JPH03165734A - Light source device for endoscope - Google Patents

Abstract

PURPOSE:To make the overall characteristics of light quantity control sharp and dispense with a rotary filter and a motor driving it by merging multiple light fluxes by a light emitting means into one light flux, and sending it out. CONSTITUTION:EL light emitting element groups 11R, 11G, 11B fed with the driving power by driving circuits 10R, 10G, 10B generate the illumination light of respective spectra. Individual illumination light is collected by a light collecting lens 12, and it is fed to a light guide 5 as the white illumination light to be radiated to an object to be photographed 6. An increase of the light on the photographed object 6 becomes an electric signal via a CCD 7, a control signal is outputted to a control circuit 9 from a video signal processing circuit 8, and control is performed to increase the light quantity if it is deficient and decrease the light quantity if it is excessive. The light quantity can be increased or decreased without using a throttle by a mechanical means, and the control with good response characteristic can be obtained. No rotary color filter and no drive motor are required for a face sequence photographing type endoscope light source device.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in light source devices for endoscopes.

[Prior Art] In recent years, scopes or fiberscopes have been widely used, which are capable of diagnosing and inspecting internal organs in body cavities by inserting an elongated insertion section into body cavities. . Moreover, it is used not only for medical purposes but also for industrial purposes to observe and inspect objects such as inside pipes of boilers, machines, chemical plants, etc., or inside machines.

Furthermore, electronic endoscopes using a solid-state image device such as a charge-coupled device (COD) as an imaging means are also used in various regions.

FIG. 6 shows an example of the configuration of the electronic endoscope device described above.

This electronic endoscope device is a field sequential imaging type electronic endoscope device, and includes, for example, an electronic endoscope (hereinafter referred to as an endoscope) 92 having an elongated insertion section for insertion into a body cavity. ,
An endoscope light source device that supplies illumination light to the endoscope 92 @(
(hereinafter referred to as a light source device) 91, a video processing device 93 that converts the electrical signal imaged by the endoscope 92 into a video signal, and a monitor 94 that displays an observation image using the video signal of the video processing device 93. It is made up of.

The light source device 91 is connected to a light source 82 that emits, for example, white illumination light, and is connected to the light source 82.
a lamp drive circuit 81 for driving the above-mentioned illumination light, an aperture 83 for increasing or decreasing the amount of illumination light; an aperture control circuit 86, and a rotary color filter 84 to which, for example, R, G, and B filters for dividing the aforementioned illumination light into wavelength regions of R (red), G (green), and B (blue) are attached. and a motor 85 for rotationally driving the rotating color filter 84.

The endoscope 92 has a CC which is a solid N image element at the tip.
D97 is disposed, and a light guide 95 made of, for example, a glass fiber bundle guides illumination light to the distal end of the endoscope 92.
A cable 97c and the like connected to the CCD 97 are provided inside. The light guide 95 has an incident end face facing the light source 82 via the aperture 83 of the light source device 91, and an output end face disposed at the tip of the inner diameter v192. The cable 97c has one end connected to the CCD 97 as described above, and the other end connected to the video signal processing device 9.
3 is connected to a video signal processing circuit 98 described later.

The video processing device 93 drives the CCD 97,
A video processing circuit 98 is provided which converts the electric signal from the CCD 97 into a video signal and outputs a control signal to the aperture control circuit 86. The CCD 97 is connected to the video processing circuit 98 by the cable 97c, the monitor 94 is connected to the video signal output end, and the aperture control circuit 86 is connected to the control signal output end.

In the electronic endoscope device configured in this way, the illumination light from the light source 82 turned on by the drive power of the lamp drive circuit 81 is adjusted to 1 lN by the aperture flil+control circuit 86.
As an appropriate amount of light by the aperture 83 that has been adjusted,
R with the rotating color filter 84 rotated by the motor 85.
, G, and B in the wavelength range of 111 series, and is supplied to the incident end face of the light guide 95.

The aforementioned illumination light is guided by the light guide 95 and irradiated onto the subject 96 and the like from the tip of the endoscope 92.

