Vehicle Lamp Optical Element Surface Roughness Tackiness
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Solution Overview
Problem
Vehicle lighting devices with light-emitting diodes face issues with tackiness in light-transmitting resin lenses, leading to potential deviations in mounting position, which can affect light distribution characteristics and cause lenses to adhere to each other or accommodation members, hindering efficient manufacturing and integration.
Innovation Solution
The use of a light-transmitting resin with an arithmetic-average roughness of 0.3 to 2.0 µm on the outer surface of optical elements, combined with fine concave portions on the surface, reduces tackiness and enhances joining strength while minimizing impact on optical characteristics, allowing for stable mounting and efficient handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a light-transmitting resin lens is used, then manufacturing cost is reduced, but tackiness causes mounting position deviation and adhesion issues
Solution Approach 1:
The patent changes the surface roughness parameter of the lens from smooth to a specific rough range (arithmetic-average roughness of 0.3 to 2.0 µm). This parameter change reduces the tackiness of the light-transmitting resin while maintaining adequate joining strength, thereby preventing mounting position deviation and adhesion problems during handling and integration.
Solution Approach 2:
The patent applies local quality by creating fine concave portions only on the outer surface of the lens that contacts the sealing portion, while maintaining optical quality in other regions. This localized surface modification addresses the tackiness issue at the contact interface without compromising the overall optical performance of the lens.
2Strength
If lens tackiness is strong, then joining strength may be adequate, but detachment from vacuum chuck is hindered and mounting position deviates
Solution Approach 1:
The patent optimizes the surface roughness parameter to a specific range (0.3 to 2.0 µm arithmetic-average roughness) that balances joining strength and handling ease. This parameter change reduces excessive tackiness that hinders detachment from vacuum chucks while maintaining sufficient joining strength for secure mounting.
Solution Approach 2:
The patent applies partial action by creating only fine concave portions on the specific outer surface area that contacts the sealing portion, rather than modifying the entire lens surface. This localized approach reduces tackiness where needed for handling while maintaining adequate bonding capability at the contact interface.
3Strength
If lens tackiness is strong, then joining strength may be adequate, but lenses adhere to each other and accommodation members
Solution Approach 1:
The patent changes the surface roughness parameter to reduce tackiness, preventing lenses from adhering to each other and to accommodation members during integration. This parameter change maintains adequate joining strength for proper mounting while eliminating excessive adhesion that hinders efficient handling and assembly.
Solution Approach 2:
The patent applies local quality by modifying only the outer surface area that contacts the sealing portion with fine concave portions. This localized surface modification reduces tackiness at the contact interface, preventing unwanted adhesion during handling and integration while maintaining sufficient joining strength for secure mounting.
4Ease of operation
If surface roughness is increased to reduce tackiness, then handling improves, but optical characteristics may be affected
Solution Approach 1:
The patent precisely controls the surface roughness parameter within a specific range (arithmetic-average roughness of 0.3 to 2.0 µm) that reduces tackiness for improved handling while maintaining adequate optical characteristics. This controlled parameter change balances handling ease with optical performance.
Solution Approach 2:
The patent applies local quality by creating fine concave portions only on the outer surface area that contacts the sealing portion. This localized modification reduces tackiness at the contact interface without significantly affecting the overall optical characteristics of the lens, as the modified area is limited to the periphery.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A vehicle lighting device (1) according to an embodiment includes: a socket (10); a substrate (21) that is provided on one end portion side of the socket (10); a frame portion (25) that is provided on the substrate (21; at least one light-emitting element (22) that is provided in a region on an inner side of the frame portion (25) on the substrate (21); a sealing portion (26) that is provided on an inner side of the frame portion (25) and covers the light-emitting element (22); and an optical element (27) that is provided on the sealing portion (26). An arithmetic-average roughness value of a first surface (27b1, 27a2) on the sealing portion side (26) in the optical element is greater than an arithmetic-average roughness value of a second surface (27a1) of the optical element (27) on a side opposite to the first surface (27b1, 27a2).