JP2843374B2 - Light source device for endoscope - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention detects a driving unit for driving the dimming diaphragm blade by an electric signal, and detects a position of the dimming diaphragm blade based on a change in magnetic flux density. The present invention relates to an improvement in an endoscope light source device provided with a detection unit.

[Prior art] In recent years, by inserting an elongated insertion portion into a body cavity,
2. Description of the Related Art Endoscopes (scopes or fiberscopes) capable of diagnosing and examining internal organs and the like are widely used. In addition to being used for medical purposes, it is also used for observing and inspecting an object in a pipe of a boiler, a machine, a chemical plant, or the like, or in a machine, for industrial use.

Further, various types of electronic endoscopes using a solid-state imaging device such as a charge-coupled device (CCD) as an imaging unit have been used.

The endoscope comprises, for example, an elongated endoscope that can be inserted into a body cavity, and a light source device to which a universal cord of the endoscope is connected by a connector. Further, the endoscope, which is an electronic endoscope, includes a video processor unit for converting an image pickup signal from an image pickup unit integrated with or separate from the light source device into a video signal, and an image of the video processor unit. A monitor for projecting a subject such as a body cavity portion is configured in accordance with the output.

The endoscope is provided with a light guide for guiding illumination light to a portion to be inspected or the like, and an incident end face of the light guide projects to a connector provided at an end of the universal cord. And is opposed to a light source provided in the light source device.

The light source of the light source device is, for example, an aperture blade, the light amount of the light source is adjusted, the light guide is guided,
It is radiated to the subject and the like from the distal end of the endoscope.

The present applicant has proposed a means for controlling the diaphragm blade in, for example, Japanese Patent Application Laid-Open No. 61-9628. In recent years, semiconductors for detecting magnetic flux density, such as Hall elements, have been put to practical use, and have come to be used for detecting the position of the diaphragm blade.

In this arrangement, as shown in FIG. 9, a magnet 71 is provided on an aperture blade 70, and a Hall element 72, a drive coil 74, and a dump coil 75 are provided near the aperture blade 70.

The output terminal of the Hall element 72 is a Hall element output amplifier 73.
Is connected to the input terminal of

One end of the dump coil 75 is grounded, and the other end is connected to the input terminal of the dump output amplifier 77.

The diaphragm (hereinafter referred to as the diaphragm drive) throttle drive output buffer which drives the blade 70 to the inverting input terminal 76, the output terminal of the dump output amplifier 77 via a resistor R _11, the hole through the resistor R ₁₂ the output terminal of the element output amplifier 73, the positive electrode of the aperture setting voltage Vref through a resistor Rref, and an output terminal of the narrowed drive 76 via a resistor R ₁₃ is connected.

The non-inverting input terminal of the diaphragm drive 76 is grounded, the output end of the narrowed drive 76 is connected to the inverting input terminal of the output end of the narrowed drive 76 via a resistor R ₁₃ as described above, the It is connected to one end of the drive coil 74.

The negative terminal of the aperture setting voltage Vref and the other end of the drive coil 74 are grounded.

The operation of the aperture blade driving circuit thus configured will be described.

When the aperture setting voltage Vref changes, the aperture drive 76
, The signal at the output of the aperture drive 76 changes. Therefore, the amount of excitation of the drive coil 74 changes, thereby changing the magnetic field generated by the drive coil 74, and the diaphragm blade 70 operates due to the correlation of the magnetic field with the magnet 71.

Due to the operation of the aperture blade 70, the magnetic field generated by the magnet 71 changes.
And the detection signal from the Hall element 72 is appropriately amplified by a Hall element output amplifier 73 to obtain a diaphragm blade position voltage as a position signal of the diaphragm blade 70. When the absolute value of the aperture blade position voltage and the aperture setting voltage Vref become equal, the aperture blade 70 stops.

The diaphragm blade 70 is provided with a dump coil 75 for detecting the operating speed of the diaphragm blade 70, and the dump coil 75 generates an electromotive force substantially in proportion to the speed of the movement of the magnet 71. Therefore, the larger the output signal of the aperture drive 76, that is, the faster the movement of the aperture blade 70, the greater the electromotive force,
The electromotive force is appropriately amplified by the dump output amplifier 77 and is input to the aperture drive 76 so that the output of the aperture drive 76 does not change rapidly.

