CN110068392A - A kind of luminous flux measurement device and method of LED light source - Google Patents

Abstract

The invention relates to photometric measurement technology, in particular to a luminous flux measurement device and method of an LED light source. The above-mentioned luminous flux measuring device includes: a hollow sphere with a diffuse reflection coating inside, and at least three mounting holes are provided on the spherical wall of the hollow sphere; a 2π standard light source is provided on the outside of the hollow sphere through the first mounting hole of the hollow sphere , the light-emitting surface of the 2π standard light source faces the interior of the hollow sphere; the measuring platform is used to place the LED light source to be measured, and the measuring platform is set outside the hollow sphere through the second mounting hole of the hollow sphere, and its light-emitting surface faces the interior of the hollow sphere; The illuminance detector is arranged outside the hollow sphere through the third installation hole of the hollow sphere, and the light incident surface of the illuminance detector is connected to the inside of the hollow sphere; and the spectral radiometer is connected to the illuminance detector through an optical fiber. The invention can accurately measure the luminous flux of different types of LED light sources, thereby fundamentally solving the problem of measuring the LED luminous flux.

Description

Device and method for measuring luminous flux of LED light source

technical field

The invention relates to photometric measurement technology, in particular to a luminous flux measurement device of an LED light source, and a luminous flux measurement method of an LED light source.

Background technique

Since the 1980s, semiconductor technology has developed rapidly, and LEDs have rapidly become a research hotspot as an emerging light source. Devices that use semiconductor PN junctions to convert electrical energy into light energy are called light-emitting diodes (LEDs). The LED device usually fixes its core semiconductor light-emitting chip on a conductive and thermally conductive metal bracket, and then encapsulates its periphery with epoxy resin, so as to concentrate light and protect the chip.

Luminous flux is the most important performance indicator of LED light sources. Existing methods for measuring the luminous flux of LED light sources mainly include a distribution photometer method and an integrating sphere photometer method.

The above-mentioned distribution photometer method uses a distributed photometer to measure the illuminance distribution reaching each point on the predetermined spherical surface, and then obtains the luminous flux of the light source by means of digital integration. The distributed photometer is an instrument used to measure the spatial distribution of the luminous intensity of the light source to be measured (that is, the illuminance on a predetermined spherical surface). Although the spectrophotometer method can accurately measure the luminous flux of the light source, the whole measurement process is cumbersome and time-consuming, and is easily affected by stray light, and there is also the problem of high cost of instruments and equipment.

The above integrating sphere photometer method uses an integrating sphere photometer to measure the illuminance values of the standard light source and the light source to be measured respectively, and then calculates the luminous flux of the light source to be measured according to the illuminance values. The ideal integrating sphere is a hollow sphere, and the inner wall of the sphere is uniformly coated with an ideal white diffuse reflection material. The diffuse illumination on the wall is proportional to the expected luminous flux of the light source received. Although the integrating sphere photometer method has fast measurement speed and simple operation, the standard light source required to be used must have similar power, structure, packaging, divergence angle and spectral power distribution to the light source to be measured, otherwise it will introduce a large measurement uncertainty.

In recent years, with the continuous development of the LED industry and the continuous improvement of the technical level, new LEDs for lighting emerge in an endless stream. Compared with traditional LEDs, new LEDs have higher power, more complex structures, and more diverse packaging forms.

Therefore, on the one hand, it is limited by the luminous characteristics of the narrow-band Gaussian distribution of the LED light source itself, and on the other hand, it is limited by the packaging forms of the new LED light source (single tube, SMD, TOP and COB, etc.) and the characteristics of various luminous colors. The standard LED light source to meet the comparison requirements of all LED light sources to be tested. The existing integrating sphere photometer method will inevitably introduce a large measurement uncertainty because it cannot find a standard light source that matches the LED light source to be measured.

In order to overcome the above-mentioned defects in the prior art, there is an urgent need in the art for a luminous flux measurement technology of LED light sources for accurately measuring the luminous flux of different types of LED light sources, thereby fundamentally solving the above-mentioned measurement problem of LED luminous flux.

SUMMARY OF THE INVENTION

A brief summary of one or more aspects is presented below to provide a basic understanding of the aspects. This summary is not an exhaustive overview of all contemplated aspects and is neither intended to identify key or critical elements of all aspects nor attempt to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.

In order to overcome the above-mentioned defects of the prior art, the present invention provides a luminous flux measuring device of an LED light source and a luminous flux measuring method of an LED light source, which are used to accurately measure the luminous flux of different types of LED light sources, thereby fundamentally solving the problem of The measurement problem of the above-mentioned LED luminous flux.

The luminous flux measuring device of the above-mentioned LED light source provided by the present invention includes:

a hollow sphere with a diffuse reflection coating inside, and at least three mounting holes are arranged on the spherical wall of the hollow sphere;

a 2π standard light source, which is arranged outside the hollow sphere through the first mounting hole of the hollow sphere, and the light-emitting surface of the 2π standard light source faces the interior of the hollow sphere;

a measuring platform for placing the LED light source to be measured, the measuring platform is arranged on the outside of the hollow sphere through the second mounting hole of the hollow sphere, and its light-emitting surface faces the inside of the hollow sphere;

an illuminance detector, disposed outside the hollow sphere through the third mounting hole of the hollow sphere, and the light incident surface of the illuminance detector is connected to the interior of the hollow sphere; and

A spectroradiometer is connected to the illuminance detector through an optical fiber.

Preferably, in the device for measuring the luminous flux of the LED light source provided by the present invention, the 2π standard light source may include:

a light homogenizer, located on the light-emitting surface of the 2π standard light source and connected to the first installation hole, the light homogenizer can be used to diffusely transmit the light emitted to the interior of the hollow sphere;

a tungsten halogen light source, located behind the diffuser, which can be used to emit full-spectrum radiation in the visible light band; and

The reflector is arranged behind the tungsten halogen light source and can be used to reflect all the light emitted by the tungsten halogen light source to the inside of the hollow sphere.

