LCD Backlight Diodes for Optical Input

Solution Overview

Problem

Current optical input systems for electronic devices require separate cameras, leading to increased cost and package size due to the need for additional components, and there is a need for a more efficient method to capture images and detect light sources.

Innovation Solution

A system and method utilizing light emitting diodes (LEDs) in liquid crystal display (LCD) backlights that function as both light emitters and detectors, where the LEDs generate a voltage in response to incoming light, allowing for image capture and light source detection through a color filter-based scanning process, enabling the use of the LCD screen as an optical input device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separate cameras are used for optical input, then image capture capability is improved, but device complexity and package size increase

Engineering Contradiction:

Improveoptical input capabilityVSAvoidcomponent count

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The LCD display is designed to perform multiple functions: it serves as both the visual output display and the optical input sensor. The display pixels can detect reflected light and convert it to electrical signals, enabling the same component to handle both output and input optical functions, thereby eliminating the need for separate cameras and reducing overall device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the display function and optical sensing function into a single integrated component. The LCD display structure is modified to include photodetector elements that can detect reflected light, merging the output display and input sensing capabilities into one unified device, which reduces component count and simplifies the overall system architecture

Inventive Principle:

Principle #5Merging (Combining)

2Adaptability or versatility

If separate cameras are used for optical input, then image capture capability is improved, but package size increases

Engineering Contradiction:

Improveoptical input capabilityVSAvoidpackage size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The LCD display is designed to perform multiple functions: it serves as both the visual output display and the optical input sensor. The display pixels can detect reflected light and convert it to electrical signals, enabling the same component to handle both output and input optical functions, thereby eliminating the need for separate cameras and reducing overall device complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the display function and optical sensing function into a single integrated component. The LCD display structure is modified to include photodetector elements that can detect reflected light, merging the output display and input sensing capabilities into one unified device, which reduces component count and simplifies the overall system architecture

Inventive Principle:

Principle #5Merging (Combining)

3Device complexity

If LEDs are used for both light emission and detection, then device complexity is reduced, but measurement precision may be affected

Engineering Contradiction:

Improvecomponent countVSAvoidlight detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The LCD display is divided into separate pixel elements that can be independently controlled. Each pixel can function as either a light-emitting element or a light-detecting element, and the segmentation allows the system to switch between emission and detection modes without interference, maintaining measurement precision while reducing overall device complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The display pixels are designed to be dynamically switchable between emission mode and detection mode. The system can transition between these states based on operational requirements, allowing the same physical structure to serve different functions at different times, thereby reducing component count while maintaining precision through controlled operational states

Inventive Principle:

Principle #15Dynamics

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 approach allows for a smaller form factor and reduced component count by leveraging existing LCD technology, enabling image capture and light source detection without additional cameras, while also enabling distance measurement and triangulation for location determination.

Implementation Method 1

The diode may generate a voltage in response to light passing through the color filter and arriving on the diode

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS11681396B2Optical input diodes

Publication Date: 2023.06.20 PANASONIC AUTOMOTIVE SYSTEMS AMERICA LLC

AI summary

Examples of the present disclosure relate to a device, method, and system for optical input diodes. A liquid crystal display (LCD) backlight device may include a processor and a color filter of a pixel including at least one of a red filter, a green filter, or a blue filter. The LCD backlight device may also include a diode to emit light through the color filter in response to being driven by the processor. The diode may generate a voltage in response to light passing through the color filter and arriving on the diode, where an image value may be calculated as a function of the voltage generated and a color filter value of the color filter.