JP3669371B2 - Illumination device for image display device - Google Patents

Description

  The present invention relates to a projection-type image display device including a modulation element illuminated by an illumination device and a projection lens that forms an image of the modulation element.

  2. Description of the Related Art Conventionally, there has been proposed a projection type image display device that includes an illumination device, a modulation element illuminated by the illumination device, and a projection lens that forms an image of the modulation element. Such an image display device has been put to practical use as a relatively large image display device using a discharge lamp as a light source of an illumination device and using liquid crystal as a modulation element.

  In such an image display device, the cost of the device can be reduced by adopting a structure in which a color filter is arranged in each pixel of one modulation element and a so-called sequential color display method for performing color display in a time division manner. However, there is a problem that light utilization efficiency is low and power consumption is large.

  The reason why the light use efficiency is low is that the modulation element is a non-light-emitting element that modulates the polarization state of incident light, so a means for separating the light beam emitted from the light source by the polarization component and then synthesizing it is necessary. Unlike the display device, the light source emits light even in black display, and there is a loss corresponding to the light use efficiency determined by the aperture ratio of the modulation element.

  In the conventional image display device, the light use efficiency is improved in the optical elements and the like constituting the image display device as follows.

[Separation and synthesis of polarization components]
As shown in FIG. 45, a polarization conversion element that separates and synthesizes a light beam emitted from the light source of the illuminating device in accordance with the polarization component is P between the light source 101 and the modulation element 102, as shown in FIG. A -S conversion element 103 is known. As shown in FIG. 46, the PS conversion element 103 includes a plate glass 105 having a polarization separation film 104 formed of a multilayer film made of an inorganic material formed on the surface and a plate glass 107 having a reflection surface 106 formed on the surface. The glass blocks 108 are alternately cut to form a plate along a cutting surface 109 inclined with respect to the bonding surface.

  When a light beam mixed with P-polarized light and S-polarized light is incident on the PS conversion element 103, the P-polarized light and the S-polarized light are separated in the polarization separation film. Each layer constituting the S conversion element is separated and emitted. A light beam having only one of the P-polarized light and the S-polarized light component is provided on the light exit side by arranging the λ / 2 plate 110 at the light output corresponding to the S-polarized light or the P-polarized light. Is obtained.

  By using such a PS conversion element 103 and the λ / 2 plate 110 as a polarization separation device, it is possible to improve light use efficiency as an illumination device that illuminates a modulation element that modulates a polarization component of incident light. .

  In this illuminating device, the light beam emitted from the light source 101 is reflected by the parabolic mirror 111 and enters the PS conversion element 103 via the pair of fly-eye lenses 112 and 113. Then, the light reaches the modulation element 102 through the λ / 2 plate 110 and the condenser lens 114.

[Reflective polarizing plate]
Conventionally used polarizing plates transmit one polarization component and absorb the other polarization component. As a polarizing plate, there is known a “reflective polarizing plate” that transmits one polarization component and reflects the other polarization component without absorbing it. When such a “reflective polarizing plate” is used as a polarization conversion element, the other polarization component can be used by reflecting it again, and the light utilization efficiency can be improved.

[Linear polarizing plate using birefringent multilayer film]
A linearly polarizing plate using a birefringent multilayer film is made by laminating and stretching two types of polymer films each having refractive index anisotropy and different refractive indexes. That is, the two kinds of laminated polymer films have the same refractive index with respect to one polarization axis direction, and the refractive indexes with respect to the other polarization axis direction do not match each other. By adjusting the refractive indexes different from each other in this way, it is possible to configure a “reflective polarizing plate” that transmits polarized light with one polarization axis direction and reflects polarized light with the other polarization axis direction orthogonal thereto. .

  As such a “reflective polarizing plate”, there are those sold by “3M Company” under the trade name “DBEF” and the trade name “HMF”.

[Circular polarizing plate using cholesteric liquid crystal]
A circularly polarizing plate using selective reflection of cholesteric liquid crystal is selectively reflected by changing the pitch of cholesteric by 100 nm or more as described in, for example, JP-A-6-281814 (Patent Document 1). It is possible to make the wavelength range of the entire visible range. By using such a cholesteric circularly polarizing plate, it is possible to produce a circularly polarizing plate having no wavelength dependency.

  A circularly polarizing plate using a cholesteric liquid crystal and a polarization conversion element using the same are disclosed in, for example, Japanese Patent No. 2509372. This element has the characteristics of circularly polarized light, that is, the phase changes by 180 ° by one reflection, so that clockwise circularly polarized light changes to counterclockwise circularly polarized light and counterclockwise circularly polarized light changes to clockwise circularly polarized light. It is something that uses that. As shown in FIG. 47, by combining a cholesteric liquid crystal 115 with a reflecting mirror 111, a polarization separation / synthesis device can be configured. In the polarization separating / synthesizing apparatus using linearly polarized light as described above, the λ / 2 plate is required. However, in the case of circularly polarized light, the λ / 2 plate is not required.

  That is, the light beam emitted from the light source 101 enters the cholesteric liquid crystal 115 through the condenser lens 116, is reflected by the reflecting mirror 111, and enters the cholesteric liquid crystal 115 through the condenser lens 116. At this time, circularly polarized light in one direction passes through the cholesteric liquid crystal 115, but circularly polarized light in the other direction is reflected by the cholesteric liquid crystal 115. The circularly polarized light in the other direction reflected by the cholesteric liquid crystal 115 in this way is reflected by the reflecting mirror 111 to become unidirectional circularly polarized light, and is incident on the cholesteric liquid crystal 115 again. To Penetrate.

JP-A-6-281814

  Incidentally, the illumination device used in the image display device as described above has the following problems.

[Manufacturing process]
The lighting device as described above has a complicated manufacturing process, is complicated to manufacture, and is expensive.

[Problems of circularly polarizing plates using cholesteric liquid crystals]
The circularly polarizing plate described in Patent Document 1 described above has no wavelength dependency, but it cannot be said to have sufficient polarization separation characteristics. Therefore, in order to obtain the contrast necessary for the image display device, it is necessary to use it together with an absorption-type polarizing plate (polarizing plate that absorbs the other polarized light). Therefore, it has been difficult to improve the light utilization efficiency.

[Problems of polarized light separator using cholesteric liquid crystal circular polarizer]
The illumination device shown in FIG. 47 described in Japanese Patent No. 2509372 and JP-A-6-281814 described above is considered in the shape of a reflector (reflector) of a discharge lamp that is actually used as a light source, or In the case where it is assumed that the modulation element is illuminated, the expected effect is not always obtained.

  That is, as shown in FIG. 48, since the shape of the reflector 111 of the actual discharge lamp is a paraboloidal shape or a spheroid shape, the light source 101 is formed by the polarization separation element made of the cholesteric liquid crystal 115. The light beam reflected to the side is reflected by the reflecting plate 111 twice. If the phase change caused by one reflection on the reflector 111 is 180 ° and is reflected twice, the phase will not change.

  Furthermore, there is a difference in the reflectance of P-polarized light and S-polarized light on the reflecting plate 111, and phase change and scattering are caused by passing through the glass tube of the discharge lamp as the light source 101, so that the effect of polarization conversion is reduced. End up. In addition, when the reflector is a parabolic mirror, the light beam emitted from the focal position returns to the focal position when reflected by the reflective polarizing plate, but the light beam emitted from a point other than the focal position is reflected polarized light. The light reflected by the plate does not necessarily return to the light emitting point.

  As shown in FIG. 49, when an ellipsoidal mirror is used as the reflecting mirror 111, depending on the position of the cholesteric liquid crystal 115, the reflected light from the cholesteric liquid crystal 115 does not return to the light emitting point of the light source 101. The angle distribution is widened after being absorbed by the electrode of the discharge lamp or reflected by the reflecting mirror 111. The widening of the angular distribution increases the etendue of the light source, which causes a reduction in the use efficiency of the illumination light.

  As described above, the polarization conversion element in the conventional illumination device has problems in terms of light utilization efficiency and manufacturing cost, and sufficient efficiency as a means for returning light to the light source cannot be obtained.

  Therefore, the present invention is proposed in view of the above-described circumstances, and an image display using an illuminating device with improved use efficiency of illuminating light without incurring a complicated configuration or complicated manufacturing. The device is to be provided.

  In order to solve the above-mentioned problems, an image display device according to the present invention includes an illumination device having a light source, a modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image, and transmits or reflects the illumination light. A projection lens that forms an image of the modulation element; and a first reflection element that reflects unnecessary light that does not illuminate the modulation element, out of the light flux emitted from the illumination device, to the light source side. Is provided with a reflecting mirror that has a reflecting surface that reflects light from the light emitting point as a parabolic surface, and a protective glass provided on the opening end side of the reflecting mirror, on one of the front and back surfaces of the protective glass. A second reflecting element that reflects unnecessary light reflected by the first reflecting element is provided.

  An image display device according to the present invention includes an illumination device having a light source, a modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image, and transmits or reflects the image. A projection lens that forms an image; and a first reflecting element that reflects unnecessary light that does not illuminate the modulation element out of the light flux emitted from the illuminating device to the light source side. A reflection mirror having a spheroid surface as a reflection surface for reflecting light; and a protective glass provided on an opening end side of the reflection mirror, wherein the first reflection is provided on one of the front and back surfaces of the protection glass. A second reflecting element that reflects unnecessary light reflected by the element is provided.

  Further, an image display device according to the present invention includes an illumination device having a light source, a modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image, and transmits or reflects the image. A projection lens that forms an image; and a first reflective element that includes a reflection-type polarizing plate that reflects unnecessary light that does not illuminate the modulation element out of the luminous flux emitted from the illumination device, to the light source side, and the light source Is provided with a reflecting mirror that has a reflecting surface that reflects light from the light emitting point as a parabolic surface, and a protective glass provided on the opening end side of the reflecting mirror, on one of the front and back surfaces of the protective glass. A second reflecting element that reflects unnecessary light reflected by the first reflecting element is provided, and is disposed between the second reflecting element and the first reflecting element to be a quarter wavelength. A plate is provided.

  Further, an image display device according to the present invention includes an illumination device having a light source, a modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image, and transmits or reflects the image. A projection lens that forms an image; and a first reflective element that includes a reflection-type polarizing plate that reflects unnecessary light that does not illuminate the modulation element out of the luminous flux emitted from the illumination device, to the light source side, and the light source Is provided with a reflecting mirror that has a reflecting surface that reflects light from the light emitting point as a spheroidal surface, and a protective glass provided on the opening end side of the reflecting mirror, on either the front or back surface of the protective glass A second reflecting element for reflecting unnecessary light reflected by the first reflecting element is provided, and a relay lens and a field lens are provided between the quarter-wave plate and the first reflecting element. Yes.

