JPH11281902A - Electronic endoscope light source device for setting light interception period - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the variance in reduction of the quantity of light by fixing the response time of a light shielding mechanism even in the case of different extents of opening of a stop with respect to an electronic endoscope which sets a light interception period to read out all picture elements. SOLUTION: A light shielding mask 22 having a V-shaped aperture 22A is provided, and not only a light shielding shutter 24 is turned around the angular position of the aperture 22A but also a stop plate 23 is linearly moved from the open side of the V-shaped aperture toward its angular position to set the light interception period as a fixed response time, and therefore, the reduction rate of the quantity of light is fixed. For example, with respect to the signal of a still picture, signals of all picture elements obtained with one exposure by a CCD are read out by utilizing the light interception period, and they are subjected to picture element mixing processing to obtain the still picture which has a stable brightness and a high picture quality. In the case of a moving picture, a picture element mixing signal is generated at the time of read from the CCD in the same manner as conventional.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device for an electronic endoscope, and more particularly to an electronic endoscope for setting a light-shielding period to read out signals of all pixels stored in an image pickup device. The present invention relates to a configuration for adjusting an exposure amount of an image signal.

[0002]

2. Description of the Related Art In an electronic endoscope apparatus, for example, in a CCD (Charge Coupled Device) which is a solid-state image pickup device,
An image signal (video signal) is formed by reading out the electric charge accumulated for each pixel by the photoelectric conversion element.
In the simultaneous type electronic endoscope apparatus, a color filter is arranged for each pixel on the upper surface of the CCD, thereby obtaining a color image.

FIG. 6 shows the arrangement of the above color filters. As shown in the figure, on the imaging surface of the CCD 1, for example, pixels of Mg (magenta), Cy (cyan), G (green) and Ye (yellow) pixels are arranged on odd lines. In the CCD 1, accumulated charges (pixel signals) in pixel units are passed through these color filters.
Is obtained.

According to the conventional mixed reading method,
The accumulated charges of the pixels on the upper and lower lines of the CCD 1 are added and mixed and read. For example, as shown on the left side of FIG. 6, a mixed signal of 0 line and 1 line is obtained for the charge accumulated in the exposure within the first 1/60 second period (vertical synchronization period).
A video signal of an odd field (Odd) such as a mixed signal of two lines and three lines,..., Is read out, and the charge accumulated by the exposure within the second 1/60 second period is shown on the right side of FIG. As shown, a mixed signal of one line and two lines, a mixed signal of three lines and four lines,..., And a video signal of an even field (Even) are read.

Accordingly, the two-line mixed signal of the CCD 1 becomes a signal of one line of the field image, and the odd field signal and the even field signal which are read out by shifting one line are alternately read every exposure within a period of 1/60 second. Is output. These odd and even field signals are interlaced and scanned to form an image of one frame, and this image is displayed as a moving image or a still image on a monitor.

[0006]

However, in the above-mentioned simultaneous type electronic endoscope apparatus, as described above, one type is used.
There is a time lag of 1/60 second between the odd field signal and the even field signal for forming the frame image, and if there is blurring of the endoscope itself or movement of the observed object during this time, particularly There is a problem that the image quality (resolution, color shift, etc.) of the still image is reduced.

Therefore, the present applicant has provided a predetermined light-shielding period, and has adopted an all-pixel reading method in which data of all pixels obtained by the immediately preceding exposure is read out using the light-shielding period. However, in the driving of the light-blocking shutter for setting the light-blocking period, a mechanical (gear or the like) response delay occurs. That is, since a complete light-shielding state is required in the light-shielding period for data reading, the light-shielding shutter is operated slightly before the light-shielding period in consideration of the response time,
In this case, the amount of light at the time of the immediately preceding exposure decreases in the response operation (operation until complete light shielding). In addition, when the amount of light emitted from the light source is adjusted by the aperture mechanism, the response time of the light-blocking shutter changes depending on the opening state of the aperture.
There is a problem that the insufficient light quantity changes.

