JPH09261533A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the light source device provided with an automatic dimmer function to which an optimum response speed is set even with different combinations of an image pickup element and a signal processing system and in which a level of an EE signal is independent of a setting value of the reference. SOLUTION: A light from a lamp 8 is emitted to a light guide 6 of an electronic endoscope 2 via an aperture 19 and the light reflected in an object is given to a DC processing circuit 14 in a video processor 4 via an image pickup system, from which an EE signal corresponding to the lightness is generated. A comparison output between the EE signal and a reference signal REF is used for a DC dimmer control loop in which an emitted luminous amount is controlled by the aperture 19. Furthermore, a correction value arithmetic section 37 calculates a correction value based on data read from a memory means storing a light emission circuit by the aperture 19 and a gain characteristic by an EE signal generating system and a position change in the aperture 19 is detected by a damper coil 34 and it is given to a subtractor circuit 32 via a GCA 36 to form a dynamic dimmer control loop thereby obtaining an optimum response speed without changing a DC gain.

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 having an automatic light control function for automatically adjusting the amount of emitted light for illumination according to the brightness signal of a subject image.

[0002]

2. Description of the Related Art In general, some image pickup devices for picking up images have a function of automatically controlling an exposure amount or an illumination light amount by controlling an opening amount of a diaphragm (iris). For example, in Japanese Unexamined Patent Application Publication No. 4-372935, a signal corresponding to brightness is generated from the amount of light incident on an image sensor through a diaphragm, and a comparator circuit compares the signal with a reference value to control the aperture amount of the diaphragm. If within a given range close to the value,
It is disclosed that the overdrive, undershoot, and the like are prevented from occurring by making the aperture drive speed slower than when the speed is out of the range.

Further, in Japanese Laid-Open Patent Publication No. 2-257126, an auto iris system for automatically controlling an exposure amount has a gain when responding in a direction from an aperture to a stop and a gain when responding from an aperture state to an open side. , The former side is lowered to improve the responsiveness.

[0004]

In the above-mentioned conventional example, the image pickup device and its signal processing system are integrated. Therefore, in the case of a system in which these characteristics are different from each other, an appropriate response speed is required. Will be difficult to achieve. For example, Japanese Laid-Open Patent Publication No. 7-148110 discloses an endoscope automatic light control device capable of setting an optimum response speed even when combinations are different.

The endoscope apparatus includes a plurality of types of endoscopes each having an image pickup means, a light source apparatus, a video processor, etc. as its constituent devices. For example, there are endoscopes having different outer diameters depending on the site to be used such as the upper digestive tract or the lower digestive tract. Since these characteristics are different, depending on the combination, there are cases where the response speed of dimming in the endoscope device of the combination becomes faster and cases where it becomes slower.

Therefore, for example, when performing an endoscopic examination in a hospital or the like, a case where the endoscopic apparatus is composed of a common light source device and an endoscope selected according to the examination site to be used, It is conceivable that the light source device side may be selected together with the endoscope that is selected according to the region or the like and always used in a fixed combination.

In the latter case, a large number of endoscope devices must be prepared, which increases the economic burden. On the other hand, the former does not have such a defect, but the response speed of automatic light control changes depending on the combination. As described above, even when the combination is different, the above-mentioned JP-A-7-1 is used.
In Japanese Patent No. 48110, a dimming function is realized so that an optimum response speed can be set.

In this publication, in a loop for controlling the quantity of light by the diaphragm by comparing and outputting the reference value of brightness and the EE signal, the control means for correcting the correction value data stored in the storage means in the actual combination device. Is formed.

Since this control means carries out a DC gain correction using the information of each aperture position, when the reference value is changed, the DC gain changes and the level of the EE signal also changes. Therefore, for example, even when an image is photographed and recorded and the brightness of the image is required and the EE signal is used for photographing, the level of the EE signal also depends on the set value of the reference value. In addition, it is inconvenient that it is necessary to refer to the set value of the reference value.
Therefore, it is desired to obtain an EE signal that uniquely reflects the brightness of the image without depending on the set value of the reference value.

The present invention has been made in view of the above-mentioned points, and it is possible to set the optimum response speed even when the combination is different and to make the EE signal level independent of the set value of the reference value. An object is to provide a light source device having a function.

