JP2014096505A - Backlight and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device including backlight using a plurality of linear light sources as a light source, in which a boundary of chromaticity due to blue light is kept inconspicuous.SOLUTION: A method for manufacturing backlight includes the steps of: preparing an LED bar (linear light source) by mounting a plurality of LEDs linearly with an interval therebetween, the LEDs emitting synthetic light of blue light and light having a longer wavelength than the blue light through a combination of an LED chip emitting the blue light and a phosphor excited by the blue light to emit the light having a longer wavelength (a step P1); combining a plurality of the LED bars so that a peak wavelength difference, which is a difference of average peak wavelength between adjacent LED bars, is equal to or less than a specified value, the average peak wavelength being an average of peak wavelengths of blue light emitted from the LEDs in the LED bar (step P2); and joining the combined LED bars so as to be aligned in a straight line and to be assembled in a light guide plate (step P3).

Description

  The present invention relates to a backlight including a linear light source having a plurality of LEDs and a method for manufacturing the backlight.

  In recent years, backlights using LEDs having a long life and low power consumption as a light source have become widespread as backlights for liquid crystal display devices. A white LED is usually used for such a backlight. The white LED is generally configured by combining a blue LED and a phosphor. In such a white LED, white light is obtained by mixing the blue light emitted from the blue LED chip and the light emitted when the phosphor is excited by the blue light. For example, in a white LED using a green phosphor and a red phosphor as a phosphor, green light and red light obtained by exciting the green phosphor and the red phosphor with blue light are mixed with blue light. I get white light.

  In order to use such a white LED for a backlight, a direct type backlight or an edge light type backlight is applied. In the direct type backlight, each white LED directly irradiates the back surface of the liquid crystal panel. On the other hand, the edge light type backlight makes the light of the white LED enter from the side end of the light guide plate, emits the light from the exit surface of the light guide plate, and irradiates the back surface of the liquid crystal panel.

  Among these, in the edge light type backlight, normally, a plurality of white LEDs are arranged at the side end of the light guide plate. For this reason, for example, the white LED is mounted on a substrate or the like in a state of being linearly arranged along the side end portion of the light guide plate so as to be easily incorporated into a liquid crystal display device. (See, for example, FIG. 12 of Patent Document 1).

Special table 2011-504605 gazette (announced on February 10, 2011)

  Usually, a plurality of linear light sources as described above are combined. The following problems may occur in a backlight including a plurality of linear light sources combined in this way.

  As described above, a white LED used for a backlight is usually configured by combining a blue LED and a phosphor, so that even if the concentration of the phosphor is optimally determined, the phosphor has a desired concentration or It is very difficult to form the phosphor layer so as to be in an amount. For this reason, the density | concentration and quantity of a fluorescent substance do not become uniform between white LED at the time of manufacture. Moreover, since the characteristics of the blue LED and the light emitting layer vary among products, the peak wavelength of blue light varies among white LEDs. For this reason, since the balance of the light intensity of the excitation light of the phosphor and the blue light of the blue LED varies, the chromaticity varies among the white LEDs.

  For this reason, the white LED used for the linear light source ranks the peak wavelength of blue light into a predetermined range, and the white LED of the same rank is mounted on a single linear light source. The peak wavelength of blue light is classified into ranks having a range of 2.5 nm as shown in Table 1 below, for example. Moreover, the peak wavelength of blue light in the linear light source is obtained as an average of the peak wavelengths of blue light in all white LEDs mounted on the linear light source.

  If white LEDs of the same rank (single rank) are mounted on adjacent linear light sources, there is no difference in the peak wavelength of blue light between the two linear light sources. On the other hand, when white LEDs having different ranks are mounted on adjacent linear light sources, a difference occurs in the peak wavelength of blue light between the two linear light sources. In this case, if the difference in peak wavelength of blue light between both linear light sources is greater than 7.5 nm, the boundary of chromaticity due to blue light appears on the two linear light sources on the screen.

  For example, the difference in peak wavelength of blue light is 5.0 nm between a linear light source on which a white LED of rank “2” is mounted and a linear light source on which a white LED of rank “4” is mounted. So the chromaticity boundary is invisible. Moreover, since the difference in peak wavelength of blue light is 2.5 nm between the linear light source on which the white LED of rank 3 is mounted and the linear light source on which the white LED of rank “4” is mounted, The boundary of chromaticity is not visible. However, the difference in the peak wavelength of blue light is 7.5 nm between the linear light source on which the white LED of rank “1” is mounted and the linear light source on which the white LED of rank “4” is mounted. So you can see the boundary of chromaticity.

  The phenomenon in which the boundary of chromaticity as described above is visible appears more prominently in a region close to a linear light source in which light from both linear light sources is rarely mixed. For this reason, there is a disadvantage that the display color in the display image becomes non-uniform.

  The present invention has been made in view of the above problems, and an object thereof is to make a boundary of chromaticity due to blue light inconspicuous in a liquid crystal display device including a backlight using a plurality of linear light sources as a light source. It is in.

  In order to solve the above-described problem, a method for manufacturing a backlight according to one embodiment of the present invention includes an LED element that emits primary light and a secondary having a wavelength longer than that of the primary light excited by the primary light. A production process for producing a linear light source by mounting a plurality of LEDs emitting combined light of the primary light and the secondary light on a substrate in a linear interval by combining with a phosphor emitting light And a peak wavelength difference that is a difference between adjacent linear light sources of an average peak wavelength that is an average of peak wavelengths of the primary light emitted by the LEDs in the linear light source is equal to or less than a specified value. The method includes a combination step of combining a plurality of the linear light sources, and an integration step of joining the combined linear light sources so as to be aligned and incorporating them into the light guide plate.

  In order to solve the above-described problem, a backlight according to one embodiment of the present invention includes an LED element that emits primary light and secondary light having a wavelength longer than that of the primary light when excited by the primary light. A plurality of LEDs emitting combined light of the primary light and the secondary light by being combined with a phosphor that emits light are arrayed linearly at intervals and are joined together so as to be aligned with each other A linear light source, and a light guide plate that emits light emitted from the linear light source incident at least from one end side to the liquid crystal panel in a planar shape, and the plurality of linear light sources includes the LED in the linear light source. Are combined so that the peak wavelength difference, which is the difference between the adjacent linear light sources of the average peak wavelength, which is the average of the peak wavelengths of the primary light emitted from the light source, becomes a specified value or less. Yes.

  According to one embodiment of the present invention, there is an effect that it is possible to provide a backlight that can prevent a chromaticity boundary from being seen.

