Distance measuring device

• US 7,327,440 B2
• Filed: 08/12/2005
• Issued: 02/05/2008
• Est. Priority Date: 08/16/2004
• Status: Expired due to Fees

• Current Assignee: James N. Horn
• Original Assignee: James N. Horn
• Inventors: Horn, James N
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): BRAINARD, TIMOTHY A
• Application Number:
  US11/202,976
• Publication Number:
  US 20060044545A1
• Time in Patent Office: 907 Days
• Field of Search: 356/4.01
• US Class Current: 356/4.03
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors

Abstract

A distance measuring device is disclosed which can measure the distance to an object located within a known range. The device uses beam splitters and lenses to focus and direct energy reflected from an object onto at least two bi-sensors. The bi-sensors each have an inner sensing area and an outer sensing area. When the device has been properly calibrated, the reflected energy will be focused such that almost all of it will fall into the inner sensing area of one be-sensor when the object is at the minimum distance in the known range and when the object it at the maximum distance almost all of the energy will fall onto the inner sensing area of the other sensor. The distance to an object is calculated by comparing the ratio of the energy on the inner sensing areas of the two sensors with a table of known ratio verses distance values.

Claims

1. A device for measuring distance over a known range comprising:

a laser, a first beam splitter, a lens, a second beam splitter, a first sensor, and a second sensor;

the laser being configured to emit energy at an object;

the first splitter being configured to direct emitted energy along a straight line away from the device, and to direct energy, reflected from the object, toward the lens;

the lens configured to focus the reflected energy onto the second splitter;

the second splitter configured to split the focused energy into a number of beams that corresponds to the number of sensors;

each of the sensors having a photo sensitive surface that is divided into at least two sensing areas such that the surface has an inner sensing area and an outer sensing area; and

the lens being shaped and the sensors being positioned such that when the object is at the minimum distance of the known range, almost all of the energy focused on the first sensor will be focused on the inner sensing area, and when the object is at the maximum distance of the known range almost all of the energy focused on the second sensor will be focused on the inner sensing area.

2. The device of claim 1 wherein the ratio of the energy level measured by the inner sensing area of the first sensor and the energy level measured by the inner sensing area of the second sensor is unique for all distances over the known range, and the distance to the object is determined by determining the ratio.

3. The device of claim 2 further comprising means for determining the ratio of the energy level measured by the inner sensing area of the first sensor and the energy level measured by the inner sensing area of the second sensor and determining the distance to the object based on the ratio.

4. The device of claim 3 wherein the means for determining the ratio of the energy level measured by the inner sensing area of the first sensor and the energy level measured by the inner sensing area of the second sensor and determining the distance to the object based on the ratio is a micro processor that has a table of the distance for each value of the ratio stored therein and the sensors are further configured to provide input to the micro processor;

and

the microprocessor is programmed to receive input from the sensors, determine the ratio, compare the ratio to the table to determine the distance to the object and transmit the determined distance.

5. The device of claim 4 further comprising means for displaying the distance from the device to the object and wherein the microprocessor provides input to said means such that the distance to the object is displayed.

6. The device of claim 1 further comprising means for causing the device to emit energy at an object.

7. A device for measuring distance over a known range comprising:

a laser, a first lens, a second lens, a first sensor, and a second sensor;

the laser being configured to emit energy at an object along a straight line away from the device;

the first lens being configured to focus the energy, reflected from the object, onto the first sensor;

the second lens being configured to focus the energy, reflected from the object, onto the second sensor;

each of the sensors having a photo sensitive surface that is divided into at least two sensing area such that the surface has an inner sensing area and an outer sensing area;

the first lens being shaped and the first sensor being positioned such that when the object is at the minimum distance of the known range, almost all of the energy focused on the first sensor will be focused on the inner sensing area;

the second lens being shaped and the second sensor being positioned such that when the object is at the maximum distance of the known range, almost all of the energy focused on the second sensor will be focused on the inner sensing area.

8. The device of claim 7 wherein the ratio of the energy level measured by the inner sensing area of the first sensor and the energy level measured by the inner sensing area of the second sensor is unique for all distances over the known range, and the distance to the object is determined by determining the ratio.

9. The device of claim 8 further comprising means for determining the ratio of the energy level measured by the inner sensing area of the first sensor and the energy level measured by the inner sensing area of the second sensor and determining the distance to the object based on the ratio.

10. The device of claim 9 wherein the means for determining the ratio of the energy level measured by the inner sensing area of the first sensor and the energy level measured by the inner sensing area of the second sensor and determining the distance to the object based on the ratio is a micro processor that has a table of the distance for each value of the ratio stored therein and the sensors are further configured to provide input to the micro processor;

and

the microprocessor is programmed to receive input from the sensors, determine the ratio, and compare the ratio to the table to determine the distance to the object.

11. The device of claim 10 further comprising means for displaying the distance from the device to the object and wherein the microprocessor is programmed to provide input to said means such that the distance to the object is displayed.

12. The device of claim 10 wherein the microprocessor is programmed to provide the distance to the object as an input signal to a higher level processor.