Visual acuity examination apparatus
AssigneeNeitz Instruments Co., Ltd.
InventorsSanyo Nagayama, Natsuki Munekata
Life of this patent
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Abstract
A visual acuity examination apparatus is provided with a mark display face which has an outer face on which at least one mark is displayed so as to be viewed and which is formed such that the at least one mark and the periphery thereof are illuminated with a predetermined brightness, and a light shielding face which is disposed in front of the display face to be subjected to high speed movement, which is formed with a slit having a proper width and whose front face is formed so as to be illuminated with the same brightness as that of the mark display face. Accordingly, an accurate display contrast of the mark can be realized with a simple structure and without deterioration with age.
Claims10
A visual acuity apparatus to test the visual acuity of a person looking in a visual direction;
- the apparatus comprising:
- a mark display face which includes an outer face on which at least one mark is displayed so as to be viewed along the visual direction and wherein the at least one mark and a periphery of the outer face of the mark display face are illuminated with a predetermined brightness;
- and
- a light shielding face which is disposed in front of the display face to be moved at a high speed, the light shielding face comprising a slit having a proper width, wherein the front face is illuminated with the same brightness as that of the mark display face;
- and
- wherein the mark display face and the light shielding face are relatively offset along the visual direction.
Dependencies are inferred from the claim text.