JPS63273810A - Endoscope - Google Patents

Abstract

PURPOSE:To make an endoscope compact and to prevent picture quantity from deteriorating even in a light place by arranging an electrooptic element which varies in transmission wavelength range and transmissivity under applied voltage control at the diaphragm position of an object optical system or in a lighting optical system. CONSTITUTION:An electric filter element 17 consists of a color filter 20 composed of an R, a G, and a B filter and an electrochromic element (EC element) 21 which is fixed to the back of the color filter 20k consists of R, G and G sections corresponding to the R, G, and B filters, and enables the individual application of a voltage to the R, G, and B sections. Then the EC element 21 has transmissivity (reflectivity) characteristics corresponding to the applied voltage and characteristics of variation in transmission wavelength band width the level of the applied voltage. Consequently, the whole device and its tip hard part are made compact and deterioration in picture quality is eliminated even in a light place.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an endoscope.

[Prior art and problems to be solved by the invention] When performing field sequential color imaging with a conventional endoscope,
RG as shown in Fig. 10 in the illumination optical system as shown in Fig. 9.
The B rotary filter 1 was arranged to sequentially irradiate different colors of illumination light, but this required a mechanical filter drive device, which caused the problem of increasing the size of the entire endoscope device. . In addition, in the case of the above-mentioned sequential illumination method, if outside light hits the object to be observed in a bright place, white light will be mixed with each color light incident on the solid-state image sensor, degrading the image quality. The problem was that I couldn't use it. In FIG. 9, 2 is a light source, 3 is a condensing lens, 4 is a light guide, 5 is an illumination lens, 6 is an objective lens, 7 is a solid-state image sensor, 8 is an image processing device, 9 is a TV monitor, 10 is the endoscope body.

In addition, in the case of an endoscope that performs treatment using infrared laser light while observing, it is necessary to protect the operator's eyes or to smear the solid-state image sensor (the solid-state image sensor becomes saturated due to excessive input of light and the object An infrared cant filter was placed in the objective optical system to prevent the problem of not being able to obtain an image.
The infrared cut filter is generally an absorption type, that is, it is thick in the optical axis direction, and since it has to be provided in addition to a normal diaphragm, the optical path length of the objective optical system becomes long, and the tip of the endoscope There was a problem that the hard part became long.

SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is an object of the present invention to provide an endoscope in which the entire device and the rigid distal end portion of the endoscope can be configured compactly, and the image quality does not deteriorate even in a bright place.

[Means and effects for solving the problems] The endoscope according to the present invention has a diaphragm position of the objective optical system or an illumination optical system.
By arranging an electro-optical element whose transmission wavelength range and transmittance are modulated by controlling the applied voltage, there is no need for a mechanical filter drive device or an aperture diaphragm, and an RGB filter can be placed in the objective optical system. This is how it was done.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

FIG. 1 is a cross-sectional view of the entire first embodiment, and FIG. 2 is a cross-sectional view of the objective lens thereof, in which 11 is an endoscope main body, 12 is a rigid distal end portion, and 13 is a control portion. 14 is the tip rigid part 12
An objective lens 15 provided within the rigid tip portion 12 is provided at the imaging position of the objective lens 14 and is connected to the signal line 1.
6 is a solid-state image sensor connected to an image processing device (not shown) in the control unit 13; 17 is an objective lens 1;
This is an electric filter element arranged at the aperture position No. 4 and connected to an element control circuit 19 via an element cable 18.

As shown in FIGS. 2 and 3, the electric filter elements 17 have R and G elements arranged in order in the circumferential direction.

A color filter 20 consisting of a B filter, and R, G, and B sections fixed to the back side of the color filter 20 and corresponding to the R2O and B filters, respectively, and voltages are applied to the R, G, and B sections individually. It is composed of an electrochromic element (hereinafter referred to as an EC element) 21. The EC element 21 has a transmittance (reflectance) characteristic according to the applied voltage as shown in FIG. 4, that is, a characteristic in which it becomes almost transparent when the applied voltage is high and becomes almost opaque when the applied voltage is low. Therefore, electric filter element 1
7 is R and G by the element control circuit 19.

By sequentially applying higher voltages to the B section, RlG, B
The sections are made almost transparent one after another, and as a result, the conventional R, G, B
Similar to a rotating filter, the transmission wavelength range is, for example, R, G, B.
and changes in order. Further, by controlling the height of the applied voltage, the transmittance of each section, that is, the amount of light passing through each filter is controlled. Further, the EC element 21 also has a characteristic that the transmission wavelength band width changes depending on the height of the applied voltage, as shown in FIG. It is assumed that the area ratio of the R, G, and B filters is set in advance according to the color sensitivity characteristics of the solid-state image sensor 15.

Referring again to FIG. 1, 22 is a light source, 23 is a light guide, and 24 is an illumination lens. Further, 25 is a part to be observed such as an affected part in the body cavity.

Since the present embodiment is configured as described above, when observing the observed portion 25 illuminated with white light from the illumination lens 24, the element control circuit 19 applies a higher voltage to the RlG and B sections in order. The transmission wavelength range of the electric filter element 17 is indicated by B and G.

By changing R, B, . . . and reading signals from the solid-state image sensor 15 in synchronization with this, color imaging can be performed. At this time, B.

