Method for producing a display device, and display device

Abstract

The invention relates to a method for producing a thin and substantially fracture-resistant display device comprising a display, wherein an upper layer having a surface facing an observer is arranged on light-emitting luminous surfaces of the display, wherein micro-passages for transmitting generated light from the light-emitting luminous surfaces of the display are formed in the upper layer and form micro-openings in the surface facing an observer, wherein a substantially planar surface facing the observer is created on the upper layer, and wherein creating the substantially planar surface comprises processing the surface of the display device facing the observer by means of a laser and/or by means of machining in order to produce the substantially planar surface. Furthermore, the invention relates to a display device.

Claims

1. A thin display device with a display, the display comprising a light-emitting layer having a plurality of light sources and an upper layer arranged over the light emitting layer, the upper layer having a display surface facing a viewer, wherein micro-passages are formed in the upper layer extending from the light emitting layer to micro-openings in the display surface for allowing transmission of light generated by the light sources from the light emitting layer to said microopenings in the display surface facing a viewer, wherein at least one functional layer is formed on the upper layer, the functional layer comprising at least one of: a solar layer for generating power; a touch-sensitive layer for acquiring input; a pressure-sensitive layer for recording pressure; a temperature-sensitive layer for measuring a temperature; and a capacitive layer for measuring a capacity.

2. A thin display device with a display, the display comprising a light-emitting layer having a plurality of light sources and an upper layer arranged over the light emitting layer, the upper layer having a display surface facing a viewer, wherein micro-passages in the form of beam shaping devices are formed in the upper layer extending from the light emitting layer to micro-openings in the display surface for allowing transmission of light generated by the light sources from the light emitting layer to said micro-openings in the display surface facing a viewer, wherein a ratio of an area of an inlet of said beam shaping device and an area of an outlet of said beam shaping device is less than or equal to 1:25.

3. A thin display device with a display, the display comprising a light-emitting layer having a plurality of light sources and an upper layer arranged over the light emitting layer, the upper layer having a display surface facing a viewer, wherein micro-passages are formed in the upper layer extending from the light emitting layer to micro-openings in the display surface for allowing transmission of light generated by the light sources from the light emitting layer to said micro-openings in the display surface facing a viewer, wherein the upper layer between micro-passages comprises a material adapted to improve the reception of radio signals for antennas.

4. A thin display device with a display, the display comprising a light-emitting layer having a plurality of light sources and an upper layer arranged over the light emitting layer, the upper layer having a display surface facing a viewer, wherein micro-passages in the form of beam shaping devices are formed in the upper layer extending from the light emitting layer to micro-openings in the display surface for allowing transmission of light generated by the light sources from the light emitting layer to said micro-openings in the display surface facing a viewer, the at least one beam shaping device comprising at least partially a translucent material, wherein the upper layer between micro-passages comprises at least one element to measure noise or emit noise.

5. A thin display device with a display, the display comprising a light-emitting layer having a plurality of light sources and an upper layer arranged over the light emitting layer, the upper layer having a display surface facing a viewer, wherein micro-passages in the form of beam shaping devices are formed in the upper layer extending from the light emitting layer to micro-openings in the display surface for allowing transmission of light generated by the light sources from the light emitting layer to said micro-openings in the display surface facing a viewer, the at least one beam shaping device comprising at least partially a translucent material, wherein the upper layer between micro-passages comprises at least one actuator including any one or more of a micromotor, a micro-melt element, a micro-electromagnetic or magnetic element, a micro-air compression or micro-hydraulic element, a shape memory material, and an antenna.

Description

(1) In the following the invention will be explained in greater detail on the basis of exemplary embodiments in combination with associated drawings. The figures show schematically:

(2) FIGS. 1 to 5 show a first exemplary embodiment of a manufacturing method of a thin and substantially fracture resistant display device in various individual steps;

(3) FIG. 6a shows a top view of a section of a created, inventive display device;

(4) FIG. 6b shows a three-dimensional view of a beam shaping device 5 from FIGS. 1 to 5;

(5) FIGS. 7 to 11 show a second exemplary embodiment of a manufacturing method of a thin and substantially fracture resistant display device in various individual steps; and

(6) FIGS. 12 to 17 show a third exemplary embodiment of a manufacturing method of a thin and substantially fracture resistant display device in various individual steps.

(7) In the subsequent description the same reference numerals will be used for the same objects.