  The image display apparatus according to the present invention can improve the use efficiency of illumination light, and can display a bright and high-quality image while suppressing the increase in size of the light source.

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

[Outline of general lighting equipment]
Prior to the description of the present invention, a general lighting device in an image display device using a modulation element that modulates the polarization state will be described. As shown in FIG. 1, the illumination device includes a light source 1, an integrator element 2, a polarization conversion element 3, and a condenser lens group 4. The illumination light emitted from the illumination device enters the modulation element 5. In addition, a color separation element may be disposed between the polarization conversion element 3 and the modulation element 5 in order to correspond to a modulation element corresponding to the display of the three primary colors (R, G, B).

  The integrator element 2 averages the unevenness of the light intensity distribution in the light beam emitted from the light source 1. The polarization conversion element 3 is an element having a function of separating and synthesizing a light beam emitted from the light source 1 according to a polarization component. The condenser lens group 4 is an element for efficiently causing the light beam emitted from the integrator element 3 to enter the modulation element 5. The condenser lens group 4 is a lens that forms an image of the integrator element 2 on the modulation element 5.

[Outline of lighting device]
An illumination device according to the present invention modulates a first reflecting element that reflects unwanted light that does not illuminate a modulation element among light beams emitted from a light source to the light source side, and a light beam reflected by the first reflecting element. And a second reflecting element that reflects toward the element side. With these reflecting elements, unnecessary light can be reused as illumination light, and the display image can be brightened without increasing the light emission intensity of the light source itself.

  Such an illuminating device in which unnecessary light can be reused as illuminating light is referred to as a “recyclable illuminating device” in the following description. In the present invention, an image display device as shown below can be configured by using this “recycle type lighting device”.

(1) Image display device provided with polarization type recycling illumination device (2) Image display device provided with illumination device that effectively improves aperture ratio of modulation element (3) High-efficiency single plate color image display device (4) High-efficiency sequential color image display device (5) Image display device with improved peak luminance Each lighting device used in these image devices will be described later.

[Basic type of recyclable lighting equipment]
As shown in FIG. 2, the recycle type illumination device includes an illumination optical system including a light source 1, an integrator element 2, a polarization conversion element (not shown), and a condenser lens group 4, and further includes a first reflection element 6. ing. Here, the light source 1 uses a discharge lamp provided with a parabolic mirror 7 which is a rotating parabolic reflecting mirror. The light emitting point of the discharge lamp as the light emitting unit is located at the focal point of the parabolic mirror 7. The integrator element 2 is shown as a fly-eye integrator having a first fly-eye lens surface 8 and a second fly-eye lens surface 9. A polarization conversion element (not shown) is disposed after the integrator element 2. The condenser lens group 4 is shown as comprising a condenser lens 10 and a field lens 11. Here, the first reflecting element 6 is shown as a plane mirror perpendicular to the optical axis.

  In the following description, the light beam reaching the first reflecting element 6 from the light source 1 is referred to as primary light, and the light beam after being reflected by the first reflecting element 6 is referred to as recycled light. In FIG. 2, a representative light beam of the primary light is indicated by a solid line, and recycled light corresponding to the primary light is indicated by a broken line.

  That is, the primary light emitted from the light emitting point of the discharge lamp located at the focal point of the parabolic mirror 7 is reflected by the parabolic mirror 7 to become a parallel light flux, and the first fly eye lens surface of the fly eye integrator. 8 is incident perpendicularly. The primary light is converged for each divided element of the first fly-eye lens surface 8 and condensed on each divided element of the second fly-eye lens surface 9. That is, the light source image of the primary light is formed on each divided element of the second fly-eye lens surface 9. The primary light passes through the second fly-eye lens surface 9 and the condenser lens group 4 and reaches the first reflecting element 6. This illumination optical system is a telecentric optical system in which the principal ray is parallel to the optical axis at the position of the first reflecting element 6.

  Here, each divided element of the first fly-eye lens surface 8 and the first reflecting element 6 have a conjugate relationship. The second fly's eye lens surface 9 and the light emitting point of the light source 1 are in a conjugate relationship, and the corresponding dividing element of the first fly's eye lens surface 8 has a diaphragm action.

  Then, the recycled light reflected by the first reflecting element 6 returns to the fly eye integrator element 2. Of this recycled light, the light beam that has passed through the range where the primary light has passed through the second fly-eye lens surface 9 and has passed through the corresponding first fly-eye lens surface 8 is coupled to the light emitting point. Image.

  Actually, since the size of the parabolic mirror 7 is finite and the glass bulb forming the light source 1 is a shielding object, there exists recycled light that is shielded in the process of returning to the light emitting point.

[Lighting equipment that improves recycling efficiency]
In the illuminating device used for the image display device according to the present invention, as shown in FIG. 3, the first reflecting element 6 is inclined with respect to the optical axis, and the reflecting plate 14 serving as the second reflecting element is provided. This improves the recycling efficiency of illumination light. The illumination device has an illumination optical system including a light source 1, an integrator element 2, a polarization conversion element (not shown), and a condenser lens group 4, and further includes a first reflection element 6. Here, the light source 1 is shown as a discharge lamp provided with an elliptical mirror 16 that is a reflecting mirror of a spheroidal surface, and the light emitting point is located on the first focal point of the elliptical mirror 16. The condenser lens group 4 includes two lenses, a condenser lens (relay lens) 10 and a field lens 11.

  At the second focal position of the elliptical mirror 16, a reflecting plate 14 that also serves as a stop is disposed. The reflecting plate 14 is made of a material having high reflectivity, and has an opening pattern corresponding to a light beam emitted from the second fly-eye lens surface 9 of the integrator element 2 for each divided element.

  The image side focal length of the condenser lens 10 is set to be in the vicinity of the field lens 11. This illumination optical system is a telecentric optical system in which the principal ray is parallel to the optical axis at the position of the first reflecting element 6. In this illumination optical system, the recycled light reflected by the first reflecting element 6 returns to a position deviated from the opening pattern of the reflecting plate 14 because the first reflecting element 6 is inclined with respect to the optical axis. The reflection plate 14 reflects the light. The recycled light reflected by the reflecting plate 14 returns to the first reflecting element 6 again. In FIG. 3, a representative light beam of the primary light is indicated by a solid line, and a recycling path is indicated by a broken line.

  As shown in FIG. 4, this illuminating device may be configured by shifting the optical axis of the optical system after the condenser lens 10 in parallel by an appropriate amount. Here, the appropriate amount for shifting the optical axis is about 1/4 of the element division pitch in the fly-eye integrator 2. Also in FIG. 4, a representative light beam of the primary light is indicated by a solid line, and a recycling path is indicated by a broken line.

  In the illumination devices shown in FIGS. 3 and 4, the opening diameter of the reflector 14 is generally determined by the etendue of the object to be illuminated, but is determined in consideration of the aspect ratio of the object to be illuminated and the recycling efficiency.

  The positions of the second flyer eye lens surface 9 and the reflecting plate 14 are substantially conjugate positions. That is, the recycled light reflected by the first reflecting element 6 forms an illuminance distribution different from the illuminance distribution of the primary light on the second fly-eye lens surface 9, and the illuminance pattern of each element is the reflector 14. It is superimposed on the position of. For example, if each element shape of the second fly-eye lens surface 9 is the same rectangular shape, the illuminance pattern on the reflection plate 14 of the recycled light is a rectangular shape in which the illuminance at the central opening corresponding to each element shape is low. It becomes.

  Further, the pattern of the reflected light from the first reflecting element 6 forms a similar pattern in each divided element of the first fly-eye lens surface 8. When the first fly's eye lens surface 8 and the image side focal position of the condenser lens group 4 coincide with each other, when the first fly's eye lens surface 8 is reached again, it returns to a symmetrical position with respect to the optical axis. In the case where the configuration of the first fly-eye lens surface 8 is a symmetrical layout with respect to the optical axis, a symmetrical pattern of the reflection pattern is formed on each divided element of the first fly-eye lens surface 8, and again The first reflective element 6 is illuminated without making the illuminance uniform. For the purpose of making the illuminance uniform, it is better to leave a gap between the field lens 11 and the first fly-eye lens surface 8. Since the light rays other than the principal ray do not have a symmetrical relationship at the position of the first fly-eye lens surface 8, the illuminance of the recycled light can be made uniform.

  As shown in FIG. 5, the illuminating device according to the present invention is disposed near the light source 1 having the elliptical mirror 16, the relay lens 20 disposed on the second focal point of the elliptical mirror 16, and the relay lens 20. When the reflector 14, the field lens 21, the reflective polarizing plate 19, the fly eye integrator 2, the condenser lens 10, the field lens 11 and the first reflective element 6 are sequentially arranged, the optical system after the condenser lens 10 is arranged. These optical axes can be shifted in parallel.

  The reflecting plate 14 has an opening at the center and functions as a diaphragm for the relay lens 20.

  In this illumination device, the recycled light reflected by the reflective polarizing plate 19 returns to the light emitting point of the light source 1 through the field lens 21, the relay lens 20, and the elliptical mirror 16. The recycled light reflected by the first reflecting element 6 is reflected by the reflecting plate 14 and returns to the first reflecting element 6 again. Also in FIG. 5, a representative light beam of the primary light is indicated by a solid line, and a recycling path is indicated by a broken line.

[About the first reflective element]
The first reflective element does not necessarily have to be added with a special element as the first reflective element. That is, an element that originally exists to reflect unnecessary light for another purpose can be used as the first reflecting element. Examples of the element that can be the first reflective element include a reflective polarizing plate, a polarizing beam splitter, a light shielding layer, a reflective layer of a reflective modulation element, and a reflective color filter. Specific arrangement will be described later.

[Requirements for improving recycling efficiency]
The requirements for improving the recycling efficiency of the illumination light include the following four requirements.
(1) The relationship between the first reflective element and the integrator is an optical conjugate point.
(2) The surface reflection of the members constituting the lighting device should be as small as possible.
(3) A structure for efficiently reflecting the return light is provided.
(4) The modulation element has an etendue that allows the etendue of the light source to increase during the recycling process.

  The first requirement is as described above.

  In order to satisfy the second requirement, it is necessary to apply an antireflection film to each optical component and to reduce the number of reflecting surfaces by integrating components that can be integrated. For example, it is desirable that an antireflection film is also applied to the glass surface constituting the discharge bulb. In FIG. 2, the PS conversion element, the condenser lens 10, and the second fly-eye lens surface 9 of the fly-eye integrator are optically brought into close contact with each other.

