Method for applying a coating to at least one electronic component and coating device

Abstract

The invention relates to a method for applying a coating to at least one electronic component, comprising the following steps: A) providing a coating device (1) comprising a coating roller (2), the coating roller (2) being rotatable about an axis of rotation (R); b) providing a coating material (3) on the coating roller (2); c) providing at least one electronic component (10); d) moving the at least one electronic component (10) along the rotating coating roller (3) in order to obtain a coating (12) of at least a portion of the electronic component (10). Furthermore, a coating device (1) for applying a coating (12) to at least one electronic component (10) is described.

Description

Technical Field

[0001] The invention relates to a method for applying a coating to at least one electronic component, preferably to a plurality of electronic components. Furthermore, the invention relates to a coating device for applying a coating to at least one electronic component, preferably to a plurality of electronic components. Background Art

[0002] The increasing demand for NTC (Negative Temperature Coefficient) temperature sensors requires cost-effective production by reducing material and energy consumption. However, high reliability requires a simultaneous combination of new materials and production technologies.

[0003] An essential requirement for high reliability is the application of protective coatings (e.g. mechanical, climatic, thermomechanical, chemical, thermal, light, etc. protection) with defined geometrical dimensions (coating thickness, head diameter and coating length), typically using powder and resin based coating materials.

[0004] Currently, the state-of-the-art technologies for coating line-contact electronic components are fluidized bed, spray gun and dip coating techniques.

[0005] These techniques result in high wastage of coating material (ratio between coating material needed in the component and coating material lost). In addition, unused coating material needs to be recovered, resulting in accumulation of foreign matter.

[0006] As the demand for higher precision required by miniaturized designs increases, the use of the above techniques leads to yield losses. Besides this, in order to maintain the chemical and physical composition of the coating material, additional processing steps need to be foreseen to obtain constant results (continuous stirring to avoid sedimentation, degassing to remove trapped air). Summary of the invention

[0007] An object of the present disclosure is to provide a method and a coating device that solve the above-mentioned problems.

[0008] This object is achieved by a method and a coating device according to the independent claims.

[0009] According to a first aspect, a method for applying a coating to at least one electronic component is described. In particular, by this method, a coating is applied to at least a portion of at least one electronic component, preferably a plurality of electronic components. The method comprises the following steps:

[0010] In a first step A), a coating device is provided. The coating device comprises a coating roller. The coating roller can rotate about a rotation axis. Preferably, the coating roller can rotate in a rotation direction. The coating roller can be prevented from rotating in a direction opposite to the rotation direction. The coating roller can be motor driven. In particular, the coating roller can be driven by a motor of the coating device. The coating roller can comprise metal. The coating roller comprises a cylindrical shape.

[0011] In the next step B), a coating material is provided. The coating material is arranged on a coating roller, in particular on the outer surface of a cylindrical coating roller. The cylindrical outer surface of the coating roller can be completely wetted with the coating material. The coating material is evenly distributed on the coating roller. No bubbles are present in the coating material arranged on the coating roller.

[0012] The coating material may be viscous. The viscosity of the coating material may be between 4000 cP and 10000 cP. The coating material may include a liquid portion and a solid portion, i.e., the coating material may include an emulsion. In particular, the coating material may include a polymer. The solid weight of the coating material composition may be between 53.4% ​​and 57.4%.

[0013] No process steps are required to maintain the chemical and physical composition of the coating material. This means that no additional processing steps (such as continuous stirring to avoid precipitation, degassing to remove entrapped air, etc.) have to be foreseen. The coating material remains an emulsion during the entire process. Thus, a very simple process is provided, in which only a few process steps are required.

[0014] In a next step C), at least one electronic component is provided. Preferably, a plurality of electronic components may be provided. The electronic component may comprise an NTC temperature sensor device.

[0015] At least one electronic component may be mounted on a mounting element of the coating device. The mounting element may be slidable or movable.

[0016] The mounting element / at least one electronic component may be slidable, in particular horizontally slidable, along the longitudinal axis.The longitudinal axis may be perpendicular to the axis of rotation of the coating roller.

[0017] In the next step D), the coating roller is rotated. The coating roller rotates in a rotation direction. The coating roller rotates so that a certain thickness of coating material is generated.

