JP6695114B2 - Light emitting device - Google Patents

Description

  The present invention relates to a light emitting device.

  There is known a COB (Chip On Board) light emitting device in which a light emitting element such as an LED (light emitting diode) element is mounted on a general-purpose substrate such as a ceramic substrate or a metal substrate. In such a light-emitting device, a resin containing a phosphor is used to seal an LED element that emits blue light, for example, and the light from the LED element is excited to mix the light obtained by exciting the phosphor, so that the light is emitted depending on the application. You are getting white light.

  For example, in Patent Document 1, a highly heat conductive heat dissipation base having a mounting surface for die bonding, a hole portion mounted on the heat dissipation base and exposing a part of the mounting surface, and the outside of the heat dissipation base. A circuit board having a projecting portion projecting outward from the peripheral edge, a light emitting element mounted on the mounting surface through the hole, and a translucent resin body sealing the upper side of the light emitting element are provided. There is described a light emitting diode in which a through hole that is electrically connected to a light emitting element is formed at an outer peripheral edge of a projecting portion, and an external connection electrode is provided on an upper surface and a lower surface of the through hole.

  Further, in Patent Document 2, a cavity in which a concave portion is formed, a convex heat slug (pedestal portion) attached to the cavity in a state of penetrating a bottom portion of the concave portion, and a submount substrate mounted on the heat slug are disclosed. And a plurality of LED chips arranged on the submount substrate, a lead frame electrically connected to each LED chip, a phosphor layer containing each LED chip, and a silicone resin encapsulated in the recess. An LED package having a closed lens is described.

  Further, there is known an illumination device in which a plurality of LEDs are integrated and arranged to increase the light amount. For example, Patent Document 3 discloses a lens array in which a plurality of LEDs 3, a substrate 4 on which the LEDs 3 are mounted, and a plurality of lens elements for condensing or diverging irradiation light emitted from the LEDs are integrally formed. An LED lighting device having 2 and 2 is described.

JP, 2006-005290, A JP, 2010-170945, A JP 2012-042670 A

  In order to increase the amount of emitted light, consider manufacturing a light emitting device in which a plurality of light emitting units are formed on one common substrate and each light emitting unit includes a plurality of LED elements. In such a light emitting device, there is a case where a driver designed for driving a light emitting device using a certain LED element is desired to be used in a light emitting device using another LED element, for example, in order to reduce the manufacturing cost. However, if LED elements having different forward voltages are used, the forward voltage of the entire device may change significantly compared to the original light emitting device, and thus it may not be possible to drive with a common driver.

  Therefore, an object of the present invention is to provide a light emitting device in which a plurality of light emitting portions each including a plurality of LED elements are formed on a common substrate by using a common driver regardless of the forward voltage of each LED element. It is to be drivable.

  A substrate, a plurality of light emitting units arranged on the substrate, and a driver for driving the plurality of light emitting units are provided. Each of the plurality of light emitting units is divided into a plurality of columns connected in parallel to each other. Each of the columns has a plurality of LED elements connected in series with each other, and the total of the forward voltages of the LED elements connected in series in the plurality of light emitting units is set within the range of the voltage that can be driven by the driver. A light emitting device is provided, wherein the number of LED elements connected in series is set in each of the plurality of light emitting units.

In the above light emitting device, it is preferable that the plurality of light emitting units are connected in series to the driver.
In the above light emitting device, it is preferable that the plurality of light emitting units are divided into a plurality of groups connected in parallel to the driver, and the light emitting units included in each of the plurality of groups are connected to each other in series.
In the above light emitting device, it is preferable that the plurality of light emitting units have LED elements having a higher forward voltage as the plurality of LED elements, as the number of LED elements connected in series is smaller.

  According to the present invention, a light emitting device in which a plurality of light emitting portions each including a plurality of LED elements are formed on a common substrate is driven by a common driver regardless of the forward voltage of each LED element. It will be possible.

It is a front view and a rear view of the illuminating device 1. 3A and 3B are a top view and a side view of the light emitting device 2. It is a top view of the lens array 40. FIG. 6 is a top view and a vertical cross-sectional view of the light emitting section 20. 3 is an overall circuit diagram of the light emitting device 2. FIG. It is a top view of the light emitting portion 20 _3. It is a figure which shows the arrangement | positioning of the LED element 30 in the light-emitting device 2 typically. 6 is a flowchart showing an example of a manufacturing process of the light emitting device 2. FIG. 6 is a diagram showing an example of a method of fixing the lens array 40 to the substrate 10. It is a figure which shows the example of the positioning method of the board | substrate 10 and the lens array 40. FIG. It is a top view and a side view of 2 A of light-emitting devices. It is a top view of 20 A of light-emitting parts. It is a figure which shows typically arrangement | positioning of the LED element 30 in the light-emitting device 2B. FIG. 3 is a top view of a light emitting device 2C and a light emitting section 20C in the light emitting device 2C. It is a figure which shows typically arrangement | positioning of the LED element 30 in the light-emitting device 2D. It is a figure which shows the arrangement | positioning of the LED element 30 in the light-emitting device 2E typically. It is a top view and a side view of light-emitting device 2F. It is a top view and a longitudinal cross-sectional view of a light emitting unit 20G.

