JPH0212962Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a visual acuity measurement device in which the electrode structure of a visual acuity test indicator is improved.

[Prior art]

In a conventional visual acuity measuring device, when forming a Landolt ring for a visual acuity test, for example, the segment electrode 1 is used as an indicator for a visual acuity test to form a desired Landolt ring shape having a cut portion, as shown in FIG. 3A. The common electrode 6 forms the outer periphery of the visual acuity test index as shown in FIG. 3B. The rectangular portion 8 has an area that covers the ring portion 2 and the lead line 10. However, the lead line corresponds to a lead line.

The segment electrode 1 and the common electrode 6 are
As shown in FIG. 3C, a rectangular portion 8 of the common electrode 6 is formed on the boundary line between the ring portion 2 forming the outer periphery of the visual acuity test index of the segment electrode 1 and the lead line 4.
Position them so that one side of both electrodes 1,
A visual acuity measuring device was constructed by interposing a liquid crystal between the two.

[Problem that the invention attempts to solve]

Although the conventional visual acuity measuring devices described above are practical for displaying relatively large visual acuity test indicators, they are useful for displaying visual acuity charts and refractometers for desk-top optical visual acuity testing devices such as screenoscopes. In the visual acuity chart used in conjunction with the fixation target of an objective ophthalmoscopy device, the diameter of the Landolt ring used is extremely small, and the positioning accuracy of the segment electrode and common electrode is highly accurate. It becomes necessary.

However, in reality, such highly accurate positioning is difficult, and one side of the rectangular portion 8 may enter the ring portion 2 that forms the outer periphery of the visual acuity test index, causing part of the Landolt ring to be missing. Alternatively, one side of the rectangular portion 8 may be separated from the ring portion 2 forming the outer periphery of the visual acuity test index, creating a protrusion on the Landolt ring.

The purpose of the present invention is to solve the above-mentioned problems of conventional visual acuity measuring devices, and to provide a visual acuity measuring device that can accurately form a highly accurate visual acuity test index even if the positioning accuracy of segment electrodes and common electrodes is loose. There is a particular thing.

〔Example〕

A visual acuity measuring device that displays a Landolt ring, which is a first embodiment of the present invention, will be explained based on FIG.
The segment electrode 20, as shown in FIG. 1A,
It is composed of a ring portion 22 and a lead line 24 that form a part of the outer periphery of the visual acuity test index. As shown in FIG. 1B, the common electrode 6 is approximately rectangular and has an area that covers the ring portion 22 that forms a part of the outer periphery of the visual acuity test index, and also covers the outer periphery of the visual acuity test index. A rectangular portion 30 having a portion 28 that forms a cut portion of the indicator at another portion of the
and a leader line 32.

The lead line 32 is drawn out from other parts of the outer periphery of the visual acuity test indicator other than the part 28 that forms the cut portion of the indicator.

Then, the segment electrode 20 and the common electrode 26
As shown in FIG.
The visual acuity test index is a visual acuity test index. form.

By the way, the above-mentioned electrodes 20 and 26 are formed by vapor-depositing an electrode material in a desired pattern on the surfaces that become the inner surfaces when overlapped, and between the overlapped electrodes, for example, a liquid crystal material abbreviated as MBPA, methoxy benzylidene is applied. - Parabutyl aniline is added, and the overlapping portion 34 of the electrodes 20 and 26 shown by diagonal lines in FIG. 1C becomes dark and displayed when energized.

Next, a second embodiment of the present invention, a visual acuity measurement device that displays an E-letter index, will be described with reference to FIG. As shown in FIG. 2A, the segment electrode 50 is formed by a rectangular portion 52 and a lead line 54, which form a part of the outer periphery of the visual acuity test index. The common electrode 56 is, as shown in FIG. 2B,
It has a part 58 that forms a cut part of the two indicators at another part of the outer periphery of the two visual acuity test indicators,
It is formed by an E-shaped part 60 having an area covering the rectangular part 52 and a lead line 62.

The lead line 62 is drawn out from a part other than the part 58 forming the cut part in another part of the outer periphery of the visual acuity test index.

As shown in FIG. 2C, both electrodes 50 and 56 include a lead line 54 in one of the other parts of the outer periphery of the visual acuity test indicator other than the part 58 that forms the cut part of the indicator. Both electrodes 5 are positioned and overlapped as shown in FIG.
The overlapping portion 70 of 0 and 56 is displayed in a darkened state when energized.

[Effect of idea]

As can be understood from the above embodiments, the present invention has the following features:
A part of the visual acuity test indicator having a cut portion to be displayed includes a first electrode having a shape that has a part forming a part of the outer periphery of the indicator, and another part of the outer periphery of the indicator. a second electrode having a shape that includes the cut portion of the indicator, and a first electrode portion that does not form a part of the outer periphery of the indicator for visual acuity test; Since the leader line is drawn out from the second electrode part that does not include the cut part of the indicator, even if there is some deviation between the two electrodes, the shape of the visual acuity test indicator itself, that is, the visual acuity test function, will not be affected. It does not have a large effect, does not chip part of the visual acuity test index or create protrusions as in conventional methods, and therefore allows for high-precision visual acuity even when the two electrodes are overlapped with relatively loose precision. This has the effect of allowing inspection indicators to be obtained.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a first embodiment of the present invention, FIG. 2 is an explanatory diagram of the configuration of a second embodiment of the invention, and FIG. 3 is an explanatory diagram of the configuration of a conventional visual acuity measuring device. 20, 50... Segment electrode, 22... Ring portion forming part of the outer periphery of the visual acuity test index, 24, 32, 54, 62... Lead line, 2
6, 56... Common electrode, 28... Portion forming the cut portion of the indicator in another part of the outer periphery of the visual acuity testing indicator, 30... Rectangular part, 60... E-shaped part.

Claims (1)

[Claims for Utility Model Registration] A first electrode and a second electrode whose overlapping parts form a visual acuity test index for measuring the visual acuity of a subject, and the cut portion of the index is covered. In a visual acuity measurement device configured to measure visual acuity by being identified by an examiner, a portion of the first electrode forms a portion of the outer periphery of the indicator, and a portion of the second electrode forms a portion of the outer periphery of the indicator. forming another part of the outer periphery of the indicator and including a cut part of the indicator in the other part,
The lead line of the first electrode is drawn out from the first electrode part that does not form a part of the outer periphery of the indicator, and the lead line of the second electrode is drawn out from the cut part in another part of the outer periphery of the indicator. A visual acuity measuring device, characterized in that the indicator is formed by being drawn out from the second electrode portion so as not to include the indicator, and by supplying a current through the lead-out line.