JP2009087549A - Lamp lighting device, LCD projector - Google Patents

Abstract

A discharge lamp lighting device having a high communication speed is realized even when a photocoupler having the same performance is used by reducing the amount of data transmitted and received with a set unit.
A DC voltage of a power source 11 is stepped down by a converter 12, converted into an AC voltage by an inverter 15, a high voltage is generated by a lamp starting circuit 16, and a discharge lamp 17 is turned on. The control circuit 20 generates a driving signal d that alternately turns on and off the switching signal a and the switching elements SW1, SW2, SW3, and SW4. The switching signal a is generated based on the duty of the control signal SCI supplied to the interface circuit 19, and the drive signal d is generated at a timing based on the rise of the control signal SCI including information such as lighting, extinction, and dimming. The control circuit 20 outputs flag signals FG having different duties based on the temperature information e from the lamp lighting control unit 100. Based on the flag signal FG, the state of the lamp lighting control unit 100 can be grasped on the setting unit 200 side.
[Selection] Figure 1

Description

  The present invention relates to a lamp lighting device that stably controls lighting of a high-intensity discharge lamp used in a DLP (registered trademark) (Digital Light Processing) type liquid crystal projector, and a liquid crystal projector using the same.

Two-way communication between the lamp lighting device of the stabilized power source that controls and controls the discharge lamp on the conventional liquid crystal projector and the set unit that gives various commands and data to this lamp lighting device is a pair of signal lines via a photocoupler. It was done in. (For example, Patent Document 1)
JP 2007-149635 A

  In the technique of Patent Document 1 described above, the lamp lighting device is arranged on the primary side in terms of safety standards, and the set-side microcomputer is arranged on the secondary side. The signal transmission between the primary and secondary has a drawback that the signal transmission speed is low in the photocoupler recognized in the safety standard. For this reason, as shown in FIG. 9 of Patent Document 1, the time required for transmission / reception of data and commands is 44 ms. Since the lamp lighting device reacts after this time elapses, a long time is required for the communication time and the processing of the microcomputer, and it becomes impossible to synchronize with the color boundary of the color filter in accordance with the inversion time of the lamp current. If this synchronization is not achieved, there is a problem that images are not displayed correctly.

  An object of the present invention is to use a lamp lighting device for a discharge lamp that improves communication speed even when a photocoupler having the same performance is used by reducing the amount of data transmitted to and received from the set unit side, and the lamp lighting device. It is to provide a liquid crystal projector based on the DLP method.

  In order to solve the above-described problems, a lamp lighting device according to the present invention boosts or steps down an input DC voltage based on a switching signal, converts it to a desired DC voltage and power, and outputs the DC voltage. An inverter that converts the voltage into a high-pressure discharge lamp, a lamp start circuit that applies a high voltage to the discharge lamp at the time of starting the lamp, generates the switching signal, and varies the duty of the switching signal, A control circuit that performs dimming control of the discharge lamp, and an interface circuit that generates a duty flag signal based on operation information supplied to the control circuit.

  According to another aspect of the invention, there is provided a liquid crystal projector having the above-described configuration, and a DLP type image projection that uses the discharge lamp as a light source and switches and displays each color-separated image based on light emitted from the light source. And an apparatus main body.

  In the lamp lighting device of the present invention, a lamp lighting device suitable for a DLP type liquid crystal projector can be realized by improving the communication speed even when a photocoupler having the same transmission speed is used.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  1 and 2 are diagrams for explaining a first embodiment of the lamp lighting device according to the present invention. FIG. 1 is a circuit configuration diagram, and FIG. 2 is a specific circuit diagram of a main part of FIG.

  In FIG. 1, reference numeral 1000 denotes a lamp lighting device, 100 denotes a lighting control unit for lighting the lamp, and 200 denotes a set unit.

