Optical Waveguide Layer for Small-Pixel Light Condensing
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Solution Overview
Problem
The challenge is to enhance the light condensing property in the light detection layer of solid-state imaging elements, particularly as pixel size reduction leads to decreased light incidence and brightness, and existing technologies like those disclosed in JP2013-118295A and JP2005-142510A still have room for improvement in this aspect.
Innovation Solution
A structural body comprising a light detection layer, a color separation layer, and an optical waveguide layer that transmits light at an angle of 0° to 40° with respect to the normal line of the light detection layer, effectively changing the incident light angle to 0° to 1°, thereby improving light condensing efficiency, and optionally including a microlens and a flattening layer to further enhance light focusing and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size of the color separation layer is reduced to increase resolution, then the number of pixels increases, but the light condensing property in the light detection layer deteriorates and the amount of incident light decreases
Solution Approach 1:
The patent introduces a light condensing layer as an intermediary component between the color separation layer and the light detection layer. This layer has a higher refractive index than both adjacent layers, creating refractive index differences that enable effective light condensing. The light condensing layer acts as a mediator that redirects obliquely incident light from reduced-size pixels toward the normal direction, ensuring sufficient light reaches the light detection layer despite the smaller pixel aperture
Solution Approach 2:
The patent utilizes changes in refractive index parameters to achieve light condensing. By designing the light condensing layer with a refractive index higher than both the color separation layer and the light detection layer, the patent creates optimal refractive index contrasts at the interfaces. This parameter optimization enables effective light redirection and condensing, compensating for the reduced light gathering capability of smaller pixels
2Measurement precision
If the pixel size of the color separation layer is reduced to increase resolution, then the number of pixels increases, but brightness decreases due to reduced light incidence
Solution Approach 1:
The light condensing layer serves as a mediator that captures light from the color separation layer and redirects it toward the light detection layer. By having a higher refractive index than the adjacent layers, it creates the necessary refractive index difference to bend and concentrate light paths, ensuring that even with smaller pixel sizes, sufficient light reaches the detection layer to maintain brightness
Solution Approach 2:
The patent employs a microlens on the light incident side of the color separation layer to pre-concentrate incident light before it enters the color separation layer. This curved optical element helps gather oblique light rays and directs them toward the pixel aperture, compensating for the reduced light gathering area of smaller pixels and maintaining overall brightness
3Object-affected harmful factors
If existing anti-reflection film structures are used, then reflection reduction is achieved, but light condensing property and detection uniformity have room for improvement
Solution Approach 1:
The patent designs the light condensing layer to perform multiple functions simultaneously: it acts as an anti-reflection layer by having a refractive index between the color separation layer and light detection layer, reducing interface reflections; at the same time, it functions as a light condensing element by having a higher refractive index than the light detection layer, redirecting oblique light toward the normal direction. This multi-functionality eliminates the need for separate anti-reflection and light condensing structures, improving both reflection reduction and light detection uniformity
Solution Approach 2:
The patent employs a composite layer structure where the light condensing layer is positioned between the color separation layer and light detection layer. This composite structure combines the anti-reflection function (through refractive index matching) and light condensing function (through refractive index difference) in a single integrated layer, achieving both reflection reduction and improved light detection uniformity more effectively than separate layers
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 proposed solution significantly improves light condensing property in the light detection layer, reducing sensitivity shading and allowing for a thinner, more efficient solid-state imaging element with enhanced light detection uniformity and reduced light leakage, even when irradiated at oblique angles.
Implementation Method 1
an optical waveguide layer which is a layer that transmits light incident at an angle of 0° to 40° with respect to a normal line of a light receiving surface of the light detection layer by changing a traveling angle of the incident light to an angle of 0° to 1° with respect to the normal line of the light receiving surface of the light detection layer
Implementation Method 2
a microlens provided on the light incident side of the color separation layer
Data Source
AI summary
Provided are a structural body including: a light detection layer 10, a color separation layer 20 provided on a light incident side of the light detection layer 10, and an optical waveguide layer 30 provided on the light incident side of the light detection layer 10 and provided on at least one selected from a light incident side of the color separation layer 20 or a light transmitting side of the color separation layer 20, in which the optical waveguide layer 30 is a layer which transmits light incident at an angle of 0° to 40° with respect to a normal line of a light receiving surface 10a of the light detection layer 10 by changing a traveling angle of the incident light to an angle of 0° to 1° with respect to the normal line of the light receiving surface 10a of the light detection layer 10; and a solid-state imaging element and an image display device including the structural body.