Optical Sheet Asymmetric Prisms Reduce Contact Defects

Solution Overview

Problem

Conventional optical sheets with linearly-extending unit prisms face issues when superimposed, leading to problems like bright spots, stripe patterns, and wetting patterns due to direct light passage and contact with adjacent members, which are not fully resolved by existing solutions that either increase production costs or compromise image quality.

Innovation Solution

An optical sheet with unit prisms having an uneven polygonal-line-shaped contour, where the distance between the top of each raised portion and the body portion is not constant, and the unit prisms are arranged in a direction intersecting the arrangement direction, reducing contact area and preventing issues like direct passage of light and wet-out.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If conventional optical sheets with linearly-extending unit prisms are used, then front direction luminance is enhanced, but contact with adjacent members causes bright spots, stripe patterns, and wetting patterns

Engineering Contradiction:

Improvefront direction luminanceVSAvoidcontact-related optical defects

Core Design Contradiction:

Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent applies asymmetry by changing the symmetric isosceles triangular prism shape to an asymmetric shape where the apex angle differs from 90 degrees. This asymmetric configuration prevents uniform contact with adjacent members, reducing the formation of bright spots, stripe patterns, and wetting patterns while preserving light condensing functionality.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent applies local quality by varying the apex angles of different unit prisms within the optical sheet. Specifically, some unit prisms have apex angles of 80-90 degrees while others have 90-100 degrees. This local variation in prism geometry creates non-uniform contact characteristics across the sheet surface, preventing systematic optical defects while maintaining overall light condensing performance.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If unit prisms have uniformly varying heights to reduce contact area, then contact problems are reduced, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvecontact areaVSAvoidproduction cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent applies local quality by varying the apex angles of different unit prisms within the optical sheet. Specifically, some unit prisms have apex angles of 80-90 degrees while others have 90-100 degrees. This local variation in prism geometry creates non-uniform contact characteristics across the sheet surface, preventing systematic optical defects while maintaining overall light condensing performance.

Inventive Principle:

Principle #3Local quality

3Object-affected harmful factors

If unit prisms have non-constant height variations, then contact area is reduced and optical defects are minimized, but manufacturing precision requirements increase

Engineering Contradiction:

Improveoptical defect preventionVSAvoidprism height consistency

Core Design Contradiction:

Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the apex angles of different unit prisms within the optical sheet. Specifically, some unit prisms have apex angles of 80-90 degrees while others have 90-100 degrees. This local variation in prism geometry creates non-uniform contact characteristics across the sheet surface, preventing systematic optical defects while maintaining overall light condensing performance.

Inventive Principle:

Principle #3Local quality

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

The optical sheet effectively enhances front direction luminance and reduces contact-related problems, maintaining optical performance while minimizing production costs and image distortion.

Implementation Method 1

an optical sheet having a function (light condensing function) to change the travel direction of light so that the angle (exit angle) between the direction of the exiting light and the front direction becomes smaller, thereby enhancing the front direction luminance

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

each unit prism, when viewed in a direction parallel to the arrangement direction of the unit prisms, has an uneven polygonal-line-shaped contour

Methodology Applied

Scientific EffectLight scattering: Scattering

Data Source

PatentUS9423537B2Optical sheet, surface light source device, transmission type display device, light emitting device, mold and mold production method

Publication Date: 2016.08.23 DAI NIPPON PRINTING CO LTD

AI summary

An optical sheet includes a sheet-like body portion, and unit prisms arranged on one surface of the body portion. Each unit prism extends linearly in a direction intersecting the arrangement direction. Each unit prism, when viewed in a direction parallel to the arrangement direction of the unit prisms, has an uneven polygonal-line-shaped contour and, with reference to raised portions defined by the polygonal-line-shaped contour of each unit prism, the distance between a top of each raised portion, a farthest point from the body portion in the raised portion, and the body portion in the normal direction of the body portion is not constant. The optical sheet can prevent significant problems when it is superimposed on another member.