Patent ID: 8280118

Claim:
A biometric authentication device for identifying an individual who is associated with a subject based on a biometric pattern of the subject which is included in a picked up image, comprising: a light guiding unit for outputting, from a surface thereof, light incident on an end face thereof; a liquid crystal display unit for adjusting, on a display pixel basis, an intensity of light output from the surface of the light guiding unit, and then outputting the light in a direction of the subject; an image pickup unit for picking up an image of the subject; a display light source for emitting light used as a backlight of the liquid crystal display unit such that the light is incident on the end face of the light guiding unit; a detection light source for emitting light for irradiating the subject such that the light is incident on the end face of the light guiding unit; and a control unit for controlling processing of the biometric authentication device, wherein: the control unit turns on the detection light when the image pickup unit picks up a first image, which is used for authentication; the control unit turns on the display light source when the liquid crystal display unit displays information; the control unit creates a mask image including a non-irradiation region, which blocks the light output from the light guiding unit, and an irradiation region, which transmits the light output from the light guiding unit, according to a placement location of the subject; when the image pickup unit picks up the first image, the liquid crystal display unit displays the created mask image; the image pickup unit picks up a fourth image when the detection light source is lit and the liquid crystal display unit displays the created mask image; and based on the picked up fourth image, the control unit determines a display darkness of the liquid crystal display unit in the irradiation region included in the created mask image.