It is a perspective view which shows the structure of the liquid crystal display device common to each embodiment of this invention. It is a longitudinal cross-sectional view which shows the structure of LED used for the backlight in the said liquid crystal display device. It is a graph which shows the emission spectrum of said LED. It is a manufacturing process figure which shows the procedure of manufacture of the said backlight which concerns on Embodiment 1 of this invention. It is a block diagram which shows the structure of the direction LED bar combination apparatus which classifies the LED bar integrated in the said backlight. It is a flowchart which shows the procedure of the combination of the LED bar by the said LED bar combination apparatus. It is a figure which shows the range from which the average of a peak wavelength is calculated from the junction part of LED bar in the combination of the LED bar which concerns on the modification of Embodiment 1. FIG. It is a manufacturing process figure which shows the procedure of manufacture of the said backlight which concerns on Embodiment 2 of this invention. It is a figure which shows the arrangement pattern of LED in the LED bar used for manufacture of the backlight which concerns on Embodiment 2. FIG. It is a figure which shows the other arrangement pattern of LED in the LED bar used for manufacture of the backlight which concerns on Embodiment 2. FIG.

[Liquid Crystal Display]
First, a configuration of a liquid crystal display device common to each embodiment according to the present invention will be described below.

[Configuration of liquid crystal display device]
FIG. 1 is a perspective view showing a schematic configuration of a liquid crystal display device 1 according to each embodiment.

  As shown in FIG. 1, the liquid crystal display device 1 includes a liquid crystal panel 2 and a backlight 3.

  The liquid crystal panel 2 is filled with liquid crystal between two transparent substrates facing each other, and the transmittance of light from the backlight 3 is changed by changing the alignment state of the liquid crystal in units of pixels configured in a matrix. change. Further, the liquid crystal panel 2 has a color filter 4 disposed on the display surface side. In the color filter 4, filters for each color of red (R), green (G), and blue (B) are formed for each of the three sub-pixels constituting each pixel. When light passes through each filter, the light of the color of each filter can be emitted. In the liquid crystal panel 2, based on the light color component ratio of red (R), green (G), and blue (B) corresponding to the color of each pixel determined for each display image, transmission of the liquid crystal layer corresponding to the sub-pixel is performed. By adjusting the rate individually, each pixel is displayed in a color to be displayed.

  The backlight 3 is an edge light type backlight that is disposed on the back side of the liquid crystal panel 2 and irradiates light on the entire surface of the liquid crystal panel 2. The backlight 3 includes a light guide plate 5 and LED bars 6 and 7.

  The LED bars 6 and 7 are linear light sources, and are disposed adjacent to each other at an end of the light guide plate 5 where light on at least one side is incident. The LED bars 6 and 7 are arranged on the lower side in the example shown in FIG. The LED bar 6 is disposed on the right side of the liquid crystal display device 1 and the LED bar 7 is disposed on the left side.

  The LED bars 6 and 7 are each composed of a plurality of LEDs 9 and a substrate 8. In addition, the LED bars 6 and 7 have peak wavelengths so that the light emitted from the liquid crystal panel 2 does not show a chromaticity boundary based on the difference in peak wavelength of blue light in the light of the LED bars 6 and 7. They are combined so that the difference is not more than the specified value of 7.5 nm.

  In addition, the peak wavelength of the blue light of LED bar 6 and 7 is calculated | required as an average of the peak wavelength of the blue light which LED9 mounted in LED bar 6 and 7, respectively emits.

  The substrate 8 is formed in an elongated strip shape (linear shape), and has a width that is slightly wider than the outer size (width) of the LED 9. In the substrate 8, printed wiring (not shown) for supplying power to the LEDs 9 is formed on the mounting surface on which the LEDs 9 are mounted. Further, a positive electrode terminal and a negative electrode terminal (not shown) connected to the printed wiring are provided at both ends or one end of the substrate 8. The LED 9 is fed by connecting a wiring for power feeding from the outside to the positive terminal and the negative terminal.

  The LED 9 is a white LED and is mounted on the substrate 8 at a predetermined interval so as to emit light toward the light guide plate 5 side. As will be described later, the white LED includes a blue LED and a red phosphor and a green phosphor that are excited by the blue light of the blue LED.

  The light guide plate 5 has a structure in which light can be extracted from each part of the light emitting surface so that linear light incident from the LED bars 6 and 7 is emitted in a planar shape.

  In the liquid crystal display device 1, the two LED bars 6 and 7 are used as the light source of the backlight 3, but three or more LED bars may be used.

  The LED bars 6 and 7 are disposed on the lower side (lower side) of the light guide plate 5, but are not limited thereto, and may be disposed on the left and right sides or the upper side of the liquid crystal panel 2. Alternatively, a pair of LED bars similar to the LED bars 6 and 7 may be provided on the two opposite sides of the light guide plate 5.

  Further, in the liquid crystal display device 1, good results are obtained in the following embodiments, particularly under the following conditions.

LED9 size: 4-8mm x 1-4mm
LED 9 pitch in LED bars 6 and 7: 0.5 to 2.0 cm
LED bars 6 and 7 length: 30 to 100 cm (for screen size 31 to 100 inches of liquid crystal display device 1)
[Configuration of LED]
FIG. 2 is a longitudinal sectional view showing a configuration of the LED 9 as the LED 9 used in the backlight 3 described above. FIG. 3 is a graph showing an emission spectrum of the LED 9.

  The LED 9 shown in FIG. 2 is a white LED and includes a frame 11, an LED chip 12, a lead frame 13, a wire 14, a resin 15, and phosphors 16 and 17.

  The frame 11 is disposed on the lead frame 13. The frame 11 is made of a nylon material and has a recess 11a. The inclined surface of the recess 11a is formed as a reflective surface that reflects the emitted light of the LED chip 12. The reflecting surface is preferably formed of a metal film containing silver or aluminum in order to efficiently extract the emitted light from the LED chip 12.

  The lead frame 13 is insert-molded in the frame body 11. The upper end portion of the lead frame 13 is divided and formed, and a part of the lead frame 13 is exposed at the bottom surface of the concave portion 11 a of the frame body 11. The lower end portion of the lead frame 13 is cut to a predetermined length and is bent along the outer wall of the frame body 11 to form an external terminal.

  The LED chip 12 (LED element) is, for example, a GaN-based semiconductor light-emitting element having a conductive substrate, and a bottom electrode is formed on the bottom surface of the conductive substrate, and an upper electrode is formed on the opposite surface. The outgoing light (primary light) of the LED chip 12 is blue light in the range of 430 to 480 nm, and has a peak wavelength near 450 nm. The LED chip 12 is die-bonded with a conductive brazing material on one side of the upper end portion of the lead frame 13 exposed on the bottom surface of the recess 11a. Further, in the LED chip 12, the upper electrode and the other side of the upper end portion of the lead frame 13 are wire-bonded by a wire 14. Thus, the LED chip 12 is electrically connected to the lead frame 13.

  The resin 15 seals the recess 11a by filling the recess 11a. Further, since the resin 15 is required to have high durability with respect to primary light having a short wavelength, a silicone resin is preferably used.