  The third requirement will be described later.

  The fourth requirement “Etendue of the modulation element” is expressed by the product of the illumination area illuminated by the modulation element and the solid angle of the illumination light. On the other hand, “Etendue of the light source” is expressed by the product of the emission area and the solid solid angle of the emitted light. For example, in a light source composed of a parabolic mirror and a discharge bulb, the “light source etendue” is the product of the area of the opening of the parabolic mirror and the radiant solid angle of the emitted light at that position. In the process of returning unnecessary light to the light source side and reflecting it again to the modulation element side, the etendue of the light source increases. When the etendue of the modulation element is relatively small compared to the etendue of the light source, the recycled light illuminates a range larger than the intended illumination range, and the recycling efficiency decreases.

[Configuration of light source to improve recycling efficiency (1)]
As described above, when the light source includes a parabolic mirror, the recycled light is completely at the same position and angle as the primary light when the unnecessary light returns to the opening of the parabolic mirror. It does not match. Further, the recycled light does not return to the light emitting point of the light source even when there is a deviation in the alignment of the optical element in manufacturing. As a structure in which this point is improved, as shown in FIG. 6, in a light source provided with a parabolic mirror 7, a surface 13b of a protective glass (face plate) 13 provided at the opening end of the parabolic mirror 7 is used. Alternatively, it is conceivable to add reflecting plates 14a and 14b serving as second reflecting elements to the back surface 13a. The reflecting plates 14a and 14b are located at the central portion and the peripheral portion of the protective glass 13, and may be provided by forming a thin film or a dielectric multilayer film made of a metal material such as aluminum or silver on the protective glass 13. Alternatively, a reflection plate having a substrate separate from the protective glass 13 may be provided in the vicinity of the reflection plate 13.

  The light emitting point is in the bulb 12 made of a glass tube, and an antireflection film 15 is formed on the surface of the glass tube.

  That is, in general, in the light source composed of the parabolic mirror 7 and the bulb 12, the entire area of the opening end of the parabolic mirror 7 is not effective as a light source, and as shown in FIG. The central portion and the peripheral portion, which are the front, are invalid areas where the illumination light reflected by the parabolic mirror 7 does not pass. Therefore, the reflectors 14a and 14b are formed in such invalid areas.

  The reflecting plates 14a and 14b are preferably formed as close to the light emitting point of the light source as possible. This is because, as shown in FIG. 7, when the reflectors 14a and 14b are separated from the light emitting point, the ratio of the luminous flux shielded by the glass tube of the bulb 12 in the recycled light increases. Therefore, as shown in FIG. 8, it is preferable that the reflecting plates 14 a and 14 b be formed on the back surface 13 a of the protective glass 13 to be close to the light emitting point, rather than be formed on the front surface 13 b of the protective glass 13. Further, it can be said that the positions of the reflecting plates 14a and 14b are preferably close to the effective range of the parabolic mirror 7. When the reflectors 14a and 14b are far from the effective range of the parabolic mirror 7, unnecessary primary light (light directly emitted from the light emitting point) cannot be sufficiently shielded, and reflected light to be returned to the light source side is reduced. This is because the ratio of reflection increases.

  Further, the reflection plate 14b around the protective glass 13 may be appropriately inclined with respect to the optical axis as shown in FIG. That is, in this case, the reflecting plate 14b has a conical surface or a shape that is a part of a spherical surface. When the reflecting plate 14 b is not tilted, the light beam reflected by the reflecting plate 14 b reaches a range that greatly spreads in the radial direction on the first fly-eye lens surface 8. By inclining the reflecting plate 14b, the light beam reflected by the reflecting plate 14b can be prevented from spreading on the first fly-eye lens surface 8. The inclination angle of the reflecting plate 14b is determined by the relationship between the focal length of the parabolic mirror 7 and the size of the light emitting point.

[Configuration of light source to improve recycling efficiency (2)]
As shown in FIG. 10, even when the light source is configured using a bulb 12, a spheroidal elliptical mirror 16 instead of the above-described parabolic mirror, and a protective glass 13, the parabolic mirror is used. As in the case of the light source using, the reflectors 14a and 14b are formed in an ineffective area on the protective glass 13 where the primary light is not transmitted. That is, the reflecting plates 14 a and 14 b are formed at the central portion and the peripheral portion of the protective glass 13.

  However, unlike the parabolic mirror, the elliptical mirror 16 is not effective simply by forming the reflection plates 14a and 14b on the protective glass 13. That is, in this light source, since the light emitting point is placed on the first focus of the elliptical mirror 16, the light (primary light) emitted from this light emitting point is on the second focus of the elliptical mirror 16. To form an image. Therefore, in order to make the recycled light effective, it is necessary to image the light beam reflected by the reflecting plate at the second focal point of the elliptical mirror 16. Therefore, condensing lenses 17a and 17b are disposed in the vicinity of the reflecting plates 14a and 14b. These condensing lenses 17a and 17b are circular and annular lenses disposed in the central portion and the peripheral portion of the protective glass 13 corresponding to the reflecting plates 14a and 14b, respectively. It is made to match the focus of. The recycled light that has passed through the second focal point of the elliptical mirror 16 by the condensing lenses 17a and 17b becomes telecentric in the first reflecting element as described above. Accordingly, the recycled light reflected by the first reflecting element returns to the second focal point of the elliptical mirror 16, and thereafter becomes an effective light beam.

[Configuration of light source to improve recycling efficiency (3)]
As shown in FIG. 11, the light source can be configured to include a bulb 12 having a parabolic mirror 7, a quarter-wave plate 18, and a reflective circularly polarizing plate 19. As described above, the phase change in the reflection by the parabolic mirror 7 is not limited to 180 °, and also changes depending on the incident angle and wavelength. Therefore, in this light source, the incident surface of the parabolic mirror 7 is aligned with P-polarized light or S-polarized light by the action of the quarter-wave plate 18 and the reflective circularly polarizing plate 19. As shown in FIG. 12, the quarter-wave plate 18 has a plurality of (even number) regions 18a, 18b, 18c, 18d, 18a ′, 18b in a radial pattern with the central axis of the parabolic mirror 7 as the axis of symmetry. ', 18c', and 18d '. The slow axis of each region is in a direction of 45 ° with respect to a straight line connecting the central portion of each region and the central axis of the parabolic mirror 7, and the center of the parabolic mirror 7. The direction is orthogonal to the slow axis of the region of positional relationship that is symmetric with respect to the axis. An ultraviolet and infrared cut filter (not shown) is formed between the quarter wavelength plate 18 and the protective glass 13 of the bulb 12.

  As the reflective circularly polarizing plate 19, a cholesteric liquid crystal polymer circularly polarizing plate can be used. Further, it is desirable that the quarter wavelength plate 18 functions in a wide wavelength range. An antireflection film is formed at the air interface.

  The light emitted from the bulb 12 is converted into linearly polarized light by passing through the quarter-wave plate 18 and reaches the reflective circularly polarizing plate 19. At this time, the polarization axis of this light is P-polarized light or S-polarized light with respect to the incident surface of the reflective circularly polarizing plate 19. In the reflective circularly polarizing plate 19, polarized light in one direction is reflected to the light source side.

  The light reflected by the reflective circularly polarizing plate 19 passes through the quarter-wave plate 18, is reflected twice by the parabolic mirror 7, and reaches the quarter-wave plate 18 again. At this time, this light is symmetric through the central axis of the parabolic mirror 7 with respect to the region (for example, 18a) of the quarter-wave plate 18 that is transmitted when reflected by the reflective circularly polarizing plate 19. It reaches the area (for example, 18a '). Since this light has already passed through the quarter-wave plate 18 and the reflective circularly polarizing plate 19, it is aligned with P-polarized light or S-polarized light, and no phase difference is generated. Therefore, by passing through the area of the quarter-wave plate 18 in which the slow axis is orthogonal, the circularly polarized light in the direction opposite to the initial incidence on the reflective circularly polarizing plate 19 is obtained. It passes through the mold circular polarizer 19. In this way, polarization conversion is performed in this light source.

  In FIG. 11, the quarter-wave plate 18 and the reflective circularly polarizing plate 19 are configured to be integrated with the protective glass 13 integrated with the parabolic mirror 7. Alternatively, a separate structure may be used.

  However, it is desirable that the quarter-wave plate 18 is disposed at a position as close as possible to the parabolic mirror 7. This is because when the quarter-wave plate 18 is arranged at a position away from the parabolic mirror 7, a light beam having a large tilt angle with respect to the optical axis is reflected twice by the parabolic mirror 7 and is again 1 This is because when the ¼ wavelength plate 18 is reached, there is a greater possibility that the ¼ wavelength plate 18 will not pass through the region of the ¼ wavelength plate 18 that is in a symmetrical relationship.

  Further, as the position of the reflective circularly polarizing plate 19 moves away from the parabolic mirror 7, the possibility that the reflected light from the reflective circularly polarizing plate 19 reaches the reflecting plate 14b at the peripheral portion increases. In this case, this light does not pass through the quarter-wave plate 18 and reaches the reflection plate 14b as circularly polarized light. When this light is reflected by the reflecting plate 14 b, the phase changes by 180 ° to become reverse circularly polarized light, and passes through the reflective circularly polarizing plate 19. In this case, since it is not affected by the reflection by the parabolic mirror 7 or the bulb 12, the efficiency of the illumination light may be improved.

  In addition, the combination of a quarter wavelength plate and a circularly polarizing plate as described above, but also a combination of a half (1/2) wavelength plate and a reflective linear polarizing plate, exhibits the same effect. It is possible to construct a light source.

[Configuration of light source to improve recycling efficiency (4)]
As shown in FIG. 13, the light source may include a bulb 12 having an elliptical mirror 16, a quarter-wave plate 18, a relay lens 20, a field lens 21, and a reflective circularly polarizing plate 19. .

  As shown in FIG. 14, in the case of a light source equipped with a parabolic mirror 7, the light beam deviating from the focal position of the parabolic mirror 7 is reflected by the reflective circularly polarizing plate 19 and enters the bulb 12 again. At this time, there is a possibility that light is shielded by a shield such as an electrode of the bulb 12. Therefore, in the light source provided with the elliptical mirror 16, as shown in FIG. 15, the light emitting point of the bulb 12 is arranged at the first focal position of the elliptical mirror 16 and relayed to the second focal position of the elliptical mirror 16. The lens 20 is disposed, and the reflection type circularly polarizing plate 19 is disposed at a substantially conjugate point with respect to the reflection position of the elliptical mirror 16 and the relay lens 20. The light incident on the reflective circularly polarizing plate 19 is set in a telecentric state by the field lens 21.

