CN110068392B - Luminous flux measuring device and method for LED light source - Google Patents
Luminous flux measuring device and method for LED light source Download PDFInfo
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- CN110068392B CN110068392B CN201910422108.2A CN201910422108A CN110068392B CN 110068392 B CN110068392 B CN 110068392B CN 201910422108 A CN201910422108 A CN 201910422108A CN 110068392 B CN110068392 B CN 110068392B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
- G01J1/00—Photometry, e.g. photographic exposure meter
- G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
- G01J2001/4247—Photometry, e.g. photographic exposure meter using electric radiation detectors for testing lamps or other light sources
- G01J2001/4252—Photometry, e.g. photographic exposure meter using electric radiation detectors for testing lamps or other light sources for testing LED's
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Abstract
The invention relates to a photometric measurement technology, in particular to a luminous flux measurement device and method of an LED light source. The light flux measuring device includes: the hollow sphere is internally provided with a diffuse reflection coating, and the sphere wall of the hollow sphere is provided with at least three mounting holes; the 2 pi standard light source is arranged outside the hollow sphere through the first mounting hole of the hollow sphere, and the light emitting surface of the 2 pi standard light source faces the inside of the hollow sphere; the measuring platform is used for placing the LED light source to be measured, and is arranged outside the hollow sphere through the second mounting hole of the hollow sphere, and the light emitting surface of the measuring platform faces the inside of the hollow sphere; the illumination detector is arranged outside the hollow sphere through a third mounting hole of the hollow sphere, and the light incident surface of the illumination detector is connected with the inside of the hollow sphere; and a spectral radiometer connected to the illuminance detector by 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 luminous flux of the LEDs.
Description
Technical Field
The present invention relates to photometric measurement technologies, and in particular, to a device and a method for measuring luminous flux of an LED light source.
Background
Since the 80 s of the last century, semiconductor technology has been rapidly developed, and LEDs are rapidly becoming a research hotspot as an emerging light source. Devices that convert electrical energy into Light energy using a semiconductor PN junction are called Light-emitting diodes (LEDs). The LED device generally fixes the semiconductor light-emitting chip at the core of the LED device on an electric and heat conducting metal bracket, and encapsulates the periphery of the LED device by epoxy resin, thereby playing roles of condensing light and protecting the chip.
Luminous flux is the most important performance index of LED light sources. The existing measuring method of the luminous flux of the LED light source mainly comprises a distribution photometer method and an integrating sphere photometer method.
The distribution photometer method uses the distribution photometer to measure the illuminance distribution of each point on the appointed sphere, and then obtains the luminous flux of the light source by a digital integration mode. A distributed photometer is an instrument for measuring the spatial distribution of the luminous intensity (i.e., illuminance on a contracted spherical surface) of a light source to be measured. Although the distribution photometer method can accurately measure the luminous flux of the light source, the whole measurement process is tedious and time-consuming and is easily affected by stray light, and there is also a problem that the instrument and equipment are expensive.
The integrating sphere photometer method uses an integrating sphere photometer, and calculates the luminous flux of the light source to be measured according to the illuminance values of the standard light source and the light source to be measured respectively. The ideal integrating sphere is a hollow sphere, the inner wall of which is uniformly coated with ideal white diffuse reflecting material, and the diffuse illuminance on the wall is proportional to the luminous flux of the expected received light source. Although the integrating sphere photometer has high measurement speed and simple operation, the standard light source is required to have similar power, structure, package, divergence angle, spectral power distribution and the like as the light source to be measured, otherwise, larger measurement uncertainty is introduced.
In recent years, with the continuous development of the LED industry and the continuous improvement of the technical level, new LED layers for illumination are endless. Compared with the traditional LED, the novel LED has larger power, more complex structure and more various packaging forms.
Therefore, on one hand, the LED light source is limited by the light emitting characteristics of the narrow-band Gaussian distribution of the LED light source, on the other hand, the novel LED light source packaging form (single tube, patch, TOP, COB and the like) and the characteristics of various light emitting colors are limited, and the comparison requirement of all LED light sources to be tested is difficult to meet through a limited LED standard light source. The existing integrating sphere photometer method can introduce larger measurement uncertainty because a standard light source matched with an LED light source to be measured cannot be found.
In order to overcome the above-mentioned drawbacks of the prior art, there is a need in the art for a luminous flux measurement technique of an LED light source for accurately measuring luminous fluxes of different types of LED light sources, thereby fundamentally solving the above-mentioned problem of measuring the luminous fluxes of LEDs.
Disclosure of Invention
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor 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 defects in the prior art, the invention provides a luminous flux measuring device of an LED light source and a luminous flux measuring method of the LED light source, which are used for accurately measuring luminous fluxes of different types of LED light sources, so that the problem of measuring the luminous fluxes of the LEDs is fundamentally solved.
The luminous flux measuring device of the LED light source provided by the invention comprises:
the hollow sphere is internally provided with a diffuse reflection coating, and the sphere wall of the hollow sphere is provided with at least three mounting holes;
The light-emitting surface of the 2 pi standard light source faces to the inner part of the hollow sphere;
the measuring platform is used for placing an LED light source to be measured, and is arranged outside the hollow sphere through a second mounting hole of the hollow sphere, and the light emitting surface of the measuring platform faces the inside of the hollow sphere;
the illumination detector is arranged outside the hollow sphere through a third mounting hole of the hollow sphere, and the light incident surface of the illumination detector is connected with the inside of the hollow sphere; and
and the spectrum radiometer is connected with the illuminance detector through an optical fiber.
Preferably, in the light flux measuring device of an LED light source provided by the present invention, the 2pi standard light source may include:
the light homogenizing device is arranged on the light emitting surface of the 2 pi standard light source and is connected with the first mounting hole, and the light homogenizing device can be used for performing diffuse transmission treatment on light emitted to the interior of the hollow sphere;
the halogen tungsten lamp light source is arranged behind the light homogenizing device and can be used for emitting full-spectrum radiation of a visible light wave band; and
the reflecting cup is arranged behind the halogen tungsten lamp light source and can be used for reflecting all light emitted by the halogen tungsten lamp light source into the hollow sphere.
