Qualitative research on color clarity in color quality of LED lighting products (two)

1.Farnsworth100 hue test

In the past research has found that the changes of illumination for the human eye color resolution is very large, so in the process of experiment, the TES1330A meter real-time measurement of illumination, keep it 500lx, so the experiment only considers the changes produced by the different color temperature and spectral resolution of the human eye.

Figure 1 in the light of the light box in the light of the experiment

First, the subjects were tested by the first test light source, and at least one complete test was completed. Before the start of the sorting, the subjects have to go through 15 minutes to fully adapt to the current lighting environment, during which the subjects can only observe the lighting environment in the light box, and can not be interfered by other light sources. To adapt to the full, began sorting test. After the completion of the experiment, the replacement of the next light source, the subjects in this environment to adapt to the current lighting environment, at this time the researchers recorded the results of the experiment, and re disrupt the color chess. The subjects completed a two light source after ordering the rest for 30 minutes, and then continue to test.

Figure 2 the average error score of the subjects' color sorting under the six light sources

The experimental data shown in Figure 2, we can see the color chess sorting error scores in the 4000K color temperature is higher than the 8000K related color temperature, so the color temperature can improve the color resolution of the human eye. In the 8000K group, the color rendering index 80 was higher than that of the color rendering index of the light source, and the color rendering index was not always correlated with the color resolution ability of the 70 groups.

2 color clear subjective feeling evaluation experiment

Figure 3 illumination color clear subjective evaluation comparison selection experimental scenario

In order to let the participants to evaluate the light color clear, light environment therefore need to present a simulation for the subjects, so in a light box placed simulation fruit, canned drinks, magazines, MCC card. This experiment used all 6 COB light source, divided into 4000K group, 8000K group, two light box experiments were selected from a light from the two color group, subjects on both sides of the light environment of contrasting color clear subjective feelings, and subjective feeling of color is more clear halo environment. A light source need different compared with three light sources, and repeat three times, so a light source will be the 9 time comparison, 25 subjects were compared, so a light source will be 9*25=225 times the number of times of comparison, selected a total contrast obtained in addition to the subjects selected evaluation percentage. The experimental results shown in figure 4. From the experimental results, it can be found that the color of high color temperature in the subjective contrast of color clear, almost all the subjects were selected high color temperature light source, and the relationship between the color rendering index CRI is not large.

Figure 4 white LED color clear subjective comparison test results

Three, conclusions and Prospects

Two experiments in this paper can get the following two qualitative conclusions: white LED lighting products, the first high temperature than the low color temperature has a higher color resolution and subjective color definition; second color index and the color definition color definition is not relevant and therefore can not be used to evaluate the color index of LED lighting light source.

Technical report of the International Commission on illumination CIE 177:2007 "color" white LED pointed out that "get CRI for a series of light source contains LED light source color evaluation results are not satisfactory, and the technical report also pointed out that" should be as soon as possible to develop a new color evaluation index or a group evaluation index to replace the existing CRI [3]. According to the results of this study, the light color quality is various, not through an evaluation model to evaluate the color quality evaluation framework of the future should establish a multi evaluation index system, and complete evaluation of white LED light source color quality attributes, provide scientific and objective evaluation standard for LED lighting. (Xu Zhewei / Wang Luo Tao Foshan Steel Research Institute of Zhongshan University)