JP2007234407A - Light source device having a plurality of reflecting surfaces - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve utilization efficiency of light while reducing adverse affect caused by installation of a plurality of reflecting surfaces, in a light source device having a plurality of reflecting surfaces. <P>SOLUTION: This light source device is provided with a light source part having light emitting parts arranged at a plurality of positions on a first virtual plane nearly perpendicular to the irradiation direction of the light source device. The light source device is also provided with a first reflecting part having a first reflecting surface being a reflecting surface of a concave curved surface shape and having a shape forming a boundary of a space including the light emitting parts in its inside along with a second virtual plane nearly perpendicular to the irradiation direction. In addition, the light source device is provided with a second reflecting part having a second reflecting surface of a convex curved surface shape positioned on the irradiation direction side with respect to the light emitting parts in the space, and directed in a direction opposite to the irradiation direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a light source device, and more particularly to a light source device having a plurality of reflecting surfaces that reflect light emitted from a light emitting unit.

  Various light source devices are used for vehicle headlights, projectors for projecting images, and the like. The light source device has a concave curved reflection surface (first reflection surface) oriented in the irradiation direction in order to reflect a part of the light emitted from the light emitting unit toward the predetermined irradiation direction. There is.

  Further, a light source device having a first reflection surface, which is further located on the irradiation direction side with respect to the light emitting unit and has another reflection surface (second reflection surface) facing the light emitting unit. Known (for example, Patent Document 1). In Patent Document 1, in a light source device having a first reflection surface and a second reflection surface, the direction of light emitted from the light source device is changed by variously changing the shape of the second reflection surface. Is disclosed.

JP-A-62-180901

  In the conventional light source device described in Patent Document 1, the shape of the second reflecting surface is oriented in a planar shape perpendicular to the irradiation direction of the light source device or in a direction opposite to the irradiation direction (hereinafter referred to as “anti-irradiation direction”). In the case of the concave curved surface shape, most of the light emitted from the light emitting part is reflected in the direction of returning to the vicinity of the light emitting part on the second reflecting surface. For this reason, in this case, part of the light reflected by the second reflecting surface is converted into heat in the light emitting section, which may cause light loss and adverse effects on the light emitting section. For example, when the light emitting unit is configured using a discharge tube, the heat generated by the reflected light disturbs the temperature characteristics of the discharge unit, making the discharge state unstable and shortening the life of the electrode. There was a fear. In addition, a portion of the light reflected by the second reflecting surface becomes turbulent light near the light emitting portion, causing light distortion (shadow) on the first reflecting surface, and thus light unevenness occurs in the light emitted from the light source device. There was a fear.

  On the other hand, in the conventional light source device described in Patent Document 1, when the shape of the second reflecting surface is a convex curved surface shape facing the anti-irradiation direction, the light emitted from the light emitting unit is the second. In the reflection surface, the light is reflected in the direction of diffusing further to the surroundings. Therefore, in this case, there is a problem that the light utilization efficiency is lowered.

  The present invention has been made to solve the above-described conventional problems, and in a light source device having a plurality of reflecting surfaces, improves the light utilization efficiency while reducing the adverse effects associated with the installation of the plurality of reflecting surfaces. It is an object to provide a technology that makes it possible.

In order to solve at least a part of the above problems, the light source device of the present invention includes:
A light source unit having light emitting units arranged at a plurality of positions on a first virtual plane substantially orthogonal to the irradiation direction of the light source device;
A first concave reflection surface having a first reflection surface having a shape that forms a boundary of a space including the light emitting portion together with a second virtual plane substantially orthogonal to the irradiation direction of the light source device. The reflective part of
A second reflecting portion that is located on the irradiation direction side with respect to the light emitting portion in the space and has a second reflecting surface having a convex curved shape facing in a direction opposite to the irradiation direction.

  The light source device includes a second reflecting portion having a second reflecting surface located on the irradiation direction side with respect to the light emitting portion. The second reflecting surface is formed in a convex curved surface shape facing in the direction opposite to the irradiation direction. Therefore, of the light emitted from the light emitting unit, the ratio of the light that is reflected on the second reflecting surface and then returns to the vicinity of the light emitting unit again is relatively small. Therefore, in this light source device, conversion of the light reflected by the second reflecting surface into heat can be suppressed, the light utilization efficiency can be improved, and adverse effects associated with the installation of a plurality of reflecting surfaces can be achieved. Can be reduced.

  Moreover, the light source part of this light source device has the light emission part arrange | positioned in the several position on the 1st virtual plane substantially orthogonal to the irradiation direction of a light source device. Therefore, compared to a conventional light source device having only one light emitting unit, the direction of reflected light on the second reflecting surface is set to a direction that suppresses diffusion as a whole. Therefore, in this light source device, the light use efficiency can be improved.

In the light source device,
The light source unit and the second reflecting unit may be configured such that a virtual substantially point light source is formed at a position closer to the irradiation direction than the second reflecting surface.

  In this way, a virtual substantially point light source can be formed, and the light utilization efficiency can be further improved.

In the light source device,
For each of the plurality of light emitting units, the second reflecting surface is configured such that reflected light emitted from the light emitting unit and directly reflected by the second reflecting surface is an arbitrary point on the second reflecting surface, and The position and the shape may be set so as to pass on a straight line connecting a predetermined convergence point located on the irradiation direction side from the second reflecting surface.

