KR100794330B1 - Apparatus and method for testing back light unit of liquid crystal display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test apparatus and a method of a backlight unit for a liquid crystal display device for measuring the luminance of a backlight unit disposed on a rear surface of a liquid crystal panel to irradiate light to the liquid crystal panel. To this end, the device of the present invention, a test device for a backlight unit for a liquid crystal display device, comprising: a sensing unit disposed on the back of the backlight unit, for detecting the brightness of light leaking from the reflective sheet of the backlight unit; A level detector detecting a voltage level that varies according to the brightness of the detected light; A controller for determining whether the voltage level is a level of a reference range preset by a user; And a notification unit for outputting a notification signal according to the determination result of the control unit.

Back light unit, brightness, back, detector, receiver, table

Description

Apparatus and method for testing back light unit of liquid crystal display}

1 is a view schematically showing a test device structure of a backlight unit according to a first embodiment of the present invention.

2 is a flowchart schematically illustrating a test process of a backlight unit according to a first embodiment of the present invention.

3 is a perspective view illustrating a test apparatus of a backlight unit according to a second embodiment of the present invention;

4 is a detailed view of portion A of FIG.

5 is a side view of FIG. 1;

Figure 6 is a cross-sectional view showing the structure of the secondary housing according to a second embodiment of the present invention.

7 is a cross-sectional view showing the structure of a hinge device according to a second embodiment of the present invention.

8 is a perspective view showing a test apparatus of a backlight unit according to a second preferred embodiment of the present invention.

9 is a perspective view showing the structure of a pallet according to a third embodiment of the present invention.

10 is a perspective view showing a test inspection state of a backlight unit using the test apparatus of the backlight unit according to the third embodiment of the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit for a liquid crystal display device, and more particularly, to a test apparatus and method for a backlight unit for measuring a brightness of a backlight unit disposed on a rear surface of a liquid crystal panel for irradiating light to the liquid crystal panel. will be.

Liquid crystal displays have been developed as a display element that replaces CRTs based on the advantages of low weight, low voltage driving, and low power consumption. In particular, thin film transistor liquid crystal displays have achieved high quality, large size, and color that are comparable to CRT. It is used in various fields. Unlike the CRT, the liquid crystal display is not a display device that emits light by itself, and thus a separate light source is provided on the rear surface of the liquid crystal panel to visually express an image. As a light source of a liquid crystal display device, a lamp or LED is currently used, and a back light unit having such a light source irradiates surface light to the liquid crystal panel.

Although not shown, the backlight unit may include a light source for emitting light, a light guide plate spaced apart from the side of the light source to transmit the light emitted from the light source to the liquid crystal panel, a lamp reflector surrounding the light source, and a rear surface of the light guide plate. It includes a reflective sheet installed to return the light exiting the back of the light guide plate back to the light guide plate, and a diffusion sheet, a prism sheet and a protective sheet which are sequentially provided on the front surface of the light guide plate. After the components are stacked and assembled in a mold frame, the parts are fastened to the liquid crystal panel by a bezel and a back cover to form a liquid crystal display device.

In such a backlight unit, the brightness of light irradiated to the liquid crystal panel is an important problem in irradiating light to the liquid crystal panel. In other words, the brightness of the light irradiated from the backlight unit to the liquid crystal panel should be a predetermined size in order to visually express the image. Accordingly, the image quality of the image represented by the liquid crystal display device depends on the brightness of the light. In addition, the sheets constituting the backlight unit are required to be thin in order to reduce the thickness of the liquid crystal display device and to improve the irradiation efficiency of light emitted from the light source. However, thinned sheets provide technical difficulties in the assembly process of the backlight unit, and for example, a thin sheet may be assembled more than necessary in the backlight unit. The sheets assembled more than necessary have a problem of reducing the image quality of the image represented by the liquid crystal display by reducing the brightness of the light emitted from the backlight unit to the liquid crystal panel, and also increasing the production cost of the liquid crystal display.

Accordingly, in the fabrication process of the liquid crystal display device, before the assembled backlight unit is fastened to the liquid crystal panel, a test process of measuring luminance of light emitted from the backlight unit is performed. This test process has a problem that the workability is deteriorated by the operator by measuring the brightness of the light irradiated to the front by the backlight unit manually by using a luminance meter. In addition, the operator must measure the brightness of the light leaking to the back of the backlight unit through the reflective sheet of the backlight unit, for this purpose, the operator has to turn over the backlight unit has a problem that the workability is significantly reduced.