[0018] The electronic component is moved. The electronic component passes through the coating roller. In particular, the electronic component is moved along the rotating coating roller, i.e., passes along the longitudinal axis, to obtain a coating of at least a portion of the electronic component. In other words, the electronic component is in contact with the coating material arranged on the outer surface of the coating roller and is at least partially coated with the coating material.

[0019] By the above method using roller technology, a uniform coating with well-defined dimensions is provided on at least part of the electronic component. No additional features of the machine / additional steps are required in the process.

[0020] Product costs can be minimized by:

[0021] a) Reduce process-related material waste by reducing uniformity requirements (stirring, leveling, degassing);

[0022] b) Reduce the accumulation of foreign matter;

[0023] c) Make the machine feature-less (no need for recovery, spraying, or dipping baths inside the machine);

[0024] d) Reduce process variation.

[0025] Thus, a very efficient and cost-effective method for forming coatings with well-defined dimensions for electronic components is provided.

[0026] According to one embodiment, in step D), the electronic component is moved along the longitudinal axis from a starting position to an end position. In particular, the mounting element on which the at least one electronic component is mounted can be moved laterally from the starting position to the end position. However, the movement of the electronic component in the opposite direction, i.e. from the end position to the starting position, can be prevented.

[0027] The longitudinal axis may be perpendicular to the axis of rotation. The at least one electronic component may be moved laterally relative to the rotating coating roller. However, movement of the coating roller along the longitudinal axis is prevented.

[0028] Furthermore, in step D, the electronic component can be brought into direct contact with the coating material. The electronic component can penetrate the coating material, in particular through the coating material thickness generated by the rotation of the coating roller. However, the electronic component can be prevented from coming into direct mechanical contact with the outer surface of the coating roller.

[0029] The direction of the viscous force of the coating material may be opposite to the direction of movement of the electronic component in step D), in particular opposite to the direction of movement along the longitudinal axis. Thus, in this step, the viscous coating material may be wound onto a portion of the electronic component to establish a coating of the electronic component. Thus, a very simple, efficient and stable method for providing a coating is disclosed.

[0030] According to one embodiment, in step D), a defined length of the electronic component is immersed through the coating material which is continuously rolled on a coating roller. Thus, a coating with well-defined geometrical dimensions can be provided.

[0031] According to one embodiment, a plurality of electronic components are coated by the method. The respective electronic component comprises a sensor head. The sensor head may comprise an upper portion of the electronic component comprising the coating. The sensor head comprises a diameter. In this case, the diameter of the sensor head denotes an extension of the sensor head perpendicular to a main longitudinal axis of the sensor head. The diameter of the sensor head may be small. In particular, the diameter may be smaller than the diameter of the sensor head of an electronic component having a coating achieved by a standard coating process, such as dip coating.

[0032] In addition, the diameter variation of the sensor head of the electronic component coated by the above method may be small. In particular, the variation may be small compared to the diameter variation of the sensor head of the electronic component coated by conventional coating techniques. In other words, the above method is very stable and produces a coating with well-defined dimensions.

[0033] According to another aspect, a coating device for applying a coating to at least one electronic component, preferably to a plurality of electronic components, is described. Preferably, the coating device corresponds to the coating device used in the above-described method. Therefore, all features described in conjunction with the method also apply to this aspect, and vice versa.

[0034] The coating device includes a coating roller. The coating roller may include a cylindrical member. The coating roller may include a smooth outer surface. The coating roller can rotate about an axis of rotation. The coating roller can rotate in a direction of rotation, such as in a counterclockwise direction. Rotation in a direction opposite to the direction of rotation can be prevented. In other words, the coating roller can only rotate in one direction. The coating roller rotates for coating at least one electronic component with a coating material.

[0035] The coating roller can be adapted and arranged to be wetted with the coating material. In particular, the outer surface of the coating roller can be covered, preferably completely covered, with the coating material. The coating material can be evenly distributed on the coating roller. In particular, no bubbles exist in the coating material provided on the coating roller.