  The phosphors 16 and 17 are dispersed in the resin 15. The phosphor 16 is a green phosphor that emits green secondary light having a longer wavelength than the primary light (peak wavelength is 500 nm or more and 550 nm or less), and is made of, for example, a Eu-activated β sialon phosphor material. On the other hand, the phosphor 17 is a red phosphor that emits red light having a longer wavelength than the primary light (peak wavelength is 600 nm or more and 780 nm or less). For example, the phosphor 17 is made of a phosphor material mixed with CaAlSiN3: Eu. Become. By using such phosphors 16 and 17, a three-wavelength type LED 9 having good color rendering properties can be obtained.

  In the LED 9 configured as described above, as the primary light emitted from the LED chip 12 passes through the resin 15, a part thereof excites the phosphors 16 and 17 and is converted into secondary light. The outgoing light (combined light) in which the primary light and the secondary light are mixed is radiated to the outside as substantially white light.

  FIG. 3 is a graph showing an emission spectrum of the LED 9, where the vertical axis represents intensity (arbitrary unit) and the horizontal axis represents wavelength (nm).

  As shown in FIG. 3, the emission spectrum of the three-wavelength type LED 9 is distributed so as to have peaks in blue, green and red, and the peak of blue light is the largest. The LED 9 uses specific phosphors 16 and 17 that are excited by blue light having a wavelength in the range of 430 to 480 nm in the primary light and emit light with high efficiency. Thereby, LED9 which has the spectral characteristic adjusted according to the transmission characteristic of the liquid crystal display device 1 can be obtained.

  In the liquid crystal display device 1, the phosphors included in the LEDs 9 are a green phosphor and a red phosphor, but are not limited thereto. For example, the LED 9 may include a yellow phosphor that is excited by blue light of a blue LED, instead of the green phosphor and the red phosphor. Thereby, pseudo white can be obtained by mixing the blue light of the blue LED and the yellow light of the yellow phosphor.

[Embodiment 1]
A method for manufacturing the backlight 3 according to Embodiment 1 of the present invention will be described with reference to FIGS.

[Manufacture of backlights]
FIG. 4 is a manufacturing process diagram showing a procedure for manufacturing the backlight 3 according to this embodiment.

  In the present embodiment, as shown in FIG. 4, first, LED bars (LED bar components) used as the LED bars 6 and 7 are manufactured (step P1).

  In the process P1, the LED 9 is mounted on the mounting surface of the substrate 8 at a predetermined interval using an LED mounting device (not shown). As shown in Table 1, the mounted LEDs 9 are not classified into ranks based on the peak wavelength of blue light (hereinafter simply referred to as “peak wavelength”). For this reason, the LED 9 selected without distinguishing the peak wavelength is used for mounting. Therefore, the manufactured LED bar parts are mounted with a mixture of LEDs 9 having different peak wavelengths.

  In the LED mounting apparatus, first, cream solder is printed on the substrate 8, and the LED 9 held on the tape is removed from the tape and placed on the substrate 8. The cream solder is melted by reflowing the substrate 8, and the LED 9 is joined to the substrate.

  Subsequently, a combination of two LED bar parts used as the LED bars 6 and 7 is determined from the LED bar parts manufactured as described above (step P2).

  In step P2, the LED bar parts are classified into ranks based on the average peak wavelength of each LED bar part, and as a combination of two LED bar parts having a peak wavelength difference of 7.5 or less based on the rank. The LED bars 6 and 7 are determined. This process is performed using the LED bar combination device 21 (see FIG. 5) described later. The LED bar combination device 21 will be described in detail later.

  Further, the combined LED bars 6 and 7 are incorporated into the light guide plate 5 to produce the backlight 3 (process P3).

  In step P3, as shown in FIG. 1, the LED bars 6 and 7 are arranged on one end side of the light guide plate 5 in a state of being joined so as to be aligned in a straight line.

  The backlight 3 is completed through the processes P1 to P3 as described above.

[LED combination device]
FIG. 5 is a block diagram showing the configuration of the LED bar combination device 21.

  The LED bar combination device 21 shown in FIG. 5 classifies the LED bar parts manufactured in the above-described process P1 into ranks based on peak wavelengths, and combines LED bar parts with ranks where the difference in peak wavelengths is 7.5 nm or less. It is a device to decide. The LED bar combination device 21 includes a memory 22, a storage unit 23, a display unit 24, and an arithmetic processing unit 25 in order to classify and combine LED bar components.

  Further, the LED bar combination device 21 performs rank classification and LED bar component combination based on the LED bar component characteristic measurement values given from the LED characteristic measurement device 31. The LED characteristic measuring device 31 is a device that measures the peak wavelength of the LED bar component, and measures and outputs the peak wavelength of each LED 9 with all the LEDs 9 of the LED bar component emitting light.

  The LED characteristic measurement device 31 is configured to be provided outside the LED bar combination device 21, but may be provided as a part of the LED bar combination device 21.

<Configuration of memory, storage unit and display unit>
The memory 22 temporarily stores the LED bar component characteristic measurement values (peak wavelengths of all the LEDs 9 in each LED bar component) from the LED characteristic measuring device 31, or calculation data generated by calculation processing by the calculation processing unit 25. It is a volatile memory that temporarily stores. The characteristic measurement values are stored in the memory 22 in a state in which the codes assigned to the LED bar parts are associated with each other so that the LED bar parts can be identified with respect to the total number of LED bar parts to be classified.

  The storage unit 23 is a storage device that stores the result of the combination of the LED bar parts obtained by the arithmetic processing of the arithmetic processing unit 25, and includes a hard disk device or the like.

  The display unit 24 is a display device for displaying the result of the above combination.

<Configuration of processing unit>
The arithmetic processing unit 25 classifies the LED bar parts into ranks based on the peak wavelength from the LED characteristic measuring device 31, and performs a process of combining the LED bar parts based on the classified ranks. The arithmetic processing unit 25 includes an average calculation unit 26, a wavelength rank classification unit 27, and a combination determination unit 28 in order to realize the above processing.

  The average calculation unit 26 calculates the average (average peak wavelength) of the peak wavelengths of all or some of the LEDs 9 in the LED bar components given from the LED characteristic measurement device 31 stored in the memory 22, thereby Find the peak wavelength of the component. The average calculating unit 26 stores the obtained peak wavelength of the LED bar component in the memory 22 in a state in which the codes assigned to the LED bar components are associated with each other so that the LED bar components can be specified.

  The wavelength rank classification unit 27 classifies each LED bar component into a rank based on the peak wavelength of the LED bar component stored in the memory 22. The ranks used here are the same ranks “1” to “4” as the ranks used for the LEDs shown in Table 1 above. This wavelength rank classification | category part 27 is memorize | stored in the memory 22 in the state matched with the code | cord | chord of the LED bar component.

  The combination determination unit 28 determines the LED bars 6 and 7 that are combinations of LED bar parts with ranks such that the difference in peak wavelength is 7.5 or less, and causes the storage unit 23 to store them. In addition, the combination determination unit 28 displays the combination result of the LED bars 6 and 7 stored in the storage unit 23 together with the code.

