JP3917702B2 - Endoscope device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an endoscope apparatus that obtains a subject image by projecting a frequency-modulated light spot onto a subject.
[0002]
[Prior art]
A conventional electronic endoscope is provided with an ultra-small image sensor at its tip, and a light guide built in the endoscope insertion part is used to guide illumination light from the outside of the body to the tip. Then, the output of the image sensor was processed electrically and displayed on the television monitor.
[0003]
[Problems to be solved by the invention]
However, the drive signal and output signal of the image sensor are high-frequency, and there is a problem that electromagnetic waves are easily radiated outside the endoscope. Moreover, the electric wire which transmits an electric signal had to be made thin, and there was a case where the electric wire was disconnected and the image disappeared.
[0004]
Furthermore, there is a problem that it is difficult to connect an image sensor having many terminals and many electric wires.
In addition, there is a problem that a signal cable from the imaging device becomes long, and noise is likely to occur on the electric wire inside the endoscope due to electromagnetic waves flying from the outside, making it difficult to view an image due to the noise.
[0005]
(Object of invention)
The present invention has been made in view of the above points, and provides an endoscope apparatus that can prevent noise from being emitted from an endoscope and that can be observed without being affected by external noise. The first purpose.
[0006]
Furthermore, it is possible to provide an endoscope apparatus having many advantages such as prevention of disconnection of electric wires, elimination of complicated wiring work, and high resolution without increasing the diameter of the insertion portion. Second purpose.
[0007]
[Means for Solving the Problems]
In an endoscope apparatus that projects light onto a subject from the front end side of an elongated insertion portion, and enables observation of a subject image on the rear end side of the insertion portion via an objective optical system,
Projecting means for projecting a plurality of light spots whose emission intensities are modulated at a plurality of frequencies onto a subject;
A light receiving means for receiving reflected light of a plurality of light spots projected on the subject;
Frequency separating means for frequency separating the output of the light receiving means;
Detection means for detecting the brightness of the reflected light from the output signal separated by the frequency separation means;
By providing a light receiving means that does not need to be driven by a high-frequency drive signal, it is possible to substantially eliminate noise radiated to the outside even when a signal line is inserted into the endoscope, and externally. Thus, it is possible to easily shield the noise and obtain an endoscopic image with good image quality.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows the basic configuration of the endoscope apparatus of the present invention.
[0009]
As shown in FIG. 1, an endoscope apparatus 1 according to the present invention includes an illumination unit 3 that illuminates a subject 2, an imaging unit 4 that images the illuminated subject 2, and an image display unit 5 that displays the captured subject image. It consists of.
[0010]
The illumination unit 3 includes a light source 6 that generates illumination light, spatial coding means 7 that spatially codes the illumination light of the light source 6, and a projection lens 8 that projects the spatially-coded light onto the subject 2.
[0011]
In addition, the imaging unit 4 includes an imaging lens 9 that connects an image of the subject 2 illuminated with spatially-coded light, a photoelectric conversion unit 10 that performs photoelectric conversion on the image, and decoding ( (Decoding) spatial decoding means 11 and video signal synthesizing means 12 for performing processing for generating a video signal on the signal decoded by the spatial decoding means 11, and output from the video signal synthesizing means 12 The video signal is input to the image display means 5 to reproduce and display the subject image on the display screen.
[0012]
For example, as shown in FIG. 2, the illumination unit 3 in FIG. 1, the light of the lamp 6 </ b> A as a light source becomes light that is spatially coded by a spatial coding member 7 </ b> A disposed in front of the optical path. The The spatial coding member 7A is driven by a spatial coding member drive circuit 7B to perform spatial coding.
[0013]
In this spatial coding member 7A, for example, the incident surface on the lamp 6A side and the exit surface on the projection lens 8 side are divided into a number of regions 13, and light incident on the incident surface of each region 13 is incident on the other regions 13. The light is coded or coded differently from the light, and is emitted from the exit surface and projected onto the subject side via the projection lens 8. The spatial coding means 7 is formed by the spatial coding member 7A and the spatial coding member drive circuit 7B.
[0014]
In FIG. 2, illumination light over a two-dimensional area is directly spatially coded, but as described below, a line-shaped area coding means for coding a line-shaped area and a direction perpendicular to the line. Alternatively, the two-dimensional area may be coded by the driving means that scans the image.
[0015]
FIGS. 3A and 3B show a mechanically driven spatial coding unit, more specifically, a frequency modulation coding unit 20 that modulates using a frequency. Here, the frequency modulation does not mean the frequency modulation of the electric signal, and is used in a simplified expression that the signals are modulated at different frequencies.
[0016]
The first fiber array 22 composed of the first fibers 21a, 21b,..., 21n is arranged in parallel at a constant pitch interval, for example, on the horizontal plane of the illumination light path of the light source 6. In this case, the incident ends on the light source 6 side are arranged to be aligned, but the emission ends are arranged so as to be sequentially different (for example, by an integral multiple of a certain length).
[0017]
Opposite to the exit end of the first fiber array 22, the end face on the incident side of the second fiber array 25 comprising the same number of second fibers 24a, 24b,..., 24n as the first fibers 21 is arranged. The fiber pressing member 26 is fixed. In the middle of each of the second fibers 24i (i = a, b,..., N), play is provided, and the exit ends are also arranged in a horizontal plane with a constant pitch and are opposed to these end faces. The projection lens 8 is disposed, and the light transmitted by the second fiber array 25 is transmitted to the subject side (when the endoscope 15 shown in FIG. 4 described later is used, the illumination light transmission image guide 33a of the endoscope 15). To project.
