JP2010054767A - Projection type image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact, high-efficiency projection type image display device having high color rendering properties, using a second light source, such as a laser, at the same time, in order to display a more bright image with high color reproducibility. <P>SOLUTION: The red laser light is emitted from a red laser light source 10 where a large number of light emitting elements are linearly arrayed, then, the red laser light is one-dimensionally scanned by a polygon mirror 12, and then, transmitted through a field lens 42, thereafter, the red laser light illuminates a spatial optical modulation element 52. On the other hand, light emitted from an ultra-high pressure mercury lamp 20 is transmitted through a different illumination optical system so as to illuminate spacial optical modulation elements 50 and 51. The light beams modulated by the spatial optical modulation elements 50, 51 and 52 are spatially synthesized by a color synthesizing prism 53, thereafter, enlarged and projected onto a screen 55 by a projection optical system 54. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a projection type image display apparatus using light sources having different forms, and can be applied to a projection type image display apparatus such as a projector constituted by an illumination device using both laser light and lamp light.

  Conventionally, as one form for efficiently obtaining a large screen image, a spatial light modulation element such as a small liquid crystal panel that forms an image according to a video signal is illuminated with light from a light source such as a lamp and projected. Projection-type image display devices such as projectors that enlarge and project the optical image onto a screen by a lens are used.

  In such a projection-type image display device such as a projector, it is general to configure the light source with an ultra-high pressure mercury lamp capable of obtaining high luminous efficiency in the visible light wavelength band.

  The ultra-high pressure mercury lamp has the disadvantage that the ratio of the light in the red wavelength region is small relative to the light in the blue and green wavelength regions. A technique for ensuring a balance with the amount of light is used.

  However, it is difficult to achieve high illumination efficiency with such a method that obtains a desired ratio of the emitted light quantity of red by suppressing the emitted light quantity in the blue and green wavelength regions.

  For this reason, as one method for solving the red, green, and blue light intensity problems, it may be possible to construct a light source using a xenon lamp or the like having a balanced emission spectrum as compared with an ultrahigh pressure mercury lamp. There is a disadvantage that the luminous efficiency is inferior.

  In view of this, a method of adding another auxiliary light source has been proposed for a wavelength region in which the light amount is likely to be insufficient in the lamp light that is the main illumination light (see, for example, Patent Documents 1 to 3).

In these methods, laser light is used as the second auxiliary light source in the red wavelength range where the light amount is relatively small in the ultra-high pressure mercury lamp as the first light source. Thereby, the wavelength range of the emission spectrum of the first illumination light can be supplemented by the second illumination light, and a bright image can be displayed with high color reproducibility.
JP 2002-296680 A JP 2003-255465 A JP 2004-29267 A

  However, in Patent Document 1 described above, lamp light and laser light are synthesized by a dichroic mirror. However, since the laser light does not pass through the intensity uniformizing optical system, the spatial light modulation element can be illuminated uniformly. Have difficulty.

  In Patent Document 2 and Patent Document 3, the lamp light and the laser light are combined in the vicinity of the reflector of the lamp light source, but in this configuration, the combined portion of the laser light shields the optical path of the lamp light. It is not suitable for a laser light source using a large output laser light source or a plurality of light emitting elements.

  In order to display a bright image with high color reproducibility while efficiently using illumination light emitted from a first light source such as a lamp, the present invention has been made in view of the above points. An object of the present invention is to provide a projection-type image display device using a small and highly efficient illumination device having a high color rendering property in a projection-type image display device using a second light source such as the above.

  In order to solve the above-described problem, a projection-type image display apparatus according to the present invention includes a first light source in which a plurality of light emitting elements are arranged in a straight line, a second light source having a different form from the first light source, Scanning means for scanning the light emitted from the first light source in a direction orthogonal to the arrangement direction of the plurality of light emitting elements, and modulating the light emitted from the first light source and the second light source according to a video signal And a projection optical system that projects the modulated light emitted from the spatial light modulation element onto a screen.

  Then, by scanning the emitted light in a direction orthogonal to the direction in which the first light sources are arranged, it is possible to obtain illumination light having a uniform luminance distribution with respect to the spatial light modulator.

  In the projection type image display apparatus of the present invention, a semiconductor laser is used as the first light source. In a semiconductor laser, in order to obtain a high output, it is effective to use a configuration in which a plurality of light emitting elements are arranged.

  In the projection type image display device of the present invention, the output light of such a semiconductor laser in which light emitting points having substantially the same output are arranged in a one-dimensional manner is scanned in a one-dimensional manner in a direction orthogonal to the arrangement direction. Thereby, it is possible to obtain uniform illumination light using laser light with a simple configuration.

  In the projection type image display apparatus of the present invention, when using a semiconductor laser, the center wavelength is a red color gamut of 600 nm to 700 nm, and a discharge lamp is used as the second light source. It is characterized by. The ultra-high pressure mercury lamp that is most commonly used in a projection-type image display apparatus has a feature that the intensity of the red color gamut is relatively lower than that of blue and green. Therefore, it is useful to supplement the light of this color gamut with the first light source.

