JP5097042B2 - Illumination optical device and projection display device using the same - Google Patents

Description

  The present invention provides, for example, an illumination optical device used for illuminating a spatial light modulator, and illuminates the spatial light modulator using the illumination optical device, and projects the obtained optical image on a screen by a projection lens. The present invention relates to a projection display device for performing the above.

  As one of the methods for displaying a large screen image, there is known a projection display device that illuminates a spatial light modulation element that forms an optical image corresponding to a video signal with light, and enlarges and projects the optical image by a projection lens. Yes. As the spatial light modulation element, for example, a liquid crystal panel or DMD (digital micromirror device) is used. In such a projection display device, there is a strong demand for higher brightness of a projected image.

  In order to improve the brightness of the projected image in the projection display device, the power consumption of the lamp may be increased. However, if the power consumption is increased while ensuring a sufficient lamp life, there is a problem that the shape of the light emitter becomes longer and thicker, and the light utilization efficiency of the optical system decreases. Thus, it is known to improve the above-described problem by using a plurality of lamps with relatively low power consumption, and to efficiently improve the brightness of the projection display device.

  For example, Patent Document 1 discloses a projection display device as shown in FIG. In this apparatus, when a plurality of lamps are used, the illumination optical apparatus is configured to efficiently collect the radiated light of each lamp and form highly uniform illumination light. FIG. 3 is a front view showing the overall configuration of the projection display apparatus.

  The projection display device includes lamps 20a and 20b, ellipsoidal mirrors 21a and 21b, UV-IR cut filters 22a and 22b, plane mirrors 23a and 23b, a reflecting prism 24, a condensing lens 25, a first lens array 26, a first A two-lens array 27, a beam combining lens 28, a field lens 29, a liquid crystal panel 30, and a projection lens 31 are included.

  As the lamps 20a and 20b, metal halide lamps, ultra-high pressure mercury lamps, xenon lamps or the like are used, and the emission centers are arranged in the vicinity of the first focal points of the ellipsoidal mirrors 21a and 21b. The light emitted from the lamps 20a and 20b is collected by the corresponding ellipsoidal mirrors 21a and 21b, respectively, and after the ultraviolet and infrared light components are removed by the UV-IR cut filters 22a and 22b, By 23b, the optical path is bent so as to go to the reflecting surfaces 24a and 24b of the reflecting prism 24. The reflecting prism 24 is disposed in the vicinity of the second focal point of the ellipsoidal mirrors 21a and 21b. Thereby, the condensing spots of the lamps 20a and 20b are formed in the vicinity of the reflecting surfaces 24a and 24b of the reflecting prism 24.

  An aluminum film or a dielectric multilayer film is deposited on the reflecting surfaces 24a and 24b of the reflecting prism 24, and reflects visible light efficiently. The light reflected by the reflecting prism 24 is divergent light and enters the condenser lens 25. As the condenser lens 25, for example, an aspherical biconvex lens is used, and the incident light is converted into substantially parallel light.

  The parallel light flux from the condenser lens 25 is incident on the first lens array 26 composed of a plurality of lenses and is divided into a large number of minute light fluxes. A large number of minute light beams converge on the corresponding lenses of the second lens array 27 each composed of a plurality of lenses, and a large number of images of the lamps 20a and 20b are formed. The second lens array 27 has the same shape as the first lens array 26.

  Each rectangular lens of the second lens array 27 expands a minute light beam from the corresponding first lens array 26 and illuminates the liquid crystal panel surface 30 via the beam combining lens 28 and the field lens 29. The beam combining lens 28 is used to superimpose the light emitted from each rectangular lens of the second lens array 27 on the liquid crystal panel 30. In this way, the incident light flux of the first lens array 26 is divided into a large number of minute light fluxes, which are enlarged and superimposed on the liquid crystal panel 30, so that the liquid crystal panel 30 can be illuminated with good uniformity. .

  The field lens 29 condenses the light that illuminates the liquid crystal panel 30 on the pupil plane of the projection lens 31. The projection lens 31 projects an optical image formed on the liquid crystal panel 30 onto a screen (not shown).

  According to the said structure, in the structure which illuminates a liquid crystal panel with a some lamp | ramp, the emitted light of each lamp | ramp can be efficiently condensed and illumination light with high uniformity can be formed.

  On the other hand, when using a plurality of lamps as described above, after combining the emitted light from each lamp, the illuminance uniformity and color uniformity of the illumination light were improved by using a rod integrator instead of the lens array The configuration is disclosed in Patent Document 2. This will be described with reference to FIG.

