Optical Apparatus Light-Shielding Resin for Proximity Sensor Noise Reduction
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Solution Overview
Problem
Proximity sensors in electronic devices often experience false detection due to noise light from large incident angles and transparent resins, leading to incorrect object proximity determination.
Innovation Solution
An optical apparatus with a substrate, light-receiving and light-emitting elements, and light-transmitting and light-shielding resins, where the light-shielding resin includes a first opening with an irregular surface and a bonding portion, and light-blocking portions to prevent noise light from reaching the light-receiving element, reducing false detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the proximity sensor is arranged at a certain distance from the light-transmitting cover, then the sensor can detect objects, but noise light with large incident angles is reflected by the cover and causes false detection
Solution Approach 1:
A light-shielding resin is introduced as an intermediary component between the light-transmitting cover and the light-receiving element. This resin contains light-absorbing particles that intercept and absorb noise light reflected from the light-transmitting cover, preventing it from reaching the light-receiving element and causing false detection, thereby resolving the contradiction between detection capability and noise resistance
Solution Approach 2:
The harmful noise light is extracted and removed from the optical path by the light-shielding resin. The resin selectively absorbs the reflected noise light with large incident angles while allowing the useful infrared light from the light-emitting element to pass through to the light-receiving element, thus eliminating the false detection problem
2Ease of manufacture
If the light-shielding resin directly contacts the substrate, then manufacturing is simplified, but condensation may occur between the resin and substrate
Solution Approach 1:
The light-shielding resin is segmented into two distinct portions: a first portion that contacts the substrate and a second portion that covers the light-transmitting resin. This segmentation allows the first portion to serve as an adhesive layer for simplified manufacturing while the second portion provides the light-shielding function, and the interface between portions prevents condensation accumulation
Solution Approach 2:
The light-shielding resin extends in the vertical dimension with different portions at different heights. The first portion lies flat on the substrate surface while the second portion rises to cover the light-transmitting resin, creating a stepped structure that eliminates condensation traps while maintaining manufacturing simplicity
3Strength
If transparent resin is used to cover the light-receiving element, then the element is protected, but light emitted from the light-emitting element may pass through and cause false detection
Solution Approach 1:
The resin material is given different local qualities: the light-transmitting resin covering the light-emitting element is transparent to allow light emission, while the light-shielding resin covering the light-receiving element contains light-absorbing particles to block stray light. This local differentiation of material properties protects the light-receiving element while preventing false detection
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 effectively reduces false detection by blocking noise light and ensuring accurate object proximity determination, enhancing the reliability of proximity sensors in electronic devices.
Implementation Method 1
a light-shielding resin covering the first light-transmitting resin and the second light-transmitting resin... The wiring pattern includes a first light-blocking portion interposed between the light-shielding resin and the substrate
Implementation Method 2
The light-emitting element 92 emits infrared light
Implementation Method 3
The light-receiving element 93 sends out an electric signal corresponding to the amount of received infrared light
Implementation Method 4
The primary mold resin portions 94 and 95 are transparent and transmit infrared light
Implementation Method 5
The infrared light L91 impinging on the light-transmitting cover 903 with a relatively large incident angle is reflected by the light-transmitting cover 903 to become noise light L92
Data Source
AI summary
An optical apparatus includes a substrate 1, a wiring pattern 8 formed on the substrate 1, a light-receiving element 3 and a light-emitting element 2 provided on the substrate 1 and spaced apart from each other in a direction x, a light-transmitting resin 4 covering the light-receiving element 3, a light-transmitting resin 5 covering the light-emitting element 2, and a light-shielding resin 6 covering the light-transmitting resin 4 and the light-transmitting resin 5. The wiring pattern 8 includes a first light-blocking portion 83 interposed between the light-shielding resin 6 and the substrate 1 and positioned between the light-receiving element 3 and the light-emitting element 2 as viewed in x-y plane. The first light-blocking portion 83 extends across the light-emitting element 2 as viewed in the direction x.