[0018]
The second fiber array 25 is also arranged so that the end face position on the incident side of each second fiber 24i is gradually shifted in the longitudinal direction, and is opposed at a position slightly spaced from the exit end of each first fiber 21i. The fiber holding member 26 is fixed so as not to move near the incident end.
[0019]
Further, a light shielding plate 27 having a function of shielding light is disposed between the emission end of each first fiber 21i and the incident end of the second fiber 24i opposite thereto, and the lower end of each light shielding plate 27 is Each is fixed to one end of the diaphragm 28, and the other end of each diaphragm 28 is attached to a piezoelectric element (or piezoelectric actuator) 29.
[0020]
Each diaphragm 28 is disposed along the length direction below the first fiber 21i, and the other end is attached to the piezoelectric element 29 such that each diaphragm 28 has a different length. The resonance frequencies are set differently.
[0021]
Each piezoelectric element 29 is connected to a piezoelectric element driving circuit 30 via a lead wire, and this piezoelectric element driving circuit 30 is a sine having the same frequency as the resonance frequency of the diaphragm 28 attached to each piezoelectric element 29. A wavy drive signal is applied to each.
[0022]
The output end of the second fiber array 25 is attached to the fiber drive means 32 via the support member 31, and the fiber drive means 32 moves the support member 31 in the vertical direction as shown by the arrow in FIG. Moving. That is, the emission end of the second fiber array 25 arranged in the horizontal direction is scanned in the vertical direction orthogonal to the horizontal direction.
[0023]
Then, by applying a drive signal having a resonance frequency of the diaphragm 28 to the piezoelectric element 29 to which the diaphragm 28 is attached, the diaphragm 28 resonates and vibrates greatly. The piezoelectric element 29 side is fixed so as not to greatly vibrate via a braking member or the like, and therefore, the other end to which the light shielding plate 27 is attached vibrates greatly (vertically in FIG. 3A). 3A, the light emitted from the end of the first fiber 21i to the opposite second fiber 24i side is shielded as shown in FIG. 3A, while when the lowermost position is reached, As shown by the two-dot chain line, the light passes through.
[0024]
That is, when light is transmitted from each first fiber 21i to the opposing second fiber 24i side, the light is modulated at the resonance frequency of the diaphragm 28 disposed therebelow.
[0025]
Furthermore, since the end portion of the second fiber 24i that emits light is vibrated in the vertical direction (vertical direction) by the fiber driving means 32, a two-dimensional region can be coded by modulation by frequency. The light modulated at each frequency has a characteristic of amplitude modulation. A piezoelectric element 29 is provided for each diaphragm 28. However, the entire diaphragm is attached to one end of a common piezoelectric element, and a drive signal having the resonance frequency of all the diaphragms is applied to the common piezoelectric element. May be.
[0026]
An endoscope apparatus 14 of the first embodiment using this frequency modulation coding means 20 is shown in FIG. The endoscope apparatus 14 includes an endoscope 15 having an elongated insertion section 18, a light source apparatus section 16 a that supplies illumination light coded by frequency modulation to the endoscope 15, and a video signal that is decoded. Are composed of a video processor 16 having a built-in signal processing unit 16b and a display 17 for displaying a video signal.
[0027]
The endoscope 15 includes an elongated insertion portion 18 to be inserted into a body cavity, an operation portion 19a provided at the rear end of the insertion portion 18, and a universal cable 19b extending from the operation portion 19a. A connector provided at the end of the universal cable 19b can be detachably connected to the video processor 16.
[0028]
An illumination light transmission image guide 33a is inserted into the endoscope 15, and the incident end of the image guide 33a reaches the connector.
A frequency modulation coding means 20 is provided in the light source unit 16a so as to face the incident end of the image guide 34a.
[0029]
Then, the white light of the lamp 6A emitted from the driving power source from the lamp driving circuit 6B is incident on the frequency modulation coding unit 20 and passes through the frequency modulation coding unit 20 (by the frequency modulation coding unit 20). White light modulated by frequency is projected onto the incident end of the image guide 33a (through the projection lens 8 arranged on the output side).
[0030]
That is, the frequency modulation coding means 20 projects the white light from the lamp 6A on the incident end of the image guide 33a as a line-shaped light spot in the horizontal direction with a frequency modulated and sequentially scanned in the vertical direction. The projection light is transmitted by the image guide 33a, and further projected onto the subject side from the distal end surface attached to the distal end portion of the insertion portion 18 via the projection lens 33b.
[0031]
Accordingly, a line-shaped light spot is projected onto the subject, and the line-shaped light spot is projected so as to be sequentially scanned in a direction orthogonal to the line. An objective lens or condenser lens 34a is disposed adjacent to the projection lens 33b at the distal end, and an image of light reflected by the subject is incident on the distal end surface of the light guide 34b disposed at the imaging position.
[0032]
That is, the line-shaped light spot is reflected and superimposed on the tip surface of the light guide 34b. The light transmitted by the light guide 34b is emitted from the rear end face on the emission side fixed by the connector. The light guide 34b can be composed of a single fiber.
