Nonsequential Speckle Reduction Method by Generating Uncorrelated Laser Subbeams With Equivalent Intensity Using a Reflective Spatial Light Modulator

Tong, Zhaomin; Song, Shao-Hua; Jia, Suotang; Chen, Xuyuan

doi:10.1109/jphot.2017.2732507

Cited by 6 publications

(2 citation statements)

References 15 publications

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“…The plane which contains both the projection lens and the CCD camera is located 1 m from the the screen. The integration time of the CCD camera was set to be 50 msec to mimic the response time of the human eye [20], while the camera lens had a focal length of 50 mm and the F-number was 11 [1]. The resulting output image was an 8-bit grayscale image.…”

Section: Methodsmentioning

confidence: 99%

Laser speckle reduction utilized by lens vibration for laser projection applications

et al. 2019

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In this paper, a compact speckle reduction method utilizing vibrating lenses for laser beam scanning is proposed and demonstrated. The maximum speckle reduction efficiency was found to be 75.6% and 81.25% for a 532 nm diode-pumped solid-state (DPSS) laser and a 520 nm laser diode (LD), respectively. The minimum speckle contrast ratio observed using our method was 0.11 for the DPSS laser and 0.06 for the LD. The proposed method can provide speckle reduction with minimal power requirements, a low implementation cost, and no bending for the optical path of the laser beam. Additionally, this method is promising to withstand high-power lasers for use in high lumen laser projectors by optimizing the lens parameters. The demonstrated technique has a small form factor while simultaneously demonstrating a high degree of speckle reduction, which shows potential for speckle reduction in mini-and pico-laser projector applications.

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Section: Methodsmentioning

confidence: 99%

Laser speckle reduction utilized by lens vibration for laser projection applications

et al. 2019

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“…Table 2 lists the normalized value of the area of the laser sub-beam A, the equivalent number of independent laser subbeams N theory , and the equivalent number of independent speckle patterns N exp obtained from Figure 4. The equivalent number of independent laser sub-beams N theory is calculated by the assumption of summing M independent speckle patterns with different mean intensity I , such as [28]…”

Section: B Improvement Of Speckle Reduction Using the Roesmentioning

confidence: 99%

Laser Spatial Coherence Suppression With Refractive Optical Elements Toward the Improvement of Speckle Reduction by Light Pipes

Tong

Sun

et al. 2019

IEEE Access

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We study laser speckle reduction by light pipes, and we propose a new method to improve its efficiency. Proof-of-concept refractive optical elements (ROEs) with a staircase-like structure are introduced before a holographic diffuser to split a laser beam into laser sub-beams. Optical paths of the laser sub-beams after transmitting through the ROEs are different, and these partially correlated (or uncorrelated) laser subbeams are added in intensity basis because of the folded mirror reflections by the light pipe. Thus, laser spatial coherence is suppressed, which helps to reduce speckle. We demonstrate this method in a simplified laser projection system, where subjective speckle contrast is reduced from 0.33 to 0.24 before and after introducing a two-dimensional ROE, respectively. Comparing with other improved speckle reduction methods by light pipes, the proposed method is motionless and simpler.INDEX TERMS Speckle reduction, light pipe, refractive optical element.

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Design and implementation of passive speckle reduction in laser projector with refractive optical element and lenslet integrator

Tong

Sun

et al. 2022

Optik

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Nonsequential Speckle Reduction Method by Generating Uncorrelated Laser Subbeams With Equivalent Intensity Using a Reflective Spatial Light Modulator

Cited by 6 publications

References 15 publications

Laser speckle reduction utilized by lens vibration for laser projection applications

Laser speckle reduction utilized by lens vibration for laser projection applications

Laser Spatial Coherence Suppression With Refractive Optical Elements Toward the Improvement of Speckle Reduction by Light Pipes

Design and implementation of passive speckle reduction in laser projector with refractive optical element and lenslet integrator

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