[Problems to be Solved by the Invention] However, in the above-described control means of the diaphragm blade 70, the Hall element 72 not only changes the magnetic flux density of the magnet 71 but also generates a drive voltage applied to the drive coil 74. There is a problem that the magnetic flux generated by the coil 74 is also detected and an error occurs in the detection of the position of the diaphragm blade 70.

In particular, this problem is that, when a camera is attached to the endoscope eyepiece and a photograph is taken, the amount of light is instantaneously increased in order to irradiate the subject with a light amount suitable for the photographing.
In other words, it appears remarkably when the aperture blade is operated instantaneously.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an endoscope light source device that eliminates an aperture blade position detection error and improves the accuracy of aperture blade control.

Means and Action for Solving the Problems A light source device for an endoscope according to the present invention includes a dimming diaphragm blade having an integral magnet, and a magnetic field generated by an electric signal to form the dimming diaphragm blade. Driving means for driving, and detecting means for detecting a position of the dimming diaphragm blade based on a change in a magnetic flux density generated by the magnet provided on the dimming diaphragm blade, and a detection result from the detecting unit An endoscope light source device that controls the position of the dimming diaphragm blade by changing an electric signal applied to the drive unit based on the detection signal, wherein a detection signal obtained by the detection unit is applied to the drive unit A correction means for correcting based on an electric signal is provided.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

1 to 5 relate to an embodiment of the present invention. FIG. 1 is a block diagram showing a configuration of an endoscope apparatus, FIG. 2 is an explanatory diagram of a diaphragm unit, and FIG. 3 is a diagram of a diaphragm control circuit. Explanatory diagram,
FIG. 4 is a block diagram showing a configuration for displaying aperture control, and FIG. 5 is an explanatory diagram of a front panel of the light source device.

An endoscope apparatus includes an endoscope 1 using an image guide,
Light source device 11 connected by connector 8 of endoscope 1
And a camera 15 that can be attached to and detached from the eyepiece 9 of the endoscope 1.

The endoscope 1 includes, for example, an elongated and flexible insertion portion 2,
A large-diameter operation portion 6 connected to the rear end of the insertion portion 2 and a universal cord 7 extended to the side of the operation portion 6
And a connector 8 provided at an end of the universal cord. The insertion portion 2 includes a rigid distal end portion 3, a bending portion 4 continuously connected to a rear end of the distal end portion 3 and capable of bending up / down / left / right, for example.
And a long flexible flexible tube portion 5 connected to the rear end. The connector 8 is provided with an incident end face of a light guide 10 for guiding illumination light, and the light guide 10 is provided inside the universal cord 7, the operation unit 6, and the insertion unit 2, For example, an emission end face is provided on the tip end face. The operation unit 6 and the eyepiece 9 at the rear end
The eyepiece 9 is configured so that it can be observed with the naked eye and that a camera 15 can be detachably connected, for example.

The light source unit 11 includes a light source 12 internally provided with a xenon lamp or a halogen lamp for supplying illumination light to the light guide 10, and an aperture unit for dimming the illumination light to an appropriate amount.
13 and an aperture control circuit that controls and drives this aperture unit
It consists of fourteen.

As shown in FIG. 2, the aperture unit 13 includes an aperture blade driving / driving unit 21 described below, an aperture blade 22 described later,
The diaphragm blade 22 includes stopper pins 23a, 23b for preventing the diaphragm blade 22 from deviating from the rotation range, and damper rubbers 24a, 24b for protecting a contact portion between the stopper pins 23a, 23b and the diaphragm blade 22. The diaphragm blade 22 has a substantially disk-shaped member 22a formed with a substantially fan-shaped notch at a certain angle, and a substantially plate-shaped arm 22b formed at the rear of the substantially disk-shaped member 22c. Is formed, and the diaphragm blade drive unit 2
It is locked to one axis. The aperture blade 22 is provided integrally with a magnet 31 to be described later, and the aperture blade drive means 21 is provided with a coil to be described later for rotating the aperture by acting on the magnet 31. Have been. The magnet and the coil form a structure such as a rotary solenoid or a motor in principle. Damper rubber using a soft material such as rubber is provided on the outer circumferential surfaces of the stopper pins 23a and 23b in the longitudinal direction.
24a and 24b are provided, and the tamper rubbers 24a and 24b and the diaphragm blade 2 are provided on the outer circumferential surfaces of the damper rubbers 24a and 24b in the longitudinal direction.
Surface treatment is applied to prevent adhesion between the two. The drive signal line L ₁ , the dump signal line L _2, and the diaphragm blade position signal line L ₃ of the diaphragm unit 13 are connected to the diaphragm control circuit 14.