(8) It should be noted that the subsequent exemplary embodiments are to be understood as possible embodiment variants of a possible manufacturing method.

(9) Due to the bandwidth of the subject matter or method defined in the claims, further embodiments are conceivable and possible.

(10) FIGS. 1 to 6 show a first exemplary embodiment of a manufacturing method of a thin and substantially fracture resistant display device 1 in various individual steps.

(11) In the mentioned figurespresented in summarized forma method for producing a thin and substantially fracture resistant display device 1 with a display 2 is introduced. In so doing an upper layer 4 is arranged over light-emitting luminous areas 3 of the display 2, having a surface facing a viewer O. The upper layer 4 comprises substantially metal or a non-transparent or a non-light reflecting material.

(12) In the upper layer 4 micro-passages are formed for allowing generated light of the light-emitting luminous area 3 of the display 2 to pass, said micro-passages forming micro-openings A in the surface facing a viewer O.

(13) In a first portion of the inventive method comprising several steps, the upper layer 4 is fabricated.

(14) This happens among other things in a first steppresented in FIG. 1on a carrier T by means of laminated object modeling, a generative production method. In the process, in the fabrication of the upper layer 4presented concretelyseveral beam shaping devices 5 are created, wherein they are created at least partially out of a translucent material, in particular plastic. These beam shaping devices 5 form within the upper layer 4 the micro-passages for allowing light to pass.

(15) In the process in the present example according to FIG. 1 the beam shaping devices 5 can in each case have a diffusion element, in particular a diffuser (not shown in FIG. 1), and/or a collimator (not shown) and/or a concentrator. In FIG. 1 every beam shaping device 5 has furthermore a parabolic cross-section, as a result of which a concentrator is formed. This allows a concentration of incident light. In the process the lower end, which in comparison to the upper end is arranged on the carrier T, has a greater cross-section or diameter.

(16) In so doing the lower end of every beam shaping device 5, which is arranged on the carrier T, forms an inlet 6 and the upper end forms an outlet 7 for light.

(17) In a second manufacturing steppresented in FIG. 2the surface of the beam shaping devices 5 is covered or coated or painted with an electrically conductive material 8. In other words, the beam shaping devices 5 now comprise, at least on their surface facing a viewer, an electrically conductive material 8. The material 8 can also be configured in addition without electrical conductivity or only opaquely.

(18) In FIG. 2 in the process the beam shaping devices 5 are created by means of a thin layer method, which is sputtering and/or a galvanic application and/or a nanoimprint and/or a roller embossing method and/or an injection molding method. In the present case the forming of the beam shaping devices 5 comprises a sputtering with a metal, in particular with aluminum. As a result, in addition to the electrical conductivity, a light-reflecting surface can be generated easily and cost-effectively from a light material. Hence light within the concentrator of every beam shaping device 5 or within every beam shaping device 5 can be reflected on the areas covered by metal such that at the inlet 6 incident light is concentrated or bundled to the outlet 7 of every beam shaping device 5 by means of the concentrator.

(19) In FIG. 3 a further substep of the fabrication of the upper layer 4 is schematically shown. In so doing the fabrication of the upper layer comprises a generative production method, in particular a molding of a material. The molding or fabrication of the upper layer features a filling of the intermediate spaces 9 between the beam shaping devices 5. As a result among other things the mechanical stability is increased.

(20) In addition, the quantity of material used for filling, which in the present case is preferably an opaque plastic or metal, completely covers the beam shaping devices 5. As shown, during molding no substantially plane surface can be created on the upper layer 4.

(21) Therefore, in a subsequent steppresented in FIG. 4a substantially plane surface facing the viewer O is created on the upper layer. In the process, in the forming of the substantially plane surface an optical passage is created, so that light from the beam shaping devices 5 can enter and/or exit. As a result the beam shaping devices 5 are created at least partially or completely within the upper layer.

(22) To express the above described circumstances relating to FIG. 3 in other words, by creating of a plane surface O micro-openings A are generated in the upper layer 4, which make it possible for light at the outlet 7 of the beam shaping devices 5 to exit.

(23) The forming of the substantially plane surface O comprises a processing of the surface facing the viewer O of the display device 1 by means of a material removing method, in particular by means of grinding and/or polishing. It is also possible by means of a laser and/or by means of machining, preferably by means of milling and/or boring, and/or by means of a chemical process, preferably by means of etching, and/or by means of polishing and/or grinding to generate a surface O or a surface layer.

