JP2009003062A - Light source device and illuminating device having it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device, enabling downsizing of the entire device, making polarization states uniform to emit the light rays of the respective colors from the same direction, and illuminating a surface to be irradiated brightly and uniformly with the light rays of the respective colors, and an illuminating device having it. <P>SOLUTION: This light source device includes: a first, second and third light sources for emitting first, second and third color light rays; a first and second polarized light separation surfaces disposed non-parallel; a quarter-phase plate; and a reflection surface, wherein in emitting a beam of light obtained by synthesizing the first, second and third color light rays in the outgoing direction, these members are suitably disposed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a light source device and an illuminating device having the light source device, and is suitable for a liquid crystal projector that enlarges and projects a projected image based on a liquid crystal panel (image display element) on a screen surface.

  Conventionally, various image projection apparatuses (liquid crystal projectors) have been proposed in which a projected image original image based on an image display element such as a liquid crystal panel is enlarged and projected on a screen surface.

  As a liquid crystal projector, in a color liquid crystal projector, three image display elements based on an image of three color lights of R light, G light, and B light are each illuminated with color light obtained by color-separating light (light flux) from a light source means.

  And the structure which projects each color light through three image display elements on a screen surface with one projection lens (projection optical system) via a color synthetic | combination means is known.

  Conventionally, there has been a demand for downsizing of the entire image projection apparatus. Accordingly, there is a strong demand for miniaturization of the light source device used in the image projection apparatus.

  In such a background, there has been proposed an image projection apparatus using a light source device having a configuration in which the mounting density of light sources is high and light beams from light sources that emit a plurality of color lights are emitted in an arbitrary deflection direction (patent) Reference 1).

  The image projection apparatus of Patent Document 1 is configured by combining arbitrary two color LED light sources (LED lamps) from among LED light sources that emit R, G, and B color lights. The two LED lamps are arranged on the same plane so that their optical axes are parallel to each other.

  Two types of LED lamps having different emission colors are combined into one set, and a dichroic mirror, a quarter wavelength plate, and a polarizing beam splitter are sequentially combined to form one LED lamp unit.

  From one LED lamp unit, two color lights unified with one polarized light are emitted in a superimposed state.

  The LED lamps can be arranged closely, and the LED lamp units that emit two kinds of emission colors are arranged in a predetermined combination to obtain the emission intensity of each desired emission color.

  The light beams of the respective colors are superimposed on the irradiated surface using a condensing optical system. As a result, the irradiation light on the irradiated surface becomes white light.

In order to perform color display, each color light is sequentially emitted to illuminate the display panel (liquid crystal panel).
JP-A-2005-202210

  In recent years, there is a demand for an image projection apparatus that is small in size as a whole and that there is no color unevenness in a projected image.

  In order for the entire apparatus to be small, it is important to appropriately set the configuration of the light source means that constitutes the illumination device that illuminates the liquid crystal panel.

  Also, in order to prevent color unevenness in the projected image, it is important to illuminate the liquid crystal panel with the emission direction of each color light emitted from the light source device aligned.

  If the emission direction differs for each color light, the irradiated surface cannot be illuminated in the same state with each color light, and color unevenness is likely to occur in the projected image.

  In particular, in the case of a color liquid crystal projector, color unevenness tends to occur in a projected image unless the liquid crystal panel is illuminated from the same direction with R, G, and B light.

  In addition, in order to increase the light utilization efficiency and brightly illuminate the irradiated surface, it is important to set the configuration of the light source device appropriately and to emit light with the polarization state aligned while reducing the overall size. .

  The present invention provides a light source device that can emit light of each color from the same direction with the polarization state aligned while reducing the size of the entire device, and can illuminate the illuminated surface brightly and uniformly with each color light, and An object of the present invention is to provide a lighting device having the same.

The light source device of the present invention comprises:
A first light source emitting a first color light;
A second light source that emits second color light;
A third light source that emits third color light;
A first polarization separation surface;
A second polarization separation surface disposed non-parallel to the first polarization separation surface;
A quarter phase plate,
A reflective surface;
A light source device that emits a light beam obtained by combining the first, second, and third color lights in the emission direction,
Of the third color light, the first partial light of the first polarized light is incident on the first polarization separation surface from the third light source side, reflected by the first polarization separation surface, and guided in the emission direction. ,
The second partial light of the second polarized light whose polarization direction is orthogonal to the first polarized light of the third color light is transmitted through the first polarized light separation surface and the second polarized light separation surface, and the 1/4 position After rotating the polarization direction by 90 degrees through the phase difference plate, the reflection surface, and the quarter phase difference plate again, it is incident on the surface opposite to the third light source of the second polarization separation surface, Reflected by the second polarization separation surface and guided in the emission direction;
The first polarization separation surface receives the first partial light and the first color light and the second color light that are incident on the first polarization separation surface from a direction different from the incident direction of the light beam from the third light source. Guiding the combined luminous flux in the emission direction;
The second polarization separation surface receives the second partial light and the first color light and the second color light incident on the second polarization separation surface from a direction different from the direction of incidence of the light beam on the third light source side. The synthesized light flux is guided in the emission direction.

