JP2008046479A - Lighting optical system and projection type image display device provided therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lighting optical system with a compact constitution where, even if a reflection mirror having a wide condensing angle is used in each light source section, the incidence angle, the condensing position, the condensing angle or the like of a luminous flux made incident on a rod integrator from each light source section can be properly set, and the degree of illumination can be increased. <P>SOLUTION: A condensing state changing means 3A composed of two prisms 30A, 30B is provided between two light source sections 2A, 2B and the rod integrator 4. Optical fluxes made incident on the prisms 30A, 30B from the light source sections 2A, 2B are made incident on the incidence plane 4a of the rod integrator 4 in such a manner that the condensing positions thereof are located in the vicinity of the incidence plane of the rod integrator 4, and also, in a state where the condensing angles are made narrower than those before the incidence. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an illumination optical system for uniformly illuminating an irradiation surface, and a projection-type image display device that modulates output light from the illumination optical system in accordance with predetermined video information using a light valve and projects it onto a screen. Specifically, the present invention relates to a configuration of an illumination optical system including a plurality of light source units.

  2. Description of the Related Art Conventionally, in an illumination optical system used for a projection type image display apparatus, those described in Patent Documents 1 and 2 below are known as having a plurality of light source units for brightly illuminating a screen.

  The device described in Patent Document 1 includes a plurality of light source units that collect and output a light beam from a light source with an ellipsoidal mirror, and the light beam from each light source unit is transmitted to two fly through mirror elements. It is configured to be incident on an integrator unit made of an eye or the like.

  On the other hand, the device described in Patent Document 2 includes a plurality of light source units that collect and output a light beam from a light source by a concave mirror, and directly or directly from each light source unit, a mirror surface, a prism outer surface, or the like. It is configured to enter the rod integrator through the light reflecting surface.

JP 2002-31850 A Japanese Patent No. 3715295

  In recent years, in this type of illumination optical system, in particular, an illumination optical system using a rod integrator, there is a demand to increase illumination illuminance while having a compact configuration.

  In order to meet such a demand, in each light source unit, a reflecting mirror having a large condensing angle (in this specification, an angle formed by the axis of the light beam to be condensed and the outermost light beam) is provided. It is possible to use it. Such a reflecting mirror has an advantage that the light collection efficiency of each light source unit can be increased and the light source unit can be made compact.

  On the other hand, in order to increase the illumination illuminance, it is also important to efficiently guide the emitted light beam from the rod integrator to the light valve while suppressing the light amount loss of the light beam incident on the rod integrator. In order to suppress the loss of light quantity of the light beam incident on the rod integrator, the incident angle of the light beam incident on the rod integrator (incident angle of the axial light beam) is reduced, or the condensing point of the light beam is located near the incident surface. It is desirable to set as follows.

  Also, if the collection angle of the light beam incident on the rod integrator increases, the spread angle of the light beam emitted from the rod integrator increases, making it difficult to efficiently guide the light beam to the light valve. From the viewpoint of suppressing the loss of light quantity of the emitted light beam, it is desirable to reduce the condensing angle of the light beam incident on the rod integrator.

  In this way, in order to increase the illumination illuminance while having a compact configuration, the light collection efficiency in each light source unit, the incident angle and the light collection position of the light beam incident on the rod integrator from each light source unit, the light collection angle, etc. It is important to set them appropriately. However, as in the prior art, these can be changed by changing the shape of the reflecting mirror of each light source unit, and the position of each light source unit and the rod integrator and the reflecting member disposed between them. Achieving by coordination is extremely difficult.

  In addition, in the above-mentioned patent document 2, it is described that the spread angle of the light beam emitted from the rod integrator is controlled by using a rod integrator having a tapered side surface. The rod integrator not only increases the manufacturing cost, but also may cause problems in terms of manufacturing accuracy and mounting accuracy.

