Omnidirectional endoscope apparatus

#The present invention relates to an omnidirectional endoscope apparatus having a viewfield covering all around the periphery in the peripheral direction.

#An endoscope is effective as an apparatus for observing the inner periphery of a narrow and/or elongated space such as the inside of a cylinder block of an engine and the inside of piping, for example. On the other hand, since a typical endoscope has a limited view field angle, such operation as to turn the endoscope is required for the user in order to observe all around the periphery. In this respect, an omnidirectional endoscope which can receive an incident light from all around the periphery in the peripheral direction and take it into image transmitting means is effective because the user can see all around the periphery at a time. As one example of such an omnidirectional endoscope, an endoscope is known which is equipped with, for example, a conical prism placed at a distal end of its insertion section. A distal end face of a light guide (illumination light transmitting means) occupies a position slightly on the basal end side of the conical prism. An illumination light is radially emitted obliquely forward from this distal end face and illuminates an object to be observed. (See the Japanese Patent Application Unexamined (Laid-Open) Publication No. H10-318727.)

#In the above known omnidirectional endoscope, the light guide is fixedly embedded in the insertion section. Accordingly, the positional relation between the distal end face of the light guide and the conical prism is held constant. For this reason, it has such a problem that an image looks dark because when the inside diameter of a space of the object to be observed is small, the illumination light strikes upon the inner peripheral surface of the space more on the basal end side than the view field region, and when the inside diameter of the space is large, the illumination light strikes upon the inner peripheral surface of the space more on the distal end side than the view field region.

#FIG. 1 is a side view of an omnidirectional endoscope apparatus according to one embodiment of the present invention.

#FIG. 2 is a side view showing the above omnidirectional endoscope apparatus in its exploded manner.

#FIG. 3 is a sectional view of a tip part of the omnidirectional endoscope apparatus.

#One embodiment of the present invention will be described hereinafter with reference to the accompanying drawings.

#FIGS. 1 and 2 show an omnidirectional endoscope apparatus 1. The omnidirectional endoscope apparatus 1 comprises an endoscope 10, an omnidirectional light receiving unit 20 (omnidirectional light receiving mechanism), and an illumination light transmitting unit 30 (illumination light transmitting mechanism). Those component elements 10, 20, 30 are removably united together.

#The endoscope 10 includes a main body section 11 having an eyepiece part 11a, and a metal-made insertion section 12 extending linearly along an axis LO from a tip shaft 11b of the main body section 11. The material of the insertion section 12 is not limited to hard metal but it may be flexible material such as resin.