JPH0511287B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a light source device for an endoscope, and particularly to a light source device for an endoscope whose light amount is variable.

BACKGROUND ART Generally, in endoscopic diagnosis, a light source device is required because the inside of a body cavity is completely dark with no external light entering. Here, there are two types of diagnosis: one is to directly observe the inside of the body cavity using an endoscope, and the other is to take a photograph of an image obtained by the endoscope and make a diagnosis based on the photograph. Since the required amount of light differs between direct observation and photography, the light source device has a variable amount of light. Furthermore, since the appropriate amount of light varies depending on the target area, adjustment of the amount of light is essential. This light intensity adjustment can be done, for example, by switching lamps, changing the current supplied to the lamps,
This is done by driving the aperture. By the way, in conventional light source devices, it is difficult to know whether various functions including light amount adjustment operate normally until the device is actually used. Therefore, if the endoscope is used without knowing the abnormality (inserting the endoscope into a body cavity), it will cause unnecessary pain to the patient, and
Diagnosis may fail. In order to solve this problem, a device for checking the operation of the diaphragm in advance is described in Japanese Patent Laid-Open No. 86522/1983. This device checks whether the difference in the amount of light between the minimum aperture value and the maximum aperture value, that is, the dynamic range from the minimum aperture value to the maximum aperture value, is within a specified value range. However, during actual use, it was not known whether the aperture would actually be narrowed down to each aperture value between the minimum and maximum aperture values indicated by the aperture drive signal. In addition, the aperture was adjusted based on the drive angle of the aperture blades, but the amount of drive and actual drive angle of the aperture blades differ depending on the device, and the optical axis of the lamp and the center of the aperture blades are different from each other. Because of the difference, it was impossible to accurately adjust the amount of light. To solve this problem, a device that monitors the amount of light emitted from the lamp and controls it so that the value remains constant is disclosed in Japanese Patent Laid-Open No. 58-94829 and Japanese Patent Laid-Open No. 58-94829.
It is described in the -87526 publication. In these devices, so-called feedback control is performed when the lamp is actually used, but an appropriate amount of light emission may not be obtained due to a delay in control. Furthermore, in the former case, the CPU is required to constantly perform control operations, and there is a problem that the CPU cannot perform other processing.
Furthermore, in the latter case, it is necessary to provide a dedicated control circuit, which has the disadvantage of complicating the configuration.

Purpose The purpose of this invention is to determine the relationship between the aperture value and the amount of light in advance, memorize it, and then control the aperture based on the memorized relationship during actual use to obtain an accurate amount of light. An object of the present invention is to provide an endoscope light source device that can be controlled.

Overview This purpose is to provide an aperture means having multiple aperture values for adjusting the amount of light, a means for detecting the amount of light incident on the light guide via the aperture means, and a means to adjust the aperture means to each aperture value before using the light source device. means for storing the amount of light detected by the detection means when set to , together with the aperture value;
A light source device for an endoscope that illuminates the inside of a body cavity via a light guide, comprising means for controlling an aperture means when the light source device is used based on the relationship between the detected light amount and the aperture value stored in the storage means. This is realized by

According to the endoscope light source device according to the present invention, the amount of light at each aperture value is detected in advance, the relationship between the aperture value and the detected amount of light is stored in a memory, and the relationship between the aperture value and the detected amount of light is stored in memory. Based on this, select an appropriate aperture value according to the amount of light you want to introduce into the endoscope, and control the aperture accordingly.
Even if the correspondence between the drive amount of the aperture mechanism and the actual aperture value is not in a predetermined relationship, the aperture value that provides the desired amount of light can be determined, so the amount of light can always be controlled correctly.

