JP2012256545A - Light source driving device, light source device, projector, and controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To materialize a light source driving device capable of carrying out both of color light-emitting and white light-emitting while suppressing a manufacturing cost thereof.SOLUTION: A driving device 10 includes a current supply portion 15 capable of supplying a current to LEDs 100, 200, and 300; a resistance 13 and a resistance 14 respectively connected to the LEDs 100 and 200; a swith portion 11 selectively connecting and disconnecting the current supply portion 15 to any one of the plurality of the LEDs without using the resistance 13 and the resistance 14 therebetween; and a switch portion 12 connecting or disconnecting the current supply portion 15 to each LED to which the resistances are connected, through the resistances. In a first light-emitting mode, any one of the plurality of the LEDs is connected to the current supply portion 15 by the switch portion 11. In a second light-emitting mode, the switch portion 12 is set in a connecting state, and the LED to which the resistances are not connected are connected to the current supply portion 15 by the switch portion 11.

Description

  The present invention relates to a light source driving device for driving a light source. The present invention also relates to a light source device including a light source and a light source driving device, and a projector including such a light source device. The present invention also relates to a method for controlling the light source driving device.

  In recent years, LED projectors, which are projectors using light emitting diodes (LEDs) as light sources, have been developed. The LED has a small amount of heat generation and a long life compared with a high-pressure mercury lamp conventionally used as a light source for a projector. In addition, since the LED is small and consumes little power, a small palm-sized projector (also called a pico projector) that can fit into a pocket has been realized.

  As a light source of such an LED projector, an LED that emits red light (also expressed as red LED or LED (R)), an LED that emits green light (also expressed as green LED or LED (G)), An LED that emits blue light (also referred to as a blue LED or LED (B)) and an LED that emits white light (also referred to as a white LED or LED (W)) are often used in combination. However, since white LED is expensive, it was a factor of cost increase. Therefore, a light source driving device capable of emitting white light without providing a white LED has been proposed.

  FIG. 5 is a diagram showing a configuration of a conventional light source driving device (denoted as driving device 40) capable of emitting white light without providing a white LED. As shown in FIG. 5, the driving device 40 includes current supply units 41, 42, and 43 for individually supplying current to the LED (R) 100, the LED (G) 200, and the LED (B) 300. It has. Here, the current supply units 41, 42, and 43 can adjust the current value supplied to the LEDs in accordance with the setting signals # 44 a, # 44 b, and # 44 c supplied from the control unit 44.

  Since the drive device 40 shown in FIG. 5 can simultaneously control the value of the current supplied to each LED, it can emit white light. Further, since each LED can emit light at different timings, time-division color light emission (field sequential light emission) can also be performed. FIG. 6 shows a correspondence relationship between each emission color and the on / off state of the current supply units 41, 42, and 43.

  However, since the drive device 40 shown in FIG. 5 is configured to include a current supply unit for each LED, there is a problem that the cost increases due to an increase in the number of components. Moreover, since the calorific value of the whole drive device becomes large and a heat dissipation measure is required, there is a problem that miniaturization is difficult.

  As an attempt to reduce the number of current supply units, for example, there is a configuration including one current supply unit for three LEDs of a red LED, a green LED, and a blue LED as described in Patent Document 1. Can be mentioned. FIG. 7 is a diagram schematically illustrating a configuration of a light source driving device (described as a driving device 50) described in Patent Document 1. As shown in FIG. 7, the driving device 50 includes one current supply unit 52 and a switch unit 51. The switch unit 51 switches the LED connected to the current supply unit 53 according to the setting signal # 53b supplied from the control unit 53.

  As illustrated in FIG. 8, the driving device 50 illustrated in FIG. 7 can selectively emit each of the red LED, the green LED, and the blue LED by switching the switch unit 51. Therefore, time-division color emission is possible by causing the red LED, the green LED, and the blue LED to emit light at different timings. Furthermore, since there is one current supply unit, cost and heat generation can be reduced.

JP 2009-141864 A (publication date: June 25, 2009)

  However, the driving device 50 shown in FIG. 7 cannot emit white light because the LEDs cannot emit light simultaneously. For this reason, in order to perform white light emission, a separate white LED is required, leading to a problem that the manufacturing cost increases.

  The present invention has been made in view of the above-described problems, and an object thereof is to realize a light source driving device capable of performing both color light emission and white light emission while suppressing manufacturing cost.

