JP2005115179A - Image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize an image display device of a projection type which performs color display with a small size. <P>SOLUTION: The image display device of the projection type has an illuminator including a light source 1, an optical modulation element 22 for modulating the illumination light from the illuminator in accordance with a video signal, and a projection lens 15 for forming the image of the optical modulation element 22. The illuminator is equipped with an illumination light separating means 21 which emits the luminous fluxes of the respective wavelength bands varying from each other from respectively spatially different regions and an optical component 6 which converts the luminous fluxes of the respective wavelength bands from the illumination light separating means 21 to the luminous fluxes of respectively different angle distributions and makes the luminous fluxes incident on the optical modulation element 22. The optical modulation element 22 is provided with a microlens array which condenses the luminous fluxes of the respective wavelength bands respectively varying in the incident angle distributions from the optical component 6 to respectively corresponding pixels. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a projection-type image display device, and more particularly, to a compact image display device that can perform color display.

  2. Description of the Related Art Conventionally, there has been proposed a projection-type image display device including an illumination device including a light source, a light modulation element illuminated by the illumination device, and a projection lens that forms an image of the light modulation element. Among these, there is a liquid crystal projector that uses a discharge lamp as a light source and a liquid crystal panel as a light modulation element.

  Since many liquid crystal projectors have three liquid crystal panels for R, G, and B, many optical components such as a light separating means such as a dichroic mirror and a light synthesizing means such as a cross prism are necessary. And cost reduction are difficult. In addition, since the balance of the light amounts of R, G, and B of the light source is not necessarily appropriate, a part of the light beam cannot be used to adjust the color balance, so the light beam can always be used effectively. It wasn't.

  As a method for realizing a liquid crystal projector for color display with a single plate, there is also a method using a liquid crystal panel with a color filter. However, in this method, about 2/3 of the light is absorbed or reflected by the color filter. For example, in a color filter that transmits the red wavelength band, light in the green and blue wavelength bands cannot illuminate the light modulation element. Therefore, the luminous flux cannot be used effectively.

  Another method is to separate R, G, and B into different angle components using a dichroic mirror immediately before entering the liquid crystal panel, and enter the liquid crystal panel with a microlens so that the color can be obtained on a single plate. There is also a method for realizing the display (for example, see Patent Document 1).

On the other hand, among the light beams emitted from the light source, a method of increasing the light utilization efficiency by returning the light beam to be illuminated to the light modulation element to the light source by the first reflection element and returning the light modulation element to the light modulation element again by the second reflection element. Is disclosed (for example, see Patent Document 2).
Japanese Patent No. 2622185 (pages 3-5, FIGS. 1-2) JP 2002-328430 A (paragraph numbers 0039 to 0048, FIGS. 3 to 5 and the like)

  However, the method as described in Patent Document 1 requires a plurality of dichroic mirrors to separate the light flux, and the apparatus becomes complicated. In addition, in a plurality of pixels condensed by one microlens, a complicated pixel arrangement structure (for example, FIG. 12A and FIG. Realization of a pixel arrangement structure such as 12 (b) is difficult in design.

  In addition, this Patent Document 2 describes that the light use efficiency is improved by using a device that selects and reflects a specific polarized light as a first reflection element or a device that reflects a light beam in a light modulation element. However, there is no description of a configuration that is small and performs color display.

  In view of the above-described points, the present invention has been made to realize a small-sized projection-type image display device that performs color display.

  In order to solve this problem, the applicant of the present invention has disclosed an illumination device including a light source, a light modulation element that modulates illumination light from the illumination device according to a video signal, and a projection lens that forms an image of the light modulation element. In the projection type image display apparatus having the above, the illuminating device includes illumination light separating means for emitting light beams of mutually different wavelength bands from spatially different regions, and light beams of each wavelength band from the illumination light separating means. An optical component that converts the luminous flux into a light modulator having different angular distributions and makes the light modulator enter the light modulating element. An image display apparatus provided with a microlens array for condensing light is proposed.

  According to this image display device, light beams in respective wavelength bands emitted from spatially different regions are converted into light beams having different angular distributions and are incident on the light modulation element (in other words, in each wavelength band). The position information of the light beam is converted into information on the incident angle to the light modulation element), and is condensed on the corresponding pixels by the microlens array. Accordingly, since color display can be performed even with a single light modulation element without a color filter, it is possible to realize a projection-type image display device that performs color display in a small size.

  In this image display device, as an example, the illuminating device further includes a reflector that reflects light from the light source and outputs the reflected light to the light modulation element, and the illuminating light separating means has a predetermined wavelength of the light flux from the light source. An optical component that transmits a light beam in a band, reflects a light beam in another wavelength band, and returns it to the reflector. The optical component is divided into a plurality of regions, and the transmitted wavelength band is composed of different optical components in each region. It is preferable to do.

