| CPC G02F 1/133788 (2013.01) [G02B 5/20 (2013.01); G02B 5/3058 (2013.01); G03F 7/2002 (2013.01)] | 5 Claims |

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1. A light irradiation device comprising:
a light source with a plurality of LEDS;
a polarizing element that receives light from the light source and applies the light transmitted through the polarizing element to a workpiece; and
an optical filter that transmits light selectively that is part of the light emitted from the light source and has a wavelength of equal to or greater than a predetermined wavelength, wherein
the optical filter is configured in such a manner that, with increase in an incidence angle of the light to the optical filter having the wavelength of equal to or greater than the predetermined wavelength, the transmittance of the light having the wavelength of equal to or greater than the predetermined wavelength is increased.
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