CN204924913U - Object optical characteristic measuring device - Google Patents

Abstract

The utility model monitors the fluctuation of the electric parameters of the light source by configuring the light source electric parameter monitoring device. During the test, after the light source is stably emitting light, select a suitable time window to open the light measuring device for signal acquisition and measurement, and use the monitoring results to correct the light. The data measured by the measuring device; at the same time, it can also cooperate with the temperature control device to realize the stable output of the light source through the feedback adjustment mechanism of the temperature control device and the light source electrical parameter control device, which reduces the cost and improves the test accuracy. It can be widely used It is suitable for measuring the optical properties of various objects, and has the characteristics of convenient operation, wide application range, low cost and high measurement accuracy.

Description

An object optical characteristic measuring device

【Technical field】

The invention relates to the field of object optical characteristic detection, in particular to an object reflectance, transmittance and color measurement device.

【Background technique】

The needs of daily production and life make people often need to measure and evaluate the optical properties of objects. The measurement of optical properties is widely used in the quality control of products in chemical, food, plastic, coating, construction and other industries. The traditional measurement of optical characteristics, such as color control, is judged by the operator after visually observing the sample. The judgment result is highly subjective, and the evaluation results will also vary with time, environment or personnel changes, resulting in evaluation There is a greater risk of inaccuracy. The modern development of science and technology has also led to the continuous improvement of the measurement level of optical characteristics. From relying on visual judgment in the past to modern color management with the help of specific instruments, the evaluation results have gradually transitioned from subjectivity to objectivity. Reliability has been greatly improved.

At present, the general object optical characteristic measurement instruments on the market usually use a spectrometer as a light measurement device. The spectrometer measures the spectrum or photometric characteristics of the light after the sample is acted on by the spectrometer, and uses these spectral test data to calculate the tristimulus value of the object. According to the number of spectrometers used, there are two main types of common color measurement devices: the first one uses two spectrometers, one of which is used as a light measuring device to receive the light after the sample has been acted on, and the other spectrometer is used as a monitoring device to receive the light source light and monitor changes in the light source to correct measurements. By setting up two spectrometers, the light acting on the sample and the light directly emitted by the light source can be measured separately through two optical paths without interfering with each other. Although this kind of device can obtain high measurement accuracy, the cost of using two spectrometers is too high. At the same time, the volume of the instrument is large, which affects the convenience of measurement; another common color measurement device only uses a spectrometer, which reduces the cost and reduces the volume of the instrument. The receiving channel, the two optical receiving channels will inevitably interfere with each other to a certain extent, which will affect the accuracy of the measurement.

【Content of invention】

Aiming at the deficiencies of the above-mentioned prior art, the present invention aims to provide a device for measuring the optical properties of an object. Only one light measuring device is required to complete the measurement of the optical properties of the sample to be tested. By setting the light source electrical parameter monitoring device, the light source can be monitored During the working process, the electrical parameters change, and after the light source emits light stably, select an appropriate time window to turn on the light measuring device for signal acquisition and measurement, and use the monitoring results of the light source electrical parameter monitoring device to correct the measurement results of the light measuring device. The invention improves the measurement accuracy while reducing the cost.

The present invention is achieved through the following technical solutions: a device for measuring optical characteristics of an object, which is characterized in that it includes a light source group, a light measuring device and a light source electrical parameter monitoring device, and the light source group emits light of a specific spectrum and irradiates the object On the test sample, the light measurement device receives the light from the light source group and the light after being acted on by the sample to be tested, and the light source electrical parameter monitoring device monitors the working electrical parameters of the light source in the light source group.

In the present invention, the electric parameter monitoring device of the light source is used to monitor the change of the electric parameter in the working process of the light source. Taking LED light sources as an example, in actual measurement, due to thermal drift, voltage or current fluctuations, mechanical vibration or air pressure differences, the characteristics of LED light sources will decay over time, affecting the repeatability or consistency of test results. As can be seen from Figure 1, the junction temperature of an LED has a significant effect on light output. The invention not only monitors the stability of the luminous spectrum of the light source by configuring the light source electrical parameter monitoring device, but also uses the data obtained through monitoring to correct the spectral data measured by the measuring device, thereby improving the accuracy of measurement. In addition, since only one light measuring device is provided, the cost can be greatly reduced.