  The present invention has been made in view of such circumstances, and even when a reflector having a large condensing angle is used in each light source unit, the incident angle and condensing position of the light beam incident on the rod integrator from each light source unit and An object of the present invention is to provide an illumination optical system and a projection-type image display device that can appropriately set a condensing angle and the like, and can increase illumination illuminance while having a compact configuration.

An illumination optical system according to the present invention includes a plurality of light source units that collect and output a light beam from a light source, and a rod integrator that achieves uniform light quantity of the light beam from the plurality of light source units. A system,
A condensing state in which a light beam incident from each of the plurality of light source units is diverted between the plurality of light source units and the rod integrator, and a condensing position of the light beam is moved forward in a traveling direction of the light beam. A changing means is arranged.

  In the illumination optical system of the present invention, the condensing state changing unit includes a prism that transmits the light beam from the light source unit, and the prism includes an incident surface on which the light beam from the light source unit is incident and the incident light beam. Is preferably provided with at least one reflecting surface for reflecting the light beam in the prism to change the light beam and an exit surface for emitting the light beam.

  In addition, the light source unit may include an ellipsoidal mirror in which one focal point is located in the vicinity of the light emission center of the light source, and in this case, the light collection position of the light beam from the ellipsoidal mirror is It is preferable that the prism is configured to be positioned in the vicinity of the incident surface of the rod integrator by the light refraction and reflection action of the prism.

  On the other hand, the light source unit may include a parabolic mirror whose focal point is located near the light emission center of the light source, and a condenser lens that collects light from the parabolic mirror. In this case, it is preferable that the condensing position of the light flux from the condenser lens is configured to be located in the vicinity of the incident surface of the rod integrator by the light refraction and reflection action of the prism.

  Further, in the illumination optical system according to the present invention, the light beam traveling on the optical axis of the light source unit is substantially parallel to the optical axis of the rod integrator via the condensing state changing means. It is preferable to be configured to enter the integrator.

  A projection type image display apparatus according to the present invention is modulated by the illumination optical system, a light valve that modulates a light beam from a rod integrator of the illumination optical system according to predetermined video information, and the light valve. And a projection lens that projects an optical image of light on a screen.

  The “light emission center of the light source” means a portion where the light intensity is high in the light emitter constituting the light source, and the “turning” means changing the traveling direction of the light beam.

  According to the illumination optical system and the projection-type image display device according to the present invention, the light incident from each light source unit is directed in a predetermined direction by the condensing state changing unit arranged between the plurality of light source units and the rod integrator. The condensing position of the light beam can be moved a predetermined distance forward in the traveling direction of the light beam. Further, by moving the condensing position of the light beam forward in the traveling direction of the light beam, it is also possible to reduce the light collecting angle of the light beam.

  For this reason, even when a reflecting mirror with a large condensing angle is used in each light source unit, it is possible to appropriately set the incident angle, condensing position, condensing angle, etc. of the light beam incident on the rod integrator from each light source unit. it can. Therefore, it is possible to reduce the light loss in the optical path while increasing the light collection efficiency of the light flux from each light source, so that the illumination illuminance can be increased efficiently and each light source section is configured compactly. Therefore, the overall size can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an illumination optical system according to the first embodiment of the present invention, and FIG. 5 is a schematic configuration of a projection type image display apparatus provided with the illumination optical system according to the first embodiment. FIG.

  The illumination optical system 1A shown in FIG. 1 is arranged between two light source units 2A and 2B, an elongated rectangular parallelepiped rod integrator 4, and two light source units 2A and 2B and the rod integrator 4 arranged on the same plane. And the condensed state changing means 3A.

  Each of the two light source units 2A and 2B includes an ellipsoidal mirror 22 and a light source 21 disposed so that a light emission center is located at one focal position of the ellipsoidal mirror 22, and a light flux from the light source 21 Is output toward the condensing state changing means 3A.

