JP2006220912A - Illuminator and picture display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an illuminator or the like capable of reducing the spread of luminous flux and supplying light with high efficiency. <P>SOLUTION: The illuminator has: light emitting parts 101 and 102 supplying light; a polarized light separation part 108 separating the light from the light emitting parts 101 and 102 to polarized light in a first vibrating direction and polarized light in a second vibrating direction; and reflection parts 103 and 104 reflecting the light advancing in a direction from the polarized light separation part 108 to the light emitting parts 101 and 102 to the direction of the polarized light separation part 108. The polarized light separation part 108 composes the polarized light in the first vibrating direction transmitted through the polarized light separation part 108 with the polarized light in the second vibrating direction reflected by the polarized light separation part 108 and makes the light advance to the direction of a surface to be irradiated I. Furthermore, the illuminator has a uniformization part 111 making the intensity distribution of the luminous flux nearly uniform and shaping the outside shape of the luminous flux to nearly similar shape to the surface to be irradiated I, and a polarized light changing part 112 changing the light composed by the polarized light separation part 108 to either the polarized light in the first vibrating direction or the polarized light in the second vibrating direction. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lighting device and an image display device, and more particularly to a technology of a lighting device used in combination with a spatial light modulation device.

  In recent years, it has been proposed to use a solid-state light emitting element for a projector illumination device. A light-emitting diode (hereinafter referred to as “LED”), which is a solid-state light-emitting element, is characterized by being ultra-compact, ultra-light, and long-life. Moreover, remarkable progress has been made in the development and improvement of high-power LEDs, and the use of LEDs for lighting applications is expanding. For this reason, it is expected to use an LED as a light source of a projector, particularly a small and bright projector.

  A liquid crystal type spatial light modulation device used in a projector performs modulation by converting the polarization state of incident light. When a liquid crystal spatial light modulator is used, the light from the light source can be used efficiently by converting the light from the light source into polarized light having a specific vibration direction and supplying it. For example, Patent Document 1 and Patent Document 2 propose a technique for converting light into polarized light having a specific vibration direction and supplying the light.

JP 2000-212499 A JP 2003-57445 A

  When the currently developed LED is used for a projector, it is necessary to use a plurality of LEDs in order to obtain a bright image. When a plurality of LEDs are used, the LEDs are arranged in an array according to the techniques of Patent Document 1 and Patent Document 2. When a plurality of LEDs are arranged in an array, the area in which the LEDs are arranged increases as the number of LEDs increases. Further, in a projector, in an optical system including an illumination device 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. From this, when a plurality of LEDs are arranged in an array, it is considered that the spatial spread of the light beam incident on the spatial light modulator increases as the number of LEDs increases.

  On the other hand, there is a limit to the angle of light that can be effectively modulated by the spatial light modulator. For this reason, it becomes difficult to use the light from the illumination device effectively as the spatial spread of the light beam incident on the spatial light modulator increases. For this reason, even if it uses the technique currently disclosed by patent document 1 and patent document 2, light may not be utilized efficiently. In particular, if the light from the light emitting unit cannot be used efficiently, a bright image may not be obtained even if a plurality of light emitting units are used, which is a problem. The present invention has been made in view of the above-described problems, and is capable of reducing the spread of a light beam and capable of supplying light with high efficiency, and a bright image can be displayed using the lighting device. An object is to provide an image display device.

  In order to solve the above-described problems and achieve the object, according to the present invention, at least two light emitting units that supply light, and the polarized light in the first vibration direction among the light from the light emitting unit are transmitted, By reflecting the polarized light in the second vibration direction substantially orthogonal to the first vibration direction, the light from the light emitting unit is separated into polarized light in the first vibration direction and polarized light in the second vibration direction. A polarization separation unit; and a reflection unit configured to reflect light traveling in the direction from the polarization separation unit toward the light emitting unit toward the polarization separation unit. The polarization separation unit transmits the first vibration transmitted through the polarization separation unit. Direction polarized light and the second vibration direction polarized light reflected by the polarization separation unit, and proceed in the direction of the irradiated surface, and further substantially uniform the intensity distribution of the luminous flux from the light emitting unit, In addition, a uniformizing unit that shapes the outer shape of the light beam into a shape that is almost similar to the irradiated surface and a polarization separation unit are combined. The light, it is possible to provide an illumination apparatus characterized by comprising a polarization conversion unit that converts either one of the first oscillation direction of the polarized light and the second vibration direction of polarized light.

  The polarized light in the first vibration direction that has entered the polarization separation unit from the light emitting unit passes through the polarization separation unit. The polarized light in the second vibration direction that has entered the polarization separation unit from the light emitting unit is reflected by the polarization separation unit. The polarization separation unit combines the polarized light in the first vibration direction that passes through the polarization separation unit and travels in a predetermined direction, and the polarized light in the second vibration direction that travels in the predetermined direction after reflection from the polarization separation unit. To do. The light combined by the polarization separation unit is converted into one of the polarized light in the first vibration direction and the polarized light in the second vibration direction by the polarization conversion unit. In this way, polarized light having a specific vibration direction can be supplied. The illuminating device can reduce the spread of the light beam emitted from the illuminating device by combining the light from each light emitting unit at the polarization separating unit, even when using a plurality of light emitting units. In addition, by providing the reflection unit, the light traveling in the direction of the light emitting unit is reflected by the reflection unit and travels in the direction of the polarization separation unit. At this time, for example, by performing polarization conversion using a phase plate, the light traveling in the direction of the polarization separation unit can travel in a predetermined direction. By converting the light synthesized by the polarization separation unit into a polarization by the polarization conversion unit, the light from the light emitting unit can be converted into polarized light having a specific vibration direction and efficiently travel in a predetermined direction. Further, the homogenizing unit makes the intensity distribution of the light beam from the light emitting unit substantially uniform, and at the same time, shapes the outer shape of the light beam into a shape substantially similar to the irradiated surface. By shaping the light flux by the homogenizing unit, the light from the light emitting unit can be incident on the irradiated surface more efficiently. As a result, it is possible to obtain an illuminating device that can reduce the spread of the light flux and can supply light with high efficiency.