  In order to solve the above problems, a light source driving device according to the present invention is a light source driving device that drives a plurality of light sources that individually emit light of each color, and is a current that can supply current to the plurality of light sources. A supply unit, a resistance unit individually connected to at least one of the plurality of light sources, and the current supply unit are selectively selected with respect to any one of the plurality of light sources without passing through the resistance unit. A first switch unit that connects or disconnects to the light source, a second switch unit that connects or disconnects the current supply unit to each light source to which the resistor unit is connected via the resistor unit, and the current A control unit that controls the supply unit, the first switch unit, and the second switch unit, and the control unit shuts off the second switch unit in the first light emission mode. And the plurality of light sources Any one is connected to the current supply unit by the first switch unit, and in the second light emission mode, the second switch unit is set to a connected state, and the light source to which the resistor unit is not connected Is connected to the current supply unit by the first switch unit.

  According to the light source driving device configured as described above, a current supply unit capable of supplying current to the plurality of light sources, a resistance unit individually connected to at least one of the plurality of light sources, and the above A first switch unit that selectively connects or disconnects a current supply unit to any one of the plurality of light sources without passing through the resistor unit, and the current supply unit is connected to the resistor unit. A second switch unit that is connected to or disconnected from each light source via the resistor unit, and a control unit that controls the current supply unit, the first switch unit, and the second switch unit. In the first light emission mode, the control unit sets the second switch unit to a cut-off state, and the control unit controls any one of the plurality of light sources by the first switch unit. Connect to the current supply.

  Therefore, according to the light source driving device, in the first light emission mode, it is possible to perform color light emission that causes any one of the light sources of each color to emit light.

  In the second light emission mode, the control unit sets the second switch unit to a connected state, and a light source not connected to the resistor unit is connected to the current supply unit by the first switch unit. Connecting. Accordingly, in the second light emission mode, the current supply unit supplies current through the resistance unit to the light source to which the resistance unit is connected among the light sources of each color, and the light source of each color. Among them, a current is supplied to the light source to which the resistance unit is not connected without passing through the resistance unit.

  Therefore, according to the light source driving device, by adjusting the resistance value of the resistance unit, it is possible to make the color mixture of each color emitted by each light source have a desired color in the second light emission mode. . For example, when each light source emits three primary colors individually, in the second light emission mode, the color mixture of each color emitted by each light source can be white.

  In addition, the light source driving device only needs to include a current supply unit common to each light source, and it is not necessary to individually provide a current supply unit for each light source, so that the manufacturing cost is suppressed.

  Thus, according to the light source driving device, it is possible to perform both color light emission and white light emission while suppressing the manufacturing cost.

  In the light source driving device, it is preferable that the resistance unit is individually connected to a light source other than the light source having the highest operating voltage among the plurality of light sources.

  According to the above configuration, since the resistance unit is individually connected to a light source other than the light source having the highest operating voltage among the plurality of light sources, the current supply is performed in the second light emission mode. The unit supplies a current to the light source having the highest operating voltage without passing through the resistor unit, and supplies a current to each other light source through the resistor unit.

  Therefore, according to the above configuration, the value of the current supplied to the light source other than the light source having the highest operating voltage is made smaller than the value of the current supplied to the light source having the highest operating voltage. Can do.

  Thereby, it is possible to prevent an excessive current from being supplied to a light source having a relatively low operating voltage, and to further prevent the light source having a relatively low operating voltage from being damaged. Play.

  In the light source driving device, it is preferable that the control unit controls on / off of the first and second switch units and a current value of a current supplied by the current supply unit in synchronization.

  According to the above configuration, the control unit controls the on / off of the first and second switch units and the current value of the current supplied by the current supply unit in synchronization, so the first light emission Each light source can appropriately emit light in both the mode and the second light emission mode. For example, the first switch unit controls the value of the current supplied by the current supply unit according to which of the light sources the current supply unit is connected to. Can be emitted.

  In the light source driving device, it is preferable that the resistance portion is constituted by a resistor having a predetermined resistance value.

  According to said structure, since the said resistance part is comprised from the resistor which has a predetermined resistance value, it can perform both color light emission and white light emission by simple structure.

  In addition, what is necessary is just to use the thing according to the characteristic of the light source to which the said resistance part is connected as said predetermined | prescribed resistance value. For example, a resistor having a larger resistance value may be used as a resistor connected to a light source having a lower operating voltage.

  In the light source driving device, it is preferable that the resistance unit is composed of a variable resistor whose resistance value can be controlled.

  According to said structure, since the said resistance part is comprised from the variable resistance which can control resistance value, the resistance value of each resistance part can be changed easily.

  In the light source driving device, it is preferable that the resistor section includes a transistor capable of controlling a current flowing through the light source.

