JP3134997B2 - Light source device for endoscope - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endoscope light source device that supplies illumination light to an endoscope.

[Conventional technology]

Many endoscope light source devices incorporate an automatic light control device for automatically controlling the amount of illumination light supplied to the endoscope. When such an endoscope light source device with an automatic light control device is used, the amount of illumination light supplied to the endoscope is automatically controlled to an optimal state according to the distance to the subject.

[Problems to be solved by the invention]

However, if the endoscope is left unused without being connected to the light source device, in the conventional light source device for an endoscope as described above, the amount of illumination light supplied to the endoscope is often reduced. Is at its maximum.

This not only wastes power, but also causes the connection of the endoscope to the light source device (generally, the protruding end of the light guide connector) to become extremely hot, causing an unexpected burn when removed from the light source device. There was a risk of causing an accident.

An object of the present invention is to provide a light source device for an endoscope which solves the conventional drawbacks and cuts off the supply of unnecessary illumination light when the endoscope is not used, thereby improving safety and economy. Aim.

[Means for solving the problem]

In order to achieve the above object, a light source device for an endoscope according to the present invention includes a light source that supplies illumination light for illuminating a subject to an endoscope, and a luminance of the subject illuminated by the illumination light. A luminance change detecting means for detecting a change, and a detection signal from the luminance change detecting means, which is supplied from the light source to the endoscope when the luminance of the subject has not changed for a predetermined time. An illumination light amount control means for reducing the illumination light amount is provided.

In addition, an automatic dimming unit that controls the amount of illumination light supplied from the light source to the endoscope so as to stabilize the brightness of the subject is provided, and the amount of illumination light supplied from the light source to the endoscope is provided. From the change, the luminance change detecting means may detect a change in the luminance of the subject.

[Action]

When the luminance of the subject has not changed for a predetermined time, the endoscope is not used, and the amount of illumination light supplied from the light source device to the endoscope automatically decreases.

〔Example〕

 Embodiments will be described with reference to the drawings.

In FIG. 1, 1 is an endoscope. Reference numeral 2 denotes a light source device that supplies illumination for illuminating the subject 100 to the endoscope 1.

A light guide connector 18 having an incident end 11a of a light guide fiber bundle 11 for illumination of the endoscope 1 is detachably inserted into the light source device 2, and a light source is inserted into the light guide fiber bundle incident end 11a. The illumination light generated from 21 is condensed and incident.

The illuminating light is transmitted by the light guide fiber bundle 11 and illuminates the subject 100 from the distal end 12 of the insertion section of the endoscope. The light reflected by the subject 100 is transmitted by the image guide fiber bundle 13, and the photoelectric conversion element
Irradiated at 14. As a result, the luminance of the subject 100 is converted by the photoelectric conversion element 14 into an electric signal (luminance signal).

Note that a general light receiving element can be used as the photoelectric conversion element 14, but a solid-state imaging element may be used instead of the image guide fiber bundle 13, and in this case, the solid-state imaging element is It becomes 14.

21a is a light source power supply circuit. Reference numeral 23 denotes a stop arranged in an illumination light path between the light source 21 and the light guide fiber bundle incidence end 11a.The amount of illumination light supplied to the light guide fiber bundle 11 is changed by changing the brightness of the light source 21 itself. Alternatively, it can be performed by controlling the opening degree of the throttle 23.

Reference numeral 30 denotes a control unit for controlling the operation of the light source device 2. The control unit 30 receives a luminance signal from the photoelectric conversion element 14, and outputs a control signal to the light source power supply circuit 21a and the drive circuit 23a of the aperture 23. Further, a dimming method selection switch 25 for selecting whether the dimming method of the lighting is manual or automatic and a brightness level setting switch 26 for setting the luminance level of the subject are provided on the front panel of the light source device 2. And each is connected to the control unit 30.

FIG. 2 is a block diagram showing a circuit configuration of the control unit 30, and includes a system bus 3 connected to a central processing unit (CPU) 31.
2, a RAM 33, a ROM 34, and the like are connected. The dimming mode selection switch 25 and the brightness level setting switch 26 are connected to a system bus 32 via a first input / output port 35. At the output end of the second input / output port 36, a light source current control circuit 37 for controlling the current of the light source 21 and the aperture 23
An aperture control circuit 38 for controlling the opening and closing operation of the aperture is connected.

The luminance signal from the photoelectric conversion element 14 is input to the photometric circuit 41. A sampling pulse is input to the photometry circuit 41 from a timer 42 connected to the system bus 32 via a sampling circuit 43, and the luminance signal is integrated by the photometry circuit 41 while the sampling pulse is at a low level. Output to the circuit 44.

Then, the peak value of the integrated output value is held by the sample / hold circuit 44, and the analog / digital conversion circuit
The signal is converted into a digital signal at 45 and sent to the system bus 32.

