JPS6121045Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a device for projecting a chart for visual acuity testing, and in particular, a device in which the chart is held between two support cylinders from both sides, and is placed on the entire periphery of a rotatable disk. This invention relates to a chart projector for visual acuity testing that projects images using a light source placed at the center of the board.

As a chart projector used for visual acuity testing, there is a chart projector device for optometry, which was filed in Utility Model Application No. 105897/1983 (Application No. 11220/1983), but this is a chart projector device that is used in the vertical direction. The chart is attached to the periphery of a rotatable disk, and it is difficult to attach and remove the chart.
Moreover, there is a risk that the chart may get pinched or damaged, so great care must be taken when handling it. Furthermore, there has been a desire for a device that is easy to detach from the chart and easy to put on in actual use.

Opened in 1977 as another chart projector.
-119827, but it requires a large number of charts to be used for visual acuity testing, and the above-mentioned device that can only accept about 5 charts at a time is not suitable for visual acuity testing. It was inconvenient. That is, in this invention, since the light source was located outside the chart support drum, it was necessary to reduce the chart in order to allow light to pass through, and it was not practical for visual acuity testing.

Generally, with conventional chart projectors, extreme care is required when handling the chart.
And the chart support device (holder) inside the projector
It is mechanically complex, requires a certain amount of skill to attach and detach, and has other drawbacks such as the tendency for finger marks to form on the chart surface.

An object of the present invention is to provide a new chart projector for visual acuity test charts that eliminates the drawbacks of the prior art. If you attach it by holding both sides of the chart holder,
Anyone can handle it easily and with peace of mind without worrying about leaving finger marks.

The present invention will be described in detail below based on embodiments shown in the drawings.

FIG. 1 is a plan view of the chart projector, and FIG. 2 is a sectional view taken along line AA in FIG. The chart projector 10 consists of a horizontally installed disc 1, a chart 3, a chart support cylinder 2, a light source 4, a projection lens 11, and other lens groups 12.
The chart support columns 2 are installed on the outer peripheral edge of the disk at equal intervals (at equal angles) and perpendicular to the plane of the disk. This interval corresponds to the width of the chaat used in this invention, and in this invention, 15 supporting columns are arranged, so 15 chaats can be held between the pillars at once. be done. Chart 3 is a chart 3 of a glass plate covered with a glass plate with the necessary drawings painted in black or white.
1 and a chart holder frame 32, and locking recesses 33 are provided on both side walls of the chart holder to fit and connect with the support column 2 in the vertical direction, and can be attached to the chart holder as necessary. Holding the frame portion 32 of the holder, a cheer can be mounted between two supporting columns from vertically above the supporting columns. Fifteen charts are vertically erected at each interval between support columns 2, and the disk 1 is rotated by a drive device (not shown) while keeping the center of rotation about the center 5 where the light source 4 is placed, while maintaining the horizontal position. As the disc rotates, the chart sequentially moves to lens groups 11 and 12.
The projector is placed in front of the projector and is ready for projection.

The light source 4 uses a halogen lamp and emits a strong light source, so it is housed in a box for the light source and is formed to prevent the light source from leaking in directions other than the lens group. Since the distance between the light source and the chart is relatively short, the image introduced into the projection lens is clear and inspection accuracy can be improved.

Since the present invention has the structure described in detail above, anyone can easily attach and remove the chart holder, and it also makes it easier to handle charts, which conventionally required extreme care, and it is possible to handle a large number of charts at once. It has the great practical advantage of being able to be set to

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the entire invention.
FIG. 2 is a sectional view taken along the line AA in FIG. 1. 1: Disc, 2: Chart holder support cylinder,
3: chart holder, 4: light source, 10: chart holder, 31: chart, 32: chart holder frame, 33: locking recess.

Claims (1)

[Scope of utility model registration request] In a chart projector in which a large number of charts for visual acuity testing are arranged and the charts are projected using a projection optical system, a horizontally arranged rotatable disk 1 is used.
Thin cylindrical chart holder supports 2 are mounted on the peripheral edge of the disc 1 at equal intervals, and a visual acuity test chart 3 is fitted between the supports, and light is emitted from a light source 4 installed at the center of the disc 1. A chart projector for visual acuity testing that projects a chart using light.