Imaging Instrument Inclined Optical Component Mask Stray Light
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Solution Overview
Problem
Imaging instruments face a reduction in contrast and precision due to stray light rays generated by residual reflection on additional optical components and the photosensitive surface of the image sensor, particularly at wavelengths corresponding to the limits of the spectral filtering window.
Innovation Solution
An imaging instrument is designed with a mask and an optical component having inclined faces to redirect stray rays outside the image sensor's field, ensuring that critical rays make angles less than those formed by all transmitted light rays, thus eliminating parasitic reflections and improving image contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an additional optical component (such as a spectral filter) is placed between the imaging optics and the image sensor, then spectral filtering capability is improved, but stray light rays are generated due to residual reflection on the filter faces and sensor surface, degrading image contrast
Solution Approach 1:
The invention extracts and removes the harmful stray light rays from the optical path by using a mask that blocks reflected rays before they reach the image sensor. The mask is positioned to intercept rays that have undergone unwanted reflections on the filter surfaces, effectively separating the useful transmitted light from the harmful reflected light.
Solution Approach 2:
The invention introduces a mask as an intermediary element between the optical filter and the image sensor. This mask serves as a mediator that selectively blocks stray light rays while allowing useful light to pass through, resolving the contradiction between maintaining spectral filtering and eliminating stray light.
2Object-affected harmful factors
If the photosensitive surface and optical component faces have anti-reflective treatments, then reflection is reduced, but residual reflective power remains significant at the limits of the spectral transmission window
Solution Approach 1:
The invention applies preliminary anti-action by positioning the mask to preemptively block stray light rays before they can reach the image sensor and cause contrast degradation. The mask is strategically placed to intercept reflected rays at their source, preventing them from affecting image quality at spectral transmission limits.
Solution Approach 2:
The invention applies local quality by making the mask selectively transparent - it allows useful light rays to pass through while blocking only the specific stray light rays that have undergone unwanted reflections. This localized control of light transmission addresses the reflection problem without affecting overall system performance.
3Use of energy by moving object
If interference filters are used to achieve high transmission at the center of the spectral window, then transmission efficiency is improved, but reflection value becomes significant at the limits of the spectral transmission window, generating troublesome stray rays
Solution Approach 1:
The invention converts the harmful stray rays generated by interference filters into a manageable problem by using the mask to redirect and block these rays. The mask transforms the unwanted reflected light into a controlled situation where stray rays are prevented from reaching the sensor, thereby maintaining the high transmission efficiency benefit of interference filters while eliminating their harmful side effect.
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 stray rays, enhancing the contrast and precision of images captured by the image sensor by ensuring that critical rays are oriented outside the beam limits set by the pupil of the imaging optics, thereby improving the overall image quality.
Implementation Method 1
an optical component which is fixedly located on a path of the light rays between the imaging optic and the image sensor, this optical component comprising a portion of a refractive material and at least partially transparent for the light rays
Implementation Method 2
the faces of such an additional optical component, as well as the photosensitive surface of the image sensor, each have a residual reflective power
Data Source
Figure 1
Figure 2a~2d
Figure 3a
AI summary
An imaging instrument includes an optical component (3) located between an imaging optic (1) and an image sensor (2). It further includes a mask (4) intermediate between the optical component and the image sensor. Faces (FE, FS) of the optical component are inclined such that, in combination with a suitable aperture of the mask, light rays resulting from a reflection on the image sensor followed by at least one other reflection on one of the faces of the optical component are suppressed.