  Hereinafter, a light emitting device and a method for manufacturing the same will be described with reference to the drawings. However, it should be understood that the invention is not limited to the drawings or the embodiments described below.

  1A and 1B are a front view and a rear view of the lighting device 1. The lighting device 1 is, for example, a device that can be used as a floodlight for illumination, and has, as an example, a total of six light emitting devices 2 arranged in two rows and three columns as shown in FIG. The lighting device 1 is configured as one device by arranging the cases (housings) 3 of the respective light emitting devices 2 close to each other. There are various examples of the number of light emitting devices 2 included in one lighting device, such as two, four, or eight or more, in addition to the illustrated one. As shown in FIG. 1B, the illuminating device 1 has a radiation fin (heat sink) 4 on the back surface of the case 3 of each light emitting device 2 for promoting the release of heat generated in the light emitting device 2.

  FIG. 2A and FIG. 2B are a top view and a side view of the light emitting device 2. As shown in FIGS. 2A and 2B, the light emitting device 2 includes a substrate 10, a plurality of light emitting units 20 formed on the substrate 10, and a plurality of light emitting units 20 arranged on the plurality of light emitting units 20. And a lens array 40. Further, as shown in FIGS. 1B and 2B, each light emitting device 2 has a radiation fin 4 on the back surface of the substrate 10 for radiating the heat generated by the plurality of light emitting units 20.

  The substrate 10 is a substantially rectangular substrate having a circular opening 13 in its center. For example, the vertical and horizontal lengths of the substrate 10 are each about 10 cm, and the thickness of the substrate 10 is about 1 to 2 mm. The board 10 is configured by bonding the circuit board 12 onto the metal board 11 with an adhesive sheet, for example. The end portion of the substrate 10 is fixed to the case 3 of the light emitting device 2 shown in FIG.

  The metal substrate 11 functions as a mounting substrate for mounting the light emitting unit 20 and a heat radiating substrate for radiating the heat generated in the light emitting unit 20, and thus is made of, for example, aluminum having excellent heat resistance and heat radiation. However, the material of the metal substrate 11 may be another metal such as copper as long as it has excellent heat resistance and heat dissipation.

  The circuit board 12 is an insulating board such as a glass epoxy board, a BT resin board, a ceramics board, or a metal core board. A wiring pattern 14 for electrically connecting the plurality of light emitting units 20 to each other is formed on the upper surface of the circuit board 12. Two connection electrodes 15 for connecting the light emitting device 2 to an external power source are formed on the right end of the circuit board 12 shown in FIG. One of the connection electrodes 15 is a + electrode, and the other is a − electrode. When these are connected to an external power source and a voltage is applied, the plurality of light emitting units 20 of the light emitting device 2 emit light.

  The light emitting units 20 are a plurality of independent light emitting units formed on the substrate 10, which is one common substrate, and are evenly arranged on the substrate 10 so as to surround the opening 13. In the illustrated example, the light emitting device 2 has 22 light emitting units 20. As will be described later, each light emitting unit 20 has a plurality of LED elements (an example of a light emitting element). In order to make the light emitted from the light emitting device 2 uniform, it is preferable that the interval (pitch) between the light emitting units 20 is constant. However, the pitch of the light emitting units 20 may be different between the vertical direction and the horizontal direction of the substrate 10.

  FIG. 3 is a top view of the lens array 40. The lens array 40 is an assembly of lenses in which a plurality of lenses 41 are integrally formed. In the illustrated example, the lens array 40 has 22 lenses 41 arranged close to each other except for the center thereof. The central portion 42 of the lens array 40 is preferably an opening. As shown in FIG. 2B, the optical axis X of each lens 41 coincides with the normal direction of the substrate 10. The lenses 41 are provided in the same arrangement as the light emitting units 20 on the substrate 10 so as to correspond to the respective light emitting units 20, and collect the light emitted from the corresponding light emitting units 20. Each lens 41 has, for example, the same shape and size. The end portion of the lens array 40 is fixed to the case 3 of the light emitting device 2 shown in FIG. In particular, for use as a light projector, it is required to configure the light emitting device 2 as small as possible so that the resistance received by the wind during use becomes small. For this reason, it is preferable that the adjacent lenses 41 are brought into contact with each other without leaving a space therebetween to increase the density of the lens 41 portion with respect to the entire lens array 40. Since the light emitting units 20 and the lenses 41 have a one-to-one correspondence, the pitch of the light emitting units 20 is determined by the diameter of the lens 41.

  As described above, the substrate 10 has the opening 13 in the center. The opening 13 is formed at the same position on the metal board 11 and the circuit board 12. Further, it is preferable that the lens 41 is not arranged above the opening 13 and the lens array 40 is opened above the opening 13. The shape of the opening 13 is not limited to a circular shape, but may be another shape such as a rectangle, and the position of the opening 13 may not be strictly in the center of the substrate 10. In the light emitting device 2, the opening 13 in the substrate 10 is advantageous in terms of heat dissipation, as described below.