Accordingly, an object of the present invention is to provide a liquid crystal display capable of automatically and accurately measuring the luminance of light leaking to the rear surface of the backlight unit through a reflective sheet of the backlight unit disposed on the rear surface of the liquid crystal panel and irradiating light to the liquid crystal panel. The present invention provides a test apparatus and method for a backlight unit for a device.

Another object of the present invention is to provide a test apparatus for a backlight unit for a liquid crystal display device capable of activating a test process for a backlight unit.

In order to achieve the above object, the device of the present invention is a test device for a backlight unit for a liquid crystal display device, the sensing unit is disposed on the back of the backlight unit, the sensing unit for detecting the brightness of light leaking from the reflective sheet of the backlight unit ; A level detector detecting a voltage level that varies according to the brightness of the detected light; A controller for determining whether the voltage level is a level of a reference range preset by a user; And a notification unit for outputting a notification signal according to the determination result of the control unit.

In order to achieve the above object, another apparatus of the present invention is a test apparatus for a backlight unit for a liquid crystal display device, comprising: a table on which the backlight unit is placed; At least one fixing part fixed to the backlight unit mounted on the table; A light receiving unit mounted on a rear surface of the table and exposed to the surface of the table to measure the brightness of the backlight unit; And a controller configured to receive the measured luminance from the light receiving unit, compare the measured luminance with two luminance values previously input by the user, and determine whether the backlight unit is defective.

In order to achieve the above object, another apparatus of the present invention is a test apparatus for a backlight unit for a liquid crystal display device, the sensing unit which is provided on a conveyor to which the backlight unit passed through the assembly process is transferred to detect whether the backlight unit is in progress. ; A stopper for protruding forward of the backlight unit in the forward direction of the backlight unit when the backlight unit is detected by the sensing unit to stop the backlight unit at a predetermined position; A light receiving unit which moves closer to a sensing hole provided in the bottom plate frame of the backlight unit stopped by the stopper to measure the brightness of the backlight unit; A driving unit which fixes the stopper and the light receiving unit to the conveyor and operates the stopper and the light receiving unit; And a controller configured to operate the driving unit based on a detection signal of the sensing unit, and determine whether the backlight unit is defective by comparing the luminance measured by the light receiving unit with two luminance values previously input by the user. do.

According to an aspect of the present invention, there is provided a method of testing a backlight unit for a liquid crystal display device, the method comprising: sensing brightness of light leaking from a reflective sheet of the backlight unit; Detecting a voltage level that varies in accordance with the sensed brightness of the light; Determining whether the voltage level is a level of a reference range preset by a user; And outputting a predetermined notification signal according to the determination result.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the following description, only parts necessary for understanding the operation according to the present invention will be described, and descriptions of other parts will be omitted so as not to distract from the gist of the present invention.

The present invention, in the manufacturing process of the liquid crystal display device, through the reflective sheet of the backlight unit disposed on the back of the liquid crystal panel to irradiate light to the liquid crystal panel produced through the array process and the cell process to the back of the backlight unit A test apparatus and method for a backlight unit for a liquid crystal display device capable of easily and automatically measuring the luminance of leakage light are proposed. The backlight unit may include a light source for emitting light, a light guide plate spaced apart from the side of the light source, and transmitting light from the light source to the liquid crystal panel, a lamp reflector surrounding the light source, and a rear surface of the light guide plate. A reflective sheet for returning the light emitted to the back of the light guide plate back to the light guide plate, and a diffusion sheet, a prism sheet, and a protective sheet sequentially installed on the front surface of the light guide plate are laminated and assembled in the mold frame.

Next, a test apparatus for a backlight unit according to a first embodiment of the present invention will be described with reference to FIG. 1.

FIG. 1 is a diagram schematically illustrating a structure of a test apparatus for measuring luminance of light leaking to a rear surface of a backlight unit through a reflective sheet of a backlight unit.

