JP7321358B2 - Light emitting device and lighting device - Google Patents

Description

The present disclosure relates to light emitting devices and lighting devices.

A light-emitting device that independently drives light emission of a plurality of light-emitting element arrays such as light-emitting diodes (LEDs) by supplying currents separately from each of a plurality of electrode pairs to the plurality of light-emitting element arrays. known (see, for example, JP-A-2016-119381 and JP-A-2017-120897). The light emitting devices described in JP-A-2016-119381 and JP-A-2017-120897 adjust the chromaticity of the emitted light by adjusting the current value of the current supplied from the plurality of electrode pairs. be able to. However, in the light-emitting devices described in Japanese Patent Application Laid-Open Nos. 2016-119381 and 2017-120897, current is supplied from a plurality of electrode pairs to the light-emitting element array, so the electrode area becomes large and the size of the light-emitting device becomes large. becomes large, the shape of the wiring pattern becomes complicated, and there is a possibility that the design cost increases.

International Publication No. WO 2016/039344 discloses a pair of electrode pairs, two LED columns to which current is supplied from the pair of electrode pairs, and one LED column of the two LED columns with current only when the voltage is low. and a current control circuit for controlling the current to flow. The LED light emitting device described in International Publication No. 2016/039344 supplies a current from a pair of electrode pairs to two LED rows collectively, and supplies current to one LED row only when the voltage is low. By controlling the current, it is possible to change the emission color when the incandescent electrode is dimmed.

However, in the light-emitting device described in International Publication No. 2016/039344, when the applied voltage increases, the current stops flowing through one of the two LED rows, and the LEDs included in both of the two LED rows Light mixed with emitted light is not emitted.

An object of the present disclosure is to solve such problems, and to provide a light-emitting device capable of setting current values of currents supplied from a pair of electrode pairs to a plurality of light-emitting element arrays at a predetermined ratio. do.

A light-emitting device according to the present disclosure includes a pair of electrodes, a first light-emitting element group that emits light when a current is supplied from the pair of electrodes, and a pair of light-emitting elements connected in parallel to the first light-emitting element group. When a current is supplied from the electrode pair, the second light emitting element group that emits light, the current value of the first current flowing through the first light emitting element group, and the current value of the second current flowing through the second light emitting element group are a reference voltage generation circuit that generates a reference voltage used to control one of the current values of the first current and the second current so as to achieve a predetermined ratio; a current control circuit that controls one of the two currents and does not control the other of the first current and the second current.

Further, in the light emitting device according to the present disclosure, the reference voltage includes a second reference voltage used to control the current value of the second current, and the current control circuit controls the second reference voltage based on the second reference voltage. It is preferable to include a second current control circuit for controlling the second current such that the current value of the current has a predetermined ratio to the current value of the first current.

Furthermore, in the light emitting device according to the present disclosure, the first light emitting element group emits light of a first color, and the second light emitting element group emits light of a second color different from the first color. is preferred.

Furthermore, the light-emitting device according to the present disclosure is connected in parallel to the first light-emitting element group and the second light-emitting element group, and emits light of either the first color or the second color when current is supplied from the pair of electrodes. The third light emitting element group that emits light of a third color different from the third light emitting element group and the third light emitting element group are controlled so that the current value of the third current flowing through the third light emitting element group has a predetermined ratio with respect to the current value of the first current. and a third current control circuit for controlling three currents, wherein the reference voltages preferably further include a third reference voltage used to control the current value of the third current.

Further, in the light emitting device according to the present disclosure, the reference voltage generation circuit has a second resistor pair connected in series with the first light emitting element group, and the divided voltage obtained by dividing the voltage by the second resistor pair is used as the second reference voltage. Preferably, it is output as a voltage to the second current control circuit.

Furthermore, in the light emitting device according to the present disclosure, one resistor included in the second resistor pair is preferably a variable resistor.

Furthermore, in the light-emitting device according to the present disclosure, the second current control circuit includes a second switch having one end connected to the last-stage light-emitting element of the second light-emitting element group and one end connected to the other end of the second switch. The second detection resistor, the input second reference voltage, and the second detection voltage applied to the second detection resistor are compared so that the second reference voltage matches the second detection voltage. and a second comparator controlling two switches.

Further, in the light emitting device according to the present disclosure, the reference voltage generation circuit further includes a third resistance pair connected in parallel with the second resistance pair, and the divided voltage obtained by dividing the voltage by the third resistance pair is the third reference voltage. Preferably, it is output as a voltage to the third current control circuit.

Furthermore, in the light-emitting device according to the present disclosure, one resistor included in the third resistor pair is preferably a variable resistor.

Further, in the light emitting device according to the present disclosure, the first light emitting element group, the second light emitting element group, and the third light emitting element group are connected in parallel, and when current is supplied from the pair of electrodes, the first color, A fourth light emitting element group that emits light of a fourth color different from any of the second color and the third color, and the current value of the fourth current flowing through the fourth light emitting element group equals the current value of the first current. and a fourth current control circuit for controlling the third current so as to have a predetermined ratio with respect to the Further comprising, the first color light is preferably white.

Further, in the light-emitting device according to the present disclosure, the reference voltage generation circuit can control the first current such that the current value of the first current has a predetermined ratio with respect to the current value of the second current. a control circuit; and a second current control circuit capable of controlling the second current such that the current value of the second current has a predetermined ratio with respect to the current value of the first current, wherein the reference voltage generation circuit is , the reference voltage is preferably generated such that the current value of one of the first current and the second current has a predetermined ratio to the current value of the other of the first current and the second current.

Furthermore, in the light emitting device according to the present disclosure, the first light emitting element group emits light of a first color, and the second light emitting element group emits light of a second color different from the first color. is preferred.

Further, in the light-emitting device according to the present disclosure, the forward voltage of one of the first light-emitting element group and the second light-emitting element group whose current value is controlled is It is preferable that the reference voltage generation circuit generates the reference voltage such that the current values of the first current and the second current are desired values.

Further, the light emitting device according to the present disclosure includes a pair of electrode pairs, a plurality of light emitting element groups connected in parallel and each emitting light when current is supplied from the pair of electrode pairs, and a plurality of light emitting element groups. It has a plurality of transistors each having one of its collector and emitter connected to each of the groups, and a switching element for shorting or opening between the base and collector of each of the plurality of transistors.

Furthermore, in the light emitting device according to the present disclosure, any one of the plurality of transistors is short-circuited between the base and the collector via the switching element, and the other of the plurality of transistors is short-circuited between the base and the collector via the switching element. It is preferable that the gap between is opened.

Furthermore, in the light-emitting device according to the present disclosure, the forward voltage of the light-emitting element group connected in series with the transistor whose base and collector are short-circuited via the switching element is the forward voltage of the transistor whose base and collector are open-circuited. is preferably higher than the forward voltage of the light emitting element group connected in series with .

Further, in the light emitting device according to the present disclosure, the reference voltage generation circuit includes a second resistance pair connected in series with the first light emitting element group, and a third resistance pair connected in parallel with the second resistance pair. One resistor of each of the resistor pair and the third resistor pair has a first contact connected to the other of the second resistor pair, a second contact connected to the other of the third resistor pair, the first contact and the second contact. and a movable contact that can be connected to any position of the resistor, and a third contact that is connected to the movable contact.

The lighting device according to the present disclosure includes an operating member formed with an internal gear, a cylindrical shaft, a first gear disposed at one end of the shaft and screwed to the internal gear, and disposed at one end of the shaft. and a third gear that is screwed into the second gear. According to the rotation of the third gear, the ratio of current flowing through the second light emitting element group and the and the light emitting device described above, wherein when the third gear rotates in accordance with the rotation of the operation member in the first direction, the movable contact moves such that the first voltage dividing resistance decreases and the third voltage dividing resistance increases, and the third gear rotates in response to rotation of the operating member in a second direction opposite to the first direction. , the movable contact moves such that the first voltage dividing resistance increases and the third voltage dividing resistance decreases.

