KR20200023843A - A vertical-cavity surface-emitting laser package and light emitting device including the same - Google Patents

Abstract

According to an embodiment of the present invention, provided are a vertical-cavity surface-emitting laser (VCSEL) package and a light emitting device including the same. According to an embodiment of the present invention, the VCSEL package may comprise: a housing including a cavity; a surface emitting laser element disposed in the cavity; and a diffusion portion disposed on the housing. The diffusion portion may include a polymer layer, and a glass layer disposed on the polymer layer. The polymer layer may include a first polymer layer that vertically overlaps the surface emitting laser element and a second polymer layer that does not vertically overlap the surface emitting laser element. The thickness of the first polymer layer may be thinner than the thickness of the second polymer layer.

Description

Surface-emitting laser package and light emitting device including the same {A VERTICAL-CAVITY SURFACE-EMITTING LASER PACKAGE AND LIGHT EMITTING DEVICE INCLUDING THE SAME}

Embodiments relate to a surface emitting laser package and a light emitting device including the same.

A semiconductor device including a compound such as GaAs or AlGaAs may emit light of various wavelength bands by using a wide and easy-to-adjust band gap energy, and thus may be variously used as a light emitting device, a light receiving device, and various diodes.

In particular, light emitting devices such as light emitting diodes and laser diodes using group 3-5 or group 6 compound semiconductor materials are developed using thin film growth technology and device materials, such as red, green, blue and ultraviolet light. Various colors can be realized, and efficient white light can be realized by using fluorescent materials or combining colors.Low power consumption, semi-permanent life, fast response speed, safety, It has the advantages of environmental friendliness.

In addition, when a light receiving device such as a photodetector or a solar cell is manufactured by using a group 3-5 or group 6 compound semiconductor material, the development of device materials absorbs light in various wavelength bands and generates a photocurrent to generate a light current. It can receive light in various wavelength bands up to the wavelength band. In addition, semiconductor devices have the advantages of fast response speed, safety, environmental friendliness, and easy control of device materials, so that they can be easily adopted in power control or microwave circuits or communication modules.

Therefore, the semiconductor device may replace a transmission / reception module of an optical communication system, a light emitting unit that replaces a cold cathode fluorescent lamp (CCFL) constituting a backlight of a liquid crystal display (LCD), a fluorescent lamp, or an incandescent bulb. Applications are expanding to lighting devices such as white light emitting diodes, automotive headlights, traffic lights or sensors to detect gas or fire.

In addition, the semiconductor device may be extended to high frequency application circuits, other power control devices, and communication modules. For example, there is a surface-emitting laser (VCSEL) device as a semiconductor device. Surface emitting laser devices are used in optical communication, optical parallel processing, optical connection, and the like. On the other hand, the laser diode used in such a communication module is designed to be easy to operate at a low current.

Surface-emitting laser devices are being developed for communication and sensors. The surface emitting laser device for communication is applied to an optical communication system.

The surface emitting laser device for a sensor is applied to a 3D sensing camera that recognizes a human face. For example, a 3D sensing camera is a camera capable of capturing depth information of an object, and has recently been in the spotlight in conjunction with augmented reality.

On the other hand, a depth sensor of the camera module is equipped with a separate sensor, it is divided into two types of structured light (SL) method and ToF (Time of Flight) method.

In the structured light (SL) method, a laser of a specific pattern is emitted to a subject, the depth of the pattern is analyzed according to the shape of the subject surface, the depth is calculated, and then synthesized with the photograph taken by the image sensor to obtain a 3D photographing result.

In contrast, the ToF method calculates the depth by measuring the time when the laser is reflected back to the subject, and then synthesizes it with the photograph taken by the image sensor to obtain a 3D photographing result.

As a result, the SL method has an advantage in mass production in that the laser has to be positioned very accurately, whereas the ToF technology relies on an improved image sensor, and one or both methods can be adopted in one mobile phone. It may be.

For example, a 3D camera called True Depth can be implemented in the SL method on the front of the mobile phone and can be applied in the ToF method on the back.

The surface emitting laser device may be commercialized in a surface emitting laser package. In a conventional surface emitting laser package, a diffuser is disposed on the surface emitting laser device to diffuse the laser beam of the surface emitting laser device. It is fixed by the adhesive member.

However, even if the diffuser is fixed by the adhesive member, a problem arises in that the diffuser is detached by an impact. When the diffusion is detached as described above, the laser beam emitted from the surface emitting laser device disposed below the diffusion is exposed as it is. When the surface emitting laser package is applied to the face recognition field, there is a risk of eye safety because the laser beam exposed by the detachment of the diffuser is transmitted to the eyes of the user and thus blinded.

In particular, in the prior art, the diffuser includes a glass layer and a polymer layer, and the thermal shock or heat cycle test is performed as the glass layer and the polymer layer have different coefficients of thermal expansion. There is a problem that peeling occurs in a reliability test such as a thermal cycle test, and the diffusion peeling problem causes a technical problem that cannot guarantee eye safety.

Embodiments provide a surface emitting laser package having excellent reliability and a light emitting device including the same.