  According to said structure, the electric current which flows into the said light source can be controlled easily.

  A light source device according to the present invention includes the light source driving device and a plurality of light sources that individually emit light of each color, and the light source driving device drives the plurality of light sources.

  According to the light source device configured as described above, the same effects as those of the light source driving device can be obtained.

  In the light source device, it is preferable that the number of the light sources is 3, and each light source emits three primary colors individually.

  According to the above configuration, any one of the three primary colors can be appropriately emitted in the first emission mode, and a desired mixed color of the three primary colors can be emitted in the second emission mode. . For example, white light can be emitted as a mixed color of three primary colors.

  In the light source device, the three primary colors are preferably red, green, and blue.

  According to the above configuration, any one of red, green, and blue can be appropriately emitted in the first emission mode, and desired red, green, and blue in the second emission mode. Can be emitted. For example, white light can be emitted as a mixed color of three primary colors.

  In the light source device, each of the plurality of light sources is preferably a light emitting diode.

  According to said structure, since the said light source is a light emitting diode, there exists the further effect that the light-emitting device with little calorific value and a long lifetime can be implement | achieved.

  A projector including the light source device is also included in the scope of the present invention.

  Further, the control method according to the present invention includes a current supply unit capable of supplying a current to a plurality of light sources that individually emit light of each color, a resistance unit individually connected to at least one of the plurality of light sources, A first switch unit that selectively connects or disconnects the current supply unit to any one of the plurality of light sources without passing through the resistor unit, and the current supply unit is connected to the resistor unit. A control method of a light source driving device comprising: a second switch unit that connects or disconnects to each connected light source via the resistor unit. Is set to a cut-off state, and any one of the plurality of light sources is connected to the current supply unit by the first switch unit, and in the second light emission mode, the second switch unit is Set the connection state, The light source whose serial resistor portion is not connected is connected to the current supply section by the first switch portion is characterized in that.

  According to the control method, in the first light emission mode, the second switch unit is set to a cut-off state, and any one of the plurality of light sources is connected to the current supply unit by the first switch unit. Connecting. Therefore, in the first light emission mode, it is possible to perform color light emission in which any one of the light sources of each color emits light.

  In the second light emission mode, the second switch unit is set to a connected state, and a light source to which the resistor unit is not connected is connected to the current supply unit by the first switch unit. Accordingly, in the second light emission mode, the current supply unit supplies current through the resistance unit to the light source to which the resistance unit is connected among the light sources of each color, and the light source of each color. Among them, a current is supplied to the light source to which the resistance unit is not connected without passing through the resistance unit.

  Therefore, according to the above control method, the color mixture of each color emitted by each light source can be set to a desired color. For example, when each light source emits three primary colors individually, in the second light emission mode, the color mixture of each color emitted by each light source can be white.

  In addition, the light source driving device described above only needs to include a current supply unit common to each light source, and it is not necessary to individually provide a current supply unit for each light source, so that the manufacturing cost is suppressed.

  Thus, according to the control method of the light source driving device, both color light emission and white light emission can be performed while suppressing the manufacturing cost.

  As described above, the light source driving device according to the present invention is a light source driving device that drives a plurality of light sources that individually emit light of each color, and a current supply unit that can supply current to the plurality of light sources, The resistance unit individually connected to at least one of the plurality of light sources and the current supply unit are selectively connected to or disconnected from any one of the plurality of light sources without passing through the resistance unit. A first switch unit, a second switch unit for connecting or blocking the current supply unit to or from each light source to which the resistor unit is connected via the resistor unit, the current supply unit, And a control unit that controls the second switch unit, and the control unit sets the second switch unit to a cut-off state in the first light emission mode. , Any one of the plurality of light sources The first switch unit is connected to the current supply unit, and in the second light emission mode, the second switch unit is set to a connected state, and the light source not connected to the resistor unit is connected to the first light source. The switch unit is connected to the current supply unit.

  According to the light source driving device configured as described above, it is possible to perform both color light emission and white light emission while suppressing manufacturing costs.