(24) To summarize for the step described in FIG. 4 it can be pointed out that the processing of the surface facing the viewer O comprises a generation of a common plane surface, wherein the upper layer 4 and a plurality of beam shaping devices 3, in particular their outlets 7, are processed such that light can exit from the outlets 7 of the beam shaping devices 3.

(25) Generally speaking, the fabrication of the upper layer 4 happens by means of a generative production method, wherein along with the forming of the beam shaping devices 5, the fabrication of the upper layer 4 can also feature a forming of a further layer and/or at least one functional layer.

(26) In so doing the fabrication of the upper layer comprises a forming of a surface layer forming a surface or an outer surface, which forms the surface O facing a viewer. In the present example however the upper layer 4 only has one layer, in which the beam shaping devices 5 are embedded. Hence in FIG. 4 the upper layer 4 corresponds to the surface layer.

(27) Furthermore, the forming of the surface layer can comprise an application of a surface structure, which can be configured to be hydrophobic and/or oleophobic and/or bacteriophobic and/or translucent.

(28) After the processing of the surface facing the viewer O by generating a common plane surface the carrier T is likewise removed. This happens with the help of an abrasive procedure, in particular by means of grinding and/or polishing. It is also possible to remove the carrier T by means of a laser and/or by means of machining, preferably by means of milling and/or boring, and/or by means of a chemical process, preferably by means of etching, and/or by means of polishing and/or grinding.

(29) In a further steppresented in FIG. 5the display 2 for forming of the thin and substantially fracture resistant display device 1 is arranged at the upper layer 4 from FIG. 4.

(30) In so doing, the display comprises 2 OLEDs or a micro display as light-emitting luminous areas 3, which are protected by a glass substrate G. The upper layer 4 having a surface facing a viewer O is arranged on these light-emitting luminous areas 3 of the display 2 or on the glass substrate G.

(31) More precisely, the micro-passages formed in the upper layer or the beam shaping devices 5 forming the micro-passages are arranged with their inlet 6 at light-emitting luminous areas 3 of the display 2 or on the glass substrate G. In the process, ideally each beam shaping device 5 is arranged above a light-emitting luminous area 3, so that a maximum degree of light of the beam shaping device can be made available.

(32) As a result the outlets 7 of the beam shaping devices 5 are arranged on the surface facing a viewer O of the upper layer 4. Viewed from the other side, the OLEDs or the micro display 2 outside of the micro-passages, formed by the beam shaping devices 5 within the upper layer 4, are arranged such that the light generated from the luminous areas 3 can pass through the upper layer 4. In other words, light from the light-emitting luminous areas 3 enters into the inlets 6 and exits the outlets 7. Henceas already indicatedthe micro-passages or the beam shaping devices 5 forming the micro-passages are used to let through light, so that generated light of the light-emitting luminous areas of the display in the surface O facing a viewer can exit from the micro-openings A.

(33) FIG. 6a shows a top view of a section of a created, inventive display device 1.

(34) In so doing, during the manufacturing the micro-openings A are created or incorporated on the surface facing a viewer O of the upper layer 4 with a percentage of less than 10% of the total surface O of the upper layer 4 facing the viewer. In the process, in the upper part of the display device 1 the micro-openings A are spaced further apart from one another than in the lower part. Consequently various distances can be realized and concurrently the target relating to the percentage of less than 10% of the total surface for the micro-openings can be ensured.

(35) FIG. 6b is a three-dimensional view of a beam shaping device 5 from FIGS. 1 to 5.

(36) In so doing, FIG. 6b shows schematically that the ratio of the area FE of the inlet 6 of the beam shaping device 5 or the ratio of the maximum area of the beam shaping device 5 to the area FA of the outlet 7 of the beam shaping device 5 is less than 1:25.

(37) Furthermore FIG. 6b indicates that the ratio of the area FA exiting through the upper layer beam shaping device 5 to the area of the upper layer is less than 1:100.

(38) It can also be seen from FIG. 6b that the distance H from inlet 6 to outlet 7 of the beam shaping device 5 in proportion to the maximum diameter D at the inlet 6 of the beam shaping device 5 is equal to 1:1.

(39) In the process, the outlet 7 of the beam shaping device 5 has a diameter of less than 50 m. An even smaller diameter is preferable.