  Further, according to a preferred aspect of the present invention, the uniformizing part is a rod integrator that makes the intensity distribution of light from the light emitting part substantially uniform, and the shape of the end face on the side far from the light emitting part of the rod integrator is irradiated It is desirable that the shape is substantially similar to the shape of the surface. By using the rod integrator, it is possible to efficiently guide the light from the light emitting unit to the polarization separating unit and to make the light uniform. Further, the region of the irradiated surface can be efficiently illuminated by the light beam shaped in a similar shape to the irradiated surface. Thereby, the light from a light emission part can be guide | induced to an irradiated surface efficiently and uniformly.

  According to a preferred aspect of the present invention, the uniformizing unit is a fly-eye lens that makes the light intensity distribution from the light-emitting unit substantially uniform, and the shape of the plurality of lens elements constituting the fly-eye lens is It is desirable that the shape is substantially similar to the shape of the irradiated surface. By using a fly-eye lens, light can be made uniform. Further, the region of the irradiated surface can be efficiently illuminated by the light beam shaped in a similar shape to the irradiated surface. Thereby, the light from a light emission part can be guide | induced to an irradiated surface efficiently and uniformly.

  Further, as a preferred embodiment of the present invention, the rod integrator has a tapered shape that gradually becomes thinner in the direction of the light emitting portion, and the end surface on the light emitting portion side of the rod integrator is approximately the same size as the light emitting portion. desirable. As a result, it is possible to simultaneously perform intensity equalization and light beam shaping by repeated reflection inside the rod integrator.

  As a preferred embodiment of the present invention, it is desirable that the rod integrator has an aperture reflecting mirror formed in the peripheral portion of the end face on the light emitting portion side. Thereby, the light which returns to the light emission part side can be reflected further efficiently. Therefore, light can be used effectively.

  Moreover, as a preferable aspect of the present invention, it is desirable to further include a collimator lens that makes the light from the light emitting portion substantially parallel. By using the collimator lens, the light from the light emitting unit can be efficiently guided toward the irradiated surface. In addition, by using a collimator lens, the light that travels in the direction of the light emitting unit after being reflected by the polarization separating unit or the polarization converting unit is substantially the same as when traveling from the light emitting unit to the polarization separating unit or the polarization converting unit. Follow the light path. Light traveling in the direction from the polarization separation unit or polarization conversion unit to the light emitting unit travels in substantially the same optical path as when traveling from the light emission unit to the polarization separation unit or polarization conversion unit, and efficiently enters the reflection unit. . Since the light reflected by the reflecting portion travels again toward the irradiated surface, the light can be efficiently reused by using a collimator lens. Thereby, the light from a light emission part can be utilized efficiently.

  Further, as a preferred aspect of the present invention, a rod integrator is further provided between the light emitting unit and the polarization separating unit, and the rod integrator has an aperture reflecting mirror formed in a peripheral portion of the end surface on the light emitting unit side. desirable. Thereby, the light which returns to the light emission part side can be reflected further efficiently. Therefore, light can be used effectively.

  Moreover, as a preferable aspect of the present invention, it is desirable that the polarization conversion unit includes a polarization conversion element array provided at a position substantially coincident with a position where an image of the light emitting unit is formed. Thereby, the light combined by the polarization separation unit can be converted into one of the polarized light in the first vibration direction and the polarized light in the second vibration direction.

  Moreover, as a preferable aspect of the present invention, it is desirable that the polarization conversion unit includes a reflective polarizing plate and a phase plate provided on the incident side of the reflective polarizing plate. The reflective polarizing plate transmits polarized light having a specific vibration direction and reflects polarized light having another vibration direction different from the specific vibration direction. The light reflected by the reflective polarizing plate is reflected by the reflecting portion and then travels again toward the reflective polarizing plate. For example, by allowing light to pass through a λ / 4 phase plate that is a phase plate twice, the vibration direction of the light can be rotated by 90 degrees. By passing the λ / 4 phase plate twice, polarized light in the first vibration direction and polarized light in the second vibration direction can be converted into each other. Thereby, the light combined by the polarization separation unit can be converted into one of the polarized light in the first vibration direction and the polarized light in the second vibration direction.

  Furthermore, according to the present invention, it is possible to provide an image display device characterized by including the illumination device described above and a spatial light modulation device that modulates light from the illumination device in accordance with an image signal. By providing the illumination device described above, it is possible to supply light with high efficiency to the spatial light modulation device to be illuminated. Thereby, an image display device capable of displaying a bright image with high light utilization efficiency can be obtained.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1-1 shows a schematic configuration of the illumination device 100 according to the first embodiment of the present invention. The lighting device 100 includes an LED 101 that is a first light emitting unit and an LED 102 that is a second light emitting unit. The LEDs 101 and 102 are surface-emitting light sources that mainly emit light from the surface of the chip. The LEDs 101 and 102 supply light in the direction of the reflective polarizing plate 108. A collimator lens CL1 and a λ / 4 phase plate 105 are provided in the optical path between the LED 101 and the reflective polarizing plate 108. In the optical path between the LED 102 and the reflective polarizing plate 108, a collimator lens CL2 and a λ / 4 phase plate 106 are provided. The collimator lenses CL1 and CL2 make the light from the LEDs 101 and 102 substantially parallel, respectively. The λ / 4 phase plates 105 and 106 are phase plates provided between the LEDs 101 and 102 and the reflective polarizing plate 108, respectively.

  The reflective polarizing plate 108 transmits the polarized light in the first vibration direction out of the light from the LEDs 101 and 102 and reflects the polarized light in the second vibration direction, so that the light from the LEDs 101 and 102 is first. A polarization separation unit that separates the polarized light in the vibration direction and the polarized light in the second vibration direction. The polarized light in the first vibration direction is, for example, p-polarized light. The polarized light in the second vibration direction is polarized light in the vibration direction substantially orthogonal to the first vibration direction, and is, for example, s-polarized light. As the reflective polarizing plate 108, for example, a wire grid type polarizing plate can be used. The polarization separation unit is not limited to the case where the reflective polarizing plate 108 is used, and for example, a polarization beam splitter having a polarization separation film may be used.

