Refractive Index Layer Reflection Interface for Camera Ghost Rings
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Solution Overview
Problem
Small form factor cameras, such as those in smartphones, often suffer from undesirable artifacts like ghost rings or lens flares due to internal reflection of light off the image sensor and within the lenses, which degrade image quality.
Innovation Solution
Incorporating a reflection interface formed with a refractive index layer proximate to the image sensor, which has a lower index of refraction than surrounding materials, to reduce or eliminate internal reflections by reflecting light back towards the image sensor before it can cause further propagation through the lens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If a concave lens is used to reduce field curvature, then field curvature is reduced, but ghost rings and lens flares are produced
Solution Approach 1:
A refractive index layer is introduced as an intermediary component between the concave lens and the image sensor. This layer has a refractive index that is lower than both the lens material and the image sensor substrate, creating a gradient that reduces internal reflections. The refractive index layer acts as a mediator that allows the concave lens to maintain its field curvature correction function while minimizing the harmful ghost rings and lens flares caused by internal reflections.
Solution Approach 2:
The refractive index of the material between the concave lens and image sensor is changed by introducing a specialized refractive index layer. This layer has a specifically engineered refractive index that is lower than both surrounding materials, creating an optical parameter gradient that reduces internal reflections. This parameter change allows the system to maintain field curvature correction while reducing harmful optical artifacts.
2Reliability
If internal reflection is allowed to occur, then light can be reflected back towards the image sensor, but artifacts such as ghost rings are created
Solution Approach 1:
The refractive index layer converts the harmful internal reflections into beneficial controlled reflections. By engineering the refractive index gradient, the layer causes light to reflect back towards the image sensor in a controlled manner, concentrating the reflected light at the image sensor rather than allowing it to propagate through the lens system and create artifacts. This transforms the harmful reflection effect into a beneficial light control mechanism.
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 solution effectively minimizes the size and location of artifacts, ensuring they coincide with the light source, thereby improving image quality by preventing ghost rings from extending beyond the light source's footprint in the captured image.
Implementation Method 1
a reflection interface formed with a refractive index layer proximate to the image sensor... reflecting light back towards the image sensor
Implementation Method 2
refractive index layer... has a lower index of refraction than surrounding materials
Data Source
AI summary
Various embodiments disclosed herein include camera equipment having a refractive index layer that causes internal reflection close to an image sensor of the camera. In some examples, internal reflection may occur at a boundary formed with the refractive index layer and located between an image sensor and an upper surface of a lens of the camera. The boundary may be formed between the refractive index layer and another material located between the refractive index layer and the image sensor, wherein the refractive index layer has a lower index of refraction than other material between the refractive index layer and the image sensor. The boundary formed with the refractive index layer may cause light to be reflected back toward the image sensor to improve image quality of images captured by the image sensor.