JP3517283B2 - Aperture control device of light source device for endoscope - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a movable stop capable of blocking an illumination optical path by an arbitrary amount between a light source lamp and a light guide entrance end face of an endoscope. The present invention relates to an aperture control device of an endoscope light source device driven by a motor. 2. Description of the Related Art In order to automatically adjust the area of a light beam of illumination light to be incident on a light guide of an endoscope, a movable stop provided between a light source lamp and a light guide entrance end face is controlled by a step motor. There is known one that is driven. In such an aperture control device for an endoscope light source device, a brightness signal indicating the brightness of an endoscope observation screen is repeatedly detected at fixed short time intervals by control processing by a microcomputer. Each time a luminance signal is detected, a fixed number of drive pulses are given to a stepping motor to drive the movable aperture so that the luminance signal value approaches a predetermined value. Therefore, when the luminance signal value deviates from the predetermined value, the luminance signal value converges to the predetermined value by repeating the detection and drive control processing several times, and the brightness of the endoscope observation screen is reduced. It is automatically adjusted to an appropriate value. [0005] The above-described control processing is performed at a fixed short time interval. However, if the time interval is set long, the moving speed of the movable diaphragm becomes slow and the response speed becomes slow. On the contrary, if the time interval of the control processing is set to be short, the movable diaphragm may cause hunting. Accordingly, the time interval of the control process is set to the most preferable interval in consideration of various conditions. However, the optimal time interval greatly varies depending on the type of endoscope used, and the time interval used at each time is different. It differs greatly depending on the conditions. Therefore, conventionally, no matter how the time interval of the control processing of the step motor for driving the movable aperture is set, the response speed is too slow or hunting occurs depending on the condition. Further, when there is a change in the mechanism of the movable diaphragm, software or hardware must be changed in order to change the control processing time interval to a new optimum value. SUMMARY OF THE INVENTION It is an object of the present invention to provide a diaphragm control device for an endoscope light source device which does not cause a response delay or hunting of a movable diaphragm driven by a step motor even when various conditions change. In order to achieve the above object, an aperture control device of an endoscope light source device according to the present invention comprises a light source lamp and a light guide entrance end face of the endoscope. An aperture control device of an endoscope light source device that drives a movable aperture capable of blocking an illumination optical path by an arbitrary amount by a step motor, for controlling the brightness of an observation screen of the endoscope to a predetermined value. In a control system in which a plurality of drive pulses are repeatedly applied to the step motor at a constant time interval, the time interval of the control process can be selected from a plurality of time intervals. The time interval of the control process may be automatically selected according to the type of endoscope used, or the time interval of the control process may be selected by a manual switch. You may make it so. 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 distal end of the insertion portion of the electronic endoscope 1 is connected to the image forming position of the object by the objective lens 2 by, for example, charge coupling. A solid-state image pickup device 3 composed of a device (CCD) is disposed, and the light distribution angle of the illuminating light is widened to irradiate a subject facing the exit end of an illumination light guide fiber bundle 4 for illuminating the observation range. Illumination lens 5 is arranged. The connector section 6 of the endoscope 1 which is detachably connected to the light source device / video processor 20 includes a signal line for transmitting signals input / output to / from the solid-state image pickup device 3 to 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. The light source device and video processor 20 includes:
In addition to a video signal processing unit 21 for processing a video signal sent from the solid-state imaging device 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 an output end of the video signal processing unit 21, and an endoscope 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 face of the light guide fiber bundle 4 is disposed between the incident end of the light guide fiber bundle 4 and the light source lamp 22. Have been. A movable diaphragm is provided between the light source lamp 22 and the condenser lens 24 so that the area of the illumination light beam incident on the light guide fiber bundle 4 can be changed by interrupting the illumination light path therebetween by an arbitrary amount. The movable diaphragm 25 is driven by a step motor 26. Reference numeral 23 designates a fixed filter such that three color filters of red (R), green (G), and blue (B) are sequentially inserted into the illumination optical path in order to perform illumination for so-called RGB plane sequential imaging. This is an RGB rotation filter driven to rotate at a speed. A lamp control circuit 27 for driving the light source lamp 22, an aperture drive circuit 28 for driving the movable aperture 25, and a rotary filter drive circuit 29 for driving the RGB rotary filter 23 are provided in the light source device / video processor 20. Microcomputer (microcomputer) control unit 30
The operation is controlled by. FIG. 2 shows a movable diaphragm 25, in which a thin plate is bent into a U-shaped cross section, and a rotating shaft 251 connected to the center of the bottom surface is arranged perpendicular to the illumination optical axis. It is designed to be driven to rotate. FIG. 3 shows a state in which the movable stop 25 is viewed from the direction of the illumination optical axis. As shown in FIG. 3, when the plate surface of the movable stop 25 is parallel to the illumination optical axis. The illumination light path L is hardly obstructed. From this state, the illumination light path L corresponding to the rotation angle of the movable diaphragm 25 driven by the step motor 26 is set.