Referring to FIG. 1, the test apparatus of the backlight unit includes a detector 150, a level detector 160, a controller 170, and a notification unit 180. When the components of the above-described backlight unit 10 are assembled through the assembly process system, the backlight unit 10, which is moving the assembly process system through the conveyor belt, displays the brightness of the light leaking to the back through the reflective sheet. It is placed on the table 100 for measurement. The table 100 provides a predetermined space for the backlight unit 10 to be positioned thereon, and includes one or more fixing parts 200 for fixing the backlight unit 10. Here, the fixing part 200 serves to fix the backlight unit 10 on the table 100 by adsorbing the backlight unit 10, and preferably, the lower edges of both sides of the backlight unit 10 are fixed. Two fixtures 200 are provided for adsorption. In addition, the fixing part 200 can be moved according to the size of the backlight unit 10 by the guide groove provided in the table 100, and is fixed at a predetermined position after the movement.

When the backlight unit 10 is fixedly disposed on the table 100 as described above, the power supply unit 15 supplies power to the backlight unit 10. The light source of the backlight unit 10 emits light by the supplied power, and thus the backlight unit 10 irradiates the surface light upwardly, that is, upwardly, from the light emitted from the light source. At this time, the back of the backlight unit 10, that is, the sensing unit 150 disposed in the downward direction detects the brightness of light leaking to the back of the backlight unit 10 through the reflective sheet of the backlight unit 10.

Here, the sensing unit 150 is preferably composed of a photodiode, the photodiode detects the brightness of light leaked to the back of the backlight unit 10 to generate a voltage of a predetermined level by the photovoltaic effect. Accordingly, the photodiode, that is, the sensing unit 150 outputs voltages of different levels according to the brightness of light leaked to the back of the backlight unit 10 through the photovoltaic effect. The table 100 imparts a dark room effect to the rear surface of the backlight unit 10 in order to accurately measure the brightness of light leaking to the rear surface of the backlight unit 10, and the mold frame of the backlight unit 10 is the sensing unit. It is provided with a hole so that 150 is inserted.

As described above, the sensing unit 150 senses the brightness of light leaking to the rear surface of the backlight unit 10, and the sensing unit 150 outputs a voltage that varies according to the brightness of the light. The level detector 160 detects a voltage level that varies according to the brightness of light, and transmits the detected voltage level to the controller 170. The controller 170 determines whether the voltage level detected through the level detector 160 is a level of a reference range preset by the test apparatus user. That is, the controller 170 presets the reference range based on the upper limit value and the lower limit value input by the user, and determines whether the detected voltage level exceeds, falls below, and falls within the reference range. According to the determination result, the controller 170 transmits signals of different levels to the notification unit 180. In addition, the controller 170 includes a display unit 175, and the display unit 175 numerically represents the brightness of light through the detected voltage level.

The notification unit 180 notifies the user of the determination result of the control unit 170 through a signal received from the control unit 170, that is, a different level of notification signal according to the determination result of the control unit 170. Here, the notification unit 180 includes three notification lamps 182, 184, 186, and a speaker 188, and turns on one notification lamp according to signals of different levels transmitted by the controller 170. In addition, the notification unit 180 outputs different sound signals according to signals of different levels transmitted from the control unit 170 through the speaker 188. In other words, when the detected voltage level exceeds the reference range, the notification unit 180 turns on only the R notification lamp 182, and when it is less, turns on only the G notification lamp 184, and when it is within the range. Turn on only B notification light (186). When the R notification light 182 is turned on, the user can see that light is leaked excessively to the back of the backlight unit, so that the backlight unit is assembled to the required number of reflective sheets or less. In addition, when the G notification lamp 184 is turned on, the user may be aware that light leakage is less than a reference to the rear surface of the backlight unit, and thus the user may be assembled more than the number of reflection sheets required by the backlight unit. In addition, when the B notification light 186 is turned on, the user can see that the reflective sheet is properly assembled to the backlight because the light leakage is appropriate to the back of the backlight unit. In addition, the notification unit 180 outputs different sound signals corresponding to the notification lights turned on through the speaker 188 as described above. Therefore, the user can numerically know the brightness of light leaking to the back of the backlight unit 10 through the display unit 175 of the controller 170, and the backlight unit (not shown) by the notification signal output from the notification unit 180. 10) can be easily determined.

Next, a test method of the backlight unit according to the first embodiment of the present invention will be described with reference to FIG. 2.

FIG. 2 is a flowchart illustrating a test procedure for measuring the brightness of light leaking through the reflective sheet of the backlight unit to the back of the backlight unit.