Preferably, in the device for measuring the luminous flux of the LED light source provided by the present invention, the light homogenizer may include a microlens array composed of a plurality of microlenses, and the plurality of microlenses may be oriented in a plurality of different directions to The radiation intensity of the outgoing light of the 2π standard light source is proportional to the cosine value of the outgoing angle.

Optionally, in the device for measuring the luminous flux of the LED light source provided by the present invention, the 2π standard light source may further include:

a lamp holder, which can be used to fix the tungsten halogen light source and connect a DC power source to supply power to the tungsten halogen light source; and

A radiator is arranged behind the reflector and is connected to the lamp holder. The radiator can be used to conduct the heat emitted by the halogen tungsten light source out of the 2π standard light source and dissipate it.

Optionally, in the device for measuring the luminous flux of the LED light source provided by the present invention, the measuring platform may include:

a temperature control sheet, which can be used to dissipate the heat emitted by the LED light source to be tested;

An insulating and heat-conducting layer, disposed above the temperature control sheet, can be used to place the LED light source to be tested and conduct the heat emitted by the LED light source to be tested to the temperature control sheet; and

The adjustable electrode is arranged above the temperature control sheet through the insulating sheet, and the position is adjustable in the horizontal direction, and the adjustable electrode can be used for electrically connecting the pins of the LED light source to be tested.

Preferably, in the device for measuring the luminous flux of the LED light source provided by the present invention, the measuring platform may further include:

A thermostat controller, connected to the temperature control sheet, can be used to adjust the temperature of the temperature control sheet to control the junction temperature of the LED light source to be measured to be constant.

Optionally, in the device for measuring the luminous flux of the LED light source provided by the present invention, the illuminance detector may include:

an adapter connecting the third mounting hole of the hollow sphere and the optical fiber; and

A radiation correction sheet, arranged on the light incident surface of the illuminance detector and connected to the incident end face of the optical fiber, the radiation correction sheet can be used to perform cosine correction and homogenization on the light radiation incident on the illuminance detector deal with.

Optionally, in the device for measuring the luminous flux of the LED light source provided by the present invention, the spectroradiometer may include:

a light guide device, connected to the exit end face of the optical fiber, which can be used to guide the optical radiation in the optical fiber into the spectroradiometer;

A monochromator, arranged at the rear end of the light guide device, can be used to separate the light radiation introduced by the light guide device into a plurality of monochromatic narrow-wave light radiation;

A detection module, located at the exit slit of the monochromator, can be used to detect the irradiance of the plurality of monochromatic narrow-wave optical radiations, and convert the irradiance of the plurality of monochromatic narrow-wave optical radiations is the corresponding digital signal; and

The signal processing module is communicatively connected to the detection module, and the signal processing module can be configured to calculate the luminous flux of the LED light source to be tested according to the irradiance of the plurality of monochromatic narrow-wave light radiations.

Preferably, in the device for measuring the luminous flux of the LED light source provided by the present invention, the signal processing module may be further configured to correct the nonlinear response of the spectroradiometer according to a linear correction method, and the linear correction method may include the steps of :

Use the calibrated spectral irradiance lamp to perform dimming in a large illuminance range, and measure a plurality of measured illuminance values with the spectral radiometer;

Determine the ideal response linear range of the spectroradiometer according to the measured illuminance value;

According to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the saturation response correction coefficient of the illuminance saturation part;

According to the measured illuminance value less than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the noise response correction coefficient of dark current and noise part; and

The nonlinear response of the illuminance saturation portion is corrected according to the saturation response correction coefficient, and the nonlinear responses of the dark current and noise portion are corrected according to the noise response correction coefficient.

Preferably, in the device for measuring the luminous flux of the LED light source provided by the present invention, the signal processing module may be further configured to:

applying least squares fitting to the plurality of measured illuminance values to obtain a linear equation for the plurality of measured illuminance values; and

The ideal response linear range of the spectroradiometer is determined according to the difference between the measured illuminance value and the recursive illuminance value of the linear equation.

Optionally, in the device for measuring the luminous flux of the LED light source provided by the present invention, it may further include:

The first baffle, which is arranged between the first installation hole and the third installation hole, can be used to prevent the light emitted by the 2π standard light source that is not diffusely reflected by the hollow sphere from directly entering the illumination detection the light-incident surface of the device; and

The second baffle, which is arranged between the second installation hole and the third installation hole, can be used to prevent the light emitted by the LED light source to be tested that is not diffusely reflected by the hollow sphere from directly entering the illuminance The light incident surface of the detector.

According to another aspect of the present invention, a method for measuring the luminous flux of an LED light source is also provided herein.

The method for measuring the luminous flux of the above-mentioned LED light source provided by the present invention comprises the steps of:

Use a 2π standard light source to calibrate the luminous flux measuring device of any of the above LED light sources;

Turn off the 2π standard light source, and make the LED light source to be tested emit light radiation into the hollow sphere;

Using an illuminance detector to obtain the light radiation diffusely reflected by the hollow sphere from the inside of the hollow sphere;

Obtaining the light radiation diffusely reflected by the hollow sphere from the illuminance detector using a spectroradiometer to measure spectral irradiance at the illuminance detector; and

The luminous flux of the LED light source is determined according to the spectral irradiance.

Preferably, in the method for measuring the luminous flux of the above-mentioned LED light source provided by the present invention, the calibration of the luminous flux measuring device of any of the above-mentioned LED light sources using a 2π standard light source may include the steps:

causing the 2π standard light source to emit full-spectrum radiation in the visible light band to the interior of the hollow sphere;

Using the illuminance detector to obtain the light radiation emitted by the 2π standard light source diffusely reflected by the hollow sphere from the inside of the hollow sphere;

Using a spectroradiometer to obtain the optical radiation emitted by the 2π standard light source from the illuminance detector to measure its spectral irradiance; and

The spectroradiometer is calibrated according to the known spectral irradiance of the 2π standard light source and the spectral irradiance measured by the spectroradiometer.

