JPH0373845B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an endoscope light source device, and particularly to an endoscope light source device that can adjust the brightness of observation light.

An endoscope light source device is generally configured to generate observation light and photographing light, and the brightness of the observation light can be changed arbitrarily.
With conventional endoscope light source devices, the observation light may not reach the set brightness due to power supply voltage fluctuations, lamp variations, misalignment, or lamp deterioration due to long-term use, resulting in insufficient or excessive illumination of the subject, or flickering during observation. This may cause inconvenience to the user during endoscopic observation.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an endoscope light source device that can consistently obtain observation light of a set brightness.

Embodiments of the present invention will be described below with reference to the drawings. According to FIG. 1, an endoscope 1, a light source device (light source unit) 2, and an endoscope camera 3 constitute an endoscope photographing system. As shown in Figure 2,
The endoscope 1 is provided with an image guide 5 and a light guide 6, and a subject 4 is illuminated by light guided through the light guide 6. An objective lens 7 is provided at the front end of the image guide 5, and an eyepiece lens 8 is provided at the rear end. Camera 3 on eyepiece 9
is attached, and the beam splitter 10 of the camera 3 faces the eyepiece 8. Beam splitter 10
A film 11 is placed opposite to the mirror shutter 12 with a mirror shutter 12 interposed therebetween. The camera control circuit 13 includes a light receiving element 1 provided on the side surface of the beam splitter 10.
4 and the release switch 15. A signal end of the camera control circuit 13 is connected to a connection terminal group 16. The light source unit 2 is provided with a xenon (Xe) discharge lamp 18, and the connector portion 20 is connected to the light source unit 2 so that the light guide end 19 is located on the optical axis of the lamp 18. The connection terminal group 21 of the connector section 20 is connected to the light source control unit 17 via the socket of the light source unit 2. The Xe discharge lamp 13 has cathodes 22 facing each other.
, an anode 23, and a reflecting surface 24. A condenser lens 25, a shutter blade 26, and an aperture blade 28 are sequentially arranged between the Xe discharge lamp 13 and the light guide end 19. Shutter blade 26
is driven by a shutter solenoid 27, and the aperture blades 28 are driven by an aperture motor 29.
A light guide member 31 made of, for example, an acrylic rod is disposed between the light guide end 19 and the aperture blade 28. The tip of this light guide member 31 is the lamp 1
It has a slope on the third side, and a light receiving element 32 is disposed at the rear end. In FIG. 3, the shutter blade 26, the aperture blade 28, the light guide member 31, etc. are shown in perspective.

FIG. 4 shows the circuit configuration of the camera control circuit 13. According to this circuit, the light receiving element 14 is connected to an operational amplifier 36 of an integrator/current/voltage converter 37. An integral capacitor 34 and a current-voltage conversion resistor 35 are connected in series between the inverting input terminal and the output terminal of the operational amplifier 36. Short-circuit analog switches 38 and 39 are connected to the integral capacitor 38 and the resistor 35, respectively. The output terminal of the integrator and current-voltage converter 37 is connected to the operational amplifier 4 of the comparator 40.
It is connected to the non-inverting input terminal of 1. operational amplifier 41
The inverting input terminal of
It is connected to the chip CPU 33. operational amplifier 41
The output terminal of is connected to the non-inverting input terminal of an operational amplifier 47 of the buffer circuit 43 via an analog switch 44. Further, the non-inverting input terminal of this operational amplifier 47 is connected to the output terminal of the operational amplifier 36 via an analog switch 45. analog switch 4
Analog switches 4 and 45 are opened and closed by the output signal of the CPU 33, and are controlled by a signal via an inverter gate 46. The inverting input terminal of the operational amplifier 47 is grounded via a resistor 48 and connected to an output terminal via a resistor 49. The output end of this buffer circuit 43 is connected to terminal e. Terminal f is grounded, terminals a and b are connected to V
Connected to cc and GND respectively. Terminals e and d are connected to the CPU 3 via the serial interface 50.
Connected to 3. The CPU 33 is an inverter 51,
It is connected to Vc.c. via a light emitting diode (LED) 52 and a resistor 53.