[0011]

[Means for Solving the Problems] A diaphragm means for increasing / decreasing the amount of emitted light, and a dimming circuit for controlling a diaphragm means by inputting a brightness signal of a subject image output by an observation device for outputting a subject image as an image signal. In the light source device, a first detection unit that detects a change amount of the transmittance of the diaphragm unit, a second detection unit that detects a change amount of the brightness signal of the observation device with respect to a change of the incident light amount, and a first detection unit. By providing the control means for controlling the responsiveness without changing the DC gain of the dimmer circuit according to the outputs of the means and the second detection means, the optimum response speed can be set even when the combination is different, and the EE
Automatic dimming can be performed without the signal level depending on the set value of the reference value.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 shows the configuration of an endoscope system having a light source device according to a first embodiment of the present invention.

An endoscope system 1A shown in FIG. 1 is a light source device according to a first embodiment for supplying illumination light to an electronic endoscope 2 having an image pickup means and a light guide 6 of the electronic endoscope 2. 3A, a video processor 4 that outputs a video signal (image signal) by performing signal processing on the image pickup means, and a monitor 5 that displays a video signal corresponding to a subject image output from the video processor 4. Electronic endoscope 2
The video processor 4 and the monitor 5 form an observation device 10.

The electronic endoscope 2 has an elongated insertion portion, and a light guide 6 for transmitting illumination light is inserted into the insertion portion.
The light guide connector 7 at the rear end of the light guide 6 is detachably attached to the light source device 3A, transmits the illumination light from the lamp 8 in the light source device 3A, and is emitted from the emission end face fixed to the front end portion of the insertion portion. The light is emitted forward through the illumination window to illuminate a subject such as an affected area.

An observation window (not shown) is formed adjacent to the illumination window at this tip, and an optical image of the subject is formed through an objective lens attached to the observation window. A solid-state image sensor 9 such as a CCD is arranged at this image forming position to photoelectrically convert an optical image.

The solid-state image pickup device 9 is connected to a signal cable which is inserted through an insertion portion or the like, and a signal connector 11 at the rear end of the signal cable is detachably connected to the video processor 4 and is a drive in the video processor 4. Circuit 12
By applying the drive signal of 1 to the solid-state image sensor 9, the photoelectrically converted image signal is input to the video signal generation circuit 13 and the DC conversion circuit 14 in the video processor 4.

The video signal creating circuit 13 creates (creates) a standard video signal from the image pickup signal, outputs the standard video signal to the monitor 5, and displays a subject image on the monitor screen. Further, the DC conversion circuit 14 extracts the luminance component of the image pickup signal and, through an integration circuit or the like, generates a DC conversion signal (hereinafter, EE signal) corresponding to the average brightness of the subject image.

Video processor 4 (DC conversion circuit 14 thereof)
EE signal output end of the light source device 3A through the signal cable
By connecting to the EE signal input terminal 39 of
The E signal is input to the second arithmetic unit 17b included in the dimming circuit 16 via the EE signal input terminal 39. The second computing unit 17b and the first computing unit 17a are proportional to the output signal of the light receiving element 18 that receives and detects the amount of emitted light that is supplied or emitted from the lamp 8 to the end face of the light guide 7, that is, the amount of emitted light. The signal I is input.

The illumination light of the lamp 8 is interposed in the middle of the illumination light path, passes through a diaphragm 19 as a diaphragm means for increasing or decreasing the light quantity, and is emitted to the incident end surface of the light guide 6 as an emitted light quantity of the light source device 3A during an endoscopic inspection. Supplied. Further, when the dimming circuit is set, the half mirror 21 is provided in the illumination optical path in front of the incident end face of the light guide 6, so that the emitted light amount is the transmitted light amount on the light guide 6 side and the reflected light amount is received. It is detected by the element 18 and is output to the first calculation unit 17a and the second calculation unit 17b.

A diaphragm 19 for increasing / decreasing the amount of light emitted from the lamp 8 to the light guide 6 side of the electronic endoscope 2 has its base end portion connected to the rotary shaft of the motor 22 and driven by the motor drive circuit 23. The diaphragm 19 is rotated along with the rotation of the motor 22 which is rotationally driven according to the signal, and the opening area on the tip side of the diaphragm 19 on the illumination optical path changes, and the opening area of the diaphragm 19 is passed (or transmitted). Only the illumination light is supplied to the light guide 6.

