JPH10118009A - Light source unit with rotary shutter for endoscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a structure by controlling a motor to realize the operation of holding a rotary shutter at a stop position. SOLUTION: A rotary shutter 20 in which a light passing part 20A formed to secure a light source optical path P and a light shielding part 20B for shielding light are arranged free to rotate and the rotary shutter 20 is rotated by a DC motor 21 to output light with a light shielding period to match a full pixel reading system while the rotary shutter 20 is stopped at a position where light is always outputted to be adapted to the conventional system as well. At the stoppage, when any positional deviation of the rotary shutter 20 occurs, a bias voltage for position correcting operation is supplied to the motor 21 based on control by detection and stoppage control circuits 42 or the like of a PG sensor 32 and a stop sensor 33 to execute a holding operation for returning the rotary shutter 20 to a specified stop position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the control of a light source device with a rotary shutter for an endoscope, which is used for medical or industrial purposes and blocks illumination light for a predetermined period.

[0002]

2. Description of the Related Art An electronic endoscope apparatus or an endoscope apparatus irradiates illumination light from a light source to a body to be observed, such as a body cavity, and observes an image of the body to be observed. In this case, a charge coupled device (CCD) is used as an image sensor. In this CCD, an image signal (video signal) is obtained by reading out the electric charges accumulated in pixel units by the photoelectric conversion element, and an image of the object to be observed is displayed on a display by processing the video signal. Can be.

As a method of reading a video signal from the CCD, for example, a pixel mixed reading method is adopted. This pixel-mixing readout method reads out the electric charge accumulated in the CCD by exposure within 1/60 second (vertical scanning period) while adding upper and lower pixel data, thereby forming an image of one field. It has become.

[0004]

In the above-described pixel mixture readout method, since the upper and lower pixel data are added and mixed as described above, the resolution in the vertical (up / down) direction is almost one.
/ 2, and the vertical resolution decreases. Further, since one frame image (1/30 second) is formed by odd and even field information obtained every 1/60 second, image quality is degraded if motion or blur occurs during obtaining each field image. There is a problem of doing.

In order to solve this problem, a method of reading out all pixels without adding pixel data above and below the CCD obtained by one exposure is considered. That is, with respect to all the pixel data of the CCD accumulated in one exposure, data of an odd line is read first, and then data of an even line is read, or data is read sequentially regardless of odd and even lines. Then, by performing image processing based on these data, a high-quality image can be obtained.

[0006] Then, by this all-pixel reading method, CC
When an image signal is extracted from D, there is a method of increasing the reading speed (for example, double speed), but this method complicates the configuration of the CCD (such as a vertical CCD), doubles the clock frequency, and reduces the cost. There is also a problem. Therefore, the present applicant sets the readout speed to be the same as the conventional one, provides a light-shielding period so as to be set alternately with the irradiation period, and reads out all the pixels. It has been proposed to arrange a rotary shutter and to adopt a configuration corresponding to a conventional system that does not require this light-shielding period.

However, in this light source device, when the light-shielding period is not set, it is necessary to stop the rotary shutter at a predetermined position, and a means for holding the stop is required. Various mechanisms and electric structures can be adopted as the holding means. However, if the holding operation can be realized without disposing such separate mechanisms and electric structures, a simplified configuration will be used. A low-cost device can be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to realize an operation of holding a stop position of a rotary shutter by controlling a motor, thereby making it possible to simplify the configuration. An object of the present invention is to provide a light source device with a rotary shutter for a mirror.

[0009]

In order to achieve the above object, a light source device with a rotary shutter for an endoscope according to the present invention comprises: a light source for emitting illumination light toward an object to be observed; A light-passing part for transmitting light from the light source and a light-shielding part for shielding the illumination light, the rotary shutter being rotatably mounted, a motor for driving the rotary shutter, and a position for detecting the rotational position of the rotary shutter. The rotation of the sensor and the motor is controlled, and the light passing portion of the rotary shutter is stopped at a position where the optical path of the light source is secured. At the time of the stop, the bias voltage for the position correcting operation based on the output of the position sensor And a control circuit for supplying a control signal to the motor and controlling to hold the rotary shutter stop position.

