JP5757176B2 - Light source device and projector - Google Patents

Description

  The present invention relates to a light source device and a projector.

  As a light source device for a projector, a light source device described in Patent Document 1 is known. The light source device disclosed in Patent Document 1 forms a phosphor layer on a rotatable substrate, and obtains light having a desired wavelength by exciting the phosphor layer with an excitation light source while rotating the substrate. In the light source device of Patent Document 1, since the phosphor layer is provided on a rotatable substrate, even if the phosphor layer is heated by irradiating excitation light to a portion corresponding to the condensing spot of the phosphor layer. The spot is immediately removed from the focused spot and is then cooled by ambient air until the excitation light is applied. Therefore, compared with the case where excitation light is continuously irradiated to a specific location, the temperature rise of the phosphor layer is suppressed, and the phosphor layer is hardly deteriorated and the wavelength conversion efficiency of the phosphor layer is less likely to occur.

JP 2009-277516 A

  In the light source device of Patent Document 1, since the substrate is rotated, the portion irradiated with the excitation light in a certain round is surrounded by the period before the excitation light is irradiated in the next round (after one rotation period has elapsed). Cooled by air. However, the region of the phosphor layer that is irradiated with the excitation light is the same in each turn. That is, since the excitation light is repeatedly irradiated to the specific portion of the phosphor layer at short time intervals for each turn, the portion is not sufficiently cooled, and the temperature rise of the phosphor layer cannot be sufficiently suppressed. As a result, the phosphor layer deteriorates and the wavelength conversion efficiency of the phosphor layer decreases.

  An object of the present invention is to provide a light source device and a projector that suppresses a temperature rise of a phosphor layer and hardly causes deterioration of the phosphor layer and a decrease in wavelength conversion efficiency of the phosphor layer.

A light source device of the present invention includes a substrate that includes a phosphor layer and is rotatable around a predetermined rotation axis, a light source that intermittently emits excitation light that excites the phosphor layer, and the substrate rotates. The first region of the phosphor layer is irradiated with the excitation light in one round, and at least some of the first region is irradiated with the excitation light in another round. A rotation period determining device that controls the rotation of the substrate so that the phosphor layer is divided into a plurality of segments along the rotation direction of the substrate. The integrated light amount of the excitation light irradiated to the first segment among the plurality of segments of the excitation light irradiated to the second segment different from the first segment among the plurality of segments per unit time Integrated light intensity Equal.

  According to this structure, the area | region where the excitation light of a fluorescent substance layer is irradiated differs mutually by one round and another round. Therefore, compared with the case where the region of the phosphor layer irradiated with the excitation light is always the same every round, the phosphor layer has a higher cooling effect and the temperature rise of the phosphor layer is smaller. Therefore, a light source device is provided in which deterioration of the phosphor layer and decrease in wavelength conversion efficiency of the phosphor layer are unlikely to occur.

  The rotation period determining device includes a region in the phosphor layer that is irradiated with the excitation light during the rotation of the phosphor layer and the other rotation of the phosphor layer when the substrate is rotating. You may control rotation of the said board | substrate so that the area | region irradiated with excitation light may not mutually overlap. In addition, the rotation period determining device may include a region in the phosphor layer that is not irradiated with the excitation light during the rotation of the substrate and the other rotation of the phosphor layer when the substrate is rotating. You may control rotation of the said board | substrate so that the area | region which is not irradiated with the said excitation light may not mutually overlap.

  According to this configuration, the position where the excitation light of the phosphor layer is irradiated can be reliably dispersed along the rotation direction of the substrate in one round and the other round.

  When the phosphor layer is divided into a plurality of segments along the rotation direction of the substrate, the integrated light amount of the excitation light irradiated to the first segment among the plurality of segments per unit time is the unit time. Of course, the integrated light quantity of the excitation light applied to a second segment different from the first segment among the plurality of segments may be equal.

  According to this configuration, it is possible to suppress the degree of deterioration of the phosphor layer and the variation in wavelength conversion efficiency of the phosphor layer from segment to segment. Therefore, a light source device that has a long lifetime and is unlikely to change in brightness when lit is provided. In this case, such an effect is the greatest if the integrated light amounts of the excitation light irradiated per unit time are equal in all segments.

  The other round may be a round next to the one round.

  According to this configuration, the position where the excitation light of the phosphor layer is irradiated can be reliably dispersed along the rotation direction of the substrate by one round and the next round.

  The light emission timing signal for controlling the light emission timing of the light source further includes a light emission timing generation device that generates a light emission timing signal having a period synchronized with a frame period, and the rotation period determination device includes the rotation period of the substrate as the rotation period of the substrate, A rotation period that is a non-integer multiple of the period of the light emission timing signal may be determined.

  According to this structure, the position where the excitation light of the phosphor layer is irradiated every round can be reliably dispersed along the rotation direction of the substrate.

  The rotation period determining device may determine a period of (1 + δ) times the period of the light emission timing signal as a rotation period of the substrate, with a duty of a light emission period of the light source being δ (0 <δ <1). .

  According to this configuration, the least common multiple of the rotation period of the rotating fluorescent plate and the light emission period of the light source can be set as one unit time, and the irradiation position of the excitation light can be periodically changed every unit time. Further, when the phosphor is divided into a plurality of segments along the rotation direction of the substrate, the integrated light amounts of the excitation light irradiated per unit time can be made equal in all the segments.

  The duty δ may be 0.5 or less.

  According to this configuration, since the region irradiated with the excitation light in a certain round does not overlap with the region irradiated with the excitation light in the next round, the temperature rise of the phosphor layer is effectively suppressed. .

  The light source device of the present invention includes a substrate that includes a phosphor layer and is rotatable around a predetermined rotation axis, a light source that intermittently emits excitation light that excites the phosphor layer, and the rotation of the substrate is the When the phosphor layer is divided into a plurality of segments along the rotation direction of the substrate so as to be asynchronous with the emission of the excitation light, the first segment among the plurality of segments per unit time. The integrated light amount of the excitation light irradiated is equal to the integrated light amount of the excitation light irradiated to a second segment different from the first segment among the plurality of segments per unit time. A rotation period determining device for controlling the rotation of the substrate.

  According to this structure, the area | region where the excitation light of a fluorescent substance layer is irradiated differs mutually by one round and another round. Therefore, compared with the case where the region of the phosphor layer irradiated with the excitation light is always the same every round, the phosphor layer has a higher cooling effect and the temperature rise of the phosphor layer is smaller. Therefore, a light source device is provided in which deterioration of the phosphor layer and decrease in wavelength conversion efficiency of the phosphor layer are unlikely to occur. Furthermore, it is possible to suppress the degree of deterioration of the phosphor layer and the variation in wavelength conversion efficiency of the phosphor layer from segment to segment. Therefore, a light source device that has a long lifetime and is unlikely to change in brightness when lit is provided.

  In all the segments, the integrated light amounts of the excitation light irradiated per unit time may be equal to each other.

  According to this configuration, it is possible to enhance the effect of suppressing the degree of deterioration of the phosphor layer and the variation in wavelength conversion efficiency of the phosphor layer from segment to segment.

  The projector of the present invention includes a light source device of the present invention, a light modulation element that modulates the fluorescence emitted from the light source device with an image signal, and a projection optical system that projects the fluorescence modulated by the light modulation element. It is equipped with.

