WO2003001277A1 - Systeme d'eclairage optique et projecteur - Google Patents
Systeme d'eclairage optique et projecteur Download PDFInfo
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- WO2003001277A1 WO2003001277A1 PCT/JP2002/006310 JP0206310W WO03001277A1 WO 2003001277 A1 WO2003001277 A1 WO 2003001277A1 JP 0206310 W JP0206310 W JP 0206310W WO 03001277 A1 WO03001277 A1 WO 03001277A1
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- light
- color
- polarization
- optical system
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
- G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
- G02B27/1026—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with reflective spatial light modulators
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
- G02B27/102—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources
- G02B27/1046—Beam splitting or combining systems for splitting or combining different wavelengths for generating a colour image from monochromatic image signal sources for use with transmissive spatial light modulators
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/1086—Beam splitting or combining systems operating by diffraction only
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/141—Beam splitting or combining systems operating by reflection only using dichroic mirrors
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/145—Beam splitting or combining systems operating by reflection only having sequential partially reflecting surfaces
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/148—Beam splitting or combining systems operating by reflection only including stacked surfaces having at least one double-pass partially reflecting surface
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/10—Beam splitting or combining systems
- G02B27/14—Beam splitting or combining systems operating by reflection only
- G02B27/149—Beam splitting or combining systems operating by reflection only using crossed beamsplitting surfaces, e.g. cross-dichroic cubes or X-cubes
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
- G02B27/285—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining comprising arrays of elements, e.g. microprisms
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3102—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators
- H04N9/3105—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM] using two-dimensional electronic spatial light modulators for displaying all colours simultaneously, e.g. by using two or more electronic spatial light modulators
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/12—Picture reproducers
- H04N9/31—Projection devices for colour picture display, e.g. using electronic spatial light modulators [ESLM]
- H04N9/3141—Constructional details thereof
- H04N9/315—Modulator illumination systems
- H04N9/3167—Modulator illumination systems for polarizing the light beam
Definitions
- the present invention relates to an illumination optical system for equalizing the in-plane illuminance distribution of light emitted from a light source, and a projector having such an optical system.
- the three-panel reflective liquid crystal projector separates the light emitted from the light source into three primary colors of light (red (R), green (G), and blue (B)) by a color separation system. Illuminates three reflective LCD panels for each color light, synthesizes the three primary colors of light modulated by each reflective LCD panel, and enlarges and projects the resulting color image on the screen by the projection lens. Take a picture.
- an optical element having a dichroic surface arranged at 45 ° with respect to the optical axis is often used for color separation and color synthesis, with emphasis on miniaturization of the device.
- a projector has a problem that color unevenness is likely to occur due to the polarization dependence of the spectral characteristic of the dichroic surface, and it is difficult to achieve high image quality.
- Japanese Patent Application Laid-Open Nos. 7-84218 and 11-64794 describe a polarization beam splitter having a wavelength selection retardation plate and a spectral function instead of a dichroic surface.
- An optical system that performs spectroscopy by using a light source has been proposed.
- the present invention efficiently generates illumination light in which the polarization direction of a specific color light is different from that of another color light by about 90 °, and illuminates the illuminated area with uniform illumination distribution with such illumination light. It is an object of the present invention to provide an illumination optical system that can perform the illumination. Further, by applying such an illumination optical system, a polarization-dependent spectral characteristic of a dichroic surface constituting a color separation / synthesis optical system is reduced, and a projector for displaying a high-quality projected image is provided. It is intended to be. Disclosure of the invention
- a first illumination optical system includes a light beam splitting optical element that splits light from a light source into a plurality of partial light beams and condenses each of the partial light beams, and converts each of the partial light beams into a partial light beam of a first color.
- a color light separation optical element that separates the first color partial light beam and the second color partial light beam into different directions or in parallel to each other, and a plurality of polarization separation films.
- a polarizing beam splitter array in which a plurality of reflective films are alternately arranged; and a light beam transmitted through the polarized light separating film or a light beam reflected by the reflective film.
- a polarization direction rotating element wherein the first color partial light beam incident on the polarization separation film is aligned with a first polarization direction, and the second color partial light beam incident on the reflection film is provided.
- a polarization conversion element that emits light with the second polarization direction aligned;
- a transmission optical element that is disposed on the incident side or the emission side of the light conversion element and transmits an image formed by the light beam splitting optical element to the illuminated area; and a illuminated area that transmits a partial light beam emitted from the polarization conversion element.
- a superimposing optical element for superimposing at.
- the light from the light source is first split and condensed into a plurality of partial light beams by the light beam splitting optical element, and each of the plurality of partial light beams is separated by the color light separating optical element into a first color portion.
- the light beam is separated into a light beam and a partial light beam of the second color.
- the separated first color light and second color light enter a polarization conversion element including a polarization beam splitter array and a polarization direction rotation element, and a first color portion having a desired polarization state for each color light.
- the light beam is converted into a light beam and a partial light beam of the second color.
- the polarization beam splitter array has a structure in which a plurality of pairs of a polarization separation film and a reflection film are arranged, and a polarization direction rotating element is provided by a polarization beam splitter corresponding to the position of the polarization separation film or the reflection film. It is selectively located on the exit side of the array.
- the polarization direction rotating element is arranged only on the exit side of the polarization separation film. Therefore, one of the partial light flux of the first color and the partial light flux of the second color is incident on the polarization splitting film, and the other is selectively incident on the reflecting film.
- the partial beams of the first color and the second color are respectively reflected by two types of polarized beams in the polarizing beam splitter array, that is, the partial beam having the first polarization direction transmitted through the polarization separating film and the polarization beam. And a partial light beam having the second polarization direction.
- the polarization direction of one of the two polarized light beams is rotated by about 90 ° by passing through a retardation plate (polarization direction rotating element) such as a 12-wavelength plate. Since the partial light beam of the first color and the partial light beam of the second color are incident on different films (polarization separating film and reflection film), the partial light beam of the first color is directed in the first polarization direction and the partial light beam of the second color is emitted.
- the flux is aligned in the second polarization direction, so that the first color partial light flux and the second color partial light flux are aligned in different polarization directions.
- all partial beams of the first color are aligned with S-polarized light, and all partial beams of the second color are aligned with P-polarized light. These partial light beams are superimposed on the illuminated area via the superimposing optical element.
- the transmission optical element has a function of transmitting each partial light beam to the illuminated area.
- This transmission optical element can be arranged on the incident side or the exit side of the polarization conversion element. If the transmission optical element is arranged on the incident side of the polarization conversion element, each partial light beam can be incident on the polarization conversion element at a predetermined angle, and the polarization separation performance of the polarization separation film can be easily enhanced.
- the transmission optical element is arranged on the emission side of the polarization conversion element, the transmission optical element has the function of a superimposing optical element, so that the superimposing optical element and the transmission optical element are configured as an integrated optical element. It is also possible. Therefore, when it is desired to reduce the number of components, it is more advantageous to dispose the transmission optical element on the exit side of the polarization conversion element.
- the illumination optical system converts the non-polarized light from the light source into a polarized light beam in which the polarization direction is uniform for each color light in advance, so that it is disposed downstream of the illumination optical system on the optical path.
- the dichroic bristles that can be used can reduce the polarization dependence of optical elements such as a polarization beam splitter. Therefore, it is possible to increase the lighting efficiency.
- the second illumination optical system according to the present invention separates light from the light source into first color light and second color light, and separates the first color light and the second color light in different directions or in parallel.
- a color light separating optical element that emits light in a state where the first color light is divided into a plurality of partial light fluxes of a first color, and the second color light is divided into a plurality of partial light fluxes of a second color, and each partial light flux
- a polarization direction rotating element provided at a position where light reflected by the film is emitted, and aligning the partial light flux of the first color incident on the polarization separation film with polarized light having a first polarization direction.
- the second-color portion spectral flux incident on the reflection film is converted into a second polarized light.
- a polarization conversion element that emits the polarized light having the same direction, and a transmission optical element that is disposed on the incident side or the emission side of the polarization conversion element and transmits an image formed by the light beam splitting optical element to the illuminated area.
- a superimposing optical element that superimposes a partial light beam emitted from the polarization conversion element in the illuminated area.
- the light from the light source is first separated into the first color light and the second color light by the color light separation optical element.
- the first color light and the second color light are respectively split and condensed into a plurality of partial light beams by the light beam splitting optical element. That is, the first color light is split into a first color partial light beam, and the second color light is split into a second color partial light beam.
- Each of these partial light beams enters a polarization conversion element having a polarization beam splitter array and a polarization direction rotating element, and is converted into a first color partial light beam and a second color partial light beam having a desired polarization state for each color light. Is converted.
- the configuration of the polarization beam splitter array is the same as that of the above-described first illumination optical system. Therefore, one of the first color partial light beam and the second color partial light beam is incident on the polarization separation film, and the other is incident on the reflection film. The subsequent operation is the same as that of the first illumination optical system.
- the same effect as in the first illumination optical system can be obtained because the non-polarized light from the light source is converted into a polarized light beam having the same polarization direction for each color light in advance. And it is possible.
- the color light separating optical element is disposed between the light source and the light beam splitting element, so that highly parallel light can be made incident on the color light separating optical element. Therefore, in the color light separation optical element, the separation of the color light can be reliably performed with higher efficiency.
- the transmission optical element can be arranged on the incident side or the exit side of the polarization conversion element.
- a third illumination optical system includes a light beam splitting optical element that splits light from a light source into a plurality of partial light beams and condenses each of the partial light beams, and converts each of the partial light beams into a first color portion.
- a color light separation optical element that separates the light beam and the second color partial light beam and emits the first color partial light beam and the second color partial light beam in different directions or in parallel, respectively, and a plurality of polarization separations
- the partial light flux of the first color which is incident on the incident side end face on which the polarization direction rotating element is not provided on the emission side and passes through the polarization separation film, and the adjacent polarized light after being reflected by the polarization separation film Reflected again by separation membrane
- the first color partial light beam transmitted through the polarization direction rotating element is aligned with the first polarization direction, and the polarization direction rotating element is provided on the incident side end face on the emission side of the polarization separation film.
