{"id":9614,"date":"2026-08-17T20:21:15","date_gmt":"2026-08-17T12:21:15","guid":{"rendered":"https:\/\/es.ledtestsystem.com\/?p=9614"},"modified":"2026-08-17T20:21:15","modified_gmt":"2026-08-17T12:21:15","slug":"um-guia-completo-sobre-como-medir-lumens-para-testes-precisos-de-emissao-de-luz","status":"publish","type":"post","link":"https:\/\/ledtestsystem.com\/pt\/blogs\/um-guia-completo-sobre-como-medir-lumens-para-testes-precisos-de-emissao-de-luz\/","title":{"rendered":"A Comprehensive Guide on How to Measure Lumens for Accurate Light Output Testing"},"content":{"rendered":"

A Comprehensive Guide on How to Measure Lumens for Accurate Light Output Testing<\/strong><\/p>\n

Introduction to Luminous Flux Metrology<\/strong><\/p>\n

The quantification of visible light output, expressed in lumens (lm), constitutes the fundamental parameter for characterizing artificial light sources. Unlike illuminance (lux), which describes light incident upon a surface, luminous flux represents the total amount of visible energy emitted by a source per unit time. Accurate lumen measurement is not merely a matter of catalog specification; it is a critical determinant for energy compliance, photobiological safety assessment, and application-specific design validation across a spectrum of industries, from aeronautical instrumentation to horticultural lighting. However, the measurement of total luminous flux is inherently susceptible to geometric, spectral, and thermal errors. This technical document delineates the methodologies\u2014ranging from goniophotometry to esfera de integra\u00e7\u00e3o<\/a> photometry\u2014and emphasizes the prevailing industry solution: the integration of a spectroradiometer with a large-aperture integrating sphere, specifically the LISUN<\/a> LPCE-2\/LPCE-3<\/strong> system.<\/p>\n

The Physical Principles Governing Luminous Flux Determination<\/strong><\/p>\n

Photometry is the science of measuring light as perceived by the human visual system. The conversion from radiometric watts to photometric lumens requires weighting the spectral power distribution (SPD) against the photopic luminous efficiency function, V(\u03bb). Mathematically, luminous flux (\u03a6v) is defined as:<\/p>\n

\u03a6v = Km \u222b \u03a6e(\u03bb) V(\u03bb) d\u03bb<\/p>\n

Where \u03a6e(\u03bb) is the spectral radiant flux, V(\u03bb) is the standard luminosity curve, and Km is the maximum luminous efficacy (683 lm\/W at 555 nm). This spectral weighting necessitates either a filtered photodetector (with a response approximating V(\u03bb)) or a full spectral analysis. While the filtered detector method is simpler, it suffers from spectral mismatch errors, particularly for narrow-band emitters like LEDs and laser diodes. Consequently, the spectroradiometric method has become the gold standard for high-accuracy measurement, as it captures the full SPD and allows for simultaneous calculation of chromaticity coordinates, CCT (Correlated Color Temperature), and CRI (Color Rendering Index) alongside lumen output.<\/p>\n

Primary Measurement Methodologies: Goniophotometry versus Integrating Spheres<\/strong><\/p>\n

Two distinct approaches dominate luminance flux measurement: goniophotometry and integrating sphere photometry.<\/p>\n

Goniophotometry<\/strong> involves mechanically rotating a detector around the light source to map its spatial intensity distribution. Integrating this distribution over the entire solid angle yields total flux. While exceptionally accurate for directional sources and providing critical spatial data, goniophotometers are costly, slow, and require large dark rooms (typically 25\u201330 meters). This method is indispensable for automotive headlamps and street lighting, yet impractical for high-throughput production line testing of LED modules.<\/p>\n