Is gradually blocked, and the illumination light flux incident on the light guide fiber bundle 4 is reduced. FIG. 4 shows the aperture driving circuit 28, which includes a pulse control circuit 281 and a motor driving circuit 282. The pulse control circuit 281 includes an instruction signal for instructing either forward rotation for closing the movable aperture 25 or reverse rotation for opening the movable aperture 25 from the microcomputer control unit 30 via an input / output port 41 described later, and a drive pulse signal. Then, a drive pulse to be given to the step motor 26 is set. Then, the motor drive circuit unit 282 outputs a drive pulse for driving the step motor 26 according to the pulse signal input from the pulse control circuit unit 281. FIG. 5 shows the microcomputer control unit 30 and its periphery. The microcomputer control unit 30 stores programs and the like on a system bus 32 connected to a central processing unit (CPU) 31 for performing arithmetic processing. The stored read only memory (ROM) 33 and the random access memory (RA)
M) 34 and a real-time clock (RTC) 35 are connected. The CR connected to the system bus 32
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 through the T controller (CRTC) 37 and output to the TV monitor 49. You. 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 input / output ports 38, 39 and 40, respectively.
2 are connected. The panel switch 201 has a movable diaphragm 25
To select whether to automatically or manually adjust the brightness of the observation screen by operating
A hand switch, a brightness up switch, a down switch, and the like, for adjusting the brightness of the observation screen by, for example, 10-step brightness indices from “1” to “10”, are provided. The signal output to the aperture driving circuit 28 is performed through an input / output port 41, and a luminance signal indicating the brightness of the observation screen taken out from the video signal processing section 21 is output to the analog / digital converter 42 by, for example, 0. The signal is converted into a digital signal in the range of ~ 255 and input to the microcomputer control unit 30. Further, by connecting the connector 6 of the endoscope 1 to the light source device / video processor 20, the memory 9 disposed in the endoscope 1 is connected to the microcomputer controller 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 terminal of the input / output port 43 can be switched to a high level or a low level by manually turning on / off. ing. Reference numeral 44 denotes a programmable interval timer (PIT) 44 connected to the system bus 32, the counter output of which is connected to the interrupt terminal of the CPU 31, and changes the counter value set in the counter of the PIT 44. Thus, the time interval of the interrupt processing can be changed. In the first embodiment of the present invention, the luminance signal of the video signal processing section 21 is detected, and the step motor 26 is controlled so that the luminance signal value approaches the reference value determined by the brightness index. A control process for giving a certain number of drive pulses is performed by an interrupt process. The time interval at which the interrupt process is performed is prepared in two ways by changing the counter value set by the PIT 44 in hardware, and one of the long and short time intervals is set in accordance with the type of endoscope used. Time interval. FIG. 6 shows the contents of the main program of the first embodiment, where S indicates a processing step. Here, after performing predetermined initial settings (S1), processing set by the panel switch 201 (S2), input processing from the keyboard 202 (S3), processing related to the lamp control circuit 27 (S4), endoscope The process related to the mirror 1 (S5), the process of displaying the date and time (S6), and the other processes (S7) are sequentially repeated. FIGS. 7 and 8 show the contents of the endoscope-related processing in S5. A variable u1 is stored in the light source device / video processor 20 to store whether or not the endoscope 1 is connected. It is assumed that u1 = 0 is not connected and u1 = 1 is connected. Here, first, it is determined whether or not the endoscope 1 is connected to the light source device / video processor 20 (S).