  According to this configuration, it is possible to provide a projector in which the phosphor layer is hardly deteriorated and the wavelength conversion efficiency of the phosphor layer is hardly reduced.

It is the schematic of the projector of 1st Embodiment. It is a block diagram which shows the function structure of the control system which controls operation | movement of a projector. It is the figure which divided | segmented the fluorescent substance into several segments along the rotation direction of a rotation fluorescent plate. It is a figure which shows the relationship between the rotation period of a rotation fluorescent plate, and the light emission timing of a light source. It is the figure which showed the segment irradiated with excitation light in time series for every round. It is a flowchart which shows the procedure of the process which the control system of a projector performs. It is the figure which divided | segmented the fluorescent substance into several segments along the rotation direction of a rotation fluorescent plate in the projector of 2nd Embodiment. It is a figure which shows the relationship between the rotation period of a rotation fluorescent plate, and the light emission timing of a light source. It is the figure which showed the segment irradiated with excitation light in time series for every round. It is the schematic of the projector of 3rd Embodiment. It is a block diagram which shows the function structure of the control system which controls operation | movement of a projector. It is the figure which divided | segmented the fluorescent substance into several segments along the rotation direction of a rotation fluorescent plate. It is a figure which shows the relationship between the rotation period of a rotation fluorescent plate, and the light emission timing of a light source. It is the figure which showed the segment irradiated with excitation light in time series for every round. It is a figure which shows the relationship between the rotation period of a rotation fluorescent plate, and the light emission timing of a light source. It is the figure which showed the segment irradiated with excitation light in time series for every round.

[First Embodiment]
FIG. 1 is a schematic diagram of a projector 1 according to the first embodiment.

  The projector 1 includes a red light source device 10R, a green light source device 10G, a blue light source device 10B, a red liquid crystal display element 30R, a green liquid crystal display element 30G, a blue liquid crystal display element 30B, and a color. A synthesis optical system 40 and a projection optical system 50 are provided.

  The green light source device 10G includes a light source 11, a condensing lens 12a, a collimating lens 12b, a rotating fluorescent plate 13, a motor 14, a pickup optical system 15, a dichroic mirror 16, a condensing lens 17, and a rod integrator. 18 and a collimating lens 19.

  The light source 11 is a solid light source array in which optical elements each having a set of a solid light source 35 and a collimating lens 36 that collimates the light emitted from the solid light source 35 are arranged in a 5 × 5 two-dimensional array. . As the solid light source 35, for example, a semiconductor laser element (Laser Diode; LD) that emits blue laser light as excitation light is used. Excitation light has a characteristic that a peak of emission intensity appears at a wavelength of about 450 nm, for example.

  The excitation light emitted from the light source 11 is once narrowed by the condenser lens 12a and the collimating lens 12b. Thereafter, the optical path is bent 90 degrees by the dichroic mirror 16, and the light is condensed on the phosphor 13 b of the rotating fluorescent plate 13 by the pickup optical system 15. The excitation light incident on the phosphor 13b has a substantially square shape of □ 1 mm over the entire focused spot.

  The rotating fluorescent plate 13 is formed by continuously forming a phosphor 13b as a phosphor layer on one surface of a disc 13a as a substrate along the circumferential direction of the disc 13a. The rotating fluorescent plate 13 is rotatably supported by a motor 14 and converts the excitation light collected by the pickup optical system 15 into green fluorescence (hereinafter sometimes simply referred to as green light) and emits it.

  The disc 13a is formed of a metal substrate such as an aluminum substrate, for example. The surface of the disk 13a on which the phosphor 13b is formed is a reflecting surface that reflects the green light emitted from the phosphor 13b. A hole through which the rotation axis Ax of the motor 14 passes is formed in the center of the circle of the disk 13a. In addition, although the example using the disk 13a as a board | substrate was demonstrated here, the shape of a board | substrate is not limited to a disk, What is necessary is just a flat plate.

  The phosphor 13b is formed by applying a green phosphor on the disc 13a in a state of being mixed in a transparent resin. As the green phosphor, for example, β sialon (Si, Al) 6 (O, N) 8: Eu, silicate system (Ca 3 Sc 2 Si 3 O 12: Ce) or the like can be used. Various other green phosphors exist, but any may be used. The transparent resin is a silicone resin, which is kneaded with a green phosphor powder, coated, thermally cured, and fixed on the disk 13a. The circular plate 13a also serves as a heat radiating plate for efficiently radiating the heat generated in the phosphor.

  The rotating fluorescent plate 13 is provided with the surface on which the phosphor 13b is formed facing the side on which the excitation light is incident so that the excitation light emitted from the light source 11 is incident on the phosphor 13b from the side opposite to the disc 13a. It has been.

  The motor 14 is an electric motor that rotates the rotating fluorescent plate 13. The motor 14 takes in a rotation instruction signal supplied from a motor driving unit, which will be described later, and rotates the rotation axis Ax at a rotation cycle corresponding to the rotation instruction signal. The motor 14 includes a position detection sensor realized by, for example, a Hall element, and outputs position information indicating a reference position of the rotation axis Ax detected by the position detection sensor.

  The pickup optical system 15 includes a single lens or a plurality of lenses, for example, a first lens 15a and a second lens 15b. The pickup optical system 15 condenses excitation light emitted from the light source 11 on the phosphor 13b and also emits fluorescence. The green light emitted from the body 13b is made substantially parallel.

  The dichroic mirror 16 is a wavelength selective transmission / reflection member that reflects the excitation light emitted from the light source 11 and transmits the green light emitted from the phosphor 13b. The green light emitted from the fluorescent body 13 b is substantially collimated by the pickup optical system 15, and after the residual excitation light is removed by the dichroic mirror 16, it is re-condensed by the condenser lens 17 and passes through the rod integrator 18. .

  The rod integrator 18 is a prismatic optical member that extends in the optical path direction. In the rod integrator 18, light is mixed and made uniform by multiple reflection. The green light emitted from the rod integrator 18 is substantially collimated by the collimating lens 19 and enters the green liquid crystal display element 30G as a light modulation element.

  The red light source device 10 </ b> R includes a light source 20, a rod integrator 21, a collimator lens 22, and a reflection mirror 23.

  As the light source 20, for example, a light emitting diode (LED) that emits red light is used. For example, red light has a characteristic in which a peak of emission intensity appears at a wavelength of about 600 nm. The red light emitted from the light source 20 is made uniform in luminance by the rod integrator 21 and then substantially collimated by the collimator lens 22, and passes through the reflection mirror 23 to the red liquid crystal display element 30 </ b> R as a light modulation element. Incident.

  The blue light source device 10 </ b> B includes a light source 24, a rod integrator 25, a collimator lens 26, and a reflection mirror 27.

  As the light source 24, for example, a light emitting diode (LED) that emits blue light is used. For example, blue light has a characteristic in which a peak of emission intensity appears at a wavelength of about 450 nm. The blue light emitted from the light source 24 is made uniform in luminance by the rod integrator 25 and then substantially collimated by the collimator lens 26, and is passed through the reflection mirror 27 to the blue liquid crystal display element 30B as a light modulation element. Incident.