Esfera Integradora<\/a> Photometry<\/strong>, conversely, measures the total flux by collecting the source’s emission inside a hollow, highly reflective sphere. The sphere’s interior is coated with a diffuse, high-reflectance material (typically BaSO4 or PTFE), causing multiple reflections that result in a uniform illuminance at the sphere wall. A detector located at a baffled port measures this radiance, which is directly proportional to the total luminous flux. The primary advantages are speed, cost-efficiency, and independence from source geometry. However, the accuracy of this method is contingent upon comprehension and mitigation of self-absorption and spatial non-uniformity, which is where modern spectroradiometric integration excels.<\/p>\n

The LISUN LPCE-2\/LPCE-3 Integrating Sphere and Spectroradiometer System: Architecture and Function<\/strong><\/p>\n

O LISUN LPCE-2<\/strong> and its advanced derivative, the LPCE-3<\/strong>, represent the confluence of absolute photometry and spectral radiometry. The system comprises a high-reflectance integrating sphere (available in diameters from 0.3 m to 3.0 m, accommodating small SMD LEDs to large LED street lights) coupled with a high-resolution array spectroradiometer (MSR-3000 series). A key differentiator is the LPCE-3<\/strong>\u2019s inclusion of an innovative DC\/AC constant current power supply<\/strong> and a spectral stray light elimination algorithm<\/strong>.<\/p>\n

The measurement protocol deviates from traditional single-channel photometry. Inside the sphere, a probe collects light from the sphere wall via a cosine-corrected diffuser, transmitting it through an optical fiber (solarization-resistant) to the spectroradiometer. The MSR-3000 utilizes a back-illuminated CCD array detector with a spectral range of 350\u20131100 nm. The system calculates lumens via direct integration of the SPD. To maintain absolute accuracy, calibration is performed using a standard lamp calibrated against national standards. The LPCE-3<\/strong> specifically enhances this through its “Multi-Geometry Calibration Compensation”<\/strong>, which corrects for the differences in spatial distribution between the calibration source and the test source.<\/p>\n\n\n\n\n\n\n\n\n\n\n
System Parameter<\/th>\nLPCE-2 Specification<\/th>\nEspecifica\u00e7\u00e3o LPCE-3<\/th>\nIndustry Relevance<\/th>\n<\/tr>\n<\/thead>\n
Sphere Diameters<\/strong><\/td>\n0.3m, 0.5m, 1.0m, 1.65m, 2m, 3m<\/td>\n0.3m \u2013 3m (Customizable)<\/td>\nAllows testing for 0.2W SMD to 1000W Highbay<\/td>\n<\/tr>\n
Spectroradiometer Model<\/strong><\/td>\nMSP-3000 (or MSR-3000)<\/td>\nMSR-3100 (High-Speed)<\/td>\nFaster measurement cycles for production line<\/td>\n<\/tr>\n
Wavelength Resolution<\/strong><\/td>\n\u22640.2nm<\/td>\n\u22640.2nm<\/td>\nCritical for narrow-band Laser Phosphor Lighting<\/td>\n<\/tr>\n
Luminous Flux Range<\/strong><\/td>\n0.001 lm \u2013 2,000,000 lm<\/td>\n0.001 lm \u2013 2,000,000 lm<\/td>\nCovers automotive low-beam to marine searchlights<\/td>\n<\/tr>\n
Velocidade de medi\u00e7\u00e3o<\/strong><\/td>\n<5 seconds (Full spectrum)<\/td>\n<1 second (Scan mode)<\/td>\nEnables 100% QC inspection in LED Manufacturing<\/td>\n<\/tr>\n
Core Feature<\/strong><\/td>\nSpectral Analysis<\/td>\nSpectral Stray Light Compensation<\/strong><\/td>\nEliminates sphere wall reflectance spectral errors<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Spatial and Spectral Error Sources in Sphere Photometry and Their Mitigation<\/strong><\/p>\n