  In FIG. 4, the light source means 40 includes a first light source 41a and a second light source 41b. The first light source 41a emits a substantially parallel light beam 44a by the first light emitter 42a and the first parabolic mirror 43a. Similar to the first light source 41a, the second light source 41b includes a second light emitter 42b and a second parabolic mirror 43b, and emits a substantially parallel light beam 44b. The directions in which the substantially parallel light beams 44a and 44b are emitted are shown as azimuth axes 45a and 45b.

  The light beam combining means 46 includes a first optical element 47 having two light incident surfaces each having a gently curved surface, and two second optical elements 48a and 48b disposed in close contact with the light incident surfaces. Has been. The light incident surfaces of the second optical elements 48a and 48b are configured as a plane on which incident light from the corresponding light source enters substantially perpendicularly. Further, the light exit surface 49 of the first optical element 47 is a plane perpendicular to the optical axis 50.

  The outgoing light from the first optical element 47 enters a rod integrator 51 having a light incident end face and an outgoing end face. Light emitted from the rod integrator 51 is incident on a light transmission means 52 composed of a plurality of types of lens means. The light transmission means 52 includes a first lens system 53 that substantially collimates the divergent light beam from the rod integrator 51. Note that illustration of other elements included in the light transmission means 52 is omitted.

  The substantially parallel light beam from the first light source 41 a is deflected and condensed by the second optical element 48 a and the first optical element 47 so as to go to the incident point P of the rod integrator 51. This light condensing action is similarly generated for a substantially parallel light beam from the second light source 41b. The light beams from the two light sources thus condensed are combined toward the incident point P at a predetermined angle.

The light collected at the incident point P of the rod integrator 51 propagates through the rod integrator 51 while repeating the total reflection several times at the glass / air interface, and forms a light emitting surface with high brightness uniformity at the exit end face. Reconfigure.
JP 2000-3612 A JP 2000-250136 A

  By using a rod integrator as in the above-mentioned example of Patent Document 2, a light emitting surface with high uniformity can be reconfigured with a simple configuration, so that the brightness of a projection screen with a plurality of light sources can be increased. Useful for configuration.

  On the other hand, since the opening at the entrance end of the rod integrator is too small to arrange a plurality of light sources in parallel, it is difficult to make the condensing points of the light sources coincide on the entrance end surface. In order to solve this problem, the light beam synthesizing means 46 is used in Patent Document 2. However, the configuration of the light beam synthesizing means 46 is complicated and difficult to manufacture with high accuracy.

  On the other hand, the present inventors examined the structure which synthesize | combines the emitted light of several lamp 20a, 20b by the reflecting prism 24 and a rod integrator like patent document 1 shown in FIG. That is, the radiated light of a plurality of lamps is reflected by the reflecting prism 24 as shown in FIG. 3 and then incident from the incident surface of the rod integrator. In that case, as in Patent Document 2, it was found that when the focal position of the radiated light was matched with the incident surface of the rod integrator, the reflection efficiency on the reflecting surface of the prism was not optimal.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an illumination optical device that can reduce light loss that occurs during the synthesis of radiated light from a plurality of light sources, and can improve brightness uniformity and synthesis efficiency.

  It is another object of the present invention to provide a projection display device using a plurality of light sources that can achieve both high brightness and improved brightness uniformity of a projected image using the illumination optical device.

In order to solve the above problems, an illumination optical device according to the present invention includes a light source and a plurality of light sources each having a concave mirror that reflects and collects radiated light from the light emitter, and the plurality of light sources. A rod integrator that collects light from the plurality of light sources, and a light incident surface that is arranged for each of the plurality of light sources and that faces the light incident surface of the rod integrator. , and a plurality of triangular prism having a reflecting surface inclined with respect to the incident surface and exit surface, wherein the plurality of triangular prisms, and guides the light from the plurality of light sources to the incident surface of each of the rod integrator The focal points of the light from the plurality of light sources respectively collected by the concave mirror are located between the incident surface and the reflecting surface of the triangular prism .

  According to the above configuration, the radiated light from the light source can be efficiently propagated to the incident surface of the rod integrator by the triangular prism having a simple configuration. Therefore, it is possible to obtain an illumination optical device having a high light output by reducing the light loss generated when synthesizing the radiated light from several light sources with high efficiency when guiding the radiated light from the light source to the rod integrator. By using this, a bright projection display device can be realized.

  The present invention can take the following aspects based on the above configuration.

  That is, it is preferable that the focal points of the light from the plurality of light sources collected by the concave mirror are located on the reflection surface of the triangular prism.

  Moreover, it is preferable that the optical axis of the emitted light from the triangular prism is parallel to the optical axis of the rod integrator.

  The incident surface of the triangular prism is preferably located on the same plane as the side surface of the rod integrator.