  As a result, the luminous flux that does not pass through the individual areas of the illumination light separating means is reflected by the area and the reflector, returns to the light source, then reflected again by the reflector, and passes through another area of the illumination light separating means. It enters the light modulation element. Therefore, it is possible to realize a projection-type image display device that not only performs small-sized color display but also has low cost and high light utilization efficiency.

  In the case where the illumination light separating means is composed of such optical components, as an example, the illumination light separating means is divided into three regions in a stripe shape, and the central region is a wavelength band having a high intensity of the light flux from the light source. It is preferable that both end regions transmit a wavelength band having a low intensity among the light beams from the light source.

  Most of the light beam reflected in the central region is reflected by the reflector, and most of the light returns again to the central region of the illumination light separating means. Therefore, reflection is repeated again, and the reuse efficiency is not so high. On the other hand, the light beam reflected by the individual end regions of the illumination light separating means returns to the other end region of the illumination light separating means after being reflected by the reflector, so that a transmitted light beam is generated and the reuse efficiency is improved. Get higher. Therefore, by adopting such a configuration, it becomes possible to realize a projection-type image display device in which the light use efficiency is high and the color balance is adjusted.

  Further, in the case where the illumination light separating means is composed of such optical components, as another example, the illumination light separating means is transmitted through the red wavelength band, the green wavelength band, and the blue wavelength band. And a pixel that displays red corresponding to the area of the illumination light separating means on the light modulation element, and is configured to be divided into a yellow wavelength band or a region that transmits all visible light wavelength bands, It is also preferable to provide pixels that display green, pixels that display blue, and pixels that display yellow or white.

  As a result, it is possible to realize a projection type image display device with a multi-light source of four or more colors with a simple configuration, and to realize a projection type image display device with a wide color reproduction area and high light utilization efficiency. It becomes like this.

  When the illumination light separating means is composed of such optical components, as another example, the illumination light separating means is divided into five or more regions, and the region that transmits the blue wavelength band transmits the other wavelength band. The number of light modulation elements corresponding to the area of the illumination light separating means is smaller than the number of pixels displaying other colors. Such a configuration is also suitable.

  In general, the human eye has a lower resolving power than the other colors in the blue wavelength region. Therefore, by adopting such a configuration, a low-cost and high-resolution projection-type image display device can be realized.

  Further, in the case where the illumination light separating means is composed of such optical components, as another example, the illumination light separating means is divided into two regions and configured to transmit two wavelength bands in at least one region. It is also preferable that two light modulation elements are provided, and at least one light modulation element is provided with a microlens array for condensing light beams of two wavelength bands on the corresponding pixels.

  Even in such a configuration, for example, one light modulation element for displaying two of R, G, and B colors and one light modulation element for displaying only the remaining one color Color display can be performed with a total of two light modulation elements. Therefore, compared with the case where three light modulation elements for R, G, and B are provided, it is still possible to perform color display in a small size, and to realize a projection type image display device with high light utilization efficiency at low cost. become able to. Furthermore, when the intensity of the luminous flux from the discharge lamp is biased depending on the wavelength band, only one color having the lowest intensity is displayed by one light modulation element, so that the light use efficiency is high and the color balance is adjusted. The projection type image display device can be realized.

  According to the present invention, there is an effect that a projection-type image display device that performs small color display can be realized.

  Further, not only a small color display but also an effect that a projection type image display device with low cost and high light utilization efficiency can be realized.

  In addition, it is possible to realize a projection-type image display device that has high light use efficiency and is adjusted in color balance.

  Furthermore, it is possible to obtain a projection-type image display device that has a simple configuration, a wide color reproduction area, and high light utilization efficiency.

  Furthermore, the effect that a low-cost and high-resolution projection-type image display apparatus can be realized is also obtained.

  Hereinafter, an example in which the present invention is applied to a liquid crystal projector will be specifically described with reference to the drawings.

First, a two-plate liquid crystal projector that performs color display with two transmissive liquid crystal panels will be described.
<Configuration>
FIG. 1 shows an optical system of a two-plate liquid crystal projector according to the present invention. This optical system includes a discharge lamp 1 as a light source, a parabolic reflector 2 that reflects light emitted from the discharge lamp 1, a first fly-eye lens 3, a second fly-eye lens 4, and a dichroic filter 16. A PS converter (an optical component comprising a polarizing beam splitter and a half-wave plate) for converting incident light into specific linearly polarized light, a condenser lens 6, a dichroic mirror 7, reflection mirrors 8 and 9, The field lenses 10 and 12, the transmissive liquid crystal panels 11 and 13, the color synthesis prism 14, and the projection lens 15 are formed.