Even with a calibrated sphere, erroneous lumen values arise from three primary physical phenomena. First, Self-Absorption<\/strong>: The test source, its holder, and wiring absorb light within the sphere. Since the calibration lamp and test source have different geometric shapes and absorption coefficients, a systematic error is introduced if uncorrected. The LPCE-2\/3<\/strong> systems address this via the Auxiliary Lamp Method<\/strong>\u2014a built-in stabilized quartz halogen lamp mounted inside the sphere. By measuring the illuminance with the auxiliary lamp on, with and without the test source, a correction coefficient (\u03b1) is derived to mathematically eliminate self-absorption errors.<\/p>\n

Second, Spatial Non-uniformity<\/strong>: The luminance at the sphere wall is not perfectly isotropic if the source emits a highly directional beam (e.g., a spot light or an automotive reflector). The LPCE system employs a baffle system and a matte white screen placed inside the sphere to block direct illumination of the detector port. For the LPCE-3, an advanced algorithm compensates for “spectralon” reflectivity variations at different wavelengths.<\/p>\n

Third, Spectral Mismatch<\/strong>: A silicon photodiode with a V(\u03bb) filter has a spectral response that deviates from the standard curve. For a phosphor-converted white LED, this creates a 5\u201310% error in lumen reading. The spectroradiometer, however, measures the SPD with high wavelength accuracy. The LISUN LPCE-3<\/strong> uses a double-grating (in select MSR models) to suppress stray light, ensuring that wavelengths beyond 780 nm (IR) do not contaminate the visible band measurement, a common issue in high-CCT automotive HID lamps.<\/p>\n

Calibration Standards and Traceability: Ensuring Data Integrity<\/strong><\/p>\n

Accurate lumen measurement demands traceability to national metrology institutes (NMI). The LISUN LPCE-2\/3 calibration process adheres to the LM-79-19<\/strong> (IESNA) and CIE 84<\/strong> guidelines. The procedure involves:<\/p>\n

    \n
  1. Primary Standard<\/strong>: A NIST-traceable tungsten halogen lamp (e.g., SCL-1400 series) with known spectral irradiance.<\/li>\n
  2. Sphere Calibration<\/strong>: The standard lamp is mounted at the center of the sphere (for source measurement mode) or at the wall (for wall-mounted mode). A constant current supply (DC) powers the lamp, and the spectroradiometer records the background (dark current) and the standard signal.<\/li>\n
  3. Calibration Constants<\/strong>: The system calculates the calibration factor (K) based on the known lumens of the standard lamp and the measured spectral signal.<\/li>\n
  4. Verification<\/strong>: A set of secondary standard LEDs (Red, Green, Blue, White) are measured. The deviation must be <0.5% for lumen accuracy and <0.001 for chromaticity (\u0394u\u2019v\u2019) to pass internal verification.<\/li>\n<\/ol>\n

    For the Ind\u00fastria Fotovoltaica<\/strong>, this calibration is vital not for visible light, but for determining the spectral irradiance of solar simulators (classified as AM1.5G). Here, the LISUN system is used to measure the spectral mismatch of the lamp against the ASTM G173 reference spectrum, ensuring that the “lumens” (though spectral irradiance is the key metric) do not misleadingly indicate energy when testing solar cell responses.<\/p>\n

    Application-Specific Lumen Testing Protocols<\/strong><\/p>\n

    The utilization of the LPCE-2\/3 system varies significantly across industries, each imposing unique conditional constraints:<\/p>\n

    LED & OLED Manufacturing (Quality Control)<\/strong><\/p>\n

    In rapid production environments, lumen accuracy must be balanced with throughput. The LPCE-3<\/strong> with its high-speed MSR-3101 spectroradiometer enables binning<\/strong> (sorting LEDs by luminous flux and CCT) at a rate of up to 1,000 parts per hour. The system’s ability to handle both continuous (DC) and modulated (PWM) drive currents is critical, as PWM dimming alters the peak spectral power, potentially confusing traditional lux meters. The spectroradiometer integrates the true RMS power over time.<\/p>\n