  Reference numeral 11 of the lamp lighting device 1000 is a DC power source, and supplies the DC voltage of the power source 11 to the converter 12 that steps down the DC voltage. The converter 12 is connected from the positive electrode of the power supply 11 to the cathode of a diode D whose anode is grounded and one end of the choke coil L via a switching element SW made of, for example, a MOS FET transistor. The other end of the coil L is grounded via the smoothing capacitor C1 and also grounded via the lamp voltage detector 13. A lamp current detector 14 is interposed between the ground side of the lamp voltage detector 13 and the ground side of the capacitor C1. The switching element SW is on / off controlled based on the switching signal a.

  The output of the converter 12 is connected to the full-bridge switch elements SW1 and SW4 that combine the switch elements SW1 to SW4 by, for example, MOS type FET transistors that constitute the inverter 15 that converts the DC voltage output from the converter 12 into an AC voltage. . The switch element SW1 is grounded via the switch element SW3, and the switch element SW4 is grounded via the switch element SW2. The connection point of the switch elements SW1 and SW3 is connected to one input of a lamp starting circuit 16 that generates a high voltage pulse voltage when the lamp is lit. The connection point of the switch elements SW4 and SW2 is connected to the other input of the lamp starting circuit 16. The switch elements SW1 and SW2 are turned on / off at the same time and the switch elements SW3 and SW4 are turned on / off at the same time. The output of the lamp starting circuit 16 is supplied to the high pressure discharge lamp 17.

  Reference numeral 18 of the setting unit 200 is an input terminal. A control signal SCI is input to the input terminal 18, and the control signal SCI is input to the interface circuit 19. The control signal SCI not only becomes a dimming control signal by changing the duty, but also becomes a control signal for turning on, turning off, and synchronizing the lamp 17. The interface circuit 19 derives a DC power having a value based on the duty of the control signal SCI as the control signal CL in addition to the on / off / synchronized control signal SCI ′ based on the input control signal SCI. 20 is supplied.

  The control circuit 20 outputs a switching signal a for turning on / off the switching element SW and a driving signal d for driving the switching elements SW1 to SW4. Further, the control circuit 20 includes a voltage detection signal b of the lamp voltage detection unit 13 of the converter 12, a current detection signal c of the lamp current detection unit 14, temperature information e of the converter 12 and the inverter 15, and lamp temperature information f of the lamp 17. Supplied respectively.

  Further, the control circuit 20 generates a flag signal FG ′ signal based on the voltage detection signal b, the current detection signal c, the temperature information e, and the lamp temperature information f, and supplies it to the interface circuit 19. The interface circuit 19 generates flag signal FG information based on the flag signal FG ′ signal and outputs it to the output terminal 21. The temperature information e and the lamp temperature information f supplied to the control circuit 20 are operation information of the lamp lighting device 1000.

  FIG. 2 shows a specific circuit example of the interface circuit 19. In FIG. 2, the interface circuit 19 supplies the control signal SCI input to the input terminal 18 to the light emitting diode of the photocoupler Pa configured from the light emitting diode of the photocoupler Pa and the phototransistor, and the phototransistor side of the photocoupler Pa. The control signals SCI ′ and CL are supplied to the control circuit 20 as outputs from the interface circuit 19. The control circuit 20 generates a switching signal a and a driving signal d based on the control signal SCI 'and outputs them.

  The control circuit 20 outputs a flag signal FG 'based on the input voltage detection signal b, current detection signal c, temperature information e, and lamp temperature information f. This flag signal FG ′ signal is supplied to the phototransistor of the photocoupler Pb of the interface circuit 19. From the light emitting diode of the photocoupler Pb, a flag signal FG generated based on the flag signal FG ′ is supplied to the output terminal 21 as an output of the interface circuit 19.

  Next, the operation of FIGS. 1 and 2 will be described with reference to the timing charts of FIGS.

