U.S. special envoy Philip C. Habib left Israel for the United States today after a series of talks here that produced glimmers of new flexibility by the Israelis but little concrete progress toward an Israeli troop withdrawal from Lebanon.

Asserting Israel's openness to "new ideas" to break the deadlock, a senior official told reporters today that Israel is "ready to consider seriously" a proposal that instead of permanent Israeli-manned observation posts in southern Lebanon the area be policed by joint Lebanese-Israeli army patrols large enough and with enough arms to fight any Palestinian guerrillas they encounter.

"But I have to stress that such a proposal has not been made to us," the Israeli official said.

Habib met briefly with Foreign Minister Yitzhak Shamir this morning for what was described as a review of the status of the negotiations. Israeli officials said Habib is expected back in the Middle East in about a week after consultations with administration officials in Washington.

As Habib's latest trip to Israel ended, the main sticking points in the troop withdrawal talks remained essentially unchanged. They are Israel's demands for the establishment of "normal relations" between the two countries and for the right to station Israeli soldiers at observation posts inside a 25- to 30-mile-deep security zone in southern Lebanon in return for withdrawing the bulk of its forces.

The Lebanese are resisting both demands and made their own counterproposals, which were conveyed to the Israelis this week by Habib. The Israelis turned them down but made clear their willingness to consider other compromise proposals on both of the issues.

The Israelis appear to be especially eager to find a way around the issue of the Israeli-manned outposts. This is a demand that was most forcefully pressed by former defense minister Ariel Sharon, who argued that only Israeli soldiers would have the skills and motivation needed to prevent reinfiltration of southern Lebanon by Palestine Liberation Organization guerrillas.

But this would leave Lebanon in the position of agreeing to a residual Israeli presence in the southern part of the country while still seeking a complete Syrian and Palestinian withdrawal from the east and the north, which Israel is also demanding.

In apparent recognition of the obstacles posed by the observation posts issue, Israeli officials reiterated today their willingness to consider any ideas that they think would be as effective in safeguarding Israel's northern border from guerrilla attack.

"The technical side of how we achieve it is less important than the results," an official said in discussing possible joint patrols.

According to the Israelis, Lebanon's latest proposal on the issue, conveyed by Habib this week, was for joint Lebanese-Israeli "supervisory teams" that would periodically inspect the security zone. But the Israelis told Habib that such presumably small teams are "not good enough" because, unlike the joint patrols Israel says it is willing to consider, they would lack the manpower and weapons to fight guerrillas.

Joint patrols would still pose serious problems for the Lebanese, requiring them to give regular access to large parts of their territory to soldiers from a neighboring country.

But since the Israeli soldiers would be stationed in Israel when not on patrol, this solution would have the advantage of not requiring a permanent Israeli presence.

The other major sticking point in the talks--Israel's demand for "normal relations" with Lebanon--was also the subject of a compromise proposal conveyed to Israel by Habib. Under it, according to officials here, a troop withdrawal would be followed by an interim period of "temporary arrangements" involving the passage of goods and people across the border but without a formal agreement to that effect.

During the interim period of about six months, negotiations would resume on a permanent agreement for normalization of relations between the two countries.

Israel turned down the suggestion, but officials said they were willing to reconsider it if Lebanon provided details of what it envisages as the temporary arrangements. Lebanon, fearful of retaliation by other Arab states should it agree to normal relations with Israel, apparently hopes to delay if not avert signing a formal agreement with Israel while nonetheless acceding to Israeli demands for the free flow of goods and people across the border.

Israeli officials say they are willing to allow Lebanon to call the arrangement anything it likes, but they insist that the substance of these "temporary arrangements" amounts to the same thing as formal normalization and that it not be left vague as the Israelis say the Lebanese have proposed.

Washington Post correspondent Herbert H. Denton reported from Beirut:

Lebanese Foreign Minister Elie Salem expressed optimism today about the progress of Israeli troop withdrawal negotiations but he said that Israel's demands for normal relations remained one of the principal stumbling blocks in the talks.

Salem, speaking at a press conference for American reporters, said, "If Lebanon errs in this area, Lebanon can lose its existence, its being." He added that "we are not going to close 22 frontiers to open one frontier."

Lebanon fears that agreement now to normal relations with Israel might spark a new round of civil warfare and could cause other Arab states, which constitute 95 percent of Lebanon's export market, to break relations, Salem said.