  On the other hand, the condensing state changing means 3A includes two prisms 30A and 30B that transmit light beams from the light source units 2A and 2B, respectively. The two prisms 30A and 30B are respectively the light source units 2A and 2B. The incident surface 31 on which the light beam from the light beam enters, the reflection surface 32 that reflects and changes the incident light beam in the prism, and the output surface 33 that emits the changed light beam. In the present embodiment, the exit surfaces 33 of the two prisms 30A and 30B are arranged so as to be substantially flush with the entrance surface 4a of the rod integrator 4.

  Further, the rod integrator 4 makes the light beam from the light source units 2A and 2B incident through the light collecting state changing means 3A reflected internally a plurality of times, thereby making the light quantity uniform, and then the exit surface. It is comprised so that it may radiate | emit from 4b.

  The ellipsoidal mirrors 22 of the light source units 2A and 2B have a condensing angle set large so that the light flux from the light source 21 can be collected efficiently. On the other hand, the condensing state changing means 3A is provided to appropriately set the incident angle, condensing position, condensing angle, etc. of the light beam emitted from the light source units 2A, 2B and incident on the rod integrator 4. As shown below, the light beam incident from each of the light source units 2A and 2B is redirected, and the light beam condensing angle is moved by moving the light beam condensing position toward the rod integrator 4. Is configured to be small.

  That is, the light beams incident on the prisms 30A and 30B from the light source units 2A and 2B are reflected in the incident surface 31 so that the converging angle is made smaller than that before the incident, in the prisms 30A and 30B. Then, the light is further deflected by the reflecting surface 32, and then enters the incident surface 4a of the rod integrator 4 through the emitting surface 33 while maintaining the state where the condensing angle is small. In addition, the light rays traveling on the optical axes X and Y of the light source units 2A and 2B are substantially parallel to the optical axis Z of the rod integrator 4 (for example, the tilt angle with respect to the optical axis Z is within 10 °). The incident light is incident on the incident surface 4 a of the rod integrator 4, and the condensing position of the light flux from the light source units 2 A and 2 B is positioned in the vicinity of the incident surface 4 a of the rod integrator 4. Yes.

  By such an action of the condensing state changing means 3A, the light flux emitted from the rod integrator 4 is efficiently guided to a light valve or the like disposed in the subsequent stage while suppressing the light amount loss of the light flux incident on the rod integrator 4. It becomes possible. As a glass material used for the prisms 30A and 30B, a general glass material having a refractive index of about 1.5 can be used, but a glass material having a higher refractive index having a refractive index of 1.8 or more is used. It is also possible to use it. The same applies to other prisms in other embodiments.

  Further, the projection type image display apparatus shown in FIG. 5 is a relay composed of the illumination optical system 1A shown in FIG. 1 and a plurality of (in this embodiment, 5) lenses that relay the light flux from the illumination optical system 1A. A lens 5, a light valve 6 (for example, configured by a micromirror device) that carries predetermined image information in the light flux from the relay lens 5, and a projection lens that projects the light flux from the light valve 6 onto a screen 7.

  Next, FIG. 2 is a diagram showing a configuration of an illumination optical system according to the second embodiment of the present invention, and FIG. 6 is a diagram of a projection type image display apparatus provided with the illumination optical system according to the second embodiment. It is a figure which shows schematic structure. In the second embodiment, the same reference numerals and the like are used for the same components as those in the first embodiment, and the detailed description thereof is omitted. The same applies to other embodiments.

  The illumination optical system 1B shown in FIG. 2 is arranged between two light source units 2C and 2D, an elongated rectangular parallelepiped rod integrator 4, and two light source units 2C and 2D and the rod integrator 4 arranged on the same plane. Condensed state changing means 3B.

  The two light source units 2C and 2D each have a parabolic mirror 23, a light source 21 disposed so that a light emission center is located at a focal position of the parabolic mirror 23, and a condenser lens (condenser lens) 24. After the light beam from the light source 21 is converted into a parallel light beam by the parabolic mirror 23, the light beam 21 is condensed by the condenser lens 24 and output toward the condensing state changing means 3B. Yes.