<Realization form of arithmetic processing unit>
Each block of the average calculation part 26, the wavelength rank classification | category part 27, and the combination determination part 28 in the arithmetic processing part 25 is implement | achieved by software (LED classification program) using CPU as follows. That is, the LED classification program causes the computer to function as the LED bar combination device 21 (the average calculation unit 26, the wavelength rank classification unit 27, and the combination determination unit 28).

  Or each said block may be comprised by a hardware logic, and may be implement | achieved by the process by the program using DSP (Digital Signal Processor).

  The program code (execution format program, intermediate code program, source program) of the above software may be recorded on a recording medium recorded so as to be readable by a computer. The object of the present invention can also be achieved by supplying the recording medium to the LED bar combination device 21 and reading and executing the program code recorded on the recording medium by the CPU.

  Examples of the recording medium include magnetic tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and optical disks such as CD-ROM / MO / MD / BD / DVD / CD-R. Can be used. In addition, as the recording medium, a card system such as an IC card (including a memory card) / optical card or a semiconductor memory system such as a mask ROM / EPROM / EEPROM (registered trademark) / flash ROM can be used. .

  Further, the LED bar combination device 21 may be configured to be connectable to a communication network, and the program code may be supplied via the communication network. The communication network is not particularly limited. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication. A net or the like is available. Further, the transmission medium constituting the communication network is not particularly limited. For example, even in the case of wired such as IEEE 1394, USB, power line carrier, cable TV line, telephone line, ADSL line, etc., infrared rays such as IrDA and remote control, Bluetooth ( (Registered trademark), 802.11 wireless, HDR, mobile phone network, satellite line, terrestrial digital network, and the like can also be used. The present invention can also be realized in the form of a computer data signal embedded in a carrier wave in which the program code is embodied by electronic transmission.

[Processing by LED bar combination device]
The determination of the combination of the LED bars 6 and 7 by the LED bar combination device 21 will be described with reference to the flowchart of FIG. FIG. 6 is a flowchart showing the combination procedure.

  As shown in FIG. 6, first, the peak wavelengths from the LED characteristic measuring device 31 are acquired for the total number of LEDs 9 included in the LED bar component, and stored in the memory 22 (step S1). Next, the average of the acquired peak wavelengths is calculated for each LED bar component (step S2).

  Further, based on the calculated peak wavelength, the LED bar parts are classified into any of ranks “1” to “4” (step S3). Then, based on the classified rank, a combination of LED bar parts is determined (step S4). At this time, when one LED bar part is specified, the LED bar part having a difference in peak wavelength of 7.5 nm or less with respect to the peak wavelength of this LED bar part is stored in the code and peak wavelength stored in the memory 22. Selected based on.

  In this way, the combination of the two LED bars 6 and 7 having a peak wavelength difference of 7.5 or less is determined.

[Modification]
Subsequently, a modification of the present embodiment will be described with reference to FIG.

  FIG. 7 is a diagram illustrating a range in which the average of the peak wavelengths is calculated from the joint portion of the LED bars 6 and 7.

  In this modification, as shown in FIG. 7, when determining the combination of the LED bars 6, 7, the peak for the LED 9 arranged in a predetermined range D from the joint portion (joint end portion) of the LED bars 6, 7. Only the average of the wavelengths is used. This is due to the following reason. Generally, since the peak wavelength of each LED 9 hardly changes abruptly in the LED bar part, it is only necessary to measure the wavelength of the LED chip near the joint part of the LED bar part that causes the chromaticity boundary. In addition, it is necessary not to cause a chromaticity boundary so that the average of the peak wavelengths in the vicinity of the joint portion is close between the LED bar components rather than the average of the entire peak wavelengths of the LED bar components.

  The range D varies depending on the lengths of the LED bars 6 and 7, but is preferably 10 to 20 cm.

  For this reason, the LED characteristic measuring device 31 measures the peak wavelength only for the LEDs 9 arranged in the range D for each LED bar component, and provides the LED bar combining device 21 with the peak wavelength. In the LED bar combination device 21, the average calculation unit 26 calculates the average peak wavelength for each LED bar component based on the peak value acquired from the LED characteristic measurement device 31. Thereby, the wavelength rank classification unit 27 classifies the LED bar parts into ranks based on the average of the peak wavelengths, and the combination determination unit 28 determines the difference in peak wavelengths based on the ranks thus classified. The combination of LED bar parts that is 7.5 nm or less is determined.

[Effect of the embodiment]
As described above, in the present embodiment, the LED bar combination device 21 is used to determine the combination of the LED bars 6 and 7 having a peak wavelength difference of 7.5 nm or less and incorporate the combination into the backlight 3. Thereby, it can avoid that the boundary of chromaticity by the difference of the peak wavelength of LED bar 6 and 7 is seen.

  In the present embodiment, after mounting the LED 9, the peak wavelength of the LED bar component is calculated, and the combination of the LED bars 6 and 7 is determined based on the peak. Thus, the LED bar parts need only be managed by rank, and the LED 9 need not be managed by rank. As described above, since the number of management objects is greatly reduced, the management of parts can be simplified.

  Moreover, in the modification, the average of the peak wavelengths of the LEDs 9 arranged in the range D from the joint portion of the LED bars 6 and 7 is calculated as the peak wavelength of the LED bar parts instead of the total number of LEDs 9 of the LED bar parts. Thus, even if the combination of the LED bars 6 and 7 is determined not by the average of the peak wavelengths of all the LEDs 9 of the LED bar component but by the average of the peak wavelengths of some of the LEDs 9, the peak wavelengths of the LED bars 6 and 7 It is possible to avoid seeing the chromaticity boundary due to the difference between the two. Therefore, the number of LEDs 9 that measure the peak wavelength in the LED bar component is greatly reduced relative to the total number of LEDs 9 in the LED bar component. Therefore, since the measurement time of the peak wavelength in the LED bar part is significantly shortened, the time required for manufacturing the backlight 3 can be shortened.

[Embodiment 2]
Another embodiment according to the present invention will be described below with reference to FIGS.

  In the present embodiment, components having functions equivalent to those of the components in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

[Manufacture of backlights]
FIG. 8 is a manufacturing process diagram showing a procedure for manufacturing the backlight 3 according to this embodiment.

  In the present embodiment, as described below, unlike the first embodiment in which the LED bars 6 and 7 are manufactured using the LEDs 9 that are not classified into ranks at the peak wavelengths, the LEDs 9 that are classified into ranks at the peak wavelengths in advance. LED bars 6 and 7 are produced using

  As shown in FIG. 8, first, the LEDs 9 used for the LED bars 6 and 7 are selected from the LEDs 9 classified into the ranks shown in Table 1 with respect to the peak wavelength according to the rank, and the array of the selected LEDs 9 is selected. Is determined in accordance with a specified mounting rule (process P11).

  In the process P11, prior to the mounting of the LEDs 9 performed in the subsequent process P12, the mounting rule for excluding (prohibiting) unifying all the LEDs 9 into a single rank of rank “1” or rank “4” is satisfied. The LED 9 is selected. In step P11, the array of the selected LEDs 9 is determined as the array pattern of the LEDs 9 in the LED bars 6 and 7 according to the mounting rule.