Referring to FIG. 2, in operation 250, the sensing unit 150 senses the brightness of light leaking to the back of the backlight unit, and outputs voltages of different levels according to the brightness of light detected using the photovoltaic effect. . The voltage level that varies according to the brightness of the light is detected by the level detector 160 in step 260, and in step 270, the controller 170 determines whether the detected voltage level is a level within a reference range preset by the user. . The reference range is preset based on the upper limit value and the lower limit value input by the user, and it is determined whether the voltage level detected in step 270 is above, below, or within the reference range. In operation 280, the notification unit 180 outputs notification signals of different levels according to the determination result of operation 270.

As described above, according to the first embodiment of the present invention, the user places the backlight unit on a table to perform a test operation, so that the luminance of light leaking to the rear surface of the backlight unit through the reflective sheet can be measured without inverting the backlight unit. The user can quickly and accurately determine whether the backlight unit is defective.

Hereinafter, a test apparatus for a backlight unit for a liquid crystal display according to a second exemplary embodiment of the present invention will be described with reference to FIGS. 3 to 7.

As shown in FIGS. 3 to 7, a test apparatus for a backlight unit for a liquid crystal display according to a second exemplary embodiment of the present invention includes a table 100, a fixing unit 200, a light receiving unit 300, and a controller. 400. In the test apparatus of the present invention, the backlight unit 10 placed on the table 100 is fixed by the fixing unit 200, and the brightness of light of one surface of the backlight unit 10 facing the table 100 is fixed. Is measured by the light receiving unit 300, and the luminance of the measured light is input to the control unit 400 and configured to determine whether the backlight unit 10 is defective. In addition, the test apparatus of the present invention may further include a display unit 410 indicating the measured brightness of the light as a numerical value, and may further include an alarm unit 420 for notifying the user of whether the product is determined by the controller. have.

Referring to FIG. 3, the table 100 provides a space in which the backlight unit 10 is placed, and is formed in a flat plate shape and is fixed to the bottom plate 130 by the hinge device 500 to adjust tilt. This is possible, and the fixing part 200 and the light receiving part 300 are mounted at a predetermined position. The bottom plate portion 130 is a part in contact with an unshown structure on which the test apparatus according to the present embodiment is placed.

3 and 4, the fixing part 200 is fixed to prevent the backlight unit 10 placed on the table 100 from flowing. Preferably, the fixing unit 200 surrounds the bottom edges of both sides of the backlight unit 10. Two fixing parts are provided. That is, the fixing part 200 includes a horizontal part 210 having a surface facing the bottom surface 10a of the backlight unit 10 and a surface facing the side surface 10b of the backlight unit 10. The vertical part 220 is formed integrally, and two fixing parts are installed on the table 100 to form a mutually symmetrical structure to surround and fix lower edges of both sides of the backlight unit 10. In addition, the fixing part 200 has a structure that is movable in the left and right directions of the table 100. That is, a pair of guide grooves 110 extending in the left and right directions are formed on both sides of the lower end of the table 100, and the fixing part 200 is coupled to the guide groove 110. The fixing part 200 is moved along the 110 and is fixed at a predetermined position. Therefore, the distance between the fixing parts 200 can be widened or narrowed according to the size of the backlight unit 10. On the other hand, the fixing part 200 is fixed by a bolt 230 (shown in FIG. 5) inserted through the guide groove 110 from the back of the table 100.

5 and 6, the light receiving unit 300 measures the brightness of the backlight unit 10 fixed to the table 100, and is a rear surface of the table 100 to be exposed to the surface of the table 100. It is mounted from the to measure the brightness of the backlight unit (10). In this case, the light receiving unit 300 is fixed by the auxiliary housing 310 installed in the table 100. Preferably, the light receiving unit 300 is composed of a photodiode.

Meanwhile, a cushion member 320 surrounding the light receiving portion 300 exposed to the surface of the table 100 is provided on the table 100, and the cushion member 320 is formed by the light receiving portion 300. When measuring the luminance of light, the light is brought into close contact with the rear surface of the backlight unit 10 placed on the table 100 to impart a dark room effect to the measurement area, whereby light generated by the gap between the backlight unit 10 and the table 100 is generated. The luminance error is prevented.

The auxiliary housing 310 is a circular cylindrical with both ends open, the upper end is coincident with the surface of the table 100, the lower end is installed to protrude to the rear side of the table 100, the fixed screw ( 311). Thus, the light receiving unit 300 is inserted through the lower end of the auxiliary housing 310, it is firmly fixed by tightening the fixing screw (311).