The present invention can also be further defined and perfected by the following technical solutions:

As a technical solution, the light source group includes at least one LED light source. Existing equipment for measuring the optical characteristics of objects mostly uses a flashlight, that is, a pulsed light source, as a light source for testing. Before the test, the number of flashes or pulses is set to complete the sampling measurement within one or more pulse time windows. The pulse width is small and the measurement time is short, so the measurement accuracy cannot be well guaranteed. The present invention selects the LED light source as the light source for testing, and adopts DC drive for the LED light source. In the initial stage of electrification, the output performance of the LED will change significantly. After a period of time, the output performance change will tend to be stable. An appropriate time window starts the signal acquisition and measurement work, which can ensure that the measurement is carried out in a longer time window, and improves the accuracy of the test.

As a technical solution, the light source group includes at least one LED white light source and one LED independent supplementary light source, and the combination of the LED white light source and the LED independent supplementary light source emits light to irradiate the tested sample. LED white light source has a full spectral distribution in the 380-780nm band, and has the characteristics of high luminous efficiency, rich spectrum, small size, and easy control and drive. It should be pointed out that for the tested samples with obvious color selection characteristics, the spectral power distribution of a specific light source cannot match the color characteristics of the measured object, resulting in the measured optical characteristics inconsistent with the actual perception of the human eye , that is, it cannot accurately reflect the characteristics of the measured sample such as gloss, transmission, and reflection, resulting in measurement errors. Therefore, by using supplementary light source and white light source to emit light, a light source closer to the optical characteristics of the sample to be tested is obtained, and the test accuracy is improved. For example, if a sample that mainly reflects purple light is selected, the spectral sensitivity of the purple light region is increased by adding a purple light source while being irradiated by a white light source. The light source can more significantly present the optical characteristics of the sample to be measured, thereby obtaining high-accuracy optical characteristic parameters. Preferably, the supplementary light band of the independent supplementary light source should cover the band with lower spectral sensitivity in the independent white light source, so as to achieve the purpose of improving the spectral responsivity of the band to be supplemented with light.

Preferably, the light source group includes more than one independent narrow-wave source, and the more than one independent narrow-wave source emits separate narrow-band spectrum, and the combined band spectrum of the light source group is corrected by using the narrow-band spectrum. For example, the combination of white LED light source and purple LED light source is selected as the light source group to emit light. When measuring, firstly, only the purple light source is used as the light source. At this time, it can be considered that the spectral response rate is zero except for the band where the purple light source is located. If so When there is spectral responsivity in other bands, it can be considered that there is noise or stray light in these bands. Therefore, when the combination of white light source and purple light source is used as the incident light source, the error caused by noise other than the purple light should be removed from the measured optical characteristic value of the object at this time, thereby further improving the measurement accuracy.

Preferably, the object reflective color measurement geometric condition of d/8 or 8/d or d/0 or 0/d or 45/0 or 0/45 is formed between the light source group and the corresponding measuring device and the measured sample , and d/0 or 0/d or 0/0 and other object transmission color measurement geometric conditions to meet the current international and domestic actual measurement needs.

As a technical solution, it also includes a temperature control device, the temperature control device is arranged on the light source group, and the temperature control device controls the working temperature of the LED light source according to the relationship between the junction voltage and junction temperature of the LED light source. Due to the stability factor of the LED light source itself, changes in voltage or frequency, changes in local humidity or other environmental conditions will have a significant impact on the output characteristics of the light source, so by setting the temperature control device, using the LED light source junction voltage and junction temperature Correlation relationship, to realize the control of the working temperature of the LED light source. It should be pointed out that the temperature control device can also be used to compensate and adjust the influence of the LED junction temperature due to the change of the environmental state.

