Display Integrated Camera Array for Dead Zone Detection

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Solution Overview

Problem

Conventional computing devices face challenges in determining user input, such as gestures and motions, when the user's hand or finger is outside the field of view of the camera, resulting in a 'dead zone' where input cannot be accurately detected.

Innovation Solution

A camera array is integrated behind the display screen, using low-resolution photodiodes to capture ambient or infrared light passing through the screen, allowing for the detection of objects near the screen independent of the screen's operation, and emitting IR light to determine the location and orientation of the user's finger within the dead zone.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If a single camera is used to capture user gestures, then the device structure is simple, but the detection range is limited and dead zones are created

Engineering Contradiction:
Improvedetection rangeVSAvoidcamera array structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent divides the detection system into multiple camera elements arranged in an array behind the display screen. Each camera element captures a portion of the user's hand or finger, and the combined data from all elements creates a complete detection coverage across the entire screen area, eliminating dead zones while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-camera 2D detection approach to a multi-camera array system that effectively adds depth information through the display screen barrier. By positioning cameras behind the screen and using the screen as an optical interface, the system achieves 3D spatial detection capability without requiring complex external sensor arrangements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Measurement precision

If lenses are used in the camera array to improve image quality, then detection accuracy improves, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvefinger position detection accuracyVSAvoidoptical system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts and removes the lens component from the camera array design. By eliminating lenses, the system reduces optical complexity, manufacturing costs, and potential failure points while maintaining sufficient detection accuracy through the computational processing of images from multiple camera elements.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/optical focusing system (lenses) with a computational image processing system. The array of lensless camera elements captures spatial information that is then processed algorithmically to determine precise finger position and gesture, substituting complex optical mechanics with computational methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If the display screen is always on to provide user interface, then user interaction is continuous, but ambient light detection is blocked

Engineering Contradiction:
Improveuser interaction capabilityVSAvoidambient light for detection
Core Design Contradiction:
Ease of operationVSIllumination intensity

Solution Approach 1:

The patent implements periodic action by synchronizing the camera array operation with the display screen refresh cycle. The cameras capture images during the brief intervals when the screen is not actively displaying content (during refresh periods or backlight off-times), allowing ambient light detection to occur periodically without compromising continuous user interaction capability.

Inventive Principle:
Principle #19Periodic action

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 extends the detection range beyond the camera's field of view, enabling accurate determination of finger position and motion within the dead zone, improving user input accuracy and reducing the need for lenses, which simplifies device design and reduces costs.

Implementation Method 1

using low-resolution photodiodes to capture ambient or infrared light passing through the screen

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 2

emitting IR light to determine the location and orientation of the user's finger within the dead zone

Methodology Applied
Scientific EffectInfrared Radiation: Infrared Radiation

Data Source

PatentEP2898399B1Display integrated camera array
Publication Date: 2019.11.06 AMAZON TECH INC
  • EP2898399B1 patent drawingFigure 1
  • EP2898399B1 patent drawingFigure 2(a)~2(c)
  • EP2898399B1 patent drawingFigure 3(a)~3(f)

AI summary

Motions or gestures can provide input to an electronic device by capturing images of a feature used to provide the motions or gestures, then analyzing the images. Conventional cameras have a limited field of view, creating a "dead zone" near the device that is outside the field of view. Various embodiments utilize an array of detectors positioned behind a display screen that are configured to operate as a large, low resolution camera. The array can resolve objects within a distance of the device sufficient to cover at least a portion of the dead zone. In some embodiments the device can include one or more infrared (IR) emitters to emit IR light that can be reflected by an object in the dead zone and detected by the detectors. The use of multiple emitters at different locations enables at least some depth information to be determined from the array images.