[0033]
Then, the light is condensed by a condensing lens 35a facing the rear end face, and is received by three photoelectric conversion elements 37R, 37G, and 37B through dichroic prisms 36R and 36G as optical color separation means. The dichroic prism 36R selectively reflects light in the red wavelength range and transmits light in other wavelength ranges. The dichroic prism 36G selectively reflects light in the green wavelength region and transmits light in other wavelength regions.
[0034]
Accordingly, light of red, green, and blue wavelength components in the multiplexed light spot on the distal end face of the light guide fiber 34b is incident on the photoelectric conversion elements 37R, 37G, and 37B, and is incident on the photoelectric conversion elements 37R, 37G, and 37B. It is converted into an electrical signal corresponding to the brightness of the wavelength component, and each signal is input to the frequency separation means 38a.
[0035]
The frequency separation means 38a is composed of three sets of frequency separation means. Each set of frequency separation means is composed of a filter group for separating the signal component of the resonance frequency of the diaphragm 28 used for frequency modulation by the frequency modulation coding means 20 for the input signal. Then, the signal components of each frequency are separated by the respective sets of frequency separation means for the light of the red, green, and blue wavelength components.
[0036]
By this separation, the signal intensity or brightness (luminance value) data of the red, green, and blue wavelength components at each line-shaped portion in the subject image is extracted.
[0037]
The extracted data can be arranged in an array of brightness data at positions corresponding to the line-shaped portions in the subject image according to the frequency used for the separation of the data. That is, it can be restored (decoded).
[0038]
The restored data is stored in the image memory as color signal data of R, G, and B, respectively, by a position address in the line direction, for example, a horizontal address.
[0039]
The frequency separation means 38a is connected to the timing controller 38c, and a timing signal synchronized with scanning in the direction orthogonal to the line is input from the timing controller 38c. With reference to this timing signal, the line-shaped light spot is detected. The separated data is stored as color signal data of R, G, B according to the position address in the line direction adjacent to the line direction in accordance with the appropriate moving pitch in the vertical direction.
[0040]
In the timing controller 38c, the fiber driving means driving circuit in the frequency modulation coding means 20 is connected to the timing controller 38c, and the fiber driving means driving circuit is synchronized with the timing signal from the timing controller 38c in the vertical direction of the fiber driving means 32. Control movement.
[0041]
In this way, data for one frame in the vertical direction is stored in the image memory. Then, the signals are sequentially input to the video signal synthesizing unit 38b along the line. The video signal synthesizing unit 38b synthesizes the input R, G, B color signal data together with the synchronization signal into a video signal and outputs it to the display 17, and displays the subject image in color on the screen.
[0042]
According to the present embodiment, since no electric element is provided in the endoscope 15, it is possible to prevent noise from being radiated to an external electric device or the like. In addition, mixing of external noise can be solved.
[0043]
For this reason, it is possible to display an endoscopic image with good image quality that is not affected by noise on the display 17.
In addition, when a solid-state imaging device such as a CCD is employed, complicated wiring work is required when connecting to a large number of signal lines and the like. In this embodiment, complicated wiring work is not necessary. Become.
[0044]
In the case of an optical endoscope that uses an existing image guide for image transmission, a light guide that transmits illumination light and an image guide are required, and the light guide needs to transmit sufficient illumination light. For this reason, a bundle of a large number of fibers is required, whereas in the present embodiment, the image guide 33a requires a bundle of a large number of fibers like the light guide. Can be made of a single fiber, so that the insertion portion 18 can be made much thinner.
[0045]
Further, in the present embodiment, in order to improve the resolution, it is necessary to increase the number of fibers of the image guide 33a, but there is an advantage that only one light guide 34b is required.
[0046]
In the case where the imaging device (FIG. 1 or more specifically, the video processor 16 in FIG. 4) for imaging is configured without using the endoscope 15, the imaging is performed without being affected by ambient ambient light. Can do. In other words, since external light usually contains commercial frequency components, almost all of the frequency components can be removed by the decoding means.
[0047]
For this reason, it is possible to obtain a subject image of a color with good color reproducibility at all times with little influence from outside light.
In the case of an endoscope, it is rarely affected by external light, but this effect is also obtained in the case of an endoscope 15.
[0048]
When the harmonic component of the external light is affected, the frequency used for modulation may be variably set so as not to overlap with the frequency band used for modulation. Further, the influence of external light may be eliminated or reduced by synchronous detection with an oscillator signal used for modulation.
[0049]
Next, frequency modulation coding means 20 'formed using an optical modulation plate will be described. Then, instead of the frequency modulation coding means 20 of FIG. 4, this frequency modulation coding means 20 ′ may be used to constitute the endoscope apparatus.
[0050]
As shown in FIG. 5, the light from the lamp 6 </ b> A is collected in a line shape by the condenser lens 41 and irradiated in the radial direction of the light modulation disc 43 that is driven to rotate by the motor 42. The motor 42 rotates at a constant speed by the application of a motor drive signal from the motor drive circuit 44, and the light modulation disc 43 whose center is attached to the rotation shaft 42a of the motor 42 also rotates.
[0051]
As shown in FIG. 6, the light modulation disc 43 is formed with a row of openings, that is, a row of openings 45 in the circumferential direction. The openings 45 are periodically formed so that the intensity of the transmitted light changes in a sine wave shape, and the frequency is set to be different when the positions in the radial direction are different.