  The red liquid crystal display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B are transmissive light modulation elements in which polarizing plates are attached to both surfaces (light incident surface and light emission surface) of the liquid crystal panel. . The red liquid crystal display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B are red light, green light, and blue light incident from the red light source device 10R, the green light source device 10G, and the blue light source device 10B. Are modulated based on an image signal supplied from the outside to generate red image light, green image light, and blue image light.

  The color combining optical system 40 combines the red image light, the green image light, and the blue image light generated by the red liquid crystal display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B. This is a cross dichroic prism that forms color image light of the three primary colors. The cross dichroic prism is an optical member formed by bonding four right-angle prisms into a cube. A dielectric multilayer film is formed on the X-shaped interface where the right-angle prisms are bonded together. The dielectric multilayer film formed on one X-shaped interface reflects red light, and the dielectric multilayer film formed on the other interface reflects blue light. The cross dichroic prism aligns the traveling direction of red light and blue light whose traveling direction has been changed by these dielectric multilayers respectively with the transmitting green light, thereby red image light, green image light and blue image. Synthesize light.

  The red image light, the green image light, and the blue image light synthesized by the color synthesis optical system 40 are enlarged and projected on the screen SCR by the projection optical system 50 and recognized as a color image by the user.

  In the present embodiment, the projector 1 is a projector that displays a 3D image. The red liquid crystal display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B alternately generate right-eye images and left-eye images. The user observes the right-eye image and the left-eye image projected on the screen SCR using shutter-type 3D glasses.

  In the 3D glasses, in the red liquid crystal display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B, the liquid crystal is aligned from the right eye image to the left eye image or from the left eye image to the right eye image. During the transition period until switching, the shutters of both eyes are turned off. Then, the shutter of the right eye or the left eye is turned on when the liquid crystal orientation is completely switched. By doing so, display defects (crosstalk) due to the mixture of the right-eye image and the left-eye image are reduced.

  During the transition period until the alignment of the liquid crystal is completely switched, the shutters of both eyes are turned off. Therefore, in the red light source device 10R, the green light source device 10G, and the blue light source device 10B, the output light amount in the transition period is set to zero (non-light emission) in order to reduce power consumption. Therefore, in the red light source device 10R, the green light source device 10G, and the blue light source device 10B, intermittent light emission in which the transient period is off and the non-transient period is on is performed.

  FIG. 2 is a block diagram illustrating a functional configuration of a control system that controls the operation of the projector 1. In FIG. 2, only the configuration necessary for drive control of the light source 11, which is a characteristic part of the present invention, is extracted and simplified from the configuration illustrated in FIG. 1.

  The projector 1 includes a control unit (control device) 61, a light source driving unit 62, a motor driving unit 63, and an image signal supply unit 64 as a control system.

  The control unit 61 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory) (all of which are not shown). The CPU reads the control program stored in the ROM, expands it in the RAM, and executes the program steps on the RAM. The control unit 61 controls the overall operation of the projector 1 by executing the program by the CPU. The control unit 61 supplies an image output request signal to the image signal supply unit 64 by executing the control program.

  The control unit 61 includes a light emission timing generation unit 101 as a light emission timing generation device and a rotation cycle determination unit 102 as a rotation cycle determination device as functional configurations.

  The light emission timing generation unit 101 captures the frame synchronization signal supplied from the image signal supply unit 64, and determines the emission period of the excitation light emitted from the light source 11, the red light emitted from the light source 20, and the blue light emitted from the light source 24. A light emission timing signal for control is generated in synchronization with the frame synchronization signal, and the light emission timing signal is supplied to the light source driving unit 62 and the rotation period determining unit 102.

  The frame synchronization signal is a synchronization signal that determines the frame period of the video, and is, for example, a pulse signal having a frame rate of 60 frames / second (fps). The light emission timing signal is, for example, a positive active pulse signal synchronized with the frame synchronization signal as described above.

  In the present embodiment, one frame period is divided into two subframes, and a right eye image and a left eye image are displayed for each subframe. The light source 11, the light source 20, and the light source 24 emit light once every subframe in accordance with the display timing of the right eye image and the left eye image. Therefore, when the frame rate of the frame synchronization signal is 60 fps, the light emission timing signal is a positive active pulse signal having a period of 1/120 second synchronized with the frame period.

  The rotation cycle determination unit 102 takes in the light emission timing signal supplied from the light emission timing generation unit 101, calculates the rotation cycle of the rotating fluorescent screen 13 that is asynchronous with the pulse cycle of the light emission timing signal, and the value of this rotation cycle (rotation). (Period value) is supplied to the motor drive unit 63. When the rotating fluorescent plate 13 is rotating, the rotation period determining unit 102 irradiates the first region of the phosphor 13b with excitation light in one rotation, and at least a part of the first region. The rotation period is not an integral multiple of the pulse period of the light emission timing signal (non-integer multiple) and is not an integral fraction (one non-integer fraction) so that the region is not irradiated with excitation light in the next round. A value is obtained, and this rotation period value is supplied to the motor drive unit 63.

  Further, the rotation cycle determination unit 102 takes in the position information of the rotation axis Ax of the motor 14 supplied from the motor driving unit 63 and determines whether or not the rotation axis Ax of the motor 14 is rotating based on this position information. To do.

  The light source drive unit 62 takes in the light emission timing signal supplied from the light emission timing generation unit 101 of the control unit 61, and causes the light source 11, the light source 20, and the light source 24 to emit light intermittently based on the timing indicated by the light emission timing signal. That is, when the light emission timing signal is a positive active pulse signal, the light source driving unit 62 causes the light source 11, the light source 20, and the light source 24 to emit light during the positive period of the light emission timing signal. In the present embodiment, the level value of the excitation light emitted from the light source 11 is constant.

  The motor drive unit 63 takes in the rotation cycle value supplied from the rotation cycle determination unit 102 of the control unit 61, generates a rotation instruction signal designating this rotation cycle value, supplies the rotation instruction signal to the motor 14, and drives it. Further, the motor drive unit 63 takes in the position information of the rotation axis Ax supplied from the motor 14 and supplies the position information to the rotation cycle determination unit 102.

  The image signal supply unit 64 includes a synchronization signal generation unit (not shown), and supplies the frame synchronization signal generated by the synchronization signal generation unit to the light emission timing generation unit 101 of the control unit 61. Further, the image signal supply unit 64 takes in the image output request signal supplied from the control unit 61, and synchronizes the image signal supplied from the outside with the frame synchronization signal in response to the image output request signal. This is supplied to the display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B.

  FIG. 3 is a diagram in which the phosphor 13b is virtually divided into a plurality of segments (fan-shaped regions around the rotation axis) along the rotation direction of the rotating fluorescent plate 13. Note that the division into segments is for convenience of explanation and is not actually divided. FIG. 4 is a diagram showing the relationship between the rotation period of the rotating fluorescent plate 13 and the light emission timing of the light source 11. FIG. 5 is a diagram showing the segments (light-emitting segments) irradiated with the excitation light in time series for each round. In FIG. 5, “◯” indicates that the light source emits light, and “X” indicates that the light source does not emit light.

