Can a technical scheme be used to apply for invention patents in different technical fields?

Of course. The examination of inventions is subjective (the examiner's subjective). To apply for a technical scheme in different technical fields, it is necessary to have certain differences in the above-mentioned different technical fields, and to apply on the same day to confirm that there is no direct and obvious mutual promotion relationship between the schemes. We can't let the examiner think that the essence is the same and we can't convince the examiner.