It is a figure which shows the structure of the light source device which concerns on the 1st Embodiment of this invention. It is a table | surface for demonstrating operation | movement of the light source device which concerns on the 1st Embodiment of this invention, Comprising: (a) is the correspondence of the luminescent color in a 1st light emission mode, and the connection aspect by two switch parts. (B) shows the correspondence between the emission color in the second emission mode and the connection mode by the two switch units. It is a figure which shows the structure of the light source device which concerns on the 2nd Embodiment of this invention. It is a figure which shows the structure of the light source device which concerns on the 3rd Embodiment of this invention. It is a figure which shows typically the structure of the light source device which concerns on a prior art. 6 is a table showing a correspondence relationship between light emission colors emitted by the light source device shown in FIG. 5 and ON / OFF of three current supply units. It is a figure which shows typically the other light source device which concerns on a prior art. It is a table | surface which shows the correspondence of the luminescent color which the light source device shown in FIG. 7 light-emits, and the connection aspect of a switch part.

Embodiment 1
(Light source device 1)
An embodiment according to the present invention will be described with reference to FIG.

  FIG. 1 is a diagram illustrating a configuration of a light source device 1 according to the present embodiment. As shown in FIG. 1, the light source device 1 includes an LED (R) 100, an LED (G) 200, an LED (B) 300, and a driving device (light source driving device) 10. The driving device 10 is configured to drive the LED (R) 100, the LED (G) 200, and the LED (B) 300, and as shown in FIG. 1, the switch unit 11 (first switch unit) and A switch unit 12 (second switch unit), resistors 13 and 14, a current supply unit 15 and a control unit 16 are provided.

  The LED (R) 100, the LED (G) 200, and the LED (B) 300 emit red, green, and blue light, respectively, by the current supplied from the driving device 10. As shown in FIG. 1, the anodes of the LED (R) 100, the LED (G) 200, and the LED (B) 300 are connected to a current supply unit 15 described later. Further, the cathodes of the LED (R) 100, the LED (G) 200, and the LED (B) 300 are connected to the contacts a, b, and c included in the switch unit 11, respectively.

  Note that the operating voltage of each LED when the current value flowing through each LED is 700 (mA) is, for example, as shown below.

LED (R) 100: 2.35 (V)
LED (G) 200: 3.48 (V)
LED (B) 300: 3.52 (V)
The operating voltage is a voltage value to be applied in order to pass a predetermined current to each LED.

  Below, it demonstrates as a thing with the highest operating voltage of LED (B) among LED (R) 100, LED (G) 200, and LED (B) 300, but this limits this embodiment. is not.

  The resistor 13 has one end connected to the cathode side of the LED (R) 100 and the other end connected to the contact d of the switch unit 12. The resistor 14 has one end connected to the cathode side of the LED (G) 200 and the other end connected to the contact e of the switch unit 12. On the other hand, as shown in FIG. 1, no resistor is connected to the LED (B) 300.

  The specific resistance values of the resistor 13 and the resistor 14 can be adjusted in advance so that the color mixture of the light emitted from each LED that emits light in the second light emission mode described later is white.

  The current supply unit 15 is configured to supply current (more specifically, forward current) to the LED (R) 100, LED (G) 200, and LED (B) 300, and is supplied from the control unit 16. The value of the voltage applied to these LEDs and the value of the current supplied to these LEDs can be changed according to the setting signal # 16a.

  The control part 16 is a structure for controlling each part with which the drive apparatus 10 is provided, supplies setting signal # 16a to the electric current supply part 15, supplies setting signal # 16b to the switch part 11, and switches The setting signal # 16c is supplied to the unit 12. The control unit 16 can control the value of the current supplied from the current supply unit 15 to each LED and the on / off operation of the switch unit 11 and the switch unit 12 in synchronization with these setting signals.

  Note that the specific waveforms of the setting signals # 16a, # 16b, and # 16c are not limited to the present embodiment, but as these setting signals, for example, signals having a rectangular waveform can be used.

  The switch unit 11 includes an end x connected to the current supply unit 15 and three contacts (contacts a, b, and c) that can selectively connect the end. The switch unit 11 exclusively connects or disconnects the current supply unit 15 to each contact in accordance with the setting signal # 16b supplied from the control unit 16. In other words, the switch unit 11 selectively connects the current supply unit 15 to any one of the contacts a, b, and c in accordance with the setting signal # 16b supplied from the control unit 16. .

  More specifically, when the end x included in the switch unit 11 is connected to the contact a, a current flows through the LED (R) 100 and the LED (R) 100 emits light. Similarly, when the end x is connected to the contact b, a current flows through the LED (G) 200, and the LED (G) 200 emits light. Further, when the end x is connected to the contact c, a current flows through the LED (B) 300, and the LED (B) 300 emits light.

  The switch unit 12 includes an end y connected to the current supply unit 15 and two contacts (contacts d and e) that can connect the end y simultaneously. The switch unit 12 connects or disconnects the contacts d and e and the current supply unit 15 according to the setting signal # 16c supplied from the control unit 16.

