Light emitting module testing apparatus

A light emitting module testing apparatus includes a sensing unit and a controller. The sensing unit includes a photodiode array sensing light emitted from a light emitting module serving as a test object. The controller generates luminance information based on light sensed by the sensing unit, and sets an operating condition of the light emitting module serving as the test object by comparing the generated luminance information with a pre-set reference range. The light emitting module testing apparatus thereby senses luminance of light emitted from the light emitting module serving as a test object, and sets the operating condition of the light emitting module to have an appropriate luminance.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2013-0123371 filed on Oct. 16, 2013, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

The present disclosure relates to a light emitting module testing apparatus.

Semiconductor light emitting devices, which emit light based on an electron-hole recombination principle when a current is applied thereto, are widely used as light sources. The semiconductor light emitting devices have various advantages over conventional lighting devices, including low power consumption, high degree of luminance, compactness, and the like. In particular, with the development of nitride light emitting devices, the variety of application in which light emitting modules using semiconductor light emitting devices are used has been greatly expanded to include applications in vehicle headlights, general illumination devices, camera flashes, and the like. Light emitting modules generally need to meet appropriate luminance requirements according to the products in which they are used. As a result, research is being conducted into devices that can be used to determine whether a light emitting module meets appropriate luminance requirements.

SUMMARY

An aspect of the present disclosure may provide a testing apparatus devised to sense light emitted from a light emitting module serving as a test object and to set an operating condition of the light emitting module to have an appropriate luminance.

However, objects of the present disclosure are not limited thereto and objects and effects that may be recognized from technical solutions or embodiments described hereinafter may also be included even if they are not explicitly mentioned.

According to an aspect of the present disclosure, a light emitting module testing apparatus includes a sensing unit and a controller. The sensing unit includes a photodiode array sensing light emitted from a light emitting module serving as a test object. The controller generates luminance information based on light sensed by the sensing unit, and sets an operating condition of the light emitting module serving as the test object by comparing the generated luminance information with a pre-set reference range.

The operating condition of the light emitting module set by the controller may be a current value applied by a driving unit provided in the light emitting module to a light source provided in the light emitting module.

The photodiode array may include first to nthphotodiodes, where n is a natural number greater than or equal to 2.

The luminance information generated by the controller may be a luminance profile including information regarding luminance of light sensed at locations of each of the first to nthphotodiodes.

The pre-set reference range may include a maximum reference luminance profile serving as an upper limit of the pre-set reference range and a minimum reference luminance profile serving as a lower limit of the pre-set reference range.

When the luminance profile generated by the controller has a region exceeding the maximum reference luminance profile, the controller may set the operating condition of the light emitting module so as to decrease the current value applied by the driving unit provided in the light emitting module to the light source provided in the light emitting module.

When the luminance profile generated by the controller has a region lower than the minimum reference luminance profile, the controller may set the operating condition of the light emitting module so as to increase the current value applied by the driving unit provided in the light emitting module to the light source provided in the light emitting module.

When a difference between a maximum value of the luminance profile generated by the controller and a minimum value of the luminance profile generated by the controller is greater than a difference between the maximum reference luminance profile and the minimum reference luminance profile, the controller may determine that the light emitting module is defective.

At least one of the maximum reference luminance profile and the minimum reference luminance profile may have a linear shape.

At least one of the maximum reference luminance profile and the minimum reference luminance profile may have a curved shape.

The sensing unit may include first to mthphotodiode arrays each including first to nthphotodiodes, where m and n are natural numbers greater than or equal to 2, and the luminance information generated by the controller may be a single average luminance profile derived by averaging first to mthluminance profiles respectively obtained by the first to mthphotodiode arrays.

The sensing unit may be disposed to be positioned directly above a main light emitting surface of the light emitting module.

The photodiode array may include first to nthphotodiodes, where n is a natural number greater than or equal to 2, and the sensing unit may include a bar-like light receiving part in which the photodiode array is disposed.

The sensing unit may include first to mthphotodiode arrays each including first to nthphotodiodes and first to mthbar-like light receiving parts in which the first to mthphotodiode arrays are respectively disposed, where n and m are natural numbers greater than or equal to 2.

