JPH0679110B2 - Endoscope device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope apparatus, and more particularly to an endoscope apparatus that images a subject.

[Prior Art] As a conventional art, as shown in, for example, Japanese Utility Model Publication No. 59-31212, a solid-state image sensor is inserted at the tip of the endoscope instead of providing an image guide in the endoscope, and There is an endoscopic device that picks up an image and supplies an image signal via an endoscope to an external monitor for display. The performance of such an endoscope apparatus depends on the performance of the solid-state image sensor. In particular, it is desired that the number of pixels is large. However, since an endoscope is often inserted into a narrow tubular member or a body cavity, there is also a circumstance that the diameter of the tip cannot be increased.

[Problems to be Solved by the Invention] As described above, in the related art, the contradictory requirements of a large number of pixels and a small shape have been imposed on the solid-state imaging device built in the tip of the endoscope. The present invention has been made in view of such a problem, and an object thereof is to provide an endoscope apparatus that images a subject with high resolution without increasing the diameter of the endoscope.

[Means for Solving Problems] According to the endoscope apparatus of the present invention, means for irradiating a subject with two-dimensional scanning of spot light and means for photoelectrically converting reflected light from the subject are provided. There is.

[Operation] In this device, the object is illuminated while the spot light is two-dimensionally scanned, the reflected light from the object is photoelectrically converted by the light receiving element, and the photoelectric conversion output is written in the storage means in correspondence with the scanning of the spot light. , The two-dimensional distribution of the reflection intensity on the subject, which is the same as when the subject is imaged using the image sensor,
That is, an optical image is required.

Embodiment An embodiment of the endoscope apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the first embodiment. A light source unit 19 and a video processor 22 are connected to the endoscope body 10. The light source unit 20 has an electron gun 44 and a fluorescent plate 52, and an electron beam 46 from the electron gun 44 is an electron lens.
After being converged at 48, the fluorescent coil 52 is two-dimensionally raster-scanned by the deflection coil 50. By irradiating the electron beam 46, the spot light generated from the fluorescent plate 52 is focused on the imaging lens 54.
Then, the light is focused on the surface 56, and then enters the Sefoc fiber lens 18 through the rotary color filter 60. The imaging lens 54 has a role of a relay lens for increasing the amount of light incident on the SELFOC fiber lens 18 and a role of correcting chromatic aberration of the SELFOC fiber lens 18. The rotary color filter 60 has R (red) and G as shown in FIG.
The transmission color filters of three primary colors (green) and B (blue) are sequentially arranged along the circumference of the disk. The filters for the respective colors are switched by the motor 58 during the rest time when one raster scan of the electron beam is completed.

The spot light incident on the SELFOC fiber lens 18 is magnified by the magnifying lens 16 at the tip of the endoscope in accordance with the required light distribution angle and projected onto the object 20 to illuminate the object. Therefore, the spot light scans the subject 20 in accordance with the raster scanning of the electron beam. Further, the spot light is switched to the three primary colors of R, G, and B for each scanning. Light reflected from the subject 20 is photoelectrically converted by the light receiving element 12 built in the tip of the endoscope 12. Since the part photographed by the endoscope is a part such as the inside of the body cavity where there is no or almost no natural light, only the reflected light of the part irradiated with the spot light is incident on the light receiving element 12. Here, since the spot light is raster-scanned, the light receiving element 12 outputs the two-dimensional distribution information of the reflection intensity on the subject 20 in time series. As a result, even if the light-receiving element 12 does not function as an image sensor,
Even if there are only pixels, the subject is substantially imaged and scanned.

The light receiving signal output from the light receiving element 12 is supplied to the video processor 22 via the preamplifier 14. The received light signal is first subjected to signal processing necessary for the TV signal in the AGC (auto gain control) circuit 24 and the γ correction circuit 26 in the video processor 22, and then digitized by the A / D converter 28. The digitized TV signal is synchronized with one raster scan of the electron beam by the multiplexer circuit 30, that is,
Switching is performed in synchronization with the timing when each primary color of the rotary color filter 60 is switched. Then, the TV signal when illuminated by the R spot light is the frame memory 32-1 for the RT image.
In addition, the TV signal when illuminated by the G spot light is supplied to the frame memory 32-2 for the G image, and the TV signal when illuminated by the B spot light is supplied to the frame memory 32-3 for the B image. It When the three component images of R, G, B are written in the frame memories 32-1, 32-2, 32-3, the signals in the frame memories 32-1, 32-2, 32-3 are arranged in parallel. To the D / A converters 34-1, 34-2, 34-
3 to the color monitor 36.

Switching of the multiplexer 30, frame memory 32-1,
The timing generator 42 provided in the light source unit 19 controls the reading and writing of 32-2 and 32-3 and the control of the color monitor 36.
Controlled by. Timing generator 42 is an electron gun
It also controls the raster scan of the electron beam from 44 and the motor 58 for rotating the rotary color filter 60. The rotation of the rotary color filter 60 is detected by an optical rotation detector 62 provided corresponding to the outer peripheral portion of the disk, and the output of the rotation detector 62 is supplied to the timing generator 42.

