JPH0215036B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a built-in structure of an electrical unit of a light wave distance meter, and is mainly used for measuring in a type of light wave distance meter that shares the objective lens of a collimating telescope and the objective lens of a distance measuring optical system. This invention relates to a structure in which a distance analog circuit is built into a device housing.

In recent years, optical rangefinders have adopted optical systems that share the objective lens of the collimating telescope and the objective lens of the ranging optical system in order to make them small and lightweight enough to be mounted on transshifts and theodolites. In addition, light wave ranging theodolites have been manufactured in which a light wave ranging system is incorporated into the telescope section of a conventional transit or theodolite, making it possible to measure not only distance but also angle. Furthermore, the angle can be detected photoelectrically using a photoelectric rotary encoder, and the distance measurement data and angle measurement data can be electronically displayed digitally, and the calculation processing between the distance measurement data and the angle measurement data can be performed. A so-called total station with multiple functions has been put into practical use.

By the way, the internal configuration of the lens barrel housing of a conventional optical distance meter is as shown in Fig. 1, where the lens barrel housing 1 is not shown. It is rotatably supported in a vertical plane. Inside the lens barrel housing 1, there is a collimating telescope consisting of an objective lens 2, a dichroic prism 3, a focusing lens 4, an erecting prism 5, a reticle plate 6, and an eyepiece 7, and the dichroic prism 3 is viewed from above and below. A light emitting element 8 and a light receiving element 9, which are arranged in a sandwiching manner, and condensing lenses 10 and 11 are arranged. The light emitting element 8 also includes a light emitting side analog circuit 1.
2, the light-receiving side analog circuit 13 is connected to the light-receiving element 9, and both analog circuits 12,
13 is connected to digital circuits 14a and 14b.

In the above-mentioned conventional light wave distance meter, a light-receiving side analog circuit that amplifies and processes a weak signal obtained by photoelectrically converting the weak distance measuring reflected light from the reflex reflector by a light-receiving element, and a light-emitting side analog circuit that drives a light-emitting element. Strong signals were mixed in, causing measurement errors. In order to prevent this, in the conventional light wave distance meter, as shown in FIG. Due to the need to downsize the lens barrel housing 1 so that it can be rotatably supported by a support column, the lens barrel housing 1 has been separated from the telescope near the collimating telescope.

Incidentally, optical devices generally require adjustment of optical axis alignment when assembling the device. In optical rangefinders as well, it is important to align the optical axes of not only the collimating telescope but also the ranging optical system, especially the positioning of the light receiving and emitting elements. In addition, it is preferable for measurement that the light intensity level of the ranging optical path incident on the light receiving element 9 and the light intensity level of the internal reference light intensity are the same level, so that the density filter 42 for adjusting the light intensity is set in advance to a predetermined value of the internal reference light intensity. The distance measuring light amount is controlled to a level of 1, and the distance measuring light amount is made to match the internal reference light amount using the density filter 43 for measurement. However, the amount of signal in the reference optical path is not constant depending on the light receiving and emitting elements built into the optical distance meter, and it must be adjusted while actually measuring the received light signal that has passed through the optical system. need to be adjusted. In addition, it goes without saying that the final adjustment of the electric circuit must be made under the same model environment as when it is actually assembled into the device and used for measurement. Final adjustment is required for each rangefinder.

However, as mentioned above, due to the necessity of separating the light-receiving and light-emitting element circuits, the conventional light wave distance meter is divided into a light-receiving-side analog circuit and a light-emitting-side analog circuit, each of which is independently arranged. Therefore, when making adjustments during assembly or maintenance, optical axis adjustment and light intensity level adjustment cannot be performed unless both of these separate analog circuits are incorporated into the optical distance meter. However, since both analog circuits are arranged so as to sandwich the optical system, adjustment is extremely difficult.To make adjustments, remove one of the analog circuits, adjust the optical system, and then re-adjust the analog circuit. The process of installing the analog circuit, then removing the other analog circuit and adjusting the optical system based on the measured data had to be repeated. In addition, the shielding characteristics of analog circuits change slightly each time they are removed or installed, so the measurement data changes each time, making it difficult to make adjustments based on the data before removal, and it takes a long time to make adjustments and assemble them. There were flaws that led to

The present invention was made to solve the above-mentioned drawbacks of the conventional light wave distance meter, and its structural feature is that the objective lens of the collimating telescope and the objective lens of the light wave distance measuring optical system are shared. In an optical distance meter in which an optical system is built in a telescope housing, both a light-emitting side analog circuit and a light-receiving side analog circuit are built in one side of the telescope housing with respect to the optical axis of the collimating telescope, and a digital circuit is built in. It is built into the other side of the telescope body.