The technical problem of the embodiments is not limited to the contents described in this item, but includes those grasped through the description of the invention.

The surface emitting laser package according to the embodiment may include a housing including a cavity, a surface emitting laser element disposed in the cavity, and a diffusion part disposed on the housing.

The diffusion part may include a polymer layer and a glass layer disposed on the polymer layer.

The polymer layer may include a first polymer layer vertically overlapping the surface emitting laser device, and a second polymer layer not vertically overlapping the surface emitting laser device.

The thickness T2a of the first polymer layer may be thinner than the thickness T2b of the second polymer layer.

The thickness T2b ratio T2b / T1 of the second polymer layer 146b to the first thickness T1 of the glass layer 141 may range from 0.12 to 3.0.

The embodiment may further include an adhesive member 155 between the housing and the polymer layer.

The coefficient of thermal expansion of the adhesive member 155 may be in the range of 1 to 2 times the coefficient of thermal expansion of the polymer layer 146.

The surface emitting laser package according to the embodiment includes a housing including a cavity, a surface emitting laser element disposed in the cavity, and a diffuser disposed on the housing, wherein the diffuser is formed on a housing on the surface emitting laser element. It may include a polymer layer disposed and a glass layer disposed on the polymer layer.

A ratio T2 / T1 of the second thickness T2 of the polymer layer to the first thickness T1 of the glass layer may range from 0.12 to 3.0.

The embodiment may further include an adhesive member between the housing and the polymer layer.

The thermal expansion coefficient of the adhesive member 155 may be in the range of 1 to 2 times the thermal expansion coefficient of the polymer layer.

The light emitting device according to the embodiment may include the surface light emitting laser package.

According to the embodiment, there is a technical effect of preventing peeling of the diffusion part and providing a surface emitting laser package having excellent reliability and a light emitting device including the same.

For example, according to the exemplary embodiment, the relative thickness is controlled by controlling the ratio T2 / T1 of the second thickness T2 of the polymer layer 145 which is the second layer to the first thickness T1 of the glass layer 141 which is the first layer. By controlling the relative stress low, even if the glass layer 141 and the polymer layer 145 have different coefficients of thermal expansion, they are excellent in reliability tests such as thermal shock or thermal cycle test. There is a technical effect that can be shown.

In an embodiment, the first thickness T2a of the first polymer layer 146a is controlled to be thinner than the second thickness T2b of the second polymer layer 146b to vertically overlap the surface light emitting laser device 201. The optical property may be improved by increasing the light transmittance in the first polymer layer 146a. At the same time, the second thickness T2b of the second polymer layer 146b not vertically overlapping the surface emitting laser device 201 is thicker than the first thickness T2a of the first polymer layer 146a. At the same time as controlling the thickness ratio (T2b / T1) to the first thickness (T1) of the glass layer 141 in the range of 0.12 to 3.0 has a complex technical effect excellent in reliability that is robust to thermal stress.

Further, according to the embodiment, the thermal expansion coefficient of the adhesive member 155 is controlled to be in the range of 1 to 2 times the thermal expansion coefficient of the polymer layer 146 to minimize the thermal expansion coefficient between the polymer layer 146 and the adhesive member 155. There is a technical effect that can greatly improve the reliability.

The technical effects of the embodiments are not limited to those described in this section, but include those grasped through the description of the invention.

1 is a cross-sectional view of a surface emitting laser package according to a first embodiment.
2 is an enlarged view of a first region in the surface emitting laser package according to the first embodiment;
Figure 3 is a photograph of the diffusion in the surface emitting laser package according to the first embodiment.
4 is relative stress data according to the relative thickness of the glass layer and the polymer layer in the diffusion portion of the surface-emitting laser package according to the first embodiment.
Figure 5 is a photograph of the reliability test results in the surface-emitting laser package according to the comparative example and the embodiment.
6 is a cross-sectional view of the surface emitting laser package according to the second embodiment.
7 is an enlarged view of a second region in the surface emitting laser package according to the second embodiment;
FIG. 8 is light absorption data according to thickness in a polymer layer of a diffusion part in the surface emitting laser package according to the second embodiment. FIG.
9 is a photograph of the reliability test results in the surface-emitting laser package according to Comparative Example 2, Comparative Example 3 and the third embodiment.
10 is a plan view of a surface emitting laser device according to an embodiment.
FIG. 11 is an enlarged view of one region C1 of the surface emitting laser device according to the embodiment shown in FIG. 10.
12 is a cross-sectional view taken along line A1-A2 of the surface emitting laser device according to the embodiment shown in FIG.
13 is another cross-sectional view of the surface emitting laser device according to the embodiment.
14 is a perspective view of a mobile terminal to which the surface emitting laser device is applied according to the embodiment;

DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

In the description of the embodiments, when described as being formed on the "on or under" of each element, the on or under is It includes both the two elements are in direct contact with each other (directly) or one or more other elements are formed indirectly between the two (element). In addition, when expressed as "on" or "under", it may include the meaning of the downward direction as well as the upward direction based on one element.

(First embodiment)

FIG. 1 is a cross-sectional view illustrating a surface light emitting laser package 100 according to a first embodiment, and FIG. 2 is an enlarged view of a first region D1 in a surface light emitting laser package according to a first embodiment. 140 is an enlarged view.

