JP2005257872A - Lighting device and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device capable of supplying high-luminance illuminating light excellent in terms of light utilization efficiency, and a projector equipped with the lighting device. <P>SOLUTION: The lighting device has at least two solid-state light emitting elements for supplying light, that is, a 1st LED 101a being a 1st solid-state light emitting element and a 2nd LED 101b being a 2nd solid-state light emitting element, a polarizing beam splitter 104 being a polarized light composing part which transmits or reflects p-polarized light in a 1st vibrating direction and reflects or transmits s-polarized light in a 2nd vibrating direction nearly orthogonal to the 1st vibrating direction, thereby guiding the polarized light in the 1st vibrating direction and the polarized light in the 2nd vibrating direction to an illuminating direction IL, and a liquid crystal panel 106 being a phase modulation element which changes the polarized light from the beam splitter 104 being the polarized light composing part to the polarized light in the 1st vibrating direction or the polarized light in the 2nd vibrating direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an illuminating device, in particular, an illuminating device for illuminating a spatial light modulator, and a projector that projects an image using the spatial light modulator and the illuminator.

  A light-emitting diode (hereinafter referred to as “LED”) generally has an advantage that it has a long life and high conversion efficiency to light as compared with an ultra-high pressure mercury lamp or the like. For this reason, there are many cases where LEDs are used as the light source of the illumination device. Here, a single LED has a smaller amount of light emission than an ultra-high pressure mercury lamp or the like. A light source such as a projector requires a relatively large amount of light. For this reason, when using LED for the light source of a projector, the proposal which makes an array in order to enlarge light quantity is made | formed (for example, refer patent document 1).

JP 2001-305657 A

  When arranging a plurality of LEDs in an array, the amount of light can be increased in proportion to the number of LEDs. Here, in a projector, in an optical system including a light source and a spatial light modulation device, a spatial spread in which a light beam that can be effectively handled exists can be expressed as a product of an area and a solid angle (Etendue, Geometric Extent). . The product of the area and the solid angle is stored in the optical system. Therefore, when the spatial extent of the light source increases, the spatial extent in which the light beam incident on the spatial light modulation device exists increases. However, since the angle that can be captured by the spatial light modulator is limited, it is difficult to effectively use the light flux from the light source. When a plurality of LEDs are arrayed to increase the amount of light, the area (spatial expansion) of the light source also increases. Therefore, in the projector, even if an attempt is made to simply increase the amount of light by arraying LEDs, since the etendue is preserved, it becomes difficult to effectively use all light beams from the light source. As a result, the amount of light cannot be increased, which is a problem.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an illumination device that can supply illumination light with high luminance and high light use efficiency, and a projector including the illumination device.

  In order to solve the above-described problem, according to the first invention, at least two solid-state light-emitting elements of a first solid-state light-emitting element and a second solid-state light-emitting element that supply light, and polarized light in a first vibration direction The polarized light in the first vibration direction and the polarized light in the second vibration direction are transmitted or reflected by reflecting or transmitting the polarized light in the second vibration direction substantially orthogonal to the first vibration direction. And a phase modulation element that converts polarized light from the polarized light combining unit into polarized light in the first vibration direction or polarized light in the second vibration direction. A lighting device can be provided. For example, the first solid-state light emitting element emits randomly polarized light including p-polarized light that is polarized light in the first vibration direction. In addition, the second solid-state light emitting element emits randomly polarized light including s-polarized light that is polarized light in the second vibration direction, for example. The polarized light combining unit can use, for example, a polarized beam splitter including a polarizing film that transmits p-polarized light and reflects s-polarized light. At this time, the polarized light combining unit is configured to transmit the p-polarized light from the first solid-state light-emitting element, reflect the s-polarized light from the second solid-state light-emitting element, and guide it in the same illumination direction. Further, the first solid state light emitting element and the second solid state light emitting element are arranged so as to be in an optically equivalent position when viewed from the illuminated direction. Thereby, the light from at least two solid light emitting elements can be guided to the optical path in the same illumination direction without increasing the area of the light emitting region of the solid light emitting elements. The phase modulation element has a function of aligning the polarized light from the polarized light combining unit in the first vibration direction or the second vibration direction. Thereby, it is possible to supply illumination light with high luminance and high light utilization efficiency with the polarization direction aligned in the illumination direction.

