JP3431294B2 - 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. Generally, the brightness signal value differs from the predetermined value by more than the allowable limit. In this case, the movable diaphragm is driven.

[0004]

However, when the width of the permissible limit of the luminance signal value at which the movable diaphragm drive by the step motor starts is constant, the permissible limit width becomes too narrow depending on the situation, and the luminance signal value becomes too narrow. May not converge within the allowable limit width and the movable aperture may cause hunting.

In some cases, on the contrary, the permissible limit width is too wide, so that the brightness of the endoscopic observation screen is not in a proper state and is too bright or too dark to obstruct the observation. There is.

Therefore, the present invention is for an endoscope which does not cause hunting of a movable diaphragm driven by a step motor even when the use condition changes and which can automatically adjust the endoscope screen to an appropriate brightness. An object is to provide a diaphragm control device for a light source device.

[0007]

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, when the brightness of the observation screen is different from the predetermined value by more than the allowable limit, a drive pulse for bringing the brightness of the observation screen close to the predetermined value is given to the step motor. In addition, a predetermined value setting means for setting the predetermined value is provided, and the allowable limit width of the brightness of the observation screen for the set predetermined value is changed according to the size of the predetermined value. Or the width of the permissible limit is changed according to the rotation angle of the step motor, or the width of the permissible limit is changed according to the type of the endoscope. It is characterized in that it is changed according to.

[0008]

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 is arranged between the incident end of the light guide fiber bundle 4 and the light source lamp 22 to converge the illumination light emitted from the light source lamp 22 onto the incident end face of the light guide fiber bundle 4. Has been done.

A movable diaphragm is arranged between the light source lamp 22 and the condenser lens 24 so that the illumination light path between the light source lamp 22 and the condenser lens 24 can be blocked by an arbitrary amount to change the area of the illumination light beam bundle incident on 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 a fixed value 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 a state in which the movable diaphragm 25 is viewed from the illumination optical axis direction. 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, a program and the like are stored in 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
Brightness of the hand changeover switch or the observation screen, for example, 10 steps of brightness index (brightness adjustment) from "1" to "10"
Brightness up switch and down switch, etc. are arranged for adjustment by adjusting value .

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.

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 an 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 endoscopes A, 3 of different types.
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 is a diagram for controlling the operation of the step motor 26 that drives the movable diaphragm 25 in order to automatically adjust the brightness of the endoscopic observation screen to one that always corresponds 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). And
When the brightness signal value is larger than the reference value, a normal rotation signal is sent to the step motor 26 (S13, S14), and when the brightness signal value is less than the reference value, a reverse rotation signal is sent to the step motor 26 (S15). .

Then, in the next S16, the allowable limit width of the difference value of | reference value-luminance signal value | is selected from a plurality of types in accordance with the set brightness index, and the difference value is allowed. If the limit width is exceeded, the step motor 26 is given a predetermined number of drive pulses. If the difference value is within the allowable limit width, the step motor 26 is not driven.

Here, assuming that the number of drive pulses applied to the step motor 26 is 2 pulses uniformly, and the angular displacement of the step motor 26 (and therefore the movable diaphragm 25) at that time is 1 °, the characteristic curve A of FIG. As seen, the change Δ in the luminance signal value when the step motor 26 rotates 1 °
y changes as shown in FIG. 10. Therefore, as shown in FIG. 11, the allowable limit width is B, the step motor 26 is
Assuming that the difference between the luminance signal values when 1 is rotated by 1 ° is Δy, the condition that the luminance signal values converge within the allowable limit width B and hunting does not occur is Δy ≦ 2B.

Therefore, the allowable limit width B is B1 = 2, B2
= 3, B3 = 4, the allowable limit width B1 is selected when the brightness index is 10, the B2 is selected when the brightness index is 9 to 7, and the brightness index is 6 to 1 Choose B3,
A high response speed can be obtained in the range where hunting does not occur.

FIG. 12 shows S1 for performing the control processing.
6 shows the processing contents of 6, and when the brightness index is 10,
The difference value of | reference value-luminance signal value | is the allowable limit width B1 (2)
If it is larger, two predetermined pulses are given to the step motor 26, and when the difference value is B1 (2) or less, the interrupt process is terminated as it is (S21 to S23).

When the brightness index is 9 to 7, if the difference value is larger than the allowable limit width B2 (3), two predetermined pulses are given to the step motor 26, and when the difference value is B2 (3) or less. Ends the interrupt processing as it is (S24 to S2
6).

When the brightness index is 6 to 1, if the difference value is larger than the allowable limit width B3 (4), two predetermined pulses are given to the step motor 26, and when the difference value is B3 (4) or less, it is kept as it is. The interrupt processing ends (S27 to S29).

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. (S30).

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 1 ° by one driving, the difference Δy of the luminance signal values changes as shown in FIG. Therefore, in this embodiment, the permissible limit width B of the difference value of | reference value-luminance signal value | is changed according to the rotation angle of the step motor 26 (hence the rotation angle of the movable diaphragm 25).

