JPS6113236A - Light source device for endoscope - Google Patents

Abstract

PURPOSE:To take always correct endoscopic pictures by leading the illuminating light, which is adjusted with a diaphragm, into an endoscope and displaying the defect of exposure when EE data of a received light taken from the endoscope exceeds a prescribed level. CONSTITUTION:A camera 16 for endoscope is set to an eyepiece part of an endoscope 14 provided with an image guide 10 and a light guide 12, and pictures in body cavities are taken through the image guide 10. The light inputted to the camera 16 is divided into two by a splitter 18, and one is led to a film 20, and the other is converted photoelectrically by a photodetector 22 to perform light measurement. A control circuit 34 controls a stop 30 and a shutter 32 in accordance with data from photometric circuits 24 and 38, and under-exposure is displayed on a display part 39 and exposure of the film 20 is not performed if the EE signal from the photometric circuit 24 exceeds a prescribed level. Thus, pictures in body cavities of correct exposure are always taken.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a light source device for an endoscope, and particularly to a light source device for an endoscope having an automatic exposure function.

[Prior art] A transendoscopic imaging device is equipped with an automatic exposure function.
In this case, exposure calculation, ie, EE calculation, is performed by a CPU provided in the light source device.

This EE calculation is performed at a constant cycle, for example, 100 a+sec, based on the light reception signal corresponding to the illumination light before photographing, and the results indicate whether the exposure is appropriate, overexposure, underexposure, etc. Normally, in transendoscopic II true imaging, the aperture of the light source device is fully opened to make the shutter speed as fast as possible, but in transendoscopic diagnosis, the aperture is automatically or manually controlled to ensure that the illumination light is as desired. The brightness is adjusted. Therefore, since the result of exposure calculation before photographing is influenced by the aperture value, it is calculated by converting it into the value of the I11 shadow state.

In other words, the exposure is calculated so that the aperture is fully open and the lamp light intensity is large. Therefore, when the aperture 9 value is small, the converted magnification becomes very large. Also, if the aperture value is set small during manual inspection and the distance to the subject is large,
The light receiving signal level obtained from the light receiving element is very small.
Such signals are greatly affected by the writing conditions of the photodetector, photometric circuit, preamplifier, etc., such as noise.

For example, the received light signal may be buried in noise.

If exposure calculations are performed under such signal conditions, the calculation results will be unreliable, and even if the exposure status is displayed based on the calculation results, it will be meaningless, and will instead confuse the operator and cause shooting failures. It turns out to be a problem. In addition, as mentioned above, exposure calculation is performed every i Q Q 1 sec, but performing meaningless exposure calculations that result in incorrect results as described above will reduce the work efficiency of the CPU, and the computer control Unfavorable.

[Objective] Therefore, an object of the present invention is to provide a light source device for an endoscope that can obtain reliable exposure calculation results without unnecessary calculation processing.

[Overview] According to this invention, a light source that generates illumination light to be sent to an endoscope, an aperture provided in front of the light source for adjusting the amount of illumination light emitted from the light source, and a calculation circuit that performs exposure calculation. is provided. E corresponding to the light reception signal from the endoscopic camera
If the E data is below the cutting level corresponding to the noise level, the exposure calculation circuit will not calculate the exposure based on the EE data, and underexposure will be displayed.

[Example] In FIG. 1, an image guide 10, a light guide 1
An endoscope camera 16 is attached to the eyepiece of an endoscope 14 having an endoscope 14, and photographs an image inside the body cavity via an image guide. Light beam splitter 18 incident on camera 16
The light is divided into two parts, and one enters the film and the other enters the light receiving element 22. The light receiving element 22 photoelectrically converts the incident light and inputs it as a voltage signal to the photometry circuit 24. The light guide 12 of the endoscope 14 is guided to a light source device 26.

The light emitted from the light source lamp 28 of the light source device 26 is guided to the light guide 12 via an aperture 30 and a shutter 32.

