JPS5977830A - Luminous light amount variable type eye bottom camera - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] The present invention automatically corrects the loss of illumination light for fundus observation that occurs when the angle of the optical axis of the objective lens is changed in order to observe and photograph the peripheral part of the fundus. This invention relates to a fundus camera with a variable illumination aperture that allows a good fundus image to be observed at all times.

Conventionally, in order to observe and photograph the peripheral part of the fundus, it has been known that the angle of the optical axis of the objective lens is changed by swinging the fundus camera 'Ir: in the horizontal and vertical planes around the pupil of the subject's eye. ing. As shown in Fig. 1, when the optical axis of the objective lens is at the normal position @Avc, the incident state of the fundus illumination light to the eye 1 to be examined (the state in which the ring slit image is projected to the anterior segment) is as follows. In this case, the illumination light (ring slit image) 2 is applied to the crimson color 3 as shown in Fig. 2 (a).
However, when the optical axis of the objective lens is at the false elevation positions B and C due to the 1^ elevation of the fundus camera, the incident situation of the fundus illumination light to the eye 1 becomes In this case, the illumination portion is blocked by the iris 3, resulting in a problem that the fundus image obtained by the observer becomes extremely dark. A similar problem also occurs when the fundus camera is rotated horizontally around the pupil of the eye 1 to be examined. Therefore, 1. Adjusting the amount of illumination light in these cases has been considered, but since the degree of vignetting of illumination light 2 by iris 3 changes as the angle of the optical axis of the objective lens changes, It was very important for the examiner to make adjustments.

In view of the above-mentioned problems with VCM, the present invention includes an illumination light amount control circuit that can automatically change the light amount of observation illumination light in response to changes in the horizontal rotation angle and /' or vertical swing angle of the fundus camera. The purpose of this invention is to provide a fundus camera with a variable illumination amount that allows a good fundus image to be observed at all times.This will be explained below based on an embodiment shown in FIGS. If shifted, in FIGS. 31Δ to 5,
11 is a base having a pivot 11a; 12 is a horizontal rotation shaft supported horizontally rotatably by the pivot 11aK via a bearing 13; and 14 is a bracket fixed to the upper end of the horizontal rotation shaft 12. 15 is a gear fixed to the lower end of the horizontal rotation I-shaft 12; 16 is an output shaft fixed to the inner wall of the pivot portion 11a and has a gear 17 that meshes with the gear 15;
18 is a transmission gear fixed to one end of the output shaft 16, 19 is a variable resistor to which a transmission gear 20 that meshes with the transmission gear 18 is fixed to the manual shaft 19a, and 21 is an output terminal, which detects the rotation angle. configuring the device. In addition, in the rotation angle detection device, as shown in FIG. 6, a rotary encoder 22 or a potentiometer (
(not shown) f! r: May be used. Also, instead of directly fixing the transmission gear 18f and the output shaft 161/l, an appropriate rotation transmission means may be interposed between the output shaft 16 and the transmission gear 18. In FIGS. 3 and 7, reference numeral 23 denotes an inner peripheral edge 23a that is fixed to the bracket 14 and coincides with the circumference of a vertical circle centered on the pupil position of the eye to be examined at the time of examination.
and an arc-shaped arm having an outer peripheral edge 23b and an arc-shaped long hole 23c formed in the longitudinal direction; 24 is the long hole 23c;
An arcuate rack 25 is fixed to the arcuate arm 23 along the inner peripheral edge 23a and outer peripheral edge 2 of the arcuate arm 23.
3bK A sliding body 26 having a plurality of rollers 25a in contact with each other and slidably mounted on the arcuate arm 23;
27 is a fundus camera body fixed to the sliding body 25; 27 is a pinion fixed to the output shaft 28 pivotally mounted to the sliding body 25 and meshed with the arcuate rack 24;
8 is connected to another rotation angle detection device similar to the rotation angle detection device shown in FIG. 5 or 6, either directly or via a suitable rotation transmission means. FIG. 8 shows an illumination light amount control circuit, where 29 is a horizontal rotation angle detection circuit connected to the output terminal 21 of the rotation angle detection device for horizontal rotation angle detection, and 30 is a rotation angle detection circuit for vertical swing angle detection. A vertical swing angle detection circuit connected to the output terminal 21 of the detection device; 31 and 32 are signal conversion circuits that convert the output signals of the horizontal rotation angle detection circuit 29 and the vertical swing angle detection circuit 30 into appropriate signals, respectively; 33 controls the observation illumination light dimming circuit 35 according to the illumination conditions set in advance or by the illumination condition setting circuit 34 when the signal from the signal conversion circuit 31 and/' or 32 is input manually, and adjusts the light intensity of the observation illumination light. A control circuit 36 controls the dimming circuit 35 so that the amount of illumination light increases as the horizontal rotation angle and/or vertical swing angle of the fundus camera increases. Alternatively, it is a storage circuit that stores an arbitrary horizontal rotation angle and/or vertical swing angle and the illumination light M corresponding to the angle. It is assumed that the ratio of the change in the amount of illumination light to the change in the horizontal rotation angle and /' or the vertical swing angle fiK can be arbitrarily set by the examiner using the illumination condition setting circuit 34. In addition, the observation illumination light dimming circuit 35 has a changeover switch to a mode in which the examiner can set the illumination light amount VC as desired regardless of the horizontal rotation angle and/or the swing angle. shall be taken as a thing. The control circuit 33 also has a function of reading information from the storage circuit 36 as necessary and controlling the dimming circuit 35 so that the amount of illumination light is adjusted to the corresponding angle. Therefore, the rate of increase in the amount of illumination light set by the illumination condition setting circuit 34 can be stored in the storage circuit 36 by the control circuit 33, and can be recalled and used at any time.

