JPS6287831A - How to align the optical axis in a light transmittance measuring device - Google Patents

Abstract

PURPOSE:To make is possible to take a rapid measure when the non-coincidence of optical axes was generated during operation, by outputting light or sound by an alarm means when the optical axis of a floodlight projector coincides with that of a light receiver. CONSTITUTION:The luminous flux 11 from a floodlight projector 1 is projected to a light receiver 2 and the floodlight projector 1 or the light receiver 2 is adjusted by an optical axis adjusting mechanism while it is confirmed whether the effective diameter (d) of the light receiving area of the light receiver 2 enters the diameter D of the luminous flux 11 by an alarm means (light emitting diode or buzzer). When the effective diameter (d) of the light receiving area is included in the diameter D of the luminous flux 11, the coincidence of optical axes is confirmed by the output from the alarm means and, thereafter, the luminous flux 11 of the floodlight projector 1 is contracted by an iris 5. The adjustment of the floodlight projector 1 and the light receiver 2 is performed by the optical axis adjusting mechanism while it is confirmed whether the effective diameter (d) of the light receiving area coincided with the diameter D' of contracted luminous flux by the alarm means to align the optical axes of both of them.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for aligning the optical axes of a light emitter and a light receiver in a light transmittance measuring device, and particularly relates to a method for aligning the optical axes of a light emitter and a light receiver. The present invention relates to an optical axis alignment method that allows easy confirmation of whether or not the object is present.

[Conventional technology]

Figure 2 is a schematic configuration diagram showing a light transmittance measuring device used, for example, to measure the concentration of smoke passing through a flue. (B) is a diagram showing the state during accurate optical axis adjustment, and Figure 3 is a rear view showing the projector and its optical axis adjustment tank in Figure 2, and Figure 4 is a side view of Figure 3. , FIG. 5 is an explanatory diagram showing the positional deviation of the light beam from the projector.

In FIG. 2, 1 is a light projector, and 2 is a light receiver, and both are installed facing each other on both sides of the light transmission chamber measurement location so that their light projecting surfaces and light receiving surfaces face each other.

The light projector 1 includes a light emitting element 3, a pinhole plate 4 located in front of the light emitting element 3, a diaphragm 5, and a light projecting lens system 6 facing the light emitting element 3 via the pinhole plate 4,
The diaphragm 5 is movably provided between the pinhole plate 4 and the light projection lens system 6 so that a person can come out.
The light receiver 2 also includes a slit plate 7, a condensing lens 8, and a light receiving element 9 facing the slit plate 7 through the condensing lens 8.
, and an amplifier 10 connected to the light receiving element 9 to amplify its output.

Here, the field of view seen from the light receiving element 9 of the light receiver 2 is limited by the slit of the slit plate 7 located in front of the condenser lens 8, and is defined so that the effective diameter d of the light receiving area is a certain size. The light emitted from the light emitting element 3 of the projector 1 is limited in its spread angle by the pinhole in the pinhole plate 4 in front of it, and enters the projecting lens system 6. The diameter of the light beam 11 on the photoreceiver 2 side is determined by the system 6 so that it becomes appropriately larger than the effective diameter d.

In other words, if the diameter of the luminous flux from the projector 1 is too large,
The illuminance of the light received through the slit of the slit plate I, which defines the effective light-receiving area of the light receiver 2, decreases, making it impossible to obtain the amount of light that satisfies the light-receiving sensitivity of the light-receiving element 9, making it difficult to measure the light transmittance. On the other hand, if the diameter is too small, the amount of light to the light-receiving element 9 will be sufficient, but it will be DΣd. Therefore, if the emitter 1 and the receiver 2 move due to vibrations, etc., as shown in FIG. As a result, the effective diameter d of the light receiving area is
The slit 7a of the slit plate 7 protrudes,
The amount of received light decreases, making it impossible to accurately measure light transmittance.

Therefore, as described above, the diameter of the light beam from the projector 1 is set to be appropriately larger than the effective diameter d of the light receiving area of the light receiver 2 to prevent the slit 7a from protruding and to increase the light receiving sensitivity of the light receiving element 9. This ensures that a satisfactory amount of light is obtained.