According to another aspect of the present disclosure, a light emitting module testing apparatus may include a sensing unit and a controller. The sensing unit includes a photodiode array sensing light emitted from a light emitting module, serving as a test object, has a light source, and has a driving unit providing a pre-selected current to drive the light source. The controller generates luminance information based on light sensed by the sensing unit, and compares the luminance information with a pre-set reference range to set the pre-selected current value applied by the driving unit provided in the light emitting module to the light source such that the luminance information of light emitted from the light emitting module serving as the test object satisfies the pre-set reference range.

According to another aspect of the present disclosure, a light emitting module testing apparatus may include a sensing unit and a controller. The sensing unit may include a plurality of photodiodes disposed on a substrate for sensing, at locations of each of the plurality of photodiodes, light emitted from a light emitting module serving as a test object. The controller may be coupled to the sensing unit, may generate a luminance profile including, for each respective location of a plurality of locations of the photodiodes, luminance information of light sensed at the respective location, and may generate a control signal based on comparing the luminance information of light sensed at each respective location with a pre-set luminance range for the respective location.

Each photodiode of the plurality of photodiodes may be connected to a respective transistor, and the controller may receive an electrical signal from each respective transistor connected to a photodiode of the plurality of photodiodes indicative of luminance of light sensed at the location of the respective photodiode.

The controller may generate the luminance profile by averaging, for each of a plurality of locations of photodiodes, luminance information of light sensed by photodiodes at or proximate to the respective location, and may generate the control signal based on comparing the averaged luminance information of light sensed at each location with a pre-set luminance range for the respective location.

The pre-set luminance range may include different luminance ranges for different ones of the locations of the photodiodes.

The sensing unit may be disposed to be positioned directly above a main light emitting surface of the light emitting module.

According to another aspect of the present disclosure, a method of manufacturing a lighting device may include preparing a light source, preparing a light emitting module as a test target with prepared light source, testing the light emitting module, and preparing a lighting device with the light emitting module having undergone testing.

The testing of the light emitting module may include driving the light emitting module, sensing light emitted from the light emitting module, generating luminance information of the sensed light, comparing the luminance information with a pre-set reference range, and setting an operating condition of the light emitting module as a test target according to the comparison result.

The foregoing technical solutions do not fully enumerate all of the features of the present disclosure. The foregoing and other objects, features, aspects and advantages of the present disclosure will become more apparent from the following detailed description of the present disclosure when taken in conjunction with the accompanying drawings.

DETAILED DESCRIPTION

FIG. 1schematically illustrates a light emitting module testing system1000according to an exemplary embodiment of the present disclosure.

Referring toFIG. 1, the light emitting module testing apparatus according to the present exemplary embodiment may test a light emitting module200, serving as a test object, and set an operating condition of the light emitting module200as a test target.

In the present exemplary embodiment, the light emitting module200, serving as a test object, may have a light source210disposed on a substrate230. A plurality of light sources210may be provided in the light emitting module200, and each of the plurality of light sources210may include a semiconductor device (for example, a light emitting diode (LED)) emitting light when a current is applied thereto, but the present disclosure is not limited thereto. The light emitting module200may include a driving unit220electrically connected to the plurality of light sources210to provide a current for driving the light sources210. Here, luminance of the light emitting module200may vary according to a magnitude of a current value applied to the light sources210from the driving unit220.

The light emitting module200may need to satisfy appropriate luminance conditions according to a product to which the light emitting module200is to be applied. For example, a light emitting module used in a vehicle headlight may need to satisfy luminance conditions at a predetermined distance stipulated in regulations. To this end, the light emitting module200may be manufactured by setting the number of light sources210to be provided in the light emitting module200and an appropriate current value to be applied by the driving unit220to the plurality of light sources210to drive the light sources210in advance, in consideration of the luminance of light emitted by each of the light sources210. However, the light emitting module220may exhibit an inappropriate luminance due to a processing error, or the like, occurring while manufacturing one or more of the light source(s)210and the driving unit220. Thus, an exemplary embodiment of the present disclosure provides the light emitting module testing apparatus100capable of measuring the luminance of the light emitting module200and providing feedback on measurement results to allow for correction of the luminance of the light emitting module200.

In the present exemplary disclosure, the light emitting module testing apparatus100may include a sensing unit110measuring luminance of the light emitting module200and a controller120correcting the luminance of the light emitting module200according to luminance measurement results.

The sensing unit110may be disposed to be positioned directly aligned with and above a main light emitting surface of the light emitting module200. The sensing unit110may be disposed directly above and spaced apart from the light emitting module200at a distance t ranging from 50 cm to 100 cm, but the present disclosure is not limited thereto.