Therefore, the amount of light emitted to the light guide 6 side is determined according to the rotation position (rotation angle) of the diaphragm 19. The rotational position of the diaphragm 19 is detected by, for example, a potentiometer 24 for detecting the diaphragm position, and a signal (also referred to as a diaphragm position signal) POT output from the potentiometer 24 is the first computing unit 1.
7a and the comparison circuit 25.

The comparator circuit 25 is supplied with an integral value of an integrating circuit 27 for integrating the pulse output from the counter circuit 26 (as a reference value for setting), and the diaphragm position signal P is inputted.
After being compared with OT, the output of the comparison circuit 25 is applied to one contact a of the changeover switch 28. That is, the integrating circuit 27 is provided at one input terminal (which becomes the reference side) of the comparing circuit 25.
An integral value that gradually increases from 0 is input via.

The arithmetic output of the first arithmetic unit 17a is stored in the first memory 29a using the value of the signal POT output from the potentiometer 24 as an address signal, and the arithmetic output of the second arithmetic unit 17b is the value of the EE signal. It is stored in the second memory 29b as an address signal.

The first calculation unit 17a performs a calculation for obtaining a change amount of the emitted light amount (actually emitted through the diaphragm 19) at each diaphragm position, and the calculation result is stored in the first memory 29.
Then, the aperture position is stored in the first memory 29a as an address. That is, the first calculation unit 17a forms a first detection unit that detects a change amount of the emitted light amount by the diaphragm 19. The first detecting means has the following configuration.

The first detecting means is a light receiving element 18 as a light quantity detecting means for detecting the light quantity I at each aperture position when sequentially moving from the fully open position by a constant amount of movement, and the current aperture position and one position before. Light amount difference I (N-1) -I between aperture positions
(N), and the first computing unit 17a as a computing means for computing the ratio with the light amount I (N) at the current diaphragm position, and the ratio obtained by this computing means changes the transmittance of the diaphragm 19 at the current diaphragm position. And a first memory 29a as a storage means for storing the quantity.

Further, the second arithmetic unit 17b performs an arithmetic operation for obtaining the ratio of the variation of the emitted light quantity to the variation of the EE signal at each EE signal level, outputs the arithmetic result to the second memory 29b, and outputs the EE. The signal level is stored in the second memory 29b as an address.

In other words, the second arithmetic unit 17b forms a second detecting means for detecting the change amount of the EE signal with respect to the change amount of the incident light amount incident on the solid-state image pickup device 9. The second detecting means has the following configuration.

The second detecting means is a light-receiving element 18 as a light quantity detecting means for detecting the light quantity at each aperture position when sequentially moving from the fully open position by a constant movement amount, and the observation device 10 at the current aperture position. Difference EE (N-1) -EE between the brightness signal EE (N) output from the observation device 10 and the brightness signal EE (N-1) output from the observation device 10 at the preceding aperture position.
(N) and the difference I (N-1) -I (N) in the amount of light between the current diaphragm position and the immediately preceding diaphragm position are obtained, and EE (N-1) -E
The second arithmetic unit 29b as an arithmetic means for obtaining the ratio of E (N) and I (N-1) -I (N), and the ratio obtained by this arithmetic means are used as the brightness signal EE ( In the case of N), the second memory 29b is configured as a storage unit that stores the change amount of the brightness signal of the observation device 10 with respect to the change amount of the incident light amount.

The EE signal is also input to the comparison circuit 30 and compared with the reference signal REF output from the host CPU 31. The comparison output compared by the comparison circuit 30 passes through the subtraction circuit 32 and further through the changeover switch 28. Then, it is input to the motor drive circuit 23.

The changeover switch 28 is a host CPU 31.
The switching is controlled by the dimming setting signal SET from (1), the contact b is turned on when the normal automatic dimming is used, and the contact a is turned on by the dimming setting signal SET when the dimming is set.

When the dimming is set, the host CPU 31 sends a dimming start signal STA to the counter circuit 26.
RT is output, and the output of the counter circuit 26 is the integration circuit 27.
To be input to.

The host CPU 31 uses the initial setting signal output by operating the initial setting switch of the operation panel 33 to set the dimming setting signal SET and the dimming start signal ST.
Output ART. Further, the level of the reference signal REF output from the host CPU 31 can be variably set by operating the light amount setting switch of the operation panel 33.