Since reading time from the image sensor is required when changing the transparent portion in order of G and R, in reality, there is a time period in which no light is completely blocked between the transparent states of each color. In the above case, even if external light hits the observed part 25, since the electric filter element 17 is in front of the solid-state image sensor 15, white light will not be mixed with each color light incident on the solid-state image sensor 15, and therefore the image quality will not deteriorate. Does not occur. Further, since the amount of light passing through each filter can be controlled by changing the applied voltage by the element control circuit 19, the electric filter element 17 can also function as an aperture diaphragm. Further, if the applied voltage is lowered, the transmitted wavelength range is limited to the visible light range as shown in FIG. 4, so that the electric filter element 17 can also function as an infrared cut filter. Therefore, there is no need to separately provide an aperture diaphragm, and the electric filter element 17 itself is thinner than a conventional infrared cut filter, so the optical path length of the objective optical system can be shortened, and as a result, the rigid tip portion 12
can be configured compactly. It is also possible to adjust the color balance by controlling the amount of light passing through each filter. Furthermore, since this embodiment eliminates the need for a mechanical filter drive device, the entire device can be configured compactly.

Further, the EC element 21 transmits light between 0.4 and 1.5μ.

Since an opaque state can be created, an IR (near infrared) filter can be placed in place of the R, G, and B filters, or four or more colors can be added.
Alternatively, if you select G, R, or IR, you can easily create pseudocolors.

Note that the electric filter element 17 of this embodiment may be placed in the illumination optical system, and in that case there is an advantage that the entire apparatus can be configured compactly. As for the specific arrangement position, for example, as shown in FIG. 5(A), the light a22
and the condenser lens 26, or between the output end of the light guide 23 and the single fiber 27 that transmits light to the illumination lens 24 as shown in FIG. 5(B). Further, in that case, the area ratio of the R, G, and B filters is set according to the color distribution characteristics of the light source 22.

FIG. 6 shows an electric diaphragm element 28 used in the second embodiment, which includes a plurality of ring-shaped sections 28a, 28.
b, 28c, 28d, and 28e, and is composed of an EC element that can apply a voltage individually to the sections, and is placed at the aperture position of the objective optical system in the same manner as the electric filter element 17 described above (see Fig. 1). reference).

Since the present embodiment is constructed as described above, if a voltage is not applied to the central sections 28a, 28b, 28c and no voltage is applied to the outer peripheral sections 28d, 28e, as shown in FIG. As shown in A), the transparent part and the non-transparent part B
is formed. Then, by selecting and changing the voltage application section, the area to the transmission part is changed, and the aperture function is exerted. Furthermore, if the applied voltage is lowered in synchronization with the use of an infrared laser, the transmission wavelength range is limited to the visible light range due to the characteristics shown in FIG. 4, so that the function as an infrared cut filter is exhibited. This situation is shown in the timing chart of FIG.

Thus, in this embodiment, since the electric diaphragm element 28 also has a function as an infrared cut filter, there is no need for an infrared cut filter, and as a result, there is an advantage that the objective optical system can be configured compactly.

Incidentally, both the electric filter element 17 of the first embodiment and the electric aperture element 28 of the second embodiment may be arranged at the aperture position of the imaging optical system of a television camera externally attached to the fiberscope. Furthermore, each section of the electric filter element 17 can be subdivided into electric diaphragm elements 28, and each section can be made to function as an electric diaphragm element. In that case, if only the function of opening and closing each compartment is desired, a liquid crystal shutter can be used instead of the EC element. It is also possible to provide the above-mentioned elements in both the objective optical system and the illumination optical system.

〔Effect of the invention〕

As described above, the endoscope according to the present invention has the practically important advantage that the entire device and the rigid distal end portion can be configured compactly, and there is no deterioration in image quality even in a bright place.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a first embodiment of an endoscope according to the present invention, FIG. 2 is a sectional view of an objective lens of the first embodiment, and FIG. 3 is a sectional view of an objective lens of the first embodiment.
A front view of the electric filter element of the example, FIG. 4 is a diagram showing the transmittance (reflectance) characteristics according to the applied voltage of the EC element,
FIG. 5 is a sectional view showing an example in which the electric filter element is arranged in an illumination optical system, FIG. 6 is a front view of the electric diaphragm element of the second embodiment, and FIGS. 7 and 8 are the electric diaphragm elements of the second embodiment. Front view and timing chart showing the operating state of the element, No. 9
The figure is a sectional view of a conventional example, and FIG. 10 is a front view of a conventional rotary filter. 11... Endoscope main body, 12... Tip rigid part, 1
3...control unit, 14...objective lens, 15...
...Solid-state image sensor, 16...Signal line, 17...
Electric filter element, 18...element cable, 1
9... Element control circuit, 20... Color filter, 21... Electrochromic element, 22...
. . . Light source, 24 . . . Illumination lens, 25 . . . Observed section, 26 . . . Condenser lens, 27 . Figure 5 Figure 16 Off view

Claims (1)

[Claims] An endoscope in which an electro-optical element whose transmission wavelength range and transmittance are modulated by controlling applied voltage is arranged in the aperture position of an objective optical system and/or in an illumination optical system.