KR100537013B1 - ophthalmic chart project - Google Patents

Abstract

A chart projector incorporating a spare lamp is disclosed. The chart projector including a projection optical system for forming a chart image projected by a predetermined light beam irradiated to the chart includes: a first housing 13 provided with a condenser lens 16 of the projection optical system; A fourth housing 25 mounted in the first housing 13 and adapted to move in a predetermined direction; Two or more lamps 11 and 23 fixed in the fourth housing 25 and arranged in a predetermined direction; A handle 24 for moving the fourth housing 25 in a predetermined direction; A sensor plate 22 attached to an outer end of the fourth housing 25 to move together when the fourth housing 25 is moved by a handle 24; And switching means (21) attached to an outer end of the first housing (13) and determining power supply to any one of the two or more lamps (11, 23) in conjunction with the sensor plate (22). A positioning ball plunger 27 is provided in the housing 13, and a fastening groove 26 corresponding to the ball plunger 27 is formed in the fourth housing 25.

Description

Chart projector {ophthalmic chart project}

The present invention relates to a chart projector. More particularly, the present invention relates to a chart projector for visual acuity measurement that facilitates replacement of a spare lamp by a user by incorporating a spare lamp.

A method of measuring the visual acuity of a subject, by placing a chart printed with letters or graphics of various sizes at a distance from the subject, and checking whether the subject can identify the printed text or graphics on the chart. The method is widely used. However, charts in which such letters and figures are printed directly should be made large enough to be identified by the examinee, and it is difficult not only to replace the chart image and to move the chart, but also to use unnecessary space even when the vision measurement is not performed. The disadvantage is that it occupies. Therefore, in recent years, a chart projector in which an image of a character or a figure is formed, and a chart having a small size having light transmittance is prepared, and light is irradiated from the back of the chart to enlarge the image formed on the chart on the screen. Mainly used. In addition, the examinee may examine the vision by identifying the chart image enlarged on the screen.

1 shows the structure of a conventional chart projector. The chart projector is disposed on the lamp 11 installed in the first housing 13, the rear reflector 12 disposed at the rear of the lamp 11 in the first housing 13, and the front of the lamp 11. The light collecting lens 16 for condensing the light generated by the lamp 11 into a light having a constant size and uniform intensity, is installed in the second housing 17 coupled to the first housing 13, a predetermined pattern is formed Chart 18, which is installed in a third housing 19 coupled with the second housing 17, and consists of a projection lens 20 that sends a chart image from the chart 18 onto an external screen (not shown). have. The lamp 11 is fixed to the first housing 13 by using a fixing plate 15 provided at an upper end thereof, a fixing plate 15, and a screw 14 penetrating through the first housing 13. .

In order to replace the lamp 11 at the end of the life of the lamp 11, loosen the screw 14, remove the fixing plate 15 and take out the lamp 11. Then, the new lamp is placed in the corresponding position, and the fixing plate 15 is placed and the screws 14 are fixed to fix the new lamp in the first housing 13, which is very troublesome and does not provide convenience of use. In addition, when the lamp is turned off during the inspection, the inspection must be performed again after replacing the lamp, causing inconvenience such as an increase in the time required for the inspection.

Accordingly, an object of the present invention is to provide a chart projector that can provide ease of use by reducing the number of opening and closing of the chart projector for lamp replacement.

Another object of the present invention is to provide a chart projector capable of minimizing inspection time by performing an inspection process by easily replacing the lamp with a spare lamp even when the power of the lamp is turned off during the inspection.

In order to achieve the above object, a chart projector including a projection optical system for forming a chart image projected by a predetermined light beam irradiated to a chart is provided with a first housing 13 in which a condenser lens 16 of the projection optical system is installed. A fourth housing 25 mounted in the first housing 13 and adapted to move in a predetermined direction; Two or more lamps 11 and 23 fixed in the fourth housing 25 and arranged in the predetermined direction: means 24 and a fourth housing for moving the fourth housing 25 in the predetermined direction. A sensor plate 22 attached to the outer end of the 25 and moving together when the fourth housing 25 is moved by the moving means 24; And a switching means 21 attached to an outer end of the first housing 13 and determining power supply to any one of the two or more lamps 11 and 23 in cooperation with the sensor plate 22. A positioning ball plunger 27 is provided in the first housing 13, and a fastening groove 26 corresponding to the ball plunger 27 is formed in the fourth housing 25, so that the fourth housing 25 is provided. When any one of the two or more lamps fixed in the fourth housing 25 by the movement of is positioned in line with the condenser lens 16 in the first housing 13, the fourth in the first housing 13. The position of the housing 25 is fixed.

delete

delete

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. For convenience of description, the same reference numerals are given to members that perform the same functions as in the prior art.