- a polarization conversion element that aligns and emits the second color partial light beam in the second polarization direction, and receives an image formed by the light beam splitting optical element, which is disposed on the incident side or the emission side of the polarization conversion element.
- a transmission optical element for transmitting to the illumination area;
- Superposition optics for superimposing a partial light beam emitted from the polarization conversion element in an illuminated area And an element.
- the light from the light source is first split and condensed into a plurality of partial light beams by the light beam splitting optical element, and each of the plurality of partial light beams is separated by the color light separating optical element into a first color portion.
- the light beam is separated into a light beam and a partial light beam of the second color.
- the separated first color light and second color light are incident on a polarization conversion element including a polarization beam splitter array and a polarization direction rotating element, and are combined with a first color partial light beam having a desired polarization state for each color light. It is converted to a second color partial light flux.
- the polarization beam splitter array has a structure in which a plurality of polarization separation films are arranged, and the polarization direction rotating element selects a position on the exit side of the polarization beam splitter array corresponding to the position of a specific polarization separation film.
- a polarization direction rotating element is arranged only on the emission side of every other polarization separation film.
- the polarization separation film having the polarization direction rotation element on the emission side is referred to as polarization separation film A
- the polarization separation film without the polarization direction rotation element on the emission side is referred to as polarization separation film B for convenience.
- one of the first color partial light beam and the second color partial light beam enters the polarization separation film B, and the other selectively enters the polarization separation film A.
- the polarization separation films A and B separate the incident partial light beam into a partial light beam having a first polarization direction and a reflected partial light beam having a second polarization direction, similarly to the above-described polarization separation films. .
- the partial light beam transmitted through the polarization separation film B is emitted from the polarization conversion element as a partial light beam having the first polarization direction.
- the partial light beam reflected by the polarization separation film B is a partial light beam having the second polarization direction, but after being reflected again by the adjacent polarization separation film A, a partial retarder such as a two-wavelength plate
- the polarization direction is rotated by about 90 °, and is emitted from the polarization conversion element as a partial light beam having the first polarization direction.
- the partial luminous flux transmitted through the polarization separation film A is a partial luminous flux having the first polarization direction, but passes through a retardation plate such as a ⁇ / 2 wavelength plate to change the polarization direction by about 9%.
- the light is rotated by 0 ° and is emitted from the polarization conversion element as a partial light beam having the second polarization direction. Further, the partial light beam reflected by the polarization separation film B is reflected again by the adjacent polarization separation film B, and then emitted from the polarization conversion element as a partial light beam having the second polarization direction. Since the partial light flux of the first color and the partial light flux of the second color are incident on the polarization separation film that is distinguished by the presence or absence of the polarization direction rotating element, the partial light flux of the first color is emitted in the first polarization direction and the light flux of the second color is emitted. The partial light beams are aligned in the second polarization direction, so that the partial light beams of the first color and the partial light beams of the second color are aligned in different polarization directions.
- all partial beams of the first color are aligned with P-polarized light, and all partial beams of the second color are aligned with S-polarized light. These partial light beams are superimposed on the illuminated area via the superimposing optical element.
- the subsequent operation is the same as that of the first illumination optical system.
- the third illumination optical system has the shortest optical path length of the partial luminous fluxes of the first color and the second color in the polarization conversion element as compared with the first and second illumination optical systems. The optical path length difference between the partial light beam to be generated and the partial light beam having the longest optical path length can be reduced.
- the magnification of the partial luminous flux of the first color can be easily matched with the magnification of the partial luminous flux of the second color.
- lighting efficiency can be improved.
- the polarization beam splitter arrays in the first and second illumination optical systems described above include a polarization separation film and a reflection film, whereas the polarization beam splitter array in the third illumination optical system includes a polarization beam splitter. Since it is configured with only the film, the structure of the polarizing beam splitter array is simple and easy to manufacture.
- the fourth illumination optical system separates the light from the light source into a first color light and a second color light, and separates the first color light and the second color light into different directions or parallel directions, respectively.
- a color light separating optical element that emits light in a state where the first color light is divided into a plurality of partial light fluxes of a first color, and the second color light is divided into a plurality of partial light fluxes of a second color, and each partial light flux
- a polarizing beam splitter array in which a plurality of polarization separating films are arranged at a predetermined interval; and a polarization beam splitter array arranged at the predetermined interval and provided on an emission side of the polarizing beam splitter array.
- the light from the light source is first separated into the first color light and the second color light by the color light separation optical element.
- the first color light and the second color light are respectively split and condensed into a plurality of partial light beams by the light beam splitting optical element. That is, the first color light is split into a first color partial light beam, and the second color light is split into a second color partial light beam.
- Each of these partial light beams enters a polarization conversion element having a polarization beam splitter array and a polarization direction rotating element, and is converted into a first color partial light beam and a second color partial light beam having a desired polarization state for each color light. Is converted.
- the configuration of the polarizing beam splitter array is the same as that of the above-described third illumination optical system. Therefore, the first color partial light beam enters the polarization separation film B, and the second color partial light beam enters the polarization separation film A in a position-selective manner.
- the subsequent operation is the same as the above-described third illumination optical system.
- the fourth illumination optical system as in the above-described third illumination optical system, the first and second colors in the polarization conversion element are different from those in the first and second illumination optical systems.
- the optical path length difference between the partial light beam having the shortest optical path length and the partial light beam having the longest optical path length can be reduced.
- the magnification of the partial luminous flux of the first color can be easily matched with the magnification of the partial luminous flux of the second color.
- lighting efficiency can be improved.
- the structure of the polarization beam splitter array is simple and easy to manufacture.
- the color light separating optical element used in the first, second, third, and fourth illumination optical systems includes two mirrors, one optical component having two mirrors, a reflection hologram, or It can be constituted by a transmission hologram.
- the first mirror may be a dichroic mirror for performing color separation
- the second mirror may be a reflecting mirror.
- Dichroic mirrors and reflection mirrors generally have high reflectance. Therefore, if a configuration using such a mirror is used, it is possible to reliably separate color light with high efficiency.
- the reflection mirror can be configured not only by a general reflection mirror formed of a metal film such as aluminum but also by a dichroic mirror that reflects light of a specific color. According to such a configuration, unnecessary light (for example, specific color light such as infrared light, ultraviolet light, yellow light, etc.) can be eliminated from the illumination light by the color light separation optical element.
- the reliability of the light modulator used in the projector can be improved, and the quality of the projected image can be improved.
- the function of the second mirror is to reflect a specific color light transmitted through the first mirror, it is not always necessary to use the second mirror as a dichroic mirror.
- a dichroic mirror it is easier to obtain a higher reflectance than a general reflection mirror, so that it is convenient to increase the light use efficiency in the color light separation optical element.
- the first mirror and the second mirror are preferably arranged as follows.
- the first mirror and the second mirror are non-parallel to each other, and the first mirror is arranged at an angle of 45 ° with respect to an optical axis of the light source;
- the mirror is arranged at an angle of (45- ⁇ ) ° with respect to the optical axis of the light source.
- the first mirror and the second mirror are not parallel to each other, and the first mirror is disposed at an angle of (45 + c) ° with respect to an optical axis of the light source;
- the second mirror is arranged at an angle of 45 ° to the optical axis of the light source.
- the first mirror is disposed at an angle of (45 + 3) ° with respect to the optical axis of the light source
- the second mirror is disposed at an angle of (45 ⁇ 3) ° with respect to the optical axis of the light source. It is arranged in. (4)
- the first mirror and the second mirror are arranged parallel to each other at a predetermined interval and at an angle of 45 ° to the optical axis of the light source.
- the arrangement of (3) or (4) is preferable in that the color light can be symmetrically separated with respect to a predetermined axis, and the configuration of the transmission optical element is simplified.
- the function of the color light separating optical element is to change the direction of the light beam emitted toward the polarization conversion element between the first color partial light beam and the second color partial light beam.
- the first mirror and the second mirror may be arranged in a non-parallel state to each other, so that the first mirror and the second mirror are different. Is not limited to the above example. However, it is necessary to appropriately set the optical characteristics of the transmission optical element according to the angle of incidence of the color light on the transmission optical element.
- the color light separating optical element is configured by one optical component having two mirrors.
- One optical component having two mirrors is as follows.
- An optical component comprising: a dichroic mirror provided between the transparent member and the right-angle prism.
- An optical component comprising: a dichroic mirror provided between the translucent member and the right-angle prism.
- the color light separating optical element is one such optical component, the assembly of the optical system can be facilitated.
- optical components such as (B) and (C) are used, light is transmitted to the dichroic mirror via a right-angle prism having a refractive index larger than 1. Since the incident, narrowed the incident angle of the dichroic mirror one ⁇ ⁇ light, with enhanced spectral properties of Daikuroi Kkumira, further c can be eliminated optical path shift, the use of the optical component such as a (C) Since the size of the prism portion is reduced, the color light separating optical element can be reduced in size and weight.
- the reflecting mirror can be configured not only by a general reflecting mirror formed of a metal film such as aluminum but also by a dichroic mirror that reflects a specific color light. it can. Since the function of the second mirror is to reflect a specific color light transmitted through the first mirror, it is not always necessary to use the second mirror as a dich-mouth mirror. On the other hand, when a dichroic mirror is used, a higher reflectance can be easily obtained as compared with a general reflecting mirror, so that it is convenient to increase the light use efficiency in the color light separating optical element.
- one surface on which the dichroic mirror force S is provided and the other surface on which the reflection mirror is provided are arranged as follows.
- the first surface and the second surface are not parallel to each other, and the first surface is arranged at an angle of 45 ° with respect to an optical axis of the light source;
- the surface is arranged at an angle of (45- ⁇ ) ° with respect to the optical axis of the light source.