FIG. 3 is a time chart showing the operation of the above embodiment. As described above, the photometry circuit 41 has a sampling circuit.
When the sampling pulse input from 43 is at the low level, the luminance signal is integrated by the photometry circuit 41, and when the sampling pulse is at the high level, the integrated output returns to zero. Therefore, a saw-tooth signal is output from the photometry circuit 41, and each peak value is held by the sample and hold circuit 44 and processed by the CPU 31.

When the dimming mode selection switch 25 is set to automatic dimming, the amount of light supplied to the endoscope is reduced if the luminance signal is larger than the set value, and if the luminance signal is smaller than the set value, the amount of light supplied to the endoscope is reduced. The amount of light supplied to the mirror is increased, and the light is automatically adjusted so as to keep the brightness of the subject constant. The set value of the luminance signal is set by operating the brightness level setting switch 26.

Also, regardless of the state of the dimming method selection switch 25, that is, in either the automatic dimming state or the manual dimming state, the magnitude of the luminance signal does not change for a certain period of time T ₁ (for example, two minutes). When there is no change in the integrated output value from the photometric circuit 41, it is determined that the endoscope 1 is in a non-use state, and the amount of illumination light supplied to the endoscope 1 is automatically reduced to the lowest level, and Light state.

However, the magnitude of the luminance signal changes,
If there is a change in the integrated output value from 41, the illumination light amount supplied to the endoscope 1 is automatically returned to the normal state.

FIG. 4 is a flowchart of a control process performed by the control unit 30 to perform the above operation. s indicates a step.

This process starts, for example, when the power of the light source device 2 is turned on. When the brightness of the subject is first input in s1, it is determined in s2 whether or not the illumination is in a dimmed state. The state of the optical system selection switch 25 is determined.

Then, when in the automatic light control state, after performing the automatic light control operation in s4, proceed to s5, and when not in the automatic light control state,
Proceed directly from s3 to s5.

In s5, it is determined whether or not the subject brightness has not changed from the input value just before the processing loop. Then, when there is no change in the luminance, 1 is added to the counter for the time count at s6.
It was added to determine if at s7, or the value of the counter has reached the constant C _1. The C ₁ is a constant corresponding to the predetermined time T _1. Note that the initial value of the counter is 0.

In s7, when the value of the counter has not reached the constant C _1, i.e., when no elapsed time T ₁ is repeated back to s1 again. However, in s7, when the value of the counter has reached a constant C _1, namely, when the elapsed time T ₁ is a s8, and the illumination light supplied to the endoscope 1 to the dimming state, returns to s1.

When the subject brightness changes in s5, s9
Then, return the counter to 0 and return to s1.

Also, in s2, when the illumination is in the dimmed state, s10
Then, it is determined in the same manner as in s5 whether or not there is a change in the brightness of the subject.If there is no change in the brightness, the process returns to s1. At the same time as returning the amount of illumination light supplied to the mirror 1 to a normal state, the content of the counter is returned to 0 and then to s1.

In the above-described flowchart, the luminance of the object is controlled by inputting the luminance of the subject for each round of the processing loop. However, it is not always necessary to determine whether the luminance of the subject has changed every round of the loop. Instead, it may be performed once in several loops, for example, once every 0.1 second.

The reason is that, for one, the time during which the subject luminance does not change is long, for example, two minutes, and thus it is not necessary to make a determination at a short interval of once per processing loop. For one thing, the sampling pulse is about 500 Hz, for example, so once input subject brightness is the same for about 0.002 seconds, whereas the processing time around one processing loop is usually less than 0.002 seconds. is there.

FIG. 5 shows a circuit configuration of a second embodiment of the present invention. The overall configuration of this embodiment is the same as FIG. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

In this embodiment, as shown in FIG. 5, the output from the sample-and-hold circuit 44 is input to the aperture control circuit 38, and the aperture control is performed via the analog-digital conversion circuit 45 and the digital-analog conversion circuit 46. Signals are exchanged between the circuit 38 and the system bus 32.

FIG. 6 shows an example of the circuit configuration of the aperture control circuit 38 of the second embodiment.

Here, a throttle opening detector 38 that detects the opening of the throttle 23
The detection signal from a is sent to the CPU 31 through the aperture setting unit 38b, and the sample and hold circuit 44
Is added to the output signal from

The changeover switch 38d is switched by the input of a high-level or low-level switch signal from the CPU 31, and the comparator 38e
Is switched to the output from the sample and hold circuit 44 (ie, during normal automatic dimming) or the output from the adder 38c (ie, during dimming).

In the comparator 38e, the other comparison signal is input from the brightness level setting unit 26, and a high-level or low-level signal of the comparison result is output to the aperture driving circuit 23a, and the aperture of the aperture 23 is determined. Control. In this manner, the input of the high-level or low-level switching signal from the CPU 31
The opening degree of the diaphragm 23 can be switched between a normal automatic dimming state and a dimming state.