  In this way, a virtual substantially point light source located at a predetermined convergence point can be formed.

In the light source device,
The light source unit may be configured such that the light emitting units at a plurality of positions can emit light simultaneously.

  In this way, the light source unit becomes a light source that is closer to the surface light source that emits parallel rays, and thus it is possible to make the virtual substantially point light source closer to the point light source. Therefore, the light utilization efficiency can be further improved.

  The present invention can be realized in various modes, and can be realized in the form of, for example, a light source device, a projection display device including the light source device, and an illumination device including the light source device.

Next, embodiments of the present invention will be described in the following order based on examples.
A. First embodiment:
B. Second embodiment:
C. Third embodiment:
D. Fourth embodiment:
E. Variation:

A. First embodiment:
FIG. 1 is an explanatory diagram schematically showing the configuration of a light source device 600 as a first embodiment of the present invention. FIG. 1 shows a cross section parallel to the irradiation direction of the light source device 600 (direction from left to right in FIG. 1). The light source device 600 includes a discharge tube 640, a first reflection unit 660, a second reflection unit 610, a drive control unit 1000, and a power line 810 that connects the discharge tube 640 and the drive control unit 1000. Yes. The light source device 600 may further include a lens 620. The light source device 600 of the first embodiment can be applied to, for example, a light source of a projection display device such as a projector, a lighting device for vehicles or general use.

  The first reflecting portion 660 has a first reflecting surface RF1 formed in a concave curved surface shape facing the irradiation direction. The first reflecting surface RF1 is formed in a substantially rotating parabolic surface shape centered on an axis parallel to the irradiation direction (hereinafter referred to as “center axis CA”). A hollow portion 670 is formed between the first reflecting surface RF1 of the first reflecting portion 660 and the planar cover 662 substantially parallel to the central axis CA. That is, the first reflecting surface RF1 and the cover 662 form a boundary of the hollow portion 670. For example, nitrogen gas is sealed in the hollow portion 670. Further, in the first reflecting portion 660, a base portion 650 for supporting the discharge tube 640 is provided in the vicinity of the end portion on the side opposite to the irradiation direction (hereinafter referred to as “counter-irradiation direction”).

  The discharge tube 640 is fixed to the base portion 650 of the first reflecting portion 660 such that the tip on the side where a discharge space described later is formed protrudes into the hollow portion 670 of the first reflecting portion 660. The discharge tube 640 is connected to the drive control unit 1000 through three power supply lines 810. The detailed configuration of the discharge tube 640 will be described later. The discharge tube 640 in the present embodiment corresponds to the light source unit in the present invention.

  The second reflecting portion 610 is arranged in the irradiation direction side with respect to the discharge tube 640 in the hollow portion 670. The second reflecting portion 610 has a second reflecting surface RF2 that is formed in a convex curved surface shape that is directed in the anti-irradiation direction (that is, opposed to the discharge tube 640). The second reflecting surface RF2 is formed in a substantially rotating parabolic surface shape centered on the central axis CA.

  The drive control unit 1000 includes a digital signal output unit 100 and three voltage control units 200, and is configured as a three-phase drive circuit. The digital signal output unit 100 outputs a digital signal representing the waveform of the power signal supplied to the discharge tube 640. The voltage control unit 200 controls a voltage applied to an electrode terminal (described later) of the discharge tube 640 based on the digital signal output from the digital signal output unit 100. A detailed configuration of the drive control unit 1000 and a drive control method of the discharge tube 640 by the drive control unit 1000 will be described later. FIG. 1 shows the traveling direction (indicated by arrows) of light emitted from the discharge tube 640 and a point P related to the traveling direction, which will be described later.

  FIG. 2 is an explanatory diagram showing a detailed configuration of the discharge tube 640 in the first embodiment. 2A shows a cross section parallel to the irradiation direction of the discharge tube 640, and FIG. 2B shows a bb cross section of FIG. 2A. The discharge tube 640 includes a discharge vessel 641 formed in a substantially cylindrical shape using, for example, quartz glass. Three discharge spaces 642 having the same number as the number of phases of the drive control unit 1000 are formed in the vicinity of the tip of the discharge vessel 641 in the irradiation direction. The three discharge spaces 642 are respectively arranged at positions near three vertices of a substantially equilateral triangle on a virtual plane substantially perpendicular to the irradiation direction (see FIG. 2B). The discharge space 642 is a substantially spheroidal space, and mercury and argon gas, for example, are sealed therein.

  Inside the discharge vessel 641, three electrodes 643, metal foils 646, and electrode terminals 647 are accommodated in correspondence with each phase of the drive control unit 1000 (see FIG. 2A). . The electrode 643 and the electrode terminal 647 are formed using, for example, tungsten, and the metal foil 646 is formed using, for example, molybdenum. One electrode 643, one metal foil 646, and one electrode terminal 647 are connected to each other in this order. Each of the three electrode terminals 647 is connected to each of the three power supply lines 810 (FIG. 1).

