JP2008176083A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image display device capable of reproducing colors in a wider color range, suppressing the output load of a laser and reducing power consumption. <P>SOLUTION: The image display device 1 includes: a main light source 6 emitting white light; color separation optics 16, 17, 23 separating the white light into three wavelength bands of a red band, a green band and a blue band; spatial modulators 3R, 3G, 3B modulating light in the three wavelength bands to form an image; a red auxiliary light source 8 emitting a red laser beam; and a synthesizing dichroic mirror 17 for a red color synthesizing the light in the red band separated by the color separation optics with the red laser beam. The synthesizing dichroic mirror 17 for a red color transmits the wavelength band in the emission spectral linewidth of the red laser beam and reflects light in a longer wavelength band to direct it to the spatial modulator 3R. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an image display device suitable for application to a projector using, for example, an ultra-high pressure mercury lamp as a white light source. More specifically, the light from an auxiliary light source is combined with the light from a white light source to emit light in a specific wavelength band. The present invention relates to an image display device having a configuration for increasing the number of images.

  Conventionally, a projector as an image display device separates illumination light emitted from a predetermined light source into red, blue, and green wavelength bands and modulates each of them with a spatial modulation element such as a liquid crystal display panel. A color display image is formed by projecting and superimposing the light emitted from the element on a screen. In such a projector, it is possible to efficiently emit illumination light by configuring the light source with an ultra-high pressure mercury lamp (hereinafter also referred to as “UHP lamp”) having high luminous efficiency in the visible light wavelength band. Has been made.

  FIG. 13 shows the emission spectrum of the UHP lamp. The vertical axis is intensity, [a. u. ] Means “arbitrary unit”. The UHP lamp can secure a sufficient amount of light in the wavelength band near 550 nm, which is the green wavelength band, and has a large spectrum in the wavelength band near 440 nm for blue. On the other hand, in the wavelength band of 600 nm or more, which is the red wavelength band, a sufficient amount of light cannot be secured as compared with the blue and green wavelength bands.

  For this reason, in a conventional projector, by suppressing the amount of emitted light in the blue and green wavelength bands, a balance with the amount of emitted light in the red wavelength band is achieved, and sufficient color reproducibility is ensured. In particular, the green color is largely suppressed to achieve white balance, and the light quantity emitted from the red and blue wavelength bands is balanced at a considerable cost.

  As described above, when the amount of emitted light in the blue and green wavelength bands is suppressed to balance the amount of emitted light in the red wavelength band, in the end, part of the illumination light emitted from the light source is wasted. It is inevitable that the display screen will darken accordingly. In particular, since the brightness greatly depends on the amount of emitted light in the green wavelength band, suppressing this particularly reduces the lumen.

  As one method for solving this problem, it is conceivable to configure a light source using a xenon lamp or the like having a balanced emission spectrum as compared with a UHP lamp. However, a xenon lamp or the like has a disadvantage that its luminous efficiency is inferior to that of a UHP lamp. For this reason, there is a problem that the power consumption is remarkably increased if an attempt is made to secure the same level of brightness as when the light source is configured by a xenon lamp or the like and the light source is configured by a UHP lamp.

  On the other hand, for example, as disclosed in Patent Document 1 below, a method of generating illumination light using a light source that individually emits light in the red, blue, and green wavelength bands is also conceivable. However, at present, such individual monochromatic light sources include solid-state lasers, gas lasers, semiconductor lasers, light-emitting diodes, etc. Among these, elements that emit light in the green wavelength band have high output. In addition, there is a drawback that it is difficult to obtain a highly versatile one.

  Incidentally, a method of obtaining a high output by using a plurality of low output elements is also conceivable, but in this case, the etendue of the light source (the product of the area of the light source and the radiation solid angle) becomes large and the size is about 1 inch diagonal. Even if the spatial modulation element is illuminated from such a light source, the illumination efficiency is saturated, and eventually it is difficult to display a bright image above the saturation level.

  On the other hand, in addition to a white light source such as a lamp, an auxiliary light source that generates light in a specific wavelength band is added to efficiently use illumination light to obtain a high color reproducibility and a brighter image. Various configurations have been proposed.

