Crescent Moon Phosphor for Light Distribution Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light emitting device packages face challenges in controlling light distribution, leading to mura and yellow ring phenomena due to the dispersion of fluorescent materials, and require separate phosphor sheets for each device, limiting manufacturing versatility.
Innovation Solution
A light emitting device package design featuring a substrate with a reflecting member and a transparent encapsulant containing a concave phosphor accommodating space, where the phosphor is shaped to have a crescent moon cross-section, optimizing light distribution and preventing peeling phenomena without the need for a separate phosphor sheet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a phosphor is formed by dispensing a fluorescent material mixed with an epoxy inside a reflector cup, then the light distribution curve width is increased, but it becomes difficult to control light and causes mura and yellow ring phenomena
Solution Approach 1:
The phosphor layer is designed with non-uniform thickness, being thicker at the center and thinner at the edges, to create different optical properties in different regions. This local variation in phosphor thickness compensates for the natural spreading of light, maintaining a controlled light distribution curve width while preventing mura and yellow ring phenomena.
Solution Approach 2:
The invention transitions from controlling light distribution in two dimensions (horizontal spread) to controlling it through the third dimension (vertical thickness variation). By varying the phosphor thickness in the vertical dimension, the patent achieves precise control over the light distribution curve width without increasing it excessively.
2Ease of manufacture
If a phosphor shaped like a sheet and the same thickness is attached to the light emitting device, then the manufacturing process is simplified, but a peeling phenomenon is generated at the boundary surface
Solution Approach 1:
The phosphor layer transitions from uniform thickness to non-uniform thickness, being thicker at the center and thinner at the edges. This design ensures that the phosphor naturally tapers toward the boundary surfaces, eliminating air gaps and foreign substances that cause peeling, while maintaining firm attachment across the entire surface.
Solution Approach 2:
Instead of attaching a phosphor sheet of uniform thickness that creates peeling at the edges, the invention inverts the approach by using a phosphor layer that is inherently thinner at the edges. This inversion of the thickness profile prevents the peeling phenomenon that occurs with uniform thickness sheets.
3Reliability
If separate phosphor sheets for each light emitting device are ordered and manufactured in advance, then the peeling phenomenon is prevented, but the production line versatility is limited
Solution Approach 1:
The invention merges the phosphor application process with the standard LED packaging process. The phosphor is applied directly to the LED chip during the normal manufacturing sequence using existing equipment, eliminating the need for separate phosphor sheet manufacturing and attachment steps. This integration maintains reliable phosphor attachment while enabling the production line to handle various LED standards.
Solution Approach 2:
The phosphor application method is designed to be universal, working with different LED chip sizes and configurations without requiring dedicated phosphor sheets for each standard. The direct application process using existing packaging equipment provides multi-functionality across various production lines.
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 design enhances light control, prevents mura and yellow ring phenomena, ensures phosphor fixation, and allows for versatile application across various standards without requiring a separate phosphor sheet, improving manufacturing efficiency and durability.
Implementation Method 1
a transparent encapsulant charged in the reflector cup of the reflecting member in a flow state and hardened
Implementation Method 2
a phosphor charged in the phosphor accommodating space in a flow state and hardened
Implementation Method 3
The phosphor may have a crescent moon shape in which a cross section at a center portion is thick and a cross section at a boundary portion is thin, and have a larger length than a width of the light emitting device
Data Source
AI summary
Disclosed are a light emitting device package, a backlight unit, and a lighting device which are usable for a display or lighting, and a method of manufacturing the light emitting device package. The light emitting device package includes: a substrate; a light emitting device seated on the substrate; a reflecting member provided on the substrate and provided with a reflector cup surrounding a lateral circumference of the light emitting device; a transparent encapsulant charged in the reflector cup of the reflecting member in a flow state and hardened, and provided with a concave phosphor accommodating space in an upper surface thereof; and a phosphor charged in the phosphor accommodating space in a flow state and hardened.