According to the above configuration, the rotary shutter has a light-passing portion formed in, for example, about half (180 degrees) and a light-shielding portion in the other half. , This rotary shutter is 1 /
The rotation is controlled at a speed of one rotation in 30 seconds. Therefore, the light output and the light shielding are repeated about every 1/60 second, so that all the pixels can be read out.

On the other hand, when the conventional method is applied,
The light passage portion of the rotary shutter is stopped at a position where the light source optical path is secured, and the illumination light is always output.
At the time of this stop, a deviation state of the stop position of the rotary shutter is detected by the position sensor, and a bias voltage for a correction operation for returning to the stop position after specifying the rotation direction is applied to the motor. Therefore, the rotary shutter is always held at a position where the light source optical path is secured, and there is no need to arrange a special holding mechanism or the like.

[0012]

FIG. 1 shows the configuration of a light source device with a rotary shutter for an endoscope according to an embodiment.
FIG. 2 shows the configuration of an electronic endoscope apparatus to which the light source device is applied. First, the configuration of the electronic endoscope apparatus will be described. As shown in FIG. 2, the electronic endoscope device is divided into an electronic endoscope as a scope, a light source device, and a processor device.
The light guide 12 is provided up to this
2 is connected to the light source device side via a connector.

Further, a CCD 15 is provided so as to be connected to the objective optical system 14 for observation, and the CCD 15 is connected to a connector circuit section 16. The connector circuit section 16 includes C
A CD driving circuit, for example, a first signal processing circuit for performing processing such as amplification of a video signal, and a scope ID generating circuit 17 for generating a scope ID (scope identification) signal assigned to each electronic endoscope are provided. .

On the other hand, a light source 19 such as a xenon lamp is provided on the light source device side, and a rotary shutter 20 is provided in front of the light source 19. The rotary shutter 20 has a sharp light flux, which will be described in detail later. Rise,
In order to realize the falling, it is constituted by one blade.
The rotary shutter 20 is connected to a DC motor 21 and a light source side control circuit 22 that generate small driving sounds, and a detection unit 23 that detects various rotational positions of the shutter 20.
Is provided, and the control circuit 22 drives the DC motor 21 based on the detection of the detection unit 23.

Further, a second signal processing circuit 25 for performing image processing and a CPU 26 are provided on the processor device side. In the second signal processing circuit 25, various types of processing such as white balance processing and gamma correction are performed. Image processing is performed, and a final signal is supplied to the display 27. CP above
The U26 has a field ID signal generating section for generating a field ID signal for identifying the all-pixel reading method or the pixel-mixing reading method. Generate an ID signal. O (OD) for reading the odd line signal and the even line signal from the CCD 15 as the field ID signal.
D) / E (EVEN) signal (timing signal) is used.

FIG. 3 shows the rotary shutter 2 described above.
0, the shutter 20 is connected to a DC motor 21 by a rotating shaft 29, and a light source optical path P
Is formed at an angle slightly smaller than 180 degrees, and the light shielding portion 20B is formed. The rotary shutter 20 has an FG (Frequenc
In order to perform control, a detection hole 30 and an FG sensor 31 formed at equal intervals are provided, and a PG (Phase Ge) is provided above the rotary shutter 20.
A PG sensor 32 for performing control and a stop sensor 33 for stopping control are provided at a lower position. These sensors 31 to 33 are arranged so as to sandwich the shutter blade, and detect the passage and transmission state of light.

The angle of the light passing area 20A and the angle PG
The sensor 32 and the stop sensor 33 are set so as not to block the light source optical path P during the stop holding operation. That is, when the edge of the light shielding portion 20B (shutter blade) is at the light shielding boundary point Q1 of the PG sensor 32, the other edge is q
When the edge is at the position 1 and the edge of the light-shielding portion 20B is at the light-shielding boundary point Q2 of the stop sensor 33, the other edge is at the position of q2.