  A mirror 109 is provided on the opposite side of the reflective polarizing plate 108 from the side on which the LED 102 is provided. The mirror 109 transmits the reflection type polarizing plate 108 and reflects the light traveling in the direction different from the illumination direction L from the reflection type polarizing plate 108 toward the reflection type polarizing plate 108. Moreover, LED101,102 has the reflection parts 103 and 104, respectively. The reflection parts 103 and 104 are metal electrodes formed of a highly reflective metal member. The reflector 103 reflects light traveling from the reflective polarizing plate 108 toward the LED 101 toward the reflective polarizing plate 108. The reflection unit 104 reflects light traveling from the reflective polarizing plate 108 toward the LED 102 toward the reflective polarizing plate 108.

  The LED 101 is disposed around the optical axis AX along the illumination direction L. The LED 102 and the mirror 109 are disposed around an axis BX that is substantially perpendicular to the optical axis AX. The reflective polarizing plate 108 is disposed so as to be inclined by approximately 45 degrees with respect to both the optical axis AX and the axis BX. In addition, the reflective polarizing plate 108 is provided with the position where the optical axis AX and the axis BX intersect substantially as a center.

  A collimator lens CL3 and a rod integrator 111 are provided on the side opposite to the side where the LED 101 is present when viewed from the reflective polarizing plate 108 on the optical axis AX. The collimator lens CL3 guides light traveling in the illumination direction L, which is the direction of the irradiated surface I, from the reflective polarizing plate 108 to the rod integrator 111. The rod integrator 111 is a uniformizing unit that substantially uniforms the intensity distribution of the light flux from the LEDs 101 and 102 and shapes the outer shape of the light flux into a shape that is substantially similar to the irradiated surface I.

  The rod integrator 111 is made of a transparent glass member having a rectangular parallelepiped shape. The light incident on the rod integrator 111 travels inside the rod integrator 111 while repeating total reflection at the interface between the glass member and air. Thereby, the rod integrator 111 makes the light intensity distribution from the LEDs 101 and 102 substantially uniform. Further, the shape of the end surface of the rod integrator 111 far from the LEDs 101 and 102 is substantially similar to the shape of the irradiated surface I. The rod integrator 111 shapes the light beam at an end surface that is substantially similar to the irradiated surface I. By shaping the light beam according to the shape of the irradiated surface I, the illumination device 100 can efficiently illuminate the region of the irradiated surface I.

  In the rod integrator 111, an aperture reflection mirror M is formed in the peripheral portion of the end face on the LED 101, 102 side. Light from the LEDs 101 and 102 enters the rod integrator 111 from the opening of the aperture reflection mirror M. The aperture reflection mirror M reflects light traveling in the direction of the aperture reflection mirror M from the polarization conversion unit 112 described later in the direction of the polarization conversion unit 112.

  The rod integrator 111 is not limited to a glass member but may be a hollow structure whose inner surface is a reflective surface. In the case of a rod integrator having an inner surface as a reflecting surface, light incident on the rod integrator travels inside the rod integrator while being repeatedly reflected on the reflecting surface. Further, the rod integrator may be configured to combine a glass member and a reflecting surface.

  A polarization converter 112 is provided on the end surface of the rod integrator 111 far from the LEDs 101 and 102. The polarization conversion unit 112 converts the light combined by the reflective polarizing plate 108 serving as a polarization separation unit into one of the polarized light in the first vibration direction and the polarized light in the second vibration direction. For example, the polarization conversion unit 112 converts the light synthesized by the reflective polarizing plate 108 into p-polarized light that is polarized light in the first vibration direction and emits it. As illustrated in FIG. 1B, the polarization conversion unit 112 includes a reflective polarizing plate 122 and a λ / 4 phase plate 121 that is a phase plate provided on the incident side of the reflective polarizing plate 122. The operation of the polarization conversion unit 112 will be described later. As shown in FIG. 1A, the polarization conversion unit 112 may be provided to be joined to the rod integrator 111 or may be provided apart from the rod integrator 111.

  As the reflective polarizing plate 122 provided in the polarization conversion unit 112, a wire grid type polarizing plate can be used similarly to the reflective polarizing plate 108 which is a polarization separation unit. The wire grid type polarizing plate can use a structure 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. The wire grid type polarizing plate 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 type polarizing plate so that the wire is substantially perpendicular to the vibration direction of the polarized light in the specific vibration direction, only the polarized light in the specific vibration direction can be transmitted. Since the wire grid type polarizing plate is relatively inexpensive among the members used as the polarization separation element, the illumination device 100 can be made inexpensive by using the wire grid type polarizing plate.

  The LED 101 and the LED 102 supply light including p-polarized light and s-polarized light. The light from the LED 101 passes through the collimator lens CL 1 and the λ / 4 phase plate 105 and then enters the reflective polarizing plate 108. The collimator lens CL1 illuminates the reflective polarizing plate 108 in a telecentric manner so that the principal ray of light emitted from the collimator lens CL1 is substantially parallel to the optical axis AX. By using the collimator lens CL1, the light from the LED 101 can be efficiently guided to the reflective polarizing plate.

  Of the light that has passed through the collimator lens CL1 and the λ / 4 phase plate 105 and entered the reflective polarizing plate 108, the p-polarized light passes through the reflective polarizing plate 108 and then proceeds in the illumination direction L. On the other hand, the s-polarized light out of the light incident on the reflective polarizing plate 108 after passing through the collimator lens CL1 and the λ / 4 phase plate 105 is reflected by the reflective polarizing plate 108 and then toward the mirror 109. proceed.

  The s-polarized light traveling in the direction of the mirror 109 is reflected by the mirror 109 and then travels again in the direction of the reflective polarizing plate 108. The s-polarized light traveling in the direction of the reflective polarizing plate 108 is reflected by the reflective polarizing plate 108 and travels in the direction of the LED 101. The s-polarized light traveling in the direction of the LED 101 passes through the λ / 4 phase plate 105 and is converted into circularly polarized light. The light converted into circularly polarized light passes through the collimator lens CL1 and then enters the LED 101.