  Moreover, it is preferable that an ellipsoidal mirror is used as the concave mirror.

  A projection display device according to the present invention includes an illumination optical device having any one of the above configurations, an optical system that condenses light emitted from the rod integrator to form illumination light, and the illumination light is incident on an image signal. A spatial light modulation element that modulates the corresponding incident light and a projection lens that projects the light modulated by the spatial light modulation element onto the screen can be used.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment)
FIG. 1 is a cross-sectional view showing a projection display device including an illumination optical device according to Embodiment 1 of the present invention. The illumination optical device includes two light sources 1a and 1b, triangular prisms 2a and 2b, and a rod integrator 3. A projection display device is configured by adding a color wheel 4, a relay lens 5, a field lens 6, a liquid crystal panel 7 as an example of a spatial light modulation element, and a projection lens 8 to the illumination optical device.

  Each of the two light sources 1a and 1b includes a lamp 9, an ellipsoidal mirror 10, and a spherical mirror 11. As the lamp 9, a metal halide lamp, an ultra high pressure mercury lamp, a xenon lamp, or the like can be used. The combination of the ellipsoidal mirror 10 and the spherical mirror 11 efficiently collects the emitted light from the lamp 9.

  On the reflecting surface of the ellipsoidal mirror 10, for example, a dielectric multilayer film 12 that efficiently reflects visible light and transmits infrared light is formed. Of the light emitted from the lamp 9, the visible light component Is efficiently reflected in a desired direction. The lamp 9 is arranged such that the emission center 13 substantially coincides with the first focal point of the ellipsoidal mirror 10. Thereby, a condensing spot proportional to the size of the light source is formed in the vicinity of the second focal point of the ellipsoidal mirror 10, and the emitted light of the lamp 9 can be efficiently condensed.

  The spherical mirror 11 is provided on the same side as the ellipsoidal mirror 10 with respect to the light emission center 13 of the lamp 9. The center of the spherical mirror 11 is arranged so as to be substantially coincident with the light emission center 13 and reflects light in the range of 90 degrees out of the emitted light of the lamp 9. Thereby, the light incident on the spherical mirror 11 out of the radiated light of the lamp 9 is reflected and enters the ellipsoidal mirror 10.

  The ellipsoidal mirror 10 removes ultraviolet light and infrared light components from the radiated light of the lamp 9 by the dielectric multilayer film 12, collects the light, and makes it incident on the triangular prisms 2a and 2b. The triangular prisms 2 a and 2 b reflect incident light by the reflecting surfaces 14 a and 14 b and make the incident light enter the rod integrator 3. The rod integrator 3 is made of, for example, a glass rod. FIG. 2 is an enlarged view of the vicinity of the incident surfaces of the triangular prisms 2a and 2b and the rod integrator 3 in FIG. The triangular prisms 2a and 2b include light incident surfaces 15a and 15b from the light sources 1a and 1b, exit surfaces 16a and 16b facing the incident surface 3a of the rod integrator 3, and reflecting surfaces 14a and 14b inclined with respect to them. Have.

  The incident surfaces 15 a and 15 b of the triangular prisms 2 a and 2 b are preferably configured to be located on the same plane as the side surface of the rod integrator 3. Thereby, the incident surfaces 15a and 15b function as an efficient reflecting surface that guides the incident light to the incident surface 3a of the rod integrator 3 with respect to the light flux such that the reflected light from the reflecting surfaces 14a and 14b returns to the incident surfaces 15a and 15b. can do.

  The exit surfaces 16 a and 16 b of the triangular prisms 2 a and 2 b are arranged in close contact with the entrance surface 3 a of the rod integrator 3. It is desirable that the optical axis of the light emitted from the triangular prism is adjusted so as to be substantially parallel to the optical axis of the rod integrator. Therefore, in the present embodiment, the angle θ formed between the reflecting surfaces 14 a and 14 b with respect to the optical axis 17 of the rod integrator 3 is adjusted to 45 degrees. The focal points of light from the light sources 1a and 1b collected by the ellipsoidal mirror 10 are adjusted so as to be positioned on the reflecting surfaces 14a and 14b of the triangular prisms 2a and 2b.

  With the above configuration, the light emitted from the light sources 1a and 1b is guided to the rod integrator 3 and synthesized. That is, the light emitted from the lamps 9 of the light sources 1a and 1b is collected by the ellipsoidal mirror 10 to form a condensed spot on the reflecting surfaces 14a and 14b of the triangular prisms 2a and 2b. The condensed spot is reflected by the reflecting surfaces 14 a and 14 b and enters the rod integrator 3 through the emitting surfaces 16 a and 16 b. The light incident on the rod integrator 3 propagates through the rod integrator 3 while repeating total reflection at the glass / air interface a plurality of times, and reconstructs a light emitting surface with high uniformity of brightness at the exit end face.