[0036] The coating material may be viscous. The viscosity of the coating material may be between 4000 cP and 10000 cP. Preferably, the coating material comprises a polymer. The solid weight of the coating material composition may be between 53.4% ​​and 57.4%.

[0037] By means of the coating device, a uniform coating with well-defined dimensions can be applied to at least a portion of an electronic component. At the same time, the design of the device is very simple, since no additional functions, such as functions for homogenization and / or further mixing of the coating material, are required. Thus, a simple, reliable and cost-effective device is provided.

[0038] According to one embodiment, the coating device comprises a mounting element. The mounting element may be adapted and arranged to hold at least one electronic component, preferably a plurality of electronic components. The mounting element may be movable. In particular, the mounting element may be capable of horizontal (lateral) movement. The mounting element may be vertically fixed. The mounting element and therefore the electronic component may be capable of moving along a longitudinal axis. The longitudinal axis may be perpendicular to the axis of rotation of the coating roller.

[0039] By moving the electronic component horizontally relative to the rotating coating roller, the viscous coating material can be effectively and evenly distributed over a portion of the electronic component. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Additional features, modifications and advantages will become apparent from the following description of exemplary embodiments taken in conjunction with the accompanying drawings.

[0041] Figures 1a and 1b show perspective views of a coating device,

[0042] 2a to 2e show method steps for applying a coating to at least one electronic component,

[0043] Figure 3 Schematically showing the method steps for applying a coating to at least one electronic component,

[0044] Figure 4 schematically shows a perspective view of a coated electronic component,

[0045] Fig. 5a and Fig. 5b show diagrams illustrating the head diameter of a sensor device coated by the method according to the invention and a sensor device coated by conventional techniques. DETAILED DESCRIPTION

[0046] In the drawings, elements of the same structure and / or function may be represented by the same reference numerals.It should be understood that the embodiments shown in the drawings are illustrative representations and are not necessarily drawn to scale.

[0047] Fig. 1a and 1b show a coating device 1. The coating device 1 is adapted and arranged to apply a coating 12 to an electronic component 10, in particular to a portion of the electronic component 10. The coating device 1 is adapted to coat a large number of electronic components 10 simultaneously.

[0048] The coating device 1 comprises a coating roller 2. The coating roller 2 is rotatable about a rotation axis R. The coating roller 2 is unidirectionally rotatable. The coating roller 2 is prevented from moving in an axial direction.

[0049] The coating roller 2 comprises a cylindrical member. The coating roller 2 has a smooth outer (cylindrical) surface. A coating material 3 (see, for example, FIGS. 2b to 2d ) can be applied to the smooth outer surface of the coating roller 2 .

[0050] The coating material 3 is viscous. The viscosity of the coating material 3 is, for example, between 4000 cP and 10000 cP. Preferably, the coating material 3 comprises a polymer. The solid weight of the coating material composition may be between 53.4% ​​and 57.4%. The coating material 3 does not require a mixing step. In other words, the coating material remains an emulsion throughout the process.

[0051] The coating device 1 further comprises a motor 4. The motor 4 is adapted and arranged to drive the coating roller 2 (ie to rotate the coating roller 2). The coating device 1 further comprises a power supply 5 for electrically connecting the motor 4.

[0052] The coating device 1 further comprises a mounting element 6. The mounting element 6 is movable. The mounting element 6 can be moved horizontally. The mounting element 6 is prevented from rotating.

[0053] The mounting element 6 can be moved horizontally along the longitudinal axis A (FIG. 1b). The longitudinal axis A is perpendicular to the rotation axis R. The mounting element 6 can be moved along the longitudinal axis A from a starting position 7 to an end position 8 (see FIG. 2c and FIG. 2d). The mounting element 6 can be moved unidirectionally. In other words, the movement of the mounting element 6 in the opposite direction, i.e. from the end position 8 to the starting position 7, is blocked.

[0054] The mounting element 6 is adapted and arranged to hold a plurality of electronic components 10. For this purpose, the mounting element 6 comprises a plurality of recesses (see, for example, FIG. 2e ), into which the electronic components 10 are partially inserted. The recesses extend perpendicularly with respect to the main longitudinal axis of the mounting element 6. For example, as can be gathered from FIG. 2e , the opposite ends of the electronic components 10 protrude beyond the side surface of the mounting element 6.

