Sequenced Illumination Pulses for Heat-Controlled Mark Reading
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Solution Overview
Problem
Conventional mark reading devices face issues with overheating of light sources due to excessive power consumption, leading to reduced lifespan and increased downtime, especially in handheld devices with limited power capacity, and require improved illumination methods to adapt to various mark types efficiently.
Innovation Solution
A composite light source with a sequence of illumination light pulses of different wavelength spectra, controlled by a control unit to maintain heat generation below a threshold, synchronized with image acquisition, allowing high-intensity illumination while minimizing power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If high-intensity continuous illumination is used to read various mark types, then reading capability is improved, but heat generation increases causing overheating and reduced light source lifespan
Solution Approach 1:
The patent applies periodic pulsed illumination instead of continuous illumination. The control unit activates the light source in periodic pulses with controlled duty cycles, allowing the light source to operate at high intensity during pulses while having cooling periods between pulses. This periodic action maintains reading capability during active pulses while preventing continuous heat accumulation that would reduce light source lifespan.
Solution Approach 2:
The patent implements dynamic control of illumination parameters including variable pulse width, variable frequency, and variable duty cycle. The control unit dynamically adjusts these parameters based on the specific reading task, mark type, and thermal conditions. This dynamic adaptation allows optimal balance between reading performance and heat management, extending light source lifespan while maintaining versatility.
2Illumination intensity
If high power is consumed to illuminate marks effectively, then illumination intensity is improved, but device size, weight, and power consumption increase
Solution Approach 1:
The patent uses periodic pulsed illumination where the light source operates at high intensity only during brief pulse intervals rather than continuously. The duty cycle is controlled to provide sufficient illumination intensity during pulses for effective mark reading, while the average power consumption is reduced during non-pulse intervals. This approach maintains effective illumination intensity while significantly reducing overall energy consumption in handheld devices.
3Power
If high intensity illumination pulses are delivered to excite luminescent materials, then luminescence excitation is improved, but heat generation in the light source increases
Solution Approach 1:
The patent delivers high-intensity illumination pulses in periodic sequences with controlled duration and frequency. During each pulse, sufficient power is delivered to effectively excite luminescent materials in security marks. Between pulses, the light source has cooling periods that allow heat dissipation, preventing excessive temperature accumulation. This periodic delivery pattern maintains effective luminescence excitation while controlling heat generation within safe thresholds.
Solution Approach 2:
The control unit preliminary determines the appropriate pulse parameters (width, frequency, duty cycle) based on the detected mark type and environmental conditions before delivering the illumination sequence. This preliminary action optimizes the balance between delivering sufficient power for luminescence excitation and managing heat generation, adjusting parameters in advance to prevent excessive temperature rise while ensuring effective excitation.
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 prevents overheating, extends the lifespan of the light source, reduces device size, weight, and power consumption, and enables efficient reading of various mark types, including luminescent materials, under varying environmental conditions.
Implementation Method 1
A luminescent material typically converts energy of an exciting radiation of a given wavelength into emitted light having another wavelength
Implementation Method 2
so-called 'fluorescence', which relates to prompt radiation emission upon excitation
Data Source
Figure 1A~2A
Figure 2B~3
Figure 4
AI summary
A reader operable to read a mark on a substrate, the reader comprising a power source, operable to deliver a variable drive current or voltage, a light source operable to illuminate said mark with a sequence of illumination light pulses of different wavelength spectra, an intensity of said illumination light pulses varying according to the delivered drive current or voltage, a light sensor operable to measure an intensity of light received from said mark and to deliver a corresponding light intensity signal, and a control unit operable to control said power source and light sensor to control timings of said illumination light pulses according to a switching pattern and timings to acquire said light intensity signal for synchronizing acquisition of said light intensity signal with said sequence of illumination light pulses, said control unit being further operable to adjust a duty cycle of said switching pattern so as to maintain heat generation associated to each illumination light pulse below a given threshold value.