  The light beam reflected by the reflective circularly polarizing plate 19 returns to the same position where the primary light is reflected by the elliptical mirror 16. Then, the light beam reflected by the elliptical mirror 16 returns to a position that is symmetrical with the light emitting point with the first focal point of the elliptical mirror 16 as the center. In other words, the ratio of the light beam shielded by the discharge electrode of the bulb 12 is small.

  As in [Light source structure (3)] described above, the quarter-wave plate 18 is radially divided into a plurality of regions having different slow axis orientations as shown in FIG. Thus, it arrange | positions in the vicinity of the protective glass 13. FIG. Even if the quarter-wave plate 18 is disposed between the reflective circularly polarizing plate 19 and the field lens 21, the same effect can be obtained.

  The quarter-wave plate 18 desirably functions in a wide wavelength range. Further, an ultraviolet and infrared cut filter (not shown) is formed between the quarter wavelength plate 18 and the protective glass 13 of the discharge lamp.

  As the reflective circularly polarizing plate 19, a cholesteric liquid crystal polymer circularly polarizing plate can be used. An antireflection film 23 is formed at the air interface.

  The light emitted from the bulb 12 is converted into linearly polarized light by passing through the quarter-wave plate 18 and reaches the reflective circularly polarizing plate 19. At this time, the polarization axis of this light is P-polarized light or S-polarized light with respect to the incident surface of the reflective circularly polarizing plate 19. In the reflective circularly polarizing plate 19, polarized light in one direction is reflected to the light source side.

  The light reflected by the reflective circularly polarizing plate 19 passes through the quarter-wave plate 18, is reflected twice by the elliptical mirror 16, and reaches the quarter-wave plate 18 again. At this time, this light is symmetric through the central axis of the elliptical mirror 16 with respect to the region (for example, 18a) of the quarter-wave plate 18 that is transmitted when reflected by the reflective circularly polarizing plate 19. It reaches an area (for example, 18a ′). Since this light has already passed through the quarter-wave plate 18 and the reflective circularly polarizing plate 19, it is aligned with P-polarized light or S-polarized light, and no phase difference is generated. Therefore, by passing through the area of the quarter-wave plate 18 in which the slow axis is orthogonal, the circularly polarized light in the direction opposite to the initial incidence on the reflective circularly polarizing plate 19 is obtained. It passes through the mold circular polarizer 19. In this way, polarization conversion is performed in this light source.

  In addition, the combination of a quarter wavelength plate and a circularly polarizing plate as described above, but also a combination of a half (1/2) wavelength plate and a reflective linear polarizing plate, exhibits the same effect. It is possible to construct a light source.

[Configuration of lighting equipment to improve recycling efficiency (1)]
As shown in FIG. 16, the illumination device of the image display device according to the present invention includes the light source 24 configured as described above, the fly eye integrator 2, the condenser lens 10, the field lens 11, and the first reflective element 6. Composed. In this illuminating device, each divided element of the second fly-eye lens surface 9 of the fly-eye integrator 2 is a stop with respect to the corresponding divided element of the first fly-eye lens surface 8. That is, all the light beams that pass through the split elements of the corresponding second fly-eye lens surface 9 are imaged on the object to be illuminated. However, actually, the entire area of the aperture is not used, and there is an invalid area where the illuminance is low, as shown in FIG. In this illuminating device, the invalid area in the second fly-eye lens surface 9 is effectively used.

  In other words, in this illumination device, the reflector 14 serving as the second reflecting element is disposed between the second fly-eye lens surface 9 of the fly-eye integrator 2 and the condenser lens 10. As described above, the reflection plate 14 is disposed between the second fly-eye lens surface 9 of the fly eye integrator 2 and the PS conversion element when the PS conversion element exists. The

  The reflecting plate 14 exists in a range that does not interfere with the primary light from the light source. That is, the reflecting plate 14 has an opening pattern having a structure corresponding to the illuminance distribution on the second fly-eye lens surface 9 of the fly-eye integrator 2 shown in FIG. 17, or has a stripe structure. Yes.

  In this illuminating device, the recycled light reflected by the first reflective element 6 can be returned to the object to be illuminated again by returning it to the area other than the opening of the reflector 14, and the recycled light can be used efficiently. can do.

  Since the reflecting plate 14 is arranged on the light source side of the condenser lens 10, a relay condenser illumination system is configured by the condenser lens 10 and the field lens 11 for the recycled light. Here, the condenser lens 10 functions as a relay lens. Further, this optical system is a telecentric optical system for the first reflective element 6 and the reflective plate 14, that is, an optical system in which the principal ray is parallel to the optical axis.

  When the recycled light reflected by the reflecting plate 14 is reflected again by the first reflecting element 6, this light returns to the light source 24 side in the reverse direction along the optical path followed by the primary light. By repeating this process, recycling of the illumination light is achieved.

  The first reflecting element 6 is inclined with respect to the optical axis. Regarding the inclination direction of the first reflecting element 6, two kinds of directions, a horizontal direction and a vertical direction, are conceivable. The illuminance distribution of the recycled light on the second fly-eye lens surface 9 of the fly-eye integrator 2 when the first reflecting element 6 is inclined in the horizontal direction is the opening pattern in the reflector 14 as shown by the broken line in FIG. As a result, a bright portion appears at a position shifted laterally with respect to FIG. Then, the illuminance distribution of the recycled light on the second fly-eye lens surface 9 of the fly-eye integrator 2 when the first reflecting element 6 is tilted in the vertical direction is as shown in the broken line in FIG. A bright portion appears at a position shifted in the vertical direction with respect to the opening pattern.

  A part of the light returning to the reflection plate 14 in this manner protrudes outside the outer dimension of the second fly-eye lens surface 9 of the fly-eye integrator 2, but the outer diameter of the condenser lens 10 is increased. If this is done, all of the light returning to the reflector 14 can be captured. Further, of the light returning to the reflecting plate 14, the portion overlapping with the opening pattern indicated by the solid line in FIGS. 18 and 19 returns to the light source 24 through the opening pattern, so that it is used again as illumination light. It will not be a loss.

  Further, the first reflecting element 6 may be shifted in parallel to the optical axis by a predetermined amount together with the condenser lens 11 instead of being inclined with respect to the optical axis. Here, the predetermined amount by which the optical system after the condenser lens 11 is displaced with respect to the optical axis is about 1/4 of the pitch of the fly-eye lens element.

  In addition, it is desirable that the surface of the reflecting plate 14 has good flatness from the viewpoint of recycling efficiency of illumination light. However, the recycled light reflected by the first reflecting element 6 returns to the reflecting plate 14 as a pattern inverted with respect to the opening pattern of the reflecting plate 14. Therefore, in the case where uniformity is required for illumination with recycled light, the surface of the reflector 14 may be an appropriate scattering surface.

  Furthermore, this illuminating device can be configured to include two groups of fly-eye integrators 2 and 25 as shown in FIG. In this case, the uniformity of the recycled light can be improved.

  That is, the first fly eye integrator 2 is composed of elements that are generally similar to the object to be illuminated. The second fly eye integrator 25 disposed between the first fly eye integrator 2 and the light source 24 may have a shape different from that of the first fly eye integrator 2.

  The second fly's eye integrator 25 constitutes a relay condenser illumination system, and the reflector 14 as the second reflective element is disposed in a range that does not interfere with the primary light in the vicinity of the aperture position.

  Further, the optical axis of the condenser lens 10 and thereafter (the condenser lens 10 and the first reflecting element 6) is approximately ¼ of the element pitch of the first fly-eye integrator 2 and is parallel to the optical axes of other optical systems. It is shifted. The element pitches of the first fly eye integrator 2 and the second fly eye integrator 25 are set to be different from each other.

  In this illumination device, the recycled light reflected by the first reflecting element 6 forms an image of the reflected light on each element of the first fly-eye lens surface 8 of the first fly-eye integrator 2. Since the element pitch of the second fly eye integrator 25 is different from the element pitch of the first fly eye integrator 2, the recycled light reaches the reflection plate 14 and is reflected by the reflection plate 14. When the first fly-eye lens surface 8 of the eye integrator 1 is reached, a pattern different from that when the eye flyer first returns to the first fly-eye lens surface 8 is formed. Therefore, the recycled light passes through the first fly eye integrator 2 and reaches the first reflecting element 6, and at this time, the intensity is in a uniform state.

[Configuration of lighting device to improve recycling efficiency (2)]
In addition, as shown in FIG. 21, this illumination device uses the optical axis of the optical system (condenser lens 10, field lens 11, and first reflecting element 6) after the condenser lens 10 as to the optical axis of the light source 24. It may be configured to be shifted in parallel. The fly eye integrator 2 is arranged between the light source 24 and the condenser lens 10 in a range corresponding to both the light source 24 and the optical system after the condenser lens 10. The reflector 14 is disposed on the light source 24 side of the fly-eye integrator 2 at a position that is symmetric with respect to the light source 24 via the optical axis of the optical system after the condenser lens 10.

  In this illuminating device, a part of the primary light reaching the first reflecting element 6 from the light source 24 reaches the reflecting plate 14 disposed on the light source 24 side of the fly eye integrator 2 as recycled light, and the fly eye integrator. The object to be illuminated is efficiently illuminated in a state of being uniformed by 2.

When the recycled light is reflected again by the first reflecting element 6, the recycled light traces the optical path followed by the primary light and returns to the light source 24. By repeating this process, recycling of the illumination light is achieved.
[Configuration of lighting equipment to improve recycling efficiency (3)]
Moreover, this illuminating device can also be comprised using the rod integrator 26, as shown in FIG. The rod integrator 26 is a prismatic optical element made of a transparent material, and a light beam enters from one end and exits from the other end. This illuminating device includes a light source 27 having an elliptical mirror 16, a rod integrator 26, and a relay condenser optical system disposed between the light source 27 and the rod integrator 26. The relay condenser optical system includes a condenser lens 28 and a relay lens 29. The condenser lens 28 is disposed at the second focal position of the elliptical mirror 16, and the relay lens 29 is disposed at the focal position of the condenser lens 28.

  In the vicinity of one end where the light beam from the light source 27 of the rod integrator 26 is incident, the reflecting plate 14 having an opening is disposed. As shown in FIGS. 23A and 23B, the reflecting plate 14 can be formed, for example, on the end surface of the rod integrator 26 on the light source 27 side.