  A specific example of the array pattern of the LEDs 9 that conforms to this mounting rule will be described in detail later.

  Subsequently, the LED bar used as LED bar 6 and 7 is produced (process P12).

  In step P12, the LED 9 is mounted on the mounting surface of the substrate 8 at a predetermined interval using the LED mounting device, as in step P2 (see FIG. 4) of the first embodiment. On the tape attached to the LED mounting apparatus, the LEDs 9 previously selected in the process P11 are held so as to be arranged in accordance with the mounting rules.

  Further, similarly to the configuration P3 of the first embodiment, the combined LED bars 6 and 7 are incorporated into the light guide plate 5 to produce the backlight 3 (step P13).

  The backlight 3 is completed through the processes P1 to P3 as described above.

[LED arrangement pattern]
FIG. 9 is a diagram showing a first arrangement pattern of the LEDs 9 in the LED bars 6 and 7 used for manufacturing the backlight 3. FIG. 10 is a diagram showing a second arrangement pattern of the LEDs 9 in the LED bars 6 and 7 used for manufacturing the backlight 3.

  9 and 10, the numbers described in “LED arrangement” represent the ranks of the LEDs 9 arranged on the LED bars 6 and 7, respectively. 9 and 10, the numerical value described in “rank average” represents the average rank of the LEDs 9 in the LED bars 6 and 7. Further, in FIG. 9 and FIG. 10, the numerical value described in “rank average difference” represents the average difference in rank between the LED bars 6 and 7.

  In addition, the 1st and 2nd arrangement pattern of LED9 demonstrated below is an arrangement pattern in case eight LED9 is each mounted in LED bar 6 and 7 for convenience. However, it goes without saying that the number of LEDs 9 mounted on the LED bars 6 and 7 is not limited to eight.

  Further, in the first and second arrangement patterns, the arrangement of the LEDs 9 in the LED bars 6 and 7 may be switched.

  Here, in the first and second arrangement patterns described below, the difference between the average rank of the LEDs 9 in the LED bar 6 and the average rank of the LEDs 9 in the LED bar 7 is 2.0 or less. The arrangement of the LEDs 9 is determined. This is because when the rank difference is 2.0 or less, as described below, the peak wavelength difference, which is a condition for seeing the boundary of chromaticity, does not become larger than 7.5 nm.

  Here, the average difference of the ranks of the LEDs 9 in the LED bars 6 and 7 will be described.

  Table 2 shows the maximum peak wavelength difference (maximum difference) and the minimum difference (minimum difference) between the two ranks. The minimum difference is given by the difference between the minimum value of the peak wavelength of the smaller rank of the two ranks to be compared and the maximum value of the peak wavelength of the larger rank. On the other hand, the maximum difference is given by the difference between the maximum value of the peak wavelength of the smaller rank of the two ranks to be compared and the minimum value of the peak wavelength of the larger rank. The wavelength difference average is an average of the maximum difference and the minimum difference.

  For example, in the comparison between rank “1” and rank “2” where the rank difference is 1, the minimum and maximum differences are obtained as follows. The minimum difference becomes 0 by the difference (449.0-449.0) between the minimum value of the peak wavelength of rank “1” and the maximum value of the peak wavelength of rank “2”. On the other hand, the maximum difference is 5.0 due to the difference (451.5-446.5) between the maximum value of the peak wavelength of rank “1” and the minimum value of the peak wavelength of rank “2”. Therefore, in this case, the average wavelength difference is 2.5.

  As shown in Table 2, when the difference in rank is 0 to 2, the maximum difference in peak wavelength is 7.5 nm or less. Therefore, it is possible to combine the ranks of the LEDs 9 that cause these rank differences between the LED bars 6 and 7. Yes (OK). On the other hand, when the rank difference is 3, the maximum difference in peak wavelength is greater than 7.5 nm. Therefore, combining the ranks of the LEDs 9 that cause a rank difference of 3 between the LED bars 6 and 7 has a chromaticity boundary. It is impossible to see (NG).

  For example, when all the LEDs 9 in any one of the LED bars 6 and 7 are in rank “1” and all the LEDs 9 in the other are in rank “4”, the rank difference is 3, so The difference in peak wavelength between 7 is greater than 7.5 nm. In this case, since the difference in the average rank between the LED bars 6 and 7 is 3, such a combination of the LEDs 9 of the ranks cannot be used. Therefore, in order to prevent the chromaticity boundary from being seen, the average difference between the ranks of the LEDs 9 in the LED bars 6 and 7 is set to 2.0 or less.

<First arrangement pattern>
As a rule of the first arrangement pattern for the LED bars 6 and 7 that conform to the mounting rules described above, it is considered that the rank average of the LEDs 9 in the LED bars 6 and 7 is set in a range of 1.5 to 3.5. It is done. In the case of this rule, no matter how the LED bars 6 and 7 in which the LEDs 9 are arranged are combined, the above-described mounting rule (the average difference between the ranks of the LED 9 in the LED bars 6 and 7 is 2.0 or less) Conform to the setting). Thereby, there is no restriction | limiting in particular about the combination of LED bar 6 and 7. FIG.

  The arrangement pattern of the LEDs 9 in the LED bars 6 and 7 is not particularly defined as long as it satisfies the condition that the rank average of the LEDs 9 is in the range of 1.5 to 3.5. However, more preferable is an arrangement pattern in which LEDs 9 of different ranks are arranged alternately. Specific examples thereof include combinations A1 to A18 of LED bars 6 and 7, as shown in FIG. In the first arrangement pattern, when the LED 9 of rank “1” or rank “4” is used for one of the LED bars 6, 7, the LED 9 of rank “2” or rank “3” is used for the other. Is stipulated.

  In the combinations A1 and A3, the LED 9 of rank “1” and the LED 9 of rank “2” are alternately arranged in the arrangement pattern of the LED bars 7. In the combinations A2 and A4, the LED 9 of rank “1” and the LED 9 of rank “3” are alternately arranged in the arrangement pattern of the LED bars 7. On the other hand, in the combinations A1 and A2, the LEDs 9 of rank “2” are all arranged in the LED bar 6 arrangement pattern. In the combinations A3 and A4, the LEDs 9 of rank “3” are all arranged in the arrangement pattern of the LED bars 6.

  In the combinations A5 and A7, the LED 9 of rank “4” and the LED 9 of rank “2” are alternately arranged in the arrangement pattern of the LED bars 7. In the combinations A6 and A8, the LED 9 of rank “4” and the LED 9 of rank “3” are alternately arranged in the arrangement pattern of the LED bars 7. On the other hand, in the combinations A5 and A6, the LEDs 9 of rank “2” are all arranged in the arrangement pattern of the LED bars 6. In the combinations A7 and A8, the LEDs 9 of all ranks “3” are arranged in the arrangement pattern of the LED bars 6.