In addition, the light source device of the present invention is
Three light sources that emit different colored light,
A polarization conversion means for aligning and combining the polarization states of the light beams from the three light sources, a λ / 4 plate, and a reflection surface;
A light source device that emits a light beam through the polarization conversion means in an emission direction,
The polarization conversion means includes a first prism element including a first polarization separation surface having a polarization separation action for a predetermined color light, and a second prism element including a second polarization separation surface. And
Each of the first and second prism elements has four transmission surfaces, and the first and second polarization separation surfaces are 45 ° with respect to the respective transmission surfaces inside the first and second prisms. Are arranged at an angle,
Of the four transmission surfaces of each of the first and second prisms, one transmission surface 1a, 2a constitutes the exit surface of the polarization converting means,
The first prism element and the second prism element are arranged so that each one transmission surface is close to or bonded to each other,
At least one of the three light sources is disposed such that the light source optical axis is orthogonal to the normal direction of the exit surface,
The light beam from the one light source is incident from a surface different from the transmission surface 1a of the first prism element, and the light in the first polarization direction is directed toward the transmission surface 1a on the first polarization separation surface. Is reflected, and light in the second polarization direction orthogonal to the first polarization direction is incident on the second prism element,
The light having the second polarization direction incident on the second prism element is transmitted through the λ / 4 plate through the second polarization separation surface, reflected by the reflection mirror, and again the λ / 4 plate. , And re-enters the second prism element as light in the first polarization direction, and the light is directed toward the transmission surface 2a of the second prism element via the second polarization separation surface. Reflected,
The light from the light sources other than the one light source is the four transmissive surfaces of the first and second prism elements that are transmitted while the light from the one light source reaches the transmissive surfaces 1a and 2a. The light is incident from a transmission surface different from the three transmission surfaces, and is emitted from the transmission surfaces 1a and 2a via the first and second polarization separation surfaces, respectively.

In addition, the light source device of the present invention is
Three light sources that emit different colored light,
A polarization conversion means for aligning and combining the polarization states of the light beams from the three light sources, a λ / 4 plate, and a reflection surface;
A light source device that emits a light beam through the polarization conversion means in an emission direction,
The polarization conversion means includes a first prism element including a first polarization separation surface having a polarization separation action for a predetermined color light, and a second prism element including a second polarization separation surface. And
The first prism element has transmission surfaces 1a, 1b, 1c, and 1d, and the second prism element has transmission surfaces 2a, 2b, 2c, and 2d, and the first and second polarization separation surfaces are the first and second polarization separation surfaces. , Are arranged at an angle of 45 ° with respect to the respective transmission surfaces inside the second prism,
The transmission surfaces 1a and 2a constitute the exit surface of the polarization conversion means,
The transmission surfaces 1b and 2b are arranged to face each other,
At least one of the three light sources is disposed such that the light source optical axis is orthogonal to the normal direction of the exit surface,
The light beam from the one light source is incident from the transmission surface 1c, and the light in the first polarization direction is reflected toward the transmission surface 1a at the first polarization separation surface,
Light having a second polarization direction orthogonal to the first polarization direction is transmitted through the transmission surfaces 1b and 2b and enters the second prism element, and the light having the second polarization direction incident on the second prism element. The light is transmitted through the transmission surface 2c and the λ / 4 plate through the second polarization separation surface, reflected by the reflection mirror, and again transmitted through the λ / 4 plate and the transmission surface 2c. Re-enters the second prism element as light in the first polarization direction, and the light is reflected toward the transmission surface 2a through the second polarization separation surface,
Light from a light source other than the one light source passes through the transmission surfaces 1d and 2d and is incident on the first and second prism elements, and passes through the first and second polarization separation surfaces, respectively. It is characterized by being emitted from the surfaces 1a and 2a.

  According to the present invention, it is possible to emit light of each color from the same direction with the polarization state aligned while reducing the size of the entire apparatus, and to illuminate the irradiated surface brightly and uniformly with each color light. A device and a lighting device having the device are obtained.

  FIG. 1 shows an essential part of Embodiment 1 of an image projection apparatus for projecting an image display element (liquid crystal panel) illuminated with a light beam from a lighting apparatus having a light source device of the present invention onto a predetermined surface using a projection optical system. FIG.

  In FIG. 1, reference numeral 22 denotes a light source device that emits white light by combining the emission directions of the respective color lights. Reference numerals 18 and 20 are polarizing plates, 19 is a liquid crystal panel (image display element), and 15 is a projection optical system.

  The light source device 22 of the present invention includes a first light source 1 that emits first color light, a second light source 2 that emits second color light, and a third light source 3 that emits third color light. Furthermore, it has a first polarization separation surface, a second polarization separation surface arranged non-parallel to the first polarization separation surface, a quarter phase plate (λ / 4 plate) 5, and a reflection surface 6. In addition, a light beam obtained by combining the first, second, and third color lights is emitted in the emission direction.

  The light source device 22 is an LED light source (R light source, first light source) 1 that emits red (first color light), an LED light source (G light source, second light source) 2 that emits green (second color light), and blue (third color light). LED light source (B light source, third light source) 3 that emits light. Further, prism elements 42 to 47 including separation films (polarization separation surfaces) 7 to 12, λ / 4 plate (1/4 phase difference plate) 5, and reflection mirror (reflection surface) 6 are provided.

  The optical action in the light source device 22 is as follows.

  Reference numeral 17 denotes the direction of illumination light (outgoing direction) emitted from the light source device 22 to the liquid crystal panel 19 and corresponds to the optical axis of the projection optical system 15.

  The LED light source (R light source) 1 that emits red light (R light) is arranged so that the optical axis 14R, which is the direction in which the light from the LED light source 1 radiates, is orthogonal to the direction (illumination direction) 17 of illumination light. Yes.

  The red random polarized light R emitted from the LED light source 1 enters the prism element 42 and enters the separation film 7.

  The separation film 7 has the optical characteristics shown in FIG. 2 (schematically shown, the same applies hereinafter), and has a polarization separation function for red light (wavelength 600 nm to wavelength 700 nm).

  Therefore, the S-polarized light (first polarized light) Rs1 of the incident light is reflected by the separation film 7 and travels in the direction 17 of the illumination light.

The S-polarized light Rs 1 reflected from the separation film 7 enters the prism element 44 and enters the separation film 9.
The separation film 9 has the optical characteristics shown in FIG. 3, and transmits the red S-polarized light Rs1. The S-polarized light Rs1 that has passed through the separation film 9 enters the prism element 46 and enters the separation film 11. The separation film 11 has the optical characteristics shown in FIG. 4 and transmits the red S-polarized light Rs1.

  As a result, the S-polarized light Rs1 is emitted from the surface 13 which is the emission surface of the light source means 22.

  Further, the red P-polarized light (second polarized light) Rp 1 that has passed through the separation film 7 passes through the separation film 7, enters the prism element 43, and enters the separation film 8.