Preferably, in the method for measuring the luminous flux of the LED light source provided by the present invention, the step of causing the 2π standard light source to emit full-spectrum radiation in the visible light band to the interior of the hollow sphere may include the steps:

Powering the halogen tungsten light source in the 2π standard light source to generate full-spectrum radiation in the visible light band;

Using a reflector to reflect the light radiation generated by the tungsten halogen light source toward the interior of the hollow sphere to generate light radiation at a 2π space angle toward the interior of the hollow sphere; and

A diffuser is used to diffusely transmit the light radiation generated by the halogen tungsten light source and the light radiation reflected by the reflector, so that the radiation intensity of the outgoing light from the 2π standard light source is proportional to the cosine value of the outgoing angle. .

Optionally, in the method for measuring the luminous flux of the LED light source provided by the present invention, the measuring the spectral irradiance at the illuminance detector may include the steps:

using a monochromator to separate the light radiation diffusely reflected by the hollow sphere into a plurality of monochromatic narrow-wave light radiation; and

The illumination intensities of the plurality of monochromatic narrow-wave optical radiations are respectively measured to obtain the spectral irradiance at the illumination detector.

Optionally, in the method for measuring the luminous flux of the LED light source provided by the present invention, the measuring the spectral irradiance at the illuminance detector may further include the steps of:

Use the calibrated spectral irradiance lamp to perform dimming in a large illuminance range, and measure a plurality of measured illuminance values with the spectral radiometer;

Determine the ideal response linear range of the spectroradiometer according to the measured illuminance value;

According to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the saturation response correction coefficient of the illuminance saturation part;

According to the measured illuminance value less than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the noise response correction coefficient of dark current and noise part; and

The nonlinear response of the illuminance saturation portion is corrected according to the saturation response correction coefficient, and the nonlinear responses of the dark current and noise portion are corrected according to the noise response correction coefficient.

Preferably, in the method for measuring the luminous flux of the LED light source provided by the present invention, determining the ideal response linear range of the spectroradiometer according to the measured illuminance value may include the steps of:

Using least squares fitting to a plurality of measured illuminance values measured by the spectroradiometer to obtain a linear equation of the measured illuminance values; and

The ideal response linear range of the spectroradiometer is determined according to the difference between the measured illuminance value and the recursive illuminance value of the linear equation.

Optionally, in the method for measuring the luminous flux of the LED light source provided by the present invention, the determining the luminous flux of the LED light source according to the spectral irradiance may include the steps:

Integrating the spectral irradiance to obtain the illumination intensity at the illuminance detector;

The luminous flux of the LED light source is determined according to the light intensity at the illuminance detector and the area inside the hollow sphere.

Description of drawings

The above-described features and advantages of the present invention can be better understood after reading the detailed description of the embodiments of the present disclosure in conjunction with the following drawings. In the drawings, components are not necessarily drawn to scale and components with similar related characteristics or features may have the same or similar reference numbers.

FIG. 1 shows a schematic structural diagram of a device for measuring luminous flux of an LED light source according to an aspect of the present invention.

FIG. 2 shows a schematic structural diagram of a 2π standard light source provided according to an embodiment of the present invention.

FIG. 3 shows a schematic structural diagram of a measurement platform provided according to an embodiment of the present invention.

FIG. 4 shows a schematic structural diagram of an illumination detector provided according to an embodiment of the present invention.

FIG. 5 shows a schematic flowchart of a method for measuring luminous flux of an LED light source according to another aspect of the present invention.

FIG. 6 shows a schematic flowchart of a linearity correction method provided according to an embodiment of the present invention.

reference number

1 hollow sphere;

2 2π standard light source;

21 Diffuser;

22 reflectors;

23 halogen tungsten light source;

24 lamp holder;

25 radiator;

3 measuring platform;

31 LED chip to be tested;

32 aluminum substrate;

33 Insulation and heat conduction layer;

34 insulating sheet;

35 temperature control sheets;

36 LED chip pins;

37 adjustable electrodes;

4 illumination detector;

5 optical fibers;

6 Spectroradiometer;

7 first baffle;

8 second baffle;

501-505 The steps of the luminous flux measurement method of LED light source;

601-605 Steps of Linearity Correction Method.

Detailed ways

The embodiments of the present invention are described below by specific embodiments, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Although the description of the invention will be presented in conjunction with the preferred embodiment, this does not mean that the features of the invention are limited to this embodiment. On the contrary, the purpose of introducing the invention in conjunction with the embodiments is to cover other options or modifications that may be extended based on the claims of the invention. The following description will contain numerous specific details in order to provide a thorough understanding of the present invention. The invention may also be practiced without these details. Also, some specific details will be omitted from the description in order to avoid obscuring or obscuring the gist of the present invention.

In the description of the present invention, it should be noted that the terms "installed", "connected" and "connected" should be understood in a broad sense, unless otherwise expressly specified and limited, for example, it may be a fixed connection or a detachable connection Connection, or integral connection; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood in specific situations.

In addition, "top", "bottom", "left", "right", "top", "bottom", "horizontal", "vertical" used in the following description should be understood as the paragraph and related appendix The orientation shown in the figure. This relative term is only for convenience of description, and does not mean that the device described needs to be manufactured or operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

It will be understood that although the terms "first," "second," "third," etc. may be used herein to describe various components, regions, layers and/or sections, these components, regions, layers and/or sections These terms should not be limited and are only used to distinguish different components, regions, layers and/or sections. Thus, a first component, region, layer and/or section discussed below could be termed a second component, region, layer and/or section without departing from some embodiments of the present invention.

In order to overcome the above-mentioned defects in the prior art, the present invention provides an embodiment of a luminous flux measuring device of an LED light source and an embodiment of a luminous flux measuring method of an LED light source, which are used to accurately measure the luminous flux of different types of LED light sources. , so as to fundamentally solve the above-mentioned measurement problem of LED luminous flux.

Please refer to FIG. 1 , which shows a schematic structural diagram of a device for measuring luminous flux of an LED light source according to an aspect of the present invention.

As shown in FIG. 1 , the device for measuring the luminous flux of the LED light source provided in this embodiment may include: a hollow sphere 1 , a 2π standard light source 2 , a measurement platform 3 , an illumination detector 4 , and a spectral radiometer 6 .