  In the combinations A9 and A10, the LED 9 of rank “1” and the LED 9 of rank “2” are alternately arranged in the arrangement pattern of the LED bars 7. In the combinations A11 and A12, the LED 9 of rank “1” and the LED 9 of rank “3” are alternately arranged in the arrangement pattern of the LED bars 7. On the other hand, in the combinations A9 and A11, the LED 9 of rank “4” and the LED 9 of rank “2” are alternately arranged in the arrangement pattern of the LED bars 6. In the combinations A10 and A12, the LED 9 of rank “4” and the LED 9 of rank “3” are alternately arranged in the arrangement pattern of the LED bars 6.

  In the combinations A13 to A18, the LED 9 of rank “1” and the LED 9 of rank “4” are alternately arranged in the arrangement pattern of the LED bars 7, but the arrangement of the LEDs 9 in the arrangement pattern of the LED bars 6 is the next. Different.

  In the combination A13, the LEDs 9 of rank “2” are all arranged. In the combination A14, LEDs 9 of all ranks “3” are arranged. In the combination A15, the LED 9 with the rank “4” and the LED 9 with the rank “2” are alternately arranged. In the combination A <b> 16, the LED 9 with the rank “4” and the LED 9 with the rank “3” are alternately arranged. In the combination A17, the LED 9 with the rank “1” and the LED 9 with the rank “2” are alternately arranged. In the combination A18, the LED 9 with the rank “1” and the LED 9 with the rank “3” are alternately arranged.

  In the combination A13 to A18, the rank difference between the adjacent LEDs 9 in the LED bar 7 is 3, but since the ranks of all the LEDs 9 in the LED bar 7 are averaged, the chromaticity boundary between the adjacent LEDs 9 is visible. Absent.

  In the first arrangement pattern as described above, the average rank difference between the LED bars 6 and 7 is 2.0 or less.

<Second arrangement pattern>
As a rule of the second arrangement pattern for the LED bars 6 and 7 that conform to the mounting rules described above, an arrangement in which the average difference of the ranks of the LEDs 9 in the LED bars 6 and 7 is 2.0 or less can be considered. In the case of this rule, the arrangement pattern of the LEDs 9 in the LED bars 6 and 7 is not particularly limited. However, more preferable is an arrangement pattern in which LEDs 9 of different ranks are arranged alternately. Specific examples thereof include combinations B1 to B13 of LED bars 6 and 7, as shown in FIG.

  In the combinations B1 to B4, in the arrangement pattern of the LED bars 7, the LEDs 9 of rank “1” and any one LED 9 from rank “1” to “4” are alternately arranged. On the other hand, in the combinations B1 to B4, LEDs 9 of all ranks “1” are arranged in the arrangement pattern of the LED bars 6.

  In the combinations B5 to B8, in the arrangement pattern of the LED bars 7, the LEDs 9 of rank “1” and any one LED 9 from rank “1” to “4” are alternately arranged. On the other hand, in the combinations B5 to B8, the LEDs 9 of all ranks “2” are arranged in the arrangement pattern of the LED bars 6.

  In the combinations B9 to B11, in the arrangement pattern of the LED bars 7, the LEDs 9 of the rank “1” and any one LED 9 from the ranks “2” to “4” are alternately arranged. On the other hand, in the combinations B9 to B11, the LEDs 9 of all ranks “3” are arranged in the arrangement pattern of the LED bars 6.

  In the combination B <b> 12, the LED 9 with the rank “1” and the LED 9 with the rank “3” are alternately arranged in the arrangement pattern of the LED bars 7. In the combination B13, the LED 9 of rank “1” and the LED 9 of rank “4” are alternately arranged in the arrangement pattern of the LED bars 7. On the other hand, in the combinations B12 and B13, the LEDs 9 of rank “4” are all arranged in the arrangement pattern of the LED bars 6.

  Even in the second arrangement pattern as described above, the rank average difference between the LED bars 6 and 7 is 2.0 or less.

[Effect of the embodiment]
As described above, in this embodiment, it is avoided that the LED 9 of rank “1” is mounted on any one of the LED bars 6 and 7 and the LED 9 of rank “4” is mounted on the other. LED bars 6 and 7 are produced. At this time, the LEDs 9 are mounted on the substrate 8 in accordance with the prescribed first or second arrangement pattern as described above. By incorporating the LED bars 6 and 7 thus manufactured in the backlight 3, it is possible to avoid the appearance of the chromaticity boundary due to the difference in the peak wavelengths of the LED bars 6 and 7.

<First arrangement pattern>
In the first arrangement pattern, when the LED 9 of the rank “1” or the rank “4” is used for any one of the LED bars 6 and 7, it is specified that the LED 9 is combined with the LED 9 of the rank “2” or the rank “3”. ing.

  In the combinations A1 to A8, when the LED 9 having the rank “1” or the rank “4” is used in the LED bar 7, it is defined that the LED 9 is combined with the LED 9 having the rank “2” or the rank “3”. Accordingly, when the LEDs 9 are combined in this way in any one of the LED bars 6 and 7, the average of the rank becomes 1.5 or more. Therefore, if the LED 9 of rank “2” or rank “3” is used for the other of the LED bars 6 and 7, the difference in rank average between the LED bars 6 and 7 is 1.5 or less.

  Further, in the combinations A9 to A12, when the LED 9 of the rank “1” is used in the LED bar 7, it is defined that the LED 9 is combined with the LED 9 of the rank “2” or the rank “3”. Accordingly, when the LEDs 9 are combined in this way in any one of the LED bars 6 and 7, the average of the rank becomes 1.5 or more. Therefore, when the combination of the LED 9 of rank “4” and the LED 9 of rank “2” or the combination of LED 9 of rank “4” and LED 9 of rank “3” is used for the other of the LED bars 6 and 7, The difference in rank average between the LED bars 6 and 7 is 2.0 or less.

  Further, in the combinations A13 to A18, when the LED 9 of the rank “1” and “4” is used in the LED bar 7, it is defined that the LED 9 is combined with the LED 9 of the rank “2” or the rank “3”. Accordingly, when the LEDs 9 are combined in this way in any one of the LED bars 6 and 7, the average of the rank becomes 1.5 or more. Therefore, if the LEDs 9 of rank “2” or rank “3” are used, the difference in rank average between the LED bars 6 and 7 is 1.5 or less. When the combination of the LED 9 with the rank “4” and the LED 9 with the rank “2” or the combination of the LED 9 with the rank “4” and the LED 9 with the rank “3” is used for the other of the LED bars 6 and 7, The difference in rank average between the bars 6 and 7 is 2.0 or less. Further, when the combination of the LED 9 of rank “4” and the LED 9 of rank “2” or the combination of LED 9 of rank “1” and LED 9 of rank “3” is used for the other of the LED bars 6 and 7, The difference in rank average between the bars 6 and 7 is 2.0 or less.