  As shown in FIG. 3, in the rotating fluorescent plate 13 of the present embodiment, the phosphor 13 b is virtually divided into three segments (segment A to segment C) along the rotating direction of the rotating fluorescent plate 13. The light source 11 is repeatedly turned on / off at a constant time interval, and the excitation light is intermittently applied to the condensed spot 70 on the phosphor 13b at a constant time interval. Since the rotating fluorescent plate 13 rotates around the rotation axis Ax, the condensed spot 70 moves around the rotation axis Ax on the phosphor 13b. Since the light source 11 is repeatedly turned on / off at regular time intervals, a fan-shaped region corresponding to the locus drawn by the condensed spot 70 while the light source 11 is turned on once is defined as one virtual segment. For example, when the segment A overlaps with the condensing spot 70, if the light source 11 emits light and the segment A is irradiated with the excitation light 70, the segment A is called a light emitting segment, and the segment A overlaps with the condensing spot 70. When the light source 11 does not emit light and the segment A is not irradiated with the excitation light 70, the segment A is called a non-light-emitting segment.

  In the present embodiment, as will be described later, a period during which the light source 11 is on (light emission period) and a period during which the light source 11 is off (non-light emission period) are equal to each other, and the duty of the light emission period is 50%. Therefore, as the rotating fluorescent plate 13 rotates, one segment is made a light emitting segment, and then the adjacent segment is made a non-light emitting segment. However, the central angles of the individual segments are equal to each other. The duty of the light emission period is calculated as light emission period / (light emission period + non-light emission period).

  As shown in FIG. 4, in the present embodiment, the 3D glasses are switched at 120 Hz, and the duty of the opening period (the period in which the user visually recognizes the image by transmitting the image light) is 50%. The light emission period of the phosphor 13b (light emission period of the light source 11) is 120 Hz and the duty is 50% (light emission period 4.2 ms) in accordance with the 3D glasses. Therefore, the rotational speed of the rotating fluorescent plate 13 is, for example, 80 Hz (rotation period is 12 Hz). .5 ms).

  The rotational speed of the rotating fluorescent plate 13 is calculated as α (Hz) × β, where α (Hz) is the emission frequency (switching frequency of the 3D glasses) when the light source is intermittently emitted and β is the adjustment coefficient. The adjustment coefficient β is calculated by β = 1 / (1 + δ), where δ is the duty of the light emission period of the light source 11. Since the rotation period of the rotating fluorescent plate 13 is the reciprocal of the rotation number, the rotation period of the rotating fluorescent plate 13 is (1 + δ) times the light emission period (1 / α) of the light source 11. Since the duty δ is 0 <δ <1, the rotation period of the rotating fluorescent plate 13 is a non-integer multiple of the light emission period of the light source 11.

  As shown in FIG. 5, in the first cycle of light emission of the phosphor 13b (light source 11), the segment A in FIG. 3 is irradiated with the excitation light 70, and in the second cycle, the segment C is irradiated with the excitation light 70, and the third cycle. The eyes are irradiated with the excitation light 70 on the segment B, and the excitation light 70 is irradiated again on the segment A in the fourth cycle. When viewed from the rotation of the rotating fluorescent plate 13, the excitation light 70 is irradiated to the segment A and the segment C in the first round (period T1), and the excitation light 70 is irradiated to the segment B in the second round (period T2). In the round (period T3), the segment 70 and the segment C are irradiated with the excitation light 70 again. In this way, in the third round following the second round (period T2), the first round (period T1) is resumed, and two cycles consisting of the period T1 and the period T2 are repeated. Thus, excitation light is irradiated to a different segment for every round.

  In this configuration, since the light-emitting segment and the non-light-emitting segment are switched every rotation of the rotating fluorescent plate 13, the light-emitting segment in one turn and the light-emitting segment in the next turn do not overlap each other, and the non-light-emitting segment in a certain turn The non-light-emitting segments in the next round do not overlap each other.

  If the least common multiple of 25 ms (two rotations of the rotation cycle of the rotating fluorescent plate 13) between the rotation cycle of the rotating fluorescent plate 13 and 12.5 ms of the light source 11 and the light emission cycle of the light source 11 (switching cycle of the 3D glasses) 8.33 ms is 1 unit time, 1 It returns to the initial state in unit time, and the same is repeated thereafter. While the rotating fluorescent plate 13 rotates twice, the light emission period of each segment is equal to each other once. Therefore, the time average of the irradiation light quantity of each segment (segment A thru | or segment C) is mutually equal. In other words, in all the segments (segment A to segment C), the integrated light amounts of the excitation light 70 irradiated per unit time are equal to each other. Thereby, the irradiation site of the excitation light 70 is dispersed and averaged in terms of position and time, and the temperature rise due to local concentration of light in a short time is suppressed.

  FIG. 6 is a flowchart illustrating a procedure of processing executed by the control system of the projector 1.

  When the control unit 61 starts the control program and the synchronization signal generation unit of the image signal supply unit 64 starts generating the frame synchronization signal, the processing according to the flowchart of FIG.

  First, in step S1, the light emission timing generation unit 101 takes in the frame synchronization signal supplied from the image signal supply unit 64, generates a light emission timing signal synchronized with the frame synchronization signal, and determines the rotation period with the light source driving unit 62. To the unit 102. For example, the light emission timing generation unit 101 takes in a frame synchronization signal having a period of 1/120 second from the image signal supply unit 64 and generates a light emission timing signal having a period of 1/120 second synchronized with the frame synchronization signal. The light source driving unit 62 and the rotation period determining unit 102 are supplied.

  Next, in step S2, the rotation cycle determination unit 102 takes in the light emission timing signal supplied from the light emission timing generation unit 101, calculates the rotation cycle of the rotating fluorescent plate 13 that is asynchronous with the pulse cycle of this light emission timing signal, This rotation period value is supplied to the motor drive unit 63. For example, when the pulse period of the light emission timing signal is 1/120 second, the rotation period determination unit 102 applies a non-integer 1.5, 1.5 / 1.5 times 1/120 second. 120 seconds is obtained as the rotation period value and supplied to the motor drive unit 63. The non-integer value (pointing to 1.5 in this example) may be determined in advance or may be set by an operator as appropriate.

  Next, in step S3, the motor drive unit 63 takes in the rotation cycle value supplied from the rotation cycle determination unit 102, generates a rotation instruction signal specifying the rotation cycle value, supplies the rotation instruction signal to the motor 14, and drives it. For example, the motor drive unit 63 takes in the rotation cycle value 1.5 / 120 supplied from the rotation cycle determination unit 102 and uses the rotation instruction signal that specifies the rotation cycle value, that is, the rotation axis Ax of the motor 14. 120 / 1.5 = rotation instruction signal instructing to rotate at 80 rotations / second is generated and supplied to the motor 14.

  Next, the motor drive unit 63 takes in the position information of the rotation axis Ax supplied from the motor 14 and supplies the position information to the rotation cycle determination unit 102.

  Next, the rotation cycle determination unit 102 takes in the position information of the rotation axis Ax supplied from the motor drive unit 63 and determines whether the motor 14 is rotating based on this position information. When it is determined that the motor 14 is not rotating, the rotation cycle determination unit 102 sets an abnormality flag indicating an abnormal state. Then, when the abnormality flag is set, the control unit 61 generates, for example, an alarm signal and outputs it to the outside.

  In step S4, the light source driving unit 62 takes in the light emission timing signal supplied from the light emission timing generation unit 101, and causes the light source 11, the light source 20, and the light source 24 to emit light based on the light emission timing signal. For example, when the pulse period of the light emission timing signal is 1/120 seconds (the positive active period is 0.5 / 120 seconds assuming that the duty is 50%), the light source driving unit 62 performs the positive period of the light emission timing signal. In the period of 0.5 / 120 seconds, the light source 11, the light source 20, and the light source 24 are caused to emit light.