  On the other hand, the condensing state changing unit 3B includes two prisms 30C and 30D that transmit the light beams from the light source units 2C and 2D, respectively. The two prisms 30C and 30D are configured in the same manner as the two prisms 30A and 30B in the first embodiment described above, and their functions are also the same.

  In other words, the light beams incident on the prisms 30C and 30D from the light source units 2C and 2D are reflected in the incident surface 31 so that the converging angle is made smaller than that before the incident due to the refraction action on the incident surface 31. Then, the light is further deflected by the reflecting surface 32, and then enters the incident surface 4a of the rod integrator 4 through the emitting surface 33 while maintaining the state where the condensing angle is small. In addition, the light rays traveling on the optical axes X and Y of the light source units 2C and 2D are substantially parallel to the optical axis Z of the rod integrator 4 (for example, the tilt angle with respect to the optical axis Z is within 10 °). The incident light is incident on the incident surface 4 a of the rod integrator 4, and the condensing position of the light beam from the light source parts 2 C and 2 D is positioned in the vicinity of the incident surface 4 a of the rod integrator 4. Yes.

  Further, the projection type image display apparatus shown in FIG. 6 has a relay composed of the illumination optical system 1B shown in FIG. 2 and a plurality of (in this embodiment, 5) lenses that relay the light flux from the illumination optical system 1B. A lens 5, a light valve 6 (for example, configured by a micromirror device) that carries predetermined image information in the light flux from the relay lens 5, and a projection lens that projects the light flux from the light valve 6 onto a screen 7.

  Next, FIG. 3 is a diagram showing a configuration of an illumination optical system according to the third embodiment of the present invention, and FIG. 4 is a diagram showing a configuration of the illumination optical system according to the fourth embodiment of the present invention. .

  The illumination optical system 1C shown in FIG. 3 is disposed between two light source units 2E and 2F, an elongated rectangular parallelepiped rod integrator 4, and the two light source units 2E and 2F and the rod integrator 4 arranged on the same plane. And the condensed state changing means 3C.

  Each of the two light source units 2E and 2F includes an ellipsoidal mirror 22 and a light source 21 disposed so that a light emission center is located at one focal position of the ellipsoidal mirror 22, and a light flux from the light source 21 The light is condensed and output toward the condensing state changing means 3C, and this point is the same as the two light source units 2A and 2B in the first embodiment. However, the two light source units 2E and 2F in the third embodiment are arranged so that the optical axes X and Y are positioned on the same straight line as shown in FIG.

  Thus, by positioning the optical axes X and Y of the light source units 2E and 2F on the same straight line, there are the following advantages. That is, in some lamps that are generally used as the light source 21, when tilted with respect to the originally set optical axis, output efficiency may be reduced due to heat or the like, and durability may be reduced. On the other hand, since the projection type image display apparatus may be used with the projection direction tilted according to the difference in the height of the screen, the optical axis of the light source lamp does not tilt even when the projection direction is tilted in this way. It is preferable to do so. In the present embodiment, since the optical axes X and Y of the two light source units 2E and 2F are positioned on the same straight line, the optical axes X and Y are perpendicular to the axis of the projection direction. By arranging the light sources 2E and 2F, it is possible to prevent the optical axes X and Y of the respective light sources 21 from being inclined in both the light sources 2E and 2F even when the projection direction is inclined.

  On the other hand, the condensing state changing means 3C includes two prisms 30E and 30F that transmit light beams from the light source units 2E and 2F, respectively. The two prisms 30E and 30F are respectively the light source units 2E and 2F. The incident surface 31 on which the light beam from the light beam enters, the reflection surface 32 that reflects and changes the incident light beam in the prism, and the output surface 33 that emits the changed light beam. In the present embodiment, the exit surfaces 33 of the two prisms 30E and 30F are arranged so as to be inclined with respect to the entrance surface 4a of the rod integrator 4.