[0052]
A projection lens 46 is disposed on the opposite side of the light modulation disc 43 so as to face the condenser lens 41, and on the projection side of the projection lens 46, on the optical axis of the projection lens 46 and the light modulation disc. An incident end of the tape-shaped fiber array 47 is disposed on a surface (horizontal plane) along the radial direction of 43, and the vicinity of the incident end is fixed by a fiber pressing member 48.
[0053]
The output end of the tape-shaped fiber array 47 is fixed to the upper surface of the support member 51 (the upper surface is a horizontal plane), and the output end of each fiber is fixed in a tape shape along the horizontal plane. 52 is attached.
[0054]
As shown in FIG. 5, the fiber driving means 52 moves the emitting end of the tape-shaped fiber array 47 together with the support member 51 as indicated by an arrow in the vertical direction perpendicular to the arrangement direction (horizontal plane) of the emitting ends of the fibers.
[0055]
As a specific example of the fiber driving means 52 shown in FIG. 5, a speaker 52A is shown in FIG. In addition, as shown in FIG. 7, a piezoelectric actuator 52B that vibrates and scans the emission end of the tape-like fiber array 47 in the vertical direction using a piezoelectric phenomenon may be used.
[0056]
A projection lens 8 is arranged opposite to the output end of the fiber array 47, and projects a light image of the output end of the fiber array 47 on the subject side.
Even when this light modulation disc 43 is used, it can be modulated by frequency in the same manner as when the diaphragm 28 is employed.
[0057]
In addition, when a lens (a convex lens) that is symmetrical with the light source is applied to the light modulation disc 43, there is diffracted light from the surrounding opening, and therefore, it is indicated by a two-dot chain line in FIG. Thus, it is preferable to arrange the slits S1 and S2 to prevent the influence. The present invention can also be applied to FIGS. 5 and 7 and FIG. 8 described later.
[0058]
In the above description, the lamp 6A is used as the light source. However, for example, a laser light source 55 may be used as shown in FIG. Since the spread of the beam of the laser light is small, in FIG. 8, the light modulation disc 43 is irradiated by the two convex lenses 55a and 55b via the beam expander 55 as an optical system for expanding the beam diameter, and the transmitted light side A single fiber array 56 is disposed in the center. Instead of the single fiber array 56, a tape-like fiber array 47 may be used.
[0059]
The fiber diameter of the single fiber array 56 is, for example, 30 microns. The other end of the single fiber array 56 is driven by the fiber driving means 32 shown in FIG.
[0060]
When performing color imaging with visible light, the laser light source 55 in FIG. 8 is, for example, one that emits light in each of the three primary colors, that is, red, green, and blue, and a dichroic mirror is used as the light with the convex lens 55b. What is necessary is just to project the light of each wavelength range of red, green, and blue on the incident end of the single fiber array 56 through the light modulation disk 43 by inserting between the modulation disks 43.
[0061]
In FIG. 9, an LED light source array 57 is used instead of the laser light source 55, and a condensing lens 58 is disposed in front of the light emitting surface of each LED. The single fiber array 56 is disposed on the transmitted light side.
[0062]
In this case, for example, each LED of the LED light source array 57 has a wavelength λ = 632.8 nm, the diameter of the condenser lens 58 is 30 microns, and the NA is 0.1. If LED light sources 57 that emit light with red, green, and blue wavelengths are sequentially arranged, color imaging is also possible.
[0063]
In FIG. 10, the light from the light source is transmitted through the single fiber array 59, condensed by the convex lens 60a that projects the light at the exit end of the single fiber array 59, and placed on the light modulation disc 43 disposed near the focal position. Irradiated and arranged so as to be incident on the single fiber array 56 as a parallel light beam by a convex lens 60b disposed on the transmitted light side.
[0064]
In addition, separation from harmonics can be achieved by using the following as the opening row of the light modulation disc 43. Basically, the size and the like of the aperture shape to be used may be obtained by Fourier analysis under conditions that do not generate harmonics. As a result, a specific numerical example may be as shown in FIG.
[0065]
For example, the angular velocity of the light modulation disc 43 is 1 [rad / sec], and a circular aperture row is arranged on a concentric circle whose radius is shifted by 30 microns. In this case, circular openings having a diameter of 15 microns are arranged on the circumference having a radius of 1 mm at equal intervals of an angle of 0.04918 [rad].
In the case of this aperture row, the transmitted light intensity is modulated to a frequency of 20.33 [1 / second].
[0066]
More generally, when the angular velocity of the light modulation disc 43 is 1 [rad / sec], the transmitted light intensity can be set to an arbitrary frequency by arranging circular openings on the concentric circumference so as to satisfy the following conditions. Can be modulated.
That is, in order to obtain a frequency of 20.33 × α [1 / second], the circular aperture diameter is 15 / α [micron], and the angle between adjacent apertures is 0.04918 / α [rad].
[0067]
The opening shape of the opening row may be a rhombus. In this case, a specific numerical example may be as shown in FIG.
For example, the angular velocity of the light modulation disc 43 is set to 1 [rad / sec], and the rhombus opening rows are arranged on the concentric circumference with the radius shifted by 30 microns. In this case, rhombus openings having a width of 50 microns and a height of 2 microns are arranged at equal intervals of 0.05 [rad] on the circumference having a radius of 1 mm.
[0068]
In the case of this aperture row, the transmitted light intensity is modulated to a frequency of 20 [1 / second].