Recently, a liquid crystal display device adopts a system that automatically adjusts the brightness of a liquid crystal display device by measuring the brightness of the light at the back of the backlight unit. In the bottom mold frame of the backlight unit, sensing is performed to measure the brightness of the back light. A hole is formed

Referring to FIG. 3 again, the auxiliary housing 310 fixing the light receiving unit 300 is installed at a position corresponding to the sensing hole 11 so that the luminance of the back light may be maintained even when the backlight unit 10 is not inverted. Measurement is possible. That is, the positions of the fixing unit 200 and the light receiving unit 300 are determined according to the positional relationship between the lower edges of both sides of the backlight unit 10 and the sensing hole 710, so that the backlight unit 10 is formed by the fixing unit 200. ) Is fixed, the light receiving unit 300 is configured to match the sensing hole 710 provided in the bottom plate frame of the backlight unit (10).

3 and 7, the table 100 is connected to the bottom plate 130 by a hinge device 500 and configured to have a predetermined slope. As the table 100 is inclined as described above, the backlight unit 10 placed on the table 100 is brought into close contact with the fixing unit 200 by its own weight, thereby preventing the backlight unit 10 from flowing even with a small force. You can do it.

The hinge device 500 includes a hinge shaft 510 and a hinge frame 520. The hinge shaft 510 is provided at the lower end of the table 100 to provide a rotation shaft that becomes the rotation center of the table 100. The hinge frame 520 is installed on the bottom plate 130, and has a bearing 521 for supporting the hinge shaft 510. On the other hand, a support bar 530 is provided on the back side of the table 100 to be fixed to the table 100 rotating around the hinge axis 510 while maintaining a predetermined angle. Therefore, since the support bar 530 supports the table 100 between the bottom plate part 130 and the table 100, the table 100 is fixed while maintaining a predetermined inclination.

The controller 400 receives a lower limit value and an upper limit value of luminance, which is a standard for determining whether the backlight unit is defective, from the user, and receives the luminance of light measured by the light receiver 300, and then measures the luminance of light measured. It is determined whether the backlight unit is defective by checking whether the value falls within the range of the stored lower limit value and the upper limit value.

The display unit 410 provides a function of numerically representing the brightness of the light input to the control unit 400 so that the user can know the brightness of the corresponding backlight unit.

The alarm unit 420 provides a function of notifying the user of whether the backlight unit is defective by determining whether the backlight unit is defective by the controller 400. The alarm unit 420 emits sound to determine whether the backlight unit is defective. The notice may consist of a speaker or two lamps of different colors. The two lamps, when the corresponding backlight unit is determined to be defective, any one lamp is turned on to inform the user that the corresponding backlight unit is defective, and conversely, when the corresponding backlight unit is determined to be good, the other lamp is turned on to The user is informed that the backlight unit is good.

The control unit 400, the display unit 410, and the alarm unit 420 as described above are installed in the control box 450 fixed to the bottom plate 130 to perform each function.

In the second embodiment of the present invention described above, the user carries the backlight unit, which is carried on the conveyor, through the assembly process directly to the table to perform the test process, and the luminance of the back light can be measured without inverting the backlight unit. There is an advantage that it is possible to quickly and accurately determine whether the backlight unit is defective.

Hereinafter, a more automated test apparatus will be described through a third embodiment of the present invention.

8 to 10, the backlight test apparatus according to the third embodiment of the present invention includes a sensing unit 600, a stopper 700, a light receiving unit 800, a driver 900, and a controller. And 1000. In the test apparatus according to the third exemplary embodiment, when the backlight detection signal is generated by the sensing unit 600, the stopper 700 stops the backlight unit 10, which is transported on the conveyor 30, in the correct position, and receives the light receiving unit. In operation 800, the luminance of the stationary backlight unit 10 is measured, and the controller 1000 compares the luminance of the light measured by the light receiving unit 800 with two luminance values previously input by the user. It is configured to determine whether or not. In addition, the display unit indicating the measured brightness of the light may be further included, and an alarm unit for notifying the user of whether the product is defective by the control unit 1000 may be further included. The control unit, the display unit, and the alarm unit are the same as the display unit and the alarm unit of the second embodiment described above, and a detailed description thereof will be omitted.

Referring to FIG. 8, the sensing unit 600 is for detecting the progress of the backlight to be transported on the conveyor 30. The backlight unit provided on the side surface of the conveyor 30 is transported on the conveyor. When entering the front of the provided sensing unit 600, the detection signal is generated and transmitted to the control unit 1000.