The light wave rangefinder of the present invention configured as described above allows for the removal of the digital circuit, which operates normally even when connected to the analog circuit when separated from the optical system and placed outside the housing, during adjustment. Optical axis alignment and light intensity level adjustment can be performed extremely easily from the housing side where the digital circuit is housed. In addition, analog circuits always include optical systems, light receiving,
Since it is connected to the light emitting element, accurate measurement data can always be obtained, and electrical system adjustments and checks can be easily performed.

Furthermore, if the light amount level adjusting means is arranged in the reference optical path on the side opposite to the side where the analog circuit is built-in, the light amount level adjustment can also be conveniently performed from the side of the casing housing the digital circuit.

Embodiments of the present invention will be described below based on the drawings. As shown in FIGS. 2 and 3, the lens barrel housing 101 includes a central portion 150, an upper portion 152, and a lower portion 1.
It is divided into 55 parts. The central portion 150 includes an objective lens 102, an eyepiece lens 104, and an optical system 106.
is installed or stored. Optical system 106
The telescope consists of a collimating telescope system and a ranging optical system as shown in FIG. The upper part 152 includes a light receiving element unit 153, a light emitting element unit 154, a light emitting side analog circuit 112, and a light receiving side analog circuit 11.
An analog circuit 151 consisting of 3 is housed.
A digital circuit 114 is built into the lower part 155. As shown in FIG. 3, the light receiving element unit 153 includes a light receiving unit barrel 156, a light receiving element 157 built into the light receiving unit barrel 156, a condensing lens 158, and a light receiving optical fiber 15.
9. Consists of a first connector 160 and a second connector 162 for light-receiving optical fiber. The second connector 162 is fitted into an opening in the upper wall of the central portion 106 . The light emitting element unit 154 has a similar configuration to the light receiving element unit 153, and includes a light emitting unit barrel 165, a light emitting element 166 built in the light emitting unit barrel 165, a condensing lens 167,
It is composed of a light emitting optical fiber 168, a third connector 169 for the light emitting optical fiber, and a fourth connector 170. Further, a light amount level adjustment density filter 171 for the internal reference optical path is arranged at the lower part of the central portion 150. Rotating shaft 17
The density filter 171 supported by 2 is disk-shaped and has a transmittance that changes continuously in the circumferential direction. A rotating shaft 172 is pivotally supported through the lower wall of the central portion 150, and a knob 173 disposed in the lower portion 155 rotates the rotating shaft 172 and the density filter 171.

In the above configuration, it is desirable that the light-receiving side analog section 113 and the light-emitting side analog section 112 be independently shielded.

Next, the electric circuit of the light wave ranging system will be explained based on FIG. The light wave ranging system includes a light emitting side analog circuit 112, a light receiving side analog circuit 113, and a digital circuit 114. The light emitting side analog circuit 112 includes a reference oscillator 220 and a reference oscillator 22.
A first frequency divider 221 that inputs from 0 and outputs to the light emitting element 154, a second frequency divider 223 that inputs the first frequency divider 221, and the first frequency divider 221 and the second frequency divider 22.
3 and a first mixer 224 that inputs 3 and 3. The light receiving side analog circuit 113 includes the light receiving element 15
Preamplifier 222 input from 7, Preamplifier 2
22 and a first mixer 224 , and a waveform shaper 226 that inputs the second mixer 225 and outputs it to the digital circuit 114 . The digital circuit 114 includes a reference oscillator 220
A digital phase difference meter 227 to which the second frequency divider 223 and waveform shaper 226 input, a memory 230 to which the digital phase difference meter inputs, and a digital phase difference meter 2
27 and a memory 230 and outputs to a display 231. Digital circuit 114 further includes control circuit 232 . In the above configuration, it is desirable that the light-receiving side analog circuit 113 and the light-emitting side analog circuit 112 are each independently shielded. If further accuracy is required, it is desirable to shield all blocks shown in FIG.