    Automotive Lighting Testing (ECE R112 & R113)<\/strong><\/p>\n

    Automotive headlamps require luminous flux measurement, not<\/em> just peak intensity. The LPCE-2, equipped with a 2-meter sphere, is utilized to measure total flux of LED headlamps and high-intensity discharge (HID) lamps. A specific protocol involves pre-heating the lamp to 95% of its stable luminous flux, then measuring. The system calculates the “Quick Photometry” mode to track the flux stabilization over 60 seconds, identifying anomalies like early-life flux droop due to junction temperature rise\u2014a critical quality parameter for OEM suppliers.<\/p>\n

    Aerospace and Aviation Lighting (SAE AS8037)<\/strong><\/p>\n

    Aviation lamps (e.g., runway edge lights, torching beacons) require photometric colors and flux within strict FAA thresholds. Given the use of incandescent as well as LED sources, the LPCE-3\u2019s high sensitivity at low flux levels (down to 0.001 lm) allows for testing of micro-miniature indicator lamps used in cockpit displays. The system\u2019s ability to measure chromaticity shift during thermal cycling (from -40\u00b0C to +85\u00b0C) within the sphere, using a temperature-controlled external enclosure, ensures conformance to aviation standards.<\/p>\n

    Stage and Studio Lighting (Entertainment Technology)<\/strong><\/p>\n

    Theatrical fixtures utilizing high-power LEDs require a metric beyond raw lumens, such as TM-30 Rg\/Rf, which requires SPD data. The LISUN system provides this, but also validates the Lumen Maintenance<\/strong> (LM-80) of the LED package. During accelerated aging tests, the LPCE-2 measures the flux at each read point. Because the sphere is vented and thermally managed, the radiance heat from a 500W stage lamp does not damage the sphere coating\u2014a common failure point in cheaper polymer spheres.<\/p>\n

    Scientific Research and Optical Instrument R&D<\/strong><\/p>\n

    When characterizing a new phosphor material for medical lighting, researchers must measure quantum efficiency and total flux. The LPCE-2\u2019s integrating sphere can be configured for relative measurements (using the auxiliary lamp) or absolute measurements. The instrument allows calculation of luminous efficacy of radiation (LER) in lm\/W_optical. This is critical for Equipamentos de ilumina\u00e7\u00e3o m\u00e9dica<\/strong>, where the Correlated Color Temperature (CCT) must match surgical requirements (typically 4000K\u20135000K) and the luminance must be sufficient for deep cavity illumination\u2014yet not contribute to tissue phototoxicity. The spectral data ensures the UV\/A component (below 400 nm) is negligible, even if the total lumen count is high.<\/p>\n

    Marine and Navigation Lighting (IALA Recommendations)<\/strong><\/p>\n

    Marine lanterns often use LED clusters with complex optical lenses. The LPCE-2\/3 is used to verify that the luminous flux meets the “Nominal Night Range” specifications. Due to the low flux levels (e.g., 1 cd lanterns), the sphere must have high reflectivity and low noise. The LPCE-2 with a 0.3m sphere and a long integration time setting (up to 10 seconds) provides the necessary signal-to-noise ratio to measure dim sources accurately without interference from ambient electromagnetic noise.<\/p>\n

    Urban Lighting Design (ANSI\/IES TM-21)<\/strong><\/p>\n

    For street lighting manufacturers, lumen depreciation curves are essential. The LPCE-3<\/strong> facilitates the In-Situ Temperature Measurement (ISTMT) method: the lamp is run to equilibrium inside the sphere, and the case temperature is recorded. The spectroradiometer simultaneously calculates the flux. This data allows lighting designers to extrapolate the L70 (time to 70% lumen maintenance) using TM-21 extrapolation, which is legally binding in many state and federal procurement contracts.<\/p>\n

    Comparative Analysis: LISUN System vs. Conventional Photo-detectors<\/strong><\/p>\n

