Color-Separating Lens Array for Filterless Image Sensor Pixels
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Solution Overview
Problem
Image sensors using color filters suffer from low light utilization efficiency due to absorption of light outside the corresponding color, resulting in significant light loss.
Innovation Solution
Employ a color separating lens array that focuses incident light separately according to its wavelength, using nanoposts to create distinct phase profiles for different wavelengths, allowing each pixel to capture specific colors without the need for color filters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a color filter is used to sense the color of incident light, then the color detection function is achieved, but the light utilization efficiency deteriorates due to absorption of light outside the corresponding color
Solution Approach 1:
The incident light is segmented by wavelength using the color separating lens array, which divides different wavelength ranges into different spatial directions. This allows each pixel to receive only the specific wavelength range it needs to detect, eliminating the need for color filters that absorb other wavelengths and thereby improving light utilization efficiency while maintaining color detection accuracy
Solution Approach 2:
The color separating lens array acts as an intermediary component between the incident light and the pixel array. It performs wavelength-based spatial separation before the light reaches the pixels, enabling direct detection without requiring color filters on the pixels themselves, thus resolving the contradiction between color detection and light efficiency
2Loss of energy
If a color separating lens array is used to improve light utilization efficiency, then the light loss is reduced, but the device complexity increases due to the additional optical component
Solution Approach 1:
The patent replaces the conventional color filter mechanism (which relies on selective absorption) with a color separating lens array that uses refraction and spatial separation. This substitution achieves better light utilization by directing different wavelengths to different pixels without absorption loss, while the lens array structure can be integrated into existing sensor architectures to minimize added complexity
3Device complexity
If each pixel captures all wavelengths through a color filter, then the pixel structure remains simple, but the auto-focusing performance deteriorates due to light loss
Solution Approach 1:
The color separating lens array enables pixels to serve multiple functions: they can detect specific color information through wavelength-selective routing while simultaneously providing sufficient light intensity for accurate auto-focusing. By eliminating the need for color filters that absorb light, each pixel receives adequate light for both color detection and focus measurement, achieving multi-functionality without compromising performance
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
Improves light utilization efficiency and enhances auto-focusing performance by enabling each pixel to capture targeted wavelengths effectively, reducing light loss and improving image sensor performance.
Implementation Method 1
a color separating lens array 130 for condensing the incident light Li differently according to wavelengths
Implementation Method 2
Each of the plurality of nanoposts NP changes a phase of the incident light Li differently according to incident locations
Data Source
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AI summary
Provided are an image sensor including a color separating lens array and an electronic apparatus. The image sensor includes: a sensor substrate including a plurality of first pixels and a plurality of second pixels, wherein each of the first pixels includes a plurality of photosensitive cells that are two-dimensionally arranged in a first direction and a second direction, and, a first pixel of a first group includes a first edge region and a second edge region that are arranged at opposite edges of the first pixel in the first direction and outputs first and second photosensitive signals with respect to the light incident on the first and second edge regions.