JPH0311446B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in light transmission between a light exit end of an image guide of an endoscopic device and an imaging device.

FIG. 1 is a schematic diagram of a conventional endoscope device equipped with a video device.
2 is a photodetector section 2 in which a plurality of photodetectors are arranged in a matrix and converts an optical signal into an electrical signal.
3 is an amplifier for amplifying the electrical signal from the image sensor, 4 is a process circuit, 5 is an encoder, 6 is a display circuit, 7 is a display device, and 8 is a synchronization device. circuit, 9 is optical lens system, 10
is a moire prevention filter, in which the image of the affected area is transmitted from the image guide 1, passes through the optical lens system 9 and the moire prevention filter 10, is received by the image sensor 2, is photoelectrically converted, and is transmitted to the amplifier 3, the process circuit 4, and the encoder. 5 and converted into a video signal. The information is then recorded on a magnetic tape or displayed on a display device 7 such as a cathode ray tube via a display circuit 6. By the way, in this type of endoscope device,
An optical lens system 9 and a moiré prevention filter 10 must be disposed between the image guide 1 and the image sensor 2, which increases the cost of the device.Furthermore, since the lens system is used, the operation section of the device is difficult to operate. It is heavy and has problems with operability. As a method of eliminating such defects, a method can be considered in which the light emitting end of the image guide 1 and the light receiving surface of the image sensor 2 are brought into close contact with each other, as shown in FIG. However, in this method, the optical fibers constituting the image guide and the photodetector that receives light do not correspond to each other, resulting in strong moiré fringes. When moire fringes occur, it becomes difficult to accurately observe the image of the affected area, which may impede appropriate treatment. Particularly in systems that combine an image guide and a scanning system, moiré fringes are likely to occur, and reducing moiré fringes is an important issue.

In view of such circumstances, the present invention provides an endoscope device in which an image transmitted from a single optical fiber constituting an image guide is received by a plurality of photodetectors, eliminating the need for an optical lens system and having fewer moire fringes. It's about doing.

Hereinafter, based on the illustrated embodiment, the same or similar members as shown in FIGS. 1 and 2 will be described with the same reference numerals. Moiré fringes do not occur when the optical fibers constituting the image guide 1 and the photodetecting section 2a correspond to each other, but they occur when they do not correspond to each other. However, it is impossible to strictly match the arrangement pitch of the optical fibers and the sampling pitch of the photodetector 2a. Therefore, as a method to reduce the moiré fringes that occur between the optical fiber and the photodetector, the optical fiber can be made thicker or each photodetector can be made smaller to reduce the area of one pixel detected by the photodetector. On the other hand, the image area ratio transmitted from one optical fiber is increased so that the light is received by a plurality of photodetectors. However, the resolving power of an endoscope is substantially determined by the diameter of the optical fiber, and it is not preferable to make the diameter of the optical fiber large over the entire length including the light receiving portion because it reduces the resolving power of the endoscope. It is also impossible to reduce the size of the photodetector due to cost and manufacturing issues. Therefore, by making the light-receiving part of the image guide small in diameter and the light-emitting end in a large diameter, it is possible to transmit light from a single optical fiber without reducing the resolution of the endoscope, and to obtain a photodetector with a pixel area. It is possible to increase the image area ratio that is transmitted to the image, and it is possible to reduce the occurrence of moiré fringes. FIG. 3 shows the configuration of an embodiment according to the present invention, in which the light receiving part 1a and the intermediate light transmitting part of the optical fiber constituting the image guide 1 have a small diameter, and the diameter gradually increases from the vicinity of the light emitting end. An image transmitted from a single diameter optical fiber can be received by a plurality of photodetectors 2a.
The image of the affected area is received by the light-receiving part 1a with a small diameter, passes through an intermediate light transmission part, passes through a light-emitting end whose diameter is gradually larger than that near the light-emitting end, and is received by a plurality of photodetectors 2a. be done. As a result, an image transmitted through one optical fiber can be received by a plurality of photodetectors 2a. In Fig. 3, the optical fiber constituting the image guide has a small diameter at the light receiving part 1a and the middle part, and a thick diameter only at the light emitting end. It goes without saying that the same effect can be obtained even if the diameter of the injection end is made larger. Also, considering the resolving power in light transmission between the image guide and the image sensor, if the sampling pitch of the photodetector is larger than the arrangement pitch of the optical fibers that make up the image guide, the resolving power of the endoscope will be lower than that of the photodetector. The sampling pitch is almost the same as that of , and even if the resolving power of the image guide is increased by using thin optical fibers, the effect cannot be achieved. On the other hand, if the sampling pitch of the photodetector is made smaller than the array of optical fibers, the resolving power of the image guide can be maintained almost as is, and the resolving power of the endoscope can also be greatly improved.

As explained above, according to the present invention, it is possible to reduce the occurrence of moiré fringes by a simple method, and it is also possible to prevent a decrease in the resolution between the image guide and the image sensor, thereby improving the quality of the endoscope. This makes it possible to further improve image quality.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional endoscope device equipped with a video device, and FIG. 2 is a schematic diagram of an endoscope device in which the light emitting end surface of an image guide and the light receiving surface of an image sensor are brought into close contact with each other.
FIG. 3 shows a configuration diagram of an endoscope apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1... Image guide, 1a... Light receiving part of image guide, 2... Image pickup element, 2a... Light detection part, 2b... Scanning circuit, 3... Amplifier, 4... Process circuit, 5... Encoder, 6...Display circuit, 7
... Display device, 8 ... Synchronization circuit, 9 ... Optical lens system, 10 ... Moiré prevention filter.

Claims (1)

[Claims] 1. An endoscope device equipped with an image sensor that receives optical images transmitted from an image guide by a plurality of photodetectors arranged in a matrix and converts the optical signals into electrical signals. In this method, an optical image transmitted by a single optical fiber is received by multiple photodetectors using an image guide made of an optical fiber whose light-emitting end has a larger diameter than the light-receiving part. An endoscope device designed to obtain 2. The endoscope device according to claim 1, wherein the light emitting end surface of the image guide and the light receiving surface of the image sensor are in close contact with each other. 3. The endoscope according to claim 1, wherein the image guide is composed of a bundle of optical fibers whose light emitting end is formed thicker in a substantially conical shape than the light receiving part and the light transmitting part in the middle. Device.