[0055] In the following, in conjunction with FIG. 2a to FIG. 2e and Figure 3 The function of the coating device 1 is described in FIGS. 2a to 2e and Figure 3 The method steps for applying a coating 12 to at least one electronic component 10 are shown.

[0056] First (step A) of the method), the coating device 1 described above is provided ( FIG. 2 a ).

[0057] In the next step B), a coating material 3 is provided, as can be seen from FIG. 2b. The coating material 3 is arranged on the smooth outer surface of the cylindrical coating roller 2. In particular, the outer surface of the coating roller 2 is completely wetted with the viscous coating material 3. The coating material 3 is evenly distributed on the coating roller 2. No bubbles are present in the coating material 3 on the surface of the coating roller 2 (FIG. 2b to FIG. 2d).

[0058] As mentioned above, the solid weight of the coating material composition can be between 53.4% ​​and 57.4%. No mixing step is required for the coating material 3. The coating material 3 remains as an emulsion throughout the process.

[0059] In a next step C), the electronic component 10 is mounted on the mounting element 6. As can be gathered from FIG. 2c, the mounting element 6 is arranged at a lateral distance from the coating roller 2 and thus from the coating material 3.

[0060] As mentioned above, the mounting element 6 is horizontally / laterally movable along the longitudinal axis A. In this method step, the mounting element 6 and thus the corresponding electronic component 10 is located in a fixed horizontal / lateral position, the starting position 7 ( FIG. 2 c : left side of the coating roller 2 ).

[0061] In the next step D), the coating roller 2 is rotated about the axis of rotation R. This produces a certain thickness of the viscous coating material 3 (see also Figure 3 ).

[0062] The mounting element 6 / corresponding electronic component 10 moves along the rotating coating roller 2 (i.e., along the longitudinal axis A) from the starting position 7 toward the end position 8 (FIG. 2c and 2d). Therefore, the corresponding electronic component 10 is in direct contact with the coating material 3. The direction of the viscous force V of the coating material 3 is opposite to the direction in which the electronic component moves along the longitudinal axis A (see FIG. 2c and FIG. 2d). Figure 3 ), so that the electronic component 10 is partially covered with the adhesive coating material 3.

[0063] Only a limited length of the electronic component 10 (the portion of the electronic component 10 to be coated) is immersed through the coating material 3 continuously rolled on the coating roller 2, which can be seen from the Figure 3 At the end of the process, the mounting element 6 and thus the corresponding electronic component 10 is arranged in the end position 8 (FIG. 2d: right side of the coating roller 2), and the corresponding electronic component 10 includes the coating 12 (see FIG. 2e and Figure 3 ). The coating 12 includes a length L and a diameter D (the head diameter of the coated electronic component 10), as shown in FIG. Figure 3 and Figure 4 It can be seen in.

[0064] Figure 4 An example of a coated electronic component 10 is shown. The electronic component 10 may comprise a wire-contact electronic component. The electronic component 10 may comprise a sensor device designed to measure temperature, such as a miniaturized NTC temperature sensor device.

[0065] The electronic component 10 has a sensor element or a sensor chip 14 (see Figure 3). The sensor element 14 is preferably an NTC thermistor chip. The electronic component 10 further comprises two contact elements 13 for electrical contacting of the sensor element 14. The contact elements 13 preferably comprise wires. The contact elements 13 are electrically and mechanically connected to electrodes (not explicitly shown) of the sensor element 14.

[0066] The electronic component 10 further comprises a coating 12, i.e., a coating 12 realized by the aforementioned method. The coating 12 completely encloses the sensor element 14. The coating 12 constitutes a head 11 (sensor head) of the electronic component 10. The head 11 comprises the sensor element 14 and at least a part of the contact element 13 and the coating 12, such as Figure 3 and Figure 4 The coating 12 forms an outer shell of the upper portion of the electronic component 10 and protects the upper portion of the electronic component 10 from environmental influences.

[0067] The notch 12a of the coating 12 appears on the lower side of the coating 12. The head 11 extends from the upper end of the electronic component 10 to the upper limit of the notch 12a (ie, the total length L of the coating 12 / head 11).