- the first surface and the second surface are not parallel to each other, and the first surface is disposed at an angle of (45 + ⁇ ) ° with respect to an optical axis of the light source;
- the second surface is arranged at an angle of 45 ° with respect to the optical axis of the light source.
- the first surface and the second surface are not parallel to each other, and the first surface is disposed at an angle of (45+) ° with respect to an optical axis of the light source;
- the surface 2 is disposed at an angle of (45- °) with respect to the optical axis of the light source.
- the first surface and the second surface are arranged parallel to each other at a predetermined interval and at an angle of 45 ° to the optical axis of the light source.
- the arrangement as shown in (c) or (d) is preferable in that the color light can be separated symmetrically with respect to a predetermined axis, and the configuration of the transmission optical element is simplified.
- the function of the color light separating optical element is to change the direction of the light beam emitted toward the polarization conversion element between the first color partial light beam and the second color partial light beam.
- the first surface and the second surface only need to be arranged in a non-parallel state to each other, so that the first surface and the second surface are different from each other.
- the arrangement angle is not limited to the above example. However, it is necessary to appropriately set the optical characteristics of the transmission optical element in accordance with the angle of incidence of the color light on the transmission optical element.
- the color light separating optical element is constituted by a reflection hologram element or a transmission hologram element.
- the color light separation optical element can be constituted by one plate-like hologram, the number of components of the color light separation optical element can be reduced, and the size and weight of the illumination optical system can be reduced. It is possible to plan.
- the light beam splitting optical element used in the illumination optical system according to the present invention can be constituted by a lens array, a mirror array, a light guide rod having a plurality of reflecting surfaces, and the like.
- a mirror array is less expensive than using a lens array or light guide.
- the spherical aberration inherent to the lens array does not occur, so that the light collecting property can be improved and the illumination efficiency can be improved.
- a dichroic filter array for blocking incidence of unnecessary color light be provided on the incident side of the polarizing beam splitter array. If a dichroic filter array is provided in this way, unnecessary color light will be incident on the polarizing beam splitter array, even when a color light separation optical element whose incident angle dependence 'I' in spectral characteristics is relatively large is used.
- the dichroic filter array includes the transmission optical element. It can be arranged not only between the light and the polarization conversion element but also on the incident side of the transmission optical element.
- the color light separating optical element may include a green light. It is preferable to have a color separation characteristic of separating light from red and blue light. This makes it easier to optimize the selection characteristics of green light in the color light separating optical element. Therefore, if the illumination optical system having such a configuration is employed in the projector, the contrast and the utilization efficiency of green light can be further enhanced, and a bright projected image can be displayed with a higher contrast.
- a light modulation device for modulating light emitted from the illumination optical system, and a projection lens for projecting the light modulated by the light modulation device.
- the illumination optical system according to the present invention is preferably employed in the following projector.
- the light emitted from the second reflection-type light modulator and the light emitted from the third reflection-type light modulator are combined to form the polarization light.
- a color light separation / combination element that emits light toward the beam splitter, and emits light from the first reflection type light modulator.
- an illumination optical system as described above, a first reflection type light modulation device that modulates the first color light included in the light emitted from the illumination optical system, and an illumination optical system emitted from the illumination optical system.
- a second reflection type light modulation for modulating a third color light included in the second color light.
- An apparatus a third reflective light modulator that modulates a fourth color light included in the second color light emitted from the illumination optical system, and first to fourth polarization beam splitters;
- a first wavelength-selective phase difference plate provided between a first polarization beam splitter and the third polarization beam splitter; and a first wavelength-selection phase difference plate provided between the third polarization beam splitter and the fourth polarization beam splitter.
- a projection lens that projects light emitted from the fourth polarization beam splitter, wherein the first polarization beam splitter is emitted from the illumination optical system.
- the first color light and the second color light, and the second polarization beam splitter converts the first color light separated by the first polarization beam splitter into the first color light and the second color light.
- Lead to the reflective light modulator of 1 the first color light modulated by the first reflection type light modulation device is guided to the fourth polarization beam splitter, and the first wavelength selection phase difference plate includes the first polarization beam.
- the third color light and the fourth color light included in the light of the second color separated by the splitter only the polarization direction of the third color light is rotated by about 90 °.
- the polarizing beam splitter transmits the third color light and the fourth color light emitted from the first wavelength selection phase difference plate to the second reflection type light modulation device and the third reflection type light modulation device. And the third color light and the fourth color light modulated by the second reflection type light modulation device and the third reflection type light modulation device.
- the second wavelength-selective phase difference plate, the third polarization beam splitter Of the third color light and the fourth color light emitted from the light source only the polarization direction of the third color light is rotated by about 90 °, and the fourth polarization beam splitter And the third color light and the fourth color light emitted from the second wavelength-selective phase difference plate, which are emitted from the polarization beam splitter, and are combined toward the projection lens. Projector to eject.
- a color separation optical system that separates one color light, a second color light, and a third color light, and modulates the first color light separated by the color separation optical system according to an image signal.
- First transmission type A light modulation device a second transmission type light modulation device that modulates the light of the second color separated by the color separation optical system according to an image signal
- the third light separation device separated by the color separation optical system.
- a third transmission light modulator that modulates color light in accordance with an image signal, the first transmission light modulator, the second transmission light modulator, and the third transmission light modulation
- a color combining optical system that combines the light of the first color, the light of the second color, and the light of the third color, each of which is modulated by a device; and a projection that projects the light combined by the color combining optical system.
- a projector comprising: a lens;
- the polarization dependence of spectral characteristics in dichroic mirrors, dichroic prisms, polarizing beam splitters, etc. is reduced, and higher image quality of the projected image can be achieved.
- Higher brightness and lower cost of the optical system that separates and combines color light can be realized at the same time.
- all the color lights pass through the two polarizing beam splitters and reach the projection lens, so that the contrast of the projected image of the projector can be further increased.
- the first and fourth polarizing beam splitters can be replaced with dichroic mirrors or dichroic prisms, in which case cost reduction can be achieved.
- the above-described illumination optical system according to the present invention is configured such that, among the three color lights of the first color light, the second color light, and the third color light, the polarization state of one color light is made different from the polarization state of the other two color lights. Can be injected. For this reason, usually, three transmission light modulators that respectively modulate the first color light, the second color light, and the third color light, and the first color light modulated by these transmission type light modulation devices. In a so-called three-plate type projector including a color combining optical system that combines light of the second color and light of the third color, a transmission type optical system is used to improve the efficiency of combining color light in the color combining optical system.
- a half-wave plate is arranged to make the polarization state of at least one color light incident on the color combining optical system different from the polarization state of the other color lights.
- the illumination optical system of the present invention is used for such a purpose. As a result, cost reduction can be achieved.
- the illumination optics uses green light as S-polarized light and blue and red light as P-polarized light.
- the ⁇ / 2 wavelength plate immediately before or immediately after the transmission type optical modulator is unnecessary.
- each transmission is performed immediately before or immediately after all of the first to third transmission light modulators. Since the same number of two-wavelength plates are required for each type of light modulator, the same number of two-wavelength plates are arranged in the optical path for each color, and the same number of L-wavelength two-wavelength plates, color unevenness can be reduced.
- the polarization state of light incident on the transmission type light modulation device may be limited. For example, when green light is incident on the transmission light modulator as S-polarized light and blue and red light as P-polarized light, the configuration of the projector described in (III) is effective. BRIEF DESCRIPTION OF THE FIGURES
- FIG. 1 is a schematic configuration diagram showing Embodiment 1 of a projector including an illumination optical system according to the present invention
- FIG. 2 is a detailed configuration of a polarization conversion element used in the illumination optical system according to the present invention.
- FIG. 3 is a schematic configuration diagram showing a second embodiment of a projector including the illumination optical system according to the present invention.
- FIG. 4 is a schematic diagram illustrating an embodiment of the projector including the illumination optical system according to the present invention.
- FIG. 5 is a schematic configuration diagram showing Embodiment 3;
- FIG. 5 is a schematic configuration diagram showing Embodiment 4 of a projector including the illumination optical system according to the present invention;
- FIG. 6 is a diagram showing an illumination optical system according to the present invention.
- FIG. 1 is a schematic configuration diagram showing Embodiment 1 of a projector including an illumination optical system according to the present invention
- FIG. 2 is a detailed configuration of a polarization conversion element used in the illumination optical system according to the present invention.
- FIG. 7 is a schematic configuration diagram showing a fifth embodiment of a projector including the same
- FIG. 7 is a schematic configuration diagram showing a sixth embodiment of the illumination optical system according to the present invention
- FIG. 8 is a modification of the polarization conversion element.
- Cross section showing configuration 9 (a) and 9 (b) are views showing another embodiment of the color light separating optical element used in the illumination optical system according to the present invention
- FIG. 11 (b) is a diagram showing another embodiment of the color light separating optical element used in the illumination optical system according to the present invention.
- FIGS. 11 (a) and 11 (b) show the illumination optical system according to the present invention.
- FIG. 12 is a view showing another embodiment of the color light separating optical element used in the present invention.
- FIG. 12 is a view showing another embodiment of the color light separating optical element used in the illumination optical system according to the present invention.
- FIG. 13 is a diagram showing another embodiment of the color light separating optical element used in the illumination optical system according to the present invention
- FIG. 14 is a diagram showing the illumination optical device according to the present invention.
- FIG. 15 is a view showing another embodiment of the color light separating optical element used in the system.
- FIG. 15 is a view showing another example of the light beam splitting optical element and the color light separating optical element used in the illumination optical system according to the present invention.
- FIG. 16 is a diagram showing an embodiment, FIG. 16 is an explanatory diagram showing reflection characteristics of a dichroic mirror used in the illumination optical system according to the present invention, and FIG.
- FIG. 17 is an illumination optical system according to the present invention.
- FIG. 18 is an explanatory diagram showing spectral characteristics of a dichroic prism used in the present invention.
- FIG. 18 is an explanatory diagram showing optical characteristics of a wavelength-selective phase difference plate used in a projector using an illumination optical system according to the present invention.