11) If the endoscope 1 is not connected,
It is determined whether or not the connection is established (S1
2). Thereby, the moment when the endoscope 1 is connected is detected. Therefore, when the endoscope 1 is not connected, the process is terminated as it is. When the endoscope 1 is connected, the process ends.
u1 is set to 1 (S13), and it is determined whether the endoscope 1 is for a digestive organ (S14). According to the determination, when the endoscope 1 is for a digestive organ, the counter of the PIT 44 is set to n = N1 (S1).
5) If the endoscope 1 is not for a digestive organ, the counter of the PIT 44 is set to n = N2 (S16), the endoscope name is displayed on the TV monitor 49 (S17), and the process is terminated. The counter value of the PIT 44 is, for example, PIT
44 clock inputs are 12 kHz, N1 = 360, N2
= 540, 0.03 in the case of a digestive endoscope
Interrupt processing is executed once per second, and in the case of an endoscope other than for digestive organs, interrupt processing is executed once every 0.045 seconds. If the endoscope 1 is connected in S11, it is determined whether or not the endoscope 1 is disconnected (S18). Thus, the moment when the endoscope 1 is removed from the light source device / video processor 20 is detected. If the endoscope 1 is still connected, the process is terminated as it is. If the endoscope 1 is disconnected, u1 is set to 0 (S19), and the endoscope name is deleted from the TV monitor 49 ( S20) End. FIG. 9 shows an interrupt for controlling the operation of the step motor 26 for driving the movable diaphragm 25 for automatically adjusting the brightness of the endoscope observation screen to always correspond to the set brightness index. This shows the contents of the processing. The interruption time interval is determined by the endoscope 1 used as described above.
Depends on the type. In this interrupt processing, first, a luminance signal from the video signal processing unit 21 is input (S21), and the luminance signal value is compared with a reference value based on a brightness index (S22). If the difference is within the allowable range and the brightness of the observation screen matches the brightness index,
The interrupt processing is terminated as it is (S23). If the difference between the luminance signal value and the reference value is larger than the allowable value, it is determined whether the luminance signal value is larger or smaller than the reference value (S24). A forward rotation signal is sent to the aperture drive circuit 28 to drive the movable aperture 25 in the closing direction (S25), and when the luminance signal is smaller, the aperture drive circuit 28 reversely drives the movable aperture 25 in the opening direction. A signal is sent (S26). Then, a plurality of predetermined drive pulses (for example, pulse number 3) are given to the step motor 26, and the process ends (S27). In this way, as shown in FIG. 10, when the digestive endoscope is used, the object to be observed is wide and the distance to the subject frequently changes greatly. , 0.03 seconds, a quick response speed can be obtained for the drive control of the movable diaphragm 25. In the case of an endoscope other than a digestive organ, the observation target is narrow and the change in the distance to the subject is not large. In response to this, control is performed with an emphasis on preventing hunting of the movable diaphragm 25 by interruption processing every 0.045 seconds. FIGS. 11 to 13 are flow charts of control processing according to the second embodiment of the present invention. In this embodiment, the control processing for applying a fixed number of drive pulses to the step motor 26 is not an interrupt processing. This is performed in a normal repetition loop process. A plurality of types of time intervals at which the control processing for the step motor 26 is performed are prepared by software without using the PIT 44, and an appropriate time interval is set by turning on / off the dip switch 11 which is manually operated. I have to choose. FIG. 11 shows the contents of the main program of the second embodiment.
37 aperture control processes are added between the process of displaying date and time (S6) and other processes (S7). FIG. 12 shows the contents of the endoscope-related processing in S35 of the second embodiment. Like the first embodiment, FIG.
The variable u1 is used to store whether or not the endoscope 1 is connected to the light source device / video processor 20. Here, it is first determined whether or not the endoscope 1 is connected to the light source device / video processor 20 (S
41) When the endoscope 1 is not connected, the endoscope 1
In order to detect the moment when is connected, it is determined whether or not the connection has been made next (S42). When the endoscope 1 is not connected, the process is terminated. When the endoscope 1 is connected, the process ends.
u1 = 1 (S43), the endoscope name is displayed on the TV monitor 49 (S44), and the process ends. If the endoscope 1 is connected in S41, the endoscope 1 is
In order to detect the moment of disconnection, it is determined whether or not the connection has been disconnected (S45). If the endoscope 1 is still connected, the process is terminated. If the endoscope 1 is disconnected, u1 is set to 0 (S46), and the endoscope name is deleted from the TV monitor 49 ( S47) End. FIG. 13 shows the contents of the aperture control process in S37 of the second embodiment. The variable c is used as a counter, and c = c + 1 every time the processing loop of FIG.