  First, in the light emitting device 2, since the metal substrate 11 is exposed at the edge of the opening 13, the area of the metal substrate 11 in contact with the outside air increases. As a result, a part of the heat transferred from the light emitting section 20 (light emitting element) to the metal substrate 11 is radiated to the outside of the device also from the edge of the opening 13. Further, in the light emitting device 2, the heat radiation fins 4 on the back side of the substrate 10 come into contact with the outside air through the opening 13 even on the front side of the substrate 10, so that the area where the heat radiation fins 4 come into contact with the outside air also increases. As a result, part of the heat transferred from the metal substrate 11 to the heat radiation fins 4 is also radiated to the front side of the substrate 10 through the openings 13. Therefore, in the light emitting device 2, it is possible to promote the release of the heat generated in each light emitting unit 20 (light emitting element) to the outside of the device by the opening 13.

  From the viewpoint of heat dissipation, the diameter of the opening 13 needs to have a certain size. For example, the diameter d1 of the opening 13 is preferably at least larger than the diameter d2 of each light emitting unit 20, and more preferably larger than the arrangement interval (pitch) d3 of the plurality of light emitting units 20. In the illustrated example, the pitch d3 of the light emitting units 20 is larger than the diameter d2 of the light emitting units 20.

  Further, as shown in FIG. 2A, an inspection terminal 16 for confirming the operation (lighting) of the light emitting unit 20 is provided on the upper surface of the circuit board 12 for each light emitting unit 20. The inspection terminals 16 are arranged so that each pair of two terminals sandwiches the corresponding light emitting unit 20. The inspection terminals 16 are arranged outside the light emitting section 20, but since the wiring pattern 14 for simultaneously lighting the plurality of light emitting sections 20 is also provided on the circuit board 12, the arrangement position of the inspection terminals 16 emits light. If it is too far from the portion 20, it becomes difficult to route the wiring. Therefore, as shown in FIG. 2A, the inspection terminals 16 of each set are formed on the circuit board 12 at a position within the diameter of the main surface of the lens 41 corresponding to the target light emitting section 20. ..

  Further, in order to prevent erroneous measurement, the two terminals forming each set of the inspection terminals 16 are evenly arranged with a common space d between the plurality of light emitting units 20. Furthermore, if possible in relation to the wiring pattern 14, it is preferable to arrange the two terminals forming the inspection terminals 16 of each set so as to be arranged at a common angle with respect to the sides of the substrate 10. As described above, if the arrangement of the inspection terminals 16 of a plurality of sets is aligned, the operation of each light emitting unit 20 can be easily confirmed when the operation of the light emitting unit 20 is sequentially confirmed, and the frequency of erroneous measurement can be reduced. It can be lowered.

  FIG. 4A to FIG. 4C are a top view and a vertical sectional view of the light emitting unit 20. More specifically, FIG. 4A is a top view of the light emitting unit 20, FIG. 4B is a cross-sectional view taken along line IVB-IVB of FIG. 4A, and FIG. It is sectional drawing which followed the IVC-IVC line of FIG. The light emitting unit 20 has a plurality of LED elements 30, a sealing frame 23, and a sealing resin 24 as main components.

  The LED element 30 is an example of a light emitting element, and is, for example, a blue LED that emits blue light having an emission wavelength band of about 450 to 460 nm. In each light emitting section 20, the circuit board 12 has an opening 21, and the metal substrate 11 is exposed through the opening 21. The LED element 30 is mounted on the metal substrate 11 exposed through the opening 21. By mounting the LED element 30 directly on the metal substrate 11 in this manner, heat dissipation of heat generated by the LED element 30 and particles of the phosphor described later is promoted.

  In addition, the LED elements 30 are arranged and mounted in a grid in, for example, a rectangular mounting area 22 in the opening 21. FIG. 4A shows an example in which 16 LED elements 30 in 4 rows and 4 columns are mounted. In this case, four LED elements 30 are connected in series, and four sets thereof are further connected in parallel. In this way, the LED elements 30 are connected in series in parallel in each of the light emitting units 20 in the number of series and the number of parallels set for the light emitting units 20.

In the following, particularly when the number of LED elements 30 in series is four, the term “light emitting section 20 ₄ ” is used. When the light emitting units are not distinguished by the number of LED elements 30 in series, they are simply referred to as “light emitting units 20”.

  The lower surface of the LED element 30 is fixed to the upper surface of the metal substrate 11 with, for example, a transparent insulating adhesive or the like. The LED element 30 has a pair of element electrodes on the upper surface, and the element electrodes of the adjacent LED elements 30 are electrically connected to each other by a wire 31, as shown in FIG. The wire 31 extending from the LED element 30 located on the outer peripheral side of the opening 21 is finally connected to the wiring pattern 14 of the circuit board 12. As a result, a current is supplied to each LED element 30 via the wire 31.

  The sealing frame 23 is a substantially rectangular resin frame made of, for example, a white resin in accordance with the size of the opening 21 of the circuit board 12, and the circuit board is configured to surround the LED element 30 in the light emitting section 20. It is fixed to the outer peripheral portion of the opening 21 on the upper surface of 12. The sealing frame 23 is a dam material for preventing the sealing resin 24 from flowing out. Further, the sealing frame 23 has, for example, a reflective coating on the surface thereof, so that the light emitted laterally from the LED element 30 is directed to the upper side of the light emitting section 20 (metal viewed from the LED element 30). The light is reflected toward the side opposite to the substrate 11). Note that, in FIG. 4A, the sealing frame 23 is illustrated as being transparent.

