JP2006267530A - Illuminator and projection type display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide illuminating technique by which efficiency of utilizing light emitted from a light source is improved. <P>SOLUTION: A relay lens system 6 is constituted so that the emitting surface of a columnar optical device 5 and a surface to be illuminated 15 can have conjugate relation, and includes a first stage lens group 60, a middle lens group 61 including a meniscus lens 61a and a biconvex lens 61b, and a final stage lens 62. The relay lens system 6 is constituted to satisfy 2.45<FNO<2.70, 0.005<f1/f0<0.23, 0.03<f2/f0<0.53, 0.03<f3/f0<0.71 and νp/νn>1.99. Wherein, FNO shows the f-number of the relay lens system 6, f0 to f3 show the focal distances of the relay lens system 6, the first stage lens group 60, the middle lens group 61 and the final stage lens 62, and νn and νp are the Abbe numbers of the meniscus lens 61a and the biconvex lens 61b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an irradiation apparatus and a projection display apparatus using the irradiation apparatus.

  In recent years, projection display devices (projectors) have attracted attention as large screen image display devices. A compact, high-definition and high-luminance CRT projector using a CRT (cathode ray tube), a liquid crystal projector using a liquid crystal panel, a DMD projector using a DMD (Digital Micromirror Device), and the like have been commercialized.

  In addition to projection display devices that only support AV sources such as movies and television programs, the market for projection display devices called data projectors that project computer images is rapidly expanding. Significant performance improvements such as improved contrast, higher resolution, and improved brightness uniformity have been made.

  In particular, projectors using light valves such as liquid crystal panels and DMDs are superior to CRT projectors in that they can improve brightness and resolution independently, and are increasingly applied to projection televisions (rear projection projectors). ing.

  In a conventional illumination optical system in such a projection display device using a light valve, the light valve is arranged in the optical path of a lens system in which the light source and the exit pupil of the projection lens are conjugated. Most of them used a kind of Koehler illumination method that irradiates the bulb with light.

  However, in recent years, in order to improve the illumination uniformity, fly-eye integrator illumination method and rod integrator illumination method are frequently used in the illumination optical system, and a higher level of imaging performance is provided for the illumination optical system. Therefore, an optical system having a complicated configuration has been demanded.

  For example, Patent Document 1 discloses an example of a reflective projector using a rod integrator illumination method. In the reflection type projector of Patent Document 1, the traveling path of light is converted by a critical angle prism, thereby eliminating the deflecting beam splitter and easily aligning the optical axis of the optical system without requiring a long optical length. The effect of becoming. In Patent Document 1, since the rod integrator illumination method using a light mixing means such as a scrambler is adopted, the illumination optical system and the projector are provided with a simplified structure and excellent cost performance. Is possible.

  Patent Document 2 discloses a technique related to a prism used in a projection display device.

Japanese Patent No. 2939237 US Pat. No. 5,604,624

  In general, in order to improve the utilization efficiency of light emitted from a light source and obtain a high-efficiency projection display device, 1) design of an illumination optical system for efficiently irradiating light to a light valve; In particular, it is important to minimize the illumination margin for the effective pixel area of the light valve, and 2) to improve the uniformity of the irradiation light intensity in the effective pixel area of the light valve.

  Here, in the light valve, light is irradiated to a range slightly larger than the effective pixel area, and therefore, a part of the light irradiated to the light valve is lost without being irradiated to the effective pixel area. The above-mentioned irradiation margin means the ratio of the amount of light that becomes the loss to the amount of light that is irradiated to the effective pixel region of the light valve and actually contributes to image display.

  However, the reflection type projector disclosed in Patent Document 1 cannot sufficiently reduce the irradiation margin and cannot sufficiently improve the uniformity of the irradiation light intensity. As a result, the utilization efficiency of the light emitted from the light source is sufficient. May not be improved.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide an illumination device capable of improving the utilization efficiency of light emitted from a light source and a projection display device using the illumination device. To do.

  The illumination device of the present invention includes a light source, a converging unit that converges light emitted from the light source, an optical element that emits light converged by the converging unit while reducing nonuniformity in intensity distribution, and the optical device. An image formed on the exit surface of the element is transmitted to the surface to be illuminated, and the relay lens system is configured such that the exit surface and the surface to be illuminated have a conjugate relationship. The first stage lens group having a positive refractive power to which the outgoing light from the optical element is incident, the negative lens to which the outgoing light from the first stage lens group is incident, and the outgoing light from the negative lens are incident An intermediate lens group having a positive refractive power as a whole, and a final lens having a positive refractive power to which light emitted from the positive lens is incident. Light emitted from the last lens is irradiated Is, the relay lens system is configured so as to satisfy the following equation (1) to (5).

