JP2006317925A - Optical member, illumination device, and projection type video display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical member which satisfies both or at least one of the following functions; one is to prevent light re-incident upon a reflective polarizing plate from becoming linearly polarized light having undesirable polarization direction, and the other is to improve the efficiency of using returned light, to provide an illumination device comprising the optical member and to provide a projection type video display apparatus provided with the illumination device. <P>SOLUTION: A reflection member 13 and a 1/4 λ plate 14 are disposed on the light incident surface side of a rod integrator 15 and the reflective polarizing plate 16 is disposed on the light exit surface side thereof. An aperture 13a for light transmission is formed on the reflection member 13, and an LED chip of an LED 11 is located on the aperture 13a for light transmission. A mirror is formed on the back surface of the LED chip and, thereby, light leakage from the aperture 13a for light transmission is prevented. Further, as above mentioned, by disposing the 1/4 λ plate 14, the light re-incident upon a reflective polarizing plate can be prevented from becoming linearly polarized light having undesirable polarization direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical member, an illuminating device using the optical member, and a projection display apparatus using the illuminating device.

  Conventionally, a rod integrator having a light integration effect has been used to eliminate the non-uniformity of the light intensity distribution of the light source. Further, as shown in FIG. 11, a reflective polarizing plate 101 and a quarter λ plate 102 are disposed on the light exit surface side of the rod integrator 100, while a mirror 103 having a light introduction opening 103a is disposed on the light incident side. There has been proposed an illuminating device that can arrange the illuminating light to linearly polarized light in a specific direction by arranging (see Patent Document 1 and Patent Document 2).

JP 2003-98597 A JP 2005-25064 A

  However, in the above conventional technique, as shown in FIG. 10A, the quarter λ plate 102 is provided on the light exit side of the rod integrator 100. For this reason, if the circularly polarized light generated by being reflected by the reflective polarizing plate 101 and passing through the ¼λ plate 102 is reflected an odd number of times on the side surface of the rod integrator 100 before entering the ¼λ plate 102 again, 1 When the light passes through the / 4λ plate 102, it becomes undesired linearly polarized light. Therefore, there is a drawback that the polarization conversion performance is inferior. Further, as shown in FIG. 10B, the light reflected by the reflective polarizing plate 101 leaks from the light introduction opening 103a of the mirror 103, so that the utilization efficiency of the return light (recycled light) is low.

  In view of the above circumstances, the present invention suppresses the light incident on the reflective polarizing plate again from being linearly polarized light having an undesired polarization direction and / or improves the utilization efficiency of return light. The purpose is to satisfy.

  In order to solve the above problems, an optical member according to the present invention includes a rod integrator that superimposes light incident from a light incident surface and emits the light from the light exit surface, and light emitted from the light exit surface of the rod integrator. A reflective polarizing plate that transmits specific linearly polarized light while reflecting other polarized light and returning it into the rod integrator, and introducing light from the light introduction opening and from the light incident surface of the rod integrator Light introducing / reflecting means for reflecting the emitted return light by a planar or concave reflecting surface and re-entering the light incident surface, and a 1 / 4λ plate provided on the light incident surface side of the rod integrator It is characterized by comprising.

  With the above configuration, since the quarter-λ plate is provided on the light incident surface side of the rod integrator, the light incident on the reflective polarizing plate again becomes linearly polarized light with an undesired polarization direction. Can be suppressed. Specifically, in a conventional configuration (a configuration in which a 1 / 4λ plate is provided on the light exit surface side of the rod integrator), reflected linearly polarized light other than specific linearly polarized light passes through the 1 / 4λ plate. When returning light, it becomes circularly polarized light. Since the direction of rotation of circularly polarized light is reversed at the time of reflection, when it is reflected an odd number of times and then transmitted through a ¼λ plate, it becomes linearly polarized light other than specific linearly polarized light. In the case of the configuration of the present application, since the 1 / 4λ plate is provided on the light incident surface side of the rod integrator, the above situation does not occur.

