KR20120017889A - Optical sensor for distance measurement and its module - Google Patents

Abstract

The present invention relates to a distance measuring sensor, and more particularly, to a distance measuring sensor and a module using light emitting and light receiving elements.
Distance measuring sensor of the present invention and the light emitting device for emitting light to the object for distance measurement; A lens unit formed between the light emitting element and the optical path of the object; And a light receiving unit in which a plurality of photo-voltage conversion elements for receiving light from the object are arranged.
The distance sensor of the present invention is provided by a new type of distance sensor using a photodiode, and can eliminate the difference according to the reflectance of the detector. It is possible to apply to various fields.

Description

Optical sensor for distance measurement and its module {PHOTO SENSOR FOR DISTANCE AND MODULE THEREOF}

The present invention relates to a distance measuring sensor, and more particularly, to a distance measuring sensor and a module using light emitting and light receiving elements.

In areas such as cleaning robots, distance measurement is an important technical factor. As the distance measurement, a measuring method using ultrasonic waves and a measuring method using light are known.

Patent Publication No. 2009-39208 filed by Samsung Electronics Co., Ltd. discloses a distance measuring module using an infrared sensor. As shown in FIG. 1, the disclosed module for distance measurement includes an infrared LED 115 emitting infrared light to an object 170 and a light emitting part lens 111 forming the emitted infrared light as parallel light. It consists of a light emitting unit 110, a light receiving unit lens 151 for condensing infrared light reflected from the object and a Position Sensing Device (PSD) sensor 155 for measuring the distance to the object through the focused infrared light And a light receiving unit 150, wherein the light emitting unit and the light receiving unit are disposed to maintain a predetermined angle between the optical axis of the infrared light emitted from the light emitting unit and the optical axis of the infrared light collected by the light receiving unit.

The PSD is a method of measuring the resistance value between channels depending on the location of the barrier caused by light. It is easy and accurate to detect the location of light incident, but it is difficult to make a device. Barriers are created, resulting in less accuracy, and additional circuitry is needed to measure resistance. The distance measurement method using the PSD has a problem that only one-dimensional position can be measured.

In addition, conventional measurement methods have a problem in that the measured value varies depending on the degree of reflection of the reflector.

Accordingly, there is a demand for an apparatus for a new distance measuring method which can measure not only a simple distance but also a degree of deflection, an error according to the degree of reflection of a reflector, and which is convenient to manufacture.

The problem to be solved in the present invention is to provide a new distance measuring sensor and module using an optical element.

Another problem to be solved by the present invention is to provide a new distance measuring sensor and its module capable of measuring distance measurement and deflection.

Another problem to be solved by the present invention is to develop a sensor that can measure the distance using light using the output voltage without additional circuitry, to achieve productivity improvement and product miniaturization due to the simplification of the product.

In order to solve the above problems, the distance sensor and the module according to the present invention includes a light emitting device for emitting light to the object for distance measurement; A lens unit formed between the light emitting element and the optical path of the object; And a light receiving unit in which a plurality of photo-voltage conversion elements for receiving light from the object are arranged.

Although not limited in theory, as the distance to the object changes, the position at which the reflected light of the object is reflected in the light receiving unit is changed, and thus, the output of each photo-voltage conversion element arranged in the light receiving unit measures the change. It will be possible to measure the position of the object.

In the present invention, the plurality of light-to-voltage conversion elements may use a device that outputs a voltage signal by the reflected light reflected from the target object. In the practice of the invention, the photo-voltage converter may be composed of a photodiode in which the amount of current outputted by the amount of light changes and the amount of current converted into a voltage.

In the present invention, the photo-voltage converter may be arranged in contact with two or more photo-voltage converters in a direction away from the position adjacent to the light emitting device. In the embodiment of the present invention, the photo-voltage conversion element may be arranged in a straight line in a direction away from the adjacent position by connecting the elements of the rectangular shape. The rectangular elements may be arranged in one or more columns, preferably in one, two, or three columns, thereby measuring distance and left and right deflection, that is, coordinates, with the object.