- FIG. 1 shows an embodiment of a projector including an illumination optical system according to the present invention.
- This projector is composed of a Teruo optical system 10, a color separation / synthesis optical system 100, three reflective liquid crystal panels 200R, 200G, and 20OB as light modulators. And a projection lens 210.
- the illumination optical system 10 includes a light source 20 that emits a substantially parallel light beam, a first lens array 30 that forms a light beam splitting optical element, a color light separation optical element 40, and a polarization conversion element 50. It has a second lens array 60 as an optical element and a superimposing lens 70 as a superimposing optical element, and has a function of generating an illumination luminous flux whose polarization direction is almost the same for each color light. .
- the light source 20 has a light source lamp 21 and a concave mirror 22.
- the light radiated from the light source lamp 21 is reflected in one direction by the concave mirror 22 and is incident on the first lens array 30 as a substantially parallel light beam.
- the light source lamp 21 a metal halide lamp, a xenon lamp, a high-pressure mercury lamp, a halogen lamp, etc.
- the concave mirror 22 a parabolic reflector, an elliptical reflector, a spherical reflector, or the like can be used.
- the first lens array 30 has a configuration in which a plurality of small lenses 31 having a contour shape substantially similar to the illuminated area are arranged in a matrix of M rows and N columns.
- the illuminated area is the display area of the reflective liquid crystal panel, and its outline is rectangular, so that the small lens 31 is also set to have a rectangular outline.
- Each of the small lenses 31 divides the substantially parallel light beam incident from the light source 20 into a plurality (MX N) of partial light beams, and individually condenses each of the partial light beams near the polarization conversion element 50.
- the polarization conversion element 50 is disposed at a position where the partial light beam of the first lens 30 is converged.
- the color light separating optical element 40 is disposed between the first lens array 30 and the second lens array 60, and includes a dichroic mirror 41 as a first mirror and a first mirror 41. And a reflecting mirror 42 as a second mirror disposed on the rear side.
- the dichroic mirror 41 has a spectral characteristic as shown in FIG. 16, reflects red light (R) and blue light (B), and transmits green light (G).
- the reflection mirror 42 is composed of a general reflection mirror formed of a metal film such as aluminum, or a dichroic mirror that reflects green light (G).
- the dichroic mirror 42 Since the function of the reflecting mirror 42 is to reflect a specific color light transmitted through the dichroic mirror 41, it is not necessary to use a dichroic mirror, but it is necessary to use a dichroic mirror as compared with a general reflecting mirror. Since a high reflectivity is easily obtained with an external mirror, it is convenient to enhance the light use efficiency of the color light separating optical element 40.
- the dichroic mirror can be formed by a dielectric multilayer film.
- the dichroic mirror 41 converts all of the partial light beams emitted from the first lens array 30 into a first color partial light beam, which is green light (G), and red light (R) and blue light. (B) and a partial light flux of the second color which is a composite color with (B).
- the dichroic mirror 41 and the reflecting mirror 42 are not parallel to each other,
- the ichroic mirror 41 is disposed at an angle of 45 ° with respect to the optical axis La of the light source 20.
- the reflecting mirror 42 is positioned at (45 ⁇ H) ° with respect to the optical axis La of the light source 20. They are arranged at an angle (however, ⁇ > 0).
- the dichroic mirror 41 is disposed at an angle of (45 + c.) With respect to the optical axis La of the light source 20, and the reflecting mirror 42 is placed at 45 ° with respect to the optical axis La of the light source 20. May be arranged at an angle.
- the color light separating optical element 40 converts the first color partial luminous flux (G) and the second color partial luminous flux (B + R) into the second Are emitted in different directions toward the lens array 60.
- the function of the color light separating optical element 40 is to make the direction of the light beam emitted toward the second lens array 60 different between the first color partial light beam and the second color partial light beam. Therefore, in order to realize this function, the dichroic mirror 41 and the reflection mirror 42 may be arranged in a non-parallel state to each other. Therefore, the dichroic mirror 41 and the reflection mirror 42 can be arranged at angles other than those described above.
- the shapes and optical characteristics of the lenses 61 and 62 constituting the second lens array 60 must be set in accordance with the incident angle of the color light to the second lens array 60. Is required.
- the second lens array 60 includes a concentric lens 61 corresponding to each of the partial beams (B + R) of the second color, and an eccentric lens 62 corresponding to each of the partial beams (G) of the first color. Are arranged in a matrix of M rows and N columns.
- the second lens array 60 causes the concentric lens 61 to cause each of the second color partial luminous fluxes (B + R) to enter a polarization separation film 54 of the polarization conversion element 50, which will be described later.
- Each of the partial beams (G) of the first color is made incident on a reflection film 55 of the polarization conversion element 50 described later by 62.
- the concentric lens 61 is a lens having an optical axis at the physical center of the lens body
- the eccentric lens 62 is a lens having an optical axis at a distance from the physical center of the lens body.
- each partial light beam (B + R) of the second color enters the polarization conversion element 50 almost perpendicularly. Therefore, lenses for these partial light beams are concentric lenses 61.
- each partial light beam (G) of the first color is slightly inclined with respect to the polarization conversion element 50. Incident on. Therefore, lenses for these partial light beams are decentered lenses 62. That is, the eccentric lens 62 bends the optical axis of the partial light beam, and the light beam enters the polarization conversion element 50 almost perpendicularly.
- the dichroic mirror 41 is set to (45 + ⁇ ) with respect to the optical axis La of the light source 20.
- the reflection mirror 42 is arranged at an angle of 45 ° with respect to the optical axis La of the light source 20
- the position of the concentric lens 61 and the position of the eccentric lens 62 are set.
- the direction of the eccentric lens 62 may be set opposite to that in FIG. 1 (the thin part of the lens is closer to the light source 20).
- the second lens array 60 can be arranged on the exit side of the polarization conversion element 50.
- the second lens array 60 has only a function of transmitting the incident partial light beam to the liquid crystal panel, which is the area to be illuminated.
- the second lens array 60 can also have a function of a superimposing lens 70 described later.
- the polarization conversion element 50 is composed of a polarization beam splitter array 51 and a Z-wavelength plate 52 as a polarization direction rotating element arranged on the exit side of the polarization beam splitter array 51.
- the polarization beam splitter array 51 has a configuration in which a plurality of columnar translucent members 53 having a parallelogram cross section are bonded together.
- the translucent member 53 optical glass is generally used, but other materials (for example, plastic or crystal) may be used.
- the polarization separation films 54 and the reflection films 55 are alternately arranged.
- the polarization separation film 54 and the reflection film 55 are inclined by about 45 ° with respect to the incident end face 51a of the polarization conversion element 50. Further, the polarization separation film 54 and the reflection film 55 form a pair, and the number of the pair corresponds to the number N of columns or the number M of rows of the first lens array 30.
- the polarization separation film 54 is composed of a dielectric multilayer film or the like, and separates unpolarized light into two types of linearly polarized light whose polarization directions are orthogonal to each other. For example, it has a polarization separation characteristic of transmitting P-polarized light and reflecting S-polarized light.
- the reflection film 55 is composed of a dielectric multilayer film, a metal film, or the like.
- the two-wavelength plate 52 is provided at a position where the light transmitted through the polarization separation film 54 is emitted, and rotates the polarization direction of the transmitted polarized light by 90 °. This means that P-polarized light is converted to S-polarized light and S-polarized light is converted to P-polarized light.
- the polarization conversion element 50 is composed of a polarization beam splitter array 51 and a Z2 wavelength plate 52 in combination with a partial beam (B + R) of the second color incident on the polarization separation film 54. ) Is converted into S-polarized light as polarized light having the second polarization direction, and all the partial luminous fluxes (G) of the first color incident on the reflection film 55 have the first polarization direction. Convert to P-polarized light as polarized light. The conversion process will be described later.
- ⁇ the two-wavelength plate 52 is provided at a position where the light reflected by the reflection film 55 is emitted, the first color partial light beam (G) is converted into S-polarized light, and the second color partial light beam (B + A configuration that converts R) into P-polarized light can also be adopted.
- the superimposing lens 70 is disposed on the exit side of the polarization conversion element 50, and serves to illuminate all of the partial luminous flux emitted from the polarization conversion element 50, i.e., three reflective liquid crystal panels 200R. , 200 G, and 20 OB.
- a parallel lens 99 is arranged to convert the central optical path of each partial light flux reaching the illuminated area so that it is substantially parallel to the illumination optical axis L. The illumination efficiency in the illuminated area is improved.
- the color separation / synthesis optical system 100 will be described.
- the color separation / combination optical system 100 has a polarization beam splitter 110 and a dichroic prism 120 serving as a color light separation / combination element.
- the polarizing beam splitter 111 is an optical element in which a polarized light separating film 113 is formed on the joining surface of two rectangular prisms 111, 112, and one incident end face 111. 4, one exit end face 115, and two incident end faces 116, 117.
- the polarized light separating film 113 is composed of a dielectric multilayer film or the like, and has, for example, a polarized light separating characteristic of transmitting P-polarized light and reflecting S-polarized light.
- the entrance end face 114 of the polarizing beam splitter 110 faces the collimating lens 99 and serves as an entrance face of light from the illumination optical system 110.
- a projection lens 210 is arranged to face the emission end face 115 of the polarizing beam splitter 110, and a reflective liquid crystal panel 200G is arranged to face the incidence end face 116.
- the dichroic prism 120 is an optical element in which a dichroic surface 123 is formed on a joining surface of two right-angle prisms 122 and 122, and three incident and exit end surfaces 124. , 125, 126.
- the dichroic surface 123 is formed of a dielectric multilayer film or the like and has at least a color separation characteristic of reflecting red light.
- the dichroic prism 1 20 has an incident 'outgoing end face 1 2 4 joined to the incoming and outgoing end face 1 1 7 of the polarizing beam splitter 1 1 0, and has a reflective liquid crystal panel 2 0 0 on the incoming and outgoing end face 1 2 5 B is disposed on the other entrance / exit end face 126 with the reflection type liquid crystal panel 20 OR force facing each other.
