Light Emitting Device Lens with Reflecting Face for Uniform Luminance
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Solution Overview
Problem
Existing light emitting devices used in image display apparatuses, such as television receivers, face challenges in maintaining uniform luminance due to the design of lenses that can lead to uneven light distribution, particularly when the thickness of the device is reduced, causing part of the light to pass through the bottom face and be reflected at various angles, resulting in luminance unevenness.
Innovation Solution
A light emitting device with a lens featuring a light path controlling projecting portion on its outer circumference, which includes a reflecting face that redirects inwardly reflected light to a predetermined direction, ensuring that light is either entirely or substantially entirely reflected and emitted laterally, thereby maintaining uniform luminance across the display panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the thickness of the light emitting device is reduced, then the device becomes more compact and modern, but the luminance uniformity deteriorates due to light passing through the bottom face at various angles
Solution Approach 1:
The lens is divided into two functional regions: a central light emitting region and a peripheral light path controlling projecting portion. This segmentation allows different parts of the lens to perform different functions - the central region emits light forward while the peripheral region redirects lateral light, thereby maintaining luminance uniformity even when the device thickness is reduced.
Solution Approach 2:
The invention addresses the thickness reduction problem by adding a lateral light control dimension. The light path controlling projecting portion extends in the lateral direction (perpendicular to the optical axis) to intercept and redirect light that would otherwise pass through the bottom face, effectively compensating for the reduced thickness without compromising luminance uniformity.
2Ease of manufacture
If a flat bottom face is used in the lens, then the manufacturing is simpler, but luminance unevenness occurs due to light passing through at various angles after reflection
Solution Approach 1:
The lens is divided into two functional regions: a central light emitting region and a peripheral light path controlling projecting portion. This segmentation allows different parts of the lens to perform different functions - the central region emits light forward while the peripheral region redirects lateral light, thereby maintaining luminance uniformity even when the device thickness is reduced.
Solution Approach 2:
The invention addresses the thickness reduction problem by adding a lateral light control dimension. The light path controlling projecting portion extends in the lateral direction (perpendicular to the optical axis) to intercept and redirect light that would otherwise pass through the bottom face, effectively compensating for the reduced thickness without compromising luminance uniformity.
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 increases the lateral emission of light from the light emitting diode, ensuring uniform luminance distribution on the display panel, preventing luminance unevenness and enhancing the overall performance of the light emitting device, area light source apparatus, and image display apparatus.
Implementation Method 1
the light path controlling projecting portion has formed thereon a reflecting face for reflecting the light reflected inwardly by the lens inwardly again
Data Source
AI summary
Disclosed herein is a light emitting device, including: a light emitting diode; an sealing resin member having an arrangement face and configured to seal the light emitting diode; and a lens disposed on the arrangement face of the sealing resin member and formed so as to have a circular shape as viewed in the direction of an optical axis of light emitted from the light emitting diode, the lens having a concave portion formed at a central portion in such a manner as to be concave toward the sealing resin member.