As shown in FIG. 3, the diaphragm unit 13 includes a drive coil 33 of the diaphragm blade driving means 21 for driving the diaphragm blade 22, a dump coil 34 for detecting a speed of the diaphragm blade 22, A hall element 32 for detecting a magnetic flux density of a magnet 31 provided on the aperture blade 22; and a hall element output amplifier 35 connected to the input end of the hall element 31 and amplifying an output signal of the hall element 32 as appropriate. It is composed of The drive coil 33 has one end connected to the drive signal line L _1, the other end is grounded. The dump coil 34 has one end connected to the dump signal line L _2, the other end is grounded. To the output terminal of the Hall element output amplifier 35, the diaphragm blade position signal line L ₃ is connected. The aperture unit 13 has a structure in which the magnetic permeability between the drive coil 33 and the Hall element 32 is unlikely to change.

Wherein the diaphragm control circuit 14, and the drive signal line L _1,
And the dump signal line L _2, and the aperture blade position signal line L _3,
The positive terminal of the aperture setting voltage source Vref via the resistor Rref, the H terminal for controlling the sample and hold, the S terminal for controlling the aperture with the sample and hold signal, and the signal line for detecting the proper exposure position were connected. A signal line connected to the F terminal, a control output terminal of a proper position detection circuit 50 for detecting a proper exposure position from the signal of the F terminal, and an A / D converter 51 for displaying an adjustment value at the time of adjustment. Is connected to the input terminal of The negative terminal of the aperture setting voltage source Vref is grounded.

The dump signal line L ₂ is connected to the input end of the dump output amplifier 36, the output end of the dump output amplifier 36 is connected to one end of a resistor R _1, which will be described later.

The diaphragm blade position signal line L ₃ is connected to an inverting input terminal of an inverting adder 37 via a resistor R _6, and a resistance described later.
It is connected to one end of R _2. The output terminal of the summing amplifier 37 is connected through a resistor R ₅ to the inverting input of the summing amplifier 37, the transfer terminal of the switch 40 (hereinafter referred to as T end), the A / D converter 51 Is connected to the input terminal of Further, R ₅ and R _6, has a resistance equal.

The non-inverting input terminal of the impedance converter 38 is connected to the make contact of the switch 40, one end of a capacitor C is connected, and the other end of the capacitor C is grounded. The output terminal of the impedance converter 38 is connected to the inverting input terminal of the impedance converter 38 is connected to the make contact of the switch 41 via a resistor R _3.

The control terminal of the switch 40 is connected to the aforementioned H terminal.

The break contact of the switch 41 is connected to the positive terminal of the aperture setting voltage source Vref via the resistor Rref.

The output terminal of the dump output amplifier 36 via the resistor R _1, and the diaphragm blades position signal line L ₃ via the resistor R _2,
The T end of the switch 41 is connected to the break contact of the switch 42 and to the break contact of the switch 43.

The make contact of the switch 43 is connected to the signal line connected to the above-mentioned F terminal, and the T end is connected to the make contact of the switch 42.

The aperture (hereinafter referred to as the diaphragm drive) drive the output buffer inverting input 39, a T terminal of the switch 42, the output end of the narrowed drive 39 via the resistor R ₄ is connected. The non-inverting input terminal of the aperture drive 39 is grounded.

The output terminal of the aperture drive 39 is a resistor as described above.
It is connected to the inverting input terminal of the narrowed drive 39 through R _4, and the drive signal line L _1, is connected to one end and the middle point of the variable resistor Rv. The other end of the variable resistor Rv is
Is grounded via a resistor R _7, it is connected to the non-inverting input of the summing amplifier 37.

The control terminals of the switches 41 and 42 are connected to the S terminal.

