Optical Sheet Edge Spacing for Tab-Free Illuminator Positioning

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Solution Overview

Problem

The existing spread illuminating apparatuses for liquid crystal display devices face challenges in accurately positioning optical sheets without forming tabs, which hinders the narrowing of the frame and can cause uneven brightness due to tab-related issues.

Innovation Solution

The apparatus features a light guide plate with optical sheets where the edge positions on the incident light surface are spaced farther apart as you move towards the top layer, and a light-blocking member extends to cover the edges of the optical sheets, preventing tab formation and ensuring stable fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If tabs are formed on optical sheets for positioning, then positioning accuracy is improved, but frame thickness increases and brightness uniformity deteriorates

Engineering Contradiction:

Improvepositioning accuracyVSAvoidframe thickness

Core Design Contradiction:

Manufacturing precisionVSLength of stationary object

Solution Approach 1:

The invention extracts and eliminates the tab structure from the optical sheets, removing the source of brightness unevenness and frame thickness increase while maintaining positioning accuracy through alternative means (edge spacing configuration)

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of adding tabs to achieve positioning, the invention inverts the approach by positioning optical sheets through controlled edge spacing from the light guide plate, achieving positioning without additional protruding structures

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If tabs are formed on optical sheets for positioning, then positioning accuracy is improved, but brightness uniformity deteriorates

Engineering Contradiction:

Improvepositioning accuracyVSAvoidbrightness uniformity

Core Design Contradiction:

Manufacturing precisionVSIllumination intensity

Solution Approach 1:

The invention extracts and eliminates the tab structure from the optical sheets, removing the source of brightness unevenness while maintaining positioning accuracy through alternative means (edge spacing configuration)

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention applies different edge spacing distances to different optical sheets based on their position in the stack, creating local variations in spacing that prevent tab formation while maintaining positioning accuracy and brightness uniformity

Inventive Principle:

Principle #3Local quality

3Length of stationary object

If frame thickness is reduced to narrow the frame, then device compactness is improved, but positioning accuracy deteriorates

Engineering Contradiction:

Improveframe thicknessVSAvoidpositioning accuracy

Core Design Contradiction:

Length of stationary objectVSManufacturing precision

Solution Approach 1:

The invention transitions from vertical positioning (tabs extending upward) to horizontal positioning (edge spacing from light guide plate), enabling accurate positioning in a thinner frame structure

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS8894264B2Spread illuminating apparatus

Publication Date: 2014.11.25 MINEBEAMITSUMI INC

AI summary

A spread illuminating apparatus includes: a light guide plate with an emitting surface, a plurality of optical sheets laminated on the emitting surface, a light-blocking member that defines an effective area of the emitting surface, a light source, and a frame for accommodating the above constituents. The plurality of optical sheets are formed such that a position of an edge of each optical sheet on the incident light surface side of the light guide plate is spaced farther apart from the incident light surface of the light guide plate as moving toward a top layer of the optical sheets counted from the emitting surface, and the light-blocking member is fixed to each optical sheet and extends from the incident light surface side of the light guide plate so as to cover a vicinity of the edges of the plurality of optical sheets.