  First, the case where the unlit lamp 17 is turned on will be described. When the control signal SCI is supplied to the interface circuit 19, the interface circuit 19 outputs the control signal SCI ′ and the control signal CL to the control circuit 20. In the control circuit 20, for example, the switching signal a shown in FIG. 3A based on the table information stored in the control circuit 20 in advance is generated, and the switch element SW of the converter 12 is driven. Further, as shown in FIG. 3D, the control circuit 20 drives the switch elements SW1 to SW4 with the driving pulse d of the starting / preheating lighting period Hf of about 17 kHz for 2 seconds, for example, and in the starting / preheating lighting period Hf. The switch elements SW1 and SW2 are turned on when the drive pulse d is at the Hi level and turned off when the drive pulse d is at the Lo level, and the switch elements SW3 and SW4 are turned on when the drive pulse d is at the Lo level and turned off when the drive pulse d is at the Hi level. .

  In the converter 12, the switching element SW is turned on / off based on the switching signal a to convert the DC voltage of the power supply 11 into a DC voltage and DC power based on the duty of the switching signal a and output to the inverter 15.

  The direct current voltage input to the inverter 15 turns on / off the switch elements SW1, SW2 and SW3, SW4 alternately by the drive pulse d in the start / preheat lighting period Hf, so that the lamp start circuit 16 in this period is supplied with the lamp 17 High voltage pulse voltage is supplied to The lamp 17 breaks the insulation between the electrodes constituting the lamp 17 by the high voltage pulse voltage, starts lighting, and shifts to a preheating operation. During this period, when the lamp power is small, constant voltage control is performed, and when the lamp power is large, constant power control is performed.

  Next, the dimming at the time of normal lighting, turning off from the normal lighting state, and normal lighting will be described.

  First, consider a case where the control signal SCI having a duty of 80% shown in FIG. The interface circuit 19 outputs the control signal SCI ′ and a DC voltage control signal CL based on the duty 80% to the control circuit 20. The control circuit 20 generates a duty switching signal a based on the DC voltage value of the control signal CL, and switches the switch element SW. In the converter 12, the DC voltage of the power supply 11 is converted based on the duty of the switching signal a so as to become, for example, DC power 100 W, and is output to the inverter 15.

  The DC power input to the inverter 15 drives the lamp 17 by alternately turning on / off the switch elements SW1, SW2 and SW3, SW4 with the drive pulse d of the normal lighting period Lf of about 90 Hz, for example.

  As shown in FIG. 4D, the drive pulse d in the normal lighting period Lf is a pulse that is turned on / off in synchronization with the rising edge of the control signal SCI '.

  When the lamp 17 is turned off, if the period of the Lo level of the control signal SCI ′ continues for, for example, 5 milliseconds or more, the control circuit 20 can stop the output of the drive pulse d and the like assuming that the turn-off signal is input. Become.

  When dimming is performed in the normal lighting state, when the control signal SCI having a duty of 50% shown in FIG. 4 (tb) is input to the interface circuit 19, the control circuit 20 receives the control signal SCI ′ and the control signal. A control signal CL of DC power based on the duty of SCI ′ is output to the control circuit 20. The control circuit 20 generates a duty switching signal a based on the DC voltage value of the control signal CL, and switches the switch element SW. In the converter 12, it is converted into DC power based on the duty of the switching signal a and output to the inverter 15.

  The DC power at this time is a lower value than when the duty is 80%. The drive signal d for driving the inverter 15 is a pulse that is turned on / off in synchronization with the rising edge of the control signal SCI as shown in FIG. 4D, and is the same pulse as in the case of the control signal SCI with a duty of 80%. is there. Therefore, the output power of the lamp 17 is, for example, 80 W, and dimming with the power reduced by 20% is possible.