The sensing unit110may include photodiode arrays (PDA) sensing light emitted by the light emitting module200as a test object. The sensing unit110may include at least one light receiving part11,12,13, and14having a bar-like shape, and the photodiode arrays PDA may be disposed in each of the light receiving parts11,12,13, and14. In the light receiving parts11,12,13, and14, the photodiode arrays PDA may be disposed on a surface A facing the light emitting module200(e.g., facing a surface of the light emitting module200on which light sources210are disposed).

The photodiode arrays PDA may be provided as first to mthphotodiode arrays PDA (m is a natural number greater than or equal to 2), and the first to mthphotodiode arrays PDA may be disposed in a corresponding first to mthbar-like light receiving parts (e.g., light receiving parts11,12,13, and14). In this case, a number and/or disposition of the light receiving parts provided in the sensing unit110may be appropriately changed according to a size and/or shape of the light emitting module200serving as the test object, so that testing and correction operations may be more effectively performed on the light emitting module200. In the present exemplary embodiment, the photodiode arrays PDA are provided as first to fourth photodiode arrays and disposed in first to fourth light receiving parts11,12,13, and14, respectively, but the number of light receiving parts may be appropriately changed as necessary.

FIGS. 2A and 2Bschematically illustrate the light receiving part11and a circuit diagram illustrating a portion of a circuit constituting the photo diode array, respectively, according to the present exemplary embodiment.

Referring toFIG. 2A, the photodiode array PDA disposed in the light receiving part11includes first to nthphotodiodes PD1to PD12(n is a natural number greater than or equal to 2). The photodiodes PD1to PD12are sensors that operate according to a photovoltaic effect, and are semiconductor devices that convert optical energy into electrical energy. Namely, when light is sensed, the photodiodes PD1to PD12are turned on to allow a current to flow, and a magnitude of an output voltage proportionally increases according to the intensity of sensed light. In the present exemplary embodiment, the photodiode array PDA is illustrated as including the first to twelfth photo diodes PD1to PD12arranged in a row. However, the arrangement pattern and number of photodiodes provided in the photodiode array PDA may be appropriately changed as necessary.

FIG. 2Bis a circuit diagram illustrating a portion of the circuit constituting the photodiode array PDA. However, the circuit diagram is merely illustrative to allow easy understanding of the present exemplary embodiment, and the present disclosure is not limited thereto.

Referring toFIG. 2B, an anode and a cathode of each of the first to twelfth photodiodes PD1to PD12are respectively connected to a base and a collector of a corresponding transistor among first to twelfth transistors Q1to Q12. An emitter of each of the first to twelfth transistors Q1to Q12is connected to one terminal of a corresponding sensing resistor R1to R12, and another terminal of each of the sensing resistors R1to R12is connected to ground. Magnitudes V1 to V12 of voltages applied to respectively ones of the sensing resistors R1to R12by the photodiodes PD1-PD12and transistors Q1-Q12may vary according to an intensity of light sensed at positions of the first to twelfth photodiodes PD1to PD12. Thus, the light receiving part11may deliver an electrical signal V1-V12 corresponding to the intensity of light sensed in the positions of each of the first to twelfth photodiodes PD1to PD12to the controller120. According to the present exemplary embodiment, luminance of light sensed in the positions of each of the photodiodes PD1to PD12may be precisely converted into an electrical signal and delivered to the controller120by using the photodiodes PD1to PD12.

The controller120may generate luminance information corresponding to light sensed by the sensing unit110, and compare the luminance information with a pre-set reference range to set an operating condition of the light emitting module200as a test target. For example, in the present exemplary embodiment, the controller120may generate luminance information corresponding to light sensed by the first to fourth light receiving parts11,12,13, and14provided in the sensing unit110from electrical signals regarding light sensed by the first to fourth light receiving parts11,12,13, and14. Here, the luminance information may be a luminance profile including information regarding luminance of light sensed in the region in which the first to nthphoto diodes are disposed in each light receiving part. This will be described in more detail with reference toFIGS. 1,3A, and3B.

FIG. 3Aillustrates first to fourth luminance profiles P1, P2, P3, and P4 including information regarding luminance of light sensed by each of the first to fourth light receiving parts11,12,13, and14, and an average luminance profile Pm derived by averaging the first to fourth luminance profiles P1, P2, P3, and P4.