2.45 <FNO <2.70 (1)
0.005 <f1 / f0 <0.23 (2)
0.03 <f2 / f0 <0.53 (3)
0.03 <f3 / f0 <0.71 (4)
νp / νn> 1.99 (5)
However,
FNO: F number of the relay lens system f0: Focal length of the relay lens system f1: Focal length of the first lens group f2: Focal distance of the intermediate lens group f3: Focal length of the final lens νn: Negative Abbe number of lens νp: Abbe number of the positive lens

  According to the illumination device of the present invention, since the relay lens system is configured to satisfy the expressions (1) to (5), lateral chromatic aberration, spherical aberration, and distortion are reduced on the illuminated surface. Therefore, it is possible to irradiate the surface to be illuminated with light with reduced loss light, improve the uniformity of the light irradiation intensity on the surface to be illuminated, and improve the light use efficiency.

  Furthermore, since the F-number FNO of the relay lens system satisfies the formula (1), the irradiation device is suitable for a projection display device having a reflective light valve with an inclination angle of ± 12 degrees in the on / off state of the movable mirror. Can provide.

Embodiment 1 FIG.
FIG. 1 is a side view showing a configuration of illumination apparatus 10 according to Embodiment 1 of the present invention. In FIG. 1, the reflector 2 has a cross-sectional structure in order to show its internal structure. The illumination device 10 according to the first embodiment is used as an illumination optical system that irradiates light to the light valve in a projection display device having a light valve.

  As shown in FIG. 1, an illumination device 10 according to the first embodiment is an illumination device that irradiates light to an illuminated surface 150 on which a light valve of a projection display device is disposed. A focusing unit 4 that focuses the light emitted from the light source 1, a columnar optical element 5 that emits the light collected by the focusing unit 4 while reducing the nonuniformity of its intensity distribution, and an exit surface of the columnar optical element 5 And a relay lens system 6 that transmits an image to be formed to the illuminated surface 150, and these are linearly arranged on the illumination optical axis 200.

  The light source 1 includes a light emitter that emits white light, monochromatic light, or the like. The converging unit 4 includes a reflector 2 and a condenser lens system 3. The reflector 2 is, for example, a rotary parabolic mirror, and the light source 1 is disposed in the vicinity of the focal point thereof. As a result, the light emitted from the light source 1 is substantially collimated by the reflector 2 and enters the condenser lens system 3. The condenser lens system 3 includes a plano-convex lens 3a and a meniscus lens 3b. The condenser lens system 3 focuses the light substantially parallelized by the reflector 2 to form an image of the light source 1. From the viewpoint of improving the light utilization efficiency, it is preferable to arrange the light incident surface of the columnar optical element 5 at the position where the image of the light source 1 is formed. Further, the image size and angular distribution (light distribution around the illumination optical axis 200) of the light source 1 can be brought close to a predetermined value by adjusting the performance of the condenser lens system 3.

  In the first embodiment, a discharge lamp having an electrode gap length of about 1.3 mm is employed as the light source 1, and a reflector 2 having a rotating paraboloid having a focal length of 7.5 mm is used. An image of the light source 1 having an effective diameter of about 4 mm is formed by the condenser lens system 3.

  The light source 1 is preferably a metal halide lamp, an ultra-high pressure mercury lamp, or the like having a small light emitting region size and high luminous efficiency. This is because it is easier for the reflector 2 to collimate the light when the size of the light emitting region in the light source 1 is smaller, and this makes it easier for the condenser lens system 3 to collect the light on the incident surface of the columnar optical element 5. This is because the light collection efficiency can be increased.

  Alternatively, the reflector 2 may be a spheroid mirror, the light source 1 may be disposed in the vicinity of the first focal point of the spheroid mirror, and the light emitted from the light source 1 may be focused only by the reflector 2. In this case, the condenser lens system 3 is not necessary, and the converging unit 4 is configured only by the reflector 2.

  The columnar optical element 5 relaxes the non-uniformity of the intensity distribution of the light focused by the converging unit 4, forms a new image of the light source 1 on its exit surface, and a secondary light source surface on the exit surface. Form.

  The relay lens system 6 is configured such that the exit surface of the columnar optical element 5 and the illuminated surface 150 are in a conjugate relationship, and an image formed on the exit surface of the columnar optical element 5 is transmitted to the illuminated surface 150. To do. Since a secondary light source surface with reduced luminance non-uniformity is formed on the exit surface of the columnar optical element 5, light emitted from the light source surface is imaged again on the illuminated surface 150 by the relay lens system 6. By doing so, efficient and uniform irradiation becomes possible.