An image of the subject 96 is formed on the photoelectric conversion surface of the CCD 97 by an objective optical system (not shown). Said C
The CD 97 is driven by a video signal processing circuit 98. As a result, as described above, the image of the subject formed on the photoelectric conversion surface is photoelectrically converted and input into the video signal processing circuit 98 as an electrical signal.

The video signal processing circuit 98 performs various types of processing on the input electrical signal as described above and outputs it to the monitor 9 as a video signal.
Output to 4.

As a result, an image of the subject 96 is displayed on the monitor 94.

Further, the video signal processing circuit 98 determines the amount of illumination light irradiating the subject 96 from the input electricity (ffi V5) as described above, and controls the aperture control circuit 8.
A control signal is output to 6. This control signal controls the amount of light M to be increased if the amount of light described above is insufficient, and to decrease the amount of light M if the amount of light is in excess.

As a result, the diaphragm control circuit 86 controls the diaphragm 83 so that the diaphragm 83 is turned on if the amount of light is insufficient, and the diaphragm 83 is closed when the amount of light is excessive.

Thereby, illumination light is supplied so that the CCD 97 can properly take an image.

It should be noted that the above-mentioned electronic endoscope device uses a field sequential imaging method, and in the case of a simultaneous N image method, the rotating color filter 84 and the motor 85 are not provided, and for example, a unit cell of the CCD 97 is provided in front of the photoelectric conversion surface of the CCD 97. A filter that transmits R, G, and B wavelength regions corresponding to the above is provided.

By the way, as the above-mentioned light source, for example, the present applicant has proposed a light source device for an endoscope using a xenon light source in Japanese Patent Application No. 189455/1983.

This was done based on the fact that the xenon light source is a point light source and emits a large amount of light.

In addition to the above-mentioned xenon light source, a halogen light source or a metal halide light source is also used. moreover,
Some devices mainly use a xenon light source, and if the xenon light source fails, the other light sources mentioned above are used.

The above-mentioned xenon light source emits light by arc discharge, and as shown in Figure 7(a), the kick voltage (
If GJ is not within the power range that exceeds the interelectrode dielectric breakdown caused by (discharge starting voltage), no light will be emitted, and the total amount of illumination light will be proportional to the power, but this proportional condition is such that the total amount of illumination light will start emitting light.
If the value is not less than o, it cannot be applied, that is, it is not possible to emit light from LO to zero. However, as shown in Figure 7(b) 1, there is a characteristic that the color temperature of the illumination light does not change even if the power is increased at a power higher than the interelectrode dielectric breakdown caused by the kick voltage (discharge starting voltage). .

Furthermore, a halogen light source emits light by thermal radiation from a filament, and as shown in Figure 8(a), the relationship between the total amount of illumination light and the electric power is non-linear, and , as shown in Figure 8(b), the relationship between the color temperature of the illumination light and the power is non-linear, and in the case of a color image, when the power is changed and the total amount of illumination light is changed, the color changes. The reproducibility is not constant, and furthermore, the rate of change in the total amount of illumination light cannot follow the rate of change in power, that is, the response characteristics are extremely poor.

Therefore, as mentioned above, in a light source device using a xenon light source or a halogen light source, the total light amount is increased from zero,
In addition, it is necessary to keep the color temperature of the illumination light constant, so a mechanical diaphragm, such as a focus brain system or a multi-polar blade system, is used.

[Problems to be Solved by the Invention] However, all of the above-mentioned apertures using mechanical means have a tendency to be insatiable, and there is a problem in that the overall characteristics of light m control are not agile.

Furthermore, in the light source device of the electronic endoscope device using the field-sequential silver image method mentioned above, a rotating color filter and a motor for rotationally driving the rotating color filter are required. There is a problem in that the weight increases due to these factors.

The present invention has been made in view of the above-mentioned points, and does not use a mechanical diaphragm as a means for adjusting the increase/decrease in the amount of light as described above, and instead uses a rotating color filter as a light source device for an endoscope device using a frame-sequential imaging method. and to provide a light source device for an endoscope that does not use a motor to drive the rotating color filter [1]
It has been the target.