  For example, in the following Patent Documents 2 to 6, by synthesizing main illumination light and sub-illumination light from a substantially white lamp or the like, and enhancing the emission spectrum of the sub-illumination light to generate illumination light By using illumination light emitted from a light source such as a lamp efficiently, a bright image can be displayed with high color reproducibility. Here, the secondary illumination light includes a red laser or a red light emitting diode, and is used by being combined with main illumination light from a lamp or the like that is substantially white. All of the combining methods are performed using main illumination light such as a lamp and the first-stage optical system, and perform color separation to irradiate the spatial modulation elements of each color after combining.

  Various methods are used to combine the main illumination light and the sub-illumination light by a lamp that is almost white, etc., but the wavelength band of the sub-illumination light is reflected and other main illuminations are used. A dichroic mirror (or vice versa) that transmits the light wavelength band is often used. In this case, for the color of the secondary illumination light, only that much color reproduction can be expressed, and only the output of the secondary illumination light can be used for that color. Therefore, when trying to obtain a bright image, the output of the secondary illumination light is subjected to a considerable load.

  Patent Document 7 below describes an image display device that uses a reflection type hologram element to synthesize main illumination light and sub-illumination light from a substantially white lamp or the like. This image display apparatus is configured to reflect the vicinity of the spectrum of the secondary illumination light, transmit the other wavelength bands, maintain a wide color reproduction, and reduce the output load of the secondary illumination light. .

  Furthermore, in Patent Document 8 below, the main illumination light from a lamp or the like that is substantially white is separated into blue, green, and red, and then combined with the secondary illumination light of red, and irradiated to the spatial modulation element, A configuration of an image display device that increases the amount of red light is disclosed. FIG. 14 is a schematic configuration diagram of the image display apparatus. In the figure, 101 is a main light source that generates white light, and 102 is a color separation including dichroic mirrors 102G and 102B for separating the white light generated by the main light source 101 into light in the red band, green band, and blue band. An optical system, 103R, 103G, and 103B are transmissive liquid crystal display panels as spatial modulation elements for red, green, and blue, respectively, and 104 synthesizes light emitted from the spatial modulation elements 103R, 103G, and 103B for each color. The combining prism 105 is a projection lens that enlarges and projects the light emitted from the combining prism 104 onto a screen (not shown).

  The image display apparatus 100 shown in FIG. 14 includes a light emitting diode (semiconductor light emitting element) 106 having a light emission intensity distribution as shown in FIG. 15 and emits red light and light emitted by the color separation optical system 102. The red monochromatic light generated by the diode 106 is combined and incident on the spatial modulation element 103R. For the synthesis of the red light color-separated by the color separation optical system 102 and the red monochromatic light generated by the light emitting diode 106, the separated red light is reflected and the red monochromatic light generated by the light emitting diode 106 is transmitted. 107 is used. As shown in FIG. 15, the mirror reflection characteristic of the dichroic mirror 107 is designed to be shorter than the semiconductor light emission intensity distribution of the light emitting diode 106, and depends on the tail of the semiconductor light emission intensity distribution. Therefore, the deep red color is reproduced.

JP 2000-131665 A JP 2002-174854 A JP 2003-255465 A JP 2004-226613 A Japanese Patent Laid-Open No. 2004-226813 JP 2004-29267 A Japanese Patent No. 3640173 JP 2000-305040 A

  In the image display devices disclosed in Patent Documents 2 to 6, the illumination light of the main light source and the illumination light of the sub light source are combined before color separation of the illumination light of the main light source. There is a problem that only the color reproduction of the wavelength band of the sub-light source illumination light can be obtained with respect to the color light to be produced. In addition, since the output of the illumination light from the secondary light source is dominant in the emitted light amount of the combined color light, it is necessary to increase the illumination light output from the secondary light source when attempting to obtain a bright image. It becomes impossible to aim at reduction of.

  In addition, the image display device using the reflection type hologram element as disclosed in Patent Document 7 has problems such as the material cost of the reflection type hologram element and severe optical position accuracy. is not.