The light-emitting device according to the present disclosure can set current values of currents supplied from a pair of electrode pairs to a plurality of light-emitting element arrays at a predetermined ratio.

1 is a perspective view of a lighting device equipped with a light emitting device according to a first embodiment; FIG. FIG. 2 is an exploded perspective view of the lighting device shown in FIG. 1; 1 is a circuit block diagram of a light emitting device according to a first embodiment; FIG. FIG. 11 is a perspective view of a lighting device equipped with a light emitting device according to a second embodiment; FIG. 5 is a see-through perspective view of a light emitting device, a diffusion member, and a current adjusting unit included in the lighting device shown in FIG. 4; FIG. 4 is a circuit block diagram of a light emitting device according to a second embodiment; 7 is a diagram showing a first voltage dividing resistor and a third voltage dividing resistor shown in FIG. 6; FIG. 7 is a diagram showing changes in the current ratios of the first current, the second current, and the third current when the resistance ratios of the first voltage dividing resistor and the third voltage dividing resistor shown in FIG. 6 are changed; FIG. 7 is a chromaticity diagram showing optical characteristics of light emitted from the light emitting device shown in FIG. 6. FIG. FIG. 11 is a circuit block diagram of a light emitting device according to a third embodiment; 11 is a diagram showing first voltage dividing resistors and third voltage dividing resistors shown in FIG. 10; FIG. 11 is a chromaticity diagram showing optical characteristics of light emitted from the light emitting device shown in FIG. 10; FIG. FIG. 11 is a circuit block diagram of a light emitting device according to a fourth embodiment; 8 is a chromaticity diagram showing changes in chromaticity of light emitted from the light emitting device shown in FIG. 7 when a first reference voltage, a second reference voltage, and a third reference voltage are changed; FIG. FIG. 11 is a circuit block diagram of a light emitting device according to a fifth embodiment; 16 is a chromaticity diagram showing optical characteristics of light emitted from the light emitting device shown in FIG. 15. FIG. FIG. 11 is a circuit block diagram of a light emitting device according to a sixth embodiment; (a) is a diagram showing an example of a light emitting state of a conventional light emitting device, and (b) is a diagram showing an example of a light emitting state of a light emitting device 6. FIG.

A light emitting device according to the present disclosure will be described below with reference to the drawings. However, it should be noted that the technical scope of the present disclosure is not limited to those embodiments, but extends to the invention described in the claims and equivalents thereof.

(Structure and Function of Lighting Apparatus Mounting Light Emitting Device According to First Embodiment)
FIG. 1 is a perspective view of a lighting device equipped with a light emitting device according to the first embodiment, and FIG. 2 is an exploded perspective view of the lighting device shown in FIG.

A lighting device 110 according to the first embodiment includes a first housing 111, a second housing 112, a connector 113, a heat dissipation sheet 114, a light emitting device 1, a first reflecting member 115, and a diffusion member 116. , a sealing member 117 and a second reflecting member 118. FIG.

The first housing 111 is formed by drawing metal with high thermal conductivity such as aluminum, and accommodates the second housing 112 , the heat dissipation sheet 114 , the light emitting device 1 and the first reflecting member 115 . The second housing 112 is made of an insulating resin material such as polybutylene terephthalate. The second housing 112 is arranged along the inner wall of the first housing 111 and improves insulation properties between the electronic components mounted on the light emitting device 1 and the first housing 111 . In addition, the second housing 112 is formed with a hole into which the heat dissipation sheet 114 can be inserted in a portion corresponding to the supporting portion in which the first housing 111 supports the light emitting device 1 . The connector 113 has a pair of power supply terminals connectable to an external power supply, and supplies power to electronic components mounted on the light emitting device 1 .

The heat dissipation sheet 114 is a heat dissipation material made of synthetic resin material with high thermal conductivity such as silicon resin. The heat dissipation sheet 114 is arranged between the first housing 111 and the light emitting device 1 and radiates heat generated while the light emitting device 1 emits light to the first housing 111 . The light-emitting device 1 is mounted with a light-emitting element such as an LED and an electronic member, and emits light when a power supply voltage is supplied through the connector 113 . The light-emitting device 1 is mounted with electronic components forming a power supply circuit for supplying power to light-emitting elements mounted on the light-emitting device 1 .

The first reflecting member 115 is an inverted conical member having an opening at the bottom made of a highly reflective synthetic resin material such as polycarbonate resin. It is supported and arranged to cover the light emitting device 1 . An inner wall of the first reflecting member 115 is a reflecting surface that reflects light emitted from the light emitting device 1 . The diffusion member 116 is an arc-shaped member made of a synthetic resin material such as polycarbonate, and has an outer edge supported by the first reflection member 115 . The diffusion member 116 has a diffusion surface in which at least one of the front surface and the back surface is textured, and diffuses and emits the light incident from the light emitting device 1 via the first reflection member 115 . The sealing member 117 , also called packing, is a ring-shaped member made of a synthetic rubber material such as nitrile rubber, and is arranged between the diffusing member 116 and the second reflecting member 118 . The second reflecting member 118 is a mortar-shaped member made of a highly reflective member such as aluminum, supported by the diffusion member 116 via the sealing member 117, and supported by the first housing 111 at its outer edge. be. The inner wall 57 of the second reflecting member 118 is a reflecting surface that reflects the light emitted from the light emitting device 1 .

(Structure and Function of Light Emitting Device According to First Embodiment)
FIG. 3 is a circuit block diagram of the light emitting device according to the first embodiment. The constituent elements of the light emitting device according to the first embodiment shown in FIG. 3 are mounted on a single circuit board 1a shown in FIG.

The light emitting device 1 includes a power supply circuit 10, a first light emitting element group 11, a second light emitting element group 12, a third light emitting element group 13, a reference voltage generation circuit 20, a second current control circuit 30, It has a third current control circuit 35 , a first electrode 101 and a second electrode 102 .

The power supply circuit 10 has a supply resistor 103, a supply Zener diode 104, a supply transistor 105, and a supply capacitor 106, and power supplies for the operational amplifiers 33 and 38 of the second current control circuit 30 and the third current control circuit 35. Generate voltage Vdd.

One end of the supply resistor 103 is connected to the first electrode 101 and the other end of the supply resistor 103 is connected to the cathode of the supply Zener diode 104 and the base of the supply transistor 105 . The anode of the supply Zener diode 104 is connected to the second electrode 102 . The collector of source transistor 105 is connected to the first electrode and the emitter of source transistor 105 is connected to one end of source capacitor 106 . The other end of supply capacitor 106 is connected to second electrode 102 .

The power supply circuit 10 supplies the power supply voltage Vdd having a predetermined voltage value to the operational amplifiers 33 and 38 of the second current control circuit 30 and the third current control circuit 35 by charging the supply capacitor 106 .

The first light emitting element group 11 includes three first light emitting element columns 15 formed by six serially connected first light emitting elements 14 . Each of the plurality of first light emitting elements 14 is an LED die that emits light of a first color, for example green. The number of the first light emitting elements 14 included in the first light emitting element row 15 may be 1 or 2 or more, and the number of the first light emitting element rows 15 may be 1, 2 or 4 or more. The first light emitting element 14 contains an LED die that emits blue light and a light conversion material such as a phosphor such as YAG (Yttrium Aluminum Garnet) that converts the blue light emitted from the LED die into green. and a sealing material for sealing the LED die.

The second light emitting element group 12 includes three second light emitting element columns 17 formed by four second light emitting elements 16 connected in series. Each of the plurality of second light emitting elements 16 is an LED die that emits light of a second color different from the first color green, for example blue. The number of the second light emitting elements 16 included in the second light emitting element row 17 may be 1 or 2 or more as long as it is less than the number of the serially connected first light emitting elements 14 included in the first light emitting element row 15. The number of second light emitting element rows 17 may be one, two, or four or more.