  In the projection type image display apparatus of the present invention, a galvanometer mirror or a polygon mirror is used as a scanning means for the emitted light from the first light source. The galvanometer mirror and the polygon mirror are suitable as means for obtaining a one-dimensional scan with small size and high accuracy.

  Furthermore, the projection type image display device of the present invention is characterized by comprising illumination light combining means for spatially combining the emitted light from the first light source and a part of the emitted light from the second light source. .

  Among the second light sources, the light of the wavelength band near the first light source is spatially synthesized to illuminate the spatial light modulation element as the same optical path, thereby further increasing the brightness of the projection type image display device. Obtainable.

  According to the present invention, an image formed by a spatial light modulator is illuminated using a white light source such as a lamp and a light source having excellent monochromaticity such as a laser, and projected onto a screen using a projection lens. In a projection-type image display device, a small-sized and highly efficient illumination device can be provided by scanning a laser beam emitted from a laser light source in which a plurality of light emitting elements are linearly arranged in one dimension, and a spatial light modulation element By providing the projection optical system, it is possible to realize a projection type image display device with high color rendering properties.

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

(Embodiment 1)
FIG. 1 is a schematic configuration diagram illustrating a projection type image display apparatus according to Embodiment 1 of the present invention, and FIG. 2 is a perspective view of a red laser light source and a collimating lens.

  In the present embodiment, an ultrahigh pressure mercury lamp and a red laser light source are used as the light source, the first light source is the red laser light source 10, and the second light source is the ultrahigh pressure mercury lamp 20. Further, as the spatial light modulator, three transmissive liquid crystal modulators 50, 51, and 52 for red, green, and blue color gamuts are used.

  As shown in FIG. 2, the red laser light source 10 is a semiconductor laser that directly oscillates at a wavelength of 640 nm, and a large number of light emitting elements are arranged in a straight line. In the present embodiment, the light emitting elements 101 constituting the red laser light source 10 are arranged with 26 light emitting elements at a pitch of 0.4 mm.

  A coordinate system is used in which the arrangement direction of the light emitting elements 101 is the X axis, the emission direction of the laser light is the Z axis, and the remaining axes are the Y axis. The emitted light from the light emitting element 101 generally has different divergence angles in the X-axis direction and the Y-axis direction.

  In the light-emitting element 101 used in this embodiment, the X-axis direction is a SLOW axis (a direction in which the divergence angle is small), and the Y-axis direction is a FAST axis (a direction in which the divergence angle is large). A collimating lens 11 that is a cylindrical lens is arranged for collimation (parallelization) in the FAST axis direction.

  The red laser light whose FAST axis direction is substantially parallel light is incident on the polygon mirror 12 which is a one-dimensional scanning means. The polygon mirror 12 is a total reflection mirror whose cross section perpendicular to the rotation axis has a regular decagonal shape.

  The red laser light scanned one-dimensionally by the polygon mirror 12 illuminates the spatial light modulation element 52 after passing through the field lens 42. The scanning frequency of the polygon mirror 12 is set to be sufficiently higher than the modulation frequency of the spatial light modulation element 52.

  Uniform illumination of the red semiconductor laser light is achieved by scanning the polygon mirror 12 in the Y-axis direction. About the X-axis direction, it utilizes that the substantially uniform light emitting element 101 is located in a line.

  By making the spatial light modulation element 52 shifted from a position conjugate with the emission end face of the red laser light source 10, uniform illumination without unevenness can be obtained.

  On the other hand, the light emitted from the extra-high pressure mercury lamp 20 illuminates the spatial light modulation elements 50 and 51 through different illumination optical systems. First, the light emitted from the ultra-high pressure mercury lamp 20 passes through the reflector 21 and the collimating lens 22 to become substantially collimated light, and then passes through the lens array 23 and the lens array 24, thereby achieving uniform brightness. The Then, after being aligned with linearly polarized light by the polarization beam splitter 25, it passes through the condenser lens 26.

  Further, the dichroic mirror 30 reflects only light in the blue color gamut out of the white light components. The reflected blue light is bent by the total reflection mirror 31 and then passes through the field lens 40 to illuminate the spatial light modulator 50.

  Of the red and green color gamut components that have passed through the dichroic mirror 30, light in the green color gamut is reflected by the dichroic mirror 32, passes through the field lens 41, and illuminates the spatial light modulator 51.

  The light modulated by the spatial light modulation elements 50, 51, 52 is spatially synthesized by the color synthesis prism 53 and then enlarged and projected onto the screen 55 by the projection optical system 54.

  In the present embodiment, the dichroic mirror 30 transmits green light and reflects blue light. However, it may be configured to reflect green light and transmit blue light.

