JP3431293B2 - 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 at a constant short time interval by a control process by a microcomputer, Each time the brightness signal is detected, a fixed number of drive pulses are applied to the step motor to drive the movable diaphragm, thereby bringing the brightness signal value close to a predetermined value.

Therefore, when the brightness signal value is deviated from the predetermined value, the brightness signal value is converged to the predetermined value by repeating the control process of the detection and the driving several times, and the brightness of the endoscopic observation screen is reduced. It is automatically adjusted to an appropriate value.

[0005]

As described above, since the number of drive pulses given to the step motor for each control process is constant, the change of the light shielding amount caused by the rotation of the step motor by one drive pulse is changed. If the change in the brightness of the endoscope observation screen is large, the movable diaphragm may cause hunting.

Therefore, in order to prevent hunting, 1
If the change in the amount of light shielding caused by the rotation of the step motor due to the individual drive pulses is reduced, the moving speed of the movable diaphragm becomes slow and the response speed becomes slow.

Therefore, an object of the present invention is to provide a diaphragm control device for an endoscope light source device in which hunting of a movable diaphragm driven by a step motor does not occur and a response delay does not occur.

[0008]

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 that can be blocked by an arbitrary amount is driven by a step motor, and a drive pulse for bringing the brightness of an observation screen of an endoscope close to a predetermined value. In a case where the control process applied to the step motor is repeatedly performed at regular time intervals, an excitation method switching means for switching the excitation method of the step motor in accordance with the diaphragm state of the movable diaphragm is provided, or An excitation system switching means for switching the excitation system of the step motor in accordance with the brightness of the observation screen is provided, or The excitation scheme over data, characterized in that a excitation method switching means for switching in response to the type of the endoscope.

[0009]

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 section 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 arranged 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 bundle of illumination light rays 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 fixed so that filters for three colors 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 a 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 of the movable diaphragm 25 is arranged perpendicularly to the illumination optical axis. It is designed to be rotated.

FIG. 3 shows the movable diaphragm 25 seen 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 outputs a switching instruction signal for switching the excitation method between two-phase excitation and 1-2-phase excitation from the microcomputer control unit 30 via an input / output port 41 described later, and for closing the movable diaphragm 25. A drive pulse to be given to the step motor 26 is set by receiving an instruction signal instructing either normal rotation or reverse rotation for opening and a drive pulse signal. 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 peripherals. In the microcomputer control unit 30, programs 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
A hand changeover switch, a brightness up switch and a down switch for adjusting the brightness of the observation screen with a brightness index of 10 steps from "1" to "10" 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 extracted 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.

The DIP switch 11 connected to the input / output port 43 is provided so that the input end of the input / output port 43 can be switched to a high level or a low level by manually turning it on / off. ing.

FIG. 6 shows the observation screen adjusted from 1 to 10 by the switch of the panel switch 201.
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. .

FIG. 7 shows the relationship between the rotation angle θ of the step motor 26 and the luminance signal value (A / D output value) of the observation image of the endoscope when the U-shaped movable diaphragm 25 is used. There is.
Here, when comparing the luminance signal value and the reference value, the permissible range is ± B (that is, if the luminance signal value is the reference value ± B, it is considered to match the reference value), The rotation angle of the step motor 26 is Δθ, and the inclination of the tangent line at each point of the curve y = f (θ) in FIG. 7 is dy / dθ.
Assuming that there is no delay in the drive system of No. 6, from FIG. 8, if (dy / dθ) Δθ ≦ 2B ∴dy / dθ ≦ 2B / Δθ (a), the movable diaphragm 25 does not cause hunting. Become.

As shown in FIG. 7, when the curve of y = f (θ) is a curve that is monotonically decreasing and convex upward, the value of dy / dθ increases as θ increases, and There is a possibility that the formula (a) will not be satisfied.

Then, at that time, the excitation method of the step motor 26 is switched from the two-phase excitation to the one-two phase excitation in which the rotation angle per pulse is halved, and the value of Δθ is halved, whereby 2B / Δθ. Double the value of (a)
Try to satisfy the formula.

Specifically, the number of pulses given to the motor at one time is set to 1 (P = 1), and at that time, Δθ = 0.
It is assumed to be 5 [deg]. If B = 1, then (a)
The value on the right side of the equation is 2B / Δθ = 4.

From the curve of y = f (θ) in FIG. 7, dy / dθ
Is calculated to be approximately dy / d in the range of θ> 15 [deg]
θ> 4. In addition, dy / dθ <
It is 8. That is, the expression (a) is not satisfied in this range.

Therefore, in the range of θ> 15 [deg], the excitation method of the step motor 26 is set to 1-2 phase excitation, and Δθ =
If it is set to 0.25 [deg], 2B / Δθ = 8, and θ
The expression (a) is satisfied even in the range of> 15 [deg].

