Optical Module Thickness Reduction via Integrated Collimator Design

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Solution Overview

Problem

The existing optical modules in mobile terminals, such as fingerprint modules, occupy a large space due to the thickness of adhesives and substrates, which increases the overall size and reduces signal strength and photosensitivity efficiency.

Innovation Solution

The photosensitive unit and wiring structure are directly formed on the surface of the collimator, eliminating the need for adhesives and a bearer substrate, thereby reducing the optical module's thickness and enhancing signal strength and photosensitivity by minimizing the distance to the display screen.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the photosensitive unit and wiring structure are bonded to the collimator through adhesive and bearer substrate, then the structural integrity is maintained, but the thickness of the optical module increases

Engineering Contradiction:
Improvethickness of optical moduleVSAvoidstructural integrity
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent merges the collimator, photosensitive unit, and wiring structure into a single integrated component. The photosensitive unit and wiring structure are directly formed on the surface of the collimator through printing and sintering processes, eliminating the need for separate adhesive layers and bearer substrates. This integration reduces the overall thickness while maintaining structural integrity through direct material bonding.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates the adhesive layer and bearer substrate from the traditional optical module structure. By removing these intermediate components, the design achieves direct contact between the photosensitive unit/wiring structure and the collimator, thereby reducing thickness without compromising functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

2Strength

If the adhesive layer thickness is increased to ensure bonding strength, then the structural stability is improved, but the space occupied by the optical module increases

Engineering Contradiction:
Improvebonding strengthVSAvoidspace occupied by optical module
Core Design Contradiction:
StrengthVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical adhesive bonding system with a direct sintering-based bonding system. The wiring structure and photosensitive unit are formed by printing conductive paste and sintering it directly onto the collimator surface, creating a metallurgical or ceramic bond that eliminates the need for thick adhesive layers while maintaining or improving bonding strength.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the distance between the photosensitive unit and display screen is reduced, then the signal strength is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improvesignal strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple manufacturing steps into an integrated process. The collimator, photosensitive unit, and wiring structure are manufactured as a single component through a unified printing and sintering process, which simplifies the overall manufacturing complexity despite achieving reduced distances and improved signal strength.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces the optical module's thickness by 0.13 mm to 0.2 mm, increases signal strength, and improves user experience by enhancing photosensitivity efficiency and reliability of connections.

Implementation Method 1

a first end of the light guide is provided with a reflective layer, the reflective layer and the optical component are respectively located at two sides of the first optical component in a projection direction along a light transmission direction of the light guide, a projection of the first optical component onto the light guide along the light transmission direction overlaps with a projection of the reflective layer onto the light guide along the light transmission direction, and a light transmitting surface of the optical component faces a display panel

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3992843B1Optical module and mobile terminal
Publication Date: 2024.05.29 VIVO MOBILE COMM CO LTD
  • EP3992843B1 patent drawingFigure 1~2

AI summary

The present disclosure discloses an optical module and a mobile terminal. The optical module includes a collimator, a photosensitive unit, and a wiring structure, wherein the photosensitive unit is arranged on a surface of one side of the collimator, and the wiring structure is arranged on a surface of one side, away from the collimator, of the photosensitive unit.