As a technical solution, the light source electrical parameter monitoring device is electrically connected to the temperature control device, and the temperature control device controls the working temperature of the light source by cooling or heating according to the light source electrical parameter information measured by the light source electrical parameter monitoring device. Electrically connect the light source electrical parameter monitoring device with the temperature control device, and through the mutual feedback of the two, stable light source output characteristics can be obtained. The specific method is: a constant current is passed into the light source group, and the light source electrical parameter monitoring device monitors the light source group. The electrical parameters of the light source fluctuate. The light source electrical parameter monitoring device feeds back the measured electrical parameter information to the temperature control device. The temperature control device adjusts the working temperature of the light source in the light source group by cooling or heating according to the actual measurement results. After adjusting the temperature, the electrical parameter fluctuation of the light source in the light source group, after multiple feedbacks and adjustments by the light source electrical parameter monitoring device and the temperature control device, the electrical parameter fluctuation of the light source in the light source group tends to be stable, that is, the working temperature of the LED light source tends to be stable, and then turn on the optical measuring device to measure the optical characteristics of the tested sample. Taking the LED light source as an example, this feedback adjustment method utilizes the relationship between the LED junction temperature and the junction voltage. When the light source is stable, the data measured by the light measurement device is the measurement data of the optical characteristics of the object under the stable state of the LED light source. . Compared with no temperature control device, accurate measurement can be realized without using the data measured by the light source electrical parameter monitoring device to calibrate the light measuring device at this time.

As a technical solution, the light measurement device starts the signal acquisition and measurement work after the light source of the waiting light source group is turned on and stabilized. Since the output performance of the LED is not stable at the initial stage of power-on, after a short period of time, the output performance change will tend to be stable. At this time, select a suitable time window in the stable stage and turn on the light measuring device for signal Collect measurement work. The present invention is essentially different from the traditional pulse light source measurement. The pulse light source measurement is to complete the measurement in one or more pulse time windows by setting the number of pulses before the test. Since the pulse width in the measurement process is small, the actual measurement time Short, so the measurement accuracy can not be well guaranteed. The invention can ensure that the measurement is carried out in a relatively long time window, and the test accuracy is further improved.

Preferably, the light measuring device is a spectroradiometer or a spectroradiometric measurement module, which can measure the spectral information of the sample to be measured, and obtain color information related to the spectral information according to the obtained spectral information, such as the spectral information of the sample to be measured Reflectance, transmittance, color coordinates, etc.

As a technical solution, the electrical parameter monitoring device of the light source monitors the electrical parameters of the light sources in the light source group, calculates the actual luminous spectrum of the light source according to the dependence relationship between the electrical parameters of the light source and the luminous spectrum of the light source, and corrects the measurement of the light measuring device result. When the light source used is different, the monitoring parameters of the light source electrical parameter monitoring device also change accordingly: when the light source is an LED, the light source electrical parameter monitoring device monitors the current or voltage of the LED; when other types of light sources are used, such as tungsten lamp The light source electric parameter monitoring device monitors electric power. The light source electrical parameter monitoring device monitors the fluctuation of the electrical parameters of the light source group, and the electrical parameters obtained through monitoring can be converted into optical parameters by using the dependence relationship between the electrical parameters of the light source and the luminous spectrum of the light source, and then the actual luminous spectrum of the light source can be calculated; and the optical measurement What the device measures is the spectrum of the light source after being affected by the sample to be tested, and the former can be used to correct the latter to obtain more accurate measurement results.

Preferably, when the light source group uses LED light source as the light source for detection, the light source electrical parameter monitoring device monitors the working electrical parameters of the LED light source in the light source group, and according to the electrical parameters of the LED light source, the junction temperature of the LED light source and the light emission of the LED light source The dependence of the spectrum, calculate the actual luminous spectrum of the LED light source, and correct the measurement results of the light measuring device. In view of the output characteristics of the LED light source, there is a close relationship between its junction temperature and electrical parameters. Through the conversion of electrical parameters and optical parameters, the actual luminous spectrum of the LED light source can be calculated, and the measurement results of the light measuring device can be corrected.

To sum up, the present invention utilizes a combined LED light source as the light source for detection. When only one spectrometer is set as the light measuring device, the electrical parameter monitoring device for the light source is configured to monitor the fluctuation of the electrical parameters of the light source for detection. After emitting light, select the appropriate time window to start the signal acquisition and measurement work, and use the monitoring results to correct the data measured by the light measurement device. At the same time, it can also cooperate with the temperature control device through the feedback adjustment mechanism of the temperature control device and the light source electrical parameter control device. The stable output of LED light source improves the test accuracy. It can be widely applied to the measurement of optical properties of various objects, and has the characteristics of convenient operation, wide application range and high measurement accuracy.

