Integrated Proximity Sensor with Ambient Light Recess
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Solution Overview
Problem
The existing proximity sensors in electronic devices face issues with ambient light interference, leading to incorrect determinations and malfunctions, requiring separate semiconductor packages for light transmitters, receivers, and ambient light sensors, which occupy significant space and increase costs.
Innovation Solution
A semiconductor package design that integrates a light transmitter, a light receiver, and an ambient light sensor within a single package using a cap with a recess, allowing the ambient light sensor to be mounted alongside the light transmitter and receiver, reducing the need for additional packages and minimizing space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate semiconductor packages are used for light transmitter, light receiver, and ambient light sensor, then measurement precision is improved, but device complexity and space occupation increase
Solution Approach 1:
The patent combines the light transmitter, light receiver, and ambient light sensor into a single integrated semiconductor package. The light transmitter and light receiver are positioned in close proximity on the same substrate, with the ambient light sensor integrated alongside them. This merging eliminates the need for separate packages while maintaining the functional independence of each component, thereby reducing overall device complexity and space occupation while preserving measurement precision through proper optical isolation and signal processing.
2Reliability
If separate semiconductor packages are used for light transmitter, light receiver, and ambient light sensor, then reliability is improved, but area of stationary object increases
Solution Approach 1:
The patent implements a nested arrangement where the ambient light sensor is positioned within the same package footprint as the light transmitter and light receiver. The components are arranged in a compact configuration on a single substrate, with the ambient light sensor effectively nested within the overall package structure. This nesting approach maintains reliable detection by ensuring proper optical paths and isolation while minimizing the total area occupied by the sensor assembly.
3Area of stationary object
If ambient light sensor is integrated into the same package, then area of stationary object is reduced, but object-generated harmful factors increase
Solution Approach 1:
The patent extracts the ambient light measurement function from the proximity detection path by positioning the ambient light sensor to measure only ambient light levels without receiving the modulated light from the light transmitter. The sensor is oriented and positioned such that it measures ambient light separately, allowing the system to subtract this background level from the light receiver's measurements. This extraction approach eliminates ambient light interference as a harmful factor while maintaining compact integration.
Solution Approach 2:
The integrated ambient light sensor provides continuous feedback on ambient light levels to the control system. This feedback enables real-time compensation by adjusting the proximity detection threshold based on current ambient conditions. The system uses this feedback to distinguish between ambient light variations and actual proximity events, thereby eliminating false detections while maintaining the compact integrated package structure.
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 integrated design prevents incorrect determinations due to ambient light, maintains compactness, and reduces manufacturing costs by eliminating the need for separate ambient light sensor packages, while ensuring accurate proximity detection and adaptive screen brightness.
Implementation Method 1
The light transmitter emits pulses of light at a frequency to detect when a body part or face of the user comes near a cellphone. The light transmitter will emit a pulse of light at a certain frequency which will be reflected by a user's face or body part when the user comes close to the proximity sensor. The reflected transmitted light is then received by the light receiver.
Implementation Method 2
it is desired to have an ambient light sensor to make sure that the ambient light is taken into account while the light receiver is taking readings
Data Source
AI summary
A semiconductor package that is a proximity sensor includes a light transmitting die, a light receiving die, an ambient light sensor, a cap, and a substrate. The light receiving die and the light transmitting die are coupled to the substrate. The cap is coupled to the substrate forming a first chamber around the light transmitting die and a second chamber around the light receiving die. The cap further includes a recess with contact pads. The ambient light sensor is mounted within the recess of the cap and coupled to the contact pads. The cap includes electrical traces that are coupled to the contact pads within the recess coupling the ambient light sensor to the substrate. By utilizing a cap with a recess containing contact pads, a proximity sensor can be formed in a single semiconductor package all while maintaining a compact size and reducing the manufacturing costs of proximity sensors.