  The light traveling in the direction from the reflective polarizing plate 108 to the LED 101 passes through the collimator lens CL1 and travels in substantially the same optical path as traveling from the LED 101 to the reflective polarizing plate 108. The light traveling in the direction from the reflective polarizing plate 108 to the LED 101 efficiently enters the LED 101 by traveling in substantially the same optical path as traveling from the LED 101 to the reflective polarizing plate 108. The light incident on the LED 101 from the reflective polarizing plate 108 is reflected by the reflecting portion 103 and travels again toward the reflective polarizing plate 108. By using the collimator lens CL1, light can be reused efficiently and the light from the LED 101 can be used efficiently.

  The circularly polarized light incident on the LED 101 is incident on the λ / 4 phase plate 105 again after being reflected by the reflector 103. The λ / 4 phase plate 105 converts circularly polarized light into p-polarized light and makes it incident on the reflective polarizing plate 108. In this way, by allowing light to pass through the λ / 4 phase plate 105 twice, the vibration direction of the light can be rotated by 90 degrees. The p-polarized light incident on the reflective polarizing plate 108 passes through the reflective polarizing plate 108 and travels in the illumination direction L.

  Thus, the p-polarized light of the light from the LED 101 remains as it is, and the s-polarized light is converted into p-polarized light and then enters the rod integrator 111. The light incident on the rod integrator 111 passes through the rod integrator 111 and then enters the polarization converter 112. Light incident on the rod integrator 111 from the LED 101 is p-polarized light. For this reason, the light that has entered the polarization conversion unit 112 from the LED 101 passes through the reflective polarizing plate 122 of the polarization conversion unit 112 and is emitted from the illumination device 100. The p-polarized light from the LED 101 is emitted from the illumination device 100 by passing through each component on the optical axis AX. The s-polarized light from the LED 101 is reflected once by the reflection unit 103 and the mirror 109, reflected twice by the reflection type polarizing plate 108, and transmitted once by the reflection type polarizing plate 108 and the polarization conversion unit 112. Thereafter, the light is emitted from the lighting device 100.

  The light from the LED 102 passes through the collimator lens CL2 and the λ / 4 phase plate 106 and then enters the reflective polarizing plate 108. The light from the LED 102 can be efficiently guided to the reflective polarizing plate 108 by the action of the collimator lens CL2. Of the light that has passed through the collimator lens CL2 and the λ / 4 phase plate 106 and entered the reflective polarizing plate 108, the s-polarized light is reflected by the reflective polarizing plate 108 and travels in the illumination direction L.

  Of the light that has passed through the collimator lens CL2 and the λ / 4 phase plate 106 and entered the reflective polarizing plate 108, the p-polarized light passes through the reflective polarizing plate 108 and then travels in the direction of the mirror 109. The p-polarized light traveling in the direction of the mirror 109 is reflected by the mirror 109 and enters the reflective polarizing plate 108 again. The p-polarized light incident on the reflective polarizing plate 108 passes through the reflective polarizing plate 108 and travels toward the LED 102. By the action of the collimator lens CL2, similarly to the case of the collimator lens CL1, light traveling from the reflective polarizing plate 108 toward the LED 102 can be efficiently incident on the LED 102.

  The p-polarized light traveling in the direction of the LED 102 is converted into s-polarized light by passing through the λ / 4 phase plate 106 twice before being reflected by the reflecting portion 104 and entering the reflective polarizing plate 108. The s-polarized light incident on the reflective polarizing plate 108 is reflected by the reflective polarizing plate 108 and travels in the illumination direction L. As described above, the s-polarized light out of the light from the LED 102 is directly converted into the p-polarized light and then incident on the rod integrator 111.

  Light incident on the rod integrator 111 from the LED 102 is s-polarized light. For this reason, the light incident on the polarization conversion unit 112 from the LED 102 is reflected by the reflective polarizing plate 122 of the polarization conversion unit 112. The light reflected by the reflective polarizing plate 122 travels in the direction of the aperture reflection mirror M. The light that has entered the aperture reflection mirror M from the reflective polarizing plate 122 is reflected by the aperture reflection mirror M, and then travels again toward the polarization converter 112.

  The s-polarized light reflected by the reflective polarizing plate 122 passes through the λ / 4 phase plate 121 (see FIG. 1-2) twice before being reflected by the aperture reflection mirror M and entering the polarization conversion unit 112 again. Is converted into p-polarized light. In this way, the polarization conversion unit 112 converts the s-polarized light out of the light synthesized by the reflective polarizing plate 108, which is a polarization separation unit, into p-polarized light. The light converted into p-polarized light passes through the reflective polarizing plate 122 and is emitted from the illumination device 100. The p-polarized light from the LED 102 is reflected once by the mirror 109, the reflection unit 104, the reflection type polarizing plate 108, the polarization conversion unit 112, and the aperture reflection mirror M, and twice by the reflection type polarizing plate 108. After passing through the unit 112 once, the light is emitted from the lighting device 100. The s-polarized light from the LED 102 passes through the reflection type polarizing plate 108, the polarization conversion unit 112, and the aperture reflection mirror M once, and passes through the polarization conversion unit 112 once, and then is emitted from the illumination device 100. To do.

  For example, when the illumination target is a liquid crystal type spatial light modulation device of a projector, a black matrix portion that blocks light is formed between openings that transmit light to the liquid crystal. In this embodiment, since the rod integrator 111 can be arranged close to the irradiated surface I, the light reflected by the black matrix portion may be returned to the rod integrator 111. If the light reflected by the black matrix portion can be reused, the light utilization efficiency can be further improved.

  The illuminating device 100 synthesizes the light from the LEDs 101 and 102 with the reflective polarizing plate 108 so that the light from the LEDs 101 and 102 travels to substantially the same irradiated surface I. For this reason, even when two LEDs 101 and 102 are used, the spread of the light beam emitted from the illumination device 100 can be reduced. The illuminating device 100 converts the light from the LEDs 101 and 102 into polarized light in the first vibration direction by using the reflective polarizing plate 108 that is a polarization separation unit and the polarization conversion unit 112, and the illumination direction L Can proceed to. For this reason, the illuminating device 100 can supply the light from LED101,102 efficiently.

