Oppo has filed a request with the EUIPO to trademark more than 20 variants of its mid-range K-series smartphones. 

Among the registration requests are the pre-existing K1 and K3 models, but all of the others - so far - are unreleased. 

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The patents were found by LetsGoDigital, a site with a growing reputation for unveiling Oppo's plans in Europe. 

One thing that isn't clear, despite this huge number of trademark requests, is just how many of them are in the works, or will even be released anytime in the short, or even long-term future.

From the pattern of registration it appears as though Oppo is covering all of its bases, so that when it comes time to launch more K-series phones, it has a swathe of names to choose from that it knows it can use in Europe officially. 

Among the patents are K2, K5, K5, K6, K7, K8, K9, K12 and K13, with others from K20-K100 in increments of 10. 

The K-series, for all intents and purposes, is Oppo's answer to Honor phones. They offer a nice looking design, big screens and mid-range processors for a very affordable price.

For instance, the Snapdragon 710-powered K3 announced in May costs around €210 in Europe. 

With that said, it does make the lines between itself and some of the other Oppo phones very blurry indeed. 

Oppo has no shortage of mid-range phones that look fairly similar. Devices like the F11 Pro, and some of the A-series in the company's lineup seem to compete with each other to some degree. 

Some of this - of course - is down to different phones being available in different markets. And with Oppo having only relatively recently landed in the UK and mainland Europe, it makes sense to diversify its handset portfolio to include products Europeans will be drawn to.