  The sealing resin 24 is filled in a region surrounded by the sealing frame 23 on the metal substrate 11 to integrally cover and protect (seal) the entire LED element 30 and the wire 31 of the light emitting unit 20. As the sealing resin 24, for example, a colorless and transparent resin such as an epoxy resin or a silicone resin, particularly a resin having a heat resistance of about 250 ° C. may be used.

  In addition, a fluorescent material (not shown) such as a yellow fluorescent material is dispersed and mixed in the sealing resin 24. The yellow phosphor is a particulate phosphor material such as YAG (yttrium aluminum garnet) that absorbs blue light emitted from the LED element 30 and converts the wavelength into yellow light. The light emitting unit 20 emits white light obtained by mixing blue light from the LED element 30 which is a blue LED and yellow light obtained by exciting the yellow phosphor with the blue light.

Alternatively, the sealing resin 24 may contain a plurality of types of phosphors such as a green phosphor and a red phosphor. The green phosphor is a particulate phosphor material such as (BaSr) ₂ SiO ₄ : Eu ²⁺ that absorbs blue light emitted from the LED element 30 and converts the wavelength into green light. The red phosphor is a particulate phosphor material such as CaAlSiN ₃ : Eu ²⁺ that absorbs blue light emitted from the LED element 30 and converts the wavelength into red light. In this case, the light emitting unit 20 is a white light obtained by mixing blue light from the LED element 30 which is a blue LED with green light and red light obtained by exciting the green phosphor and the red phosphor thereby. Emits light.

FIG. 5A and FIG. 5B are circuit diagrams of the entire light emitting device 2. Reference numeral 50 refers to a driver for driving the 22 light emitting units 20 of the light emitting device 2, reference numeral 20 _3, serial number of the LED elements 30 refers to three light-emitting portion. In the light emitting device 2, as shown in FIG. 2A, a total of five switching terminals 17 are provided on the upper surface of the circuit board 12. Depending on the relationship between the number of light emitting devices 2 included in the lighting device 1 and the maximum voltage that can be supplied by the driver 50 to be used, the connection manner of the switching terminals 17 is changed to connect the light emitting units 20 in series and parallel. It is possible to switch. For example, depending on how the switching terminals 17 are connected to each other, 22 light emitting units 20 are connected in series to the driver 50 as shown in FIG. 5 (A), or as shown in FIG. 5 (B). The 22 light emitting units 20 are divided into two sets connected in parallel to the driver 50, and 11 light emitting units 20 included in each set are connected in series with each other.

  As described above, each light emitting unit 20 has a plurality of LED elements 30 which are divided into a plurality of columns connected in parallel with each other and are connected in series with each other in each of the plurality of columns. In the light emitting device 2, the light emitting devices 20 are connected in series so that the total forward voltage (Vf) of the LED elements 30 connected in series in the entire device falls within the range of the voltage that can be driven by the driver 50. The number of LED elements 30 to be set is set. Therefore, in the light emitting device 2, all the light emitting units 20 do not necessarily have the same number of LED elements 30, and in general, the number of LED elements 30 included in one light emitting unit 20 differs for each light emitting unit 20.

  For example, assume that the maximum voltage that the driver 50 can supply is 264V. Further, it is assumed that when the LED element (1) as the LED element 30 is used, the Vf of one light emitting unit 20 having four in series is 10.5 to 11.7V. In this case, even if 22 light emitting units 20 are connected in series, Vf of the entire light emitting device 2 is 231.0 to 257.4 V, which is within the range that can be driven by the driver 50. On the other hand, when another LED element (2) is used as the LED element 30, it is assumed that the Vf of one light emitting section 20 having four in series becomes 11.6 to 13.6V. In this case, when 22 light emitting units 20 are connected in series, Vf of the entire light emitting device 2 becomes 255.0 to 299.4 V, which exceeds the maximum voltage that can be driven by the driver 50.

Therefore, when the latter LED element (2) is used, the number of series in some of the light emitting units 20 is set to 3, and the number of series in which Vf is 11.6 to 13.6 V is 4. a light emitting portion 20 _4, Vf combines a number of series and three light-emitting portion 20 ₃ is 8.69～10.21V. Then, out of a total of 22 light emitting units 20, if at least 11 in the light emitting portion 20 _3, Vf across the light emitting device 2 becomes less 264V, it falls within the scope that can be driven by a driver 50. Therefore, the light emitting device 2, when using the LED elements (1), the 22 light emitting units 20 is the series number of the four light-emitting portion 20 _4, when using the LED elements (2) Among the 22 light emitting units 20, for example, 11 are the light emitting units 20 ₄ having a series number of ₄ and the remaining 11 are the light emitting units 20 ₃ having a series number of 3.

  As described above, in the light emitting device 2, the number of LED elements 30 connected in series in each of the light emitting units 20 is different, that is, one light emitting unit 20 has m units and another light emitting unit 20 has n units. As a result, the total sum of the forward voltages of the LED elements 30 connected in series in the entire device is adjusted so as to be within the range of the voltage that can be driven by the target driver 50. Therefore, even if the type of LED element 30 used is changed, the light emitting device 2 can be driven by the common driver 50 regardless of the forward voltage of each LED element 30.

