JPS6352893B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an eyeball refractive power measuring device.

Conventional technology A known measuring device used to objectively measure the refractive power of the eyeball emits infrared light converged into a beam in a pulsed manner at a high frequency and irradiates the eyeball with a high-frequency pulse. The image formed by using the light spot obtained in the above as a secondary light source is applied to a photodetector, and the refractive power is calculated based on the difference in the position on the photodetector.

However, with such a measuring device, it is necessary to irradiate the infrared light from the front of the eyeball so that the reciprocating infrared light is not blocked by the erythema. In addition, when taking measurements using the above device, it is necessary to fix the eyeballs, so measurements must be taken while looking through a thin peephole. This makes it easy for people to become temporarily nearsighted due to movements such as looking into objects, so-called mechanical nearsightedness, and it is not possible to perform correct measurements in a natural state.

Problems to be Solved by the Invention The technical problem to be solved by the present invention is to create an optical system that eliminates the need for the above-mentioned unnatural movements such as looking into the eyes, and that allows correct measurement even when the eyeballs are moved. An object of the present invention is to provide an eyeball refractive power measuring device having the following characteristics.

Means for Solving the Problems In order to solve the above-mentioned technical problems, the eyeball refractive power measuring device according to the present invention modulates infrared light focused in a beam shape with a high frequency and emits it in a pulse shape. A light projecting/receiving measuring device that receives reflected light from the fundus of the subject's eye and measures the refractive power of the eyeball, and a plane reflector that can give a slight rotation in two axes to the reflective surface that reflects the infrared light by a drive unit. and a bifocal focusing device comprising an elliptical mirror that has one focal point located at the center of rotation on the flat reflecting mirror and reflects the reflected light from the reflecting mirror to focus it on the other focal point; An infrared light reflector that reflects the infrared light from the bifocal focusing device and focuses it on the subject's eyeballs, but transmits visible light, and a drive unit for the flat reflector that captures the movement of the eyeballs. The eye movement detection device provides feedback for irradiating infrared light from the front of the eyeball.

In the real-time eyeball refractive power measuring device of the present invention having the above-described configuration, the beam-shaped infrared light from the light emitting/receiving light measuring device is reflected on a two-axis rotatable plane reflector, and then reflected between two focal points. The light beam is reflected by the elliptical mirror of the focusing device, but since one focal point of the elliptical mirror is located at the center of rotation of the flat reflecting mirror, the light beam reflected by the elliptical mirror is always reflected at the other focal point of the bifocal focusing device. The light beam that gathers at this focal point is reflected by an infrared light reflector, the center of the eyeball is set at the reflected focal position, and the movement of the eyeball is tracked by an eyeball movement detection device. By feeding this signal back to the two-axis swing mechanism of the plane reflector and controlling the direction of the plane reflector in accordance with the movement of the eyeball, the light beam is irradiated from the front of the eyeball regardless of the movement of the eyeball. be able to.

In addition, the infrared light reflector reflects only infrared light,
Since it allows visible light to pass through, the test subject can perform measurements while looking at the work environment etc. through this reflector in a natural state.

Effects According to the eye refractive power measuring device of the present invention, it is not only possible to perform accurate measurements while the subject is looking at the working environment in a natural manner, but also to ensure that even if the subject makes eye movements during the measurement, The irradiation direction of the light beam can be adjusted according to the movement of the eyeball, so that the eyeball can always be irradiated with the light beam from the front.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In Fig. 1, reference numeral 1 denotes an infrared light projection/reception measurement device that modulates infrared light with high frequency, converges it into a beam, and emits it, and also receives reflected light from a light spot on the fundus of the eye and determines its position. It has a function of detecting the refractive power of the eyeball and measuring the refractive power of the eyeball by calculation in the data processing section. The plane reflecting mirror 2 disposed opposite to the above-mentioned light emitting/receiving measuring device 1 is supported by a flexible support plate 3 so as to be able to rotate slightly on two axes around the central portion 2a of the reflecting mirror 2, and has a two-axis swinging mechanism. 2 by the swing arm of 4
It is designed to give rotational motion in the axial direction, and the light reflected by this plane reflecting mirror 2 is reflected by the two-axis swinging mechanism 4.
The beam is scanned at a high frequency, the scanning range is successively changed, and the beam is projected onto the elliptical mirror 5a of the bifocal focusing device 5.

The bifocal focusing device 5 includes elliptical mirrors 5a and 5b.
, one focal point of the elliptical mirror 5a is located at the central rotation center 2a of the plane reflecting mirror 2, and
The other focal point is focused on a common focal point 6 with the other elliptical mirror 5b, and the other focal point 7 of the elliptical mirror 5b is focused on a single point in space.
is focused to its mirror image position by an infrared light reflecting plate 8, thereby positioning the focal point 7 substantially at the center of the eyeball 9a of the subject 9. Above 2
The interfocal focusing device 5 may use a single elliptical mirror, but in this case, the size of the real image focused on other focal points changes depending on the irradiation direction of the light beam. It is effective to provide elliptical mirrors 5a and 5b having the same optical characteristics at symmetrical positions to form a real image with the same magnification. The infrared light reflecting plate 8 reflects infrared light but transmits visible light.