[Means for Solving the Problem] At least 6 or more light emitting means that emit light in a predetermined wavelength range by one or more EL light emitting elements having the same or slightly different emission spectra, and the plurality of light emitting means. and condensing means for condensing the luminous flux caused by the light and emitting it as one luminous flux.

[Function] With the above-described configuration, by condensing a plurality of light beams from the light emitting means into one light beam and emitting it, the overall characteristics of light m control can be made agile, and the rotary filter and the rotary filter can be driven. This makes the motor unnecessary.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 4 relate to a first embodiment of the present invention, in which FIG. 1 is an explanatory diagram showing the configuration of an electronic endoscope device, FIG. 2 is an explanatory diagram showing the configuration of a light source device, and FIG. 3 is an explanatory diagram showing the configuration of a light source device. [1] is an explanatory diagram showing the characteristics of illumination light from the light emitting element, and FIG. 4 is an explanatory diagram of the emission spectrum distribution of the illumination light.

As shown in FIG. 1, the electronic endoscope device includes, for example, an endoscope (hereinafter referred to as an endoscope) 2 having an elongated insertion portion for insertion into a body cavity; An endoscope light source device (hereinafter referred to as a light source device) 1 that supplies illumination light to an endoscope 2; an image processing device 3 that converts an electrical signal imaged by the endoscope 2 into a video signal; , and a monitor 4 that displays an observed image based on the video signal from the video processing device 3.

The light source device 1 includes an EL light emitting element group 11R that emits illumination light having wavelengths of R (red), G (green), and B (blue), for example.
, 11G, 11B, and this EL light emitting element group 11R, 11
G, 11B, and the [L light emitting element group 11R,
Drive circuits 10R and 10G that drive 11G and 11B,
10B, a control circuit 9 connected to the drive circuits 10R, 10G, and IOB and for controlling the drive circuits 10R, IOG, and 10B with control signals from a video processing circuit 8, which will be described later; and the EL light emitting element group 11R, A condensing lens 12 is provided to condense the illumination lights 11G and 11B.

The endoscope 2 has a CCD, which is a solid-state R image element, at its tip.
A light guide 5 made of, for example, a glass fiber bundle for guiding illumination light and a cable 7C connected to the CCD 7 are installed inside the endoscope 2. The light guide 5 has an entrance end face facing the condenser lens 12 of the light source device 1 and an exit end face disposed at the distal end of the endoscope 2 . One end of the cable 7C is connected to the CCD 7 as described above, and the other end is connected to a video signal processing circuit 8 of the video signal processing device 3, which will be described later.

The video processing device 3 includes a drive for the CCD 7 and a
A video processing circuit 8 and the like are provided which convert electrical signals from the CD 7 into video signals and output control signals to the control circuit 9. A cable 7 is connected to the video processing circuit 8.
C is connected to the C0D7, the video signal output terminal is connected to the monitor 4, and the control signal output terminal is connected to the control circuit 9 via the terminal 1T of the light source device 1.

The detailed configuration of the light source device 1 will be explained using FIG. 2.

The EL light emitting element group 11R includes EL light emitting elements 11R, 11R2, . . . , 11 that emit illumination light having an R (red) wavelength.
Ro and this E1 light emitting element 11R1, 11R2, . . . 1
The EL light emitting element group 11G includes EL light emitting elements 11G and 11G2 that emit illumination light having a G (green) wavelength.
．． ...11G and this EL light emitting element 11G,
11G1 2, ..., condensing lens 2 that condenses the illumination light of 11G.
1G, and the EL light emitting element group 11B is composed of B
EL light emitting element 11B that emits illumination light having a (blue) wavelength
, 11t32 , , 11B, and this EL
Light emitting elements 11B, llB2. ..., 11B, and a condensing lens 21B that condenses the illumination light of .

The operation of the endoscope light source device configured as described above will be explained.