  Further, although the transmission type liquid crystal modulation element is used as the spatial light modulation element, a reflection type liquid crystal modulation element or a digital micromirror device may be used.

  In this apparatus, the configuration from the light source to the field lenses 40, 41, and 42, which are relay optical systems, is an illuminating device, and this illuminating device can also be used independently. The same applies to the second embodiment described below.

  As in this embodiment, by using semiconductor laser light for the red color gamut, an image display device with high color rendering can be obtained. At that time, by using a polygon mirror in the red illumination optical system, It is possible to configure a small and highly efficient lighting device.

(Embodiment 2)
FIG. 3 is a schematic configuration diagram for explaining a projection-type image display apparatus according to Embodiment 2 of the present invention, and FIGS. 4 and 5 are spectrum characteristic diagrams.

  In the present embodiment, the first light source and the second light source use the same light source as in the first embodiment, but the red light that has passed through the dichroic mirror 32 in the illumination optical system of the second light source. Is configured to use. Other configurations are the same as those of the first embodiment.

  That is, the red light from the ultra-high pressure mercury lamp 20 that is transmitted through the dichroic mirror 32 passes through the relay lenses 60 and 61 and the total reflection mirror 62 and is then used by the dichroic mirror 63 to obtain the red laser light source 10. Is spatially combined with the red light emitted from the polygon mirror 12 and scanned one-dimensionally by the polygon mirror 12.

  In this configuration, the same red light is multiplexed by utilizing the difference between the spectrum of the semiconductor laser and the spectrum shape of the lamp light.

  FIG. 4 shows a transmission spectrum of the dichroic mirror 63. As can be seen from the figure, it has a characteristic of transmitting only a narrow band around 640 nm, and the other wavelength regions have high reflectivity.

  The red laser light source 10 has a narrow-band spectrum with a center wavelength of 640 nm, whereas the red light from the ultra-high pressure mercury lamp 20 has a broadband spectrum.

  Therefore, by inserting the dichroic mirror 63 having the characteristic of transmitting only the wavelength band of the laser light, it is possible to combine the two red lights with a small loss.

  FIG. 5 shows a spectrum when white is output on the screen 55 in the present embodiment.

  In the present embodiment, since red light in the light emitted from the extra-high pressure mercury lamp 20 is also used, it is possible to provide a projection type image display apparatus using a brighter illumination device as compared with the first embodiment. it can.

  In these embodiments, a polygon mirror is used, but a galvanometer mirror may be used.

  The projection-type image display device of the present invention can provide illumination light having high brightness and smoothed brightness in the illumination area by a simple method, and a projector using a laser light source as the illumination device It is useful for projection type image display devices such as.

1 is a schematic configuration diagram of a projection type image display apparatus according to Embodiment 1 of the present invention. 1 is a perspective view of a red laser light source and a collimating lens according to Embodiment 1 of the present invention. Schematic configuration diagram of a projection type image display apparatus according to Embodiment 2 of the present invention Spectrum characteristic diagram of dichroic filter according to Embodiment 2 of the present invention Spectral characteristic diagram of projected light at the time of white output according to Embodiment 2 of the present invention

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Red laser light source 11 Collimating lens 12 Polygon mirror 20 Super high pressure mercury lamp 21 Reflector 22 Collimating lens 23, 24 Lens array 25 Polarizing beam splitter 26 Condensing lens 30, 32, 63 Dichroic mirror 31, 62 Total reflection mirror 40-42 field Lens 50 to 52 Spatial light modulation element 53 Color synthesis prism 54 Projection optical system 55 Screen 60, 61 Relay lens 101 Light emitting element

Claims (9)

A first light source in which a plurality of light emitting elements are arranged in a straight line, a second light source having a different form from the first light source, and an array of the plurality of light emitting elements that emit light from the first light source Scanning means for scanning in a direction orthogonal to the direction, a spatial light modulation element for modulating light emitted from the first light source and the second light source in accordance with a video signal, and a modulation emitted from the spatial light modulation element A projection type image display device comprising: a projection optical system that projects light onto a screen. The projection type image display apparatus according to claim 1, wherein the first light source is a semiconductor laser. The projection type image display device according to claim 2, wherein a center wavelength of the first light source is a red color gamut of 600 nm to 700 nm. The projection type image display apparatus according to claim 2, wherein a collimating lens is disposed between the first light source and the scanning unit. The projection type image display device according to claim 1, wherein the second light source is a discharge lamp. The projection type image display device according to claim 1, wherein the scanning unit is a galvanometer mirror or a polygon mirror. The projection type image display device according to claim 1, wherein the spatial light modulator is configured to be shifted from a position conjugate with an emission end face of the first light source. The projection-type image display according to claim 1, further comprising illumination light combining means for spatially combining a part of the light emitted from the first light source and a part of the light emitted from the second light source. apparatus. 9. The projection type image display apparatus according to claim 1, wherein a transmissive liquid crystal modulation element is used as the spatial light modulation element.

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