Referring to FIG. 1, the surface emitting laser package 100 according to the first embodiment may include a housing 110, a surface emitting laser device 201, and a diffusion unit 140. For example, the surface emitting laser package 100 according to the first embodiment may include a housing 110 having a cavity C, a surface emitting laser element 201 and the housing disposed in the cavity C. The diffusion part 140 may be disposed on the 110.

Hereinafter, the surface light emitting laser package 100 according to the first embodiment will be described with reference to FIGS. 1 to 5.

In the surface emitting laser package 100 according to the embodiment, the housing 110 may support the surface emitting laser device 201 and the diffuser 140 disposed thereon. The housing 130, the surface emitting laser device 201, and the diffuser 140 may be modules modularized by a packaging process. One or more such modules may be mounted on a circuit board (not shown).

The housing 110 of the embodiment may include a material having excellent support strength, heat dissipation, insulation, and the like. The housing 110 may include a material having high thermal conductivity. In addition, the housing 110 may be made of a material having good heat dissipation characteristics so as to efficiently discharge heat generated from the surface emitting laser device 201 to the outside.

In addition, the housing 110 may include an insulating material. For example, the housing 110 may include a ceramic material. The housing 110 may include a low temperature co-fired ceramic (LTCC) or a high temperature co-fired ceramic (HTCC) that is co-fired. In addition, the housing 110 may be provided of a silicone resin, an epoxy resin, a thermosetting resin including a plastic material, or a high heat resistant material.

In addition, the housing 110 may include a metal compound. The housing 110 may include a metal oxide having a thermal conductivity of 140 W / mK or more. For example, the housing 110 may include aluminum nitride (AlN) or alumina (Al ₂ O ₃ ). In addition, the housing 110 may include a conductive material. When the housing 110 is made of a conductive material, such as a metal, between the housing 110 and the surface emitting laser element 201 or between the housing 110 and the first to sixth electrode portions 181 to 186 described later. An insulation member for electrical insulation can be provided.

The housing 110 may have a square shape when viewed from above, but is not limited thereto.

With continued reference to FIG. 1, the housing 110 of an embodiment may include a single or a plurality of bodies. For example, the housing 110 may include a first body 110a, a second body 110b, and a third body 110c. The second body 110b may be disposed on the first body 110a, and the third body 110c may be disposed on the second body 110b.

The first body 110a to the third body 110c may be made of the same material and integrally formed. Meanwhile, the first to third bodies 110a to 110c may be formed of different materials and formed by separate processes. For example, the second to third bodies 110b to 110c are made of the same material and are integrally formed. The first body 110a is made of a different material from the second to third bodies 110b to 110c and is separate. It can be formed by the process. In this case, the lower surfaces of the second to third bodies 110b to 110c integrally formed and the upper surface of the first body 110a may be adhered to each other by an adhesive member (not shown). For example, the adhesive member may include at least one of an organic material, an epoxy resin, or a silicone resin.

Next, the surface emitting laser package 100 according to the embodiment may include a first electrode portion 181 and a second electrode portion 182. The first electrode part 181 and the second electrode part 182 may be disposed in the housing 110. In detail, the first electrode part 181 and the second electrode part 182 may be spaced apart from each other on the upper surface of the first body 110a.

In an embodiment, the surface emitting laser device 201 may be disposed on the first electrode part 181. The surface emitting laser device 201 may be disposed on a portion of the first electrode part 181. The size of the first electrode unit 181 may be larger than that of the surface emitting laser device 201. For example, the surface emitting laser device 201 may have a square when viewed from above, but is not limited thereto.

The surface emitting laser device 201 may be electrically connected to the second electrode unit 182 by a predetermined wire 187.

In addition, the embodiment may include a third electrode portion 183 and a fourth electrode portion 184 spaced apart from the lower side of the first body (110a), and also penetrating the first body (110a) The fifth electrode part 185 and the sixth electrode part 186 may be included.

The fifth electrode part 185 may electrically connect the first electrode part 181 and the third electrode part 183, and the sixth electrode part 186 may be connected to the second electrode part 182. The fourth electrode unit 184 may be electrically connected to the fourth electrode unit 184.

In an embodiment, the housing 110 may include a seating part 110bt in which the diffusion part 140 is disposed. For example, a portion of the upper surface of the second body 110b may function as a seating portion 110bt.

The embodiment may include an adhesive member 155 disposed between the seating portion 110bt and the diffusion portion 140 of the housing 110. As the adhesive member 155, a material having excellent adhesion, moisture resistance, insulation, and support strength may be used. For example, the adhesive member 155 may include any one or more of an organic material, an epoxy resin, or a silicone resin.

As a result, the embodiment can provide a surface emitting laser package having excellent reliability by preventing detachment from the housing of the diffusion part and a light emitting device including the same.

Next, FIG. 2 is an enlarged view of the first region D1, for example, the diffusion unit 140, in the surface light emitting laser package 100 according to the first embodiment, and FIG. 3 is a surface light emitting laser according to the embodiment. Picture of the diffuser 140 in the package.