  Next, in step S <b> 5, the control unit 61 supplies an image output request signal to the image signal supply unit 64.

  Next, the image signal supply unit 64 takes in the image output request signal supplied from the control unit 61, and synchronizes the image signal supplied from the outside with the frame synchronization signal in response to the image output request signal. The liquid crystal display element 30R, the green liquid crystal display element 30G, and the blue liquid crystal display element 30B are respectively supplied.

  In the projector 1 according to the present embodiment described above, the emission period (for example, 1/120 seconds) of the excitation light emitted from the light source 11 and the rotation period (for example, 1.5 / 120 seconds) of the rotating fluorescent plate 13 are the same. Since they are different from each other and asynchronous, the region where the excitation light is irradiated on the phosphor 13b of the rotating fluorescent plate 13 moves around with time. The region irradiated with the excitation light 70 of the phosphor 13b is different for each turn, and there is a position where the excitation light is not irradiated continuously in one turn and the next turn. Therefore, the temperature rise of the phosphor 13b can be reduced as compared with the case where the region irradiated with the excitation light of the phosphor layer is always the same for each turn. Therefore, the projector 1 is provided in which the phosphor 13b is not deteriorated and the wavelength conversion efficiency of the phosphor 13b is hardly reduced.

  Further, in the projector 1 of the present embodiment, when the phosphor 13b is divided into a plurality of segments (segment A, segment B, and segment C) along the rotation direction of the rotating fluorescent plate 13, each segment is irradiated per unit time. The integrated light amounts of the excited light 70 are equal to each other. Therefore, it is possible to suppress the degree of deterioration of the phosphor 13b and the variation in wavelength conversion efficiency of the phosphor 13b from segment to segment. Therefore, it is possible to provide a projector that has a long service life and is unlikely to change in brightness for each turn.

  Here, a case where the rotation of the rotating fluorescent plate is synchronized with the intermittent light emission of the light source will be described as a comparative example. In order to irradiate excitation light equally to all the segments while synchronizing the rotation of the rotating fluorescent plate with the intermittent light emission of the light source, the rotation period of the rotating fluorescent plate must be equal to the light emission period of the light source. Otherwise, a specific segment is always irradiated with excitation light. In order to synchronize the rotation of the rotating fluorescent plate with the intermittent light emission of the light source and make the rotation period of the rotating fluorescent plate equal to the light emission period of the light source, the rotating fluorescent plate must be rotated at a very high speed. The higher the rotational speed of the rotating fluorescent screen, the higher the noise and motor power consumption. However, according to the projector 1 of the present embodiment, the rotational speed of the rotating fluorescent plate can be made lower than when the rotation of the rotating fluorescent plate is synchronized with the light emission of the light source.

[Second Embodiment]
FIG. 7 is a diagram in which the phosphor 13 b is divided into a plurality of segments (fan-shaped regions) along the rotation direction of the rotating fluorescent plate 13 in the projector of the second embodiment. FIG. 8 is a diagram showing the relationship between the rotation period of the rotating fluorescent plate 13 and the light emission timing of the light source 11. FIG. 9 is a diagram showing the segments (light-emitting segments) irradiated with the excitation light in time series for each round. In FIG. 9, “◯” indicates that the light source emits light, and “X” indicates that the light source does not emit light.

  As shown in FIG. 7, in the rotating fluorescent plate 13 of the present embodiment, the phosphor 13 b is virtually divided into 17 segments (segment A to segment Q) along the rotating direction of the rotating fluorescent plate 13. The light source is repeatedly turned on and off at a constant time interval, and the excitation light 70 is intermittently emitted to the phosphor 13b at a constant time interval. In this embodiment, as will be described later, the ratio of the light source 11 on period (light emission period) to the light source 11 off period (non-light emission period) is 7: 3, and the duty of the light emission period is 70%. . For this reason, as the rotating fluorescent plate 13 rotates, after the continuous seven segments are caused to emit light, the next consecutive three segments are not emitted. However, the central angles of the 17 segments are equal to each other. One segment in the second embodiment is a fan-shaped area obtained by dividing the fan-shaped area corresponding to the locus drawn by the condensed spot 70 while the light source 11 is turned on once into seven equal parts.

  As shown in FIG. 8, in the present embodiment, the 3D glasses are switched at 120 Hz, and the duty of the opening period (period during which image light is transmitted and the user visually recognizes an image) is 70%. Since the light emission period of the phosphor 13b (light emission period of the light source 11) is 120 Hz and the duty is 70% in accordance with the 3D glasses, the rotational speed of the rotating fluorescent plate 13 is, for example, 120 Hz × 1 / (1 + 0.7) = 70.6 Hz. (Rotation period 14.17 ms).

  As shown in FIG. 9, when viewed from the rotation of the rotating fluorescent plate 13, in the first round (period T <b> 1), the segments A to G that are continuous with each other emit light, and the segments H to S that are next to each other continue to emit light. Segment J does not emit light. Furthermore, the next consecutive segment K or segment Q emits light. In the second round after that (period T2), the next consecutive segment A or segment C does not emit light, the next consecutive segment D or segment J emits light, and the next consecutive ones. The continuous segment K or segment M does not emit light, and the next consecutive segment N or segment Q emits light. Hereinafter, as shown in FIG. 9, the non-light-emitting segment is shifted every round, returning to the original state by 10 rotations (after the period T10 has elapsed), and 10 cycles including the periods T1 to T10 are repeated.

  In this configuration, the non-light-emitting segment in one round and the non-light-emitting segment in the next round do not overlap each other.

  The least common multiple of 141.7 ms (10 rotations of the rotation period of the rotating fluorescent plate 13) between the rotation period of the rotating fluorescent plate 13 of 14.17 ms and the light emission period of the light source 11 (switching period of the 3D glasses) of 8.33 ms is assumed to be 1 unit time. It returns to the initial state in one unit time, and thereafter the same is repeated. While the rotating fluorescent plate 13 is rotated 10 times, the light emission period of each segment is equal to each other by 7 times. Therefore, the time average of the irradiation light quantity of the excitation light 70 in each segment (segment A thru | or segment Q) is mutually equal. In other words, in all the segments (segment A to segment Q), the integrated light amounts of the excitation light 70 irradiated per unit time are equal to each other. Thereby, the irradiation site of the excitation light 70 is dispersed and averaged in terms of position and time, and the temperature rise due to local concentration of light in a short time is suppressed.

  In the projector according to the present embodiment, since the duty of the light emission period exceeds 50%, it is impossible that the light emitting segment in one round and the light emitting segment in the next round do not overlap each other. Therefore, any one of the 17 segments becomes a light emitting segment in two consecutive rounds, but this is unavoidable. However, by adjusting the relationship between the number of rotations of the rotating fluorescent plate 13 and the emission frequency of the light source 11 (the emission frequency of the excitation light 70), the excitation light 70 is irradiated onto the phosphor 13b as in the first embodiment. Position can be moved around with time. Therefore, an excessive rise in the temperature of the phosphor 13b is suppressed, and a projector is provided in which the phosphor 13b is not deteriorated and the wavelength conversion efficiency of the phosphor 13b is not lowered.

