LED standard intensity lamp

Abstract

The invention discloses an LED (light-emitting diode) standard intensity lamp, which realizes 240-1100nm continuous spectrum output through layered collaborative excitation of mixed fluorescent powder (CeF3, Eu < 2 + >: BAM, Ce < 3 + >: YAG and Ti < 3 + >: Al2O3), and ensures the stability of spectrum output by adopting a quartz lens focusing collimation light path design. The light source has the advantages of small size, low power consumption, long service life and the like, can replace the traditional deuterium lamp and halogen lamp, and is used for full-band calibration of spectrometers, remote sensing equipment and industrial detection systems.

Description

Technical Field

[0001] This invention belongs to the field of optical metrology technology, specifically relating to a full-band continuous spectrum standard light source covering ultraviolet-visible-near infrared, which is suitable for the calibration and standardization of spectrometers, photodetectors and multi-wavelength optical systems. Background Technology

[0002] Spectral intensity calibration is the foundation of optical measurement. Its core functions are twofold: first, to correct system errors through a standard light source and ensure measurement accuracy; and second, to support application needs in fields such as semiconductors, biomedicine, and autonomous driving and ensure instrument reliability.

[0003] Traditional spectral calibration light sources suffer from defects such as spectral discontinuities (e.g., a sudden drop in the ultraviolet band of xenon lamps and visible light band breaks in deuterium lamps), poor thermal stability leading to light intensity drift, large size, and high power consumption. Existing LED solutions still face spectral band breaks (missing ultraviolet / near-infrared bands) and temperature drift problems due to insufficient thermal stability of phosphors. Multi-lamp combination solutions are costly and have complex calibration processes, making it difficult to meet the modern high-precision wide-band calibration requirements.

[0004] In recent years, although LED technology has made significant breakthroughs in the lighting field, it still faces severe challenges in high-precision spectral calibration applications: 1. The narrow emission bandwidth of commercial phosphors leads to wide-band spectral fragmentation; 2. Thermal quenching effect causes efficiency decay and spectral peak shift; 3. The low external quantum efficiency of ultraviolet LEDs and the low conversion efficiency of phosphors result in ultraviolet radiation power that is 1-2 orders of magnitude lower than that of traditional light sources, which seriously restricts the process of practical application. Summary of the Invention

[0005] To address the aforementioned problems, this invention proposes a standard intensity LED lamp, the core innovation of which is described below.

[0006] 1. Optimized material combination to achieve segmented spectral synergistic excitation: A CeF3 fluorescent layer absorbs 254 nm excitation light to generate 260-400 nm broadband ultraviolet fluorescence, and LED residual light is used to enhance the 240-260 nm short-wave ultraviolet light; the visible light range (400-650 nm) is enhanced by Eu... 2+ :BAM and Ce 3+ The overlapping energy levels of YAG eliminate the traditional "blue light gap"; Ti is used in the near-infrared band (650-1100 nm). 3+ Al2O3 crystals extend the emission bandwidth to over 500 nm, breaking through the traditional near-infrared cutoff wavelength limitation and achieving seamless spectral coverage of 240-1100 nm.

[0007] 2. Thermal management: Based on aluminum / copper substrate, a high-efficiency heat dissipation architecture is designed, combined with airflow channel heat dissipation, to suppress the thermal quenching effect.

[0008] 3. Innovative optical system design: The LED chip is directly mounted using an aspherical quartz lens, which reduces interface reflection loss, compresses and reduces the beam divergence angle, improves the uniformity of the light spot, and focuses the excitation spot to within 4 mm; at the same time, a large NA quartz lens is used to collimate the output light of the phosphor layer, achieving high uniformity collimated output across the entire wavelength range (240-1100 nm). Beneficial effects

[0009] Comprehensive spectral coverage: output wavelength 240-1100 nm, spectral fluctuation ≤5% (measured value), meeting the requirements for spectrometer calibration.

[0010] Compact and portable design: The light source module has a volume of ≤Φ60 mm×50 mm and a power consumption of ≤5 W, making it suitable for various outdoor and laboratory applications. Detailed Implementation Implementation Method 1:

[0011] The core of the mixing and clamping packaging process is to achieve rapid assembly of the phosphor conversion layer through physical mixing and mechanical clamping, which is suitable for low-power scenarios.

[0012] Steps and Structure: 1. Phosphor Mixing: Mix commercially available CeF3 (25%), Eu... 2+ :BAM (35%), Ce 3+ :YAG (30%), Ti 3 + 1. Al2O3 (10%) is mixed according to the mass ratio and processed in a planetary shaker (300 rpm) for 2 hours to ensure uniform dispersion; 2. Substrate design: a sandwich structure is formed by double-sided polished quartz sheet and PTFE or aluminum alloy substrate, and the thickness of the fluorescent layer is controlled at 0.2-0.5mm; 3. Heat dissipation integration: the sandwich structure is fixed to the center of the aluminum alloy heat dissipation base by aluminum alloy pressure plate, and the temperature of the light source is maintained by the surrounding air heat dissipation channel.