In this embodiment, by forming a dynamic (frequency-wise) control loop or control means that operates when the light quantity by the diaphragm 19 changes, the DC gain is not changed (that is, the reference signal is not changed). The EE signal reflecting the brightness is obtained without depending on the set value of REF), and the automatic light control means is configured.

Therefore, in order to detect the rotation of the motor 22 (corresponding to the occurrence of a change in the light amount by the diaphragm 19),
A damper coil (braking coil) 34 that is coupled to the winding of the motor 22 by electromagnetic induction is provided.
After the output signal of No. 4 is integrated by the integrating circuit 35, the integrated value is supplied to a gain control amplifier (hereinafter abbreviated as GCA) 36 whose amplification degree is controlled according to the signal level applied to the gain control end. Is entered.

The GCA 36 has information on the change amount of the emitted light amount by the diaphragm 19 read from the first memory 29a and the second memory 29b and the EE for the change amount of the emitted light amount.
A correction value calculation unit 3 that performs a calculation for dynamically correcting the gain of the dimming feedback loop from the change amount of the EE signal of the signal generation system, that is, the information of the gain G of the imaging system and its signal processing system.
The output value of 7 is applied to the gain control end, and the integrated value is amplified with an amplification degree according to the value applied to the gain control end.
The output of the GCA 36 is input to the subtraction circuit 32, and the output value of the GCA 36 is subtracted from the value output from the comparison circuit 30 by the subtraction circuit 32 and output to the motor drive circuit 23 side.

The correction value calculator 37 controls the gain of the GCA 36 according to the above two pieces of information, outputs the value output from the GCA 36 to the subtraction circuit 32, and subtracts the deviation amount of the EE signal from the reference signal REF. The responsiveness control is performed so as to correct (dynamically when the light amount changes) by subtraction by 32. The GCA 36 basically performs the same function as a multiplication circuit that performs multiplication, and a multiplication circuit may be used.

For example, when the change amount of the emitted light amount at a certain diaphragm position is large and the gains of the image pickup system and the signal processing system are large, the correction value calculation unit 37 sets the amplification degree of the GCA 36 accordingly. The correction value to increase is GC
By outputting to A36 and subtracting by the subtraction circuit 32,
A calculation is performed to output a correction value that corrects such characteristics.

As described above, in this embodiment, since the control loop for dynamically controlling the response is provided so as not to affect the DC gain, the brightness corresponding to the set value indicated by the reference signal REF is set. Dimming.

In this case, by dynamically correcting the characteristics of the quantity of light emitted by the diaphragm 19 and the characteristics of the image pickup system and the signal processing system (DC converting circuit 14) by a dynamic control loop which operates when the quantity of light changes. In terms of direct current, the EE signal is proportional to the reference signal REF and is not affected by the correction.

Next, the operation of this embodiment will be described. The light source device 3A is connected to the actually used electronic endoscope 2, the video processor 4, etc., and in order to set the automatic light control function in this combination, the initial setting switch of the operation panel 33 is operated, and the initial setting signal is set. To the host CPU 31.
The host CPU 31 sets the dimming setting signal SET to "H" so that the contact a of the changeover switch 28 is turned on,
Moreover, the dimming start signal START is output to the counter circuit 26. Further, the half mirror 2 is driven by a mirror driving means (not shown) whose operation is controlled by the host CPU 31.
1 is interposed in the optical path in front of the light guide 6.

The counter circuit 26 activated by the dimming start signal START outputs a pulse to the integrating circuit 27,
The output value of the integrating circuit 27 obtained by integrating this pulse and converting it into a direct current is input to the comparing circuit 25 as a reference signal, and the integrated value gradually increases from 0.

The signal POT of the potentiometer 24 representing the rotational position of the diaphragm 19 is also input to the comparison circuit 25,
The comparison output of the comparison circuit 25 (the amount of deviation including the polarity from the integrated value) is input to the motor drive circuit 23 via the changeover switch 28. Here, the value of the signal POT is set to be small when the diaphragm 19 is on the fully open side and to be large on the fully closed side.

The motor 22 is rotationally driven by the rotation direction corresponding to the polarity of the deviation amount and the rotation amount corresponding to the absolute value of the deviation amount. In this way, the signal POT of the potentiometer 24 is controlled by the negative feedback loop so as to match the output value of the integrating circuit 27.