Preferably, in the light flux measuring device of an 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 face in a plurality of different directions, so that the radiation intensity of the outgoing light of the 2pi standard light source is proportional to the cosine value of the outgoing angle.
Optionally, in the light flux measuring device of an LED light source provided by the present invention, the 2pi standard light source may further include:
the lamp holder can be used for fixing the halogen tungsten lamp light source and is connected with a direct current power supply to supply power for the halogen tungsten lamp light source; and
the radiator is arranged at the rear of the reflecting cup and is connected with the lamp holder, and the radiator can be used for guiding out the heat emitted by the halogen tungsten lamp light source from the 2 pi standard light source and emitting the heat.
Optionally, in the light flux measurement device of an LED light source provided by the present invention, the measurement platform may include:
the temperature control sheet can be used for emitting heat emitted by the LED light source to be tested;
the insulating heat conduction layer is arranged above the temperature control sheet and can be used for placing the LED light source to be tested and conducting 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 is adjustable in position in the horizontal direction, and the adjustable electrode can be used for being electrically connected with the pin of the LED light source to be tested.
Preferably, in the light flux measurement device of an LED light source provided by the present invention, the measurement platform may further include:
and the constant temperature controller is connected with the temperature control sheet and can be used for adjusting the temperature of the temperature control sheet so as to control the junction temperature of the LED light source to be tested to be constant.
Optionally, in the light flux measurement device of an 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
the radiation correction piece is arranged on the light incident surface of the illuminance detector and is connected with the incident end surface of the optical fiber, and the radiation correction piece can be used for performing cosine correction and homogenization treatment on the light radiation incident to the illuminance detector.
Optionally, in the light flux measurement device of an LED light source provided by the present invention, the spectrum radiometer may include:
the light guide device is connected with the emergent end face of the optical fiber and can be used for guiding the optical radiation in the optical fiber into the spectrum radiometer;
The monochromator is arranged at the rear end of the light guide device and can be used for separating the light radiation guided by the light guide device into a plurality of monochromatic narrow-wave light radiation;
the detection module is arranged at the exit slit of the monochromator and can be used for detecting the radiation illuminance of the plurality of monochromatic narrow-wave light radiation and converting the radiation illuminance of the plurality of monochromatic narrow-wave light radiation into corresponding digital signals; and
the signal processing module is in communication connection with the detection module and can be configured to calculate the luminous flux of the LED light source to be detected according to the radiant illuminance of the plurality of monochromatic narrow-wave light radiations.
Preferably, in the light flux measuring device of an LED light source provided by the present invention, the signal processing module may be further configured to correct the nonlinear response of the spectrum radiometer according to a linear correction method, and the linear correction method may include the steps of:
performing large-illuminance range dimming by adopting a spectrum radiation illuminance lamp with calibration completed, and measuring a plurality of actually measured illuminance values by using the spectrum radiation meter;
determining an ideal response linear range of the spectral radiometer according to the measured illuminance value;
Determining a saturation response correction coefficient of an illuminance saturation portion according to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range;
determining a noise response correction factor for the dark current and noise portion based on the measured luminance value less than the ideal response linear range and the recursive luminance value of the ideal response linear range; and
and correcting the nonlinear response of the illuminance saturation portion according to the saturation response correction coefficient, and correcting the nonlinear responses of the dark current and the noise portion according to the noise response correction coefficient.
Preferably, in the light flux measurement device of an LED light source provided by the present invention, the signal processing module may be further configured to:
fitting the measured illuminance values by using a least square method to obtain a linear equation of the measured illuminance values; and
and determining an ideal response linear range of the spectrum radiometer according to the difference value between the measured illumination value and the recursive illumination value of the linear equation.
Optionally, in the light flux measuring device of an LED light source provided by the present invention, the light flux measuring device may further include:
the first baffle is arranged between the first mounting hole and the third mounting hole and can be used for preventing light emitted by the 2 pi standard light source which is not diffusely reflected by the hollow sphere from directly entering the light incident surface of the illuminance detector; and
The second baffle is arranged between the second mounting hole and the third mounting hole and can be used for preventing light emitted by the LED light source to be detected, which is not diffusely reflected by the hollow sphere, from directly entering the light incident surface of the illuminance detector.
According to another aspect of the present invention, there is also provided herein a method of measuring luminous flux of an LED light source.
The luminous flux measuring method of the LED light source provided by the invention comprises the following steps:
scaling the luminous flux measuring device of any one of the LED light sources by adopting a 2 pi standard light source;
turning off the 2 pi standard light source, and enabling the LED light source to be tested to emit light radiation into the hollow sphere;
acquiring light radiation diffusely reflected by the hollow sphere from the interior of the hollow sphere by adopting an illuminance detector;
obtaining the light radiation diffusely reflected by the hollow sphere from the illuminance detector with a spectral radiometer to measure spectral irradiance at the illuminance detector; and
and determining the luminous flux of the LED light source according to the spectral irradiance.
Preferably, in the method for measuring luminous flux of an LED light source provided by the present invention, the calibration of the luminous flux measuring device of any one of the LED light sources by using a 2pi standard light source may include the steps of:
The 2 pi standard light source emits full spectrum radiation of visible light wave band to the interior of the hollow sphere;
acquiring light radiation emitted by the 2 pi standard light source diffusely reflected by the hollow sphere from the interior of the hollow sphere by adopting the illuminance detector;
acquiring light radiation emitted by the 2 pi standard light source from the illuminance detector by adopting a spectrum radiometer so as to measure the spectrum irradiance thereof; and
the spectral radiometer is scaled according to the known spectral irradiance of the 2 pi standard light source and the spectral irradiance measured by the spectral radiometer.
