JP2012234724A - Led light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen difference in luminance of LED light-emitting elements for each light source unit, in an LED light source device equipped with a plurality of light source units each made up of a plurality of LED light-emitting elements connected in series.SOLUTION: A number of LED light-emitting elements 5 are arranged in line along a length direction of a substrate 4 so as to make seven pieces each of light source units 14, 15, 16, 17 connected in series on a rectangular substrate 4, with connectors 6 provided at opposite ends of the line. An anode side terminal 14a, 15a, 16a, 17a of each light source unit is arranged toward a center of the substrate 4. Power-feeding lines 18 are structured of a common line 18e extended from the connectors 6 to the center of the line, and lines connected to each anode side terminal 14a, 15a, 16a, 17a via a cross line 18f, with lengths of the lines 18a, 18b of the light source units 15, 16 positioned toward the center of the line made shortest, and with those 18c, 18d of the light source units 14, 17 toward the ends made longer.

Description

  The present invention relates to an LED light source device.

  There is known an LED light source device in which a large number of LED light emitting elements are arranged in a line along the longitudinal direction on the surface of a rectangular substrate. This type of LED light source device has the advantage that the life of the LED light source device is long because of the long life of the LED light emitting element, and the length in the short direction of the substrate can be made relatively short. Has the advantage that it can be easily stored. Further, since it has the above advantages, it is often used as a backlight of an edge light type liquid crystal television receiver.

  The configuration of the LED light source device 100 will be described with reference to FIG. In the LED light source device 100, a large number of LED light emitting elements 102 are mounted on a surface of a resin-made elongated substrate 101 in a line shape along the longitudinal direction of the substrate 101. A plurality of LED light emitting elements 102 are connected in series to constitute four light source units 103, 104, 105, 106. The anode side terminals 103a, 104a, 105a, 106a and the cathode side terminals 103b, 104b, 105b, 106b of the respective light source units 103, 104, 105, 106 are externally connected to each other through wiring patterns formed on the substrate 101. It is connected to a connector 107 to which a voltage source (not shown) is connected.

  Specifically, the anode side terminals 103a, 104a, 105a, and 106a are connected to the connector 107 via the feed lines 203, 204, 205, and 206, respectively, and the cathode side terminals 103b, 104b, 105b, and 106b are shared. It is connected to the connector 107 via a line (ground line) 207. When a voltage is applied to the connector 107, a constant positive voltage is applied to each anode side terminal 103a, 104a, 105a, 106a, a predetermined driving voltage is supplied to each LED light emitting element 102, and the LED light emitting element 102 is The light is emitted with the luminance according to the characteristics.

  Although the number of LED light emitting elements 102 connected in series as one light source unit is 7 in FIG. 6, it can be an arbitrary number depending on the use. However, if the number of LED light-emitting elements 102 connected in series as one light source unit is too small, the number of power supply lines increases and the wiring on the substrate 101 is dense, so that the LEDs connected in series as one light source unit The number of light emitting elements 102 is actually about 10 to 15.

  In addition, the lighting device (for example, refer to Patent Document 1) in which LED light emitting elements are arranged in two rows on a substrate to constitute a reading light of a writing desk, or an end portion of the substrate on which the LED light emitting elements are disposed. There is known an LED illumination assembly in which a connector is configured so that it can be easily incorporated into a cylindrical fluorescent lamp fixture (see, for example, Patent Document 2).

Japanese Patent No. 4488183 JP 2010-153383 A

  In the LED light source device 100 shown in FIG. 6, as described above, the feeder lines 203 to 206 are individually connected to the anode side terminals 103a to 106a of the light source units 103 to 106, and the same positive voltage is applied to each of them. In this way, the luminance of each LED light emitting element 102 is designed so as not to vary as much as possible. Therefore, when more LED light emitting elements 102 are arranged on the long substrate 101, the number of light source units increases.

  By the way, since the connector 107 is normally disposed at the end of the substrate 101 as shown in FIG. 6, the feeder line 203 of the anode side terminal 103a closest to the connector 107 and the anode side farthest from the anode side. The length of the terminal 106a is greatly different from that of the power supply line 206 (about four times in FIG. 6), a difference occurs in impedance loss, and a slight difference occurs in the voltage applied to the anode side terminals 103a and 106a. This causes a significant difference in the applied drive voltage between the light source units 103 and 106 located at both ends, and this voltage difference becomes a difference in the amount of current flowing through the LED light emitting element 102, resulting in a slight difference in light emission luminance. There was a problem that occurred. Specifically, there is a problem that the LED light emitting element 102 of the light source unit 106 having a long feed line 206 has lower luminance than the LED light emitting element 102 of the light source unit 103 having a short feed line 203.