[0013] Performance characteristics: The light source achieves continuous spectrum output of 240-1100nm.

[0014] Application scenarios: rapid prototyping in laboratories or calibration of portable spectrometers. Implementation Method Two:

[0015] The core of the ball milling, cold pressing, and sintering ceramic sheet process is to improve the density of the fluorescent layer through ball milling dispersion and cold pressing sintering, making it suitable for industrial-grade high-power applications.

[0016] Steps and Structure: 1. Material Pretreatment: Various phosphors (CeF3, Eu) 2+ :BAM、Ce 3+ :YAG、Ti 3+1. Mix Al2O3 according to the proportion in Embodiment 1, use ethanol as solvent, and wet ball mill for 4 hours using a planetary ball mill (zirconia grinding balls, ball-to-material ratio 5:1); 2. Molding and sintering: After drying the mixed slurry, cold isostatic pressing is used to form the molten blank. The molten blank is then sintered in an argon atmosphere for 2 hours to form a dense fluorescent ceramic sheet. The surface is polished to Ra≤0.1 μm; 3. Thermal management design: The ceramic sheet is bonded to an aluminum alloy substrate with silver paste. An aluminum alloy heat dissipation fin array is embedded in the substrate.

[0017] Performance characteristics: The ceramic sheet has high thermal conductivity and excellent thermal shock resistance.

[0018] Application scenario: Compatible with vehicle-mounted testing equipment. Implementation Method 3:

[0019] The core of the layered cold pressing-stacked architecture process is: independent layered sintering across the entire wavelength range, achieving dual optimization of spectral continuity and heat dissipation performance.

[0020] Steps and Structure: 1. Layered Preparation: The ultraviolet layer is prepared by cold pressing CeF3 into a thin sheet and sintering at high temperature for 1 hour. The visible light layer is prepared by Eu... 2+ :BAM and Ce 3+ YAG is mixed in a 4:6 ratio, cold-pressed, and then sintered at high temperature. The near-infrared layer uses Ti. 3+ 1. Al2O3 powder is ball-milled for 2 hours, cold-pressed into sheets, and then sintered at high temperature; 2. Stacked assembly: stacked in the order of ultraviolet → visible light → near-infrared light, and the whole is encapsulated in an aluminum alloy pressure ring shell; 3. High-efficiency heat dissipation: the base is set with microchannels and linked with thermoelectric cooler (TEC) to improve the heat dissipation effect and temperature stability of the fluorescent layer.

[0021] Performance characteristics: Full-band spectral accuracy fluctuation ≤2.8%.

[0022] Application scenario: Adapted to biomedical multispectral imaging systems. Attached Figure Description

[0023] Figure 1 : Schematic diagram of LED standard lamp structure (1. LED, 2. Aspherical quartz lens, 3. Fluorescent layer, 4. Heat dissipation module, 5. Large NA quartz lens).

[0024] Figure 2 Measured spectrum (240-1100 nm).

Claims

1. A standard intensity LED lamp, characterized in that... include: The structure includes an excitation module, a fluorescence conversion layer, an optical system, and a heat dissipation structure.

2. The excitation module as described in claim 1, characterized in that: It uses a 254nm ultraviolet LED chip, with an output power of 0.05-5W and a wavelength half-width at half maximum (WHM) of ≤30nm.

3. The fluorescence conversion layer as described in claim 1, characterized in that: The fluorescence conversion layer consists of a mixture of CeF3 and Eu. 2+ :BAM、Ce 3+ :YAG、Ti 3+ Composed of Al2O3, it is mixed by shaking or ball milling and then sandwiched into fluorescent ceramic sheets or sintered, with a thickness of 0.2-2mm.

4. The optical system as claimed in claim 1, characterized in that: The optical system includes an aspherical quartz lens group and uses symmetrical multi-channel LED focusing illumination to focus the output light to the central region of the phosphor layer, suppressing the uneven spot effect caused by the oblique incidence of the LED.

5. The heat dissipation structure as described in claim 1, characterized in that: A high thermal conductivity solid substrate is used in combination with an airflow channel for heat dissipation and cooling; the phosphor conversion layer is embedded in the center of the bottom of the heat dissipation structure, and the LEDs are symmetrically distributed on the inner wall of the heat dissipation device.

6. A method for calibrating a spectroscopic device, based on the standard lamp according to any one of claims 1-5, characterized by the following steps: Turn on the LED to excite the phosphor layer until the output is stable; introduce the continuous light output from the standard lamp into the spectral device to be calibrated through a spatial optical path or fiber optic coupling; turn on the spectral device to be calibrated to obtain the measured spectrum, compare it with the standard spectrum of the pre-calibrated LED standard intensity lamp, divide the measured spectrum by the standard spectrum data and normalize it to obtain the calibration curve of the spectral device, and then use the obtained calibration curve to calibrate the spectral device.

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