FIG. 5 shows the light source control circuit 1 of the light source unit 2.
7 circuit configurations are shown. In this circuit, terminals e and d are serial interface 5
Connected to 4. serial interface 54
is the CPU55, ROM56, RAM5 via the bus.
7, A/D converter 58, D/A converter 5
9, connected to a condition setting/display unit 60 and a parallel interface 61; Terminal e is connected to non-inverting input terminals of operational amplifiers 64 and 67 of low amplification amplifier circuit 62 and high amplification amplifier circuit 63. The inverting input terminal of the operational amplifier 64 is grounded via a resistor 65 and connected to the output terminal via a feedback resistor 66. Similarly, resistors 68 and 69 are connected to the inverting input terminal of operational amplifier 67. The output terminal of the amplifier circuit 62 is connected to the non-inverting input terminal of the comparator 70. The output terminal of comparator 70 is connected to parallel interface 61. A current-voltage converter 75 to which the light receiving element 32 is connected is composed of an operational amplifier 76 and a resistor 77.
The output end of the D/A converter 59 is the aperture driver 7
It is connected to the inverting input terminal of the operational amplifier 79 of No. 8, and also connected to the emitter of the transistor 82 and the aperture motor 29 via a resistor 80. The collector of the transistor 82 is connected to V _s through the resistor 81, and the base is connected to the output terminal of the operational amplifier 79.

As shown in FIG.
It consists of an array of light emitting diodes (LEDs) and is designed to display a bar graph. The anode of the display 137 is connected to the power supply Vc.c. through a resistor, and the cathode is connected to port PC of the peripheral programmable interface (PPI) 144 of the conditioning and display unit 60 through an amplification. Bright switch 138, dark switch 139, steel A-M changeover switch 142 and cine A-M
A changeover switch 143 is connected to port PB of PPI 144. In addition, the steel ASA setting switch 140 and the cine ASA setting switch 141 are set to PPI1.
Connected to port PA of 44.

FIG. 7 shows the power circuit of the light source unit 2. As shown in FIG. The Xe discharge lamp 18 is connected to a high voltage generation source consisting of a high voltage generation circuit 83 and a high voltage generation coil 84. This high voltage generation source is connected to a rectifier circuit 89 via an Xe lamp current control section composed of an Xe lamp current control circuit 85, a current detection resistor 86, and a current control transistor 87, and a chiyoke coil 90. The power supply terminal of this rectifier circuit 89 is connected to the secondary winding of transistor 88 . The flash capacitor 91 is connected to a rectifier circuit 93 via a resistor 92.

A power terminal of the rectifier circuit 93 is connected to a secondary winding of a transformer 94. The primary winding of the transformer 94 is connected to the AC power line via a triax 95. Triac 95 is connected to a capacitor charging voltage control circuit 96 which generates a control signal in response to the charging voltage of capacitor 91. Capacitor 91
One end of the transistor 97 is connected to the emitter of the transistor 97 and a transistor drive circuit 98 . The collector of the transistor 97 is connected to the cathode of the Xe lamp 18, and the base is connected to the drive circuit. power supply circuit 99
is connected to the AC line via a transformer 100.

In the circuit described above, the A/D converter 58 has a built-in multiplexer and can output an 8-bit digital signal.
ADC0808 from NS is used. This ADC0808
has 8 channels of analog inputs and 8 bits of digital output, but in the embodiment, 4 channels of analog inputs _A0 to _A3 are used. Input A ₀ ,
A ₁ and A ₃ are connected to the outputs of amplifier circuits 62, 63 and current-voltage converter 75, respectively. The serial interface 54 and the CPU 55 are made by Intel.
If you are using 8085, you are part of that family.
Connected to camera 3 as UART using 8251A. The ROM 56 is selected according to the program capacity, and if the capacity is 2K bytes, the family 2716 is used. Further, 2114 is used for the RAM 57. The D/A converter 59 is used to convert 8-bit digital data into analog data, and specifically uses a DAC 108 manufactured by NS. This has the advantage of being directly connected to the data bus of the CPU 55. Note that the analog output of this D/A converter 59 is a current output, so the aperture driver 78
is converted to voltage by Further, the A/D converter 58 is designed to treat the 8-bit resolution as 16 bits. The condition setting/display unit 60 controls shooting still film sensitivity, cine film (TV) sensitivity, still/cine correction during auto shooting, still auto/manual switching, cine auto/manual switching, and manual cine, that is, manual light intensity setting. I'm starting to be able to do it. The parallel interface 61 uses Intel's Family 8255A.