  In the optical member configured as described above, an opening that matches or substantially matches the position and size of the light introduction opening may be formed in the ¼λ plate.

  The illumination device according to the present invention includes any one of the optical members described above, and a light source provided to irradiate light to the light incident surface of the rod integrator through the light introduction opening. (Hereinafter referred to as the first lighting device in this section).

  In the first lighting device, the light source may be provided in the vicinity of the light introduction opening. The light source may have a reflecting means.

  In the first illumination device, the light source includes a lamp and condensing means for condensing the light emitted from the lamp by any one of reflection, refraction, and diffraction. The light introduction opening may be located.

The illumination device according to the present invention includes a rod integrator that superimposes light incident from a light incident surface and emits the light from a light exit surface, and a specific linearly polarized light out of light emitted from the light exit surface of the rod integrator. An optical member comprising: a reflection-type polarizing plate that transmits light and reflects other polarized light; and a quarter-λ plate provided on the light exit surface side or the light incident surface side of the rod integrator;
A light source with a reflecting surface that has a reflecting surface that reflects and guides light emitted from the light emitting element to the front side;
The light emitted from the light source with the reflective surface is incident on the light incident surface of the rod integrator, and the return light emitted from the light incident surface of the rod integrator is reflected by the reflective surface of the light source with the reflective surface. And is guided again to the light incident surface of the rod integrator (hereinafter referred to as a second illumination device in this section).

  If it is said structure, since the light source with a reflective surface does not have the opening for light introduction, the utilization efficiency of a return light can be improved.

  In the second illumination device, the reflection surface of the light source may be a flat surface. Further, in the second illumination device, the reflection surface of the light source may be a concave surface.

  In these illumination devices, the light source may be a color light source that emits a predetermined color light (hereinafter referred to as a third illumination device in this section). Alternatively, in these illumination devices, the light source may be a white light source (hereinafter referred to as a fourth illumination device in this section).

  Further, the illumination device of the present invention includes a third illumination device that emits the first color light, a third illumination device that emits the second color light, a third illumination device that emits the third color light, and each illumination device. And an optical member for guiding each color light in substantially the same direction. In such a configuration, the first color light may be red, the second color light may be blue, and the third color light may be green (hereinafter referred to as a fifth illumination device in this section). The fifth illumination device may be configured so that red light, blue light, and green light are always emitted during illumination (hereinafter referred to as a sixth illumination device in this section). Alternatively, the fifth illumination device may be configured such that red light, blue light, and green light are emitted in a time-division manner during illumination (hereinafter referred to as the seventh illumination device in this section).

  According to another aspect of the present invention, there is provided a projection display apparatus comprising the above-described illumination device. For example, a third illumination device that emits red light, a third illumination device that emits blue light, a third illumination device that emits green light, and a light provided to receive color light from each illumination device There may be provided a bulb and projection means for synthesizing and projecting the respective color image lights having passed through the respective light valves.

  Or you may provide the 4th illuminating device or the 6th illuminating device, one full color light valve, and the projection means to project the image light obtained through the said full color light valve.

  Alternatively, the fourth illumination device or the sixth illumination device, a separating unit that separates the white light emitted from the illumination device into red light, green light, and blue light, and a light valve provided to receive each color light respectively. And projection means for synthesizing and projecting each color image light having passed through each light valve.

  Alternatively, the seventh illumination device, one light valve, means for supplying a video signal for each color to the light valve in synchronization with the emission timing of each color light, and image light obtained through the light valve And a projection means for projecting.

  In these configurations, the rod integrator may have the light exit surface larger than the light entrance surface.