In the above electric circuit, the reference frequency f ₀ =30 MHz from the reference oscillator 220 is divided by 1/20 by the first frequency divider 221 to create a signal of f ₁ =1.5 MHz. This signal is sent to the light emitting element 154, and the light emitting element 15
4 emits 1.5MHz infrared modulated light. The modulated light from the light emitting element 154 is sent to a reflector (not shown) placed at the target point via the objective lens 102 etc., where it is reflected and returned to the objective lens 102.
The light reaches the light receiving element 157 via etc. The light beam incident on the light receiving element 157 includes a 1.5 MHz component and a phase difference component depending on the distance to be measured. On the other hand, the signal of frequency f ₁ from the first frequency divider 221 is also supplied to the second frequency divider 223, where the frequency is divided by 1/500 to create a signal of f ₂ =3KHz. This signal is supplied to a first mixer 224 and a first frequency divider 22
1 to f ₁ signal difference frequency f ₃ ÷ f ₁ − f ₂ =
A 1497MHz signal is created. This signal of frequency f ₃ is further transmitted to the second mixer 2 of the analog circuit 213 on the light receiving side.
25. This second mixer 225 is connected to the output signal supplied from the preamplifier 222.
Create a beatdown signal from f ₁ − f ₃ = f ₂ . Since the signal from the light receiving element 157 has a phase difference component corresponding to the measured distance, the output signal of the second mixer 225 includes a signal of f ₂ =3KHz and a phase difference corresponding to the distance. Become. This signal is passed to the waveform shaper 226
After waveform shaping, the signal is supplied to the digital phase difference meter 227 of the digital circuit 214. 2nd frequency divider 2
The signal of frequency f ₂ from the reference oscillator 23 is supplied as a reference signal to the digital phase difference meter 227, which detects a phase difference according to the distance to be measured. It is measured digitally using a signal of ₀ , and the value is supplied to the computing unit 229 as ranging data.

As described above, since distance measurement is performed by a circuit having a large number of electric elements, response delays and drift phenomena of these electric elements affect the detection result of the phase difference, resulting in a measurement error.

For this reason, an internal reference optical path 240 that sends light from the light emitting element 154 directly to the light receiving element 157 inside the housing
By comparing the light passing through the ranging optical path and the light passing through the internal reference optical path, the influence of response delay of the electric circuit is removed. Switching between the internal reference optical path and the distance measuring optical path is performed by a shutter 241. The arithmetic unit 229 has a memory 23 in which data of the internal reference optical path 240 already measured by the same electric circuits as in the case of distance measurement is stored.
Arithmetic processing is performed between the data from 0 and the distance measurement data, and the data is corrected to a state free from the influence of response delay of the electric circuit, and the data is output to the display 231. In addition,
The above processing control is performed under the control of the control circuit 232.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the structure of a conventional optical distance meter, Figure 2
The figure is a vertical sectional view of the embodiment, FIG. 3 is a horizontal sectional view of the embodiment, and FIG. 4 is an electric circuit diagram of the embodiment. 101... Lens barrel housing section, 102... Objective lens, 104... Eyepiece lens, 112... Light emitting side analog circuit, 113... Light receiving side analog circuit, 1
14...Digital circuit, 150...Central part, 15
2... Upper part, 153... Light receiving element unit, 1
54...Light emitting element unit, 159...Light receiving optical fiber, 171...Light level adjustment density filter.

Claims (1)

[Scope of Claims] 1. In a light-wave distance meter built into a telescope housing of an optical system that shares the objective lens of a collimating telescope and the objective lens of a light-wave ranging optical system, the light-emitting side analog circuit and the light-receiving side An optical distance meter characterized in that both a side analog circuit and a side analog circuit are built into one side of the telescope housing with respect to the optical axis of the collimating telescope, and a digital circuit is built into the other side of the telescope body. 2. The light wave distance meter according to claim 1, wherein at least one of a light receiving element and a light emitting element is disposed on the side where the analog circuit is built-in. 3. The optical distance meter according to claim 1, wherein both the light receiving element and the light emitting element are arranged at a distance from each other on the built-in side of the analog circuit. 4. The optical distance meter according to claim 2 or 3, wherein the light receiving element and/or the light emitting element and the distance measuring optical system are connected by an optical fiber. 5. Claims characterized in that the light level adjusting means disposed in the internal reference optical path of the light wave ranging optical system is disposed on the opposite side to the analog circuit built-in side with respect to the optical axis of the collimating telescope. The optical distance meter according to any one of Items 1 to 4. 6. The optical distance meter according to any one of claims 1 to 5, wherein the light-receiving analog circuit is shielded from other circuits.