【Description of drawings】

Accompanying drawing 1 is the temperature dependence characteristic curve of white high-power LED luminous flux and CCT;

Accompanying drawing 2 is the schematic diagram of embodiment 1;

Accompanying drawing 3,4 are the schematic diagrams of embodiment 2;

Accompanying drawing 5 is the schematic diagram of embodiment 3;

Accompanying drawing 6 is the schematic diagram of embodiment 4;

Accompanying drawing 7 is the schematic diagram of embodiment 5.

1-light source group; 11-LED white light source; 12-LED supplementary light source; 2-light measuring device; 3-light source electrical parameter monitoring device; 4-tested sample; 5-temperature control device; 6-integrating sphere; 7- Light trap; 8 - measured transmitted sample.

【Detailed ways】

Example 1

As shown in Figure 1, this embodiment discloses a schematic diagram of the working principle of a device for measuring optical characteristics of an object, including a light source group 1, an optical measurement device 2, and a light source electrical parameter monitoring device 3. The light source group 1 includes an LED light source, and consists of Constant current drive. When working, a constant current is passed into the light source group 1, and the light source electrical parameter monitoring device 3 monitors the voltage fluctuation of the light source group 1. At the initial stage of power-on, the output performance of the LED will increase significantly. After a short period of time, The change in output performance will tend to be stable. At this time, select a suitable time window in the stable stage to turn on the optical measurement device 3 for signal acquisition and measurement. After the measurement is completed, use the data obtained from monitoring to correct the spectral data measured by the optical measurement device 2 .

Example 2

Different from Embodiment 1, this embodiment also includes a temperature control device 5 . As shown in Figures 3 and 4, when working, a constant current is passed into the light source group 1, and the light source electrical parameter monitoring device 3 monitors the voltage fluctuation of the light source group 1, and feeds back the measured voltage information to the temperature control device 5, and the temperature control The device 5 adjusts (heats or cools) the temperature of the light source in the light source group 1 according to the actual measurement results, and the light source electrical parameter monitoring device 3 monitors again the voltage fluctuation of the light source in the light source group 1 after the temperature is adjusted. After multiple feedbacks and adjustments by the temperature control device 5, the voltage fluctuation of the light source turned on in the light source group 1 tends to be stable (V _F =V _F (0)). Measurement.

Example 3

As shown in Figure 5, a device for measuring optical characteristics of an object is disclosed in this embodiment, including a light source group 1, an optical measurement device 2, a light source electrical parameter monitoring device 3, an integrating sphere 5 and an optical trap 6, and the light source group 1 consists of four Composed of independent light sources, which are an LED white light source 11, three independent supplementary light sources 12 such as red LEDs, green LEDs and blue LEDs, the light source group 1 is located in the incident direction with an angle of 8° between the normal line of the tested sample 4 Above, the light measuring device 2 is located on the horizontal exit port of the integrating sphere 5, the light source group 1, the measuring device 2 and the sample 4 to be tested form a color measurement geometric condition of 8/d; the light measuring device 2 is a spectroradiometer.

When measuring, turn on the LED white light source 11 in light source group 1 alone, or turn on the LED white light source 11 and one or more independent LED supplementary light sources 12 at the same time, and irradiate the tested sample 4, and the reflected light of the tested sample 4 passes through the integrating sphere 5 After sufficient diffuse reflection, it is received and measured by the optical measuring device 2, wherein the specularly reflected light of the measured sample 4 is absorbed by the light trap 6 located symmetrically with the direction of the light source group 1, so as to eliminate the influence of specular reflection.

This embodiment also includes a light source electrical parameter monitoring device 3 for monitoring the fluctuation of the electrical parameters of each independent light source in the light source group 1. After the measurement is completed, the data obtained by monitoring can be used to correct the spectral data measured by the measuring device. The system of this embodiment has a simple and compact structure, high repeatability and consistency of test results, and fast measurement speed, and is suitable for industrial production lines and on-site rapid and laboratory measurements. Example 4

As shown in FIG. 6, this implementation implements the transmission measurement of d/0. It includes a light source group 1, an optical measurement device 2, a light source electrical parameter monitoring device 3, an integrating sphere 5, and a transmission sample 7 to be measured. During measurement, the light source group 1 is located in the incident direction at 90° to the horizontal light outlet of the integrating sphere 5, and is The transmission sample 7 is located on the horizontal exit port of the integrating sphere 5 , the light measuring device 2 is located on the optical path behind the transmission sample 7 to be measured, and the light source electrical parameter monitoring device 4 is set to monitor the electrical parameter fluctuation of each independent light source in the light source group 1 .