  Similarly, when the control signal SCI having a duty of 20% shown in FIG. 4 (tc) is input to the interface circuit 19, the value of the DC power supplied to the inverter 15 decreases. The drive signal d for driving the inverter 15 is a pulse that is turned on / off in synchronism with the rising edge of the control signal SCI as shown in FIG. 4D, and the control signal SCI with a duty of 80% or 50%. The same pulse. With the control signal SCI having a duty of 20%, the output power of the lamp 17 can be set to 50 W, for example.

  As described above, the control signal SCI can be dimmed by changing the duty in addition to starting and stopping the lighting of the lamp 17.

  Note that the control signal SCI shown in FIGS. 4 (ta) to 4 (tc) does not show a duty of 100%. Of course, the control signal SCI can be set to a duty of 100% in a state where the light is not dimmed. The state of dimming can be arbitrarily set, and the dimming amount and lighting frequency can be arbitrarily changed.

  Further, when the lamp is stopped, the control signal SCI is at the Lo level for 5 ms or more, for example, but may be at the Hi level.

  Next, the control of the control circuit 20 when the lamp lighting device temperature abnormality signal is output will be described.

  In FIG. 5, b indicates the lamp voltage detected by the lamp voltage detector 13, c indicates the lamp current detected by the lamp current detector 14, and e indicates temperature information of the converter 12 and the inverter 15. FG 'is a flag signal generated from the control circuit 20 based on the lamp voltage b, the lamp current c, and the temperature information e. The flag signal FG ′ is supplied to the interface circuit 19.

  In the case of the flag signal FG ′ during the extinguishing period in which the lamp voltage b and the lamp current c do not exist, the flag signal FG of Hi (100% Duty) is output from the interface circuit 19. In the case of the flag signal FG ′ in the lighting period in which the lamp 17 is normally lit and the lamp voltage b and the lamp current c are normally present, the Lo (0% Duty) flag signal FG is output from the interface circuit 19.

  Next, when the temperature of the lamp lighting device such as the converter 12 or the inverter 15 rises and the temperature information e reaches the temperature abnormality detection point Bt, the flag signal FG is output with a 50% duty.

  That is, the flag signal FG output from the interface circuit 19 is information having contents shown in FIG. As a result, different duty values are defined as information contents defined in advance, and information on the lamp lighting device and the discharge lamp can be read from the flag signal FG based on the duty of the flag signal FG.

  In this embodiment, by reducing the amount of data transmitted and received as shown in FIG. 5, even when a photocoupler with the same performance is used, the communication speed between the lamp lighting control unit and the set unit is reduced to about several microseconds. Is possible.

  FIG. 7 is an explanatory diagram for explaining a second embodiment of the lamp lighting device of the present invention. This embodiment relates to information of the flag signal FG output from the control circuit 20 when an abnormal temperature occurs in the lamp 17 and a lamp temperature abnormal signal is supplied to the control circuit 20.

  In FIG. 7, b is the lamp voltage detected by the lamp voltage detector 13, c is the lamp current detected by the lamp current detector 14, e is the temperature information of the converter 12 and the inverter 15, and f is the temperature information of the lamp 17. The lamp temperature information and flag signal FG are signals generated from the control circuit 20 based on the lamp voltage b, the lamp current c, and the lamp temperature information f.

  In a light extinction period in which the lamp voltage b and the lamp current c do not exist, a Hi (100% Duty) flag signal FG is output. During a lighting period in which the lamp 17 is normally lit and the lamp voltage b and the lamp current c are normally present, a Lo (0% Duty) flag signal FG signal is output.

  Next, when the temperature of the lamp 17 rises and the temperature detection signal reaches the temperature abnormality detection point Lt, the flag signal FG is output with a duty of 25%.

  That is, the flag signal FG output from the interface circuit 19 is information having the contents shown in FIG. Thus, by defining different duties as information in advance, it is possible to read from the flag signal FG as state information of the lamp lighting device and the discharge lamp based on the duty of the flag signal FG.

