Light Guide Plate Protrusion Angles for Luminosity Consistency
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Solution Overview
Problem
Conventional light emitting devices for liquid crystal display backlights face challenges in maintaining consistent luminosity across different observation angles, requiring a wider light emission angle to suppress luminosity changes.
Innovation Solution
A light emitting device design featuring a light guide plate with specific protrusion parts and a prism sheet, where the light guide plate has triangular prism-shaped protrusions on its surfaces with optimized apex and base angles, allowing for collimated light emission by adjusting the emission angles of light beams to be parallel to a specific direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional light emitting devices are used for liquid crystal display backlights, then the device structure is simple, but the luminosity changes significantly with observation angle
Solution Approach 1:
The light guide plate is segmented with multiple protrusion parts having different apex angles arranged in specific patterns. These segmented regions redirect light at different angles to achieve uniform luminosity distribution across various observation angles, resolving the contradiction between luminosity consistency and structural simplicity.
Solution Approach 2:
Different regions of the light guide plate are given different local optical properties through protrusion parts with varying apex angles (e.g., 60°, 90°, 120°). Each local region optimizes light redirection for specific angular ranges, achieving overall luminosity consistency without requiring complete structural redesign.
2Illumination intensity
If the light emission angle is increased to suppress luminosity changes, then the luminosity consistency improves, but the light extraction efficiency decreases
Solution Approach 1:
The apex angles of protrusion parts are precisely controlled within specific ranges (e.g., 55°-65° for first protrusion parts, 1°-3° for second protrusion parts). By optimizing these geometric parameters, the device achieves both wide light emission angles for luminosity consistency and efficient light extraction, resolving the energy loss contradiction.
Solution Approach 2:
The light redirection mechanism dynamically adapts to different incident angles through the geometric configuration of protrusion parts. Light rays at different angles encounter appropriately angled protrusions that redirect them toward the desired emission direction, maintaining both wide angular coverage and extraction efficiency.
3Illumination intensity
If protrusion parts with optimized apex angles are introduced to control light direction, then the light emission angle and luminosity consistency improve, but the manufacturing complexity increases
Solution Approach 1:
The light guide plate is segmented with multiple protrusion parts having different apex angles arranged in specific patterns. These segmented regions redirect light at different angles to achieve uniform luminosity distribution across various observation angles, resolving the contradiction between luminosity consistency and structural simplicity.
Solution Approach 2:
Different regions of the light guide plate are given different local optical properties through protrusion parts with varying apex angles (e.g., 60°, 90°, 120°). Each local region optimizes light redirection for specific angular ranges, achieving overall luminosity consistency without requiring complete structural redesign.
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 device achieves even light emission across angles, reducing noise and improving light extraction efficiency, enabling controlled light directionality and maintaining luminosity consistency.
Implementation Method 1
a light guide plate with a first main surface on which a plurality of first protrusion parts arranged along a first direction and extending along a second direction which crosses the first direction... allowing for collimated light emission by adjusting the emission angles of light beams to be parallel to a specific direction
Implementation Method 2
a prism sheet disposed to be opposed to the first main surface... achieving even light emission across angles, reducing noise and improving light extraction efficiency
Data Source
AI summary
According to one embodiment, a light emitting device includes a light guide plate with a plurality of first protrusion parts arranged along a first direction and extending along a second direction which crosses the first direction, and a prism sheet, wherein a cross-sectional shape of each of the first protrusion parts along the first direction has an apex angle between 55 degrees and 65 degrees, inclusive, the light guide plate includes a plurality of second protrusion parts which extend along the first direction and are arranged along the second direction, and a cross-sectional shape of each of the second protrusion parts along the second direction has a base angle between 1 degree and 3 degrees, inclusive.