KR102391022B1 - Light emitting module - Google Patents

Abstract

An optical output module is disclosed. According to an aspect of the present invention, an optical output module includes: a light source; a light condensing unit for condensing the light emitted from the light source; an optical guide unit having a plurality of waveguides formed therein and moving the light collected through the light collecting unit through each waveguide; and a lens unit for projecting the light emitted from the light guide unit to a set area, wherein the light guide unit includes: a branching unit for branching at least one of the plurality of waveguides into a plurality; a coupling part formed by approaching each waveguide branched by the branching part at a set interval; and a channel selection unit arranged at different intervals from the optical exit of the reference waveguide and selecting at least one optical exit with respect to the optical exit respectively connected to the waveguide coupled by the coupling unit.

Description

Light output module {LIGHT EMITTING MODULE}

The present invention relates to an optical output module, and more particularly, to an optical output module capable of calculating an accurate distance to an object by dynamically forming various interference patterns by multiple spatial frequencies.

Recently, in the imaging of objects such as humans and other objects, attempts are being made to reflect the shape of the actual object and implement it as a three-dimensional image. As a method of acquiring 3D depth information, there are a stereo vision method, a time of flight (TOF) method, a structured light method, and the like.

The stereo vision method acquires images of both eyes of the left and right eyes, finds a matching point between the two images, estimates disparity, and then acquires depth information.

The TOF method is a technology that measures the distance of an object using signals such as near-infrared rays, ultrasonic waves, and lasers. TOF measures the depth of the object by measuring the flight time when signals such as near-infrared rays, ultrasonic waves, and lasers fly, hit an object, and then return.

The structured light method calculates 3D depth information by using a method of converting one camera in the stereo vision system into an illumination system that projects a known shape. In this case, the structured light method acquires depth information in the entire area through which the structured light is scanned by scanning a pattern to the object and observing a geometric change.

That is, structured light refers to light having a specific pattern, and there are various techniques for configuring the pattern of structured light. A well-known method is to generate a gray code by combining multiple binary images. Phase shifting generates a sine or cosine function to change the phase and generates a special code by combining the obtained images. (phase shifting) There is a method.

On the other hand, the conventional general structured light system using the phase shifting method forms one spatial frequency by applying the PLC (Planar Light-wave Circuit) technology.

However, since there is a limit to calculating an accurate distance to an object with only one spatial frequency, the conventional structured light system has a problem in that it is difficult to apply to various products requiring more accurate distance calculation.

The present invention has been devised to solve the above problems, and an object of the present invention is to provide an optical output module capable of calculating an accurate distance to an object by dynamically forming various interference patterns by multiple spatial frequencies.

An optical output module capable of forming a dynamic interference pattern according to an aspect of the present invention for achieving the above object includes: a light source; a light condensing unit for condensing the light emitted from the light source; an optical guide unit having a plurality of waveguides formed therein and moving the light collected through the light collecting unit through each waveguide; and a lens unit for projecting the light emitted from the light guide unit to a set area, wherein the light guide unit includes: a branching unit for branching at least one of the plurality of waveguides into a plurality; a coupling part formed by approaching each waveguide branched by the branching part at a set interval; and a channel selection unit arranged at different intervals from the optical exit of the reference waveguide and selecting at least one optical exit with respect to the optical exit respectively connected to the waveguide coupled by the coupling unit.

Here, the optical guide unit may further include a heater installed on at least one of the reference waveguide and the waveguides branched by the branching unit.

In addition, the light guide unit may change the refractive index of light moving through the waveguide by adjusting the heater installed on the upper part of the reference waveguide in a set stage step by step with respect to the on/off of the heater installed on the upper part of the waveguide branched by the branching part. .

In addition, in the light guide unit, a plurality of branch portions are provided, one coupling portion and one heater are installed corresponding to each branch portion, and the channel selector may select different light outlets corresponding to each coupling portion. .

In addition, the optical guide unit includes at least two or more coupling units in which a waveguide extending from the input terminal is branched into at least three or more waveguides by the branching part, and one heater and a heater are shared in correspondence to the branching part, and the channel selection unit is each It is also possible to select different light outlets corresponding to the coupling portion of the .

In addition, the optical guide part consists of a plurality of layers, and the optical guide part of each layer connects the waveguides coupled by the respective coupling parts to the optical exits in different directions, shares the heater, and is stacked vertically, channel selection The unit can select each light exit.

The optical output module capable of forming a dynamic interference pattern according to the present invention can form an interference pattern in which several spatial frequencies overlap, as well as an interference pattern in which several spatial frequencies appear alternately by switching the exit channel of the waveguide. In this way, it is possible to calculate an accurate distance to an object using various interference patterns formed by multiple spatial frequencies.