(40) FIGS. 7 to 11 show a second exemplary embodiment of a manufacturing method of a thin and substantially fracture resistant display device in various individual steps.

(41) In so doing all of the steps of the second exemplary embodiment are identical to the first. However the beam shaping devices 5 are different. Therefore, the following text only covers the differences, without repeating the further explanations, which can be applied analogously from the first exemplary embodiment to the second.

(42) So is also, described in detail, the manufacturing step from FIG. 1 is identical to the manufacturing step according to FIG. 7, the manufacturing step from FIG. 2 is identical to the manufacturing step according to FIG. 8, the manufacturing step from FIG. 3 is identical to the manufacturing step according to FIG. 9, etc. All of the explanations, as already mentioned, about the respective corresponding steps can be transferred analogously or even identically from the first exemplary embodiment to the second.

(43) The difference between the first and second exemplary embodiment is the embodiment of the beam shaping devices 5.

(44) According to the second exemplary embodiment, in contrast to the beam shaping devices of the first exemplary embodiment, these have a sacrificial element 10 on the outlet side.

(45) Said sacrificial element is configured to be cylindrical in the present example and extends one beam shaping device 5 upward, so that in total the upper layer 4 increases in thickness.

(46) Of course the sacrificial elements 10 of the beam shaping devices 5 can take on further shapes. Thus, they can also be configured rectangular or conical. Furthermore, the sacrificial element 10 is fabricated from the same material as the previously described beam shaping devices 5 and hence they are preferably configured in one piece or one part with one another. The material can be a translucent material which can absorb and transmit light.

(47) Analogous to FIG. 3, in FIG. 9 the upper layer 4 is fabricated by means of a generative production method, in particular by means of molding of a material. The molding or fabrication of the upper layer 4 features a filling of the intermediate spaces 9 between the beam shaping devices 5. As a result among other things the mechanical stability is increased.

(48) In so doing the quantity of material used for filling, in particular plastic or metal, covers the beam shaping devices 5 at least on the surface facing the viewer O such that at least one region of the sacrificial element is free from material or the sacrificial element 10 is enclosed to a great extent with material.

(49) In the subsequent step according to FIG. 10, analogous to FIG. 4 a substantially plane surface facing the viewer O is created on the upper layer 4. In the process, in the forming of the substantially plane surface O an optical passage is created, so that light from the beam shaping devices 5 can enter and/or exit. As a result the beam shaping devices 5 are created at least partially or completely within the upper layer.

(50) The forming of the substantially plane surface O comprises a processing of the surface facing the viewer O of the display device 1 by means of a material removing method, in particular by means of grinding and/or polishing. It is also possible by means of a laser and/or by means of machining, preferably by means of milling and/or boring, and/or by means of a chemical process, preferably by means of etching, and/or by means of polishing and/or grinding to generate a surface O or a surface layer.

(51) In so doing the advantage of the sacrificial element 10 also comes to light. This is due to the fact that production tolerances in the forming of the beam shaping elements 5 together with the sacrificial elements 10 can be designed more generously, as a result of which Production costs can be lowered.

(52) While in the case of the first exemplary embodiment after the molding it is necessary to grind exactly to the height of the beam shaping devices in order to obtain a maximum of light output, this is no longer necessary for the second exemplary embodiment due to the sacrificial elements 10. The height of the sacrificial elements 10 can be sacrificed for the abrasion without seeing losses in the light output for beam shaping devices 5. Hence in abrasion e.g. in the form of a grinding process a greater tolerance can be used in the abrasion. Furthermore, as a result of this less scrap is produced, and hence productivity is increased.

(53) To express the above statements regarding FIG. 10 in different wording, in creating a plane surface O, micro-openings A are generated in the upper layer 4, wherein these micro-openings A make it possible for light at the outlet 7 formed by the sacrificial elements 10 to exit the beam shaping devices 5.

(54) To summarize, for the step described in FIG. 10 it can be stated that the processing of the surface facing the viewer O comprises a generation of a common plane surface O, wherein the upper layer 4 and a plurality of beam shaping devices 3, in particular their outlets 7, are processed such that light can exit from the outlets 7 of the beam shaping devices 3. In so doing the outlets 7 are formed by sacrificial elements 10 of the beam shaping devices 5.