[Third Embodiment]
FIG. 10 is a schematic diagram of the projector 2 according to the third embodiment.
In the present embodiment, components that are the same as those of the projector 1 of the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The projector 2 includes a red light source device 80R, a green light source device 80G, a blue light source device 80B, a color synthesis optical system 90, a micromirror light modulation element 100, and a projection optical system 50. Yes.

  The green light source device 80G includes a light source 11, a condenser lens 12a, a collimator lens 12b, a rotating fluorescent plate 13, a motor 14, a pickup optical system 15, and a dichroic mirror 16.

  The configurations of the light source 11, the condensing lens 12a, the collimating lens 12b, the rotating fluorescent plate 13, the motor 14, the pickup optical system 15, and the dichroic mirror 16 are the same as those described in the first embodiment.

  The excitation light emitted from the light source 11 is collimated by the collimating lens 36, and the light flux is once narrowed by the condenser lens 12a and the collimating lens 12b. Thereafter, the optical path is bent 90 degrees by the dichroic mirror 16, and the light is condensed on the phosphor 13 b of the rotating fluorescent plate 13 by the pickup optical system 15. The green light emitted from the phosphor 13 b is made substantially parallel by the pickup optical system 15, and after the residual excitation light is removed by the dichroic mirror 16, the green light enters the color synthesis optical system 90.

  The red light source device 80 </ b> R includes a light source 20 and a collimating lens 81. The configuration of the light source 20 is the same as that described in the first embodiment. The red light emitted from the light source 20 is substantially collimated by the collimating lens 81 and enters the color synthesis optical system 90.

  The blue light source device 80 </ b> B includes a light source 24 and a collimating lens 82. The configuration of the light source 24 is the same as that described in the first embodiment. The blue light emitted from the light source 24 is substantially collimated by the collimating lens 82 and enters the color synthesis optical system 90.

  The color synthesis optical system 90 includes a cross dichroic prism 91, a condenser lens 92, a rod integrator 93, a condenser lens 94, and a reflection mirror 95.

  The cross dichroic prism 91 is an optical member formed by bonding four right-angle prisms into a cube. A dielectric multilayer film is formed on the X-shaped interface where the right-angle prisms are bonded together. The dielectric multilayer film formed on one X-shaped interface reflects red light, and the dielectric multilayer film formed on the other interface reflects blue light. The cross dichroic prism 91 aligns the traveling directions of red light and blue light whose traveling directions are changed by the dielectric multilayer films and the transmitted green light.

  The red light source device 80R, the green light source device 80G, and the blue light source device 80B are alternately driven in a time division manner. The red light, the green light, and the blue light sequentially emitted from the red light source device 80R, the green light source device 80G, and the blue light source device 80B are collected by the condenser lens 92 after their traveling directions are aligned by the cross dichroic prism 91. The brightness distribution is made uniform by the rod integrator 93. The red light, green light, and blue light emitted from the rod integrator 93 are re-condensed by the condenser lens 94, reflected by the reflection mirror 95, and sequentially incident on the micromirror type light modulation element 100.

  The micromirror light modulator 100 is a reflective light modulator manufactured by MEMS (Micro Electro Mechanical Systems) technology. As the micromirror type light modulation element 100, for example, DMD (Digital Micromirror Device) (trademark of TI) is used. The micromirror-type light modulation element 100 modulates red light, green light, and blue light sequentially incident from the reflection mirror 95 based on an image signal supplied from the outside, and generates red image light, green image light, and blue light. Image light is generated sequentially. The red image light, the green image light, and the blue image light generated by the micromirror light modulator 100 are sequentially enlarged and projected on the screen SCR by the projection optical system 50, and are mixed by the user's eyes to form a color image. Be recognized.

  In the case of this embodiment, the projector 2 is a projector that displays a 2D image. One frame period is divided into three subframe periods, and red image light, green image light, and blue image light are sequentially generated for each subframe period. The red light source device 80R, the green light source device 80G, and the blue light source device 80B have zero output light (non-light emission) in order to suppress power consumption when image light of other colors is generated. . Therefore, in the red light source device 80R, the green light source device 80G, and the blue light source device 80B, intermittent light emission is performed in which only a specific subframe period is turned on and other subframe periods are turned off.

  FIG. 11 is a block diagram illustrating a functional configuration of a control system that controls the operation of the projector 2. In FIG. 11, only the configuration necessary for drive control of the light source 11, which is a feature of the present invention, is extracted and simplified from the configuration illustrated in FIG. 10.

  The projector 2 includes a control unit (control device) 61, a light source driving unit 62, a motor driving unit 63, and an image signal supply unit 64 as a control system.

  The control unit 61 includes a light emission timing generation unit 101 as a light emission timing generation device and a rotation cycle determination unit 102 as a rotation cycle determination device as functional configurations.

  The light emission timing generation unit 101 takes in the frame synchronization signal supplied from the image signal supply unit 64, the first light emission timing signal for controlling the emission period of the excitation light emitted from the light source 11, and the red light emitted from the light source 20. A second light emission timing signal for controlling the light emission period and a third light emission timing signal for controlling the blue light emission period emitted from the light source 24 are generated in synchronization with the frame synchronization signal. Then, the light emission timing generation unit 101 supplies the first light emission timing signal, the second light emission timing signal, and the third light emission timing signal to the light source driving unit 62. In addition, the light emission timing generation unit 101 supplies the first light emission timing signal to the rotation cycle determination unit 102.

  The frame synchronization signal is a synchronization signal that determines the frame period of the video, and is, for example, a pulse signal having a frame rate of 60 frames / second (fps). Each of the first to third light emission timing signals is, for example, a positive active pulse signal synchronized with the frame synchronization signal as described above.

  In the present embodiment, the light source 11, the light source 20, and the light source 24 emit light once every frame period. Therefore, when the frame rate of the frame synchronization signal is 60 fps, each of the first to third light emission timing signals is a positive active pulse signal having a period of 1/60 seconds synchronized with the frame frequency.

  The rotation cycle determination unit 102 takes in the first light emission timing signal supplied from the light emission timing generation unit 101, calculates the rotation cycle of the rotating fluorescent plate 13 that is asynchronous with the pulse cycle of the first light emission timing signal, and performs this rotation. A cycle value (rotation cycle value) is supplied to the motor drive unit 63. When the rotating fluorescent plate 13 is rotating, the rotation period determining unit 102 irradiates the first region of the phosphor 13b with excitation light in one rotation, and at least a part of the first region. The region is not an integral multiple of the pulse period of the first light emission timing signal (non-integer multiple) and is not a fraction of an integer (one fraction of a non-integer) so that excitation light is not irradiated in the next round. ) Obtain the rotation period value and supply the rotation period value to the motor drive unit 63.

  Further, the rotation cycle determination unit 102 takes in the position information of the rotation axis Ax of the motor 14 supplied from the motor driving unit 63 and determines whether or not the rotation axis Ax of the motor 14 is rotating based on this position information. To do.

  The light source drive unit 62 takes in the first to third light emission timing signals supplied from the light emission timing generation unit 101 of the control unit 61, and based on the timings indicated by the first to third light emission timing signals, 20 and the light source 24 emit light intermittently. That is, when the first to third light emission timing signals are positive active pulse signals, the light source driving unit 62 causes the light source 11 to emit light during the positive period of the first light emission timing signal, and the second light emission timing signal. The light source 20 emits light during the positive period, and the light source 24 emits light during the positive period of the third light emission timing signal. In the present embodiment, the level value of the excitation light emitted from the light source 11 is constant.