Next, the operation of the above-mentioned endoscope system will be explained.

As shown in FIG. 1, the connector 20 of the endoscope 1 is connected to the light source unit 2, and the power switch 145 is
When turned on, the Xe discharge lamp 18 lights up. The light from this discharge lamp 18 is transmitted to the light guide member 31
The light is detected by the light receiving element 32 via the light receiving element 32. The light receiving element 32 converts the light from the light source into an electric signal corresponding to the brightness, that is, a light receiving signal. The received light signal is amplified by the current-voltage converter 75 and converted into a voltage signal, and the A/
It is input to terminal _A3 of D converter 58. CPU
55 measures the brightness of the light source based on the digital light reception signal from the A/D converter 58. Also,
The CPU 55 checks whether the Xe discharge lamp 18 is lit at 100% brightness. In this state, the cine A-M changeover switch 143 is set to manual, and for example, when the dark switch 139 is pressed,
The up-down counter of the PPI 144 counts down and the count information is input to the CPU 55.
The CPU 55 sequentially turns off the LEDs of the brightness display 137 in accordance with the count information. The brightness display 137 is configured to display, for example, eight levels depending on the brightness. That is,
For practical purposes, the brightness ranges from 100% on to 0% off.
It is divided into 8 stages from 100% to 20% and displayed in 8 stages. When the dark switch 139 sets the brightness to, for example, 80%, the CPU 55 controls the aperture driver 78 while monitoring the light reception of the light receiving element 32 so that the brightness reaches the set value of 80%. The diaphragm driver 78 drives the diaphragm motor 29 in accordance with information from the CPU 55, and causes the diaphragm 28 to narrow down the light from the Xe discharge lamp 18 to a set brightness. When the brightness reaches the set value, the aperture 28 is maintained at that aperture position. At this time, the focused light source, that is, the observation light, is monitored by the CPU 55 via the light receiving element 32, and the aperture 2 is used to maintain the set brightness constant.
8 is servo controlled. Therefore, even if the light intensity of the discharge lamp 18 decreases due to voltage fluctuations, the endoscope 1
The brightness of the light incident on the light guide end 19 is always constant. Note that if the lamp 18 has been used for a long time and the light intensity of the lamp 18 has decreased, dimming can only be performed below the decreased light intensity, so even if you keep pressing the brightness switch 138 to increase the brightness, the brightness will not change The display 137 only displays the maximum light intensity of the deteriorated lamp 18, for example, 90% or 80% brightness. This display allows you to understand the necessity of lamp replacement.

Next, the photographing operation will be explained with reference to the time chart shown in FIG.

When the release switch 15 is closed, the light source diaphragm 28 begins to open, the signals at terminals e to f of the camera 3 become low level, and the light source shutter 26 begins to close, so that the light incident on the light guide end 19 is blocked. , the output of the integrator/current-voltage converter 37 becomes 0 value. After a predetermined period of time, the mirror shutter 12 of the camera 3 opens and the light source shutter 26 opens, allowing light to enter the light guide end 19 and pass through the integrator and current-voltage converter 3.
The output of 7 operates as an integrator and integrates the light reception signal corresponding to the reflected light from the object. Light source shutter 26
The Xe lamp 8 flashes when it is fully opened. When the calculated exposure value reaches the proper exposure value, a "STOP" signal is generated, the Xe lamp 18 stops emitting light, and after a certain period of time, the mirror shutter 12 closes and the photographing ends. Thereafter, the Xe lamp 18 is turned on for observation, the aperture 28 controls the observation light to the set brightness, and the observation state is resumed. In addition, Vref in exposure calculation is determined by the ASA settings on the camera.
Since the light source is also set to the same ASA, it is possible to calculate the exposure before shooting.

