Image Sensor Cover Glass for UV Absorption and IR Filtering
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Solution Overview
Problem
Optoelectronic image recording devices, such as cameras, suffer from aberrations due to sensitivity to infrared and ultraviolet light, leading to issues like faulty red color reproduction, blooming, and chromatic aberrations, which conventional UV barrier layers inadequately address, especially in compact devices like mirrorless system cameras.
Innovation Solution
A sensor unit with a cover unit comprising a UV absorption glass and an IR absorption glass, where the UV absorption glass absorbs ultraviolet radiation rather than reflecting it, reducing colored lens reflections and aberrations by removing unwanted radiation from the optical system, and the IR absorption glass acts as a short-pass filter to limit the infrared spectrum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a UV barrier layer is used to reflect ultraviolet radiation, then the spectral range is limited, but the reflectivity varies greatly with the angle of incidence and flat incident radiation is insufficiently reflected
Solution Approach 1:
The patent changes the fundamental parameter of UV radiation interaction from reflection to absorption. The cover glass is designed with UV-absorbing properties that work effectively across all angles of incidence, eliminating the angle-dependent performance variation inherent in reflective barrier layers.
Solution Approach 2:
The patent converts the harmful reflected UV radiation into absorbed energy that is dissipated as heat within the cover glass material. This transformation eliminates the problematic reflections that cause colored fringes and chromatic aberrations, particularly for flat incident radiation in compact camera designs.
2Object-affected harmful factors
If a reflective UV barrier layer is used, then spectral filtering is achieved, but colored lens reflections and chromatic aberrations occur due to reflected radiation
Solution Approach 1:
The patent fundamentally changes the interaction mechanism from reflection to absorption, thereby eliminating the generation of colored lens reflections. The absorbed UV energy is converted to heat and dissipated, preventing the formation of chromatic aberrations and purple fringing that occur with reflective barrier layers.
3Length of moving object
If the back focal length is reduced in compact image recording devices, then device compactness is improved, but flat incident radiation increases causing inadequate UV reflection
Solution Approach 1:
The patent changes the UV radiation handling mechanism from angle-dependent reflection to angle-independent absorption. This allows compact camera designs with reduced back focal lengths to effectively block UV radiation without requiring the barrier layer to reflect flat incident radiation, which is inherently difficult to achieve.
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 minimizes aberrations in the short-wave spectral range, reducing unnatural color fringes and improving image quality by ensuring that radiation is absorbed rather than reflected back onto the sensor, even at varying angles of incidence, thereby enhancing the image recording device's performance.
Implementation Method 1
the first absorption glass is configured as a UV absorption glass... a UV absorption glass, which does not reflect ultraviolet radiation but absorbs it
Implementation Method 2
the second absorption glass is configured as an IR absorption glass... an infrared absorption glass (IR absorption glass) that limits the electromagnetic radiation in the red spectral range incident on the cover glass structure in that radiation of the respective spectral range is absorbed in the absorption glass
Data Source
AI summary
A sensor unit for an image recording device comprises an optoelectronic image sensor and a cover unit arranged in front of the optoelectronic image sensor. The cover unit comprises a first absorption glass and a second absorption glass, wherein the first absorption glass is configured as a UV absorption glass and the second absorption glass is configured as an IR absorption glass.