  As shown in FIG. 1, the relay lens system 6 is configured such that the principal ray 100 of the irradiation light beam on the illuminated surface 150 is substantially parallel to the illumination optical axis 200, and is telecentric on the image side. The optical system is configured. In the telecentric optical system, it is easy in design to increase the peripheral light amount ratio, so that the image formed on the exit surface of the columnar optical element 5 is transmitted to the illuminated surface 150 while maintaining the uniformity of the light intensity. It is possible to illuminate a light bulb with high efficiency and high quality.

  The dimension of the exit surface of the columnar optical element 5 is determined based on the imaging magnification of the relay lens system 6 and the size of the illuminated surface 150. In order to improve the light utilization efficiency, the shape of the exit surface of the columnar optical element 5 is preferably substantially similar to the shape of the illuminated surface 150, that is, the shape of the effective pixel region of the light valve.

  Next, the detailed structure of the columnar optical element 5 will be described. FIG. 2 is a side sectional view showing an example of the structure of the columnar optical element 5. The columnar optical element 5 shown in FIG. 2 is formed of a glass rod, and the light incident surface 5a and the light exit surface 5b have the same shape. When the light 110 collected by the converging unit 4 is incident on the incident surface 5a of the columnar optical element 5, the light 110 undergoes total reflection at the interface between the outer surface 5c of the columnar optical element 5 and the outside air. As shown in FIG. 2, the columnar optical element 5 repeats this total reflection. Thereby, the light 110 is efficiently transmitted to the exit surface 5b of the columnar optical element 5, and the nonuniformity of the intensity distribution of the light 110 generated on the entrance surface 5a is reduced, and the intensity distribution on the exit surface 5b is reduced. A light source surface with very high uniformity is formed.

  The flatness of all surfaces constituting the columnar optical element 5, the parallelism between the incident surface 5 a and the exit surface 5 b, or the parallelism between the outer surfaces 5 c is a general plane as a material of the columnar optical element 5. Even when a glass member is used, the glass member is maintained to such an extent that it hardly affects the formation of the secondary light source surface formed on the emission surface 5b.

  In addition, when the incident surface 5a is disposed at a position where the light emitted from the light source 1 is collected by the converging unit 4, the light transmission efficiency is the highest. In this case, since the energy density of the incident light to the columnar optical element 5 is increased, the heat resistance of the columnar optical element 5 is improved. In addition, the shapes and dimensions of the incident surface 5a and the exit surface 5b of the columnar optical element 5 may be different from each other.

  FIG. 3 is a side sectional view showing another example of the structure of the columnar optical element 5. The columnar optical element 5 shown in FIG. 3 is a hollow rod provided with a hollow base material 15 and a reflector 16 provided on the inner surface of the base material 15. The inner surface of the base material 15 is formed so that four planes surround a predetermined space, and the reflecting material 16 is provided on each of the four planes. Each of the entrance surface 5 a and the exit surface 5 b of the columnar optical element 5 is provided with a rectangular opening surrounded by the reflecting material 16. A circular opening may be provided on the incident surface 5a, and a square opening may be provided on the outgoing surface 5b.

  As shown in FIG. 3, the light 110 that has entered the columnar optical element 5 from the incident surface 5 a is repeatedly reflected by the reflector 16 and travels through the columnar optical element 5. Thereby, a secondary optical surface having a uniform intensity distribution is formed on the emission surface 5b.

Since the columnar optical element 5 using the reflecting material 16 as shown in FIG. 3 causes a loss of light in the reflecting material 16, the columnar optical element 5 formed of a glass rod as shown in FIG. In general, the light utilization efficiency decreases. However, in the columnar optical element 5 of FIG. 3, for example, high-purity aluminum is vacuum-deposited on a base material that is anodized on the surface of an aluminum material, and a silicon oxide film (SiO ₂ film) as a protective layer thereon Further, the columnar optical element 5 having excellent reflection characteristics, heat resistance and weather resistance can be realized by depositing and forming a titanium oxide film (TiO ₂ film) or the like. The columnar optical element 5 is preferably formed using MIRO (registered trademark) manufactured by Allanod.

  Since the columnar optical element 5 shown in FIG. 3 is formed of two materials, that is, a base material 15 and a reflective material 16, light reflection can be achieved by individually selecting the material of the base material 15 and the reflective material 16. The heat dissipation characteristics can be improved while maintaining the characteristics. For example, the heat dissipation characteristics can be improved while maintaining the reflection characteristics by forming the base material 15 with a metal having an excellent heat dissipation effect. Therefore, in order to increase the light use efficiency, the incident surface 5a is disposed at the light converging point by the condenser lens system 3, and even if the energy density of the incident light to the columnar optical element 5 is increased, the light is reflected. Heat generation in the columnar optical element 5 due to incident light can be suppressed while maintaining the characteristics.