Preferably, in the method for measuring luminous flux of an LED light source provided by the present invention, the step of making the 2pi standard light source emit full spectrum radiation of visible light band into the hollow sphere may include the steps of:
powering a tungsten halogen light source of said 2 pi standard light source to produce full spectrum radiation in the visible band;
reflecting light radiation generated by the halogen tungsten lamp source towards the inside of the hollow sphere by adopting a reflecting cup so as to generate light radiation of 2 pi space angles towards the inside of the hollow sphere; and
and performing diffuse transmission treatment on the light radiation generated by the halogen tungsten lamp light source and the light radiation reflected by the reflecting cup by adopting a light homogenizer so that the radiation intensity of the emergent light of the 2 pi standard light source is in direct proportion to the cosine value of the emergent angle.
Optionally, in the method for measuring luminous flux of an LED light source provided by the present invention, the measuring the spectral irradiance at the illuminance detector may include the steps of:
separating the light radiation diffusely reflected by the hollow sphere into a plurality of monochromatic narrow-wave light radiation by using a monochromator; and
the illumination intensities of the plurality of monochromatic narrow-wave optical radiation are measured separately to obtain a spectral irradiance at the illuminance detector.
Optionally, in the method for measuring luminous flux of an LED light source provided by the present invention, the measuring the spectral irradiance at the illuminance detector may further include the steps of:
performing large-illuminance range dimming by adopting a spectrum radiation illuminance lamp with calibration completed, and measuring a plurality of actually measured illuminance values by using the spectrum radiation meter;
determining an ideal response linear range of the spectral radiometer according to the measured illuminance value;
determining a saturation response correction coefficient of an illuminance saturation portion according to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range;
determining a noise response correction factor for the dark current and noise portion based on the measured luminance value less than the ideal response linear range and the recursive luminance value of the ideal response linear range; and
And correcting the nonlinear response of the illuminance saturation portion according to the saturation response correction coefficient, and correcting the nonlinear responses of the dark current and the noise portion according to the noise response correction coefficient.
Preferably, in the method for measuring luminous flux of an LED light source provided by the present invention, the determining the ideal response linear range of the spectral radiometer according to the measured illuminance value may include the steps of:
fitting a plurality of measured illuminance values measured by the spectrum radiometer by adopting a least square method so as to obtain a linear equation of the measured illuminance values; and
and determining an ideal response linear range of the spectrum radiometer according to the difference value between the measured illumination value and the recursive illumination value of the linear equation.
Optionally, in the method for measuring luminous flux of an 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 of:
integrating the spectral irradiance to obtain an illumination intensity at the illuminance detector;
and determining the luminous flux of the LED light source according to the illumination intensity at the illumination detector and the area inside the hollow sphere.
Drawings
The above features and advantages of the present invention will be better understood after reading the detailed description of embodiments of the present disclosure in conjunction with the following drawings. In the drawings, the components are not necessarily to scale and components having similar related features or characteristics may have the same or similar reference numerals.
Fig. 1 shows a schematic structure of a luminous flux measuring device of an LED light source according to an aspect of the present invention.
Fig. 2 shows a schematic structural diagram of a 2pi 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 invention.
Fig. 4 shows a schematic structure of an illuminance detector according to an embodiment of the present invention.
Fig. 5 shows a flow chart of a method for measuring luminous flux of an LED light source according to another aspect of the present invention.
Fig. 6 shows a flow diagram of a method for linearity correction provided according to an embodiment of the present invention.
Reference numerals
1. A hollow sphere;
22 pi standard light source;
21. a light homogenizer;
22. a reflective cup;
23. A halogen tungsten lamp light source;
24. a lampholder;
25. a heat sink;
3. a measurement platform;
31. an LED chip to be tested;
32. an aluminum substrate;
33. an insulating heat conducting layer;
34. an insulating sheet;
35. a temperature control sheet;
36 LED chip pins;
37. an adjustable electrode;
4. an illuminance detector;
5. an optical fiber;
6. a spectral radiometer;
7. a first baffle;
8. a second baffle;
the method for measuring the luminous flux of the 501-505 LED light source comprises the following steps of;
601-605 steps of the linearity correction method.
Detailed Description
Further advantages and effects of the present invention will become apparent to those skilled in the art from the disclosure of the present specification, by describing the embodiments of the present invention with specific examples. While the description of the invention will be presented in connection with a preferred embodiment, it is not intended to limit the inventive features to that embodiment. Rather, the purpose of the invention described in connection with the embodiments is to cover other alternatives or modifications, which may be extended by the claims based on the invention. The following description contains many specific details for the purpose of providing a thorough understanding of the present invention. The invention may be practiced without these specific details. Furthermore, some specific details are omitted from the description in order to avoid obscuring the invention.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In addition, the terms "upper", "lower", "left", "right", "top", "bottom", "horizontal", "vertical" as used in the following description should be understood as referring to the orientation depicted in this paragraph and the associated drawings. This relative terminology is for convenience only and is not intended to be limiting of the invention as it is described in terms of the apparatus being manufactured or operated in a particular orientation.
It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various elements, regions, layers and/or sections, these elements, regions, layers and/or sections should not be limited by these terms and these terms are merely used to distinguish between different elements, regions, layers and/or sections. Accordingly, 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 drawbacks of 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 for accurately measuring luminous fluxes of different types of LED light sources, thereby fundamentally solving the above-mentioned problem of measuring luminous fluxes of LEDs.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating a structure of a light flux measuring device of an LED light source according to an aspect of the present invention.
As shown in fig. 1, the light flux measuring device of the LED light source provided in this embodiment may include: a hollow sphere 1, a 2pi standard light source 2, a measurement platform 3, an illuminance detector 4, and a spectroradiometer 6.
In one embodiment, the hollow sphere 1 may be an integrating sphere. The integrating sphere 1 can be formed by splicing an upper hemisphere and a lower hemisphere, 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 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 can be formed on the wall of the hollow sphere 1 of the integrating sphere, wherein the first mounting hole can be used for mounting the 2pi standard light source 2; the second mounting hole may be used for mounting the measurement platform 3; a third mounting hole may be used for mounting the illuminance detector 4.
In a preferred embodiment of the present embodiment, the contact surfaces of the 2pi standard light source 2, the measuring platform 3, the illuminance detector 4 and the hollow sphere 1 may be preferably set to be a curved surface identical to the radian of the inner wall of the hollow sphere 1, so as to prevent the contact surfaces from interfering with the luminous flux of the measuring 2pi standard light source 2 or the LED to be measured.