The light source lamp 28, the aperture 30, and the shutter 32 are the control circuit 3.
4, and this control circuit 34 includes a photometric circuit 2.
4 outputs are provided. Shutter 32 is a patent application filed in 1986-1.
30152 (light source lamp 28
(blocking the passage from the light guide 12 to the light guide 12), the light from the light source lamp 28 is guided to the light receiving element 36.

Like the light receiving element 22, the light receiving element 36 converts the incident light into a voltage signal by photoelectric conversion and inputs the voltage signal to the photometry circuit 38. The output of this photometric circuit 3B is also input to the control circuit 34. Further, a display section 39 is connected to this control circuit 34 .

According to the block circuit shown in FIG. 2, the CPU 40, ROM 42, RAM 44, variable frequency oscillator 46, programmable peripheral interface (PPI) 48, programmable interno deaf counter (PIG) 50, and I10 are connected via path lines. Boats 52 are connected to each other. The variable frequency oscillator 46 is CP LJ 4
Continuously generates pulses of a predetermined frequency under the control of step 6.
Ru. The output of this variable frequency oscillator 46 is output from the photocoupler 5
4 to a frequency/voltage (F/V) converter 56, where it is converted into a voltage signal. The output of F/V converter 56 is connected to a first output of comparator 58.

The output of the photometric circuit 24 of the camera 16 is input to a switch 62 via an amplifier 60. The switch 62 and the switch 64 constitute a multiplexer 65, and one of the switches 62 and 64 is closed by a control signal from the PPI 48 supplied via a photocoupler 68. The switch 64 is supplied with an output voltage signal from a potentiometer 66 that detects the aperture value of the aperture 30.

The signal via either switch 62, 64 is provided to comparator 58. The output of this comparator 58 drives the aperture 30 via a driver 67. The outputs of amplifier 60 and potentiometer θB are led to switches 70 and 72, respectively.

The output of the photometric circuit 38 is passed through an amplifier 74 to a switch 76.
supplied to Switches 70, 72, and 76 constitute a multiplexer 77, and switching is controlled by the P P I 4B l1lill signal supplied via a photocoupler 78. The output of any one of switches 70.12.76 is input to a voltage/frequency (V/F) converter 80. The V/F converter 80 responds to a V/F conversion start signal from the PPI 48 via the photocoupler 82 and outputs a pulse signal with a frequency corresponding to the input voltage.

This pulse signal is sent to the photocoupler 84, inverter, 8G
It is input to the negative logic clock input terminal CLK of PIG5G via. A gate signal is input from the PPI 48 to the gate end of the PIG5G. The output of the I10 boat 52 is connected to the display unit 39 via a driver 88.

Next, the operation of the light source device for an endoscope will be explained.

In this light source device, manual mode and auto mode can be selectively set. You can also set an exposure check mode. Switch 6 when in manual mode
2 is turned off, and switch 64 is turned on. In this state, aperture data is input to the variable frequency oscillator 46 by inputting an aperture value using a keyboard (not shown), for example. This oscillator 46 generates a pulse signal of a frequency corresponding to the aperture data. This pulse signal is input to the F/V converter 56 via the photocoupler 54, converted to a voltage signal, and input to the comparator 58. On the other hand, the aperture data of the potentiometer 66 is transmitted to the comparator 58 via the switch 64.
The comparator 58 inputs an output signal corresponding to the difference between the two aperture data to the driver 61.

The driver 61 drives the aperture 30 in accordance with the data difference, and the output of the potentiometer 66 changes accordingly, and when it matches the input aperture data, the difference 30 is set to that value.

This allows manual dimming.

In the auto mode, the switch 62 is turned on and the switch 64 is turned off. In this state, the aperture data determined by the CPU 40 and the metering aperture of the camera 16, path 2
6, amplified by an amplifier 60, and passed through a switch 62, the EE data is input to a comparator 58.

The comparator 58 inputs an output signal corresponding to the difference between the aperture data and the EE data of the camera 16 to the driver 67.