More generally, when the angular velocity of the light modulation disc 43 is 1 [rad / sec], the transmitted light intensity can be set to an arbitrary frequency by arranging the rhomboid openings on the concentric circumference so as to satisfy the following conditions. Can be modulated.
[0069]
That is, in order to obtain a frequency of 20 × α [1 / second], the width of the rhombus opening is 50 / α [micron], and the angle between adjacent openings is 0.05 / α [rad].
[0070]
Next, a specific configuration of the endoscope apparatus according to the second embodiment of the present invention will be described.
As shown in FIG. 12, an endoscope device 61 includes an endoscope 62, a light source device unit 63 for supplying illumination light coded by frequency modulation to the endoscope 62, and a signal for decoding and synthesizing a video signal. The video processor 65 includes a processing unit 64 and a display 66 that displays a video signal.
[0071]
The endoscope 62 includes an elongated insertion portion 67 to be inserted into a body cavity, an operation portion 68 provided at the rear end of the insertion portion 67, and a universal cable 69 extending from the operation portion 68. A connector 70 provided at the end of the universal cable 69 can be detachably connected to the video processor 65.
[0072]
An illumination light transmission image guide (hereinafter simply referred to as an image guide) 71 is inserted into the endoscope 62, and the incident end of the image guide 71 reaches the connector 70. An imaging lens 72 is arranged in the light source device 63 so as to face the incident end of the image guide 71, and the light of the three-color light emitting diode array 73 is transmitted by the tape-like fiber array 74 by the imaging lens 72. Further, a line-shaped light spot array reflected by the movable mirror 75 that is oscillated in a rotating manner is incident on the incident end of the image guide 71.
[0073]
That is, the three-color light emitting diodes 73 (r) constituting the three-color light emitting diode array 73 that simultaneously emits light of the three primary colors of red (R), green (G), and blue (B) (where r = 1, 2,..., M) are driven by drive signals obtained by amplifying the oscillation outputs of the oscillators 76R (r), 76G (r), and 76B (r) having different oscillation frequencies by the light source drive circuit 77, respectively.
[0074]
In other words, as shown in FIG. 12, the red light emitting diode array portion of the three-color light emitting diode array 73 is driven by the red light emitting diode array driving unit 80R, and the green light emitting diode array portion is driven by the green light emitting diode array driving unit 80G. The blue light emitting diode array portion is driven by a blue light emitting diode array driving unit 80B. All oscillators are set so that their oscillation frequencies are different, and can be discriminated (separated and extracted) by frequency discriminating means on the signal processing unit 64 side.
[0075]
The three-color light-emitting diodes 73 (r) of the three-color light-emitting diode array 73 are arranged so as to oppose each other (to form a tape-like fiber array 74), and are incident on the incident-side end surfaces of the respective fibers. Then, the signals are transmitted through the respective fibers, and emitted from the other end surface, that is, the emission end surface to the movable mirror 75.
[0076]
The output ends of the tape-shaped fiber array 74 are arranged in a line in the vertical direction, for example, and the m light spots in the line shape emitted from the output ends of the tape-shaped fiber array 74 are driven by, for example, a motor 78 as a movable mirror driving means. The light is reflected by the movable mirror 75 that is oscillated in a rotational manner, and is incident by the imaging lens 72 so as to scan the vertical fiber array on the end face of the image guide 71 in the horizontal direction. The motor 78 is driven by a motor drive circuit 79.
[0077]
The light transmitted by the image guide 71 is projected onto the subject 82 via the illumination lens 81 from the emission end fixed to the distal end portion of the insertion portion 67, and a linear light spot is orthogonal to the line on the subject 82. Scanned in the direction.
[0078]
An objective lens or a condensing lens 83 is provided at the tip, and the reflected light of the light irradiated on the subject 82 is collected and a photoelectric conversion element 84 such as an avalanche photodiode having high sensitivity and a fast response speed. Is received.
[0079]
The photoelectric conversion element 84 has a photoelectric conversion function for a single pixel, and a signal photoelectrically converted by the photoelectric conversion element 84 is transmitted by a signal line 85 formed by a single coaxial line. The signal is input to the amplifier 86 constituting the signal processing unit 64 of the video processor 65, amplified, and then input to the frequency component separating means 87.
[0080]
This frequency component separating means 87 is, for example, a large number of filters (specifically, 3m band-pass filters having the frequency of each oscillator as a pass band or m band-pass filters are used by switching three times) or high-speed These are formed by fast Fourier transform means (FFT means) or the like that extracts the signal data of each frequency component by performing the Fourier transform process of the above, and separates the frequency components of the oscillator from the received signal. This separation operation is performed in synchronization with the horizontal scanning of the movable mirror 75 by a timing signal from the timing controller 88.
[0081]
The motor driving circuit 79 for driving the movable mirror 75 is connected to the timing controller 88 so that it can be performed in synchronism as described above, and the movable mirror 75 is moved via the motor 78 in synchronization with the timing signal from the timing controller 88. To drive.
[0082]
In other words, the frequency component separation means 87 can decode the position of the fiber in which the signal data separated by the frequency separation is emitted in the vertical direction, but in the horizontal direction (the time direction or time axis for the frequency component separation means 87). Since the direction is not identified, the horizontal position is separated or decoded with reference to the timing signal from the timing controller 88.