  As will be described below, the driving device 10 can cause each LED to emit light in any one of the first light emission mode and the second light emission mode.

(First emission mode)
In the first light emission mode, the driving device 10 causes the LED (R) 100, the LED (G) 200, and the LED (B) 300 to emit light at different timings. That is, the first light emission mode is a mode in which any one of LED (R) 100, LED (G) 200, and LED (B) 300 emits light at each time (time division light emission mode).

  FIG. 2A shows the relationship between the emission color (red, green, blue) in the first emission mode and the connection mode of the switch unit 11 and the switch unit 12.

  As shown in FIG. 2A, in the first light emission mode, the end x included in the switch unit 11 is connected to one of the contacts a, b, and c according to the setting signal # 16b. Further, in the first light emission mode, the switch unit 12 remains off.

  Thus, in the first light emission mode, at any one time, any one of the LED (R) 100, the LED (G) 200, and the LED (B) 300 emits light.

(Second flash mode)
The driving device 10 causes the LED (R) 100, the LED (G) 200, and the LED (B) 300 to emit light simultaneously in the second light emission mode. The second light emission mode is a mode in which white light is emitted by causing three LEDs, LED (R) 100, LED (G) 200, and LED (B) 300, to emit light simultaneously.

  FIG. 2B shows the relationship between the emission color (white) in the second emission mode and the connection mode of the switch unit 11 and the switch unit 12.

  As shown in FIG. 2B, in the second light emission mode, the end x of the switch unit 11 is connected to the contact c. Thereby, an electric current flows into LED (B) 300 and LED (B) 300 light-emits blue.

  Further, as shown in FIG. 2B, the end portion y of the switch portion 12 is connected to the contacts d and e. Thereby, an electric current flows into LED (R) 100 and LED (G) 200, and LED (R) 100 and LED (G) 200 light-emit in red and green, respectively.

  In general, the LED (R) 100, the LED (G) 200, and the LED (B) 300 have different operating voltages. Therefore, even if the same voltage is applied to these LEDs, the light emitted from these LEDs is emitted. The color mixture is not always white. Even if the same voltage is applied to each LED, a large current does not flow in an LED having a high operating voltage, but an overcurrent may flow in an LED having a low operating voltage.

  The drive device 10 according to the present embodiment is an LED (R) that is an LED other than the LED (B) 300 having the highest operating voltage among the LED (R) 100, the LED (G) 200, and the LED (B) 300. Since the resistor 13 and the resistor 14 connected to the LED 100 and the LED (G) 200 are provided, it is possible to prevent an overcurrent from being supplied to the LED (R) 100 and the LED (G) 200. . Further, by adjusting the resistance values of the resistor 13 and the resistor 14 in advance, the color mixture of light emitted from each LED can be white.

(Effects produced by the driving device 10)
As described above, the driving device 10 time-divides each LED by a simple configuration including one current supply unit for the LED (R) 100, the LED (G) 200, and the LED (B) 300. It is possible to realize both the first light emission mode in which light is emitted and the second light emission mode in which white light is emitted by causing each LED to emit light simultaneously.

(Additional notes regarding the first embodiment)
In the above description, the configuration in which the resistor 13 and the resistor 14 are connected to the LED (R) 100 and the LED (G) 200 has been described as an example, but this does not limit the present embodiment. More generally, the resistor 13 and the resistor 14 may be connected to an LED other than the LED having the highest operating voltage among the LED (R) 100, the LED (G) 200, and the LED (B) 300. .

  In the above description, the configuration in which the resistor 13 and the resistor 14 are connected to the cathode side of the LED (R) 100 and the LED (G) 200 is taken as an example, but the present embodiment is limited to this. Instead, the resistor 13 and the resistor 14 may be connected to the anode side of the LED (R) 100 and the LED (G) 200.

  In the above description, the drive device 10 has been described with an example of a configuration including the two resistors 13 and 14. However, the present embodiment is not limited to this. In general, the operating voltage of each LED can vary depending on the material constituting the LED, the size of the chip on which the LED is mounted, and the like. Depending on the material and chip size, either one of the resistor 13 and the resistor 14 can be omitted.

[Embodiment 2]
A second embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the part similar to the part already demonstrated in Embodiment 1, and the description is abbreviate | omitted.

(Light source device 2)
As illustrated in FIG. 3, the light source device 2 according to the present embodiment includes variable resistors (resistor portions) 21 and 22, respectively, instead of the resistors (resistor portions) 13 and 14 included in the light source device 1. Here, the resistance values of the variable resistors 21 and 22 can be set in a range from 0 to 200 ohms, for example. The specific resistance values of the variable resistors 21 and 22 can be individually changed by a setting signal # 23d supplied from the control unit 23.