FIG. 7 is a time chart showing the operation of the second embodiment. In this embodiment, when the light source device 2 is performing automatic light control so as to always keep the subject brightness constant, when the state of the diaphragm 23 has not changed for a certain period of time, that is, the endoscope 1 When there is no change in the supplied illumination light amount for a certain period of time, the CPU 31 outputs a low-level signal to the aperture control circuit 38 to narrow the aperture of the aperture 23 and supply the same to the endoscope 1. To reduce the amount of illumination.

When the opening degree of the diaphragm 23 changes, that is, when the amount of illumination light supplied to the endoscope 1 changes, the CPU 31 outputs a high-level signal to the diaphragm control circuit 38, and
To the normal automatic dimming state.

That is, in this embodiment, on the assumption that the automatic light adjustment is performed, the change in the subject brightness is detected by the change in the illumination light amount (the change in the opening degree of the diaphragm 23).

FIG. 8 is a flowchart of a control process according to the second embodiment. s indicates a step.

In this case, first in s21, the dimming method selection switch 25
Is determined, and when the automatic light control is not performed, the determination of s21 is repeated. At the time of automatic light control, the aperture opening (that is, the amount of illumination light supplied to the endoscope 1) is input in s22, and s23
It is determined whether or not the light is in the dimmed state.

Then, when not in the dimming state, that is, in the normal automatic dimming state, in s24, for example, when there is no change in the diaphragm opening compared to the diaphragm opening in the immediately preceding processing loop, that is, when the illumination when there is no change in light amount, it adds 1 to the counter for time counting in s25, determines whether at s26, if the value of the counter has reached the constant C _1. The C ₁ is a constant corresponding to the predetermined time T _1.

In s26, when the value of the counter has not reached the constant C _1,
That is, when no time reaches T ₁ is repeated again returns to s21. However, at s26, the value of the counter is constant C ₁
When reached, i.e., when the time has T ₁ elapses, s27
Then, the aperture is reduced, the illumination light supplied to the endoscope 1 is reduced, and the process returns to s21.

When there is a change in the aperture opening in s24, that is, when there is a change in the amount of illumination supplied to the endoscope 1, s2
At 8 the counter is reset to 0 and the process returns to s21.

When the lighting is in the dimming state in s23, in s29,
It is determined whether there is a change in the aperture opening, that is, whether there is a change in the amount of illumination light supplied to the endoscope 1. When there is no change, the process returns to s21. When there is a change, in s30,
The dimming state is released to return to the normal dimming state. At the same time, the content of the counter is set to 0, and the process returns to s21.

As described above, in each of the above embodiments, the amount of illumination light supplied to the endoscope 1 may be reduced by reducing the light source current and making the brightness of the light source 21 darker. Can save power consumption.

〔The invention's effect〕

According to the endoscope light source device of the present invention, when the endoscope is not used, the amount of illumination light supplied from the light source device to the endoscope is automatically set even when the device is in use. Because of the decrease, the connecting portion of the endoscope to the light source device is not unnecessarily heated, and an accidental burn accident or the like can be prevented. In addition, even when the endoscope is in the body cavity, when there is a risk that the mucous membrane surface may be burned by the emitted light while being left facing the same subject,
The amount of illumination is reduced, so that an unexpected burn accident can be prevented. If the amount of illumination is reduced by reducing the light source current, a power saving effect can also be obtained.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of the first embodiment, FIG. 2 is a circuit block diagram of the first embodiment, FIG. 3 is a time chart showing the operation of the first embodiment, FIG. FIG. 5 is a control processing flowchart of the first embodiment, FIG. 5 is a circuit block diagram of the second embodiment, FIG. 6 is a circuit block diagram of the second embodiment, and FIG. FIG. 8 is a time chart showing the operation of the second embodiment, and FIG. 8 is a control processing flowchart of the second embodiment. DESCRIPTION OF SYMBOLS 1 ... Endoscope, 2 ... Light source device, 11 ... Light guide fiber bundle, 14 ... Photoelectric conversion element, 21 ... Light source, 23
…… Aperture, 30 …… Control unit.

Continuation of the front page (56) References JP-A-61-62438 (JP, A) JP-A-60-135728 (JP, A) JP-A-1-316684 (JP, A) Real opening 63-79096 (JP, A) , U)

Claims (3)

(57) [Claims] A light source for supplying illumination light for illuminating a subject to an endoscope; a luminance change detecting means for detecting a change in luminance of the object illuminated by the illumination light; The illumination light amount supplied to the endoscope from is controlled according to the detection result by the brightness change detection means,
An illumination light amount control means for reducing the illumination light amount when the brightness of the subject has not changed for a predetermined time. 2. The method according to claim 1, wherein said luminance change detecting means detects the presence or absence of a luminance change of said subject at a time interval shorter than said predetermined time. The light source device for an endoscope according to claim 1, wherein the control means reduces the illumination light amount. 3. An automatic dimming means for controlling the amount of illumination light supplied from the light source to the endoscope so as to stabilize the brightness of the subject, wherein the light source supplies the endoscope with light. The light source device for an endoscope according to claim 1 or 2, wherein the luminance change detecting means detects a change in luminance of the subject from a change in the amount of illumination light to be performed.