FIG. 7 shows the relationship between the aperture member of the aperture mechanism and a light-shielding shutter for setting a light-shielding period. For example, an aperture blade 3 and a light-blocking shutter 4 are arranged so as to block a light beam (aperture opening) 100 from a light source. One of the aperture blades 3 is centered on a rotation axis 3A, and the other is a rotation axis. Rotate clockwise around 4A,
Attached to rotate. The aperture blade 3 is driven so that the luminance signal of the video signal is constant. For example, by increasing the light amount at a far point and decreasing the light amount at a near point, a good image can be obtained. I have. Further, the light-shielding shutter 4 is moved so as to completely shield the light beam 100 for 1/60 second by making one rotation at a predetermined rotation speed.

However, in such a configuration, the aperture blade 3
And the light-blocking shutter 4 rotate in the same direction, so that the light-blocking shutter 4
The timing of blocking 00P is different, and the response time for completely blocking the light flux 100P changes.
That is, in FIG. 7, in order to completely block the actual light beam 100P, when the aperture blade 3 is fully opened, the rotation angle θ
1, when the aperture blade 3 is at the position indicated by the solid line, the rotation angle θ2;
When located at the position indicated by the two-dot chain line, the light-shielding shutter 4 moves by the rotation angle θ3, and as a result, the response time changes.

FIG. 8 shows the relationship between the light amount (C) of the light beam 100 and the response time (light amount is plotted on the vertical axis and time is plotted on the horizontal axis). In this figure, the aperture blade 3 is fully opened. , Luminous flux 10
0 when the response time ta1 is 2 mS (se
This is a comparison between the case of c) and the case where the response time ta2 when the diaphragm blade 3 is at the position where the half of the aperture opening 2 is closed and the light beam 100 of the other half is shielded is 1 ms.

When the throttle is fully opened, the response time ta1 is 2 ms.
Is satisfied, the light amount C per unit time when the diaphragm is fully opened is 4
V, if the exposure time (tb) is 1/60 second, usually CCD
The amount of charge stored at 1 is tb × C = 1/60 [ms] × 4 [V] ≒ 66.67 [mVS]. On the other hand, the charge amount in the case of providing the light-blocking period is tb × C− (１ ／) ta1 × C = 1/60 [ms] × 4 [V] when the attenuation line at the response time ta1 is regarded as a straight line.
− (1/2) · 2 [mS] × 4 [V] ≒ 62.67 [mVS], so that the light amount when the light-shielding period is provided is 94% of the normal light amount (6% light amount decrease). , Image brightness is 6%
descend.

On the other hand, when the throttle is half open, the response time ta2 is 1 ms.
If the light amount C at this time is 2 V and the exposure time (tb) is 1/60 second, the amount of charge accumulated in the CCD 1 is usually tb × C = 1/60 [mS] × 2 [V] ≒ 33.33 [mVS], and the charge amount in the case of providing the light shielding period is tb × C− (１ ／) ta2 × C = 1/60 [ms] × 2 [V]
− (1/2) · 1 [mS] × 2 [V] ≒ 32.33 [mVS], so that the light amount when the light shielding period is provided is 97% (3% light amount decrease) of the normal light amount. , The image brightness is also reduced by 3%.

As described above, when the response times ta1 and ta2 are different, the rate of decrease in the amount of photographing light is different, and the decrease in the light amount increases as the response time ta increases, and as a result, the brightness of the image changes. I do.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an electronic endoscope that provides a light-shielding period and reads out all pixels. Is to be constant, and to provide an electronic endoscope light source device for setting a light-shielding period in which a variation in light amount reduction can be eliminated.