  The control unit 23 is configured to control each unit included in the driving device (light source driving device) 20, supplies the setting signal # 23 a to the current supply unit 15, and sets the setting signal # 23 b to the switch unit 11. , The setting signal # 23c is supplied to the switch unit 12, and the setting signal # 23d is supplied to the variable resistors 21 and 22. The control unit 23 can control the value of the current supplied from the current supply unit 15 to each LED and the on / off operation of the switch unit 11 and the switch unit 12 in synchronization with these setting signals.

  The specific waveforms of the setting signals # 23a, # 23b, and # 23c are not limited to the present embodiment, but as these setting signals, for example, signals having rectangular waveforms can be used.

  Also in the driving device 20, as in the first embodiment, the LED can emit light in any one of the first light emission mode and the second light emission mode. Since details of these light emission modes have already been described in the first embodiment, description thereof is omitted here, and a method of adjusting the resistance values of the variable resistors 21 and 22 will be described below.

(Adjustment method for variable resistance)
The resistance values of the variable resistors 21 and 22 are preferably adjusted by the following steps.

(Step S101)
First, the resistance values of the variable resistors 21 and 22 are set higher than the value assumed as the final resistance value.

(Step S102)
Subsequently, the value of the drive voltage supplied by the current supply unit 15 is adjusted so that the brightness of the light emitted from the LED (B) 300 becomes a predetermined brightness.

(Step S103)
Subsequently, the resistance values of the variable resistors 21 and 22 are lowered and adjusted so that the color mixture of the light emitted from the LED (R) 100, the LED (G) 200, and the LED (B) 300 is white. In this state, the current value of the current flowing through each LED is the optimum value when white light is emitted.

(Effects produced by the driving device 20)
In addition to the effect which the drive device 10 which concerns on Embodiment 1 show | plays, the drive device 20 has the following effects.

  Since the drive device 20 includes the variable resistors 21 and 22, it is easy to adjust the balance of each color when white light is emitted in the second light emission mode. In general, the luminous efficiency of an LED has temperature dependence. However, according to the driving device 20, by changing the resistance values of the variable resistors 21 and 22 according to the temperature, a white color can be obtained even if the temperature changes. It can be adjusted not to change.

  Moreover, since the light emission efficiency of each LED generally has individual dependence, when the LED to be used is replaced, the white color may change. According to the drive device 20, even in such a case, the white color can be kept constant by adjusting the resistance values of the variable resistors 21 and 22.

(Additional notes regarding Embodiment 2)
In the above description, the configuration in which the variable resistor 21 and the variable resistor 22 are connected to the LED (R) 100 and the LED (G) 200 has been described as an example, but this does not limit the present embodiment. More generally, the variable resistor 21 and the variable resistor 22 are connected to LEDs other than the LED having the highest operating voltage among the LED (R) 100, the LED (G) 200, and the LED (B) 300. That's fine.

  In the above description, the variable resistor 21 and the variable resistor 22 are exemplified as a configuration in which the LED (R) 100 and the LED (G) 200 are connected to the cathode side. However, the present embodiment is not limited thereto. Instead, the variable resistor 21 and the variable resistor 22 may be connected to the anode side of the LED (R) 100 and the LED (G) 200.

  In the above description, the driving device 20 has been described as an example in which the variable resistance 21 and the variable resistance 22 are provided with two variable resistors. However, the present embodiment is not limited to this. In general, the operating voltage of each LED can vary depending on the material constituting the LED, the size of the chip on which the LED is mounted, and the like. Depending on these materials and the chip size, one of the variable resistor 21 and the variable resistor 22 can be omitted.

[Embodiment 3]
(Light source device 3)
Another embodiment according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected about the part similar to the part already demonstrated in Embodiment 1, and the description is abbreviate | omitted.

  As shown in FIG. 4, the light source device 3 according to the present embodiment includes a transistor 31, a resistor 33, a resistor 34, and a power source 37 instead of the resistor (resistor unit) 13 included in the light source device 1. Similarly, the light source device 3 includes a transistor 32, a resistor 35, a resistor 36, and a power source 38 instead of the resistor 14 included in the light source device 1.

  The transistor 31, the resistor 33, the resistor 34, and the power source 37 are configured to adjust the value of the current flowing through the LED (R) 100, and the transistor 32, the resistor 35, the resistor 36, and the power source 38 are configured by the LED (G This is a configuration for adjusting the value of the current flowing through 200.