The driver 67 drives the aperture 30 according to the data difference, thereby performing automatic light adjustment.

In the check mode, exposure check is performed using data in the multiplexer 77 circuit system.

This exposure check will be explained based on the flow shown in FIGS. 3A and 3B. 5TART is checked to see if a signal has been received from the camera 16. This is to check whether the camera is of a type that can display exposure values. If YES, it is checked whether the AUTO key is set, that is, automatic exposure mode. In the automatic exposure mode, the switch 62 is turned on and the switch 64 is turned off.

At this time, EE data from the camera 16 is input to the comparator 58, and the light source enters automatic light control mode. In multiplexer 77, switches 70, 76 are turned off and switch 72 is turned on. Therefore, the aperture data obtained by the potentiometer 66 is taken into the memory, that is, the RA.
It is stored at a predetermined address in M44. Next, switch 10 is turned on and switches 72 and 76 are turned off. At this time, the EE data via the amplifier po is taken in and stored at a predetermined address in the memory (RAM 44).It is checked whether the main lamp is on, and if the answer is No, the variable is set to (JNDER, which indicates YES). The EE data is compared with the cut-off data, that is, the data whose value is sufficiently larger than the noise level and the offset level.If the EE data is smaller than the cut-off data, the variable is
fart! DER is set and the process moves to flow 20. If EE is larger than the cutting data, that is, the determination is No, the exposure amount is calculated according to the following formula.

L=EEx255/IRl5xK.

However, IRIS - aperture ii, 255/IRIS = aperture opening (255/255 = aperture fully open, 25510 = fully closed), KO - overexposure system conversion constant - FLS (20) x minimum shift time (201 sec ) x minimum aperture value (1/
20), FLS is the flash magnification, i.e. 20 m5ec
This indicates how many times the amount of flash light is the amount of illumination light.

In the result of the above calculation, L is 0VER value, for example +1
- If it is greater than 5EV, the variable is set to 4, representing 0VER. If L is less than +1.5EV, Ne
ar -0VER=+0 - Checked to see if it is greater than 5EV. If YES, 3 representing N-0VER is set. If NO, the process moves to flow 30. In this flow 30, the underexposure amount is calculated using the following formula.

L-==, EEx255/IRl5xKuKLI-under system conversion constant-FLS (100) x maximum flash time (100m5ec) x maximum aperture value (1), final IL
ltN-tJNDERJ: It is determined that the value is large, and if the determination is YES, 2 representing OK is set, and if the determination is NO, 1->UNDER=-1·5EV is determined. If the determination is No, O representing LINDER is set, and Y
If it is ES, 1 representing N-LJNDER (--0.5EV) is set.

When the variables O to 4 are set as described above, it is determined whether this variable is the same as the previous time. If YES, the variable is sent to camera 16. In the camera, the variables are 0゛, 1.
It is determined whether the value is 2.3, and if it is 0, an under display is performed, and if it is 1, a near under display is performed. O if the variable is 2
K, that is, appropriate exposure is displayed. If the variable is 3, a near over is displayed; if it is not 3, an under is displayed.

Next, the case of close-range photography will be described with reference to the flowchart in FIG.

In the case of this close-range photography, the aperture value # at the time of photography is calculated from the current aperture value # and the EE level so that the shutter speed at the time of photography is 201 seconds. The basic formula for this calculation is shown below.

r-EExFLS (20)x255/IRISx 2
0 *5ecx x/ 255 x-rX IRIs/EExFLS (20)X1/
20 r: (mVms) Appropriate exposure amount (±0EVt-100
(mVms) EEL (mV) Current EE level FLS (T): TmS flash magnification IRIS: Current aperture value # It is determined whether or not the aperture value is greater than or equal to the minimum aperture value, and if No, the minimum aperture value is set. If x≧the minimum aperture value, it is determined that X≦the maximum aperture value. If No, the maximum aperture value is set.