The third light emitting element group 13 includes three third light emitting element columns 19 formed by four third light emitting elements 18 connected in series. Each of the plurality of third light emitting elements 18 is an LED die that emits light of a third color, for example red, different from both the first color green and the second color blue. The number of the third light emitting elements 18 included in the third light emitting element row 19 may be 1 or 2 or more as long as it is less than the number of the serially connected first light emitting elements 14 included in the first light emitting element row 15. The number of third light emitting element rows 19 may be one, two, or four or more. Further, the third light emitting element 18 contains an LED die that emits blue light and a light conversion material such as CASN such as a phosphor that converts the blue light emitted from the LED die into red. The light-emitting element may also have a sealing material that seals the .

The reference voltage generation circuit 20 is a voltage dividing circuit having a first detection resistor 21 , a second resistor pair 22 and a third resistor pair 23 . The reference voltage generation circuit 20 generates a second reference voltage V used for controlling the current values of the second current _I2 flowing through the second light emitting element group 12 and the third current _I3 flowing through the third light emitting element group 13. ₂ and a third reference voltage _V3 . The second current _I2 and the third current _I3 are obtained when the magnitude of the resistor 21, the resistor 32, and the resistor 37 are equal to the current value of the first current _I1 flowing through the first light emitting element group 11. is controlled to have a predetermined ratio smaller than the first current _I1 . The first detection resistor 21 is a resistance element having a resistance value of several Ω, one end of which is connected to the first light emitting element group 11 and the other end of which is grounded. The first detection resistor 21 detects the voltage applied across it as a first reference voltage _V1 .

The second resistor pair 22 has a first voltage dividing resistor 24 and a second voltage dividing resistor 25 and is connected in parallel to the first detection resistor 21 . One end of the first voltage dividing resistor 24 is connected to one end of the first detection resistor 21 and the first light emitting element group 11 , and the other end of the first voltage dividing resistor 24 is connected to one end of the second voltage dividing resistor 25 . The other end of the second voltage dividing resistor 25 is grounded together with the other end of the first detection resistor 21 . Each resistance value of the first voltage dividing resistor 24 and the second voltage dividing resistor 25 is approximately several kΩ, which is larger than the resistance value of the first detection resistor 21 .

The third resistor pair 23 has a third voltage dividing resistor 26 and a fourth voltage dividing resistor 27 and is connected in parallel to the first detection resistor 21 and the second resistor pair 22 . One end of the third voltage dividing resistor 26 is connected to the first light emitting element group 11 together with one ends of the first detection resistor 21 and the first voltage dividing resistor 24 , and the other end of the third voltage dividing resistor 26 is connected to the fourth voltage dividing resistor 27 . is connected to one end of the The other end of the fourth voltage dividing resistor 27 is grounded together with the other ends of the first detection resistor 21 and the second voltage dividing resistor 25 . Each resistance value of the third voltage dividing resistor 26 and the fourth voltage dividing resistor 27 is about several kΩ, and the resistance value of the first detection resistor 21 is similar to that of the first voltage dividing resistor 24 and the second voltage dividing resistor 25. bigger than

The reference voltage generation circuit 20 converts the voltage at the connection between the first voltage dividing resistor 24 and the second voltage dividing resistor 25 into a second reference voltage _V2 which is the voltage divided by the second resistor pair 22. Output to the second current control circuit 30 . The reference voltage generation circuit 20 divides the voltage at the connection between the third voltage dividing resistor 26 and the fourth voltage dividing resistor 27 by the third resistor pair 23 to obtain a third reference voltage V ₃ to the third current control circuit 35 .

The second current control circuit 30 has a second switch 31 , a second detection resistor 32 and a second comparator 33 . The second switch 31 is an nMOSFET, one end of which is the drain is connected to the second light emitting element group 12, the other end of the source is connected to one end of the second detection resistor 32, and the second switch 31 is the control terminal of the gate. It is connected to the output terminal of the comparator 33 . The other end of the second detection resistor 32 is grounded. A first input terminal of the second comparator 33 is connected to the other end of the first voltage dividing resistor 24 and one end of the second voltage dividing resistor 25, and receives the second reference voltage _V2 . A second input terminal of the second comparator 33 is connected to one end of the second detection resistor 32 and receives a second detection voltage V _D2 that is the voltage across the second detection resistor 32 . The second comparator 33 compares the input second reference voltage _V2 with the second detection voltage _VD2 applied to the second detection resistor 32, and the second reference voltage _V2 becomes the second detection voltage V. The second switch 31 is controlled so as to match _D2 .

The third current control circuit 35 has a third switch 36 , a third detection resistor 37 and a third comparator 38 . The third switch 36 is an nMOSFET, one end of the drain is connected to the third light emitting element group 13, the other end of the source is connected to one end of the third detection resistor 37, and the control terminal of the gate is the third switch. It is connected to the output terminal of the comparator 38 . The other end of the third detection resistor 37 is grounded. A first input terminal of the third comparator 38 is connected to the other end of the third voltage dividing resistor 26 and one end of the fourth voltage dividing resistor 27, and receives the third reference voltage _V3 . A second input terminal of the third comparator 38 is connected to one end of the third detection resistor 37 and receives a third detection voltage V _D3 that is the voltage across the third detection resistor 37 . The third comparator 38 compares the input third reference voltage _V3 with the third detection voltage _VD3 applied to the third detection resistor 37, and the third reference voltage _V3 becomes the third detection voltage V. Control the third switch 36 to match _D3 .

Each of the first electrode 101 and the second electrode 102 is connected to a current source 100, and the current supplied from the current source 100 is applied to the first light emitting element group 11, the second light emitting element group 12, and the third light emitting element group 13. supply each. The current source 100 is a variable constant current power supply that can change the current supplied to the first electrode 101 .

In the light emitting device 1, the current values of the second current I2 flowing through the second light emitting element group ₁₂ and the third current I3 flowing through the third light emitting element group ₁₃ are equal to the current values of the first current I1 flowing through the first light emitting element group ₁₁ . The second current _I2 and the third current _I3 are controlled so as to have a predetermined ratio with respect to the current value. The second current control circuit 30 and the third current control circuit 35 control the second current I so that the second reference voltage _V2 and the third reference voltage _V3 have a predetermined ratio to the first reference voltage _V1 . ₂ and the third current _I3 are feedback controlled. The second current I flowing through the second _light emitting element group 12 and the third light emitting element group 13 is caused by the second reference voltage V2 _and the third reference voltage _V3 having a predetermined ratio with respect to the first reference voltage V1. ₂ and the third current I ₃ have a predetermined ratio with respect to the first current I ₁ flowing through the first light emitting element group 11 .

For example, when the ratios of the second reference voltage _V2 and the third reference voltage _V3 to the first reference voltage _V1 are 3/5 and 2/5, the second current control circuit 30 and the third current control circuit 35 are , the second current _I2 and _{the third} current _I3 are controlled so that the ratios to the first current I1 are 3/5 and 2/5.

(Action and effect of the light emitting device according to the first embodiment)
The light emitting device 1 controls the second current _I.sub.2 and the third current _I.sub.3 to have a predetermined ratio with respect to the first current _I.sub.1 . A desired ratio of the light emitted from the can be emitted regardless of the current supplied. Since the light-emitting device 1 fixes the ratio of the current rather than the absolute value of the current, even if the current input from the current source 100 changes due to dimming or the like, the first light-emitting element group 11 to the third light-emitting element group 13 is kept constant.

In the light-emitting device 1, electronic components including the power supply circuit 10 are mounted on a single circuit board 1a. The device 110 can mount various light emitting devices in the same housing.