  The separation film 8 has the optical characteristics shown in FIG. 2, and the red P-polarized light Rp1 passes through the separation film 8 and enters the λ / 4 plate 5.

  The λ / 4 plate 5 has a fast axis tilted by approximately 45 ° with respect to the polarization vibration direction, and the P-polarized light Rp1 is converted into circularly polarized light, reflected by the reflecting mirror 6, and again on the λ / 4 plate 5. Incident light is converted to S-polarized light and becomes S-polarized light Rs2. The S-polarized light Rs2 is reflected by the separation film 8 and travels in the direction 17 of the illumination light.

  The S-polarized light Rs 2 reflected from the separation film 8 enters the prism element 45 and enters the separation film 10. The separation film 10 has the optical characteristics shown in FIG. 3, and transmits the red S-polarized light Ps2. The S-polarized light Rs 2 that has passed through the separation film 10 enters the prism element 47 and enters the separation film 12.

  The separation film 12 has the optical characteristics shown in FIG. 4 and transmits the red S-polarized light Rs2. As a result, the S-polarized light Rs2 is emitted from the surface 13 which is the emission surface of the light source device 22.

  The LED light source (G light source) 2 emitting green (G light) (wavelength 500 nm to wavelength 600 nm) is set so that the optical axis 14G, which is the direction in which the light from the LED light source 2 radiates, is orthogonal to the direction 17 of the illumination light. Is arranged.

  The green random polarized light G emitted from the LED light source 2 enters the prism element 44 and enters the separation film 9.

  The separation film 9 has the optical characteristics shown in FIG. 3, and has a polarization separation action for green light. Accordingly, the S-polarized light Gs1 of the incident light is reflected by the separation film 9 and travels in the direction 17 of the illumination light.

  The S-polarized light Gs 1 reflected from the separation film 9 enters the prism element 46 and enters the separation film 11.

  The separation film 11 has the optical characteristics shown in FIG. 4 and transmits green S-polarized Gs1 light. Thus, the S-polarized light Gs1 is emitted from the surface 13 which is the emission surface of the light source device 22.

  Further, the green P-polarized light Gp1 that has passed through the separation film 9 passes through the separation film 9, enters the prism element 45, and enters the separation film 10.

  The separation film 10 has the optical characteristics shown in FIG. 3, and the green P-polarized light Gp1 passes through the separation film 10 and enters the λ / 4 plate 5.

  The λ / 4 plate 5 has a fast axis inclined by approximately 45 ° with respect to the polarization vibration direction, and the polarized light Gp1 is converted into circularly polarized light, reflected by the reflection mirror 6, and incident on the λ / 4 plate 5 again. Then, it is converted to S-polarized light and becomes S-polarized light Gs2. The S-polarized light Gs2 is reflected by the separation film 10 and travels in the direction 17 of the illumination light.

  The S-polarized light Gs 2 reflected from the separation film 10 enters the prism element 47 and enters the separation film 12. The separation film 12 has the optical characteristics shown in FIG. 4 and transmits green S-polarized light Gs2.

  As a result, the S-polarized light Gs <b> 2 is radiated from the surface 13 that is the emission surface of the light source device 22. The LED light source (B light source) 3 emitting blue (B light) (wavelength 400 nm to wavelength 500 nm) is arranged so that the optical axis 14B, which is the direction in which the light from the LED light source 3 radiates, is orthogonal to the direction 17 of the illumination light. Is arranged.

  The blue random polarized light B emitted from the LED light source 3 enters the prism element 46 and enters the separation film (first polarization separation surface) 11.

  The separation film 11 has the optical characteristics shown in FIG. 4 and has a polarization separation action for blue light. Therefore, the first partial light of the S-polarized light (first polarized light) Bs1 of the incident light is reflected by the separation film 11 and travels in the direction (outgoing direction) 17 of the illumination light.

  Thereby, it radiates | emits from the surface 13 which is an output surface of the light source device 22. FIG. Further, the second partial light of the blue P-polarized light (second polarized light) Bp1 that has passed through the separation film 11 is transmitted through the separation film 11 and incident on the prism element 47, and the separation film (second polarization separation surface) 12. Is incident on.

  The first polarization separation surface 11 and the second polarization separation surface 12 constituting the polarization conversion means are orthogonal to each other.

  The separation film 12 has the optical characteristics shown in FIG. 4, and the blue P-polarized light Bp1 passes through the separation film 12 and enters the λ / 4 plate 5.

  The λ / 4 plate 5 has a fast axis tilted by approximately 45 ° with respect to the vibration direction of the polarized light, the light is converted into circularly polarized light, reflected by the reflection mirror 6, and incident on the λ / 4 plate 5 again. It is converted to S-polarized light and becomes S-polarized light Bs2. The S-polarized light Bs2 is reflected by the separation film 12 and travels in the direction 17 of the illumination light.

  As a result, the S-polarized light Bs2 is emitted from the surface 13 which is the emission surface of the light source device 22.

  At this time, the polarization states of the first, second, and third color lights emitted from the emission direction 17 are the same.

  As described above, in the present embodiment, the first partial light of the first polarized light out of the third color light from the third light source 3 is incident on the first polarization separation surface 11 from the third light source side 3 and the first polarized light. The light is reflected by the separation surface 11 and guided in the emission direction.

  Of the third color light, the second partial light of the second polarized light whose polarization direction is orthogonal to the first polarized light is transmitted through the first polarized light separation surface 11 and the second polarized light separation surface 12, and the ¼ phase plate 5. The reflective surface 6 passes through the quarter phase plate 5 again.

  As a result, the polarization direction is rotated by 90 degrees. Thereafter, the light enters the second polarization separation surface 12 from the opposite side of the third light source 3, is reflected by the second polarization separation surface 12, and is guided in the emission direction 17.

  The first polarization separation surface 11 combines the first partial light and the first color light and the second color light incident on the first polarization separation surface 11 from a direction different from the incident direction of the light beam from the first light source 3. Is guided in the emission direction 17.