  The electrode 643 includes a body portion 645 and a branch portion 644 (see FIG. 2A). The tip of the electrode 643 on the body portion 645 side is connected to the metal foil 646. On the other hand, the branch portion 644 of the electrode 643 has a bifurcated shape, and two tips (hereinafter referred to as “discharge ends DT”) protrude into different discharge spaces 642. The combinations of the two discharge spaces 642 where the two discharge ends DT of one electrode 643 are located are all different among the three electrodes 643 (see FIG. 2B). In other words, in each discharge space 642, a total of two discharge ends DT, that is, one discharge end DT of one electrode 643 and one discharge end DT of another electrode 643 are located. The two discharge ends DT located in each discharge space 642 form a discharge gap DG. In the discharge tube 640 of the present embodiment, the discharge ends DT of the electrodes 643 are arranged so that the three discharge gaps DG are positioned near the three apexes of a substantially equilateral triangle on a plane substantially perpendicular to the irradiation direction. In the discharge gap DG, as will be described later, discharge is performed according to control by the drive control unit 1000, and discharge light is generated. The combination of the two discharge ends DT located in each discharge space 642 in the present embodiment corresponds to a light emitting unit in the present invention.

  In the following description, when distinguishing each of the three electrodes 643, as shown in FIG. 2B, each electrode 643 is replaced with an electrode 643A (or “A pole”) and an electrode 643B (or “B” Pole ") and electrode 643C (or" C pole "). In addition, when other elements other than the electrodes 643 provided corresponding to the three electrodes 643 are distinguished from each other based on the correspondence with the electrodes 643, the other elements are represented. The code corresponding to the A pole is “A”, the code corresponding to the “B pole” is “B”, and the code corresponding to the “C pole” is “C”. Are respectively added.

  FIG. 3 is a conceptual diagram of the electrode 643 in the discharge tube 640 of the first embodiment. The three electrodes 643 (643A (A pole), 643B (B pole), 643C (C pole)) of the discharge tube 640 are arranged as shown in FIG. This corresponds to a delta electric circuit in which each of the three electrodes 643 is connected to the other two electrodes 643 through a capacitor C as shown in FIG.

  FIG. 4 is an explanatory diagram showing the configuration of the voltage control unit 200 in the drive control unit 1000 (FIG. 1). As shown in FIG. 4, each of the three voltage control units 200 corresponds to each of the three electrodes 643. The voltage control unit 200 (200A) corresponding to the electrode 643A (A pole) includes a level shifter 210A, two switching transistors 230Ap and 230An, and a boosting unit 250AB. The level shifter 210A amplifies two digital signals Ap and An supplied from the digital signal output unit 100 (FIG. 1). The first transistor 230Ap is turned on / off according to the value of the first digital signal Ap, and applies a positive voltage to the electrode terminal 647A in the on state. The second transistor 230An is turned on / off according to the value of the second digital signal An, and applies a negative voltage to the electrode terminal 647A in the on state. The drive terminal 240A between the transistors 230Ap and 230An is connected to the electrode terminal 647A through the booster 250AB. The configuration of the voltage control unit 200 (200B and 200C) corresponding to the electrode 643B (B pole) and the electrode 643C (C pole) is the same as the configuration of the voltage control unit 200A corresponding to the A pole.

  FIG. 5 is an explanatory diagram showing the configuration of the booster 250. FIG. 5A shows a transformer as a configuration example of the booster 250AB. As shown in FIG. 5A, the booster 250AB (FIG. 4) exists between the drive terminals 240A and 240B (FIG. 4) and the electrode terminals 647A and 647B (FIG. 4), and the drive terminals 240A and 240B. The voltage Vab between is amplified to a voltage VeAB between the electrode terminals 647A and 647B. The same applies to the booster 250BC and the booster 250CA (FIG. 4). That is, booster 250BC amplifies voltage Vbc between drive terminals 240B and 240C to voltage VeCB between electrode terminals 647B and 647C, and booster 250CA boosts voltage Vca between drive terminals 240C and 240A to electrode terminals 647C and 647A. Amplified to a voltage VeCA between. In FIG. 4, for the sake of convenience, the boosters 250AB, 250BC, and 250CA are shown as being between one electrode terminal 647 and one drive terminal 240, but the boosters 250AB, 250BC, and 250CA are actually Are arranged as shown in FIG.

  FIG. 6 is an explanatory diagram showing another configuration of the booster 250. As shown in FIGS. 6A and 6B, the booster 250AB can also be configured by the inductance and the capacitance. Other similar configurations can be employed for the booster 250BC and the booster 250CA.

  FIG. 7 is a timing chart when driving the light source device 600 of the first embodiment. 7 shows digital signals Ap, An, Bp, Bn, Cp, and Cn (hereinafter collectively referred to as “digital signals Ap to Cn”) output from the digital signal output unit 100 (FIG. 1) and the digital signal Ap. The change of the voltage and the amount of discharge light accompanying the change of .about.Cn are shown. Moreover, FIG. 8 is explanatory drawing which shows notionally the mode of the discharge current formed between each electrode. The symbols P1, P2,... Shown at the top of FIG. 7 represent the periods in the timing chart, and correspond to the symbols P1, P2,.

  For example, in the period P1 in the timing chart of FIG. 7, the digital signal output unit 100 (FIG. 1) outputs two digital signals Ap and Bn that are H level signals, and the other four digital signals An, Bp, Cp and Cn output L level signals. At this time, in the circuit shown in FIG. 4, the two transistors 230Ap and 230Bn are turned on, and the remaining four transistors 230An, 230Bp, 230Cp, and 230Cn are turned off. Therefore, an electrical path from the power source 220 to the ground of the B pole 643B through the A pole 643A is opened. At this time, as shown in FIG. 8A, a discharge current is generated from the A pole 643A toward the B pole 643B, and the current flows in the directions indicated by IA + and IB− in FIG.