  Further, preferably, when two solid light emitting elements are used, it is desirable to turn on the first solid light emitting element and the second solid light emitting element alternately. A solid light emitting element, for example, an LED, can reduce temperature rise by intermittent driving. As the temperature rise is reduced, the injection current can be increased. The amount of light flux increases as the injection current is increased. For this reason, by intermittently driving the two LEDs, the amount of light flux of each LED can be increased, and high-luminance illumination light can be obtained. At this time, the phase modulation element is driven in synchronization with the timing at which the two solid state light emitting elements are alternately driven intermittently. Thereby, illumination light with higher brightness can be obtained. Note that the number of solid state light emitting elements is not limited to two, and may be three or more.

  Moreover, according to the preferable aspect of the first aspect of the present invention, the first vibration direction or the second vibration direction of the light from the solid light emitting element is provided between at least two solid light emitting elements and the polarized light combining unit. Reflective polarizing plate that transmits polarized light in the other direction and reflects polarized light in other vibration directions, and reflection that reflects light reflected by the reflective polarizing plate and travels toward the solid state light emitting device toward the polarized light combining unit It is desirable to have a part. Consider a case where a reflective polarizing plate transmits polarized light having a specific vibration direction, for example, p-polarized light, and reflects polarized light having a vibration direction different from p-polarized light, for example, s-polarized light. The p-polarized light that has passed through the reflective polarizing plate exits the polarized light combining unit. On the other hand, the polarized light reflected by the reflective polarizing plate is returned to the direction of the solid light emitting element. The solid light emitting element is formed with a reflecting portion that reflects incident light. The polarized light reflected by the reflecting portion is incident on the reflective polarizing plate again. Such repetitive reflection between the reflective polarizing plate and the reflecting portion causes the phase to change, and light that has changed to p-polarized light exits the reflective polarizing plate. Unless light absorption and loss are taken into account, the light that is repeatedly reflected is finally emitted as p-polarized light. Thereby, the light from a solid light emitting element can be used with high efficiency.

  More preferably, it is desirable to provide a wave plate, for example, a λ / 4 wave plate, between the solid light emitting element and the reflective polarizing plate. When light passes through the λ / 4 wavelength plate twice, the vibration direction is rotated by 90 °. For example, s-polarized light passes through a λ / 4 wavelength plate twice and is converted to p-polarized light. Thereby, p-polarized light can be more efficiently emitted from the reflective polarizing plate.

  According to a preferred aspect of the present invention, the polarized light emitted from the polarized light combining unit in the direction different from the illumination direction is reflected to the direction of the polarized light combining unit, and reflected by the mirror to travel toward the solid state light emitting device. It is desirable to have a reflecting portion that reflects the light to be reflected in the direction of the polarized light combining portion. Thereby, the phase of the light that is repeatedly reflected between the mirror and the solid-state light emitting element changes. For example, the light in the p direction is emitted in the illumination direction by the polarized light combining unit. Thereby, illumination light with high luminance can be obtained by using light from the solid state light emitting element with high efficiency.

  According to a preferred aspect of the present invention, the phase modulation element is desirably a liquid crystal type modulation element. A liquid crystal type modulation element, for example, a liquid crystal panel, modulates incident light according to an input signal and emits it. For this reason, for example, s-polarized light can be easily converted into p-polarized light. Thus, the illumination device can supply illumination light having a uniform polarization component.

  According to the second aspect of the present invention, the above-described illumination device, the spatial light modulation device that modulates the illumination light from the illumination device according to the image signal, and the projection lens that projects the modulated light are provided. Can be provided. The projector includes a lighting device with high brightness and high light use efficiency. For this reason, a bright and high-quality projected image can be obtained.

  Hereinafter, a lighting device and a projector according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by these Examples.