[0068] The head 11 comprises a diameter D, ie an extension perpendicular to the length L. The diameter D of the head 11 varies only slightly. The diameter D of the head 11 achieved by the aforementioned method varies only slightly (see Figure 5A ). In contrast, the variation in head diameter of electronic components coated by conventional coating methods is statistically significantly higher (see Figure 5B ). Therefore, the above method is a stable process.

[0069] In summary, the variation of the sensor head diameter is statistically significantly lower with the coating method described above compared to conventional coating techniques. In absolute terms, the diameter D is also smaller compared to the head diameter of conventionally coated electronic components. Thus, compact and cost-effective electronic components with well-defined geometric dimensions are provided by the roller coating method.

[0070] The present invention is not limited to the embodiments based on the description thereof. On the contrary, the present invention includes any novel feature and any combination of features, in particular any combination of features in the claims, even if the feature or combination itself is not explicitly stated in the claims or embodiments.

[0071] Reference numerals

[0072] 1 Coating device

[0073] 2 Coating rollers

[0074] 3 Coating materials

[0075] 4 Motor

[0076] 5 Power supply

[0077] 6 Mounting components

[0078] 7 Starting Position

[0079] 8 End position

[0080] 10 Electronic components

[0081] 11 Head

[0082] 12 Coating

[0083] 12a Notch

[0084] 13 Contact elements

[0085] 14 Sensor element

[0086] R Rotation axis

[0087] D Head diameter

[0088] L coating length

[0089] V Viscosity

[0090] A Longitudinal axis

Claims

1. A method for applying a coating (12) to at least one electronic component (10), the method comprising the following steps: A) providing a coating device (1), said coating device (1) comprising a coating roller (2), wherein said coating roller (2) is rotatable about a rotation axis (R); B) providing a coating material (3) on the coating roller (2); C) providing at least one electronic component (10); D) moving at least one of the electronic components (10) along the rotating coating roller (2) to obtain a coating (12) on at least a portion of the electronic component (10).

2. The method according to claim 1, in, In step D), the electronic component (10) is moved along a longitudinal axis (A) from a starting position (7) to an end position (8), wherein the longitudinal axis (A) is perpendicular to the rotation axis (R).

3. The method according to claim 2, in, The direction of the viscous force (V) of the coating material (3) is opposite to the direction in which the electronic component (10) moves along the longitudinal axis (A).

4. The method according to any one of the preceding claims, in, In step D), the electronic component (10) is brought into direct contact with the coating material (3).

5. The method according to any one of the preceding claims, in, In step D), a defined length of the electronic component (10) is dipped through the coating material (3) continuously rolled on the coating roller (2).

6. The method according to any one of the preceding claims, in, The viscosity of the coating material (3) is between 4000 cP and 10000 cP.

7. The method according to any one of the preceding claims, in, The coating material (3) comprises a polymer.

8. The method according to any one of the preceding claims, in, The coating material composition has a solids weight of between 53.4% ​​and 57.4%.

9. The method according to any one of the preceding claims, in, A plurality of electronic components (10) are coated, wherein respective electronic components (10) include sensor heads (11), and wherein a diameter (D) of the sensor heads (11) of the electronic components (10) varies less than a variation in the diameter of the sensor heads of electronic components coated by conventional coating techniques.

10. The method according to any one of the preceding claims, in, The corresponding electronic component (10) includes an NTC temperature sensor.

11. A coating device (1) for applying a coating (12) to at least one electronic component (10), the coating device (1) comprising a coating roller (2) rotatable about an axis of rotation (R).

12. The coating device (1) according to claim 11, in, The coating roller (2) is adapted and arranged to be wetted with a coating material (3).

13. The coating device (1) according to claim 12, in, The coating material (3) comprises a polymer.

14. The coating device (1) according to any one of claims 11 to 13, Also included is a mounting element (6) for holding at least one of the electronic components (10).

15. The coating device (1) according to claim 14, in, The mounting element (6) is movable along a longitudinal axis (A) perpendicular to the rotation axis (R).

16. A coating device (1) according to claim 14 or claim 15, in, The mounting element (6) is suitable for holding a plurality of electronic components (10).

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