In one embodiment, the above-mentioned hollow sphere 1 may be an integrating sphere. The integrating sphere 1 can be formed by splicing upper and lower hemispheres, and the inner wall of the hollow sphere can be uniformly coated with a white diffuse reflection material with a diffuse reflection coefficient close to 1. The above-mentioned white diffuse reflection materials include, but are not limited to, magnesium oxide, barium sulfate, and diffuse reflection coatings made of polytetrafluoroethylene.

In one embodiment, at least three mounting holes may be provided on the spherical wall of the integrating sphere hollow sphere 1, wherein the first mounting hole may be used for mounting the 2π standard light source 2; the second mounting hole may be used for mounting the measuring platform 3 ; The third installation hole can be used to install the illuminance detector 4 .

In a preferred solution of this embodiment, the contact surfaces of the 2π standard light source 2 , the measurement platform 3 , the illuminance detector 4 and the hollow sphere 1 can preferably be set to the same curved surface as the radian of the inner wall of the hollow sphere 1 , so as to prevent these contact surfaces Interfere with the measurement of the luminous flux of the 2π standard light source 2 or the LED to be tested.

In another preferred solution of this embodiment, the device for measuring the luminous flux of the LED light source may further include a first baffle 7 and a second baffle 8 . The first baffle 7 can be arranged between the first installation hole and the third installation hole to prevent the light emitted by the 2π standard light source 2 that is not diffusely reflected by the hollow sphere 1 from directly entering the light incident surface of the illuminance detector 4 . The second baffle plate 8 can be arranged between the second installation hole and the third installation hole to prevent the light emitted by the LED light source to be measured that is not diffusely reflected by the hollow sphere 1 from directly entering the light incident surface of the illuminance detector 4 .

By arranging the first baffle 7 and the second baffle 8, it can be further ensured that all light radiation incident on the illuminance detector 4 is uniform light radiation diffusely reflected by the hollow sphere 1, thereby ensuring that the light incident surface of the illuminance detector 4 receives The received diffuse light intensity is proportional to the expected luminous flux of the light source received, resulting in higher test accuracy.

In the luminous flux measuring device of the LED light source provided in this embodiment, the standard light source used for calibrating the luminous flux measuring device can be a traceable 2π standard light source 2. The 2π standard light source 2 refers to a standard light source with an irradiation space angle of 2π. That is, a standard light source that can only illuminate forward based on the plane where the light source is located. A traceable standard light source means that the spectral irradiance value of the standard light source in the visible light band (380nm-780nm) has been accurately calibrated, and the user can know the corresponding irradiance value of the standard light source according to any wavelength required.

As shown in FIG. 1 , in one embodiment, the 2π standard light source 2 can be disposed outside the hollow sphere 1 through the first mounting hole of the hollow sphere 1 , and the light-emitting surface of the 2π standard light source 2 can face the interior of the hollow sphere 1 , All the light radiation it emits is thus emitted into the interior of the hollow sphere 1 .

Compared with the existing integrating sphere photometer method in which the light source is placed at the center of the integrating sphere, the above-mentioned 2π standard light source 2 and its matching temperature control fixture provided in this embodiment do not need to be installed at the center of the integrating sphere 1, so it can be It is suitable for integrating spheres 1 of various sizes, and can also effectively avoid the damage of condensed water to the inner wall of integrating sphere 1 .

The device for measuring the luminous flux of the LED light source provided in this embodiment is not only easy to install, but also does not block the light radiation emitted by the 2π standard light source 2 and the LED light source to be measured. Therefore, a more uniform integrating sphere response can be obtained, thereby obtaining Higher test accuracy.

Please refer further to FIG. 2 , which shows a schematic structural diagram of a 2π standard light source provided according to an embodiment of the present invention.

As shown in FIG. 2 , in one embodiment, the 2π standard light source 2 may include a diffuser 21 , a reflector 22 , and a tungsten halogen light source 23 .

The above-mentioned light homogenizer 21 can be arranged at the front end of the 2π standard light source 2 , that is, the light-emitting surface of the 2π standard light source 2 , and is connected to the first installation hole. The light homogenizer 21 can be used to perform uniform diffuse transmission processing on the light emitted by the 2π standard light source 2 , so that the outgoing angle thereof is as large as possible, and the light is uniformly emitted into the hollow sphere 1 .

In a preferred solution of this embodiment, the light homogenizer 21 may preferably be designed as a microlens array composed of a plurality of microlenses. The plurality of microlenses in the microlens array can be oriented in different directions, so that the 2π standard light source 2 constitutes a Lambertian radiator. That is to say, after the diffuse transmission processing of the diffuser 21, the radiant intensity of the emitted light of the 2π standard light source 2 can be proportional to the cosine value of its emission angle, thereby further improving the uniformity of the emitted light and reducing the influence of the spatial response.

As shown in FIG. 2 , the above-mentioned halogen tungsten light source 23 can be arranged behind the light homogenizer 21 to provide the outgoing light of the 2π standard light source 2 . Since the halogen tungsten light source 23 can emit full-spectrum radiation in the visible light band (380nm-780nm), the halogen tungsten light source 23 can be used with a monochromator to generate narrow-wave light radiation of any wavelength, thereby simulating the light emission of any LED light source to be measured. characteristic.

Since the spectral power distribution of LEDs is a narrow-band Gaussian distribution, even if the peak wavelengths differ by only a few nanometers, it will result in a large difference in the spectral power distribution. Compared with the prior art solution that requires a large number of LED light sources with different packages, bandwidths, and colors as standard light sources, the above-mentioned halogen tungsten light source 23 provided in this embodiment can be used as a general standard light source to reduce measurement costs. Compared with the prior art scheme that uses LED light sources with similar packaging, bandwidth, and color as the standard light source, the above-mentioned simulation scheme of using the halogen tungsten light source 23 with the monochromator provided in this embodiment can also more accurately match the LED light source to be tested. peak wavelength to obtain higher test accuracy. Compared with the LED light source whose spectral power distribution is a narrow-band Gaussian distribution, the halogen tungsten light source 23 is easier to trace and easy to perform spectral calibration. Compared with an incandescent lamp that can also generate full-spectrum radiation in the visible light band, the halogen tungsten lamp light source 23 has a smaller volume, so that better integrating sphere uniformity can be obtained.