First, profiles i) to iv) shown on the left side ofFIG. 3Aillustrate the first to fourth luminance profiles P1, P2, P3, and P4 corresponding to the luminance information of light sensed by the first to fourth light receiving parts11,12,13, and14, respectively. Here, each of the first to fourth luminance profiles P1, P2, P3, and P4 may be understood as a line formed by connecting luminance value measurements corresponding to light sensed by the first to twelfth photodiodes PD1to PD12disposed in a corresponding one of the first to fourth light receiving parts11,12,13, and14.

Meanwhile, as illustrated, the second and third profiles P2 and P3 have luminance information of light sensed by the second and third light receiving parts12and13facing an interior region of the main light emitting surface of the light emitting module200. As such, the second and third profiles P2 and P3 may have luminance measurement values that are higher than those of the first and fourth luminance profiles P1 and P4, since luminance information sensed by the first and fourth light receiving parts11and14facing an outer side or outer perimeter of the main light emitting surface of the light emitting module200. However, such results may vary according to the shape and disposition of the light emitting module200.

Also, as illustrated, the luminance profiles P1-P4 and Pm are plotted with values along the vertical axis in lumen [lm], a measurement unit of the velocity of light. However, the present disclosure is not limited thereto and, for example, the luminance profiles can be plotted according to units of volt [V] or ampere [A] of electrical signals converted by the first to nthphotodiodes provided in the respective light receiving parts.

The profile illustrated on the right side ofFIG. 3Ais a single average luminance profile Pm derived by averaging the first to fourth luminance profiles P1, P2, P3, and P4. The average luminance profile may include a plurality of average luminance values each corresponding to an average of luminance values sensed by photodiodes located at and proximate to a respective location. In the present exemplary embodiment, the controller120may compare the average luminance profile Pm with a pre-set reference range. Here, the pre-set reference range may include a maximum reference luminance profile Ref.H as an upper limit of the reference range and a minimum reference luminance profile Ref.L as a lower limit of the reference range as described hereinafter with reference toFIG. 3B.

FIG. 3Billustrates the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L. In the present exemplary embodiment, the controller120may determine whether the average luminance profile Pm is within a range defined by the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L, and correct the luminance of the light emitting module200according to the determined results. In detail, the controller120may generate a control signal to set an operating condition of the light emitting module200according to the determined results, and here, the operating condition of the light emitting module200set by the controller120may be a pre-selected current value applied by the driving unit220provided in the light emitting module200to the light sources210provided in the light emitting module200. Details thereof will be described hereinafter with reference toFIGS. 4A through 6.

FIGS. 4A through 6are luminance profiles specifically illustrating an operating principle used by the controller120to set an operating condition of the light emitting module200by comparing luminance information with the pre-set reference range according to the present exemplary embodiment.

First, as illustrated inFIGS. 4A and 4B, luminance information of light sensed by the sensing unit110, for example an average luminance profile Pm, may include a region exceeding the maximum reference luminance profile Ref.H serving as an upper limit of the pre-set reference range. In detail,FIG. 4Aillustrates a case in which a pre-selected current value applied by the driving unit220provided in the light emitting module200to the light sources210provided in the light emitting module200is set to be too high, andFIG. 4Billustrates a case in which a pre-selected current value applied by the driving unit220to the light sources210is appropriately set but a fault (over-output) occurs in some light sources210.

In the illustrative cases shown inFIGS. 4A and 4B, the controller120may set an operating condition of the light emitting module200(for example, a pre-selected current value applied by the driving unit220provided in the light emitting module200to the light sources210provided in the light emitting module200) such that the pre-selected current value is reduced so the average luminance profile Pm does not to exceed the maximum reference luminance profile Ref.H. Thus, a luminance profile of light emitted by the light emitting module200may be corrected to satisfy the pre-set reference range Pm′ indicated by the alternated long and short dash lines shown inFIGS. 4A and 4B.