  According to this invention, it is possible to suppress the light incident on the reflective polarizing plate from being linearly polarized light having an undesired polarization direction. Moreover, the utilization efficiency of return light can be improved.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 is a diagram showing an optical system of the projection display apparatus 4A. The projection display apparatus 4A includes three illumination devices 51R, 51G, and 51B (hereinafter, when the individual illumination devices are indicated without being specified, the symbol “51” is used). Each illumination device 51 includes an LED (light emitting diode) 11 and an optical member 12A. The illumination device 51R emits red light, the illumination device 51G emits green light, and the illumination device 51B emits blue light.

  The LED 11 includes an LED chip, an LED substrate, and a heat sink (heat sink). The LED 11 in the illumination device 51R emits red light, the LED 11 in the illumination device 51G emits green light, and the LED 11 in the illumination device 51B emits blue light.

  The optical member 12A performs light integration so that the intensity of light emitted from the LED 11 is uniform on the surface of an illumination target (for example, a liquid crystal display panel). Furthermore, it has the effect | action which aligns an emitted light with the linearly polarized light of a specific direction. The shape of the light exit surface of the optical member 12 </ b> A matches or substantially matches the shape of the liquid crystal display panel 1. The detailed structure of the optical member 12A will be described later.

  A liquid crystal drive signal (video signal) for each color is supplied from a driver (not shown) to the liquid crystal display panels 1R, 1B, and 1G. Each color image light modulated by passing through each liquid crystal display panel 1 is combined by the cross dichroic prism 2 to become full color image light. This full-color image light is enlarged and projected by the projection lens 3 and projected and displayed on a screen (not shown).

  As shown in FIG. 2A, the optical member 12 </ b> A includes a rod integrator 15, a reflective polarizing plate 16 provided on the light exit surface side of the rod integrator 15, and the rod integrator 15. The reflecting member 13 is provided on the light incident surface side, and a ¼λ plate 14 is provided between the reflecting member 13 and the light incident surface. The reflection member 13 is made of, for example, a metal mirror or a dielectric multilayer film. A light introduction opening 13a is formed in the reflection member 13, and a light emitting portion of the LED 11 is located in the light introduction opening 13a. For example, the LED chip may emit light in almost all front directions. The LED chip is disposed between the light incident surface (flat surface) via an air gap. Further, the LED chip is formed with a mirror for guiding the emitted light forward (hereinafter referred to as an LED back mirror).

  The reflection-type polarizing plate 16 is formed of a so-called wire grid, and in this embodiment, for example, S-polarized light is transmitted as desired polarized light and P-polarized light is reflected (described in the conventional section). See the official gazette). Of course, the relationship between transmission and reflection of S-polarized light and P-polarized light can be reversed. The P-polarized light reflected by the reflective polarizing plate 16 passes through the ¼λ plate 14 and becomes circularly polarized light. This circularly polarized light is reflected by the reflecting member 13 and again passes through the ¼λ plate 14 to become S-polarized light. This S-polarized light passes through the reflective polarizing plate 16 and is emitted from the rod integrator 15. The rod integrator 15 has a rectangular parallelepiped shape, but is not limited to this shape. The rod integrator 15 may have a hollow structure whose inner surface is a reflection surface, or may have a non-hollow structure made of a transparent member (for example, transparent glass).

  In each lighting device 51, a plurality of LEDs 11 may be provided. In this case, a plurality of light introduction openings 13a are formed for introduction of emitted light from each LED chip. As shown in FIG. 2B, a tapered rod integrator 15 </ b> A may be used in place of the rod integrator 15 in the optical member 12 </ b> A. The light exit surface of the rod integrator 15A is larger than the light incident surface. By using the rod integrator 15A, light having a small dispersion angle is guided to the light exit surface of the rod integrator 15A. When light having a small dispersion angle is guided to the light exit surface, the transmission efficiency of desired polarized light through the reflective polarizing plate 16 is improved. In other configurations, the rod integrator 15A can be used instead of the rod integrator 15.

