JP2010026260A - Lighting optical device and projection type display device - Google Patents

Abstract

Provided is an illumination optical device capable of reducing light loss generated when combining radiation light from a plurality of light sources, and improving brightness uniformity and combining efficiency.
A plurality of light sources 1a and 1b each having a light emitter 9 and a concave mirror 10 that reflects and collects radiated light from the light emitter, and a plurality of light sources are arranged at a central portion between the light sources. The light synthesis member 2 having the reflection surfaces 2a and 2b for reflecting the radiation light from the light and the rod integrator 3 for collecting the light reflected by the reflection surface of the light synthesis member. The focal points 15a and 15b of the radiated light from the plurality of light sources are respectively between the reflecting surface of the light combining member and the light incident surface of the rod integrator. , Located at a position other than on the reflecting surface and the light incident surface.
[Selection] Figure 1

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 also occurs with respect to 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 at the glass / air interface a plurality of times, 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 plurality of light sources, comprising: a light combining member disposed at a central portion and having a reflecting surface that reflects radiation light from the plurality of light sources; and a rod integrator that collects light reflected by the reflecting surfaces of the light combining members. Each of the focal points of the radiated light from is located between the reflecting surface of the photosynthetic member and the light incident surface of the rod integrator, and is located at a position other than on the reflecting surface and the light incident surface. To do.

  According to the above configuration, compared with the case where the focal position of the radiated light from the plurality of light sources is located on the incident surface of the rod integrator, the range of the light beam condensed at the condensing spot is wide, and the radiation from the light source is The reflection efficiency at the reflection surface of the photosynthetic member for light is increased. As a result, it is possible to reduce the light loss that occurs when the emitted light from the plurality of light sources is combined and to obtain an illumination optical device having a large light output, and a bright projection display device can be realized using this.

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

  That is, in the illumination optical device having the above configuration, when the interval between the reflection surface of the light combining member and the light incident surface of the rod integrator on the optical axis of the emitted light from the light source is L, the optical axis The distance d between the focal position of the radiated light from the light source and the light incident surface of the rod integrator is preferably set in the range of (L / A) ≦ d.

  Further, it is preferable that a distance d between the focal position of the radiated light from the light source on the optical axis and the light incident surface of the rod integrator is set in a range of d ≦ (L / B).

  Moreover, it is preferable that the optical axis of the radiated light from the light source after being reflected by the reflecting surface of the photosynthetic member is parallel to the optical axis of the rod integrator.

  Moreover, it is preferable that an ellipsoidal mirror is used as the concave mirror. The photosynthetic member can be constituted by a prism.

  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 the illumination optical device according to Embodiment 1 of the present invention. The illumination optical device includes two light sources 1 a and 1 b, a combining prism 2, 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 radiated light from the lamps 9 of the light sources 1 a and 1 b is collected by the dielectric multilayer film 12 of the ellipsoidal mirror 10 while being condensed and incident on the combining prism 2. An aluminum film or a dielectric multilayer film is deposited on the reflecting surfaces 2a and 2b of the synthetic prism 2, and reflects visible light efficiently. The reflecting surfaces 2 a and 2 b of the combining prism 2 are adjusted so that the optical axes of the reflected light sources 1 a and 1 b are parallel to the optical axis 14 of the rod integrator 3.

  On the other hand, the second focal points of the ellipsoidal mirrors 10 of the light sources 1 a and 1 b are adjusted so as to be positioned between the reflecting surfaces 2 a and 2 b of the combining prism 2 and the incident surface 3 a of the rod integrator 3. That is, the light collected by the ellipsoidal mirror 10 is reflected by the reflecting surfaces 2a and 2b, and then forms the condensed spots 15a and 15b with the vicinity of the second focal point as the focal point. FIG. 2A shows an enlarged view of the vicinity between the reflecting surfaces 2a and 2b and the entrance surface 3a of the rod integrator 3 in FIG. The condensing spots 15a and 15b are formed at positions spaced apart from the reflecting surfaces 2a and 2b of the combining prism 2 and the incident surface 3a, respectively. The optical axes 16 a and 16 b of the light sources 1 a and 1 b after being reflected by the reflecting surfaces 2 a and 2 b of the combining prism 2 are parallel to the optical axis 14 of the rod integrator 3.

  Light that diverges from the condensed spots 15 a and 15 b is incident on the rod integrator 3. The light incident on the rod integrator 3 propagates through the rod integrator 3 while repeating a total reflection several times at the glass / air interface, and reconstructs a light emitting surface with high uniformity of brightness at the exit end face. The rod integrator 3 is made of, for example, a glass rod.