(Structure and Function of Lighting Device Mounting Light Emitting Device According to Second Embodiment)
FIG. 4 is a perspective view of a lighting device equipped with a light emitting device according to the second embodiment, and FIG. 5 is a see-through perspective view of the light emitting device, diffusion member, and current adjusting section included in the lighting device shown in FIG.

A lighting device 120 according to the second embodiment has a light emitting device 2 and a diffusion member 126, which is an example of an operating member having an internal gear 126a formed near the upper end, instead of the light emitting device 1 and the diffusion member 116. It differs from device 110 . Moreover, the lighting device 120 differs from the lighting device 110 in that it has a rotating member 121 and a current adjusting section 127 . The configuration and function of the constituent elements of the lighting device 120 other than the rotating member 121, the light emitting device 2, the diffusion member 126, and the current adjusting section 127 are the same as those of the constituent elements of the lighting device 110 denoted by the same reference numerals. Detailed description is omitted here.

The rotating member 121 has a shaft portion 122 , a first gear 123 and a second gear 124 . The shaft portion 122 is a cylindrical member extending in the normal direction of the circuit board 2 a of the light emitting device 2 , and is arranged so as to pass through a through hole formed in the first reflecting member 115 . The shaft portion 122 has a first gear 123 arranged at its upper end and a second gear 124 arranged at its lower end. The first gear 123 is screwed into an internal gear 126 a formed on the inner wall of the upper end of the diffusion member 126 . The second gear 124 is an internal gear formed inside the lower end of the shaft portion 122 and is screwed to the current adjusting portion 127 .

The current adjustment unit 127 has a third gear 128 that is screwed with the second gear 124, and according to the rotation of the third gear 128, the ratio of the current flowing through the second light emitting element group 12 and the third light emission It is a current adjusting device that adjusts the ratio of the current flowing through the element group 13 .

When the diffusion member 126 is rotated by the operator in the direction indicated by the arrow A, the third gear 128 rotates via the rotation member 121, increasing the ratio of the current flowing through the second light emitting element group 12, The ratio of the current flowing through the three light emitting element group 13 is reduced. On the other hand, when the diffusion member 126 is rotated by the operator in the direction opposite to the direction indicated by the arrow A, the ratio of the current flowing through the second light emitting element group 12 decreases and the current flowing through the third light emitting element group 13 decreases. ratio increases.

(Structure and Function of Light Emitting Device According to Second Embodiment)
FIG. 6 is a circuit block diagram of the light emitting device 2 according to the second embodiment.

The light emitting device 2 differs from the light emitting device 1 in that it has a reference voltage generation circuit 40 instead of the reference voltage generation circuit 20 . The configurations and functions of the components of the light-emitting device 2 other than the reference voltage generation circuit 40 are the same as the configurations and functions of the components of the light-emitting device 1 denoted by the same reference numerals, so detailed descriptions thereof are omitted here.

The reference voltage generation circuit 40 differs from the reference voltage generation circuit 20 in that it has a second resistance pair 42 and a third resistance pair 43 instead of the second resistance pair 22 and the third resistance pair 23 . A second resistor pair 42 has a first voltage dividing resistor 44 in place of the first voltage dividing resistor 24 and a third resistor pair 43 has a third voltage dividing resistor 46 in place of the third voltage dividing resistor 26 . The configurations and functions of the components of the reference voltage generating circuit 40 other than the first voltage dividing resistor 44 and the third voltage dividing resistor 46 are the same as the configurations and functions of the components of the reference voltage generating circuit 20 to which the same reference numerals are assigned. , detailed description is omitted here.

FIG. 7 is a diagram showing the first voltage dividing resistor 44 and the third voltage dividing resistor 46. As shown in FIG.

The first voltage dividing resistor 44 and the third voltage dividing resistor 46 are integrated by a resistor 400 , a first terminal 401 , a second terminal 402 , a third terminal 403 and a movable contact 404 . The resistor 400 is a high-resistance conductor such as a nickel-chromium alloy, has a first terminal 401 connected to the second voltage dividing resistor 25 at one end, and a first terminal 401 connected to the fourth voltage dividing resistor 27 . Two terminals 402 are located at the other end. The movable contact 404 is a conductor that has a third terminal 403 connected to the first light emitting element group 11 arranged at one end thereof and that can be connected to an arbitrary position of the resistor 400 . The resistance values of the first voltage dividing resistor 44 and the third voltage dividing resistor 46 change continuously according to the location where the movable contact 404 contacts the resistor 400 .

The movable contact 404 moves as the third gear 128 of the current adjusting section 127 rotates. As the third gear 128 rotates in response to the diffusion member 126 being rotated in the first direction indicated by arrow A, the movable contact 404 causes the first voltage dividing resistor 44 to decrease and the third voltage dividing resistor 46 to increase. to move. By moving such that the first voltage dividing resistor 44 decreases and the third voltage dividing resistor 46 increases, the ratio of the current flowing through the second light emitting element group 12 increases and the current flowing through the third light emitting element group 13 increases. The rate of current decreases.

Also, when the third gear 128 rotates in response to the rotation of the diffusion member 126 in a second direction opposite to the first direction shown by arrow A, the movable contact 404 increases the first voltage dividing resistance 44 and The third voltage dividing resistor 46 moves to decrease. By moving such that the first voltage dividing resistor 44 increases and the third voltage dividing resistor 46 decreases, the ratio of the current flowing through the second light emitting element group 12 decreases and the current flowing through the third light emitting element group 13 decreases. The current ratio increases.

(Action and effect of the light emitting device according to the second embodiment)
In the light emitting device 2, the reference voltage generating circuit 40 has the first voltage dividing resistor 44 and the third voltage dividing resistor 46 which are variable resistors, so that the first reference voltage of the second reference voltage _V2 and the _third reference voltage V3 The ratio to V ₁ can be varied continuously. By changing the ratio of the second reference voltage _V2 and the third reference voltage _V3 to the first reference voltage _V1 , the light emitting device 2 generates a second current flowing through the second light emitting element group 12 and the third light emitting element group 13. The ratio of _I2 and the third current _I3 to the first current _I1 flowing through the first light emitting element group 11 can be changed continuously.

FIG. 8 shows changes in current ratios of the first current I ₁ , the second current I ₂ and the third current I ₃ when the resistance ratios of the first voltage dividing resistor 44 and the third voltage dividing resistor 46 are changed. It is a figure which shows. In FIG. 8, the abscissa indicates the steps of resistance of the first voltage dividing resistor 44 and the third voltage dividing resistor 46, and the ordinate indicates each of the first current I ₁ , the second current I ₂ and the third current I _{3 .} Current ratio [%] is shown. In FIG. 8, diamond marks indicate the first current _I1 flowing through the first light emitting element group 11, triangle marks indicate the second current _I2 flowing through the second light emitting element group 12, and square marks indicate the third light emitting element group. 13 shows a third current I ₃ flowing through 13;

When the resistance step is "0", the first current _I1 and the third current _I3 are 45%, and the second current _I2 is 10%. As the resistance step increases, the second current _I2 increases and the third current _I3 decreases; when the resistance step is "10", the first current _I1 and the second current _I2 are 45% and the third current _I3 becomes 10%. The maximum value, the minimum value, and the intermediate value between them of the second current and the third current can be adjusted by changing the value of the resistor 25 or the resistor 27, for example.

In the light-emitting device 2, the current value of the first current I1 corresponding to the first light-emitting element group ₁₁ that emits green light is the same as that of the second light-emitting element group 12 and the third light-emitting element group that emit blue and red light. 13 is greater than the respective current values of the second current I ₂ and the third current I ₃ corresponding to 13. Further, in the light emitting device 2, the current value of the third current _I3 decreases as the current value of the second current _I2 increases. The light emitting device 2 adjusts the wavelength of the light emitted from the first light emitting element 14, the second light emitting element 16, and the third light emitting element 18, and the light emitted from the second light emitting element 16 and the third light emitting element 18 is adjusted. By changing the ratio of light, light can be emitted along the black body locus.