  Further, since the columnar optical element 5 shown in FIG. 2 is formed of a single material, the member that holds the columnar optical element 5 from the outside does not affect the light reflection characteristics. It is necessary to devise the material and shape of the member. However, in the columnar optical element 5 of FIG. 3, since the reflecting material 16 is provided on the inner surface of the hollow base material 15, the influence of the member that holds the columnar optical element 5 from the outside on the light reflection characteristics is not affected. Few. Therefore, the columnar optical element 5 can be held by simple means, and the manufacturing cost of the illumination device 10 can be reduced. Furthermore, since the hollow base material 15 can be formed by bending a plate-like member, the columnar optical element 5 can be formed by a simple manufacturing method.

  Next, the detailed structure of the relay lens system 6 will be described with reference to FIG. As shown in FIG. 1, the relay lens system 6 includes a first-stage lens group 60 having a positive refractive power, an intermediate lens group 61 having a positive refractive power, and a final-stage lens 62 having a positive refractive power. It has. The first lens group 60 includes a meniscus lens 60a and a plano-convex lens 60b both having positive refractive power. The intermediate lens group 61 includes a meniscus lens 61a having a negative refractive power and a biconvex lens 61b having a positive refractive power, and has a positive refractive power as a whole. The meniscus lens 61a and the biconvex lens 61b are bonded to each other with a balsam. The last stage lens 62 is a plano-convex lens.

  The meniscus lens 60a, the plano-convex lens 60b, the meniscus lens 61a, the biconvex lens 61b, and the final stage lens 62 are arranged in a line in this order between the columnar optical element 5 and the illuminated surface 150. The meniscus lens 60a is arranged with its concave surface, the plano-convex lens 60b with its flat surface, the meniscus lens 61a with its convex surface, and the final lens 62 with its convex surface facing the columnar optical element 5 side.

  In the first embodiment, the meniscus lens 61a and the biconvex lens 61b are formed of different glass materials. In the plurality of lenses included in the relay lens system 6, the meniscus lens 61a, the biconvex lens 61b, and the other lenses are formed of different glass materials, and the lenses other than the meniscus lens 61a and the biconvex lens 61b. Are made of the same glass material.

  In the plurality of lenses included in the relay lens system 6, the meniscus lens 61a and other lenses may be formed of different glass materials, and the lenses other than the meniscus lens 61a may be formed of the same glass material. .

  The last-stage lens 62 disposed immediately before the illumination target surface 150 has a smaller refractive power than the biconvex lens 61 b of the intermediate lens group 61. By the action of the final stage lens 62, the principal ray 100 of the illumination light beam incident on the illumination target surface 150 becomes substantially parallel to the illumination optical axis 200, thereby realizing telecentric illumination. At this time, when the intermediate lens group 61 is composed only of a lens having a positive refractive power, it is difficult to correct off-axis aberrations, particularly distortion aberration and lateral chromatic aberration, of the final lens 62. Therefore, in the first embodiment, a negative lens, that is, a meniscus lens 61a is arranged in the intermediate lens group 61, thereby reducing the off-axis aberration of the final stage lens 62.

  In the first embodiment, a stop 63 is provided on the entrance surface of the meniscus lens 61 a of the intermediate lens group 61, and the relay lens system 6 that forms an image of the light source 1 in the vicinity of the stop 63 is used. Thereby, the distortion aberration of the meniscus lens 61a is reduced.

  Since the exit surface 5b of the columnar optical element 5 serves as an illumination light source, in order to improve the illumination efficiency, aberrations at a relatively high position in the image of the light source 1, that is, off-axis such as distortion aberration and lateral chromatic aberration, etc. It is necessary to correct aberrations with priority.

  In the first embodiment, the off-axis aberration is satisfactorily corrected by providing a negative lens in the intermediate lens group 61 or by providing the stop 63, so that the irradiation margin on the illuminated surface 150 is reduced. And the light utilization efficiency can be improved.

  In particular, since the lateral chromatic aberration is corrected by providing a negative lens in the intermediate lens group 61, it is effective when the illumination device 10 is used in a projection display device capable of color display. In other words, when the light emitted from the light source 1 is passed through the color filter, three color lights of RGB are generated, but the slightly colored region generated because the three color lights do not overlap with the illuminated surface 150 is corrected for the chromatic aberration of magnification. By doing so, high-quality white illumination is possible over the entire surface 150 to be illuminated. This feature is because a single-plate projector that performs color display with a single light valve has a common optical path for the three color lights of RGB, so that it can be used for multiple-plate projectors that can correct aberrations for each color light. The effect is more pronounced when it is used in the single-plate projector.