  Note that in the drive terminal 240A of FIG. 4, if the voltage flowing current in the IA + direction is a positive voltage and the voltage flowing current in the IA− direction is a negative voltage, the voltage Va of the drive terminal 240A is positive in the period P1. (See FIG. 7 (g)). On the other hand, in the drive terminal 240B, if the voltage flowing current in the IB + direction is a positive voltage and the voltage flowing current in the IB− direction is a negative voltage, the voltage Vb of the drive terminal 240B is negative in the period P1 (FIG. 7). (See (h)). The voltage VeAB between the electrodes 643A and 643B (hereinafter referred to as “interelectrode voltage VeAB”) is positive (see FIG. 7J).

  Similarly, in the period P2 in the timing chart of FIG. 7, in the digital signal output unit 100 (FIG. 1), the three digital signals Ap, Bn, Cn are at the H level, and the other three digital signals An, Bp, Cp Outputs an L level signal. At this time, in the circuit shown in FIG. 4, the three transistors 230Ap, 230Bn, and 230Cn are turned on, and the remaining three transistors 230An, 230Bp, and 230Cp are turned off. Therefore, an electrical path from the power source 220 to the ground of the B pole 643B and the C pole 643C through the A pole 643A is opened. At this time, as shown in FIG. 8B, a discharge current is generated from the A pole 643A toward the B pole 643B and the C pole 643C, and the current flows in the directions indicated by IA +, IB−, and IC− in FIG. Flowing.

  Note that the voltage Va at the drive terminal 240A in FIG. 4 is positive in the period P2 (see FIG. 7G). On the other hand, the voltage Vb of the drive terminal 240B is negative in the period P2 (see FIG. 7H). In addition, in the drive terminal 240C of FIG. 4, if the voltage flowing current in the IC + direction is a positive voltage and the voltage flowing current in the IC− direction is a negative voltage, the voltage Vc of the drive terminal 240C is negative in the period P2. (See FIG. 7 (i)). The interelectrode voltage VeAB is positive (see FIG. 7J), and the voltage VeCA between the electrode 643C and the electrode 643A (hereinafter referred to as “interelectrode voltage VeCA”) is negative (FIG. 7L). reference). The same applies to the periods P3 to P12.

  Thus, in the light source device 600 of the first embodiment, the voltage control unit 200 (FIG. 1) determines the interelectrode voltage VeAB based on the digital signals Ap to Cn output from the digital signal output unit 100 (FIG. 1). The voltage VeBC between the electrodes 643B and 643C (hereinafter referred to as “interelectrode voltage VeBC”) and the interelectrode voltage VeCA are controlled. Thereby, the discharge between the electrodes 643 is performed while sequentially repeating the twelve states shown in FIG. 8, and discharge light is generated. That is, the discharge tube 640 in the light source device 600 of the present embodiment has a plurality of light emitting portions (discharge gaps DG) arranged at positions near three vertices of a substantially equilateral triangle on a plane substantially perpendicular to the irradiation direction. (See FIG. 2B). Further, as shown in FIG. 8, in this embodiment, the discharge tube 640 is driven so that discharges in a plurality (two) of the discharge gaps DG occur simultaneously during a predetermined period (for example, P2 and P4). Is called. As the discharge state varies, the amount of discharge Lab between the electrode 643A and the electrode 643B (hereinafter referred to as “interelectrode discharge amount Lab”) and the amount of discharge Lbc between the electrode 643B and the electrode 643C (hereinafter referred to as “electrode discharge amount Lab”). , “Referred to as“ interelectrode discharge light quantity Lbc ”) and discharge light quantity Lca between the electrodes 643C and 643A (hereinafter referred to as“ interelectrode discharge light quantity Lca ”). It fluctuates as shown in (o).

  Here, the progress of the light emitted from the discharge tube 640 by the discharge between the electrodes 643 described above will be described with reference to FIG. As indicated by arrows in FIG. 1, the light emitted from the discharge tube 640 is reflected in at least one of the first reflecting surface RF1 and the second reflecting surface RF2, and then emitted toward the irradiation direction. .

  Specifically, light emitted from the discharge tube 640 and directly reaching the first reflecting surface RF1 is reflected by the first reflecting surface RF1 and emitted to the outside of the light source device 600. Here, since the first reflecting surface RF1 is formed in a concave curved shape facing the irradiation direction, the traveling direction of the reflected light on the first reflecting surface RF1 is approximately the irradiation direction.

  On the other hand, light emitted from the discharge tube 640 and directly reaching the second reflecting surface RF2 is reflected by the second reflecting surface RF2. Here, since the second reflecting surface RF2 is formed in a convex curved surface shape facing in the anti-irradiation direction, the concave reflecting surface shape in which the second reflecting surface RF2 faces in the anti-irradiation direction or a planar shape perpendicular to the anti-irradiation direction. Compared with the case where it is formed, the traveling direction of the reflected light on the second reflecting surface RF2 is a direction in which the light is more diffused. For this reason, the ratio of the light that returns to the vicinity of the discharge tube 640 after being reflected at the second reflecting surface RF2 is relatively small. Accordingly, most of the light reflected by the second reflecting surface RF2 reaches the first reflecting surface RF1 without affecting the discharge tube 640, is reflected, and is emitted to the outside of the light source device 600. Also in this case, the traveling direction of the reflected light on the first reflecting surface RF1 is approximately the irradiation direction.