  As shown in FIG. 4, the collector of the transistor 31 is connected to the cathode side of the LED (R) 100, and the emitter of the transistor 31 is connected to the contact point d of the switch unit 21. The base of the transistor 31 is connected to the power source 37 via the resistor 33. The resistor 34 is connected between the base and emitter of the transistor 31.

  As shown in FIG. 4, the collector of the transistor 32 is connected to the cathode side of the LED (G) 200, and the emitter of the transistor 32 is connected to the contact e of the switch unit 21. The base of the transistor 32 is connected to the power source 38 via the resistor 35. The resistor 36 is connected between the base and emitter of the transistor 31.

  The power source 37 and the power source 38 are individually controlled by the setting signal # 39d and supply the base currents of the transistor 31 and the transistor 32, respectively. Since the collector-emitter currents of the transistors 31 and 32 vary depending on the respective base currents, the currents that flow through the LED (R) 100 and the LED (G) 200 by controlling the power supply 37 and the power supply 38. The value of can be adjusted.

  As described above, the transistor 31, the resistor 33, the resistor 34, and the power source 37 as a whole can also be expressed as a configuration corresponding to the variable resistor 21 according to the second embodiment. Hereinafter, the transistor 31, the resistor 33, the resistor 34, and the power source 37 may be collectively referred to as a resistor portion R1. Further, the transistor 32, the resistor 35, the resistor 36, and the power source 38 can be expressed as a configuration corresponding to the variable resistor 22 according to the second embodiment as a whole. Hereinafter, the transistor 32, the resistor 35, the resistor 36, and the power source 38 may be collectively referred to as a low rear portion R2.

  The control unit 39 is configured to control each unit included in the driving device (light source driving device) 30, supplies the setting signal # 39 a to the current supply unit 15, and sets the setting signal # 39 b to the switch unit 11. , The setting signal # 39c is supplied to the switch unit 12, and the setting signal # 39d is supplied to the power supplies 37 and 38. The control unit 39 can control the value of the current supplied from the current supply unit 15 to each LED and the on / off operation of the switch unit 11 and the switch unit 12 in synchronization with these setting signals.

  Note that the specific waveforms of the setting signals # 39a, # 39b, # 39c, and # 39d are not limited to the present embodiment, but as these setting signals, for example, signals having a rectangular waveform are used. it can.

  Also in the driving device 30, as in the first embodiment, the LED can emit light in any one of the first light emission mode and the second light emission mode. Since details of these light emission modes have already been described in the first embodiment, the description thereof is omitted here, and in the following, a method of adjusting the current flowing through the LED (R) 100, the LED (G) 200, and the LED (B) 300 Will be described.

(Method for adjusting the current value flowing through each LED)
It is preferable to adjust the current value flowing through each LED by the following steps.

(Step S201)
First, the value of the base current supplied by the power supplies 37 and 38 is set lower than the value assumed as the final base current.

(Step S202)
Subsequently, the value of the drive voltage supplied by the current supply unit 15 is adjusted so that the brightness of the light emitted from the LED (B) 300 becomes a predetermined brightness.

(Step S203)
Subsequently, the value of the base current supplied from the power sources 37 and 38 is increased, and the color mixture of the light emitted from the LED (R) 100, the LED (G) 200, and the LED (B) 300 is adjusted to be white. . In this state, the current value of the current flowing through each LED is the optimum value when white light is emitted.

(Effects produced by the driving device 30)
The drive device 30 has the same effect as the drive device 20 according to the second embodiment. More specifically,
Since the drive device 30 includes the transistor 31 and the transistor 32, the balance of each color when white light is emitted in the second light emission mode is adjusted by controlling the value of the base current supplied to these transistors. Is easy. In general, the luminous efficiency of LEDs has temperature dependence, but according to the driving device 30, the white color does not change even if the temperature changes by changing the value of the base current according to the temperature. can do.

  Moreover, since the light emission efficiency of each LED generally has individual dependence, when the LED to be used is replaced, the white color may change. According to the drive device 30, even in such a case, the white color can be kept constant by adjusting the value of the base current.

(Additional notes regarding Embodiment 3)
In the above description, the configuration in which the variable portion R1 and the variable portion R2 are connected to the LED (R) 100 and the LED (G) 200 has been described as an example, but this does not limit the present embodiment. More generally, among the LED (R) 100, the LED (G) 200, and the LED (B) 300, the resistor R1 and the resistor R2 are connected to an LED other than the LED having the highest operating voltage. That's fine.