  Further, in the image display device disclosed in Patent Document 8 described above, the mirror reflection characteristics of the dichroic mirror 107 used for the synthesis are on the shorter wavelength side than the semiconductor emission intensity distribution and are at the bottom of the semiconductor emission intensity distribution. Designed to be For this reason, although the amount of red light actually increases, the red color of the semiconductor emission spectrum is pulled to the red on the short wavelength side, so that a deep red color reproduction that is expected cannot be obtained. It shifts to an orange that is shallower than the point.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an image display apparatus that enables color reproduction with a wider color gamut and can reduce power consumption by reducing the output load of the laser.

  In solving the above problems, an image display device of the present invention includes a light source that generates white light, a color separation optical system that separates the white light into three wavelength bands of a red band, a green band, and a blue band, An image display apparatus comprising: a spatial modulation element that modulates light in the three wavelength bands to form an image; a red auxiliary light source that generates red monochromatic light; and a red color separated by the color separation optical system A red light combining element for combining the light of the band and the red monochromatic light. The red light combining element is configured to combine the wavelength band in the emission spectral line width of the red monochromatic light and the light of a longer wavelength band. The light is emitted to the spatial modulation element side.

  In the image display device of the present invention, the white light of the light source is color-separated by the color separation optical system, and then the red monochromatic light is synthesized with the color-separated red band light via the red synthesizing element. Therefore, the amount of light in the red wavelength band that is insufficient with the main illumination light is compensated, and the red color of the main illumination light can also be used. As a result, the output load of the red auxiliary light source can be suppressed, and the power consumption can be reduced.

  Further, in the image display device of the present invention, the red combining element emits light in the wavelength band in the emission spectral line width of red monochromatic light and a longer wavelength band to the spatial modulation element side. The chromaticity of red can be deeper than that of red monochromatic light. Thereby, it is possible to express red in a wider color gamut.

  Furthermore, among the separated red light, the wavelength component longer than the wavelength band in the emission spectral line width of the red laser light is used for red expression, so the chromaticity of the extracted red light is the red laser light There is no shift to the shorter wavelength side than the chromaticity point, and a deep red expression is surely obtained.

  Here, as the auxiliary light source for red that generates red monochromatic light, a semiconductor light emitting element such as a semiconductor laser or a light emitting diode is preferably used. In addition, a light emitting element such as an organic or inorganic electroluminescence (EL) element is used. You may use. Further, the wavelength of the red monochromatic light is not particularly limited, and can be appropriately set according to the specification.

  The red synthesizing element can be composed of a dichroic mirror. This dichroic mirror can have an optical characteristic of transmitting a wavelength band in the emission spectral line width of the red monochromatic light from the auxiliary light source and reflecting a longer wavelength band. Alternatively, the opposite optical characteristics may be used.

  On the other hand, in the image display device of the present invention, a blue auxiliary light source for generating blue monochromatic light, and a blue color synthesizing element for synthesizing the blue band light and the blue monochromatic light separated by the color separation optical system are provided. The blue combining element can be configured to emit light of a wavelength band in the emission spectral line width of blue monochromatic light and a shorter wavelength band to the spatial modulation element side. As a result, it is possible to reduce the power consumption by suppressing the output load of the blue auxiliary light source. Further, since the chromaticity of blue can be made deeper than that of blue monochromatic light, blue can be expressed in a wider color gamut.

  As described above, according to the image display device of the present invention, a wider color gamut can be reproduced, and the output load of the auxiliary light source can be suppressed to reduce power consumption.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an image display apparatus 1 according to an embodiment of the present invention. The image display device 1 of the present embodiment is configured as a projection type image display device such as a projector device, and the illumination light emitted from the light source 2 is converted into a red band and a green band by a color separation optical system (16, 17, 23). And the light of each of the three wavelength bands of the blue band, and then the separated color light is modulated by the reflective liquid crystal display panels 3R, 3G, and 3B, which are spatial modulation elements, and a desired color image is displayed on the screen 4 To do.

  Here, the light source 2 is a red auxiliary light source (sub light source) including a main light source 6 composed of a UHP lamp (ultra-high pressure mercury lamp) 5 and a semiconductor laser element 7 that generates red laser light having a predetermined wavelength as red monochromatic light. ) 8 and a blue auxiliary light source (sub light source) 10 including a semiconductor laser element 9 that generates blue laser light having a predetermined wavelength as blue monochromatic light. Although not shown, a UV / IR (ultraviolet / infrared) cut filter is provided on the irradiation surface of the UHP lamp 5, and the illumination optical system is irradiated only with light having a visible wavelength. Yes.