  In the first embodiment, the relay lens system 6 is configured to satisfy the following expressions (1) to (5) based on the simulation result.

2.45 <FNO <2.70 (1)
0.005 <f1 / f0 <0.23 (2)
0.03 <f2 / f0 <0.53 (3)
0.03 <f3 / f0 <0.71 (4)
νp / νn> 1.99 (5)
Where FNO is the F number of the relay lens system 6, f0 is the focal length of the relay lens system 6, f1 is the focal length of the first lens group 60, f2 is the focal distance of the intermediate lens group 61, and f3 is the final lens 62. The focal length, νn represents the Abbe number of the negative meniscus lens 61a, and νp represents the Abbe number of the positive biconvex lens 61b.

  In this simulation, spherical aberration, distortion, lateral chromatic aberration, astigmatism, curvature of field aberration, and coma aberration are considered as aberrations generated on the illuminated surface 150, and the size of the image on the illuminated surface 150, light Is performed in consideration of the angle of the light when entering the illuminated surface 150.

  When the relay lens system 6 is configured so that the F-number FNO satisfies the expression (1), a projection type using a reflection type light valve having an inclination angle of ± 12 ° in the on / off state as in the current DMD. An irradiation device suitable for a display device can be provided. That is, when the illumination device 10 according to the first embodiment is incorporated as a lighting device for the reflection type light valve in a projection type display device using a reflection type light valve having an inclination angle of ± 12 °, a projected image with good image quality. Is obtained.

  Further, in the relay lens system 6 configured to satisfy Expression (1), if each lens of the intermediate lens group 61 is formed of a material that satisfies Expression (5), the magnification on the illuminated surface 150 is increased. Chromatic aberration can be reduced. Therefore, an image formed on the exit surface of the columnar optical element 5 can be efficiently transmitted onto the illuminated surface 150. In addition, since the chromatic aberration of magnification can be corrected satisfactorily, when the illumination device 10 is used in a projection display device capable of color display, the three color lights of RGB are irradiated on the illuminated surface 150 as described above. It is possible to reduce the slightly colored areas that occur because they do not overlap.

  Further, in the relay lens system 6 designed to satisfy the expressions (1) and (5), when f0 to f3 are set so as to satisfy the expressions (2) to (4), Spherical aberration and distortion can be reduced.

  As described above, the spherical aberration, the distortion aberration, and the lateral chromatic aberration can be reduced by designing the relay lens system 6 so as to satisfy the expressions (1) to (5). Accordingly, the irradiation margin is reduced, and it becomes possible to irradiate the illuminated surface 150 with light with reduced loss light, and the uniformity of the illumination intensity of the light on the illuminated surface 150 is improved. As a result, the light utilization efficiency is improved.

  Note that f1 / f0 is set to 0.23 or more shown in the equation (2), f2 / f0 is set to 0.53 or more shown in the equation (3), and f3 / f0 is shown in the equation (4). If it is set to 0.71 or more, the distance between the principal points of the lenses constituting the relay lens system 6 tends to increase, and the total length of the relay lens system 6 tends to increase.

  Further, by reducing the values of f1 to f3, f1 / f0 is set to 0.005 or less shown in the equation (2), f2 / f0 is set to 0.03 or less shown in the equation (3), If f3 / f0 is set to 0.03 or less shown in the equation (4), the effective diameter of each lens constituting the relay lens system 6 increases, so that the illumination device 10 becomes large, saving space and reducing costs. It becomes difficult to realize.

  In the first embodiment, the meniscus lens 61a and the biconvex lens 61b are bonded to each other by a balsam, so the lateral chromatic aberration on the illuminated surface 150 is further reduced, and the light utilization efficiency is further improved.

  Next, a design example of the relay lens system 6 will be described. FIG. 4 is a diagram showing a design example of the relay lens system 6. RED in the figure indicates the paraxial magnification in the relay lens system 6. In addition, i in the figure indicates an optical surface existing between the secondary light source surface and the illuminated surface 150 formed on the exit surface 5b of the columnar optical element 5, and the secondary surface. A serial number from 0 is assigned to the surface 150 to be illuminated from a typical light source surface. That is, the numbers from 0 to 10 indicated by i are the secondary light source surface, the concave surface of the meniscus lens 60a, its convex surface, the plane of the plano-convex lens 60b, its convex surface, the convex surface of the meniscus lens 61a, and the light source 1 side of the biconvex lens 61b. , The convex surface of the illuminated surface 150 side, the convex surface of the final lens 62, its flat surface, and the illuminated surface 150 are shown.