Since the variable illumination light amount fundus camera according to the present invention is configured as described above, for example, when the bracket 14 is horizontally rotated due to the horizontal rotation of the fundus camera body 26, the horizontal rotation axis 1
2 rotates, and this rotation causes gears 15 and 17. Output shaft 16
9 is transmitted to the variable resistor 19 via the speed change gears 18 and 20 of the rotation angle detection device. Further, when the sliding body 25 slides against the arcuate animum 23 due to the vertical swinging of the fundus camera body 26, the pinion 27 rotates, and this rotation causes the output shaft 28,
The signal is transmitted to the iJ variable resistor 19 via the transmission gears 18 and 20 of other rotation angle detection devices. The outputs of these two variable resistors 19.19 are transmitted to the horizontal rotation angle detection circuit 29 and the vertical rotation angle detection circuit 30 via output terminals 21.21, respectively, and the outputs of the rain detection circuits 29 and 30 are transmitted to the horizontal rotation angle detection circuit 29 and the vertical rotation angle detection circuit 30. The signal conversion circuit 31 controls the observation illumination light dimmer circuit 35'fr: to adjust the light Mt of the observation illumination light according to predetermined illumination conditions. In addition, the examiner can use the illumination condition setting circuit 34.
If the illumination conditions are arbitrarily set, the control circuit 33 controls the dimming circuit 35 in accordance with the illumination conditions to adjust the amount of illumination light for viewing and observation. Further, the control circuit 33 can store specific or arbitrary illumination conditions in the storage circuit 36 as necessary, and thereby can read the memory at any time to adjust the amount of illumination light. In this way, the amount of illumination light for observation is automatically adjusted in response to changes in the horizontal rotation angle and/or vertical swing angle of the fundus camera, regardless of the angle of the optical axis of the objective lens of the fundus camera. The examiner can always obtain a sufficiently bright and good image of the fundus, and is freed from the complicated work of adjusting the amount of illumination, which is required every time the fundus camera is rotated horizontally and/or vertically.

As described above, the variable illumination amount fundus camera according to the present invention has important practical advantages in that it is possible to always observe a good fundus image and it can relieve the examiner from the complicated task of adjusting the illumination scene. .

[Brief explanation of drawings]

Figure 1 shows the movement of a conventional fundus camera [t11 side view] Figure 2 is a diagram showing the incidence of fundus illumination light on the subject's eye according to the conventional example, Figure 3 is the amount of illumination light according to the present invention A side view of one embodiment of the variable fundus camera, FIG. 4 is a vertical cross-sectional view of the horizontal rotation mechanism of the above embodiment, and FIGS. 5 and 6 are respectively the rotation angle plug tiO! of the above embodiment. FIG. 7 is a vertical sectional view of the vertical swing mechanism of the above embodiment, and FIG. 8 is a block diagram of the illumination light amount control circuit of the above embodiment. 11...Base, 12...Horizontal rotation axis, 13...
...Bearing, 14...Bracket, 15.17...
... Gear, 16 ... Output shaft, 18.20 ... Speed change gear, 19 ... Variable resistor, 21 ... Output terminal, 23 ... Arc-shaped arm, 24 ... ... arcuate rack, 25 ... sliding body, 26 ... fundus camera body,
27...Pinion, 28...Output end, 29...
...Horizontal rotation angle detection circuit, 30...Vertical swing angle detection circuit, 31.32...Signal conversion circuit, 33...
Control circuit, 34... Lighting condition setting circuit, 35...
- Observation illumination dimmer circuit, 36... memory circuit. Agent Yasushi Shinohara Figure 4 Figure 5

Claims (3)

[Claims] (1) In a fundus camera that can horizontally rotate or vertically swing around the pupil of the subject's eye, the amount of observation illumination light changes when the fundus changes in the horizontal rotation angle and/or vertical swing angle of the mela. 1. A retinal camera with variable illumination/brightness, characterized by having an illumination light amount control circuit that can automatically change the amount of illumination. (2) Claims characterized in that the examiner can arbitrarily set the ratio of change in the illumination scene for observation to the amount of change in the horizontal rotation angle and/or the vertical swing angle.
) variable illumination light amount fundus camera. (3) The horizontal rotation angle and /' or vertical swing angle and the amount of observation light corresponding to the angle are memorized, and this information can be recalled at any time to adjust the illumination light ffi corresponding to the relevant angle. Patent featuring all features