In the present invention, it is preferable that a lens for condensing the reflected light reflected from the object on the surface of the light-voltage conversion element is formed in the optical path between the object and the light-voltage conversion element. The reflected light may pass through the lens and be focused on the surface of the light-to-voltage conversion element in the form of a spot. The spot size may be adjusted in consideration of the width of each photo-voltage conversion element.

In the present invention, the distance measuring sensor and the module when the distance to the object is close, the reflection angle is wide and is focused on the conversion element located at a remote location from the light emitting element, when the distance to the object is far away the reflection angle is narrow light emitting device From the condensation is made to the conversion element located adjacent to.

In the practice of the present invention, the distance measuring sensor and the module comprises a printed circuit board or a lead frame; A light emitting unit including a light emitting diode mounted on one side of the substrate; A light emitting side condensing lens for condensing the emitted light to an object, a light receiving side condensing lens for condensing light reflected from the object to a light receiving unit, and a plurality of parallel-connected light-to-voltage conversions for receiving light from the light receiving side condensing lens A light receiving unit comprising an element; And a spacer that optically isolates the light emitting portion and the light receiving portion.

The light emitting diode may use an infrared diode, and it is preferable to use parallel light. The separation unit may be implemented by using a black injection molding formed with a slit in which a lens may be installed on the upper portion, or may be implemented in a mold form.

In accordance with an aspect of the present invention, a distance measuring sensor and a module thereof include: a light emitting device emitting light to an object for distance measurement; A plurality of light receiving elements that receive light from the object are connected to each other, and the light receiving elements are characterized in that the output of the light receiving element changes in accordance with the distance to the object.

In the present invention, the distance measuring sensor and the module is moved from the light receiving element located far from the light emitting element to the light receiving element located far from the light emitting element as the incident region of the reflected light is far from the target object. Accordingly, the output of the light receiving elements located far from the light emitting device is reduced and the output of the light receiving elements adjacent to the light emitting device is increased.

The present invention provides a new type of distance sensor using a photodiode. The distance sensor according to the present invention can eliminate the difference according to the reflectance of the detector and can be applied to various fields by using the photo-voltage conversion element, which enables a small sized distance measuring sensor without additional external circuit.

1 is an explanatory diagram showing a distance sensor according to the prior art.
2 is a conceptual diagram using a cross section of a distance sensor according to the present invention.
3 is a plan view of two light receiving sensors arranged on a printed circuit board.
4 is a circuit diagram of the light receiver of FIG. 3.
FIG. 5 is a diagram illustrating that light moves in accordance with a distance in the light receiving unit of FIG. 3.
6 is a plan view of a state in which two light receiving sensors are arranged in two rows on a printed circuit board.
FIG. 7 is a circuit diagram of the light receiver of FIG. 6.
FIG. 8 is a view illustrating that light moves in accordance with a distance and coordinates in the light receiving unit of FIG. 6.
9 is a plan view of three light receiving sensors arranged on a printed circuit board.
FIG. 10 is a circuit diagram of the light receiver of FIG. 9.
11 is a graph showing the relationship between the detector distance and the voltage output value.
12 is a graph showing the difference between optical elements according to the detector distance.
4 is a plan view and a circuit diagram of a distance sensor in which four light receiving sensors are arranged in two rows.
5 is an explanatory diagram illustrating the light movement of the light receiving sensor.
Figure 6 shows the light output of the light receiving sensor

Hereinafter, the present invention will be described in detail through examples. Although the present invention has been described in detail, it is intended to illustrate the invention and is not intended to limit the content of the invention.