[0083]
Each signal separated by the frequency component separation means 87, specifically, R, G, B image signal data is input to the video signal synthesis means 89, the video signals are synthesized, and the subject image is displayed in color on the display 66. The
[0084]
According to the present embodiment, the endoscope 62 need only have a single photoelectric conversion element 84 and a signal line 85 connected to the photoelectric conversion element 84 as electrical elements. Since the signal line 85 can be formed by a single coaxial line, it is possible to use an outer diameter coaxial line that secures a strength that does not break the thin insertion portion 67.
[0085]
In addition, since the signal transmitted through the signal line 85 is a weak signal, even if it is radiated to the outside, it is unlikely to affect the external device as noise. In this embodiment, since the coaxial line is employed as the signal line 85, the function of the shield is enhanced, and the influence of radiating to the outside can be substantially ignored.
[0086]
In addition, since one coaxial line is inserted into the insertion portion 67 and the like in this way, even if it is used in a noisy environment, the inner conductor side on the inner conductor side by the shielding function by this coaxial line. It is possible to sufficiently reduce the mixing of noise.
[0087]
Therefore, according to the present embodiment, it is possible to reduce the noise radiated to the outside from the endoscope 62 to a state of virtually no noise, so that the influence on the external device can be eliminated.
[0088]
In addition, since external noise can be sufficiently reduced, it is possible to display an endoscopic image having a good image quality with little or no influence of noise on the display 66.
[0089]
Further, as described above, since the signal line 85 may be a single coaxial line, a signal line having a strength that does not cause disconnection can be used, and the occurrence of disconnection can be substantially eliminated.
In addition, when a solid-state imaging device such as a CCD is employed, complicated wiring work is required when connecting to a large number of signal lines and the like. In this embodiment, complicated wiring work is not necessary. Become.
[0090]
In this embodiment, the resolution can be improved by increasing the number of fibers of the image guide 71 corresponding to the light guide used in the case of an existing electronic endoscope in the insertion portion 67.
[0091]
FIG. 13 shows an endoscope apparatus 91 according to a first modification. This endoscope apparatus 91 is an endoscope 93 using a subject light transmission fiber 92 instead of the photoelectric conversion element 84 and the signal line 85 provided in the endoscope 62 in the endoscope apparatus 61 of FIG. Light collected by the objective lens or condenser lens 83 and incident on one end is transmitted to the other end on the connector 70 side. The subject light transmission fiber 92 may be a fiber that transmits light, such as a light guide fiber, and may be a single fiber.
[0092]
A condensing lens 94 is disposed opposite to the other end of the subject light transmission fiber 92, and the light emitted from the other end is condensed on the light receiving element 95. The light photoelectrically converted by the light receiving element 95 is input to the amplifier 86.
[0093]
As the light receiving element 95, for example, an avalanche photodiode or a photomultiplier can be used. Other configurations are the same as those in FIG.
The operation and effect are almost the same as those of the second embodiment. In addition to this, since this embodiment does not require an electrical element in the endoscope 93, noise is not given to the outside, and external noise can be prevented from entering.
[0094]
Further, in this modification, the subject light transmission fiber 92 can be basically composed of a single fiber, compared to an existing optical endoscope using an image guide. Compared with the existing optical endoscope, the number of fibers of the image guide 71 can be increased (the space vacated by the one fiber) to further improve the resolution.
In other words, the resolution can be improved more than in the case of an existing optical endoscope without increasing the diameter of the insertion portion.
[0095]
FIG. 14 shows an endoscope apparatus 97 according to a second modification. This endoscopic device 97 is the same as the endoscopic device 91 of FIG. 13, but instead of using the three-color light emitting diode 73 (r), a red light emitting diode array 73R composed of a red light emitting diode 73R (r) that emits red light, green A green light emitting diode array 73G composed of green light emitting diodes 73G (r) that emits light at blue and a blue light emitting diode array 73B composed of blue light emitting diodes 73B (r) that emit blue light are employed.
[0096]
In response to this change, three tape-like fiber arrays 74R, 74G, and 74B are employed instead of the one tape-like fiber array 74 used in FIG.
[0097]
Each red light emitting diode 73R (r) causes the oscillation output of the oscillator 76R (r) to emit light via the light source driving circuit 77, and each green light emitting diode 73G (r) drives the oscillation output of the oscillator 76G (r) to the light source. Light is emitted through the circuit 77, and each blue light emitting diode 73B (r) emits the oscillation output of the oscillator 76B (r) through the light source driving circuit 77.
[0098]
The light from each red light emitting diode 73R (r) is incident on the end face of one opposing fiber in the tape-shaped fiber array 74R, and is emitted from the other end to the movable mirror 75 side.
[0099]
The light from each green light emitting diode 73G (r) is incident on the end face of one opposing fiber in the tape-like fiber array 74G and is emitted from the other end to the movable mirror 75 side.
[0100]
Similarly, the light of each blue light emitting diode 73B (r) is incident on the end face of one opposing fiber in the tape-like fiber array 74B, and is emitted from the other end to the movable mirror 75 side.
[0101]
Note that the output end sides of the three tape-shaped fiber arrays 74R, 74G, and 74B are laminated so that three tapes are stacked. In this case, the red, green, and blue light emitted from the emission end is shifted by about the fiber pitch in the horizontal direction. Therefore, the frequency separation unit 87 separates each component in consideration of this shift.