To this end, the controller120may be connected to the driving unit220provided in the light emitting module200as illustrated inFIG. 1. The controller120may also provide predetermined direct current (DC) or alternating current (AC) driving power to the driving unit220while testing is performed on the light emitting module200, but the present disclosure is not limited thereto. In this case, the type (DC or AC) of driving power provided by the controller120to the driving unit220may vary according to a type of power applied (or received) from the outside when the light emitting module200is used in a product. For example, when the light emitting module200is used in a product that is driven by DC power received from the outside, the controller120may provide the predetermined DC power to the driving unit200while testing is performed, and when the light emitting module200is used in a product that is driven by AC power received from the outside, the controller120may provide the predetermined AC power to the driving unit200while testing is performed. However, the present disclosure is not limited thereto and the driving unit220may receive the predetermined driving power from the outside, rather than from the controller120, while testing is being performed on the light emitting module200.

Meanwhile, as illustrated inFIGS. 5A and 5B, the luminance information, for example, the average luminance profile Pm, sensed by the sensing unit110may include a region lower than the minimum reference luminance profile Ref.L serving as a lower limit of the pre-set reference range.

In detail,FIG. 5Aillustrates a case in which a pre-selected current value applied from the driving unit220provided in the light emitting module200to the light sources210provided in the light emitting module200is set to be too low, andFIG. 5Billustrates a case in which a pre-selected current value applied from the driving unit220to the light sources210is set to be appropriate, but some light sources210are defective (i.e., do not operate).

In the illustrative cases shown inFIGS. 5A and 5B, the controller120may set an operating condition of the light emitting module200(for example, a current value applied by the driving unit220provided in the light emitting module200to the light sources210provided in the light emitting module200) such that the pre-selected current value is increased so the average luminance profile Pm is not lower than the minimum reference luminance profile Ref.L. Thus, a luminance profile of light emitted by the light emitting module200may be corrected to satisfy the pre-set reference range Pm′ indicated by the alternating long and short dash lines shown inFIGS. 5A and 5B.

In addition, as illustrated inFIG. 6, the average luminance profile Pm may have a region exceeding the maximum reference luminance profile Ref.H and a region lower than the minimum reference luminance profile Ref.L according to a degree of defect of the light emitting module200. Here, although the driving unit220applies an optimized current value to the light sources210, the light emitting module200may not satisfy the pre-set reference range. In this case, the controller120according to the present exemplary embodiment may determine that the light emitting module200is defective.

In detail, for example, the controller120may calculate a difference D2 between a maximum value and a minimum value of the average luminance profile Pm and compare the calculation result with a difference D1 between the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L. When the calculation result D2 is greater than the difference D1 between the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L (namely, in the case of D2>D1), the controller120may determine that the light emitting module200is defective.

FIG. 7is a flow chart illustrating an example of a process performed in the controller120while the light emitting module is being tested.

Referring toFIG. 7, the controller120generates the luminance information from light sensed by the sensing unit110(S10). As described above, the luminance information may be an average luminance profile Pm derived by averaging luminance profiles including information regarding luminance of light sensed at locations of the first to nthphotodiodes disposed in the first to mthlight receiving parts provided in the sensing unit110.

Next, the controller120may calculate a difference D2 between a maximum value of the average luminance profile Pm and a minimum value thereof, and compare the calculation result D2 with a difference D1 between a maximum value of a pre-set reference range and a minimum value of the pre-set reference range (S20). Here, the difference between the maximum value of the pre-set reference range and the minimum value thereof may be a difference between a maximum reference luminance profile Ref.H as an upper limit of the reference range and a minimum reference luminance profile Ref.L as a lower limit of the reference range.

When the difference D2 between the maximum value and the minimum value of the average luminance profile Pm is greater than the difference between the maximum value and the minimum value of the pre-set reference range, the controller120may determine that the light emitting module200is defective (S30) and may terminate testing.

Meanwhile, when the difference D2 between the maximum value and the minimum value of the average luminance profile Pm is smaller than or equal to the difference between the maximum value and the minimum value of the pre-set reference range, the controller120determines whether the average luminance profile Pm is within the pre-set reference range (S40). If it is determined that the average luminance profile Pm is within the pre-set reference range, the controller120sets a present current value applied by the driving unit220of the light emitting module200to the light sources210as an output current value of the driving unit220and terminates the test (S50). On the other hand, if it is determined that the average luminance profile Pm exceeds the pre-set reference range, the controller120determines whether the average luminance profile Pm has a region exceeding the maximum reference luminance profile Ref.H serving as an upper limit of the pre-set reference range (S41). If it is determined that the average luminance profile Pm has a region exceeding the maximum reference luminance profile Ref.H, the controller120adjusts the current value applied by the driving unit220of the light emitting module200to the light sources210such that it is decreased (S42). Conversely, if it is determined that the average luminance profile Pm does not have a region exceeding the maximum reference luminance profile Ref.H, the controller120adjusts the current value applied by the driving unit220of the light emitting module200to the light sources210such that it is increased (S43). Thereafter, the controller12repeats the operation of generating the luminance information from light sensed in the light emitting module200to set an operating condition (e.g., a current value) of the light emitting module200so that the light emitting module200may have an appropriate luminance.

