Split-Electrode Imaging Pixel Structure for Accurate Phase Autofocus
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Solution Overview
Problem
The existing solid-state imaging devices face challenges in achieving high auto-focusing accuracy due to low light sensitivity, as light incident on the photodiode is not absorbed by the photoelectric conversion film but passes through it, resulting in weak incident light intensity.
Innovation Solution
A solid-state imaging device with a pixel structure where the photoelectric conversion film is interposed by upper and lower electrodes, with the upper electrode divided into two parts, allowing different voltages to be applied, enhancing light absorption and sensitivity for phase difference signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If light passes through the photoelectric conversion film to reach the photodiode, then the structure is simple, but the light intensity is weak and light reception sensitivity is low
Solution Approach 1:
The patent converts the previously wasted light that passed through the photoelectric conversion film into useful signal light by introducing a light guide layer that redirects this transmitted light to dedicated phase difference detection pixels, thereby improving light reception sensitivity without adding complex optical components
Solution Approach 2:
The light guide layer acts as an intermediary component between the photoelectric conversion film and the phase difference detection pixels, capturing the transmitted light and directing it to the appropriate detection regions, thus resolving the contradiction between structural simplicity and detection sensitivity
2Measurement precision
If the upper electrode is divided into multiple parts with different voltages, then light absorption and sensitivity are improved, but the device complexity increases
Solution Approach 1:
The upper electrode is segmented into multiple independent electrode regions (first upper electrode and second upper electrode) that can be controlled separately, allowing independent voltage application to different pixel groups for phase difference detection while maintaining overall structural integration
Solution Approach 2:
The divided upper electrode structure serves multiple functions: it acts as both a standard readout electrode for image pixels and as a phase difference detection electrode by applying different voltages to different regions, eliminating the need for separate detection electrode structures
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 improves auto-focusing accuracy by increasing the sensitivity of light reception, enabling more precise focus detection using phase difference signals.
Implementation Method 1
a photoelectric conversion portion having a structure where a photoelectric conversion film is interposed by an upper electrode on the photoelectric conversion film and a lower electrode under the photoelectric conversion film
Data Source
AI summary
The present disclosure relates to a solid-state imaging device, a method for driving the solid-state imaging device, and an electronic device capable of improving auto-focusing accuracy by using a phase difference signal obtained by using a photoelectric conversion film. The solid-state imaging device includes a pixel including a photoelectric conversion portion having a structure where a photoelectric conversion film is interposed by an upper electrode on the photoelectric conversion film and a lower electrode under the photoelectric conversion film. The upper electrode is divided into a first upper electrode and a second upper electrode. The present disclosure can be applied to, for example, a solid-state imaging device or the like.