  The light beam emitted from the discharge lamp 1 becomes substantially parallel light by the reflector 2 and enters the first fly-eye lens 3 and the second fly-eye lens 4. The fly-eye lenses 3 and 4 make the spatial distribution of the incident light beam uniform. The light beam that has passed through the second fly-eye lens 4 enters the dichroic filter 16. The dichroic filter 16 is light from the discharge lamp 1 in a position substantially conjugate with the light emitting region formed between the two electrodes of the discharge lamp 1, that is, in the optical path of illumination light that illuminates the transmissive liquid crystal panels 11 and 13. Are condensed by the individual lens elements of the first fly-eye lens 3 via the reflector 2 and are arranged in the vicinity of a conjugate point where an image of the discharge lamp 1 is formed. As shown in FIG. 2A, the dichroic filter 16 has a structure divided into two regions 16Y and 16M. The region 16Y transmits light in the red and green wavelength bands and reflects light in the blue wavelength band. On the other hand, the region 16M transmits light in the red and blue wavelength bands and reflects the green wavelength band.

  As shown in FIG. 3, the light beam reflected by the dichroic filter 16 passes through the second fly-eye lens 4 and the first fly-eye lens 3, is reflected by the reflector 2, and is between the two electrodes of the discharge lamp 1. Return to the light emitting area to be formed. Then, after passing between the electrodes, it is reflected by the reflector 2, passes through the first fly-eye lens 3 and the second fly-eye lens 4 again, and enters the dichroic filter 16. From this recycling process, the light in the blue wavelength band reflected by the region 16Y of the dichroic filter 16 (FIG. 2A) re-enters the region 16M, passes through the dichroic filter 16, and reflects the light in the green wavelength band reflected by the region 16M. The light re-enters the region 16Y and passes through the dichroic filter 16.

  Through the above process, of the light emitted from the discharge lamp 1, red light is emitted from the entire surface of the dichroic filter 16, green light is emitted only from the region 16Y of the dichroic filter 16, and blue light is emitted from only the region 16M of the dichroic filter 16. It will be emitted from.

  The light that has passed through the dichroic filter 16 is converted into specific linearly polarized light (linearly polarized light that passes through the polarizing plate on the incident surface side of the liquid crystal panels 11 and 13) by the PS converter 5 in FIG. FIG. 4 shows the optical path of the luminous flux in the red wavelength band after passing through the dichroic filter 16. The red band light beam emitted from the entire surface of the dichroic filter 16 passes through the condenser lens 6 via the PS converter 5 and enters the dichroic mirror 7. The dichroic mirror 7 is a mirror that reflects the red wavelength band and transmits the green wavelength band and the blue wavelength band, and the light beam in the red band is reflected here. Thereafter, the liquid crystal panel 11 is illuminated after being further reflected by the reflection mirror 9 and transmitted through the field lens 10. Although not shown, the liquid crystal panel 11 is formed with pixels for red display.

  FIG. 5 shows the optical paths of the light beams in the green wavelength band and the blue wavelength band after passing through the dichroic filter 16. Since the dichroic filter 16 is divided into two regions 16Y and 16M (FIG. 2A), the light beams in the green wavelength band and the blue wavelength band are emitted from regions spatially different from each other. After passing through the PS converter 5 and passing through the condenser lens 6, these light beams become light beams having different angle components in the green wavelength band and the blue wavelength band. In other words, the position information of the light beams in the green wavelength band and the blue wavelength band from the dichroic filter 16 is converted into angle information by the condenser lens 6.

  The light beams in the green wavelength band and the blue wavelength band that have passed through the condenser lens 6 pass through the dichroic mirror 7, are reflected by the reflection mirror 8, pass through the field lens 12, and then illuminate the liquid crystal panel 13.

  FIG. 6 is a diagram schematically showing the configuration of the liquid crystal panel 13. As shown in FIG. 6A, the liquid crystal panel 13 is provided with a microlens array in which a plurality of microlenses 101 are arranged on a counter substrate 102 on the light irradiation surface side. In the liquid crystal layer 103 of the liquid crystal panel 13, pixels 104G for green display and pixels 104B for blue display are alternately arranged. One micro lens 101 corresponds to one set of pixels 104G and 104B. FIG. 6B shows a state in which the one set of pixels 104G and 104B is viewed from above the microlens 101.

  As described with reference to FIG. 5, the luminous flux that illuminates the liquid crystal panel 13 has different incident angle distributions on the liquid crystal panel 13 in the blue wavelength band and the green wavelength band. Therefore, as shown in FIG. 6A, the light in the blue wavelength band is collected by the microlens 101 and enters the pixel 104B, and the light in the green wavelength band is collected by the microlens 101 and enters the pixel 104G. Will do.

  Drive voltages corresponding to the R, G, and B signals are applied to the pixels of the liquid crystal panel 11, the pixels 104G of the liquid crystal panel 13, and the pixels 104B of the liquid crystal panel 13, respectively. Then, as shown in FIG. 1, the light flux in the red wavelength band modulated by the liquid crystal panel 11 and the light flux in the green and blue wavelength bands modulated by the liquid crystal panel 13 are synthesized by the color synthesis prism 14 and are projected into the projection lens. 15 is projected onto a screen (not shown).