Hereinafter, other elements of the light emitting module testing apparatus100according to the present exemplary embodiment will be described with reference toFIG. 1.

Referring toFIG. 1, the light emitting module testing apparatus100may further include a display unit130configured to display at least one type of information among the luminance information (e.g., the average luminance profile Pm) generated by the controller120, the pre-set reference range (e.g., the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L), the comparison result of the luminance information and the reference range, and information on whether the light emitting module200as a test object is defective.

According to the present exemplary embodiment, the light emitting module testing apparatus100senses luminance of light emitted from the light emitting module200serving as a test object and sets an operating condition of the light emitting module200to have appropriate luminance.

FIGS. 8A through 8Cillustratively show sensing units110a,110b, and110cprovided in a light emitting module testing apparatus according to another exemplary embodiment of the present disclosure.

As illustrated inFIGS. 8A and 8B, the sensing units110aand110bmay include at least one light receiving part11a,12a,11b, and12bin which photodiode arrays PDA are disposed (in the present exemplary embodiment, two light receiving parts are illustrated as being included in each of the sensing units110aand110b). The light receiving parts11a,12b,11b, and12bmay include photodiode arrays PDA that each include first to nthphotodiodes PD1, PD2, PD3, and the like. Here, unlike in the exemplary embodiment ofFIGS. 1 and 2, the light receiving parts11a,12b,11b, and12bmay have a closed-loop shape. For example, the light receiving parts11aand12aillustrated inFIG. 8Amay have a circular closed-loop shape (e.g., a donut shape), and the light receiving parts11band12billustrated inFIG. 8Bmay have a quadrangular closed-loop shape. In this case, the other light receiving parts12aand12bmay each have a closed-loop shape that fits into and can be disposed within the corresponding closed-loop shape11aand11bdescribed above. Also, as illustrated inFIG. 8C, a light receiving part11cmay have a square shape. Shapes and dispositions of the light receiving parts and photodiodes may be appropriately modified according to conditions such as shapes and dispositions of the light emitting module serving as a test object.

FIG. 9illustratively shows a light emitting module testing system1001according to another exemplary embodiment of the present disclosure. The light emitting module testing system1001according to the present exemplary embodiment may be understood as being identical to that of the former exemplary embodiment as described above, except for the shape of a light emitting module serving as a test object and the shapes of maximum and minimum reference luminance profiles.

In detail, as illustrated inFIG. 9, the light emitting module201serving as a test object in the present exemplary embodiment may be a light emitting module configured for use in a vehicle headlight. The light emitting module201may include a plurality of light sources211disposed on a substrate231and a driving unit220for driving the light sources211. A main light emitting surface of the light emitting module201may have a closed-loop shape (e.g., a donut shape). In this case, since no light source211is present in an inner or central portion of the closed-loop shape, luminance measured in the internal or central region of the sensing unit110may be low. Thus, a pre-set reference range input to the controller120may be set in consideration of the shape of the light emitting module201.

In detail, in the exemplary embodiment ofFIG. 3B, the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L are illustrated as having a linear shape, but the shapes of the maximum reference luminance profile Ref.H and the minimum reference luminance profile Ref.L may be appropriately modified according to the shape and disposition pattern of the light sources211on the light emitting module201. As such, in the exemplary embodiment ofFIG. 9, maximum and minimum reference luminance profiles Ref.H1 and Ref.L1 may be modified to have curved shapes as illustrated inFIG. 10. In the present exemplary embodiment, the curved shapes are illustrated as being downwardly concave, but they may more generally be modified in other ways according to the shapes and disposition patterns of light sources on a light emitting module serving as a test object.

FIGS. 11 and 12illustratively show a lighting device employing a light emitting module according to an exemplary embodiment of the present disclosure.

In detail, the light emitting module test system according to the present exemplary embodiment is not limited to use with vehicle headlight, and may more generally be used with a bulb-type and/or L-tube type lighting device as illustrated inFIGS. 11 and 12.