In FIG. 1, FG control circuit 35 and PG control circuit 3 are included in the light source side control circuit 22 as constituent circuits.
6, adder circuit (MIX.) 37, mode switching circuit 3
8, a motor driver 39, an ID discrimination (mode discrimination) circuit 40 for inputting the field ID signal, a rotation direction switching circuit 41, and a stop control circuit 42. That is,
FG control circuit 35 to which the detection output of FG sensor 31 is input
Performs a stable rotation speed control of the rotary shutter 20, and the PG control circuit 36, which receives the detection output of the PG sensor 32, outputs a signal synchronized with the O / E signal, the light passing unit 20A and the light shielding unit 20B. The PG control is performed so that the position of.

The ID discriminating circuit 40 is triggered by, for example, the rise of an O / E signal (field ID signal).
It is composed of a monostable multivibrator that outputs a high level. By setting the holding time of the high level to be longer than 1/30 seconds, the high level is maintained. The ID discriminating circuit 40
The high-level signal switches the mode switching circuit 38 to the upper side to set the rotation mode. When the O / E signal is not detected (Low level), the mode switching circuit 38 is connected to the lower side to switch to the stop mode.

The rotation direction switching circuit 41 sets the forward rotation direction (counterclockwise direction in the figure) when the rotation mode is set, sets the reverse rotation direction when the stop mode is set, and the stop sensor 33, based on the switching signals I1 and I2. When a High signal is input from the controller, an operation of switching to the normal rotation direction is performed.
The stop control circuit 42 determines that the stop position is reached when both the PG sensor 32 and the stop sensor 33 are blocked by the shutter 20 and there is no detection output, and stops the DC motor 21 completely. Performs stop hold control.

That is, the control voltage VR is supplied from the stop control circuit 42 to the motor driver 39, and the control voltage VR
Is supplied to the DC motor 21 to perform a correction operation. For example, when the rotary shutter 20 slightly rotates counterclockwise from the stop state in FIG. 3 and the PG sensor 32 outputs High, a reverse-biased bias voltage is applied, and the DC motor 21 is reversely rotated at a low speed. Return to the stop position. Also, the rotary shutter 2
0 rotates slightly clockwise, and the stop sensor 33 is set to High.
When it becomes an output, apply a bias voltage that rotates forward,
The DC motor 21 is controlled to rotate forward at a low speed and return to the stop position.

The embodiment has the above configuration, and its operation will be described below with reference to FIGS. In this example, the rotation mode is set in the all-pixel reading method,
The stop mode is set in the pixel-mixing readout method. In this all-pixel reading method, in the CCD 15 of FIG.
In order to alternately obtain the odd (ODD) line video signal (accumulated charge) and the even (EVEN) line video signal, FIG.
The O / E signal shown in (A) is used. This O / E
The signal is a rectangular wave signal that rises and falls repeatedly every 1/60 second.

Since the O / E signal is not required in the conventional pixel mixed readout system, it is used as a signal indicating the selected state of the rotation mode. Will be That is, the CPU 26 determines whether the pixel mixture readout method or the all-pixels readout method is adopted from the scope ID signal on the electronic endoscope side, and if the all-pixels readout method is adopted, the rotation mode is set. An O / E signal is output to the ID discrimination circuit 40 as the indicated field ID signal.

Then, as shown in FIG.
When the O / E signal of FIG. 5A is input to the ID discrimination circuit 40, the High signal of FIG.
The mode switching circuit 38 is connected to the addition circuit 37 side by a signal, and is switched to the rotation mode. In this rotation mode, the motor driver 39 controls the driving of the DC motor 21 so that the rotary shutter 20 is rotated 1/30.
It rotates at a speed of one rotation per second, and this rotation state is detected by the FG sensor 31 and the PG sensor 32.

The outputs of these sensors 31 and 32 are supplied to an FG control circuit 35 and a PG control circuit 36, and the outputs of these control circuits 35 and 36 are output to a motor driver 39. According to the FG control, the rotary shutter 20
Is rotated in the stable forward rotation direction (counterclockwise direction in the figure), and according to the PG control, as shown in FIG.
In synchronization with the O / E signal of FIG. 6 (A), light-shielding and light passage are accurately repeated at a period of 1/30 second, and the opening / closing position is controlled about every 1/60 second.