  The light from the LEDs 101 and 102 can be incident on the irradiated surface I more efficiently by shaping the light flux by the rod integrator 111 that is a uniformizing unit. As a result, it is possible to reduce the spread of the luminous flux and to supply light with high efficiency. For example, when the illumination device 100 is used in a projector, the spread of the light beam incident on the spatial light modulation device can be reduced, so that the illumination light from the illumination device 100 can be efficiently modulated by the spatial light modulation device.

  The polarization conversion unit 112 is not limited to the configuration that converts the light combined by the reflective polarizing plate 108 that is a polarization separation unit into p-polarized light that is polarized light in the first vibration direction, but the second vibration. A configuration may be adopted in which the light is converted into s-polarized light that is polarized light in the direction. In this case, the polarization converter 112 uses a reflective polarizing plate 122 that transmits s-polarized light that is polarized light in the second vibration direction and reflects p-polarized light that is polarized light in the first vibration direction. It is done.

  Further, the polarized light in the first vibration direction is s-polarized light, the polarized light in the second vibration direction is p-polarized light, and the s-polarized light is transmitted through the reflective polarizing plate 108 that is a polarization separation unit, and p-polarized light. It is good also as reflecting. In this case, the reflective polarizing plate 108 combines the s-polarized light from the LED 101 that has passed through the reflective polarizing plate 108 and the p-polarized light from the LED 102 that has been reflected by the reflective polarizing plate 108 and proceeds in the illumination direction L. Let

  FIG. 2 shows a schematic configuration of a lighting device 200 according to a modification of the present embodiment. In this aspect and the aspect described below, the same parts as those of the lighting device 100 are denoted by the same reference numerals, and redundant description is omitted. The illumination device 200 of the present modification includes rod integrators 213 and 214 provided between the LEDs 101 and 102 that are light emitting units and the reflective polarizing plate 108 that is a polarization separation unit, respectively.

  The rod integrators 213 and 214 are formed of a transparent glass member having a rectangular parallelepiped shape. The light incident on the rod integrators 213 and 214 travels through the rod integrators 213 and 214 while repeating total reflection at the interface between the glass member and air. Further, the rod integrators 213 and 214 are formed with aperture reflection mirrors M1 and M2 in the peripheral portion of the end face on the LED 101 and 102 side, similarly to the rod integrator 111 which is a uniformizing portion. The aperture reflection mirrors M1 and M2 are reflection portions that reflect light traveling from the reflective polarizing plate 108 toward the LEDs 101 and 102 toward the reflective polarizing plate 108.

  The shapes of the end surfaces of the rod integrators 213 and 214 on which the aperture reflection mirrors M1 and M2 are formed are similar to the shapes of the LEDs 101 and 102 at an enlargement magnification. That is, the end surfaces of the rod integrators 213 and 214 are configured to be larger than the LEDs 101 and 102. For example, when the LEDs 101 and 102 are in close contact with the rod integrators 213 and 214, aperture reflection mirrors M1 and M2 are formed in the area around the LEDs 101 and 102.

  Thereby, even when the LEDs 101 and 102 have a low reflectance, light traveling from the reflective polarizing plate 108 toward the LEDs 101 and 102 can be reflected from the aperture reflection mirrors M1 and M2 toward the reflective polarizing plate 108. Therefore, light can be used effectively. The functions of the rod integrators 213 and 214 are not for shaping the light beam but for improving the light reuse efficiency. Therefore, the shape of the end surfaces of the rod integrators 213 and 214 on the side far from the LEDs 101 and 102 does not have to be similar to the irradiated surface I, and may be any shape. Further, the rod integrators 213 and 214 may be relatively short as long as the light traveling from the reflective polarizing plate 108 toward the LEDs 101 and 102 can be reflected by the aperture reflection mirrors M1 and M2.

  The rod integrators 213 and 214 are not limited to those made of a glass member, but may have a hollow structure whose inner surface is made of a reflective surface. In the case of a rod integrator having an inner surface as a reflecting surface, light incident on the rod integrator travels inside the rod integrator while being repeatedly reflected on the reflecting surface. Further, the rod integrator may be configured to combine a glass member and a reflecting surface.

  FIG. 3 shows a schematic configuration of a lighting apparatus 300 according to Embodiment 2 of the present invention. The illumination device 300 according to the present embodiment includes fly-eye lenses 301 and 302 that are uniformizing units, and a polarization conversion element array 315 that is a polarization conversion unit. The fly-eye lenses 301 and 302 and the polarization conversion element array 315 are provided on the optical axis AX in the optical path between the reflective polarizing plate 108 and the irradiated surface I. Two collimator lenses CL3 and CL4 are provided between the polarization conversion element array 315 and the irradiated surface I.

  The fly-eye lenses 301 and 302 are configured by arranging a plurality of lens elements in a matrix on a surface substantially perpendicular to the optical axis AX. The fly-eye lenses 301 and 302 are uniformizing portions that make the intensity distribution of the light flux from the LEDs 101 and 102 substantially uniform and shape the outer shape of the light flux into a shape that is substantially similar to the irradiated surface I. The fly-eye lenses 301 and 302 are provided between the reflective polarizing plate 108 that is a polarization separation unit and the polarization conversion element array 315 that is a polarization conversion unit in order to make the light intensity distribution from the LEDs 101 and 102 substantially uniform. Is provided.

  The shapes of the plurality of lens elements constituting the fly-eye lenses 301 and 302 are substantially similar to the shape of the irradiated surface I. That is, the aspect ratio of each lens element and the aspect ratio of the irradiated surface I are the same. The fly-eye lenses 301 and 302 shape a light beam in a lens element having a similar shape to the irradiated surface I. By shaping the light beam according to the shape of the irradiated surface I, the illumination device 100 can efficiently illuminate the region of the irradiated surface I.