Is added to c. In this process, first, 1 is added to c (S51), and then the on / off state of the dip switch 11 is determined (S52). When the dip switch 11 is off, the remainder is obtained by dividing the counter c by a constant N1 (S53), and when the dip switch 11 is on, the remainder is obtained by dividing the counter c by a constant N2 (S5).
4). If the remainder is not 0, the flow shifts to other processing of S38 (S55), and only when the remainder is 0,
The process of applying a drive pulse to the step motor 26 is performed in the same manner as the interrupt process of FIG. 9 (S56). In this case, assuming that 0.003 seconds are required for one round of the loop processing in FIG. 11, if N1 = 10 is set, the step motor 26 driving processing in S56 becomes 0.03 seconds.
It is performed every second and 0.045 if N2 = 15 is set.
It is performed every second. Therefore, for example, normally, the dip switch 11 is normally turned off to perform control without delay of the response of the movable diaphragm 25, and the movable diaphragm 25 is likely to be hunting immediately after the mechanism of the movable diaphragm 25 is changed or the light source lamp is replaced. If
Hunting can be prevented by turning on the dip switch 11. By providing a plurality of dip switches 11 or using a rotary type dip switch, the switching state is divided into three or more cases, and the constant N (N1, N2...) Is changed for each case. Thus, the stepping motor 26 can be used in accordance with the endoscope used, the operating conditions, the variation in the aperture mechanism system, or the operator's preference.
The optimal time interval of the drive control can be finely selected. The present invention is not limited to the above-described embodiment. For example, the control process for giving a drive pulse to the step motor 26 is performed by an interrupt process or a loop process. Regarding whether to set by hardware or software, and to select the type of the time interval by endoscope type or dip switch, any combination may be used. According to the present invention, the time interval of the control process for giving a drive pulse to the step motor for driving the movable diaphragm can be selected from a plurality of time intervals, so that it is used. Depending on the type of endoscope and usage conditions,
The response speed can be made as fast as possible without causing hunting of the movable diaphragm. Even if the mechanism of the movable diaphragm changes parts, control processing can be performed without changing software and hardware. Can be changed to an appropriate interval in which hunting does not occur.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an entire configuration of an embodiment. FIG. 2 is a perspective view of a movable diaphragm according to the embodiment. FIG. 3 is a front view of a movable diaphragm according to the embodiment. FIG. 4 is a block diagram of an aperture driving circuit according to the embodiment. FIG. 5 is a block diagram of a control circuit according to the embodiment. FIG. 6 is a control processing flowchart of the first embodiment. FIG. 7 is a control processing flowchart of the first embodiment. FIG. 8 is a control processing flowchart of the first embodiment. FIG. 9 is a control processing flowchart of the first embodiment. FIG. 10 is a time chart illustrating an example of drive pulse control according to the first embodiment. FIG. 11 is a control processing flowchart of the second embodiment. FIG. 12 is a control processing flowchart of the second embodiment. FIG. 13 is a control processing flowchart of the second embodiment. [Description of Signs] 25 movable aperture 26 step motor 30 microcomputer control unit

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-6-222287 (JP, A) JP-A-8-50250 (JP, A) JP-A-3-118022 (JP, A) JP-A-2- 90132 (JP, A) JP-A-2-34141 (JP, A) JP-A-7-39514 (JP, A) JP-A-6-90900 (JP, A) JP-A-5-207973 (JP, A) JP-A-64-31115 (JP, A) JP-A-63-186619 (JP, A) JP-A-55-125309 (JP, U) JP-A-4-2537 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 23/26 A61B 1/04 362

Claims (1)

(57) [Claim 1] A stepper motor drives a movable stop capable of blocking an illumination light path by an arbitrary amount between a light source lamp and a light guide entrance end face of an endoscope. An aperture control device for a light source device for an endoscope, wherein a control process of giving a plurality of drive pulses to the stepping motor to bring the brightness of an observation screen of an endoscope close to a predetermined value is repeated at regular time intervals. In the above, the time interval of the control processing is set by a manual switch, or
A diaphragm control device for a light source device for an endoscope , wherein a plurality of time intervals can be automatically selected according to the type of endoscope to be used .