[0102]
Other configurations are the same as those of the first modification of FIG. The second modification has almost the same operations and effects as the first modification. Further, by employing individual light emitting diodes, it is suitable for increasing the light output.
[0103]
FIG. 15 shows an endoscope apparatus 101 according to a third modification. This endoscope apparatus 101 is a modification of the structure of FIG. That is, the light source unit 102 corresponding to the light source device unit 63 of the video processor 65 and the video signal processing unit 103 corresponding to the signal processing device unit 64 are separated and the light received by the subject light transmission fiber 92 is received. And a measuring head 104 further separated.
[0104]
In accordance with this change, the rear end of the subject light transmission fiber 92 in the endoscope 93 in FIG. 14 is not inserted through the universal cable 69, but extends from the rear end of the insertion portion 67 to the rear side thereof. The endoscope 106 is disposed in the vicinity of the rear end, faces the rear end surface, and has a condenser lens 105 disposed at the rear end.
[0105]
A measuring head 104 is attached to a portion where the condensing lens 105 is disposed, and a condensing lens 107 and a light receiving element 108 such as a photomultiplier or an avalanche photodiode are incorporated in the measuring head 104.
[0106]
The output of the light receiving element 108 is input to an amplifier 86 in the video signal processing unit 103 via a signal line. The video signal processing unit 103 includes an amplifier 86, a frequency component separation unit 87, a timing controller 87, and a video signal synthesis unit 89.
[0107]
The other configuration is the same as that of the endoscope apparatus 97 of FIG. The operation and effect are almost the same.
[0108]
FIG. 16 shows an endoscope apparatus 111 according to a fourth modification. This endoscope apparatus 111 uses an endoscope 106 having the same configuration as that shown in FIG. Further, although the internal configuration is different, a light source unit 112, a video signal processing unit 113, and a measuring head 114 are provided as in FIG.
[0109]
The light source unit 112 employs a three-color light emitting diode array 73 as in the light source device unit 63 of FIG. 12, but outputs the output of the oscillator 76 (r) having a different frequency for each three-color light emitting diode 73 (r). The difference is that light is emitted through the drive circuit 77. That is, in this case, the same number of oscillators 76 (1),..., 76 (m) as the number of fibers of the tape-shaped fiber array 74 is used (in FIG. 12, 3 of the number of fibers of the tape-shaped fiber array 74). Double the number of oscillators).
[0110]
Therefore, in this apparatus 111, the three colors of the three-color light emitting diodes 73 (r) are modulated at the same frequency and projected onto the subject through the endoscope 106. For this reason, in the measuring head 114, the light condensed by the condenser lens 107 is separated into light of three colors by the two dichroic prisms 115 and 116, and the light of the separated colors is respectively received by the light receiving elements 108B, 108G, and 108R. It is receiving light.
[0111]
The dichroic prism 115 selectively reflects light of a blue wavelength and transmits light of another wavelength range, and the dichroic prism 116 selectively reflects light of a green wavelength and transmits light of another wavelength range. To do. Accordingly, blue, green, and red light components are incident on the light receiving elements 108B, 108G, and 108R.
[0112]
The signals photoelectrically converted by the light receiving elements 108B, 108G, and 108R are amplified by the amplifiers 86B, 86B, and 86R in the video signal processing unit 113, and then input to the frequency component separation means 87B, 87G, and 87R. .
The signal components separated by the frequency component separation means 87B, 87G, 87R become R, G, B image data and are input to the video signal synthesis means 89.
[0113]
Other configurations are the same as those in FIG. According to this device 111, the number of oscillators can be reduced. Other operations and effects are almost the same as those in FIG.
[0114]
In each of the above-described embodiments, a lock-in amplifier is used as a frequency separation unit, an oscillation signal of an oscillator used for modulation is used as a reference signal, and a signal of each frequency is photoelectrically converted by a photoelectric conversion unit. The signal component of each frequency may be separated and extracted by performing synchronous detection on the input signal).
In addition, embodiments configured by partially combining the above-described embodiments and the like also belong to the present invention.
[0115]
[Appendix]
1. In an endoscope apparatus that projects light onto a subject from the front end side of an elongated insertion portion, and enables observation of a subject image on the rear end side of the insertion portion via an objective optical system,
Projecting means for projecting a plurality of light spots whose emission intensities are modulated at a plurality of frequencies onto a subject;
A light receiving means for receiving reflected light of a plurality of light spots projected on the subject;
Frequency separating means for frequency separating the output of the light receiving means;
Detection means for detecting the brightness of the reflected light from the output signal separated by the frequency separation means;
An endoscope apparatus characterized by comprising:
[0116]
2. Appendix 1 wherein the projection means projects light spot light of three primary colors, and the light receiving means receives color separation means for separating each of the wavelengths of light of the three primary colors and light separated by the color separation means. It has a light receiving element.
3. Supplementary note 1, wherein the light receiving means is disposed at a distal end portion of the insertion portion.
4). Additional remark 1 wherein the light receiving means guides the reflected light to the rear end side of the insertion portion by means of a fiber transmitting light whose tip is disposed at the distal end portion of the insertion portion.
[0117]
5. Supplementary Note 4, wherein the reflected light is guided to the outside of the endoscope by the fiber, and is photoelectrically converted by a light receiving element disposed outside.
6). Supplementary note 1, wherein the frequency separation means is composed of FFT.
7). Supplementary Note 1, wherein the frequency separation means includes a plurality of narrowband filters.