[0015]

According to a first aspect of the present invention, there is provided an electronic endoscope light source apparatus for setting a light-shielding period according to the first aspect of the present invention. A light-shielding mask that regulates the range, and a light-shielding member that rotates with the position of the intersection of the V-shape of the opening of the light-shielding mask as the center of rotation is provided. A light-shielding means, and a light-shielding member that moves in a direction substantially orthogonal to the rotation direction of the first light-shielding means,
A second light-blocking means for blocking the V-shaped opening by moving the light-blocking member, wherein one of the first light-blocking means and the second light-blocking means is used as a diaphragm mechanism, and the other light-blocking means is an image sensor. , And is used as a fully-closed light-shielding mechanism for setting a fully-closed light-shielding period for reading out the signals of all the pixels stored in the memory. The second aspect of the present invention is directed to the first aspect.
The light shielding means is used as a fully-closed light shielding mechanism, and the second light shielding means is used as a stop mechanism. According to a third aspect of the present invention, there is provided a pixel-mixing readout method at the time of output of an imaging device for mixing and outputting image signals accumulated in the imaging device between upper and lower lines to form a moving image, and the imaging device in one exposure. The present invention is applied to an electronic endoscope having an all-pixel reading method for reading out the signals of all the pixels stored in the memory using the light-shielding period and forming a still image.

According to the above arrangement, for example, the rotation axis of the fan-shaped light-blocking shutter of the fully-closed light-blocking mechanism is disposed at the position of the V-shaped intersection of the opening of the light-blocking mask. It turns toward. On the other hand, for example, the diaphragm plate of the diaphragm mechanism moves linearly from the V-shaped opening extension side (upper side) to the intersection. According to this, even when the diaphragm plate is moved to any diaphragm position, when the light source light beam is completely blocked, the light blocking shutter always rotates by the V-shaped opening angle, and the light beam blocking time, That is, the response time of the light shielding shutter is constant. As a result, the light quantity shortage caused by the response (response delay) time becomes constant, and the variation in the light quantity decrease at the time of exposure immediately before setting the light shielding period is eliminated.

According to the configuration of the third aspect, a high-quality still image is formed by the all-pixel reading method using the light-shielding period. In this all-pixel reading process, for example, a predetermined (1
The charge accumulated by exposure during the 1/60 second period (vertical synchronization period) of the second period (1/60 second)
(Seconds), the odd lines of the image sensor are read, and the remaining even lines are read in the third (at the next exposure) period, and these data are stored in a predetermined memory. Then, the second period is set as a light shielding period so that the even lines can be read.

That is, if the charges of the next exposure are accumulated during the second period for reading the accumulated charges of the odd-numbered lines, the remaining even-numbered lines cannot be read. Therefore, the second period is a light-shielding period, and the accumulated charges of the even-numbered lines are read in the third period. This gives 1
The signals for all the pixels of the image sensor obtained by the second exposure can be read.

Next, the video signals of the odd-numbered lines and the even-numbered lines stored in the memory are subjected to the phase matching, and then the mixing circuit performs a pixel mixing process between the odd-numbered lines and the even-numbered lines. That is, this pixel mixing process
As a result, a signal equivalent to the pixel mixture readout method at the time of output of the image sensor performed when a signal is output from the image sensor is formed, but the pixel mixture is performed based on data obtained by one exposure. Is different from the pixel mixture readout method at the time of output of the image sensor.

On the other hand, during normal moving image display, the pixel mixture readout method at the time of output of the image sensor is selected, and pixels of two horizontal lines are mixed and read when output from the image sensor as in the conventional case. Therefore, in the case of a moving image, it is possible to obtain an image that faithfully reproduces the movement of the subject or the like by imaging over time.

[0021]

FIG. 1 shows a configuration of an electronic endoscope apparatus to which a light source device according to an embodiment is applied. This electronic endoscope apparatus includes a scope (electronic endoscope) 10. And a light source device or a processor device having an image processing circuit. This scope 10 has a tip as shown in FIG.
CCD 12 with the same color filter as described in
And a light guide 15 for guiding the light of the light source lamp 14 to the tip. Further, a freeze switch 16 for displaying a still image is provided on the operation unit of the scope 10.

A CCD drive circuit 18 for driving the CCD 12 is connected to the CCD 12. A timing generator 19 and a microcomputer (microcomputer) 20 for performing various controls are connected to the drive circuit 18. An operation signal of the freeze switch 16 is input to 20. The CCD drive circuit 18 includes a microcomputer 20
Based on the above control, a timing signal is input, and drive control of a pixel mixed readout method at the time of CCD output for a moving image and an all pixel readout method for a still image is performed.

