Design of a Multi-Channel High-Power Color-Mixing Optical System Based on RGB LED Arrays

Round 1

Reviewer 1 Report

This manuscript introduces a design method of RGB LED mixing light by using reflector and random microlens. The optical system structure given in this manuscript gives a solution to improve the mixing performance of high-power light source, and the optical design system is analyzed and compared. I suggest that the manuscript should have some minor revision, and I have some concerns regarding the manuscript.

1.The introduction of color mixing with LED is not enough, and the analysis of existing problems is not deeply discussed. It is suggested that the relevant technologies, especially the latest technology of random microlens, should be added in the introduction.

2. In the process of system design, system parameters need to be further given, such as lighting distance, reflector opening size, etc.

3. Color uniformity and illuminance uniformity are relatively important performance indicators, and the analysis conclusion of these properties is not clear enough. It is suggested to conduct more in-depth analysis on the design results.

4. The English writing of this article is unclear in some sentences, so it is suggested to revise the English again.

5. The influence of the contour of the random microlens on the lighting effect is not consistent with the main points analyzed in this paper. 

Author Response

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Reviewer 2 Report

This article presents a method for designing a powerful optical system with multiple channels to achieve high-quality color mixing and uniform illumination of the shape. It has been shown that a multi-channel elliptical reflector provides convergence of light energy from several RGB LED arrays to produce a high-power output beam. It has also been shown that double-layer microlens arrays form the collimated beam into geometric areas of illumination and improve the uniformity of both color and illumination. As a result, this optical system can be implemented in applications such as machine vision illumination, daylight simulation, smart lighting, and so on.

 The work is a comprehensive study of a high-power multichannel optical color mixing system based on RGB LED matrices and can be published in the journal of Photonics.

 A small note concerns the decryption of RGB and TIR.

Author Response

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Reviewer 3 Report

The authors have presented the design and numerical evaluation of a three-stage colored LED mixing system: elliptical mirror + TIR lens + dual-layer random microlens array. The working principle and analysis are convincing. However, a few issues need to be addressed before I can recommend this work for publication. 

1) I do not understand how the "high power" feature is added in the title and abstract. The design focuses on achieving uniformity in illuminance / color distribution. Throughout the article I do not see any structural or material improvement to enhance the high-power capability of the system. The authors need to clarify this.

2) The randomness of the lens array seems to be an important factor and should be investigated further. In the current manuscript, both delta_R and average R are fixed. I wonder how they should affect the uniformity results. 

3) As LED color mixing technology has been developed for decades, the authors need to come with an in-depth comparison and clearly illustrate how their approach stands out among the literature. 

Author Response

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Reviewer 4 Report

Title: Design of multi-channel high-power color mixing optical system based on RGB LED arrays

In this paper, the author presents a design method for a high-power optical system with multiple channels to achieve high-quality color mixing and shape uniform lighting. Simulation results show that the illumination uniformity of all optical systems is more significant than 0.77 and the maximum 11 color difference is 0.014. The idea of this paper is interesting. The manuscript is well organized. The reviewer has some comments below:

1. Author should discuss the recent results in the introduction part. The reference list is too old and needs to update with more recent references.

2. Some recent researches show uniformity above 0.9. This study obtained 0.77. What is the advantage of this study?

3. Is it better to increase the number of channels?

4. I suggest the author compare the performance proposed in this paper with other published works.

5. Why did I see the color mixing in rectangular microlens arrays is not good as hexagonal and cross?

All the best,

The reviewer

Author Response

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Round 2

Reviewer 3 Report

The authors have carefully addressed the three main issues from the last review. I have no further comments.