  When this two-plate type liquid crystal projector is compared with a normal three-plate type liquid crystal projector, the light use efficiency is substantially the same in the red wavelength region.

  On the other hand, for the green and blue wavelength regions, the recycled light utilization rate (the ratio of the luminous flux reflected by the dichroic filter 16 and re-incident between the electrodes of the discharge lamp 1 and then incident on the first fly-eye lens 3 again) If the probability that a light beam reflected at least once by the dichroic filter 16 is incident on and transmitted through the dichroic filter 16 again is 100%, the light utilization efficiency is equivalent to that of a normal three-plate liquid crystal projector. It does not become so large under the influence of general manufacturing error, scattering by the electrode of the discharge lamp 1, etc., for example, about 35 to 40%. However, an ultra-high pressure mercury lamp generally used as a light source has many green and blue wavelength band components with respect to the red wavelength band component. Therefore, considering the balance of colors, the previous green and blue wavelength band components There is no problem with the decrease. That is, according to the present invention, it is possible to achieve downsizing of the apparatus and cost reduction by reducing the number of components without causing deterioration of light utilization efficiency and image deterioration.

<Other configuration examples of the dichroic filter 16 and the liquid crystal panel 13>
As described above, in many projection-type image display apparatuses, an ultrahigh pressure mercury lamp is used as a light source. Considering the color balance as illumination light for the image display device, this lamp has a relatively large green wavelength band component, and then continues in blue and red.

  Considering these relationships, another configuration example of the dichroic filter 16 includes reducing the area of the region 16Y with respect to the region 16M as shown in FIG. Also in this case, as in the previous example, the red wavelength band component, the green wavelength band component incident on the region 16Y, and the blue wavelength band component incident on the region 16M pass through the dichroic filter 16, but enter the region 16Y. The blue wavelength band component and the green wavelength band component incident on the region 16M are reflected, return between the electrodes of the discharge lamp 1, and again enter the first fly-eye lens 3 (FIG. 3). Therefore, as the optical path after passing through the dichroic filter 16, the red wavelength band is as shown in FIG. The green wavelength band and the blue wavelength band have different angle components with respect to the optical axis, as shown in FIG.

  FIG. 8 is a diagram showing the configuration of the liquid crystal panel 13 in this case in the same manner as FIG. The liquid crystal panel 13 reduces the area of the pixel 104G relative to the pixel 104B in accordance with the area ratio between the region 16M and the region 16Y of the dichroic filter 16. Thereby, the light of a blue wavelength band component can be utilized more efficiently. Moreover, since the red wavelength component can still use the entire surface of the liquid crystal panel 11, the light utilization efficiency is further increased. As a result, since a color with a small amount of light can be used more efficiently, the overall light use efficiency can be increased.

Next, a single-plate liquid crystal projector that performs color display with a single transmissive liquid crystal panel will be described.
<Configuration>
FIG. 9 is a diagram showing an optical system of a single-plate type liquid crystal projector according to the present invention, and the same reference numerals are given to portions common to FIG. This optical system includes a discharge lamp 1 that is a light source, a parabolic reflector 2 that reflects light emitted from the discharge lamp 1, a first fly-eye lens 3, a second fly-eye lens 4, and a dichroic filter 21. , PS converter 5, condenser lens 6, field lens 10, transmissive liquid crystal panel 22, and projection lens 15. The dichroic filter 21 is disposed at a position conjugate with the light emitting part of the discharge lamp 1.

  The light beam emitted from the discharge lamp 1 becomes substantially parallel light by the reflector 2 and enters the first fly-eye lens 3 and the second fly-eye lens 4. The fly-eye lenses 3 and 4 make the spatial distribution of the incident light beam uniform. The light beam that has passed through the second fly-eye lens 4 enters the dichroic filter 21. As shown in FIG. 10A, the dichroic filter 21 has a structure divided into three regions 21R, 21G, and 21B. The region 21R transmits the red wavelength band and reflects other wavelength bands. The region 21G transmits the green wavelength band and reflects other wavelength bands. The region 21B transmits the blue wavelength band and reflects other wavelength bands.

  In FIG. 9, the light beam reflected by the dichroic filter 21 passes through the second fly-eye lens 4 and the first fly-eye lens 3 and returns to the light emitting part of the discharge lamp 1. Then, after passing between the electrodes of the discharge lamp 1, it is reflected by the reflector 2, passes through the first fly-eye lens 3 and the second fly-eye lens 4 again, and enters the dichroic filter 21.

  Through this recycling process, most of the light in the green wavelength band and the blue wavelength band reflected by the region 21R at one end of the dichroic filter 21 reenters the region 21B at the other end of the dichroic filter 21, Only light passes through the dichroic filter 21.