  The difference in luminance becomes more significant as the distance between the light source units is larger and the difference in the length of the feeder line is larger, so that the difference in luminance is particularly remarkable in the LED light emitting elements 102 of the light source units at both ends of the long substrate 101.

  Note that the number of LED light-emitting elements 102 configured as one light source unit (connected in series) is increased to reduce the number of light source units, and the distance between the light source unit farthest from the connector 107 and the nearest light source unit is substantially reduced. It can be considered that the difference in the lengths of the feeder lines is not increased. However, in this case, since the number of the LED light emitting elements 102 connected in series as the light source unit increases, the luminance variation among the LED light emitting elements 102 in the light source unit increases.

  Accordingly, the present invention solves the above-described problem, and includes a plurality of light source units formed by connecting a plurality of LED light emitting elements in series on a substrate, and the light source units are lined along the longitudinal direction of the substrate. To provide an LED light source device capable of minimizing the difference in luminance for each light source unit as long as the length of the power supply line to each light source unit is not greatly different. Objective.

  In order to solve the above-mentioned problem, the invention of claim 1 includes a plurality of LED light-emitting elements that are arranged in a line along the longitudinal direction of a rectangular substrate and a plurality of LED light emitting elements are connected in series. A light source unit; a connector provided on the substrate and connected to an external voltage source as a driving voltage source of the LED light emitting element; and a power supply line connecting the connector and the anode side of the light source unit. In the LED light source device, the feeder line has the shortest line length for the light source unit located near the center of the line of the light source unit, and the line length increases in order toward the end of the line of the light source unit. It is characterized by being formed.

  According to a second aspect of the present invention, in the first aspect of the present invention, the line lengths of a pair of light source units at symmetrical positions across the center of the line of the light source units are the same.

  The invention according to claim 3 is the invention according to claim 1 or 2, wherein the connector is provided to face an end of a line of the light source unit, and a power supply line for each of the light source units is The light source unit is connected to the connector via a connection portion located at the center of the line of the light source unit.

  According to a fourth aspect of the present invention, in the first or second aspect of the present invention, the connector is provided so as to face a central portion of a line of the light source unit.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the feed line is a wiring pattern formed on a surface of the substrate.

  According to the first aspect of the present invention, the power supply line for supplying voltage to the plurality of light source units arranged in a line on the substrate has the shortest line length for the light source unit located near the center of the line. Since the line length increases in order toward the end of the line, the line length of the power supply line for each light source unit increases in order from one end of the line to the other end, as shown in FIG. Compared with the case where it does in this way, the difference in the length of the feeder line about each light source unit does not become large, and the difference in brightness can be made as small as possible.

  According to the invention of claim 2, since the line lengths of the pair of light source units at the symmetrical positions with respect to the center of the line are made the same, in addition to the effect of the invention of claim 1, the center of the line It is possible to prevent a difference in luminance between the light source units at symmetrical positions with respect to each other.

  According to the invention of claim 3, since the feed line for each of the light source units is connected to the connector via the connection portion located at the center of the line, the connector is provided at a position opposite to the end of the line. However, it can suppress that the difference of the length of the feeder line about each light source unit becomes large, and can make the difference in the brightness about each light source unit as small as possible.

  According to the invention of claim 4, since the connector is provided at the opposite position of the central portion of the line, the length of the line for each light source unit can be shortened, and the impedance loss is suppressed, and the LED light emitting element of each light source unit Can increase the brightness.

  According to the invention of claim 5, since the feeder line is constituted by the wiring pattern formed on the surface of the substrate, the manufacture is easy.

The front view of the state which remove | excluded the front liquid crystal panel part of the liquid crystal television receiver provided with the LED light source device which concerns on the 1st Embodiment of this invention. AA line sectional side view in FIG. The top view of the LED light source device which concerns on the 1st Embodiment of this invention. The top view of the modification of the LED light source device which concerns on the 1st Embodiment. The top view of the LED light source device which concerns on the 2nd Embodiment of this invention. The top view of the conventional LED light source device.

(First embodiment)
Hereinafter, an LED light source device according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 2, the LED light source device 1 of the present embodiment is disposed at the bottom of a box-shaped rear frame 3 as a backlight of an edge light type liquid crystal television receiver 2. In the LED light source device 1, a large number of LED light emitting elements 5 are mounted and disposed along the longitudinal direction of the substrate 4 on a resin substrate 4 having a length slightly shorter than the width W of the rear frame 3. A connector 6 connected to an external voltage source (not shown) such as a power supply circuit is provided at the end of the substrate 4.