In another preferred aspect of the present embodiment, the apparatus for measuring luminous flux of an LED light source may further include a first baffle 7 and a second baffle 8. The first baffle 7 may be disposed between the first mounting hole and the third mounting hole, and is used for preventing light emitted by the 2pi 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 8 may be disposed between the second mounting hole and the third mounting hole, and is used for preventing light emitted by the LED light source to be tested, which 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 the light radiation incident on the illuminance detector 4 is uniform light radiation diffusely reflected by the hollow sphere 1, so that the diffuse illumination intensity received by the light incident surface of the illuminance detector 4 is ensured to be in direct proportion to the luminous flux of the light source expected to be received, and further higher testing precision is obtained.
In the light flux measuring device of the LED light source provided in this embodiment, the standard light source used for calibrating the light flux measuring device may be a traceable 2pi standard light source 2. The 2 pi standard light source 2 refers to a standard light source with an irradiation space angle of 2 pi, namely a standard light source which can only irradiate forward based on the plane of the light source. The traceable standard light source means that the spectral illuminance value of the standard light source in the visible light band (380 nm-780 nm) is accurately calibrated, and a user can know the corresponding illuminance value of the standard light source according to any required wavelength.
As shown in fig. 1, in one embodiment, the 2pi standard light source 2 may be disposed outside the hollow sphere 1 through the first mounting hole of the hollow sphere 1, and the light emitting surface of the 2pi standard light source 2 may be directed toward the inside of the hollow sphere 1, so that all light radiation emitted therefrom is emitted to the inside of the hollow sphere 1.
Compared with the existing integrating sphere photometer method of placing the light source at the sphere center of the integrating sphere, the 2 pi standard light source 2 and the temperature control clamp matched with the same provided by the embodiment do not need to be arranged at the sphere center of the integrating sphere 1, so that the method can be applied to integrating spheres 1 with various sizes, and meanwhile damage of condensed water to the inner wall of the integrating sphere 1 can be effectively avoided.
The luminous flux measuring device of the LED light source is convenient to install, and does not shade light radiation emitted by the 2 pi standard light source 2 and the LED light source to be measured, so that more uniform integrating sphere response can be obtained, and higher test precision can be obtained.
Referring further to fig. 2, fig. 2 is a schematic diagram illustrating a 2 pi standard light source according to an embodiment of the present invention.
As shown in fig. 2, in one embodiment, the 2pi standard light source 2 may include a light homogenizer 21, a reflector cup 22, and a tungsten halogen light source 23.
The light homogenizer 21 may be disposed at the forefront end of the 2pi standard light source 2, that is, the light emitting surface of the 2pi standard light source 2, and connected to the first mounting hole. The light homogenizer 21 can be used for homogenizing and diffuse transmission of the light emitted by the 2pi standard light source 2 so that the emergent angle of the light is as large as possible and the light is uniformly emitted into the hollow sphere 1.
In a preferred version 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 may be oriented in a plurality of different directions, respectively, such that the 2pi standard light source 2 constitutes a lambertian radiator. That is, the radiation intensity of the light emitted from the 2pi standard light source 2 may be proportional to the cosine of the emission angle thereof through the diffuse transmission process of the light homogenizer 21, thereby further improving the uniformity of the light emitted therefrom to reduce the influence of the spatial response.
As shown in fig. 2, the tungsten halogen lamp light source 23 may be disposed behind the light homogenizer 21, for providing the outgoing light of the 2pi standard light source 2. The halogen tungsten lamp light source 23 can emit full spectrum radiation of visible light wave band (380 nm-780 nm), so the halogen tungsten lamp light source 23 can be matched with a monochromator to generate narrow wave light radiation of any wavelength, thereby simulating the luminous characteristic of any LED light source to be tested.
Since the spectral power distribution of an LED is a narrow-band gaussian distribution, even if peak wavelengths differ by only a few nanometers, a large difference in spectral power distribution results. Compared with the scheme that a large number of LED light sources with different packages, bandwidths and colors need to be prepared as standard light sources in the prior art, the halogen tungsten lamp light source 23 provided by the embodiment can be used as a general standard light source to reduce the measurement cost. Compared with the scheme that the LED light sources with similar package, bandwidth and color are adopted as the standard light sources in the prior art, the simulation scheme that the halogen tungsten light source 23 is matched with the monochromator can also be used for more accurately matching the peak wavelength of the LED light source to be tested, so that higher testing precision is obtained. The tungsten halogen light source 23 is easier to trace and is easier to spectrally calibrate than an LED light source with a narrow-band gaussian distribution of spectral power. The tungsten halogen light source 23 has a smaller volume than an incandescent lamp that is also capable of producing full spectrum radiation in the visible band, and thus better integrating sphere uniformity can be achieved.
The reflector cup 22 may be disposed behind the halogen tungsten light source 23, and the reflecting surface may be made of a metal material. By a preferred design corresponding to the specific location of the tungsten halogen lamp source 23, the reflector cup 22 collects as much of the rearward light radiation emitted by the tungsten halogen lamp source 23 as possible and reflects all of this rearward light radiation toward the light homogenizer 21 and thus toward the interior of the hollow sphere 1. With this preferred design, a 2 pi standard light source 2 can produce the desired high-efficiency spectral radiation.
Since most of the LED light sources in the market only emit light in the forward 2 pi space, but no LED light source emits light radiation in the backward direction, the structure of the reflective cup 22 not only can effectively improve the light efficiency of the 2 pi standard light source 2, but also can better simulate the light emitting characteristics of the LED light source to be tested, thereby obtaining higher test precision.
As shown in fig. 2, in a preferred embodiment of the present embodiment, the 2pi standard light source 2 may further include a lampholder 24 and a heat sink 25.
The lampholder 24 may be used to hold a tungsten halogen lamp source 23 and is connected to a dc power source to power the tungsten halogen lamp source 23. The direct current power supply mode is adopted to supply power to the halogen tungsten lamp light source 23, so that the radiation stability of the halogen tungsten lamp light source 23 can be effectively improved, and further higher testing precision is obtained.