The above-mentioned reflector 22 can be disposed behind the halogen tungsten light source 23, and its reflective surface can be made of metal material. Through the preferred design corresponding to the specific position of the halogen tungsten light source 23 , the reflector 22 can collect as much backward light radiation emitted by the halogen tungsten light source 23 as possible, and reflect all the backward light radiation toward the diffuser 21 , and then shoot towards the interior of the hollow sphere 1 . Through this preferred design, the 2π standard light source 2 can generate ideal high-efficiency spectral radiation.

Since most of the LED light sources on the market only emit light in the forward 2π space, and there is no LED light source that emits light radiation backward, the above-mentioned structure of the reflector 22 can not only effectively improve the light efficiency of the 2π standard light source 2, but also It can better simulate the luminous characteristics of the LED light source to be tested, so as to obtain higher test accuracy.

As shown in FIG. 2 , in a preferred solution of this embodiment, the above-mentioned 2π standard light source 2 may further include a lamp holder 24 and a heat sink 25 .

The above-mentioned lamp holder 24 can be used to fix the halogen tungsten light source 23 and be connected to a DC power source to supply power to the halogen tungsten light source 23 . The use of DC power supply to supply power to the halogen tungsten light source 23 can effectively improve the radiation stability of the halogen tungsten light source 23, thereby further obtaining higher test accuracy.

The above-mentioned heat sink 24 can be disposed behind the reflector 22 and connected to the lamp holder 23 . The radiator 24 can be designed into a sheet-like structure, and by increasing the contact area between the metal material and the air, the radiant heat emitted by the halogen tungsten light source 23 can be quickly exported to the 2π standard light source 2 and dissipated.

As shown in FIG. 1 , in the device for measuring the luminous flux of the LED light source provided in this embodiment, the measuring platform 3 for placing the LED light source to be measured can be installed outside the hollow sphere 1 through the second mounting hole of the hollow sphere 1 . The light-emitting surface of the measuring platform 3 can face the interior of the hollow sphere 1 , so that all the light radiation emitted by the LED light source to be measured is emitted into the interior of the hollow sphere 1 .

Compared with the existing integrating sphere photometer method that needs to replace the standard light source and the light source to be measured, the above-mentioned measurement platform 3 provided in this embodiment can be installed on the spherical wall of the integrating sphere 1 together with the 2π standard light source 2, which is more convenient. Measure the luminous flux of the LED light source to be tested. When measuring the luminous flux of multiple different LED light sources to be measured, the measuring personnel does not need to repeatedly disassemble and assemble the standard light source, but only needs to remove the measuring platform 3 to replace the LED light source to be measured, and then proceed to the next LED light source to be measured. Measurement.

Please refer further to FIG. 3 , which shows a schematic structural diagram of a measurement platform provided according to an embodiment of the present invention.

As shown in FIG. 3 , in one embodiment, the measurement platform 3 may include an insulating and thermally conductive layer 33 , a temperature control sheet 35 and an adjustable electrode 37 .

Since the luminous characteristics of the LED light source are greatly affected by the temperature of the PN junction, it is necessary to perform constant temperature control on the LED chip during the measurement of the luminous flux. In one embodiment, the temperature control sheet 35 may simply be a metal copper heat sink, which is used to dissipate the heat emitted by the LED chip 31 to be tested, so as to ensure that the luminous characteristics of the LED chip 31 to be tested will not increase due to the junction temperature. change occurs. In another preferred solution, the measurement platform 3 may also preferably include a thermostat controller (not shown). The thermostat controller can be electrically connected to the temperature control sheet 35 , and adjust the temperature of the temperature control sheet 35 by adjusting the voltage and current applied to the temperature control sheet 35 , thereby controlling the junction temperature of the LED chip 31 to be tested to be constant.

In one embodiment, the above-mentioned insulating and heat-conducting layer 33 may be electrically insulating heat-conducting silica gel or heat-conducting silica sheet. The insulating and heat-conducting layer 33 can be disposed above the temperature control sheet 35 for placing the LED chip 31 to be tested, and to conduct the heat emitted by the LED chip 31 to be tested to the temperature control sheet 35 . Since the thermally conductive silica gel or the thermally conductive silicon sheet has good electrical insulation capability, the insulating and thermally conductive layer 33 can form a good electrical isolation between the pins 36 of the LED chip 31 to be tested and the temperature control sheet 35, thereby preventing the thermal conductivity of the temperature control sheet 35 from being damaged. The voltage and current affect the light-emitting characteristics of the LED chip 31 to be tested, and prevent the two adjustable electrodes 37 from short-circuiting through the conductive copper temperature control sheet 35 .

In one embodiment, the above-mentioned adjustable electrodes 37 may be two metal sliding sheets respectively disposed on both ends of the temperature control sheet 35 through insulating sheets 34 . One metal slide electrode can be connected to the positive pole of the external DC power supply, while the other metal slide electrode can be connected to the negative pole of the external DC power supply. The two metal slider adjustable electrodes 37 can be slid left and right in the horizontal direction to adjust their relative positions, so as to be electrically connected to the pins 36 of the LED chip 31 to be tested.

As shown in FIG. 3 , the LED chip 31 to be tested can be disposed on an aluminum substrate 32 which is integrally formed, and the two sides of the aluminum substrate 32 can be provided with pins 36 for supplying power to the LED chip 31 to be tested. The measurement personnel can use an external DC power supply to supply power to the LED chip 31 under test from pin 36 to make it emit light stably. In a preferred solution, the measuring personnel can also use an external pulse power supply to control the LED chip 31 to be tested to emit light at a specific frequency and pulse width through the pin 36 .

When measuring the luminous flux of different LED chips 31 to be tested, since different LED chips 31 to be tested may have different packaging structures and sizes, the measuring personnel can slide the adjustable electrodes 37 left and right to adjust their relative positions, so as to adapt to different sizes of LED chips 31 to be tested. Measure the installation requirements of the LED chip 31 .