  The main light source 6 causes the substantially white illumination light emitted from the UHP lamp 5 to enter the integrator lens 11 directly or by being reflected by the reflector 6a. The integrator lens 11 is configured by using a pair of fly-eye lenses 11 </ b> A and 11 </ b> B, and makes the light intensity distribution of the main illumination light from the main light source 6 incident on the polarization conversion element 12. The polarization conversion element 12 converts the P-polarized component of the main illumination light emitted from the integrator lens 11 into an S-polarized component and makes it incident on the condenser lens 13. The condenser lens 13 converts the light emitted from the polarization conversion element 12 into light that matches the optical path length of the optical system and emits the light.

  The red auxiliary light source 8 is composed of a heat sink 8a and a semiconductor laser element 7 mounted thereon. The semiconductor laser element 7 emits a laser beam having a wavelength of about 643 nm, which is a red wavelength band, as shown in FIG. The emitted red laser light is converted into a substantially parallel light beam by the collimator lens 14, enters the integrator lens 18 composed of a pair of fly-eye lenses 18 A and 18 B, and is optically reflected by the condenser lens 31 as in the case of the main light source 6. After being converted into a light beam that matches the optical path length of the system, the light beam enters a red composite dichroic mirror 17 described later.

  The blue auxiliary light source 10 includes a heat sink 10a and a semiconductor laser element 9 mounted thereon. The semiconductor laser element 9 emits a laser beam having a wavelength of about 442 nm, which is a blue wavelength band, as shown in an emission spectrum in FIG. The emitted blue laser light is converted into a substantially parallel light beam by the collimator lens 15, enters the integrator lens 19 including a pair of fly-eye lenses 19 A and 19 B, and is optically reflected by the condenser lens 32 as in the case of the main light source 6. After being converted into a light beam according to the optical path length of the system, it is incident on a blue synthetic dichroic mirror 23 described later.

  In the present embodiment in which the red laser beam and the blue laser beam are semiconductor lasers, the divergence angle of the laser beam is large in the vertical direction, so that the collimator lenses 14 and 15 are converted into parallel rays using a cylindrical lens. In the lateral direction, the divergence angle is sufficiently small even when compared with the incident angle of the fly-eye lens, so there is no need to use parallel rays. In addition, the red and blue auxiliary light sources 8 and 10 are set so that the red laser light and the blue laser light are inclined so that they have a polarization plane corresponding to the polarization plane of the main illumination light.

  The main illumination light that has passed through the condenser lens 13 and has a substantially uniform light amount distribution enters the cross dichroic mirror 16. The cross dichroic mirror 16 is configured by combining, for example, the first surface 16A and the second surface 16B having optical characteristics shown in FIGS. 4 and 5 when incident at 45 °, and has a transmittance of 50% centering on a wavelength of 570 nm. Designed to be obtained. Accordingly, the main illumination light incident on the cross dichroic mirror 16 is separated into red light and cyan (blue, green) light with a wavelength of around 570 nm as a boundary.

  The separated red light of the main illumination light enters the red composite dichroic mirror 17. The red composite dichroic mirror 17 corresponds to the “red composite element” of the present invention, and combines the separated red light of the main illumination light and the red laser light generated from the red auxiliary light source 8. Then, the light is emitted to the red reflective liquid crystal display panel 3R side.

  Here, the red composite dichroic mirror 17 is respectively 45 with respect to the red light emission path of the main illumination light separated by the cross dichroic mirror 16 and the red laser light emission path emitted from the red auxiliary light source 8. It is installed with an inclination angle of °. As shown in FIG. 6, the optical characteristic of the red composite dichroic mirror 17 is designed so that a transmittance of 50% is obtained centering on a wavelength of 648 nm when incident at 45 °, and light on the shorter wavelength side is Transmits and reflects light on the long wavelength side. Therefore, light in the wavelength band in the emission spectral line width of the center wavelength of 643 nm of the red laser light is transmitted, and light in the longer wavelength band is reflected, so that the main illumination is emitted on the emission side of the red synthetic dichroic mirror 17. The red light and the red laser light are combined.