  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, so that a full color can be obtained using one spatial light modulator (liquid crystal panel 7). 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 condensed spots 15 a and 15 b of the emitted light from the light sources 1 a and 1 b are formed between the reflecting surfaces 2 a and 2 b of the combining prism 2 and the incident surface 3 a of the rod integrator 3. The effect of such a configuration will be described with reference to FIG. 2B. 2B is a cross-sectional view in the same region as FIG. 2A, and shows the configuration of this embodiment and the configuration of the comparative example mixedly. That is, the upper side in FIG. 2B shows the condensing spot 15a in the present embodiment, and the lower side shows the condensing spot 17 in the comparative example.

  On the upper side in FIG. 2B, the condensing spot 15a is formed in front of the incident surface 3a. On the lower side, a condensing spot 17 is formed on the incident surface 3 a of the rod integrator 3. The angle of the range of the reflected light beam from the reflecting surface 2a condensed on the condensing spot 15a is defined as θ1. On the other hand, the angle of the range of the reflected light beam from the reflecting surface 2b condensed on the condensing spot 17 is defined as θ2.

  Since θ1> θ2, the range of the light beam condensed on the condensing spot 15a via the reflection surface 2a is wider than the range of the light beam condensed on the condensing spot 17 via the reflection surface 2b. . Therefore, in the case of the present embodiment, the reflection efficiency at the reflection surface 2a with respect to the radiated light from the light source 1a is higher than in the comparative example. On the other hand, in order to improve the reflection efficiency at the reflection surface 2b involved in the formation of the condensing spot 17, it is necessary to enlarge the reflection surface 2b. In this case, the position of the optical axis 16b of the light source 1b after reflection by the reflecting surface 2b is further away from the optical axis 14, and the cross-sectional dimension of the rod integrator 3 needs to be increased. As a result, the size of the apparatus is unavoidable.

  On the other hand, according to the configuration of the present embodiment, the focal positions of the radiated light from the plurality of light sources 1a and 1b, that is, the condensed spots 15a and 15b are the reflection surfaces 2a and 2b of the combining prism 2 and the rod integrator. 3 is set so as to be located at a position other than on the reflecting surfaces 2a and 2b and the light incident surface 3a. Light efficiency can be obtained.

  In order to obtain the above effects sufficiently practically, the focal positions of the radiated light from the light sources 1a and 1b on the optical axes 16a and 16b, that is, the condensed spots 15a and 15b, and the light incident surface of the rod integrator 3 It is desirable to set the distance between 3a and 3a in an appropriate range in consideration of the area of the light incident surface 3a of the rod integrator 3 and the like. The same applies to the range of distances that separate the positions of the focused spots 15a and 15b from the reflecting surfaces 2a and 2b.

  In the above-described embodiment, an example using two light sources has been described. However, by changing the configuration of the combining prism 2 or the like, the configuration of the present invention is similarly applied to a configuration that combines more light sources. Configuration 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 drawing which shows the effect | action of the illumination optical apparatus and a comparative example 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 2 Synthetic prism 2a, 2b Reflective surface 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 Ellipsoidal mirror 11 Spherical mirror 12 Dielectric multilayer 13 Light emission center 14 Optical axes 15a, 15b, 17 Focusing spots 16a, 16b Optical axes 22a, 22b UV-IR cut filters 23a, 23b Planar mirror 24 Reflecting prisms 24a, 24b Reflecting 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, 44b substantially parallel light beams 45a, 45b azimuth axis 46 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 (5)

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 light combining member disposed in a central portion between the plurality of light sources, and having a reflecting surface that reflects radiation light from the plurality of light sources;
A rod integrator that collects the light reflected by the reflecting surface of the photosynthetic member;
Each focal point of the radiated light from the plurality of light sources is located between the reflecting surface of the light combining member and the light incident surface of the rod integrator, and is located at a position other than the reflecting surface and the light incident surface. An illumination optical device.   The illumination optical apparatus according to claim 1, wherein an optical axis of light emitted from the light source after being reflected by a reflection surface of the light combining member is parallel to an optical axis of the rod integrator.   The illumination optical apparatus according to claim 1, wherein an elliptical mirror is used as the concave mirror.   The illumination optical device according to claim 1, wherein the light combining member is configured by a prism. The illumination optical apparatus according to any one of claims 1 to 4,
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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