  FIG. 4 shows a cross-sectional configuration of a main part of the polarization conversion element array 315. The polarization conversion element array 315 converts the light synthesized by the reflective polarizing plate 108, which is a polarization separation unit, into one of polarized light in the first vibration direction and polarized light in the second vibration direction. Part. For example, the polarization conversion element array 315 converts the light synthesized by the reflective polarizing plate 108 into p-polarized light that is polarized light in the first vibration direction. The polarization conversion element array 315 is provided at a position that substantially coincides with the position at which the images of the LEDs 101 and 102 are formed by the fly-eye lenses 301 and 302.

  The polarization conversion element array 315 is a plate-like structure configured by bonding prism bodies 401 represented by diamonds in the cross-sectional configuration illustrated in FIG. Polarizing films 402 and reflecting films 403 are alternately formed between the prism bodies 401. A λ / 2 phase plate 404 is provided at a position corresponding to the reflective film 403 on the exit surface of the polarization conversion element array 315. The λ / 2 phase plate 404 rotates the incident light by 90 degrees and emits the light. The polarization conversion element array 315 is configured by arranging polarization conversion elements each including a polarization film 402, a reflection film 403, and a λ / 2 phase plate 404 in an array.

  The polarizing film 402 transmits the p-polarized light Lo1 out of the light Li incident on the polarization conversion element array 315. The p-polarized light Lo1 transmitted through the polarizing film 402 is emitted from the polarization conversion element array 315 as it is. The polarizing film 402 reflects the s-polarized light Lo2 in the light Li incident on the polarization conversion element array 315. The reflective film 403 reflects the s-polarized light reflected by the polarizing film 402. The s-polarized light travels while being shifted so as to take an optical path different from that of the p-polarized light by the action of the polarizing film 402 and the reflecting film 403. Then, the s-polarized light that has traveled by shifting the optical path is incident on the λ / 2 phase plate 404 as it is.

  The λ / 2 phase plate 404 converts s-polarized light into p-polarized light by converting the vibration direction of the s-polarized light from the reflective film 403 by 90 °. The light converted into p-polarized light by the λ / 2 phase plate 404 is emitted from the polarization conversion element array 315. In this manner, the polarization conversion element array 315 converts the s-polarized light out of the light synthesized by the reflective polarizing plate 108 serving as a polarization separation unit into p-polarized light. By providing the polarization conversion element array 315 at a position that substantially coincides with the position at which the images of the LEDs 101 and 102 are formed, the light from the reflective polarizing plate 108 can be efficiently polarized.

  The fly-eye lens 302 is preferably configured to be able to collect light on a portion of the polarization conversion element array 315 where the polarizing film 402 is provided. Thereby, the polarization conversion of light can be efficiently performed in the polarization conversion element array 315. The fly-eye lens 302 may be provided on the incident surface of the polarization conversion element array 315. The collimator lenses CL3 and CL4 guide light traveling in the illumination direction L from the polarization conversion element array 315 to the irradiated surface I. As described above, the illumination device 200 according to the present embodiment can reduce the spread of the light flux and can supply light with high efficiency, similarly to the illumination device 100 described above.

  Note that, as in the illumination device 500 illustrated in FIG. 5, rod integrators 213 and 214 may be further provided between the LEDs 101 and 102 and the reflective polarizing plate 108 that is a polarization separation unit. Thereby, even when the LEDs 101 and 102 have a low reflectance, light traveling from the reflective polarizing plate 108 toward the LEDs 101 and 102 can be reflected from the aperture reflection mirrors M1 and M2 toward the reflective polarizing plate 108.

  FIG. 6 shows a schematic configuration of a lighting apparatus 600 according to Embodiment 3 of the present invention. The illumination device 600 of the present embodiment is characterized in that rod integrators 613 and 614 that are uniformizing portions are provided between the LEDs 101 and 102 and the reflective polarizing plate 108. The rod integrator 613 is provided in the optical path between the LED 101 and the collimator lens CL1. The rod integrator 614 is provided in the optical path between the LED 102 and the λ / 4 phase plate 106.

  The rod integrators 613 and 614 are uniforming sections that make the intensity distribution of the light flux from the LEDs 101 and 102 substantially uniform and shape the outer shape of the light flux into a shape that is substantially similar to the irradiated surface I. The rod integrators 613 and 614 are made of a transparent glass member having a tapered shape. The light incident on the rod integrators 613 and 614 travels inside the rod integrators 613 and 614 while repeating total reflection at the interface between the glass member and air. Accordingly, the rod integrators 613 and 614 make the light intensity distribution from the LEDs 101 and 102 substantially uniform.

  The rod integrators 613 and 614 have a tapered shape that gradually decreases in the direction of the LEDs 101 and 102. One end surface of the rod integrators 613 and 614 on the LED 101 and 102 side is approximately the same size as the LEDs 101 and 102. Further, the shape of the end surfaces of the rod integrators 613 and 614 far from the LEDs 101 and 102 is substantially similar to the shape of the irradiated surface I. Specifically, the aspect ratio of the irradiated surface I and the aspect ratio of the other end surface are the same. The rod integrators 613 and 614 shape the light beam at the end surface that is substantially similar to the irradiated surface I. By shaping the light beam according to the shape of the irradiated surface I, the illumination device 600 can efficiently illuminate the region of the irradiated surface I. It is desirable that the rod integrators 613 and 614 have a sufficient length in order to improve the uniformity of the intensity distribution of the emitted light beam.

  The rod integrators 613 and 614 are not limited to those made of a glass member, but may have a hollow structure whose inner surface is made of a reflecting surface. In the case of a rod integrator having an inner surface as a reflecting surface, light incident on the rod integrator travels inside the rod integrator while being repeatedly reflected on the reflecting surface. Further, the rod integrator may be configured to combine a glass member and a reflecting surface.

  The polarization conversion element array 315 which is a polarization conversion unit is provided on the optical axis AX in the optical path between the reflective polarizing plate 108 which is a polarization separation unit and the irradiated surface I. A collimator lens CL3 is provided between the reflective polarizing plate 108 and the polarization conversion element array 315. A collimator lens CL4 is provided between the polarization conversion element array 315 and the irradiated surface I.