As shown in FIG. 2, in the distance measuring sensor 100 according to the present invention, a light emitting device 11 and two photo-voltage conversion devices 12 and 13 are mounted on a printed circuit board 10. An injection molding cover 14 is formed around the 11 and the photo-voltage conversion elements 12 and 13 to prevent mutual light transmission and disturbance light, and a slit for passing light is formed at the upper end of the injection molding cover. The light emitting part lens 15 and the light receiving part lens 16 are respectively formed in the slit.

The light emitted from the light emitting element 11 passes through the light emitting unit lens 15, is reflected by the reflecting member 20, passes through the light receiving unit lens 16, and enters the light-voltage conversion element 13. When the distance of the reflective member 20 increases, the reflected light passes through the light receiving part lens 16 and enters the light-voltage conversion element 12.

As shown in FIGS. 3 to 5, the photo-voltage conversion element applies a driving voltage 303 and a GND 304 as a reference and is proportional to the amount of light entering the separated light receiving surfaces 12 and 13 of the element. It converts to one voltage and outputs it using the individual voltage output terminals 305 and 306. The voltage output terminal 307 is formed by comparing the outputs of the two light receiving surfaces through the differential amplifier with respect to the light converted into voltage. The distance conversion is converted into a distance by grasping the position of the light irradiated to the light-receiving surface according to the distance of the reflective member 20.

The light from the light emitting element 11 is better through the light emitting lens 15 and the light reflected on the surface of the reflective member 20 is focused on the light receiving surfaces 301 and 302 of the light-voltage conversion element through the light receiving lens 16. Is formed, and as the distance of the reflective member 20 increases, the focus moves in a direction adjacent to the light emitting element 11.

As a result, the voltage output terminals 305 and 306 of the photo-voltage device have the light-receiving surface output of the photo-voltage device 12 adjacent to the light emitting device 11 when the distance of the reflecting member 20 increases, as shown in FIG. 11. This increases relatively. The position of the light incident on the light receiving surfaces 12 and 13 may be estimated using the following equation.

[Equation 1]

Light incident position = [light receiving surface (12) output-light receiving surface (13) output] / total output

When calculated by applying the above formula is converted as shown in FIG. The position of incidence of light is within the range of -1 to 1 and the distance is converted using the value of the linear section shown in FIG. By using the above equation, since the same value is obtained regardless of the reflectance of the detector, the same distance can be calculated regardless of the type of the reflecting member 20.

In another embodiment of the present invention, as shown in FIGS. 6 to 8, when the light receiving surfaces 308, 309, 310, and 311 of the four photo-voltage conversion elements are formed, the reference to the photo-voltage element is used. The driving voltage 303 and the GND 304 are applied and converted to voltages proportional to the amount of light entering the separated light receiving surfaces 308, 309, 310, and 311 of the device to use individual voltage output terminals 312, 313, 314, and 315. . The voltage output terminal 316 differentially amplifies the sum of the upper light receiving surfaces 308 and 309 and the lower light receiving surfaces 310 and 311 through the differential amplifier, and outputs the voltage output terminal 317 to the left through the differential amplifier. The sum of the light receiving surfaces 308 and 310 and the right light receiving surfaces 309 and 311 are differentially amplified and output.

In terms of distance, the light is better through the light emitting unit lens 15 in the light emitting element 11, and the light reflected on the surface of the reflecting member 20 is received through the light receiving unit lens 16. As the focal point is formed on the 308, 309, 310, and 311, and the distance of the reflective member 20 increases, the focal point moves in a direction adjacent to the light emitting element 11, that is, the light receiving surfaces 308 and 310. As a result, the voltage output terminals 312, 313, 313, and 314 of the photo-voltage device receive light from the photo-voltage devices 308 and 310 adjacent to the light emitting device 11 when the distance of the reflective member 20 increases. The output increases. The position of light incident on the light receiving surfaces 308, 309, 310, and 311 may be predicted using this. That is, the incident light on the distance position is able to be measured by dividing the sum output of the other light-receiving surface (309, 311) at the output the sum of the light-emitting element-side light-receiving surface (308, 310) to a full output. In addition, when the reflective member 20 moves at the same distance, the position of the light may move up and down, and in this case, the up and down incident position of the light may be the lower light receiving surface 310, 311 at the sum of the outputs of the upper light receiving surface 308, 309. The difference between the sum of the output and the total output can be measured. Accordingly, the distance and the left and right movement of the reflective member 20 can be measured.