  In the present embodiment, the light beams incident on the prisms 30E and 30F from the light source units 2E and 2F are prisms in a state in which the converging angle is made smaller than that before the incidence due to the refracting action on the incident surface 31. The laser beam travels through 30E and 30F, is further deflected by the reflecting surface 32, is then emitted from the exit surface 33, and is incident on the entrance surface 4a of the rod integrator 4. When exiting from the exit surface 33, the light collection angle is slightly increased, but the light beams traveling on the optical axes X and Y of the light source units 2E and 2F are substantially parallel to the optical axis Z of the rod integrator 4. In a state (for example, a state in which the tilt angle with respect to the optical axis Z is within 10 °), the light is incident on the incident surface 4a of the rod integrator 4 and the light collecting positions of the light beams from the light source units 2E and 2F However, it is located in the vicinity of the incident surface 4a of the rod integrator 4 in the same manner as in the second embodiment described above, thereby suppressing the light amount loss of the light beam incident on the rod integrator 4. On the other hand, it is possible to efficiently guide the emitted light beam from the rod integrator 4 to a light valve or the like disposed in the subsequent stage.

  The illumination optical system 1D shown in FIG. 4 includes two light source units 2G and 2H arranged on the same plane, an elongated rectangular parallelepiped rod integrator 4, and between the two light source units 2G and 2H and the rod integrator 4. It has the condensing state change means 3D arranged.

  Each of the two light source units 2G and 2H includes a parabolic mirror 23, a light source 21 disposed so that a light emission center is located at a focal position of the parabolic mirror 23, and a condenser lens 24. After the light beam from the light source 21 is converted into a parallel light beam by the parabolic mirror 23, the light beam 21 is condensed by the condensing lens 24 and is output toward the condensing state changing means 3 </ b> D. Is the same as the two light source units 2C and 2D in the second embodiment described above. However, the two light source sections 2G and 2H in the fourth embodiment are arranged so that the optical axes X and Y are positioned on the same straight line as shown in FIG.

  On the other hand, the condensing state changing means 3D includes two prisms 30G and 30H that transmit the light beams from the light source units 2G and 2H, respectively. The two prisms 30G and 30H are respectively the light source units 2G and 2H. The incident surface 31 on which the light beam from the light beam enters, the reflection surface 32 that reflects and changes the incident light beam in the prism, and the output surface 33 that emits the changed light beam. Further, the exit surfaces 33 of the two prisms 30G and 30H are arranged so as to be inclined with respect to the entrance surface 4a of the rod integrator 4 as in the third embodiment described above.

  In the present embodiment, the light beams incident on the prisms 30G and 30H from the light source units 2G and 2H are prisms in a state in which the condensing angle is made smaller than that before the incidence due to the refracting action on the incident surface 31. The light travels through 30G and 30H and is further redirected by the reflecting surface 32, and then exits from the exit surface 33 and enters the entrance surface 4a of the rod integrator 4. When exiting from the exit surface 33, the light collection angle is slightly increased, but the light rays traveling on the optical axes X and Y of the light source units 2G and 2H are substantially parallel to the optical axis Z of the rod integrator 4. In a state (for example, a state where the tilt angle with respect to the optical axis Z is within 10 °), the light is incident on the incident surface 4a of the rod integrator 4, and the light condensing position of the light beams from the light source units 2G and 2H However, it is located in the vicinity of the incident surface 4a of the rod integrator 4 in the same manner as in the third embodiment described above, thereby suppressing the light amount loss of the light beam incident on the rod integrator 4. On the other hand, it is possible to efficiently guide the emitted light beam from the rod integrator 4 to a light valve or the like disposed in the subsequent stage.