  About the 1st arrangement pattern, since the rank average of LED bar 6 and 7 is limited to the range of 1.5-3.5, the rank average difference between LED bar 6 and 7 becomes larger than 2.0. There is nothing. For this reason, there is a merit that it is not necessary to rank the LED bars 6 and 7 or identify the rank. However, since it is prohibited to mount the single rank LED 9 of rank “1” and rank “4” on the LED bars 6, 7, the inventory of the LED 9 of rank “1” and rank “4” is large. In this case, there is a demerit that the LED 9 in stock cannot be mounted on the LED bars 6 and 7.

  As described above, according to the first arrangement pattern, the difference in rank average between the LED bars 6 and 7 can be suppressed to 2.0 or less in any combination A1 to A18. This is because the rank average of the LEDs 9 in the LED bars 6 and 7 is in the range of 1.5 to 3.5, so that the difference in rank average between the LED bars 6 and 7 does not exceed 2.0. It is. This prevents the chromaticity boundary from being seen. Further, since there is no restriction on the combination of the LED bars 6 and 7 by the rank average, it is not necessary to distinguish the LED bars 6 and 7 to be combined in consideration of the rank average. In addition, by alternately arranging the LEDs 9 with different ranks, the average value of each rank can be set as an average while using the LEDs 9 in a well-balanced manner.

<Second arrangement pattern>
In the second arrangement pattern, the rank (single rank) of the LED 9 used for the other LED bar 6 is determined according to the rank of the LED 9 combined with the LED 9 of rank “1” in the LED bar 7.

  In the combinations B1 to B8, when any LED 9 from rank "1" to "4" is combined with the LED 9 of rank "1" in the LED bar 7, the single rank "1" in the LED bar 6 Alternatively, rank 9 LED 9 is used. In the combinations B9 to B11, in the LED bar 7, when any LED 9 from rank “2” to “4” is combined with the LED 9 of rank “1”, the LED bar 6 has a single rank “ A 3 ″ LED 9 is used. Further, in the combination B12 and B13, when the LED 9 of rank “2” or “4” is combined with the LED 9 of rank “1” in the LED bar 7, the LED 9 of the single rank “4” is combined in the LED bar 6. Is used.

  Thus, according to the second arrangement pattern, according to the rank of the LED 9 combined with the LED 9 of rank “1” in any one of the LED bars 6 and 7, the rank (single rank) mounted on the other side. Is determined. Thereby, in any combination B1 to B13, the difference in rank average between the LED bars 6 and 7 can be suppressed to 2.0 or less. This prevents the chromaticity boundary from being seen. In addition, by alternately arranging the LEDs 9 of different ranks in any one of the LED bars 6 and 7, the intermediate values of the respective ranks can be set as an average while using the LEDs 9 in a balanced manner.

  About the 2nd arrangement pattern, since the rank average of LED bar 6 and 7 is distributed in the range of 1.0-4.0, adjacent LED bar 6, so that a rank average difference may be 2.0 or less. 7 are combined. For this reason, there is a demerit that it is necessary to classify the LED bars 6 and 7 or to identify the rank. However, there is an array pattern in which single rank LEDs 9 of rank “1” and rank “4” are arranged. Thereby, unlike the first arrangement pattern, there is an advantage that the LED 9 can be mounted on the LED bars 6 and 7 even when the inventory of the LED 9 of rank “1” and rank “4” is large.

[Summary]
The method for manufacturing a backlight according to one aspect of the present invention includes an LED element (LED chip 12) that emits primary light and fluorescence that is excited by the primary light and emits secondary light having a longer wavelength than the primary light. A plurality of LEDs (LEDs 9) that emit combined light of the primary light and the secondary light by combining a body (phosphors 16 and 17) are linearly mounted on a substrate at linear intervals. Difference between the production process for producing the light source (LED bar 6, 7) and the adjacent linear light source of the average peak wavelength which is the average of the peak wavelengths of the primary light emitted by the LEDs in the linear light source The combination step of combining a plurality of the linear light sources so that the peak wavelength difference is equal to or less than a specified value, and the combined linear light sources are joined in a straight line and incorporated into the light guide plate (light guide plate 5). Embedder It includes the door.

  Moreover, the backlight (backlight 3) which concerns on 1 aspect of this invention is excited by the said primary light and the LED element (LED chip | tip 12) which emits primary light, and the secondary whose wavelength is longer than the said primary light. A plurality of LEDs (LEDs 9) that emit combined light of the primary light and the secondary light by being combined with phosphors that emit light (phosphors 16, 17) are linearly arranged at intervals. A plurality of linear light sources (LED bars 6 and 7) joined so as to be aligned with each other, and light emitted from the linear light source incident at least from one end side is planarized on the liquid crystal panel (liquid crystal panel 4). A linear light source plate (light guide plate 5), and a plurality of the linear light sources adjacent to each other with an average peak wavelength that is an average of the peak wavelengths of the primary light emitted by the LEDs in the linear light source. Is the difference between the light sources Over peak wavelength difference are combined so becomes below the specified value.

  In the above configuration, the plurality of linear light sources are combined in the combining step so that the peak wavelength difference is equal to or less than the specified value. Therefore, by appropriately setting the specified value, when light is emitted from the backlight to the liquid crystal panel, the boundary of chromaticity due to the difference in peak wavelength of the light emitted from the two adjacent linear light sources is prevented from being seen. can do.

  In the production process, the backlight manufacturing method uses the LEDs selected without distinguishing the peak wavelength of the primary light emitted from each LED in order to produce the linear light source, and the combination process includes: An average calculation step of calculating the average peak wavelength of each linear light source, and a rank classification step of classifying the linear light source into ranks defined in a plurality of different peak wavelength ranges based on the calculated average peak wavelength And a combination determining step of determining a combination of the linear light sources in which the peak wavelength difference is equal to or less than the specified value based on the rank.

  In said structure, a linear light source is produced using LED which sorted without distinguishing the peak wavelength. Further, linear light sources are classified into ranks based on the calculated average peak wavelength, and further, combinations of linear light sources whose peak wavelength difference is equal to or less than a predetermined value are determined based on the ranks. Thereby, it is not necessary to distinguish LEDs according to the peak wavelength in advance, and management for that purpose is not necessary. Instead of this, it is necessary to manage the linear light source according to the rank, but the management target is greatly reduced. Therefore, management of parts can be simplified.

  In the manufacturing method of the backlight, in the average calculation step, it is preferable that the LED that is a target for calculating the average peak wavelength is limited to a predetermined range from an end portion where the adjacent linear light sources are joined. .

  In the above configuration, as described above, it is necessary for the chromaticity boundary not to occur that the average peak wavelength in the vicinity of the junction is close to the linear light source, rather than the entire average peak wavelength of the linear light source. Therefore, the target for calculating the average peak wavelength is limited to the LEDs in the above range. As a result, the number of LEDs that measure the peak wavelength in the linear light source is greatly reduced relative to the total number of LEDs in the linear light source. Therefore, since the measurement time of the peak wavelength of each LED in the linear light source is significantly shortened, the time required for manufacturing the backlight can be shortened.