The heat sink 24 may be disposed behind the reflector cup 22 and connected to the lampholder 23. The radiator 24 can be designed into a sheet-shaped structure, and the purpose of rapidly leading out and radiating the radiation heat emitted by the halogen tungsten lamp light source 23 from the 2 pi standard light source 2 is achieved by a method of increasing the contact area of the metal material and the air.
As shown in fig. 1, in the light flux measuring device of an LED light source provided in this embodiment, a measuring platform 3 for placing an LED light source to be measured may be disposed outside the hollow sphere 1 through a second mounting hole of the hollow sphere 1. The light emitting surface of the measuring platform 3 may face the inside of the hollow sphere 1, so that all light radiation emitted by the LED light source to be measured is emitted to the inside of the hollow sphere 1.
Compared with the existing integrating sphere photometry method requiring replacement of the standard light source and the light source to be measured, the measuring platform 3 provided by the embodiment can be installed on the sphere wall of the integrating sphere 1 together with the 2 pi standard light source 2, so that the luminous flux of the LED light source to be measured can be measured more conveniently. When measuring the luminous flux of a plurality of different LED light sources to be measured, a measurer does not need to repeatedly disassemble and assemble the standard light sources, but only needs to disassemble the measuring platform 3 to replace the LED light sources to be measured, and can continue the measurement of the next LED light source to be measured.
Referring further to fig. 3, fig. 3 is a schematic structural diagram of a measurement platform according to an embodiment of the present invention.
As shown in fig. 3, in one embodiment, the measurement platform 3 may include an insulating thermally conductive layer 33, a temperature control sheet 35, and an adjustable electrode 37.
Since the light emission characteristics of the LED light source are greatly affected by the PN junction temperature, 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 be a metallic copper heat sink for dissipating heat emitted by the LED chip 31 to be tested, so as to ensure that the light emitting characteristics of the LED chip 31 to be tested are not changed due to the rise of the junction temperature. In yet another preferred embodiment, the measuring platform 3 may also preferably comprise a thermostatic control (not shown). The constant temperature controller can be electrically connected with the temperature control sheet 35, and the temperature of the temperature control sheet 35 is adjusted by adjusting the voltage and the current applied to the temperature control sheet 35, so as to control the junction temperature of the LED chip 31 to be tested to be constant.
In one embodiment, the insulating and heat conducting layer 33 may be electrically insulating and heat conducting silica gel or heat conducting silicon wafer. The insulating heat conducting layer 33 may be disposed above the temperature control sheet 35, and is used for placing the LED chip 31 to be tested and conducting the heat emitted by the LED chip 31 to be tested to the temperature control sheet 35. Because the thermally conductive silica gel or the thermally conductive silicon wafer has good electrical insulation capability, the insulating thermally conductive layer 33 can form good electrical isolation between the pins 36 of the LED chip 31 to be tested and the temperature control sheet 35, so that the voltage and the current on the temperature control sheet 35 are prevented from affecting the light emitting characteristics of the LED chip 31 to be tested, and the two adjustable electrodes 37 are prevented from being short-circuited through the electrically conductive copper temperature control sheet 35.
In one embodiment, the adjustable electrode 37 may be two metal sliding sheets respectively disposed at two ends of the temperature control sheet 35 through the insulating sheet 34. One metal sliding vane electrode can be connected with the positive electrode of the external direct current power supply, and the other metal sliding vane electrode can be connected with the negative electrode of the external direct current power supply. The two metal slide adjustable electrodes 37 can slide left and right in the horizontal direction to adjust their relative positions, so as to be used for electrically connecting the pins 36 of the LED chip 31 to be tested.
As shown in fig. 3, the LED chip 31 to be tested may be disposed on an integrally formed aluminum substrate 32, and two sides of the aluminum substrate 32 may be provided with pins 36 for supplying power to the LED chip 31 to be tested. The measurer can use an external direct current power supply to supply power to the LED chip 31 to be measured from the pin 36 so as to enable the LED chip to emit light stably. In a preferred embodiment, the measurer can also use an external pulse power supply to control the LED chip 31 to be measured 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 measured, since different LED chips 31 to be measured may have different package structures and sizes, a measurer can slide the adjustable electrode 37 left and right to adjust the relative positions thereof, so as to adapt to the installation requirements of the LED chips 31 to be measured with different sizes.
In a preferred embodiment, the adjustable electrode 37 may also have a certain elasticity, so that the LED chip 31 to be tested is tightly pressed against the temperature control plate 35, thereby ensuring good contact between the chip pins 36 and the adjustable electrode 37, and ensuring accurate constant temperature control of the LED chip 31 to be tested by the constant temperature controller. Experimental data shows that in this embodiment, the temperature control accuracy of the thermostat controller to the LED chip 31 to be tested can reach ±0.1 ℃.
As shown in fig. 1, in the light flux measuring device of the LED light source provided in the present embodiment, the illuminance detector 4 for detecting the average illuminance inside the integrating sphere 1 may be disposed outside the hollow sphere 1 through the third mounting hole of the hollow sphere 1. The light incident surface of the illuminance detector 4 may be connected to the inside of the hollow sphere 1, thereby acquiring light radiation diffusely reflected by the hollow sphere 1 from the inner wall of the hollow sphere 1.
Referring further to fig. 4, fig. 4 is a schematic structural diagram of an illuminance detector 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 plate 42.
The adapter 41 may connect the third mounting hole of the hollow sphere 1 and the optical fiber 5 for transmitting optical radiation to the spectroradiometer 6 for tight coupling therebetween to prevent the optical radiation from leaking out from the joint of the third mounting hole of the integrating sphere 1.
The radiation correction sheet 42 may be provided 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 modifying sheet 42 may perform cosine modification and homogenization on the optical radiation incident on the illuminance detector 4, thereby achieving higher test accuracy.