The control end of the switch 43 is connected to the proper position detection circuit 50.
Is connected to the control output terminal.

A diaphragm blade position voltage of the diaphragm control circuit 14 described later is
As shown in FIG. 4, the digital signal is input to an input terminal of an A / D converter 51 that converts an analog signal into a digital signal. The digital signal of the A / D converter 51 is processed by a CPU 52, for example, a microprocessor. 5, for example, a row of LEDs on the front panel 53 in which a number of LEDs are arranged in a row.
It is displayed by 54.

The operation of the thus configured endoscope light source device 11 will be described.

As shown in FIG. 1, the illumination light from the light source 12 of the light source device 11 is supplied to the entrance end face of the light guide 10 after the light amount is appropriately adjusted by the aperture unit 13. The illuminating light is guided through the light guide 10 and illuminates a subject or the like from an emission end face of the light guide 10 provided at the distal end portion 3 of the endoscope 1. The image of the subject illuminated by the illumination light is formed on the incident end face of the image guide by the objective lens disposed at the distal end portion 3, guided by the image guide, and disposed at the eyepiece 9. Observed by the eyepiece. Further, by attaching the camera 15 to the eyepiece 9, for example, it is possible to record a photograph or the like.

As shown in FIG. 2, the aperture unit 13 is controlled by an aperture control circuit 14 so that the aperture blade driving means 21 rotates the aperture blade 22 so that the aperture blade 22 moves from the damper rubber 24a to the damper rubber 24b. Between the aperture blades 22
The amount of illumination light is adjusted by blocking the incident end face of the equal light guide with a substantially fan-shaped notch formed in the member 22a.

Normally, as shown in FIG. 3, the diaphragm blade driving means 21 includes a resistor Rr via a break contact of a switch 41 and a T end.
a diaphragm set voltage Vref via ef, and the output voltage of the Hall element output amplifier 35 through a resistor R _2, the output voltage of the dump output amplifier 36 through a resistor R ₁ is, break contacts and T terminal of the switch 42 Is applied to the inverting input terminal of the aperture drive 39 via the. Also, at the inverting input terminal of the aperture drive 39,
The output current of the narrowed drive 39, the voltage at the inverting input terminal of the resistor R ₄ the narrowed drive 39 via the flows so that the zero.

Output current of the diaphragm drive 39 is adapted to flow into the inverting input terminal of the narrowed drive 39 via a resistor R ₄ as described above, it flows into the drive coil 33. Therefore, the drive coil 33 is excited, and the aperture blade 22 operates according to the correlation between the excitation of the drive coil 33 and the magnetic field of the magnet 31.

The operation of the aperture blade 22 changes the magnetic field of the magnet 31. An electromotive force is generated in the dump coil 34 due to the change in the magnetic field. This electromotive force is substantially proportional to the operation speed of the diaphragm blade 22, and the higher the operation speed of the diaphragm blade 22, the larger the electromotive force.
This electromotive force is amplified as appropriate by the dump output amplifier 36, the diaphragm through said resistor R ₁ as described above drives 39
Is applied so as to suppress the operating speed of the aperture blade 22.

Further, a change in the magnetic flux density of the magnetic field of the magnet 31 due to the operation of the aperture blade 22 results in a change in the output voltage of the Hall element 32, which is applied to the Hall element output amplifier 35, and is appropriately amplified by the Hall element output amplifier 35 and It is output as the blade position voltage.

The diaphragm blade position voltage of the Hall element output amplifier 35 is:
The polarity is opposite to the aperture setting voltage Vref,
When the diaphragm blade position voltage of the Hall element output amplifier 35 becomes equal to the absolute value of the diaphragm set voltage Vref, the diaphragm blade 22
Is stationary.

By the way, when the endoscope is used for visual observation, the illumination light is not rapidly increased or decreased.
When taking a picture using the camera, it is necessary to rapidly increase or decrease the illumination light to a short time of the automatic exposure setting time and the shutter time, which are the photographing time, in order to properly operate the automatic exposure (EE function) of the camera 15. There is. Furthermore, during the above-described photographing time, the illumination light must be stable, and the position of the aperture blade 22 must be precisely maintained. For this reason, during the shooting time, the position of the aperture 22 is set using the potentiometer voltage appropriately adjusted for the aperture blade position voltage of the Hall element output amplifier 35, as described later, instead of the aperture setting voltage Vref described above. There must be.