In a preferred solution, the adjustable electrode 37 can also have a certain elasticity, so that the LED chip 31 to be tested is tightly pressed on the temperature control sheet 35, thereby ensuring good contact between the chip pin 36 and the adjustable electrode 37, And ensure that the thermostat controller accurately controls the temperature of the LED chip 31 to be tested. Experimental data shows that, in this embodiment, the temperature control accuracy of the LED chip 31 to be tested by the thermostat controller can reach ±0.1°C.

As shown in FIG. 1 , in the device for measuring the luminous flux of the LED light source provided in this embodiment, the illuminance detector 4 for detecting the average luminous intensity inside the integrating sphere 1 can be installed in the hollow through the third mounting hole of the hollow sphere 1 . Outside of sphere 1. The light incident surface of the illuminance detector 4 can be connected to the interior of the hollow sphere 1 , so as to obtain the light radiation diffusely reflected by the hollow sphere 1 from the inner wall of the hollow sphere 1 .

Please refer further to FIG. 4 , which shows a schematic structural diagram of an illuminance detector provided according to an embodiment of the present invention.

As shown in FIG. 4 , the illuminance detector 4 may include an adapter 41 and a radiation correction sheet 42 .

The above-mentioned adapter 41 can connect the third mounting hole of the hollow sphere 1 and the optical fiber 5 for transmitting the optical radiation for the spectroradiometer 6, for the close combination between the two, so as to prevent the optical radiation from the third mounting hole of the integrating sphere 1. leaks from the seam.

The radiation correction sheet 42 can be arranged on the light incident surface of the illuminance detector 4 and connected to the incident end surface of the optical fiber 5 . In one embodiment, the radiation correction sheet 42 can perform cosine correction processing and homogenization processing on the optical radiation incident on the illuminance detector 4, so as to obtain higher test accuracy.

The optical fiber 43 described above can be used as a signal transmission device for delivering optical radiation to the spectroradiometer 6 . The illuminance detector 4 can transmit the optical radiation signal collected by the adapter 41 to the spectroradiometer 6 through the optical fiber 5 for receiving and processing.

As shown in FIG. 1 , in the device for measuring the luminous flux of the LED light source provided in this embodiment, the spectroradiometer 6 for calculating the luminous flux of the LED light source to be measured can be connected to the illuminance detector 4 through an optical fiber 5 .

In one embodiment, the spectroradiometer 6 may include a light guide, a monochromator, a detection module, and a signal processing module.

The light guide device can be connected to the outgoing end face of the optical fiber 5 for guiding the optical radiation in the optical fiber 5 into the spectroradiometer 6 and projecting it on the entrance slit of the monochromator.

The monochromator can be installed at the rear end of the light guide device, and is used to separate the light radiation introduced by the light guide device into a plurality of monochromatic narrow-wave light radiation, so that the signal processing module can obtain the irradiance of the light radiation of different wavelengths, respectively. Thereby the spectral irradiance of the light radiation is obtained.

The detection module can be arranged at the exit slit of the monochromator, and is used to detect the irradiance of multiple monochromatic narrow-wave light radiations. The detection module can convert the irradiance of multiple monochromatic narrow-wave optical radiations into corresponding digital signals for acquisition by the signal processing module.

The signal processing module can be communicatively connected to the detection module, so as to obtain the spectral irradiance of the LED light source to be tested according to the irradiance of the plurality of monochromatic narrow-wave light radiations. The signal processing module may also be configured to calculate the corresponding luminous fluxes according to the irradiance of the plurality of monochromatic narrow-wave light radiations, and integrate these luminous fluxes to obtain the luminous fluxes of the LED light source to be tested.

According to another aspect of the present invention, an embodiment of a method for measuring luminous flux of an LED light source is also provided herein.

Please refer to FIG. 5 , which shows a schematic flowchart of a method for measuring luminous flux of an LED light source according to another aspect of the present invention.

As shown in FIG. 5 , the method for measuring the luminous flux of the LED light source provided in this embodiment may include the steps:

501: Use a 2π standard light source to calibrate the luminous flux measuring device of the LED light source provided by any one of the foregoing embodiments;

502: Turn off the 2π standard light source, and make the LED light source to be tested emit light radiation into the hollow sphere;

503: Use an illuminance detector to obtain the light radiation diffusely reflected by the hollow sphere from the inside of the hollow sphere;

504: Using a spectroradiometer to obtain the light radiation diffusely reflected by the hollow sphere from the illuminance detector to measure the spectral irradiance at the illuminance detector; and

505: Determine the luminous flux of the LED light source according to the spectral irradiance.

In one embodiment, when using the 2π standard light source to calibrate the luminous flux measuring device of the LED light source, the measuring personnel can now use the 2π standard light source to emit full-spectrum radiation in the visible light band (380nm-780nm) into the hollow sphere; The illuminance detector obtains the light radiation emitted by the 2π standard light source diffusely reflected by the hollow sphere from the inside of the hollow sphere; and then uses a spectral radiometer to obtain the light radiation emitted by the 2π standard light source from the illuminance detector to measure its spectral irradiance.

As mentioned above, since the standard light source of the luminous flux measurement device of the LED light source is a traceable 2π standard light source, its spectral irradiance value in the visible light band (380nm-780nm) has been accurately calibrated. The wavelength knows the irradiance value corresponding to the standard light source. Therefore, the surveyor can calibrate the spectroradiometer by comparing the spectral irradiance measured by the spectroradiometer with the spectral irradiance of a known 2π standard light source.

In other words, in a preferred solution of this embodiment, the measurement personnel can first supply DC power to the halogen tungsten light source in the 2π standard light source to generate stable full-spectrum radiation in the visible light band; The backward light radiation generated by the light source is all reflected to the interior of the hollow sphere to generate light radiation at a 2π space angle toward the interior of the hollow sphere; and preferably a diffuser is used for the light radiation generated by the halogen tungsten light source and reflected by the reflector. The light radiation is diffusely transmitted so that the 2π standard light source constitutes a Lambertian radiator. That is to say, the radiation intensity of the outgoing light of the 2π standard light source is proportional to the cosine value of the outgoing angle, thereby generating more uniform light radiation for higher test accuracy.