The optical fiber 43 described above may be used as a signal transmission device for transmitting optical radiation to the spectroradiometer 6. The illuminance detector 4 may transmit the optical radiation signal collected by the adapter 41 to the spectroradiometer 6 through the optical fiber 5 for reception and processing.
As shown in fig. 1, in the above-described light flux measuring device of an LED light source provided in the present embodiment, a spectroradiometer 6 for calculating the light flux of the LED light source to be measured may be connected to an illuminance detector 4 through an optical fiber 5.
In one embodiment, the spectral radiometer 6 may include a light guide, a monochromator, a detection module, and a signal processing module.
The light guide may be connected to the exit end face of the optical fiber 5 for guiding the optical radiation in the optical fiber 5 to the spectroradiometer 6 and onto the entrance slit of the monochromator.
The monochromator can be arranged at the rear end of the light guide device and is used for separating the light radiation guided by the light guide device into a plurality of monochromatic narrow-wave light radiation so as to enable the signal processing module to respectively acquire the radiation illuminance of the light radiation with different wavelengths, thereby acquiring the spectrum radiation illuminance of the light radiation.
The detection module can be arranged at an exit slit of the monochromator and is used for detecting the illuminance of a plurality of monochromatic narrow-wave light radiations. The detection module can convert the radiation illumination of a plurality of monochromatic narrow-wave light radiation into corresponding digital signals for the signal processing module to acquire.
The signal processing module can be in communication connection with the detection module, so that the spectral illuminance of the LED light source to be detected can be obtained according to the illuminance of the plurality of monochromatic narrow-wave light radiations. The signal processing module may be further configured to calculate corresponding luminous fluxes from the illuminance of the plurality of monochromatic narrow-wave light radiations, and integrate the luminous fluxes to obtain luminous fluxes of the LED light source to be measured.
According to another aspect of the present invention, embodiments of a method of measuring luminous flux of an LED light source are also provided herein.
Referring to fig. 5, fig. 5 is a flow chart illustrating 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 luminous flux of the LED light source provided in this embodiment may include the steps of:
501: the luminous flux measuring device of the LED light source provided by any one of the embodiments is calibrated by adopting a 2 pi standard light source;
502: turning off a 2 pi standard light source, and enabling the LED light source to be tested to emit light radiation into the hollow sphere;
503: acquiring light radiation diffusely reflected by the hollow sphere from the interior of the hollow sphere by adopting an illuminance detector;
504: obtaining light radiation diffusely reflected by the hollow sphere from the illuminance detector by using a spectral radiometer to measure spectral irradiance at the illuminance detector; and
505: the luminous flux of the LED light source is determined from the spectral irradiance.
In one embodiment, when the measuring staff adopts the 2 pi standard light source to calibrate the luminous flux measuring device of the LED light source, the 2 pi standard light source can be adopted to emit full spectrum radiation of visible light wave band (380 nm-780 nm) to the interior of the hollow sphere; then, an illuminance detector is adopted to obtain the light radiation emitted by the 2 pi standard light source diffusely reflected by the hollow sphere from the hollow sphere; and further, a spectrum radiometer is adopted to obtain the light radiation emitted by the 2 pi standard light source from the illumination detector so as to measure the spectrum irradiance.
As mentioned above, the standard light source of the luminous flux measuring device of the LED light source is a traceable 2 pi standard light source, the spectrum radiation illuminance value of the standard light source in the visible light band (380 nm-780 nm) is accurately calibrated, and a user can know the radiation illuminance value corresponding to the standard light source according to any required wavelength. Thus, the measurement personnel can compare the spectral irradiance measured by the spectral radiometer with the spectral irradiance of a known 2 pi standard light source, thereby calibrating the spectral radiometer.
In a preferred version of this embodiment, the measurer can first supply dc power to the halogen tungsten lamp source in the 2π standard source to generate stable full spectrum radiation in the visible band; the backward light radiation generated by the halogen tungsten lamp light source is totally reflected to the inside of the hollow sphere by adopting the reflection cup so as to generate the light radiation facing the space angle of 2 pi in the inside of the hollow sphere; and preferably, the light source of the halogen tungsten lamp generates light radiation and the light radiation reflected by the reflecting cup is subjected to diffuse transmission treatment by adopting a light homogenizer so that the 2 pi standard light source forms a lambertian radiator. That is, the radiation intensity of the outgoing light of the 2π standard light source is proportional to the cosine of the outgoing angle at this time, thereby generating more uniform light radiation to obtain higher test accuracy.
In one embodiment, a measuring person may first use a monochromator to separate the light radiation diffusely reflected by the hollow sphere into a plurality of monochromatic narrow-wave light radiation when measuring the spectral irradiance at the illuminance detector; and then respectively measuring illumination intensities of a plurality of monochromatic narrow-wave light radiation to obtain the spectral irradiance at the illuminance detector on the inner wall of the integrating sphere.
In a preferred embodiment of the present embodiment, the signal processing module of the spectral radiometer may be further preferably configured to correct the nonlinear response of the spectral radiometer according to a linear correction method in order to further subtract the saturated nonlinear response of the spectral radiometer, the interference of dark current and noise, thereby obtaining a higher test accuracy.
Referring further to fig. 6, fig. 6 is a flow chart illustrating a method for linear correction according to an embodiment of the invention.
As shown in fig. 6, the above-mentioned linearity correction method may include the steps of:
601: performing large-illuminance range dimming by adopting a spectrum radiation illuminance lamp with calibration completed, and measuring a plurality of actually measured illuminance values by using a spectrum radiometer;
602: determining an ideal response linear range of the spectrum radiometer according to the measured illuminance value;
603: determining a saturation response correction coefficient of the illuminance saturation part according to the actually measured illuminance value larger than the ideal response linear range and the recursive illuminance value of the ideal response linear range;
604: determining a noise response correction coefficient of the dark current and noise part according to the measured illumination value smaller than the ideal response linear range and the recursive illumination value of the ideal response linear range; and
605: the nonlinear response of the illuminance saturation portion is corrected based on the saturation response correction coefficient, and the nonlinear response of the dark current and the noise portion is corrected based on the noise response correction coefficient.