For example, in the case of this all-pixel reading method,
Two types of pulses are supplied from the CCD driving circuit 18 for reading out the accumulated data for all the pixels accumulated in the CCD 12 in one exposure by dividing the data into odd lines and even lines and also shifting in time. Based on this, control is performed to sequentially and sequentially read out the odd-line signal and the even-line signal from the CCD 12. Incidentally, in the pixel mixed readout method at the time of CCD output, one kind of readout pulse is applied to each line.

On the other hand, in the light source section for supplying light to the light guide 15, the light source lamp 14 and the light guide 15 are provided.
A condensing lens 21 and a light-shielding mask 22 for regulating a light beam are arranged between the light-shielding mask 22 and a V-shaped opening 22A. An aperture plate 23 that moves left and right to adjust the amount of emitted light, and a light-blocking shutter (plate) 24 that rotates to set a complete light-blocking period.
A motor 25 and an aperture control circuit 26 are connected to the aperture plate 23, and a motor 27 and an optical shutter control circuit 28 are connected to the light shielding shutter 24.
The lighting of the lamp 14 is controlled by a lamp driving circuit 29.

The aperture control circuit 26 controls the aperture plate 2 based on a luminance signal obtained by a DVP (39) described later.
3 is driven to adjust the amount of light emitted from the lamp 14. Further, the light-shielding shutter control circuit 28 drives the light-shielding shutter 24 at a predetermined timing after the freeze switch 16 is pressed, and completely blocks light for a predetermined light-shielding period of 1/60 second.

FIG. 2 shows the light-shielding mask 22 and the aperture plate 2.
3 and the configuration of the light shielding shutter 24 are shown. As shown in the figure, a V-shaped (opening angle α) opening 22A is formed in the light-shielding mask 22 so as to block a part of the light source light beam 101, and the light-shielding shutter 24 can block the V-shaped opening. The light-blocking shutter 24 has a rotation shaft 24A disposed at the V-shaped intersection of the V-shaped opening 22A, and the light-blocking shutter 24 rotates about the rotation shaft 24A. On the other hand, the diaphragm plate 23 is attached to the V-shaped opening 22A from the opening expansion side (V-shaped upper side) to the intersection, that is, along the line bisecting the opening angle α, so that the diaphragm plate 23 is movable left and right. Light shielding shutter 2
4 is moved substantially orthogonally.

According to this, no matter what the aperture position of the aperture plate 23 that moves left and right through the V-shaped opening 22A, the light shielding shutter 2 that completely shields the actual light flux 101 is provided.
4 always rotates the V-shaped opening angle α of the opening 22A. Therefore, the response time of the light shielding shutter 24 is always the same.

In FIG. 1, an amplifier 31 comprising an automatic gain circuit (AGC) and the like is provided at a stage subsequent to the CCD 12, and this amplifier 31 has a light quantity shortage caused by the setting of the light shielding period by the light shielding shutter 24. Minutes can also be amplified. The amplifier 31 has a first memory 33 for storing the odd-numbered line image data for reading all pixels via an A / D converter 32, a second memory 34 for storing even-numbered line image data, 1 memory 33
Data as is, and read timing is 1/60
A third memory 35 for phase adjustment and a still image mixing circuit 36 for delaying by a second are provided.

That is, all pixel signals obtained by the CCD 12 are temporarily stored in the memories 33 and 34 in a state of being divided into odd-line data and even-line data. By delaying the line data by 1/60 second, it has the same phase as the even line data stored in the second memory 34. As a result, both image data can be read at the same time, and the next-stage mixing circuit 36 adds and mixes the pixel data of the odd-numbered line of the third memory 35 and the pixel data of the even-numbered line of the second memory 34 (still image). Pixel mixing process). Therefore,
In the case of a still image, a pixel mixture signal equivalent to that of the conventional color difference line sequential mixture readout system is formed by the mixing circuit 36.

FIG. 3 shows the contents of the still image data processed by the circuits from the CCD 12 to the mixing circuit 36 described above. As shown on the left side of the figure, the first memory 33 and the third memory 35 store data of odd lines (1, 3, 5... Lines) of the CCD 12, and as shown on the right side of the figure. The second memory 34 stores data of even lines (2, 4, 6,... Lines).

