Integrated ToF Sensor Layout With Opaque Wall Optical Isolation
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Solution Overview
Problem
Conventional time-of-flight (ToF) sensors are bulky, require separate housings for light sources and image sensors, and consume high power, limiting their integration and miniaturization.
Innovation Solution
The development of back-side-illuminated (BSI) and front-side-illuminated (FSI) ToF sensors using hybrid bonding of two semiconductor dies, where an opaque wall blocks direct light paths, allowing only reflected light to reach the image sensor, and incorporating a light-emitting diode (LED) and image sensor on a single substrate with reduced surface area and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ToF sensors use separate housings for light sources and image sensors, then the sensor can achieve proper optical isolation, but the device becomes bulky and complex
Solution Approach 1:
The patent merges the light source and image sensor onto a single semiconductor substrate, eliminating the need for separate housings. The LED is positioned in a first region and the image sensor in a second region of the same substrate, achieving optical isolation through careful layout and opaque wall structures rather than separate mechanical housings.
Solution Approach 2:
The patent introduces opaque walls as intermediary structures between the LED and the image sensor. These opaque walls block direct light paths while allowing the components to coexist on the same substrate, providing the necessary optical isolation without requiring separate housings.
2Reliability
If conventional ToF sensors use separate housings for light sources and image sensors, then optical isolation is achieved, but the sensor size increases
Solution Approach 1:
By combining the LED and image sensor on a single substrate, the patent eliminates the volume required for separate housings. The integrated layout allows the light source and detector to occupy minimal space on the substrate while maintaining optical isolation through opaque walls and strategic positioning.
Solution Approach 2:
The patent utilizes the vertical dimension by forming opaque walls that extend through multiple layers of the semiconductor structure. This three-dimensional arrangement allows optical isolation without increasing the planar footprint, effectively using the z-dimension to block light paths while maintaining a compact top view.
3Reliability
If conventional ToF sensors use separate housings, then optical isolation is ensured, but power consumption increases
Solution Approach 1:
The integrated design on a single substrate reduces the overall power consumption by eliminating the need for separate housing structures and reducing the total area requiring illumination. The closer proximity of the LED and image sensor allows for more efficient light utilization and reduced power requirements for optical isolation.
4Volume of moving object
If the LED and image sensor are placed close together on the same substrate, then the sensor is miniaturized, but direct light paths may reach the image sensor
Solution Approach 1:
The patent introduces opaque walls as intermediary structures positioned between the LED and the image sensor. These opaque walls act as mediators that block direct light paths while allowing the components to be positioned close together on the same substrate, enabling miniaturization without compromising optical isolation.
Solution Approach 2:
The patent extracts and removes the harmful direct light paths by introducing opaque barrier walls. These walls are strategically positioned to intercept and block direct light from the LED before it can reach the image sensor, effectively taking out the harmful optical interference while maintaining close component placement.
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 new design results in smaller, lower power consumption sensors that do not require separate housings, enabling compact integration and efficient light measurement.
Implementation Method 1
a light source which emits light that reflects off a target and returns to an image sensor
Implementation Method 2
light that reflects off a target and returns to an image sensor
Implementation Method 3
an opaque wall blocks direct light paths, allowing only reflected light to reach the image sensor
Implementation Method 4
detection of light from the light source which is reflected by the target back to a detector
Data Source
AI summary
Time-of-Flight (ToF) sensors and methods for making are disclosed. A light-emitting diode is adjacent to an image sensor, and they are separated by an opaque wall to block direct light paths. The ToF sensor is smaller in both area and height, and has reduced power consumption.