMARY OF THE INVENTION The object of the present invention is therefore to provide a screen printing stencil that uses the net U stencil to obtain a reliable footprint on a substrate with a small gap, which is more durable than previous stencils. A high layer thickness can also be obtained when the printing medium is applied relatively wide on the substrate. This object is solved by the defect of the independent request item. An advantageous improvement of the invention is the subject matter of the subsidiary claim. The present invention relates to a screen printing stencil having a first screen printing stencil layer including a first top surface and a first bottom surface, wherein the stencil has a first notch, and the first notch is penetrated from the top surface Bellows to the bottom surface, wherein the no. 201107151 缺口 a notch has a print medium inlet on the first top surface and a print medium outlet on the first bottom surface, wherein the population is vertical in area At least partially overlapping the area of the outlet when the area is projected, wherein the screen printing stencil has a second screen printing layer 纟 comprising a second top surface and a second bottom surface, the second network The second top surface of the stamp layer is connected to the first bottom surface of the first screen printing layer, wherein the first screen printing layer has a second π, & and the printing medium can The top surface of the first screen printing stencil layer is conveyed through the first notch and the second notch to a substrate that can be disposed under them. In this configuration of the screen printing stencil, the printing medium is fed not only orthogonally or perpendicularly to the top surface of the screen printing stencil, but also in a direction away from the normal. This simplifies the transport of the print medium towards the substrate so that the print medium can be transported through the gap with a small force consumption by the squeegee. Thus, the durability of the screen printing stencil can be obtained. According to an embodiment of the invention, the wall of the first notch is greater than zero with respect to the first bottom surface of the screen stencil within the range of the outlet. And less than 90. The orientation is within the range of angles. Thus, a “separating edge” is formed which makes it possible to cut the printing medium in a defined manner and to prevent the printing medium from completely adhering in the first recess. It is particularly advantageous if the wall of the first recess is The bottom surface between the inlet and the outlet with respect to the first screen printing stencil is oriented within an angular range greater than 〇 and less than 9 。. Thus there is a first notch that is inclined relative to the bottom surface so that during squeegee movement In the case of the preferred direction, the print medium can be fed into the first recess in a particularly easy manner. In this embodiment 201107151 there is also a separating edge. If the cross section of the first recess is at its inlet and outlet Between the irregularities, such as the reduction, the further step enhances the shearing of the printing medium. According to another embodiment of the invention, at least one of the indentations is provided with a coating. The passage area of the print medium, and the print has a smaller size, wherein the coating has a thickness, the thickness of which is at least the gap 5% of the small cross-sectional width, and the contact angle of the coating to water is in the range of 0 to 90. The contact angle is the angle at which the droplets on the surface of the solid material form an angle with respect to the surface. In the case of a contact angle in the range of 90, the liquid or paste-like printing medium forms a good interaction with the surface of the coating, so that most of the printing medium remains adhered when the screen printing stencil is removed from the printing substrate. In the notch coated in this way, this is further simplified by the action of the separating edges, so that a uniform layer thickness can be printed without excessive material being printed together from the top notch to the substrate. According to another embodiment of the present invention, the notch is provided with a coating such that the coating reduces the passage area of the printing medium and causes the footprint to have a smaller size 'wherein the coating has a thickness, the thickness being at least 5% of the minimum cross-sectional width of the notch, and the contact angle of the coating to water is in the range from more than 90 to 150. Only a small mutual mutual surface of the printing medium is formed here. The printing medium can be fed into the gap with less resistance. In addition, after the printing medium is missed and the screen printing template