Dual-Mode Image Sensor With Segmented Pixel Regions
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Solution Overview
Problem
Conventional image sensors for dual-use cameras, which require sensitivity to both visible and infrared/near-infrared wavelengths, face challenges in achieving high resolution and accurate color reproduction due to interference from infrared wavelengths, especially in outdoor conditions, and are limited by size, weight, and power constraints in mobile devices.
Innovation Solution
The development of an image sensor with a pixel array comprising two regions: one sensitive to visible wavelengths and another sensitive to infrared/near-infrared wavelengths, with a higher pixel density in the infrared region and strategically located to minimize distortion, allowing for dual-use functionality in biometric authentication and photography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If every pixel is made sensitive to infrared wavelengths, then infrared image resolution is improved, but visible color reproduction accuracy deteriorates under strong infrared conditions
Solution Approach 1:
The pixel array is divided into two distinct regions: a first region with pixels sensitive to both visible and infrared wavelengths for color imaging, and a second region with pixels sensitive primarily to infrared wavelengths for infrared imaging. This segmentation allows each region to be optimized for its specific function, resolving the contradiction between infrared resolution and visible color accuracy.
Solution Approach 2:
Different regions of the pixel array are assigned different spectral sensitivity characteristics. The first region has dual sensitivity for color photography, while the second region has enhanced infrared sensitivity for biometric authentication. This local differentiation enables each zone to perform its specialized function without interfering with the other.
2Measurement precision
If pixels are made highly sensitive to infrared wavelengths, then infrared detection capability is improved, but interference with visible color imaging increases under outdoor conditions
Solution Approach 1:
By segmenting the pixel array into regions with different spectral sensitivities, the patent isolates the high-infrared-sensitivity pixels to a specific region, preventing them from interfering with visible color imaging in other regions while maintaining strong infrared detection capability where needed.
Solution Approach 2:
The patent applies local quality by making only specific regions (second region) highly sensitive to infrared wavelengths, while other regions (first region) maintain balanced sensitivity for visible imaging. This localized approach eliminates infrared interference in color-critical areas while preserving infrared detection capability in dedicated areas.
3Adaptability or versatility
If dual-use cameras are implemented in mobile devices, then functionality is improved, but size and power consumption constraints are worsened
Solution Approach 1:
The patent merges color imaging and infrared imaging capabilities into a single pixel array sensor, eliminating the need for separate sensors. By integrating both functions in one component with spatially differentiated pixel regions, the design reduces device size, weight, and complexity while maintaining dual functionality for photography and biometric authentication.
Solution Approach 2:
The pixel array is designed with multi-functionality, where different regions serve different purposes: one region for visible color imaging and another for infrared imaging. This universal design allows a single sensor to perform both photography and biometric authentication functions, reducing the need for multiple separate components in mobile devices.
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 enhances image resolution and field of view while reducing distortion, enabling effective biometric recognition and photography in various conditions within the constraints of mobile devices.
Implementation Method 1
an array of pixels comprising at least a first pixel region and a second pixel region. The first pixel region comprises an array of pixels that are sensitive to visible wavelengths. The second pixel region comprises an array of pixels that are sensitive to a set of infrared or near-infrared wavelengths
Data Source
Figure 1A
Figure 1B
Figure 2A
AI summary
The invention provides apparatuses and methods relevant to image sensors configured for dual mode operation. The invention comprises an image sensor having an image sensor substrate having an array of pixels formed thereon. The array of pixels comprises (i) a first pixel region comprising a first array of pixels, which first array of pixels comprising pixels configured for peak sensitivity to wavelength(s) below 700 nm, and (ii) a second pixel region comprising a second array of pixels, which second array of pixels comprising pixels of a first pixel type and pixels of a second pixel type. Pixels of the first pixel type may be configured for peak sensitivity to wavelength(s) between 700 nm and 1000 nm. Pixels of the second pixel type may be configured for peak sensitivity to wavelength(s) below 700 nm. The invention additionally provides apparatuses incorporating the image sensor and methods for fabricating said image sensor.