JPH0651021B2 - Eye imager - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an eye imaging device that captures a fundus image of an eye to be inspected.

[Prior Art] A fundus camera for inspecting and photographing the fundus has become indispensable for ophthalmic diagnosis. For example, this fundus camera is used for circulatory system examination by fluorescence angiography, diagnosis of intraocular retina, diagnosis of vascular disorders in urology, diagnosis of retinal detachment, etc., but in all cases also vascular structure is diagnosed. There are difficulties in obtaining a possible image.

However, for diagnostic reasons, it is desired to obtain a fundus image having better resolution and contrast in a direction in which the burden on the patient is minimized. An attempt to do this is described in US Pat. No. 4,213,678. FIG. 2 shows the known device, which is emitted from the laser light source 1 and is horizontally moved by the galvano mirrors 2a and 2b.
The vertically polarized laser beam is reflected by the mirror 3 and the lens 4.
The fundus Er of the eye E to be inspected is continuously scanned in the form of a linear raster via the above. Also, the laser beam reflected by the fundus Er is
The light is received by the light receiving element 6 by the lens 5 and the like via the pupil Ep and becomes an electric signal. By synchronizing this signal with the scanning signal, the fundus image is displayed on the television monitor.

Further, as another eye image device, Japanese Patent Laid-Open No. 59-11502.
Japanese Unexamined Patent Publication No. 4 (1999) describes that an electronic shutter is used to partially pass the laser beam and the signal is increased only when the laser beam passes to reconstruct the screen. However, improvement in resolution cannot be expected by such a method.

[Object of the Invention] An object of the present invention is to provide an eye image device capable of zooming and obtaining an image with high resolution in a magnified image.

[Summary of the Invention] An eye imaging apparatus according to a first aspect of the invention for achieving the above object is a scanning optical system that scans a light beam on a region of a subject eye to be imaged, and a light receiving unit that receives the light beam from the region. In a device having a means and a display means for displaying an image of the eye to be inspected based on a signal from the light receiving means, a means for changing the magnification of the image of the eye to be inspected on the image output unit, and a magnification of the image of the eye to be inspected It is characterized by comprising means for changing the beam diameter of the scanning light beam in accordance with the change.

An eye imaging apparatus according to a second aspect of the invention is based on a scanning optical system that scans a light beam on a region of an eye to be imaged, a light receiving unit that receives the light beam from the region, and a signal from the light receiving unit. And a display unit for displaying an image of the eye to be inspected. The apparatus is provided with a unit for changing a scanning density of scanning on a region to be imaged by the scanning optical system.

Embodiments of the Invention The present invention will be described in detail based on the embodiment shown in FIG.

FIG. 1 shows an embodiment according to the present invention, in which a light flux L emitted from a laser head 12 to which a laser controller 10 and a laser light source 11 are connected is a light flux expander 13 and an acousto-optic deflector (hereinafter referred to as AOD). 14, imaging lens 1
5, a relay lens 17 having a vertical scanning galvanometer mirror 16 in the middle, a field lens 18, a mirror 19, a variable power relay lens 20, a perforated mirror 21, and an objective lens 22.
To reach the eye E to be inspected. Further, on the reflection side of the light flux from the direction of the objective lens 22 of the perforated mirror 21, a relay lens 24 having a small black dot 23 in the middle,
The small light shield 25, the ring slit 26, the small light shield 27, the mirror 28, the condenser lens 29, and the light receiving element 30 are sequentially arranged.

40 is an electric controller, AOD driver 4
Galvanometer mirror driver 42 to AOD 14 via 1
A control signal is sent to the galvano mirror 16 via the, and the signal is sent from the light receiving element 30 to the controller 40 via the amplifier 43. Further, the controller 40
From the image signal is transmitted to the television monitor 44.

First, the observation method using the laser beam L will be described.
The laser beam L emitted from the laser head 12 is incident on the beam expander 13 after being aligned with the aperture of the AOD 14. The AOD 14 deflects the laser light flux L at high speed, that is, continuously sweeps it, as indicated by L1 to L1 ', by the signal of the AOD driver 41. In reality, this deflection is perpendicular to the plane of the drawing, but is shown parallel to the drawing in the drawing. The laser light flux L deflected by the AOD 14 is moved by the imaging lens 15.
A one-dimensional dot array is formed on S1, and these dot arrays form a linear raster on the first scanning surface S2 by the vertical scanning galvanometer mirror 16 and the relay lens 17. At this time, the galvanometer mirror 16 is driven by the galvanometer mirror driver 42, and the input signal to the AOD driver 41 and the input signal to the galvanometer mirror driver 42 are input to the controller 4.
0 is synchronized.