Further, the amount of light along the diameter of the above-mentioned light beam 11 on the receiver 2 side is designed to have uniform illuminance with uniform intensity at each part. The reason for this is that if the illuminance of the light beam 11 is non-uniform on the light receiver 2 side, and if the optical axes of the emitter 1 and the light receiver 2 move relative to each other due to vibration etc., the effective diameter d of the light receiving area 11, the measurement result of the light transmittance will be different depending on which part of the light beam 11 is matched.Therefore, in order to eliminate such inconvenience, the amount of light in each part of the light beam 11 on the receiver 2 side should always have a uniform illuminance. This is because something becomes necessary.

Furthermore, the movable aperture 5 of the projector 1 is shown in FIG.
), when placed between the pinhole plate 4 and the light emitting lens system 6, the diameter 6 of the light beam 11 reaching the light receiver 2 side is approximately equal to the effective diameter d of the light receiving area. I'm trying to make it happen. In other words, the diaphragm 5 functions to compress the light beam 11 from a diameter to a smaller diameter.

Next, in FIGS. 3 and 4, 12 is an optical axis adjustment mechanism, and the optical axis adjustment mechanism 12 is connected to a support base 13 and this support base 1.
3, and optical axis adjustment screws 15 and 16 attached to the rear side of the support base 13. And the support stand 13 of this optical axis adjustment mechanism 12
The projector 1 is mounted on top, and its tip is supported at one point by a fulcrum 14 so that it can freely rotate vertically and horizontally, and the rear part of the projector 1 is mounted with a horizontal optical axis adjustment screw 15.
and vertical optical axis adjustment screw 16iCson-t"n.

engaged.

In addition, in FIG. 3, 17 is provided at the back of the projector 1.
This is the terminal.

In a light transmitting device having such a structure, a method of aligning the optical axis as shown in, for example, Japanese Patent Application No. 59-225537 has been conventionally employed, and the method will be explained below.

That is, the light emitter 1 and the light receiver 2 are connected via a cable or the like (not shown) so that the signal from the light receiving element 9 of the light receiver 2 shown in FIG. 2 is sent to the light emitter 1 via the amplifier 10. A measuring device such as a synchroscope (not shown) is connected to the terminal 17 (see FIG. 3) of the light projector 1 so that the level of the signal from the light receiving element 9 can be monitored.

Therefore, when the light emitting element 3 is made to emit light with the aperture 5 of the projector 1 retracted from between the pinhole plate 4 and the projecting lens system 6, as shown in FIG. 2(A), the light is focused. The magnification limited by the pinhole of the hole plate 4 enters the light projecting lens system 6 at an angle, and is projected by the light projecting lens system 6 to the light receiver 2 as a radial beam 11.

When a part of this light beam 11 passes through the slit of the slit plate 7 and is received by the light receiving element 9 via the condensing lens 8, a signal corresponding to the amount of light is output from the light receiving element 9.
After being amplified by the amplifier 10, the signal is sent to the projector 1 via a cable (not shown), so the worker monitors the level of this signal with a measuring device (not shown) while reading the third signal.
The horizontal and vertical angles of the projector 1 are adjusted using the optical axis adjustment screws of the optical axis adjustment mechanism 12 shown in FIGS.

That is, the optical axis is aligned so that the effective diameter d of the light-receiving area of the light receiver 2 falls within the diameter of the light beam 11 projected from the projector 1, or in other words, the slit 7a of the slit plate T falls within the diameter.

At this stage, the effective diameter d of the light receiving area is not necessarily at the center of the diameter of the light beam 11, so if the emitter 1 or receiver 2 moves slightly due to vibration etc. There is a risk that the diameter d may protrude.

Therefore, next, the diaphragm 5 of the emitter 1 is moved and positioned between the pinhole plate 4 and the emitter lens system 6, and thereby the luminous flux 11 being emitted to the receiver 2 is changed from the diameter. Reduce it to diameter D'. At this time, the diameter D' of the light beam 11 and the effective diameter d
If the cylindrical slit plate T'7a does not match, the amount of light received by the light receiving element 9 will decrease and a signal of a certain level will not be obtained. While monitoring the level, adjust the optical axis adjustment mechanism 1 again.
2. Optical axis adjustment screw 15. t6 to the left and right of the projector 1.