Embodiment Hereinafter, an embodiment of the light source device for an endoscope according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a main part showing the structure, and FIG. 2 is a sectional view taken from the - line in FIG. 1. Although the light source for an endoscope is sometimes built into the tip (objective part) of the endoscope, an example will be described here as an external light source device connected to a light guide. In this embodiment device, a socket 2 is provided in a part of the front panel 1, and a connector 3 provided at the extending end of a light guide cord of the endoscope main body (not shown) is detachably connected to this socket. . Although not shown on the front panel 1, there is a display section for displaying check results. The light guide tube 4 of the connector 3 is located on the optical axis L of the light source lamp 5, and the light condensed through the condenser lens 6 is incident on its entrance end surface 4a. The condensing lens 6 is supported by a lens support frame 7. A turret 8 is provided between the light source lamp 5 and the condensing lens 6, the periphery of which is provided with a plurality of color filters 9 having different color characteristics (transmission characteristics) and a simple window (through hole). The turret 8 is rotationally driven by a drive motor 12, and either the color filter 9 or the window is selectively positioned on the optical axis L of the light source lamp 5. A gear mechanism such as a bevel gear 13 is used to transmit rotation from the drive motor 12 to the turret 9.

As shown in FIG. 2, the support plate 14 of the socket 2 is provided with shutter blades 15 used for photographic shutter operation and aperture blades 16 used for adjusting the amount of light so as to sandwich the optical axis L from both sides. . The shutter blade 15 and the aperture blade 16 are driven by motors 17 and 18, respectively. The shutter blade 15 selectively blocks or opens the optical axis of the lamp 5 to perform a shutter operation for photographing. Both ends of the rotation range of the shutter blade 15 are dampers 19,
It is regulated by 19. The diaphragm blades 16 have cuts that change the amount of blocking of the optical axis of the lamp as the rotation angle changes. As shown in FIG. 1, the aperture blades 16 are provided closer to the light source lamp 5 than the shutter blades 15 are. Therefore, the shutter blades 15 are designed to block the light modulated by the aperture blades 16. Further, a portion 21 of the shutter blade 15 located on the optical axis L of the light source lamp 5
is a reflective surface and is bent.
Therefore, the shutter blade 1 is
The optical path of the light incident on 5 is changed by 90 degrees and directed downward. The reflective surface 21 is treated with a matte finish to make the reflected light diffused light. The reflected light from the reflective surface 21 is incident on the light receiving element 23. The light receiving element 23 is
It is installed in a light-shielding box 22 for removing unnecessary leaked light. The light-shielding box 22 has a small hole 24 on its upper wall surface.
, so that only the light that has passed through this small hole 24 is incident on the light receiving element 23 .

FIG. 3 is a block diagram showing the entire control circuit of this embodiment. via system bus 36
A CPU 30, ROM 32, RAM 34, and interface (I/F) circuit 38 are connected.
The RAM 34 stores an aperture table, which will be described later. A turret drive circuit 40 is connected to the I/F circuit 38.
A motor 12 for driving the turret 8 via
is connected, and a motor 17 for driving the shutter blade 15 is connected via a shutter drive circuit 42. The light source lamp 5 is controlled by the I/F circuit 38 via the light source control circuit 44. Light receiving element 23
The anode of the photodiode as an electrode +V
, and its cathode is grounded via a resistor 46. The connection point between the photodiode 23 and the resistor 46 is connected to a first input terminal of an AND gate 52 via an amplifier circuit 48 and a voltage/frequency (V/F) converter 50. At the second input terminal of the AND gate 52,
A signal from the I/F circuit 38 is input. AND
The output signal of the gate 52 is supplied to the counter 54, and the output signal of the counter 54 is supplied to the I/F circuit 38. On the other hand, the output signal of the I/F circuit 38 is input to the variable frequency oscillator 56, and the output signal is supplied to the first input terminal (+) of the mixer 60 via the frequency/voltage (F/V) converter 58. Ru. The output signal of the mixer 60 is supplied as a drive signal to the motor 18 for driving the aperture blades 16 via an amplifier 62. The amount of rotation of the motor 18 is detected as a voltage signal by the potentiometer 64, and is non-feedback to the second input terminal (-) of the mixer 60. I/F
Also connected to the circuit 38 is a camera 66 that is connected to the eyepiece of the endoscope. In this example, this means:
This is to check that data is sometimes sent and received between the light source and the camera.