  Prior to the combination step, the backlight manufacturing method further includes an LED rank classification step for classifying the LEDs into ranks defined in advance in a plurality of different peak wavelength ranges, and the combination step includes the first step. Prior to the manufacturing process, for the two adjacent linear light sources, an array of the LEDs having a single and different rank, each having a peak wavelength difference larger than the specified value, is arranged in the two adjacent lines. It is preferable to include an array determining step of determining one of the linear light sources and determining the array of the LEDs in the linear light source.

  In the above configuration, for one of the two adjacent linear light sources, for the two adjacent linear light sources, the peak wavelength difference is single and different from each other such that the peak wavelength difference is larger than the specified value. The LED array is excluded. As an arrangement | sequence excluded, it is the arrangement | sequence by LED of the single rank of only rank "1" shown in the above-mentioned Table 1, or rank "4", for example. By excluding such an arrangement, LEDs of other ranks are arranged for the one linear light source. Thereby, even if LEDs of any rank are arranged in the other linear light source, the peak wavelength difference between the two linear light sources can be suppressed to a specified value or less.

  Prior to the combination step, the backlight manufacturing method further includes an LED rank classification step for classifying the LEDs into ranks defined in advance in a plurality of different peak wavelength ranges, and the combination step includes the manufacturing step. Prior to the process, among the two linear light sources adjacent to each other, the ranks in the range in which the peak wavelength is short among the single and different ranks of the LEDs so that the peak wavelength difference is larger than the specified value. The LED and any one of the LEDs in all ranks are combined to determine the arrangement of the LEDs for one of the two adjacent linear light sources, and according to the combination of the LEDs It is preferable that the arrangement | sequence determination process which determines the arrangement | sequence of the said LED about the other said linear light source is included.

  In the above configuration, for one of the two adjacent linear light sources, the peak wavelength difference is larger than the specified value, and each of the single and different rank LEDs has a peak wavelength in a short range of ranks. An LED and an LED having a different rank from the LED are combined. For example, the rank LED having a short peak wavelength range is the LED of rank “1” shown in Table 1 described above, and any one of ranks “2” to “4” can be combined with this LED. LED. Thereby, if the arrangement | sequence of LED in one linear light source is determined previously, the arrangement | sequence of LED in the other linear light source can be determined according to it. Therefore, LEDs can be used in a balanced manner.

  In the method for manufacturing the backlight and the backlight, the primary light is preferably blue light. This is because the peak of blue light is the largest in the LED light, and it is desirable to set the specified value so that the boundary of chromaticity due to the peak is not conspicuous.

  In the manufacturing method of the backlight and the backlight, the specified value is preferably 7.5 nm. This is because the specified value is 7.5 nm for blue light.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. Is also included in the technical scope of the present invention. Furthermore, a new technical feature can be formed by combining the technical means disclosed in each embodiment.

  The backlight manufacturing method according to the present invention can be suitably used for manufacturing a backlight that uses a combination of a plurality of linear light sources (LED bars) on which a plurality of LEDs are mounted.

DESCRIPTION OF SYMBOLS 1 Liquid crystal display device 2 Liquid crystal panel 3 Backlight 5 Light guide plate 6 LED bar (linear light source)
8 Substrate 7 LED bar (Linear light source)
9 LED
12 LED chip (LED element)
16 phosphor 17 phosphor 21 LED bar combination device 22 memory 23 storage unit 24 display unit 25 arithmetic processing unit 26 average calculation unit 27 wavelength rank classification unit 28 combination determination unit 31 LED characteristic measurement device

Claims (10)

A combined light of the primary light and the secondary light by combining an LED element that emits primary light and a phosphor that is excited by the primary light and emits secondary light having a longer wavelength than the primary light. A step of producing a linear light source by mounting a plurality of LEDs emitting light on a substrate at linear intervals, and
A plurality of peak wavelength differences, which are differences between adjacent linear light sources that are an average peak wavelength that is an average of peak wavelengths of the primary light emitted by the LEDs in the linear light source, are equal to or less than a predetermined value. A combination step of combining the linear light sources;
And a step of assembling the combined linear light sources so as to be aligned in a straight line and incorporating the linear light sources into a light guide plate. In the production process, in order to produce the linear light source, the LEDs selected without distinction of the peak wavelength of the primary light emitted from each LED are used.
The combination process includes
An average calculation step of calculating the average peak wavelength of each linear light source;
A rank classification step of classifying the linear light source into ranks defined in a plurality of different peak wavelength ranges based on the calculated average peak wavelength;
The method for manufacturing a backlight according to claim 1, further comprising: a combination determining step of determining a combination of the linear light sources in which the peak wavelength difference is equal to or less than the specified value based on the rank. .   The said average calculation process WHEREIN: The said LED used as the object which calculates the said average peak wavelength is limited to a predetermined range from the edge part to which the said adjacent linear light source is joined. Manufacturing method of backlight. Prior to the combining step, the method further includes an LED rank classification step of classifying the LEDs into ranks defined in advance in a plurality of different peak wavelength ranges,
In the combination step, prior to the first manufacturing step, for the two linear light sources adjacent to each other, the single and different ranks of the LEDs are arranged such that the peak wavelength difference is larger than the specified value. 2. The backlight according to claim 1, further comprising an array determining step of determining one of the two adjacent linear light sources and determining the array of the LEDs in the linear light source. Manufacturing method. Prior to the combining step, the method further includes an LED rank classification step of classifying the LEDs into ranks defined in advance in a plurality of different peak wavelength ranges,
In the combination step, prior to the manufacturing step, for the two linear light sources adjacent to each other, among the LEDs of single and different ranks such that the peak wavelength difference is larger than the specified value, Combining the LEDs having a rank in a short peak wavelength range and any one of the LEDs in all ranks, and determining the arrangement of the LEDs for one of the two adjacent linear light sources, The method for manufacturing a backlight according to claim 1, further comprising an array determining step of determining an array of the LEDs for the other linear light source in accordance with the combination of the LEDs.   The method for manufacturing a backlight according to any one of claims 1 to 5, wherein the primary light is blue light.   The method for manufacturing a backlight according to claim 6, wherein the specified value is 7.5 nm. A combined light of the primary light and the secondary light by combining an LED element that emits primary light and a phosphor that is excited by the primary light and emits secondary light having a longer wavelength than the primary light. A plurality of linear light sources arranged in a straight line at intervals, and a plurality of linear light sources joined to be aligned with each other;
A light guide plate that emits light emitted from the linear light source incident from at least one end side into the liquid crystal panel in a plane,
A plurality of the linear light sources define a peak wavelength difference that is a difference between adjacent linear light sources having an average peak wavelength that is an average of peak wavelengths of the primary light emitted by the LEDs in the linear light source. Backlight characterized by being combined so as to be below the value.   The backlight according to claim 8, wherein the primary light is blue light.   The backlight according to claim 9, wherein the specified value is 7.5 nm.

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