Figure 6 is a top view of the light emitting portion 20 _3. Figure 4 (A) light emitting section 20 _third light emitting portion 20 (the light emitting portion 20 ₄₎ shown in FIG 6 shown in differs only the number of the LED elements 30, but otherwise have the same configuration. The light emitting section 20 ₄ has 16 LED elements 30, which are connected in series four by four, and the four sets are further connected in parallel, while the light emitting section 20 ₃ has 12 LED elements. 30 and they are connected in series three by three, four sets of which are further connected in parallel. In both of the light emitting units 20 ₄ and 20 ₃ , the mounting area 22 is a rectangular area having the same shape and size, and the LED element 30 is always mounted at least at the four corners of the mounting area 22. Then, the LED elements 30 are evenly mounted inside the mounting region 22 of both of the light emitting units 20 ₄ and 20 ₃ . In the light emitting units 20 ₄ and 20 ₃ , the mounting densities of the LED elements 30 are different from each other because the mounting areas 22 have the same size and the element pitch is different. Further, in the light emitting units 20 ₄ and 20 ₃ , the light emitting densities when the light emitting units are regarded as one light emitting body are different from each other.

FIG. 7 is a diagram schematically showing the arrangement of the LED elements 30 in the light emitting device 2. In FIG. 2A and FIG. 2B, the plurality of light emitting units are simply referred to as “light emitting unit 20”, but in the light emitting device 2, the forward voltage of the entire device is adjusted as described above. Therefore, for example, the light emitting unit 20 ₄ having the _four serial numbers and the light emitting unit 20 ₃ having the three serial numbers are combined. FIG. 7 shows an example in which the light emitting units 20 ₄ and the light emitting units 20 ₃ are alternately connected. However, depending on the driver 50 used, all the light emitting units 20 may have the same number of LED elements 30 in series, or may have two or less or five or more light emitting units 20 in series.

  As described above, the LED element 30 of each light emitting unit 20 is mounted in the mounting region 22 having a shape and size common to the plurality of light emitting units 20 according to the number of series and the number of parallels set for the light emitting unit 20. Implemented in density. As a result, the light emitting diameters of the plurality of light emitting units 20 become the same, so that a lens array including a plurality of lenses 41 having the same shape and size regardless of the number of LED elements 30 included in each light emitting unit 20. It becomes possible to use 40.

  In addition, since the emitted light amount decreases in the light emitting unit 20 in which the number of the LED elements 30 is relatively reduced, when the light emitting units 20 having different numbers of series and / or parallel numbers are combined, the light emitting device 2 as a whole has uneven emission light amount. Can occur. Therefore, an LED element having a higher forward voltage may be used as the LED element 30 as the number of series and parallel numbers of the LED elements 30 is smaller. Since the emitted light becomes brighter if the LED element has a high forward voltage, by selecting the LED element to be used for each light emitting section 20, the emitted light amount is made uniform among the plurality of light emitting sections 20, and unevenness of the unevenness is obtained. It is possible to emit light that does not exist.

  However, since the lighting device 1 is installed far away from human eyes due to the nature of being used as a light projector, uneven brightness on the light emitting device 2 does not pose a problem. Therefore, the light emitting units 20 having different numbers of series and / or parallels do not necessarily have to be evenly arranged in the light emitting device 2. Alternatively, LED elements having the same forward voltage may be used in all the light emitting units 20.

  FIG. 8 is a flowchart showing an example of the manufacturing process of the light emitting device 2. When manufacturing the light emitting device 2, first, a plurality of light emitting units 20 are collectively formed on the substrate 10, and a plurality of sets of LED elements 30 are mounted on each light emitting unit 20. At that time, for each light emitting unit 20, the plurality of LED elements 30 are mounted on the metal substrate 11 in the opening 21 of the circuit board 12 (S1). Next, the LED elements 30 are connected to each other in series and parallel by the wires 31 (S2). Further, the sealing frame 23 is fixed to the outer peripheral portion of the opening 21 (S3). Further, the sealing resin 24 containing the phosphor is filled in the region surrounded by the sealing frame 23 on the metal substrate 11 to seal the plurality of LED elements 30 (S4).

  As shown in FIG. 2A, two positioning holes 18a and 18b are formed on the diagonal line of the upper surface of the circuit board 12 as an example, and the circuit board 12 corresponding to each light emitting unit 20 is formed. The position of the opening 21 is determined with reference to the positions of the positioning holes 18a and 18b. That is, the mounting position of the LED element 30 and the disposing position of the sealing frame 23 of each light emitting unit 20 are determined based on the positions of the positioning holes 18a and 18b. This reduces variations in the formation position of the light emitting unit 20.

  Subsequently, the lens array 40 including the plurality of lenses 41 is arranged on the light emitting unit 20 with the relative positions of the respective light emitting units 20 and the corresponding lenses 41 being roughly aligned (S5). At this time, the lens array 40 is fixed to the substrate 10 by holding the substrate 10 and the ends of the lens array 40 by the case 3, for example. Alternatively, the lens array 40 may be fixed to the substrate 10 by the method described below.