  In the drawing, Ri represents the radius of curvature of the i-th optical surface, and Di represents the distance between the i-th to (i + 1) -th optical surfaces. Further, nd in the figure indicates the refractive index with respect to the d-line in the lens including the optical surface indicated by the number i corresponding thereto, and νd in the figure indicates the Abbe of the lens including the optical surface indicated by the number i corresponding thereto. Shows the number. Therefore, for example, nd = 1.5168 corresponding to i = 1 in the figure indicates the refractive index with respect to the d-line of the meniscus lens 60a, and νd = 27.5 corresponding to i = 5 is the Abbe of the meniscus lens 61a. Shows the number. Ri = ∞ represents a plane, and the unit of the values of f0 to f3 and Ri and Di is “mm”.

When f1 / f0, f2 / f0, f3 / f0, and νp / νn are obtained from the design example shown in FIG.
f1 / f0 = 0.04
f2 / f0 = 0.10
f3 / f0 = 0.16
νp / νn = 2.23
Thus, the expressions (2) to (5) are satisfied. In this design example, since FNO = 2.60, Expression (1) is also satisfied.

  In the design example of FIG. 4, among the five lenses constituting the relay lens system 6, the negative meniscus lens 61 a, that is, the lens showing the refractive index nd = 1.7552, uses HOYA E-FD4. As the biconvex lens 61b, that is, the lens showing the refractive index nd = 1.5891, BACD5 manufactured by HOYA is used. As other lenses, that is, lenses having a refractive index nd = 1.5168, an inexpensive BSC7 manufactured by HOYA is used. Further, the manufacturing cost is reduced by configuring all optical action surfaces (optical surfaces) in the relay lens system 6 as spherical surfaces.

  In the relay lens system 6 according to the first embodiment, the meniscus lens 61a and the biconvex lens 61b are bonded to each other with a balsam. However, in order to reduce the manufacturing cost, they are arranged without being bonded to each other. May be. A design example of the relay lens system 6 in this case is shown in FIG. In the present design example, the meniscus lens 61a and the biconvex lens 61b are arranged apart from each other, so that one more optical surface exists in the relay lens system 6 than in the design example of FIG. Therefore, the number indicated by i increases by one. That is, the numbers from 0 to 11 indicated by i are the secondary light source surface, the concave surface of the meniscus lens 60a, its convex surface, the plane of the plano-convex lens 60b, its convex surface, the convex surface of the meniscus lens 61a, its concave surface, and the biconvex lens 61b. The convex surface on the light source 1 side, the convex surface on the illuminated surface 150 side, the convex surface of the last-stage lens 62, the flat surface, and the illuminated surface 150 are shown.

When f1 / f0, f2 / f0, f3 / f0, and νp / νn are obtained from the design example shown in FIG.
f1 / f0 = 0.02
f2 / f0 = 0.04
f3 / f0 = 0.05
νp / νn = 2.23
Thus, the expressions (2) to (5) are satisfied. In this design example, since FNO = 2.60, Expression (1) is also satisfied.

  The biconvex lens 61b is formed of the same inexpensive glass material as the meniscus lens 60a, the plano-convex lens 60b, and the final stage lens 62, whereby the manufacturing cost can be further reduced.

  Further, it is possible to configure the first lens group 60 with one aspherical lens while maintaining the optical performance of the relay lens system 6 according to the first embodiment. That is, regarding the first-stage lens group 60, although the term “group” generally means a plurality is used, the first-stage lens group 60 is not limited to being configured by a plurality of lenses. In some cases, a single lens is used.

  In the first embodiment, the optical path from the light source 1 to the illumination target surface 150 is linear. However, as shown in FIG. 6, for example, a reflection mirror or the like is provided immediately after the intermediate lens group 61. An optical path deflecting member 64 may be provided, and the entire optical path may be bent halfway. In this case, a compact lighting device can be realized.

  The optical path deflecting member 64 may be constituted by a dichroic mirror. In this case, among the light of various wavelengths included in the light incident on the optical path deflecting member 64, the light having an unnecessary wavelength such as ultraviolet light is transmitted, and only the light having the required wavelength is reflected to be illuminated 150. Can be irradiated. As a result, the illumination performance for the illuminated surface 150 is improved.

Embodiment 2. FIG.
FIG. 7 is a side view showing the configuration of the projection display apparatus according to Embodiment 2 of the present invention. In FIG. 7, as in FIG. 1, the reflector 2 has a cross-sectional structure to show its internal structure. The projection display device according to the second embodiment is a display device that includes the illumination device 10 according to the above-described first embodiment as an illumination optical system.