For example, a lighting device2000may be a bulb-type lamp as illustrated inFIG. 11. The lighting device2000may have a shape similar to that of an incandescent lamp in order to replace a conventional incandescent lamp and may output light having optical characteristics (e.g., color, color temperature, and the like) similar to those of an incandescent lamp.

Referring to the exploded perspective view ofFIG. 11, the lighting device2000includes a light emitting module2204and an external connection unit2209. Also, the lighting device2000may further include external structures such as external and internal housings2206and2208and a cover unit2207. The light emitting module2204may include a light source2201, a substrate2202on which the light source is mounted, and a driving unit2203for driving the light source2201.

In the lighting device2000, the light emitting module2204may include the external housing2206acting as a heat dissipation unit, and the external housing2206may include a heat dissipation plate2205directly in contact with the light emitting module2204in order to have an enhanced heat dissipation effect. The lighting device2000may include the cover unit2207mounted on the light emitting module2204and having a convex lens shape. The driving unit2203may be installed in the internal housing2208and receive power provided from the external connection unit2209having a socket structure.

Referring to the exploded perspective view ofFIG. 12, a lighting device3000according to the present exemplary embodiment may include a light emitting module3203, a body unit3304, and a terminal unit3209, and may further include a cover unit3207.

The light emitting module3203may include a substrate3202, a plurality of light sources3201mounted on the substrate3202, and a driving unit3204for driving the plurality of light sources3201.

The body unit3304may allow the light emitting module3203to be fixedly installed on one surface thereof. The body unit3304, a type of support structure, may include a heat sink. The body unit3304may be made of a material having excellent heat conductivity to outwardly dissipate heat generated by the light emitting module3203. For example, the body unit3304may be formed of a metal, but the present disclosure is not limited thereto.

The body unit3304may have a generally elongated bar-like shape corresponding to the shape of the substrate3202of the light emitting module3203. The body unit3304may have a recess3334formed on one surface thereof to accommodate the light emitting module3203therein.

A plurality of heat dissipation fins3314may be protruded from both outer surfaces of the body unit3304to dissipate heat.

Stoppage grooves3324may be formed in both edges of the outer surface positioned above the recess3334and extend in a length direction of the body unit3304. The cover unit3207described below may be fastened to the stoppage grooves3324.

Both end portions of the body unit3304in the length direction thereof may be open, and the body unit3304may have a pipe structure with both end portions thereof open. In the present exemplary embodiment, the body unit3304is illustrated as having a structure in which both end portions thereof are open, but the present disclosure is not limited thereto. For example, only one of both end portions of the body unit3304may be open.

The terminal unit3209may be provided in at least open side among both end portions of the body unit3304in the length direction to supply power to the light emitting module3203. In the present exemplary embodiment, both end portions of the body unit3304are open, so the terminal unit3209is illustrated to be disposed in both end portions of the body unit3304. However, the present disclosure is not limited thereto, and when the body unit3304has a structure in which only one side thereof is open, the terminal unit3209may be provided in the single open end portion among both end portions of the body unit3304.

The terminal unit3209may be fastened to both open end portions of the body unit3304in order to cover the open end portions. The terminal unit3209may include electrode pins3219protruding outwards.

The cover unit3207is fastened to the body unit3304to cover the light emitting module3203. The cover unit3207may be formed of a material allowing light to be transmitted therethrough.

The cover unit3207may have a semicircular curved surface allowing light to be generally irradiated outwards in a uniform manner. Protrusions3217may be formed on a bottom surface of the cover unit3207fastened to the body unit3304, in a length direction of the cover unit3207, and engaged with the stoppage grooves3324of the body unit3304.

In the present exemplary embodiment, the cover unit3207is illustrated as having a semicircular shape, but the present disclosure is not limited thereto. For example, the cover unit3207may have a flat quadrangular shape or may have any other polygonal shape. The shape of the cover unit3207may be variously modified according to an illumination design in which light is irradiated.

Hereinafter, a method for manufacturing a lighting device according to an exemplary embodiment of the present disclosure will be described.

FIG. 13is a flow chart illustrating a method for manufacturing a lighting device according to an exemplary embodiment of the present disclosure.