However, the change in the magnetic field detected by the Hall element 32 is:
Not only a change in the magnetic field due to the magnet 31 but also a change in the magnetic field due to the drive power of the drive coil 33 is detected. This, in order to cancel out the change in the magnetic field by the driving power of the drive coil 33, the diaphragm blade position voltage of the Hall element output amplifier 35, variable resistor Rv, resistors R _7, R _6, R ₅ and the summing amplifier 37 Must be adjusted so as to obtain the above-mentioned potential voltage.

In this adjusting method (adjustment mode), the arm 22b of the aperture blade 22 is fixed to a substantially intermediate position between the stopper pin 23a and the stopper pin 23b by, for example, mechanical means, and the aperture setting voltage Vref is adjusted to a maximum voltage and a minimum voltage. Voltage. Then, the output voltage of the inverting adder 37 at that time is input to the A / D converter 51, and is input to the CPU 52 by the A / D converter 51.
As described above, the CPU 52 controls the LED on the front panel 53
Column 54. At this time, since the aperture blade 22 is fixed, the magnetic field of the magnet 31 detected by the Hall element 32 is constant, but the output voltage of the inverting adder 37 changes. That is, the change in the output voltage of the inverting adder 37 depends on the drive coil detected by the Hall element 32.
33 due to the change in the magnetic field.

The current value of the driving power supplied to the drive coil 33 is proportional to the voltage value of the driving power except for a short transient period in which the supply of the power is started.

Therefore, the variable resistor Rv is appropriately adjusted so that the output voltage of the inverting adder 37 does not change. That is,
The diaphragm blade position voltage of the Hall element output amplifier 35 as described above, the applied with reversed polarity to the inverting input of the summing amplifier 37, suitably-divided voltage of the driving power by the variable resistor Rv and a resistor R ₇ By applying the voltage to the non-inverting input terminal of the inverting adder 37, the change in the magnetic field of the drive coil 33 is changed to a potentiometer voltage that cancels out.

This potentiometer voltage is charged to the capacitor C by a switch 40 which is turned on by a sample hold control described later, and is held (held) by the capacitor C when the switch 40 is turned off. Note that the impedance converter 38 functions as a voltage follower amplifier circuit having a high input impedance and a low output impedance.

The aperture control circuit 14 adjusted in this way, for example, a camera
The control of the aperture 22 in the case of taking a photograph by 15 will be described.

When a shooting sequence start signal (shooting notice signal) is input to the light source device 11 from the camera 15,
U52 is a switch 4 via the H terminal of the aperture control circuit 14.
A control signal is output to 0, and the switch 40 is turned on. Thus, the sampling of the potentiometer voltage described above is started. At the same time, the CPU 52 switches the switches 41 and 42 via the S terminal, that is, the switches 41 and 42 have their T ends switched to the make contact side. Further, when the proper position detecting circuit 50 is reset, the switch 43 is switched by the control signal of the proper position detecting circuit 50.
The end is switched to the make contact side and connected to the F terminal.

Thereby, at the inverting input terminal of the aperture drive 39,
A proper exposure position detection voltage described later is applied. The appropriate exposure position detection voltage is a voltage obtained by comparing an exposure level voltage (signal) from the camera 15 with a reference voltage from the CPU 52 by, for example, a comparator (not shown). The voltage value changes so as to match. That is, the aperture blade 22 is driven so that the exposure level becomes appropriate.

In addition, the above-mentioned matching of the voltage values of the exposure level voltage and the reference voltage, that is, the light amount of the appropriate exposure level,
The switch 43 is restored by the control signal of the proper position detection circuit 50, that is, the switch 43 is restored, that is, the T end of the switch 43 is switched to the break contact side.

At the same time, the CPU 52 turns off the switch 40 via the H terminal,
That is, the potentiometer signal is held (held).

