A display device for displaying image information to a user, comprising: an image generator , configured to output an output image ; and a photo-switchable screen , configured to generate the image information according to the output image , the photo-switchable screen having a first light-transmittance in a first area of the photo-switchable screen in a first operation mode and having a second light-transmittance in the first area of the photo-switchable screen in a second operation mode, said first light-transmittance being less than the second light-transmittance; characterized in that in a first light-emitting period , the image generator outputs the output image to the first area and the first area of the photo-switchable screen is operated in the first operation mode, in a first non-light-emitting period , the image generator stops outputting the output image and the first area of the photo-switchable screen is maintained in the first operation mode, in a second light-emitting period , the image generator outputs the output image to the first area and the first area of the photo-switchable screen is maintained in the first operation mode, in a second non-light-emitting period , the image generator stops outputting the output image to the first area and the photo-switchable screen operates in the second operation mode, in a third light-emitting period , the image generator outputs the output image to the first area and the photo-switchable screen operates in the second operation mode, and in a third non-light-emitting period , the image generator stops outputting the output image and the photo-switchable screen operates in the second operation mode. an image generator , configured to output an output image ; and a photo-switchable screen , configured to generate the image information according to the output image , the photo-switchable screen having a first light-transmittance in a first area of the photo-switchable screen in a first operation mode and having a second light-transmittance in the first area of the photo-switchable screen in a second operation mode, said first light-transmittance being less than the second light-transmittance; characterized in that in a first light-emitting period , the image generator outputs the output image to the first area and the first area of the photo-switchable screen is operated in the first operation mode, in a first non-light-emitting period , the image generator stops outputting the output image and the first area of the photo-switchable screen is maintained in the first operation mode, in a second light-emitting period , the image generator outputs the output image to the first area and the first area of the photo-switchable screen is maintained in the first operation mode, in a second non-light-emitting period , the image generator stops outputting the output image to the first area and the photo-switchable screen operates in the second operation mode, in a third light-emitting period , the image generator outputs the output image to the first area and the photo-switchable screen operates in the second operation mode, and in a third non-light-emitting period , the image generator stops outputting the output image and the photo-switchable screen operates in the second operation mode. <EOS>