  In addition, as shown in FIG. 1, the reflection direction of the light that has passed through the second reflection surface RF2 or directly reached the first reflection surface RF1 is not set parallel to the irradiation direction, and the light is centered. You may set in the direction which concentrates toward the predetermined | prescribed point on CA. In this case, by using the lens 620, the light traveling direction can be changed to the irradiation direction.

  As described above, in the light source device 600 according to the first embodiment, the ratio of the light emitted from the discharge tube 640 that is reflected by the second reflecting surface RF2 and returns to the vicinity of the discharge tube 640 again is compared. Less. Therefore, in the light source device 600 of the first embodiment, the loss of light due to the reflected light being converted into heat in the discharge tube 640 can be suppressed, and the light utilization efficiency can be improved. In other words, the ratio of effective light to power consumption is improved, and low power consumption can be realized. In addition, the illuminance can be improved. In addition, adverse effects due to light reflected in the direction returning to the vicinity of the discharge tube 640, for example, instability of the discharge state due to disturbance of the temperature characteristics of the discharge space 642 (FIG. 2A), or the electrode 643 (FIG. 2). It is possible to reduce the life of (a)) and the occurrence of light unevenness due to scattered light.

  Further, in the light source device 600 of the first embodiment, the discharge tube 640 has three light emitting units arranged in the vicinity of the three vertices of a substantially equilateral triangle on a virtual plane substantially perpendicular to the irradiation direction (FIG. 2). (See (b)). Therefore, the direction of the reflected light on the second reflecting surface RF2 is set to a direction that suppresses the diffusion as a whole, as compared with the conventional light source device having only one light emitting portion near the central axis CA. . That is, the diffusion of light is suppressed as long as the ratio of the light reflected by the second reflecting surface RF2 returns to the vicinity of the discharge tube 640 is reduced. Therefore, in the light source device 600 of the first embodiment, the light use efficiency can be improved.

  In the light source device 600 of this embodiment, as shown in FIG. 1, the light directly emitted from the discharge tube 640 and then directly reaches the second reflecting surface RF2 is as if it is located at a predetermined convergence point P. The position and shape of the second reflecting surface RF2 are set so as to be reflected in a direction as if emitted from a general substantially point light source. That is, the second reflecting surface RF2 is formed so that the reflected light on the second reflecting surface RF2 passes on a straight line connecting an arbitrary point on the second reflecting surface RF2 and the convergence point P. Therefore, in the light source device 600 of the present embodiment, a virtual substantially point light source located at the convergence point P can be formed, and the light utilization efficiency can be further improved. The straight line connecting the arbitrary point on the second reflecting surface RF2 and the convergence point P described above is an arbitrary point in the predetermined convergence space CS including the arbitrary point on the second reflecting surface RF2 and the convergence point P. It may be a straight line connecting points.

  Further, in the light source device 600 of the first embodiment, the discharge tube 640 has three light emitting portions arranged in the vicinity of three vertices of a substantially equilateral triangle on a virtual plane substantially perpendicular to the irradiation direction. The tube 640 may be a light source that is closer to a surface light source, and may be configured to emit light that is closer to parallel rays toward the second reflection unit 610. Therefore, the virtual substantially point light source located at the convergence point P can be made closer to the point light source, and the light use efficiency can be further improved.

  Further, the light source device 600 of the first embodiment is configured such that a plurality (two) of light emitting units emit light simultaneously during a predetermined period (for example, P2 and P4 in FIG. 8). Therefore, the discharge tube 640 can be configured to be a light source that is closer to a surface light source, and can emit light that is closer to a parallel light beam toward the second reflection unit 610. Therefore, the light use efficiency can be further improved.

  In the light source device 600 of the first embodiment, as can be seen from the voltages Va, Vb, and Vc (FIG. 7) of the drive terminals, the voltage having a frequency component, that is, a voltage that alternately repeats the lighting state and the non-lighting state. The voltage is applied to each electrode 643. However, as can be seen from the interelectrode voltages VeAB, VeBC, and VeCA in FIG. 7, discharge is always generated between at least one set of the electrodes 643 among the three electrodes 643 in all the periods (P1 to P12). . Therefore, a lighting state close to a direct current light source can be generated while a voltage having a frequency component is applied to each electrode 643. Thereby, for example, when the light source device 600 is applied to a projection display device using a liquid crystal panel, interference between the discharge frequency and the drive frequency of the liquid crystal panel can be reduced, and the occurrence of the flicker phenomenon can be suppressed.

  Further, in the light source device 600 of the first embodiment, the discharge is performed while repeating the state shown in FIG. 8 between the three electrodes 643, so that the variation in the discharge is alleviated and the luminance can be stabilized. In addition, since the discharge energy is distributed to the three electrodes 643, the life of the electrodes can be increased as compared with a conventional discharge tube having two electrodes. As can be seen from the interelectrode voltages VeAB, VeBC, and VeCA in FIG. 7, each electrode 643 is provided with a non-discharge region as a period in which no discharge occurs, so that the load on the electrode 643 can be further reduced.

  In the light source device 600 of the first embodiment, periods P5 and P11 in which both are at the L level are provided between the H level periods of the two digital signals Ap and An for the A pole (see FIG. 7). Therefore, there is no possibility that the two transistors 230Ap and 230An for the A pole in FIG. As a result, it is possible to prevent the voltage of the power source 220 from being applied to the transistors 230Ap and 230An and destroying the transistors 230Ap and 230An. The same applies to the transistors of the other electrodes 643.

