Camera Module Refractive Index Adjustment Layer Ghost Suppression
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Solution Overview
Problem
Camera modules with auto-focus functions experience ghost or flare generation due to refractive index differences between air layers and infrared light cut filters, leading to image quality issues.
Innovation Solution
Incorporating a refractive index adjustment layer between the image sensor and the lens unit in the camera module, which can be a stacked lens structure with a variable focus lens and an infrared light cut filter, to eliminate gaps and reduce refractive index mismatches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an air layer is provided between the lens and the infrared light cut filter to enable auto-focus movement, then the lens can move along the optical axis, but light reflection occurs at the interface due to refractive index difference, generating ghost or flare
Solution Approach 1:
A refractive index adjustment layer is introduced as an intermediary between the lens and the infrared light cut filter. This layer has a refractive index that gradually transitions from the lens material to the filter material, reducing the abrupt refractive index difference at the interface. By acting as a mediator, it minimizes light reflection while allowing the air layer to remain for auto-focus movement.
Solution Approach 2:
The refractive index of the adjustment layer is specifically designed to be between that of the lens and the infrared light cut filter. By changing the refractive index parameter of the intermediate layer, the reflection coefficient at the interface is reduced according to the Fresnel equations, thereby suppressing ghost and flare generation while maintaining the air gap for focus adjustment.
2Object-generated harmful factors
If a refractive index adjustment layer is formed between the infrared light cut filter and the lens unit, then ghost and flare are suppressed, but the device structure becomes more complex
Solution Approach 1:
The refractive index adjustment layer is implemented as a thin film deposited on the surface of the infrared light cut filter. This thin film structure adds minimal physical thickness and complexity to the overall device while effectively addressing the light reflection issue. The film can be applied conformally to the filter surface without requiring significant structural modifications.
Solution Approach 2:
The adjustment layer is formed using a composite material structure, such as a multi-layer thin film or a gradient index material, that combines different material properties to achieve the desired refractive index transition. This composite approach allows optimization of both optical performance and structural integration within the existing camera module framework.
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 effectively suppresses the generation of ghosts and flares, enhancing image quality by minimizing light reflections and ensuring accurate light transmission.
Implementation Method 1
due to a difference in a refractive index between the air layer and the IRCF, light passing through the lens is reflected on a surface of the IRCF
Implementation Method 2
at least one refractive index adjustment layer that is formed between the image sensor and the lens unit
Data Source
AI summary
The present technology relates to a camera module, a method of manufacturing the same, and an electronic apparatus capable of suppressing generation of a ghost or a flare. The camera module includes an image sensor, a lens unit that is provided on a light receiving surface of the image sensor, and at least one refractive index adjustment layer that is formed between the image sensor and the lens unit. The present technology can be applied to, for example, a camera module including a complementary metal oxide semiconductor (CMOS) image sensor.