(55) In general, it can also be stated here that the fabrication of the upper layer happens by means of a generative production method, wherein the fabrication of the upper layer 4 likewise comprises a forming of a further layer and/or at least one functional layer and/or the forming of the beam shaping devices 5.

(56) Furthermore here too, as in the case of the first exemplary embodiment according to FIG. 4, after the processing of the surface facing the viewer O by generating a common plane surface the carrier T is removed. This is performed with the help of an abrasive procedure, in particular by means of grinding and/or polishing. Of course it is also possible here to remove the carrier T by means of a laser and/or by means of machining, preferably by means of milling and/or boring, and/or by means of a chemical process, preferably by means of etching, and/or by means of polishing and/or grinding.

(57) In the subsequent steppresented in FIG. 11the display 2 is arranged on the upper layer 4 from FIG. 10 to form the thin and substantially fracture resistant display device 1. Please refer to our statements about FIG. 5.

(58) FIGS. 12 to 17 show a third exemplary embodiment of a manufacturing method of a thin and substantially fracture resistant display device in various individual steps.

(59) In so doing in a first step, indicated in FIG. 12, a matrix 11 is created for a stamping tool and/or an injection molding tool. In order to show the variants from the previous two exemplary embodiments, i.e. beam shaping devices 5 with and without sacrificial element 10, simultaneously, in FIG. 12 or 13 both variants are presented. Two different embodiments for sacrificial elements 10 are also shown.

(60) After the forming of a matrix, with the help of said matrix and by means of a nanoimprint and/or of a roller embossing methods and/or of an injection molding methods beam shaping devices 5, as shown in FIG. 12 or 13, are created with and without sacrificial element 10. In the process the beam shaping devices 5 are connected via a carrier T.

(61) With reference to FIG. 13 the first, left sacrificial element 10 is an embodiment configured identically to the above described, second exemplary embodiment. By contrast, the second, right sacrificial element 10 has a conical shape tapering from bottom to top. Thus various shapes can be conceived and also implemented for sacrificial elements 10.

(62) As already mentioned with respect to the two previous exemplary embodiments, one beam shaping device 5 in the third exemplary embodiment also has an inlet 6 and an outlet 7, wherein the outlet 7 can now be found on the sacrificial element 10.

(63) In FIG. 14 the upper layer 4 is further fabricated by means of galvanic application, wherein the intermediate spaces 9 between the beam shaping devices 5 are filled. With the help of this measure the mechanical stability is increased.

(64) Furthermore the quantity of material used for filling, which in the present case is a metal, preferably titanium, now completely covers the beam shaping devices 5 along with sacrificial elements 10. As shown, in the case of galvanic application no substantially plane surface O is created on the upper layer 4.

(65) Ideally, another step of the method can precede the filling of the intermediate spaces 9 by means of galvanic application. In this step preferably the surfaces of the beam shaping devices 5 are vaporized or sputtered with a light-reflecting metal. This allows the beam shaping devices 5 to concentrate the amount of light from the inlets 6 to the outlets 7, in order to reduce losses and conserve energy. The application of such a layer is described analogously for the first and second exemplary embodiments, however in connection with an electrically conductive material, wherein this material can also be configured to be light-reflecting, such as e.g. aluminum.

(66) In a subsequent steppresented in FIG. 15a substantially plane surface facing the viewer O is created on the upper layer 4. In the process, in the forming of the substantially plane surface an optical passage is created, so that light can exit from the sacrificial elements 10 or the outlets 7 of the beam shaping devices 5 or light can enter and/or exit from the beam shaping devices 5. As a result the beam shaping devices 5 are created at least partially or completely within the upper layer.

(67) In addition the carrier T is removed. The forming of a substantially plane surface O facing the viewer and the removal of the carrier T is carried out by means of a reworking of the upper layer 4. In the process the reworking of the upper layer 4 is carried out by means of a laser and/or by means of machining, preferably by means of milling and/or boring, and/or by means of a chemical process, preferably by means of etching, and/or by means of polishing, in order to generate the upper layer 4 or a surface layer, if the upper layer 4 is composed of several layers.

(68) For the sake of simplicity in the subsequent step according to FIG. 16 the display of the sacrificial elements 10 is omitted. However, please note that the subsequent description also applies to beam shaping devices 5 with sacrificial elements 10.