The EL light emitting element group 11R to which drive power is supplied by the drive circuit 10R generates a single-spectrum R illumination light, and the EL light-emitting element group 11G to which drive power is supplied by the drive circuit 10G generates a single-spectrum G illumination light. The EL light emitting element group 11B, which generates illumination light and is supplied with drive power by the drive circuit 10B, generates B single-spectrum illumination light. This R,G.

The B illumination light is condensed by the condenser lens 12 and supplied to the incident end surface of the light guide 5 as white illumination light.

The aforementioned EL light emitting element groups 11R, IIG, and 11B will be explained using FIG. 2.

The E1 light emitting element group 11R includes EL light emitting elements 11R, 1
1R2,-, 11Ro, and a plurality of light beams having the same spectrum of R wavelength are collected by a condenser lens 2.
The light is condensed into one beam by 1R and output to the condenser lens 12.

The 131-light emitting element group 11G is the "L light emitting element 11G".
, 11G2.・The condenser lens 2 collects a plurality of light beams emitted by , 11Go and having the same spectrum of G wavelength.
The light is condensed into one beam by 1G and output to the condenser lens 12.

The EL light emitting element group 11B includes EL light emitting elements 11B,...
11B2. , 118n, the plurality of light beams having the same spectrum and the B wavelength are condensed into one light beam by the condenser lens 21B, and output to the condenser lens 12.

As described above, the three light beams emitted to the condenser lens 12 by the condenser lenses 21R, 21G, and 21B are condensed into one by the condenser lens 12, and as described above, the three beams are collected as white illumination light. The light is supplied to the incident end face of the light guide 5.

The aforementioned EL light emitting elements 11R, 11R2,...11R
, 11G, 11G2. ..., 11 Go.

1 1181.1182. As shown in FIG. 3 (a), the total amount of illumination light obtained by condensing the luminous flux of . .

In addition, the EL light emitting elements 11R1, 11R2,...11R
, 11G, 11G2.・, 11Go.

1 118. 11B2, . . . , 118o emits a single-spectrum luminous flux, and the color temperature and driving power of the illumination light that condenses this luminous flux are constant, as shown in FIG. 3(b). That is, the color temperature remains constant even if the driving power is changed.

Furthermore, the EL light emitting elements 11R1, 11R2,...11
R, 11G1.11G2.・, 11Go.

11B, 11B2, . . . , 11B, emit a single-spectrum luminous flux, and the spectral distribution of the illumination light that condenses this luminous flux is R,
This is a distribution of G and B single spectra.

The above-mentioned illumination light is guided by the light guide 5 and irradiated onto the subject 6 etc. from the tip of the endoscope 2, as shown in FIG.

An image of object light from the object 6 is formed on the photoelectric conversion surface of the CCD 7 by an objective optical system (not shown). Said CC
D7 is driven by the video signal processing circuit 8. As a result, as described above, the image of the subject formed on the photoelectric conversion surface is photoelectrically converted and input into the video signal processing circuit 8 as an electrical signal.

The video signal processing circuit 8 performs various processes on the input electrical signal as described above and outputs it to the monitor 4 as a video signal.

As a result, the image of the subject 6 is displayed on the monitor 4.

Further, the video signal processing circuit 8 determines the amount of illumination light irradiating the subject 6 from the electric signal input as described above, and outputs a control signal to the II+ control circuit 9. This control signal controls the amount of light to be increased if the above-mentioned amount of light is insufficient, and to decrease the amount of light if the amount of light ω is in excess.

Thereby, the control circuit 9 increases the driving power to the E1 light emitting element groups 11R, 11G, 11B by the drive circuits 10R, IOo, 10B if the amount of light is insufficient, and if the amount of light exceeds the amount of light. The drive circuits 10R, 10G
, 10B, the EL light emitting element group 11R, IIG, 1
The drive circuit 10R, so as to reduce the drive power to 1B.
10G.

10B.

As a result, white illumination light is supplied to the endoscope 2 so that the CCD 7 can appropriately take an image.

That is, the amount of illumination light can be increased or decreased without using a diaphragm by mechanical means, and furthermore, the inertial mass of the EL light emitting element is negligible, and control with good response characteristics can be achieved.

