JP3431295B2 - Aperture control device for endoscope light source device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an endoscope in which a movable diaphragm capable of blocking an illuminating optical path between a light source lamp and a light guide entrance end surface of an endoscope is driven by a step motor. The present invention relates to a diaphragm control device for a light source device.

[0002]

2. Description of the Related Art In order to automatically adjust the area of a light flux of illumination light incident on a light guide of an endoscope, a movable diaphragm provided between a light source lamp and a light guide entrance end face is driven by a step motor. It is known to have been made.

In such an aperture control device for a light source device for an endoscope, a brightness signal indicating the brightness of an endoscope observation screen is repeatedly detected in a short cycle by a control process by a microcomputer, and the brightness signal is detected. A drive pulse is applied to the step motor each time it is detected to drive the movable diaphragm to bring the brightness signal value close to a predetermined value.

In such an aperture control device for a light source device for an endoscope, the number of drive pulses given to the stepper motor is always the same for each detection of the luminance signal, and therefore changes by one control process. The rotation angle of the movable diaphragm is constant.

When the luminance signal value deviates from a predetermined value, the control processing of detection and driving is repeated several times so that the luminance signal value converges to a predetermined value and the brightness of the endoscopic observation screen becomes appropriate. The value is automatically adjusted.

[0006]

However, when the number of drive pulses given to the step motor in each control processing is constant, the moving speed of the movable diaphragm becomes slow when the number of pulses is set small. Then the response speed becomes slower, and conversely if you set a large number of pulses per time,
The luminance signal value may not converge to a predetermined value and the movable diaphragm may cause hunting.

Therefore, the number of drive pulses given to the step motor for each control processing is set to the most preferable value in consideration of various conditions, but the optimum value is set to the value of the endoscope to be used. It greatly differs depending on the type, and also greatly differs depending on the usage conditions at each time.

Therefore, conventionally, the response speed of the movable diaphragm is too slow or hunting occurs depending on the conditions, no matter how the number of drive pulses given to the step motor for each control process is set. There was an occasion.

Therefore, an object of the present invention is to provide a diaphragm control device for a light source device for an endoscope, which does not cause a response delay or hunting of a movable diaphragm driven by a step motor even if the use condition changes.

[0010]

In order to achieve the above object, an aperture control device for an endoscope light source device of the present invention provides an illumination optical path between a light source lamp and a light guide entrance end face of the endoscope. A diaphragm control device for a light source device for an endoscope in which a movable diaphragm capable of blocking an arbitrary amount is driven by a step motor, and the brightness of an observation screen of an endoscope is repeatedly detected in a short cycle, Each time, a drive pulse for bringing the brightness of the observation screen close to a predetermined value is given to the step motor, and a predetermined value setting means for setting the predetermined value is provided, and one observation Each time the screen brightness is detected, the number of drive pulses given to the step motor is changed according to the magnitude of the predetermined value, or is changed according to the rotation angle of the step motor, or Characterized in that so as to vary according to the type of serial endoscope.

[0011]

Embodiments will be described with reference to the drawings. FIG. 1 schematically shows the entire configuration of the endoscope 1 and the light source device / video processor 20. The tip of the insertion portion of the electronic endoscope 1 is, for example, charge-coupled to the imaging position of the object by the objective lens 2. A solid-state imaging device 3 including a device (CCD) is arranged and faces the exit end of an illumination light guide fiber bundle 4 for illuminating the observation range, and illuminates a subject with a wide distribution angle of illumination light. The illumination lens 5 is arranged.

In the connector portion 6 of the endoscope 1 which is detachably connected to the light source device / video processor 20, a signal line for transmitting a signal input / output to / from the solid-state image pickup device 3 is provided on the light source device / video processor 20 side. An electrical connector 7 for connecting to the light guide fiber bundle 4 and an incident end of the light guide fiber bundle 4 are arranged.