  Furthermore, in the light source device 600 of the first embodiment, the energy is supplied to the electrode 643 based on the digital signals Ap to Cn, so that the control is simple. Further, since the drive control unit 1000 can be configured with a digital circuit, the circuit can be reduced in size. In this embodiment, there is one digital signal output unit 100, but one digital signal output unit 100 may be provided for each of the voltage control units 200A to 200C.

B. Second embodiment:
FIG. 9 is a timing chart when driving the light source device 600 in the second embodiment. FIG. 10 is an explanatory diagram conceptually showing the state of the discharge current formed between the electrodes in the second embodiment. In the second embodiment, the configuration of the light source device 600 (FIG. 1) is the same as that of the first embodiment, and only the driving mode is different from that of the first embodiment. FIG. 9 shows digital signals Ap to Cn output from the digital signal output unit 100 (FIG. 1) and voltage fluctuations accompanying fluctuations in the digital signals Ap to Cn, as in FIG. 7. Also, the reference symbols P1, P2,... Shown at the top of FIG. 9 represent the periods in the timing chart, and correspond to the reference symbols P1, P2,.

  For example, in the period P1 in the timing chart of FIG. 9, in the digital signal output unit 100 (FIG. 1), the three digital signals Ap, Bn, Cn are at the H level, and the other three digital signals An, Bp, Cp are An L level signal is output. At this time, in the circuit shown in FIG. 4, the three transistors 230Ap, 230Bn, and 230Cn are turned on, and the remaining three transistors 230An, 230Bp, and 230Cp are turned off. Therefore, an electrical path from the power source 220 to the ground of the B pole 643B and the C pole 643C through the A pole 643A is opened. At this time, as shown in FIG. 10A, a discharge current is generated from the A pole 643A toward the B pole 643B and the C pole 643C, and the current flows in the directions indicated by IA +, IB−, and IC− in FIG. Flowing.

  Similarly, in the period P2 in the timing chart of FIG. 9, the digital signal output unit 100 (FIG. 1) has the three digital signals An, Bp, and Cn at the H level, and the other three digital signals Ap, Bn, and Cp. Outputs an L level signal. At this time, in the circuit shown in FIG. 4, the three transistors 230An, 230Bp, and 230Cn are turned on, and the remaining three transistors 230Ap, 230Bn, and 230Cp are turned off. Therefore, an electrical path from the power source 220 to the ground of the A pole 643A and the C pole 643C through the B pole 643B is opened. At this time, as shown in FIG. 10B, a discharge current is generated from the B pole 643B toward the A pole 643A and the C pole 643C, and the current flows in the directions indicated by IA−, IB +, and IC− in FIG. Flowing. The same applies to the periods P3 to P6.

  Thus, also in the second embodiment, as in the first embodiment, the voltage control unit 200 (FIG. 1) is based on the digital signals Ap to Cn output from the digital signal output unit 100 (FIG. 1). The interelectrode voltage VeAB, the interelectrode voltage VeBC, and the interelectrode voltage VeCA are controlled. Thereby, the discharge between the electrodes 643 is performed while sequentially repeating the six states shown in FIG. 10, and discharge light is generated.

  Here, in the second embodiment, as can be seen from FIGS. 9 and 10, the discharge between the two sets of electrodes 643 is simultaneously performed in all the periods (P1 to P6). For example, in the period P1, discharge is performed between two sets of electrodes, that is, between the A pole and the B pole and between the A pole and the C pole. That is, the light source device 600 of the second embodiment is configured such that a plurality (two) of light emitting units emit light simultaneously over the entire driving period. Therefore, the discharge tube 640 can be configured to be a light source that is closer to a surface light source, and can emit light that is closer to a parallel light beam toward the second reflection unit 610. Therefore, the virtual substantially point light source located at the convergence point P can be made closer to the point light source, and the light use efficiency can be further improved.

C. Third embodiment:
FIG. 11 is an explanatory diagram schematically showing the configuration of the light source device 600a of the third embodiment. FIG. 11A shows a cross section parallel to the irradiation direction of the light source device 600a, and FIG. 11B shows a bb cross section of FIG. 11A. As shown in FIG. 11, the light source device 600a of the third embodiment is provided with an LED light source 680 as a light source section instead of the discharge tube 640 (FIG. 1) in the first embodiment. This is different from the light source device 600 of the example.

  In the light source device 600a of the third embodiment, the LED light source 680 is supported by the base portion 650 of the first reflecting portion 660. The LED light source 680 is connected to a circuit board 682, a plurality of LED light emitting units 681 disposed on the circuit board 682, a conductive material 683 for supplying power to the circuit board 682, and an end of the conductive material 683. Electrode terminal 684. In this embodiment, as shown in FIG. 11B, four LED light emitting portions 681 are arranged symmetrically about a central axis CA on a substantially disc-shaped circuit board 682, and each LED light emitting portion 681 is arranged. Is provided with a plurality of LED elements. The LED light source 680 further includes a heat conducting member 685 and a heat dissipating material 686 in order to release heat generated in the LED light emitting unit 681 and the circuit board 682.

  The LED light source 680 is connected to the drive control unit 1000a via the power line 810. The drive control unit 1000a controls switching of turning on and off of the LED light source 680. The drive control unit 1000a can turn on the LED elements on all the LED light emitting units 681, or can turn on some of the LED elements. The LED light source 680 functions as a substantial surface light source.