  9A to 9C are diagrams showing an example of a method of fixing the lens array 40 to the substrate 10. 9A to 9C show a top view of the substrate 10, a top view of the lens array 40, and a vertical cross-sectional view of the light emitting device 2 along the diagonal line L, respectively. In FIGS. 9A to 9C, the numbers of the light emitting units 20 and the lenses 41 are shown as eight for simplicity.

  In the illustrated example, the substrate 10 and the lens array 40 are positioned using the positioning holes 18a and 18b. In this case, on the diagonal line L of the lower surface of the lens array 40 (the surface facing the substrate 10), two support portions 43a and 43b are provided in advance in accordance with the positions of the positioning holes 18a and 18b. The support portions 43 a and 43 b are columnar members integrally formed with the lens array 40 or bonded to the lens array 40. The substrate 10 and the lens array 40 are positioned by fitting the support portions 43a and 43b into the positioning holes 18a and 18b, respectively. Accordingly, the optical axis of each lens 41 can be easily aligned with the center of each light emitting unit 20, so that the process of adjusting the relative positions of the plurality of light emitting units 20 and the plurality of lenses 41 is simplified.

  The positioning holes 18a and 18b have a larger diameter along the diagonal line L as the distance from the one end P of the diagonal line L increases. For example, as shown in FIGS. 2A and 9A, the positioning holes 18a and 18b are both circular, and the positioning hole 18b farther from the one end P than the positioning hole 18a has a diameter. large. Alternatively, the positioning holes 18a and 18b may be elliptical (long holes) whose major axis is in the direction of the diagonal line L. In this case, the positioning hole 18b has a larger major axis than the positioning hole 18a. Further, the diameters of the portions of the lower ends of the support portions 43a and 43b that fit into the positioning holes 18a and 18b are slightly smaller than the diameters of the positioning holes 18a and 18b. As a result, the relative positions of the plurality of light emitting units 20 and the plurality of lenses 41 along the diagonal line L can be changed, so that the relative positions can be changed even when the substrate 10 and the lens array 40 thermally expand or contract at different rates. Fine adjustment is possible.

  Thus, the relative positions of the plurality of light emitting units 20 and the plurality of lenses 41 can be changed according to the thermal expansion when the light emitting device 2 is turned on and the thermal contraction when the light emitting device 2 is turned off. The lens array 40 is fixed to each other. Then, the substrate 10 and the lens array 40 are accurately positioned by the method described below (S6).

  The positioning of the substrate 10 and the lens array 40 in S6 is performed according to the following concept. Due to the heat generated when the light emitting device 2 is turned on, the metal substrate 11 made of aluminum and the circuit board 12 made of resin and the lens array 40 made of glass, which form the substrate 10, expand at different thermal expansion rates. For example, assuming that the temperature of the substrate 10 and the lens array 40 rises by about 100 ° C. by lighting, in the case of the substrate 10 having one side of about 10 cm, the expansion amount of about 1 mm between the substrate 10 and the lens array 40. Differences can occur. Therefore, the relative position of each light emitting unit 20 and each lens 41 is previously shifted by Δd in the opposite direction in consideration of the difference Δd in the amount of expansion. As a result, when the light emitting device 2 is driven (a plurality of light emitting units 20 are turned on) and thermal expansion occurs, the difference between the preset displacement amount and the expansion amount due to thermal expansion cancels each other out, and each light emitting unit 20 is canceled. And the optical axes of the lenses 41 coincide with each other. Therefore, when the light emitting device 2 is driven and thermal expansion occurs in the substrate 10 and the lens array 40, it is possible to improve the emission efficiency from each light emitting unit 20 through each lens 41.

  10A and 10B are diagrams showing an example of a method of positioning the substrate 10 and the lens array 40. When positioning the substrate 10 and the lens array 40, for example, as shown in FIG. 10A, the two adjacent sides of the substrate 10 and the end portions of the lens array 40 corresponding to the two sides are used as reference planes. It is brought into contact with the wall of the case 3. Then, the lens array 40 having a smaller coefficient of thermal expansion is displaced farther from the reference plane by a length corresponding to the difference Δd in the amount of expansion due to thermal expansion between the substrate 10 and the lens array 40. Due to the thermal expansion, the substrate 10 and the lens array 40 expand evenly, and the whole is expanded. Therefore, when the plurality of light emitting units 20 are turned on and the substrate 10 and the lens array 40 are thermally expanded by the above process, as shown in FIG. It becomes possible to adjust the relative position.

  Thus, the manufacturing process of the light emitting device 2 is completed. Below, the modification of the light emission part 20 is demonstrated.

  11A and 11B are a top view and a side view of the light emitting device 2A. The light emitting device 2 shown in FIGS. 2A and 2B and the light emitting device 2A shown in FIGS. 11A and 11B are different in the shape of the light emitting portion 20 and the arrangement of the inspection terminals 16. In other respects, it has the same configuration. The light emitting unit 20 of the light emitting device 2 is substantially rectangular, whereas the light emitting unit 20A of the light emitting device 2A is slightly larger than the light emitting unit 20 and is circular. As described above, the shape of each light emitting unit in the light emitting device is not limited to the rectangular shape, and may be a circular shape or another shape. The inspection terminal 16 of the light emitting device 2A is different from that of the light emitting device 2 in the distance between the two terminals for each light emitting portion 20A and the size of the angle with respect to the side of the substrate 10, but is different in other points. It has the same configuration as the device 2. The inspection terminals 16 are arranged on the substrate 10 at an interval d and an angle θ according to the shape of the light emitting portion.