FIG. 9 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 related to the mirror 1 side (S5), the process of displaying date and time etc. (S6) and the other process (S7) are carried forward in order.

FIGS. 10 and 11 show 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. FIG. 6 is a control flow chart for performing the control, which is controlled by, for example, interrupt processing that is periodically performed at intervals of 0.03 seconds.

Here, a counter for counting the number of drive pulses given to the step motor 26 is c, and the step motor 26 is
P is the number of pulses given in one control process, and u2 is a variable representing the excitation method of the step motor 26, and u2 = 0 is 2
Phase excitation, u2 = 1 indicates 1-2 phase excitation.

The relationship between the rotation angle θ of the step motor 26, the counter c that counts the number of drive pulses, and the amount of light incident on the light guide fiber bundle 4 is as shown in FIG. Further, the value of c when dy / dθ = 2B / Δθ holds is set to N.

In this control, since the value of the counter c corresponds to the rotation angle of the step motor 26, it is first determined whether c is larger than N (S11), and then the excitation method is determined (S12, S15).

When c is larger than N, the equation (a) is not satisfied in the two-phase excitation, so that in the two-phase excitation (u2 =
In 0), u2 = 1 is set and the excitation method is changed to 1-2 phase excitation (S12 to S14). c is larger than N and originally 1-2
The excitation method is not changed during phase excitation.

When c is not larger than N, the expression (a) is satisfied by the two-phase excitation.
(1) sets u2 = 0 and changes the excitation method to two-phase excitation (S15 to S17). When c is not larger than N and originally two-phase excitation is used, the excitation method is not changed.

When the excitation method is determined in this way, a luminance signal is input from the video signal processing section 21 (S18),
The brightness signal value is compared with a reference value based on the brightness index (S19). Then, if the difference is within the allowable range and the brightness of the observation screen matches the brightness index,
The interrupt process is terminated as it is (S20).

When the difference between the brightness signal value and the reference value is larger than the allowable value, it is judged whether the brightness signal value is larger or smaller than the reference value (S21). A normal rotation signal is sent to the diaphragm drive circuit 28 to drive the movable diaphragm 25 in the closing direction (S22), and the counter c
2P is added to the number of counts of 2 phase excitation, and 1-
In the case of two-phase excitation, P is added (S23).

When the luminance signal is smaller than the reference value, the diaphragm drive circuit 2 drives the movable diaphragm 25 in the opening direction.
A reverse rotation signal is sent to 8 (S24), and 2P is subtracted from the count number of the counter c in the case of two-phase excitation, and P is subtracted from the number of 1-2 phase excitation (S25).

Finally, a predetermined plurality of drive pulses (for example, the number of pulses P = 3) are given to the diaphragm drive circuit 28 (S26), and the interrupt processing is finished. By doing so, when the movable diaphragm 25 is gradually closed, the excitation method of the step motor 26 is switched from the two-phase excitation to the one-two-phase excitation on the way, so that automatic dimming can be performed without causing hunting. It can be carried out.

However, if the movable diaphragm 25 has an I-shaped cross section as shown in FIGS. 13 and 14,
As shown in FIG. 15, the curve of y = g (θ) has a monotonically decreasing shape and has a substantially convex shape. As θ decreases, dy /
The value of dθ becomes large.

Therefore, when the movable diaphragm 25 having such an I-shaped cross section is used, in the control steps of S11 to S17, contrary to the case of the U-shaped cross section, when θ is smaller than a certain value, 1-2 Phase excitation is performed, and when θ is larger than that, two-phase excitation is performed.

FIG. 16 is a control processing flow chart of the second embodiment, which is basically the same as that of the first embodiment. The movable diaphragm 25 is shown to have a U-shaped cross section.

When the luminance signal value is smaller than the minimum reference value (REFmin = 16 in FIG. 7) to some extent, only the operation of opening the movable diaphragm 25 is performed, and the movable diaphragm 25 is not stopped there. . Therefore, since hunting does not occur, the step motor 26 can be driven by two-phase excitation having a fast reaction regardless of the value of the counter c.

Therefore, in this control process, the luminance signal is first input (S31), the value of the counter c is compared with N (S32), and when c is not larger than N, the same as in the first embodiment. Phase excitation is used (S37 to S39).

However, when c is larger than N, the luminance signal value is compared with a constant M smaller than the minimum reference value (S33), and when the luminance signal value is larger than M, the first embodiment is used. Similarly, 1-2 phase excitation is performed (S3
4 to S36), if the luminance signal value is M or less, S33
To S37, the two-phase excitation is performed.