  8 to 10 are for explaining a third embodiment of the lamp lighting device according to the present invention. FIG. 8 is a block diagram corresponding to FIG. 2, and FIG. 9 is for explaining the operation of FIG. FIG. 10 is an explanatory diagram for explaining an output signal of a main part of FIG. The same components as those in the above embodiment are denoted by the same reference numerals, and different portions will be described here.

  That is, as shown in FIG. 8, for example, a 5 V bias source E and resistors R1 and R2 connected in series are connected between the outputs of the phototransistors of the photocoupler Pb of the interface circuit 19, and the bias source E and the resistors connected in series are connected. A capacitor C3 is connected in parallel to R1. The connection point of the resistors R1 and R2 is connected to the output terminal 21.

  During the extinguishing period of FIG. 9 in which the lamp voltage b and the lamp current c supplied to the interface circuit 19 do not exist, a flag signal FG of HIGH (100% Duty) 5V is output from the output terminal 21. During a lighting period in which the lamp 17 is normally lit and the lamp voltage b and the lamp current c are normally present, a LOW (0% Duty) 0V flag signal FG is output.

  Next, when the temperature of the temperature information e from the lamp lighting control unit 100 rises and the temperature information e of FIG. 9E reaches the temperature abnormality detection point Bt, the 50% duty is smoothed (FIG. 9 (FG)). The 2.5V flag signal FG shown in FIG.

  The flag signal FG output from the interface circuit 19 is information having the contents shown in FIG. As a result, different duty values are defined as information contents, and it is possible to read the lamp lighting device and lamp information from the flag signal FG based on the duty of the flag signal FG.

  FIG. 11 is an explanatory view corresponding to FIG. 9 for explaining a fourth embodiment relating to the lamp lighting device of the present invention.

  This embodiment relates to information of the flag signal FG output from the control circuit 20 when an abnormal temperature occurs in the lamp 17 and a lamp temperature abnormal signal is supplied to the control circuit 20.

  That is, in the extinguishing period in which the lamp voltage b and the lamp current c do not exist in FIGS. 11B and 11C, the HIGH (100% Duty) 5V flag signal FG is output as shown in FIG. In the lighting period in which the lamp 17 is normally lit and the lamp voltage b and the lamp current c in FIG. 11B and FIG. 11C are normally present, LOW (0% Duty) 0V as shown in FIG. A flag signal FG is output.

  Next, when the lamp temperature rises and the lamp temperature information f reaches the temperature abnormality detection point Lt as shown in FIG. 11 (f), a 1.25V flag signal FG with 25% duty smoothed is output. Is done.

  Also in this embodiment, different duty values are defined as information contents, and information on the lamp lighting device and the lamp can be read from the flag signal FG based on the duty of the flag signal FG.

  Among the lamp lighting devices of the present invention described above, the first and second embodiments may be combined, or the third and fourth embodiments may be combined. The different duty types are 0%, 25%, 50%, 75%, and 100%. However, the duty type is not limited to this, and the state of the lamp lighting control unit is increased or decreased as necessary. It is also possible to obtain information on the set side.

  Further, the temperature information e is the temperature information of the converter 12 and the inverter 15, but may be temperature information detected from either one. Further, although the chart is such that the lamp is stopped when a temperature abnormality is detected, the lamp lighting control unit side can also stop by the control signal SCI from the set unit side without stopping the lamp.

  FIG. 12 is a schematic configuration diagram for explaining an embodiment relating to the liquid crystal projector of the present invention. FIG. 12 shows the configuration of a DLP liquid crystal projector equipped with the lamp lighting device shown in FIGS.

  The projector device 300 reflects the light of the lamp 17 that is turned on by the lamp lighting device 400 toward the color wheel assembly 302 and the color wheel 301 in which the disk-shaped color wheel 301 is attached to the rotating part of the motor. Irradiate. A projection optical unit 306 that projects light from a digital micromirror device 304 that reflects light transmitted through the color wheel 301 onto a screen 305 is provided.