FIG. 9 is a chromaticity diagram showing optical characteristics of light emitted from the light emitting device 2. As shown in FIG. In FIG. 9, a thin curve L20 indicates the black body locus. A point P21 indicates the chromaticity of light emitted from the first light emitting element group 11, a point P22 indicates the chromaticity of light emitted from the second light emitting element group 12, and a point P23 indicates the chromaticity of light emitted from the 13th light emitting element group 13. Indicates the chromaticity of emitted light. A thick curve L24 indicates an effective color gamut indicating the chromaticity of light that the light emitting device 2 can emit.

The light emitting device 2 can emit light having chromaticity that matches the blackbody locus over a predetermined color gamut. The light emitting device 2 is adjusted so that the light emitted from the first light emitting element group 11 to the third light emitting element group 13 has a color deviation (Duv) of ±0.01 or less with respect to the black body locus. can do.

(Structure and Function of Light Emitting Device According to Third Embodiment)
FIG. 10 is a circuit block diagram of a light emitting device according to the third embodiment.

The light emitting device 3 differs from the light emitting device 2 in that it has a reference voltage generation circuit 50 instead of the reference voltage generation circuit 40 . Further, the light emitting device 3 differs from the light emitting device 2 in that it further includes a current ratio control circuit 60 . The configurations and functions of the components of the light-emitting device 3 other than the reference voltage generation circuit 50 and the current ratio control circuit 60 are the same as the configurations and functions of the components of the light-emitting device 2 denoted by the same reference numerals. are omitted.

The reference voltage generation circuit 50 differs from the reference voltage generation circuit 40 in that it has a second resistance pair 52 and a third resistance pair 53 instead of the second resistance pair 42 and the third resistance pair 43 . The second resistor pair 52 has a first voltage dividing resistor 54 in place of the first voltage dividing resistor 44 and the third resistor pair 53 has a third voltage dividing resistor 56 in place of the third voltage dividing resistor 46 . The configurations and functions of the components of the reference voltage generation circuit 50 other than the first voltage dividing resistor 54 and the third voltage dividing resistor 56 are the same as the configurations and functions of the components of the reference voltage generation circuit 40 denoted by the same reference numerals. , detailed description is omitted here.

FIG. 11 is a diagram showing the first voltage dividing resistor 54 and the third voltage dividing resistor 56. As shown in FIG.

The first voltage dividing resistor 54 and the third voltage dividing resistor 56 are integrated by a resistor 500 , a first terminal 501 , a second terminal 502 , a third terminal 503 , a plurality of switches 504 and an input terminal 505 . The resistor 500 is a high-resistance conductor such as a nickel-chromium alloy, has a first terminal 501 connected to the second voltage dividing resistor 25 at one end, and a first terminal 501 connected to the fourth voltage dividing resistor 27 . Two terminals 502 are located at the other end. Each of the plurality of switches 504 is, for example, an nMOSFET, has a drain connected to a third terminal 503 connected to the first light emitting element group 11, has a source connected to the resistor 500, and is connected to the current ratio control circuit 60. A gate is connected to an input terminal 505 that The resistance values of the first voltage dividing resistor 54 and the third voltage dividing resistor 56 change continuously according to the position of the switch 504 that is turned on.

The current ratio control circuit 60 has a communication section 61 , a storage section 62 , a control section 63 and an output section 64 .

The communication unit 61 is a communication interface or the like such as I2C, and is electrically connected to a host controller (not shown) that controls communication of the light emitting device 3 . The communication unit 61 has pads for connecting with an external device such as a host controller. The pads of the communication section 61 are arranged on the surface of the substrate forming the light emitting device 3, for example. By arranging the pads of the communication unit 61 on the surface of the substrate, the light emitting device 3 can reduce the number of wires.

The storage unit 62 includes, for example, a semiconductor memory device such as ROM (Read Only Memory) and RAM (Random Access Memory). The storage unit 62 stores an operating system program, a driver program, a control program, data, and the like used for processing in the control unit 63 .

The control unit 63 has one or more processors and their peripheral circuits, and controls the resistance ratio between the first voltage dividing resistor 54 and the third voltage dividing resistor 56. For example, a CPU (Central Processing Unit). Also, the control unit 63 may be formed of a discrete product such as a transistor. The control unit 63 controls the resistance ratio between the first voltage dividing resistor 54 and the third voltage dividing resistor 56 based on the chromaticity control signal input from the host controller via the communication unit 61 .

The output unit 64 is electrically connected to the first voltage dividing resistor 54 and the third voltage dividing resistor 56 via a communication line, and outputs to the input terminal 505 a control signal indicating the switch 504 to be turned on. The control signal output from the output unit 64 indicates turning on any one of the plurality of switches 504 and turning off the other switches 504 .

(Action and effect of the light emitting device according to the third embodiment)
The light-emitting device 3 controls the resistance ratio between the first voltage-dividing resistor 54 and the third voltage-dividing resistor 56 based on the chromaticity control signal input from the host controller, thereby controlling the second light-emitting element group 12 And the ratio of the second current _I2 and the third current _I3 flowing through the third light emitting element group 13 can be changed.

FIG. 12 is a chromaticity diagram showing optical characteristics of light emitted from the light emitting device 3. As shown in FIG. In FIG. 12, curve L30 indicates the black body locus. A point P31 indicates the chromaticity of light emitted from the first light emitting element group 11, a point P32 indicates the chromaticity of light emitted from the second light emitting element group 12, and a point P33 indicates the chromaticity of light emitted from the thirteenth light emitting element group 13. Indicates the chromaticity of emitted light. A region R34 indicates an effective color gamut indicating the chromaticity of light that the light emitting device 3 can emit.

Although the effective color gamut of the light emitting device 3 is narrower than the light source color gamut formed by connecting the points P31, P32, and P33, it emits light having the desired chromaticity for the lighting device including the black body locus. can do.

(Structure and Function of Light Emitting Device According to Fourth Embodiment)
FIG. 13 is a circuit block diagram of a light emitting device according to the fourth embodiment.

The light emitting device 4 differs from the light emitting device 1 in that it does not have the reference voltage generation circuit 20 . Further, the light emitting device 4 differs from the light emitting device 1 in that it has a current sensor 55 , a first current control circuit 70 and a reference voltage generation circuit 75 . The configurations and functions of the components of the light-emitting device 4 other than the current sensor 55, the first current control circuit 70, and the reference voltage generation circuit 75 are the same as the configurations and functions of the components of the light-emitting device 1 denoted by the same reference numerals. Detailed description is omitted here.

The current sensor 55 is, for example, a current sensor such as a current detection amplifier, and is arranged between the first electrode 101 and the first light emitting element group 11, the second light emitting element group 12, and the third light emitting element group 13. The current sensor 55 detects the detected current I _D including the first current I ₁ , the second current I ₂ and the third current I ₃ flowing through the first light emitting element group 11 to the third light emitting element group 13, and the detected detection The current I _D is output to the reference voltage generating circuit 75 as corresponding voltage information.

The first current control circuit 70 has a first switch 71 , a first reference resistor 72 and a first comparator 73 . The first switch 71 is an nMOSFET, one end of which is the drain is connected to the first light emitting element group 11, the other end of the source is connected to one end of the first reference resistor 72, and the first switch 71 is the control terminal of the gate. It is connected to the output terminal of the comparator 73 . The other end of the first reference resistor 72 is grounded together with the other ends of the second detection resistor 32 and the third detection resistor 37 . A first input terminal of the first comparator 73 and first input terminals of the second comparator 33 and the third comparator 38 are each connected to the reference voltage generating circuit 75 . A second input terminal of the first comparator 73 is connected to one end of the first reference resistor 72 and receives the first detection voltage V _D1 that is the voltage across the first reference resistor 72 .