Referring to FIG. 2, in an embodiment, the diffusion part 140 has a glass layer 141 having a first thickness T1 and a polymer having a second thickness T2 and disposed on the glass layer 141. It may include layer 145. Although the polymer layer 145 is illustrated as being disposed under the glass layer 141 in FIG. 2, in the manufacturing process, the polymer layer 145 may be disposed above the glass layer 141 in a printing process. As shown in FIG. 2, the polymer layer 145 may include a pattern including a curved surface, which may be regular or irregular. In addition, the pattern may not be present in the contact portion of the adhesive member 155 to be described later, and may be formed in a relatively flat surface than the pattern.

As described above, in the prior art, the glass layer and the polymer layer constituting the diffuser have different coefficients of thermal expansion, and thus, in a reliability test such as thermal shock or thermal cycle test, There is a technical problem that the peeling of the diffusion occurs to ensure eye safety.

4 is a relative stress according to a thickness ratio (Relative Layer Thickness, T2 / T1) between the glass layer 141 and the polymer layer 145 which are adjacent layers in the diffusion 140 of the surface light emitting laser package according to the first embodiment. (Relative Stress, σ / σ ^T ) data.

The embodiment controls the ratio of thicknesses T2 / T1 of the glass layer 141, which is the first layer, and the polymer layer 145, which is the second layer, so as to have a different thermal expansion coefficient. There is a technical effect that can show excellent performance in reliability tests such as test).

For example, referring to FIG. 4, in the embodiment, the second thickness of the polymer layer 145 which is the second layer layer2 compared to the first thickness T1 of the glass layer 141 which is the first layer layer1. By controlling the ratio T2 / T1 to 0.12 to 3.0, which is the first range SE, the relative stress is controlled to be low in the range of −0.4 <σ / σ ^T <0.8 so that the glass layer 141 Although the polymer layer 145 has different coefficients of thermal expansion, there is a technical effect that can exhibit excellent performance in reliability tests such as thermal shock or thermal cycle test.

는 제2 층인 폴리머층(145)에서의 평균 스트레스(average stress in layer 2)이다. 도 4에서 Σ 값은 재료(material)에 따라 10, 1 또는 1/10 등의 값을 가질 수 있다.In this case, σ is a stress at top of layer 2 of the polymer layer 145 which is a second layer,

Is the average stress in layer 2 in the polymer layer 145 which is the second layer. In FIG. 4, the Σ value may have a value such as 10, 1, or 1/10 depending on the material.

Table 1 below shows the reliability test result data of the surface-emitting laser package (Experimental Example 1 to Experimental Example 3) according to Comparative Example 1 and Example (the reliability test is carried out with 5 samples each).

5 is a photograph of the reliability test results of the surface-emitting laser package according to Comparative Example 1 and Example. Specifically, Figure 5 (a) is a photograph of Comparative Example 1, Figure 5 (b) to Figure 5 (d) is a photograph of the first to third experimental examples.

Thickness of glass layer (T1) + thickness of polymer layer (T2) in mm
[T2 / T1] Start state 200 cycle 350 cycle 500 cycle 750 cycle Comparative Example 1 0.7+ 0.08
[8/70 = 0.1143] OK (5) NG (2) NG (5) NG (5) NG (5) Experimental Example 1 0.28 + 0.08
[8/28 = 0.286] OK (5) OK (5) OK (5) OK (5) OK (5) Experimental Example 2 0.2 + 0.1
[10/20 = 0.5] OK (5) OK (5) OK (5) OK (5) OK (5) Experimental Example 3 0.4 + 0.05
[5/40 = 0.125] OK (5) OK (5) OK (5) OK (5) OK (5)

Referring to Table 1 and FIG. 5, in Comparative Example 1, all the interfacial delaminations occurred from 200 cycles to 5 diffuser raw materials, but in Experimental Examples 1 to 3 according to the embodiment, no interfacial delamination occurred even up to 7500 cycles. Excellent reliability was shown.

According to the embodiment, the ratio T2 / T1 of the second thickness T2 of the polymer layer 145 which is the second layer to the first thickness T1 of the glass layer 141 which is the first layer is equal to the first range SE. By controlling the relative stress to 0.12 to 3.0 to lower the relative stress (Relative Stress), even if the glass layer 141 and the polymer layer 145 have different thermal expansion coefficients, such as thermal shock (Thermal Shock), heat cycle test (Thermal Cycle test) There is a technical effect that can show excellent performance in the same reliability test.

According to the embodiment, the ratio T2 / T1 of the second thickness T2 of the polymer layer 145 which is the second layer to the first thickness T1 of the glass layer 141 which is the first layer is set in the first range SE. Phosphorus 0.125 to 1.0 can be controlled.

According to the embodiment, the ratio T2 / T1 of the second thickness T2 of the polymer layer 145 which is the second layer to the first thickness T1 of the glass layer 141 which is the first layer is set in the first range SE. Phosphorus can be controlled from 0.125 to 0.5.

In addition, in the embodiment, the first thickness T1 of the glass layer 141 may be controlled to about 50 to 300 μm, and in the embodiment, the second thickness T2 of the polymer layer 145 is about 50 to 150 μm. Can be controlled.