8). Appendix 1 The frequency separation means includes synchronous detection means for performing synchronous detection in synchronization with a signal having a frequency used to modulate the emission intensity.
[0118]
9. In an imaging apparatus having illumination means for illuminating a subject and imaging means for imaging the illuminated subject,
Projection means for illuminating by projecting a plurality of light spots whose emission intensity is modulated at a plurality of frequencies onto a subject,
A light receiving means for receiving reflected light of a plurality of light spots projected on the subject;
Frequency separating means for frequency separating the output of the light receiving means;
Detection means for detecting the brightness of the reflected light from the output signal separated by the frequency separation means;
An imaging apparatus comprising:
[0119]
(Background to appendices 9-13)
A normal imaging apparatus has no illumination means or weak illumination, so that there is a problem that a subject image captured by external light is easily affected.
In order to solve this problem, the configuration of Supplementary Note 1 is adopted so that imaging can be performed while eliminating or reducing the influence of external light and the like. That is, it is possible to always obtain a reproducible subject image with almost no influence from outside light.
[0120]
10. Appendix 9 wherein the projection means projects light spots of three primary colors, and the light receiving means receives color separation means for separating the wavelengths of light of the three primary colors, and light separated by the color separation means, respectively. It has a light receiving element.
(Effect of Supplementary Note 10) A subject image having color reproducibility can always be obtained without being substantially affected by external light.
[0121]
11. Appendix 9 wherein the frequency separation means is composed of FFT.
12 Appendix 9 wherein the frequency separation means comprises a plurality of narrow band filters.
13. Appendix 9 wherein the frequency separation means includes synchronous detection means for performing synchronous detection in synchronization with a frequency signal used to modulate the emission intensity.
[0122]
【The invention's effect】
As described above, according to the present invention, an endoscope that projects light onto the subject from the front end side of the elongated insertion portion and allows the subject image to be observed on the rear end side of the insertion portion via the objective optical system. In the device
Projecting means for projecting a plurality of light spots whose emission intensities are modulated at a plurality of frequencies onto a subject;
A light receiving means for receiving reflected light of a plurality of light spots projected on the subject;
Frequency separating means for frequency separating the output of the light receiving means;
Detection means for detecting the brightness of the reflected light from the output signal separated by the frequency separation means;
Since it is possible to adopt a light receiving means that does not need to be driven by a high frequency drive signal, it is possible to substantially eliminate noise radiated to the outside even when a signal line is inserted into the endoscope, It is easy to shield noise from the outside, and an endoscopic image with good image quality can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the principle of the present invention.
FIG. 2 is a perspective view showing FIG. 1 with a more specific configuration.
FIG. 3 is a diagram showing a specific configuration of the spatial coding means in FIG. 2;
FIG. 4 is a configuration diagram of the endoscope apparatus according to the first embodiment of the present invention.
FIG. 5 is a side view showing a specific configuration of spatial coding means using a light modulation disc.
6 is a perspective view of FIG. 5. FIG.
7 is a perspective view showing a modification of the fiber driving means different from FIG. 6. FIG.
FIG. 8 is a side view showing a part of the first modification of FIG. 5;
FIG. 9 is a side view showing a part of the second modification of FIG. 5;
FIG. 10 is a side view showing a part of the third modification of FIG. 5;
FIG. 11 is a diagram showing a specific example of an opening row in a light modulation disc.
FIG. 12 is a configuration diagram of an endoscope apparatus according to a second embodiment of the present invention.
FIG. 13 is a configuration diagram of an endoscope apparatus according to a first modification of the second embodiment.
FIG. 14 is a configuration diagram of an endoscope apparatus according to a second modification of the second embodiment.
FIG. 15 is a configuration diagram of an endoscope apparatus according to a third modification of the second embodiment.
FIG. 16 is a configuration diagram of an endoscope apparatus according to a fourth modification of the second embodiment.
[Explanation of symbols]
1 ... Endoscopic device
2 ... Subject
3 ... Lighting part
4 ... Imaging unit
5. Image display means
6 ... Light source
7. Spatial coding means
8. Projection lens
9 ... imaging lens
10: photoelectric conversion means
11: Spatial decoding means
12 ... Video signal synthesis means
14 ... Endoscopic device
15 ... Endoscope
16 ... Video processor
17 ... Display
18 ... Insertion section
20: Frequency modulation coding means
22, 25 ... Fiber array
27 ... Shading plate
28 ... Diaphragm
29 ... Piezoelectric element
33a ... Illumination light transmission image guide
33b ... Projection lens
34a ... Objective lens
34b ... Light guide
36R, 36G ... Dichroic prism
37R, 37G, 37B ... photoelectric conversion element
38a ... Frequency separation means
38b ... Video signal synthesizing means
38c ... Timing controller

Claims (1)

In an endoscope apparatus that projects light onto a subject from the front end side of an elongated insertion portion, and enables observation of a subject image on the rear end side of the insertion portion via an objective optical system,
Projecting means for projecting a plurality of light spots whose emission intensities are modulated at a plurality of frequencies onto a subject;
A light receiving means for receiving reflected light of a plurality of light spots projected on the subject;
Frequency separating means for frequency separating the output of the light receiving means;
Detection means for detecting the brightness of the reflected light from the output signal separated by the frequency separation means;
An endoscope apparatus characterized by comprising:

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