Both data of these memories 35 and 34 are pixel-mixed in order from the upper side as indicated by the solid line or dotted line arrow by the mixing circuit 36, for example, and are indicated by solid lines as 0 line + 1 line, 2 line + 3 line, ... The addition operation data of 4 lines + 5 lines... Is output as odd field data, and the addition operation data of 1 line + 2 lines, 3 lines + 4 lines, 5 lines + 6 lines. Output as field data.

In FIG. 1, an image switching circuit 38 for switching between a moving image and a still image is provided at a stage subsequent to the mixing circuit 36. In the image switching circuit 38, the A / D is connected to the terminal a for forming a moving image. The output of the converter 32 is supplied through the L line, and the output of the mixing circuit 36 is given to the other terminal b. When the freeze switch 16 is pressed, the terminal a is switched to the terminal b. A digital video processor (DVP) 39 is connected to the image switching circuit 38. In the DVP 39, various processes including gamma correction are performed, for example, a color difference signal and a luminance signal are formed. At the subsequent stage of the DVP 39, a memory for storing data of the odd field and the even field, a D / A converter, and the like are provided.
Output to the monitor via the / A converter.

The embodiment has the above configuration, and its operation will be described with reference to FIG. As shown in FIG. 4A, a timing signal for forming a one-field image in 1/60 second is used as a field O (Odd) / E (Even) signal as in the related art. In the normal state, it is set so as to execute the moving image processing, that is, the pixel mixed reading method at the time of CCD output.
Is located at a position that does not block the light source light flux, and the light source lamp 1
The light from 4 is radiated from the distal end portion through the light guide 15 into the object to be observed.

By this light irradiation, electric charges corresponding to the image light from the body to be observed are accumulated in the CCD 12 at the tip.
This accumulated charge is read out by adding pixels between the upper and lower lines by a drive pulse from the CCD drive circuit 18 and reading out the pixel mixture signal described with reference to FIG. The moving image signal is supplied from the A / D converter 32 to the image switching circuit 38 via the through line L.
The image is supplied to the DVP 39 via the terminal a of the image switching circuit 38. The operation after the DVP 39 is the same as the conventional operation, and a moving image is displayed on the monitor based on the odd and even field signals.

Here, the luminance signal obtained by the DVP 39 is supplied to the microcomputer 20, and the aperture plate 23 is driven by the control of the microcomputer 20 and the aperture control circuit 26, whereby the luminance of the image is kept constant. You.

On the other hand, when the freeze switch 16 of the scope 10 shown in FIG. 1 is pressed, the image switching circuit 38 is switched to the terminal b by the microcomputer 20. Can be switched to Then, for example, as shown in FIG. 4 (B), a little before the rising edge of the O / E signal (t1),
The light shielding shutter 24 closes the light beam 101 for 1/60 second, during which time the output light from the light source unit is shut off as shown in FIG. Therefore, the image data from which all the pixels are read out becomes electric charges accumulated in the CCD 12 by the light output Lt in the 1/60 second period immediately before the light shielding period.

That is, FIG. 4D shows the read pulse P1 of the odd line on the left side of FIG. 3, and FIG. 4E shows the read pulse P2 of the even line on the right side of FIG. Odd line data and even line data are sequentially read from the CCD 12 by the read pulse P1 without the pulse and the read pulse P2 without the pulse at t1. Therefore, the reading of the odd-numbered lines is performed during the light-shielding period (t1 to t2), and the reading of the even-numbered lines is performed during the next period (t2 to t3).

FIG. 4G shows the operation of the electronic shutter. In this case, the accumulated charges in the rising period of the pulse are swept out, and the accumulated charges in the non-rising period are read. Therefore, the above still image data (accumulated charge)
Is the exposure g1 for the exposure time tb after the charge has been swept out.
The charges of all the pixels are read out by the CCD drive circuit 18. Note that the sweeping is omitted in the light-shielding period (t1 to t2) after the exposure g1.