Another embodiment is shown in FIG. 9, in which a strobe lamp 101 and a halogen lamp 102 are used as light sources. In this case, the light receiving element 32 is arranged to receive the light from the halogen lamp 102 passing through the opening 106 provided at the center of the mirror 103. Furthermore, mirror 10
Reference numeral 3 serves as a back mirror that guides the light from the strobe lamp 101 to the light receiving element 32. but,
Since the strobe light is very strong, the back mirror does not have a very high reflectance, and for example, a precisely finished metal surface may be used. With such a configuration, the light guide end 1 is
9 can be measured. FIG. 10 shows perspectively the arrangement of the light guide end 19, the light receiving element 32, the halogen lamp 102, and the mirror 103. The mirror 103 is moved by an optical path switching solenoid 105.

FIG. 11 shows the signal processing circuit 17 of the light source unit 2 of FIG. In this circuit, a current-voltage converter 75 is provided after the light-receiving element 32, and its output is input to the _A3 channel of the A/D converter 58, and is passed through an amplifier for signal inversion and a resistor 109 to an integrator/sample hold. It is input to circuit 107. The output of the integrator/sample hold circuit 107 is output from the A/D converter 58.
Input to A ₂ channel. Analog switch 111 is used to reset the integrator, and analog switch 112 is used to sample and hold after integration. The integral constant is resistor 109 and capacitor 1
10. The counter 113 is a timer interface and is called PIC. this
PIC is 8253A in Intel's 8085 family
use. Clock CLK is supplied from the clock of CPU55, and “GATE” is supplied with ZERO-
A "CROSS" signal is supplied, and a "BRIGHT" signal is input to "OUT".

A power supply circuit is shown in FIG. 12, and according to this circuit, a lighting circuit for a strobe lamp 101 and a halogen lamp 102 is provided. Main capacitor 114 is connected to voltage doubler rectifier circuit 125 . The charging control circuit 126 is connected to the main capacitor 11
It controls the charging pressure of 4 to be constant, and generates a "CHARGE" signal when charging is completed. A triax 129 provided in series and a phase control circuit 128 for controlling the triax 129 are connected to the halogen lamp 102 .

In the above-mentioned apparatus, a pre-photographing exposure calculation is performed. In this case, for example, in the initial operation when the power switch 145 is turned on, the ASA sensitivity etc. are set, and if the sensitivity is greater than the set value, the integral capacitor 110 is reset,
If it is less than the specified value, a warning of insufficient light quantity will be issued.
When the integral capacitor 110 is reset, the halogen lamp 102 is turned on and the A/D converter 5
8 multiplexer _A3 . When the halogen lamp 102 is turned on to the maximum, data is read from the A/D converter 58. Based on this data, it is determined whether the total amount of light emitted by the halogen lamp 102 is within the specified light amount, and if "NO", a decrease in the amount of light from the halogen lamp is displayed. If the determination is "YES", the pre-shooting exposure calculation preprocessing ends. This pre-shooting exposure calculation process was published in 1981.
This is explained in detail in the ``Automatic Exposure Device for Endoscopic Photography System,'' filed on November 18th.

The light intensity adjustment of the halogen lamp 102 is done using PIC113.
This is done using the 8253A in mode 5. The timing of the phase angle is counted down from the "ZERO CROSS" signal, and when the count reaches 0, only one cycle of the clock is output to "OUT". As for the count amount, the number of clock cycles of the phase angle is loaded into the count register by the CPU 55 according to the set brightness.
Counting is performed when reset by the CPU 55, and is counted down by the clock. By doing this, the amount of light from the halogen lamp 102 is arbitrarily adjusted by the CPU 55 according to the set value. Since the light intensity of the halogen lamp 102 can be adjusted as described above, automatic light control is possible according to the set value. However, halogen lamp 10
2 is not suitable for cine photography because there is a large change in color temperature when the light amount is adjusted by electric current. Furthermore, since the halogen lamp itself does not have enough light intensity, it is not suitable for cinema. For manual light intensity settings, use a predetermined light intensity-phase angle (count value) table according to the set light intensity.
Loaded into the count register of PIC113. This allows the CPU 55 to arbitrarily change the amount of light from the halogen lamp 102.

