Using plano-convex cylindrical lens to realize strip light source

►Strip light source using line array LEDs and plano-convex cylindrical lens

In a project on photodiode based in-line micro-pinhole detection, it is necessary to provide the photodiode array with a narrow long strip of light hitting area to ensure that when the product to be inspected on the production line passes through this area, if there is a tiny pinhole, the weak light signal through it can be projected on the surface of the photodiode and converted into an electrical signal. In order to achieve such an effect, that is, the light signal from the light source is distributed as much as possible in such a narrow long strip area, the proposed solution using a strip LED array combined with a plano-convex cylindrical lens to achieve the way.
 

On this point the use of photodiodes for weak light signal detection at home and abroad have been studied, but most of them are for the detection of possible weak light signals, and no specific application to the production line for product detection cases, so there is no corresponding design of its optical path part. The rationality of the optical path design is of great relevance for the detection accuracy and reliability of the complete system. On the basis of the known spherical optical imaging system, it is possible to use a line array LED and a flat convex lens to achieve a strip light area solution. In practice, most cases use a spherical lens to achieve the purpose of light gathering, because of its mature manufacturing method and low cost. Due to the specificity of the project needs, it is difficult to achieve the use of spherical lenses, that is, to converge the light generated by the line array LEDs with a small divergence angle into the required long strip of light-emitting area, and in this line should ensure that the uniformity of light intensity distribution is better. Although commercially available cylindrical lens, but are only given a specific wavelength of light (usually sodium yellow light) corresponding to the focal length . The application of the cylindrical lens is also to obtain a linear strip of light when the incident light is parallel, e.g. in the case of a birefringent crystal optical element face shape test system, the light from the He-Ne laser becomes a horizontal single wavelength line source after passing through the cylindrical lens and is incident on the plane of the optical element to be measured, and the incident light is refracted into two beams (o and e light ) after passing through the optical element of the birefringent crystal. There has not been a system application for imaging a point light source as a strip of light, much less a relevant theoretical derivation giving the location of the imaging. In this project application, it is not the focal length of a cylindrical lens that is needed, because the focal point is defined as the point where the light rays converge on the other side of the lens when one side of the lens is parallel. Therefore, it is necessary to derive the location of the convergence point of the light on the image side for a given point source by theoretical calculations.
 

The parameters of the lens can be selected according to the position of the photodiode array and the position of the light source, and this application of plano-convex cylindrical lenses is of interest in the field of optics.

We specialize in manufacturing high precision optical lenses for a wide range of applications such as medical devices, lasers, aerospace, underwater detectors, photographic surveillance, etc. We can supply the plano-convex cylindrical lenses in the above article.

RZ Optics Co.,Ltd. from sourcing high quality optical materials to inspecting optical components, RZ Optics has a complete production system and some advanced production facilities. We use standard polishing and grinding techniques to provide custom sizes of red flat convex lenses made from a variety of substrate materials: various optical glasses, optical infrared silicon, ultraviolet fused silica (JGS1), infrared fused silica (JGS3), sapphire, and most other optical materials.