The reference voltage generation circuit 75 has an input section 76 , a storage section 77 , a control section 78 and an output section 79 . Any one of the first current I ₁ , the second current I ₂ and the third current I ₃ is selected so that the current values of the first current I ₁ , the second current I ₂ and the third current I ₃ have a predetermined ratio. Generates a reference voltage that is used to control one or two current values.

The input unit 76 is electrically connected to the current sensor 55 and receives a detected current signal indicating the detected current ID detected by the current sensor 55 .

The storage unit 77 includes semiconductor memory devices such as ROM and RAM, for example. The storage unit 77 stores an operating system program, a driver program, a control program, data, and the like used for processing in the control unit 78 .

The control unit 78 has one or more processors and their peripheral circuits, such as a CPU. Also, the control unit 78 may be formed by a transistor. _The controller 78 applies _a first reference _voltage V ₁ , to generate a second reference voltage _V2 and a third reference voltage _V3 .

The control unit 78 controls the first reference voltage so that the first current I ₁ , the second current I ₂ and the third current I ₃ flowing through the first to third light emitting element groups 11 to 13 have a predetermined ratio. V ₁ , a second reference voltage V ₂ and a third reference voltage V ₃ are generated. The control unit 78 controls the first current I ₁ , the second current I ₂ , and the third current I ₃ such that any one current value of the first current I 1 , the second current I 2 , and the third current I ₃ has a predetermined ratio to the other two current values. , to generate a reference voltage that controls any two current values of the second current _I2 and the third current _I3 . The control unit 78 applies a voltage equal to the power supply voltage Vdd, for example, to the first input terminals of the comparators corresponding to the light emitting element group through which the current controlled by the reference voltage does not flow, that is, the light emitting element group functioning as a master. It outputs a voltage that does not control the current flowing through the element group. In addition, a current having a predetermined ratio to the detection current ID is passed through the first input terminal of the comparator corresponding to the light emitting element group through which the current controlled by the reference voltage _flows , that is, the light emitting element group functioning as a slave. A reference voltage is output.

For example, when the current values of the second current _I2 and the third current _I3 are controlled and the current value of the first current _I1 is not controlled, the voltage equal to the power supply voltage Vdd is applied to the first input terminal of the first comparator 73. is entered. A second reference, in which the current values of the second current _I2 and the third current _I3 are in a predetermined ratio to the current value of the first current _I1 , are applied to the first input terminals of the second comparator 33 and the third comparator 38, respectively. A voltage _V2 and a third reference voltage _V3 are input.

When the current values of the first current _I1 and the third current _I3 are controlled and the current value of the second current _I2 is not controlled, the voltage equal to the power supply voltage Vdd is applied to the first input terminal of the second comparator 33. is entered. A first reference is applied to first input terminals of the first comparator 73 and the third comparator 38 so that the current values of the first current _I1 and the third current _I3 are a predetermined ratio to the current value of the second current _I2 . A voltage _V1 and a third reference voltage _V3 are input.

When the current values of the first current _I1 and the second current _I2 are controlled and the current value of the third current _I3 is not controlled, the voltage equal to the power supply voltage Vdd is applied to the first input terminal of the third comparator 38. is entered. A first reference is applied to the first input terminals of the first comparator 73 and the second comparator 33 so that the current values of the first current _I1 and the second current _I2 are in a predetermined ratio with respect to the current value of the third current _I3 . A voltage _V1 and a second reference voltage _V2 are input.

The output section 79 is electrically connected to the first input terminal of the first comparator 73 , the first input terminal of the second comparator 33 , and the first input terminal of the third comparator 38 , and the first input terminal generated by the control section 78 is electrically connected to the first input terminal of the third comparator 38 . It outputs a reference voltage V ₁ , a second reference voltage V ₂ and a third reference voltage V ₃ .

(Action and effect of the light emitting device according to the fourth embodiment)
The light emitting device 4 controls the first current control circuit 70, the second current control circuit ₃₀ and the third current control circuit ₃₅ with the first reference voltage _V1 , the second reference voltage V2 and the third reference voltage V3. , the first current _I.sub.1 , the second current _I.sub.2 and the third current _I.sub.3 can be controlled to have a predetermined ratio.

FIG. 14 is a chromaticity diagram showing changes in chromaticity of light emitted by the light emitting device 4 when the first reference voltage V ₁ , the second reference voltage V ₂ and the third reference voltage V ₃ are changed. In FIG. 14, the solid line indicates the range of light that can be emitted by the light emitting device 4, and the dashed line indicates the black body locus.

The light emitting device 4 generates a first current I ₁ and a second current I 1 flowing through the first to third light emitting element groups 11 to _{13 by the first reference voltage V 1 , second reference voltage V 2 and} third reference voltage V ₃ . The current _I2 and the third current _I3 can be controlled so that the chromaticity of the light emitted by the light emitting device 4 follows the blackbody locus.

(Structure and Function of Light Emitting Device According to Fifth Embodiment)
FIG. 15 is a circuit block diagram of a light emitting device according to the fifth embodiment.

The light emitting device 5 differs from the light emitting device 2 in that it has a reference voltage generation circuit 84 instead of the reference voltage generation circuit 40 . Further, the light emitting device 5 differs from the light emitting device 2 in that it further includes a current ratio control circuit 60 . The configurations and functions of the components of the light-emitting device 5 other than the reference voltage generation circuit 84 and the current ratio control circuit 60 are the same as the configurations and functions of the components of the light-emitting device 2 denoted by the same reference numerals. are omitted.

The light emitting device 5 includes a power supply circuit 10, a first light emitting element group 80, a second light emitting element group 81, a third light emitting element group 82, a fourth light emitting element group 83, a reference voltage generating circuit 84, It has a second current control circuit 30 , a third current control circuit 35 and a fourth current control circuit 89 . The light emitting device 5 further has a current ratio control circuit 60 , a first electrode 101 and a second electrode 102 .

The power supply circuit 10, the second current control circuit 30, the third current control circuit 35, the current ratio control circuit 60, the first electrode 101 and the second electrode 102 have already been described with reference to FIGS. A detailed description is omitted here.

The first light emitting element group 80 is formed by six serially connected first light emitting elements 80a. The first light emitting element 80a contains an LED die that emits blue light, a light conversion material such as a phosphor such as YAG that converts the blue light emitted from the LED die into yellow, and the LED die is sealed. It is a light-emitting element that has a sealing material that stops the light and emits white light.

The second light emitting element group 81 is formed by four serially connected second light emitting elements 81a. The second light emitting element 81a is a light emitting diode that emits light of the first color, which is blue.

The third light emitting element group 82 is formed by four serially connected third light emitting elements 82a. The third light emitting element 82a contains an LED die that emits blue light and a light conversion material such as a phosphor such as YAG that converts the blue light emitted from the LED die to green. It is a light-emitting element that has a sealing material that stops the light and emits green light.

The fourth light emitting element group 83 is formed by four serially connected fourth light emitting elements 83a. The fourth light emitting element 83a contains an LED die that emits blue light and a light conversion material such as a phosphor such as CASN that converts the blue light emitted from the LED die into red. It is a light-emitting element that has a sealing material that stops the light and emits red light.

The reference voltage generation circuit 84 is a voltage dividing circuit having a first detection resistor 85 , a second resistor pair 86 , a third resistor pair 87 and a fourth resistor pair 88 . Like the first detection resistor 21, the first detection resistor 85 is a resistor element having a resistance value of about several Ω, one end of which is connected to the first light emitting element group 80, and the other end of which is grounded. The second resistor pair 86 has a first voltage dividing resistor 86 a and a second voltage dividing resistor 86 b and generates a second reference voltage V ₂ that controls a second current I ₂ flowing through the second light emitting element group 81 . The third resistor pair 87 has a third voltage dividing resistor 87 a and a fourth voltage dividing resistor 87 b and generates a third reference voltage V ₃ that controls the third current I ₃ flowing through the third light emitting element group 82 . A fourth resistor pair 88 has a fifth voltage dividing resistor 88 a and a sixth voltage dividing resistor 88 b and generates a fourth reference voltage V ₄ that controls a fourth current I ₄ flowing through the fourth light emitting element group 83 .