By finely adjusting the vertical angle, the diameter D' of the light beam 11 is made to match the slit 7a of the slit plate 7.
After accurately aligning the optical axes of the light transmitter 2 and the light receiver 2, the diaphragm 5 is retracted from between the pinhole plate 4 and the light emitting lens system 6 to the outside thereof, and the light transmittance measuring device is ready for measurement. state.

[Problem that the invention seeks to solve]

As explained above, the conventional method for aligning the optical axis in a light transmittance measuring device is to connect a measuring device to the emitter, and adjust the optical axis while monitoring the level of the signal sent from the receiver to the emitter with the measuring device. However, the locations where light transmittance measurement devices are usually installed are often remote locations.
On the other hand, the measuring device is usually removed from the projector and taken home after the optical axis alignment is completed.

Therefore, with conventional methods, there is no way to check the mismatch of optical axes while the equipment is operating, and if a mismatch of optical axes is predicted from an abnormality in the light transmittance data, it is necessary to prepare a measuring device and check. In addition, since a measuring device is also required to readjust the optical axis, there is a problem in that when a mismatch in the optical axes occurs during operation of the apparatus, it is not possible to promptly deal with the mismatch.

The easiest way to solve this problem would be to always have the measuring device near the installation location of the light transmittance measuring device, but the frequency with which it is necessary to readjust the optical axis is It is not practical to always have low-priced and therefore expensive measuring instruments on hand.

The present invention has been made to solve such problems, and is capable of quickly dealing with mismatches in optical axes that occur during operation of the device, and can be implemented at low cost. The purpose of this invention is to realize a method for aligning the optical axis in a light transmittance measuring device.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention includes a notification means such as a light emitting diode or a buzzer that outputs light or sound when the optical axes of the emitter and the receiver of the light transmittance measuring device coincide.
It is provided in the light emitter or light receiver.

[Effect]

In the present invention having the above-described configuration, a light beam is projected from a light projector to a light receiver, and the notification means confirms whether or not the effective diameter of the light receiving area of the light receiver is within the diameter of this light beam. The emitter or receiver is adjusted by the optical axis adjustment mechanism, and after the effective diameter of the light-receiving area is within the diameter of the luminous flux and the alignment of the optical axes is confirmed by the output from the notification means, the luminous flux of the emitter is adjusted. is contracted by a diaphragm, and the transmitter or receiver is adjusted by the optical axis adjustment mechanism while checking by the notification means whether the diameter of the contracted luminous flux matches the effective diameter of the light-receiving area. to align the optical axes of both.

Therefore, according to this, it is possible to align the optical axes without using expensive measuring equipment as in the past, and even if a discrepancy in the optical axes occurs during operation of the device, the optical axis can be adjusted using the notification means. It is possible to know the occurrence of a mismatch, and also to readjust the optical axis. Since a light emitting diode, a buzzer, etc. is used as the notification means, it can be realized at low cost.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing a notification means and its driving circuit used in an embodiment of the optical axis alignment method according to the present invention. A first amplifier connected via a resistor, 20 a bandpass filter (BPF) connected to the first amplifier 19, 21 a second amplifier connected to the bandpass filter 20, and 22 a bandpass filter (BPF) connected to the first amplifier 19; A light emitting diode (LED) is connected to the amplifier 21 of No. 2 through a commutator etc.
).

This light emitting diode 22 is attached at the position of the terminal 17 provided on the back of the floodlight 1 shown in FIG.
Other circuit components 18a, 18b-21 are assembled in the projector 1 shown in FIGS. 2-4.

The input terminals 18a, 18b are connected to the output terminal of the amplifier 10 of the photoreceiver 2 shown in FIG. 2 via cables (not shown).
The first amplifier 19 connected to the optical receiver 2b is a high chi/beadance circuit so as not to affect the output signal level of the amplifier 10 of the photoreceiver 2.

Further, the bandpass filter 20 is used to prevent the light emitting diode 22 from lighting up due to noise, and its output power is amplified to a specified level by the second amplifier 21, and the output power is amplified to a specified level by the second amplifier 21. The light emitting diode 22 is turned on in response to an input voltage.