(69) According to FIG. 16 in the subsequent step according to FIG. 15 the upper layer 4 is reworked such that by means of etching recesses 11 are created at the outlets 7 of the beam shaping devices 5. In so doing prior to the etching process by means of a paint that can be applied and exposed and by means of a mask and a subsequent exposure process regions are defined on the upper layer 4 that are supposed to be removed or protected during etching. In other words, this process is configured analogously to that of microchip manufacturing.

(70) In the created recesses 12, which are arranged on each outlet 7 of the beam shaping devices 5, one diffusion element 13 each, is designed as a diffuser. It is also possible instead of or in addition to position a collimator in a recess 11.

(71) In so doing the diffusion elements 13 can be created by an application by means of a spackling process, in which a spackling compound penetrates into the recesses 12 formed by the micro-openings.

(72) After the upper layer 4 has been completed, in a further steppresented in FIG. 17it can be arranged on the display 2 for completion of the thin and substantially fracture resistant display device 1.

(73) To this end the upper layer 4 is arranged on a glass substrate G of the display above the light-emitting luminous areas 3 of the display 2. The arrangement can for example be supported with a bonding agent, so that the upper layer 4 is connected to the display 2.

(74) More precisely, the micro-passages formed in the upper layer or the beam shaping devices 5 forming the micro-passages with their inlet 6 are arranged over light-emitting luminous areas 3 of the display 2 or above light-emitting luminous areas 3 of the display 2. As a result the outlets 7 of the beam shaping devices 5 are arranged on the surface facing a viewer O of the upper layer 4.

(75) The display 2 has OLEDs or a micro display as light-emitting luminous areas 3. Therefore the OLEDs or the micro display outside of the micro-passages, formed by the beam shaping devices 5 within the upper layer 4 are arranged such that the light generated from the luminous areas 3 can pass through the upper layer 4. In other words, light from the light-emitting luminous areas 3 enters into the inlets 6 if a beam shaping device 5 and exits from their outlets 7. Henceas already indicatedthe micro-passages or the beam shaping devices 5 forming the micro-passages are used to let light pass, so that generated light of the light-emitting luminous areas 3 of the display 2 forms micro-openings A in the surface O facing a viewer.

(76) In the following, further embodiments of the inventive method are briefly outlined. These statements can be applied to all of the presented exemplary embodiments.

(77) Thus, it is for example possible that the fabrication of the upper layer 4 comprises a forming of a further layer and/or at least one functional layer and/or in addition to the forming of beam shaping devices 5. In the process, a solar layer can be created for generating power as at least one functional layer and/or a touch-sensitive layer can be created for acquiring input and/or a pressure-sensitive layer can be created for recording pressure and/or a temperature-sensitive layer can be created for measuring a temperature and/or a capacitive layer can be created for measuring a capacity as at least one functional layer.

(78) In the process, it is conceivable that in forming of the at least one functional layer at least one sensing element is introduced into the functional layer, wherein preferably the at least one sensing element can be configured as a touch sensor and/or as a temperature sensor and/or as a pressure sensor and/or as a capacitive sensor.

(79) It is also possible that in forming of the beam shaping devices 5 at least one sensing element is arranged between two beam shaping devices. Alternatively or in addition the display or its light-emitting side can also have at least one sensing element. In addition, it is conceivable that at least one sensing element is applied between the display and the upper layer.

(80) The at least one sensory element can be a sensor, in particular a two-dimensional and/or three-dimensional sensor, preferably an image sensor and/or a touch-sensitive and/or a pressure-sensitive and/or gas-sensitive sensor, in particular a piezo element.

(81) Furthermore, it is not compulsory to create the upper layer 4 on a carrier T. It is also possible to arrange the upper layer 4 directly on the glass substrate G or the display 2 luminous area 3. As a result, an even thinner and hence lighter display device can be created.

(82) Regarding all of the aforementioned exemplary embodiments and their possible variants, it should be noted that they can, of course be combined with one another. Such combinations arise in particular from the general part of the description.

LIST OF REFERENCES

(83) 1 Display device 2 Display 3 Luminous area 4 Upper layer 5 Beam shaping device 6 Inlet 7 Outlet 8 Electrically conductive material 9 Intermediate space 10 Sacrificial element 11 Matrix 12 Recess 13 Diffusion element A Micro-opening T Carrier G Glass substrate FA Area of the outlet FE Area of the inlet D Diameter at the inlet H Distance