  The relay lens systems 30 and 20, the field lens 21, and the first reflecting element 6 are disposed on the light beam incident end side of the rod integrator 26.

  When the recycled light reflected by the first reflecting element 6 returns to the light beam incident end of the rod integrator 26, the illuminance is made uniform by the rod integrator 26. Therefore, the recycled light that has returned to the part other than the opening of the reflecting plate 14 is reflected by the reflecting plate 14. The luminous flux reflected by the reflecting plate 14 efficiently illuminates the object to be illuminated in a state of being uniformed by the rod integrator 26 as in the case of the primary light. The recycled light that has passed through the opening returns to the light source 27. By repeating this process, recycling of the illumination light is achieved.

  In addition, as a light source, you may use what has a parabolic mirror.

[Configuration of lighting equipment to improve recycling efficiency (4)]
In addition, as shown in FIG. 24, this illumination device can also be configured by shifting a part of the optical axis of the optical system in parallel to the optical axes of other optical systems. This illuminating device further includes a condenser lens 10 between the relay lens 20 and the field lens 21 in the illuminating device described above with reference to FIG. To the relay lens 20 are shifted in parallel to the optical axis of the optical system. On the light source side of the condenser lens 10, a reflector 14 c is disposed at a position symmetrical about the optical axis of the optical system after the condenser lens 10 with respect to the optical axis of the optical system up to the relay lens 20. .

  In this front device, the recycled light reflected by the first reflecting element 6 reaches the reflecting plate 14 c, is reflected by the reflecting plate 14 c, passes through the condenser lens 10 and the field lens 21, and again becomes the first reflecting element 6. To reach. Here, the recycled light reflected again by the first reflective element 6 returns to the rod integrator 26. When the recycled light returns to the end of the rod integrator 26 on the light source side, the illuminance is made uniform by the rod integrator 26. Therefore, the recycled light that has returned to the part other than the opening of the reflecting plate 14 is reflected by the reflecting plate 14. The luminous flux reflected by the reflecting plate 14 efficiently illuminates the object to be illuminated in a state of being uniformed by the rod integrator 26 as in the case of the primary light. The recycled light that has passed through the opening returns to the light source 27. By repeating this process, recycling of the illumination light is achieved.

[Configuration of Image Display Device with Polarization Conversion Function (1)]
The image display apparatus according to the present invention includes the light source 24 having the above-described configuration as shown in FIG. This light source includes a bulb 12 and a parabolic mirror 7. And this image display apparatus is provided with the reflective polarizing plate 6 as a 1st reflective element, and has a polarization conversion function.

  That is, this image display device is configured by sequentially arranging a light source 24, a fly eye integrator 2, a reflector 14, a condenser lens 10, a field lens 21, a reflective polarizing plate 6, and a modulation element 31 at a predetermined interval. . The reflective polarizing plate 6 is disposed to be inclined with respect to the optical axis. As described above, the inclination angle of the reflection type polarizing plate 6 is such that when the recycled light reflected by the reflection type polarizing plate 6 returns to the reflection plate 14, it mainly reaches an ineffective portion shifted from the opening pattern. It has become.

  As the reflective polarizing plate 6, a cholesteric liquid crystal polymer circular polarizing plate can be used. Further, by forming an antireflection film at the air interface of the substrate on which the cholesteric liquid crystal polymer is formed, the polarization separation characteristic can be improved as shown in FIG. In FIG. 26, the selective reflection range of the cholesteric liquid crystal is set to 420 nm to 690 nm, and (A) shows the spectral transmittance of counterclockwise circularly polarized light when the antireflection film is formed. B) shows the spectral transmittance of the clockwise circularly polarized light when the antireflection film is formed, and (C) shows the spectral transmittance of the counterclockwise circularly polarized light when the antireflection film is not formed. , (D) shows the spectral transmittance of clockwise circularly polarized light when the antireflection film is not formed.

  The illumination light emitted from the light source 24 passes through the fly-eye integrator 2, the opening pattern of the reflecting plate 14, the condenser lens 10 and the field lens 11, and reaches the reflective polarizing plate 6, as shown in FIG. In this reflection type polarizing plate 6, one circularly polarized light is transmitted and the other circularly polarized light is reflected. The reflected circularly polarized light returns to the reflecting plate 14 and is reflected by the reflecting plate 14 to become reversely circularly polarized light, reaches the reflecting polarizing plate 6 again, and passes through the reflecting polarizing plate 6. . The light transmitted through the reflective polarizing plate 6 in this way reaches the modulation element 31 and is subjected to spatial modulation according to the display image by the modulation element 31.

  If linearly polarized light needs to be incident on the modulation element 31, a quarter-wave plate may be disposed between the reflective polarizing plate 6 and the modulation element 31. Furthermore, unnecessary polarized light can be blocked by adding an absorption type polarizing plate.

  Further, as the reflective polarizing plate, a reflective linear polarizing plate may be used. In this case, a quarter wavelength plate is disposed on the reflecting plate 14 or on the light source side of the reflective linearly polarizing plate.

[Configuration of Image Display Device with Polarization Conversion Function (2)]
As shown in FIG. 27, this image display device includes a light source 24 comprising a bulb 12 and a parabolic mirror 7, a quarter wavelength plate 18, a fly eye integrator 2, a reflective polarizing plate 6, a condenser lens 10, and a field lens. 11 and the modulation element 31 may be sequentially arranged at a predetermined interval.

  In this image display device, a cholesteric liquid crystal polymer circularly polarizing plate can be used as the reflective polarizing plate 6. Further, as shown in FIG. 12, the quarter-wave plate 18 has a plurality of (even number) regions 18a, 18b, 18c, 18d, 18a ′ in a radial pattern with the central axis of the parabolic mirror 7 as the axis of symmetry. , 18b ′, 18c ′, and 18d ′, and the slow axis of each region is a direction that forms 45 ° with respect to a straight line that connects the central portion of each region and the central axis of the parabolic mirror 7, In addition, the direction is perpendicular to the slow axis of the region of positional relation that is symmetric with respect to the central axis of the parabolic mirror 7.

  The light emitted from the light source 24 reaches the reflective polarizing plate 6 through the quarter-wave plate 18. One circularly polarized component of this light is transmitted through the reflective polarizing plate 6 and the other circularly polarized component is reflected to the light source 24 side. Since the second fly-eye lens surface of the fly eye integrator 2 and the light emitting part (bulb 12) of the light source 24 are in a conjugate relationship, the light reflected by the reflective polarizing plate 6 is transmitted to the light emitting part (bulb 12). Return. The light returning to the light source side in this way is converted into linearly polarized light by passing through the quarter-wave plate 18 and reaches the parabolic mirror 7.

  Here, the direction of the slow axis in the quarter-wave plate 18 is 45 with respect to a straight line connecting the central portion of each region and the central axis of the parabolic mirror 7, that is, the incident surface of the parabolic mirror 7. The azimuth is set to °. Therefore, the linear polarization axis after returning from the reflective polarizing plate 6 and passing through the quarter-wave plate 18 is P-polarized light or S-polarized light with respect to the incident surface of the parabolic mirror 7. This light is reflected twice by the parabolic mirror 7 without causing a phase change, and passes through the quarter-wave plate 18 again.

  In this way, the light transmitted through the quarter-wave plate 18 a total of three times becomes circularly polarized light in the direction of transmitting through the reflective polarizing plate 6. In this way, recycling of the light reflected by the reflective polarizing plate 6 is achieved, and the efficiency of the polarized light after passing through the reflective polarizing plate 6 is improved.

[Configuration of Image Display Device with Polarization Conversion Function (3)]
In addition, as shown in FIG. 28A, this image display device includes a light source 27 having an elliptical mirror 16, a relay lens 28, a field lens 29, a reflector 14 having an opening, a rod integrator 26, a condenser. It is configured by adding a modulation element 31 to an illumination device including a lens 30, a relay lens 20, a reflection plate 14 c, a condenser lens 10, a field lens 21, and a reflective polarizing plate 6. The optical axis of the optical system after the condenser lens 10 is arranged in parallel with the optical axis of the optical system from the light source 27 to the relay lens 20. In this image display device, the polarization conversion function is achieved by the illumination device 27 and the reflective polarizing plate 6. As in the embodiment described above, a cholesteric liquid crystal polymer circularly polarizing plate is used as the reflective polarizing plate 6.

  The illumination light emitted from the light source 27 passes through the relay lens 28, the field lens 29, the rod integrator 26, the condenser lens 30, the relay lens 20, the condenser lens 10, and the field lens 21, and reaches the reflective polarizing plate 6, and is shown in FIG. As shown in (b), one circularly polarized light is transmitted through the reflective polarizing plate 6 and the other circularly polarized light is reflected. The reflected circularly polarized light reaches the reflecting plate 14c, and is reflected by the reflecting plate 14c to become reversely polarized circularly polarized light. This light reaches the reflective polarizing plate 6 again and passes through the reflective polarizing plate 6. The light transmitted through the reflective polarizing plate 6 in this way reaches the modulation element 31 and is subjected to spatial modulation according to the display image by the modulation element 31.

  If linearly polarized light needs to be incident on the modulation element 31, a quarter-wave plate may be disposed between the reflective polarizing plate 6 and the modulation element 31. Furthermore, unnecessary polarized light can be blocked by adding an absorption type polarizing plate.

  Further, as the reflective polarizing plate, a reflective linear polarizing plate may be used. In this case, a quarter wavelength plate is disposed on the reflecting plate 14 or on the light source side of the reflective linearly polarizing plate.

[Configuration of Image Display Device with Polarization Conversion Function (4)]
This image display device includes a light source 27 having an elliptical mirror 16, a relay lens 28, a field lens 29, and an opening, as shown in FIG. 29 (a), FIG. 30 (a) and FIG. The reflection plate 14, the rod integrator 26, the condenser lens 30, the relay lens 20, the reflection plate 14 c, the condenser lens 10, and the field lens 21 are provided, and a modulation element 31 is disposed via a polarization beam splitter 32. Also good. The optical axis of the optical system after the condenser lens 10 is shifted in parallel to the optical axis of the optical system from the light source 27 to the relay lens 20. A quarter wavelength plate 34 is disposed between the condenser lens 10 and the reflection plate 14c. In this image display device, the polarization conversion function is achieved by the polarization beam splitter 32.

