Light Guide Recesses Manage Paste Thermal Stress

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Solution Overview

Problem

Display panels experience image sticking due to thermal expansion and contraction of paste materials between the circuit board and light guide structure, especially in high-temperature and high-humidity environments, which existing technologies fail to prevent effectively.

Innovation Solution

The display device incorporates a light guide structure with plating pads on its bottom surface and corresponding recesses on its peripheral surface, allowing paste materials to deform without causing stress concentration, as the recesses function as springs to manage thermal expansion and contraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If paste materials are used to electrically connect the circuit board and light guide structure, then electrical connection is achieved, but thermal expansion and contraction cause deformation and image sticking

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidpaste material stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent designs the light guide structure with recesses (first recesses on peripheral surface, second recesses on bottom surface) that act as cushioning spaces for the paste materials. These recesses allow the paste materials to deform inward during thermal expansion and contraction without generating harmful stress, thereby preventing image sticking while maintaining electrical connection reliability

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent changes the physical state and spatial configuration parameters of the paste materials by providing dedicated recesses in the light guide structure. The paste materials transition from a constrained state to a state with controlled deformation space, allowing thermal expansion and contraction to occur within the recesses rather than causing external stress on the display panel

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the paste materials are rigidly fixed between the circuit board and light guide structure, then stable electrical connection is achieved, but stress concentration occurs during thermal changes

Engineering Contradiction:
Improveelectrical connection stabilityVSAvoidstress concentration in paste materials
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The light guide structure incorporates first recesses on its peripheral surface and second recesses on its bottom surface, creating predetermined deformation zones. These recesses cushion the paste materials during thermal expansion and contraction, preventing stress concentration while maintaining stable electrical connection between the circuit board and light guide structure

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If the light guide structure is made rigid for structural stability, then structural strength is improved, but thermal expansion and contraction cause image sticking

Engineering Contradiction:
Improvelight guide structure strengthVSAvoiddisplay panel reliability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The light guide structure maintains overall structural rigidity while incorporating localized recesses (first recesses on peripheral surface, second recesses on bottom surface) that provide deformation space for paste materials. This local modification allows the structure to remain strong while preventing stress transmission to the display panel during thermal cycles

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The recesses in the light guide structure serve as pre-designed cushioning zones that accommodate thermal expansion and contraction of the paste materials. This prevents stress concentration and image sticking while maintaining the overall structural integrity and strength of the light guide structure

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 design effectively reduces stress concentration in the paste materials, preventing image sticking on the display panel by allowing the plating pads to move with thermal changes, thus enhancing the panel's durability and reliability in varying environmental conditions.

Implementation Method 1

the first recesses and corresponding to the two plating pads and the second recesses on the bottom surface and adjacent to the two plating pads. When the paste materials deform, the first recesses function as a spring, such that the plating pads can be pulled down as the paste materials contract and the plating pads can be lifted up as the paste materials expand.

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3086171B1Display device
Publication Date: 2018.03.14 HIMAX DISPLAY INC
  • EP3086171B1 patent drawingFigure 1
  • EP3086171B1 patent drawingFigure 2
  • EP3086171B1 patent drawingFigure 3

AI summary

A display device (3, 3') includes a display panel (30), a circuit board (32), a light guide structure (34, 34') and two paste materials (36). The circuit board (32) is disposed on the display panel (30). The light guide structure (34, 34') is disposed on the display panel (30). The light guide structure (34, 34') has a bottom surface (340) and a peripheral surface (342), wherein the bottom surface (340) is oriented toward the display panel (30) and the peripheral surface (342) is adjacent to the bottom surface (340). Two plating pads (344) are formed on the bottom surface (340). Two first recesses (346) are formed on the peripheral surface (342) and corresponding to the two plating pads (344). The two paste materials (36) are formed between the two plating pads (344) and the circuit board (32).