Next, the operation of this embodiment will be explained with reference to the operation flowchart of the CPU 30 shown in FIG. When a check button (not shown) is pressed, the operation is started, and as shown in step 100, the shutter blade 15 is closed and the optical axis of the lamp 5 is shielded from light. It is preferable to press this check button before using the light source device, but it may be pressed at any time during use. The shutter blade 15 is closed when
As shown in FIG. 1, this is to allow light to enter the light receiving element 23 and to prevent the light guide tube 4 from burning. In step 105, in order to increase the amount of light to the light receiving element 23, the turret 8 is rotated so that the empty filter is on the optical axis L of the light source lamp 5. Taking into account the mechanical delay in the rotation of the turret 8, as shown in step 110,
A waiting process for a predetermined time (3 seconds) is executed.
Thereafter, as shown in step 115, the light source lamp 5 emits light with a predetermined amount of light. This light emission is only for checking whether the light source lamp 5 is lit.
The amount of light emitted may be small. The light emitted from the light source lamp 5 is reflected by the reflective surface 21 of the shutter blade 15 and input to the light receiving element 23, and the V/F converter 50 obtains a signal (pulse signal) with a frequency corresponding to the amount of light. After this, the AND gate 52
Due to the gate signal of a certain period output from 8,
The output pulse signal of the V/F converter 50 is turned on for a certain period of time, and the output pulse signal of the V/F converter 50 is passed to the counter 54 for this certain period.
is input. That is, the counter 54 counts the output pulse signals of the V/F converter 50 during this fixed period, as shown in step 120. In other words, the counter 54 detects the amount of light emitted from the light source lamp 5 as the number of pulses N1. As a result, as shown in step 125, the detected value N1 and the reference value Nth1 are
(Theoretical value when the lamp emits light with a predetermined amount of light) is compared to determine whether the lamp is lit normally and whether the shutter blade 15 is properly closed. Detection value N1 is reference value Nth1
If it is below, at least one of these two is abnormal, and as shown in step 130, the occurrence of the abnormal condition is displayed on the display section (not shown) on the front panel.

When the detected value N1 is greater than or equal to the reference value Nth1, it is determined that these two items are normal, and the next check (lamp flash light emission check) is started.
As shown in step 135, the light source lamp 5 emits flash light at a light intensity (large light intensity) during photographing. Here, the current to the light source lamp 5 is increased to cause flash light emission, but the lamp itself may be switched. Similarly to the lighting check, as shown in step 140, the V/
The number of output pulses from the F converter 50 is counted by a counter 54. At step 145, the count value N2 at this time is compared with a reference value Nth2 (theoretical value when the lamp flashes). If the count value N2 is less than the reference value Nth2, this means that the flash light emission has not been performed correctly, so as shown in step 150, the occurrence of this abnormal state is displayed. When the count value N2 is equal to or greater than the reference value Nth2, it can be seen that the flash light emission is also normal.

