Light Guiding Unit with Shielding for Display Illumination

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Solution Overview

Problem

The existing display apparatuses, such as those disclosed in JP-A-2007-127909, face challenges in achieving a desired display due to light diffusion from the light source, leading to suboptimal illumination and visibility issues.

Innovation Solution

A display apparatus is designed with a light guiding unit having an incident surface, an emitting surface, and an intermediate surface, along with a light shielding unit featuring sloping surfaces and a diffusing sheet to control light emission and minimize light leakage, ensuring focused illumination and improved visibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a light guiding unit is used to guide light from LEDs, then light can be directed to the display surface, but light diffusion occurs causing undesired display quality

Engineering Contradiction:
Improvelight directionalityVSAvoiddisplay quality
Core Design Contradiction:
Illumination intensityVSManufacturing precision

Solution Approach 1:

The light guiding unit is divided into multiple light guiding portions, each corresponding to individual LEDs. This segmentation allows precise control of light paths from each LED to specific regions of the display surface, preventing light diffusion and improving display quality.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the light guiding unit have different optical properties tailored to their specific functions. The light guiding portions have refractive indices and geometries optimized for directing light from specific LEDs to specific display regions, achieving local optimization of light control.

Inventive Principle:
Principle #3Local quality

2Illumination intensity

If light is emitted from multiple LEDs to cover the display area, then sufficient illumination is achieved, but light leakage occurs from intermediate surfaces

Engineering Contradiction:
Improvedisplay illuminationVSAvoidlight leakage
Core Design Contradiction:
Illumination intensityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes light leakage from intermediate surfaces by designing the light guiding unit to confine light primarily to the light guiding portions. The light shielding unit further extracts and blocks any straying light from reaching intermediate surfaces, eliminating the harmful light leakage effect.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the potential harmful light leakage into beneficial illumination by designing the light guiding portions to direct light precisely to the display surface. Any light that might have leaked is instead channeled through the light shielding unit to illuminate specific display regions, turning a potential defect into a functional advantage.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively prevents unnecessary light leakage, providing a clear and uniform illumination in the display area, enhancing the visibility and design of the electronic keyboard instrument by directing light efficiently from the LEDs to the intended emission surface.

Implementation Method 1

a light guiding unit configured to have an incident surface on which light from the at least one light source is incident, an emitting surface from which light from the at least one light source is emitted

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

along with a light shielding unit featuring sloping surfaces and a diffusing sheet to control light emission

Methodology Applied
Scientific EffectLight scattering: Scattering

Data Source

PatentEP4485434A1Display apparatus and electronic instrument
Publication Date: 2025.01.01 CASIO COMPUTER CO LTD
  • EP4485434A1 patent drawingFigure 1
  • EP4485434A1 patent drawingFigure 2
  • EP4485434A1 patent drawingFigure 3

AI summary

A display apparatus (40) comprises at least one light source (72), a light guiding unit (60) configured to have an incident surface (64b1) on which light from the at least one light source (72) is incident, an emitting surface (64a1) from which light from the at least one light source (72) is emitted, and at least one intermediate surface (64c, 64d) positioned between the incident surface (64b1) and the emitting surface (64a1), and a light shielding unit (50) configured to have an inner wall surface (58a3, 58a4) facing a side of at least a part of the at least one intermediate surface (64c, 64d) and at least one continuous surface (50C1, 50C2) facing a side of the emitting surface (64a1) and continuing from the inner wall surface (58a3, 58a4) in a direction in which the at least one continuous surface (50C1, 50C2) extends away from the at least one intermediate surface (64c, 64d).