The projector 1 used in this embodiment is the same as that shown in FIG. 2 except that it includes the circuit shown in FIG. 1, and the receiver 2 is also the same. Also, those shown in FIGS. 3 and 4 are used.

Next, a method for aligning the optical axis using the above-mentioned apparatus will be explained.

First, as shown in FIG. 2 (4), when the light emitting element 3 is made to emit light with the aperture 5 of the projector 1 retracted from between the pinhole plate 4 and the projecting lens system 6, the light is focused. The light enters the light emitting lens system 6 with a divergence angle limited by the pinhole of the hole plate 4, and is emitted by the light emitting lens system 6 to the light receiver 2 as a beam 11 of diameter. The optical axis adjustment screw 15 of the optical axis adjustment mechanism 12 shown in FIGS. 3 and 4.
Adjust the left and right and up and down angles of the floodlight 1 by 16,
Roughly align the optical axes of the emitter 1 and receiver 2.

That is, the optical axis is aligned so that the effective diameter d of the light-receiving area of the light receiver 2 falls within the diameter of the light beam 11 projected from the light emitter 1, or in other words, the slit γa of the slit plate 7 falls within the diameter.

In this case, whether or not the slit 7a is within the diameter of the light beam 11 is confirmed by checking the state of the light emitting diode 22 as a display means provided on the back surface of the projector 1.

That is, when a part of the light beam 11 projected onto the light receiver 2 passes through the slit 7a of the slit plate 7 and is received by the light receiving element 9 via the condensing lens 8, a signal corresponding to the amount of light is output. , input terminal 18 on the projector 1 side via the amplifier 10
a, 18b as an input voltage.

This input voltage is applied to the first amplifier 1 of the drive circuit shown in FIG.
9. The light beam 11 is outputted to the light emitting diode 22 through the bandpass filter 20 and the second amplifier 21.
If the slit γa protrudes from within the diameter of 22 will not be lit.

However, when Surin) 7a enters within the diameter of the light beam 11,
Since the amount of light received by the light-receiving element 9 is a specified amount, the input voltage to the drive circuit becomes equal to or higher than a certain voltage, thereby lighting up the light-emitting diode 22.

Therefore, depending on whether the light emitting diode 22 is lit or not,
Adjustment can be made by determining whether or not the slit 7a is within the diameter of the light beam 11.

In this way, the optical axis is roughly aligned, but at this stage, the effective diameter d of the light-receiving area is 1
Therefore, if the projector 1 or receiver 2 moves even slightly due to vibration or the like, the effective diameter d may protrude from the diameter of the light beam 11.

Therefore, next, the diaphragm 5 of the emitter 10 is moved and positioned between the pinhole plate 4 and the emitter lens system 6, and thereby the light beam 11 being projected onto the receiver 2 is changed from the diameter to the diameter. Reduce it to D'. At this time, if the diameter d of the light beam 11 and the effective diameter d of the light-receiving area do not match, the amount of light received by the light-receiving element 9 will decrease, and for the same reason as the rough optical axis alignment described above, the light-emitting diode 22 will not light up.

Therefore, while checking whether the light emitting diode 22 is lit or not, finely adjust the horizontal and vertical angles of the projector 1 using the optical axis adjustment screws 15 and 16 of the optical axis adjustment mechanism 12, and adjust the luminous flux 11.
After making sure that the diameter 6 of the light-emitting diode 22 matches the effective diameter of the light-receiving area. and the light projecting lens system 6 to the outside thereof, and the light transmittance measuring device is brought into a measurable state.

This completes the optical axis alignment, but when checking whether a mismatch of optical axes has occurred during operation of the device, it can be determined based on whether or not the light emitting diode 22 is lit.
If the light emitting diode 22 does not light up and it is confirmed that the optical axes do not match, the optical axes may be aligned by readjusting as described above.

In the above-mentioned embodiment, the case where the light emitting diode 22 and its driving circuit are provided in the light projector 1 has been described, but the present invention is not limited to this. For example, the light emitting diode 22 and its driving circuit are provided in the light receiver 1. In this case, the optical axis adjustment mechanism 12 may also be combined with the light receiver 2, and the optical axis adjustment may be performed on the light receiver 2 side.

Further, the notification means for notifying that the optical axes of the emitter 1 and the light receiver 2 are aligned does not necessarily have to be the light emitting diode 22 that outputs light, but may be a notification means that outputs sound, such as a buzzer, for example. Good too.