In the light source device / video processor 20,
In addition to a video signal processing unit 21 for processing a video signal sent from the solid-state image sensor 3, a light source lamp 22 for generating illumination light to be supplied to the light guide fiber bundle 4 and the like are provided. A TV monitor 49 is connected to the output end of the video signal processing unit 21, and an endoscopic observation image is displayed on the TV monitor 49.

A condenser lens 24 for converging the illumination light emitted from the light source lamp 22 to the incident end surface of the light guide fiber bundle 4 is arranged between the incident end of the light guide fiber bundle 4 and the light source lamp 22. Has been done.

A movable diaphragm is provided between the light source lamp 22 and the condenser lens 24 so that the illumination light path between them can be blocked by an arbitrary amount to change the area of the illumination light beam bundle entering the light guide fiber bundle 4. 25 is arranged, and the movable diaphragm 25 is driven by a step motor 26.

The reference numeral 23 is fixed so that three color filters of red (R), green (G) and blue (B) are sequentially inserted in the illumination optical path in order to perform illumination for so-called RGB sequential image pickup. It is an RGB rotary filter that is rotationally driven at a speed.

A lamp control circuit 27 for driving the light source lamp 22, a diaphragm drive circuit 28 for driving the movable diaphragm 25, a rotary filter drive circuit 29 for driving the RGB rotary filter 23, etc. are provided in the light source device / video processor 20. Controlled microcomputer 30
The operation is controlled by.

FIG. 2 shows the movable diaphragm 25. A thin plate is bent into a U-shaped cross section, and a rotary shaft 251 connected to the center of the bottom surface is arranged perpendicularly to the illumination optical axis. It is designed to be rotated.

FIG. 3 shows the movable diaphragm 25 viewed from the direction of the illumination optical axis. As shown in FIG. 3, when the plate surface of the movable diaphragm 25 is parallel to the illumination optical axis. The illumination optical path L is hardly blocked.

From this state, the illumination optical path L corresponds to the rotation angle of the movable diaphragm 25 driven by the step motor 26.
Are gradually blocked, and the illumination light flux incident on the light guide fiber bundle 4 is reduced.

FIG. 4 shows the diaphragm drive circuit 28, which includes a pulse control circuit unit 281 and a motor drive circuit unit 282. Among them, the pulse control circuit unit 281 has an instruction signal and a drive pulse signal for instructing either normal rotation for closing the movable diaphragm 25 or reverse rotation for opening from the microcomputer control unit 30 via an input / output port 41 described later. In response to this, the drive pulse applied to the step motor 26 is set. Then, the motor drive circuit unit 282 outputs a drive pulse for driving the step motor 26 in accordance with the pulse signal input from the pulse control circuit unit 281.

FIG. 5 shows the microcomputer control unit 30 and its surroundings. In the microcomputer control unit 30, programs and the like are stored on a system bus 32 connected to a central processing unit (CPU) 31 for performing arithmetic processing. Stored read-only memory (ROM) 33, random access memory (RA
M) 34 and a real time clock (RTC) 35 are connected.

A CR connected to the system bus 32
Through the T controller (CRTC) 37, the display character data stored in the video random access memory (video RAM) 36 and the video data output from the video signal processing unit 21 are combined and output to the TV monitor 49. It

The panel switch 201 of the light source device / video processor 20, the lamp control circuit 27 for controlling the light source lamp 22, and the external keyboard 202 are connected to the system bus 3 via the input / output ports 38, 39 and 40, respectively.
Connected to 2.

The panel switch 201 includes a movable diaphragm 25.
Select whether to automatically or manually adjust the brightness of the observation screen by operating
The brightness of the hand changeover switch or the observation screen is, for example, “1” to “10” in 10 steps of brightness index (predetermined brightness).
A brightness up switch and a down switch (brightness adjustment value setting means) for adjusting the brightness adjustment value) are arranged.

The signal output to the diaphragm drive circuit 28 is performed via the input / output port 41, and the brightness signal indicating the brightness of the observation screen taken out from the video signal processing unit 21 is, for example, 0 in the analog-digital converter 42. It is converted into a digital signal in the range of up to 255 and input to the microcomputer control unit 30.

