Apple CEO Tim Cook attends the 'Wonderlust' event at the company's headquarters in Cupertino, California, on Tuesday. Reuters

Apple on Tuesday unveiled a new iPhone 15 with a brighter display and a 48-megapixel camera as well as 100% recycled cobalt in its battery, amid a global smartphone slump and problems with sales in China.

The event at Apple's Cupertino, California, headquarters comes amid lingering economic uncertainty, especially in China, Apple's third-largest market where it faces challenges from expanded restrictions on using its iPhones in government offices and the first new flagship phone in several years from Huawei Technologies.

Apple also showed off a new Series 9 Watch with a feature called "double tap" where users tap thumb and finger together twice, without touching the watch, in order to perform tasks like answering a phone call.

It uses machine learning to detect tiny changes in blood flow when the user taps their fingers together, freeing up the other hand for other tasks like walking a dog or holding a cup of coffee, said Apple Chief Operating Officer Jeff Williams.

The Apple Watch Ultra 2 has new features for cycling and diving and what Apple said is the brightest screen it has ever made.

Apple will no longer use leather in any of its products, said Lisa Jackson, the company's environmental chief. The company is replacing some of those products with a textile called "FineWoven" that it says feel like suede.

CEO Tim Cook also said Apple is "on track" to ship its Vision Pro mixed-reality headset early next year.

While Apple is introducing new features and products, the iPhone made up more than half of Apple's $394.3 billion in sales last year.

The global smartphone market has slumped from shipping 294.5 million total phones to 268 million in the second quarter, but Apple's shipments declined the least of any major smartphone maker, dropping from 46.5 million phones to 45.3 million, according to data from Counterpoint Research.

"The truth of the matter is, we're in a very down smartphone market," said Bob O'Donnell, head of TECHnalysis Research.

O'Donnell said he will also be on the lookout for any hints about Apple's plans with what is known as generative artificial intelligence, the technology trend behind applications like OpenAI's ChatGPT and Microsoft's "Copilot" assistant technologies for its Office software.

Analysts have repeatedly prodded Apple about its plans for such technology but the company has given few hints so far, other than Chief Executive Tim Cook's comments in July that the company's secret work on the technology is driving up its research spending.

"Will Apple tease an advanced form of Siri? That would be something that would generate some excitement," O'Donnell said.

Reuters