Therefore, at the inverting input terminal of the aperture drive 39,
Through the T end and make contact of the switch 42, the output voltage of the Hall element output amplifier 35 through a resistor R _2, via the output voltage of the dump output amplifier 36 through a resistor R _1, a resistor R ₃ Impedance The output voltage of the converter 38 is applied. Here, since the diaphragm blade 22 is stationary, the output voltage of the dump output amplifier 36 can be ignored. Further, the output voltage of the impedance converter 38 is the Hall element output amplifier.
This is a sampled and held potentiometer voltage whose polarity is opposite to that of the diaphragm blade position voltage of 35.Therefore, the diaphragm blade position voltage of the Hall element output amplifier 35 is used as a servo circuit so that the absolute value of the potentiometer voltage becomes equal. Works.

Further, when a shooting sequence end signal (shooting completion signal) is input from the camera 15 to the light source device 11, the CPU 52 causes the switch 41 and the switch 42 via the S terminal.
To restore. That is, the aperture control circuit 14 is in a state where the endoscope 1 described above is used for visual observation.

That is, the potentiometer voltage is corrected by the drive power (voltage) of the drive coil 33, and the accuracy of the stationary position of the diaphragm blade 22 is improved. In a camera detachably connected to the eyepiece of the endoscope, Exposure (EE) may be performed. Using this automatic exposure level (hereinafter referred to as EE level)
Displays whether the photograph can be taken without fail. However, when the light amount of the luminous flux of the subject is insufficient due to the distance from the subject or the aperture being too narrow, etc., the amplification degree of the amplifier that amplifies the EE level increases, so that appropriate automatic exposure can be performed. difficult. Therefore, as shown in FIG. 6, the EE level is taken into, for example, a CPU, and the automatic exposure (EE) is performed.
If the value is an EE level (α) that is not possible, “Under (insufficient exposure)” is displayed. Also, it is uncertain whether the automatic exposure (EE) is possible. In some cases, "near under (exposure undefined)" is displayed. If the EE level allows automatic exposure, the CPU
As in the prior art, the aperture amount is taken in, and the automatic exposure (EE) is performed by calculating from the aforementioned EE level and the aperture amount.

Further, as described above, the damper rubbers 24a and 24b are subjected to a surface treatment for preventing adhesion with the diaphragm blade 22, but in consideration of a case where the surface treatment is reduced due to aging. From the state shown in FIG. 7 (a) where the aperture blade 22 is in contact with the damper rubber 24a when the power is not turned on,
When the power of the light source device 11 is turned on, as shown in FIG. 7B, the aperture blade 22 is moved to an intermediate position between the damper rubber 24a and the damper rubber 24b. Further, as shown in FIG. 8, for example, the CPU moves the diaphragm blade 2 to the intermediate position described above.
2 moves to the position of the diaphragm blade set in the memory or the like when the light source device 11 was used last time.

[Effects of the Invention] As described above, according to the present invention, when the light amount of the light source is instantaneously changed, the position of the aperture blade is appropriately controlled, and an effect such that reliable photography can be performed. is there.

[Brief description of the drawings]

1 to 5 relate to one embodiment of the present invention, and FIG.
FIG. 2 is a block diagram showing a configuration of the endoscope apparatus, FIG. 2 is an explanatory diagram of an aperture unit, FIG. 3 is an explanatory diagram of an aperture control circuit, and FIG. 4 is a block diagram showing a configuration for displaying aperture control. , FIG. 5 is an explanatory view of the front of the panel of the light source device, FIG. 6 is an explanatory view of automatic exposure (EE) control of the camera, FIG. 7 and FIG.
FIG. 9 is an explanatory diagram of the blade control when the power of the aperture light source device is turned on, and FIG. 9 is an explanatory diagram of an aperture control circuit according to a conventional example. 11 Light source device 13 Aperture unit 14 Aperture control circuit

Claims (1)

(57) [Claims] 1. A dimming diaphragm blade integrally having a magnet; a driving means for generating a magnetic field by an electric signal to drive the dimming diaphragm blade; and a driving means provided on the dimming diaphragm blade. Detecting means for detecting a position of the dimming diaphragm blade based on a change in a magnetic flux density generated by a magnet; and changing an electric signal applied to the driving means based on a detection result from the detecting means to perform the light adjustment. An endoscope light source device for controlling a position of a light diaphragm blade, wherein a correction means for correcting a detection signal obtained by the detection means based on an electric signal applied to the driving means is provided. Light source device for endoscope.