Further, by connecting the connector section 6 of the endoscope 1 to the light source device / video processor 20, the memory 9 arranged in the endoscope 1 is connected to the microcomputer control section 30 via the input / output port 43. Connected to. In the memory 9,
The type of the endoscope 1 and other data unique to the endoscope are stored.

FIG. 6 shows the observation screen adjusted by the switch of the panel switch 201 from 1 to 10 of 1.
The reference value stored in the ROM 33 is shown so as to correspond to the 0-level brightness index, and the brightness index of 1 to 10 is thus converted into the reference value of 16 to 161 in the microcomputer control unit 30. .

By the way, the luminance signal value y of the electronic endoscope 1
Varies depending on the type of endoscope even when the same subject is observed from the same distance. This is because the F number of the objective lens 2 and the number of the light guide fiber bundles 4 differ depending on the model of the endoscope.

FIG. 7 shows three types of endoscopes A,
The relationship between the rotation angle of the step motor 26 and the luminance signal value in the cases of B and C is shown, where A is the case of an endoscope for the large intestine and C is the case of an endoscope for the bronchus.

FIG. 8 shows the ROM 33 of the microcomputer controller 30.
Shows the contents of the main program stored in
Indicates a processing step. Here, after performing a predetermined initial setting (S1), a process set by the panel switch 201 (S2), an input process from the keyboard 202 (S3), a process related to the lamp control circuit 27 (S4), an internal view. The process (S5) related to the mirror 1 side, the process of displaying the date and time (S6), and the other process (S7) are repeated in order.

FIG. 9 shows the operation control of the step motor 26 for driving the movable diaphragm 25 in order to automatically adjust the brightness of the endoscopic observation screen to a value corresponding to the set brightness index. It is a control flow chart, for example, 0.01
It is controlled by interrupt processing that is executed periodically at intervals of once a second.

Here, a luminance signal is first input from the video signal processing unit 21 (S11), and the difference between the luminance signal value and the reference value based on the brightness index is obtained (S12). Then, when the luminance signal value is larger than the reference value, a normal rotation signal is sent to the step motor 26 (S13, S14), and when the luminance signal value is less than or equal to the reference value, a reverse rotation signal is sent to the step motor 26 ( S15).

Then, in the next step S16, the number of drive pulses applied to the step motor 26 each time the brightness of the observation screen is detected is changed according to the magnitude of the brightness index (reference value). Drive pulse is applied to the step motor 26. However, if the difference value of | reference value-luminance signal value | is within the allowable limit width, the step motor 26 is not driven.

Here, the allowable limit width of the luminance signal value at which the driving of the movable diaphragm 25 by the step motor 26 starts is set to B, and when the driving pulse of 1 pulse is given to the step motor 26 (hence the movable diaphragm 25).
Assuming that the angular displacement is 0.5 °, looking at the characteristic curve A of FIG. 7, the change Δy of the luminance signal value when one pulse is given to the step motor 26 changes as shown in FIG. . Further, as shown in FIG. 11, the condition that the luminance signal value converges within the allowable limit width B and hunting does not occur is Δy ≦ 2B.

Therefore, the allowable limit width B is set to B = 3, the number of drive pulses applied to the step motor 26 in one control process is set to P (P1, P2 ...), and the brightness index is 10.
P1 = 3 when, and P2 = 2 when the brightness index is 7-9,
When the brightness index is 1 to 6, if P3 = 1, a fast response speed can be obtained in a range where the movable diaphragm 25 does not cause hunting.

FIG. 12 shows S1 for performing the control processing.
6 shows the processing content of No. 6, and if the difference value of | reference value-luminance signal value | is smaller than the permissible limit width B, the interrupt processing is ended as it is (S21).

When the brightness index is 10, P1 =
Three driving pulses are given to the step motor 26 to end the interrupt processing (S22, S23), and the brightness index is 9 to.
In case of 7, P2 = 2 drive pulses are applied to the step motor 2
6 to end the interrupt processing (S24, S25),
When the brightness index is 6 to 1, P3 = 1 driving pulse is given to the step motor 26 to end the interrupt process (S26, S27).