Referring toFIG. 13, the method for manufacturing a lighting device according to the present exemplary embodiment may include operation S100to prepare a light source, operation S200to prepare a light emitting module as a test object of the light source, operation S300to test the light emitting module, and operation S400to prepare a lighting device with the test-finished light emitting module. Hereinafter, the manufacturing method according to the present exemplary embodiment will be described in detail with reference toFIGS. 14 through 17.

FIG. 14is a cross-sectional view illustrating a light source212that may be used in the method for manufacturing a lighting device according to the present exemplary embodiment, such as a lighting device having undergone operation S100to prepare a light source.

In the present exemplary embodiment, the light source212may include a semiconductor device (e.g., an LED20) emitting light when a current is applied thereto. In this case, the LED20may include an n-type semiconductor layer, a p-type semiconductor layer, and an active layer disposed therebetween. The active layer may be formed as a nitride semiconductor having a single or multi-quantum well structure and including InxAlyGa1-x-yN(0≦x≦1, 0≦y≦1, x+y≦1), and may emit blue light.

In the present exemplary embodiment, the light source212may include a package body30in which the LED20is disposed. The package body30may include a cavity accommodating the LED20and a pair of lead frames31aand31b. The package body30may be formed of an opaque resin or a resin having a high degree of reflectivity. The package body30may be provided by using a polymer resin that may easily undergo an injection molding process. However, the present disclosure is not limited thereto and the package body30may be formed of various non-conductive materials.

The pair of lead frames31aand31bmay be electrically connected to the LED20by using conductive wires W or being brought into contact with the LED20, and may be used as a terminal for applying an external electrical signal. To this end, the lead frames31aand31bmay be formed of a metal having excellent electrical conductivity.

An encapsulator32filling the cavity may be formed of a light-transmissive resin such as silicon or epoxy. The encapsulator32may include a wavelength conversion material excited by an excitation light source (e.g., LED20) to emit light having a wavelength different from that of the excitation light source. The wavelength conversion material33may include at least one of a phosphor and a quantum dot.

FIG. 15is a perspective view specifically illustrating operation S200to prepare a light emitting module202as a test object with the light source.

Referring toFIG. 15, operation S200may include an operation to dispose the light source212completed in the previous operation S100on the substrate232. Here, a plurality of light sources212may be disposed on the substrate232.

Next, the light sources212disposed on the substrate232may be electrically connected to a driving unit222providing driving power thereto. The driving unit222may include a rectifier, a DC/DC converter, or the like, providing a constant current to the light sources212. Also, the driving unit222may include an integrated chip (IC) circuit for providing a predetermined appropriate current value to the light sources212.

FIG. 16is a flow chart illustrating operation S300to test a light emitting module.

Referring toFIG. 16, operation S300to test a light emitting module may include operation S301to drive the light emitting module as a test object, operation S302to sense light emitted from the light emitting module while it is being driven, operation S303to generate luminance information of the sensed light, operation S304to compare the luminance information with a pre-set reference range and determine whether the light emitting module is defective, and operation S305to set an operating condition of the light emitting module as a test object or operation S306to discard the light emitting module as a test object. Operation S300may be performed by using the light emitting module testing apparatus100as described above.

In this case, operation S302to sense light emitted from the light emitting module may be performed by the sensing unit110, and operations S303to generate luminance of the sensed light, S304to compare the luminance information with the pre-set reference range, and S305to set an operating condition of the light emitting module as a test object may be performed by the controller120. By comparing the luminance information with the pre-set reference range (S304), the controller120may determine whether the light emitting module is defective.

FIGS. 17A through 17Cillustratively show lighting devices that have undergone testing. In detail, the lighting device may be a bulb-type lighting device2000or an L-tube type lighting device3000, respectively, as illustrated inFIGS. 17A and 17B. Here, a “lighting device” is not particularly limited in its purpose for illumination. Additionally, the lighting device may be understood as a concept including a vehicle headlight4000as shown inFIG. 17C.

According to the present exemplary embodiment, the lighting device having a light emitting module whose operating condition is set to have an appropriate luminance may be efficiently manufactured.

As set forth above, according to exemplary embodiments of the present disclosure, a light emitting module testing apparatus is capable of sensing luminance of light emitted from a light emitting module serving as a test object, and setting an operating condition of the light emitting module to have an appropriate luminance.

Advantages and effects of the present disclosure are not limited to the foregoing content and any other technical effects not mentioned herein may be easily understood by a person skilled in the art from the foregoing description.