The first voltage dividing resistor 86a and the fifth voltage dividing resistor 88a are variable resistors. The first voltage dividing resistor 86a and the fifth voltage dividing resistor 88a have structures similar to the first voltage dividing resistor 54 and the third voltage dividing resistor 56 described with reference to FIG. Description is omitted.

The fourth current control circuit 89 has a fourth switch 89a, a fourth detection resistor 89b, and a fourth comparator 89c, and has the same configuration as the second current control circuit 30 and the third current control circuit .

FIG. 16 is a chromaticity diagram showing optical characteristics of light emitted from the light emitting device 5. As shown in FIG. In FIG. 16, a thin curve L50 indicates the black body locus. A point P51 indicates the chromaticity of light emitted from the first light emitting element group 80, a point P52 indicates the chromaticity of light emitted from the second light emitting element group 81, and a point P53 indicates the chromaticity of light emitted from the 82nd light emitting element group 13. A point P54 indicates the chromaticity of light emitted from the fourth light emitting element group 83. FIG. A region R55 indicates an effective color gamut indicating the chromaticity of light that the light emitting device 5 can emit.

In the light emitting device 5, the first light emitting element group 80 with high luminous efficiency emits white light, and the second to fourth light emitting element groups 81 to 83 with lower luminous efficiency than the first light emitting element group 80 emit blue light. , emit green and red light, respectively. The light emitting device 5 emits white light from the first light emitting element group 80 having high luminous efficiency, and emits blue, green, and red light from the second light emitting element group 81 to the fourth light emitting element group 83 as complementary colors. As a result, the minimum color gamut can be achieved with a simple circuit configuration while maintaining high luminous efficiency.

Further, in the light emitting device 5, when the color of the light emitted from each of the first to fourth light emitting element groups 80 to 83 varies due to manufacturing variations, etc., the desired color and color temperature can be obtained. The current ratio control circuit 60 may be preset so that light is emitted. The light emitting device 5 can reduce the chromaticity tolerance by presetting the current ratio control circuit 60 so that light having a desired color and color temperature is emitted.

(Structure and Function of Light Emitting Device According to Sixth Embodiment)
FIG. 17 is a circuit block diagram of a light emitting device according to the sixth embodiment.

The light emitting device 6 includes a first light emitting element group 91, a second light emitting element group 92, a third light emitting element group 93, a first transistor 94, a second transistor 95, a third transistor 96, and a first switch. It has an element 97 , a second switching element 98 and a third switching element 99 . The light emitting device 6 further has a first electrode 101 and a second electrode 102 .

Each of the first light emitting element group 91 to the third light emitting element group 93 includes a plurality of LEDs connected in series. The LEDs included in the first light emitting element group 91 to the third light emitting element group 93 emit light of the same color such as blue. The LEDs included in the first light emitting element group 91 to the third light emitting element group 93 are, for example, a green phosphor that converts the blue light emitted by the LED into green and emits it, and a green phosphor that converts the blue light emitted by the LED into red. It is encapsulated with an encapsulant containing a red phosphor that converts and emits.

Each of the first transistor 94, the second transistor 95 and the third transistor 96 is an NPN bipolar transistor. The collector of the first transistor 94 is connected to the first light emitting element group 91, the collector of the second transistor 95 is connected to the second light emitting element group 92, and the collector of the third transistor 96 is connected to the third light emitting element group 93. be. The emitters of the first transistor 94, the second transistor 95 and the third transistor 96 are grounded.

One end of the first switching element 97 is connected to the base of the first transistor 94 and the other end of the first switching element 97 is connected to the collector of the first transistor 94 . One end and the other end of the first switching element 97 are open, and when the one end and the other end of the first switching element 97 are short-circuited by, for example, a solder jumper or wire bonding, the first switching element 97 is open. shorts between the base and collector of the first transistor 94 .

One end of the second switching element 98 is connected to the base of the second transistor 95 and the other end of the second switching element 98 is connected to the collector of the second transistor 95 . One end and the other end of the second switching element 98 are open, and when the one end and the other end of the second switching element 98 are shorted by, for example, a solder jumper and wire bonding, the second switching element 98 is open. shorts between the base and collector of the second transistor 95 .

One end of the third switching element 99 is connected to the base of the third transistor 96 and the other end of the third switching element 99 is connected to the collector of the third transistor 96 . A portion between one end and the other end of the third switching element 99 is open. shorts between the base and collector of the third transistor 96 .

When any one of first switching element 97, second switching element 98 and third switching element 99 is shorted, first transistor 94, second transistor 95 and third transistor 96 form a current mirror circuit. The first transistor 94, the second transistor 95, and the third transistor 96 form a current mirror circuit so that the first current I ₁ and the second current I flowing through the first light emitting element group 91 to the third light emitting element group 93 ₂ and the current value of the third current _I3 will be the same.

The switching elements to be short-circuited are determined according to the respective forward voltages of the first light emitting element group 91 to the third light emitting element group 93 . For example, the switching element connected to the light emitting element group having the highest threshold voltage for starting light emission among the first light emitting element group 91 to the third light emitting element group 93 may be short-circuited. By short-circuiting the switching element connected to the light emitting element group having the highest threshold voltage, a current matching the current flowing through the light emitting element group having the smallest current during light emission is generated from the first light emitting element group 91 to the second light emitting element group. The light can flow to all of the three light emitting element groups 93 . For example, when the threshold voltage at which the first light emitting element group 91 starts emitting light is higher than the threshold voltage at which the second light emitting element group 92 and the third light emitting element group 93 start emitting light, the first light emitting element group A first switching element 97 connected to 91 is shorted.

(Action and effect of the light emitting device according to the sixth embodiment)
By matching the current flowing through the first light emitting element group 91 to the third light emitting element group 93 at the time of light emission to the current flowing through the light emitting element group having the highest threshold voltage, the first light emitting element group 91 to the third light emitting element group The light emitted from 93 can be made uniform.

18(a) is a diagram showing an example of the light emitting state of a conventional light emitting device, and FIG. 18(b) is a diagram showing an example of the light emitting state of the light emitting device 6. FIG. The diagrams shown in FIGS. 18A and 18B are diagrams showing the light emission state when a low voltage is applied, such as when starting light emission.

In the conventional light emitting device shown in FIG. 18(a), the threshold voltage at which light emission is started differs for each light emitting element column, so only the light emitting element column with the low threshold voltage emits light. High light-emitting element columns do not emit light.

In the light-emitting device 6 shown in FIG. 18(b), the first light-emitting element group 91 to the third light-emitting element group 93 start emitting light simultaneously by the mirror circuit formed by the first transistor 94 to the third transistor 96. can be done.

(Modification of Light Emitting Device According to Embodiment)
The light emitting devices 1 to 4 each have a first light emitting element group 11 to a third light emitting element group 13 that respectively emit green, blue, and red light. It may have an element group. For example, the light-emitting device according to the embodiment may have two groups of light-emitting elements that emit light of warm color and light of cold color, respectively, and four light-emitting elements that emit light of green, blue, red, and amber. It may have groups.

Further, in the light-emitting devices 1 to 4, the reference voltage generation circuit and the current control circuit are connected to the cathode of the LED at the final stage of the light-emitting element group. may be connected to the anode of the LED in the first stage of the light emitting element group.

In the light emitting device 2, the first light emitting element group 11 emits green light, the second light emitting element group 12 emits blue light, and the third light emitting element group 13 emits red light. In the light emitting device according to the embodiment, the colors emitted by the first light emitting element group 11 to the third light emitting element group 13 are not limited. In the light emitting device according to the embodiment, the first light emitting element group 11 emits blue light, the second light emitting element group 12 emits red light, and the third light emitting element group 13 emits green light. good too. Alternatively, the first light emitting element group 11 may emit red light, the second light emitting element group 12 may emit green light, and the third light emitting element group 13 may emit blue light.