The stopper 700 stops the backlight unit transported on the conveyor at a predetermined position when a detection signal generated by the sensing unit 600 is generated, and protrudes between the rollers 31 provided on the conveyor 30. So that it is provided at the bottom of the conveyor 30. The stopper 700 provided is lifted by the driving unit 900 when the detection signal generated by the sensing unit 600 is raised and protrudes to the upper portion of the rollers 31 to define the backlight unit 10 transferred by the conveyor 30. Will be stopped in position. Preferably, with the stop of the backlight unit 10 by the stopper 700, the operation of the conveyor 30 is temporarily stopped. When the luminance measurement of the stopped backlight unit 10 is completed, the operation is again performed to transfer the backlight. Done.

Referring to FIG. 9, the backlight unit 10 transported on the conveyor 30 is transported in a state in which the pallet 20 having the auxiliary sensing holes 21 is placed. The auxiliary sensing hole 21 communicates with the sensing hole 11 provided in the bottom plate mold frame of the backlight unit 10 and extends to the bottom surface of the pallet 20 so that the light receiving unit 800 is inserted into the auxiliary light receiving unit. A space for allowing the 800 to approach the sensing hole 11 is provided.

Referring back to FIG. 8, when the backlight unit 10 is stopped at the correct position by the stopper 700, the light receiving unit 800 measures the brightness of the light in proximity to the sensing hole 11 provided in the stopped backlight unit. It is provided at the lower end of the conveyor 30 to be.

The driving unit 900 includes first and second cylinders 910 and 920 for fixing the stopper 700 and the light receiving unit 800, respectively, and is installed at the lower end of the conveyor 30 to stopper 700 and the light receiving unit 800. Is moved). When the first cylinder 910 is connected to the stopper 700 to generate a backlight detection signal by the sensing unit 600, the stopper 700 moves upward to protrude between the rollers 31. The second cylinder 920 is connected to the light receiver 800 so that the light receiver 800 is inserted through the auxiliary sensing hole 21 of the pallet 20 to approach the sensing hole 11 of the backlight unit 10. Will move upward. These first and second cylinders 910 and 920 may be operated by hydraulic or pneumatic pressure.

The control unit 100 generates a signal for operating the driving unit 900 when a detection signal is generated by the sensing unit 600, and receives the luminance measured by the light receiving unit 800 to determine whether the corresponding backlight unit is defective. Done.

In the third embodiment of the present invention described above, the backlight unit, which is transported through the conveyor through the assembly process, is stopped using a stopper, the luminance of the stopped backlight unit is measured through the light receiving unit, and the controller receives the measured luminance. Since the backlight unit is determined to be defective through a series of automated processes for determining whether the backlight unit is defective, the luminance of the light can be measured without moving the backlight unit by an operator.

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by the equivalents of the claims.

The present invention as described above, by accurately measuring the brightness of the backlight unit automatically and quickly informs the user of whether or not the backlight unit, it is possible to improve the reliability and manufacturing yield of the backlight unit.

Claims (25)