  In the light source device 600a of the third embodiment, similarly to the first embodiment, the light emitted from the LED light source 680 is reflected by at least one of the first reflecting surface RF1 and the second reflecting surface RF2. Later, it is emitted in the direction of irradiation. Specifically, light emitted from the LED light source 680 and directly reaching the first reflection surface RF1 is reflected by the first reflection surface RF1 and emitted to the outside of the light source device 600a. On the other hand, light emitted from the LED light source 680 and directly reaching the second reflecting surface RF2 is reflected on the second reflecting surface RF2 in a relatively diffusing direction. Thereafter, most of the light reflected by the second reflection surface RF2 reaches the first reflection surface RF1 without affecting the LED light source 680, is reflected, and is emitted to the outside of the light source device 600a.

  As described above, in the light source device 600a of the third embodiment, similar to the light source device 600 of the first embodiment, the light emitted from the LED light source 680 is reflected on the second reflecting surface RF2 and then again. The proportion of light returning to the vicinity of the LED light source 680 is relatively small. Therefore, in the light source device 600a of the third embodiment, the loss of light due to the reflected light being converted into heat in the LED light source 680 can be suppressed, and the light utilization efficiency can be improved. Further, adverse effects due to light reflected in the direction returning to the vicinity of the LED light source 680, for example, shortening of the life of the LED light emitting portion 681 and the circuit board 682, occurrence of light unevenness due to scattered light, and the like can be reduced.

  Also in the light source device 600a of the third embodiment, the LED light source 680 has a plurality of light emitting units (LED elements) at a plurality of positions on a virtual plane substantially perpendicular to the irradiation direction (see FIG. 11B). ). Therefore, the direction of the reflected light on the second reflecting surface RF2 is set to a direction that suppresses the diffusion as a whole, as compared with the conventional light source device having only one light emitting portion near the central axis CA. . Therefore, the light use efficiency can be improved also in the light source device 600a of the third embodiment.

  In addition, since the light source device 600a of the third embodiment includes the LED light source 680 that functions as a substantial surface light source as a light source unit, light closer to parallel light can be emitted toward the second reflecting unit 610. Therefore, the virtual substantially point light source located at the convergence point P can be made closer to the point light source, and the light use efficiency can be further improved.

D. Fourth embodiment:
FIG. 12 is an explanatory diagram schematically showing the configuration of the light source device 600b of the fourth embodiment. 12A shows a cross section parallel to the irradiation direction of the light source device 600b, and FIG. 12B shows a bb cross section of FIG. 12A. As shown in FIG. 12, the light source device 600b of the fourth embodiment is provided with an EL light source 690 instead of the LED light source 680 (FIG. 11) in the third embodiment as a light source section. This is different from the light source device 600a of the example.

  In the light source device 600b of the fourth embodiment, the EL light source 690 includes a circuit board 692, an EL light emitting unit 691 disposed on the circuit board 692, a conductive material 693 for supplying power to the circuit board 692, and a conductive material. And an electrode terminal 694 connected to an end portion of the material 693. In this embodiment, as shown in FIG. 12B, a circular EL light emitting portion 691 is arranged around a central axis CA on a substantially disc-shaped circuit board 692, and the EL light emitting portion 691 includes A plurality of EL elements are provided. The EL light source 690 further includes a heat conducting member 695 and a heat dissipating material 696 in order to release heat generated in the EL light emitting unit 691 and the circuit board 692. The EL light source 690 is connected to the drive control unit 1000b via the power line 810. The drive control unit 1000b controls switching of turning on and off of the EL light source 690. The EL light source 690 functions as a substantial surface light source.

  In the light source device 600b of the fourth embodiment, similarly to the third embodiment, the light emitted from the EL light source 690 is reflected by at least one of the first reflecting surface RF1 and the second reflecting surface RF2. Later, it is emitted in the direction of irradiation. Specifically, light emitted from the EL light source 690 and directly reaching the first reflection surface RF1 is reflected by the first reflection surface RF1 and emitted to the outside of the light source device 600b. On the other hand, light emitted from the EL light source 690 and directly reaching the second reflecting surface RF2 is reflected on the second reflecting surface RF2 in a relatively diffusing direction. Thereafter, most of the light reflected by the second reflecting surface RF2 reaches the first reflecting surface RF1 without affecting the EL light source 690, is reflected, and is emitted to the outside of the light source device 600b.

  As described above, in the light source device 600b of the fourth embodiment, similar to the light source device 600a of the third embodiment, the light emitted from the EL light source 690 is reflected on the second reflecting surface RF2 and then again. The ratio of light returning to the vicinity of the EL light source 690 is relatively small. Therefore, in the light source device 600b of the fourth embodiment, the loss of light due to the reflected light being converted into heat in the EL light source 690 can be suppressed, and the light utilization efficiency can be improved. In addition, adverse effects due to light reflected in the direction returning to the vicinity of the EL light source 690, such as shortening of the lifetime of the EL light emitting portion 691 and the circuit board 692, occurrence of light unevenness due to scattered light, and the like can be reduced.

