Is past perfect the same as past participle? Is the past perfect tense has + (word)ed? Does the past participle always have a helping verb?
The bored students went into sleep during the boring lecture, in this sentence you can see, "bored" needs not any helping verb, it is an example of a past participle.
But what is a participle I mean present and past that is a bit detail answer. I have many answers in this issue, please find them out from my profile.