According to an embodiment, the relative stress is controlled by controlling the ratio T2 / T1 of the second thickness T2 of the polymer layer 145 that is the second layer to the first thickness T1 of the glass layer 141 that is the first layer. By controlling the low), even if the glass layer 141 and the polymer layer 145 have different coefficients of thermal expansion, they can exhibit excellent performance in reliability tests such as thermal shock or thermal cycle test. It works.

(2nd Example)

Next, FIG. 6 is a cross-sectional view of the surface emitting laser package 102 according to the second embodiment, FIG. 7 is an enlarged view of the second region D2 in the surface emitting laser package according to the second embodiment, and FIG. 8. Is light absorption data according to the thickness of the polymer layer 146 of the diffusion part in the surface emitting laser package 102 according to the second embodiment.

The second embodiment may employ the technical features of the first embodiment, and will be described below mainly on the main features of the second embodiment.

The surface emitting laser package 102 according to the second embodiment includes a housing 110 including a cavity C, a surface emitting laser device 201 disposed in the cavity C, and the housing 110. The diffusion unit 140 may be disposed.

The diffusion unit 140 may include a polymer layer 146 disposed on the housing 110 on the surface light emitting laser device 201 and a glass layer 141 disposed on the polymer layer 146. can do.

Referring to FIG. 7, the polymer layer 146 may include a first polymer layer 146a vertically overlapping the surface emitting laser device 201 and a material not vertically overlapping the surface emitting laser device 201. And a second polymer layer 146b, and the first thickness T2a of the first polymer layer 146a may be thinner than the second thickness T2b of the second polymer layer 146b.

FIG. 8 is light transmission data according to the thickness z of the polymer layer 146 in the surface light emitting laser package 102 according to the second embodiment.

For example, in FIG. 8, the horizontal axis is the thickness z of the polymer layer 146, the vertical axis is light transmittance (I / I ₀ ) data, and α is (4πk / λ) as an absorption coefficient.

Referring to FIG. 8, it can be seen that the light transmittance (I / I ₀ ) of the vertical axis decreases exponentially as the light absorbency increases as the thickness z of the polymer layer 146 increases.

Referring back to FIG. 7, in the second embodiment, the first thickness T2a of the first polymer layer 146a is controlled to be thinner than the second thickness T2b of the second polymer layer 146b. The optical property may be improved by increasing the light transmittance in the first polymer layer 146a vertically overlapping the light emitting laser device 201. At the same time, the second thickness T2b of the second polymer layer 146b not vertically overlapping the surface emitting laser device 201 is thicker than the first thickness T2a of the first polymer layer 146a. At the same time as controlling the thickness ratio (T2b / T1`) of the glass layer 141 and the first thickness (T1) in the range of 0.12 to 3.0, there is a complex technical effect excellent in reliability that is robust to thermal stress.

In addition, referring to FIG. 7, in the second embodiment, the thermal expansion coefficient (unit, ppm / ° C.) of the adhesive member 155 is controlled to be in a range of 1 to 2 times of the thermal coefficient of thermal expansion of the polymer layer 146. The thermal expansion coefficient between the 146 and the adhesive member 155 may be minimized to significantly improve reliability.

For example, in the second embodiment, the coefficient of thermal expansion (unit, ppm / ° C) of the adhesive member 155 is controlled to about 70 to 80 (ppm / ° C), and the coefficient of thermal expansion of the polymer layer 146 is about 50 degrees. By controlling to ˜60, the thermal expansion coefficient of the adhesive member 155 is controlled to be in the range of 1 to 2 times the thermal expansion coefficient of the polymer layer 146 to minimize the thermal expansion coefficient between the polymer layer 146 and the adhesive member 155. The reliability can be greatly improved. In an embodiment, the material of the polymer layer may be a polyurethane acrylate series, but is not limited thereto.

Table 2 below shows the reliability test result data of the surface-emitting laser package according to Comparative Example 2, Comparative Example 3 and the second embodiment, Figure 9 is a surface-emitting laser according to Comparative Example 2, Comparative Example 3 and Example 2 Photo of reliability test results in the package.

Diffuser Bonding Start state 200 cycle 350 cycle 500 cycle 750 cycle 1000 cycle Comparative Example 2 same OK (5) OK (5) OK (5) OK (5) NG (5) NG (5) Comparative Example 3 same OK (5) OK (5) NG (5) NG (5) NG (5) NG (5) Experimental Example 4 same OK (5) OK (5) OK (5) OK (5) OK (5) OK (5)

Table 2 shows the reliability test result data of the surface-emitting laser package (Experimental Example 4) according to Comparative Example 2 and Comparative Example 3 and Example 2 (reliability test is carried out with 5 samples each).

9A is a photograph of Comparative Example 2, FIG. 9B is a photograph of Comparative Example 3, and FIG. 9C is a photograph of Experiment 4. FIG.

In Comparative Example 2, all of the five diffuser raw materials were generated at 750 cycles, and in Comparative Example 3, all of the five diffuser raw materials were generated at all of the diffuser raw materials. On the other hand, in Experimental Example 4 according to the second embodiment exhibited excellent reliability even without interfacial peeling phenomenon up to 1,000 cycles.