In this way, the light from the light source is emitted every 1/30 second, and emitted from the distal end of the electronic endoscope into the body to be observed. In the all-pixel readout method of this example, about 1
By one exposure in / 60, the accumulated charges (data) of all the pixels obtained by the CCD 15 are read out in odd lines and even lines. This state is shown in FIG. 6C. For example, with respect to the data obtained at the time of the n-th exposure in FIG. 6B, the odd (ODD) line data (n) is read in the next light-shielding period. The even-number (EVEN) line data (n) rises during the light-shielding period, and the output transmission is completed during the (n + 1) -th exposure period. Since the data of the CCD 15 at the time of reading the even-numbered line data is transferred to the transfer line during the light-shielding period, there is no problem in the charge accumulation at the (n + 1) -th exposure.

FIG. 7 shows the image data of this all-pixel readout. The image data on the CCD 15 in FIG. 7A is the data of the odd-numbered line shown in FIG. The data is read out separately from the data of the even-numbered line shown in FIG. 7C, and after being subjected to predetermined image processing, is displayed on the display 27. Here, the odd-numbered and even-numbered line data may be directly processed as odd-numbered and even-numbered field data. In this case, there is an advantage that the vertical resolution is improved as compared with the related art. Further, the odd-numbered and even-numbered line data are temporarily stored in a memory, the odd-numbered lines and the even-numbered lines are alternately read, and signals are sequentially formed, thereby obtaining an image having a high vertical resolution. Also in this case, since processing is performed based on all pixel data obtained by one exposure using the rotary shutter, there is an advantage that image quality deterioration due to motion or blur can be reduced.

Next, when the electronic endoscope employs the conventional pixel mixture readout method, the O / E signal of FIG. 5A is not output to the ID discriminating circuit 40, and the output of this circuit is ,
As shown in FIG. 5B, the state changes to the low state. Accordingly, by connecting the mode switching circuit 38 to the stop control circuit 42, the mode is switched to the stop mode, and the stop of the motor 21 is controlled.

FIG. 4 shows the operation of the rotary shutter 20 in the stop mode. At the time of transition to the stop mode, first, the operation of aligning the light passage section 20A with the light source optical path P is performed. That is, in the stop mode, the rotation direction is switched in the reverse direction (clockwise in the figure) by the rotation direction switching circuit 41 (I1, I2), and as shown in FIG. When the light blocking portion 20B (shutter blade) does not exist at the position and the output of the PG sensor is High, as in FIG. Reverse operation.

On the other hand, as shown in FIG. 4B, the light-shielding portion 20B does not exist at the position of the stop sensor 33, and FIG.
Similarly to (D), when only the stop sensor output is High, DC based on the output of the stop control circuit 42
The motor 21 rotates forward at a low speed. Such forward rotation,
The reverse operation is repeated several times, and the rotary shutter 2
The light transmitting portion 20A of 0 is set at a position where the light source optical path P is secured, and the light source light is always radiated into the body to be observed. When the rotary shutter 20 is on the opposite side, the PG sensor 32 and the stop sensor 33 may be in a shielded (Low) state. In this state, finally, the output of the PG sensor 32 becomes the Low state. Also in this case, the control to the stop position can be performed by executing the reverse rotation operation.

Since the rotary shutter 20 is not provided with a special locking means, the rotary shutter 20 may deviate from its stop position due to vibration or the like. In order to eliminate this deviation, the control circuit 22 is stopped. 4 (C), (D) and FIG.
(C) to (G). That is, as shown in FIG. 4C, when the rotary shutter 20 rotates counterclockwise and the light blocking portion 20B deviates from the position of the PG sensor 32, as shown in FIG. Is Hi
gh, and as shown in FIG. 5 (F), the reference voltage Vre
A control voltage VR slightly higher than f is supplied to the motor driver 39.