  In the illumination device 51 including the optical member 12A, as described above, the P-polarized light reflected by the reflective polarizing plate 16 becomes circularly polarized light by passing through the ¼λ plate 14. This circularly polarized light is reflected by the reflecting member 13 and again passes through the ¼λ plate 14 to become S-polarized light. This S-polarized light passes through the reflective polarizing plate 16 and is emitted from the rod integrator 15. That is, it is possible to suppress the light incident on the reflective polarizing plate 16 from being linearly polarized light having an undesired polarization direction. Further, the LED 11 is provided so as to block the light introducing opening 13a, and the return light is reflected by the LED rear mirror of the LED 11, so that the utilization efficiency of the return light can be improved.

  FIG. 3 is an explanatory diagram showing an illumination device including the LED 11 and the optical member 12B. The optical member 12B includes a rod integrator 15, and a reflecting member 13A and a 1 / 4λ plate 14A provided on the light incident surface side of the rod integrator 15. The reflecting member 13A and the ¼λ plate 14A are separated from the light incident surface of the rod integrator 15 and have a concave shape (a concave curved surface shape or a concave polyhedral surface shape). In this embodiment, the ¼λ plate 14A is formed in a half region (corresponding to a half circumference) of the reflecting member 13A. A light introduction opening 13Aa is formed in the reflection member 13A. The light emitting portion of the LED 11 is located in the light introduction opening 13Aa. As the reflection member 13A, for example, a parabolic reflector can be used. The quarter λ plate 14A may be attached to the reflection surface of the parabolic reflector. Instead of the concave 1 / 4λ plate 14 </ b> A, a flat plate-shaped 1 / 4λ plate 14 may be disposed on the light incident surface of the rod integrator 15.

  FIG. 4 is an explanatory view showing the projection display apparatus 4B. The illumination device of the projection display apparatus 4B includes a light source 10 and the optical member 12A. The light source 10 includes a lamp such as an ultra-high pressure mercury lamp, a metal halide lamp, and a xenon lamp, and an elliptical reflector that condenses the irradiation light. In addition, you may provide the parabolic reflector which collimates the said irradiation light without using the said elliptical reflector, and the lens which condenses the parallel light from this parabolic reflector. The condensing position of the light emitted from the light source 10 is a position where the light introduction opening 13a is formed. A full-color transmissive liquid crystal display panel 1F and a projection lens 3 are provided on the light emitting side of the optical member 12A. Even in such a configuration, it is possible to prevent light incident on the reflective polarizing plate 16 from being linearly polarized light having an undesired polarization direction.

  FIG. 5 is an explanatory view showing the projection display apparatus 4C. The illumination device of the projection display apparatus 4C includes a light source 10 and an optical member 12C. The optical member 12C has substantially the same structure as the optical member 12A, but differs from the optical member 12A in that an opening 14a is formed in the ¼λ plate 14. The formation position of the opening 14a coincides with the formation position of the light introduction opening 13a. When the light from the light source 10 is introduced into the light introduction opening 13a from an oblique direction, the opening 14a may be formed slightly shifted from the light introduction opening 13a. When a plurality of light sources 10 are provided and light from each light source 10 is introduced into the light introduction opening 13a from an oblique direction, the opening 14a may be somewhat larger than the light introduction opening 13a. . On the light emitting side of the optical member 12C, a full-color transmissive liquid crystal display panel 1F and a projection lens 3 are provided.

  In the configuration shown in FIGS. 4 and 5, an LED that emits white light may be provided instead of the light source 10. This LED is disposed in the light introduction opening 13a. Moreover, when this LED has an LED rear-view mirror, the utilization efficiency of return light is improved.

  In the configuration shown in FIG. 3, the light source 10 may be provided instead of the LED 11. In the case of this configuration, the light from the light source 10 is collected toward the light introduction opening 13Aa, and then spreads and guided to the light incident surface of the rod integrator 15. In this configuration, a flat quarter λ plate 14 may be disposed on the light incident surface. In this case, the light that has spread through the light introduction opening 13Aa is applied to the flat quarter λ plate 14. As a result, the adverse effect of the light from the light source 10 on the ¼λ plate 14 is almost eliminated.