By determining the aperture for close-range photography as described above, it is possible to take a photograph with an appropriate amount of exposure even in close-range photography.

Effects of invention 51! ] As explained above, according to the present invention, if the EE data input from the camera is below the cut-off level, the exposure amount is not calculated and underexposure is displayed, so the EE data buried in noise is used for exposure calculation. Since there are no errors and only accurate calculation results are always calculated, exposure control is reliable and appropriate transendoscopic photographs can always be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an endoscope system using an endoscope light source device according to an embodiment of the present invention, FIG. 2 is a block circuit diagram of the main parts of the endoscope system shown in FIG. Are Figures 38 to 3B part of Figure 2? j! FIG. 4 is a flowchart for explaining the operation of the mirror light source device, and FIG. 4 is a flowchart for correcting close-up photography. 14... Endoscope, 16... Endoscope camera, 22...
... Light receiving element 24 ... Photometry circuit, 26 ... Endoscope light source device, 30 ... Aperture 32 ... 9 shutter, 36
... Light receiving element, 38... Photometry circuit, 65.77...
・Multiplexer, 66... Potentiometer 40・
...CPU, 42...ROM144...RAM. Applicant's agent Patent attorney Atsushi Tsuboi Engraving of the drawing (no changes to the content) Figure 1 Figure 4 Manabu Shiga, Commissioner of the Patent Office 1, Indication of the case Patent application No. 133801/1989 2, Name of the invention included Mirror light source device 3, person making the amendment Patent applicant name (037) Olympus Optical Industry Co., Ltd. 4, representative application form (= engraving of the first attached drawing, as shown in the attached sheet) (Contents C2 No changes) ) Procedural amendment 1986, 60. Field, 24th, Director General of the Patent Office, Michibe Uga, 1, Indication of the case, Japanese Patent Application No. 133801/1983, 2, Name of the invention, Endoscope light source device 3, Person making the amendment, case Relationship with Patent applicant (037) Olympus Optical Industry Co., Ltd. 4, Agent No. 17 Mori Building 6, 1-26-5 Toranomon, Minato-ku, Tokyo.
Specification subject to amendment j domain pair, contents of amendment (1) In the 16th line of page 2 of the specification, the word "sho" is corrected to "sho". (2) “On film” on page 4, lines 6 and 7.
The text has been corrected to read "Film 20." (3) In the 4th line of page 7, the phrase "In the first light source device" is corrected to "In the aperture of the light source device." . (4) In the 5th and 6th lines of page 7, the phrase "Also, there is an exposure check mode" is corrected to "Also, when performing automatic exposure in each mode, the exposure check mode is also available." . (5) In the 11th line of page 8, the phrase "in check mode" is corrected to "in exposure check mode." (6) From the 11th line of page 8 to the 2nd line of page 9, the phrase ``Automatic exposure mode...becomes automatic light control mode'' has been replaced with ``If it is exposure check mode, the following Execute. In other words, ” is corrected. (7) On the 7th line of page 9, the phrase ``Switch 70 is turned ON and switches γ2 and γ6 are turned OFF'' was replaced with ``
Switches 72 and 76 are turned OFF and switch 10 is turned OFF.
"I'll be given an N," he corrected. (8) In the 9th line of the 9th page of the same page, correct "r(RAM44's)" to "r(RAM44)". (9) In the 9th line of the 11th page of the same page, "Under display... If the display is ``, it is rUNDER display, and if it is 1, it is N-U.
"NDER display" is corrected. (10) lx = r in the 1st and 2nd lines of page 12
xIRIS/EExFLS (20) xl /20J is rx=rx I RIs/[EExFLS (
20)x1/20]J.

Claims (1)

[Claims] a light source means for generating illumination light to be sent to the endoscope; a diaphragm means for adjusting the amount of illumination light from the light source means;
An endoscope comprising means for capturing EE data corresponding to a light reception signal from an endoscope camera, and means for displaying poor exposure without performing exposure calculation when this EE data exceeds a predetermined level range. photoelectric device.