  That is, as shown in FIG. 29A, the reflecting plate 33 is disposed at a position where the field lens 21 passes through the polarization beam splitter 32, and the modulation element 31 is disposed on the side surface of the polarization beam splitter 32. The reflection plate 33 and the modulation element 31 are arranged such that their optical path lengths from the field lens 21 are equal to each other via a reflection surface in the polarization beam splitter 32.

  In this image display device, the light emitted from the light source 27 reaches the polarization beam splitter 32 through the illumination optical system. As shown in (b) of FIG. 29, the illuminating light is reflected by the reflecting surface of the polarizing beam splitter 32 so that the S-polarized light with respect to the reflecting surface of the polarizing beam splitter 32 reaches the modulation element 31. The P-polarized light passes through the reflecting surface and reaches the reflecting plate 33 and is reflected by the reflecting plate 33. The recycled light reflected by the reflecting plate 33 traces the optical path in the reverse direction, is reflected by the reflecting plate 14c through the quarter wavelength plate 34, and is again converted to S-polarized light by passing through the quarter wavelength plate 34. Then, it reaches the polarization beam splitter 32 again. At this time, since the recycled light is S-polarized light with respect to the reflection surface of the polarization beam splitter 32, it is reflected by the reflection surface and illuminates the modulation element 31.

  The direction in which the optical axis of the optical system after the condenser lens 10 is shifted is such that the distance between the field lens 21 and the reflecting surface of the polarization beam splitter 32 is changed by the movement of the optical axis, as shown in FIG. It is desirable that the direction is not. This is to allow the spread of the incident angle of the light beam corresponding to the movement of the optical axis. In addition, this configuration also has an effect of improving peak luminance described later.

  If the desired extinction ratio cannot be obtained by one beam splitter, a configuration in which a polarizing beam splitter is added as shown in FIGS. 30A and 30B is used. Can do. That is, in this image display device, the reflection plate 33 is disposed at a position that has passed through the two polarization beam splitters 35 and 32 from the field lens 21, and the modulation element 31 is disposed on the side surface of the second polarization beam splitter 32. Deploy. A reflecting plate 37 is disposed on the side surface of the first polarizing beam splitter 35 via an optical path length adjustment block 36. The reflection plate 33, the modulation element 31, and the reflection plate 37 are arranged such that the optical path lengths from the field lens 21 are equal to each other through the reflection surfaces in the polarization beam splitters 35 and 32. The two polarization beam splitters 35 and 32 are in a positional relationship in which the directions of reflected light are orthogonal when the light beam is reflected on the reflection surface.

  In this image display device, similarly to the image display device shown in FIG. 29A, the recycled light can be returned to the modulation element 31, but two polarizing beam splitters are overlapped. A higher extinction ratio can be obtained.

  Further, when three modulation elements corresponding to the three primary colors of R (red), G (green), and B (blue) are used as the modulation elements, as shown in FIG. A reflecting plate 33 is disposed at a position that has passed through the beam splitter 32 and the optical path length adjustment block 36, and modulation elements 31 a, 31 b, 31 c for the respective colors are provided on the side surfaces of the polarizing beam splitter 32 via color separation prisms 37, 38, 39. Place. The reflection plate 33 and the modulation elements 31a, 31b, and 31c pass through the optical path length adjustment block 36 and the color separation prisms 37, 38, and 39 through the reflection surface in the polarization beam splitter 32, and are mutually connected to the field lens 21. The optical path lengths from are set equal.

  In this image display device, the illumination light is separated into three primary colors of R (red), G (green), and B (blue) by the color separation prisms 37, 38, 39, and the modulation elements 31a, 31b, 31c are displayed on the display image. The image is displayed by performing modulation according to each of the R (red), G (green), and B (blue) color components, and the light beams that have passed through the modulation elements 31a, 31b, and 31c are combined again.

  In FIG. 31, since the direction of the optical axis deviation of the optical system after the condenser lens 10 is perpendicular to the paper surface, the optical axis deviation is not displayed in the figure, but the light source 27 The configuration of the optical system from the field lens 21 to the field lens 21 is the same as that shown in (a) of FIG. 29 and (a) of FIG.

[Configuration of image display device provided with reflective color filter]
The image display apparatus according to the present invention includes a PS conversion element 40 as shown in FIG. 32A and FIG. 33, and in the modulation element 31, a color filter layer made of an interference filter is provided for each pixel. It can also be configured as being arranged corresponding to. In this image display device, a light source 24 having a parabolic mirror 7, a fly-eye integrator 2, a reflector 14 having an aperture pattern, a PS conversion element 40, a condenser lens 10, a field lens 11, and a modulation element 31 are sequentially provided. It is arranged and configured. 32A is a horizontal cross-sectional view, and FIG. 33 is a vertical cross-sectional view. The modulation element 31 is inclined with respect to the optical axis, as shown in (b) of FIG.

  As described above with reference to FIG. 46, the PS conversion element 40 is formed by alternately switching a plate glass having a polarization separation film formed of a multilayer film made of an inorganic material on the surface and a plate glass having a reflection surface formed on the surface. The bonded glass block is configured by cutting into a plate shape along a cut surface inclined with respect to the bonded surface. When a light beam mixed with P-polarized light and S-polarized light is incident on the PS conversion element 40, the P-polarized light and the S-polarized light are separated in the polarization separation film. -Separated for each layer constituting the S conversion element 40 and emitted. On this exit side, a λ / 2 plate is arranged at the exit portion corresponding to S-polarized light or P-polarized light, so that only one polarization component of P-polarized light or S-polarized light can be obtained. The luminous flux having is obtained.

  As shown in FIG. 34, the modulation element 31 includes a layer in which a transparent substrate 41, a reflective light shielding layer 42 and a reflective color filter 43 are sequentially arranged, a transparent electrode 44, an alignment layer 45, a liquid crystal layer 46, an alignment layer 47, It has a structure in which TFT substrates 48 subjected to alignment treatment are sequentially laminated. The reflective color filter 43 is an interference filter or the like, and has a function of transmitting predetermined color light and reflecting it without absorbing unnecessary colors other than the predetermined color light.

  In this image display device, the reflective color filter 43 and the reflective light shielding layer 42 function as a first reflective element. The reflective color filter 43 and the reflective light shielding layer 42 are inclined with respect to the optical axis together with the modulation element 31. The inclination direction of the reflection type color filter 43 and the reflection type light shielding layer 42 is a direction rotated about a direction perpendicular to the longitudinal direction of the bonding surface in the PS conversion element 40.

  In this image display device, the primary light emitted from the light source 24 is reflected by the reflective color filter 43 and the reflective light shielding layer 42 as unnecessary light that does not pass through each reflective color filter 43. For example, in a color filter for R (red), B (red) and G (red) are reflected and returned to the reflecting plate 14 as recycled light. The same applies to the color filters for other colors. In this way, the light beam returned to the reflecting plate 14 and reflected by the reflecting plate 14 reaches a position having a symmetrical relationship with respect to the optical axis in the modulation element 31 again. At this time, since the recycled light does not necessarily return to the filter position of the same color as when reflected as unnecessary light, a recycling effect is produced.

  In FIG. 32A and FIG. 33, a P-S conversion element 40 having a general configuration is used. However, instead of the PS conversion element 40, a reflective polarized light is used. It is good also as using a board. In this case, the inclination direction of the reflective polarizing plate and the inclination direction of the layer composed of the reflective color filter and the reflective light shielding layer (inclination direction of the modulation element 31) are orthogonal to each other. In addition, by using a light source including a quarter-wave plate that is radially divided into a plurality of (even number) regions with the optical axis as a symmetry axis, it is not necessary to use a PS conversion element. . In this case, since there is no increase in Etendue due to the use of the PS conversion element, the recycling efficiency by reflection in the reflective color filter is improved. That is, it is effective when there is no margin in etendue in the modulation element.

  Further, tilting the modulation element also tilts the optical axis of a projection lens (not shown) that forms an image of the modulation element on the screen. When the imaging characteristics on the screen deteriorate due to the inclination of the modulation element with respect to the optical axis of the projection lens, the optical axis of the projection lens may be inclined according to the inclination angle of the modulation element.

  Further, as the reflective color filter, a color filter obtained by adjusting the spiral pitch of the cholesteric liquid crystal polymer layer corresponding to each pixel may be used.

[Configuration of Illumination Device for Reflective Modulation Element with Reflective Color Filter]
In addition, as shown in FIG. 35, the image display device according to the present invention includes an elliptical mirror 16 and a quarter-wave plate 18 that is radially divided into a plurality (even numbers) of regions with the optical axis as a symmetry axis. A light source 27, a relay lens block 49 sandwiching a reflector 14 and a quarter-wave plate 50 having an annular portion formed in the center, a field lens 21, and a reflective circularly polarizing plate 19 The quarter-wave plate 51, the fly eye integrator 2, the condenser lens 10, the field lens 11, and the polarization beam splitter 32 may be sequentially arranged.

  In this image display device, the optical axis of the optical system after the field lens 11 is shifted in parallel to the optical axis of the optical system up to the condenser lens 10. On the side surface of the polarization beam splitter 32, a reflective modulation element 31 in which a color filter layer made of an interference filter is disposed corresponding to each pixel is disposed.

  In this image display device, the modulation element 31 is illuminated with S-polarized light on the reflection surface of the polarization beam splitter 32, and the modulated P-polarized light is transmitted through the polarization beam splitter 32 and projected by a projection lens (not shown). Become.

  As shown in FIG. 36, the modulation element 31 in this image display device includes a substrate 41, a reflective color filter 43, a transparent electrode 44, an alignment layer 45, a liquid crystal layer 46, an alignment layer 47, a reflective electrode 52, and an active matrix substrate 53. Are sequentially stacked.

  In the modulation element 31, as shown in FIG. 37, the reflective electrode 52 is formed corresponding to the effective pixel range, and a reflecting plate 54 is formed in the invalid area around the effective pixel range. It is desirable that In general, the range in which the modulation element 31 is illuminated is larger than the effective pixel area in order to allow a sufficient assembling accuracy. By making the reflector 54 larger than the illumination range, it is possible to recycle the illumination light illuminated in the invalid area other than the display range.

  In this image display device, the reflective color filter 43, the reflective electrode 52, and the reflective plate 54 function as a first reflective element. In this embodiment, the color use efficiency is improved and the peak luminance is improved.

  In this image display device, the light beam emitted from the bulb 12 in the light source 27 is aligned with polarized light in a certain direction by the polarization conversion function provided in the light source 27, that is, S-polarized light with respect to the reflection surface of the polarization beam splitter 32, The modulation element 31 is illuminated.

