Compact Photoelectric Switch with Integrated LED and Heat Sink
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Solution Overview
Problem
Conventional color discrimination-type photoelectric switches face challenges in reducing size while maintaining high light projection intensity and accuracy, due to light amount and color irregularities, and have limited dynamic range and poor heat dissipation.
Innovation Solution
A photoelectric switch design utilizing a light emitting diode on a circuit board generating multiple color components, with a slit, light projecting and receiving lenses, and a heat dissipation system including a metal heat sink and thermally conductive materials to reduce size, suppress light and color irregularities, and enhance heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If three shell-type light emitting elements with wavelength selection-type dichroic mirrors and condensing lens are used, then color discrimination capability is improved, but device size increases
Solution Approach 1:
The patent merges three separate light emitting elements (red, green, blue LEDs) into a single integrated light emitting unit with a common lens. This consolidation eliminates the need for multiple wavelength selection-type dichroic mirrors and condensing lenses, significantly reducing the optical system size while maintaining color discrimination capability through sequential lighting control
Solution Approach 2:
The single light emitting unit serves multiple functions by sequentially emitting different color lights (red, green, blue) to perform color discrimination. The common lens handles all wavelength ranges, and the single optical path structure enables multi-color detection without requiring separate optical systems for each wavelength
2Illumination intensity
If drive current is increased to obtain high light projection intensity, then light projection intensity is improved, but heat dissipation becomes problematic
Solution Approach 1:
The patent introduces a reflector as an intermediary component that efficiently directs light from the LED toward the detection area. This reflector enhances light projection intensity by optimizing light distribution without requiring excessive drive current, thereby reducing heat generation while maintaining high light output effectiveness
3Measurement precision
If optical fiber cable is used to reduce light amount irregularity, then color discrimination accuracy is improved, but device size increases
Solution Approach 1:
The patent extracts and eliminates the optical fiber cable from the system by implementing an integrated LED-lens assembly that directly projects light onto the detection area. This removal of the optical fiber cable significantly reduces device size while the common lens ensures uniform light distribution across the detection area, maintaining color discrimination accuracy without requiring light amount irregularity correction
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 enables a compact photoelectric switch with improved light projection intensity, reduced light and color irregularities, and a wider dynamic range, while effectively managing heat, thus enhancing workpiece determination accuracy.
Implementation Method 1
a light emitting diode that is mounted on the surface of a circuit board and generates detected light containing two or more color components with different hues
Implementation Method 2
a slit having an opening that is smaller than a light emitting surface of the light emitting diode, and disposed such that the opening faces the light emitting surface
Implementation Method 3
a light projecting lens for concentrating the detected light, having passed through the opening, in the detection area
Implementation Method 4
a light receiving element for selectively receiving reflected light from the detection area in association with two or more specific wavelengths, to generate two or more light reception signals respectively corresponding to light receiving amounts of the respective specific wavelengths
Implementation Method 5
a light receiving lens for concentrating the reflected light from the detection area on the light receiving surface of the light receiving element
Implementation Method 6
a heat dissipation system including a metal heat sink and thermally conductive materials
Data Source
AI summary
There is provided a photoelectric switch capable of reducing a size of a whole device while suppressing light amount irregularity and color irregularity of detected light. The photoelectric switch includes: a surface mount LED, configured to generate a light containing a plurality of color components with different hues; an optical shield disposed between the surface mount LED and a light projecting lens to shield the light around an optical opening passing the light from the surface mount LED to the light projecting lens; a light receiving element configured to selectively receive the light to generate a plurality of light reception signals; a controller configured to control a light projecting amount of the surface mount LED based on the light reception signal.