12A and 12B are top views of the light emitting unit 20A. FIG. 12A shows a light emitting section 20A _{4 in} which the number of LED elements 30 connected in series is four and the number of paralleled LED elements 30 is four. In addition, FIG. 12B illustrates a light emitting unit 20A _{3 in} which the number of LED elements 30 connected in series is four and the number of paralleled LED elements 30 is three. As described above, also in the light emitting device 2A, the LED elements 30 of each light emitting unit 20A are arranged in the circular mounting area 22A having a size common to the plurality of light emitting units 20A, and the number of series and the number of parallels set for the light emitting unit 20A are set. It is mounted with the mounting density according to. In this case, the number of LED elements 30 in series, the number of parallel elements, or both may be different for each light emitting unit 20A.

FIG. 13 is a diagram schematically showing the arrangement of the LED elements 30 in the light emitting device 2B. The light emitting device 2 shown in FIG. 7 and the light emitting device 2B shown in FIG. 13 are different only in the number of series and the number of parallel LED elements 30 in each light emitting section, and have the same configuration in other points. In the light emitting device 2, the number of parallels of the respective light emitting units 20 is all the same four, but the number of series and the number of parallels may be different for each light emitting unit 20. The light emitting device 2B shown in FIG. 13 includes a light emitting unit 20B ₄ having _four serials and _four parallels, and a light emitting unit 20B3 having _three serials and five parallels. FIG. 13 shows an example in which the light emitting units 20B ₄ and the light emitting units 20B ₃ are alternately connected. Even when both the number of series and the number of parallels are changed for each light emitting unit 20, the LED element 30 of each light emitting unit 20B may be mounted in the mounting region 22 having a shape and size common to the plurality of light emitting units 20B. preferable.

  14A and 14B are top views of the light emitting device 2C and the light emitting section 20C in the light emitting device 2C. The light emitting device 2 shown in FIG. 2A and the light emitting device 2C shown in FIG. 14A are different only in the arrangement of the inspection terminals 16 of each light emitting portion, and have the same configuration in other points. In the light emitting device 2, the inspection terminals 16 of each set are arranged so as to sandwich the light emitting unit 20, but as shown in FIGS. 14 (A) and 14 (B), the inspection terminals 16 of each set are It may be arranged on one side of the light emitting unit 20C without sandwiching the light emitting unit 20C. Even in this case, the two terminals forming each set of the inspection terminals 16 are evenly arranged with a common space d between the plurality of light emitting units 20C.

  FIG. 15 is a diagram schematically showing the arrangement of the LED elements 30 in the light emitting device 2D. The light emitting device 2D shown in FIG. 15 has the same size as that of the light emitting device 2 shown in FIG. 7 except that the size of the LED element 30 differs for each light emitting section 20D. In the light emitting device 2D, the areas of the light emitting regions 22D of the respective light emitting units 20D are equal to each other, and the size of the LED element 30 included in each light emitting unit 20D is smaller as the light emitting unit 20D having a larger number of LED elements 30 in series. This makes it possible to use a lens array including a plurality of lenses having the same outer shape even if the number of elements is changed for each light emitting unit 20D. Further, by reducing the size of the element, the number of series in the light emitting region 22D having the same area can be increased, and the forward voltage of each light emitting unit 20D can be adjusted according to the number of series, so that the forward direction of the entire device can be adjusted. It is also possible to set the voltage within a range that can be driven by the driver for the light emitting device 2D. In addition, among the light emitting devices 2A to 2C described so far, the LED elements 30 having different sizes may be used for the light emitting portions having different numbers of series in this way.

  FIG. 16 is a diagram schematically showing the arrangement of the LED elements 30 in the light emitting device 2E. The light emitting device 2E shown in FIG. 16 has the same configuration as the light emitting device 2 shown in FIG. 7 in other respects, although the size of each lens 41E in the lens array 40E is different for each light emitting section 20E. The size of each lens 41E increases as the number of LED elements 30 included in the light emitting unit 20E corresponding to the lens 41E increases.

For example, the light emitting unit 20E of the light emitting device 2E includes a light emitting unit 20E ₄ (an example of a first light emitting unit) having 16 LED elements 30 that are connected in series and parallel with each other with four in series and four in parallel. It is configured with a light emitting section 20E ₃ (an example of a second light emitting section) having nine LED elements 30 connected in series and parallel with three in series and three in parallel. In the light emitting device 2E, the mounting density of the LED elements 30 is the same in each light emitting section 20E, and as a result, the size of the light emitting region 22E is different for each light emitting section 20E. The lens 41E of the light emitting device 2E is composed of a lens 41E ₄ corresponding to the light-emitting portion 20E _4, and corresponds to the light-emitting portion 20E ₃ lens 41E ₄ smaller lens 41E _3. FIG. 16 shows an example in which the light emitting units 20E ₄ and the light emitting units 20E ₃ are alternately arranged on the substrate 10. As described above, when the size of the lens 41E is changed according to the number of the LED elements 30 in each light emitting unit 20E, that is, the size of the light emitting region 22E, the small light emitting unit 20E ₃ is provided between the large light emitting units 20E _4. Can be placed. Therefore, in the light emitting device 2E, it becomes possible to form a large number of light emitting portions 20E with a higher density on the surface of the substrate 10, and the amount of emitted light increases.