Example 5

As shown in Figure 7, different from Embodiment 4, this embodiment implements 45/0 color measurement. Light source group 1 is composed of a white LED light source 11 and a purple LED supplementary light source 12. During measurement, light source group 1 is located at In the direction of incidence with an included angle of 45° between the normal line of the sample 4 to be tested, the emitted light is received and received by the light measuring device 2 set on the normal line of the sample 4 (that is, 0°) after being reflected by the sample 4 to be tested. Measurement.

In this embodiment, the tested sample mainly chooses to reflect purple light. During the test, while turning on the LED white light source 11 for irradiation, the spectral sensitivity in the purple light region is increased by supplementing the purple light supplementary light source 12 .

It should be emphasized that the above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention are all valid. Still belong to the scope of the technical solution of the present invention.

Claims (11)

1. A device for measuring optical properties of an object, characterized in that it comprises a light source group (1), a light measurement device (2) and a light source electrical parameter monitoring device (3), and the described light source group (1) sends out light of a specific spectrum And irradiate the tested sample (4), the light measuring device (2) receives the light from the light source group (1) and the light after the tested sample (4) acts on it, the light source electrical parameter monitoring device (3) monitors the light source group (1 ) Working electrical parameters of the light source. 2. The device for measuring optical properties of an object according to claim 1, characterized in that, said light source group (1) includes at least one LED light source. 3. The device for measuring optical characteristics of an object as claimed in claim 2, wherein said light source group (1) comprises at least one LED white light source (11) and one LED independent supplementary light source (12), said LED The white light source (11) and the LED independent supplementary light source (12) combine to emit light to irradiate the required light onto the tested sample (4). 4. The device for measuring optical properties of an object as claimed in claim 2, wherein said light source group (1) comprises more than one independent narrow-wave source, and said more than one independent narrow-wave source sends out a discrete narrow-band spectrum, utilizing The narrow band spectrum corrects the combined band spectrum of the light source group (1). 5. The device for measuring optical properties of an object according to claim 2, 3 or 4, characterized in that the LED light sources in the light source group (1) are driven by constant current. 6. The device for measuring optical properties of an object according to claim 1, further comprising a temperature control device (5), the temperature control device (5) being arranged on the light source group (1), and the temperature The control device (5) controls the working temperature of the LED light source by utilizing the relationship between the junction voltage and the junction temperature of the LED light source. 7. The object optical characteristic measuring device as claimed in claim 6, characterized in that, said light source electric parameter monitoring device (3) is electrically connected with the temperature control device (5), and the temperature control device (5) is based on the light source electric parameter The electrical parameter information of the light source measured by the monitoring device (3) controls the working temperature of the light source in a cooling or heating manner. 8. The object optical characteristic measurement device according to claim 1, characterized in that, the light measurement device (2) starts signal acquisition and measurement work after the light source of the light source group (1) is turned on and stabilized. 9. The object optical characteristic measuring device according to claim 1, characterized in that, the light measuring device (2) is a spectroradiometer or a spectroradiometric measuring module. 10. The device for measuring the optical characteristics of an object according to claim 1, wherein said light source electrical parameter monitoring device (3) monitors the working electrical parameters of the light source in the light source group (1), and according to the light source electrical parameter and the light source light emission The dependence of the spectrum is calculated to calculate the actual luminous spectrum of the light source, and the measurement result of the light measuring device (2) is corrected. 11. The object optical characteristic measuring device as claimed in claim 2 or 10, characterized in that, said light source electrical parameter monitoring device (3) monitors the working electrical parameters of the LED light sources in the light source group (1), and according to the LED light source electrical parameters The parameters depend on the junction temperature of the LED light source and the luminous spectrum of the LED light source, calculate the actual luminous spectrum of the LED light source, and correct the measurement results of the light measuring device (2).