  The red light synthesized by the red synthesizing dichroic mirror 17 enters the polarizing beam splitter 21 to which the red reflective liquid crystal display panel 3R is fixed via the lens 20. The polarization beam splitter 21 is formed by bonding prisms, and a light detection surface 21A formed on the bonding surface selectively reflects incident S-polarized red light. The reflected red light is applied to the liquid crystal display panel 3R and spatially modulated. Since the spatially modulated red light becomes P-polarized light, the red light reflected by the liquid crystal display panel 3 </ b> R passes through the light detection surface 21 </ b> A of the polarization beam splitter 21 and then enters the color synthesis prism 29.

  On the other hand, the separated main illumination light cyan (blue, green) light is totally reflected by the mirror 22 that bends the optical path by 90 degrees, and then enters the blue composite dichroic mirror 23. This blue composite dichroic mirror 23 corresponds to the “blue composite element” of the present invention, and combines the separated blue light of the main illumination light and the blue laser light generated from the blue auxiliary light source 10. The light is emitted to the blue reflective liquid crystal display panel 3B side.

  Here, the blue composite dichroic mirror 23 is 45 ° with respect to the cyan light emission path of the main illumination light totally reflected by the mirror 22 and the blue laser light emission path emitted from the blue auxiliary light source 10. It is installed with the inclination angle. As shown in FIG. 7, the optical characteristic of the blue synthetic dichroic mirror 23 is designed so that a transmittance of 50% is obtained centering on a wavelength of 437 nm when incident at 45 °, and light on the longer wavelength side is Transmits light and reflects light on the short wavelength side. Accordingly, light including the wavelength band in the emission spectral line width of the center wavelength of 442 nm of blue laser light and light in the green band are transmitted, and light in a shorter wavelength band is reflected. Thereby, in the blue composite dichroic mirror 23, the cyan light of the main illumination light is separated into the light of the blue band and the light of the green band, and the separated blue band light is emitted from the blue auxiliary light source 10. Synthesized with laser light.

  The blue light synthesized by the blue synthetic dichroic mirror 23 enters the polarization beam splitter 25 to which the blue reflective liquid crystal display panel 3B is fixed via the lens 24. The polarization beam splitter 25 is formed by bonding prisms, and a light detection surface 25A formed on the bonding surface selectively reflects incident S-polarized blue light. The reflected blue light is applied to the liquid crystal display panel 3B and spatially modulated. Since the spatially modulated blue light becomes P-polarized light, the blue light reflected by the liquid crystal display panel 3B passes through the light detection surface 25A of the polarization beam splitter 25 and then enters the color synthesis prism 29.

  Further, the green light (including part of the blue light) of the main illumination light separated by the blue composite dichroic mirror 23 passes through the trimming filter 26, and the green light in a spectral band that can obtain a desired chromaticity is obtained. The light is selectively taken out and enters the polarizing beam splitter 28 to which the green reflective liquid crystal display panel 3G is fixed through the lens 27.

  Here, as shown in FIG. 8, the optical characteristics of the trimming filter 26 are designed so that a transmittance of 50% is obtained centering on a wavelength of 510 nm when incident at 0 °, and light on a longer wavelength side than that is obtained. Transmits and reflects light on the short wavelength side. Accordingly, the light having a wavelength of 510 nm to 570 nm is separated into green light by the optical characteristics of the cross dichroic mirror 16 (second surface 16B) and the trimming filter 26.

  The polarization beam splitter 28 is formed by bonding prisms, and a light detection surface 28A formed on the bonding surface selectively reflects incident S-polarized green light. The reflected green light is applied to the reflective green liquid crystal display panel 3G and spatially modulated. Since the spatially modulated green light becomes P-polarized light, the green light reflected by the liquid crystal display panel 3G passes through the light detection surface 28A of the polarization beam splitter 28 and then enters the color synthesis prism 29.

  Red, green, and blue light modulated by the reflective liquid crystal display panels 3R, 3G, and 3B, which are spatial modulation elements, enter the color synthesis prism 29, are superimposed as an image, and enter and pass through the projection lens 30. Image light is projected onto the screen 4.

  Next, the operation of the image display apparatus 1 of the present embodiment configured as described above will be described.