  The lighting device shown in FIGS. 6 to 8 shows a configuration example that does not include the reflecting member 13 (13A) with the light introduction opening. In these configurations, the reflection surface of the light source itself is used for reflection of the return light, and the use efficiency of the return light is improved by not having the light introduction opening. Regarding polarization conversion, it is desirable to adopt a structure that suppresses light incident on the reflective polarizing plate 16 from being linearly polarized light having an undesired polarization direction. However, such a structure is not necessarily employed. Also good.

  FIG. 6A is an explanatory view showing an illumination device including a light source 10A and an optical member 12D. The light source 10A has a lamp and a parabolic reflector 13B, and a 1 / 4λ plate 14B is pasted on the reflecting surface of the parabolic reflector 13B. The light emitting element of the light source 10A is not limited to a lamp but may be a solid light emitting element. The parabolic reflector 13B and the ¼λ plate 14B do not have a light introduction opening. The optical member 12 </ b> D includes a reflective polarizing plate 16 on the light exit surface of the rod integrator 15. The light source 10 </ b> A is disposed with its light exit opening facing the light incident surface of the rod integrator 15. The shape of the light exit opening may coincide with or substantially coincide with the shape of the light incident surface of the rod integrator 15. As shown in FIG. 6B, an optical member 12E in which a flat quarter-λ plate 14 is arranged on the light incident surface of the rod integrator 15 may be used instead of the quarter-λ plate 14A. . In addition, as shown in FIG. 6C, an optical member 12F in which a flat quarter-λ plate 14 is disposed between the reflective polarizing plate 16 and the light exit surface of the rod integrator 15 may be used.

  Fig.7 (a) is explanatory drawing which showed the illuminating device which consists of LED11 and the optical member 12E. The size of the light emitting surface of the LED 11 (the size of the LED rear mirror) is the same as or substantially the same as the size of the light incident surface of the rod integrator 15 (for example, 90% or more). All or most is covered with an LED rear-view mirror. When the light incident surface of the rod integrator 15 is square, the shape of the light emitting surface of the LED 11 is preferably square.

  FIG.7 (b) is explanatory drawing which showed the illuminating device which consists of LED11 and the optical member 12F. The size of the light emitting surface of the LED 11 (the size of the LED rear mirror) is the same as or substantially the same as the size of the light incident surface of the rod integrator 15 (for example, 90% or more). All or most is covered with an LED rear-view mirror. When the light incident surface of the rod integrator 15 is square, the shape of the light emitting surface of the LED 11 is preferably square.

  FIG. 8A is an explanatory diagram showing an illumination device including two LEDs 11 and 11 and an optical member 12G. The optical member 12G includes a tapered rod integrator 15A having a light exit surface larger than the light incident surface. A reflective polarizing plate 16 is provided on the light exit surface of the rod integrator 15A. The two LEDs 11 and 11 have their principal ray axes orthogonal to the central axis of the rod integrator 15A and are arranged in the vicinity of the light incident surface of the rod integrator 15A. A 1 / 4λ plate 14C is disposed on the light emitting side of each LED 11, and the return light emitted from the light incident surface of the rod integrator 15A is reflected by the mirror 17 and transmitted through the 1 / 4λ plate 14C. Then, the light is reflected by the LED rear surface mirror and again transmitted through the ¼λ plate 14C, then reflected by the mirror 17 and incident on the light incident surface of the rod integrator 15A.