  As for the primary light emitted from the light source 27, unnecessary light that does not pass through the color filter 43 is reflected by the reflective color filter 43 in the modulation element 31. For example, in a color filter for R (red), B (blue) and G (green) are reflected and return to the reflecting plate 14 as recycled light. Here, the light that has reached the reflecting plate 14 passes through the quarter-wave plate 50 on the reflecting plate 14 to become linearly polarized light. The recycled light reflected by the reflecting plate 14 passes through the reflective circularly polarizing plate 19 as circularly polarized light. The recycled light reaches the reflective color filter 43 again. At this time, since the recycled light does not necessarily return to the filter position of the same color as when reflected as unnecessary light, a recycling effect is produced.

  Similarly, light that is not modulated by the modulation element 31 is returned to the reflecting plate 14 and is made uniform, and then illuminates the entire modulation element 31. Then, the light reflected by the reflective color filter 43 and the light not subjected to the modulation pass through the opening at the center of the reflecting plate 14 and return to the light emitting point of the light source 27.

  Of the light reaching the reflective circularly polarizing plate 19 from the light source 27, the light that is circularly polarized in the direction reflected by the reflective circularly polarizing plate 19 is reflected by the reflective circularly polarizing plate 19. Then, the light source 27 returns to the light emitting point again. When this light reaches the reflective circularly polarizing plate 19 again, it becomes circularly polarized light in the direction of transmitting through the reflective circularly polarizing plate 19 and is transmitted through the reflective circularly polarizing plate 19 to 1 / When transmitted through the four-wavelength plate 51, it becomes S-polarized light with respect to the reflection surface of the polarization beam splitter 32 and illuminates the modulation element 31. By repeating this process, the recycling effect is improved.

[Configuration of Recyclable Sequential Color Image Display Device]
As shown in FIG. 38, the image display device includes a light source 24 having a parabolic mirror 7, a fly-eye integrator 2, a reflector 14 having an opening pattern, a PS conversion element 40, a condenser lens 10, a field. The lens 11, the sequential color shutter 55, the reflective polarizing plate 6, and the modulation element 31 can be arranged in sequence. In this image display device, the optical axis of the optical system after the condenser lens 10 is shifted in parallel to the optical axis of the optical system from the light source 24 to the reflecting plate 14.

  In this image display device, color display using a single plate is realized as in the above-described embodiment, but sequential color display is used as the color display means. That is, the reflective polarizing plate 6 is used as an analyzer for the sequential color shutter 55. In this illumination optical system, unnecessary colors that are not involved in image display at each time point are reflected by the reflective polarizing plate 6 to be returned to the reflecting plate 14 to enable recycling of the illumination light.

[Configuration of lighting apparatus for improving peak luminance (1)]
Further, this image display apparatus can be configured to include two groups of fly eye integrators 2 and 25 as shown in FIG. In this case, the uniformity of the recycled light can be improved.

  That is, this image display apparatus includes a light source 24 having a parabolic mirror 7, a fly eye integrator 25, a reflector 14, a fly eye integrator 2, a PS conversion element 40, a condenser lens 10, a field lens 11, and a polarization beam splitter. 32 are sequentially arranged, and a modulation element (reflection type liquid crystal modulation element) 31 is arranged on the side surface of the polarization beam splitter 32. The light transmitted through the polarization beam splitter 32 through the modulation element 31 is projected onto the screen 68 by the projection lens 67 as shown in FIG.

  The first fly eye integrator 2 is composed of elements that are generally similar to the object to be illuminated. The second fly eye integrator 25 disposed between the first fly eye integrator 2 and the light source 24 may have a shape different from that of the first fly eye integrator 2.

  The second fly's eye integrator 25 constitutes a relay condenser illumination system, and the reflector 14 as the second reflective element is disposed in a range that does not interfere with the primary light in the vicinity of the aperture position.

  Further, the optical axis of the optical system after the condenser lens 10 is shifted in parallel to the optical axes of the other optical systems by about ¼ of the element pitch of the first fly-eye integrator 2. The element pitches of the first fly eye integrator 2 and the second fly eye integrator 25 are set to be different from each other.

  In this image display device, the recycled light that returns to the light source 24 side through the modulation element 31 forms an image of the reflected light on each element of the first fly-eye lens surface 8 of the first fly-eye integrator 2. Since the element pitch of the second fly eye integrator 25 is different from the element pitch of the first fly eye integrator 2, the recycled light reaches the reflection plate 14 and is reflected by the reflection plate 14. When the first fly-eye lens surface 8 of the eye integrator 1 is reached, a pattern different from that when the eye flyer first returns to the first fly-eye lens surface 8 is formed. Therefore, the recycled light passes through the first fly eye integrator 2 and reaches the first reflecting element 6, and at this time, the intensity is in a uniform state.

  In this image display device, a color separation / synthesis prism may be provided in order to perform color display, and a color filter may be provided as in the above-described embodiment. The direction in which the optical axis of the optical system after the condenser lens 10 is shifted is preferably a direction in which the distance between the field lens 21 and the reflecting surface of the polarization beam splitter 32 does not change due to the movement of the optical axis. This is to allow the spread of the incident angle of the light beam corresponding to the movement of the optical axis.

  Further, instead of the PS conversion element 40, another polarization conversion means may be provided. For example, as shown in FIGS. 40A and 40B, a reflection plate 33 that reflects light emitted from the field lens 11 and transmitted through the polarization beam splitter 32 is provided, and the fly-eye integrator 2 and the condenser lens are provided. It is good also as providing the reflecting plate 14 between 10. The reflector 33 is inclined with respect to the optical axis. The inclination direction of the reflecting plate 33 is a direction orthogonal to the direction of deviation of the optical axis of the optical system after the condenser lens 10.

  In addition, by using a light source including a quarter-wave plate that is radially divided into a plurality of (even number) regions with the optical axis as a symmetry axis, it is not necessary to use a PS conversion element. . In this case, since there is no increase in Etendue due to the use of the PS conversion element, the recycling efficiency by reflection in the reflective color filter is improved. That is, it is effective when there is no margin in etendue in the modulation element.

  In the case of this structure, the illumination light that has not been modulated by the modulation element 31 returns to the light source 24 side through the polarization beam splitter 32 as recycled light. The recycled light reflected by the reflection plate 14 is averaged by the fly eye integrator 2 and uniformly illuminates the modulation element 31.

  In this case, a bright portion in the dark display screen can be displayed brighter. As shown in FIG. 41, the relationship between the peak luminance and the average luminance is such that the larger the Etendue of the modulation element, the more it can be recycled, and the lower the average luminance of the display screen, Shows an exponential rise curve. Since the black level also rises at the same ratio, the contrast of the display device itself does not change. However, when the black level rise due to external light reflection determines the contrast as the projection device, the contrast is improved.

  In general, even in a configuration having a reflection type modulation element and a polarization beam splitter, unnecessary light returns to the light source side. However, as shown in the above-described embodiment, the unnecessary light is positively and efficiently added. If there is no means for recycling by returning to the modulation element side, the recycling effect is small.

[Configuration of lighting apparatus for improving peak luminance (2)]
Further, as shown in FIG. 42, this image display device includes a light source 27 having an elliptical mirror 16, a relay lens 28, a field lens 29, a reflector 14 having an opening, a rod integrator 26, a condenser lens 30, and a relay lens. 20, the reflection plate 14c, the condenser lens 10, the field lens 21, the reflection type polarizing plate 6, the transmission type modulation element 31, and the reflection type polarizing plate 6 serving as an analyzer can be sequentially arranged. The optical axis of the optical system after the condenser lens 10 is arranged in parallel with the optical axis of the optical system from the light source 27 to the relay lens 20.

  In this image display device, the polarization conversion function is achieved by the illumination device 27 and the reflective polarizing plate 6. As in the embodiment described above, a cholesteric liquid crystal polymer circularly polarizing plate is used as the reflective polarizing plate 6.

  The illumination light emitted from the light source 27 passes through the relay lens 28, the field lens 29, the rod integrator 26, the condenser lens 30, the relay lens 20, the condenser lens 10, and the field lens 21, and reaches the reflective polarizing plates 6 and 6. In the reflective polarizing plates 6 and 6, one circularly polarized light is transmitted and the other circularly polarized light is reflected. The reflected circularly polarized light reaches the reflecting plate 14c, and is reflected by the reflecting plate 14c to become reversely polarized circularly polarized light. This light reaches the reflective polarizing plate 6 again and passes through the reflective polarizing plate 6. The light transmitted through the reflective polarizing plate 6 in this way reaches the modulation element 31 and is subjected to spatial modulation according to the display image by the modulation element 31.

  In this image display device, in the reflective polarizing plate 6 serving as an analyzer, a cholesteric liquid crystal polymer circular polarizing plate is formed inside the modulation element 31 as shown in FIG. That is, the modulation element 31 has a structure in which the TFT substrate 48, the alignment layer 45, the liquid crystal layer 46, the alignment layer 47, the transparent electrode 44, the reflective polarizing plate 6 and the substrate 41 are sequentially laminated. Antireflection films 15 and 15 are formed on both surfaces. In addition, the reflective polarizing plates 6 and 6 before and after the modulation element 31 have the spiral directions of the reflective polarizing plates reversed from each other.

  In this image display device, the light beam that has not been modulated by the modulation element 31 passes through the modulation element 31 and is reflected by the reflective polarizing plate 6 to reach the rod integrator 26 or the reflection plate 14c. The light beam reflected by the reflecting plate c becomes counter-twisted circularly polarized light, is reflected by the reflective polarizing plate 6, and reaches the rod integrator 26. This light is made uniform by the rod integrator 26, partly reflected by the reflector 14 provided around the opening at the end on the light source 27 side, and the remaining part that has passed through the opening returns to the light source 27. Recycled light is uniformly illuminated by the rod integrator 26 and uniformly illuminates the modulation element 31 in a state of polarization conversion.

  In this image display device, the liquid crystal mode of the modulation element adopts the VA mode, but a quarter wave plate is disposed between the cholesteric liquid crystal polymer circularly polarizing plate and the liquid crystal layer to convert it into linearly polarized light. Thus, a liquid crystal such as a TN mode using linearly polarized light can be obtained.

