LED Array Lighting Device Uniform Illumination
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Solution Overview
Problem
Conventional lighting devices using halogen lamps for downlights are inefficient in energy use and require large reflectors, while LED lamps struggle with luminous efficiency due to high drive currents and uneven illuminance.
Innovation Solution
A lighting device with a high-density array of LED chips on a substrate, forming a planar light source with reduced drive current per chip, which enhances energy efficiency and uniform luminance, allowing for a smaller form factor and reduced heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a halogen lamp is used as a light source, then the lighting device can emit light in various directions, but the energy efficiency deteriorates due to large heat generation
Solution Approach 1:
The invention divides the single-point halogen lamp light source into multiple LED chips arranged in an array. Each LED chip emits light in a specific direction, and collectively they provide comprehensive illumination. This segmentation eliminates the need for large reflectors and significantly improves energy efficiency while maintaining light emission capability.
2Ease of operation
If a cone-shaped reflector is used to direct light from a halogen lamp, then the light can be directed toward a desired range, but the device complexity and space requirement increase
Solution Approach 1:
The invention extracts and eliminates the cone-shaped reflector component by using an array of LED chips that inherently emit light in the desired direction. Each LED chip is positioned and oriented to provide direct illumination without requiring additional reflective surfaces, thereby simplifying the device structure and reducing space requirements.
3Illumination intensity
If the drive current to LED modules is increased to increase luminance, then the brightness improves, but heat generation increases and luminous efficiency deteriorates
Solution Approach 1:
Instead of increasing the drive current to a few LED modules, the invention segments the light source into numerous LED chips arranged in an array. This allows the total luminance to be achieved by combining the output of many chips operating at lower, more efficient current levels, thereby maintaining brightness while improving luminous efficiency and reducing heat generation per chip.
4Shape
If a case with strong diffusion effect is used to make LED modules look like a fluorescent lamp, then the appearance is improved, but the transmittance decreases and luminous efficiency deteriorates
Solution Approach 1:
The invention uses a dense array of LED chips that collectively create a uniform planar light source appearance without requiring strong diffusion. The high density of chips (mounting density of not less than 3/cm²) ensures uniform light emission across the surface, eliminating the need for diffusive cases and preserving high transmittance and luminous efficiency.
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 achieves improved energy efficiency, reduced heat generation, and uniform surface luminescence, enabling a more compact design and higher luminous efficiency compared to traditional halogen-based systems.
Implementation Method 1
a lighting device which includes a substrate and a planar light source portion including a plurality of LED chips arrayed on the substrate
Implementation Method 2
a reflector which surrounds the planar light source portion and has a function of reflecting light from the planar light source portion in a forward direction
Data Source
AI summary
A lighting device includes a substrate having a side extending straight in a first direction and a first LED chip supported by the substrate and having a first anode terminal and a first cathode terminal. The lighting device includes a second LED chip and a third LED chip supported by the substrate, being electrically connected to the second cathode terminal, and being overlapped with the first LED chip when viewed in a second direction that is perpendicular to the first direction. The lighting device includes a connecting portion that connects the first cathode terminal and the second anode terminal with each other, at least a portion of the connecting portion angled at an acute angle with respect to the second direction.