  The second polarization separation surface 12 combines the second partial light and the first color light and the second color light incident on the second polarization separation surface 12 from a direction different from the incidence direction of the light beam on the third light source 3 side. Is guided in the emission direction 17.

  Next, the configuration of the light sources 1, 2, and 3 will be described with reference to FIG.

  FIG. 12 shows one of the light sources 1, 2 and 3 as the light source unit 40.

  The light source unit 40 includes a light emitting unit 41 and a collimating lens 42. Diffused light contained in the luminous flux from the light emitting section 41 is emitted as light parallel to the light source optical axes (14R, 14G, 14B) by the collimating lens. In the drawings used for explaining each embodiment, the light beam is indicated by a thin line for simplicity.

  Here, the optical axis (light source optical axis) 14B of the light source (blue LED light source 3 in this embodiment) that emits the color light that is polarized and converted by the polarization conversion unit (polarization conversion means) having the prism elements 46, 47, etc. It is orthogonal to the radiation direction 17 of the illumination light.

  Further, as shown in FIG. 14, the prism element (first prism element) 46 constituting the polarization conversion unit is provided with four transmission surfaces. The first is a surface 46a (transmission surface 1c) on which blue light is incident, and the second is a surface 46b (transmission surface 1a) from which the first polarized light (S-polarized light) of blue light and other color light are emitted. It is. A third surface 46c (transmission surface 1b) faces the prism element (second prism element) 47 and emits blue second polarized light (P-polarized light). The fourth is a surface 46d (transmission surface 1d) on which red and green light other than blue light is incident. These four transmission surfaces 46a, 46b, 46c, 46d (transmission surface 1c, transmission surface 1a, transmission surface 1b, transmission surface 1d) are different surfaces of the prism element 46 (first prism element), respectively. It is a plane parallel to a straight line (a straight line perpendicular to the paper surface of FIG. 14).

  Further, the prism element (second prism element) 47 is also provided with four transmission surfaces. The first one is a surface 47a (transmission surface 2b) that is disposed facing the prism element 46 (first prism element) and on which blue light of the second polarized light (P-polarized light) is incident. The second is a surface 47c (transmission surface 2a) from which the first polarized light (S-polarized light) of blue light and other color light are emitted. The third is a transmission surface 47b (transmission surface 2c) from which the blue light of the second polarized light (P-polarized light) is emitted and incident again through the λ / 4 plate 5 and the mirror 6. The fourth is a surface 47d (transmission surface 2d) on which red and green light other than blue is incident. These four transmission surfaces 47a, 47b, 47c, 47d (transmission surface 2b, transmission surface 2c, transmission surface 2a, transmission surface 2d) are different surfaces of the prism element 47 (second prism element), respectively. It is a plane parallel to a straight line (a straight line perpendicular to the paper surface of FIG. 14).

  In this embodiment, the opposing surfaces of the prism elements 46 and 47 are bonded to each other. However, the surfaces are not limited to this, and they may be close to each other, or may be close to each other even if they are not bonded. It ’s enough.

  Since the red and green light incident on the plurality of prism elements 46 and 47 is emitted in the direction 17 in which the illumination light is emitted from the illumination light exit surface 13 in this way, the three colors of light are combined so as to overlap. It will be.

  In this embodiment, the prism elements 46 and 47 constituting the polarization conversion means are shown as different elements. However, as shown in FIG. 13, the prism element 46 and the adjacent surfaces (46c and 46d) of the prism element 47 are integrated. It is also good.

  In this case, the operation of the present embodiment can be obtained in the same way by considering the separation film 11 as one prism element and the separation film 12 as one prism element.

  In order to perform color display, the RGB light sources 1, 2, and 3 are caused to emit light sequentially in a time division manner. The liquid crystal panel 19 is driven in a time division manner in synchronization with a signal corresponding to the color light to be emitted.

  The setting of time division and the combination of colors to be emitted are arbitrary, and for example, a configuration is possible even in a cycle in which R, G, B, light and W (white) light are emitted every 1/240 s.

  W (white) light can be realized by causing the R, G, and B light sources 1, 2, and 3 to emit light simultaneously.

  In this embodiment, the light emitted from the light sources 1, 2, and 3 can be emitted from the same direction as the R, G, and B light, and can irradiate the liquid crystal panel under the same conditions. Further, since these color lights are light that is completely overlapped (white light), it is not necessary to provide an optical system for irradiating the liquid crystal panel 19 in an overlapping manner. And since the width | variety of the light source device 22 is small, a simple and small image projection apparatus can be provided.

  In the present embodiment, an image based on the liquid crystal panel 19 is projected by the projection optical system 15 onto the irradiated surface, for example, the screen surface, with the above configuration.

  The phase plate (λ / 4 plate) 5 in the embodiment may be a λ / 4 plate having different specifications for each optical path.

  FIG. 5 is a schematic diagram of a main part of the image projection apparatus according to the second embodiment of the present invention.

  The illumination optical system of this embodiment uses light source means configured to perform polarization separation and color synthesis of arbitrary two-color light with one kind of film. In FIG. 5, the same members as those shown in FIG.

  In FIG. 5, reference numeral 34 denotes a light source device. The points not described are the same as in the first embodiment.

  In the second embodiment, as compared with the first embodiment, the λ / 4 plate 23, the reflection mirror 24, and the polarization rotating element 25 that rotates the phase by 90 ° by a specific wavelength are further provided on the emission surface 13 side of the light source device 34.

  The optical characteristics of each member in the present embodiment will be described.

  The LED light source 1 that emits red light (R light) is disposed such that the optical axis 14R, which is the direction in which the light from the LED light source 1 radiates, is parallel to the direction 17 of the illumination light.

  Red random polarized light R emitted from the LED light source 1 enters the prism element 44 and enters the separation film 7.

  The separation film 7 has the optical characteristics shown in FIG. 2, and has a polarization separation function for red light.

  Therefore, the P-polarized light Rp1 of the incident light passes through the separation film 7 and travels in the direction 17 of the illumination light.

