TOF Camera Module Light Emission Segmentation for Depth Accuracy
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Solution Overview
Problem
TOF camera modules face safety issues due to high wavelength light usage, accuracy reduction at long distances, and challenges in manufacturing small and lightweight designs with precise light control for depth information measurement.
Innovation Solution
A camera module with a light emitting unit comprising multiple light sources at different heights and diffractive optical elements, allowing for optimal light output control based on object distance without requiring complex actuators, thereby reducing light intensity on sensitive areas and enabling accurate depth measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TOF camera uses high wavelength light to measure depth information, then depth measurement capability is improved, but safety issues arise due to light entering sensitive areas such as eyes and skin
Solution Approach 1:
The light emitting unit is divided into multiple light sources (first light source, second light source, third light source) with different positions and functions. The first light source emits light for near objects, the second light source emits light for far objects, and the third light source provides additional illumination. This segmentation allows selective emission of light based on object distance, reducing unnecessary light exposure to sensitive areas while maintaining depth measurement capability.
2Measurement precision
If stronger light is emitted toward distant objects to improve depth information accuracy, then measurement precision is improved, but power consumption increases
Solution Approach 1:
The camera module dynamically selects which light source to activate based on the detected object distance. When an object is far away, the second light source (emitting stronger light) is activated to improve depth information accuracy. When an object is near, the first light source (emitting weaker light) is activated to reduce power consumption. This dynamic adaptation resolves the contradiction between measurement precision and power consumption.
3Adaptability or versatility
If carrier with magnets and coils is used to control light radiation angle, then adaptability is improved, but device complexity and volume increase
Solution Approach 1:
The patent replaces the mechanical carrier system (with magnets and coils for moving the carrier) with a stationary light emitting unit comprising multiple light sources at different positions. The different radiation angles are achieved through the geometric arrangement of light sources and optical members rather than mechanical movement. This substitution eliminates the complex carrier structure while maintaining adaptability in light radiation control.
4Adaptability or versatility
If carrier movement is used to control radiation angle, then adaptability is improved, but manufacturing precision requirements increase due to high precision moving distance control
Solution Approach 1:
Instead of requiring high-precision movement of a single carrier, the patent segments the light emitting function into multiple fixed light sources positioned at different heights and locations. Each light source is paired with optical members (lenses or reflectors) that provide the necessary radiation angle control. This segmentation converts a high-precision motion control problem into a simpler positional arrangement problem, reducing manufacturing precision requirements.
5Adaptability or versatility
If multiple light sources at different heights are used, then adaptability for different distances is improved, but device complexity increases
Solution Approach 1:
The multiple light sources (first, second, and third light sources) serve multiple functions: they provide illumination for different object distances, control radiation angles through their positional arrangement, and enable selective emission to improve both near and far object depth measurement. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity while achieving adaptability for different distances.
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 provides effective depth information measurement with reduced power consumption and safety enhancements by optimizing light output based on object distance, enabling a slim and efficient camera module design.
Implementation Method 1
a first optical member disposed on the plurality of light sources... an output light emitted through each of the first and second light sources is focused at different positions
Implementation Method 2
TOF (Time of Flight) camera is a technology that generates depth information by calculating the distance to the object by measuring the time when light emitted from a light source toward the object is reflected by the object and returns to the sensor
Implementation Method 3
a light receiving unit including an image sensor... measuring the time when light emitted from a light source toward the object is reflected by the object and returns to the sensor
Data Source
AI summary
A distance measurement camera module according to an embodiment includes a light emitting unit; and a light receiving unit including an image sensor, wherein the light emitting unit comprises: a plurality of light sources; and a first optical member disposed on the plurality of light sources, wherein the plurality of light sources comprises: a first light source spaced apart from the first optical member at a first height; and a second light source spaced apart from the first optical member at a second height, wherein the first height is smaller than the second height, and wherein an output light emitted through each of the first and second light sources is focused at different positions.