  Similarly, most of the light in the green wavelength band and the red wavelength band reflected by the region 21 </ b> B of the dichroic filter 21 reenters the region 21 </ b> R, and only the light in the red wavelength band passes through the dichroic filter 21.

  Further, part of the light in the red wavelength band and the blue wavelength band reflected by the central region 21G of the dichroic filter 21 is incident again on the region 21R and the region 21B and passes through the dichroic filter 21.

  Through the above process, while improving the light utilization efficiency, the light beam in the red wavelength band is emitted only from the region 21R of the dichroic filter 21, and the light beam in the green wavelength band is emitted only from the region 21G of the dichroic filter 21. The luminous flux is emitted only from the region 21B of the dichroic filter 21. In addition, since the efficiency of using light in the red wavelength band and blue wavelength band is higher than in the green wavelength band, the color balance is also reduced when using an ultra-high pressure mercury lamp with a relatively large green wavelength band component as described above. Can be adjusted.

  As shown in FIG. 9, the light beams in the red wavelength band, the green wavelength band, and the blue wavelength band respectively transmitted through the regions 21R, 21G, and 21B of the dichroic filter 21 pass through the condenser lens 6 after passing through the PS converter 5. Thus, the light beams have different angle components in the red wavelength band, the green wavelength band, and the blue wavelength band. In other words, the position information of the light flux in the red wavelength band, the green wavelength band, and the blue wavelength band from the dichroic filter 21 is converted into angle information by the condenser lens 6.

  The red, green, and blue wavelength light fluxes that have passed through the condenser lens 6 pass through the field lens 10 and then illuminate the liquid crystal panel 22.

  FIG. 11 is a diagram schematically illustrating the configuration of the liquid crystal panel 22, and the same reference numerals are given to portions common to FIG. 6. As shown in FIG. 11A, in the liquid crystal panel 22, a microlens array in which a plurality of microlenses 101 are arranged is provided on a counter substrate 102 on the light irradiation surface side. In the liquid crystal layer 103 of the liquid crystal panel 13, red display pixels 105R, green display pixels 105G, and blue display pixels 105B are alternately arranged. One microlens 101 corresponds to one set of pixels 105R, 105G, and 105B. FIG. 11B shows a state in which the one set of pixels 105 </ b> R, 105 </ b> G, and 105 </ b> B is viewed from above the microlens 101.

  As described with reference to FIG. 9, the luminous flux that illuminates the liquid crystal panel 22 has different incident angle distributions on the liquid crystal panel 22 in the red wavelength band, the blue wavelength band, and the green wavelength band. Therefore, as shown in FIG. 11A, the light in the red wavelength band is collected by the microlens 101 and enters the pixel 105R, and the light in the blue wavelength band is collected by the microlens 101 and enters the pixel 105B. The light in the green wavelength band is collected by the microlens 101 and enters the pixel 105G.

  Driving voltages corresponding to R, G, and B signals are applied to the pixels 105R, 105G, and 105B of the liquid crystal panel 22, respectively. Then, as shown in FIG. 9, the luminous fluxes of the red wavelength band, the green red wavelength band, and the blue wavelength band modulated by the liquid crystal panel 22 are projected onto a screen (not shown) by the projection lens 15.

<Other configuration examples of the dichroic filter 21 and the liquid crystal panel 22>
In general, since the human eye has a lower resolution in the blue wavelength region than other colors, it can display a fine image even if the number of pixels is reduced with respect to the wavelength bands of other colors. ((Reference: PenTile Matrix http://www.pentile.com) Therefore, as shown in FIG. 12A and FIG. 12B, as another configuration example of the dichroic filter 21, the number of divisions of the region 21B It is conceivable to increase the number of divisions of the regions 21R and 21G as compared with the above.

  FIGS. 13A and 13B are views showing the pixel structure of the liquid crystal panel 22 in the case of FIGS. 12A and 12B, respectively, as in FIG. 11B. Corresponding to the number and area of the regions 21R, 21G, and 21B of the dichroic filter 21, the number of the pixels 105B is made smaller than those of the pixels 105R and 105G, and the area of the pixel 105B is made larger than those of the pixels 105R and 105G. By adopting such a configuration, it is possible to realize a single-plate liquid crystal projector with high definition and low cost.

  As another configuration example of the dichroic filter 21, as shown in FIG. 12C, in addition to the regions 21R, 21G, and 21B, a region 21Y that transmits only the yellow wavelength band and reflects other wavelength bands is provided. It is conceivable to provide it. FIG. 13C is a diagram showing the pixel structure of the liquid crystal panel 22 in this case in the same manner as FIG. Corresponding to the regions 21R, 21G, 21B, and 21Y of the dichroic filter 21, pixels 105R, 105G, 105B, and 105Y are provided, respectively.