  Moreover, in the above description, although the resistance part R1 and resistance part R2 gave the example of the structure connected to the cathode side of LED (R) 100 and LED (G) 200, this embodiment is limited to this. The resistor R1 and the resistor R2 may be configured to be connected to the anode side of the LED (R) 100 and the LED (G) 200.

  Moreover, in the above description, although the drive device 30 gave the example of the structure provided with two resistance parts, resistance part R1 and resistance part R2, this embodiment is not limited to this. In general, the operating voltage of each LED can vary depending on the material constituting the LED, the size of the chip on which the LED is mounted, and the like. Depending on the material and chip size, either one of the resistor R1 and the resistor R2 can be omitted.

(Additional notes regarding the first to third embodiments)
As described above, in the first to third embodiments, the case where three LEDs of the red LED, the green LED, and the blue LED are used as the light source has been described as an example. However, the above embodiment is not limited to this. Any light source capable of emitting a plurality of primary colors may be used. For example, a high-pressure mercury lamp or the like may be used as the light source. Further, the number of light sources is not limited to three.

  Moreover, the LED projector provided with the light source device which concerns on this Embodiment 1-3 is also contained in the category of the said embodiment.

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

  The present invention can be suitably used for a light source driving device that drives a light source. For example, it can be suitably used for an LED projector using an LED as a light source.

1, 2, 3 Light source device 10, 20, 30 Drive device (light source drive device)
11, 12 Switch part 13, 14 Resistance (resistance part)
15 Current supply unit 16, 23, 39 Control unit 21, 22 Variable resistance (resistance unit)
31, 32 Transistors 33, 34, 35, 36 Resistors 37, 38 Power supply 100 LED (R)
200 LED (G)
300 LED (B)

Claims (12)

A light source driving device that drives a plurality of light sources that individually emit light of each color,
A current supply unit capable of supplying current to the plurality of light sources;
A resistance unit individually connected to at least one of the plurality of light sources;
A first switch unit that selectively connects or disconnects the current supply unit to any one of the plurality of light sources without the resistor unit;
A second switch unit for connecting or blocking the current supply unit to or from each light source to which the resistor unit is connected via the resistor unit;
A control unit for controlling the current supply unit, the first switch unit, and the second switch unit;
With
The control unit
In the first light emission mode, the second switch unit is set to a cut-off state, and any one of the plurality of light sources is connected to the current supply unit by the first switch unit,
In the second light emission mode, the second switch unit is set to a connected state, and a light source to which the resistor unit is not connected is connected to the current supply unit by the first switch unit.
A light source driving device characterized by that. The resistor is individually connected to a light source other than the light source having the highest operating voltage among the plurality of light sources.
The light source driving device according to claim 1. The control unit controls on / off of the first and second switch units and a current value of a current supplied by the current supply unit in synchronization.
The light source driving device according to claim 1, wherein The resistance portion is composed of a resistor having a predetermined resistance value.
The light source driving device according to claim 1, wherein the light source driving device is a light source driving device. The resistor section is composed of a variable resistor whose resistance value can be controlled.
The light source driving device according to claim 1, wherein the light source driving device is a light source driving device. The resistor section includes a transistor capable of controlling a current flowing through the light source.
The light source driving device according to claim 1, wherein the light source driving device is a light source driving device.   A light source driving device according to any one of claims 1 to 6 and a plurality of light sources that individually emit light of each color, wherein the plurality of light sources are driven by the light source driving device. Light source device. The number of the light sources is 3, and each light source emits three primary colors individually.
The light source device according to claim 7. The three primary colors are red, green, and blue.
The light source device according to claim 8. Each of the plurality of light sources is a light emitting diode.
The light source device according to claim 7, wherein the light source device is a light source device.   A projector comprising the light source device according to claim 7. A current supply unit capable of supplying current to a plurality of light sources that individually emit light of each color;
A resistance unit individually connected to at least one of the plurality of light sources;
A first switch unit that selectively connects or disconnects the current supply unit to any one of the plurality of light sources without the resistor unit;
A second switch unit for connecting or blocking the current supply unit to or from each light source to which the resistor unit is connected via the resistor unit;
A method of controlling a light source driving device comprising:
In the first light emission mode, the second switch unit is set to a cut-off state, and any one of the plurality of light sources is connected to the current supply unit by the first switch unit,
In the second light emission mode, the second switch unit is set to a connected state, and a light source to which the resistor unit is not connected is connected to the current supply unit by the first switch unit.
A control method characterized by that.

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