  FIG. 1 shows a schematic configuration of a lighting apparatus 100 according to Embodiment 1 of the present invention. The lighting device 100 includes a first LED 101a that is a first solid-state light emitting element and a second LED 101b that is a second solid-state light emitting element. Both the first LED 101a and the second LED 101b emit light in the same wavelength region, for example, green light (hereinafter referred to as “G light”). First, G light from the first LED 101a will be described. The G light from the first LED 101a enters the collimator lens CLa. The collimator lens CLa converts incident light into substantially parallel light and emits it. The substantially parallel light is incident on the polarization beam splitter 104 which is a polarized light combining unit. On the surface of the polarizing beam splitter 104 on the first LED 101a side, a λ / 4 wavelength plate 102a that is a wavelength plate and a first reflective polarizing plate 103a are fixed with an optical transparent adhesive.

  The first reflective polarizing plate 103a transmits polarized light in the first vibration direction or the second vibration direction, for example, p-polarized light, and reflects polarized light in other vibration directions, for example, s-polarized light. As the first reflective polarizing plate 103a, a wire grid polarizer in which wires made of metal, for example, aluminum, are provided in a grid pattern on a substrate made of an optically transparent glass member can be used. The wire grid polarizer transmits polarized light whose vibration direction is substantially perpendicular to the wire and reflects polarized light whose vibration direction is substantially parallel to the wire. By providing the wire grid polarizer so that the wire is substantially perpendicular to the vibration direction of polarized light in a specific vibration direction, only polarized light in a specific vibration direction can be transmitted. In the present embodiment, the first reflective polarizing plate 103a transmits, for example, p-polarized light.

  The transmitted p-polarized light enters the polarization beam splitter 104. In the polarizing beam splitter 104, the polarizing film 105 is formed at approximately 45 ° with respect to the optical axis AX. The polarizing film 105 transmits p-polarized light and reflects s-polarized light. For this reason, the p-polarized light transmitted through the first reflective polarizing plate 103a is transmitted through the polarization beam splitter 104 and emitted in the illumination direction IL.

  In addition, a component different from the p-polarized light reflected by the first reflective polarizing plate 103a, for example, s-polarized light, passes through the λ / 4 wavelength plate 102a, which is a wavelength plate, and returns in the direction of the first LED 101a. The first LED 101a includes a reflection unit 101r that reflects light that is reflected by the first reflective polarizing plate 103a and travels in the direction of the first LED 101a in the direction of the polarization beam splitter 104 that is a polarized light combining unit. The reflective portion 101r has a function of a reflective metal electrode. The s-polarized light reflected by the reflecting portion 101r passes through the λ / 4 wavelength plate 102a again. When polarized light passes through the λ / 4 wavelength plate 102a twice, the vibration direction is rotated by 90 °. As a result, the s-polarized light passes through the λ / 4 wavelength plate 102a twice and is converted to p-polarized light. The converted p-polarized light passes through the first reflective polarizing plate 103 a and is emitted from the polarizing beam splitter 104. By such repeated reflection between the first reflective polarizing plate 103a and the reflective portion 101r, the phase is changed and light that becomes p-polarized light is emitted from the reflective polarizing plate 103a. Unless light absorption and loss are taken into account, the light that is repeatedly reflected is finally emitted as p-polarized light. Thereby, the light from the first LED 101a can be used with high efficiency.

  Next, the second LED 101b that is the second solid state light emitting device will be described. As described above, the second LED 101b emits G light in the same wavelength region as the first LED 101a. The G light from the second LED 101b enters the collimator lens CLb. The collimator lens CLb converts incident light into substantially parallel light and emits it. The substantially parallel light is incident on the polarization beam splitter 104 which is a polarized light combining unit. On the surface of the polarizing beam splitter 104 on the second LED 101b side, a λ / 4 wavelength plate 102b that is a wavelength plate and a second reflective polarizing plate 103b are fixed with an optically transparent adhesive.

  For example, the second reflective polarizing plate 103b transmits s-polarized light and reflects p-polarized light. The s-polarized light transmitted through the second reflective polarizing plate 103b is incident on the polarization beam splitter 104. The polarizing film 105 transmits p-polarized light and reflects s-polarized light. Therefore, the s-polarized light transmitted through the second reflective polarizing plate 103b is reflected by the polarizing film 105 of the polarizing beam splitter 104 and is emitted in the illumination direction IL.