Next, a second embodiment of the present invention will be described, and the configuration is the same as that in FIGS. 1 and 2 of the first embodiment.
This will be explained using figures.

The control circuit 9 of this embodiment includes drive circuits 10R, 10G, 1
0B sequentially, and the drive circuit 10R110G, IOB
As a result, the EL light emitting element groups 11R, 11G, and 11B sequentially emit light, and illumination light, which is a single-spectrum R, G, and B light beam, is supplied to the endoscope 2 in time series.

Therefore, the present invention can be applied to a light source device of an electronic endoscope using a frame sequential imaging method.

That is, as a light source device for a field-sequential R-image type electronic endoscope, there is an advantage that a rotating color filter and a motor for driving the filter are not required.

Other functions and effects are similar to those of the first embodiment.

Next, a third embodiment of the present invention will be described, and the configuration is the same as that in FIGS. 1 and 2 of the first embodiment.
This will be explained using figures.

The video processing circuit 8 of this embodiment sends the color signal level (R, G, B) or color difference signal level (R-
A control signal of color information such as Y, B-Y) is output.

Thereby, the control circuit 9 controls the drive circuit 10R so that the white balance of the video signal is appropriate.

Controls 10G and 10B.

That is, there is an effect that white balance correction can be carried out in the control circuit 9.

Other functions and effects are the same as in the first and second practical examples.

FIG. 5 is an explanatory diagram of the emission spectrum distribution of illumination light according to the fourth embodiment of the present invention. The configuration is the same as that in FIGS. 1 and 2 of the first embodiment, and will be explained using FIGS. 1 and 2.

EL light emitting element 11R1°11R shown in FIG. 2 of this embodiment
,..., 11R, IIG, 11G2゜2
n 1..., 11G
, 11B, 11B2. ..., 11B1° emit light beams with slightly different spectra, and the spectral distribution of the illumination light that condenses these light beams is R', G'B', as shown in FIG. This is the distribution of the spectrum.

The above-mentioned illumination light is guided by the light guide 5 as shown in FIG. 1 and irradiated onto the subject 6 etc. from the tip.

That is, even if the subject is a fluorescent substance that is only excited in a specific spectrum, it can be detected, and furthermore, color reproducibility is improved.

Other functions and effects are similar to those of the first to third embodiments.

Note that the EL light emitting element group may be a single EL light emitting element.

Furthermore, a part or all of the EL light emitting element group and the condenser lens may be formed into a single structure.

Alternatively, the control circuit may be controlled within the light source device.

[Effects of the Invention] As explained above, according to the present invention, a rotating color filter and the rotating color filter are used as a light source device of an endoscope device d of a field sequential image transfer method without using an aperture of mechanical means. It becomes an endoscope light source 5A@ that does not use a driving motor, and the light ff1
This has the advantage that the response characteristics of l control are good and the color temperature can be easily adjusted.

[Brief explanation of the drawing]

1 and 2 relate to the first to fourth embodiments of the present invention, FIG. 1 is an explanatory diagram showing the configuration of an electronic endoscope device, and FIG. 2 is an explanatory diagram showing the configuration of a light source device. The explanatory drawings, FIG. 3, and FIG. 4 relate to the first embodiment of the present invention, and FIG.
FIG. 4 is an explanatory diagram showing the characteristics of illumination light from a light emitting element. FIG. 4 is an explanatory diagram of the emission spectrum distribution of illumination light. FIG. Figures 6 to 8 relate to the conventional technology;
7 is an explanatory diagram showing the characteristics of a xenon light source, and FIG. 8 is an explanatory diagram showing the characteristics of a halogen light source. 11R...E l-light emitting element group 11G...EL light emitting element group 11B...E light emitting element 1IY 12...Condensing lens

Claims (1)

[Claims] At least three or more light-emitting means that emit light in a predetermined wavelength range by one or more EL light-emitting elements with the same or slightly different emission spectra, and the light beams from the plurality of light-emitting means are condensed into one light beam. 1. A light source device for an endoscope, comprising: a condensing means for emitting light.