The output value of the integrating circuit 27 is initially 0,
Correspondingly, the aperture amount of the diaphragm 19 or the transmitted light amount of the diaphragm 19 is maximum and the aperture amount is 0, and as the output value of the integrating circuit 27 increases, the aperture amount or the transmitted light amount of the diaphragm 19 follows this. Decrease gradually and throttle from fully open to fully closed 19
Will be driven sequentially. Therefore, the signal I detected by the light receiving element 18 via the half mirror 21 with the diaphragm 19 fully opened has the maximum value Imax.

During this time, the amount of light emitted from the diaphragm 19 (from the light source device 3A) is partially (specifically, 5) when the diaphragm 19 is in the diaphragm position or the aperture position.
0%) is reflected and the remaining transmitted light is supplied to the light guide 6, and the reflected light from the portion illuminated by the illumination light emitted from the tip of the light guide 6 is received by the solid-state image sensor 9. After photoelectric conversion, it is input to the video signal creation circuit 13 and the DC conversion circuit 14 of the video processor 4. The DC conversion circuit 14 generates an EE signal corresponding to the brightness of the average value of the light received by the solid-state image sensor 9, and the EE signal is generated.
The signal is input to the second calculation unit 17b.

On the other hand, the light reflected by the half mirror 21 is received by the light receiving element 18, and its output value photoelectrically converted, that is, the signal I proportional to the amount of emitted light, is given to the first and second arithmetic units 1.
It is input to 7a and 17b. The signal POT of the potentiometer 24 is also input to the first calculating unit 17a, and the first calculating unit 17a calculates the change amount (ΔI / I (N)) of the passing light amount of the diaphragm 19 with respect to each diaphragm position (that is, the signal POT). First, using the signal POT of the diaphragm position as an address
It is stored in the memory 29a.

Here, ΔI reaches the light quantity I (N) at the stop position at that time and the light quantity I (N) at the stop position 1
It represents the difference or change from the light amount I (N-1) at the aperture position before the step. That is, ΔI = I (N-1) -I
Indicates (N) (when not standardized).

Further, the second calculation section 17b causes the change amount Δ of the EE signal with respect to the change amount ΔI of the signal I proportional to each emitted light amount.
E, that is, the gain G (= ΔE / ΔI) of (the DC conversion circuit 14 of) the video processor 4 is obtained, and this gain G (or G (EE) which is a function of the EE signal)
The change amount of the EE signal is stored in the second memory 29b by using each EE signal level as an address.

Here, ΔE is the EE signal EE at that time.
The difference or change between (N) and the EE signal (N-1) one step before reaching the EE signal EE (N) is shown.
That is, ΔE = E (N−1) −E (N) is represented. In addition,
The ΔE may be standardized by the maximum EE signal level EEmax.

These processes are performed until the aperture 19 is fully closed, and after a predetermined time required for these processes has elapsed, the host CPU 31 releases or sets the dimming setting signal SET to "L", and the contact b of the changeover switch 28 is reached. Is switched on, the half mirror 21 is retracted from the inside of the optical path to the outside of the optical path, the automatic light adjustment setting is completed, and the automatic light adjustment function can be used. Also, for example, the host C
The PU 31 sets or switches the first memory 29a and the second memory 29b from the write mode to the read mode. Therefore, the first calculation unit 17a and the second calculation unit 17b
Is equivalent to not performing the arithmetic function.

In this state, the endoscope apparatus 1A is configured, and information corresponding to the characteristics of the devices actually used in combination is stored in the first memory 29a and the second memory 29b. The automatic dimming can be performed with optimal response to the characteristics of the endoscope apparatus 1A due to the combination thereof.

In this automatic dimming state, the operator operates the light quantity adjusting switch of the operation panel 33 to set the light quantity adjusting level desired by the operator to the host CPU.
The reference signal REF having the corresponding brightness can be output to the comparison circuit 30 by instructing the reference circuit 31. For example, if the dark image portion is the region of interest, the setting value of the reference signal REF is large, and if the bright image portion is the region of interest, the setting value of the reference signal REF may be small.

The comparison circuit 30 compares the reference signal REF with the EE signal output from the video processor 4, and outputs the comparison output, that is, the deviation amount from the reference signal REF, via the subtraction circuit 32 and the like, to the motor drive circuit 23. Entered in
The amount of light emitted from the diaphragm 19 is changed by rotating the motor 22 in the direction in which the comparison output is reduced.