Further, in the light emitting devices 2 and 3, the first voltage dividing resistor 44 and the third voltage dividing resistor 46 and the first voltage dividing resistor 54 and the third voltage dividing resistor 56 are integrated, but the light emitting device according to the embodiment Then, the variable resistor included in the reference voltage generation circuit may be formed separately.

Further, in the light emitting device 3, the variable resistor and the resistance ratio control circuit are arranged as separate elements, but in the light emitting device according to the embodiment, the variable resistor and the resistance ratio control circuit are implemented as an integrated digital potentiometer or the like. may be integrated.

Further, in the light emitting device 4, the reference voltage generation circuit 75 controls any two current values of the first current I1 _, the second current _I2 and the third current _I3 in order to adjust the color of emitted light. Generates a reference voltage for However, in the light-emitting device according to the embodiment, when the plurality of light-emitting element columns emit light of the same color, the reference voltage generation circuit, like the light-emitting device 5, according to the forward voltage of the plurality of light-emitting element groups, A group of light emitting elements for controlling the current value may be determined.

In the light emitting device according to the embodiment, the reference voltage generating circuit does not control the current value of the current flowing through the light emitting element group with the highest forward voltage, but controls the current value of the current flowing through the other light emitting element groups. In the reference voltage generation circuit, a current control circuit arranged corresponding to a light emitting element group that controls the current value of the current flowing through the light emitting element array that controls the current value of the current flowing through the light emitting element group with the lowest current. Generate a reference voltage to match the current value of

Further, the light emitting device 6 has the first to third light emitting element groups 91 to 93, but the light emitting device according to the embodiment may have two or four or more light emitting element groups. Further, in the light emitting device according to the embodiment, the first transistor 94 to third transistor 96 and the first switching element 97 to third switching element 99 are the first stage LEDs of the first light emitting element group 91 to third light emitting element group 93. may be connected to the anode of

Further, in the light emitting device 6, the first switching element 97 to the third switching element 99 are formed so as to short-circuit the bases and collectors of the first to third transistors 94 to 96, respectively. However, in the light emitting device according to the embodiment, the plurality of switching elements may be formed such that the bases and collectors of the plurality of transistors can be opened. The plurality of switching elements are released between the respective bases and collectors of the plurality of transistors by, for example, cutting the wiring pattern forming the plurality of switching elements with a wiring pattern cutting device such as a laser irradiation device.

Claims (15)

a pair of electrode pairs;
a first light emitting element group that emits light when current is supplied from the pair of electrodes;
a second light emitting element group that is connected in parallel to the first light emitting element group and that emits light when current is supplied from the pair of electrodes;
The current values of the first current and the second current are such that the current value of the first current flowing through the first light emitting element group and the current value of the second current flowing through the second light emitting element group have a predetermined ratio. a reference voltage generation circuit for generating a reference voltage used to control one of the
a current control circuit that controls one of the first current and the second current and does not control the other of the first current and the second current based on the reference voltage;
A light-emitting device comprising: The reference voltage includes a second reference voltage used to control the current value of the second current;
The current control circuit controls the second current based on the second reference voltage so that the current value of the second current has a predetermined ratio with respect to the current value of the first current. 3. A light emitting device according to claim 1, comprising a current control circuit. The first light emitting element group emits light of a first color,
3. The light emitting device according to claim 2, wherein said second light emitting element group emits light of a second color different from said first color. A third light-emitting element group connected in parallel to the first light-emitting element group and the second light-emitting element group, and different from the first color and the second color when a current is supplied from the pair of electrodes. a third light emitting element group that emits colored light;
a third current control circuit for controlling the third current so that the current value of the third current flowing through the third light emitting element group has a predetermined ratio with respect to the current value of the first current; death,
4. The light emitting device of claim 3, wherein said reference voltages further comprise a third reference voltage used to control the current value of said third current. The reference voltage generation circuit has a second resistor pair connected in series with the first light emitting element group, and generates the second current using a divided voltage divided by the second resistor pair as the second reference voltage. 5. The light-emitting device according to claim 4, outputting to a control circuit. 6. The light emitting device according to claim 5, wherein one resistor included in said second resistor pair is a variable resistor. The second current control circuit is
a second switch having one end connected to the final stage light emitting element of the second light emitting element group;
a second detection resistor having one end connected to the other end of the second switch;
The input second reference voltage is compared with the second detection voltage applied to the second detection resistor, and the second switch is operated so that the second reference voltage matches the second detection voltage. a second comparator that controls
The light emitting device according to claim 5 or 6, comprising: The reference voltage generation circuit further includes a third resistance pair connected in parallel to the second resistance pair, and uses the divided voltage divided by the third resistance pair as the third reference voltage to generate the third current. 8. The light-emitting device according to claim 5, which outputs to a control circuit. 9. The light emitting device according to claim 8, wherein one resistor included in said third resistor pair is a variable resistor. When the first light emitting element group, the second light emitting element group, and the third light emitting element group are connected in parallel and current is supplied from the pair of electrodes, the first color and the second color and a fourth light emitting element group that emits light of a fourth color different from any of the third colors;
a fourth current control circuit for controlling the third current so that the current value of the fourth current flowing through the fourth light emitting element group has a predetermined ratio with respect to the current value of the first current; death,
The reference voltage further includes a fourth reference voltage used to control the current value of the fourth current;
5. The light emitting device of Claim 4, wherein the first color light is white. The current control circuit is
a first current control circuit capable of controlling the first current such that the current value of the first current has a predetermined ratio to the current value of the second current;
a second current control circuit capable of controlling the second current such that the current value of the second current has a predetermined ratio to the current value of the first current;
The reference voltage generation circuit adjusts the reference voltage so that the current value of one of the first current and the second current has a predetermined ratio with respect to the current value of the other of the first current and the second current. 11. The light emitting device of Claim 1, which generates a voltage. The first light emitting element group emits light of a first color,
12. The light emitting device according to claim 11, wherein said second light emitting element group emits light of a second color different from said first color. The forward voltage of one of the first light emitting element group and the second light emitting element group whose current value is controlled is higher than the forward voltage of the other of the first light emitting element group and the second light emitting element group whose current value is not controlled. is also low,
12. The light emitting device according to claim 11, wherein said reference voltage generation circuit generates said reference voltage such that current values of said first current and said second current are desired values. The reference voltage generation circuit has a second resistance pair connected in series with the first light emitting element group and a third resistance pair connected in parallel with the second resistance pair,
One resistance of each of the second resistance pair and the third resistance pair includes a first contact connected to the other of the second resistance pair, a second contact connected to the other of the third resistance pair, and the integrated by a resistor arranged between the first contact and the second contact, a movable contact connectable to any position of the resistor, and a third contact connected to the movable contact; Item 5. The light-emitting device according to item 4. an operating member formed with an internal gear;
a rotary member having a cylindrical shaft, a first gear disposed at one end of the shaft and screwed with the internal gear, and a second gear disposed at one end of the shaft;
A third gear screwed to the second gear is provided, and according to the rotation of the third gear, the ratio of the current flowing through the second light emitting element group and the ratio of the current flowing through the third light emitting element group a current adjustment unit that adjusts the
a light emitting device according to claim 14;
When the third gear rotates in response to the rotation of the operating member in the first direction, the movable contact reduces the resistance between the first contact and the movable contact and moves the second contact. move so as to increase the resistance between the movable contacts ;
When the third gear rotates in response to rotation of the operating member in a second direction opposite to the first direction, the movable contact increases resistance between the first contact and the movable contact. and moves such that the resistance between the second contact and the movable contact decreases.

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