As the eyeball movement detection device 10 that detects the eyeball movement of the subject 9, a known detection device that detects the eyeball movement based on the position of reflected light on the cornea of infrared light projected onto the eyeball, for example, can be used. The output of the eyeball movement detection device 10 is output to the two-axis swinging mechanism 4, which is a drive section of the flat reflector 2, and gives the flat reflector 2 a rotational motion corresponding to the eyeball movement.

Furthermore, since it is necessary to set the center of the eyeball to be on the single focal point of the elliptical mirror 5b, it is effective to attach a means for monitoring this to the eyeball movement detection device 10 as shown in the figure. be.

The illustrated eye movement detection device 10 is designed to also function as a monitor television, so that when making settings while monitoring, it is better to monitor while aligning the standard direction of the measurement beam with the optical axis. Since the setting is easy, a half mirror 11 is provided to align the optical axes. Also,
The eye movement detection device 10 is configured to be able to measure (x, y) coordinates of a high brightness point in a television image in real time in order to have an eye movement detection function as well as a function as a monitor television. The two-axis swing mechanism 4 is driven by the output of the lever, and is controlled so that the measurement beam always points in the viewing direction. The above-mentioned high brightness points include, for example, the infrared light emitting source 12
A virtual image created by reflection on the corneal surface of the eyeball can be used. The eye movement detection device 10 is used for movement detection because the position of a virtual image formed by reflection on the corneal surface changes depending on the eye movement. In order to distinguish the virtual image of the infrared light emitting source from the virtual image created by the measurement infrared light, time-division blinking may be performed and points synchronized with this blinking may be detected.

In the figure, reference numeral 13 indicates the subject's working environment, for example, an information input/output device, which is seen through the infrared light reflecting plate 8.

In the eyeball refractive power measuring device having the above configuration, first, a beam-shaped infrared light modulated with a high frequency is projected from the light emitting/receiving measuring device 1 onto the eyeball 9a of the subject 9. The light is once reflected by the mirror 2, and the reflected light is further reflected by the elliptical mirror 5a of the bifocal focusing device 5. At this time, the elliptical mirror 5
Since the first focus of a is located, this rotation center 2
When a light beam is irradiated onto the elliptical mirror 5a, the light beam reflected by the elliptical mirror 5a always converges on the other focal point, that is, on the common focal point 6 with the elliptical mirror 5b. Furthermore, in the elliptical mirror 5b, the light beam from the common focal point 6 is focused onto the other focal point 7. Therefore, before the light beam converges on this focal point 7, it is reflected again by an infrared light reflector 8 that reflects only infrared light, and the center of the eyeball 9a is set at the focal position after reflection.
A light beam is always directed at the eyeball.

In other words, even if the angle of the biaxially rotatable plane reflector 2 on which the light beam is reflected is changed, the light beam will follow other reflection paths in the bifocal focusing device and will ultimately converge at the same focal position. It turns out. In this way, the bifocal focusing device 5 takes advantage of the property that light emitted from one focal point of an elliptical mirror always forms an image on the other focal point, and has a structure that irradiates the same point from various directions. By placing the center of the eyeball at this focal point, even if the direction of the eyeball changes due to the subject's eyeball movement, just by slightly rotating the two-axis rotatable plane reflector 2, It becomes possible to always irradiate the infrared light beam from the front of the eyeball.

Therefore, the movement of the eyeball is tracked by the eyeball movement detection device 10 placed opposite to the eyeball, and this signal is fed back to the two-axis swinging mechanism 4 of the plane reflector 2. The direction is controlled so that the light beam is irradiated from the front of the eyeball in accordance with the movement of the eyeball, so that accurate measurements can always be performed regardless of the movement of the eyeball.

In addition, the infrared light reflector 8 that reflects the light beam just before it enters the eyeball reflects only the infrared light and transmits visible light, so the subject can view the work environment 13 and the subject as appropriate through this reflector 8. This allows measurements to be taken naturally and in real time even during work.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of an eyeball refractive power measuring device according to the present invention. 1... Light emitting/receiving measuring device, 2... Plane reflecting mirror, 2
a... Center of rotation, 5... Bifocal focusing device, 5
a, 5b... Elliptical mirror, 6, 7... Focal point, 8... Infrared reflector, 9... Subject, 9a... Eyeball, 10
...Eye movement detection device.

Claims (1)

[Claims] 1. A light emitting/receiving measuring device that modulates infrared light converged in a beam shape with a high frequency and emits it in a pulse shape, and measures the refractive power of the eyeball by receiving reflected light from the fundus of the subject's eye, and the infrared light as described above. A plane reflecting mirror that can give a slight rotation in two axial directions to a reflecting surface that reflects light by a drive unit, and one focal point is positioned at the center of rotation on the plane reflecting mirror, and the reflected light from the reflecting mirror is reflected. A bifocal focusing device is equipped with an elliptical mirror that focuses the light onto the other focal point, and the infrared light from the bifocal focusing device is reflected and focused onto the subject's eyeball, but visible light is transmitted. and an eye movement detection device that captures the movement of the eyeball and provides feedback so that the drive unit of the plane reflector always irradiates infrared light from the front of the eyeball. Eye refractive power measuring device.