  Further, as a similar example, as shown in FIG. 12D, it is conceivable to provide a region 21W that transmits all visible light wavelength bands instead of the region 21Y in FIG. FIG. 13D is a diagram showing the pixel structure of the liquid crystal panel 22 in this case in the same manner as FIG. Corresponding to the regions 21R, 21G, 21B, and 21W of the dichroic filter 21, pixels 105R, 105G, 105B, and 105W are provided, respectively.

  In a general liquid crystal projector, when the color reproduction area is widened, the light use efficiency is deteriorated. Conversely, when the light use efficiency is increased, the color reproduction area tends to be narrowed. However, when the configurations of FIGS. 12C and 13C and the configurations of FIGS. 12D and 13D are taken, the color purity of R, G, and B is good and the light utilization efficiency is high. A high-performance LCD projector can be realized.

Next, a single-plate liquid crystal projector that performs color display using a single transmissive liquid crystal panel, which uses a rod integrator instead of the first fly-eye lens and the second fly-eye lens, will be described.
<Configuration>
FIG. 14 is a diagram showing an optical system of such a single-plate liquid crystal projector, and the same reference numerals are given to the portions common to FIG. The optical system includes a discharge lamp 1 that is a light source, an elliptical reflector 202 that reflects light emitted from the discharge lamp 1, a rod integrator 203, a dichroic filter 21, a condenser lens 6, a field lens 10, and a transmission. The liquid crystal panel 22 and the projection lens 15 are formed. The dichroic filter 21 is disposed at a position conjugate with the light emitting part of the discharge lamp 1.

  The light beam emitted from the discharge lamp 1 is collected by the reflector 202 and enters the rod integrator 203. A PS converter including a PBS 204 and a half-wave plate 205 is provided on the front surface of the rod integrator 203. The light beam incident on the rod integrator 203 is converted into specific linearly polarized light by the PS converter, and then the reflection is repeated in the rod integrator 203 so that the intensity distribution is uniformed, and is emitted from the rod integrator 203 to be emitted from the dichroic filter. 21 is incident.

  As shown in FIG. 10A, the dichroic filter 21 has a structure divided into three regions 21R, 21G, and 21B. As described in the second embodiment, the dichroic filter 21 increases red light efficiency while increasing the light utilization efficiency. Light beams in the wavelength band, the green wavelength band, and the blue wavelength band are emitted only from the regions 21R, 21G, and 21B of the dichroic filter 21, respectively, and the color balance can be adjusted.

  As shown in FIG. 14, the light beams in the red wavelength band, green wavelength band, and blue wavelength band that have transmitted through the regions 21R, 21G, and 21B of the dichroic filter 21 are transmitted through the condenser lens 6, so that the red wavelength band and the green wavelength band are green. The light beams have different angle components in the wavelength band and the blue wavelength band. The red, green, and blue wavelength light fluxes that have passed through the condenser lens 6 pass through the field lens 10 and then illuminate the liquid crystal panel 22.

  The liquid crystal panel 22 has a configuration as shown in FIG. 11, and as a result, light in the red wavelength band, blue wavelength band, and green wavelength band is condensed by the microlens 101 to the pixels 105R, 105G, and 15B. Incident. The light flux in the red wavelength band, green red wavelength band, and blue wavelength band modulated according to the R, G, and B signals by the liquid crystal panel 22 is screened (not shown) by the projection lens 15 as shown in FIG. Projected on top.

Finally, some modified examples common to two or more of the first to third embodiments will be described.
<Examples of changing dichroic filters and fly-eye lenses>
First, a modified example of the configuration of the dichroic filter and the fly-eye lens will be described. Each of the dichroic filters described in the first to third embodiments is divided into a plurality of regions, and each region is arranged without a gap. For example, FIG. 15A shows the dichroic filter 21 of FIG. 12D again, but the regions 21R, 21G, 21B, and 21W are arranged without gaps. However, the light beam that has passed through, for example, the region A in the vicinity of the boundary between the regions 21R and 21G in the dichroic filter 21 is a region between the pixels 105R and 105G of the liquid crystal panel 22 as shown in FIG. (Area such as signal electrode) Since A ′ is illuminated, the luminous flux is wasted.

  Therefore, as shown in FIG. 15B, a mirror 23 that reflects the visible light wavelength band is formed between the regions 21R, 21G, 21B, and 21W of the dichroic filter 21. As a result, the light beam reflected by the mirror 23 returns to the discharge lamp 1, and some of the light re-enters the regions 21 R, 21 G, 21 B, and 21 W, so that the pixel region of the liquid crystal panel 22 is illuminated.

  As described above, the light utilization efficiency can be further increased by reflecting the light beam incident on the area where there is no pixel on the liquid crystal panel by the dichroic filter in advance and entering the area where the pixel is present.