Furthermore, as shown in FIG. 43, this image display apparatus can also be configured using three modulation elements 31a, 31b, and 31c. That is, in this image display device, a light source 27 having an elliptical mirror 16, a relay lens 28, a field lens 29, a reflecting plate 14 having an opening, a rod integrator 26, a condenser lens 30, a relay lens 20, a reflecting plate 14c, Condenser lenses 10 are sequentially arranged, and an illumination optical system in which the optical axis of the condenser lens 10 is shifted in parallel to the optical axis of the optical system from the light source 27 to the relay lens 20 is configured, and light emitted from this optical system Is guided to the first spectral reflection mirror 57 through the mirror 56.
In the first spectral reflection mirror 57, for example, R (red) light is transmitted and G (green) light and B (blue) light are reflected. The R (red) light is reflected by the mirror 62, passes through the relay lens 64, passes through the reflective polarizing plate 6, the transmissive modulation element 31 b, and the reflective polarizing plate 6 serving as an analyzer, and reaches the combining prism 66. The G (green) light and B (blue) light reach the second spectral reflection mirror 58, and for example, G (green) light is transmitted and B (blue) light is reflected. The G (green) light passes through the relay lens 60, passes through the reflective polarizing plate 6, the transmissive modulation element 31 a, and the reflective polarizing plate 6 serving as an analyzer, and reaches the combining prism 66. The B (blue) light is reflected by the mirror 63 through the relay lens 61, passes through the relay lens 65, passes through the reflective polarizing plate 6, the transmissive modulation element 31 c, and the reflective polarizing plate 6 serving as an analyzer, The composition prism 66 is reached.

  In the combining prism 66, R (red) light, G (green) light, and B (blue) light are combined and emitted toward a projection lens (not shown). This light is projected onto the screen by the projection lens.

  In each of the above-described embodiments, a liquid crystal modulation element is used as a modulation element, and light modulated by the modulation element is projected onto a screen via a projection lens (not shown). The modulation element is not limited to the liquid crystal modulation element, and other types of modulation elements may be used. In addition, the configuration for improving the recycling efficiency by the structure of the illumination optical system is not limited to the above-described configuration, and any structure that can improve the recycling efficiency by providing a reflection function at the optimum position of the light source may be used.

  As described above, in the present invention, polarization separation / combination can be achieved at low cost by the light source and the illumination device that can efficiently recycle unnecessary light in the projection device. In addition, when using a single-plate modulation element using a color filter, it becomes possible to improve the light utilization efficiency, and even when using a sequential color type single-plate modulation element, the light utilization efficiency can be improved. Is possible. And it becomes possible to improve the light utilization efficiency of a modulation element with a low aperture ratio, and to increase the peak luminance in a dark screen.

It is a block diagram which shows the outline | summary of a structure of the image display apparatus which concerns on this invention. It is a side view which shows the basic optical path in the illuminating device which comprises the said image display apparatus. It is a side view which shows the optical path at the time of tilting the reflective element in the illuminating device which comprises the said image display apparatus. It is a side view which shows the optical path at the time of shifting the one part optical axis of the optical system in the illuminating device which comprises the said image display apparatus. It is a side view which shows the optical path at the time of shifting the one part optical axis of the optical system in the said image display apparatus. It is a longitudinal cross-sectional view which shows the 1st structure of the light source which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 2nd structure of the light source which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 3rd structure of the light source which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 4th structure of the light source which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 5th structure of the light source which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 6th structure of the light source which comprises the said image display apparatus. It is a front view which shows the structure of the quarter wavelength plate in the 6th structure of the said light source. It is a longitudinal cross-sectional view which shows the 1st structure of the illuminating device which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the state which has produced the problem in the light source which comprises the said image display apparatus. It is a side view which shows the optical path in the 1st structure of the illuminating device which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 2nd structure of the illuminating device which comprises the said image display apparatus. It is a front view which shows the structure of the reflecting plate in the 2nd structure of the said illuminating device. It is a front view which shows the state which recycled light returned to the reflecting plate at the time of tilting a reflecting element in the 2nd structure of the said illuminating device. It is a front view which shows the state which recycled light returned to the reflecting plate at the time of inclining a reflective element vertically in the 2nd structure of the said illuminating device. It is a longitudinal cross-sectional view which shows the 3rd structure of the illuminating device which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 4th structure of the illuminating device which comprises the said image display apparatus. It is a longitudinal cross-sectional view which shows the 5th structure of the illuminating device which comprises the said image display apparatus. It is the perspective view (a) and top view (b) which show the structure of the rod integrator in a 5th structure of the said illuminating device, and a reflecting plate. It is a longitudinal cross-sectional view which shows the 6th structure of the illuminating device which comprises the said image display apparatus. It is the longitudinal cross-sectional view (a) and principle figure (b) which show the 1st structure of the said image display apparatus. In the first configuration of the image display device, when the antireflection film is provided on the reflective circularly polarizing plate, the spectral transmittance (A) of the counterclockwise circularly polarized light is provided, and when the antireflection film is provided on the reflective circularly polarizing plate. Spectral transmittance of right-handed circularly polarized light (B), Spectral transmittance of counterclockwise circularly polarized light (C) when no antireflection film is provided on the reflective circularly polarizing plate, and antireflection film provided on the reflective circularly polarizing plate It is a graph which respectively shows the spectral transmittance (D) of clockwise rotation polarized light when there is no. It is a longitudinal cross-sectional view which shows the 2nd structure of the said image display apparatus. It is the longitudinal cross-sectional view (a) and principle figure (b) which show the 3rd structure of the said image display apparatus. It is the longitudinal cross-sectional view (a) which shows the 4th structure of the said image display apparatus, a principle figure (b), and a principal part perspective view (c). It is the longitudinal cross-sectional view (a) and principle figure (b) which show the 5th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the 6th structure of the said image display apparatus. It is the cross-sectional view (a) and principal part perspective view (b) which show the 7th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the 7th structure of the said image display apparatus. It is a principal part longitudinal cross-sectional view which shows the structure of the modulation element in the 7th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the 8th structure of the said image display apparatus. It is a principal part longitudinal cross-sectional view which shows the structure of the modulation element in the 7th structure of the said image display apparatus. It is a side view which shows the structure of the area | region of one pixel of the modulation element in the 7th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the 9th structure of the said image display apparatus. It is the longitudinal cross-sectional view (a) and principal part top view (b) which show the 10th structure of the said image display apparatus. It is the longitudinal cross-sectional view (a) and principal part top view (b) which show the 11th structure of the said image display apparatus. It is a graph which shows the change of the peak intensity | strength of the display image in the 11th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the 12th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the 13th structure of the said image display apparatus. It is a principal part longitudinal cross-sectional view which shows the structure of the modulation element in the 11th and 12th structure of the said image display apparatus. It is a longitudinal cross-sectional view which shows the structure of the conventional image display apparatus. It is a perspective view which shows the manufacture process of the PS conversion element used in an image display apparatus. It is a longitudinal cross-sectional view which shows the 1st structure of the illuminating device in the conventional image display apparatus. It is a longitudinal cross-sectional view which shows the 2nd structure of the illuminating device in the conventional image display apparatus. It is a longitudinal cross-sectional view which shows the 3rd structure of the illuminating device in the conventional image display apparatus.

Explanation of symbols

1, 24, 27 Light source, 2 Fly eye integrator, 3 Polarization conversion element, 4 Condenser lens group, 5, 31 Modulation element, 6 Reflective element, 7 Parabolic mirror, 14 Reflector, 16 Elliptical mirror

Claims (10)

A lighting device having a light source;
A modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image to transmit or reflect;
A projection lens for forming an image of the modulation element;
A first reflecting element that reflects unnecessary light that does not illuminate the modulation element out of the light flux emitted from the illumination device to the light source side;
The light source includes a reflecting mirror having a reflecting surface that reflects light from a light emitting point as a paraboloid, and a protective glass provided on an opening end side of the reflecting mirror. An image display device, wherein a second reflecting element that reflects unnecessary light reflected by the first reflecting element is provided on a surface.   2. The discharge lamp according to claim 1, wherein the light source uses a discharge lamp having a light emitting point in a bulb made of a glass tube and provided with an antireflection film on at least a part of the surface of the glass tube. Image display device.   The image display apparatus according to claim 1, wherein the second reflecting element is formed in a region where the light beam reflected by the reflecting mirror does not pass. A lighting device having a light source;
A modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image to transmit or reflect;
A projection lens for forming an image of the modulation element;
A first reflecting element that reflects unnecessary light that does not illuminate the modulation element out of the light flux emitted from the illumination device to the light source side;
The light source includes a reflecting mirror having a reflecting surface that reflects light from a light emitting point as a spheroidal surface, and a protective glass provided on the opening end side of the reflecting mirror, and either the front or back of the protective glass An image display device, wherein a second reflecting element that reflects unnecessary light reflected by the first reflecting element is provided on a surface. The light emitting point is located at a first focal point of the reflecting mirror;
The second reflecting element is formed in a region where the light beam reflected by the reflecting mirror is not transmitted,
The condensing lens which condenses the light beam reflected by the said reflective element on the 2nd focus of the said reflective mirror in the vicinity of the said 2nd reflective element is provided. Image display device. A lighting device having a light source;
A modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image to transmit or reflect;
A projection lens for forming an image of the modulation element;
A first reflecting element composed of a reflective polarizing plate that reflects unnecessary light that does not illuminate the modulation element to the light source side out of the luminous flux emitted from the illumination device;
The light source includes a reflecting mirror having a reflecting surface that reflects light from a light emitting point as a paraboloid, and a protective glass provided on an opening end side of the reflecting mirror. The surface is provided with a second reflective element that reflects unnecessary light reflected by the first reflective element,
An image display device, wherein a quarter-wave plate is provided between the second reflective element and the first reflective element.   The image display apparatus according to claim 6, wherein the quarter-wave plate and the first reflective element are integrally provided on the protective glass.   7. The image display device according to claim 6, wherein the quarter-wave plate is divided into a plurality of regions radially about the central axis of the reflecting mirror. A lighting device having a light source;
A modulation element that is illuminated by the illumination device and spatially modulates illumination light according to a display image to transmit or reflect;
A projection lens for forming an image of the modulation element;
A first reflecting element composed of a reflective polarizing plate that reflects unnecessary light that does not illuminate the modulation element to the light source side out of the luminous flux emitted from the illumination device;
The light source includes a reflecting mirror having a reflecting surface that reflects light from a light emitting point as a spheroidal surface, and a protective glass provided on the opening end side of the reflecting mirror, and either the front or back of the protective glass The surface is provided with a second reflective element that reflects unnecessary light reflected by the first reflective element,
An image display device comprising a relay lens and a field lens between the ¼ wavelength plate and the first reflecting element.   The image display device according to claim 9, wherein the light emitting point is disposed at the first focal point of the reflecting mirror, and the relay lens is disposed at the second focal point of the reflecting mirror.

Images