  The main illumination light emitted from the main light source 6 is made uniform in light quantity distribution by the integrator lens 11, and then the P polarization component is converted into the S polarization component by the polarization conversion element 12. The main illumination light subjected to PS conversion is separated into red light and cyan (blue, green) light by the cross dichroic mirror 16.

  On the other hand, the red laser light having a center wavelength of 643 nm generated from the red auxiliary light source 8 and the blue laser light having a center wavelength of 442 nm generated from the blue auxiliary light source 10 are converted into substantially parallel rays by the collimator lenses 14 and 15. The light enters the red composite dichroic mirror 17 and the blue composite dichroic mirror 23 via the integrator lenses 18 and 19 and the condenser lenses 31 and 32, respectively.

  The red light of the main illumination light separated by the cross dichroic mirror 16 is combined with the red laser light emitted from the red auxiliary light source 8 in the red combining dichroic mirror 17. The synthesized red light enters the red reflective liquid crystal display panel 3R.

  Here, as shown in FIG. 6, the red composite dichroic mirror 17 is designed to transmit the wavelength band in the emission spectral line width of the red laser light and reflect in the longer wavelength band. The chromaticity of red is deeper than that of red laser light. That is, it is possible to express red in a wider color gamut.

  In particular, among the separated red light, the wavelength component longer than the wavelength band in the emission spectral line width of the red laser light is used for red expression, so the chromaticity of the extracted red light is the red laser light There is no shift to the shorter wavelength side than the chromaticity point, and a deep red expression is surely obtained.

  Further, since the main illumination light separated into red light is combined with the red laser light generated by the red auxiliary light source 8, the amount of light in the red wavelength band that is insufficient with the main illumination light is appropriately compensated, Bright images with excellent color reproducibility can be displayed. Further, since the red color of the main illumination light can be used, the output load of the red auxiliary light source 8 can be suppressed, and the power consumption can be reduced.

  On the other hand, the cyan (blue, green) light of the main illumination light separated by the cross dichroic mirror 16 is separated into blue light and green light by the blue composite dichroic mirror 23, and the blue light is separated into the separated blue light. The blue laser light emitted from the auxiliary light source 10 is synthesized. The synthesized blue light is incident on the blue reflective liquid crystal display panel 3B.

  Here, as shown in FIG. 7, the blue synthetic dichroic mirror 23 is designed to transmit the wavelength band in the emission spectral line width of the blue laser light and reflect in the shorter wavelength band. The blue chromaticity is deeper than that of the blue laser light. That is, blue expression in a wider color gamut becomes possible.

  In particular, among the separated blue light, the wavelength component shorter than the wavelength band in the emission spectral line width of the blue laser light is used for blue expression. There is no longer a shift to the longer wavelength side than the chromaticity point, and a deep blue expression is reliably obtained.

  Further, since the main illumination light separated into blue light is combined with the blue laser light generated by the blue auxiliary light source 10, the amount of light in the blue wavelength band that is insufficient with the main illumination light is appropriately compensated, Bright images with excellent color reproducibility can be displayed. Further, since the blue color of the main illumination light can be used, the output load of the blue auxiliary light source 10 can be suppressed, and the power consumption can be reduced.

  In the present embodiment, since the dichroic mirrors 17 and 23 are used for the synthesis of the red light and blue light separated from the main illumination light and the red and blue laser light from the auxiliary light source, the member cost is reduced. Relaxation of component installation accuracy can be achieved.

  The green light of the main illumination light separated by the blue composite dichroic mirror 23 enters the green reflective liquid crystal display panel 3G via the trimming filter 26. According to the present embodiment, the red light and the blue light separated from the main illumination light are supplemented with the laser light of the auxiliary light source, respectively, so that the green light that has been suppressed for white balance can be efficiently obtained. This makes it possible to obtain a brighter image.

  Then, the image light of each color spatially modulated by the liquid crystal display panels 3R, 3G, and 3B is synthesized by the synthesis prism 29 and then projected onto the screen 4 through the projection lens 30. According to the present embodiment, an image with a wide color gamut of red and blue can be displayed, and thus a high-quality display image with excellent color reproducibility can be obtained. In addition, since the amount of emitted light of each color light can be increased and the amount of suppression of green light for white balance can be reduced, a display image with high brightness and high contrast can be obtained. Furthermore, since the output load of the auxiliary light sources 8 and 10 can be suppressed, an image display device with excellent power consumption can be configured.

