1. Multi-phase light-screening agent consists of at least two separate phases, which can be essentially liquid, paste-like and gel-like and which after a brief and gentle mixing process during less than 1 minute and without essential power effect spontaneously separate after a brief time, ranging from several seconds to at least 10 minutes and exist as separate layers, wherein at least one phase contain U/V filter. 2. Light-screening agent according to Claim 1, comprising at least two essentially liquid phases arranged separately, wherein both phases contain at least one U/V filter, and phases after a brief and gentle mixing process are spontaneously separated, remaining corresponding U/V filters in the phase, in which they where originally contain, and phases form separate layers. 3. Light-screening agent according to Claim 2, comprising at least three essentially liquid phases arranged separately, wherein at least two phases contain one U/V filter, and phases after a brief and gentle mixing process are spontaneously separated and form separate layers. 4. Light-screening agent according to any of the preceding Claim, wherein at least one phase is an oily phase, and one of additional phases is not oily and contain perfluorcarbon or a mixture thereof 5. Light-screening agent according to Claim 4, characterized in that the oily phase contain in dissolved or suspended form a lipophile light-screening agent, selected from a plurality of U/V filters which comprise salts of phenylbenzimidazosulfonic acid, salicylic acid ester, benzophen, cinnamic acid ester, benzamalonic ester, estertriazine and dibenzoylmethane derivaties and also dihydroxyacetone preferably selected from group 2-hydroxy- 4 methoxybenziphenone, 2-ethylhexyl- p-methoxycinnamate, natrium-and triethanolaminic salts 2-phenylbenzimidazole-5 sulfonic acid, oxybenzone and dihydrooxyacetone. 6. Light-screening agent according to any of the preceding Claim, wherein the phases do not contain water. 7. Light-screening agent according to any of the preceding Claim, wherein not oily phase contain in dissolved or suspended form hydrophile light-screening agent, selected from a plyrality of U/V filters which comprises titanium dioxide, zink oxide or mixoxide (a) from TiO2 and SiO2 and/or Al2O3or (b) from ZnO and SiO2 and/or Al2O3. 8. Light-screening agent according to Claim 3, comprising 3 phases, wherein phase (A) contains one or several perfluorocarbons and distributed in it as U/V filter non-organic oxide or oxidemix; phase (B) contains polymeric film-forming compound or polymeric lack in an organic solvent, if necessary in mixture with U/V filter; phase (C) contains at least oil for greasing the skin and at least one lipophile U/V filter arranged in it, wherein a portion of phases respective to the general composition is between 15 and 35 wt.%, phase (A), from 5 to 25 wt % phase (B) and from 25 to 80 wt.% phase (C). 9. Light-screening agent according to Claim 8, characterized in that the polymeric lack is shellac 10. Light-screening agent according to Claim 8 or 9, characterized in that additionally comprises phase (D), which contains an oil, different from that in phase (C) and if necessary from lipophile U/V filter.