  The P-polarized light Rp1 that has passed through the separation film 7 enters the prism element 46 and enters the separation film (first polarization separation surface) 11.

  The separation film 11 has the optical characteristics shown in FIG. 4, and the red P-polarized light Rp1 is transmitted and enters the polarization rotation element 25. The polarization rotation element has a function of rotating the polarization direction by 90 ° for R light.

  Therefore, the P-polarized light Rp1 of the incident light becomes S-polarized light Rs1 by the polarization rotation element 25 and travels in the direction 17 of the illumination light.

  As a result, the light is emitted from the surface 48 that is the emission surface of the light source device 34.

  Further, the S-polarized light Rs 1 of the light incident on the prism 44 is reflected by the separation film 7, enters the prism element 45, and enters the separation film 8. The separation film 8 has the optical characteristics shown in FIG. 2, and the red S-polarized light Rs 1 is reflected and enters the λ / 4 plate 23.

  The λ / 4 plate 23 has a fast axis inclined by approximately 45 ° with respect to the vibration direction of the polarized light, and the light is converted into circularly polarized light, reflected by the reflection mirror 24, and incident on the λ / 4 plate 23 again. It is converted to P-polarized light to become P-polarized light Rp2.

  The P-polarized light Rp2 passes through the separation film 8 and travels in the direction 17 of the illumination light.

  The P-polarized light Rp <b> 2 that has passed through the separation film 8 enters the prism element 47 and enters the separation film (second polarization separation surface) 12.

  The separation film 12 has the optical characteristics shown in FIG. 4, and the red P-polarized light Rp <b> 2 is transmitted and is incident on the polarization rotation element 25. The polarization rotation element 25 has a function of rotating the polarization direction by 90 ° with respect to the R light.

  Therefore, the P-polarized light Rp2 of the incident light becomes S-polarized light Rs2 by the polarization rotation element 25 and travels in the direction 17 of the illumination light.

  As a result, the S-polarized light Rs2 is emitted from the surface 48 which is the emission surface of the light source device 34.

  Light from the G light source 2 and the B light source 3 is emitted as S-polarized light from the light source device 34 through a member having the same configuration as in the first embodiment.

  In this mode, since the light source device 34 can be further reduced with respect to the first embodiment, it is easy to further reduce the size of the image projection device.

  FIG. 6 is a schematic diagram of a main part of an image projection apparatus according to a third embodiment of the present invention.

  In this embodiment, a light source device having a polarization conversion means including a dichroic mirror and a λ / 4 plate is used as a part of the illumination device.

  In FIG. 6, the same members as those shown in FIG. Reference numeral 35 denotes a light source device. The points not described are the same as in the first embodiment.

  In the third embodiment, the G (G light) reflecting dichro 26, the λ / 4 plates 27 and 28, the R (R light) reflecting dichro 29, and the light source device 35 on the emission surface 13 side are compared with the configuration of the first embodiment. A polarization rotation element 16 that rotates the phase by 90 ° by (B light) is further provided.

  In this embodiment, the light incident on the liquid crystal panel 19 is P-polarized light.

  The optical characteristics of each member in the present embodiment will be described.

  The LED light source 1 that emits red (R light) is disposed such that the optical axis 14R, which is the direction in which the light from the LED light source 1 radiates, is parallel to the direction (outgoing direction) 17 of the illumination light.

  The red random polarized light R emitted from the LED light source 1 enters the G reflection dichroic mirror 26. The G reflection dichroic mirror 26 has the optical characteristics shown in FIG. 7, and has a transmission function for red light.

  Therefore, the R light passes through the G reflecting dichroic mirror 26, further passes through the λ / 4 plate 27, enters the prism element 46, and enters the separation film (first polarization separation surface) 7.

  The separation film 7 has the optical characteristics shown in FIG. 2, and has a polarization separation function for red light.

  Therefore, the P-polarized light Rp1 of the incident light is transmitted through the separation film 7, transmitted through the polarization rotation element 16, and travels in the direction 17 of the illumination light.

  As a result, the P-polarized light Rp1 is emitted from the surface 48 that is the emission surface of the light source device 35.

  The incident S-polarized light Rs 1 is reflected by the separation film 7, enters the prism element 47, and enters the separation film (second polarization separation surface) 8. The separation film 8 has the optical characteristics shown in FIG. 2, and the red S-polarized light Rs 1 is reflected and enters the λ / 4 plate 28.

  The λ / 4 plate 28 has a fast axis tilted by approximately 45 ° with respect to the polarization vibration direction, so that the light is converted into circularly polarized light and enters the R reflecting dichroic mirror 29. The R reflecting dichroic mirror 29 has the optical characteristics shown in FIG. 8, and has a reflecting effect on red light.

  Therefore, the R light is reflected by the R reflecting dichroic mirror 29, enters the λ / 4 plate 28 again, is converted to P polarized light, and becomes P polarized light Rp2.

  The P-polarized light Rp2 passes through the separation film 8, passes through the polarization rotation element 16, and travels in the illumination light direction 17.

  Accordingly, the P-polarized light Rp2 is emitted from the surface 48 that is the emission surface of the light source device 35.

  The LED light source 2 that emits green light (G light) is arranged so that the optical axis 14G, which is the direction in which the light from the LED light source 2 radiates, is parallel to the direction 17 of the illumination light.

  The green random polarized light G emitted from the LED light source 2 enters the R reflecting dichroic mirror 29. The R reflection dichroic mirror 29 has the optical characteristics shown in FIG. 8 and has a transmission function for green light. Therefore, the G light passes through the R reflecting dichroic mirror 29, further passes through the λ / 4 plate 28, enters the prism element 47, and enters the separation film 8.

  The separation film 8 has the optical characteristics shown in FIG. 2, and has a polarization separation action for green light.

  Therefore, the P-polarized light Gp1 of the incident light is transmitted through the separation film 8 and transmitted through the polarization rotation element 16 and travels in the illumination light direction (outgoing direction) 17.