In another embodiment of the present invention, in order to output the output value as a digital value so that the distance to the reflecting member can be measured, the output of the differential amplifier is inverted at the time when the distribution of light changes ("0" in the formula). Thus, a certain distance can be detected by the change in the output. Accordingly, four types of sections (non-detection, long distance, medium distance, and short distance) can be output according to the arrangement of the light receiving surface as shown in FIG. 9. When the output of the detection light receiving surfaces 319 and 320 is higher than the reference light receiving surface 318 on the light emitting element 11 side, the image is reversed. When the light is not on the light receiving surface, the phases of the output terminals 321 and 322 through the differential amplifier are the same, In the case of a long distance, when the light of the detection light receiving surface 320 comes in than the reference light receiving surface 318, the image of the output terminal 322 is changed, and when the detector enters the medium distance, the detection light receiving surfaces 319 and 320 are larger than the reference light receiving surface 318. Because of this high, the output stages 321 and 322 output images opposite to those in the undetected state, and when the detector is located at a short distance, an image of light is formed on one detection light receiving surface 319 so that only one output terminal 321 is undetected. The phase opposite to that of the state is output.

Claims (11)

A light emitting device emitting light to the object for distance measurement;
A lens unit formed between the light emitting element and the optical path of the object;
And a light receiving unit in which a plurality of light-voltage conversion elements for receiving light from the object are arranged. 2. The module for distance measurement sensors according to claim 1, wherein the photo-voltage converter is arranged by connecting two or more photo-voltage converters in a direction away from a position adjacent to the light emitting device. The distance measuring module of claim 1, wherein the photo-voltage conversion device is a rectangular type of devices connected to each other so that two or more devices are arranged in two or more columns. The distance measuring sensor according to claim 1, wherein a lens for condensing the reflected light reflected from the object on the surface of the light-voltage conversion element is formed in an optical path between the object and the light-voltage conversion element. module. The distance measuring module according to claim 1, wherein the distance measuring module is focused on a conversion element located adjacent to the light emitting device as the distance from the target object increases. A printed circuit board or a substrate made of a lead frame;
A light emitting unit including a light emitting diode mounted on one side of the substrate;
A light emitting side condenser lens for condensing the emitted light onto an object;
A light-receiving-side condenser lens for condensing the light reflected from the object to the light-receiving unit;
A light receiving unit including a plurality of light-voltage conversion elements connected in parallel to receive light from the light receiving side light collecting lens; And
And a separation part for optically separating the light emitting part and the light receiving part. The module for distance measuring sensors according to claim 6, wherein the light emitting diode is an infrared diode, and the separation part is a black injection molded product having a slit in which a lens can be installed. 8. The module for distance measuring sensors according to claim 6 or 7, wherein the light receiving unit substrate is provided with a differentially amplified voltage output terminal. A printed circuit board or a substrate made of a lead frame;
A light emitting device mounted on the substrate and emitting light to an object for distance measurement;
A plurality of light receiving elements mounted on the substrate to receive the reflected light reflected from the target object is provided, wherein the light receiving element is a distance measuring module, characterized in that the output of the light receiving element is changed in accordance with the distance to the target object . 10. The distance measuring module of claim 9, wherein, as the object object distance increases, the reflecting area of the reflected light moves from a light receiving element located far from the light emitting element to a light receiving element located adjacent to the light emitting element. The distance measuring module according to claim 9, wherein the distance of the object is measured by dividing the difference between the output of the light receiving surface adjacent to the light emitting element and the output of the other light receiving surface by the total output.

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