Before measuring the luminous flux parameters of the LED light source to be measured, a measurer can firstly use the traced high-precision luminosity detector as a standard device to calibrate the spectral radiant illuminance lamp, so as to obtain the spectral radiant illuminance of the spectral radiant illuminance lamp.
It will be appreciated by those skilled in the art that the above step of calibrating the spectral radiant illuminance lamp is only one specific scheme for obtaining the spectral radiant illuminance of the spectral radiant illuminance lamp, and is not intended to limit the need to recalibrate the spectral radiant illuminance lamp each time the above linear correction method is performed. In embodiments where the spectral irradiance of the spectral irradiance lamp is known, the step of calibrating the spectral irradiance lamp described above may be omitted and the ideal linear range of response of the spectral radiometer may be determined directly from the measured irradiance value.
In the process of measuring the luminous flux parameter of the LED light source to be measured, a measurer can acquire a plurality of actually measured illuminance values from the minimum illuminance range of the spectrum radiometer to the maximum illuminance range of the spectrum radiometer by carrying out dimming in a large illuminance range on the spectrum radiometer. By fitting these measured illuminance values by a least squares method, a linear equation of these measured illuminance values can be obtained. The measurer can then determine the ideal response linear range of the spectral radiometer based on the difference between these measured illuminance values and the recursive illuminance values of the linear equation.
In one embodiment, the measurer may define that the measured illuminance value is within the ideal response linear range of the spectral radiometer 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 (i.e., the linearity is greater than 99.9%).
It will be appreciated by those skilled in the art that the above criterion of linearity greater than 99.9% is only a specific case provided in this embodiment, and is mainly used to clearly illustrate the concept of the present invention and provide a specific solution for public implementation, and is not intended to limit the scope of the present invention. In other embodiments, the measurement personnel can also set the decision criterion for the ideal response linear range to be 99% lower, or 99.99% higher, or even 99.999% higher, depending on the actual measurement accuracy requirements of the LED light source luminous flux.
After determining the ideal response linear range of the spectral radiometer, the measurement personnel may determine a irradiance greater than the ideal response linear range as the saturated portion. Because the actually measured illuminance value of the saturated portion is saturated due to the radiation illuminance of the spectrum radiometer, an error with smaller measurement value is generated, and a measurer can determine a saturation response correction coefficient of the illuminance saturated portion according to the actually measured illuminance value and a recursive illuminance value of an ideal response linear range, so as to correct the actually measured illuminance value of the illuminance saturated portion when the LED light source to be measured is actually measured.
Similarly, a measurer can determine illuminance less than the ideal response linear range as dark current and noise portions. Because the measured illumination values of the dark current and noise parts can generate errors with smaller measurement values due to the dark current and noise of the spectrum radiometer, a measurer can determine noise response correction coefficients of the dark current and noise parts according to the measured illumination values and the recursive illumination values of the ideal response linear range, and the noise response correction coefficients are used for correcting the measured illumination values of the noise parts when the LED light source to be measured is actually measured.
It will be appreciated by those skilled in the art that the linear correction method described in the above embodiments, which is performed manually by a measurer, may also be performed automatically by the signal processing module of the spectroradiometer according to software installed therein. That is, the signal processing module of the spectral radiometer may be configured to automatically perform the linearity correction method provided by the above-described embodiments.
In a preferred embodiment, the signal processing module may be further configured to integrate the spectral irradiance to obtain a total illumination intensity at the illuminance detector, and further determine the luminous flux of the LED light source according to the illumination intensity at the illuminance detector and the area inside the hollow sphere.
While, for purposes of simplicity of explanation, the methodologies are shown and described as a series of acts, it is to be understood and appreciated that the methodologies are not limited by the order of acts, as some acts may, in accordance with one or more embodiments, occur in different orders and/or concurrently with other acts from that shown and described herein or not shown and described herein, as would be understood and appreciated by those skilled in the art.
The previous description of the disclosure is provided to enable any person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the spirit or scope of the disclosure. Thus, the 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 light flux measuring device of an LED light source, comprising:
the hollow sphere is internally provided with a diffuse reflection coating, and the sphere wall of the hollow sphere is provided with at least three mounting holes;
the light source comprises a 2 pi standard light source, a first mounting hole and a second mounting hole, wherein the 2 pi standard light source is arranged outside the hollow sphere, and the light source comprises a halogen tungsten lamp light source, and the light emitting surface of the halogen tungsten lamp light source faces the inside of the hollow sphere so as to emit full spectrum radiation to the inside of the hollow sphere;
the measuring platform is arranged outside the hollow sphere through a second mounting hole of the hollow sphere, the light-emitting surface of the measuring platform faces the inside of the hollow sphere, the measuring platform comprises a temperature control sheet and an adjustable electrode, the temperature control sheet is used for controlling the junction temperature of a chip of an LED light source to be measured to be constant, the adjustable electrode is arranged above the temperature control sheet and comprises metal sliding sheets respectively arranged at two ends of the temperature control sheet, the two metal sliding sheets are respectively connected with an anode and a cathode of an external direct-current power supply and support to slide left and right in the horizontal direction to adjust the relative position of the metal sliding sheets, so that the chip pins of the LED light source to be measured with different packaging structures and/or sizes are electrically connected, and the LED light source to be measured is pressed on the temperature control sheet to ensure the accurate constant temperature control of the temperature control sheet on the LED light source to be measured;
The illumination detector is arranged outside the hollow sphere through a third mounting hole of the hollow sphere, and the light incident surface of the illumination detector is connected with the inside of the hollow sphere; and
a spectral radiometer connected to the illuminance detector by an optical fiber and comprising a monochromator, wherein the spectral radiometer is configured to: projecting full spectrum radiation emitted by the halogen tungsten lamp light source on an entrance slit of the monochromator; separating the full spectrum radiation into narrow wave light radiation corresponding to the LED light source to be tested through the monochromator so as to simulate the luminous characteristic of the LED light source to be tested; and calibrating the spectrum radiometer according to the known spectrum irradiance of the halogen tungsten light source in the narrow-wave light radiation and the actually measured spectrum irradiance of the narrow-wave light radiation obtained by separation.