In one embodiment, when measuring the spectral irradiance at the illuminance detector, the measuring personnel can first use a monochromator to separate the light radiation diffusely reflected by the hollow sphere into multiple monochromatic narrow-wave light radiations; and then measure the light radiation respectively. The illumination intensity of multiple monochromatic narrow-wave optical radiations to obtain the spectral irradiance at the illuminance detector on the inner wall of the integrating sphere.

In a preferred solution of this embodiment, in order to further deduct the interference of the saturated nonlinear response, dark current and noise of the spectroradiometer, so as to obtain higher test accuracy, the signal processing module of the spectroradiometer can also be preferably configured with To correct the nonlinear response of the spectroradiometer according to the linear correction method.

Please refer further to FIG. 6, which shows a schematic flowchart of a linearity correction method according to an embodiment of the present invention.

As shown in Figure 6, the above-mentioned linear correction method may include the steps:

601: Use the calibrated spectral irradiance lamp for dimming in a large illuminance range, and measure multiple measured illuminance values with a spectral radiometer;

602: Determine the ideal response linear range of the spectroradiometer according to the measured illuminance value;

603: According to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the saturation response correction coefficient of the illuminance saturation part;

604: Determine the noise response correction coefficients of the dark current and noise parts according to the measured illuminance value smaller than the ideal response linear range and the recursive illuminance value of the ideal response linear range; and

605: Correct the nonlinear response of the illuminance saturation part according to the saturation response correction coefficient, and correct the nonlinear response of the dark current and the noise part according to the noise response correction coefficient.

Before measuring the luminous flux parameters of the LED light source to be measured, the measuring personnel can use a traceable high-precision photometric detector as a standard to calibrate the spectral irradiance lamp to obtain the spectral irradiance of the spectral irradiance lamp.

Those skilled in the art can understand that the above step of calibrating the spectral irradiance lamp is only a specific solution for obtaining the spectral irradiance of the spectral irradiance lamp, and is not used to limit the need to re-calibrate each time the above-mentioned linear correction method is executed. Spectral irradiance lamps. In the embodiment in which the spectral irradiance of the spectral irradiance lamp is known, the above step of calibrating the spectral irradiance lamp may also not be performed, but the ideal response linear range of the spectral radiometer can be directly determined according to the measured illuminance value.

In the process of measuring the luminous flux parameters of the LED light source to be measured, by dimming the spectral radiation illuminance lamp with a large illuminance range, the measurement personnel can obtain multiple measured values from the minimum illuminance range of the spectral radiometer to its maximum illuminance range. Illuminance value. By applying least squares fitting to these measured illuminance values, a linear equation of these measured illuminance values can be obtained. The surveyor can then determine the ideal response linear range of the spectroradiometer based on the difference between these measured illuminance values and the recursive illuminance value of the linear equation.

In one embodiment, the measurement personnel can define that if the difference between the measured illuminance value and the recursive illuminance value of the linear equation is not greater than 0.1% of the recursive illuminance value (ie, the linearity is greater than 99.9%), the measured illuminance value is determined. within the linear range of the ideal response of a spectroradiometer.

Those skilled in the art can understand that the above-mentioned criterion for judging that the linearity is greater than 99.9% is only a specific case provided in this embodiment, which is mainly used to clearly demonstrate the concept of the present invention and provide a specific solution that is convenient for the public to implement, It is not intended to limit the protection scope of the present invention. In other embodiments, according to the actual measurement accuracy requirements of the luminous flux of the LED light source, the measurement personnel can also set the criterion for the ideal response linear range to be lower as 99%, or higher as 99.99%, or even 99.999%.

After determining the ideal response linear range of the spectroradiometer, the measurement personnel can determine the irradiance larger than the ideal response linear range as the saturated part. Since the measured illuminance value of the saturated part will be saturated with the irradiance of the spectroradiometer, the error of the measured value will be small. The measurement personnel can determine the saturation of the illuminance saturated part according to the measured illuminance value and the recursive illuminance value of the ideal response linear range. The response correction coefficient is used to correct the measured illuminance value of the illuminance saturation part when actually measuring the LED light source to be measured.

Similarly, the measurement personnel can also determine the irradiance less than the linear range of the ideal response as the dark current and noise parts. Since the measured illuminance value of the dark current and noise part will have a small error in the measured value due to the dark current and noise of the spectroradiometer, the measurement personnel can determine the dark current according to the measured illuminance value and the recursive illuminance value of the ideal response linear range. The noise response correction coefficient of the current and noise parts is used to correct the measured illuminance value of the noise part when actually measuring the LED light source to be tested.

Those skilled in the art can understand that the linear calibration method described in the above-mentioned embodiment and completed manually by the measuring personnel can also be automatically executed by the signal processing module of the spectroradiometer according to the software installed therein. That is, the signal processing module of the spectroradiometer can be configured to automatically execute the linearity correction method provided by the above embodiments.

In a preferred solution, the signal processing module may be further configured to integrate the above-mentioned spectral irradiance to obtain the total illumination intensity at the illumination detector, and then according to the illumination intensity at the illumination detector and the interior of the hollow sphere Area to determine the luminous flux of the LED light source.

Although the above-described methods are illustrated and described as a series of acts for simplicity of explanation, it should be understood and appreciated that these methods are not limited by the order of the acts, as some acts may occur in a different order in accordance with one or more embodiments and/or occur concurrently with other actions from or not shown and described herein but understood by those skilled in the art.