  The polarization conversion element array 315 is provided at a position that substantially coincides with the position at which the images of the LEDs 101 and 102 are formed by the collimator lenses CL1, CL2, and CL3. By providing the polarization conversion element array 315 at the position where the images of the LEDs 101 and 102 are formed, the light from the reflective polarizing plate 108 can be efficiently polarized and converted. The collimator lens CL4 guides light traveling in the illumination direction L from the polarization conversion element array 315 to the irradiated surface I. As described above, the illumination device 600 according to the present embodiment can reduce the spread of the light flux and can supply light with high efficiency similarly to the illumination device 100 described above.

  FIG. 7 shows a schematic configuration of a lighting apparatus 700 according to a modification of the present embodiment. The illumination device 700 of this modification is characterized in that aperture reflectors M1 and M2 are provided in rod integrators 713 and 714, respectively, which are uniformizing sections. The rod integrator 713 is provided in the optical path between the LED 101 and the collimator lens CL1. The rod integrator 714 is provided in the optical path between the LED 102 and the λ / 4 phase plate 106.

  The rod integrators 713 and 714 are made of a transparent glass member having a rectangular parallelepiped shape. The light incident on the rod integrators 713 and 714 travels inside the rod integrators 713 and 714 while repeating total reflection at the interface between the glass member and air. Accordingly, the rod integrators 713 and 714 make the light intensity distribution from the LEDs 101 and 102 substantially uniform. Further, the shape of the end surfaces of the rod integrators 713 and 714 on the side far from the LEDs 101 and 102 is substantially similar to the shape of the irradiated surface I. Also in this modification, it is desirable that the rod integrators 713 and 714 have a sufficient length in order to improve the uniformity of the intensity distribution of the emitted light beam.

  In the rod integrators 713 and 714, similarly to the rod integrator 111 of the first embodiment, aperture reflection mirrors M1 and M2 are formed in the peripheral portion of the end face on the LED 101 and 102 side. The aperture reflection mirrors M1 and M2 are reflection portions that reflect light traveling from the reflective polarizing plate 108 toward the LEDs 101 and 102 toward the reflective polarizing plate 108. The shapes of the end surfaces of the rod integrators 713 and 714 on which the aperture reflection mirrors M1 and M2 are formed are similar to the shapes of the LEDs 101 and 102 at the magnification. That is, the end surfaces of the rod integrators 713 and 714 are configured to be larger than the LEDs 101 and 102. For example, when the LEDs 101 and 102 are in close contact with the rod integrators 713 and 714, the aperture reflection mirrors M1 and M2 are formed in the area around the LEDs 101 and 102.

  Thereby, even when the LEDs 101 and 102 have a low reflectance, light traveling from the reflective polarizing plate 108 toward the LEDs 101 and 102 can be reflected from the aperture reflection mirrors M1 and M2 toward the reflective polarizing plate 108. Therefore, light can be used effectively. The rod integrators 713 and 714 are not limited to a rectangular parallelepiped shape. Similar to the rod integrators 613 and 614, a configuration having a tapered shape may be employed.

  FIG. 8 shows a schematic configuration of a projector 800 that is an image display apparatus according to Embodiment 4 of the present invention. The projector 800 is a so-called three-plate projector provided with three liquid crystal type spatial light modulators 172R, 172G, and 172B. The projector 800 includes an R light illumination device 170R, a G light illumination device 170G, and a B light illumination device 170B. Each of the lighting devices 170R, 170G, and 170B has the same configuration as that of the lighting device 100 of the first embodiment.

  The R light illumination device 170R includes two R light LEDs 171R. The LED 171R for R light supplies R light. The R light illumination device 170R converts the R light from the R light LED 171R into polarized light having a specific vibration direction, for example, p-polarized light, and proceeds in the direction of the liquid crystal spatial light modulator 172R, which is a predetermined direction. Let The liquid crystal spatial light modulator 172R is a transmissive liquid crystal display device that modulates R light according to an image signal. The p-polarized light incident on the liquid crystal spatial light modulator 172R is converted into s-polarized light by modulation. The R light converted into s-polarized light by the liquid crystal type spatial light modulator 172R enters the cross dichroic prism 173.

  The G light illumination device 170G includes two G light LEDs 171G. The G light LED 171G supplies G light. The G light illumination device 170G converts the G light from the G light LED 171G into polarized light having a specific vibration direction, for example, p-polarized light, and proceeds in the direction of the liquid crystal type spatial light modulator 172G which is a predetermined direction. Let The liquid crystal spatial light modulator 172G is a transmissive liquid crystal display device that modulates G light according to an image signal. The p-polarized light incident on the liquid crystal spatial light modulator 172G is converted into s-polarized light by modulation. The G light converted into s-polarized light by the liquid crystal spatial light modulator 172G enters the cross dichroic prism 173 from a surface different from the R light.

  The B light illumination device 170B includes two B light LEDs 171B. The B light LED 171B supplies B light. The B light illumination device 170B converts the B light from the B light LED 171B into polarized light having a specific vibration direction, for example, p-polarized light, and proceeds in the direction of the liquid crystal spatial light modulator 172B, which is a predetermined direction. Let The liquid crystal spatial light modulator 172B is a transmissive liquid crystal display device that modulates B light according to an image signal. The p-polarized light incident on the liquid crystal type spatial light modulator 172B is converted into s-polarized light by modulation. The B light converted into the s-polarized light by the liquid crystal type spatial light modulator 172B enters the cross dichroic prism 173 from a plane different from the R light and the G light.

  A cross dichroic prism 173 that is a color synthesis optical system includes two dichroic films 173a and 173b. The dichroic films 173a and 173b are arranged orthogonal to the X shape. The dichroic film 173a reflects R light and transmits G light. The dichroic film 173b reflects B light and transmits G light. In this manner, the cross dichroic prism 173 combines the R light, G light, and B light modulated by the liquid crystal type spatial light modulators 172R, 172G, and 172B, respectively. The projection optical system 174 projects the light combined by the cross dichroic prism 173 onto the screen 175.

