VCSEL Substrate Spacing via Mediator Joint
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Solution Overview
Problem
In the manufacturing of on-vehicle ignition systems using vertical cavity-surface emitting laser (VCSEL) devices, the precise alignment and spacing of substrates are challenging due to uneven adhesive distribution, leading to optical property deterioration and difficulty in controlling the angle of radiation of laser beams.
Innovation Solution
The use of spacers with specific shapes, such as rectangular, chamfered, curved, or stepped configurations, to stabilize the adhesive and maintain precise positioning between the VCSEL array substrate and the microlens array substrate, ensuring consistent adhesive spread and minimizing interference with the light-emitting and lens units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If substrates are bonded using adhesive in a direct manner, then the manufacturing process is simple, but the adhesive distribution becomes uneven leading to deterioration of optical properties
Solution Approach 1:
A joint structure is introduced as an intermediary component between the first substrate and second substrate. The joint includes a first part contacting the first substrate and a second part extending toward the light-emitting unit, with the second part having a smaller cross-sectional area. This intermediary structure mediates the adhesive bonding process, guiding adhesive distribution along the joint structure to prevent uneven spread and contact with optical elements.
2Strength
If adhesive is applied to bond substrates, then the substrates are fixed together, but the adhesive interferes with light-emitting units and lens units deteriorating optical properties
Solution Approach 1:
The joint structure serves as a mediator that directs adhesive flow and containment. The adhesive is applied to bond the joint structure to the substrates, and the joint's geometry (with the second part having smaller cross-sectional area extending toward the light-emitting unit) prevents adhesive from reaching and interfering with optical elements while maintaining bonding strength.
Solution Approach 2:
The joint structure has different cross-sectional areas at different locations: a larger first part for stable substrate contact and a smaller second part near the light-emitting unit. This local variation in geometry allows the joint to provide adequate bonding area while preventing adhesive overflow into sensitive optical regions.
3Adaptability or versatility
If the spacing between substrates is not precisely controlled, then the device structure is flexible, but the angle of radiation of laser beams cannot be controlled
Solution Approach 1:
The joint structure acts as a spacing mediator between substrates. By controlling the dimensions and geometry of the joint (particularly the height and cross-sectional area of its parts), the spacing between the first substrate and second substrate is precisely determined, which in turn controls the angle of radiation of laser beams from the VCSEL devices.
Data Source
AI summary
An optical device and a light-source device. The optical device includes a first substrate having a first plane and elements, and a second substrate having a second face that faces the first plane. The elements are disposed on the first substrate to emit or receive light in a direction intersecting with the first plane. The second substrate includes lenses disposed to correspond to the elements, and the second substrate extends in a first direction parallel to the second face to contact the first plane. The second substrate has a joint used to determine spacing between the first substrate and the second substrate, and the joint contacts the first substrate with an area smaller than a maximum size of cross-sectional area parallel to the second face of the joint. The light-source device includes the optical device and a driver to drive the optical device.