  Further, in Example 2, as shown in FIG. 16 (a), the second fly-eye lens 4 out of the first fly-eye lens 3 and the second fly-eye lens 4 (FIG. 9) is replaced with FIG. The lens 4a at the position corresponding to the mirror 23 of the dichroic filter 21 is made smaller than the other lenses. As a result, as shown in FIG. 16B, the first fly-eye lens 3 is larger than the incident angle θ1 of light that enters the lens 3a of the first fly-eye lens 3 corresponding to the lens 4a and then reaches the lens 4a. The incident angle θ2 of light reaching the corresponding lens of the second fly's eye lens 4 after entering the other lens becomes larger.

  As a result, out of the luminous flux emitted from the second fly-eye lens 4, it enters the regions 21R, 21G, 21B, and 21W of the dichroic filter 21 (FIG. 15B) and enters the liquid crystal panel 22 (FIG. 15C). Since the ratio of the light beam incident on the pixel area is further increased and the ratio of the light beam incident on the inter-pixel area such as the area A ′ is decreased, the light use efficiency can be further increased.

  Here, the dichroic filter 21 shown in FIG. 12D is illustrated, but the mirrors between the regions are similarly applied to the dichroic filter 21 shown in FIGS. 12A to 12C and the dichroic filter 16 shown in FIG. (Furthermore, in the first and second embodiments, the shape of the lens at the position corresponding to the mirror of the second fly-eye lens 4 is made smaller than that of other lenses).

<Combination of liquid crystal panel and OSR element>
Next, a modification example in which the liquid crystal panel is combined with the OSR element will be described. In the case of the two-plate transmission type of the first embodiment, two colors of blue and green are displayed on one liquid crystal panel 13 (FIG. 6). In the second and third embodiments, one liquid crystal panel 22 is displayed. 3 or more colors are displayed (FIGS. 11 and 13). For this reason, when considering liquid crystal panels of the same size, the resolution of the screen becomes coarse. As a method for solving this, in Example 2, the number of divisions of red and green is increased as compared with the number of divisions of blue, and the effective resolution is increased by utilizing human visual characteristics (FIG. 13 (a), (B)).

  As another method, an optical element called an OSR (Optical Super Resolution) element (reference: http://www1.olympus.co.jp/jp/imsg/LineUp/HMD/FMD700/tech.html) is used as a liquid crystal panel. You may use in combination. The OSR element is an optical element in which a polarization control element and a birefringent plate are combined, and light emitted from the pixel can be shifted pixel by pixel by controlling the voltage of the polarization control element. As a result, the effective resolution is increased, and a small and highly efficient image display apparatus can be realized.

<Others>
In the first to third embodiments described above, a dichroic filter is used as a means for reflecting a light beam in a specific wavelength band among the light beams from the discharge lamp. However, the present invention is not limited to this, and for example, a hologram element or the like may be used.

  Moreover, in the above Example 1- Example 3, the dichroic filter was arrange | positioned in the conjugate position with the light emission part of a discharge lamp. However, the present invention is not limited to this. For example, in the first and second embodiments, the dichroic filter plays a role in the second fly-eye lens 4 and the PS converter 5 (FIGS. 1 and 9) in the vicinity of the conjugate position. An optical component may be attached.

  Further, in the above first to third embodiments, a discharge lamp is used as a light source, and light beams from the discharge lamp are made incident on a dichroic filter, so that light beams in different wavelength bands are emitted from spatially different regions. Then, it is made to enter the condenser lens. However, the present invention is not limited to this. For example, as a light source, a plurality of laser oscillators that oscillate light in different wavelength bands are used, and light beams in different wavelength bands are emitted from spatially different regions by these laser oscillators. You may make it inject into a condenser lens.

  In the first to third embodiments, the present invention is applied to the liquid crystal projector. However, the present invention may be applied to a projection type image display apparatus other than the liquid crystal projector.

It is a figure which shows the optical system of the 2 plate-type liquid crystal projector by this invention. It is a figure which shows the structural example of the dichroic filter of FIG. It is a figure which shows an example of the light recycling optical path in the liquid crystal projector of FIG. It is a figure which shows the optical path of the red light in the liquid crystal projector of FIG. It is a figure which shows the optical path of the green and blue light in the liquid crystal projector of FIG. It is a figure which shows the structure of the liquid crystal panel 13 of FIG. It is a figure which shows the other example of the optical path of green and blue light in the liquid crystal projector of FIG. It is a figure which shows the other structural example of the liquid crystal panel 13 of FIG. It is a figure which shows the optical system of the single-plate-type liquid crystal projector by this invention. FIG. 10 is a diagram illustrating a configuration of the dichroic filter in FIG. 9. It is a figure which shows the structure of the liquid crystal panel of FIG. FIG. 10 is a diagram illustrating another configuration example of the dichroic filter in FIG. 9. It is a figure which shows the other structural example of the liquid crystal panel of FIG. It is a figure which shows the optical system of the single-plate-type liquid crystal projector by this invention. It is a figure which shows the example of a change of a structure of the dichroic filter of FIG.12 (d). It is a figure which shows the example of a change of a structure of a 2nd fly eye lens.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Reflector 3 1st fly eye lens 4 2nd fly eye lens 5 PS converter 6 Condenser lens 7 Dichroic mirror 8 Reflection mirror 9 Reflection mirror 10 Field lens 11 Transmission type liquid crystal panel 12 Field lens 13 Transmission type liquid crystal panel 14 Color Synthetic prism 15 Projection lens 16 Dichroic filter 21 Dichroic filter 22 Transmission type liquid crystal panel 101 Micro lens 202 Reflector 205 Rod integrator