By the way, in the above-mentioned light-shielding period, it is necessary to set a complete light-shielding state so that unnecessary charges are not accumulated in the CCD 12, and for that purpose, control is performed in consideration of a response time. That is, in the light-blocking shutter control pulse of FIG. 4B, a pulse that reverses earlier by the time ta in consideration of the mechanical response delay time (response time) ta of the driving unit (gear or the like) of the light-blocking shutter 24. To form When the light-blocking shutter 24 is driven, the light emitted from the light source unit attenuates in a quadratic curve with the response time ta as shown in FIG. 4C or FIG. The state shifts to a complete light shielding state. Therefore, the light output L for a still image
At t, the light quantity becomes insufficient by the loss of the light quantity La.

As described with reference to FIG. 8, in the related art, the response time ta changes depending on the aperture opening amount. In this example, however, the V-shaped opening 22 is formed in the light shielding mask 22.
A, and the light-shielding shutter 24 is
Is rotated about the V-shaped intersection point of
Regardless of the movement position of 3, the actual light beam 101 is necessarily blocked by the rotation of the V-shaped angle α of the light-blocking shutter 24, and the response time ta of the light-blocking shutter 24 is constant.

FIG. 5 shows the relationship between the light quantity (C) of the light beam 101 passing through the opening 22A and the response time in this example. Here, for example, the insufficient light quantity La1 when the diaphragm plate 23 is fully opened. Comparing the deficient light amount La3 when the diaphragm plate 23 is driven to some extent, even if the light amount C is changed by the diaphragm plate 23, the ratio of the deficient light amount to the entire exposure amount becomes constant due to a constant response time. I understand.

First, when the diaphragm plate 23 is fully opened, the light quantity per unit time C = 4V, and the response time ta = ta1 = 2 ms.
(Sec) and the exposure time (tb) = 1/60 second, the charge amount of the moving image accumulated in the CCD 1 is 6 as in the case of FIG.
6.67 [mVS], and the charge amount of the still image provided with the light shielding period is about 62.67 [mVS]. Therefore, the light amount of the still image is 94% of the light amount of the moving image, and the insufficient light amount La1 is 6% of the whole.

On the other hand, when the diaphragm plate 23 is driven to some extent, the light amount C = 1V, the response time ta = 2 ms, and the exposure time t
Assuming that b = 1/60 second, the charge amount of the moving image accumulated in the CCD 1 is tb × C = 1/60 [mS] × 1 [V] ≒ 16.67 [mVS]. The charge amount of the image is calculated as tb × C− (１ ／) ta × C = 1/60 [ms] × 1 [V] by regarding the attenuation line of the response time ta as a straight line.
− (1/2) · 2 [mS] × 1 [V] ≒ 15.67 [mVS]. Accordingly, also in this case, the light quantity of the still image is 94% of the light quantity of the moving image, and the insufficient light quantity La3 is 6% of the whole, and the ratio of the insufficient light quantity of the still image is the same even if the aperture opening amount is different.

As a result, the variation in the decrease in the amount of light, which has occurred when the light-shielding period is set, is eliminated, and a still image of good brightness (luminance) can be obtained regardless of whether the object to be observed is at the far point or near point. A signal can be obtained. Note that, as described above, the above-described 6% decrease in light amount can be compensated for by the amplifier 31 or the like.

Then, the CCD 1 is controlled by such light amount control.
2, the odd line data thereof is written to the first memory 33 of FIG. 1, and the other even line data is written to the second memory 34 of the still image signal.
The odd line data in the memory 33 is 1/60 in the third memory 35.
With a second delay, the phase of the even-numbered line data in the second memory 34 matches the phase.

Next, each of the data stored in the memories 35 and 34 is subjected to pixel mixing by a mixing circuit 36, and from the mixing circuit 36, as shown in FIG.
.. Are output as odd-numbered (Odd) field data, and the added data of 1 line + 2 lines, 3 lines + 4 lines... Are output as even-numbered (Even) field data.
A still image is displayed on the monitor based on these field data. Since the still image is formed by all pixel data obtained at the same exposure, high image quality is obtained. Therefore, even if the endoscope itself shakes or the subject moves during 1/60 second, it is possible to observe a clear still image with a small influence.

