Optical adapter for a light-wave rangefinder

A liquid distance measuring apparatus, comprising:

• first light generation means for generating a distance measuring light modulated by given modulation signal;
• second light generation means for generating a reference light which is modulated by said given modulation signal, the wavelength of said reference light being different from the wavelength of said distance measuring light;
• photoconduction means for optically conducting said distance measuring light and said reference light wave;
• objective optical means including objective lens means for projecting at least said distance measuring light toward a target to be measured and for condensing at least a reflected distance measuring light reflected from the target, and light selection means for leading said distance measuring light exited from said photoconduction means toward the target and said reflected distance measuring light toward said photoconduction means respectively and for returning said reference light exited from said photoconduction means toward said photoconduction means;
• light receiving means for receiving both said reflected distance measuring light and said reference light which are returned through said photoconduction means;
• and
• distance measuring means for determining a distance between the target and the apparatus based on a time delay between said distance measuring light and said reflected distance measuring light.

For use with a light rangefinder having means for emitting a distance measuring light modulated by predetermined modulation frequency, means for receiving a reflected light from a target to which said distance measuring light is directed, first objective optical means for projecting said distance measuring light toward the target and for condensing said reflected light, and means for a time delay between said distance measuring light and said reflected light to determine the distance from the rangefinder to the target, an optical adapter comprising:

• optical relay means being substantially identical in structure with said first objective optical means;
• a first optical fiber connected at one end to said optical relay means for photoconducting said distance measuring light;
• a second optical fiber connected at one end to said optical relay means for photoconducting said reflected light;
• and
• second objective optical means connected to the other ends of said first and second optical fibers for projecting said distance measuring light transmitted through said first optical fiber toward the target and for directing said reflected light to said second optical fiber.

In a distance-measuring apparatus comprising light generation means for generating a light modulated by a given modulation frequency, objective optical means for projecting said light wave toward a target to be measured and for condensing a reflected light reflected from the target, light receiving means for receiving said reflected light, and determination means for determining the distance to the trget based on a time delay between said light said reflected light, said objective optical means comprising:

• an objective optical unit and an auxiliary optical unit;
• said objective optical unit containing a relay lens for forming an image of said light at a focal point thereof;
• said auxiliary optical unit containing an objective lens for projecting said light from the focal point toward the target and for condensing said reflected light at the focal point once again;
• and
• said auxiliary optical unit being connected to said objective optical unit by means of a rotatable support mechanism such that said auxiliary optical unit can be rotated with respect to said objective optical unit about the focal point as a center.

A liquid level heigh-measuring apparatus, comprising:

• a light wave generating means for generating a distance-measuring light wave modulated at a predetermined modulation frequency;
• an objective optical means for irradiating the distance-measuring light wave upon the surface of a liquid level to be distance-measured and collecting reflected distance-measuring light wave reflected from the surface of the liquid level to be distance measured;
• a light-receiving eans for receiving the reflected distance-measuring light wave from said objective optical means;
• a light wave transmission piping member for optically connecting said light wave generating means and said light-receiving means with said objective optical means;
• means to measure the height of the liquid level to be distance-measured on the basis of the time delay between the distance-measuring light waves and the reflected distance-measuring light waves connected to said light-receiving means;
• reference means for measuring the length of said light wave transmission piping member;
• said reference means being connected to receive light waves from said light wave generating means and transmitting said light waves to said light receiving means, and including
• a second light wave transmission piping member having a separate closed path from where it receives light waves from said light wave generating means to where it delivers said light waves to said light receiving means having a length substantially the length of said first-mentioned light wave transmission piping member.

A liquid level height-measuring apparatus, comprising:

• a light wave generating means for generating a distance-measuring light wave modulated at a predetermined modulation frequency;
• an objective optical means for irradiating the distance-measuring light wave upon the surface of a liquid level to be distance-measured and collecting reflected distance-measuring light wave reflected from the surface of the liquid level to be distance measured;
• a light-receiving means for receiving the reflected distance-measuring light wave from said objective optical means;
• a light wave transmission piping member for optically connecting said light wave generating means and said light-receiving means with said objective optical means;
• means to measure the height of the liquid level to be distance-measured on the basis of the time delay between the distance-measuring light waves and the reflected distance-measuring light waves connected to said light-receiving means;
• reference means for measuring the length of said light wave transmission piping member;
• said reference means being connected to receive light waves from said light wave generating means and transmitting said light wave to said light receiving means, and including
• a prism having at least two external reflecting surfaces included as part of said objective optical means located at the far end of said light wave transmission piping member from said light wave generating means and said light-receiving means and positioned to receive light waves from said piping member and reflecting said light waves generally toward the liquid surface and receiving light waves generally from the liquid surface and reflecting them to said piping member.