Huvitz Co., Ltd.

Chang Sung Kim

Young Duk Seo

A chart display device for a visual acuity test includes a chart display optical unit that emits a chart image generated by a chart display optical system to a front, and is rotatably coupled to a frame of the chart display device via a rotation shaft; a position indicator light source that indicates the height of an eye to be examined and emits a position identification light; a position detection sensor that detects the position identification light emitted from the position indicator light source, and thus detects the height of the eye to be examined; and a rotation driving unit that rotates the chart display optical unit around the rotation shaft, and thereby tilts an emission direction of the chart image so that the chart image emitted from the chart display optical unit is emitted in the direction of the eye to be examined.

Chart display device for visual acuity tests

An up-and-down driving device allows an up-and-down driving unit to move while supporting an object's load, in a support module in which the up-and-down driving unit is movably inserted into an inner space of a fixed housing. The up-and-down driving device includes: a driving means for moving the up-and-down driving unit in an up-and-down direction; a fixed-position compression spring main module including a fixed-position compression spring having one side fixed to a lower end of the housing and the other side supporting the up-and-down driving unit and mounted in a motion direction of the up-and-down driving unit; and a variable-position compression spring supplemental module including a variable-position compression spring having one side mounted rotatably to a side of the housing and the other side fastened rotatably to the up-and-down driving unit and configured to rotate while making a predetermined angle with the motion direction of the up-and-down driving unit.

Growing community of inventors

Gyeonggi-do, South Korea

Chang Sung Kim