  The motor drive unit 63 takes in the rotation cycle value supplied from the rotation cycle determination unit 102 of the control unit 61, generates a rotation instruction signal designating this rotation cycle value, supplies the rotation instruction signal to the motor 14, and drives it. Further, the motor drive unit 63 takes in the position information of the rotation axis Ax supplied from the motor 14 and supplies the position information to the rotation cycle determination unit 102.

  The image signal supply unit 64 includes a synchronization signal generation unit (not shown), and supplies the frame synchronization signal generated by the synchronization signal generation unit to the light emission timing generation unit 101 of the control unit 61. The image signal supply unit 64 takes in the image output request signal supplied from the control unit 61, and synchronizes the image signal supplied from the outside with the frame synchronization signal in accordance with the image output request signal. The light is supplied to the light modulation element 100.

  FIG. 12 is a diagram in which the phosphor 13 b is divided into a plurality of segments (fan-shaped regions) along the rotation direction of the rotating fluorescent plate 13. FIG. 13 is a diagram showing the relationship between the rotation period of the rotating fluorescent plate 13 and the light emission timing of the light source 11. FIG. 14 is a diagram showing the segments (light-emitting segments) irradiated with the excitation light in time series for each round. In FIG. 14, “◯” indicates that the light source emits light, and “X” indicates that the light source does not emit light.

  As shown in FIG. 12, in the rotating fluorescent plate 13 of the present embodiment, the phosphor 13 b is virtually divided into four segments (segment A to segment D) along the rotating direction of the rotating fluorescent plate 13. The light source is repeatedly turned on and off at a constant time interval, and the excitation light 70 is intermittently emitted to the phosphor 13b at a constant time interval. In this embodiment, as will be described later, the ratio of the light source 11 on period (light emission period) to the light source 11 off period (non-light emission period) is 1: 2, and the duty of the light emission period is 1/3. is there. Therefore, in the present embodiment, with the rotation of the rotating fluorescent plate 13, after one segment is set as a light emitting segment, the next two consecutive segments are repeatedly set as non-light emitting segments. However, the central angles of the four segments are equal to each other. Note that one segment in the third embodiment is a fan-shaped region corresponding to a locus drawn by the condensed spot 70 while the light source 11 is turned on once.

  As shown in FIG. 13, the emission frequency of the phosphor 13b (the emission frequency of the light source) is 60 Hz, and the duty is 33%. In this case, the rotation speed of the rotating fluorescent plate is set to 120 Hz × 1 / (1 + 0.33) = 90 Hz (rotation cycle 11.1 ms), for example.

  As shown in FIG. 14, when viewed from the rotation of the rotating fluorescent plate 13, in the first round (period T <b> 1), the segment A emits light, the next consecutive segment B and segment C do not emit light, and the next The segment D is emitted. In the subsequent second round (period T2), the next consecutive segment A and segment B do not emit light, the next segment C emits light, and the next segment D does not emit light. Hereinafter, as shown in FIG. 14, the non-light-emitting segment is shifted every round, returning to the original state by three rotations (after the period T3 has elapsed), and three cycles including the periods T1 to T3 are repeated.

  In this configuration, the light emitting segment in one turn does not overlap with the light emitting segment in the next turn. While the rotating fluorescent plate 13 rotates three times, the light emission period of each segment is equal to each other once. Therefore, the time average of the irradiation light quantity of the excitation light 70 in each segment (segment A thru | or segment D) is mutually equal.

  If the least common multiple of 33.33 ms (3 rotations of the rotation period of the rotating fluorescent plate 13) between the rotation period of the rotating fluorescent plate 13 and 11.1 ms of the light source 11 and the light emission period of 16.66 ms is 1 unit time, Returning to the state, the same is repeated thereafter. While the rotating fluorescent plate 13 rotates three times, the light emission period of each segment is equal to each other once. Therefore, the time average of the irradiation light quantity of the excitation light 70 in each segment (segment A thru | or segment D) is mutually equal. In other words, in all the segments (segment A to segment D), the integrated light amounts of the excitation light 70 irradiated per unit time are equal to each other. Thereby, the irradiation site of the excitation light 70 is dispersed and averaged in terms of position and time, and the temperature rise due to local concentration of light in a short time is suppressed.

  In the projector 2 of the present embodiment, since the duty of the light emission period is less than 50%, the non-light-emitting segment in one round and the non-light-emitting segment in the next round cannot occur. For this reason, any one of the four segments becomes a light-emitting segment in two consecutive rounds, but this is unavoidable. However, by adjusting the relationship between the number of rotations of the rotating fluorescent plate 13 and the emission frequency of the light source 11 (the emission frequency of the excitation light 70), the position where the excitation light is irradiated onto the phosphor 13b as in the first embodiment. Can be moved around with time. Therefore, an excessive rise in the temperature of the phosphor 13b is suppressed, and a projector is provided in which the phosphor 13b is not deteriorated and the wavelength conversion efficiency of the phosphor 13b is not lowered.

[Fourth Embodiment]
In the first embodiment, an example in which the light source device according to the present invention is applied to a projector that displays a 3D image has been shown. However, in the fourth embodiment, the light source device according to the present invention is applied to a projector that displays a 2D image. An example is shown. However, since the configuration of the projector that displays the 2D image is the same as the configuration of the projector 1 that displays the 3D image shown in the first embodiment, the description regarding the configuration of the projector is omitted.

  In the projector according to the present embodiment, the hue of the generated image can be adjusted by adjusting the emission of green light from the phosphor 13b. Since the functional configuration of the control system that controls the operation of the projector according to the present embodiment is similar to the functional configuration of the control system that controls the operation of the projector 1, the control system will be described with reference to FIG. Further, in the projector of the fourth embodiment, as in the first embodiment, the phosphor 13b is divided into three segments (fan-shaped regions) along the rotation direction of the rotating fluorescent plate 13, so that FIG. The present embodiment will be described. In addition, the description which overlaps with 1st Embodiment is abbreviate | omitted.

  FIG. 15 is a diagram showing the relationship between the rotation period of the rotating fluorescent plate 13 and the light emission timing of the light source 11. FIG. 16 is a diagram showing the segments (light-emitting segments) irradiated with the excitation light in time series for each round. In FIG. 16, “◯” indicates that the light source emits light, and “X” indicates that the light source does not emit light.

  First, a method for controlling the light source 11 and the motor 14 will be described with reference to FIG. In the present embodiment, the light source 11 is caused to emit light intermittently in order to adjust the emission of green light from the phosphor 13b to ½ of the maximum output.

  The light emission timing generation unit 101 takes in a frame synchronization signal supplied from the image signal supply unit 64 and an adjustment coefficient for adjusting the emission of green light. The light emission timing generation unit 101 generates a light emission timing signal for controlling the emission period of the excitation light emitted from the light source 11 based on the frame synchronization signal and the adjustment coefficient, and the light emission timing signal is transmitted to the light source driving unit 62. This is supplied to the rotation cycle determination unit 102. The light emission timing signal is, for example, a positive active pulse signal. Based on this light emission timing signal, the light source 11 intermittently emits excitation light as shown in FIG.