  The illumination optical system according to the present invention and the projection-type image display apparatus including the illumination optical system are not limited to those described above, and various modifications can be made. For example, the configuration and shape of the lens can be changed as appropriate. Is possible.

  Further, the number of light source units of the illumination optical system according to the present invention is not limited to two, and an arbitrary number of 2 or more can be selected, and for example, four light source units can be provided. .

  Further, in the case where a prism is used as the condensing state changing means, the number of reflecting surfaces is not limited to one, and the direction may be changed while being reflected by a plurality of reflecting surfaces in the prism. Furthermore, it is possible to set the incident surface and the output surface to the same surface.

  Further, the condensing state changing means used in the illumination optical system according to the present invention is not limited to the one constituted by the prism described above. For example, the condensing state changing means can be configured by using a condensing lens and a reflecting element that reduce the condensing angle.

Schematic of the illumination optical system according to the first embodiment of the present invention. Schematic of the illumination optical system according to the second embodiment of the present invention Schematic of an illumination optical system according to the third embodiment of the present invention Schematic of the illumination optical system according to the fourth embodiment of the present invention Schematic diagram of a projection-type image display apparatus provided with the illumination optical system shown in FIG. Schematic diagram of a projection type image display apparatus provided with the illumination optical system shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A-1D Illumination optical system 2A-2H Light source part 3A-3D Condensing state change means 4 Rod integrator 4a Incidence surface 4b (Rod integrator) Output surface 5 Relay lens 6 Light valve 7 Projection lens 21 Light source 22 Ellipsoidal mirror 23 Parabolic mirror 24 Condensing lens 30A-30H Prism 31 (Prism) entrance surface 32 (Prism) reflection surface 33 (Prism) exit surface X, Y, Z Optical axis

Claims (9)

An illumination optical system comprising: a plurality of light source units that collect and output a light beam from a light source; and a rod integrator that achieves uniform light quantity of the light beam from the plurality of light source units,
A condensing state in which a light beam incident from each of the plurality of light source units is diverted between the plurality of light source units and the rod integrator, and a condensing position of the light beam is moved forward in a traveling direction of the light beam. An illumination optical system characterized in that a changing means is arranged.   The condensing state changing unit includes a prism that transmits a light beam from the light source unit. The prism reflects an incident surface on which the light beam from the light source unit is incident and reflects the incident light beam in the prism. 2. The illumination optical system according to claim 1, further comprising at least one reflecting surface for redirecting the light beam and an exit surface for emitting the light beam.   The illumination optical system according to claim 1, wherein the light source unit includes an ellipsoidal mirror having one focal point located in the vicinity of the light emission center of the light source.   4. The illumination according to claim 3, wherein a condensing position of a light beam from the ellipsoidal mirror is positioned in the vicinity of an incident surface of the rod integrator by light refraction and reflection action of the prism. Optical system.   2. The light source section includes a parabolic mirror whose focal point is located near the light emission center of the light source, and a condenser lens that collects light from the parabolic mirror. Or the illumination optical system of 2.   6. The illumination optical system according to claim 5, wherein the condensing position of the light beam from the condenser lens is positioned in the vicinity of the incident surface of the rod integrator by light refraction and reflection action of the prism. system.   The light beam traveling on the optical axis of the light source unit is configured to be incident on the rod integrator in a state substantially parallel to the optical axis of the rod integrator via the condensing state changing unit. The illumination optical system according to claim 1, wherein the illumination optical system is any one of claims 1 to 6.   The at least two light source units among the plurality of light source units are configured such that their optical axes are positioned substantially parallel to each other or on the same straight line. 2. An illumination optical system according to item 1. The illumination optical system according to any one of claims 1 to 8, a light valve that modulates a light beam from the rod integrator of the illumination optical system according to predetermined video information, and the light valve modulated by the light valve A projection-type image display device comprising: a projection lens that projects an optical image of light on a screen.

Images