Display Proximity Sensing With Position-Based IR Thresholds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hand proximity detection systems for displays, particularly in automotive dashboards, suffer from erroneous detection of hand approaches due to strong infrared light reflections, often requiring dedicated LEDs that can interfere with operations on other devices and fail to accurately differentiate between intended display interactions and other device operations.
Innovation Solution
A proximity detection device using a plurality of infrared light sources arrayed along one side of the display surface outside the display, combined with light detectors and a sensitivity setting unit that adjusts detection sensitivity based on the intensity and position of reflected light, allowing for precise detection of hand approaches without dedicated LEDs towards the driver's seat, thereby reducing false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated infrared LED is used to emit infrared light toward the driver's seat, then the driver's operations on other devices can be distinguished from display operations, but the device complexity increases and may still fail to accurately differentiate between intended display interactions and other device operations
Solution Approach 1:
The patent divides the detection space into multiple regions by using an array of infrared LEDs along one side of the display and photodiodes arranged to detect reflected light from different spatial zones. This segmentation allows the system to distinguish between reflections from the driver's seat area and the passenger's seat area without requiring dedicated LEDs for each zone, reducing overall system complexity while maintaining detection accuracy
Solution Approach 2:
The patent applies different sensitivity thresholds to different detection regions. By calculating the center of gravity of the intensity distribution and comparing it against position-dependent thresholds, the system adapts its detection criteria locally - using lower thresholds in the driver's seat area and higher thresholds in the passenger's seat area, thereby improving reliability without uniform complexity increase
2Measurement precision
If the sensitivity of the proximity detection is increased to accurately detect hand approaches, then detection precision improves, but false positive detections increase due to strong infrared light reflections from other devices
Solution Approach 1:
The patent implements position-dependent sensitivity by calculating the center of gravity of the reflected light intensity distribution and applying different thresholds based on the estimated reflection position. When the center of gravity indicates a reflection from the driver's seat area, a lower threshold is applied; when it indicates the passenger's seat area, a higher threshold is applied. This local adaptation of detection criteria maintains high detection precision while reducing false positives
Solution Approach 2:
The system uses feedback from the intensity distribution pattern to dynamically adjust detection thresholds. By continuously monitoring the center of gravity position of reflected light and comparing it against known spatial patterns, the system adapts its sensitivity in real-time, improving measurement precision while filtering out false positives from strong reflections
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 solution effectively suppresses erroneous detection of hand approaches near the driver's seat by adjusting sensitivity settings according to the position and intensity of reflected infrared light, ensuring accurate detection of user interactions on the display while minimizing interference with other devices.
Implementation Method 1
a plurality of infrared light sources that are arrayed along a first side, which is one side of the display surface, outside the display surface of the display and emit infrared light passing the front of the display surface
Implementation Method 2
detects the user's approach to the display surface with a set sensitivity using an intensity of reflected light of the infrared light emitted by each of the infrared light sources detected by the light detector
Data Source
AI summary
Four infrared LEDs and two photodiodes PD are arranged below a lower side of a display surface in the order of an LED1, a PD1, an LED2, an LED3, a PD2, and an LED4. A detection signal A1 of the PD1 when the LED1 emits light, a detection signal A2 of the PD1 when the LED2 emits light, a detection signal A3 of the PD2 when the LED3 emits light, and a detection signal A4 of the PD2 when the LED4 emits light are used to estimate a reflection generation position in the left-right direction, and a threshold Th is set such that the threshold Th increases when the reflection generation position is on the left side, which is a driver's seat side. If the maximum value of A1, A2, A3, and A4 exceeds the threshold Th, the approach of the user's hand is detected.