2. The luminous flux measurement device of an LED light source according to claim 1, wherein the 2Ω standard light source further comprises:
the light homogenizer is arranged on the light emitting surface of the 2 pi standard light source and in front of the halogen tungsten lamp light source, is connected with the first mounting hole and is used for performing diffuse transmission treatment on light emitted into the hollow sphere so that the radiation intensity of the emergent light of the 2 pi standard light source is in direct proportion to the cosine value of the emergent angle; and
And the reflecting cup is arranged behind the halogen tungsten lamp light source and is used for reflecting all light emitted by the halogen tungsten lamp light source into the hollow sphere.
3. The LED light source luminous flux measurement device of claim 1, wherein the measurement platform further comprises:
and the insulating heat conduction layer is arranged above the temperature control sheet and is used for placing the LED light source to be tested and conducting heat emitted by the LED light source to be tested to the temperature control sheet.
4. The light flux measuring device of an LED light source according to claim 1, wherein the illuminance detector includes:
an adapter connecting the third mounting hole of the hollow sphere and the optical fiber; and
the radiation correction piece is arranged on the light incident surface of the illuminance detector and connected with the incident end surface of the optical fiber, and the radiation correction piece is used for performing cosine correction and homogenization treatment on the light radiation incident to the illuminance detector.
5. The LED light source luminous flux measurement device of claim 1, wherein the spectral radiometer further comprises:
the light guide device is connected with the emergent end face of the optical fiber and is arranged at the front end of the monochromator and used for guiding the optical radiation in the optical fiber into the spectrum radiometer;
The detection module is arranged at the emergent slit of the monochromator and is used for detecting the radiation illuminance of the plurality of monochromatic narrow-wave light radiation and converting the radiation illuminance of the plurality of monochromatic narrow-wave light radiation into corresponding digital signals; and
and the signal processing module is in communication connection with the detection module and is configured to calculate the luminous flux of the LED light source to be detected according to the radiant illuminance of the plurality of monochromatic narrow-wave light radiations.
6. A method of measuring luminous flux of an LED light source, comprising:
scaling a luminous flux measurement device of the LED light source of any one of claims 1-5 with a 2 pi standard light source;
turning off the 2 pi standard light source, and enabling the LED light source to be tested to emit light radiation into the hollow sphere;
acquiring light radiation diffusely reflected by the hollow sphere from the interior of the hollow sphere by adopting an illuminance detector;
obtaining the light radiation diffusely reflected by the hollow sphere from the illuminance detector with a spectral radiometer to measure spectral irradiance at the illuminance detector; and
and determining the luminous flux of the LED light source according to the spectral irradiance.
7. The method of measuring the luminous flux of an LED light source as set forth in claim 6, wherein the step of calibrating the luminous flux measuring device of the LED light source includes:
The 2 pi standard light source emits full spectrum radiation of visible light wave band to the interior of the hollow sphere;
acquiring light radiation emitted by the 2 pi standard light source diffusely reflected by the hollow sphere from the interior of the hollow sphere by adopting the illuminance detector;
acquiring light radiation emitted by the 2 pi standard light source from the illuminance detector by adopting a spectrum radiometer so as to measure the spectrum irradiance thereof; and
the spectral radiometer is scaled according to the known spectral irradiance of the 2 pi standard light source and the spectral irradiance measured by the spectral radiometer.
8. The method of measuring luminous flux of an LED light source according to claim 7, wherein the causing the 2Ω standard light source to emit full spectrum radiation of a visible light band into the hollow sphere comprises:
powering a tungsten halogen light source of said 2 pi standard light source to produce full spectrum radiation in the visible band;
reflecting light radiation generated by the halogen tungsten lamp source towards the inside of the hollow sphere by adopting a reflecting cup so as to generate light radiation of 2 pi space angles towards the inside of the hollow sphere; and
and performing diffuse transmission treatment on the light radiation generated by the halogen tungsten lamp light source and the light radiation reflected by the reflecting cup by adopting a light homogenizer so that the radiation intensity of the emergent light of the 2 pi standard light source is in direct proportion to the cosine value of the emergent angle.
9. The method of measuring luminous flux of an LED light source of claim 6, wherein the measuring the spectral irradiance at the illuminance detector further comprises:
performing large-illuminance range dimming by adopting a spectrum radiation illuminance lamp with calibration completed, and measuring a plurality of actually measured illuminance values by using the spectrum radiation meter;
determining an ideal response linear range of the spectral radiometer according to the measured illuminance value;
determining a saturation response correction coefficient of an illuminance saturation portion according to the measured illuminance value greater than the ideal response linear range and the recursive illuminance value of the ideal response linear range;
determining a noise response correction factor for the dark current and noise portion based on the measured luminance value less than the ideal response linear range and the recursive luminance value of the ideal response linear range; and
and correcting the nonlinear response of the illuminance saturation portion according to the saturation response correction coefficient, and correcting the nonlinear responses of the dark current and the noise portion according to the noise response correction coefficient.
10. The method of claim 9, wherein said determining an ideal linear response range of the spectral radiometer from the measured illuminance value comprises:
Fitting a plurality of measured illuminance values measured by the spectrum radiometer by adopting a least square method so as to obtain a linear equation of the measured illuminance values; and
and determining an ideal response linear range of the spectrum radiometer according to the difference value between the measured illumination value and the recursive illumination value of the linear equation.
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| CN111811786A (en) * | 2020-08-20 | 2020-10-23 | 深圳市路美康尔医疗科技有限公司 | Exposure intensity calibration method for ultraviolet disinfection cabinet |
| CN112629832A (en) * | 2020-12-16 | 2021-04-09 | 南京信息职业技术学院 | Device for detecting uniformity of medical cold light source and calibration method |
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| CN202599522U (en) * | 2012-03-21 | 2012-12-12 | 中国计量科学研究院 | Spherical photometer for measuring luminous flux of LED |
| CN202678401U (en) * | 2012-05-31 | 2013-01-16 | 泰州赛龙电子有限公司 | Packaging structure for high-power LED |
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