    Conventional integrating spheres using a lux meter or a photocell typically offer a luminous flux uncertainty of \u00b15% to \u00b18%. This magnitude of error is untenable for high-end production. The LISUN LPCE-2\/3 achieves an uncertainty of \u00b11.2% (k=2) for luminous flux and \u00b10.002 for chromaticity coordinates. The competitive advantage lies in the elimination of the need for multiple filters. A photodetector-based sphere must sequentially apply correction factors for different source types (e.g., HPS, Metal Halide, LED). The spectroradiometer is agnostic to source type; it measures the physics directly.<\/p>\n

    Furthermore, the LPCE-2<\/strong> has a specialized “remote control” software package that allows for data logging during stress tests, and the LPCE-3<\/strong> upgrades this with a PID temperature control<\/strong> interface for the sphere wall, minimizing thermal expansion of the sphere coating which can cause wavelength-dependent changes in reflectance. This level of detail is crucial for Pharmaceutical and Medical Lighting<\/strong> where sterilization processes generate heat.<\/p>\n

    Procedure for Accurate Lumen Measurement with the LPCE-2\/3<\/strong><\/p>\n

    To ensure valid results, operators must adhere to the following procedural sequence:<\/p>\n

      \n
    1. Preconditioning<\/strong>: The light source must be aged for at least 48 hours (for LEDs) to stabilize the phosphor and junction.<\/li>\n
    2. Sphere Cleanliness<\/strong>: Verify that the sphere interior reflectance (\u03c1) is >94%. Dust contamination severely skews spectral reflectance; use a soft brush and CO2 blower only.<\/li>\n
    3. Reference Standard Mount<\/strong>Para a geometria 4-pi (fonte no centro), certifique-se de que a l\u00e2mpada padr\u00e3o esteja posicionada no centro geom\u00e9trico. Para a geometria 2-pi (montagem na parede), a l\u00e2mpada deve estar alinhada com a parede da esfera.<\/li>\n
    4. Deslocamento escuro<\/strong>Cubra a esfera com um pano preto e registre o espectro escuro. Isso compensa o ru\u00eddo t\u00e9rmico do detector CCD.<\/li>\n
    5. Compensa\u00e7\u00e3o da l\u00e2mpada auxiliar<\/strong>Ligue a l\u00e2mpada auxiliar. Me\u00e7a o sinal sem a fonte de teste (I_aux1). Ligue a fonte de teste (com a auxiliar desligada). Me\u00e7a a fonte de teste. Desligue a fonte de teste, ligue a auxiliar novamente e me\u00e7a (I_aux2). O fluxo corrigido \u00e9 calculado como \u03a6_test = \u03a6_aux (I_test \/ I_aux1) <\/em> (I_aux2 \/ I_aux1) \u2013 corre\u00e7\u00e3o de absor\u00e7\u00e3o.<\/li>\n
    6. Integra\u00e7\u00e3o Espectral<\/strong>O software integra o SPD entre 380 nm e 780 nm. O filtro V(\u03bb) \u00e9 aplicado matematicamente. Certifique-se de que o intervalo de integra\u00e7\u00e3o corresponda \u00e0 condi\u00e7\u00e3o CIE (380-780 nm \u00e9 o padr\u00e3o, mas alguns padr\u00f5es industriais exigem 360-830 nm; o software LISUN permite intervalos definidos pelo usu\u00e1rio).<\/li>\n
    7. Aquecimento e estabiliza\u00e7\u00e3o<\/strong>O espectrorradi\u00f4metro deve ter a frequ\u00eancia da fonte de alimenta\u00e7\u00e3o travada. Ao medir fontes alimentadas por corrente alternada, utilize o \u201cModo de Medi\u00e7\u00e3o CA\u201d no software, que usa amostragem de alta frequ\u00eancia para evitar aliasing da rede el\u00e9trica de 50\/60 Hz.<\/li>\n<\/ol>\n