1 is a diagram schematically illustrating a side view of an optical output module according to an embodiment of the present invention.
FIG. 2 is a diagram schematically illustrating an example of the light guide unit shown in FIG. 1 .
3 is a view showing an example of controlling each heater of the light guide unit shown in FIG. 2 , wherein (a) is a diagram illustrating temperature control of a reference heater, (b) is a diagram illustrating temperature control of branch heaters .
4 and 5 are diagrams illustrating an example in which a phase shift of an interference pattern is generated by controlling the temperature of a reference heater, and various spatial frequencies are alternately displayed by switching channels of a coupled waveguide.
FIG. 6 is a view schematically illustrating another example of the light guide unit shown in FIG. 1 .
7 is a view showing a control example of each heater of the light guide unit shown in FIG. 6, (a) is a diagram illustrating the temperature control of the reference heater, (b) is a diagram illustrating the temperature control of the first branch heater, , (c) is a diagram illustrating temperature control of the second branch heater.
FIG. 8 is a view schematically illustrating another example of the light guide unit shown in FIG. 1 .
9 is a view schematically showing another example of the light guide unit shown in FIG. 1 , (a) is an upper light guide unit, (b) is a lower light guide unit, (c) is a shared heater It is a view showing an example in which the optical guide part of the upper layer and the optical guide part of the lower layer are stacked to do so.

Hereinafter, some embodiments of the present invention will be described with reference to exemplary drawings. In describing the reference numerals for the components of each drawing, the same components are denoted by the same reference numerals as much as possible even if they are displayed on different drawings. In addition, in describing the embodiment of the present invention, if it is determined that a detailed description of a related known configuration or function interferes with the understanding of the embodiment of the present invention, the detailed description thereof will be omitted.

In addition, in describing the components of the embodiment of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, or order of the elements are not limited by the terms. When a component is described as being “connected”, “coupled” or “connected” to another component, the component may be directly connected, coupled, or connected to the other component, but the component and the other component It should be understood that another element may be “connected”, “coupled” or “connected” between elements.

1 is a diagram schematically illustrating a side view of an optical output module according to an embodiment of the present invention.

Referring to FIG. 1 , the light output module according to an embodiment of the present invention includes a light source 100 , a light collecting unit 200 , a light guide unit 300 , and a lens unit 400 .

The light source 100 emits light. In this case, the light source 100 preferably emits coherent light. Here, the coherent light refers to light having a single frequency spectrum, having the same phase, and forming a uniform sine wave.

In order to observe light interference, light having the same wavelength and a constant phase difference with respect to time must meet. A light source satisfying such a condition is called a coherent light source, and a laser is used as a representative coherent light source.

In order to realize the coherent light source, the light source 100 may be implemented as a laser diode (LD), and in particular, an edge emitting laser (EEL) or a vertical cavity surface emitting laser (VCSEL) diode may be used. However, the type of the light source 100 is not limited to the described description, and it goes without saying that various types of light sources may be used if coherent light is emitted.

The light condensing unit 200 condenses the light emitted from the light source 100 , and allows the condensed light to be input to the light guide unit 300 . Since the laser diode emits light with an angle of view of 8 to 40 degrees, the light collecting unit 200 condenses the light emitted by the light source 100 so that it is input to the input terminal 310 of the light guide unit 300 . In this case, the light collecting unit 200 may be implemented as a lens.

Here, the light collecting unit 200 may be a GRIN Lens, Lensed Fiber, Aspheric Lens, etc., but the type of lens is not limited to the description, and the light guide unit 300 ), of course, various types of lenses can be used.

In the light guide unit 300 , a plurality of waveguides 320 extending from the input terminal 310 are formed, and the light collected through the light collecting unit 200 moves through each waveguide 320 .

The heater 330 may be installed above at least one waveguide of the light guide unit 300 and applies heat to the corresponding waveguide. When heat is applied to the corresponding waveguide through the heater 330, the refractive index of the light wave traveling along the waveguide is changed, and the phase pattern of the output light can be changed using this characteristic. In this case, the heater 330 may variously change the phase pattern of light by adjusting the temperature of the heat applied to the waveguide in stages. In addition, the heater 330 may be installed to correspond to each waveguide. In this case, the heater 330 may change the phase pattern of light in various ways by adjusting the temperature applied to each waveguide differently. .

The lens unit 400 transmits the light emitted from the light guide unit 300 and projects it to a set area. In this case, the lens unit 400 may receive the light refracted by the refraction unit 340 of the light guide unit 300 , and may adjust the diffraction angle of the input light to project it to a set area.

FIG. 2 is a diagram schematically illustrating an example of the optical guide unit shown in FIG. 1 , and is a diagram illustrating a structure of a waveguide formed in the optical guide unit 300 .