delete In the test apparatus of the backlight unit for a liquid crystal display device, A detector disposed on a rear surface of the backlight unit and detecting a brightness of light leaking from the reflective sheet of the backlight unit; A level detector detecting a voltage level that varies according to the brightness of the detected light; A controller for determining whether the voltage level is a level of a reference range preset by a user; And And a notification unit outputting a notification signal according to the determination result of the control unit. And the sensing unit outputs different levels of voltages according to the brightness of light detected through the photovoltaic effect.  The method of claim 2, The control unit further comprises a display unit for numerically indicating the brightness of the light, the test apparatus of the backlight unit for a liquid crystal display device. The method of claim 2, The controller determines whether the voltage level is above, below, and within the reference range, and transmits a signal having a different level to the notification unit according to a result of the determination, wherein the backlight unit for the liquid crystal display device is tested. Device. The method of claim 4, wherein And the notification unit outputs different levels of notification signals according to the determination result of the control unit. In the test method of the backlight unit for a liquid crystal display device, Sensing brightness of light leaking from the reflective sheet of the backlight unit; Detecting a voltage level that varies in accordance with the sensed brightness of the light; Determining whether the voltage level is a level of a reference range preset by a user; And And outputting a predetermined notification signal according to the determination result. The method of claim 6, The determining may include determining whether the voltage level is above, below, and within the reference range. In the test apparatus of the backlight unit for a liquid crystal display device, A table on which the backlight unit is placed; At least one fixing part fixed to the backlight unit mounted on the table; A light receiving unit mounted on a rear surface of the table and exposed to the surface of the table to measure the brightness of the backlight unit; And And a controller configured to receive the measured luminance from the light receiving unit and compare the measured luminance with two luminance values previously input by the user to determine whether the backlight unit is defective. Testing device. The method of claim 8, And a display unit connected to the control unit to display numerically the luminance measured from the light receiving unit. The test unit of the backlight unit for the liquid crystal display device. The method of claim 8, And an alarm unit connected to the control unit to notify a user of a defect of a product. The method of claim 10, The alarm unit is a test device for a backlight unit for a liquid crystal display device, characterized in that consisting of a speaker for emitting sound. The method of claim 10, And the alarm unit is composed of two lamps having different colors so as to be turned on to indicate whether the backlight unit is defective or not, to indicate whether the backlight unit is good or bad. The method of claim 8, One end of the table is connected to the flat bottom plate by a hinge device, and a support bar supporting the table between the bottom plate and the table is provided to have a predetermined inclination. Test device of the unit. The method of claim 8, The fixing part is formed with a horizontal portion having a surface facing the bottom surface of the backlight unit, a vertical portion provided with a surface on the side of the backlight unit is integrally formed, And two fixing parts are provided to surround and fix the bottom and side surfaces of the backlight unit at both bottom edges of the backlight unit. The method of claim 14, And a pair of guide grooves extending in the left and right directions so that the two fixing parts are movable in the left and right directions of the table, the test device of the backlight unit for the liquid crystal display device. The method of claim 8, The table has a cylindrical shape with both ends open, the upper end of which is exposed to the surface of the table, the lower end of which protrudes toward the rear side of the table so that the light receiving part is inserted, and has a fixing screw for fixing the light receiving part inserted therein. An auxiliary housing further comprises a test apparatus for a backlight unit for a liquid crystal display device. The method of claim 8, The light receiving unit is a photodiode, the test device for a backlight unit for a liquid crystal display device. The method of claim 8, And when the backlight unit is fixed by the fixing unit, the light receiving unit is configured to coincide with a sensing hole provided in the bottom plate frame of the backlight unit. The method of claim 8, The table has a cushioning member that is in close contact with the rear surface of the backlight unit placed on the table and surrounds the light receiving unit exposed to the surface of the table to give a dark room effect to the measurement area when measuring the luminance by the light receiving unit. The test apparatus of the backlight unit for a liquid crystal display device further comprising. In the test apparatus of the backlight unit for a liquid crystal display device, A sensing unit provided to a conveyor to which the backlight unit passed through the assembly process is transferred to detect whether the backlight unit is in progress; A stopper for protruding forward of the backlight unit in the forward direction of the backlight unit when the backlight unit is detected by the sensing unit to stop the backlight unit at a predetermined position; A light receiving unit which moves closer to a sensing hole provided in the bottom plate frame of the backlight unit stopped by the stopper to measure the brightness of the backlight unit; A driving unit which fixes the stopper and the light receiving unit to the conveyor and operates the stopper and the light receiving unit; And And a controller configured to operate the driving unit based on the detection signal of the sensing unit, and determine whether the backlight unit is defective by comparing the luminance measured by the light receiving unit with two luminance previously input by the user. Test device for backlight unit for liquid crystal display. The method of claim 20, And an alarm unit connected to the control unit to notify a user of a defect of a product. The method of claim 21, The alarm unit is a test device for a backlight unit for a liquid crystal display device, characterized in that consisting of a speaker for emitting sound. The method of claim 21, And the alarm unit is composed of two lamps having different colors so as to be turned on according to whether the backlight unit is defective or not to indicate whether the backlight unit is good or bad. The method of claim 20, The backlight unit is disposed on the upper end, and further comprises a pallet having a secondary sensing hole in communication with the sensing hole provided in the bottom plate frame and extending to the bottom surface is inserted into the light receiving unit. Testing device. The method of claim 20, The driving unit is connected to the stopper, the first cylinder is installed on the lower end of the conveyor to project the stopper between the transfer roller provided in the conveyor, And a second cylinder connected to the light receiving unit and installed in the lower end of the conveyor to raise the light receiving unit closer to the sensing hole.

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