  The light emitted from the rod integrator 3 is color-divided by passing through the color wheel 4. The color wheel 4 is configured by combining three types of color filters that transmit only one of each of the three primary colors. By the color wheel 4, the white light output from the light sources 1a and 1b is time-divided into three primary colors of red, green and blue. The light that has passed through the color wheel 4 is applied to the liquid crystal panel 7 via the relay lens 5 and the field lens 6. By rotating the color wheel 4, light of the three primary colors of red, green, and blue is sequentially irradiated onto the liquid crystal panel 7 in a time-sharing manner. Therefore, using one spatial light modulator (liquid crystal panel 7), Full-color projected images can be displayed.

  The field lens 6 condenses the light irradiated on the liquid crystal panel 7 on the pupil plane of the projection lens 8. The projection lens 8 projects an optical image formed on the liquid crystal panel 7 on a screen (not shown).

  As described above, the focal points of the radiated light from the light sources 1a and 1b are located on the reflecting surfaces 14a and 14b of the triangular prisms 2a and 2b, and the divergent light from the condensed spots formed in the vicinity of the focal points is efficiently converted into a rod integrator. 3 is reflected toward the incident surface 3a. Therefore, it is possible to avoid the light loss that occurs when combining the radiated light from the plurality of light sources due to insufficient reflection efficiency on the reflecting surface of the reflecting prism as in Patent Document 1. It is possible to improve uniformity and synthesis efficiency.

  In the figure, the focus of the radiated light from the light sources 1a and 1b is shown on the reflecting surfaces 14a and 14b of the triangular prisms 2a and 2b, but there is no particular limitation. However, it is more effective if it is between the incident surface and the reflecting surface of the triangular prisms 2a and 2b.

  In the above embodiment, an example in which two light sources are used has been described. However, the configuration of the present invention is similarly applied to a configuration in which more light sources are combined by changing the arrangement of triangular prisms or the like. Can be applied.

  The illumination optical device of the present invention can reduce light loss that occurs when combining light emitted from a plurality of light sources, improve brightness uniformity and combining efficiency, and can be used in a projection display device or the like. Useful.

Sectional drawing which shows the projection type display apparatus provided with the illumination optical apparatus in one embodiment of this invention Sectional drawing which shows the principal part of the illumination optical apparatus Sectional view showing a conventional projection display device Sectional drawing which shows the projection type display apparatus of another prior art example

Explanation of symbols

1a, 1b Light source 2a, 2b Triangular prism 3 Rod integrator 3a Incident surface 4 Color wheel 5 Relay lens 6, 29 Field lens 7, 30 Liquid crystal panel 8, 31 Projection lens 9, 20a, 20b Lamp 10, 21a, 21b Elliptical mirror DESCRIPTION OF SYMBOLS 11 Spherical mirror 12 Dielectric multilayer film 13 Light emission center 14a, 14b Reflection surface 15a, 15b Incidence surface 16a, 16b Output surface 17 Optical axis 22a, 22b UV-IR cut filter 23a, 23b Planar mirror 24 Reflection prism 24a, 24b Reflection surface 25 Condensing lenses 26 and 27 First and second lens arrays 28 Beam combining lens 40 Light source means 41a and 41b First and second light sources 42a and 42b First and second light emitters 43a and 43b First and second Parabolic mirrors 44a and 44b Nearly parallel light beams 45a and 45b Azimuth axis 46 Stage 47 first optical element 48a, 48b second optical element 49 light emitting surface 50 the optical axis 51 the rod integrator 52 the light transmitting means 53 first lens system

Claims (2)

A plurality of light sources each having a light emitter and a concave mirror that reflects and collects radiation emitted from the light emitter;
A rod integrator that is arranged in a central portion between the plurality of light sources and collects light from the plurality of light sources;
A plurality of triangular prisms arranged for each of the plurality of light sources, each having a light incident surface from the light source, an exit surface facing the entrance surface of the rod integrator, and a reflective surface inclined with respect to the entrance surface and the exit surface And
The plurality of triangular prisms guide light from the plurality of light sources to the incident surface of the rod integrator, respectively .
The illumination optical device, wherein the focal points of the light from the plurality of light sources respectively collected by the concave mirror are located between the incident surface and the reflection surface of the triangular prism. An illumination optical system according to claim 1 Symbol placement,
An optical system for collecting illumination light from the rod integrator to form illumination light;
A spatial light modulator that modulates incident light according to a video signal when the illumination light is incident;
A projection display device, comprising: a projection lens that projects light modulated by the spatial light modulator on a screen.

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