Patent Application
20230326635
The present invention relates to a thin film resistor, in particular to a thin film resistor with high heat dissipation efficiency.
A general resistor structure usually includes a rectangular insulating substrate, two electrodes arranged on both sides of the surface, and a resistance layer is arranged on the surface of the substrate between the two electrodes and connected with the two electrodes.
In the resistance adjustment process, the resistance layer is irradiated with laser light to repair and/or adjust the resistance.
The temperature peak locates at the center and gradually decreases to the electrodes for conventional resistor. The heat dissipation path is too long to reduce the heat dissipation efficiency.
In order to solve the above-mentioned problems, the present invention uses a specific pattern of the resistance layer to shift the temperature peak from the center to the ends close to the electrodes. Therefore, the heat dissipation path is reduced.
The invention provides a thin film resistor, and the resistance layer of the film resistor has a mesh pattern. In one embodiment, the mesh pattern includes two mesh densities. The mesh density of the pattern is high near the center of the resistor and low near both electrodes.
The present invention provides a thin film resistor, and the resistance layer of the film resistor has a mesh pattern with a various mesh density. The mesh density increases from the center to both ends of the film resistor.
Various embodiments of the present invention will be described in detail as below, and the drawings will be used as examples to help readers to have a better understanding. In addition to these detailed descriptions, the present invention can also be widely implemented in other embodiments. Any substitutions, modifications, and equivalent changes of the embodiments should be understood to be included in the scope of the present invention. The scope of patents should be based on the scope of the claims. It should be noted that the drawings are for illustrative purposes only, and do not represent the actual size or quantity of the components. Some details may not be completely drawn in order to keep the drawings concise.
The present invention provides a thin film resistor. Both ends of the film resistor are electrodes, and a resistance layer on the substrate is between electrodes and connected the electrodes. The resistance layer is formed to have a mesh pattern. In one embodiment, the mesh pattern comprises connected multiple mesh portions and different mesh portion has different mesh density. In one embodiment, the mesh pattern has a mesh density varies with the position on the film resistor. The mesh pattern can be formed by lithographic etching. The mesh density is high (i.e. fine mesh) near the electrodes and low (coarse mesh) near the center of the film resistor, and the area covered by the coarse mesh is larger than that covered by the fine mesh. Such design distributes the thermal focus from the center to both ends of the film resistor. As a result, the length of the dissipation path is reduced to have a better heat dissipation efficiency.
In one embodiment, the area covered by the second mesh portion 122 is smaller than that covered by the first mesh portion 121. The area covered by the second mesh portion 122 is 50˜75% of that covered by the first mesh portion 121 area.
Preferably, the wire width W2 of the second mesh portion 122 is 50˜75% of the wire width W1 of the first mesh portion 121.
Preferably, the distance D2 between the electrode 11 and the second mesh portion 122 is 50˜75% of the distance D1 between the first mesh portion 121 and the second mesh portions 122.
In this embodiment, the area covered by the first mesh portion 121, the second mesh 122 and the third mesh 123 decreases gradually with a ratio 50˜75%.
Preferably, the mesh width W1 of the first mesh portion 121, the width W2 of the second mesh portion 122, and the width W3 of the third mesh portion 123, also decreases gradually with a ratio 50˜75%.
Preferably, the distance D3 between the electrode 11 and the third mesh portion, the distance D4 between the third mesh portion 123 and the second mesh portion 122, and the distance D2 between the second mesh portion 122 and the first mesh portion 121, also decrease gradually with a ratio 50˜75%.
In the above embodiment, the first mesh portion 121, the second mesh portion 122 and the third mesh portion 123 are rectangular, and the mesh is also rectangular. Preferably, the area covered and/or wire width of the first mesh portion 121, the second mesh portion 122 and the third mesh portion 123 varies with a ratio 4:2:1.
Obviously, the mesh density gradually increases from the center to the electrode, and the two adjacent mesh portions are getting closer. When the current passes through, the temperature distribution variation is positively related to the mesh density and the thermal peaks are distributed, and the maximum peak will be adjacent to the electrodes to have a better heat dissipation.
The substrate material is aluminum nitride, and the electrode material is copper. Both have high thermal conductivity. The mesh pattern design can enhance the heat dissipation rate.
The mesh resistance layer of the thin film resistor can decrease the temperature near the center and increase the temperature near the electrodes. However, the shifted temperature peak is adjacent to the electrodes to have a shorter dissipation path and a better heat dissipation efficiency. Therefore, the whole temperature of the film resistor is decreased and the temperature distribution is homogenized in the mean while.
| Number | Date | Country | Kind |
|---|---|---|---|
| 111112986 | Apr 2022 | TW | national |