- the light from the light source 20 is split into a plurality of partial beams by the small lenses 31 of the first lens array 30 and is incident on the color light separating optical element 40.
- Each partial light beam is converted by the dichroic mirror 41 of the color light separating optical element 40 into a partial light beam of the first color, which is green light (G), and a composite color of red light (R) and blue light (B).
- Each of the partial beams of the second color is reflected by the dichroic mirror 41, passes through the concentric lens 61 of the second lens array 60, and is split into the partial beam of the second color 51.
- side Light is incident on the light separation film 54.
- each partial light beam of the first color passes through the dichroic mirror 41, is reflected by the reflecting mirror 42, passes through the eccentric lens 62 of the second lens array 60, and is reflected by the reflecting film of the polarizing beam splitter array 51. It is incident on 5 5.
- the second color partial light beam (B + R) incident on the polarization splitting film 54 of the polarization beam splitter array 51 is separated into P-polarized light transmitted through the polarization splitting film 54 and S-polarized light reflected. It is.
- the P-polarized light transmitted through the polarization separation film 54 is rotated by 90 ° by passing through the ⁇ two-wavelength plate 52, and is converted into S-polarized light.
- the S-polarized light reflected by the polarization separation film 54 is reflected again by the adjacent reflection film 55, and travels in almost the same direction as the polarized light transmitted through the polarization separation film 54. Since the light does not pass through the 12-wavelength plate 52, the polarization direction does not change and remains S-polarized light. Therefore, the second-color partial light beam (B + R) that has entered the polarization separation film 54 is aligned with the S-polarized light and emitted from the polarization conversion element 50.
- the first color partial light beam (G) incident on the reflection film 55 of the polarization beam splitter array 51 passes through the reflection film 55 and enters the polarization separation film 54, so that the first color partial light beam (G)
- the direction in which G) is incident on the polarization splitting film 54 differs by 90 ° with respect to the partial light beam ( ⁇ + R) of the second color. Therefore, the S-polarized light reflected by the polarization separation film 54 through the reflection film 55 rotates the polarization direction by 90 ° by passing through the half-wave plate 52, and is converted into ⁇ -polarized light. .
- the polarized light transmitted through the polarization separation film 54 through the reflection film 55 is reflected by another adjacent reflection film 55, and is substantially in the same direction as the polarization light reflected by the polarization separation film 54.
- this polarized light does not pass through the half-wave plate 52, the polarization direction does not change and remains as ⁇ -polarized light. Therefore, the partial light beam (G) of the first color that has entered the reflective film 55 is aligned with the ⁇ -polarized light and emitted from the polarization conversion element 50.
- light rays represented by solid lines represent ⁇ -polarized light
- light rays represented by broken lines represent S-polarized light.
- the same rule applies to the light ray display in the color separation / synthesis optical system 100 shown in FIG.
- the luminous flux (B + R) is superimposed by the superimposing lens 70 on three reflective liquid crystal panels 200R, 200G, and 20OB, which are illuminated areas.
- the partial light beam (G) of the first color is all P-polarized light. Then, the light passes through the polarized light separating film 113 of the polarizing beam splitter 110, goes straight, and enters the reflective liquid crystal panel 200 G from the input / output end face 116.
- the partial light beam (G) of the first color is modulated by the reflective liquid crystal panel 200G in accordance with external image information (not shown), and the light beam partially containing S-polarized light depending on the degree of modulation.
- the light is reflected by the reflection type liquid crystal panel 200G, returns to the incident end face 116, and enters the polarized light separating film 113 of the polarizing beam splitter 110.
- the modulated flux converted to S-polarized light is reflected by the polarized light separation film 113, passes through the exit end face 115, and is projected into the projection lens 210.
- the reflective liquid crystal panels 200R, 200G, and 200B are well known, a detailed description of their structures and operations is omitted.
- the partial beams (B + R) of the second color are all S Since the light is polarized light, it is reflected by the polarized light separating film 113 of the polarizing beam splitter 110 and enters the dichroic surface 123 of the dichroic prism 120. Red light Out of the partial light flux (B + R) of the second color that has entered the dichroic surface 1 23 of the dichroic prism 120, the red light is reflected by the dichroic surface 1 23 and the incident / exit end surface 1 From 26, the light enters the reflective liquid crystal panel 200R.
- the red light is modulated by the reflective liquid crystal panel 200 OR, partially converted into a light beam containing P-polarized light depending on the degree of modulation, and reflected by the reflective liquid crystal panel 200 R to be incident.
- the light is reflected by the dichroic face 123 and enters the polarized light splitting film 113 of the polarizing beam splitter 110.
- the luminous flux modulated and converted into the P-polarized light passes through the polarized light separating film 113, passes through the exit end face 115, and enters the projection lens 210.
- the blue light passes through the dichroic surface 123 and enters and exits The light enters the reflective liquid crystal panel 200B through 125.
- the blue light is modulated by the reflection type liquid crystal panel 20 OB, reflected, returned to the incidence end face 125, transmitted through the dichroic face 123, and polarized beam splitter 111.
- the light is incident on the polarized light separating film 1 1 3.
- the modulated! 3 polarized light is transmitted through the polarized light separating film 113, passes through the exit end face 115, and enters the projection lens 210.
- the dichroic prism 120 a prism having a large polarization dependence in spectral characteristics as exemplified in FIG. 17 can be used. Since the red light (R) and the blue light (B) are separated by the dichroic prism 120, the wavelength region corresponding to the wavelength of the green light (G) that is not incident has a large polarization dependence. Wavelength region. Therefore, in the dichroic prism 120, red light (R) and blue light (B) can be efficiently separated and synthesized, and high image quality and high luminance can be realized. Of course, depending on the configuration of the dichroic surface, it is also possible to realize a dichroic prism having a small polarization-dependent spectral characteristic. Because of the increase, it is difficult to reduce costs.
- the polarization dependence of the spectral characteristics of the dichroic prism 120 can be reduced, and the projector using the dichroic prism 120 in the color separation / combination optical system can improve the quality of the projected image. It is also possible to simultaneously reduce the cost of color separation and combining optics.
- the partial light beam (G) of the first color passes only through the polarizing beam splitter 110, the light use efficiency of green light, which has a significant effect on brightness, is high, and high brightness can be easily achieved. it can.
- the non-polarized light beam from the light source 20 is converted into a polarized light beam having the same polarization direction for each color light before entering the color separation / combination optical system 100. As a result, lighting efficiency can be improved. (Embodiment 2)
- FIG. 3 shows another embodiment of the projector including the illumination optical system according to the present invention.
- This embodiment is different from the first embodiment described above in that the mirrors 41 and 42 of the color light separating optical element 40 and the dichroic filter array 56 are provided. different.
- Other configurations are the same as those in the first embodiment.
- the same components as those already described are denoted by the same reference numerals as in FIGS. 1 and 2. And the description is omitted.
- a light ray indicated by a solid line indicates P-polarized light
- a light ray indicated by a broken line indicates S-polarized light.
- the dichroic mirror 41 and the reflecting mirror 42 of the color light separating optical element 40 are not parallel to each other, and the dichroic mirror 41 is positioned at (45+ ] 3)
- the reflection mirror 42 is disposed at an angle of (45_ / 3) ° with respect to the optical axis La of the light source 20 (where j3> 0).
- the entrance aperture 54A corresponding to the polarization separation film 54 of the polarization beam splitter array 51 transmits only the second color partial light beam (B + R) and transmits the first color partial light beam (G).
- Shielding filter 580 Power
- the entrance aperture 55A corresponding to the reflection film 55 transmits only the partial beam (G) of the first color and transmits the partial beam (B + R) of the second color.
- the shielding filters 57 are arranged to form a die-croikt filter array 56.
- the dichroic mirror 41 is disposed at an angle of (45 + / 3) ° with respect to the optical axis La of the light source 20, and the reflection mirror 42 is arranged to be the light of the light source 20.
- the dichroic mirror 41 and the reflecting mirror 42 are arranged at an angle of (45_ ⁇ ) ° with respect to the axis La, and the axis Lc forms an angle of 45 ° with the optical axis La of the light source 20.
- the lens 63 of the second lens array 60 can be configured by integrating the concentric lens 61 and the eccentric lens 62 in Embodiment 1 described above into one.
- the second lens array 60 can be constituted by a product equivalent to the first lens array 30, and further cost reduction can be achieved.
- the incident angle (45 ⁇ 3) ° of the partial light beam on the dichroic mirror 41 can be made as small as 45 °, the dependence of the spectral characteristics of the dichroic mirror 41 on the incident angle can be reduced. Separation of the first color partial light beam and the second color partial light beam can be performed more accurately and reliably.
- a dichroic filter array 56 is provided on the incident side of the polarizing beam splitter array 51. Therefore, even when the dichroic mirror 41 having a relatively large incident angle dependency in the spectral characteristics is used, it is possible to prevent unnecessary color light from being incident on the polarization beam splitter array 51, and the partial light of the first color can be prevented. It is possible to reliably separate the light flux and the partial light flux of the second color. Note that the dichroic filter array 56 can also be arranged on the front surface of the second lens array 60.
- FIG. 4 shows another embodiment of the projector including the illumination optical system according to the present invention.
- This embodiment is different from the second embodiment described above mainly in the arrangement of the mirrors 41 and 42 of the color light separating optical element 40 and the configuration of the second lens array 60.
- Other configurations are the same as those of the second embodiment.
- light represented by a solid line represents P-polarized light
- light represented by a broken line represents S-polarized light.
- the dichroic mirror 41 of the color light separating optical element 40 is opposite to the dichroic mirror 41.
- the projection mirrors 42 are parallel to each other, and are arranged at intervals of a predetermined amount t along the direction of the optical axis La.
- the predetermined amount t is substantially equal to the distance between the polarization splitting film 54 and the reflection film 55 constituting the polarization beam splitter array 51 in the direction along the incident end face 51 a of the polarization beam splitter array 51.