  17A and 17B are a top view and a side view of the light emitting device 2F. In the light emitting device 2F shown in FIG. 17A, unlike the light emitting device 2A shown in FIG. 11A, no opening is provided in the center of the substrate 10F. The substrate 10F and the lens array 40F of the light emitting device 2F are smaller than the substrate 10 of the light emitting device 2A, and the number of light emitting units 20F of the light emitting device 2F is smaller than the number of light emitting units 20A of the light emitting device 2A. In other respects, the light emitting device 2F has the same configuration as the light emitting device 2A. The light emitting unit 20F may have the same configuration as the light emitting units 20 and 20B to 20E described above, and in this case, the opening may not be provided in the center of the substrate 10F.

  18A and 18B are a top view and a vertical sectional view of the light emitting unit 20G. More specifically, FIG. 18A is a top view of the light emitting unit 20G, and FIG. 18B is a cross-sectional view taken along the line XVIIIB-XVIIIB of FIG. 18A. FIG. 18A shows an example in which nine LED packages 30G are mounted in a 3 × 3 grid pattern. The light emitting units 20 and 20A to 20F of the above light emitting devices 2 and 2A to 2F are not limited to those in which the LED elements 30 are connected to each other with the wires 31 and the whole is sealed with the sealing resin 24, and FIG. The LED package 30G as shown in FIG. 18B may be flip-chip mounted.

  The LED package 30G has an LED element 30 'having two element electrodes 32 formed on the lower surface, and a phosphor layer 33. The LED package 30G is a bump type light emitting device in which a bump 34 for flip chip bonding is formed on a device electrode 32 on the lower surface of the LED device 30. The LED element 30 'is, for example, a blue-based semiconductor light emitting element (blue LED) that emits blue light having an emission wavelength band of about 450 to 460 nm.

  The phosphor layer 33 is formed by dispersing and mixing phosphor particles (not shown) in a colorless and transparent resin such as an epoxy resin or a silicone resin, and uniformly disperses the upper surface and the side surface of the LED element 30 ′. To coat. For example, the phosphor layer 33 contains a yellow phosphor such as YAG, and absorbs blue light emitted from the LED element 30 ′ and converts the wavelength into yellow light. In this case, the LED package 30G emits white light obtained by mixing the blue light from the LED element 30 ', which is a blue LED, with the yellow light obtained by exciting the yellow phosphor thereby. The type of phosphor contained in the phosphor layer 33 may be other than this, and may be different for each LED package 30G.

1 Lighting Device 2, 2A, 2B, 2C, 2D, 2E, 2F Light Emitting Device 10, 10F Substrate 11 Metal Substrate 12 Circuit Board 13 Opening 16 Inspection Terminal 18a, 18b Positioning Hole 20, 20A, 20B, 20C, 20D , 20E, 20F, 20G Light emitting part 22 Mounting area 23 Sealing frame 24 Sealing resin 30, 30 'LED element 30G LED package 40, 40E, 40F Lens array 41, 41E Lens 43a, 43b Support part 50 Driver

Claims (2)

Board,
A plurality of light emitting units arranged on the substrate,
A driver for driving the plurality of light emitting units,
Each of the plurality of light emitting units has a plurality of LED elements that are divided into a plurality of columns that are connected in parallel to each other and that are connected in series to each other in each of the plurality of columns,
LED elements connected in series in each of the plurality of light emitting units so that the total forward voltage of the LED elements connected in series in the plurality of light emitting units falls within the range of the voltage that can be driven by the driver. Has been set,
The smaller the number of LED elements connected in series, the higher the forward voltage of each LED element included in the light emitting section,
Ri der mutually same emission wavelength band of all the LED elements of the plurality of light emitting portions has,
Wherein the plurality of light emitting portions, that is serially connected to said driver,
A light-emitting device characterized by the above. Board,
A plurality of light emitting units arranged on the substrate,
A driver for driving the plurality of light emitting units,
Each of the plurality of light emitting units has a plurality of LED elements which are divided into a plurality of columns connected in parallel with each other and are connected in series with each other in each of the plurality of columns,
LED elements connected in series in each of the plurality of light emitting units so that the total forward voltage of the LED elements connected in series in the plurality of light emitting units falls within the range of the voltage that can be driven by the driver. Has been set,
The smaller the number of LED elements connected in series, the higher the forward voltage of each LED element included in the light emitting section,
The emission wavelength bands of all the LED elements included in the plurality of light emitting units are the same as each other,
The plurality of light emitting units are divided into a plurality of groups connected in parallel to the driver,
The light emitting units included in each of the plurality of groups are connected to each other in series.
A light-emitting device characterized by the above .

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