Specifically, the allowable limit width B is B4 = 4,
When B5 = 3 and B6 = 2 are set and the rotation angle θ of the movable diaphragm 25 is 23 ° (θ1) or more, the allowable limit width B4 is selected, and the rotation angle θ is from 16 ° (θ2) to 23 ° ( θ1)
In this case, B5 is selected, and when the rotation angle θ is less than 16 ° (θ2), B6 is selected, so that 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 contents of No. 6, and the rotation angle θ of the movable diaphragm 25.
Is θ1 (23 °) or more, if the difference value of | reference value-luminance signal value | is larger than the allowable limit width B4 (4), predetermined two pulses are given to the step motor 26, and the difference value is B4.
(4) In the following cases, interrupt processing is terminated as it is (S
31-S33).

When the rotation angle θ is from θ2 (16 °) to θ1 (23 °), the difference value is the allowable limit width B5 (3).
If it is larger, two predetermined pulses are given to the step motor 26, and when the difference value is B5 (3) or less, the interrupt process is terminated as it is (S34 to S36).

When the rotation angle θ is less than θ2 (16 °),
If the difference value is larger than the permissible limit width B6 (2), two predetermined pulses are given to the step motor 26, and if the difference value is B6 (2) or less, the interrupt processing is terminated as it is (S37 to S37).
39).

S40 is a precautionary process for resetting the aperture angle θ when the angle information of the movable aperture 25 or the actual angle is abnormal, and is S30 of the first embodiment.
Corresponds to the processing of.

Next, a third embodiment of the present invention will be described. The difference from the above-mentioned second embodiment is 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 cases 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 1 degree by one driving, the difference Δy between the brightness signal values of the respective models A, B and C changes as shown in FIG. Therefore, in this embodiment, the permissible limit width B of the difference value of | reference value-luminance signal value | is changed for each model according to the rotation angle of the step motor 26 (thus, the rotation angle of the movable diaphragm 25). .

Specifically, the allowable limit width B is set to B7 = 4 and B8 = 3 for the model A, and B9 = for the model B.
3, B10 = 2, and for model C, B11 = 2. 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 contents of No. 6, and in the case of model A (S4
1) When the rotation angle θ of the movable diaphragm 25 is larger than θ3 (23 °), if the difference value of | reference value-luminance signal value | is larger than the allowable limit width B7 (4), a predetermined two pulses are used for the step motor. 26, and when the difference value is B7 (4) or less, the interrupt process is ended as it is (S42 to S43).

The rotation angle θ of the movable diaphragm 25 is θ3.
When it is less than (23 °), the difference value is the allowable limit width B8 (3).
If it is larger, two predetermined pulses are given to the step motor 26, and when the difference value is B8 (3) or less, the interrupt process is terminated as it is (S45, S46).

Next, in the case of model B (S47), when the rotation angle θ of the movable diaphragm 25 is larger than θ4 (20 °), the difference value of | reference value-luminance signal value | is the allowable limit width B9.
If it is larger than (3), two predetermined pulses are given to the step motor 26, and if the difference value is B9 (3) or less, the interrupt process is terminated as it is (S48 to S50).

The rotation angle θ of the movable diaphragm 25 is θ4.
When it is (20 °) or less, the difference value is the allowable limit width B10.
If it is larger than (2), two predetermined pulses are given to the step motor 26, and when the difference value is B10 (2) or less, the interrupt process is ended as it is (S51, S52).

Finally, in the case of model C (S5
3), irrespective of the rotation angle of the movable diaphragm 25, | reference value-
If the difference value of the luminance signal value | is larger than the allowable limit width B11 (2), two predetermined pulses are given to the step motor 26, and when the difference value is B11 (2) or less, the interrupt process is terminated as it is (S53, S54). ).

[0054]

According to the present invention, the permissible limit width of the brightness at which the step motor for driving the diaphragm is driven is variably set to the predetermined brightness when the brightness of the observation screen is detected once. Since the allowable limit width is changed according to the rotation angle of the step motor, or the allowable limit width is changed according to the type of the endoscope,
The response speed can be made as fast as possible by preventing the movable diaphragm from hunting.

[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-1- 262515 (JP, A) (58) Fields surveyed (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. However, if the brightness of the observation screen of the endoscope is repeatedly detected in a short cycle, and each time the brightness of the observation screen is different from the brightness adjustment value by more than the allowable limit, A drive pulse for bringing the brightness of the observation screen close to the brightness adjustment value is given to the step motor, and the width of the allowable limit is changed according to the rotation angle of the step motor. A diaphragm control device for a light source device for an endoscope, characterized in that 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. However, if the brightness of the observation screen of the endoscope is repeatedly detected in a short cycle, and each time the brightness of the observation screen is different from the brightness adjustment value by more than the allowable limit, In the one in which a drive pulse for making the brightness of the observation screen close to the brightness adjustment value is given to the step motor, the width of the allowable limit is changed according to the type of the endoscope. A diaphragm control device for a light source device for an endoscope, characterized in that