Referring to FIG. 2 , the light guide unit 300 may include a branching unit 322 , a coupling unit 324 , and a channel selection unit 326 .

The branching unit 322 may branch at least one of the plurality of waveguides 320 extending from the input terminal 310 into two or more waveguides. 2 illustrates a case in which the branching unit 322 branches the waveguide 320 into two waveguides. In this case, the waveguides branched by the branching part 322 extend to a set length. Here, the branching part 322 serves to make the branched waveguides have different lengths from that of the waveguides extending from the input terminal 310 . In FIG. 2 , the branching part 322 is exaggerated to branch the waveguide 320 at a wide angle for better understanding, but the actually used branching angle may be 1 degree or less.

Polarized light passing through the branched waveguide must have a polarization-maintaining characteristic. To this end, in the embodiment of the present invention, each waveguide branched by the branching part 322 approaches each other at a set interval to form the coupling part 324 , so that the light wave travels along each waveguide of the coupling part 324 . During this time, directional coupling occurs between the waves.

In this case, the branching part 322 and the coupling part 324 may have an inverted rib structure that is asymmetrical in vertical and horizontal directions.

Meanwhile, in the optical guide unit 300 , a plurality of exits are disposed at different intervals with respect to the exit of the reference waveguide, and respective optical exits at different intervals with respect to the reference waveguide are coupled by the coupling unit 326 to the waveguide. are connected to each Here, the reference waveguide is an unbranched waveguide among a plurality of waveguides extending from the input terminal 310 and refers to a specific waveguide designated as a reference. For example, as shown in FIG. 2 , two light outlets Ch1 and Ch2 may be arranged at different intervals with respect to the light outlet of the reference waveguide Ref., and the respective light outlets Ch1 and Ch2 may be respectively connected to the waveguide coupled by the coupling unit 324 . In this case, it is preferable that the intervals of the respective light exits are formed to be the same, but is not necessarily limited thereto.

The channel selector 326 may select at least one light outlet for each of the light outlets Ch1 and Ch2 connected to the waveguide coupled by the coupling unit 326 . To this end, the channel selector 326 may be implemented as an active element that switches a channel of light output from the coupling unit 326 .

If the path difference of two light emitted from each waveguide is an even multiple of half wavelength, constructive interference (bright fringe) occurs because the two waves overlap each other. . In this case, if the unit interval of the interference pattern is Δy, then L is the distance from the waveguide exit to the object, λ is the wavelength, and d is the waveguide interval.

The channel selection unit 326 changes the unit interval Δy of the interference pattern by adjusting the waveguide interval d by switching the channel of the light output from the coupling unit 326 .

Meanwhile, the heater 330 includes a first heater 330 - 1 installed above the reference waveguide 320 and a second heater 330 - 2 installed above any one of the waveguides branched by the branching part 322 . ) is included. At this time, the second heater 330-2 controls ON or OFF as shown in FIG. 3B, and the first heater 330-1 is shown in FIG. 3A. As shown, the temperature can be controlled by adjusting the temperature in each set step corresponding to the on or off of the second heater 330 - 2 , respectively. Here, the second heater 330-2 has been illustrated and described as controlling on/off for better understanding, but the second heater 330-2 is operated in both stages of the temperature of the first stage and the temperature of the second stage. The temperature is controlled, and the first heater 330 - 1 may control the temperature by adjusting the temperature in a plurality of stages corresponding to each stage of the second heater 330 - 2 . In addition, although the first heater 330 - 1 is illustrated as controlling the temperature in four stages corresponding to each stage of the second heater 330 - 2 , the number of each stage of the first heater 330 - 1 is shown. is not limited thereto, and it is of course possible to control the temperature in a number of steps.

4 and 5 are diagrams illustrating an example in which a phase shift of an interference pattern is generated by controlling the temperature of a reference heater, and various spatial frequencies are alternately displayed by switching channels of a coupled waveguide.

4 and 5 , with respect to the light guide unit 300 having the structure as shown in FIG. 2 , channel 2 is selected when the heater 330 is not operated, and channel 1 is selected when the heater 330 is operated. As a result of outputting light, the interference pattern was changed from the shape of FIG. 4 to the shape of FIG. 5 . In addition, as the temperature of the reference heater was adjusted in various stages, the interference pattern was variously modified, and when each channel was not switched, an interference pattern in which several spatial frequencies overlapped occurred.

Accordingly, the light output module according to the present invention can be used as a structured light pattern by variously changing the phase of the interference fringe by the waveguide without physically moving the light source.

In addition, the optical output module according to the present invention may form an interference pattern in which various spatial frequencies appear alternately by switching the exit channel of the waveguide.

In addition, the optical output module according to the present invention can calculate an accurate distance to an object by using various interference patterns formed by multiple spatial frequencies.

FIG. 6 is a view schematically illustrating another example of the light guide unit shown in FIG. 1 .

