Touch Display Collimating Openings for Lensless Fingerprint Sensing

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Solution Overview

Problem

Touch display devices face challenges in capturing fingerprint images with desired spatial resolution for reliable optical fingerprint sensing without additional optical collimators.

Innovation Solution

The touch display device incorporates a touch sensing layer with collimating openings that collimate light to photo sensors, allowing for lensless optical design and improved fingerprint image capture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If additional optical collimators are added to improve light collimation for photo sensors, then fingerprint sensing precision is improved, but device complexity and manufacturing difficulty increase

Engineering Contradiction:

Improvefingerprint sensing precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the collimation function from separate optical collimator components and integrates it directly into the touch sensing layer through collimating openings. This eliminates the need for additional optical collimators while maintaining the light collimation function, thereby reducing device complexity while preserving fingerprint sensing precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the collimation function with the touch sensing layer by incorporating collimating openings directly into this layer. This integration combines multiple functions (touch sensing and light collimation) into a single structure, reducing the number of separate components and simplifying the overall device architecture.

Inventive Principle:

Principle #5Merging (Combining)

2Measurement precision

If additional optical collimators are added to improve light collimation for photo sensors, then fingerprint sensing precision is improved, but manufacturing cost and process difficulty increase

Engineering Contradiction:

Improvefingerprint sensing precisionVSAvoidease of manufacture

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent removes the separate optical collimator components from the manufacturing process and extracts only the essential collimation function, implementing it through simple openings in the touch sensing layer. This dramatically simplifies the manufacturing process while maintaining the required fingerprint sensing precision.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive, complex optical collimators with simple, easily manufactured openings in the touch sensing layer. These openings are much cheaper to manufacture and integrate, reducing both material costs and manufacturing complexity while achieving the same functional outcome.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Measurement precision

If the touch sensing layer is made transparent to improve light transmission for fingerprint sensing, then optical fingerprint sensing is enabled, but touch sensing performance may be compromised

Engineering Contradiction:

Improveoptical fingerprint sensing capabilityVSAvoidtouch sensing performance

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent applies local quality by creating specific transparent regions (collimating openings) in the touch sensing layer only where needed for optical fingerprint sensing, while maintaining the integrity and functionality of the touch sensing electrodes and structures in other areas. This localized transparency approach enables optical sensing without compromising overall touch sensing performance.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent segments the touch sensing layer into different functional regions: transparent collimating openings for optical fingerprint sensing and opaque regions with touch sensing electrodes for touch detection. This segmentation allows each region to perform its specific function optimally without interfering with the other.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enables photo sensors to capture fingerprint images with desired spatial resolution for reliable optical fingerprint sensing without requiring additional optical collimators.

Implementation Method 1

a plurality of first collimating openings positioned between the touch sensors and corresponding to the plurality of photo sensors respectively to collimate light from different locations to the plurality of photo sensors

Methodology Applied

Scientific EffectLight collimation: Lens

Implementation Method 2

a plurality of fingerprint devices coupled with the plurality of photo sensors, wherein the fingerprint device senses output of the plurality of photo sensors for controlling sensing operation of the photo sensors to generate fingerprint sensing signals

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Data Source

PatentUS11733792B2Touch display device

Publication Date: 2023.08.22 NOVATEK MICROELECTRONICS CORP

AI summary

A touch display device includes a plurality of photo sensors, a plurality of display pixels, and a touch sensing layer. The touch sensing layer disposed over the plurality of photo sensors and including a plurality of collimating openings corresponding to the plurality of photo sensors respectively to collimate light from different locations to the plurality of optical sensors.