  The p-polarized light reflected by the second reflective polarizing plate 103b is transmitted through the λ / 4 wavelength plate 102b, which is a wavelength plate, and returns to the direction of the second LED 101b. The second LED 101b includes a reflection unit 101r that reflects the light reflected by the second reflective polarizing plate 103b and traveling in the direction of the second LED 101b in the direction of the polarization beam splitter 104 that is a polarized light combining unit. The p-polarized light reflected by the reflecting portion 101r is transmitted again through the λ / 4 wavelength plate 102b. When it passes through the λ / 4 wavelength plate 102b twice, the vibration direction is rotated by 90 °. As a result, the p-polarized light passes through the λ / 4 wavelength plate 102b twice and is converted into s-polarized light. The converted s-polarized light passes through the second reflective polarizing plate 103b. Then, the transmitted s-polarized light is reflected by the polarizing film 105 of the polarizing beam splitter 104 and emitted. By such repeated reflection between the second reflective polarizing plate 103b and the reflecting portion 101r, the phase is changed and light that becomes s-polarized light is emitted from the second reflective polarizing plate 103b. If light absorption and loss are not taken into consideration, the light that is repeatedly reflected is finally emitted as s-polarized light. Thereby, the light from the second LED 101b can be used with high efficiency. Further, when the illumination device 100 is viewed from the illumination direction IL, the first LED 101a and the second LED 101b are disposed so as to be in an optically equivalent position. Thereby, the light from at least two solid light emitting elements 101a and 101b can be guided to the optical path in the same illumination direction IL without increasing the area of the light emitting region of the solid light emitting element.

  In place of the reflective polarizing plate, a conventional polarization conversion element using a plurality of polarization beam splitter arrays can be used. When a polarizing beam splitter array is used, the area of the light emitting region increases. For this reason, when satisfy | filling the predetermined etendue defined beforehand, a polarization beam splitter array can be used.

  Even when the λ / 4 wave plates 102a and 102b, which are wave plates, are not used, it is possible to obtain illumination light with high luminance and high light use efficiency, although the polarization conversion efficiency is somewhat reduced.

  Next, a liquid crystal type modulation element that is a phase modulation element, for example, the liquid crystal panel 106 modulates incident light according to an input signal and emits the modulated light. Note that the liquid crystal panel 106 does not require a polarizing plate or the like, and for example, a TN mode liquid crystal panel can be used. The liquid crystal panel 106 can easily convert, for example, s-polarized light into p-polarized light. Thus, the illumination device can supply illumination light having a uniform polarization component. Thereby, it is possible to supply the illumination light with high brightness and high light utilization efficiency with the polarization direction aligned in the illumination direction IL.

  In addition, it is desirable to turn on and off the first LED 101a and the second LED 101b alternately. A solid light emitting element, for example, an LED, can reduce temperature rise by intermittent driving. As the temperature rise is reduced, the injection current can be increased. The amount of light flux increases as the injection current is increased. For this reason, by intermittently driving the two LEDs 101a and 101b, the amount of luminous flux of each LED can be increased, and illumination light with high brightness can be obtained. FIG. 2-1 shows the relationship between the lighting time (horizontal axis: time t) and the injected current (vertical axis: current I) when driving one LED of the prior art. FIG. 2-2 shows the relationship between the lighting time of the first LED 101a and the injected current. Furthermore, FIG. 2-3 shows the relationship between the lighting time of the second LED 101b and the injected current. As shown in FIGS. 2-2 and 2-3, when the two LEDs 101a and 101b are alternately intermittently lit, the lighting time of each LED can be halved compared to the prior art. Since the lighting time is shortened, the injection current can be doubled compared to the prior art. As a result, high-intensity illumination light can be obtained.

  Further, the current injected into the LEDs 101a and 101b may be set to the current value I as in the conventional technique. At this time, since the amount of heat generated is reduced by intermittent driving, the light emission efficiency of the LEDs 101a and 101b can be increased. Therefore, also in this case, illumination light with high luminance can be obtained.