      Intera\u00e7\u00e3o entre cromaticidade e l\u00famen: dados al\u00e9m do fluxo<\/strong><\/p>\n

      Um aspecto crucial do sistema LISUN, frequentemente subutilizado na documenta\u00e7\u00e3o, \u00e9 sua capacidade de alinhar a emiss\u00e3o de l\u00famens com a cromaticidade em fun\u00e7\u00e3o da temperatura. Teste de equipamentos de exibi\u00e7\u00e3o<\/strong>, O ponto branco (D65) \u00e9 definido por coordenadas x,y espec\u00edficas. \u00c0 medida que o painel OLED envelhece, seu subpixel vermelho se degrada mais rapidamente que o azul, causando uma queda no fluxo luminoso total e uma altera\u00e7\u00e3o na cromaticidade. O LPCE-2\/3 pode varrer a tens\u00e3o de polariza\u00e7\u00e3o no dispositivo sob teste (DUT) enquanto monitora a distribui\u00e7\u00e3o espectral de pot\u00eancia (SPD). Isso permite que os engenheiros de P&D plotem o gr\u00e1fico de l\u00famen versus temperatura de cor correlacionada (CCT) versus tens\u00e3o em uma \u00fanica varredura, reduzindo o tempo de teste em 300%.<\/p>\n

      No Setor Fotovoltaico<\/strong>, Embora n\u00e3o me\u00e7a a "sa\u00edda de luz" para ilumina\u00e7\u00e3o, o sistema mede a Irradi\u00e2ncia Espectral<\/strong> do simulador solar. Os \u201cl\u00famens\u201d n\u00e3o s\u00e3o o objetivo; no entanto, a ampla faixa espectral do sistema (350-1100 nm) permite medir a discrep\u00e2ncia em rela\u00e7\u00e3o \u00e0 refer\u00eancia AM1.5G em seis bandas espectrais. O sistema calcula o fator de discrep\u00e2ncia espectral (MM), que indica ao operador se o simulador \u00e9 adequado para testes de sil\u00edcio monocristalino (que tem uma resposta r\u00e1pida \u00e0 luz infravermelha). Se a fonte de luz contiver infravermelho em excesso, a c\u00e9lula solar produzir\u00e1 uma corrente n\u00e3o representativa da luz solar real. O software do LPCE-2 calcula a \u2019Densidade de Fotocorrente\u201c (mA\/cm\u00b2) diretamente a partir dos dados espectrais, tornando-o uma ferramenta indispens\u00e1vel de P&D para a caracteriza\u00e7\u00e3o de c\u00e9lulas solares.<\/p>\n

      Verifica\u00e7\u00e3o e Correla\u00e7\u00e3o Interlaboratorial<\/strong><\/p>\n

      Para manter a objetividade, o sistema LISUN LPCE-2\/3 deve ser submetido a verifica\u00e7\u00f5es peri\u00f3dicas utilizando um LED padr\u00e3o em vez de apenas uma l\u00e2mpada de tungst\u00eanio. Como a l\u00e2mpada de tungst\u00eanio emite pico no infravermelho, a aus\u00eancia de luz azul pode mascarar erros de linearidade da esfera em 450 nm. Um LED azul padr\u00e3o deve ser comparado com a l\u00e2mpada calibrada pelo NIST. Devido \u00e0 redu\u00e7\u00e3o da luz esp\u00faria espectral no LPCE-3, a medi\u00e7\u00e3o de um LED azul de 450 nm com pot\u00eancia de pico de 100 mW n\u00e3o apresentar\u00e1 um pico em 500 nm (um artefato t\u00edpico em espectr\u00f4metros de baixo custo devido a efeitos de segunda ordem).<\/p>\n