Pre-shooting exposure calculations are performed in the same manner as in the previous application. However, Lsend is the amount of light sent out from the halogen lamp 102, and Lrcv is the amount of light sent out from the halogen lamp 102.
is the amount of light reflected from the subject. The minimum shooting limit for L・t is 100 minutes L・t. This indicates that the range that can be photographed has expanded, and the flash control range has become wider. When determining LsendLrcv using the halogen lamp 102, the light receiving elements 14 and 3
It is necessary that the spectral sensitivities of 2 match.

The still photographing operation operates according to the time chart shown in FIG. In this photographing operation, "FLASH" and "STOP" of the strobe lamp 101 are performed from the time of light emission to the stop by well-known DC control and commutation. Of course, when taking still photos, it is necessary to check that the exposure calculations are appropriate before taking the photo. Since the subject is inside the body cavity, the stomach and other parts move repeatedly, so even if there is a deviation due to movement between the time when the exposure is calculated before the photo is taken, it is only a small amount of time, so it is important to Distance movement is not possible. Therefore, the exposure is calculated while the film is being exposed in real time, rather than being controlled based on the exposure value calculated before shooting, so the film may be overexposed or underexposed. Never.

As explained above, according to the present invention, the observation light incident on the light guide is monitored by the light receiving element and maintained at a constant brightness level, so that lamp variations, misalignment, lamp deterioration, and voltage fluctuations can be avoided. Even if these occur, a constant amount of light can be stably obtained without being affected by them. Note that in the present invention, the output of the light receiving element that monitors the light incident on the light guide can also be used for pre-photography exposure calculation, but the pre-photography exposure calculation can be easily performed by the CPU when manually setting the observation light. In addition, the light receiving element that monitors the light incident on the light guide monitors the light guided by a light guide member such as acrylic resin, but the light guide fiber is used as the light guide member and the light receiver is placed at a distant position. The observation light may be monitored by an element. Furthermore, the brightness control is not limited to eight levels, but may be more finely controlled, for example, to 100 levels.

[Brief explanation of drawings]

FIG. 1 is a perspective view of an endoscope system using an endoscope light source device according to an embodiment of the present invention, and FIG.
Figure 3 is a perspective view of the aperture mechanism and shutter mechanism, Figure 4 is a circuit diagram of the camera, Figure 5 is a circuit diagram of the signal processing circuit of the light source unit, and Figure 6 is a diagram of the internal configuration of the endoscope system shown in the figure. The diagram shows the condition settings shown in Figure 5.
FIG. 7 is a circuit diagram of the display circuit, FIG. 7 is a circuit diagram of the power supply circuit, FIG. 8 is a time chart explaining the photographing operation, and FIG. 9 is a diagram of the internal structure using an endoscope light source device according to another embodiment. FIG. 10 is a schematic diagram of an endoscope system using an endoscope light source device of another embodiment. FIG. 11 is a signal processing circuit of the light source unit shown in FIG. 10. 12 is a circuit diagram of the power supply circuit of the light source unit used in FIG. 11, and FIG. 13 is a time chart showing the photographing operation according to the embodiment of FIG. 10. 1... Endoscope, 2... Light source unit, 3... Camera, 4... Subject, 13... Camera control circuit,
14... Light receiving element, 15... Release switch,
17...Light source control circuit, 18...Xe discharge lamp,
26...Shaft blade, 28...Aperture blade, 31
...Light guiding member, 32... Light receiving element, 137... Brightness indicator, 138... Bright switch, 139...
Dark switch, 144...PPI.

Claims (1)

[Scope of Claims] 1: a light source that generates at least observation light; an optical system that converges the light from the light source toward a light guide of a connected endoscope; and a combination of the light guide and the optical system. a light-guiding rod member having one end located in the peripheral end optical path of the convergent light from the optical system, and having a slope formed at the one end to substantially match the convergence angle of the convergent light from the optical system; , a light receiving element disposed at the other end of the light guiding member and detecting the amount of the observation light incident on the light guide of the endoscope; means for setting the brightness of the observation light; and detection of the light receiving means. An endoscope light source device comprising: a dimming means for measuring light and adjusting the detected light so that the brightness corresponds to the observation light set by the setting means.