  FIG. 9 shows that red light and blue light are separated from main illumination light, light having a wavelength longer than 643 nm, light having a wavelength shorter than 442 nm, red laser light having a center wavelength of 643 nm, and center wavelength of 442 nm. The emission spectrum of the illumination light in the case of using only the blue laser beam is shown. When the chromaticity in this case is calculated, red: R (x = 0.721, y = 0.278), green: G (x = 0.289, y = 0.697), blue: B (x = 0) .163, y = 0.012), and the NTSC area ratio is about 110.3%.

  In the example of FIG. 9, assuming that the illumination efficiency of each color is 15% and the chromaticity point of white is 10000K, the light output of each light source is red: R = 4 [W], green: G = 4.2 [W], blue: When B = 4 [W], the total luminous flux is about 480 [lm (lumen)]. That is, the output of both the red laser and the blue laser needs 4 [W].

  On the other hand, the emission spectrum of the illumination light in the embodiment of the present invention described above is shown in FIG. 11 is a chromaticity diagram, and FIG. 12 is an emission spectrum of the UHP lamp 5, red laser light, and blue laser light, and also shows optical characteristics of the dichroic mirrors 16, 17, 23, and the trimming filter 26. .

  In the example of FIG. 10, the chromaticity of the illumination light was calculated. In the calculation, red laser light having a center wavelength of 643 nm and light having a wavelength longer than at least 643 nm separated from the main illumination light emitted from the UHP lamp 5 and blue light having a center wavelength of 442 nm are used as red light. Cross dichroic in the blue laser light, the light having a wavelength shorter than the wavelength 442 nm separated from the main illumination light emitted from the UHP lamp 5, and the main illumination light emitted from the UHP lamp 5 as green light Lights separated into wavelengths of 510 to 570 nm by the optical characteristics of the mirror 16 and the trimming filter 26 were used, respectively. As a result of the calculation, red: R (x = 0.722, y = 0.278), green: G (x = 0.289, y = 0.597), blue: B (x = 0.164, y = 0.011). Further, the NTSC area ratio was about 110.5%, and it was confirmed that the color gamut was expanded by 0.2% compared to the example of FIG.

  In the example of FIG. 10, assuming that the illumination efficiency of each color is 15% and the white chromaticity point is 10000K, the respective light sources are red: R = 4 [W], green: G = 4.2. [W], blue: When B = 4 [W], the total luminous flux is about 480 [lm (lumen)]. At this time, the output of the red laser light and the blue laser light is subtracted by the light having a wavelength longer than 643 nm and the light having a wavelength shorter than 442 nm separated from the UHP lamp as the main light source. Output is 3.48 [W], the output of blue laser light is 2.96 [W], 0.52 [W] for red, and 1.04 [W] for blue, the load on the laser Can be reduced respectively.

  The embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made based on the technical idea of the present invention.

  For example, in the above embodiment, the dichroic mirror 17 that transmits the wavelength band in the emission spectral line width of the red laser light and reflects the longer wavelength band is used as the red combining element. Accordingly, a dichroic mirror that reflects the opposite optical characteristics, that is, the wavelength band in the emission spectral line width of the red laser light and transmits the longer wavelength band may be used. Similarly, a dichroic mirror that reflects a wavelength band in the emission spectral line width of blue laser light and transmits a shorter wavelength band may be used as the blue combining element.

  In the above embodiment, the secondary illumination light from the red auxiliary light source 8 and the blue auxiliary light source 10 is combined with respect to red and blue. However, only the red illumination light is combined with the secondary illumination light to increase the amount of emitted light. You may make it show.

  In the above embodiment, the trimming filter 26 is used to adjust the chromaticity and light amount of green, but the white balance is adjusted not only for green light but also for blue and red using the same trimming filter. May be performed.

  In the above embodiment, the polarization beam splitters 21, 25, and 28 are used. However, instead of this, a wire grid polarizer may be used. The spatial modulation element is not limited to the reflective liquid crystal display panels 3R, 3G, and 3B, but may be an optical system using a transmissive liquid crystal display panel or a DMD (digital micromirror device).

