Apple has filed a series of patents over the years relating to different approaches to delivering Under-Display Touch ID (01, 02, 03, 04, 05, 06 and 07). Several rumor-gurus have forecast and re-forecasted it's arrival for a few years now. Apple will of course release it when the technology has proven to meet their standards, whenever that is. Today the U.S. Patent and Trademark Office officially granted Apple a technical patent relating to an optical-fingerprint detection system.  

Apple notes in their granted patent that an optical fingerprint sensor may be particularly advantageous for verification and/or authentication in an a portable device such as an iPhone.

In some implementations, the temperature compensation method is a row-based scheme. In the row-based scheme, the one or more pixels of the array are pixels of a row of the array, and the first reading is acquired while corresponding pixel switches are open. The second reading is acquired while corresponding pixel switches are closed.

In one or more implementations, the temperature compensation method is a blind pixel scheme. In this scheme, the one or more pixels of the array include entire pixels of the array. Pixels of one or more columns of the array are blind pixels that are shielded from optical exposure. In the blind pixel scheme, the first reading acquired by a first row-based double sampling for blind pixels, and the second reading is acquired by a second row-based double sampling for exposed pixels.

In some implementations, the temperature compensation method is a frame-based scheme, in which the one or more pixels of the array include entire pixels of the array. In this scheme, the first reading is acquired by using a first frame-based double sampling while the array is not illuminated, and the second reading is acquired by using a second frame-based double sampling while the array is illuminated. In one or more implementations, the temperature compensation method is a combination of the row-based scheme, the blind scheme and the frame-based scheme.

Apple's patent FIG. 11 below illustrates an overview of a future iPhone that will include an optical-fingerprint detection system; FIG.  FIGS. 2A through 2C are diagrams illustrating example schemes for temperature compensation in an optical-fingerprint detection system.

If correct, this is the first optical-fingerprint detection system patent that discusses the use of a  temperature compensation method.  For more details, review Apple's granted patent 11636702.

Apple Inventors

• Moe (Mohammad) Yeke Yazdandoost: Tech Lead – Lead Sensing Systems Architect
• Chris Krah: Senior HW Engineer