According to the second embodiment, the coefficient of thermal expansion between the polymer layer 146 and the adhesive member 155 is controlled by controlling the coefficient of thermal expansion of the adhesive member 155 to be in the range of 1 to 2 times that of the polymer layer 146. There is a technical effect that can greatly improve the reliability by minimizing.

Next, the surface emitting laser device 201 will be described with reference to FIGS. 10 to 12.

FIG. 10 is a plan view of the surface emitting laser device according to the embodiment, and FIG. 11 is an enlarged view of one region C1 of the surface emitting laser device according to the embodiment shown in FIG. 10.

12 is a cross-sectional view taken along line A1-A2 of the surface emitting laser device according to the embodiment shown in FIG.

10 to 12, the surface emitting laser device 201 according to the embodiment may include a light emitting part E and a pad part P. FIG. The light emitting unit E may be a region including a plurality of light emitting emitters E1, E2, and E3 as shown in FIG. 10, and may emit a laser beam. For example, the light emitting unit E may include tens to hundreds of light emitting emitters. The pad part P may be a region that is not disposed in the light emitting emitters E1, E2, and E3.

The surface emitting laser device 201 according to the embodiment may include a second electrode 282. That is, in each of the light emitting emitters E1, E2, and E3, the second electrode 282 may be disposed in the remaining regions except for the region corresponding to the aperture 241. For example, the second electrode 282 may be disposed in the second region of the second reflective layer 250. The first zero region of the second reflective layer 250 may be surrounded by the second region and may be equal to or larger than the size of the opening 241. Therefore, the beam generated in the emission layer 230 may pass through the opening 241 and be emitted to the outside through the opening defined by the second electrode 282.

Referring to FIG. 12, the surface emitting laser device 201 according to the embodiment may include a first electrode 215, a substrate 210, a first reflective layer 220, a light emitting layer 230, an oxide layer 240, and a second reflective layer. One or more of the 250, the passivation layer 270, and the second electrode 282 may be included.

The oxide layer 240 may include an opening 241 and an insulating region 242. The opening 241 may be a passage area through which current flows. The insulating region 242 may be a blocking region that blocks the flow of current. The insulating region 242 may be referred to as an oxide layer or an oxide layer. The oxide layer 240 may be referred to as a current confinement layer because it restricts the flow or density of the current to emit a more coherent laser beam.

The surface emitting laser device 201 according to the embodiment may further include a pad electrode 280. The pad electrode 280 may be disposed in an area excluding the pad part P, that is, the light emitting part E. FIG. The pad electrode 280 may be electrically connected to the second electrode 282. The first electrode 282 and the pad electrode 280 may be formed integrally or separately.

In the drawings of the embodiment, the direction of the x-axis may be a direction parallel to the longitudinal direction of the substrate 210, the y-axis may be a direction perpendicular to the x-axis.

The surface emitting laser device 201 according to the embodiment provides a substrate 210. The substrate 210 may be a conductive substrate or a nonconductive substrate. As the conductive substrate, a metal having excellent electrical conductivity may be used. Since the heat generated during the operation of the surface emitting laser device 201 should be sufficiently dissipated, a GaAs substrate or a metal substrate having high thermal conductivity or a silicon (Si) substrate may be used as the conductive substrate. As the non-conductive substrate, an AlN substrate, a sapphire (Al ₂ O ₃ ) substrate, or a ceramic-based substrate may be used.

The surface emitting laser device 201 according to the embodiment provides a first electrode 215. The first electrode 215 may be disposed under the substrate 210. The first electrode 215 may be disposed in a single layer or multiple layers of a conductive material. For example, the first electrode 215 may be a metal and include at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). Therefore, it is formed in a single layer or a multi-layer structure, it is possible to improve the electrical characteristics to increase the light output.

The surface emitting laser device 201 according to the embodiment provides the first reflective layer 220. The first reflective layer 220 may be disposed on the substrate 210. When the substrate 210 is omitted to reduce the thickness, the bottom surface of the first reflective layer 220 may contact the top surface of the first electrode 215.

The first reflective layer 220 may be doped with a first conductivity type dopant. For example, the first conductivity type dopant may include an n type dopant such as Si, Ge, Sn, Se, Te, or the like.

The first reflective layer 220 may include a gallium-based compound, for example, AlGaAs, but is not limited thereto. The first reflective layer 220 may be a distributed bragg reflector (DBR). For example, the first reflective layer 220 may have a structure in which a first layer and a second layer including materials having different refractive indices are alternately stacked at least once.

For example, the first reflective layer 220 may include a plurality of layers disposed on the substrate 210. Each layer may include a semiconductor material having a compositional formula of Al _x Ga _(1-x) As (0 <x <1), and as the Al in each layer increases, the refractive index of each layer decreases, and if Ga increases The refractive index of each layer can increase. The thickness of each layer may be λ / 4n, λ may be the wavelength of light generated in the light emitting layer 230, and n may be the refractive index of each layer for light of the above-described wavelength. Here, λ may be 650 to 980 nanometers (nm), and n may be the refractive index of each layer. The first reflective layer 220 having such a structure may have a reflectance of 99.999% for light having a wavelength of about 940 nanometers.

