Abstract: A display device includes a substrate, a first display element which is disposed on the substrate, and a plurality of diffraction patterns which are disposed on a path of light emitted from the first display element and arranged along a direction with a first period. when a width of a cross section of one of the plurality of diffraction patterns is defined as a first length, the first period and the first length satisfy Inequality (1): 0.4?d1/DP1?1,??(1) where DP1 is the first period, and d1 is the first length.

Abstract: A chamfering air tool includes a driving shaft in a casing rotated by air pressure, a rotary shaft perpendicularly combined to the driving shaft for rotation, and a cutter fixed to the rotary shaft. Air holes are formed through the rotary shaft in a longitudinal direction. An air discharge groove is formed in the cutter, and a hole communicated with the air hole is formed in a fixing bolt head. An air path is formed in the fixing bolt head to keep a predetermined gap from the cutter. A guide ring having a diameter approximate to a lower end of the cutter is rotatably mounted to the fixing bolt head. Thus, air is blown to the air hole of the rotary shaft, the air hole formed in the fixing bolt head, the air path formed between the cutter and the guide ring, and the air discharge groove of the cutter, thereby eliminating cut chips and cooling the cutter.

Abstract: A chamfering air tool includes a driving shaft rotated by air pressure in a casing, a rotary shaft perpendicularly combined to the driving shaft for rotation, and a cutter fixed to the rotary shaft. Air holes are formed through the rotary shaft in a length direction. Air discharge groove is formed in the cutter. Air hole communicated with the air hole is formed in the fixing bolt head. Air path is formed in the fixing bolt head to keep a predetermined gap from the cutter. Guide ring having a diameter approximate to a lower end of the cutter is rotatably mounted to the fixing bolt head. Thus, air is blown to air hole of the rotary shaft, air hole formed in the fixing bolt head, air path formed between the cutter and the guide ring, and air discharge groove of the cutter, thereby eliminating cut chips and cooling the cutter.