  The light 7 emitted upward from the LED light emitting element 5 is transmitted upward by the light guide plate 8 and further diffused by the diffusion panel 9 to illuminate the front liquid crystal panel 11.

  An opening 12 is formed at the lower corner of the rear frame 3 and facing the connector 6. A flat cable 13 extending from an external voltage source is inserted through the opening 12, and the upper surface of the connector 6 is inserted. It is designed to be plugged into the mouth. Since the connector 6 is provided at the end of the substrate 4, the position where the opening 12 is formed is also the lower corner of the rear frame 3, and the amount of light leaking from the opening 12 to the rear of the rear frame 3 is reduced. This is less than when the portion 12 is near the center of the rear frame 3.

  Further, in order to improve the brightness near the center of the liquid crystal television receiver 2, the LED light emitting elements 5 may be arranged so as to be more densely arranged near the center of the substrate 4. Since 6 is located at the end of the substrate 4, it is possible to avoid an excessive increase in the density of components near the center of the substrate 4 and the density of wiring.

  As shown in FIG. 3, the LED light source device 1 constitutes light source units 14, 15, 16, and 17 in which a large number of LED light-emitting elements 5 are connected in series on a surface of a rectangular substrate 4. Thus, they are arranged in a line along the longitudinal direction of the substrate 4. In each light source unit 14, 15, 16, 17, the anode side terminals 14 a, 15 a, 16 a, 17 a are closer to the center of the substrate 4, and the cathode side terminals 14 b, 15 b, 16 b, 17 b are closer to the left and right ends of the substrate 4. Are arranged as follows.

  And the feeder line 18 which connects each anode side terminal 14a, 15a, 16a, 17a and the connector 6 is formed in the surface of the board | substrate 4 as a wiring pattern, Each cathode side terminal 14b, 15b, 16b, 17b, A line (ground line) 19 connecting the connector 6 is also formed as a wiring pattern.

  The feed line 18 has the same length of the lines 18a and 18b to the light source units 15 and 16 near the center of the line in which the light source units are arranged, and the light source units 14 and 17 located at the left and right symmetrical positions across the center of the line. The lengths of the lines 18c and 18d are equal to each other and longer than the lines 18a and 18b.

  Specifically, the common line 18e connected to the connector 6 is formed at the center of the line and extending to the center position between the light source units 15 and 16, via the connection portion 18f. It is connected to each anode side terminal 14a, 15a, 16a, 17a.

  When a voltage is applied to the connector 6 from the external voltage source, a constant positive voltage is applied to the anode side terminals 14a, 15a, 16a, and 17a through the feeder line 18, and the LED light emitting element 5 emits light. At this time, since the feeder line 18 is shorter toward the center of the line and is longer at both ends, the difference in length between the short lines 18a and 18b and the long lines 18c and 18d is different from that in the conventional apparatus shown in FIG. It is surely smaller than the difference in length between the shortest line 203 and the longest line 206.

  Specifically, in the conventional apparatus, the difference in length between the line 203 and the line 206 is about three times the length of one light source unit, but the lines 18a and 18b and the lines 18c and 18d in the present embodiment. Is substantially the same as the length of one light source unit.

  Accordingly, the difference between the voltage applied to the anode side terminals 15a and 16a and the voltage applied to the anode side terminals 14a and 17a is also the difference between the anode side terminal 103a and the anode side terminal 106a in the conventional apparatus. The difference between the luminance of the LED light emitting elements 5 of the light source units 15 and 16 and the luminance of the LED light emitting elements 5 of the light source units 14 and 17 is also small.

  Moreover, since the length of the line 18a and the line 18b is the same, the voltage applied to the anode side terminal 15a and the voltage applied to the anode side terminal 16a are exactly the same, and the LED light emitting element 5 of the light source unit 15 The luminance of the light source unit 16 is the same as that of the LED light emitting element 5. Similarly, since the lengths of the line 18c and the line 18d are the same, the brightness of the LED light-emitting element 5 of the light source unit 14 and the LED light-emitting element 5 of the light source unit 17 are the same.

  As described above, the LED light source device 1 can suppress the difference in luminance of the LED light emitting elements 5 for each of the light source units 14, 15, 16, and 17 arranged in a line as much as possible. When used as a backlight, it is possible to obtain backlight illumination with uniform luminance particularly in the left-right direction.

  When the substrate 4 is longer and the number of the LED light emitting elements 5 arranged on the substrate 4 increases and the number of the light source units increases, the light source unit extends to the left and right through the connection portion. Connect to the anode side terminal.