In this embodiment, the amount of light is controlled based on the rotational drive angle of the aperture blades 16, so next,
The operation of the aperture blades 16 (the relationship between the aperture value and the actual amount of light) is checked. This is because the amount of light that actually enters the light guide may differ from device to device even if the rotational drive angle of the aperture blades is the same due to misalignment of the optical axis or variations in the amount of light from the lamp itself. First, as shown in step 155, the aperture is set to maximum (open). Aperture control is
This is done by the CPU 30 controlling the oscillation frequency of the variable frequency oscillator 56. The oscillation frequency of the variable frequency oscillator 56 is converted into a driving voltage signal for the motor 18 by the F/V converter 58, and the motor 18 is rotated. Since the amount of rotation of the motor 18 is negatively fed back to the drive voltage signal of the motor 18 via the potentiometer 64, the aperture blades stop at a predetermined position corresponding to the oscillation frequency of the variable frequency oscillator 56. In step 160, the counter 54 calculates the amount of light received by the light receiving element 23 at this time as the number n1 of output pulses from the V/F converter 50 within a certain period. In step 165, the aperture value (rotation angle of the aperture blades) and the amount of light received by the light receiving element 23 n1 (counter value) are associated and stored as an aperture table. This storage operation (creation of an aperture table) is performed for all apertures up to the minimum aperture, as shown in steps 170 and 175. As shown by the solid line in FIG. 5, in the aperture table, values other than the actual measured values are determined by interpolation, and are stored in the RAM 34 in the form of a characteristic curve of the drive angle of the aperture blades and the amount of light. From this characteristic curve, the driving angle of the diaphragm blades at which the desired amount of light can be obtained is calculated backwards. That is, when the light source device is actually used from now on, the drive angle of the aperture blades is controlled based on the aperture table stored in the RAM 34. The dashed curve in FIG. 5 shows the characteristics in an ideal case. When the amount of light received by the light receiving element 23 at the minimum aperture value ni is determined, as shown in step 180,
As the aperture is narrowed down, it is determined whether the amount of light received by the light receiving element 23 has decreased. If the amount of light received by the light-receiving element 23 does not decrease as the aperture is narrowed down, an error message will be displayed as shown in step 185, indicating that the aperture blades 16 are not being driven normally, and the amount of light received will decrease. If so, the operation of the aperture blades 16 is determined to be normal.

Next, in order to check data transmission/reception operations with the camera 66, a predetermined transmission request is issued to the camera 66, as shown in step 190. In step 195,
It is determined whether the camera 66 has transmitted any data in response to this transmission request. step
If no data is received from the camera in step 195, an abnormality is displayed as shown in step 200.

When data from the camera is received, it is checked that all functions are normal, and preparations for normal operation begin. That is,
As shown in step 205, the turret 8 is rotated so that a predetermined filter is positioned on the optical axis L of the light source lamp 5. As shown in step 210,
After waiting for a time corresponding to the delay time of driving the turret 8, the shutter blade 16 is opened as shown in step 215 (the light source lamp 5
optical axis L is opened). After this, step 220
will display that all check results are normal.

In the above explanation, five functions are checked: lamp lighting, lamp flash, shutter blade operation, aperture blade operation, and data exchange with the camera, and the correspondence between the aperture blade drive angle and the aperture light amount is checked. Since the relationship is confirmed, accurate light amount adjustment can be achieved. Note that it is not necessary to perform all five checks.

Effects of the Invention As explained above, according to the present invention, the relationship between the aperture and the amount of light is determined in advance, and the relationship is memorized.
Provided is a light source device for an endoscope that can accurately control the amount of light by determining the aperture so that a desired amount of light can be obtained based on the stored relationship during actual use.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing the configuration of an embodiment of an endoscope light source device according to the present invention, and FIG.
3 is a block diagram of the control circuit of this embodiment, FIG. 4 is a flow chart showing the operation of this embodiment, and FIG. 5 is a sectional view taken from the - line in the figure. This is a characteristic curve created during operation that shows the relationship between the driving angle of the aperture blades and the actual amount of light. 5... Light source lamp, 8... Turret, 15...
... Shutter blade, 16 ... Aperture blade, 23 ... Light receiving element, 30 ... CPU, 38 ... Interface circuit, 50 ... Voltage/frequency conversion circuit, 54
...Counter, 66...Camera.

Claims (1)

[Claims] 1. In an endoscope light source device that illuminates the inside of a body cavity through a light guide, an aperture means having a plurality of aperture values for adjusting the amount of light, and means for detecting the amount of light incident on the light guide via the aperture means. and,
means for storing the amount of light detected by the detection means together with the aperture value when the aperture means is set to each aperture value before using the light source device; and the amount of light detected and the aperture value stored in the storage means when the light source device is used; and means for controlling the aperture means by determining an aperture value of the aperture means such that the amount of light incident on the light guide becomes a desired value based on the relationship between the aperture value and the aperture value.