  As shown in FIG. 7, the projection display device according to the second embodiment includes the illumination device 10 according to the first embodiment, a rotating color filter 80, a prism 81, a projection optical system 82, and a reflection type. A light valve 83 and a screen 84 are provided.

  The rotating color filter 80 is disposed between the emission surface 5b of the columnar optical element 5 and the meniscus lens 60a so that the optical filter region is adjacent to the emission surface 5b. The optical filter region 80a of the rotating color filter 80 is composed of three regions corresponding to RGB components. For example, the optical filter region 80a rotates in synchronization with a synchronization signal included in the video signal, and the incident region of the light from the columnar optical element 5 is sequentially switched between three regions corresponding to the RGB components. Thereby, in the rotating color filter 80, each color component is extracted from the incident light and emitted. As a result, it is possible to colorize the projected image in a field sequential manner.

  The reflective light valve 83 is a DMD, and includes a plurality of minute movable mirrors 83a arranged in a matrix corresponding to a plurality of pixels on the screen 84, and incident light is incident on the plurality of movable mirrors 83a. To reflect. FIG. 8 is a side view showing the operation of the plurality of movable mirrors 83 a included in the reflective light valve 83. 8A and 8B show the movable mirror 83a in a non-movable state and a movable state, respectively.

  As shown in FIG. 8A, in the non-movable state, the light reflecting surfaces 83aa of the plurality of movable mirrors 83a are located on the same plane and are arranged on the illuminated surface 150. As shown in FIG. 8 (b), in the movable state, each of the plurality of movable mirrors 83a rotates and tilts in a predetermined direction or in the opposite direction. Thereby, each of the plurality of movable mirrors 83a is turned on or off. In the reflective light valve 83 according to the second embodiment, the inclination angle α of the movable mirror 83a is set to ± 12 degrees.

  As shown in FIG. 8B, the incident light 120a on the movable mirror 83a in the ON state is reflected by the movable mirror 83a to become reflected light 120b, and the screen 84 passes through the prism 81 and the projection optical system 82. Is incident on. On the other hand, the incident light 120c to the movable mirror 83a in the off state is reflected by the movable mirror 83a, becomes reflected light 120d, and enters a light absorbing member (not shown).

  The reflective light valve 83 individually controls the on / off states of the plurality of movable mirrors 83a based on the input image information, and individually changes the inclinations of the plurality of movable mirrors 83a. . Thereby, the reflection direction of the incident light changes in units of the movable mirror 83a, and the incident light is given two-dimensional modulation based on the image information.

  The prism 81 is disposed immediately after the final lens 62 of the relay lens system 6, and has a light incident surface 81 a perpendicular to the illumination optical axis 200 and a plurality of movable mirrors in a non-movable state in the reflective light valve 83. And a light emitting surface 81b parallel to the plane formed by 83a. The illumination light emitted from the final lens 62 enters the prism 81 from the light incident surface 81a, and the incident illumination light is deflected by the total reflection action inside the prism 81. The deflected illumination light exits from the light exit surface 81 b and enters the reflective light valve 83.

  The prism 81 transmits the light reflected by the movable mirror 83a in the on state in the reflective light valve 83 as it is without being deflected, and enters the projection optical system 82. Thereby, the illumination performance of the illumination optical system, that is, the illumination device 10 and the projection performance of the projection optical system 82 can be made compatible. Furthermore, the illumination optical axis 200 and the projection optical axis 210 that is the optical axis in the projection optical system 82 are separated from each other, and physical interference of the optical system before and after the reflective light valve 83 can be avoided.

  Note that a prism that performs the same operation as the prism 81 according to the second embodiment is disclosed in, for example, Patent Document 2 described above.

  In addition, the light modulation action in the reflective light valve 83 is highly consistent with the interference avoidance action of the optical system in the prism 81, thereby constituting the projection display device according to the second embodiment in a very small space. can do.

  The projection optical system 82 includes a projection lens and the like, and enlarges and projects the light incident from the reflective light valve 83 via the prism 81 onto the screen 84. As a result, a large screen image is displayed on the screen 84.

  As described above, since the illumination device 10 according to the first embodiment can perform highly efficient and uniform illumination, the illumination device 10 like the projection display device according to the second embodiment. By using 10 as an illumination optical system, it is possible to realize a compact and inexpensive projection display apparatus with very high light utilization efficiency and to obtain a bright projection image. This effect can be obtained regardless of projection methods such as front projection and rear projection.

  In addition, in the illuminating device 10 shown in FIG. 7, similarly to the illuminating device 10 shown in FIG. 6, an optical path deflecting member 64 such as a reflection mirror may be further provided to bend the optical path in the illumination optical system. In this case, the projection display apparatus is further compacted, and a small and lightweight projection display apparatus can be realized.