  FIG. 8B is an explanatory view showing an illumination device including two LEDs 11 and 11 and an optical member 12H. The optical member 12H includes a tapered rod integrator 15A having a light exit surface larger than the light incident surface. A reflective polarizing plate 16 is provided on the light exit surface of the rod integrator 15A. The two LEDs 11 and 11 have their principal ray axes orthogonal to the central axis of the rod integrator 15A and are arranged in the vicinity of the light incident surface of the rod integrator 15A. The light emitted from the two LEDs 11 and 11 is reflected by the mirrors 17 and 17, respectively, and guided to the light incident surface of the rod integrator 15A. The return light emitted from the light incident surface of the rod integrator 15A is reflected in the order of the mirror 17, the LED rear surface mirror of the LED 11, and the mirror 17, and enters the light incident surface of the rod integrator 15A. 14 is reached.

  In the configurations shown in FIGS. 8A and 8B, a configuration including more LEDs can be employed.

  Further, for example, the illumination devices (51R, 51G, 51B) that emit the respective color lights shown in FIG. 1 are used, and the color light (red light, blue light, and green light) from these illumination devices is cross-dichroic prism or cross-dichroic mirror. It is possible to adopt an illumination device that is guided in the same direction. Of course, other illumination devices or optical members of the present invention can be used for each color. A liquid crystal display panel used in a projection display apparatus using an illumination device that guides each color light in the same direction has a structure with an RGB color filter or a structure without an RGB color filter. When a liquid crystal display panel having a structure including an RGB color filter is used, all the lighting devices are simultaneously turned on to guide white light to the liquid crystal display panel. When a liquid crystal display panel having a structure without the RGB color filter is used, each lighting device is sequentially turned on for a predetermined time in a time-sharing manner, and images of each color are displayed on the liquid crystal display panel in synchronization with the lighting timing of the predetermined time. Supply signal.

  FIG. 9 is an explanatory view showing a three-plate projection display apparatus 4D. As an example, the projection display apparatus 4D includes the optical member 12C and the light source 10 shown in FIG. Of course, instead of the optical member 12C and the light source 10, another illumination device or optical member of the present invention can be used. The white light emitted from the light source 10 enters the optical member 12C, the polarization direction is aligned, and the light is integrated and emitted from the optical member 12C. White light emitted from the optical member 12 </ b> C is guided to the first dichroic mirror 68. The first dichroic mirror 68 transmits light in the red wavelength band and reflects light in the cyan (green + blue) wavelength band. The light in the red wavelength band that has passed through the first dichroic mirror 68 is reflected by the reflection mirror 69 to change the optical path. The red light reflected by the reflection mirror 69 passes through a condenser lens 70 and is transmitted through a transmissive liquid crystal display panel 81 for red light, thereby being optically modulated. On the other hand, the light in the cyan wavelength band reflected by the first dichroic mirror 68 is guided to the second dichroic mirror 71.

  The second dichroic mirror 71 transmits light in the blue wavelength band and reflects light in the green wavelength band. The light in the green wavelength band reflected by the second dichroic mirror 71 is guided to the transmissive liquid crystal display panel 82 for green light through the condenser lens 72, and is modulated by being transmitted therethrough. The light in the blue wavelength band transmitted through the second dichroic mirror 71 is guided to the transmissive liquid crystal display panel 83 for blue light through the reflection mirrors 74 and 76, the relay lenses 73 and 75, and the condenser lens 77. The light is modulated by passing through this.

  Each of the liquid crystal display panels 81, 82, 83 includes a panel portion 81b formed by sealing liquid crystal between an incident side polarizing plate 81a, 82a, 83a and a pair of glass substrates (with pixel electrodes and alignment films formed). 82b, 83b and output side polarizing plates 81c, 82c, 83c. The modulated light (each color video light) modulated by passing through the liquid crystal display panels 81, 82, 83 is synthesized by the cross dichroic prism 78 to become color video light. This color image light is enlarged and projected by the projection lens 79, and is projected and displayed on the screen.

  In the above description, the projection-type image display device (rear type or front type) uses a transmissive liquid crystal panel. However, the present invention is not limited to this, and a reflective liquid crystal panel may be used. Instead of this, a display panel of a type that individually drives a large number of micromirrors serving as pixels may be used.