      Gest\u00e3o de dados e registo de dados em tempo real<\/strong><\/p>\n

      Os testes de l\u00famen geram conjuntos de dados extensos. O pacote de software LISUN oferece um m\u00f3dulo de banco de dados que salva curvas de SPD, valores de l\u00famen e CCT para rastreamento de lotes<\/strong>. Para os fabricantes de autom\u00f3veis, isso fornece um "g\u00eameo digital" completo de cada unidade de farol, permitindo a rastreabilidade at\u00e9 o lote espec\u00edfico de pacotes de LED utilizados, verificando a conformidade com os padr\u00f5es. IATF 16949<\/strong> normas de gest\u00e3o da qualidade.<\/p>\n

      S\u00edntese T\u00e9cnica Conclusiva<\/strong><\/p>\n

      A medi\u00e7\u00e3o precisa de l\u00famens n\u00e3o \u00e9 uma simples opera\u00e7\u00e3o de detec\u00e7\u00e3o; trata-se de uma an\u00e1lise f\u00edsica rigorosa, condicionada por defini\u00e7\u00f5es fotom\u00e9tricas. Embora a goniofotometria forne\u00e7a resolu\u00e7\u00e3o espacial, a esfera integradora acoplada a um espectrorradi\u00f4metro de alta precis\u00e3o \u00e9 a \u00fanica solu\u00e7\u00e3o economicamente vi\u00e1vel que oferece fluxo total, al\u00e9m de cromaticidade, IRC e garantia espectral. O LISUN LPCE-2<\/strong> e LPCE-3<\/strong> representam o \u00e1pice dessa tecnologia, oferecendo baixa incerteza, alta velocidade e design robusto para ambientes de fabrica\u00e7\u00e3o severos. Seja gerando o relat\u00f3rio LM-80 para um novo filamento de LED para Ilumina\u00e7\u00e3o urbana<\/strong> ou garantindo que o farol de navega\u00e7\u00e3o emita exatamente 100 cd para Uso mar\u00edtimo<\/strong>, Esses sistemas fornecem os dados \u00f3pticos acion\u00e1veis necess\u00e1rios para certifica\u00e7\u00e3o e excel\u00eancia do produto.<\/p>\n

      Perguntas frequentes (FAQ)<\/strong><\/p>\n

      P1: Qual \u00e9 a diferen\u00e7a entre o LPCE-2 e o LPCE-3 em rela\u00e7\u00e3o \u00e0 corre\u00e7\u00e3o de luz difusa?<\/strong>
      \nA: O LPCE-3 apresenta uma entrada de fibra \u00f3ptica mais avan\u00e7ada e, opcionalmente, uma configura\u00e7\u00e3o de monocromador duplo na s\u00e9rie MSR-3100, que reduz a taxa de luz esp\u00faria para <0,01% (a definir) a 450 nm. Isso \u00e9 crucial ao medir um LED de banda estreita com alta pureza de cor, onde o pico azul pode inflar artificialmente a resposta vermelha do detector. O LPCE-2 utiliza software de corre\u00e7\u00e3o computacional, enquanto o LPCE-3 adiciona um bloqueio em n\u00edvel de hardware em janelas espectrais espec\u00edficas.<\/p>\n

      Q2: Esses sistemas conseguem medir o fluxo luminoso de uma lumin\u00e1ria de teto (como uma lumin\u00e1ria de embutir) sem a necessidade de uma sala escura?<\/strong>
      \nR: Sim. A esfera integradora n\u00e3o requer escurid\u00e3o ambiente, pois \u00e9 um sistema fechado. O \u00fanico requisito \u00e9 que a esfera esteja selada e que nenhuma luz externa penetre na jun\u00e7\u00e3o. Para lumin\u00e1rias de embutir grandes, utiliza-se o modo de transmiss\u00e3o para montagem na parede (geometria 2-pi), onde a luz \u00e9 montada na abertura de parede da esfera, direcionando todo o seu fluxo para dentro. A sala onde a esfera est\u00e1 localizada pode ter ilumina\u00e7\u00e3o padr\u00e3o.<\/p>\n