- the dichroic mirror 41 and the reflection mirror 42 are both arranged at an angle of 45 ° with respect to the optical axis La of the light source 20.
- the partial light beam (G) of the first color and the partial light beam (B + R) of the second color are parallel to each other. Can be ejected to different positions. Accordingly, both the first color partial light beam (G) and the second color partial light beam (B + R) can be made to be incident perpendicularly to the second lens array 60, so that the second lens array 60. Can be composed of only concentric lenses 61. Thus, the configuration of the second lens array 60 can be simplified, and the cost can be further reduced.
- FIG. 5 shows another embodiment of the projector including the illumination optical system according to the present invention. This embodiment is different from Embodiment 2 described above in the configuration of the color separation / synthesis optical system. Also, the position of the two-wavelength plate 52 of the polarization conversion element 50 is different. Other configurations are the same as those of the second embodiment.
- a light ray indicated by a solid line indicates P-polarized light
- a light ray indicated by a broken line indicates S-polarized light.
- the; / 2 wavelength plate 52 of the polarization conversion element 50 is provided at a position where the light reflected by the reflection film 55 is emitted, and Rotate the plane of polarization 90 °.
- the color separation / synthesis optical system 130 is a rectangular parallelepiped first to fourth polarization beam splitters 140, 150, 160, 170 arranged in a cross shape.
- the first polarization beam splitter 140 is a rectangular parallelepiped optical element in which a polarized light separating film 144 is formed on the joint surface of two right-angle prisms 141 and 142, and the polarized light is polarized.
- the light separation film 144 is formed of a dielectric multilayer film or the like, and has, for example, polarization separation characteristics of transmitting only P-polarized light and reflecting S-polarized light.
- the other second to fourth polarization beam splitters 150, 160, 170 also have the same polarization separation characteristics as those of the first polarization beam splitter 140.
- 151, 152, 161, 162, 171, and 172 indicate right-angle prisms.
- the wavelength-selective phase difference plates 180 and 181 have optical characteristics as shown in FIG. 18 and do not change the phase of at least the transmitted red light. By imparting a phase change of // 2 to the transmitted blue light, the polarization direction of the blue light is rotated by 90 °.
- the entrance end surface 144 of the first polarizing beam splitter 140 faces the collimating lens 99 and faces the entrance surface of the illumination optical system 10 and the light.
- the reflection type liquid crystal panel 200 G is placed on the end face 154 opposite to the input side of the second polarizing beam splitter 150, and the two incident and emitting sides of the third polarizing beam splitter 160.
- Two reflective liquid crystal panels 200 B, 20 OR are arranged opposite to each other on the end surfaces 16 4 and 16 5, and the projection lens 2 10 is provided on the end surface 17 4 of the fourth polarization beam splitter 17 0 They are arranged facing each other.
- the partial beam (B + R) of the second color which is P-polarized light, passes through the polarized light separation film 144 of the first polarized beam splitter 140.
- the first color light (G) which is S-polarized light, is reflected by the polarized light separating film 144 and incident on the second polarized beam splitter 150.
- the second polarizing beam splitter 150 guides the partial light beam (G) of the first color, which is the S-polarized light from the first polarizing beam splitter 140, to the reflective liquid crystal panel 200G,
- the partial light flux (G) of the first color, which is light-modulated by the reflective liquid crystal panel 200 G and becomes P-polarized light, is guided to the fourth polarizing beam splitter 170.
- the wavelength-selective phase difference plate 180 controls only the polarization direction of the blue light, out of the blue light and the red light included in the partial light flux (B + R) of the second color from the first polarizing beam splitter 140. Turn about 90 °. As a result, the red light of the P-polarized light and the blue light of the S-polarized light enter the third polarizing beam splitter 160 and are separated by the difference in the polarization direction.
- the red light of the P-polarized light passes through the polarized light separating film 163 of the polarizing beam splitter 16 and reaches the reflective liquid crystal panel 200R, and the blue light of the S-polarized light is the polarized light separating film 1
- the light is reflected at 63 to reach the reflective liquid crystal panel 200B.
- the red light and the blue light modulated by the reflective liquid crystal panel 200 R and the reflective liquid crystal panel 200 B return to the third polarizing beam splitter 160 and are combined to form a wavelength selection position. It is incident on the phase difference plate 18 1.
- the polarization direction of the blue light is approximately 90 °. Rotate.
- the S-polarized light red light and the S-polarized light blue light enter the fourth polarizing beam splitter 170.
- the polarization beam splitting film 1 73 of the fourth polarization beam splitter 170 transmits the P-polarized light of the green light of the second polarization beam splitter 150 and the green light of the third polarization beam splitter 170.
- the red light of the S-polarized light and the blue light of the S-polarized light are reflected, and these three color lights are combined and emitted toward the projection lens 210.
- the same effect as in the above-described embodiment can be obtained. Furthermore, in the present embodiment, since all the color lights pass through the two polarizing beam splitters and reach the projection lens 210, the contrast of the projected image of the projector can be increased.
- the partial light flux (G) of the first color is P-polarized light
- the partial light flux (B + R) of the second color is S-polarized light
- the blue light is placed on the second polarizing beam splitter 150 side.
- a reflective liquid crystal panel for green light are disposed on the side of the third polarizing beam splitter, and two reflective liquid crystal panels for red light and red light. It is good also as composition.
- the contrast of green light can be further increased, so that a projected image with higher contrast can be displayed.
- the dichroic mirror 41 and the reflecting mirror 42 of the color light separating optical element 40 are arranged at the angles described in the second embodiment. However, in the first embodiment and the third embodiment, May be arranged at the angle described in the above.
- the first polarizing beam splitter 140 reflects a green light (G) and transmits a red light (R) and a blue light (B) to a dichroic mirror or a dichroic prism.
- the polarizing beam splitter 170 can be replaced by a dichroic mirror or a dichroic prism that transmits only green light (G) and reflects red light (R) and blue light (B). Further, when the latter is adopted, the wavelength selection phase difference plate 181 can be omitted. Adopting such a configuration is convenient in that cost reduction can be easily realized.
- FIG. 6 shows a fifth embodiment of a projector including the illumination optical system according to the present invention.
- This embodiment is different from the first to fourth embodiments in that a transmission type light modulator and a corresponding color separation optical system and color synthesis optical system are used.
- the illumination optical system 10 of the present embodiment the illumination optical system 10 used in any of the embodiments 1 to 4 can be applied. In this embodiment, a configuration to which illumination optical system 10 of Embodiment 1 is applied will be described as a representative example.
- the position of the ⁇ 2 wavelength plate 52 is shifted from the position indicated by the illumination optical system 10 in FIG. 1 to an adjacent position.
- the first color partial light beam (G) can be emitted as S-polarized light
- the second color partial light beam (B + R) can be emitted as ⁇ -polarized light.
- the same parts as those in the first embodiment are denoted by the same reference numerals as those in FIG. 1, and duplicate description is omitted.
- the light ray indicated by a solid line indicates ⁇ -polarized light
- the light ray indicated by a broken line indicates an S-polarized light. ing.
- the partial light flux (G) of the first color which is S-polarized light
- the partial light beam (G) of the first color from the illumination optical system 10 enters the dichroic mirror 501.
- the dichroic mirror 501 is set to have optical characteristics of transmitting red light and reflecting green light and blue light.
- the green light reflected by the dichroic mirror 503 enters the dichroic mirror 503.
- the dichroic mirror 503 is set to have optical characteristics of transmitting blue light and reflecting green light.
- the green light reflected by the dichroic mirror 503 enters the transmission light modulator for green light 520 G via the collimating lens 51 OG, and the transmission light modulator 520 G
- the light is modulated according to external image information (not shown), and is emitted as P-polarized light depending on the degree of modulation.
- a pair of polarizers are arranged before and after the three transmissive light modulators described below to increase the degree of polarization of the incident light on the incident side and to eliminate unnecessary polarized light on the exit side. However, the notation is omitted in FIG.
- the red light of the partial light flux (B + R) of the second color light enters the dichroic mirror 501.
- the red light transmitted through the dichroic mirror 501 is bent by approximately 90 ° in the optical path by the reflection mirror 502, the light is transmitted through the collimating lens 51 OR and the transmission type light modulator 5 for red light 5 It is incident on 20 R.
- the red light which is the P-polarized light incident on the transmission light modulator 52 O, is modulated by the transmission light modulator 52 OR in accordance with external image information (not shown), and S-polarized depending on the degree of modulation. Emitted as light.
- the second color partial light beam (B + R) from the illumination optical system 10 enters the dichroic mirror 501.
- the blue light reflected by the dichroic mirror 501 passes through the dichroic mirror 503, the first relay lens L1, the reflecting mirror 504, the second relay lens L2, and the reflecting mirror 5 0 Relay optical system consisting of 5 and collimating lens 5
- the light enters the transmission light modulator for blue light 52 OB via 10 B.
- Blue light which is P-polarized light incident on the transmission type optical modulator 520B, is modulated in accordance with an image signal like red light, and is emitted as S-polarized light.
- the reason for using a relay optical system for the blue light path is that the optical paths of the other two color lights are made approximately the same in optical path length to suppress the occurrence of color unevenness and brightness unevenness. It is.
- the cross dichroic prism 530 has a blue light reflecting dichroic opening film 53 OB and a red light reflecting dichroic film 53 OR each at an angle of 45 ° with respect to the incident optical axis, and They are arranged in an X-shape so as to be orthogonal.
- the three color lights incident on the cross dichroic prism 530 which is a color synthesizing optical system, are synthesized and color synthesized. Then, the combined light projects and displays a full-color image on a screen (not shown) by the projection lens 540.
- a cross dichroic prism is often used as a color combining optical system.
