Visual inspection lighting device based on reflective light and transmission light

Abstract

The invention relates to a visual checking lighting device, which is based on reflective light and transmission light. Wherein, it is characterized in that: the upper part of frame (1) is arranged with the light emitter (2) for emitting light and the incline mirror (3) opposite to the emitter; the lower part of frame is arranged with the incline transmission light mirror (5) for checking object; and a Fresnel lens (6) is arranged between the mirror and the transmission light mirror.

Description

technical field [0001] The present invention relates to an illumination device for visual inspection of various inspection objects such as polarizing films and liquid crystal substrates, and more particularly to an illumination device for visual inspection based on both reflected light and transmitted light. Background technique [0002] In conventional inspections for detecting defects in inspection objects such as polarizing films, in most cases, a transilluminator equipped with a milky white acrylic diffuser in a trichromatic fluorescent lamp is used so as to use light emitted from the fluorescent lamp Scattering sheet and through the scattered light of the above inspection object for visual inspection. [0003] On the other hand, Patent Document 1 describes a method of inspecting an optical sheet constituted by laminating polarizing reflective sheets as an inspection object and irradiating light obliquely thereon to inspect defects based on light reflected from the optic...

AI Technical Summary

Problems solved by technology

[0006] 1) Illuminators using milky white acrylic diffusers in tri-primary fluorescent lamps can only be used for inspections based on transmitted light

[0007] 2) Due to the use of fluorescent lamps for lighting, the color cannot be changed to colors of different wavelengths suitable for various defect types when performing inspections

On the other hand, the light of fluorescent lamps is scattered light, and convergent light other than scattered light, which is effective for defect observation, cannot be irradiated.

Furthermore, since the light diverges, the illuminance decreases in inverse proportion to the square of the distance between the above-mentioned illumination source and the above-mentioned inspection object, and inspection at a sufficient illuminance level cannot be performed.

[0008] 3) In the lighting of fluorescent lamps, the color temperature is 3000 to 5000°K, and the light of 6000°K close to sunlight suitable for inspection cannot be obtained

In this way, when observing defects, the defect visibility and color visibility are low, and the defect omission rate is high

[0010] 5) In the inspection based on transmitted light, the vertical position (concavity and convexity) of the defect cannot be distinguished according to the type of defect of the inspection object

Furthermore, since only scattered light can be used, it is easy to miss tiny defects

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