The thickness of the layer in each first reflective layer 220 may be determined according to the refractive index and the wavelength λ of the light emitted from the light emitting layer 230.

The surface emitting laser device 201 according to the embodiment may include a light emitting layer 230. The light emitting layer 230 may be disposed on the first reflective layer 220. In detail, the emission layer 230 may be disposed on the first reflective layer 220. The light emitting layer 230 may be disposed between the first reflective layer 220 and the second reflective layer 250.

The light emitting layer 230 may include an active layer and at least one cavity. For example, the emission layer 230 may include an active layer, a first cavity disposed below the active layer, and a second cavity disposed above the active layer. The light emitting layer 230 of the embodiment may include both the first cavity and the second cavity, or may include only one of them.

The active layer may include any one of a single well structure, a multi well structure, a single quantum well structure, a multi quantum well (MQW) structure, a quantum dot structure, and a quantum line structure.

The active layer may include a quantum well layer and a quantum wall layer using a group 3-5 or group 6 compound semiconductor material. The quantum well layer may be formed of a material having an energy band gap smaller than the energy band gap of the quantum wall layer. The active layer may be formed of one to three pair structures such as InGaAs / AlxGaAs, AlGaInP / GaInP, AlGaAs / AlGaAs, AlGaAs / GaAs, GaAs / InGaAs, but is not limited thereto. The dopant may not be doped in the active layer.

The first cavity and the second cavity may be formed of Al _y Ga _(1-y) As (0 <y <1), but are not limited thereto. For example, the first cavity and the second cavity may each include a plurality of layers of Al _y Ga _(1-y) As.

The surface emitting laser device 201 according to the embodiment may provide the oxide layer 240. The oxide layer 240 may include an insulating region 242 and an opening 241. The insulating region 242 may surround the opening 241. For example, the opening 241 may be disposed on the first area (center area) of the light emitting layer 230, and the insulating area 242 may be disposed on the second area (edge area) of the light emitting layer 230. The second region may surround the first region.

The opening 241 may be a passage region through which current flows. The insulating region 242 may be a blocking region that blocks the flow of current. The insulating region 242 may be referred to as an oxide layer or an oxide layer.

The surface emitting laser device 201 according to the embodiment may include a second reflective layer 250. The second reflective layer 250 may be disposed on the oxide layer 240.

The second reflective layer 250 may include a gallium-based compound, for example, AlGaAs, and the second reflective layer 250 may be doped with a second conductive dopant. The second conductivity type dopant may be a p-type dopant such as Mg, Zn, Ca, Sr, Ba, or the like. Meanwhile, the first reflective layer 220 may be doped with a p-type dopant, and the second reflective layer 250 may be doped with an n-type dopant.

The second reflecting layer 250 may also be a distributed Bragg reflector (DBR). For example, the second reflective layer 250 may have a structure in which a plurality of layers including materials having different refractive indices are alternately stacked at least once.

The second reflective layer 250 having such a structure may have a reflectance of 99.9% for light having a wavelength of about 940 nanometers.

The second reflective layer 250 may be formed by alternately stacking layers, and the number of pairs of layers in the first reflective layer 220 may be greater than the number of pairs of layers in the second reflective layer 250. . As described above, the reflectance of the first reflective layer 220 may be 99.999%, which may be greater than 99.9% of the reflectance of the second reflective layer 250.

In an embodiment, the second reflective layer 250 may include a plurality of layers disposed on the light emitting layer 230. Each layer may be formed of a single or a plurality of layers.

The surface emitting laser device 201 according to the embodiment may provide the passivation layer 270. The passivation layer 270 may surround a portion of the light emitting structure. Some regions of the light emitting structure may include, for example, the light emitting layer 230, the oxide layer 240, and the second reflective layer 250. The passivation layer 270 may be disposed on the top surface of the first reflective layer 220. The passivation layer 270 may be disposed on the edge region of the second reflective layer 250. When the light emitting structure is partially mesa-etched, a portion of the upper surface of the first reflective layer 220 may be exposed, and a portion of the light emitting structure may be formed. The passivation layer 270 may be disposed on a circumference of a portion of the light emitting structure and on an upper surface of the exposed first reflective layer 220.

The passivation layer 270 may protect the light emitting structure from the outside and block electrical short between the first reflective layer 220 and the second reflective layer 250. The passivation layer 270 may be formed of an inorganic material such as SiO ₂ , but is not limited thereto.

The surface emitting laser device 201 according to the embodiment may provide a second electrode 282. The second electrode 282 may be electrically connected to the pad electrode 280. The second electrode 282 may contact a portion of the top surface of the second reflective layer 250.

The second electrode 282 and the pad electrode 280 may be made of a conductive material. For example, the second electrode 282 and the pad electrode 280 may include platinum (Pt), aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), tungsten (W), and copper (Cu). ), Gold (Au) may be formed in a single layer or a multi-layer structure.

(Flip Chip Type Surface Emitting Laser Device)

13 is another cross-sectional view of the surface emitting laser device according to the embodiment.