Claims (15)

In a projection-type image display device comprising: an illumination device including a light source; a light modulation element that modulates illumination light from the illumination device according to a video signal; and a projection lens that forms an image of the light modulation element.
The lighting device includes:
Illumination light separating means for emitting light beams in different wavelength bands from spatially different regions, and
An optical component that converts the light flux of each wavelength band from the illumination light separating means into a light flux of different angular distribution and makes it incident on the light modulation element;
An image display device, wherein the light modulation element is provided with a microlens array for condensing light beams in respective wavelength bands having different incident angle distributions from the optical component to corresponding pixels. The image display device according to claim 1,
The illumination device further includes a reflector that reflects light from the light source and outputs the reflected light to the light modulation element,
The illumination light separating means is an optical component that transmits a light beam of a predetermined wavelength band out of the light beam from the light source, reflects the light beam of another wavelength band and returns it to the reflector, and is divided into a plurality of regions. An image display device characterized in that each optical region has a different wavelength band for transmission. The image display device according to claim 2,
The image display device, wherein the light source is a discharge lamp. The image display device according to claim 2,
An image display device, wherein the reflector has a parabolic shape. The image display device according to claim 2,
The image display device characterized in that the illumination light separating means is a dichroic filter. The image display device according to claim 2,
The image display device according to claim 1, wherein the illumination light separating means is a hologram element. The image display device according to claim 2,
The illumination light separating means is divided into three regions in a stripe shape, the central region transmits a high-intensity wavelength band of the luminous flux from the discharge lamp, and both end regions are respectively separated from the discharge lamp. An image display device that transmits a low-intensity wavelength band of the luminous flux. The image display device according to claim 2,
The illumination light separating means includes an area that transmits the red wavelength band, an area that transmits the green wavelength band, an area that transmits the blue wavelength band, and an area that transmits the yellow wavelength band or all visible light wavelength bands. Divided,
The light modulation element is provided with a pixel that displays red, a pixel that displays blue, a pixel that displays green, and a pixel that displays yellow or white, corresponding to the area of the illumination light separating unit. An image display device characterized by that. The image display device according to claim 2,
The illumination light separating means is divided into five or more regions, and the number of regions that transmit the blue wavelength band is smaller than the number of regions that transmit the other wavelength bands,
In the image display device, the number of pixels that display blue is smaller than the pixels that display other colors corresponding to the area of the illumination light separating unit. The image display device according to claim 2,
The illuminating device includes first and second fly-eye lenses for equalizing an illuminance distribution of a light beam from the light source, and a polarization conversion element that converts the light beam from the light source into specific linearly polarized light. And
The image display device, wherein the illumination light separating means is disposed between the second fly-eye lens and the polarization conversion element. The image display device according to claim 2,
The illuminating device includes first and second fly-eye lenses for uniformizing an illuminance distribution of a light beam from the light source, and a polarization conversion element that converts the light beam from the light source into specific linearly polarized light. And
The image display apparatus, wherein the illumination light separating means is attached to the second fly-eye lens. The image display device according to claim 2,
The illuminating device includes first and second fly-eye lenses for equalizing an illuminance distribution of a light beam from the light source, and a polarization conversion element that converts the light beam from the light source into specific linearly polarized light. And
The image display device, wherein the illumination light separating means is attached to the polarization conversion element. The image display device according to claim 2,
The illumination device further includes an optical system having a conjugate point at which an image of the light source is formed in the optical path of the illumination light,
The image display device, wherein the illumination light separating means is disposed in the vicinity of the conjugate point. The image display device according to claim 2,
The illumination light separating means is divided into two regions, and transmits two wavelength bands in at least one region,
An image display comprising two light modulation elements, wherein at least one of the light modulation elements is provided with a microlens array for condensing light beams of two wavelength bands to corresponding pixels, respectively. apparatus. The image display device according to claim 14,
The illumination light separating means is divided into a region transmitting the blue wavelength band and the red wavelength band, and a region transmitting the green wavelength band and the red wavelength band,
An image display device, wherein one light modulation element is provided with a microlens array for condensing a light beam in a blue wavelength band and a green wavelength band on a corresponding pixel.

Images