- the color light reflected by the dichroic film of the cross dichroic prism is set to S-polarized light, and the color light transmitted through the dichroic film is set to P-polarized light, the light use efficiency during color synthesis is improved. It is convenient in that it is performed. Therefore, in the present embodiment, the light emitted from the transmission light modulator for green light 520 G is emitted from the transmission light modulator for P-polarized light, red light and blue light 52 OR, B. Since the emitted light is configured to be S-polarized light, a bright projected image can be obtained. (Embodiment 6)
- FIG. 7 shows another embodiment of the illumination optical system according to the present invention.
- the illumination optical system 1OA according to the present embodiment has a color separation 'combination optical system 100 as shown in FIGS. 1, 3, and 4, and a color separation as shown in FIG. ⁇ Synthesis optical system 130, color separation optical system and color synthesis optics premised on transmission type light modulator as shown in Fig. 6 It is possible to combine with any of the systems.
- the illumination optical system 10 A according to this embodiment is different from the illumination optical system 10 in that a color light separation optical element 40 is provided between a light source 20 and a first lens array 30 which is a light beam splitting optical element. This is different from the illumination optical system 10 according to mode 2.
- Other configurations are the same as those of the illumination optical system 10 according to the second embodiment.
- first color light (G) and second color light (B + R) are respectively emitted in slightly different directions.
- the first color light (G) and the second color light (B + R) incident on the first lens array 30 are divided into a plurality of partial light beams by the respective small lenses 31 and condensed.
- the partial beam (G) of the first color is applied to the reflection film 55 of the polarization beam splitter array 51 of the polarization conversion element 50, and the partial beam (B + R) of the second color is polarized.
- the light enters the polarization separation film 54 of the light beam splitter array 51.
- partial luminous fluxes are: after being aligned by the L-nozzle two-wave plate 52, the partial luminous flux of the second color (B + R) is made into S-polarized light, and the partial luminous flux of the first color (G) is made into P-polarized light. Are superimposed on the illuminated area by the superimposing lens 70.
- the illumination optical system 10OA has the same operation and effects as those of the illumination optical system 10 according to the second embodiment.
- the color light separating optical element 40 is arranged between the light source 20 and the first lens array 30 and the light beam with high parallelism enters the color light separating optical element 40, Compared with the other embodiments, the color light separating optical element 40 can surely separate the color light with higher efficiency.
- the dichroic mirror 41 and the reflection mirror 42 of the color light separating optical element 40 are arranged at an angle as described in the second embodiment. It may be arranged at an angle as described in the third embodiment.
- FIG. 8 shows the structure of a polarization conversion element 5OA according to a modification of the illumination optical system according to the present invention.
- FIG. This polarization conversion element 5 OA is different from the polarization conversion element 50 shown in FIG. 2 in that the polarization conversion element 5 OA is composed of only the polarization separation film 54 without using the reflection film 55 (FIG. 2).
- Other configurations are the same as those of illumination optical system 10 according to Embodiment 2.
- parts corresponding to those in FIG. 2 are denoted by the same reference numerals as those in FIG. 2, and description thereof will be omitted.
- the polarizing beam splitter array 51 has a configuration in which a plurality of columnar translucent members 53 having a parallelogram cross section are bonded together as in FIG.
- a polarization separation film 54 is provided at a predetermined interval d at the bonding interface between the adjacent translucent members 53.
- the predetermined distance d is equal to the distance between the polarization separation film 54 and the reflection film 55 in the polarization conversion element 50 described above.
- the polarization separation film 54 is inclined by about 45 ° with respect to the incident end face 51a of the polarization conversion element 5OA.
- the number of the polarization separation films 54 corresponds to approximately twice the number N of columns or the number M of rows of the first lens array 30. In other words, the number of the polarization separation films 54 of the polarization conversion element 5OA is substantially equal to the sum of the numbers of the polarization separation films 54 and the reflection films 55 in the polarization conversion element 50.
- the X / 2-wavelength plates 52 are arranged at a pitch of 2 d with a predetermined interval d, corresponding to every other polarization separation film 54.
- the polarization conversion element 5 OA includes a partial light beam of the second color (for example, the second color light beam incident on the incident end face ⁇ ⁇ where the ⁇ / 2 wavelength plate 52 is disposed behind (the exit side) the polarization separation film 54. B + R) is converted into S-polarized light as polarized light having the second polarization direction. Further, the polarization conversion element 5 OA is provided behind the polarization separation film 54 (on the emission side); the first-color partial light flux (for example, G) incident on the incident end face BB where the LZ 2 wavelength plate 52 is not disposed. Is converted into P-polarized light as polarized light having the first polarization direction.
- the first-color partial light flux for example, G
- the second color partial light beam (B + R) incident on the polarization splitting film 54 from the incident end face AA of the polarizing beam splitter array 51 is divided into P-polarized light transmitted through the polarized light splitting film 54 and S-polarized light reflected. Is separated into The P-polarized light transmitted through the polarization separation film 54 is polarized by passing through the two-wavelength plate 52. The direction is rotated 90 ° and converted to S-polarized light. On the other hand, the S-polarized light reflected by the polarization separation film 54 is reflected again by the adjacent polarization separation film 54 and is emitted without passing through the wave plate 52.
- the polarization direction does not change and remains S-polarized light. Therefore, the second-color partial light beam (B + R) incident on the polarization separation film 54 from the incident end face AA is aligned with the S-polarized light and emitted from the polarization conversion element 5OA.
- the partial beam (G) of the first color that has entered the polarization separation film 54 from the incident end surface BB of the polarization beam splitter array 51 is composed of P-polarized light transmitted through the polarization separation film 54 and S-polarized light reflected. Is separated into The P-polarized light transmitted through the polarization separation film 54 is emitted without passing through the two-wavelength plate 52. For this reason, the polarization direction does not change and remains P-polarized light.
- the S-polarized light reflected by the polarization separation film 54 is reflected again by the adjacent polarization separation film 54, and passes through the two-wavelength plate 52 to rotate the polarization direction by 90 °. The P-polarized light is converted. Therefore, the partial light flux (G) of the first color that has entered the polarization splitting film 54 from the incident end surface BB is aligned with the P-polarized light and emitted from the polarization conversion element 5OA.
- light rays indicated by solid lines indicate P-polarized light
- light rays indicated by broken lines indicate S-polarized light
- the first color partial light beam (for example, G) is incident on the incident end face AA, and all the first color partial light rays emitted from the polarization conversion element 5OA are converted into S-polarized light, and the incident end face is also incident.
- a configuration may be adopted in which a second color partial light beam (for example, B + R) is made incident on BB, and all the second color partial light beams emitted from the polarization conversion element 5OA are converted into P-polarized light.
- the partial luminous fluxes of the first and second colors are selectively incident on the adjacent incident end faces AA and BB in accordance with the presence or absence of the two-wavelength plate 52.
- the polarization conversion element 5OA the partial light flux having the shortest optical path length and the longest optical path length among the partial light fluxes of the first color and the second color in the polarization conversion element are compared with the polarization conversion element 50 described above.
- the optical path length difference with the partial light beam having For this reason, in the illuminated area, the magnification of the partial luminous flux of the first color can be easily matched with the magnification of the partial luminous flux of the second color. As a result, partial light beams can be superimposed and combined with high illumination efficiency.
- the polarization beam splitter array 51 in the polarization conversion element 50 has a polarization separation film and a reflection film, whereas the polarization beam splitter array 51 in the polarization conversion element 5 OA has only a polarization separation film. Therefore, the structure of the polarizing beam splitter array is simple and easy to manufacture.
- FIGS. 9 (a) and 9 (b) show another embodiment of the color light separating optical element. These color light separation optical elements can be replaced with the color light separation optical elements 40 in the illumination optical systems 10 and 1OA described above.
- the color light separating optical element shown in FIGS. 9 (a) and 9 (b) has a dichroic mirror 81 provided on one surface of a translucent member 80 having two opposing surfaces, and the other surface. It is configured as one optical component in which a reflection mirror 82 is provided.
- the color light separation optical element shown in FIGS. 10A and 10B has a configuration in which a right-angle prism 84 is fixed to one surface of a light-transmitting member 83 having two opposing surfaces. ing.
- a dichroic mirror 85 is provided between the translucent member 83 and the right-angle prism 84, and a reflection mirror 86 is provided on the other surface of the translucent member 83.
- a plurality of small-dimension right-angle prisms 88 are formed in a step shape on one surface of a light transmitting member 87 having two opposing surfaces. It is configured to be fixed to the.
- a dichroic mirror 89 is provided between the translucent member 87 and the small-size right-angle prism 88, and a reflection mirror 90 is provided on the other surface of the translucent member 87.
- the dichroic mirrors 81, 85 and 89 and the reflecting mirrors 82, 86 and 90 are not connected. They are arranged so as to be (45 + i3) ° and (45-j3) ° with respect to the optical axis La of the light source, respectively.
- the dichroic mirrors 81, 85, 89 and the reflecting mirrors 82, 86, 90 are respectively 45 ° and (45- ⁇ ) ° with respect to the optical axis La of the light source. You may arrange so that it may be.
- the dichroic mirrors 81, 85, 89 and the reflecting mirrors 82, 86, 90 are used in the color light separating optical elements shown in FIGS. 9 (b), 10 (b) and 11 (b).
- the dichroic mirrors 81, 85, 89 and the reflecting mirrors 82, 86, 90 are used in the color light separating optical elements shown in FIGS. 9 (b), 10 (b) and 11 (b).
- the dichroic mirrors 81, 85, 89 and the reflecting mirrors 82, 86, 90 are used. Are parallel and are arranged at 45 ° to the optical axis La of the light source. How to set the above-mentioned installation angles for the dichroic mirror and the reflection mirror is as described in the above embodiment.
- the dichroic mirrors 81, 85, and 89 as the first mirror correspond to the dichroic mirror 41 of the color light separating optical element 40, and can be configured in the same manner.
- the reflecting mirrors 82, 86, 90 as the second mirror correspond to the reflecting mirror 42 of the color light separating optical element 40, and can be configured in the same manner.
