Blood Trailing Flashlight With Spectral Filter
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Solution Overview
Problem
Traditional light sources are not optimized for the optical properties of blood or human vision, making it difficult to distinguish blood from other colors, especially at night, and application-specific lights with additive methods can create distracting colored interference shadows.
Innovation Solution
A light-emitting device with a white light source and a filter that progressively attenuates wavelengths up to 618 nm, allowing blood red colors to stand out in contrast to non-blood red colors, while minimizing interference shadows, using materials like Didymium glass or amethyst contrast enhancement glass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional white light sources (incandescent, LED) are used to illuminate blood at night, then the overall illumination intensity is sufficient, but the blood red colors cannot be distinguished from other colors due to broad spectrum flooding
Solution Approach 1:
The patent segments the broad white light spectrum into specific wavelength bands using optical filters. The filter transmits wavelengths above 618 nm (red portion) while attenuating wavelengths below this threshold, effectively dividing the spectrum to isolate the blood-reflective wavelengths. This segmentation allows the blood's characteristic red reflection to stand out against the darkened background of other colors.
Solution Approach 2:
The patent applies local quality by creating a non-uniform spectral distribution where specific wavelength regions are enhanced (above 618 nm) while others are suppressed (below 618 nm). This localized spectral enhancement targets the specific optical property of blood (reflecting red wavelengths) without uniformly affecting the entire spectrum, thereby improving blood detectability while maintaining overall illumination.
2Measurement precision
If application-specific light sources with additive methods (combinations of colored LEDs) are used to enhance blood detection, then blood visibility is improved, but colored interference shadows are created that cause significant distraction
Solution Approach 1:
Instead of using additive methods (combining multiple colored light sources) to enhance blood detection, the patent employs subtractive filtering. It starts with white light containing the full spectrum and removes wavelengths below 618 nm, keeping only the red portion that blood reflects. This inverted approach (subtraction rather than addition) achieves blood enhancement without creating the colored interference shadows that plague additive methods.
Solution Approach 2:
The patent extracts the harmful colored interference component by filtering out wavelengths below 618 nm. The optical filter selectively removes the problematic blue, green, yellow, and orange portions of the spectrum that cause distracting colored shadows, while retaining the beneficial red wavelengths above 618 nm that enhance blood visibility. This extraction eliminates the harmful side effect while preserving the useful function.
3Power
If high intensity white light sources are used to illuminate the scene, then maximum light output is achieved, but the human eye becomes saturated making color distinction difficult
Solution Approach 1:
The patent changes the spectral parameter of the light output by using a filter with a specific cutoff wavelength (618 nm). This parameter change transforms the broad-spectrum white light into a spectrally-selective red-enriched light. The filter modifies the light's wavelength distribution to emphasize the red portion (above 618 nm) while suppressing other wavelengths, thereby preventing eye saturation from broad spectrum flooding while maintaining high intensity in the blood-detective wavelength range.
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
Enhances the visibility of blood red colors by optimizing the light spectrum to the reflective properties of blood and human vision, reducing distractions from colored shadows and maintaining maximum light intensity.
Implementation Method 1
a filter configured to progressively attenuate portions of the white light having wavelengths up to a transition wavelength that exists within a red light spectrum of the white light. The transition wavelength is optimally about 614 nm. The filter may include glass mixed with at least one rare earth mineral, or include amethyst contrast enhancement (ACE) glass.
Data Source
AI summary
A light-emitting device configured to illuminate blood includes a white light source configured to emit white light, and a filter configured to progressively attenuate portions of the white light having wavelengths up to a transition wavelength within a red light spectrum of the white light. The transition wavelength may be in the range of about 610 nm to about 618 nm.