The scanning surface S2 corresponds to the film surface of the fundus camera, and the second scanning surface via the mirror 19 by the variable power relay lens 20.
It is conjugated with S3, and the magnification of the variable power relay lens 20 is varied to make the relay magnification variable. Furthermore, S3
Is made conjugate with the fundus Er of the eye E by the optical system of the objective lens 22 and the eye E to be inspected.
The linear raster of S2 can scan the fundus Er of the eye E with different magnifications by the action of the variable power relay lens 20. On the other hand, the laser light flux L reflected by the fundus Er passes through the pupil Ep of the eye E to be examined and the objective lens 22 common to the scanning optical system.
After that, the light is reflected downward by the perforated mirror 21 arranged at the conjugate point P1 of the pupil Ep by the objective lens 22, and is condensed on the light receiving surface P3 of the light receiving element 30 by the relay lens 24, the mirror 28, and the condenser lens 29. .

Here, the pupils Ep, P1, P2, and P3 are each optically conjugate, and the ring slit 26 that forms an image in the hole of the perforated mirror 21 is arranged in P2, and the scanning optical system and the light receiving optical system are arranged. Is coupled in the form of pupil division, similar to the conventional fundus camera. Further, in the relay lens 24, small black dots 23 for removing reflected light from each surface of the objective lens 22,
Small light shields 25 and 27 that cut reflected light and scattered light from the cornea of the subject's eye E before and after P2 and points substantially conjugate to the crystalline lens position are arranged.

In this way, the light receiving element 30 can receive only the reflected light from the fundus Er from which various harmful reflected and scattered lights are cut. The output of the light receiving element 30 is input to the controller 40 via the amplifier 43, and then the controller 40
From AOD driver 41, Galvano mirror driver 42
It is emitted toward. A constant sync signal is always combined with the variable magnification, and a standard television signal is output to the television monitor 44. The television monitor 44 receives the signal from the controller 40 and displays the fundus image Er '. Furthermore, all the constituent elements within the broken line are stored in the same housing,
It is possible to align the front, back, left, right, and up and down with respect to the eye E to be examined. That is, since the optically coupled components are integrally formed, no special consideration is required for alignment.

Consider a case where zooming is performed in the embodiment of the present invention configured as described above. As described above, the scanning optical system maps the first scanning surface S2 to the eye to be examined Er at different magnifications by the action of the variable power relay lens 20. Here, the first scanning plane S2
The resolution of the linear raster formed on the fundus Er of the eye E to be examined, that is, the total number of pixels resolved in the screen, if the subsequent optical system is not affected and the aberration of the optical system is sufficiently corrected. Is the same as the resolution on the first scanning surface S2 regardless of the mapping magnification. This is reasonable considering that the observation is performed on the same television monitor 44 regardless of the magnification. Then, the resolution is substantially determined by the size of the aperture of the AOD 14 and the galvano mirror 16 and the screen size on the first scanning surface S2. In other words, the performance of the scanning device including the AOD 14 and the galvano mirror 16 is always sufficiently exhibited even when the observation magnification is changed. This is extremely important in view of the fact that the resolution of the AOD 14 is slightly inferior to that of a polygon mirror system, etc., as described above, and it is an essential condition for providing sufficient resolution even when magnified observation is performed. It can be said that there is.

With the above-described unique configuration of the present invention, a high-speed scanning system based on the AOD 14 can be adopted, and by extension, all optical systems from the laser head 12 to the light receiving element 30 can be integrally combined. That is, since a high-speed scanning system using a polygon mirror is very large and heavy, if it is forcibly combined with all the optical systems, inertia will be large when the optical system is aligned with the eye E to be inspected. , Because delicate alignment becomes impossible.

It should be noted that when the pupil position is significantly moved by the variable power relay lens 20, it is preferable that the field lens 18 be taken in and out as necessary.

[Effects of the Invention] As described above, in the eye imaging device according to the present invention,
Particularly, in the first invention, the beam diameter of the scanning light beam is changed in accordance with the change of the multiplication factor of the eye to be inspected, so that a high-definition image can be obtained when the image is enlarged, and the scanning density is changed in the second invention. By providing the means for increasing the scanning density at the time of image enlargement so that a high-definition image can be obtained, a high resolution can be obtained by magnifying observation.

[Brief description of drawings]

Drawing FIG. 1 is a block diagram of an embodiment of an eye image device according to the present invention, and FIG. 2 is a block diagram of a conventional device. Reference numeral 11 is a laser light source, 12 is a laser head, and 14
Is an AOD, 16 is a galvanometer mirror, 20 is a variable magnification relay lens, 21 is a perforated mirror, 22 is an objective lens, 30 is a light receiving element, 40 is a controller, and 44 is a television monitor.

Claims (2)

[Claims] 1. A scanning optical system for scanning a light beam on a region of an eye to be imaged, a light receiving unit for receiving the light beam from the region, and an image of an eye to be inspected based on a signal from the light receiving unit. An apparatus having a display means, comprising means for changing the magnification of the eye image on the image output unit, and means for changing the beam diameter of the scanning light flux in accordance with the change of the magnification of the eye image. Characteristic eye image device. 2. A scanning optical system for scanning a light beam on a region of an eye to be imaged, a light receiving unit for receiving the light beam from the region, and an image of the eye to be inspected based on a signal from the light receiving unit. An apparatus including a display means, comprising means for changing a scanning density of scanning on a region to be imaged by the scanning optical system.