If the brightness index information is abnormal and the brightness index is other than 1 to 10, the brightness index is forcibly reset to, for example, an intermediate value of 5, and then the interrupt processing is terminated. (S28).

Next, a second embodiment of the present invention will be described. The difference from the first embodiment described above is only the content of the control processing in S16, so only the control processing portion will be described. .

With respect to the characteristic curve A of FIG. 7, when the step motor 26 rotates 0.5 ° by one drive pulse, the difference Δy of the luminance signal values changes as shown in FIG. Therefore, in this embodiment, the number of drive pulses applied to the step motor 26 is changed by one control process according to the rotation angle of the step motor 26 (and thus the rotation angle of the movable diaphragm 25).

Specifically, the driving pulse number P is P4 =
1, P5 = 2, P6 = 3, and when the rotation angle θ of the movable diaphragm 25 is 23 ° (θ1) or more, the number of drive pulses P
4 is selected, and the rotation angle θ is 16 ° (θ2) to 23 °
When (θ1), P5 is selected and the rotation angle θ is 16 °
When it is less than (θ2), if P6 is selected, a fast response speed can be obtained in a range where hunting does not occur.

FIG. 14 shows S1 for performing the control processing.
6 shows the processing content of No. 6, and if the difference value of | reference value-luminance signal value | is smaller than the permissible limit width B, the interrupt processing is ended as it is (S31).

The rotation angle θ of the movable diaphragm 25 is θ1.
If (23 °) or more, P4 = 1 driving pulse is given to the step motor 26 to end the interrupt process (S3).
2, S33), the rotation angle θ is θ2 (16 °) to θ1
In the case of (23 °), P5 = 2 drive pulses are given to the step motor 26 to end the interrupt processing (S34,
S35), when the rotation angle θ is less than θ2 (16 °), P
6 = 3 drive pulses are given to the step motor 26 to end the interrupt processing (S36, S37).

Step S38 is a precautionary process for resetting the diaphragm angle θ when there is an abnormality in the angle information of the movable diaphragm 25 or the actual angle of the movable diaphragm 25, and is the first embodiment. This corresponds to the processing of S28.

Next, the third embodiment of the present invention will be described. The difference from the above-mentioned second embodiment is also S1.
Since only the contents of the control processing of No. 6 are described, only the control processing portion will be described.

Characteristic curves A, B and C in FIG. 7 show the case of three different models under the condition that the luminance signal value is maximum. For example, A is for the large intestine, B is the upper part such as esophagus and stomach. For the digestive tract, C is for a small-diameter endoscope such as for the bronchus and ENT.

When the step motor 26 rotates 0.5 ° by one drive pulse, the difference Δy between the brightness signal values of A, B, and C models changes as shown in FIG. Therefore, in this embodiment, the number of drive pulses applied to the step motor 26 by one control process is changed for each model according to the rotation angle of the step motor 26 (and thus the rotation angle of the movable diaphragm 25).

Specifically, the drive pulse number P is set to P7 = 1 and P8 = 2 for the model A, and P9 = for the model B.
2, P10 = 3, and for model C, P11 = 4. Setting angle θ3 for model A is 23 °, model B
The setting angle θ4 for is 20 °.

FIG. 16 shows S1 for performing the control processing.
6 shows the processing content of No. 6, and if the difference value of | reference value-luminance signal value | is smaller than the permissible limit width B, the interrupt processing is terminated as it is (S41).

In the case of the model A (S42), when the rotation angle θ of the movable diaphragm 25 is larger than θ3 (23 °), P7 = 1 driving pulse is given to the step motor 26 and the interruption process is finished. Then, the rotation angle θ of the movable diaphragm 25
Is less than .theta.3 (23.degree.), P8 = 2 drive pulses are given to the step motor 26 to end the interrupt process (S43 to S45).

