Semi-transparent Mirror Anti-reflection Coating Ghost Image Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Single-lens reflex cameras with semi-transparent mirrors suffer from multiple reflections, leading to ghost images and impaired autofocus performance, especially during continuous shooting and when using digital cameras where images can be easily enlarged.
Innovation Solution
An optical function device with a base material layer, a semi-transparent layer that reflects a predetermined ratio of incident light, and a reflection prevention layer formed on the opposite plane to prevent internal reflections, reducing high-order unwanted light and ghost images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a semi-transparent mirror is made as a fixed-type to enable continuous autofocus and viewing during exposure, then autofocus performance and continuous shooting capability are improved, but multiple reflections occur within the mirror causing ghost images
Solution Approach 1:
The patent applies anti-reflection coatings to the surfaces of the semi-transparent mirror to convert the harmful effect of reflections into a beneficial reduction of ghost images. The anti-reflection coatings are designed with specific refractive indices and thicknesses to minimize multiple reflections while maintaining the mirror's semi-transparent properties for continuous autofocus operation.
Solution Approach 2:
The semi-transparent mirror is constructed as a composite structure combining the reflective layer with anti-reflection coating layers. This composite design allows the mirror to simultaneously provide the necessary reflection for autofocus sensing and transmission for continuous viewing, while the anti-reflection coatings suppress unwanted multiple reflections that cause ghost images.
2Object-generated harmful factors
If multiple reflection prevention measures are implemented, then ghost images are reduced, but device complexity increases
Solution Approach 1:
The patent reduces multiple reflections by changing the optical parameters of existing surfaces through anti-reflection coatings rather than adding complex optical elements. The coatings modify the refractive index and surface properties to minimize reflections, achieving ghost image reduction while maintaining relatively simple device structure.
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 solution effectively suppresses multiple reflections within the optical function device, preventing ghost images and enhancing autofocus performance by ensuring accurate reflection angles and reducing warping, thus improving image quality and autofocus accuracy.
Implementation Method 1
the semi-transparent layer reflecting light of incident light at a ratio determined in advance and passing remaining light
Implementation Method 2
a reflection prevention layer formed on a principal plane opposite to the principal plane of the base material layer with respect to the base material layer, the reflection prevention layer preventing reflection of the light passing through the base material layer
Data Source
AI summary
An optical function device includes a base material layer, a semi-transparent layer formed on a principal plane of the base material layer, the semi-transparent layer reflecting light of incident light at a ratio determined in advance and passing remaining light; and a reflection prevention layer formed on a principal plane opposite to the principal plane of the base material layer with respect to the base material layer, the reflection prevention layer preventing reflection of the light passing through the base material layer. The image-capturing device includes an optical function device, a first light receiving device for receiving transmission light from the optical function device, and a second light receiving device for receiving reflection light from the optical function device.