In this stop mode, as shown in FIG. 5 (E), the rotation direction is reversed by the rotation direction switching signals I1 and I2, so that as shown in FIG. Performs reverse operation at a low speed for a predetermined time. The time of this reverse operation is shown in FIG.
Is set in consideration of the amount of rotation for returning to the normal position, whereby the rotary shutter 20 is almost accurately returned to the normal stop position.

As shown in FIG. 4D, when the rotary shutter 20 is displaced clockwise and the light blocking portion 20B is displaced from the position of the stop sensor 33, as shown in FIG. The sensor output becomes High, and a control voltage VR slightly lower than the reference voltage Vref is supplied to the motor driver 39, as shown in FIG.
The output of the stop sensor 33 is also output to the rotation direction switching circuit 41, and the rotation direction is switched to normal rotation as shown in FIG.
As shown in (1), the DC motor 21 rotates forward at a low speed for a predetermined time. Therefore, also in this case, the rotary shutter 20 rotates by a predetermined amount and returns to the normal stop position.

In the above stop mode, the following pixel mixture reading is performed. That is, as shown in FIG. 6 (D), the light source light is always in the output state, and
FIG. 6 shows the CCD 15 data obtained by the exposure every second.
As shown in (E), the pixel mixture signal is read as information of the odd field and the even field.

FIG. 8 shows image data of this pixel mixture readout. For example, (0 line + 1 line)
Odd field signals such as (2 lines + 3 lines), (1 line + 2 lines), (3 lines + 3 lines)
An even field signal such as 4 lines) is read. These video signals are also subjected to predetermined image processing and displayed on the display 27.

[0036]

As described above, according to the present invention,
A light source device for rotating a rotary shutter having a light-passing portion and a light-shielding portion formed by a motor. The light-passing portion stops the rotary shutter at a position where a light source optical path is secured. Since the bias voltage for the correction operation is supplied to the motor to control the holding of the rotary shutter stop position, the operation of holding the rotary shutter stop position can be realized by controlling the motor, and a separate holding mechanism and the like can be provided. Without providing, it is possible to simplify the configuration. Moreover, there is an advantage that image formation by both the high-quality all-pixel reading method and the conventional reading method can be realized at low cost, and the application of the light source device can be expanded.

[Brief description of the drawings]

FIG. 1 is a circuit block diagram showing a configuration of a light source device with a rotary shutter for an endoscope according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of an electronic endoscope apparatus to which the light source device with a rotary shutter shown in FIG. 1 is applied.

FIG. 3 is a diagram illustrating a configuration of a rotary shutter in FIG. 1;

FIG. 4 shows a stop operation of the rotary shutter in the stop mode [FIGS. (A) and (B)] and a stop holding operation [FIG.
(D)].

FIG. 5 is a timing chart showing an operation of the light source device of the embodiment.

FIG. 6 is a timing chart showing image processing of an all-pixel reading method and a pixel-mixing reading method in the embodiment.

FIG. 7 is an explanatory diagram showing image data obtained by an all-pixel reading method according to the embodiment;

FIG. 8 is an explanatory diagram showing image data obtained by the pixel mixture readout method according to the embodiment;

[Explanation of symbols]

15: CCD, 19: light source, 20: rotary shutter, 20A: light transmitting part, 20B: light shielding part, 21: DC motor, 22: light source side control circuit, 26: CPU, 31: FG sensor, 32
... PG sensor, 33 ... Stop sensor, 40 ...
ID discrimination circuit, 42... Stop control circuit.

Claims (1)

[Claims] 1. A light source for emitting illumination light toward an object to be observed, a light passing portion for passing light from the light source, and a light shielding portion for shielding the illumination light are formed and rotatably mounted. A rotary shutter; a motor for driving the rotary shutter; a position sensor for detecting the rotational position of the rotary shutter; and a position for controlling the rotation of the motor and allowing the light passage of the rotary shutter to secure an optical path of the light source. At the time of this stop, the bias voltage for the position correction operation is supplied to the motor based on the output of the position sensor,
A light source device with a rotary shutter for an endoscope, comprising: a control circuit that controls holding of a rotary shutter stop position.