  In addition, the liquid crystal panel 106, which is a phase modulation element, is driven in synchronization with the timing at which the two LEDs 101a and 101b are alternately intermittently driven. For example, when the first LED 101a is lit, the liquid crystal panel 106 transmits p-polarized light as it is in the off state. On the other hand, when the first LED 101a is turned off and the second LED 101b is turned on, the liquid crystal panel 106 is turned on to rotate the p-polarized light by 90 ° to be converted into s-polarized light and transmit it. Thereby, for example, high-luminance illumination light aligned with p-polarized light can be obtained. The liquid crystal panel 106 may have a configuration in which the phase is rotated in the off state and transmitted as it is in the on state.

  Further, a ferroelectric such as PLZT can be used as the phase modulation element. PLZT is a material having an electro-optic effect (EO effect). When an electric field is applied to these crystals and ceramics, the refractive index changes. The phase can be rotated by changing the refractive index.

  Further, the number of LEDs that are solid-state light emitting elements is not limited to two, and can be configured by three or more. For example, FIG. 3 is a configuration example of an illumination device 300 that uses three LEDs 101a, 101b, and 101c. The configuration from the LEDs 101a and 101b to the liquid crystal panel 106 is the same as that in the first embodiment. Furthermore, it has 3rd LED101c, the polarizing beam splitter 114, the polarizing film 115, and the liquid crystal panel 116. FIG. The same optical system as that of the second LED 101b of the first embodiment is configured so that s-polarized light is efficiently derived from the third LED 101c. Finally, the liquid crystal panel 116 aligns the p-polarized light. Thereby, illumination light with higher brightness can be obtained. In the case of this modification, the lighting time of one LED may be T / 3.

  Furthermore, FIG. 4 shows a schematic configuration of an illumination device 400 using four LEDs as another modification. The lighting device 400 is configured to face the two sets of the lighting device 100 of the first embodiment described above. The G light from each illumination device 100 is guided to the rod lens 401 by the triangular prisms 401a and 401b. In the case of this modification, the lighting time of one LED may be T / 2. According to this modification, illumination light with higher brightness can be obtained.

  FIG. 5 shows a schematic configuration of a lighting apparatus 500 according to Embodiment 2 of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In this embodiment, a mirror 501 is used instead of the reflective polarizing plate. The mirror 501 is fixed to a surface that emits in a direction different from the illumination direction IL of the polarization beam splitter 104. The light from the first LED 101 a is incident on the polarizing film 105 of the polarizing beam splitter 104. For example, the polarizing film 105 transmits p-polarized light and reflects s-polarized light. The s-polarized light reflected by the polarizing film 105 has its optical path bent by 90 ° and enters the mirror 501. Then, the s-polarized light reflected by the mirror 501 is reflected by the polarizing film 105 in the direction of the first LED 101a. The reflected s-polarized light passes through the λ / 4 wavelength plate 102a and the collimator lens CLa and is reflected by the reflecting portion 101r. Then, the reflected s-polarized light passes through the λ / 4 wavelength plate 102a again. The s-polarized light is converted into p-polarized light by passing through the λ / 4 wavelength plate 102a twice. The converted p-polarized light passes through the polarizing film 105 and exits from the polarizing beam splitter 104.

  Next, light from the second LED 101b will be described. The light from the second LED 101b enters the polarizing film 105 of the polarizing beam splitter 104. The s-polarized light reflected by the polarizing film 105 has its optical path bent by 90 ° and exits from the polarizing beam splitter 104. On the other hand, the p-polarized light transmitted through the polarizing film 105 enters the mirror 501. Then, the p-polarized light reflected by the mirror 501 passes through the polarizing film 105. The transmitted s-polarized light passes through the λ / 4 wavelength plate 102b and the collimator lens CLb, and is reflected by the reflecting portion 101r. The reflected s-polarized light passes through the λ / 4 wavelength plate 102b again. Then, the p-polarized light is converted into s-polarized light by passing through the λ / 4 wavelength plate 102b twice. The converted s-polarized light is reflected by the polarizing film 105 and exits from the polarizing beam splitter 104.

  And like the said Example 1, 1st LED101a and 2nd LED101b are intermittently driven alternately. At the same time, the liquid crystal panel 106 is turned on and off in synchronization with the intermittent drive timing. Thereby, it is possible to obtain, for example, p-polarized illumination light in which the polarization directions with high luminance and high light utilization efficiency are aligned.