  Accordingly, the P-polarized light Gp1 is emitted from the surface 48 that is the emission surface of the light source device 35.

  Further, the S-polarized light Gs 1 of the incident light is reflected by the separation film 8, enters the prism element 46, and enters the separation film 7. The separation film 7 has the optical characteristics shown in FIG. 2, and the green S-polarized light is reflected and enters the λ / 4 plate 27.

  The λ / 4 plate 27 has a fast axis tilted by approximately 45 ° with respect to the polarization oscillation direction, and the light is converted into circularly polarized light and is incident on the G reflection dichroic mirror 26. The G reflecting dichroic mirror 26 has the optical characteristics shown in FIG. 7, and has a reflecting action on green light.

  Therefore, the G light is reflected by the G reflecting dichroic mirror 26, is incident on the λ / 4 plate 27 again, is converted to P polarized light, and becomes P polarized light Gp2.

  The P-polarized light Gp2 passes through the separation film 7, passes through the polarization rotation element 16, and travels in the direction 17 of the illumination light.

  As a result, the P-polarized light Gp2 is emitted from the surface 48 which is the emission surface of the light source device 35.

  The LED light source (third light source) 3 that emits blue light (B light) is disposed so that the optical axis 14B, which is the direction in which the light from the LED light source 3 radiates, is orthogonal to the direction 17 of the illumination light.

  Blue random polarized light B emitted from the LED light source 3 enters the prism element 46 and enters the separation film (first polarization separation surface) 7.

  The separation film 7 has the optical characteristics shown in FIG. 2, and has a polarization separation function for blue light.

  Therefore, the first partial light of the S-polarized light (first polarized light) Bs 1 of the incident light is reflected by the separation film 7 and enters the polarization rotation element 16. The polarization rotation element 16 has a function of rotating the polarization direction by 90 ° with respect to the B light.

  Accordingly, the S-polarized light Bs1 of the incident light becomes P-polarized light Bp1 by the polarization rotation element 16 and travels in the direction 17 of the illumination light.

  As a result, the P-polarized light Bp1 is emitted from the surface 48 that is the emission surface of the light source device 35.

  Further, the blue P-polarized light (second polarized light) Bp 1 transmitted through the separation film 7 is transmitted through the separation film 7, enters the prism element 47, and enters the separation film (second polarization separation surface) 8.

  The separation film 8 has the optical characteristics shown in FIG. 2, and the blue P-polarized light Bp1 passes through the separation film 8 and enters the λ / 4 plate 5.

  The λ / 4 plate 5 has a fast axis tilted by approximately 45 ° with respect to the vibration direction of the polarized light, the light is converted into circularly polarized light, reflected by the reflection mirror 6, and incident on the λ / 4 plate 5 again. It is converted to S-polarized light and becomes S-polarized light Bs2.

  The S-polarized light Bs 2 is reflected by the separation film 8 and enters the polarization rotation element 16. The polarization rotation element has an effect of rotating the polarization direction by 90 ° with respect to the B light.

  Accordingly, the S-polarized light Bs2 of the incident light becomes P-polarized light Bp2 by the polarization rotation element 16 and travels in the direction 17 of the illumination light.

  As a result, the P-polarized light Bp2 is emitted from the surface 48 that is the emission surface of the light source device 35.

  The polarization rotation element 16 does not limit the configuration of the present embodiment, and can arbitrarily control the polarization direction of the color light emitted from the light source means 35 as necessary.

  In this mode, the number of glass members can be reduced compared to the first embodiment, and the light source device 35 can be reduced in size, so that the image projection device can be easily reduced in size and weight.

  As described above, in the first and third embodiments, the third light source 3 emits light in a direction orthogonal to or parallel to the direction in which the first and second light sources 2 and 3 emit light.

  The first light source 1 emits light in a direction orthogonal to the direction in which the third light source 3 emits light, and the second light source emits light in a direction parallel to the direction in which the first light source emits light. ing.

  As described above, in the light source devices according to the first to third embodiments, the three light sources 1, 2, 3 that emit different color lights and the polarization states of the light beams from the three light sources 1, 2, 3 are aligned and combined. It has a polarization conversion means, a λ / 4 plate, and a reflection surface. This is a light source device that emits a light beam through the polarization conversion means in the emission direction.

  As a result, when the irradiated surface is irradiated with different colored light from the same direction and an image based on the image display element arranged on the irradiated surface is projected, color unevenness is reduced in the projected image.

  The polarization conversion means includes a first prism element 46 including a first polarization separation surface (11, 7) having a polarization separation action for a predetermined color light, and a second polarization separation surface (12, 8). Including a second prism element 47.

  The first and second prism elements each have four transmission surfaces, and the first and second polarization separation surfaces are inside the first and second prisms at an angle of 45 ° with respect to the respective transmission surfaces. Has been placed.

  Of the four transmission surfaces of each of the first and second prisms 46 and 47, one transmission surface 1a and 2a constitute the exit surface of the polarization conversion means.

  The first prism element 46 and the second prism element 47 are arranged such that one transmission surface is close or bonded.

  At least one light source 3 among the three light sources 1, 2, and 3 is disposed such that the light source optical axis is orthogonal to the normal direction of the exit surface.

  The light beam from one light source 3 enters from a surface different from the transmission surface 1a of the first prism element 46, and the light in the first polarization direction is directed toward the transmission surface 1a on the first polarization separation surface. Is reflected, and light in the second polarization direction orthogonal to the first polarization direction enters the second prism element.

  The light having the second polarization direction incident on the second prism element 47 is transmitted through the λ / 4 plate through the second polarization separation surface, reflected by the reflection mirror, and again the λ / 4 plate. , And re-enters the second prism element 47 as light in the first polarization direction. Then, the light is reflected toward the transmission surface 2a of the second prism element 47 through the second polarization separation surface.

  Light from the light sources 1 and 2 other than one light source of the light source 3 is transmitted while the light from one light source 3 in the first and second prism elements 46 and 47 reaches the transmission surfaces 1a and 2a. The light is incident from a transmission surface different from the three transmission surfaces. Then, the light is emitted from the transmission surfaces 1a and 2a through the first and second polarization separation surfaces, respectively.