1 is a schematic configuration diagram of an image display device according to an embodiment of the present invention. It is a figure which shows the emission spectrum of the red laser beam radiate | emitted from the auxiliary light source for red in embodiment of this invention. It is a figure which shows the emission spectrum of the blue laser beam radiate | emitted from the auxiliary light source for blue in embodiment of this invention. It is a figure which shows the optical characteristic of the cross dichroic mirror which comprises the color separation optical system in embodiment of this invention. It is a figure which shows the optical characteristic of the cross dichroic mirror which comprises the color separation optical system in embodiment of this invention. It is a figure which shows the optical characteristic of the synthetic | combination dichroic mirror for red in embodiment of this invention. It is a figure which shows the optical characteristic of the synthetic | combination dichroic mirror for blue in embodiment of this invention. It is a figure which shows the optical characteristic of the trimming filter for green in embodiment of this invention. It is a figure which shows the spectrum of the illumination light which used only the red laser beam shown in FIG.2, 3 and the blue laser beam for red and blue using the light of wavelength 510-570nm isolate | separated from the illumination light of the UHP lamp for green. . Light having a wavelength of 510 to 570 nm separated from the illumination light of the UHP lamp is used for green, and light having a wavelength longer than that of the red laser light illustrated in FIG. 2 and the red laser light separated from the UHP lamp is used for red. It is a figure which shows the spectrum of the illumination light using the light which combined and used the blue laser beam shown in FIG. 3 in blue and the light of a wavelength shorter than the said blue laser beam isolate | separated from the UHP lamp. It is a chromaticity diagram of the illumination light shown in FIG. It is a figure which shows the optical characteristic of the emission spectrum of a UHP lamp, a red laser beam, and a blue laser beam in embodiment of this invention, a dichroic mirror, and a trimming filter. It is a figure which shows an example of the emission spectrum of a UHP lamp. It is a schematic block diagram of the conventional image display apparatus. It is a figure which shows the optical characteristic of the dichroic mirror for red composition in the prior art example shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Image display apparatus, 2 ... Light source, 3R, 3G, 3B ... Reflective type liquid crystal display panel (spatial modulation element), 4 ... Screen, 5 ... UHP lamp, 6 ... Main light source, 8 ... Red auxiliary light source, 10 ... Auxiliary light source for blue, 16 ... cross dichroic mirror, 17 ... composite dichroic mirror for red (composite element for red), 23 ... composite dichroic mirror for blue (composite element for blue), 29 ... color synthesis prism, 30 ... projection lens

Claims (6)

A light source that generates white light;
A color separation optical system that separates the white light into three wavelength bands, a red band, a green band, and a blue band;
An image display device comprising: a spatial modulation element that modulates light of the three wavelength bands to form an image;
An auxiliary light source for red that emits red monochromatic light;
A red combining element that combines the red band light separated by the color separation optical system and the red monochromatic light;
The image display device, wherein the red combining element emits light having a wavelength band in an emission spectrum line width of the red monochromatic light and a wavelength band longer than the wavelength band to the spatial modulation element side. 2. The image display device according to claim 1, wherein the red combining element is a dichroic mirror that transmits a wavelength band in an emission spectral line width of the red monochromatic light and reflects a longer wavelength band. . 2. The image display device according to claim 1, wherein the red synthesizing element is a dichroic mirror that reflects a wavelength band in an emission spectral line width of the red monochromatic light and transmits a longer wavelength band. . A blue auxiliary light source for generating blue monochromatic light;
Further comprising a blue combining element that combines the blue band light separated by the color separation optical system and the blue monochromatic light,
2. The image according to claim 1, wherein the blue combining element emits light having a wavelength band in an emission spectrum line width of the blue monochromatic light and a wavelength band shorter than the wavelength band to the spatial modulation element side. Display device. The image display device according to claim 4, wherein the blue combining element is a dichroic mirror that transmits a wavelength band in an emission spectrum line width of the blue monochromatic light and reflects a shorter wavelength band. . The image display device according to claim 4, wherein the blue combining element is a dichroic mirror that reflects a wavelength band in an emission spectral line width of the blue monochromatic light and transmits a shorter wavelength band. .

Images