The beleaguered U.S. Patent Office, short-handed and long criticized, has been given new hope by what its commissioner calls the most important patent legislation in decades.

The new law -- if it lives up to the commissioner's expectations (and not everyone agrees that it will) -- comes none too soon for the troubled agency. It has been losing 50 to 75 percent of the court challenges brought against its patents, and is being attacked by courts and inventors alike as being willing to patent devices so simple or trival that they hardly seem worthy of the name "invention."

The key to the Patent Office's difficulties has been its limited staff and rising workload.

Under current procedures, each new application for a patent is referred to an examiner, who searches the relevant categories among the roughly 4 million patents on file and decides if the device is really new. But since they are about 100,000 applications each year and only a thousand examiners, the time devoted to the search is usually small -- about 15 hours.

Therefore, it has been fairly easy for someone who wants to challenge a patent to do a better search and find some record indicating that the device is not new and not patentable.

Since a patent grants an inventor a 17-year monopoly on his or her invention, invalidating a patent can prove a relatively inexpensive way for a would-be competitor to get into the market.

Although the law states that a patent is "presumptively valid," challengers commonly point to the Patent Office's limited search as evidence against such a presumption. And courts have often agreed.

The revised law takes this lever away. It allows anyone involved in a challenge -- the court, the challenger or the patent holder -- to have the case referred back to the Patent Office for reexamination. When this happens, the Patent Office not only gets a second shot at the case, but also the benefit of all the new research done by the challenger.

This, say patent lawyers, will not only allow the Patent Office to retrieve some bad cases, and improve its batting average in court, but will also allow weak cases or marginally "new" inventions to become much more defensive in court.

Patent Commissioner Sidney Diamond says that the percentage of patents invalidated is not representative because he believes that only those patents that look vulnerable are challenged. "But having said that, we do recognize that it is a problem that half of these challenged patents are held invalid," he said.

The commissioner said he doesn't believe that the new law will discourage those who want to challenge a patent. "There probably will be no effect on that," he said. "But one of the great advantages of the law is that it will remove some of the criticism that has been leveled at the whole patent system. Right now, once you get into court on a patent, you are talking about hundreds of thousands of dollars and years of time.

"We expect that in the majority of cases where validity is involved, this would no longer be necessary," Diamond said. Many of the cases may be settled instead of being dragged through court, and sometimes, Diamond expects that the original patent will be voided when it is brought back for reexamination.

The law, which finally made it through Congress last year, was written and lobbied hard by the trade group of patent lawyers, the National Patent Law Association. Some patent lawyers have been seeking a law of this type for 40 years, at least one lawyer can recall.

In the past the Justice Department has opposed such a law on the grounds that relatively fewer, higher quality patents should be issued, and that a reexamination law would favor the survival in court of more marginally new inventions. But under the Carter administrtation, the Justice Department changed its tune when officials became concerned that flagging innovation in the United States might be attributable in some measure to the clogged patent system.

Now that the bill is law, some doubt Commissioner Diamond's assessment of how it will work.

Patent attorney Robert LeBlanc, of LeBlanc, Nolan, Shur, & Nies, said, "I think on the whole it will cause the Patent Office to fall even farther behind. It will slow things down tremendously. It means more work for the patent examiners, and nobody is scheduling one extra penny for it."

LeBlanc also said he thought it would make patent defense a much more costly procedure. He said reexaminations by the Patent Office might take two years or more, as the few allowed by law in the past have done. "And this will increase the cost, not decrease it. It means extra proceedings, contested proceedings" for which more lawyers hours will be required.

Patent attorneys Edward Irons and Mary Helen Sears argue a further negative effect of the law. "The patentability standard of the Patent Office is very low, lower than the standard of the district court and the Supreme Court . . . but this new law will increase the survivability in court of patents issued under the very low standard of the Patent Office," said Irons.

The Patent Office will now get a look at all the new information brought into court by a challenger before making its second and likely final decision to issue a patent Thus, the patent's "presumptive validity" under law will be harder to challenge by the usual method of offering new evidence or "prior art," as the patent lawyers call it. More patents, therefore, including seemingly simple and inconsequential "inventions," will survive challenges.

This means that a continuing and even larger glut of marginally new products will get patents, and get 17-year monopolies in the marketplace, Irons said, and quoted the Supreme Court: "It was never the object of those laws to grant a monopoly for every trifling device" because "such an indiscriminate creation of exclusive privileges tends to obstruct rather than stimulate invention. It creates a class of speculative schemers who make it their business to" take advantage of every small change in a product to gain a monopoly on its sale.

One example of the sort of "trifiling device," Irons said, was a capped funnel intended to be put on top of an oil can to make pouring and saving oil easier. The funnel seems simple enough, and the Patent Office found several similar devicers in its files. But the inventor, Robert Nowak, went back and fourth with the Patent Office several times, trying to modify the device in such a way as to make something about it new.

Finally, a tiny flange, or bump, was added at the bottom of the funnel to help hold it onto the oil can. This, the Patent Office said, was new and the patent was issued.

When someone else wanted to make funnels for oil cans, the patent was challenged. During the case, the challenger found other instances of patent funnels with differing combinations of all the various bumps, caps, and so on, that Nowak's funnel had.

Finally the court held that the "invention," bumps or no, was an obvious development and therefore could not be patented. According to law, an invention must not be obvious to a person skilled in the art or manufacture of similar things.

Commissioner Diamond conceded that sometimes patent examiners make mistakes, and obvious developments get patents. "I don't know whether this funnel thing was a mistake or not, but it's just one case," he said.

"Some inventions are more trivial than others, of course. And sometimes something that looks trivial to you or me may turn out to have great commerical value," he said. "Somebody might come up with a new kind of paper clip that is not obvious. It could be a boon to mankind."