is removed from the substrate, the printing medium 201107151 retained in the gap can be removed at a small cost. When the substrate is removed from the screen stencil, only a small portion of the print medium fed into the gap remains in the gap. As a result, the print has a thickness equal to the thickness of the screen stencil. The first screen stencil layer and the The second screen printing stencil layer may be integrally formed. However, the second screen printing stencil layer may also be composed of a screen printing stencil layer independent of the first screen printing stencil layer. The independent screen printing stencil layer may be photosensitive The layer is formed or consists of an emulsion based on polyvinyl alcohol, a capillary film or a solid residue. The individual screen printing stencil layer can also have a metal layer which is applied by electro-mineral coating. . [Embodiment] Fig. 1 shows a cross-sectional view of a first screen printing stencil layer 5 of a screen printing stencil according to the present invention. Screen printing layer 5〇 has the first gap! The first gap 1 has a print medium inlet 3 on the first top surface 2 and a print medium outlet 5 on the first bottom surface 4. The 'screen printing stencil layer 5' is constructed such that the area 7 of the entrance 3 is at most partially overlapped with the outlet 5 。 8 when projected perpendicularly to the area 7 in the projection direction 6. This means that either the two areas 7 or $ are stacked, or the two areas 7 or 8 only partially overlap. The area where the two areas 7 and 8 partially overlap is described below as the overlapping face 9. This overlap: is ultimately less than the area of 7 or 8. According to an embodiment of the present invention, the size of 9 does not exceed the area 7 or the area 3 of 3G%D is preferably 201107151, the two areas 7 and 8 do not overlap, so that there is no overlapping surface 9t in Figure 1 to In the first screen printing layer 5 shown in Fig. 3, the wall 13 of the first notch 1 between the inlet 3 and the outlet 5 is oriented at an angle of about 7 inches with respect to the bottom surface 4 of the screen printing layer. Referring to the reference numeral 14. Thus, the first notch 1 extends obliquely from the first top surface 2 of the screen printing stencil 1 along its entire length to the first bottom surface buckle in the case of the first screen printing stencil layer, which will be printed The medium 30 is fed into the inclined first notch! It is easier than feeding a notch oriented perpendicular to the top surface of the first screen printing stencil layer. Figure 2 shows the printing medium 3〇, which is fed by means of the plate 10 - a gap. For this purpose, the plate is slid in the direction of movement 11 adjacent to the first top surface 2 of the screen stencil layer 50. In the case shown in Fig. 2, the printing medium 30 completely fed into the first notch 已 has arrived at the first A screen stencil layer 5 〇 under the substrate 2 〇 and contact the surface thereof. & The screen stencil layer is removed from the substrate 2, and the edge 12 on the bottom surface 4 acts as a separating edge to cut the printing medium from the edge, see Fig. 3. Printing medium 3 〇 The Ο - portion remains on the substrate 20 'shown here as a triangular portion 32 while the other portion of the print medium 30 remains in the first screen stencil layer 5 然而. However, the printing medium f 30 is on the substrate and on the screen printing The fraction in the stencil layer 5 is predetermined according to the separating edge and can be reproduced remarkably, so that a uniform application of the printing medium to the substrate 2 is achieved. FIG. 4 shows the screen printing according to the first embodiment. The stencil (10) has a first screen printing stencil layer 50 and a second screen stencil layer 5 i, and the two screen printing stencil layers are firmly connected to each other. The screen printing stencil 1 is in the first screen printing stencil layer 50 There are two defects 1 in which the first notch 丄 ends at the bottom surface 4 of the first 201107151. Below the first bottom surface 4, Μ. ± ^ constructs the second network having the first gap 52 in a stepped manner Impression, layer 5, and thus the screen printing template The second top surface 53 and the second bottom surface + human melody-notch 52 have walls that are oriented in a vertical manner; the first top surface 53 and the second bottom surface 54. The second top surface 53 and the first screen printing stencil layer 50 The first bottom surface 4 is connected. In this region between the first bottom surface 4 and the second bottom surface 54, the printing from the first top surface 2 can be accumulated through the gaps 1 and the first and second gaps 52. Medium 3〇, and at