  Also in the light source device 600b of the fourth embodiment, the EL light source 690 has a plurality of light emitting portions (EL elements) at a plurality of positions on a virtual plane substantially perpendicular to the irradiation direction (see FIG. 12B). ). Therefore, the direction of the reflected light on the second reflecting surface RF2 is set to a direction that suppresses the diffusion as a whole, as compared with the conventional light source device having only one light emitting portion near the central axis CA. . Therefore, the light use efficiency can be improved also in the light source device 600b of the fourth embodiment.

  Further, since the light source device 600b of the fourth embodiment includes the EL light source 690 that functions as a substantial surface light source as the light source unit, light closer to parallel light can be emitted toward the second reflecting unit 610. Therefore, the virtual substantially point light source located at the convergence point P can be made closer to the point light source, and the light use efficiency can be further improved.

E. Variation:
The present invention is not limited to the above-described examples and embodiments, and can be implemented in various modes without departing from the gist thereof. For example, the following modifications are possible.

E-1. Modification 1:
The configuration of the light source device 600 in each of the above embodiments is merely an example, and other configurations can be adopted. For example, in each of the above embodiments, the discharge tube 640, the LED light source 680, and the EL light source 690 are employed as the light source units, but other light sources may be employed as the light source units. In each of the above embodiments, the second reflecting surface RF2 of the second reflecting portion 610 may have another convex shape as long as the second reflecting surface RF2 is formed in a convex curved shape facing the anti-irradiation direction. is there.

E-2. Modification 2:
In the first embodiment described above, the discharge tube 640 of the light source device 600 has been described as being driven by a three-phase drive circuit. However, the discharge tube 640 is driven by a two-phase drive circuit or a four-phase or more multi-phase drive circuit. It is good. Further, the number of electrodes 643 and other elements corresponding to the electrodes 643 of the discharge tube 640 can be arbitrarily set depending on the drive circuit used.

E-3. Modification 3:
In the first embodiment, the arrangement of the electrode 643 of the discharge tube 640 is a delta type, but the arrangement of the electrode 643 of the discharge tube 640 may be a star type. At this time, in addition to the three electrodes (A pole, B pole, C pole) shown in FIG. 3, a COM pole (common) is provided, and discharge is performed between the A pole, the B pole, the C pole, and the COM pole. It becomes the composition like this.

It is explanatory drawing which shows roughly the structure of the light source device 600 as 1st Example of this invention. It is explanatory drawing which shows the detailed structure of the discharge tube 640 in 1st Example. It is a conceptual diagram of the electrode 643 in the discharge tube 640 of 1st Example. 3 is an explanatory diagram showing a configuration of a voltage control unit 200 in a drive control unit 1000. FIG. 3 is an explanatory diagram showing a configuration of a booster 250. FIG. FIG. 11 is an explanatory diagram showing another configuration of the booster 250. It is a timing chart at the time of driving the light source device 600 of 1st Example. It is explanatory drawing which shows notionally the mode of the discharge current formed between each electrode. It is a timing chart at the time of driving the light source device 600 in 2nd Example. It is explanatory drawing which shows notionally the mode of the discharge current formed between each electrode in 2nd Example. It is explanatory drawing which shows schematically the structure of the light source device 600a of 3rd Example. It is explanatory drawing which shows schematically the structure of the light source device 600b of 4th Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Digital signal output part 200 ... Voltage control part 210 ... Level shifter 220 ... Power supply 230 ... Switching transistor 240 ... Drive terminal 250 ... Boosting part 600 ... Light source device 610 ... 2nd reflection part 620 ... Lens 640 ... Discharge tube 641 ... Discharge vessel 642 ... Discharge space 643 ... Electrode 644 ... Branch part 645 ... Body part 646 ... Metal foil 647 ... Electrode terminal 650 ... Base part 660 ... First reflection part 662 ... Cover 670 ... Hollow part 680 ... LED light source 681 ... LED light emitting part 682 ... Circuit board 683 ... Conductive material 684 ... Electrode terminal 685 ... Heat conduction member 686 ... Heat radiation material 690 ... EL light source 691 ... EL light emitting part 692 ... Circuit board 693 ... Conductive material 694 ... Electrode terminal 695 ... Heat conduction member 696 ... Heat radiation material 810 ... Power supply line 1000 ... Drive control unit

Claims (5)

A light source device,
A light source unit having light emitting units arranged at a plurality of positions on a first virtual plane substantially orthogonal to the irradiation direction of the light source device;
A first concave reflection surface having a first reflection surface having a shape that forms a boundary of a space including the light emitting portion together with a second virtual plane substantially orthogonal to the irradiation direction of the light source device. The reflective part of
A second reflecting portion that is located on the irradiation direction side with respect to the light emitting portion in the space and has a second reflecting surface having a convex curved shape that faces in a direction opposite to the irradiation direction. Light source device. The light source device according to claim 1,
The light source unit and the second reflection unit are configured so that a virtual substantially point light source is formed at a position closer to the irradiation direction than the second reflection surface. The light source device according to claim 1,
For each of the plurality of light emitting units, the second reflecting surface is configured such that reflected light emitted from the light emitting unit and directly reflected by the second reflecting surface is an arbitrary point on the second reflecting surface, and A light source device in which a position and a shape are set so as to pass on a straight line connecting a predetermined convergence point located on the irradiation direction side from the second reflecting surface. The light source device according to any one of claims 2 and 3,
The light source unit is a light source device configured such that the light emitting units at a plurality of positions can emit light simultaneously.   A projection display device comprising the light source device according to any one of claims 1 to 4.

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