  FIG. 6 shows a schematic configuration of a projector 600 according to Embodiment 3 of the present invention. The projector 600 includes a first light source unit 601R that supplies red light (hereinafter referred to as “R light”) that is first color light, and the illumination device described in the first embodiment that supplies G light that is second color light. A second light source unit 100, and a third light source unit 601B for supplying B light as third color light. Each light source unit is a solid-state light emitting element composed of LEDs.

  The R light from the first light source unit 601R passes through the collimator lens 602R and enters the polarization conversion element 603R. The polarization conversion element 603R converts the R light into polarized light having a specific vibration direction, for example, p-polarized light. The polarization-converted R light is incident on the R light spatial light modulation device 610R which is the first color light spatial light modulation device. The spatial light modulator for R light 610R is a transmissive liquid crystal display device that modulates R light according to an image signal. The R light spatial light modulator 610R includes a liquid crystal panel 615R, a first polarizing plate 616R, and a second polarizing plate 617R.

  The first polarizing plate 616R transmits the R light converted into p-polarized light and makes it incident on the liquid crystal panel 615R. The liquid crystal panel 615R modulates p-polarized light according to an image signal and converts it into s-polarized light. The second polarizing plate 617R emits R light converted into s-polarized light by the liquid crystal panel 615R. In this manner, the R light spatial light modulation device 610R modulates the R light from the first light source unit 601R. The R light converted into s-polarized light by the spatial light modulator for R light 610R enters the cross dichroic prism 612.

  G light from the illumination device 100 as the second light source unit enters the polarization conversion element 603G. The polarization conversion element 603G converts the G light into polarized light having a specific vibration direction, for example, s-polarized light. The polarization-converted G light is incident on a G light spatial light modulation device 610G which is a second color light spatial light modulation device. The G light spatial light modulation device 610G is a transmissive liquid crystal display device that modulates G light according to an image signal. The G light spatial light modulator 610G includes a liquid crystal panel 615G, a first polarizing plate 616G, and a second polarizing plate 617G.

  The first polarizing plate 616G transmits the G light converted into the s-polarized light and makes it incident on the liquid crystal panel 615G. The liquid crystal panel 615G modulates the s-polarized light according to the image signal and converts it into p-polarized light. The second polarizing plate 617G emits G light converted into p-polarized light by the liquid crystal panel 615G. In this way, the G light spatial light modulation device 610G modulates the G light from the second light source unit 100. The G light converted into the p-polarized light by the G light spatial light modulator 610 </ b> G is incident on the cross dichroic prism 612.

  The B light from the third light source unit 601B passes through the collimator lens 602B and enters the polarization conversion element 603B. The polarization conversion element 603B converts the B light into polarized light having a specific vibration direction, for example, p-polarized light. The polarization-converted B light is incident on the B light spatial light modulation device 610B which is the third color light spatial light modulation device. The B light spatial light modulation device 610B is a transmissive liquid crystal display device that modulates B light according to an image signal. The B light spatial light modulator 610B includes a liquid crystal panel 615B, a first polarizing plate 616B, and a second polarizing plate 617B.

  The first polarizing plate 616B transmits the B light converted into the p-polarized light and makes it incident on the liquid crystal panel 615B. The liquid crystal panel 615B modulates p-polarized light according to an image signal and converts it into s-polarized light. The second polarizing plate 617B emits B light converted into s-polarized light by the liquid crystal panel 615B. In this way, the B light spatial light modulation device 610B modulates the B light from the third light source unit 601B. The B light converted into the s-polarized light by the B light spatial light modulator 610B enters the cross dichroic prism 612.

  The cross dichroic prism 612 has two dichroic films 612a and 612b. The two dichroic films 612a and 612b are arranged orthogonal to the X shape. The dichroic film 612a reflects R light that is s-polarized light and transmits G light that is p-polarized light. The dichroic film 612b reflects B light, which is s-polarized light, and transmits G light, which is p-polarized light. As described above, the cross dichroic prism 612 includes the R light modulated by the first color light spatial light modulation device 610R, the second color light spatial light modulation device 610G, and the third color light spatial light modulation device 610B. Synthesize G light and B light. The projection lens 630 projects the light combined by the cross dichroic prism 612 onto the screen 640.