  In the second embodiment, the optical filter region 80a of the rotating color filter 80 is disposed adjacent to the emission surface 5b of the columnar optical element 5, and the optical filter region 80a is disposed between the columnar optical element 5 and the condenser lens. You may arrange | position adjacent to the entrance plane 5a of the said columnar optical element 5 between the systems 3. FIG. Usually, since the light beam diameter is small in the vicinity of the incident surface 5a and the exit surface 5b of the columnar optical element 5, the optical filter region 80a of the rotating color filter 80 is disposed adjacent to the entrance surface 5a or the exit surface 5b of the columnar optical element 5. By doing so, the optical filter region 80a can be reduced. Accordingly, the rotating color filter 80 can be downsized, and a small and lightweight projection display device can be provided.

  In addition to the rotating color filter 80, the projection image may be colored as long as it is a colorization means that can provide a projection display device that is well matched with the illumination device 10 and has high light utilization efficiency. It is possible.

It is a side view which shows the structure of the illuminating device which concerns on Embodiment 1 of this invention. It is a sectional side view which shows the structure of the columnar optical element which concerns on Embodiment 1 of this invention. It is a sectional side view which shows the structure of the modification of the columnar optical element which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a design of the relay lens system which concerns on Embodiment 1 of this invention. It is a figure which shows the example of a design of the relay lens system which concerns on Embodiment 1 of this invention. It is a side view which shows the structure of the modification of the illuminating device which concerns on Embodiment 1 of this invention. It is a side view which shows the structure of the projection type display apparatus which concerns on Embodiment 2 of this invention. It is a side view which shows operation | movement of the movable mirror of the reflection type light valve which concerns on Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source, 4 Focusing part, 5 Columnar optical element, 5a Incidence surface, 5b Output surface, 6 Relay lens system, 10 Illumination device, 15 Base material, 16 Reflective material, 60 First stage lens group, 61 Intermediate lens group, 61a Meniscus Lens, 61b Biconvex lens, 62 Final lens, 64 Optical path deflecting member, 80 Color filter, 80a Optical filter area, 82 Projection optical system, 83 Reflective light valve, 83a Movable mirror, 84 screen, 120b Reflected light, 150 Illuminated Plane, α tilt angle.

Claims (7)

A light source;
A focusing section for focusing the light emitted from the light source;
An optical element that emits light focused by the converging unit while mitigating nonuniformity of its intensity distribution;
A relay lens system configured to transmit an image formed on the exit surface of the optical element to the illuminated surface, and to have a conjugate relationship between the exit surface and the illuminated surface;
The relay lens system is
A first-stage lens group having a positive refractive power into which light emitted from the optical element is incident;
An intermediate lens group having a positive refracting power as a whole, including a negative lens to which the outgoing light from the first stage lens group is incident and a positive lens to which the outgoing light from the negative lens is incident;
A final stage lens having a positive refractive power on which light emitted from the positive lens is incident,
The illuminated surface is irradiated with light emitted from the last lens,
The relay lens system is an illumination device configured to satisfy the following expressions (1) to (5).
2.45 <FNO <2.70 (1)
0.005 <f1 / f0 <0.23 (2)
0.03 <f2 / f0 <0.53 (3)
0.03 <f3 / f0 <0.71 (4)
νp / νn> 1.99 (5)
However,
FNO: F number of the relay lens system f0: Focal length of the relay lens system f1: Focal length of the first lens group f2: Focal distance of the intermediate lens group f3: Focal length of the final lens νn: Negative Abbe number of lens νp: Abbe number of the positive lens The lighting device according to claim 1,
The illumination device, wherein the negative lens and the positive lens are bonded to each other with a balsam. It is an illuminating device as described in any one of Claim 1 and Claim 2, Comprising:
The relay lens system further includes an optical path deflecting member positioned immediately after the intermediate lens group. The lighting device according to claim 3,
The illumination device, wherein the optical path deflecting member is constituted by a dichroic mirror. It is an illuminating device as described in any one of Claim 1 thru | or 4, Comprising:
The said optical element is an illuminating device which has a hollow base material and the reflecting material provided in the inner surface of the said base material. The lighting device according to any one of claims 1 to 5,
A reflective light valve having a plurality of movable mirrors disposed on the illuminated surface, wherein the movable mirror has an on / off state inclination angle of ± 12 degrees; and the movable mirror in the on state in the reflective light valve A projection display device comprising a projection optical system that projects light reflected by the projector onto a screen. The projection display device according to claim 6,
A projection display apparatus, further comprising a color filter in which an optical filter region is disposed adjacent to an incident surface or an output surface of the optical element.

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