  The dichroic films 173a and 173b are usually excellent in the reflection characteristics of s-polarized light. For this reason, it is desirable that the R light and B light to be reflected by the dichroic films 173a and 173b are incident on the cross dichroic prism 173 as s-polarized light. Further, it is desirable that the G light to be transmitted through the dichroic films 173a and 173b becomes p-polarized light and enters the cross dichroic prism 173. In order to make the G light converted into the s-polarized light enter the cross dichroic prism 173, for example, a λ / 2 phase plate may be provided between the liquid crystal type spatial light modulator 172G and the cross dichroic prism 173.

  By using the color light illumination devices 170R, 170G, and 170B, the projector 800 can supply light to the liquid crystal type spatial light modulation devices 172R, 172G, and 172B, which are illumination targets, with high efficiency. As a result, a bright image can be displayed with high light utilization efficiency. Each of the color light illumination devices 170R, 170G, and 170B may have the same configuration as the illumination device 100 of the first embodiment, and may have the same configuration as the other illumination devices of the second and third embodiments.

  In addition, although the illuminating device of each said Example uses LED as a light emission part, it is not restricted to this. Instead of the LED, other solid light emitting elements such as an EL element and a semiconductor laser may be used. The spatial light modulation device used for the projector 800 is not limited to a transmissive liquid crystal display device, and a reflective liquid crystal display device may be used. Furthermore, the image display device provided with the illumination device is not limited to the projector, and may be a display that directly views light modulated by the spatial light modulation device, for example.

  As described above, the illumination device according to the present invention is useful when used in a projector, and is particularly suitable for a projector that modulates polarized light in a specific vibration direction.

The figure which shows schematic structure of the illuminating device which concerns on Example 1 of this invention. The figure which shows the structure of a polarization conversion part. FIG. 6 is a diagram illustrating a schematic configuration of a lighting device according to a modification of the first embodiment. The figure which shows schematic structure of the illuminating device which concerns on Example 2 of this invention. The figure which shows the principal part cross-section structure of a polarization conversion element array. The figure which shows the structure which provides a rod integrator between a light emission part and a polarization separation part. The schematic structure of the illuminating device which concerns on Example 3 of this invention is shown. FIG. 10 is a diagram illustrating a schematic configuration of a lighting device according to a modification of Example 3; FIG. 10 is a diagram illustrating a schematic configuration of a projector according to a fourth embodiment of the invention.

Explanation of symbols

  100 Illuminator, 101, 102 LED, 103, 104 Reflector, 105, 106 λ / 4 phase plate, 108 Reflective polarizing plate, 109 Mirror, 111 Rod integrator, 112 Polarization converter, CL1, CL2 Collimator lens, M aperture Reflective mirror, AX optical axis, BX axis, L illumination direction, 121 λ / 4 phase plate, 122 reflective polarizing plate, 200 illumination device, 213, 214 Rod integrator, CL3 collimator lens, M1, M2 aperture reflective mirror, 300 illumination Apparatus 301, 302 fly-eye lens, 315 polarization conversion element array, CL4 collimator lens, 401 prism body, 402 polarization film, 403 reflection film, 404 λ / 2 phase plate, 500 illumination apparatus, 600 illumination apparatus, 613, 614 rod Integrator, 700 Illumination device, 713, 714 Rod integrator, 800 projector, 170R R light illumination device, 170G G light illumination device, 170B B light illumination device, 172R, 172G, 172B Liquid crystal type spatial light modulation device, 173 Cross dichroic prism, 173a, 172b Dichroic film, 174 projection optical system, 175 screen

Claims (10)

At least two light emitting units for supplying light;
Light from the light emitting unit is transmitted by transmitting polarized light in the first vibration direction out of light from the light emitting unit and reflecting polarized light in the second vibration direction substantially orthogonal to the first vibration direction. Is separated into polarized light in the first vibration direction and polarized light in the second vibration direction;
A reflection part that reflects light traveling in the direction of the light emitting part from the polarization separation part to the direction of the polarization separation part, and
The polarization separation unit combines the polarized light in the first vibration direction transmitted through the polarization separation unit and the polarized light in the second vibration direction reflected by the polarization separation unit, and Go in the direction,
Furthermore, a uniformizing unit for making the intensity distribution of the light beam from the light emitting unit substantially uniform and shaping the outer shape of the light beam into a shape substantially similar to the irradiated surface;
And a polarization conversion unit that converts the light combined by the polarization separation unit into one of the polarized light in the first vibration direction and the polarized light in the second vibration direction. apparatus. The uniformizing unit is a rod integrator that makes the intensity distribution of light from the light emitting unit substantially uniform,
The lighting device according to claim 1, wherein a shape of an end surface of the rod integrator far from the light emitting unit is substantially similar to a shape of the irradiated surface. The uniformizing unit is a fly-eye lens that makes the intensity distribution of light from the light emitting unit substantially uniform,
The illumination device according to claim 1, wherein the shape of the plurality of lens elements constituting the fly-eye lens is substantially similar to the shape of the irradiated surface. The rod integrator has a tapered shape that gradually becomes thinner in the direction of the light emitting part,
The lighting device according to claim 2, wherein an end surface of the rod integrator on the light emitting unit side is substantially the same size as the light emitting unit.   The illumination apparatus according to claim 2, wherein the rod integrator has an aperture reflection mirror formed in a peripheral portion of an end surface on the light emitting unit side.   The illumination device according to claim 1, further comprising a collimator lens that makes light from the light emitting unit substantially parallel. A rod integrator is further provided between the light emitting unit and the polarization separating unit,
4. The illumination device according to claim 2, wherein the rod integrator has an aperture reflection mirror formed in a peripheral portion of an end surface on the light emitting unit side.   The said polarization conversion part is equipped with the polarization conversion element array provided in the position substantially corresponded with the position where the image of the said light emission part is formed, The Claim 1 characterized by the above-mentioned. Lighting device.   The illumination device according to claim 1, wherein the polarization conversion unit includes a reflective polarizing plate and a phase plate provided on an incident side of the reflective polarizing plate. The lighting device according to any one of claims 1 to 9,
An image display device comprising: a spatial light modulation device that modulates light from the illumination device according to an image signal.

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