Edge Luminance Uniformity in Video Display Devices

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional video display devices using lenses for light diffusion face challenges with luminance lowering and non-uniformity at the edges of the display panel, particularly due to the increased complexity and accuracy required in positioning multiple lenses as the number of light sources increases.

Innovation Solution

A video display device configuration that employs a single optical member, such as a flatter, between the display panel and light source substrates, combined with a reflection sheet that extends beyond the optical member's edge, to uniformly distribute light and reduce luminance issues at the edges.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple lenses are provided on each light source to diffuse light, then luminance uniformity is improved, but device complexity and positioning difficulty increase

Engineering Contradiction:

Improveluminance uniformityVSAvoidnumber of optical components

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

Multiple separate lens components are merged into a single integration-type optical member that covers multiple light sources. This reduces the total number of components and simplifies positioning while maintaining the light diffusion function needed for luminance uniformity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The integration-type optical member serves multiple functions: it acts as a diffusion element for multiple light sources, provides structural support, and defines the light emission area boundary. This multi-functionality reduces the need for separate components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Manufacturing precision

If multiple lenses are provided on each light source to diffuse light, then luminance uniformity is improved, but positioning accuracy requirements increase

Engineering Contradiction:

Improveluminance uniformityVSAvoidpositioning accuracy

Core Design Contradiction:

Manufacturing precisionVSMeasurement precision

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

3Use of energy by moving object

If a reflection sheet is positioned exactly at the optical member edge, then light reflection efficiency is improved, but luminance uniformity at panel edges deteriorates

Engineering Contradiction:

Improvelight reflection efficiencyVSAvoidluminance uniformity at panel edges

Core Design Contradiction:

Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The reflection sheet is designed with different positional relationships relative to the optical member edge: it extends beyond the optical member edge in some regions to provide additional light reflection to edge areas, while maintaining appropriate positioning in other regions. This local variation in positioning creates different reflection characteristics for different areas.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The reflection sheet is positioned asymmetrically relative to the optical member, extending beyond the edge on one side more than others. This asymmetric positioning compensates for the non-uniform light distribution that occurs at panel edges, providing enhanced reflection where needed.

Inventive Principle:

Principle #4Asymmetry

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 simplifies the positioning process and effectively reduces luminance lowering and non-uniformity at the edges of the display panel by allowing easier placement of light sources and reflection of light towards the center, enhancing luminance uniformity with a reduced number of components.

Implementation Method 1

a reflection sheet that is provided on the main surface of the light source substrate... The reflection sheet extends to an outside of an outer peripheral edge of the optical member

Methodology Applied

Scientific EffectReflection: Reflection

Implementation Method 2

an optical member that has a plate shape, is provided between the display panel and the light source substrate, and uniformizes luminance distribution of the light emitted from the light source substrate

Methodology Applied

Scientific EffectLight diffusion: Diffusion

Data Source

PatentEP3346324B1Video display device

Publication Date: 2020.06.03 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

Figure 1
Figure 2
Figure 3

AI summary

Provided is a video display device capable of reducing luminance lowering or luminance non-uniformity caused at an end of an effective area of a display panel. A video display device includes: a display panel that displays an image based on an input image signal; a light source substrate that includes a plurality of light sources on a main surface which is a front side of the light source substrate, and emits, toward a rear side of the display panel, light emitted from the plurality of light sources; a reflection sheet that is provided on the main surface of the light source substrate, and in which hollow partitioning walls each of which separates adjacent two light sources of the plurality of light sources are formed; and an optical member that has a plate shape, is provided between the display panel and the light source substrate, and uniformizes luminance distribution of the light emitted from the light source substrate. The reflection sheet extends to an outside of an outer peripheral edge of the optical member as viewed from the front side.