The previous description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of the present disclosure. Thus, the present disclosure is not intended to be limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A luminous flux measuring device of an LED light source, characterized in that, comprising: a hollow sphere with a diffuse reflection coating inside, and at least three mounting holes are arranged on the spherical wall of the hollow sphere; a 2π standard light source, which is arranged outside the hollow sphere through the first mounting hole of the hollow sphere, and the light-emitting surface of the 2π standard light source faces the interior of the hollow sphere; a measuring platform for placing the LED light source to be measured, the measuring platform is arranged on the outside of the hollow sphere through the second mounting hole of the hollow sphere, and its light-emitting surface faces the inside of the hollow sphere; an illuminance detector, disposed outside the hollow sphere through the third mounting hole of the hollow sphere, and the light incident surface of the illuminance detector is connected to the interior of the hollow sphere; and A spectroradiometer is connected to the illuminance detector through an optical fiber. 2. The luminous flux measuring device of an LED light source according to claim 1, wherein the 2π standard light source comprises: The light homogenizer is arranged on the light-emitting surface of the 2π standard light source and is connected to the first installation hole. The radiation intensity of the outgoing light of the standard light source is proportional to the cosine of the outgoing angle; a tungsten halogen light source, arranged behind the diffuser, for emitting full-spectrum radiation in the visible light band; and The reflector is arranged behind the tungsten halogen light source, and is used for reflecting all the light emitted by the tungsten halogen light source to the inside of the hollow sphere. 3. The luminous flux measuring device of an LED light source according to claim 1, wherein the measuring platform comprises: a temperature control sheet, used to control the constant junction temperature of the LED light source to be tested; an insulating and heat-conducting layer, disposed above the temperature control sheet, for placing the LED light source to be tested and conducting the heat emitted by the LED light source to be tested to the temperature control sheet; and The adjustable electrode is arranged above the temperature control sheet through the insulating sheet, and the position is adjustable in the horizontal direction, and the adjustable electrode is used for electrically connecting the pins of the LED light source to be tested. 4. The luminous flux measuring device of an LED light source according to claim 1, wherein the illuminance detector comprises: an adapter connecting the third mounting hole of the hollow sphere and the optical fiber; and A radiation correction sheet, arranged on the light incident surface of the illuminance detector and connected to the incident end face of the optical fiber, the radiation correction sheet is used to perform cosine correction and homogenization processing on the optical radiation incident on the illuminance detector . 5. The luminous flux measuring device of an LED light source according to claim 1, wherein the spectroradiometer comprises: a light guide device, connected to the outgoing end face of the optical fiber, for guiding the optical radiation in the optical fiber into the spectroradiometer; A monochromator, arranged at the rear end of the light guide device, for separating the light radiation introduced by the light guide device into a plurality of monochromatic narrow-wave light radiation; A detection module, arranged at the exit slit of the monochromator, is used for detecting the irradiance of the plurality of monochromatic narrow-wave optical radiations, and converting the irradiance of the plurality of monochromatic narrow-wave optical radiations into the corresponding digital signal; and The signal processing module is communicatively connected to the detection module, and the signal processing module is configured to calculate the luminous flux of the LED light source to be tested according to the irradiance of the plurality of monochromatic narrow-wave light radiations. 6. A method for measuring the luminous flux of an LED light source, comprising: The luminous flux measuring device of the LED light source according to any one of claims 1-5 is calibrated by using a 2π standard light source; Turn off the 2π standard light source, and make the LED light source to be tested emit light radiation into the hollow sphere; Using an illuminance detector to obtain the light radiation diffusely reflected by the hollow sphere from the inside of the hollow sphere; Obtaining the light radiation diffusely reflected by the hollow sphere from the illuminance detector using a spectroradiometer to measure spectral irradiance at the illuminance detector; and The luminous flux of the LED light source is determined according to the spectral irradiance. 7. The method for measuring the luminous flux of an LED light source according to claim 6, wherein the calibrating the luminous flux measuring device of the LED light source according to any one of claims 1 to 5 using a 2π standard light source comprises: causing the 2π standard light source to emit full-spectrum radiation in the visible light band to the interior of the hollow sphere; Using the illuminance detector to obtain the light radiation emitted by the 2π standard light source diffusely reflected by the hollow sphere from the inside of the hollow sphere; Using a spectroradiometer to obtain the optical radiation emitted by the 2π standard light source from the illuminance detector to measure its spectral irradiance; and The spectroradiometer is calibrated according to the known spectral irradiance of the 2π standard light source and the spectral irradiance measured by the spectroradiometer. 8. The method for measuring the luminous flux of an LED light source according to claim 7, wherein the step of causing the 2π standard light source to emit full-spectrum radiation in the visible light band to the interior of the hollow sphere comprises: Powering the halogen tungsten light source in the 2π standard light source to generate full-spectrum radiation in the visible light band; Using a reflector to reflect the light radiation generated by the tungsten halogen light source toward the interior of the hollow sphere to generate light radiation at a 2π space angle toward the interior of the hollow sphere; and A diffuser is used to diffusely transmit the light radiation generated by the halogen tungsten light source and the light radiation reflected by the reflector, so that the radiation intensity of the outgoing light from the 2π standard light source is proportional to the cosine value of the outgoing angle. . 9. The method for measuring the luminous flux of an LED light source according to claim 6, wherein the measuring the spectral irradiance at the illuminance detector further comprises: Use the calibrated spectral irradiance lamp to perform dimming in a large illuminance range, and measure a plurality of measured illuminance values with the spectral radiometer; Determine the ideal response linear range of the spectroradiometer according to the measured illuminance value; According to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the saturation response correction coefficient of the illuminance saturation part; According to the measured illuminance value less than the ideal response linear range and the recursive illuminance value of the ideal response linear range, determine the noise response correction coefficient of the dark current and noise parts; and The nonlinear response of the illuminance saturation portion is corrected according to the saturation response correction coefficient, and the nonlinear response of the dark current and noise portion is corrected according to the noise response correction coefficient. 10. The method for measuring the luminous flux of an LED light source according to claim 9, wherein the determining the ideal response linear range of the spectroradiometer according to the measured illuminance value comprises: Using least squares fitting to a plurality of measured illuminance values measured by the spectroradiometer to obtain a linear equation of the measured illuminance values; and The ideal response linear range of the spectroradiometer is determined according to the difference between the measured illuminance value and the recursive illuminance value of the linear equation.