- color light separation optical elements are configured as one optical component. Therefore, if these color light separating optical elements are used, assembly of the device can be facilitated. Further, the color light separating optical element shown in FIGS. 10 (a) and 10 (b) is a dichroic mirror since light is incident on the dichroic mirror 85 through a right angle prism 84 having a refractive index larger than 1. 8 The incident angle of light to 5 is narrowed, the spectral characteristics of the dichroic mirror 85 can be improved, and if the refractive indexes of the right-angle prism 84 and the translucent member 83 are made to match, the right-angle prism 84 changes to the dichroic mirror 85.
- the color light separating optical elements shown in FIGS. 11 (a) and 11 (b) have the same characteristics as the color light separating optical elements shown in FIGS. 10 (a) and 10 (b).
- the size of the prism can be reduced, so that the color light separating optical element can be reduced in size and weight.
- the dichroic mirror and the reflecting mirror are Must be set in consideration of the refractive index of the intervening medium.
- Figure 9 In the color light separation optical element described above, when light enters the medium from the air, the light is refracted and an optical path shift occurs.
- the color light separation optical element shown in FIG. 12 is composed of a reflection type hologram element 91, and the color light separation optical element shown in FIGS. 13 and 14 is a transmission type hologram element. It is composed of a program element 92.
- FIGS. 12 to 14 parts corresponding to FIGS. 1 and 3 are denoted by the same reference numerals as those in FIGS. 1 and 3, and the description thereof is omitted.
- the reflection hologram element 91 and the transmission hologram element 92 can be arranged either before or after the first lens array 30, which is a light beam splitting optical element. Further, regardless of the reflection type or the transmission type, the direction of the separated light can be symmetric or asymmetric with respect to the optical axis Lb.
- FIG. 12 and 13 show examples of the case of symmetry
- FIG. 14 shows an example of the case of asymmetric.
- a second lens array 60 consisting of only the concentric lenses 63 shown in FIG. 3 can be used, while in the case of asymmetric, the concentric lenses 63 shown in FIG.
- the second lens array 60 composed of 1 and the eccentric lens 62 will be used.
- the use of the hologram element described above makes it possible to reduce the number of components of the color light separation optical element, and to reduce the size and weight of the illumination optical system and, consequently, the projector using the same. Become.
- a mirror array 94 in which small concave mirrors 93 are arranged in a matrix instead of the first lens array 30 is used as a light beam splitting optical element.
- the color light separating optical element is constituted by a transmission type hologram element 92.
- Second lens array 60 is the same as lens array 60 in the second embodiment. The parts shown in this figure are the same as the parts of the first lens array 30, the color light separating optical element 40, and the second lens array 60 shown in FIGS. 1, 3, 5, and 6. It is possible to replace it.
- the small concave mirror 93 works the same as the small lens 31 of the first lens array 30.
- the mirror array 94 functions in the same way as the first lens array 30 and, as compared with the case of the lens configuration, Become cheap. Further, in the mirror array 94, since spherical aberration is not generated, which is attached to the lens array, the light collecting property can be improved and the illumination efficiency can be improved.
- Color light separation by the color light separation optical element is not limited to separation of green light and blue + red light, but may be separation of blue light and green + red light, or separation of red light and green + blue light. .
- Such a combination of colors can be arbitrarily set by selecting the spectral characteristics of the dichroic mirror 41.
- the dichroic mirror 41 may have a spectral characteristic of selectively reflecting green light and transmitting other light. The effect of the combination of color light separation will be described using the projector according to the first embodiment shown in FIG. In the case of the combination of separation of blue light and green + red light, in FIG. 1, the reflection type liquid crystal panel for green light 200 A reflective liquid crystal panel 200R is arranged. In this case, the use efficiency of red light can be increased.
- the setting of the polarization direction of the first color light and the second color light is not limited to the above embodiment, and the polarization state may be arbitrarily changed according to the configuration of the color separation / combination optical system 100. Can be set. For example, align the first color light with S-polarized light and the second color light with P-polarized light Such an optical configuration can be adopted. In other words, when the ⁇ two-wave plate 52 is disposed behind (the emission side) the polarization separation film on which the specific color light is incident, the specific color light is converted into S-polarized light and emitted. If the half-wave plate 52 is not disposed behind (the emission side) the polarization separation film on which the specific color light is incident, the light of the specific color light is converted into ⁇ -polarized light and emitted.
- the partial light flux of the second color reflected by the dichroic mirror 141 of the color light separation optical element 40 is made incident on the polarization separation film 54 of the polarization conversion element 50, and the reflection mirror 4
- the partial light flux of the first color reflected by 2 is made to enter the reflection film 55, but the correspondence between the partial light fluxes of the first and second colors and the polarization separation film 54 and the reflection film 55 is as described above. The reverse may be true. That is, a configuration may be adopted in which the first color partial light beam is incident on the polarization splitting film 54 and the second color partial light beam is incident on the reflection film 55.
- the polarization conversion element 50 when used, between the first lens array 30 and the second lens array 60, and between the polarization conversion element 50 and the color separation / synthesis optical system 100. Considering the difference in the optical path length between the first color partial light flux and the second color partial light flux occurring between the above, the correspondence in the above embodiment is most appropriate. Incidentally, if the lens characteristics of the first and second lens arrays 30 and 60 are appropriately set, the pair of the polarization separation film 54 and the reflection film 55 will be located at the folded position with the optical axis Lb as the symmetry axis. It is also possible to use an arranged polarization conversion element.
- the angle between the optical axis La and the optical axis Lb is 90 °, and about 45 ° for the color light separating optical element 40.
- the angle between the optical axis L a and the optical axis L b is made smaller than 90 °, and the light from the light source 20 is It may be configured to be incident at an angle smaller than 45 ° with respect to 0. In that case, the spectral characteristics and the reflection characteristics of the dichroic mirror 41 and the reflection mirror 42 used in the color light separation optical element 40 can be easily improved, and high optical efficiency can be realized.
- the angle between the optical axis La and the optical axis Lb may be set to be larger than 90 °.
- a light guide rod having a plurality of reflecting surfaces can be used instead of the lens array 30 as the light beam splitting optical element.
- Such a light guide port is disclosed in, for example, Japanese Patent Application Laid-Open No. H10-161237, and is well known, so that detailed description thereof will be omitted. If a light guide rod is used, as in the case of the mirror array 94, spherical aberration is not generated, which is inherent in the lens array, so that the light collecting property can be improved and the illumination efficiency can be improved.
- the illumination optical system according to the present invention can be used as a device for illuminating various light modulation devices irrespective of a reflection type or a transmission type, as described in the above embodiments.
- the non-polarized light from the light source is converted into a polarized light beam in which the polarization direction is uniform for each color light in advance, so that the illumination optical system
- this illumination optical system in a projector, it is possible to achieve high brightness, high image quality, and high contrast of a projected image. Also, the number of parts can be reduced and cost can be reduced as compared with the case where a conventional illumination optical system is used. Industrial applicability
- illumination light in which the polarization direction of a specific color light differs from that of another color light by about 90 ° is efficiently generated, and the illumination light system is covered with such illumination light.
- the illumination area can be illuminated with a uniform illuminance distribution.
- the projector of the present invention by applying the above-described illumination optical system, the polarization dependence of the spectral characteristic on the dichroic surface constituting the color separation / synthesis optical system is reduced, and bright and high-quality projection is performed. Images can be displayed. Also, the number of components can be reduced and cost can be reduced as compared with the case where a conventional illumination optical system is used.
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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DE60215940T DE60215940T2 (de) | 2001-06-22 | 2002-06-24 | Optisches beleuchtungssystem und projektor |
KR1020037002606A KR100909926B1 (ko) | 2001-06-22 | 2002-06-24 | 조명 광학계 및 프로젝터 |
EP02743711A EP1398657B1 (en) | 2001-06-22 | 2002-06-24 | Illumination optical system and projector |
JP2003507615A JP3891178B2 (ja) | 2001-06-22 | 2002-06-24 | 照明光学系およびプロジェクタ |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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JP2001-190289 | 2001-06-22 | ||
JP2001190289 | 2001-06-22 |
Publications (1)
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WO2003001277A1 true WO2003001277A1 (fr) | 2003-01-03 |
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Application Number | Title | Priority Date | Filing Date |
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PCT/JP2002/006310 WO2003001277A1 (fr) | 2001-06-22 | 2002-06-24 | Systeme d'eclairage optique et projecteur |
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US (1) | US6739724B2 (ja) |
EP (1) | EP1398657B1 (ja) |
JP (1) | JP3891178B2 (ja) |
KR (1) | KR100909926B1 (ja) |
CN (1) | CN1310062C (ja) |
DE (1) | DE60215940T2 (ja) |
TW (1) | TWI224208B (ja) |
WO (1) | WO2003001277A1 (ja) |
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JP7219002B2 (ja) * | 2017-09-11 | 2023-02-07 | i-PRO株式会社 | 内視鏡 |
CN111837073B (zh) * | 2018-03-20 | 2022-10-11 | 索尼公司 | 图像显示设备 |
CN113031138B (zh) * | 2021-03-22 | 2022-12-06 | 腾景科技股份有限公司 | 一种基于合色且消偏振分光棱镜模组装置 |
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Also Published As
Publication number | Publication date |
---|---|
EP1398657B1 (en) | 2006-11-08 |
JPWO2003001277A1 (ja) | 2004-10-14 |
KR100909926B1 (ko) | 2009-07-29 |
DE60215940T2 (de) | 2007-09-06 |
KR20030028814A (ko) | 2003-04-10 |
CN1463376A (zh) | 2003-12-24 |
TWI224208B (en) | 2004-11-21 |
EP1398657A1 (en) | 2004-03-17 |
US6739724B2 (en) | 2004-05-25 |
EP1398657A4 (en) | 2004-09-08 |
JP3891178B2 (ja) | 2007-03-14 |
CN1310062C (zh) | 2007-04-11 |
US20030043348A1 (en) | 2003-03-06 |
DE60215940D1 (de) | 2006-12-21 |
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