基板20上形成較寬的印跡31。 第-網印模版層50可以與第二網印模版層51 —體構 成’參見圖5。這樣，第二網印模版層51可以這樣製造， 即，由唯 種模版材料製成階梯。然而也可以將獨立的 網印模版層51與第一網印模版層5〇組合在一起，以形成 網印模版100，如圖4所示。這種獨立的網印模版層5丨例 如可以疋基於聚乙烯醇、毛細膜或者固體殘留物的光敏乳 劑層’借助於光刻钱印刷法（lithografisches Verfahren ) 〇在該光敏乳劑層中形成階梯。獨立的網印模版層5丨也可以 通過結構化電鍍塗層的方式實現，具體實現方式是，在第 一底面4上構造臨時存在的網版’將該獨立的網印模版層 電艘至該網版中。在塗覆之後再次去除該電鑛網版 (Galvanikform )。 如果從基板20去除網印模版1〇〇,參見圖4,那麼在印 跡31上，在第一缺口 1的出口 5過去所處的位置碟形成隆 起33。然而由於印刷介質30在第一缺口 1中被剪斷，這 些隆起33相對較低，因而可以獲得印跡3 1沿其寬度延伸 201107151 的相對均勻的厚度。 在圖4中以虛線示出印刷介質3〇的三角形部分32，緊 跟在從基板20去除網印模版1〇〇之後首先剩下這些三角形 部分32。然而如果印刷介質具有足夠的粘度，這種粘度即 使在沒有其他的力作用的情況下仍然允許流動，那麼在印 跡31的上表面上印刷介質3〇的三角形部分32沿侧向流 下，從而得到印跡3 1的幾乎均衡的厚度型廓，並留下相對 較低的隆起3 3。 當然，印跡具有幾乎一致厚度的這種效果以相同方式也 出現在這樣一種網印模版中，Μ述網印模版與根據圖4的 實施方式相反僅具有唯--個第一缺口 i。 【圖式簡單說明】 結合下面的附圖說明本發明的其他優點和特徵，圖中： 圖1是根據本發明的網印模版的第—網印模版層的橫 截面圖； 圖2是根據本發明的網印模版的第-網印模版層的橫 截面圖，還一同示出了印刷介質； 圖K根據本發明的網印模版的第—網印模版層的橫 截面圖以及所印製的基板的側視圖U示出了印刷介 質； 圖4是本發明的網印模版的具有第—網印模版層和第 201107151 二網印模版層的第一實施方式的橫截面圖；以及 圖5是根據本發明的網印模版的第二實施方式的橫截 面圖。A wider footprint 31 is formed on the substrate 20. The first screen printing stencil layer 50 may be integrally formed with the second screen printing stencil layer 51 see Fig. 5. Thus, the second screen printing stencil 51 can be manufactured such that a step is made of a stencil material. However, it is also possible to combine the individual screen printing stencil layer 51 with the first screen printing stencil layer 5 to form a screen printing stencil 100, as shown in FIG. Such a separate screen printing layer 5, for example, can be used to form a step in the photosensitive emulsion layer by means of a photolithographic printing method based on a photosensitive emulsion layer of polyvinyl alcohol, a capillary film or a solid residue. The separate screen printing layer 5 can also be realized by a structured electroplating coating. The specific implementation is to construct a temporary screen on the first bottom surface 4 to electrically connect the independent screen printing layer to the In the screen version. The electronet screen (Galvanikform) was removed again after coating. If the screen printing stencil 1 is removed from the substrate 20, see Fig. 4, on the scribe 31, the ridge 33 is formed at the position where the exit 5 of the first notch 1 has passed. However, since the print medium 30 is sheared in the first notch 1, the ridges 33 are relatively low, so that a relatively uniform thickness of the print 31 along its width extending 201107151 can be obtained. The triangular portion 32 of the print medium 3 is shown in phantom in Fig. 4, and these triangular portions 32 are first left immediately after the screen printing stencil 1 is removed from the substrate 20. However, if the printing medium has sufficient viscosity, the viscosity is allowed to flow even without other forces, then the triangular portion 32 of the printing medium 3 流 flows downward on the upper surface of the print 31, thereby obtaining a blot. 3 1 has an almost balanced thickness profile and leaves a relatively low ridge 3 3 . Of course, this effect of the imprint having a nearly uniform thickness also occurs in such a screen printing stencil in the same manner, with the exception that the screen printing stencil has only a first notch i as opposed to the embodiment according to Fig. 4. BRIEF DESCRIPTION OF THE DRAWINGS Other advantages and features of the present invention will be described in conjunction with the following drawings in which: Figure 1 is a cross-sectional view of a first screen printing stencil layer of a screen printing stencil according to the present invention; A cross-sectional view of a first screen printing stencil layer of the inventive screen printing stencil, together with a printing medium; FIG. K is a cross-sectional view of the first screen printing stencil layer of the screen printing stencil according to the invention and printed A side view U of the substrate shows the printing medium; FIG. 4 is a cross-sectional view of the first embodiment of the screen printing stencil of the present invention having a first screen printing stencil layer and a 201107151 two screen printing stencil layer; A cross-sectional view of a second embodiment of a screen printing stencil according to the invention.
【主要元件符號說明】 1 第一缺口 2 第一頂面 3 印刷介質入口 4 第一底面 5 ° 印刷介質出口 6 投影方向 7 面積 8 面積 9 重疊面 10 刮板 11 運動方向 12 棱邊 13 壁 20 基板 30 印刷介質 31 印跡 32 三角形部分 11 201107151 33 隆起 50 第一網印模版層 51 第二網印模版層 52 第二缺口 53 第二頂面 54 第二底面 100 網印模版 Ο ο 12[Main component symbol description] 1 First notch 2 First top surface 3 Printing medium inlet 4 First bottom surface 5 ° Printing medium outlet 6 Projection direction 7 Area 8 Area 9 Overlapping surface 10 Scraper 11 Movement direction 12 Edge 13 Wall 20 Substrate 30 Print medium 31 Blot 32 Triangle portion 11 201107151 33 Bulge 50 First screen stencil layer 51 Second screen stencil layer 52 Second notch 53 Second top surface 54 Second bottom surface 100 Screen printing Ο ο 12