Infrared Proximity Sensing Layout for False Hand Detection Control
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Solution Overview
Problem
Existing proximity detection systems for display surfaces, particularly in automotive dashboards, often result in erroneous detection of hand approaches due to strong infrared light reflections from dedicated LEDs, leading to incorrect operation recognition, especially near the driver's seat.
Innovation Solution
A proximity detection device utilizing a plurality of infrared light sources arrayed along one side of the display surface and light detectors outside the surface, with a sensitivity setting unit that adjusts detection sensitivity based on the intensity distribution of reflected light to differentiate between valid hand approaches and other device operations, eliminating the need for a dedicated infrared LED towards the driver's seat.
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 are not mistakenly detected as operations on the display, but the system complexity increases and the cost increases
Solution Approach 1:
The detection area is divided into multiple regions (first detection area near driver's seat, second detection area near passenger's seat) with different sensitivity thresholds. The control unit selectively applies different threshold values based on the detected hand position region, thereby reducing false detections near the driver's seat without requiring additional hardware components.
Solution Approach 2:
The sensitivity threshold is dynamically adjusted based on the detected hand position. When a hand is detected in the first detection area (driver's side), a first threshold value is applied; when detected in the second detection area (passenger's side), a second threshold value is applied. This dynamic adjustment resolves the contradiction by adapting the detection criteria to the spatial context.
2Reliability
If a dedicated infrared LED is used to emit infrared light toward the driver's seat, then false operations recognition is suppressed, but the manufacturing cost increases
Solution Approach 1:
The existing infrared LEDs that are already part of the display's front illumination system are made to serve a dual function: providing display illumination and enabling proximity detection. By controlling these existing LEDs to emit infrared light in specific patterns, the system achieves reliable detection without adding dedicated infrared LEDs, thereby reducing manufacturing costs while maintaining detection accuracy.
Solution Approach 2:
The system uses its own existing infrared illumination components to perform the detection function that would otherwise require separate dedicated LEDs. The control unit manages the infrared emission from existing LEDs to create detection zones, making the system self-sufficient and eliminating the need for additional hardware components.
3Measurement precision
If the detection sensitivity is increased to detect hand approaches accurately, then hand approach detection accuracy improves, but erroneous detection of other device operations increases
Solution Approach 1:
Different detection sensitivity levels are applied to different spatial regions. The first detection area (driver's side) uses a first sensitivity threshold, while the second detection area (passenger's side) uses a second sensitivity threshold. This local differentiation allows high sensitivity where needed while maintaining reliability in other areas, resolving the contradiction between detection accuracy and false positive rates.
Solution Approach 2:
The detection space is segmented into multiple zones with different operational characteristics. By dividing the detection area and assigning different threshold values to each zone, the system can maintain high detection sensitivity in the passenger area while using lower sensitivity in the driver area to avoid false detections, thus resolving the contradiction locally in each segment.
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 configuration effectively suppresses erroneous detections near the driver's seat by setting lower sensitivity in that area, ensuring accurate hand approach detection without using a dedicated infrared LED, thereby preventing false operations recognition.
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
an intensity of reflected light of the infrared light emitted by each of the infrared light sources detected by the light detector
Data Source
Figure 1
Figure 2
Figure 3A~3D
AI summary
To provide a proximity detection device (3) which does not erroneously detect an operation on another device as an approach of a user's hand to a display surface. Four infrared LEDs and two photodiodes PD are arranged slightly below a lower side of a display surface in the order of an LED 1, a PD 1, an LED 2, an LED 3, a PD 2, and an LED 4. A detection signal A1 of the PD 1 when the LED 1 emits light, a detection signal A2 of the PD 1 when the LED 2 emits light, a detection signal A3 of the PD 2 when the LED 3 emits light, and a detection signal A4 of the PD 2 when the LED 4 emits light are used to estimate a reflection generation position in the left-right direction from A1, A2, A3, and A4, 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, according to the reflection generation position in the left-right direction. Then, if the maximum value of A1, A2, A3, and A4 exceeds the threshold Th, the approach of the user's hand is detected.