  The projector 600 uses the lighting device 100 that supplies light with high light utilization efficiency and high brightness. For this reason, a bright, high-quality and good projection image can be obtained. In particular, in the above configuration, in order to project R light, G light, and B light to obtain a white projected image as a whole, the amount of G light is 60% to 80% of the total amount of light. It needs to be about. For this reason, when the amount of luminous flux emitted by the LED, which is a single solid-state light emitting element, is the same, it is necessary to arrange more LEDs of the illumination device 100 than the LEDs of the first light source unit 101R and the third light source unit 101B. In the present embodiment, the lighting device 100 intermittently drives the two LEDs 101a and 101b. For this reason, as described in the first embodiment, the luminous flux amount of the G light from the illumination device 100 which is the second light source unit is the luminous flux amount from the first light source unit 101R and the second light source unit 101B made of a single LED. Can be bigger. Moreover, the illuminating device 100 which is a 2nd light source part is the same as when the light emission area is single LED. For this reason, high brightness illumination light can be obtained without increasing etendue for G light. As a result, a good projected image can be obtained.

1 is a schematic configuration diagram of a lighting device according to Embodiment 1. FIG. The drive timing diagram of the lighting device of a prior art. FIG. 3 is a drive timing diagram of the lighting apparatus according to the first embodiment. FIG. 6 is another drive timing chart of the illumination device according to the first embodiment. FIG. 6 is a schematic configuration diagram of a modified example of the illumination device according to the first embodiment. FIG. 6 is a schematic configuration diagram of another modification of the lighting device according to the first embodiment. FIG. 6 is a schematic configuration diagram of a lighting device according to a second embodiment. FIG. 10 is a schematic configuration diagram of a projector according to a third embodiment.

Explanation of symbols

  100 Illuminator, 101a, 101b, 101c LED, CLa, CLb, CLc Collimator lens, 102a, 102b, 102c λ / 4 wavelength plate, 103a, 103b, 103c Reflective polarizing plate, 104 Polarizing beam splitter, 105 Polarizing film, 106 liquid crystal panel, AX optical axis, IL illumination direction, 116 liquid crystal panel, 300 illumination device, 400 illumination device, 401a, 401b triangular prism, 500 illumination device, 501 mirror, 600 projector, 601R, 601B light source for each color light, 603R, 603G, 603B Polarization conversion element, 610R, 610G, 610B Spatial light modulator for each color light, 612 Cross dichroic prism, 612a, 612b Dichroic film, 615R, 615G, 615B Liquid crystal panel, 6 6R, 616G, 616B, 617R, 617G, 617B polarizer, 630 a projection lens, 640 a screen

Claims (5)

At least two solid state light emitting elements, a first solid state light emitting element and a second solid state light emitting element, for supplying light;
By transmitting or reflecting polarized light in the first vibration direction and reflecting or transmitting polarized light in the second vibration direction substantially orthogonal to the first vibration direction, the polarized light in the first vibration direction A polarized light combining unit for guiding the polarized light in the second vibration direction to the illumination direction;
An illumination apparatus comprising: a phase modulation element that converts polarized light from the polarized light combining unit into polarized light in the first vibration direction or polarized light in the second vibration direction. Provided between at least two of the solid state light emitting elements and the polarized light combining unit, and transmits polarized light in the first vibration direction or the second vibration direction among the light from the solid state light emitting elements, A reflective polarizing plate that reflects polarized light in the vibration direction;
The illumination apparatus according to claim 1, further comprising: a reflection unit configured to reflect the light reflected by the reflective polarizing plate and traveling in the direction of the solid state light emitting device toward the polarized light combining unit. A mirror that reflects polarized light emitted from the polarized light combining unit in a direction different from the illumination direction in the direction of the polarized light combining unit;
The illumination device according to claim 1, further comprising: a reflection unit configured to reflect light reflected by the mirror and traveling toward the solid-state light emitting element toward the polarized light combining unit.   The lighting device according to claim 1, wherein the phase modulation element is a liquid crystal type modulation element. The lighting device according to any one of claims 1 to 4,
A spatial light modulation device that modulates illumination light from the illumination device according to an image signal;
A projector having a projection lens for projecting modulated light.

Images