In this case, the rotation of the motor 22 generates an induced voltage in the damper coil 34 coupled to its winding by electromagnetic induction, and its output is integrated by the integrating circuit 35,
It is input to the GCA 36.

In this GCA 36, when the diaphragm 19 is changed from the first memory 29a and the second memory 29b, information on the change in the emitted light amount at each stop position and the change in the EE signal with respect to the change in the emitted light amount are provided. From the above information, the calculation correction value of the correction value calculation unit 37 that calculates the correction value of the DC gain is input as a signal defining the amplification degree, and the output of the GCA 36 in which the amplification degree is defined by the calculation correction value is subtracted. Circuit 32
To correct the comparison output of the comparison circuit 30.

In this way, the frequency characteristic of the loop gain of the dimming circuit 16 is dynamically corrected to prevent the occurrence of hunting, and since the DC gain is not changed, the EE proportional to the set value of the reference signal REF. It becomes a signal, and the influence of the correction is not affected except the dynamic. Therefore, even when capturing an image, an appropriate captured image can be obtained by using this EE signal.

According to the present embodiment, the hunting does not occur even if the DC gain of the dimming circuit 16 is not changed and any diaphragm blade is combined with any video processor 4, etc., and the optimum response is obtained. It is possible to realize the automatic dimming function.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention.
Endoscope system 1 having light source device 3B of the embodiment
The structure of B is shown. The endoscope system 1B shown in FIG. 2 is different from the first embodiment in the configuration of the dynamic control loop portion.

That is, the output of the damper coil 34 has a plurality of low-pass filters (hereinafter,
41A, 41b, and 41c, which are abbreviated as LPF, and these outputs are input to the GCA 36 through the changeover switch 42. Further, as the changeover switch 42, the corresponding LPFs 41a, 41b, 41c are selected according to the output of the correction value calculation unit 37. Other configurations are the same as those in FIG.

In the present embodiment, the correction value calculation unit 3
LPF 41a having a frequency characteristic corresponding to the output of
By selecting 41b and 41c, it is possible to respond with a loop gain having an appropriate frequency characteristic. The present embodiment has almost the same effects as the first embodiment.

(Third Embodiment) FIG. 3 shows a third embodiment of the present invention.
Endoscope system 1 having light source device 3C of the embodiment
The structure of C is shown. The endoscope system 1C shown in FIG. 3 differs from the first embodiment in the configuration of the dynamic control loop portion.

That is, the output of the damper coil 34 is A / D.
After being converted into a digital signal by the converter 51, F
After passing through the LPF composed of the PGA 52, it is converted again into an analog signal by the D / A converter 53,
It is input to the GCA 36.

The FPGA 52 has a plurality of ROMs 54a,
The contents of 54b and 54c selected by the changeover switch 55 are written, and the LPF functions as an LPF having a cutoff frequency characteristic corresponding to the written contents.

The selection by the changeover switch 55 is determined according to the output signal of the correction value calculation unit 37. Other configurations are the same as those in FIG. In the present embodiment, the plurality of ROMs 54a, 54b,
54c is selected, and the contents of the selected ROM are written to the FPGA 52, so that the ROM
An LPF corresponding to the contents of is formed. The function of this LPF is the same as that of the second embodiment. In this embodiment, a single FPGA 52 can realize the functions of a plurality of LPFs having different frequency characteristics. Others have the same effects as described in the first embodiment.

[Additional Notes] 2. The first detecting means is a light quantity detecting means for detecting a light quantity I at each diaphragm position when sequentially moving from the fully open position by a constant movement amount, and a difference in light quantity between the current diaphragm position and the preceding diaphragm position. I (N-1) -I (N) is calculated and the ratio of the light amount I (N) at the current diaphragm position is calculated, and the ratio calculated by the calculation means is used to change the transmittance of the diaphragm unit at the current diaphragm position. The light source device according to claim 1, wherein the light source device is configured by a storage unit that stores the amount.