  Let TE be the minimum unit time of light emission of the light source 11 and the minimum unit time of non-light emission of the light source 11. The minimum unit time TE of light emission is 1/12 of the frame period.

  The rotation cycle determination unit 102 takes in the light emission timing signal supplied from the light emission timing generation unit 101 and calculates the rotation cycle of the rotating fluorescent plate 13. When the rotating fluorescent plate 13 is rotating, the rotation period determining unit 102 irradiates the first region of the phosphor 13b with excitation light in one rotation, and at least a part of the first region. The rotation period value is determined so that the region is not irradiated with excitation light in other rounds. Specifically, the rotation period of the rotating fluorescent screen 13 is set to 3 times TE.

  As shown in FIG. 3, in the rotating fluorescent plate 13 of the present embodiment, the phosphor 13 b is virtually divided into three segments (segment A to segment C) along the rotation direction of the rotating fluorescent plate 13. However, the central angles of the three segments are equal to each other. Note that one segment in the fourth embodiment is a fan-shaped region corresponding to the locus drawn by the condensed spot 70 during the minimum unit time TE when the light source 11 is turned on.

  When the light emission timing signal and the rotation period of the rotating fluorescent plate 13 are set as described above, the light emission timings of the segments A to C are as shown in FIG. When viewed from the rotation of the rotating fluorescent plate 13, in the first round (period T1) and the second round following the first round (period T2), the segment A is a light-emitting segment, and the next segment B is non-light-emitting. Segment C, and the next segment C is a light emitting segment. In the third round (period T3) following the second round and the fourth round (period T4) following the third round, the segment A is a non-light emitting segment, and the next segment B is a light emitting segment. Yes, the next segment C is a non-luminous segment. In the fifth round (period T5) following the fourth round, the segment A is again a light emitting segment, the next segment B is a non-light emitting segment, and the next segment C is a light emitting segment. As described above, the fifth cycle after the fourth cycle (period T4) returns to the first cycle (period T1) again, and four cycles including the periods T1 to T4 are repeated.

  At the above light emission timing, the segment A and the segment C are irradiated with excitation light following the first and second rounds. However, the segment A and the segment C are not irradiated with the excitation light after the third and fourth rounds (period T4) following the second round. Therefore, the temperature rise of the phosphor 13b can be reduced as compared with the case where the region irradiated with the excitation light of the phosphor layer is always the same for each turn.

  As shown in FIG. 15, the average light intensities of the green light emitted from the green light source device 10G in each frame period are equal to each other, and the green light is emitted from the green light source device 10G for the entire period in each frame cycle. Compared with the case where it does, the average light intensity of green light can be weakened to 1/2. In this way, it is possible to adjust the hue of the generated image.

  Furthermore, if the frame period is 1 unit time, the period during which each segment emits light during 1 unit time is equal to 2 times. Therefore, the time averages of the excitation light irradiation light amounts of the segments (segment A to segment C) are equal to each other. In other words, in all the segments (segment A to segment C), the integrated light amounts of the excitation light 70 irradiated per unit time are equal to each other. Thereby, the irradiation site of the excitation light 70 is dispersed and averaged in terms of position and time, and the temperature rise due to local concentration of light in a short time is suppressed.

[Deformation]
In the first to third embodiments, the phosphor layer 13b is provided on the disc 13a. However, a substrate in which the phosphor is dispersed inside the disc 13a may be used.

  In the first to third embodiments, as an example of a projector that causes the light source 11 to emit light intermittently, a 3D display projector that provides a non-light emitting period between an image for the right eye and an image for the left eye, and a field sequential method The 2D display projector that sequentially generates red image light, green image light, and blue image light has been described. However, the configuration of the projector is not limited to this. The present invention can be widely applied to a configuration in which the light source is intermittently emitted to irradiate the phosphor 13b on the rotating substrate intermittently with excitation light.

10G ... light source device, 11 ... light source, 13a ... disc (substrate), 13b ... phosphor (phosphor layer), 30G ... green liquid crystal display element (light modulation element), 50 ... projection optical system, 61 ... control unit (Control device), 70 ... excitation light, 80G ... light source device, 100 ... micromirror type light modulation element (light modulation element), 101 ... light emission timing generation unit (light emission timing generation device), 102 ... rotation period determination unit (rotation) Period determining device), A to Q: Segment, Ax: Rotating shaft

Claims (11)

A substrate including a phosphor layer and rotatable about a predetermined rotation axis;
A light source that intermittently emits excitation light for exciting the phosphor layer;
When the substrate is rotated, the first region of the phosphor layer is irradiated with the excitation light in one turn, and at least a part of the first region is exposed to another region. in the circulation, as the excitation light is not irradiated, and a rotation period determining device for controlling the rotation of the substrate,
When the phosphor layer is divided into a plurality of segments along the rotation direction of the substrate, the integrated light amount of the excitation light irradiated to the first segment among the plurality of segments per unit time is the unit time. The light source device that is equal to the integrated light amount of the excitation light irradiated to a second segment different from the first segment among the plurality of segments .   The rotation period determining device includes a region in the phosphor layer that is irradiated with the excitation light during the rotation of the phosphor layer and the other rotation of the phosphor layer when the substrate is rotating. The light source device according to claim 1, wherein the rotation of the substrate is controlled so as not to overlap with a region irradiated with excitation light.   When the substrate is rotating, the rotation period determining device includes a region of the phosphor layer that is not irradiated with the excitation light in the one round, and the excitation in the other round of the phosphor layer. The light source device according to claim 1, wherein the rotation of the substrate is controlled so as not to overlap with a region not irradiated with light. It said other lap, the light source device according to any one of claims 1 to 3 wherein the next lap of one lap. The light source device according to claim 4 , wherein in all the segments, the integrated light amounts of the excitation light irradiated per unit time are equal to each other. As a light emission timing signal for controlling the light emission timing of the light source, further comprising a light emission timing generation device for generating a light emission timing signal having a period synchronized with a frame period,
The rotation period determining unit, as the rotation period of the substrate, a light source device according to any one of claims 1 to 5 for determining the non-integer multiple rotation period of the period of the emission timing signal. The rotation period determining unit, the duty of the emission period of the light source as δ (0 <δ <1) , according to claim 6 to determine the (1 + δ) times the period of the period of the light emission timing signal as the rotation period of the substrate The light source device according to 1. The light source device according to claim 7 , wherein the duty δ is 0.5 or less. A substrate including a phosphor layer and rotatable about a predetermined rotation axis;
A light source that intermittently emits excitation light for exciting the phosphor layer;
When the rotation of the substrate is asynchronous with the emission of the excitation light and the phosphor layer is divided into a plurality of segments along the rotation direction of the substrate, the plurality of segments per unit time Among the plurality of segments, the integrated light amount of the excitation light irradiated to the first segment is the integrated light amount of the excitation light irradiated to the second segment different from the first segment per unit time. A rotation period determining device for controlling the rotation of the substrate to be equal;
A light source device comprising: The light source device according to claim 9 , wherein in all the segments, the integrated light amounts of the excitation light irradiated per unit time are equal to each other. A light source device according to any one of claims 1 to 1 0,
A light modulation element that modulates light emitted from the light source device with an image signal;
A projection optical system for projecting a pre-Symbol light modulated by the light modulation device,
Projector equipped with.

Images