  In the illumination device described above, a curved curved mirror for projection may be provided instead of the projection lens. Further, the solid light emitting element is not limited to an LED, and an organic or inorganic EL (electroluminescence) may be used.

It is explanatory drawing which showed the three-plate-type projection type video display apparatus provided with the optical member (illuminating device) of this invention. 1A is an explanatory view showing the optical member (illuminating device) of FIG. 1, and FIG. 1B is an explanatory view showing a configuration in which a taper rod is used as a rod in FIG. 1A. It is explanatory drawing which showed the other optical member (illuminating device) of this invention. It is explanatory drawing which showed the single plate type projection type video display apparatus provided with the other optical member (illuminating device) of this invention. It is explanatory drawing which showed the single plate type projection type video display apparatus provided with the other optical member (illuminating device) of this invention. (A), (b), and (c) are explanatory views of another optical member (illumination device) of the present invention. FIGS. 9A and 9B are explanatory views of another optical member (illuminating device) of the present invention. FIGS. 9A and 9B are explanatory views of another optical member (illuminating device) of the present invention. It is explanatory drawing which showed the three-plate-type projection type video display apparatus provided with the optical member (illuminating device) of this invention. FIGS. 9A and 9B are explanatory diagrams for explaining the drawbacks of the prior art. It is the perspective view which showed the rod integrator with the conventional polarization conversion function.

Explanation of symbols

2 Cross dichroic prism 4A, 4B, 4C, 4D Projection type image display device 11 LED
12A, 12B, 12C, 12D, 12E, 12F, 12G Optical member 13, 13A, 13B Reflective member 14, 14A, 14B 1 / 4λ plate 15 Rod integrator 51 Illumination device

Claims (9)

A rod integrator that superimposes light incident from the light incident surface and emits the light from the light exit surface, and transmits specific linearly polarized light out of the light emitted from the light exit surface of the rod integrator, while the other polarized light A reflective polarizing plate that reflects the light back into the rod integrator, and introduces light from the light introduction opening and returns light emitted from the light incident surface of the rod integrator on a planar or concave reflective surface. An optical member comprising: light introducing / reflecting means that reflects and re-enters the light incident surface; and a 1 / 4λ plate provided on the light incident surface side of the rod integrator. 2. The optical member according to claim 1, wherein the quarter-λ plate is formed with an opening that coincides with or substantially coincides with a position and a size of the light introduction opening. 3. The optical member according to claim 1, wherein the rod integrator has a light exit surface larger than the light entrance surface. 4. An optical member according to any one of claims 1 to 3, and a light source provided so as to irradiate light onto a light incident surface of the rod integrator through the light introduction opening. A lighting device characterized by the above. 5. The illumination device according to claim 4, wherein the light source is provided in the vicinity of the light introduction opening. 6. The illuminating device according to claim 4, wherein the light source has a reflecting means. 5. The illumination device according to claim 4, wherein the light source includes a lamp and condensing means for collecting light emitted from the lamp by reflection, refraction, or diffraction, and collects the light emitted from the light source. An illumination device, wherein the light introduction opening is located at a light spot. A rod integrator that superimposes light incident from the light incident surface and emits the light from the light exit surface, and transmits specific linearly polarized light out of the light emitted from the light exit surface of the rod integrator and transmits other polarized light. An optical member comprising: a reflective polarizing plate that reflects; and a 1 / 4λ plate provided on the light exit surface side or the light incident surface side of the rod integrator;
A light source with a reflecting surface that has a reflecting surface that reflects and guides light emitted from the light emitting element to the front side;
The light emitted from the light source with the reflective surface is incident on the light incident surface of the rod integrator, and the return light emitted from the light incident surface of the rod integrator is reflected by the reflective surface of the light source with the reflective surface. And being guided again to the light incident surface of the rod integrator. A projection-type image display device comprising the illumination device according to claim 4.

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