When the excitation method is determined, the magnitude of the luminance signal value and the reference value are compared in S40, and the control process thereafter is shown in FIG.
Second half S20 of the control process of the first embodiment shown in FIG.
It is the same as S26.

Also in this embodiment, when the movable diaphragm 25 having an I-shaped cross section is used, contrary to the case of the U-shaped cross section, 1-2 phase excitation is performed when θ is smaller than a certain value. θ
Is larger than that, two-phase excitation is performed, and when the luminance signal value is larger than the maximum reference value (REFmax = 161 in FIG. 15), all two-phase excitation is performed.

FIG. 17 is a diagram for explaining the third embodiment. Even if the luminance signal value y of the observation image of the endoscope is the same as that of the same subject observed from the same distance, It depends on the type A, B, and C of the endoscope. This is the objective lens 2
This is because the F number and the number of light guide fiber bundles 4 vary depending on the model of the endoscope. In FIG. 17, A is an endoscope for the large intestine, and C is an endoscope for the bronchus.

In the case of such an example, in the case of the bronchoscope C, the value of dy / dθ is small regardless of the angle of the step motor 26, so that the step motor 26 is always driven by two-phase excitation. Hunting does not occur.

Therefore, in the third embodiment, the type of the endoscope is read from the memory 9 in the endoscope 1 into the microcomputer control unit 30, and in the case of the endoscope C, only the two-phase excitation is performed. The motor 26 is driven, and in the case of the endoscope A or B, two-phase excitation and 1-
Two-phase excitation is switched to drive.

[0056]

According to the present invention, the excitation method of the step motor for driving the movable diaphragm is switched according to the diaphragm state of the movable diaphragm, the brightness of the observation screen, or the type of endoscope. Thus, the response speed can be made as fast as possible within the range in which the movable diaphragm does not cause hunting, depending on the usage state.

[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 having a U-shaped cross section.

FIG. 3 is a front view of a movable diaphragm having a U-shaped cross section.

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 chart showing a correspondence relationship between a brightness index and a reference value according to the embodiment.

FIG. 7 is a characteristic diagram of an example showing a relationship between a rotation angle of a step motor and a luminance signal value when a movable diaphragm having a U-shaped cross section is used.

FIG. 8 is a characteristic diagram of an example showing a relationship between a rotation angle of a step motor and a luminance signal value when a movable diaphragm having a U-shaped cross section is used.

FIG. 9 is a control processing flowchart of the first embodiment.

FIG. 10 is a control processing flowchart of the first embodiment.

FIG. 11 is a control processing flowchart of the first embodiment.

FIG. 12 is a table showing the relationship among the rotation angle θ of the step motor, the counter value c, and the amount of light incident on the light guide fiber bundle of the first embodiment.

FIG. 13 is a perspective view of a movable aperture stop having an I-shaped cross section.

FIG. 14 is a front view of a movable aperture stop having an I-shaped cross section.

FIG. 15 is a characteristic diagram of an example showing a relationship between a rotation angle of a step motor and a luminance signal value when a movable diaphragm having an I-shaped cross section is used.

FIG. 16 is a control processing flowchart of the second embodiment.

FIG. 17 is a characteristic diagram showing the relationship between the step motor rotation angle and the brightness signal value for each type of endoscope for explaining the third embodiment.

[Explanation of symbols]

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

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-1-31115 (JP, A) JP-A-3-11407 (JP, A) JP-A-2-89033 (JP, A) JP-A-64- 48014 (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. In the case where the control process of giving a drive pulse for making the brightness of the observation screen of the endoscope close to a predetermined value to the step motor is repeatedly performed at a constant time interval, by being driven by the step motor, Above movable diaphragm
2 step excitation of the above step motor in the displacement region
However, hunting does not occur in the operation of the movable diaphragm.
The hunting area is set in advance, and the excitation method switching means for switching the excitation method of the step motor in accordance with the diaphragm state of the movable diaphragm is provided ,
Set the motor excitation method to 2 phases within the above hunting-free area.
Excitation, switch to 1-2 phase excitation outside the above hunting-free area
A diaphragm control device for a light source device for an endoscope, characterized in that it is replaced . 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. In the one in which a control pulse for giving a drive pulse for bringing the brightness of the observation screen of the endoscope close to a predetermined value is repeatedly performed at a constant time interval, the movable diaphragm is driven by the step motor. Being weird
In the variable area of the brightness of the observation screen
Even if the step motor is two-phase excitation,
Pre-set a non-hunting area where hunting does not occur
In addition, an excitation method switching means for switching the excitation method of the step motor according to the brightness of the observation screen is provided to change the excitation method of the step motor to the
2-phase excitation in the hunting area, outside the hunting area
Then, the aperture control device of the light source device for an endoscope is characterized in that it is switched to 1-2 phase excitation .