Fingerprint Sensor on Flexible Substrate for Touch Panel

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Solution Overview

Problem

Conventional fingerprint identification technologies in electronic devices suffer from poor sensitivity due to the distance between fingerprint sensor chips and fingers, and the large space occupation by these chips.

Innovation Solution

A touch panel with a fingerprint identification function is developed, where a fingerprint sensor array is disposed on a flexible substrate, reducing the distance to the user's fingers and utilizing a cover plate with recesses to further minimize this distance, thereby enhancing sensitivity and reducing space occupation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fingerprint sensor chip module is used for fingerprint identification, then fingerprint detection function is achieved, but the sensor occupies too much space and transducers are disposed far away from fingers resulting in poor sensitivity

Engineering Contradiction:

Improvefingerprint identification sensitivityVSAvoidspace occupied by fingerprint sensor chip module

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent divides the fingerprint sensor chip module into separate components: transducers are separated from the chip module and directly disposed on the cover plate, while the chip module itself is minimized or integrated differently. This segmentation allows the transducers to be positioned closer to the finger surface without requiring a large chip module structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent transitions from a three-dimensional chip module structure to a two-dimensional arrangement where transducers are directly disposed on the cover plate surface. This dimensional change eliminates the need for a bulky chip module housing while maintaining the fingerprint sensing function, thereby reducing the occupied space.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If a fingerprint sensor chip module is used for fingerprint identification, then fingerprint detection function is achieved, but transducers are disposed far away from fingers resulting in poor sensitivity

Engineering Contradiction:

Improvefingerprint identification sensitivityVSAvoiddistance between transducers and fingers

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

The patent extracts the transducers from the fingerprint sensor chip module and directly mounts them on the cover plate. This extraction eliminates the intermediate structure (chip module housing) that created distance between the transducers and the finger surface, thereby improving sensitivity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses a thin cover plate structure to which transducers are directly attached. This thin-film approach minimizes the distance between the transducers and the finger surface, enabling high sensitivity fingerprint detection without requiring a bulky chip module structure.

Inventive Principle:

Principle #30Flexible shells and thin films

3Reliability

If fingerprint sensor chip module is used, then fingerprint detection is achieved, but it occupies too much space in the electronic device

Engineering Contradiction:

Improvefingerprint detection capabilityVSAvoidspace occupied by fingerprint sensor chip module

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent merges the transducer assembly with the cover plate structure, eliminating the need for a separate fingerprint sensor chip module housing. By combining these functions into a single integrated structure, the overall volume required for fingerprint sensing is significantly reduced.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent transitions from a three-dimensional chip module to a two-dimensional planar arrangement where transducers are disposed directly on the cover plate surface. This dimensional reduction eliminates the vertical height requirement of a chip module, thereby reducing the volume occupied by the fingerprint sensing system.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10514798B2Touch panel with fingerprint identification function and method for fabricating the same

Publication Date: 2019.12.24 ALPHA TOUCH GROUP LLC

AI summary

A touch panel with a fingerprint identification function includes a cover plate, a mask layer, a flexible substrate, and a fingerprint sensing array. The mask layer is disposed on the cover plate for defining an operating region and a non-operating region of the touch panel. The flexible substrate is disposed on the mask layer and at least in the non-operating region. The fingerprint sensing array is directly disposed on the flexible substrate in the non-operating region. Through the configuration that the fingerprint sensing array is disposed on the flexible substrate, the distance between the fingerprint sensing array and a user's fingers is reduced, thereby increasing the sensitivity of fingerprint identification.