The surface emitting laser device according to the embodiment may be applied to the flip chip type surface emitting laser device shown in FIG. 13.

In addition to the vertical type, the surface emitting laser device according to the exemplary embodiment may be a flip chip type in which the first electrode 215 and the second electrode 282 face the same direction as shown in FIG. 13.

For example, the flip chip type surface emitting laser device illustrated in FIG. 13 may include a first electrode part 215 and 217, a substrate 210, a first reflective layer 220, an active region 230, and an aperture region 240. The second reflective layer 250, the second electrode parts 280 and 282, the first passivation layer 271, the second passivation layer 272, and the anti-reflection layer 290 may be included. In this case, the reflectance of the second reflecting layer 250 may be designed to be higher than that of the first reflecting layer 220.

In this case, the first electrode parts 215 and 217 may include a first electrode 215 and a first pad electrode 217, and the first electrode on the first reflective layer 220 exposed through a predetermined mesa process. The 215 may be electrically connected, and the first pad electrode 217 may be electrically connected to the first electrode 215.

The first electrode portions 215 and 217 may be made of a conductive material, for example, metal. For example, the first electrode 215 may include a single layer or a multilayer structure including at least one of aluminum (Al), titanium (Ti), chromium (Cr), nickel (Ni), copper (Cu), and gold (Au). It can be formed as. The first electrode 215 and the first pad electrode 217 may include the same metal or different metals.

When the first reflective layer 220 is an n-type reflective layer, the first electrode 215 may be an electrode for the n-type reflective layer.

The second electrode parts 280 and 282 may include a second electrode 282 and a second pad electrode 280, and the second electrode 282 is electrically connected to the second reflective layer 250. The second pad electrode 280 may be electrically connected to the second electrode 282.

When the second reflective layer 250 is a p-type reflective layer, the second electrode 282 may be a p-type electrode.

The second electrode (see FIGS. 4 and 8) according to the above-described embodiment may be equally applied to the second electrode 282 of the flip chip type surface emitting laser device.

The first insulating layer 271 and the second insulating layer 272 may be made of an insulating material, for example, may be made of nitride or oxide, for example, polyimide, silica (SiO ₂ ), Or silicon nitride (Si ₃ N ₄ ).

(Mobile terminal)

Next, FIG. 14 is a perspective view of a mobile terminal to which a surface emitting laser device is applied according to an embodiment.

The vertical surface emitting laser device according to the embodiment and the flip surface emitting laser device shown in FIG. 13 may be applied to the mobile terminal shown in FIG. 14.

As shown in FIG. 14, the mobile terminal 1500 of the embodiment may include a camera module 1520, a flash module 1530, and an auto focusing device 1510 provided at a rear surface thereof. Here, the auto focus device 1510 may include one of a package of the surface emitting laser device according to the above-described embodiment as a light emitting layer.

The flash module 1530 may include a light emitting device that emits light therein. The flash module 1530 may be operated by camera operation of a mobile terminal or control of a user.

The camera module 1520 may include an image capturing function and an auto focus function. For example, the camera module 1520 may include an auto focus function using an image.

The auto focus device 1510 may include an auto focus function using a laser. The auto focus device 1510 may be mainly used in a condition in which the auto focus function using the image of the camera module 1520 is degraded, for example, in a proximity or a dark environment of 10 m or less. The auto focus device 1510 may include a light emitting layer including the surface emitting laser device of the above-described embodiment, and a light receiving unit for converting light energy such as a photodiode into electrical energy.

The foregoing detailed description should not be construed as limiting in all respects, but should be considered as illustrative. The scope of the embodiments should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the embodiments are included in the scope of the embodiments.

Claims (6)

A housing including a cavity;
A surface emitting laser device disposed in the cavity; And
A diffusion part disposed on the housing;
The diffusion unit,
A polymer layer; And
And a glass layer disposed on the polymer layer.
The polymer layer,
A first polymer layer vertically overlapping the surface emitting laser device;
A second polymer layer that does not vertically overlap with the surface emitting laser device,
The surface light emitting laser package having a thickness of the first polymer layer is thinner than the thickness of the second polymer layer. According to claim 1,
The thickness ratio of the second polymer layer to the first thickness of the glass layer ranges from 0.12 to 3.0. According to claim 1,
Further comprising an adhesive member between the housing and the polymer layer,
The thermal expansion coefficient of the adhesive member is in the range of 1 to 2 times the thermal expansion coefficient of the polymer layer of the surface light emitting laser package. A housing including a cavity;
A surface emitting laser device disposed in the cavity; And
A diffusion part disposed on the housing;
The diffusion unit,
A polymer layer; And
And a glass layer disposed on the polymer layer.
And a second thickness ratio of the polymer layer to the first thickness of the glass layer is in the range of 0.12 to 3.0. The method of claim 4, wherein
Further comprising an adhesive member between the housing and the polymer layer,
The thermal expansion coefficient of the adhesive member is in the range of 1 to 2 times the thermal expansion coefficient of the polymer layer of the surface light emitting laser package. A light emitting device comprising the surface emitting laser package of any one of claims 1 to 5.

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