System and method of detecting defect of optical film

A system for detecting a defect of an optical film, the system comprising:

• a lighting unit, which is spaced apart from the optical film, and irradiates light toward one surface of the optical film;
• a screen, which is spaced apart from the other surface of the optical film, and on which the defect existing in the optical film is projected and displayed due to the passage of the light irradiated from the lighting unit through the optical film;
• an imaging unit, which is spaced apart from the screen, and obtains the image of the defect of the optical film projected onto the screen;
• an analyzing unit, which analyzes the obtained image, and detects the defect of the optical film based on a result of the analysis;
• wherein a distance (d1) between the screen and the optical film has a value of 90 mm to 130 mm and a distance (d2) between the lighting unit and the optical film has a value of 280 mm to 340 mm;
• and
• wherein the imaging unit and the screen are disposed at a first angle (θ1), relative to one another, the lighting unit and the optical film are disposed at a second angle (θ2) relative to one another, and the first angle and the second angle have the same value, and wherein the first angle (θ1) and the second angle (θ2) have a value within a range of 25° to 48°, and
• wherein the optical film, and the screen are disposed parallel to each other.