2 is a cross-sectional view of a chart projector for measuring eyesight according to an example of the present invention, and FIG. 3 is a front view of FIG. 2.

2 and 3, the chart projector according to an embodiment of the present invention is the first housing 13, the fourth housing 25, the fourth housing (25) which is inserted and moved up and down in the first housing ( 25, the lamp 11 and the spare lamp 23 fixed to the top and the bottom in the first housing 13, and the rear reflector 12 and the lamp ( 11 is disposed in front of the condenser lens 16 for condensing the light generated from the lamp 11 into light having a constant size and uniform intensity, in the second housing 17 coupled with the first housing 13. Installed in the chart 18, the third housing 19 is coupled to the second housing 17, the predetermined pattern is formed, and sends the chart image from the chart 18 to an external screen (not shown) It consists of a projection lens 20.

The first housing 13 has a ball formed on the front surface thereof, and a ball plunger 27 having a spring is provided therein, and the fourth housing 25 has a ball plunger 27 at a position corresponding to the straight line. The groove 26 is formed so that the fourth housing 25 is fixed to the first housing 13. When the position is fixed by the ball plunger 27 and the groove 26, the spare lamp 23 is positioned between the rear reflector 12 and the condenser lens 16.

A handle 24 for moving the fourth housing 25 is attached to a lower end of the fourth housing 25, a sensor plate 22 is provided on an upper side of the fourth housing 25, and a first housing The photointerrupter 21 which cooperates with the sensor plate 22 is attached to the upper side surface of 13. The sensor plate 22 and the photo interrupter 21 interoperate with each other to switch a power signal for turning on the lamp 11 or the spare lamp 25 and constitute an element for switching the power signal. Various other modifications are possible as far as possible.

As shown in Figure 2, the state using the lamp 11, the rear reflector 12 in the rear, the condenser lens 16 in the front centering on the lamp 11 installed at the top in the fourth housing 25 The projection lens 20 forms an optical system. At this time, the position of the sensor plate 22 sensed by the photo interrupter 21 is set as the reference position, and the power supply circuit (not shown) is designed to supply power to the lamp 11 at the 'reference position'. have.

However, when the life of the lamp 11 is reached, the handle 24 attached to the lower end of the fourth housing 25 is lifted up. The fourth housing 25 is moved upward in the first housing 13 so that the spare lamp 23 is positioned at the portion where the lamp 11 is positioned by using the handle 24. At this time, the position fixing of the fourth housing 25 or the spare lamp 23 is performed by inserting the ball plunger 27 provided in the first housing 13 into the groove 26 provided in the fourth housing 25. And along with the upper movement of the 4th housing 25, the sensor plate 22 attached to the upper end of the 4th housing 25 also moves together, and the photo provided in the upper end side surface of the 1st housing 13 was carried out. The interrupter 21 recognizes that the sensor plate 22 is out of the 'reference position' so that the photo interrupter 21 switches the power supply circuit from the connection with the lamp 11 to the connection with the spare lamp 23. do. Accordingly, power is supplied to the spare lamp 23 so that the rear reflector 12, the spare lamp 23, the condenser lens 16, and the projection lens 20 form an optical system of the chart projector, The lamp for chart projection can be easily operated without opening the cover, and the time required for vision measurement can be minimized.

Meanwhile, in the description of the present invention, the lamp 11 and the spare lamp 23 are disposed up and down in the fourth housing 25, and the fourth housing 25 is moved up and down in the first housing 13. Although one structure has been described by way of example, the spirit of the present invention is not limited thereto.