  The polarization conversion means in each embodiment performs polarization separation and color synthesis of arbitrary two-color light among the light from the three light sources.

  The light source device of each embodiment has the above configuration.

  This achieves a light source device that can emit light of each color from the same direction with the polarization state aligned, and can illuminate the illuminated surface uniformly with each color light, while reducing the size of the entire device. ing.

  FIG. 9 is a schematic view of a main part of a light source device according to an image projection apparatus of Embodiment 4 of the present invention.

  In this embodiment, a plane defined as a plane including the illumination light direction (outgoing direction) (Z direction) 17 and the optical axes 14R, 14G, and 14B (X direction) of the light sources 1, 2, 3 is defined as an XZ plane. A plurality (two in FIG. 9) of light source devices 22a and 22b are arranged in an axial direction (Y direction) 32 perpendicular to the XZ plane. The points not described are the same as in the first embodiment.

  In FIG. 9, 1aa, 1bb, 2aa, 2bb, 3aa, 3bb are light sources.

  In the present embodiment, a plurality of the light source devices are arranged in a direction perpendicular to the plane including the emission direction of the light beam emitted from the light source device and the light source optical axis of one light source.

  By using the light source devices 22a and 22b having the configuration of the present embodiment, the light exit surface 33 of the light beam emitted from the light source device can be changed to a light beam having an arbitrary width according to the size, aspect ratio, etc. of the liquid crystal panel. An image projection apparatus with high utilization efficiency can be provided.

  There may be any number of light source means of 2 or more.

  In this embodiment, the light source means 34 of the second embodiment and the light source means 35 of the third embodiment may be used as the light source means.

  FIG. 10 is a schematic diagram of a main part of a light source device according to an image projection apparatus of Embodiment 5 of the present invention.

  In the present embodiment, the light source device 22 of the first embodiment is positioned so as to face each other symmetrically via the reflection mirror 6. Thus, the two light source devices 22c and 22d are arranged. The points not described are the same as in the first embodiment.

  In FIG. 10, a set of light source devices 22c and 22d similar to those in the first embodiment is arranged at a position where the mirror 6 is turned right and left with the reflection mirror 6 as the center, and illumination is effectively performed.

  To provide an image projection apparatus having a high light utilization efficiency, in which a light exit surface 33 of a light beam emitted from the light source devices 22c and 22d can be a light beam having an arbitrary width according to the size, aspect ratio, etc. of the liquid crystal panel 19. Can do.

  At this time, the mirror 6 can be constituted by a single sheet with both planes as reflecting surfaces. Further, similarly to the fourth embodiment, a plurality of light source devices may be arranged along the vertical axis 32.

  Moreover, you may use the light source device 34 of Example 2, and the light source device 35 of Example 3 as a light source device.

  FIG. 11 is a schematic diagram of a main part of an illumination apparatus according to an image projection apparatus of Embodiment 6 of the present invention.

  This embodiment is characterized in that an integrator illumination unit 36 is further provided on the light emitting side of the light source device of FIG. The points not described are the same as in the first embodiment.

  In this embodiment, an integrator illumination unit 36 is disposed between the light exit surface 13 of the light source device 22 and the incident-side polarizing plate 18.

  The integrator illumination unit 36 includes a first integrator lens 37, a second integrator lens 38, and a condenser lens 39.

  Even when the luminous flux emitted from the light source device 22 has uneven brightness, the integrator illumination unit 36 can uniformly illuminate the surface of the liquid crystal panel 19. For this reason, a high-quality image projection apparatus can be provided.

  Here, the number of lens cells of the first integrator lens 37 and the second integrator lens 38 can be arbitrarily set.

FIG. 1 is an optical configuration diagram in Embodiment 1 of the present invention. Characteristics diagram of separation membrane in Example 1 of the present invention Characteristics diagram of separation membrane in Example 1 of the present invention Characteristics diagram of separation membrane in Example 1 of the present invention Optical configuration diagram in Embodiment 2 of the present invention Optical configuration diagram of Embodiment 3 of the present invention Characteristic diagram of G light reflecting dichroic mirror in Example 3 of the present invention Characteristic diagram of R light reflecting dichroic mirror in Example 3 of the present invention Configuration diagram of Embodiment 4 of the present invention Configuration diagram of Embodiment 5 of the present invention Optical configuration diagram of Embodiment 6 of the present invention Explanatory drawing of the light source part of the light source device Modification of part of light source device Part of the light source device

Explanation of symbols

1: Red light source (first light source)
2: Green light source (second light source)
3: Blue light source (third light source)
5, 23, 27, 28: λ / 4 plates 6, 24: reflection mirrors 7, 8: separation film 9, 10: separation film 11, 12: separation film 13: light emitting part 14 of light source device: optical axis of light source Direction 15: Projection optical system 16: B polarization rotating element 17: Optical axis direction 18 of light source means: Incident side polarizing plate 19: Liquid crystal panel 20: Emission side polarizing plate 22: Light source device 25 of the first embodiment: R polarized light Rotating element 26: G reflecting dichroic mirror 29: R reflecting dichroic mirror 32: Arbitrary axis 33 of the fourth embodiment: Light flux exit surface 34 of the light source: Light source device 35 of the second embodiment: Light source device of the third embodiment 36: integrator illumination optical system 37: first integrator lens 38: second integrator lens 39: condenser lens 40: light source unit 41: light emitting unit 42: collimating lenses 42 to 47: prism element

Claims (14)