Referring to FIG. 6 , the light guide unit 300 includes two or more branching parts 322 , and one coupling part 324 and one heater 330-2 corresponding to each branching part 322 . or 330-3) is installed. In addition, the channel selector 326 may select different light outlets corresponding to the respective coupling units 324 . In FIG. 6 , two branch portions 322 are provided in the optical guide 300 , and a first heater 330 - 1 and a second heater ( 330 - 1 ) and a second heater ( 330 - 1 ) respectively correspond to the reference waveguide 320 and each branch portion 322 . 330-2) and a third heater 330-3 are shown to be installed.

At this time, the temperature of the second heater 330-2 and the third heater 330-3 may be controlled by turning it off or on so as to be opposite to each other, as shown in (b) and (c) of FIG. 7 , The first heater 330 - 1 of the reference waveguide may control the temperature in a plurality of steps in response to each on/off control of the second heater 330 - 2 and the third heater 330 - 3 .

FIG. 8 is a view schematically illustrating another example of the light guide unit shown in FIG. 1 .

Referring to FIG. 8 , the waveguide 320 extending from the input terminal 310 is branched into at least three waveguides by the branching part 322 , and corresponding to the branching part 322 , one heater 330-2 and Two or more coupling parts 324 are installed. In addition, the channel selector 326 may select different light outlets corresponding to the respective coupling units 324 . In FIG. 8 , one branching part 322 is provided in the optical guide 300 , and the branching part 322 branches the waveguide into three waveguides, and corresponds to the reference waveguide 320 and the branching part 322 , respectively. A first heater 330 - 1 and a second heater 330 - 2 are installed, and two coupling units 324 each share a second heater 330 - 2 with a branched waveguide and another branched waveguide. The waveguide is shown as coupling.

9 is a view schematically showing another example of the light guide unit shown in FIG. 1 , (a) is an upper light guide unit, (b) is a lower light guide unit, (c) is a shared heater It is a view showing an example in which the optical guide part of the upper layer and the optical guide part of the lower layer are stacked to do so.

As such, the light guide unit 300 may be formed of a plurality of layers. In this case, in the optical guide part 300 of each layer, the waveguides coupled by the respective coupling parts 324 are connected to the optical exits in different directions, and they are stacked vertically by sharing the heater 330 . In this case, the channel selector may switch the light output by selecting each light outlet.

Although the embodiments according to the present invention have been described above, these are merely exemplary, and those of ordinary skill in the art will understand that various modifications and equivalent ranges of embodiments are possible therefrom. Accordingly, the protection scope of the present invention should be defined by the following claims as well as their equivalents.

100: light source 200: light collecting unit
300: optical guide unit 310: input terminal
320: waveguide 322: bifurcation
324: coupling unit 326: channel selection unit
330: heater 400: lens unit

Claims (6)

light source;
a light condensing unit for condensing the light emitted from the light source;
an optical guide unit having a plurality of waveguides formed therein and moving the light collected through the light collecting unit through each waveguide; and
and a lens unit for projecting the light emitted from the light guide unit to a set area,
The plurality of waveguides respectively extend from one input end and are connected to any one of the plurality of optical outlets;
The plurality of waveguides extend from the input terminal and include a reference waveguide connected to any one of the plurality of optical outlets without branching;
The light guide unit,
a branching unit for branching a plurality of waveguides other than the reference waveguide among the plurality of waveguides;
a coupling part formed by approaching each waveguide branched by the branching part at a set interval;
a channel selector arranged at different intervals from the optical exit of the reference waveguide and selecting at least one optical exit from the optical exits respectively connected to the waveguides coupled by the coupling part; and
a heater installed on at least one of the reference waveguide and the waveguides branched by the branching part;
The light guide unit,
A plurality of the branch portions are provided, one coupling portion and one heater are installed corresponding to each of the branch portions, and the channel selector selects different light outlets corresponding to the respective coupling portions. output module. delete According to claim 1,
The light guide unit,
An optical output module for changing the phase pattern of light moving in the waveguide by adjusting the heater installed on the upper part of the reference waveguide in a set step step with respect to the on/off of the heater installed on the upper part of the waveguide branched by the branching part. delete According to claim 1,
The light guide unit,
A waveguide extending from an input terminal is branched into at least three or more waveguides by the branching part, and corresponding to the branching part, one heater and at least two or more coupling parts sharing the heater are provided, and the channel selection part is each An optical output module for selecting different optical outlets corresponding to the coupling part of the. According to claim 1,
The optical guide part is made of a plurality of layers, and the optical guide part of each layer is stacked vertically by sharing the heater, wherein the waveguides coupled by the respective coupling parts are connected to each other through optical exits, The channel selector selects each optical outlet, the optical output module.

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