Next, in the case of model B (S46), when the rotation angle θ of the movable diaphragm 25 is larger than θ4 (20 °), P9 = 2 drive pulses are given to the step motor 26 and interrupt processing is performed. And the rotation angle θ of the movable diaphragm 25
Is less than .theta.4 (20.degree.), P10 = 3 drive pulses are given to the step motor 26 to end the interrupt process (S47 to S49).

Finally, in the case of the model C, regardless of the rotation angle of the movable diaphragm 25, P11 = 4 drive pulses are given to the step motor 26 to end the interrupt processing (S50).

[0054]

According to the present invention, the number of drive pulses applied to the step motor for driving the aperture is changed in accordance with the predetermined brightness adjustment value which is variably set, each time the brightness of the observation screen is detected. Or the number of drive pulses is changed according to the rotation angle of the step motor, or the number of drive pulses is changed according to the type of endoscope. The speed can be as fast as possible.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of an embodiment.

FIG. 2 is a perspective view of a movable diaphragm according to an embodiment.

FIG. 3 is a front view of a movable diaphragm of the embodiment.

FIG. 4 is a block diagram of a diaphragm driving circuit according to an embodiment.

FIG. 5 is a block diagram of a control circuit according to an embodiment.

FIG. 6 is a table showing corresponding values when the brightness index of the embodiment is converted into a reference value.

FIG. 7 is a characteristic diagram showing the relationship between the step motor rotation angle and the luminance signal value according to the model of the endoscope in the embodiment.

FIG. 8 is a flowchart showing the contents of a main program of the embodiment.

FIG. 9 is a flowchart showing the contents of interrupt processing for drive pulse control according to the embodiment.

FIG. 10 is a chart showing characteristics of the first embodiment.

FIG. 11 is a diagram showing characteristics of the first embodiment.

FIG. 12 is an S1 for controlling a drive pulse according to the first embodiment.
It is a flowchart which shows the content of 6.

FIG. 13 is a chart showing characteristics of the second embodiment.

FIG. 14 is an S1 for controlling a drive pulse according to the second embodiment.
It is a flowchart which shows the content of 6.

FIG. 15 is a chart showing characteristics of the third embodiment.

FIG. 16 is an S1 for controlling a drive pulse according to the third embodiment.
It is a flowchart which shows the content of 6.

[Explanation of symbols]

1 endoscope 25 movable diaphragm 26 step motor 30 Microcomputer control unit 201 panel switch

Continuation of front page (56) Reference JP-A-1-31115 (JP, A) JP-A-5-150154 (JP, A) JP-A-51-93217 (JP, A) JP-A-2-89033 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 23/26 A61B 1/04 362

Claims (2)

(57) [Claims] 1. A diaphragm control device for a light source device for an endoscope, wherein a step motor drives a movable diaphragm capable of blocking an illumination optical path between a light source lamp and an end face of a light guide of an endoscope by an arbitrary amount. That is, the brightness of the observation screen of the endoscope is repeatedly detected in a short cycle, and each time, a drive pulse for bringing the brightness of the observation screen close to a predetermined brightness adjustment value is applied to the step motor. In the one that is given, with the brightness adjustment value setting means for setting the predetermined brightness adjustment value, the number of drive pulses given to the step motor for each brightness detection of the observation screen is given, An aperture control device for a light source device for an endoscope, wherein the aperture control device is changed according to the magnitude of the predetermined brightness adjustment value. 2. A diaphragm control device for a light source device for an endoscope, wherein a step motor drives a movable diaphragm capable of blocking an illumination light path by an arbitrary amount between a light source lamp and a light guide entrance end face of the endoscope. That is, the brightness of the observation screen of the endoscope is repeatedly detected in a short cycle, and each time, a drive pulse for bringing the brightness of the observation screen close to a predetermined brightness adjustment value is applied to the step motor. The endoscope which is characterized in that the number of drive pulses given to the step motor is changed each time the brightness of the observation screen is detected, according to the rotation angle of the step motor. Control device for a light source device for automobiles.