  The color wheel 301 is a filter that transmits light in the frequency bands of R (red), G (green), and B (blue) in three color regions divided by 120 degrees with respect to the circumferential direction. To rotate at about 10,000 revolutions per minute. The digital micromirror device 304 is provided with a plurality of fine reflection mirrors that can be changed in posture in two dimensions. The light sequentially emitted from the color wheel 301 in any of R, G, and B is guided to each reflecting mirror of the digital micromirror device 304 via the condenser lens 308, and projection optics according to the posture of each reflecting mirror. Only light that is reflected toward a predetermined position different from the unit 306 and the projection optical unit 306 and is incident on the projection optical unit 306 is projected onto the screen 305.

  At this time, the digital micromirror device 304 is controlled in synchronization with the rotation angle of the color wheel 301 based on a signal input from the outside, and the posture of each reflecting mirror is changed at high speed. Thereby, in the projector device 300, the R image, the G image, and the B image are sequentially switched at a high speed in accordance with the input signal, and a color image is displayed on the screen 305.

  A drive signal d for driving the inverter of the lamp lighting device 400 is used as a signal synchronized with the rotation angle of the color wheel 301.

  According to this embodiment, since the state information on the lamp lighting device side can be obtained quickly with a small amount of data, it is possible to reliably switch the lamp current switching of the lamp lighting device and the color wheel, and correct image display Can contribute to the realization of

The circuit block diagram for demonstrating 1st Embodiment regarding the lamp lighting device of this invention. The block diagram for demonstrating one more specific structural example of the interface circuit of FIG. Explanatory drawing for demonstrating the operation | movement of FIG. Explanatory drawing for demonstrating the operation | movement of FIG. 1 and FIG. Explanatory drawing for demonstrating the operation | movement of FIG. FIG. 3 is an explanatory diagram for explaining information of a flag signal FG in FIG. 2. Explanatory drawing for demonstrating 2nd Embodiment of the lamp lighting device of this invention. The block diagram for demonstrating 3rd Embodiment of the lamp lighting device of this invention. Explanatory drawing for demonstrating the operation | movement of FIG. Explanatory drawing for demonstrating the information of the flag signal FG of FIG. Explanatory drawing for demonstrating 4th Embodiment regarding the lamp lighting device of this invention. The conceptual diagram for demonstrating one Embodiment regarding the liquid crystal projector of this invention.

Explanation of symbols

1000 Lamp Lighting Device 100 Lamp Lighting Control Unit 200 Set Unit 11 Power Supply 12 Converter 13 Lamp Voltage Detection Unit 14 Lamp Current Detection Unit 15 Inverter 16 Lamp Start Circuit 17 Lamp 18 Input Terminal 19 Interface Circuit 20 Control Circuit 21 Output Terminals SCI, SCI ′ , CL control signals FG, FG ′ flag signal 300 projector device 301 color wheel 302 color wheel assembly 303 reflector 304 digital micromirror device 305 screen 306 projection optical unit 308 condenser lens 400 discharge lamp lighting device

Claims (3)

A converter that boosts or steps down an input DC voltage based on a switching signal, converts it to a desired DC voltage and electric power, and outputs it;
An inverter that converts the DC voltage into an AC voltage and puts it into a high-pressure discharge lamp;
A lamp starting circuit for applying a high voltage to the discharge lamp at the time of starting the lamp;
A control circuit that generates the switching signal, varies a duty of the switching signal, and performs dimming control of the discharge lamp;
An lamp circuit comprising: an interface circuit that generates a duty flag signal based on operation information supplied to the control circuit.   The lamp lighting device according to claim 1, wherein the operation information is generated based on a temperature state of at least one of the converter, the inverter, and the lamp. The discharge lamp lighting device according to claim 1 or 2,
A liquid crystal projector comprising: a DLP image projection apparatus main body that uses the discharge lamp as a light source and switches and displays each color-separated image based on light emitted from the light source.

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