3. The second detecting means is a light amount detecting means for detecting the light amount at each aperture position when sequentially moving from the fully open position by a constant amount of movement, and a brightness signal EE output from the observation device at the current aperture position. (N) and the brightness signal EE (N-
1) difference EE (N-1) -EE (N) and the difference I (N-1) -I in the amount of light between the current diaphragm position and the preceding diaphragm position.
(N) is obtained and EE (N-1) -EE (N) and I (N-
1) -I (N) ratio calculating means, and the brightness signal of the observing device with respect to the change amount of the incident light quantity when the brightness signal EE (N) at the current diaphragm position is obtained by the calculating means. The light source device according to claim 1, wherein the light source device is configured to store as a variation amount of

4. The control means outputs a third detection means according to the opening / closing operation of the diaphragm means, an integrating means for integrating the output of the third detecting means, and an output of the integrating means with an amplification degree according to the control signal. 2. The GCA for performing the above operation, and the correction value calculation section for inputting the outputs of the first detecting means and the second detecting means and outputting a control signal for varying the amplification degree of the GCA according to each value. Light source device.

5. The control means selects a third detection means that outputs according to the opening / closing operation of the diaphragm means, a plurality of LPFs that integrate the output of the third detection means, and outputs of the plurality of LPFs according to the control signal. G for inputting the output of the switching means and the LPF selected by the switching means and amplifying the output with a specified amplification degree
The CA and a correction value calculation unit for inputting the outputs of the first detecting unit and the second detecting unit and outputting a control signal for controlling the input signal selection of the switching unit according to each value. Light source device.

6. The control means outputs a third detection means that outputs according to the opening / closing operation of the diaphragm means, a plurality of ROMs that store circuit information of a plurality of LPFs having different state functions, and outputs of the plurality of ROMs according to a control signal. Switching means to be selected by the switching means, an FPGA that constitutes an LPF that inputs the output of the ROM selected by the switching means, and integrates the output of the third detecting means with a state function according to the circuit information, and the third detecting means. The A / D converter that digitizes the output of the FPGA to the FPGA, the D / A converter that analogizes the output of the FPGA, and the GCA that amplifies the output of the D / A converter with a specified amplification degree, 2. A correction value computing section for inputting outputs of the detecting means and the second detecting means and outputting a control signal for controlling input signal selection of the switching means in accordance with each value.
The light source device according to claim 1.

[0070]

As described above, according to the present invention, the diaphragm means for increasing / decreasing the amount of emitted light and the diaphragm means for inputting the brightness signal of the object image output by the observation device for outputting the object image as an image signal are provided. In a light source device having a dimming circuit for controlling, first detection means for detecting a change amount of transmittance of a diaphragm means and second detection means for detecting a change amount of a brightness signal of an observation device with respect to a change in incident light amount. Means and a control means for controlling the response without changing the DC gain of the dimming circuit according to the outputs of the first detection means and the second detection means, so that even if the combination is different, it is optimal. A response speed can be set, and automatic light control can be performed in which the level of the EE signal is not affected by the correction value in terms of direct current and is proportional to the set value of the reference value.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an endoscope system having a light source device according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration of an endoscope system having a light source device according to a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a configuration of an endoscope system having a light source device according to a third embodiment of the present invention.

[Explanation of symbols]

 1A ... Endoscope system 2 ... Electronic endoscope 3A ... Light source device 4 ... Video processor 5 ... Monitor 6 ... Light guide 8 ... Lamp 9 ... Solid-state image sensor 10 ... Observation device 13 ... Video signal creation circuit 14 ... DC conversion circuit 16 ... Light control circuit 17a ... 1st calculation part 17b ... 2nd calculation part 18 ... Light receiving element 19 ... Aperture 22 ... Motor 24 ... Potentiometer 25 ... Comparison circuit 26 ... Counter circuit 27 ... Integration circuit 29a ... 1st memory 29b ... 2 memory 30 ... comparison circuit 31 ... host CPU 32 ... subtraction circuit 33 ... operation panel 34 ... damper coil 35 ... integration circuit 36 ... GCA

Claims (1)

[Claims] 1. A light source device comprising: a diaphragm means for increasing or decreasing the amount of emitted light; and a light control circuit for controlling a diaphragm means by inputting a brightness signal of a subject image output by an observation device for outputting a subject image as an image signal. A first detecting unit that detects a change amount of the transmittance of the diaphragm unit, a second detecting unit that detects a change amount of the brightness signal of the observation device with respect to a change of the incident light amount, a first detecting unit, and a second detecting unit. The light source device is provided with control means for controlling responsiveness without changing the DC gain of the dimming circuit according to the output of the detection means.