  A modification in the case where the number of light source units is six will be described with reference to FIG. In this case, the feeder line 21 includes a common line 21a extending from the connector 6 and a line 21c extending to the anode side terminals 31a to 36a of the light source units 31 to 36 via the connection portion 21b. As a result, the line length of the light source units 33 and 34 closer to the center is the shortest, and the light source units 32, 35, 31, and 36 closer to the end of the line become longer in order. The cathode side terminals 31 b to 36 b are connected to a common line 39.

  In the case of this modification, the connector 6 is provided to face the center of the line in which the light source units 31 to 36 are arranged, so that the length of the common line 21a is the LED light source device 1 shown in FIG. The common line 18e can be shorter than the common line 18e, and the entire length of the feeder line 21 can be shortened accordingly, and the impedance loss can be suppressed and the brightness of each LED light emitting element 5 can be increased.

(Second Embodiment)
The LED light source device 1 of 2nd Embodiment is demonstrated with reference to FIG. The LED light source device 1 of the second embodiment is different from the first embodiment in that the directions of the LED light emitting elements 5 constituting the light source units 14, 15, 16, and 17 are different from each other and each light source unit. The anode side terminals 14a, 15a, 16a, 17a of 14, 15, 16, 17 are connected to the connector 6 by individual lines.

  Specifically, in the light source units 14, 15, 16, and 17, the anode side terminals 14 a, 15 a, 16 a, and 17 a are all directed to one end (right side in FIG. 5), and the cathode side terminals 14 b, 15 b, 16 b and 17 b are arranged so as to face the other end (left side of FIG. 5) of the substrate 4. And the connector 6 is provided in the position facing the center of the line of the light source units 14, 15, 16, and 17, and the feeder line 41 connects the connector 6 and each anode side terminal 14a, 15a, 16a, 17a. It is comprised from the track | line 41a, 41b, 41c, 41d connected individually. The cathode side terminals 14 b, 15 b, 16 b and 17 b are connected to the connector 6 by a common line (ground line) 42.

  Most of the lines 41a, 41b, 41c, 41d and the line 42 are configured by a wiring pattern formed on the surface of the substrate 4, but a portion where the lines intersect is formed on the back surface of the substrate 4 through a jumper wire or a through hole. It is configured by bypassing the formed wiring pattern.

  Also in the LED light source device 1 of the present embodiment, the difference in length between the shortest line 41b and the longest line 41d is suppressed to about twice the length of one light source unit, and the impedance is correspondingly increased. The difference in loss is small, and the difference in luminance of the LED light-emitting elements 5 for each light source unit can be kept small.

  Further, since the connector 6 is arranged at the center of the line, like the LED light source device 1 shown in FIG. 4, the total length of the feeder line 41 can be shortened, and each LED light emitting element can be suppressed while suppressing the overall impedance loss. The brightness of 5 can be increased.

DESCRIPTION OF SYMBOLS 1 LED light source device 4 Board | substrate 5 LED light emitting element 6 Connector 14,15,16,17 Light source unit 14a, 15a, 16a, 17a Anode side terminal 18 Feed line 18a, 18b, 18c, 18d Line 18f Connection part 21 Feed line 21b Connection Units 31, 32, 33, 34, 35, 36 Light source units 31a, 32a, 33a, 34a, 35a, 36a Anode side terminal 41 Feed lines 41a, 41b, 41c, 41d

Claims (5)

A plurality of light source units arranged in a line along the longitudinal direction of the substrate on the surface of the rectangular substrate, and a plurality of LED light emitting elements connected in series;
A connector provided on the substrate and connected to an external voltage source as a driving voltage source of the LED light emitting element;
In an LED light source device comprising: a power supply line that connects the connector and the anode side of the light source unit;
The feeder line is formed so that the line length of the light source unit located near the center of the line of the light source unit is the shortest, and the line length becomes longer in order toward the end of the line of the light source unit. An LED light source device.   2. The LED light source device according to claim 1, wherein the line lengths of the pair of light source units at symmetrical positions across the center of the line of the light source unit are the same.   The connector is provided opposite to an end of a line of the light source unit, and a feed line for each of the light source units is connected to the connector via a connection portion located at the center of the line of the light source unit. The LED light source device according to claim 1, wherein the LED light source device is provided.   The LED light source device according to claim 1, wherein the connector is provided so as to face a central portion of a line of the light source unit.   The LED light source device according to any one of claims 1 to 4, wherein the power supply line is a wiring pattern formed on a surface of the substrate.

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