On the other hand, the received light signal input into the video processor 22 is also supplied to the comparator 40 via the low pass filter 38. The comparator 40 compares this received light signal with a reference voltage and negatively feeds back the difference to the acceleration voltage of the electron gun 44. This makes the electron gun 44
The accelerating voltage is automatically adjusted, and the intensity of illumination light is automatically adjusted.

As described above, according to the first embodiment, since the endoscopic imaging is performed under the dedicated light source, the spot light from the dedicated light source is two-dimensionally scanned on the subject instead of scanning the subject on the image sensor. The reflected light signals output from the light receiving element in time series are written in the memory in correspondence with the scanning of the spot light, so that the reflection intensity information of the object can be 2
A dimensional distribution, that is, an optical image is obtained. Therefore, a lens system for forming a subject image on the light receiving surface is unnecessary.
In this case, the resolution of the captured image reduces the spot light diameter. Alternatively, since it is improved by increasing the number of scanning lines, it is possible to realize an endoscope apparatus that can image a subject with high resolution without increasing the diameter of the endoscope tip.

In the first example, the Selfoc fiber lens is used.
By moving the entrance end of 18 in the direction of the arrow shown in the figure, the raster scanning range of the spot light on the subject 20 can be varied, and the image to be captured can be enlarged or reduced freely.

A second embodiment of the present invention is shown in FIG. The second embodiment does not switch the illumination of the three primary colors with the rotating color filter, but
It is equipped with three light sources, and light from each light source is sequentially irradiated to switch the illumination of the three primary colors. R, G, and B laser oscillators 70, 72, and 74 are provided, and these laser oscillators 7
Dichroic mirrors 76, 78, which reflect only the laser beams of R, G, B respectively from the laser beams 0, 72, 74,
It is incident on a rotating polyhedral mirror (polygon mirror) 82 for deflection in the X direction via 80, and is deflected in the X direction (vertical direction on the paper surface of the drawing). The X-polarized laser beam reflected by the rotating polyhedron mirror 82 is incident on the rotating polyhedron mirror 84 for deflection in the Y direction and is deflected in the Y direction (direction perpendicular to the plane of the drawing). XY emitted from this rotating polyhedral mirror 84
The polarized laser beam is imaged by the imaging lens system 86 at the position of the surface 88, and then is incident on the SELFOC fiber lens 18. The other structure is similar to that of the first embodiment, and the description thereof is omitted.

With such a configuration, the laser oscillators 70, 72, and 74 are switched at the same timing as the timing at which the rotary color filter 60 is switched in the first embodiment, and operate similarly to the first embodiment. Since the laser beam has a smaller diameter than the electron beam from the electron gun, the resolution of the second embodiment can be further improved as compared with the first embodiment.

The rotating polygon mirrors 82 and 84 may be replaced with optical angle modulators that apply surface waves.

FIG. 4 shows a third embodiment of the present invention. In this embodiment, a light source unit is not provided, and a laser oscillator 92 and an optical angle modulator 94 that applies a surface wave are built in the tip of the endoscope main body 10, and a laser beam is scanned at the tip of the endoscope.

The present invention is not limited to the above-described embodiment, but can be variously modified. Although the color filters for the three primary colors are switched for each frame in the first and second embodiments, the rotary color filter may be rotated at high speed to switch the R, G, and B illumination for each predetermined pixel. Then, if signal processing similar to that of a single-tube camera using a conventional stripe filter or a solid-state imaging device camera having a color mosaic filter attached on the front surface is performed, the frame memories 32-1 and 32- 2, 32-3
Becomes unnecessary.

As described above, according to the present invention, since the image pickup device does not scan the subject but the illumination light scans the subject, it is not necessary to provide the image pickup device as a light receiving unit, and a single pixel is provided. It is only necessary to provide the light receiving element of. Therefore, the resolution of the captured image is determined by the diameter of the spot light and the number of scanning lines that two-dimensionally scans the subject, and therefore the endoscope apparatus that can capture the subject with high resolution without increasing the diameter of the endoscope. Will be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a first embodiment of an endoscope apparatus according to the present invention, FIG. 2 is a view showing a rotary color filter used in the first embodiment, and FIG. 3 is an endoscope according to the present invention. FIG. 4 is a view showing a main part of a second embodiment of the endoscope apparatus, and FIG. 4 is a view showing a main part of a third embodiment of the endoscope apparatus according to the present invention. 12 ... Photodetector 30 ... Multiplexer 32-1, 32-2, 32-3 ... Frame memory 36 ... Color monitor 42 ... Timing generator 44 ... Electron gun 50 ... Deflection coil 52 ... Fluorescent plate 60 ... … Rotation color filter

Claims (1)

[Claims] 1. Spot light irradiation means for irradiating a subject with spot light scanned at a predetermined cycle from the tip of an endoscope; and photoelectric conversion by receiving reflected light from the subject with a single light receiving surface. A photoelectric conversion means, a frame memory that stores output signals obtained in time series from the photoelectric conversion means in association with scanning of the spot light based on the predetermined cycle, and a signal stored in the frame memory And a means for displaying the image of the subject based on the above.