Laser Illuminator for Rectangular Image Sensor Overfill
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Solution Overview
Problem
Imaging systems using CMOS or CCD image sensors face challenges in capturing sufficient light in enclosed spaces, particularly in applications like laparoscopic surgery, where ambient light is limited and heat generation is a concern, leading to noisy image signals and the need for improved illumination methods.
Innovation Solution
An illuminator apparatus utilizing an optical fiber to combine light beams of differing spectral properties, projecting a homogeneous illumination beam onto the object field, and using a controller to sequentially activate multiple light sources (such as red, green, and blue lasers) to optimize spectral characteristics and reduce specular reflections, while maintaining a polarized illumination to enhance image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional illumination methods are used in enclosed spaces, then ambient light is insufficient for imaging, but heat generation increases and image noise increases
Solution Approach 1:
The patent replaces conventional thermal illumination sources with laser-based illumination. Lasers provide high-intensity light with minimal heat generation in the imaged field, as the energy is delivered optically rather than through thermal radiation. This substitution resolves the contradiction by achieving bright illumination without proportional heat increase.
Solution Approach 2:
The patent changes the spectral parameters of illumination by using multiple lasers with different wavelengths (e.g., blue, green, red) instead of broad-spectrum thermal sources. This allows optimization of illumination intensity at specific wavelengths while controlling overall heat delivery, as laser energy can be precisely tuned to match sensor sensitivity peaks.
2Illumination intensity
If conventional illumination methods are used in enclosed spaces, then ambient light is insufficient for imaging, but image noise increases
Solution Approach 1:
The patent replaces conventional illumination with laser illumination that provides high intensity and coherence. This substitution improves image signal quality by delivering sufficient photons to the sensor without the noise characteristics of thermal sources, as lasers produce monochromatic, coherent light that can be precisely controlled.
Solution Approach 2:
The patent employs sequential activation of multiple lasers at different wavelengths, synchronizing them with the image sensor's frame rate. This periodic action allows each sensor element to capture optimal signal during its sensitive window while minimizing noise from other wavelengths, improving overall image quality through time-multiplexed illumination.
3Adaptability or versatility
If multiple light sources with differing spectral properties are combined, then spectral illumination characteristics are optimized, but device complexity increases
Solution Approach 1:
The patent combines multiple laser beams by nesting them spatially and temporally. Multiple lasers are activated sequentially, with each laser's beam path optimized to converge on the target field. This nesting approach allows complex spectral illumination to be achieved through layered, time-ordered activation rather than simultaneous complex optical combining, reducing overall system complexity.
Solution Approach 2:
The patent uses periodic activation of multiple lasers in sequence, synchronized with the image sensor's frame rate. This temporal multiplexing allows complex spectral illumination characteristics to be achieved through simple sequential switching rather than complex simultaneous beam combining optics, significantly reducing device complexity while maintaining spectral versatility.
4Reliability
If the illuminated region is sized to overfill the image sensor, then image quality is enhanced, but illumination energy is wasted
Solution Approach 1:
The patent applies local quality by illuminating different regions with different spectral characteristics tailored to local sensor sensitivity. By using multiple lasers with different wavelengths and activating them sequentially based on sensor element responsiveness, the system provides optimal illumination intensity and spectrum at each location, ensuring the sensor is overfilled with appropriate photons while minimizing wasted energy from mismatched spectral content.
Solution Approach 2:
The patent uses periodic activation of specific lasers synchronized with sensor readout timing. This allows the illumination to be precisely timed and spectrally matched to sensor sensitivity, ensuring that energy is delivered when and where it is most effective for overfilling the sensor, thereby reducing overall energy waste compared to continuous broad-spectrum illumination.
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 provides efficient and controlled illumination that enhances image quality by ensuring the image sensor is overfilled, reducing noise, and minimizing heat generation, thus improving the reliability and portability of imaging systems in constrained environments.
Implementation Method 1
an optical fiber having a proximal end disposed to receive a plurality of input light beams... the optical fiber being operable to transmit the light beams along the fiber to a distal end of the optical fiber
Implementation Method 2
an integrating element disposed to receive the light beams from the distal end of the fiber and combine the light beams to produce a generally homogenous illumination beam
Implementation Method 3
The plurality of light sources may include two or more of a red laser source, a green laser source, a blue laser source, and a tunable laser source
Data Source
AI summary
An illuminator apparatus and method for illuminating an object field imaged by a rectangular image sensor having a first aspect ratio is disclosed. The apparatus includes an optical fiber having a proximal end disposed to receive a plurality of input light beams, each light beam having differing spectral properties, the optical fiber being operable to transmit the light beams along the fiber to a distal end of the optical fiber. The apparatus also includes an integrating element disposed to receive the light beams from the distal end of the fiber and combine the light beams to produce a generally homogenous illumination beam at a rectangular output face of the integrating element. The apparatus further includes an illumination projector operable to project an image of the output face of the integrating element into the object field to produce a generally rectangular illuminated region of the object field substantially corresponding to the portion of the object field imaged by the rectangular image sensor.