Light Guide Plate Prism Orientation for Uniform Brightness
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Solution Overview
Problem
The illumination device using a light guide plate with multiple optical path changing elements results in varying light intensity distribution when viewed from different directions, which is undesirable for applications requiring consistent brightness.
Innovation Solution
A light guide plate with prisms arranged in a predetermined pattern, where reflection surfaces of prisms separated by a specific pitch are oriented in the same direction, and those closer than the pitch are oriented in different directions within a plane parallel to the surface, reducing brightness variations when viewed from different angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple optical path changing elements are arranged on the light guide plate to broaden illumination area, then the illumination area is increased, but the brightness distribution becomes uneven when viewed from different directions
Solution Approach 1:
The light guide plate is divided into multiple regions with different prism orientations. Specifically, the plate is segmented into a first region with prisms oriented in a first direction and a second region with prisms oriented in a second direction different from the first. This segmentation allows different portions of the illumination area to be optimized for different viewing directions, thereby broadening the overall illumination area while maintaining relatively uniform brightness distribution across various viewing angles.
2Ease of operation
If optical path changing elements are arranged to provide directional light reflection, then light directivity is improved, but brightness varies significantly when viewed from different directions
Solution Approach 1:
The patent employs asymmetric arrangement of prisms with different orientations in different regions of the light guide plate. Rather than using uniform symmetric orientation throughout, the prism orientations are deliberately made asymmetric across regions, creating complementary light reflection patterns that maintain good light directivity in each region while achieving overall brightness consistency when viewed from multiple directions.
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 arrangement minimizes brightness differences when viewing an illuminated pattern from various directions, presenting a more uniform brightness to the observer.
Implementation Method 1
a plurality of prisms arranged along one surface of the light guide plate and distributed in a predetermined pattern, the prisms including a reflection surface that reflects the visible light emitted from the light source and entering the light guide plate from the input surface toward another surface of the light guide plate
Data Source
AI summary
A light guide plate, produced from material transparent to visible light, includes a plurality of prisms provided on one surface (a diffusion surface) thereof in a predetermined pattern. The plurality of prisms include a reflection surface that reflects visible light emitted from a light source and entering the light guide plate from an input surface toward another surface (an output surface). Each prism in the plurality of prisms is distributed so that the reflection surfaces of two prisms separated by a predetermined pitch are oriented in the same direction, and the reflections surfaces of two prisms that are closer than the predetermined pitch are oriented in mutually different directions.