      P3: Como fa\u00e7o para medir um LED que est\u00e1 sendo dimerizado por PWM?<\/strong>
      \nA: O espectrorradi\u00f4metro do LPCE-2\/3 utiliza um princ\u00edpio de medi\u00e7\u00e3o por integra\u00e7\u00e3o (o CCD acumula f\u00f3tons ao longo do tempo). No entanto, para evitar aliasing com a frequ\u00eancia PWM, o software LISUN oferece um recurso de "Bloqueio de Frequ\u00eancia". Se a frequ\u00eancia PWM for de 5 kHz, o software define o tempo de integra\u00e7\u00e3o para 10 per\u00edodos consecutivos (2 ms no total) para calcular a m\u00e9dia do sinal \u00f3ptico corretamente. Al\u00e9m disso, recomenda-se o uso da fonte de corrente cont\u00ednua para polarizar o driver internamente, em vez de usar o dimmer PWM externo.<\/p>\n

      Q4: O sistema LISUN LPCE-2 \u00e9 v\u00e1lido para medir a resposta espectral absoluta de c\u00e9lulas fotovoltaicas?<\/strong>
      \nA: \u00c9 v\u00e1lido para medir o fonte de luz<\/em> O LPCE-2 \u00e9 usado no simulador solar, n\u00e3o para medir diretamente a resposta da c\u00e9lula. Para testar a resposta espectral de uma c\u00e9lula solar, \u00e9 necess\u00e1rio um monocromador e um detector para medir a corrente de curto-circuito da c\u00e9lula em comprimentos de onda espec\u00edficos. No entanto, o LPCE-2 \u00e9 usado para certificar que a l\u00e2mpada do simulador possui uma correspond\u00eancia espectral pr\u00f3xima (Classe ABA ou similar) ao AM1.5G, garantindo que a c\u00e9lula seja testada sob ilumina\u00e7\u00e3o em conformidade com os padr\u00f5es.<\/p>\n

      Q5: Qual o tamanho de esfera recomendado para um poste de ilumina\u00e7\u00e3o LED de 300W?<\/strong>
      \nA: O di\u00e2metro ideal \u00e9 determinado pela regra de que a dimens\u00e3o m\u00e1xima da fonte deve ser inferior a 1\/3 do di\u00e2metro da esfera. Uma lumin\u00e1ria de LED para ilumina\u00e7\u00e3o p\u00fablica de 300 W tem tipicamente entre 40 e 50 cm de largura. Portanto, uma esfera de 1,65 m \u00e9 a recomenda\u00e7\u00e3o m\u00ednima aceit\u00e1vel, sendo recomendada uma esfera de 2,0 m para lumin\u00e1rias com dissipadores de calor grandes. Isso impede que a fonte domine o campo de vis\u00e3o da esfera e garante que as m\u00faltiplas interreflex\u00f5es preservem a integra\u00e7\u00e3o Lambertiana.<\/p>","protected":false},"excerpt":{"rendered":"

      A Comprehensive Guide on How to Measure Lumens for Accurate Light Output Testing Introduction to Luminous Flux Metrology The quantification of visible light output, expressed in lumens (lm), constitutes the fundamental parameter for characterizing artificial light sources. Unlike illuminance (lux), which describes light incident upon a surface, luminous flux represents the total amount of visible […]<\/p>\n","protected":false},"author":1,"featured_media":3432,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[1057],"class_list":["post-9614","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blogs","tag-how-to-measure-lumens"],"_links":{"self":[{"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/posts\/9614","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/comments?post=9614"}],"version-history":[{"count":1,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/posts\/9614\/revisions"}],"predecessor-version":[{"id":9615,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/posts\/9614\/revisions\/9615"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/media\/3432"}],"wp:attachment":[{"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/media?parent=9614"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/categories?post=9614"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ledtestsystem.com\/pt\/wp-json\/wp\/v2\/tags?post=9614"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}