Optical Module Encoder Resin Anti-Reflective Layer
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Solution Overview
Problem
The reflection-type encoder requires simplification of configuration and improvement of detection accuracy.
Innovation Solution
An optical module for an encoder is introduced, featuring a support with a bottom wall and side walls, a light receiving element and a light emitting element on the bottom wall, a light transmitting member on the side wall, and a resin member with a lower refractive index than the light transmitting member, functioning as an anti-reflective layer to suppress noise light and improve detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a separate bonding member is used to attach the light transmitting member to the side wall part, then the bonding function is achieved, but the configuration becomes more complex and the light transmission area is reduced
Solution Approach 1:
The resin member integrates two functions: it serves as both the bonding material to attach the light transmitting member to the side wall part, and as an anti-reflective layer to suppress noise light. This merging of functions eliminates the need for a separate bonding member, simplifying the configuration while maintaining reliable bonding and light transmission.
2Object-affected harmful factors
If the light transmitting member is disposed on the side wall part with an anti-reflective layer and bonding member, then noise light is suppressed, but the distance from the light elements to the rotary plate increases causing light spreading
Solution Approach 1:
The resin member combines the anti-reflective layer function with the bonding function into a single integrated component. This integration allows the light transmitting member to be positioned closer to the light emitting element and rotary plate, reducing the distance and minimizing light spreading, thereby improving detection accuracy while still suppressing noise light.
3Reliability
If a resin adhesive is used for bonding, then the bonding function is achieved, but the adhesive protrudes into the side wall part and blocks the light transmitting member surface
Solution Approach 1:
The resin member serves as both the bonding material and the anti-reflective layer, with its surface forming a smooth interface that does not protrude into the light transmission path. This integrated design ensures complete bonding functionality while maintaining the full light transmission area of the light transmitting member surface.
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 optical module simplifies the configuration by eliminating the need for a separate bonding member and improves detection accuracy by reducing noise light and increasing the amount of light received by the light receiving element.
Implementation Method 1
a refractive index of the resin member with respect to light having a center wavelength of light emitted from the light emitting element is smaller than a refractive index of the light transmitting member with respect to the light having the center wavelength, and the light transmitting member is bonded to the side wall part by a portion of the resin member formed on the outer region
Data Source
AI summary
An optical module includes: a support having a bottom wall part and a side wall part; a light receiving element and a light emitting element; a light transmitting member disposed on the side wall part; and a resin member disposed on a surface of the light transmitting member. The surface of the light transmitting member has an inner region and an outer region. The resin member is integrally formed over the inner region and the outer region. A refractive index of the resin member with respect to light having a center wavelength of light emitted from the light emitting element is smaller than a refractive index of the light transmitting member with respect to the light having the center wavelength. The light transmitting member is bonded to the side wall part by a portion of the resin member formed on the outer region.