For example, the fourth housing 25 moves left and right within the first housing 13, the lamp 11 is fixed to one side of the fourth housing 25, and the spare lamp 23 is fixed to the other side thereof. In addition, the spare lamp 23 is a rear reflector (by the left and right movements of the ball plunger 27 and the grooves 26 formed in the fourth housing 25 and the fourth housing 25 provided in the first housing 13). 12) When positioned in the front, if configured to be fastened, after the life of the lamp 11, the spare lamp 23 built in the device can be used as a light source of the projection optical system without opening the cover of the device.

In addition, the fourth housing 25 is configured to have a cylindrical shape, and the fourth housing 25 is changed to move in a shape of a 'arc' of a circle centered on the outside of the first housing within the first housing 13. When the lamp 11 and the spare lamp 23 are installed at predetermined intervals along the arc in the fourth housing, the built-in spare lamp can be used as a light source of the projection optical system without opening the cover of the device.

 In addition, in the exemplary embodiment of the present invention, only one spare lamp is installed in the fourth housing in addition to the lamp. However, the present invention is not limited thereto, and two or more spare lamps may be installed in consideration of the size and volume of the chart projector.

As described above, the chart projector according to the present invention has a built-in spare lamp in addition to the lamp for providing a light source constituting the projection optical system, and the spare lamp can be replaced by a simple operation, the chart for lamp replacement The user's convenience is reduced by reducing the number of openings of the projector, and the time required for the vision measurement can be minimized when the lamp is replaced during the vision measurement.

1 is a schematic view for explaining the structure of a conventional chart projector.

2 is a schematic diagram illustrating a structure of a chart projector according to an exemplary embodiment of the present invention.

3 shows a front view of the chart projector disclosed in FIG. 2.

Claims (7)

A chart projector comprising a projection optical system for forming a chart image projected by a predetermined light beam irradiated to a chart, the chart projector comprising: A first housing 13 on which the condenser lens 16 of the projection optical system is installed; A fourth housing 25 mounted in the first housing 13 and adapted to move in a predetermined direction; Two or more lamps 11 and 23 fixed in the fourth housing 25 and arranged in the predetermined direction; Means (24) for moving said fourth housing (25) in said predetermined direction; A sensor plate 22 attached to an outer end of the fourth housing 25 to move together when the fourth housing 25 is moved by the moving means 24; And A switching means 21 attached to an outer end of the first housing 13 to determine power supply to any one of the two or more lamps 11 and 23 in cooperation with the sensor plate 22, The first housing 13 is provided with a positioning ball plunger 27, and the fourth housing 25 is provided with a fastening groove 26 corresponding to the ball plunger 27. The first housing, when any one of the two or more lamps fixed in the fourth housing 25 by movement of 25 is located in line with the condenser lens 16 in the first housing 13 A chart projector for fixing the position of the fourth housing (25) to (13). delete delete The method of claim 1, wherein the fourth housing is moved up and down in the first housing, some of the two or more lamps are attached to the top in the fourth housing and the rest of the two or more lamps are 4 Chart projector, characterized in that attached to the bottom in the housing. The method of claim 1, wherein the fourth housing is moved in the left and right direction within the first housing, some of the two or more lamps are attached to the left end in the fourth housing and the rest of the two or more lamps are Chart projector, characterized in that attached to the right end in the fourth housing. The method of claim 1, wherein the fourth housing is cylindrical, the fourth housing moves along an arc about an axis of the cylinder within the first housing, and some of the two or more lamps are located on one side of the arc. And wherein the remainder of the two or more lamps is attached to the other side of the arc. A chart projector comprising a projection optical system for forming a chart image projected by a predetermined light beam irradiated to a chart, the chart projector comprising: A first housing 13 on which the condenser lens 16 of the projection optical system is installed; A fourth housing 25 mounted in the first housing 13 and adapted to move in a predetermined direction; Two or more lamps 11 and 23 fixed in the fourth housing 25 and arranged in the predetermined direction; Means (24) for moving said fourth housing (25) in said predetermined direction; A sensor plate 22 attached to an outer end of the fourth housing 25 to move together when the fourth housing 25 is moved by the moving means 24; And And a photo interrupter 21 attached to an outer end of the first housing 13 to determine power supply to any one of the two or more lamps 11 and 23 in cooperation with the sensor plate 22, Any one of the two or more lamps fixed in the fourth housing 25 by the movement of the fourth housing 25 is positioned in line with the condensing lens 16 in the first housing 13. Chart projector.