Pupil Filter System for Phase Difference Detection
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Solution Overview
Problem
In imaging apparatuses, low color separation between color filters leads to crosstalk between red (R) and blue (B) images, increasing measurement errors in phase difference detection due to overlapping transmittance wavelength characteristics of color filters.
Innovation Solution
A measurement apparatus with a pupil filter system that includes first and second pupils, each transmitting specific wavelength bands, and a light source emitting non-overlapping red and blue illumination light, allowing for the acquisition of separate R and B images with reduced crosstalk through pixel signal processing and light source control units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color filters with overlapping transmittance wavelength characteristics are used to increase imaging sensitivity, then the amount of transmitted light increases and imaging sensitivity improves, but crosstalk occurs between R and B images leading to increased measurement error in phase difference detection
Solution Approach 1:
The patent divides the imaging system into separate channels with dedicated color filters for R and B images. By segmenting the wavelength bands transmitted to each pixel type and using separate processing paths, the system prevents crosstalk between color channels while maintaining high sensitivity through optimized filter characteristics in each segment.
Solution Approach 2:
The patent changes the parameters of color filters to achieve non-overlapping transmittance wavelength characteristics for R and B channels. By adjusting filter center wavelengths and bandwidths, the system eliminates spectral overlap that causes crosstalk, thereby improving phase difference measurement accuracy without sacrificing imaging sensitivity.
2Object-affected harmful factors
If color filters with non-overlapping transmittance wavelength characteristics are used to reduce crosstalk, then measurement error decreases, but the amount of transmitted light decreases and imaging sensitivity reduces
Solution Approach 1:
The patent segments the spectral range into distinct non-overlapping bands for R and B imaging, assigning specific wavelength ranges to each color channel. This segmentation eliminates crosstalk by ensuring that R pixels only receive R light and B pixels only receive B light, thereby improving measurement precision.
Solution Approach 2:
The patent optimizes the parameters of color filters (center wavelength, bandwidth, peak transmittance) within the non-overlapping spectral bands to maximize light transmission efficiency. By carefully tuning these parameters, the system achieves both crosstalk reduction and maintained imaging sensitivity.
3Ease of operation
If a Bayer image acquisition method is used to capture R and B images, then the imaging process is simplified, but crosstalk between R and B images increases due to low color separation
Solution Approach 1:
The patent segments the pixel array into spatially separated R and B pixel regions, each covered by corresponding color filters. This spatial segmentation combined with spectral filtering prevents crosstalk while maintaining the simplicity of single-shot Bayer pattern acquisition and processing.
Solution Approach 2:
The patent modifies the color filter parameters in the Bayer pattern to ensure non-overlapping transmittance characteristics. By adjusting filter spectral parameters, the system eliminates crosstalk in the simplified Bayer acquisition process while preserving ease of operation.
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
The solution effectively reduces measurement errors by minimizing crosstalk between R and B images, enhancing the accuracy of phase difference detection and image quality.
Implementation Method 1
The first pupil is capable of transmitting first light of a first wavelength band
Implementation Method 2
The second pupil is capable of transmitting second light of a second wavelength band different from the first wavelength band
Implementation Method 3
The plurality of first pixels generate first pixel signals based on third light of a third wavelength band transmitted through a first optical filter that is capable of transmitting the third light
Implementation Method 4
The plurality of second pixels generate second pixel signals based on fourth light of a fourth wavelength band transmitted through a second optical filter that is capable of transmitting the fourth light
Implementation Method 5
The light source outputs illumination light including only fifth light of a fifth wavelength band and sixth light of a sixth wavelength band not overlapping the fifth wavelength band
Implementation Method 6
The image acquiring unit acquires a first image based on the first pixel signals and a second image based on the second pixel signals from a captured image based on the first pixel signals and the second pixel signals
Implementation Method 7
The measurement unit measuring a phase difference between the first image and the second image
Data Source
AI summary
In a measurement apparatus, a first pupil is capable of transmitting first light of a first wavelength band, and a second pupil is capable of transmitting second light of a second wavelength band. An imaging device includes a plurality of first pixels generating first pixel signals based on third light of a third wavelength band transmitted through a first optical filter that is capable of transmitting the third light. The imaging device further includes a plurality of second pixels generating second pixel signals based on fourth light of a fourth wavelength band transmitted through a second optical filter that is capable of transmitting the fourth light. A light source outputs illumination light including only fifth light of a fifth wavelength band and sixth light of a sixth wavelength band not overlapping the fifth wavelength band.