A first light source emitting a first color light;
A second light source that emits second color light;
A third light source that emits third color light;
A first polarization separation surface;
A second polarization separation surface disposed non-parallel to the first polarization separation surface;
A quarter phase plate,
A reflective surface;
A light source device that emits a light beam obtained by combining the first, second, and third color lights in the emission direction,
Of the third color light, the first partial light of the first polarized light is incident on the first polarization separation surface from the third light source side, reflected by the first polarization separation surface, and guided in the emission direction. ,
The second partial light of the second polarized light whose polarization direction is orthogonal to the first polarized light of the third color light is transmitted through the first polarized light separation surface and the second polarized light separation surface, and the 1/4 position After rotating the polarization direction by 90 degrees through the phase difference plate, the reflection surface, and the quarter phase difference plate again, it is incident on the surface opposite to the third light source of the second polarization separation surface, Reflected by the second polarization separation surface and guided in the emission direction;
The first polarization separation surface receives the first partial light and the first color light and the second color light that are incident on the first polarization separation surface from a direction different from the incident direction of the light beam from the third light source. Guiding the combined luminous flux in the emission direction;
The second polarization separation surface receives the second partial light and the first color light and the second color light incident on the second polarization separation surface from a direction different from the direction of incidence of the light beam on the third light source side. A light source device characterized by guiding a combined light beam in the emission direction.   The light source device according to claim 1, wherein the first, second, and third color lights emitted from the emission direction have the same polarization state.   The light source device according to claim 1, wherein the first polarization separation surface and the second polarization separation surface are orthogonal to each other.   4. The light source device according to claim 1, wherein the third light source emits light in a direction orthogonal to or parallel to a direction in which the first and second light sources emit light. 5.   The first light source emits light in a direction orthogonal to the direction in which the third light source emits light, and the second light source emits light in a direction parallel to the direction in which the first light source emits light. The light source device according to claim 1, 2, or 3. Three light sources that emit different colored light,
A polarization conversion means for aligning and combining the polarization states of the light beams from the three light sources, a λ / 4 plate, and a reflection surface;
A light source device that emits a light beam through the polarization conversion means in an emission direction,
The polarization conversion means includes a first prism element including a first polarization separation surface having a polarization separation action for a predetermined color light, and a second prism element including a second polarization separation surface. And
Each of the first and second prism elements has four transmission surfaces, and the first and second polarization separation surfaces are 45 ° with respect to the respective transmission surfaces inside the first and second prisms. Are arranged at an angle,
Of the four transmission surfaces of each of the first and second prisms, one transmission surface 1a, 2a constitutes the exit surface of the polarization converting means,
The first prism element and the second prism element are arranged so that each one transmission surface is close to or bonded to each other,
At least one of the three light sources is disposed such that the light source optical axis is orthogonal to the normal direction of the exit surface,
The light beam from the one light source is incident from a surface different from the transmission surface 1a of the first prism element, and the light in the first polarization direction is directed toward the transmission surface 1a on the first polarization separation surface. Is reflected, and light in the second polarization direction orthogonal to the first polarization direction is incident on the second prism element,
The light having the second polarization direction incident on the second prism element is transmitted through the λ / 4 plate through the second polarization separation surface, reflected by the reflection mirror, and again the λ / 4 plate. , And re-enters the second prism element as light in the first polarization direction, and the light is directed toward the transmission surface 2a of the second prism element via the second polarization separation surface. Reflected,
The light from the light sources other than the one light source is the four transmissive surfaces of the first and second prism elements that are transmitted while the light from the one light source reaches the transmissive surfaces 1a and 2a. The light source device is configured to be incident from a transmission surface different from the three transmission surfaces and to exit from the transmission surfaces 1a and 2a through the first and second polarization separation surfaces, respectively. . Three light sources that emit different colored light,
A polarization conversion means for aligning and combining the polarization states of the light beams from the three light sources, a λ / 4 plate, and a reflection surface;
A light source device that emits a light beam through the polarization conversion means in an emission direction,
The polarization conversion means includes a first prism element including a first polarization separation surface having a polarization separation action for a predetermined color light, and a second prism element including a second polarization separation surface. And
The first prism element has transmission surfaces 1a, 1b, 1c, and 1d, and the second prism element has transmission surfaces 2a, 2b, 2c, and 2d, and the first and second polarization separation surfaces are the first and second polarization separation surfaces. , Are arranged at an angle of 45 ° with respect to the respective transmission surfaces inside the second prism,
The transmission surfaces 1a and 2a constitute the exit surface of the polarization conversion means,
The transmission surfaces 1b and 2b are arranged to face each other,
At least one of the three light sources is disposed such that the light source optical axis is orthogonal to the normal direction of the exit surface,
The light beam from the one light source is incident from the transmission surface 1c, and the light in the first polarization direction is reflected toward the transmission surface 1a at the first polarization separation surface,
Light having a second polarization direction orthogonal to the first polarization direction is transmitted through the transmission surfaces 1b and 2b and enters the second prism element, and the light having the second polarization direction incident on the second prism element. The light is transmitted through the transmission surface 2c and the λ / 4 plate through the second polarization separation surface, reflected by the reflection mirror, and again transmitted through the λ / 4 plate and the transmission surface 2c. Re-enters the second prism element as light in the first polarization direction, and the light is reflected toward the transmission surface 2a through the second polarization separation surface,
Light from a light source other than the one light source passes through the transmission surfaces 1d and 2d and is incident on the first and second prism elements, and passes through the first and second polarization separation surfaces, respectively. A light source device configured to emit light from the surfaces 1a and 2a.   The light source device according to claim 6 or 7, wherein the polarization conversion means performs polarization separation and color synthesis of arbitrary two-color light among the light from the three light sources.   The light source device according to claim 6, wherein the light source device includes a dichroic mirror.   10. A plurality of the light source devices are arranged in a direction perpendicular to a plane including a light beam emitted from the light source device and a plane including a light source optical axis of the one light source. The light source device according to claim 1.   The light source device according to claim 6, wherein two light source devices are provided symmetrically with respect to the reflection mirror.   An illuminating device that irradiates a surface to be irradiated with a light beam from the light source device according to any one of claims 1 to 11.   The lighting device according to claim 12, further comprising an integrator lighting unit on a light emitting side of the light source device.   An image projection apparatus comprising: the illumination device according to claim 12 or 13; and a projection optical system that projects the image display element illuminated with a light beam from the illumination device onto a predetermined surface.