In the above embodiment, the first light shielding means is used for the fully closed light shielding mechanism having the light shielding shutter 24, and the second light shielding means is used for the diaphragm mechanism having the diaphragm plate 23. Alternatively, the second light-blocking means may be used for the fully-closed light-blocking mechanism.

In the above example, the mixed readout method at the time of output by the CCD 12 is adopted for the moving image, and conversely, the movement of the subject and the like are faithfully reproduced. In this moving image, a clear image without blur is pursued. In such a case, the all-pixel reading method using the light-shielding period can be adopted for the moving image forming process.

[0049]

As described above, according to the present invention,
Using a light-shielding mask having a V-shaped opening, for example, the light-shielding shutter is rotated around the V-intersection position of the opening of the light-shielding mask, and the diaphragm plate is linearly moved from the V-shaped opening expansion side to the intersection. Thus, the response time of the light-shielding shutter is constant even when the aperture amounts of the apertures are different, and it is possible to eliminate the variation in the decrease in the light amount. Therefore, even with the method of reading out all pixels using the light-shielding period, an image with stable brightness can be obtained regardless of the imaging distance or the like.

According to the third aspect of the invention, there is an advantage that a high-quality still image with stable brightness can be obtained, while a smooth image can be formed for a moving image with faithful reproduction of motion.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an overall configuration of an electronic endoscope apparatus to which a light source device according to an embodiment of the present invention is applied.

FIG. 2 is a diagram illustrating a configuration of a light shielding plate, a diaphragm member, and a light shielding shutter according to the embodiment.

FIG. 3 is a diagram showing image data processed between the memory of FIG. 1 and the mixing circuit.

FIG. 4 is a waveform diagram showing a signal reading operation when a still image is formed in the embodiment.

FIG. 5 is a diagram illustrating a relationship between a response time of a light-blocking shutter and an insufficient light amount in the embodiment.

FIG. 6 is a diagram illustrating a configuration of a color filter in a conventional CCD and pixel mixture readout.

FIG. 7 is a diagram illustrating a configuration of an aperture blade and a light shielding shutter in a conventional light source device.

8 is a diagram showing a relationship between a response time of a light-shielding shutter and an insufficient light amount in the apparatus of FIG. 7;

[Explanation of symbols]

 1, 12 CCD, 14 light source lamp, 16 freeze switch, 20 microcomputer (control means), 22 light-shielding mask, 22A V-shaped opening, 23 aperture plate, 24 light-shield shutter, 26 aperture control Circuit, 28: Light-shielding shutter control circuit, 33, 34, 35: Memory, 36: Mixing circuit.

Claims (3)

[Claims] A substantially V-shaped opening provided with a light-shielding mask for regulating a light-source light beam passing range, and a light-shielding member that rotates with a V-shaped intersection of the light-shielding mask opening as a center of rotation; A first light-blocking means for blocking the V-shaped opening by turning the light-blocking member; and a light-blocking member moving in a direction substantially perpendicular to the rotation direction of the light-blocking member of the first light-blocking means. And a second light-blocking means for blocking the V-shaped opening by using either one of the first light-blocking means or the second light-blocking means as a diaphragm mechanism, and using the other light-blocking means in the image pickup device. An electronic endoscope light source device for setting a light-shielding period used as a fully-closed light-shielding mechanism for setting a fully-closed light-shielding period for reading out pixel signals. 2. An electronic endoscope light source for setting a light-shielding period according to claim 1, wherein said first light-shielding means is used as a fully-closed light-shielding mechanism, and said second light-shielding means is used as a stop mechanism. apparatus. 3. A mixed pixel readout method at the time of output of an image pickup device for mixing and outputting image signals accumulated in the image pickup device between upper and lower lines to form a moving image, and an image signal accumulated in the image pickup device by one exposure. 2. The light-shielding period according to claim 1, wherein the signals of all the pixels are read out using the light-shielding period and applied to an electronic endoscope having an all-pixels reading method for forming a still image. Electronic endoscope light source device.