〔Effect of the invention〕

As explained above, the present invention provides a notification means that outputs light or sound when the optical axes of the emitter and the receiver coincide,
This notification means is used to check whether the optical axes of the emitter and receiver are aligned, and the optical axis adjustment mechanism is used to adjust the angle of the emitter or receiver to align the optical axes of both. Since optical axis alignment can be easily performed at all times without using a measuring device as in the conventional method, the following effects can be obtained.

That is, while the light transmittance measuring device is in operation, the discrepancy in the optical axes can be easily confirmed by the notification means, and even if discrepancy in the optical axes is predicted from an abnormality in the light transmittance data, this can be easily confirmed. In addition, if readjustment of optical axis alignment is necessary in these cases, the adjustment work can be easily performed, so even if optical axis misalignment occurs while the equipment is operating, it can be quickly corrected. can be dealt with.

Further, since the notification means uses simple parts such as a light emitting diode and a buzzer, it can be realized at a much lower cost than when using conventional expensive measuring instruments.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the notification means and its driving circuit used in an embodiment of the present invention, FIG. 2 is a schematic diagram showing a light transmittance measuring device, and FIG. 3 is a diagram showing the projector in FIG. FIG. 4 is a rear view of the optical axis adjustment mechanism, FIG. 4 is a side view of FIG. 3, and FIG. 5 is an explanatory diagram showing deviation of the light beam. 1... Emitter 2... Light receiver 3... Light emitting element
5... Aperture 9... Light receiving element 12... Optical axis adjustment mechanism 19... First amplifier 20... Bandpass filter 21... Second amplifier 22... Light emitting diode patent Applicant Oki Electric Industry Co., Ltd. Hitachi Plant Construction Co., Ltd. Agent Patent attorney Takashi Kanakura Two engravings of the drawings (L without any changes to the content) Circuit diagram showing an embodiment of the present invention 1 Rear view of the optical axis adjustment mechanism 3 Side view of Figure 3 4 Explanatory diagram showing the deviation of the national luminous flux 51 Procedural amendment (Mutsu) January 16, 1985 Michibe Uga, Commissioner of the Patent Office 1, Indication of the case 1985 Special Patent Application No. 227903 2, Title of Invention Optical axis alignment method in light transmittance measuring device 3
, Relationship with the case of the person making the amendment Patent applicant address 1-7-12 Toranomon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. Representative Nankai Hashimoto, male 4, agent 1-” 1 5. Date of amendment order (voluntary) 7. Contents of amendment 1. Bright, amend "indicates complete arrangement" to "indicates arrangement mechanism" on page 2, line 12 of the series number. 2. "Effective diameter" on page 16, line 12 of the specification is corrected to "effective diameter d". Procedural Amendment (-j5 Vision February 4, 1986 Michibe Uga, Commissioner of the Patent Office 1, Indication of the case 1985 Patent Application No. 227903 2, Title of the invention Optical axis alignment in a light transmittance measuring device Method 3
, Relationship with the case of the person making the amendment Patent Applicant Address 1-7-12, Toramon, Minato-ku, Tokyo Name (029) Oki Electric Industry Co., Ltd. Representative Nankai Hashimoto (1 person per week) 4. Agent 5, date of amendment order: January 8, 1986! −′°′−
-Rear force- 7. Correction details 1 Figures 1, 2, 3, 4, and 5 are corrected as shown in the attached sheet.

Claims (1)

[Claims] 1. The emitter and the receiver of the light transmittance measuring device are arranged to face each other, and an optical axis adjustment mechanism is provided on one of the emitter and the receiver, so that the light beam from the emitter to the receiver is In an optical axis alignment method for a light transmittance measuring device, in which the optical axis of the emitter or the receiver is adjusted by an optical axis adjustment mechanism to align the optical axes of both, when the optical axes are aligned, light or sound is emitted. The emitter or receiver is provided with a notification means that outputs the same, and the angle of the emitter or receiver is adjusted by an optical axis adjustment mechanism while checking whether the optical axes of the emitter and receiver are aligned using this notification means. A method for aligning an optical axis in a light transmittance measuring device, characterized by: