Solid-state imaging device pixel architecture
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Solution Overview
Problem
Existing solid-state imaging devices face issues with color mixture due to incident light in a slanting direction, which can be exacerbated by the use of microlenses that increase cost and thickness, and cause brightness shading.
Innovation Solution
A solid-state imaging device design where the distance from the photoelectric conversion film to the color filter (d) is less than the arrangement pitch (p) of the photoelectric conversion element, utilizing a thin photoelectric conversion film with a high light absorption factor, a protective film with high transmittance, and complementary color filters, all formed without a microlens, to prevent color mixture and maintain high sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a microlens is provided on the color filter to reduce color mixture, then color mixture is reduced, but manufacturing cost increases, thickness increases, and brightness shading occurs
Solution Approach 1:
The invention extracts and removes the microlens component from the optical system. By eliminating the microlens, the patent avoids the associated problems of increased manufacturing cost, increased thickness, and brightness shading, while still preventing color mixture through alternative means (optimizing the distance between photoelectric conversion film and color filter).
Solution Approach 2:
The invention changes the critical parameter of the distance between the photoelectric conversion film and the color filter. By optimizing this distance to be less than the arrangement pitch of photoelectric conversion elements, the patent prevents color mixture without requiring a microlens, thus resolving the contradiction between preventing color mixture and maintaining simple structure.
2Object-affected harmful factors
If the distance from photoelectric conversion film to color filter is increased to reduce color mixture, then color mixture is reduced, but sensitivity decreases due to light absorption before reaching the photoelectric conversion film
Solution Approach 1:
The invention optimizes the distance parameter between the photoelectric conversion film and color filter, setting it to be less than the arrangement pitch of photoelectric conversion elements. This parameter optimization simultaneously prevents color mixture (by blocking slanting light) and maintains high sensitivity (by ensuring sufficient light reaches the photoelectric conversion film), thus resolving the contradiction.
3Quantity of substance
If microminiaturization of circuit is pursued to increase number of pixels, then number of pixels increases, but manufacturing precision requirements increase and circuit complexity increases
Solution Approach 1:
The invention utilizes the spatial dimension between the photoelectric conversion film and color filter to prevent color mixture. By optimizing this vertical distance, the patent enables higher pixel density without requiring proportional miniaturization of horizontal circuit dimensions, thus increasing pixel count while maintaining manageable manufacturing precision requirements.
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 design effectively prevents color mixture and sensitivity loss from slanting light without the need for a microlens, reducing manufacturing costs and thickness, while maintaining high image quality and integration density of pixel parts.
Implementation Method 1
a photoelectric conversion film sandwiched between the lower electrode and the upper electrode
Implementation Method 2
the protective film has a light transmittance of 80% or more in wavelength 400 nm to 700 nm
Implementation Method 3
color filters divided for each pixel are formed on the upper electrodes in a one-to-one correspondence
Data Source
AI summary
A solid-state imaging device comprising a plurality of pixel parts each capable of obtaining one color signal, said plurality of pixel parts being arranged in the same plane, wherein each of the pixel parts comprises: a photoelectric conversion element comprising a lower electrode formed on or above a substrate, an upper electrode formed above the lower electrode and a photoelectric conversion film sandwiched between the lower electrode and the upper electrode; and a color filter formed on or above the upper electrode, wherein d<p where d is a distance from a lower face of the photoelectric conversion film to an upper face of the color filter and p is an arrangement pitch of the photoelectric conversion element.